CN211025003U - Exercise device and detachable force measuring device adapted to attach to resistance exercise device - Google Patents

Abstract

A home exercise device and a detachable force measurement device adapted to be attached to a resistance exercise device. The exercise device comprises: a resistance portion providing resistance to deformation caused by a force; and a strain measurement device configured to measure the force applied by a user to the exercise device.

Description

Exercise device and detachable force measuring device adapted to attach to resistance exercise device

technical field

The present invention relates to the field of exercise devices. In particular, the present invention relates to home exercise equipment and machines.

Background technique

Traditional resistance training exercise devices are mostly free weights made of iron. A person must lift weights in repetitive motions to build muscle and strength. However, irons for free weight machines are not portable and their use has to be limited to gyms for various practical reasons, they are not suitable for use in most homes, especially high-rise apartments with thin floors. Even if the weights don't wear down the floor concrete, the loud bump when a person lowers his weights after a series of repetitive motions can cause trouble, annoy and startle neighbors, disturbing their quiet enjoyment of their property.

To bring the gym "into the home," portable resistance training exercise devices have been designed to use lightweight elastic materials or elastic structures, such as rubber or springs, that deform when force is applied. These elastic materials or structures have a natural resistance to deformation. The user exerts the muscles against the resistance by deforming the device as if he were using a set of free weights. Advantageously, the lightness of the device makes the device easy to carry and relieves one from the occasional popping noise that may inadvertently be caused when using iron weights. However, while iron weights can be pre-weighed and marked to identify the amount of force a person must apply to lift the weight, it is not easy to measure the amount of force required to deform a piece of elastic material or elastic structure. The user must rely on the information provided by the manufacturer of the exercise device and believe that he is applying the amount of force required to deform the elastic material or elastic structure as claimed by the manufacturer. In practice, however, various deformable materials and structures wear and their tensile profiles change over time. Therefore, when this change occurs, the user may not actually be applying the force he thinks he is applying.

In today's world of health and appearance, while it is possible to perform resistance training at home using this lightweight, deformable material and structure, some people perform their training to a standard that is no less exacting than the highly precise standards of a professional gym. . For these people, it is important that they know exactly how much force they are applying during their resistance training exercise. This allows them to keep track of their training progress and also ensures that they are not underperforming, resulting in slow progress, or that they are not overperforming and risking injury.

However, these people are often dissatisfied. Often costs, time, and location make it difficult for these people to get to a gym with free weight equipment. However, home lightweight portable exercise devices do not provide the same accuracy in force requirements as free weight machines, and as noted above, it is often not practical to bring a set of free weight machines into the home.

Accordingly, the present invention proposes to provide an apparatus and method that allows a more accurate measurement of the magnitude of the force exerted by a user during exercise than the prior art allows, in order to help achieve better results in home fitness using portable home equipment Good training quality.

SUMMARY OF THE INVENTION

In a first aspect, the present invention proposes an exercise device comprising a resistance portion providing resistance to deformation caused by a force, and a piezoelectric element arranged to withstand a portion of the force part.

Resistance exercise devices that are not based on iron free weights tend to be inaccurate or unreliable with regard to the amount of force a user will need in an exercise. This is because the exact resistance of the exercise device cannot be confirmed by weighing with free weights. The present invention offers the possibility to solve this problem by allowing the user to measure the magnitude of the force he is applying by using a piezoelectric element, allowing the user to know precisely the force he has applied.

Preferably, the resistance portion is arranged in parallel with the piezoelectric element. This arrangement is suitable for a stretch-type exercise device and shares the load between the piezoelectric element and the resistance member of the exercise device. Sharing the load reduces the load on the piezoelectric element, allowing the piezoelectric element to last longer.

Alternatively, if the exercise device is a compression type device, it is preferred that the piezoelectric element is arranged in series with the resistance member of the exercise device, although parallel arrangement is not impossible.

Preferably, the piezoelectric element is removable from the exercise device and reattachable to any exercise device.

Preferably, the piezoelectric element is part of a piezoelectric assembly that includes an antenna for wireless communication with a remote computing device. This allows the piezoelectric element to be part of an IoT (Internet of Things) product, which allows the user to monitor his exercise over the Internet via his remote computing device. Examples of remote computing devices include smartphones.

