Wheel suspension and retraction apparatus
A wheel suspension and retraction apparatus ( 2 ) for an amphibious vehicle comprises a suspension unit having transverse upper and lower suspension links ( 4, 8 ); spring and damper unit ( 12 ), and suspension upright ( 6 ) supporting wheel ( 10 ), and pivotally connected to outboard ends of links ( 4 and 8 ). The wheel retraction mechanism has a retraction linkage ( 14, 16, 18 ), pivotably connectable to the vehicle, and an actuator ( 38 ) for moving the wheel suspension between a protracted position for land use and a retracted position for use on water. The retraction mechanism supports the suspension unit spaced apart transversely from the vehicle. Tie bar ( 16 ) is connected to upper retraction arm ( 14 ) at an intermediate location ( 30 ) to ensure a large angle of tilt on retraction, to ensure that the wheel is retracted above hull line ( 156 ). The wheel suspension does not have to be compressed on retraction.
1. A wheel suspension and retraction apparatus for an amphibious vehicle comprising:
a suspension unit having an upper suspension link, a lower suspension link and a suspension upright for supporting a wheel, said suspension upright pivotally connected to outboard ends of the upper and lower suspension links;
a wheel retraction mechanism having a retraction linkage pivotally connectable to the vehicle and an actuator for pivoting the retraction linkage between a protracted position and a retracted position; wherein:
the retraction mechanism supports the suspension unit spaced apart from the vehicle with the suspension unit supported on the vehicle only via the retraction mechanism;
wherein when the retraction linkage is protracted then the retraction linkage holds the suspension unit in a deployed wheel position for operation of the vehicle on land; and
on retraction, the retraction mechanism lifts the suspension unit upwardly to a retracted wheel position, for use of the vehicle on water.
2. The wheel suspension and retraction apparatus of claim 1 , wherein in use the retraction linkage is pivotally attached to an inboard end of the upper suspension link and to an inboard end of the lower suspension link.
3. The wheel suspension and retraction apparatus of claim 1 wherein in use the retraction mechanism is operable to rotate the suspension unit upwardly and in an inboard direction.
4. The wheel suspension and retraction apparatus of claim 3 wherein the retraction mechanism is operable to tilt the suspension upright whilst lifting the suspension unit.
5. The wheel suspension and retraction apparatus as claimed in claim 1 wherein the retraction linkage comprises:
an upper retraction link pivotally connected at an outboard end thereof to the upper suspension link and pivotally connectable at an inboard end thereof to the vehicle,
a lower retraction link pivotally connected at an outboard end thereof to the lower suspension link and pivotally connectable at an inboard end thereof to the vehicle; and
a tie bar pivotally connected between the upper retraction arm and the lower retraction arm.
6. The wheel suspension and retraction apparatus of claim 5 wherein the tie bar is pivotally connected to the upper retraction link at a point on the upper retraction link between inboard and outboard ends of the upper retraction link.
7. The wheel suspension and retraction mechanism of claim 5 wherein the tie bar is pivotally connected to the lower retraction link at the outboard end thereof.
8. The wheel suspension and retraction apparatus of claim 5 wherein the lower retraction link is longer than the upper retraction link.
9. The wheel suspension and retraction apparatus as claimed in claim 5 wherein the actuator is a hydraulic ram pivotally connected at an outboard end thereof to the lower retraction link and pivotally connectable at an inboard end thereof to the vehicle.
10. The wheel suspension and retraction apparatus of claim 5 wherein the actuator is a hydraulic ram pivotally connected at an outboard end thereof to the upper retraction link and pivotally connectable at an inboard end thereof to the vehicle.
11. The wheel suspension and retraction apparatus of claim 1 wherein the upper suspension link is shorter than the lower suspension link.
12. The wheel suspension and retraction apparatus of claim 1 wherein the upper suspension link and/or the lower suspension link are each in the form of a wishbone.
13. A wheel suspension and retraction apparatus for an amphibious vehicle comprising:
a suspension unit having an upper suspension link, a lower suspension link and a suspension upright for supporting a wheel, said suspension upright pivotally connected to outboard ends of the upper and lower suspension links;
a wheel retraction mechanism having a retraction linkage pivotally connectable to the vehicle and an actuator for pivoting the retraction linkage between a protracted position and a retracted position;
wherein the retraction linkage comprises a lower retraction link pivotally connected at an outboard end thereof to the lower suspension link and pivotally connectable at an inboard end thereof to the vehicle;
wherein when the lower retraction link is protracted the retraction linkage holds the suspension unit in a deployed wheel position for operation of the vehicle on land; and
on retraction, the retraction mechanism lifts the suspension unit upwardly to a retracted wheel position, for use of the vehicle on water.
14. A wheel suspension and retraction apparatus as claimed in claim 13 , wherein the retraction linkage is pivotally attached to an inboard end of the upper suspension link and to an inboard end of the lower suspension link.
15. The wheel suspension and retraction apparatus of claim 13 wherein the retraction mechanism is operable to rotate the suspension unit upwardly and in an inboard direction.
16. The wheel suspension and retraction apparatus of claim 13 wherein the retraction mechanism is operable to tilt the suspension upright whilst lifting the suspension unit.
17. The wheel suspension and retraction apparatus as claimed in claim 13 wherein the retraction linkage further comprises an upper retraction link pivotally connected at an outboard end thereof to the upper suspension link and pivotally connectable at an inboard end thereof to the vehicle, and
a tie bar pivotally connected between the upper retraction link and the lower retraction link.
18. The wheel suspension and retraction apparatus of claim 17 wherein the tie bar is pivotally connected to the upper retraction link at a point on the upper retraction link between inboard and outboard ends of the upper retraction link.
19. The wheel suspension and retraction mechanism of claim 17 wherein the tie bar is pivotally connected to the lower retraction link at the outboard end thereof.
20. The wheel suspension and retraction apparatus of claim 17 wherein the lower retraction link is longer than the upper retraction link.
21. The wheel suspension and retraction apparatus of claim 13 wherein the upper suspension link is shorter than the lower suspension link.
22. The wheel suspension and retraction apparatus of claim 13 wherein the upper suspension link and/or the lower suspension link are each in the form of a wishbone.
23. The wheel suspension and retraction apparatus of claim 13 wherein the lower retraction link and/or the upper retraction link are formed as a pair of rigid members.
24. The wheel suspension and retraction mechanism of claim 13 wherein the upper retraction link and/or the lower retraction link are each configured as an “H” frame.