US2947329A - Loop fastener machine control apparatus - Google Patents

Description

Aug. 2, 1960 n. s. KINGsLEY LOOP FASTENER MACHINE CONTROL APPARATUS Qui NQ ATTO XN, SN` Q0, l

Filed Sept. 26, 1957 Aug. 2, 1960 D. G. KlNGsLEY LOOAD FASTENER MACHINE CONTROL APPARATUS 5 Sheets-Sheet 2 Filed Sept. 26, 1957 INVENTOR. Qavc Kzlnsley BY xo N lill

5 Sheets-Sheet 3 D. G. KINGSLEY Aug. 2, 1960 Loop FASTENER MACHINE CONTROL APPARATUS Filed sept. 26, 1957 W\\\\\\\\\\ Q L Y v m e .m 1

Aug. 2, 1960 D. G. KINGsLEY LOOP PASTENER MACHINE CONTROL APPARATUS 5 Sheets-Sheet 4 Filed Sept. 26, 1957 INVENTOZR. avic Kin s e BY y 7m@ c ATTO :T 15. T 114-. /wz n WL /fz u] Aug. 2, 1960 D. G. KxNGsLEY 2,947,329

LOOP FASTENER MACHINE CONTROL. APPARATUS Filed sept. 26, 1957 5 sheets-sheet 5 @if T1-:1.11. 1a.

INVENTOR.

,D 'd .Kzl sie BYavL g y a'@ Patented Aug. 2 1960 LOOP FASTENER MCE CNTRL APPARATUS David G. Kingsley, Mountain Lakes, NJ., assigner to Stapling Machines Co., Rockaway, NJ., a corporation of Delaware Filed Sept, 26, 1957, Ser. No. 686,487

5 Claims. (Cl. 14093) This invention relates to apparatus for controlling the lengths of the loop fasteners produced on wirebound box parts in a loop fastener machine, for example loop fastener machine of the general type disclosed in U.S. Patent No. 1,933,031 issued October 31, 1933 and No. 2,228,304 issued January 14, 1941.

Such loop fastener machines are intended for use in combination With box-part stapling machines of the general type disclosed in U.S. Patent No. 2,304,510 issued December 8, 1942. In the stapling machines, the wooden elements of the box-for example, cleats and face material-are assembled and binding wires are secured thereto by staples driven astride the binding wires through the face material and into the cleats. The box parts (or complete box blanks) issue from the stapling machine in a continuous succession joined together by the binding wires, with sufcient space between adjacent box parts to pnovide the necessary lengths of wire for forming the loop fasteners at either end of each box part. This continuous succession of box parts is fed into the loop fastener machine where the binding wires are severed in the interval between adjacent box parts, the resulting cut wire ends are bent to form downwardly projecting prongs, the binding wires are then bent around in the plane of the box parts to form loops therein and to place the prongs over the edges of the box parts, and the prongs are then driven through the face material and clinched against the under surface thereof to secure the loop,VV

fasteners.

In certain types of wirebound containers, the closed loop fasteners overlie the faces of the containers some distance from the corners. To achieve this condition, it is necessary that the loop fasteners on one of the adjoining box parts be shorter than the mating fasteners on the other box part. For example, it may be desired that the loop fasteners on the top and bottom of the box be longer than the mating fasteners on the sides of the box so that the closed loop fasteners will overlie the sides of the box.

In making containers of this type heretofore, it has been necessary to set up the loop fastener machine to make loops of the proper length for one of the two types of box parts needed for a complete box and to run enough of such box parts for an entire lot without resetting the machine. For example, the machine is rst set up to run tops and bottoms and enough tops and bottoms are run to make a complete shipment; then the box fastener machine is reset to run sides. This necessitates the provision of considerable storage space for storing the completed box parts of one type until the other type of box parts can be run to complete the shipment.

lt is among the objects of the present invention to provide apparatus for controlling a wirebound loop fastener machine whereby the machine can be adapted to form loop fasteners of different lengths in successive cycles, so that equal numbers of two different types of box parts can be run concurrently on a single loop fastener machine without manual resetting of the machine. Another object is the provision of such an apparatus which is relatively simple and inexpensive in construction and which is adapted to be installed readily on existing loop fastener machines, without substantial reconstruc-v tion thereof. A further object is that of providing such an apparatus which is reliable in operation and which is capable of accurate control of the length of the loop fasteners. Other objects will be apparent hereinafter.

In the drawings: Y

Figure 1 is a fragmentary top plan view of a loop` fastener machine incorporating control apparatus enrbodying features yof the present invention.

Figure 2 is a fragmentary vertical-longitudinal sectional view of the machine taken generally along the line 2-2 of Figure 1. g

Figure 3 is a fragmentary top elevational view of the portion of the mechanism shown in Figure 2.

Figures 4 `and 5 are transverse sectional `views taken respectively along the lines 4-4 and 5-5 of Figure 2.

