WO2019241824A1 - Cellule de charge portable - Google Patents

Cellule de charge portable Download PDF

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Publication number
WO2019241824A1
WO2019241824A1 PCT/AU2019/000078 AU2019000078W WO2019241824A1 WO 2019241824 A1 WO2019241824 A1 WO 2019241824A1 AU 2019000078 W AU2019000078 W AU 2019000078W WO 2019241824 A1 WO2019241824 A1 WO 2019241824A1
Authority
WO
WIPO (PCT)
Prior art keywords
load cell
arm
recess
load
portable
Prior art date
Application number
PCT/AU2019/000078
Other languages
English (en)
Inventor
Lyndon HUF
Mohammad Sharif UDDIN
Alec BRYCE
Alexander William Walker
Original Assignee
Maction Pty Ltd
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Priority claimed from AU2018902252A external-priority patent/AU2018902252A0/en
Application filed by Maction Pty Ltd filed Critical Maction Pty Ltd
Publication of WO2019241824A1 publication Critical patent/WO2019241824A1/fr

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Classifications

    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01L—MEASURING FORCE, STRESS, TORQUE, WORK, MECHANICAL POWER, MECHANICAL EFFICIENCY, OR FLUID PRESSURE
    • G01L5/00—Apparatus for, or methods of, measuring force, work, mechanical power, or torque, specially adapted for specific purposes
    • G01L5/04—Apparatus for, or methods of, measuring force, work, mechanical power, or torque, specially adapted for specific purposes for measuring tension in flexible members, e.g. ropes, cables, wires, threads, belts or bands
    • G01L5/045—Apparatus for, or methods of, measuring force, work, mechanical power, or torque, specially adapted for specific purposes for measuring tension in flexible members, e.g. ropes, cables, wires, threads, belts or bands for measuring the tension across the width of a band-shaped flexible member
    • A—HUMAN NECESSITIES
    • A63—SPORTS; GAMES; AMUSEMENTS
    • A63B—APPARATUS FOR PHYSICAL TRAINING, GYMNASTICS, SWIMMING, CLIMBING, OR FENCING; BALL GAMES; TRAINING EQUIPMENT
    • A63B24/00—Electric or electronic controls for exercising apparatus of preceding groups; Controlling or monitoring of exercises, sportive games, training or athletic performances
    • A63B24/0062—Monitoring athletic performances, e.g. for determining the work of a user on an exercise apparatus, the completed jogging or cycling distance
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01L—MEASURING FORCE, STRESS, TORQUE, WORK, MECHANICAL POWER, MECHANICAL EFFICIENCY, OR FLUID PRESSURE
    • G01L1/00—Measuring force or stress, in general
    • G01L1/20—Measuring force or stress, in general by measuring variations in ohmic resistance of solid materials or of electrically-conductive fluids; by making use of electrokinetic cells, i.e. liquid-containing cells wherein an electrical potential is produced or varied upon the application of stress
    • G01L1/22—Measuring force or stress, in general by measuring variations in ohmic resistance of solid materials or of electrically-conductive fluids; by making use of electrokinetic cells, i.e. liquid-containing cells wherein an electrical potential is produced or varied upon the application of stress using resistance strain gauges
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01L—MEASURING FORCE, STRESS, TORQUE, WORK, MECHANICAL POWER, MECHANICAL EFFICIENCY, OR FLUID PRESSURE
    • G01L5/00—Apparatus for, or methods of, measuring force, work, mechanical power, or torque, specially adapted for specific purposes
    • G01L5/04—Apparatus for, or methods of, measuring force, work, mechanical power, or torque, specially adapted for specific purposes for measuring tension in flexible members, e.g. ropes, cables, wires, threads, belts or bands
    • G01L5/10—Apparatus for, or methods of, measuring force, work, mechanical power, or torque, specially adapted for specific purposes for measuring tension in flexible members, e.g. ropes, cables, wires, threads, belts or bands using electrical means
    • G01L5/101—Apparatus for, or methods of, measuring force, work, mechanical power, or torque, specially adapted for specific purposes for measuring tension in flexible members, e.g. ropes, cables, wires, threads, belts or bands using electrical means using sensors inserted into the flexible member
    • A—HUMAN NECESSITIES
    • A63—SPORTS; GAMES; AMUSEMENTS
    • A63B—APPARATUS FOR PHYSICAL TRAINING, GYMNASTICS, SWIMMING, CLIMBING, OR FENCING; BALL GAMES; TRAINING EQUIPMENT
    • A63B21/00—Exercising apparatus for developing or strengthening the muscles or joints of the body by working against a counterforce, with or without measuring devices
    • A63B21/02—Exercising apparatus for developing or strengthening the muscles or joints of the body by working against a counterforce, with or without measuring devices using resilient force-resisters
    • A63B21/055—Exercising apparatus for developing or strengthening the muscles or joints of the body by working against a counterforce, with or without measuring devices using resilient force-resisters extension element type
    • A63B21/0552—Elastic ropes or bands

