US2203027A

US2203027A - Bending table

Info

Publication number: US2203027A
Application number: US200597A
Authority: US
Inventors: Rudolph F Onsrud
Original assignee: ONSRUD MACHINE WORKS Inc
Current assignee: ONSRUD MACHINE WORKS Inc
Priority date: 1938-04-07
Filing date: 1938-04-07
Publication date: 1940-06-04
Anticipated expiration: 1957-06-04

Description

R. F. ONSRUD June 4, 1940.

BENDING TABLE Filed April '7, 193a 5 SheetsSheet 1 206%, DOUGLAS EOMSIPZ/D v June 4, 1940. I R. F. ONSRUD 2,203,027

, SENDING TABLE Filed April 7, 1938 5 Sheets-Sheet 2 6 7 9 6 7 Q r K 9 I f 1/ 4 /3 r5 z 2; 2/ Z2 78 I6 Z0 22 21 f7 79 Z4 a z: 6 2/ 9 m E f5 I? z I 20 4 /7 9 Z4 Z3 22 5 ZZ fl67ZZ/ 0 0062 06f. U/VJPUD June 4, 1940. QNSRUD 2,203,027

BENDING TABLE Filed April 7, 1938 5 Sheets-Sheet 3 .June' 4, 1940. R. F. ONSRUD BENDING TABLE Filed April 7, i938 5 Sheets-Sheet 4 001/6246 OMS/BUD June 4, 1940. F. ONSRUD I 2,203,027 SENDING TABLE Filed April 7, 1938 s Shee tS -Sheet 5 Patented June 4, 1940 PATENT OFFICE BENDING TABLE Rudolph F. Onsrud, Chicago,

Onsrud Machine Works, Inc.,

corporation of Illinois 111., assignor to Chicago, 111., a

"Application April 7, 1938. Serial No. 200,597

Claims.

The construction herein disclosed is designed for furniture manufacturers for use in making round corners. The machine is useful in bending sheet material, veneered stock, boards, laminated stock, pressed wood and similar fibrous substances responsive to the application of heat and mechanical force for forming round corners. Relatively thick material is grooved out on the inside of the ultimate curve prior to bending for the purpose of rendering the operation rapid and easy.

The objects of the invention are to provide a bending machine of the class mentioned with improved mechanical means for rapidly performing the bending operation with convenience and suitable for operating upon stock varying as to overall dimensions and thickness, and to provide improved means for forcing a bend of definite radius and for maintaining the fibrous material under compression and subject to the necessary temperature for rapidly setting the bent material in its new form. I The objects of the invention are accomplished by means of a construction as illustrated in'the drawings, wherein:

Figure 1 is a fragmentary perspective view of the front side of the machine.

Fig. 2 is a perspective view of the rearside of the machine.

Fig. 3 is an edge view as bent by the machine.

Fig. 4 is a fragmentary longitudinal section through the bending and heating elements of the table.

Fig; 5 is a section similar to that shown in Fig. 4 except that the hinged portion of the table is in changed relation to the fixed portion thereof with the stock partly bent.

Fig. 6' is a view similar to Fig. 4, but with the parts in 'that relation when the stock is fully bent.

Fig. '7 is a sectional detail taken on the line 1--1 of Fig. 4.

Fig. 8' is a fragmentary endview of 'the table for illustrating a modification thereof employing pneumatic means for operating the hinged portion ofthe table.

Fig. 9 is a fragmentary end View repeating part of the mechanism shown in Fig. 8, but showing the hinged portion of the table swung up with the stock therein bent at right angles.

Fig. 10 is a central longitudinal section of the construction shown in Figs. 8 and 9.

Square cornered furniture is frequently objectionable on account of possible injury: thereof a sample of stock from. Round cornered furniture is often favored on account of being less hazardous and because of its appearance. When the furniture is fabricated from fibrous sheet material it is desirable to equip the factory with facilities for accurately forming bends rapidly and in a manner to remain permanently in that form without stresses due to improperly set material. The present bending table is designed for that purpose and is arranged so that the bends may be 10 formed by manual operation of the machine in the case of. light materials or by power-operated means at the option of the user.

The construction illustrated consists of a table I having two sets of normally horizontal heavy i5 guide railsZ and 3. The guide rails .2 and 3 are in alignment, and each is slotted longitudinally at 4 to receive clamping bolts 5 which carry end guides or grips 6 for receiving therebetween the stock which is to be bent by the table. ple of material operated upon is indicated at 1. Exceptionally heavy stock is prepared, prior to operation thereon by the bending table, by grooving the board as indicated at 8 and the groove A samsometimes extends down to or near'the veneer 9.

Another preparatory step to bending is the application of a cement or glue to the surfaces of groove 8 and further the slipping into the groove of a flexible reinforcing strip I!) for backing up the veneer. This strip is also coated with an advhesive.

