GB2255785A

GB2255785A - Improvements in or relating to tufting machinery

Info

Publication number: GB2255785A
Application number: GB9207018A
Authority: GB
Inventors: Phillip Harold Crossley
Original assignee: Spencer Wright Industries Inc
Current assignee: Spencer Wright Industries Inc
Priority date: 1991-05-15
Filing date: 1992-03-30
Publication date: 1992-11-18
Anticipated expiration: 2012-03-30
Also published as: GB2255785B; GB9207018D0

Abstract

Improved pattern definition in tufted fabrics produced on dual sliding bar machines is achieved by optimising needle gauge potential, the sets of needles (24, 25) provided on the respective needle bars (26, 27) being more closely spaced in the direction of backing fabric movement than in conventional arrangements and the hook/loopers (22, 23) being of such throat length as to be cooperable with the needles (24, 25) of either needle bar (26, 27). Thus a needle on either bar can cooperate with immediately adjacent loopers or hooks instead of having to be displaced between alternate loopers or hooks allowing a reduction in the pitch of needle bar displacement. <IMAGE>

Description

IMPROVEMENTS IN OR RELATING TO TUFTING MACHINERY The invention relates to improvements in or relating to tufting machinery and has more particular reference to the tuft-forming instrumentalities thereof.

It is well known in the art to achieve patterning effects in a tufted product using plural back-to-back needle bars each carrying respective sets of side-by-side needles, the individual needle bars being separately slidable in the longitudinal direction thereof according to patterning requirements to bring a needle into cooperative register with a hook or looper at a given pitch position.

In conventional arrangements as used in the context of cut pile, the hooks cooperable with the respective sets of needles are of a different length, and the hooks of a given row thereof operate in conjunction only with the needles of a particular needle bar.

Accordingly, for patterning purposes, it is possible to move a particular needle laterally by an amount consistent with a multiple of the pitch at which the needles are set on the relevant needle bar.

This limitation manifests itself in a patterned tufted product as a lack of sharpness in the pattern.

The object of the present invention is to provide a means whereby lateral shift of a needle by an amount equal to the pitch of the needle assembly as a whole, as distinct from that existing in relation only to a single needle bar, might be attained, thereby to give an improvement in the sharpness of the pattern.

According to the present invention there is proposed in or for a tufting machine, tuft-forming instrumentalities including multiple needle bars disposed in back-to-back relationship and each supporting a respective set of needles in uniformly spaced side-by-side array thereon, and a multiplicity of hooks or loopers for selective cooperation with said needles, at least one of said needle bars being movable in the longitudinal direction thereof for patterning purposes, characterised in that the sets of needles of the respective needle bars are located with minimal clearance in a direction transverse to said needle bars consistent with free relative movement therebetween on longitudinal movement of the said at least one movable needle bar and in that the hooks or loopers cooperable with the said needles are of a throat length sufficient for pick-up from needles on either of the said needle bars.

According to a preferred feature, the needle bars are two in number, said needle bars being separately movable in the longitudinal direction thereof under the control of patterning means.

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 diagrammatic illustration of the tuft-forming instrumentalities of the needle configuration of a known tufting machine having two needle bars, the needle bars being separately movable in the respective longitudinal directions thereof; Fig. la illustrates the needle shift potentialities of the arrangement shown in Fig. 1; Fig. 2 is a view corresponding to Fig. 1, and shows the needle/hook configuration of the invention; and Fig. 2a is a view corresponding to Fig. la, and shows the reduced gauge attainable by the present invention.

Referring now to the drawings, and more particularly to Figs. 1 and la thereof, in a tufting machine having a double-needle bar arrangement, the hooks 11 being provided as two sets 12, 13 each to cooperate with a respective set only of the needles 14, 15 of needle bars 16, 17, the hooks of the two sets being of a respective and different throat length, the difference in length being such that the hooks having the longer throat are cooperable uniquely with the front row of the needles 15 whilst the other hooks are cooperable only with the back row of needles 14.

As can be appreciated from Fig. la, whilst the nominal pitch a of the needles when considered collectively is one half of the pitch b of the needles on a given needle bar, needle shift must necessarily be a multiple of the pitch b of the needle on the needle bar being moved, and thus in practice any particular yarn can be moved laterally by a distance which is twice the nominal pitch of the needles as a whole, or a multiple of that distance.

The magnitude of the shift militates against the provision of a sharp edge to a pattern, and this inevitably gives rise to a haziness of the pattern.

In contradistinction to the prior art, the present invention provides a sharpness of pattern not attaihable by prior art structures and gives rise to the creation of a more aesthetically pleasing patterned tufted product.

Thus referring now to Figs. 2 and 2a, in accordance with the present invention the sets of needles 2, 25 in the respective needle bars 26, 27 are arranged in closely spaced disposition in the direction of fabric feed, and the hooks 22, 23 are of a common length sufficient to pick up loops from needles 25 mounted on the front needle bar 27, as considered in the direction of fabric feed. The movement of the loopers 22, 23 in moving towards or away from the needles 24, 25 is increased as compared with the normal movement of-conventional structures by suitable adjustment of the looper drive mechanism.

As is evident -from a consideration of Fig. 2a, the lateral shift of a yarn, given that a particular looper is cooperable with needles on either needle bar, will be a multiple of the pitch a of the needles as considered collectively, and may thus -be equal to that pitch. As has previously been indicated, in the case of the prior art structures, the minimum lateral shift of a yarn is equal to the pitch b at which the needles are set on a given needle bar.

Whilst, in the ordinary course of events, a looper will cooperate with a single needle at each machine cycle, the invention does permit of the possibility of a looper cooperating simultaneously with aligned needles of of the respective needle bars, the intermediate loopers in such situation fulfilling no tuft-forming activity.

The invention is not limited -in its application to the formation of cut pile fabrics wherein the hooks are directed oppositely to the direction of fabric feed, and an analogous arrangement is contemplated for use in producing loop (or uncut) pile, the hooks in such circumstance being oppositely directed.

Claims

1. In or for a tufting machine, tuft-forming instrumentalities comprising multiple needle bars disposed in back-to-back relationship and each supporting a respective set of needles in uniformly spaced side-by-side array thereon, and a multiplicity of hooks or loopers for selective cooperation with said needles, at least one of said needle bars being movable in the longitudinal direction thereof for patterning purposes, characterised in that the sets of needles of the respective needle bars are located with minimal clearance in a direction transverse to said needle bars consistent with free relative movement therebetween on longitudinal movement of the said at least one movable needle bar and in that the hooks or loopers cooperable with the said needles are of a throat length sufficient for pick-up from needles on either of the said needle bars.

2. Tuft forming instrumentalities as claimed in claim 1, wherein the needle bars are two in number, said needle bars being separately movable in the longitudinal direction thereof under the control of patterning means.

3. Tuft forming instrumentalities as claimed in claim 1 or 2, wherein the hooks or loopers are of a substantially common throat length.

4. Tuft-forming instrumentalities as claimed in any one of the preceding claims, wherein the multiplicity of hooks or loopers corresponds in number to the total number of needles provided on the multiple needle bars.

5. Tuft-forming instrumentalities substantially as hereinbefore described with reference to and as illustrated in Figs. 2 and 2a of the accompanying drawings.

6. A tufting machine including tuft-forming instrumentalities as claimed in claim 4.