Patent GB-128034-A (GB)
Title: Improvements in and relating to Resilient Couplings for the Transmission of Power by Shafting.
Inventor: ALEXANDER FRANCIS HERBERT
IPC: F16D3/80
Filed: 1918-07-05
Abstract: 128,034. Alexander, F. H. July 5, 1918. Clutches, claw.-To prevent shocks in dog clutches, one of the clutch members is formed in two relatively rotatable parts separated by pneumatic means. In the iorm shown in Fig. 3, the male or female clutch member is formed in two parts, one S secured to the shaft and provided with a stop 2 and the other R loose and carrying a stop 4, air, steam, or other elastic fluid under pressure being supplied to the chamber 3 between the stops by pipes 6 or 7, according to the direction of drive. If the direction of drive is reversed, it is necessary to return the stop 4 to the opposite side of the stop 2 before the new drive begins. This is accomplished by opening one pipe 6 or 7 to the atmosphere and supplying compressed air through the other. To prevent violent contact between the stops 2, 4 during this operation, the pipes 6, 7 are provided with valves 10 adapted to close the pipes under the control of compressed air admitted through auxiliary pipes 6<11>, 7<11>, so that, when the stop 4 reaches the point shown in its clockwise movement towards the stop 2, the pipe 6, which has hitherto been open to the atmosphere, is closed and air trapped between the stops forms a check to the velocity of the stop 4. To prevent chattering during drive, spring catches 14, Fig. 5, may be used to lock the parts in their positive driving positions, channels 16, 17 being provided for the passage of compressed air to unlock the parts when desired. The stop 2, Fig. 8, engages a helical slot 3" in the member S, which is splined to the shaft 1, compressed air being supplied continuously through a flexible or telescopic pipe b to one end of the slot as the part S slides along the shaft. A valve allowing slow escape of air is arranged near the driving end of the slot so that, when it is passed by the stop 2, trapped air prevents shock. Where drive in both directions is to be provided for, a second system supplying the opposite end of the slot is required. 13y the provision of elongated ports in the shaft 1 or member S, the pipe b may be dispensed with. In the form shown in Figs. 10 and 13, and, if desired, in any other of the forms described, air at atmospheric pressure is the cushion medium. The part R, Figs. 10 and 13, carries fixed cylinders 250 within which work pistons 2<1> on rods 24 carried on blocks 28 sliding radially in slots in the member S. Non-return valves 23 in the cylinders permit the entry of atmospheric air. Springs 18<1> or springs acting directly on the rods 24 restore the pistons 2' normally to central position. As, in taking up the drive, the pistons 2<1> reach the cylinder ends, spring-pressed locking- bolts 33 engage the ends of the lugs 37 and lock the drive. The bolts 33 are controlled by levers 35 linked to a collar 36 which is so interconnected with the gear operating the dog clutch that clutch and bolts are disengaged together. The clutch may be of the combined friction and positive type described in Specification 132,775. Two or more stops 2 and chambers 3 may be employed.