GB2135921A

GB2135921A - Shaping ends of elongate workpiece

Info

Publication number: GB2135921A
Application number: GB08305458A
Authority: GB
Inventors: Kazuyoshi Sakuma; Tetsuo Nihei; Toshio Maki
Original assignee: Honda Motor Co Ltd
Current assignee: Honda Motor Co Ltd
Priority date: 1983-02-28
Filing date: 1983-02-28
Publication date: 1984-09-12
Also published as: GB2135921B; GB8305458D0

Abstract

An apparatus for working simultaneously both ends of a workpiece W. The workpiece, typically in the form of a bar or a tube is successively shaped by pairs of pre-shaping dies 12a, 12b, shaping dies 14a, 14b and finish-shaping dies 16a, 16b for simultaneously working both ends of the workpiece to a predetermined configuration. The dies in each pair are movable toward and away from the ends of the workpiece in accordance with the operation of a pair of hydraulic devices 20a,20b. A pair of knockout rods 34a,34b,36a,36b,38a,38b, respectively slidably received in cylinders 24,26,28 of the hydraulic devices, co-operate to support the workpiece while the latter is progressively shaped. One of the knockout rods is fixed in relation to one of the dies while the other knockout rod is held afloat relative to the other die by a hydraulic device, so that the workpiece is allowed to stretch at one end thereof. <IMAGE>

Description

SPECIFICATION Apparatus for simultaneously shaping both ends of an elongate workpiece The present invention relates to an apparatus for swaging or otherwise shaping both ends of an elongate workpiece simultaneously. The elongate workpiece applicable to the present invention may for example be in the form of a bar or a tube.

Various apparatuses have been proposed for shaping end portions of workpieces such as bars or tubes, e.g. as disclosed in Japanese Patent Publication No. 47-33430. A problem has existed in these prior art apparatuses in that the ends of a workpiece can only be shaped one at a time and this is time consuming. Another problem is that the workpiece is allowed to stretch at both ends thereof while being shaped, resulting in inaccuracy in the length of the produce, and therefore a substantial time and labour for trimming both ends of the products after the shaping operation. Additionally, the prior art apparatuses generate an objectionable level of noise during operation.

According to one aspect of the present invention an apparatus for simultaneously shaping both ends of an elongate workpiece comprises: a pair of die structures for shaping both ends of the workpiece to a predetermined configuration; a pair of drive means for driving the die structures towards, and away from both ends of the workpiece and a pair of supports for supporting the workpiece during a shaping operation.

Specifically, one of the supports is fixed relative to one of the die structures, and the other support is movably mounted relative to the other die structure to permit elongation of the work-piece by movement of only the end of the workpiece supported by said other support. The other support may be mounted on a hydraulically operated device which allows that support to float under hydraulic control to allow the elongation.

According to another aspect of the present invention apparatus for shaping an elongate workpiece, whilst allowing elongation of its length comprises a pair of supports arranged to engage the workpiece adjacent its ends during shaping by a shaping mechanism, one of the supports being arranged to maintain the associated end of the workpiece fixed in relation to the shaping mechanism and the other support being arranged to float to accommodate the elongation of the workpiece.

The invention may be carried into practice in various ways, but one specific embodiment will now be described, by way of example, with reference to the accompanying drawings, in which: Figure 1 is a sectional plan view of a shaping apparatus embodying the present invention, taken along the line Il-Il of Figure 2; Figure 2 is a side elevation of the apparatus shown in Figure 1; Figure 3 is a front view of a workpiece produced by the apparatus of the present invention; and Figures 4-7 are views similar to Figure 1 but showing the apparatus in sequential stages of the shaping operation.

Referring to Figure 1 of the drawings, a shaping apparatus embodying the present invention is shown and generally designated by the reference numeral 1. The shaper 1 comprises a generally flat and rectangular base or bed 10 adapted to support a bar or like workpiece Win a predetermined set position SP substantially centrally of the length of the bed 10. Workpieces Ware fed intermittently to the set position SP on the base 10 by a conveyor or a manipulator (not shown). Mounted on the base 10 at opposite sides of the set position SP are a first pair of dies 12a and 12b for preliminary shaping, a second pair of dies 14a and 14b for shaping and a third pairs of dies 16a and 16b for finish-shaping. These die pairs are adapted for sequential transfer machining of the workpiece W.

