US2490778A - Compound fluid ram - Google Patents

Description

Dec. 13, 1949 B. o. BURRITT COMPOUND FLUID RAM 2 sheets-sheet 1 Filed March ll, 1946 ANNTQ Dec. 13, 194

B. O. BURRITT COMPOUND FLUID RAM 2 sheets-shamr 2 Filed March 11, 1946 I INVENTOR. ,Bar/eZ? 0. ,Ba rra'z.

Patented Dec. 13, 1949 COMPOUND FLUID RAM Burnell 0. Burritt, Detroit, Mich., assignor to Ralph N. Davis, Carl Schwartz, John Johansen, and Paul Halling, copartners, doing business as Craftsman Tool and Die Company, Detroit, Mich., a copartnership Application March 11, 1946, Serial No. 653,553

(cl. 1er-3s).

3 Claims.

This invention relates generally to fluid pressure actuated devices and is especially adaptable, among other uses, for hydraulic ram mechanisms for urging a tool against or through a workpiece.

Primary objects of this invention are to provide a novel and improved ram mechanism of the class described; to provide in such a mechanism novel means for guiding the tool-carrying portion; to provide means whereby the rate of movement of the tool-carrying member may be controlled; to provide in such a Huid-actuated ram means a construction whereby any leakage flow of iluid past the movable members is conducted back to the source of supply; to provide a multiple piston arrangement whereby greater force may be exerted upon the carried tool with a small over-all dimension; to provide a ram mechanism which carries a plurality of tools whereby a rst tool can engage the work and thereafter a second tool can engage the work; and to provide a small, compact ram mechanism which can be suitably arranged in multiple banks for performing a multiplicity of simultaneous or sequence operations on a member or workpiece by means of inexpensive jigs, thereby eliminating the cost of larger equipment and costly dies. Other objects will be apparent from the specification, drawings, and appended claims.

In the drawings, in which like numerals are used to designate like parts in the several views throughout,

Fig. l is a View in central vertical cross section of a ram mechanism embodying the invention;

Fig. 2 is a view in end elevation showing the device of Fig. 1;

Fig. 3 is a View in side elevation of the ram mechanism shown in Fig. l mounted on a supporting member for punching a workpiece, the workpiece and its carrying portion being shown in cross section;

Fig. 4 is a view in side elevation of a ram mechanism similar to that of Fig. l, showing an adapter plate `carried thereby arranged for drilling; and,

Fig. 5 is a view in side elevation showing the ram mechanism similar to that of Figs. 1v and 4, but having an adapter plate arranged `for milling. Y