Definitions

  • the present disclosure relates to load cells.
  • the present disclosure relates to a portable load cell for health, fitness, training, well-being, aquaculture, agriculture applications.
  • Clinicians such as physiotherapists and occupational therapists are interested in assessing muscle weakness in patients and often prescribe exercises using resistance band or cord type devices such as cables to rebuild muscle strength.
  • the patient fixes one end of the elastic band to a fixed support and grasps a handle formed in, or connected to the other end of the resistance band and performs a set of exercises at the home, clinic or a gym.
  • Clinicians assess recovery at subsequent consultations.
  • clinicians would also like to measure additional information such as the adherence of the patient to the exercise regime, and the actual force exerted by the patient during use, so that this can be tracked over an extended time period order to make an a more informed assessment of the patient’s recovery and to adjust treatment as required.
  • a portable load cell based system for home and out of clinic use needs to be robust, compact, reliable, easy to attach and detach, and preferably low cost.
  • the system must be sufficiently sensitive over a range from lOOg up to lOOkg of axial force (and potentially up to 400kg or more as an appropriate safety margin).
  • the system must also be able to function repeatedly and reliably, and also be repeatedly attached and detached. For example in a high volume setting such as a sporting team, 50 players may use the apparatus 48 weeks a year , each using the apparatus for 3 sets of 5 exercises, 3 times per week on each side, leading to 216,000 uses per year and 72,000 attachments/detachments.
  • the system must be robust enough to withstand the rigours of accidental drops, from a height such as l-2m. A drop from that height can potentially overload the load cells electrical and mechanical properties leading to damaging the ability to measure accurately for which it was designed.
  • the load cell should be designed to protect the load cell from these damaging forces of either a single large or plurality of smaller instances. Further the system needs the ability to communicate results to other apparatus and systems to enable reporting to clinicians and users.
  • a portable load cell apparatus comprising:
  • a load cell body having a central portion, a first clip portion at a first end and a second clip portion at a second end, each of the first and second clip portions comprising a hook portion, a connecting portion and an arm defining a clipping cavity and each arm is connected to the central portion via a spring hinge configured to allow the arm to be deflected inwards towards the connecting portion to provide access to the clipping cavity and the arm is biased to resiliently return the arm towards the hook portion to close the clipping cavity, wherein an end of the hook acts as stop to prevent outward deflection of the arm;
  • a cover comprising a first side portion and a second side portion , wherein the first and second side portions each at least partially extend over each spring hinge to prevent transverse movement of the arm;
  • a load cell located in the central portion and comprising at least one strain gauge sensor configured to measure strain along at least one surface of the load cell as a load is applied to the apparatus via the first clip portion and the second clip portion;
  • the connecting portion may have an inclined inner surface and when the arm is in the fully deflected inward position an inner surface of the arm contacts an inner surface of the connecting portion, wherein the inner surface of the connection portion has a profile matching the inner surface of the arm so as to maximise access to the clipping cavity.
  • an inner surface of each hook portion may have a self-centring profile comprised of a rounded arrowhead formed from two linear inclined surfaces.
  • each spring hinge may be a serpentine spring comprised of a plurality of connected transverse linear members which form a serpentine path.
  • a gap between the adjacent transverse linear members may be constant, and an axial thickness of each of the transverse linear members decreases from a first linear member proximal to the central portion to a last linear member most distal from the central portion.
  • each of the transverse linear members may be joined by U shaped ends and under full deflection adjacent linear members do not touch.
  • the thickness of the first linear member may be 0.60mm and the thickness of the last linear member may be 0.50mm.
  • the serpentine spring may comprise 8 linear members with progressive thicknesses of 0.6, 0.58, 0.55, 0.55, 0.52, 0.52, 0.5 and 0.5mm, and the gap between adjacent members is 0.8mm.
  • load cell body may be formed from a single piece of material.
  • the load cell body is formed from a titanium alloy.
  • the body is formed from Ti-6A1-4V.
  • the load cell body is formed of a material with a modulus of elasticity of lOOGPa or more.
  • the load cell body has a yield point of at least 5000N.
  • the one or more strain gauges generate strains proportional to the axial load for axial loading of up to 1000N of axial force.
  • the central portion may comprise a central cavity defined by two axial beams and two transverse surfaces, and at least one strain gauge sensor is located on at least one transverse surface.
  • the at least one strain gauge sensor comprises four strain gauge sensors arranged in a full Wheatstone Bridge circuit located on one of the transverse surfaces.
  • the load cell body further comprises a switch formed from an arm and a switch cavity, the switch cavity comprises a switch actuator and a channel, wherein the arm defines one side of the channel and has a channel length lOmm, a thickness of 0.5mm a channel gap of 0.8mm, and an end of the arm extends beyond the channel to substantially close the switch cavity, and comprises an inwardly directed boss, such that lateral actuation of the arm moves the boss towards the switch actuator.
  • the load cell body is formed using a Wire EDM cutting process.
  • the apparatus may further comprise a first recess and a second recess located at opposed ends of the central portion of the load cell, and a first shock absorbing material located in the first recess and a second a second shock absorbing material located in the second recess.
  • each of the first recess and the second recess may comprise a laterally extending U shaped cut out further comprising a retaining recess and the first and second shock absorbing material each comprise a rib that is received in the retaining recess.
  • At least one of the shock absorbing material may be formed of a transparent or translucent material configured as a light pipe
  • the electronic module comprises one or more LEDs and is configured to send status signals to the one or more LEDS, and wherein one end of the light pipe is externally visible surface and the light pipe is configured to direct light from the one or more LEDs to the externally visible surface.
  • the electronic module may be configured to generate an alarm signal if the load cell measurement exceeds a predefined threshold wherein the alarm signal is used to generate an audio alarm via an audio interface and/or a visual alarm via a visual indicator.
  • the visual indicator may be a LED incorporated in the apparatus.
  • a portable load cell apparatus comprising:
  • a load cell body having a first attachment portion at a first end and a second attachment portion at a second end, each of the first and second attachment portions configured to allow attachment of the load cell body to an external support;
  • a load cell located between the first attachment portion and the second attachment portion and comprising at least one strain gauge sensor configured to measure strain along at least one surface of the load cell as a load is applied to the apparatus via the first attachment portion and the second attachment portion;
  • first shock absorbing material located in the first recess and a second a second shock absorbing material located in the second recess;
  • each of the first recess and the second recess may comprise a laterally extending U shaped cut out further comprising a retaining recess and the first and second shock absorbing material each comprise a rib that is received in the retaining recess.
  • the at least one of the shock absorbing material may be a formed of a transparent or translucent material configured as a light pipe
  • the electronic module may comprise one or more LEDs and is configured to send status signals to the one or more LEDS, and wherein one end of the light pipe is externally visible surface and the light pipe is configured to direct light from the one or more LEDs to the externally visible surface.
  • a system for visualising a load measurement comprising:
  • a computing apparatus comprising at least one processor, a memory, a display and a
  • the at least one processor is configured to receive load cell measurements from the portable load cell apparatus via the communications interface, and to display a visual representation of the received load cell measurements as a function of time via the display.
  • the communications interface may be a wireless communications interface
  • the load cell measurements may be received from the load cell apparatus and displayed in real time or near real time
  • the computing apparatus may be configured to receive an alarm signal indicating the load cell measurement has exceeded a predefined threshold, and generating an audio alarm via an audio interface and/or visual alarm via the display.
  • kits comprising:
  • a plurality of extension apparatus each configured to receive one or more of the one or more portable load cell apparatus, and comprising one or more movable surfaces such that in use movement of one or more movable surfaces generates a load on the portable load cell apparatus.
  • The may further comprise a computer program product comprising instructions to cause a computing apparatus to receive load cell measurements from the portable load cell apparatus, and to display a visual representation of the received load cell measurements as a function of time.
  • Figure 1A is a perspective view of a portable load cell according to an embodiment
  • Figure IB is a schematic side view of the portable load cell body of Figure 1A with side covers removed;
  • Figure 1C is an end view of a light pipe arrangement according to an embodiment
  • Figure ID is a side view of a light pipe arrangement according to an embodiment
  • Figure 1 E is a top view of a light pipe according arrangement to an embodiment
  • Figure 2A is a schematic close up view of a serpentine spring according to an embodiment
  • Figure 2B is a schematic close up view of a serpentine spring with dimensions according to an embodiment
  • Figure 2C is a schematic view of a FEA simulation of stress in the serpentine spring of the portable load cell body according to an embodiment
  • Figure 3 is a schematic diagram of a load cell body indicating dimensions for yield point measurements according to an embodiment
  • Figure 4A is a top view of a sideways deflection of a serpentine spring
  • Figure 4B is a perspective view of a serpentine spring with side covers to prevent the sideways deflection shown in Figure 4A;
  • Figure 4C is a perspective view of the interior of a cover according to an embodiment
  • Figure 5 A is a schematic close up view of a switch according to an embodiment
  • Figure 5B is a schematic close up view of a switch with dimensions according to an embodiment
  • Figure 5C is a schematic view of a FEA simulation of stress in the switch of the portable load cell body according to an embodiment
  • Figure 6A is a plot of a FEA simulation of strain in the normal Y direction under a 1000N load in the X (axial) direction of a portable load cell body according to an embodiment
  • Figure 6B is a plot of a FEA simulation of the displacement in the X (axial) direction under a 1000N load in the X (axial) direction in the portable load cell body of figure 5A;
  • Figure 6C is a plot of a FEA simulation of stress under a 1000N load in the X (axial) direction in the portable load cell body of figure 5A;
  • Figure 7 is a schematic diagram of an electronics module according to an embodiment
  • Figure 8A is an exploded view of another embodiment of a portable load cell apparatus comprising a removable spring arm
  • Figure 8B is a side view of the load cell body of the embodiment shown in Figure 8A;
  • Figure 8C is a perspective view of another embodiment of a portable load cell apparatus comprising a spring arm formed using a curved slot;
  • Figure 9A is a side view of a portable load cell apparatus comprising a two part body housing a sensor link member according an embodiment
  • Figure 9B is an isometric view of the portable load cell apparatus shown in Figure 9A;
  • Figure 10A is a schematic diagram of a system for visualising a load cell measurement according an embodiment.
  • Figure 10B is a side view of an dynamometer extension apparatus according an embodiment
  • Figure 10C is a side view of an extension apparatus for groin adduction/abduction incorporating the dynamometer extension apparatus of figure 10B according to an embodiment
  • Figure 10D is an top view of the inner side groin adduction/abduction plate of Figure 10C;
  • Figure 10E is an top view of the dynamometer extension apparatus of Figure 10B and 10C;
  • Figure 1 OF is a side view of a force plate extension apparatus incorporating four dynamometer extension apparatus of Figure 10B according to an embodiment
  • Figure 10G is a top view of the inner surface of the force plate extension apparatus of Figure 10F incorporating four dynamometer extension apparatus of Figure 10B;
