Parameter sensing system for an exercise device

A treadmill includes a frame, a deck assembly, at least one deck deflection sensor, and a control system. The deck assembly is supported by the frame. The deck assembly includes a longitudinally extending deck, at least first and second rollers, and a belt positioned about the deck and the first and second rollers. The deck deflection sensor is coupled to the deck. The deck deflection sensor is a contactless displacement sensor including an electrical intermediate device and an aerial. The control system is operably coupled to the at least one deck deflection sensor.

FIELD OF THE INVENTION

This invention relates to instrumentation and electronic control systems for fitness equipment. In particular, the invention relates to a parameter sensing system for exercise equipment. The parameters can include a user's presence and/or a user's position on an exercise device, and the speed and/or angle of inclination, of an exercise device.

BACKGROUND OF THE INVENTION

Many types of machines are used for fitness or sport training. Such machines are already known from their wide market availability for domestic, rehabilitation and commercial purposes. Treadmills, or running machines, are one of the most common forms of such machines. Treadmills typically include a support frame, a deck, an endless belt, a drive mechanism and a user interface. The endless belt typically extends over the deck and rotates around the deck and a pair of substantially parallel rollers to simulate the ground moving beneath a user as he or she walks or runs. The user interface associated with recently existing treadmills typically include a digital electronic control system with embedded software routines. Given the increasing functionality offered by digital electronics it is possible for the control system to store programs for different exercise routines, calorie-burning settings, timings, incline settings, speeds, etc. Users of such machines typically step on to the machine, enter their weight, choice of running program, desired speed or incline etc., and then begin to walk or run with the commencement of the belt's motion.

The belt motion typically ceases when the duration of the selected running program comes to an end, or when the user manually stops the belt by actuating one or more pushbuttons on the control panel. In other existing treadmills, a tether is used to releasably connect the user with the control system of the treadmill. The tether, typically a cord, string or cable, is often connected at a first end to the user and at a second end to the control panel of the treadmill. The length of the tether determines the distance the user can move away from the control panel. If the user moves away from the control panel beyond the predetermined distance, the second end of the tether disconnects from the control panel and the belt motion ceases.

Despite their widespread use, such existing treadmills have a number of drawbacks. Many users have difficulty entering their weight and starting the treadmill quickly. The digital electronic control systems with embedded software routines and increased functionality can sometimes be confusing, or even intimidating, for the user to properly use. Such confusion or intimidation caused by the machine's sophisticated user interface often effectively presents a barrier to widespread use, particularly by the elderly or technologically unsophisticated or those user's which may become embarrassed from their perceived ignorance in public fitness clubs or gymnasia.

For various reasons, such as those discussed above, it is often the case that the user does not enter his or her weight accurately. Consequently, the electronic control system is incapable of accurately calculating such useful information as calories burnt or intensity of training during a workout.

Also, particularly in busy fitness clubs and facilities, it is known that some users will step off the machine during their workout to get a drink, for example, but leave the machine's belt in motion. Whilst the first user is away from the machine it is possible for a second user to step on to the machine's moving belt without realising that the belt is moving. Such instances can also present a safety hazard. Although some existing devices incorporate the use of a tether in order to operate the machine, many find the use of tethers to be difficult to use, restricting, uncomfortable, and otherwise undesirable, and, as such, resist using the safety device. Other instrumentation, such as Linearly Variable Differential Transformers (“LVDTs”) or strain gauges, can be incorporated into a treadmill design in order to detect the presence of a user on the treadmill, or to measure the impact of the user's gate as they run or walk on a machine. However, such instrumentation is typically prohibitively expensive, complex, and impractical to deploy on most commercially available machines for mass market use.

Furthermore, many existing treadmills, particularly those configured for home use, fail to provide sufficient safeguards to prevent the undesired use of the machine by children. The inadvertent actuation of the endless belt by a small child can present a safety hazard.

Additionally, typically exercise machines, such as treadmills, require the user to manually enter or adjust controls on the control or display panel of the exercise machine using the user's hands in order to adjust the speed of the exercise machine, such as the speed of the belt on a treadmill. Such manual action of the user's hand(s) and arm(s) is ergonomically awkward and inconvenient for the user.

