GB2092031A

GB2092031A - Improved method of manufacturing belt fasteners

Info

Publication number: GB2092031A
Application number: GB8202424A
Authority: GB
Original assignee: JH Fenner and Co Ltd
Current assignee: JH Fenner and Co Ltd
Priority date: 1981-01-29
Filing date: 1982-01-28
Publication date: 1982-08-11
Also published as: GB2092031B

Abstract

A method of manufacturing a conveyor belt fastener to connect the ends of belting, which reduces the amount of scrap generated during manufacture. The method comprising the steps of feeding a strip of material into a press-tool; impacting spaced portions (1, 3) of the strip to reduce the thickness of at least a part of the strip and thereby to increase locally the width of the strip to its finished dimension (W) trimming a portion of the strip (9) disposed centrally between the spaced portions (1, 3) to reduce the width of the strip; piercing holes (19, 21) in the spaced portions; and separating the fastener from the strip prior to bending the fastener into a substantially U-shape. <IMAGE>

Description

SPECIFICATION Improved method of manufacturing belt fasteners The present invention relates to an improved method of manufacturing belt fasteners.

Belt fasteners, as the name suggests, are used to connect the ends of belting to form a continuous endiess conveyor belt. A known belt fastener comprises a longitudinal metal strip having a substantially rectangular crosssection whose central portion is narrower than the end portions. The strip is bent into substantially U-shaped configuration with the legs of the U-shaped fastener disposed parallel or diverging toward their free ends with respect to one another. A pair of axially spaced apart holes are formed in the free end of each leg and these holes receive the prongs of a Ushaped staple which is used to secure the fastener to the belting. A recess is formed in each free end of the belt fastener between the two axially spaced holes to accommodate either the turned over ends of the staple or the bridge portion connecting the prongs of the staple.

The known fastener is manufactured in the following manner:- Strip material having a rectangular cross-section is fed into a four stage progression tool of a press. At the first stage expansion notches are pierced in the sides of the strip; at the second stage the central portion is trimmed to the required dimension and the recesses, to accommodate the staple, are punched into what willl become the end portions of the fastener. At the third stage the staple holes are formed and finally the ends of the fasterner are trimmed.

The emerging fastener which is still a straight strip is then hardened by heat treatment and plated before being bent into the finished Ushape.

The strip of material from which the fastener is manufactured has a thickness equal to the required finished thickness of the fastener and has a width which is greater than the finished width of the fastener.

This method of manufacture creates considerable scrap material and the need to harden by heat treatment increases the manufacturing costs. Typically the weight of scrap to the weight of the finished component is greater than 1:1.

The finished fastener is required to have a tensile strength of 70 tons and since rectangular cross-section steel strip of this strength is not readily avialable the heat treatment process is necessary.

It is an object of the present invention to provide a method of manufacturing a belt fastener which generates a reduced quantity of scrap.

According to the present invention there is provided a method of manufacturing a belt fastener comprising feeding a strip of material into a press-tool; impacting spaced portions of the strip to reduce the thickness of at least a part of the strip and thereby to increase locally the width of the strip to. its finished dimension; trimming a portion of the strip disposed centrally between the spaced portions to reduce the width of the strip; piercing holes in the spaced portions; and separating the fastener from the strip prior to bending the fastener into a substantially U-shape.

In one embodiment the method comprises the additional step of flattening the central portion of the strip to reduce the thickness thereof prior to trimming the width of the central portion. Conveniently the strip material is round wire having a tensile strength of 70 tons. In a preferred embodiment the round wire is flattened before feeding into the press tool. One advantage of the invention resides in the reduction of scrap since trimming of the spaced end portions of the material is obviated. A further advantage resides in the elimination of the hardening of the fastener when high tensile strength round wire is used.

The invention will now be described further, by way of example only, hereinafter with reference to the accompanying drawings, in which Figures 1 to 3 illustrate respectively, a pian, a partially sectioned elevation and a perspective view of a first embodiment of a belt fastener in accordance with the invention, Figure 4 is a perspective view of a second embodiment of a belt fastener, and Figure 5 is a perspective view of a third embodiment of a belt fastener.

Referring more particularly to the first embodiment illustrated in Figs. 1 to 3, in which Figs. 1 and 2 show the fastener prior to bending into the finished U-shaped belt fastener illustrated in Fig. 3. The belt fastener is manufactured in a press utilizing a four stage progression tool. Material is fed into the tool, from a coil, at one side and the shaped, but still straight, individual fasteners emerge from the other. Four operations are carried out simultaneously but on different parts of the material. After each strike of the tool the material is indexed through the tool to the next stage. The following operations are performed on the material, which in the case of the first embodiment is round wire, between entering and leaving the tool.

