US2718260A - Die-cutting press with automatically variable travel of work table - Google Patents

Description

Sept. 20, 1955 s. F. oAKEs DIE-CUTTING PREss WITH AUTOMATICALLY v VARIABLE TRAVEL 0E WORK TABLE V5 Sheets-Sheet l Filed Aug. V14, 1951 Y AlNvlaNTo-R. STEWART "F, j `KES- s. F. oAKEs D1ECUTTING PRESS WITH AUTOMATICALLY Sept. 20, 1955 VARIABLE TRAVEL OF.' WORK TABLE 5 Sheets-Sheet 2 Filed Aug. 14, 1951 Sept. 20, 1955 4 s. F. oAKEs VARIABLE TRAVEL OF WORK `Filed Aug. 14, 1951 DIE-CUTTING PRESS WITH AUTOMATICALLY TABLE v v 5 Sheets-Sheet 5 STEWART F. QKES ATTORNEY sept. 2o, 1955 Filed Aug. 14, 1951 feo S. F. OAKES 5 Sheets-Sheet 4 TAB E MOTOR HEAD oul oN .los I. '22 Quill; Q 79 '\\|22q \-|2|a') cYcLE MoQR' 86 `|02 AuTo. Ho. ST RT 85 i-E188 MorsTAnT l |030 i I H9 MoTsToP 8B L f 87 Mi .seb .m |20 as 8T MASTER AuTo. MOTOR E r S'roos J0@ CONT. STOP T o `B4 90 9|\ (hdi P /j-'Ym MSER cYcLE START |02 05 l u A 89 /loe com. :GL/|05 |55b |35 135e los E V43 can |04 9 40a TD v nza Ls-4 83 :oec l STEWART F. OAKES ATTOR NLY Sept. 20, 1955 s.-F. oAKl-:s f v 2,718,260

DIE-CUTTING PRESS WITH AUTOMATICALLY VARIABLE TRAVEL. OF' WORK TABLE Filed Aug. 14, 1951 5 Sheets-Sheet. 5

open W Ls |{c,osed

W D TD l n running P 22\ lh HEAD MoToR TABLE A m 2' Joe ou ouT ,89a cycle start-die breaks beam G G G MoToR' cYcLE cYcLE @W LS., START START 77 YT, {closed C) no dAu-ro. Q

STOP ooNT. AuTo.sToP

l b -al Q d m C) beam reestablshed head starts down *7%. l2. {table stops A l,LS-2 closes Izq' /0 'Ff die cuts Y 'q' head starts up-table starts out b C d e F ||5 5045A- Tw M TD4 TJ -2 TD-I lTD-smnnmg l] A I 80" L k i '9 =1^=. yq/4 head moving up-table movlng out 992-7 99bIDBa I Ill@ ' V TD3 runs out Q-zl IE7?. l5. head up-table stops mvENToR STEWART F. OAKES ATTORN EY United States Patent O DIE-CUTTIN G PRESS WITH AUTOMATICALLY VARIABLE TRAVEL F WORK TABLE Stewart F. Oakes, Whitinsville, Mass., assignor to Hobbs Manufacturing Company, Worcester, Mass., a corporanon of Massachusetts Application August 14, 1951, Serial No. 241,713

44 Claims. (Cl. 164-21) The present invention relates to power-driven presses of .the type that are employed for the performance of various blanking operations, in which a downwardly movlng head is employed to repeatedly force a cutting die, after each manual repositioning of same, through a stack of sheet material supported on a table. Such presses are widely used in the manufacture of identical blanks that are die cut from stacked sheet material, as for example in the manufacture of envelope blanks and other paper products, or in the manufacture of garments and other articles from sheets of textile or other material.

In prior presses of this type, the work supporting table, when power-actuated, has a fixed or constant length of travel. This makes it necessary, in the operation of presses of this type, for the stack of sheets, during its conversion into a plurality of stacks of blanks, to be manually shifted, frequently and with great care, on the table, in order that the die (whose position on the work is changed after each cutting operation) may come to rest, for the next cutting operation, in a position fully under the head, for the die is apt to be broken or damaged if it is only partially under the head.

My invention provides a die-cutting press having a power-drlven work table whose length of travel, for each cutting operation, is automatically determined, in each and every case, by the longitudinal position of the die on the table. Thus said die, whatever its position on the work, will always come to rest, squarely beneath the head, for each cutting operation. My invention provides an automatic control mechanism which is adapted to govern the movements of both the work-supporting cuttmg board or table, and the pressing head, so that 1n any position of the die on the work, a complete cycle of operations is performed in response to initiation of the inward movement of the work-carrying table. Furthermore, at the end of each operating cycle, the cutting table is returned automatically to starting position, so

that the operator can conveniently and safely relocate the die for another cut. The press is then ready for the performance of another operating cycle, in which the length of table travel is again controlled in accord-A ance with the new location of the die, without requiring any further effort on the part of the operator', other than pushing the control switch button which starts the operating cycle.

The above and other advantageous features of the present invention will hereinafter more fully appear from the following description, considered in connection with the accompanying drawings, in which,

Fig. 1 is a view in side elevation of a die-cutting press embodying the present invention.

Fig. 2 is a plan view of the press shown in Fig. 1.

Fig. 3 is a view in end elevation of the press shown in Fig. l, as viewed from the left.

Fig. 4 is a View in end elevation of the press shown in Fig. 1, as viewed from the right.

Fig. 5 is a fragmentary sectional view along the line Mice 5-5 of Fig. l on an enlarged scale, and illustrating the construction of the head drive.

Fig. 6 is a fragmentary sectional view along the line 66 of Fig. 3 on an enlarged scale, and illustrating the construction of the table drive.

Fig. 7 is a detail sectional view along the line 7 7 of Fig. 6, looking in the direction of the arrows.

Fig. 8 is a schematic wiring diagram illustrating the arrangement of the electrical devices for controlling the driving mechanisms of the table and head, respectively.

Fig. 9 is a schematic wiring diagram of the control panel.

Fig. 10 is a view in front elevation of the control panel.

Figs. ll to l5, inclusive, are diagrams illustrating the relative positions occupied by the table and head during the performance of each operating cycle under the control of the electrical devices shown in Fig. 8.

Fig. 16 is a fragmentary view showing a detail of the table drive.

i Fig. 17 is a schematic layout of each of the several relays shown in Fig. 8.

Referring rst to Figs. 1, 2 and 3, the present invention is shown for purposes of illustration as being embodied in a vertical press having a pair of spaced upright frame members 1, providing guide ways 2 for supporting a head 3 between slides 4. The head 3 is adapted to be moved up and down between the guide ways 2 by means of connecting rods 5 secured to the ends of a cross shaft 6 extending through the head 3.

The connecting rods 5 are driven in unison from crank pins 7 mounted at the ends of a crank shaft 8 extending between the frame members 1, with one end of the shaft 8 providing a driving gear 9. As best shown in Fig. 4, the gear 9 is driven by a pinion 10 on a stub shaft 11 which extends through one frame member 1 and carries a gear 12 in mesh with a pinion 13 mounted on a shaft 14 extending through a ily wheel 15. An electric motor 16 serves to drive the fly wheel 15 through a belt 17 and pulleys 18 and the shaft 14 is adapted to be connected to the fly wheel 15, at intervals, under the control of a magnetic clutch 19 and a magnetic brake 20, the construction and functions of which will be hereinafter described in detail, with reference to Fig. 5.

The press also comprises a fixed bed 21 extending between the frame members 1, the function of the bed 21 being to provide a rigid support for the work that is to be operated upon by downward movement of the head 3. For the purpose of carrying the work for operation upon by the head 3, a cutting table 22 is provided, which as best shown in Fig. 1 is movable on rollers 23 mounted on a cradle 24 projecting forwardly from one side of the bed 21. The cradle 24 constitutes an extension of the bed 21 on which the cutting table 22 may be moved freely back and forth for the purpose of receiving the work and moving it over the bed 21 to be operated upon by the head 3.

As best shown in Fig. 3, the work W is shown for purposes of illustration as consisting of a stack of sheets of paper which are supported to at condition by the cutting table 22, whose repeated inward movements, from a rest or retracted position such as shown in Figs. 1, 2, 6 and 11, dispose the work W beneath the head 3, each time with a die D (here shown of conventional envelope blank shape) placed by the operator in a different position on the stack of sheets, so that the latter is ultimately converted, by a succession of press operations, into a plurality of stacks of envelope blanks. As will be hereinafter set forth, in detail, the functioning of the automatic control for the parts of the press is such that when once the die D has been placed in position on the work, with the table 22 supported on the cradle 24 be- A yond the bed 21, all that is required of the operator is to push the button of a starting switch, whereupon the table 22 will be moved into a predetermined position on the bed 21, followed by downward movement of the head 3 to engage the die D. After each die-cutting operation, the raising of the head and the automatic withdrawal of the cutting table 22 to a predetermined position completes the operating cycle.

