US3599855A

US3599855A - Box-stitching apparatus

Info

Publication number: US3599855A
Application number: US806817A
Authority: US
Inventors: Edward V Henc
Original assignee: Individual
Current assignee: Individual
Priority date: 1969-03-13
Filing date: 1969-03-13
Publication date: 1971-08-17
Anticipated expiration: 1988-08-17
Also published as: CA917851A; GB1311362A; DE2011668A1; JPS5031517B1

Abstract

Stitching apparatus comprising a main frame, a stitching head assembly mounted on the frame at a stitching station operable to apply stitches to the overlapping portions of sheet material, actuating means operating at a predetermined continuous rate of speed for advancing the sheet material through the stitching station and means for selectively varying the spacing between adjacent stitches.

Description

Waited States Patent Inventor Edward V. Henc 302 Netherlngton Drive, Broomall, Pa. 19008 Appl. No. 806.8 I 7 Filed Mar. 13, 1969 Patented Aug. 17, 1971 BOX-STITCHING APPARATUS 30 Claims, 22 Drawing Figs.

US. Cl 227/7, 227/102 lint. Cl B27f 7/06 Field of Search 227/2, 3,5, 6, 99,100,103,101,102

References Cited UNITED STATES PATENTS Spiller 227/7 2,277,218 3/1942 Flowers et a1 27/3 2,305,418 12/1942 Harred 227/3 2,376,159 5/1945 McCoy 227/102 2,820,223 H1958 Rydberg et al.. 227/7 3,120,664 2/1964 Mott 227/2 X Primary Examiner-Granville Y. Custer, Jr. Attorney-Howson and l-lowson ABSTRACT: Stitching apparatus comprising a main frame, a stitching head assembly mounted on the frame at a stitching station operable to apply stitches to the overlapping portions of sheet material, actuating means operating at a predetermined continuous rate of speed for advancing the sheet material through the stitching station and means for selectively varying the spacing between adjacent stitches.

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BOX-STITCl-IING APPARATUS The present invention relates to improvements in boxstitching apparatus.

Some prior box-stitching apparatus comprise a main frame, a stitching head located at a stitching station operable to apply stitches to the overlapping edges of sheet material and means for advancing the blank through the stitching station. The blank feed means in these prior box stitchers operates on an indexing principle wherein the sheet material is advanced stepwise through the stitching station and the sheet material is brought to rest momentarily when the stitch is applied. More specifically, the feed means included feed rolls which were actuated by a main drive system which usually included an electric brake for intermittently interrupting operation of the feed rolls to lock the drive system and a ratchet-type advancing mechanism for moving the sheet material through the stitching station.

In this type of intermittent feed system the feed rate is extremely limited. Furthermore, it has been found that it is not possible to achieve uniform spacing between adjacent stitches due to the inherent variable slippage in the brake system, the slippage varying with wear, heat-generated, atmospheric conditions and inertia factors. Additionally, it has been found that the meshing teeth in the ratchet-type advancing system do not mesh uniformly and also contribute to nonuniform spacing between stitches. Other disadvantages include the fact that the parts of the drive and brake system wear rapidly and thus require periodic replacement which is costly and results in down time on the machine.

Uniform spacing between adjacent stitches is desirable and in some instances essential. For example, in some box blanks one of the stitch laps or tabs is provided with an opening to receive an insert and the stitches have to be arranged in a predetermined position relative to the opening so they don't block the same. In other cases, the blank includes a tab portion'which extends out to the stitch lap, serving to facilitate opening of the box. Obviously, the tab would not function properly if it were stitched. Thus, stitch location and uniformity is important.

In accordance with the present invention, the stitching apparatus comprises a main frame, a stitching head added on the frame and a stitching station operable to apply stitches to the overlapping portions of sheet material, actuating means operating at a predetermined continuous rate for advancing the sheet material through the stitching station and means for selectively varying the spacing between adjacent stitches. In the illustrated form of the invention, the actuating means includes at least one pull roll having a resilient cover for advancing the sheet material through the stitching station and means for rotating the pull roll at a predetermined continuous angular rate of rotation. By this arrangement, as the stitching head engages the sheet material to clinch a stitch, the torsional deflection of the resilient cover precludes tearing of the sheet material during application of the stitch. Further, by this arrangement the sheet material may be fed at a high rate of speed through the stitching station. Moreover, since the actuating means is continuous, the spacing between adjacent stitches is uniform.

An object of the present invention is to provide a boxstitching apparatus which is of comparatively simplified construction and which is capable of operating at high speeds to stitch the stitch laps of a box blank.

Another object of the present invention is to provide a boxstitching apparatus which provides uniform spacing between adjacent stitches.

Still another object of the present invention is to provide a box-stitching apparatus incorporating novel features of construction and arrangement whereby the spacing between the stitches may be selectively varied and including sensing means whereby the position of the first stitch may be accurately located when the blank is fed through tee apparatus.

A further object of the present invention is to provide the features discussed above and control means whereby the selective positioning and spacing between stitches may be easily accomplished by even an operator having very little skill.

