US3018818A - Pipe bender - Google Patents

Description

Jan. 30, 1962 E. c. SWANSON PIPE BENDER 2 Sheets-Sheet 1 Filed Feb. 27, 1957 IVENTOR.

Jan. 30, 1962 E. c. SWANSON PIPE BENDER 2 Sheets-Sheet 2 Filed Feb. 27, 1957 ilnited States Patent 9 3,018,818 PlPE BENDER Edwin C. Swanson, Rockford, Ill., assignor to Greenlee Bros. & Co., a corporation of Illinois Filed Feb. 27, 1957, Ser. No. 642,839 8 Claims. (Cl. 153-48) This invention relates to pipe benders, and particularly to pipe benders of the type having a pair of spaced pipe engaging rollers, a force applying ram reciprocable toward and away from a midpoint between the rollers, and a pipe bending shoe structure connected to the ram for producing a bend in the mid-section of a length of pipe positioned against the rollers.

It is a general object of the invention to provide a new and improved pipe bender of the type described.

It is a more specific object of the invention to provide a new and improved pipe bending shoe structure for use in a bender of the type described.

Another object is to provide a new and improved bending shoe structure of the character described, including an adapter connected to the ram, and a bending shoe detachably connected to the adapter in a manner such that ram forces are distributed over a substantial length of the bending shoe so that a number of different size bending shoes may be constructed of relatively lightweight material, as compared to the material of the adapter, for use with the adapter, thereby providing a readily portable and versatile bending apparatus.

It is also an object of the invention to provide a new and improved pipe bender of the type described having indicia provided thereon for use in determining when the desired degree of pipe bend has been produced.

Another object is to provide, in a bending shoe structure, new and improved means for dislodging the pipe from the shoe after bending. 1

A further object is to provide, in a bender of the type described, a new and improved mounting pin assembly for mounting the pipe-engaging rollers to be readily removable and replaceable. I

Other objects and advantages will become readily apparent from the following detailed description taken in connection with the accompanying drawings, in which:

FIG. 1 isa plan view of a pipe bender embodying the principles of the present invention, with a portion of the top frame plate broken away to better illustrate the bending shoe structure;

FIG. 2 is a longitudinal sectional view of the bender illustrated in FIG. 1, taken at about the line 2-2 of FIG. 1;

FIG. 3 is a front elevational view of the bender illustrated in FIGS. 1 and 2;

FIG. 4 is an enlarged plan view illustrating in detail the construction of the adapter forming a part of the bending shoe structure included in the bender of FIGS. 1, 2 and 3;

FIG. 5 is a front elevational view of the adapted illustrated in FIG. 4;

FIG. 6 is an end elevational view of the adapter illustrated in FIGS. 4 and 5, also showing in section the bending shoe illustrated in FIG. 1, the section through the bending shoe being taken at about the line 6-6 of FIG. 1;

FIG. 7 is an enlarged front elevational view of the bending shoe;

FIG. 8 is an enlarged sectional view, taken at about the line 88 of FIG. 1, illustrating the pin mounting assembly for mounting the pipe engaging rollers utilized in the bender illustrated in FIGS. 1, 2, and 3;

FIG. 9 is a bottom plan view of the pin mounting 3,5a18,818 Patented Jan. 30, 1962 assembly illustrated in FIG. 8, taken at about line 9-9 of FIG. 8; and

FIG. 10 is an enlarged sectional view through the bending shoe, taken at about the line 10-40 of FIG. 1, illustrating details of the means provided for removing pipe from the bending shoe after bending.

While an illustrative embodiment of the invention is shown in the drawings, and will be described in detail herein, the invention is susceptible of embodiment in many different forms, and it should be understood that the present disclosure is to be considered as an exemplification of the principles of the invention and is not intended to limit the invention to the embodiment illustrated. The scope of the invention will be pointed out in the appended claims.

