Therapeutic Device Oscillating Device

Abstract

A therapeutic device used to relieve and prevent heel cord contractures, including a foot-supporting plate member pivotally mounted about a laterally extending axis located substantially beneath the ankle joint of the supported foot, and including a reciprocating hydraulic motor connected to the plate member to cause oscillation thereof. They hydraulic circuit for operating the motor includes a shiftable reversing valve that is selectively operable to control the angular extent of the plate member oscillations, and includes selectively adjustable flow control valves for regulating the speed of oscillation of the plate member. Additionally, the hydraulic circuit may include a selectively adjustable pressure relief valve for controlling the force applied to the supported foot by the plate member.

Description

BACKGROUND OF THE INVENTION

There are a number of medical conditions (i.e., injury or disease to the nervous system, and vascular insufficiency of the lower extremity) which can have a secondary side effect resulting in the patient's heel cord (tendo achilles) becoming contracted so that normal movement of the patient's foot at the ankle joint is severely limited. Similarly, fractures and related maladies of the leg, foot and ankle joint usually necessitate placing these members in a cast so that they will remain immobilized for long periods of time, and the resulting inactivity of the heel cord often causes it to contract in an extent which restricts the freedom of movement of the foot at the ankle joint.

Whatever the cause of the contracture of the heel cord, this condition can be relieved, and sometimes even prevented, if proper therapy is administered to the patient to gradually stretch the heel cord until it returns to normal. This therapy consists generally of applying pressure simultaneously to the heel portion and the ball portion of the foot to cause dorsiflexion of the foot about the ankle joint, and, since the degree of the contracture and the pain associated with the therapy vary over wide ranges with different patients, such therapy has heretofore almost universally been administered manually by a trained physical therapist who can vary the pressure which is applied to the foot and the extent of foot movement in response to the requirements of the individual patient.

The nature of the therapy is such that, to be effective, it must be administered repetitiously over a period of time so that the heel cord will be stretched progressively without unnecessary discomfort to the patient and, as a result, a generous amount of time and labor is expended by the therapist in attending each patient. Some effort has been made to provide mechanical assistance to the therapist as evidenced by the device disclosed in U.S. Pat. No. 3,020,046, but this device still requires the therapist to move the foot manually. Additionally, there are several prior disclosures of mechanical devices designed to exercise the muscles in the foot, representative disclosures of this type being found in U.S. Pat. No. 2,216,764 and U.S. Pat. No. 3,022,021. However, these prior art devices are not suitable for use in treating heel cord contractures because they do not impart to the foot the correct dorsiflexion required to stretch the heel cord and, more importantly they do not have facilities for selectively controlling the movement of the foot so as to satisfy the individual needs of each patient to which therapy of this type is administered.

The present invention, on the other hand, provides a therapeutic device which not only assures that the correct flexions are continuously imparted to the foot, but which also includes selectively adjustable control features that permit the variables associated with the proper administration of this therapy to be regulated to a substantially infinite degree.

SUMMARY OF THE INVENTION

The therapeutic device of the present invention includes a foot-supporting plate member which is pivotally mounted in a mounting frame for oscillation about a pivot axis that lies substantially directly beneath the ankle joint of the supported foot so that oscillation of the plate member imparts the correct plantar flexion and dorsiflexion to the foot supported thereby. The plate member is oscillated automatically by a motor operatively connected thereto, this motor being provided with controls for selectively regulating the speed and the extent of the oscillation of the plate member, and the pressure applied to the supported foot by the oscillating plate member.

In the preferred embodiment of the present invention, the motor is hydraulically operated and includes a double-acting reciprocating piston connected to the plate member whereby the reciprocating motor of the piston causes oscillation of the plate member about its pivot axis. The hydraulic circuit for operating the motor includes a positive displacement gear pump providing a source of pressurized fluid, a conduit system connecting the pump to the opposite sides of the reciprocating piston, and a shiftable, two-position valve interposed in the conduit system between the pump and the motor for alternately supplying fluid to the opposite sides of the piston to cause reciprocation thereof. Thus, by controlling the shifting action of this two-position valve, the extent of oscillation of the plate member can be regulated since the direction of movement of the plate member will change in response to the shifting of the two-position valve. Accordingly, the present invention provides a pair of oppositely acting solenoids connected to shift the two-position valve in opposite direction, and each of these solenoids is energized by an electrical switch. These switches are closed by corresponding switch-actuating elements oscillating with the plate member and adjustable with respect thereto so that the points at which the electrical switches are closed by their associated activating elements may be selected to determine thereby the limits of oscillation of the plate member.