These and other objects of the present invention and various features and details of the operation and construction thereof are hereinafter more fully set forth with reference to the accompanying drawings, wherein;

FIG. 1 is a top plan view of a box-stitching apparatus in accordance with the present invention;

FIG. 2 is a front elevational view of the box-stitching apparatus;

FIG. 2a is a perspective view of a partially folded box blank;

FIG. 3 is an enlarged view taken on lines 3-3 of FIG. 2 with some of the parts broken away so that the internal construction of the apparatus may be seen more clearly;

FIG. 4 is an enlarged sectional view taken on lines 4-4 of FIG. 3;

FIG. 5 is a fragmentary front elevational view with parts broken away to show the construction of the machine more clearly;

FIG. 6 is an enlarged sectional view taken on lines 6-6 of FIG. 5 showing the delivery roll and upper and lower pull rolls;

FIGS. 7, 8 and 9 are enlarged sectional views taken on lines 7-7, 8-8 and 9-9 respectively of FIG. 5;

FIG. 10 is an enlarged fragmentary end view of the takeup bearing assembly shown in FIG. 9; 7

FIG. 11 is an enlarged sectional view showing the stitching station taken on lines 1 1-11 of FIG. 5;

FIGS. 12 and 13 are enlarged sectional views taken on lines 12-12 and 13-13 of FIG. 11, respectively;

FIG. 14 is a fragmentary view showing the stitcher head ram sensing arrangement;

FIG. 15 is a sectional elevation of the drive assembly, taken on line 15-15 of FIG. 2;

FIG. 16 is a plan view of the control panel;

FIG. 17 is a perspective view of the stitcher shoe assembly;

FIG. 18 is a schematic of the various electrical components of the system for operating the box stitcher apparatus;

FIG. 19 is a sectional view through the upper pull roll showing a single directional rotary bearing mounting for the roll in lieu of the keyed connection shown in FIG. 2;

FIG. 20 is a fragmentary side elevational view of a slip clutch mounted on the pull roll drive shaft; and

FIG. 21 is a fragmentary view showing an alternate mounting for the clinching anvil support to permit adjustment thereof relative to the table top.

The apparatus of the present invention is adapted for use in the processing of blanks of corrugated board or like material which, when completely assembled, form boxes. More specifically, the machine is designed to secure with stitches or staples the overlapping stitch laps L and L of a blank B of conventional configuration and arrangement. The blank B as illustrated in FIGS. 2a and 17 is initially in the form of a flat sheet having a plurality of score lines formed therein to define a pair of end panel sections P and side panel sections P the side panel sections and end panel sections being confronting and opposed in the erected box. The blank B also includes side an end pariel flaps F and F respectively, which form the top and bottom closures and slotted openings between adjacent flaps. In preparing these flaps for the machine, the operator folds the blank along the score lines S and S and then feeds the f lded blank into the stitching station of the machine with the upper stitch lap L overlying the lower stitch lap L whereby the laps are secured by the stitches or staples in this relationship. Even though the apparatus of the present invention is illustrated and described in connection with the stitching of box blanks, it is to be understood that the apparatus may be used to stitch or otherwise secure the overlapping portions of other types of sheet material.

Considering now the broad details and arrangement of the box stitcher and with particular reference to FIGS. 1 and 2,

the apparatus includes main frame including a base 12, upstanding spaced apart sidewalls or support members 14, a bridge 16 spanning the side frame support members 14 and a table top 18 spaced below the bridge 16 and coextensive therewith. A stitching head assembly 20 of generally conventional form is mounted on the bridge operable to stitch the overlapping stitch laps of a box blank B in the manner illustrated. The stitching head assembly 20 includes a stitcher head motor M, connected by suitable transmission means including the belt 21 to effect reciprocating actuation of the former and drive assembly 23 which, as is conventional during a typical cycle, cuts a section of wire, forms it into a U-shaped staple and drives the U-shaped staple through the stitch laps of the box blank whereby the staple is closed to form a stitch upon engagement with the clinching anvil support. In the present instance as explained in more detail hereafter, the cycle of operation of the stitcher head assembly is such that it delivers a predetermined number of stitches within a given time cycle. However, it is noted that the number of stitches delivered per time cycle by the stitcher head assembly may be selectively varied, for example by simply varying the output of the adjustable motor M to increase or decrease the number of stitches delivered in a given time cycle.

Feed and delivery means as explained in more detail hereinafter are provided for advancing the blank through the stitching station. In accordance with the present invention, the apparatus includes means for selectively varying the number and spacing of stitches in each cycle of operation in a manner which is relatively simple and easy to control by the operator.

Turning now to the specific construction of the apparatus, and with particular reference to the feed and delivery system for advancing blanks B through the apparatus, this system which is broadly designated by the numeral 30, includes a pair of closely spaced delivery rolls 32 mounted on a delivery roll shaft 36 rotatably journaled between brackets 31 mounted under table 18. The delivery rolls 32 are located forwardly of the stitching station and cooperate with an upper roll 33 rotatably mounted on a bracket 35 pivotally mounted at its inner end to the bridge 16 and biased downwardly by a tension spring 37 to press the stitched blank B against the delivery rolls 32 as illustrated in FIG. 11. Each delivery roll 32 as illustrated comprises a metal core 32a secured to a shaft by means of a key 36 and a resilient annular outer cover 32b. Further, each of the delivery rolls 32 is mounted so that its periphery projects slightly above the table 18 through a slotted opening 38 in the table 18. The delivery roll shaft 36 is connected through a suitable transmission to a motor drive means M and control circuit so that speed of rotation of the delivery rolls 32 may be varied selectively as described in more detail below.

The pull roll system includes a lower pull roll 40 mounted below the table 18 on a shaft 42 which at opposite ends is rotatably journaled in suitable bearing members. ln the present instance the lower pull roll includes an elongated metal core 42a and an elongated sleeve 42b of resilient material, the periphery of which projects slightly above the table top through a slotted opening 48 in the manner illustrated in FIG. 6. The system further includes, in the present instance, a pair of upper pull rolls 50 and 52 mounted on an upper pull roll shaft 54 vertically aligned with the lower pull roll shaft 42. The upper pull rolls also comprise a metal core 50a and an outer cover 50b made ofa resilient material such as rubber of soft to medium hardness. The core of the upper pull rolls 50 and 52 is, in the present instance, keyed to the pull roll shaft 54 to permit axial adjustment of the upper pull rolls along the shaft for selective positioning of the pull rolls in relation to a particular size blank being run on the apparatus. it is noted that the lower pull roll assembly 40 may comprise a series of spaced smaller rolls mounted on a common shaft similar to the upper pull roll assembly.

