US2335480A - Bending machine - Google Patents

Description

Nov. 30, 1943.

O. BERG STROM BENDING MACHINE Filed Jan. 13, 1943 2 Sheets-Sheet l Patented Nov. 30, 1943 UNITED STATES PATENT OFFICE BENDING MACHINE Oscar Bergstrom, Evanston, 111., assignor to Orville R. Owens, Oollegeville, Pa.

4 Claims.

This invention which relates generally to bending machines is concerned particularly with certain improvements by which to perform simultaneously two or more bends in a single board made of some such material as plywood, pressed board material, etc. Such a multiple bend is desired for certain products, e. g. reflectors for fluorescent lights.

The principal object of this invention is the provision of means adaptable to existing machines by which boards may be given multiple bends, all uniform but varying widely in contour according to the form used. For this purpose I have devised a forming die, attachable to the usual bending roll, and itself complete with heating elements, adapted to cooperate with a pair of female dies adjustable toward and from each other, all the operating parts being properly shaped and co-related to produce the desired.

bends. By my invention a machine is convertible from one which make a single bend to one which may produce a plurality of bends of various contours and spacing.

The forming means attachable to existing machines by which multiple bends may be performed is simple, sturdy and strong. It is also readily fitted in place or removed therefrom, as desired, and in operation may be relied upon to produce dependably bends which will be uniform and in which imperfections and injury to the board will be lacking. A suggestive embodiment of my invention will be hereinafter described in detail in conjunction with the accompanying drawings at each end of the machine, between which are extended a fixed male bending die in the form of a roll [5 and therebelow a table T vertically movable on the columns, the table mounting a pair of spaced female dies in the form of bending bars l6 each adjustable toward and from the other to vary the distance therebetween. The

table is centrally divided or slotted lengthwise to receive a pressure plate I! supported upon piston rods l8 each of which is upwardly extended from a cylinder mechanism I9. In like manner the table is supported upon piston rods 2|] each extended upwardly from a cylinder mechanism 2|. These several table operating cylinder mechanisms 2| may be pneumatically interconnected with a source of pressure which is thereby equalized and made subject to control by an air reducing valve (not shown). So that the vertical table movements may be positively equalized, I have suspended from the table near each end of the machine a post 22 whereon is a rack bar 23 (see Fig. 5) each in mesh with a gear 24 carried fast at opposite ends of a shaft 25 that is mounted to rotate within bearings 26. The cylinder mechanisms H! are also desirably interconnected. pneumatically with a source of pressure, and a common automatic valve control for the two sets of cylinder mechanisms I9 and 2| may also be: provided whereby to assure timed operation thereof, the pressure bar being raised first to clamp and hold the work W against the male die, the table thereafter being raised to bring the female dies into cooperative position so that the work is bent in consequence, and finally the table and also the pressure plate being lowered to release the work at the conclusion of the bending operation.

The female dies, i. e., the bending bars iii, are supported upon rails 30 which, together with the bars, may be shifted toward and from the longitudinal center of the machine whereby to vary the spacing therebetween. The connecting bolts 3| which are entered through transverse slots 32 in the table afford a convenient means of securing the bending bars in a desired position of adjustment. Also by substituting other rails of greater or lesser height the female dies may be brought closer to or further from the male die. The work W, such as a plywood sheet, a pressed board, etc., is placed across the two bending bars, preferably upon an underlying spring steel shield 33, then the rising pressure plate engages the shield from below to clamp the work against the male die, and iinally an upward movement of the table advances the bending bars against the shield which protests the work from frictional contact therewith while the work is bent upwardy in conformity with the contour of the male die. Where the machine is long and the male die is transversely small, there may be need of intermediate bracing such as is provided by the several struts 34 adjustably secured to blocks 35 at spaced intervals along the upper surface of this die, these struts being connected to a common head 36 which is supported at its ends upon columns 31 which extend upwardly from the housings II.

The initial position of the Work before start of the bending operation is indicated in Fig. 3, whereas in Fig. 4 I have shown the work and machine as at the conclusion of, this operation. To facilitate production of the desired bend in the work without injury thereto, the male die is provided interiorly with one or more electrical heating elements 38 in connection with a source of energy, this element (or elements) extending lengthwise of the die, the heat thus delivered being transmitted through to the exterior of'the die for delivery to the work in the to-be-bent area thereof.

The machine thus far described has capacity.

for producing a single bend in each operation. Multiple bends require that the, work be shifted and that the operation be repeated. Not also does this involve the time factor, but a correct positioning of the work for each operation, if the bends areto be accurately located relative to each other. With a View to adapting such a machine to the performance of. multiple bends in a single operation I have devised an attach,- ment for the male die, itself a male die different in form therefrom but supplementary thereto, and yet complete for cooperation with the spaced bending bars which constitute the female dies. As shown, this supplementary male die, which is of a contour suitable for producing double bends in a board which is to serve as a light reflector, consists of a forming shell, preferably of cast metal, in channel form with smooth exterior forming bottom and side faces 40 and 4| respectively, the latter terminating in inturned flanges 62 extending toward; each other but stopping at linear points about diametrically opposite the roll l5 with which they may engage. Interiorly the shell bottom is built up to provide a curved' seat 4'3 conforming toan extended areaof the bending roll along its under side with which it'is engaged. Between this seat and the two flanges are spaced chambers containing heating elements 44 affixed interiorly to the bottom and sides of the shell. By this arrangement heat from the element 38 within the bending roll may be transmitted therethrough to the central bottom of the shell whose outer bottom portions and sides: are heated directly by the elements 44.

