Wheelchairs

Claim 2

Elevating means for use with a wheelchair of the type having supporting side frames, said elevating means comprising a pair of extendable frameworks each having a fixed part with means for securement to a respective side frame of wheelchair and a relatively vertically moveable supporting part, and hydraulically actuated lifting means connected between each fixed part and its respective moveable supporting part for moving said moveable support parts downwardly into engagement with a supporting surface to elevate said fixed parts and thereby lift an associated wheel chair.

Claim 3

Elevating means for use with a wheelchair as claimed in claim 1 in which each hydraulic means includes hydraulic rams.

Claim 4

Elevating means for use with a wheelchair as claimed in claim 2 in which said supporting part of each of said frameworks includes a bar which lies along a supporting surface when engaged therewith.

Claim 5

Elevating means for use with a wheelchair as claimed in claim 3 in which the hydraulic rams are supplied with hydraulic fluid from a common manually operable pump.

Claim 6

Elevating means for use with a wheelchair as claimed in claim 4 in which the hydraulic rams are hydraulically cross-connected so that the rams extend and retract equally.

Claim 7

Elevating means for use with a wheelchair as claimed in claim 5 in which each hydraulic ram includes a piston and a cylinder and said hydraulic rams are connected to the pump so that when pressure fluid is pumped in a direction from the pump said pressure fluid is supplied to one side of a piston in one of the rams, fluid from the other side of said piston of said one ram being transmitted to one side of the piston of the other of said rams, and fluid on the other side of the piston of said other ram being connected to relief on the pump.

Claim 8

Elevating means for use with a wheelchair as claimed in claim 6 in which the piston of each ram has a connecting rod which extends through the cylinder to one side of the piston, the diameter of one of the cylinders being smaller than the other to compensate for fluid transferred from said one cylinder to the other cylinder during operation.

Claim 9

Elevating means for use with a wheelchair as claimed in claim 3 in which each framework includes a pair of telescopic guide tubes, the guide tubes and hydraulic ram of each framework being angled to the supporting surface engaging bar so that the chair will be moved rearwardly relatively to the supporting surface engaging bars as the chair is elevated.

Claim 10

Elevating means for use with a wheelchair as claimed in claim 3 in which the supporting surface engaging bars are each inclined to the supporting surface when in a raised position with their forward ends lowermost.

Claim 11

Elevating means for use with a wheelchair as claimed in claim 4 in which the hydraulic rams are connected to the manually operable pump by flexible hydraulic pipes and are otherwise disposed so that a chair with said elevating means fitted thereto can be folded into a closed position.

Claim 12

Elevating means for use with a wheelchair as claimed in claim 1 in which said securement means clamp each of the two frameworks to a respective side frame of the chair in a readily releasable manner.

Claim 13

Elevating means for use with a wheelchair as claimed in claim 4 in which the manually operable pump incorporates means for selecting the direction of fluid flow through it.

Claim 14

Elevating means for use with a wheelchair as claimed in claim 12 in which the pump includes a piston which can be reciprocated in a pumping cylinder to promote a fluid pressure and selecting valve means having first and second ports connected to said hydraulic rams and means for selecting a pressure fluid flow path from the pumping cylinder to either of the first or second connecting ports.

Claim 15

Elevating means for use with a wheelchair as claimed in claim 13 in which the selecting valve means also provides a fluid flow path from that end of the first or second parts which is not connected into the pressurized flow path.

Claim 16

Elevating means for use with a wheelchair as claimed in claim 13 in which first and second non-return valves are provided in a fluid flow path on each side of the pumping cylinder and arranged so that fluid drawn into the cylinder through said first non-return valve is expelled under pressure through the second non-return valve.

Claim 17

Elevating means for use with a wheelchair as claimed in claim 15 in which the selecting valve means acts to divert pressurized fluid from the second non-return valve to a selected one of the connecting ports.

Claim 18

Elevating means for use with a wheelchair as claimed in claim 15 in which said pump has two cylinders and pistons.

Claim 19

Elevating means for use with a wheelchair as claimed in claim 17 in which the cylinders and pistons are co-axial and opposed, and a manually operated rocking mechanism is operatively connected to said pistons.

Claim 20

Elevating means for use with a wheelchair as claimed in claim 4 in which the pump is provided with means for clamping it to are of the sideframes of the chair.

Claim 21

Elevating means for use with a wheelchair as claimed in claim 12 in which the pump comprises a cylinder and a piston which can reciprocate in said cylinder, a pair of valves and means for selectively presetting the valves to either a first or a second position, said valves each having a respective valve member moveable with respect to the valve and co-operting with respective first and second seats such that when the valves are set in first position the valve member of said first valve co-operating with its first respective seat and acts as a to said cylinder and the valve member of said second valve co-operates with its second respective seat and acts as an outlet valve to said cylinder and when the valves are set in said second position the valve member of said first valve co-operates with its second respective seat and acts as an outlet valve to said cylinder and the valve member of said second valve co-operates with its first respective seat and acts as an inlet valve to said cylinder.

Claim 22

Elevating means for use with a wheelchair as claimed in claim 20 in which each of the valves can be set in a position such that the valve member can float between a neutral position and a position in which it co-operates with one of its valve seats to prevent flow of pressurized fluid from the cylinder, flow of fluid into the cylinder being allowed with the valve member in its neutral position or can be set on a position in which it co-operates with the other of its valve seats to prevent flow of fluid into the cylinder when a suction is drawn on the cylinder by movement of the piston.