US3580449A

US3580449A - Stock feed apparatus

Info

Publication number: US3580449A
Application number: US766757A
Authority: US
Inventors: Michael J Chaban Jr
Original assignee: Standard International Corp
Current assignee: Standard International Corp
Priority date: 1968-10-11
Filing date: 1968-10-11
Publication date: 1971-05-25
Anticipated expiration: 1988-05-25

Abstract

Stock-feeding apparatus of the intermittent reciprocating type having a simplified four-way valve for positive control of the sequencing of the apparatus. Particular features include a pressure-operated momentum-absorbing device and a practical simplified stock-release means.

Description

United States Patent '2 I66 245 243 w? I82 [56] References Cited UNITED STATES PATENTS 3,038,647 6/1962 Grimm 226/159 3,326,438 6/1967 Dickerman.... 226/150 3,429,493 2/1969 Lehmann 226/150 3,462,056 8/1969 Scribner 226/ 150 Primary Examiner-Richard A. Schacher Attorney-Joseph Weingarten ABSTRACT: Stock-feeding apparatus of the intermittent reciprocating type having a simplified four-way valve for positive control of the sequencing of the apparatus. Particular features include a pressure-operated momentum-absorbing device and a practical simplified stock-release means.

llllllhll'Ei- PATENTEUMAYZSIHYI 3580.449

SHEET 1 BF 4 INVENTOR MICHAEL J. CHABAN,JR.

AT'I ORNEYS PATENTED HAYZ 512m SHEET 3 BF 4 MICHAEL INVENTOR J. CHABAN, JF

ATTORNEYS PATENTEDMAY25|971 7 3580.449

SHEET U UF 4 I4 26 ll 222 234 FIG. 6 INVENTOR MICHAEL J- CHABAN, JR.

ATTORNEYS srocx FEED APPARATUS FIELD OF THE INVENTION This invention relates in general to automatic feeding apparatus of the intermittent reciprocating type for feeding elongated stock to a cyclically operating work machine and more particularly concerns a novel pneumatic mechanism which feeds increments of stock in a positive and reliable manner with highly accurate repetitiveness at a reduced noise level. A simplified means for releasing the stock speeds the loading and unloading of this stock-feeding apparatus.

DISCUSSION OF THE PRIOR ART Many manufacturing operations require intermittent feeding of strip material to a parent work machine such as a punch press which intermittently performs such operations as blank ing, cutting, punching and stamping. The length of material to be fed to the parent machine will vary with the type of operation being performed. The operation of the stock-feeding mechanism is controlled by the operation of the parent machine so that its speed of operation is in synchronism with the cyclic operation of the punch press. For economical reasons, it is desirable that the stock-feeding mechanism be able to operate reliably at least as fast as the maximum operating frequency of the parent machine.

Some presently available stock-feeding mechanisms have shown a tendency, when operating at a relatively high frequency, to allow a slight inertial sliding of the stock at the end of each feeding stroke due to the abrupt stop of the feeding mechanism. Furthermore, at high frequencies the intensity of the noise. generated by many of the prior stock-feeding mechanisms has been quite high and, with the already high noise level likely to exist in a machine shop, adds considerably to the discomfort of personnel in the area.

Wear of the fluid seals in some of the existing stock-feeding mechanisms has resulted in a reliability problem. Resilient rings have generally been used to provide seals between members which move relative to one another for the purpose of preventing leakage of the prime mover fluid. However, the wear of these seals caused by continued use of the stock feeder requires their relatively frequent replacement, resulting in uneconomical idleness of the parent machine each time replacement of these seals is necessary. Another problem present in many prior devices is that when the stock is initially loaded into the stock-feed mechanism or removed therefrom, it has been necessary to disconnect or turn off the source of power, usually by closing a valve in the incoming fluid or air line to the feeding mechanism. This, of course, decreases the productive time of the machinery while at the same time requiring significant manipulation by the operator. Another time-consuming operation which, in some of the present stock feeders, decreases the productivity of the parent machine is the adjustment required for varying the length of each feed stroke. Such existing stock-feeding mechanisms require stopping the work machine, loosening of one or more bolts on the feeding apparatus, moving a bracket which acts as a stop for the moving feed member and retightening the bolts. This only provides for major stepwise feed stroke adjustment, and another operation is required for minor adjustments between the major adjustment positions.

SUMMARY OF THE INVENTION Most existing stock-feeding mechanisms have one or more of the above-enumerated disadvantages. It is a primary object of this invention to provide an incremental stock feeder which permits the stock material to be changed or adjusted without disconnecting the power source, and which feeds predetermined lengths of stock to a work machine in a positive and accurate manner with a minimum of noise. Furthermore, the length of the feed stroke is continuously adjustable while the machine is operating.

Broadly speaking, the present invention concerns a fluidpressure-operated intermittent stock-feeding apparatus capable of operating reliably at high speeds with a relatively low air pressure input. The apparatus generally comprises a stationary body having stock-clamping means and a reciprocating feed head having stock-gripping means. Piston rods and pistons are fixed relative to .the stationary body with the feed head sleeved onto them. A control valve is mounted in the stationary body and controls the supply of fluid pressure to the various parts of the apparatus.

The stock-feeding apparatus is constructed with novel seals which are a combination of self-lubricating plastic glide rings enclosing conventional resilient O-rings, customarily made of neoprene. The glide rings provide the bearing surfaces for those seals which are subject to substantial sliding contact. These combination seals result in substantially increased reliability and operating life of the apparatus. A braking piston operated by fluid pressure directed by the control valve has a rod which extends outwardlyfrom the stationary body and is adapted to be contacted by the feed head near the end of the feed stroke, thereby absorbing most of the momentum of the feed head over a short distance. This energy-absorbing means essentially eliminates the chance for inertial movement of the stock at the end of each feed stroke. The control valve embodied in this invention is a four-way valve which alternately provides line pressure to one side of the apparatus while exhausting the other, and momentarily supplies both sides with pressure between each changeover from pressure to exhaust. A manually operated release valve is connected to one side of the stock gripper and is adapted to exhaust pressure from the feeding gripper allowing it to open to facilitate loading and unloading of the stock feed apparatus. In this way, the line pressure remains connected to the mechanism while stock is inserted or removed therefrom. For purposes of adjusting the length of feed strokes an adjusting piece, with a bumper threaded thereon, is secured to the stationary body to provide for continuous adjustment of the length of the feed stroke.

BRIEF DESCRIPTION OF THE DRAWING The features and advantages of this novel reciprocating stock feed apparatus will become apparent from the following detailed description when read in conjunction with the accompanying drawing, in which: 7

FIG. I is a plan view of the reciprocating stock-feeding apparatus of the present invention;

FIG. 2 is an elevational sectional view of the stock-feeding apparatus taken along cutting plane 22 of FIG. I;

FIG. 3 is a sectional plan view taken generally along cutting plane 3-3 of FIG. 2;

FIG. 4 is a sectional view taken along cutting plane 4-4 of FIG. 1 showing the control valve in normal position;

FIG. 5 is a sectional view similar to FIG. 4 showing the control valve in a second position; and

FIG. 6 is a diagrammatic arrangement showing the fluid passageways and fluid motors and the pressures existing therein when the stock feeding apparatus is in its normal position.

