Adjustable traction device

Abstract

A traction device comprises a base portion for mounting to the frame of a hospital bed. An upright support is swingably secured to the base portion and extends above the level of the bed. Flexible cable means are provided on the support for attachment to the patient. The vertical positioning of the flexible cable is adjustable on the support without changing the effective length of the cable. The swingable support may be moved in a direction away from the patient but, ordinarily, not toward the patient. However, control means are provided for overriding this condition and for automatically doing so whenever movement of the bed frame brings the support into engagement therewith.

Description

The invention relates to traction devices and, more particularly, to a traction device adapted to be mounted on a movable part of a hospital bed frame and adjustable relative to a patient on the bed so as to maintain proper traction on the patient when the bed is moved through its various positions.

In brief, the invention comprises a base mounted to a hospital bed and having an upright support extending above the level of the bed swingably secured to the base portion whereby said support may be moved away from a patient in the bed. Flexible cable means are secured to said support for attachment to a patient in the bed and the vertical position of said cable means is adjustable relative to said support. Means are provided for applying a force to said cable means to place the patient in traction.

In the drawings:

FIG. 1 is a side view in which a traction device constructed in accordance with the teachings of the invention is mounted to the movable portion of the hospital bed frame lying beneath the mattress and the upper portion of the patient;

FIG. 2 is a perspective view of the traction device with the front panel of the support removed to show the inner mechanism;

FIG. 3 is a front view of the support for the traction device;

FIG. 4 is a partial front view similar to that of FIG. 3 showing the cable means after a change in the vertical position thereof;

FIG. 5 is a sectional view taken along the line 5--5 in FIG. 4;

FIG. 6 is a side view of the support of the traction device taken along the line 6--6 in FIG. 3;

FIG. 7 is an exploded view showing the compensating mechanism for the flexible cable means; and

FIG. 8 is a partial perspective view of the control means on the support which permits the support to be moved toward the patient.

Referring first to FIG. 1, a preferred embodiment of the invention is shown mounted on the frame of a hospital bed and with flexible cable means attached to a patient so as to apply traction. The traction device 10 comprises a base portion 12 adapted for mounting on the frame 14 of a hospital bed 15. In the drawings, the traction device is shown secured to the pivoted portion of the bed frame which underlies the upper portion of the patient. This portion of a hospital bed is frequently pivotable so as to enable a patient to change from a prone position to a sitting position or, if desired, any intermediate position. As will be apparent, the base portion of the traction device could also be applied to other portions of the frame of the hospital bed.

The base portion 12 is secured to the bed frame 14 by means of L-shaped clamps 16 that are threadedly mounted into lugs 18 welded to the mounting bracket 20 on the base support 12. Wing nuts 22 are mounted on the threaded ends 24 of the clamps and serve to tighten the clamps against the underside of the bed frame 14. For added stability, the base portion 12 has an arm 23 that hooks over the side of the bed frame 14.

An upright support 26 is secured to the base portion 12. The support 26 carries flexible cable means 28 for attachment to the patient. As seen from the drawings, the support 26 extends above the level of the patient on the hospital bed so as to provide a point from which traction may be applied. The support 26 is swingably connected to the base portion 12 by a tongue or arm 30 that is rotatably mounted on a shaft 32 secured in a pair of bosses 34 on the mounting bracket 20. An opening 36 is provided on the mounting bracket 20 to accommodate the tongue 30 which is rigidly fixed to the back 38 of the support 26. The support is adapted for swingable movement relative to the base portion in one direction only -- in a direction away from the patient on the bed. Swingable movement of the support toward the patient is normally prevented.

Control of the movement of the support 26 relative to the base portion 12 is accomplished by pressure fluid means including a cylinder 40 and a piston 42. The rod 44 for the piston 42 has a terminal bar portion 45 that is pinned between a pair of brackets 46 fixed to the lower end of the back 38 of the upright support 26. The cylinder 40 has a similar terminal bar 48 secured to it and this terminal bar 48 is likewise pinned between a pair of brackets 50 at the cylinder end of the base portion 12.

Opposite ends of the cylinder 40 are interconnected by conduits 52 and 54. The conduit 54 goes from the rod side of the cylinder to a one-way check valve 56 mounted on the back 38 near the upper end of the support 26. The conduit 52 interconnects the head end of the cylinder with the check valve 56 through an adjustable bleed valve 58. By reason of this arrangement, a force applied to the support 26 tending to pivot or swing the support in a clockwise direction (as viewed in FIG. 2) will cause the support to pivot about the shaft 32. Pivotable movement of the support 26 in this direction will cause the piston rod 42 to be withdrawn from the cylinder 40. This movement will cause air to bleed through conduit 54, pass check valve 56 under the control of the bleed valve 58 to the head end of the cylinder through conduit 52. Any attempt to swing the support 26 in an opposite direction relative to the base portion 12 will be prevented by the check valve 56 which prevents any transfer of air from the head end of the cylinder to the rod end of the cylinder.

