US3326438A - Strip feed apparatus - Google Patents

Description

June 20, 1967 H. E. DICKERMAN STRIP FEED APPARATUS 7 Sheets-Sheet 5;

Filed Oct. 20, 1964 Ne Ev mm 8 Dow. m E V W HUBERT E. DICKERMAN ATTORNEY.

June 20, 1967 H. E. DICKERMAN STRIP FEED APPARATUS '7 Sheets-Sheet .3-

Filed Oct 20 1964 INVENTOR. HUBERT E. DICKERMAN ATTORNEY.

June 20, 1967 H. E. DICKERMAN STRIP FEED APPARATUS 7 Sheets-Sheet 4 Filed Oct 20, 1964 INVENTO'R. HUBERT E. DICKERMAN ATTORNEY.

June 20, 1967 H. E. DICKERMAN 3,326,438

STRIP FEED APPARATUS Filed Oct. 20, 1964 7 Sheets-Sheet ATTORNEY.

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'7 Sheets-Sheet 6 June 20, 1967 STRIP FEED APPARATUS Filed Oct. 20, 1964 INVENTOR. HUBERT E. DICKERMAN ATTORNEY.

June 20, 1967 H. E. DICKERMAN STRIP FEED APPARATUS Filed Oct. 20, 1964 TIL Ilia H" i gj gm 9-- 8 R F: M g :5

7 Sheets-Sheet 7 FIG.9.

INVENTOR. HUBERT E. DlCKERMAN ATTORNEY.

United States Patent 3,326,438 STRIP FEED APPARATUS Hubert E. Dickerrnan, 276 Farmington Road, Longmeadow, Mass. 01106 Filed Get. 20, 1964, Ser. No. 405,212 28 Claims. '(Cl. 226-150) This invention relates to an automatic feeding apparatus of the intermittent reciprocatory type for handling the feeding of predetermined lengths of coil or strip or sheet material to the relatively reciprocating and coacting stamping, blanking, piercing, cutting, punching, or forming dies or other die mechanisms such as multistation progressive dies, of a punch press, although use of the apparatus is not restricted to such as a punch press and may find application in many types of processing machines, such as power shears, sheet metal brakes and other cutting, punching or stamping machines where accurate and variable reciprocable feed strokes are desired.

The invention comprehends a particular construction, arrangement, combination, and relationship of the various elements, components and instrumentalities of a stock feeding apparatus, as exemplified in the following detailed disclosure, wherein the objects defined in the below paragraphs and in the body of the specification will be apparent.

The primary object hereof is to teach a stock feeding apparatus in which the stock retaining and feeding mechanisms are fluid pressure operated, although it is to be understood at the outset that, alternatively, same may be pneumatically or air operated, all Wherewith successive predetermined lengths of coil or strip or sheet material may be fed in a step-by-step manner to an operating area of a work performing machine having relatively movable coacting parts for stamping, drawing, forming, cutting off and/ or performing other work operations.

One general object is to provide an automatic intermittent feed mechanism for accurately feeding stock in se lectively adjustable increments to and between the die members of the work performing machine wherewith, in a cycling manner, the stock is clamped relative to a slide member and unclam-ped relative to a stationary member as the slide member is motivated in a feeding direction and, alternatingly, is unclamped relative to the slide member and clamped relative to the stationary member upon the return non-feeding stroke of the slide member, all operative within an arrangement envisioning stock retaining and feeding mechanisms which are located on opposite sides of a pressure system so arranged as to maintain a constant pressure at one side thereof at all times, thereby to assure against backlash and resultant feeding errors, and to vary the pressure on the other side alternately.

Another chief object is to provide a feed mechanism, as above set forth, wherein, cooperant with and actuated by a pressure and exhaust fluid system, a pair of interrelated clamping or gripping devices is provided, one being designed to mount on a stationary member and to function in a gripping position to hold the stock relative to the stationary member and to the work machine being served, as the other, mounted on a slide member, functions in a non-gripping position preparatory to and during motivation of the slide member rectilinearly in a non-feeding direction, the stock clamping or gripping devices reversing themselves functionwise preparatory to and during the reverse motivation of the slide member in a feeding direction, with the clamping device on the stationary member functioning in a non-gripping position to allow movement of the stock therepast and relative to the stationary member and to the machine as the clamping device on the slide member functions in a gripping position to hold the stock relative thereto and'to carry it forwardly therewith according to the feeding movement of the slide member.

Another object is to provide a work feeding arrangement of the foregoing character comprehending a pair of interrelated work gripping means, one, a retaining gripper, being mounted relative to a mounting member stationarily secured to the machine bed and the other, a feeding gripper, being of which is mounted relative to a slide member, the work gripping means being alternately motivated into work gripping position so that the work may be advanced intermittently in response to the action of a valve subassembly which is operated by and in timed relation with a reciprocating part of the machine being served.

Another object hereof is to provide an. intermittent feed mechanism wherein the working motion or stroke of the reciprocating ram or platen of the machine being served controls the supply of pressure fluid for activating the clamping device on the mounting member on the working stroke of the ram or platen so that the slide member may be retracted without concomitantly moving the Work, and wherein the non-working motion or stroke of the ram 'or platen so controls the supply of pressure. fluid as to activate the clamping device on the slide member and thereby to clamp the work to the feeding side and advance the work in preparation for another ram working stroke, the pressure fluid being supplied alternately to the two clamping devices.

Another object of this invention is to provide a feeding arrangement for work material wherein the Work material is engaged by gripper pads actuated by hydraulic fluid, the flow of which is controlled by a valve means actuated by and in response to the machine to which the feeding arrangement is attached, thereby achieving feeding responses directly correlated to the machine motions.

Still another object hereof is to provide a stock feeding apparatus incorporating improved means for controlling the application of fluid or air pressure to the several operating instrumentalities for effecting their operation in a timed relation.

The feed mechanism serves the broad purpose of advancing strip stock in selectively adjustable increments to the dies and the punch, and broadly comprehends a valve body and mounting assembly upon which a stationary or retaining gripping or clamping device is mounted, and a sliding member assembly upon which a movable or feeding, gripping or clamping device is mounted, said assemblies having an end-to-end relationship via means including a support and slide bar subassembly and a piston shaft subassembly which cooperantly provide for accurate alignment of and coaction between the said devices in a design of maximum simplicity which permits easy assembly and insures reliability of operation, accuracy and speed.

Another object is to provide novel and reliable means for permitting a wide variation of gripper pressure adjustments which may be made easily and quickly so as also to achieve and then maintain any desired gripper release space or clearance between the gripper surfaces of each of the clamping devices.

Our novel feature resides in the teaching of stock contacting gripper surfaces which are curved or radial, thereby to allow for a concentration of the gripping pressure so as to minimize line contact with the stock and therewith to minimize accuracy-destroying influences caused by stock imperfections.

As a further refinement, new and novel means are taught for the gripping or clamping of stock in the form of subassemblies mounted upwardly of, in the case of each of, the stationary and sliding body members, within which subassemblies instrumentalities are disposed having capacities for providing for the adjustment of pressure on the stock, for providing compensating adjustments for varying thicknesses of stock used, and for providing for the adjustment of the release clearance between the gripping components, all desirable in the handling of stock of different qualities, tempers, thicknesses, et al. By such adjustments, when very light, their materials, or materials which cannot be marred or scratched, are to be fed, the gripping pressure can be reduced to the point where the stock is gripped as lightly as though it was being held by an operators thumb and forefinger.

Another salient feature of the invention lies in the fact that the invention reduces considerably the number of costly fluid passages, sequence valves, valve parts and other expensive and troublesome components found in the usual devices of this character. As respects the sliding components of the apparatus, same are made of light material, all so as to make possible much faster feeding speeds, without the usual shocks normally encountered at accelerated operating rates.

Feed apparatus of the general type to which the present invention relates is disclosed in numerous prior patents, but there are myriad objections in connection with the operation thereof. For example, strip stock is sometimes inclined to be somewhat wavy and/ or to have surface imperfections with the result that the coacting rolls or grippers of the clamping means of the reciprocable slide, in its feeding movement, or the coacting rolls or grippers of the clamping means of the stationary member, in retracting movement of said slide, frequently deliver or discharge non-uniform lengths of stock. Such o-bjections are overcome, according to this invention, by fluid-operated clamping means provided in association with the slide member for gripping and clamping the strip stock in feeding movement of the slide member and similar fluid operated means provided for gripping and holding the stock during the retracting movement of the slide member, said means being arranged for instantaneous operation for gripping and clamping strip stock, as well as for releasing same. The gripping means is adapted to adequately clamp the stock, absent rolls or clutches or like parts tending to produce slippage, all to the end that successive sections of stock of uniform length may be fed to the die mechanism.

Regardless of the grade, roughness, evenness or finish of the stock, the apparatus of this invention serves to feed same accurately and free of troublesome and costly jams. The apparatus is especially adapted for handling the lighter gages of stock with improved control, thereby making possible the feeding thereof free of buckling.

The feed incorporates new and novel design features which permit its use over an extremely wide range of applications. For example, by the apparatus, the feed length can be adjusted in extremely fine increments and over a wide range and stock of any practical combination of thickness and width may be accommodated.

Additionally, operating free of any connection to the power shaft of the press, the apparatus may be installed at will on any ordinary type of press, whether it be of mechanical, hydraulic or other type, without any necessity for alteration thereto, and allowing the particularly advantageous feature that it is ideally suited for short or quick runs.