DESCRIPTION OF THE PREFERRED EMBODIMENT The drawing shows one embodiment of this novel stock feeding apparatus in what is herein referred to as normal position," that is, the position of the feeding apparatus at the end of a feed stroke. FIG. 5 shows the control valve in a second operative position different from the normal position. Although the mechanism herein described is intended to be operated with compressed air, it may also be adapted for hydraulic fluid operation with the addition of a simple exhaust sump having a feedback connection to the fluid supply means. Thus, despite the use herein of the terms air" and air pressure" in reference to the prime mover, it should be understood that the principles of this invention are not strictly limited to air pressure operation.

The stock-feeding apparatus may be considered as being comprised of two structural groups; the main structural members and the operating and control members. For purposes of clarity, the details of these two structural groups are separately described followed by a description of the overall operation of the apparatus.

MAIN STRUCTURAL MEMBERS The main structural members generally include reciprocating feed head 11, stationary body 12, the main piston cylinder and rod assemblies (specifically enumerated below) and rear guide 21, as shown in FIGS. 1, 2 and 3. Referring specifically to FIG. 3,

parallel piston rods

13 and 14 pass through feed head 11, extend into

bores

15 and 16 in stationary body 12, and are anchored therein by means of setscrews l7 and 18 respectively. Rear guide 21 is secured to the rearward ends of

piston rods

13 and 14 by means of screws 22. Feed head 11 is slidably mounted on the piston rods by means of

bearings

23 and 24 circumscribing rod 13 and

bearings

25 and 26 circumscribing rod 14.

Piston rod 13 is formed with piston 27 disposed between

bearings

23 and 24 in feed head 11. A retaining ring 31 is secured to the piston rod near its forward end and forward of bearing 24. When the feeding apparatus is constructed, rod 13 is inserted into bore 15 in stationary body 12 until retaining ring 31 resets against shoulder 32. The rod is then secured in place by setscrew l7. Longitudinal bore 33 extends axially through rod 13 from its forward end to transverse bore 34 just forward of piston 27. Forward end of bore 15 is thus in direct communication with that portion of bore 35 in feed head 11 which is forward of piston 27. O-ring 36 in groove 37 near the forward end of rod 13 resiliently contacts the surface of bore 15 to form an airtight seal therewith. The seal between piston 27 and bore 35 in feed head 11 is provided by a glide ring 41 which encircles, and is resiliently forced outward by, O-ring 42. Bearing 23 seals the rearward end of bore 35 around shaft 13 in a manner similar to the seal of piston 27 inside of the bore, that is, by means of glide ring 43 and resilient O-ring 45 and O-ring 46.

The glide rings may be made of a suitable long-lasting selflubricating plastic such as nylon or polytetrafluoroethylene, sold under the duPont trademark Teflon. The O-rings are a conventional material such as neoprene. The frequent replacement of worn seals which has been a major source of reliability problems with existing stock feeders is substantially reduced by the seals disclosed herein. These glide ring-O-ring seals are preferably used in the present mechanism where a substantial relative sliding motion occurs between two mem bers and where an airtight seal must be maintained between them. The seals used in the invention herein described substantially increase the operating time between seal replacements and thereby increase the reliability of the apparatus by a significant factor.

Piston 53 on rod 14 is similarly sealed within bore 47 by means of O-ring 51 and its enclosing glide ring 52, while ring 54 and its enclosing glide ring 55 seal bearing 25 to rod 14 and enclose the rearward end of bore 47. O-ring 56 and its enclosing glide ring 57 seal bearing 26 around shaft 14 and enclose the forward end of the bore. Rod 14 is formed with longitudinal internal bore 61 extending from the forward end of the rod to transverse bore 62 positioned rearwardly of piston 53. It is thus readily apparent that the forward end of bore 16 communicates directly with that portion of bore 47 which is rearward of piston 53. O-ring 63 seals rod 14 to bore 16 immediately rearward of reduced diameter portion 64 of the rod. Retaining ring 65 is fixed to rod 14 and abuts shoulder 66 on stationary body 12 in a manner similar to retaining ring 31 on rod 13.

As shown in FIGS. 1 and 2, adjusting rod 71 is threadedly engaged with stationary body 12 and is prevented from unintentional rotational motion by means of roll pin 72 which extends through the forward end of adjusting rod 71 and upright portion 73 of stationary body 12. The central portion of adjusting rod 71 passes freely through bore 74 in upright portion 75 of feed head 11. Reduced diameter portion 79 of bumper element 77 fits partially within internally threaded feedlength-adjusting piece 76. This bumper is made of a suitable long lasting, resilient, shock-absorbing material such as nylatron. Adjusting piece 76 and bumper 77 are fixed on adjusting 71 at any desired point rearward of facing 92 on feed head 11 by means of jamnut 78. Feed-length-adjusting piece 76 has an externally knurled portion to facilitate manual longitudinal adjustments afterjamnut 78 has been loosened. Adjusting piece 76 is also provided with hexagonal portion 81 adapted to be engaged by a wrench to hold the adjusting piece in place while jamnut 78 is being tightened against it or when it is being disengaged therefrom.

Rear guide 21 is formed with channel 82 adapted to slidingly engage slotted guide member 83 having front stock guide 84 formed thereon. Guide member 83 is secured to rear guide 21 by means of screw 85 which is threadedly engaged with rear guide 21. By looseningscrew 85 guide member 83 may be slid in groove 82 so that front stock guide 84 makes light contact with the front edge of stock of various widths. The back edge of the stock, as defined by stock line SL in FIGS. 1 and 2, contacts wear

pins

86 and 87 on feed head 11 and stationary body 12 respectively. In this manner, the path which the stock must take as it passes through the stock-feeding apparatus is accurately defined.

Feed head 11 is provided with cutout area 91 at the rearward end of upright portion 75 to define vertical facing 92 which makes contact with bumper 77 at the end of each indexing stroke of the feed head. Stationary body 12 is shown with an identical cutout area and vertical face, primarily to enable each of the main structural portions 11 and 12 of the apparatus to be made from the same basic castings, if desired. By using the same castings, a substantial savings is realized in the preliminary formation of these body members.

The flow of air throughout the stock-feeding apparatus is controlled by a control valve which is located in bore 93 in stationary body 12. The valve is formed with a stem 94 extending above vertical section 73 of stationary body 12 and is fitted with a slidable cap 95. The line air pressure may be fed to either the front or back of stationary body 12 and is shown in FIG. 1 connected by suitable conventional fitting 96 to the back of the stationary body. Fitting 96 may be connected to tapped hole 97 at the back or tapped hole 98 at the front of stationary body 12 (shown in FIG. 3).

Operating and Control Members The operating and control members generally comprise the control valve, the gripping and clamping pistons, the braking piston and the release valve, shown in FIGS. 2, 3 and 4. Control valve 90 resides in bore 93 which passes entirely through stationary body 12 including upright portion 73 thereof Control valve bearing 101 is a sleeve having a closed lower end 102 and is equal in length to bore 93 in which it is mounted.

