METHOD AND APPARATUS FOR SHEARING BARS,BILLETS AND OTHER ELONGATED STOCK

Abstract: A method and apparatus for clamping a bar to be sheared, shearing the bar, and transmitting the shearing forces. An infeed clamping assembly (196, 198) and a moving shear blade assembly (430, 436, 438) are retained within a housing formed from a plurality of retainer plates (144, 146, 148) which are disposed between and connected to a pair of bolsters (112, 114) with keys (178, 186) inserted and interfitted into aligned key cavities (174, 176, 180, 182) in the retainer plates (144, 146, 148) and bolsters (112, 114). The infeed clamping assembly (196, 198) is provided with an infeed clamp (198) adapted to be pivoted on a support block (332) as the support block (332) and infeed clamp (198) are moved against a bar to accommodate variation in bar cross section along the length of the bar. A rectangular cage (430) having an interior guideway is provided to receive a portion of the bar to be sheared off. A backing clamp (436) is carried by, and slidably movable within the cage (430). The backing clamp (436) is wedged against one side of the bar portion to be sheared off until the other side of the bar is engaged by a part of the cage (430). The entire cage (430) and backing clamp (436) is forced by a ram (468) to shear the bar. This arrangement eliminates or substantially reduces the problem of bending of the bar during shearing.

Description: DESCRIPTION METHOD AND APPARATUS FOR SHEARING BARS, BILLETS, AND OTHER ELONGATED STOCK Technical Field This invention relates to bar stock shears of the type wherein one portion of an elongated metal bar is restrained against movement while an adjacent portion of the bar is displaced by a moving member to shear the bar. Background of the Invention Machines have been developed for hydraulically shearing bar stock and examples of such machines are described in the U.S. Patent No. 3,908,496 to Moelbert and the U.S. Patent No. 3,972,257 to Lazar, Jr. These machines are of the hydraulically operated type which include at least one main hydraulic ram for moving one portion of the bar relative to a clamped portion of the bar to effect a shearing of the bar. When a bar is sheared with a bar shearing machine, a first portion is clamped and restrained against movement while a moving member is forced against a second portion of the bar adjacent the first clamped portion to cause the bar to rupture and be sheared. With relatively large diameter bars (e.g., a six inch diameter round bar), the shearing force is considerable. With some prior art bar stock shears, the considerable shear force can cause a bending of the second portion of the bar relative to the fixed, clamped portion of the bar. The bending can cause the reaction forces on parts of the shear machine to be concentrated over relatively small areas. Such concentration of forces produces high stresses. It would be desirable to provide a bar stock shear OMP wherein the bending of the section to be sheared off could be eliminated or substantially reduced. Reduction in bending would increase tool life, improve the quality of the shear, permit shorter lengths of bar stock to be sheared, and would permit a decrease of the shear stroke length. Reduction of bending in the portion of the bar to be sheared off would also reduce the crushing effect at the shear plane. This can reduce the production scrappage rate. A reduction in the crush of the bar at the shear plane can also reduce the number of stress riser concentration points. This would be desirable because such stress riser concentration points can serve as propagations points for cracking or failure in the bar when the bar is subsequently treated (e.g., heated or forged) or used. The parts of the bar stock shear which are in contact with the bar adjacent each side of the shear plane, such as the dies and blades, are subjected to relatively large forces and over a period of time are worn down. Consequently, it would be desirable to reduce the bending of the portion of the bar being sheared off in order to reduce the wear rate of such parts and further, it would be desirable to provide a bar stock shear machine in which the parts more susceptible to wear can be easily and quickly replaced. With many bar stock shearing machines, hydraulic systems are employed to operate the shearing mechanisms. With hydraulic systems, forces or pressures . initially applied in one part of the system can be diminished or dissipated to some extent owing to the flexibility of hydraulic fluid lines, air that may be encapsulated in the hydraulic fluid / -"sJR ' in the system, the hydraulic capacitance in the system, etc. Consequently, it would be desirable to provide a bar stock shearing machine in which the disadvantages of a hydraulic system are eliminated or substantially reduced. In some bar stock shearing machines, the shearing mechanisms are retained within a housing. The reaction forces from the bar and from the shearing dies or blades are transferred to the housing. With relatively high shearing forces, stresses on the housing connections and bolts can be considerable. Therefore, it would be desirable to provide a housing which would eliminate or reduce such resulting stresses on the bolts employed in the structure and which would transfer the large reaction forces of the bar bending load to substantial structural members capable of withstanding such forces. Typically, bars to be sheared are not completely regular in cross section along their length. Consequently, difficulty can be encountered in firmly clamping a bar on the infeed side of the machine and in restraining the bar against movement while a portion is sheared off. Also, in bar stock shearing machines, the bars are typically fed in end-to-end fashion with the end of one bar abutting the end of the next upstream bar. If a first bar is of one size and the second bar is of another size, difficulty in clamping the bars where they abut can be encountered. Therefore, it would be desirable to provide an infeed clamping assembly in a bar stock shearing machine which would be able to accommodate a variation in cross section size along the length of a bar and which would be able to accommodate different size cross section bars in end-to-end alignment. Summary of the Invention In the preferred embodiment of the bar stock shearing machine described herein, a novel housing construction is provided for reducing or eliminating the shearing load-induced stresses on welded and bolted connections. Specifically, the machine has first and second end bolsters, a center bolster, and a main hydraulic cylinder positioned between the first end bolster and the center bolster. A retainer plate housing is positioned between the center bolster and second end bolster. Four tie rods securely join all three bolsters and maintain the hydraulic cylinder, bolsters, and retainer plate housing in a fixed position. The tie rods are stressed after assembly thus holding the entire assembly under a relatively . high co pressive load. A fixed or infeed die assembly and a movable die assembly adapted to receive a bar are disposed in the housing between the center bolster and the second end bolster. The movable die assembly is adapted to be moved relative to the fixed die assembly by the main hydraulic cylinder between the center and second end bolsters to shear the bar. The fixed and movable die assemblies are generally retained within the housing formed by a plurality of retainer plates extending between the center bolster and the second end bolster. The housing defines the die receiving cavity and restrains the die assemblies against movement that would result from the reaction forces generated during the shearing of the bar. Each retainer plate has two ends with one end being adjacent the center bolster and with the other end being adjacent the second end bolster. Each end of each retainer plate ' OMP defines therein at least one key cavity. The center bolster and second end bolster each define therein key cavities in alignment with and facing the key cavities of the retainer plates. A plurality of key members are provided with each key member being inserted and interfitted partially in a retainer plate key cavity and partially in an aligned bolster key cavity thereby providing an interlocking construction retained by the stressed tie rods. This eliminates bolts and welds that are necessary to join the confining members in conventional machines. The interfitted keys and key cavities thus form the only joints within the retainer plate and bolster assembly defining the die housing and serve to bear the component forces normal to the direction of movement of the movable die assembly which result from the shearing of the bar. The fixed or infeed die assembly is provided with a novel construction to accommodate the variation in cross section along the length of a bar. In particular, a guideway is provided through the bar stock shear machine for receiving bars in end-to-end alignment. The infeed die assembly includes a stationary die or clamp which defines a part of the guideway and is adapted to engage a first surface region of at least one bar. The infeed die assembly also includes a movable infeed clamp assembly on the other side of the guideway opposite the stationary die. The