HAND GRIP DYNAMOMETER

BACKGROUND Technical Field

[0001] The embodiments herein relate to an apparatus for measuring the grip strength of a person's hand, and, more particularly, to measuring the grip strength of a person's hand and the pinch strength between two fingers/digits of the hand using a hand grip
dynamometer.

Description of the Related Art

[0001] In medical applications, values of grip strength of a person's hand and pinch strength between two fingers/digits of the hand play an important role in determining his/her muscular strength and physical status. The values can be used to measure physical strength of sports persons and military cadets. They are also useful for doctors to objectively monitor the progress of patients who have suffered hand injuries, either through accidents or through debilitating diseases such as arthritis, or those who have undergone hand surgery, for example, to replace one of the finger joints with a prosthetic joint.

[0002] Several devices exist for measuring grip strength of the hand, but these suffer from several disadvantages. One such device is described in a paper by Petoskey et al, "Proceedings of the IEEE 1981 National Aerospace and Electronics Conference, Dayton, Ohio, USA (19th to 21st May 1981)". This device is designed to measure the grip strength of a pilot's hand, specifically for the purpose of examining isometric performance characteristics. It does not include any means for also measuring the pinch strength between two digits, and it would not in any case be suitable for use by a person having fixed flexion deformities resulting from say arthritis, which prevent the person from unclenching their hand completely.

[0003] In making digit strength surveys such as for measuring the force exerted by the thumbs or other digits, as for example, to be applied to hand operated control systems, the relative position of the digits and the hand is not provided in the existing systems. Further, their force readings interfere with force inputs from other parts of the body. Variations in hand size may not be accounted for. Accordingly, there is a need for system that can measure both grip strength as well as pinch force of an individual more accurately.

SUMMARY

[0001] In view of the foregoing, an embodiment herein provides an apparatus for measuring grip strength and pinch strength applied by a user to a hand grip dynamometer. The apparatus includes a circular rod having a first beam and a second beam, a horizontal slot which separates the first beam and second beam. A notch is directly coupled to the first beam and second beam, the notch induces a strain in at least one of the first beam or second beam at a region of the notch based on user's grip strength and pinch strength. A strain gauge directly connected to the region of the notch. Resistance of the strain gauge changes due to the induced strain. A Wheatstone bridge is connected to the strain gauge through a wire. The Wheatstone bridge generates a signal based on said change in said resistance of said strain gauge, wherein said signal includes a voltage. An amplifier amplifies the voltage of the signal obtained from Wheatstone bridge. An ADC converts amplified signal to a digital signal. A PIC microcontroller calibrates a load applied by the user and a LCD display to show a digital value and a load value.

[0002] These and other aspects of the embodiments herein will be better appreciated and understood when considered in conjunction with the following description and the accompanying drawings. It should be understood, however, that the following descriptions, while indicating preferred embodiments and numerous specific details thereof, are given by way of illustration and not of limitation. Many changes and modifications may be made within the scope of the embodiments herein without departing from the spirit thereof, and the embodiments herein include all such modifications.

BRIEF DESCRIPTION OF THE DRAWINGS

[0004] These and other features, aspects, and advantages of the present embodiment will become better understood with regard to the following description, appended claims, and accompanying drawings, in which:

[0005] FIG. 1 illustrates a perspective view of a hand grip dynamometer for the measurement of grip strength and pinch strength of a user according to an embodiment herein; and

[0006] FIG. 2 is a flow diagram that illustrates the working procedure of the hand grip dynamometer of FIG. 1 according to an embodiment herein.

DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS

[0007] The embodiments herein and the various features and advantageous details thereof are explained more fully with reference to the non-limiting embodiments that are illustrated in the accompanying drawings and detailed in the following description. Descriptions of well-known components and processing techniques are omitted so as to not unnecessarily obscure the embodiments herein. The examples used herein are intended merely to facilitate an understanding of ways in which the embodiments herein may be practiced and to further enable those of skill in the art to practice the embodiments herein. Accordingly, the examples should not be construed as limiting the scope of the embodiments herein. Referring now to the drawings, and more particularly to FIG. 1 through FIG. 2, where similar reference characters denote corresponding features consistently throughout the figures, there are shown preferred embodiments.

[0008] FIG. 1 illustrates a perspective view of a hand grip dynamometer 100 for the measurement of grip strength and pinch strength of a user according to an embodiment herein. The hand grip dynamometer 100 includes a circular rod/beam 102, a slot 104, a notch 106, a strain gauge 108, and a wire 110. In one embodiment, diameter of the circular rod 102 is 25.4mm and length is 120mm approx. In one embodiment, the width of slot 104 is 3mm and cuts longitudinally for a depth of 82mm in the circular rod 102. In one embodiment, at the end of the slot 104, a notch 106 is made with the size of 19mm in diameter and depth of the notch 106 on either side of the circular rod 102 is 7.7 mm to ensure that the beam 102 withstands a maximum load of 120kg with safety. The strain gauge 108 is directly connected to the notch 106 to absorb the deflection of the beam 102. The wire 110 is connected to the strain gauge 108 which transmits the changes in resistance of the strain gauge 108 to a Wheatstone bridge (not shown in FIG. 1).

