Patent Publication Number: US-8974351-B2

Title: Bi-directional wrist exercise device

Description:
BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The present invention relates to a wrist exercise device, in particular, a wrist exercise device used for strengthening the muscles of the forearm. 
     2. Description of Related Art 
     Devices adapted to exercise the muscles of the aim are known in the art. See, for example, the wrist exercise device disclosed in U.S. Pat. No. 4,770,409 to Wallisch, which is hereby incorporated by reference as if set forth in its entirety herein. As shown in  FIG. 1 , which shows the device disclosed in U.S. Pat. No. 4,770,409, the prior wrist exercise device includes a housing formed in a figure eight shape and with adjacent circular portions  105  having an annular channel, an arcuate slide  110  positioned within the channel and in slidable engagement therewith, a grip handle  114  extending across an inner area of each circular portion  105  and connected to one of said arcuate slides  110 , a stop  116  positioned within each annular channel and disposed adjacent one end  111  of each of said arcuate slides  110 , and spring means  118  positioned within each annular channel and extending between said stop  116  and the other end  112  of each of the arcuate slides  110 . That is, each grip handle  114  is pushed against the stop  116  at a locked position. When using this prior wrist exercise device, the grip handles  114  are grasped by user&#39;s hand in a locked position and are turned against the resistance of the spring means  118 . For example, the left handle  114  is turned counter-clockwise (direction A in  FIG. 1 ), and the right handle  114  is turned clockwise (direction B in  FIG. 1 ). Then, the grip handles  114  are returned to the locked position as user loosens his or her force. 
     However, when the user wants to strengthen the different muscles that are used for opposite rotation of his or her wrist, the device has to be turned over, and the grip handles  114  are grasped again by user&#39;s hand in a locked position. Then, the grip handles  114  are turned against the resistance of the spring means  118 . For example, the left handle is turned clockwise, and the right handle is turned counter-clockwise. 
     SUMMARY OF THE INVENTION 
     According to a particular, non-limiting embodiment of the present invention, a wrist exercise device is provided, which allows for an effective exercise of the muscles of the forearm through rotation of the wrist against spring provided resistance in opposing directions. 
     According to one embodiment of the present invention, a wrist exercise device is provided. The wrist exercise device includes a housing having circular portions; a grip handle extending across an inner area of each circular portion of the housing, with both ends of each grip handle engaged rotatably in a circular direction with the circular portion of the housing; and at least one spring positioned within each circular portion of the housing. The at least one spring engages the grip handle and the housing to increase an elastic force of the spring between the grip handle and the housing when the grip handle rotates in any direction. 
     The at least one spring arranged in each circular portion includes a first spring and a second spring. The elastic force of the first spring between the grip handle, and the housing is increased when the grip handle rotates in one direction, and the elastic force of the second spring between the grip handle and the housing is increased when the grip handle rotates in another direction. One end of the first spring may be connected to one end of the grip handle and one end of the second spring may be connected to another end of the grip handle. The first spring and the second spring may be configured to have a same length and same elasticity. 
     The wrist exercise device may further include a stop positioned within each circular portion and being configured to fix the first spring and the second spring on the housing. 
     The grip handle arranged in each circular portion may include an arcuate slide portion, and each circular portion of the housing may have an annular channel defined therein. The arcuate slide portion may be positioned within the annular channel of each circular portion of the housing and may be slidably engaged therewith. 
     According to another embodiment of the present invention, a wrist exercise device is provided. The wrist exercise device includes a housing formed with adjacent circular portions, with each circular portion of the housing having an annular channel defined therein; a grip handle extending across an inner area of each circular portion of the housing, with each end of the handle positioning within the annular channel of each circular portion of the housing and in slidable engagement therewith; a stop positioned within each annular channel; a first spring positioned within each annular channel and extending between the stop and one end of the respective handle; and a second spring positioned within each annular channel and extending between the stop and the other end of the respective handle. 
     According to another embodiment of the present invention, a wrist exercise device is provided. The wrist exercise device includes a housing formed in a figure eight shape and with adjacent circular portions, with each circular portion of the housing having an annular channel defined therein; an arcuate slide positioned within the annular channel of each circular portion of the housing and in slidable engagement therewith; a grip handle extending across an inner area of each circular portion of the housing and connected to one of the arcuate slides; a stop positioned within each annular channel; a first spring positioned within each annular channel and extending between the stop and one end of the respective arcuate slide; and a second spring positioned within each annular channel and extending between the stop and the other end of each of the respective arcuate slide. 
     The housing may be formed of a top housing removably secured to a bottom housing, with the top and bottom housings each having a pair of annular grooves formed therein, with the annular grooves together forming the annular channels when the top and bottom housings are secured together and the annular grooves are aligned. Inner peripheral edges of the circular portions of the top and bottom housings may be spaced apart from each other and the arcuate slides may each have an inwardly directed shoulder which extends through the space between the inner peripheral edges. 
