GB2213410A - Pipe bending apparatus - Google Patents

Abstract

The apparatus, for forming serpentine pipes, includes a base frame 1 for supporting a pipe or pipes to be bent and capable of rotating about a column 3 in opposite directions; a plurality of retractable forming rolls 10-1 to 10-5 at bending positions; and a pressure jig 13 for bending a pipe or pipes to be bent and including a gripper rod 13' cable of detachable engagement with a respective forming roll in each bending step. A pipe or stacked pipes are fed to a stop 5 and clamped 7. The rod 13' by means of a pin which cooperates with roll 10-1, is held whilst the frame 1 is rotated through 90 DEG to bend the pipe(s). Successive applications of the rod 13' at the respective rolls with attendant frame rotation produce a serpentine pipe form, the free pipe end always extending in one direction. <IMAGE>

Description

PIPE BENDING APPARATUS The present invention relates generally to pipe bending apparatus and, in particular, to an apparatus fr forming serpentine pipes having bends with a rectangular C form. Such serpentine pipes are suitable for use in heat exchanger units such as condensers of the type used with electric refrigerators or air conditions, the heat exchanger units being constituted by serpentine thin retail pipes each having a pipe diameter of about 10 or less.

Japanese Patent publication NO. 17311/1975 and Japanese Patent Laid-open No. 110426/1984 disclose pipe bending apparatus for forming a serpentine pipe having straight portions and arcuated bends which are curved at a predeterrnined curvature.

However, in order to for a serpentine pie having straight portions and bends each constituted by two corners which the pipe is bent at an angle of 90G, it is necessary to change the axial orientation of the proximal portion of the pipe with respect to each portion to be bent.

Therefore, in each bending step, the setting of tne pipe must be changed. This leads to various problems suck. as an increase in the number of bending steps, an increase in the nurber of time-consuming operations, and a lowering in operability.

Cne object of the present invention is to provide a pipe bending apparatus of simple and inexpensive construction and, further, which is simple to operate.

Another object of the present invention is to enable a plurality of pipes to be bent together and at the same so considerably improving productivity and thereby reducing the production costs.

In accordance with the present invetion, we propose pipe bending apparatus comprising a table for supporting a pipe or pipes to be bent and mounted for angular displacement about an axis perpendicular to the table, between predetermined bending positions, a plurality of forming rolls at least some of which are retractable form a bending plane defined by the table, and a bending jig adapted to cooperate with successive forming rolls to bend the pipe or pipes as the table is displaced from one bending position to the next.

A preferred embodiment of apparatus for bending pipes in a serpentine form comprises a support; a bar member carried on the support; a base frame supported at its substantial centre by the bar member for rotation about its axis of rotation in opposite directions in a horizontal plane; beams disposed across the base frame such that the beams are spaced apart from each other by a distance equivalent to the distance between breadthwise opposing bends of the pipes to be worked in a serpentine form; a plurality of forming rolls extending through the beams and movable upwardly and downwardly at a position below the topes of the beards; a plural iZ-# of 1 If ers connected to the lower portions of the forming rolls and operable to cause the forming rolls upwardly and downwardly in interlocking relationship with the motions of the lifters; a pressure jig including a gripper rod having an engagement pin at its one end, the engagement pin being detachably engageable with the axial holes formed in the forming rolls for rotation abouts its axis within the axial holes; and a pressure roll located at its intermediate portion between opposite ends.

Other features and advantages of the present invention will be apparent from the following description by way of a preferred embodiment. Reference is made to the accompanying drawings in which: Figure 1 is a diagrammatic plan vie: of bending apparatus for forming serpentine pipes, and illustrates E manner in which a plurality of pipes which are superimposed anc partially bent are set on the apparatus; Figure 2 is an elevation on arrow X in Figure 1; Figure 3 is a longitudinal sectional view of a forming roll in its retracted lower position; Figure 4 is a view similar to Figure , shewing the forming roll portion in its operating upper position; Figure 5 is a plan view of a pressure jig which, in use, is engaged with a forming roll;; Figure 6 is a part cross-section along A-A in Figure 5; and Figures 7A to 7H are illustrations of the process sequence for bending pipes in a serpentine form.