infeed clamp assembly is adapted to move between a retracted position providing clearance for the bar in the guideway • opposite the stationary die and an extended position to engage a second surface region of the bar generally opposite the first surface region. The movable infeed clamp assembly includes a support block and an infeed clamp. The support block has a partially cylindrical concave bearing surface and the infeed clamp has a partially cylindrical convex bearing surface received on the support block concave bearing surface. The infeed clamp is thus freely pivotable relative to the support block. The infeed clamp has an engaging face adapted to be oriented at an angle relative to the longitudinal axes of the bars when the infeed clamp is pivoted on the support block. A hydraulic cylinder actuated wedge i≤ provided to be moved relative to and against the support block to cause the infeed clamp assembly to move from the retracted position towards and against at least one of the bars. The infeed clamp engaging face can thus be forced against the second surface region of the bar to force the first surface region of the bar against the stationary die. As this occurs, the infeed clamp can pivot on the support block, in response to the reaction forces transmitted to the infeed clamp from the regions of contact with the bar, to orient the infeed clamp at an angle relative to the longitudinal axis of the bar and in contact with the bar in at least two longitudinally spaced-apart regions along the bar. Thus, according to one embodiment of the method described herein, a bar having a variation in cross section along its length can be more easily clamped. Specifically, as the infeed clamp is forced against the bar, the larger cross-sectional area portion of the bar will be contacted first by the infeed clamp. The clamp will swivel or pivot on the support block until another portion of the clamp engages a smaller cross-sectional area region of the bar. Thus, with this method, at least two points of contact can be obtained. Further, if the infeed clamp were being forced against one end of a first bar and one end of a second bar in abutting end-to-end relationship, the clamp would similarly pivot as necessary to provide at least a two point contact orientation. According to another aspect of the present disclosure, a novel method is provided for shearing a bar with a reduction in the bending of the portion of the bar to be sheared off. Specifically, a first portion of the bar is initially clamped and restrained against movement by the above-described infeed die assembly. Next, a movable force transmitting means or load bearing cage is provided for engaging at least first and second generally opposite surface regions of a second portion of the bar adjacent the clamped first portion. The bar is engaged on the first surface region of the second portion with the force-transmitting means and a first force is applied against the first surface region generally normal to the longitudinal axis of the bar while simultaneously the resulting reaction force is transmitted through the force-transmitting means to the bar on the second surface region of the second portion of the bar. The first force and the reaction force are thus exerted in opposing directions on the first and second surface regions, respectively, along the second portion of the bar generally perpendicular to the longitudinal axis of the bar to prevent bending of the second portion of the bar about the longitudinal axis of the bar relative to the first portion of the bar. A second force is then applied to the load bearing cage in a direction normal to the OMPI longitudinal axis of the bar sufficient to move the cage engaged with the second portion of the bar relative to the clamped first portion of the bar thereby shearing the bar without substantially bending the second portion of the bar relative to the first portion of the bar. In one embodiment of the apparatus employing the above-described method, the force-transmitting means or cage is a rectangular frame defining an interior guideway. A backing clamp is carried by, and slidably movable relative to, the cage frame. A hydraulic cylinder-actuated wedge is provided to slide against the backing clamp and move the clamp initially against the first surface region of the second portion of the bar. As the clamp is continued to be forced against the bar, the cage necessarily moves relative to the bar and to the clamp until the other end of the cage contacts the second surface region of the second portion of the bar. In this manner, the second portion of the bar is securely clamped and restrained against bending. A main ram is provided for moving the entire cage relative to the clamped first portion of the bar to cause the second portion of the bar to be sheared from the first portion of the bar. With the novel shearing mechanism operating in accordance with the method as described above, the quality of the shear is improved because the bending of the sheared-off portion of the bar is substantially reduced or eliminated during the shearing process. Further, the mechanical wedge engaging system that is employed to grip the portion of the bar to be sheared off and to prevent bending thereof provides a more positive restraint against- bending than in those types of bar shear machines O wherein a main shearing member or clamp is moved against the bar and wherein an independently supported clamp or member is provided behind the bar to reduce the bending. With such conventional bar shear machines, where hydraulic cylinders are employed to operate the clamp behind the bar to reduce bending, the reduction in pressurization arising from expansion and flexing of cylinders and hoses and .from encapsulated air can permit movement of the backing clamp and thus, permit a greater bending. In contrast, with the novel load bearing cage assembly and wedge-operated backing clamp described herein, loosening of the backing clamp is substantially avoided. The novel combination of elements in accordance with the present invention is thus seen to yield desirable and beneficial results—results which provide a substantial improvement over the prior art. Numerous other advantages and features of the present invention will become readily apparent from the following detailed description of the invention and of one embodiment thereof, from the claims and from the accompanying drawings. Brief Description of the Drawings In the accompanying drawings forming part of the specification and in which like numerals are employed to designate like parts throughout the same, Figure 1A and IB are diagrams illustrating a prior art method of shearing a bar in a bar stock shearing machine; Figure 1C is a diagram of a novel method of shearing a bar; Figure 2 is a fragmentary side view of the novel bar stock shear machine described herein; ■ ^URE Figure 3 is a fragmentary plan view of the top of the machine illustrated in Figure 2; Figure 4 is an enlarged end view taken generally along the plane 4-4 in Figure 2; Figure 5 is a fragmentary, cross-sectional view taken generally along the plane 5-5 in Figure 4; Figure 6 is a fragmentary, cross-sectional view taken generally along the plane 6-6 in Figure 4; Figure 7 is a perspective, exploded view of the retainer plate and die housing assembly with external and internal components, such as tie rods, wear plates and shear clamps, omitted for purposes of clarity; Figure 8 is an enlarged, cross-sectional view taken generally along the plane 8-8 in Figure 2; Figure 9 is an enlarged, fragmentary cross-sectional view taken generally along the plane 9-9 in Figure 2; Figures 10A, 10B, and IOC are diagrams illustrating the novel method for clamping a bar or bars on the infeed side of a bar shearing machine; Figure 11 is a greatly enlarged, fragmentary, partial cross-sectional -view taken generally along the plane 11-11 in Figure 2; Figure 12 is a view similar to Figure 11 but showing the range of pivotal movement of the infeed clamping block in dashed lines; Figure 13 is an enlarged, fragmentary, partial cross-sectional view similar to Figure 11; Figure 14 is a fragmentary cross-sectional view taken generally along the plane 14-14 in Figure 13 showing the stationary infeed backing die insert and holder; Figure 15 is a fragmentary cross-sectional view taken generally along the plane 15-15 in Figure BU RE -ll- lS showing the movable shear die assembly insert and cage; Figure 16 is an enlarged cross-sectional view taken generally along the plane 16-16 in Figure 15; Figure 17 is an enlarged fragmentary, cross-sectional view taken generally along the plane 17-17 in Figure 15; Figure 18 is a fragmentary cross-sectional view taken generally along the plane 18-18 in Figure 13; Figure 19, located on the sheet with Figures 16 and 17, is an enlarged cross-sectional view taken generally along the plane 19-19 in Figure 18; Figure 20 is a greatly enlarged, fragmentary side view similar to Figure 2, showing the infeed clamp assembly actuator mechanism located on the central portion of the machine; Figure 21 is a fragmentary cross-sectional view taken generally along the plane 21-21 in Figure 20; Figure 22 is an enlarged, fragmentary cross-sectional view taken generally along the plane 22-22 in Figure 20; Figure 23 is a fragmentary