US3621697A

US3621697A - Tube bending tool

Info

Publication number: US3621697A
Application number: US833415A
Authority: US
Inventors: Robert S Martinko
Original assignee: Crawford Fitting Co
Current assignee: Crawford Fitting Co
Priority date: 1969-06-16
Filing date: 1969-06-16
Publication date: 1971-11-23
Anticipated expiration: 1988-11-23

Abstract

DISCLOSED IS A HAND OPERATED TUBE TOOL OF THE TYPE WHEREIN A BEND IS PLACED IN A TUBE BY ROTATING THE TUBE END ABOUT A FORMING ROLL OR MANDREL. THE TUBE BENDING TOOL OF THIS INVENTION IS PROVIDED WITH A FORMING ROLL MEANS HAVING A PLURALITY OF SUBSTANTIALLY CIRCULAR MANDRELS CONCENTRICALLY ARRANGED ON A SHAFT. EACH OF THE MANDRELS HAS A DIAMETER DIFFERENT FROM THE DIAMETER OF THE OTHER OF THE MANDRELS WITH A SUBSTANTIALLY PERIPHERAL GROOVE FORMED IN EACH OF THE MANDRELS. A SECOND SHAFT IS PROVIDED ON THE TOOL WITH A PLURALITY OF IDLER ROLLERS THEREON, EACH ROLLER DISPOSED SUBSTANTIALLY ADJACENT ONE OF THE MANDRELS. A COVER IS ADJUSTABLY CARRIED ON THE TOOL IN SUCH A MANNER AT TO BE ADJUSTED VERTICALLY WHEREBY THE UPPER SURFACE OF THE COVER MAY BE ALIGNED WITH A PARTICULAR MANDREL AND IDLER ROLLER SUCH THAT THE TUBE BENDING TOOL MAY BE USED TO PLACE BENDS IN TUBING OF VARIOUS DIAMETERS WITHOUT THE NECESSITY OF REPLACING THE MANDREL AND THE IDLER ROLLERS.

Description

Nov. 23, 1971 R. s. MARTINKO TUBE BENDING TOOL 2 Sheets-Shoot Filed June 16, 1969 INVFN'I'UR. RQBERTSMARTINKO ATTORNEYS Nov. 23, 1971 R. s. MARTINKO TUBE BENDING TOOL I2 Sheets-Shoot k.

Filed June 16, 1969 INVENTUR. ROBERT S. MARTINKO ATTORNEYS United States Patent W 3,621,697 TUBE BENDING TOOL Robert S. Martinko, Chagrin Falls, Ohio, assignor to Crawford Fitting Company, Solon, Ohio Filed June 16, 1969, Ser. No. 833,415 Int. Cl. B21d 7/02 US. Cl. 72-219 7 Claims ABSTRACT OF THE DISCLOSURE .is provided on the tool with a plurality of idler rollers thereon, each roller disposed substantially adjacent one of the mandrels. A cover is adjustably carried on the tool in such a manner as to be adjusted vertically whereby the upper surface of the cover may be aligned with a particular mandrel and idler roller such that the tube bending tool may be used to place bends in tubing of various diameters without the necessity of replacing the mandrel and the idler rollers.

BACKGROUND OF THE INVENTION This invention relates to a hand operated tube bending tool for the purpose of placing bends in tubing of copper, steel or the like.

Hand operated tube bending tools are well known to the art. As an example of such a tool, reference is made to Pat. No. 3,236,082 to Beck et al. As shown in the Beck et a1. patent, a squared crank arm which carries a hand roller at its outer end is nonrotatably received in the recess of a crank shaft to which is secured a bevel gear. Rotation of the crank arm about the crank shaft axis produces rotation of the bevel gear thereby imparting rotation to a forming roll of the tube bender.

The forming roll itself is provided with an arcuate peripheral groove which terminates at its end in a flat section or length. A tube clamp bar extends from the forming roll and is provided with an arcuately shaped tube clamping jaw. The tube clamp bar also carries a tube stop. A U-frame support member is secured to the tube bending tool and is provided with a pair of tube idler rollers. A peripheral groove is formed in each of the rollers and is of the same shape and depth as the groove of the forming roll. As illustrated in FIGS. '2 and 3 of Beck et al. Pat. No. 3,236,082, the tube is fully enclosed within the peripheral complementary grooves of the forming roll and the idler roller 54 at the plane of contact of these members.