  • Figure 1 OH is a side view of a curved force plate extension apparatus incorporating triangulated dynamometer extension apparatus of Figure 10B according to an embodiment
  • Figure 101 is a top view of the curved force plate extension apparatus of Figure 10F incorporating triangulated dynamometer extension apparatus of Figure 10B;
  • Figure 10J is perspective view of a tower-frame extension apparatus and associated connection apparatus incorporating load cell apparatus according to an embodiment.
  • FIG. 1 A there is shown a perspective view of a portable load cell apparatus according to an embodiment.
  • the load cell apparatus comprises a load cell body 2 having a central portion 103 and a first end 8 and a second end 1 1 which defines the axis (and axial direction) of the load cell body.
  • a removable attachment portion is formed in each end.
  • each of the first and second attachment portions 101 102 are carabiner like clip portions to allow removable attachment of the load cell body 2 to an external support.
  • Each clip portion comprises a hook portion 27, 39, a connecting portion and an arm 6, 9 defining a clipping cavity and each arm 6, 9, is connected to the central portion 103 and comprises a spring hinge 7, 10 configured to allow the arm 6, 9 to be deflected inwards towards the connecting portion 43 to provide access to the clipping cavity and the arm 6, 9 is biased to resiliently return the arm towards the hook portion 27, 39, to close the clipping cavity, wherein an end of the hook acts as stop to prevent outward deflection of the arm.
  • a pair of covers 3 hides a load cell 22 located between the first attachment (or clip) portion 101 and the second attachment (or clip) portion 102 and prevents transverse movement of each arm 6, 9.
  • the load cell comprises four strain gauge sensors 23 arranged in full
  • Wheatstone bridge configuration located on one side 24 of the load cell (one of the attachment sides) and configured to measure strain along at least one surface of the load cell as a load is applied to the apparatus via the first attachment portion and the second attachment portion. For example as the load cell is pulled axially via the clips during exercises a strain will be imparted to the device in a transverse direction to the axial load, and the strain gauges are placed in a location to detect and measure this strain.
  • the strain gauges may be attached by bonding using a suitable glue or attachment process (typically defined by the strain gauge manufacturer). In another embodiment the strain gauges may be soldered or welded in place using laser welding or ultrasonic welding.
  • An electronics module 700 is located within the covers 3 and is configured to measure a load cell measurement from the load cell 22 and store or wirelessly transmit the load cell measurement or a force related measurement based on the load cell measurement to an external device.
  • the load cell apparatus further comprises a switch 4 and one or more status indicators 5, which in this embodiment are located on the load cell body 2, and which are connected to and form part of the electronics module 700. In other embodiments the switch and status indicator could be provided in the covers 3.
  • the location of the switch 4 defines an orientation of the load cell body.
  • the first end 8 is proximal to the switch 4 and the second end 11 is distal of the switch 4. In this embodiment the first end is attached to handle (ie first end proximal to switch 4) and the second end is attached to the resistance band (ie the second end is distal to the switch 4).
  • the load cell apparatus described herein is designed for measuring muscle weakness for medical, rehabilitation and sporting science applications.
  • the apparatus may be placed in line between a support and an elastic resistance band (Theraband) to measure the magnitude of the total axial force as the patient pulls the elastic resistance band to perform an exercise (ie magnitude of total or unidirectional force applied or travelling through the apparatus).
  • the load cell uses sensitive strain gauges 23 which translate the strain on the apparatus to a change in resistance of the gauge, which translates to a change in a voltage, which through calibration of the apparatus can then be mapped to the force being applied by the user.
  • the measured load or force is relayed to the user, preferably as real-time feedback by visual indicator 5.
  • the measured load or force is sent over a communication link to a software app that receives the data.
  • the data may be displayed in real-time and/or stored for later review.
  • the data may be sent over the communication link in real time or the apparatus may store the data before uploading to the software app for later.
  • the load cell apparatus may be used with other extension (or exercise) apparatus that comprise one or more movable surfaces such that in use movement of one or more movable surfaces generates a load on the portable load cell apparatus.
  • FIG. 1B is a schematic side view of the portable load cell body of Figure 1 A with side covers 3 removed.
  • the centre of the load cell body comprises a load cell 22 comprising a central cavity 21 defined by two opposing axial beams 25 and 26 and two opposing transverse surfaces 24 and 24'.
  • At least one strain gauge sensor 23 is located on one of the transverse surfaces 24, 24'.
  • Strain gauge sensors can also be located on both transverse surfaces, although it noted that this doubles the power requirements of the system.
  • the measured strain is then translated into a change in resistance of the strain gauges that are installed at the location of the isolated strain point (on the surface).
  • this resistance change will then change the voltage of the circuit.
  • the change in voltage and the load placed on the apparatus will be proportional. This means the load can be calibrated through calculations done in the firmware of the apparatus and the correct and accurate force readings will be displayed back to the user.
  • One, two or four strain gauge sensors may be used for each Wheatstone Bridge circuit (ie quarter, half or full bridges).
  • the attachment portions are formed as hooks in which curvature of the hook allows for an external attachment such a band or cable.
  • the axial line of force 70 is defined by the line joining the lowest point (radii) of each hook, and the strain gauges 23 are located so that the line of force 70 passes through the centre of the stain gauges.
  • the inner surface of each hook portion has a self centering profile. This self-centering profile maximises the axial loading (x-direction) and minimises any unwanted y or z vectors.
  • This approach allows the line of force under axial loading to self-align so that the line of force from one hook end to the other goes through the point where maximum strain is being measured and hence maximises a strain measurement while minimising unwanted offsets in other directions.
  • the self-centering profile is comprised of a rounded arrowhead formed from two linear inclined surfaces as shown by dotted lines 71 72 in Figure 1 B, where the rounded arrowhead acts a notch in which a connecting cable will locate.
  • the apparatus is designed for use up to axial loads of about lOOkg.
  • the apparatus should function correctly (ie without failing) at higher loads, for example applying a factor of safety (FOS) of 4 provides a maximum force of 400kg. Additionally the apparatus should be able to read force measurements as small as 1 OOg. To meet these operational requirements sensitive strain gauges need to be used. However a potential downside is that the strain gauges (and the load cell as a whole) are sensitive to shocks and accidental drops which may overload and affect the sensitivity, accuracy or calibration of the strain gauges/load cell.
  • FOS factor of safety
  • the load cell body 2 further comprises a first recess 19 and a second recess 20 located at opposed ends of the load cell, and a first shock absorbing material is located in the first recess 19 and a second a second shock absorbing material located in the second recess 20.
  • each of the recesses are diametrically opposed and have an identical U shaped profile (when viewed from the side as in Figure 1 B), but in other embodiments other shapes could be used such as half circle, rectangle, wedge, and regular or irregular polygonal.
  • the recesses and shock absorbing materials are designed to protect the load cell by withstanding the compression forces from either a single large or plurality of smaller shocks that could otherwise exceed the load cells mechanical properties, or otherwise affect the ability to measure accurately and repeatedly during the life of the apparatus.
  • the shock absorbing material may be constructed from various rubber, plastics, or other materials with similar resilient shock absorbing properties. Transparent visco-elastic polymers such as silicone or polycarbonate can be used to absorb the impact energy generated during shock and will deform converting kinetic energy of shock into heat energy, which will then dissipate.
  • the shock absorbing material has the effect of lowering the peak force experienced by the apparatus.
  • the two recesses 19, 20 are located at diametrically opposed ends of the load cell. This provides an efficient and cost effective way to provide shock protection.
  • more than two recesses (3, 4, 5, 6, etc) could be provided, and they may be provided in other locations. For example rather than using 1 large recess at either end of the load cell, 2 or 3 smaller recesses could be provided.
  • recesses could be provided near each corner of the load cell, rather than just the diagonally opposed corners.
  • these more complex arrangements and locations are in most cases less desirable as they required additionally cutting (adding to cost, additional components and device complexity) and require more careful design analysis to ensure they do not adversely affect the mechanical strength or sensitivity of the load cell measurements when the apparatus is under load.
  • the shock absorbing material is a translucent or transparent plastic polycarbonate which is also configured to act as a light conductor to provide the visual status indicator 5 (either one or both may be configured as light pipes).
  • Figures 1C, ID and 1E show end, side and top views of a light pipe arrangement 18 according to an embodiment.
  • each light pipe 18 is formed as a wedge shape with a flat surface over one or more LEDs 49 which reflects light towards an end surface 47.
  • the light pipe is shaped to sit within the U shaped cut-out ( 19, 20) and to fill the end near the surface of the load cell body so that the end surface 47 is flush with the surface of the load cell body 2 so that the end surface 47 is externally visible.
  • each U shaped cut-out (19,20) further comprises a retaining recess 45 and the light pipe comprises a rib 46 that is received in the retaining recess 45 to retain the light pipe in place.
  • the light pipe arrangementl8 is shaped to fully fill the U shaped cut-out (19, 20). This arrangement conveniently combines two components, namely the status indicator and overload protection. The arrangement optimises space which is at a premium in a compact apparatus, allows users to view the load cell desired force from different positions, is aesthetically pleasing, follows good design principles of part count reduction and usability, protects the apparatus from damage and allows accurate measurement of force.
  • the light pipe retaining recesses 45 use their geometry and position to improve the factor of safety of the whole device.
  • the location of the light pipe retaining recesses 45 is located near the transverse edge so that stress created by these recesses is redistributed across the whole device and does not affect the strain and displacement measurements of the sensor 23. This also allows self-aligned axial loading as discussed above, leading to more accurate measurements.
  • the load cell body 2 comprises boss receiving apertures 16 and 17 located at either ends of the load cell body.
  • the covers 3 are attached to the load cell body 2 via bosses formed in the inside surface of the covers 3 and which are received in these boss receiving apertures 16 and 17. Other arrangements can also be used to attach the covers to the load cell body such as screws or other fasteners that pass through the boss receiving apertures (16, 17). Electronics and other cables may also pass through the boss receiving apertures to connect electronic components housed in one cover to components housed in the other cover.
  • the covers are constructed from polycarbonate but in other embodiments any suitable material (plastics, metals, etc) may be used that can protect and house the electronics.
  • the cover should be water and sweat resistant and may include a seal to seal the side of the cover against the load cell body and protect the electronics.
  • Various clips and retaining features may be included in the cover to mount the electronics and batteries.
  • Figure 4C shows a perspective view of the inside of a cover 3, showing the side portions 12, a first boss 76 which is received in first boss aperture 16, a second boss 77 which is received in second boss aperture 17, and support structures 78, which support and secure the electronics module 700 to the cover.
  • the load cell apparatus is designed to be removably attached (ie repeatedly detached and reattached) to an external support at one end, and to elastic band such as elastic resistance band at the other, potentially many times per day. Accordingly and as noted above a removable attachment portion is formed in each end.
  • the first attachment portion is a first carabiner like clip portion
  • the second attachment portion is a second carabiner like clip portion.
