Patent GB-1443891-A (GB)
Title: Lumbar traction apparatus
IPC: A61F5/02
Filed: 1974-01-25
Abstract: 1443891 Orthopaedic traction apparatus MEDITRAC 25 Jan 1974 [29 Jan 1973] 3537/74 Heading A5R Lumbar traction apparatus 10 comprises upper and lower U-shaped supports 11, 12 attached to the waist of a patient 13 by belt assemblies 14, a pair of laterally spaced traction control assemblies 15 extending between the supports 11, 12 with each assembly 15 comprising an in-use vertically extending tube 122 connected to the lower support 12 by a clamp 23 and a toothed rod 24 connected to the upper support 11 and telescopically mounted in tube 122, a pinion 28 carried on a rotatable shaft 26 mounted in a housing 27 and driven by a ratchet drive mechanism 16 associated with each assembly 15, the pinion 28 engaging the teeth on rod 24 to move rod 24 relative to tube 122 thereby moving supports 11, 12 apart and applying traction to the patient. Each belt assembly 14 comprises a strap 18, one end of which is attached to an end of a support 11 or 12 by a buckle and buckle catch plate (not shown), the other end of the strap being wrapped around a rotatable shaft carried on the other end of the support, a ratchet drive mechanism 21 being provided to rotate the shaft in one direction only and thereby tighten strap 18 and hence the supports 11, 12 to the patient. Each ratchet drive mechanism 16 comprises a ratchet wheel 40 selectively coupleable to shaft 26 by notches 47, 48, in the end faces of wheel 40 and in an enlarged head 45 of shaft 26, engaging a central rib 65 of a coupler 61 when the wheel and shaft have a predetermined angular position, the coupler 61 being carried on the end of a rod 60 coaxially mounted and axially movable within shaft 26 and urged into engagement with the notches 47, 48 by a compression spring 62 carried in a counterbore 63 of shaft 26, axial movement of shaft 26 relative to housing 27 being prevented by a counterbored plug 43 mounted in a hole 42 of housing 27 engaging the other end of shaft 26, coupler 61 being removed from notches 47, 48 by gripping and pulling on a knurled grip 64. To aid removal of coupler 61 from the notches 47, 48 a forked lever (not shown) engageable under, the enlarged head of coupler 61 is pivoted to move coupler 61 out of engagement. The ratchet wheel 40 is rotated by a ratchet wheel operator 41 comprising a pair of plates 49, 50 having circular holes 51 rotatably receiving the hub of ratchet wheel 40 on each side of its toothed periphery, and a connector portion 53 joining the plates 59, 50 and forming an operating handle, a drive pawl 54 mounted between the plates being urged by a spring 55 into the teeth of wheel 40 so that oscillatory motion of the handle produces uni-directional rotation of wheel 40, with a stop pawl 56 preventing reverse rotation. Ratchet drive mechanism 21 is of similar construction to the mechanisms 16. Each rod 24 is resiliently carried on the upper support 11 in a bore of a connector member 25 and retained by means of a pin mounted in the member 25 engaging a circumferential groove in rod 24, relative axial movement of the rod and the support being damped by a compression spring. A lordosis pad assembly 17 is also provided for controlling the forward convexity of the spine, the assembly 17 comprising a bifurcated upwardly extending bracket attached to the central portion of lower support 12, and a threaded nut frictionally engaging and slidable within the slot in the bracket and carrying a threaded shaft having at its inner end a ball-jointed padded disc for contacting the patient's back, and at its outer end a handwheel for rotating the shaft. A gauge 57 records the amount of traction applied to the patient.