[0009] FIG. 2 is a flow diagram illustrates the working procedure of the hand grip dynamometer 100 of FIG. 1 according to an embodiment herein. At step 202, the user can apply their force / grip strength / pinch force by aligning the fingers of the user with the impression given in the enclosure of the hand grip dynamometer 100, which in turn act as a load for the beam. At step 204, due to geometry of the beam, the beam gets deflected with respect to the user applied force/grip strength which in turn induces the bending strain at notch region of the beam. Due to the bending strain in the beam, the strain gauge 108 gets deformed at step 206. At step 208, due to deformations, the change in resistance of the strain gauge occurs which results in unbalanced voltage of the Wheatstone bridge at step 210.

[0010] The weak unbalanced voltage is amplified at step 212 in order to send the amplified signal to an analog to digital converter (ADC). At step 214, the amplified voltage will be given to the Analog to Digital converter to covert the analog signal from sensor and the Wheatstone bridge to digital signal. At step 216, the digital signal coming out of the ADC will be given to the PIC microcontroller which will be programmed for calibration of the load (i.e., grip strength or pinch force) with respect to the voltage. The digital signal coming out of the PIC microcontroller will be used to show the load values in the LCD display at step 218.

[0011] In one embodiment, the circular rod/beam is made up of aluminum or steel and its geometric form helps to reduce the contact stress by 3.5 times when compare to other conventional designs. In another embodiment, the weight of the hand grip dynamometer 100 is relatively less when compared to existing systems. In one embodiment, the geometry of the circular rod 102 reduces the stress by 2 to 5 times. In another embodiment, the circular rod 102 is of a diameter that ranges from 10mm to 40mm and a length that ranges from 80mm to 160mm in size. In yet another embodiment, width of the slot ranges from 1mm to 10mm and cuts longitudinally for a depth that ranges from 50mm to 110mm in the circular rod 102. The diameter of the notch ranges from 10mm to 30mm and depth of the notch on each side of the beams (e.g., the beams 102) ranges from 5mm to 15mm.

[0012] The foregoing description of the specific embodiments will so fully reveal the general nature of the embodiments herein that others can, by applying current knowledge, readily modify and/or adapt for various applications such specific embodiments without departing from the generic concept, and, therefore, such adaptations and modifications should and are intended to be comprehended within the meaning and range of equivalents of the disclosed embodiments. It is to be understood that the phraseology or terminology employed herein is for the purpose of description and not of limitation. Therefore, while the embodiments herein have been described in terms of preferred embodiments, those skilled in the art will recognize that the embodiments herein can be practiced with modification within the spirit and scope of the appended claims.

CLAIMS What is claimed is:

1. An apparatus for measuring a grip strength and a pinch strength applied by a user to a hand grip dynamometer, said hand grip dynamometer comprising:

a circular rod comprising a first beam and a second beam;

a horizontal slot which separates said first beam and second beam;

a notch directly coupled to said first beam and second beam, wherein a strain is induced in atleast one of said first beam and second beam at a region of said notch based on said grip strength and said pinch strength; and

a strain gauge connected to said region of said notch, wherein a resistance of said strain gauge changes due to said induced strain.

2. The apparatus according to claim 1, wherein said apparatus comprising:

a Wheatstone bridge directly connected to said strain gauge through a wire, wherein said Wheatstone bridge generates a signal based on said change in said resistance of said strain gauge, wherein said signal comprises a voltage;

an amplifier to amplify said voltage obtained from said Wheatstone bridge; and

an analog to digital converter that converts said signal to a digital signal.

3. The apparatus according to claim 1, wherein said apparatus further comprises a PIC microcontroller for calibrating a load applied by said user.

4. The apparatus according to claim 1, wherein said apparatus further comprises a LCD display to show a digital value and a load value.

5. The apparatus according to claim 1, wherein a geometry of said circular rod reduces said stress by 2 to 5 times.

6. The apparatus according to claim 4, wherein said circular rod is of a diameter that ranges from 10mm to 40mm and a length that ranges from 80mm to 160mm in size.

7. The apparatus according to claim 1, wherein a width of said slot ranges from 1mm to 10mm and cuts longitudinally for a depth that ranges from 50mm to 110mm in said circular rod.

8. The apparatus according to claim 1, wherein a diameter of said notch ranges from 10mm to 30mm and a depth of said notch on each side of said first beam and second beam ranges from 5mm to 15mm.