GB2076441A - Improvements relating to tufting machines - Google Patents

Abstract

A tufting machine hook module (11) having a number of hooks (16, 17) embedded within a common cast body member in side-by-side disposition. The hooks are of the staggered type with alternate hooks (16) having a first blade length and the intermediate hooks (17) having a second and different blade length. Preferably, the throats (18) of all of the hooks (16, 17) are transversely aligned so that, when the hooks require regrinding, the throats (18) may be ground as a unit. <IMAGE>

Description

SPECIFICATION Improvements relating to tufting machines The invention concerns tufting machines, and has more particular reference to the tuft-forming instrumentalities thereof.

It is known in the art to provide tuft-forming instrumentalities for a tufting machine intended to produce cut-pile fabric wherein the needles are arranged in staggered relationship on a needle bar and wherein those hooks intended for cooperation with respective ones of the row of needles furthest from the hook bar on which the hooks are mounted have a longer bill than the hooks intended for co-operation with the other row of hooks, the throats of both the long billed hooks and the remaining hooks being an alignment in the longitudinal direction of the hook bar and each hook being secured in position within a respective slot in the hook bar by screw means. A cutting knife is provided for each hook, and the individual knives are similarly aligned transversely of the machine.

It has been found that the transverse pressure applied to the individual hooks by the respective knives can give rise to deflection of the tips of the hooks. The magnitude of the deflection, and, in consequence, the extent to which such deflection adversely affects accurate and consistent pick-up of yarn from the corresponding needle is determined, at least in part by the closeness of the fit of the hook in the slot in the hook bar and by the length of the bill, generally being greater in the case of long-billed hooks.

Having regard to the manufacturing tolerances and clearances which must necessarily be provided, both in connection with the hook bar arrangement and the needle bar arrangement, it sometimes happens that the deflection of the hook tip in any instance is such as deleteriously to affect loop pick-up, with consequential impairment of the uniformity of the tufted fabric.

The primary object of the present invention, according to one of its aspects, is to provide a hook arrangement wherein hook tip deflection is minimised, and, thus, the incidence of loop pickup problems reduced.

According to the present invention there is proposed a hook module for the tuft-forming instrumentalities of a tufting machine which comprises a multiplicity of hooks embedded in a common body part to extend outwardly therefrom in spaced side-by-side disposition, alternate hooks being of a first bill length and intermediate hooks being of a second, and different, bill length.

Although originally proposed to minimize the deflection of the tips of the hooks in tufting machines having a staggered needle construction, the utilization of a modular concept also alleviates the need to provide aligned throats of adjacent hooks, which need existed in the case of individual hooks each mounted in a respective slot in a hook bar. Thus, in the context of a hook module, the hooks may be positioned side-by-side in a module body member with the throat portion of adjacent hooks laterally spaced in the module by the amount of the staggered offset pitch of the tips of the bills or some other convenient amount.

However, difficulties may develop after the hooks have been operating for some time, the action of the knives against the edge of the cooperating hooks giving rise to wear on the hooks. The individual hooks of a module cannot be replaced without destroying the module body member, so regrinding of the Icnife engaging position of the hooks has been proposed. Conventionally hooks have been reground by grinding the face of the hook against which the knife acts to again obtain a sharp cutting edge. However, grinding of the hooks of an integral modular assembly of hooks, especially when the hook gauge i.e., space between adjacent hooks is in the order of less than 0.1 inch, creates difficulties, since there is no adequate space between the hooks for receiving the grinding wheel.

It is, therefore, a supplementary object of the invention to facilitate the re-grinding of the hooks of a staggered hooks module, and thus, in accordance with another aspect of the invention the throats of the hooks are arranged in alignment transversely of the multiplicity of hooks, so that the hooks can be reground in the module.

The invention will now be described further, by way of example only, with reference to the accompanying drawings illustrating one embodiment thereof and in which: Fig. 1 is a front elevation of a first embodiment of the invention; Fig. 2 is a section on X-X of Fig. 1; Fig. 3 is an inverted plan view of the arrangement shown in Fig. 1; and Fig. 4 is a perspective view, partly broken away, of a second embodiment of the invention.

