US2346719A - Punch press - Google Patents

Description

April 18, 1944. s 2,346,719

PUNCH PRESS Filed Aug. 18, 1942 4 Sheets-She et 1 PIERCING J/G [VI/ENTOE ZEO/V/IBD E. AJKE ZJW L. E. ASKE PUNCH PRESS April 18, 1944.

4 'Sheets-Shee 2 Filed Aug. 18, 1942 April 18, 1 944. s 2,346,719

PUNCH-PRESS Filed Aug. 18, 1942 4 Sheets-Sheet 3 ELECTRIC M/IGNE TIC 63 72 63 STRIP/ EE PLATE ivy/M1702 LEON/JED E. AJKE A TTOENEYJ Patented Apr. 18, 1944 PUNCH PRESS Leonard E. Aske, Minneapolis, Minn, assignor to Dayton Rogers Manufacturing 00., Minneapolis, Minn, a corporation ofMinnesota Application August 18, 19.42, Serial No. 455,251 22 Claims. (Cl. 164-102) This invention relates to new and useful improvements in punch presses, generally, and more particularly to punch presses used for punching various sizes of holes in metal stampings.

Punch presses, as now commonly constructed,

have the punch suitably mounted on the bed plate of the press, and the die is carried by the ram mounted over the bed plate. The blank or stamping to be pierced, is supported in what is commonly known to the trade, as a piercing Jig, which consists of a flat metal plate having the proper size holes jig-bored therein. To this plate is secured a piece of sheet metal, usually produced from a piece of the blanked out part of the metal strip from which the blanks have been blanked. This piece of blanked out metal i riveted to the jig-bored metal plate with the opening therein accurately located with respect to the drilled holes in the Jig plate, and provides what is commonly known to the trade as a "nest." The contour of the opening in the blanked out metal strip is identical to the contour of the blank to be pierced, whereby the blank may readily be placed in the nest of the piercing jig, preparatory to being pierced.

In the operation of a conventional press in which the punch is mounted on the bed plate,

whereupon the ram is actuated and forces the die into piercing engagement with the blank, whereby the punch pierces the blank, as is well known.

To accurately.position the piercing jig with respect to the punch, in a conventional press, often requires considerable time, as the operator cannot see the end of the punch to guide it into the guide hole in the piercing Jig. The operator must therefore guide the piercing Jig around on the tip of the punch until the latter enters the selected guide hole in the Jig. Each time the blankhas been pierced by the punch, the jig is removed from the punch, and the pierced blank knocked out of the nest. A new blank is then placed in the nest, and the sanie v operation repeated. This method is slow because the operator cannot, as a rule, initially place the piercing ill; on the punch whereby the punch will immediately enter the selected guide hole in the Jig, and he must therefore feel his way," or guide the iig plate around on the end of the punch until it enters the selected guide hole in the Jig. Such sliding of the piercing jig on the end of the punch to accurately align it with the punch and die, is also objectionable in that it has atendency to dull the cutting edge of the-punch.

To expedite the operation. of piercing holes in blanks, I have found that by inverting the punch and die in the punch press, the operation ofguiding the Jig plate onto the punch" usual ram of the press which, in the present instance, is mounted for reciprocal movement in a guide provided in the bed plate of the press. When th punch and die are thus inverted in the press frame, the piercing 118 must be correspondingly inverted, whereby the guide holes therein are clearly visible to the operator because they are then exposed to view on the top side 'of the piercing 118. it being understood that the blank to be pierced is then supported in the nest on the bottom side of the 118. By thus inverting the piercing Jig, it will readily be seen that the operation of guiding the piercing iig into accurate registry with the punch is greatly facilitated, as the selected guide hole in the piercing jig is clearly visible to the operator at all times, whereby he may quickly move the Jig into alignment with the punch to properly position the blank with respect to the punch and die.

An object of the present invention therefore is to provide a punch press in which the ram carrying the die is mounted in the bed plate of the press below the punch, and the punch is mounted in the upper portion of the press frame directly over the die, whereby the operator may readily and quickly guide the piercing jig into accurate registry with the punch and die with a minimum of-eiiort and labor.

A further object of the invention resides in the provision of electrical means for holding the piercing Jig in fixed accurate relation with respect to the punch, during the piercing operation, whereby each blank will be accurately pierced.

A further object is to provide an electro-magnetic stripper plate having a normally open control circuit provided with a pair of spaced contacts'which are associated with the stripper plate and so related to the punch that when the piercing jig is accurately guided onto the punch, the piercing jig will bridge said contacts and close the control circuit, whereby the coils in the stripper plate are instantly energized to thereby cause the stripper plate to momentarily become a magnet and draw the piercing jig into firm contact therewith during the piercing operation.

A further object is to provide a punch press provided with means for fixedly supporting a punch, and having a ram mounted for reciprocal movement below the punch and carrying a die, and an electro-magnetic stripper plate being mounted adjacent to the punch and having a connection with a suitable cushioning means, whereby when the die is moved into engagement with the blank byreciprocal movement of the ram, the piercing jig in which the blank is supported, may yield under pressure in such a manner that when the die moves out of engagement with the punch, the stripper plate will strip the blank from the punch in the usual manner.

A further object is to provide a punch press comprising an electro-magnetic stripper plate provided with a control circuit having a pair of spaced contacts which preferably are mounted in the stripper plate and positioned to be engaged by the piercing jig, after the piercing jig has been properly guided onto the lower end of the punch, whereupon the control circuit is temporarily closed and thereby renders the drive clutch operative to drive the ram and move the die into piercing engagement with the punch.

