Textiles: weaving – Weft manipulation – Weaving with stationary weft supply
Patent
1995-06-20
1997-02-11
Falik, Andy
Textiles: weaving
Weft manipulation
Weaving with stationary weft supply
74 8915, D03D 4712
Patent
active
056011210
DESCRIPTION:
BRIEF SUMMARY
TECHNICAL FIELD
The present invention relates to a device for controlling the gripper straps on looms, and in particular for controlling, according to a desired law of motion, both a positive and negative weft carrying gripper on a continuous weft feed loom.
BACKGROUND ART
Known devices for controlling the gripper straps on continuous weft feed looms consist, as e.g. shown by FR-A-2303876, of a connecting rod-crank drive mechanism for translating along a straight guide a slide fitted with means for engaging a variable-pitch worm screw mounted in idle manner parallel to, and on a support integral with, the guide. The screw is thus rotated, by the reciprocating translatory movement of the slide, so as to transmit a reciprocating rotatory movement, to a toothed pinion fitted angularly integral with the screw, and which in turn, and in known manner, controls translation of a flexible gripper strap wound partially about the pinion.
Known devices of the aforementioned type, though they do provide for varying the law of motion of the gripper strap by means of a relatively straightforward mechanical operation on the device itself, and for gradually taking up any slack between the screw profiles (or threads) and means for reading/engaging the same, are nevertheless mechanically complex, expensive to produce, and unreliable, particularly as regards the reading/engaging means which normally consist of idle rollers with an oblique axis in relation to the screw.
DISCLOSURE OF INVENTION
It is an object of the present invention to provide a straightforward, reliable, relatively inexpensive device for controlling the gripper straps on continuous weft feed looms, and which provides for taking up any slack in the straps. It is a further object of the present invention that the above device should be easily adaptable for enabling variations in the law of motion of the gripper strap and so converting the negative gripper control device into a positive gripper control device and vice versa, with no need for specialized (only trained) personnel, and in a relatively short space of time (2-3 hours).
According to the present invention, there is provided a device for controlling the gripper straps on continuous weft feed looms, and of the type comprising a connecting rod-crank drive mechanism for controlling translation of a slide along a straight path defined by fixed guide means; a worm screw parallel to said path and mounted in idle manner on a fixed support integral with said guide means, the worm screw being fitted to a pinion controlling the gripper strap; and a nut screw carried by the slide and having worm screw reading means by which it engages the worm screw for rotating it as a consequence of translation of the slide along said path; the nut screw comprising at least two half elements each having said worm screw reading means, these means being adjustable relative to the worm screw in order to maintain a desired level of slack; characterized in that: movable relatively in relation to each other along the worm screw axis; slide and by a nut screw body for relatively displacing in opposite directions said half elements of the nut screw, such that any slack between respective worm screw threads and said reading means can be taken up.
According to a first embodiment of the present invention, the half elements consist of two half shells formed by longitudinally sectioning the nut screw along a diametrical plane of the worm screw. A first half shell is mounted in axially fixed manner, while the other is mounted in axially movable manner, and presents an opening in which is inserted in axially slack manner a spherical-wedge-shaped cam varying angularly in axial thickness.
According to a second embodiment of the present invention, the half elements of the nut screw consist of two rings formed by transversely sectioning the nut screw perpendicular to the worm screw axis, and the two rings are both mounted in axially movable manner, with the spherical-wedge-shaped cam inserted between the adjacent ends of the same and coope
REFERENCES:
patent: 4052906 (1977-10-01), Genini
patent: 4624288 (1986-11-01), Pezzoli
patent: 5320143 (1994-06-01), Hwang et al.
Falik Andy
Intrapatent Limited
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