Patent GB-484198-A (GB)
Title: Automatic change speed gear
IPC: F16D47/00
Filed: 1936-09-26
Abstract: 484,198. Change - speed gearing; friction and overload - release clutches. HENRIOD, C. E. Sept. 26, 1936, Nos. 26153 and 26155. Convention dates, Dec. 20, 1935 and July 22, 1936. [Class 80 (ii)] Automatic control mechanism for change-speed gearing (not shown) comprises a centrifugal clutch for introducing the lowest speed, higher speeds being introduced successively, as the load reduces, by additional clutches previously held open by the torque acting on balls 64, Fig. 1, located in cam-recesses in opposed plates of such clutches. Such torque-action may be opposed by spring and /or centrifugal force. In the form shown in Fig. 1, the driven plate 61 of the lowestspeed clutch is connected to the final driven shaft 25 through a drum 23 and a reducing train (not shown), the driven plate 60 of an intermediate speed clutch being similarly connected through a drum 27 and a reducing train of different value, whilst the driven plate 59 of a direct drive clutch is splined to a drum 30 integral with the driven shaft. The driving plates 14, 56, 57, 58 of all the clutches are driven from the first plate 14 which is integral with the engineshaft 5. In operation, as the engine speed increases from rest, all the plate clutches are simultaneously tightened by overhanging centrifugal masses 63 which pivot outwards against return springs and screw along bolts 55 secured to the driving plate 14. The standstill load, say of a vehicle, will be sufficiently high to cause the torque to act on the balls 64<1> and 642 and separate the plates 14, 56, 57 of the second- and high-speed clutches in its passage to the low-speed clutch-plates 57, 58. If the torqueload on the low-speed clutch-balls 64 permits, the low-speed clutch will then engage under the influence of the centrifugal masses 63, and drive the load. With reduction in load, the balls 64<1> of the second-speed clutch roll back into their recesses and allow the second-speed clutch 60 to engage, whereupon a one-way detent in the low-speed train overruns, the lowspeed clutch 61 remaining engaged. Further reduction in load allows the direct-drive clutch 59 to engage. The second-speed train also includes a one-way detent so that both low- and second-speed trains overrun, all the clutches being then engaged. Relative rotary movement between the driving clutch-plates 14, 56 &c., is limited by pegs 66, engaging arcuate slots in the plates. In the form shown in Fig. 3, the control device is driven through a separate centrifugal main-clutch 70, between the engineflywheel 6 and an intermediate shaft 51 having a flange 14, forming the driving element of the direct-drive clutch 59, which, like the secondspeed clutch 6Q is engaged by springs 69<2> and disengaged by the torque acting through balls 64<2>. The said balls 64<2> are located in pockets in flanges 72<2>, 72<1>, which pass the drive on to the adjacent clutch through one-way clutches 73<2>, 73<1>, which overrun successively as higher speeds engage. Initially drive passes through the centrifugal clutch 70, shaft 5<1>, flange 14, balls 64<2>, flange 722, one-way clutch 73<2>, secondspeed clutch flange 14<3>, balls 64<1>, flange 72<1>, one-way clutch 73<1>, disc coupling 61, drum 23 and a low-speed train, not shown, to the final driven shaft 25. The high starting load causes both clutches 59, 60 to be disengaged by their balls 64<2>, 64<1>. With reduction in load the clutches 60, 59 engage in succession giving respectively second-speed through a drum 27 and direct-drive through a drum 30. Pins 66<1> limit relative movement between respective clutch-flanges such as 14<3>, 72<1>. The form shown in Fig. 4 uses separate centrifugal engaging means for all three speeds and also has a different driving arrangement for the speed-trains. The lowest speed is by way of a centrifugal clutch 110, driving an outer sleeve 89, which, through a reduction train (not shown) drives back to an inner sleeve 112, integral with a driving plate 113 of the secondspeed clutch. Starting torque being high, both second-speed and direct-drive clutches 124, 125 will be disengaged by their balls 120, 121 as the torque passes the lowest speed from the plate 113 through the balls to a direct-drive clutch-plate 116, splined on the final driven shaft 114, which will thus be driven in lowest speed. With increase of speed and /or reduction in load the effect of the balls 120 is overcome by the outward pivotal movement of overhanging centrifugal masses 119, which screw along threaded bolts 117, secured to the plate 113 and act only on an intermediate plate 115 to engage the second-speed clutch-disc 124. A free-wheel in the low-speed train then overruns, and a second-speed drive is obtained through the centrifugal clutch 110, sleeve 89, a second-speed reduction train (not shown) return sleeve 122, second-speed