Figure 6 is a fragmentary vertical-longitudinal sectional view of the machine taken generally along the line 6-6 of Figure 1.

Figure 7 is atransverse sectional View taken along the line 7--7 of Figure 6.

Figure 8 is a fragmentary top elevational View of the portion of the mechanism shown in Figure 6.

Figure 9 is a fragmentary vertical-longitudinal sectional view taken generally along the lines 9-9 of Figure 1, and forming an eifective continuation of the view of Figure 6.

Figure 10 is a fragmentary top elevational View of the portion of the mechanism shown in Figure 9.

Figures 11 and 12 are fragmentary vertical-transverse sectional views of the machine taken respectively along the lines Ill- 11 and 12-12 of Figure l.

Figures 13 and 14 are schematic diagrams of two alternative electrical circuits for control apparatus within the scope of this invention.

In Figure 1, a continuous succession of box parts B joined together by binding wires W is seen moving into the loop fastener machine. The box parts B are supported in the machine on a table generally designated T, and are conveyed through the machine by means of conveyor belts C which frictionally engage the lateral edges of the box parts. When the box parts reach the position shown in Figure l, at which the binding wires W in the interval between adjacent box parts are in proper position to be operated upon by the wire cutting and forming elements of the machine, the conveyor belts C are momentarily stopped and the table T is lowered to present the binding wires to the wire cutting yand forming elements, which are actuated to sever the binding wires, form the pnongs, bend the loops and drive and clinch the prongs. Upon completion of this operation, the table T is again raised and the movement of the conveyor belt C is resumed to deliver the completed box parts out of the machine.

As will readily be understood, the position in which the work is stopped determines the lengths of the loop fasteners which are formed on the ends of the binding wires projecting from the adjacent box parts within the machine. For example, if the work is stopped at a point beyond that at which the binding wires in the interval between the adjacent box parts are exactly centered relative to the wire cutting and forming elements, the loop fasteners on the leading box part will be longer than those on the trailing box part. Conversely, if the work is stopped short of the point at which the binding wires are centered relative to the wire cutting and forming e1e` ments, the loop fasteners on the leading box partwill be shorter than those on the trailing box part. In general terms, the presentv invention provides means for stopping the work in different positions on alternate cycles of the machine so that the machine will produce, in alternation, box parts having at each end loops of shorter and longer lengths. Y j Y Figures 2, 3, 4 and 5 show the mounting of the switch which conditions the control apparatus for operation. This switch, whichV is referred tohereinafter as the yready switch, is identified by the reference numeral 20. It is mounted on a plate 22 which is supported for longitudinal sliding movement on one of the Vstock support bars 24 which are adjustably secured at either end by means of bolts 26 and nuts 28 on the two dual-channel members 30 which form the principal transverse framing members of the table T (Figure 1). The plate 22 is slidably supported at one face of the bar 24 by means of bolts 32 and nuts 34 (Figure 5). Mounted on the bolts 32 within the elongated opening 24a (Figure 2) in the work support bar 24, are bushing sleeves 34a (Figure 5) which are interposed between the nuts 34 and the face of the plate 22 to prevent tightening of the nuts against the work support bar 24 and thereby insure that the switch plate 22 may slide freely along the bar 24. Y

' For the purpose of adjusting the position of the switch plate 22 relative to the work support bar 24, there is attached to and extending longitudinally from the rear end of the switch plate 22, an elongated rod 38 the outer end of which is bent to form a handle 38a which is in convenient position to be grasped from the output end of the machine.V The switch plate 22 is locked in the adjusted position by means of a clamp 40 (Figures 2 and 4) which is Vsupported on a'stud 42 threaded into the work support bar 24, the outer face of the clamp 40 being engaged by a nut 44 threaded on the stud 42 for the purpose of applying gripping pressure to the rod 38 between the clamp V40 and work support bar 24.

The switch 20 is actuated by means of a lever 46 which is pivotally mounted on a bolt 4S projecting from the outer face of the switch plate 22. The lever 46 is urged in a clockwise direction, as viewed in Figure 2, by means of a coil spring 50 which is compressed between the lower end of the lever and a tab 52a projecting upwardly from a bracket 52 secured to the outer face of switch plate 22 by screws 54. The clockwise movement of lever 46 under the influence of spring Sil is limited by engagement of the lower end of lever 46 with a stop screw 56 adjustably threaded through a tab 52h projecting upwardly from the bracket 52. Y Y

The spring 50 thus tends to maintain the lever 46 in the position indicated in broken lines in Figure 2 at which the upper end of the'lever projects into the path of the face material F of the box parts B (Figure 1), moving lintoand through the loop fastener machine in the direction indicated by the arrow at the upper right-hand side of Figure 2. In this upper position of lever 46, an adjustable switch actuating screw 62 threaded through a boss `64 in the lower portion of lever 46 depresses the plunger 20a of ready switch `20.

