US2784761A - Bending machines - Google Patents

Description

Maich 12, 1957 R. M. sHAw, JR

BENDING MACHINES 5 Sheets-Swat 1 Filed May 26, 1955 INVENTORI.

kn! kAJ/Famizi; BY 52m ATTORNEYS.

March 12, 1957 R. M. SHAW, JR

BENDING MACHINE 5 Sheets-Sheet 2 Filed May 26, 1955 *N wamn 5% March 12, 1957 RM. SHAW, JR

BENDING MACHINES Filed May 26. 1955 5 Shetg-Sheet s' A TTORNEY S.

March 12, 1957 'R. M. SHAW, JR

BENDING MACHINES 5 Sheets-Sheet 4 Fil egi May 26 1955 amJ/a, a? 21 ATTORNEYS.

March 12,, 195 R. M. SHAW, JR WM BENDING MAgHINES- Filed May 26, 1.955 I 5 Sheets-Sheet 5 Fjgi United States Patent BENDING MACHINES Ralph Shaw, Jr., Edgewater Park, N. J., assignor to Pedrick Tool and Machine Co., Philadelphia, Pa., a corporation of Pennsylvania Application May 26, 1955, Serial No. 511,33tl

7 Claims. (Cl. 153-40) This invention relates to bending machines. More specifically, it is concerned with machines for operation upon work pieces such as bars, rods or tubing to shape them as may be required, for example, in the production of parts for chairs or other articles of furniture.

My invention has for its chief aim, the provision of a bending machine suitable for the above purpose which is simple in construction and reliable in operation; and which, except for manual placement of the work pieces therein and starting, is entirely automatic in effecting the bending in a minimum of time.

Other objects and attendant advantages will appear from the following detailed description of the attached drawings, wherein:

Fig. l is a view in top plan of a bending machine conveniently embodying my invention in one form.

Fig. 2 shows the front elevation of the machine with a portion broken out and in section.

Figs. 3 and 4 are views corresponding to Fig. 1 showing successive stages in the operation of the machine.

Fig. 5 shows the top plan of a modified form of my invention.

Fig. 6 is a fragmentary view showing another alternative embodiment of one of the elements of the machine.

Fig. 7 is a fragmentary view in section taken as indicated by the angled arrows VII-VII in Fig. 6; and

Fig. 8 shows an interchangeable member for use in the modification of Fig. 6.

With more detailed reference first to Figs. 1-4 of these illustrations, my improved bending machine as therein exemplified, comprises a pedestal-like base 1 which supports, at table height, a circular bed 2. Disposed within the hollow of the base 1 is a reversible elec tric motor 3 with an incorporated speed reducer 4 whereof the output shaft 5 extends up through the bed 2 and carries a small spur pinion 6 at its upper end. A spur gear 7 recessed into the bed 2 and meshing with the pinion 6, is secured to a vertical tubular shaft 8 which is rotative in a central bearing boss 9 of the bed. Fixedly mounted upon the wheel 7 in concentric relation thereto, is a larger spur wheel it) which, through an idler pinion 11, is arranged to drive a similar coplanar spur wheel 12. The pinion 11 and the spur wheel 12 are free 1y rotative respectively about upstanding studs 13 and 14 which are suitably anchored in a stationary bracket arm 15 extending laterally from and rigidly secured to the bed 2. As shown, a bracing bar 16 connects the upper ends respectively of the shaft 8 and the stud 14.

To the top of the spur wheel is bolted in eccentric relation to the axis of the latter, a segmental profile die element D in the form of a block whereof the outer or profile edge is curved as at 18 concentrically with the axis of said wheel, and whereof the ends are rounded off more or less abruptly on a very short radius. The profile edge 18 of the die element D is formed with a groove 19 which is semicircular in cross section in this instance for conformity with the cross sectional rounding of tubes or rods, such as the one designated T, to be bent in the W 2,784,761 Patented Mar. 12, M957 machine. Fixedly mounted side by side on the spur wheel 10 diametrically opposite the die block D are a self-latching hook-ended gravity dog 20, and a work holder 21. The work holder 21 is of a suitable pneumatically-actuated type and has grippers 22 between which one end of the tube or rod T is clampingly engaged in preparation for the bending. Compressed air is conducted to the work holder 21 from; a suitable source of supply (not shown) by way ofa pipe 23, which extends down through the hollow of the shaft 8, under control of a valve 24 (Fig. 2).

