Apparatus For Specific Lumbar Traction Treatments

Abstract

An apparatus for selectively and specifically exerting either continuous or intermittent traction and complementary treatments to the lumbar spine region of a patient accomodated on a platform system and having pelvic and thoracic belts secured to traction and counter traction applying bars. The platform system includes a thoracic platform supported for selective lateral tilting adjustment, a lumbar support the upward projection of it can be selectively adjusted and a pelvic and leg platform supported for lengthwise displacement. The apparatus comprises also a mechanism for applying either continuous or intermittent motion to one bar to apply the traction with a selectively adjusted maximal tractive force. Further, the apparatus is preferably complemented with an anti-scoliosis unit wherein a selectively positionable and rotatable leg supporting platform is provided for positioning the patient for specific anti-scoliosis treatments.

Description

BACKGROUND OF THE INVENTION

This invention is generally concerned with apparatuses for mechanically exerting treatments of the lumbar spine region, broadly comprising applying a traction to the lumbar spine and neighbouring region of a patient. Specifically, the invention has for its principal object to provide a new and improved apparatus adapted for selectively exerting tractions and actions in any selected mode and conditions well adapted to fit most differing requirements selected in view of the many several physical malfunctions, diseases and disabilities of individual patients, as well as to fit to the own physical fitness and condition of different patients, such as age, body structure and so on. Therefore, from another standpoint of view, the present invention provides a substantial improvement to heretofore proposed devices for mechanically applying either continuous or intermittent traction to the lumbar spine region of a patient, by providing a new and advantageous apparatus such designed that an exceedingly wide variety of selective adjustments, arrangements and combinations can be readily provided to meet the most wide range of patient's parameters and disabilities' variables.

It is known to physicians and those skilled in the art to which this invention appertains that a large plurality of disabilities can effect the lumbar spine region. For better understanding of the invention, such disabilities comprise, inter alia, slipped, compressed and prolapsed discs, lumbar, lower thoracic, ilium, sacro-iliac and pelvic subluxations, anteriorly and posteriorly rocked pelvis, lordosis and kyphosis of lumbar spine, lumbar vertebral rotation, lumbar and lower thoracic scoliosis, spondylolysthesis of fifth lumbar vertebra, pelvic inclination, compression of nerve root, and so on. The several variables include the actual tractive force or pull to be applied and the duration of individual treatments, and further any specific and properly exerted treatment of different individual disability will require an its own mode of applying the proper force. Typically, the direction and/or the amplitude of the vertebral rotations, scoliosis and so on will require sharply different specific treatments, for example.

Further, such different treatments are to be applied so that no undesirable counter-actions will result, that the patient will not suffer unduly pain, and so on, these and other requirements being met only upon careful selection of the manner of positioning, accommodating and adjusting the components by which the also preselected forces are to be applied, to the patient.

It is therefore a particular object of the invention to provide a new and advantageous apparatus including a new arrangement and combination of and complemented with stationary and selectively movable parts, mechanisms and driving and driven components, for selectively adapting same apparatus for exerting actions adjusted both to individual patients and to individual treatments. The most wide wariety of such action comprises, inter alia, exercising a deep-massage like action on muscular and ligamentous strudtures for restoring an even elasticity and tone; increasing the intervertebral spaces; facilitating the re-orientation of the intervertebral disc; relieving muscle spasm and hypertonia; increasing the blood supply in the area of the eschemic nerve roots; reducing inflammation and swelling; restoring adequate space for the passage of spinal nerves through the neural canals and intervertebral foramina, relieving compression; preventing the formation of adhesions between dural sleeve of the nerve root and adjacent structures; freeing existing adhesions; realigning forward and backward sliding of disoriented articular surface; improving and compensating some of the above said disabilities such as hyperlordosis, kyphosis and scoliosis, and increasing range of motion in all planes; mobilizing fixations by reducing vertebral rotation, and so on.

BRIEF SUMMARY OF THE INVENTION

In its broad aspect, an apparatus improved according to the invention comprises a supporting stationary structure having a platform system for patient's accommodation thereon, such system including a thoracic platform and a pelvic and leg platform, positioned for supporting the thoracic and respectively the pelvic and leg regions of the patient, the said platforms being supported for selective relative lateral inclination about the symmetry axis of said platform system at either sides of a mean position wherein said platforms are co-planar; such structure has a head end and a foot end, either comprising means for adjustably connecting adjustable counter traction and respectively traction straps having thoracic halter and respectively pelvic halter means secured thereto, the connecting means adjacent to said foot comrising a selectively inclinable cross bar and means for selectively connecting said straps a different distance from said symmetry axis; and a mechanism for selectively applying an either continuous or intermittent force of selectively adjustable maximal value to said cross bar in a direction parallel to said axis, tending to further spacing said bar from said foot end, whereby applying to said pelvic halter means and thus to the lumbar region of the patient a traction counter-acted upon by the resistance applied by the said thoracic halter means, counter traction straps and connecting means adjacent to the head end of the apparatus.

