US20050062299A1 - Sweep forming assembly and method - Google Patents
Sweep forming assembly and method Download PDFInfo
- Publication number
- US20050062299A1 US20050062299A1 US10/976,417 US97641704A US2005062299A1 US 20050062299 A1 US20050062299 A1 US 20050062299A1 US 97641704 A US97641704 A US 97641704A US 2005062299 A1 US2005062299 A1 US 2005062299A1
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- US
- United States
- Prior art keywords
- bumper
- roller
- flexing
- bumper structure
- sweep
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Abandoned
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Classifications
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B21—MECHANICAL METAL-WORKING WITHOUT ESSENTIALLY REMOVING MATERIAL; PUNCHING METAL
- B21D—WORKING OR PROCESSING OF SHEET METAL OR METAL TUBES, RODS OR PROFILES WITHOUT ESSENTIALLY REMOVING MATERIAL; PUNCHING METAL
- B21D11/00—Bending not restricted to forms of material mentioned in only one of groups B21D5/00, B21D7/00, B21D9/00; Bending not provided for in groups B21D5/00 - B21D9/00; Twisting
- B21D11/08—Bending by altering the thickness of part of the cross-section of the work
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B21—MECHANICAL METAL-WORKING WITHOUT ESSENTIALLY REMOVING MATERIAL; PUNCHING METAL
- B21D—WORKING OR PROCESSING OF SHEET METAL OR METAL TUBES, RODS OR PROFILES WITHOUT ESSENTIALLY REMOVING MATERIAL; PUNCHING METAL
- B21D5/00—Bending sheet metal along straight lines, e.g. to form simple curves
- B21D5/06—Bending sheet metal along straight lines, e.g. to form simple curves by drawing procedure making use of dies or forming-rollers, e.g. making profiles
- B21D5/08—Bending sheet metal along straight lines, e.g. to form simple curves by drawing procedure making use of dies or forming-rollers, e.g. making profiles making use of forming-rollers
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B21—MECHANICAL METAL-WORKING WITHOUT ESSENTIALLY REMOVING MATERIAL; PUNCHING METAL
- B21D—WORKING OR PROCESSING OF SHEET METAL OR METAL TUBES, RODS OR PROFILES WITHOUT ESSENTIALLY REMOVING MATERIAL; PUNCHING METAL
- B21D7/00—Bending rods, profiles, or tubes
- B21D7/08—Bending rods, profiles, or tubes by passing between rollers or through a curved die
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B60—VEHICLES IN GENERAL
- B60R—VEHICLES, VEHICLE FITTINGS, OR VEHICLE PARTS, NOT OTHERWISE PROVIDED FOR
- B60R19/00—Wheel guards; Radiator guards, e.g. grilles; Obstruction removers; Fittings damping bouncing force in collisions
- B60R19/02—Bumpers, i.e. impact receiving or absorbing members for protecting vehicles or fending off blows from other vehicles or objects
- B60R19/18—Bumpers, i.e. impact receiving or absorbing members for protecting vehicles or fending off blows from other vehicles or objects characterised by the cross-section; Means within the bumper to absorb impact
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B60—VEHICLES IN GENERAL
- B60R—VEHICLES, VEHICLE FITTINGS, OR VEHICLE PARTS, NOT OTHERWISE PROVIDED FOR
- B60R19/00—Wheel guards; Radiator guards, e.g. grilles; Obstruction removers; Fittings damping bouncing force in collisions
- B60R19/02—Bumpers, i.e. impact receiving or absorbing members for protecting vehicles or fending off blows from other vehicles or objects
- B60R19/03—Bumpers, i.e. impact receiving or absorbing members for protecting vehicles or fending off blows from other vehicles or objects characterised by material, e.g. composite
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B60—VEHICLES IN GENERAL
- B60R—VEHICLES, VEHICLE FITTINGS, OR VEHICLE PARTS, NOT OTHERWISE PROVIDED FOR
- B60R19/00—Wheel guards; Radiator guards, e.g. grilles; Obstruction removers; Fittings damping bouncing force in collisions
- B60R19/02—Bumpers, i.e. impact receiving or absorbing members for protecting vehicles or fending off blows from other vehicles or objects
- B60R19/18—Bumpers, i.e. impact receiving or absorbing members for protecting vehicles or fending off blows from other vehicles or objects characterised by the cross-section; Means within the bumper to absorb impact
- B60R2019/1806—Structural beams therefor, e.g. shock-absorbing
- B60R2019/1813—Structural beams therefor, e.g. shock-absorbing made of metal
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B60—VEHICLES IN GENERAL
- B60R—VEHICLES, VEHICLE FITTINGS, OR VEHICLE PARTS, NOT OTHERWISE PROVIDED FOR
- B60R19/00—Wheel guards; Radiator guards, e.g. grilles; Obstruction removers; Fittings damping bouncing force in collisions
- B60R19/02—Bumpers, i.e. impact receiving or absorbing members for protecting vehicles or fending off blows from other vehicles or objects
- B60R19/18—Bumpers, i.e. impact receiving or absorbing members for protecting vehicles or fending off blows from other vehicles or objects characterised by the cross-section; Means within the bumper to absorb impact
- B60R2019/1806—Structural beams therefor, e.g. shock-absorbing
- B60R2019/1813—Structural beams therefor, e.g. shock-absorbing made of metal
- B60R2019/1826—Structural beams therefor, e.g. shock-absorbing made of metal of high-tension steel
Abstract
A method and apparatus produces a roll formed bumper member comprising of a metal material. The bumper member has a predetermined transverse cross section and a predetermined curvature. A strip bumper structure is fed into a forming assembly along a line level. The bumper structure has the predetermined transverse cross section and an essentially straight longitudinal configuration. The forming assembly has a driven support roller and a pair of driven cooperating flexing rollers. A first roller of the pair of flexing rollers is positioned to deflect the bumper structure out of the line level. A second roller of the pair of flexing rollers is mounted to revolve about the first roller. The support roller and the pair of cooperating flexing rollers are driven for feeding the bumper structure between the pair of cooperating and counter rotating flexing rollers. Revolving the second flexing roller about the first flexing roller flexes the bumper structure between the support roller and the first flexing roller imparting a permanent longitudinal curvature to the bumper structure.
Description
- This is a divisional application of U.S. application Ser. No. 10/169,994, filed Sep. 23, 2002, which is the U.S. National Phase of International Application PCT/CA01/00026, filed Jan. 8, 2001, which in turn claims priority to U.S. Provisional Patent Application No. 60/176,010, filed Jan. 14, 2000, all of which are incorporated herein in their entirety by reference.
- 1. Field of the Invention
- The present invention relates to vehicle bumpers and methods for producing the same.
- 2. Background of the Invention
- Motor vehicles are typically provided with front and rear bumpers to protect the vehicle in the event of impact. Vehicle bumpers are typically formed from a strip of sheet steel that is shaped by roll forming in a roll forming assembly to have a predetermined transverse cross section that rigidifies the bumper and resists deformation during impact. Bumpers are also provided with a predetermined curvature in the longitudinal direction to provide a bumper that conforms to the shape of the vehicle in the “cross car” or side-to-side direction.