Referring to therdrawings, theY numeral I desgnates generally a platelike base member hav- Y 2 ing anV integral laterally extending, platelike member 2 having an aperture 3 extending therethrough, the longitudinal center line of which extends substantially` parallel to the top face-4 ofthe base member I. The member I has a plurality of countersunk holes 5 which receive suitable cap vscrews for securing the base member I to a support 6 when it is desired to rigidly Ahold the plate member IV with respect to the support 6. As shown in Fig. 3 it is sometimes desirable to permit Ymovement between the platelike member. I and the support 6, and in this event no cap screws are used vin the apertures 5, the platelikemember I being carried by the support in slide members I extending over flanges 8 of base member I. The slide members 1 are suitably secured'to the support 6 by stud bolts 9. In this construction a strap member Ill is secured to one end portion I2 of the base member ibystudfbolts ILL A stud screw It screwthreaded into the` support 6 extends through an aperture Yin thestrap member II) and therebeyond. i Preferably vthe stud screw I5 is lockedin the support byV means of a nut I8. A helical coil compression spring 20 concentric with screw I6 has one end portion abutting the strap member Ill and its vother end portion abutting the under side of a pair of locking nuts 22 secured to the portion of the stud screw f I6 extending beyond the strap member I0. The spring 2d acts against the strap member I0 and therethrough to urge the base member I in a downward direction asseen in Fig. 3,-to`cause. the tool 24 carried by a laterally extending portion 26 of the base member I to be moved out of engagement with the workpiece,r 28. Movement of the base member I bythe spring 20 is limited by engagement of the strap member- I0 with a second pair of locking nuts 3l) carried by the stud screw I6 intermediate the nuts YI8 and the strap member I0. -V Referring again toFig. l the ram mechanism comprises a rst cylinder member 32, a piston member 34, an outer sleeve, and an adapter plate 38 for carrying a tool, such as tool 39 of Fig-3. .The cylinder member-32 has a normal diameter portion 40 and a reduced diameter portion 42 which substantially conforms to the aperture 3V and isreceived therein. .A shoulder 44 formed at the intersection ofthe normal diameter 3 portion 40 with the reduced diameter portion 42 seats against the front face 45 of the laterally extending portion 2 of the b-ase member The reduced diameter portion 42 extends through and beyond the opposite or rear face 41 of the laterally extending portion 2 and is externally screwthreaded for reception of an internally screwthreaded nut 48 which abuts the face 41 for clamping shoulder 44 of the cylinder member 32 tightly against the face 46 whereby member 32 is rigidly carried by the laterally extending portion 2. The portion of the cylinder member 32 extending away from the portion 2 on the side of face 46 has a piston chamber 50 opening outwardly through the extending end portion 52 of the cylinder member 32 in which the head 54Y of the piston 34 has a piston-tight t. A hollow stem portion 55 of piston 34extends longitudinally I aperture 64 has its head portion engaging the aperture plate 60 and its other end portion screwthreaded into the adapter plate A3i3ior holding the adapter plate 38 rigid to thepiston 34 and the plate 60 against shoulder 50.

The outer sleeve 36 telescopically surrounds the cylinder member 32 and has one end surface 61 thereof adapted to abut the face 46 of the laterally extending portion 2 ofthe base member I, thereby limiting its movement in a tool retracting or one direction on the cylinder member 32. The other end 68 of the outer sleeve 36 extends beyond the extending portion-52 ofthe cylinder -member 32 and is received about the cylindrical projecting portion 51 of the adapter plate 38.` The portion 68 is preferably secured'to the plate member or adapter plate 38 in a duid-tight manner, such as by welding, as at 10. The cylinder member 32 has a longitudinally extending circumferentially recessed portion 12 which, in part, is coextensive with the piston chamber 50,' and, at all normal positions, the sleeve 36 surrounds portion 12 to form a chamber 14. Radially extending passageways positioned at spaced points in `member 32 communicatively connect the piston chamber 50 with the chamber 14 for fluid `ow therebetween.

`The stem portion 56 adjacent the cylinder-'member portion 52 is guided within an annular mem'- ber 18 having its external surface substantially tting the inner surface of the piston chamber 50 and having its inner surface'substantially fitting the external surface of the piston stem portion 56. Snap rings 80, tting in recesses in the wall of chamber 50, hold the member 18 in xed position. Undesired uid flow between the cylinder member 32 and annular member 18 is prevented by a piston ring or gasket 82'which is received within a circumferential recess of the annular member 18. The cylindrical portion 51 of adapter plate 38, the adjacent portion ofthe outer sleeve 36, the extending end Wall of the cylinder member 32, and the annular member 18 cooperate together to provide an expansible contractible chamber 84 which at all timesis in fluid-flow communication with the 'hollow interior of the stem portion 56 by means of radially 4 extending passageways 86 through the wall of the piston stem portion 56. These passageways 86 are so positioned longitudinally of the stem 56 that they remain at all times on the side of the annular member 'E8 adjacent the chamber 84.