Also, the monitoring of the speed and incline of exercise machines, such as treadmills, can be difficult due to the repeated loading of the machine by the user and the vibration generated in response to the operation of the machine by a user. Many existing devices used to monitor speed and incline of exercise machines are expensive, and often exhibit poor durability and reliability.

Thus, there is a continuing need for an exercise machine, such as a treadmill, to automatically detect the presence of a user on the machine in a reliable, cost-efficient manner. It would be advantageous to provide an exercise machine, which can automatically measure the weight of the user without requiring the user to navigate and manually enter his or her weight into the control system of the machine. What is also needed is an exercise machine, which quickly and automatically shuts down when the user leaves the machine. There is also a continuing need for an exercise machine that can readily distinguish between a grown user and a small child and adjust its operation accordingly. A need exists for an exercise machine, such as a treadmill, to automatically vary the speed of the machine (such as the speed of the belt of the treadmill) based upon the speed of the user on the machine without requiring the user to manually input a change in speed using his or her hand(s). What is also needed is sensors which can be used to reliably, effectively and cost-efficiently monitor the speed and/or incline of exercise machines, such as treadmills.

SUMMARY OF THE INVENTION

According to a principal aspect of the invention, a treadmill includes a frame, a deck assembly, at least one deck deflection sensor, and a control system. The deck assembly is supported by the frame. The deck assembly includes a longitudinally extending deck, at least first and second rollers, and a belt positioned about the deck and the first and second rollers. The deck deflection sensor is coupled to the deck. The deck deflection sensor is a contactless or non-contact displacement sensor including an electrical intermediate device and an aerial. The control system is operably coupled to the at least one deck deflection sensors.

According to another preferred aspect of the invention, a treadmill includes a frame, a deck assembly, at least one deck deflection sensor, a drive assembly, and a control system. The deck assembly is supported by the frame. The deck assembly includes a longitudinally extending deck, at least first and second rollers, and a belt positioned about the deck and the first and second rollers. The deck deflection sensor is coupled to the deck. The deck deflection sensor is configured to produce a signal representative of a weight applied to the deck. The drive assembly is coupled to one or both of the first and second rollers. The control system is operably coupled to the drive assembly and the deck deflection sensor. The control system configured to prevent the treadmill from operating until the signal received from the at least one deck deflection sensor exceeds a predetermined magnitude.

According to another preferred aspect of the invention, a treadmill is configured to detect a user's weight. The treadmill includes a frame, a deck assembly, at least one deck deflection sensor, and a control system. The deck assembly is supported by the frame. The deck assembly includes a longitudinally extending deck, and a belt operably supported by the deck. The deck deflection sensor is coupled to the deck. The deck deflection sensor includes at least one transmit winding, at least one receive winding, and an electrical intermediate device. Wherein the application of the user's weight to the deck assembly causes displacement of the electrical intermediate device, which produces a change in mutual inductance between the transmit and receive windings. The control system is operably coupled to the at least one deck deflection sensor. The control system is configured to electrically measure and correlate the change in mutual inductance between the transmit and receive windings into a deck displacement measurement.

According to another preferred aspect of the invention, a treadmill is configured for operation by a user. The treadmill includes a frame, a deck assembly, at least one aerial, a control system, and first and second electrical intermediate devices. The deck assembly is supported by the frame and includes a longitudinally extending deck, at least first and second rollers, and a belt positioned about the deck and the first and second rollers. The aerial is positioned proximate the deck and includes a set of transmit and receive windings. The control system is operably coupled to the transmit and receive windings. The control system is configured to supply an alternating electrical signal to the transmit windings. The first and second electrical intermediate devices are secured to the right and left legs of the user, respectively. Each intermediate device is configured to produce a variation in the mutual inductance existing between the transmit and receive windings in response to a change in the relative position of the intermediate device to the windings.

According to another preferred aspect of the invention, a treadmill includes a frame, a deck assembly, a drive assembly, at least one aerial and a control system. The deck assembly is supported by the frame and includes a longitudinally extending deck, at least first and second rollers, and a belt positioned about the deck and the first and second rollers. The drive assembly is coupled to one of the first and second rollers. The drive assembly includes a plurality of components configured to rotate about a common axis during use. The aerial is coupled to the frame and positioned adjacent to at least one of the components of the drive assembly. The aerial includes a non-cylindrical arrangement of transmit and receive windings. The control system is operably coupled to the speed sensor. The at least one component of the drive assembly is configured to produce a variation in the mutual inductance of the transmit and receive windings during use as the components moves relative to the aerial. The variation in mutual induction produced by the relative movement of the component to the aerial correlates to the speed of the treadmill.