cross-sectional view taken generally along the plane 23-23 in Figure 20; Figure 24 is a fragmentary, cross-sectional view taken generally along the plane 24-24 in Figure 23; and Figure 25, located on the sheet with Figure 21, is a fragmentary, cross-sectional view taken generally along the plane 25-25 in Figure 23. Description of the Preferred Embodiment This invention may be used in many different forms. This specification and the accompanying drawings disclose only one specific form of novel methods and apparatus. The invention is not intended to be limited to the embodiments of the features illustrated and described, and the scope of the invention will be pointed out in the appended claims. The precise shapes and sizes of the components herein described are not essential to the invention unless otherwise indicated. For ease of description, the bar shear apparatus will be described in normal operating position, and terms such as upper, lower, horizontal, etc., will be used with reference to this normal operating position. It will be understood, however, that the apparatus may be manufactured, stored, transported and sold in an orientation other than the normal operating position described. The bar shear apparatus has certain conventional mechanisms, the details of which, though not fully illustrated or described, will be apparent to those having skill in the art and an understanding of the necessary functions of such mechanisms. Referring now to the drawings. Figures 1A and IB diagrammatically illustrate a method of shearing bar stock as taught by the prior art. A bar 50 is fed into the infeed side of a bar stock shearing machine and clamped or fixed against movement by means of clamps 52 and 54. The clamps 52 and 54 are engaged with a first portion 56 of the bar from which a second portion 58 extends and which second portion 58 is to be sheared off. A shear blade or die 60 is moved to engage one side of the second portion 58 of the bar 50. The shear blade 60 may be moved against the bar by means of a conventional hydraulic cylinder-piston actuator 62. MPI At the same time, a backing member or die clamp 64 is moved against the side of the bar opposite the shear blade 60. Die 64 may be moved against the bar by means of a conventional hydraulic cylinder-piston actuator 66. It is to be noted that backing die 64 is operated independently of shearing die or blade 60. The force exerted by actuator 62 thus has to be great enough to overcome both the strength of the bar and the backing force of actuator 66 in order to rupture and shear the bar at the shear plane P between the two clamped bar portions 56 and 58. As illustrated in Figure IB, when actuator 62 forces shear blade 60 against the second portion 58 of the bar, the force of the blade 60, being transmitted through the bar, must necessarily overcome the backing force of die 64. The movement of die 60 is indicated by arrow 70 in Figure IB and the resulting movement of backing die 64 is indicated by arrow 72 in Figure IB. The end of the shear blade 60 closest to the shear plane P is subjected to a reaction load indicated by arrow 74 as the bar 50 initially starts to bend about a transverse axis indicated by the torsion arrow 76. Similarly, backing die 64 is subjected to a reaction load at its outer end as indicated by arrow 78. On the restrained portion 56 of the bar 50, the clamps 52 and 54, being restrained against all movement during the shearing operation, do not permit bending of the first portion of the bar 56. However, to the extent that there may be some "looseness" in the clamps 52 and 54, the reaction load on clamp 54 would be greatest at the outer end of clamp 54 as indicated by the load acting at arrow 80 and the reaction load on clamp 52 would be greatest on the end of the clamp 52 adjacent the shearing plane P as indicated by the arrow 82. The concentration of loads at points 74 and 78 on the clamps 60 and 64, respectively, can cause rapid die wear. Further, owing to the bending of the bar 50, transverse loads are transferred to the shear clamp 60 as indicated by arrow 84 and to the backing die clamp 64 as indicated at arrow 86 in Figure IB. These side loads must be taken by the machine housing or retainer plate structure. Consequently, the housing or retainer plate structure must be designed for these loads which, when relatively large bar stock is sheared, can be considerable. Such loads may be more than half of the force required to shear a bar. Owing to the initial bending of the bar 50, the shearing of the bar 50 requires a longer stroke of the actuator 62, and hence a longer operational time. Further, the bending of the bar decreases the quality of the shear. The bending occurs until the ultimate shear strength of the bar is exceeded and until there is an actual displacement along the shear plane P. The above described bending of a bar stock and the disadvantages associated with that bending can be substantially reduced, if not eliminated, with a novel method as illustrated in Figure 1C. The bar 50 is restrained against movement on its first portion 56 by clamps 52 and 54. Adjacent these clamps 52 and 54, the second portion 58 of the bar is received in a movable force transmitting means, such as a cage or holder 90. The cage 90 may be moved from a loading position (for receiving the bar 50) in a direction to shear the bar by a suitable actuator 62. As can be seen in Figure 1C, the cage 90 is adapted for engaging at least first and second generally opposite surface regions of the second portion 58 of the bar. To this end, the cage 90 carries a clamp 92 and a means 94 for moving the clamp 92 against a first surface region of the second portion 58 of the bar. The clamp moving means 94 may include a wedge 96 reciprocated by a hydraulic cylinder actuator 98 against an inclined surface 100 of the clamp 92. A novel method is provided wherein the bar 50 is initially positioned with the first portion 56 clamped and restrained against movement and with its second portion received in the cage 90 which is initially aligned in a position for receiving the bar with clearance around the bar. Next, the clamp 92 is forced by wedge 96 against the first surface region of the second portion 58 of the bar. Continued force on clamp 92 causes the cage 90 to move relative to both the bar 50 and to the clamp 92 engaged with the bar 50 until the cage 90 becomes engaged with a second surface region of the second portion 58 of the bar opposite the clamp 92. In this manner, the second portion 58 of the bar is tightly and mechanically clamped so as to prevent or substantially reduce bending. Next, the actuator 62 is operated to move the entire cage assembly 90 as indicated by arrow 102 to move the bar second portion 58 perpendicular to the longitudinal axis of the bar to thereby shear the bar along the shear plane P. Since the second portion 58 of the bar is securely clamped, and since bending is thereby eliminated or substantially reduced, reaction forces are more uniformly distributed along the second portion 58 within the cage 90. Thus, concentrated loads, such as those illustrated in Figure IB by arrows 74 and 78 for the "gOREX^ OMPI prior art, are much reduced. Thus, the wear of the shearing mechanism is substantially reduced. Similarly, since the force on the second portion 58 of the bar is more uniformly spread over the surfaces engaged by the cage 90 and clamp 92 compared with the concentrated loads indicated at arrows 74 and 78 in Figure IB, the tendency of the bar to be crushed at the shear plane and to generate stress riser concentration points is substantially reduced. Thus, the probability of cracking during later manufacturing operations on the bar or during use of the bar, is substantially reduced. A preferred embodiment of a bar stock shearing machine for effecting the method described above is designated generally by numeral 103 in Figures 2 and 3. The bar stock shear includes a pair of end bolsters, first end bolster 110 and second end bolster 112, and a center bolster 114 forming major structural elements of the unit. Interposed between the first end bolster 110 and the center bolster 114 is a hydraulic cylinder 116. Similarly, interposed between center bolster 114 and second end bolster 112 is a die housing assembly generally indicated at 118. Each bolster is apertured at its four corners and tie rods 121-124 are inserted through the respective apertures. The entire assembly is joined together by means such as nuts 126-133. The tie rods are preferably pre-stressed by heating them and tightening the nuts while the rods are hot. This procedure places the apparatus under a relatively high compressive load. The assembly may be supported on a continuous bed plate 136 and maintained at a convenient height by support legs 138. An opening or guideway 140 is defined on the infeed side of the machine 108 as illustrated in ' ■ ξ,Xi - Figure 2. Bar stock is inserted through the guideway as best illustrated in Figure 3 where a bar 50 is shown with a first portion 56 entering the infeed side of the machine and with a second portion 58 extending from the outfeed side of the machine. Typically, the bars are automatically fed by suitable conventional mechanisms (not illustrated) in end-to-end relationship into the bar shear machine. Further, such