Invalid pad

March 2, 1948. w. τ. simpson 2,437,006

INVALID PAD '

Filed Sept. 13, 1944 2 Sheets-Sheet 1

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March 2, 1948.

W. T. SIMPSON

INVALID PAD

2,437,006

Filed Sept. 13, 1944

Sheets-Sheet 2

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Patented Mar. 2, 1948

2,437,006

UNITED STATES PATENT OFFICE

2,437,006

INVALID PAD

William T. Simpson, St. Clairsville, Ohio

Application September 13,1944, Serial No. 553,878

Claims.

This invention relates to pads and mattresses used by invalids and other bed-ridden persons and it has for its primary object to· alleviate or to eliminate the pathological effects due to the complete or almost complete immobilization of such a person in a reclined position. It is a well known fact that immobilization causes so-, called bed-soreness, a painful condition which is mainly due to the permanent overburdening of those portions of the body of the patient which have to support the weight. Especially those spots suffer most where bones lie close to the skin and where thin layers of fleshy parts are therefore subjected to heavy pressure from both sides. As a consequence blood circulation is obstructed or even stopped and these spots have a tendency to become necrotic. But even in weight carrying portions of the body where conditions are less unfavourable circulation is poor and sub-normal and disagreeable and even disastrous effects are frequently observed.

The main object of my invention which intends to provide a remedy for these unavoidable pathological consequences of immobilization therefore consists in the provision of means promoting improved blood circulation in all portions of the human body resting on the bed or mattress, said means, moreover, permitting to shift the burden due to the weight regularly to other spots. Said means comprise pulsating or vibrating members, forming the supporting means for the body of the patient which, by virtue of their rhythmic expansion and contraction, produce a massaging and exercising effect affecting the blood circulation favourably and entail a change of the weight supporting spots at frequent intervals.

It is a further object of my invention to provide simple and effective means, adapted for use in beds of every type but especially for use in hospital beds for producing said vibratory or pulsating action, said means preferably comprising a number of elastic and expansible tube sections arranged in close proximity but at a substantial distance from each other which are filled with a pressure fluid subjected to periodic and rhythmic pressure variations.

A further object of the invention consists in providing simple and effective, means for producing the variations in the pressure of the fluid filling the expansible elastic tube sections said means comprising preferably a reciprocating diaphragm enclosed in the pressure space of a pump which is driven by a motor whose speed is adjustable so that the number of pressure variations per time (Cl. 128—33) unit and the shifting and massaging effect can be regulated. With these and other objects to be described below in view, the invention consists in the arrangements, constructions and ⁵ combinations of parts described by way of example in the following specification illustrated in the accompanying drawings and enumerated in the claims.

It is to be understood, however, that the spe¹⁰ cific modifications described and shown are used as an illustration of the invention and are not to be interpreted as limitative.

In said drawings:

Figure 1 is a perspective view of the mattress ¹⁵ or pad arranged in accordance with my invention.

Figure 2 is a cross section through the mattress or pad taken along line 2—2 of Figure 1.

Figure 3 is a cross section through the pressure pump with its reciprocating diaphragm shown at the end of the pressure stroke.

Figure 4 is a perspective view illustrating a further modification of the invention.

₂₅ In the drawing I designates in a general way ⁰ the mattress or pad which is of such size that it can accommodate a person resting thereon; it is however to be understood that in special cases where part of the invalid’s body has to be sup30 ported otherwise or is not immobilized the configuration and the dimensions of the mattress or pad may be chosen in accordance with the special requirements of the case.

The mattress or pad essentially consists of a ₃₃ lower or base piece 2, and an upper piece or cover 3. The base piece may be made of a solid material such as plastics or it may be made of rubber, while the cover is made of a pliable material such as rubber or a woven fabric, the lat40 ter being preferable when the body of the invalid comes into close contact with it. Between these two pieces 2 and 3 a system of tubes 4 is arranged consisting of a number of transverse tube sections 5, 5', 5 joined to each other at their 45 ends. The connections between said transverse sections are preferably made in such a way that a continuous tube is formed meandering through the interior of the mattress or pad from end to end.

One end of the tubing thus formed is closed and may preferably be provided with a valve 6 permitting the adjustment of the pressure of the fluid with which the tubing is filled, and the discharge of any excess fluid. A pressure 55 gauge (not shown) may also be mounted on the

2,437,003 valve. The other end of the tube system Is connected with a pipe 7 leading to a pump 8.

The transverse sections 5, of the tube system are made of elastic or resilient material such as rubber which may expand and contract under the influence of pressure variations imparted to a fluid filling the interior of the tube. These sections form the body support of the mattress. These transverse sections 5, 5', 5 are arranged at such a distance that they cannot touch each other even when fully expanded and partition walls or ribs 15 of solid material such as plastics or wood may be arranged between them in substantial parallelism with the transverse sections. Where the lower part 3 of the pad or mattress is made of solid material the partition walls may be formed by ribs integral with said part 3. These partition walls or ribs 15 constitute a reinforcement of the pad or mattress; they separate the transverse sections and they are so arranged that their upper edges are approximately at one level with the upper portions of the transverse sections when the latter are deflated so that they form the support for the body of the invalid person when the transverse sections 5, 5' contract to a certain extent. By virtue of this arrangement it is possible to relieve those portions of the body which rest on the transverse sections of the tubes entirely at intervals by deflating the said sections to the required extent.