To control the speed of oscillation of the plate member, the present invention provides a pair of selectively adjustable flow control valves in the hydraulic circuit, these valves being disposed, respectively, in the hydraulic lines leading to the motor at the opposite sides of the reciprocating piston thereof. Thus, by varying the flow of fluid to or from the motor, the reciprocating speed of the piston can be controlled to regulate the oscillating speed of the plate member.

Preferably, the hydraulic circuit is also provided with a selectively settable pressure relief valve which permits the hydraulic pressure supplied to the motor to be controlled for regulating the force or pressure applied to the supported foot by the oscillating plate member.

Finally, the therapeutic device of the present invention is provided with an extendable leg-supporting member which is carried by the mounting frame at a position adjacent the plate member, and this leg-supporting member is provided with straps or the like for holding the patient's leg immobilized during oscillation of the patient's foot by the plate member. Such immobilization of the leg assures that the oscillating motion of the plate member is properly imparted solely to the patient's foot to cause the necessary flexions thereof about the ankle joint.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a side elevational view of the therapeutic device of the present invention, the hydraulic and electrical circuits being omitted for clarity of illustration;

FIG. 2 is a plan view of the therapeutic device illustrated in FIG. 1;

FIG. 3 is a right-hand end view of the therapeutic device illustrated in FIG. 1;

FIG. 4 is a plan view of the foot supporting plate member;

FIG. 5 is a schematic diagram of the electrical and hydraulic circuits for the therapeutic device of the present invention.

DESCRIPTION OF THE PREFERRED EMBODIMENT

Referring now in detail to the drawings, the therapeutic device of the present invention includes a generally open, rectangular mounting frame 10 having a pair of upper support members 12 and a pair of lower support members 14 all extending longitudinally in parallel relation. A pivot shaft 16 is journaled in the upper support members 12 and extends thereacross, and a foot-supporting plate member 18 is fitted on the pivot shaft 16 for pivotal movement about the laterally extending axis formed by the pivot shaft 16. The plate member 18 is provided with a curved, upstanding wall 20 and a pair of straight, upstanding walls 22 arranged to receive a human foot and position it properly with respect to the pivot shaft 16, and straps 24 are provided for holding the foot in place on the plate member 18. The location of the curved wall 20 on the plate member 18 is such that when the heel of the supported foot is disposed thereagainst, the pivot shaft 16 will be located substantially directed beneath the ankle joint of the foot so that oscillation of the plate member 18 on the pivot shaft 16 will result in the previously described plantar flexion and dorsiflextion being imposed properly on the foot.

To make certain that this oscillating movement of the plate member 18 is correctly applied to cause the desired movement of the foot about the ankle joint rather than other movements (i.e. bending of the leg at the knee), the device of the present invention preferably includes a leg-supporting member 26 carried on the upper supports 12 by sliding brackets 28, 30 that permit the leg-supporting member 26 to be extended selectively with respect to the mounting frame 10, the brackets 30 being secured to the leg-supporting frame 26 and having wing bolts 32 which can be tightened against the upper supports 12 to hold the leg-supporting member 26 in place at any selected position. The leg-supporting member 26 is also provided with straps 34 for securely holding the supported leg in place.

The plate member 18 is oscillated by a double-acting hydraulic motor 36 that is anchored to the mounting frame 10 through a pivotal connection fitting 38 and that includes a reciprocating piston rod 40 pivotally connected to an arm 42 extending beneath the central portion of the plate member 18, this connection being in the form of a yoke 44 fitted on the piston rod 40 and a pivot pin 46 extending through the yoke 44 and the end of the arm 42 as best seen in FIG. 2. Thus, reciprocation of the piston rod 40 will cause the plate member 18 to be oscillated on pivot shaft 16.