Referring'now to the drawings, and particularly to FIGS. 1,2, and 3, for a detailed description, as illustrated, the invention is embodied in a pipe bender including a pair of frame plates 10 and 11 of generally triangular shape mounted in overlying spaced apart relationship in order to receive therebetween a length of pipe to be bent. A pair of pipe-engaging rollers 12, similarly formed, are mounted in spaced apart relationship between the plates '10 and 11, with the roller axes extending in a direction normal to the planes of the plates. The frame plates 10 and 11 support a ram device, generally designated 13, including a force applying ram reciprocable between the plates toward and away from a midpoint between the pipe engaging rollers 12. A pipe bending shoe structure, generally designated 14, is attached to the force applying ram and includes a pipe engaging portion effective to produce a bend in the mid-section of a length of pipe positioned between the frame plates against the pipe-engaging rollers.

As illustrated, the frame plates 10 and 11 are of generally triangular shape and are rigidly held in overlying, spaced-apart relationship by means of a pair of spacers 16 (FIG. 3), which are positioned between the plates adjacent the ram device 13 and to which the plates are secured by means such as screws 17.

The pipe-engaging rollers 12 are similarly formed and each may be recessed on its periphery, arcuately, to receive a portion of the outer circumference of a length of pipe to be positioned thereagainst. As illustrated, each of the rollers 12 includes, at angular spaced positions thereon, four arcuate recesses 19, 20, 21 and 22 (FIGS. 2, and 3) of different radii, so that by angularly positioning the rollers, they are adapted for receiving pipes of different sizes.

The pipe engaging rollers 12 are mounted between the frame plates by means of roller pin mounting assemblies 24 (FIGS. 8 and 9) which serve to rotatably 4 support the rollers and which are readily removable and replaceable in order to permit quick removal of the rollers 12 and ready substitution therefor of rollers having differently formed pipe receiving recesses. As illustrated in FIG. 8, the pipe-engaging rollers are each formed with a central axial bore 25, and the pin mounting assembly 24 includes a main pin body 26 of cylindn'cal shape receivable in the bore 25 so that the roller is rotatable on the pin body. As seen in FIGS. 1 and 8, the frame plate 10 is formed with a plurality of pairs of circular apertures 27, 28, 29, 30, etc. of a diameter similar to the roller bore 25 and also for receiving the pin bodies are mounted one in each of the apertures 27, or one in each of the apertures 28, etc. The different pairs of apertures 27, 28, etc. are provided for repositioning the pipe-engaging rollers to accommodate pipe lengths of different size diameters. For example, the apertures 27 may be utilized to position the pipe-em gaging rollers for bending a pipe of 4" diameter, the apertures 28 for pipe of 3 diameter, and so on. The degree of bend produced in the pipe is normally determined by the length of the ram stroke; and the radius of bend produced in the pipe is normally determined by the curvature of the pipe engaging face of the bending shoe.

Referring again to FIG. 8, the upper end of the pin body 26 is enlarged as illustrated at 33 to form an annular shoulder or abutment 34 engageable with the top of the upper frame plate to limit movement of the pin body through the plates and through the pipe-engaging rollers. Once positioned, the pin body 26 may be locked in place by means including a locking shaft 35 rotatable in an axial bore 36 eccentrically positioned in the pin body 26 and extending throughout the length thereof. Near its lower end, the locking shaft 35 is provided with an integral, radially projecting locking lug 37. The locking lug 37 is movable in a recess 37a extending transversely across the pin body a distance slightly more than half the diameter of the pin body. As illustrated in FIGS. 8 and 9, the locking lug 37 is of a length such that in one angular position of the locking shaft 35 (the broken line position of FIG. 9) the lug does not project beyond the periphery of the pin body 26 and, therefore, permits movement of the pin body through the apertures in the frame plates and through the roller bores. In a diametrically opposite angular position of the locking shaft 35, the lug 37 projects outwardly beyond the periphery of the pin body 26 (the full line positions of FIGS. 8 and 9). In the. latter position of the locking lug, it serves to engage the bottom surface of the lower frame plate 11 in opposition to the shoulder 34 to thereby prevent removal of the pin body 26.

