GB2271361A - Heald control system - Google Patents

Abstract

A heald control system for loving individual heald rods, (11) to an upper or lower shed position comprises a plurality of stiff heald rods and at least one motive assembly, (31) oscillating between upper and lower positions corresponding to said upper and lower shed positions, the motive assembly including for each individual heald rod selectively actuatable engagement means (33)which on actuation engages the heald rod to connect it to the motive assembly and cause it to be moved toward one of said positions. The engagement means may compromise latching pins (63) selectively actuatable by respective stationary electromagnets (70) or by piezoelectric strips to engage notches (62) in the heald rods (11).

Description

The present invention relates to a heald control system, in particular, a heald control system for selectively moving individual heald rods to an upper or lower shed position.

According to one aspect of the present invention there is provided a heald control system for moving individual heald rods to an upper or lower shed position, the system including a plurality of stiff heald rods, at least one motive assembly oscillating between upper and lower positions corresponding to said upper and lower shed positions, the motive assembly including for each individual heald rod selectively actuatable engagement means which on actuation engages the heald rod to connect it to the motive assembly and cause it to be moved toward one of said positions.

Various aspects of the invention are hereinafter described with reference to the accompanying drawings, in which:- Figure 1 is a schematic diagram of a heald control system according to one embodiment of the present invention, Figure 2 is a more detailed side view of part of a heald control system according to another embodiment of the present invention, Figure 3 is an exploded perspective view showing a portion of the embodiment shown in Figure 2, Figure 4 is a sectional axial view through a first engagement means according to the present invention, Figure 5 is a schematic diagram showing the positional relationship between heald rods and latch drive means, Figure 6 is a sectional axial view similar to Figure 4 of a second engagement means according to the present invention, Figure 7 -is a schematic front view of a carrier having engagement means shown in Figure 6, and Figure 8 is a schematic side view of a third engagement means according to the present invention.

Referring initially to Figure 1 there is shown a heald eye 10 which is connected to a relatively stiff or rigid heald rod or needle 11 via a connection means 13. The connection means 13 may be a short flexible harness or alternatively may be a rigid connection, e.g. an extension of the rod 11. The rigidity of the rod 11 is such that it can be pulled from a lower position LP to an upper position UP and pushed from the upper position UP to the lower position LP by motive means 30. Such movement of the rod 11 causes the heald eye to be moved between lower and upper shed positions LS,US, respectively.

In the case where the connection means 13 is in the form of a flexible harness it will be appreciated that the harness may be in the form of a single cord connected to a single heald eye 10 or may be a plurality of cords connected to a group of heald eyes.

Preferably, a pair of motive means 30 are provided operating 1800 out of phase on individual heald rods 11 to pull or push the heald rod 11 between upper and lower positions UP,LP so that it is possible to eliminate the usual belt and pulley harness system and also provide short harnesses.

The lower portion of the heald eye 10 is connected to biasing means 15, preferably in the form of a spring 16.

In the case of a rigid connection means 13, the purpose of the biasing means 15 is to provide a light tension to hold the heald eye 10 so as not to be deflected during weft insertion; it is not intended to provide the motive force for returning the heald eye to its lower shed position LS.

in the case of a flexible connection means 13, a slightly higher biasing force may be necessary in order to move the heald eye 10 in unison with movement of the rod 11 when it is pushed from its upper UP to its lower position LP.

However, due to the omission of the usual belt and pulley system the inertia caused by such systems is not present.

Accordingly, for both the rigid and flexible connections 13 the load applied by biasing means 15 is relatively light compared to that normally adopted for conventional healds.

In the example shown, the lower shed position LS is defined by the heald rod 11 engaging a fixed stop 18 and preferably a selectively actuatable engagement means 20 is provided. The engagement means 20 is conveniently located near to the stop 18 to engage the lower portion of the rod 11. However, it will be appreciated that the engagement means 20 may be located for engagement with the rod 11 at any convenientSposition along its length. The engagement means 20 is fixedly mounted and includes a latch member (not shown) which in an extended position engages the heald rod 11 and which in a retracted position is clear of the heald rod 11.

Accordingly, when it is intended for the heald rod 11 to remain at its lower shed position LS for weaving, the engagement means 20 is actuated so that its latch member engages the heald rod 11 to hold it at the lower shed position LS. In view of this, the biasing means 15 can be relatively weak as it does not have to provide sufficient load to retain the heald rod 11 against stop 18.