     Further details and advantages of the invention will become clear upon reading the following detailed description in conjunction with the accompanying drawing figures, wherein like parts are designated with like reference numerals throughout. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a top plan view of a prior art wrist exercise device; 
         FIG. 2  is a top view of a wrist exercise device according to one embodiment of the present invention; 
         FIG. 3  is a cross-sectional view of the wrist exercise device shown in  FIG. 2 ; 
         FIG. 4  is a top plan view of a wrist exercise device according to one embodiment of the present invention; 
         FIG. 5  is a top plan view of the wrist exercise device shown in  FIG. 4 , showing a situation where the grip handle is rotated in one direction. 
         FIG. 6  is a top plan view of the wrist exercise device shown in  FIG. 4 , showing a situation where the grip handle is rotated in another direction. 
     
    
    
     DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     For purposes of the description hereinafter, the terms “end”, “upper”, “lower”, “right”, “left”, “vertical”, “horizontal”, “top”, “bottom”, “lateral”, “longitudinal” and derivatives thereof shall relate to the invention as it is oriented in the drawing figures. However, it is to be understood that the invention may assume various alternative variations and step sequences, except where expressly specified to the contrary. It is also to be understood that the specific devices and processes illustrated in the attached drawings, and described in the following specification, are simply exemplary embodiments of the invention. Hence, specific dimensions and other physical characteristics related to the embodiments disclosed herein are not to be considered as limiting. Further, it is to be understood that the invention may assume various alternative variations and step sequences, except where expressly specified to the contrary. 
     Referring to  FIGS. 2-4 , one embodiment of a wrist exercise device  1  includes a housing  11  having a pair of circular portions  12  and  14  which are connected to each other, a pair of grip handles  16  and  18  engaged in each circular portion  12 ,  14  of the housing  11 , a pair of arcuate slides  31  and  36  slidably engaged with each circular portion  12 ,  14  of the housing  11 , and springs  41 - 44  positioned within each circular portion  12 ,  14  of the housing  11 . 
     In this embodiment, the circular portions  12  and  14  are arranged adjacently, hence the housing  11  is formed in a figure eight shape. The housing  11  is preferably formed in two parts, namely, top housing  47  and bottom housing  48 , which are joined together to form a rigid, unitary housing structure. Top housing  47  may be joined to bottom housing  48  by known fastening means, such as screws, rivets, bolts, glue or the like. Wider reinforcement areas  28  and  28  may be provided in the housing where the circular portions  12  and  14  are close to each other. In the reinforcement area  28 , the top housing  47  and the bottom housing  48  are preferably fastened by a reinforcement screw  55 . 
     Each circular portion  12 ,  14  includes an interior annular channel defined by the top housing  47  and the bottom housing  48  when connected. In this embodiment, each circular portion  12 ,  14  of the top housing  47  respectively includes an annular groove  21 ,  22 , formed about the inner periphery thereof. Likewise, each circular portion  12 ,  14  of the bottom housing  48  also respectively includes an annular groove  25 ,  26  formed about the inner periphery thereof. When the top housing  47  and bottom housing  48  are secured together, the annular grooves  21  and  22  of the top housing  47  are aligned with the annular grooves  25  and  26  of the bottom housing  48 , respectively. The grooves  21  and  25  in one circular portion form the annular channel in one circular portion  12  and the grooves  22  and  26  in another circular portion form the annular channel in another circular portion  14 . As shown in  FIGS. 3 and 4 , the grooves are preferably semi-circular in cross section and, as a result, the annular channels in circular portions  12 ,  14  are preferably circular in cross section. 
     In this embodiment, stops  51  and  52  are positioned within each annular channel and are fixed firmly to the housing  11 . The stops  51 ,  52  may be configured to be able to secure one end of the springs  41 - 44  to the housing  11 . The stops may be formed by known stopping means, such as screws, bolts, rigid plates formed as metal or plastic disks, or the like. One manner of affixing the one end of the spring to the housing is to provide a screw with an engaging member (not shown) which is configured to be able to catch the one end of the spring and is fixed to the housing by the screw. In another embodiment, the stops may be configured to be able to secure one end of the springs when the springs are compressed. For example, disk-type stops, having larger circumference than the annular grooves and being fixed to a slot cut perpendicular to the annular grooves, are used for this purpose. 
     The stops  51  and  52  may be adjustably positioned at any location within the annular grooves and, thereby, result in a change in the annular position of the grip handles  16  and  18  relative to the housing  11 . Other stop devices, such as inwardly directed tabs and the like, may also be used to secure one end of the springs. 
     Furthermore, the stops  51  and  52  of this embodiment are screws which are also able to fasten the top housing  47  and the bottom housing  48 . 
     The arcuate slides  31  and  36  are positioned within the annular channel of the circular portions  12  and  14  of the housing  11  respectively and can freely slide therein. In addition, grip handles  16  and  18  extend across an inner, open area of the circular portions  12  and  14  respectively and are securely affixed to associated arcuate slides  31  and  36 . As shown in the figures, arcuate slide  31  is positioned within the annular channel in circular portion  12 , and grip handle  16  is connected thereto and extends across the inner area of circular portion  12 . Similarly, arcuate slide  36  is positioned within the annular channel in circular portion  14 , and grip handle  18  is connected thereto and extends across the inner area of circular portion  14 . 