In order to facilitate manual operation of the locking shaft 35, it is provided at its upper end with a radially projecting handle 40. Cooperating means may be provided on the handle 40 and the pin body 26 for retaining the locking shaft 35 in locking position. The retaining means may take the form of a spring pressed ball 41 engageable with a dimple formed in the under side of the handle 40.

Referring again to FIGS. 1, 2 and 3, the ram device 13 includes a fluid cylinder 45 having a hollow elongated piston or ram 46 reciprocable therein. The cylinder 45 is supported by means of a cylinder block 47 secured to one end of the cylinder and positioned between the mounting plates 10 and 11. The cylinder block is secured in place between the plates 10 and 11 by means such as the pins illustrated at 48, which pass through the plates 10 and Ill and through complementary bores in the cylinder block. The pins 48 also register with an outer annular groove 45a (FIGS. 1 and 2) formed on the cylinder 45 to retain the cylinder in the block.

The cylinder 45 is closed at its end away from the cylinder block 47, and fluid may be admitted to this end of the cylinder through an inlet fitting 49. Fluid, preferably air, under pressure, may be supplied to the inlet fitting 49 and the interior of the cylinder 45 by means of a hand operated pump, or by other means if desired. The opposite end of the cylinder 45 is open, and the elongated piston or ram 46 projects from the open end of the cylinder for connection with the bending shoe structure 14 previously referred to and described in detail hereinafter. The ram 46 is biased toward a retracted position in the cylinder 45 by means of a tension spring 50. The spring 50 is connected to the cylinder 45 at its closed end by means-of a spring retaining nut 51 threaded into the spring and threaded onto a spring retaining screw 52 which is in turn threaded into the cylinder end 45b. The spring 50 is connected in a similar manner at its opposite end to the closed end of the ram 46 by means of a spring retaining nut 53 threaded into the spring and threaded onto a spring retaining screw 54 which is in turn threaded into the piston end cap 46a. It will be celar that on the admission of fluid under pressure to the interior of the cylinder 45 and the interior of the ram 46, the ram will be extended against the bias of the spring 50, and that on exhaust of fluid, the spring 50 will serve to retract the ram.

The bending shoe structure 14 is detachably connected to the force applying ram, and is formed of a two-piece construction including an adapter 57 and a ending shoe 58. In pipe benders of the character described, ram forces are applied to a localized area of the bending shoe structure, and must be transmitted to a relatively elongated pipe engaging face of the bending shot structure. Thus, considerable difiiculty is encountered in constructing the bending shoe structure in a manner to provide sufiicient strength for receiving the localized ram forces and distributing these forces over the length of the pipe-engaging face while at the same time providing a practical structure economical to manufacture and sufficiently light to permit portability of the pipe bender as well as portability of the pipe bending shoc structures which must be provided in different sizes and shapes for accommodating different pipes and for producing different bends.

According to the present invention, the difliculties alluded to are overcome by the provision of the two-piece bending shoe structure referred to. As illustrated, the adapter 57 is formed generally in the shape of a circular segment (FIG. 4) having a chordal side 59 for receiving the ram forces, and an arcuate side 60 for transmitting the ram forces to the bending shoe 58. The bending shoe 58 is formed generally in the shape of an arcuate segment (FIG. 1), having an arcuately curved pipe-engaging face 61, and an oppositely disposed face 62 for receiving the ram forces transmitted by the adapter 57. The interengaging faces 60 and 62 of the adapter and the bending shoe are relatively elongated as compared to the engaging surfaces of the ram and adapter so as to distribute the ram forces transmited to the adapter over a substantial length of the pipe bending shoe. An advantage of the construction illustrated lies in the fact that the adapter, connected to the ram, may be constructed of a relatively heavy, high strength material which will withstand the stresses set up in transmission of the ram forces to the bending shoe, while the bending shoe 58 and similar shoes of different sizes and shapes, may be readily detachable from the adapter and constructed of a relatively lightweight material, thereby rendering the pipe bender and the pipe bending shoes readily portable for movement from place to place. In the construction illustrated, the adapter may be constructed of material such as steel, and the bending shoes may be constructed of materials such as aluminum or magnesium.

