DE8913622U1 - Gripper projectile with insert bodies - Google Patents

Description

Gebrüder Sulzer Aktiengesellschaft, Winterthur, Switzerland

Gripper project with insert bodies

( ) The invention relates to a gripper projectile according to the preamble of claim 1 and a weaving machine with such projectiles.

In known projectiles of the type specified, the weft thread clamp is rigidly connected to the housing on the yoke. The two weft thread clamp arms lie freely within the housing walls. As has been shown in practice, vibration phenomena occur on the clamp arms. These are partly excited when the projectile is fired; partly they are also caused by corrective changes in direction that the projectile guide exerts on the projectile as it passes through the shed. Such vibrations can impair the functional reliability of the thread clamp by causing the clamping jaws to bounce against each other and/or rub against each other, thus resulting in the risk of the thread being lost during insertion. Suggestions have already been made as to how this problem of thread loss can be mitigated.

From CH-PS 657.644 a weft thread clamp is known, the yoke of which is provided with an opening in which a spring body made of, for example, an elastomer is mounted, which enables a non-rigid fastening of the

2 -

Clamp on the carrier body. This non-rigid fastening is a first measure to reduce the risk of losing the thread. Another measure is known from the copyright certificate Sü 1406238. There it is proposed to insert a plastic insert between the clamp arms, which touches the inner flanks of the clamp arms.

However, the known measures do not reduce the frequency of thread loss to an adequate extent. It is therefore the object of the present invention to create means to further alleviate the problem of thread loss by combining already known measures and their inventive further development.

The invention solves this problem with insert bodies as described by the features of the characterizing part of claim 1. Such insert bodies make it possible to attach the weft thread clamp to the carrier body without rigid connections. As a result, shocks that act on the projectile are transmitted to the weft thread clamp in a dampened manner, and the vibrations are thus reduced. In addition to the causes, the consequences are also influenced: the coupling that the insert bodies create between the housing and the weft thread clamp effectively dampens harmful vibrations caused by hard impacts.

Various advantageous embodiments of the insert bodies are characterized in more detail by the features of the dependent claims to 9.

The invention is explained in detail below with reference to the figures. They show:

Fig.1

Fig. 2a

Fig. 2b

Fig. 2c

Fig.3

Fig. 4a

a grapple projectile,

a weft thread clan of the projectile,

a first insert body for weft thread wrapping of Fig.2a,

a second insert body,

the base part of a weft clamp, in which the yoke is enclosed by an insert body,

a yoke with a specially designed opening and

Fig. 4b

an insert body for the yoke of Fig.4a.

The weft thread clamp 2 is built into the gripper projectile 1 in Fig. 1 - this is a projectile according to the state of the art. This is fastened with rivets 4 in the housing 3 designed as a carrier body. The projectile holds the thread 5 with its weft thread clamp.

The most important parts of the weft thread clamp 2 are shown in Fig. 2a: the two clamp arms 21, the clamping jaws 22 and the yoke 23 with openings 4 for fastening the clamp to the carrier body. The point 25 on the inside of the clamp arms 21 is also shown, where the opener inserts to spread the clamp arms apart.

Fig.2b shows an insert body 30 according to the invention, which fits with one end 31 into the fork at the base of the weft thread clamp 2 in Fig.2a. The insert body 30 should consist of an elastically flexible material such as nitrile rubber (NBR), which has a damping effect thanks to high internal friction. In order to dampen vibrations of the clamp arms, it is expedient to make the width c of the insert body 30 slightly larger than the space between the clamp arms 21 at the corresponding point, namely the distance c in Fig.2b. In this way, during relative movements between the clamp arms 21, the insert body 30 always remains in a positive connection and can thus dissipate the energy associated with the vibration through internal friction. It is advantageous to provide a tapering on the part 32 facing away from the end 31, so that gap-like gaps remain open between the insert body 30 and the clamp arms 21. The material pressed together in the part 31 can thus move slightly in the direction of the part 32. In addition, the spreading torque that the insert body 30 exerts on the clamp arms 21 can also be kept small.

