Magazine feed of connector plate stock
United States Patent [1 1 Jureit et al..  
 [ 51 Apr. 15, 1975 MAGAZINE FEED OF CONNECTOR PLATE STOCK [75] Inventors: John Calvin Jureit, Coral Gables;  
 Ben Kushner, Miami; Roy Leutwyler, Miami; Adolfo Castillo, Miami, all of Fla.  
 [73] Assignee: Automated Building Components,  
 Inc., Miami, Fla.  
 [22] Filed: Dec. 27, 1973 [21] Appl. No.: 428,851  
 [52] US. Cl. 221/236; 221/268; 221/297;  
  221/251 [51] Int. Cl B65h 5/00 [58] Field of Search 221/236, 297, 268, 238,  
 Primary ExaminerAllen N. Knowles Attorney, Agent, or Firm-LeB1anc &amp; Shur [57] ABSTRACT One form of the magazine includes three superposed slides on each side of a chute for receiving discrete lengths of stacked connector plates of the type formed of sheet metal with teeth struck to project to one side thereof. The plates are stacked in pairs with the teeth of the respective plate in each pair projecting toward the other plate. The lowermost third slide and a surface spaced below the slides constitute first and second positions for feeding the plates into a machine. In use, the plates are stacked on the third slide with the first and second slides retracted. The first and second slides are extended to grip the stack with the second slide underlying the next to the last plate in the stack. The first slide is retracted and the first plate drops to the first feed position. The first slide is extended and the second slide is retracted to drop the second plate onto the first slide and into the second feed position with the stack being held in spaced relation above the plates in the feed positions by the extended third slide. A pusher element slides the pair of plates longitudinally from the feed positions into the machine. In another form, a pair of screws or augers dropped pairs of stacked plates in sequence onto slides which respectively locate the plates in first and second feed positions.  
 17 Claims, 17 Drawing Figures SHEET 1 [IF 6 HUI lulu  
 TQITEiT IriFRTSiEYS 3 71 0 HUM Xvm 227 PATENTEUAPR 1 5197s FI&#39;GYD FIG .8  
 MAGAZINE FEED OF CONNECTOR PLATE STOCK The present invention relates to a material handling apparatus for feeding discrete lengths of stacked connector plates to a machine for cutting and pressing op erations. the plates being of the type having a plurality of teeth struck to project to one side thereof. Particularly, the present invention relates to magazine feeding of connector plates to a machine which cuts the connector plate stock to discrete lengths thereof and simultaneously embeds the plates cut into opposite sides of a wooden frame. The present invention also relates to methods for accomplishing the foregoing.  
  In prior copending U.S. patent application Ser. No. 317,095 filed Dec. 20, 1972 now abandoned of common assignee herewith, there is disclosed apparatus and methods for forming wooden frames and particularly apparatus and methods for cutting connector plates of the type having prepunched integrally extend ing teeth from coiled strips thereof and substantially simultaneously pressing the discrete plates thus formed into the opposite sides of the joints of a wooden frame. In that apparatus, connector plate stock is coiled on large reels and fed from the coils directly to the machine which performs the cutting and pressing operations. The apparatus and methods disclosed in that application and particularly the feeding of coil connector plate stock into the machine has proven an eminently satisfactory method for efficient formation of wooden frames. The present invention is concerned with the feeding of a machine of the type disclosed in that prior application Ser. No. 317,095 with discrete lengths of stacked connector plate stock rather than feeding such machine from coiled connector plate stock. That is, the present invention is concerned with the provision of a magazine of the type wherein discrete lengths of connector plate stock are stacked in face-to-face relation one to the other with pairs of such connector plate stock being sequentially segregated from the stack thereof and fed to the machine. Since an understanding of the disclosure of the machine as set forth in U.S. patent application Ser. No. 317,095 filed Dec. 20, 1972, now abandoned is necessary for a complete understanding of the present invention, the disclosure of U.S. patent application Ser. No. 317,095 filed Dec. 20, 1972, now abandoned is incorporated herein by reference thereto as though fully set forth herein.  
  Briefly, in prior application Ser. No. 317,095, now abandoned, there is disclosed a machine including upper and lower press head assemblies carried on each of the opposite sides of a conveyor. Each press head assembly includes a platen, upper and lower platens being movable toward and away from one another and located on opposite sides of frame members disposed on the conveyor. Each platen carries a cutting blade which cooperates with a fixed cutting blade to cut a selected length of connector plate from the coiled connector plate stock fed to each such press head assembly. The feed assembly as disclosed in that application for supplying the connector plate stock to the machine includes apparatus for mounting a pair of coils of the connector plate stock on opposite sides of the conveyor and apparatus for unwinding the coil and feeding the leading portions of the coiled stock to the respective press head assemblies. With the chords and webs of a frame to be fabricated disposed on the conveyor and LII the joints thereof between the upper and lower press head assemblies. the upper and lower platens move toward one another cutting predetermined lengths of connector plates from the coiled connector stock and substantially simultaneously embedding the cut connector plates into the opposite sides of the joints of the wooden frame. Upon retraction of the platens and movement of the partially completed frame to another position locating a subsequent joint between the press platens, the platens again cut connector plates from the coiled connector stock and embed the plates thus cut into the opposite sides of the joint. This cycle is repeated until fabrication is complete.  
