GB2147320A - Narrow fabric weaving loom - Google Patents

Abstract

A narrow fabric weaving loom has at least two groups 30 of heald frames, the groups of frames being located side-by-side and arranged to be operated by a common cam shaft. <IMAGE>

Description

SPECIFICATION Narrow fabric weaving looms The present invention relates to narrow fabric weaving looms.

It is the general practice in the production of narrow fabric looms to provide a loom having a single group of heald frames which create sheds for a limited number of weaving stations. If a loom having more weaving stations is required it is normal practice to provide a larger loom having a single group of wider heald frames but the increase in width results in slower operational speeds due to instability of the heald frames and increased weight.

It is a general aim of the present invention to provide a heald type shedding system for a narrow fabric weaving loom which enables a weaving loom to be constructed with a large number of weaving stations without sacrificing speeds of operation.

Various aspects of the present invention are hereinafter described with reference to the accompanying drawings, in which: Figure lisa side view of part of a narrow fabric weaving loom showing the heald operating mechanism; Figure 2 is a schematic plan view corresponding to Figure 1; Figure 3 is a front view corresponding to Figure 2 showing the heald arrangement; Figure 4 is a schematic plan view similar to Figure 2 of a different embodiment according to the invention; Figure 5 is a front view corresponding to Figure 4 showing the heald arrangement; Figure 6 is a view similar to Figure 1 showing a further embodiment according to the present invention; Figure 7 is a front view corresponding to part of Figure 6 and showing the heald frame arrangement; and Figure 8 is a perspective view, partly in section, of a group of heald frames according to the present invention.

Referring initially to Figures 1 to 3 there is shown the heald operating mechanism 10 of a narrow fabric loom which basically comprises a cam shaft 12 extending across the width of the loom and a series of heald operating levers 14 spaced along the cam shaft 12. The levers 14 are pivotally mounted on a shaft 18 and each of them is provided with a cam follower 19 which in the illustrated embodiment co-operate with a respective continuous cam chain 20 which are driven by a respective cog wheel 21 mounted on the cam shaft 12. In Figure 1, only three links 20a of chain 20 are illustrated for convenience.

Cam chain 20 is of conventional construction. A cam can, of course, be used in place of the cam chain.

Each lever 14 is provided with a bracket 22 which is pivotally connected by a pin 23 to the respective lever 14. Each bracket 22 projects upwardly from its respective lever 14 and is secured to a rigid T-shaped connecting member 24 which in turn is connected to a respective heald frame 26. Each heald frame 26 is of conventional construction having a pair of side members 26a joined at opposite ends to a pair of cross-members 26b. In a conventional manner heald eyes (not shown) are suspended between crossmembers 26b.

The side members of each heald frame are slidingly supporting in guideways 27 so that pivotal upward and downward movement of each lever 14 causes a linear upward and downward movement of a respective heald frame.

Each lever 14 is biased downwards by a pair of springs 28 attached at one end to brackets 14a and secured at their opposite end to the loom frame so as to bias each heald frame to a lowermost position and bias the cam follower into contact with the cam chain 20 and maintain contact therewith during rotation of the cam shaft.

As seen in Figures 2 and 3 two groups 30 of heald frames 26 are provided side-by-side, there being up to 16 heald frames per group. As shown schematically in Figure 3, each group of heald frames functions to create sheds for two weaving stations W1, W2 and each group of heald frames can be operated to weave different or the same fabric pattern. Additionally each group of heald frames may be arranged to operate a different number of weaving stations.

Accordingly by using a common cam shaft and arranging groups of heald frames side-by-side to be operated by the cam shaft as described above it is possible to provide a narrow fabric weaving loom which employs the same basic parts as associated with a loom having a single group of heald frames but yet has the versatility of either producing at the same time a variety of fabric patterns or high production rates for weaving the same fabric pattern. By adopting the above principle it is possible to have more than two side-by-side groups of heald frames.

When the cam shaft 12 is provided with cam chains as opposed to conventional cam discs the versatility of the loom is increased since it enables the operator to alter the cam chains and thereby alter the fabric pattern.

A further embodiment is illustrated in Figures 4 and 5 wherein the same heald operating mechanism is employed but wherein pairs of levers 14 are used to operate a single wider heald frame 35. As seen in Figure 4 ten pairs of levers 14c, 14dare provided for operating ten heald frames. In this arrangement the cam shaft 12 is conveniently provided with cam discs only which are arranged in pairs to simultaneously operate an associated pair of levers 14.

Each heald frame 35 has side members 36 slidably guided in guideways 37 and cross-members 38 between which heald eyes (not shown) are suspended in a conventional manner. The connecting member 24 for each heald frame 35 has a pair of depending connecting arms 24a which are connected to respective brackets 22 of said pair of levers.

A central support member 39 is provided which at a central location along the cross-members extends between the cross-members and is connected to the connecting member 22. The support member 39 is slidably supported in a guideway 40 and thereby serves to stabilise fore and aft deflections of the heald frame during use and thereby enables the heald frames to be oscillated at relatively high speeds.

The pair of connecting arms 24a for each heald frame are positioned symmetrically either side of the mid position of the heald frame so that upward and downward forces imposed on the frame by said arms are balanced and do not therefore cause the frame to twist. This gives the heald frame an ability to be operated at high speeds. The spacing between arms 24a for each heald frame differs per heald position in proportion to the spacing between the associated pair of operating levers 14a, 14d.