Preferably, each motive means 30 is in the form of motive unit 31 which oscillates inbetween an upper position UP and a lower position LP.

Each unit 31 carries a rod engagement means 33 which is selectively actuated when at its upper position UP or lower position LP in order to engage the rod 11 and move it to the lower position LP or upper position UP respectively.

Prior to engagement of engagement means 33, engagement means 20 is actuated to release the rod 11 to thereby enable it to be moved by an engagement means 33.

When the engagement means 33 has reached its upper position UP, the rod 11 is retained at this upper position, corresponding to the upper shed position, by actuating the engagement means 20 to engage the rod. Alternatively, an additional engagement means 20' may be provided above engagement means 20 for holding the rod 11 at its upper position UP. Immediately after actuation of the engagement means 20 or 20' for holding the rod 11 at its upper position UP, the engagement means 33 is actuated to clear the rod and thereby enable the associated motive unit 31 to move toward the lower position LP.

In the above example the heald rods are normally intended to reside in their lower position and so the motive means is located above the heald eyes. It will be appreciated that the heald rods may be arranged to normally reside in their upper position and that the motive means 30 be positioned below the heald eyes.

A more detailed embodiment of the present invention will now be described with reference to Figures 2 to 6.

In Figure 3 an end portion of a pair of motive units 31 are illustrated, each unit 31 including a support bar 35 from which depend a series of carriers 36. Each support bar 35 is arranged to be driven by drive means (not shown) between the upper position UP and a lower position LP. In Figure 3 the support bars 35 of both units 31 are shown at their upper positions. However, in operation the bars 35 would be driven 1800 out of phase such that when bar 35 of one unit is located at its upper position UP, the bar 35 of the other unit-would be located at its lower position LP.

Each carrier 36 includes a body 37 on which are mounted a group of engagement means 33 arranged in a linear row. In the embodiment shown there are 6 engagement means in each group. There may be more or less than 6 engagement means 33 in each group if desired. Each body 37 is attached to the support bar 35 by a link 39. In Figure 3, the majority of the carriers 36 have been omitted for clarity; the position of the connection of their links to the bar being indicated by holes 40.

Each body 37 is elongate and has opposed side walls defining an upper vertical portion 37a and a lower vertical portion 37b with an intermediate inclined body portion 37c located therebetween which is inclined to the vertical direction. The engagement means 33 of each group are spaced longitudinally along the intermediate portion 37c and so the row of engagement means 33 making up each group is also inclined to the vertical in parallel with the side walls defining the inclined body portion 37c.

Accordingly the horizontal spacing between the centres of adjacent engagement means can be small in relation to the size of the engagement means 33. The horizontal spacing between the centres of neighbouring engagement means 33 corresponds to the spacing between the vertical paths of travel of neighbouring heald rods 11. The bodies 37 are arranged so as to be in side to side contact (not shown in Figure 3) and this ensures that the horizontal spacing between one group of engagement means 33 and the neighbouring group is achieved and maintained in use.

As shown in Figure 4 each engagement means 33 includes a latch member 60 slidably mounted in the carrier body 37 and which is movable between an extended, engaged, position whereat it projects out of the carrier body to engage in a notch 62 formed in its associated heald rod 11, and retracted, clear, position whereat it is located within the body 37 so as to be spaced and disengaged from the heald rod 11.

In Figure 4 the latch member 60 comprises an annular body 61 slidably received in a bore 64, the body 61 having axially mounted therein a relatively small diameter pin 63 for engagement with the heald rod 11. Preferably, the body 61 is a permanent magnet.

To move the latch between its extended and retracted positions at the upper and lower positions UP,LP of rods 11 two assemblies 75,76 of solenoids 70 are provided for cooperation with each motive unit 31. Accordingly an upper assembly 75 of solenoids 70 are provided for actuating latches 60 when at the upper position UP of bar 35 and a lower assembly 76 of solenoids are provided for actuating latches 60 when at the lower position LP of bar 35. The solenoids 70 of each assembly comprise a coil 72 surrounding a soft iron core 73 and these are mounted in groups on brackets 74 of similar shape to bodies 37. the brackets 74 of the upper assembly 75 are supported on a support bar 77 and connected thereto by links 78; the brackets 74 of the lower assembly 76 are supported on a support bar 79 and are connected thereto by links 80.

