Abstract:
A guillotine type stud cutter with a frame with side rails and a guillotine blade slidably mounted between the rails has spaced, fixed, parallel, stationary die plates secured transversely between the side rails. Immediately inboard of the stationary die plates, sets of spaced parallel shear plates are slideably mounted for movement transversely of the side rails and toward and away from one another. The shear plates have opening defined by wall margins with sharp edges substantially perpendicular to an inside surface of the shear blades, to receive sheet metal studs of different sizes.

Description:
CROSS REFERENCE TO RELATED APPLICATIONS 
     STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH OR DEVELOPMENT 
     Not Applicable 
     BACKGROUND OF THE INVENTION 
     Guillotine type construction industry stud cutters are well known commercially. In the cutters now known, a pair of spaced die blades, with openings in them to accommodate different widths of studs have been fixedly mounted within a frame. A guillotine blade moving through the space separating the plates, sheers the stud. In the present application, “stud” is used generically to encompass not only studs used in the walls of buildings, but also floor joists, rafters, gutters, and the like trough-like shapes. 
     One of the problems with the machines known heretofore arises from the fact that although studs are supposed to come in a variety of standard sizes, the fact is that they vary in width from the standard. Thus, a 3½ inch wide stud may in fact be 3⅜ or 3⅝ inches wide. In order to accommodate these variations, the openings in the die blades have had to be made wider than any but the largest of the off-sizes for each of the standards; then when a relatively narrow stud is inserted, when the guillotine blade, which has a v-shaped center tooth, comes down, it tends to splay the sidewalls of the stud at the end at which it is cut, and if the largest of the off-sized stud of that standard is cut, the blade tends to bend down the inwardly extending flanges of the stud. Neither of these is desirable. In fact, with most commercial machines, the flanges are unsupported during the cutting, so that they tend to be bent down in any event. 
     One of the objects of this invention is to provide a machine in which the stud is supported against splaying and the flange is supported against being bent down, regardless of the variation, within limits, from the standard width. 
     Other objects will become apparent to those skilled in the art in light of the following description and accompanying drawings. 
     BRIEF SUMMARY OF THE INVENTION 
     In accordance with this invention, generally stated, in a guillotine blade type stud cutter, with side rails between which the blade moves in a direction lengthwise of the rails, spaced, fixed, parallel back-up or stationary die plates are secured transversely between the side rails. Immediately inboard of the stationary die plates, spaced parallel punch or shear plates, spaced closely to receive between them the blade, are mounted for sliding movement toward and away from one another transversely of the side rails, i.e., parallel to the pairs of stationary die plates. In this embodiment, the stationary die plates have openings in them to receive the walls and flanges of studs of all expected variations in width from the standard of various standard widths. The shear plates also have openings in them, and both the stationary die plates and the shear plates have lip openings to receive the flanges of the studs. Because the shear plates are movable transversely of the machine frame, a stud can be put into the opening, the plates moved until they engage the sidewalls of the stud and then backed off a very small amount, so that the next stud of the same lot can be slid into place without readjusting the spacing of the shear plates. If the side walls of the stud extend at an obtuse angle from a bottom wall, the “vertical” openings or slots can be angled complementarily. Both are embraced within the term “substantially vertical” as used to describe the side wall slots in the stationary die plates and shear plates. The flanges of the stud are supported on lip opening defining facing surfaces of the shear plates. The stud to be sheared is supported by the shear plates well within the elastic limits of the stud&#39;s side walls and flanges, so that no splaying of the side walls or permanent bending of the flanges is produced during the shearing process. Generally, all of the studs of a given lot have the same width. If they do not, it is an easy matter to readjust the position of the shear plates. 
     In the preferred embodiment, a support arm is provided, projecting perpendicularly from the machine frame, and centered with respect to the cutting blade. Studs with closed bottoms aligned along an upper surface of the support bar, can be slid into the slots of the stationary die and the shear plates. An indexing pin is movably mounted along the support bar and clamped in position, so that, when the pin, which is normally spring-biased to that position, is projecting above the surface of the bar, a stud can be pushed against it to position the stud for the exact length desired. The pin is actuated in response to the cutting movement of the blade to retract from its indexing position above the surface of the support bar, so that the stud can easily be withdrawn. 