  • Each of the first and second clip portions comprises a hook portion (27, 39), a connecting portion (104, 105) and an arm (6, 9) defining a clipping cavity.
  • Each arm is connected to the central portion via a spring hinge, which in this embodiment is a serpentine spring (7, 10) which is configured to allow the arm to be deflected inwards (arc 28) towards the connecting portion (104) to provide access to the clipping cavity under a transverse load and biased to return the arm towards the hook portion (27, 39) to close the clipping cavity.
  • the serpentine spring thus acts as spring hinge which pivots around an axis orthogonal to (ie passing through) the load cell body.
  • other spring hinge arrangements may be used to connect the arm to the load cell body whilst providing a biasing force.
  • a split pin hinge arrangement, or slot arrangement (such as that shown in Figure 8A) which may be configured to allow removal and/or replacement of the arm.
  • the arm may be resilient element, or a spring element could be integrated into the arrangement to bias the arm towards the hook.
  • Dotted lines 29 show the outline of the arm 9 when full deflected inwards such that it abuts a matching ramp surface 43 formed in the inner surface of the connecting portion (104, 105) of the load cell body 2.
  • a matching ramp surface 43 formed in the inner surface of the connecting portion (104, 105) of the load cell body 2.
  • the inner surface of the connection portion has a profile matching the inner surface of the arm so as to maximise access to the clipping cavity.
  • the distal end of the hook (39, 27) is inwardly sloped along angle 40 to create a stop surface (ie angled distally from the exterior to interior surface).
  • the distal end of the arm (6, 9) has a matching slope 40.
  • a small gap 41 is formed between the hook end (39, 27) and ends of arms (6, 9). This arrangement acts to stop the clip arm and prevent it from over extending through the clip opening on return from a deflected position.
  • Side covers 3 at least partially extend over each spring hinge to prevent transverse movement of each arm. That is they cover a sufficient portion of the hinge to act as lateral stops or guides to prevent or resist unwanted lateral (out of plane) displacement of the arms. Extending over each spring hinge may mean that they may partially cover each lateral side of the arm (so as to prevent transverse movement of the arm).
  • the covers may be reinforced or formed with reinforcing elements to provide greater lateral resistance.
  • the covers may at least partially cover the lateral side of each arm, including partially covering some proportion of the hinge (or partially extending to cover some proportion of the hinge). For example in the case of a serpentine spring the covers could extend over the first 50% of the serpentine portion (from the central body), or the first 75%.
  • the covers could be shaped as an extended projection which does not cover the full vertical extent of the serpentine spring or hinge (when viewed from the side) but could comprise a bar like extension along the vertical mid-line of the spring hinge. Again this could extend 50% along, 75% along or some other proportion of the spring hinge, including past the spring hinge.
  • the covers could extend fully past the distal end of the hinge or fully cover the hinge when viewed from the side.
  • the cover could comprise of multiple covers, including a pair of covers that over the central cavity and additional covers over the spring hinges. Other variations that cover a portion for the spring hinges to act as a lateral stop are also possible.
  • one or both of the attachment portions are configured as permanent attachment portions, for example as closed loops, or permanently closable loops.
  • a handle could be permanently fitted to a closed loop and the elastic resistance band (or similar elastic member) attached to the other end, or non-elastic members, such as steel cables (for use with gym equipment). These could be used in scenarios where the device is to always be used with a particular piece of equipment or permanently installed at a location.
  • the apparatus is preferably constructed of Titanium alloys, including solution treated and aged Titanium alloys.
  • Alloy Steel, superalloys, thermoplastics, composites or other combination of materials eg sandwiched layers
  • different parts are formed of different materials. Table 1 below provides a comparison between a titanium alloy (Ti-6A1-4V) and Alloy Steel for all the distinct functions required from the hardware for this apparatus for the embodiment shown in Figure 1B based in part of FEA studies. TABLE 1
  • Table 1 shows that the Titanium Alloy functions better than the alloy steel in every aspect required in the apparatus. Therefore, the Ti-6A1-4V was chosen as the material for the hardware. Whilst alloy steel would be cheaper to produce and use for the hardware, the functionality of the apparatus would be reduced as its weight would increase. For example an alloy steel apparatus will under plastic deformation at 298kg compared to 392 kg reducing the factor of safety. Further in embodiments using the serpentine spring (discussed below) the factor of safety is only 1 and it takes twice as much force to bend the spring which may reduce the life of the apparatus. Thus preferably a Titanium Alloy is used as it has very good mechanical strength and elastic properties for the functions desired from the hardware of this product, e.g. being stretched, elongated, bent, pulled, compressed, etc. In one embodiment the Titanium alloy is a Ti-6A1-4V alloy.
  • the spring uses a serpentine spring arrangement which is configured to be easy to open and which springs back to the closed position. Titanium is suitable for this application as it has a high modulus of elasticity (over 1 1 OGPa).
  • Each serpentine spring is comprised of a plurality of transversely extending linear members connected at the ends.
  • Figure 2A is schematic close up view of a serpentine spring according to an embodiment showing the edge thickness 50, gap 51 and thickness 52 of the linear members. The gap is selected to prevent two linear members touching during deflection.
  • a FEA analysis was performed to determine preferred dimensions for the serpentine spring and Table 2 shows the FOS for several configurations.
  • Table 2 illustrates how the FOS changes with the edge thickness. As the edge thickness increases, the bending will be stiffer and harder to perform, leading to increased stress placed on this section.
  • edge thickness is too thin then although it is flimsier and bends more easily, the reduced amount of material is less able to withstand the stress being placed on the U section, and this causes the FOS to decrease. From a review of the table a 0.8mm gap with an edge thickness of 1.1 mm provide the largest FOS.
  • variable thickness embodiment provided the best results.
  • the gap 51 between the linear members is constant, but the thickness (in the axial direction) of the linear members 52 decreases from the end connected to (most proximal to) the load cell body towards the end connected to the arm (more distal from the load cell body).
  • the maximum thickness is 0 60mm (proximal to load cell) and the minimum axial thickness is 0.50mm (distal to load cell).
  • the variable thickness embodiment with dimensions is shown in Figure 2B.
  • the serpentine spring comprises 8 linear members with progressive thicknesses of 0.6, 0.58, 0.55, 0.55, 0.52, 0.52, 0.5 and 0.5mm (decreasing from the linear member proximal to the load cell), the gap between adjacent members is fixed at 0.8mm, and the edge thickness is 1 02mm.
  • the total lateral thickness of the arm is 7.0mm.
  • Figure 2C shows a plot of the Stress 201 in this embodiment, with a maximum stress of 394.8MPa in the first U bend.
  • the gap is selected so that under full deflection adjacent linear members do not touch each other. Contact of adjacent linear members during deflection localises stress and reduces the factor of safety, and can lead to failure or reduced life. Ensuring no contact thus ensures a greater distribution of stress across the whole spring and a significant increase in the number of cycles.
  • Ti-6A1-4V has a yield strength is 827.4MPa and the S-N curve from multiple sources of literature shows that the material has nearly infinite life when the stress is less than 440MPa.
  • the Elastic modulus of the Ti-6Al-4Vsolution treated and aged is 104.8GPa. This corresponds to a max strain of 0.000367 (0.367%) and effectively allows for infinite life.
  • FEA results showed that all 3 serpentine spring designs remained below this level of strain, so we can confidently say that the life cycle of each serpentine spring should be much higher than 330,000 cycles (a target based on 3 years of heavy use). The fact that the design is predicted to have infinite life adds confidence that even when the serpentine spring is manufactured slightly out of tolerance or with defects, the spring can still function well enough to reach the 330,000-life cycle goal set for high-use apparatus.
  • the V4.0 waterjet was otherwise identical to the V3.9 wire EDM apparatus, however it outperformed the wire EDM in the testing. This suggested that the wire EDM was creating heat affected zones leading to reduced lifetimes. It was also noted that in the actual apparatus one side was a lot thinner due to the inability of the waterjet to precisely create parallel cuts in the titanium to the design specification. This suggested that if a design goal was a long life then a thinner spring would effectively reach the goal and have a better FOS as the spring would be more‘flimsy’ and bend easier, making it last longer. This lead to the version 4.1 designs tested, the properties of which are listed in Table 3 above. As shown in the above table the spring has effectively an infinite life, and would easily meet a nominal design target of 330,000 cycles.
  • each cover is configured with spring side portions 12 that extend axially beyond or over each serpentine spring 10 so that they at least partially covers each lateral side of the arm to prevent transverse movement of the arm as shown in Figure 4B. That is, the covers act as lateral guides for each spring arm to restrict movement within the plane of the apparatus (ie to and away from ramp 43) and prevent sideways or out of plane lateral movement.
  • FIG 4C shows a perspective view of the inside of a cover 3, showing the side portions 12.
  • the ends of the attachment portions 39, 27 are sloped to act as a stop to prevent the clip arm from over extending through the clip opening on return from a deflected position.
  • the side covers 3 need only at least partially extend over each spring hinge in order to prevent transverse movement of each arm.
  • each spring hinge may only cover a sufficient portion of the hinge to act as lateral stops or guides to prevent or resist unwanted lateral (out of plane) displacement of the arms. Extending over each spring hinge may mean that they may partially cover each lateral side of the arm (so as to prevent transverse movement of the arm).
  • the covers may be reinforced or formed with reinforcing elements to provide greater lateral resistance. In some embodiments the covers may cover some proportion of the hinge, such as over the first 50% of the serpentine portion (from the central body), or the first 75%.
  • the covers could be shaped as an extended projection which does not cover the full vertical extent of the serpentine spring or hinge (when viewed from the side) but could comprise a bar like extension along the vertical mid-line of the spring hinge. Again this could extend 50% along, 75% along or some other proportion of the spring hinge, or even past the hinge (provided it doesn’t limit access to the cavity).
  • the apparatus further comprises a switch 4, which in the embodiment shown in Figure 1 A and IB is formed in (or cut into) the load cell body 2.
  • Figure 5 A shows a close-up of the switch which is formed as a switch arm 13 with a switch boss 14 for actuating a push button or switch actuator 15 located in a switch cavity.
  • the arm 13 is formed with an arm thickness 61, above a channel with a channel length 63 and a constant gap width 62.
  • the arm 13 defines one side of the channel and extends over the switch cavity and includes switch boss 14.
  • the switch actuator 15 was an“E-Switch - Tactile switch 4.9X4.9mm 160G’ (Manufacturer No. TL3342F160QG) but other similar switches can be used.
  • a FEA analysis was performed to determine preferred switch dimensions and the results are listed in Table 6
  • FIG. 5B shows switch cavity dimensions according an embodiment based on switch E in Table 6.
  • Figure 5C shows a plot 501 of the Stress in this embodiment, with a maximum stress of 134MPa. Additionally the location of the switch was chosen to be near the U shaped cut-out, as this area maintained as much mechanical strength as possible of the titanium under axial loadings, but also was at a suitable non-influencing distance away from the U section for other design features such as PCB / cover / light pipes, etc.
  • the length 44 of the apparatus is 135mm long and the apparatus is 6mm wide and designed for use up to a maximum load of 100kg.
  • the load cell cavity has a transverse width 36 of 20mm and an axial length 37 of 16mm.
  • the width of the axial beams 35 is 5mm.
  • the load cell is located in the centre of the load cell body.
  • the serpentine spring 7 is an axial distance 38 of 13mm from the centreline of the load cell body, and the centreline of the recess is located an axial distance 34 of l5mm from the centreline of the load cell body.
  • the recess is formed of a rectangular section with a lateral depth 32 of 13.7mm and a radius of curvature 33 of 3.75mm.