According to advantageous features of the invention, said thoracic and pelvic and leg platforms are spacedly supported on said structure, and a lumbar support member is located in the spacing between said platforms, and supported for selectively adjusting the height at which said lumbar support projects above the plane defined by said platform system. Preferably, such lumbar support comprises an essentially cylindrical upper surface the axis of which is horizontal and transversal, and designed for contact with the lumbar region of the patient, and is supported for rotation about said tranversal axis for frictionless support of the patient when displaced along the platform system when subjected to the traction.

According to another advantageous feature of the invention, the said pelvic and leg platform is movably supported on said structure for movement in the direction defined by said symmetry axis, also for frictionless support of the pelvic and leg regions of the patient when subjected to the traction.

According to a further advantageous feature of the invention, the apparatus is complemented by a specifically anti-scoliosis treatment unit, comprising an adjustably articulated and rotatable support structure designed for adjustably positioning a complemental leg support minor platform above the said pelvic and leg platform at its portion nearer to said thoracic platform, said minor platform being rotatable about a vertical axis and connected to means for selectively imparting rotations about said latter axis.

The said force applying mechanism preferably comprises a spring system connected to transmission and adjusting means to apply a constant load thereto, said transmission means including lever and link means arranged to transmit said load to said cross-bar to bias said latter bar for displacing same from said foot end, and the said adjusting means comprise means for selectively modify the lever arm lengths in said transmission lever for selectively modify the ratio of the load applied by the spring system and the transmitted load actually applied to bias said cross-bar and therefore to the pelvic halter means and thus to the patient's lumbar region.

The said mechanism comprises further motor, crank and link means connected to said transmission means for intermittently applying thereto a force greater than the maximal transmitted force, for intermittently overcoming the bias applied to said cross-bar, displacing the latter bar towards the patient and therefore intermittently discontinuing the traction applied to his lumbar region.

These and other features and advantages of the invention will be made more clearly apparent from a consideration of the following detailed description of a preferred embodiment of the invention, taken in conjunction with the accompanying drawings, forming an essential component of the present disclosure.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a diagrammatical perspective view, in small scale and having the most of details omitted, of the apparatus;

FIG. 1A is a similar view of the anti-scoliosis unit;

FIGS. 2, 3 and 4 are a plan view and respectively an end view (viewed at the foot end) and a side elevation of the apparatus, complemented with said anti-scoliosis unit;

FIG. 5 is a detailed view of the means for selective lateral inclination of the thoracic platform, taken in the plane indicated at V--V in FIGS. 2 and 4;

FIG. 5 is a fragmentary view of the lumbar support, in longitudinal section taken in the plane indicated at VI--VI in

FIG. 7, wherein same detail is shown in a cross-sectional view, taken in the plane indicated at VII--VII in FIGS. 2 and 4;

FIG. 8 is a fragmentary longitudinal sectional view, taken in the plane indicated at VIII--VIII in FIG. 3, and having components partly broken away, of the traction force applying mechanism, when such force is being discontinued;

FIG. 9 is a similar fragmentary view of same mechanism, when such force is being applied;

FIG. 10 is a further fragmentary view of the force adjusting device of said mechanism;

FIG. 11 is a fragmentary cross-sectional view illustrating the pelvic and leg supporting means, and

FIG. 12 is a longitudinal sectional fragmentray view taken in the plane indicated at XII--XII in FIG. 11.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT

Referring first to FIGS. 1 to 4 inclusive, the apparatus comprises a supporting stationary structure generally indicated at 14 and having vertical walls 16 defining an enclosure wherein the various mechanical components and devices are enclosed and suitably protected. Said structure supports a platform system at the most suitable level for the patients accommodation and examination and control by the physician. The platform system comprises a properly stuffed thoracic platform 18, longitudinally cut at 20 (FIG. 1) to form a nose and breathing opening made use of when the patient is face-down accommodated, and an also properly stuffed pelvic and leg platform 22. The said thoracic platform 18 is supported for selective lateral inclination and positioning in either directions indicated at A' and A"; the pelvic and leg platform 22 is supported for longitudinal displacement in direction B, for frictionlessly following the displacements of the pelvic and leg regions of the patient, when subjected to a traction in direction T, while his head and thoracic regions are being held stationary by a properly applied counter-traction or reaction R.

