US2803335A - Air operated slide feed - Google Patents

Description

W. P. POWERS AIR OPERATED SLIDE FEED Aug. 2o, 1957 5 Sheets-Sheet l Filed Feb. 6 1956 BY www@ Aug. 20, 1957 w. P. POWERS AIR OPERATED SLIDE FEED 5 Sheets-Sheet 2 Filed Feb. 6, 1956 Aug, 2o, 1957 w P, POWERS 2,803,335

AIR OPERATED SLIDE FEED 5 Sheets-Sheet I5 Filed. Feb. e, 195e' Alig- 20, 1957 W. P. lPOWERS 2,803,335

' A AIR OPERATED SLIDE FEED l Filed Feb. 6, 1956 5 Sheets-Sheet 4 A l IN1/EN TOR. /Zu v'E/P /fD/oawws BY v w. P. POWERS l AIR OPERATED SLIDE FEED Aug.r 20,V 1957 5 Sheets-Sheet 5 Filed Feb. 6, 1956 INVENTOR.

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United States Patent 2,803,335 Patented Aug. 20, 1957 hee AIR OPERATED SLIDE FEED Walter Palmer Powers, Spring Lake, N. 3., assignor to C. Todd, as trustee Application February 6, 1956, Serial No. 563,662

11 Claims. (Cl. 203-159) The invention herein disclosed relates to slide feeds.

The general objects of the invention are to provide a slide feed operable by compressed air which will be economical in the use of such power and which will be capable of high speed, accurate feeding operations.

Special objects of the invention are to provide such mechanism in a practical, low cost construction made up of few simple parts.

Other desirable objects attained by the invention and the novel features through which all such purposes are accomplished, are set forth or will appear in the course of the following specication.

The drawings accompanying and forming part of the vspecification illustrate present commercial embodiments f the invention. Structure and arrangement, however, may vary from the immediate illustration, all within the true intent and scope of the invention as hereinafter defined and claimed.

Fig. 1 in the drawings is a schematic part sectional view illustrating the slide block 0n the return or recovery stroke of the differential piston with the gripper in open position and the check closed, holding the stock in the position advanced by the gripper;

Fig. 2 is a similar View showing the slide block up against the back stop at the end of the recovery stroke and with the differential piston starting forward, opening up pressure to the small, gripper closing cylinder in the feed block, the gripper about to close and the check about to open;

Fig. 3 is a broken sectional view showing relation of parts at the end of the forward, feed stroke, with the block up against the front stop and with gripper and check both closed.

Fig. 4 is a similar View of the parts at start of the back stroke, with gripper open and check closed;

Figs. 5 and 6 are fragmentary Views of the gripper showing it in open and closed positions;

Fig. 7 is a broken front elevation of one of the complete units;

Fig. 8 is a broken top plan view of the same;

Fig. 9 is a cross-sectional view on substantially the plane of line 9 9 of Fig. 8;

Fig. 10 is a diagrammatic illustration of a semi-automatic, as distinguished from a fully automatic form of the invention, as first illustrated.

In the general view, Fig. 1, the slide or feed block is shown actuated by a piston 16 operating in cylinder 17.

The piston rod 18 is relatively large in diameter to reduce the effective area of the rod side of the piston, thus to provide a differential piston effect. In the illustration the area at the rod side of the piston may be about half that at the other side, providing a differential of about two to one.

With this differential relation, assuming for example, a pressure of 100 pounds per square inch acting on both sides of the piston, pressure at the full' area side will overcome pressure at the lesser area side to advance the piston for a feed stroke, and on release of pressure at the full area side the pressure at the lesser area side will be effective to return the piston.

This relation, therefore, makes it possible to leave pressure on the lesser area side for the vreturn or recovery strokes and without exhausting this pressure, rely on the maximum area pressure at the opposite side to effect working strokes of the piston, the air in the return chamber being pushed back into the line to be reused.

This feature of the invention accomplishes a saving in compressed air since the only air that needs to be exhausted is that acting on the working side of the piston.

The connections required for this diiferential piston operation may be such as shown in Fig. 1, involving a compressed air supply line 19, 19a which may have the more or less usual air line filter 20, pressure regulator 21 and lubricator 22 therein, extending to the larger piston area working end of the cylinder and an open branch 23 extending to the lesser piston area end of the cylinder, with a 4-way pilot valve 24 interposed in the supply line and controlling admission and exhaust to and from the working end of the cylinder.