According to yet another preferred aspect of the invention, a treadmill includes a frame, a deck assembly, at least one aerial, a control system, and an electrical intermediate device. The deck assembly is supported by the frame and has a forward end. The deck assembly includes a longitudinally extending deck, at least first and second rollers, and a belt positioned about the deck and the first and second rollers. The aerial is positioned proximate the forward end of the deck assembly. The aerial includes a set of transmit and receive windings. The lift assembly is coupled to the frame and includes an incline actuator and an actuating arm. The actuating arm is coupled to the forward end of the deck assembly. The control system is operably connected to the lift assembly and to the transmit and receive windings. The control system is configured to supply an alternating electrical signal to the transmit windings. The electrical intermediate device is coupled to the forward end of the deck assembly. The intermediate device is configured to produce a variation in the mutual inductance existing between the transmit and receive windings in response to a change in the relative position of the intermediate device to the windings.

This invention will become more fully understood from the following detailed description, taken in conjunction with the accompanying drawings described herein below, and wherein like reference numerals refer to like parts.

DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS

Referring toFIGS. 1 and 2, an exercise machine, specifically a treadmill, is indicated generally at10. The present invention is also applicable to other types of exercise machines, such as, for example, an elliptical exercise machine, a stair stepper and a cycling machine. The treadmill10includes a frame12, operably supporting a deck assembly14, a drive assembly16, a lift assembly18and a control system20. The frame12preferably includes first and second longitudinally extending sides22and24, at least a pair of upwardly extending posts26interconnected at an upper end to a support plate28, which generally spans the width of the deck assembly14and supports the control system20, or a portion thereof. In a preferred embodiment, the frame12further includes a cross bar30upwardly extending from each side of the deck assembly14and extending across the deck assembly14adjacent the support plate28. The frame12is formed of a tough, rigid, durable material, preferably steel with a rust-resistant, multi-layered powder coating. Alternatively, the frame can be formed of other materials, such as, for example, other metals, composite materials, and combinations thereof. In alternative preferred embodiments, the frame12can be configured with or without one or more upwardly extending posts, and with or without one or more upwardly extending cross bars.

The deck assembly14includes a deck32, at least first and second substantially parallel rollers34and36and an endless belt38extending around the first and second rollers34and36and over the deck32. The deck32is a generally rectangular, longitudinally extending planar structure disposed between the first and second sides22and24of the frame12, and adjacent to the first and second rollers34and36. The deck32provides a running or walking surface beneath, and supporting, the portion of the belt38extending over the upper surface of the deck32. The deck32is formed of a durable, generally resilient material, preferably a high density fiberboard core laminated with a phenolic laminate. Alternatively, the deck can be formed of other materials, such as, for example, plywood, and other fiberboard compositions. The deck32is configured to deflect as the user moves and transfers his or her weight to different parts of the deck. For example, if the user is running and plants his or her left foot down at the top left corner of the deck, maximum deflection will occur there and to a lesser extent elsewhere.

The first and second rollers34and36extend between and rotatably couple to the first and second sides22and24of the frame12at front and rear portions of the frame12, respectively. The endless belt38longitudinally extends along the upper surface of the deck32around a portion of the first roller34, back through the frame12, and around a portion of the second roller36to form a closed endless loop. The width of the belt38is preferably generally equal to, or slightly less than, the width of the deck32. The belt38is formed of a resilient, durable material, preferably a multi-weave polyester. Alternatively, the belt can be formed of other materials, such as, for example, other elastomeric materials and other polymers. In an alternative preferred embodiment, the shape of the deck assembly, when viewed along a vertical longitudinal plane, is generally arcuate.

Referring toFIGS. 2 and 3, the deck assembly14further includes at least one deck deflection sensor40positioned adjacent to the lower surface of the deck32. In one preferred embodiment, the deck assembly14preferably includes six deck deflection sensors40positioned in spaced about locations adjacent to the lower surface of the deck32. In alternative preferred embodiments, other numbers of deck deflection sensors in spaced apart locations on, about, or beneath, the deck32can be used.

