US3820426A

US3820426A - Wide throat scrap shear

Info

Publication number: US3820426A
Application number: US00299798A
Authority: US
Inventors: W Thompson
Original assignee: Harris Press and Shear Corp
Current assignee: American Hoist and Derrick Co; Harris Waste Management Group Inc
Priority date: 1972-10-24
Filing date: 1972-10-24
Publication date: 1974-06-28
Anticipated expiration: 1991-06-28

Abstract

A scrap metal shear has the opposite ends of its crosshead slidably guided, which carries a straight cutting blade cooperating with a horizontal fitted blade, for vertical movement and pivotally connected to depending hydraulic rams which, in turn, are pivotally mounted on the shear frame so that either end of the crosshead may be moved up or down relative to the other end by differential operation of the rams and the crosshead may be translated vertically while in an angular position to the horizontal by operation of both rams in unison. The shear also includes a hold-down device or clamp member mounted and operable by another set of rams similar to the mounting and operation of the crosshead.

Description

United States Patent 191 Thompson June 28, 1974 WIDE THROAT SCRAP SHEAR 3,710,665 1/1973 Eddy 83/636 x 7 l Wall M. Th C d l nvntor ace ompson or e 6 Ga Primary Examiner-Andrew R. .luhasz [73] Assigneez Harris Press & Shear Corporation, Assistant E i w D B C Attorney, Agent, or FirmCushman, Darby & 22 Filed: Oct. 24, 1972 Cushman [211 App]. No.: 299,798 ABSTRACT US. Cl 813/113, 83/554, 83/624,

A scrap metal shear has the opposite ends of its cross- [52] 83/636 100/98 R head slidably guided, which carries a straight cutting [51] I t B26d 1/06 blade cooperating with a horizontal fitted blade, for l 58] d B83 375 vertical movement and pivotally connected to dependle 6' 'gz 554 6 6 ing hydraulic rams which, in turn, are pivotally 83/6H mounted on the shear frame so that either end of the 85/51 3 62 crosshead may be moved up or down relative to the other end by differential operation of the rams and the 1 crosshead may be translated vertically while in an an- [56] References cued gular position to the horizontal by operation of both UNITED STATES PATENTS rams in unison. The shear also includes a hold-down 3,126,816 3/1964 Thompson 100/98 R device or clamp member mounted and operable by 3,l36,l93 6/l964 Gantz 83/644 X another set of rams imilar to the mounting and pera- 3,183,756 5/1965 Deh n 1 on fth crosshem 3,316,791 5/1967 Greis et al.. 3.491.643 1/1970 Meinholdt 83/636 X 13 Claims, 15 Drawing Figures 44? Q a A 98 I H] 28 F. 5 r4 7a- ---':;:l r ;1 I

7 O l 1 L40 20 I I ogo ore o To 050 o o U1 1 64 l M 76 36 76' k 74' /88 88 l 7 l 75 4 2 40 7a 1 y 24 0 0'0 0'0 0'0 olo olo olo o M l l l I L42 l /26 l V l l a l l I N l 34 1 I l 1 1 I PATENTEnJuuzs I974 SHEEI 1 0F 8 PATENTEU JUN 2 8 I974 SHED 2 [IF 8 m miumza I974 820 426 sum 3 BF 8 PATENTED H I974 3.820.426 sum 7 are WIDE THROAT SCRAP SHEAR This invention relates to scrap metal shears and, more especially, to a shear for cutting into smaller pieces very large bulky pieces of scrap, such as portions of freight cars, ship plates, etc. Such bulky scrap pieces may be quite large, i.e., having their width and length dimensions, respectively, of the possible order of from 20 to 80 feet. A shear for cutting such large pieces of scrap is known as a wide-throat shear.

In order to cut such large pieces of scrap in conventional narrow-throat shears, the pieces usually must be initially cut by hand, e.g. as by a torch, into much smaller pieces to enable passage through the shear. The labor involved in cutting such large pieces of scrap down to much smaller sizes for shearing renders the entire operation quite expensive. While it is possible to make conventional scrap .metal shears in sizes large enough to cut very large pieces of scrap, the great expense of such larger shears, of conventional types, renders them uneconomical. By conventional narrowthroat shears, reference is made, for example, to the socalled guillotine type scrap metal shear which has a horizontal fixed cutting edge or blade with which cooperates a vertically movable blade having a fixed angle of inclination, usually of the order of with respect to the horizontal blade. Examples of such shears are disclosed in US. Pat. Nos. 3,126,817 and 3,332,342.

Accordingly, it is an object of this invention to provide an improved wide-throat scrap metal shear, that can be fabricated and operated economically, for shearing large bulky scrap of the order of from 8 to feet in width, 3 to 5 feet in depth, and 40 to 80 feet in length. A practical economical shear with the ability to cut large bulky pieces of scrap having dimensions of the order referred to above, reduces overall processing and shearing costs by reducing the cost of manually cutting large bulky scrap to the small sizes which can be cut to marketable sizes in conventional scrap metal shears. For example, sheared scrap pieces cut in a scrap metal shear embodying this invention may range from 18 to 24 inches in width by 8 to 20 feet in length. Scrap metal pieces of this size can be practically and efficiently handled for transverse severing in a narrow-throat shear in order to reduce such scrap pieces to market grade sizes.