The need for such automatic controls as referred to above should be at once apparent from a consideration of the drawings; from Fig. 3 it can be observed that the transverse dimensions of the head 3 and work material W are nearly the same, with that of the head being slightly greater; looking at Figs. 11 to l5, however, it should be noted that the longitudinal dimension of the work material is considerably greater than that of the head. Therefore, if the table were moved towards the head a fixed distance on each cutting operation, there would be no assurance that the die would be properly positioned beneath the head. By means of the instant invention it is possible to employ a head having a smaller contacting surface than the work material upon which it operates, and yet, by a system of automatic controls as set forth hereinafter, the proper cutting relationship between the die and the head for each cutting operation will always be assured.

As previously pointed out, the table 22 is movable freely with respect to the bed 21, due to its support by the rollers 23 of the cradle 24. For the purpose of controlling such movement of the table 22, its outer end provides a driving pin 25 which extends downwardly into a slot 26 provided between a pair of spaced vertical plates 27 which extend beyond the cradle 24 and serve to support the inner ends of the shafts 28 on which the rollers 23 are mounted, see Fig. 3. The lower end of` the pin 2,5 is, therefore, free to move back and forth in the slot 26 between the plates 27 which also serve to support between them a mechanism for imparting a reciprocatory movement to the cutting table 22 by driving the pin 25 first in one direction and then in the other.

As best shown in Fig. 6, the lower end of the pin 25 is connected to a slide 29 that is mounted on tracks 29a for horizontal movement between the plates 27. The slide 29 is provided with a pair of downwardly extending dogs 30 that are adapted to receive between them a drive block 31 mounted between the links of a pair of spaced chains 32 which extend beneath the table 22. The chains 32 pass around sprockets 33 mounted on shafts 34 supported between the plates 27, and one shaft 34 extends through one plate 27 and is provided at its end with a driving pulley 35. This pulley 35 is connected by a belt 36 to a second pulley 37 forming part of a transmission 38 mounted on a base B projecting from one of the side plates 27, see Fig. 3.

The transmission 38 includes a shaft 39 on which the pulley 37 is mounted and suitable gearing 40 by means of which the shaft 39 may be selectively driven in opposite directions by electric motors 41 and 42. The motors 41 and 42 are mounted on the base B on opposite sides of the transmission 38, and the shafts 43 and 44 of the motors are adapted to be connected to shafts 45 and 46, respectively, forming part of the transmission 38 through magnetic clutches 47 and 48. By controlling the energization of the magnetic clutches 47 and 48, in the manner hereinafter described, it is possible to drive shaft 39 carrying the pulley 37, in one direction or the other to thereby determine the direction in which the chains 32 are driven with relation to the slide 29, which as previously pointed out is connected to the cutting table 22 by the pin 25. The transmission 38 also provides a magnetic brake 49 (see Figs. 3 and l6) cooperating with the pulley shaft 39, so that the table 22 .can be quickly and positively brought to rest,

4 after movement in either direction with respect to the fixed bed 21 and the head 3.

The several magnetic clutches and brakes for controlling the shafts 14 and 39 are of a quick acting positive type and are of the Same general construction, as shown in detail on an enlarged scale in Fig. 5, which also illustrates the drive for the head 3 through the fly wheel 15. As previously pointed out, the fly wheel 15 is connected to the motor 16 through the belt 17, and the hub 15a of the iiy wheel 15 is supported for free rotation about the axis of the shaft 14 by bearings 50. One element of the magnetic clutch 19 is mounted on the fly wheel 15 and consists of a body 51 composed of magnetic material within which is located coils 52 adapted to magnetize the body 51, when energized. The coils 52 are adapted to be supplied with electrical current from a slip ring 53 mounted on the hub 15a of the iiy wheel 15, with the slip ring being engaged by brushes 54 carried by a fixed brush holder 55, so that the coils 572 can be energized while the fly wheel is rotating.

The other element of the magnetic clutch 19 consists of an armature disc 56 composed of magnetic material and mounted on pins 57 carried by a driving sleeve 58 secured to the shaft 14 by means of a key 59. Therefore, when the coils 52 are energized, the disc 56 will be attracted to and held by the face of the rotating magnetized body 51 to cause the sleeve 58, and the shaft 14 to rotate in unison with the fly wheel 15 and thereby drive the crank shaft 8 at a relatively slow speed, through the reduction obtained through the large gears 9 and 12. The magnetic clutch 19, therefore, provides means for quickly and positively connecting the shaft 14 to the fiy wheel 15, or to disconnect it therefrom, so as to control the movement of the press head 3 independently of the driving motor 16 and the rotation of the fly wheel 15.

The magnetic brake 20 is for the purpose of quickly bringing the shaft 14 to rest after it has been disconnected from the fly wheel 15 through deenergization of the clutch 1 9. One element of the brake 20 consists of a body 60 mounted in a bracket 61 secured to a frame member 1., with the body surrounding one end of the shaft 14 adjacent to the sleeve 58. The body 60 provides energizing coils 62, whereby the body may be magnetized so as toy attract the other element of the brake which consists of a magnetic armature disc 63 supported on the sleeve 58 by pins 64. Therefore, energization of the coils 62 will cause the disc 63 to be attracted to and held by the stationary body 60 to bring the shaft 14 to a quick stop and therebymaintain the head 3 at any given position in its travel with relation to the fixed bed 21.

The magnetic clutches 47 and 48 shown in Fig. 6, are of the sameV general construction as described above with reference to the clutch 19. Therefore, it is sufficient for the purposes of the present application to state that the clutch 47 consists of a body 65 mounted on the motor shaft 43, with the body 65 providing energizing coils 66 which l serve to magnetize the body and attract an armature disc 67 mounted on the shaft 45 leading into the transmission 38. The clutch 48 similarly provides a body 68 mounted on the motor `shaft 44, with coils 69 serving to magnetizey the body 68 and attract an armature disc 70 mounted on the shaft 46 leading into the transmission 38. Therefore, the clutch coils 66 and 69 provide means for quickly and positively connecting the shaft 39 of the transmission to either motor 41 or motor 42, to thereby control the direction of travel of the chains 32 and the associated slide 29, and consequently, the direction of travel of the cutting table 22 with respect to the bed 21.

The magnetic brake 49 serves the purpose of bringing the transmission shaft 39 to rest following the disconnection of either motor 41 or 42 from the transmission 38, through operation of the clutches 47 or 48; The brake 49, in common with the brake 20 provides a body 71 mounted on a fixed bracket 72 and enclosing energizing coils 73. Upon magnetization of the body 71 by the coils 7-3, a

magnetic armature disc 74 on the shaft 39 will be attracted to and held against rotation by the stationary body 71,

thereby bringing the shaft 39 to a quick stop and with it the cutting table 22.

In view of the foregoing, it is apparent that the clutch coils 52, 66 and 69, provide electrical means for quickly and positively controlling movement of either the head 3 or the worktable 22, so that either of these elements can be driven selectively by the electric motors 16, 41 or 42. Furthermore, the brake coils 62 and 73 provide electrical means for quickly and positively bringing either the head 3 or the table 22 to rest following deenergization of any of the magnetic clutches, thereby rendering the stopping point of either the head 3 or the table 22 independent of the continued running of the driving motors 16, 41 or 42, all as will more fully appear from a consideration of the functioning of the separate electrical control circuits for the motors and the clutch and brake coils, which will next be described.

Referring now to Fig. 8 there is shown a schematic wiring diagram for automatic control for the press, whereby the table 22 carrying the work W is caused to go through an operating cycle to position the die D under the head 3 for the performance of a blank cutting operation by downward movement of the head 3, followed by withdrawal of the table 22 from over the bed 21 to a position in which the die D can be conveniently reached by the operator. An important element in this automatic operating cycle consists of a light beam projected across the top of the cutting board from a suitable light source, such as a lamp carried by a holder 76 mounted on the right-hand frame member 1, as viewed in Fig. 3. The lamp 75 is adapted to project a ray of light L across the worktable 22, above and parallel to the at surface of the work W, and normally the light ray L enters a photoelec tric cell 77 carried in a holder 78 mounted on the lefthand frame member 1. Both holders 76 and 78 are vertically adjustable, as will later appear.

The passage of the light ray L is indicated by the dot and dash line in Figs. 2 and 3 and it is obvious that the cell 77 will remain energized until such time as it may be interrupted by the movement of the cutting die D with the table 22, upon initiation of the operating cycle of the press by connecting the driving chains 32 to the motor 41 through the clutch 47.

Referring again to Fig. 8, the driving motors 16, 41 and 42, as well as the electrical control circuits therefor are adapted to be energized from a suitable source of electrical energy, as represented by the supply mains 79 under the control of a main line switch 80. The three motors 16, 41 and 42 are adapted to be connected to the supply mains 79 upon the closure of the contacts 81 of a motor contactor M, the operating winding 82 of which is in a control circuit that is energized from control conductors 83 and 84 leading from the terminals of the secondary winding 85 of a transformer, the primary winding 86 of which is continuously energized from the mains 79. The contactor winding 82 is in circuit with the normally open contacts 87 of a motor starting switch 88 of the push button type, as well as the normally closed contacts 89 of a motor stopping switch 90. Therefore, when it is desired to start and run the motors 16, 41 and 42, preparatory to operating the press, closure of the switch 88 will energize the contactor winding 82 and the resulting closure of contacts 81 will simultaneously connect the three motors across the supply mains 79. Since the magnetic clutches 19, 47 and 48 are then deenergized, running of the motors 16, 41 and 42 will not have any effect on the head 3 or the table 22, then in the position shown in Figs. 1 and 3.