Cooperative with the die element D in the bending is a swaging element S which carries a series of swaging rollers 25 which are circumferentially grooved in correspondence with the grooving of said die element. The rollers 25 are freely rotative' about pins 26 which extend between and have their opposite ends anchored in a pair of disk components 27 and 28 of the swaging element S, which latter is secured to the top of the supporting spur wheel 12 by a plurality of bolts 29, said disks being spaced by collars 30 surrounding said bolts. A larger spacing collar 31, free to rotate about the stud 14, aids in maintaining the disks 27 and 28 of the element S in the desired spaced relation. It will be noted. from Fig. 1 that the axes of the rollers 25 are equally spaced in a compound curve of which the mid portion is of a radius R having its center in the axis of the stud 14, and of which the outwardly flaring flanking portions are of larger but equal radii R struck from centers x eccentric to said stud axis and are symmetrical relative to said mid portion. it is to be further observed that the extent or length of the mid portion of the compound curve is equal to that of the large profile edge portion of the die element D on the spur wheel 10.

A lug 33 secured at the periphery of the spur wheel 10 is adapted to actuate positionally adjustable limit switches 34 and 35 which are interposed in circuit with the drive motor 3 for a purpose presently explained.

Operation With the die element D and the swaging element S relatively positioned as in Fig. 1, one end of the tube or rod T to be bent is clamped in the holder 21 with its mid portion tangent to the profile edge of said die element. The motor 3 is thereupon started to rotate the spur wheel 10 clockwise, a spur wheel 12 being driven in the same direction through the idler pinion 11. The leading roller 25 carried by the swaging element S in the direction of rotation of the wheel 12 meets with the leading end of the die element D in the direction of rotation of the wheel 10. As the action proceeds, the work piece T is progressively bent about the outer edge of the die element D, by the following rollers 25 of the swaging element S through the position of Fig. 3 to the final position of Fig. 4 when the motor 3 is automatically stopped by engagement of the lug 33 with the switch 34-, the gravity dog 20 having in the meantime automatically hooked over the distal end of the work piece as is also shown in Fig. 4.

Due tothe described shaping of the profile edge 13 of the die element D and the described disposal of the rollers 25 on the swaging element S, the work piece T is bent to the configuration of a U with straight legs L and L and with the portion connecting the legs curved to the shape of the said die element. The extent of rotation imparted to the wheels 10 and 12 is such that in this instance, the leg L is flexed some what beyond parallel relation to the leg L before it is engaged by the dog 20. With the work piece now bent and its leg L restrained by the dog 20, the motor 3 is started in reverse with consequent rotation of the spur wheels 10 and 12 counterwise to the direction in which they turned during the bending, the motor being automaticaliy stopped upon I in Fig. 1.

' necting the legs.

3 opening of the limit switch 35 by the lug 33, and the die element D and the swaging element S being restored to the normal relative positions in which they are shown The dog 20 is thereupon manually retracted to release the leg L and the work holder 21 actuated to free the leg L for withdrawal of the completed work piece from the machine. Due to flexing of the leg L of the Work piece to the extent shown in the final stage of the bending as above explained, said leg automatically springs back into parallel relation to the leg L upon being released from the dog 20. By adjusting the switches about the wheel 10, the extent of rotation can be either increased or decreased if other than parallel relation is des1red between the legs of the finished product of the machine.

In the modification of Fig. 5, the profile edge 18:: of the die element D1 is perfectly Straight, and the swaging rollers 25a of the swaging element Sa are arranged in a compound curve of which the mid portion is of a very short radius R and radii R R of the flanking portions of the arc corresponding to those of the first described form. Tn order to preclude the necessity for repetitive description, all the other components of the machine illustrated in Fig. 5, not particularly referred to but having their counterparts in the first embodiment, are identitied by the same reference characters previously employed with addition in each instance of the letter a for convenience of more ready distinction. As a consequence of the shaping of the die element Da and the arrangement of the rollers 25 on the swaging element Sa in Fig. 5, the work piece is bent to U-shaped configuration as before but with a straight portion connecting the legs (of which only one is shown), as will be readily understood from the drawing.