As illustrated in FIG. 2 of the Beck et al. Pat. No. 3,236,082, rotation of the crank arm 21 imparts rotation to the forming roll 28 and accordingly to the bar member 42. The tube having been secured to the bar 42 is thereupon bent about the axis of the forming roll.

3,621,697 Patented Nov. 23, 1971 The crank is rotated until the tube stop means 44 abuts the pointer stop member 38. At this juncture, a bend of predetermined angularity will have been produced in the tube. The spring-loaded plunger 58 is next lifted to free the frame 52 for outward swinging movement of the idler roller 54. After the clamping jaw 43 has been swung free of engagement with the tube, the tube may be withdrawn from the tool.

A shortcoming in prior art tube bending tools such as that shown in the Beck et al. Pat. No. 3,236,082 is that the tool can accommodate a tube diameter of only one size. Thus, with a peripheral groove formed in each of the rollers of the same shape and depth as the peripheral groove formed in the forming roll, the tube bending tool can only accommodate tubing having an outside surface complementary to the respective grooves. It is not possible to place bends in tubing of various diameters in the absence of a complete substitution of the forming roll and the idler rollers.

This invention contemplates a tube bending tool wherein the forming roll means comprises a plurality of substantially circular mandrels arranged longitudinally and concentrically on the shaft of the tube bending tool. Each of the mandrels has a diameter different from the diameter of the other of the mandrels with a substantially peripheral groove formed in each of the mandrels. Idler roller sets are provided in addition to the mandrels. Each roller of the sets is provided with a peripheral groove. A vertical adjustable cover is carried by the tool in such a manner that support may be provided for the tubing as a particular mandrel is used to accommodate a particular diameter of tubing.

The preferred embodiment of this invention contemplates the use of three substantially circular mandrels thus providing a tube bending capability for tubes of three diiferent diameters,

BRIEF SUMMARY OF THE INVENTION Briefly summarized, this invention relates to improvements in hand operated tube bending tools and more particularly relates to an improved design of tube bending tools wherein a forming roll or mandrel is utilized in order to place a bend in tubing as by securing the tube end to an extension of the forming roll or mandrel and thereafter bending the tube about the forming roll or mandrel.

The tube bending tool comprises a base with a cover supported thereon and including a shaft rotatably supported by the cover and the base of the tool. Manual drive means are rotatably supported on the base with means interconnecting the drive means with the shaft whereby rotation of the drive means causes a corresponding rotation of the shaft. Forming roll or mandrel means are carried by the end of the shaft for rotation therewith. The forming roll means comprises a plurality of substantially circular mandrels arranged longitudinally and concentrically on the shaft. Each of the mandrels has a diameter different from the diameter of the other of said mandrels with a substantially peripheral groove formed in each of the mandrels. A second shaft is supported on the base with a plurality of idler rollers disposed thereon. Each of the idler rollers is positioned adjacent one of the mandrels. A peripheral groove is formed on each of the rollers. A second set of idler rollers is also employed in the tube bending tool, said second set of rollers being spaced from both the first set and the mandrels.

A threaded bore is provided in each of the mandrels with an elongated bar adapted to be received therein. A tube abutment means is carried on the bar and a stop member is carried on the base of the tool to cooperate with the bar thereby to control the degree of bend placed in the tube.

A cover is adjustably carried on the base in such a manner that the cover may be adjusted vertically of the base whereby the upper surface of the cover may be aligned with the particular mandrel then in use to provide support for the tube.

BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWINGS The features of this invention will become more apparent upon a complete review of the following description and a perusal of the accompanying drawings in which:

FIG. 1 is a top plan view of the tube bending tool of this invention in an operating position;

FIG. 2 is a vertical sectional view taken along the line 22 of FIG. 1;

FIG. 3 is a detailed vertical sectional view taken along the line 33 of FIG. 1;

FIG. 4 is a view taken along the line 4-4 of FIG. 1; and

FIG. 5 is a view illustrating the design of the adjustable cover.