A radially extending passageway 88 extends through the 'side wall of the piston stem portion 56 and communicatively connects, for fluid ilow, the hollow interior of the stem portion 56 with an annular chamber 96 formed around portion 56 within the piston chamber 5t intermediate the annular member 18 and the piston head portion 54. The passageway 36 is so positioned longitudinally of the stem portion 5S that, with the surface 8l of the outer sleeve 3@ in engagement with the surface fit, the passageway 83, at least partially, maintains communication between the chamber 90 and the hollow interior of the stem portion 5S. Upon predetermined movement of the'adapter 3% away from the cylinder member 32,

. the passageway 38 will pass into the annular member 18 thereby co-operating with the stem portion 56 in the manner of a slide valve to stop huid-flow through the passageway 08. The cylinder member 32 on either side of the recess portion 12 has outwardly opening circumferentially extending recesses 92 which receive piston rings or packing to resist undesired ud-iiow thereby between the cylinder member 32 and the outer sleeve 36.

Fluid under pressure pumped from a suitable source of supply (not shown) is conducted by means of a conduit S3, passageway 93l1 in the rotatable portion 94 of valve 9|, and conduit 95, to a passageway 36 extending concentrically and longitudinally of the cylinder member 32 and opening through an end wall 91 into a pressure chamber 5| formed in chamber 50 intermediate the wall 91 and piston head 54. A second longitudinally extending passageway 9B extends substantially parallel with the passageway 95 and opens through a radial passage 98. Passageway 38 also opens into a circumferentially arranged annular chamber 99. The laterally extending portion 2 of the base member has a passageway |00 which aligns with the circumferential annular chamber 99 and is screwthreaded for reception of a discharge conduit |04 for conducting fluid from the passageway B8. Conduit |04 is connected to valve si and, by means of passageway Hille in valve portion 94, to a return con' duit |05 which may open into the source of uid from which the conduit 93 is supplied. A third conduit |06 communicatively connects the valve 9| with the passageway 96 so that when the valve portion 94 is moved to a second position a valve pas sageway E963 in portion 9e will communicatively connect conduits 93 and |06 for ow of pressure fluid to chambers 14 and 00. The second position of valve portion 84 also aligns valve passageway 35a with conduits 95 and |05 for fluid flow from chambers 5| and 84 to the source of uid supply. The valve portion 94 may be rotated from the first position, as shown in Fig. 1. to the said second position by handle it?? which is engageable with stops |538 and |09 to limit rotational movement so that the proper passageway 93a. |04a or |05, |06a will be aligned with conduits 93, 95 and |04, |05 or 95, |05 andr93, |33 as described above for the shown and the said second position of the valve portion 94. Lines 93 and 05 may, of course, be associated with any suitable supply system, utilizing pumps or other devices having characteristics suited to the work.

A guide dowel pin |0`carried by the adapter plate 38 extends'toward and is received within a guide aperture I II of the base member I. In the modification shown in Fig. 5 two such pins IIO and apertures I|I are illustrated. The pins |I and apertures III -cooperate with the telescopic arrangement of sleeve 36 with cylinder member 32 to provide guiding means for the adapter 38 which accurately holds the adapter 38 against al1 undesired movement so that the tool 39 may do accurate work on the workpiece 28.