Preferably, the piezoelectric element is part of a piezoelectric assembly comprising a display screen for displaying the force detected by the piezoelectric element. This allows the user to be able to read the force he is applying without looking at the remote computing device.

Preferably, the piezoelectric element is part of a piezoelectric assembly comprising a processor for converting the electrical charge of the piezoelectric element into force. This allows the piezoelectric assembly to calculate the force independent of the remote computing device, which is an advantage if the user does not have a remote computing device.

In a second aspect, the present invention proposes a detachable force measuring device adapted to be attached to a resistance exercise device, comprising a resilient member and a piezoelectric element connected to the resilient member, the resilient member having fasteners to connect the resistance exercise In the resistance portion of the device, the piezoelectric element has another fastener for securing to another portion of the resistance exercise device.

This allows any existing resistance exercise device to be retrofitted simply by attaching the detachable force measurement device to the existing resistance exercise device.

Preferably, the other fastener for securing to another part of the resistance exercise device includes an additional resistance portion.

Preferably, the piezoelectric element is part of a piezoelectric assembly that includes an antenna for wireless communication with a remote computing device.

Preferably, the piezoelectric element is part of a piezoelectric assembly comprising a display screen for displaying the force detected by the piezoelectric element.

In a third aspect, the present invention proposes a method of determining the amount of force applied to an exercise device, comprising the steps of: providing a piezoelectric element, securing the piezoelectric element to a moving part of the exercise device such that when the force is applied When on the exercise device, the piezoelectric element experiences at least some of the forces and exhibits an electrical charge, acquiring the charge as an indication of the magnitude of the force applied to the exercise device.

Preferably, the end portion includes fasteners for removably securing the end portion to the moving portion of the exercise device.

Preferably, the method further comprises the steps of applying a known force to the exercise device, measuring the charge exhibited by the piezoelectric device, and calibrating the charge of the piezoelectric device to the known force, wherein the calibration is available when the user uses the exercise device to interpret electrical output as force.

In yet another aspect, the present invention proposes an exercise device comprising a resistance portion providing resistance to deformation caused by force and a strain measuring device arranged to measure the amount of force exerted on the exercise device by a user. force.

The strain measurement device is capable of estimating the force exerted by the strain induced by the force on the resistance portion of the exercise device. That is, the resistance portion is elongated or shortened, and the strain measuring device monitors this elongation or shortening. Strain can be interpreted as the force exerted by the user of the exercise device by calibration.

Description of drawings

The invention will be further described with reference to the accompanying drawings showing possible arrangements of the invention, in which like numerals refer to like parts. Other arrangements of the invention are possible, and therefore the specificity of the drawings should not be construed as superseding the generality of the foregoing description of the invention.

Figure 1 is an illustration of one embodiment;

Figure 1a shows how a user uses the embodiment of Figure 1;

Figure 1b shows a Young's modulus curve indicating the deformability of the embodiment of Figure 1;

Figure 2 is a schematic diagram of components on a portion of the embodiment of Figure 1;

Figure 3 is a diagram of a second embodiment;

Figure 4 is a diagram of a third embodiment;

Figure 5 is a diagram of a fourth embodiment;

Figure 6 shows how the embodiment of Figure 5 may be applied to an exercise device;

FIG. 7 illustrates the application of the embodiment of FIG. 6 to an exercise device;

Figure 8 is an enlarged view of a portion of the embodiment of Figure 7;

FIG. 9 is another enlarged view of a portion of the embodiment of FIG. 7;

Fig. 9a shows that the embodiment of Fig. 7 is calibrated with a weight;

Figure 9b shows the embodiment of Figure 7 with a calibration weight provided as a kit;

Fig. 10 is a modification of the embodiment of Fig. 7;

Figure 11 shows how the embodiment of Figure 10 may be applied to an exercise device;

FIG. 12 shows the application of the embodiment of FIG. 10 to an exercise device;

Figure 13 shows a further variation of the embodiment of Figure 10 and the application of this variation in an exercise device;

FIG. 14 shows a resistance-based strain gauge that may be used in a variant of the embodiment of FIG. 1;

Figure 15 shows the strain gauge of Figure 14 applied to the embodiment of Figure 1; and

FIG. 16 shows the application of the strain gauge of FIG. 14 to the embodiment of FIG. 4 .