The rails 2 and 3 are connected together at their inner spaced ends bya bendable metal plate H such as spring bronze. The bent ends of plate II are clamped to the rails by means of metal facings and tie elements [2 for the rails. Tie elements l2 extend transversely of the rails to connect and hold them in definite spaced relation. The rails 2 are fixed on the table while the rails 3 hinge to swing upwardly therefrom.. 40

The plate ll serves both as hinge and as pressure transmitting and bend-formingelement, or separate provision is made for the hinge as explained for the modification shown by Figs. 8

and 9. Beneath the plate H is a pressure applying and heat transmitting block l3. This block is preferably of an aluminum composition for rapid heat conductivity and carries an electrical heating element l4 imbedded in the lower surface thereof. is concave,.as indicated at l5, according to the desired curvature of bend in material operated upon. The block is also mounted for limited selfadjustment to accommodate the bend radially by the spring mounting it on supporting cast- .55

The upper surface of the block ings H, which may be in the form of arms tied together by rods I8, I 9 and 2B.

The rods I8 and 20 pass through eye bolts 2| which are slidable in bearings 22 secured to the metal cross-members l2. Longitudinal motion of the eye bolts is resisted by springs 23 located between the bearings 22 and nuts 24 on the ends of the bolt. By means of this mounting of forming blocks l3, a limited lateral movement of the blocks is provided for, so that the latter may accommodate the bend in the material operated upon in that direction, but when the hinged part 3 is rocked upwardly, the block 13 is forced into firm contact with the bending plate H.

An opposite pressure is applied to the material operated upon by the inward reactance thrust of the clamping member 6 against the edges of the stock operated upon. The cement used is resinous or of a similar nature, so that it will set and harden rapidly on the application of heat and pressure. The heat which is applied through block l3 has the additional function of softening the substance of the material being bent and the bend is made easier because of the application of heat. If the fibrous material contains moisture, the moisture will be converted into steam and aid in loosening up the fibers of the material, so that they may be reset in the new formation upon cooling and are not under particular strain because of the bending operation. This is apparent from stock bent to round corners by this bending table, as there is no tendency for the corner to bend back toward its original flat condition, nor is there a tendency for a fracture or openings occurring in the curved surface. The finished corner may be machined, fluted, routed, or carved.

During the bending operation the outer curved surface of the bent material is supported by the metal plate I I which, toward the completion of the bend, is backed up by pressure received through block l3. Plate H, therefore, serves to prevent fracture of the material operated upon during the bending process. The application of heat for the proper resetting of the fibers of the board to the curvature of the bend requires from forty-five seconds to a minute and onehalf application through forming block or caul l3. It is unnecessary to glue a retaining veneer on the inside of the bend, also there is no requirement for close accuracy of the surface'of the inside out or groove 8. When particularly heavy stock is operated upon and there is necessity for more speedy penetration of heat to the bent material, an additional heater 25, Fig. 6, is applied to the inside of the'bend.

In case of bending veneered boards, it is advisable to have the core stock grain run parallel with the bend, and then it is unnecessary to make as deep a routed-out cut at the back of a panel as in cases where the core stock is run across the bend. With the grain of the wood running across the bend, it is preferable to rout out the back of the panel practically to the glue line between the core and the veneer or cross-band. Where the face veneer must run across the corner, it is preferable to run the cross-band at forty-five degrees to the grain of the core which may be then parallel with the corner. The thickness of the portion of the board which forms the bent corner depends upon the radius of the bend. In bending a thin plywood panel upon to one-half inch thickness or heavier panels where a corner post is not necessary, the thickness possible with a one inch radius is from one-eighth to threesixteenths of an inch; a two inch radius, onequarter inch thickness; a three inch radius, three-eighths to one-half inch in thickness.

The machine is useful with a wide range of' or casein glues or the conventional animal or vegetable glues and no means provided for clamping or removing the material in bent form, it is necessary to allow the material to remain in the machine from one to several minutes.

The hinged portion of the table is lifted by hand when lightweight material is operated upon, and is retained at the required angle to the remaining portion ofthe table by the hooks 26, Fig. l, drawn tight by eccentric latch elements 21.

Figs. 8 and 9 illustrate a modification wherein. a pneumatically-operated plunger 30 in a cylinder 3! is employed for forceably swinging the hinged portion of the table. In these views the hinged portion is indicated by numeral 32, and the stationary part of the table by numeral 33. The two parts of the table are hinged together by a flexible bend-forming plate 42 which is the same as the bend-forming plate ll of Figures 1, 2, 4 and 5 and serves the same function. The two parts of the table are also connected together in hinged relation by the support for the pressure-applying and heating block 4!. (See Figs. 4 and 5 where the block is numbered l3.) Motion is transmitted to the hinged part of the table from plunger 30 through the linkage 34. The fixed part 33 of the table carries brackets 35 to which are hinged at 36 brackets 31 slidably engaging portion 32 of the table. Bracket 35 carries adjustable stops 38 for engagement with pads 39 on brackets 31. The stock operated upon is indicated in Figs. 8 and 9 as a board 40. The pressure applying and heating block 4| is mounted similarly to block l3 shown in Figs. 4 and 5, and its function is the same; that is, providing a concave support of definite radius for receiving the bent corner and holding it to form while it becomes set in that condition through the'application of heat and pressure.

