US2456675A - Tube bender - Google Patents

Description

Dec. 21, 1948. C. J. CHAILLI': 2,4s6,675

I TUBE BE'NDER Filed Jan. 25, 1947 2 Sheets-Sheet 1 Dec. 21, 1948. c. J. cHAILLE 2,455,675

TUBE BENDER Filed Jan. 25, 1947 2 Sheets-Sheet 2 from-frn;

the respective I-beams. The bending dies -20 are designed to swing open in opposite directions as the forming die [6 advances, and the rocking motion of the dies is resisted by a pair of compression Springs 21-21, one for each bending die.

Compression Springs 21 are carried respectively upon shafts 28, the forward end of each shaft including a. block 3| forming part of the shaft. These blocks in turn are Secured to a backing plate 33, which plate bears against the rear surface of dies 20. Plate 33 thus forms a bearing block which, as the bending dies are forced open, engages the swinging edges of the respective dies to spring load them. In this manner the dies back up the tube against the4 pressure of the advancing forming die. g p

In order to stabilize and guide the plate 33 and shafts 28, the rearward ends of the respective' shafts are slidably engaged in a bearing element generally indicated at 35. This element constitutes spaced bearing flanges each having a pair of aligned holes to slidably sustain a respective shaft 28. As shown in Figure 1,y element includes an angle bracket 40 having a vertical limb 4|k and a horizontal limbf42 seated and secured upon the upper web of the respective I-beams l I. A T-shaped member 43 having a horizontal Web 44 secured by welding or other means to the web 42 of angle member 4l, supports the rearward ends of'th'e'shaft 28, while the vertical flange 4| of angle piece 40 supports the forward'portion of the shafts. f It will be apparent that the spaced relationship of the bearing plates 4| and 43 prevents binding of the shafts 28 therein which otherwise might occur; due to lateral forces against the forward ends of the shafts developed in the'sliding of'plate 33 relative to the vhinged bending dies 20-20.

The compression'springs 21 have their rear- Ward ends seated against a plate 36 secured to flangei4l of the angle piece 40 while their opposite ends a're seated against the blocks 31. Upon advance of the ram l4 carrying forming die IG, as *shown vin Figure 5, plate 33 will be forced rearwardly thereby compressing Springs 21 between the blocks 3! and the plate 36. When' the ram reaches the limit' of its stroke it trips control valve lf:l as hereinafter described, stops automatically and retracts 'to its starting position. When this occurs the springs2'l, bearing against bending dies 20, causethe bending dies 'to follow the forming die tolreturn' them to their normal position as shown in Figure 3. This causes the formed tube to be ejxec'ted automatically from the dies. Thev tube may be permitted to dropV into a chute or container or it may be grasped by the operator for manual removal.

' As viewed in Figure'z, each bending die' 20 includes at .one end a pair of lugs 45-45. The inner end of the respective pivot pins 2! are engaged in these lugs and the lugs thus provide an open throat 45 to receive the tube without interf'erence with the pivot pins. In other words, the pivot pins 2I do not extend across the dies since this would interfere With the placing of work in the diesfor in its removal therefrom'. g Referring to'Figure 1, the louter ends of the pivot 'pins 2l are engaged in lugs4l, the lugs being secured to the plate 23,'preferably by welding .V Lugs 41 each include a bore 48 to receivethe pivot pins and to permit the pivot pins to be withdrawn when it is necessary to remove the bending' dies from the machine to beinterchanged with dies of a different size as hereinafter described,

