Patent GB-176371-A (GB)
Title: Improvements in or relating to electro-mechanical driving apparatus for vehicles
IPC: B61C9/38
Filed: 1922-03-02
Abstract: 176,371. Kurz, O. March 2, 1921, [Convention date]. Operating clutches. - Motor vehicles, particularly those used in trackless traction, are driven from shunt-wound motors, preferably of the polyphase type having squirrel-cage armatures, through a friction clutch in which the spring pressure is automatically adjusted with the load and, if desired, through a variable-speed gear, which is employed to maintain the load on the motor approximately constant, the motor rotating throughout at approximately constant speed. The motor 16, Fig. 7, drives a shaft 8 carrying a sleeve 9 provided with a camsurface 18 engaging through balls 20 a corresponding surface 19 on a drum 10 secured to a sliding shaft x driving a shaft 13 through a friction clutch 11, 12. The shaft 13 drives the roadwheel 17 directly or through a variable-speed gear. The clutch is normallv engaged by a spring 14, the pressure of which is reduced by sliding of the shaft x produced by the cams 18, 19, or by the clutch pedal 15. When the clutch pedal is released, the clutch is fully engaged, but owing to the velocity of the constant-speed shaft 8 effects a slipping drive only. As the vehicle speeds up, the relative velocity of the members of the clutch 11, 12 is reduced and the co-efficient of friction increases accordingly. The effect of this increase of friction is reduced and gradual take-up of the drive is ensured by compression of the spring 14, produced by the action of the cams 18, 19 as the load increases. Fig. 8 shows a modified clutch in which the slip is divided equally between two similar clutches 11, 12 and 11<1>, 12<1>. The two clutch shafts 21, 21<1> are connected to turn together by a sliding coupling 22 and carry to rotate therewith a radial spindle 27 on which rotates a bevel wheel 26 gearing with wheels 24, 25 on the driving and driven shafts 8, 13; the velocity of the shafts 21, 21' is thus midway between those of the shafts 8, 13. The spring 23 bearing against the shafts 21, 21<1> effects clutch engagement. The shaft 13 preferably drives the road-wheels through the intermediary of the speed gear shown in Fig. 9, in which alined shafts 13, 35 carry rigidly spur-wheels 28, 39 and loosely a spur-wheel 33, and aligned lay shafts 31, 36 carry rigidly wheels 30, 40 and loosely a wheel 34. Clutch members on the wheels 33, 34 may be engaged in pairs by clutch members splined on the main and lay shafts under the influence of levers 45, 46, giving four speeds, of which the third is direct between the shafts 13, 35. The drive is conveyed from the wheel 39 to the driving-wheel 41 of the differential on the rear axle, or the wheels 39, 40 may both be geared to the wheel 41 if they no longer mesh together and the wheels 28, 30 and 33, 34 are connected by chain gearing. The speed gear is controlled by the mechanism shown in Figs. 10, 11, and 13. The control lever 54, 59 may be rocked in two directions at right-angles to rotate bevel-wheels 60, 64 which are geared to wheels 60', 63 on tubular shafts 61, 62, which may be connected directly to the clutch levers 45, 46 or may carry arms or forked levers 61<1>, 62<1> bearing on or connected by pin-and-slot connections to levers 52<1> on shafts 52, 53 to which the levers 45, 46 are secured. The shafts 61, 62 are torsionally elastic, so that the control lever 54 may be operated at any time and the clutch operation will follow when conditions permit. In a modification, the elasticity is provided by the use of plate springs to replace the levers 61<1>, 62'. Arms 69, 70 on the shafts 52, 53 are arranged to co-operate with arms 67, 68 on a shaft 66 operated by the clutch pedal 65 that when the lever 54 has been set for a change of speed, the gear cannot be changed until the clutch has been disengaged, and, further, if the gear is not then properly engaged, the clutch cannot be re-engaged. By providing the arms 67, 68 with central recesses, however, the clutch may be operated when the gears are in neutral position. The shaft 66 may be operated independently of the clutch. As shown in Fig. 13, themechanism is arranged on the vehicle with the motor 16 central, the slipping-clutch 11, 12 beneath one longitudinal girder 47 of the vehicle, the driven shaft 13 passing through the motor and driving the speed gear 49 beneath the other girder 47. This arrangement renders the slipping clutch and the speed gear readily accessible. The Specification as open to inspection under Sect. 91 (3) (a) comprises also the following additional matter :-The control lever 54, Fig. 13 (Cancelled), may carry a spring-pressed rod 71 and roller 74 engaging in notches in two rods 75 connected respectively by rack and pinion gearing to the shafts 52, 53 so that when the lever 54 is operated a knob 72 on the end of the rod 71 is lifted and only returns when the speed-gear clutches have been thrown fully over, thus affording an indication to the driver that the gear has been changed. In its raised position, the rod 71 may engage a quadrant, so that the lever 54 is locked until the gear has been changed. This subject-matter does not appear in the Specification as accepted.