- The degree of longitudinal curvature of the bumper is referred to as bumper “sweep” in the industry. The degree of bumper sweep is a general measure of the radius of curvature of the bumper. A basic commercial quantitative description of bumper sweep is obtained by measuring a chord length of 60 inches (1.524 m) along the bumper and determining the maximum distance between the bumper and the chord along a line perpendicular to the chord. The distance is measured in inches (centimeters) and converted to a sweep number by determining the number of eighths of an inch (0.3175 cm) in the measured distance.
- Bumpers in commercial use typically have sweeps of approximately zero (i.e., a substantially straight bumper) up to approximately 50, although bumpers having a sweep as high as 80 are used in vehicle construction.
- It is well known that the primary objectives of vehicle parts manufacturers is to produce high strength bumpers that resist deformation during impact, but that are also relatively light weight. The goal of minimizing weight can be achieved by reducing the thickness or gauge of the bumper, thereby using less metal to construct the bumper. Minimizing vehicle weight is important because lighter weight vehicles are easier to transport prior to sale and are more fuel efficient for the vehicle owner. The manufacturer can reduce metal thickness and still meet safety requirements by using higher strength steel to construct the bumper.
- The type of metal used for bumper construction is thus a major determinant of bumper weight. Most commercial bumpers, however, are constructed of relatively mild grades of steel because mild steel grades are easier for the parts manufacturer to sweep form during manufacture. High strength low alloy (HSLA) grade steel is an example of such a grade of steel widely used commercially for bumper construction.
- HSLA steel is available in grades having a KSI minimum yield strength of from 35 up to 80 (i.e., a MPa minimum yield strength of from 240 to 550). Grades of steel above HSLA are also commercially available, including dual phase and martinsitic grades of steel, but most parts manufacturers are generally not able to produce a satisfactory commercial bumper with a significant degree of bumper sweep using these higher steel grades.
- Martinsitic steel having a tensile strength of up to 220 KSI (1516 MPa) is commercially available. Generally, any steel having a KSI greater than 80 (240 MPa) can be considered an ultra high strength steel. The rigidity and structural strength provided to the bumper by the transverse cross section makes the sweeping process difficult and limits the strength of the steel most manufacturers can use to construct the bumper.
- More particularly, during manufacturing, a strip of sheet steel is roll formed in a series of pairs of roll forming rollers that gradually shape the steel in a transverse direction to provide the predetermined transverse bumper cross section. An initially shaped bumper structure emerges from a position of exit of the roll forming assembly as an elongated, longitudinally straight, continuous structure. Typically, the initially formed bumper structure is provided with the desired degree of longitudinal curvature (the terms “bumper sweep” and “longitudinal curvature” are used interchangeably in the present application) immediately after the roll forming operation in a separate sweep forming assembly positioned at the position of exit of the roll forming assembly.
- The initially shaped bumper structure emerges from the sweep forming assembly as a finally shaped continuous bumper structure. By “finally shaped” it is meant that the desired degree permanent curvature has been imparted to the bumper structure in both the transverse and longitudinal directions so that the bumper structure has the predetermined transverse bumper cross section and the predetermined longitudinal curvature. The finally shaped bumper structure is then fed into a cutting assembly positioned immediately downstream of the sweep forming assembly. The cutting assembly cuts the finally shaped bumper structure into individual bumper members of predetermined length, each bumper member thus having the predetermined transverse bumper cross section and the predetermined longitudinal curvature.
- Known prior art sweep forming assemblies are not commercially usable to provide a wide range of bumper sweep when high strength steel is used to construct the bumper because they use either what is effectively a form of extrusion or a bending operation to impart bumper sweep. One prior art method, for example, of providing bumper sweep uses a series of blocks, each block having a central opening that is generally the same size and shape as the transverse cross section of the bumper structure. The series of blocks is positioned so that the initially shaped bumper structure passes through the openings as it moves out of the roll forming assembly in the downstream direction. Selected blocks are raised so that the path formed by the openings is not straight, thereby requiring the bumper structure to deform in the longitudinal direction as it is forced through the openings. A degree of permanent curvature is thereby imparted to the bumper structure.
- This method is, in effect, a form of extrusion and has several disadvantages. The metal-to-metal sliding engagement between the bumper structure and the sides of the openings in the blocks wears the metal of the bumper structure and the metal of the blocks. The metal-to-metal sliding engagement limits the speed at which the bumper structure can pass through the assembly line and thus limits the production capacity of a manufacturing plant. This method will provide only a limited degree of sweep and is not commercially feasible for high strength steel bumper manufacturing.
- Another sweep forming assembly which has been used commercially in the past several years utilizes a series of longitudinally spaced movable upper rollers and a series of longitudinally spaced fixed lower rollers that cooperate to bend the bumper structure after it is roll formed. The lower rollers are disposed below the advancing bumper structure and support the same. The upper rollers are disposed above the advancing bumper structure and are vertically movable. The rollers are arranged so that one upper roller is vertically centered between two lower rollers. The sweep is imparted by moving the upper rollers vertically downwardly into engagement with an upper surface of the advancing initially shaped bumper structure. The upper rollers exert a downward force on the bumper structure sufficient to bend the bumper structure between an associated pair of lower fixed rollers, thereby imparting a degree of sweep to the bumper structure.
- The method performed by this assembly is not effective when harder grades of steel are used in bumper structure construction because hard steel grades require forces of great magnitude to bend the steel. These high magnitude bending forces are undesirable because when a force of sufficient magnitude to bend the hard steel is applied by the upper rollers, the upper rollers tend to permanently deform the predetermined bumper cross section of the bumper structure. More particularly, the vertical sides of a hard steel bumper structure tend to pucker uncontrollably, crease or tear under the bending force of the upper rollers. Bending operations also do not provide uniform longitudinal bumper curvature when harder grades of steel are used.
- Another sweep forming assembly that bends the advancing bumper structure to impart bumper sweep is disclosed in U.S. Pat. No. 4,530,226. The '226 sweep forming assembly includes three forming stations mounted on a base assembly positioned at the end of a roll forming assembly. Each station includes a pair of cooperating forming rolls. The middle station also includes an idler roller longitudinally spaced from the pair of forming rolls. The bumper in the '226 assembly is permanently deformed to introduce a bumper structure primarily by the interaction of the rollers in the middle station. The first and third stations primarily guide the bumper structure through the middle station.
- The pair of forming rollers and the idler roller of the middle station of the '226 assembly are longitudinally spaced and transversely off-set from one another (where “transversely” is defined with respect to the bumper structure and refers to a direction perpendicular to the longitudinal extent thereof) to permanently deform the elongated bumper structure in the transverse direction. Specifically, the pair of forming rollers drive the bumper structure over the transversely offset single idler roller which is fixedly mounted on the middle station downstream of the paired forming rollers thereof. The paired forming rollers of each of the three stations are positioned so that the center line of each forming station (i.e., a line between the axes of rotation of each pair of forming rollers) is maintained in a generally perpendicular relationship with the tangential path of the bumper structure as it passes longitudinally through the three forming stations. Thus, opposing transversely directed forces are applied to the bumper structure between the paired rollers of the middle station and the idler roller of the middle station of the '226 assembly which bend the portion of the bumper structure therebetween to impart sweep. The '226 assembly utilizes opposing transversely directed forces applied to the bumper structure at longitudinally spaced positions to create a bending force applied along the portion of the bumper structure between the forming rollers of the middle station and the idler roller of the middle station to impart sweep. Thus, the '226 assembly can impart only a limited degree of sweep and is not suited to providing sweep in high strength metals such as martinsitic grades of steel. The '226 assembly is used to impart a sweep up to approximately 30 in a bumper constructed of HSLA steel. Other examples of assemblies for sweep forming bumpers are shown in references U.S. Pat. Nos. 4,354,372 and 5,813,594.