Referring toFIGS. 3 and 4, the deck deflection sensor40is a displacement sensor configured to measure deck deflection in a contactless or contact-free manner. The deck deflection sensor40is configured to measure the movement or deflection of the deck32caused by application of a user's foot during walking, running or standing on the treadmill10. The deflections resulting from walking or running on the treadmill10form a unique pattern according to the engineer's plate bending theory for a given amount of loading at a particular point.

In a preferred embodiment, the deck deflection sensor40includes an electrical intermediate device42and an aerial44. The intermediate device42is an indicating element or target, whose displacement alters the electrical inductance between the windings of the aerial44. Preferably, the intermediate device42includes a passive resonant circuit. In a particularly preferred embodiment, the intermediate device42comprises a resonant “LC” circuit including an inductance (L)46in the form of a coil of conductive tracks or wires, and a capacitor (C)48, in series. Most preferably, the coil of the inductance46is formed as a series of spiralled tracks on a printed circuit board50and the capacitor48soldered in series with the tracks. The intermediate device42is preferably removably connected to the lower surface of the deck32, and positioned adjacent to the aerial44, preferably within 0.1 to 100 mm of the aerial44. Alternatively, the intermediate device42can be fixedly secured to the deck, coupled to the deck, or placed directly adjacent to the deck. The sensor is substantially similar to the sensing apparatus described in UK Patent Application No. GB 2374424 filed on Jul. 31, 2002.

The natural frequency (fn) of the intermediate device42is calculable by the formula:

Preferably, the LC circuit of the intermediate device42has a natural resonant frequency in the range 100 kHz to 10 MHz for good levels of signal coupling without the requirement for expensive, high frequency electronics. Alternatively, the intermediate device42can be formed with other natural resonant frequency ranges.

In alternative preferred embodiments, the intermediate device can be a conductive metal target or ferrite slug. An LC resonant circuit is preferred however due to the resultant increased signal amplitude, signal quality factor and signal to noise ratio associated with the LC resonant circuit. In another alternative preferred embodiment, the previously described electrically passive intermediate device42can be an electrically active component powered by a power supply such as a battery. Such an electrically active embodiment is preferable if the distance between the intermediate device and the aerial exceeds 100 mm.

The aerial44is a sensing unit, which includes an arrangement of transmit windings52and receive windings54. In a preferred embodiment, the aerial44is has a generally planar shape. In alternative preferred embodiments, the aerial44can be formed in other shapes to suit the specific mechanical geometry of the it's location and, in particular, the location and motion of the intermediate device42, such as, for example, a cylindrical shape, a curved shape forming part of a cylinder, a hemi-spherical shape and an arcuate shape.

The transmit and receive windings52and54are preferably formed as tracks on a multi-layer printed circuit board56. Each aerial44preferably has a separate, single intermediate device42corresponding to it during operation. Alternatively, two or more intermediate devices42of substantially differing resonant frequencies can be used with a single aerial44. The aerials44are operably coupled to the control system20, and mechanically coupled to the frame12at locations adjacent to the intermediate device42. The aerials44can be connected to the frame12through mechanical fasteners, adhesives, or other conventional fastening means. The aerial44is preferably positioned within 0.1 to 100 mm from the intermediate device42. In other preferred embodiments the distance between the aerial44and the intermediate device42can be greater than 100 mm.

Referring toFIGS. 3 and 5, in a preferred embodiment the transmit windings52are energised with an alternating electrical signal supplied through the control system20, so as to produce a local alternating electromagnetic field58. In operation, deflection of the deck32causes the intermediate device42to move downward relative to the aerial44and within the limits of minimum and maximum deck deflection. The alternating magnetic field58is preferably at substantially the same frequency as the resonant frequency of the intermediate device42. As the deck32deflects, the intermediate device42moves along the alternating electromagnetic field causing the mutual inductance between the transmit windings52and receive winding54to vary in relation to the deck deflection. The accuracy of the signal produced by the receive windings54, and corresponding to the deck deflection, is generally not negatively affected by variations in the stand-off distance within the allowed range of 0.1 to 100 mm. The stand-off distance is the 0.1 to 100 mm distance separating the intermediate device42from the aerial44. Accordingly, referring toFIG. 3, as the intermediate device42moves relative to the aerial44in a direction, y, along the aerial44, variation in the stand-off distance, x, between 0.1 to 100 mm, does not negatively affect the deck deflection measurement taken along the direction, y. In an alternative preferred embodiment, the intermediate device can be coupled to the frame and the aerial can be coupled to the deck such that upon application of a load onto the deck, the aerial moves downward relative to the intermediate device.