Referring now particularly to FIGS. 4, 5 and 6 for a detailed description of the adapter, it is of somewhat hollow frame-like construction. Centrally on its chordal side 59, the adapter is formed with a recess in the form of a bore 64 which provides a socket for receiving the projecting end of the force applying ram 46. The bore 64 terminates in the adapter, providing a bottom or force receiving surface 65 engageable with the end cap 46a of the ram for transmitting the ram forces to the adapter.

In order to detachably connect the adapter to the ram, the ram is provided with an outer circumferential groove 66 (FIG. 2), and the adapter is provided with a pair of bores 67 and 68 (FIG. 4) transverse to the bore 64 and substantially tangential thereto on opposite sides thereof, for receiving pins such as that illustrated at 69 (FIG. 1).

on the adapter.

faces 83a and 83b (FIG. 7).

The pins, when positioned in the bores 67 and 68, are

adapted to intersect with and be received in the annular groove 66 in the ram so as to detachably connect the ram and adapter. Access may be had to the pins 69 for attaching the adapter to the ram through an aperture 79 formed in the upper frame plate It It should be understood that the connection aiforded by the pins 69 is provided principally for use in retracting the bending shoe structure under influence of the spring 50. The bending shoe structure, including the adapter, is forced outwardly to bend the pipe principally by engagement of the end cap 46a on the ram with the force receiving surface 65 It will be seen that the force of the ram is applied to the adapter over a relatively localized area.

In order to transmit the ram forces from the adapter .to the bending shoe, and in order to permit detachable connection of the bending shoe with the adapter, the

arcuate side 69 of the adapter is recessed throughout its length, to leave spaced forwardly projecting web portions 71 and 72 (FIG. 6) which are arcuately curved in plan view (FIG. 4). The forwardly facing, arcuately curved surfaces 71 and 72' on the web portions 71 and 72 form the force transmittingsurfaces of the adapter, and are engageable with force receiving surfaces of the bending shoe.

In order to provide a close fit of the bending shoe with the adapter so as to eliminate relative movement between the two when connected, the inner surfaces of each of the web portions 71 and 72 are each formed with three separated lands 71a, 71b, 71c, 72a, 72b, and 720. These lands are raised relative to the adjacent surfaces of the web portions 71 and 72 and are machined so that the bending shoe may be closely fitted between the lands on the web 71 and the lands on the web 72' as illustrated in FIG. 6.

By virtue of the hollow frame-like construction of the adapter, even though it may be constructed of relatively heavy, high strength material, its weight is reduced because of the hollow construction. In order to reinforce the adapter, it is formed on its upper side with laterally spaced, upwardly and rearwardly projecting reinforcing webs 74- and 75 which are integral with the adapter and extend rearwardly from the line of engagement of the ram with the adapter. The underside of the adapter is formed with similar reinforcing webs 76 and 77.

Referring now particularly to FIGS. 1, 6 and 7 for a detailed description of the bending shoe 58, the face 62 of the bending shoe adjacent the adapter is formed centrally with arcuate force receiving surfaces adapted for engagement with the force transmitting surfaces 71' and 72 of the adapter. In order to form the force receiving surfaces on the bending shoe, the shoe is formed with a rearwardly projecting web 81 (FIG. 1) in the form of a circular segment adapted to project into the recess 70 formed in the adapter and terminating in a chordal side 82. The major portion of the web 81 is of a minor thickness substantially thinner than the thickness of the recess 70, as best illustrated in- FIGS. 6 and 7. However, adjacent its projection from the bending shoe proper, the thickness of the web 81 is increased so as to just fit between the lands on the two web portions 71 and 72 of the adapter. The thickened portion, designated 83 is genformed to provide upwardly and downwardly facing sur- The upper surface 83a engages the lands 72a and 720 on the upper web 72 of the adapter, and the downwardly facing surface 83b engages the lands 71a and 710 of the lower web 71 of the adapter. Centrally, the thickened portion 83 includes a rearwardly projectipg lug 85 of a thickness also equal to the spacing between the lands on the upper and lower webs of the adapter, and positioned so as to fit between t the lands 71b and 7219.