    
    
     BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWINGS 
     FIG. 1 is a view in front elevation of one embodiment of machine of the present invention; 
     FIG. 2 is a somewhat enlarged view in front elevation of a stationary die plate and sliding shear plate assembly; 
     FIG. 3 is a fragmentary view in front elevation of the assembly shown in FIG. 2, with a front stationary die plate and blade partly broken away, showing shear plates in one position; 
     FIG. 4 is a view in front elevation of the assembly as shown in FIG. 3, showing the shear plates in a second position; 
     FIG. 5 is a sectional view taken along the line  5 — 5  of FIG. 2, with a fragmentary stud shown in phantom lines; 
     FIG. 6 is a sectional view taken along the line  6 — 6  of FIG. 2; 
     FIG. 7 is a sectional view taken along the line  7 — 7  of FIG.  1 . 
     FIG. 8 is a view in end elevation taken along the line  8 — 8  of FIG. 2; 
     FIG. 9 is a fragmentary view in side elevation of a support and indexing fixture connected to the machine of FIG. 1, showing an indexing finger in a stop position; 
     FIG. 10 is a fragmentary view in side elevation showing the indexing finger in retracted position; 
     FIG. 11 is a top plan view, taken along the line  11 — 11  of FIG. 1; 
     FIG. 12 is a fragmentary view in side elevation taken along the line  12 — 12  of FIG. 1; 
     FIG. 13 is a fragmentary bottom plan view of the indexing device of FIGS. 9 and 10, showing one embodiment of clamp for holding the index cylinder along the support; and 
     FIG. 14 is a fragmentary view in front elevation of another embodiment of stationary die plate. 
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT 
     Referring now to the drawing for one illustrative embodiment of this invention, reference numeral  1  indicates the stud shearing mechanism of an assembled machine. The machine itself includes a cabinet, not here shown, which supports the mechanism  1 , and contains a hydraulic pump, among other things, but this is conventional in such machines. The mechanism  1  has a supporting frame  2  with side rails  3  and a base bar  4 . The side rails  3  are made up of two heavy, spaced, parallel plates  5 , as is the base bar  4 . A spacer plate extends across the base bar, between the two plates making up the base bar. Intermediate spacers, in the embodiment shown, in the form of spools, and top spacers  9 , in the form of spools like the intermediate spools, hold the side rails parallel to one another. 
     A blade frame  14  is constructed to slide between the side rails  3 . The blade frame has a top cross piece or header  16 , made up of spaced plates spaced to receive a blade  30  and dimensioned to extend slidably between the bars making up the side rails. Bolts through the header plates secure the blade to the header. The blade frame  14  has a bottom cross piece  19  with a hole vertically aligned with a hole in the base bar. Straps  22  are attached to and extend between the bottom cross piece  19  and the header  16 . Outer edges  23  of the straps ride against an inboard edge of the side rails  3 , serving to hold the blade  30  centered. The blade  30  has a web  31  secured at its upper end to the top cross piece  16 , and at its lower edge, has teeth  32 , made up of a center tooth  33  with a point  34 , and edges  35  forming a shallow V, and side teeth  36  with edges  37 , meeting the edges  35  of the center teeth in a slightly obtuse angle. 
     A pair of heavy stationary die plates  40  extend transversely of the side rails  3  above the bottom cross piece  19 . The plates  40  are elongatedly rectangular, and are separated by upper spacer block guides  41  and lower spacer block guides  42  which, along a vertical inboard surface, also serve as guides to the edges of the blade web. The stationary die plates are separated just far enough slidably to admit the blade  30 , with, for example, 0.002″ clearance, as shown particularly in FIG.  6 . On their inboard broad surfaces, the stationary die plates have channels  43 , opening at each outer end of the stationary die plates. Sliding shear plate assemblies  47  are mounted in the channels  43 . Stud-admitting openings  44  in the two plates making up the pair of stationary die plates are exactly aligned front to back. The openings  44  are sharply defined. Each opening has vertical components defining an opening wide enough to admit studs that vary from the standard width within the expected range, a lip  45  to receive a flange, and, to accommodate a common stud with shorter end walls, one pair of openings is shown with a supplemental lip  46 . The individual vertical slots in the stationary die plates end above a continuous lower horizontal slot  50 . The lower edge of the slot  50  on each of the die plates  40  is defined by an upwardly facing surface that serves to support the stud during the shearing of the stud. Sharp inner edges of the upwardly facing surfaces of the stationary die plates serve as the die which, as the blade  30  passes by, shears the web constituting the bottom of the stud. 
