Improvements in and relating to folding frameworks and wheelchairs

Claim 2

A folding structure capable of use in a wheelchair or other vehicle, the structure comprising first and second side frames connected by first and second toggle braces at opposite ends of the side frames, the folding structure being characterised by the toggle braces (22, 22a) having respective central hinges having hinge axes parallel to and similarly offset from a central plane of the structure when the structure is in an erected position whereby the structure may be folded to bring the side frames (19, 20) adjacent to one another but offset in a direction parallel to said central plane, and bracing means (27, 28, 34) for holding the structure in said erected position and maintaining the side frames (19, 20) substantially parallel to one another when the structure is being folded.

Claim 3

A folding structure according to claim 1 wherein said bracing means comprises a linking element (27) interconnecting the toggle braces (22, 22a) from the region of their respective central hinges, a latching arm (28) pivotally mounted on one of the side frames (19), latch means (29, 30) for providing latching engagement between the latching arm (28) and linking element (27) when the structure is in its erected position thereby holding the linking element and said toggle braces against movement in a folding direction, and a bracing element (34) extending in a plane perpendicular to said central plane and pivotally mounted to opposite corners of the structure thereby maintaining the side frames parallel to one another.

Claim 4

A folding structure according to claim 2 wherein said toggle braces fold in a rearward direction and said latch means comprises an abutment element (29) on a forward portion of the linking arm (27) and positioned to abut the latching arm (28) when in the erected position thereby preventing folding movement of the toggle braces.

Claim 5

A folding structure according to claim 3, and further comprising a striker element (30) on the linking arm and positioned immediately to the rear of the latching arm when in the erected position and adapted to be displaced when the latching arm is pivotably displaced upwardly thereby initiating folding movement of the toggle braces.

Claim 6

A folding structure according to any one of claims 1 to 4, wherein said toggle braces (22, 22a) are each formed from a pair of generally U-shaped arms (35a, 35b) each of spring wire whereby the arms of the toggle brace can flex when strains are imposed on the structure when in use.

Claim 7

A folding structure according to any one of claims 1 to 5 wherein said bracing means comprises a linking element (27) which is of rod-like form and has upturned end portions (27a, 27b) providing hinge pins for said toggle braces.

Claim 8

A wheelchair having a folding framework incorporating the folding structure according to any one of claims 1 to 6 and further comprising wheels mounted on said side frames.

Claim 9

A wheelchair according to claim 7 and further comprising direct drive motors (23, 24) connected and mounted to drive wheels (25, 26).

Claim 10

A wheelchair according to claim 7 or claim 8 and further characterised by folding arm rests (30a) mounted on the respective side. frames (19, 20), each arm rest having a rear leg pivotally mounted at its lower region to the side frame and a front leg the lower end of which is engageable in a mounting bracket (32), the arm rest being formed from spring wire and the front leg being disengageable by flexing of the arm rest against its inherent resilience thereby permitting the arm rest to be pivoted downwardly to lie substantially within the perimeter of the side frame.

Claim 11

A motorised folding wheelchair comprising side frames mounting respective front and rear wheels, the rear wheels each having an electric motor connected thereto, the structure being adapted to carry an electric battery to drive the motors and control equipment for controlling the motors, front and rear toggle braces each comprising two hingeably connected arms extending between the front and rear ends of the side frames, the wheelchair being characterised by a linking element (27) interconnecting the front and rear toggle braces (22, 22a) at the region of central hinges thereof, the hinges being similarly offset relative to the fore/aft central plane of the wheelchair, a latching arm (28) hingeably mounted to one of the side frames (19) about an axis substantially parallel to the linking element, the linking element carrying latch means (29, 30) engagable with the arm when it is in a downwardly displaced locking position to hold the toggle braces in an extended and locked position in normal use, and a diagonal bracing element (34) pivotally connected adjacent opposite corners of the structure and extending below the linking element and latching arm, whereby folding of the wheelchair is initiated by upward displacement of said latching arm which engages with the latch means of the linking element to displace the linking element rearwardly thereby causing said toggle braces to commence folding.

Claim 12

A motorised folding wheelchair comprising side frames mounting respective front and rear wheels, the rear wheels each having an electric motor connected thereto, the structure being adapted to carry an electric battery to drive the motors and control equipment for controlling the motors, front and rear toggle braces each comprising two hingeably connected arms extending between the front and rear ends of the side frames, the wheelchair being characterised by a linking element (27) interconnecting the front and rear toggle braces (22, 22a) at the region of central hinges thereof, the hinges being similarly offset relative to the fore/aft central plane of the wheelchair, a latching arm (28) hingeably mounted to one of the side frames (19) about an axis substantially parallel to the linking element, the linking element carrying latch means (29, 30) engagable with the arm when it is in a downwardly displaced locking position to hold the toggle braces in an extended and locked position in normal use, and a diagonal bracing element (34) pivotally connected adjacent opposite corners of the structure and extending below the linking element and latching arm, whereby folding of the wheelchair is initiated by upward displacement of said latching arm which engages with the latch means of the linking element to displace the linking element rearwardly thereby causing said toggle braces to commence folding.

Claim 13

A wheelchair according to'claim 10, wherein said electric motors are directly coupled to respective rear wheels and said offset of the hinges causing the motors to overlap in a folded position.

Claim 14

A folding structure capable of use in the framework of a folding wheelchair, the structure comprising first and second side frames connected by toggle braces which brace apart the side frames when in an extended condition, and characterised in that each toggle brace (22, 22a) comprises first and second generally U-shaped arms (35a, 35b) hingeably interconnected at the base of the U-portions, each arm being formed of spring wire thereby providing flexibility in the structure.

Claim 15

A folding structure capable of use in the framework of a folding wheelchair, the structure comprising first and second side frames connected by toggle braces which brace apart the side frames when in an extended condition, and characterised in that each toggle brace (22, 22a) comprises first and second generally U-shaped arms (35a, 35b) hingeably interconnected at the base of the U-portions, each arm being formed of spring wire thereby providing flexibility in the structure.