The adapter plate 38 may be arranged to carry =a variety of tools for operating on a workpiece. In Fig. 3 there is shown a set of tools 24 and 39 for forming and punching the workpiece 28. In Fig. 4 the adapter plate 38 is arranged to carry multiple drill spindles II2 which may be rotated by a motor I I3 (electric, uid or other type) carried by the adapter plate 38'. In Fig. 5 the adapter plate 38 is shown as carrying a milling cutter |I4 which may be rotated or powered by a similar motor ||5 also carried by the adapter plate 38". In the arrangements shown in Figs. 4 and 5 it is often desirable to provide means whereby the adapter plates 38 and 38 are moved relatively slowly and with less force until the drill carried by the multiple drill spindle II2 or the milling cutter wheels carried by the milling cutter II4 are in engagement with the work and thereafter to apply the full fluid force to hold the drills and milling cutters against the workpiece. rate of change of speed and force exerted by the ram is provided for by regulating the rate of fluid flow through conduit |04 by means of a valve member I I6 carried within the plate-like member 2' and cooperable with a valve seat |I'|. valve member ||6 is urged yaway from seat I|1 and into engagement with a cam track I |8 of cam member I9 by a spring |20 concentric with member I I6 and held between valve member flange |2| andthe bottom wall of the valve chamber |22. The member II9 is reciprocally movable within an aperture |23 extending through the member 2 and a threaded end portion |24 received within an aperture |25 of a laterally extending portion |26 of the sleeve 36. Pairs of nuts I2'| and |28 threaded onto portion |24 provide spaced abutments engageable by portion |26 for longitudinal movement of the member II9. These may be arranged as shown to provide lost motion or may clamp the member |I9 tightly to the sleeve portion |26. By changing the contour of cam track I I8 other desired rates of movement may be provided for, it being understood, of course, that junctions between successive tract portions are sloped sufficiently to permit camming movements of the stem of valve I I6. This restriction of fluidflow (which, preferably, is utilized only in the presence of relatively low pressures in the inlet line 93), to the conduit |04 acts to set up a back pressure against the piston head 54 to effectively reduce the force exerted by the incoming fluid pressure through the passageway 96 and acting intermediate the piston head '54 and wall 91 for moving the tools -against the workpiece.

A U-shaped guard ring |30 is carried by the base member I and its laterally extending portion 2 by means of screws |32 so that as the end of the outer sleeve 36 moves away from the surface 46, no foreign matter can drop into the space vacated by the outer sleeve 36 and upon return movement of the sleeve .36 into engagement with the surface 46 be crushed therein and cause damage.

The operation of the hydraulic or fluid-pressure ram is as follows: Fluid pressure pumped This The

forced through conduit 93 and controlled by valve 9| to ow either into conduit 95 or |06. In the position shown fluid flows through passage- Way 93a, conduit 95, passageway 96, and into the chamber 5I intermediate the end wall 91 and the piston head 54. Fluid also flows through the apertures 62 of the apertured plate 60 through the hollow stem 56 and through the radial passageway 86 into the chamber 84. With the elements positioned as shown in Fig. l, iiuid also flows through the radial passageway 88 into the chamber 99 and therefrom to the radial passageway 'I5 into the chamber 14, out through the passageway 65, conduit |04, passageway |54a and the conduit |05. Normally, the chambers 55 and 84 will be lled with iiuid and as fluid is supplied by conduit 93 a pressure builds up in chambers 5I and 84 in a direction to force the adapter plate 38 outward from the base portion I. A certain amount of uid flows through passageway 88 thus increasing the pressure in chamber 95 at the same time the pressures are building up in chamber 5| and 84 thereby creating a back-pressure against the back side of the piston head 54, which tends to oppose the elect of the fluid pressure in chamber 5I. Simultaneously with the foregoing, some fluid flows outwardly from the chamber through the passageway '|6, into the chamber "I4, and therefrom through the passageway 96 into the conduit |04. As soon as the piston 34 has moved outwardly a short distance, the passageway 88 is closed because it then registers with the annular member 'I3 and no more uid flows from the stem portion 55 into the chamber 99.

It will now be noted that fluid pressure in the chamber 5I acts in effect on the full area of the head 54 although some of it may act down through the hollow stem against the bottom or" the recess 55 of the adapter 38. In addition, the fluid pressure acts on the remainder of the raised portion 5l of the adapter plate 38 and has an effective acting area in the form of an annulus (equal in area to the area of the face of boss 5l less the area of the reduced portion 58 of piston 34) which supplements the force acting upon the piston head 54. To move the tool away from the workpiece the handle Ill'l of valve 9| is moved into engagement with stop |09 which rotates Avalve portion 94 to bring passageway |95a into alignment with conduits 95 and |65 and passageway |069 into alignment with conduits 93 and |06. Fluid under pressure from conduit 93 flows through passageway |669, conduit |06, passageway 98, chamber "I4, and passageways 'I6 to chamber 90 to exert a force on piston head 54; passageway 88 being closed by member 18. Chambers 84 and 5| at this time are open to'tank through passageways 96 and |05a and conduits 95 and |65 so that fluid in chambers 5| and 84, displaced by the tool retracting movement of piston 34 and adapter 38, will flow back to the tank. It should be noted that ow of fluid from passageway 98 to the supply source flows through 5 conduit |04 which may be provided with the restrictor valve ||6; however, fluid flow to passageway 98 from the source of supply is through conduit |06 which has no such restrictor.

