WO1983003747A1

WO1983003747A1 - Warning device for monitoring the position of a part of a human body

Info

Publication number: WO1983003747A1
Application number: PCT/SE1983/000153
Authority: WO
Inventors: Kaj Laserow
Original assignee: Kaj Laserow Ab
Priority date: 1982-04-23
Filing date: 1983-04-22
Publication date: 1983-11-10

Abstract

A warning device for monitoring the position of a part of a human body comprises an electric circuit including at least one electric battery (41), a signal device (43) and a current controlling means (44). The current controlling means (44) is designed to be attached to the part of the body to be monitored and to be actuated by the position of the monitored part of the body for controlling the operation of the signal device (43). The current controlling means (44) comprises a conical element (45) having an adjustable apex angle and containing a movable ball (53). The ball is arranged to abut an electric contact (54), when the monitored part of the body is tilted over a certain angle, and to close a current circuit for activation of the signal device (43). The signal from the signal device indicates that the monitored part of the body is in a harmful position. Alternatively, the current controlling means can be a reed relay provided with a slidable sleeve carrying a permanent magnet. The movement of the permanent magnet along the relay provides a contact between the reed elements in the relay, so that a current circuit for the signal device is closed. According to another alternative, the current controlling means is a tube provided with contacts in which a movable ball is positioned. The reed relay as well as the tube containing the ball can be adjusted in relation to a vertical line.

Description

Warning device for monitoring the position of a part of a human body

Technical Field-

The present invention is related to a warning device intended to caution the user not to perform certain harmful movements with a part of the body-. Background Art

Pain in the back is a very common .disease and, accor¬ ding to statistics, about SO?o of the population have suf¬ fered from backache before reaching the age of 50 years. The pains can be avoided or at least alleviated, if too heavy loads on the back and the disks of the spinal column, respectively, are avoided. If the back is bent to an angle of 90° and a load of 10 kilograms is lifted, the lumbar region is loaded with about 700 kilograms. If the patient can be taught to lift the loads with bent knees and, at that time, keep the back in an upright position, too heavy loads on the lumbar region can be avoided. However, expe¬ rience shows that it is very difficult to teach the patients throughout to bend the knees and to keep the back in an upright position when lifting loads. Disclosure of Invention

The object of the invention is to provide a warning device that will caution the patient when a certain .part of the body, e. g. the back, is about to reach a harmful posi¬ tion. This object is achieved by combining in an electric circuit at least one battery, at least one means or gauge actuated by the monitored part of the body and controlling the electric current, and a signal device. The current controlling means or gauge is designed to be attached, at least with one part, to the monitored part of the body. In the present specification and the attached claims, the term "current controlling means'* includes a device disrupting the electric current (switch) εis well as a device changing the current (impedance).

OMPI The part of the body can be monitored either with re¬ spect to its absolute position, i. e. in relation to a horizontal or vertical line, irrespective of the angle bet¬ ween the monitored part of the body and another part of the body, or with respect to its position in relation to an¬ other part of the body^", e. g. the. angle between the spinal column and the lumbar region. ^* • -

In the first case, a device sensitive to position, e. g. a mercury switc.h of a.prior art type or any other position indicating device, is used as a current control¬ ling device. In the second case, a device sensitive to position, e. g. a toggle switch, can be used, if provided with a simple means operating at a predetermined .angle. Furthermore, one or more resistors sensitive to tensile strain, i. e. strips changing resistance in response to a varying tensile strain. Resistors of this type are already well known. In the first case the device is attached to the monitored^' part of the body, and in the second case the device has to-be attached to the part of the body to be monitored as well as to another part of the body.

The device can be attached to the body in different ways, e. g. by means of plaster, bandage, a tight vest, etc. The device is preferably adjustable with regard to position and attached to a carrier, and the carrier is then attched to the body. By changing the position with regard to the carrier, e. g. by tilting a mercury switch or moving the point of attachment of a resistance strip, the position of the monitored par of the body In which a signal is to be generated, can be adjusted. The signal generator may be a bulb, a buzzer or a similar device. If desirable, a manually operable switch of conventional design can be pro¬ vided in the circuit, so that the device can be disconnec¬ ted.

Some exemplary embodiments of the invention will now be described with reference to the accompanying schematic drawings.