In detail, the dies 12a, 14a and 16a are integrally supported by a base plate 18a and the dies 12b, 14b and 16b by a base plate 18b. The base plate 18a is fixed to the innermost ends of cylinders 24a, 26a and 28a. The cylinder 24a is slidably received in a main hydraulic cylinder (outer cylinder) 22a of a hydraulically operated device 20a which is located to the left of the set position SP in Figure 1, the cylinder 24a serving as a piston rod in the piston and cylinder sense. Likewise, the base plate 18b is fixed to the innermost ends of cylinders 24b, 26b and 28b which oppose the cylinders 24a, 26a and 28a, respectively.

The cylinder 24b is slidably received in a main hydraulic cylinder (outer cylinder) 22b of a second hydraulically operated device 20b which is located to the right of the set position SP, thus serving as a piston rod in the same sense as the cylinder 24a.

With this construction, each base plate 18a or 18b is movable towards and away from the set position SP in accordance with the pressure of hydraulic fluid selectively communicated to passageways 30a and 32a or 30b and 32b, which are formed through the walls of the respective outer cylinder 22a or 22b.

Knockout rods 34a, 36a and 38a are respectively received in the dies 12a, 14a and 16a to be slidable along the axis of their associated dies. The knockout rods are controlled by hydraulic fluid under pressure selectively communicated to passageways 40a and 42a formed through the walls of the cylinder 26a, to passageways 44a and 46a formed through the walls of the cylinder 24a, and further to passageways 48a and 50a formed through the cylinder 28a. The passageway 44a of the cylinder 26a is shown only diagrammatically by a flow line; in practice the passageway 44a could be formed in the cylinder 26a in such a way that pressure to it is communicated via the right-hand end of the cylinder which is clear of movement of the main hydraulic cylinder 22a.The hydraulic fluid under pressure is also communicatable to passageways 40b and 42b formed through the cylinder 26b, to passageways 44b and 46b formed through the cylinder 24b, and further to passageways 48b and 50b formed through the cylinder 28b, to control movement of knockout rods 34b, 36b and 38b which are respectively slidable within the dies 12b, 14b and 16b.

All the knockout rods 34b, 36b and 38b to the right of the set position SP have their rear ends held in constant engagement with the right-hand ends of the cylinders 26b, 24b and 28b, respectively, except for knockout operations. Meanwhile, all the knockout rods 34a, 36a and 38a to the left of the set position SP are kept movably afloat within their associated cylinders by a predetermined level of back pressure which is supplied by a hydraulic device (not shown) to their rear ends, even when they are not performing knockout operations.

A frame member 52a is bolted or otherwise fixed to the bed 10 firmly to support the hydraulic device 20a while movably supporting the cylinders 26a, 24a and 28a. Likewise, a frame member 52b is mounted on the base 10 firmly to support the hydraulic device 20b while movably supporting the cylinders 26b, 24b and 28b.

The die pairs 12a, 12b, 14a, 14b and 16a, 16b are configured successively to machine the workpiece W to the configuration illustrated in Figure 3. As shown, the finished workpiece or product A is made up of an intermediate section mc, tapered sections extending from opposite ends of the intermediate section mc away from each other, and opposite end sections ma' and mb' which are smaller in diameter than the intermediate section mc and at which the tapered sections respectively terminate.

In operation, the workpiece W is located in a position as shown in Figure 1 which corresponds to the pre-shaping die pair 12a, 12b. As a fluid pressure P1 is fed to the chambers of the main cylinders 22a and 22b of the hydraulic devices 20a and 20b via the respective passageways 30a, 30b, all the dies 12a, 1 4a, 1 6a and 1 2b, 1 4b, 1 6b stroke towards the workpiece W at the same time. The dies 12a and 12b firmly grip and pre-shape the opposite ends of the workpiece Was shown in Figure 4.Thereafter, as shown in Figure 4, a fluid pressure P2 is communicated to the chambers at the outer ends of the cylinders 26a and 26b via the respective passageways 40a, 40b as indicated by arrows, while a fluid pressure P3 is communicated to the chambers at the inner ends of the main cylinders 22a and 22b via the respective passageways, 32a, 32b as indicated by arrows. Then, all the dies 12a, 14a, 16a and 12b, 14b and 16b are caused to stroke away from the workpiece W so that the pre-shaped workpiece W becomes clear of the dies 12a and 12b as shown in Figure 5.

A transfer mechanism (not shown) is activated to advance the pre-shaped workpiece W simultaneously with the subsequent retraction of the knockout rods 34a and 34b, to the next shaping position where the coactive dies 14a and 14b face each other.

