GB673592A - Improvements in or relating to engine-starter drives - Google Patents

Abstract

673,592. Turning-gear. BENDIX AVIATION CORPORATION. July 27,1950 [Aug. 8, 1949], No. 18818/50. Class 7(v) In 'an engine starter drive comprising a power shaft 1, a sleeve 4 fixedly mounted thereon having spline grooves at one end and a stop shoulder 6 at the other, a screwshaft 11 having clutch teeth 12 at one end slidably journalled on the intermediate portion of the sleeve 4, a clutch member 9 slidably but non-rotatably mounted on the splined portion of the sleeve 4, an abutment 14 on the sleeve 4 limiting movement of the member 9 away from the sleeve, a spring 13 urging member 9 into driving engagement with the clutch teeth 12 and normally holding the screw-shaft 11 against the stop shoulder 6, a control nut 18 threaded on the screw-shaft 11, a barrel member 21 rigidly mounted at one end on the control nut, a pinion 16 slidably journalled on' the power shaft for longitudinal movement into and out of mesh with a gear 17 on the engine to be started and having a driven coupling member 28 fixed thereon, there is provided a driving coupling member 24 non-rotatably mounted in the other end of the barrel member 21 and yielding means, such as spring discs 31, on the pinion 16 urging the coupling members into driving engagement. The pinion 16 and barrel 21 are normally located in extended relationship by a mesh enforcing spring 34 positioned between a stop in the interior of the barrel and one of the spring discs 31; an anti-drift spring 37 is located between a thimble 38 on the stop shoulder 6 and the nut 18. In operation, the rotation of the power shaft 1 is transmitted through sleeve 4, clutch member 12 to the screw-shaft 11 so that the nut 18 and the associated parts are traversed to the right to mesh the pinion 16 with the engine gear 17 whereupon the nut 18 abuts the shoulder 6 so that the screw-shaft 11 is forced leftward against the compression of spring 13 thereby ensuring firm engagement of the overrunning clutch 9, 12, the clutch member 9 finally contacting the abutment 14; torque is now transmitted,through the coupling members 24, 28 to crank the engine; if, however, the required torque is or should become excessive the coupling members will be forced apart against the bias of the spring discs 31 until the overload ceases. Should tooth abutment occur, the axial movement of the pinion 16 is arrested but the barrel and nut continue to move by virtue of lugs 23 on coupling member 24 travelling in slots 22 in the barrel 21 so that the mesh enforcing spring 34 is compressed until the rotary component of the force transmitted through the screwshaft is sufficient to index the pinion and engine gear, whereupon the spring 34 ensures the initial meshing of the pinion and engine gear.