Gperation of the pilot valve is controlled in the illustration by a front Z-way limit valve 25 operated by the slide block at the end of its feed stroke and a back 2-way limit valve 26 actuated by the slide block at the end of its return or recovery stroke. These two valves are shown connected by pipes 27, 23 with the spring return pilot cylinder 29 at one end of the pilot valve, and the back stop limit valve is shown connected by pipe 39 with the open branch 23 of the supply line.

From the opposite end of the 4-way pilot valve a connection 31 is shown running to the stock check 32 and which may be extended as shown at 33 to the non-repeat press control which operates the press or other machine which the slide feed is supplying with stock.

The stock check is shown as a plunger 34 cooperating with anvil 35 and actuated by a spring retracted piston 36 subjected to pressure from the line 31.

With the connections described the front limit valve 25 will be actuated by the slide block at the end of the forward feed stroke to operate the 4-way valve to admit air line pressure, as indicated by cross arrow 37, to the stock check and to the non-repeat press control which operates the press or other machine. Also, through control connections 27, 2S, the 4-way valve is actuated as indicated by cross arrow 3S to exhaust pressure from line 19a extending to the working end of the cylinder, through the exhaust connection 39.

At the `end of the recovery stroke the slide block actuates the back limit valve 26, supplied with pressure through line 39, to reverse the pilot valve to admit presI sure from the supply main 19, as indicated by arrow 40, to the continuation 19a of the supply line to the working end of the cylinder, thus to start the piston on the feed stroke.

To assu-re rm gripping of the stock before the slide block starts the feed movement, a lost motion connection is provided between the piston and block and the taking up -of this lost motion is utilized to effect the closing of the gripper on the stock.

In the illustration the lost motion coupling comprises a reduced stern 41 on the end of the piston rod sliding in a bore 42 in the end of the block 'and carrying an abutment head 43 inside the 'block operating freely in a cylindrical chamber 44 containing the piston 45 for operating the gripper.

The gripper is shown .as a cam 46 carried by la rock :shaft 47 journaled in the feed block, in cooperative relation to an anvil 48, said shaft carrying a lever arm 49 having a rocking connection 5@ with the stem yor rod portion 51 of the piston and a spring 52 acting on lever 49 to return the parts to the gripper-open position.

rPressure for 'actuating .the small gripper closing piston is supplied in the illustration from the feed line 23 for the return stroke of the main piston, by constructing the piston Irod 18 as a hollow member and with an entrance 53 for such air pressure near the piston end, and by constructing the coupling stem 41 as a valve element having a passage 54 into the end of the same, terminating in a circumferential valve port 55 closed by the surrounding bearing 42 when retracted as in Fig. 1, but open to the gripper closing cylinder 44 when projected as in Fig. 2.

Additionally the valve stem is shown as having fa pressure relief groove 56 in the side of the same extending back from the abutment head 43 a distance sufficient to be uncovered in the fully retracted position, Fig. l, and to be covered and closed by the surrounding bearing when the valve lstem is projected as in Fig. 2.

The gripper may be* constructed as shown in Figs. and 6, with la spring pressure plate 57 supported at 58 between the closing cam 46 and the anvil 48 to provide firm gripping engagement with the stock 59,

Figs. 7, 8 and 9 show the slide 'block 15 operating on guide rods 69, 61 carried by a base or frame 62 which may be constructed as indicated at 63 for attachment to or mounting on the bed of a press or other such machine.

In these views the back stop 64 for the slide block is shown as a stop screw -adjustably mounted in a bracket 65 adjustably secured on the guide rods.

Figs. 5, 6, 7 and 8 further show how the unit may be lconstructed for feeding in either direction, the gripper closing cam 46 being shown as symmetrical and secured by bolts 66 on the end of the rock shaft so that it may be reversed, the pressure pad 57 secured by screws 67 to one or the other of the projections 68, 69 at opposite sides of the shaft, and the anvil 48 secured by screws 70 at one or the opposite side of the center support 71.

While theV present invention renders it unnecessary ordinarily to provide the slide block with braking means, it is considered that some such'means may be used if found necessary or desirable.

A suitable on-and-off valve 72 maybe provided in the air line and used for starting and stopping the machine or, if desired, for speeding up or slowing down operation vand for inching the slide block one way or the other on the guide rods. This may be a C. B. Hunt #700 3-way shut-oft` valve. Also or instead of using valve 72 as a throttle to control speed of operation, the pressure regulator 21 may be adjusted to effect speed control.

