US1001606A - Automatic pneumatic feed for punch-presses. - Google Patents

Description

c. BAUMGARTNER.

AUTOMATIC PNEUMATIC FEED FOR PUNCH PRESSBS. APPLICATION FILED JAN. 30, 1908.

1,001,606, Patented Aug. 29, 1911.

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G. BAUMGARTNER.

AUTOMATIC PNEUMATIC FEED FOR PUNCH PRBSSES.

APPLIOATION FILED JAN.30,1908.

1,001,606. Patented Aug. 29, 1911.

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l u w flanradBaum art/vert- G. BAUMGARTNBR. AUTOMATIC PNEUMATIC FEED FOR PUNCH PRESSES.

APPLICATION FILED JAN. 30, 1908.

1,001,606 Patented Aug. 29, 1911.

3 SHEETS-SIIEET 3.

Witnesses: 815 1 1 l '1" Inventor.-

ioLuMmA PLANDCIRAPII c0. WASHINGTON, n. c.

tlNlTFill OFFICE.

CONRAD BAUMGARTNER, OF SCHENECTADY, NEW YORK, ASSIGNOR TO GENERAL ELECTRIC COMPANY, A CORPORATION OF NEW YORK.

AUTOMATIC PNEUMATIC FEED FOR PUNCH-PRESSES.

To all whom it may concern:

Be it known that I, CONRAD BAUMGART- NEH, a citizen of the United States, residing at Schenectady, in the county of Schenectady and State of New York, have invented certain new and useful Improvements in Autrr matic Pneumatic Feeds for Punel1Presses, of which the following is a specification.

This invention relates to devices for automaticall y feeding material to a machine, and its special object is to feed sheet metal to a punching press, although applicable to a wider range of uses. For the sake of simplieity, however, I shall describe it as applied to a sheet metal punching press. In feeding the sheets of metal to such a 11121 chine by hand, there must always be more or less waste, owing to the impossibility of moving the sheet forward exactly the same distance for each operation of the dies. Hand feeding is, moreover, liable to be slow, so that there is a loss of time in addition to the waste of material. In modern shop p notice, the operations are conducted on such a large scale that the small leaks are well worth looking after, and the object of my invention is to obviate the loss of stock and the time above noted, by providing a feeding mechanism which automatically advances the sheet of metal exactly the right distance at each stroke of the press to enable the dies to make a perfect punching without wasting more than a minimum of stock between two punchings. The mechanisu'i also works rapidly and constantly.

in case there is not enough stock left at the end of a sheet to make a perfect punching, the mechanism automatically makes a longer stroke, so as to pass this insullicieut portion beyond the dies and permit the end of a new sheet to he brought under them. Other details of operation will be brought out in the following detailed description.

The mechanism which forms the subjectmatter of this application comprises one or more pistons operated by fluid pressure in a suitable cylinder, a rod reciprocated by said piston or pistons, gripped fingers carried by said rod for seizing the edges of the Specification of Letters Patent.

Application filed January 30, 1908.

Patented Aug. 29, 1911.

Serial No. 413,371.

sheet of metal, and valve mechanism for admitting fluid pressure to said cylinder and exhausting it therefrom at the proper times in the operation of the press; it being understood of course that the sheet metal is advanced by the feeiling mechanism between the strokes of the dies.

In the accompanying drawings, Figure 1 is a side elevation of a punching press equipped with my improved automatic pneumatic feed; Fig. 2 is a longitudinal section of the cylinder and its pistons; Fig. 3 is a front elevation of the valve with its cover removed; Fig. 4.- is a cross section of said valve, complete; Fig. 5 is a perspective view of the wear plate in said valve; Fig. 6 is a perspective view of the valve proper; Fig. 7 is a sectional view of the clutch for holding the stop plug in place; Fig. 8 is a perspective view of the check valve and its controlling handles; Fig. 9 is a side elevation of the clutch-operating devices; Fig. 10 is a front elevation of the same: Fig. 11 is a front elevation of the rear grippers; Fig. 12 is a sectional elevation of the front gripper; Fig. 13 is a sectional elevation of one of the rear grippers; and Fig. 14 is a perspective view of the front gripper and the stop pin.

