WO1999011850A2

WO1999011850A2 - Electronic jacquard mechanism for a weaving loom

Info

Publication number: WO1999011850A2
Application number: PCT/GB1998/002499
Authority: WO
Inventors: Mike Wardle; John Bertram Derrek Rush; Julie Maria Waddle
Original assignee: Bonas Machine Company Limited
Priority date: 1997-08-29
Filing date: 1998-08-20
Publication date: 1999-03-11
Also published as: GB9718219D0; WO1999011850A3

Abstract

An electronic jacquard mechanism including a plurality of elongate heald rods (11) reciprocally movable between an upper shed position (HUL) and a lower shed position (HLL), a selectively operable latch means associated with each heald rod for selectively retaining the heald rod (11) at a desired positioned, each latch means being adapted to frictionally grip the heald rod for retaining it at said desired position.

Description

ELECTRONIC JACQUARD MECHANISM FOR A WEAVING

LOOM

The present invention relates to a jacquard mechanism, in particular an electronic jacquard mechamsm for a weaving loom.

According to one aspect of the present invention, there is provided an electronic jacquard mechamsm including a plurality of elongate heald rods reciprocally movable between an upper shed position and a lower shed position, a selectively operable latch means associated with each heald rod for selectively retaining the heald rod at a desired position, each latch means being adapted to frictionally grip the heald rod for retaining it at said desired position.

According to another aspect of the present invention there is provided an electronic jacquard mechanism including a plurality of elongate held rods reciprocally movable between an upper shed position and a lower shed position, a selectively operable latch means associated with each heald rod for selectively retaining the heald rod at a desired position, the latch means having a first latch formation for co-operation with a second latch formation on the heald rod, the first or second latch formations being movably mounted on the latch means or heald rod respectively.

Various aspects of the present invention are hereinafter described with reference to the accompanying drawings in which: -

Figures 1 and 2 are schematic diagrams of a jacquard mechamsm for use witi the present invention;

Figure 3 is a side view of a first embodiment according to the present invention;

Figure 4 is an exploded perspective view of the first embodiment;

Figures 5a,5b are schematic side views of a second embodiment according to the present invention shown in different operating modes.

Figures 6a,6b are schematic side views of a third embodiment according to the present invention shown in different operating modes.

Figure 7 is a schematic part side view of a fourth embodiment according to the present invention;

Referring initially to Figure 1 there is shown a diagrammatic representation of a heald control mechamsm 10 which includes a plurality of elongate heald rods or hooks 11 (only one being visible in Figure 1) each of which is movable longitudinally between a lower limit HLL and an upper limit HUL of reciprocal motion. Each heald rod 11 is connected at its lower end to a heald eye 12 via a harness cord 14. The heald eye 12 is in turn connected to the frame 15 of the mechanism via a cord 16 and spring 17.

The heald rod 11 includes a stop formation 20 which is urged into abutment with a reciprocating secondary motive drive 50.

The secondary motive drive 50 reciprocates between a lower limit position SLL and an upper limit position SUL.

Reciprocal movement of the secondary motive drive means 50 causes the heald rod 11 to reciprocate between its lower limit position HLL and an intermediate position IP. Preferably the lower limit position HLL is chosen to correspond o the lower shed position for the heald eye 12.

Alternatively, the stop formation 20 may engage a static stop (not shown) for defining the lower limit position HLL and the secondary drive 50 may be located and arranged to contact the heald rods independently of the stop formation 20.

Primary heald rod motive means 30 are provided for moving the heald rod 11 from intermediate position IP toward its upper limit position HUL and subsequently moving the heald rod 11 from its upper limit position HUL toward its lower limit position HLL.