  • the inner curve 31 of the clip 11 has a radius of curvature of 8mm and the outer curve 30 has a radius of curvature of l5mm.
  • the cut between the arm and hook is made at an angle 40 of 56.4° and has a gap width 41 of 0.4mm.
  • the angle of the ramp 43 that acts as a stop for the deflected arm has an angle of 31.1 °.
  • This apparatus has an isolated onset of strain in the centre of the middle cavity perpendicular to the force along its width.
  • This isolation of the strain 601 is shown in Figure 6A where the apparatus is under a 1000N force (around 100kg). With an axial loading of 1000N the maximum strain where the strain gauge will be installed is 0.00138. The strain in this area is proportional to the load, therefore when 100N is placed on the apparatus the maximum strain will then be 0.000138. At the smaller loadings the change in voltage will be less and thus the signal may need to be amplified. For this amount of strain and under this large loading of 1000N the apparatus displacement is not significant.
  • Figure 6B is a plot 602 of the displacement in the x direction and the maximum displacement in the x-direction is 0.347mm and is located at the U-section closest to the force. This is because the U-sections will concentrate the loading of the apparatus, as this is how it was designed to isolate the strain in the centre cavity. With smaller bi sections the strain in the centre cavity is offset from the centreline. To ensure accurate measurements the strain should be measured at the same point at each side of the centre cavity. This makes it easier to install the strain gauge in the centre, and for use in a full bridge Wheatstone circuit.
  • Figure 6C is a stress plot 603 of the apparatus under an axial loading of 1000N and the apparatus has a maximum stress of magnitude 208.7MPa located in the U-section closest to the switch cavity.
  • Figure 6C also shows that the bulk of the high stresses are in the thicker sections of the apparatus. This is designed as so to allow the apparatus to have heavier loads applied to it without experiencing plastic deformation as these parts of the apparatus have much more mechanical strength due to the more material being present in these locations.
  • the location of the boss apertures and other features (eg switch cavity) was selected to avoid areas of high stress.
  • these dimensions may be varied. Exact choice of dimensions will be dictated by the use scenario such as maximum load, extent of use (home vs clinic or gym), desired life time, etc.
  • the above device was designed for a life of at least three years and 330,000 cycles of the spring based on a heavy use case.
  • smaller designs with reduced maximum loads could be used in some settings.
  • the device could indicate whether the maximum load had been exceeded so the device can then be checked and recalibrated or replaced.
  • a thicker lOmm wide device for maximum loads up to l60kg could be used for a high use clinic, sporting club or gym use where additional strength may be required.
  • the load cell body requires accurate shapes to be cut and thus may be formed using waterjet cutting or Wire Electrical Discharge Machining (Wire EDM).
  • Waterjet cutting is faster than Wire EDM.
  • Wire EDM can also produce heat affected zones which can create fatigue zone.
  • Waterjet cutting has difficulty cutting small thicknesses.
  • For an apparatus around l35mm long and 6mm or 10mm wide Wire EDM is preferably used as it can provide flatter, smooth and more reliable tolerance standards allowing reliable and repeatable production of a compact apparatus.
  • wire EDM can create fatigue zones, a higher margin of safety can be used when designing features where the titanium is thin.
  • waterjet cutting may be feasible.
  • FIG. 7 is a schematic diagram of the electronics module 700.
  • the electronics module comprises a switch module 710, a status indicator module 720, a load cell module 730, a microprocessor module 740, a communications module 750, a power supply 760 and a wiring harness 770.
  • the power supply module 760 supplies power to the components of the circuit and may comprise a battery and voltage regulator to supply regulated voltages (eg 0V, +5V) to the other components).
  • the battery may be a rechargeable or non-rechargeable battery. In one embodiment the battery is a coin cell battery CR2032 which can be housed in the covers 3.
  • the microprocessor module 740 comprises a microprocessor or microcontroller including memory which stores the operating instructions, and analog and digital inputs and output lines.
  • the microprocessor module 740 processes switch inputs from switch module 710, initiates, processes and stores load cell measurements from load cell module 730, generates status indications via status indicator module 720 and coordinates transmission of load cell measurements via communications module 750.
  • the load cell module 730 comprises a Wheatstone Bridge circuit 23 formed from 2 pairs of strain gauge sensors (ie a full bridge circuit) located on one (transverse) surface 24 of the load cell.
  • a measuring circuit which may comprise an amplifier
  • the microprocessor board 740 directly by the microprocessor board 740.
  • a full bridge (four gauge) circuit is used, however in other embodiments a quarter bridge (single gauge on one of the transverse surfaces) or a half (two gauge) arrangement could be used.
  • the location of the strain gauges will typically be selected to maximise sensitivity to strain when a load is applied in a specific intended direction, such as an axial load via the clips (ie when in line with an elastic resistance band).
  • the micro strain gauge are a full Wheatstone bridge MicroMeasurement 50000hm strain gauge Model No. S5229A or S5020.
  • higher resistance strain gauges are possible up to 20,000 Ohms.
  • the load cell module may comprise amplifiers, filters, and other signal processing components to process or pre- processes the signals from the strain gauges and/or load cell. Alternatively processing of the signal (including amplification) maybe provided by the microprocessor module 740.
  • two Wheatstone Bridge circuits could be used located on opposing transverse surfaces 24 and 24'. Selection of the number of strain gauge sensors or Wheatstone Bridge circuits may be made based on sensitivity and reliability of the strain gauges. Typically the use of two Wheatstone Bridge circuits increases the cost, power and/or labour requirement compared to a single Wheatstone Bridge arrangement.
  • the switch module 710 may comprise a push button switch 15 or other switch arrangement which receives input via external switch actuator 4, and is connected to a microprocessor board 740 which interprets input signals.
  • the microprocessor module 740 may time the duration and/or frequency of switching input signals and toggle the state of the load cell apparatus. For example holding the button down for 5 seconds may toggle the apparatus on or off, holding the button down for 10 seconds may trigger a Bluetooth (or other wireless) pairing operation, and a single tap could wake up the apparatus to initiate measurements, and a double tap may trigger a readout of the battery life which is indicated by the status indicator 5.
  • the status indicator module 720 comprises one or more LEDs 48 which are controlled or driven by the microprocessor module 740 to provide visual feedback to the user about the status of the apparatus.
  • the light from the one or more LEDs 48 is directed to an externally visible status indicator 5, for example via a light pipe 18.
  • the status indicator 5 is configured to provide an indication of the level of force the load cell is measuring. For example in the context of measuring muscle weakness the indicator could indicate to the user that the load cell is approaching, reaching or exceeding the desired (target) force. This target force could be stored by the microprocessor, wirelessly transmitted to the apparatus (and stored by the microprocessor), or entered using the switch 4 (eg using a particular sequences of presses).
  • the status indicator can also be configured to indicate if the electronics of the load cell is on, or about to go to sleep, is transmitting data, has low power or is in a state of error. These states are determined by the microprocessor and can be indicated by specific colours and/or sequence of flashes.
  • the load cell apparatus is particularly suited to rehabilitation settings where users and clinicians are interest in muscle weakness (or more generally muscle strength) and rehabilitation or recovery progress.
  • a load cell it can be used for other suitable applications, for example as a digital scale where the measured load can be converted to a force and weight which can transmitted to and displayed on another device such as a smart phone, tablet or other computing apparatus.
  • Other variations are also possible. For example other clipping arrangements or attachment arrangements could be used.
  • a D shackle type arrangement could be used with a shaft that can be screwed in and out to allow attachment could also be used.
  • a keyed or combination padlock arrangement could be used.
  • FIG 8A is an exploded view of another embodiment of a portable load cell apparatus 1 comprising a removable spring arm 82.
  • the load cell body (as shown in Figure 8B) is formed of a single piece of material with spring arm receiving apertures 81.
  • the removable spring arm 82 comprises a shaped projection which is shaped with neck and a pair of overhang sections to allow the spring arm to be slotted into the spring arm receiving apertures 81 from a lateral direction, but prevented from being removed in a radial direction. Once slotted in place, the covers 3 prevent removal of the spring arm 82.
  • the joint is a dovetail joint in which the shaped projection has a tapered triangular shape 83 to interlock with a matching recess 81 , but in other embodiments other shapes could be used.
  • the removable spring arm further comprises an arm section 84 and a distal end 85 shaped to match the end of the attachment portion.
  • the shaped projection thus acts as spring hinge and the arm acts as a resilient beam in which the material properties of the beam allow it to be inwardly deflected, and the resiliency (elasticity) of the material will restore the beam towards the hook.
  • the load cell body is formed of a high accuracy extruded aluminium profile, cut to whatever thickness is required for loading conditions, and a separate Titanium removable spring arm 82.
  • FIG. 8C is a perspective view of another embodiment of a portable load cell apparatus comprising a spring arm 94 formed using a slot 91.
  • the slot 91 is formed of a straight section extending inwards from the lateral edge and parallel to transverse load cell surface 24 to form thin joining member 92, and then curves distally towards the end of the load cell 93.
  • Other variations using other configurations and materials are also possible, for example a titanium arm with a plastic carabiner body, an extruded aluminium body and hook, replaceable serpentine sprung gate, a replaceable spring, a replaceable arm, or a replaceable switch actuator arm.
  • FIGS 9 A and 9B show side and isometric views of another embodiment of a load cell apparatus 1 comprising a two part body housing formed of first load cell body component 111 and second load cell body component 112, and a sensor link member 113.
  • the sensor link member 113 supports the strain gauge(s) 23 and is formed as an I beam with first end 114 and second end 115.
  • Each of the load cell body components 111 and 112 comprise a recess (or cavity) with a shaped profile (for example a C shaped profile) within which the ends of the I beam are located - first end 114 in the recess 116 in the first load cell body component 111, and second end 115 in the opposing recess 117 in the second load cell body component 112.
  • the first load cell body component 111 and second load cell body component 112 are formed as an overlapping pair, each with attachment portion at one end, and a pair of arms at the other (internal) end of the component, and arranged so that when brought together one pair of arms overlaps the other pair of arms, and together they form a central cavity 21 within which the sensor link member 113 is located.
  • the two load cell body components 111, 112 slide axially within each other in order to carry bending and torsional stresses around the sensor link member 1 13.
  • the cavities 116 117 in each load cell body components 111, 112 are each filled with a shock absorbing material 121 122 such as urethane rubber or similar viscoelastic material shaped to fill the cavities 116 and 117 and encapsulate (or surround) the respective ends of I beam.
  • a shock absorbing material 121 122 such as urethane rubber or similar viscoelastic material shaped to fill the cavities 116 and 117 and encapsulate (or surround) the respective ends of I beam.
  • These ends of the I beams 114, 115 are each dimensioned so the lateral width (y dimension or height) are larger than the recess (cavity) openings 1 16 117 so the walls of the cavity overhang and act as a stop to prevent removal of the sensor link member when the sensor link member is moved axially.
  • the sensor link member 23 must be slid in place from a lateral direction (with respect to the load cell body), and once assembled the covers 3 hold the sensor link member in place (and prevent removal).
  • the shock absorbing members 121, 122 are dimensioned so they also overhang the I beams so that when the load cell is in tension (ie pulled at opposing end 8 and 1 1 ) the shock absorbing members are pinched or compressed between the overhanging walls of the recesses 116 117 and the I beam ends 114, 115 respectively. These minimise the bending stress in the link and provide mechanical compliance so the two load cell body components 111, 1 12 can slide some maximum distance (eg 1mm) before reaching the damage limit of the sensor.