Another object of the invention is to provide a scrap metal shear for cutting large bulky scrap which has a reduced shearing stroke in comparison with a conventional guillotine shear of comparable size.

It is another object of this invention to provide a shear for shearing large bulky scrap pieces in which its largest component, i.e., its frame, is of a size that can v be transported with conventional commercial means,

such as railroads and highway trucks.

It is another object of this invention to provide a scrap metal shear of the type described wherein the shearing angle is variable and also reversible in order to enable the shearing forces to be shifted to a location of less resistance in the event stalling or blocking resistance is encountered in one location.

It is another object of this invention to provide an improved hold-down means or clamping device for use with a wide-throat scrap metal shear which will conform to the upper surface of the scrap metal being sheared in order to more effectively perform its holddown and clampingfunctions.

Another object of the invention is to provide an improved wide-throat scrap metal shear which is economical to construct and to operate and which reduces the volume of hydraulic fluid necessary for operation in comparison with a conventional guillotine shear of comparable size.

It is a further object of this invention to provide an improved design for a wide-throat shear in which increases in throat width do not require proportionate increases in frame height or maximum shearing stroke.

' Other objects and advantages of the invention will become apparent from the following description and accompanying drawings in which:

FIG. 1 is a front elevational view of a scrap metal shear embodying this invention.

FIG. 2 is a vertical sectional view taken substantially on line 22 of FIG. 1. 7

FIG. 3 is a fragmentary plan view of a righthand portion of the shear shown in FIG. 1.

FIG. 4 is a fragmentary horizontal sectional view taken substantially on line 4-4 of FIG. 2.

FIGS. 5, 6 and 7 are diagrammatic front elevational views of the shear shown in FIG. 1 illustrating successive positions of the movable blade in a typical shearing cycle.

FIGS. 8, 9, l0 and 11 are diagrammatic front elevational views of the shear shown in FIG. 1 illustrating successive positions of the movable blade in a typical shearing cycle wherein a stalling or blocking shearing resistance is encountered.

FIG. 12 is a rear elevational view of a shear embodying this invention showing a simplified modified form of a hold-down or clamping device.

FIG. 13 is a fragmentary vertical sectional view taken substantially on line l3--l3 of FIG. 12.

FIG. 14 is a diagram of the hydraulic controls for a shear embodying this invention.

FIG. 15 is a graph of the distribution of cutting forces, achievable with a given hydraulic pressure, along the length of the cutting blades of a shear embodying this invention.

Referring now to FIGS. 1 to 4 of the drawings there is shown a scrap metal shear having a frame composed of a pair of spaced upright side column structures 20 interconnected by a transverse top structure 22 and by a lower bed 24 supported on a base structure 26. The bed 24, column structures 20 and base structure 26 are welded together while the top structure 26 preferably is secured to the side columns by cap screws 28 so as to be detachable for shipping purposes. The bed 24 is a rugged metal slab generally U-shaped with an elongated preferably straight base portion 30, in plan view, supported by flanges 32 upstanding from a base plate 34 of the base structure. The bed 24, column structures 20, and a movable crosshead 36 define the throat 38 of the shear through which scrap to be sheared is advanced in the direction of the arrow shown in FIG. 2.

Removably secured in an appropriate recess in the upper forward edge of the bed 24 is a hardened bar forming a fixed blade 40 that is rectangular in transverse section and defines, at the comer between its upper and front surfaces, a fixed horizontal cutting edge 42. Preferably, the bed 24 is provided, between the column structures 20, with a wear plate 44 flush with the upper surface of the bar 40. The rearward end of the bed 24 is adapted to be disposed at the forward open end of a conventional scrap metal feeding trough (not shown) like those disclosed, for example, in US.

Pat. Nos. 3,126,817 and 3,332,342. Such feeding troughs usually are provided, at their rearward ends, with a feeding ram for moving scrap out of the trough and across the shear bed 24 in the direction of the arrow to a shearing position wherein the scrap extends a predetermined distance beyond the fixed cutting edge 42.

The crosshead 36 has its sides or ends mounted for vertical reciprocating and rocking movements within vertical guideways 46 located on the opposed sides of the upright side column structures 20. The crosshead 36 as a flat rear face 48 and a flat lower face. Removably secured in a recess at the corner of these faces is a hardened bar, rectangular in cross section, forming a movable blade 52 defining a movable cutting edge 54 cooperate with the fixed cutting edge 42 for shearing scrap. The crosshead 36 includes a massive lower cross member 56 which carries the blade 52, a plate-like member 58 which extends vertically from the cross member 56 immediately above the blade 52, an upper cross member 60, and a plurality of upright stiffening and strengthening webs or plates 62 extending between the upper and lower cross members in front of the vertical member 58.