In lieu of the pull roll system illustrated, the lower pull roll assembly 40 may be eliminated whereby the upper pull roll assembly simply engages the blank material against the table top in which event the top does not have an opening therein. Ad-

ditionally, in lieu of keying the pull rolls to their respective shafts, single directional rotary bearings 55 of the conventional type illustrated in FIG. 19 may be employed. Additionally, a conventional slip clutch assembly 57 having means for adjusting torque may be provided on the upper pull roll shaft whereby the torsional deflection of the upper pull rolls may be selectively increased or decreased when a staple is being clinched at the stitching station. The clutch may be ad- 10 justed to insure proper feed of the sheet material, for example,

if the nip of the pull rolls is not properly set for sheet material of a given thickness, and aids in maintaining uniform stitch spacing and precluding tearing of the sheet material around the area of the stitches during the stitching operation.

In order to maintain proper control of movement of sheet material through the stitching station, the spacing at the nip of the pull rolls has to be set properly for sheet material of a given thickness. This proper setting in the present instance insures the desired amount of torsional deflection of the pull rolls whereby uniformity of stitch spacing is insured. Accordingly, the pull rolls are adjustable relative to one another to prevent skidding if the gap at the nip is too great, or tearing during stitching if the gap is too narrow. In the present instance, the upper pull roll shaft 54 is adjustable and is supported on takeup bearing assemblies 60 as illustrated in FIGS. 2 and 9. Each takeup bearing assembly includes a takeup bearing block 62 within which the shaft 54 is mounted having a slide guide 64 engageable in a trackway 66 formed integrally with the bridge 16 and guided for movement in the trackway by means of gib strips 68. The roll shaft adjustable mounting assembly 60 further includes a jack fastener block which is internally threaded to receive a screw jack shaft fastener 82 which in turn is rotatably journaled in the bearing block 84 and mounts at its inner end a beveled gear 86 which meshes with a mating gear 88 carried by the adjusting rod 90 which projects beyond one end of the side frame member and mounts an adjusting handle 91. By this arrangement, rotation of the handle 97 rotates the adjusting shaft 90 and through the intermeshing gears effects movement of the rolls upwardly or downwardly depending on the rotation of the adjusting handle 91. It is noted that the roll shaft mounting assembly includes a tension spring 94 circumscribing the jack fastener block 80 to provide resilient mounting for the upper pull rolls.

There is provided a common drive or actuator system for the upper and lower pull rolls, the details of which are best illustrated in FIGS. 2 and 15. As illustrated therein the system includes a prime actuator in the form of a drive motor M mounted on a drive motor mounting plate 102 adjacent the base of the frame, a small drive sprocket 104 mounted on the drive shaft of the motor M and a larger drive sprocket 106 connected to the sprocket 104 by a reducer driver chain 108. The sprocket 106 is mounted on a shaft 110 which mounts a smaller driven sprocket 112 which drives a chain 114 for actuating

sprockets

116 and 118 for the upper and lower pull rolls respectively. The drive system further includes a pivotally mounted idler sprocket 120 which has a tors on spring mounted in the hub to tension the chain 114 and permit adjustment of the rolls relative to one another in the manner described above. Note that the particular drive chain a... sprocket arrangement provides for rotation of the upper and lower pull rolls to advance the blank through the machine in the direction indicated in FIG. 3. The low r pull roll assembly may be mounted for freewheeling and, in this case, there is no need for the sprocket 118 and, of course, the chain 114 is not drivingly connected to the lower pull roll in any manner. An alternate drive system is obviously necessary also where the lower pull roll assembly is not used.

The actuator system includes speed control means whereby the angular rate of rotation of the upper and lower pull rolls my be selectively varied. By this arrangement, with the stitching head assembly operating to deliver a fixed number of stitches for a given time cycle, the spacing between adjacent stitches may be selectively varied.

Guide means are provided for feeding the folded blank B through the stitching station with the stitch laps L and L in overlying relation. As best illustrated in FIG. 17, the guide means includes a stitcher guide shoe 130 pivotally mounted on a bracket 132 depending from the bridge 16 adjacent the stitcher head 20. The stitcher guide shoe 130 has an elongated base 136 mounting at one end a pad 138 which overlies the clinching anvil support 140, the pad 138 having a contoured, dished clinching block 139 operable to clinch the stitch as the driver of the stitching head assembly drives the U-shaped staple through the stitch laps of the box blank. The body of the stitching shoe is formed to provide leftand right-hand guide pockets 141 and 143 for the overlapping stitch laps L and L, of the blank.

The clinching anvil support 140 as best illustrated in FIG. 21 is adjustable relative to the table top, this adjustment being made depending on the thickness of the sheet material being stitched. The clinching anvil support 140 is adjustable so that the clinching block is maintained parallel to the table or perpendicular to the plane of the reciprocating driver of the stitching head assembly. The anvil support140 mounts a rack 143 engaging through an opening in the top table and an adjusting member 145 is provided having a worm 147 which drives a worm gear 149, which worm gear shaft in turn mounts a spur gear 151 which meshes with the rack 143. Thus the height of the clinching anvil support 1411 may be adjusted by simply rotating the adjusting member 145.