DESCRIPTION OF THE PREFERRED EMBODIMENT Referring to the drawings and more particularly to FIGS. 1 and 2, the tube bending tool of this invention comprises a cup-shaped base 11 and a base plate 12 secured to base 11 by socket head cap screws 13 or the like. The base 11 has depending from its bottom centrally thereof a block 14 with flat faces 15 suitable for applying the jaws of a vise for holding the tool on a bench or preferably on a single column to provide space for compound angle bending. The base 11 and the base plate 12 define an annular space 16 for housing the

bevel gears

17 and 18. Bevel gear 17 is fixed to the inner end of a crank shaft 19 by suitable means such as pin 20 with the shaft 19 being journaled in the side wall of the base 11. The outer end of the crank shaft 19 is axially recessed for removably receiving the free end of a square crank arm 21 which carries a hand grasp roller 22 at its outer end. Bevel gear 18 is rotatably supported by a shaft 23 having its lower end journaled in the bottom of the base member 11 as indicated at 24. Gear 18 is secured to shaft 23 by suitable means such as a key 25.

A cover, indicated generally at 30, is received over the base 11 and the base plate 12 with the shaft 23 extending through and above the cover. The function of cover 30 will be described more fully hereafter.

Secured to the end of the shaft 23 by means of key 25 is a forming roll means indicated generally at 26. The forming roll means comprises a plurality of substantially

circular mandrels

27, 28 and 29. Each of the mandrels has a diameter different from the diameter of the other of the mandrels. Each of the mandrels has a substantially peripheral groove or circumferential

concave surface

32, 33 and 34 respectively. A flat, such as the flat 35 on the mandrel 27, is formed on each of the mandrels with a threaded radial bore 36 also being formed in each of the mandrels.

Adapted to be received in the threaded bore 36 is the threaded end of a radius bar 37. An adjustable tube stop 38 is clamped to the bar by thumb screw 39. A centering tip 40 adapted to be received in the end of a piece of tubing is carried by the tube stop 38.

The base plate 12 supports a U-frame member 42 which carries a plurality of sets of

idler rollers

43, 44. The one set of rollers 43 comprises rollers 43a, 43b, 43c,

4 all of which are journaled on a bolt 45 threaded to the base plate 12. The bolt 45 also serves for pivotally securing the end of the frame member 42 to the base plate 12 as is shown more clearly in FIG. 1.

The other set of rollers 44 comprises rollers 44a, 44b, 440, all of which are supported rotatably by a sleeve 46. The sleeve 46 encloses a spring-loaded plunger 47 adapted to seat in a sleeve lined bore 48 in the base plate 12. The plunger head 49 threaded on the outer end of the plunger 47 serves for manually releasing the set of rollers from their operative position while permitting the frame member 42 to be swung to the position illustrated in dotted lines in FIG. 1.

Each of the rollers in the sets of

rollers

43, 44 has a diameter complementary to the diameter of one of the

mandrels

27, 28, 29. As will be seen in FIG. 2, the larger diameter mandrel 27 corresponds with the smaller diameter roller 440. There is a similar relationship with respect to

mandrels

28, 29 and rollers 44b, 44a. Each roller also includes a peripheral groove which is substantially the same in shape and depth as the groove in the mandrel in the same horizontal plane as the roller. As illustrated in FIG. 2, the set of rollers 44 and the

mandrels

27, 28, 29 are juxtaposed such that the combination of the grooves in the mandrels and the grooves in the rollers define substantially circular openings of varying diameters at the line of contact of the rollers and the mandrels.

The inner end of the bar 37 is reduced adjacent the flat section on the mandrels for pivotally supporting an arcuately shaped tube clamping member 51 (FIG. 3). A separate tube clamping member is provided for each of the mandrels.