Still another feature worthy of particular notice is the locating of the operating or actuating rod which operates the feed to a situs well out of the way of the work being fed and in a position relative to the apparatus so that its lower terminal is continuously extended into the mechanism thereby to allow safe operation absent the usually omnipresent threat to an operator of catching himself. In this connection, it may be stressed that the actuating rod is located in an out of the way position rearwardly of the mechanism, which feature, additionally to the open side design in that the gripping or clamping devices are open at their front faces without other interrupting devices forwardly thereof, allows a freedom of action to an operator whereby he may freely reach into the gripping components so as easily to feed work thereto or to draw work therefrom and further a freedom of action so as to allow work of any practical widths to be served.

In the apparatus hereof, positive feed control and a reduction of wearing of parts allow for accuracy and consistency of performance, same being of simple design and construction free of complicated mechanism with inherent tendencies to get out of order, with a minimum number of adjustments being required, all of which may be easily and quickly made.

The apparatus offers the additional advantage that it may be successfully applied to the feeding of myriad materials, such as metal of all types, paper, mica, rubber, fibre, plastic, et al., and that it will feed highly polished materials without scratching or marring the finish.

The design of the apparatus is such that it can be mounted on the die set or bolster plate of the press or the like in any position for any style die, with the advantage that, herewith, it is possible to feed into a die from any position, as for example from left to right, right to left, front to back, back to front, or from any angle.

conceivably, two or more of the devices can be used on the same work machine in order to feed separate work pieces from different directions and to perform operations thereupon preliminary to assembly. Further conceivably, a pair of devices, positioned in parallelism, can be used on the same work machine, being so synchronized as to operate unisonly for feeding extra large widths of stock, one apparatus being disposed adjacent each opposite side edge of the width.

All of the above and other ancillary objects, I accomplish by means of such structure and relative arrangements of parts thereof as will fully appear by a perusal of the description below and by various specific features which will be hereinafter set forth.

In the drawings:

FIG. 1 is a view, in top plan, showing the apparatus of the invention according to a preferred form thereof, with the slide member in retracted or rearward position;

FIG. 2 is a view, similar to FIG. 1, partly in section, with the rear and front gripper subassemblies removed, and with the slide member in forward position;

FIG. 3 is a view, in front side elevation, partly in sec- "on, showing the apparatus in the position shown in FIG.

FIG. 4 is a view, in section, on line 44 of FIG. 1;

FIG. 5 is a view, in section, on line 5-5 of FIG. 3;

FIGS. 6 and 7 are enlarged views, in horizontal section, of the spool valve subassembly in operating rod down-spool valve rearward position and operating rod upspool valve forward position respectively; and

FIGS. 8 and 9 are schematic views of the apparatus of the invention, for purposes of illustrating the fluid system within the pressure and pressure and exhaust passages, during the upstroke, when the mechanism is in the actuating rod up (or out)-spool valve forward (or rightward) position and in the actuating rod down (or in)spool valve rearward (or leftward) position respectively.

The presently disclosed embodiment is the preferred form of the invention, but it is to be understood that changes can be made therein by one skilled in the art without departing from the spirit and scope of this disclosure.

The stock feed mechanism is adapted to be mounted upon a work-performing machine which it is intended to serve, such as a punch press, as by attachment to the bolster plate or die set thereof, in order to allow the feeding of strip stock to the punch press dies, the mechanism being operated in synchronism with the operation of a punch mounted upon a ram, said ram suitably mounting means for actuating an operating or actuating rod OR or equivalent actuator, according to the reciprocating movement of the ram. In a punch press, for example, a die mechanism ordinarily includes a lower part secured to the bed of the press and an upper part secured to a vertically-reciprocable ram which, on its down stroke, brings the die parts into coaction for acting on the section of stock fed to the die mechanism, the said upper part being normally reciprocated up and '"down by a connection with the throw or crank of a shaft so that, on each revolution of the shaft, the upper part makes one up and down stroke. Actuating rod OR is interconnected to the said upper part in any suitable way so as to reciprocate therewith and in the process, to constitute the prime mover of the stock-feed mechanism about to be described. On the downstroke of the ram, the slide member (to be described) is retracted. Feeding is accomplished on the upstroke of the rams, as the actuating rod is lifted and the slide member moves forwardly.

Said actuating rod is shown in FIGS. 1, 3, 6 and 9. At the outset, it is to be explained that its lower terminal is continuously disposed within or through and below the confines of the mechanism of the invention wherefor safe operation is assured to the extent that the operator is precluded from catching himself between the actuating rod and the mechanism. A clearance hole in the bed may be provided, vertically below and in alignment with the provided openings in the mechanism, through which the actuating rod is extendable, for accommodating longer-thanaverage stroke presses.

Now, with detailed reference to the drawings, the feed mechanism envisions a valve body and mounting member 10, sometimes referred to hereinafter as the stationary member, having regard for the fact that it is the component of the mechanism rigidly fixed to the work-performing machine to which the mechanism is to feed successive lengths of stock in timed relation with the reciprocating instrumentalities of the machine, and a movable slide member 12 positioned adjacent and at one side edge of the stationary member.

In a suitable recess in the forwardly-facing front edge of the stationary member, the inboard end of a support and slide bar 14 is nested, and secured thereto as by bolting 16, to allow its outboard end to extend outwardly away from the stationary member, thereby to define a supporting medium for slide member 12, same being similarly suitably recessed at its corresponding front edge for nestably receiving the support and slide bar therewithin.

At the outboard extremity of support and slide bar Gi l, a rear guide 18 is fixed thereto, in cross lhead manner, as by bolting 19, said rear guide being likewise suitably recessed at its front edge for nestably receiving therewithin the support and slide bar in supporting manner.

With the support and slide bar thus secured at its opposite extremities, the slide member supported thereby is movable rectilinearly relative thereto between what will be defined, for purposes of orientation, as the rearward position of FIG. 1 and the forward position of FIG. 2. Movement of the slide member from FIG. 1 to FIG. 2 positions will be defined as the feeding or forward direction and from FIG. 2 to FIG. 1 positions will be de fined as the non-feeding or retrograde direction.

The top planar surface of rear guide 18 may be provided with a front-to-rear slideway 20 of inverted T configuration for receiving a pair of roll guides 21, each mounting for rotation a stock roll 22 and a nut 23 threadedly engaged therewith for laterally adjusting and securing the respective roll guide in desired position relative to the rear guide and, more particularly, relative to and at one of the opposite edges of the stock being employed, all in the well known stock guiding manner. The rearwardmost stock roll of the pair thereof will normally be permanently positioned at a situs relative to rear guide 18 so as best to serve its guiding function at the rearwardmost edge of the stock herein identified by a stock line SL in FIGS. 1 and 2, and the forwardmost stock roll of the pair will be adjustably positioned so as best to serve the forwardmost edge of the stock. In such manner, different stock sizes are accommodated.

Forwardly of rear guide 18, an a'djustably-extendable support member 24 is preferentially, but not obligatorily, provided, which may be slidably engaged relative to said rear guide by means of adjusting rods or pins 26 extendable into suitably aligned front-to-rear openings through the rear guide and support members wherewith the support member may be extended distantly of the rear guide, with the top planar surface of the support member being similarly provided with a front-to-rear slideway 27 for accommodating the forwardmost of the roll guide-stock roll-nut subassembly. Set screws 28 will extend upwardly from the lower planar surfaces of the rear guide and support member for purposes of locking the adjusting rods or pins and therewith to hold the support member in predetermined position of adjustment relative to the rear guide, all whereby stock of widths not accommodatable by the rear guide per se may be suitably served.

It may be mentioned here that, conceivably, a pair of mechanisms, one of a right hand and one of a left hand, could be employed unisonly by disposing same on opposite sides of a wide sheet of stock, such arrangement en Visioning the use of a pair of actuating rods OR acting unisonly and suitable metering means for synchronization to insure the requisite cooperant action leading to proper stock feeding.

A cylinder sleeve 30, having .a central opening therethrough, is nestably mounted within a transverselyextending cylinder sleeve bore 32 through slide member 12, the central axis of said bore being coaxial, and in communication, with a transversely-extending piston shaft bore 34 through stationary member 10.

Adjacent the outboard extremity of the cylinder sleeve, an O-ring 36 is nestably seated within a provided annular recess extending inwardly from the outer peripheral cylinder sleeve surface for sealing the cylinder sleeve-cylinder sleeve bore interface.

Within the cylinder sleeve bore and adjacent the inboard end face of the cylinder sleeve, a cylindrical forward slide member bearing 38 is disposed and is sealed relative to the slide member by an O-ring 40 nestably seated in a provided annular recess extending inwardly from the outer peripheral surface of said bearing, thereby to prevent fluid leakage therepast. Similarly, within the cylinder sleeve bore and adjacent the outboard end face of the cylinder sleeve, a cylindrical rearward slide member bearing 42 is disposed and is sealed relative to the slide member by an O-ring 44 seated in a provided annular recess extending inwardly from the outer peripheral surface of said bearing, again for precluding fluid leakage therepast.

Each slide member bearing 38 and 42 is provided with a piston shaft opening therethrough, coaxial and in'communication with a central opening 46 extending through the cylinder sleeve.