In the present instance the base 136 of the stitcher guide shoe forms the lower wall of the right-hand guide pocket 143, and as best illustrated in FIG. 17, the base has formed integrally therewith a center leaf 161 which overlies the rear portion of the base 136. The leaf 161 in turn has an upwardly extending flange 165 at its opposite end to secure it to the bracket 132. The center leaf 161 forms the lower wall of the left-hand guide pocket 141, the upper wall being defined by a platelike member 167, secured to the bracket 132 in the manner shown in FIGS. 13 and 17. The stitcher guide shoe assembly further includes a pair of fold guides to aid the operator in positioning the stitch laps in their respective pockets when feeding a blank B to the stitching station. The lower fold guide 175 has its inner edge 177 in the same plane as the center leaf 161 and positioned immediately therebehind. The fold guide 175 has a cutaway portion so that its upper end 179 is of a narrower width than the fold guide 181. The outer terminal end has a turned-up lip portion 183. Fold guide 181 is formed integrally with the upper plate member 167 and projects upwardly at a sharper angle than the fold guide 175. By this arrangement, the operator may guide the stitch laps into the respective pockets in the manner illustrated in FIG. 17. In some instances where it is desired to stitch the overlapping stitch laps reversed to the overlapping relation shown, an alternate guide shoe having reversed pockets is used.

Thus, briefly, in the operation of the box stitcher the operator inserts the forward edge of the blank with the overlapping edges of the blank disposed in respective leftand right-hand pockets of the stitching shoe and as the blank is advanced forwardly in this position into the nip of the upper and lower pull rolls, it is actuated by the pull rolls into and through the stitching station where a plurality of stitches are applied in predetermined sequence by the stitching head to secure the overlapping edges of the blank. A guide roll 33 pivotally mounted on an arm 35 secured to the bridge of the frame is provided to press the blanks into engagement with the delivery roll after it is passed through the stitching station. A tension spring 37 pivots the arm 35 to maintain the roll 33 in contact with the blank during movement through the station. Preferably, the delivery roll assembly 32 is run at a slightly faster angular speed than the pull roll assembly. However, when the sheet material is stitched from its front leading edge to its trailing edge, the delivery and pull rolls are run at the same speed. TI-Iis is necessary to maintain uniform stitching spacing since the blank B is out of the nip of the pull rolls while still being stitched.

In view of the above, it is clear that the present invention provides a relatively simple high-speed stitching operation. The pull rolls which deliver the sheet material, in the present instance box blanks, through the stitching station are actuated at a predetermined, continuous angular rate of rotation whereby the spacing between adjacent stitches delivered by the stitching head are uniform. It is noted that during the clinching of each stitch, the movement of the blank is interrupted instantaneously and that the torsional deflection of the pull rolls prevents ripping the blank during application of the stitch. It has been found that the clinching of a stitch is accomplished in about one-eightieth of a second, and thus in operation the blank appears to move rapidly and continuously through the stitching station. In the present instance the stitching head assembly cycle is maintained constant or fixed, and the spacing between adjacent stitches may be varied by selectively increasing or decreasing the angular rate of rotation of the pull rolls. Stitch spacing may also be varied by maintaining the feed rate of the blanks through the stitching station fixed and varying the cycle or operation of the stitching head as noted previously.

The apparatus further includes side guide elements which are selectively adjustable and are adapted to prevent the blank from cocking during movement through the stitching station. The side guide elements as best illustrated in FIG. 5 comprise a pair of elongated opposed generally L-shaped leftand righthand guide members and 162 respectively, which are flared outwardly as at 160a and 162a adjacent the feed end of the apparatus and are adapted for movement relative to the table top. To this end the

side guide members

160 and 162 are mounted on

supports

163 and 164 having a collar portion 16% and 162b which circumscribe a pair of guide shafts 176 extending between the sides of the apparatus. The side

guide support members

163 and 164 also include internally threaded collars 160s and 162a which ride and mesh on actuating

shafts

182 and 183. The actuating shafts are mounted in

journals

185 and 187 supported in opposed sidewalls of the apparatus and at their inner terminal ends are connected by means of a clutch to a common transmission 190 connected to a motor M By this arrangement, when it is desired to move the guide brackets relative to one another to increase the spacing therebetween to accommodate a blank of larger width, the motor M,,. which is a reversible motor, is simply actuated to rotate the

shafts

182 and 183 in one direction and the motor is simply reversed to bring the guide brackets closer together for a blank of smaller width.

Another feature of the present invention is the provision of sensing means in the table top for sensing the position of the lead edge of the blank B, and includes means for initiating actuation of the stitching head at a predetermined time interval after the lead edge has passed the sensing point whereby the position of the first stitch relative to the front edge of the blank may be selectively controlled and varied. This sensing element is in the form of a photoelectric edge detector 191 of the reflection type including a light uource 193 in the table top which directs light upwardly against a reflector 19. positioned above the feed path, the light when being reflected downwardly to a photocell 197 below the feed path. The signal produced by interrupting the light source by presence cf the blank B actuates a time delay timer 240 which in turn actuates the stitching head in a manner described in more detail hereafter.

Note that the edge detector 191 is located slightly behind a plane through the point of application of the stitches to the blank, as clearly shown, for example, in FIG. 3.

FIG. 18 illustrates one connection for the various electrical elements of the system which will provide the desired operation, although it will be understood that quite different electrical arrangements may be employed to provide the same features of operation or to provide more or fewer features, depending upon the particular application. As exemplified in FIG. 18, an alternating current power source 10, such as an ordinary 60-cycle power line, is connected across the two AC supply lines 212 and 216 to supply operating power for the entire apparatus. A conventional protective fuse 218 and a main power switch 220 are provided in series in supply line 212 to protect the entire system against overload and to enable turning on and E of the entire electrical system. A power on" pilot light 221 is connected between the supply lines 212 and 216 beyond the power switch 220 so that illumination of pilot light 222 indicates closure of main power switch 220.