mechanisms typically automatically feed a predetermined length of bar into the machine for shearing off predetermined lengths or slugs of the bar. The particular feeding mechanism forms no part of the present invention and will not be described in detail. Similarly, mechanisms may be provided at the outfeed side of the bar shear for stacking, weighing, or conveying the sheared bar stock slugs to subsequent stations. Such outfeed mechanisms form no part of the present invention and will not be described. In operation, the bar 50 is clamped or restrained against movement on the infeed side of the machine by mechanisms to be described in detail hereinafter. Next, the clamped bar is sheared by operation of the cylinder actuator 116 and a moving shear blade assembly in a manner to be described in more detail hereinafter. During the shearing process, the loads or reaction forces must be accommodated by the machine. To this end, a novel die housing or retainer structure is incorporated in the machine as will next be described. The die housing assembly 118 between bolsters 114 and 112 is configured so that the resulting loads and forces are transmitted directly to the bolsters without reliance upon bolted or welded joints. With reference to Figure 7, the novel interlocking system of the die housing 118 can be seen in an exploded view. The internal parts, such as the tie rods, shearing and retaining clamps, pistons, and wear plates, have all been omitted for purposes of clarity. Disposed between the center bolster 114 and the second end bolster 112 are a plurality of retainer plates, namely a generally U-shaped retainer plate 144, an upper infeed side retainer plate 146 and an upper outfeed side retainer plate 148. The bottom U-shaped retainer plate 144 is provided with bores 150 and 152 adapted to align with bores 154 and 156, respectively, in the second end bolster 112 and adapted to align also with bores 158 and 160, respectively, in the center bolster 114. 3ottom retainer plate bore 150 and the aligned bolster bores 158 and 154 accommodate tie rod 123 (Figures 2 and 4) . Bottom retainer plate bore 152 and the aligned bolster bores 160 and 156 receive the tie rod 124 (Figures 2 and 4) . The plate 144, as well as the other plates, may, if desired, comprise a plurality of suitably interlocked members. Upper infeed side retainer plate 146 defines a bore 162 adapted to align with a bore 164 in second end bolster 112 and a bore 166 in center bolster 114 for receiving tie rod 122 (see Figures 2 and 4) . Similarly, upper outfeed side retainer plate 148 defines a bore 168 adapted to be aligned with a bore 170 in second end bolster 112 and a bore 172 in center bolster 114 for receiving tie rod 121 (see Figures 2 and 4) . To provide for lateral transfer of loads between the retainer plates and the center and second end bolsters, a novel key system is provided. Specifically, bottom retainer plate 144 defines three key cavities 174 on each end. That is, three key cavities 174 face the second end bolster 112 and three key cavities (not visible in Figure 7) face center bolster 114. The center bolster 114 has similar key cavities 176 aligned with the facing key cavities of the bottom retainer plate 144. Similarly, second end bolster 112 is provided with key cavities (not visible in Figure 7) which are aligned with the facing key cavities 174 in the bottom retainer plate. Key members 178 are provided to interfit in the key cavities with substantially one half of the thickness of each key member 178 extending into the bottom retainer plate 144 and one half of each key member extending into the respective center or end bolster. In this manner, the transverse loads which result from the shearing operation and are imposed by the shearing blades onto the bottom retainer plate can be transferred to the center and second end bolsters. In a manner similar to that described for the bottom retainer plate 144, the upper infeed side retainer plate 146 is provided with a key cavity 180 at each end and the upper outfeed side retainer plate 148 is provided with a key cavity 182 at each end. The center bolster 114 is provided with a pair of key cavities 184 aligned with and facing the key cavities in the upper retainer plates. Similarly, the second end bolster 112 is provided with key cavities (not visible in Figure 7) which are aligned with and face the key cavities 180 and 182 in the upper retainer plates. Key members 186 are provided for joining the upper retainer plates 146 and 148 to the center bolster 114 and second end bolster 112 in the same manner in which the bottom retainer plate 144 is joined to the center bolster 114 and second end bolster 112. With the key members properly interfitted in the retainer plates and bolsters, the assembly provides a secure housing for the internal clamps and dies with the interfitted key members and key cavities serving to bear the component forces normal to the direction of movement of the movable shear dies and blades operating within the housing as will be explained in detail hereinafter. The assembled die housing is seen to have an opening accessible from the top of the machine between the upper retainer plates 146 and 148. This opening permits removal and installation of internal parts, including replaceable shear blades and die inserts to be described in detail hereinafter. A novel method is provided for clamping the bar from which a slug is to be sheared and for restraining it against movement as it is sheared. An infeed clamping assembly for effecting this method.is mounted partially within the above-described retaining plate housing on the infeed side of the machine 108. Specifically, as illustrated in Figure 2, the novel clamping assembly includes a backing or bar support clamp or die 196 and a movable infeed clamp 198, both being disposed within the opening defined between the bottom retaining plate 144 and the upper infeed side retaining plate 146 and defining therebetween them the aperture or guideway 140 into which the bars are fed. The backing bar support die or clamp 196 is best illustrated in Figure 6 which shows the bar support clamp 196 slidibly supported on a support surface 200' of the bottom retainer plate 144. The clamp 196 has a V-shaped notch defining a TU bar-engaging surface 197 and the clamp 196 can be moved on the support surface 200 towards or away from a bar within the guideway. Typically, the position of clamp 196 is initially set and the clamp 196 is prevented from being moved by a bar by properly adjusting a ram 202 carried within channel 204 of the bottom retainer plate 144 (Figure 7) . The ram 202 is threadingly engaged with a rod 206 which projects through a bore 208 in the second end bolster 112 and which may be rotated from the back of the machine as necessary to move the ram 202 to the desired position. The movable infeed clamp 198, which is omitted for clarity from Figure 6, is disposed between the upper infeed side retainer plate 146 and the bottom retainer plate 144 as best illustrated in Figure 23. To this end, the bottom retainer plate 144 defines a channel 310 and the upper infeed side retainer plate 146 defines a channel 312 for receiving, respectively, guide keys 314 and 316 respectively. Key 314 projects within a channel 318 in the bottom of the clamp 198 and key 316 projects within a channel 320 in the top of clamp 198. A pair " of plates, 322 and 324 are secured to the top of the infeed side of bottom bracket 144 to provide suitable sliding bearing surfaces. Clamp 198 can thus be moved towards or away from the backing clamp 196 on the plates 322 and 324 to engage a bar disposed therebetween in the guideway. The mechanisms by which clamp 198 is thus moved will be described in detail hereinafter. In order to accomodate cross section variation along the length of a bar, clamp 198 is supported so that it can pivot with respect to a vertical plane passing through the machine. Specifically, with reference to Figures 11, 12 and 13, the clamp 198 has a generally V-shaped clamping or engaging face 326 on one side and a partially cylindrical convex bearing surface 328 on the other side which is received in a partially cylindrical concave bearing surface 330 defined within a support block 332. A spring 334 is disposed within aligned bores 336, 338, and 340 of center bolster 114, support block 332, and clamp 198, respectively, for holding the clamp 198 and support block 332 together and for biasing the assembly towards the center bolster 114. To this end, spring 334 is secured to rod 342 at one end on center bolster 114 and to pin 344 at the other end in clamp 198. Rod 342 is threadingly engaged with a collar 346 mounted to center bolster 114 so that the tension on the spring 334 may be varied by appropriate rotation of the collar 346 relative to rod 342. With reference to Figure 23, it can be seen that the channel 320 in the top of clamp 198 is wider than the interfitted key 316 and that the channel 318 in the bottom of clamp 198 is wider than the interfitted key 314. Thus, the clamp 198 can be rotated, relative to a vertical plane passing through the longitudinal axis of a bar to be clamped, as indicated in dashed lines in Figure 12. This rotation is accomodated by the partially cylindrical mating bearing surfaces 328 and 330 of the clamp 198 and support