A further object is to provide a press of the character disglosed, comprising an electro-magnetic stripper plate, a drive clutch, a control circuit for the stripper plate and drive clutch, and a circuit breaker for opening the control circuit immediately following the blank-piercing operation, whereby the crank shaft may come to rest at the end of each blank-piercing cycle.

A further object is to provide a punch press comprising an electro-magnetic stripper plate, an electrically controlled drive clutch, a suitable motor, and a safety device mounted adjacent to the punch and operatively connected to a cutout switch interposed in the motor circuit, and also to a cutout switch provided in a control circuit for the stripper plate and drive clutch, said safety device being so constructed that when in normal inoperative position, the motor and control circuits will be open, whereby the press cannot be operated, said safety device requiring that it be manually moved into operative position before the motor can be started and also to condition the control circuit for operation, when a piercing jig is subsequently interposed between the punch and the die in position to bridge a pair of spaced contacts in the control circuit, whereby the ram may be operated' to move the die into piercing engagement with the blank.

A'further object is to provide an electric control means for punch presses'which renders the press substantially automatic in operation, and whereby the usual operation of manually tripping a control lever, as is now common in the o eration of punch presses, is entirely eliminated, the starting of the press depending entirely upon the correct positioning of the piercing jig in relation to the punch.

Other objects of the invention reside in the provision of an-elect'ro-magnetic stripper plate having the dual function of temporary holding a piercing jig during the blank-piercing operation, and which also serves to strip the blank from the punch, when the blank has been pierced; in the unique construction of the clutch operating means, which is operated by a solenoid coil having a normally open circuit which is adapted to be closed by a suitable relay, when the control circuit is closed by the piercing jig to thereby energize the stripper plate; in the provision of a simple and inexpensive control means for a punch press whereby the entire operation of the press may be substantially automatic, and is controlled entirely by the insertion of a piercing jig blank in position with respect to the punch; in the provision of a safety device comprising a movable member positioned adjacent to the punch and die and operatively connected to the motor cutout switch and to a suitable cutout switch in the control circuit, whereby when the safety device is in inoperative position, as when the press is at rest, the motor cannot be started to operate the ram, said safety device being so constructed that it must be moved into operative position in front of the punch and die before the press can be started to pierce the blank.

Other objects of the invention will appear from the following description and accompanying drawings and will be pointed out inthe annexed claims.

In the accompanying drawings there has been diclosed a structure designed to carry-out the various objects of the invention, but it is to be understood that the invention is not confined to the exact features shown, as various changes may be made within the scope of the claims which follow.

In the drawings:

Figure 1 is a view of a. punch press with the invention embodied therein;

Figure 2 is an enlarged detail sectional view of the upper portion of the press frame, showing the electro-magnetic stripper plate and the cushion which operatively supports it;

Figure 3 is a view similar to Figure 2, but showing the ram moved upwardly to force the punch through the blank;

Figure 4 is a front view of Figure 2 with the upper portion of the structure broken away, and

showing the safety device in operative position;

Figure 5 is an enlarged detail sectional view showing the piercing Jig positioned against the stripper plate with the punch received in one of the guide openings thereof;

Figure 6 is a bottom view of the stripper plate, showing the spaced contacts mounted therein;

Figure 7 is a sectional plan view substantially on the line 1--1 of Figure 2;

Figure 8 is an enlarged detail sectional view on the line 8-8 of Figure 7;

Figure 9 is a plan view of the piercing jig showing the guide holes provided therein for accurately positioning theblank with respect to the punch;

Figure 10 is a detail sectional plan view on the lines Ill-40 of Figures 2 and 4;

Figure 11 is a perspective view of the bottom of the piercing jig, showing the nest provided therein for supporting the blank;

Figure 12 is a bottom view of the piercing jig. showing the means for frictionally supporting the blank in the nest;

Figure 13 is a detail sectional view on the line l3-l3 of Figure 1, showing the clutch;

Figure 14 is a schematic wiring diagram showing the electric circuits of the apparatus; and

Figure 15 is a detail view of the upperportion of the stripper plate cushion, showing the knockout pin for the punch.

In the selected embodiment of the invention herein disclosed, there is illustrated in Figure 1, for purposes of disclosure, a punch press including a suitable supporting structure or frame, generally designated by the numeral 2, comprising uprights 3 having a suitable bed plate 4 secured thereto. A shaft 5 is rotatably mounted in suitable bearings provided on the uprights 3, and has a flywheel 6 mounted for relative rotation thereon. The flywheel is shown driven from a motor 1 thru a flexible drive 8.

A clutch, generally designated by the numeral 9, is provided on the shaft 5 for drivingly connecting the flywheel to the shaft. The clutch 9 may be of any suitable construction applicable for the purpose, and in the present instance is shown provided with a hub II which is nonrotatably secured to the shaft. A spring-actuated bolt I2 is slidably mounted in the hub I and has its inner end arranged to be received in one of a series of sockets l3, provided in the adjacent face of the hub of the flywheel, thereby to drivingly connect together the hub I and flywheel 6 for rotation as a unit with the shaft 5, as will be understood by reference to Figures 1 and 13. A suitable spring, not shown, is provided for constantly urging the bolt I into driving engagement with the flywheel 6.

