Patent GB-402407-A (GB)
Title: Improvements relating to variable speed power transmission mechanism
Filed: 1932-02-19
Abstract: 402,407. Variable-speed gearing; controlling motor vehicles. HAYES, F. A., Middletown, New Jersey, U.S.A. Feb. 19, 1932, No. 4981. [Class 80 (ii).] There is combined upon a vehicle in series with the usual changespeed gear B, preferably on the propeller-shaft end as shown in Fig. 3, a gear unit comprising a free-wheel clutch 6 and means for bridging the free-wheel to effect a separate forward speed. Applying a brake band 15 to a planet-carrying drum 7 causes the power to pass through a train 1, 3, 13, 11a, 11, 12, 14, 2, so effecting an overdrive of the propeller shaft 2 with the free-wheel 6 overrunning. The invention also comprises means by which the driver according to the position of a hand lever 32, Fig. 2, may have as alternatives (1) the possibility of overdrive, (2) ordinary gear-box drive with freewheeling, and (3) ordinary gearbox drive without free-wheeling. The overdrive is brought in in one way only. It is only when the accelerator pedal 51b is in the partially - raised position shown that there is sufficient engine suction to pull down a diaphragm 19, Fig. 6, against a spring 22 to tighten the brake 15. For the suction in a pipe 23a, Figs. 1 and 4, to be passed on to the servo cylinder 20, a floating double-seated valve 24 must be in its open or depressed position. Otherwise the cylinder 20 is connected to atmosphere at 24a. For the valve 24 to be open, a lever 28 which passes under it must be in the depressed position shown in Fig. 2. A selector bar 31 of the main gear box B is in the withdrawn position shown when the gear-box high speed is in operation, so allowing the lever 28 to fall. At other gear box speeds, the bar 31 is farther to the right, rendering it impossible for the lever 28 to fall, and so rendering it impossible to bring in the overdrive. The hand lever 32 has a heel 43 adapted to pass under a lug 28b on the lever 28 so that the driver can at any time, by moving the lever 32 one step to the left of Fig. 2, cut out the possibility of overdrive according to (1) above. When the brake 15 is applied by suction in the cylinder 20, Fig. 6, a stem 18 is pulled downwards, carrying with it a sleeve 17a. A spring 49a, Fig. 2, then asserts itself to cause a toggle 46 to hold the sleeve 17a down and so lock the overdrive in action. The toggle can be broken to release the overdrive in different ways, for example by a full depression of the accelerator 51b, upon which a lost motion link 51 strikes a lever 49 to the right so as to break the toggle. A driver naturally does this in breasting a hill. The toggle 46 can also be broken by a leftward pull in a second lostmotion link 44, which is consequent on a raising of the lever 28, in turn consequent either on the rightward shift of the selector 31 or on the leftward turn of the hand lever 32. A lever 29 connects the link 44 to the pivot shaft 30 of the lever 28. So far considered, the driver has had the option of conditions (1) and (2) above, and a dog clutch 3, Fig. 3, provided for loc ing the free-wheel out has remained in the position shown, serving only to pass on the overdrive when required, the free-wheel 6 operating at other times. The driver can at any time realize condition (3) by moving the dog clutch 3 to the right so as to engage teeth 41 on the driven member 5 of the free-wheel without disengaging spline teeth on the enveloping sleeve 13. A lever 37 engaging the dog clutch 3 passes up adjacent the hand lever 32 and has a mortice 36 at its upper end. In the mid position of the hand lever 32, in which the overdrive has been cut out by raising the lever 28, a spring bolt 35 on the lever 32 can be lowered at will to engage the mortice 36. Further leftward displacement of the hand lever 32 then carries the dog clutch 3 to the right, locking the free-wheel 6 and realizing condition (3). The free-wheel is locked out automatically at any time on putting in reverse in the main gear box B. A reverse gear 52, in sliding to the right into mesh, strikes a distance bar 53 which thrusts the dog clutch 3 to its locking position. In starting, the driver passes through lower to top gears. The overdrive then operates on raising the accelerator 51b, unless the hand lever 32 has been put in a vertical position. If high gear is engaged with the accelerator depressed, the overdrive is not engaged. Silent operation and saving of fuel when coasting are obtained. A brake-applying spring 17, Fig. 6, eliminates any drawback caused by wear in the brake 15.