block 332, respectively. The infeed clamp 198 extends towards the middle of the machine as illustrated in Figures 11, 13, 14, and 23. As best shown in Figures 14 and 23, the top and bottom of the clamp 198 is notched inside the machine at its upper and lower corners at 350 and 352, respectively. The notches are slanted at 354 ... O and 356 so that the clamp 198 fits within an aperture 360 of a stationary backing die holder assembly 366. Opposite the notched end of the movable clamp 198 is a second backing die or support clamp 370 which is supported within the die holder assembly 366 as best illustrated in Figure 14. The die 370 has a partially circular configuration with a generally V-shaped cut out for providing an engaging face 372 opposite the engaging face 326 of movable infeed die 198. The die 370 is retained within the holder 366 by locking pins 377 and 378 which pass through notches or channels in the top and bottom, respectively, of the die 370. The pins 377 and 378 are retained within holder 366 by plugs 377a and 378a, respectively. As best shown in Figures 2, 8, and 14, the entire holder 366 is secured within the machine with bolts 373-376 connecting the holder to the retainer plates 144 and 146. The bolts are not subjected to any significant transverse shear stress since the portion of the force on the bar during shearing that is transmitted back to the holder 366 is transferred . to the second end bolster 112. The holder 366 can be easily removed from the machine by removing the bolts and then pulling it upwardly through the space between the upper infeed side retainer plate 146 and the upper outfeed side retainer plate 143. When the holder 366 is thus removed, the pins 377 and 378 may be removed to allow replacement of the backing clamp 370. The advantage of the novel infeed' clamp structure is best illustrated with references to Figures 10A, 10B and IOC. In these figures, the backing clamp or die 196, the movable infeed clamp 198, the support block 330 and the bar 50 are - URE ^ illustrated only schematically for purposes of clarity. Figure 10A shows a bar 50' with a generally uniform cross section along its length. The clamp 198 can float or pivot on the support block 330 to align its engaging face 326 in generally continuous contact with the bar 50'. Figure 10B illustrates two bars of different sizes being clamped. Specifically, bar 50' has a larger cross section than bar 50''. The bars are fed into the clamping assembly in end-to-end relationship. As can be seen, when the clamp assembly is moved against the bars, the clamp 198 pivots on the support block 332 in response to the reaction forces transmitted to the clamp 198 from the regions of contact with the two bars. This orients the infeed clamp 198 at an angle relative to the longitudinal axis of the bars and in contact with the bars in at least two longitudinally spaced-apart regions. In this manner, two points or lines of contact are created with a point of contact being made on each of the two bars. Thus, with this novel ' method of clamping two bars of different cross sectional area, it is possible to shear each bar to relatively short lengths while still providing adequate infeed clamping capability. Figure 10C illustrates the novel clamping assembly in operation with a bar 50' ' ' which has a bump or bulge B. When the clamp 198 is brought against the bar 50* ' ' in the region of the bulge, the clamp pivots on the block 332 to establish at least 2 point contact with the bar 50 , , ! . One region of contact is at the high point of the bulge B and the other region of contact is on the surface of the bar at a location spaced from the bulge B. This provides a better clamping action than prior art non-pivoting clamping assemblies. The infeed clamping assembly is moved toward and forced against a bar to effect clamping thereof by a novel wedge drive system best illustrated in Figures 11 and 20-25. Specifically, the support block 332 is provided with two slanted surfaces 380 and 382 which are engaged by vertically reciprocable wedges 384 and 386, respectively. As best illustrated in Figure 21, wedges 384 and 386 are secured to rods 388 and 390' respectively. The rods 388 and 390 are received in a mounting assembly 392 which is connected through piston rod 394 to a hydraulic cylinder actuator 396 supported from a frame structure 393. As best illustrated at Figure 22, assembly 392 is guided for its reciprocating movement by guide members 397 and 398 engaging either side of assembly 392. The entire assembly 392 may thus be reciprocated by the actuator 396 to move the wedges 386 and 384 up and down relative to the support block 332. As best illustrated in Figure 2, the wedges - 384 and 386 are restrained against lateral movement by exterior cover plate 387 and by internal guides 389. As best illustrated in Figure 24, when the cylinder 396 is actuated to move the wedges 384 and 386 downwardly, the support block 332 is moved outwardly to force the floating clamp 198- against a bar to be sheared. When the wedges are retracted by the cylinder 396, the spring 334 (Figure 11) pulls the clamp 198 and support block 332 back and maintains the support block 332 in contact with the wedges. In order to provide a maximum clearance for initial bar loading in the guideway between the - URE clamp 198 and backing die 196, a novel adjustment mechanism is provided. Specifically, as best illustrated in Figures 21-23 the rods 388 and 390 connected to ' the wedges are threaded along their lengths and are engaged with gears 400 and 402, respectively. As illustrated in Figure 22, the vertically reciprocable assembly 392 also carries a cross shaft 404 having a worm gear 406 engaged with gear 400 and a worm gear 408 engaged with gear 402. Hand wheels 410 and 412 are mounted on opposite ends of the shaft 404 by which the shaft may be rotated to turn the gears 400 and 402. Since the gears 400 and 402 are threadingly engaged with the rods 388 and 390, respectively, the vertical position of the wedges 384 and 386 may be varied by operation of either of the hand wheels 410 or 412. In operation, the initial elevation position of the wedges 384 and 386 is set by one of the hand wheels 410 or 412 to provide a maximum clearance for the size of the bar to be sheared. Once this wedge position is set, operation of the machine includes the automatic actuation of cylinder actuator 396 to move the wedges downwardly to force the clamp 198 tightly against the bar. When a new bar is to enter the machine, it is especially important to have a sufficiently large clearance. However, once the bar has entered the machine, it is not usually necessary to have a large clearance in the infeed clamp assembly during successive increments of bar feeding. Consequently, with the apparatus herein described, it is possible to terminate the retraction operation of the wedges by actuator 396 short of the full return stroke. This can be accomplished by interlocking a limit switch 416 (Figure 24) with the control system for OM terminating the actuation of cylinder 396 before it has retracted the wedges to the full stroke height. The limit switch 416 is preferably actuated by a finger element 418 carried by the assembly 392 as best illustrated in Figure 24. When a new bar is to enter the machine in an end-to-end alignment with a bar already in the machine, a suitable sensing mechanism on the infeed conveyor can be provided to override the limit switch 416 so that the cylinder actuator 396 is permitted to operate through its full retraction stroke and thereby provide the maximum set clearance for admission of the new bar. After the bar has been securely clamped by the infeed assembly in the manner described above, the actual sharing operation can take place. A novel shearing method and apparatus for effecting such an operation is provided. As best illustrated in 13-18, a movable force-transmitting means or load bearing holder or .cage 430 is disposed adjacent the stationary backing die holder assembly 366 and within the housing defined by the retainer plates. The cage 430 is a substantially right rectangular prism-shaped frame defining a central opening in which are disposed a bar backing clamp or die 436 and a shear blade 438. The backing die 436 is adapted for sliding movement relative to the cage 430 toward and away from a bar to be sheared while shear blade 438 is retained so that it is prevented from moving relative to the cage 430. Shear blade 438 has a substantially circular cross section with a V-shaped notch cut out defining a bar engaging face 440 and is retained within the cage 430 by bolts 442 and 444 which pass through notches in the top and bottom, respectively, of the shear blade 438. As best illustrated in Figures 15, 16 and 18, the backing clamp or die 436 defines a V-shaped notch or bar engaging surface 446 on one side and a channel with a slanted bearing surface 448 on the other side. The slanted bearing surface 448 is adapted to be engaged by a wedge 450 as best illustrated in Figures 17 and 18. The wedge 450 is secured to a rod 454 connected to a cylinder actuator 456 mounted to the top- of the cage 430. The rod 454 and the upper portion of the wedge 450 are received between a pair of guide members 458 and 460 which project downwardly from the cylinder actuator 456 into a