  It will be appreciated from a review of prior application Ser.. No. 317,095 now abandoned. that the coiled connector plate stock solves significant material handling problems encountered with respect to connector plates of this type; that is. connector plates of the type having teeth struck integrally therefrom and projecting to one side. While the coiled stock feed shown in that application is eminently satisfactory, an alternative type of feed mechanism for feeding connector plate stock into the machine disclosed in that application has been developed In this alternative form, the connector plate stock is provided in linearly extending discrete lengths thereof stacked one against the other. That is, discrete lengths of longitudinally extending connector plate stock, each length being significantly greater than the length of the connector plates to be cut therefrom and embedded into the wooden frame, preferably a whole multiple thereof, are stacked one against the other with adjacent plates having teeth projecting in opposite directions toward one another. The plates are preferably stacked vertically although horizontal stacking of plates and feeding of the stack in a horizontal direction may also be accomplished. The apparatus in one form hereof sequentially segregates the pairs of connector plates which have their teeth projecting toward one another from the stack and locates the plates of each successive pair thereof in position for feeding to the machine described above and in prior patent application Ser. No. 317,095 now abandoned.  
  More particularly, and in this one form of the present invention, the magazine feeding apparatus hereof includes a pair of vertically spaced horizontal surfaces which define positions for feeding pairs of connector plate stock into the machine. The upper surface is defined by a pair of slides on opposite sides of upstanding guides confining a vertically disposed stack of connector stock, these slides being movable into and out of engagement with the stacked connector stock at that elevation. Superposed above this first pair of slides are second and third pairs of slides each mounted for movement into and out of engagement with the stacked connector stock disposed between the guides. These three pairs of slides on opposite sides of the stacked connector plate stock are operated sequentially to locate a first length of connector plate stock with its teeth facing upwardly on the bottom feeding surface, and a second length of connector plate stock on the first pair of slides with its teeth facing downwardly, the stacked connector plate stock being spaced above the first and second lengths of connector plate stock when in the feed positions. A push rod is then actuated to advance the first and second lengths of stock into the machine. Upon retraction of the rod, another pair of the connector plate stock is disposed in the first and second feed positions for subsequent feeding thereof to the machine. It will be appreciated that sets of such slides are located at longitudinally spaced positions for supporting and feeding lengths of such connector plate stock to the machine. the number of the sets of slides being dependent upon the length of the connector plate stock and the spacing required between the sets of slides to support the stock without bowing or otherwise interfering with the feeding operation.  
  In another form hereof, the stacked discrete lengths of connector plate stock are carried between screws or augers which continuously rotate to lower pairs of the stacked plate stock into feeding positions. In this form, a first pair of connector plate stock in back-to-back relation, are disposed on a first slide. The slide is movable laterally to transfer the lowermost length of plate having its teeth projecting in a downward direction into a first feed position. Upon retraction, the second length of plate drops past the first slide onto a surface in lateral opposition to another whereupon the lower length of plate with its teeth projecting upwardly is disposed in a second feeding position in vertical registry below the first length of plate. The plates are thereafter displaced longitudinally into the machine. Upon their displacement, the augers have rotated sufficiently to deposit another pair of connector plate stock in back-tback relation on the first slide whereupon the feeding cycle is repeated.  
  Accordingly, it is a primary object of the present invention to provide a novel and improved magazine feed for connector plate stock and methods therefor.  
  It is another object of the present invention to provide a novel and improved magazine feed for feeding connector plate stock into a machine of the type which cuts the stock to discrete lengths to form connector plates and embed the plates into the joints between adjacent wooden members.  
  It is still another object of the present invention to provide a novel and improved magazine feed for connector plate stock wherein the feeder sequentially segregates pairs of connector plate stock from a stack thereof for disposition into machine feeding positions.  
  It is still another object of the present invention to provide a novel and improved magazine feed for connector plate stock of the type having teeth struck to one side wherein lengths of connector plate stock are readily and easily separated one from the other and from the stack for disposition in a machine feeding position.  
