Abstract: A planetary gear unit made up of a number of inter-connected co-axial three element planetary gear trains (12, 13) each including a sun (15, 19) a planet carrier (17, 21) and an annulus (14, 18). One (12) of the planetary gear trains is a dominant train with a first element (14) connected to an input member (10) of the unit and a second element (17) connected to an output member (11) of the unit. The remaining train or trains (13) of the unit are connected to the third element (15) of the dominant train to vary, by the use of associated clutches (C1, C2, C3, C4) acting between elements of the trains and ground, the direction and speed of rotation of the third element (15), thus providing a number of overall gear ratios from the unit.

Abstract: A control system for the co-ordination of the operation of first and second implements mounted at spaced locations relative to the intended direction of travel of a tractor vehicle. The system can be used to co-ordinate the operation of spaced parts of a larger common implement (e.g. spaced shares on a long plough) or completely separate implements (e.g. ploughs mounted one on the front and the other on the rear of the tractor vehicle). The control system includes actuators for controlling the operation of the first and second implements, a speed sensor for sensing the forward speed of the tractor/implement combination, sensors to indicate the operating condition of the implements and an implement spacing compensation means which allows adjustment of the co-ordination of the operation of the implements dependent on the spacing between the implements.

Abstract: A gear unit provides a number of operative ratios engaged by fluid pressure operated clutches operated by clutch actuators. These actuators are controlled by two-position flow reversing valves, one valve for each fluid pressure operated actuator. These valves are hydraulically connected in series with at least one actuator connected downstream of the last valve in the series connection and at least one actuator connected between each valve of the series. A valve control means is provided for controlling the operating sequence of the valves so that by changing the operative condition of one valve at a time the operative ratio of the gear unit can be changed to the next adjacent ratio provided by the unit in a progressive manner throughout the entire ratio range of the unit.

Abstract: A transmission selector mechanism including two selector members (50, 51) connected with two coupling members (6, 7) each coupling member being axially slidable in both directions either side of a neutral position to couple a selected one of a pair of gears (10, 12: 11, 13) to an associated shaft (4, 5). The coupling members are connected with the selector members via an epicyclic gear train (56, 55, 54, 52). A first element (52) of the epicyclic is connected with one selector member (50), a second element (56) of the epicyclic is connected with one coupling member (6), and a third element (55) of the epicyclic is connected with the other selector member (5) and the other coupling member (7). The arrangement is such that by appropriate movement of the two selector members (50, 51) both coupling members (6, 7) can be positioned either on the same or opposite sides of their respective neutral positions.

Abstract: A transmission ratio selector mechanism for a transmission having two ratio selector couplers both of which must be engaged to provide drive through the transmission. The selector mechanism includes a selector shaft which is rotatable about its longitudinal axis and also axially moveable parallel to its longitudinal axis. Rotation of the selector shaft is arranged to operate one of the couplers via a mechanical linkage including a twin-armed member and a pivoted lever while axial movement of the shaft operates the other coupler via a fluid pressure-operated actuator and an associated control valve mechanism. An interlock is provided to ensure that the fluid pressure-operated coupler is always engaged before the mechanically operated coupler. The interlock comprises a formation which is movable with the shaft and cooperates with a formation movable with the coupler which is to be engaged first.

Abstract: Gearbox selector forks are commonly mounted for axial movement on a supporting rail which is rigidly mounted in the gearbox casing. When the fork is moved axially along the rail to move a coupling sleeve it can tilt and jam on the rail if it experiences excessive actuation loads which may inhibit or at least delay the operation of the associated synchromesh unit and engagement of the required gear. The present invention overcomes this problem by providing a support rail 14 which is itself axially displaceable against the action of a resilient means 32 thereby ensuring that the required selector fork 16 movement for gear engagement may be achieved even when the fork 16 is jammed on the support rail 14.

Abstract: A gear coupler for coupling a gear to a shaft includes a first coupling member which is connected for rotation with the shaft and a second coupling member which is connected for rotation with the gear and engageable by the first coupling member. The second coupling member is capable of limited circumferential movement relative to the gear to allow the first and second coupling members to engage each other without the need to rotate the gear. The advantage of this arrangement is that gears can be engaged without the operator needing to exert excessive actuation force on any actuating system which controls the movement of the coupler.

