Patent GB-1024129-A (GB)
Title: A tool having a mechanism for restoring a work engaging member to a starting position at the conclusion of an operation
IPC: H01R43/033
Filed: 1964-01-21
Abstract: 1,024,129. Wire wrapping tools; screwing up tools. THOR POWER TOOL CO. Jan. 21, 1964 [Jan. 24, 1963], No. 2549/64. Headings B3E and B3N. A wire wrapping tool, screwdriver or nut setter comprises a housing, a work engaging member movably mounted on the housing and having a starting position and indexing means for urging the member towards the starting position, the indexing means comprising a first magnet operably engaged with said member for movement therewith, and a stationary second magnet mounted in fixed position relative to said first magnet, the magnetic poles of the magnets being arranged such that the magnetic fields coact to urge the member into the starting position. The tool comprises a field housing 16 in which is mounted a motor 12, a tool housing 10 supporting a rotatable mandrel 11, a clutch 13, magnetic indexing means 14 and a handle 17 housing a trigger 61 which serves to actuate the motor via a switch 53 and rectifier 52. The forward end of the armature shaft 30 supports a cooling fan 70 and is rotatably mounted in a rotatably mounted spindle 34 having a jaw 79 co-operating with a jaw 78 on the fan 70 to form a lost motion clutch. Each jaw subtends an arc of 35 degrees. The shouldered mandrel 11 is coupled to the spindle 34 by a semi-circular tang 84 engaging a complementary tang 83 secured therein and rotates within a sleeve 86 non-rotatably held by a chuck 87 secured to the housing 37. The forward ends of the mandrel 11 and sleeve 86 are shaped to engage a wire and wrap it around a terminal when the mandrel is rotated relative to the sleeve. A hole 96 in the mandrel locates it about the terminal and an axially extending slot 97 formed in the outer periphery thereof receives the end of the wire to be wrapped. The end of the sleeve is outwardly flared at 98 and a notch 99 formed therein displaced at 90 degrees thereto. In the starting position the slot 97 is preferably in line with the flared portion 98. The indexing means comprises an inner magnet 101 secured to the outer periphery of the spindle 34 and an outer stationary magnet 102 secured to the inner periphery of a sleeve 38. The magnet 101 is polarized so that its magnetic poles are at its outer periphery and on opposite sides thereof and each extends over an arc of 160 degrees. The magnet 102 is similarly polarized with its poles on its inner periphery. The magnets are mounted such that when they are at rest the mandrel is in the start position. The angular position of the sleeve 86 relative to the field housing 16 may be adjusted by loosening a clamp nut 41 and rotating the bearing housing 37 relative to the housing front plate 42. In a modification the clutch comprises an annularly grooved member 156, axially slidable along a splined drive stud 157 and journalled in a sleeve 158, having jaws 182, e.g. three, which engage with jaws 183 on a driver member 180 also journalled in the sleeve and coupled to the spindle 181 which carries an inner indexing magnet 200, and drives the wrapping mandrel assembly. The clutch is driven by the motor via a shaft pinion gear 170 and a ring gear 171 through planet idler gears 172, 173 mounted on a carrier 177 which is rigidly secured to the stud 157. The clutch member 156 is held out of engagement with the member 180 by one end of a pivoted lever 161 engaging the groove therein whilst the other end is pivotally connected to a spring-biased rod 163 in the trigger 149. In operation the trigger initially engages the clutch prior to operating the motor starter switch 146, the spring 164 serving to bias the clutch member into engagement. Upon release the trigger disengages the clutch prior to switching off the motor, the mandrel coming to rest and being reset by the magnets. The indexing means described may be used in power-operated screwdrivers and nut setters. Pneumatic or hydraulic motor drives may replace the electric motor.