The lter 20, pressure regulator 21 and lubricator 22 may be of conventional design Iand similarly, the pilot operated 4-way valve 24 and limit valves 25 and 26 may be of conventional design. At present a Schrader #33211y 4-way control valve is used and for limit valves Schrader #325GB flow control valves zare employed.

Operation In the recovery stroke indicated in Fig. 1, full line pressure on the lesser side of the differential piston 16, with pressure released at the opposite side, effects movement toward the left with the lost motion connection at 41 with the slide block extended, closing on" entry of air =to the gripper cylinder 44 at port 55, and air released from 44 at -port 56, with the gripper rocked to open position and so held by spring 52.

vOn reaching the back stop at the end of recovery stroke the limit switch 26 is actuated by the slide block to effect operation of 4-way valve 24 which opens line pressure on the larger diameter side -of the differential piston, indicated by the heavy -arrow 40. This pressure on the full diameter side of the piston 4overcomes the same line pressure on the opposite, lesser side of the piston, starting the piston toward the right as in Fig. 2 to open valve port 55 and thereby admit air line pressure to the gripper closing piston 45.

As a part of or following this gripper closing action of the 4-way control valve, pressure is released lOm the stock check cylinder 32, as indicated by :arrow 73, Fig. l. Y

. Fig. 2 shows the gripper about to close on the stock and the check closed but about to open as the slide block begins its forward stroke.

Forward movement is imparted to the block by the shoulder 74 at the end of the piston rod coming into abutting engagement with the block, as indicated in Fig. 3. This View shows the condition of parts yas the block digages the front stop land operates the front limit valve 25, Fig. 1, which in turn effects `operation of the 4-way control valve 24 to apply line pressure as indicated by arrow 37 to close the check and to exhaust pressurey from the working side of the piston, as indicated by arrow 38.

Air line pressure on the lesser side of the piston then 'becomes effective to start the differential piston back on the return stroke so that as shown in Fig. 4, with the advanced stock held by the check, the start of the ret-urn movement will first close port 55 4to shutoff supply of air to the gripper cylinder 44 and then vent pressure in `that cylinder through groove 56 in the valve stem, enabling spring 52 to open and hold the gripper open for lthe full return stroke.

For full automatic operation the line 33, Fig. 1, is extended to the non-repeat press control so that when the front limit valve 25 is actuated by the slide block, air line pressure is put on both the stock check and the nonrepeat press control. If, then, the feed is fast enough the press will run continuously. Otherwise it will run singly tripping but entirely automatically.

In the semi-automatic embodiment of the invention illustrated in Fig. 10, the press is manually started. A cam 75 on the press operates a limit valve 26a which shifts the 4-way valve to effect a forward, feed stroke. At the end of this stroke a front limit valve 25a reverses the 4-way valve to close the stock check and openthe gripper.

In this case the feed cycling must be faster than the press rotation if continuous operation is desired. Otherwise only single tripping is possible.

The lost motion connection between operating piston and slide block, effecting operation of the valve for admitting pressure to and exhausting it from the gripper closing cylinder, provides a time interval at each end of the block travel permitting closing of the gripper before the check releases hold on the stock and closing of the check before the gripper releases its hold. ,This enables, if desired, actual overlap so that stock'will be held under control at all times, assuring uniform, accurate feed.

The moving parts can be made relatively light in weight, eliminating objectionable inertia effects and enabling fast operation. The only air exhausted, aside from the comparatively small amount used in the gripper closing cylinder, is that in back of the differential piston at the end of the feed stroke, so the machine is economical in the use of this power.

If for any reason it be found desirable to reciprocate the slide block without operating the gripper, this may be effected by closing off the passage in the valve stem as by means of a small closure screw set in the side of the valve stem intercepting the central passage therein, this screw normally being left open but ready to be closed any time for reciprocating the slide block without operating the gripper.

