Patent Description:
Grip sensors are useful in a variety of applications. Some grip sensors have a variety of shortcomings. Among these shortcomings are a) the placement of exposed wires along the circumference of the grip; b) the requirement that the surface of the grip deform in order to register an event; c) the requirement for specific hand placement in order to register a grip, and/or detection of pressure applied to specific portions of the grip; and d) in many instances, the sensor element is sufficiently delicate that the choice of topcoats and the application of these topcoats is limited out of concern that the sensor element will be compromised during assembly. A need exists for an apparatus which overcomes these shortcomings.

<CIT> describes an interlock apparatus for fitness equipment comprising a microprocessor receiving grip signal inputs from grip sensors mounted on a load-bearing component of the fitness equipment. Signal conditioners provide noise filtering, signal debouncing and digital inputs for the microprocessor. Grips status monitors provide grip status signals used by microprocessor to determine the validity of the grip signals.

<CIT> describes a steering wheel for a motor vehicle having a sensor system with a capacitive sensor device, wherein the sensor system is designed to detect a presence of a human hand in a gripping area of the steering wheel and has at least one electrically conductive sensor structure which is arranged in a gripping area of the steering wheel and has a detection area, wherein the sensor system is designed in such a manner that the presence of a human hand in the detection area of the sensor device respectively causes, in comparison with a reference state, a capturable change in capacitive coupling of the sensor structure.

The dependent claims recite selected optional features.

Embodiments of the present invention provide robust capacitive grip sensors that may be used in a variety of applications, such as but not limited to barbell and dumbbell spotting apparatus. Apparatus as disclosed herein and efficiently measure the presence of a human grip without requiring deformation of a gripped surface area.

So that those having ordinary skill in the art will have a better understanding of how to make and use the disclosed systems and methods, reference is made to the accompanying figures wherein:.

The present invention now will be described more fully hereinafter with reference to the accompanying drawings, in which illustrative embodiments of the invention are shown. In the drawings, the relative sizes of regions or features may be exaggerated for clarity.

It will be understood that when an element is referred to as being "coupled" or "connected" to another element, it can be directly coupled or connected to the other element or intervening elements may also be present. In contrast, when an element is referred to as being "directly coupled" or "directly connected" to another element, there are no intervening elements present. As used herein the term "and/or" includes any and all combinations of one or more of the associated listed items.

In addition, spatially relative terms, such as "under", "below", "lower", "over", "upper" and the like, may be used herein for ease of description to describe one element or feature's relationship to another element(s) or feature(s) as illustrated in the figures. For example, if the device in the figures is inverted, elements described as "under" or "beneath" other elements or features would then be oriented "over" the other elements or features.

With reference to <FIG>, an exemplary apparatus <NUM> includes a substrate <NUM>, a grip sensor <NUM> and a processor hub <NUM>. As shown, the substrate <NUM> is a bar such as but not limited to a dumbbell bar. In embodiments in which the substrate is an electrically conductive material, such as a metal barbell bar, the grip sensor <NUM> includes a first electrically non-conductive layer <NUM> positioned on the substrate <NUM>, a plurality of strands of electrically conductive material <NUM> embedded in the first electrically non-conductive layer <NUM>, a second electrically non-conductive layer <NUM> positioned over the strands of electrically conductive material <NUM>, and a processor hub <NUM> operably coupled to the strands of electrically conductive material <NUM>. The strands of electrically conductive material <NUM> are oriented along the long axis of the substrate <NUM> and each strand is coupled to a processor <NUM> positioned on the processor hub <NUM>.

The substrate <NUM> may be any material typically used as a handle or grip for a device. The substrate <NUM> may be elongated. It will be apparent that the cross-section of the substrate <NUM> is not limited to a circular cross-section, as shown, but may have any suitable cross-section. The first and second electrically non-conductive layers <NUM> and <NUM> may be the same or different material. In one or more embodiments the first electrically non-conductive layer <NUM> and/or the second electrically non-conductive layer <NUM> are a ceramic material such as but not limited to a ceramic coating commercially available from Cerakote® of White City, OR. For example, Cerakote® H-<NUM> Electrical Barrier ceramic coating is a suitable material. The thickness of the first electrically non-conductive layer <NUM> may be from <NUM>-<NUM>. In one embodiment the thickness of the first electrically non-conductive layer <NUM> is <NUM>. The thickness of the second electrically non-conductive layer <NUM> may be from <NUM>-<NUM>. In one embodiment the thickness of the second electrically non-conductive layer <NUM> is <NUM>.

