Patent GB-1147277-A (GB)
Title: Wire-wrapping tool
IPC: H01R43/033
Filed: 1967-10-27
Abstract: 1,147,277. Wire-wrapping tools. GARDNERDENVER CO. 27 Oct., 1967 [16 March 1967], No. 48891/67. Heading B3E. A rotary tool comprises a tool casing, and a motor carried by the casing which provides driving rotation when energized and inertial rotation when de-energized; a rotary spindle journalled by the casing and drivably connected to the motor and means operable following deenergization of the motor for arresting inertial rotation of the motor and spindle, said means including a non-rotatable stop member connected with the casing, and a rotatable stop member yieldably connected with the spindle, the stop members being engageable to arrest rotation of the motor and spindle and the yieldable connection between stop member and the spindle including a resilient member for absorbing inertia force produced by the arrest of the motor and spindle. The tool comprises a casing 21 and an integral handle 22 containing inlet and outlet ducts 37 and 38 respectively and a triggeroperated valve 40 which controls the flow of compressed air to a sliding-vane motor 23 at the rear of the casing. The motor shaft 33 drives a planetary speed reducing gear 35 which in turn drives the squared rear end 48 of a spindle 36, which is supported by bearings 46 and 47. The front end of the spindle has a central bore 52 and the whole spindle is inside a housing 49, the rear end of which abuts a retainer ring 58 and the front end of which projects through a nose piece 27. The nose piece is screwed into the casing 21 and clamps a flange 59 on the housing 49, thus locking it against angular movement. A sleeve 63 is clamped in the housing 49 by a collet nut 62 and journals the shaft of a wire wrapping bit 56. A sleeve 57 is pressed on to the front end of the spindle 36, which is notched at 54, and provides a drive for the tang end 55 of the bit shaft. An annular piston 68 is axially slidable in the housing 49, but is prevented from rotating by a lug 77 which enters a slot 110 in the housing wall. The piston is biased rearwardly by a spring 74. The spindle 36 rotates freely in the bore of the piston and has splines over its rear portion, on which slides a drive block 93 which is biased fowardly by a spring 97. The front end face of the drive block 93 has two diametrically opposite flat sloping surfaces which correspond with similar surfaces formed in the rear end of an index cam 80. This cam is freely rotatable on the shaft 36 and its forward end face is spirally shaped as shown at 83 in Fig. 5. The rear end face of the piston 68 has a correspondingly shaped spiral face 75 which terminates in the side face 90 of the lug 77. Operation.-When the valve 40 is opened air passes into the casing 21 through a port 43 and hence into the motor through an opening 34. The air also acts on the piston 68 moving it forwardly against the spring 74 so that the spiral surfaces 75 and 83 are disengaged. A circlip 53 prevents the cam 80 following the piston. At the end of the wire wrapping operation the trigger is released and air is exhausted from the casing, the motor and spindle continuing to rotate due to inertia. The spring 74 moves the piston 68 rearwardly, the spiral surfaces engage and within one turn the side face 90 of the lug 77 is engaged by the radial face 89 on the cam 80. The cam is being driven at this time by the engagement of the sloping flat faces on the drive block 93 with those on the cam. In order to prevent damage to the tool, when the cam 80 suddenly stops, the remaining inertia of the rotating parts is stored in the spring 97 when the drive block 93 moves rearwardly due to relative rotation between the drive block and the cam 80. The bit of the tool has a notch into which the wire to be wrapped is inserted. The arrangement described above ensures that this notch always stops in the same angular position, this position being adjustable by loosening the nose cap 27 and turning the spindle housing 49. In a modification the bit retracts against spring pressure as the wrapping is formed to prevent a turn overlying a preceding turn. An extension connected to the bit shaft slides in the bore 52 in the spindle 36 and is forwardly biased by a compression spring which abuts the closed end of the bore.