The member 58 is extended at both ends, as shown in FIGS. 3 and 4, between and laterally beyond the guideways 46 and arranged to form one of a pair of spaced ears 63, the other being formed by a plate-like member secured to the crossahead 36 in front of and parallel to the member 58. Mounted in trunions 64 on the top frame structure 22 at each side thereof, for pivotal movement transversely of the throat 38 are the cylinders 66 of a pair of double-acting hydraulic rams 68. The piston rods 70 of the rams 68 are connected to the crosshead 36 by pivot pins 72 extending through the corresponding aforesaid ears 63 and through end portions of the rods.

From this construction it will be seen that the rams 68 can be operated in unison to vertically reciprocate the movable blade 52, can be operated differentially to pivot the movable blade through a relatively wide range of shearing angles relative to the fixed blade 40, and also can be operated in unison to reciprocate the movable blade while in an inclined position relative to the fixed blade.

Depending from the crosshead 36, at each side thereof and within the guideways 46 is a leg 74 having a downwardly and laterally outwardly inclined inner face 76. This inner face 76 pushes scrap laterally inwardly of the throat 38 during a shearing stroke to minimize possible interference of scrap with the outer side walls of the guideways 46 as the scrap is advanced into position for another shearing cut.

Portions of the opposed inner sides of the upright side column structures 20, forwardly of the guideways 76, are adapted to receive lateral components of the shearing resistance reaction forces on the crosshead 36, as later explained. For this purpose these side portions are provided with vertically extended wear plates constituting slideways 78. Each side of the lower cross member 56 of the crosshead 36 is provided with a thrust-transmitting member 80 opposed to the corresponding slideway 78. The members 80 are provided with wear plates 82 and are pivotally connected to the crosshead 36, as by cars 84 and a pivot pin 86, for rocking movement transversely of the throat 38. When the crosshead 36 is in a horizontal position, as shown in FIG. 1, the members 80 are slightly spaced from the slideways 78. It will be seen, however, that when the movable shearing blade 52 is inclined relative to the fixed blade 40 and is effecting a shearing stroke against scrap, the shearing resistance will develop reaction forces on the crosshead 36 which will have a lateral component in the direction of the lower side of the crosshead. This will urge the crosshead 36 laterally toward the lower side thereof so that the corresponding thrust-transmitting member 80 will engage the corresponding slideway 78. Thus, lateral components of reaction forces on the crosshead 36 will be transmitted to the upright column structures 20 of the frame rather than to the rams 68. Consequently, the piston rods of the rams 68 are relieved of possible bending stresses.

Preferably, the spaces between the

opposed wear plates

82 and 78 on the members and on the upright side members 20, respectively are overlapped, on their rearward sides by upright flanges 88 on the column structures 20 having inwardly and forwardly inclined surfaces. These surfaces divert advancing scrap inwardly to keep it out of the spaces between the op posed

wear plates

78 and 82.

Rearwardly of the guideways 46, the opposed inner sides of the upright column structures 20 are provided with an additional set of guideways 90. Mounted for vertical reciprocating and rocking movements in these guideways 90 is a clamp member or a hold-down device 92 having a substantially flat undersurface. The clamp member 92 is vertically reciprocable and rockable by a pair of hydraulic rams 94 having their cylinders 96 mounted in trunions 98 on the frame top structure 22, adjacent each side thereof, for rocking movement transversely of the throat 38. The piston rods 100 of the rams 94 are pivotally connected to the clamp member 92, as by pivot pins 102 and ears 104, for relative movement about axes parallel to those of the trunions 98. It thus will be seen that the rams 94 can be operated to force the clamp member 92 downwardly against scrap to be sheared and hold the latter against the bed 24 to prevent inefiicient displacement during a shearing operation. It also will be seen that the clamp member 92 can be arranged in an inclined position to conform itself to the upper surface of the scrap. This clamp member 92 can also be used to crush or compact scrap against the bed 24 so that it will be in a better condition for being sheared by the movable blade 52.

At the lower end of each clamp member guideway 90 there is fixedly mounted to the bed 24 and to the corresponding side column. structure 20 the cylinder of a horizontally disposedtransversely extending two-way hydraulic ram 106 having its piston rod extendable inwardly toward the throat 38. The piston rod of each ram 106 has connected thereto a generally rectangular head 108 receivable, when the ram is retracted, within the corresponding guideway 90 so that the outer surface of the head will be flush with the opposed lead-in portions 110 of the inner surfaces of the upright column structures 20. During a shearing operation or a clamping operation wherein the clamping head 92 and- /or the cross head 36 is disposed at an angle to the bed 24, it is possible for scrap to become wedged tightly against the inner surfaces of the upright column structures 20. This wedging action may be so great as to impart an undue load on the feeding ram (not shown) which advances scrap to be sheared from the feed trough (not shown) through the throat 38 of the shear. If this occurs the corresponding ram 106 may be operated to move its head 108 against the wedged scrap and push the latter away from wedging engagement against the corresponding side of the column structure in order to free the scrap for advancement by the feeding ram.

The above-described scrap metal shear is designed to be made in various sizes, for example one with a throat 38 that is 8 feet wide and 2 feet deep with a total shearing force of 700 tons to be applied on the crosshead 36 by the two hydraulic rams 68, or with a throat that is 12 feet wide and 3 feet deep with a total shearing force of 900 tons.

