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A wheelchair of the mid-wheel drive type has a chassis frame, a pair of from and rear link arms that are pivotally connected to the chassis frame. Front caster wheels and drive wheels are fixed to the front link arms. Rear caster wheels are fixed to the rear link arms. A coupling operatively connect

A wheelchair of the mid-wheel drive type has a chassis frame, a pair of from and rear link arms that are pivotally connected to the chassis frame. Front caster wheels and drive wheels are fixed to the front link arms. Rear caster wheels are fixed to the rear link arms. A coupling operatively connects each front link arm to an adjacent rear link arm to transmit pivotal movement of one of the front and rear link arm to an opposite pivotal movement of the other of the front and rear link arm.

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1. A wheelchair comprising: a substantially horizontal seat having a front end and a rear end, a substantially vertical back rest proximal the rear end of the substantially horizontal seat, and a central chassis frame;a pair of front link arms proximal the front end of the wheelchair, each front lin

1. A wheelchair comprising: a substantially horizontal seat having a front end and a rear end, a substantially vertical back rest proximal the rear end of the substantially horizontal seat, and a central chassis frame;a pair of front link arms proximal the front end of the wheelchair, each front link arm pivotally connected to the chassis frame at a respective first pivot axis, each front link arm having a portion extending forward of the first pivot axis and a rearward portion extending rearward of the first pivot axis;a pair of rear link arms proximal the rear end of the wheelchair, each rear link arm pivotally connected to the chassis frame at a respective second pivot axis rearward of the first pivot axis, each rear link arm having a portion extending rearward of the second pivot axis and a forward portion extending forward of the second pivot axis to overlap, at least in part, with the rearward portion of the corresponding front link arm;a pair of drive assemblies comprising a drive wheel, each drive assembly non-pivotally and fixedly mounted to at least one of the chassis frame or an adjacent one of the pair of front link arms; andthe rearward portion of each front link arm being coupled to the forward portion of the adjacent rear link arm to allow relative movement between each front link arm and the adjacent rear link arm such that when the front link arm pivots about the first pivot axis in a first direction, the rear link arm pivots about the second pivot axis in a second direction opposite the first direction. 2. The wheelchair according to claim 1, wherein each coupling comprises a stud which is received in a slot and wherein the stud is fixed to one of the rearward portion of the front link arms or the forward portion of the rear link arms and the slot is arranged in the other of the rearward portion or the forward portion. 3. The wheelchair according to claim 1, comprising a pair of shock absorbers which are pivotally connected to the chassis frame and to a respective rear link arm. 4. The wheelchair according to claim 1, wherein each drive assembly is non-pivotally and fixedly mounted to the respective front link arm. 5. The wheelchair according to claim 4, wherein pivoting the pair of front link arms in a counter clockwise direction provides a downward force on the drive assembly. 6. The wheelchair according to claim 4, wherein pivoting the pair of front link arms in a clockwise direction provides a downward force on a pair of rear casters coupled to the rear link arms. 7. The wheelchair according to claim 1, wherein, at each front link arm, the first pivot axis is arranged generally between a respective rotational axis of a front caster wheel and the drive wheel. 8. The wheelchair according to claim 1, wherein, for each rear link arm, the second pivot axis is arranged generally between the coupling of the rearward portion and the forward portion and a rotational axis of a rear caster wheel. 9. The wheelchair according to claim 1, wherein the rear link arms are formed of vertically arranged plate shaped material. 10. The wheelchair according to claim 1, wherein the front link arms form spring leaves. 11. The wheelchair according to claim 10, wherein the rear link arms form spring leaves. 12. The wheelchair according to claim 7, wherein the rotational axis of the drive wheel is located generally above the first pivot axis and the second pivot axis. 13. A wheelchair comprising: a substantially horizontal seat having a front end and a rear end, a substantially vertical back rest proximal the rear end of the substantially horizontal seat, and a central chassis frame;a pair of front link arms proximal the front end of the wheelchair, each front link arm pivotally connected to the chassis frame at a respective first pivot axis, each front link arm having a portion extending forward of the first pivot axis and a rearward portion extending rearward of the first pivot axis;a pair of rear link arms proximal the rear end of the wheelchair, each rear link arm pivotally connected to the chassis frame at a respective second pivot axis rearward of the first pivot axis, each rear link arm having a portion extending rearward of the second pivot axis and a forward portion extending forward of the second pivot axis to overlap, at least in part, with the rearward portion of the corresponding front link arm;a pair of drive assemblies, each drive assembly non-pivotally and fixedly mounted to an adjacent one of the pair of front link arms; andthe rearward portion of each front link arm comprising a slot and the forward portion of the adjacent rear link arm comprising a stud operatively engaged to move in the slot to allow relative movement between each front link arm and the adjacent rear link arm such that when the front link arm pivots about the first pivot axis in a first direction, the rear link arm pivots about the second pivot axis in a second direction opposite the first direction. 14. The wheelchair of claim 13, wherein the first and second pivot axis are arranged generally below a respective rotational axis of the drive assemblies. 15. The wheelchair of claim 13, wherein pivoting the pair of front link arms in a counter clockwise direction lifts the horizontal seat. 16. The wheelchair according to claim 15, wherein pivoting the pair of front link arms in a counter clockwise direction provides a downward force on the drive assemblies. 17. A wheelchair comprising: a substantially horizontal seat having a front end and a rear end, a substantially vertical back rest proximal the rear end of the substantially horizontal seat, and a central chassis frame;a pair of front link arms proximal the front end of the wheelchair, each front link arm pivotally connected to the chassis frame at a respective first pivot axis, each front link arm having a portion extending forward of the first pivot axis and a rearward portion extending rearward of the first pivot axis;a pair of rear link arms proximal the rear end of the wheelchair, each rear link arm pivotally connected to the chassis frame at a respective second pivot axis rearward of the first pivot axis, each rear link arm having a portion extending rearward of the second pivot axis and a forward portion extending forward of the second pivot axis to overlap, at least in part, with the rearward portion of the corresponding front link arm;a pair of drive assemblies comprising a drive wheel, each drive assembly non-pivotally and fixedly mounted to at least one of the chassis frame or an adjacent one of the pair of front link arms; andthe rearward portion of each front link arm comprising a stud and the forward portion of the adjacent rear link arm comprising a slot, the stud operatively engaged to move in the slot to allow relative movement between each front link arm and the adjacent rear link arm such that when the front link arm pivots about the first pivot axis in a first direction, the rear link arm pivots about the second pivot axis in a second direction opposite the first direction. 18. The wheelchair according to claim 17, wherein, at each front link arm, the first pivot axis is arranged generally between a respective rotational axis of a front caster wheel and a drive wheel. 19. The wheelchair according to claim 17, wherein, for each rear link arm, the second pivot axis is arranged generally between the slot and a rotational axis of a rear caster wheel.