Patent GB-632292-A (GB)
Title: Improvements in or relating to epicyclic transmission gears
IPC: F16H3/66
Filed: 1945-07-02
Abstract: 632,292. Change-speed epicyclic gearing. RAVIGNEAUX, P. July 2, 1945, No. 16774. [A Specification was laid open to inspection under Sect. 91 of the Acts, Dec. 30, 1945]. [Class 80 (ii)] In change-speed gearing in which five speed ratios are obtainable by interchanging the operative connections of four epicyclic elements, the elements comprise a sun gear and a planet carrier either of which may be freed, clutched to a driving shaft or stationed, a sun gear which may be stationed or freed, and a driven annulus. As shown, alternative nested driving shafts m<1>, m<2>, Fig. 3, powered through friction clutches (not shown), preferably of the kind described in Specification 502,703, carry respectively a sun M<1> and a planet carrier M<2> whose interengaging planets S<1>, S<2> mesh, the one with the sun M<1> and the driven annulus R, and the other with a second sun F journalled on the shaft m<1>. The carrier M<2> is preferably stationed by symmetrically acting positive detents (not shown). The pinions M<1>, F are alternatively stationed by engaging friction discs F<1>, F<11>, slidably splined thereon, between braking members P<1>, P<11> on the gear casing and a central braking member L<2>, moved axially, by screwed engagement with the casing, upon partial rotation through a toothed quadrant (not shown) engaging the toothed exterior of the member. Driving through the pinion M<1>, reverse and first forward gears are engaged by stationing the members M<2>, F respectively. For second gear, the carrier M<2> alone is powered and the member F is stationed. In third gear, which is direct drive, the gearing is locked solid by driving through both members M<1>, M<2>, simultaneously. An overdriving fourth gear is provided by driving through the member M2 and stationing the member M<1>. Lubrication is provided from a pump (not shown) through passages d .... d<2>, gaskets a .... c preventing leakage. The disc F<11> may be rigid with a slidable pinion F. Clutch operation may be manual or electro-hydraulic. In Fig. 9 (not shown) all the members F, M<1>, M<2> are controlled by electromagnetically-operated friction brakes, the armatures of which are slidably splined to the members and co-act with magnets in screwed engagement with the casing to allow air gap adjustment. The driving clutches may be mechanically, electromagnetically or otherwise operated and lubrication may be by pump or gravity. In a similar form, Fig. 10 (not shown) the driving clutches are brought within the gear casing, both clutches and brakes being electromagnetically-operated. In this case, the armatures are rigidly connected to their members which themselves move axially upon clutch and brake operation. In Fig. 6 (not shown) the planets S<1>, S<2> are replaced by interengaging planets between the pinion F and annulus R and separate single planets between the pinion M<1> and annulus R. In a further modification, giving five forward speeds, the planets S2, Fig. 11, are between the pinion F and annulus R, and interengage the planets S<1> meshing the pinion M<1>. With the operative connections as in Fig. 3, except that the member M<1> is stationed in third gear and the member F in fifth, reverse becomes first gear, first gear becomes second and so on. Reverse may be provided by stationing the annulus R and driving through the pinion M<1>, a clutch member R<2> on the driven shaft being slidden to engage the carrier M2. The Specification as open to inspection under Sect. 91 comprises also further forms of epicyclic gearing in some of which the annulus is not the output member, and gives details of mechanical and electromagnetic brake constructions. In Fig. 11 (Cancelled) the carrier D of interengaging planets S<1>, S<2> is the output member, and the pinion M<1> is duplicated to allow convenient positioning of the clutches and brakes. The pinion M<1> and annulus M2 are alternatively powered from a driving shaft M, Fig. 11 (Cancelled) through electro-magnetically-operated clutches, and electromagnetically-operated brakes act on the duplicate pinion M<11>1, the annulus D and the pinion F. In a similar arrangement the annulus is duplicated instead of the driving pinion. Means for stationing the member M<2>, Fig. 3, are described comprising linked rotary cams engaging diametrically opposed slots in the rim M<12>, and means for controlling the two-way braking member L<2>, Fig. 3, consist of a cam 3, Fig. 5 (Cancelled), which is turned to drive back spring-loaded rods 4 positioning the quadrant operating lever L whilst eccentrics 5 controlling the rods 4 are adjusted through a hand lever (not shown). Various modified forms of electro-magnetically-operated brakes are described, including a rotating disc clamped between a stationary magnet and armature, and rotating magnets co-acting with fixed armatures. Air gap adjustment means are also described, including axial rods connected to a stationary electromagnetic member and having variable screwed engagement with a co-acting stationary member on the gear casing. A modification of Fig. 9 is shown in which the members M<1>, F, having armatures fast therewith, are arranged to slide together so that the air-gaps of both corresponding brakes can be simultaneously adjusted by screwing only one of the stationary magnets relative to the casing. This subject-matter does not appear in the Specification as accepted.