GB2410960A

GB2410960A - Yarn selector mechanism

Info

Publication number: GB2410960A
Application number: GB0403185A
Authority: GB
Inventors: John Dalton Griffith
Original assignee: Griffith Textile Machines Ltd
Current assignee: Griffith Textile Machines Ltd
Priority date: 2004-02-12
Filing date: 2004-02-12
Publication date: 2005-08-17
Also published as: GB0403185D0; BE1017749A3

Abstract

A pile yarn selector mechanism includes a drive means 24, 26, 28 for oscillating a catch member 30 between first and second limit positions, the catch member being movable between an engaged position and a non-engaged position. The catch member 30 in the engaged position engages a yarn carrier 40 to cause the yarn carrier to move as the catch member is moved between its first and second limit positions, the catch when in its non-engaged position being disengaged from the yarn carrier. Selectively actuatable actuation means 36 is operably connected to the catch member 30 to positively move the catch member from its engaged position to its disengaged position, and vice versa. The actuation means 36 may be a piezoelectric strip connected to a power supply.

Description

24 1 0960 YARN SELECTOR MECHANIST\] The present invention relates to a

pile yarn selector mechanism and, in particular, a pile yarn selector mechanism for an Axminster carpet weaving s loom.

In an Axminster carpet weaving loom a plurality of different coloured yarns are fed to a common yarn guiding bar or carrier for each tuft inserting position. The bar or carrier is reciprocated to different positions to enable 0 selection of a desired coloured yarn. A gripper is operable to select a required pile yarn held in the guiding bar or carrier, and the gripper withdraws a length of yarn therefrom. The length of yarn is then cut and the gripper transfers the cut yarn length to the weaving area of the loom where it is placed in the carpet during the weave process.

Grippers and carriers are mounted across the loom, one pair for each pile row of the carpet. Accordingly, there are a large number of grippers and carriers in a given loom. The carriers may be either horizontal or vertical.

An electronic pile yarn selector may be used to select the correct yarn pile.

A pile yarn selector 3 for selectively moving a yarn carrier 1 is known from GB-A-2 286 601, and is shown in Figure 1. The pile yarn selector 3 is reciprocated by an oscillatory shaft 5 and associated lever 6 and connecting rod 7 between a rest position and a selected first position. 2s

The first position of the carrier l is determined by a detent in the form of a spring finger 8 which, when released by an electrically-controlled magnet mechanism 11, drops into a selected notch 9 in the carrier in order to determine which of the pile yarns 2 is aligned with the gripper 4 for so gripping by the latter. Once the selected yarn is pulled, cut and transferred to the loom, the carrier 1 is biased by a spring 10 to the rest position. Once the carrier I has reached its rest position, continued movement of the pile yarn selector 3 results in a relative motion between the spring finecr 8 and the carrier I thereby causing the spring finger 8 to be moved back into s contact with the electrically- controlled magnet mechanism 11, thereby acting to re-set the pile yarn selector..

It is an object of the invention to provide a pile yarn selector mechanism having a catch member for engaging a selected notch in a carrier where the lo catch member is positively driven from an engaged position to a disengaged position and vice versa.

According to an aspect of the invention, there is provided a pile yarn selector mechanism including a drive means for oscillating a catch member Is between first and second limit positions, the catch member being movable between an engaged position and a non-engaged position, the catch member in the engaged position being engageable with a yarn carrier to cause the yarn carrier to move as the catch member is moved between its first and second limit positions, the catch when in its non-engaged position being so disengaged from the yarn carrier; and selectively actuatable actuation means operably connected to the catch member to positively move the catch member from its engaged position to its disengaged position, and vice versa.

as An embodiment of the invention will now be described, by way of a nonlimiting example, with reference to the accompanying drawings in which: Figure I illustrates the operation of a known pile yarn selector mechanism; and Figures 2a and 2b are schematic illustrations of a pile yarn selector mechanism according to an embodiment of the invention.

A pile yarn selector mechanism 20 according to an embodiment of the invention is shown in Figures 2a and 2b.

The pile yarn selector mechanism 20 includes a sliding block 22, which is reciprocated sideways by an oscillatory shaft 24 and associated lever 26 and connecting rod 28 between first and second limit positions.