The heald rod motive means 30 preferably comprises a pair of knives 31, 32 which reciprocate along a linear path parallel to the longitudinal axis of the heald rod 11. The knives 31, 32 are located on opposite sides of the heald rod 11 and continuously reciprocate between an upper limit KUL and a lower limit KLL of reciprocal motion; the knives 31, 32 reciprocating 180° out of phase. As is conventional, each knife 31, 32 is elongate and extends along a row of heald rods 11 so as to be capable of moving each heald rod in the row individually. Typically several side by side rows of heald rods and associated knives will be provided.

The knives 31, 32 are each provided with latch means 34 which co-operate wim latch means 35 formed on the heald rod 11.

Accordingly, during reciprocal motion of the knives 31, 32 the co-operating latch means 34, 35 move relative to one another in the longitudinal direction of the heald rod 11 when the heald rod is held stationary. The co-operating latch means 34, 35 are formed such that when the latch means 34 move relative to the heald rod 11 in a direction toward the upper limit HUL they engage with latch means 35 to cause the heald rod 11 to be supported by the knife 31 or 32 on which the engaged latch means 34 are mounted.

The co-operating latch means 34, 35 are also arranged such that when the latch means 34 move relative to the heald rod 11 in a direction toward the lower limit HLL they either automatically disengage from the latch means 35 (if co-operating latch means 34, 35 are engaged) or pass by latch means 35 without engagement.

The latch means 34, 35 are also arranged such that when the latch means 34 on one knife are engaged with latch means 35, the latch means 34 on the other knife are rendered in-operative from engaging the latch means 35. This feature prevents the heald rod 11 when being lowered by one knife travelling toward its KLL position from being engaged and transferred to the other rising knife travelling toward its KUL position as both knives pass one another.

A latch engagement control means 40 associated with secondary motive drive 50 is located in the lower region of the path of reciprocal motion of the knives 31, 32 adjacent to lower limit KLL.

The latch engagement control means 40 serves to control engagement of latch means 34 on either knife 31, 32 with the latch means 35 on the heald rod 11 when the heald rod 11 is retained at its intermediate position IP.

The reciprocal motion of the secondary motive drive 50 is arranged such that the heald rod 11 is raised to its intermediate position IP whilst one or other of the knives 31, 32 are located in the region of their KLL limit position. In this way the latch means 34 formed on one or other knife 31, 32 is located below the latch means 35 in readiness to engage the latch means 35 when the knife 31 or 32 moves relative to the heald rod 11 in a direction toward its KUL position.

The latch engagement control means 40 are arranged such that if the heald rod 11 is retained at its intermediate position IP co-operating latch means 34, 35 engage to cause the heald rod 11 to be moved by the relevant knife 31 or 32 towards its upper limit position HUL. The latch engagement control means 40 are further arranged to prevent engagement of latch means 34, 35 in the event that the heald rod 11 is not retained at its intermediate position IP. In such a circumstance, the heald rod 11 moves towards its lower position HLL with the secondary motive means 50 and so is not raised towards its upper position HUL.

Accordingly all heald rods 11 in the row associated with knives 31, 32 are continuously reciprocated by the motive means 50 between their HLL and IP positions as indicated by arrows RM unless retained at their intermediate position IP and this is achieved by a selectively operable heald rod retention means 51. The retention means 51 on actuation causes co-operating IP latch means 52 formed on the heald rod 11 and a retention latch body 153 of the latch means 51 to engage and prevent movement of the heald rod 11 toward its lower position HLL. Preferably IP latch means 52 and retention latch body 153 are arranged to automatically disengage when the heald rod 11 is moved by a knife 31, 32 toward its upper position HUL.

The heald rod 11 includes a series of US latch means 56 located between IP latch means 52 and latch means 35. Each US latch means 56 is co-operable with retention latch body 153 so as to retain the heald rod 11 at a position adjacent to the HUL position so as to define the upper shed position US for the heald eye 12.

The provision of a plurality of latch means 56 spaced along me length of the heald rod 11 enables adjacent rows of heald rods 11 to be retained at different heights and thereby enable inclined sheds to be produced, ie. sheds which taper in the warp direction. Typically, adjacent latch means 56 are spaced 6 mm apart so that a tapered shed will be produced in stepwise manner at intervals of 6 mm.