Referring to Figures 1 to 6, a base frame 1 is supported at its centre of mass by a cross bar member 4 which stands on a support column 2, and is pivotable about a vertical axis passing through the centre in opposite directions in a horizontal plane. A stop 5 disposed in the vicinity of one corner of the base frame 1, serves to secure a guide merber 6 having an engagement groove to the portion of the base frame 1 adjacent to the stopper 5, thereby to locate one end of each pipe P and to secure a plurality of pipes P one above the other as shown. h chuck 7 which is near a position immediately before a first position at which the pipes P are to be bent, comprises for example, a hydraulic or pneumatic cylinder 8 or a toggle clamp for clamping the plurality of pipes P. Cross-bearts 9 and 9' on the base frame 1 are spaced apart from each other by a distance corresponding to the distance between breadthwise opposing bends of the pipes P to be worked in a serpentine form.

A plurality of forming rolls 101, 102 ... extend through the beams 9 and 9' at least the second roll 1 2 and subsequent rolls being movable by devices li 113 ... such as cylinders or toggle clamps, acting on a lower part of the rolls 102, 105 etc. vertically between a bending position and a retracted position below the tops of the beams 4 (i.e.

outside of a bending plane). If desired, the first forming roll 101 alone may be fixed. Pressure plates 12 are vertically movably cisposeci or. the base frame 1 at s##-at'e positions thereof immediately before each bending position.

Alternatively, as shown in Figures 3 and 4, the pressure plates 12 may be attached to some of the forming rolls suitably positioned such that the pressure plates 12 and the forming rolls may be integrally movable upward and downward. A pressure jig 13 comprises a gripper rod 13' separately from the base frame 1, a pressure roll 1@ attached to the gripper rod 13' intermediate its ends, and a engagement pin 15 projecting form one end of the rod 13'. During bending, as the base frame 1 rotates, the pressure jig 13 moves in sequence from one forming roll 101, 10 ... to the next the rolls having been previcusly advanced to their bending positions.At each bending position, the pressure jig 13 detachably engages with an axial hole in the top of the forming roll 101, 1G, and is operable at each bending position to press the plurality of pipes P against the corresponding forming roll to accurately form a desired bend.

The pressure jig 13 is held at a substantially fixed position by an operator in the above-described engaged state, the relative position of the pressure jig 13 with respect to each forming roll, and hence precise angle of each bend to be formed in the pipes P being set, by stopper 16 on the base frame 1, limiting further rotation thereof. The stopper 16 is set so as to compensate for any spring back of the pipes P.

Figures 7h to 7H bear arrows indicating the direction in which the base frame 1 is rotated to progress from ore bending step to the next in a sequence for bending pipes P in a serpentine form.

Ir. operation of the apparatus, the plurality of pipes P which are laid one of top of the other on the bar members 4 are secured by the chuck 7. The first forming roll 101 vif movable) is moved to its bending (i.e. upper) pos tion while the other forming rolls 102, remain in their retracted (lower) positions. The pressure jig 13 is engaged with the first forming roll 151, and the base frame 1 is then rotated in the direction indicated by the arrow in Figure 7A the pressure jig 13 being held stationary.

The base frame 1 is shifted to the position shown in Figure 78, thereby completing a first bending step. Subsequently, at the position shown in Figure 7B, the pressure jig 13 is moved into engagement with the second forming roll 102 which has been advanced to its upport position. While the pressure jig 13 is held stationary, the base frame 1 is next rotated in the direction indicated by an arrow shown in Figure 7C, to the position shown in Figure 7D, thereby effecting a second bending step.

Then, at the position shown in Figure 7E, the pressure jig 13 is moved into engagement with the third forming roll 103 which has been advanced to its upper position.

The pressure jig 13 is again held stationary and the base frame 1 rotated in the direction indicated by the arrow s= in Figure 7E to the position shown in r figure 7@, thereby effecting a second bending step.