Referring now to the drawings, and particularly to Figs. 1 to 3 thereof, a hook module 11 for the tuft-forming instrumentalities of a tufting machine comprises a plurality of hooks 12, 13 cast integrally with a common body part 14 to extend therefrom in spaced, side-by-side disposition.

Each hook 12, 13 includes a flat shank 1 5 of stepped, generally rectangular form having a bill 16, 17, respectively, extending in the plane thereof to define a throat 1 8 extending parallel to the backs 1 9 of the hook, the back edge of the bill 16, 17, respectively, being aligned with and forming a continuation of the top 20 of the shank.

At its forward end each bill 16, 17 includes a tip 21 for co-operation with a tufting machine needle (not shown) and for the retention of a loop engaged by the hook. The height h of the bill is determined by the height of the loop to be formed.

At its forward end the shank is cut away as at 22 to the stepped configuration shown, so as to provide, during use of the module, clearance for the knives engaged with respective ones of the hooks. A through hole 23 is provided in each shank 1 5 to receive liquid metal during the casting process, thereby to ensure positive and permanent location of the hook within the module.

Hooks 1 2, 1 3 are arranged alternately in the body part and differ only as regards the lengths of the respective bills 16, 17 thereof, the difference in length corresponding to the pitch of the staggered rows of needles provided on the needle bar.

The body part 14 is of rectangular form, and has a depending, apertured attachment flange 24 whereby the module is secured in position, with other like modules, on a looper bar, not shown, there being a triangular web 25 extending between the underside of the body part and the front of the attachment flange at each end of the said body part. A location rib 26 is provided at the rear face of the body part for location of the module on the hook bar.

In the arrangement shown in Figs. 1 to 3, the throats 1 8 and the backs 1 9 of all of the hooks are in alignment in the body part, as too are the backs of the cut-away shank portions 22, the latter being spaced slightly forwardly of the front face of the body part. Similarly the top edges of the shanks 1 5 and hence the backs 27 of the bills 1 6, 17 are in alignment. By virtue of the difference between the bill lengths of hooks 12, 13, one set of hooks extends forwardly of the other, for cooperation with the rearmost row of needles on the needle bar.

We have found that by forming the long and short bill loopers integrally in a common cast (or otherwise formed) body we are able to produce a more stable hook bar assembly and thereby minimise deflections arising from knife loadings, and, in consequence, are able to reduce the incidence of unfavourable conditions in the 'pickup' area of the tuft-forming instrumentalities.

Moreover, by arranging the throats 18 of the hooks 12, 13 in alignment it is possible to regrind all the hooks as a unit when required.

In the alternative embodiment shown in Fig. 4, in which the same reference numerals are adopted for the same or similar parts, the body parts of the long and short bill hooks differ slightly as regards their respective length dimensions, and although the backs of the hooks and of the cut-away shank portions are arranged in alignment, the throats are arranged in slightly staggered relationship.

Claims (4)

1. A hook module for the tuft-forming instrumentalities of a tufting machine comprising a multiplicity of hooks embedded in a common body part to extend outwardly therefrom in spaced side-by-side disposition, alternate hooks being of a first bill length and intermediate hooks being of a second, and different, bill length.

2. A hook module for a tufting machine comprising, a body member, a first and second series of hooks each having a shank, including a mounting portion, and a blade extending from said shank defining a throat therebetween and terminating at a bill, the bills of said first series of hooks being longer than those of said second series of hooks, the mounting portions of all of said hooks being fixed in said body member in spaced side-by-side disposition and having all of said throats transversely aligned, the hooks of said first series being disposed intermediate the hooks of said second series, whereby the bills of said first series of hooks extend beyond the hooks of said second series of hooks, and all of said hooks may be ground as a unit.

3. A hook module as claimed in Claim 1 or 2, wherein said body member is formed by casting metal about said mounting portions, and each of said mounting portions includes an aperture for receiving said metal for permanently locating said hooks in said body member.

4. A hook module substantially as hereinbefore described with reference to and illustrated in Figs.

1 to 3 or in Fig. 4 of the accompanying drawings.