National Research Development Corporation

The Secretary of State for Social Services in Her Britannic Majesty's

John D Harris

Mervyn Evans

Graham E Mead

Michael F Fogden

A non-rigid bone fracture fixator comprising first and second bone pins for connection either side of a bone fracture and primary and secondary supports clamped to the bone pins by respective fixed and guide clamps. The second support and the guide clamps are connected slidably to the primary support such that the supports may execute a controlled degree of movement with respect to one another. A compression spring is arranged to bias apart the supports longitudinally of a fixated limb. In use the fixator is applied to the limb with the fracture in slight compression. Exercise of the limb then produces varying degrees of fracture compression stimulating bone callus formation and rapid healing. The fixator may include actuating means to provide passive fracture exercise for immobilized patients.

Apparatus for external fixation of bone fractures

A post-fracture bone immobilization splint for unilateral fixation comprises a rigid bar on which are slidably mounted at least four pin clamps. Each pin clamp is fixable to the bar and is provided with a pin to engage a part of the fractured bone. The pin is supported in two holes diametrically located in a hollow cylindrical portion of the pin clamp, the diameter of the holes being larger than the pin diameter such that the pin can be adjusted slidingly as well as azimuthally within a limited range of zenith angles. The annular gap surrounding the pin is sealed by surrounding moveable washers which are spaced apart within cylindrical portion by a plastic tube through which the pin passes. The remainder of the hollow portion is filled with small ball bearings that are compressible by a threaded plug. The pin is positioned as desired and the threaded plug is then rotated to compress the ball bearings which deform the plastic tube and thereby grip the pin. Under greater compressive force, the ball bearings will penetrate the plastic tube and deformably engage the pin.

Post-fracture stability of limbs

A reel for use upon a cylindrical support on plaster jacket bedframes incorates a ratchetless anti-reverse mechanism which is readily disengageable and which permits continuous adjustment of the position of the reel upon the bedframe. The anti-reverse mechanism comprises a close wound helical spring which has a free diameter less than the diameter of the cylindrical support. The spring is mounted on the cylindrical support and attached by one of its ends to a spool rotatably mounted on the cylindrical support.

Reels for medical traction applications

A power assisted wheelchair has a pair of larger ground wheels with handwheels mounted thereon and a pair of smaller castor wheels carrying motors drivably coupled therewith. The handwheels are rotatable relative to their ground wheels against a spring bias and operate the castor wheel motors on the corresponding sides of the chair through respective switch mechanisms. Variations of this arrangement are possible to suit different ground wheel configurations, the motors can be energized in increasing manner, the motors can be disconnected when the castors turn rearwardly, and the motors can drive through freewheel mechanisms.

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Abingdon, United Kingdom

John D Harris