Detailed ways

FIG. 1 shows an embodiment 100 of the present invention, which is an exercise device 100 . The exercise device 100 includes a resistance portion 101 . The resistance portion 101 is an elongated member having two ends. Each end is equipped with a handle 103 . The two handles 103 will be held by the user's respective hands. In normal use of the exercise device 100, the user pulls the handle 103 apart, as shown by the arrows in the figure, and also as shown in Figure Ia. Typically, if the user stretches the handle 103 apart with their hands, the user exerts a stretching force on their deltoid muscles and squeezes their back muscles to train their back muscles. However, other muscle groups can be trained simply by using different limbs to hold the handles in different positions, such as the left leg pushing on one handle while the left hand pulls the other handle to train the trunk (not shown). The exercise device 100 may be used in different positions by a person, which is relevant to choosing which body part to exercise, which is not relevant for the purposes of this document.

The handle 103 in Figure 1a is drawn as a straight rod rather than a circular handle 103, but this does not deviate from the main point of the drawing.

Various types of materials can be used as the resistance portion 101 . For example, the resistance portion 101 is preferably a belt made of an elastomeric material, such as a rubber-based elastomeric material. In this case, the stiffness or tensile strength of the rubber determines the level of resistance, the amount of force required to pull and stretch the rubber. Alternatively, the resistance portion 101 is made of a non-deformable material, but has a deformable elastic mechanical design, such as a spring or the like, which would resist stretching if used in this embodiment.

The stiffness of an elastomeric material can be measured in terms of the linear component of Young's modulus, also known as the elastic modulus. The Young's modulus is shown in Fig. 1b. It is the mechanical property of a linear elastomeric solid material. It defines the relationship between stress (force per unit area) and strain (proportional deformation) in a material, and this relationship can be directly proportional until it reaches the breaking point. More specifically, Young's modulus represents the scaling factor in Hooke's law, which relates stress and strain. As the skilled person knows, Hooke's law is only valid when the elastomer and linear response is proportional to the applied force, and is not valid when the elastomeric material is stretched beyond the proportional region 111 into permanent deformation. The application of this scientific principle is well known to the skilled person and need not be described in detail herein.

Exercise device 100 includes piezoelectric assembly 105 . In this embodiment, the piezoelectric component 105 is arranged in the middle of the two resistance parts 101 . That is, the resistance portion 101 is provided as two parts, which are joined to opposite sides of the piezoelectric element 105 . Each side of the piezoelectric assembly 105 is attached to one end of the corresponding resistance part 101 , and the other end of each part of the resistance part 101 is connected to the corresponding handle 103 . Thus, pulling the handle 103 away will translate into the resistance portion 101 pulling on the piezoelectric assembly 105 .

Piezoelectricity, as known to the skilled artisan, is the charge that accumulates in piezoelectric materials (usually crystals, certain ceramics, and biological substances such as bone, DNA, and various proteins) in response to applied mechanical stress. The mechanical stress may be a pushing force, ie pressing on the piezoelectric material, or it may be a pulling force, as is the case in this embodiment. The charge exhibited in a piezoelectric material is proportional to the applied force. Therefore, the electric charge can be used to quantify the magnitude of the force applied to the piezoelectric material.

FIG. 2 is a schematic diagram of the piezoelectric assembly 105 . Preferably, the piezoelectric assembly 105 includes a housing 200 containing a piezoelectric element 201 , a voltmeter 203 , a microprocessor 205 , an antenna 207 and optionally a display 209 on the housing 200 .

Piezoelectric elements 201 are coupled on opposite sides thereof to the ends of the respective resistance portions 101 by physical couplings 211 or similar connectors, such that when the user pulls the handle 103 apart, the force stretches the piezoelectric element 201, causing compression. The electrical element 201 exhibits an electric charge. The charge is read by voltmeter 203 or any equivalent device that can be substituted for it. The voltage read by voltmeter 203 is provided to microprocessor 205 as information.

