Textiles: weaving – Weft manipulation – Weaving with stationary weft supply
Reexamination Certificate
1998-12-07
2001-01-30
Falk, Andy (Department: 3741)
Textiles: weaving
Weft manipulation
Weaving with stationary weft supply
Reexamination Certificate
active
06179014
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The invention relates to a drawing gripper for a rapier loom fitted with means to receive and to position a filling yarn kept in readiness and resting on a deflection guide.
2. Related Art
In rapier looms, a filling yarn is conventionally made to pass through the shed using a drawing gripper and a receiving gripper. The drawing gripper receives a filling at the intake side of the shed, this filling being kept in readiness by a yarn feeder. When the drawing gripper is being introduced into the shed, the filling is received and positioned inside this drawing gripper and clamped by a clamp. At the approximate middle of the shed, the filling is transferred to a receiving gripper, then clamped by a receiving-gripper clamp and moved by the receiving gripper to the other side of the shed. Meantime the empty drawing gripper returns to its initial position in front of the shed's intake side.
It is furthermore known with respect to rapier looms to move a filling by means of a single drawing gripper through the entire shed. In this case the drawing gripper receiving the filling at the shed's intake side moves toward the opposite shed side where the filling then is released to a receiving hook or the like.
It is known from the U.S. Pat. No. 4,653,544 to make the feeder deposit the filling on a deflecting means in such manner that this filling is kept in a defined position whereat it can be reliably picked up by the drawing gripper when latter is moving toward the shed.
It is known from the European patent document 0 509 255 A1 to fit a drawing gripper (starting at its tip) with a guide surface leading to a transverse slot into which the filling to be received drops. Once the filling has been dropped into this slot, it is no longer able to slip out of it. However only those fillings may be used in weaving that shall easily slip through the slot, so that thick fillings or reinforced fillings cannot be woven at all or only with difficulty. This design has another drawback in that the filling to be received loses all its tension when dropped into the slot and then will remain wholly slack. If the filling positioned inside the drawing gripper is subsequently tensioned by the motion of the drawing gripper, then the load will be applied abruptly. The danger of filling rupture is enhanced thereby.
It is furthermore known from the European patent document 0 441 099 A1 to use a substantially U-shaped plate as the drawing gripper. The crossbar of this U-shaped plate acts as a slide surface for the warp yarns of a lower shed. The leg facing the fabric edge forms a guide surface for the filling to be received and directly guides the filling to a clamp entered by said filling. The other leg also comprises a guide surface and a clearance acting as a positioning device. This design entails the risk that the guide surface of the crossbar facing the fabric edge shall catch a warp moving slightly off-path and shall feed it to the gripper clamp. Warp rupture then inevitably results.
The objective of the invention is to so design a drawing gripper of the above-mentioned kind such that a filling kept in readiness shall be reliably seized and the danger of gripping a warp is substantially reduced.
SUMMARY OF THE INVENTION
This problem is solved in that the drawing gripper subtends a longitudinal cavity which is open both at the front and at the rear and furthermore on the side facing the deflecting element which it encloses.
A readied filling which on account of deflected guidance follows a path clearly different from one that might be followed by a warp can be properly seized by the drawing gripper of the invention and can be reliably received in said gripper. On the other hand there is little risk that the drawing gripper should catch a warp off its proper path. Moreover limitations regarding the dimensions of a filling to be received are absent from the design of the invention.
In the design of the invention, the elements receiving a filling are mounted in various walls of the cavity. As a result, when carried along by the drawing gripper, the filling tension is increased stepwise and the danger of filling rupture is restricted.
In another embodiment of the invention, positioning devices are mounted in two different cavity walls and are mutually separate and opposed. As a result, the drawing gripper keeps a free filling segment in its cavity and hence the segment can be very easily transferred to a receiving gripper or a receiving hook.
In a further example of the invention, the elements receiving, and/or the devices positioning, in the direction of motion of the drawing gripper relative to the position of the readied filling, are offset relative to one another. As a result, the filling tension is raised stepwise when the filling is moved by the drawing gripper and the danger of filling rupture is restricted even further.
The invention provides that the receiving element is fitted with a lip projecting into the drawing gripper and is associated with the positioning device, which in turn is associated with the edge of a fabric being woven, whereby said lip forms a guide surface leading to the positioning device. The drawing gripper side facing the edge of a fabric being woven is at greater risk as regards unwanted pickup of a warp. Because the receiving element, namely the lip, enters the drawing gripper, possible contact between this lip with a warp is substantially precluded.
In another example of the invention, a yarn clamp is present inside the drawing gripper and is mounted at the fabric edge side of the positioning device. This configuration assures that the yarn clamp only will clamp the received filling, and will not be used for any positioning. Accordingly the filling position is defined solely by the positioning device and this filling will always be at the same location and thereby can be reliably transferred to a receiving gripper or receiving hook.
In a further example of the invention, the drawing gripper consists of a substantially U-shaped plate which, as seen in the direction of motion of the drawing gripper, comprises a leg located above the deflection guide and a leg located to the side of the deflection guide. Advantageously in this example, the receiving elements, when viewed in the direction of motion of the drawing gripper, will be configured on opposite sides of the deflection device.
In a further embodiment of the invention, the drawing gripper is fitted with a slide surface associated with guide means guiding a drawing gripper support and/or a gripper band support. This feature enables direct guidance and support of the drawing gripper inside the shed.
Further features and advantages of the invention are elucidated in the following description of illustrative embodiments shown in the drawings.
REFERENCES:
patent: 5129431 (1992-07-01), Stacher
patent: 5819812 (1998-10-01), Bortoli et al.
patent: 5899242 (1999-05-01), Egloff
Bacon & Thomas PLLC
Falk Andy
Picanol N.V.
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