Attached to the frame 1 of the punching press is a horizontal cylinder 2 whose axis is parallel with the line of the feed. Stout guides 3 are secured to the frame parallel with the cylinder, and on these guides are mounted frames extending transversely of the line of feed and secured to the opposite ends of the piston rod .1: which runs through the cylinder 2 and 'zarries the two pistons 5 (3. These pistons are located on opposite sides of a stationary partition or internal head 7, secured in the cylinder about midway between its ends, and containing a central aperture for the piston rod, which has a sliding fit therein. 13y admitting fluid pressure into the cylinder on opposite sides of the partition or head 7, alternately, and between said head and the pistons, the latter and the piston rod to which they are attached, will be moved to and fro, causing the transverse frames to slide back and forth on the guides. These frames carry the grippers which seize the sheet. metal and feed it to the dies.

I will first describe in detail the cylinder and its appurtenances. Said cylinder is preferably provided with a bushing 8, which projects beyond the ends of the cylinder and receives at one end a screw-threaded sleeve 9 abutting against the adjacent end of the cylinder. At the other end, the bushing receives a union 10 which is screw-threaded thereon and retains in place a screw-threaded sleeve 11 rotatable on said bushing and meshing with screw-threads on the interior.

of a circular frame 12 which has an eye 13 clamped by a bolt 14 on the guide 3. A lock-nut 15 on the threaded sleeve 11 presses against one end of said circular frame. In the walls of the frame 12 are slots 16 through which extend latches 17 pivoted to said frame at 18 and urged inwardly by leaf springs 19. These latches serve to lock in place, in this end of the bushing, a tubular plug 20 concentric with the piston rod 4, which acts as a stop to limit the movement of the piston 6 and the piston rod. The plug is preferably adjustable along the piston rod, as for instance by means of a. nut 21 and lock nut 22 screwed upon the exterior of said plug; the nut 21 containing a circumferential groove 23 in which the latches 17 engage. A further function of this plug will be described later.

Fluid pressure, preferably compressed air, is supplied to the cylinder 2 through a pipe 24 which communicates with a valve chest 25 through a suitable shut-off cook 26. The air must be maintained at or above a predetermined minimum pressure to effect a proper operation of the mechanism, and in case it falls below this minimum a signal is arranged to warn the attendant, areferably a whistle 27. The valve chest contains a cylindrical chamber 28, closed by a head 29 and containing a circular disk valve 30 which is mounted on or formed integral with a shaft 31 journaled in the back wall and the head of the chest. A spring 32 encircles the shaft inside the chest and presses the valve against a stationary plate 33 of brass or other suitable material serving as a. wear plate and also as a seat for the valve. In the plate 33 are three ports, 34 36, the first communicating with a pipe 37, leading to the admission port 38 near the head 7 in the cylinder 2; the second communicating with a similar pipe 39 leading to the port 40 in said cylinder, and the third connecting with an exhaust pipe 41. In the valve disk are two through ports 42 43 arranged to be brought in line with the ports 34 35 by oscillating the shaft 31. Between these ports 42 43 is a recess 44 adapted to connect either of the ports 34, 35 with the exhaust port 36. The valve 30 also contains a. recess preferably composed of three circular depressions 45 connected by grooves 46, and communicating with the chamber 28 by one or more holes 47. In the face of the seat 33 are formed two grooves 48 which arebrought alternately into communication with the recesses 45 at the ends of the oscillations of the valve. These recesses and grooves admit compressed air between the valve and its seat to serve as a lubricant. The valve is oscillated by means of a crank arm 49 on the shaft 31 outside of the valve chest. A pitman 50 connects this crank with a. wrist pin 51 on the main shaft 52 of the press. The pitman is preferably connected with the crank by a lost-motion device in order to produce a dwell at each end of the stroke of the valve. In Fig. 1 the crank is shown as pivotally connected to a sleeve 53 through which slides a nut 54 adjustable on the pitman and having at each end a flange which strikes the sleeve and causes the crank to move, the space between the flanges being greater than the length of the sleeve.

