GB2147921A - Shedding motion for a travelling wave shed weaving loom - Google Patents

Abstract

A shedding motion comprises rotatably mounted cams (3, 3'), each cam having a pivotally mounted lever (6) with three arms 7, 8, 9. By means of the first arm (7), the lifting lever is mounted to stationary part of the mechanism, the second arm (8) is provided with a roller (10) which engages the cam (3, 3') and the third arm (9) is swingably connected to a tie rod (12) carrying a heald (14). The tie rod is guided for at least a part of its length by a guide (22, 23). The cam pairs are helically arranged and mounted in a housing (24) forming part of the loom frame. A slot (15) is provided in the cam to facilitate assembly and inadvertent disengagement is prevented by a stop (16). <IMAGE>

Description

SPECIFICATION Shedding motion for a travelling wave shed weaving machine The present invention relates to a shedding motion suitable for a travelling wave shed weaving machine.

Weaving machines are known, which weave with a harmonically repeated wave shed, in each wave of which is moved one weft inserter. A plurality of mechanisms was developed particularly for such a machine, these mechanisms forming the wave shed by a wave motion of the healds in which the warp threads are guided.

A shedding motion is known, in which the heald ends are mounted each on one carrier, which is formed along the weaving width by a system of mutually articulated heald rods. The heald rods are, at the points of their articulated joints, moved upwards and downwards with a phase shift, by means of swinging lifting levers which are controlled by reversably rotatable shafts. The reversable rotary motion of the shafts is derived via a lever transmission from front driving cams, the drive of which is coupled with the main shaft of the weaving machine.

This known mechanism shows many disadvantages and deficiencies. It is, above all, considerably complicated in its construction, comprises many elements with clearances in their interconnections, these clearances being increased further by their operation. All this reduces the life and increases the noisiness of the mechanism. The maintenance costs are considerably increased by the increased disturbance rate due to complicated assembly and dismantling. Moreover, the relatively high production costs are not negligible.

The above mentioned disadvantages are considerably mitigated by a shedding motion according to the present invention, which comprises a plurality of rotatably mounted spur cams, each spur cam having a cam path arranged to activate a swingably mounted lifting lever, the lever having a rotatably mounted roller thereon engaging with the cam path the lever connected to a displaceably mounted tie rod carrying a heald wherein each lifting lever is mounted adjacent its cam and is provided with at least three arms of which the first arm is mounted swingably to a stationary point, the second arm is arranged transversally to the cam path of its cam and carries the rotatable roller, while the third arm is swingably mounted to its tie rod which is guided on a part of its length by means of a guide.

The main advantage of the shedding motion according to the present invention consists in its simple design. The small number of transmission elements increases the life and reduces the noise level during operation. The simple construction also substantially reduces the production costs for both small and large scale production. The reduction of the maintenance costs is caused not only by higher life, but also by simplified assembly and dismantling of the machine.

An embodiment of the present invention will now be described by way of example with reference to the accompanying drawings, in which: Figure 1 shows a front view of the shedding motion, Figure 2 is a detailed view in axial section of a spur cam for the shedding motion of Fig.

1, Figure 3, is a detailed front view of a swingable connection of the heald tie rod with the lifting lever for the shedding motion of Fig. 1, and Figure 4 is a detailed cross-sectional view of the swingable connection of Fig. 3.

As shown in Fig. 1, the shedding motion is mounted on a weaving machine frame (not shown) below a plurality of warp threads 1 and 2. The actual shedding motion is formed by a plurality of spur cams, of which for the purpose of simplification, only two spur cams 3 and 3' are shown in Fig. 1, and which are turned for 1 80 degrees relatively to one another, forming one set. For the purpose of forming a wave shed, these sets of cams 3, 3' are arranged along the width of the weaving machine mutually set for example at an angle a = 1 8 degrees relative one another. As the components of the mechanism, which are attached to the front cam 3 as well as those attached to the rear cam 3' are practically the same, they are denoted in Fig. 1 by the same reference symbols and differentiated only by an accent index.The further description of the mechanism relates also to those parts, which are denoted by the index accent. The spur cams 3 are fixed on shaft 4, the drive for which is coupled to the main shaft of the machine (not shown). Each cam path 5 of spur cam 3 has a lifting lever 6, mounted swingably on a stationary part of the mechanism, above its spur cam 3. Each lever 6 is provided with at least three arms 7, 8, 9. The first arm 7 secures the lever swingably to the stationary part of the mechanism. The second arm 8 is arranged transversally relative to the cam path 5 of its cam 6 and carries a rotatable roller 10 which engages in cam path 5. On the third arm 9, tie rod 12 is swingably mounted. Tie rod 1 2 is provided in its upper part with carriers 13, and healds 14 for the warp threads 1, 2.On a part of its length, tie road 1 2 is provided with a displaceable guiding which will be described subsequently. It is advantageous, particularly for reasons of assembly, that each spur cam 3 is provided at the peak point of its cam path 5 in the direction towards the circumference and in an outer ring thereof with a slot 1 5. The size of slot 1 5 accords approximately with that of roller 10 so as to allow the roller to be removed through the slot. However, in order to prevent the roller 10 from slipping out of cam path 5 inadvertantly, the lifting lever 6 is provided in its peak position with a stop 16, mounted on the stationary part of the mechanism.

It is further advantageous, that the swingable mounting of the tie rod 1 2 for healds 14 on the third arm 9 of lifting lever 6 is dismountable. This is shown in Fig. 3, in which the supporting pin 1 7 mounted on the third arm 9 of lifting lever. 6 is provided on its front part with projections 18, 19, which are demensioned so that they can pass through axial recesses 20, 21 in opening 21' of tie rod 12 for the supporting pin 17, in the inoperative position of the tie rod 1 2. This inoperative position is shown in Fig. 3 by dashed lines.