Skilled artisans will understand that by microprocessor 205 is meant a processor and all necessary components for its operation, including memory and the like. The memory of the microprocessor 205 contains calibration information to correlate the charge exhibited by the piezoelectric element 201 with the force applied by the user. After using the calibration to calculate the force applied by the user from the charge, the microprocessor 205 causes the display 209 to display a reading of the magnitude of the force. Therefore, by reading the display 209, the user can know the magnitude of the force he is applying.

The housing 200 is preferably provided with an antenna 207 so that a reading of the charge on the piezoelectric element 201 can also be transmitted to the remote computing device 107 and display 209 for processing. The remote computing device 107 is preferably a smartphone, but could also be a laptop or tablet. Such a smartphone 107 is shown in Figure 1a.

Optionally, the charge readings are converted into applied force readings, which are then sent to the remote computing device 107 . In this case, calibration is provided within the microprocessor 205 as described above. Alternatively, however, information about the charge of the piezoelectric element 201 is sent to the remote computing device 107, and the remote computing device 107 converts the charge reading into a reading of the applied force. In this alternative case, the remote computing device 107 contains the calibration information necessary to perform the conversion.

If the calibration information is contained within the microprocessor 205 attached to the exercise device 100, it will be difficult for an amateur hacker to reverse engineer the calibration, which is especially important if the algorithm is proprietary. In contrast, smartphones and computers are more vulnerable to hacking.

FIG. 3 shows another embodiment 300 . In this other embodiment 300 , in order to ensure that the coupling on the piezoelectric element 201 connected to the resistance portion 101 is not easily worn, the embodiment 300 includes a second resistance member 301 . In this way, the force exerted by the user is taken up by more than one resistance member 101 , 301 . This division of the burden onto each of the more than one resistance members 101 , 301 may extend the life of the piezoelectric assembly 105 . Furthermore, reducing the stress on the physical coupling also reduces the frequency with which the piezoelectric element 201 needs to be recalibrated. This provides greater robustness in embodiment 300.

In another embodiment 400 shown in Figure 4, the elongated member is not an elastomeric material. Alternatively, the elongated member is designed for compression. In this case, the embodiment 400 is suitable for training muscles such as the chest, such as by pressing the two handles 103 towards each other. One way of providing the possibility of compression is to use a hollow elongated member 401 into which another elongated member 403 is inserted. The end of the other elongated member 403 that is inserted into the hollow elongated member 401 is mounted with a compression spring 405 that resists compression. Thus, one end of compression spring 405 is attached to the end of another elongated member 403 , the other end of compression spring 405 is attached to piezoelectric assembly 105 , which in turn is secured to the deep end of hollow elongated member 401 .

Piezoelectric component 105 in this embodiment 400 also includes piezoelectric element 201 . The schematic diagram in FIG. 2 also applies to the piezoelectric assembly 105 in this embodiment 400 . Thus, the physical link 211 on one side of the piezoelectric element 201 is connected to the compression spring 405 . The physical link 211 on the other side is connected to the deep end of the hollow elongated member 401; the piezoelectric element 201 and the compression spring 405 are placed in series.

Therefore, pushing the other elongated member 403 into the hollow elongated member 401 requires compressing the compression spring 405 and pressing on the piezoelectric assembly 105 . This allows the piezoelectric element 201 in the piezoelectric assembly 105 to exhibit an electrical charge that can be read and correlated with a reading of the magnitude of the force the user applies when he pushes the two handles 103 towards each other.

In order for the piezoelectric element 201 in the piezoelectric assembly 105 to sense the compressive force, the compression spring 405 does not have to be provided. Any pressure applied to the piezoelectric element 201 will generate a charge in the piezoelectric element 201 . However, the compression spring 405 provides a certain range of motion that the user needs to flex his muscles for exercise.