  These and further objects and advantages of the present invention will become more apparent upon reference to the following specification, claims and appended drawings wherein:  
  FIG. I is a vertical cross-sectional view of a portion of a machine for fabricating wooden frames and a magazine constructed in accordance with the present invention for feeding discrete lengths of connector plate stock to the machine, portions of the magazine being broken away for ease of illustration;  
  FIG. 2 is an end elevational view of the magazine feed illustrated in FIG. 1 with portions thereof broken away and in cross section for ease of illustration;  
 FIG. 3 is a top plan view thereof;  
  FIGS. 4A 4F are fragmentary endwise crosssectional views of the magazine feed hereof illustrating the operational sequence for locating a pair of lengths of connector plate stock in position for feeding to the machine illustrated in FIG. 1;  
  FIG. 5 is a schematic view illustrating a pneumatic circuit for operating the mechanism of FIGS. 1-4;  
  FIG. 6 is an electrical schematic view ofa control circuit for sequencing the various parts of the magazine of the present invention;  
  FIGS. 7A 7E are end cross-sectional views with parts broken away and in cross section illustrating the operational sequence for feeding a pair of lengths of connector plate stock to a fabricating machine in accordance with another form of the present invention; and  
 FIG. 8 is a fragmentary top plan view thereof.  
  Referring now to the drawings and particularly to FIG. 1, there is illustrated in the left-hand portion thereof part of a wooden frame fabricating machine generally designated 10. This machine is disclosed in detail in prior application Ser. No. 317,095 now abandoned. For present purposes it is sufficient to note that the machine includes a pair of upper and lower mounting blocks 12 and 14 respectively, mounted between generally C-shaped plates, one of which is illustrated at 16. A pair of plates 18 and 20 are carried on the lower and upper sides of blocks 12 and 14 respectively, and have slots therethrough to define respective upper and lower connector plate stock passages 22 and 24. The lower ends of plates 18 and 20 carry fixed cutting blades 26 and 28, each being provided with a plurality of transversely spaced tines defining grooves therebetween for receiving the teeth of the stock. The upper and lower portions of blocks 12 and 14 carry upper and lower press cylinders 30 and 32, respectively, the lower ends of which carry respective press platens 34 and 36. The rear edges of platens 34 and 36 are provided with cutting blades 38 and 40, respectively, for cooperation with respective fixed cutting blades 26 and 28 whereby connector plate stock issuing through passages 22 and 24 between platens 34 and 36 may be cut upon movement of the platens toward one another to form connector plates P of discrete selected lengths. In accordance with the disclosure of the prior application, it  
 will be appreciated that chord and web members of a frame undergoing fabrication are disposed between the movable platens 34 and 36 whereby the teeth of the connector plates P are embedded into opposite sides thereof. The teeth of the upper plate P are, of course, directed downwardly while the teeth of the lower plate are directed upwardly, i.e., the teeth are in opposition one to the other for proper positioning on oppositesides of the frame undergoing fabrication.  
  A stock feed and clamp assembly is generally designated 42 and includes a slide block 44 mounted on a pair of guide rods 46 for reciprocating movement in a longitudinal direction. Block 44 carries upper and lower jaws 48 and 50, respectively, each of which is grooved in a longitudinal direction to form transversely spaced tines. Mounted on opposite sides of slide 42 are upper and lower cylinders 52 and 54, respectively, the pistons of which carry grippers 56 and 58, respectively. It will be appreciated that upon extension of the pistons the grippers move toward the opposite jaws to clamp the connector plate stock between the tines of the jaws and the grippers. A cylinder 60 is secured to a fixed part of the machine and its piston rod 61 is secured to block 44 whereby extension and retraction of piston 61 advances and retracts slide block 44. When the slide block is retracted; that is, when moved to the right from the position illustrated in FIG. I, cylinders 52 and 54 are actuated by means not shown but disclosed in prior application Ser. No. 317.095. now abandoned to grip the connector stock plate S. Upon actuation of cylinder 60 the stock is advanced into position below and above the upper and lower platens 34 and 36 respectively. Upon release of the stock by retracting grippers 56 and 58, piston 60 retracts slide block 44 to again engage the stock and advance the same to the cutting and pressing positions. This cycle is repeated for each cutting and pressing operation. The stock S moves along upper and lower stock guide tables 62 and 64 respectively. Cylinders 66 and 68 indicated by the dashed lines in FIG. I carry pins 70 and 72 respectively, which are inserted between the teeth of the stock to align the stock such that the cutting blades are aligned between the transverse rows of teeth. In this manner, the stock is cut at locations other than through the teeth. The pins are, of course, retractable by the pistons when the stock S is being advanced into the cutting and pressing position similarly as set forth in the prior application.  