Annular grooves

103, 104 and 105 are provided at predetermined spaced intervals around the exterior of bearing 101, each of said grooves being in communication with the bearing interior by means of a plurality of

holes

106, 107 and 108 respectively, spaced around each groove. With this construction, bearing 101 may be inserted within bore 93 without regard for rotational alignment. Snap ring 11 1 fits within groove 112 near the top of bearing 101 to limit the upward travel of the control valve.

Control valve 90 is formed with piston 114 at its lower end, piston 1 15 spaced therefrom and enlarged portion 116 spaced a short distance farther beyond piston 115. Enlarged portion 116 abuts snap ring 111 when the valve is in its upper, or normal, position. Above enlarged portion 116 is stem 94 topped by another enlarged portion 117. Each piston is hermetically and slidably sealed within bearing 101 by means of glide rings and O-rings in a manner similar to that with which

main pistons

27 and 53 are sealed within their respective bores 35 and 47. Axial bore 127 and counterbore 128, having a transitional shoulder 131 therebetween, are formed in control valve 90. A compression spring 132 is located within axial counterbore 128, one end abutting shoulder 131 and the other end supported by lower end 102 of bearing 101. This spring biases control valve 90 upwardly, its upward movement being limited by snap ring 111 in contact with enlarged portion 116. Enlarged portion 116 is formed with diametrically opposed arcuate longitudinal grooves 133. These grooves provide communication to the atmosphere for ore 127 and counterbore 128, through transverse bore 135 and annular area 134 surrounding the valve between enlarged portion 116 and piston 115. It is immediately apparent from the above description that the lower portion of bearing 101 below piston 114 is always exhausted to atmosphere.

Control valve 90 is also provided with upper axial ore 136 in which is axially disposed compression spring 137. The upper end of spring 137 is seated in depression 141 in cap 95. The upward movement of cap 95 is limited by snap ring 142 which ears against the lower surface of enlarged area 117 of the valve stem. Spring 137 is normally stiffer than spring 132 so that when downward force is applied to the top of cap 95 valve 90 moves downward within bearing 101 before cap 95 moves with respect to the valve stem. The significance of this operation will be discussed below under Details of Operation.

With specific reference now to FIG. 2,

independent pistons

151 and 164 are shown mounted for reciprocating movement in feed head 11 and stationary body 12 respectively. These pistons operate the stock gripper an clamp in response to air pressure selectively supplied by the control valve. Piston 151 and its connected gripper rod 152 are sealed to the side of bore 153 and an airtight seal between bearing and bore is provided by O-ring 155. Accidental removal of the bearing is prevented by snap ring 156 residing in groove 157 in the feed head. O-ring 161 and 162 provide slidable airtight seals between piston 151 and ore 153 and rod 152 and bearing 154 respectively. Although the glide ring-O-ring combination could be used for sealing piston 151 and gripper rod 152, 0- rings have proved satisfactory for this purpose because of the very small distance which the piston moves, this distance being in the order of 0.050 inch or less, depending upon stock thickness. The resulting sliding friction is so small that wear is not a factor with these pistons. In order to improve the speed of response of piston a significant portion of the space between the piston and the bottom of ore 153 is occupied by piston extension 163. With the volume which must be occupied by the primemover thus decreased, the opening below piston 151 fills significantly faster than it otherwise would and the response time of the piston is commensurately decreased. A leaf spring 168 is secured to feed head 11 by means of screw 169 and engages notch 170 in the top surface of gripper rod 152. This leaf spring biases piston 151 downward just enough to overcome friction, while at the same time providing a ramp to facilitate the insertion of strip material into the mechanism between rear post 158 and gripper rod 152.

Piston 164 and clamping rod 165 are similarly sealed within bore 166 in stationary body 12. Bearing 167 is sealed against bore 166 by means of Oring 171 and is maintained in position by means of snap ring 172. Piston 164 is sealed against the side of bore 166 by means of O-ring 173 while clamping rod- 165 is sealed against the side of caring 167 by means of O-ring 174. Piston 164 is similarly constructed with extension 163 on piston 151.

Rear post 158 extends outwardly from upright portion 75 of feed head 11 toward the front of the mechanism and presents a linearly curved surface 1580 against which the stock is held by means of the flat upper surface of gripper rod 152. Rear post 158 is secured within bore 750 (see FIG. 1) in a suitable manner such as by means of setscrew 158b. Forward post 159 is secured within ore 73a in upright portion 73 of body 12 by means of setscrew 160. It, too, presents a lower linearly curved surface 159:: against which the stock is clamped by means of the upper flat surface of clamping rod 165. The portion of forward post 159 within bore 73a is configured differently than is rear post 158, for reasonswhich will be explained later.

Existing machines which use fiat surface contact for gripping the stock are subject to feed length irregularities due to variations in the thickness of most stock. With the stock feeder herein disclosed, however, the flat surface of each rod contacting the rounded side of each post results in line contact with the stock, thereby creating a roper grip unaffected by surface roughness or irregularities in the stock thickness.

Near the end of each feeding stroke, feed head 11 contacts piston rod 176 which is connected to braking piston 177 mounted within bore 181 in stationary body 12. Bearing 182 is sealed against the side of bore 181 by meansof O-ring 183 and is prevented from being accidentally removed from the bore by means of snap ring 184. The proper seal between piston 177 and bore 181 is provided by O-ring 185 and glide ring 1850 while the seal between bearing 182 and piston rod 176 is provided by O-ring 186. Piston rod 176 protrudes from stationary body 12 and its rearward end 187 makes contact with the forward facing of feed head 11 just prior to the end of each feeding stroke. Due to pressure which forces piston 177 rearwardly, the velocity of feed head 11 is sharply reduced just prior to the end of its forward travel. The air in the chamber forward of piston 177 is forced through a small orifice under the momentum of the feed head so that the air pressure existing in the apparatus absorbs the kinetic energy of the feed head and prevents it from stopping too abruptly.

With the feeding mechanism shown in its normal position in FIG. 2, the stock is held tigh'tly between gripper rod 152 and rear post 158. Loading and unloading of the mechanism is facilitated by means of release valve 191 connected to the chamber below piston 151 by means of passage 201. This valve is hand operated and is simply pressed upward whenever it is desired to release the stock from the rear gripper. In its normal condition, release valve 191 is biased downward by air pressure and returns to normal position when released by a combination of the force of gravity and the trapped compressed air in bore 192 above the valve. The release valve is sealed for sliding motion to the side of bore 192 by means of O-ring 194. Valve stem 195 has a flat cutout area 196 through which the pressure at the base of piston 151 is released when the valve is moved upward. The valve stem has a second flat area 197 above O-ring 194 on the forward side of the valve which is normally in communication with the upper end of ore 192 and with the lower end of piston bore 153 by means of the aforesaid passageway 201 and transverse hole 198 through valve stem 195. Lip 202 at the upper end of the valve makes contact with setscrew 193 and prevents release valve 191 from falling out of bore 192.