In this manner, the bending shoe is positioned between thew'eb-s of the adapter in a erally arcuately shaped as best seen in FIG. 1 and is j b manner to prevent twisting movement of the bending shoe relative to the adapter.

The thickened portion 83 of the Web 81 forms the arcuate side of the web and is joined integrally to the shoe proper in a manner forming shoulders which provide vertically disposed upper and lower surfaces 86 and 87, arcuately curved in plan view as seen in FIG. 1, and adapted for engagement respectively with the force transmitting surfaces 71 and 72' of the adapters. The surfaces 86 and 87 thus form the force receiving surfaces of the bending shoe. It will be appreciated that these surfaces are materially elongated relative to the localized inter-engaging force transmitting surfaces of the ram and adapter. Thus, the ram forces are distributed evenly over a substantial portion of the bending shoe.

In order to detachably connect the bending shoe to the adapter, the central rearwardly projecting lug on the bending shoeis formed with a vertical bore 89 (FIG. 6)

adapted to receive a connector pin. The overlying and 'to the pin 92 for connecting and disconnecting the bending shoe through the access opening 79 in the upper frame plate 10. i

As best illustrated in FIG. 1, the pipe-engaging face 61 of the bending shoe 58 is arcuately curved to produce a desired radius of bend in a length of pipe to be bent. Also, the pipe-engaging face of the bending shoe is recessed transversely throughout its length, arcuately, substantially semi-circularly, for receiving approximately half of the outer periphery of the pipe to be bent, as illustrated at 93, particularly in FIGS. 3 and 6.

In operation, a bending shoe of suitable proportions is selected and attached to the adapter. A length of pipe to be bent is then positioned between the upper and lower frame plates 10 and 11, against suitably recessed pipeengaging rollers 12. Fluid under pressure is then admitted to the ram cylinder, by means of a suitable handoperated air pump, or other means, to advance the bending shoe structure, the bending shoe 58 engaging the midsection of the length of pipe to produce the desired bend between the pipe-engaging rollers, in accordance with the curvature of the bending shoe.

In order to assist the operator in determining when the desired degree of bend has been produced, the bender is provided with indicia means associated with the upper frame plate 10 for indicating in degrees certain angles relative to a reference point and a reference line both having a predetermined relationship to a length of pipe in the bender. The angles referred to are representative of selected degrees of pipe bend. The indicia means referred to includes means defining on the upper surface of the frame plate 10 a point aligned with the path of ram movement. As illustrated, the point is defined by an upright pin a4 secured to the frame plate 10 and positioned in line with the axis of the ram, as seen in FIG. 1. Further, the upper surface of the frame plate 10 is provided with radially disposed indicia 94a, emanating from the point defined by pin 94, angularly spaced about the point, and angularly spaced from an imaginary line passing through the point and normal to the path of ram movement.

The imaginary line passing through pins 94 and normal to the path of ram movement is parallel to the axis of a straight length of pipe positioned in the bender against pipe engaging rollers 12 before bending. After a length of pipe has been bent, it includes opposite end portions, normally of a length to project outwardly beyond the frame plates 10 and 11, one each between a roller 12 and the ram structure 13 (FIG. 1). These end portions are larly spaced from the original axis of the pipe by an amount which, in degrees, is one half the total degree of bend in the pipe. That is, if a bend of 60 is produced in the pipe, each of the opposite end portions of the pipe is angularly spaced by 30 from the original axis of the pipe.

