Patent GB-1283471-A (GB)
Title: Improvements in impulse motor
IPC: F16D31/06
Filed: 1970-02-23
Abstract: 1283471 Impulse generating device ATLAS COPCO AB 23 Feb 1970 [28 Feb 1969] 8545/70 Heading B3N An impulse generating device, normally in a nut-runner, comprises a cylinder 15<SP>1</SP>, an anvil 21, a sealing rotor 28 and a relief valve 35, the cylinder has end cover-pieces 16, 17 and the cavity 43 between the anvil and cylinder is filled with a liquid, said sealing member and anvil at a predetermined position in cavity 43 define a chamber as a part of said cavity of decreasing liquid volume, said relief valve is for relieving and closing said chamber relative to the remainder of said cavity, and there are means for controlling the relief valve in dependence upon the rotation of said cylinder for moving during subsequent passages of the sealing member past a sealing position firstly at least once in sequence said relief valve to a relief position, whereby said chamber is kept relieved and for thereafter moving said relief valve to a closed position during a subsequent passage of said sealing member past a sealing position, whereby a pressure impulse is produced in said chamber to rotate said anvil. Cover 17 has a main drive gear 39 which is geared to the rotor 28 by gears 41, 42 in a 2:1 ratio. In operation, a socket wrench is fitted to end portions 25, an outer housing 38 is held stationary by a suitable handle and cover 17 is driven by a motor (not shown). Friction in the device drives the anvil till resistance to movement causes the anvil to stall. Then the cylinder and rotor rotate until a sealing position as shown in Fig. 4b is reached. Pressure build up in chamber 43<SP>1</SP>, due to further rotation of the cylinder, is prevented by relief valve 35 being forced open. A further rotation of the cylinder produces the sealing position of Fig. 4d. Here valve 35 is closed and there is a pressure build up in chamber 43<SP>1</SP> to produce an impulse on the anvil by the action of liquid pressure on the rotor 28. The maximum value of said pressure impulse is adjustable by a ball valve 47. The valve connects the two chambers 43<SP>1</SP> and 43<SP>11</SP> via bores 46, 51 in the anvil. The device can be driven in the reverse direction. In a modification, Fig. 8d, the sealing rotor 54 is partly cylindrical and the relief valve 58 is journalled centrally in the anvil. The rotor and the relief valve are driven via suitable gearing and controlled by rotation of the cylinder. In Fig. 11c, the construction is similar to that of the first embodiment except that the relief valve takes a different form and is journalled in the anvil as shown by numeral 69; also the gearing to drive the rotor and relief valve so that an impulse is produced every third revolution of the cylinder instead of every second revolution as previously. In Fig. 13b, the sealing rotor takes the form of a vane 73 slidingly mounted in the anvil 21. The gearing to drive the relief valve 76 could be such as to produce an impulse every 2 or every 4 revolutions of the cylinder. Instead of being used in a nut-runner the pressure impulses may be led from the chamber hydraulically to an impact or vibration motor.