Cylinder sleeve central opening 46, the piston shaft openings through forward and rearward slide member bearing 38 and 42 respectively, and piston shaft bore 34 of the stationary member, cooperantly define an extended cylinder bore in which a stationary piston shaft 50 is disposed, in manner such that its inboard extremity extends into piston shaft bore 34 and its outboard extremity extends rearwardly of and beyond slide member 12 to allow an outboard terminal portion 52 to be nestably received in a provided recess in the inboard side face of rear guide 13 to which it is stationarily secured as by bolting 56.

By such just defined means cooperantly with support and slide bar 14, slide member 12 and its supported cylinder sleeve 30 and slide member bearings 38 and 42 are mounted for unitary reciprocating movements rectilinearly in a feeding direction toward and a non-feeding direction away from stationary member 10, between the extreme forward FIG. 2 position and an extreme rear- Ward FIG. 1 position according to the limits defined by a fed adjustment means, subsequently to be described.

As best seen in FIG. 2, the diameter of piston shaft 50 at its outboard portion is greater than the inboard portion diameter. Intermediate these so-called major and minor diameters, an annular piston 60 unitary with the piston shaft is provided and having an O-ring 62 disposed in a provided annular groove in the piston peripheral wall for sealing the piston relative to cylinder sleeve 39.

Such arrangement defines a differential type piston such that, as will appear, in one phase of the operating cycle, when fluid under pressure is supplied to both sides of the piston, the slide member is motivated in one direction, and in another phase of the operating cycle, when fluid under pressure is supplied to one side of the piston and pressure is exhausted from the other side of the piston, the slide member is motivated in an opposite direction.

The outer peripheral surface of that portion of piston shaft 50 receivable in piston shaft bore 34 of member is provided with a plurality of annular lands 64 for accommodating a trio of spaced O-rings 66 serving to seal the piston shaft-valve body and mounting member interface, the lands additionally serving to define a pair of spaced, annular fluid passages each circumscribing the piston shaft, namely a pressure fluid passage 68 and a pressure and exhaut fluid passage 70, which passages communicate through suitable porting in the piston shaft with a pressure fluid passage 72 and a pressure and exhaust fluid passage 74 respectively, said passages 72 and 74 being arranged in spaced parallelism and extending inwardly from the inboard piston shaft end face and being sealed with respect to said end face as by suitable bleeder plugs 76. Pressure fluid passage 72 terminates outboard of piston 60 and communicates with a pressure fluid passage 78 leading outwardly through the piston shaft, and pressure and exhaust fluid passage 74 terminates inboard of piston 60 and communicates with a pressure and exhaust fluid passage 80 similarly leading outwardly through the piston shaft.

A metering or flow resisting and speed controlling means, in the form of a rodlike member 77, is positioned coaxially with and within pressure fluid passage 72, being secured at one extremity to the respective bleeder plug 76 and being seated at its opposite end in and centrally of the terminal end of the pressure fluid passage in such manner as to be disposed centrally of the pressure fluid passage wherefor a restricted fluid flow through the pressure fluid passage is allowed by virtue of the friction offered to the fluid throughout the length of the passage. Same serves, as will appear, to restrict temporarily fluid flow and accordingly, pressure, so as to facilitate the sequencing of the motivation of certain component parts into and out of operative positions and in the controlling of the speed of movement of certain instrumentalities.

Such metering means will be adjustable in the respect that it is readily removable and replaceable by another similar means of greater or lesser diameter, as may be desired.

In assembly, piston shaft 50 is receivable through the openings in the forward and rearward slide bearings and is sealed relative thereto as by O-rings 82 seated in. provided annular recesses in the respective piston shaft openings of each slide bearing.

It is to be recognized, at this juncture in the disclosure, that the cylinder sleeveforward and rearward slide bearings-piston shaft subassembly may be readily and compactly assembled and held securely in situ relative to the slide member as by a retaining ring 83 snapped into a provided retaining ring recess in cylinder sleeve bore 32 adjacent each opposite end thereof, a feature which teaches the elimination of such as tie rods, tie bolts, caps and the like which have encumbered cylinders in prior art structures and have adversely affected their costs.

Within cylinder sleeve 30, the minor diameter of the piston shaft, inboard of piston 60, allows definition of an annular inboard displacement chamber 84 extending toward forward slide member bearing 38, and the major diameter of the piston shaft, outboard of the piston, allows definition of an annular outboard displacement chamber 85 extending toward rearward slide member bearing 42 with the annular inboard displacement chamber being further defined at one end by the relatively large area of the adjacent face of the piston and with the annular outboard displacement chamber being further defined at one end by the relatively small area of the adjacent face of the piston.

Inboard displacement chamber 84 communicates, by means of a ring of equi-spaced ports 86 extending into forward slide member bearing 38 from its outboard end face and communicating with an annular pressure and exhaust fluid passage 88 circumscribing and extending inwardly from the outer peripheral wall of the bearing, with a pressure and exhaust fluid passage 90 extending into and laterally of slide member 12 from the rearward side face thereof and sealed at its outer extremity as by a bleeder plug 92.

Having dealt with the general relationship of the slide and stationary members, attention may be directed to the gripper subassemblies themselves.

The movable or rear feeding gripper subassembly will first be described.

A rear feeding gripper block is positioned upon the upper planar surface of slide member 12, being secured thereto as by doweling 102 and cap screws 104, extendable through suitably oriented dowel openings and tapped openings respectively through the block and slide member for strategically locating and securing said block on and to its respective mounting member. Preferentially, such locating and securing means are disposed as closely adjacent the pressure zone defined by the operating instrumentalities Within the block as is practical, and for reasons which will shortly appear obvious.

The lower portion of the forwardly-facing side of block 100 is provided with a side-to-side open inset 106 to permit easy loading of work to and withdrawal of work from the gripping instrumentalities therewithin, the area generally forwardly of the block being free from interference by other mechanism components.

A vertically-extending, centrally-disposed upper feeding gripper opening through block 100 intersects inset 106 and includes an enlarged upper circular portion 110 and a restricted lower square portion 112, defining an annular shoulder 114 therebetween.

An upper rear feeding gripper pad 130, having a wear resistant carbide insert 131 secured thereto at its' lowermost gripping or clamping surface, is slideably received Within lower portion 112 of the opening and depends from and is threadedly engaged with the lower extremity of a rear feeding gripper adjusting screw 132 extendable through upper portion 110 of the opening, which adjusting screw is spring loaded as by a sleeved spring means 134 seated between an annular flange 136 of the adjusting screw and a cover 140 secured to the block as by bolting 142. The upper extremity of the adjusting screw extends outwardly through a provided opening in said cover for receiving check nuts 146 threadedly engaged upon its shank and at its outermost and uppermost terminal carries a releasing handle 144.

Slide member 12 is provided with a circular verticallyextending lower feeding piston recess 150, extending inwardly from its upper planar face in coaxial alignment with the upper feeding gripper opening of block 100, and intersecting pressure and exhaust fluid passage 90.

Within recess 150, a lower feeding gripper pad or piston is receivable, same including an upper cylindrical rod or stem 152, with a wear resistant carbide insert 153 secured thereto at its uppermost gripping surface, and a lower enlarged piston 154. Rod 152 is circumscribed by an annular gripper bearing 156 seating on the upper planar surface of the piston, which gripper bearing is provided with a ring of equi-spaced recesses extending inwardly and upwardly from its lower planar surface, in each of which recesses a spring means 158 is disposed, and is held in situ against accidental withdrawal by an annular retaining ring 160 which may be snapped into retaining position so as to bear upon a provided shoulder on the gripper bearing and to seat within a suitable annular recess in the wall of recess 150. Piston 154 is provided with an annular recess in its outer peripheral surface, in which recess an O-ring 162 is seated to provide a tight seal between the piston-slide member interface and to preclude leakage of pressure and exhaust fluid therepast from pressure and exhaust fluid passage 90.

By such arrangement, feeding gripper pad or piston 154 will be understood to be powered upwardly to the upper gripping and feeding position by pressure fluid with in pressure and exhaust fluid passage 90 therebelow according to a fixed pressure and thrust predetermined as the maximum which the mechanism will ever be called upon to employ, and to be spring-returned to its lower non-gripping non-feeding position, the travel being a constant under all operating conditions.

Before proceeding with a descriptionof the distinctive operating features of the movable or rear feeding gripper subassenibly, attention is called to the fact that the confronting gripping surfaces of the inserts of the upper and lower feeding gripper pads are each curvilinear so as to minimize line contact with the stock, all whereby the stock is less influencing on the feeding grippers than is the case where the confronting surfaces are flat and parallel to each other, a significant feature when and where stock imperfections are encountered.

Assuming that the lower extremity of adjusting screw 132 is provided with a left hand thread, turning of releasing handle 144 in a clockwise direction will serve to unscrew the adjusting screw from upper feeding gripper pad 130, thereby increasing the space therebetween and inducing a compression of spring means 134. And as the springreturned lower feeding gripper pad or piston has a fixed travel and a fixed pressure, the control means are directed to the upper feeding gripper pad which is so designed as to allow not only a variance of its pressure between a maximum and minimum but also a variance of its clearance with respect to the lower feeding gripper pad, all for adjusting the magnitude of release and for compensating for different thicknesses of stock.

