Portable cervical traction device

A portable traction device suitable for cervical traction powered by a pneumatic cylinder. The portable traction device includes a support structure having a longitudinal axis and a carriage slidable along a portion of the support structure parallel to the longitudinal axis. The carriage including restraining mechanism for releasably restraining a portion of a patient's body to the carriage. A pneumatic cylinder includes a cylinder housing attached to the support structure. The cylinder housing contains a piston and piston rod. The piston rod is attached to the carriage for moving the carriage along the longitudinal axis relative to the support structure when pressurized air is injected into the pneumatic cylinder. The piston has at least one pressure activated seal extending circumferentially around the piston for engagement with an inside surface of the cylinder housing. A bicycle-style hand pump fluidly connected to the pneumatic cylinder is provided for injecting pressurized air into the cylinder.

FIELD OF THE INVENTION

The present invention is directed to a portable traction device powered by a pneumatic cylinder.

BACKGROUND OF THE INVENTION

Traction is widely used to relieve pressure on inflamed or enlarged nerves. While traction is applicable to any part of the body, cervical and lumbar or spinal traction are the most common. When correctly performed, spinal traction can cause distraction or separation of the vertebral bodies, a combination of distraction and gliding of the facet joints, tensing of the ligamentous structures of the spinal segment, widening of the intervertebral foramen, straightening of spinal curvature and stretching of the spinal musculature. Depending on the injury being treated, the traction component of physical therapy may require multiple sessions per week for a prolonged period of time.

Cervical traction requires a traction force up to approximately 222 N (50 lbs.). Lumbar traction typically requires force equal to half of the patient's bodyweight, or about 333-667 N (75-150 lbs.). The equipment necessary for performing traction, however, has typically been expensive and thus only available to a patient in a therapist's office.

Attempts to create a sufficiently low cost portable traction device for home use have thus far produced unsatisfactory results. A number of portable traction devices utilize pneumatic or hydraulic cylinders to create the traction force. Hydraulic cylinders have the disadvantage of the weight of the hydraulic fluid. Pneumatic cylinders with low pressure inputs typically can not maintain an adequate traction force for a sufficient period of time to be effective in a traction device. In an attempt to overcome this deficiency, some of these devices utilize an automatic pumping device triggered by a pressure sensing device to supply additional compressed air so that a constant level of traction force is maintained. These pump and sensor configurations add cost, weight and complexity to the traction device.

The air input pumps used on some traction devices also exhibit a number of shortcomings. For example, bulb-type air pumps produce relatively small input pressures. A small female patient can generate only about 483 kPa (7 psi) of pressure using a bulb-type pump. Consequently, small input pressure devices require large diameter cylinders to generate the necessary output traction forces. Larger diameter cylinders, when used with low pressure input devices, are more prone to leak, thereby further complicating the problem of maintaining a constant traction force for a prolonged period of time.

Therefore, what is needed is a low cost, light weight portable traction device utilizing a pneumatic cylinder which can maintain a traction force of an adequate magnitude for a prolonged period of time.

SUMMARY OF THE INVENTION

The present invention is directed to a portable traction device powered by a pneumatic cylinder. The present invention is also directed to a pneumatic cylinder suitable for use in traction devices.

The portable traction device includes a support structure having a longitudinal axis and a carriage slidable along a portion of the support structure parallel to the longitudinal axis. The carriage including restraining mechanism for releasably restraining a portion of a patient's body to the carriage. A pneumatic cylinder includes a cylinder housing attached to the support structure. The cylinder housing contains a piston and piston rod. The piston rod is attached to the carriage for moving the carriage along the longitudinal axis relative to the support structure when pressurized air is injected into the pneumatic cylinder. The piston has at least one pressure activated seal extending circumferentially around the piston for engagement with an inside surface of the cylinder housing. A bicycle-style hand pump fluidly connected to the pneumatic cylinder is provided for injecting pressurized air into the cylinder.

In one embodiment, the portable traction device is configured for use as a portable, cervical traction device. The carriage may include a head support pad to receive a patient's head and a pair of opposing neck supports contoured and arranged to engage the occipital area of the patient's head when the head is on the head support pad. The neck supports are adjustably attached to the carriage to permit adjustment of the lateral separation therebetween. A head support strap may be provided for restraining the patient's head to the support pad.

In an alternate embodiment, the portable traction device is configured as a portable, lumbar traction device. The restraining mechanism may include a waist belt for releasably restraining the lower body of the user to the carriage. The support structure preferably includes counter traction restraining mechanism for restraining the upper body of the user to the support structure. Alternatively, the restraining mechanism includes a pair of opposing, laterally adjustable hip gripping supports arranged to engage the superior edge of the user's pelvis.

