Patent GB-652816-A (GB)
Title: Improvements relating to dobbies for looms
IPC: D03C1/06
Filed: 1948-09-14
Abstract: 652,816. Dobby. SULZER FRERES SOC. ANON. Sept. 14, 1948, No. 24064. Convention date, Sept. 20, 1947. [Class 142 (i)] A single lift open shed dobby includes two lifting blades 30, 31, traversing arcuate paths, and pairs of lifting hooks 9, 10, pivoted to cams 7 and guided by links 11, 12 so that their movements conform to the paths of the lifting blades. Heald actuating jacks 3 engage the cams by means of followers 5, 6 which rest on concentric portions of the cams when the latter are in their extreme positions, so that forces on the jacks cannot turn the cams. The lifting blades are actuated by cranks which move them from left to right to form the shed for one pick and from right to left for the next pick. Each pair of lifting hooks 9, 10 is set by a lever 13 coupled to a control hook 15 actuated by cam-operated control blades 55, 56 in accordance with a pattern card; a spring-loaded latch 16 holds the lever 13 in either of its positions. The pattern cylinder 77 is rotated intermittently by a worm having zero pitch for most of its circumference. Before each movement of the cylinder, reading needles 25 are lifted clear of the pattern card by raising a bar 86 and also raising a shaft 23 carrying bell crank levers 22 which couple needles to the hooks 15. Operation. As shown in Fig. 1, the control hook 15 has been moved to the right into engagement with the control blade 55, which now makes a downward oscillation, taking the hook 15 with it and thereby raising the lifting hook 9 off the lifting blade 30, and raising the lifting hook 10 into the path of the lifting blade 31; the control blade 55 returns to the mid-position shown without affecting the hook 15 (the mouth of which is wider than the blades). The lifting blades 30, 31 then move to the right without turning the cam 7, so that the jack 3 remains in the left-hand position shown; during the movement of the lifting blades, the lower blade 31 encounters an edge 115 of the hook 10, thereby depressing the hook; all the parts then occupy the positions shown in Fig. 1 ,except that the lifting blades 30, 31 are in the positions shown in chain line. If, on the other hand, there had been no perforation in the pattern card, the control hook 15 would have been swung to the left into engagement with the control blade 56; the upward oscillation of the blade 56 would not have moved the hook 15 (owing to the width of its mouth), and the cam 7, and consequently the jack 3, would have been turned clockwise due to the engagement of the lifting hook 9 with the lifting blade 30. Before the lifting blades 30, 31 return to the left, the control blades again oscillate, the blade 55 upwardly and the blade 56 downwardly. With the lifting blades in the chain line position and the other parts as in Fig. 1, this oscillation of the control blades leaves the parts unaffected so that, when the lifting blades move to the left, the jack 3 remains in the position shown; but near the end of its stroke, the lifting blade'30 rides on the edge 116 of the lifting hook 9, thereby raising both hooks 9, 10 and lowering the control hook 15. On the other hand, if there had been no perforation in the pattern card, the control hook 15 would have been depressed by the control blade 56; the lifting hook 10 would then have been engaged with the lifting blade 31, whereby the jack 3 would be turned anticlockwise. Swiss Specification 211,474 is referred to.