The lateral inclination of thoracic platform 18 is critical of the invention and has been found as extremely important for properly preparing the patient for specific treatments of vertebral rotation, particularly for bringing the spinal column about in such a way that the lumbar vertebrae are counter-rotated, bringing the lumbar spine into a more ideal alignment for the application of the traction. This compensation for the lumbar rotation has been found tantamount to obtaining maximum results in traction treatment, and eliminates injurous side-effects.

The said platforms 18 and 22 are longitudinally spaced from each other and a stationary minor platform 24 is co-planarly supported therebetween. Such minor platform 24 is apertured for upward projection of a lumbar support 26, having a suitably stuffed upper surface of generally cylindrical configuration. Such lumbar support 26 is supported for selective adjustment of its level, that is of the height at which its apex projects above the horizontal plane generally defined by the surface of platform system, for specific adaptation to the individual patient's lumbar spine curve.

This lumbar support and its vertical adjustment (indicated at C'-C" in FIG. 6) have been found of importance for counter-acting the injurous side-effect of straightening and flattening of the patient's lumbar spine, when subjected to traction. Upon proper level adjustment of such lumbar support, the traction action will properly lengthen but not straighten the lumbar spine curve, while such injurous flattening would otherwise dissipate the said traction action beyond the lumbar zone.

FIGS. 2 and 4 diagrammatically illustrate the accommodation of a patient prepared for treatment. A properly padded counter traction thoracic halter belt 28 is secured about the thoracic region of the patient. Said halter belt is connected to one end of adjustable straps 30, the opposite ends of which are detachable connected to transverse spacer bar 32, connected at 34 to a vertically adjustable member supported by a brace 36 projecting from and secured to the head portion of the stationary supporting structure of the apparatus.

An also properly padded traction pelvic halter belt 38 (FIG. 2) is secured about the pelvic region of the patient. By means of adjustable traction straps 40, such pelvic halter belt is tractively connected to a traction cross-bar 42, connected at adjustable level to a traction motion and force applying horizontal rod 44. More particularly, the cross-bar 42 is oscillatably connected to the upper end portion of a vertical rod 46 clamped at adjustable height to the leftward portion of said rod 44. Means are provided for selectively laterally rotating said cross-bar 42, in either directions indicated at D' and D" in FIG. 3. Further, the said traction straps 40 are secured to same cross-bar 42 by means of sleeve buckles 48, which can be individually slided along said cross-bar 42 in either directions indicated at E' and E" in FIG. 2, and secured in any desired position along their respective half of cross-bar.

The direction at which the traction pull is applied to the pelvic halter belt and therefore to the lumbar region of the patient is actually defined by the direction of the traction straps 40, running from said halter belt to the sleeve buckles on said cross-bar 42. Now the actual level of said buckles 48 can be selectively adjusted by vertically adjusting said rod 46 and can be selectively differentiated by the inclination of said cross-bar (as indicated at D' and D"); further such directions can be individually adjusted in the horizontal plane by laterally spacing said buckles 48 along the cross-bar (as indicated at E' and E"). Such adjustments provide for proper preparation of the patient in view of different specific treatment, such as of rocked pelvis, for pelvic misalignments and so on.

The provision and use of the complementary anti-scoliosis unit can be understood from a consideration of FIGS. 1A, 2 and 3, and more particularly of FIG. 4. This unit is secured, preferably but not necessarily in detachable manner, to a column 50 (FIG. 3) fixedly secured to the stationary structure, and comprises a post 52 having a laterally projecting brace 52a. By means of a suitable mechanism, such as a rack, provided with an elevation means such as a control wheel 54, a vertical rod 56 can be vertically adjusted and positioned below said brace 52a. Said components are dimensioned to selectively place the device above the patient (FIGS. 3 and 4), or spaced away (FIG. 2) when the use thereof is not required.