It will be notedthat theforming vdie is of Kil lf ormn'g dies which are supplied with appropriate grooves 5!!v c'orrespoding tofthe' desiredpipeor tubejdiametersl Likewse,fjshould. it be desired semi-circular face contour as viewed in Figure 3 and that the flat faces of the bending dies 20-20 contact the periphery of the forming die when it advances. The advance of forming die IG causes the bending dies 20-20 to rock open in opposite directions by means of their pivotal mounting studs 2| as shown in Figure 5. As viewed in cross section (Figure 4) the forming die and bending dies each are provided longitudinally with a semi-circular groove 50 complementary to each other to provide a circular recess conforming to the diameter of the tube to be bent and closely embracing it. Since the Swinging dies 20 contact the peripheryof forming die [6 at a moving tangential line of contact during the stroke,-the tube is completely enclosed in the bending zone. In other words, the tangential line of contact, as indicated at 51, is located in the bending zone and since the bending operation is progressive, starting at the parting line 52 of dies 20 and working outwardly in opposite directions, the line of contact'progresses with=the bending zone. It has been found that this .arrangement substantially eliminates distortion and fiattening of the tube. Since the dies completely en'circle the tube in the bending zone,- itisprevented from expanding laterally o'fi'the bend as normally occurs. Apparently this causes the metal to flow sufficiently to accommodatethe differential betweenthe inside and outside radius of the bend, producing a swagingfeffect .greatly improving the quality of the work.

It will be apparent that during Vthe' bendingL operation thetube is rigidly. supported at its opposite ends by the vpivot pins 2|,"which support the bending dies IG, although theiiends of the dies are yieldable. As the forming Ldie, advances', the tube begins to bend at itsce'nter outwardly in opposite directions progress'infg toward the pivot pins as the bending dies lfivsw/'in'gli'n opposite directions. Therefore, the major bending forceis resisted by the pivot pins whilefthe pressure exerted by'springs'Z'I serves 4tofmaintain the bendingdies against the forming die toen- 'close thev tube in the bendingv zone.

The. apparatus is capable of bfnclingtubin'g'forl pipes lof'the several standard' commercial sizes ranging for example from 1/4 to1 1/2"- in .diameter and in wall thick'nesfsV up to 1/8. vThis is accomplished by interchanging the bending and to bend'the tube to a smaller or larger radius an forming die IB having-the desired appropriate :face 'radius maybeinstalledin the-ram..l ,It.will

be apparent*- ofy course that the'radisofjthe finished bend will conform to the radius, of forming die l'aslshown in Figure 5.

As previouslyl noted the .angleI of the-bendfis regulated by adjustin'g'the advan ef or forward stroke of the forming die IG relative'to the bending dies. In otherL words, accmplete "return lour U-shaped bend may be formed by causing"v Ithe ram to advance sufiicientlyv to causefltheiline vc'cintact of the bendingfdies to rea'chlth'el center line .of'the semi-circular'forming die, andconversely,

theangle-of the bend may be reduced by limitin'g theadvance of die" l. Adjus'ting meanslare provided which may be rgulatedto's'top thei'ad- Vance accurately atapredetrmined position;

For this. purpose a control rod 55l xtendsforwardlyfrom the control valve 15, having* a'fstop collaru adjustably Secured' on its. forward' end.

.ThissOllafPQOPGFeieS: time-OP .51 Ferries-Py afizsaevzs ram M. Stop 51 oonstitutes a ring 58 engaged on the forward end of the ram and includes a laterally extending arm 59, the outer end of which includes a boss or hub 60 having a bore through Which rod 55 is slidably projected. The rearward end of control rod 55 is slidably mounted in a U-shaped bracket 6| Secured to the top of the hydraulic control unit 15.