The insert body 30 creates a pulse-transmitting connection between the housing 3 and the weft thread clamp 2, through which the vibration-damping effect of the insert body 30 is increased. The fastening of the insert body 30 to the carrier body is carried out, for example, by two nose-like extensions 33, which engage in a form-fitting manner in groove-like recesses in the carrier body and in this way create an anchoring in the housing wall. Of course, the reverse is also possible, namely that the extensions are located on the carrier body.

and the corresponding recesses are recessed in the insert body.

Another possibility for anchoring is that the insert body 30 is provided with an opening 34, as shown in Fig. 2c, and that it is fastened to the housing 3 with a rivet.

In the examples considered above, the insert body 30 is attached to the weft thread clamp 2 simply by pressing the insert body into the fork between the two clamp arms 21. In order to be able to rule out the possibility of the insert body 30 slipping out of the fork in the longitudinal direction, the clamp arms 21 can, for example, be given a suitable shape: curved clamp arms can create a bottleneck that prevents the correspondingly shaped insert body from slipping out. As with the attachment to the carrier body, an anchor can be made using extensions on one side and corresponding recesses on the opposite side.

Fig.3 shows the head part of a projectile with the upper half of the casing removed. Only the base region of the clamp arms 21 is visible and the insert body 30 is not shown either. The yoke 23 of the weft thread clamp is covered by an insert body 40, which in turn is enclosed in close contact by the casing wall. The openings 24' are not intended for fastening the weft thread clamp to the carrier body, but merely serve to establish good contact between the yoke 23 and the insert body 40 by parts of the insert body 40 engaging in these openings 24'. The fastening of the

Weft thread clamp 2 can be made by means of a riveted insert body according to Fig.2c or also with insert body 30 according to Fig.2b, if the anchoring in the carrier body is sufficiently resistant.

In Fig.4a and Fig.4b a variant of the embodiment of Fig.3 is given. The yoke 23 is provided with a
specially designed opening 26 into which the insert body 41 can be inserted. The two openings 44 serve to attach the weft thread clamp with rivets 4 as in the projectile of Fig.l. The appendage-like part 45 of the insert body 41 bridges the
Space between yoke 23 and housing 3; its task is to exert a shock-absorbing effect.

Claims (9)

a a a a a Protection claims: 1. Gripper projectile for weaving machines, with a housing designed as a hollow body and a weft thread clamp built into it, which consists of a pair of spring-elastic, pre-stressed clamp arms and a yoke connecting them at the base, "characterized in that at least one insert body (30; 40, 41) made of damping and elastically flexible material connects the weft thread clamp (2) and the projectile housing (3) by means of positively locking contact-mediating parts (31, 33) and that an insert body (30) is at least partially embedded in a positively locking manner at the base of the two clamp arms (21) between them. 2. Projectile according to claim 1, characterized in that the insert body (30) between the clamp arms (21) engages with at least two nose-like extensions (33) in recesses of the projectile housing (3). 3. Projectile according to claim 2, characterized in that the insert body (30) fills at least half of the space between the clamp arms (21), whereby it is partially compressed and partially separated from the clamp arms (21) by gap-like gaps. 4. Projectile according to one of claims 1 to 3, characterized in that the clamp arms (21) are provided with curvatures which form a bottleneck and that the insert body (30) is at least partially embedded in a form-fitting manner between the clamp arms (21) in this bottleneck. ■ • * · · · ·
· · · · 5. Projectile according to one of claims 1 to 3, characterized in that the insert body (30) between the clearing arms (21) has at least one opening (34) with a fastening means with which it is fastened to the projectile housing (3). 6. Projectile according to one of claims 1 to 5, characterized in that the yoke (23) of the weft thread clamp (2) is at least partially encased by an insert body (40), which in turn is at least partially positively held by the projectile housing (3) in the head region. 7. Projectile according to one of claims 1 to 6, characterized in that the weft thread clamp (2) is attached to the yoke (23) in the head region of the projectile (1) on the projectile housing (3). 8. Projectile according to claim 7, characterized in that an insert body (41) is mounted between the yoke (23) and a rigid fastening element of the projectile housing (3) and that this insert ( bearing body (41) has a part (45) with which it at least partially fills the space between the yoke (23) and the housing wall (3). 9. Projectile according to one of claims 1 to 8, characterized in that at least one insert body (30; 40, 41) consists of nitrile rubber.