Patent GB-1384732-A (GB)
Title: Planetary reduction gear drive
IPC: F16H1/46
Filed: 1972-03-21
Abstract: 1384732 Toothed gearing; variable speed gearing FAIRFIELD MFG CO Inc 21 March 1972 [9 April 1971] 13249/72 Headings F2Q F2D F2C and F2E A planetary reduction gear drive, for an hydraulic motor powered wheel hub 24 (as shown), or a chain sprocket (332), Fig. 12 (not shown), for driving a drum of a transit mix concrete mixer, comprises a flanged hollow spindle 48 secured to a fixed structure 38 on the vehicle and rotatably supporting a hub assembly 92, 94, an hydraulic drive motor 42 having a shaft 46 coupled by a sleeve 78 to a shaft portion 72 of an input shaft 50 carrying on a second portion 74 thereof a sun gear 150 meshing planet gears 120 of stepped planet gears 120, 122, the planet gears 122 meshing on output ring gear 30 on hub portion 94, and planet gears 120 meshing a fixed ring gear 26 on the fixed hollow spindle 48. As shown, the arrangement is of the pick-off type in which further gear ratios may be obtained by simply removing an end cover 34 and substituting different gear clusters and arranging the sun gear on the shaft portion 74 to mesh either the planets 120 (as shown) or the planets 122 (Fig. 7, not shown). Alternatively, Fig. 8 (not shown), a two-speed gear with an intermediate neutral arrangement is illustrated operated by a simple push-pull manual selector gear rod (200) arranged to move the output shaft (50<SP>1</SP>) within its coupling sleeve (78<SP>1</SP>) to engage a splined portion (178) with one or other splined bore or two axially located suns (150<SP>1</SP>, 174<SP>1</SP>), the suns being relieved of splines at the central intermediate, e.g. neutral position (178a). In Fig. 9 (not shown), the axially located suns (150<SP>11</SP>, 174<SP>11</SP>) have facial clutch teeth (228, 230), and are freely mounted on an axially movable sleeve (216) having corresponding facial clutch teeth (224, 226) and slidably splined on the output shaft 50, a fluid pressure or solenoid actuated plunger (248) in the fixed housing (48<SP>11</SP>) cam actuating at (240) an axially movable push rod (232) to rightwardly move the push rod for clutching at (224, 228) the sun (150<SP>11</SP>), a return spring (244) serving on release of the power actuator (248) to return the sleeve (216) to de-clutch sun (150<SP>11</SP>) and clutch at (226, 230) sun (174<SP>11</SP>). A further fluid pressure or solenoid actuated plunger 276 in the housing, when operated, cam actuates an axially movable push rod (262) carrying a facially toothed disc (256) serving as parking brake detent to engage and lock, i.e. station the sleeve (216) and sun (150<SP>11</SP>) thereby locking the gear unit against drive. Alternatively simple parking brake detents are illustrated in Fig. 2, as a radially movable pin 158 engaging recesses 156 formed on the periphery of the drum 92, and in Fig. 11 (not shown), as a caliper'brake (330) engageable with a disc (316) fast on the wheel hub (92). In Fig. 10 (not shown), the axially fixed suns (150<SP>111</SP>, 174<SP>111</SP>) are selectively clutched to the output shaft by spring released multi-disc friction clutches (288, 290) hydraulically actuated via axially movable push rods (232, 302). Both clutches may be applied simultaneously to lock gear unit to provide a parking brake action. In Fig. 13, one or other sun only is used, as in the Fig. 2, embodiment, with suitable spacers for axial location thereof, the output shaft carrying a spring (384) by which the output shaft is normally spline engaged with the sun, a reversible cap (344) having a projecting dome (346) by which, when the cap is manually reversed, the output shaft is leftwardly moved against the spring bias to declutch the splined engagment with the sun for free-wheeling of the drive.