As known to the skilled person, the mechanical structure of this embodiment 400 is such that some of the applied force compresses the compression spring 405 and some of this force is borne by the piezoelectric element 201 . How much the applied force is divided between the compression spring 405 and the piezoelectric element 201 depends on the design of the embodiment 400 . Since it belongs to the subject of known mechanics, it does not need to be detailed here, and the skilled person will be able to calculate it in an actual example product. Suffice it to say that the force applied to the piezoelectric element 201 generates an electric charge in the piezoelectric element 201 .

The charge is read by voltmeter 203 in piezoelectric assembly 105 and transferred to microprocessor 205 . The microprocessor 205 can convert the voltage into a reading of the force applied by the user based on a calibration formula that has been programmed into the microprocessor 205 . Alternatively, the charge is transmitted through the antenna 207 to a remote computing device 107, such as a smartphone or computer, which can apply calibration to convert the voltage into a reading of the force applied by the user.

FIG. 5 shows yet another embodiment 500 of the present invention, which is a detachable force measurement device 500 that can be attached to any stretch-based exercise device 601 to monitor a user on the stretch-based exercise device 601 applied force. This allows the detachable force measurement device 500 to be offered and sold separately so that the user can attach it to any stretch-based exercise device 601 to form a device similar to that of FIG. 3 . Thus, the detachable force measuring device 500 includes a piezoelectric assembly 105 similar to the previous embodiment, and has a housing 200 containing the piezoelectric element 201. Piezoelectric element 201 has a length of elastomeric material 501 attached on the opposite side. Each length of elastomeric material 501 has two ends, and one of the ends is attached to the respective side of the piezoelectric element 201, while the other end is provided with a clip or fastener 503 for attachment to a tension-based on the resistance part 101 of the stretching exercise device 601 .

FIG. 6 shows how the removable force measurement device 500 can be fastened or clipped to a suitable portion of the resistance portion 101 of the stretch-based exercise device 601 . FIG. 7 shows that the detachable force measuring device 500 has been clipped onto the stretch-based exercise device 601 . In Figure 7, the additional length of elastomeric material is drawn in a convex manner, but this is for illustration only and the skilled artisan will understand that the length of elastomeric material 501 will stretch as tightly as possible to The piezoelectric component 105 can immediately detect a slight stretch of the resistance portion 101 of the stretch-based exercise device 601 .

Figure 8 shows, in an enlarged view, a possible appearance of the piezoelectric assembly 105 in one embodiment. The housing 200 of the piezoelectric assembly 105 is shown in Figure 8, but the internal components are not shown. The housing 200 has two lugs that are secured to the two strips of elastomeric material 501 . The two bosses are actually physical couplings 211 shown schematically in FIG.

The connection to the two physical links 211 shown in Figure 8 is a flat strip, but a rubber strip with a rounded perimeter is the preferred choice. As long as the elastomeric material 501 that makes up the strip has a known Young's modulus, and the force distribution between the stretch-based exercise device 601 and the piezoelectric element 201 within the housing 200 is known, the The electrical charge exhibited by the electrical element 201 can then be correlated to the magnitude of the force exerted by the user on the stretch-based exercise device 601 . This is the basic mechanics that the skilled person will understand and does not need to be detailed in this article. Suffice it to say that a suitable calibration formula can be established for each product supporting embodiments of the present invention, and that it may depend on the resistance of the elastomeric material 501, the thickness of the elastomeric material 501, and the like.

Figure 9 is another enlarged view of the piezoelectric assembly 105, but without any strap attachments. The physical link 211 may be removably secured to the strip of elastomeric material 501 by a clip fastener, such as in a car seat belt (not shown). This means that the strips of elastomeric material 501 can be replaced if worn.

The piezoelectric assembly 105 of the detachable force measurement device 500 needs to be calibrated so that it can be used to measure the force applied to the stretch-based exercise device 601 . This is shown in Figure 9a. Calibration can be easily performed by first tautly attaching the detachable force measurement device 500 to the stretch-based exercise device 601 to form a piezoelectric assembly as shown in FIG. 7 . Subsequently, a weight 901 of known mass is placed suspended from one handle 103 of the stretch-based exercise device 601 while the stretch-based exercise device 601 is lifted by the other handle 103 .