     The shear plates assemblies  47  are made up of two, spaced, left shear plates  48  and two, spaced, right shear plates  49 , the left and right shear plates being mirror images of one another. Both of the shear plates  48  and  49  are elongatedly rectangular, and are seated slidably in the channels  43 , which are deep enough to permit the shear plates  48  and  49  to fit with facing surfaces flush with the inboard facing faces of the stationary die plates  40 . The two plates making up each of shear plates  48  and  49  are therefore spaced to receive the blade  30  closely but slidably. The shear plates  48  and  49  have in them paired, mirror-image openings  53  defined by sharp, abrupt edges, vertical edges  54  and horizontal lips  55 . The openings  53  have the same contour as openings  44  in the stationary die plates  40 , including a supplemental lip  58  corresponding to the lip  46  in the stationary die plates, but the plates  48  and  49  have no cross piece defining a slot corresponding to the slot  50  in the stationary die plates, the shear plates moving toward and away from one another in use. The openings  53  are open at their lower ends. 
     In this embodiment, each of the sliding shear plates  48  and  49  is secured to a shear plate end cap  65  at its outer end. The end cap  65  includes a block  66 , the height of the shear plates, and a tenon-spacer  67  integral with block  66  and extending between the plates of each of the shear plates a distance sufficient to permit the shear plates to be securely connected to it. The shear plates are made of hardened steel, for example, D-2 steel with a Rockwell hardness of 58 to 60. The end cap  65  can be made of mild steel. 
     An operating mechanism  75  includes a screw rod  76  with right hand threads. 85  at a handle end and left hand threads  86  at an opposite, bearing end. Screw receiving blocks  84  are fastened to an outboard surface of the end cap block  66 . The screw receiving blocks  84  are wider than the end cap blocks  66 , and extend flush with one long side of the end cap blocks and along and beyond the opposite side of the end cap blocks  66 . The screw receiving blocks  84  have a flat part  88  bolted to the end cap block  66  and a part  89  projecting above the block  66 . An internally threaded hole in each of the projecting parts  89  to receive the threaded parts of the screw rod  76  is offset from the end cap block  66  far enough to permit the rod  76  to clear the blade  30 , the rod  76  extending between the blade and one of the straps  22 . The threaded holes in the projecting part are threaded appropriately for the threads of the rod  76 . 
     A screw end-receiving, L shaped bracket  95 , with a long leg  96  fixed to the frame and a short leg  97  at right angles to the long leg, positioned to receive the outer end of the screw rod, has a bearing passage to receive a bearing surface of the screw rod at its free, bearing, end, which also has, at its outermost end, a nut-receiving thread on which a nut  98  is mounted. 
     A crank handle  79  is connected to the screw rod at the end of the rod opposite the bearing end. Because the threads at opposite ends of the screw rod are oppositely handed, when the crank handle  79  is turned, the shear plates  48  and  49  move toward or away from one another. 