Adjacent brackets 74 of each assembly 75,76 respectively, nest together in a similar manner to the adjacent carriers 36 so that when the bar 35 is at either its upper position UP or lower position LP, each individual latch 60 will be located adjacent to a respective individual solenoid 70 of the upper or lower assembly 75,76 respectively. This is further illustrated schematically in Figure 5 wherein each vertical line represents a rod 11.

It will be seen from Figure 5 that rods 11 may be closely spaced.

Preferably bars 77,79 are slidably mounted on the loom frame (not shown) so as to enable the vertical spacing and/or orientation between bars 77,79 to be altered for shed adjustment. Adjustment of the orientation between bars 77,79 may be achieved without affecting the horizontal spacing between adjacent solenoids 70 due to sliding contact between inclined slides 70c of brackets 70.

At the upper or lower position of travel, selected solenoids 70 are actuated. If a latch is to be extended, the solenoid is actuated by a short electrical pulse to repel the magnet 61; if the latch is to be moved to its retracted position the solenoid is actuated by a short electrical pulse to attract the magnet. In either event, due to the combined forces of an electromagnet and a permanent magnet, the pin 63 is rigidly moved from one to the other of the positions during actuation of the solenoid.

After firing of the solenoid, the body 61 holds the pin 63 in its extended position by magnetic attraction either with magnetic material in the body 37 located at the end of bore 64 or with the heald rod 11 and in its retracted position by magnetic attraction with say an insert 80 of a magnetically attractable material inserted in the body 37..

An alternative latch is illustrated in Figures 6 and 7 wherein a sliding magnet body 61 is replaced by a magnet body 68 mounted on a resilient rod 69 carrying at its end a pin 63 for engagement with the heald rod 11, the rod 69 being secured at its opposite end 69a on body 37.

A further alternative latch is illustrated in Figure 8. In Figure 8 the latch member is in the form of a pin 63 which is slidably received in a bore 64 in the carrier body 37. One end of the pin 63 is connected to one end of a piezo-electric strip 90. The opposite end 91 of the piezoelectric strip-is secured to the body 37. The strip is of a laminate construction such that voltage applied to the strip 90 causes the strip to deflect laterally along its length and in so doing moves the pin 63 between its extended and retracted positions. Appropriate electrical connections are trailed along the body 37 and support bars 35 in order to connect each individual piezo-electric strip 90 to an electronic control.

Claims (9)

1. A heald control system for moving individual heald rods to an upper or lower shed position, the system including a plurality of stiff heald rods, at least one motive assembly oscillating between upper and lower positions corresponding to said upper and lower shed positions, the motive assembly including for each individual heald rod selectively actuatable engagement means which on actuation engages the heald rod to connect it to the motive assembly and cause it to be moved toward one of said positions.

2. A heald control system according to claim 1 wherein a pair of motive units are provided each having selectively actuatable engagement means engageable with each individual heald rod, one motive unit operating 180 out of phase with the other unit.

3. A heald control system according to claim 1 or 2 wherein the engagement means for each heald rod comprises a latch member movably mounted on the motive unit and electrically actuatable drive means for moving the latch member from a first position whereat it engages the heald rod and a second position whereat it is clear of the heald rod.

4. A heald control system according to claim 3 wherein the electrically actuatable drive means is an electromagnet statically mounted adjacent to the path of travel of the heald rod.

5. A heald control system according to claim 3 wherein the electrically actuatable drive means is a piezo-electric unit.

6. A heald control system according to any preceding claim, wherein a pair of heald rods are connected to one or more individual heald eye for causing movement of the heald eye between upper or lower shed positions.

7. A heald control system according to any of claims 1 to 5, wherein a single heald rod is connected to an individual heald eye for causing movement of the heald eye between upper or lower shed positions.

8. A heald control system according to claim 7, wherein the connection between each single heald rod and its associated heald eye is such as to enable the heald rod to pull the heald eye to one of said positions and to push the heald eye to the other one of said positions.

9. A heald control system according to any preceding claim including selectively actuated heald rod enagement means statically mounted adjacent to the path of travel of the heald rod for retaining the heald rod in the upper or lower shed position whilst the motive assembly is disengaged therefrom.