For purposes of illustration, let it be assumed that the vertical travel of lower feeding gripper pad is .040", a constant, and let it be further assumed that stock of a thickness of .050" is positioned between the gripper pads. The operator will first back off check nuts 146 and then rotate releasing handle 144 so that the upper gripping pad 'is motivated downwardly until he has attained an exertion of such pressure as, in his judgment, will suffice for the feeding desired. Such feature allows application of very light pressure, where light delicate stocks may be employed. For example, in the event of the use of such as a work piece of nickel-silver, a mere kissing of the stock may be desirable. Contrariwise, at the other extreme, a pressure of as much as 400-500 p.s.i. can be induced. With the correct pressure exerted upon the stock, check nuts 146 are then turned down to a point where there is a spacing of about .020" between the lower face of the lowermost thereof and the upper planar surface of cover 140. When the lower gripping pad drops downwardly its stroke of .040" and when the screw drops its allowed .020, a release clearance of .020" is obtained. Such adjustment feature allows any practical variance to suit the conditions of stock thickness of any specific case and to provide any desired gripping pressure, and offers the additional advantage that whatever the setting, the pressure will be constant at all moments of each stroke.

To obtain a quick control or more instantaneous grip, the operator might adjust the upper feeding gripper pad at say .035, wherefore only .005" of articulation of the gripper pads will change the same from releasing to gripping positions.

For quick release purposes, as when the apparatus is operative and it is desired to remove the stock, the releasing handle need only be turned down so as to close the gap between the gripper pads. With the gap so closed, releasing handle rotation is continued so as further to compress spring means 134 and to cause the adjusting screw and upper rear feeding gripper pad to be raised, all whereby the stock may be released from the gap, albeit the lower feeding gripped pad may be in upper position.

The stationary or front stock retaining gripper subassembly of the feed mechanism will now be delineated in detail.

A front stock retaining gripper block is positioned upon the upper planar surface of stationary member 10, being secured thereto as by doweling 182 and cap screws 184 extendable through suitable aligned dowel openings and tapped openings respectively through the block and member 10, preferably as closely adjacent the pressure zone as practicality will permit.

As with rear stock retaining gripper block 100, block 180 is provided with an inset 186 at the lower portion of its forwardly-facing side to permit ready access to the gripping devices.

A vertically-extending centrally-disposed upper stock retaining gripper opening 190 through block 180 intersects inset 186 and is adapted to snugly receive an upper stock retaining gripper pad 192, having a wear resistant carbide insert 193 secured thereto at its lowermost gripping surface, which gripper pad supports the lower extremity of a front gripper adjusting screw 194, which screw is spring loaded by a front gripper pressure spring means 196 circumscribing said screw and seated within the opening between an annular flange 198 suitably provided upon the screw and a cover 200 secured to the block as by bolting 202. The upper extremity of the adjusting screw extends outwardly through a suitable opening in the cover for receiving check nuts 206 threadedly engaged upon its shank and at its outermost terminal carries a nut 204threadedly engaged therewith and pinned thereto as by a pin 205.

Valve body and mounting or stationary member 10 is provided with an annular vertically-disposed lower stock retaining piston opening 210 extending therethrough in coaxial alignment with opening 190 through the block, which opening is restricted in its upper portion and enlarged in its lower portion to define a downwardly-facing annular shoulder therebetween.

The restricted upper portion of opening 210 receives the uppermost rod or stem 212 of a lower stock retaining gripper pad of piston 216 with a wear resistant carbide insert 213 secured thereto at its upper most gripping surface, which rod or stem is suitably grooved to accommodate an O-ring 218 for sealing the interface between the rod and the wall of the upper portion of the opening.

The enlarged lower portion of opening 210 receives piston 216, same having a unitary lower rod or stem 214 of a certain diameter therebelow and a unitary upper rod or stem 215 of a diameter less than said certain diameter thereabove and connecting with uppermost rod 212, which piston is suitably sealed relative to the enlarged lower portion of opening 210, as by an O-ring 220 seated in a provided annular recess in its peripheral wall.

As will appear, the piston and its attached rods function as a diiferential type piston, the upper face of the piston presenting a relatively larger area for the action of 1 1 fluid pressure thereagainst than the lower face of the piston.

Lower rod 214 of the lower stock retaining gripper pad or piston is circumscribed by an annular piston retainer 222, seated within opening 210 and sealed relative thereto as by an O-ring 224 seated in a suitable annular recess in its outer peripheral wall, lower rod 214 of said lower stock retaining gripper pad being sealed relative to the piston retainer as by an O-ring 226.

The lower extremity of the lower stock retaining gripper pad is spaced upwardly of an annular spacer seat 228 nested within opening 210 and held in situ as by an annular retainer ring 229 nestably received within a recess in the wall of the opening.

As with the movable or rear feeding gripper subassembly, the confronting surface of the inserts of the stock retaining gripping pads are each curvilinear for minimizing line contact with the stock.

As will appear, the lower stock retaining gripper pad is fluid operated and has a fixed travel and a fixed pressure. The upper stock retaining gripper pad is so designed as to allow a variance of its pressure between a maximum and minimum and further a variance of its clearance with the lower stock retaining gripper pad, all for adjusting the magnitude of release and for compensating for different thicknesses of stock.

Adjustment for pressure control and compensating adjustment for stock thickness and the releasing of the upper stock retaining gripper pad is essentially the same as in the case of the rear feeding gripper subassembly, except that herein, lighter springs are preferentially employed for the reason that the greater pressures are not requisite, there being merely holding and no feeding of stock herewith. Further herein, the provision of a releasing handle may be omitted, a nut with cross pin being substituted therefor, same being capable of being adjusted as by application of a wrench thereto as, once adjusted and set up, the subassembly does not call for changes in normal operation.

Valve body and mounting member is provided with a transversely-extending pressure and exhaust fluid passage 230 which is plugged at one terminus as by a bleeder plug 232 and intersects annular pressure and exhaust fluid passage 70 circumscribing piston shaft 50, which passage 70 is ported to allow communication with pressure and exhaust fluid passage 74 extending through the piston shaft, as aforedescribed. Pressure and exhaust fluid. passage 23!) additionally intersects lower retaining piston opening 210. Upper rod 215 of lower stock retaining piston 216 is of such diameter at the plane of the intersection as to define an annular displacement chamber 234 therearound, which chamber communicates with passage 230. The opposite terminus of passage 230 will be observed to define a port leading, in communicating manner, to a spool valve opening 250, subsequently to be referred to in greater detail. On the opposite side of the wall of opening 250 and offset relative to the longitudinal axis of passage 230, an exhaust fluid passage 231 extends through valve body and mounting member 10, one terminus of which defines a port leading, in communicating manner, from opening 250 and the opposite terminus of which is connected as by an exhaust outlet fitting 236 to an exhaust conduit 238 in communication with a tank (not shown), which conduit and fitting are secured to stationary member 10 as by a nut 239 or equivalent means.

Valve body and mounting member 10 is also provided with a transversely-extending pressure fluid passage 240 which, at one terminus, intersects annular pressure fluid passage 68 circumscribing piston shaft 50, which passage 68 is ported to allow communication with pressure fluid passage 72 extending through the piston shift, as aforementioned. Pressure fluid passage 240 additionally intersects lower st-ock retaining piston opening 210, Lower rod 214 is of such diameter at the plane of the intersection as to define an annular displacement chamber 244 therearound, which chamber communicates with passage 240. Pressure fluid passage 240 also intersects opening 250 defining ports at the points of juncture and continues to its opposite terminus Where it is connected as by a pressure inlet fitting 246 to a pressure conduit 248 in communication with a pump and accumulator (not shown) interconnected with the tank, which fitting and conduit are secured to stationary member 10 as by a nut 249 or equivalent means.

Further provided is an annular recess 245, extending inwardly from and circumscribing the wall of opening 250 and intersecting passage 240 at opposite sides of opening 250 whereby, as will appear, continuous fluid pressure is allowed to flow through said passage 240 irrespective of the positioning of the valving means now to be described, and further whereby the so-called pressure side of the system is under pressure at all cycle moments.

With special reference to FIGS. 6 and 7, the aforementioned spool valve opening 250 extends through valve body and mounting member 10 in spaced parallelism with piston shaft bore 34 for the accommodation therewithin of the spool valve subassembly constituted by components delineated in the next paragraphs.

A cylindrical spool valve actuator 252 is slidably receivable within opening 250 adjacent its inboard end and is secured therewithin by an endmost retaining ring 254 snapped into nesting position in a provided recess in the opening wall. Rotating movement of the actuator, as it slides between its rearward, FIG. 6, position and its forward, FIG. 7, position, is precluded as by a dowel 256 or the like extending transversely through a suitable opening in the actuator and having a free extremity extendable outwardly thereof and slidable in a broached keyway 258 in the spool valve opening wall.

A vertically-extending actuating rod opening 260 extends through the stationary member and intersects an elongated slot 261 in the actuator, whereby actuating rod OR may be reciprocated so as to extend downwardly therethrough, as shown in FIG. 6.

A spool actuator roll 262 having hubs 264 is rotatably mounted within the actuator by means of a dowel 266 extendable through an opening through the roll and hubs and journalled in the actuator.

Rearwardly of slot 261, the actuator peripheral wall is provided with an annular recess in which an O-ring 268 is seated to provide a suitable seal between the actuator-stationary member interface.

Rearwardly of the actuator, a spool valve 270 is slidably receivable within the spool valve opening and is biased in a forward or leftward direction by a spool valve spring 272 receivable within a central opening extending into the spool valve from the outboard end face thereof, being biased in the opposite rearward or rightward direction by the spool valve actuator bearing upon the inboard end face thereof.