Further operation of the main cylinders 22a and 22b cause the dies 14a and 14b to move inwardly to the operative position of Figure 6. Subsequently the workpiece W, shaped by the dies 14a and 14b, is shifted further to a position where the finishing dies 16a and 16b are located. The dies 16a and 16b shape the workpiece W to the desired final configuration shown in Figure 7.

While the apparatus of the present invention has been shown and described as progressively feeding a single workpiece W from one work station to another on the bed 10, it will be understood that in practice a train of workpieces W', Wand W"' can be concurrently indexed on the bed 10 as indicated by an arrow 'a' in Figure 7.

In summary, it will be seen that the present invention provides an apparatus which shapes both ends of a workpiece at the same time and thereby remarkably improves the shaping efficiency as compared with conventional apparatuses which works only one end of the workpiece at a time.

While the coactive dies 12a and 12b (14a and 14b or 16a and 16b) shape opposite ends of the workpiece W, they exert the same magnitude of pressure which causes the workpiece W to deform and stretch within the dies. In this instance, because the outer ends of the knockout rods, 34b, 36b, 38b are fixedly located to face the ends of the respective (14b, 16b) the corresponding end of the workpiece W is prevented from stretching beyond the range delimited by these ends of the knockout rods. The workpiece W, therefore, lengthens itself only toward the other dies 12a, 16a into abutment against the knockout rods, 34a, 36a, 38a. As will be recalled, these knockout rods are held movably afloat by the back pressure applied thereto and, accordingly, yield to the deformation of the workpiece W.

Thus, referring to Figure 3 the intermediate larger diameter section mc (inclusive of the opposite tapered sections) and one mb' of the end sections of the product A (see Figure 3) are constantly machined to their predetermined lengths 12 and 13' the dimensional inaccuracy being concentrated in the length 11 of the other end section ma'. It will suffice, therefore, after the workpiece W has been shaped up, to trim the end section ma' with reference to the length 13 of the end section mb'. This substantially halves the time and labour previously consumed in trimming both ends of a workpiece.

Claims

1. An apparatus for simultaneously shaping both ends of an elongate workpiece comprising : a pair of die structures for shaping both ends of the workpiece to a predetermined configuration; a pair of drive means for driving the die structures towards, and away from both ends of the workpiece and a pair of supports for supporting the workpiece during a shaping operation.

2. An apparatus as claimed in claim 1, in which one of the supports is fixed relative to one of the die structures, and the other support is movably mounted relative to the other die structure to permit elongation of the workpiece by movement of only the end of the workpiece supported by said other support.

3. An apparatus as claimed in claim 2 in which said other support is mounted on a hydraulically operated device.

4. An apparatus as claimed in any one of the preceding claims which the drive means comprise hydraulically operated devices.

5. An apparatus as claimed in claim 3 or claim 4, in which the hydraulically operated device(s) com prise hydraulic cylinders.

6. An apparatus as claimed in claim 5, in which the supports comprise knockout rods which are respectively slidably received in the hydraulic cylinders of the drive means.

7. An apparatus as claimed in any one of the preceding claims in which each of the die structures comprise a pre-shaping die, a shaping die and a finish-shaping die.

8. An apparatus as claimed in claim 7, including means for sequentially transferring the workpiece to the pre-shaping dies, shaping dies and finishshaping dies in this order upon completion of shaping at the respective coactive dies.

9. An apparatus as claimed in any one of the preceding claims including a bed on which the die structures, the drive means and the supports are mounted.

10. An apparatus in accordance with claim 9, further comprising a frame member for supporting each of the drive means to be slidable relative to the bed.

11. Apparatus for shaping an elongate workpiece, whilst allowing elongation of its length, comprising a pair of supports arranged to engage the workpiece adjacent its ends during shaping by a shaping mechanism, one of the supports being arranged to maintain the associated end of the workpiece fixed in relation to the shaping mechanism and the other support being arranged to float to accommodate the elongation of the workpiece.

12. Apparatus as claimed in claim 11 in which the shaping mechanism comprises a pair of end dies for simultaneously shaping both ends of the workpiece.

13. Apparatus as claimed in claim 11 or claim 12 in which the supports comprise knockout rods extending one through each end die.

14. Apparatus for simultaneously shaping both ends of an elongate workpiece substantially as specifically described herein with reference to the accompanying drawings.