Upon closure of the motor starting switch 88 a holding circuit for the contactor M will be established through con- 4 tacts 81a to the right-hand contact 87 of this switch, so contactor M will remain closed until stopping switch 90 is opened. Closure of contacts 81a also serves to energize a control conductor v91 leading to a number of relays and other devices forming part of the control circuit. As will later appear, these devices may be energized through connection between the conductor 91 and the continuously energized control conductor 84, but before entering intoa detailed description thereof there will be next described, the general arrangement of the circuits for energizing the lamp 75 and photocell 77, as well as the operating coils for the magnetic clutches and brakes.

The lamp 75 for energizing the photocell 77 is adapted to be illuminated from a small transformer 92, the terminals of which are connected across the control conduc tors 84 and 91. Therefore, upon closure of the motor starting switch 88, and pulling in of motor contactor M, the transformer 92 will be energized to illuminate the lamp 75 and cause the light ray L to be projected across the table 22 above the work W so as to energize the photocell 77. The cell 77 is connected by a conductor 93 to a relay 94, which employs a tube 95 that is energized from the control conductors 91 and 84, with the cell 77 being adapted to vary the output of the tube. The photocell relay also includes a winding 96 in circuit with the tube 95, and a pair of normally open contacts 97a,in circuit with the Winding 98 of a time delay relay TD-l, the function of which will be later described. It is sufcient to state, at this point, that the contacts 97a of the photocell relay 94 will remain open as long as the photocell 77 is illuminated, with interruption of the light ray L increasing the output of tube 95, so that the winding 96 will close contacts 97. It is also to be noted that the relay TD-l provides normally open contacts 98a in the circuit of the winding 99 of a second time delay relay rl`D-2, the function of which will later appear.

The control conductors 83 and 84 are depended upon to energize a rectifier R for the purpose of converting the alternating current, as supplied by the conductors 83 and 84, into direct current for operating the magnetic clutches and brakes. The output side of the rectifier R serves to supply direct current to conductors 100 and 101, across which the energizing coils 52, 66 and 69 for the clutches and the energizing coils 62 and 73 for the brakes are connected in response to the closure of contacts provided by additional control relays. The operation and function of these relays will next be described with reference to their control over the circuits that are successively completed between the direct current conductors 100 and 101,. through the clutch and brake coils to obtain a complete operating cycle of the press through energization or deenergization of the several magnetic clutches and brakes, in a predeter- 1 mined sequence.

For the purpose of initiating the start of an operating cycle, the control system shown in Fig. 8 provides a cycle starting switch 102 of the push button type which provides a pair of normally open contacts 103 in the circuit of the winding 104 of a master control relay CRM. This circuit also includes the normally closed contacts 105 of a master stop switch 106, also of the push button type, through which a control conductor 107 is continuously energized from the conductor 91. Therefore, upon depression of the switch 102 to close its contacts 103, the

relay CRM will be energized to close its contacts 10411 and thereby establish a holding circuit for the relay winding 104 from the conductor 107, even though the switch contacts 103 open as soon as pressure is released on the 1f button of the cycle starting switch 102. This holding circuit for the relay winding 104 also includes a pair of normally closed contacts 108e forming part of a third time delay relay TD3 having a winding 108. The master relay CRM will, therefore, remain energized through its holding circuit as long as the contacts 108a remain closed.

The operation of the cycle starting switch 102 also serves to close momentarily a second pair of contacts 103a in the circuit of the winding 109 of a relay CRI which is utilized to initiate inward movement of the table 22 by closing the circuit of the coil 66 of the magnetic clutch 47,

through a pair of normally open contacts 109e leading from the left-hand direct current conductor 100. The relay CRI also provides a pair of holding contacts 109b which are closed in response to depression of the cycle starting switch 102 to establish a holding circuit for the relay winding 109. It is to be noted that this holding circuit 109b for relay CRI is energized from a conductor 110 which is energized from conductor 107 through the holding circuit 10451 for the master control relay CRM. Therefore, depression of the cycle starting switch 102 performs thedouble function of energizing relays CRM and CRI, which are held in through their holding circuits when the button of the switch 102 is released. As a result of the energization of relay CRI, the relay contacts 109:1 in circuit with the clutch coil 66 will be closed, and the motor 41 will drive the chains 32 so as to cause the table 22 to move inwardly over the bed 21 in order to carry the die D on the work W beneath the then raised head 3. It is to. be noted that the energization of the coils 66 of the clutch 47 is accompanied by deenergization of the coils 73 of the brake 49 through the opening of a third pair of contacts 109e of the relay CRI, that are normally held closed when the relay winding 109 is deenergized.

The relative positions occupied by the parts of the press at the start of an operating cycle are shown diagrammatically in Fig. ll, which depicts the die D at a forward location on the work W. Because of this forward location the die D will interrupt passage of light ray L to photocell 77 after only a relatively short travel of table 22, from its starting position, Fig. l1. On the other hand, if the die D has a rearward location on work W, a much longer inward movement of table 22 by motor 41 will occur, before the die D interrupts said light ray L. In any event, when such interruption occurs, be it early or late in the tables inward movement, the contacts 97a of the photocell relay 94 will close to establish a circuit through the winding 98 of time delay relay TD-1, the time element of which is set to cause closure of its contacts 98a in the circuit of the winding 99 of the time delay relay 'TD-2, while the die D is still passing through the light ray L. l

The energization of the time delay relay TD-2 will be accompanied by the closure of a pair of contacts 99a to provide a holding circuit for the relay winding 99 so that the time delay element of this relay will continue in effect, in spite of the reopening of the contacts 97 of the photo relay 94, as the continued movement of the die D permits the light ray L to reenter the photocell 77 and again bias the relay tube 95. It is to be noted that the holding circuit for the time delay relay TD-2 also includes a fourth pair of contacts 1096! of the relay CRI which has previously energized the clutch coil 66 for causing inwardv movement of the table 22. These contacts 109d are normally open and remain so until the relay winding 109 has been, energized by closure of the cycle starting switchl 102. Therefore, accidental interruption of the passage ofthe light ray L to the photocell 77 will not have any effect. on the time delay relay TD-2, unless the relay' CRI has been previously energized and the table is moving inwardly.

The'time delaytelement of the relay TD-2 is so set, that as the die D approaches a position in which it is centered over'the bed 21,' as shown in Fig. l2, a pair of normally open contacts 9917 in the circuit of the winding 111 of a head control relay CRH will close, as indicated in dotted lnes-in Fig. 8. As previously pointed out, the head 3 is returned to the top of its stroke at the end of each operating cycle and the downward movement of the head 3 is under the control of the time delay relay TD-2 which, turn, is` adapted to be energized by the time delay relay "FD-1 a predetermined interval after closure of the contacts 97a ofv the photocell relay 94, in response to inward movement ofthe die D'on the table 22.

- For they purpose of controlling the movement of the head 3, the relay CRH'provides a pair of normally open Cil contacts 111a in the circuit of the coil 52 of the head clutch 19, aswell as a pair of normally closed contacts 111!) lin vthe circuit of the coil 62 of the head brake 20. Therefore, when relay winding 111 is energized from the control conductors and 84 upon the closure of the normally open contacts 99b of the time delay relay TD-Z, the closure of contacts 111a and opening of contacts 111b energizes the clutch coil 52 and deenergizes the brake coil 62, whereupon the head 3 starts to move donwwardly. After the head has moved a short distance, a holding circuit for the relay winding 111 is established through the closure of contacts 112 forming part of a limit switch LS-l which is mounted so as to be actuated by rotation of the crank shaft 8 which drives the press head 3. As best shown in Fig. 4, the limit switch LS-l is mounted just above the crank shaft 8 on one of the plates 27 and provides an arm 113 riding on a timing cam 114 rotatable with the crank shaft 8. The cam 114 provides a projection 114a which engages the arm 113 to hold the contacts 112 open whenever the head 3 reaches the top of its stroke.

Therefore, a's soon as the head 3 starts its downward movement in response to energization of relay CRH through closure of time delay contacts 99b, the closure of limit switch contacts 112 will establish a holding circuit for the relay winding' 111 which will maintain the relay CRH energized during one complete revolution of the crank shaft. However, should the passage of light to the photocell 77 be interrupted after the head 3 starts down, as by an operator reaching for the die D, a pair of normally closed contacts 97h of the cell relay 94, in circuit with winding 111, will open, thereby deenergizing relay CRH and stopping the head.