The adjustable cover 30 has indicia scribed on the uppel surface thereof which denotes various degrees of angle bends. A pointer 52 is adjustably carried by the base and is positioned over the cover so that the degree of desired bend may be indicated. The pointer includes an upstanding arm 53 which is adapted to engage the bar 37 thereby to limit the degree of bend placed in the tubing. The pointer 52 is adjustably supported by a bolt 54 which has its inner end adapted to engage the walls of groove 55 formed in the periphery of the base 11. The outer end of the bolt 54 comprises an adjustable knurled nut 56 which is employed to position the pointer in the desired location.

The cover 30 is adjustably carried by the base so that it may be positioned vertically to correspond with the particular one of the mandrels then in use. The cover is supported on the base as by means of clamping screws 60 (FIG. 1) which are received in slots 61 (FIG. 5) defined in the cover. Clamping screws 60 extend through slots 61 and are adapted to be received in suitable threaded bores (not shown) in the base 11. The cover 30 further includes a slot 62 (FIG. 5) extending around a portion of the periphery of the cover to accommodate the positioning of the pointer 52. It should be noted that the pointer 52 is not only adjustable circumferentially about a portion of the periphery of cover 30 but is also adjustable vertically relative to the base. This vertical adjustment is accommodated by means of slot 63 (FIG. 2) defined in the pointer.

An opening 64 is provided in the upper surface of the cover 30 to accommodate the idler rollers and the mandrels as the cover is adjusted vertically. Similarly, an opening 70 (FIG. 2) is provided in the side Wall of the cover to accommodate the protruding crank shaft 19.

Thus, by loosening of the clamping screws 60 the cover 30 may be adjusted vertically permitting a work surface to be provided adjacent each of the three mandrels thus to provide support for the tubing.

OPERATION OF THE TUBE BENDING TOOL A brief description of the operation of the tube bending tool of this invention will now be made with reference to FIGS. 1-3.

Assuming it is desired to place a bend in a tube having an exterior surface complementary to the peripheral groove of mandrel 27 (FIG. 2), the radius bar 37 is positioned in place as by threadedly advancing the bar into the threaded bore 36 of mandrel 27 as shown in FIG. 2. The adjustable cover 30 is thereafter moved to its lowermost position as shown in FIG. 2 in order to provide support for the tubing as it is bent by the mandrel 27.

The plunger 47 is operated to free the frame 42 on its bolt 45 and the frame is pivoted thereabout to the outward position shown in dotted lines in FIG. 1. The crank arm 21 is operated to bring the mandrel 27 into position for placing the tube stop 38 carried by bar 37 at zero point on the scale of the adjustable cover 30. The tube is then positioned in the groove 32 of mandrel 27 with the leading end of the tube being brought past the idler roller 43c and mandrel 27 a sufiicient degree so that it will be held in the groove 32 of the mandrel 27 upon engagement by the arcuate tube clamping member 51 with centering tip 40 received in the tube end. The frame 42 is swung inwardly about its pivot at bolt 45 until the spring-loaded plunger 47 seats itself in the sleeve lined bore 48 in the base plate 12. At this junction the roller 44c is brought into operating relation with the mandrel 27, i.e. the mandrel and associated roller fully surround and support the tube wall as shown in FIG. 2.

The pointer 52 is set for the angle the tube is to be bent. For example, if a 90 angle is desired, the position of the pointer would be that as shown in FIG. 1. With the positioning of roller 440, the roller 430 also is in position for a tube bending operation.

The crank arm 21 is then rotated, rotating bevel gear 17, thereby imparting rotation to bevel gear 18. The mandrel 27 and bevel gear 18 are attached to the shaft 23 so that rotation thereof imparts rotation to the radius bar 37 and tube stop 38, thus rotating the tube carried by the centering tip 40 to impart a bending motion thereto. The crank arm 21 is rotated until the radius bar 37 abuts the pointer 52 as best seen in FIG. 1. At this point a 90 bend will be produced in the end of the tube. The springloaded plunger 47 is next lifted to free the frame 42 for outward swinging movement of the roller 440. After the tube clamping member 51 has been swung free of engagement with the tube end, the tube may be easily withdrawn from the tool.

In the event that it is desired to place a bend in a piece of tubing having a smaller diameter than that accommodated by the mandrel 27, either of the

mandrels

28 or 29 may be selected. Presuming that mandrel 29 (having an arcuate groove 34) is suitable for a particular piece of tubing, the tube bending tool of this invention may be quickly adjusted to accommodate the smaller diameter tubing.