MPI Brief Description of Drawings

Fig. 1 shows a first type of gauge in operation. Fig. 2. shows a unit for operation. Fig. shows a second type of gauge. Fig. 4 shows a warning device having a third type of gauge. Figs. 5 and 6 show two further embodiments of a gau¬ ge. Best Mode for Carrying .Out the Invention

According to Fig. 1, a strain gauge 20 is attached by means of tape at points 21,22 to the lumbar region .10 of a patient. The strain gauge 20-is connected through two.wires 23 to a unit 24 (Fig. 2), which can be carried e. g. in a pocket. This unit comprises one or several batteries 25, a means 26_.arranged to pass a current from the batteries 25 to a buzzer 27 at a predetermined and preferably adjustable change of the resistance of the strain gauge 20. The unit also comprises a manually operable switch 28, by means of which the device can be put into operation or made nonόpe- . rative. • •

Another type of gauge, according to Fig. 3,^" comprises a mercury switch 30 attached to a turnable disk 31. The disk 31 is mounted in bearings in a carrier 32 which is intended, o be attached to the body by means of a bandage 33. For monitoring the back, the bandage 33 is attached^* to the upper portion of the body, so that the carrier 32 is positioned slightly below the armpit. This gauge is also connected to the unit 24 by means of the two wires 23. In this case, however, the means 25 can be omitted in unit 24. The warning device shown in Fig^*. 4 comprises a tubular cover 40 containing a battery 41, an electronic unit 42, a signal device 43, and a gauge unit 44 and thus serving as a support for the included components. The gauge unit 44 comprises a^* etal strip 45 wound to a coil. The outside turn 45a of the coil is attached to the cover 40 and the inside turn 45b is attached to a central body 46. The body 46 is rigidly attached to the end of a threaded rod 47. The rod is positioned along- the longitudinal axis of the tubu¬ lar cover 40 and runs through a nut 48 attached to an

OMPI adjusting wheel 49 that is mounted in the cover 40 so that it can be turned. The wheel is provided with a central hole 50 into which the threaded rod penetrates, and is attached to the cover by means of a locking pin 51 running through the wall of the.cover and into a circular, groove 52 at the outside of the wheel. By turning the wheel 49 provided with the nut 48, the threaded rod 47 that is in engagement with the nut 48 can be moved in axial direction, so that also the body 46 is moved^' in axial direction. This movement will move the inside turn 45b o the coiled metal strip 45 in axial direction, so that the metal strip forms a cone having its apex downwards and having an adjustable apex angle, as shown- in Fig. 4. The cone formed by the metal strip contains a metal ball 53, and a metal disk 54 is pro- vided above the upper, outside turn 45a of the the coiled metal strip. The metal disk 54 has .a conical shape with the apex upwards and is positioned at a certain distance from the top edge of the outside turn 45a o -the metal strip, s'o that the metal strip 45 and the metal disk 54 are not in a direct metallic contact with each other. Furthermore, the metal strip .45 and the metal disk 54 must be so assembled in the tubular cover that no electric connection exists between them..However, the distance between the outside turn 45a of the metal strip and the metal disk 54 must not be so large that the metal ball 53 cannot bridge the dis¬ tance and provide a metallic and thus electric connection between the metal strip 45 and the metal disk 54 which form two terminals in an electric circuit.

The warning device shown in Fig. 4 is primarily inten- ded to be attached to the back of a person in order to cau¬ tion the person against unsuitable back angles. The warning device is to be attached to the back of the person in the position shown in Fig. 4, i. e. with the apex downwards when the back of the person is in a substantially vertical position. When the person is tilting his back over a cer¬ tain angle in relation to a vertical line, the metal ball will roll over the inside surface of the cone formed by the

metal strip, until it is abutting against the metal disk. The metal ball will then provide a metallic connection bet¬ ween the metal strip and the metal disk. This metallic con¬ nection closes an electric circuit through the metal strip 5 and and the metal disk, and the current flowing through the circuit can be used for controlling the signal device so that a warning signal is emitted. The tilt angle causing the signal device to emit the warning signal can be adjus¬ ted by means of the turnable wheel, because the turning of 10 the wheel changes the apex angle of the .cone formed by the metal strip. The more acute the apex angle of the cone is, . the larger is the angle open for- tilting the back without emission of. a warning signal from the signal device. The^* electronic unit of- the warning device can be 15 expanded, so that the device can record the number of alarms per day, if desirable for statistical reasons.

Fig. 5 shows another embodiment of a gauge consisting of a reed relay 55 of conventional type comprising two flexible reed elements 56,57. The reed elements_^ are provi- 20 ded in a tube^* 58, and a' sleeve 59 is surrounding the tube and slidabl^'e on the tube. The sliding movement of the slee¬ ve is limited by two stop collars 60,61 provided- on^' the tube 58 adjacent its ends. The sleeve 59 is provided with a permanent magnet in the shape of a bar in parallel with the 25 longitudinal axis of the tube. The reed elements 56,57 ex- ^• , tend into the tube from opposite ends of the tube and are so positioned that only the ends 56a,57a run in parallel at ^• the side of each other. When the sleeve 59 with the. per¬ manent magnet 62 is in the position shown in Fig. 5, the 30 lines of magnetic force of the permanent magnet run only through the reed element 56, and the ends of the reed ele¬ ments 56,57 are separated from each other, so that no cur¬ rent path through the reed relay exists. When the sleeve 59 with the permanent magnet 62 is close to the stop collar 35 61, the lines of force of the permanent magnet run through both the reed elements, the ends 56a,57a of the reed ele¬ ments attracting each other so that a current path is clo- sed through the relay. The sleeve 59 slides on the tube 58, when the tube is so tilted that the stop collar 60 is posi¬ tioned above the stop collar 61..