However, the upper end of the lever 46 is rocked in a counterclockwise direction to the position shown in full lines in Figure 2 and held down in such'position by engagement of the upper end of the lever with the face material F of a box part B moving into and through the loop fastener machine. In this depressed' position the screw 62 of leverV 46 will release the plunger 20a of ready switch 20.

The upper end of the lever 46 is provided with a flattened portion 46a which is parallel to the lower face of the face material F of a box part resting upon the work support bar 24 when the lever 46 is in the depressed position in which it is shown in full lines in Figure 2. This Hattened portion 46a is sufficiently long that the lever 46 cannot move upwardly except in the interval between adjacent box blanks in other words, the length of the portion 446a is greater than the greatest-spacing between the slots of any crate construction to be handled in the machine. Thus, the plunger 20a of ready switch 20 will be depressed at all times during the operation of the machine except during passage of a space between separate box parts or box blanks.

lAs will be more fullyrdescribed hereinafter, the switch 20 is connected to control the supply of compressed air to a pair of pneumatic cylinders, one of these cylinders being identied by the reference numeral 66 in Figure 6. These two cylinders formparts of two identical vstopswitch mechanisms which are mounted on the table T of the machine for engagement with opposite ends of the leading edge of each box part or box blank moving into the machine; Since these two mechanisms are identical, only one of them is shown and described.

For handling box parts and blanks of relatively small width, only one of these mechanisms need be provided. But where the box parts or box blanks are of relatively great width, greater accuracy of loop length can be achieved by using two such mechanisms,V one near either end of the box parts or blanks.

As may be seen in Figure 6, each of the stop-switch mechanisms includes a work Vsupport bar 70 which is adapted to engage the undersurface of the facematerial F of the'box part B near one side thereof. The work support bar 70 is mounted for longitudinal movement in a pair of blocks 72, one of which is shown at the right in Figure 6 and the other of which is shown inV Figure 9, these two blocks being secured on the transverse members 30 of the table T (tFigure 1). To provide forlongitudinal movement of the work support bar 70, the bar carries at each end a set of four rollers 74, Ytwo at either side, which are rotatably mounted on bolts 76. TheA rollers 74 are received in guide slots 72a in the blocks 72, the slots 72a being of a width only slightly greater than the diameter of the rollers '74 to confine the rollers against vertical movement while permitting them to roll along the slots for longitudinal movement of the bar 70 relative to the blocks 72.

To limit the longitudinal movement of the bar 7i), there are provided a pair of stop screws 78 (Figures 6 and 9) which are adjustably threaded Ithrough tabs 80 projecting laterally from the bar 70. The heads or these screws are adapted for engagement with the inner ends of the blocks 72 and the adjacent edges of the transverse members 30. The stop screws 78 are so adjusted that when one of them is in engagement with its respective block 72, as shown in Figure 6, the other is spaced a short distance from its respective block 72, as shown in Figure 9, and vice versa. Thus, the work support bar 70 is permitted to move longitudinally between two positions spaced apart a short distance depending upon the adjustment of the stop screws 7S.

The work support bar 70 is moved to one or the other of its two extreme positions by a pneumatic cylinder 82 (Figure 6). The outer end of the casing of this cylinder y'82 is pivotally secured by a pin `83 to a lbracket 84 depending from the forward end of an arm 86 which is secured to and extends forwardly from the underside of the transverse member 30 at the front end of the table T. The piston rod 87 of the cylinder 82 is pivotally secured by means of a clevis 88 and pin 89 to the lower end of an arm 90 which projects -downwardly from the work support bar 70 `and whose upper end is rigidly secured thereto.

By means which will be described more particularly hereafter, the pneumatic cylinders 82 of the two stopswitch mechanisms are connected for simultaneous movement of their respective work support bars in the same direction so that both of the work support bars are either in the forward position, at which they are shown in Figures 6 and 9, or are in their rearward position at which the head of the rear stop screw 78 (Figure 9) is against the rear block 72. Y Y t Secured at one face of the work support Vbarv70 is a stop switch 92 (Figures 6 and 8) the plunger 92a of which is actuated by a screw 94 adjustably threaded through the end of a U-shaped arm 96 which extends beneath the work support bar 70 'and around to its opposite side where it is attached to by means of screws 100 to a switch actuating member 98. This member 98 is pivotally attached by means of a bolt 102 and bushing 103 (see Figure 7) to the upper end of a link 104 whose lower end is pivotally attached by a bolt 106 and bushing 107 (Figure 7) to the work support bar 70. Thus the switch actuating member 98 may not only pivot about the bolt 102 but it may also move longitudinally by pivoting of the link 104 about the bolt 106.