In each of the pipes 37 39 is a check valve 57 opening toward the cylinder 2. In order to permit the escape of the air which is admitted to the cylinder through these pipes, an exhaust port 58 is located a little distance away from the head 7 in each end of the cylinder and a branch pipe 59 is shunted around the check valve 57 from each of the pipes 37 39 to said port. In each branch pipe is a check valve 60 opening away from the cylinder 2.

When the parts are in the positions shown in Figs. 1, 2 and 3, the air will pass through the ports 42, 34, the pipe 37 and the port 38 to the left hand end of the cylinder as shown in Figs. 1 and 2, forcing the piston 5 to the left. Meanwhile the exhaust port 58 in the other end of the cylinder has been put in communication with the escape pipe 41 througl'i the pipe 39, the port 35, the recess 44 and the port 36. When the piston 6 moves over the port 58 to the position shown in Fig. 2, it cuts ofi the exhaust through said port, but the air imprisoned between said piston and the head 7 can escape slowly through a pet cock 61 on the pipe 39 below the check valve 57, thus causing a cushioning effect on said piston.

Having thus ascertained how the pistons are caused to reciprocate the rod 4 in synchronism with the rotation of the main shaft of the press, and at the times when the wrist pin on said shaft is passing its upper and lower dead points, I will now take up the grippers which seize and carry place on said tubes. The casting carries an overhanging upper jaw (35, and its lower part contains a cylinder in which is located a piston or other movable abutment (if). on which is supported a lower jaw (37. Springs are arranged to urge said lower aw open,

as for instance the springs (38 engaging with the headed pins (3!) which extend from said jaw down into sockets in the casting. The lower end of the cylinder is connected by a pipe T0 with the compressed air supply, so that when air is admitted under the piston or other abutment the lower jaw will be raised and the two jaws will grip the edge of the sheet 71 of metal, which is to be fed to the dies.

The admission of air to the abutments of the grippers is preferably controlled by the main valve in the following manner. From the pipe 3?, which supplies air to the piston 5 which effects the forward feed of the sheet, branch pipe 72 leads through a stop valve 73 to a pipe 74 from the ends of which flexible hose-pipes '75 run to the pipes 70. The instant air is admitted to the pipe 37, it not only causes the feeding stroke of the piston rod t, but it also closes the grippers on the edges of the sheet metal, so that the latter is carried forward with the rod. There are preferably three grippers; one at the front and two at the rear of the dies, the latter being on opposite sides of the sheet, but both carried on the same frame; as shown in Fig. 11. This frame also carries a transverse rock shaft 76 to which are secured resilient fingers 77 resting on the upper surface of the sheet metal. At one end of the shaft is a rock arm 78 adapted to come in contact with a stationary tappet 7.), which is adj ustably secured by the screw 80 to the frame of the press. hen this shaft is rocked by the tappet the fingers press down on the blanks punched from the sheet and force them to fall into the recep tacle provided for that purpose. This prevents any blanks from sticking in the sheets and going into the waste.