Referring now to FIG. 14 there is shown a preferred type of hydraulic system for a shear embodying this invention. The two rams 68 are selectively individually or both supplied with hydraulic fluid under high pressure selectively by either or both of two fixed displacement hydraulic pumps P, and P which draw hydraulic fluid from a reservoir R and deliver it to control valves V, and V, respectively. The supply pressure of the pumps is limited, for example to 2,400 psi, by appropriate pressure relief valves V,,, interposed in the lines between the pumps P, and P and their respective control valves V, and V,,. For reasons later apparent, the pumps P, and P are protected against backflow at pressures higher than their limited supply pressure by check valves V interposed in'the supply lines between the relief valves v,, and the control valves V and V The control valves V, and V are adapted to return fluid to the reservoir R or selectively deliver it respectively to four-way control valves V or V one for each ram 68, and to four-way control valves V or V one for each ram. The control valves V V V and V selectively supply orexhaust fluid to or from the opposite ends of their respective rams 68. For reasons later described, pressure relief valves V are connected to the lines connecting the valves V V V and V with the upper ends of their respective rams 68. These relief valves V, are set to open at a higher pressure than the maximum pressure of the fluid supplied by the pumps P, and P As an example, if the supply pressure is limited to 2,400 psi, the relief valves V are set to open at 3,000 psi.

OPERATION In operation of the shear, the crosshead 36 preferably is withdrawn by its two hydraulic rams 68 to its uppermost horizontal position, as shown in FIG. 1. At this time scrap is advanced by the feeding ram (not shown) from the feed trough (not shown) through the throat 38 of the shear to extend beyond the fixed cutting edge 42 for a selected predetermined distance, such as 18 to 24 inches. Next the rams 94 are actuated to move the clamp member 92 downwardly into compressive engagement with the scrap to be sheared. As described above, the clamp member 92 not only will compress the scrap into a better condition for shearing, but also will conform to the upper surface of the scrap bundle and hold it tightly against the bed 24 so that it can be sheared more efficiently.

Next, one of the rams 68 for the crosshead 36 is operated to move the corresponding side of the crosshead downwardly, while the other ram is fixed against movement. This operation may be accomplished rapidly by supplying the moving ram 68 with hydraulic fluid from both pumps P, and P by operation of the control valves V, and V, and the control valves, e.g., V and V for the moving ram. This operation is continued, with possibly some shearing of scrap, until the movable cutting blade 52 assumes an angle of the order of about 10 with the fixed cutting blade 40, as shown in FIG. 5. This cutting angle has been found in practice to provide the most efficient results for further cooperating shearing action between the movable blade 52 and the fixed blade 40. After the shearing head 36 has assumed the aforesaid shearing angle of the order of 10, both rams 68 are operated in unison, to translate the crosshead 36 downwardly while maintaining this angle of inclination to shear scrap extending beyond the fixed cutting edge 42. Downward movement of both rams 68 in unison for a shearing operation preferably is accomplished by supplying each ram individually with hydraulic fluid from a single source, e.g., pump P or P by appropriate operation of the valves V, and V to better maintain the desired shearing angle of the order of l0. Supply from a common source might lead to angle variations due to variations in shearing resistance along the length of the blade 52 with consequent possible variation in movement rates of the two rams. The downward movement of the rams 68 is continued, with the crosshead 36 maintained in this fixed angular position until a considerabe amount, approaching half, of the length of the movable cutting edge 54 is disposed below the fixed cutting edge 42, as shown in FIG. 6. At this time, a considerable amount of the scrap extending beyond the fixed blade 40 will have been sheared off. Next the ram 68 connected to the lower end of the crosshead 36 is fixed in position, i.e., by valves V and V while the other ram 68 is extended downwardly to thereby complete the shearing of all of the scrap extending beyond the fixed blade 40, as shown in FIG. 7.

In this connection, it will be noted that as the mov able blade 52 is thus pivoted downwardly about its lower side, and the shearing of the scrap takes place progressively from a location approaching the midpoint of the fixed cutting edge 42 toward one side thereof, the shearing angle between the two blades decreases from an angle of the order of 10 to an angle of the order of about 5, all of which will accomplish effective shearing.

During a shearing operation the movable blade 52 may encounter sufficient shearing resistance to stall the rams 68 and thus block further downward movement of the crosshead 36. Such blocking resistance normally would be encountered while the crosshead 36 is being moved downwardly at a fixed shearing angle of the order of l0, and a large portion of such resistance normally would be encountered adjacent the down side of the movable blade 52 where most of the shearing has been effected. For example, referring to FIGS. 8 to 11, there are shown three large diameter scrap pipe sections S arranged on the bed 24 of the shear and projecting somewhat beyond the fixed cutting edge 42 in position for shearing. As explained above, the first step of the cutting operation will be to move one side, e.g., the left-hand side, of the movable cutting blade 52'downwardly to an angle of approximately 10 with respect to the fixed cutting blade 40 by operation of the valves V, and V,, as shown in FIG. 9. The next operation will be to translate the movable cutting blade 52 vertically downwardly while maintaining the aforedescribed shearing angle of approximately 10 by operation of valves V and V.,, as shown in FIG. 10. It is during this cycle of operation that the greatest shearing resistance will be encountered, particularly in shearing the scrap at the down side of the movable cutting blade 52, i.e., the left-hand side as shown in FIG. 10. Such resistance may be sufficient to stall or block the ram, effecting the downward movement of the movable cutting blade 52 at the left-hand side, against further movement with the available pump pressure, e.g., 2,400 psi.

