GB2262946A

GB2262946A - Improvements in or relating to tufting machines

Info

Publication number: GB2262946A
Application number: GB9300031A
Authority: GB
Inventors: Harold Brian Bardsley
Original assignee: Spencer Wright Industries Inc
Current assignee: Spencer Wright Industries Inc
Priority date: 1992-01-03
Filing date: 1993-01-04
Publication date: 1993-07-07
Anticipated expiration: 2013-01-04
Also published as: GB9300031D0; GB2262946B

Abstract

In a tufting machine the top shaft (13) which drives push rods of the needle bar by means of eccentrics (21) is removable, thereby to allow selection from a range of top shafts each having fixed eccentrics (21) of respectively different throws according to pile height requirements. The top shaft (13) is drivingly connected with input shaft portions (14, 15) through releasable couplings (16), which maintain a fixed angular relationship therebetween, and the drive (18, 19) to the knife shaft and hook/looper shaft is taken from the input shaft portions thereby to maintain a predetermined timing relationship between the tuft forming instrumentalities. <IMAGE>

Description

IMPROVEMENTS IN OR RELATING TO TUFTING MACHINES The invention concerns improvements in or relating to tufting machines, and has more particular reference to the drive mechanism therefor.

In order to provide a facility for adjustment of the needle stroke of a tufting machine it is conventional practice to include a variable eccentric in the drive transmission path to the needle bar and to adjust the position of the loop forming instrumentalities of the machine to accommodate a change in needle stroke.

It has been found that whilst the versatility arising from the use of variable eccentrics is convenient in a number of regards, such convenience is offset by the increased weight of the arrangement which may, in some circumstances, have a limiting effect on the speed potential of the tufting machine. Furthermore, when the eccentric is adjusted to a position away from its maximum throw the mass of the arrangement is in excess of that dictated solely by the need to provide an eccentric of that specific throw, the compensatory counter balance arrangement being of proportions consistent with the maximum throw of the eccentric.

The object of the present invention is to provide a drive mechanism which maximises the speed potential of the machine in the tufting circumstances obtaining and allows of the use of a counterbalance arrangement more appropriate to those circumstances.

According to the present invention there is proposed a tufting machine having a removable top shaft with fixed eccentric drives, the said top shaft being connectable in predetermined angular relationship with an input drive means and the individual eccentrics being drivingly connected with respective push rods supporting the needle bar.

The drive to the knife shaft and/or hook/looper shaft will ordinarily be taken from the said input drive means, and thus the knife shaft and/or the hook/looper shaft will remain in timed relationship therewith and with the top shaft for the time being drivingly connected with the input drive means.

The invention will now be described further, by way of example only, with reference to the accompanying drawings in which: Fig. 1 is a diagrammatic plan view of a drive mechanism embodying the present invention; and Fig. 2 is a diagrammatic illustration, drawn to a larger scale, showing the connection between the input drive means of the tufting machine and the removable top shaft.

Referring now to the drawings, and in particular to Fig. 1 thereof, a tufting machine includes a main shaft 11 rotatably supported in bearings, not shown, mounted on a machine frame 12 and a top shaft 13 removably connectable with and between aligned spaced portions 14, 15 of the said main shaft.

In order to maintain angular alignment between the top shaft 13 and main shaft portions 14, 15, adjacent ends of the shafts are of half lap configuration, as is shown in Fig. 2, and said adjacent ends are secured together by a split collar 16 arranged coaxially therewith, the cooperating halves of the collar being joined as by bolts 17.

The drive to the knife shaft and/or hook/looper shaft of the tufting machine is taken from main shaft 11, as at 18, 19 respectively, thereby to maintain a predetermined timing relationship therebetween on removal and replacement of the top shaft 13.

The top shaft 13 carries a plurality of eccentrics 21 at spaced locations thereon, each eccentric 21 serving to effect reciprocatory motion of a respective push rod, not shown, and, in turn, of a multiplicity of tufting needles carried by a needle bar supported by the push rods, thereby to cause said needles repeatedly to pierce a backing fabric and, by cooperation with loopers carried on the looper shaft, to form loops at the reverse of the said backing fabric in conventional manner, the loops being cut by knives mounted on the knife shaft or released as uncut loops according to requirements.

In contradistinction to the prior structures, the eccentrics 21 are of a throw determined by a pile height to be produced, and in the event that a different pile height is required, the top shaft 13 is removed by releasing the collar 16 and substituting another top shaft 13 having eccentrics 21 of a different and appropriate throw, the push rod length being adjusted to reflect the change in pile height and to maintain the bottom dead centre position of the needles on reciprocation.

The drive arrangement 11 further includes a contra rotating counter balance shaft 22 driven from the main shaft as at 23, shaft 19 being replaceable or not, as preferred, on change of top shaft.

By means of the invention we are able readily to produce tufted fabrics at a selected one of a range of pile heights with a minimum of adjustment and, more particularly, without any need to adjust the position of the tuft forming instrumentalities, simply by utilising a top shaft having eccentrics of a particular throw and adjusting the push rod length.

The invention is not restricted to the precise detail of the embodiment hereinbefore described, since alternatives will readily present themselves to one skilled in the art. Thus, for example, whilst we prefer to maintain a correct angular relationship between the main shaft and replaceable top shaft by utilising a lap joint connection therebetween, other means for ensuring correct angularity may be used if preferred.

Claims

1. A tufting machine having a removable top shaft with fixed eccentric drives, the said top shaft being connectable in predetermined angular relationship with an input drive means, and the individual eccentrics being drivingly connected with respective push rods supporting the needle bar.

2. A tufting machine as claimed in claim 1, wherein the drive to the knife shaft and/or hook/looper shaft is taken from the said input drive means.

3. A tufting machine as claimed in claim 1 or 2, wherein the said removable top shaft is connected with the said input drive means at each of its ends.

4. A tufting machine as claimed in any one of the preceding claims, wherein the removable top shaft and input drive means are secured together in predetermined angular relationship.

5. A tufting machine as claimed in claim 4, wherein adjacent ends of the removable top shaft and input drive means are of half lap configuration and are secured together by a split collar arranged coaxially therewith.

6. A tufting machine substantially as hereinbefore described with reference to and as illustrated in the accompanying drawings.