GB516904A - A new or improved device for screw and bolt driving and nut running - Google Patents

Abstract

516,904. Screwing-up nuts &c. GWATKIN, F. A. S. (Black & Decker Manufacturing Co.). July 28, 1938, No. 22526. [Class 83 (iii)] In a portable, power-driven manually operable tool for driving or running nuts, bolts &c. the tool shaft is driven through an epicyclic gear comprising planetary pinions on a carrier which may be held stationary to drive the tool or may be allowed to rotate to enable the tool to remain stationary, means being provided for adjusting minutely the pressure with which the carrier is held stationary to determine the torque at which slip takes place. In one form the shaft of an electric motor 3 carries a pinion 6 engaging two gears 8, 9, attached to shafts 10, 11 rotatable in a carrier 15 and carrying pinions 19, 20 which engage a gear 21. The boss of the gear 21 is provided with a shank 30 rotatably supported within the tool spindle 32 and carries a transverse key 41 engageable with clutch teeth 40 on the spindle when the tool is pressed against the nut &c. to be tightened, but normally kept apart therefrom by a spring 35. A thrust bearing 28 for the gear 21 is held in the gear casing 1 by a washer 27<1> and screw 27. The motor 3 may operate through reversing gearing for. screwing up or unscrewing and for either operations rotation of the'carrier 15 is prevented by a surrounding sleeve 16 split axially at 45 and contracted on to the carrier by a block 47 having a wedge-shaped groove engaging' axially tapered flanges at the sides of the split 45. The block engages a recess 47<1> in the casing 1 to prevent rotation of the sleeve 16 and may be moved axially, to vary torque at which the carrier may slip when the nut &c. is set, by means of a screw 50 and lock nut 53. When the carrier slips it rotates and allows the pinions to roll round the gear 21 without driving the tool, until the motor is stopped or the clutch 40, 41 disengaged by withdrawing the tool from the nut &c. being operated upon. An extension 22<1> of the shank 30 is rotatably mounted in the carrier. 15 and the motor casing 2 is provided with a pistol-grip handle and a switch. A shroud 37 for the tool spindle and chuck is attached to the bearing bush 36 for the spindle: In a modified construction wherein tangential hammer-blows may be imparted to the tool the carrier 111, Fig. 11, is not split and is prevented from rotating by a pivoted pawl 132 engaging a bevelled recess 131 therein. The pawl is pivoted to the gear casing 101 at 133 and is pressed into contact with the carrier by an adjustable spring 134. When the nut &c. is set the pawl is cammed out of the recess 131 and rotation of the tool is stopped until the carrier has made one revolution and the pawl drops into the recess again, thereby delivering a rotational blow to the tool.