Patent GB-344879-A (GB)
Title: Improvements in or connected with tuft gripper mechanism of looms for weaving tufted pile fabrics
IPC: D03D39/02
Filed: 1929-11-11
Abstract: 344,879. Pile -fabric looms. HUTCHINSON, HOLLINGWORTH & CO., Ltd., WOOD, A. E., and LOWE, W. V., Loom Works, Dobcross, Yorkshire. Nov. 11, 1929, No. 34306. [Class 142 (ii).] Forming tufts around wefts.-In tuft gripping mechanism for conveying yarn from a supply to the fell of the fabric for incorporation therein, a constantly rotating cam, coaxial with the gripper shaft, is adapted to operate the movable members of the grippers, means also being provided for balancing the torque on the gripper shaft and for enabling said shaft to be disconnected from the rest of the cam drive. The grippers are of the usual form and comprise a fixed member 201, Fig. 1, and a movable member 20<2>, the latter being provided with a forked tail-piece 20<4> to straddle a blade 116 on a shaft 113, whilst the opening and closing means comprise a constantly rotating gear wheel 103, loosely mounted on the gripper shaft 19 and driven, by means of a chain 98 and gears 100, 102, from the lay cam shaft. A cam 104, fast on the wheel 103, acts on a bowl 105 carried by an arm 106 pivoted at 107 to a boss 108 fast on the gripper shaft, the arm 106 acting through a spring 109, rod 110, and arm 111 to rock the shaft 113. The grippers are open when they are moved to the top position, but contact of the cam 104 with the bowl 105 causes them to close and grip the yarn, and in their subsequent downward movement, since the gripper shaft rotates in the same direction of the gear 103, the bowl 105 rides on the surface of the cam 104 and keeps the grippers closed. When the limit of this movement is reached, however, the continued rotation of the gear 103 causes the cam 104 to ride from beneath the bowl 105 and permits the arm 106 to move pivotally under the action of a spring 1091 to release the yarn. The gripper shaft 19, Fig. 3, is driven from the bottom shaft 18 of the loom by means of a toothed segment or guadrant 48 connected by an adjustable link 51 to a pivotally mounted lever arm 52, which may be connected at will, by pin and slot means, to a constantly moving segment 53 operated by a cam 55 on the low shaft 18. Associated with the cam 55 and set in diametrically opposite position is a second cam 55<1> which acts on a dummy segment 53<1>, both segments being connected by means of a chain or flexible member which passes about a guide pulley 57, the effect of which is to maintain the bowl or runner 54 of the operative segment 53 in constant contact with the surface of its cam 55. To balance the torque on the gripper shaft as the grippers move up and down, an arm 61, Fig. 6, fixedly mounted on the shaft 19 is connected by a link 60 to one end of a lever 59 pivoted on a stud 59<1> and carrying at its other end a slidably mounted weight 58. A crank 62, rotatable on the stud 591 by means of a chain 63 and segment gears 641 from the bottom shaft 18, is connected by links 65 and 66 to the weight 58. As the gripper shaft rotates to carry the grippers upwardly or downwardly, the action of the crank 62 causes the weight 58 to be moved outwardly from the full line or broken line position along the lever 59 so that by the time the grippers are substantially horizontal and are exerting the maximum torsion on the shaft, the weight occupies the position indicated in dotted lines and exerts a maximum counterbalance.