  One form of the magazine feed hereof is generally illustrated at 80 and comprises a plurality of upstanding guide rods 82 arranged in a pair of transversely spaced longitudinally extending rows to define a chute therebetween for receiving stacked connector plate stock. That is, lengths of connector plate stock, preferably whole multiples of the discrete lengths required for the connector plates used in fabricating the wooden frame, are disposed in stacked relation within the chute defined by the upstanding guides 82. Preferably, the lengths of connector plate stock are stacked such that adjacent plates have their teeth extending in opposite directions one from the other. In a preferred form hereof, pairs of plates with the teeth thereof in opposition one to the other are sequentially fed from the stacked lengths of connector plate stock into feeding position; that is, with an upper length of connector plate stock having downwardly projecting teeth disposed in horizontal alignment with the upper stock guide table 62 and a lower length of connector plate stock having upwardly projecting teeth disposed in horizontal alignment with the lower stock guide table 64. A push rod 84 is disposed in a retracted position at the end of the chute removed from machine and is extendable through the chute at the level of the connector plate stock in the feeding positions to displace the lengths of stock therefrom onto the stock guide tables 62 and 64 and into position for clamping by the stock advance assembly 42.  
  To sequentially segregate the lowermost pairs of lengths of connector plate stock from the stack thereof and one from the other for location in the positions for feeding machine 10, a plurality of sets of slides are disposed at spaced longitudinal positions along the magazine, each slide set being generally indicated 86. Thus, any length of connector plate stock can be provided the magazine with the addition or deletion of one or more of the sets of slides 86.  
  Turning now to FIGS. 2 and 3, there is illustrated a set of slides 86 mounted on a bottom plate 88, the upper surface of which defines a first feeding position in generally horizontal alignment with the lower stock table 64. The guides 82 upstand from lower plate 88. Three slides are mounted on each of the opposite sides of the chute between a pair of upstanding supports 90.  
 Particularly. a first pair of lower slides 92 are mounted on a fixed lower block 94. A second pair of slides 96 are mounted in horizontal opposition one to the other directly on top of the first pair of slides 92. A third pair of slides 98 are mounted in horizontal opposition one to the other across the chute directly on top of the second pair of slides 96. The respective opposed slides 92, 96 and 98 are mounted for relative sliding movement one to the other and for extension and retraction respectively toward and away from the chute. The slides are thus selectively spaced from or engageable with the connector plate stock stacked between guides 82.  
  The opposed edges 100 of slides 96 ae inclined along their upper surfaces whereby such edges can are engaged below the connector plate stock located at that elevation. The tips 102 of the third or upper slides 98 are also inclined upwardly for the same purpose, such tips comprising a pair of projections 104 at opposite sides of each slide 98 as illustrated in FIG. 3. Between projections 104 there are provided flexible resilient grippers 106 preferably formed of a rubberlike material for purposes which will become clear from the ensuing description. Pins 104, 106 and 108 are upstanding from the outer upper surface of each of the slides 92, 96 and 98, respectively, for connection with the piston rods of actuating pneumatic cylinders therefor. That is, each slide is mounted for sliding movement toward and away from the chute under the control of an air cylinder. For example, and as illustrated in FIG. 5, a pair of air cylinders 110 have their piston rods connected to the slides 92. Similarly, air cylinders 112 and 114 have their piston rods connected to the slides 96 and 96, respectively, where the slides are reciprocable in response to extension and retraction of the pistons of the cylinders. The sequence of operation of the slides whereby the lowermost pair of lengths of connector plate stock are segregated from the superposed stack and from one another for location in the feeding positions will now be described with respect to FIGS. 4A 4F. As illustrated in FIG. 4A and at the start of the feeding operation, lengths of connector plate stock are disposed in adjacent pairs thereof with the teeth of the respective lengths of each pair extending toward one another. The stack of connector plate stock is supported by the normally extended lower slides 92. Also, slides 92 support the stack with the lowermost length of plate Pl having its teeth projecting upwardly. To locate the lower pair of plates P1 and P2 in feeding positions, slides 96 and 98 are moved inwardly as illustrated in FIG. 4B. Inward movement of intermediate slide 96 causes tapered edges 100 to engage the underside of plate P2 whereupon the connector plate stock above plate P1 is supported by slides 96. Slides 98 engage surface 106 against the upwardly projecting teeth of the plate Pl, the first plate of the next pair of plates to be disposed in feeding position. In FIG. 4C, the lower slides 92 are then retracted whereupon lower plate Pl drops onto feed surface 88, the superposed stack being supported by intermediate slides 96. Lower slides 92 are then returned to the position illustrated in FIG. 4D whereupon intermediate slides 96 are retracted. Retraction of slides 96 permits plate P2 to drop downwardly onto slides 92, the superposed stack being supported by the engagement of surface 106 against the teeth of plate Pl. Plates P1 and p2 are thus disposed in feed positions and plunger 84 is advanced to displace plates P2 and P1 onto guide surfaces 62 and 64 for delivery to machine 10. Upon retraction of plunger 84, slides 98 retract. The stack thus steps downwardly to rest on lower slides 92 as illustrated in FIG. 4A. The cycle is then repeated upon command.  
