Patent GB-940981-A (GB)
IPC: D01H5/56
Filed: 1959-11-17
Abstract: 940,981. Drafting apparatus. SKF KUGELLAGERFABRIKEN G.m.b.H. Nov. 17, 1959 [Nov. 22, 1958], No. 38985/59. Heading D1D. A toprollcarrying arm for drafting- apparatus pivotable between a working position and an upper inoperative position and having weighting- means which produce a reaction on the arm tending to move it towards the upper inoperative position, is held in working-position by latching-means which can be released by downwardly pivoting the arm and then allowing it to pivot upwardly past its working position under said reaction, the arrangement being such that the arm can be relatched by depressing it from the position it then assumes and releasing it, without the necessity of further raising the arm towards the upper inoperative position. As shown, the latching-means comprises a latch 9 and a catch 10, Fig. 4. The latch is of U-form with limbs pivoted at 18 to the arm 1 and an upper bridge part 9<1> lying between the limbs 15<1>, 15<11> of a coil spring carried by the arm. The catch is pivoted at 13 to a bracket carried by a support 8 to which the arm is pivoted at 5, a plate-spring 14 serving to retain the catch 'in various positions to which it is moved. The catch has a curved head providing under-surfaces 10<1>, 10<11> co-operating respectively with the bridge 9<1> and a surface 12<11> on a stop 12 carried by the arm. The stop has a further surface 12<1> co-operating with the side of the catch. When latched in working position, Fig. 1, the surfaces 9<1>, 10<1> are in contact with limb 15<11> in tension, and the catch on contact with surface 12<1>, surfaces 10<11> and 12<11> being slightly out of contact. To release the latching means, the arm is depressed and then released. when the arm is depressed, surfaces 9<1>, 10<11> are separated so that limb 15<11> is able to rotate the latch 9 anti-clockwise to a position when the spring is untensioned (Fig. 2 not shown). When the arm is released, the reaction of the weighting- means causes the arm to rise so that stop 12 parts the catch anti-clockwise into contact with bridge 9<1> and so pivots the latch anti-clockwise to tension limb 15<1>, Fig. 3. If it is now desired to relatch the arm in working position, the arm is again depressed and released. When the arm is depressed, limb 15<1> being under tension forces the bridge 9<1> under surface 10<1>. When the arm is released it rises and the movement of the arm rotates the latch and consequently the catch clockwise and the parts assume the positions shown in Fig. 1. If it is desired to raise the arm from the position shown in Fig. 3 to the upper, inoperative position, the bridge 9<1> can ride over the head of the catch the spring-limbs becoming untensioned. To now relatch the arm, it is depressed past working position and then released. When the arm is depressed, the bridge 9<1> strikes the lower curved part of the head, is rotated anti-clockwise and tensions limb 15<1> so that when the bridge clears the head it is moved below surface 10'. When the arm is released, the arm rises; surfaces 9<1>, 10<1> being in contact, the catch and latch are rotated clockwise so that the latch is brought against stop 12 and limb 15<11> is tensioned as in Fig. 1.