Abstract: A selector mechanism for a gearbox in which speed change couplers (28, 29) and a range change coupler (34) are operated by the same selector lever (47). Lever (47) operates the speed change couplers to engage a plurality of drive speeds when moved from a neutral plane to speed selection positions (1, 2, 3, 4) in a speed change gate and operates the range change couplers when moved to discrete range change positions (H,L). The selector mechanism is arranged so that on movement of the selector lever (47) out of the speed change gate towards a desired range change position (H, L) the range change coupler (34) is moved towards an engaged position for the desired range and on movement of the selector lever back towards the speed change gate from the desired range change position the movement of the range change coupler (34) is completed to engage the desired range.

Abstract: A vehicle such as a tractor having front and rear drive axles with crown wheel and pinions (10 and 11) driven from a prime mover (E) via an inter-axle differential (12). The rear drive axle has left and right hand brakes (40) and the inter-axle differential has a lock (22, 23, 24) for locking-up the differential. The lock is biased to an engaged condition by a spring (25) and an hydraulic actuator (27). A control system (CS) is provided which is arranged to engage the lock (22, 23, 24) when both rear axle brakes (40) are applied.

Abstract: A vehicle in which a prime mover drives a drive shaft via a torque converter and a multi-ratio transmission and in which a drive line independent of the torque converter and multi-ratio transmission is also provided from the prime mover to the drive shaft. The independent drive line provides an overdrive or underdrive function to extend the drive ratio range provided by the multi-ratio transmission and includes a clutch for the engagement of the additional ratio or ratios, and an interlock arrangement to prevent the simultaneous connection of drive to the drive shaft via the multi-ratio transmission and the independent drive line. When an overdrive function is provided, for example the interlock arrangement prevents engagement of the overdrive ratio unless the multi-ratio transmission is operating in its highest ratio when engagement of the overdrive is selected.

Abstract: A clutch actuating system which is particularly suitable for connecting drive to the front wheels of a four-wheel-drive tractor. The system includes an actuating member movable between a first position in which the clutch is disengaged and a second position in which the clutch is engaged. A pair of adjacent reaction members (27,29) encircle the actuating member and have mutually inclined wedging surfaces (30,31) on confronting faces. One (27) of the reaction members is connected with the clutch (25,26) which is of the toothed-dog type. A number of elongated toggle members (33) are connected at one end with the actuating member (32) and extend between the wedging surfaces of the reaction members at their other ends.

Abstract: A metering device for seed having a housing (7), a rotary metering member (27) that is rotatably mounted on a shaft 32 in open slots (25, 26) in a pair of side walls (8, 9) of the housing with the axis of rotation of the shaft extending transversely to the side walls. The rotary metering member and shaft are removable from the housing through the slots in a direction extending laterally of the axis of rotation and a closure member (36) is provided which is pivotally connected to the housing so as to extend across and close the ends of the slots (25, 26), thus retaining the rotary metering member (27) in position. Removal of the rotary metering member is therefore simply achieved by releasing the closure member pivotting it away from the housing and withdrawing the metering member and shaft laterally through the now open ends of the slots.

Abstract: A system for the control of a fluid flow control valve which controls the supply of fluid to an actuator to control the movement of a component such as a tractor implement hitch in response to a selected operating parameter such as hitch position or draft force. The system enables the desired value of the selected parameter to be set and this desired value is compared with the actual sensed value of the parameter to provide a parameter error signal. A start-up control function is provided to improve the initial speed of response of the system. The start-up control function is arranged on each detection of a parameter error signal to apply a start-up signal to the valve to initiate movement of the component and, if no movement results, to increase the start-up signal until movement of the component is detected whereupon the increase in the start-up signal is stopped and the magnitude of the signal applied to the valve is dependent on the parameter error signal so as to tend to reduce the error signal to zero.

Abstract: A tractor implement draft force control system in which desired and actual implement draft force values are compared to provide a draft force error signal. The system is responsive to the error signal to control the working depth and hence the draft force of the implement. A deadband operates on the error signal to render error signals within the deadband ineffective to control the working depth of the implement and a deadband control means adjusts the width of the deadband so that the deadband width is maintained dependent on components of the error signal above a predetermined frequency. Thus the system can be arranged not to respond to high frequency spurious components of the draft force signal but is able to respond to the lower frequency components of this signal which are representative of the true draft force variations.