FIG. 4illustrates the intermediate device42, as a resonant circuit, co-operating with an arrangement of the transmit and receive windings52and54. The transmit windings52are arranged as a first and second electrically separate generally sinusoidal and cosinusoidally or 90 degree phase shifted wound circuits52aand52bwhich are formed on two layers of the printed circuit board56over a pitch or wavelength L. Alternatively, the transmit windings can be configured in other phased intersecting arrangements. The printed circuit board56is conductively plated through holes to form the inter-layer electrical connections for each winding. In a particularly preferred embodiment, the printed circuit board56of the transmit and receive windings52and54and the printed circuit board50of the intermediate device42include photo-etched copper tracks or printed conductive tracks on an insulating substrate. Alternatively, simple windings of conductive wire or cable with an insulated cover are also feasible. However, printed circuit boards are preferable due to their ease and low cost of manufacture relative to high accuracy.

The receive windings54are formed as a simple loop extending along and around the transmit windings52. The shape of the loop formed by the receive windings54is preferably generally rectangular. Alternatively, the shape of the loop can be generally oval, circular, polygonal and irregular. It will be obvious to those skilled in the art that yet other arrangements are also feasible.

The intermediate device42is preferably positioned to be substantially parallel to, and within 0.1 to 100 mm of, the transmit and receive windings52and54of the aerial44. Alternatively, the intermediate device42may move normally to the transmit and receive windings52and54. In such arrangements an alternative sensing algorithm to that previously described is required. For example, an alternative algorithm would be to correlate the variation in received signal amplitude to relative displacement.

Referring toFIG. 4, the control system20is shown in greater detail. The control system20is operably coupled to the deck deflection sensors40, the drive assembly16(seeFIG. 2), and the incline assembly18(seeFIG. 2), and controls the operation of the drive and incline assemblies16and18. A power supply is electrically coupled to, and energizes, the control system20, the deck deflection sensors40, the drive assembly16and the incline assembly18. The control system20includes a frequency generator60, a set of receive electronics62, a micro-controller64, and a display panel66. The components of the control system20are preferably positioned at multiple locations about the frame12. In one preferred embodiment, the display panel66is positioned on the support plate28(seeFIG. 1) of the frame12, and the remaining components of the control system20can be positioned between the first and second sides of the frame12. Alternatively, the components of the control system20can be positioned at any location on or about the frame12. In one preferred embodiment, the control system20has a single micro-controller64(or microprocessor), a single frequency generator60, a single set of receive electronics62, and a single display panel66. If a single micro-controller or microprocessor is used, sufficient bandwidth must be available for the micro-controller or microprocessor to carry out frequent deck deflection measurements without interrupting the operation of other control system functions performed by the miccro-controller or microprocessor. In an alternative preferred embodiment, each deck deflection sensor40has its own dedicated micro-controller or microprocessor, or any combination of one or more frequency generators, sets of receive electronics, micro-controllers, and displays.

The frequency generator60provides an alternating electrical signal to the transmit windings52to produce the local alternating electromagnetic field58, which is substantially the same frequency as the resonant frequency of the intermediate device52. The alternating transmit signals energizing the transmit windings52are generated using an oscillating circuit source, preferably a 16 or 32 MHz crystal oscillating circuit source, reduced down to suit the resonant frequency of the intermediate device42, and fed in to the transmit windings52via the control system20. Power sources of other sizes and types can also be used. In particular, referring toFIGS. 4 and 5, the frequency generator60produces first and second phase shifted signals68and70to the first and second wound circuits52aand52bof the transmit windings52. The electric signals of the frequency generator60produce a mutual inductance between the transmit and receive windings52and54. As the intermediate device42moves relative to the aerial44, due to the deflection of the deck32, the mutual inductance between the transmit and receive windings52and54varies in relation to the amount of deck deflection.

The control system20, including the set of receive electronics62and the micro-controller64, is preferably also capable of comparing the combined received signals from the receive windings54, with the voltage and phase of the transmitted signals of the transmit windings52, such that the variation according to the actual position of the intermediate device42can be calculated against a preset or theoretical variation of mutual inductance. The set of receive electronics62includes a phase detector72and a position calculator74. The output of the set of receive electronics62, in particular the output of the position calculator74, is operably coupled to the microcontroller64and the display66.

