Patent application title: Friction-Based Exercise Apparatus
Robert Amstler (Santa Monica, CA, US)
James Grimes (Yorba Linda, CA, US)
MAX EXERCISERS INC.
IPC8 Class: AA63B21012FI
Class name: Exercise devices user manipulated force resisting apparatus, component thereof, or accessory therefor utilizing frictional force resistance
Publication date: 2012-03-29
Patent application number: 20120077650
A friction-based exercise device is disclosed. Contemplated exercise
devices comprise a segmented shaft having one or more longitudinal
patterns running the length of the shafts or shaft segments. Cylindrical
sliders can be slid onto the shaft where an interior surface of the
slider comprises a complimentary pattern to and frictionally engages with
the longitudinal pattern of the shaft. When under a gripping force of a
user, the sliders flex inward toward the shaft and increases friction
resistance as the user slides the sliders along the shaft.
1. An exercise apparatus comprising: a shaft having a longitudinal
pattern running a length of the shaft; a cylindrical slider configured to
slide onto the shaft and having an interior surface comprising a
complementary pattern to the longitudinal pattern where the interior
surface frictionally engages the shaft under a griping force of an
2. The apparatus of claim 1, wherein the shaft is segmented
3. The apparatus of claim 2, wherein the shaft is hollow and further comprises a post-tensioning bar running the length of the shaft interior.
4. The apparatus of claim 3, where in the post-tensing bar is segmented.
5. The apparatus of claim 2, further comprising a segment joint configured to couple two shaft segments together.
6. The apparatus of claim 1, wherein the cylindrical slider comprises multiple longitudinal slats circumferentially disposed about an axis of the slider and defining the interior surface.
7. The apparatus of claim 6, further comprising three longitudinal slats disposed at approximately every 120 degrees about the axis of the slider.
8. The apparatus of claim 6, wherein the slats comprise a flexible material and are configured to flex toward the shaft in response to a user gripping the slider.
9. The apparatus of claim 6, wherein the slats are independently flexible.
10. The apparatus of claim 1, further comprising multiple cylindrical sliders.
11. The apparatus of claim 10, wherein at least two of the sliders have different base coefficients of friction with respect to the shaft when free of the griping force.
12. The apparatus of claim 1, wherein the slider resists rotation about its axis when disposed on the shaft due to the complementary patterned interior surface engaging with the longitudinal pattern of the shaft.
13. The apparatus of claim 1, further comprising an end cap configured to couple with an end of the shaft.
14. The apparatus of claim 13, further comprising an end plate configured to securely couple with at least one end of the shaft via the end cap.
15. The apparatus of claim 13, wherein the end cap is configured to tension a post-tension bar disposed within the shaft.
16. The apparatus of claim 1, wherein the longitudinal pattern comprises grooves.
17. The apparatus of claim 16, wherein the complementary pattern of the interior surface comprises rails configured to mate with the grooves.
18. The apparatus of claim 1, further comprising a wheel attachment.
19. The apparatus of claim 1, further comprising at least one weight configured to attach to an end of the shaft.
20. The apparatus of claim 1, further comprising at least one appendage attachment configured to couple with the cylindrical slider.
 This application claims the benefit of priority to U.S. provisional
application having Ser. No. 61/387,364 filed Sep. 28, 2010. This and all
other extrinsic materials discussed herein are incorporated by reference
in their entirety. Where a definition or use of a term in an incorporated
reference is inconsistent or contrary to the definition of that term
provided herein, the definition of that term provided herein applies and
the definition of that term in the reference does not apply.
FIELD OF THE INVENTION
 The field of the invention is fitness technologies.
 Fitness equipment takes on many different sizes, shapes, or functionalities targeting different regions of the body or targeting different types of users (e.g., men, women, children, etc.). Unfortunately, most devices can be quite dangerous to use because the device can exceed a user's safe-use threshold. For example, a user might unexpectedly exhaust their capabilities while exercising with free weights, thus putting the user at risk of injury due to loss of control over the weights. Better exercise devices would naturally operate under control of a user and well within the user's safety threshold at any given time during use, especially after long use when the user becomes most fatigued.
 One possible approach to designing a safe exercise device includes using user-controlled friction resistance components as opposed to mechanical springs, weights, bands, or other components that can easily put a user in danger. Such user controlled friction resistance components can provide resistance based on a user's grip. As the user fatigues, their grip also lessens, which in turn ensures the user remains within their safety limits.