Then, at the position shown in Figure 7E, the pressure jig 13 is moved into engagement with the third forming roii 10 which has been advanced to its upper position. The 3 pressure jig 13 is'again held stationary and the base frame 1 rotated in the direction indicated by the arrow shown in Figure 7E to the position shown in Figure 7F, thereby effecting a third bending step.At the position of Figure 7F, the pressure jig 1J is moved into engagerrert with the fourth forming roll 10 which has been advanced to its upper position and, with the pressure jig 13 once again held stationary, the base frame 1 is rotated in the direction indicated by the arrow shown in Figure 7G, to the position shown in Figure 7H, thereby effecting a fourth bending step.

The pipes F are thus sequentially bent in a serpentine from by a combination of alternate rotations of the base frame 1 through 1800, the advancement in turn of each of the forming rolls 101 102 ... at the bending positions, and the action of the pressure jig 13 which, detachably engages with the appropriate forming roll in each bending position.

After completion of all the bending steps, the forming rolls 101, 102 .. and the pressure plates 12 provided separately from or integrally #ith these forming rolls are retracted from the tops of the bar members 4. Simultaneously, the chuck 7 is released and the pipes P which have beer.

bent in a serpentine form are -emcve.

As described previously1 a bending apparatus for forking serpentine pipes includes he base frame 1 having the structure which enables the base frame 1 to rotate in a plane in opposite directions; the movable structure constituted by the plurality of forming rolls 1011 1 2 which are disposed at the bending positions for movement in upward and downward directions; and the pressure jig 13 constituted by the gripper rod 13' capable of moving in engagement with the forming roll in each bending step.In the apparatus of the present invention, the frame base 1 can be alternately rotated in opposite directions to bend the pipes P in a serpentine form while they are being fed forwardly without the need to swing the unworked straight portions of the pipes P. n addition, it is possible to bend the plurality of srimposed pipes P collectively and at the same time. Therefore, productivity can be improved to a remarkable extent, thereby reducing the cost of products. Also, the a -s-e-described arrangement makes the mechanism of the bending apparatus extremely simple and hence inexpensive. Sir.ila~~y, workability is improved by its simple operation. It ill therefore be understood from the foregoing that the present invention provides a very useful bending apparatus for forming serpentine pipes.

Claims (7)

1. Pipe bending apparatus comprising a table for supporting a pipe or pipes to be bent and mounted for angular displacement about an axis perpendicular to the table, between predetermined bending positions, a plurality of forming rolls at least some of which are retractable from a bending plane defined by the table, and a bending jig adapted to cooperate wit successive forming rolls to bend the pipe or pipes as the table is displaced from one bending position to the next.

2. Apparatus according to claim 1 wherein the table comprises a horizontal base frame including a bar memebr carried upon a vertical support disposed at the centre of the table such that the table is angularly displaceable in opposite directions about a vertical axis through the centre.

3. Apparatus according to claim 1 or cial 2 wherein the table comprises beams cisposed across a base frame and carrying said forming rolls which are spaced apart to correspond with the intended distance between bends to be formed in the pipe or pipes.

4. Apparatus according to any one of the preceding claims wherein the forming rolls extend through the table and are retractable to a position below a pipe supporting surface of the table by devices connected to the lower ends of the forming rolls.

5. Apparatus accorc-ro to any one of the preceding claims wherein the bending jig comprises pressing means including a gripper rod that is detachable engageable with successive forming rolls in the bending plane for angular displacement relative thereto and has, intermediate its ends, a pressure roll for cooperation with a forming roll to bend the pipe or pipes.

6., An apparatus for bending pipes in a serpentine form comprising a support; a bar member carried on the support; a base frame supported at its centre by the bar member for rotataion about an axis passing through the centre for rotation in opposite directions in a horizontal plane; beams disposed across the base frame and spaced apart from each other by a distance equivalent to the distance between breadthwise opposing bends to be formed in the pipes; a plurality of forming rolls extending through the beams and movable upwardly and downwardly at a position below the tops of the beams; a plurality of devices connected respectively to lower portions of the forming rolls ano operable to move the forming rolls upwardly and downwardly; a pressure jig including a gripper rod having a pin at one end, the pin being detachably engageable within axial holes formed in the forming rolls to permit relative angular displacement of the gripper rod and forming rolls; and a pressure roll located intermediate the ends of the roc.

7. Pipe bending apparatus constructed and arranged substantially as hereinbefore described with reference to and as illustrated in the accompanying drawings.