The radially disposed indicia 94a are positioned on the Side of said imaginary line toward the ram device 14, and separate groups of the markings 94a are provided on pposite sides of the path of ram movement. The indicia 94a are identified by degree markings, for example, 15, 30, 45, 60, and 90, as illustrated, which indicate in degrees twice the angular spacing of the particular point 94a from the imaginary line passing through pin 94 and normal to the path of ram movement. That is, the point 94a which is marked 60, is only 30 from the imaginary line. Thus, a line passing through pin 94 and the mark 94a identified as 60 would be parallel to one tangent end portion of a length of pipe having a 60 bend. The indicia provided enables an operator to sight along this line by, for example, laying a 6' rule from the pin 94 to the 60 mark, and compare this line visually with the tangent end portion of the bent pipe to determine if the two appear to be parallel. Thus, the indicia provides a scale which enables an operator to readily determine roughly when the desired degree of bend is produced, without the necessity of removing the pipe from the bender for measurement by other means. This provides a great saving in time where only approximate accuracy of bend is required.

The length of ram stroke is conveniently indicated by an elongated, graduated scale 95 (FIGS. 1 and 3) secured at one end, as by means of a pin 96, to the adapter and movable with the ram and adapter relative to a reference point on the frame plate 10. After one length of pipe has been bent as desired, sometimes by trial and error methods, and the proper length of ram stroke thereby determined for a particular bend, similar successive bends may be produced simply by reference to the scale on subsequent ram strokes. The scale permits the operator to return the ram and bending shoe to the desired position on each operation, to accurately produce the desired bend, without the necessity of relying on trial and error methods.

The pipe engaging face of the bending shoe 58 is recessed at 93 to receive a substantial portion of the outer periphery of the pipe in order to resist the tendency of the pipe to be deformed out of round during the bending operation. However, due to the tendency of the pipe to deform during the bending, the pipe becomes tightly wedged in the bending shoe, so that after the bending operation is completed, considerable difiiculty may be encountered in removing the length of pipe from the bending shoe.

In order to provide for removal of the pipe from the bending shoe after bending, the bending shoe is provided with bores adapted to receive knock-out pins for dislodging the pipe. As illustrated, the bending shoe is formed with a pair of bores 97 and 93 (FIG. 1) spaced respectively approximately one-fourth of the length of the bending shoe from its opposite ends. The bores 97 and 98 extend transversely through the bending shoe, intersecting the semi-circular recess 93 for the pipe, the axis of the bores being substantially tangent to the pipe recess at its bottom, as illustrated particularly in FIG. 10. While the sectional view of FIG. illustrates in detail the pipe removal means associated with the bore 97, it should be understood that the removal means associated with the bore 98 is similar in all respects. As seen in FIG. 10, the bore 97 is preferably fitted with a tubular hardened metal insert 99 which is recessed as illustrated at 100 at the intersection of the insert with the pipe recess 93 in the bending shoe. The tubular insert 99 is adapted to receive a knock-out pin, generally designated 101 having a tapered end portion 102 adapted for engagement with the outer surface of the pipe P in the pipe recess. The tapered surface of the knock-out pin engages the pipe substantially tangentially, and on striking the knock-out pin to deliver an impact blow, as by means of a hand hammer, the knock-out pin is effective to dislodge the pipe. Engagement of the knock-out pin with the pipe substantially tangentially, as illustrated, serves to dislodge the pipe with no substantial injury or deformation thereof. The provision of bores for receiving two knock-out pins, both located at off-center positions relative to the length of the pipe, serves to reduce the force required for dislodging the pipe.