` The switch actuating member 98 is urged forwardly (toward the right as viewed in Figure 6) by means of a coil spring 108 which is tensioned between the bolt 102 and a stud 110 projecting from the face of the work support bar 70. Forward movement `of the member 98 under the influence of the spring 108 is limited by a pin 112 which projects from the outer face of the member 98 yand engages the adjacent edge of the link 104. As will be understood, as the member 98 moves forwardly from the point at which the link 104 is perpendicular to the member 98, the angle between them decreases to the point where the `edge of the link 104 comes into abutment with the pin 112, thereby preventing further forward movement of the member 98. The member 98 may be moved rearwardly from this position, against `the resistance of the spring 108, to the point where a vertical shoulder 98a near the rear end of member 98 comes into abutment with a roller 114 which is rotatably supported on the face of member 70 by a screw 116 (Figure 8).

The member 98 is urged in a clockwise direction about its pivot bolt 102 by a coil spring 118 which is tensioned between a pin 120 projecting from the forward (right-hand) end of the member 98 and a pin 122 secured to andprojecting forwardly from the lower end of arm 90. The clockwise movement of the member 98 under .the inuence of the spring 118 is limited by engagement of the roller 114 with an upwardly facing horizontal edge portion 98h of the member 98.

Near the rearward end of the switch actuating member 98, a stop block 124 is secured to the upper edge of the member 98 and projects upwardly therefrom in position, when the member 98 is in its extreme clockwise position, as shown in Figure 6, to engage the leading edge of the face material F of each box part moving into the machine. However, the stop block 124 may be removed from the path of the face material F by rocking the member 98 in a counterclockwise direction about its pivot bolt 102 against the resistance of the spring 118. This is accomplished by the pneumatic cylinder 66 previously referred to. The casing of the cylinder 66 is secured to the arm 90 which projects downwardly from the work support bar 70, while the piston rod 126- of the cylinder 66 has secured at its upper end a finger 128 which overlaps the outer face of the member 98 at its right-hand end and which carries a roller 138 which is adapted to engage ia generally horizontal lower edge 98C of the member 98 when compressed air is supplied to the cylinder `66 to raise its piston rod 126. Such movement of the piston rod 126 rocks the member 98 in a counterclockwise direction 'against the resistance of the spring 118 and removes the stop block 124 from 'the path of the face material F of the box parts. t1/hen the supply of compressed airis removed from the cylinder 66, the spring 118 rocks the member 98 again in a clockwise direction to the position shown in Figure 6 at which the stop block 124 is in position to engage the leading Vedge of the face material F.

When the stop block 124 is thus engaged by the leading `edge of the face material F of a box part B moving into the machine, the "member 98 is moved rearwardly (to the left as shown in Figure 6) to the point where the shoulder 98a of the member 98 engages the roller 114 on the work support bar 70. During this rearward movement of the member 98, the screw `94 (Figure 8) depresses the plunger 92a of the stop switch 92, actuating the switch which, through a circuit to be described hereinafter, stops the movement of the conveyor belts and causes the table T and the wire cutting and forming elements of the machine to be driventhrough a loop forming cycle.

Two additional switches which play a part in the electrical control circuit for the apparatus are shown in Figures 11 and 12. The switch shown in Figure 11, which is referred to hereinafter as the reset switch, is identiiied by the reference numeral 132. It is mounted on a bracket 134 secured to the forward end of one of the two side frames 136 of the machine (see also Figure 1). The plunger 132er of the switch is actuated by means of a screw 138 which is adjustably threaded through an arm 140 secured to the adjacent longitudinal framing member 142 of the table T. When table T is in its normal upper position, in which it is shown in Figure 1l, the screw 138 depresses the plunger 1325.1. When, at the start of the loop forming cycle, the table T is lowered to present the box parts to the wire cutting and forming elements of the machine, the screw 138 releases the plunger 13251.

The switch shown in Figure l2, which is an indexing switch-Le., it is opened and closed on alternate actuations-is identified by the reference numeral 144. This switch 144 is mounted on a plate 146 which is secured at the rearward end of the side frame 136 previously referred to (see also Figure l). This switch 144 is provided with a laterally projecting pivotally mounted arm 144g which carries at its outer end a roller 14411 which lies in the path of a block 148 carried at the outer end of an arm 150 secured near the rearward end of the aforementioned longitudinal framing member 142 of the table T. Each time the table T descends from its normal uppe position, in which it is shown in Figure 12, the inclined lower end 148a of the block 148 comes into engagement with the roller 1441: on the actuating arm 14451 of the switch 144, rocking the arm 144a in a counterclockwise direction, as viewed in Figure 12, and indexing the switch from one position to the next. 1