The pump 8, producing the pressure variations of the fluid filling the tube system 4 may be of any approved type and is shown as a diaphragm pump, comprising an elastic diaphragm 9 attached to a reciprocating piston rod iO and reciprocated within a pressure space 16 of the pump 8. The piston rod is driven by an electric motor 13 by means of a connecting rod I f, attached to its fly wheel 12. The speed of the motor is adjustable in the well known manner by means not shown. This regulation of the speed of the motor permits to adjust the variations of pressure per time unit and thus determines the frequency of the vibrations resulting from the expansion and contraction of the elastic walls of the transverse sections supporting the body of the invalid person.

As already mentioned the closed tube system 4, the pipe 7 and the pressure space 16 of the pump are filled with a fluid which is subjected to pressure variations.

When the motor 13 is running with a given speed the pressure of the fluid in the pressure space 16 of the pump varies as the reciprocating diaphragm alternately narrows and widens the pressure space. During each cycle of operations the pressure of the fluid in the pump 8 thus increases and decreases. These pulsations are transmitted to the fluid in the tube system 4 and the section 5, 5' 5” which form the main operative parts of said system thus expand and contract in accordance with these pulsations of the pressure. Therefore these tube sections are alternately pressing against and receding from the body of the person resting on them and this action, when performed regularly and at predetermined intervals, will exercise a massaging effect on those parts of the body with which the tube sections are in contact. This exercising and massaging effect, which is sometimes called “passive exercise” will promote and activate the blood circulation.

If necessary the pressure may be so adjusted that during the low pressure intervals the tube section 5, 5' are deflated to such an extent that the body no longer rests on them but is rested on the partition walls or ribs 15, thereby relieving completely and at regular intervals the portions of the body which originally carried the load.

In the modification shown in Figure 4 two tube systems 17, 18 are used in arrangement which permits an improved distribution of the weight of the invalid person. Each system consists of a main tube 20, 21 respectively running lengthwise through the pad or mattress, from which shorter and closed transverse sections 22, 23 respectively are branching off at right angles. The main tubes may be closed at their ends or provided with the valves, described in connection with Figure 1. The transverse sections 22, 23 of the two systems are so arranged with respect to each other that the tube sections of one system are always placed in the space left between two tube sections of the other system the distance between two adjacent tubes being always such that the tubes may expand fully without ever touching each other as clearly shown In the figure.

The entrance end of the main tubes 20, 21 are connected with pipes 26, 27 leading to the pump 25, which is identical with the pump described in connection with Figure 3. Each system may be connected with a separate pump, both being driven by the same motor, but in the modification illustrated in Figure 4 only one pump 25 is shown supplying a main pipe 28 which is connected with the two branch pipes 26, 27. At the end of each branch pipe a slide valve 29, 30 is provided which is actuated by the motor 13 and alternately opens and closes the connection of the branch pipes 26, 27 with the main pipe 28. The slide valves 29 and 30 are of any approved or well known construction and are not separately illustrated; they may simply consist of discs provided with ports or openings closing and opening the connection between the pipes leading to and from the valve casing 30 and 29, respectively. Or they may consist of cylinders provided with ports or openings establishing connection between the aforesaid pipes.

It is, however, to be understood that the ports or openings in the two slide valves covering or uncovering the communication between the pipes leading to and from the valve casings 29, 30 are symmetrically arranged with respect to a vertical plane passing between the two branch or slide valves and are so positioned that one of the slide valves establishes a communication while the other closes it. If, therefore, the connecting rod is moved forward one of the two branches, say the branch 26, will be connected with the pipe 23 while the other is closed and when the connecting rod 31 is moved backward, the connection which was first closed (say the connection through pipe 27) is opened while the connection which was opened upon the forward stroke of rod 31 (say the connection through pipe 26), is closed.

The connecting rod 31 is reciprocated in a manner clearly shown in Fig. 4 by means of a swinging link whose movement is derived from a disc rotated by the motor 13.

With this system the body of the invalid person alternately rests on the tube sections of one or the other system and therefore one of the main sources of bed soreness, the permanent pressure of the weight on the same spots, is eliminated. Moreover the number of spots which are subjected to an exercising and massaging action is doubled.

From the above description it will be seen that

2,437,006 the invention permits effective suppression and elimination of some of the detrimental effects of the immobilization of a completely invalid person. Permanent attendance in view of a frequent change of position is no longer necessary. The main point is however the improvement of the circulation in those parts of the body which are most affected by the heavy pressure of the weight and therefore the invention permits a very marked improvement of the patient’s condition.

It is to be understood that the foregoing description has been made with the intent of illustrating the invention but not of limiting its scope to the modifications illustrated. The details of the arrangement and of the construction of the parts may clearly be further modified without departing from the essence of the invention.