The holding circuit for the relay winding 111 also includes apair of contacts 111C, which are normally open, so that these contacts will be closed in immediate response to energization of relay CRH to maintain the circuit of the relay winding 111 as soon as the contacts 112 of the limit switch LS are closed. Therefore, when once the head 3 starts its downward movement, the circuit of the relay winding 111 will be maintained through the limit switch contacts 112 while the crank shaft 8 makes one complete revolution during which the die D is forced downwardly through the work W, on the then stationary table 22, as indicatedin Fig. 13. After this the head 3'wil1 continue its upward movement until it reaches the top of its stroke, where it` will stop, always in the same place, due4 to the opening of limit switch contacts 112 by the cam projection 1.14m

In order to bring the moving table 22V to a stop, as well as to prevent any inward movement of the table 22 when the head 3- occupies any position other than its top position, the limit switch LS-l provides a second pair of contacts 112`a which are located in the circuit leading to the winding 109 of relay CRI, whose energization is necessary in order to operate the clutch 47, as previously pointed out. The contacts 112e are closed when the head 3 is at the top of its stroke, which position it should occupy at the end of each operating cycle. The fact that these contacts 112:1 will open as soon as the arm 1.13 of the limit switch LS-l passes off the cam projection 114a, insures deenergization of the relay CRI to' bring table 22 to` a stop with the die D properly positioned beneath the then moving head 3, well in advance of the die-cutting operation. In other words, regardless of how far the table 22 may have moved inwardly, from starting position, to carry die D into intersecting relation to light ray L, the inward table movement, after such intersect-ion occurs, is of fixed and constant length, so as to insurerproper.positioning of said die, squarely beneath the headl 3.

The outward movement of the table 22, after a cutting operation on the work W by the head 3- and die D, is under the control of a relay CRO providing a winding 115 and a first pairV of normally open contacts 115a in the 75 circuit ofthe coil 69 for the clutch 48 and a second pair of normally closed contacts 115b in the circuit of the coil 73 of the brake 49. The relay is adapted to be energized' from the control conductors 110 and 84 through a circuit the relay CRI which, as previously pointed out, is deenergized except when the table 22 is moving in. The circuit of relay winding 115 also includes a pair of normal# ly open contacts 116 forming part of a second limit switch LS-2 mounted on the plate 27 beside the limit switch LS- 1. This switch LS-2 provides an arm 117 bearing on a cam 118 mounted on the crank shaft 8 and the contacts 116 remain open except for a short period of time during which they are closed by a projection 118g on the cam 118.

As indicated in Fig 13, the cam 118 is so mounted with relation to upward movement of the head 3 that the contacts 116 of limit switch LS-2 will be closed just after the head 3 starts to move upwardly and is clear of the top of the die D, which at that time has been pressed downwardly through the work W to cut a stack of blanks therefrom. At this moment, table 22 is stationary and is positively held against any movement by the brake 49, the coil 73 of which is maintained in an energized condition through the then closed contacts 109e and 115b of the deenergized relays CRI and CRO, respectively.

Upon closure of the limit switch contacts 116 by the cam projection 118, an energizing circuit is established for the winding 115 of the relay CRO, and as the relay pulls in, a holding circuit is established through contacts 115C, which serve to maintain the circuit after the limit switch contacts 116 are opened. The above described pulling in of the relay CRO in response to operation of the limit switch LS-2, causes closure of contacts 115a in the circuit of clutch coil 69 and opening of contacts 115b in the circuit of brake coil 73. This results in clutching the motor 42 to the shaft which drives the chains 32 so as to move the slide 29 to the left, as viewed in Fig. 1, to cause outward movement of the table 22 with the die D remaining in the work W, as shown in Fig. 14. At this time, the head 3 is still moving upwardly away from the bed 21 and the table 22 will continue its outward movement until it is automatically brought to rest by functioning of the third time delay relay 'TD-3. The energizing circuit for the winding 108 of this relay is established between the control conductors 110 and 84 by closure of a pair of contacts 115d forming part of the relay CRO, so that the time delay starts to run with outward movement of thetable 22. Energization of relay CRO also opens contacts 115e in the circuit of relay CRI and closes contacts 115f in circuit with winding 111 of CRH, so that upward head movement will continue, even if photocell relay contacts 97b should open.

As previously pointed out, the time delay relay TD-3 provides a pair of normally closed contacts 108:1 in the holding circuit for the winding 104 of the master control relay CRM. Therefore, as the time delay element runs out, the contacts 108:1 will be opened to deenergize the relay CRM and thereby disconnect the control conductor 110 from the control conductor 107 through opening of the holding contacts 104a of the master relay. This iinmediately results in deenergization of the winding 115 of relay CRO and the table 22 comes to rest as the magnetic brake 49 is again energized by the coil 73 following reclosure of contacts 115b. The fact that the contacts 10S/1 will reclose following deenergization of the winding 108 time delay relay TD-3, does not make any difference, because by that time the holding contacts 104a of relay CRM will have opened and there is no way in which the control conductor 110 can be energized again, other than by operation of the switch 102 which starts the cycle in operation.

The net result of the functioning of the time delay relay TD-3 is to bring the table 22 to rest in a position where the die D is fully withdrawn from the bed 21, with the table always traveling a predetermined distance away from its cutting position over the bed 21, depending upon 10 the setting of the time delay element of the relay TD-3. This position is shown in Fig. 15, it being noted that before the table 22 comes to rest, the head 3 will have returned to the upper end of its stroke and will have come to rest in that position due to the opening of the contacts 112 of the limit switch LS-l. Therefore, the completion of the outward movement of the table 22 marks the end of -the operating cycle that was initiated by operation of the cycle starting switch 102.

By reason of the deenergization of the control conductor 110 at the end of an operating cycle, all of the relays and switches forming part of the control circuit will return to the condition in which they were in at the start of the operating cycle, as shown in Fig. 8, in which it is assumed that the several relays are all in a deenergized condition, with their associated contacts either open or closed, as the case may be. Therefore, at the end of each operating cycle and before the start of another cycle, the several relays CRI, CRH, CRO, TD-1 and TD-2, can be energized only by manual operation of the cycle starting switch 102 which controls the master relay CRM whose energization is dependent upon to connect the control conductor 110 to the control conductor 107. At this time, however, the brakes 20 and 49 are energized to prevent any turning of the crank shaft 8, or any movement of the chains 32, due to the fact that the brake coils 62 and 73 are energized from the rectifier 99 through the then closed relay contacts 109C, 111b and 115b, respectively.

If at any time during the pro-gress of an operating cycle, any emergency should arise which requires immediate stoppage of either the head 3 or the table 22, that portion of the control circuit beyond the conductor 91 can be immediately deenergized by depression of the master stop switch 106 to open its contacts 105. This will cause f deenergization of any one of the three relays CRI, CRH

or CRO controlling the clutch coils 66, 52 or 69, respectively, whereupon any moving part of the machine will be brought to rest by either the brake 20, or the brake 49, the magnetizing coils of which receive their energy from the transformer secondary 85 through conductor 83, as long as the main switch is closed.

If for any reason the downward movement of the head 3 should be prevented by a misplaced die or waste material, as it nears the lower end of its stroke, the head will be stopped by functioning of yan overload switch 119 in the circuit of the motor start switch 88. This overload switch 119 provides normally closed contacts 120 of the type that are tightly held closed by spring pressure up to the point where the contacts are disengaged with a snap action upon application of an opening force, a switch of this type being known as a micro-switch. The switch 119 is located at a point near the middle of the head 3, where any deflection of the head with respect to the slides 4 will result in opening of the switch contacts 120 with a snap action.

Therefore, should downward movement of the head 3 at any time be prevented by a resistance sufliciently great to result in upward deflection of the head with relation to the downward pull of the connecting rods 5, the circuit of the winding 82 of the motor contactor M would be broken to stop the motors 16, 41 and 42. Furthermore, the opening of the overload contacts 120 would disconnect the main control conductor 91 from the transformer winding 85 and the resultant deenergization of the head clutch 19 would be followed immediately by application of the brake 20 to stop the crank shaft 8, even though the fly wheel 15 may continue to rotate after its driving motor 16 has been disconnected. The same general results, as to stoppage of the motors, will be obtained by pushing the motor stop switch to open its contacts 89.

In addition to the above described devices for controlling the press on the basis of an automatic operating cycle,

the present invention also contemplates the provision of means for operating the head 3 and the cutting table 22 independently of each other, if desired, as well as to operate the head continuously while moving the cutting board manually, without any cycle control in order to perform special die cutting operations. While various switches necessary for obtaining these results are included in the basic schematic diagram of Fig. 8, the preferred arrangement of all the switches is shown with relation to a control panel P in Figs. 9 and 10, which panel P is mounted on the left-hand frame member 1, see Fig. 3.

1n order to move the head 3 up and down independently of the functioning of the limit switch LS-l, a head jogging switch 121 is provided, the normally open contacts 12101 of which are connected between the control conductor 197 and the winding 111 of the head control relay CRH. This switch is of the push button type and depression thereof to bridge the contacts 12141 will establish a circuit for the relay winding 111, independently of the limit switch LS1 which as previously pointed out, is always open in the top position of the head. Therefore, by manually depressing the switch 121, it is possible to o-perate the relay CRI-I and move the head through energization of the head clutch 19 upon closure of relay contacts 111a.

