US2269655A - Apparatus for minimizing distortion of aluminum and similar sheets - Google Patents

Description

Jan. I3, 1942. Q FOUL-rz 2,269,655

APPARATUS FOR MINIMIZING DISTORTION 0F ALUMINUM AND SIMILAR SHEETS Filed May l0, 1940 2 Sheets-Sheet l Jan- 13, 1942- J. C. l.. FOUL-rz 2,269,655

APPARATUS FOR MINIMIZING DISTORTION OF ALUMINUM AND SIMILAR SHEETS Filed May l0, 1940 2 Sheets-Sheet 2 material.

Patented Jan. 13, 1942 UNITED STATES @AT- Ni" GFF ICE APPARATUS FOR MINIMIZING DSTORTEON F ALUlt/HNUM' AND SIMILAR SHEETS John C. L: Foultz, Tarentum, Pa.

Application May 10, 19405Serial No. h334,367

Claims. (Cl. 26S-2) This invention relates .to apparatus forl preventing distortion of aluminum sheets during vthe manufacturing Yprocedure employed in producing them.

In the manufacture of. commercial aluminum..

sheets it is considered necessary, or atleast highly desirable, to heat treat them by an immersion in va bath .of molten nitrate or similar YAfter the sheets have `been so immersed and consequently have -been heated to; substantially the temperature of the heat-treating liquid, they are withdrawn from ,the bath `and quenched, v'ordinarily by'being immersed in Lforces that all portions of eachsheetgaresubstantially uniformly stressed Whilef-thefsheet is 'in a condition to effectively -respond to `the stresses set up init.

In the drawings accompanying and lformingrv apart of thisfapplication,- Figurel 1; is al perspective View .of sheen-tensioning apparatuswhich may be employed for the purpose of subjecting .a plurality ofpsheets'totensional forces prior to, during and aftenthey-are immersedV in theheat-treating-liquid; Figure 2 is -a-fragmental sectional view of apparatus embodying. the features disclosed in-Figure 1, but includingfacilities for mounting and supporting-more-sheetsthan 2 is taken alonga line corresponding to the line II-II of Figure-1. Figure 3` is 'a fragmental side elevation of a sheet-clampingy device .which may constitute-a detailof the` apparatus illustrated:- inFigures 1 and 2; Figure 4 is a plan view of the device shown in Figure 3; and Figure 5 is a fragmental front elevation of the deviceshown in Figures 3 and 4.

tion convenient for 'immersion in=a Itreating-l liquid, such; for example, Ias molten.` sodium nitrate. 4v-As shown, 'theibeam' Il is in the form-of an I-beam,.which is provided with" crane :hooks or similar devices l2 located intermediate its ends and sovarranged'as to facilitatesuspending the beam while: it is retained in a horizontal position. The beam. ll is=adapted; to support two I* cages I3 which -are movable towardand away'from each other,v lengthwise of the beam, and are l adaptedl to berigidlyseCured inadjusted Apositions at points along the beam.

'Each cage Vmay consist of t a' box-like structure 4 open at its innerand outer sides and adapted -to receive a pluralityof sheet-clampingandtensioningrdevices 10.' AFor this purpose, eachcage i3 is shown as providedwithf cleats `Or-guides I4 which Vextend across the top zanclbottoml of the cage and which cooperatefwitheach other Y and with the-side walls l5-of the cage to provide a separate positioning compartment or `Way Vin are capable of being mounted and supported onf-.40

. the apparatus of Figure 1. The section ofi Figure The apparatus here illustrated includes a beam 5,0

4ll .whichis capable .of being suspended and which ris so n associated with auxiliary equipment .that it is capable of supporting anumber of sional -forces and While they are held in a. posirthe molten sodium nitrate.

whicheach sheet-clamping and tensioning Ydevice maybe mounted.

InI the apparatus illustratedyeach cage may lbe bolted to thelsupporting beam Hand Vin-Figure 1, I have illustrated thelbeam asprovided with two longitudinally extendingwbolt-receiving.

slots I6 .which are adaptedto cooperate-with i supporting straps I1, with `Which the cagesare spaced relation and` positioned so that .the .bot-

tom flange .and-the web of the I-.beamH .are

y located between them. .Bolt holes .are yformed in these Astraps so` as` to. cooperate with the, slots .I6` and bolts IB-extend throughthe .holes and the-slots. and are employed for the .purpose of rigidly' securing each cage in .position alongv the beam` Il.