Figure 13 shows one illustrative electrical circuit for the control apparatus. In Figure 13 this electrical circuit is shown in the condition which obtains in the interval between loop forming cycles, prior to the arrival into the machine of the interval between the next. pair of box parts to be operated upon. As may be seen, the ready switch 20, which is a normally open single-pole singlethrow switch, is closed by Virtue of the fact that the lever 46 (Figure 2) is held in the lower position in which it is shown in full lines in Figure 2 by engagement with the undersurface or' the face material F of a box part moving through the machine, causing the screw 62 to depress the plunger 20a of the switch. The closure of this switch 20 maintains the supply of current from the power lines 152 and 154 (Figure 13) through the winding 156:1 of a relay 156, the normally open holding contacts 15@ of the relay being held closed by the energization of the winding 15661. The relay 156 is also provided with another pair of normally open contacts 156C which are closed by the energization of the winding 156g and these closed contacts 156C supply current from the power lines 152 and 154 to the winding 158 of the solenoid valve which controls the supply of compressed air to the cylinder 66 (Figure 6). When this winding 158 is thus energized, compressed air is supplied to the cylinder 66 to maintain its piston rod 126 in an upper position and hold the switch actuating member 98 rocked in a counterclockwise direction against the resistance of the spring 118, thereby holding the stop block 124 out of the path of the face material F of the box parts moving through the machine.

When the interval between the next pair of box parts to be operated upon in the machine comes opposite the lever `46` (Figure 2) the lever 46 is allowed to be moved in a clockwise direction by the spring 50 to the position shown in broken lines in Figure 2, releasing the plunger a of the ready switch 20 and opening the switch. As may be seen in Figure 13, the opening of the ready switch 20 breaks the circuit to the winding 156a of the relay 156 and opens its contacts 156b and 156er. The opening of the holding 'contacts 156b prevents reenergization of the relay winding'156a until the next Vtime the reset switch 132 is closed, even though the switch 20 will have been reclosed in the meantime. The opening ofthe relay `contacts 156C breaks the circuit to the Winding 158 of the solenoid valve and removes the ysupply of cornpressed air from the cylinder 66 (Figure 6). This permits the spring 118 to rock the switch actuating member 98 in a clockwise direction to the position shown in Figure 6 at which the stop block 124 is in the path of the face material F of the oncoming box part.

When the leading edge of the face material F of the oncoming box part engages the stop block 124, the switchactuating member v98 is moved rearwardly (to the left as viewed in Figure 6) against the resistance of the spring 108 to the point where 4the shoulder 98a comes into abutment with the roller 114. During this movement of the member 9S, the stop switch 92 is closed Referring again to Figure 13, the closure of the stop switch 92, which is a normally open single-pole single-throw switch, supplies current from Vthe power lines 152 and 154 to the Winding 160a of a relay 160. This closes the normally open contacts 160b and 160C of the relay 160 and supplies current from the power lines 152 and 154 to a pair of solenoids 162 and 164 which control the clutches which drive the conveyor belts C (Figure 1), the table T and the Wire cutting and forming elements of the machine. Energization of the solenoid 162 disengages the clutch which drives the conveyor belts C and applies the brakes to stop the conveyor belts and thereby stop the movement of the box parts B. Energization of the solenoid 164 engages the clutch which drives the table T and the Wire cutting and forming elements of the machine. This clutch is of the type which, once engaged, remains engaged for one complete revolution and is then automatically disengaged. When this clutch is engaged, it causes the table T to be lowered to present the binding wires to the Wire cutting and forming elements and causes the latter elements to be driven through a loop forming cycle to sever the wire, bend the resulting cut wire ends to form prongs, bend the wires again to form loops therein and to place the prongs vover the edges of the face material of the box parts to drive the prongs through the face material and clinch them over against the undersurface thereof. The construction and `operation of these clutches is ydescribed in greater detail inthe aforementioned Patent No. 1,933,031.

As the table T is Vlowered at the commencement of the loop forming cycle, the plunger 132z (Figure 11) of the reset switch 132 is released, allowing this switch 132, which is a normally closed single-pole single-throw switch, to close. As many be seen in Figure 13, the closure of this reset switch 132 supplies current to the winding 15651 of the relay 156 energizing the relay and closing its normally open contacts 156b and 156e.

r[The closure of the holding contacts 15611 maintains the energization of the winding 15601 of the relay 156 through the ready Yswitch 20, which by now will have been reclosed by depression of the lever 46 (Figure 2) by engagement with the undersurface of the face material F. Thus, even after the switch 132 is reopened by return of the table T to its normal upper position at the conclusion of the loop forming cycle, the relay 156 will remain energized preparatory for the next cycle.

The closure of contacts 156C of relay 156 again energizes therwinding 158 of the solenoid valve which controls the supply of compressed air to thecylinder 66 (Figure 6). `This causes compressed air to be supplied to cylinder 66, raising its-piston rod 126 and rocking Athe member 98 in a counter-clocklwse direction about its pivot bolt 102. against the resistance of spring 118 to the point where stop block 124 is removed from-the path of the face material F. This readies the machine for resumption of the feeding of box parts B-uponcompletion of the loop forming cycle.