It is known for neighbouring knives 31 or 32 of each set to be raised by a different height in order to achieve an inclined shed, ie the knife at the front of the set of knives will be raised by a different height to the knife at the rear of the set of knives.

Accordingly a given knife in a set, needs to raise a row of heald rods 11 to a predetermined height to enable latch body 153 to latch with a predetermined one of the latch means 56.

In practice the actual position KUL reached by a given knife on each stroke may vary due to knife deflection occurring under different loadings applied by the number of heald rods 11 being raised. To ensure that the latch body 153 latches with the desired latch means 56, the position of the latch body 153 is arranged such that when the knife 31, 32 is located at its upper position KUL as calculated under maximum load conditions, the latch body 153 is located between neighbouring upper and lower latch means 56 by a predetermined clearance, , and C₂ respectively in Figure 2.

Typically, for latch means 56 spaced by 6 mm, and C₂ are each at least 1.5 mm.

For certain knives 31, 32 in their respective sets, a clearance of or C₂ of at least 1.5 mm will not be achievable. In this case there is a danger that de-latching of a heald rod 11 from the retention means 51 may not be achievable should for example latching occur on one cycle on a light lift (whereby the latch 153 engages US latch 56') and on the next cycle the knife in question experiences a heavier lift and thereby does not rise sufficiently.

The present invention utilises a single retention means 51 wherein latch body 153 needs to co-operate both with latch means 52 (for retaining a selected heald rod 11 at its IP position in readiness for raising to its upper shed position) and with a predetermined one of the latch means 56 for retaining heald rod 11 at its upper shed position.

Accordingly it is not possible to adjust the height of latch body 153 to ensure correct latching with latch means 56 without also affecting the latching position with latch means 52.

The present invention is particularly concerned with the provision of a jacquard mechanism of the type described above whereby different shed heights for adjacent rows of heald rods may be achieved whilst ensuring reliable de-latching of all heald rods which have been moved to create an inclined shed.

A first embodiment 500 is illustrated in Figures 3 and 4.

In embodiment 500, the series of latch means 56 are mounted on an elongate support body 501 which is slidably mounted on the heald rod 11. Preferably the support body 501 is slidably received within an elongate recess 503 formed i the heald rod 11. The support body 501 has a lower end wall 504 which is biased into contact with a lower end wall 506 of the recess 503 by resilient means 508; the resilient means 508 conveniently being in the form of a compression spring 509 located between an upper end wall 510 of the support body 501 and an upper wall 512 of the recess 503.

In use, as the heald rod 11 moves from its HUL position downwards towards its HLL position, the retention means 51 is actuated and hook 153 enters beneath one of the latches 56 (shown as 56" in Figure 3). At this time support body 501 is at a lower position relative to the heald rod 11 whereat opposed end walls 504, 506 are in contact.

When abutment faces 158, 159 of the hook 153 and latch 56" engage, the heald rod 11 continues to move downwardly causing support body 501 to move upwardly relative to me heald rod 11 thereby compressing spring 509.

The heald rod 11 will thereafter be held at an upper shed position whereat the support body 501 will be located at an upper position relative to the heald rod 11, and whereat opposed end walls 504, 506 will be spaced apart.

In this condition, hook 153 and latch 56 are held in a latched condition due to the relative high loads applied via the supported heald rod 11.

On the next cycle when the knife 31, 32 engages the heald rod 11 to lift it from its upper shed position to its HUL position, loadings applied by the heald rod 11 for maintaining the latched condition are removed.

The shape of opposed abutment faces 158, 159; the materials of construction of these faces; the strength of spring 509; weight of the support body 501; and/or the freedom of sliding motion of body 501 in recess 503 are chosen such that hook 153 is able to de-latch from the engaged latch 56" whilst the heald rod 11 is supported and being lifted by knife 31, 32 toward its HUL position and whilst the support body 501 is located at a position intermediate its upper and lower positions relative to the heald rod 11.