The piston has a diameter smaller than an internal diameter of the cylinder housing so that a gap is formed therebetween. The pressure activated seal may be a pair of pressure activated seals arranged circumferentially around the piston. The pressure activated seal is a generally V-shaped seal member arranged to expand when the air pressure in the pneumatic cylinder exceeds 13.8 kPa (2 psi). In one embodiment, the pressure activated seal maintains a generally static traction force of greater than 111 N (25 pounds) for a period in excess of 10 minutes without additional pressurized air being injected into the cylinder. In an alternate embodiment, the pressure activated seal maintains a generally static traction force of greater than 200 N (45 pounds) for a period in excess of 20 minutes without additional pressurized air being injected into the cylinder.

The hand pump preferably includes a gauge indicating traction force and a pressure relief mechanism to manually release pressure in the pneumatic cylinder. In one embodiment, the operator rotates the gauge relative to the hand pump to release pressure from the cylinder. The cylinder preferably includes a pressure regulator to prevent the pressure in the pneumatic cylinder from exceeding a predetermined value. Alternatively, the pressure regulator may be located on the hand pump. The hand pump is capable of injecting at least 207 kPa (30 psi) of pressure to the pneumatic cylinder.

The present invention is also directed to the pneumatic cylinder and hand pump discussed above for use as the traction force generating apparatus on a portable traction device.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT

FIGS. 1 and 2illustrate an exemplary portable, cervical traction device20in which a carriage22and slide portion24are allowed to move freely on a track26along a direction “S” (see also FIG.3). The slide portion24includes a slide bracket28which engages with a piston rod30on a pneumatic cylinder32mounted underneath the track26. A lateral adjustment mechanism38, a head support pad76, and a pair of V-shaped neck supports50,52(see FIG.3), are mounted to the carriage22, which will be discussed in detail below. The pneumatic cylinder32is attached to the track26by an angle bracket34. An air line40is attached to an air inlet42at one end of cylinder32for providing pressurized air to the cylinder32. An alternate V-shaped neck support structure suitable for use in the present invention is disclosed in U.S. Pat. No. Re. 32,791 issued to Saunders on Nov. 29, 1988, which is hereby incorporated by reference.

The angle bracket34also serves the purpose of retaining the track26at an angle α relative to a support surface36. A removable stabilizer bracket35may optionally be added to prevent the angle bracket34from lifting off of the support surface36during use. A pad37preferably is placed over the angle bracket34for the comfort of the user. It will be understood that the length of the angle bracket34may be adjustable depending on the application of the portable traction device20. For example, the angle bracket34may be of a telescoping constructions. It will also be understood that the slide portion24may engage with the track26in a variety of configurations, and that the present invention is not limited to the specific embodiment disclosed herein. The track26, carriage22, and slide portions24are preferably constructed of a lightweight, low cost material, such as, for example, aluminum, steel, high density plastic, or a variety of composite materials.

FIG. 3is an end view of the lateral adjustment mechanism38on the carriage22. Left and right neck supports50,52form a V-shaped neck support structure that generally follows the contour of the base of the user's skull. The neck supports50,52are attached to a pair of corresponding lateral slides54,56on the carriage22. The lateral slides54,56are engaged with the threaded shaft58by a pair of coupler nuts60,62. The portion of the shaft58proximate coupler nut60has left-hand threads and the portion proximate coupler nut62has right-hand threads. The lateral position of the V-shaped neck supports50,52is adjusted by turning the left and right knobs70,72. The neck supports50,52are ideally positioned around the patient's head so that they contact and follow the contour of the occipital bone at the base of the patient's skull, while the back of the patient's skull rests on the head support pad.

FIG. 4illustrates a patient78utilizing the portable traction device20on a support surface36. It will be understood that the present portable traction device20may be used on a variety of support surfaces, such as for example, a floor, a table, or any other suitable surface. It will also be understood that the support surface36does not necessarily have to be horizontal and that it may be desirable to have an angled support surface for some types of traction. A support strap77may optionally be used to restrain the patient's head to the head support pad76during traction.

FIG. 5is a schematic illustration of a single-acting pneumatic cylinder32for use with a present portable traction device. Piston80has a diameter “P” which is slightly smaller than the inside diameter “C” of the cylinder32so that a small gap82is formed between the piston80and inner surface84of cylinder wall86. A pair of slots88,90extending around the outside perimeter of the piston80contain a pair of pressure activated seals92,94. The seals92,94are pre-shaped to form seal cavities98,100facing upstream of the piston rod30. It will be understood that the seals92,94and seal cavities98,100may be a variety of shapes.