Details of Operation The operation of the structure whose elements have been described above will now be set forth in detail. The prime mover which is supplied under pressure to the stock-feeding apparatus is directed through various portions of the apparatus by means of passageways under the control of fourway valve 90. It will be assumed for purposes of this description that the prime mover is air although it could be any other suitable fluid. The air supply may be connected at the back of stationary body 412 by means of fitting 96 connected to tapped hole 97 to supply air to spool valve 90 through passageway 205. An alternative connection would be to the front of the stationary body by means of tapped hole 98 and the air would then be supplied to the spool valve by means of passageway 206.

It is readily apparent from FIGS. 4 and 5 that full line pres sure always exists in the cylindrical area around valve 90 rounding the central portion of front post 159 within upright portion 73 of stationary body 12. The back end of front post 159 is stationarily secured within upright portion 73 and is sealed against the side of bore 73a by means of O-rings 212 and 213. The air pressure in opening 207 is communicated to bore forward of main piston rod 13 through vertical passageway 214 (see FIG. 2) and thence to the upper side of clamping piston 164 by means of lateral passageway 215 (see FIG. 3). This pressure is further communicated to bore 181 forward of piston 177 by means of orifice 216. From the forward end of bore 15 in stationary body 12 the line pressure passes through bore 33 in rod 13 to cylindrical area 217, between piston 27 and bearing 24, by means of transverse bore 34. Passageway 221 in feed head 11 provides communication of this pressure from area 217 to a similar cylindrical area 222 surrounding piston rod 14 forward of piston 53. This pressure is also communicated to the bottom of gripping piston 151 by means of passageway 201 and the hole 198 through release valve stem 195.

The crosshatched passageways shown diagrammatically in FIG. 6 indicate the portions of the mechanism which are normally under full line pressure. It should be noted that control valve 90 and its cap 95 are maintained in their normal positions by means of

springs

132 and 137 respectively and that the line pressure between

pistons

114 and 115 of the valve has no effect upon its position within bearing 101. With further reference to FIG. 6, it is evident that when the stock-feeding apparatus is in its normal condition, stock-clamping piston 164 is biased downward to an open position, braking piston 177 is biased rearward toward sliding member 11 in full brak ing position, release valve 191 is biased downward and sliding member 11 is biased to its forward or feeding position.

The other side of the pistons, passageways, and valves, which were not included in the foregoing discussion of the portions of the mechanism under pressure, are exhausted to the atmosphere. The area 223 within bearing 101 between valve piston 114 and closed end 102 of the bearing is exhausted to the atmosphere through counter bore 128 and bore 127 which are axially disposed within valve 90, through transverse bore 135 to annular opening 134 and thence to the atmosphere through grooves 133 on either side of enlarged portion 116 (FIG. 4). That portion of bore 166 in stationary body 12 below clamping piston 164 communicates with the atmosphere through passageway 224 to area 223 (see FIGS. 2, 3 and 6). The portion of bore 16 forward of piston rod 14 is exhausted through passageway 225 to the lower portion of bore 166, while bore 181 rearward of braking piston 177 is exhausted by means of passageway 226 which opens into bore 16 adjacent the annular area 227 surrounding reduced diameter portion 64 of rod 14. The portion of feed head main bores 35 and 47 rearward of

pistons

27 and 53 respectively are interconnected by means of passageway 231 and are exhausted to atmosphere through transverse bore 62 and longitudinal bore 61 in rod 14, the latter bore opening into the forward end of bore 16 in stationary body 12. The upper side of gripping piston 151 is exhausted to atmosphere by connection with passageway 231 through passageway 232. It is thus apparent that there is normally no pressure acting upon the bottom of piston 164, the top of piston 151, the rearward side of braking piston 177, and the rearward side of

pistons

27 and 53 which would in any way tend to counteract the line pressure existing on the opposite sides of these pistons.

When the parent work machine commences its downward stroke it makes contact with cap 95 of valve 90 by suitable means such as an operating rod (not shown) which forces the cap downward. As shown in FIG. 4, spring 132, which is weaker than spring 137, is compressed by the downward motion of valve 90 before spring 137 is compressed and before cap 95 slides downward along stem 94, As valve 90 progresses downward, piston 114 first closes off the exhaust side of the apparatus by closing access holes 106 so that passageway 224 no longer communicates with exhaust area 223 below piston 114. Further downward movement of the valve connects passageway 224, through annular groove 103 and holes 106 in bearing 101, to the line pressure existing in the cylindrical portion around the valve between

pistons

114 and 115. At this instant in time, before the side of the mechanism normally under pressure is exhausted, both sides of the apparatus, that is, the entire system, is exposed to full line pressure. Clamping piston 164 momentarily becomes a differential piston and is forced upward because the area of the bottom of the piston is greater than the area of the top, both top & bottom being exposed to the same pressure. The pressure on the upper side of gripper piston 151, which is also a differential piston for a moment, increases but the piston remains in an upward or closed position because of its greater bottom area. Thus, for a fraction of the downward travel of control valve before feed head 11 commences its indexing stroke, both gripping and clamping members are forced into closed positions and prevent any spurious motion of the stock in the machine. At this point also, feed head 1 1 has not yet commenced its indexing motion. The pressure on the rearward side of the main pistons builds up relatively slowly due to the special configuration of

bearings

23 and 25 in feed head 11. These bearings are constructed with

shoulders

233 and 234 respectively which partially block the ends of passageway 231 and transverse bore 62, as shown in FIG. 3. The resulting metering effect increases the time required for the pressure on the rearward sides of

pistons

27 and 53 to build up to line pressure, allowing both clamping piston 164 and gripping piston 151 to be urged upward to grip the stock before any movement of feed head 11 occurs. It should be remembered that at this point in the operating cycle there is some rearward force, although small, on the feed head exerted by braking piston 177 because it, too, is a differential piston for the same momentary period in the cycle. It should also be noted that

pistons

27 and 53 are not differential pistons so that, ignoring other forces which might be present, even if the pressure became equal on both sides of these pistons the feed head would remain in whatever position it was in at the time the pressure was equalized.

The pressure on the rearward side of braking piston 177 also builds up to line pressure but the piston is still urged in a rearward direction because of the pressure on the forward side of the piston which more than balances the pressure on the opposite side. As the pressure on the rearward side of braking piston 177 builds up, the actual force which piston rod 176 exerts in the rearward direction upon feed head 11 is decreased and is more than counteracted by the pressure which still urges the feed head forward.

.As control valve 90 continues downward to the position shown in FIG. 5, piston 115 passes holes 108 and passageway 211 from bore 73a becomes exhausted to atmosphere through annular groove 105, holes 108, annular area 134 and exhaust grooves 133. When the control valve reaches this position, the entire side of the feed mechanism which was originally under line pressure when the mechanism was in normal condition is fully exhausted to atmosphere while the other side of the mechanism which was originally at atmospheric pressure is now maintained at line pressure. This piston 164 ceases to become a differential piston in actual operation and is urged upward with even greater force because there is no partial balancing force on the upper side thereof. Similarly, piston 151 is urged downward to disengage the stock because of the rapid decrease in pressure on the lower side of that piston together with the downward bias of leaf spring 168. Also the forward side of the raking piston 177 is exhausted so that piston rod 176 is urged to the left to prevent any spurious force against feed head 11 which might otherwise cause a false start in the indexing direction. As the pressure on the forward side of

pistons

27 and 53 is reduced, the line pressure on the rearward side of these pistons causes feed head 11 to move in the indexing direction a distance which is controlled by the position of adjusting piece 76 and bumper 77.

