GB563534A - Improvements in dynamometers - Google Patents

Abstract

563,534. Absorption dynamometers. GARRETT, F. A. Jan. 14, 1943, No. 731. [Class 106 (ii)] A dynamometer of the prony brake type bas two levers 7, 8 which are fulcrumed together, are connected at one side of the fulcra 18, to brake shoes 3, 4 on a brake drum 1, and have resilient means for applying load to them at the other side of the fulcra so as to apply the brake shoes to the drum, the brake shoes having adjustable abutments 12, 15 for engagement with the levers so that the levers act alternatively as brake levers or secondary levers according to the direction of rotation of the drum and actuate reaction means adapted to indicate the torque load. In the embodiment shown in Fig. 1, a screw 23 is adjusted until the brake shoes are applied to the drum, and screws 12, 15 are set slightly clear of the levers 7, 8. According to the sense of rotation of the drum, one or other of the screws 12,15 engages its corresponding lever which drives the other lever into contact with the torque indicator 26 or 27. Momentary variations of the load are absorbed by a spring 21. In Fig. 2, the spring 21 is replaced by a pair of hydraulic cylinders 30 connected to a loading cylinder and a pressure gauge. The force of the brake lever is absorbed by one or other of two hydraulic cylinders 59, 60, connected together to a loading cylinder and to a pressure gauge which indicates the torque. The levers 7, 8 and the brake shoes are counterbalanced by weights 86, 87. The pressure in the hydraulic cylinders can be released by a manually operated ball valve connecting the loading cylinders with a reservoir. In Fig. 8, the cylinders 59, 60 are replaced by a single cylinder 101, movement of the levers 7, 8 being transmitted through a cable 113 to one or other of two bell-cranks 109, 110 adjustable by screws 122, 123 on a lever 107 centrally pivoted to the plunger 104. The lever 107 turns about one or other of two rollers 124, 125 abutting against the frame, to transmit pressure to the cylinder 103. The brake drum, Fig. 7, is hollow and receives cooling water from a pipe 81, the water escaping through a trough 82.