The shearing resistance at the right-hand side, however, at this time normally will not be sufficient to stall or block the ram effecting downward movement of the movable cuttingblade 52 at the right-hand side. Accordingly, the right-hand side of the movable cutting blade normally will continue to move downwardly to shear scrap, with the angle of the movable cutting blade constantly changing and the pressure of the hydraulic fluid moving the ram constantly increasing. Under these conditions the right-hand ram will tend to pivot the blade 52 about a fulcrum located at the highest shearing resistance along the length of the blade, e.g., at F as shown in FIG. 10. This will, of course, increase the pressure in the top end of the left-handram 68 above'2,400 psi. The check valve V for whichever pump P or P which is supplying pressure fluid to this ramprevents damage to the corresponding pump from such increased pressure and the relief valve V for this ram opens if the pressure becomes excessive, e.g., 3,000 psi. With-the left-hand ram 68 thus stalled, the right-hand ram obtains a lever advantage so that the force exerted on the scrap by the blade 52 is greater than that obtainable when both rams are moving the blade down.

The ram effecting downward movement of the blade 52 at the righthand side may, however, encounter sufficient shearing resistance to stall it as well.

When these conditions are encountered, either or both of the rams 68 are operated by their respective valves V or V and V or V to retract the movable blade 52 upwardly and to cause it to assume an opposite angle of the order of 10, whereupon both rams are operated to move the movable blade downwardly while in this reversely angled position, as shown in'FIG. 11. During this movement the movable blade 52 normally will encounter shearing resistance only on the righthand portion thereof where the scrap has not been extensively cut, and normally this resistance will be less than the stalling resistance encountered as described above. Thus, the scrap on the right-hand portion of the bed 24 normally can be sheared off before the movable blade 52 encounters the partially cut scrap on the lefthand portion. At this time, however, since some of the shearing resistance will have been eliminated, the rams 68 will have sufficient force to cut off this partially cut scrap with less difficulty. Thus, blocking conditions can readily be overcome by a shear embodying this invention.

One of the greatest advantages of a shear embodying this invention is that shearing forces can be exerted that are greater than the forces obtainable from shearing operations when both rams are moving the movable cutting blade. This is demonstrated by an inspection of the graph shown in FIG. 15. This graph shows the distribution of shearing forces obtainable across the throat of a shear embodying this invention having a) a throat 12 feet wide and 3 feet high at maximum opening, b) rams supplied with hydraulic fluid at a pressure sufficient to develop a ram force in each of 455 tons, and c) relief valves for the top ends of the rams to limit their force under stalling conditions to 665 tons.

It will be seen that at each side of the throat a shearing force of about 480 tons can be developed when both rams are moving. This shearing force progressively increases inwardly from each side until at the center of the throat a shearing force can be obtained about equal to the combined maximum forces of both rams. On the other hand, if one ram stalls and the other continues to move, it will be seen that shearing forces are obtainable greater than when both rams are moving. This is due to the leverage advantage, described above, when one ram does not move.

Other advantages also are had. Thus, for example, a 900 ton shear embodying this invention which has a throat 3 feet high and 16 feet wide, is 25 feet wide and 15.6 feet high. In contrast, a conventional guillotine shear, having a movable cutting blade arranged at a fixed angle with respect to the fixed cutting blade and which has a throat that is 16 feet wide and 3 feet high at the side of the throat of least height, is 24 feet wide, but 27.17 feet high. Moreover, a shear of the aforesaid size embodying this invention would have a shearing stroke of the order of 55 inches, whereas a guillotine shear of comparable size would have a shearing stroke of the order of 71 inches. This greater stroke for the guillotine shear is necessitated by the act that the higher side of the movable cutting blade must be moved through a greater distance than the lower side in order to effect a complete cutting stroke. A greater shearing stroke, of necessity, requires a greater oil capacity.

It also has been found that increases in size of throat width for a constant throat height of shears embodying this invention does not require comparable increases in frame height or stroke length. For example, a shear embodying this invention having a throat 3 feet high and 16 feet wide has a frame height, excluding the detachable top frame member, only 13 inches higher and a stroke only 6 inches greater than a shear embodying this invention having a throat 3 feet high and 12 feet wide.

Referring now to FIGS. 12 and 13, there is shown a modified simplified form of a hold-down or clamping device embodying this invention. In this arrangement a transverse clamp member 112 is fioatingly supported from a frame top cross member 22' above the bed 24 by two depending double-acting hydraulic rams 116. The rams 116 are connected to the top frame member 22 and to the clamp member 112 by universal joints.

In the arrangement shown the cylinders 118 are connected to overhanging brackets 120 on the top frame member 22' by ball and socket joints 112, while lower ends of the piston rods 124 are pivotally connected to a clamp-member-supporting element 126 by a pin and ear arrangement 128 which permits relative pivotal movement about axes generally parallel to the direction of advancement of the scrap to be sheared. The elements 126 are, in turn, connected to the clamp member 112 for pivotal movement about axes transverse of the bed 24'.