The seals92,94are arranged so that as pressurized air91enters the air inlet42, and input chamber96is pressurized, a seal cavities98,100are pressurized and the pressure activated seals92,94are forced into engagement with the inside surface84of the cylinder wall86. In the exemplary embodiment disclosed herein, approximately 13.8 kPa (2 psi) is required to engage the seals92,94with the inside surface84. Seal94is intended to capture blow-by air that passes the first seal92. The small gap82between the cylinder wall86and the piston80permits generally uniform circumferential pressurization of the seals92,94against the inside surface84around the entire circumference, thereby enhancing sealing capabilities. The pressure activated seal of the present pneumatic cylinder32is capable of maintaining a static traction force of greater than 111 N (25 lbs.) for a period in excess of 10 minutes, and preferably, a static tract on force of greater than 200 N (45 lbs.) for a period in excess of 20 minutes, without the need to supply additional pressurized air.

When the pressure in input chamber96is released, the seals92,94disengage from the inside surface84and the piston80is allowed to move freely within the cylinder32. The pneumatic cylinder32may include spring or other resilient compression member102around the piston rod30to urge the piston80back toward the air inlet42when the compressed air91is released. Alternatively, a spring (not shown) may be positioned between the slide portion24and the track26. The compression member102preferably has a low spring forces so as to minimize the amount of force needed for the patient to activate the cylinder.

FIGS. 6 and 7illustrate an exemplary air pump120for use with the present portable traction device20. The air pump120has a T-handle122attached at one end by a pivot point124. The T-handle122configuration offers ergonomic advantages over a standard straight pump handle. Alternatively, a straight handle may be substituted for the T-handle. An adjustable pressure regulator126may optionally be included in the pump120or cylinder32(seeFIG. 1) so that over-pressure situations can be prevented. The other end of the air pump120includes a gauge128, which preferably is calibrated to read the actual amount of traction force being provided to the patient, rather than pounds per square inch. The pump, handle and gauge may be formed as a singled piece by an injection molding process.

A manual pressure relief mechanism130is also located proximate the gauge128for relieving the pressure in the pneumatic cylinder32when the treatment period is completed. Alternatively, the pressure relief mechanism (not shown) may be operated by rotating the gauge128. Air tube40is connected to the air pump120opposite the gauge128. A variety of pressure regulator configurations may be used in the present invention. For example, the pressure gauge128may include an internal pressure regulator.

To use the portable, cervical traction device20, it is placed on a suitable support surface36. The left and right knobs70,72are rotated to allow the neck of the user to fit easily between the left and right neck supports50,52. The slide portion24is moved down on the track26as far as possible by depressing pressure relief mechanism130(seeFIG. 7) until cylinder32is at atmospheric pressure.

The back of the user is placed on the support surface36so that the neck is cradled by the neck supports50,52. The neck supports50,52should initially contact the user in the mid cervical region, midway between the tip of the earlobe and the top of the shoulder. The knobs70,72are turned until the neck supports50,52are moved firmly against both sides of the neck. The user's head is secured to the head support pad76by the support strap77. With the head support pad76under the shoulders, the user's head should be nearly aligned with the spine.

The user then slowly pumps air into the cylinder32using the air pump120. The configuration of the pump120permits a patient to simultaneously view the gauge128and operate the pump, while inclined in the portable traction device20. The gauge128allows the user to stay within the pressure/traction force guidelines provided by the health care provider. The patient increases the traction force by manually operating the pump120or decreases the traction force by manually pressing the pressure relief mechanism130. The neck supports50,52are properly positioned when there is solid contact at the base of the head and the supports50,52are positioned near the tip of the ear lobes. When the treatment is complete, the traction force is released by pressing and holding the pressure relief mechanism130on the air pump120.

FIG. 8illustrates a portable, lumbar traction device140in which the pneumatic cylinder32is attached to a portable traction device140. The portable, lumbar traction device140includes a frame150retaining a support surface152. In a first embodiment, a pelvic belt142retains the patient's pelvis to a sliding portion154, which slides along track156. The pneumatic cylinder32mounted to the frame150is coupled to the sliding portion154so that the sliding portion154moves along the track156, creating a traction force “F” when the cylinder32is pressurized. A counter traction belt148provides a passive counter traction force on the patient's lower rib cage. The pneumatic cylinder32preferably maintains a static traction force of greater than 445 N (100 lbs.) for a period in excess of 10 minutes, and preferably, a static traction force of greater than 890 N (200 lbs.) for a period in excess of 20 minutes, without the need to supply additional pressurized air. It will be understood that two cylinders may be necessary to achieve a static traction force in excess of 445 N.