A clutch operating arm I4 is pivoted at l5 to a portion of the frame 2, and has one end adapted to engage a pin or head I6 provided on the bolt l2, thereby to pull the bolt out of driving engagement with the flywheel and interrupt rotation of the shaft. A spring l1 normally holds the clutch control arm M in the position shown in full lines in Figure 13, whereby the bolt I2 is held out of driving engagement with the flywheel. The clutch arm M is adapted to be moved out of engagement with the drive bolt |2 by a suitable solenoid l3, having a connection with the clutch arm l4 through a suitable member l9, shown in Figures 1, 13 and 14.

A ram 2| is mounted in a suitable guide hearing 22 in the lower portion 23 of the punch press frame, proper, generally designated by the numeral 24. The frame 24 is secured to the bed plate 4, although if desired, it may be made integral therewith. The ram 2| is driven from the shaft 5 by a pitman 25 shown having a ball-andsocket connection 26 with the lower end of the ram. The lower end of the pitman is engaged with an eccentric 21 secured to the shaft 5. The

eccentric 21 isso related to the clutch 9, that when the shaft comes to rest at the end of each blank-piercing cycle, the ram will be at the bottom of its stroke, as shown in Figures 2 and 14.

A suitable die, generally designated by the numeral 26, is removably supported on the upper end of the ram 2| by a suitable member 29 shown supported in a socket 30 provided in the end of the ram. The member 29 is retained in the socket 30 by a clamping ring 3| secured to the ram by screws 32. A suitable backing plate 33 is prefer. ably provided in the bottom of the socket 36, to provide an abutment for the lower end of the die 26, as clearly illustrated in Figure 2. The ram 2| is shown provided with a suitable passage 26 which isaligned with a passage 36 in the abutment plate 33. whereby the punchings removed from the blank may pass therethru into a suitable receiving means, not shown in the drawings.

An important feature of the present invention resides in mounting the punch, generally designated by the numeral 34, in the upper portion of the frame 24 of the punch press, over the die 28, as best shown in Figurez, whereby the punch is clearly visible to the operator at all times, when inserting a piercing jig, generally designated by the numeral 35, into accurate alignment with the punch and die.

To support the punch over the die 28, as shown in Figure 2, the frame 24 isshown provided with forwardly extending spaced side members or flanges 36 between which a punch holding block 31 is mounted, as shown in Figures 4 and 10. The

block 31 has opposed flanges 31' seated against the lower edges of the flanges 36 and secured thereto by suitable screws 31". .The block 31 is horizontally adjustable by manipulation of suitable adjusting screws 38 and 39, as best shown in Figure 10. The screws 33 are received in suitable apertures provided in the side frame members 36, and have their inner terminals received in threaded engagement with the block 31. The adjusting screws 39 are received in threaded engagement with a wall 4| of the press frame, and have their inner ends adapted to engage the block 31. By thus supporting the block 31 in the frame 24, it may readily be adjusted in a horizontal plane within certain limits to axially align the punch with the die 28.

The block 31 has a counter bore 42 adapted to receive the usual punch holding cage, generally designated by the number 43, which, as best shown in Figure 2, comprises upper and lower members 44 and 45, secured togetherby suitable bolts or screws indicated at 46. A flanged element 41 is mounted within the lower member 46 of the punch holding cage, and has a socket 46 therein for supporting the punch, as clearly shown. A spring-actuated retaining ball, generally designated by the numeral 46', is mounted in the wall of the socket 40, and is adapted to engage a recess in the shank of the punch 34, in the usual manner, thereby to retain the punch in the socket.

The punch holding cage 43 is mounted for vertical adjustment within the counter bore 42 to properly position it with respect to the die. To thus vertically adjust the cage 43, the upper washer-like member 44 thereof is shown supported on the lower flanged head 49 of a vertically disposed stem 5| having an enlarged threaded portion 52 adjacent its head 49 received in threaded engagement with the block 31, whereby rotation of the stem 5| will vertically translate the stem in the block 31, aswill readily be understood. A sleeve 53 is mounted for rota- 5| between the enlarged of the sleeve 53 is received in threaded engagement with the upper portion 56 of the block 31.

An enlarged washer 66-15 mounted on the sleeve 63 and is seated on the upper end of the portion 66 of the block 41. A similar washer 51 is engaged with the flanged head 58 of the sleeve 63, and a suitable cushion element 59 is moimted on the sleeve 63 between the washers 56 and 61, as clearly illustrated in Figures 2 and 3. The cushion element 59 may be constructed of rubber, or any other material suitable for the purpose.

A suitable handwheel 6| is secured to the upper end of the stem 5| and provides means whereby the stem may be conveniently rotated to vertically adjust the punch with respecttothe die 26. A

' punch from the socket 136, when it is necessary to substituteone punch for another. Such means is shown comprising a knock-out pin 56 slidably mounted in a bore in the tubular member i, and having its lower terminal arranged to engage the upper end of the shank of the punch, as'clearly I illustrated in Figure 2. The upper end of the knock-out pin 50 is provided'with a knob 66 between which and the wheel 60 a suitable spring 16 is mounted. The spring 76 normally retains the knock-out pin in its inoperative position,

shown in Figure 2. I

To remove the punch by manipulation of the I knock-out pin 50, the operator will insert a small pin or wire into an aperture 88 provided in the flanged member 41, in alignment with the retaining ball 40', and move said ball partially out of the,

ascetic piercing jig 36 into accurate alignment with the punch, as will subsequently be described.