The stitcher control system 228 comprises two manually operable switches, namely the photocell power switch 230 and the stitcher power switch 232. Photocell power 230 can be manually closed to supply operating power to photoelectric edge detector 191, to photoelectric relay circuit 238 and to manually settable automatically resetting time delay timer 240. A photocell on pilot light 244 is connected so as to be turned on whenever switch 230 is closed.

Closing of stitcher power switch 232 supplies operating power to the stitcher head control circuit 260, the stitcher head motor M the stitcher head solenoid clutch 264, the stitch sensor 266 and the manually settable stitch counter 268 as required to operate the particular circuitry included in each of these components. A stitcher on" pilot light 270 is connected so as to be turned on whenever the stitcher power switch 232 is closed.

Closing of stitcher power switch 232 causes the stitcher head motor M to operate continuously. However, the stitcher head former and driver assembly or ram 23 is driven by the stitcher head motor through the stitcher head solenoid clutch 264, and is therefore operated only when the latter clutch is energized by the stitcher head control circuit 260. The stitcher head control circuit 260 energizes the solenoid clutch 264 at a time beginning with the occurrence of an output pulse from time delay timer 240, and deenergizes solenoid clutch 264 to stop operation of the stitcher head ram 23 after the ram has performed a predetermined number of reciprocations and has produced a corresponding number of stitches. To provide such disengagement of clutch 264 after a predetermined number of stitches, the stitch sensor 266 is associated with the stitcher head ram 23 so as to produce an electrical impulse for each reciprocatory cycle of ram 23. (See FIGS. 11 and 14.) Many suitable types of stitch sensors will occur to one skilled in the art, including those utilizing moving electrical contacts, capacitance-type proximity-sensing devices, and magnetic proximity-sensing devices such as are preferred for the present example. As described previously, the magnetic proximitysensing device 266 is positioned adjacent an upper end of ram 274 so that the magnetic field of the sensing device is disturbed once during each cycle of the ram to produce an output electrical pulse for each stitch. The latter pulses are supplied to the manually settable stitch counter 268, which may be a conventional commercially available counter which can be manually set to count the electrical impulses supplied thereto and to produce an output signal when a predetermined number of such pulses have been counted. The latter output signal is supplied to stitcher head control circuit 260 to cause deenergization of solenoid clutch 264 and resultant termination of the stitching operation. The stitcher control system therefore operates overall to start the application of stitches when a pulse is received from time delay timer 240, to produce a series of regularly time-spaced stitches equal to the number previously set on the stitch counter 268, and then to stop the stitching operation until the next pulse is received from time delay timer 240.

The time at which the stitch-starting pulse from time delay timer 240 occurs is delayed by a manually settable amount with respect to the time at which the leading edge of the box blank reaches the stitching position. To accomplish this, the photoelectric edge detector 191 is positioned so as to produce an output pulse each time the leading edge of a box blank reaches the position of the edge detector. There are many types of devices known, and commercially available in the art, which may be used for this purpose. In the present example, it is assumed that the photoelectric edge detector is of the reflection type in which a light source below the feed path for box blanks directs light upwardly against a reflector positioned above the feed path, the light then being reflected downwardly again to a photocell beneath the feed path. In the absence of the box blank, the photocell is strongly illuminated by the reflected light, but as soon as the leading edge of the box reaches the photocell position, the photocell is shielded from light by the box blank and its output voltage changes abruptly, thereby providing a signal indicative of the arrival of the leading edge of the box at the photocell position.

This signal is amplified, shaped and otherwise processed in a photoelectric relay circuit 238 so as to produce an output pulse suitable for actuating the time delay timer 240. Both the photoelectric relay circuit 238 and the time delay timer 240 may be conventional and commercially available apparatus. Time delay timer 240 is preferably of the type which responds to an input pulse to produce an output pulse only after a time delay of a duration determined by the manual setting of the timer. Accordingly, the output pulse from time delay timer 240 which initiates stitching occurs at a time delayed, with respect to the time at which the leading edge of the box reaches the photocell, by an amount which is fixed for any given setting of the timer, but which may be changed by manual adjustment of the timer to control the distance from the leading edge of the box blank at which the first stitch occurs.

The portions of the electrical circuitry thus far described will therefore enable the operator to select the setback of the first stitch from the leading edge, for any given feed speed of the box, and also to select the number of stitches applied to a given blank by manual setting of the stitch counter 268. Control of the feed speed of the box blank is also provided, thereby enabling the operator to control the distance between successive stitches on the box blank, as will now be described.

Operation of the feed or pull rolls and the delivery roll is controlled by the stop-run" manually operable switch 280, which, when open, cuts off operating power to both drive motors and, when closed, supplies both motors with the power required for their operation at controlled rates. Thus the feed roll motor M which may be a conventional AC or DC motor, is supplied with operating power through the feed roll motor drive and speed control circuits 284, to which there is connected the feed roll speed control 286 which is adjustable from a minimum to a maximum speed position. The feed roll motor M the drive and speed control circuits 284 and the speed control 286 therefor may all be entirely conventional and thus need not be described in detail.

Similarly, a conventional delivery roll motor M is driven and controlled through delivery roll motor drive and speed control circuits 292, its speed being manually controllable by means of delivery roll speed control 294, which again may be adjustable between a minimum and a maximum speed position. These elements of the delivery roll motor system may also be entirely conventional in orm and hence need not be described or shown in detail. Ordinarily, the delivery roll motor speed will be sufficient to operate the delivery rolls at a higher rate than the feed rolls, so as to provide the desired rapid removal of each box blank from the apparatus aft r its stitching has been completed.

