US3868102A

US3868102A - Contour-conforming clamping device

Info

Publication number: US3868102A
Application number: US444710A
Authority: US
Inventors: Maxwell Pevar
Original assignee: Individual
Current assignee: Individual
Priority date: 1972-04-27
Filing date: 1974-02-22
Publication date: 1975-02-25
Anticipated expiration: 1992-02-25

Abstract

This application discloses a clamping device for efficient application and distribution of clamping forces over engaged flat and contoured objects by utilization of multiple, movable engaging elements and thereby rendering more efficient use of the total applied force and avoiding harmful concentrated loads against objects being held. It includes adjacent gripping jaw members having closed-end bores in which tubular arbors supply pressure fluid, such as hydraulic liquid, from a common manifold and pressure reservoir for supplying member-distending fluid, together with means for controlling fluid flow and means providing for fluid supply from outside the internal fluid system.

Description

[111 3,868,102 1' Feb. 25,1975

2,663,339 12/1953 Verderber..;........,.................

[ CONTOUR-CONFORMING CLAMPING DEVICE [76] Inventor:

Primary ExaminerRoy Lake giggl 52 55 i i Assistant Examiner-Mark S. Bicks Feb. 22, 1974 Appl. No.1 444,710

57] ABSTRACT This applicationdiscloses a clamping device for effi- 22] Filed:

Related s Appncafion Data cient application and distribution of clampingforces [63] Continuation-impart of Ser. No. 237,111, April 27, Over engaged flat and contopred objects by utlhzauon I972 abandoned. of multiple, movable engaging elements and thereby rendering more efficient use of the total applied force 52 us. 269/26, 269/266, 269/267 9 avoiding 'Oads agailsl 51 Im. B23q 3/00 bemg h It adlacem, gripping [58] new 0 Search 269/24 26, 35, 266 267, members having closed-end bores in which tubular ar- 269/309 311 314 bors supply pressure fluid, such as hydraulic liquid, from a common manifold and pressure reservoir for [56] References Cited supplyirfig membfir-disttleniigg fluig, together g/ith' means or contro mg U1 ow an means provi mg UNITED STATES PATENTS for fluid supply from outside the internal fluid system. 1 499,989 7/l924 Lehmann.....................r. 269/266 X 2,399,824 5/l946 Pressman 269/266 X 10 Claims, 6 Drawing Figures 1 CONTOUR-CONFORMING CLAMPING DEVICE RELATED APPLICATION S This application is a continuation-impart of my pending application, Ser. No. 237,111, filed Apr. 27, 1972, now abandoned.

BACKGROUND AND SUMMARY OF INVENTION The present invention relates to contour-conforming clamping devices which apply distributed force, especially to devices for holding objects firmly to permit work to be done on them, and has for an object the provision of improvements in this art.

The devices disclosed herein may have a great variety of uses but one use which may be mentioned as particularly suited for the use of the present device is for holding parts for machine shop operations, such as drilling, milling and planing.

In recent years considerable effort has been placed on adapters and jigs to provide greater holding force on objects in bench vises, milling machine bed vises, magnetic chucks, etc. This effort is demonstrated by the large variety of adapters presently being marketed. The basic problem is that a contoured part when placed between the flat jaws of vises is contacted by point and line engagement. Therefore, when the vise is closed on the object greater loads than desirable are concentrated in these points, often marring the surface of parts and often brinelling them when the object is made of material softer than the jaws of the vises.

This need for better distribution of load is exemplified by the present use of metal powder-filled plastic molds cast to object contours wherein the mold when set up is placed between the object and the vise jaw and when the vise is closed the load is distributed through the plastic mold against the object. Also material such as low melting point castable metal alloys are used for mold material. The problem with these methods is that an individual mold must be cast for each different shaped part. Also, such mold materials often break and deform under load. They also require time and labor to prepare.

Devices for engaging object contours have been produced in recent years. One such device uses adjustable sliding wires for tracing a variety of'contours for lofting purposes. It does not apply holding force against the object. Another such device, shown in my U. S. Pat. No. 3,363,209, Contour Conformable Magnetic Adapter Device, Jan. 9, I968, uses sliding ferromagnetic laminates to transmit magnetic flux into contoured parts of ferromagnetic material more efficiently. Application of force is not easily achieved by this device and large forces would require extremely large electrical equipment. The device is not suitable for applying force to non-magnetic objects suchas aluminum and titanium.