Preferably, the hold-down or clamp member 112 is formed of two front and rear transversely extending

bars

130, 132 arranged at an upwardly converging angle, and a generally flat bar 134 interconnecting the front and rear bars adjacent the lower edges of the latter. The bars are connected, adjacent their sides, by ear-like elements 136 which pivotally receive the supporting elements 126. In operation of this modified form of clamping member, it will be seen that the rams 116 can be extended to urge the clamping member 112 downwardly against scrap to be sheared, and that the following support of the member by the rams enables the member to conform most readily to the upper surface of a scrap bundle to be sheared.

It thus will be seen that the objects of this invention have been fully and effectively accomplished. It will be realized, however, that the foregoing specific embodiments have been shown and described only for the purpose of illustrating the principles of this invention and are subject to change without departure from such principles. Therefore, this invention includes all modifications encompassed within the spirit and the scope of the following claims.

What is claimed is:

1. A scrap metal shear comprising:

a generally horizontal bed having at one end thereof a fixed cutting blade across which scrap to be sheared advances,

upright side column members secured to said bed,

one at each side thereof, defining opposed channellike upright side guideways,

a crosshead mounted for vertical reciprocating and rocking movements in said guideways and having a movable cutting blade cooperative with said fixed cutting blade, said bed, column members, and crosshead when the latter is in its uppermost position defining a throat through which scrap to be sheared advances,

hydraulic ram means mounted at the upper end of each of said column members for pivotal movement transversely of said throat and connected to the adjacent side of said crosshead for relative pivotal movement transversely of said throat, whereby by selective differential operation of said ram means, said movable cutting blade may be oppositely inclined for shearing cooperation with said fixed cutting blade.

2. The structure defined in claim 1 including means defining an extended upright slideway on each of said column members facing said throat and a thrust pad pivotally mounted on said crosshead at each side thereof closely adjacent and in opposition to the corresponding slideway for engagement therewith by a lateral component of shearing resistance reaction forces on the crosshead.

3. The structure defined in claim 1 in which the column members define second opposed upright channellike side guideways on that side of the first guideways remote from the fixed cutting blade, clamp-like holddown means mounted in said second guideways for vertical reciprocating and rocking movements, and second hydraulic ram means mounted at the upper end of each of said column means for pivotal movement transversely of the throat and connected to the adjacent side of said hold-down means for relative pivotal movement transversely of said throat, whereby said hold-down means can conform to the transverse configuration of the upper surface of scrap to be sheared.

4. The structure defined in claim 3 including third bydraulic ram means mounted adjacent the lower end of each of said second guideways for extension transversely inwardly of the bed, and a head on each of the said third ram means for laterally engaging scrap on said bed.

5. The structure defined in claim 1 including pump means of predetermined maximum pressure for supplying pressure fluid to the ram means, check valves in the supply lines for the fluid for preventing back flow therein to said pump means, and pressure relief valves in the supply lines to the upper ends of said ram means for relieving pressure therein over a predetermined pressure greater than said pump maximum pressure, whereby if shearing resistance is encountered at a loca tion along the length of the movable cutting blade sufiicient to stall one of said ram means, the other of said ram means will exert a shearing force at said location greater than the force developable thereat when the crosshead is being moved downwardly by both of said ram means.

6. The structure defined in claim 5, in which the pump means includes two independent pump means and control valve means for supplying pressure fluid to each of the ram means selectively from either or both of the independent pump means.

7. A method of shearing scrap metal with a scrap metal shear which includes a generally horizontal bed having at one end thereof a fixed cutting blade across which scrap to be sheared advances,

upright side column members secured to said bed,

one at each side thereof, defining opposed channellike upright side guideways,

hydraulic ram means mounted at the upper end of ach of said column members for pivotal movement transversely of said throat and connected to the adjacent side of said crosshead for relative pivotal movement transversely of said throat, whereby by selective differential operation of said ram means, said movable cutting blade may be oppositely inclined for shearing cooperation with said fixed cutting blade, starting from a position wherein the crosshead is in a horizontal position above scrap to be sheared, the steps comprising:

a. advancing one of the ram means downwardly while maintaining the other stationary until the movable cutting blade is inclined at a preselected angle to the fixed cutting blade, and i b. advancing both ram means downwardly in unison to shear scrap.

8. The method defined in claim 7 including the further sequential steps of continuing to advance both rams downwardly in unison to shear scrap until approximately one-half of the length of the movable cutting blade is below the fixed cutting blade, and

maintaining the one ram means stationary while advancing the other downwardly to shear scrap until substantially the entire movable cutting blade is below the fixed cutting blade.

9. The method defined in claim 8 including the further sequential step of retracting both ram means to their starting positions in preparation for another shearing operation.