It will be apparent to those skilled in the art when the substrate <NUM> is an electrically non-conductive material, such as wood, non-conductive plastic, ceramic rubber, etc., a first electrically non-conductive layer may not be required. In such cases the grip sensor <NUM> may include, a plurality of strands of conductive material <NUM> embedded in, or laid upon, the substrate <NUM>, a non-conductive layer <NUM> positioned over the strands of conductive material <NUM>, and a processor hub <NUM> operably coupled to the strands of conductive material <NUM>. The grip sensor <NUM> may optionally include a first non-conductive layer <NUM>.

The second non-conductive layer <NUM> may be patterned and may include a knurled or roughened surface to facilitate grip. As shown in <FIG>, the second non-conductive layer <NUM> may be continuous, with no disruptions, about the plurality of strands of conductive material <NUM>. Alternatively, as shown in <FIG>, the second non-conductive layer <NUM> may be discontinuous, defining open cells <NUM>, exposing portions of the plurality of strands of conductive material <NUM>. The second non-conductive layer <NUM> may be applied in various manners to define the open cells <NUM>, e.g., applied as a mesh or lattice. Alternatively, the second non-conductive layer <NUM> may be applied continuously with subsequent removal of portions thereof to define the open cells <NUM>, e.g., by milling or etching. The open cells <NUM> may be regularly formed in shape and/or regularly spaced about the substrate <NUM>. For example, the open cells <NUM> may be circular or polygonal and spaced evenly to provide a honeycomb appearance.

The conductive material <NUM> is any suitable electrically conductive material such as but not limited to copper, silver, gold, aluminum etc. There may be any number of strands of electrically conductive material <NUM>. The thickness of each strand <NUM> may be any suitable thickness, such as, for example, from <NUM> gauge to <NUM> gauge (AWG). In one embodiment the thickness is <NUM> gauge. Each strand of electrically conductive material <NUM> is coupled to a processor <NUM>, positioned on the processor hub <NUM>, configured to detect capacitance in the respective strand of electrically conductive material <NUM> and compare against a predetermined threshold to determine an above or below state of capacitance, representable in binary output. Suitable processors include but are not limited to capacitive sensor processors available commercially from ISE Controls of Indianapolis, IN. The processors <NUM> are coupled to and powered by any suitable power source including but not limited to battery, house current, etc. The power source may be coupled to the processor hub <NUM> via conduit <NUM> or may be integrated in the processor hub <NUM>. Each of the processors <NUM> supplies binary output (ON or OFF) for each of the strands of conductive material <NUM> being monitored. The level of capacitance sensed in each strand of electrically conductive material <NUM> may be used to determine the binary output, e.g., a level of capacitance above a predetermined threshold may represent an ON state, with a level of capacitance below the predetermined threshold representing the OFF state, or the reverse may be utilized (OFF is above the threshold, ON is below). Any type of circuit allowing for binary output may be utilized, including any suitable logic circuit. The output of each strand <NUM> is separate and independent from all other strands. In one or more embodiments a host-side processor receives via conduit <NUM> separate and distinct channels of output (ON or OFF) from each of the processors <NUM>. For example, in a sensor with five strands (strands A-E) <NUM>, strands A-E each can signal ON or OFF. The host-side processor interprets the output and makes its own determination how to handle the data based on logic programmed in the host-side processor. It will be apparent to those skilled in the art the host-side processor can be programmed in any number of ways to process the output from the processors <NUM>. For example, and not by way of limitation, the five sensors may be assigned to variables L1, L2, L3, L4, L5 and provide signals as follows:.

<NUM> (palm of hand placed on the device).

At T2 (left hand fingers curl around the circumference of the device).

At T3 (the user lifts fingertips from the device but maintains a grip).

A host processor can process the signals to determine the presence and/or adequacy of a grip on the bar. For example, once variables L1-L5 signal ON, the host processor can signal equipment associated with the host processor to operate or not operate. The host processor may be programmed to signal equipment based on a lesser or greater number of ON signals, depending on the application. For example, the host processor may be programmed to determine an adequate grip exists based on the conditions at T3. The greater the number of electrically conductive strands and associated processors, the more sensitive the grip sensor.

The embodiment in <FIG> is suitable for any device requiring grip sensing of a single hand.

Now referring to <FIG>, in another embodiment a device <NUM> is designed to detect a two-handed grip. Each strand of electrically conductive material 30a is coupled to a processor <NUM> positioned on the processor hub 50a, and each strand of electrically conductive material 30b is coupled to a processor <NUM> positioned on the processor hub 50b. The host processor may process signals received from processor hubs 50a, 50b.

