Patent GB-190314661-A (GB)
Title: Improvements in Variable Speed and Reversing Gear.
Inventor: NEWMAN WILLIAM HENRY
Filed: 1903-07-01
Granted: 1903-11-05
Abstract: 14,661. Newman, W. H. July 1. Eccentrics.-Relates to variable - t h row eccentrics used in variable - speed and reversing gear of the t y p e described in Specification No. 6326, A.D. 1899, [Abridgment Class Mechanism &c.], for motor cars and for other uses. Fig. 7 shows the arrangement of the gearing for motor cars &c., when a fixed case C, C' is used. The shaft A is driven at a constant speed, and carries at its end a rectangular plate A<3> upon which the eccentric E slides. A counterweight A<4> fixed to the plate balances the eccentric when it has half its maximum throw. To vary the throw of the eccentric, a spindle A<5> sliding in the shaft A carries a wedge A<6> working in inclined slots E<1> in the eccentric. The spindle is moved in or out to vary the throw by means of mechanism actuated from the shaft A and consisting of a cottar A<7> fixed to the spindle and passing through slots in the hollow shaft A ; the ends of the cottar engage the piece G which carries studs G<1> bearing pinions G<2>. A cone-clutch wheel G<3> surrounds the pinions and has internal teeth engaging them, and is screwed upon a piece G<4> which engages a screw thread on the shaft A, and surrounds a projection on the piece G, so that it can rotate around the piece G but carries the piece with it when the screw moves within the piece G<4>. The pinions G<2> engage a wheel G<5> which is loose on the shaft A and is screwed into the clutch wheel G<6>. The clutches are surrounded by a double-cone clutch G', G<8> which can slide but cannot rotate in the case, being operated by means of a rack on the clutch engaging a pinion in the case. The clutch G<8> is arranged to screw into the clutch G<7>. In operation, when the parts are in the position shown, they all rotate as one piece with the shaft A ; by moving the mechanism in the direction of the arrow, the clutch G<7> prevents rotation of the clutch G<3> and the piece G<4>, and the piece G with the remainder of the mechanism moves bodily along the shaft and reduces the throw of the eccentric to zero. By moving the sliding clutch in the opposite direction, the clutch G<6> and wheel G<5> are held still. The pinions G<2> then travel around the wheel G<5> and drive the wheel G<3> quicker than the shaft A, thus moving the piece G along the shaft and increasing the throw of the eccentric. Stops are provided to prevent the sliding clutches from moving beyond the points which produce maximum and minimum throw. The eccentric E is surrounded by arms F working on pins D' fixed to the clutches D, which oscillate on pins D<3> and are surrounded by gear rings D<3> gearing with a central pinion B on the variablespeed shaft B'. An alternative method of constructing the variable eccentric is shown in Fig. 25. The constant-speed shaft A is surrounded by a sleeve B provided with an eccentric B<1> of half the total required eccentricity ; the disc B<1> fits a recessed flange in the eccentric E, which is placed eccentrically on the flange relatively to the recess, an amount equal to half the total required eccentricity, so that, by turning the eccentric E on the disc B', the eccentricity may be varied from zero to the maximum. The turning is accomplished by means of an arm A' working in a slot in the eccentric E, so that relative motion of the shaft A and sleeve B is required to vary the eccentricity. The gearing necessary for producing this relative motion consists of a wheel A<2> on the shaft, and a wheel B<3> on the sleeve having different numbers of teeth. Pinions C, C<1> on studs D gear with the wheels, and wheels C<2> formed with the pinions C' gear with a wheel F free on the shaft A. The piece D carrying the studs D' surrounds a sleeve F<1> on the wheel F and has a recess in which the brake G works. The brake may be caused to grip the piece D or the sleeve F<1>, or may be in a midposition as shown, the whole mechanism then rotating with the shaft. By applying the brake to the piece D, the wheels A<2>, B<3> are driven at different speeds and the eccentricity is reduced, while, by braking the sleeve F<1>, the eccentricity is increased. Stops are provided to limit the variation of the eccentricity. The eccentrics are balanced by means of weights E<4>, B<2>. In a modified arrangement, the arm A' and slot are replaced by a pinion on the shaft engaging internal teeth on the eccentric E. In another form of variable crank, the pin is forced towards the centre to reduce the throw by means of spiral springs, and is forced outwards to increase the throw by means of wedges operated by means of a handle and other mechanism, or the wedges may be operated by means of gear-wheels, eccentrics, and links connected to a ring and sleeve on the wedge spindle. For transmitting large powers, the variable eccentric is provided with a second bearing supported by the case, and the number of clutch wheels may be increased, by making the central pinion sufficiently broad to gear with two clutch wheels placed side by side, or the clutches may be kept separate from the gear-wheels and connected by short links to the variable eccentric, one clutch being connected directly thereto. In another form for small powers, shown diagrammatically in Fig. 35, the variable eccentric E is connected by arms F to the clutch levers D, which, by means of ratchet or other mechanism, operate the case C. A silent ratchet may replace the ordinary ratchet shown, or gripping-blocks may be actuated from the eccentric to grip the ring C, or the gripping-blocks may be toothed to gear with toothed sectors working on fixed centres and actuated by means of levers from the eccentric. In variable eccentrics of the type in which the inner spindle is rotated relatively to the outer sleeve, a spring connection is provided between the spindle and sleeve, any increase in the tension of the spring reducing the throw of the eccentric.