Abstract:
An exercise device for lower body includes a housing defining two compartments, a tread positioned within each compartment, and compression spring assemblies positioned within each compartment. Each tread is supported by and floats on top of its compression spring assembly.

Description:
BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The present invention relates to exercise equipment. More particularly, exercise equipment of the type that a person can stand upon and work his or her lower body by engaging his or her feet with a pair of upwardly spring-biased treads. 
     2. Description of the Related Art 
     Exercise equipment is known that, to varying extents, satisfy important countervailing requirements. The most important requirements are (1) it must safely and effectively work at least one of the major muscle groups, isolated muscles, or the cardiovascular system, and (2) it must be fun and enjoyable. Exercise equipment that cannot satisfy these two basic requirements, while at the same time tertiary goals of being sturdy, reliable, convenient, inexpensive, and simple to use, will not be successful. For example, free weights achieve many of these goals, but without additional specialized equipment, they have limited application and can be dangerous if not used appropriately and/or without a spotter. Free weights are generally only useful in developing and exercising the upper body. 
     Lower body exercise has many medically important benefits including lower body weight, decreased risk of diseases such as diabetes, heart disease, and some cancers, lower body fat, improved physical appearance, reduced instances of depression, reduced symptoms of menopause, improved bladder control, reduced risk of injury, improved cholesterol levels, more positive self-esteem, better sleeping patterns, more energy &amp; stamina, and many others. It is not a matter of debate that lower body workouts exercising the largest muscles in the body, aerobically stressing the cardiovascular system, and testing balance and coordination contribute greatly to physical and mental well-being. 
     For cardiovascular, calorie-burning, and lower-body workouts, well known devices include the stationary bicycle, the treadmill, the ski-machine, the stair-climber (e.g., Reissued U.S. Pat. No. Re. 34,959, issued May 30, 1995 to Potts), the elliptical machine, and many other similar devices. These devices are effective, but are expensive and take up a great deal of floor space; they are not very convenient. Because some of these devices such as the treadmill and the stair-climber cannot provide a low-impact workout, they can exacerbate joint and spine problems, and be painful to those sensitive to high impact workouts. 
     Known devices include exercise trampolines, ones that are about 3 feet (1 meter) in diameter and sit 8 to 10 inches (20–25 cm) off the floor, are inexpensive and can provide a relatively good low-impact lower-body workout, but they are too soft and result in too much bounce and not enough resistance. Furthermore, they take up a large amount of floor space and can be difficult to store when not in use, e.g., they generally will not fit into a closet. 
     In recognition that there exists a need for a simple, compact, low-impact lower-body exercise device, a number of patents have issued disclosing devices attempting to fill this need. 
     For example, U.S. Pat. No. 4,279,415, issued Jul. 21, 1981 to Katz, discloses a treadle exercise device comprising a pair of hinged pedals (treadles) biased upwardly by a pair of springs and blown or cellular polyurethane foam. Like many spring-biased treadle devices, the hinge of the Katz device is located behind the foot. This causes the user to either stand on his or her toes when stepping down on the treadle which can excessively strain the ankle, or overstretch the ankle (Achilles) tendon. Similar devices include those disclosed in U.S. Pat. No. 3,814,420, issued Jun. 4, 1974 to Encke; U.S. Pat. No. 3,638,940, issued Feb. 1, 1972 to Mehaulic; U.S. Pat. No. 3,628,791, issued Dec. 21, 1971 to Garcia; and U.S. Pat. No. 3,295,847, issued Jan. 3, 1967 to Matt, Sr. 
     Another type of device, shown by U.S. Pat. No. 4,645,197, issued Feb. 24, 1987 to McFee, describes an exercise device having a biased platform hinged at a position in front of the foot. The platform is adjusted so that the springs provide just sufficient energy to maintain the user at about mid-position when quiescent. The springs are pre-stressed and provide nearly constant force through the full range of motion of the platform. A shock absorber connected to the platform dissipates energy. In use, the overall action of the body is described as “not unlike swimming doing the breast stroke with a porpoise kick” (McFee, col. 6, lines 57–59). This device takes up a great deal of floor space, is complicated to set up and use, and is not easy to store. 
     U.S. Pat. No. 6,132,338, issued Oct. 17, 2000 to Shifferaw and U.S. Pat. No. 4,200,282, issued Apr. 29, 1980 to Agyagos, and U.K. Patent Specification U.S. Pat. No. 1,348,531, published Mar. 20, 1974 for Wheeler each show variations on a “bounce board” which include a spring biased or flexible platform for exercise or fun. The U.S. patent to Shifferaw may mar the floor or damage carpeting due to movement of the feet when the board is flexed. A danger exists with the Shifferaw and Wheeler devices that they may jump or move during use. The Agyagos device&#39;s platform has a very restricted range of movement and is hinged at one end very close to the heel which requires user to therefore stand and jump on his or her toes. 
     U.S. Pat. No. 3,929,329, issued Dec. 30, 1975 to Rivera discloses spring supported ski-boot bindings for testing out the feel of a pair of ski boots. This device is not designed to exercise the individual and relies on the stiffness of the ski boots to prevent it from unwanted tilting and wobbling. It is not practical for daily workouts. 