It will be .understood vthat each cageis adapted to Ysupport one end -ofeach sheetwhile .the same is being subjectedfto the heat-treating eiect of It` should -also .be understood that the .sheets to be treated .-.are located-in parallel relation, both as to the beam ll and as to each other; that they span the space between the two cages and areso located that theirextended surfaces extend vertically. That is to say, the sheets are socarried-bythe support apparatus as to facilitate their movement intoand out of such treating liquidsas are .employed and 4so as to insure that each sheetwill rapidly respond tothe temperature of the-treating liquid without being materially affected by an adjacent sheet.

Each sheet is adapted to be engaged by two sheet-clamping and tensioning devices I which are applied to its opposite ends. In Figures 3, 4 and I have illustrated a form of such devices which may be employed with a support apparatus such as illustrated in Figures 1 and 2. As there shown, each sheet-clamping and tensioning device ||l consists of a box-like structure 20, which is open along one side, and a rotatable clamping element 2| which is located within and extends lengthwise of the housing.

Each element 2| is provided with a substantially cylindrical body portion and two cylindrical trunnions 22 which are eccentrically located with relation to the body portion and are journaled in cross supports 23. Each trunnion is shown as provided with apertures 22' for receiving adjusting bars, similar to capstan bars, for the purpose of turning the element 2| so that its cylindrical body portion moves to a sheetclamping position, with relation to one of the walls of the housing 20.' Each clamp and tensioning device |0 is adapted to be located in one of the positioning compartments formed by the transverse cleats I 4. A reference to Figures l and 2 discloses that each cage I3 is adapted to receive several of the devices I, and that each such device is located in an upright position so that the clamping surfaces thereof extend vertically.

In order to facilitate positioning the clamping devices Il] in the cages I3, each device is prolvided with caster rollers 24 located on the top and also the bottom thereof. In addition, each cage is provided with removable bars 25 which, when removed, give free access to the interior of the cage but, when in place on the cage, prevent the devices I0 from moving out of the cage. It should, however, be said that each device |0 is free to move along its positioning compartment or way, i. e., toward and away from its companion device ID located in the opposed cage I3, and is adapted to cooperate with its companion device in holding a sheet in placein the supporting apparatus. i

The operation of loading sheets to the supporting device so that it is properly positioned with relation thereto, involves securing one of the tensioning devices I0 to each end of each sheet. 'Ihis is accomplished by introducing the end of the sheet into the open side of the housing 2U and between the body portion of the cylindrical member 2| and the adjacent side wall of the boxlike structure. The cylindrical element 2| is then turned about its trunnions 22, so as to force it into engagement with the sheet and so as to clamp the sheet between it and the adjacent wall of the housing 2U. As shown in Figure 4, the trunnions 22 are so located with relation to the cylindrical body portion of the element 2| that the pull of the sheet clamped into position as above described, tends to increase the clamping action in that it tends to force the cylindrical surface into more intimate engagement with the sheet and also tends to press the sheet more rmly against the cooperating clamping surface of the housing 20.

In the apparatus illustrated, both the cages I3 are adjustable longitudinally of the supporting beam l I for the purpose of accommodating sheets of different lengths. Each clamping device I0 is movable, with relation to its supporting cage, for the purpose of facilitating the handling of the sheets but primarily for the purpose of subjecting the sheets to tension after they are mounted on the supporting apparatus. That is to say, each clamping device I0 is movably mounted in one of the cages I3 and is moved to different positions with relation to the cage during the operation of subjecting the sheet associated therewith to tensional strains.

While the clamping devices I0 of one cage I3 may be immovably mounted on that cage, and while the sheet-tensioning operation may be accomplished by the individual application of the active tensional force to but one of the two clamping devices secured to each sheet, I have shown means for simultaneously applying the tensional forces to all of the clamping devices ||l and under such conditions that all those devices are capable of moving, during the application of the tensional forces, in order to transmit tensional stresses to the associated sheets.

In the drawings, the beam I I is shown equipped with tension-applying means in the form of cables, pulleys and cable drums so arranged as to place each sheet under tension. A shaft 25 is journaled in bearings carried by housings 2l which are secured to a base 28 mounted on and secured to the top iiange of the beam I I. These bearing housings carry the crane hooks I2, heretofore mentioned, and they also provide a support for a shaft 29 which carries a pawl 30 adapted to engage a ratchet wheel 3| rigidly mounted on the shaft 26. The pawl 30 is yieldingly pressed against the ratchet by a fiat spring 32. The shaft 26 is provided with two cable drums 33-33', each of which is rigidly secured to it. Each drum is associated with two cables, one extending toward one end of the beam for the purpose of applying tension to the clamping1 devices I0 in one cage I3, and the other extending toward the other end of the beam for a similar purpose in connection with the tension devices housed within the other cage. As shown, cables 34 and 34 extend from the respective drums 33 and 33 to bars 35, each of which may be compared to a Whipple tree in that each transmits the pull of the tensioning mechanism to the sheets acted upon.