The stop collar 61 is provided with an extending arm 63 articulately ^"connected by means of- a screw joint to an arm 64 on an attachement^* plate '65_. for attachement of the gauge, e.g. on a back to be monitored. The tube 5.8 can be adjusted to a desired angle position in relation to the back by means of the screw joint, so that the sleeve 59 will slide on the tube 58, when the back is bent over a critical angle. The reed elements 56,57 are connected in the electric circuit of the signal device, so that closure of the current path through the reed relay activates the signal device.. Finally, Fig. 6 shows another possible embodiment of the gauge. In this example, the gauge comprises a closed tube 66 in which a metal ball 67 is positioned with a clea¬ rance so that the ball can roll in the tube. Two electric contacts 68,69 are positioned at one end of the- ube in such a way that the contacts are bridged by the ball if the ball rolls through the tube to the end where the contacts are positioned. The tube 66 can be mounted in the same way as the tube 58^' in the embodiment according to Fig. 5 and operates in the same way. It is evident that the described devices according to the invention can be used also for monitoring other, parts of the body, e. g. injured legs or arms, or for monitoring back movements sideways, e. g. by positioning the gauge according to Fig. 3 at the back bone and positioning the mercury switch 30 on the support 31 symmetrically with regard to the back bone and providing the gauge with con¬ tacts at both ends.

A device according to Fig. 2 and a gauge according to Fig. 3 can also be combined in a single cover attachable to the part of the body- to be monitored. It is advantageous to use miniaturized electrical components and a battery of the type used in electrical wrist-watches having alarm capabi- lity. The complete device can then be designed in the same size as such a wrist-watch.

While only a few embodiments of the gauge have been described and shown, it is evident that many modifications and variations are possible within the scope of the inven¬ tion. The conical element of the embodiment according to Fig. 4 must not necessarily^' consist of a metal .strip but can be e. g. a bellows, and the metal disk may be replaced by one or more metal plates. ^• Furthermore, it is not neces- sary that the provided control current circuit is closed by a direct metallic connection through a metal ball, but the ball can instead be caused to activate a contact element that in turn^' closes the current circuit. The adjustable attachement of' the gauge can also be carried out in many ways.

OMPI _> Λ_ W1P0 ,

Claims

1. Warning device for monitoring the position of a part of a human body, characterized in that it coifiprises an elect¬ ric circuit including at_. least. one'electric battery ^"(25,41), a signal device (27,43) and a current controlling means (20,30,44,55,66-69), the. current controlling means being designed to be^' attached tio the part (10) of the body to be monitored and to be actuated by the position of the monitored part of the body for controlling the operation of the signal device (27,43).

2. Warning device according to claim 1, characterized- in that the- cμrrent controlling means (30,44,55,66-69) is sen¬ sitive to the absolute position of the monitored part (10) of the body, i. e. the position in .relation to a vertical line.

3. Warning device according to claim 2, charactrized in that the^" current controlling means is a mercury switch (30).

4. Warning device according to claim 2,• characterized in that the current controlling means (44) comprises a conical element (45) having an adjustable apex angle; an electric contact (54) adjacent the conical element; and a movable metal ball (53) positioned in the conical element and arranged to-abut the electric contact (54), when the moni¬ tored part of the body is tilted in relation to the verti- cal line over a certain limit angle, for delivering a con¬ trol signal to the signal device (43), so that the signal device emits a warning signal.

5. Warning device according to claim 4, characterized in that the conical element consists of a metal strip (45) coiled to a spiral and having an outside turn (45a) connec¬ ted to a support (40) and an inside turn (45b) arranged to be moved along the axis of the cone by means of a screw device (46-49), so that apex angle of the cone can be changed.

0MPI_

6. Warning device according to claim 2, characterized in that the current controlling means is a reed relay (55) having two reed elements.(56,57) and being provided with a slidable sleeve (59) which can be moved along the reed relay between two positions and which carries a permanent magnet (62) controlling the positions of the reed elements (56,57). . .

7. Warning device according to^* claim 2, characterized in that the current controlling means consists of a tube (66) in which a movable metal ball is positioned, one end of the tube being provided with two electrical contacts (68,69) arranged to be bridged by the metal ball, so that an elect¬ ric current- path is closed.

8. Warning device according to claim 1, charac erized in that the current controlling means (20) is sensitive to the relative position of the monitored part of the body, i. e. its position in relation to another part of the body, and is mechanically attached to the monitored part of the body as well as to- the other part of the body.

9. Warning device according to claim 8, characterized in that the current controlling means is a^' resistor (20) sen¬ sitive to tensile strain.

10. Warning device according to any of claims 1-9, characte¬ rized in that the current controlling means (30,35) is attached to a support (32,63-65) and adjustable with regard to position, the support being attached to the body of the patient, so that the emission of a signal can be set by adjusting the position of the current controlling means (30,35) in relation to the support.

OMPI