clutch 124, balls 121 and plate 116 to the driven shaft 114. With further increase in speed and /or reduction in load, centrifugal masses 119a thread along bolts and act on the outer plate 116 to press together all the clutch plates. Second- and low-speeds then overrun and drive passes directly from the engine flywheel 6 to the driven shaft 114 by way of the clutch 125. Fig 5 shows an incomplete modification of this form, the centrifugal clutch 110, Fig. 4, being used but is omitted for the sake of clarity. In this form the secondspeed clutch 124 disengages when the directdrive clutch 125 engages. The clutch-plates 113, 115, 116 are arranged as in Fig. 4, but in this case the second-speed clutch 124 is engaged solely by springs 128, whilst the direct-drive clutch 125 is engaged solely by centrifugal masses 119 screwing along bolts 117. With the lowest speed driving, both clutches 124, 125 are disengaged (Fig. 5). Reduction in load causes the balls 120 of the second-speed clutch to be forced into their recesses by the loading springs 128, thus engaging the second-speed clutch 124. Further reduction in load and/or increase in speed causes the centrifugal masses 119 to tighten the direct-drive clutch-plates 115, 116 and engage the direct-drive clutch 125, simultaneously disengaging the second-speed clutch 124. This is achieved by shaft-abutments 130, 131, which respectively limit leftward movement of the plate 113 and rightward movement of the plate 116. For the sake of clarity the recesses for the torque-responsive balls 120, 121, are shown extending radially, although actually they are arranged circumferentially. The balls 120 of the second-speed clutch are arranged at a greater radius than those 121 of the direct-drive clutch so as to be subject to less tangential force. Means may be provided for holding in second-speed against the effect of the masses 119. The Specification as open to inspection under Sect. 91, describes a complete change-speed gear, Figs. 1, 2, 3 (all Cancelled), having two epicyclic trains 32, 39, in series and rendered solid in succession. The driven shaft 25 of the change-speed gear drives the final output shaft 48 through an epicyclic reversing train controlled by sliding its planet-carrier 50. Automatic control is by three centrifugal and torque-responsive clutches 11, 12, 15 providing respectively low- and second-speeds and directdrive, by clutching drums 23, 27, 30. The epicyclic trains 32, 39 are similar, each comprising a driving sun-wheel 26, 29, respectively secured to the low-speed clutch-drum 23 and the second-speed drum 27. The sun-wheels each engage an internally- and externally-toothed planet-pinion 31, loosely and eccentrically mounted on a loose planet-carrier 32, or 39, permanently prevented from reverse rotation by pivoted pawls 36 engaging ratchet-teeth on the carrier. The planets 31 also engage looselymounted annuli, that 33 of the first train being fast to the sun-wheel 29 of the next train, the annulus 41 of which is keyed to the driven shaft 25 and integral with the driving sun-wheel 47 of the reversing train 50. Thus when the firstspeed clutch 11 engages its drum 23, drive passes through the two trains in series. Engagement of the second-speed clutch 12 causes the drive to pass only through the second train via the drum 27 and sun-wheel 29, the carrier 32 of the first train then overrunning. The clutch 15 passes the drive directly to the driven shaft 25 via its drum 30, both carriers then overrunning. The control clutches comprise segmental centrifugal clutch-shoes 11, 12, 15 pivoted respectively to driving plates 7, 8, 14. The driving plate 14 of the direct-drive clutch is fast to the driving shaft 5, whilst those 7, 8 of low- and second-speeds are both loose thereon and receive their drive as follows. The friction shoes 12 of the second-speed clutch have tails 21, bearing through transverse pins 22 on arcuate elements 16, projecting axially from the low-speed clutch-plate 7 into arcuate slots in the low-speed clutch-plate 8. Torque passes from the plate 8 to the plate 7 only through the projections 16, and in doing so acts on the tails of the second-speed clutch shoes 12 to tend to draw them out of engagement with the driven drum 27, thus subjecting them to torque, and centrifugal control. The torque acts through springs 18. Similarly torque reaches the second-speed clutch-plate 8 from the driving plate 14 through arcuate projections 19 on the plate 8 acting on tails on'the direct-drive clutchshoes 15, whereby the direct-drive clutch 15 is also torque- and speed-responsive. Thus under an initial starting load, both clutches 12, 15 will disengage and the drive will be picked up by the low-speed centrifugal clutch, the clutches 12, 15 introducing second- and high-speeds in succession as the load reduces and /or the speed increases. This subject-matter does not appear in the Specification as accepted.