Said vertically adjustable rod 56 has an amplitude of torsion selector head 58 secured at its lower end and forming a connection for rotation about a vertical axis of components secured therebelow. Such components comprise a leg support platform, generally indicated at 60, having a middle longitudinal vertical stuffed wing 62 and symmetrical lateral nearly horizontal stuffed leg supporting planar parts 64. FIG. 4 illustrated in dot-and-dash lines at S, a typical accommodation of a patient in view of an anti-scoliosis treatment. By means of a handle-bar 66, for example, the said platform 60 can be rotated in either directions, as indicated at F' and F" in FIG. 1A, and locked at any selectively desired position about its vertical axis. This rotation can be also be intermittent and a torque measuring device can be provided for controlling the selected maximal force applied. A suitable motor and mechanism assembly, easily conceivable by those skilled in the art, can be provided for selectively adjustable self-action of the anti-scoliosis unit, namely for intermittent rotation.

A wide variety of structures, devices and mechanisms can be devised for providing the above illustrated critical and important adjustments and selectivities for adapting the new apparatus to the above generally indicated very large variety of specific treatments of individual patients. In FIGS. 5 to 12 inclusive preferred examples of such structures, devices and mechanisms are illustrated.

FIG. 6 deals with the means for supporting, laterally inclining and maintaining in the selected position the thoracic platform 18. Such platform is supported by T-shaped members 180 pivotally supported at 182 for lateral inclination in either directons A' and A" (such as exemplified in the position indicated by phantom lines). The downwardly extending brace 184 of one of said members is longitudinally slotted for slidingly engage a pin secured to a screw-nut 186 engaged by a transversal horizontal screw-threaded rod 188. A handle 190, external to the wall 16 of the stationary structure 14 (see FIG. 4) is provided for operator controlled rotation of said rod 188 and therefore for inclining at will said platform 18, which is then maintained in the selected position by the irreversibility of the screw and screw-nut transmission. The degree of inclination can be visualized by an external scale 192 (see FIG. 4 also).

FIGS. 6 and 8 refer to supporting and adjusting of the lumbar support 26. Such support 26 has a stuffed layer secured to partly cylindrical member 260 rotatably supported about its axis by pivotal pins 262 on a structure 266 (FIG. 7). Springs 264 (FIG. 6) bias such member 260 towards its average position, the rotatability of the lumbar support in either directions, as indicated at G' and G" in FIG. 6, provides for frictionless supporting of the patient's lumbar region when subjected to motion resulting from the applied traction. Such member 266 is guidedly supported for vertical displacement (indicated at C'C") by means of vertical parallel guide rods 268 slidable within bushings provided in a structural component 270 of the stationary structure of the apparatus.

The said member 266 has a screw-nut 272 integrally formed therewith and which engages a vertical screw-threaded bar 274, rotatably but not axially supported by said structural component 270. By means of bevel gears 276, a shaft 278 and a handle 280 (see FIG. 4 also) the level of said lumbar support 26 can be adjusted at will. A scale 282 (FIG. 4) external to the wall 16 and an index moving concurrently with said member 266, and secured by example to one of guide rods 268, provide for indicating the height at which the lumbar support is adjusted and maintained by the irreversibility of the transmission provided by the screw-threaded bar 274.

FIGS. 8 to 10 inclusive illustrate a preferred mechanism for either continuously or intermittently applying an adjustable force in direction T for traction treatments. The said rod 44 is connected to a plate 400 secured to a member 402 longitudinally and guidedly supported by horizontal rods 404 secured to components of the stationary structure 14. A flexible but not extensible link means, such as a chain 406 connects said plate 400 and rod 44 to the crank pin 408 of a crank lever 410 connected to a shaft 412 driven by a motor (not shown) by means of a gearing (in a casing 414) and a transmission 416 .

The plate 400 has an idle roller 418 secured thereto. Such roller 418 is slidably engaged into a slotted part 420' of a two-armed lever oscillatably supported about a pivot 422 (FIGS. 9 and 10). Such pivot is secured to a slide member or block vertically displaceable along guide bars 426 and having a vertical screw-nut 424 integrally formed therewith. A vertical screw-threaded rod 428 is rotatably but not axially supported by another component of the stationary structure 14. Suitable motor and transmission means, generally indicated at 430 in FIG. 8, are drivingly connected to said screw-threaded rod 428 for operator controlledly actuating same in either directions and adjusting the level at which said block and pivot 422 can be set.