  Referring now to FIG. 5, there is illustrated a pneumatic circuit for operating the cylinders coupled to the various slides. As illustrated, the piston rods of the cylinders 110, 112 and 114 are respectively connected to slides 92, 96 and 98. Each pair of cylinders for the corresponding slides are under the control of a four-way, two-position spring-returned solenoid actuated valve. For example. valve 116 is positioned to normally permit air under pressure via conduits 118 and 120 into cylinders 110 whereby the piston rods and slides 92 carried thereby remain in a normally extended position as illustrated. When valve 116 is shifted to its second position. air under pressure is provided cylinder 110 through valve 116 via conduits 118 and 121 to retract slides 92. Valve 122 is associated with the cylinders 112 for slides 96 while valve 124 is associated with the cylinders 114 for slides 98. Particularly, air under pressure is provided cylinder 112 through valve 122 via conduits 125 and 127 to normally maintain slides 96 retracted. When valve 122 is shifted to its second position, air under pressure is provided cylinders 112 through valve 122 via conduits 125 and 219 to thereby retract slides 96. Valve 124 similarly provides air under pressure to cylinder 114 via conduits 131 and 133 to normally maintain slides 98 retracted while when shifted supplies air to cylinder 114 via conduits 131 and 135 to extend slides 98. Each of valves 116, 122 and 124 is under the control of solenoid S126, S128 and S130, respectively. A spring-return four-way twoposition solenoid actuated valve 134 is interposed between a source of air under pressure and plunger cylinder 136. It will be appreciated from FIG. that air is supplied via conduits 138 and 140 to maintain plunger 142 in a normally retracted position and that shifting valve 134 to the left by actuating solenoid 138 supplies air to cylinder 136 via conduits 138 and 144 to extend plunger 142.  
  Turning now to FIG. 6, there is illustrated an electrical circuit diagram for operating the solenoids S126, S128, S130 and S138 in the appropriate sequence to extend and retract the slides and push rod 142. The circuit is illustrated in a detached contact mode wherein the various relays represented by circles, open and close associated contacts in a manner to be described, normally opened and closed contacts being denoted by the pairs of parallel lines and the slashed pairs of paral&#39; lel lines, respectively. The contacts have numeral suffixes corresponding to the numeral suffixes of their actuating relay.  
  Power is supplied by a source, not shown, across a line 150 in which there is provided start switch 152. Upon closing switch 152, the circuit is ready to initiate a feed cycle upon command. A feed command switch 154 is disposed in line 150. A relay A is connected in line 156 in series between switch 154 and a reference potential. Connected in series across which 154L and to line 156 are normally open contacts A3 and normally closed contacts G1. Connected in series via line 158 across line 150 and a reference potential are normally open contacts B1, solenoid S126, and normally closed contacts C1. Connected in series in line 160 across supply lines 150 is a normally open trip switch 162 and in parallel a Relay C, and time delay relays TDF and TDG. Also connected in series via line 164 across supply line 150 and the reference potential are normally open contacts A1 and solenoid S130. Connected in series in line 166 supply line 150 and the reference potential are normally open contacts A2, normally closed contacts F1, and solenoid S128. Connected in series in line 168 across supply line 150 and a reference potential is a relay TDB and normally closed contacts C3. Connected in series via line 170 across power supply line 150 and a reference potential and between switches 152 and 154 is normally open contact G2 and in parallel a relay H and solenoid S138. Connected in series in line 172 across supply line 150 and line 170 between contacts G2 and relay H and solenoid S138 is a normally closed feed complete switch 174 and normally open contacts H1. A line 176 connects between lines 172 and 164 and particularly connects in line 172 between supply line 150 and normally closed switch 174 and in line 164 between normally open contacts A1 and solenoid $130. A normally open feed cycle switch 178 is disposed in line 176.  
  In operation, switch 152 is closed to place the electrical circuit in a ready condition. To feed a pair of discrete lengths of connector plate stock to the machine command, switch 154 is momentarily closed thereby energizing relay A. Energization of relay A closes normally open contacts A3 which complete a holding circuit via line 156 for the circuit elements to the right of switch 154 as illustrated in FIG. 6. Energization of relay A also closes normally open contacts A1 thereby energizing solenoid S via lines and 164. Energization of solenoid S130 shifts valve 124 to the right as illustrated in FIG. 5 to supply air to cylinders 114 thereby extending slides 98 toward one another to grip plate P1 as illustrated in FIG. 4B. Energization of relay A also closes normally open contacts A2 to energize solenoid S128 via lines 150 and 166. Energization solenoid S128 shifts valve 122 to the right as illustrated in FIG. 5 to supply air to cylinders 112 thereby causing slides 96 to shift toward one another to support the stack as illustrated in FIG. 4B. Energization of relay A also causes energization of relay TDB after a short time delay. Energization of time delay relay TDB closes normally open contacts B1 whereby solenoid S126 is energized via lines 150 and 158. Energization of solenoid S126 causes valve 1 16 to shift to the right as illustrated in FIG. 5 whereupon airis supplied to cylinders 110 causing slides 96 to retract or move awayfrom one another as illustrated in FIG. 4C. As will be recalled,  
 movement of slides 92 away from one another permits.  