In the preferred form of the invention shown in the drawings, the upright support 26 comprises a U-shaped channel member 60. Ordinarily, the support 26 is provided with a front-plate (not shown) which covers the mechanism inside the support. In the drawings accompanying the application, the front-plate has been removed to show the inner mechanism. It is preferred to provide pressure fluid means for applying traction to a patient on the bed. Accordingly, a second pressure fluid means is mounted within the U-shaped channel member 60. The pressure fluid means comprises a cylinder 62 and a piston 64 which reciprocates with respect to the cylinder. The rod 65 for the piston 64 is secured to one end of the flexible cable 28 so that movement of the piston 64 relative to the cylinder 62 moves the flexible cable 28 an equal amount. The lower end of the cylinder 62 is fixedly secured to the back 38 of the channel member 60 by a pin 66. At its upper or rod end, the cylinder 62 has a pressure fluid conduit 68 that connects with a pressure gauge 70, a control valve 72 and a source of compressed fluid, in this case, a cylinder of compressed air 74.

The flexible cable means for applying traction to a patient comprises a cable 28 secured to the piston rod 65. The cable passes over a pulley 76 mounted at the upper end of the channel member 60, then downwardly around an intermediate pulley 78, thence upwardly to a terminal pulley 80 which directs the flexible cable 28 toward the patient. The terminal pulley 80 is mounted externally of the support 26 at one side 82. The pulley 80 is rotatably mounted on a short, stub shaft 84 that extends through an elongated slot 86 in the side 82 of the support 26. The stub shaft is fixed to a bar 86 that has a gear segment 88 formed on its lower half. A curved guide 89 for the flexible cable 28 is also fixedly mounted to the bar 86 so as to closely overlay the terminal pulley 80. The pulley 80 is maintained on the stub shaft 84 by a wing nut 90. The vertical position of the terminal pulley 80 relative to the support 26 may be adjusted by loosening the wing nut 90 and sliding the pulley up or down relative to the support. The amount of adjustment is substantially equal to the length of the elongated slot 86.

Inasmuch as the flexible cable 28 has a fixed length, adjustment of the terminal pulley 80 would, without a compensating mechanism, vary the amount of cable available at the free end for attachment to the patient. To provide a substantially constant length of cable for attachment to the patient, a compensating mechanism is provided on the support 26. The compensating mechanism includes an adjustable mounting for the intermediate pulley 78. The pulley 78 extends partially through a second elongated slot 92 in the side 82 of the upright support 26. A curved guide member 94 is provided for the pulley 78 so as to guide the flexible cable 28. The intermediate pulley 78 is mounted on a short, stub shaft 96 which is secured to a longitudinal mounting plate 98. The plate 98 is adjustably mounted to the back 38 of the upright support 26 by a pair of elongated slots 100, 106. Screws 102, 108 secure the plate 98 to the back 38 with sufficient clearance to enable the plate 98 to slide vertically relative to the support. The plate member 98 has a gear segment 110 disposed parallel to the gear segment 88 but offset therefrom a slight distance. A small gear 112 meshes with the gear segment 110 while a larger gear 114 meshes with the gear segment 88. Both gears are mounted on the same shaft 116.

By reason of this compensating mechanism, adjustment of the terminal pulley 80 causes a compensating adjustment in the vertical position of the intermediate pulley 78. This is done when the wing nut 90 is loosened and the pulley 80 is slidably moved up or down. The movement of the pulley 80 also moves the plate 86 and the gear segment 88. Movement of the gear segment 88 rotates gear 114 which in turn rotates the shaft 116 and causes gear 112 to rotate. Rotation of the gear 112 moves the gear segment 110 half the distance of the gear segment 88 so as to maintain the effective length of the cable the same. In this way, the distance from the centerline of the upper pulley 76 to the centerline of the intermediate pulley 78 to the centerline of the terminal pulley 80 is always constant. See FIGS. 3 and 4.

In operation, the application of traction to the patient will be made under the supervision of the patient's doctor. At that time, the amount of pressure in cylinder 62 will be regulated so as to provide the desired amount of force on the cable 28. At the same time, the position of the terminal pulley 80 will be set so that the traction force is applied in the proper direction. These adjustments may be made with the bed frame in any position but frequently will be made with the pivotable frame 14 in its lowermost position. When done with the frame in this position, the upright support 26 will be at substantially right angles to the base 12 (see FIG. 1). Should the patient thereafter change his bed position by pivoting the bed frame 14 upwardly toward a sitting position, the patient may wish to change the position of the upright support 26. To do so the patient need only reach behind him and push the support 26 away from him. If, by reason of a change in position of the patient, it becomes necessary to change the vertical position of the terminal pulley 80, this can be easily accomplished by loosening the wing nut 90 and repositioning the pulley in the slot 86.