  • the shock absorbing properties of shock absorbing members 121, 122 can be varied by suitable choice of the stiffness properties of the material.
  • the shock absorbing members 121 122 acts as a compliant member in series with the sensor link member 1 13 and also provided a pinned joint arrangement so that any bending moments and torsion are carried around the sensor link member 113 on other components. This is further achieved by ensuring that the internal ends of the second load cell body component 112 extend past the first end 114 of the sensor link member 1 13. This arrangement thus acts as a self-centring arrangement when the load cell is under tension to direct the strain through the sensor link member 113 on which the strain gauge(s) 23 are located, and eliminates cross talk effects (ie signals due to off-axis forces or bending moments). These shock absorbing members also act as over shock protection in the event the unit is dropped.
  • each of the load cell body components 111, 112 are formed with a pair of slots - (131, 132) and (135, 136), and the cover 3 comprises two pairs of projections (eg pegs) (133, 134) and (137, 138) that when the covers are fitted in place, project into the slots.
  • These act as overload protection by defining the maximum axial distance that the two load cell body components 111, 112 can slide (when under tension), and this is selected to be a distance less than distance at which the damage limit of the sensor is reached. Further, in the event of the sensor link member failing, these prevent the two load cell body components from completely separating, which could otherwise lead to the user being injured if rapid uncontrolled separation was not prevented.
  • This embodiment can also be cheaply and easily manufactured to suit high volume production and/or low load (eg lOOkg or less) or low usage scenarios such as home use by patients (as compared to high use sporting environments where more robust fully titanium model is more suitable).
  • high volume production and/or low load eg lOOkg or less
  • low usage scenarios such as home use by patients (as compared to high use sporting environments where more robust fully titanium model is more suitable).
  • the two load cell body components 111, 112 are formed as Aluminium or plastic extrusions which are cut in sections of the desired width (eg 6mm, lOmm) depending upon the required strength.
  • the two load cell body components 1 1 1 , 1 12 could be formed from plastic injection moulded parts, or 3D printed parts.
  • the attachment portions 101 102 can be formed as closed loops for permanent attachment situations, or they can be provided with serpentine clips as described herein, hooks or other removable attachment arrangements.
  • the load cell body components are formed to receive a removable titanium spring arm 82 as described above and shown in Figure 8B.
  • the two load cell body components 1 1 1 1 , 1 12 are formed as identical complimentary pieces, reducing the number of assembly parts.
  • the system shown in Figure 9 A can easily be assembled by sliding the first load cell body component 111 over the second load cell body component 112.
  • the shock absorbing members 121 and 122 can be fitted over the ends of the I beam sensor link member 1 13 and this is slid in place from a lateral direction, and then the covers 3, fitted with electronics and batteries are placed over the sides to lock the sensor link member 113 and two load cell body components 111, 112 in place.
  • the load cell apparatus could be fitted with an alarm module which detects the load approaching a threshold value and generates an alarm signal which may be provided to audio and/or visual interface to emit an alarm.
  • This may be an audio alarm (eg pitch and/or volume increasing as the threshold value is increased), a visual alarm (eg using visual indicators), and/or a haptic alarm (eg vibration frequency and intensity changes as load varies).
  • This embodiment could be used in towing or load carrying embodiments, for example where a 4WD or truck is towing or pulling an object using a cable with a predefined breaking strain. In this case the use of the load cell in series with the cable would allow the load cell apparatus to alert the driver (or others) that cable is approaching its load limit.
  • the wireless communications module could be omitted.
  • the joint 14 connects extended proximal 12 and distal 16 members and could be an elbow, wrist, knee or ankle joint.
  • the user 110 uses distal member 116 to use an extension apparatus 120 to perform an action.
  • the extension apparatus 120 is an exercise apparatus comprising a set of weights 122 operated by a handle 124 connected to the weights 122 via a cable 126 that passes around a pulley 128.
  • An embodiment of a portable load cell apparatus 1 is inserted between the weights 122 and the cable 126, although it could be placed between the handle 124 and cable 126 or in-line anywhere along the cable path provided it did not interfere with the pulley 128.
  • the load cell apparatus measures the force or load through the cable and wirelessly transmits this 131 to a computing apparatus 140.
  • the computing apparatus comprise at least one processor 142 and at least one memory 144, and a wireless communications interface 146.
  • the processor is configured to process the received force measurements from the load cell apparatus and display a force time curve 152 on a display 150, which may be integrated in the computing apparatus 140 or be external but operatively connected to the computing apparatus 140.
  • the computer apparatus may also include an audio interface for generating audio alarms or audio output, for example the audible pitch could change respectively with the changes in the force-time profile.
  • the computing apparatus 140 may also comprise haptic interface for generating haptic feedback, such as in response to an alarm signal or variation in the force-time profile.
  • the portable load cell may store force measurements, which are then transmitted to the computing apparatus for display at a later time.
  • the communications interface may be a wired interface such as over a USB cable or network cable, although preferably the communications interface is a wireless communications interface such as Bluetooth, BLE, WiFi, Zigbee, IrDA, etc.
  • the memory may be used to store instructions to establish a communications link with a portable load cell, and to process received data.
  • Processing of strain measurements into force measurements may be performed by the load cell, distributed between the load cell and the computing apparatus, or performed substantially by the computing apparatus, for example after basic filtering and amplification.
  • the computing apparatus may be a smartphone, a tablet, a laptop computer, desktop computer or other computing apparatus.
  • kits including a portable load cell apparatus and one or more extension apparatus (or devices).
  • Each extension apparatus is configured to receive one or more portable load cell apparatus, and comprise one or more movable surfaces such that in use movement of one or more movable surfaces generates a load on the portable load cell apparatus.
  • Figures 10B to 101 illustrate a range of extension apparatus
  • FIG 10B is a side view of a dynamometer extension apparatus according an embodiment.
  • the load cell apparatus 1 is connected between a pair of upper beams 162 and a pair of lower beams 163 which connect a left grip 164 and a right grip 165.
  • Each pair of beams 162, 163 comprises a first beam that pass through the clipping cavity, and a second beam external to the clip (and distal of the spring) to constrain the distal and proximal ends of each clip end 8, 11, and thus constrain the load cell apparatus 1.
  • each pair 162, 163 could be replaced with a single beam that passes through the clipping cavity.
  • the left grip 164 and right grip 165 form a pair of opposed grips.
  • the load cell may convert the strain measurements to a force measurement which is transmitted, or the raw strain measurements may be transmitted to the remote computing apparatus for processing and conversion to force measurements 140.
  • the extension apparatus may incorporate rigid or stiff materials to maximise the force transmitted to the portable load cell 1.
  • the extension apparatus illustrated in Figure 10B may be used to measure grip strength.
  • extension apparatus may be created to target different muscle groups or joints. In each case these extension apparatus are configured to take an action by the user, and convert/transduce the force into a direction that the load cell can measure.
  • Some extension apparatus may directly incorporate portable load cell apparatus 1 and some extension apparatus may incorporate dynamometers 160 incorporating portable load cell apparatus 1. This enables a wide range of movements to be assessed.
  • Figure 10C is a side view of an extension apparatus for groin adduction/abduction (ie to measure groin or leg strength) and incorporating the dynamometer extension apparatus of figure 10B according to an embodiment.
  • the left and right grips 164 and 165 (formed as curved plates) are connected by beams 171 172 to curved leg plates 172 174 respectively.
  • the distal sides of the leg plates 172 and 174 are padded and have an opposite curves to the grip they are connected to, and are designed to fit between the inner thighs of the user. The user can squeeze the two plates 172 174 towards each other, and the resulting strain (and force) is measured by load cell 1.
  • the beams 171 172 are fixed to the dynamometer.
  • the curved leg plates 172 and 174 are removable from the dynamometer.
  • the curved leg plates 172 and 174 are magnetically attachable leg plates.
  • Figures 10D and 10E illustrate an embodiment, in which Figure 10D is an top view of the inner side groin adduction/abduction plate 171 of Figure 10C, and Figure 10E is an top view of the grip 164 of dynamometer extension apparatus of Figure 10B and 10C.
  • the beams 171 and 172 are formed by two matching magnetic arrangements.
  • beam 171 is formed from joining leg plate magnet attachment arrangement 175 and grip magnet attachment arrangement 176.
  • the leg plate magnet attachment arrangement 175 comprises a beam with a circular cross section and comprising an even number of radially distributed magnets, in this case 4 magnets. Magnets alternate in their polarity, for example magnets 177 have a north pole and magnets 178 have a south pole.
  • a locating boss 179 is formed in the centre of the beam.
  • the grip 164 has a grip magnet attachment arrangement 176 with a complementary profile.
  • the grip magnet attachment arrangement 176 is also a beam with a circular cross section including 4 magnets (two north magnets 177 and two south magnets 178, with a locating recess 180 configured to receive locating boss 179.
  • the north magnets 178 of the leg plate magnet attachment arrangement 175 match the south magnets 177 of the grip magnet attachment arrangement 176, and the south magnets 177 of the leg plate magnet attachment arrangement 175 match the north magnets 178 of the grip magnet attachment arrangement 176.
  • the leg plates 172 174 can be removed though a simple 90° rotation (shown as arrow in Figure 10D), which will force opposing like magnets to align and thus allow the leg plate to be separated from the dynamometer.
  • the magnets are rare earth magnets. Adding further magnets would increase the number of angular orientations that the plates 172 174 can be located in with respect to the dynamometer 160.
  • the incorporation of a magnetic attachment mechanism on the grip surfaces of the dynamometer 160 allows it to be attached to a magnetic surface (eg steel bar) on one side, and a curved push (or pull) plate on the other (ie plate 174 in Figure 10C could be replaced with a wall or steel bar) to allow single limb testing to be performed.
  • Figures 10F and 10G show top and side views of a force plate extension apparatus 180 incorporating four dynamometer extension apparatus of Figure 10B according to an embodiment.
  • the force plate sensor 180 comprises an upper plate 181 and a lower plate 182 and four dynamometer 160 located in each corner.
  • the upper plate 181 and lower plate 182 are magnetically attached to the dynamometer 160 using the same magnetic attachment arrangement as used in Figures 10D and 10E.
  • the force plate extension apparatus 180 can be stood on, and the data from the four load cells used to assess stability. Alternatively the force plate extension apparatus 180 could be pushed with a hand.
  • Figures 1 OH and 101 show side and top views of a curved force plate extension apparatus incorporating triangulated dynamometer extension apparatus of Figure 10B according to an embodiment.
  • the top surface 184 is curved (ie ball like) which with the three dynamometer can be used to measure the direction of force applied to the surface.
  • FIG 10J is a perspective view of a tower-frame extension apparatus 190 and associated connection apparatus 194 196 incorporating load cell apparatus according to an embodiment.
  • the tower frame 190 comprises a curved beam 191 extending up from the base 193 which a series of loops 192 distributed along the beam 191.
  • a user can clip a load cell apparatus 1 to one of the loops 192 and clip the other end of the load cell apparatus to a connection apparatus, such as handle 194 or ankle cuff 196.
  • This extension apparatus can be used for a range of exercises or actions.
  • the beam has a curved profile (eg bracket like:“)”) in side view so that the upper most loop is above the head of the user when standing on the base.