 the bottom plate P1 of the stack to drop onto feed surface 88. When plate Pl drops to surface 88, normally open trip switch 162 is closed whereupon relay C is energized via line 150 and 160. Energization of relay C opens normally closed contacts C1 to de-energize solenoid S126 whereupon valve 116 spring-returns to the position illustrated in FIG. 5 and air is supplied to cylinders 110 to extend slides 92 to the position illustrated in FIG. 4D. Energization of relay C also opens normally closed contacts C3 whereupon relay TDB is deenergized and contacts B1 are returned to their normally open position. After a short time delay, relay TDF is energized via lines 150 and and opens normally closed contacts-F1 to de-energize solenoid S128. De-energization of solenoid S128 permits valve 122 to spring-return to the left as illustrated in FIG. 5 whereupon air is supplied cylinders 112 to move slides 96 away from one another as illustrated in FIG. 4E. As will be recalled, movement of slides 96 as illustrated in FIG. 4E away from one another permits plate P2 to drop onto the extended slides 92 whereupon both plates P1 and P2 are in feed positions. Relay TDG is energized a short time after relay TDF is energized. Energization of relay TDG closes normally open contacts G2 to energize relay H and solenoid S138 via line 170. Energization of solenoid S138 shifts valve 134 to the right illustrated in FIG. 5 to supply air to cylinder 136 whereupon push rod 142 is extended to displace plates P1 and P2 from their respective positions on surface 88 and slides 92 as illustrated in FIG. 4E onto the guide tables 62 and 64 preliminarily to their disposition in machine 10. Energization of relay H closes normally open contacts H1 to provide a holding circuit for solenoid S138 via line 172 and normally closed switch 174. Energization of relay TDG also opens normally closed contact G1 whereupon the holding circuit through line 156 is broken and the circuit elements to the right of switch 154 in FIG. 6 with the exception of solenoid S130 are de-energized. When the I push rod 142 is moved to displace plates P1 and P2, switch 178 closes to maintain solenoid S130 energized via lines 172 and 176 whereupon slides 198 remain in the positions illustrated in FIGS. 4E and 4F while plates P1 and P2 are displaced toward machine 10. At the end of the push rod feed stroke, switch 174 opens and deenergizes relay H and solenoid S138. De-energization of solenoid S138 permits valve 138 to spring-return whereupon air is supplied cylinder 136 to return push rod 142 to its normally retracted position. Upon its return, switch 178 is opened thereby de-energizing solenoid S130 and permitting valve 124 to spring-return. Air is thus supplied cylinders 114 to retract slides 98 to the position illustrated in FIG. 4A. It will be appreciated that slides 92, 96 and 98 lie in the position illustrated in FIG. 4E and that the circuit is now in condition for initiation of another feed cycle upon closing command switch 154.  
  Another form of magazine feed machine 10 is illustrated in FIGS. 7 and 8. In this form, pairs of helixes mounted on shafts or augers 200 are spaced one from the other to define a chute therebetween for receiving a stack of connector plate stock. The augers are rotated in synchronism one with the other by means of gears 202, 204. The helical projections engage the lateral edges of paired lengths of connector plate stock in the stack thereof and it will be appreciated that the rotation of the augers continuously lowers the stack toward a feeding mechanism generally indicated 206. This mechanism includes upper and lower slide elements 208 and 210 under the control of a pneumatic cylinder 212. Elements 208 and 210 are disposed for movement within upper and lower slots 211 and 213 respectively of a support block 214 for disposing upper and lower plates in feed positions 216 and 218 respectively. The upper slide element 208 has a step 220 at its end for receiving successive plates from the stack. Laterally adjacent upper element 208 is a guide surface 222 which is defined along respective opposite edges by an inwardly extending lip 224 and a spring-biased plunger or guide 226. A lower support block 227 forms a guide surface 228 for the lower surface of slide element 208. A plurality of upstanding pins 230 project from surface 228 at longitudinally spaced positions therealong. The lower slide element 210 lies along a lower surface 232,  
 the feed position 218 of which is defined by a stop 234 and a spring-biased wedge element 236.  