None of the aforesaid devices have as objects those of the present patent disclosure which shall be demonstrated by the following objects of the present invention.

One of the particular objects of the invention is to provide adapter devices comprised of multiple jaw members activated by an internal hydraulic system thereby providing equal load to each engaging jaw member and distributing the holding force over the surface of the object.

Another object of the invention is'to utilize these adjustable hydraulic activated jaw members in the design of vises, grinding chucks, two and three axis table holding arrangements, and the like.

Another object of the invention is to utilize existing shop air and hydraulic lines directly into the housing and jaw arrangements to directly 'apply the force against the jaw members thereby forcing them against the object being held.

Another object of the invention is to utilize various hydraulic and accumulator arrangements in these devices with valving controls to allow for the rigidizing or maintaining of the set contour and thereby be able to place part after part of the same geometry within the jaws with least effort and maximum ease in positioning for similar operations.

Another object of the invention is to provide means wherein the stroke of the jaw members is of controlled distance and that the jaw members are restrained from being extended excessively to get out of operative position or be separated from the assembly.

The above and other objects of the invention, as well as various novel features and advantages, will be apparent from the following description of an exemplary embodiment, reference being made to the accompanying drawings, wherein:

DRAWINGS FIG. 1 is an isometric view of a pair of self-aligning jaw devices of the present invention adapted to a milling machine vise and applying a distributed holding force on a contoured part;

FIG. 2 is an isometric view of a cut-away section of a single self-aligning device with a view of arbors, jaw, and jaw retaining arrangement;

FIG. 3 is a cut-away section taken on line 33 of FIG. 2 with the jaw partially extended;

FIG. 4 is a view of three adjacent jaw members at zero, half and full stroke;

FIG. 5 is a cut-away view along line 55 of FIG. 2 of the manifold arbor and accumulator arrangement;

FIG. 6 is a sectional view of an arbor along line 6-6 of FIG. 3.

SPECIFIC DESCRIPTION As shown in FIG. 1, a workpiece 6 of varying geometry or contour is held for a machine shop operation on a milling machine bed 1, as by positioning the workpiece between a pair of self-aligning clamping devices 4 with selfaligning jaw members 5 engaging the workpiece along its contoured surface. The self-aligning clamping device 4 is positioned on the sliding vise 2 by bolts, set screws or the like. The sliding vise 2 is adjustably positioned to the machine bed I by bolts,'set screws or the like. The sliding vise uses fluid from an external hydraulic system fed by line 3, FIG. 1, to apply force against the face'of the vise.

A feature of the present invention is to utilize this pressure fluid applied force toactivate the self-aligning jaw members 5 by means of the hydraulic system.

Tubular arbors 9 are fitted into openings to a housing base 20 and these openings connect with a manifold chamber 11. Manifold chamber I1 is connected by a by-pass passage Ila controlled by a valve I7 to accumulator or reservoir chamber 13. The reservoir chamber I3 is shown as extending completely through the housing base 20 and having threaded end openings which are shownto be closed by removable plugs. 1 4

which may be removed and replaced by external pres; sure fluid line connections for filling the system'with fluid under pressure when desired. The arbor of this embodiment hasan O-ring seal 10 which engages in a bore 21 of the jaw member 5. The jaw member is slidt j r 3,868,102 f f hers, as by removing thecovers pulling the jaw,

able along the arbor, beingmoved outward by means of the hydraulic fluid applied through the end of the the jaw member. Retaining lips or projections 18 on the jaw. members 5 slide along'closed end grooves 190. in r the top and bottom lids or covers 19; V r it When adapting the present invention to standard bench viseswith limited opening'within the vise, theaccumulator feature,-shown herein,.becomes significant,

Full utilization ofthe jaw stroke is achieved by retracting all jaw members 5 by externally applied force with the accumulator bypass valve 17 openi The longstroke accumulator spring behind piston 16 with O-' ringseals lllai's thereby compressed. The jawmembers 5 remain infthe retractedjposition if the valve 17 is closed. A part to be held is placed in the vise and the valve 17-isopened.The accumulator spring 15 extends, forcingliquid out of the tubular arbors and moving the jaw membersS into engagement with the work. The ac curnulator, valvetl7 is then again closed. The vise Bis" then actuated, applying force against the work. The by? t p draulic system herein shown'distributes the force to all" jaw members thereby applying uniform force against the work.