10. The method defined in claim 7 in which the preselected angle is of the order of 10.

11. A method of shearing scrap metal with a scrap metal shear which includes a generally horizontal bed having at one end thereof a fixed cutting blade across which scrap to be sheared advances,

upright side column members secured to said bed,

one at each side thereof, defining opposed channellike upright side guideways,

hydraulic ram means mounted at the upper end of each of said column members for pivotal movement transversely of said throat and connected to the adjacent side of said crosshead for relative pivotal movement transversely of said throat, whereby by selective differential operation of said ram means, said movable cutting blade may be oppositely inclined for shearing cooperation with said fixed cutting blade, starting from a position wherein the crosshead is in a horizontal position above scrap to be sheared, the steps comprising:

a. advancing one of the ram means downwardly while maintaining the other stationary until the movable cutting blade is inclined at a preselected angle to the fixed cutting blade,

b. advancing both ram means downwardly in unison to shear scrap until blocking shearing resistance is encountered by both ram means,

c. retracting either or both ram means to cause the movable cutting blade to be inclined at an opposite preselected angle to the fixed cutting blade, and

d. advancing both ram means downwardly in unison to shear scrap.

12. A method of shearing scrap metal with a scrap metal shear which includes a generally horizontal bed having at one end thereof a fixed cutting blade across which scrap to be sheared advances,

upright side column members secured to said bed,

one at each side thereof, defining opposed channellike upright side guideways,

a crosshead mounted for vertical reciprocating and rocking movements in said guideways and having a movable cutting blade cooperative with said fixed cutting blade, said bed, column members, and crosshead when'the latter is in its uppermost position defining a throat through which scrap to be sheared advances,

hydraulic ram means mounted at the upper end of each of said column members for pivotal movement transversely of said throat and connected to the adjacent side of said crosshead for relative pivotal movement transversely of said throat, whereby by selective differential operation of said ram means, said movable cutting blade may be oppositely inclined for shearing cooperation with said fixed cutting blade, starting from a position wherin the crosshead is in a horizontal position above scrap to be sheared, the steps comprising:

b. advancing both ram means downwardly in unison until blocking shearing resistance is encountered by one of said ram means, and

c. continuing to advance the other of said ram means downwardly to shear scrap.

13. A method of shearing scrap metal with a scrap metal shear which includes a generally horizontal bed having at one end thereof a fixed cutting blade across which scrap to be sheared advances,

upright side column members secured to said bed,

one at each side thereof, defining opposed channellike upright side guideways,

b. advancing both ram means downwardly in unison until blocking shearing resistance is encountered by one of said ram means,

c. continuing to advance the other of said ram means downwardly to shear scrap until blocking shearing resistance is encountered by the other ram means,

d. retracting both rain means to the starting position,

e. advancing the other of the ram means downwardly while maintaining the one stationary until the movable cutting blade is inclined at an opposite preselected angle to the fixed cutting blade, and

f. advancing both ram means downwardly in unison to shear scrap.

Claims

1. A scrap metal shear comprising: a generally horizontal bed having at one end thereof a fixed cutting blade across which scrap to be sheared advances, upright side column members secured to said bed, one at each side thereof, defining opposed channel-like upright side guideways, a crosshead mounted for vertical reciprocating and rocking movements in said guideways and having a movable cutting blade cooperative with said fixed cutting blade, said bed, column members, and crosshead when the latter is in its uppermost position defining a throat through which scrap to be sheared advances, hydraulic ram means mounted at the upper end of each of said column members for pivotal movement transversely of said throat and connected to the adjacent side of said crosshead for relative pivotal movement transversely of said throat, whereby by selective differential operation of said ram means, said movable cutting blade may be oppositely inclined for shearing cooperation with said fixed cutting blade.

3. The structure defined in claim 1 in which the column members define second opposed upright channel-like side guideways on that side of the first guideways remote from the fixed cutting blade, clamp-like hold-down means mounted in said second guideways for vertical reciprocating and rocking movements, and second hydraulic ram means mounted at the upper end of each of said column means for pivotal movement transversely of the throat and connected to the adjacent side of said hold-down means for relative pivotal movement transversely of said throat, whereby said hold-down means can conform to the transverse configuration of the upper surface of scrap to be sheared.

4. The structure defined in claim 3 including third hydraulic ram means mounted adjacent the lower end of each of said second guideways for extension transversely inwardly of the bed, and a head on each of the said third ram means for laterally engaging scrap on said bed.

5. The structure defined in claim 1 including pump means of predetermined maximum pressure for supplying pressure fluid to the ram means, check valves in the supply lines for the fluid for preventing back flow therein to said pump means, and pressure relief valves in the supply lines to the upper ends of said ram means for relieving pressure therein over a predetermined pressure greater than said pump maximum pressure, whereby if shearing resistance is encountered at a location along the length of the movable cutting blade sufficient to stall one of said ram means, the other of said ram means will exert a shearing force at said location greater than the force developable thereat when the crosshead is being moved downwardly by both of said ram means.