  In operation, and referring to FIG. 7A, a pair of plates in back-to-back relation are dropped from the helical gears 200 onto step 220 of upper slide element 208, the lower plate having its teeth facing downwardly while the upper plate has its teeth facing upwardly. Cylinder 212 is actuated to displace slide elements 208, 210 to the right as illustrated in FIG. 7A whereupon the lower plate P1 is carried on step 220 for disposition in feeding position 216. Particularly. as illustrated in FIG. 7B. the upper plate P1 is engaged by lip 224 and by the spring-biased element 226. Also, the pins 230 extend between the transverse rows of teeth of plate P1 and serve to maintain plate P1 in an elevated position spaced from surface 228 when the element 208 is retracted as illustrated in FIG. 7C. While the elements 208 and 210 are in the position illustrated in FIG. 7B, lower plate P2 slides on the top surface of element 208. Upon retraction of elements 208 and 210 such that their leading edges lie out of alignment with the stack, the plate P2 drops onto surface 232 as illustrated in FIG. 7D. The cylinder 212 is again actuated to advance elements 208 and 210 whereupon step 220 slides below the teeth of plate Pl which is maintained elevated above surface 223 as previously noted. Slide element 210, however, displaces the lower plate P2 into feed positions 216 and 218. The elements 208 and 210 in the meantime, upon retraction of cylinder 212, return to the position illustrated in FIG. 7A whereupon a next pair of lengths of connector plate stock are dropped from augers 200 onto the stepped portion 220 of element 208 and the cycle is repeated.  
  The invention may be embodied in other specific forms without departing from the spirit or essential characteristics thereof. foregoing present embodiments are therefore to be considered in all respects as illustrative and not restrictive, the scope of the invention being indicated by the appended claims rather than by the foregoing description, and all changes which come within the meaning and range of equivalency of the claims are therefore intended to be embraced therein.  
  What is claimed and desired to be secured by United States Letters Patent is:  
  1. Apparatus for feeding a plurality of strips of stacked connector plate stock to a fabrication machine, each strip being formed of sheet metal with a plurality of teeth struck to project to one side thereof comprising: first and second surfaces spaced one from the other and defining first and second positions for feeding a pair of strips of connector plate stock to the machine, means for guiding the stacked strips of stock for movement toward said first and second feed positions. means. carried by said apparatus for locating a first pair of strips in said first and second feed positions respectively including means for separating the first pair of connector plate stock strips one from the other and from the stack thereof, means for restraining the stacked strips of connector plate stock next adjacent the first pair thereof from movement toward said first and second feed positions while the first pair of strips are located in said feed positions, and means for displacing the pair of strips from said feed positions in a direction other than the direction of movement of the stacked strips toward said first and second positions for feeding the first pair of strips to the machine.  
  2. Apparatus according to claim 1 wherein said locating means includes means for gripping the next to the end strip of the first pair of strips.  
  3. Apparatus according to claim 1 wherein said restraining means includes an element engageable with the teeth of the strip in the stack next adjacent the first pair of strips.  
  4. Apparatus according to claim 1 wherein the strips are stacked vertically, said first and second surfaces comprising vertically spaced generally horizontal surfaces with said first surface spaced below said second surface.  
  5. Apparatus according to claim 4 wherein said second surface is defined by a first clement movable into and out of engagement with the stacked strips, said separating means including a second element spaced above said first element and movable into and out of engagement with the upper strip of the first pair of strips to respectively support and release the latter, means for moving said second element into and out of engagement with such upper strip, and means for moving said first element into engagement with the stack of strips to support the same and for moving said first element from supportive position therefor when said second element engages the upper strip of the first pair of strips, the lower strip of the first pair thereof being movable into said first feed position in response to movement of said first element from the supportive position relative to said stack.  
  6. Apparatus according to claim 5 wherein said restraining means includes a third element spaced above said second element and movable into and out of engagement with the stack of strips, said third element being movable into engagement with the strip next above the leading pair of strips to support it and the stack above. and means for moving said second element into engagement with the strip next above the first pair thereof for supporting the stack while the first pair of strips are located in said first and second feeding positions.  
  7. Apparatus according to claim 6 including means responsive to locating the first strip in said first feeding position for moving said second surface into the vertical confines of the stack and below the upper plate, said moving means for said second element being adapted to move said second element out of the vertical confines of the stack to release the upper strip of the first pair thereof for movement onto said first surface.  