- It is well known that every metal material has a characteristic modulus of elasticity and that if a metal material such as steel is deformed within its elastic limits by applied forces, the metal material returns to its original shape when the forces are removed. Permanent curvature is only imparted to a metal material if it is deformed beyond its elastic limit. Prior art sweep forming assemblies such as the '226 assembly are unsuccessful at sweep forming high strength steel primarily because they rely on a bending force to deform the steel beyond its elastic limit A bending force is a force exerted over a substantial length of a bumper structure to impart sweep. In the '226 assembly, the bending force is exerted along the length of the bumper structure between the paired rollers and the idler roller of the middle station. Bending forces are ineffective at imparting large degrees of sweep to bumper structures constructed using high grades of steel because these grades of steel require such a high degree of force to deform beyond their elastic limits that the bumper structure will uncontrollably pucker or tear, rendering the bumper structure unusable.
- An individual bumper is primarily intended as a protective structure on the vehicle. Thus, it is essential that the structure of each commercially produced bumper be uniform and that there be no creasing, tearing or uncontrolled puckering of its walls to ensure crashworthiness. It is thus essential that the transverse cross section of each bumper not be deformed during the sweep forming operation. Prior art sweep forming assemblies are not able to reliably impart a high degree of sweep to bumpers constructed of relatively high grades of steel such as dual phase and martinsitic grades. A need exists for a sweep forming assembly that can provide a bumper sweep of up to approximately 80 for roll formed bumpers constructed of high strength steel such as dual phase or fully hardened martinsitic grades of steel having a tensile strength of up to 220 KSI (1516 MPa).
- To meet the need identified above, the present invention provides a method for producing a roll formed bumper comprising of a metal material and having a predetermined transverse cross section and a predetermined curvature. A bumper structure is fed into a forming assembly along a line level. The bumper structure has the predetermined transverse cross section and an essentially straight longitudinal configuration. The forming assembly has a driven support roller and a pair of driven cooperating flexing rollers. A first roller of the pair of flexing rollers is positioned to deflect the bumper structure out of the line level and a second roller of the pair of flexing rollers is mounted to revolve about the first roller. The support roller and the pair of cooperating flexing rollers are driven for feeding the bumper structure between the pair of cooperating and counter rotating flexing rollers. Revolving the second flexing roller about the first flexing roller flexes the bumper structure between the support roller and the first flexing roller imparting a permanent longitudinal curvature to the bumper structure.
- Another object of the present invention is to provide a vehicle bumper constructed of a metal material. The metal material is roll formed to provide an elongated bumper structure having a predetermined transverse cross section and a longitudinal extent. The predetermined transverse cross section has one at least partially open side. The longitudinal extent of the bumper structure has a predetermined bumper curvature of about 80 and the metal material has a KSI of at least approximately 120 (an MPa of approximately 827). Preferably the metal material is a steel that has a minimum 0.2 percent offset yield strength of about 120,000 psi (827 MPa) and a ferritic grain structure. More preferably, the metal material is a quenched and tempered steel having a minimum ultimate tensile strength of about 140,000 psi (965 MPa) and a grain structure comprised of ferrite and tempered martinsite. Most preferably, the metal material is a martinsitic steel. A preferred martinsitic steel is a quenched and tempered steel having a minimum ultimate tensile strength of from about 190,000 to about 220,000 psi (from about 1310 MPa to about 1516 MPa) and having an entirely tempered martinsite grain structure. When this preferred martinsitic steel is used, preferably the thickness of the metal material is within the range of approximately 0.8 mm to approximately 1.6 mm and is more preferably within the range of approximately 1.0 mm to approximately 1.3 mm.
- Another object of the present invention is to provide an assembly that will carry out the method previously described, by providing a driven support roller positioned to receive a strip bumper structure at a line level. A driven first flexing roller is positioned to deflect the bumper structure from the line level and a driven second flexing roller cooperates with the first flexing roller for counter rotating therewith. The second flexing roller is movably mounted to revolve about the first flexing roller. An adjustment assembly operably engages the second flexing roller to effect the revolving movement of the second flexing roller about the first flexing roller. The revolving movement effects engagement of the second flexing roller with the bumper structure between the support roller and the first flexing roller and urges the bumper structure against both the support roller and the first flexing roller to impart a permanent longitudinal curvature to the bumper structure.
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FIG. 1 shows a sweep forming assembly constructed according to the principles of the present invention and shows a fragmentary portion of a continuous strip bumper structure extending through the assembly; -
FIG. 2 shows a view of the sweep forming assemblyFIG. 1 in a second adjusted operating position; -
FIG. 3 shows a cross sectional view of the strip bumper structure ofFIG. 1 taken through the line 3-3; -
FIG. 4 shows a cross sectional view of the strip bumper structure ofFIG. 5 taken through the line 4-4; -
FIG. 5 shows a schematic view of a second embodiment of a sweep forming assembly of the present invention; -
FIG. 6 shows a partial sectional end view of the sweep forming assembly ofFIG. 5 ; -
FIG. 7 is a schematic side plan view of an assembly line that includes the sweep forming assembly; -
FIG. 8 is a perspective view of an exemplary individual bumper member; -
FIGS. 9-14 show in fragmentary cross section outer peripheries of a series of pairs of roll forming rollers of a roll forming assembly and a metal strip structure therebetween; and -
FIGS. 15 and 16 show two views of a plurality of roller members of the sweep forming assembly ofFIG. 1 in isolation flexing a bumper structure at a point of flexure. - Referring to
FIG. 7 , thesweep forming assembly 10 is preferably included as part of anassembly line 23 that includes a series of assemblies which cooperate to produce a plurality of individual vehicle bumpers starting from a coiled strip structure of raw metal material. The cooperating assemblies uncoil and progressively shape the strip structure into a continuous metal strip bumper structure and then cut the continuous structure at regular intervals to form individual bumper members. - The
assembly line 23 includes an uncoilingassembly 25 that receives and uncoils a roll of a metal strip structure made of a raw metal material. The coiled portion of the metal strip structure is designated 27 and the uncoiled metal strip structure is generally designated 28. The portion of themetal strip structure 28 exiting the uncoilingassembly 25 passes sequentially through a plurality of assemblies including atemper mill assembly 29, astock straightener assembly 31, an optionalpre-pierce press assembly 33 and aroll forming assembly 37. - The uncoiling