To accomplish such an adjustment, the radius bar 37 is first removed from the threaded bore 36 of mandrel 27 and reinserted into a similar threaded bore 36 of mandrel 29. Thereafter, adjustable cover 30 is raised to its uppermost position as by loosening clamping screws 60 (FIG. 1) and raising the cover to a position immediately adjacent the bottommost surface of mandrel 29. Naturally, prior to raising the adjustable cover a vertical adjustment is made in the pointer 52 as by loosening the knurled nut 56. Such an adjustment is shown in dotted lines in FIG. 5. After positioning, the pointer and the adjustable cover are secured in place as by tightening of the clamping screws 60 and the knurled nut 56. The smaller diameter tubing may now be bent using the procedures outlined above.

MODIFICATIONS OF THE INVENTION Modifications of the preferred embodiment of this invention are complated and should be considered within the scope of the invention.

While in the preferred embodiment of the invention support for the tubing is provided by means of an adjustable cover 30, the same support function could be achieved by providing a vertical adjustment for the multiple mandrels themselves. Thus, an arrangement might be employed in which the cover 30 is fixed to the base with the mandrels being shifted vertically so as to dispose a particular desired mandrel adjacent the upper surface of the fixed cover. Similar vertical adjustment could be provided for the sets of

rollers

43, 44.

It is thus to be understood that the tube bending tool of this invention is not dependent for its operation on the adjustability of either the cover and or the mandrels.

The invention claimed is:

1. A tube bending tool comprising:

a base;

forming roll means carried by said base;

said forming roll means having an axis and comprising a plurality of substantially circular mandrels of varying diameters arranged in substantially side-by-side relation;

a substantially peripheral groove formed in each of said mandrels;

means to turn a tube about said forming roll means;

cover means having an upper surface and adjustably attached to said base and adapted to be moved toward and away from said base in a direction parallel to the axis of said forming roll means whereby said upper surface of said cover means may be positioned in substantially the same horizonal plane as a selected one of said mandrels.

2. The invention of claim 1 and further including a radially extending bore formed in each of said mandrels with each bore being of substantially equal diameter and in vertical alignment with every other bore;

a bar adapted to be received in each of said bores;

said bar including abutment means adapted to abut the end of a tube;

manual drive means providing for rotation of said bar.

3. The invention of claim 2 and further including stop means adapted to engage said bar;

means supporting said stop means on said base for permitting circumferential adjustment of said stop means relative to said base.

4. The invention of claim 1 and further including tube supporting means comprising:

a shaft supported on said base;

a plurality of idler rollers on said shaft with each of said rollers being disposed adjacent one of said mandrels;

a peripheral groove formed in each of said rollers.

5. The invention of claim 4 and further including means adjustably supporting said shaft on said base whereby said idler rollers may be moved toward and away from said mandrels.

6. The invention of claim 1 and further including a shaft supported on said base and spaced from said forming roll means;

a first set of idler rollers spaced along said shaft;

frame means carried by said shaft;

a second set of idler rollers supported on said frame means;

each of the idler rollers in said sets of idler rollers including a peripheral groove formed therein;

the number of rollers in each of said sets of rollers being at least equal to the number of mandrels of said forming roll means, with each of the respective idler rollers being in the same horizontal plane as a respective mandrel;

the peripheral groove in each particular idler roller being substantially the same in shape and depth as the groove in the mandrel that is in the same horizontal plane as the particular idler roller.

7. The invention of claim 1 in the which said cover means is defined as a generally cupshaped element having an upper surface and side walls and including adjustable clamping means for securing said side Walls to said base.

References Cited UNITED STATES PATENTS Reynolds 72-2l7 Parker 72-157 Perkins 721S9 Morton 72217 Miller 72159 Beck et al. 72149 8 FOREIGN PATENTS 5 8,248 1/ 1912 Switzerland 72-219 945,203 7/1956 Germany 72--157 5 CHARLES W. LANHAM, Primary Examiner M. J. KEENAN, Assistant Examiner US. Cl. X.R.