Spaced portions 1, 3 of the wire are impacted to flatten the material over this position and to form a recess 5, 7 in each spaced flattened portion. The flattening operation increases the width of the fastener in what will become the end portions, to its finished width W. Tapered end portions 8 are formed simultaneously during this flattening operation. A central portion 9 is trimmed in width to form flat side bearing faces 11, 1 3. A portion 15, 1 7 intermediate the central portion 9 and the flattened end portions 1, 3 is retained in a substantially undeformed state. A pair of holes 19, 21 are pierced in the material within the area bounded by the recesses 5, 7. The fastener so formed is then separated from the material of the coil.

Thus a belt fastener manufactured in accordance with the invention has the advantage that only a very small amount of scrap is generated since utilizing round wire instead of rectangular strip and expanding the width of the material in the end regions means that only a smail amount of material need be trimmed off in the central portion 9. In contrast, with the rectangular strip or known methods of manufacturing both sides of the entire length of the fastener have to be trimmed thus generating considerably more waste material. Following separation of the fastener from the strip it is bent into a substantially U-shape. The inner and outer radial walls 23, 25 of the U-shape end are curved as determined by the cross-section of the round wire from which the fastener is made.

Both sides 27, 29 of the flattened portions 1, 3 are also curved no trimming having been carried out in this region.

In practice the trimming of the central portion 9, the flattening and recessing of the flattened portions 1, 3 and the forming of the tapered ends 8 would constitute one stage of the pressing operation. Piercing of the holes would constitute another stage and trimming to length a further stage. The other stage of the tool being used to cut notches in the material prior to the flattening stage to allow for any expansion of the material during the pressing operation.

Referring now to Fig. 4, a second embodiment is illustrated. This embodiment is essentially identical to the first and the same reference numerals have been used for identical parts, and it is manufactured from round wire.

The difference resides in the shape of the central portion 9 which in this embodiment is flattened to form radially inner and outer faces 31, 33 in the vicinity of the U-shaped bend.

This flattening of the central portion is preferably formed during the pressing operation using one stage of the four stage progression tool. For example it may be done at the same time as flattening the end portions 1, 3 and before trimming of the side faces 11, 1 3.

In an alternative manufacturing method the flattening of the central portion 9 or the end portions 1, 3 and the central portion 9 is performed prior to feeding the material into the progression tool.

The pressed fasteners emerging from the press are subsequently bent into a substantially U-shape.

Referring now to Fig. 5 a further embodiment of the invention is illustrated. Like reference numerals have again been used to identify corresponding parts. In this embodiment the round wire is flattened to form two continuous flat faces 41, 43. The flattening is done prior to feeding the material into the progression tool. In the progression tool expansion notches are cut into the flattened round wire strip at the first stage. The recesses 5, 7 and tapered end portions 8 are formed at a second stage and the holes pierced at a third stage.

The fastener is finally trimmed from the strip.

As with the first embodiment both the second and third embodiments require less material to be trimmed off with the resulting cost saving. The invention has been described with reference to a preferred sequence of operations, but the sequence may be varied for example to suit the number of tool stages or the machine capacity.

Because the belt fasteners are manufactured from round wire which is readily available in the required tensile strength the need for heat treatment hardening is not necessary.

Claims

1. A method of manufacturing a belt fastener comprising feeding a strip of material into a press-tool; impacting spaced portions of the strip to reduce the thickness of at least a part of the strip and thereby to increase locally the width of the strip to its finished dimension; trimming a portion of the strip disposed centrally between the spaced portions to reduce the width of the strip; piercing holes in the spaced portions; and separating the fastener from the strip prior to bending the fastener into substantially U-Shape.

2. A method as claimed in claim 1 further comprising flattening the central portion of the strip to reduce the thickness thereof prior to trimming the width of the central portion.

3. A method as claimed in claim 1 or 2 in which the strip is round wire.

4. A method as claimed in claim 3 in which opposing flats are formed on the round wire prior to feeding into the press-tool.

5. A method as claimed in any preceding claim comprising the additional step of bending the strip into a substantially U-shaped fastener.

6. A method substantially as hereinbefore described with reference to the accompanying drawings.

7. A belt fastener manufactured according to any of claims 1 to 6.

8. A belt fastener constructed and arranged substantially as hereinbefore described with reference to and as illustrated in Figs. 1, 2 and 3 or Fig. 4 or Fig. 5.