Clamping jaw arrangement of a thread clamp for textile yarns or the like

A thread clamp for textile yarns or the like comprises two clamping jaw supports which can be moved relatively towards and away from one another. Each of the clamping jaw supports carries a respective clamping jaw. The clamping jaw of one of the clamping jaw supports is constructed as a clamping hood which is seated upon a substantially block-shaped intermediate layer formed of a rubber-elastic or elastomeric material. The intermediate layer has a portion thereof seated in a form-locking fashion in a recess provided at a base plate at said one clamping jaw support. These measures enable particularly realizing an optimum clamping action due to the oscillation-dampening properties of the intermediate layer supporting the clamping surface.

BACKGROUND OF THE INVENTION 
The present invention relates to a new and improved construction of a 
clamping jaw arrangement for a thread clamp for textile yarns or other 
thread-like or filamentary material, which is of the type comprising two 
clamping jaw supports which can be moved relatively towards and away from 
one another, and at each of these clamping jaw supports there is formed a 
respective clamping jaw. 
One such type arrangement has been disclosed in U.S. Pat. No. 3,348,582. 
Here, the clamping jaws are each formed of a rubber block, secured at the 
related clamping jaw support, provided with a subsequently merging steel 
plate and a ceramic or porcelain plate which is mounted upon such steel 
plate. Due to this elastic supporting of the thread clamping surfaces 
there should be prevented the co-oscillations along with the jarring 
effects at the loom which reduces the thread retention force of the thread 
clamping surfaces. 
What is disadvantageous with such clamping jaw arrangements is the 
relatively large mass of the steel plate and ceramic plate upon the 
elastic rubber block. Hence, the entire assembly, with increasing thread 
velocity or in resonance with the loom vibrations nonetheless again begins 
to oscillate, so that in the most unfavourable situation the retention or 
holding force for the thread can drop to null. 
SUMMARY OF THE INVENTION 
Therefore, with the foregoing in mind it is a primary object of the present 
invention to provide a new and improved construction of a clamping jaw 
arrangement of a thread clamp for textile yarns or the like, which is not 
associated with the aforementioned drawbacks and limitations of the prior 
art constructions. 
Another and more specific object of the present invention aims at 
constructing a clamping jaw arrangement of the previously mentioned type 
such that all occurring oscillations, independent of increasing thread 
velocities, at least can be dampened to an uncritical mass or degree and 
the clamping surfaces are maintained in contact with one another to a 
sufficient degree even in the presence of wear. 
Another and more specific object of the present invention is directed to 
providing a new and improved construction of a clamping jaw arrangement 
for a thread clamp for textile yarns or the like, which is relatively 
simple in construction and design, economical to manufacture, extremely 
reliable in operation, not readily subject to breakdown or malfunction, 
and requires a minimum of maintenance and servicing. 
Now in order to implement these and still further objects of the invention, 
which will become more readily apparent as the description proceeds, the 
clamping jaw arrangement of the present development is manifested by the 
features that at least one of the clamping jaws is constituted, in known 
manner, by a wear-resistance support or contact element arranged upon a 
substantially block-shaped intermediate layer formed of a rubber elastic 
or elastomeric material. The block-shaped intermediate layer or element is 
fixedly connected with the related clamping jaw support. The 
wear-resistant support or contact element encloses the intermediate layer 
or element at least partially in a hood-shaped fashion. 
Due to these measures it is now possible to design the inventive 
arrangement so as to be extremely lightweight. This arrangement, by virtue 
of the reduced mass of the hood-shaped support or contact element, 
exhibits an optimum dampening effect. Moreover, the clamping surface, even 
in the presence of extremely high thread velocities, can accommodate 
itself to the thread or other filamentary material, without oscillating or 
vibrating. Additionally, the hood-shaped support element, surrounding the 
rubber block, protects this rubber block against mechanical damage and 
other effects, thereby appreciably increasing the longevity of such rubber 
block. 
Additionally, it is advantageous if the hood-shaped contact or support 
element is fixedly or rigidly connected with the end surface of the 
intermediate layer or element. This can be obtained if the hood-shaped 
support or contact element is inserted upon the intermediate layer or 
element at least with a tight or force fit.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
Describing now the drawings, the conventional construction of thread clamp 
illustrated in FIG. 1 by way of example and described more fully 
hereinafter, has here only been shown intended, for instance, as a thread 
clamp for the transfer of a filling or weft thread tip to a shuttleless 
loom. Of course, the inventive measures and design also can be utilized at 
thread clamps of different construction and having other intended uses at 
the loom. 
According to the showing of FIG. 1, the thread clamp 1 is located near to 
the edge of the woven fabric or cloth 2 in alignment with the weaving shed 
formed by the warp threads 3 of the upper shed and the warp threads 4 of 
the lower shed. The thread clamp 1 has assigned to it the task of 
clampingly retaining a filling or weft thread which has been inserted by a 
not here further shown, but conventional weft thread-insertion element. 
