US2368900A - Compression testing jig - Google Patents

Description

Feb. 6, 1945. R. TEMPLIN COMRESSION TESTI-NG JIG 2 sheets-sheet 1 VFiled March 15, 1943 ..ao o lo no lNvENjroR E/CHD L. MPL/N ATTORNEY Feb. 6, 1945. R. L.. TEMPLIN coMPREssIoN TESTING JIG Filed March l5, 1943 2 Sheets-Sheet 2 INVENTOR g/c BY enga-"Maw .Lvl-roRNEYl Patented Feb. 6,` 1945 kCOMPRESSION TESTING JIG Richard L. Templin, New Kensington, Pa.

Application March 15,

5? Claims.

This invention relates generally to materials testing apparatus and more particularly to a device for compression testing of thin sheet metal specimens.

f In a compression device or jig of the general type disclosed herein a thin sheet metal specimen is placed between two `iaws having small diameter rollers to engage the side surfaces of the specimen to yprevent the same from buckling or flexing. These rollers have heretofore been supported in an uncertain manner as by heavy lgrease in order that the rollers would offer minimum resistance to the compressive deformation of the specimen and to allow the specimen to have its maximum deformation at its top end and its minimum deformation at its lower end. For instance, the upper end of the specimen moves for the full distance of whatever deformation takes place while the bottom edge of the specimen theoretically has no deformation and accordingly the extentof movement of the specimen `progressively increases from top to bottom. In addition to having the rollers accommodate themselves to this variable movement it is also desirable to support the rollers so that upon removal of a specimen the rollers remain ina predetermined supported relation to the jaws as a self-contained part thereoi in following the compressive deformation in the specimen Ebut without imposing any undesirable resistance or restraint on the specimen. A further object is to provide improved roller supports in a compression jig that will allow complete freedom of action of the rollers when the specimen undergoes deformation due to compressive loading, and yet will restore the rollers to a predetern mined normal position upon removal of the specimen.

Other objects and advantages will be more apparent to those skilled in the art from the following description of the accompanying drawings in which: l

Fig. 1 is a perspective of my improved device witha specimen disposed thereon;

Fig. 2 is a sectional view through the device showing the specimen being compressed between the usual opposed loading elements of a testing machine; i

Fig. 3 is a perspective of one supporting jaw 1943,A Serial No. 479,297

' sup-port a sheet metal rspecimen 'I.

tails of construction; v

Fig. 4 is-an enlarged view axially of a .roller showing the character of its pivotal ends and the support thereof in the flexible fingers which are shown in section; and Fig. 5 is an enlarged end view of a roller and its supporting fingers to show a preferable offset relationbetween the axes of the roller andthe holes in the ingers forl journalling the roller.

#This type of device broadly comprises a frame I having a vertical recess' ZeXtending forthe full height ofthe frame to receive a pair of vertically adjustable T-shaped jaws or supports 3 and 4. The bases of the T-jaws bear against the opposed walls of the recess while a pair of transverse strips -5 andi; extend across the open side of the recess to hold the members 3 and 4 in position. Disposed along opposed edges :of the two T-shaped members are a series ofsmall ro1lers,8 and 9 to It will be understood Athat the jaws and roller` structures on keach side are identical and hence the description of one will suiiice for both. ,The rollers have machined conical ends Illy (preferably about 60 total included angle) journalled in holes I0' in flat spring-like lingers II and I2. These lingers are formed preferably from a single continuous sheetiotmaterial, such as spring brass, having a vertically extending base portion I3 bent slightly outwardly as yat I4 and then forwardly. The ngersvII and I2 are then formed by cutting-or milling a seriesof slots I'5 in the extended portion of the sheet metal. The base portion I3 is clamped against sides yoi the T-stem by keeper plates I 6 and lscrews I'I. 'The jaw and. roller structure 3 and B may be adjusted to accommodate specimens of different thickness by screws I9. As shown in Fig. 5, the center b of the holes in the lingers are slightly closer to the face of the T-supports than the center of the roller. This offset relation together with a slight axially inward pressure of the flexible lingers against the conical ends of the rollers will thus hold the same against the face of the T-supportsat all times while still allowing freedom of movement. of the rollers during compressive deformation of the specimen.

In operation, the specimen 1 is placed between the rollers which are adjusted to provide an initial contact with the specimen, the jaws 3 and 4 and specimen then being placed in .a 'ush position on a lower table 20 of a testing machine while an upper loading head 2I engages the specimen at a sufficient distance above the jaws toV allow compression of the specimenwthout any lia-bility of bending over its upper end. As compressive deformation of the specimen takes place the rollfers 9 laterally stabilize the thin sheet specimen against possible flexure. The rollers not only bear a-gainst the end faces of the T-jaws which provide a firm lateral support for the specimen but also have a rolling action along the jaw faces in which case a very small rspace between the rollers will be sufcient to allowI the,A rollersv to roll along without rubbing against each other, the rollers at the top of the' jaw, of course, having maximum movement and accordingly the spacing;`

the axes of the individual. rollers, arekept muetually parallelk and' perpendicular to the longitudinal or vertical axis of the specimen. In ad-Y dition, the rollers are held- 'in the apparatus so` that the axes of anyA pair ofrollers, (Tone on each side ofl the specimen)` are in. thesame horizontal plane; that is,v each roller is. directly opposite'its complementary mate. As a result ofmy improved]arrangementfa specimen may be removedl from between the, rollersl and the rollers willy still remain in .their normal position ready to receive vanother specimen.v However', thev spring-like flexiblesupporting fingers for the rollersand the offset axes of the rollers and holes insure that the rollers can readily adapt themselves to any necessary relative movementreither solely about the roller pintl'es or along the faces of the T-jaws in which latter case the fingers automatically restore they rollers to their initial position when the specimen is removed. `The foregoing and other advantages are particularly desirable in an apparatus for eitherv commercial testing' or scientific investigation of physical members supported in said frame and having opposed faces spaced from each other, anti-frictionr rollers vpositioned adjacent each of said faces to support the sides of a specimen, and flexible means supported by said jaw members for rotatably supporting said rollers and for allowing the latter to follow deformations of the specimen.

2. A device for holding a thin sheet specimen for a compression test comprising, a frame, jaw

members supported insa-id frame andv having opposed faces, spaced from each other, anti-friction rollers disposed substantially at right angles to the direction of compression loading and posi- .tioned adjacent each of said faces to support a' relatively thin specimen, and parallel spring-like ngers supported by said jaws for individually rotatably supporting said rollers.

3.y device forA holding a thin sheet specimen for acompression test comprising, a frame, jaw members supported in said frame and |having opposed faces spacedf from each other, anti-.friction roliers disposed substantially at right angles to the direction of compression loading and posisupport Ohesides of a Specimen, and means ca!"- ried by said jaw members for urging said rollers into Contact at all times with said' jaw faces.

5. A device for holding a thin sheet specimen for a compression test comprising, a frame, jaw membersv supportedr in said frameand' having opposed faces spaced from eachother, anti-friction rollers'positioned adjacent each of' said faces to support the sides of aspecimen, said rollers hav-` ing conical ends, and' flexible means supported by said jaws and having bearing surfaces for rotatv ably supporting said conical endsat a point on theside thereof away from the jawy faces, said' flexibleV means being 'biased axially inwardlyy of said rollers whereby said' bearing surfaces in acting on the outer portion of the conical surfaces ofl the rollers urge the sa me into Contact with said jaw faces.

' RICHARD L. TEMPLIN.

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