Another feature of the present invention resides in the electrification of the stripper plate 65;, whereby, in addition to serving as a stripper plate for removing the pierced blanks from the punch, the stripper plate may also function as a means for firmly holding the piercing jig in position with respect to the punch during the blank-piercing operation. To thus electrify the stripper plate, a

, a series of coils or windings 52 are mounted in annular grooves '13 in the body of the stripper plate, as clearly illustrated in Figure 4. The coils 12 are connected in series with a control circuit,-

generally designated bythe numeral 18, in Figure 14. A pair of spaced contacts I5are provided in the control circuit I4, and are preferably cated in'the stripper plate as adjacent to the punch 34,-as shown in Figure 6. The ends of the contacts 15 protrude downwardly a relatively short distance below the lower surface of the recess in the shank of the punch. The knock-out.

pin may then be operated to quickly eject the punch from the'socket All, to permit another punch to besubstituted therefor.

From the foregoing, it will be noted that the stripper plate 63, as shown in Figures 2 and 8,

whereby they may readily be bridged by the stripper plate 63, when the piercing die is moved upwardly into engagement with the lower face of the stripper plate, as shown in Figure 5. The lower terminal of the punch 2 projects below the bottom surface of the stripper plate 63 a relatively greater distance than the contacts 15, as shown in Figure 4, whereby the mntacts 15 cannot be bridged to close the control circuit until meterwrench or other suitable device may be applied thereto for rotating the sleeve.

Another important feature of the present invention resides in the novel construction of the means for successively stripping the blanks from the punch, following each piercing operation. To thus strip or remove each blank from. the end of the punch, a stripper plate, generally designated by the numeral.63, is removably secured to the lower ends of a plurality of rods 64, having their upper ends received in threaded engagement with the lower plate or washer 56 of the cushion 59. It is to be understood that the plate or washer 56 is adapted for relative sliding movement upon the sleeve 53 thereby to permit compression of the cushion 59, when the stripper plate 63 is thrust upwardly as a result of the ram forcing the piercing die into engagement therewith, during the blank-piercing operation. The rods 66 are slidable in the block 31, as will be understood. The stripper plate 63 is removably secured to the' lower terminals of the rods 64 by suitable lock screws 65 having their inner ends adapted to be received in annular grooves 66 provided in the rods 66, as will be clearly understood by reference to Figure 8. A suitable lock spring 6? is provided on each screw 65 to prevent the screws 65 from accidentally working loose.

As best shown in Figures 2, 6 and 7, the periphcry of the stripper plate 63 has a re-entrant notch Ell therein which is aligned with a cutout portion 69 in the block Bl, whereby the operator has, a clear line of vision, as indicated by the arrow M in Figure 2. In other words, by notching the stripper plate 63 and block 37, as above-described, the entire lower end portion of the punch is always visible to the operator stationed in front of the machine, whereby he may readily guide the minal of the punch 34 has been accurately aligned with'the work as by entering one of the jig-bored holes in the jig plate, as shown in Figures 3 and 5.

The control circuit 14 is shown comprising a wire 16 having one end connected to one of the coils. 12 in the stripper plate, as shown at 11 in Figure 14. The opposite end of the wire 16 may be connected to the fixed contact 18 of a cutout switch 19. other side of the switch 19 to one side of a battery 8!, whose opposite side has a wire 82 connecting it to one side of a coil 83 of a suitable relay, enerall designated by the numeral 84. A wire 86 connects the opposite end of the relay coil 83 to one end of a pivoted arm 86 of a. circuit breaker 90. The arm 86 is adapted to be actuated by a suitable cam 81 secured to the shaft 5 of the press. A contact 88 is secured to the arm 86 adapted to electrically engage a contact 89 provided on a relatively fixed member 8| of the relay 84. A wire 82 electrically connects the member 9| to one end 83 of one of the magnetic coils 12 of the stripper plate 63. It will thus be seen that a complete circuit is provided through the battery 8!, when the arm 86 is electrically engaged with the contact 89, and the spaced contacts 15 of the stripper plate are bridged by the piercing jig 35.

Such closing of the control circuit 14 will have no effect upon the press, unless the drive clutch 9 is operated torelease the drive pin l2 and permit it to engage the flywheel 6, whereupon the punch press will go through one cycle of operation.

To automatically actuate the drive clutch 6, when the control circuit is closed as a, result of the contacts 15 being bridged by the piercing jig, the solenoid coil l8, shown in Figure 14, is electrically connected in the control circuit by a wire as connecting one end thereof to the wire 86, leading to one side of the storage battery 8|. The other side of the solenoid; coil M has a wire 96 conmeeting it to a fixed contact 96, having a complemental contact 9'! electricall connected to the A wire 86 electrically connects the I Y battery 8! through a wire 88. A contact member 88 is shown carried by the armature IOI of the relay coil 83, and is adapted to be moved into electrical engagement with the contacts 96 and 81 to close the circuit between the wires 95 and 98, when the relay coil 83 is energized. The motor I is connected to a suitablesource of current supply through a supply circuit I02, having a suitable cutout switch I03 interposed therein.

Another feature of the invention resides in the provision of a safety device which is so positioned as to prevent an operator from accidentally inserting his hand between the punch and die in the operation of inserting the piercing jig therebetween.

As shown in Figures 2, 3, 4 and 14, the safety device above referred to is shown comprising upright side plates E04, which may be secured to the opposed sides of the lower portion of the frame 24 of the punch press, as clearly illustrated in Figures 3 and 4. The upper edges I of the side plate 904 are spaced above the upper terminal of the die 28, and cooperate to provide a support for the piercing jig 35, as clearly illustrated in Figures 2 and 4.