 Example friction based equipment include the following references:
 U.S. Pat. No. 3,637,205 to Bankston titled "Hand Exercising and Frictional Resistant-Type Exercising Device", filed Jul. 9, 1970, describes a rod having a slideable sleeve, which a user grips.
 U.S. Pat. No. 3,971,255 to Varney et al. titled "Exercise Apparatus", filed Aug. 4, 1975, describes a device having hand grips having an adjustable braking means to create friction.
 U.S. Pat. No. 4,580,778 to Van Noord titled "Portable Exercising Apparatus with Force Gauge", filed Mar. 12, 1984, describes a power slide that has a friction mounting.
 U.S. patent application publication 2006/0276314 to Wilson et al. titled "Bar with Sliding Handgrips for Resistance Exercise Devices", filed Jun. 16, 2006, describes sliding handgrips for an exercise bar where the handgrips include rollers, which slide along the exercise bar.
 Interestingly, the above devices fail to place a user in full control of friction resistance while also providing a device that would also be completely portable.
 Unless the context dictates the contrary, all ranges set forth herein should be interpreted as being inclusive of their endpoints and open-ended ranges should be interpreted to include only commercially practical values. Similarly, all lists of values should be considered as inclusive of intermediate values unless the context indicates the contrary.
 Thus, there is still a need for exercise devices allowing a user to have real-time control over friction resistance.
SUMMARY OF THE INVENTION
 The inventive subject matter provides apparatus, systems and methods in which an exercise apparatus can have a rigid shaft, preferably a segmented shaft, on which one or more user-based friction resistance sliders can be positioned. In some embodiments, the sliders are cylindrical hollow sliders that slide onto the shaft so that the sliders can slide along the length of the shaft in an axial direction. The sliders preferably are configured to frictionally engage the shaft based on a gripping force from an individual. As the user fatigues, their grip will lessen thus ensuring the user has a reduced risk of injury.
 In some embodiments of the inventive subject matter, multiple shaft segments can be combined together to form a longer shaft. A shaft can have two, three, four, or more segments. Shaft segments can be held in position relative to one another via shaft joints and tensioned to retain rigidity via an internally disposed post tensioning bar. Shaft segments can also include longitudinal patterns, grooves for example, running the length of the shaft segments. When segments are combined, the shaft joints ensure the longitudinal patterns remain substantially continuous from one segment to another.
 Preferred sliders comprise multiple slats having on an internal surface a complementary pattern to that of the longitudinal pattern on the segmented shafts. For example, if the longitudinal pattern comprises grooves, the slider's internal complementary pattern could include rails. As a user grips the slider, the slats can flex radially toward the axis of the shaft under a gripping force of the user. The magnitude of the gripping force frictionally engages the patter of the slats with the pattern of the shaft giving rise to friction resistance as the user moves the sliders axially along the shaft.
 Various objects, features, aspects and advantages of the inventive subject matter will become more apparent from the following detailed description of preferred embodiments, along with the accompanying drawing figures in which like numerals represent like components.
BRIEF DESCRIPTION OF THE DRAWING
 FIG. 1 is a schematic overview of a segmented friction-based exercise device and its associated parts.
 FIG. 2 presents a two segment configuration of a contemplated exercise device.
 FIG. 3 presents a four segment configuration of a contemplated exercise device having an end plate and suitable for use in a standing position.
 FIG. 4 presents a more detailed overview of an end plate assembly.
 FIG. 5 presents different segment configurations a contemplated exercise device.
 FIG. 6 presents a configuration of the exercise device having appendage attachments.
 FIG. 7 presents a wheel attachment.
 FIG. 8 presents a more detailed overview of a wheel attachment having a wheel bearing.
 FIG. 9 presents an alternative slider assembly.
 As used herein, and unless the context dictates otherwise, the term "coupled to" is intended to include both direct coupling (in which two elements that are coupled to each other contact each other) and indirect coupling (in which at least one additional element is located between the two elements). Therefore, the terms "coupled to" and "coupled with" are used synonymously.
 The following discussion provides many example embodiments of the inventive subject matter. Although each embodiment represents a single combination of inventive elements, the inventive subject matter is considered to include all possible combinations of the disclosed elements. Thus if one embodiment comprises elements A, B, and C, and a second embodiment comprises elements B and D, then the inventive subject matter is also considered to include other remaining combinations of A, B, C, or D, even if not explicitly disclosed.