In the also lengthwise slotted other part 420" of the two-armed lever another idle roller 434 is slidably engaged, said idler roller being only horizontally displaceable as being guided by glide bars 436 (fragmentarily shown in FIGS. 8 and 9); another flexible but not extensible link, such as a chain 438, has one end connected to said second idle roller 434 and applies thereto a pull, in direction M, provided by the load of a tension spring 440. Such pull is made constant, irrespective of the actual elongation of spring 440 (within the required amplitude of elongation) by a compensating device, which for example comprises an idle wheel 442 having a camming part 444 to which it is secured one end of another chain 446 the other end of which is connected to said spring 440, the variable radius of such camming portion 444 (see FIG. 9) compensating the increasing biasing force of the spring as far as its elongation increases.

The continuous traction T can be applied to the patient by positioning and maintaining the crank 410 in the position illustrated in FIG. 9, that is turned towards the roller 418. The chain 406 is slacked and does not prevent a motion, in direction T, as necessary to apply the traction to the patient's lumbar region, by the means of components 440, 446, 438, 434, 420'-420", 418, 400, 44, 46, 42, 48, 40 and the pelvic halter 38. If the selected treatment includes the intermittent traction, the transmission 416, 414 is actuated for continuously rotating the crank 410 for cyclically applying a pull in direction T' to all components connected to plate 400 and therefore cyclically discontinuing the traction. It can be noted that either operating for continuous or intermittent traction, the force of the applied traction cannot be anyway greater than that applied by the spring 440 to said idle roller 418, by means of the mechanism including the said two-armed lever 420'-420", oscillatable about the axis of pivot 422.

This force can be however varied at operator control, within the desired range, by controlledly actuating the motor at 430 and therefore the vertical screw-threaded rod 428, as now explained with reference to FIG. 10. The force actually applied to rod 44, for actual traction T on the lumbar region of the patient, is related to the biasing force M actually exerted on chain 438 by the expression

T = I"/I' M wherein I' and I" are the intervals from the pivotal axis at 422 to the axis of driven roller 418 and respectively to the axis of driving roller 434. It is to be taken into account that such rollers are caused to be only horizontally displaced, as being carried by the assembly comprising plate 400 and member 402 which is slidable along horizontal rods 404, and respectively as being guided by the horizontal guide bars 436, and therefore that the level of the horizontal paths of such rollers cannot be modified as being defined by stationary structural components.

The pivotal axis at 422 of the two-armed lever can however by selectively adjusted by rotating said screw-threaded rod 428, that is by raising and lowering the block which carries the pivot 422 and which is slidable along vertical guide bars 428. The ratio I"/I' can be therefore be varied for proper selection of the force of traction either continuously or intermittently applied. For example by setting the mechanism as shown in FIG. 10, the force actually applied at T is about twice the actual biasing force applied at M.

FIGS. 11 and 12 illustrate a manner for supporting the pelvic and leg platform 22 for displacement in direction B, so that corresponding motions of the pelvic and leg regions of the patient, resulting from the traction, can be frictionlessy followed. Such platform 22 is guidedly supported by pairs (222 and 224) of idle rollers idly supported by pivots secured to plate members 220 appertaining to the planar structure of the platform 22, and rollingly embracing longitudinal, parallel and horizontal guide bars 226 secured to components of the stationary structure 14.

A spring 228 having one end secured to said stationary structure 14 and another end secured at 230 to the movable platform structure, biases said platform in direction B' for returning same in its rest position (as shown in FIGS. 4 and 12). This spring 228 is pretty weak so that such motions in direction B can be made painlessly for the patient. Suitable locking means (not shown) can be provided for locking such platform 22 at its rest position, for facilitating accommodating and removing of the patient, said locking means being obviously to be unlocked as the patient has been prepared for the traction treatment.

The apparatus is suitably complemented with control panels and boards including on-off and selector switches, safety devices, clock means for automatically discontinuing the actuation after a predetermined treatment time and so on. In FIG. 4 a control devices for adjusting the force applied for the traction has been generally illustrated at 432.

Claims

I claim:

1. An apparatus for mechanically, adjustingly and selectively exerting specific treatments including a traction applied to the lumbar region of a patient having a thoracic halter belt adapted to be and a pelvic halter belt secured about his body regions bordering his said lumbar region, the traction treatment comprising applying oppositely directed pulls on said halter belts, the said apparatus comprising, in combination: a stationary structure having head and foot ends and supporting at its upper surface an essentially horizontal patient supporting platform system having a longitudinal symmetry axis and comprising a thoracic platform, a pelvic and leg platform, and a lumbar support between said platforms and upwardly projecting above the plane generally defined by said platform systems, one of said platforms being selectively tiltable in either direction about said longitudinal axis, cross-bars arranged adjacently to said head and foot ends and adapted for connecting thereto straps secured to said thoracic and respectively pelvic halters and a mechanism for controlledly applying to one of said cross-bars a selectively adjustable force tending to increase the spacing between said cross-bars and therefore a preselected traction to said patient's lumbar region.