In operation, after the pipe has been bent, if it is desired to test or check the bend for accuracy, the pressure in the ram cylinder 45 may be relieved enough to release the pressure of the pipe against the pipe engaging rollers 12. One or both of the rollers may be removed and the bending shoe 58 disconnected from the adapter 57 and removed from the bender. If the bend is satisfactory, the pipe may be dislodged from the bending shoe by use of the knockout pins 101 while the pipe and bending shoe are out of the bender. If it is not necessary to check the bend for accuracy, or if it is not necessary to remove the bending shoe from the pipe bender, as when the bending shoe projects outwardly beyond the upper frame plate 10 between the rollers 12 so as to expose the bores 97 and 98, the pipe may be dislodged from the bending shoe by means of the knockout pins 101 when the pressure of the pipe against the rollers 12 is relieved.

I claim:

1. In a pipe bender having a reciprocable force applying ram, in combination, an adapter connected to the ram, a bending shoe detachably connected to the adapter and having a pipe engaging face curved to produce a desired pipe bend and recessed transversely throughout its length, semi-circularly, to receive substantially half the outer circumference of the pipe to be bent, and means for removing bent pipe from the semi-circular recess in the bending shoe when the shoe and pipe wedged therein are detached from the adapter and removed from the bender, comprising, means defining a pair of bores in the bending shoe, each transverse to and intersecting the semi-circular recess in the pipe engaging face substantially tangentially at the bottom of the recess, and a pair of knockout pins, one receivable in each bore, and each having a tapered end portion engageable tangentially with pipe in the bending shoe, so that when delivered an impact blow, the pin is effective to dislodge the pipe.

2. For use in a pipe bender, a bending shoe having a pipe engaging face curved to produce a desired pipe bend and arcuately recessed transversely throughout its length, to receive a portion of the outer circumference of the pipe to be bent, means for removing a length of pipe from the recess in the pipe bending shoe after bending, comprising, means defining a bore in the bending shoe transverse to and intersecting the arc of the recess in the pipe engaging face substantially tangentially at the bottom of the recess, and a knockout pin receivable in the bore and having a tapered end portion engageable tangentially with pipe in the bending shoe, so that on striking the pin, the pin is effective to dislodge the pipe.

3. For use in a pipe bender having a reciprocable force applying ram, a pipe bending shoe structure, comprising, an adapter of relatively heavy, high strength material in the shape of a circular segment connectable along its chordtal side with the ram and having a continuous elongated force transmitting surface along its arcuate side, a plurality of different pipe bending shoes for bending pipes of different sizes and producing bends of different curvatures, each of relatively lightweight low strength material and of generally arcuate configuration having an outer arcuately curved pipe engaging face and an inner arcuately curved force receiving face detachably engageable with the force transmitting surface of the adapter to distribute ram forces evenly over a substantial length of the bending shoes.

4. For use in a pipe bender having a reciprocable force applying ram, a pipe bending shoe structure, comprising, an adapter of relatively heavy, high strength material connectible to the ram and having an elongated force transmitting surface, a plurality of different pipe bending shoes for bending pipes of different sizes and producing bends of different curvatures, each constructed of a relatively light weight, low strength material, each having a curved pipe engaging face recessed to receive a portion of the outer pipe surface, and each having an elongated force receiving surface detachably engageable with said force transmitting surface, said force transmitting and force receiving faces each having a length at least approximately half the length of the pipe engaging face to distribute the ram force evenly over a substantial length of the shoe, and means for detachably connecting said adapter to one of said shoes.

5. In a pipe bender having a pair of plates mounted in overlying spaced apart relationship to receive a length of pipe therebetween, a pair of pipe engaging rollers mounted between the plates in spaced appart relationship, and a ram mounted for reciprocal movement between the plates toward and away from a midpoint between the two rollers, in combination, a pipe bending shoe structure for producing a bend in a length of pipe positioned between the plates and against the pipe engaging rollers, comprising, an adapter of relatively heavy material connected to the ram and having a continuous elongated curved force transmitting face, a unitary bending shoe of relatively light weight material having a curved pipe engaging face to produce a desired bend, said shoe having a continuous elongated curved force receiving face opposed to the pipe engaging face and detachably engageable with said force transmitting face, said force transmitting and force receiving faces each having a length at least approximately half the length of said pipe engaging face to distribute ram forces evenly over the entire length of the interengaged force transmitting and receiving faces, and a pin removably positionable in aligned recesses in the adapter and the shoe for detachably connecting the shoe to the adapter.