assembly 25,temper mill assembly 29 andstock straightener assembly 31 uncoil, flatten and condition themetal strip structure 28 so that theportion 21 thereof acted on by theseassemblies roll forming assembly 37. Theroll forming assembly 37 includes a plurality of pairs of roll forming rollers, generally designated 39, which progressively shape a transverse cross section in a longitudinally extending portion of the blankmetal strip structure 28. The portion of themetal strip structure 28 exiting theroll forming assembly 37 has a predetermined transverse bumper cross section and is generally referred to as a strip bumper structure, generally designated 53. Thebumper structure 53 generally includes (a) an initially shaped or formedportion 41 and (b) a initially shaped or formedportion 49. The initially shapedportion 41 has the predetermined roll formed transverse bumper cross sectional configuration and an essentially straight longitudinal configuration at the position ofexit 43 of theroll forming assembly 37. Thus, theroll forming assembly 37 provides the continuous longitudinally extending initially shapedbumper structure 41 at the position ofexit 43 thereof and the initially shapedbumper structure 41 moves downstream from there into thesweep forming assembly 10. - Preferably, the
sweep forming assembly 10 shown schematically inFIG. 7 , is positioned on theassembly line 23 immediately downstream of theroll forming assembly 37. Thesweep forming assembly 10 receives the initially shapedcontinuous bumper structure 41 at the position ofexit 43 of theroll forming assembly 37 and provides a predetermined longitudinal bumper curvature to the initially shaped bumper structure to give the bumper structure its final form. The predetermined transverse cross section is not changed by thesweep forming assembly 10. The finally formedportion 49 of thecontinuous bumper structure 53 is fed into acutoff press assembly 45 that thestrip bumper structure 53 into individual bumper members. An exemplaryindividual bumper member 47 is shown in isolation inFIG. 8 . - Preferably, the initially shaped bumper structure entering the
sweep forming assembly 10 is roll formed to have a predetermined transverse cross section that includes 25. one at least partially open side. Two exemplary roll formed bumper structures having one at least partially open side are shown in cross section inFIGS. 3 and 4 . -
FIG. 3 shows the predetermined transverse bumper cross section of the exemplary bumper structure 53 (and of the bumper member 47), which has an open cross section. It can be understood that both the initial shaped and finally shapedportions bumper structure 53 has transversely outwardly extendingwall portions recess 35. The roll formedrecess 35 is defined by acentral wall portion 36 andside wall portions central wall portion 36 has aninner surface 42 and anouter surface 44. Therecess 35 generally defines anopen side 46 of the cross section. The cross section of thebumper structure 53 is referred to as “open” because the oppositetransverse wall portions recess 35 leaving thecentral recess 35 open. -
FIG. 4 shows an exemplary cross-sectional view of the predetermined cross section of an initially shapedbumper structure 74 of an exemplary bumper structure generally designated 75 that has a partially closed cross section. Thebumper structure 75 has transversely inwardly extendingwall portions central wall portion 80 andside wall portions central wall portion 80 has aninner surface 86 and anouter surface 88. Thewall portions central wall portion 80, thereby partially closing the cross section and providing the cross section with a “C” shape. Thebumper structure 75 thus has a partially open side, generally designated 92, that includes anopening 90. - The
sweep forming assembly 10 can be advantageously used to provide bumper sweep to either a bumper structure having an open transverse cross section (such as the exemplary bumper structure 53 ) or to a bumper structure having a partially open cross section (such as exemplary bumper structure 75). - Furthermore, a bumper structure having either an open or partially open cross section can be swept in either of two general directions to provide a finally formed bumper structure that has either an inside sweep or an outside sweep. A finally formed bumper structure is considered to have inside sweep if its radius of curvature is directed outwardly from the inner surface thereof 42 or 86, respectively. The
exemplary bumper member 47 shown inFIG. 8 has an inside sweep. Similarly, a finally formed bumper structure is considered to have an outside sweep if its radius of curvature is directed outwardly from the outer surface thereof 44 or 88, respectively. - As will become apparent, the
sweep forming assembly 10 of the present invention can be constructed and operated to provide a bumper structure having an open cross section with either an inside or an outside predetermined bumper curvature (i.e., bumper sweep) or to provide a bumper structure having a partially open cross section with either an inside or outside predetermined bumper curvature. - The
rollers 39 of aroll forming assembly 37 are spaced to receive themetal strip structure 28 therebetween and that the peripheries of therollers 39 are constructed to progressively shape the transverse cross section.FIGS. 9-14 show the peripheries of upper and lower roller of the series of pairs ofrollers 39 of thetoll forming assembly 37. The complementary pairs of rollers are designated 3 9 a and 39 b; 39 c and 39 d; 39 e and 39 f, 39 g and 39 h; 39 i and 39 j; and 39 k and 39 l. It can be appreciated that when theroll forming assembly 37 is configured to form a strip bumper structure having an open cross section, the outer peripheries of each pair ofrollers 39 are generally of complimentary male and female configuration. The pairs ofrollers 39 are arranged so that the portion of thestrip structure 28 extending through theroll forming assembly 37 is at a constant vertical height. This vertical height is referred to as the “line level” of theroll forming assembly 37. The initially shaped continuous bumper structure 41 (seeFIG. 7 ) emerges from the position ofexit 43 of theroll forming assembly 37 at line level. -
FIGS. 1-2 show a sweep forming assembly, generally designated 10, constructed according to the principles of the present invention. Thesweep forming assembly 10 generally includes abase 12, aprimary carriage assembly 14, a drivensupport member 16, first and second driven flexingrollers auxiliary roller 22. - A fragmentary portion of the
bumper structure 53 is shown interengaged with thesweep forming assembly 10. The downstream direction inFIGS. 1 and 2 is from right to left, as indicated by a straight directional arrow on the right hand side of each ofFIGS. 1 and 2 (spaced slightly above the initially shapedportion 41 of the bumper structure 53). - The driven
support roller 16 and the first driven flexingroller 18 are mounted on thebase 12 of thesweep forming assembly 10 for rotational movement with respect thereto. Thebase 12 is a metal structure, preferably made of steel, and includes abottom plate 84 and a pair of upwardly extending, essentiallyvertical wall plates 86 fixed to theplate 84. Thewall plates 86 are affixed to theplate 84 in transversely spaced, parallel relation to support therollers primary carriage assembly 14 therebetween in a manner described below. Thewall plates 86 are preferably reinforced by horizontally extending top plate fixed between upper portions ofwall plates 86. Thewall structure 89 is also preferably also made of steel. - The driven
support roller 16 and thefirst flexing roller 18 are affixed torespective shafts shaft 88 is rotatably mounted in agear box 92 and eachgear box 92 is, in turn, mounted in arespective wall plate 86 of thebase 12. Similarly, each end of theshaft 88 is rotatably mounted in agear box 94 and eachgear box 94 is, in turn, mounted in a respective wall plate of thebase 12. Thus, theshafts respective rollers - The
primary carriage assembly 14 is pivotally mounted generally between thewall plates 86 on theshaft 90 for pivotal movement with respect to thebase 12. Thus, the axis of rotation of thefirst flexing roller 18 is coaxial with the pivot axis of theprimary carriage assembly 14. Theprimary carriage assembly 14 is a metal structure, preferably made of steel and includes acarriage bottom plate 100 and a pair ofwall plates 102 affixed to thecarriage bottom plate 100. Thewall plates 102 are affixed to thebottom plate 100 in transversely spaced, parallel relation and cooperate to support the second driven flexingroller 20 and portions of anauxiliary carriage assembly 110 therebetween. - The