At or near the conclusion of the retracting stroke, stem 55 exposes port 88, completing a by-pass connection around chamber 99, leading to the tank, and extending through the bore of stem 55, chamber 5I, and passageway 95. It will be appreciated that this by-pass connection lfrom a suitable source of supply (not shown) is 75 governs the pressure atwhich the adapter 38 is retained-in retracted position, thereby-reducing the pressure demand on the source during stand'- by periods and also reducing power requirements. Further, and, importantly, this ley-pass connection permits a continuous circulation of oil from the sour-ce throughout the device. This continuous circulation, as will be understood, cleanses the oil.

Referring to the apparatus as shown in Fig. 3, the adapter plate 38 carrying the tool will, be moved relative to the supporting plate l l into engagement with the workpiece 2B as described hereinbefore` Subsequent to engagement with the workpiece 2 the reaction force exerted by the tool 39 on the workpiece 2li-'will overcome the opposing force of the spring 20 and the plate member I will bodily slide in the ways or slide members i whereby the tool Est-'caliied by the lmember portion 2a will move into-engagement with the workpiece 23, and in the instanceshown in the subject figure will cause the tool- Z to pierce the workpiece 2g. SubsequentV to release of pressure in the conduit 93, the spring 263 will act against the strap member lll forcing the plate member l downwardly and the tool 24 out oi the workpiece 28.

rlhis invention provides an improved ram mechanism simple and economical of construction, which construction provides an` eiective piston area greater than the vcross-sectional area oi the ram cylinder whereby greater forces may be exerted by the ram; means whereby the rate or" movement of the tools may be controlled as well as the force exerted by the tools on the workpiece; a simple, small, compact ram .which may be used in multiple banks, thereby doing away with costly cam dies, and which may be operated from a common uuid pressuresupply line along with other mechanismI` without requiring special individual iluid pressureY control vvalves otherwise necessary so that the tools do not exert too great a force on the workpiece or impinge thereon with a too great striking force.

What is claimed and is desired4 Ato be secured by United States Letters Patent is as follows:

i. In a pressure-operated ram mechanism,l a plate-like base having a platelike portion extending laterally thereof, said portion having an aperture opening through one face thereof, a cylindrical member having a. portion held within said aperture, said cylindrical member having a piston chamber therein opening through one end wall thereof and having a pair of passageways opening outwardly through another wall thereof, one of' said passageways communicating with said chamber adjacent one end thereof, said cylindrical member having a reduced diameter outer peripheral portion, the other of said pair of passage-ways communicating with said peripheral portion, a piston having a head portion. positioned within said cylindrical member and having a hollow stem portion extending outwardly of said end wall, an adapter, means securing Said adapter to said stem portion, a vsleeve telescopi-ng'over said cylindrical member, one end of said sleeve being secured to said adapter, the other end portion of said sleeve extending beyond said peripheral portion to form an outlet chamber and toward the other end portion of said cylindrical member whereby said sleeve is guided at spaced points for reciprocal movement longitudinally thereof, said cylindrical member having a passageway leading from said piston chamber adjacent said cylindrical member one end walland' opening into said outletV chamber, means surround-ing said` stem portion intermediate said last-named passageway and said cylindrical meinber one. end wall and co-operable with said cylindrical member to guide said stem portion, said stem portion having a passageway opening from the hollow interior thereof and positioned longitudinally of said stem portion so that at one position of said piston said stem portion passageway opens into said outlet chamber, the longitudinal position of said stem passageway being such that upon movement of said piston in one direction said stem portion passageway is closed by said surrounding means, and meansA for conducting rluid from the portion of `said piston chamber which is intermediate said head portion and said chamber one end to the hollow interior of Said stem portion.