     None of the above inventions and patents, taken either singly or in combination, is seen to describe the instant invention as claimed. Thus, an exercise device for lower body solving the aforementioned problems is desired. 
     SUMMARY OF THE INVENTION 
     The invention is an exercise device for the lower body, and includes a housing defining two compartments, a tread positioned within each compartment, and a compression spring assembly positioned within each compartment. Each tread is supported by and floats on top of its springs. 
     Accordingly, it is a principal object of the invention to provide an exercise device that provides a good workout, is simple and fun to use, and is compact, reliable, convenient, inexpensive, and sturdy. 
     It is another object of the invention to provide an exercise device that works the lower body and generates health benefits including one or more of: reduced body weight; decreased risk of diseases such as diabetes, heart disease, and some cancers; lower body fat; improved physical appearance; reduced instances of depression; reduced symptoms of menopause; improved bladder control; reduced risk of injury; improved cholesterol levels; more positive self-esteem; better sleeping patterns; and more energy &amp; stamina. 
     It is an object of the invention to provide improved elements and arrangements thereof for the purposes described which is inexpensive, dependable and fully effective in accomplishing its intended purposes. 
     These and other objects of the present invention will become readily apparent upon further review of the following specification and drawings. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is an environmental, perspective view of an exercise device for the lower body, in accordance with the present invention. 
         FIG. 2  is a sectional view taken along lines  2 — 2  of  FIG. 3 . 
         FIG. 3  is a sectional view taken along lines  3 — 3  of  FIG. 2 . 
     
    
    
     Similar reference characters denote corresponding features consistently throughout the attached drawings. 
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT 
     A lower body exercise device  10  according to the present invention is shown in  FIG. 1 . Lower body exercise device  10  includes a housing  12  and handle  14  extending up from a front end  15  of housing  12  to a position within easy reach of a person  16  standing on treads  25  of housing  12 . Housing  12  is supported by four feet  17 , two of which are seen in  FIG. 1 . 
     The structural details of exercise device  10  will now be discussed with reference to  FIGS. 2 and 3 , which are provided for illustrative purposes only and are not drawn to scale. Housing  12  includes a front panel  32 , a back panel  34 , a left panel  36 , a middle panel  38 , and a right panel  40  (collectively, “panels  32 – 40 ”), which collectively define two hollow compartments. Panels  32 – 40  are fixed to bottom panel  30 . In the case that panels  32 – 40  and bottom are made of wood, any known fasteners for attaching the panels as shown and described, including glue, dove-tail, screws, nails, biscuits, tongue-in-groove, etc., and combinations thereof, are contemplated. Other materials for construction are contemplated, including laminates, high-impact plastic, and other moldable or workable materials including metal. Any of panels  32 – 40  and bottom panel  30  can be produced as a single contiguous molded part without departing from the spirit and scope of the invention. 
     Housing  12  is made of three-quarter inch thick wood and stands, including feet, less than nine inches off the floor. Housing  12  is less than 20 inches long and about 17 inches wide. These dimensions are for illustrative purposes only; other dimensions and materials are of course contemplated. 
     Bottom panel  30  includes a plurality of raised cylindrical spring anchors  50 . Each spring anchor  50  may be embodied as a dowel screwed or otherwise attached to bottom panel  30 . Alternatively, if bottom panel  30  is made of molded material, spring anchors  50  may be formed integrally therewith. 
     Rather than raised cylindrical spring anchors  50 , they may be formed as recesses (not shown) formed in bottom panel  30 . For example, a blind hole having a diameter at least slightly smaller than the outside diameter of springs  52  for a force-fit may be drilled partway into bottom panel  30 . 
     A compression spring  52  is positioned on each anchor  50 . Each spring has an outside diameter of about 1.8 inches (4.6 cm) and a free length of about 6.0 inches (15 cm). 
     Springs  52  preferably are coated in an elastomeric material to reduce vibration noise. For example, springs  52  may be dipped in elastomeric material which is then allowed to cure. Suitable elastomeric material is available commercially from Plasti Dip International of Blaine, Minn. and sold under the trade name “PERFORMIX BRAND PLASTI DIP”. 
     A tread  60  is provided on a left side and a right side of center panel  38 . Each tread  60  is positioned for a respective foot of person  16  ( FIG. 1 ) using the device. Each tread bottom  62  includes a plurality of spring anchors  64  opposite spring anchors  50 . In the exemplary embodiment shown in  FIGS. 2–4 , tread  60  is formed from wood, though any suitable rigid material would suffice. As discussed above with respect to bottom panel  30 , spring anchors  64  may be formed as raised cylinders formed on tread bottom  62  or blind holes. In the exemplary embodiment, spring anchors  64  are provided by short cylindrical dowels fixed to tread bottom  62 . 