The piercing jig, as best illustrated in Figures ll and 12, comprises a fiat metallic plate I08 having jig-bored holes l0! and I08 provided therein corresponding to the size and number of holes to be pierced in the blank. These holes are accurately jig-bored in the metallic plate I06, and a nest is then provided on one side of the piercing jig for receiving the blank to be pierced, generally designated by the numeral 809, in Figures 2, 3, 4 and 12. The nest is usually formed by securing to the plate I06 a portion ill of the metal strip from which one of the blanks l09 has been blanked, whereby the contour of the opening H2 in the metal strip I I I will, of course, be identical to the configuration of the blank I09. A suitable friction element H3, preferably of rubber, although it may be of any other suitable material applicable for the purpose, is provided in a wall of the nest I I2 for frictionally supporting the blank E09 therein, while positioning the pierclng jig in alignment with the punch 34.

The friction element H3 is so designed and constructed as to securely hold the blank in position in the nest I I2 while supporting the piercing jig in an inverted position, that is, with the blank on the bottom side of the piercing jig, in the operation of guidin the selected hole therein into alignment with the punch 34.

To prevent accidentaI or premature starting of the press, before the piercin jig has been properly positioned with respect to the punch, the safety device hereinbefore referred to, is provided with a movable guard member or bar H4 which,

when in operation, is positioned in front of the die between the side plates or walls I04 of the safety device. The member H4 is supported by downwardly extending arms H5, pivoted to the frame of the press b suitable pivots H0, as will be understood by reference to Figures 2, 3 and 4. A spring-actuated bolt H1 is mounted in one or both of the arms I I5 01 the safety bar H4, and serves to lock the bar H4 in its operative upright position, shown in Figures 2, 3 and 4. When the spring bolt 1 is pulled outwardly, the bar H4 may be swung forwardly to the dotted line position shown in Figure 3.

When the safety bar I I4 is in its operative position, its upper edge H8 will be disposed in the plane of the upper edges I05 of the side plates I04, whereby the bar H4 will cooperate with said side plates I04 to provide a substantial support for the piercing jig 35, when it is initially inserted between the punch and die in the operation of aligning one of the holes therein with the punch 34, as will readily be understood by reference to Figure 2 and 4.

Another feature of the invention resides in so interconnecting the pivoted safety bar H4 with the control circuit I4 and the motor supp y cir cuit I 02 that when the safety bar is in its inoperative position shown in dotted lines in Figure 3, and full lines in Figure 14, the supply of current to the control circuit l4 and the motor l is cut off, whereby the punch press cannot under any conditions be set into motion, so long as the safety bar is in its inoperative position.

To thus interrupt the supply of current to the control circuit I4 and motor 7!, when the safety bar H4 is in its inoperative position, each supporting arm N5 of the safety bar H4 is shown provided with a switch actuating end portion 6 l9, one adapted to open the motor cutout switch I03, and the other adapted to open the cutout switch it of the control circuit 74. In the wiring diagram shown in Figure it, I have shown the cutout switches I9 and 603 as being actuated by a single switch member Hi. It is to be understood, however, that the two cutout switches are preferably, but not necessarily mounted independently of one another, as shown in Figure 4, one on each side of the press frame, and that the parts are merely diagrammatically illustrated in Figure 1d. The side arms H5 of the safety bar He operate in synchronism, whereby the switches I9 and I03 are always opened simultaneously and closed simultaneously, even though they are mounted independently of one another, as shown in Figure 4. In some instances, however, it may be found more desirable to mount the switches I8 and I08 in a single casing, whereby they may be simultaneously operated by a single switch operating mem- 7 her I2I, as now shown in Figure 14.

In the operatipn of the novel punch press herein disclosed, the blank to be pierced isfitted into the nest I I2 in the piercing jig 85, as will readily be understood by reference to Figures 11 and 12. The piercing jig is then positioned upon the upper edges of the side plates I04 and safety bar H4, as clearly illustrated in Figures 2 and 4, with the blank facing downwardly. The operator aligns the selected aperture I0'I or I08 in the piercing jig with the punch, and lifts the piercing jig slightly upwardly until the lower end of the punch enters the selected hole in the jig. When the punch enters the selected hole in the jig, the jig will engage and bridge the contacts I5 of the control circuit I4, whereupon said cir-' cult is closed through the battery 82 with the result that the electro-magnetic stripper plate 63 is instantly energized and thereby magnetically draws the piercing jig into firm contact therewith, as shown, for example, in Figure 5.

Simultaneously as the stripper plate 63 is energized, the coil- 83 of the relay 84 is energized to cause the member 98 to bridge the gap between the contacts 98 and 8'! and thereby close the circult to the solenoid coil I8 of the drive clutch9. Such energization of the solenoid I8 will cause the clutch bar I4 to be pulled out of engagement with the offset pin or head IQ of the clutch drive bolt I2, thereby permitting said pin to drivingly engage the flywheel 8, whereby the shaft isrotated to operate the ram and move the die into blank-piercing engagement with the punch, as clearly illustrated in Figure 3.

When the punch press is in operation over a period of time, the safety bar H4 is usually left in its operative position, shown in full lines in Figures 2 and 3, whereby the cutout switches '89 and 503 are closed. Under such conditions, the motor I will rotate continuously with the result that the flywheel 6 will also rotate continuously, so long as the safety bar lid is in operative or switch closing position.