The control system20is configured to process the signals of the deck deflection sensors40and to utilize the deck deflection information in a variety of useful ways. The deck deflection sensor(s)40can be used to automatically measure the weight of a user positioned on the deck of the treadmill. The automatic weight calculation eliminates the need for the user to manually enter his or her estimated weight into the control system20of the treadmill before commencing operation of the treadmill. The automatic calculation of user weight also eliminates the error associated with the user's estimate of his or her own weight. The user weight information can then be used for calculating information relating to the user's workout or for use in setting other machine parameters such as resistance level.

Additionally, the control system20can include a first predetermined deflection or weight setpoint. The control system20is then configured to prevent the treadmill10from operating unless the weight of the user meet or exceeds the first predetermined setpoint. The first predetermined setpoint can be a fixed value, or a value that can be adjusted as necessary. The first predetermined setpoint is configured to correlate to a minimum weight of a user. Accordingly, the first predetermined setpoint can be set at any predetermined weight value to accomplish the desired inadvertent start prevention feature. In one particularly preferred embodiment, the first predetermined setpoint corresponds to a user weight of 30 pounds. In alternative particularly preferred embodiments, the predetermined setpoint can be set to correspond to other weight settings, such as, for example, 40 pounds, 50 pounds, and 60 pounds. The first predetermined setpoint, therefore, prevents the inadvertent actuation of the machine by a small child, and virtually eliminates the risk of a small child climbing onto a treadmill deck and activating the treadmill.

Further, the control system20can include a second predetermined deflection or weight setpoint. The second predetermined setpoint is configured to cease or terminate operation of the treadmill if the weight of the user on the treadmill drops below the second predetermined setpoint for a first predetermined amount of time. The second predetermined setpoint can be set to correspond to a weight below that of a typical user. In one particularly preferred embodiment, the second predetermined setpoint corresponds to a user weight of 70 pounds. In alternative particularly preferred embodiments, the second predetermined setpoint can be set to correspond to other weight settings, such as, for example, 60 pounds, 50 pounds, and 40 pounds.

Alternatively, the second predetermined setpoint can be set as a percentage of the particular user's weight, such as, for example, 80 percent of the user's weight, 70 percent of the user's weight, etc. As an example, if the second predetermined setpoint is set at 70 percent of the user's weight, if a user weighing 200 pounds leaves an operating machine, if the weight on the deck32of the treadmill remains less than 140 pounds for the duration of first predetermined time period, the control system20will cease the operation of the treadmill10.

The first predetermined time period can be fixed or adjusted as necessary. In one particularly preferred embodiment, the first predetermined time period is five seconds. In other particularly preferred embodiments, other time periods can be used, such as, for example, 2 seconds, 3 seconds, and 10 seconds. This automatic shutdown feature will automatically shutdown the treadmill10, in the event the user falls from the treadmill, or leaves the treadmill without shutting the treadmill down. Thus, if the user leaves the treadmill10without shutting the treadmill down, the deflection sensors40will detect the reduction, or absence of, deck deflection (or user weight) and produce a corresponding signal to the control system20. If the signal corresponds to a weight that is less than the second predetermined value, and the signal remains for a period of time beyond the first predetermined time period, the control system will automatically shutdown the treadmill10, or simply stop the movement of the belt32of the treadmill10and place the controls in a standby mode.

When multiple deck deflection sensors40are employed on the deck32of the treadmill10, the control system20can be configured to differentiate between the deck deflection sensors40and to determine the impact pattern of the user's feet on the deck32. Such information can be used to adjust the speed or incline of the machine, or to warn the user that user is operating the treadmill at a location too close to either side edge of the belt of the treadmill. Such impact pattern information can also be used to perform stride length calculations and diagnostics.