As the stop block 124 moves out of engagement-with the leading edge of the face material F, the spr-ing 108 again moves the switch actuating member 98 forwardly, causing the screw 94 (Figure 8) to release the plunger 92a of the stop switch 92 and open the switch. Asmay be seen in Figure 13, the opening of stop switch 92 deenergizes the relay 160, opening its contacts `b and 169C. solenoid 162 of the clutch which-drives the conveyor belts C (Figure 1). However, this clutch is heldout of engagement during the entire time the table T is lowered by a mechanical interlock more fully disclosed in the aforementioned Patent No. 1,933,031. Although the opening of the contacts 160e deenergizes the solenoid 164 of the clutch which drives the table and the wire cutting and forming elements of the machine, as mentioned hereinabove this clutch will remain engaged for one full revolution of the drive shaft, and these elements will be driven through a complete loop forming cycle before stopping. Y

The lowering of the table T at the commencement of each loop forming cycle actuates the indexing switch 144 (-see also Figure l2) from one position to the next. This switch 144 is thus open during one loop forming cycle and closed during the next.

As may be seen in Figure 13, the s'witch 144 is connected in series, `across the power Ylines 152 `and-154, with the winding 166 of the solenoid valve which controls the supply of compressed air to the pneumatic cylinder 82 (Figure 6). 'Thus this solenoid valveis open during one loop forming cycle and closed during the next, to cause the cylinders 82 to shift the two Work support bars`7 0 in unison to their extreme forward position as shown in Figure 6 on one loop forming cycle and to their extreme rear position on the next. This changes the positions of the stop block 124 and causes the work to be stopped in different positions on alternate cycles. Thus the machine will produce, in alternation, box parts having short loops at each end and box parts having long loops at each end.

As the loop forming cycle is completed, the table T is again raised and the mechanical interlock of the clutch which controls the drive to the conveyor belts C is released, allowing the movement of the conveyor belts to be resumed to :feed the completed box parts out of the machine. The electrical circuit is then in the condition in which it is shown in Figure 13, and is ready for the next cycle.

Figure 14 illustrates an alternative electrical circuit which is. employed in a modified embodiment of the present invention. In this embodiment, the two stopswitch mechanisms, rather than being shifted simultaneously to their forward and rearward positions, are fixed in position, one in its extreme forward position and one in its extreme rearward position. As will be understood, in this embodiment the work support bars 70 (Figures 6 and 9) need not be moved between successive cycles of the machine, and may be fixed in position. lThis eliminates the .need for the pneumatic cylinders 82 (Figure 6) which shift these stopswitch assemblies between their respective positions, and for the rollers 74 which facilitate such movement. Instead a simple clamping arrangement such as is provided for the ready switch mechanism (Figure 2) may beprovided to permit adjustment of the positions of the stop switch :assemblies for variation of the loop lengths. Sincethe two stop-switch mechanisms-are ini diier-` The opening of contacts 160b deenergizcs the ent positions, their respective stop blocks (Figure 6) are displaced relative to each other longitudinally of the machine. By means of the circuit shown in Figure 14, rst one and then the other of the two stop blocks is moved into position to engage the face matenial F of the box parts B.

In Figure 14 the circuit is shown in the condition which obtains prior to arrival in the machine of an interval between adjacent box parts to be operated upon. The ready switch 20 is closed to energize the relay 156 through its closed holding contacts 156b, The energization of the relay 156 also maintains its contacts 156e closed to supply current through the contacts 170e of a double-pole double-throw indexing switch 170 to the winding 172 of the solenoid valve which controls the supply of compressed air to the cylinder 66 (Figure 6) of one of the two stop-switch mechanisms. The winding 174 of the solenoid Valve which controls the supply of lair to the cylinder 66 of the other stop switch mechanism is also energized through the other contacts 170b of the indexing switch `170. Thus, compressed air is supplied to the cylinders 66 of both of the two stopswitch mechanisms to maintain their stop blocks 124 out of the path of the oncoming box parts.

When the box parts have advanced to the point where the space between adjacent box parts or box blanks is opposite the lever 46 (Figure 2) of the ready switch 20, the lever will move upwardly into this space, depressing the plunger 20a of the ready switch 20 and opening the switch. As may be seen in Figure 14, the opening of ready switch 20 will deenergize relay 156, opening its contacts 15611 and 156e. The opening of contacts 156C will deenergize winding 172 and allow the stop block 124 (Figure 6) of one of the two stop-switch mechanisms to be moved upwardly by spring 118 into the path of the leading edge of the face material F of the oncoming box part. When this stop block 124 is thus engaged and moved rearwardly, against the resistance of the spring 108, the stop switch 92 (Figure 14) will be closed, energizing relay 160 and closing its contacts 160b and 160C to actuate the solenoids 162 and 164 which control the clutches which drive the conveyor belts C (Figure l), the table T and the wire cutting and forming elements of the machine. Thus, as previously described, the conveyor belts will be stopped, the table lowered and the machine will be driven through a loop forming cycle.