  • the height of the beam is taller than most users, such as 2.5m.
  • the hooks are distributed along the beam at a range of heights, and load cell apparatus may be directly clipped onto them, or they could be clipped to a strap, cable or resilient band that is connected to a hook (or pass through multiple hooks).
  • the upper hooks can be used to measure a range of movements of upper limbs, whilst the lower loops can be used to measure a range of movements of the lower limbs.
  • the tower can also be used for simultaneous actions involving upper and lower limbs.
  • the handle comprises a fixed clip attachment projection, which comprises an aperture for receiving a clip of the load cell apparatus 1.
  • the handle 194 is a D handle formed as a rail with a set of apertures at designated angles (eg 0°, 45°, 90°) with a sliding clip attachment projection which a projection that can be inserted into the apertures to look the clip attachment at a designated angle with respect to the cross bar of the D.
  • the angle cuff 196 is shown closed. However it may include a hinge to allow it to be opened up and placed around the foot of the user.
  • a locking or fastening arrangement, such as pin, clip or Velcro fastener, or the hook of the load cell apparatus may be used to fasten the ankle cuff closed. When the use has ceased using, the load cell apparatus can be unclipped, and the cuff unlocked to allow the user to remove their foot.
  • door hinge anchor which is a plate that can be inserted through the small gap next to the hinge which is created when a door is open and sections of the anchor then“fold out” at an angle, creating a secure anchor point for straps, webbing and resistance bands to connect to for use when exercising.
  • the extension apparatus are preferably made from stiff materials/components to reduce force attenuation/dampening and maximise the force transmitted/applied to the load cell. For example rather than pulling an elastic band (eg theraband) a stiff polymer webbed strap is used.
  • the extension apparatus may have multiple load cells, and the multiple force-time profiles can be displayed.
  • the extension apparatus may also be configured to require the user to pull rather than squeeze.
  • the kit may also include a computer program product comprising instructions for causing a processor to connect to one or more portable load cell apparatus and display force-time profiles using received measurements.
  • the computer program is a downloadable smartphone app.
  • the kit may contain instructions on how to download the app, for example from an app store or website.
  • the portable load cell apparatus described herein combines multiple functions into a compact arrangement.
  • the load cell body can be constructed from a single piece of titanium and combine two attachment or connection features (spring carabiner clips), strain gauge/load cell geometry, two light pipes which also provide overload protection and a switch. Combining light indication and overload protection of a load cell into a single mechanism optimises space which is at a premium, allows users to view the load cell desired force from different positions, is aesthetically pleasing, follows good design principles of usability and part number reduction, protects the apparatus from damage and allows accurate measurement of force.
  • the shape of the hooks are designed to self-centre when attached to a band/handle, so the line of force will pass through the centre of the strain gauges, so as to maximise a strain measurement while minimising unwanted offsets in other directions.
  • the attachment mechanisms may use a spring hinge, in which the deflection of the spring is constrained to a defined range of movement, for example by the use of hook acting as a stop for the moveable arm, and a cover extending past the spring hinge to prevent lateral or transverse deflection.
  • a unique serpentine spring arrangement may be used as the spring hinge in which the width of the arms gradually changes, combined with a cover that acts as a lateral guide provides extremely long spring life (ie much longer than battery or intended apparatus life).
  • Embodiments of the load cell apparatus described herein can be put to a variety of applications.
  • Fully titanium robust models can be used in physiotherapist facilities, hospitals, sporting clubs, gyms, and similar clinical or high performance environments.
  • Lower cost/tolerance embodiments manufactured in part or full from other materials such as Aluminium and plastic may be used in homes by patients.
  • the load cell could be used more generally such as helicopter rescue or load suspension, or when pulling a load via cable (eg by a 4WD or truck).
  • the titanium clip and serpentine spring can provide robust performance, allowing easy attachment to a patient whilst providing confidence that the spring will not open unexpectedly (as the design to prevent the spring arm from moving laterally or over extending). Additionally the device can wireless transmit the actual load to a load master on the helicopter to ensure the load is within acceptable limits.
  • the load cell apparatus could also be used in structural applications to measure wind, water and other forms of environmental loadings on valuable infrastructure, such as aquaculture farms.
  • processing of signals may be performed directly in hardware, in a software module executed by a processor, or in a combination of the two.
  • processing may be implemented within one or more application specific integrated circuits (ASICs), digital signal processors (DSPs), digital signal processing devices (DSPDs), programmable logic devices (PLDs), field programmable gate arrays (FPGAs), processors, controllers, micro-controllers, microprocessors, other electronic units designed to perform the functions described herein, or a combination thereof.
  • ASICs application specific integrated circuits
  • DSPs digital signal processors
  • DSPDs digital signal processing devices
  • PLDs programmable logic devices
  • FPGAs field programmable gate arrays
  • processors controllers, micro-controllers, microprocessors, other electronic units designed to perform the functions described herein, or a combination thereof.
  • Software modules also known as computer programs, computer codes, or instructions, may contain a number a number of source code or object code segments or instructions, and may reside in any computer readable medium such as a RAM memory, flash memory, ROM memory, EPROM memory, registers, or any suitable form of computer readable medium.
  • processing may be implemented within one or more application specific integrated circuits (ASICs), digital signal processors (DSPs), digital signal processing devices (DSPDs), programmable logic devices (PLDs), field programmable gate arrays (FPGAs), processors, controllers, micro-controllers,
  • ASICs application specific integrated circuits
  • DSPs digital signal processors
  • DSPDs digital signal processing devices
  • PLDs programmable logic devices
  • FPGAs field programmable gate arrays
  • microprocessors other electronic units designed to perform the functions described herein, or a combination thereof.
  • Software modules also known as computer programs, computer codes, or instructions, may contain a number a number of source code or object code segments or instructions, and may reside in any computer readable medium such as a RAM memory, flash memory, ROM memory, EPROM memory, registers, hard disk, a removable disk, a CD-ROM, a DVD-ROM, a Blu-ray disc, or any other form of computer readable medium.
  • the computer-readable media may comprise non-transitory computer-readable media (e.g., tangible media).
  • computer-readable media may comprise transitory computer- readable media (e.g., a signal). Combinations of the above should also be included within the scope of computer-readable media.
  • the computer readable medium may be integral to the processor.
  • the processor and the computer readable medium may reside in an ASIC or related device.
  • the software codes may be stored in a memory unit and the processor may be configured to execute them.
  • the memory unit may be implemented within the processor or external to the processor, in which case it can be communicatively coupled to the processor via various means as is known in the art.
  • modules and/or other appropriate means for performing the methods and techniques described herein can be downloaded and/or otherwise obtained by a computing device.
  • a computing device can be coupled to a server to facilitate the transfer of means for performing the methods described herein.
  • various methods described herein can be provided via storage means (e.g., RAM, ROM, a physical storage medium such as a compact disc (CD) or floppy disk, etc.), such that a computing device can obtain the various methods upon coupling or providing the storage means to the device.
  • storage means e.g., RAM, ROM, a physical storage medium such as a compact disc (CD) or floppy disk, etc.
  • the invention may comprise a computer program product for performing the method or operations presented herein.
  • a computer program product may comprise a computer (or processor) readable medium having instructions stored (and/or encoded) thereon, the instructions being executable by one or more processors to perform the operations described herein.
  • the computer program product may include packaging material.
  • the computer program product may be an“App” available at an app store for download by a user.
  • the term“analysing” encompasses a wide variety of actions.
  • “analysing” may include calculating, computing, processing, deriving, investigating, looking up (e.g., looking up in a table, a database or another data structure), ascertaining and the like.
  • “analysing” may include receiving (e.g., receiving information), accessing (e.g., accessing data in a memory) and the like.
  • “analysing” may include resolving, selecting, choosing, establishing and the like.
  • the microprocessor module 740 is a microprocessor board that comprise one or more central processing units (CPU).
  • the CPU may comprise an Input/Output Interface, an Arithmetic and Logic Unit (ALU) and a Control Unit and Program Counter element.
  • the Input/Output Interface may comprise lines or inputs for receiving signals or data from the load cell module, switch module, indicator module and communications module.
  • the communications module is configured to communicate with an communications module in another device using a predefined communications protocol which may be wireless or wired (e.g. Bluetooth, Zigbee, IEEE 802.15, IEEE 802.11, TCP/IP, UDP, etc).
  • the microprocessor module may comprise a single CPU (core) or multiple CPU’s (multiple core), or multiple processors.
  • the memory is operatively coupled to the processor(s) and may comprise RAM and ROM components. The memory may be used to store the operating system and additional software modules or instructions.
  • the processor(s) may be configured to load and execute the software modules or instructions stored in the memory.
  • the computing apparatus 140 comprises at least one processor and at least one memory operatively connected to the at least one processor (or one of the processors) and may comprises additional devices or apparatus, and input and output devices/apparatus (the term apparatus and device will be used interchangeably).
  • the memory may comprise instructions to cause the processor to execute a method described herein.
  • the processor memory and display device may be included in a standard computing apparatus, such as smartphone, table computer, laptop, a desktop computer or in a customised apparatus or system (eg embedded or integrated computing apparatus).
  • the computing apparatus may be a unitary computing or programmable apparatus, or a distributed apparatus comprising several components operatively (or functionally) connected via wired or wireless connections.
  • the computing apparatus may comprise a central processing unit (CPU), comprising an Input/Output Interface , an Arithmetic and Logic Unit (ALU) and a Control Unit and Program Counter element which is in communication with input and output devices through an Input/Output Interface.
  • CPU central processing unit
  • ALU Arithmetic and Logic Unit
  • Control Unit and Program Counter element which is in communication with input and output devices through an Input/Output Interface.
  • the Input/Output Interface may also comprise a network interface and/or
  • the communications module for communicating with an equivalent communications module in another apparatus or device (eg a communications module 750 in load cell apparatus 1) using a predefined communications protocol (e.g. Bluetooth, Zigbee, IEEE 802.15, IEEE 802.1 1 , TCP/IP, UDP, etc.).
  • a graphical processing unit (GPU) may also be included.
  • the display apparatus 150 may comprise a flat screen display (e.g. LCD, LED, plasma, touch screen, etc.), a projector, CRT, etc.
  • the computing apparatus may comprise a single CPU (core) or multiple CPU’s (multiple core), or multiple processors.
  • the computing apparatus may use a parallel processor, a vector processor, or be a distributed computing apparatus including cloud based servers.
  • the memory is operatively coupled to the processor(s) and may comprise RAM and ROM components, and may be provided within or external to the apparatus.
  • the memory may be used to store the operating system and additional software modules or instructions.
  • the processor(s) may be configured to load and executed the software modules or instructions stored in the memory.
  • a phrase referring to“at least one of’ a list of items refers to any combination of those items, including single members.
  • “at least one of: a, b, or c” is intended to cover: a, b, c, a-b, a-c, b-c, and a-b-c.