 As discussed previously, known exercise devices fail to provide continuous user-controlled friction resistance. What has yet to be appreciated is a friction-based exercise device can be constructed having hand grip sliders disposed on a segmented shaft where a user's grip controls friction resistance in a uniform manner around the grip. Such a device can be used for a full body workout.
 In a preferred embodiment, the shaft comprises a longitudinal patterned surface running the length of the shaft. An interior surface of a slider preferably has a complimentary patterned surface that frictionally engages the longitudinal pattern of the shaft. For example, the shaft can include grooves running the length of the shaft and the slider's interior surface can comprise one or more rails that frictionally engage within the grooves. Such mechanical engagements are considered advantageous to prevent rotation of the sliders during use. Other patterns are also contemplated including textured grooves or rails, spiral grooves or rails, tracks for bearings or wheels in the slider, or other types of patterns.
 The shaft can include one or more segments to allow a user to break the apparatus down into smaller components for easy portability or for different exercises. Longer shafts having two, three, four, or more segments can be used for standing exercises while shorter shafts having fewer segments can be used for upper body exercises. In some embodiments the shaft can be formed from extruded aluminum tubing where the extrusion process also forms grooves in the shaft.
 To prevent flexing of the shaft during use, the segments can be post-tensioned through a post-tensioning bar inserted axially within a hollow cavity of the shaft. The bar can be tensioned through one or more shaft end caps, possibly through mechanically coupling with the bar. Once tensioned, the shaft remains under pressure and remains rigid during use. The post-tensioning bar can be segmented as well.
 Segments of the shaft can be coupled via one or more segment joints that insert into a hollow cavity of the segments while also providing desired spacing between the segments. The joints can also have a lumen through which a post-tensioning bar can be threaded. Further, the shaft joints can be configured to provide continuity of the longitudinal pattern from one shaft segment to another. For example, the shaft joint could include a circular ridge is flush with the external surfaces of the shaft segments, including the pattern, so that the sliders can move freely from on segment, across the joint, to another segment without substantially catching on the interfacing edges of the segments.
 A roughly cylindrical slider can comprise multiple independently flexible slats disposed around an axis of the slider. Preferably each slat can flex radially inward toward the outer surface of the shaft independent of other slats in the slider. A preferred configuration comprises three slats positioned at roughly 120 degrees apart around the axis of the slider. Such spacing contributes to ensuring contact points of the slider's interior surfaces have equally distributed friction around the axis when griped, which would likely be unachievable in configurations having a greater number of slats. However, adjusting the number of slats in the slider is still considered to fall within the scope of the inventive subject matter. For example a slider could have two, four, five, or more internal slats. The slats in a single slider can typically be substantially identical to each other, while in other embodiments the slats in a slider could comprise different materials to adjust friction resistance as desired.
 Slats preferably comprise a material that would have a desirable coefficient of friction when engaged with the shaft, with or without a user's grip. Example materials can include Teflon®, nylon, or other materials. In view of the sliders frictionally engaging the shaft, the sliders eventually show wear. At which point the user can purchase replacement slats or sliders.
 In preferred embodiments, the exercise device includes at least two sliders, where two of the sliders could have different coefficients of friction without a user's grip. Providing sliders of different coefficients of friction allows users a greater range of exercises. For example, a high resistance slider can be gripped lightly to retain the sliders position, while a low resistance slider requires a tighter grip to exercise a target muscle group. It is also contemplated that a slider could include a friction brake to hold the slider in place, possibly in the form of a clamp, rubber gasket, screw, or other brake that would substantially hold the slider in place.
 Contemplated exercise apparatus can also include one or more additional components to broaden the range of available exercises. Example components can include a wheel that can be placed between two sliders on a shaft segment, a plate can be attached to an end of the shaft for vertical exercises where the plate is held stationary via the user's feet, spring loaded weights can be added to the end of a segment to create an oscillating dumbbell, or even appendage (e.g., leg, arms, etc) attachments that allow the sliders or shaft to couple securely with an appendage while the user grips the slider. For example, a leg harness or stirrup can be attached to a slider, which then can securely attach to a user's legs. The user grips the sliders to increase the frictional resistance of the sliders and then exercises their legs against the resistance.