The spool valve is of the two-position type having a pair of unitary annular valved ends or lands 271 at opposite ends of a central valve stem for functioning cooperatively and in seriatim in valving or sealing manner with the ports of pressure and exhaust fluid passage 230 and exhaust fluid passage 231 and the ports of pressure fluid passage 240, said lands being of enlarged configuration with respect to the central valve stem in manner to define an annular inwardly extending recess 284 in the outer valve periphery.

Recess 284 allows definition of an annular fluid passage 286 communicating with both sides of passage 240, when the valve is disposed in a forward or rightward first position, as shown in FIG. 7, and with passages 230 and 231, when the valve is disposed in a rearward or leftward second position, as shown in FIG.

A spool valve end plug 276 is nestably receivable within opening 250 outboard of spool valve 270 and is provided with an inboard end 278 of restricted diameter for 13 nesting relationship within spring 272. An O-ring 280 is nested within a groove in the outer peripheral surface of the end plug to provide a seal between the end plugstationary member interface.

A strategically positioned recess 287, extending into stationary member from opening 250 and communicating with exhaust passage 231, may be provided for function as a bleeding vent.

A retaining ring 282 may be snapped into seated position within a provided recess in the wall of opening 250 to preclude end plug withdrawal.

It will be appreciated that a compact spool valve subassembly is thus provided which may be readily assembled relative to the stationary member and held securely in situ as by the said retaining rings.

Additionally, it is to be pointed out that the separation of spool valve and actuator into individual components is such as to insure against the transmittal of any thrust upon the actuator to the spool valve, wherefor the latter ideally serves as a pressure balanced spool valve.

Adjacent a side face of valve body and mounting member 10, a feed length adjusting subassembly is provided, constituted by a feed length adjusting screw 300 having an inboard and extendable through a clearance opening 302 extending through slide member 12 and into threaded engagement with valve body and mounting member 10 Via an opening 304 in which it is receivable, being secured to member 16 as by a set screw 305, and circumscribed at its outboard end by a feed length adjusting member 306 threadedly engaged therewith and secured thereto as by a check nut 303 threadedly engaged with the outboard terminal of the adjusting screw, and additionally by a cushion shock damper or stop means 310 sleeved upon the adjusting screw and receivable into a suitable recess extending inwardly from the inboard end face of the feed length adjusting member, the damper following the adjusting member for serving to receive and cushion the force of the slide member as it abuts thereagainst and is stopped in its non-feeding stroke.

By loosening the check nut and rotating the adjusting member along and relative to the adjusting rod, the allowable feed length can be varied.

A plane 312, fixed to the front face of the slide member, may have a measuring scale 314 delineated thereupon, with a reference mark 316 being strategically located upon the supportbar for purposes of indicating the feed length accordingly as the slide member moves rectilinearly toward the stop means. The feed length setting may be quickly made by reading the scale and making the proper setting on the feed lengthadjusting screw.

Bumper members 318, as shown in FIG. 1, may be so seated in suitable recesses in the inboard side face of slide member 12 as to extend slightly outwardly of the vertical plane of said inboard side face, serving the obvious function of minimizing shock as the slide member is brought into confrontation with stationary member 10 at the completion of its feeding stroke.

A vertically-extending actuating rod opening. 380 is provided through the front feed gripper block and is vertically aligned with actuating rod opening 26!) extending through stationary member 10. A bearing 3-32 is nestably received in opening 330 and similar bearings may be received in the upper and lower portions of opening 260 above and below its intersection with spool valve opening 250, wherewi-th the lower free end portion of actuating rod OR may be snugly received for reciprooable movement relative to said stationary member and front feeding gripper block.

Stationary member 10 is preferentially, though not obligatorily, provided with a series of vertically-extending openings 340 therethrough for purposes of allowing the mounting thereof upon the work machine bed, the openings being aligned and equi-spaced say 2" apart, to allow predetermined incremental movements for effecting a desired positioning of the stationary member relative to the work machine. If other mounting arrangements are desired, other series of openings (not shown), likewise equi-spaced, say /2 and/or 1" apart, could be tapped out of the stationary member.

Dowel openings 342 may also be provided to allow doweling to a plate, when and as same may be desired.

At the pumping means, it is to be understood that an accumulator of conventional design may be provided and incorporating therewithin a vessel for the flow of fluid thereinto. Starting with an empty vessel at atmospheric pressure, same allows the buildup of a head therewi-thin under conditions where the fluid pressure thereabove and the pressure in the connecting pressure conduit 248 between pump and mechanism is developed so as to compress the vessel entrapped air, thereby to allow, during certain periods of flow in the machine cycling, when and as the pump capacity is exceeded, the maintenance at a more constant pressure so as to minimize, if not altogether remove, any back pulsations within the mechanism and/ or within the serving pressure and exhaust conduits.

The cycling of the mechanism, during operational use, will now be described. FIGS. 8 and 9 will be of assistance at this juncture, same being schema-tic representations, with certain liberalities being taken as respects the showing of the referred to components in order best to dramatise the timing sequence.

Accepting that the fluid system envisions two sides, namely a pressure side and an exhaust side, the pressure side is indicated by coding in the form of diagonal lines and the exhaust side is indicated by coding in the form of cross hatched lines.

operationally, valve body and mounting member 10 is mounted relative to a work performing machine in manner such that, as the ram or equivalent member of the machine moves downwardly during its cycle of motion, actuating rod OR, suitably connected thereto for motivation thereby, is correspondingly moved downwardly relative to aligned openings 330 and 260 of the front feeding gripper block and valve body and mounting member respectively, thereby to function as a prime mover and to motivate the feeding mechanism of the invention, the gripping and releasing movements of the retaining and feeding subassemblies being thus correlated to the reciprocating movements of the machine to the end that the confronting gripping devices thereof are alternately motivated into gripping and non-gripping positions in timed relation with the up and down strokes of the actuating rod.

The cycling of the feed apparatus may be generally described, commencing with the operational position, as shown in FIG. 8, making the initial assumption that the leading end of a length of stock or work has been delivered into and through the jaws defined by the confronting gripping surfaces of both the stationary member mounted and slide member mounted gripping devices and additionally -into the operating space between the coacting instrumentalities in the die.

In the FIG. 8 position, actuating rod OR is out or up and slide member 12 is moving forward in feeding direction. Spool actuator roll 262, spool valve actuator 252, and spool valve 270 are in their respective forward or leftward positions under the return force of spring means 272. Spool valve 270 functions to close off exhaust fluid passage'231 lea-ding via exhaust conduit 238 to the tank, thereby allowing maintenance of fluid pressure at both sides of the system and more particularly at both the in board and outboard sides of piston 60,at both the upper and lower sides of lower stock retaining piston 2 16 of the front stock retaining gripper sub-assembly, and at the lower side of lower feeding piston 154 of the rear feeding gripper subassembly, in manner now to be delineated in detail.

With exhaust fluid passage 231 closed ofl", spool valve 270 functions, cooperantly with annular recess 245, to allow passage of pressure fluid, from the pump and accumulator, via pressure conduit 248, into pressure passage 240 to the port thereof at opening 250, wherefrom it is passaged, not only through annular recess 245 and outwardly thereof through the opposite pressure passage port into pressure passage 240, but also through annular fluid passage 286 circumscribing spool valve 270 intermediate its lands 271 and therefrom through the port of and into pressure and exhaust fluid passage 230, all whereby both sides of the fluid pressure system are under the pressure of the fluid and a condition of pressure equilibrium exists.

For purposes of illustration, let it be assumed that a pressure of 400 p.s.i. exists at all points in the fluid system.

In its flow through pressure passage 240, the pressure fluid flows through the intersecting annular pressure fluid passage or lower displacement chamber 244 circumscribing lower stem 214 of lower stock retaining piston 216, and outwardly of pressure passage 24%, the pressure fluid flows into annular passage 68 circumscribing piston shaft 50 and through the porting into pressure fluid passage 72 and outwardly therefrom at the outboard side of piston 60 via passage 78 and into outboard displacement chamber 85.

In its flow through pressure and exhaust passage 230, the pressure fluid flows through the intersecting annular pressure fluid passage or upper displacement chamber 234 circumscribing upper stem 215 of lower stock retaining piston 216, and outwardly of passage 230, the pressure fluid flows into annular passage 70 circumscribing piston shaft 50 and through the porting into pressure and exhaust fluid passage 74 and outwardly therefrom at the inboard side of piston 60 via passage 80 and into inboard displacement chamber '84 and outboard therefrom through the porting in bearing 38 and into pressure and exhaust passage 90 of slide member 12. In its flow through said passage 90, the pressure fluid flows into lower feeding piston recess 150 downwardly of lower feeding piston 154.

The pressure fluid, flowing within pressure passage 240 and pressure and exhaust passage 230 and into the intersecting lower and upper displacement chambers 234 and 244 respectively, is thereby presented to both the respective lower and upper faces of lower stock retaining piston 216 whereby, as with any differential piston having a relatively greater area on its upper face than on its lower face, the piston is motivated in a downward stroke, to the extent determined by lower limit means 228, to its gripper down position out of clamping relationship with its respective related upper stock retaining gripper 192.

By way of exemplification, let it be assumed that the area of the upper face of lower stock retaining piston 216 is .6228 square inches with a .thrust of 249.12 pounds and the area of the lower face is .5522 square inches with a thrust of 220.88 pounds, so that when the 400 p.s.i. pressure is presented to both sides of piston 216, the difference in thrust of 28.24 pounds serves to move the piston downwardly in gripping release direction.

