Textiles: weaving – Pile tufting
Reexamination Certificate
2000-06-22
2001-09-25
Falik, Andy (Department: 3741)
Textiles: weaving
Pile tufting
C139S00700A, C139S021000, C139S455000
Reexamination Certificate
active
06293314
ABSTRACT:
The invention relates to a method and a device for selecting pile yarns in gripper Axminster weaving machines, more specifically in carpet weaving machines of the gripper Axminster type. With such weaving machines the pile yarns of different colors are placed next to each other in a line in pile yarn cariers, which are moved in a lengthways direction under control of an electronic jacquard device through movement according to the pattern, in order to bring the selected color opposite the gripper jaws.
In such carpet weaving machines the pile yarns are held in pile yarn cariers which protrude in a horizontally, obliquely or vertically disposed direction. The pile yarn ends protrude out of the pile yarn cariers sufficiently on one side in order to be taken along by gripper jaws. The gripper jaws are rotatably disposed in order to grip the protruding yarn ends in an upwardly rotating movement and in order to bring these downward, so that they can be woven into the backing fabric of the carpet.
From the British patent publication GB 2 231 590 such a device is known for selecting pile yarns in gripper Axminster weaving machines. In this device a hinged extension piece of the pile yarn cariers is placed with a protrusion in a certain notch on the lifting beam through the action of an electro-plunger magnet.
A first disadvantage of this device is, that this can only work when the pile yarn cariers are disposed vertically or obliquely up to an angle of max. 45° to the vertical. Gripper Axminster weaving machines with horizontally disposed pile yarn cariers can weave considerably faster because of the fact that the angle of rotation of the pile grippers is considerably smaller.
A second disadvantage is that the pile yarn cariers must be provided of a return device with lingots or return springs in order to hold the protrusion of the rotatable part of the pile yarn cariers in the notch of the lifting beam. This is particularly necessary in order to bring the selected pile yarn into a line for the gripper jaws. These lingots or return springs considerably load the drive of the lifting beam. The jacquard drive therefore limits the weaving speed of a gripper Axminster weaving machine.
At higher weaving speeds the inertia of the pile yarn cariers poses an additional problem. At the end of the travel of the selection movement the selection is completed, but the pile yarn cariers do not immediately come to a standstill through effect of the force of inertia. Through the clearance which is present between the protrusion and the notch on the lifting beam, the pile yarn cariers with the selected pile yarns do not come to lie properly in a line. This causes wear and tear on the protrusion and after a time the protrusion can jump out of the selected notch through which a fault occurs in the selection.
Patent publication GB 2 286 601 shows a pile yarn selection device with horizontally disposed pile yarn cariers. This arrangement is favorable for reaching a higher weaving speed. In practice that higher weaving speed is not sufficiently reached. The forces of inertia on the pile yarn carier at the end of the selection movement are the cause of selection faults: the pile yarn cariers slide through under the selection leaf spring as with a ratchet. The leaf spring is not capable of positioning the pile yarn carier through which faults occur in the selection and the selected pile yarns are not presented in a line. This problem can only be remedied to a limited degree by applying a greater spring pre-tensioning in the spring return device. The drive must then indeed provide a much greater drawing power to the springs and the selection leaf spring has limited load bearing capacity due to buckling.
This device also limits the weaving speed of a gripper Axminster weaving machine.
SUMMARY
The purpose of the invention is to develop a jacquard device or pile yarn positioning system for gripper Axminster weaving machines which is suitable for high weaving speed and whereby no return spring device is necessary.
By pile yarn selection system in this context is understood both a method and a device for selecting pile yarn.
In order to achieve the above mentioned purpose the invention provides a pile yarn selection system for gripper Axminster weaving machines, whereby each gripper is associated with an elongated pile yarn carrier, provided in order to position a number of yarn ends at mutual distance according to the length of that carrier, whereby each pile yarn carrier is axially movable according to its length in order to present a selected yarn to an associated gripper, and whereby a movable selection beam effects the axial movement of the pile yarn cariers, coordinated with the movement of the grippers, by means of protrusions and notches working together on the pile yarn carriers and on the selection beam, while the engagement into each other of the aforesaid protrusions and notches can be selectively controlled in function of the yarn to be selected, in which:
the pile yarn carriers are predominantly horizontally disposed,
the selection beam positively drives the pile yarn carriers in horizontal direction both in forward and in return movement,
and the pile yarn carriers comprise a position of rest into which they can be brought and/or held by a vertical movement of the selection beam.
According to an additional characteristic of the invention the pile yarn carriers are, preferably, provided next to one another on a supporting table and each provided with a hinged arm each of which can be brought by means of a selectively activatable push mechanism into a position, protruding in one direction, whereby protrusions and notches on the arms and the selection beam can engage in each other, and in the supporting table one or more recesses are provided into which a part of the aforesaid hinged arm protruding in opposite direction can fit in position of rest.
According to the invention each arm can furthermore very suitably be provided with a tooth with which all pile yarn carriers are taken back to the position of rest by the selection beam, on its return movement.
According to another more specific preferred characteristic of the invention the aforesaid means which can be selectively activated in order to make the aforesaid protrusions and notches engage in each other consist namely of electro-plunger magnets.
Upon reaching their position of rest the hinged arms of the pile yarn carriers are preferably brought and/or held in the recess in the supporting table by vertical movement of the selection beam, and therefore by a positive action of that selection beam.
According to the preferred embodiment of the invention the pile yarn carriers of the selection system can each be provided with a hinged rack, which is equipped with a number of tooth spaces corresponding to the number of yarn positions in each reed opening of the selection system, intended to work together selectively with a protruding tooth on the selection beam, with its forward movement, whereby the hinged rack is furthermore provided with one more protruding tooth with which the pile yarn carriers with the return movement of the selection beam are brought back to the position of rest.
More specifically the horizontal pile yarn carriers, disposed next to one another on a supporting table, can each be provided with an in vertical direction hinged arm which is provided with tooth spaces on its upper side and which can be brought by means of a selectively activatable electro-plunger magnet or electro-pneumatic plunger into a position protruding upward whereby a tooth protruding downward on the selection beam can selectively engage in a tooth space on the top of the hinged arm, while each hinged arm is also provided with a tooth protruding upward with which all pile yarn holders are taken back by the selection beam, with its return movement to the position of rest, and one or more recesses can be provided in the supporting table into which a part of the hinged arms protruding downward can fit in position of rest.
According to this preferred form of the in
Creighton Wray James
Falik Andy
N.V. Michel Van de Wiele
Narasimhan Meera P.
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