Figure 1 discloses three cables 36a, 36h and 36C, secured to each bar 35 and each cable is secured to one of the clamping devices I0. Each such cable (36a, 36h, 36o) is secured to its respective bar 35 by means of a coil spring 3l. Each cable is also provided with a length-adjusting device, shown in the form of a turnbuckle 38, for the purpose of independently adjusting the positioning of the associated clamping device I0 or for the purpose of individually controlling the application of the tensional force to that device and to the sheet to which it is clamped.

In Figure 1 of the drawings, I have diagrammatically illustrated the sheet-supporting apparatus as adapted to support but three sheets. This, however, is merely for convenience of illustration, since it is contemplated that each such apparatus will be so constructed that it will support a relatively large number of sheets. Each clamping device illustrated is in some way rigidly, and preferably permanently, secured to one of the cables 36a, 361) and 36o. As illustrated, this is accomplished by spreading the strands of the cable at the end thereof and welding the separate strands to the housing 20, of the particular clamping device I0 involved, so that the connection between the housing and cable is theforce-,and independently of theexpairglson.- .of

located at a Apoint substantially midway between the ends of thev housing.

n In orderI that the turning of the drums'33 may be employed-for the purposeof imposing tension onv the Vsheets .supported by, and bridgingl the space between the cages I3; I- have provided idler pulleys 4I and 42'.for guiding. the cablesa, 3.617 and 36e. The pulleys 4I .are-mounted on an idler shaft v3 andthe pulleys 42 are shown vmounted onan idler shaftlM. rBoth1the.shafts.43 andi -are journaledon afhousing 45 which isfsecured to the top iiange ofthe beam II.and, in eiect,

straddles the .adjacent cageI3. With such an arrangement, the turning of: the cable-drum shaft'26 tensions the cables `34,. 34- and in this way moves or tends to move'the clamping .devices I0, of the opposed cages I3, `away'from-each other and thus imposes tensionalstress-es of the desired magnitude upon.I each of the sheets carried bythe supporting apparatus.

In Figure 2, I have indicated that the supporting apparatus may beso constructed as toI carry at least six pairs of-clarnpingl devices I and consequently at least'six sheets to be heat treated. This viewy also discloses that each sheet will be associated with two tension-imposingcables so arranged as to impart the desired tension to it while it is secured in place in the supporting apparatus.

While there is a permissible variation in the` way the v'illustrated apparatusmay be employed, it will be understood that the apparatus is primarily designed-to not only support the sheets while they arersubmerged in the hot heat-treating'liquid, but also toso-support them that each sheet iscapable of being maintainedunder. tensionl with thetensionalstresses substantially uniformly distributed throughout the sheet, during the period it is subjected to the heat treatment.

A convenient procedure for accomplishing this '1f is to mount the sheets in place on the supporting apparatus and then manipulate the shaft 26 to impose the desired tensional strains on each sheet as a preliminary to introducing the sheets into the heat-treating liquid. In this way, the individual cables 35 can be adjusted as to length by means of the turnbuckles 38, and observation of the coil springs 3'I will give some indication as to the distribution of the tensional forces as among the various sheets, it being understood that it is desirable to so distribute th tensional stresses that all the sheets are strained substantially the same amount.

After tension is thus imposed on all of the sheets secured to the supporting apparatus, the apparatus is manipulated in such a way as to lower the sheets into a tank of the heat-treating liquid, i. e., into a tank of molten sodium nitrate or similar material. The proportions of the tank will be such as to completely submerge each sheet in the molten material and under conditions such as to insure a uniform distribution of heat throughout each sheet.

It will be apparent that the apparatus illustrated accommodates this procedure without causing the tension-imposing mechanism to contact the heat-treating liquid. That is to say, the shaft-,'26, the cable drums 33, the coil springs 31 and the turnbuckles 38 are `all above the heattreating liquid and are accessible throughout the entire heat-treating operation. With this arrangement, the springs 31 can effectively function to maintain a tensional strain on each sheet and independently of the yield of the sheet to thesheet in response.tothefheatrtrating .temperature. :With thisk vfin-z nind.; it will -be .apparenti that the; initial adjustment of g the mechanism, `in applying the 5 desired i. tensional l, force to each .of the various sheets, -will involveanappreciable extension of eachspring 3Ilso that it will be;- capable of maintaining .a ysubstantially constant .tensional stress in; the associated sheet throughout. the entire heat-treating operation.