cavity 462 within the cage 430. In operation, actuation of the cylinder 456 to move the wedge 450 downwardly forces the backing clamp 436 against the bar 50. An appropriate cavity 464 is provided in the cage 430 below the wedge 450 . to receive the projecting bottom portion of the wedge 450 as it is moved downwardly by the cylinder 456. Initially, the backing clamp 436 is positioned sufficiently away from the shear blade 438 (to the right as viewed in Figure 18) to provide adequate clearance for an incoming bar. When the wedge 450 is forced against the backing clamp 436 by actuator 456, the backing clamp 436 moves against the bar (to the left as viewed in Figure 18) and engages the bar. Note that backing clamp 436 is slidibly disposed within the cage 430 and the cage 430 is slidibly disposed within the die housing (on wear plate 466 on the bottom retainer plate 144 as illustrated in Figure 8). Thus, further downward movement of wedge 450 will cause cage 430 to move and carry the shear blade 438 against the bar (to the right as viewed in Figure 13). In this manner, the portion of the bar to be sheared is securely clamped between the backing clamp 436 and the shear blade 438. The positioning of the holder 366 and the movement of the cage 430 therealong are accommodated by various side and end shim and wear plates positioned within the retainer plate cavity. The bar is then sheared by actuation of the hydraulic cylinder 116 (Figures 2 and 3) . The cylinder 116 acts on a main ram 468 extending through a bore 469 in center bolster 114 (Figure 18) to move the entire cage 430 (to the right as viewed in Figure 18) to shear the bar. After the bar has been sheared, the cage 430 is returned to the initial loading position and the backing clamp 436 is moved to a clearance position relative to the shear blade 438 by mechanisms as will next be described. First, the entire cage 430 is returned to the initial position by a small return ram 474 operated by a hydraulic cylinder actuator 476. The distal end of ram 478 is received in a suitable cavity 478 defined in the end of cage 430. As viewed in Figure 18, operation of the actuator 476 to move the ram 474 to the left will return the cage 430 to the initial bar loading position. To "open up" the backing clamp or die 436 to provide clearance for the next incoming portion of the bar, a novel return mechanism is provided. Specifically, and as best illustrated in Figures 15-17, a pair of side links 484 and 486 are pivotally mounted about pin 488 at their upper ends on either side of cage 430. To this end, cage 430 is provided with a channel 490 for receiving link 484 and with a channel 492 for receiving link 486. The links 484 and 486 are thus recessed in the channels in the cage 430 and may pivot within the channels about the pin 488. A pin 494 is mounted through backing clamp 436 and is received on each end within elongated apertures 496 and 498 in the links 484 and 488, respectively. A pin 500 joins the bottom ends of the links 484 and 486. The bottom portion of cage 430 defines a cavity 502 to allow movement of the pin 500 and to receive a pin engaging block 504. The cavity 502 communicates at the sides of cage 430 with the link channels 490 and 492. Block 504 defines a channel 506, the vertical walls of which are adapted to engage the pin 500. Block 504 is slidibly disposed within cavity 502 on plate 466 and is connected to rods 508 and 509 passing through bore 510 in a second end bolster 112. Rod 509 is connected to a hydraulic cylinder actuator 512 mounted to bolster 112. After the cage 430 has been returned by actuator 476 to the initial bar loading position, the actuator 512 is operated to move the block 504 to the right, as viewed in Figures 15 and 18 to move pin 500 to the right. This causes the links 484 and 486 to pivot about pin 488 in a counterclockwise direction. This movement of the links forces pin 494, and hence the backing clamp 436, to the right, as viewed in phantom lines in Figure 15, to provide an initial clearance for the incoming bar. Operation of the actuator 476 to return the cage 430 back to the initial bar loading position may be effected through the use of a suitable control system with limit switch actuation. Specifically, as best illustrated in Figures 3, 4, and 6, the second end bolster 112 is provided with a bore 514 for receiving a travel indicating rod 516 extending ■ ^XJ E OM? therethrough. Inside the retainer housing, the rod 516 is connected to ram 474 by a bracket 517 engaging a circumferential channel 519 in the ram 474. The rod 516 has oppositely facing flat surfaces 518 and 520 extending beyond bolster 112. Mounted to the end of the rod 516 projecting on the exterior side of the second end bolster 112 are adjustable clamps 522 and 524. The clamps may be adjusted to any position on the flattened portion of the rod 516 extending exterior of the second end bolster 112. As best illustrated in Figures 4 and 6, two limit switches, 526 and 528, may be provided to be actuated by downwardly extending portions of the clamps. In Figure 4, limit switches 526 and 528 are shown supported from a bracket 530 secured to the exterior surface of the second end bolster 112. Thus, movement of the ram 474 causes the clamps 522 and 524, carried on rod 516, to actuate their associated limit switches. The interaction of the limit switches with the control system in the operation of shearing the bar will next be explained. When the machine is ready to receive a bar, the infeed side clamp assembly, comprising clamps 196 and 198, is open to provide appropriate clearance. Also, the shearing clamps, clamps 436 and 438, are also open to provide the initial loading clearance. When the bar has been fed into the machine a predetermined amount by the bar feeding mechanism (not illustrated) , an appropriate signal from the bar feeding mechanism initiates the clamping of the bar on the infeed side by actuating the cylinder 396 to move the infeed clamp 198 against the bar and force the bar against the backing clamp 196. At the same time, and from the same infeed mechanism signal, the cylinder 456 is actuated to move the backing clamp "gTJREX OMPI yλr , WIPO 436 against the bar. When the backing clamp 436 engages the bar, continued force applied to the clamp 436 by the cylinder 456 causes the cage 430 to move relative to both the bar and clamp 436 to engage the shear blade 438 securely against the bar. It is to be noted that the cylinder 476 may be continuously pressurized so as to provide a suitable nominal return force (e.g., 20 tons) against the cage 430. This force will be overcome by the movement of the cage 430 under the actuation of the wedge cylinder 456 and main ram cylinder 116. The force exerted by these cylinders is relatively great and of course easily overcomes the continuously applied return force of cylinder 476. A pressure switch (not illustrated) in the hydraulic circuit of the wedge actuator 456 can be provided to actuate the main ram cylinder 116 to move the main ram 468 against the cage 430. As the cage 430 is moved by the main ram 468 (to the right as viewed in Figure 18) , the bar is sheared and the cage 430 moves to the end of its allowable travel within the housing. This maximum travel may be sensed by the limit switch 528 associated with the travel clamp 522 (Figures 3 and 6) . Alternatively, the reduction in pressure in the hydraulic system supplying the main cylinder operator 116 could also be sensed. In any case, a signal generated at the completion of the shear step is used to reverse the operation of the main ram cylinder 116 and to reverse the operation of the wedging cylinder 456. Since the cylinder 476 is continuously pressurized, reversal of the main ram cylinder 116 permits the low pressure cylinder 476 to force the cage 430 back to the initial bar loading position. As this is occurring, the wedge 450 is being retracted by cylinder 456. y- wip The second limit switch 526 associated with travel clamp 522 (Figures 3 and 6) senses the return of the cage 430 to the initial bar loading position and actuates the cylinder 512 to move the backing clamp 436 away from the shear blade 438 to thus "open up" the assembly and provide clearance for the next portion of the bar to be inserted therein. With the novel apparatus for shearing bar stock described above, it can be seen that the moving shear assembly, including the cage 430, shear blade 438, and backing clamp 436, can be easily lifted from the die area of the machine to enable rapid replacement of parts that are susceptible to wear, such as the clamp 438 and clamp 436. Further, the entire machine may be operated in either vertical or horizontal orientations. With the novel apparatus described herein, the clamping of the portion of the bar to be sheared between the backing clamp 436 and shear blade 438 is effected by means of a positive metal-to-metal transference of load through the drive wedge 450. Any tendency of this portion of the bar to bend is countered by the direct mechanical restraint which does not oppose (and hence does not substract from) the shearing force applied by the main shearing ram cylinder 116. Bending of the bar is substantially reduced with this apparatus so that the deformation of the bar occurs primarily across the shear plane. In the preferred embodiment of the bar shear apparatus illustrated, it is to be noted that the center bolster 114 is interlocked with the housing retainer plates 144, 146, and 148 and receives the main ram 468 so that the piston rod bearing of cylinder 116 is relatively close to the moving shear assembly. This reduces the moment arm length through which the transverse bending-induced shear loads act. The transverse loads on the bearing structure are thus reduced. Further, the center bolster provides a direct transfer of clamping load on the infeed side of the apparatus. This eli iates the tendency of the apparatus acting as a "knuckle press" which characterizes some prior art machines. From the foregoing, it will be observed that numerous variations and modifications may be effected without departing from the true spirit and scope of the novel concept of the invention. It is to be understood that no limitation with respect to the specific apparatus and method illustrated herein is intended or should be inferred. It is, of course, intended to cover by the appended claims all such modifications as fall within the scope of the claims. _ C'I