FIG. 6shows a schematic of an example trace from 4 deck deflection sensors showing deflection (X) over time (t). The vertical offset of the various traces is shown for reasons of clarity. In this example the four sensors are arranged at four locations around or under the deck—front left, front right, rear left and rear right. Such an arrangement is only one of many possible arrangements, which may be deployed for maximum data with more sensors or maximum economy with fewer sensors. From the example arrangement it is possible to differentiate between impacts made by the user's left and right leg; left leg produces greater deflection on the front left sensor compared to smaller but concurrent deflection of the front right sensor and vice versa. Further, it is also possible to infer the user's lateral or longitudinal position by comparing impacts or deflections from each of the various sensors. Such longitudinal information is particularly valuable as it provides data to enable automatic motor speed control; speeding up as the user nears the front of the machine or slowing down as the user nears the back of the belt.

The number of impacts over a given time can be calculated and compared with the distance travelled by the belt and hence data on stride length or stride pattern compared to the speed and incline of the machine can usefully be generated for diagnosis of the user's performance.

The deck deflection sensors of the present invention enable deck deflection of the treadmill to be measured in an accurate, reliable, a relatively inexpensive and non-complex manner. The deck deflection sensors of the present invention are significantly less expensive than other commonly used instruments, such as, linear differential transformers, ultrasonic sensors, and optical sensors. Because the non-contact deflection sensors of the present invention are not negatively affected by variations in the stand-off distance within 0.1 to 100 mm, the tolerances of the components supporting the intermediate device and aerial of the deflection sensor do not have to be as tightly maintained as required by many existing conventional sensors.

Referring toFIGS. 6 and 7, in an alternative preferred embodiment, the position of a user on the treadmill10is sensed using at least one aerial144and at least one electrical intermediate device142. The aerial144is substantially the same as the aerial44. The aerial144is coupled to the deck32, preferably in a position that is substantially coplanar with the deck32. The aerial144also preferably extends over substantially the entire usable portion of the deck32. Referring toFIG. 7, in one particularly preferred embodiment, the aerial144is mounted to the lower surface of the deck32. In other embodiments, the aerial can be disposed within the deck or in a position adjacent to and substantially parallel with, the deck. In other alternative preferred embodiments, multiple aerials can be employed in a spaced apart arrangements about the deck. The aerial144, like the aerial44includes an arrangement of transmit and receive windings152and154, which are substantially similar to the windings52and54. The aerial144is operably coupled to the control system20.

The electrical intermediate device142is substantially the same as the intermediate device42. Referring toFIG. 6, in one particularly preferred embodiment, a separate electrical intermediate device142is coupled to each leg of the user. The intermediate device142can be attached to the user's shoe, ankle (such as through an ankle strap), lower leg, or knee (such as through a knee strap). Like the intermediate device42, the intermediate device142causes the mutual inductance between the transmit windings152and the receive windings154to vary in relation to the location of the intermediate device142on the deck32. The control system20monitors the mutual inductance from the windings152and154of the aerial144to identify the position of the user on the treadmill. Based upon these signals, or variations in the mutual inductance, the control system can determine the user's position, including fore and aft as well as right and left.

The control system20can be configured to emit audible warning signals to the user based upon the user's position. The audible signals can be generated directly from the control system20or from one or more speakers (not shown), or other sound generating device, mounted in the treadmill. For example, if the user drifts too far to the right of the treadmill during use, the treadmill10can emit a first audible warning signal to alert the user to change his or her position. Similarly, if the user drifts too far to the left of the treadmill during use, the treadmill10can emit a second audible warning signal. Likewise, if the user is too forward or rearward on the deck the treadmill can emit third and/or fourth audible warning signals to alert the user. The audible warning signals can be specific tones, or specific voice warnings. Such a configuration, would be of particular benefit to blind users who can rely on the audible warning signals to maintain proper position on the treadmill.

Further, in an alternative preferred configuration, the fore and aft positions of the user on the deck32can be used to adjust the speed the treadmill10. The control system20, which is coupled to the drive assembly16, can cause the speed to increase if the user is in a forward position on the deck, and decrease if the user is in a rearward position on the deck32. In yet another configuration, the user's position on the treadmill10can be used to automatically control the speed of the treadmill10. The control system20can be configured to increase the speed of the treadmill10, if the user takes a position toward the right side of the deck32, or decrease the speed, if the user takes a position toward the left side of the deck32during use. This right/left speed adjustment configuration may be more suited for shorter length treadmills.