' p it will beapparent that withinthe rangeof permissi is 'ble movement between the jaw membersS the ,jaw' members will fitanyarticle curvature, positive or nega-' tive; or partly. both,. and thereby the holding force.

against'the part will be distributed uniformlybetween t V fthe jaw mem bersI-Thel exte'rnalforce applied to the vise I V may be by'screw, as in conventional ,vises, or by air'and hydraulic pressureand other means apparent to those skilled in the mechanical arts. 7

lt'desired, an entire vise or work bench Imaybeoutfitted with self-aligning jaw clamping arrangements of the].

present invention. making the jaws integral with the construction'of such vises and blenchesand the like. 7

r The arrangement of FIG. 1 may be adaptedto grinding chucks, and may be constructed vertically to provide up or down force for deep drawing and hold-down operations. Another such utilization is to construct a.

flat table'with vertical sides wherein'the jaws protrude from the bottom and sides; thereby providing three-axis holding pr difficult tohold items.

' tant advantages over prior arrangements in which the, V jaw memberswere carried by the piston, members, of,

. tural'supportwithinthe jaw membenlt reducesthe' 7 bets.

marnbers offthe arbors and putting on other. jaw mem" Multiple valving members to allow'each jaw' member to be locked individually in position after adjustment "and prior to applying force against the .workbyclosin g the passages to the arbors by valves9a., V

(The arrangement of tubular arbors within the bores of the clamping jaw membershas a number of, imporcylinder-piston actuating devices. Itserveslas a struc:

axial space because the power-actuating device is disposed within the jaw member instead of being external V to it. It allows the inner ends of the jaw members to. be of non-round shape here rectangular; soas to" be I readily arrangedin guides to holdthe workpiece for close working, tolerances. And it allows the inner ends of the jaw members to fit closelyagainst each otherrand against retainingguidemeans and side retaining means, j V

here the end projections 20a of'the housing and the re- If desired, the arbor can be manufactured n-dmht n strength heat treated alloy steel higher bending moments on. the hardness of the work to be held. Toolsteel jaws are suitable for hard steel whereas mild steel andalurninumjaws' might be favored for holding alurninurri and inorder to sustain,

brass parts. Hard rubber and plastic jaws'might be more favoredtor hQlding glass and ceramic parts. The present arrangement provides ready exchange ofjaw mem j outfur-ther to provi otherjawfmembers I N a V I I 1 r 1 Howevenby providingian ample accumulator chant;

Another feature of the invention s toutihze replacet a able jaws which can be of various hardness depending taining cover plates 19,.ito1hold the workpiece more firmly for greater precision in maching operatiohs.

If the fluidis confinedin the manifoldcharnber ll,

. as by having the by-pass-valve l7 closed, the jaw mem hers Sica'n have some. adjustment by transferof fluid. between eachotherthrough the common manifold I chamber. However, for this tofbe permissible" the jaw membersrnust initially bein anfinterrnediateposition, preferably neartheir-'mid height' position,ibecause if. they are; all inathe innermost position, none can be moved downfurther relative 'to the others; and itlthey 1; are all in their'out'ermost position, none can be moved V despacefor fluidforced 'backby" bergby-pass orrnain controi valve,and separate jaw member yal'vegawide r'ange'of adaptationand control n and locking position can be achieved. The vise parts; r I gfix'ed and" movablefprovide for exerting any desired 7 force. on the jaw devices,jawgmembers and workpiece. after. the; jaw members" have" properly engaged the 1 workpiece.

, The internal accumulator reservoir chamber islhandy but itcanbe seenthat, withthejtnain supply valve l7? i theindividualljawflmembler ivalves9a ,he rebypro- V vided,the same. measureof control can be achieved by 'usingdirect connection to external pressure fluid lines instead of using the accumulatonas stated above, as by removing a plug 14 at the by-pass end and connecting .a pressure fluid line to the threadedopening'forrthe' I plug;

7 While one embodiment of the invention has been illustrated by way of example, it is to be understood that f there may be various embodiments and modifications within the general scope of the invention. lclaimzcanbe accomplished at the jaw.

