GB555311A - Improvements in or relating to pneumatic braking devices for a rotating element - Google Patents

Abstract

555,311. Brakes. BOBST & FILS, SOC. ANON, J. Oct. 31, 1941, No. 14058. Convention date, Nov. 18, 1940. [Class 103 (i)] In a braking device for a rotating member in which the braking action is produced by the compression of a gas in a cylinder or equivalent, maximum compression is arranged to be effected when the crank and connecting rods by which the piston is operated are at right angle to each other and to permit the continuation of the rotation of the rotating member beyond this position the cylinder or a second piston on which the compression reacts is withdrawn. In Fig. 2, air is compressed in a cylinder 5 by a piston 4 actuated through a crank and connecting rod 6, 2, by the rotating member to be braked. A second piston 8 is actuated, for instance, by a cam in such a manner that maximum compression is effected when the crank and connecting rod are at right angles as shown, the piston 8 being subsequently withdrawn to permit continued rotation of the member 1. Instead of providing the piston 8, the cylinder may be reciprocated. In Fig. 4, the member 1 is rotated by a sector 12 oscillated by the part to be braked through a rod connected at 14, the drive between the sector and members 12, 1 being un-indirectional. The cylinder 5 is pivotally connected at 7 on a crank 17 integral with the sector 12 and may have a permanently open atmosphere adjustable port 18. In the position shown, also the cylinder is freely open to atmosphere through passages 20, 21 in the cylinder and the pivot 7 respectively. There is thus no braking action during the first part of the movement of the sector in the direction of the arrow 16 and during which the piston and cylinder move respectively downwards and upwards. At about the crank position d, the passages 20, 21 are completely out of register and when the crank and piston again reach the positions shown, the cylinder has reached. As uppermost position at which the maximum braking action is this effected. The sector then returns but without, however, turning the crank. The device shown in Fig. 4, may be used in machines for feeding paper or like blanks, for example machines, fitted with conveyer chains carrying gripper bars, the chain s being intermittently stopped.