As the parent machine completes its downward movement a distance longer than the length of travel of valve 90, cap continues downward but in no way further affects the operation or control of the stock feeding mechanism. FIG. shows the control valve at the extent of its downward travel with cap 95 having moved downward somewhat with respect to stem 94. This dual-spring arrangement of control valve 90 allows the indexing and feeding portions of the stock-feeding mechanism to take place somewhat independently of the length of travel of the operating head of the parent machine. Thus the downward stroke of the parent machine may be substantially greater than the distance allowed for the travel of control valve 90 and this additional distance is absorbed by the telescoping action of cap 95. This arrangement also allows the indexing stroke of feed head 11 to be completed before the stock is actually acted upon by the parent machine so as to ensure that the stock is absolutely stationary when the parent machine performs its function. It should be noted that with a given control valve travel distance, any length of workmachine travel may be accounted for by constructing a proper length valve stem 94 and sliding cap 95.

As the parent machine commences its return to normal position, cap 95 first moves upward under the urging of its spring 137 until it reaches its upper limit so that the operating portion of the parent machine is removed from the work area before control valve 90 is permitted to move upward under the urging of spring 132. Valve 90 then commences to rise and piston 115 immediately closes off the atmosphere exhaust of passageway 211 as it passes holes 108. As the control valve continues to rise, piston 115 exposes holes 109 and consequently the side of the mechanism which was exhausted on the downward stroke is subjected to the line pressure which always exists around the valve between

pistons

114 and 115. Once again all the operating portions of the stock-feeding mechanism are momentarily under line pressure and both gripping piston 151 clamping piston 164 are urged upward to grip the stock, both once again momentarily acting as differential pistons. Braking piston 177 is urged rearwardly in preparation for absorbing the shock of feed head 11 at the end of the next feed stroke. The pressure on both sides of

pistons

27 and 53 tends to become equalized but the feed head is not urged forward because there is no resultant forward force. As control valve 90 continues upward, passageway 224 becomes exhausted to atmosphere and the mechanism returns to the condition shown in FIGS. 4 and 6 so that piston 164 is urged downward, piston 151 is urged upward and the feed head is urged downward, piston 151 is urged upward and the feed head is urged forward to perform a feeding stroke.

As feed head 11 moves forward and approaches the end of the feed stroke, it contacts protruding end 187 of braking piston rod 176. As indicated in FIGS. 2 and 3, orifice 216 is quite small compared with bore 181 so that the air in bore 181 forward of piston 177 is highly compressed while relatively slowly passing through the orifice. Thus the air in bore 181 forward of braking piston 177 is forced through orifice 216 by the force of feed head 11 on the braking piston but the size of the orifice is such that the braking piston absorbs most of the momentum of feed head 11 before it comes to rest against stationary body 12. It has been found that a ratio in the range of several hundred to one between the area of bore 181 and the area of orifice 216 will provide the desired braking action of piston 177. Of course, the ratio necessary will depend upon the air pressure involved and the mass and speed of the feed head.

Bumpers

235 and 236 are provided on the forward face of feed head 11 to quietly finally halt the feed head and absorb the remainder of its kinetic energy. These bumpers are a suitable long lasting energy-absorbing material, such as nylatron, similar to bumper 77.

Release valve 191, shown in FIG. 2, is provided to facilitate loading and unloading the stock-feeding mechanism. When the parent machine is stopped and the stock-feeding mechanism is in normal position as indicated in the drawing, the stock is not clamped between clamping rod 165 and forward post 159 but is gripped tightly between gripper rod 152 and rear post 158. When the mechanism is in this condition, pressure exists in the release valve bore 192 above flange 241,

thereby forcing valve 191 downward. The actual downward force involved is not great due to the small cross section of the valve and may be easily overcome by pressing upward on button 242 at the lower end of release valve 191. As valve 191 travels upward, cutout area 196 becomes aligned with the rearward part of passageway 201 which connects with the lower portion of bore 153, thereby bleeding off the air on the lower side of piston 151. This allows the piston to drop under the double influence of gravity and leaf spring 168 so that the stock if free to be removed or new stock may be inserted into the machine. Stem 105 of the release valve fits tightly in bore 192, and effectively seals off the forward portion passageway 201 which connects with passageway 221 so that the remainder of the feeding apparatus remains under pressure as in its normal condition while piston 151 is being exhausted.

From the foregoing description of the operation of this stock-feeding mechanism it is apparent that a definite timed relationship exists and is maintained between the operations of all of the fluid-pressure-controlled parts of the machine. This timed relationship is maintained by the single four-way control valve 90, which operates through the above described passageways and orifices. This control valve ensures that the stock is tightly clamped to the stationary body before the feed head starts an indexing stoke and that the stock is gripped securely on the feed head before the commencement of a feed stroke. The valve provides full pressure on the braking piston in time to absorb the momentum of the feed head at the end of the feed stroke, but urges the braking piston in the reverse direction just prior to an indexing stroke in order to prevent spurious motion of the feed head. This timing is, of course, es-

' sential to the proper and efficient operation of the stock feed apparatus described herein.

As previously mentioned,

extensions

163 and 175 of

pistons

151 and 164 respectively occupy a significant amount of the space in

bores

153 and 166 beneath their respective pistons. Since this volume is relatively small, the pistons react very quickly because the pressure beneath them builds up rapidly, thus enhancing the speed at which the stock-feeding system may operate. The bottom of each bore 153 and 166 is formed with

bosses

242 and 243 respectively to maintain the piston slightly above the bottom of their respective bores when they are in the lower position. This provides for shorter piston travel and more positive piston action by allowing the air to readily fill the space beneath the piston. By maintaining a separation between the piston and the bottom of the bore any possibility of a vacuum being formed between two flat surfaces is eliminated. Threaded

holes

224 and 245 are sealed by means of

plugs

246 and 247 respectively. If at any time it is desired to remove the bearings and pistons from

bores

153 and 166, plugs 246 and 247 may be removed and the bearings and pistons simply pushed outwards by inserting an elongated tool through these holes.

The stock-feeding apparatus herein described in very efficient and fast acting while being economical to operate and maintain. It can operate effectively on air pressure in the range of 50-120 p.s.i., with normal pressure being approximately p.s.i. Of course, it can be adapted for fluids and for much higher pressures if desired. In order to facilitate mounting the stock-feeding apparatus on the work machine, holes 251 and 252 are provided in stationary body 12 into which suitable mounting means such as bolts may be inserted for attachment to the parent machine. The materials used in the stock-feeding mechanism are for the most part conventional for such a device. The piston rods and valves are generally made of tool steel and the bearings are either bronze or steel. The O-rings are conventional neoprene and the glide rings are nylon, Teflon or other suitable self-lubricating, long lasting plastic. However, feed head 11 and stationary body 12 are made of cast aluminum. With these main body portions being made of aluminum, the entire mechanism is lighter and easier to handle than similar stock-feeding mechanisms which are made entirely of steel or other relatively heavy alloys. Furthermore, since the feed head is relatively light, it is able to react llll more quickly and positively to the various changes in pressures in the operating portions of the mechanism. Furthermore, energy which braking piston 177 must absorb is substantially reduced through the use of aluminum for the feed head. This combination of a light aluminum feed head and the braking piston practically eliminates any possibility of continued motion of the stock at the end of each feeding stroke due to its inertia.