For example a single device may be outfitted with grip sensors as described so that it has <NUM> strands of conductive material (<NUM> on each side). Each of these is connected to its own processor <NUM>. The processor will output either ON or OFF (binary). There are numerous examples of devices that could employ a grip sensor as disclosed herein, including but not limited to handlebars of a vehicle such as a motorcycle, a steering wheel, controls for industrial machinery, etc..

The <NUM> sensors on the left may be assigned to variables L1, L2, L3, L4, L5; the <NUM> sensors on the right may be assigned to variables R1, R2, R3, R4, R5.

<NUM> (palm of left hand placed on the device).

<NUM> (palm of right hand placed on the device).

<NUM> (both left and right hand fingers curl around the circumference of the device).

Now referring to <FIG>, an exemplary method for forming a grip sensor is provided. The disclosed method is described in the context of a grip sensor for a single hand grip, but the same principles apply to a two-handed grip sensor. In this example the substrate <NUM> is a metal bar with a circular cross-section having a diameter of <NUM> inch. With reference to <FIG> and 4A, the bar is coated with Cerakote® ceramic coating. The thickness of this application is <NUM> millimeters. The benefits of using a ceramic are many. For example, ceramic is <NUM>) is non-conductive, <NUM>) cheaply and readily available, <NUM>) efficiently applied, <NUM>) easily etched, and <NUM>) extremely durable (IP69K) yet able to endure deflection without cracking.

With reference to <FIG>, the method involves etching into the ceramic coating <NUM> a plurality of channels <NUM>, such as five channels <NUM>, running lengthwise along the circumference of the metal bar <NUM>. The channels <NUM> are equally spaced and are <NUM> millimeter in depth and <NUM> millimeter in width. It will be apparent to those skilled in the art these channels need not be precisely equally spaced and the depth and width of the channels <NUM> may be varied.

Now referring to <FIG>, into each of the channels <NUM> is placed an uninsulated electrically conductive material <NUM>, such as but not limited to a bare strand of solid copper. It will be apparent to those skilled in the art the conductive material <NUM> may be deposited using any of the well-known methods available to the skilled artisan. For example, in accordance with the teachings of James B. D'Andrea, credited with being the founder of the field of hybrid microelectronics, conductive material may be etched into or otherwise formed in ceramic with the same efficacy as soldered wiring but at a fraction of the cost, with increased accuracy, and in a tiny footprint. The conductive material may be patterned on the non-conductive layer directly without forming a channel.

Now referring to <FIG>, the second non-conductive layer <NUM>, such as Cerakote®, is applied over the conductive material <NUM>. Like the first non-conductive layer, the second non-conductive layer <NUM> is preferably uniformly applied. This coating is <NUM> millimeters in the example. The total incremental thickness added to the metal bar is <NUM> millimeters or. <NUM> inches (total of. <NUM> inches to the circumference).

Claim 1:
A grip sensor (<NUM>) comprising:
a substrate (<NUM>);
an electrically non-conductive layer (<NUM>) disposed on the substrate (<NUM>);
a plurality of strands of electrically conductive material (<NUM>) spaced circumferentially about the substrate (<NUM>), wherein the plurality of strands of electrically conductive material (<NUM>) are generally parallel and are located between the electrically non-conductive layer (<NUM>) and the substrate (<NUM>); and,
a processor (<NUM>) coupled with the plurality of strands of electrically conductive material (<NUM>), the processor (<NUM>) being configured to detect capacitance in each of the respective strands of electrically conductive material (<NUM>) and compare the detected capacitance against a predetermined threshold to determine an above or below state of capacitance, representable in binary output,
wherein, a first subset of the plurality of strands of electrically conductive material (<NUM>) including a first strand (L1) and a second strand (L2) of the plurality of strands of electrically conductive material (<NUM>), the first and second strands (L1, L2) being in succession circumferentially about the substrate (<NUM>),
wherein, a second subset of the plurality of strands of electrically conductive material (<NUM>) including a third strand (L3), a fourth strand (L4), and a fifth strand (L5) of the plurality of strands of electrically conductive material (<NUM>), the third, fourth, and fifth strands (L3, L4, L5) being in succession circumferentially about the substrate (<NUM>),
characterised in that
contact by a user's hand simultaneously across the strands of the first subset (L1, L2) collectively generates an output representative of a palm of the user being in contact with the electrically non-conductive layer (<NUM>), and in that,
contact by the user's hand simultaneously across the strands of the second subset (L3, L4, L5) collectively generates an output representative of fingers of the user being in contact with the electrically non-conductive layer (<NUM>).