As the table T is lowered, a reset switch 132 will be closed, again energizing relay 156, closing its contacts 156e and energizing the winding 172 of the solenoid valve which controls the supply of compressed air to cylinder 66 (Figure 6). This will cause compressed air to be supplied to cylinder 66, again moving the active stop block -124 from the path of the box parts so that the box parts may be delivered out of the machine when the movement of the conveyor belts C is resumed.

The lowering of table T will also actuate the indexing switch 170, in the manner previously described in connection with switch 144 (fFigure 12), to throw it from the position show-n in :Figure 14 to its `alternate position, transposing the connections of the windings 172 and 174 of the solenoid valves of the two stop switch mechanisms. Thus, on the next cycle of the machine the opening of the ready switch 20 will deenergize the winding 174 of the solenoid valve of the other stop switch mechanism to remove the supply of compressed air from its cylinder 66 (Figure 6) and allow its stop block 124 to be moved into operative position.

It will thus be seen that on one cycle of the machine one of the two stop blocks is in operative position to engage and stop the box parts, while on the next cycle the stop block 124 of the other stop switch assembly is in operative position. Thus, on one cycle the box parts are stopped in one position and on the next cycle they are stopped in the other position, so that box parts having 10 long loops and box parts having short'loops are produced on alternate cycles of the machine.

From the foregoing description, it will be appreciated that the present invention provides apparatus for automatically controlling the length of the loops being produced in the loop fastener machine to accomplish the aforementioned and other desirable objectives. However, it should be emphasized that the particular embodiments of the invention which are shown and described herein are intended as merely illustrative of the principles of the invention rather than as restrictive of the scope thereof or of the coverage of this patent, which is limited only by the appended claims.

ln some of the claims, the cylinder 66 (lFigure 6) is referred to `as the first power means and the cylinder 82 (Figure 6) is referred to as the second power means. The switch Ztl (Figures 2 and 3) is referred to as the first control means and as the ready switc switch 132 (Figures 1 and 1l) is referred to as the second control means and as the reset switch; and switch 144 (Figures 1 and `12) is referred to as the third control means and as the selector switc I claim:

l. AIn a machine for forming loop fasteners from binding wires interconnecting a spaced series of wirebound box parts, apparatus for adapting said machine to form loop fasteners of different lengths in successive cycles comprising, a stop assembly -mounted in said machine for longitudinal movement, said stop assembly including a movable stop element positioned for engagement with a predetermined portion of each box part moving into said machine, a stop switch actuated by said stop ele-V ment, said stop switch being connected to control the work feeding and loop forming mechanisms of said machine, whereby actuation of said stop switch by said box parts renders said feeding mechanism ineffective to feed the box parts and causes said loop forming mechanism to be driven through a loop forming cycle, power means for moving said stop assembly longitudinally between two positions, at which said stop element will respectively actuate said stop switch to stop said wirebound box blanks with the toop forming mechanism at opposite sides of the center of a space between adjacent box parts, and control means for controlling said power means, said control means being mounted on said machine in such position as to be engaged and actuated by a relatively movable part therein during each loop forming cycle of said machine to cause said power means to shift said stop assembly to alternate ones of said two positions on successive cycles.

2. ln a Lmachine for forming loop fasteners from binding wires interconnecting a spaced series of wirebound box parts, apparatus for adapting said machin-e to form loop fasteners of different lengths in successive cycles comprising, a stop assembly mounted in said machine for longitudinal movement, said stop assembly including a stop element which is vertically movable between an extended position at which it projects into the path of a leading `edge of said box parts and a retracted position clear of said path and which is also longitudinally movable by engagement with the moving box parts, a stop switch actuated by the longitudinal movement of said stop element, said stop switch being connected to control the work feeding and loop forming mechanisms of said machine, whereby actuation of said stop switch by said box parts renders said feeding mechanism ineffective to feed the box parts and causes said loop forming mechanism to be driven through a loop forming cycle, first power means for vertical movement of said stop element, iirst and second control means for controlling said rstl power means, said first control means being arranged to be actuated by the approach of a box part into said machine and to cause movement of said stop element to said extended position, said second control means l'1'1 being arranged to be actuated during an earlier part of each loop forming cycle of said machine and to cause movement of said stop element to said retracted position, second power means for longitudinal movement of said stop assembly between two positions at which said stop element will respectively actuate said stop switch to stop said wirebound box blanks with the loop forming mechanism at opposite sides of the center of a space between adjacent box parts, 'and third control means for controlling said second power means, said third control means being mounted on said machine in such position as to be engaged and actuated by a relatively movable part therein during a later part of each loop forming cycle of said machine to cause said third power means to move said stop assembly longitudinally to alternate ones of said` two positions on successive cycles,