     A hydraulic cylinder  90  is connected at its lower end to the base bar  4 . A piston  91 , carried by the hydraulic cylinder  90 , is connected by a clevis  92 , at its upper end to the bottom cross piece  19  of the blade frame  14 . The hydraulic cylinder  90  is connected to a source of hydraulic fluid pressure, not here shown. When hydraulic fluid is admitted to an upper chamber of the cylinder  90 , the piston is forced down, pulling the blade frame, hence pulling the blade through the space betwen the shear plates  48  and  49 , thence between the stationary die plates below the slot  50 , shearing and stud  10  extending between them. When hydraulic fluid is admitted to a lower chamber of the cylinder  90 , the piston is moved back up to its ready position. A smaller fluid cylinder  101 , acting as a pump, is connected to the base bar  4 , and has a piston  107  connected at its upper end to the bottom cross piece  19 . The cyliner  101  is connected by a fluid line  106  to a cylinder  102  of an indexing pin assembly  100 . The cylinder  102  actuates an indexing pin  103 . The indexing pin assembly is mounted on a long support bar  104 , to be selectively positioned along the length of the long support bar  104 . In FIG. 13, a C-clamp  108  is shown as connected to the cylinder  102  and embracing the bottom and two sides of the support bar, to permit the cylinder to be held at any desired position along the support bar, although any suitable clamping device can be used. The support bar  104  is connected at one end to the frame of the machine. The top surface of the support bar is level with the lower horizontal portion  50  of the openings in the stationary die plates, so that a stud placed with its flat bottom wall on the support bar, can be slid directly into the appropriate slots in the stationary die plates with its bottom resting on the top of the wall defining the bottom of the horizontal portion  50 , or, if the stud is being fed from the opposite side, can be supported by the support bar as it emerges from the slots. The distance from the end of the stud to the blade is determined by the impingement of the end of the stud against the indexing pin, which is normally biased to project above the upper surface of the support bar. When the blade is pulled down by the hydraulic cylinder  90  and its piston, to shear the stud, the piston  107  of the cylinder  101  moves down in the cylinder, and its action pulls the indexing pin down out of the way of the stud, so that the stud can be slid along the support bar and removed to make way for the next stud. 
     As has been explained heretofore, the shear plates  48  and  49  are moved, by turning the crank handle  79 , either toward or away from one another, to accommodate the width of the stud to be sheared, at which point the flanges of the stud are supported by the ledges  45  and the side walls of the stud are constrained by the side walls of the vertical slots of the shear plates. 
     Referring now to FIG. 14 for another embodiment of stationary die plates, instead of having individual openings cut in the plates, the area occupied by individual openings in the stationary plates of the first embodiment is all cut away, leaving a central island  141  to provide lateral support for the shear plates  48  and  49 , and leaving a supporting area  140 , a central section of which defines the opining  50 , as in the embodiment first described and, outboard of the central section, area, lower margins of the channels  43 , also as in the embodiment first described. This configuration is easier to fabricate, and provides all the support necessary for the shear plates. 
     Numerous variations in the construction and operation of the machine of this invention, within the scope of the appended claims, will occur to those skilled in the art in the light of the foregoing disclosure. Merely by way of example, the threads on the screw rod can be reversed, with the threads at the handle end being left hand, and the threads at the bearing end, right hand. The configurations of the slots in the stationary die and die plates can be varied to suit the configurations of the studs to be sheared, as for example gutters, or studs with rolled edges, or H beams (in which case, the lower slot  50  can be modified as well). The height of the slots and position or configuration of the lips  45  can also be varied, to suit the height of the side walls of different studs and the configuration or width of the inturned flanges. The numbers of slots can also be varied, to accommodate different studs. The mechanism by which the die plates are moved can be different from the screw rod arrangement shown, as, for example, by the use of hydraulic cylinders and pistons or by electrically driven worm drives. The channels in the stationary die plates and the upper and lower edges of the die plates can be complementarily chamfered to dovetail, to ensure that the die plates do not move in a direction front to back with respect to the stationary die plates. The block  84  need not be offset through its entire length; it can be L shaped, carrying an ear at its upper end that has a threaded hole in it offset from the block  66  to receive the screw rod at each end. Although the arrangement described is by far preferred, stationary die plates themselves can be divided, the continuous slot  50  made discontinuous, and the stationary die plates constructed to move toward and away from one another, supported by L shaped cross members between the side rails, for example. An upper surface of a lower L shaped cross member can serve the function of the upwardly directed surface  51  of the slot  50 . When the stationary die plates are made movable, the stationary die plates become shear plates. The indexing pin can be actuated electrically, as by using a switch, thrown when the blade moves down, to energize a solenoid to pull the pin down. These variations are merely illustrative.