     Tread bottom  62  also includes stabilizers  66 . Stabilizers  66  are triangular or wedge-shaped pieces anchored to the tread bottom  62  using screws  67 , although other means of attaching stabilizers  66  to tread bottom  62  are of course contemplated. Stabilizers  66  and spring anchors  64  may be formed contiguously with tread  60  in the case where tread  60  is formed of moldable or workable material. 
     Sides  68  of stabilizers  66  slide along left and right side panels  36 ,  40 , and middle panel  38 , and help stabilize tread  60 . Stabilizers  66  therefore prevent lateral roll, or side-to-side tilting, of tread  60 . In addition, sides  68  are coated or covered with a low-friction material. In the case where wedges  66  and sides  36 ,  40  and middle panel  38  are wood, a suitable low-friction material is ordinary household wax. Other exemplary materials include PTFE (polytetrafluoroethylene) or acetal resin (such as that sold under the tradenames “TEFLON” and “DELRIN”, respectively, by DuPont of Wilmington, Del.). In addition or in place of a low-friction coating, a lubricant such as grease, wax or graphite may be used to reduce friction. Alternatively, rollers or other similar structure may be used to reduce friction between stabilizers  66  and side panels  36 ,  40  and middle panel  38 . 
     While the exemplary embodiment shows triangular-shaped stabilizers  66 , other shapes are of course contemplated. Quarter-circles, square blocks, an angle bracket, or simply a pair of beams extending entirely across tread bottom  62  are all contemplated. The number of stabilizers  66  may also be varied provided that at least one side  68  is on each side of tread  60  to prevent lateral roll with respect to housing  12 . 
     To reduce friction and noise generated by relative movement of tread  60  along the front and back panels  32 ,  34 , rollers  80  are provided at each corner of tread  60 . Each roller  80  is positioned over a pin or dowel  82 . Rollers  80  are preferably made of metal or some low-friction resin material. A wear surface  84  is attached at either side of each tread  60  to front panel  32  and back panel  34  so that each wear surface  84  is positioned for contact with a corresponding roller  80 . Wear surfaces  84  may be formed of metal or plastic, and are attached by screws  86  or other means as would occur to the ordinary practitioner. Wear surfaces  84  are helpful in protecting front and back panels  32 ,  34 , particularly when they are made of wood, as in the exemplary embodiment shown, or other material susceptible to wear. For other materials, wear surfaces  84  may be integral to the front and back panels  32 ,  34 . 
     Each tread  60  may include a friction pad  70  to improve the friction between tread  60  and a user&#39;s foot. Friction pad  70  may comprise a textured rubber mat of the type used in treadmills. Other known means for enhancing friction of treads  60  are contemplated. For example, friction enhancers could include a textured surface of each tread  60 . 
     Stops  90  prevent treads  60  from popping out of housing  12 . In the exemplary embodiment, stops  90  are made of half-inch (1.3 cm) wood and are attached to front, side and middle panels of housing  12  at the top corners of each compartment. Each stop  90  includes an elastomeric stop  94  positioned in groove  92  formed in the bottom of the stop. Each elastomeric stop  94  engages a corresponding roller  80  at the same time friction pad  70  engages stops  90 . Elastomeric stops  94  reduce noise generated when a tread  60  travels up and engages stops  90 . 
     Springs  52  are compressed only about one quarter inch (0.6 cm) from free length when tread  60  engages stops  90 . Springs  52  are quite stiff and provide a strong return force when deflected. In the exemplary embodiment, spring rate of each tread  60  is about 156 pounds per inch (273 N/cm) of deflection. Thus, a 156 pound person, when placing all his or her weight on one tread  60  will sink only about 1 inch. In the exemplary embodiment of  FIGS. 2 and 3 , each tread  60  is supported by eight springs. To obtain the spring rate noted above, four springs with a spring rate of 15.7 lbs/in (27.5 N/cm) and four springs with a spring rate of 23.4 lbs/in (41.0 N/cm) may be employed. To improve pitch stability, i.e., the tendency for treads  60  to pitch forward or back, the more rigid springs are placed at the front and back of tread  60  with the softer springs positioned in the more central locations. Six inch long springs with the above spring rates are commercially available; Diamond Wire Spring Company of Pittsburgh, Pa. produce and stock suitable springs having the spring rates mentioned above. Obviously, more springs with a smaller spring rate or fewer springs with a higher spring rate will achieve similar results. As mentioned earlier, each spring is preferably coated with an elastomer to reduce noise generated from spring vibrations. 
     Because treads  60  are not attached in any way to housing  12 , they “float” on springs  52 , and can tilt slightly forward and back in response to more weight being placed toward the front or back of the tread. This accommodates a person&#39;s natural stride; if an exerciser comes down on his or her heels, the treads  60  will respond and distribute the weight across the person&#39;s entire foot. This reduces the possibility for injury or discomfort that prior art devices can cause if used regularly. 
     The exemplary embodiment presents coiled compression springs for providing a return force to treads  60 . However, other types of springs are contemplated. For example, leaf-springs, torsion springs, and various other known springs shapes are all contemplated and easily integrated into housing  12 . 
     It is to be understood that the present invention is not limited to the embodiments described above, but encompasses any and all embodiments within the scope of the following claims.