When the weight 901 is held in the air by a handle 103, the piezoelectric element 201 in the detachable force measuring device 500 will experience the pulling force of the weight 901. Since the mass of this weight 901 is known, the charge exhibited by the piezoelectric element 201 in this case can be related to the mass. Therefore, charge can be scaled to mass.

It should be noted that, in addition to the mass of the weight 901, the mass of the stretching-based exercise device 601 itself may also generate some of the charges exhibited by the piezoelectric element 201, but it will be easy to design a suitable calibration formula so that it has no effect or can be easily adjusted. The design of the calibration formula is a matter of choosing an appropriate mathematical model to relate piezoelectric charge to force, and is specific to product design and does not need to be detailed in this article.

The calibration can be performed by software in the microprocessor 205 and the calibration results are stored in the memory of the microprocessor 205 . Alternatively, the piezoelectric element 201 charge reading may be sent to a remote computing device 107, such as a smartphone, for calibration, in which case subsequent readings of the piezoelectric element 201 charge would be converted by the remote computing device 107 success.

If a weight 901 of known mass is used for calibration, the accuracy will depend on the single point calibration formula. However, if two weights are used for calibration, the accuracy may depend on a two-point calibration, which may be more accurate. In this case, a first weight 901 of known mass is first suspended from one handle 103 while the detachable force measuring device 500 is held in mid-air to obtain a first calibration point, and then a second piece with a different The weight 901 of known mass is again held in mid-air to obtain a second calibration point. Again, the exact formula used may depend on the actual product based on the example and need not be detailed here.

As shown in Figure 9b, the weight and removable force measuring device 500 may be provided and sold as a kit.

FIG. 10 shows a detachable force measuring device 1000 , which is a modification of the embodiment of FIG. 7 , with a piezoelectric assembly 105 , but with only one resistance portion 101 attached to one side of the piezoelectric assembly 105 . The other side of the piezoelectric assembly 105 is provided with clips or fasteners to secure to the exercise device without a piece of intermediate elastic member. This is a more straightforward design, as the calibration formula only needs to account for the effect of varying modulus on one side of the piezoelectric component 105 rather than both sides.

FIG. 11 shows how the removable force measurement device 1000 can be fastened or clipped to a suitable portion of the resistance portion 101 of the stretch-based exercise device 601 . FIG. 12 shows a detachable force measurement device 1000 that has been clipped onto a stretch-based exercise device 601 . There is only one piece of elastomeric material 501 between the piezoelectric assembly 105 and the distal portion of the resistance portion 101 of the stretch-based exercise device 601 . Piezoelectric assembly 105 is directly secured to resistance portion 101 without the need for an intermediate piece of elastomeric material 501 .

FIG. 13 shows how the detachable force measurement device 500 can be clipped to other suitable portions of the resistance portion 101 of the stretch-based exercise device 601 . Piezoelectric device 1000 is attached directly to handle 103 of stretch-based exercise device 601 on one side and to another handle 103 via a piece of elastomeric material 501 on the other side. If the material of the handle 103 is hard plastic or metal, the material of the handle 103 may not deform, so the fixation to the handle 103 is stronger and the pulling force on the piezoelectric assembly 105 is more reliable to measure the applied force.

The fasteners or clips that the detachable force measurement device 500 may attach to the stretch-based exercise device 601 may be screws. In this case, holes need to be threaded into the handle 103 of the stretch-based exercise device 601 to secure the removable force measurement device 500. The clips or fasteners may be rod fasteners of the type shown in FIG. 14 that may join together the elastomeric material 501 of the removable force measurement device 500 and the resistance portion 101 of the stretch-based exercise device 601. There are many other means of securing the removable force measurement device 500 to the stretch-based exercise device 601, and their selection depends on the actual product design including embodiments of the present invention and need not be described in further detail herein.

Although the embodiments of Figures 7 and 10 are detachable force measurement devices suitable for a stretch-based exercise device 601, similar embodiments may be provided for compression-based exercise devices. For example, the piezoelectric assembly 105 may be purchased and sold separately, and the user himself only needs to secure between the compression spring 405 and the deep end of the hollow elongated member 401 .