The displaceable guiding of tie rod 1 2 is formed by a guiding groove 22 made in tie rod 12, a guiding pin 23, mounted overhung on a stationary part of the mechanism, the pin engaging with the groove. The guiding groove 22 is advantageously curved to an arcuate shape, of which the radius conforms with that of the swinging path of the swingable mounting of tie rod 1 2 of healds 1 4 on the lifting lever 6. For the purpose of separating the operating area of cams 3 from a dusty environment, the spur cams 3 are mounted in an at least partially closed housing 24, of e.g.

cylindrical shape (see Fig. 1). For the second arm 8 of lifting lever 6, an opening 25 is provided in the housing 24. To obtain an opening 25 of minimum dimensions, the second arm 8 of lifting lever 6 is curved to a circular arc, the centre of which is coincident with the axis of the swingable mounting of lifting lever 6 on the stationary part of the mechanism. The housing 24 can be arranged along the whole width of the weaving machine, between its not represented side walls, and thus form a component of its frame.

Furthermore, a seat 27 is formed on housing 24, on which is swingably arranged lifting lever 6 and to which is fixed a beam 28 which carries a support 29 for the guiding pin 23 for the displaceable mounting of tie rod 12 for healds 14 and the cover 26 for lifting lever 6. Cover 26 is also provided with the stop 16 for lifting lever 6.

Seat 27 is common for at least two lifting levers 6, 6' of one set of spur cams 3, 3'.

The mechanism as specified above operates as follows: The rotary motion of the system of spur cams 3, which are arranged along the width of the weaving machine, is transmitted via rollers 10 to lifting levers 6. On the third arms 9 of lifting levers 6 are mounted tie rods 1 2 which, according to the turning position of the appurtenant cam 3, move upwards and downwards and entrain carriers 1 3 with healds 14 and warp threads 1 and 2. As the sets of spur cams 3, 3' forming part of the cam arrangement, are arranged along the weaving width on shaft 4 with an angular displacement of angle a, healds 1 4 perform a harmonically repeating wave motion. The spur cams 3. 3', turned relative to one another for 1 80 degrees thus cause healds 14 and 14' to take up a mutually opposite position and spread warp threads 1 and 2. In the areas thus formed between warp threads 1 and 2, one weft inserter (not shown) is passed through.

The embodiment of the present invention as specified above is obviously only examplary and can be modified in various manners within the scope of the present invention.

Since beam 28 is about 4 cm wide and because in the machine there are a plurality of such beams arranged one beside the other they form a cover as well as part 26 carrying stop 1 6. Part 26 is also about 4 cm wide and again a series of adjacent parts 26 forms a cover for the levers 6.

Claims (11)

1. A shedding motion, suitable for a travelling wave shed weaving machine, comprising a plurality of rotatably mounted spur cams, each spur cam having a cam path arranged to a actuate a swingably mounted lifting lever, the lever having a rotatably mounted roller thereon engaging with the cam path, the lever connected to a displaceably mounted tie rod carrying a heald, wherein each lifting lever is mounted adjacent its cam and is provided with at least three arms, of which the first arm is mounted swingably to a stationary point, the second arm is arranged transversally to the cam path of its cam and carries the rotatable roller, while the third arm is swingably mounted to its tie rod which is guided on a part of its length by means of a guide.

2. A shedding motion as claimed in Claim 1, wherein each spur cam is provided at the peak point of its cam path in a direction towards the circumference of the spur cam with a slot the size of which is about that of the rotatable roller and is such as to allow the roller to be withdrawn or inserted therethrough, a stop being provided to prevent inadvertant withdrawl of the roller from the cam path.

3. A shedding motion as claimed in Claim 1 or 2, wherein the tie rod on the third arm is disconnectably mounted to the lifting lever and wherein the tie rod is guided by means of a guiding groove in the tie rod, which groove is engaged by a stationary mounted guiding pin.

4. A shedding motion as claimed in Claim 3, wherein the guiding groove in tie rod is curved, and wherein the radius of its curvature corresponds to that of the swingable path of the swingable arrangement of tie rod as mounted to the lifting lever.

5. A shedding motion as claimed in Claim 3 or 4, wherein the disconnectable swingable connection of the rod with the third arm of lifting lever is formed by a supporting pin mounted on the third arm of lifting lever, the pin being provided with projections which correspond with axial recesses formed in an opening in the tie rod so as to allow removal of the supporting pin from the opening in an inoperational position of the tie rod.

6. A shedding motion as claimed in any one of Claims 1 to 5, wherein the spur cams are mounted in an at least partially closed housing preferably of a cylindrical shape, the housing being provided with an opening for the second arms of the lifting levers, a cover for the levers being provided on a stationary part of the motion above the lifting levers.

7. A shedding motion as claimed in any one of Claims 1 to 6, wherein the second arm of the lifting lever is curved arcuately centre of curvature of which coincides with the axis of the swingable mounting of the lifting lever to a stationary part of the motion.

8. A shedding motion as claimed in Claim 1 to 7, wherein a seat is provided on the housing for the swingable mounting of the lifting lever and a part or parts, to which are mounted the guide for the tie rod, a cover for the lifting lever and a stop adjacent an upper position of the lifting lever to prevent inadvertant withdrawal of the roller from the cam path.

9. A shedding motion as claimed in Claim 8, characterised in that the seat is common for at least two lifting levers of one set of spur cams.

10. A shedding motion substantially as described with reference to the accompanying drawings.

11. A travelling wave shed weaving machine having a travelling motion according to any one of Claims 1 to 10.