AFor this reason,'I lprefer to employ. apparatus suclnas illustrated; ingFigure 1, i. e.,apparatus wherein all clamping devices I0 are -movably mounted 'in their respective supporting cages I3 and are ,movable .in response tothe .operation of applying tension to the sheets. "I also prefer the arrangement of apparatus illustrated wherein each cable (36a,` 36h, 36o) is'V provided with-a length-adjusting device 38 and a coil spring'31 since this `arrangement `divides the tensional v stresses .between two. springs. and thus .makes lit possible `to '.morenearly maintain .a substantially equal stress on each sheet `and independently of the;degree of yield and the amount ofexpansion encountered Vin each sheet whileit is being. raised to the. .temperature of the heat-treatingliquid.

The apparatus illustratedtalso makesitl possible rto maintain eachsheet under substantially the same .tensional stress throughout the yquenching operation. It vwill bei understood-that the sheets will'preferably be retained in place on rthe supporting apparatusy and under tension while beingv removedA from the heat-treating liquid and ywhile .being Aimmersed in and-removedfrom the quenching -liquid. It will; therefore, .beapparent that 'the apparatusy accommodates bothl the `heating and the cooling of the sheetsand underconditionsA such that each `sheet .is-subjected' to substantially the same .tensional strain-.throughout both operations.

I have not attempted to do more than define the characterizing features of my invention, in-l sofar as it involves the apparatus here illustrated. For this reason, I desire to have it understood that I have not attempted to design specific structural details such, for example, as the clamping devices and the mechanism in such a way as to most eiectively conserve space.

I, however, do wish it to be understood that in the preferred embodiment of my invention, all parts of the apparatus are to be fabricated from material which will effectively withstand the variations in temperature to which the apparatus is necessarily subjected and that the tensionapplying mechanism must be such that the tensional stresses in each sheet can be separately controlled and can beso applied as to impose a substantially uniform strain throughout all portions of the sheet. In addition, the tension should preferably be applied under conditions such as to maintain the sheet under tensional stress throughout the entire heat-treating and quenching operation.

It will also be apparent that Various changes may be made in the structural details of the apparatus herein described and illustrated without departing from the spirit and scope of my invention as dened by the appended claims.

Having thus described my invention, what I claim is:

l. A sheet-supporting apparatus for use in sheet-tensioning operations, comprising a sup-V port member, two cages mounted in spaced relation on said member, means for adjusting the position of one such cage along said member, a

plurality of sheet-*clamping devices supported by each such cage with the devices of one cage movably supported thereby and tension-imparting means carried by said support member for simultaneously moving all said movable devices to impart tension to the sheets engaged thereby.

2. Sheet-tensioning and supporting apparatus for use in sheet-tempering operations, comprising a support member, cages mounted thereon in spaced relationship, means for supporting a plurality of sheets between said cages comprising a plurality of sheet-clamping devices carried by said cages With some of said devices movable with relation to the carrying cage, means carried by said support member for simultaneously imparting movement to such movable devices to tension the sheets engaged thereby, and separate means for independently positioning each such movable device.

3. A sheettensioning and supporting apparatus for use in sheet-tempering operations, comprising a substantially horizontally extending support member, cages depending from said member in spaced relationship, means compris ing a plurality of separate sheet-clamping devices carried by each of said cages for engaging sheets to be tempered and for supporting a plurality of such sheets in parallel, spaced relation between said cages, adjustable means carried by said support member for simultaneously actuating at least some such clamping devices to impart tension to the sheets engaged thereby and separate mechanisms forming a part of said tension imparting means for substantially maintaining the tension-imparting forces exerted by such clamping devices independently of the expansion of the sheets engaged thereby.

4. In a sheet-supporting apparatus for use in sheet-tempering operations, a substantially horizontally extending support member, means for supporting a plurality of sheets in parallel spaced relation below said member and in substantially parallel relationship to said member, comprising two cages depending from said member and located in spaced relationship thereon, a plurality of vertically extending sheet-clamping devices carried by each such cage and located in parallel relationship thereonl means carried by said support member for simultaneously moving at least some of said clamping devices to impart tension to the sheets engaged thereby, separate means for independently positioning at least some of said clamping devices and separate means for substantially maintaining the tensionimparting force exerted by at least some of said clamping devices independently of the expansion of sheets engaged thereby.

5. In a sheet-supporting apparatus for use in sheet-tempering operations, a support member, means for supporting a plurality of sheets in parallel spaced relationship below said member and with the faces of said sheets extending substantially vertically, comprising two cages depending from said support member and located in spaced relationship therealong, a plurality of sheetclamping devices carried by each such cage with some such devices movable with relation to the carrying edge, adjustable tension-imparting means carried by said support member above said cages for simultaneously moving said movable clamping devices to impart tension to sheets engaged thereby, and separate means for substantially maintaining the tension-imparting force exerted by at least some of said clamping devices independently of the expansion of the sheets engaged thereby.

JOHN C. L. FOULIZ.

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