If the bed frame is lowered while the support 26 is in a rearwardly inclined position, such as that shown in FIG. 1, the support will eventually come into contact with the bed frame 15. Ordinarily, swingable motion of the support 26 toward the patient is prevented as previously explained. However, in such a case it is desirable to permit the support 26 to swing toward the patient to avoid wedging the traction device against the bed frame. Accordingly, the support 26 is provided with a long lever arm 118 at the back of the support. Lever arm 118 has a pair of arms 120 that are pivotally secured to the sides 82, 83 of the support. At its upper end the lever arm has a short screw 122 that extends into the support 26. A nut 124 prevents the screw from pulling out and retains the lever arm on the support. Just below the screw 122 the lever arm 118 has a tongue 126 which extends inwardly through an access opening 127 in the back of the support 26. The tongue 126 slidably engages a plunger 128 that extends upwardly from the check valve 56. Depression of the plunger 128 causes the check valve to be held open so as to permit pressure fluid to flow from the roy end of cylinder 40 to the head end of the cylinder. Inasmuch as the tongue 126 is inclined at an angle to the plunger 128, inward movement of the lever arm 118 toward the support 26 causes the tongue 126 to depress the plunger 128. As the traction device 10 comes into contact with the bed frame 15, the lever arm 118 is forced inwardly toward the support 26 causing the tongue 126 to depress the plunger 128 and open the check valve 56. The support arm 26 is thus allowed to swing inwardly toward the patient under the urging of a spring 130 as the bed frame 14 lowers. Lever arm 118 can also be manually pressed so as to swing the support 26 at other times.

Claims

I claim:

1. An adjustable traction device comprising:

a. a base portion adapted to be mounted to a hospital bed,

b. an upright support extending above the level of the bed and swingably secured to the base portion whereby said support may be moved away from a patient in the bed,

c. flexible cable means secured to said support for attachment to a patient in the bed, the vertical position of the point of attachment for said cable means being vertically adjustable relative to said support, and

d. means for applying a force to said flexible cable means to place the patient in traction wherein said force applying means comprise pressure fluid means including a cylinder and piston for the cylinder, said piston being secured to said flexible cable and said cylinder being secured to said base portion.

2. An adjustable traction device as set forth in claim 1 wherein said base portion is mounted on a movable portion of the hospital bed frame.

3. An adjustable traction device as set forth in claim 2 wherein said flexible cable means are provided with a compensating mechanism whereby the cable means may be adjusted vertically on said support without changing the effective length of the cable.

4. An adjustable traction device as set forth in claim 3 wherein said base support is provided with means for limiting free swingable movement of said support relative to said base to a direction away from the patient.

5. An adjustable traction device as set forth in claim 4 wherein said means for limiting swingable movement of said support relative to said base portion comprises second pressure fluid means including a cylinder and a piston for the cylinder, said piston being connected to the swingable support.

6. An adjustable traction device as set forth in claim 5 having control means for disabling said limiting means to permit the swingable support to be moved in a direction toward the patient.

7. An adjustable traction device as set forth in claim 6 wherein said control means is automatically actuated to disable said limiting means whenever the support contacts the bed frame.

8. An adjustable traction device comprising:

a. a base portion adapted to be mounted to a movable portion of a hospital bed frame,

b. an upright support extending above the level of the mattress of the bed and swingably secured to the base portion,

c. first pressure fluid means mounted on the base portion including a cylinder and a piston for the cylinder, said piston being connected to the support whereby the support is freely swingable relative to the base portion in a direction away from a patient on the bed but not swingable relative to the base portion in a direction toward the patient,

d. control means on the support for disabling said pressure fluid means, said control means including means for venting pressure from said cylinder to permit the support to swing toward the patient,

e. a flexible cable on said support for attachment to a patient on the bed, and

f. second pressure fluid means on the support including a cylinder and a piston for the cylinder, said piston being secured to the flexible cable to permit the patient to be placed in traction.

9. An adjustable traction device as set forth in claim 8 wherein said flexible cable upon attachment to a patient passes around a pulley that is vertically adjustable on said support.

10. An adjustable traction device as set forth in claim 9 wherein said flexible cable engages a plurality of pulleys between its attachment to the piston and to the patient and said support is provided with a compensating mechanism whereby the position of said vertically adjustable pulley may be varied without changing the effective length of the flexible cable.

11. An adjustable traction device as set forth in claim 10 wherein said support has a movable lever arm engagable with a valve for venting pressure from the cylinder of said first pressure fluid means.