Abstract: A power take-off control lever arrangement in which a single control lever 32 controls an engine speed power take-off clutch C2, a ground speed power take-off clutch C2 and a power take-off brake B. The control lever 32 is movable between positions C1' and B' in which switches 28 and 29 are operated to initiate engagement of the engine speed clutch C1 and brake B respectively which are both hydraulically operated. Lever 32 is also movable against the action of spring loading 49, to a position G in which it engages a fork 43 of a mechanical actuating system 43, 41, 31 for the ground speed clutch C2. Movement of lever 32 from position G to position C2' moves the mechanical actuating system to engage clutch C2. Lever 32 is only movable from position C2' to positions C1' and B' via position G to ensure disengagement of the ground speed clutch C2 before initiation of the engagement of the engine speed clutch c1 or the brake B.

Abstract: Crop processing apparatus comprising crop processing means (18, 23, 24) driven by drive means (29) and an automatic control system comprising sensor means (50, 51) for sensing transmission loss in the drive means (29) and producing a corresponding transmission loss signal which is proportional to the load exerted by crop on the crop processing means, setting means (Sr) for selecting a desired level of crop load and producing a reference crop load signal (Sr) corresponding to a selected level of transmission loss, signal processing means (13) which compares the transmission loss signal with the reference crop load signal to produce a control signal (Se), and actuator means (14) that is controlled in accordance with said control signal and is effective to vary the rate of feed crop to the processing means to maintain a substantially uniform load of crop in the crop processing means. The transmission loss takes the form of relative rotation or slip between input drive and output driven shafts (31, 33).

Abstract: A vehicle cab 10 with a window aperture 11 closed by a pivotable glazing panel 12. The window aperture is of vertically tapering form such that the width `W` of the lower regions of the aperture is less than higher regions of the aperture and the glazing panel 12 is of a similar vertically tapering form. A glazing panel mounting structure 13 allows the glazing panel to be moved from a generally upright closed position to a generally horizontal open position 12' by raising the panel in a vertical sense so that the lower narrower portion of the panel is in alignment with a wider higher portion of the aperture and then pivoting the lower narrower portion of the glazing panel about a first generally horizontal axis 21 through the wider higher portion of the aperture to its generally horizontal open position.

Abstract: An electronic tractor hitch control system in which the position of an implement hitch relative to a tractor can be set using a main control operable by a tractor operator from his normal location on the tractor and can also be set using a secondary control located at a location remote from the normal operator's location, such as on the rear of the tractor fenders. The system is arranged so that any implement position signal set using the secondary control is opposed by a smaller hitch positioning signal generated within the system so that the speed of movement of the hitch in response to hitch positions set using the secondary control is moderated. The system also includes circuitry for detecting short circuits in parts of the system located in vulnerable locations.

Abstract: A combined hand and foot control for a prime mover throttle member 10 including a hand control 12, a foot control 13, and a combining device 14 for combining the hand and foot controls. The combining device includes a plastics support housing 14a,14b and a combining member 34 slidable within the housing in first and second opposite directions. A first cable linkage 17 connects the combining member 34 with the throttle member 10 so that movement of the combining member in the first direction moves the throttle member towards a fully open position. A spring 38 act to bias the throttle member towards an idle position and hence bias the said combining member 34 in the second direction via the first cable linkage 17.

Abstract: A seed drill comprising a frame (1), a beam (14) that is mounted on the frame (1) so as to extend transversely of the direction of forward motion of the drill and that has a plurality of coulters (5) mounted along the beam (14) so as to trail therefrom and engage the ground when in work, the beam (14) comprising a central beam portion (29) and an outer beam portion (30) each side that is pivotally connected to the central beam portion (29) so as to be pivotable upwards to a transport position, characterized in that a strut assembly (39) is provided at each side of the drill between the frame (1) and the respective outer end of the beam (14) so as to be inclined downwards towards said outer end when the outer beam portion (30) is lowered, and pivotal connections (45, 47) being provided between the ends of the strut assembly (39) and the frame (17) and the outer beam portion (30) so that the strut assembly (39) can pivot upwards with the outer beam portion (30) to the transport position, the pivotal connection