second flexing roller 20 is fixedly mounted on ashaft 106. Theshaft 106 is rotatably mounted between thewall plates 102 of theprimary carriage assembly 14. - As can be appreciated from a comparison of
FIGS. 1 and 2 , when theprimary carriage assembly 14 is pivoted with respect to thebase 12, thesecond flexing roller 20 moves with theprimary carriage assembly 14 such that pivotal movement of the primary carriage assembly with respect to the base 12 causes pivotal movement of thesecond flexing roller 20 with respect to thefirst flexing roller 20 about the pivot axis defined byshaft 90. The inter-axial distance between the axes of rotation (defined byshafts 90, 106) of the first and second driven flexingrollers primary carriage assembly 14 with respect to thebase 12. - Preferably, the
rollers second flexing rollers bumper structure 53 in the downstream direction. Thesupport roller 16 supports an upstream portion of the bumper structure to resist downward movement of thebumper structure 53 during the flexing operation. Driving thesupport roller 16 minimizes the resistance to the movement of thebumper structure 53 in the downstream direction. - Outer gears 160, 162 are affixed on
respective shafts rollers drive gear respective shafts outer gear 162 drives bothsecondary gears rollers - A primary
carriage adjustment assembly 124 is operatively mounted between the base 12 and theprimary carriage assembly 14 to pivot theprimary carriage assembly 14 with respect to thebase 12 and to hold theprimary carriage assembly 14 in an adjusted operating position thereafter. Theadjustment assembly 124 includes ahousing 126 fixed to thebottom plate 84 of thebase 12 and a lower portion of a vertically extending threadedshaft 128 is rotatably mounted in thehousing 126. Acontrol assembly 130 is operatively engaged with the threadedshaft 128 to control rotation of the threadedshaft 128 with respect to thehousing 126. - The threaded
shaft 128 extends through an opening in thebottom plate 100 of theprimary carriage assembly 14 and between a pair ofsupport wall plates 131 fixed to thebottom plate 100 on opposite transverse sides of the opening in theplate 100. A threadedmember 132 is pivotally mounted between thewall plates 131 bypivot shafts 133. An upper end of the threadedshaft 128 threadedly engages the threadedmember 132. Bidirectional rotation of the threadedshaft 128 causes bidirectional threaded movement of the threadedmember 132 along theshaft 128. Threaded movement of threadedmember 132 along theshaft 128 causes pivotal movement of theprimary carriage assembly 14 with respect to thebase 12. The threaded engagement between theshaft 128 and the threadedmember 132 holds theprimary carriage assembly 14 in an adjusted operating position with respect to the base 12 when rotational movement of theshaft 128 ceases. - The
adjustment assembly 137 is operatively mounted between theprimary carriage assembly 14 and theauxiliary carriage assembly 110 to control movement of the auxiliary carriage assembly with respect to theprimary carriage assembly 14. Specifically, a lower end of a threadedshaft 136 is rotatably mounted in ahousing 138 mounted on thebottom plate 100. An upper end of the threadedshaft 136 threadedly engages a threadedmember 140 mounted to the mountingplate 112. Rotation of the threadedshaft 136 with a control assembly (not shown) causes sliding movement of the auxiliary carriage assembly 110 (through the range of movement provided by theslots 113 and bolts 111) with respect to theprimary carriage assembly 14 to raise and lower theroller 22 with respect to the first andsecond flexing rollers shaft 136 and themember 140 hold the auxiliary carriage assembly in an adjusted operating position with respect to theprimary carriage assembly 14 after rotation of theshaft 136 ceases. - The
auxiliary carriage assembly 110 is movably mounted on theprimary carriage assembly 14, generally between thewall plates 102. Theauxiliary carriage assembly 110 is a metal structure, preferably made of steel and includes anauxiliary mounting plate 112 and a pair ofwall plates 114 affixed to the mountingplate 112. Thewall plates 114 are affixed to the mountingplate 112 in transversely spaced, parallel relation and cooperate to rotatably support theauxiliary roller 22 therebetween. - The
auxiliary carriage assembly 110 is mounted for relative movement with respect to theprimary carriage assembly 14 bybolts 111 that extend throughelongated slots 113 formed in the mountingplate 112 of theauxiliary carriage assembly 110. Specifically, a series ofbolts 111 is mounted in eachwall plate 102 of theprimary carriage assembly 14, eachbolt 111 extending through aslot 113. Movement of theauxiliary carriage assembly 110 with respect to theprimary carriage assembly 14 provides relative movement of theauxiliary roller 22 with respect to the first andsecond flexing rollers auxiliary carriage assembly 110 is moved with respect to theprimary carriage assembly 14 and is held in an adjusted operating position with respect thereto by anadjustment assembly 137. - An optional
exit roller assembly 119 which includes a pair of transversely spacedexit rollers 120 is mounted to the mountingplate 112 of theauxiliary carriage assembly 110. Theexit rollers 120 are idler rollers that rotate aboutshafts 122. Theexit rollers 120 support opposite transverse edges of thebumper structure 53 when the same is cut in the cut offpress 45 which is preferably positioned immediately downstream of the sweep forming assembly 10 (seeFIG. 7 ). Theexit rollers 120 are thus not involved in the sweep forming operation but can be mounted on theassembly 10 as a convenience to the bumper manufacturer. Preferably theexit roller assembly 119 is movably mounted on the mountingplate 112 by bolts or other appropriate structure so that its position can be changed to accommodate a wide range of sweep curvatures. - The manner in which the pivotal position of the
primary carriage assembly 14 with respect to thebase 12 is adjusted can be understood from a comparison ifFIGS. 1 and 2 . - Operation
- The
sweep forming assembly 10 is constructed and arranged to receive at the position ofexit 43 of aroll forming assembly 37 the initially shaped roll formedbumper structure 41 constructed of a metal material and having a predetermined roll formed transverse bumper cross section and a substantially straight longitudinal configuration and to impart a permanent bumper curvature to the bumper structure, thereby providing the finally shapedbumper structure 49 downstream of thesweep forming assembly 10. - The driven
support roller 16 supportsbumper structure 53 at the position of exit of theroll forming assembly 37. The first and second driven flexingrollers bumper structure 53 in the downstream direction and are positioned downstream of the drivensupport roller 16 sufficiently close to flex thebumper structure 53 at a point offlexure 143 between the drivensupport roller 16 and the first and second driven flexingrollers - Preferably, the
support roller 16 and thefirst flexing roller 18 are mounted on the base 12 such that the uppermost point of anouter periphery 146 of thefirst flexing roller 18 is vertically higher than the line level. In thesweep forming assembly 10, theshafts peripheries first flexing roller 18 greater than the radius of thesupport roller 16. Preferably theouter periphery 148 of the drivensupport roller 16 is at line level and theouter periphery 146 of thefirst flexing roller 18 is approximately 2.5 cm (one inch) above line level. Thus, thefirst flexing roller 18 provides a small amount of lift or deflection to thebumper structure 53 as it passes thereover. - Alternatively, the height differential between the
outer peripheries - Generally, to provide sweep to the