 One should appreciate that a force or a pressure gauge is unnecessary because the exercise apparatus provides safe and instant friction resistance based a user's capability at a given point in time during the workout. One can consider the device as adapting instantaneously in a real-time fashion to the user throughout a workout. Gauges simply lack accuracy and eventually fail, which could cause the user to unknowingly enter a potentially risky situation. Still, it is contemplated that in some embodiments one can include pressure gauges, repetition counters, or other additional components as desired.
 A prototype of the above described apparatus was created based on a segmented aluminum shaft having two sliders comprising interior surfaces of nylon and Teflon. The device proved to be effective and weighed less than 1.7 Kg. The device proved to be quite robust even in view of the device being modular and having a low weight. When tensioned via a post-tension bar, the device became quite rigid capable of withstanding a high stress workout over an extended period of time and over many work outs, even when the device was configured with four segments.
 Preferred devices have segmented shafts of low weight and high stiffness (e.g., does not flex) where stiffness (S) can be expressed as a force divided by an amount of deflection (d) (e.g., S=F/d). The prototype flexes less than one millimeter (0.001 m) when under one Newton of force. The inventive subject matter is considered to include exercise apparatus having a modular or segmented shaft having stiffness-to-weight (S/W) ratio greater than 500 N/m Kg. Note that the prototype has an S/W ratio of (1N/(0.001 m×1.7 Kg)) 588 N/m Kg. Through the use of stronger, lighter materials (e.g., carbon fiber, etc.) contemplated segmented devices can have an S/W ratio greater than 1000 N/m Kg, or even greater than 2000 N/m Kg.
 FIG. 1 presents an overview of a modular, portable exercise apparatus 100. Apparatus 100 can include shaft 110 comprising one or more of segments 115 where the shaft has longitudinal pattern (e.g., groove) running the length of shaft 110. In the example shown, longitudinal pattern 116 comprises three sets of two closely spaced triangular shaped grooves where each set is disposed at about 120 degrees around the shaft. Apparatus 100 can also include one or more of cylindrical slider 120 that slide on to shaft 110 and are configured to glide along segments 115. Sliders 120 provide friction resistant under pressure or force exerted by a user's grip, which causes internal slats 123 to flex inward radially toward shaft 110. Sliders 120 can be configured to provide varying degrees of natural (e.g., un-gripped) friction resistance as desired. In a preferred embodiment one of slider 120 has a higher natural friction resistance than another slider 120. Note that slats 123 form an interior surface of sliders 120 where the interior surface adjacent to the exterior surface of shaft 110 has a complementary pattern 126 (e.g., rails) to the longitudinal pattern of shaft 110. In more preferred embodiments, slider 120 comprises three of slats 123 place at approximately 120 degrees around the axis of slider 120. The interior surface of sliders 120 frictionally engages shaft 110. Complementary pattern 126 preferably couples with longitudinal pattern 116 to prevent rotation of sliders 120 about the axis of shaft 110 during a workout. Additional embodiments of a slider can be found in reference to FIG. 9. Longitudinal pattern 116, as illustrated, can have a triangular cross section, while other embodiments can have other cross sectional shapes: square, semi-circular, rectangular, semi-elliptical, or other cross sectional shapes. Apparatus 100 can also include one or more of post-tensioning bar 130, which can also be segmented as shown. Bar 130 can be inserted into shaft 110 and can be tensioned to prevent shaft 110 from flexing. Segments 115 can be joined together via one or more of shaft joints 117. Sliders 120 are prevented from leaving shaft 110 by removable end caps 119.
 FIG. 2 presents one possible configuration of apparatus 100. The configuration shown comprises two segments 115 forming shaft 110. Post-tensioning bar 130 threads axially through shaft 110, shaft joint 117, and end plugs 118. End caps 119 couple with bar 130, preferably via a threaded mechanical coupler, and allow the user to tighten tension on bar 130, thus preventing shaft 110 from flexing during an exercise regimen.
 In the example shown, one of slider 120 has a higher coefficient of friction relative to the other slider 120. In some embodiments, the sliders are color coded to allow the user to determine which slider has a greater natural resistance. For example, a red slider could indicate a higher natural coefficient of friction while a green slider could indicate a relatively lower natural coefficient of friction.
 The configuration shown can be used for an upper body work out. For example, a user grips the high friction slider 120 holding it stationary relative to the shaft while the user also grips the other low friction slider 120. The user can then exercise upper body muscle groups by sliding the low friction slider 120 along the shaft under resistance created by their grip and due to the materials of the low friction slider 120. One should note all possible configurations or variations of use are contemplated.