As mentioned previously, the side guides for guiding the edges of the box blank as it comes through the stitching machine are laterally adjustable by means of a motor drive under the control of the operator. FIG. 18 shows one appropriate electrical arrangement providing this desired operation. The side guide motor M, is appropriately coupled mechanically through any suitable gear arrangement 302 to a left-guide solenoid clutch 304 and to a right-guide solenoid clutch 306. Whether the left guide or the right guide is operated thendepends upon whether solenoid clutch 304 or solenoid clutch 306 is actuated by the electrical circuitry, and the direction of operation of the side guide motor M is also determined by the electrical circuitry shown.

' More particularly, the left-guide solenoid clutch 304 is connected between AC supply line 216 and AC supply line 212 by way of left-guide out switch 310 and left-guide in switch 312 in parallel with each other. Each of the latter switches is of the double-pole single-throw momentary contact pushbutton type, the contacts thereof being normally open. Accordingly, left-guide solenoid clutch 304 is normally disconnected from the AC supply lines by the normally

open switches

310 and 312, but is connected to the power rails, and thereby energized, whenever the operator operates either of the pushbutton switches 310 and 312 to close either of the corresponding pairs of

switch contacts

314 or 316. Similarly, right-guide solenoid clutch 306 is normally disconnectedfrom the AC supply lines by the right-guide out switch 320 and the right-guide in switch 322 in parallel with each other;

switches

320 and 322 may be identical to each other and to switches 3110 and 312, and operation of either of

switches

320 and 322 by the operator will actuate right-guide solenoid clutch 306 to cause movement of the right guide.

Tl-le direction in which a side guide is moved is determined by the motor-reversing circuit 326 and the condition of the lower pairs of contacts in each of the

switches

310, 312, 320 and 322. Thus if either the left-guide out switch 310 or the right-guide in" switch 322 is operated, AC supply line 212 is thereby connected to input terminal 332 of the motorreversing circuit 326; conversely, if either the left-guide in switch 312 or the right-guide out switch 320 is operated, supply line 212 is connected to input terminal 334 of motorreversing circuit 326. Motor-reversing circuit 326 may be of any conventional form such as to operate the side guides motor in one direction of rotation when AC line power is supplied to input terminal 332 of the reversing circuit, and to drive the motor in the opposite direction when AC line power is applied to the other input terminal 334 of the reversing circuit. It will be appreciated that since the drive arrangement for the side guides in this example is of the lead screw type using common lead screw for both guides, the in motion of the right guide is in the same direction as the out motion of the left guide and is produced by the same direction of motor rotation, and conversely for the opposite direction of motion of the guides.

Accordingly, an operator can provide inward or outward motion of the left or the right guide, at will, by depressing the appropriately labeled one of the

switches

310, 312, 320 and 322 for so long as motion of the corresponding guide is desired. It will be understood that while the circuit shown is effective for this purpose and is of relative simplicity, more complicated circuitry may be provided toaccomplish other features and ends. For example, other additional arrangements of ganged switches may be utilized so that operation of any one of the control switches will prevent operation of the others, thereby avoiding difficulties which might occur if an operator were to operate more than one switch simultaneously. However, such additional apparatus is not required for operation in accordance with the invention.

In the overall operation of the system then, the operator sets the feed motor roll speed control 286, the delivery roll speed control 294, the time delay timer 240 and the stitch counter 268 to the settings suitable for the particular stitching operation to be performed. In production, an unskilled operator need only be provided with data indicating the dial settings for these four controls, which have been determined previously either by calculation, by previous experience with the same type of job order, or by experiments on a few samples of the particular type of box to be stitched. As pointed out above, adjustment of the feed roller motor speed, while keeping all other adjustments constant, will change the distance between stitches and the amount of setback of the first stitch from the leading edge; adjustment of the time delay timer 240, other controls being fixed, will adjust the amount of setback of the first stitch from the leading edge of the box; and adjustment of the stitch counter 268 selects the number of stitches applied. Additionally, as noted above, the distance between adjacent stitches may also be varied by selective adjustment of the stitching head assembly motor M to effect a greater or lesser number of stitches delivered for a given time cycle. Adjustment of the delivery roll speed does not control the stitch arrangement, and is merely provided to enable fastest and most reliable discharge of the boxes from the stitching area.

The folded box blank to be stitched is placed between the left and right guides and the appropriate guide control switches are depressed one at a time by the operator to move the guides into relatively close alignment with the opposite edges of the box material. The power switches 220, 230 and 232 are then turned on and the corresponding operation of the pilot lights observed. After a suitable war-mup time of a few seconds, the box blanks are then fed into the feed rolls and the desired automatic feed through and stitching of the blanks occurs as described above.

In view of the above, it is readily apparent that the present invention provides a novel box-stitching apparatus which is of extremely simplified design and is capable of extremely highspeed stitching. The disadvantages of prior apparatus employing the intermittent feed principle are overcome by the present continuous feed arrangement wherein the spacing between stitches may be maintained uniform for a plurality of blanks processed and wherein the location of the stitches may be accurately positioned. More specifically, the operation and construction of the pull rolls incorporating the torsional deflection facilitates high-speed stitching with uniformity and without damage to the blank. Moreover, the means for varying the spacing between stitches by increasing the angular rate of rotation of the pull rolls, the means for varying the position of the lead stitch relative to the blank, and the means for adjusting the number of stitches applied in each cycle of operation are extremely simplified so that even an operator having very little skill can run the apparatus effectively.