The hydraulic control unit serves as a reversing valve to control the supply of hydraulic pressure to the cylinder |2 and includes a hand operated control lever 62. As shown in Figure 3, the control lever is shown in dotted lines in its normal or ram retracting position and is shown in full lines in its ram advancing position. This lever is pivotally mounted as at 63 upon control shaft 64 so as to permit the lever to be rocked in a lateral direction with respect to the U-shaped bracket BI. Bracket 6l includes a notch 65 along its side edge into which the control lever 62 may be engaged. When the lever is swung to the position shown in Figure 3, in engagement in the notch 65, hydraulic pressure is conducted to the cylinder l2 to cause the ram to advance. The advance of th e ram continues until stop hub 66 engages collar 56 secured to the end of control rod 55. Upon engaging the stop collar, the control rod is caused to move forwardly with the ram, compressing spring 66 which is seated between bracket 6l and collar 61 secured t-o the rear end of the control rod. Forward movement of the rod causes the cam segment 68, secured to control rod, to engage control lever and move the same laterally out of engagement with notch 65. When this occurs, tension spring 10, having one end anchored upon bracket 'Il and its opposite end anchored to control lever 62, causes the control lever to snap forwardly to its reversing position whereupon the supply of fluid pressure to the cylinder is reversed causing ram 14 to retraot. This motion will continue until ram M reaches its fully retracted position as shown in Figure 1 whereupon the cycle of operation is ended. It will be apparent, therefore, that adjustment of collar 51 relative to the control rod 55 limits the bending motion of the ram and by so doing regulates the angle to which the tubing is bent. In order to provide a fine adjustment the control rod 55 may be screw threaded at its forward end as at 12 to permit the collar to be adjusted accurately with respect to the rod and may be looked in adjusted position by means of set screw 13.

The machine is operated by placing the pipe or tubing in position in the bending dies as shown in Figure 1, preferably by the provision of a suitable fixture or stop to position the tubing length- Wise relative to the dies. Valve control lever 62 is then rocked manually in a rearward direction to engage the shank of the lever 62 in notch 65 to cause the ram M to advance. The cycle will then continue until hub 60 engages collar 56 to trip the control rod and cause reversal of the ram. Hydraulic pressure is conducted to the valve |5 from a pressure supply system and from the valve to the forward and rearward ends of the hydraulic unit |2 by means of the tubes 14 and 15. Valve I 5 is arranged alternately to supply one or the other of these lines to cause the appropriate ram motion.

It will be noted that having once been adjusted, each succeeding work piece will be identical as to angularity and radius since the advance of the die is uniform for each work piece as controlled by the stop collar 516. Therefore, the apparatus produces work of uniform proportions to meet the required production standards.

Having described my invention, I claim:

1. A tube bending apparatus comprising, a frame, a hydraulic cylinder and ram unit mounted upon said frame, a forming die carried by said ram and adapted to be advanced and retracted by said ram, a pair of stationary bending dies yieldably mounted upon said frame and cooperating with said forming die, a valve for controlling the advance and retraction of said ram and forming die relative to the bending dies to bend the work to a predetermined angle, a manually operated lever on said valve for initiating the advance of the ram, an adjustable trip mechanism associated with said manually operated lever, and a stop element carried by said ram cooperating With said trip mechanism and arranged to actuate the trip mechanism to reverse the position of said manually operated lever and cause the ram to vretract When the forming die bends said Work to a predetermined angle.

2. A tube bending apparatus comprising; a frame, a hydraulically actuated ram carried by said frame, a forming die carried by the ram and adapted to be advanced and retracted by the ram, a pair of stationary bending dies mounted on said frame and arranged to engage the opposite ends of a tube to be bent, said die disposed in alignf ment and having their respective opposite ends pivotally mounted and adapted to open in opposite directions, said forming die having a curved face to determine the radius of a bend and adapted to engage an intermediate portion of the tube, said bending dies having straight faces adapted to engage the curved face of the forming die to provide a progressive bending zone starting at the center of the forming die and progressing outwardly in opposite directions, whereby distance advanced by the forming die relative to the bending dies determines the angle between the opposite ends of the tube, spring loading means on said bending dies to exert a bending pressure against said forming die, a reversing valve having a control lever and adjustable stop means adapted to be contacted by said ram at the end of its stroke, said stop means carrying a cam for engaging said lever and actuating said reversing valve whereby said ram is automatically reversed when said tube is bent to a predetermined angle.

CHARLES JOSEPH CHAILLE.

REFEREN CES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 926,093 Brown June 29, 1909 1,610,196 Blaisdell Dec. 7, 1926 1,948,474 Meyer Feb. 20, 1934 2,246,379 Muir et al June 17, 1941 2,335,809 Stacy Nov. 30, 1943

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