The distance travelled by the body 501 between its upper and lower positions is preferably chosen to exceed the predetermined maximum deflection of the knives 31, 32 between minimum and maximum loadings.

Accordingly, with this arrangement, de-latching of hook 153 and engaged latch 56" can be assured. It is envisaged that spring 509 may be omitted.

A second embodiment 1500 is illustrated in Figures 5a,5b.

The second embodiment 1500 solves the problem of unreliable delatching by movably mounting the hook body 153 for displaceable movement in the direction of motion of the heald rod 11 such that latching engagement occurs when the latch body 153 is at a high position; the body 153 residing at a lowermost position when the heald rod 11 is supported thereby. Accordingly, de-latching occurs at the lowermost position and this ensures mat there is always sufficient over travel by the lifting knives 31,32 to enable reliable delatching to occur.

In Figures 5a, 5b the hook body 153 comprises a body block 1530 which is slidably mounted on a resilient support arm 1531.

The arm 1531 is provided with an upper stop 1532 and a lower stop 1533 which co-operate with block 1530 to define its upper and lower limits H and L respectively of slidable movement.

The arm 1531 normally resides in the position shown in Figures 5a,5b such that latch teeth 1534 on block 1530 lie in the path of travel of latch teeth 56 formed on the heald rod 11. The latch teeth 1534, 56 have co-operating inclined faces 1538, 1539 respectively which engage as the rod 11 is raised and cause the block 1530 to rise to its upper limit position (Figure 5a). Continued upward movement of the rod 11 causes outward deflection of the support arm 1531 as inclined faces 1538, 1539 ride over one another.

When the heald rod 11 descends, latch teeth 1534,56 inter-engage and the block 1530 descends to its lower limit position (Figure 5b) whereat the heald rod 11 is supported by the body 1530 and so continued downward motion of the heald rod 11 is prevented.

For delatching, a solenoid (not shown) is provided for deflecting the arm 1531 away from rod 11.

Preferably the amount of displacement D_x of body 1530 between its H and L limits is chosen to exceed the clearance distance so that when the solenoid is actuated to deflect the arm 1531 for delatching the heald rod 11 is always raised sufficiently high to enable delatching to occur. Preferably the displacement O_l is equal to the clearance distance C_t plus one pitch spacing between latch teeth 1534.

It will be appreciated that the number of teeth 1534 on body 1530 may be less than or more than the four shown in Figures 5a,5b.

A third embodiment 1600 is illustrated in Figures 6a,6b.

Embodiment 1600 is similar to embodiment 1500 in that the latch body 153 is movable such that latching engagement occurs when the latch body 153 is at an upper limit position H (Figure 6a) and delatching occurs when the latch body 153 is at lower limit position L (Figure 6b).

In embodiment 1600, the latch body 1630 is pivotally mounted on support arm 1531 instead of being slidably movable.

The latch body 1630 includes a bearing portion 1631 which is rotatably supported in arm 1531. The bearing portion 1631 includes a stop 1632 which co-operates with arm 1531 to define a lower latch position L (Figure 6b) and upper latch position H (Figure 6a).

The latch body 1630 includes a hook portion 1635 having a lower cam face 1634 and an upper latch abutment face 1636.

In use, as the heald rod 11 rises, latch teeth 56 engage cam face 1634 and cause the latch body 153 to assume its upper limit position (Figure 6a).

As the heald rod 11 continues to rise, abutment faces 159 of latch teeth 56 successively clear terminal edge 1638; the arm 1531 being resiliently deflected thereby.

When the heald rod 11 begins to descend, the abutment fact 159 of the last tooth 56 to have cleared the terminal edge 1638 engages abutment face 1636 of the latch body 1630 and so moves the latch body 153 to its lower limit position L. As with embodiment 1500 the distance D_x by which the latch body 1630 is displaced between upper and lower limit positions is such as to enable delatching to occur.