To operate the hydraulic motor 36, a hydraulic circuit is provided which includes a number of components interconnected by hydraulic and electrical lines which have been deleted from FIGS. 1 through 4 for purposes of clarity, but which are shown in the schematic diagram in FIG. 5. This hydraulic circuit includes a source of hydraulic pressure which, in the preferred embodiment of the present invention, is a conventional pumping unit 48 including a pump motor 50, a gear pump 52, and a reservoir tank 54, all assembled together as a compact unit and mounted to mounting frame 10. Also attached to the mounting frame 10 are a shiftable, two-position safety valve 56 operated by a solenoid "A" (FIG. 5), and by a shiftable, two-position motor control valve 58 operated by a pair of oppositely acting solenoids "B" and "C" as will be explained in greater detail presently. The solenoid "A" is energized by a manually operable primary on-off electrical switch 60 located at one end of the mounting frame 10, and the solenoids "B" and "C" are energized by a pair of contact switches 62, 64 mounted on one of the upper supports 12. The switches 62, 64 are closed by corresponding switch-closing elements 66, 68 which are threaded screws having their lower ends depending to an adjustable extent from a bracket 70 that is attached to the pivot shaft 16 for oscillation therewith.

The hydraulic circuit also includes a pressure relief valve 72 having a control knob 72' extending from a control panel 74 at one end of the mounting frame 10, and a pair of flow control valves 76, 78 provided with adjusting knobs 76', 78' located at the control panel 74. Finally, the control panel 74 includes an oscillating-control on-off switch 80, a timing device 82 having appropriate graduations on the face thereof, and an indicator light 84 which is turned on when the primary switch 60 is at its on or closed position.

To explain the operation of the therapeutic device of the present invention, attention is directed the schematic hydraulic and electrical line diagram illustrated in FIG. 5, the hydraulic circuit being shown in full lines and the electrical circuit being shown in broken lines.

The hydraulic circuit includes a primary leg 86 leading from the pump 52 to the motor control valve 58, and two secondary legs 88, 88' leading from the motor control valve 58 to each end of the hydraulic motor 36 on opposite sides of the reciprocating piston 36' therein. The primary leg 86 includes a pressure indicator gauge 90, and the previously mentioned pressure relief valve 72 is selectively adjustable to control the pressure in the hydraulic system by bypassing some of the hydraulic fluid out of the system when the pressure exceeds that for which valve 72 is set. Each secondary leg 88, 88' includes a one-way check valve 92, and a bypass line 94 in which the aforementioned flow control valves 76, 78 are located, respectively; the check valves 92 acting to permit the hydraulic fluid to be supplied directly to the hydraulic motor 36 at the intake side thereof and to be bypassed through the flow control valve 76 or 78 at the discharge side of the hydraulic motor 36. A safety line 96 extends from one of the secondary legs 88 to a return reservoir, and the previously mentioned safety valve 56 is interposed in the safety line 96 to control the flow to this return reservoir. When primary switch 60 is closed, solenoid "A" will be energized to move safety valve 56 to the right in FIG. 5 to close the lines 96. However, when switch 60 is open to cease operation of the therapeutic device, solenoid "A" will be deenergized and safety valve 56 will move to the left under its own bias whereby safety line 96 will be opened to vent any pressure in the hydraulic circuit.

When the plug 98 is connected to a suitable 110-volt supply, and the primary on-off switch 60 is closed, an electrical circuit is completed which starts the pump 52 to pressurize the hydraulic circuit. However, the plate member 18 will not begin to oscillate until oscillating control switch 80 is closed to complete the electrical circuit between the contact switches 62, 64 and the corresponding solenoids "B" and "C". When this electrical circuit is completed by closing switch 80, it will be observed that as the piston 36' of the hydraulic motor 36 moves to its left-hand position in FIG. 5, the switch 62 is closed (by switch-closing element 66 in FIG. 1) and solenoid "B" is energized to move the motor control valve 58 to the right in FIG. 5 whereupon the fluid from the pump 52 will flow through the secondary leg 88 and cause the piston 36' to move to the right. When the piston 36' then moves a sufficient distance to close switch 64, solenoid "C" will be energized so as to move the motor control valve 58 back to the left again whereupon fluid from the pump 52 flows through secondary leg 88' to reverse the movement of the piston 36'. Thus, the direction of movement of the piston 36' is continuously reversed and the plate member 18 will, accordingly be oscillated continuously.