It is to be understood that the above-described preferred embodiment is merely illustrative of the principles of this invention. For instance, although the drawing shows a dual main piston and cylinder arrangement, it is possible that a single piston and cylinder construction could be used. In such cases a guide bar would be necessary to maintain the attitude of the feed head and both

air passages

33 and 61 would necessarily be located within one rod. However, the principles of the invention would still apply. Furthermore, the

bumpers

235 and 236 could be mounted on the stationary body as well as on the feed head. Numerous other embodiments may be devised in accordance with these principles by those skilled this art without departing from the spirit and scope of the invention as defined by the appended claims.

What I claim is:

l. A stock-feeding apparatus operable through alternate feed and indexing strokes for incrementally feeding stock to a work-performing machine in synchronism with the operating cycle thereof, said stock-feeding apparatus being powered by a fluid prime mover and comprising:

a stationary body;

a feed head;

means for connecting said feed head to said stationary body for reciprocal rectilinear motion with respect thereto; fluid-pressure operated means for controlling the rectilinear motion of said feed head; fluid-pressure-operated energy-absorbing means mounted between said stationary body and said feed head, said energy-absorbing means being operable between energyabsorbing and retracted positions; and means including a control valve for controlling the application of fluid pressure to said means for controlling the rectilinear motion of said feed head and to said energyabsorbing means;

said control valve providing fluid pressure to said energyabsorbing means in timed relationship with the fluid pressure applied to said means for controlling the rectilinear motion of said feed head so that said energy-absorbing means absorbs the kinetic energy of said feed head through an incremental distance of the travel of said feed head at the end of said feed stroke.

2. The stock-feeding apparatus recited in claim 1, wherein:

said control valve provides fluid pressure to urge said energy-absorbing means to said energy-absorbing position while providing fluid pressure to said means for controlling the rectilinear motion of said feed head to urge said feed head in a feeding direction; and

said control valve provides fluid pressure to urge said energy-absorbing means to said retracted position while providing fluid pressure to said means for controlling the rectilinear motion of said feed head to urge said feed head in an indexing direction.

3. The stock-feeding apparatus recited in claim 2, wherein:

said stationary body is formed with a cylinder therein;

said energy-absorbing means includes a double-acting piston mounted in said cylinder and a rod attached to said piston adapted to protrude rearwardly from said cylinder toward said feed head.

4. The stock-feeding apparatus recited in claim 3, wherein:

said stationary body if formed with an orifice communicating the pressure from said control valve with the forward end of said cylinder;

said energy-absorbing means is urged to said energy-absorbing position when fluid pressure is supplied to said cylinder forward of said piston;

the kinetic energy of said feed head is absorbed by compression of the fluid in said cylinder and the release of said fluid through said orifice, the cross-sectional area of said orifice being so related to the cross-sectional area of said cylinder that a substantial portion of the kinetic energy of said feed head is absorbed during the time required for the excess pressure in said cylinder to be released through said orifice.

5. A stock-feed apparatus operable through alternate feed and indexing strokes for incrementally feeding stock to a work-performing machine in synchronism with the operating cycle thereof, said stock-feeding apparatus being powered by a fluid prime mover and comprising:

a stationary body;

a feed head;

means for connecting said feed head to said stationary body for reciprocal rectilinear motion with respect thereto; fluid-pressure-operated means for controlling rectilinear motion of said feed head;

the

fluid-pressure-operated stock-gripping means mounted on said feedhead and movable between gripping and releasing positions, said stock-gripping means being normally in said gripping position;

means including a control valve for controlling the application of fluid pressure to said stock-gripping means in timed relationship with the fluid pressure applied to said means for controlling therectilinear motion of said feed head; and

a release valve for selectively moving said stock-gripping means to said releasing position, said release valve being movable between open and closed positions and being normally urged to said closed position by said fluid pressure, said release valve being formed with a hole therethrough the transmit fluid pressure to said stockgripping means from said control valve when in said normally closed position;

said release valve being shaped and configured to interrupt the supply of fluid pressure from said control valve to said stock-gripping means and to exhaust fluid pressure from said stock-gripping means when in said open position.

6. A stock-feeding apparatus operable through alternate feed an indexing strokes for incrementally feeding stock to a work-performing machine in synchronism with the operating cycle thereof, said stock-feeding apparatus being powered by a fluid prime mover and comprising:

a stationary body;

a feed head;

means for connecting said feed head to said stationary body for reciprocal rectilinear motion with respect thereto; fluid pressure operated means for controlling the rectilinear motion of said feed head;

fluid-pressure-operated stock-gripping means mounted on said feed head and movable between gripping and releasing positions;

fluid-pressure-operated stock-clamping means mounted on said stationary body and movable between clamping and releasing positions; and

means including passageways defining first and second operative sides of said apparatus and a control valve for controlling the application of fluid pressure through said passageways to said means for controlling the rectilinear motion of said feed head, to said stock-gripping means and to said stock-clamping means;

said control valve providing fluid pressure alternately to said first and second operative sides and cooperatively with said passageways providing fluid pressure in timed relationship to said fluid-pressure-operated stockgripping, clamping and rectilinear-motion-controlling means;

said control valve providing fluid pressure to said first operative side when in a first position and providing fluid pressure to said second operative side when in a second position;

said control valve further simultaneously applying fluid pressure to both said first and second operative sides when in a momentary position, said control valve passing through said momentary position each time it passes between said first and second positions.

7. The stock-feeding apparatus recited in claim 6, wherein:

said stationary body is formed with a control valve bore therein; and

said control valve is a four-way valve mounted for longitudinal movement in said bore and connected with said passageways.

8. The stock-feeding apparatus recited in claim 7 wherein:

said control valve includes a stem mounted one end thereof and a cap telescopically mounted on said stem, said stock-feeding apparatus further comprising:

first means for continuously biasing said control valve to said first position; and

' second means for biasing said cap away from said control valve, said second biasing means being stronger than said first biasing means;

said cap being contacted by said work-performing machine during its work-performing cycle so as to move said control valve from said first position through said momentary position to said second position, said work-performing machine then continuing movement in the same direction to perform work on said stock, thereby telescoping said cap on said stern toward said control valve, said work machine then retracting from the vicinity of said stock before said control valve returns to said first position to initiate another cycle of said stock-feeding apparatus.