6. In a pipe bender having a frame, a pair of pipe engaging rollers mounted on the frame in spaced apart relationship, and a ram mounted on the frame for reciprocable movement toward and away from a midpoint between the two rollers, in combination, a pipe bending shoe structure for producing a bend in a length of pipe positioned against the pipe engaging rollers, comprising, an adapter of relatively heavy, high strength material connected to the ram and having a continuous elongated curved force transmitting face disposed normal to the path of ram movement, a unitary bending shoe of rela tively lightweight, low strength material having a curved pipe engaging face to produce a desired bend and having a continuous elongated curved force receiving face disposed normal to the path of ram movement and detachably engageable with said force transmitting face, said force transmitting and force receiving faces each having a length at least approximately one half the length of said pipe engaging face to distribute ram forces evenly over a substantial length of the pipe bending shoe, cooperating surfaces on the adapter and on the bending shoe disposed parallel to the path of ram movement and detachably engageable to prevent twisting of the bending shoe relative to the adapter, and means for detachably connecting the bending shoe to the adapter.

7. For use in a pipe bender having a reciprocable force applying ram, a pipe bending shoe structure, comprising, an adapter generally in the shape of a circular segment having an abuttable surface of limited and localized area centrally disposed along its chordal side for engagement with the ram to transmit ram forces to the adapter, and having a continuous elongated force transmitting face along its arcuate side, at least approximately twice the length of said abuttable surface disposed normal to the plane of ram movement, and a unitary pipe bending shoe of generally arcuate configuration having an outer arcuately curved pipe engaging face and an inner arcuately curved force receiving face disposed normal to the plane of ram movement, complementary to said force transmitting face and detachably engageable therewith, said force transmitting and force receiving faces each having a length at least approximately half the length of said pipe engaging face for distributing ram forces evenly over a substantial length of the bending shoe.

8. A pipe bender, comprising, in combination, a pair of overlying spaced plates, a pair of spaced pipe engaging rollers between the plates, removable roller mounting pins one for each roller receivable in a bore in the roller and in apertures in the plates for removably retaining the rollers between the plates, a ram mounted for reciprocable movement between the plates toward and away from a line between rollers, an adapter connected to the ram, a pipe bending shoe having a pipe engaging face curved to produce a desired bend and arcuately recessed transversely, to receive a portion of the outer pipe surface, means detachably connecting the bending shoe to the adapter to permit removal of the shoe and a pipe wedged therein from between said plates when one of said roller mounting pins and the roller held thereby is removed from the mounted position between plates, and means for removing a length of pipe from the recess in the bending shoe while the shoe is removed from the bender including, means defining a bore in the bending shoe transverse to and intersecting the arc of the recess substantially tangentially at the bottom thereof, and a knockout pin receivable in the last recited bore and having a tapered end portion engageable on the pipe in the bending shoe to wedge against and dislodge the pipe when the pin is struck a hammer blow.

References ited in the file of this patent UNITED STATES PATENTS 1,275,377 Buckley et al. Aug. 13, 1918 1,355,713 Tench Oct. 12, 1920 1,635,987 Fiegel et al. July 19, 1927 1,863,693 Mingori June 2 1, 1932 1,865,025 Lindseen et al June 28, 1932 2,255,985 Pfauser Sept. 16, 1941 2,373,822 Ge-ppelt Apr. 17, 1945 2,382,266 Simonsen Aug. 14, 1945 2,477,910 Tal Aug. 2, 1949 2,801,559 Hawes Aug. 6, 1957 FOREIGN PATENTS 357,840 Great Britain Oct. 1, 1931 340,465 Great Britain Jan. 1, 1931 678,028 Great Britain Aug. 27, 1952 1,045,624 France July 1, 1953

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