3. 'In a machine for forming loop fasteners from binding wires interconnecting -a spaced series of wirebound box parts, apparatus for adapting said machine to form loop fasteners of different lengths in successive cycles comprising, a stop assembly mounted in said machine for longitudinal movement, said stoprassembly including a stop element which is transversely Vmovable between an extended position at which it projects into the path of a leading'edge of said boxpparts and a retracted position clear of said path and which is also longitudinally movable by engagement with the moving box parts, a stop switch actuated Yby the longitudinal movement of said stop element, said stop switch being connected to control the work feeding and loop forming mechanisms of said machine, whereby 4actuation of said stop switch by said box parts renders said feeding mechanism ineffective to feed the box parts and causes said loop forming mechanism to be driven through a loop forming cycle, rst electrically controlled power means coupled to said stop element for transverse movement thereof, -a ready switch and a reset switch connected to control said rst power means, 'said ready switch being arranged to be actuated by the approach of a box part into said machine to cause transverse movement of said stop element to said extended position, and said reset switch being arranged to be actuated by a relatively moving part of said machine during each loop forming cycle to cause transverse movement of said stop element to said retracted position, secondelectrically controlled power means for longitudinal movement of said stop assembly between two positions at which said stop element will respectively actuate said stop switch to stop said wirebound box blanks with the loop forming mechanism at opposite sides of the center of a space between adjacent box parts, and a selector switch connected to control said second power means, said selector switch being arranged to be actuated by a relatively moving part of said machine during a later part of each loop forming cycle to -actuate said second powerrneans for longitudinal movement of said stop assembly to alternate positions on successive cycles.

4. In -a machine for forming loop fasteners from binding wires interconnecting a spaced series of wirebound box parts, apparatus for adapting said machine to form loop fasteners of different lengths in successive cycles comprising, Ia pair of stop assemblies mounted in said machine, each of said stop assemblies including a stop element which is longitudinally movable and is also transversely movable between an extended position at which it pro- 55 jects into the path of a leading edge of said box parts and a retracted position clear of said path and a stop switch actuated by the longitudinal movement of said stop element when said stop element is engaged by said leading edge, said stop assemblies being mounted with their respective stop elements positioned to be engaged by said leading edge an actuate said stop switch with the loop forming mechanism at opposite sides of the center of a space between adjacent box parts, said stopy switch being connected to control the work feeding and loop forming mechanisms of said machine, whereby actuation of said stop switch by said box parts renders said feeding mechanism ineffective to feed the box parts and causes said loop forming mechanism to be driven through a loop forming cycle, power means coupled to each of said stop elements for selective movement thereof between said retracted and extended positions, control means connected to control said power means, said control means being arranged for actuation by a moving part of said machine once each cycle of said machine whereby said control means is indexed to cause said power means to move said stop elements alternately into said projected position on successive cycles of said machine.

5. In a machine for forming loop fasteners from binding wires interconnecting a spaced series of wirebound box parts, apparatus for adapting said machine to form loop fasteners of different lengths in successive cycles comprising, a pair of stop assemblies mounted in said machine, each of said stop assemblies including a stop element which is longitudinally movable and is also transversely movable between an extended position at which it projects into the path of a leading edge of said box parts and a retracted position clear of said path and a stop switch actuated by the longitudinal movement of said stop element when said stop element is engaged by said leading edge, said stop assemblies being mounted with their respective stop elements positioned to be engaged by said leading edge and actuate said stop'switch with the loop forming mechanism at opposite sides of the center of a space between adjacent box parts, said stop switch being connected to control the work-feeding and loop forming mechanisms of said machine, whereby actuation of said stop switch by said box parts renders said feeding mechanism ineffective to feed the box parts and causes said loop forming mechanism to be driven through a loop forming cycle, a pair of electrically controlled power means, one coupled to each of said stop elements for movement thereof between said retracted and extended positions, a control circuit for controlling said power means, said circuit including a selector switch arranged to be actuated by a relatively moving part in said machine once during each machine cycle and adapted to connect alternate ones of said power means into said control circuit on successive cycles, a ready switch arranged to be actuated by the approach of a box part into said machine and connected to actuate the power means then in said circuit to move the stop element associated therewith to said extended position, and a reset switch arranged to be actuated by a relatively moving part of said machine during each cycle and connected to actuate the power means then in said circuit to move its stop element to said retracted position.

References Cited in the le of this patent UNITED STATES PATENTS UNTTTD STATES PATENT QFTTCS CE1 'HHCATE F CORRECTION Patent N0 a 2g947329 August 2, 1960 David G'e Kingsley It is herebjr certified that error appears n the-printed specification of' the above numbered patent requiring correction and that the said Letters Patenl'J should read as corrected below.

Signed and sealed this 31st day of January 1961a (SEAL) Attest:

1 ARL HT7 AXLINE ROBERT C. WATSON Attesting Ofcer Commissioner of Patents

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