9. A stock-feeding apparatus operable through alternate feed and indexing strokes for incrementally feeding stock to a work-performing machine in synchronism with the operating cycle thereof, said stock-feeding apparatus being powered by a fluid prime mover and comprising:

a stationary body;

a feed head;

means for connecting said feed head to said stationary body for reciprocal rectilinear motion with respect thereto; fluid-pressure-operated means for controlling rectilinear motion of said feed head; fluid-pressure-operated stock-gripping means mounted on said feed head and movable between gripping and releasing positions; fluid-pressure-operated stock-clamping means mounted on said stationary body and movable between clamping and releasing positions; and

means including passageways defining first and second operative sides of said apparatus and a control valve for controlling the application of fluid pressure through said passageways to said means for controlling the rectilinear motion of said feed heads to said stock-gripping means and to said stock-clamping means;

said stationary body being formed with a control valve bore therein, said control valve being a four-way valve mounted for longitudinal movement in said bore and connected with said passageways;

said control valve being formed with a first port connected the to said first operative side of said apparatus, a second port connected to said second operative side, a fluid pressure port and an exhaust port;

said control valve having normal and alternate main posi tions and a momentary position, said control valve passing through said momentary position when changing from one main position to the other;

said control valve normally connecting said fluid pressure port to said first port and said exhaust ort to said second port, and alternately connecting said urd pressure port to said second port and said exhaust port to said first port; said control valve connecting said fluid pressure port to both said first and second ports when in said momentary position. 10. The stock-feeding apparatus recited in claim 9 wherein: said means for controlling the rectilinear motion of said feed head includes a double-acting piston assembly having its forward side connected to said first operative side of said apparatus and its rearward side connected to said second operative side .of said apparatus; said stock-gripping means includes a double-acting differential piston assembly having its lower side connected to said first operative side of said apparatus and its upper side connected to said second operative side of said apparatus; said stock-clamping means includes a double-acting differential piston assembly having its upper side connected to said first operative side of said apparatus and its lower side connected to said second operative side of said apparatus; whereby said feed head is normally urged in a feeding direction, said gripping means is normally urged to a gripping position and said clamping means is normally urged to releasing position; whereby said feed head is alternately urged in an indexing direction, said gripping means is alternately urged to a releasing position and said clamping means is alternately urged to a clamping position; and whereby said feed head remains stationary, said clamping means is urged to a clamping position and said gripping means is urged to a gripping position when said control valve is in said momentary position. 11. The stock-feeding apparatus recited in claim 10, and further comprising:

fluid-pressure-operated energy-absorbing means mounted between said stationary body and said feed head, said energy-absorbing means being operable between energyabsorbing and retracted positions. 12. The stock-feeding apparatus recited in claim 11, wherein:

said energy-absorbing means includes a double-acting differential piston assembly having its forward side connected to said first operative side of said apparatus and its rearward side connected to said second operative side of said apparatus; whereby said energy-operative means is normally urged to said energy-absorbing position, alternatively urged to said retracted position and urged to said energy-absorbing position when said control valve is in said momentary position. 13. The stock-feeding apparatus recited in claim 9, and further comprising:

means for continuously biasing said control valve toward said normal position.

UNITED STATES PATENT OFFICE CERTIFICATE OF CORRECTION Patent No. 3 ,580/4-49 Dated May 25 1971 Inventor(g) Michael J. Chaban, Jr.

It is certified that error appears in the above-identified patent and that said Letters Patent are hereby corrected as shown below:

Column 3, line 25, "resets" should read --rests-;

line 37, change "45" to --44.--;and insert thereafter --Bearing 24 closes the forward end of bore 35 and is sealed about shaft 13 by means of glide ring 45--.

Column 4, line 6, after "justing" insert --rod--;

line 53, insert a period after "thereof".

Column 5, line 9, ore should read --bore--;

" should read --bore--;

line 35, "ore" should read --bore--;

- Page 1 of 3 Pages FORM PO-lOSO (10-69) USCOMM-DC 60375-P59 fl UYS GOVERNMENT PRINTING OFFICE I969 O366-33l Patent No.

Inventor(s) Column Column Column Column UNITED STATES PATENT OFFICE Dated May 25 1971 Michael J. Chaban, Jr.

line 44, "ore" should read --bore--;

line 61, "earing" should read --bearing--;

line 62, after "with" insert --extension 175 which operates in the same manner as--;

line 70, "ore" should read --bore--.

line 8, "roper" should read --proper--;

line 45, "ore" should read --bore--;

line 59, "412" should read --l2--.

line 29, after "position," insert -stock gripping piston 151 is biased upward to a closed position,--.

line 63, "raking" should read -braking--.

line 27, "109" should read --lO8-;

line 33, after "151" insert --and--;

line 45, after "urged" delete "downward feed";

- Page 2 of 3 Pages F ORM PO-105OHO-69] USCOMM-DC 6037G-PG9 Q U 5 GOVERNMENT PRINTING OFFICE: Ill! O-35$-33 Patent No.

UNITED STATES PATENT OFFICE CERTIFICATE OF CORRECTION Dated May 25, 1971 Inventor(s) Michael J. Chaban, Jr.

Column Column Column Column It is certified that error appears in the above-identified patent and that said Letters Patent are hereby corrected as shown below:

line 46, delete "head is urged".

line

Signed and "stoke" should read --stroke--;

"224" should read -244--;

"heads" should read --head,--.

after "to" insert --a--.

- Page 3 of 3 Pages sealed this 23th day of March 1 972.

(SEAL) Attest:

EDWARD M.FLETCHER, JR. Attesting Officer FORM PO-105O (IO-69) ROBERT GOT'ISCHALK Commissioner of Patents USCOMM'DC GO376-P69 US GOVERNMENT PRINTING OFFICE: l9! OSEO-3SI

Claims

1. A stock-feeding apparatus operable through alternate feed and indexing strokes for incrementally feeding stock to a workperforming machine in synchronism with the operating cycle thereof, said stock-feeding apparatus being powered by a fluid prime mover and comprising: a stationary body; a feed head; means for connecting said feed head to said stationary body for reciprocal rectilinear motion with respect thereto; fluid-pressure operated means for controlling the rectilinear motion of said feed head; fluid-pressure-operated energy-absorbing means mounted between said stationary body and said feed head, said energy-absorbing means being operable between energy-absorbing and retracted positions; and means including a control valve for controlling the application of fluid pressure to said means for controlling the rectilinear motion of said feed head and to said energy-absorbing means; said control valve providing fluid pressure to said energyabsorbing means in timed relationship with the fluid pressure applied to said means for controlling the rectilinear motion of said feed head so that said energy-absorbing means absorbs the kinetic energy of said feed head through an incremental distance of the travel of said feed head at the end of said feed stroke.

2. The stock-feeding apparatus recited in claim 1, wherein: said control valve provides fluid pressure to urge said energy-absorbing means to said energy-absorbing position while providing fluid pressure to said means for controlling the rectilinear motion of said feed head to urge said feed head in a feeding direction; and said control valve provides fluid pressure to urge said energy-absorbing means to said retracted position while providing fluid pressure to said means for controlling the rectilinear motion of said feed head to urge said feed head in an indexing direction.

3. The stock-feeding apparatus recited in claim 2, wherein: said stationary body is formed with a cylinder therein; said energy-absorbing means includes a double-acting piston mounted in said cylinder and a rod attached to said piston adapted to protrude rearwardly from said cylinder toward said feed head.

