FORCE-MEASURING APPARATUS

Abstract

The invention relates to apparatus to be worn at or adjacent to the knee joint of a person to detect the impact effect of forces applied to the knee joint and, as a result of the detection, and typically analysis of information relating to the person wearing the apparatus, feedback information is provided to the person, in one embodiment during the time when the apparatus is being worn, so as to provide timely feedback to the person wearing the apparatus of the impact on the PF joint. The person wearing the apparatus or monitoring the same can use the feedback whilst the apparatus is being worn, in order to allow the person to change their movement or stop their movement with immediate effect and thereby prevent or minimise the risk of the injury occurring.

Claims

1: An apparatus for detecting and measuring one or more forces exerted on, or adjacent to, a joint of a person's knee, wherein said apparatus includes a sensing means for detecting and measuring at least one property of said exerted force; power supply means: and data processing means connected to, or included with, the said sensing means which is worn by the user at, or adjacent to, the said knee during use, the apparatus provides feedback information to the person and/or another person in relation to the measured force and/or the impact effect exerted on the said knee joint wherein the apparatus includes a reminder system to generate feedback to confirm when a correct gait is adopted by the user or warn of the danger of the user's gait causing the force impact effect to be beyond a predetermined threshold value

2: Apparatus according to claim 1 wherein the feedback includes information provided to assist in the person taking preventative action to reduce the risk of injury to the said knee joint.

3: Apparatus according to claim 1 wherein the apparatus includes data transfer means to allow the feedback information to be provided.

4: Apparatus according to claim 3 wherein said data transfer means permit transfer of data to and from the apparatus.

5: Apparatus according to claim 1 wherein the feedback information is provided to the person during the time when the apparatus is being worn and is in use.

6: Apparatus according to claim 5 wherein the feedback information provided when the apparatus is being worn allows the person to change their movement at that time to reduce the risk of injury or stop their movement with immediate effect and thereby prevent or minimise the risk of injury occurring.

7: Apparatus according to claim 1 wherein specific information relating to the person using the apparatus is input to the apparatus prior to and/or during use.

8: Apparatus according to claim 7 wherein the said information is referred to in the calculation of the impact effect of forces measured as being exerted on the said knee joint.

9: Apparatus according to claim 1 wherein the calculated impact effect is compared to a predetermined threshold value beyond which damage to the knee joint may be caused.

10: Apparatus according to claim 1 wherein the apparatus includes alert means which activate when the calculated impact effect matches or exceeds the predetermined threshold value.

11. (canceled)

12: Apparatus according to claim 1 wherein the sensing means is located on a strap which is selectively positioned at or adjacent to the person's knee.

13: Apparatus according to claim 12 wherein the sensing means is provided at a predetermined location with respect to the strap, and hence the person's knee, when worn.

14: Apparatus according to claim 1 wherein the sensing means is a three-axis accelerometer.

15: Apparatus according to claim 1 wherein said sensing means detects and measures at least two forces when exerted on the user along orthogonal axes.

16: Apparatus according to claim 15 wherein the apparatus evaluates the impact effect of forces exerted laterally on the knee joint.

17: Apparatus according to claim 1 wherein a plurality of sensing means are provided in the apparatus and are located at spaced locations substantially around the knee joint of a user, when the apparatus is worn.

18: Apparatus according to claim 1 wherein the data processing means include a micro controller unit (MCU), memory, and timer.

19: Apparatus according to any of the preceding claims wherein the said knee joint is the patellofemoral joint.

20: A method of monitoring the force exerted on at least one joint of a knee, said method comprising the steps of mounting a three-axis sensing means via a mounting means at or adjacent to the said knee joint, to measure the amplitude and direction of forces applied to the said joint, transmitting data via data processing means which is representative of the said measured force, calculating the impact effect of the measured forces exerted on the said joint with reference to information specific to the person whose knee is being monitored and generating feedback to confirm when a correct gait is adopted by the user or to alert of the danger of the users gait causing the force impact effect to be beyond a predetermined threshold value if the calculation indicates that the impact effect exceeds a predetermined threshold value.

21: A method according to claim 20 wherein the alert is any, or any combination, of audible (speaker), visual (LED) and/or a motional (vibrator) alert.

22: A method according to claim 21 wherein the information relating to the person is provided via a wireless radio frequency (RF) transmitter from a mobile peripheral device (105).

23: A method according to claim 20 wherein the sensing means measure the direction and amplitude of one or more forces exerted.

Description

[0036] Embodiments of the present invention will now be described with reference to the accompanying figures, wherein:

[0037] FIG. 1 shows a flow diagram of the method of operation of the apparatus in accordance with an embodiment of the present invention;

[0038] FIG. 2 shows an electronic component of an apparatus in accordance with an embodiment of the present invention;

[0039] FIGS. 3a- c show the (a) rear view, (b) side view and (c) front view of an apparatus in accordance with an embodiment of the present invention;

[0040] FIGS. 4a- b describe the measurement of impact effect on (a) a person running in side view and (b) a person running in front view and wearing an apparatus in accordance with an embodiment of the present invention; and

[0041] FIGS. 5a-c illustrate an embodiment of apparatus in accordance with the invention.

[0042] Referring firstly to FIG. 1, the flow diagram demonstrates the method workflow in accordance with the present invention. There is provided sensing means in the form of a three-axis accelerometer (102) provided to be mounted with respect to the joint of a person via a physical attachment (101), which, most typically, is provided in the form of a knee band to be worn by a person either on, just below or just above the knee joint which is to be monitored.