As aforesaid, the pressure fluid flows additionally through passages 72 and 74 within piston shaft 50 and outwardly thereof into the outboard and inboard displacement chambers 85 and 84 respectively at both sides of piston 60. With the inboard portion of piston shaft 50 having a minor diameter and the outboard portion thereof having a major diameter, an area differential is attained by a greater area being presented at the inboard face of piston 60 than at the outboard face. With the fluid pressure on both sides of piston 60 being equal, the differences in the areas allows the rectilinear movement of slide member 12 and its related parts forwardly in feeding direction.

Further by way of exemplification, let it be assumed that the area at the inboard face of piston 60 is .6257 square inch and the area at the outboard face of the piston is .3404 square inch.

As aforesaid, the pressure fluid additionally flows within pressure and exhaust passage 90 of slide member 12 and into lower feeding piston recess 150 below lower feeding piston 154 whereby the piston is motivated in an 15 upward stroke to the extent determined by gripper bearing 156 and retaining ring 160 to its gripper up position.

Further by way of exemplification, let it be assumed that the area of the lower face of lower feeding piston 154 is 1.2227 square inches, wherefore, at 400 p.s.i. pressure, the thrust on the face will be 490.8 pounds so as to motivate the piston upwardly to gripping position.

In the FIG. 9 position, actuating rod OR is down or in so as to shift the components whereby spool actuator roll 262 is urged rearwardly or rightwardly carrying spool valve actuator 252 therewith and moving spool valve 270 rearwardly according, thereby to allow pressure fluid flow from the pump and accumulator through pressure conduit 248 to pressure fluid passage 240, and therefrom to annular recess 245 around spool valve 270 and again into pressure fluid passage 240 and into lower displacement chamber 244 circumscribing stem 214 of lower stock retaining piston 216, and outwardly of pressure fluid passage 240 into annular passage 68 around piston shaft 50 and through the porting into pressure fluid passage 72 and outwardly therefrom at the outboard side of piston 60 via passage 78 and into outboard displacement chamber 85. Thus it is observed that the fluid pressure on the so-called pressure side of the system is continuous.

With exhaust passage 231 now opened by spool valve 270, the pressure is dropped on the so-called exhaust side of the system, wherefor an exhaust condition is established in lower feeding piston recess 150, passage in slide member 12, inboard displacement chamber 84, passages 74 and 70, passage 230, the intersected upper displacement chamber 215 adjacent lower retaining piston 216, and passage 286 circumscribing spool valve 270.

With the fluid pressure dropped on the exhaust side of the system, while continued on the pressure side of the system, lower stock retaining piston 216 is motivated upwardly allowed by the exhausting of upper displacement chamber 234, lower feeding piston 154 is motivated downwardly allowed by the spring return action of spring means 158 upon the exhausting of chamber 150 below piston 154, and slide member 12 is motivated rearwardly in non-feeding direction, it being noted that the thrust at the outboard side of piston 60 and upon rearward bearing 42 is now greater than the thrust at the inboard side of piston 60.

The timing or sequencing of the mechanism will now be set forth in detail.

To insure that lower stock retaining piston 216 is motivated upwardly into gripping position before slide member 12 is motivated rearwardly in non-feeding direction, the flow resisting means, in the form of restricting member 77 disposed within pressure fluid passage 72, functions to allow a preference for the fluid pressure in displacement chamber 244 to articulate piston 216 upwardly into gripping position cooperantly with upper stock retaining gripper 192 for the gripping of the stock before rearward movement of slide member 12 is initiated.

Contemporaneously, under the exhaust condition pertaining thereat, lower feeding piston 154 is released from gripping position cooperantly with upper feeding gripper by the returning action of spring means 158.

Reversely, to insure that lower feeding piston 154 is moved into gripping position cooperantly with the matching upper stock retaining gripper 192 before slide member 12 is motivated forwardly in feeding direction, a time advantage, gained by the thrust difference on the opposite faces of piston 60, is exploited.

Since piston 60 has a greater area at its inboard face than at its outboard face, and because the thrust at the outboard face is 136.16 pounds and the thrust at the inboard face is 250.28 pounds, slide member 12 is allowed to move forwardly only when the thrust at the inboard face of piston 60 has reached and exceeded equilibrium or a ces the 136.16 pounds thrust present on outboard face. Slide member 12 cannot move forwardly until at least 117.5 p.s.i. is developed on the inboard face of piston 60.

In the allowed interval, during the development of thrust on the piston inboard face, lower feeding piston 154 is articulated upwardly to place the feeding grippers in gripping or gripper closed position. The time advantage allows lower feeding piston 154 to be motivated upwardly ahead of the movement of slide member 12 in feeding direction.

Additionally to its function of insuring the desired sequencing, the flow resisting means serves as a speed controller by way of slowing down the reciprocating movement of the slide member throughout its stroke in either direction, resultant from the restricting of the rate of flow of fluid through the high pressure side of the system.

As the slide member commences its stroke, a slight pressure drop is experienced wherefor the flow restricting means serves to preclude the slide member from too fast a movement with a concomitant too fast a drop in pressure, all whereby fluttering is avoided.

Accordingly, the sequential steps in the cyclic movement of the mechanism, responsive to the functioning of operating rod OR, the prime mover, is observed to be as follows:

(1) Operating rod OR makes entry to engage spool actuator roll 262, thereby to move spool valve 270* to rearward or rightward position to open the exhaust side of the fluid pressure system.

(2) The pressure side of the fluid pressure system is constantly under fluid pressure.

(3) Lower retaining piston 216 of the front gripper subassembly is motivated upwardly by the fluid pressure in displacement chamber 244 into gripper up position, and lower feeding piston 154 of the rear gripper subassembly is motivated downwardly by spring means 158 into nongripping position,

(4) Slide member 12 is motivated by fluid pressure in outboard non-feeding direction to the limit determined by feed adjustment damper block 310,

(5) Operating rod OR exits from its engagement with spool actuator roll 262, thereby to allow spool valve 270 to be spring returned to forward or leftward position to close the exhaust side of the system and to impress pressure fluid on both sides of the fluid pressure system,

(6) Lower retaining piston 216 is motivated downwardly by fluid pressure in displacement chamber 234 into non-gripping position,

(7) Lower feeding piston 154 is motivated upwardly by fluid pressure in chamber 150 into clamping position, and

(8) Slide member 12 is motivated by fluid pressure in inboard displacement chamber 84 in feeding direction carrying therewith a certain incremental portion of the stock and causing the stock to be passed through the released front grippers and into the die area.

With the advancement of a new leading end of the stock into the die area for the working thereof upon the next downward ram stroke, the cycle is repeated.

It is to be emphasized here that with one side of the system being continuously under pressure, stabilization of the mechanism is achieved and back lash, leading to feeding errors, is prevented.

And it is to be added further that the mechanism hereof teaches the significant feature of holding displacement values to a minimum thereby not only to avoid the necessity for large capacity pumping means but also to allow faster operating speeds with a minimum of lost time.

As illustrative, the design of annular recess 245, circurrscribing the wall of opening 250, allowing continuous pressure fluid flow through passage 240 and selective pressure fluid flow into passage 286 according to the articulation of spool valve 270, is such that, immediately the respective land 271, under spool valve motivation by spring means 272, commences to clear from its sealing position, a degree of fluid flow into and out of passage 286 is initiated. The clearance develops as a gradually-widening circumferential opening, and in the process, allows a proportionate increasing of the fluid flow. Accordingly, spool valve 270 need to be motivated in unsealing direction only that distance wherewith the defined clearance allows the desired or required pressure fluid flow. Thus, excess articulation of the spool valve can be avoided, there being a need only for such valve articulation as to allow the requisite pressure fluid flow.

Thus it will be appreciated that a strategic locating of passages 240, 230 and 231 with respect to each other and/ or a judicious dimensioning of the width of the lands 271 and/ or the area of annular passage 286 can accommodate to any practical minimizing of spool valve travel wherewith lost time is reduced accordingly, especially with respect to operative moments when the articulating gripper devices are in a neutral phase as they pass each other in their respective ascent or descent, and faster machine operating speeds are accordingly allowed.

Mention is also made of the feature which allows the adjustable positioning of operating rod OR relative to the mechanism and to the work performing machine so that entry thereof, into operative relationship with the spool valve subassembly, can be accomplished at any predetermined moment in the down travel movement of the operating component or crankshaft of the work performing machine between the opposite dead center positions of said crank shaft, all whereby the timing of the mechanism may be varied so as to accommodate to any desired time situa tion at the work performing machine as dictated by the particular type of operation or series of operations being performed during the down stroke.

It will be apparent that myriad combinations of valving situations are attainable according to the dimensioning of various components of the spool valve subassembly, each of which can be further augmented by correlation with the adjustable feature of the restricting means, all to the end that improved timing of operation is achieved.

The invention may be embodied in other specific forms without departing from the essential characteristics thereof. Hence, the present embodiments are to be considered in all respects merely as being illustrative and not as being restrictive, the scope of the invention being indicated by the appended claims rather than by the foregoing description, and all modifications and variations as fall within the meaning and purview and range of equivalency of the appended claims are intended to be embrace-d therein.