Instead of piezoelectric elements, other types of strain sensors, strain transducers or strain gauges may be used, as they may be known and can be used to monitor the force applied by the user.

Strain gauges are typically passive transducers that convert mechanical stretch or displacement into resistance, inductance, or capacitance. For example, in embodiments using resistance-type strain gauges, power may have to be supplied to measure resistance changes. Thus, this is slightly different from a direct measurement of the force applied to the exercise device 100 through the electrical charge exhibited by the piezoelectric element. However, this difference lies in the circuit design, which the skilled person should be aware of and does not need to be detailed in this article.

An example 1401 of a resistance-based strain gauge is shown in FIG. 14, which is a flat substrate piece printed with curved conductive metal strips. Stretching the substrate in any direction, or compressing the substrate in any direction, as indicated by the large gray arrow, will cause a change in resistance. Resistance can be observed by measuring at endpoint 1403 of the strip. If the strain gauge is taped or adhered to the resistance member of the exercise device, as shown in Figure 15, stretching the resistance member will cause the strain gauge to stretch. In this manner, the extension of the stretch can be calibrated to calculate the amount of force applied to the exercise device.

Figure 16 shows the embodiment of Figure 4 modified to use a strain gauge 1401 in place of the piezoelectric assembly 105. When the spring 405 within an embodiment is compressed, the strain gauges that are stretched and adhered to several turns of the spring are allowed to relax, thereby changing the resistance measurable at the ends 1403 of the metal strips in the strain gauges 1401 .

Although preferred embodiments of the present invention have been described in the foregoing description, it will be understood by those skilled in the art that details of design, construction or operation may be made without departing from the scope of the invention as defined in the claims. Many changes or variants.

For example, other means of measuring applied force are contemplated and are within the contemplation of the present invention. An example is the use of an inductive coupling to detect spatial displacement and convert the displacement into a reading of the applied force. This is especially useful for compression-type exercise devices. Induction-based spatial displacement detection, such as LVDT (Linear Variable Differential Transformer), is well known and does not require any detailed description herein. Spatial displacement is not a direct measure of the applied force, but can be related by calibration.

Claims (11)

1. An exercise device, characterized in that it comprises: a resistance portion that provides resistance to deformation caused by the force; and A strain measuring device arranged to measure the force exerted on the exercise device by a user. 2. An exercise device, characterized in that it comprises: a resistance portion that provides resistance to deformation caused by the force; and A piezoelectric element arranged to withstand a portion of the force. 3. The exercise device of claim 2, wherein: The resistance portion is provided in parallel with the piezoelectric element. 4. The exercise device of claim 2 or 3, wherein: The piezoelectric element is removable from the exercise device. 5. The exercise device of claim 2 or 3, wherein: The piezoelectric element is part of a piezoelectric assembly that includes an antenna for wireless communication with a remote computing device. 6. The exercise device of claim 2 or 3, wherein: The piezoelectric element is part of a piezoelectric assembly that includes a display screen for displaying the force detected by the piezoelectric element. 7. The exercise device of claim 2 or 3, wherein: The piezoelectric element is part of a piezoelectric assembly that includes a processor for converting the electric charge of the piezoelectric element into force. 8. A detachable force measuring device adapted to be attached to a resistance exercise device, comprising: elastic member; a piezoelectric element connected to the elastic member; the elastic member has fasteners to connect the resistance portion of the resistance exercise device; The piezoelectric element has another fastener for securing to another portion of the resistance exercise device. 9. The detachable force measuring device adapted to be attached to a resistance exercise device according to claim 8, wherein, Another fastener for securing to another portion of the resistance exercise device includes an additional resistance portion. 10. A detachable force measuring device adapted to be attached to a resistance exercise device according to claim 8 or 9, wherein, The piezoelectric element is part of a piezoelectric assembly that includes an antenna for wireless communication with a remote computing device. 11. A detachable force measuring device adapted to be attached to a resistance exercise device according to claim 8 or 9, wherein, The piezoelectric element is part of a piezoelectric assembly that includes a display screen for displaying the force detected by the piezoelectric element.

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