I claim:

l. Stitching apparatus comprising a main frame, a stitching head assembly mounted on the frame at a stitching station operable to apply stitches to the overlapping portions of sheet material during a stitching cycle, actuating means for advancing the sheet material through the stitching station, said actuating means being in continuous engagement with the sheet material during the stitching cycle and including torsionally deflectable means to permit the sheet material to pause momentarily during application of a stitch to the sheet material.

2. Stitching apparatus as claimed in claim 1 wherein said actuating means includes at least one pull roll mounted on a pull roll shaft and including means for selectively varying the angular rate of rotation of said pull roll shaft whereby the spacing between adjacent stitches may be selectively varied.

3. Stitching apparatus as claimed in claim 1 including upper and lower pull rolls mounted on upper and lower pull roll shafts respectively, and means for angularly rotating at least one of said pull roll shafts wherein sheet material is advanced through the nip of the upper and lower pull rolls.

4. Stitching apparatus as claimed in claim 3 wherein each of said pull rolls comprise a core and a cover made of a resilient material adapted to engage the sheet material.

5. Stitching apparatus as claimed in claim 1 including sensing means at the stitching station operable to effect actsation of the stitching of head when the sheet material has reached a predetermined position at the stitching station as sensed by said sensing means.

6. Stitching apparatus as claimed in claim 3 including a common drive means for actuating said upper and lower pull rolls.

7. Stitching apparatus as claimed in claim 6 wherein said drive means includes a motor, a sprocket carried by each of said pull roll shafts and transmission means connecting said sprockets to said motor in a manner to effect rotation of said pull rolls in opposite directions.

8. Stitching apparatus as claimed in claim 3 wherein said pull rolls are located rearwardly of said stitching head as sembly and including at least one delivery roll mounted forwardly of said switching head assembly and including delivery drive means for actuating said delivery roll.

9. Stitching apparatus as claimed in claim 8 including control means for said delivery drive means whereby the rate of rotation of the delivery roll may be selectively varied in relation to the rate of rotation of said pull rolls.

10. Stitching apparatus as claimed in claim wherein said frame includes a table top and wherein said sensing means comprises a photoelectric detector of the reflection type including a light source in the tabletop, a reflector positioned above the tabletop and a photocell below the path of the sheet material operatively connected to the stitching head assembly.

11. Stitching apparatus as claimed in claim 10 including a time delay timer operable to receive a signal from said photocell and delay actuation of said stitching head assembly a predetermined time period after receiving said signal.

12. Stitching apparatus as claimed in claim 1 wherein said stitching head assembly includes a stitcher head motor, a former and drive assembly and transmission means connecting said motor to said former and drive assembly to effect reciprocating movement of said former and drive assembly to deliver stitches to the sheet material.

13. Stitching apparatus as claimed in claim 12 including means for sensing the number of reciprocations of the former and drive assembly during the stitching cycle and including means for deactivating reciprocating movement of said former and drive assembly after a predetermined number of stitches.

l4. Stitching apparatus as claimed in claim 3 including means for selectively adjusting the gap between the confronting peripheral surfaces of the pull rolls.

l5. Stitching apparatus as claimed in claim 1 wherein said frame includes a tabletop and including a pair of side guides which are selectively adjustable relative to one another depending on the size of the sheet material being processed.

16. Stitching apparatus as claimed in claim 15 wherein said means for selectively adjusting the spacing between the side guides includes a motor actuator, a common transmission, a threaded rotary shaft for each of said side guides connected to said transmission by means of a clutch.

17. A method of stitching the overlapping portions of sheet material consisting of the steps of advancing sheet material through a stitching station by means of rotating actuator means operating at a predetermined continuous rate of speed, stitching the overlapping portions of the sheet material as it is advanced through the stitching station and continuously engaging the sheet material as it passes through the stitching station by torsionally deflectable means to permit the sheet material to pause momentarily during application of a stitch to the sheet material.

18. Stitching apparatus for applying stitches to the overlapping portions of sheet material comprising a main frame, a stitching head assembly mounted on the main frame at a stitching station operable to apply stitches to the overlapping portions of sheet material, means for advancing sheet material through the stitching station and guide means for guiding the folded blank through the stitching station with the stitch laps in overlying relation including a stitcher guide shoe pivotally mounted on a bracket of the main frame.

19. Stitching apparatus as claimed in claim 18 wherein the guide shoe consists of an elongated base mounting at one end a pad overlying the clinching anvil support, said pad having a contoured clinching block, said guide shoe being formed to provide leftand right-hand guide pockets for the overlapping stitch laps.

20. Stitching apparatus as claimed in claim 19 wherein the base of the stitcher guide shoe forms the lower wall of one of the guide pockets and herein the shoe includes a center leaf overlying the base forming the lower wall of the other guide pocket and a pair of fold guides to aid the operator in positioning the stitch laps in their respective pockets.

21. Stitching apparatus as claimed in claim 18 including a pair of side guide elements which are selectively adjustable in a widthwise direction and serve to position the blank for proger movement through the stitching station.

2 Stitching apparatus comprising a main frame, a stitching head assembly mounted on the frame at a stitching station operable to apply stitches to the overlapping portions of sheet material, actuating means for advancing the sheet material through the stitching station, said actuating means including at least one pull roll having a resilient cover continuously engaging the sheet material and being torsionally deflected thereby to permit said sheet material to pause momentarily during application of a stitch to the sheet material.

23. Stitching apparatus comprising a main frame, a stitching head assembly mounted on the frame at a stitching station operable to apply stitches to the overlapping portions of sheet material, actuating means for advancing the sheet material through the stitching station, said actuating means including torsionally deflectable means in continuous engagement with the sheet material during passage thereof through the stitching station and operable to permit the sheet material to pause momentarily during application of a stitch to the sheet material.