2. The apparatus of claim 1, wherein the said thoracic platform is supported for lateral tilting about said symmetry axis, is connected to an operator controlled mechanism including irreversible transmission means for selectively and adjustably lateral tilting of said platform and maintaining said platform at the inclination at which it has been set, and wherein the said traction force applying mechanism is drivingly connected to the cross-bar located adjacent to said foot end.

3. The apparatus of claim 2, wherein the said pelvic and leg platform is supported upon said stationary structure for lengthwise guided displacement for frictionlessly accommodating the motions of the patient's pelvic and leg regions when subjected to traction treatment, and wherein spring biasing means are provided for returning same pelvic and leg platform to its position nearest to said thoracic platform when the said traction treatment is discontinued.

4. The apparatus of claim 1, wherein the said lumbar support is supported upon said stationary structure for vertically guided displacement and is connected to an operator controlled mechanism including irreversible transmission means for selective adjustment of the height at which said lumbar support projects above the plane generally defined by adjacent platform and maintaining said lumbar support at the height at which it has been set.

5. The apparatus of claim 4, wherein said lumbar support comprises a lumbar supporting body having an upper lumbar curve supporting surface of cylindrical configuration about an axis horizontal and transversal, said body being supported for rotating about said axis for frictionlessly accommodating the lengthwise motions of the lumbar region of the patient when subjeced to traction treatment.

6. The apparatus of claim 1, which is complemented by an anti-scoliosis unit comprising a leg supporting platform having a vertical longitudinal symmetry plane and a longitudinally and upwardly extended middle portion defining the actual direction of the patient's legs when set on said platform, means for positioning and sustaining at adjustable height said platform above the pelvic portion of the said pelvic and leg platform, and means for operator controlledly rotating the said leg supporting platform about a vertical axis in its said vertical symmetry plane.

7. The apparatus of claim 2 wherein said traction applying cross-bar has opposite portions symmetrical to a middle point, is supported for operator adjustable lateral tilting about an axis parallel to and above the said longitudinal symmetry axis, and is vertically adjustably connected to said mechanisms, and wherein the straps secured to said pelvic halter belt are connected to buckle means individually and selectively positionable along the one and respectively the other of said cross-bar opposite portions.

8. The apparatus of claim 1, wherein the said force of traction applying mechanism comprises a driven assembly supported for reciprocation in the direction defined by said symmetry axis and having the said cross-bar adjacent to said apparatus foot end adjustably connected thereto, a driving assembly urged in a given direction by a source of force, of adjustably selected maximal value, a variable ratio transmission connecting said driving assembly to said driven assembly for applying to said driven assembly and cross-bar an actual traction treatment force corresponding to the force applied by said source by the ratio at which said transmission has been set upon operator contol, and means for controlledly cyclically applying to said driven assembly a counter force exceeding the actually applied force for cyclically urging said assembly and cross-bar in direction opposite to that in which the traction treatment is being applied for consequently providing for intermittent traction by discontinuing the application of said traction force.

9. The apparatus of claim 8, wherein said source of force comprises spring means connected to apply a load in a given direction, means for compensating the variation of said load as resulting by a variation of the elastic deformation of said spring means to provide an essentially constant given load and wherein said transmission comprises a lever oscillatably supported about a pivotal axis, means for drivingly applying said given load to a first point of said lever at a first interval from said pivotal axis, means for drivedly connecting said reciprocatable driven assembly to a second point of said lever at a second interval from said pivotal axis, and operator controlled means for selectively modifying the length ratio of said first interval by said second interval.

10. The apparatus of claim 8, wherein the said counter force applying means comprise a motor operated crank means having a crank pin adapted for operator activated continuous revolution, and a flexible and not extensible link connecting said crank pin to said reciprocatable driven assembly, said crank and link means being arranged and dimensioned for undisturbing the stroke of said reciprocatable assembly and cross-bar in the traction applying direction under said force, when said crank pin is turned or maintained at its position near to said assembly, while when said crank pin travels along or is maintained in the arc of its revolution, far from said assembly, said link imparts to said assembly a counter stroke of amplitude such to minimize the traction applied to the patient's lumbar region.