  8. Apparatus for feeding a plurality of strips of stacked connector plate stock to a fabrication machine, each strip being formed of sheet metal with a plurality of teeth struck to project to one side thereof comprising: first and second vertically spaced surfaces defining positions for feeding a pair of strips of connector plate stock to the machine, means for guiding the stacked strips of stock for vertical movement toward said first and second feed positions, first, second, and third vertically spaced superposed pairs of elements spaced above said first feed position with the elements of each pair thereof movable toward and away from one another between extended and retracted positions respectively and located on respective opposite sides of said guide means, the surface of said first pair of elements when in said extended position thereof defining said second feed position spaced above said first feed position, means for moving said pairs of elements for locatl2 ing a first pair of strips from the stack thereof in respective first and second feed positions including means for extending said second and third pairs of elements into engagement with the stock with the lowermost strip being supported by the extended first pair of elements, means for retracting said first pair of elements to drop the lowermost strip onto the surface defining said first feed position while the stack of strips is supported by the extended second and third pairs of elements, and means for extending said first pair of elements below the stack of strips and retracting said second pair of elements to drop the next to the lowermost strip onto the extended first pair of elements and into said second feed position with the stack being supported by the extended third pair of elements.  
  9. Apparatus according to claim 8 wherein said second and third pairs of elements each have a pair of projections for engaging below the strips and between the teeth thereof.  
  10. Apparatus according to claim 8 wherein each of the elements of said third pair thereof has a surface for engaging the teeth of the strips.  
  11. Apparatus according to claim 8 including means for displacing the strips from said first and second feed positions for delivery to the machine.  
  12. Apparatus according to claim 8 including means for sensing the disposition of the lowermost strip in said first feed position and providing a signal in response thereto, and means responsive to said signal to extend said first pair of elements and subsequently retract said second pair of elements.  
  13. Apparatus according to claim 12 including means for displacing the strips from said first and second feed positions for delivery to the machine in response to re traction of said second pair of elements.  
  14. Apparatus for feeding a plurality of strips of stacked connector plate stock to a fabrication machine, each strip being formed of sheet metal with a plurality of teeth struck to project to one side thereof comprising first and second vertically spaced positions for feeding a pair of strips of the connector plate stock to the machine, a pair of laterally spaced elements each having a helix thereon defining support surfaces for stacked strips of connector plate stock disposed therebetween, means for rotating said elements to lower the stack of strips, first and second vertically spaced slides mounted for lateral movement between retracted and extended positions and below said elements, said first slide having a surface for receiving a strip dropped from between said elements, means for displacing said slide laterally in opposite directions to respectively locate the strip in the first feed position and to retract the slide therefrom and from below the superposed stack of strips, means for guiding the next strip dropped from the stack thereof into lateral juxtaposition with said second slide when the first slide lies in said retracted position, means for displacing said second slide laterally in opposite directions to respectively locate the latter strip in said second feed position and to retract the slide therefrom.  
  15. Apparatus according to claim 14 including means for retaining the strips in said first and second feed positions respectively upon retraction of said slides.  
  16. A method of feeding a plurality of strips of stacked connector plate stock to a fabrication machine, each strip being formed of sheet metal with a plurality of teeth struck to project to one side thereof comprising the steps of arranging the strips of stock in the stack in pairs thereof with the teeth of the plates of each pair extending toward one another. supporting the stack of connector stock with the lowermost strip in a second feed position. dropping the lowermost strip from said second feed position to a first feed position while simultaneously supporting the stack of strips above said first and second positions. dropping the next to the lowermost strip from the stack into the second feed position while simultaneously supporting the superposed stack in vertical spaced relation above said second feed position, and displacing the strips of connector plate stock from said first and second feed positions.  
  17. A method of feeding a plurality of strips of stacked connector plate stock to a fabrication machine, each strip being formed of sheet metal with a plurality of teeth struck to project to one side thereof comprising the steps of locating a stack of strips of connector plate stock between a pair of elements having helical surfaces whereby the strips are supported by the helical surfaces, rotating the elements to conjointly lower the stack of strips. dropping the lowermost strip onto a slide, displacing the slide laterally for disposing the lowermost strip in a first feed position. retracting the slide from the feed position and from below the stack of strips. dropping the next striponto a surface spaced below the first feed position. displacing a second slide laterally to locate said next strip in a second feed position in general vertical registry below the first feed position. and retracting said second slide from said second feed position and from below the stack of strips.  
  UNITED STATES PATENT OFFICE CERTIFICATE OF CORRECTION Patent No. 3,877,608 Dated April 5, 5  
 l v t John Calvin Jureit, Ben Kushner, Roy Leutwyler and Adolfo Castillo It is certified that error appears in the above-identified patent and that said Letters Patent are hereby corrected as shown below:  
 Col. &#39;6, line 65, &#34;and p2&#34; should read --and P2--. Col. 8, line 4, &#34;line 166 supply&#34; should read --line 166 across supply--.  
 Col. 10, line 37, &#34;thereof. foregoing&#34; should read thereof.  
 The  
 Signed and Scaled this seventh&#39; Day of October 1975 [SEAL] Attest:  
 RUTH C. MASON C. MARSHALL DANN Arresting Officer Commissioner ofParenls and Trademarks