What it is desired to claim and secure by Letters Patent of the United States is:

1. In a stock feed apparatus for feeding stock incrementally to a work performing machine in timed relation with the machine operating cycle and comprising, a valve body and mounting member, a piston mounted upon a piston shaft stationarily secured to and. extending outwardly of said valve body and mounting member, a slide member mounting a cylinder with the cylinder being sleeved on said piston for reciprocating movement towards and away from said valve body and mounting member in feeding and non-feeding directions respectively, a fluid pressure operated stock gripping mechanism mounted on said slide member and movable between stock gripping and releasing positions, a fluid pressure operated stock gripping mechanism mounted on said valve body and mounting member and movable between stock gripping and releasing positions, a fluid pressure and exhaust system including interconnecting fluid passage means for conducting alternately pressure fluids to each of said stock gripping mechanisms and to the cylinder on opposite sides of said piston for reciprocating said slide member in nonfeeding direction while the stock gripping mechanism of said valve body and mounting member is in gripping position and the stock gripping mechanism of said slide member is in non-gripping position and pressure fluid to the cylinder on one side of said piston and exhaust fluid from the cylinder on the other side of said piston for reciprocating I 9 said slide member in feeding direction while the stock gripping mechanism of said valve body and mounting member is in non-gripping position and the stock gripping mechanism of said slide member is in gripping position.

2. In stock feed apparatus as set forth in claim 1 including, control means including a spool valve for controlling the alternating application of pressure and exhaust fluids to the cylinder of said slide member and the stock gripping mechanisms of said slide and valve body, and means for supplying fluid under pressure to said control means according to the operating cycle of the work performing machine.

3. In stock feed apparatus for feeding stock incrementally to a work machine in timed relation with the operating cycle of the work machine and comprising, a valve body and mounting member, a piston mounted upon a piston shaft stationarily secured to and extending outwardly of said valve body and mounting member, a cylinder supporting slide member with the cylinder being mounted relative to said piston shaft for reciprocating movement towards and away from said valve body and mounting member in feeding and non-feeding directions respectively, a stock gripping mechanism mounted on said slide member and operated by fluid pressure from a releasing to a gripping position and by spring means from a gripping to a releasing position, a stock gripping mechanism mounted on said valve body and mounting member and operated by fluid pressure between stock gripping and releasing positions, a pressure fluid system including interconnecting fluid passage means for intermittently conducting pressure fluid to and exhaust fluid from each of said stock gripping mechanisms and the cylinder for reciprocating said slide in non-feeding direction while the stock gripping mechanism of said valve body and mounting member is in gripping position and the stock gripping mechanism of said slide member is in non-gripping position and in feeding direction while the stock gripping mechanism of said valve body and mounting member is in nongripping position and the stock gripping mechanism of said slide member is in gripping position.

4. In the stock feed apparatus as set forth in claim 3 including, control means including a spool valve for controlling the alternating application of pressure and exhaust fluids to the cylinder of said slide member and said stock gripping mechanisms, and means for supplying fluid under pressure to said control means according to the operating cycle of the work machine.

5. In a stock feeder, a fixed body, a movable slide, a cylinder fixedly mounted within and movable with said slide, a piston shaft mounted on and projecting from said body and extending through said cylinder and mounting a piston therealong for disposition within said cylinder, said slide being mounted relative to said piston shaft for straight-line reciprocation thereon toward said body in feeding direction and away from said body in non-feeding direction, adjustable feed means for limiting movement of said slide, pressure fluid actuated stock gripping means on each of said body and slide, a valve-operated pressure fluid system including interconnecting fluid passage means for intermittently conducting pressure fluids to and exhaust fluids from said body and the stock gripping means thereof and said slide and the stock gripping means thereof and said cylinder for reciprocating said slide alternately in non-feeding direction while the stock gripping means of said body is in gripping position and the stock gripping means of said slide is in non-gripping position and in feeding direction while the stock gripping means of said body is in non-gripping position and the stock gripping means of said slide is in gripping position.

6. In a stock feeder, a fixed body, a movable slide, a cylinder fixedly mounted within and movable with said slide, a unitary piston and piston shaft mounted on and projecting from said body and extending through said cylinder, said slide being mounted relative to said piston shaft for straight-line reciprocation thereon toward said body in feeding direction and away from said body in non-feeding direction, adjustable feed means for limiting movement of said slide in non-feeding direction, pressure fluid actuated stock gripping means on each of said body and slide, a valve-operated pressure and exhaust fluid system including interconnecting fluid passage means for conducting pressure and exhaust fluids within said fixed body to and from the stock gripping means thereof and within said slide to and from the stock gripping means thereof and within said piston shaft to and from opposite sides of said piston for reciprocating said slide alternately in non-feeding direction while the stock gripping means of said body is in gripping position and the stock gripping means of said slide is in non-gripping position and in feeding direction while the stock gripping means of said body is in non-gripping position and the stock gripping means of said slide is in gripping position.

7. In a stock feeder, a fixed body, a feed head assembly mounted on said body, a movable slide, a feed head assembly mounted on said slide, a cylinder mounted within said slide, a piston and piston shaft mounted relative to said body and projecting outwardly therefrom for straightline reciprocatory movement of said slide and cylinder relative to said piston toward said body in feeding direction and away from said body in non-feeding direction, means for supplying pressure and exhaust fluids to and from the ends of said cylinder on opposite sides of the piston for reciprocating said slide and to said fixed and movable fixed head assemblies for gripping the stock independently of each other during predetermined positions of the reciprocation cycle of said slide.

8. In a stock feeder, a fixed body, a feed head assembly mounted on said body, a movable cylinder-supporting slide, a feed head assembly mounted on said slide, a cylinder mounted within said slide, a piston mounted on a piston shaft, said piston shaft being mounted on said body and projecting outwardly therefrom, said slide and cylinder being mounted on said piston shaft for straightline reciprocatory movement relative thereto toward said body in feeding direction and away from said body in non-feeding direction, means for supplying pressure and exhaust fluids to and from the ends of said cylinder on opposite sides of the piston for reciprocating said slide and to said fixed and movable fixed head assemblies for gripping the stock independently of each other during predetermined positions of the reciprocation cycle of said slide.

9. In the stock feeder as set forth in claim 8, including adjusting means for varying the maximum permissible stroke of said slide relative to said body.

1%. In a stock feed apparatus for feeding stock incre-,

mentally to a work machine in timed relation with the operating cycle of the work machine and comprising, a valve body and mounting member, a piston shaft stationarily secured to and extending outwardly of said valve body and mounting member and mounting a piston therealong, a slide member mounting a cylinder with the cylinder being slidably mounted on said piston shaft for sraight-line reciprocatory movement towards and away from said valve body and mounting member in feeding and non-feeding directions, a stock gripping mechanism mounted on each said slide member and valve body and mounting member and each including fluid pressure op erated means for moving the respective gripping mechanism between stock gripping and releasing positions, a pressure and exhaust fluid system including interconnecting fluid passage means for conducting pressure fluid to and exhaust fluid from each of said stock gripping mechanisms and the cylinder for reciprocating said slide member alternately in non-feeding direction while the stock gripping mechanism of said valve body and mounting member is in gripping position and the stock gripping mechanism of said slide member is in non-gripping position and in feeding direction while the stock gripping mechanism of said valve body and mounting member in non-gripping position and the stock gripping mechanism of said slide member is in gripping position, the area of the piston face on one side of the piston being of lesser dimension that the area of the piston face on the opposite side of the piston for effecting movement of said slide member responsively to the generated thrust on one side overcoming the generated thrust onthe opposite side of the piston.

11. Automatic feed mechanism for power presses and like machines comprising in combination, a stationary base mounting a differential-piston-carrying piston shaft fixed thereto and projecting outwardly therefrom, a rectilinearly reciprocable cylinder-carrying slide with the cylinder there-of being slidable relative to the differential piston for sliding movement of said slide in non-feeding direction away from and in feeding direction toward said base, feed gripping means adapted to grip stock and mounted on said slide, retaining gripping means adapted to grip stock and mounted on said base, a hydraulic system including a pair of hydraulic pressure and exhaust fluidways operatively connecting with the slide cylinder each on an opposite side of the differential piston and each connecting with each of said gripping means and arranged operationally for the alternating motivation of said feed gripping means into stock-gripping position and the concomitant motivation of said retaining gripping means into non-stock-gripping position and motivation of said feed gripping means into non-stock-gripping position and the concomitant motivation of said retaining gripping means into stock-gripping position in timed relationship with the reciprocation of said slide in effecting the automatic intermittent feed of stock to the machine, a restricting means Within one of the fluidways for effecting pausation of said slide at each extreme of its reciprocatory movement during change of the gripping and non-gripping positions of said feed gripping and retaining gripping means.