To this end, the thread clamp 1 comprises a pivotal or oscillatory lever 7 
which is connected rigidly for rotation with a rotatable shaft 6 rotatably 
mounted at the loom frame 5. This oscillatory lever 7 constitutes a first 
clamping jaw support or carrier. This clamping jaw support 7 contains at 
its free end an elongate clamping jaw 8 which extends in the direction of 
weft thread insertion. 
The shaft 6 is driven in conventional manner in an alternating direction of 
rotation, in other words is oscillated back and forth, in conventional 
manner in cycle with the movement of the sley of the loom. Hence, the 
clamping jaw support 7 has imparted thereto an oscillatory movement 
indicated by the double-headed arrow 9. 
Rotatably mounted upon the aforementioned shaft 6 is a second clamping jaw 
support 10, which carries at its free end a clamping jaw 11 which extends 
essentially parallel to the clamping jaw 8 provided at the clamping jaw 
support 7. Furthermore, in this arrangement the second clamping jaw 
support 10 possesses in radial spaced relationship from the driven shaft 6 
a pin or journal 12. This pin or journal 12 extends parallel to the shaft 
6 up to the region of the clamping jaw support 7 and piercingly extends 
through such into a cylindrical rubber sleeve or bushing 13 which is 
imbedded in a not particularly referenced bore of the clamping jaw support 
7. With the illustrated embodiment, the mounting or bearing arrangements 
of the rubber sleeve 13 in the clamping jaw support 7 and the pin or 
journal 12 in the clamping jaw support 10 are arranged in offset 
relationship with respect to one another such that the clamping jaws 8 and 
11 resiliently press against one another without the need for any 
additional external action. 
During the pivotal or oscillatory motion of the clamping jaw supports 7 and 
10 to the right of the showing of FIG. 1 the clamping jaw support 10 comes 
into contact with a stationary stop or impact member 14, whereas the other 
clamping jaw support 7 tends to move or pivot further, thereby separating 
the clamping jaws 8 and 11 from one another. As a result, the thread clamp 
1 is opened for the purpose of either receiving or releasing a thread or 
the like. Upon release of the thread such can be taken-over by a simple 
suction nozzle 15. 
Such an arrangement has been described in detail in U.S. application Ser. 
No. 118,641, filed Feb. 4, 1980, entitled "Mechanism on Shuttleless Looms 
for the Transfer of the End of the Weft Yarn". 
Now in order to be able to fulfil the heretofore mentioned conditions, it 
is possible for the clamping jaws 8 and/or 11 to be designed according to 
the illustration of FIGS. 2 and 2A which will be discussed more fully 
hereinafter. 
By reverting to FIGS. 2 and 2A it will be seen that a substantially 
block-shaped intermediate layer 19 formed of an elastomeric or rubber 
elastic material and providing an oscillation dampening element is seated 
upon a base plate 18 provided at the clamping jaw support or carrier 7. 
This block-shaped intermediate layer or element 19 is surrounded in 
straddling fashion by a clamping hood or hood-shaped element 20, for 
instance formed of steel plate which is preferably treated so as to have 
improved surface properties and defines a wear-resistant support element. 
With this arrangement the intermediate layer 19 is preferably seated 
partially in form-locking fashion in a here dovetail-shaped recess 21 
provided at the clamping jaw support 7 or at the base plate 18, 
respectively. The clamping hood or element 20, as illustrated, can be 
fixedly connected with the end surface or face 19a of the intermediate 
layer or element 19, for instance by adhesive bonding or vulcanisation, 
and the entire unit or assembly can guidingly overlap past the extent of 
the base plate 18. Alternatively, the clamping hood 20 also can be 
inserted with a tight fit upon the part of the intermediate layer or 
element 19 which protrudes from the base plate 18. In each case there can 
be obtained a good connection and guiding of the wear-resistant clamping 
hood 20 upon the oscillation dampening intermediate element 19 which, in 
turn, is supported by the base plate 18. 
As further will be recognised by referring to FIG. 2, the clamping hood 20 
is provided at the thread infeed or run-in side with a pronounced infeed 
or run-in edge 22 which is situated opposite a run-in or infeed edge 23 
provided at the clamping jaw 11 of the clamping jaw support 10. 
At this location it is mentioned that the previously described construction 
of the clamping jaw 8 with the intermediate layer or element 19 and 
clamping hood 20 at the clamping jaw support 7 could be equally or 
similarly provided at the other clamping jaw support 10 for the clamping 
jaw 11. 
The undertaken measures first of all allow for an effective dampening of 
the vibrations transmitted by the loom due to the elastic supporting of at 
least one of the clamping surfaces, which additionally can accommodate 
itself in every direction to the thread or yarn and the counter surface, 
resulting in an optimum clamping capability of the thread clamping 
arrangement. Nonetheless, the relative movement between both of the 
clamping surfaces for the purpose of opening the thread clamp need not be 
very large, since the elastic action of the elastomeric intermediate 
layer, upon pressure release, and comparable to a spring, is consumed 
after the shortest movement or stroke. 
While there are shown and described present preferred embodiments of the 
invention, it is to be distinctly understood that the invention is not 
limited thereto, but may be otherwise variously embodied and practiced 
within the scope of the following claims. Accordingly,