[0043] The accelerometer measures the force amplitude and direction which his impacted on the knee joint with respect to which the apparatus is mounted. Data representative of the measured force is transmitted via data processing means in the form of an integrated circuit (104) which includes a memory, timer and Micro Controller Unit (MCU). The power supply (103) supplies power to the electronic timer/controller integrated circuits and MCU. The MCU calculates the impact effect of the various forces which are detected by the accelerometer 102 as having been exerted on the knee joint.

[0044] If the impact effect on the joint, such as the patellofemoral joint (PF joint), is calculated to have exceeded a predetermined threshold then action can be taken.

[0045] Typically the impact effect is calculated with reference to information which is specific to the person, such as their weight, height, heart rate, BMI and other physical and/or social and/or environmental factors. This information is typically input to the MCU prior to and/or during the wearing and use of the apparatus via module 105.

[0046] In the event that the predetermined threshold value is exceeded by the calculated impact effect then one of the actions can be the generation of an alert by an information output module (106), and the alert can be any or any combination of audible (speaker), visual (LED) and/or a motional (vibrator) alert.

[0047] The information to and from the respective modules 105, 106 can be transmitted via a wireless radio frequency (RF) transmitter (e.g. Bluetooth) from a mobile peripheral device (105). In one embodiment part of the information is used to assess the force exerted above the PF joint. Additionally, the information can be stored in memory means provided in the mobile peripheral (106) and is accessible over a period of time as a tool for tracking the history of the impact effect and alerts generated for the person wearing the apparatus.

[0048] FIG. 2 illustrates the mounting means (101) in the form of a knee strap and/or a belt adapted to encircle the leg at the region of the knee. Typically the strap has sufficient elasticity or is sufficiently tight to thereby retain the same in position. Electronic components of the apparatus such as the power supply means, data processing means, alert means and information output and input modules (203) are located at the front part of the strap when worn. The accelerometer (102), in the form of a three-axis accelerometer to detect direction and amplitude of the force exerted on the PF joint is provided on the strap. Additional accelerometers and/or other sensing components may be located within the strap (101) at points located around the knee joint. The power supply contains battery (103) to supply power to the electronic circuits. In addition, an external power supply with an AC to DC converter may also be provided.

[0049] In order to notify the user if and when a predetermined impact effect threshold value is met or exceeded, the alert means can be operated in one or a combination of various forms: a motor (202) generates a vibration to alert the user and, additionally, a wireless alert signal may be provided. The alert is transmitted to a peripheral device, e.g. mobile phone or Bluetooth headphone and an audible alert may be activated in the form of a beep, alarm etc.

[0050] Within the integrated circuit (104) of the apparatus, the MCU implements algorithms to process input information and generate output information. Also included can be a sensor input circuit; timer circuitry; a memory circuit; an alert function, driver circuit for a vibrator, speaker etc.; and wireless radio frequency (RF) transmitter circuitry to allow remote information access are also included.

[0051] Referring to FIGS. 3a-c, the mounting means (101) is shown as being adapted to encircle the leg at the PF joint region, and therefore may encircle the top and/or bottom part of the joint. The mounting means can include a buttress support at the rear when it is worn. The electronic components (203) are shown located with the mounting means (101) at a fixed location, although this need not be restricted to the centre of the belt (101) facing outward, as shown in the present figures.

[0052] FIG. 4 describes the measurement of the effect of impact by forces on a person's 110 knee joint 112 on their leg 114 at a side view (FIG. 4a) and a front view (FIG. 4b) as they are running along a surface 116. In the case of normal running gait, the magnitude of the impact effect, which is proportional to the acceleration upon impact (shown as the solid arrow 118), is the major factor that causes damage and/or pain to the knee joint. The horizontal component of the force 120 in the x-axis corresponds to sideway force imparted on the PF joint 112, which is the cause of misalignment that, in turn, contributes to knee damage.

[0053] FIGS. 5a-c illustrate apparatus 100 in a form to be worn. The apparatus includes a strap 102 which in this case has a hook and loop fastening arrangement so as to allow the ends 104-106 of the same to be brought into engagement at a location which allows the strap to be closely fitted in position around the person's leg at or adjacent to the knee joint, and be retained in that position during use.

[0054] The strap includes an aperture 108 in which is located the sensing means 110 in the form of an accelerometer. Although in this example there is only provided one sensing means it should be appreciated that in other embodiments a plurality of accelerometers can be provided at spaced locations. The accelerometer 110 is mounted on a support 112 and the accelerometer 110 is placed into the apertures 108 to be retained therein.

[0055] The support 112, processing means circuit 114 and power supply 116 are all located on a backing layer 118 which is attached to the inner surface 120 of the strap so that the same are effectively sandwiched between the strap 102 on one side and the backing layer 118 on the other side and thereby protected from damage when being worn.

[0056] Thus, the apparatus of the present invention provides a wearable device that contains a number of sensing means which measure the direction and amplitude of one or more forces exerted on, for example, the knee of a user during running exercise and footwork, and consequently provides feedback based on previously input information of weight, height etc. of the user. The information is processed by data processing means within the apparatus and analysed in relation to personal data of the user to provide customised feedback. The feedback can be presented in various forms such as instant notification and wireless transmission of data for further analysis, in order to help the user to attain or maintain the desired running gait and footwork to avoid knee injury.