As seen in Figure 5 the heald frames 35 are illustrated as creating sheds for six weaving stations W1 to W6. Since displacement of each heald frame is shared by 2 levers ther inertia created during use is also shared which enables the loom to run at higher speeds before the cam followers begin to bounce on the cam discs i.e. reach a speed whereat the biasing force on the levers is insufficient to maintain contact between the cam discs and cam followers.

The width of the heald frame may assume wider dimensions than heretofore. It will be appreciated that by providing more than one support member and associated guideway it is possible to increase the width of the heald frame still further. If need be more than two cams may be used to operate a single heald frame providing the position of the arms 24a co-operating with the cam is such as to provide balanced forces about the centre position of the heald frame.

Referring now to Figures 6 to 8 there is shown a heald frame 100 which includes a central body portion 110 having laterally extending upper and lower arms 112 which project from both sides thereof. A plurality of heald eyes 114 are suspended between the arms 112. The body portion 110 is in the form of a frame having a pair of side members 116 connected to end members 117. The body portion 110 also includes a depending portion 113 to which a chord 119 may be attached. The opposite end of the chord 119 being attached to a pivoted lever 120 operated by a cam follower 130.

The entire body portion 110 is preferably moulded in one piece from a suitable plastics material with the arms 112 being in the form of metal strips which are embedded in the body portion during moulding thereof. Advantageously the plastics material is reinforced to give added strength. A suitable reinforced plastics is a carbon fibre reinforced polyamide.

At the junctures between the side and end arms there are provided laterally projecting lugs 136 which collectively define a guide passageway for a guide plate 138.

In use a series of heald frame 100 are located side-by-side as indicated in Figure 8 with a guide plate 138 being interposed between adjacent heald frames 100. The adjacent plates 138 are spaced apart by means of a spacing element 139 which is located in the space framed by side and end members 116 and 117 respectively. Through bolts (not shown) extend through the guide plates and spacing elements 139 and secure the assembly to a frame support 140 of the loom. Accordingly, each heald frame 100 is suspended from support 140 and is free to slide up and down relative thereto.

Each heald frame 100 is biased to an uppermost position by biasing means 144. In view of the lightness in weight of each heald frame and therefore creates a relatively small inertia when compared to comparabie conventional heald frames the biasing means 144 is conveniently in the form of an elasticated webbing having a clip 142 at one end for connection to a support arm 146 and a clip 143 at its opposite end for connection to the upper arm of a respective heald frame.

As indicated above, each heald frame is connected buy a chord to a pivoted lever 120 having a cam follower 130. The cam follower 130 is biased into contact with a cam disc 131 mounted on cam shaft 132 by virtue of the upward bias created by biasing means 144.

The cam shaft 132 and levers 120 therefore operatethehealdframes 100 in a similar manner to cam shaft 12 described with reference to Figure 1 with the exception that the operating lever is biased to an upper position rather than a lower position.

The heald frames 100 may be arranged in a single group or as illustrated in Figure 7 may be arranged to define a pair of side-by-side groups 150 of heald frames. This construction has all the advantages of the embodiment described with reference to Figures 1 to 3 with the added advantage of being capable of operating at far higher speeds.

It will be appreciated from the above that all embodiments incorporate the principle of using a single cam shaft which has two or possibly more cams arranged to operate one heald guide position.

As in the embodiments of Figures 1 and 7 there may be more than one heald frame per heald position or there may be a single heald frame per heald position as in the case of the embodiment of Figure 5.

Claims (11)

1. A narrow fabric weaving loom including at least two groups of heald frames, the groups of frames being located side-by-side and arranged to be operated by a common cam shaft.

2. A loom according to claim 1 wherein the cam shaft includes individual cam discs mounted thereon for operating a respective heald frame.

3. A loom according to claim 1 wherein the cam shaft drives individual cam chains for operating a respective heald frame.

4. A narrow fabric weaving loom having a group of heald frames, each heald frame having upper and lower cross-members between which a plurality of heald eyes are suspended, the upper and lower cross-members being joined at respective ends by a pair of side members each of which is slidably received in a guide for guiding movement of the heald frame, a cam shaft having a plurality of cams thereon for moving each heald frame, each heald frame including a plurality of depending connection members spaced apart along the length of the frame, each connecting member co-operating with a respective cam on the cam shaftfortransmitting movement from the cam to the heald frame, the spacing between the connection members of each heald frame being chosen so that twisting moments imposed on the frame by a given connection member is balanced by the other connection members.

5. A loom according to claim 4 wherein the connection members of each heald frame are joined to a common cross-memberwhich is connected to the side members.

6. A loom according to claim 5 wherein for each heald frame at least one support member is provided intermediate the side members, the or each support member being connected to each crossmember of the frame and to the said common cross-member, the or each support member being slidably received in a guide so as to restrain fore and aft deflections of the heald frame.

7. A heald frame comprising a central body portion having laterally extending upper and lower arms which project from both sides of the body portion for suspending a plurality of heald eyes therebetween.

8. A heald frame according to claim 1 wherein the body portion is provided with channel forming formations which co-operate with the body portion of neighbouring heald frames to define therebetween a channel for the reception of a guide element.

9. A heald frame according to claim 7 or 8 wherein the body portion is a plastics moulding.

10. A narrow fabric weaving loom substantially as described with reference to and as illustrated in Figures 1 to 3 or 4 and 5 of the accompanying drawings.

11. A heald frame substantially as described with reference to and as illustrated in Figures 6 to 8 of the accompanying drawings.