1. A 'contour-conforming clamping device for,'apply- V ing-uniformlydistributedclamping engagement with 7 contouredobjects, said device comprising a housing base provided with aplurality of pressure fluidsupply passages, a'plurality 'of tubular arbors'affixed to the housingbase and having their interior tubular spaces 7 separately in fluidwconnection' with said supply pas V sages, a plurality ot closelyadjacent vise jaw members 7 i having outwardly-closed inwardly-open bores slidably receiving said tubular arbors interiorly thereof, said tubular arbors and the bores of said jaw members having sealing means therebetween, and openings in the arbors beyond said sealing means for supplying fluid within the bores of said vise jaw members in chambers of variable length between the ends of said arbors and the ends of said bores to urge the jaw members outward, and means for retaining said vise jaw members in sliding operative position on said tubular arbors.

2. A clamping device according to claim 1, wherein said base is provided with a common manifold chamber, the tubular spaces within all tubular arbors and their fluid passages communicate with said common manifold chamber, and which further includes a separately operated cut-off valve for each supply passage which admits fluid to or from said manifold chamber to extend the vise jaw member or allow its retraction when the valve is open and which locks fluid within the member bore when the valve is closed to hold the vise jaw member against yielding return movement.

3. A clamping device according to claim 1, wherein said base is provided with a common manifold chamber. the tubular spaces within all tubular arbors and their fluid passages communicating with said common 4. A clamping device according to claim 1, wherein a removable jaw-retaining side cover plate is provided for said vise jaw members, said side cover plate having means which cooperate with means on said vise jaw members for retaining said vise jaw members in sliding operative position on said tubular arbors.

5. A clamping device according to claim 4, wherein said retaining means for said vise jaw members comprises cooperating projections and closed-end grooves on said vise jaw members and side cover plate.

6. A clamping device according to claim 3, wherein each of said arbor passages is provided with a cut-off valve to allow passage of fluid when the valve is open and to lock fluid in the bore of a vise jaw member to hold the vise jaw member against yielding return movement when the valve is closed.

7. A clamping device as set forth in claim 3, which further includes means in said supply reservoir chamber for urging the flow of fluid from said supply reservoir chamber into said manifold chamber.

8. A clamping device as set forth in claim 6, which further includes means in said supply reservoir chamber for urging the flow of fluid from said supply reservoir chamber into said manifold chamber.

9. A clamping device as set forth in claim 7, in which said means for urging fluid from said supply reservoir chamber comprises a piston and resilient means urging said piston in the direction to force fluid from said supply reservoir chamber toward said by-pass passage and manifold chamber.

10. A clamping device as set forth in claim 4, wherein said sealing means comprises sealing rings carried by said arbors adjacent their outer ends.

Claims

1. A contour-conforming clamping device for applying uniformly distributed clamping engagement with contoured objects, said device comprising a housing base provided with a plurality of pressure fluid supply passages, a plurality of tubular arbors affixed to the housing base and having their interior tubular spaces separately in fluid connection with said supply passages, a plurality of closely adjacent vise jaw members having outwardly-closed inwardly-open bores slidably receiving said tubular arbors interiorly thereof, said tubular arbors and the bores of said jaw members having sealing means therebetween, and openings in the arbors beyond said sealing means for supplying fluid within the bores of said vise jaw members in chambers of variable length between the ends of said arbors and the ends of said bores to urge the jaw members outward, and means for retaining said vise jaw members in sliding operative position on said tubular arbors.

3. A clamping device according to claim 1, wherein said base is provided with a common manifold chamber, the tubular spaces within all tubular arbors and their fluid passages communicating with said common manifold chamber, a fluid supply reservoir chamber in said base, a by-pass passage between said fluid supply reservoir chamber and said manifold chamber, and a cut-off valve for said by-pass passage which admits the passage of fluid through said by-pass passage for extension or retraction of said vise jaw members when the by-pass valve is open and which locks fluid in said manifold chamber and bores to hold the vise jaw members against group retraction when the by-pass valve is closed.

4. A clamping device according to claim 1, wherein a removable jaw-retaining side cover plate is provided for said vise jaw members, said side cover plate having means which cooperate with means on said vise jaw members for retaining said vise jaw members in sliding operative position on said tubular arbors.