bumper structure 53, an assembly operator pivots or revolves thesecond flexing roller 20 in a flexing direction (clockwise from the point of view ofFIGS. 1, 2 , 15 and 16) using thecontrol assembly 130 of the primarycarriage adjustment assembly 124 as previously described. The pivotal movement of theprimary carriage assembly 14 revolves thesecond flexing roller 20 about the pivot axis defined byshaft 90 with respect to thefirst flexing roller 18.FIG. 1 shows the second flexing roller 20 (and therefore the primary carriage assembly 14) in a first pivotal position with respect to thefirst flexing roller 18 andFIG. 2 shows thesecond flexing roller 20 in a second pivotal position with respect to thefirst flexing roller 18. As is considered in more detail below,FIGS. 15 and 16 also illustrate the pivotal movement of thesecond flexing roller 20 in the flexing direction with respect to thefirst flexing roller 18 and shows therollers - Pivotal or revolving movement of the
second flexing roller 20 in the flexing direction exerts a force on the bumper structure which flexes the same at the point offlexure 143 between thefirst flexing rollers 18 and thesupport roller 16. As can be appreciated from a comparison ofFIGS. 1 and 2 (and of 15 and 16), the greater the pivotal movement of thecarriage assembly 14 in the flexing direction, the greater the degree of flexure and thus the greater the degree of permanent curvature imparted to the metal material of thebumper structure 53. - The flexing action of the
bumper structure 53 at the point offlexure 143 can be best understood from a comparison ofFIGS. 15 and 16 which shows therollers FIG. 15 shows thesecond flexing roller 20 in a first position of pivotal adjustment with respect to thefirst flexing roller 18 andFIG. 16 shows thesecond flexing roller 20 in a second position of adjustment after having been pivoted about the axis of rotation of the first flexing 18 in the flexing direction (indicated inFIGS. 15 and 16 by a directional arrow extending outwardly from the axis of rotation of the second flexing roller 20). - The flexing
rollers bumper structure 53 between theirouter peripheries bumper structure 53 that is between theperipheries rollers peripheries shafts rollers 18, 20 (this imaginary line is represented by a dashed line inFIGS. 15 and 16 ). Movement of thesecond flexing roller 20 in the flexing direction moves the imaginary line in a clockwise direction about the axis defined by theshaft 90 and consequently shifts the point of driving engagement of the bumper structure and theouter peripheries rollers outer periphery 146 of thefirst flexing roller 18. Thus, pivotal movement of thesecond flexing roller 20 changes the direction of travel of the portion of the bumper structure between the flexingrollers second flexing roller 20 in the flexing direction, the steeper the slope of the path traveled by the bumper structure between theperipheries support roller 16 is close enough to thefirst flexing rollers 18 such that the bumper structure flexes at a point between therebetween in response to the pivotal or revolving movement of thesecond flexing roller 20 in the flexing direction. - It is now apparent to those skilled in the art that the
support roller 16 must be positioned sufficiently close to the flexingrollers 18 to cause flexure of the metal material beyond the elastic limit thereof in response to the pivotal movement of thesupport roller 20. If thesupport roller 16 were positioned a relatively large distance from the flexingrollers second flexing roller 20 in the flexing direction would not generate a sufficient force to permanently curve the bumper structure, particularly when a high strength steel is used in the bumper structure construction. If thesupport roller 16 were on one assembly or station and the first andsecond flexing rollers support roller 16 supports the portion of the bumper structure immediately upstream of the first and second flexing rollers in opposition to the flexing force exerted by therollers support roller 16 be paired with an upper roller. - With reference again to
FIGS. 15 and 16 , it can be appreciated that the greater the clockwise movement of the second flexing roller about the pivot axis defined byshaft 90, the greater the degree of bumper structure flexure and therefore the greater the degree of permanent longitudinal curvature. Generally, the flexingrollers bumper structure 53 at apoint 143 slightly upstream of the point of driving engagement between thebumper structure 53 and the flexingrollers support roller 18 with respect to the flexingroller 20 changes. - The
sweep forming assembly 10 is configured to provide thebumper structure 53 with an inside sweep. Thus, the open crosssection bumper structure 53 emerges from the exemplaryroll forming assembly 37 in the orientation shown inFIG. 3 with theinside surface 42 facing upwardly. It can be understood that thebumper structure 53 could be rotated 180 degrees and thesweep forming assembly 10 reconfigured in a manner described below if it was desired to sweep thebumper structure 53 in the outside direction. - The outer peripheries of the
rollers bumper structure 53. Specifically, theouter peripheries rollers roll forming rollers 39 k and 39 l ofFIG. 14 and conform to the respective sides of thebumper structure 53 in surface-to-surface driving engagement therewith. As mentioned, the inter-axial distance between theshafts outermost peripheries rollers second roller 20 with respect to thefirst flexing roller 18. Preferably this inter-periphery distance is approximately equal to the thickness of the metal of thebumper structure 53. Since theouter peripheries second flexing rollers rollers outer peripheries - A high degree of bumper curvature can be imparted to a
bumper structure 53 through angular adjustment of thesecond flexing roller 20 relative to thefirst flexing roller 18. The degree of curvature depends upon a number of factors, including the modulus of elasticity of the metal material of thebumper structure 53, the thickness of the metal material and the cross sectional configuration of the bumper structure. However, there may be a limit to the degree of curvature that can be imparted to a particular bumper structure using the flexing rollers, 18, 20 and thesupport roller 16. Excessive pivotal movement of thesecond flexing roller 20 in a flexing direction may nonetheless cause a tearing or uncontrolled puckering of the wall portions of thebumper structure 53. Theside wall portions 38, 40 (seeFIG. 3 ) are particularly susceptible to deformation or tearing during sweep forming. - The
auxiliary roller 22 can be used to increase of the degree of sweep imparted to abumper structure 53 beyond that which can be achieved using therollers auxiliary roller 22 is preferably an idler roller. Theauxiliary roller 22 is positioned downstream of the first and second driven flexing rollers such that the portion of thebumper structure 53 driven downstream by the flexingrollers bumper structure 53 beyond the elastic limit of the metal material. - To increase the curvature of the
bumper structure 53 using theauxiliary roller 22, the operator adjusts the position of theauxiliary carriage assembly 110 with respect to theprimary carriage assembly 14 using theadjustment assembly 137 as aforesaid to move theroller 22 upwardly into engagement with the downwardly facing side of thebumper structure 53.FIG. 1 shows theauxiliary roller 22 spaced slightly below and thus out of engagement with thebumper structure 53.FIG. 2 shows the auxiliary roller 22 (and auxiliary carriage assembly 110) moved upwardly with respect to theprimary carriage assembly 14 and shows theauxiliary roller 22 in engagement with thebumper structure 53. - The
length 155 of thebumper structure 53 between the first andsecond flexing rollers auxiliary roller 22 is bent as therollers bumper structure 53 into theauxiliary roller 22. It has been found that this bending can impart an increased amount of sweep to a given bumper structure beyond that imparted by the flexing operation alone. Flexure imparted to thebumper structure 53 at the point offlexure 143 by the flexingrollers bumper structure 53 and theauxiliary roller 22 imparts a second degree of permanent curvature to thebumper structure 53. - An advantage of the