In the further modification illustrated in Figs. 6 and 7, the disks 27b and 28b of the swaging element Sb are formed, medially of the roller supporting edge portions, with cut outs or bights 36 and 37 for insertion of an inset 38 for use in the machine to produce U-shaped work pieces with curved crosswise bar portions B connecting the legs, or for insertion of an inset such as shown and designated 39 in Fig. 8 for use of the machine in bending U-shaped work pieces with straight bar portions con- As shown, the inset 38 of Figs. 6 and 7 comprises plates 40 and 41 which are shaped to fit into the bights 36 and 37 of the disks 27b and 28b, and of which the curved edges correspond to the small radius edge curvatures of the disks 27 and 28 of the first described embodiment. The plates 40 and 41 of the inset 38 are united, with interposition of spacers 42, by means of suitably arranged screws 43, and are secured by means of screws 45 to flange strips 46 and 47 respectively welded fast to the edges of the bights 36 and 37 in the disks 27b and 28b. The rollers 25b carried by the inset 38 function in the same manner as the rollers 25 along the small radius edge portions of the disks 27 and 28 in Figs. 1-4. Here, as before, the same reference characters are used, but with the letter b added for identifying corresponding components.

The insert 39 of Fig. 8 is identical with that of Figs. 6 and 7 except in that the shaping of its plates is such that, when it is substituted for insert 37 of Figs. 6 and 7 and a die element of the type Drz is used, the machine will operate to bend the work pieces to U-shaped configuration with straight cross bar portions connecting the legs in the same way as described in connection with Fig. 5.

Having thus described my invention, I claim:

1. In a bending machine, a rotary support; and an elongate profile die element eccentrically mounted on the support at right angles to a radial line through the axis of the support, with its opposite end portions equally disposed to opposite sides of said line; means on the support for holding a work piece, in the form of a bar or tube, at one end and sustaining the work piece in the plane of the die element with the mid portion of the Work piece contacting the die element; a coplanar rotary support; a swaging element mounted on the coplanar rotary support for bending the work piece to straiglt sided U-shaped configuration about the die element, said swaging element comprising a plurality of rollers to cooperate with the profile edge of the die element in the bending, the rollers being arranged in spaced relation in an arc of compound curvature, having a central portion of a circumferential extent equal substantially to the length of the die element struck from the axis of the coplanar support; and flanking portions flared outwardly to equal extents to opposite sides of the central portion and struck from centers eccentric to the axis of the coplanar support; and means for concurrently rotating the two supports to effect the bending.

2. A bending machine according to claim 1, wherein the die element and the rollers are complemcntally grooved in correspondence with the cross section of the work pieces to be bent.

3. A bending machine according to claim 1, wherein the two supports are in the form of spur wheels; and wherein an intermeshing idler pinion is interposed between said wheels to determine their rotation both in the same direction.

4-. A bending machine according to claim 1, wherein the two supports are in the form of spur wheels; and wherein an intermeshing idler pinion is interposed between said Wheels to determine their rotation both in the same direction; and further including a reversible electric motor for driving one of the wheels; and two switches spaced about said wheel and operable by a peripheral projection on one of the spur wheels to stop the motor upon completion of its rotation in both directions.

5. A bending machine according to claim 1, further including a latch dog eccentrically mounted on the first support adjacent the holding means for releasably engaging the bent distal end of the work piece at the completion of the bending until the finished work piece is ready for removal from the machine.

6. A bending machine according to claim 1, wherein the profile edge of the die element is straight to predetermine a straight connecting cross portion between the legs of the U-shaped product of the machine.

7. A bending machine according to claim 1, wherein the profile edge of the die element is curved concentrically with the axes of its support to predetermine a correspondingly curved connecting portion between the legs of the U-shaped product of the machine.

References Cited in the file of this patent UNITED STATES PATENTS 192,615 Blakey July 3, 1877 447,295 Brenner Mar. 3, 1891 898,424 Bartlett Sept. 15, 1908 1,837,060 Ofiutt Dec. 15, 1931 2,327,706 Halstead Aug. 24, 1943 2,453,868 Shaw Nov. 16, 1948 2,613,720 Baker Oct. 14, 1952 2,723,701 Shaw Nov. 15, 1955 FOREIGN PATENTS 29,113 Great Britain Dec. 9, 1897 457,101 France July 4, 1913 558,203 Great Britain Dec. 24, 1943 604,723 Great Britain July 8, 1948

Images