Rotation of the shaft 5, however, is temporarily interrupted after each complete revolution thereof as a result of the circuit breaker 90, which is arranged to open or break the control circuit during each half cycle of operation, whereby the solenoid coil 88 of the clutch is de-energized, and, at the same time, the coil 83 of the relay 84 is deenergized. De-energization of the solenoid coil it will permit the spring ll of the clutch arm M to pull said arm upwardly into the path of the pin or head 55 of the driving bolt 82, whereby the driving connection between the shaft and the flywheel is interrupted until the clutch arm is is again actuated to permit the drive bolt 92 to enter one of the sockets B3 in the flywheel.

The operation of the circuit breaker 959 is so timed with respect to the traveling movement of the ram that immediately following the piercing of the blank, as shown in Figure 3, the cam til will actuate the circuit breaker arm at and thereby move its contact 88 out of electrical contact with the fixed contact 89, whereupon the entire apparatus is rendered inoperative, with the exception of the motor l and flywheel S. The relay 8% serves to interrupt the supply of current to the solenoid coil 9 8 from the battery fit, when the ram comes to rest.

At the termination of each cycle of operation, and when the ram is positioned as shown in Figure 14:, the circuit breaker is returned to its closed position, whereby the control circuit W is conditioned for operation the moment the spaced contacts "E5 thereof are bridged by the piercing jig 35, when the latter is moved into engagement with the punch, 'as shown in Figure 5.

From the foregoing it will thus be seen that the entire operation of the punch press is automatically controlled by the insertion of the piercing jig into position between the unch and die. The operation of accurately positioning the piercing die with respect to the punch has also been greatly facilitated by the inversion of the die and punch, whereby the piercing jig may be inverted, as shown in Figures 2, 3 and 4, so that the operator may at all times clearly view the lower end of the punch to guide it into the selected guide opening in the piercing jig. The electromagnetic stripper plate also greatly facilitates the operation of piercing the'blanks in that it practically becomes impossible for the press to be started until the piercing jig, with the blank supported therein, is accurately and securely supported against the bottom face of the, stripper plate t8.

By the provision of the knock-out pin 50, the punch 36 may be quickly removed from its socket fill to permit another punch to be substituted therefor, without removing the electro-magnetic stripper plate from its supporting means. There is ample room in the re-entra-nt notch in the stripper plate for the operator to readily insert a pin into the aperture 80' in the member 41 to render the retaining ball 40' ineffective to secure the shank of the punch in the socket 40, whereby the knock-out pin 50 may radily be operated to eject the punch, when the retaining ball 40 is thus moved into inoperative position.

The novel punch press herein disclosed has made it possible to greatly increase the capacity of such punch presses, with less fatigue to the operator. By mounting the flywheel and all of the operating mechanism of the press below the bed plate 3, the entire press may be made very compact, whereby several such presses may be arranged side by side in a row, or in a semi-circular manner, whereby one operator may operate several machines. This is particularly advantageous when the blank is to have several different size holes punched therein. For example, if a blank is to have three different size holes punched therein, an operator stationed in operative position with relation to three or more machines arranged in close proximity, as above stated, may punch all of the holes in the blank without removing the blank from the piercing jig, by simply moving the jig from one press to the next, each press being provided with a different size punch and die, corresponding to the different sizes of holes to be pierced in the blank.

Thus by grouping a plurality of punch presses as above stated, whereby a single operator may readily and conveniently operate more than one machine, the operation of punching several different size holes in a given blank may be greatly expedited, because the operation of removing the blank from the jig after each different size hole is' punched therein, may be entirely eliminated, and all of the different size holes may be punched with one setting of the blank in the jig. For some classes of work it may be found more desirable to pass the jig with the blank supported therein from one operator to another, each operating a difierent press, and the various presses be equipped with different size punches, whereby a blank which is to have several different size holes punched therein, may readily be pierced without removing it from the jig, by thus passing the jig from one operator to another.

In the drawings I have shown the Control circuit i as receiving its supply of current from a storage battery, but, if desired, it may be supplied from a transformer connected directly to the usual power supply line, without departing from the scope Of the invention. The supply circuit is preferably a low voltage circuit.

It will be apparent to those skilled in the art that I have accomplished at least the principal objects of my invention, and it will also be apparent to those skilled in the art that the embodiments herein described may be variously changed and modified, without departing from the spirit of the invention, and that the invention is capable of uses and has advantages not herein specifically described; hence it will be appreciated that the herein disclosed embodiments are illustrative only, and that my invention is not limited thereto.

I claim as my invention:

1. A punch press comprising a frame including a bed plate having a guide therein, a ram mounted in the guide, operating means for the ram, a die secured to the upper end of the ram, a punch mounted in the frame over the die and operatively aligned therewith and normally spaced from the die, and means for supporting the work between the die and punch and thereafter stripping it from the punch.

2. A punch press comprising a frame including a bed plate having a guide therein, a ram mounted for vertical movement in said guide,

ascetic operating means for the ram, 'a die removably secured to the upper end of the ram, a punch mounted in the frame over the die in operative relation thereto and normally spaced from the die to permit insertion of a blank-supporting jig punch to accurately align the blank with the punch beforethe piercing operation is started.

3. A punch press comprising a frame including a bed plate having a vertical guide therein, a ram mounted in the guide, crank means in the lower portion of the frame for operating the ram, a punch removably supported in the frame above the die in alignment therewith, a yieldable stripper plate supported in the upper portion of the frame forstripping the work from the punch, when the punch has pierced the work, and means whereby the stripper plate may hold the work independently of the operator during the piercing operation.