sweep forming assembly 10 is that bothcarriage assemblies sweep forming assembly 10 is operating. Thus, thesweep forming assembly 10 can be adjusted “on-the-fly”. This capability allows the operator to monitor the condition of thebumper structure 53 exiting from thesweep forming assembly 10 as the operator is adjusting the same. - If, for example, the
second flexing roller 20 is pivoted too far in the flexing direction, thereby causing the wall portions of theparticular bumper structure 53 to tear slightly or pucker uncontrollably before the desired degree of sweep is achieved, the operator can ‘back off’ thesecond flexing roller 20 until no puckering and/or tearing is observed. The operator can then further increase the amount of imparted sweep by moving theauxiliary roller 22 in the sweep increasing direction to increase the degree of sweep. - It can be understood that because the operator is able adjust the positions of the
rollers assembly 10 is operating, the operator is able to produce a wide range of settings on thesweep forming assembly 10. The flexingroller 20 and theauxiliary roller 22 can be thought of as the “coarse” and “fine” adjustments, respectively, of thesweep forming assembly 10. The adjusting procedure followed for a particular bumper structure can be varied to best impart sweep to the particular bumper structure. - Driving the
rollers bumper structure 53 by thesweep forming assembly 10 compared to a sweep forming assembly with passive rollers because driving thebumper structure 53 prevents the same from buckling as it passes through thesweep forming assembly 10. Pushing the bumper structure in the downstream direction through the sweep forming assembly would tend to cause the bumper structure to buckle and buckling deforms the bumper structure, particularly the predetermined transverse bumper cross section. Driving therollers bumper structure 53 through thesweep forming assembly 10, thereby preventing buckling. - The
sweep forming assembly 10 provides the initially shapedbumper structure 41 emerging from the position ofexit 43 of theroll forming assembly 37 with the desired degree of permanent bumper curvature. As mentioned, after the initially shapedcontinuous bumper structure 41 is provided with the desired amount of sweep, thebumper structure 53 has achieved its final bumper shape. Thebumper structure 53 is then cut into individual bumper members, one of which is shown inFIG. 8 and generally designated 47. - The individual bumper members can be used to provide vehicle bumpers. Alternatively, one (or more) bumper members can be mounted to a bumper mounting structure to close the one at least partially open side of each bumper member to form a bumper beam assembly having a closed cross section. The method of mounting one or more individual bumper members on a mounting structure to form a bumper beam assembly having a closed cross section is disclosed in the commonly assigned U.S. patent application Ser. No. 60/100,835 which application is hereby incorporated by reference into the present application for all material disclosed therein.
- A sweep forming assembly for providing bumper sweep to an initially shaped bumper structure having a partially closed cross section is represented in
FIGS. 5 and 6 and is generally designated 210. The construction and operation ofsweep forming assembly 210 is similar to that ofsweep forming assembly 10. Thesweep forming assembly 210 is shown schematically inFIG. 5 to show the differences between theassemblies - A driven
support roller 216, a first and a second driven flexingroller auxiliary roller 222 of theassembly 210 are shown in isolationFIG. 5 . The general structure and operation of the base, the primary carriage assembly, the auxiliary carriage assembly and associated structures of thesweep forming assembly 210 and the manner in which therollers FIGS. 1 and 2 ) and described above for thesweep forming assembly 10. Consequently, the base, carriage assemblies and associated structures are omitted from theFIG. 5 . Portions of thesweep forming assembly 210 that are identical to portions of thesweep forming assembly 10 are identified by identical reference numerals and are not described further. Thegears - The main difference between the
sweep forming assemblies exemplary bumper structure 75 shown inFIG. 4 ) is sweep formed in thesweep forming assembly 210, a pair ofsnake arbors 230 are provided in the interior thebumper structure 75, onearbor 230 on each transverse side of the bumper structure. Opposite ends of thearbors 230 are secured tobracket members 232, 233 (fragments of which are shown inFIG. 5 and one of which is shown inFIG. 6 ) which extend through theopening 90 of thebumper structure 75. An upper end portion of thebracket member 232 is preferably secured to structure on the auxiliary carriage assembly 238 (shown in end view inFIG. 6 ). Thebracket member 233 is preferably mounted to the base. Two pairs oftie rods 244 are secured between thebrackets 232, 233 (one pair on each side of the bumper structure 75) and a series ofblocks 246 are mounted on the rods. -
FIG. 6 shows a partial view of thesweep forming assembly 210 looking into the exit of theassembly 210 in the upstream direction. Thefirst flexing roller 218 engages substantially the entire outside surface of thebumper structure 75. Thesecond flexing roller 220 includeslateral roller portions 250 of lesser radius which rollingly engage upper exterior edges 252 of thebumper structure 75 and acentral roller portion 254 of greater radius which extends through theopening 90 in the predetermined cross section and engages a central portion of thesurface 86 of the interior of thebumper structure 75. Thus, asnake arbor 230 extends on each side of thecentral portion 254 of thesecond flexing roller 220. Thesnake arbors 230 andbrackets 232 slidingly engage inside surfaces of thebumper structure 75. Alternatively, thearbors 230 and/or thebrackets 232 can be constructed to include a plurality of rollers (not shown) constructed and arranged to rollingly engage upwardly and downwardly facinginterior surfaces - Each bumper structure is preferably formed from strips of raw sheet metal material, preferably steel. One preferred steel for use with the
sweep forming assembly 10 is a martinsitic steel having a KSI of between approximately 190 (referred to as a martinsitic 190) to approximately 220 (referred to as a martinsitic 210) (or an MPa of between 1310 and 1516). These steels are readily commercially available and are referred to respectively by the trade names “Inland M190” and “Inland M220” steel. The martinsitic 190 and the martinsitic 220 are quenched and tempered steels characterized by minimum ultimate tensile strengths of 190,000 and 220,000 psi, respectively (1310 MPa and 1516 MPa, respectively). Both the martinsitic 190 and the martinsitic 220 have a grain structure comprised entirely of tempered martinsite. - Another preferred steel for use with the
sweep forming assembly 10 is a dual-phase 140T quenched and tempered steel. This steel is readily commercially available and is referred to by the trade name “Inland Di-Form 140T” steel. The dual-phase 140T is characterized by a minimum ultimate tensile strength of 140,000 psi, (965 MPa) and has a grain structure comprised of ferrite and tempered martinsite. - Another preferred steel for use with the
sweep forming assembly 10 is a High Strength Low Alloy (HSLA) 120XF steel. Although this steel is referred to as “High Strength Low Alloy”, it is not actually one of the High Strength Low Alloy grades; it is referred to as being “High Strength Low Alloy”, however, because it is manufactured by a similar process. The HSLA 120XF is characterized by a minimum 0.2% offset yield strength of 120,000 psi (827 MPa) and has an entirely ferritic grain structure. This steel is readily commercially available and is referred to by the trade name “LTV 120 XF steel”. - These steels are preferably used to manufacture individual bumper members that each have a uniform steel wall thickness. Preferably the bumper members are constructed of a steel having a strength of at least approximately 120 KSI (827 MPa) and more preferably are constructed of a steel having a strength greater than about 180 KSI (1240 MPa).