A catch member 30 is pivotally mounted on the sliding block 22, by means of a pivot pin 32. Preferably, the catch member 30 is formed to define a nose portion 34.

Is The pile yarn selector mechanism 20 also includes actuation means, preferably in the form of a piezo-electric strip 36, to effect pivotal movement of the catch member 30. In the embodiment shown in Figure 2a, the piezo-electric strip 36 is secured at one end to the sliding block 22 and received, at its free end, within an aperture 38 formed in the catch member 30.

The piezo-electric strip 36 is connected to a power supply (not shown) to permit a voltage to be selectively applied across the ends of the piezoelectric strip 36.

When a voltage is applied across the ends of the piezo-electric strip 36, the current induced in the piezo-electric strip 36 causes the strip to bend, as shown in Figure 2b. This, in turn, causes rotation of the catch member 30 on the pivot pin 32.

Once the voltage is removed, the piezo-eleetric strip 36 straightens, causing rotation of the catch member 30 in the opposite direction on the pivot pin 32.

In the embodiment shown in Figures 2a and 2b, the direction of the voltage selectively applied across the ends of the piezo-electric strip 36 causes the free end of the strip 36 to flex downwards. This causes the catch member 30 to rotate in a clockwise direction on the pivot pin 32.

lo It is envisaged that, in other embodiments, the direction of the voltage selectively applied across the ends of the piezo-eleetric strip 36 may be reversed to cause rotation of the catch member 30 in an anticlockwise direction when a voltage is applied across the ends of the piezo-electric strip 36.

In use, the pile yarn selector mechanism 20 is arranged to selectively move one of a plurality of yarn guide members or carriers 40 of which there are many (typically upwards of 1000) in a loom. A single carrier 40 is illustrated in Figure 2a, and includes a plurality of notches 42 formed along an upper edge thereof.

The carrier 40 is movable between a rest position and a first position. The first position of the carrier 38 is determined by the catch member 30 of the pile yarn selector mechanism 20, the nose portion 34 of which is engageable within a selected notch 42 in the carrier 40 in order to determine which of the pile yarns 44 carried by the carrier 40 is aligned with a gripper (not shown).

In the embodiment shown in Figures 2a and 2b, the application of a voltage across the ends of the piezo-electric strip 36 maintains the nose portion 34 of the catch member 30 out of engagement with the carrier 40 (Figure 2b).

When the voltage is removed, straightening of the piezo-electric strip 36 brings the nose portion 34 into engagement with a selected notch 42 in the carrier 40 (Figure 2a).

Once the nose portion 34 is engaged within a selected notch 42, continued lo movement of the sliding block 22 towards its second limit position drives the carrier 38 to its first position where it presents a selected pile yarn 44 to the gripper for gripping by the latter. Once gripped, the selected yarn is pulled, cut and transferred to the loom. At this point, the nose portion 38 may be disengaged from the selected notch 42 by applying a voltage across the ends of the piezo-electric strip 36 (Figure 2b).

The carrier 40 is then returned to its rest position by means of a spring 46, and the sliding block 22 returns to its first limit position.

Claims

1. A pile yarn selector mechanism including a drive means for oscillating a catch member between first and second limit positions, the catch member being movable between an engaged position and a non-engaged position, the catch member in the engaged position being engageable with a yarn carrier to cause the yarn carrier to move as the catch member is moved between its first and second limit positions, the catch when in its non- engaged position being disengaged from the yarn carrier; and selectively lo actuatable actuation means operably connected to the catch member to positively move the catch member from its engaged position to its disengaged position, and vice versa.

2. A pile yarn selector mechanism according to Claim 1 wherein the selectively actuatable actuation means includes a piezo-electric element operably connected to the catch member.

3. A pile yarn selector mechanism according to Claim 2 wherein the piezoelectric element positively moves the catch member to its disengaged no position on the application of a voltage across the piezo-electric element, and positively moves the catch member to its engaged position on removal of the voltage.

4. A pile yarn selector mechanism according to Claim 2 wherein the piezoelectric element positively moves the catch member to its engaged position on the application of a voltage across the piezo-electric element and positively moves the catch member to its disengaged position on removal of the voltage.

5. A pile yarn selector generally as herein described with reference to and as illustrated in Figures 2a and 2b of the accompanying drawings.