 FIG. 3 presents another possible configuration of apparatus 100 comprising four segments 115 in a vertical arrangement. Apparatus 100 also include end plate 140 that couples to end plug 118 (not shown in FIG. 3) and is held in place by end cap 119 (also not shown in FIG. 3). An example standing exercise could include the user gripping upper slider 120 with both hands to create a resistance and standing on end plate 140 with their feet. The user can then bend at the waist using the slider's resistance as an opposing force to target a user's midsection muscles.
 FIG. 4 provides a more detailed view of how end plate 140 engages an end of apparatus 100. Post-tensioning bar 130 axially threads through segments 115, shaft joints 117, and through end plug 118. End plug 118 can comprise a patterned end that engages with end plate 140 to prevent rotation. End cap 119 can mechanically couple with bar 130 via a threaded connector, which allows the user to tight bar 130 to prevent flexing of segments 115 during use.
 FIG. 5 illustrates apparatus 100 can be arranged in numerous configurations including vertical configurations having two, three, four, or more of segments 115. A two segment configuration can be used in a sitting position by placing plate 140 under the user's lap. Furthermore, adjusting the number of segments 115 in apparatus 100 provides for sizing or dimensioning apparatus 100 to fit a particular user's size, to target specific muscle groups, or to target desired exercises.
 FIG. 6 presents a possible embodiment of apparatus 100 that includes one or more attachments 150 that can be used to increase the range of accessible muscle groups or range of exercises available to the user. In the example shown, the attachments include appendage attachment 150, thigh stirrups for example, that couple with sliders 120. A user can place their thighs within attachment 150 while gripping sliders 120. The user creates resistance by gripping sliders 120 and then moves their thighs toward each other and away from each other against the resistance crated by the user's grip.
 FIG. 7 presents another type of attachment, which can include abdominal wheel 153. Abdominal wheel 153 is configured to freely rotate about an axis of shaft 110 (not shown in FIG. 7) while sliders 120 are prevented from rotating as discussed above. A user can grip sliders 120 and place wheel 153 against a floor or other surface. The user can then perform various exercises targeting the abdominal region by rolling wheel 153 along the floor, possibly in a push-up like motion.
 FIG. 8 presents an exploded view of abdominal wheel 153. Of particular note, abdominal wheel 153 can include wheel bearing 155, which can also include complementary pattern 123. Thus, bearing 155 grips a shaft segment 115 while allowing wheel 153 to rotate freely around bearing 155.
 FIG. 9 presents an exploded view of another possible slider embodiment. Slider assembly 920, similar to slider assembly 120 presented in FIG. 1, also includes slats 923, slider caps 925, and grip 921. In addition, slider assembly 920 comprises fillers 924 that fit within grooves on the back side or externally facing side of slats 923. Fillers 924 aid in distributing gripping force across the longitudinal length of slats 923. Further, fillers 924 also create a flush outer surface for slats 923. When a person grips slider assembly 920, the person feels a substantially smooth gripping surface, increasing comfort to the user.
 Slider assembly 920 comprises additional features. When slider assembly 920 is fully assembled and placed on a shaft or a shaft segment, complimentary pattern 926 on slats 923 fully engage the shaft's longitudinal pattern's, with little or no radial gaps between the shaft external surface and internal surface of slats 923. Such an approach increases a friction resistance sensitivity of slider assembly 920 when under a person's grip. A small change in grip pressure can significantly alter friction of the slider assembly allowing a much greater range of applied friction while also reducing grip fatigue.
 It should be apparent to those skilled in the art that many more modifications besides those already described are possible without departing from the inventive concepts herein. The inventive subject matter, therefore, is not to be restricted except in the spirit of the appended claims. Moreover, in interpreting both the specification and the claims, all terms should be interpreted in the broadest possible manner consistent with the context. In particular, the terms "comprises" and "comprising" should be interpreted as referring to elements, components, or steps in a non-exclusive manner, indicating that the referenced elements, components, or steps may be present, or utilized, or combined with other elements, components, or steps that are not expressly referenced. Where the specification claims refers to at least one of something selected from the group consisting of A, B, C . . . and N, the text should be interpreted as requiring only one element from the group, not A plus N, or B plus N, etc.
Patent applications by James Grimes, Yorba Linda, CA US
Patent applications in class Utilizing frictional force resistance
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