Should it be desired to move the cutting table 22 out at any time, as for the purpose of disconnecting the table from the operating slide 29, this may be accomplished by means of a switch 122 which is also of the push button type. This switch provides normally open contacts 12241, one of which is connected to the control conductor 107, while the other is connected directly to the winding 115 of relay CRO through the normally closed contacts 109e of relay CRI. Therefore, depression of the switch 122 will operate the relay CRO, independently of the open contacts 116 of the limit switch L`S-2, so as to energize the coil 69 of the clutch 48 of the motor 42. In this way the chains 32 may be driven to the point where they will become disengaged from the head 29 as the drive block 31 clears the left-hand dog 30, After this the cutting table 22 may be disconnected from the slide 29 by withdrawing the coupling pin 2S, so that the board can be thereafter freely moved on the rollers 23, which is sometimes desirable when utilizing very small cutting dies, or to perfo-rm a special pressing operation without the use of a definite operating cycle, as later described.

Having described the various parts entering into the present invention, there follows a summary of the manner of operating the machine to produce blanks from various kinds of material by cutting dies, either on the basis of an automatic operating cycle', or by hand operation, as may be desired. Assuming that the parts of the press occupy the relative positions shown in Figs. l and 2 and that the electrical control devices are in the condition shown in Fig. 8, the operator places the die D on the surface ofthe work W', usually in a position adjacent to one corner of the work where it is nearest the head 3, as when starting on a fresh pile of paper sheets from which envelope blanks are to be cut.

Assuming also that the operator wishes to operate the press on the basis of automatic cutting cycles, the hrst step after closing switch 80, resides in depressing the motor starting switch 88, designated Motor start on the panel P, which results in setting all 3 motors, 16, 41 and 42 in operation, as indicated by the illumination of a red lamp Q on the panel P. As previously pointed out, closure of the main line switch 80 to energize the control transformer 86 has previously energized the rectifier R, so that the brakes 20 and 49 are already energized to hold the crank shaft 8 and the chain shaft 39 against rotation', consequently the parts of the press remain absolutely stationary when the motors are started.

The next step resides in depressing the cycle starting switch 192 which is designated Cycle Start, on the panel P, whereupon the cutting table 22 with the work W and die D thereon, starts to move inwardly beneath 12 the then raised head 3. At this time the light ray L fromV the lamp 75 is passing across the table above the upper surface of the work W, so that interruption of the ray by the moving die causes closure of the photocell relay contacts 97a with resulting energization of the winding 9S of time delay relay TD-l. The delay element of this relay is such that the contacts 98a in circuit with the winding 99 of time delay relay TD-2 will not be closed until the die D has substantially completed its movement through the light ray as indicated in dotted lines in Fig. l2, which show that the die has reached a position wherein it is partially under the head 3. It is 'to be noted that at this stage of the operating cycle, while the die is movingv through the light ray, the other pair of contacts 97b of the photocell relay will be open, so that the circuit. for the Winding 111 of the relay CRI-I cannot be completed until after passage of the die permits the light ray to reenter the photocell 77.

The delay element of relay 'TD-2 is so set that as the die D reaches a position wherein it is substantially centered beneath the head 3, as indicated in full lines in Fig. 12, closure of its contacts 99h energizes the winding 111 of the relay CRH, since by that time the contacts 97 b of the photocell relay 94 have reclosed. When the relay CRH is energized, the resulting closure of contacts 111a in the circuit of the head clutch coils 52 starts the downward movement of the head 3 which continues until it engages the die D and presses the same through the work D, as shown in Fig. 13. This is the normal operation of the head, but as previously pointed out, any interruption of the light ray after the head has started its downward movement will result in bringing the head to a stop due to the opening of the photocell relay contacts 97b. This automatic stoppage of the head 3 is an important safety feature of the machine, since the head will stop should the machine operator attempt to reach in to adjust the die, after it has cleared the light ray, and is under the downwardly moving head.

As the head 3 starts downwardly, opening of the contacts 112s: of limit switch LS1 opens the circuit of the winding 109 of relay CRI. thereby stopping the table 22 in the position of Fig. 12. The table is positively held in its position beneath the head 3 by the magnetic brake 49, the coils 73 of which are energized through the then closed contacts 109C of the relay CRI. The table 22 is held stationary as the head 3 completes its downward stroke to press the die D through the work W, after which the head starts to move upwardly. As the head clears the Work as shown in dotted-lines in Fig. 13, closureof the contacts 116 of the limit switch LS-2 energizes the winding 115 of relay CRO to start outward movement of the table 22 through energization of the clutch 48 by closure of the contacts 115a in circuit with the clutch coils 69. This outward movement of the table 22 con-v tinues under the control of time delay relay TD-3, the

winding 108 of which is energized upon closure of the contacts 115d of relay CRO. The delay element of relay 'TD-3 is set so that the relay contacts 10st: in the circuit of the winding 104 of the master control relay CRM will open after the table has returned to a predetermined position which is convenient to the operator. The resulting dropping out of relay CRO deenergizes the clutch 48 and reenergizes the brake 49 through opening of contacts 115a and closure of contacts 115b, thereby bringing the table 22 to rest at a predetermined distance from the start of its outward movement, as indicated in Fig. 15.

In the meanwhile, the head 3 has continued its upward movement from the position of Fig. 13 and as the head reaches the top of its stroke it will be brought to rest by opening of the limit switch contacts 112 to break the circuit of the winding 111 of relay CRH. The stoppage of the head 3 at the top of its stroke serves to complete the automatic operating cyclefof the press so, that the parts will again occupy the position of Figs. 1 and ll.

It is to be noted at this point that when once the outward movement of the table has been started by closure of relay CRO, the upward movement of the head 3 will continue, even if the light ray is interrupted. This is because closure of the contacts 115f of relay CRO in the circuit of the winding 111 will maintain the circuit of the winding, in spite of the opening of the photocell relay contacts 97b. This arrangement prevents upward movement of the head being stopped should the die D, or waste material, project above the surface of the work W far enough to interrupt the light ray upon outward movement of the table 22.

After the completion of an operating cycle as described above, the operator of the machine removes the die D from the work W with the cut blanks and places the die in another location on the work, preparatory to initiating another operating cycle by again depressing the cycle starting switch 102. The operating cycle then repeats itself with a longer or shorter travel of the work table 22, depending upon the location thereon of die D, and will continue to do so under normal conditions after each relocation of die D on work W, with the various elements of the control circuit performing the functions described above. However, in the continued operation of the press there may arise certain conditions that might result in disturbing the normal course of the operating cycle unless provision is made for meeting such conditions, as will next be described.

For example, continued operation of the press will often result in the accumulation of waste material on the upper surface of the work W in front of the die D, so that there is always a possibility of this waste material interrupting the light ray while the die is still an appreciable distance back of the position of Fig. 11. Assuming that waste material has interrupted the light ray, the time delay relay TD-1 will be energized and its delay element will start to run while the die is still approaching the position in which it would normally cause energization of relay TD-l. However, relay TD-Z is not at this time energized, and the energization of this relay will be further delayed as soon as the passage of the light ray to the photocell 77 is reestablished by passage of the waste material beyond the ray.

When this occurs, operation of the photocell relay 94 will open the previously closed contacts 97a in circuit with the Winding 93 of relay TD-l, thereby stopping the running of the time element until the light ray is again broken by the movement of the die D. The resulting reclosure of contacts 97 starts the delay element of the relay TD-1 running again, so that relay TD-2 will not close its contacts 9913 in circuit with relay CRH until after the die has reached a position under the head, by which time the contacts 97b in the circuit of winding 111 have again been closed through reestablishment of the light ray to the photocell 77, following the passage of the die.

With the above described relation between the functioning of relays TD-l and TD-2, it is possible for the presence of several pieces of waste material to successively interrupt the light ray without energizing the relay TD-2, the operation of which is necessary in order to start the cycle of operations which starts downward movement of the head and brings the table to rest. Therefore, the only way in which the cycle can be started, except by movement of the die D, would be the existence of a rather unusual condition in which the gap between waste material and the die is so great that the time element of relay TD-1 will run out while the die is still outside the light ray. Such an extreme condition might occur with the die D located at the extreme left-hand end of the table for making a final cut through the material. lf due to the presence of waste at the opposite end of the table, the operating cycle is started as a result of the long gap between the waste and the die, then downward movement of the head will be stopped as soon as the die intercepts the light ray, due to the opening of the photocell relay contacts 97b. The stoppage of the head under these conditions will prevent it from engaging the die before the latter is properly centered under the head.

From the foregoing discussion of the functioning of the control relays, it will be apparent that the movements of the table and head are so controlled that the die will be pressed through the work only when properly positioned beneath the head. Furthermore, this cutting operation takes place with a maximum of safety to the operator who cannot reach in to make a last minute adjustment of the die, after the head has started downward, without breaking the light beam and immediately stopping the head. It will be further apparent that the accumulation of waste material on the table will not disturb the operating cycle upon movement of the table in either direction.

As previously pointed out, the lamp and the photocell 77 are vertically adjustable with respect to the frame members l in order to definitely locate the light ray L with respect to the surface of the table 22. The purpose of such adjustment is to take care of variations in the thickness of the material which constitutes the work W, upon the upper surface of which material the die rests prior to the cutting operation.