Claims: WHAT IS CLAIMED IS : 1. An improved method for shearing a bar comprising the steps of: clamping a first portion of said bar and restraining a first portion of said bar against movemen ; providing a movable force-transmitting means extending along and adapted for engaging at least first and second generally opposite surface regions of a second portion of said bar adjacent said first portion; engaging said bar on said first surface region of said second portion with said force-transmitting means; applying a first force against said first surface region generally normal to the longitudinal axis of the bar while simultaneously transmitting the resulting reaction force through said force-transmitting means to said bar on said second surface region of said second portion, said first force and said reaction force thus being exerted in opposing directions on said first and second surface regions, respectively, along said second portion of said bar generally perpendicular to the longitudinal axis of said bar to prevent bending of the second portion of the bar about the longitudinal axis of the bar relative to the first portion of the bar; and applying a second force to said force-transmitting means in a direction normal to the longitudinal axis of said bar sufficient to move said force-transmitting means engaged with said second portion of the bar relative to the clamped first portion of the bar thereby shearing the bar without substantially bending said second portion of the bar relative to said first portion of the bar. • 2. The method in accordance with claim 1 in - RIX Γ OMPI which said force-transmitting means includes a reaction cage and a clamp carried by, and movable relative to, said reaction cage and in which said step of engaging said bar on said first surface region of said second portion with said force-transmitting means includes the step of initially moving said clamp relative to said reaction cage and against said bar. 3. The method in accordance with claim 2 in which said step of applying said first force against said first surface region of said bar includes applying said first force through said clamp against said bar with the reaction force taken by said reaction cage and with said first force being sufficient to cause movement of said reaction cage relative to both said bar and engaged clamp whereby part of said reaction cage is forced against said second surface region of said bar. 4. The method in accordance with claim 101 in which said step of applying a second force to said force-transmitting means includes applying said second force to said reaction cage in a direction opposite to said initial relative movement of said clamp. 5. The method in accordance with claim 2 in which said step of initially moving said clamp against said bar includes forcing a wedge between said clamp and said reaction cage to urge said clamp towards said bar. 6. The method in accordance with claim 5 in which said step of forcing said wedge between said clamp and said reaction cage includes moving said wedge along a plane generally parallel to the longitudinal axis of the bar to be sheared. 7. An improved method for shearing a bar -^ comprising the steps of: providing a movable holder carrying a clamp which is movable relative to said holder; feeding a bar into said holder; restraining a first portion of said bar adjacent said holder against movement; moving said clamp relative to said holder against a first surface region of a second portion of said bar, said clamp being moved generally normal to the longitudinal axis of the bar; applying a first force through said clamp against said first surface region of said.bar with the reaction force taken by said holder and with said first force being sufficient to cause movement of said holder relative to both said engaged clamp and to said bar whereby part of said holder is forced against a second surface region of said bar generally opposite said first surface region, said first force and said reaction force thus being exerted in opposing directions on said first and second surface regions, respectively, along said second portion of said bar generally perpendicular to the longitudinal axis of said bar to prevent bending of said second portion of the bar about the longitudinal axis of the bar relative to the first portion of the bar; and applying a second force to said holder in a direction normal to the longitudinal axis of said bar sufficient to move said holder engaged with said second portion of the bar relative to the restrained first portion of the bar thereby shearing the bar without substantially bending the second portion of the bar relative to the first portion of the bar. OMPI 8. An apparatus for shearing a bar comprising: means for clamping a first portion of said bar and restraining a first portion of said bar against movement; a movable force-transmitting means adjacent said first portion clamping means, said force-transmitting means adapted for receiving a second portion of said bar adjacent said first portion with said second portion of said bar presenting at least first and second generally opposite surface regions within said force-transmitting means, said force-transmitting means being adapted to engage at least said second surface region of said second portion of said bar; a movable engaging member and means for moving said engaging member both carried by said force-transmitting means, said movable engaging member being movable relative to said force-transmitting means for engaging said bar on said first surface region of said second portion and for applying a first force against said first surface region generally normal to the longitudinal axis of the bar whereby the resulting reaction force is transmitted through said force-transmitting means to said bar on said second surface region of said second portion, said first force and said reaction force thus being exerted in opposing directions on said first and second surface regions, respectively, along said second portion of said bar generally perpendicular to the longitudinal axis of said bar to prevent bending of the second portion of the bar about the longitudinal axis of the bar relative to the first portion of the bar; and means for applying a second force to said O force-transmitting means in a direction normal to the longitudinal axis of said bar sufficient to move said force-transmitting means engaged with said second portion of the bar relative to the clamped first portion of the bar thereby shearing the bar without substantially bending said second portion of the bar relative to said first portion of the bar. 9. The apparatus in accordance with claims in which (1) said force-transmitting means includes a reaction cage and (2) said engaging member is a clamp member carried by, and movable relative to, said reaction cage. 10. The apparatus in accordance with claim 8 in which said means for applying a second force includes a hydraulically actuated piston adapted to move said reaction cage. 11. The apparatus in accordance with claims in which said engaging member is a clamp member, in which said force-transmitting means is a reaction cage, and in which said means for moving said engaging member relative to said force-transmitting means includes a wedge adapted to be moved between said clamp member and said reaction C3ge to urge said clamp towards said bar. 12. An apparatus for shearing a bar comprising: means for clamping a first portion of said bar and restraining a first portion of said bar against movement; a movable load transmitting holder adjacent said first portion clamping means, said holder adapted for being aligned in an initial bar loading position and receiving a second portion of said bar with said second portion of said bar presenting at least first and second generally opposite surface regions within said holder; a clamp carried on said holder and slidably movable relative thereto, said clamp having at one end a gripping surface for engaging said first surface region of said second portion of said bar, said clamp having at its other end an engageable planar surface; a wedge member having an engaging surface in sliding contact with said.clamp engageable planar surface; means carried on said holder for moving said clamp in said holder against said first surface region of said second portion of said bar and for subsequently applying a first force thereto whereby said holder is moved relative to both said clamp and bar to engage said second surface region of said second portion of said bar; and means for applying a second force to said holder in a direction normal to the longitudinal axis of said bar sufficient to move said holder and clamp engaged with said second portion of the bar relative to the restrained first portion of the bar thereby shearing the bar without substantially bending the second portion of the bar relative to the first portion of the bar. 13. The apparatus in accordance with claim 12 further including means for moving said holder in a direction opposite to the direction of said second force whereby said holder can be returned to its initial position after said bar has been sheared. 