A forming shell of this character may be sus pended from the roll and yet be maintained in fixed engagement therewith as by a plurality.- of saddles 45, each having. a reinforcing rib Miland out-turned feet 4'! through which bolts 48': may be extended for screw-threaded connection'with the shell flanges wherein are formed threaded sockets for reception of the bolt ends. At a-top point in each saddle is a boss 49 through which is a radial bore threaded to receive a screw 50 having a pointed acting end adapted to engage the bending roll upon its top side. By advancing each screw slightly the associated clamp may be adjusted as required for expansion of the bending roll when heated, this operation taking place before the bolts 43 are tightened to draw the shell closely against the under side of the same roll. Also, the ends of these bolts form very slight sockets in the top of the roll whereby they tend to remain fixed'in position thereupon. At the ends of the channel-like shell are placed closure plates 55 (see Fig. 5), amxed in position as by screws 56 which enter into threaded bosses (not shown) within the shell at the ends thereof, each plate being apertured to receive a fitting 51 through which pass electrical conductors 58 to connect with the heating elements 44. In this way the chambered spaces within the shell are closed off at the ends so as to retain therein the heat which emanates from the elements when energized.

In operation, work which is laid across a pair of spaced bending bars (with a spring shield intervening) will be doubly bent around the forming shell to assume substantially the permanent form which is shown in Fig. 4. While this operation proceeds, the entire to-be-bent area of the work issubjected to heat in a definite amount. This makes for a faster, more dependable and safer operation. In changing from a flat to curved or other form, the work is protected by the shield from friction with the female die, so that its surface is not scratched, marred, or marked.

I claim:

1'. In a bending machine, the combination of a hollow male die, a pair of Spaced female dies ad.- justable toward and from each other and spaced from the male die a distance sufficient for reception of a board therebetween, means for producing relative movement between the male and female dies to the extent that the latter may occupy positions alongopposite sides of the former to bend a board in conformity with the forming surface thereof, heating means extended longitudinallyof the male die centrally of the female dies, a forming shell ofchannel form applicable to the male die intermediatelyof the female dies and adapted to occupy a position therebetween, the shell being formed interiorly with a central seat'conformed to and engaging with the proximate surfaceof the male die and'with inturned flanges extended'close-to the male die at points remote from theseat and definingtherewithtwo side chambers open only toward the. male die, heating means: extended longitudinally. withinithe twoshell chambers, a, plural-ity'of; saddles laid over the male die and. extended towardfopposite edges of the shell, screw means connecting-each saddle and the-shell adaptedto-draw and hold the latter tightly against the former,- and ;screw means extended througheach. saddle at a point opposite the shell engageablewith the-male die withvariablefriction to hold the. saddle. in aa'fixed position of adjustment thereupon.v

2. In a bending machine, the combinationofa male die, a pair of spaced female dies adjustable toward andfrom each other and spaced-from the male die a distance sufiicient forreception of a board therebetween, meansv for producing relative movement between the-male. and female dies to the extent ,thatthe latter mayoccupypositions along opposite sides. of the former-t0 bend a board in conformity with the formingsurface thereof, a forming shell applicable to. the male, die intermediately of, thefemale dies-and adapted to occupy av position therebetween, the vshell being formed interiorlywith .a chamber. open only to.- Ward themale die, heatingrneans-extendedlongitudinally within the shell, chamber. a, plurality ofsaddles laidoverthe maledieand extended toward, opposite. edges of the. shell, andscrew means connectingeach saddle and. theshell adapted to draw and hold, the latter tightly against'the former.

3. Ina bendingmachine the combinationzofa male die, a pair of spaced female dies spaced from the male die a distance sufficient for reception of a board therebetween, means for producing relative movement between the male and female dies to the extent that the latter may occupy positions along opposite sides of the former to bend a board in conformity with the forming surface thereof, a forming shell applicable to the male die intermediately of the female dies and adapted to occupy a position therebetween, a plurality of saddles laid over the male die and extended toward opposite edges of the shell, and screw means connecting each saddle and the shell adapted to draw and hold the latter tightly against the former.

4. In a bending machine, the combination of a male die, a forming shell of contour other than the male die afiixed immovably thereto, a pair of spaced female dies adjustable toward and from each other and spaced from the shell a distance sufficient for reception of a board therebetween, means for producing relative movement between the male and female dies to the extent that the latter may occupy positions along opposite sides of the shell to bend a board in conformity with the forming surface thereof, means for heating spaced areas of the shell and other means independently thereof for heating the male die in an area between the spaced heated areas of the shell, and means extending between the shelland male die opposite the heated area of the latter for conducting heat to the shell in the unheated area thereof.

OSCAR BERGSTROM.

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