Patent GB-376730-A (GB)
Title: Improvements in and relating to power transmission systems of automobile vehicles
Filed: 1932-03-12
Abstract: 376,730. Clutches and variable-speed gearing for automobiles. FLEISCHEL, G., BlÚneau, Yonne, France. March 12, 1931, No. 7701. [Class 80 (ii).] In power-transmission systems for automobiles of the kind in which variations of the speed of the driving - shaft, which may be due, in part, to variations of the load, effect automatically the operation of the main clutch, means, which may act by the said variations of speed or by acceleration and deceleration of the vehicle, are provided to control the said automatic action so as to ensure smooth engagement and disengagement of the clutch. Preferably, a source independent of those effecting the said control supplies the motive power operating the clutch. Means for automatically changing gear and reversing and, further, a low-speed drive overriding the main automatic control may be used. A variable-speed gear controlled, as in Specifications 356,139, 360,262, and 369,361, bv variations in the vacuum in the inlet conduit of the engine and of the pressure in the cooling- water system may be incorporated and such means may be used also for controlling the main clutch. Such a gear control is shown at 1 .. 7, Fig. 1, actuating a lever 14 which moves between contacts 19<1>, 19<2> controlling electromagnetic clutches 17<1>, 17<2> effecting reversal of drive between an independently driven shaft 16 and a cam shaft 15 carrying cams 12, 13 for gear-changing and a cam 20 for temporary release of the main clutch 9 during each gear-change. Cams 33, 33<1> on the shaft 15 break circuits to limit the rotation of the shaft. At low engine-speeds, the parts are in the position shown, with the lowest gear engaged, but with the clutch 9 disengaged by a cam 32 on a shaft 15<1> driven from an independent drive 161 through reversing electromagnetic clutches 311, 31<2> excited, respectively, by engagement of contacts 35<1>, 352 on a plate 34, secured on the shaft 15<1>, with a contact 36 on a lever 14<1>, which is controlled by a governor 23 driven by the engine. Manual adjustment of a roller 26 provides control of the range of effective engine speeds. Increase of engine speed moves the contact 36 into engagement with the contact 351 to rotate the shaft 15<1> and initiate clutch engagement, the plate 34 following-up the lever 14<1> and breaking contact, unless the load is insufficient to prevent further increase of engine speed, in which case the lever advances gradually to the stop 29<2>, where the clutch is fully engaged. The follow-up movement of the plate 34 ensures that the clutch engagement and disengagement are under critical automatic control whatever the speed of the driving-shaft below that necessary to drive the vehicle at bottom speed without clutch-slip. At greater speeds, the lever 14 engages the contact 19<1> to rotate the shaft 15 and change the gear, the clutch 9 remaining engaged except when momentarily disengaged by the cam 20 during gear-change. The control members 1 .. 5 may operate a floating lever actuating differentially both the gearcontrol lever 14 and the clutch-control lever 14<1>, the control 23 being dispensed with, and, in another construction, the vacuum and water controls are separated, both controls acting on the lever 14<1> and only the vacuum control on the lever 14. In order to obtain engagement of the main clutch at an engine speed higher than that which effects the disengagement, the device shown in Fig. 5 is used. A lever 14a is operated by the governor 23 and a lever 14b bears on a spring 25. On the lever 14b are provided a fixed contact point 43 and a point 44 which may be slid along the lever by the driver or automatically by means controlled by the load. The lever 14a engages with lost motion a lever 52, corresponding to the lever 141, Fig. 1, and carrying a contact 54 cooperating with strips 35<1>, 352 on a plate 34 as in that Figure. As the lever 14a is moved, its engagement with the lever 14b shifts from the point 43 to the point 44, to change the effective force of the spring 25, and the lost motion connection between the parts 14a, 52 ensures the actuation of the clutch at the desired different speeds. When the clutch 9 is of electromagnetic type, an additional control of the clutch engagement may be added, the use of the strips 35<1>, 35<2> being discontinued. The lever 52 engages only a contact 35<1> on the plate 34 and the lever 14b carries a contact 47 engaging a contact 48 connected through a resistance 51 with the electromagnet. During engine acceleration, the contact 48 is first engaged to produce partial clutching, subsequent engagement of the parts 52, 351 completing the clutch engagement. On movement of the lever 14a for clutch release, the contacts 48, 351 are simultaneously released at the lower speed and the additional clutch release operates abruptly. The contact 47 may engage in succession the contacts of a rheostat to effect more gradual clutch action. Superimposed upon, or independent of, the follow-up clutchcontrol system of Fig. 1, a control effective to disengage or engage the clutch wholly or in part, upon excessive acceleration or deceleration of the vehicle may be used. Alternative devices, Figs. 8 to 11 (not shown), for this purpose are operated by the inertia of weighted rotary and swinging masses to open and close circuits which excite the clutches 31, 32<2>, Fig. 1, or gradually excite the main clutch, when of electromagnetic type. The levers 14, 14<1>, controlled as in Fig. 1, may each actuate the clutches 17<1>, 17<2> on the shaft 15, the shaft 151 being omitted and the cam 20 so modified as to perform additionally the clutch-controlling function of the cam 32. To provide that the follow-up motion of the plate 34 takes place only while the engine is speeding up sufficiently to engage the main clutch fully for first speed, circuit-breaking cams are used on the shaft 15 or a shaft carrying the plate 34 is geared with the shaft 15 in such manner that the drive is operative only during the first part of the movement of the shaft 15. A system is described, Fig. 13 (not shown), in which the driver sets an electric switch for forward or reverse drive, with an intermediate neutral position, the cam shaft 15 being then driven in the appropriate direction by excitation of its clutches 17<1>, 17<2>. The whole automatic control is provided by the gear-control lever 14, which at the end of its movement on fall of speed actuates a sliding member performing the functions of the clutch-control lever 14<1>, a sliding plate equivalent to the rocking plate 34, Fig. 1, being provided. An auxiliary low-speed drive for manoeuvring may be brought into action at will and operates by disengaging or slipping the clutch when the vehicle speed tends to rise above a certain low limit. A centrifugal governor driven by the road wheels acts on a switch controlling the main clutch, if of electromagnetic type, or, otherwise, on auxiliary clutches such as 17<1>, 17<2>. Alternatively, apparatus which matches the engine and driving-axle revolutions and disengages and engages the clutch as the axle revolutions rise above or fall below a fixed proportion of the engine revolutions may be used, thus providing for variation of the speed.