- For example, a bumper can be constructed of a roll formed metal material by providing an elongated roll formed bumper member having a predetermined transverse bumper cross section and a longitudinal extent, the predetermined transverse bumper cross section having one at least partially open side, and the longitudinal extent having a predetermined bumper curvature of from about zero to about eighty and the metal material having a KSI of at least 120 (827 MPa). Preferably, the metal material is a steel that has a minimum 0.2 percent offset yield strength of about 120,000 psi (827 MPa) and an entirely ferritic grain structure. More preferably, the metal material is a quenched and tempered steel having a minimum ultimate tensile strength of about 140,000 psi (965 MPa) and a grain structure comprised of ferrite and tempered martinsite. Most preferably, the metal material is a quenched and tempered steel having a minimum ultimate tensile strength of from about 190,000 to about 220,000 psi (from about 1310 MPa to about 1516 MPa) and having an entirely tempered martinsite grain structure. When a steel having a strength of at least approximately 180 KSI (1240 Mpa) is used in the construction, the preferred steel wall thickness of the bumper member is within the range of from about 0.8 mm to about 1.6 mm, and is more preferably within the range of from about 1.0 mm to about 1.3 mm. When a steel having a KSI of approximately 120 to approximately 180 (827 to 1240 MPa) is used in the construction, the wall thickness of each bumper member is preferably approximately 2.0 mm. The
sweep forming assemblies - It can be appreciated that the description of the construction and operation of the sweep forming assembly is exemplary only, and not intended to limit the scope of the invention. For example, a sweep forming assembly can be constructed according to the principles of the present invention which provides inside or outside bumper sweep of over 80. Embodiments are contemplated and have been constructed which provide sweep as high as approximately 155.
- It is also within the scope of the present invention to provide a driven mating roller vertically spaced above the driven
support roller 16 when relatively high degrees of sweep (above approximately 80, for example) are being provided to an initially shaped bumper structure, or when the thickness of the metal material is relatively high or both. It has been found that the additional roller provides greater stability to the bumper structure during the sweep forming operation. - Similarly, the description of the metal materials used in bumper construction and the descriptions of bumper construction are intended to illustrate the invention and are not intended to limit the scope of the invention. Materials having properties outside the ranges described herein are also contemplated to be used in bumper construction. For example, steel having a hardness below 120 (827 Mpa) can be swept on a sweep forming assembly constructed according to the principles described herein.
- Similarly, the bumper cross sections described and illustrated are exemplary and are intended to illustrate general types of cross sections and not to limit the range of bumper structures that can be swept using the sweep forming assembly or to limit the bumper members constructed according to the principles of the present invention to members having specific cross sections.
- While the invention has been disclosed and described with reference with a limited number of embodiments, it will be apparent that variations and modifications may be made thereto without departure from the scope of the invention. Therefore, the following claims are intended to cover all such modifications, variations, and equivalents thereof in accordance with the principles and advantages noted herein.
Claims (9)
1. A bumper constructed of a roll formed metal material, comprising an elongated roll formed bumper member (47) having a predetermined transverse cross section and a longitudinal extent, said predetermined transverse cross section having one at least partially open side, said bumper being characterized in that said longitudinal extent hasa predetermined bumper sweep of about 80 and said metal material having an MPa of at least 827.
2. A bumper as claimed in claim 1 wherein said metal material is a martinsitic steel.
3. A bumper as claimed in claim 2 wherein said metal material is a steel that has a minimum 0.2 percent offset yield strength of about 120,000 psi (827 MPa) and a ferritic grain structure.
4. A bumper as claimed in claim 3 wherein said bumper member has a thickness of less than approximately 2.0 mm.
5. A bumper as claimed in claim 1 wherein said metal material is a quenched and tempered steel having a minimum ultimate tensile strength of about 140,000 psi (965 MPa) and a grain structure comprised of ferrite and tempered martinsite.
6. A bumper as claimed in claim 5 wherein said bumper member has a thickness of less than approximately 2.0 mm.
7. A bumper as claimed in claim 1 wherein said metal material is a quenched and tempered steel having a minimum ultimate tensile strength of from about 190,000 to about 220,000 psi (from about 1310 MPa to about 1516 MPa) and having a tempered martinsite grain structure.
8. A bumper as claimed in claim 7 wherein said bumper member has a thickness within the range of approximately 0.8 mm to approximately 1.6 mm.
9. A bumper as claimed in claim 8 wherein said bumper member has a thickness within the range of approximately 1.0 mm to approximately 1.3 mm.
Priority Applications (1)
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US10/976,417 US20050062299A1 (en) | 2000-01-14 | 2004-10-29 | Sweep forming assembly and method |
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US10/169,994 Division US6820451B2 (en) | 2000-01-14 | 2001-01-08 | Sweep forming assembly and method |
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US20060001294A1 (en) * | 2004-07-01 | 2006-01-05 | Balgaard Steven P | Rocker assembly for vehicles |
US20060028032A1 (en) * | 2004-08-06 | 2006-02-09 | Karl Henseleit | Vehicle bumper and method of making same |
US7665778B2 (en) | 2006-02-02 | 2010-02-23 | Karl Henseleit | Vehicle bumper and method of making same |
US20070176440A1 (en) * | 2006-02-02 | 2007-08-02 | Joseph G. Burgess | Vehicle bumper and method of making same |
CN100379501C (en) * | 2006-07-21 | 2008-04-09 | 吉林大学 | Equipment for flexible rolled plate in 3D curved surface |
US20100011829A1 (en) * | 2006-08-23 | 2010-01-21 | Metform International Ltd. | Roll-forming machine for forming smooth curves in profiled panel sections and method of forming curved panels |
US20090255310A1 (en) * | 2008-04-09 | 2009-10-15 | Heinz Richard D | Multi-directionally swept beam, roll former, and method |
US8307685B2 (en) | 2008-04-09 | 2012-11-13 | Shape Corp. | Multi-directionally swept beam, roll former, and method |
US20110067473A1 (en) * | 2009-09-21 | 2011-03-24 | Heinz Richard D | Method of Forming Three-Dimensional Multi-Plane Beam |
US20110067472A1 (en) * | 2009-09-21 | 2011-03-24 | Heinz Richard D | Roll Former With Three-Dimensional Sweep Unit |
US8333096B2 (en) | 2009-09-21 | 2012-12-18 | Shape Corp. | Method of forming three-dimensional multi-plane beam |
US8333095B2 (en) | 2009-09-21 | 2012-12-18 | Shape Corp. | Roll former with three-dimensional sweep unit |
US8763437B2 (en) | 2009-09-21 | 2014-07-01 | Shape Corp. | Roll former with three-dimensional sweep unit |
US10351175B2 (en) * | 2015-10-01 | 2019-07-16 | Benteler Automobiltechnik Gmbh | Motor vehicle hybrid structural part |
Also Published As
Publication number | Publication date |
---|---|
DE60108239D1 (en) | 2005-02-10 |
ATE286439T1 (en) | 2005-01-15 |
MXPA02006899A (en) | 2004-09-06 |
BR0107477A (en) | 2002-10-08 |
DE60108239T2 (en) | 2006-02-23 |
CA2394138C (en) | 2009-07-21 |
US6820451B2 (en) | 2004-11-23 |
US20030038489A1 (en) | 2003-02-27 |
EP1280620A2 (en) | 2003-02-05 |
CA2394138A1 (en) | 2001-07-19 |
WO2001051228A3 (en) | 2002-10-24 |
WO2001051228A2 (en) | 2001-07-19 |
EP1280620B1 (en) | 2005-01-05 |
AU2001226601A1 (en) | 2001-07-24 |
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