Tn order to properly position the sheets when they are fed into the machine, and in sure that they shall be presented to the dies in such a way that the first blank punched will come close to the end of the sheet, a stop pin 81 provided in the front gripper. This pin has a base 82 containing a slot to receive a clamping screw 83 so that the pin can be adj nsted for different kinds of work. lVhen the lower aw of the gripper rises to seize the sheet, 1t lifts said sheet above said pin, so that the pin offers no obstruclimr to the onward feed of the sheet, in subsequent operations.

lt frequently happens that the sheets of metal are not quite long enough to provide for a punching close to the rear end thereof, but a certain amount of waste is necessary. In order to prevent the making of imperfect punchings at the ends of such sheets, and at the same time insure a sufficient forward feed of the incoming fresh sheet to bring it fully under the dies, it is necessary to provide for a stroke of the feeding mechanism long enough to make up for the additional amount of waste in the length of the old shtaet. To cause this to take place automatically, l uulatch the stop plug .tthso that at the next back stroke of the piston red the air n'essure will force the plug out of the cylinder 2 until it is stopped by the collar St on said rod; said collar being set at the same distance from the outer end of the plug as the space between the head T and the piston lnasmuch as the rod is not checked by the plug, it will move ba('-kward until the piston 5 cushions against the head 7. The extent of this movement can be adjusted by adjusting the piston 5 along the red; the hub of the piston being preferably screw-threaded to mesh with screw threads on the rod, and provided with a tapering end on which a clamping nut 85 is placed.

In order to unlatch the plug, the latch levers are pivotally connected at their free ends with movable abutments, such as pistons 86 in a cylinder 87. \Vhen compressed air is admitted between said pistons they will be forced apart and the latches will be withdrawn from the circumferential groove 23 in the nut .31 on the plug. The air is led to this cylinder 87 by a hose RH branching off from the main air pipe l t at a point above the valve chest 25, and being itself controlled by a valve 89, which is held nor mally closed by a spring {)0 bearing on its handle 9'1. r'tdjacent to this handle is mounted a rock shaft 92 carrying a finger 93 which lies under said handle. The shaft also has a rock arm h t on which is secured a bar 95. A longitudinal slot 9t) in the bar and a clamping screw S)? enable the bar to be properly adjusted. At the lower end of the bar there is pivoted a long hook 98 which rests on the surface of the metal sheet 77. The hook extends toward the dies of the press, and its other end, on the opposite side of the pivot, is connected by a light spring 95) with a stud [00 on the upper end of the bar. This spring urges the hook downwardly upon the surface of the metal sheet. As a new sheet of metal is started along through the press its end encounters and engages with this hook, carrying it toward the dies and swinging the bar to an upright position as shown by the dotted lines in Fig. 9. In this movement, the screw 101 carried in a lug 102 011 the bar comes in contact with the hook and causes its end to lift away from the sheet of metal so that said sheet is free to pass on through the press. In this dotted line position of the bar the finger 93 on the rock shaft 92 will have raised the handle of the valve 89 against the tension of the spring 90, thereby opening said valve and admitting compressed air to the cylinder 87. The movable abutments 80 are thereby forced apart, and the latches are withdrawn from the groove in the nut 22 on the plu 20. On the next backward stroke of the piston rod 4, the piston G will strike the plug and carry it out of the cylinder 2 to the position shown in Fig. 1, at which point the piston 5 comes in contact with the stationary head 7. The abnormal length of the backward stroke thus permitted, enables the rear grippers to take hold of the sheet of metal 77 far enough back of their usual point of operation to enable them to pull the rear end of the sheet being operated on completely past the dies, so that there will be no danger of an imperfect punching being made in the insufficient stock that remains at the end of the sheet. At the same time, the front grippers carry the fresh sheet forward such an amount as to insure its end passing fully beyond the dies at the next feeding stroke, so that the first punching made in that sheet will be sure to come entirely within it.