In a second embodiment, pelvic belt142is engaged with the pneumatic cylinder32by a cable144and pulley146configuration mounted at the foot of the portable traction device140. Counter-traction belt148provides a passive counter traction force on the patient's lower rib cage to restrain the patient in a fixed position relative to the portable traction device140. When the patient activates the pneumatic cylinder32as discussed above, the cable144is retracted, creating a traction force “F” on the waist belt142and the patient's pelvic region. In either of the above embodiments, the counter traction belt148may also be coupled to the pneumatic cylinder32to provide an active counter traction force in a direction opposite to “F” on the patient.

FIGS. 9a-9cillustrate an alternate embodiment of a portable, lumbar traction device200positioned directly on the support surface36. Upper body support platform202includes a frame204supporting a support surface206. A moveable head rest208is positioned on the surface206. Lower body support platform210has a support surface214slidably engaged with frame212. The surface214on the lower body support platform210slides in a direction “M” preferably about 0.15 meters under the force of a pair of pneumatic cylinders32′ (see FIG.10). The upper and lower body support platforms202,210are connected by a hinge215to facilitate shipping and storage of the lumbar traction device200.

An adjustable rib gripping belt216is attached to the upper body support platform202to provide a passive counter traction force in a direction “C”. A pair of laterally adjustable hip gripping supports218,220are connected to the surface214so that they move in the direction “M” with the surface214. The hip gripping supports218,220are independently adjustable and curved to generally correspond to the shape of the user's waist, as will be discussed in connection with FIG.11.

FIG. 10illustrates a segment of the frame212of the lower body support platform210. The piston rods30′ of the pneumatic cylinders32′ are engaged with the frame210. Cylinder heads31′ are attached to sliding support structure222that supports surface214. Introduction of pressurized air through the air inlet42′ moves the sliding support structure222and support surface214in the direction “M”. The operation of the cylinders32′ is substantially as discussed above in connection withFIGS. 5-7. The pair of cylinders32′ maintain a static traction force of at least 890 N (200 lbs.) for a period in excess of 20 minutes, without the need to supply additional pressurized air.

FIG. 11illustrates a hip gripping device230for use with the portable, lumbar traction devices20′ and200of the present invention. The hip gripping supports218,220are shown in both the maximum and minimum lateral positions. In the exemplary embodiment illustrated inFIG. 11, the maximum and minimum lateral positions correspond to a distance of 0.50 m and 0.29 m, respectively. However, it will be understood that the hip gripping device may be modified to accommodate larger and smaller users.

The hip gripping supports218,220include rigid curved members234,236covered with padding material232for the comfort of the user. The curves generally follow the contour of the waist of the human body. Suitable padding material include high density foam, rubber or a variety of elastomeric materials. The rigid curved members234,236include a pin238positioned to engage with receiving slots244on the top of the track242and a pin240positioned to engage with the bottom surface241of the track242. To adjust the hip gripping device230, the user rotates one or both of the hip gripping supports218,220in the direction “R” so that the pin238disengages from the slots244. While in the rotated position, the hip gripping supports218,220may be moved laterally along the track242to the desired location. Rotating the hip gripping supports218,200in the direction opposite to “R” will engage the pin230with one of the slots244. The hip gripping supports218,220may be completely disengaged from the track242by moving the pin240past the ends246of the track242near the cylinders32′ and lifting the supports218,220upward. It will be understood that the waist belt142ofFIG. 8may be substituted for the hip gripping device230.

To use the portable, lumbar traction device200, it is placed on a suitable support surface36. The hip gripping supports218,220are positioned to firmly, but comfortably, engage the waist of the user. The support surface214of the lower body support platform210is moved upward toward the upper body support platform202as far as possible by depressing the pressure relief mechanism130(seeFIG. 7) until cylinders32′ are at atmospheric pressure.

The back of the user is placed on the support surface206so that the waist is cradled by the hip gripping supports218,220. The hip gripping supports should initially contact the user midway between the bottom of the rib cage and the top of the pelvis. The user's chest is secured to the support surface206of the upper body support platform202by the rib gripping belt216. The head rest208should be placed under the user's head. The user then slowly pumps air into the cylinders32′ using the air pump120, as discussed in connection with the portable, cervical traction device20. The hip gripping supports218,220are properly positioned when there is solid contact with the top of the pelvis.

The present invention has now been described with reference to the several embodiments thereof. It will be apparent to those skilled in the art that many changes can be made in the embodiments described without departing from the scope of the invention. Thus, the scope of the present invention should not be limited to the structures described herein, but only by structures described by the language of the claims and the equivalents of those structures. For example, the present portable traction device may be arranged in a variety of configurations to facilitate traction to any part of the body.