What is claimed is: Y

1. Air operated slide feed comprising the combination of reciprocating slide block, stock gripping means on said slide block, a cylinder on said block, a piston in said cylinder and connected to operate said gripping means, a stationary feed cylinder, a piston in said feed cylinder having a piston rod slidingly engaged in said slide block and extending into the cylinder on said slide block, said piston rod having spaced abutment shoulders engageable with the slide block to limit relative sliding movement of the piston rod and block in opposite directions and providing a lost motion connection from the piston rod for reciprocating the block in opposite directions, said piston rod having a passage open at one end to interior of the feed cylinder and terminating at the opposite end in an inlet port in the side of that portion of the same slidingly engaged in the said block and positioned to open into th cylinder on the slide block when the piston rod is slidably projected toward the slide block and to be closed by the surrounding wall portion of the block in which the slidable portion of the piston rod is enf'aged when the piston rod is slidingly withdrawn from the slide block to the extent of lost motion movement provided by said lost motion connection and said slidingly connected portion of the piston rod having an exhaust passage in the side of the inner end portion of the same positioned to be closed by said surrounding wall of the block when the piston rod is projected into the slide block cylinder and to open from said cylinder to atmosphere when the piston rod is slidingly retracted in respect to the slide block to the extent permitted by said lost motion connection.

2. The invention according to claim 1, in which the portion of the piston rod operating in the feed cylinder is of relatively large diameter, reducing the effective area at that side of the piston and a compressed air supply source having a constantly open connection with the feed cylinder at the lesser area side of the differential piston and a valve controlled connection with the feed cylinder at the opposite, larger area side of the differential piston.

3. The invention according to claim 1, with air supply connections to the feed cylinder at opposite sides of the piston operating therein, valve means interposed in said connections and means actuated by said slide block for controlling said valve means.

4. The invention according to claim l, with a stock check, pressure cylinder and piston for actuating the same andl compressed air connections to said feed cylinder and to said pressure cylinder of the stock check.

5. Air operated slide feed comprising the combination of reciprocating slide block, stock gripping means on said slide block, a cylinder on said block, a piston in said cylinder connected to operate said gripping means, a stationary feed cylinder, a piston in said feed cylinder having a lost motion connection with said slide block said lost motion connection including relatively movable flow controlling valve forming parts and fluid pressure connections to said cylinder on the slide block including said relatively movable valve forming parts, whereby action of said stock gripping means is controlled by operation of said llost motion connection between said feed cylinder piston and slide block.

6. Air operated slide feed comprising the combination of reciprocating slide block, stock gripping means on said slide block, a cylinder on said block, a piston in said cylinder connected to operate said gripping means, a stationary feed cylinder, a piston in said feed cylinder having a lost motion connection with said slide block said lost motion connection including relatively movable ow controlling valve forming parts and fluid pressure connections to said cylinder on the slide block including said relatively movable valve forming parts, whereby action of said stock gripping means is controlled by operation of said ylost motion connection between said feed cylinder piston and slide block, a stock check, a pressure cylinder and piston for operating said stock check and controlled fluid pressure connections to said stock check fluid pressure cylinder.

7. Air operated slide feed comprising the combination of reciprocating slide block, stock gripping means on said slide block, a cylinder on said block, a piston in said cylinder connected to operate said gripping means, a stationary feed cylinder, a piston in said feed cylinder, a lost motion connection between said feed cylinder piston and slide block, including relatively movable flow controlling valve forming parts, fluid pressure connections to said stock gripping means operating piston including said flow controlling valve forming parts operable by said lost motion connection, a stock check, a pressure cylinder and piston for operating said stock check and pressure fluid connections to said stock check fluid pressure cylinder and to said feed cylinder and to said valve forming parts for the stoel: gripping means.

8. The invention according to claim 7, in which the piston in the feed cylinder is a differential piston and in which the duid supply connections to the smaller area side of said piston are constantly open and the connections to the larger area side of said piston include valve means for admitting and exhausting Huid pressure to and from that side of the piston.

9. The invention according to claim 5, in which the feed cylinder piston is a differential piston and in which duid supply connections are provided to opposite ends of the feed cylinder, including a constantly open supply connection to the lesser area side of the differential piston and a connection to the larger area side of said piston with valve means for admitting pressure to and exhausting it from that side of the differential piston.

10. The invention according to claim 5, in which said gripping means includes a rocker having a stock gripping cam, a lever extending from said rocker and connected with said stock gripping means operating piston and spring means for shifting said rocker actuating lever in opposition to said piston.

1l. Air operated slide feed comprising the combination of reciprocating slide block, stock gripping means on said slide block, a stationary feed cylinder, a piston said feed cylinder, a piston rod connected with one side of said piston and of relatively large diameter, reducing the eective area of that side of the piston, a compressed air supply source having a constantly open connection with said feed cylinder at said lesser area side of the piston, a valve controlled connection with the feed cylinder at the opposite larger area side of the piston and means for effecting operation of said stock gripping means at the end of movement of the reciprocating slide block in opposite directions.

References Cited in the file of this patent UNiTED STATES PATENTS

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