The'action of the valve 89 is only mementary, because the spring 90 closes this valve as soon as the hook is raised out of engagement wit-h the end of the sheet. In closing the valve, the spring also acts to return the bar 95 to the position shown in full lines in Fig. 9, except that the hook will rest on the upper surface of the sheet passing under it, being ready to drop over the end of a new sheet, as shown. The extent of angular movement of the rock shaft, is limited by an arm 103 thereon, which comes into contact with a detent stud on the frame of the press when the parts return to their normal. position. The movement of the valve which shuts off the air from the cylinder 8'? also serves to open an exhaust port from said cylinder, so that the springs 19 can return the latches to their locking position in the groove 23, when the plug is carried into the cylinder 2 by the feeding stroke of the piston red t. It will thus be understood that the operation of this part of the apparatus is intermittent, taking place only when a fresh sheet is fed into the press. The quantity of waste in any given sheet depends upon the size of the punching that is being cut therefrom, so that for each change in the dies the piston 5 must be adjusted to produce the proper length of abnormal stroke when the plug 20 is unlatched. The stop pin 81 must also be adjusted so that the entering end of the fresh sheet will be in proper relation to the dies.

The operation of the several parts of the machine has been described in connection with their construction, but it may be said by way of recapitulation that the sheets of sheet metal are automatically fed to the dies by the grippers 62 carried on the piston rod 4, which is reciprocated by the pistons 5 6 in the cylinder 2. Compressed air is admitted to the cylinder by an oscillatory valve 30 actuated by a crank 49 and a pit man or connecting rod 50 which has a certain amount of lost motion, so that the sheet is held firmly during the cutting stroke of the dies and until they have separated sutliciently to clear the sheet; after which the valve is moved and the open grippers are slid back to take a new hold on the edges of the sheet. Shortly after the upper die begins to descend the valve is reversed and the grippers close on the sheet and move it forward to present a fresh surface to the dies. The grippers are opened and closed by compressed air, and are controlled by the same valve which controls the air supply to the cylinder 2. The normal stroke of the grippers is just enough to enable each punching to come close to the one preceding it without undue waste. In case there is danger of an imperfect punching at the end of the sheet, the plug 20, which limits the feeding stroke of the grippers, is unlatched and the grippers are permitted to slide back an abnormal distance to give a longer feed and thereby cause the end of the old sheet to skip the dies. This is automatically effected by a hook adapted to engage with the entering end of a new sheet, said hook controlling an air valve which admits air to movable abutments by means of which the latches holding the plug are released, for that stroke. In case the attendant wishes to stop the feed at any time, he can shut off the supply of air to the grippers by means of the valve 73 in the pipe 72; said valve being held normally open by a spring 104, and provided with handles 105 located conveniently within reach of the attendant.

What I claim as new and desire to secure by Letters Patent of the United States, is,

1. The combination with a punching press, of pneumatic means for automatically gripping the sheet of metal to be fed to the dies, and pneumatic means for automatically advancing said gripping means to carry said sheet under said dies.

2. The combination with a punching press,

of a set of grippers to feed a sheet of metal to the dies of said press, a rod for actuating said grippers, and a movable abutment responsive to fluid pressure and connected with said rod.

wwwm 8. The combination with a punching press, of a set oil gi' ")pers to teed a sheet ot metal to the dies of said press, a rod tor actuating said grippers, a piston attached to said. rod, and a cylinder containing said piston.

4t. Thecombination with a punching press. of a set o't gri mers to :l'eed a sheet ot metal to the dies oi? said press, a rod tor actuating said grippers, pistons attached to said, rod, a cylinder containing said pistons, and a valve controlling the admission ot lluid pressure to said cyliniler.

5. The combination with a. punching press of a set ol grippers to teed a sheet of metal to the dies of said press, a rod tor actuating said grippers, pistons attached to said rod, a cylii'ider containing said pistons, a valve controlling the admission of [luid pressure to said cylinder, and means tor operating said valve in synchron ism with the dies.

5. The combination with a punching press. ot a cylii'nler parallel with the line ot feed to the dies of said. press, pistons in said cylinder, a piston rod, grippers adapted to seize the edges of the sheet and mounted on said rod, moyable abutmenls lor operating said grippers, and a Valve controlling the admission ot fluid pressure to said cylinder and to said abutnients.