The aerial144and intermediate devices142can also be used to enable the user to automatically adjust or control the incline of the deck32by varying the user's position on the treadmill10during use. Through its connection with the lift assembly18, the control system20can be configured to induce the lift assembly18raise the forward portion of the deck32, or increase the angle of incline of the deck32, if the user takes a forward position on the deck32. Conversely, the control system20cause the lift assembly18to automatically lower the incline of the deck32, if the user takes a rearward position on the deck32.

Unlike other existing technologies, such as sonic sensors or IR sensors, which are expensive, and often unreliable, the present invention using inductive position sensing, provides a reliable, cost effective means of automatically controlling or adjusting the operation of a treadmill. Further, the present invention doesn't require additional mounting of equipment onto handrails or displays of the treadmill.

Referring toFIG. 8, an another alternative embodiment of the present invention is illustrated. An aerial244is supported by the frame or other structure of the treadmill, and is positioned adjacent to a rotating component of the treadmill10, to function as a contactless speed sensor. The aerial244is substantially the same as the aerial44and includes an arrangement of transmit and receive windings, which are substantially the same as the windings52and54. In one preferred embodiment, the aerial244is positioned adjacent to the drive assembly16, which includes a motor80, an output shaft82, and a flywheel84. The motor80is electrically coupled to the control system20and to a power supply, and directly connected to the output shaft82. The output shaft82is coupled to the flywheel84and to one of the rollers34. The motor80causes the output shaft82, as well as the flywheel84and the roller34to rotate, thereby driving the belt38of the treadmill10.

In a preferred embodiment, the flywheel84includes at least one outwardly projecting constellation86, and preferably a plurality of constellations86. The flywheel84is positioned adjacent the aerial244such that the constellations86act as one or more electrical intermediate devices. The rotational movement of the constellations about the aerial244causes a variation in the mutual inductance of the transmit and receive windings252and254of the aerial244. The control system20monitors this variation of mutual inductance to determine the rotational speed of the flywheel84and the shaft82. In alternative preferred embodiments, the aerial can be positioned to other rotational members of the treadmill including the rotor of the motor, the output shaft, or one of the rollers. Further, the electrical intermediate device can be other conductive metal targets, a ferrite slug, a resonant LC circuit, or an electrically active component powered by a battery. The contactless configuration of this speed sensing aerial provides a low cost, reliably and accurate means of monitoring the speed of the treadmill without producing undesirable drag or resistance on the drive assembly.

Referring toFIG. 9, an another alternative embodiment of the present invention is illustrated. An aerial344is supported by the frame or other structure of the treadmill, and is positioned adjacent to a forward end90of the deck assembly14, to function as a contactless incline sensor. The aerial344is substantially the same as the aerial44and includes an arrangement of transmit and receive windings, which are substantially the same as the windings52and54. In one preferred embodiment, the aerial244is positioned adjacent to the lift assembly18, which includes a lift actuator92and an actuating arm94. The lift actuator92is electrically coupled to the control system20and to a power supply. The actuating arm94is coupled to the forward end90of the deck assembly14. In operation, the lift actuator92causes displacement of the actuating arm94which raises or lowers the height of the forward end90, thereby varying the incline, of the deck assembly14.

An electrical indicating device342is coupled to the forward end90. Like the intermediate device42, the intermediate device342causes the mutual inductance between the transmit and receive windings to vary in relation to the location of the intermediate device342relative to the frame12. The control system20monitors the mutual inductance from the windings of the aerial344to identify the position of the forward end90of the deck assembly14. Based upon these signals, or variations in the mutual inductance, the control system20can determine the incline of the deck assembly14.

The control system20can be configured with a single micro-controller64(or microprocessor), a single frequency generator60, a single set of receive electronics62for processing the signals or variation in inductance in the winding of one, two or all of the aerials44,144,244and344of the treadmill10. Alternatively, each aerial44,144,244or344, or group of 2 or more aerials, can have its own dedicated micro-controller or microprocessor, or any combination of one or more frequency generators, sets of receive electronics, micro-controllers, and displays.

While the preferred embodiments of the present invention have been described and illustrated, numerous departures therefrom can be contemplated by persons skilled in the art. For example, in an alternative preferred embodiment, the deck deflection sensor can be configured without an electrical intermediate device, and the transmit and receive windings can be positioned on two separate bodies. In this configuration separate electrical connections are required for each of the transmit and receive windings. Therefore, the present invention is not limited to the foregoing description but only by the scope and spirit of the appended claims.