4. A punch press comprising a frame including a bed plate having a vertical guide therein, a ram mounted for reciprocal movement in the guide, means in the lower portion of the frame for operating the ram, a die removably supported on the upper end of the ram, a punch mounted in the frame over the die in align- -ment therewith and normally spaced from the die to permit insertion of a piercing jig with a blank supported therein between the die and punch, a stripper plate mounted in'the upper portion of the frame, and cushion means for yieldably resisting relative movement of the stripper plate, during the piercing operation, and whereby the blank is stripped from the punch,. when the punch has pierced the blank.

5. A punch press comprising a frame including a bed plate having a guide therein, a ram mounted in the guide, operating means for the ram, a die secured'to the upper end of the ram, a punch mounted in the frame over the die and operatively aligned therewith and normally spaced from the die, a stripper plate mounted adjacent to the punch with its bottom surface spaced upwardly from the lower terminal of the punch, and means for supporting a piercing jig between the die and punch to facilitate guiding the piercing jig into. alignment with the punch.

6. A punch press comprisinga frame including a bed plate having a vertical guide therein, a ram mounted for reciprocal movement in the guide, operating means for the ram, a die removably secured to the upper end of the ram, a punch fixed in theframe over the die and aligned therewith and normally spaced from the die to permit a piercing jig with a blank supported therein, to be inserted between the die ,and punch, and a stripper plate associated with the punch for stripping the pierced blank therefrom, said stripper plate having a re-entrant notch in its periphery whereby the punch is clearly visible to the operator when guiding the piercing jig onto the punch.

7. A punch press comprising a frame having a punch mounted in the upper portion thereof, a guide in the lower portion of the frame, a ram mounted in the guide, driving means for the ram, a die carried by the upper end of the ram,

and a stripper plate mounted adjacent to the punch with its lower face spaced upwardly from the lower terminal ofthe punch, said stripper plate having a re-entrant notch therein whereby the punch is exposed to the operator to facilitate guiding a piercing jig onto the punch in the operation of placing the blank in position between the punch and die.

8. A punch press comprising a frame having a punch mounted in the upper portion thereof, a guide in the lower portion of the frame, a ram mounted in said guide, driving means for the ram, a die carried by the upper end of the ram. a stripper plate mounted adjacent to the punch with its lower face spaced upwardly from the lower terminal of the punch, said stripper plate having a re-entrant notch therein whereby the punch is exposed to the operator to facilitate guiding a piercing jig onto the punch in the operation of placing the blank in position between the punch and die, and means carried by the stripper plate and made operable by engagement with the piercing jig to cause the ram driving means to operate and actuate the punch.

9. A punch press comprising a frame having a guide therein, a ram mounted in the guide, operating means for the ram, an electro-magnetie stripper plate, a die secured to the ram, a punch mounted in the frame in alignment with the die and passing through an opening in the stripper plate and having its lower end spaced downwardly from the bottom face of the stripper plate, a jig for supporting the blank to be pierced, said jig having a guide opening therein adapted to receive the end of the punch to accurately align the blank with the punch and die, and means made operable by engagement with the jig, after the jig has been guided onto the punch, thereby to cause energization of the stripper plate whereby the stripper plate will accurately hold the jig and blank during the piercing operation,

10. A punch pres comprising a frame having a guide therein, a ram mounted in the guide, operating mean-,; for the ram, a die secured to the ram, a punch mounted in the frame in alignment with the die, an electro-magnetic work-holding device and control means for said device positioned to be engaged by the work when the work is inserted between the die and punch, thereby to render said device operable to hold the work in operative relation to the punch during the. piercing operation.

11. A punch press comprising a frame, complementary blank piercing elements "mounted in said frame, one of said elements being fixed and the other movable, operating means for the movable element, a jig for supporting a blank and control means operatively associated with said operating means and comprising a pair of spaced contacts, said contacts being adapted to I prising a pair of spaced contacts, said circuit being operatively associated with the driving means and said contacts being located adjacent to one of the blank piercing elements, whereby when a piercing jig with a blank supported therein is in serted between the piercing elements and bridges the gap between said contacts, the circuit is closed to the driving means, whereby the movable piercing element is operated to pierce the blank.

.13. A punch press comprising a frame, a punch supported in said frame and restrained against axial movement, a die mounted for movement towards and away from the punch, means for driving the die, an electro-magnetic stripper plate positioned adjacent to the punch, a control circuit electrically connected to the windings'of the jig is inserted between the punch and the die, I

whereby the control circuit is closed and causes the stripper plateto become energized to hold the piercing jig in position with respect to the punch, I

during the piercing operation.

' 14. A punch press comprising a frame having a guide therein, a ram' mounted in the guide, operating means for the ram, a die secured to I the ram, a punch mounted in the frame in alignment with the die, a stripper plate mounted ad;-

jacent to the punch for stripping the blank from I the punch following the piercing operation, a

magnetic coil in the stripper 'plate,'a normally open control circuit electrically connected to said coil and operatively associated with the'ram driving means, and spaced contacts in the control circuit adapted to be bridged by a piercing jig in.- serted between the die and punch, whereby the circuit is closed to said coil and to the ram drivr ing means, energization of said coil causing the stripper plate to temporarily hold the piercing jig in accurate position withrespect to the punch.

during operation of the punch to pierce the blank supported in the jig.