It will be noted, of course, that the extent of this oscillation of plate member 18 is determined by the points at which contact switches 62, 64 are closed, and since the switch-closing elements 66, 68 can be readily adjusted, as previously described, the operator can choose substantially any range of oscillation. Moreover, by turning either or both of the control knobs 76', 78', the operator can regulate the flow in the secondary legs 88, 88', and thereby selectively set the speed of oscillation of the plate member 18. Finally, by adjusting the knob 72' which controls the setting of pressure relief valve 72, the operator can selectively control the pressure in the hydraulic system and the pressure which is applied to the supported foot by the oscillating plate member 18.

With this wide range of control option available to the operator, it will be apparent that the therapeutic device of the present invention can be used to exceptional advantage in administering proper therapeutic movement to a large number of patients because the operator can select substantially any movement pattern required to satisfy the individual requirements of each patient. Moreover, after the operator has strapped the patient's leg and foot in place (using straps 24 and 34) and adjusted the several controls to obtain the movement pattern, the operator may leave the patient while the therapy is being continuously administered, and attend to other patients. In this case, it may be desirable to provide the device with a remote on-off switch (not shown) which the patient can hold and use to stop the oscillating movement of the plate member 18 when desired or if there is any malfunction of the equipment.

The present invention has been described in detail above for purposes of illustration only and is not intended to be limited by this description or otherwise to exclude any variation or equivalent arrangement that would be apparent from, or reasonably suggested by, the foregoing disclosure to the skill of the art.

Claims

I claim:

1. A therapeutic device for use in relieving and preventing heel cord contractures or the like, said device including a mounting frame having a foot-supporting plate member mounted thereon for pivotal movement about a laterally extending axis located substantially directly beneath the ankle joint of the supported foot, means for automatically oscillating said foot plate member about said axis thereof, control means for selectively regulating the speed and the angular extent of the oscillation of said plate member and for selectively controlling the force applied to said supported foot by said oscillating plate member, and an extendable leg-supporting member carried by said mounting frame adjacent said plate member, said leg-supporting member including securing means to hold said supported leg immobilized during oscillation of its associated foot by said plate member.

2. A therapeutic device as defined in claim 1 and further characterized in that said oscillating means includes a fluid motor having a double-acting reciprocating piston operatively connected to said plate member, a source of pressurized fluid and conduit means connecting said source to the opposite sides of said piston, and shiftable valve means in said conduit means for alternatively supplying fluid to the opposite sides of said piston, and in that said control means includes selectively adjustable flow varying means in said conduit means for varying the flow of fluid to said piston to regulate the speed of oscillation of said plate member.

3. A therapeutic device as defined in claim 2 and further characterized in that said conduit means includes first and second conduits connected respectively to said fluid motor at each side of said piston, and in that said flow varying means includes a selectively adjustable flow control valve in each of said first and second conduits.

4. A therapeutic device as claimed in claim 3 and further characterized in that said control means additionally includes a pair of oppositely acting solenoids connected to operate said shiftable valve means, an electrical switch connected in circuit with each of said solenoids for energizing said solenoids, respectively, when said switches are closed, and selectively adjustable switch-closing means movable with said plate member to close said switches alternately for determining thereby the limits of oscillation of said plate member.

5. A therapeutic device as claimed in claim 4 and further characterized in that said plate member is connected to a pivot shaft carried by said mounting frame, in that said switch-closing means includes a bracket member fixed to said pivot shaft for movement therewith and having a pair of screw elements adjustably depending from said bracket member, and in that electrical switches are carried by said mounting frame for disposition in the path of screw elements, respectively, during oscillation of said plate member and said pivot shaft.