12. Automatic feed mechanism for power presses and like machines comprising in combination, a mounting body, a slide mounted for reciprocatory movement relative to said body, feed gripping means adapted to grip stock and mounted on said slide for movement therewith, hydraulic means for motivating said feed gripping means into gripping position, spring means for motivating said feed gripping means into non-gripping position, retaining gripping means adapted to grip stock and mounted on said body, hydraulic means for motivating said retaining gripping means into gripping and non-gripping positions, a cylinder mounted within said slide, a stationary shaft mounting a differential type piston and fixed to said body and receiving in sleeved relationship said cylinder for reciprocatory movement of said slide relative to said body, a hydraulic system including a pair of hydraulic fluidways each operatively connecting with said cylinder on opposite sides of the differential piston for alternately supplying a pressure fluid to both sides of the differential piston in motivating said slide in feeding direction to a first position of adjacency with said body and supplying a continued pressure fluid to one side of the differential piston and exhausting the pressure fluid from the other side of the differential piston in motivating said slide in non-feeding direction to a second position away from said slide while alternately opening and closing said feed and retaining gripping means in timed relationship with the reciprocation of said slide, flow restricting means disposed in the fluidway containing the continuous supply of pressure fluid for introducing a preference function for effecting at each extreme of the reciprocatory movement of said slide an interchange of the gripping actions of said feed and retaining gripping means preliminary to the re verse movement of said slide.

13. Automatic feed mechanism for power presses and like machines comprising in combination, a mounting body, a slide mounted for reciprocatory movement relative to said body, feed gripping means adapted to grip stock and mounted on said slide for movement therewith, hydraulic means for motivating said feed gripping means into gripping position, spring means for motivating said feed gripping means into non-gripping position, retaining gripping means adapted to grip stock and mounted on said body, hydraulic means for motivating said retaining gripping means into gripping and nongripping positions, a cylinder mounted within said slide, a stationary shaft mounting a stationary differential type piston and fixed to said body and sleevably receiving said cylinder for reciprocatory movement of said slide relative to said body, a hydraulic system including a pair of fluidways with one fluidway defining a continuous pressure fluidway and one fluidway defining a pressure and exhaust fluidway and each operatively connecting with said cylinder at an opposite side of the piston for the alternating supply of a pressure fluid to both sides of the piston While motivating said slide rectilinearly in a feeding direction to a first position of adjacency with said body and supply of a pressure fluid to one side of the piston and simultaneous exhaust of the pressure fluid from the other side of the piston while motivating said. slide rectilinearly in a non-feeding direction to a second position distantly of said body with the simultaneous alternate supply pressure fluid to said feed gripping and retaining gripping means for cyclically opening and closing cooperantly with said spring means the upper and lower components of the respective feed gripping and retaining gripping means in timed relationship with the alternate reciprocatory movements of said slide for effecting the automatic intermittent feed of stock to the machine being served, and pressure fluid restricting means in the continuous pressure fluid way enabling at each extreme of the reciprocatory movement of said slide an interchange of the gripping actions of said gripping means while said slide is in momentary reversing-reciprocation position and prior to the commencement of its reverse stroke.

14. An hydraulically-operated feed for feeding stock incrementally to and in timed relationship with the Operating cycle of a work-performing machine having a prime mover,

comprising in combination,

a body mounted on the work-performing machine,

a piston shaft stationarily secured to and projecting outwardly from said body,

a differential piston mounted on said piston shaft,

a cylinder-supporting slide with its cylinder being slidably mounted on said piston and reciprocable rectilinearly towards and away from said body in feeding and non-feeding directions respectively,

a stock feeding gripper mechanism mounted on said slide and being shiftable between stock-gripping and stock-releasing positions,

a stock retaining gripper mechanism mounted on said body and being shiftable between stock-gripping and stock-releasing positions,

a valve-operated pressure and exhaust fluid system including pressure and pressure-exhaust fluid passages for alternately conducting pressure fluid to each of said gripper mechanisms and to the cylinder on opposite sides of said piston for reciprocation of said slide in non-feeding direction while the gripper mechanism of said body is in stock-gripping position and the gripper mechanism of said slide is in stockreleasing position and conducting pressure fluid to the cylinder on one side of said piston and exhaust fluid from the cylinder on the other side of said piston for reciprocation of said slide in feeding direction while the gripper mechanism of said body is in stock-releasing position and the gripper mechanism of said slide is in stoclogripping position.

15. In the feed as set forth in claim 14,

said pressure and exhaust fluid system including a pump means connected to spaced pressure and ex- 23 haust ports each extending inwardly from one side of and into said body,

the valve package of said pressure and exhaust system including,

a longitudinal bore in said body intersecting the pressure and exhaust ports,

a valve spool slidable rectilinearly within the bore,

an actuator for actuating the valve spool in one direction responsively to the movement of the prime mover of the Work-performing machine,

a spring for actuating the valve spool in an opposite direction,

the valve spool being disposed intermediate and in tandem with the actuator and spring,

the valve spool being adapted for selective connection and closing between a first position of pressure port opening and exhaust port closing and a second position of pressure port closing and exhaust port opening,

with an annular flow passage circumscribing the valve spool and communicating with the pressure and pressure-exhaust fluid passages of said pressure and exhaust fluid system for the flow of pressure fluid thereto in the first position of the valve spool and communicating with the pressure-exhaust fluid passage of said pressure and exhaust fluid system for the flow of exhaust fluid therefrom in the second position of the valve spool.

16. In the feed as set forth in claim 14,

said pressure and exhaust fluid system including,

speed control means in the pressure fluid passage for throttling the flow of pressure fluid and effecting pausation of said slide at each extreme of its reciprocatory movement during alteration of the stock gripping and stock releasing positions of said stock feeding and stock retaining gripper mechanisms.

17. In the feed as set forth in claim 14, said pressure and exhaust fluid system including,

speed control means in the pressure fluid passage for introducing a preference function for effecting at each extreme of the reciprocatory movement of said slide an interchange of the stock gripping and stock releasing positions of said stock feeding and stock retaining gripper mechanisms preliminary to the reverse movement of said slide.

18. In the feed as set forth in claim 14,

said pressure and exhaust fluid system including,

speed control means in the pressure fluid passage for effecting proper sequencing of the operative movements of said slide with respect to the operative movements of said stock feeding and stock retaining gripper mechanisms.

19. In the feed as forth in claim 14,

said pressure and exhaust fluid system including,

timing means for sequencing movements of said slide with respect to the operative movements of said stock feeding and stock retaining gripper mechanisms.

20. In the feed as set forth in claim 14, including, adjusting means for varying the permissible range of reciprocating stroke of said slide relative to said body.

21. In the feed as set forth in claim 14, including,

the area of the piston face on one side of said differential piston being of lesser dimension than the area of the piston face on the opposite side for effecting movement of said slide responsively to the generated thrust on one side overcoming the generated thrust on the opposite side of said piston.

22. In the feed as set forth in claim 14,

said stock feeding and stock retaining gripper mechanisms each including,

a lower gripper pad having a fixed articulated movement between upper and lower positions as determined by upper and lower stops respectively and an upper gripper pad having a variable articulated movement with associated adjustment means for varying the pressure between the upper and lower gripper pads.

23. In the feed as set forth in claim 14,

said stock feeding and stock retaining gripper mechanisms each including,

a lower gripper pad and an upper gripper pad and adjusting means for providing variation of gripper pressure at the confronting gripper surfaces.

24. In the feed as set forth in claim 14,

said stock feeding and stock retaining gripper mechanisms each including,

a lower gripper pad and an upper gripper pad and means for adjusting the clearance between the confronting gripping surfaces for accommodating stoc of various thicknesses.

25'. In the feed set forth in claim 14,

said stock feeding and stock retaining gripper mechanisms each including,

a lower gripper pad and an upper gripper pad and means for adjusting the releasing clearance between the confronting gripping surfaces.

26. In the feed as set forth in claim 14,

said stock feeding and stock retaining gripper mechanisms each including a lower gripper pad and upper gripper pad being spring and hydraulically powered for positioning between upper and lower stop positions.

27. In the feed as set forth in claim 14,

said stock feeding and stock retaining gripper mechanisms each including,

a lower gripper pad and an upper gripper pad in 0pposition thereto with the confronting stock-contacting surfaces of the opposed gripper pads being radial for concentrating gripping pressure to a substantially line contact.

28. In the feed as set forth in claim 14,

said stock feeding and stock retaining gripper mechanisms each including, lower gripper pad, and upper gripper pad,

means for powering the lower and upper gripper pads into stock gripping position,

means for powering the lower and upper gripper pads into stock releasing position.

References Cited UNITED STATES PATENTS M. HENSON wooo, .IR., Primary Examiner.

R. A. SCHACHER, Assistant Examiner.

Claims (1)

1. 7. IN A STOCK FEEDER, A FIXED BODY, A FEED HEAD ASSEMBLY MOUNTED ON SAID BODY, A MOVABLE SLIDE, A FEED HEAD ASSEMBLY MOUNTED ON SAID SLIDE, A CYLINDER MOUNTED WITHIN SAID SLIDE, A PISTON AND PISTON SHAFT MOUNTED RELATIVE TO SAID BODY AND PROJECTING OUTWARDLY THEREFROM FOR STRAIGHTLINE RECIPROCATORY MOVEMENT OF SAID SLIDE AND CYLINDER RELATIVE TO SAID PISTON TOWARD SAID BODY IN FEEDING DIRECTION AND AWAY FROM SAID BODY IN NON-FEEDING DIRECTION, MEANS FOR SUPPLYING PRESSURE AND EXHAUST FLUIDS TO AND FROM THE ENDS OF SAID CYLINDER ON OPPOSITE SIDES OF THE PISTON FOR RECIPROCATING SAID SLIDE AND TO SAID FIXED AND MOVABLE FIXED HEAD ASSEMBLIES FOR GRIPPING THE STOCK INDEPENDENTLY OF EACH OTHER DURING PREDETERMINED POSITIONS OF THE RECIPROCATION CYCLE OF SAID SLIDE.

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