7. The combination witha punching press, ot a cylinder parallel with the line of feed to the dies of said press, a stationary head in said cylinder, a piston rod passing through said cylinder andv head, pistons on said rod on opposite sides of said head, a valve tor controlling the [low of tluid pressure to said cylinder on opposite sides of said head, and grippers carried by said piston rod.

8. The combination with a punching press, of pneumatic means for feeding a sheet of metal to the dies of said. press, and means for antomatically varying the stroke of said feeding means.

t). The combination with a punching press, of pneumatic means for feeding a sheetoi? metal to the dies of said press, and means whereby an entering sheet is caused to Vary the stroke of the 'teediug means, in order to avoid imperfect punchings.

10. The con'ibination with a punching press, of pneumatic means tor feeding a sheet of metal to the dies of said press, a stop for determining the stroke of said itecding means, and means for automatically withdrawing said stop when a new sheet entors the press.

ill. The con'ibination with a punching press, of pneumatic means for feeding a sheet of metal to the dies of said press, an adjustable stop for limiting the normal stroke of said feeding means, and means for aijitomatieally withdrawing said stop when a new sheet enters the press.

12. The combination with a punching press, of feeding means comprising a cylinder, a stationary head therein, a piston rod, pistons thereon on opposite sides of said head, and an adjustable plug in one end oi. said cylinder serving to limit the movement ot said rod and pistons.

l3. The combination with a punching press, ol 'Iecding means comprising a cylinder, a stationary head therein, a piston rod. pistons thereon on opposite sides o'l said head, an adjustable plug in one end of said cylinder serving to limit the movement of said rod and pistons, and means for automatically releasing said plug to permit said rod to make an abnormal stroke.

l t. The eombimltion with a punching press, of feeding means eonu'lrising a cylin der, a stationary head therein, a piston rod, pistons thereon on opposite sides ot said head. one of said pistons being adjustable lengthwise o'l' said red, a plug cooperating with the other piston to limit the normal stroke ot the rod, and means tor automatically witlnlrawing said plug to permit the adjustable piston to govern the stroke,

'15. The combination with a punching press, of feeding means comprising a cylinder, a piston rod and piston therein, a plug in one end thereot. a clutch for holding said plug in place, and means for autoimitically releasing said clutch.

to. The combination with a punching press. of "feeding means comprising a cylinder, a piston rod and piston therein, a tubular plug in one end thereof, a latch engag ing with said plug. a movable element adapted. to be engaged by a sheet of metal entering the. press, and connections between said element and the latch for disengaging the latter From the plug. i

1.7. The combination with a punching press, of feeding means comprising a cylinder. :1 piston rod and piston therein, a tubular plug in one end thereof, a latch engaging with said plug, a movable element adapted to be engaged by a sheet of metal entering the press. connections between said element and the latch tor i liscngaging the latter from the plug, said connections comprising a movable abutment responsive to tluid pressure, and a valve operated by said movable element and controlling a supply o't fluid pressure to said abutment.

'18. The combination with a punching press. of feeding means comprising a cylinder, a piston rod and piston therein, a tubular plug in one end thereof, a latch engaging with said plug, a hook adapted to be engaged by the end ot a sheet of metal entering the press, means for disengaging said hook after said sheet has moved a short distance. and fluid pressure connecting mechanism between said hook and said latch operating to release the plug when said hook is actuated.

19. The combination with a punching press, of pneumatic feeding means for the In Witness whereof, I have hereunto set sheet metal, comprising a reciprocable rod, my hand this 28th day of January, 1908.

pistons for actuating said rod b fluid presi sure, grippers mounted on said od and 0p- CONRAD BAUMGARTNER' erated by fluid pressure, and means for pre- Vitnesses:

Venting the operation of the grippers With- BENJAMIN B. HULL,

out stopping the reciprocation 01": said rod. HELEN ORFORD.

Copies of this patent may be obtained for five cents each, by addressing the Commissioner of Patents, Washington, D. C.

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