A fourth embodiment 1100 is illustrated in Figure 7.

The problem of unreliable de-latching of a heald rod 11 retained at its top shed position can only occur if the retention means 51 has to engage with discretely spaced latch means 56.

The fourth embodiment 1100 solves the problem of unreliable delatching by providing latching engagement between the retention means 51 and heald rod 11 which avoids the use of discretely spaced latch means 56.

In the specific construction illustrated in Figure 7 the heald rod 11 is constructed without any latch means 56 or latch means 52. Instead the heald rod 11 has a central planar side wall portion 211 which extends along the length of the heald rod 11 for at least the distance corresponding to that necessary for the retention means 51 to co-operate with the heald rod 11 for retaining it at its intermediate position IP and upper shed position.

The retention means 51 when actuated acts to frictionally grip side wall portion 211 in order to retain the heald rod 11.

In the embodiment illustrated, the retention means 51 includes a wedge 511 slidably received in a housing 512 for movement in the direction of travel of the heald rod 11 between a heald rod engagement position (shown in broken lines) and a heald rod release position (shown in solid lines).

A solenoid 514 is provided for moving the wedge 511 to its heald rod release position. The wedge 511 normally resides in its heald rod engagement position such that the wedge 511 is in sliding contact with the side wall portion 211 and the wedge surface 516 of the housing 512 until actuation of the solenoid 514. Preferably biasing means (not shown) are provided for biasing the wedge 511 to its heald rod engagement position. The biasing means may be a resilient spring or a pair of opposed permanent magnets.

In operation movement of the heald rod 11 in a direction from its lower HLL position to its upper HUL position is permitted by the retention device 51 since such movement tends to urge the wedge 511 toward its release position.

However, movement of the heald rod 11 in a direction from its HUL position toward its HLL position is prevented by the retention means 51 since such movement tends to urge the wedge 511 toward its heald rod engagement position and so causes the wedge to grip the heald rod 11 and prevent further movement in that direction.

The wedge engagement process requires the heald rod 11 to move in the direction toward its HLL position and so the heald rod 11 will move at least a few millimetres before it is locked by the wedge 511. Accordingly the heald rod 11 will always be lifted by the knife 31 or 32 in the next cycle to assist the solenoid 514 to release the wedge 511. If a heald rod 11 which is retained at its upper shed position has to be lowered to its bottom shed position for the next pick, then the solenoid 514 is actuated during the movement of the heald rod 11 to its HLL position.

If a heald rod 11 which is retained at its upper shed position has to remain at its upper shed position for the next pick, then there is no need to actuate solenoid 514 since the heald rod 11 will automatically be retained at its upper shed position.

Claims

1. An electronic jacquard mechanism including a plurality of elongate heald rods reciprocally movable between an upper shed position and a lower shed position, a selectively operable latch means associated with each heald rod for selectively retaining me heald rod at a desired position, each latch means being adapted to frictionally grip the heald rod for retaining it at said desired position.

2. A mechanism according to claim 1 wherein the latch means includes a wedge in contact with the heald rod.

3. A mechanism according to claim 2 wherein the wedge is biased to wedgingly engage the heald rod.

4. A mechanism according to claim 2 or 3 wherein movement of the heald rod in one direction caused the wedge to frictionally retain the heald rod, actuation means being provided which on actuation prevents the wedge from frictionally gripping the heald rod and so permits it to move in said one direction.

5. An electronic jacquard mechanism including a plurality of elongate held rods reciprocally movable between an upper shed position and a lower shed position, a selectively operable latch means associated with each heald rod for selectively retaining the heald rod at a desired position, the latch means having a first latch formation for co-operation with a second latch formation on the heald rod, the first or second latch formations being movably mounted on the latch means or heald rod respectively.