4. The stock-feeding apparatus recited in claim 3, wherein: said stationary body if formed with an orifice communicating the pressure from said control valve with the forward end of said cylinder; said energy-absorbing means is urged to said energy-absorbing position when fluid pressure is supplied to said cylinder forward of said piston; the kinetic energy of said feed head is absorbed by compression of the fluid in said cylinder and the release of said fluid through said orifice, the cross-sectional area of said orifice being so related to the cross-sectional area of said cylinder that a substantial portion of the kinetic energy of said feed head is absorbed during the time required for the excess pressure in said cylinder to be released through said orifice.

5. A stock-feed apparatus operable through alternate feed and indexing strokes for incrementally feeding stock to a work-performing machine in synchronism with the operating cycle thereof, said stock-feeding apparatus being powered by a fluid prime mover and comprising: a stationary body; a feed head; means for connecting said feed head to said stationary body for reciprocal rectilinear motion with respect thereto; fluid-pressure-operated means for controlling the rectilinear motion of said feed head; fluid-pressure-operated stock-gripping means mounted on said feed head and movable between gripping and releasing positions, said stocK-gripping means being normally in said gripping position; means including a control valve for controlling the application of fluid pressure to said stock-gripping means in timed relationship with the fluid pressure applied to said means for controlling the rectilinear motion of said feed head; and a release valve for selectively moving said stock-gripping means to said releasing position, said release valve being movable between open and closed positions and being normally urged to said closed position by said fluid pressure, said release valve being formed with a hole therethrough the transmit fluid pressure to said stock-gripping means from said control valve when in said normally closed position; said release valve being shaped and configured to interrupt the supply of fluid pressure from said control valve to said stock-gripping means and to exhaust fluid pressure from said stock-gripping means when in said open position.

6. A stock-feeding apparatus operable through alternate feed an indexing strokes for incrementally feeding stock to a work-performing machine in synchronism with the operating cycle thereof, said stock-feeding apparatus being powered by a fluid prime mover and comprising: a stationary body; a feed head; means for connecting said feed head to said stationary body for reciprocal rectilinear motion with respect thereto; fluid pressure operated means for controlling the rectilinear motion of said feed head; fluid-pressure-operated stock-gripping means mounted on said feed head and movable between gripping and releasing positions; fluid-pressure-operated stock-clamping means mounted on said stationary body and movable between clamping and releasing positions; and means including passageways defining first and second operative sides of said apparatus and a control valve for controlling the application of fluid pressure through said passageways to said means for controlling the rectilinear motion of said feed head, to said stock-gripping means and to said stock-clamping means; said control valve providing fluid pressure alternately to said first and second operative sides and cooperatively with said passageways providing fluid pressure in timed relationship to said fluid-pressure-operated stock-gripping, clamping and rectilinear-motion-controlling means; said control valve providing fluid pressure to said first operative side when in a first position and providing fluid pressure to said second operative side when in a second position; said control valve further simultaneously applying fluid pressure to both said first and second operative sides when in a momentary position, said control valve passing through said momentary position each time it passes between said first and second positions.

7. The stock-feeding apparatus recited in claim 6, wherein: said stationary body is formed with a control valve bore therein; and said control valve is a four-way valve mounted for longitudinal movement in said bore and connected with said passageways. 8. The stock-feeding apparatus recited in claim 7 wherein: said control valve includes a stem mounted one end thereof and a cap telescopically mounted on said stem, said stock-feeding apparatus further comprising: first means for continuously biasing said control valve to said first position; and second means for biasing said cap away from said control valve, said second biasing means being stronger than said first biasing means; said cap being contacted by said work-performing machine during its work-performing cycle so as to move said control valve from said first position through said momentary position to said second position, said work-performing machine then continuing movement in the same direction to perform work on said stock, thereby telescoping said cap on said stem toward said control valve, said work machine then retracting from the vicinity of said stock before said control valve returns to said firSt position to initiate another cycle of said stock-feeding apparatus.

9. A stock-feeding apparatus operable through alternate feed and indexing strokes for incrementally feeding stock to a work-performing machine in synchronism with the operating cycle thereof, said stock-feeding apparatus being powered by a fluid prime mover and comprising: a stationary body; a feed head; means for connecting said feed head to said stationary body for reciprocal rectilinear motion with respect thereto; fluid-pressure-operated means for controlling the rectilinear motion of said feed head; fluid-pressure-operated stock-gripping means mounted on said feed head and movable between gripping and releasing positions; fluid-pressure-operated stock-clamping means mounted on said stationary body and movable between clamping and releasing positions; and means including passageways defining first and second operative sides of said apparatus and a control valve for controlling the application of fluid pressure through said passageways to said means for controlling the rectilinear motion of said feed heads to said stock-gripping means and to said stock-clamping means; said control valve providing fluid pressure alternately to said first and second operative sides and cooperatively with said passageways providing fluid pressure in timed relationship to said fluid-pressure-operated stock-gripping, clamping and rectilinear-motion-controlling means; said stationary body being formed with a control valve bore therein, said control valve being a four-way valve mounted for longitudinal movement in said bore and connected with said passageways; said control valve being formed with a first port connected to said first operative side of said apparatus, a second port connected to said second operative side, a fluid pressure port and an exhaust port; said control valve having normal and alternate main positions and a momentary position, said control valve passing through said momentary position when changing from one main position to the other; said control valve normally connecting said fluid pressure port to said first port and said exhaust port to said second port, and alternately connecting said fluid pressure port to said second port and said exhaust port to said first port; said control valve connecting said fluid pressure port to both said first and second ports when in said momentary position.

10. The stock-feeding apparatus recited in claim 9 wherein: said means for controlling the rectilinear motion of said feed head includes a double-acting piston assembly having its forward side connected to said first operative side of said apparatus and its rearward side connected to said second operative side of said apparatus; said stock-gripping means includes a double-acting differential piston assembly having its lower side connected to said first operative side of said apparatus and its upper side connected to said second operative side of said apparatus; said stock-clamping means includes a double-acting differential piston assembly having its upper side connected to said first operative side of said apparatus and its lower side connected to said second operative side of said apparatus; whereby said feed head is normally urged in a feeding direction, said gripping means is normally urged to a gripping position and said clamping means is normally urged to releasing position; whereby said feed head is alternately urged in an indexing direction, said gripping means is alternately urged to a releasing position and said clamping means is alternately urged to a clamping position; and whereby said feed head remains stationary, said clamping means is urged to a clamping position and said gripping means is urged to a gripping position when said control valve is in said momentary position.

11. The stock-feeding apparatus recited in claim 10, and further comprising: fluid-pressure-operated energy-absorbing Means mounted between said stationary body and said feed head, said energy-absorbing means being operable between energy-absorbing and retracted positions. 12. The stock-feeding apparatus recited in claim 11, wherein: said energy-absorbing means includes a double-acting differential piston assembly having its forward side connected to said first operative side of said apparatus and its rearward side connected to said second operative side of said apparatus; whereby said energy-operative means is normally urged to said energy-absorbing position, alternatively urged to said retracted position and urged to said energy-absorbing position when said control valve is in said momentary position.

13. The stock-feeding apparatus recited in claim 9, and further comprising: means for continuously biasing said control valve toward said normal position.