14. The apparatus in accordance with claim13 further including means for moving said clamp towards said wedge whereby initial clearance for said second portion of said bar can be provided. 15. The method of clamping one or two bars to be sheared in a bar shear machine on the infeed side of said machine wherein said machine has a guideway on the infeed side for receiving bars in end-to-end alignment, said method comprising the steps of: feeding at least one bar into said guideway; providing a stationary die to define a part of said guideway and adapted to engage a first surface region of at least one bar; providing a movable infeed clamp assembly on one side of said guideway opposite said stationary die, said assembly adapted to move between a retracted position providing clearance for said bars in said guideway opposite said stationary die and an extended position in engagement with a second surface region of the bar generally opposite said first surface region, said movable infeed clamp assembly including a support block and an infeed clamp, said infeed clamp being received on said support block for freely pivoting relative to said support block and having an engaging face adapted to be oriented at an angle relative to the longitudinal axes of said bars when said infeed clamp is pivoted in said support block; moving said infeed clamp assembly towards at least one of said bars from said retracted position to said extended position; and engaging said one bar with said engaging face of said infeed clamp and forcing said infeed clamp engaging face against the second surface region of the bar to force the first surface region of the bar against said stationary die whereby said infeed clamp can pivot on said support block in response to the reaction forces transmitted to the infeed clamp from the regions of contact with the bar to orient said infeed clamp at an angle relative to the longitudinal axis of said bar and in contact with said bar in at least two longitudinally spaced-apart regions along said bar. 16. The method in accordance with claimlS in which said step of feeding at least one bar into said guideway includes feeding two bars of differeing diameters in end-to-end alignment with adjacent ends. abutting and then positioning the abutting ends of said two bars in said guideway between said stationary die and said infeed clamp. 17.. The method in accordance with claim15 in which said step of engaging at least one of said bars with said engaging face of said infeed clamp includes engaging a region of each bar whereby said infeed clamp is pivoted in said support block at an angle relative to the longitudinal axes of said bars. 18. In a bar stock shearing machine having a guideway on the infeed side for receiving bars in end-to-end alignment, an improvement for clamping one or two bars to be sheared on the infeed side of said machine, said improvement comprising: a stationary die defining a part of said guideway and adapted to engage a first surface region of at least one bar; a movable infeed clamp assembly on one side of said guideway opposite said stationary die, said assembly adapted to move between a retracted position providing clearance for said bars in said guideway opposite said stationary die and an extended position in engagement with a second surface region of the bar generally opposite said first surface region, said movable infeed clamp assembly including a support block and an infeed clamp, said infeed clamp being received on said support block for freely pivoting relative to said support block and having an engaging face adapted to be oriented at an angle relative to the longitudinal axes of said bars when said infeed clamp is pivoted in said support block; and means for moving said infeed clamp assembly toward and against at least one of said bars from said retracted position to said extended position whereby said infeed clamp engaging face is forced against the second surface region of the bar to force the first surface region of the bar against said stationary die and whereby said infeed clamp can pivot on said support block in response to the reaction forces transmitted to the infeed clamp from the regions of contact with the bar to orient said infeed clamp at an angle relative to the longitudinal axis of said bar and in contact with said bar in at least two longitudinally spaced-apart regions along said bar. 19. The improvement in accordance with claim 18 in which said support block has a partially cylindrical concave bearing surface and in which said infeed clamp has a partially cylindrical convex bearing surface received on said support block concave bearing surface. 2 Q :. T e improvement in accordance with claim 18 in which said means for moving said infeed clamp assembly includes at least one wedge member adapted to be moved relative to and against said support block. 21. The improvement in accordance with claim 18 further including spring bias means for urging said infeed clamp assembly away from said guideway whereby initial clearance is provided between said infeed clamp assembly and a bar in said guideway. 22. In a bar stock shearing machine having first and second end bolsters, a center bolster, a hydraulic cylinder positioned between said first end bolster and said center bolster, tie rods securely joining all the bolsters and maintaining the hydraulic cylinder and bolsters in fixed position, a fixed die and a movable die adapted to receive a bar and disposed between said center bolster and said second end bolster, said movable die adapted to be moved relative to said fixed die by said hydraulic cylinder between said center and second end bolsters to shear said bar, the improvement comprising: a plurality of retainer plates extending between said center bolster and said second end bolster and defining a die receiving cavity around said fixed die and said movable die for restraining said dies against movement resulting from the reaction forces generated during the shearing of the bar, the assembly of said retainer plates, center bolster and second end bolster together defining a die housing, each said retainer plate having two ends with one end being adjacent said center bolster and with the other end being adjacent said second end bolster, each end of each said retainer plate defining therein a key cavity; said center bolster and said second end bolster each defining therein key cavities in alignment with and facing the key cavities of said retainer plates; and a plurality of key members, each said key member inserted and interfitted partially in a retainer plate key cavity and partially in an aligned bolster key cavity, thereby providing an interlocking construction which eliminates bolts and welds joining the retainer plates and bolsters, said interfitted keys and key cavities thus forming the only joints within the retainer plate and bolster assembly defining the die housing and serving to bear the component forces normal to direction of the movement of the movable die which result from the shearing of the bar. 23. The improvement in accordance with claim 22in which said machine has 1) an infeed side and an outfeed side, and in which said plurality of retainer plates includes a bottom retainer plate extending from the infeed side to the outfeed side, 2) an upper infeed retainer plate disposed above said bottom retainer plate on the infeed side of said shearing machine, and 3) an upper outfeed retainer plate disposed above said bottom retainer plate on the outfeed side of said shearing machine. 24. The improvement in accordance with claim 23 in which each said retainer plate has at least one bore extending therethrough for receiving one of said tie rods. • 25. The improvement in accordance with claim 24 in which said machine has an infeed side and an outfeed side, in which one of said retainer plates is a bottom retainer plate extending from the infeed side of said machine to the outfeed side of said machine, and in which said bottom retainer plate defines two spaced apart bores therethrough, each said bore adapted to receive one of said tie rods, said bottom retainer plate further defining two of said key cavities at each end, one cavity adjacent each bore and partially defined thereby.

Inventors: LAZAR J, SHVARTSMAN B
Applicants: SLUGGER CORP
Application year: 1980
Main classification: B23D23
IPC codes: B23D23, B23D33