7. A method of shearing scrap metal with a scrap metal shear which includes a generally horizontal bed having at one end thereof a fixed cutting blade across which scrap to be sheared advances, upright side column members secured to said bed, one at each side thereof, defining opposed channel-like upright side guideways, a crosshead mounted for vertical reciprocating and rocking movements in said guideways and having a movable cutting blade cooperative with said fixed cutting blade, said bed, column members, and crosshead when the latter is in its uppermost position defining a throat through which scrap to be sheared advances, hydraulic ram means mounted at the upper end of ach of said column members for pivotal movement transversely of said throat and connected to the adjacent side of said crosshead for relative pivotal movement transversely of said throat, whereby by selective differential operation of said ram means, said movable cutting blade may be oppositely inclined for shearing cooperation with said fixed cutting blade, starting from a position wherein the crosshead is in a horizontal position above scrap to be sheared, the steps comprising: a. advancing one of the ram means downwardly while maintaining the other stationary until the movable cutting blade is inclined at a preselected angle to the fixed cutting blade, and b. advancing both ram means downwardly in unison to shear scrap.

8. The method defined in claim 7 including the further sequential steps of continuing to advance both rams downwardly in unison to shear scrap until approximately one-half of the length of the movable cutting blade is below the fixed cutting blade, and maintaining the one ram means stationary while advancing the otHer downwardly to shear scrap until substantially the entire movable cutting blade is below the fixed cutting blade.

10. The method defined in claim 7 in which the preselected angle is of the order of 10*.

11. A method of shearing scrap metal with a scrap metal shear which includes a generally horizontal bed having at one end thereof a fixed cutting blade across which scrap to be sheared advances, upright side column members secured to said bed, one at each side thereof, defining opposed channel-like upright side guideways, a crosshead mounted for vertical reciprocating and rocking movements in said guideways and having a movable cutting blade cooperative with said fixed cutting blade, said bed, column members, and crosshead when the latter is in its uppermost position defining a throat through which scrap to be sheared advances, hydraulic ram means mounted at the upper end of each of said column members for pivotal movement transversely of said throat and connected to the adjacent side of said crosshead for relative pivotal movement transversely of said throat, whereby by selective differential operation of said ram means, said movable cutting blade may be oppositely inclined for shearing cooperation with said fixed cutting blade, starting from a position wherein the crosshead is in a horizontal position above scrap to be sheared, the steps comprising: a. advancing one of the ram means downwardly while maintaining the other stationary until the movable cutting blade is inclined at a preselected angle to the fixed cutting blade, b. advancing both ram means downwardly in unison to shear scrap until blocking shearing resistance is encountered by both ram means, c. retracting either or both ram means to cause the movable cutting blade to be inclined at an opposite preselected angle to the fixed cutting blade, and d. advancing both ram means downwardly in unison to shear scrap.

12. A method of shearing scrap metal with a scrap metal shear which includes a generally horizontal bed having at one end thereof a fixed cutting blade across which scrap to be sheared advances, upright side column members secured to said bed, one at each side thereof, defining opposed channel-like upright side guideways, a crosshead mounted for vertical reciprocating and rocking movements in said guideways and having a movable cutting blade cooperative with said fixed cutting blade, said bed, column members, and crosshead when the latter is in its uppermost position defining a throat through which scrap to be sheared advances, hydraulic ram means mounted at the upper end of each of said column members for pivotal movement transversely of said throat and connected to the adjacent side of said crosshead for relative pivotal movement transversely of said throat, whereby by selective differential operation of said ram means, said movable cutting blade may be oppositely inclined for shearing cooperation with said fixed cutting blade, starting from a position wherin the crosshead is in a horizontal position above scrap to be sheared, the steps comprising: a. advancing one of the ram means downwardly while maintaining the other stationary until the movable cutting blade is inclined at a preselected angle to the fixed cutting blade, b. advancing both ram means downwardly in unison until blocking shearing resistance is encountered by one of said ram means, and c. continuing to advance the other of said ram means downwardly to shear scrap.

13. A method of shearing scrap metal with a scrap metal shear which includes a generally horizontal bed having at one end thereof a fixed cutting blade across which scrap to be sheared advances, upright side column members secured to said bed, one at each side thereof, defining opposed channel-like upright side guideWays, a crosshead mounted for vertical reciprocating and rocking movements in said guideways and having a movable cutting blade cooperative with said fixed cutting blade, said bed, column members, and crosshead when the latter is in its uppermost position defining a throat through which scrap to be sheared advances, hydraulic ram means mounted at the upper end of each of said column members for pivotal movement transversely of said throat and connected to the adjacent side of said crosshead for relative pivotal movement transversely of said throat, whereby by selective differential operation of said ram means, said movable cutting blade may be oppositely inclined for shearing cooperation with said fixed cutting blade, starting from a position wherein the crosshead is in a horizontal position above scrap to be sheared, the steps comprising: a. advancing one of the ram means downwardly while maintaining the other stationary until the movable cutting blade is inclined at a preselected angle to the fixed cutting blade, b. advancing both ram means downwardly in unison until blocking shearing resistance is encountered by one of said ram means, c. continuing to advance the other of said ram means downwardly to shear scrap until blocking shearing resistance is encountered by the other ram means, d. retracting both ram means to the starting position, e. advancing the other of the ram means downwardly while maintaining the one stationary until the movable cutting blade is inclined at an opposite preselected angle to the fixed cutting blade, and f. advancing both ram means downwardly in unison to shear scrap.