In the operation of the bending table the heating element is controlledas to temperature and period of application ofheat. Such control means, however, is not detailed in the drawings, as the invention relates to the construction of the bending table. Inperforming the'bending operation, the stock operated upon is placed between the cleats 6 when the hinged'part 3 of'the table is horizontal in alignment with the stationary part 2, as shown'in Fig. 4. The hinged part 3 is then lifted to swing around or to whatever angle of bend is required. The plate ll connecting the parts 2 and 3 forms the hinge and flexes to a curvature of a predetermined radius corresponding to the concave surface of heating block l3. The material operated upon presses down against the plate as the bend is being formed. The cleats 6 form end abutments for the board operated upon and force the bending area thereof against plate II.. The heating caul or block l3 applies opposite pressure to plate II with full contact along the concave surface of the block when the bend is fully formed. The block supports l1 hinge on the tie rods l8 and 20 and the eye bolt supports 2| for the tie rods may shift in their bearings against the spring 23 as these bearings move apart upon swinging motion of the moving part of the table with reference to the stationary part.

This spring mounting of the supports for the block, together with the springs l6 which permit a limited motion of the block around tie rod l9, provide for any needed self-adjustment of the block to the bend in the material operated upon. When using a machine such as illustrated in Figs. 1 and 2,.the hinged part of the table is held at the required angle with the stationary part of the table, during application of heat and pressure to permanently set the material in bent form, by means of hooks 26 and eccentric latches 21. In the form of machine illustrated by Figs. 8 and 9, thehinged part 32 of the table is held in its moved position the required length of time by the hydraulic or pneumatic operating means shown in these figures.

The forming operation provides an economical way of making a permanent corner construction for furniture. The joint is strong without reinforcements and while these are used for extra strength, nothing need be glued on the inside of the bend, as it will hold its shape. The application of heat and pressure allows the material to re-set in its new form free of stress. Ordinary ungrooved three-ply material of a thickness commonly required in furniture is readily bent without injury due to the protection aiforded by the forming element I3.

I claim:

l. A bending table of the class described, provided with a two-part support for fiat material, one part of which support is free to hinge relatively to the other part of the support, a hinge connection between the two parts of the support consisting of a flexible metal plate, a'heat and pressure applying block having a concave surface for engaging said plate, and a mounting for said block extending between the stationary and hinged portions of the bending table arranged to press the block against the plate according to the angular position of the hinged portion of the support with reference to the stationary portion of the support.

2. A bending table of the class described, provided with a two-part support for flat material,

one part of which support is free to hinge relatively to the other part of the support, a hinge 50 connection between the two parts of the support consisting of a flexible metal plate, a heat and pressure applying block having a concave surface for engaging said plate, and a resilient mounting for said block extending between the stationary and hinged portions of the bending table arranged to press the block against the plate according to the angular position of the hinged portion of the support with reference to the stationary portion of the support.

3. A bending table of the class described, provided with a two-part support for flat material, one part of which support is free to hinge relatively to the other part of the support, a hinge connection between the two parts of the support consisting of a flexible metal plate, a heat and pressure applying block having a' concave surface for engaging said plate, and a resilient slid- I able mounting for self-adjustment of said block extending between the stationary and hinged portions of the bending table arranged to press the block against the plate according to the angular position of the hinged portion of the support with reference to the stationary portion of the support.

4. A bending table of the class described, comprising a pair of angularly adjustable worksupporting elements for the material operated upon, a pivot hinge connection for said elements, power-operated means for effecting angular motion between said supporting elements, a flexible metallic plate forming an additional hinge connection between said supporting elements and forming therebetween a continuation of the support, a pressure and heating block resiliently and slidably supported on said hinged elements and having a curved surface for engagement with the flexible plate upon relative angular motion between the supporting elements.

5. A bending table of the class described, provided with a two-part support for material operated upon, one part of which support is free to hinge relatively to the other part of the support, a hinge connection between the two parts of the support consisting of a flexible metal plate, a pressure block, and a resilient mounting for said block extending between the two parts of the support arranged to press the block toward the plate according to the angular relation between the two parts of the support.

RUDOLPH F. ONSRUD.

CERTIFTCATE OFTCYIYRECTION.

Patent No."2,205,027. June L 1911.0.

RUDOLPH F. ONSRUD.

It is hereby certified that error appears in, the above numbered patent requiring correction as follows: In the drawings, Sheets 1 to )4 inclusive, signature of inventor, for "Douglas P. Onsrud" read -RudolphF. Onsrud-; and that the said Letters Patent should be read with this correction therein that the same'may conform to the record of the case in the Patent Office.

Signed and sealed this 6th day of August, A. D. l9LLO.

Henry Van Arsdale, (Seal) Acting Commissioner of Patents;