24. Stitching apparatus comprising a main frame, a stitching head assembly mounted on the frame at a stitching station operable to apply stitches to the overlapping portions of sheet material during a stitching cycle actuating means for advancing the sheet material through the stitching station, said actuating means including continuously operating mean in continuous engagement with the sheet material during the stitching cycle and torsionally deflectable thereby to permit the sheet material to pause momentarily during application of a stitch to the sheet material.

25. Stitching apparatus comprising a main frame, a stitching head assembly mounted on the frame at a stitching station operable to apply stitches to the overlapping portions of sheet material, actuating means continuously operating at a predetermined rate of speed for advancing the sheet material through the stitching station, said actuating means including at least one pull roll having a resilient cover engaging the sheet material and being torsionally deflectable thereby to permit the sheet material to pause momentarily during application of a stitch to the sheet material and means for selectively varying the spacing between adjacent stitches.

26. Stitching apparatus comprising a main frame, a stitching head assembly mounted in a fixed position on the frame at a stitching station operable to apply stitches to the overlapping portions of sheet material, a pull roll shaft, actuating means for continuously rotating the pull roll shaft during a stitching cycle, at least one pull roll having a resilient cover mounted on said pull roll shaft, said resilient cover continuously engaging the sheet material during the stitching cycle and being torsionally deflected thereby to permit said sheet material to pause momentarily during application of each stitch to the sheet material during the stitching cycle.

27. Stitching apparatus as claimed in claim 26 wherein said actuating means includes at least one pull roll mounted on a pull roll shaft and including means for selectively varying the angular rate of rotation of said pull roll shaft whereby the spacing between adjacent stitches ay be selectively varied.

28. Stitching apparatus as claimed in claim 6 including sensing means at the stitching station operable to effect actuation of the stitching head when the sheet material has reached a predetermined position at the stitching station as sensed 1y said sensing means.

29. Stitching apparatus as claimed in claim 23 wherein said frame includes a tabletop and wherein said sensing means comprises a photoelectric detector of the reflection type including a light source in the tabletop, a reflector positioned above the tabletop and a photocell below the path of the sheet material operatively connected to the stitching head assembly.

30. Stitching apparatus as claimed in claim 29 including a time delay timer operable to receive a signal from said photocell and delay actuation of said stitching head assembly a predetennined time period after receiving said signal.

Claims

1. Stitching apparatus comprising a main frame, a stitching head assembly mounted on the frame at a stitching station operable to apply stitches to the overlapping portions of sheet material during a stitching cycle, actuating means for advancing the sheet material through the stitching station, said actuating means being in continuous engagement with the sheet material during the stitching cycle and including torsionally deflectable means to permit the sheet material to pause momentarily during application of a stitch to the sheet material.

5. Stitching apparatus as claimed in claim 1 including sensing means at the stitching station operable to effect actuation of the stitching of head when the sheet material has reached a predetermined position at the stitching station as sensed by said sensing means.

8. Stitching apparatus as claimed in claim 3 wherein said pull rolls are located rearwardly of said stitching head assembly and incLuding at least one delivery roll mounted forwardly of said switching head assembly and including delivery drive means for actuating said delivery roll.

10. Stitching apparatus as claimed in claim 5 wherein said frame includes a table top and wherein said sensing means comprises a photoelectric detector of the reflection type including a light source in the tabletop, a reflector positioned above the tabletop and a photocell below the path of the sheet material operatively connected to the stitching head assembly.

14. Stitching apparatus as claimed in claim 3 including means for selectively adjusting the gap between the confronting peripheral surfaces of the pull rolls.

15. Stitching apparatus as claimed in claim 1 wherein said frame includes a tabletop and including a pair of side guides which are selectively adjustable relative to one another depending on the size of the sheet material being processed.

19. Stitching apparatus as claimed in claim 18 wherein the guide shoe consists of an elongated base mounting at one end a pad overlying the clinching anvil support, said pad having a contoured clinching block, said guide shoe being formed to provide left- and right-hand guide pockets for the overlapping stitch laps.

21. Stitching apparatus as claimed in claim 18 including a pair of side guide elements which are selectively adjustable in a widthwise direction and serve to position the blank for proper movement through the stitching station.

22. Stitching apparatus comprising a main frame, a stitching head assembly mounted on the frame at a stitching station operable to apply stitches to the overlapping portions of sheet material, actuating means for advancing the sheet material through the stitching station, said actuating means including at least one pull roll having a resilient cover continuously engaging the sheet material and being torsionally deflected thereby to permit said sheet material to pause momentarily during application of a stitch to the sheet material.

27. Stitching apparatus as claimed in claim 26 wherein said actuating means includes at least one pull roll mounted on a pull roll shaft and including means for selectively varying the angular rate of rotation of said pull roll shaft whereby the spacing between adjacent stitches may be selectively varied.

28. Stitching apparatus as claimed in claim 26 including sensing means at the stitching station operable to effect actuation of the stitching head when the sheet material has reached a predetermined position at the stitching station as sensed by said sensing means.

29. Stitching apparatus as claimed in claim 28 wherein said frame includes a tabletop and wherein said sensing means comprises a photoelectric detector of the reflection tYpe including a light source in the tabletop, a reflector positioned above the tabletop and a photocell below the path of the sheet material operatively connected to the stitching head assembly.

30. Stitching apparatus as claimed in claim 29 including a time delay timer operable to receive a signal from said photocell and delay actuation of said stitching head assembly a predetermined time period after receiving said signal.