The arrangement for adjusting the lamp 75 and photocell 77 is best shown in Fig. 3 as consisting of a pair of slides 123 to which the holders 76 and 78 are attached, with each slide 123 providing slots 124 for receiving bolts 125 screwed into a frame member 1. Each slide 123 is therefore vertically alined on a frame member 1 by the bolts 125, with the slots 124 permitting adjustment of the slide with respect to the frame member. When both slides 123 occupy a position wherein the bolts 125 are at the upper ends of the slots 124, the holders 76 and 78 will be at the same level and the light ray from the lamp 75 passes horizontally to the photocell 77 at a predetermined distance above the top of the table 22.

In order to provide for simultaneous adjustment of both slides 123 with respect to the table 22, each slide provides a rack 126, the teeth of which are in engagement with pinions 127 mounted on a shaft 128 extending between the frame members 1 and turnable in bearings 129. The left-hand end of the shaft 128 provides a bevel gear 130 in mesh with a bevel gear 130a at the lower end of a shaft 131 extending upwardly and connected by bevel gears 132 to a shaft 133 carrying a hand wheel 134. By turning the hand wheel 134, the slides 123 can be moved up or down with respect to the frame members 1 so as to locate the light ray at just the right height above the table 22, so it will clear the upper surface of the work. Such adjustment is very necessary in order to compensate for variations in the thickness of the work as well as variations in the depth of the die. Generally speaking, the slides 123 will be so adjusted that the light ray will be intercepted by the center of the die, and after an adjustment has been made through turning the hand wheel 134, the slides 123 can be locked in position by a knob 134a which clampsthe handwheel.

In order to be able to move the head 3 up and down continuously, a switch 135 is provided having a pair of normally open contacts 135e connected between the control conductor 107 and the right-hand contact 121a of the head jogging switch 121. The switch 135 also provides a second pair of normally closed contacts 135b connected between the cycle starting switch 102 and the control conductor 107. The construction of the switch 135 is shown in Fig. 9, from which it is apparent that the contacts 135a will be open when the contacts 135b are closed and vice versa. Therefore, by turning the switch 135 to move its contacts into the dotted line positions in Fig. 9, it is possible to establish a continuous energizing circuit for the relay CRH by merely depressing the head jogging switch 121 long enough to cause the relay CRH to pull in and establish a holding circuit beyond the contacts 135g through relay contacts 111d.

Thus, by operating the switch 135 it is possible to conl tinuously energize the relay CRI-I to cause operation of the head 3 up and down without interruption, as long as the switch 135 is in the dotted line position. During this continuous operation of the head, the transformer 92 and the photocell relay 94 are completely deenergized due to the opening of switch contacts 135b which are located between the control conductors 91 and 107, so that the conductor 91 is dead.

In order to make it impossible for the automatic operating cycle to be initiated while carrying on manual control of the press, a switch 136 is provided with two pairs of normally closed contacts 136@ and 136b in the automatic control circuits for the relays CRI-I and CRO, respectively. The construction of the switch 136 is shown in Fig. 9, from which it is apparent that as long as the switch 136 remains in the position designated Auto on the panel P, the press will be in readiness to function with an automatic operating cycle upon depression of the cycle starting switch 102. However, when the switch 136 is turned into the position marked Hand on the panel P, then the opening of contacts 136e and 136k will prevent any possibility of automatic operation of either the head or the cutting table. The relays CRH and CRO can then be energized only through depression of either the head jogging switch 121 or the switch 122 for moving the cutting table out.

At any time between cycles, the head 3 can be moved independently of the cutting board by depression of the switch 121 which is marked Head Jog on the panel P, provided that photocell relay contacts 97h are closed. The cutting table can be caused to move inwardly and come to a stop beneath the raised head by depressing the cycle starting switch 162 after first turning the switch 136 to the position marked Hand The cutting table can be moved outwardly after such an operation by depressing the switch 122, marked Table Out.

It at any time it is desired to operate the head continuously, then the switch 135 is turned to the position marked Cont on the panel P, thereby deenergizing the control conductor 91 and breaking the circuit to the cycle starting switch 102. With the switch 135 in this posit-ion, it is impossible to move the cutting table 22, other than by hand, and the head can be caused to move up and down continuously by depressing the head jogging switch 121 to close the relay CRH and maintain the head clutch 19 continuously energized through the closed contacts 111a.

From the foregoing it is apparent that by the present invention there is provided an improved press of the die-cutting type that is characterized by its ability to cut large quantities of blanks from sheet material, in accordance with an automatic operating cycle which reduces to a minimum the manual handling of the cutting dies, with a resulting increase in the safety of the operator and the rate of blank production. In the operation of the press on a cycle basis, all movements of the head and worksupporting table are under the control of magnetic clutches since the driving motors, while running continuously, are not effective to move either the head or table, until one or more of the magnetic clutches is energized through functioning of the electrical control apparatus shown in Fig. 8.

As previously pointed out in the description of the functioning of this apparatus, the crank shaft 8 which imparts movement to the h ead 3 is connected to the continuously rotating flywheel 15 only through energization of the magnetic clutch 19, with the shaft 14 being held stationary at all other times by the magnetic brake 20. Consequently, when the clutch 19 is energized and the brake 20 deenergized, the inertia of the rotating iiywheel I'S is available to start downward movement of the head from the top of its stroke, without shock. Furthermore, since deenergization of the clutch 19 is accompanied by energization of the brake 20, as the head completes its stroke and is moving upwardly to its initial position, the

16 head is brought to a stop, without any possibility of overrunning.

The drive for the worktable 22 is also entirely under the control of the magnetic clutches 47 and 48, which function to connect the sprocket driving shaft 39 to either motor 41 or 42, so as to move the chains 32 in one direction or the other, without imparting any shock to the table which is freely supported on the rollers 23 of the cradle 24. As previously pointed out, the actual driving connection between the table 22 and the chains 32 is established by the block 31 which always moves with the chains 32 in order to engage one or the other of the dogs 30. This particular driving connection for the table 22 so functions as to make it impossible for the table to overrun in either direction of movement to the point where it would leave the rollers 23, should either clutch 47 or 4S fail to be deenergized at the proper time so as to bring the table to rest at the predetermined limits of either its inward or outward movement. This functioning of the table drive which makes it impossible for the table to be driven by either motor 41 or 42 beyond a predetermined point, in either direction, is best shown in Fig. 6.

Assuming that the table has come to rest in the position of Fig. 6 due to the normal functioning of the control apparatus, it will be apparent that the drive block 31 is then in engagement with the left-hand dog 30. While the dog 3@ is pivoted on a pin 30a, the block 31 cannot then turn the dog on the pin 30a, because the upper end of the dog is in engagement with a Xed portion of the slide 29 which extends between the dogs. However, should thevchains 32 continue to move towards the left to carry the block 31 past the position of Fig. 6, it Will be evident that as the block 31 travels downwardly around the sprocket 33, it will clear the lower end of the left-hand dog 30, and the table will come to rest even though the chains 32 continue to move.

In the normal operation of the press, with the table 22 at rest in the position of Fig. 6, it is apparent that energization of the clutch 48 will cause the block 31 to start to move towards the right, thereby causing the block 31 to engage the lower end of the right-hand dog 30. While this dog is also mounted on a pivot pin 30a, the dog cannot turn because of its engagement with the fixed portion of the slide 29, so that the table 22 starts to move to the right. Normally, the table will come to rest at a predetermined distance from its starting point, due to the functioning of the photocell 77 and the associated time delay relay TD1, so that the block 31 is still in engagement with the right-hand dog 30 when the table stops. However, if for any reason the control apparatus should fail to function, or should the clutch 48 remain energized too long, as with manual control of the table, then the block 31 will clear the right-hand dog as it travels downwardly around the right-hand sprocket 33, and the table will come to rest.

Due to the pivotal mounting of the dogs 30 on the pins 30a, the driving block 31 is adapted to reposition itself between the dogs after the drive block has become disengaged by moving around either sprocket 33 as a result of the operation described above, which prevents overrunning of the table while connected to either driving motor. Assuming that the block 31 occupies the dotted line position of Fig. 6, wherein it is on the lower side of the sprocket 33, movement of the block around the sprocket in a clockwise direction, will cause it to engage the inclined surface on the lower end of the left-hand dog 311. When this occurs, the dog is free to turn about its pivot pin 36a to permit the block to slide beneath the left-hand dog and then engage the right-hand dog for the purposes of moving the table to the right. Obviously, the right-hand dog is free to turn in the same way to permit passage of the block 31, should the block move from between the dogs to prevent overrunning of the table as it reaches the end of its inward movement.

f, for any reason, the head 3 should engage an obstruction to its downward movement, other than the top of the die D on the work W, then the resulting upward deection of the head under the downward pull of the connecting rods 5, will cause operation of the overload switch 119. The opening of contacts 120 will then immediately stop the motor 16 and deenergize the clutch 19, through opening of contactor M and relay CRH, with the brake 20 being applied to the shaft 14 through the still energized control conductor 83 leading from the transformer secondary 85.