15. A punch press comprising a frame having a punch removably supported in the upper portion thereof, a guide in the lower portion of the frame, a ram mounted in said guide, a die removably secured to the upper end of the ram, means for operating the ram, a stripper plate carried on the upper portion of the frame and having its lower face spaced upwardly from the lower terminal of the punch whereby an oper ator may readily and conveniently guide a piercing jig onto the lower end of the punch to accurately position the blank with respect to the punch and die, cushioning means operatively connected to the stripper plate and yieldably resisting movement thereof, control means for the ram driving means, said control means being adapted to be engaged by the piercing jig, when the latter is moved into engagement with the stripper plate, whereby the driving means is rendered operative to actuate the die.

16. A punch press comprising a frame, means at the upper portion of the frame for removably supporting a punch, a ram mounted for reciprocal movement below the punch, a die carried by the ram and aligned with the punch, an electric motor, clutch means for drivinglyconnecting the ram to the motor, an electro-magnetic stripper plate having its lower face spaced upwardly from the lower terminal of the punch to facilitate guiding a piercing jig onto the lower end of the punch to align the blank with the punch, a normally open control circuit for the stripper plate become energized to firmly hold the jig in alignment with the punch, energization of the control circuit simultaneously rendering the clutch means operative to drive the ram.

17. A punch press comprising: a frame, means at the upper portion of the frame for removably supporting a punch, a ram mounted for reciprocal movement below the punch, a die carried by the ram and aligned with the punch, an electric motor, clutch means for drivingly connecting the ram to the motor, an electro-magnetic stripper plate having its lower face spaced upwardly from the lower terminal of the punch whereby an operator may readily and conveniently guide a piercing jig onto the lower end of the punch to align the blank with the punch, a normally open control circuit for the'stripper plate connected to a source of power, a pair of spaced contacts in the control circuit positioned to be engaged by the piercing jig, when the jig is moved into alignment with the punch, whereby the jig will bridge said contacts and thereby close the control circuit and cause the stripper plate to,

operation, energization of the control circuit simultaneously rendering the clutch means opera- 7 tive to drive the ram, and means for rendering iii the clutch means inoperative, immediately following the blank-piercing operation.

18. A punch press comprising a ram having a punch mounted in the upper portion thereof, a guide in the lower portion of the frame, a ram I mounted for reciprocal movement in said guide,

a die carried by the ram, a motor foroperating the ram, an electric supply circuit for said motor, an electro-magnetic stripper plate having its lower face spaced upwardly from the lower end of the punch and having a re-entrant notch in its periphery whereby an operator may conveniently and quickly guide a piercing jig onto the punch to accurately align the blank with the punch and die, an electric'control circuit for the stripper plate and clutch means, and a normally operable safety device so associated with the motor circuit and the control circuit that it must be moved into operative position by the operator, before said circuits can be closed to start the press.

19. A punch press comprising a ram having a punch fixedly mounted therein, a guide in the frame aligned with the punch, a ram mounted for reciprocal movement in said guide, a die carried by the ram, a motor having a supply circuit provided with a cutout switch, a clutch for drivingly connecting the motor to the ram, an electro-magnetic stripper plate having a re-entrant notch in its periphery whereby an opera- I tor may conveniently guide a piercing jig onto the punch to accurately align the blank with the punch and die, an electric control circuit for the clutch and stripper plate, a cutout switch in the control circuit, and a safety device comprising a pivoted member adapted to be positioned to prevent an operator from inserting a hand between the punch and die, when inserting the piercing jig therebetween, said pivoted member having operative connections with the motor circuit cutout switch and the switch in the control circuit, whereby when said member is in inoperative position, the motor cannot be started to drive the ram.

20. A punch press comprising a frame, means in said frame for removably supporting a punch.

a ram mounted for reciprocal movement in the frame, a die carried by the ram and aligned with the punch, a motor for driving the ram, an electric supply circuit for the motor comprising a cutout switch, clutch mtans for drivingly connecting the motor to the ram, an'electro-magnetic stripper plate, a normally open control cir-s cuit for the stripper plate connected to a source of power independent of the motor supply cirmally spaced from the die to-permit' insertion of the work between the die and punch, and a knockout pin slidably mounted over the punch and arranged to be manually actuated to quickly remove the punch from its supporting means, to permit another punch to be substituted therefor.

22. A punch press comprising a frame include ing a bed plate having a guide therein, a ram mounted in the guide operating means for the cuit, spaced contacts in the control circuit 10 ram, a cushion device mounted in the upper poradapted to be bridged by a piercing jig, subsequent-to the punch entering one of the guide ergize the stripper plate and to render the clutch 3 means operative to drive the ram, a circuit breaker in the control circuit for temporarily opening said circuit immediately following the blank-piercing operation, and a manually option of the frame and carrying a stripper plate, a tubular stem axially mounted in the cushion device and having a punch-holder cage secured to its lower end, said cage having a socket there- 5 in for receiving the shank of a punch, a springactuated ball mounted in a wall of said socket and engageable with a recess in the shank of the punch, thereby to secure the punch in said socket, means whereby said spring-actuated ball erable safety device operatively connected to the 20 may be moved out of engagement with the shank motor cutout switch in such fashion that said safety device must be moved into operative position by the operator, before the motor can be started to drive the clutch means.

of the punch, and a knock-out pin mounted in said tubular stem and having its lower end arranged to engage the end of the punch, and the upper end of the knock-out pin projecting-above 21. A punch press comprising a frame includthe end of said stem whereby. the knock-out pin the die in operative relation thereto and normay be conveniently actuated to eject the punch from the socket, when the spring-actuated retaining ball is in inoperative position.

LEONARD E. ASKE.

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