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  • Physics & Mathematics (AREA)
  • General Physics & Mathematics (AREA)
  • Chemical & Material Sciences (AREA)
  • Analytical Chemistry (AREA)
  • Health & Medical Sciences (AREA)
  • General Health & Medical Sciences (AREA)
  • Physical Education & Sports Medicine (AREA)
  • Force Measurement Appropriate To Specific Purposes (AREA)

Abstract

L'invention concerne un appareil de cellule de charge portable qui comprend un corps de cellule de charge ayant une partie centrale, un couvercle, une cellule de charge située dans la partie centrale et un module électronique configuré pour obtenir une mesure de cellule de charge à partir de la cellule de charge et stocker ou transmettre sans fil la mesure de cellule de charge ou une mesure liée à la force sur la base de la mesure de cellule de charge. Le corps de cellule de charge comprend également des pinces à crochets au niveau de chaque extrémité, comprenant un crochet et un bras relié au corps par une charnière à ressort. Une extrémité du crochet agit comme une butée pour empêcher une déviation vers l'extérieur du bras, et le couvercle s'étend au-delà de la charnière à ressort pour empêcher un mouvement transversal. La charnière à ressort peut être un ressort en serpentin et peut être faite d'un alliage de titane. La cavité définie par le crochet et le bras peut avoir un profil conçu pour correspondre au profil du bras dévié, et peut avoir une forme de pointe de flèche arrondie pour former un crochet à centrage automatique pour assurer que la force se déplace axialement à travers la cellule de charge.
PCT/AU2019/000078 2018-06-22 2019-06-24 Cellule de charge portable WO2019241824A1 (fr)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
AU2018902252 2018-06-22
AU2018902252A AU2018902252A0 (en) 2018-06-22 Portable load cell

Publications (1)

Publication Number Publication Date
WO2019241824A1 true WO2019241824A1 (fr) 2019-12-26

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Cited By (5)

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Publication number Priority date Publication date Assignee Title
GB2600291A (en) * 2020-03-11 2022-04-27 Stanley Weller Keith A device for measuring a tension in a reciprocating chain
US20230112045A1 (en) * 2021-10-08 2023-04-13 Alton Shelton Tension Gauge Device
WO2023062426A3 (fr) * 2021-10-12 2023-07-20 Hygear Ltd. Systèmes d'entraînement par suspension à capacités d'apprentissage machine
WO2024073792A1 (fr) * 2022-10-05 2024-04-11 VALD Pty Ltd Dynamomètre multi-usages
GB2623802A (en) * 2022-10-27 2024-05-01 Remaker Ltd In-line exercise measurement device

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US20030024326A1 (en) * 2001-06-19 2003-02-06 Blakesley Patrick B. Seat belt tension sensor with overload protection
WO2008068391A1 (fr) * 2006-12-07 2008-06-12 Tractel S.A.S. Dynamometre electronique
WO2014125424A1 (fr) * 2013-02-15 2014-08-21 Žigon Andrej Dispositif de suivi d'entraînement par suspension
WO2018078197A1 (fr) * 2016-10-25 2018-05-03 Estel, S.L. Capteur de force de traction pour enregistrer et surveiller l'exercice physique

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Publication number Priority date Publication date Assignee Title
US20030024326A1 (en) * 2001-06-19 2003-02-06 Blakesley Patrick B. Seat belt tension sensor with overload protection
WO2008068391A1 (fr) * 2006-12-07 2008-06-12 Tractel S.A.S. Dynamometre electronique
WO2014125424A1 (fr) * 2013-02-15 2014-08-21 Žigon Andrej Dispositif de suivi d'entraînement par suspension
WO2018078197A1 (fr) * 2016-10-25 2018-05-03 Estel, S.L. Capteur de force de traction pour enregistrer et surveiller l'exercice physique

Cited By (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB2600291A (en) * 2020-03-11 2022-04-27 Stanley Weller Keith A device for measuring a tension in a reciprocating chain
GB2600291B (en) * 2020-03-11 2023-01-25 Stanley Weller Keith Method and apparatus for measuring rowing skill
US20230112045A1 (en) * 2021-10-08 2023-04-13 Alton Shelton Tension Gauge Device
WO2023062426A3 (fr) * 2021-10-12 2023-07-20 Hygear Ltd. Systèmes d'entraînement par suspension à capacités d'apprentissage machine
WO2024073792A1 (fr) * 2022-10-05 2024-04-11 VALD Pty Ltd Dynamomètre multi-usages
GB2623802A (en) * 2022-10-27 2024-05-01 Remaker Ltd In-line exercise measurement device
WO2024089540A1 (fr) * 2022-10-27 2024-05-02 Remaker Ltd Dispositif de mesure d'exercice en ligne

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