In order to raise the head 3, after it has been stopped by an obstruction to its downward movement, the leads from the motor 16 are provided with a reversing switch 137 which is shown in Fig. 8. This switch is normally closed in the position shown, so that the head 3 is moved through the operating cycle described above lunder the control of limit switch LS-l, the contacts 112 of which remain closed after the head starts its downward movement. Therefore, in order to raise the head 3, after it has once started its downward stroke, it is necessary to reverse the motor 16. The switch 137 when thrown to its other position will accomplish this result, assuming that it is operated in advance of hand closing of motor starting switch SS and head jogging switch 121. The switch 137 is moved to its normal position after the head stops at the top of its stroke by opening of LS-1.

The control circuit also provides limit switches LS-3 and LS-4 (see now Fig. 6) mounted on one of the side plates 27 for the purpose of stopping the table movement when the die is cutting at the extreme outer ends of the work. Under these conditions, the table might strike either the stationary bed, on its inward movement or a stop on its outward movement, due to the fact that the time delay relays would not have time to function in the manner previously described.

The switch TLS-3 provides normally closed contactsV 138 in circuit with the winding 115 of relay CRO and this switch is mounted on the plate 27 so that it will be opened by engagement with the slide 29, as the table nears the limit of its outward movement, as determined by a fixed stop 139, see Fig. 6. Therefore, when the die D is cutting at the extreme inner end of the table 22, at.

the start of operations, opening of the contacts 138 will bring the table to rest before hitting the stop 139, in case the relay TD-3 does not operate in time to perform its normal function in opening contacts 10841, due to the short distance that the table has to travel in its outward movement.

The switch LS-4 provides one pair of normally 'closed contacts 140g in circuit with the clutch coils 66 and a second pair of normally open contacts 140b, in circuit with the coils 73 of the table brake. This switch is mounted on the plate 27 so that it will be operated by engage- Y ment with an extension 141 of slide 29 as the table nears the limit of its inward movement, as determined by the fixed bed 21. Therefore, when the die D is cutting at the extreme outer end of the table 22, at the end of a series of operations, opening of the limit switch contacts 140g and closure of contacts 14% will release the clutch 47 and operate the brake 49 to stop the table. This prevents y the table being jarred by striking the bed, which might otherwise happen should the relay TD-Z fail to operate in time to perform its normal function, due to the short distance that the table has to travel after the die breaks the light beam.

I claim:

l. ln a die-cutting press, a vertically reciprocable head,

"material upon which a cutting die is required to be differ- 18 for initiating downward movement of said head and for bringing said table to rest with said die in cutting position beneath the descending head.

2. The improvement as set forth in claim 1 in which the means for initiating downward movement of said head is actuated in response to the interruption of a light beam by said die as it passes said fixed point.

3. The improvement as set forth in claim 1 in which the means for initiating downward movement of said head is actuated through a time-delay relay in response to the interruption of a light beam by said die as it passes said fixed point.

4. ln a die-cutting press, a vertically reciprocable head, a horizontally reciprocable table for the support of work material upon which a cutting die is required to be dilerently positioned for each cutting operation, means for initiating horizontal movement of said table inwardly towards said head, and means responsive to the inward movement of said die past a predetermined fixed point for initiating downward movement of said head, for bringing said table to rest with said die in cutting position beneath the descending head, and for returning said head after each cutting operation to its former position at the top of its stroke.

5. In a die-cutting press, a vertically reciprocable head,

-to rest with said die in cutting position beneath the descending head, for returning said head after each cutting operation to its former position, and for subsequently moving said table outwardly to its former position.

6. In a die-cutting press, a vertically reciprocable head, a horizontally reciprocable table for the support of work ently positioned for each cutting operation, wherein said work material has a larger surface area than the diecontacting area of said head, means for initiating horizontal movement of said table inwardly towards said head, and means responsive to the inward movement of said die past a predetermined fixed point for initiating downward movement of said head, for bringing said table to rest with said die in cutting position beneath the descending head, for returning said head after each cutting operation to its former position at the top of its stroke, and for subsequently moving said table outwardly to its former position, all of said head and table movements being performed in a complete operating cycle initiated by movement of the die towards its cutting position.

7. In a die-cutting press, a vertically reciprocable head, a horizontally reciprocable table for the support of work material upon which a cutting die is required to be differently positioned for each cutting operation, wherein the surface area of said work material is larger than the die-contacting surface of said head, means for initiating horizontal movement of said table towards said head, means responsive to the inward movement of said die past a predetermined fixed point for initiating downward movement of said head, means responsive to the downward movement of said head for bringing said table to rest with said die in cutting position beneath the descending head, and means responsive to the continued upward movement of said head after the cutting operation for moving said table outwardly to its former position.

8. A die-cutting press comprising in combination, a movable head, a work-supporting table movable at right angles with respect to said head, electric motors for imparting reciprocatory movement to said head and table,

respectively, from a starting position in which said table is withdrawn from the then stationary head for the different positioning.. at each press operation of a cutting die on said work, a source of electrical energy, magnetic clutches for connecting said motors to said head and table, respectively, to cause movement thereof, switch means for connecting said motors to said source to cause continuons operation thereof, switch means for energizing one of said clutches from said source to initiate movement of said table and die with respect to said head, by one of said motors, and means brought into operation by each arrival of said die, in its movements from different starting positions by said table, at a predetermined xed point, for energizing another of said clutches from said source to initiate downward movement of said head by another of said motors, followed by deenergization of the rst clutch to bring the table to rest with said die in position, for engagement by the moving head.

9. A die-cutting press comprising in combination, a movable head, a work-supporting table movable at right angles with respect to said head, electric motors for imparting reciprocatory movement to said head and table, respectively, from a starting position in which said table is withdrawn from the then stationary head for the different positioning, at each press operation of a cutting die on said work, a source of electrical energy, magnetic clutches for connecting said motors to said head and table, respectively, to cause movement thereof, switch means for connecting said motors to said source to cause continuous operation thereof, switch means for energizing one oi said clutches from said source to initiate movement of said table and die with respect to said head by one of said motors, means brought into operation by each arrival of said die, in its movements from different starting positions by said table, at a predetermined fixed point for energizing another of said clutches, after the lapse of a given time interval, to initiate downward movement of said head by another of said motors, and means responsive to the start of such head movement to deenergize the first clutch to bring the table to rest with said die in position for engagement by the moving head.

10. A die-cutting press comprising iu combination, a movable head, a work-supporting table movable at right angles with respect to said head, electric motors for imparting reciprocatory movement to said head and table, respectively, from a starting position in which said table is withdrawn from the then stationary head for the different positioning, at each press operation of a cutting die on said work, a source of electrical energy, magnetic clutches for connecting said motors to said head and table, respectively, to cause movement thereof, switch means for connecting said motors to said source to cause continuous operation thereof, switch means for energizing one of said clutches from said source to initiate movement of said table and die with respect to said head by one of said motors, means brought into operation by each arrival of said die, in its movements from different starting positions by said table, at a predetermined fixed point, for energizing another of said clutches to initiate downward movement of said head by a second motor and to bring said table to rest with said die in position for engagement by the moving head, and means responsive to movement of said head away from the die to energize a third clutch to initiate return movement of said table to its former position by a third motor.

l1. A die-cutting press comprising in combination, a movable head, a work-supporting table movable at right angles with respect to said head, electric motors for imparting reciprocatory movement to said head and table, respectively, from a starting position in which said table is withdrawn from the then stationary head for the different positioning, at each press operation of a cutting die on said work, a source of electrical energy, magnetic clutches for connecting said motors to said head and table, respectively, to cause movement thereof, switch means for connecting said motors to said source to cause continuous operation thereof, switch means for energizing one of said clutches from said source to initiate movement of said table and die with respect to said head, by one of said motors, a light-sensitive cell energized from said source, and normally exposed to a light beam passing across the path of travel of said die at a fixed position along said path, and electrical control devices set in operation by the interruption of said light beam by said die, in its movement from different positions past said fixed position, for energizing another of said clutches from said source to initiate downward movement of said head by another of said motors and to deenergize the rst clutch to bring the table to rest with said die in position for engagement by the moving head.

l2. The combination in a die-cutting press as set forth in claim 8, in which the switch means for controlling the energization of the head and table clutches are actuated in response to a light-sensitive cell and a relay having a time delay element, which is eifective upon interruption of the passage of light to said cell by movement of the die with said table, to initiate movement of the head through energization of its clutch, followed by stopping of the table through deenergization of its clutch.

13. The combination in a die-cutting press as set forth in claim 8, in which the switch means for energizing the head and table clutches are operated in response to a light sensitive cell energized from said source and normally exposed to a light beam passing between said die and head, and a relay having a time delay element which is effective upon interruption of the light beam to said cell by movement of the die with said table, to initiate movement of the head and stopping of the table through energization of another of said clutches and deenergization of the rst clutch after the lapse of a predetermined time interval.

14. The combination in a die-cutting press as set forth in claim 8, in which the magnetic clutch for controlling movement of the head remains energized until said head has made a complete reciprocatory movement toward and away from said table, whereupon said clutch is deener- `gized.

15. The combination in a die-cutting press as set forth in claim 8, in which the energization of said head clutch is maintained until after said head has made a complete reciprocatory movement toward and away from said table, and in which a third clutch is energized to withdraw said table and die from their cutting position in response to the initiation of the return movement of said head away from the die.