2. In a pressure-operated ram mechanism, a platelike base having a platelike portion extending laterally thereof, said portion having an aperture opening through one face thereof, a cylindricai member having a portion held within said aperture, said cylindrical member having a piston chamber therein opening through one end wall thereof and having a pair of passageways opening outwardly through another wall thereof, one of said passageways communicating with said chamber adjacent one end thereof, said cylindrical member having a reduced diameter outer peripheral portion, the other of said pair of passageways communicating with said peripheral portion, a piston having a head portion positioned within said cylindrical member and having a hollow stem portion extending outwardly of said end wall, an adapter, means securing said adapter to said stem portion, a sleeve telescoping over said cylindrical member, one end of said Sleeve being-,secured to said adapter, the other end portion of said sleeve extending beyond said peripheral portion to form an outlet chamber and toward the other end portion of said cylindrical member whereby said sleeve is guided at spaced points for reciprocal movement longitudinally thereof, said cylindrical member having a passageway leading from said piston chamber adjacent said cylindrical member one end wall and opening into said outlet chamber, means sur` rounding said stem portion intermediate said last-named passageway and said cylindrical member one end wall and co-operable with said cylindrical member to guide said stem portion, said stem portion having a passageway opening from the hollow interior thereof and positioned longitudinally of said stem portion vso that at one position of said piston said stem portion passageway opens into said outlet chamber, the longitudinal position of said stem passageway being such that upon movement of said piston in one direction said stem portion passageway is closed by said surrounding means, means for conducting uid from the portion of said piston chamber which is intermediate said head portion and said chamber one end to the hollow interior of said stem portion, and means controlling fluid flow through said other of saidv pair of passageways.

3. In a pressure-operated ram mechanism, a plate-like base having a platelike portion extending laterallythereof, said portion having an aperture opening through one face thereof, a cylindrical member having a portion held within said aperture, said cylindrical member having a piston chamber therein opening through one end wall thereof and having a pair of passageways opening outwardly through another wall' thereof;

one of said passageways communicating with said chamber adjacent one end thereof, said cylindrical member having a reduced diameter outer peripheral portion, the other of said pair of passageways communicating with said peripheral portion, a piston having a yhead portion positioned within said cylindrical member and having a hollow stem portion extending outwardly of said end wall, an adapter, means securing said adapter to said stem portion, a sleeve telescoping over said cylindrical member, one end of said sleeve being secured in iiuid tight relationship to said adapter to form a pressure chamber, the other end portion of said sleeve extending beyond said peripheral portion to form an outlet chamber and toward the other end portion of said cylindrical member whereby said sleeve is guided at spaced points for reciprocal movement longitudinally thereof, said cylindrical member having a passageway leading from said piston chamber adjacent said cylindrical member one end wall and opening into said outlet chamber, means surrounding said stem portion intermediate said last-named passageway and said cylindrical member one end wall and co-operable with said cylindrical member to guide said stem portion, said stem portion having a passageway opening from the hollow interior thereof and positioned longitudinally of said stem portion so that at one position of said piston said stem portion passageway opens into said outlet chamber, the longitudinal position of said stem passageway being such that upon movement of said piston in one direction said stem portion passageway is closed by said surrounding means, and means for conducting fluid from the portion of said piston chamber which is intermediate said head portion and said chamber one end to the hollow interior of said stem portion, said stem portion having a uid flow passageway leading from its `hollow interior to said pressure chamber.

BURNELL O. BURRI'IT.

REFERENCES CITED The following references are of record in the le of this patent:

UNITED STATES PATENTS Number Name Date 1,294,266 Hogg Feb. 11, 1919 1,441,097 Laughlin Jan. 2, 1923 1,552,768 Smith Sept. 8, 1925 2,167,941 Ernst Aug. 1, 1939 2,402,848 Senn June 25, 1946

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