16. The combination in a die-cutting press as set forth in claim 8, in which the energization of said head clutch is maintained until said head makes a complete reciprocatory movement toward and away from the table, and in which a third clutch is energized in response to movement of said head away from said die after the cutting operation, followed by the deenergization of said third clutch after the lapse of a predetermined time interval to bring the table to rest in its former position with the die pressed into the work.

17. The combination in a die-cutting press as set forth in claim 16, in which the clutches for operating the head and for causing movements of the table in opposite directions are energized in a predetermined sequence to cause the machine to perform a complete operating cycle, following the energization of the rst clutch to initiate the table movement.

18. The combination in a die-cutting press as set forth in claim 17, in which magnetic brakes serve to hold the head and table against movement, except during the intervals in which said clutches are energized in accordance with the sequence of the operating cycle.

19. In a die press of the class described, a reciprocatory head, a power-driven table for the support and the repeated carriage, into and out of the path of said head, of work material whereon a die member, after each pressing agr/18,260y

operationI of said head thereon, is required to be differently positioned manually with respect to said table and the work material thereon, table actuating'means, responsive to each initiation of said press operation, for moving said table inwardly towards said head, and means responsive to the inward movement of said die past a predetermined iixed point for bringing said table to rest with said die in cutting position beneath said head.

20. In a die press of the class described, a reciprocatory head, a power-driven table for the support and therepeated carriage, into and out of the path of said head, of work material whereon a die member, after each pressing operation of said head thereon, is required to be differently positioned manually with respect to said table and the work material thereon, table actuating means lset in operation by each initiation of said press operation for moving said table inwardly, and means responsive to said dies arrival, on each inward table movement, at a fixed point, for stopping said inward table movement when said die, whatever its position on the work, is substantially centrally disposed in the path of said head.

21. In a die press of the class described, a reciprocatory head, a power-driven table for the support and the repeated carriage, into and out of the path of said head,

of work material whereon a die member, after each y pressing operation of said head thereon, is required to be differently positioned manually with respect to said table and the work material thereon, table actuating means, set in operation by each initiation of said press operation, for moving said table inwardly, and means responsive to said dies arrival, on each inward table movement, at a ixed point, for stopping said inward table movement at a constant distance beyond said fixed point.

22. In a die press of the class described, a reciprocatory head, a power-driven table for the support and the repeated carriage, into and out of the path of said head, of work material whereon a die member, after each pressing operation of said head thereon, is required to be diierently positioned manually with respect to said table and the work material thereon, table actuating means set in operation by each initiation of said press operation for moving said table inwardly, means responsive to said dies arrival, on each inward table movement, at a iixed point, for stopping said inward table movement when said die, whatever its position on the work, is substantially centrally disposed in the path of said head, and means also responsive to said arrival for procuring a working reciprocation of said head.

23. In a die press of the type having a vertically reciprocable head adapted to force a cutting die downwardly through a pile of work material which is supported on a horizontally reciprocable work table, wherein said work table is moved outwardly from beneath said head after each cutting operation for the manual repositioning of said die upon said work material, the improvement which comprises a sensing device located at a fixed position along the horizontal path of travel of said table, said sensing device being energized when said die passes said iixed position as said table is moved towards said head, and a control means responsive to the energizing of said sensing device for stopping the horizontal movement of said table, so that said table will always be stopped when said die is directly below said head, irrespective of the position of said die relative to said table.

24. The improvement according to claim 23 wherein said control means is activated by said sensing device through a time-delay mechanism.

25. In a die press of the type having a vertically reciprocable head adapted to force a cutting die downwardly through a pile of work material which is supported upon a horizontally reciprocable work table, wherein said work table is moved outwardly from beneath said head after each cutting operation for the manual repositioning of ,Said die upon said work material, the improvement which comprises a sensing device adapted to be activated when said die passes a fixed point as said table is moved towards said head for a cutting operation, a rst control means responsive to the activation of said sensing device for initiating the downward movement of said head, and a second control means likewise responsive to the activation of said sensing means for stopping the horizontal movement of said table when said die is positioned directly below said head for the cutting operation.

' 26. The improvement according to claim 25 wherein said iirst control means is energized by said sensing device through a time-delay mechanism.

27. The improvement according to claim 26 wherein said second control means is energized by said sensing device through said time-delay mechanism.

28. The improvement according to claim 25 wherein said sensing device consists of a photoelectric cell which is operable upon the interruption of a light beam to said cell by said die as said die passes said xed point.

29. In a die press having a a vertically reciprocable head and a horizontally reciprocable table wherein said table is adapted to move a pile of work material beneath said head so that a cutting die supported upon said material is positioned directly below said head and wherein said head is adapted to force the die so positioned downwardly through the thickness of said work material, the improvement which comprises an energizing means positioned along the horizontal path of said table between an outer position of said table and said head, said energizing means being activated when said die passes said energizing means as said table is moved towards said head, a motor control means for reciprocating said head, said control means being responsive to the activation of said energizing means to initiate the downward movement of said head, and a braking means for stopping the horizontal movement of said table, said braking means being likewise responsive to the activation of said energizing means, so that said table will always be stopped when said die is directly below said head, irrespective of the position of said die upon said material.

30. The improvement according to claim 29 wherein said energizing means consists of a light sensitive cell which is activated on the interruption to said cell of a beam of light by said die.

31. The improvement according to claim 30 wherein said motor control means is energized by said energizing means through a time-delay mechanism.

32. The improvement according to claim 3l wherein said braking means is energized by said energizing means through said time-delay mechanism.

33. In a die press of the type having a vertically reciprocable head adapted to force a cutting die downwardly through a pile of work material which is supported on a horizontally reciprocable work table, the improvement which comprises a light sensitive device iocated at a fixed position along the horizontal path of travel of said table, said device being activated when said die interrupts a beam of light focused on said device as said table moves said die past said device and towards said head for a cutting operation, a motor control means responsive to the activation of said device for initiating a downward movement of said head, and a braking means for stopping the horizontal travel of said table `simultaneously with the downward movement of said head, whereby said die is always stopped beneath said head at a fixed distance from said device, regardless of the position of said die relative to said table.

34. The improvement according to claim 33 wherein said motor control means is energized by said device through a time-delay mechanism.

35. The improvement according to claim 33 including a second braking means for automatically stopping the reciprocatory movement of said head as it returns to its uppermost position.

36. The improvement according to claim 35 including 23 a secondmotor control means responsive to the operation of said second braking means for withdrawing said table from beneath said head, so as to permit the repositioning of said die upon said work material for another cutting operation.

37. The improvement according to claim 36' including a third braking means responsive to said second motor control means for deenergizing said second' control means after a xed period of time, whereby saidtable is always stopped at a fixed distance from said head after its withdrawal therefrom.

38. The improvement according to claim 35 wherein said second braking means is adapted to be energized by a subsequent interruption of said beam of light after said motor control means has beenV energized, so as to stop said head instantly.

39. ln a die press of the type having a vertically reciprocable head adapted to force a cutting die downwardly through a thickness of work material supported on a horizontally reciprocable work table, the improvement which comprises a light sensitive device located at a fixed position along the horizontal path of travel of said table, a light source adapted to focus a beam of light upon said light sensitive device, a beam interrupting means adapted to be variably positioned along the table after each cutting operation inV accordance with the location of the next cut, said light sensitive device being activated upon the interruption of said beam of light by said interrupting means as said table moves towards said head, and a braking means responsive to the activation of said light sensitive device for stopping the horizontal movement of said table, whereby saidv table will always be stopped when the location of the next cut is directly below said head.

40. The improvement according to claim- 39 wherein said braking means is activated by said light sensitive device through a time-delay mechanism.

4l. In a die press of the type having a vertically reciprocable head adapted to force a cutting die downwardly through a pile of work material which is supported on a horizontally reciprocable work table, the improvement which comprises a light sensitive device located' at a xed position along the horizontal path of travel of said` table, a light source adapted to focus a beam of light upon said light sensitive device, a beam interrupting means adapted to be variably positioned along the table after each cutting operation in accordance withthe location of the next cut, said light sensitive device being activated upon the interruption of said beam of light by said interrupting means as said table moves towards said head for a cutting operation, a motor control means responsive to the activation of said device for initiating a downward movement of said head, and a braking means for stopping the horizontal travel of said table in timed relation with the downward movement of said head, whereby the travel of said interrupting means beyond said device is constant.

42. The improvement according to claim 4l wherein said motor control means is activated by said device through a time-delay mechanism.

43. The improvement according to claim 41 including a second braking means for automatically stopping the reciprocatory movement of said head as it returns to its uppermost position.

44. The improvement according to claim 43 wherein said second braking means is adapted to be energized by any subsequent interruption of said beam after said motor control means has been energized, so as to stop said head instantly.

References Cited in the le of this patent UNITED STATES PATENTS 928,969 Harris July 27, 1909 1,984,051 Biggert Dec. 11, 1934 2,176,543 Norton Oct. 17, 1939 2,259,320 Novick et al Oct. 14, 1941

Images