     The spring, such as a compression resistant coil spring, a torsion spring, an elastic member, a pneumatic or hydraulic piston and cylinder device, or the like, is positioned within the annular channel of each circular portion. In this embodiment, two coil springs  41 ,  42  or  43 ,  44  are positioned within the annular channel of each circular potion  12 ,  14 . Each coil spring  41 - 44  extends along the channel between the stop  51 ,  52  and the end of each arcuate slide  31 ,  36 . More specifically, one coil spring  41  extends from one side of the stop  51  to the one end of the arcuate slide  31 , and another coil spring  42  also extends from another side of the stop  51  to another end of the arcuate slide  31 , in one circular portion  12 . Likewise, one coil spring  43  extends from one side of the stop  52  to the one end of the arcuate slide  36 , and another coil spring  44  also extends from another side of the stop  52  to another end of the arcuate slide  36 , in another circular portion  14 . 
     According to one embodiment, one end of each coil spring may be fixed to the stop, and another end of each coil spring may be fixed to the arcuate slide, so that the springs cannot only provide resistance to compression, but also provide resistance to stretching. According to this structure, two springs located on both sides of the stop can provide the resistance to the arcuate slide at the same time when the grip handle is rotated. In this embodiment, the wrist exercise device can provide stronger resistance. 
     In another embodiment, the end of the coil spring may not be fixed to the stop or the arcuate slide, so that the spring can provide only resistance to compression. According to this structure, only one of two springs in each circular portion which is compressed can provide the resistance to the arcuate slide when the grip handle is rotated. In this embodiment, the wrist exercise device can provide weaker resistance. 
     Preferably, each spring has the same length and same elasticity as that of others. In this case, as shown in  FIG. 4 , at the neutral position, the arcuate slides  31 ,  36  are located on opposite sides of the stops  51 ,  52 . 
     When the top housing  47  is joined to the bottom housing  48 , the outer peripheral edges are in contact with each other. However, the inner peripheral edges are spaced apart and do not contact each other. As shown in  FIGS. 3 and 4 , an inner peripheral edge  61  of the top housing  47  in one circular portion  12  is spaced from the adjacent inner peripheral edge  63  of the bottom housing  48  in one circular portion  12  and an inner peripheral edge  62  of the top housing  47  in another circular portion  14  is spaced from the adjacent inner peripheral edge  64  of the bottom housing  48  in another circular portion  14 . Each arcuate slide  31 ,  36  has an inwardly directed shoulder  32 ,  37  which extends through the inner peripheral spacing between the top housing  47  and the bottom housing  48 . As shown in  FIGS. 3 and 4 , arcuate slide  31  has inwardly directed shoulder  32  integral therewith which extends between peripheral edges  61  and  63 . Likewise, arcuate slide  36  has an inwardly directed shoulder  37  integral therewith which extends between peripheral edges  62  and  64 . Preferably the shoulders  32 ,  37  are substantially flush with the peripheral edges  61 - 64 . In this manner, the arcuate slides  31  and  36  may securely move within the annular channels and be fastened to the grips  16  and  18 , and the grips  16  and  18  may be rotated within the inner area of each circular portion without frictionally contacting the housing. 
     Each arcuate slide  31 ,  36  preferably extends along one-half the circumferential length of the associated annular channel. The springs  41 - 44  will occupy the remainder of the annular channels, except for the space occupied by the stops  51 ,  52 . The springs  41 - 44  each have a diameter less than or the same as the diameter of the annular channels in which they are positioned. 
     In this embodiment, while two springs are used in each annular channel, one continuous spring can be used alternatively. In this case, the center portion of the one continuous spring is fixed to the housing by the stop, and both sides of the center portions are configured to be able to provide a resistance to the arcuate slide respectively. The end of the continuous coil spring may be preferably fixed to the arcuate slide. 
     In a preferred embodiment, the grips  16  and  18  are inclined toward each other at a 45° angle. As shown in  FIG. 4 , grip  16  is angled inwardly toward a similarly angled grip  18 , both at a 45° angle. The particular angular position of the slide/grip combination can be easily adjusted by changing the position of the stop in a particular annular groove. 
     The housing  11  and the slides  31 ,  36  are formed of a material having high stress resistance and high friction resistance, such as plastic, metal, wood, or the like, with plastic being preferred. The grips  16 ,  18  are formed of a material which can withstand the torque created as the arcuate slides  31 ,  36  are rotated against the springs  41 - 44 , such as plastic, metal, wood or the like. 
     The arcuate slide/grip combination may be formed of the same material in a unitary structure, such as molded plastic, or may be formed of different materials. A structure having a plastic arcuate slide joined to a wooden grip has proven to be satisfactory. The grips  16  and  18  may each be provided with a plurality of finger indentations, preferably four on each grip, to improve the gripping surface thereof. Alternatively, the grips may be provided with a knurled surface or coated with a grip enhancing material. 
     In practicing the wrist exercise device of the present invention, the grips  16  and  18  are grasped by a user&#39;s hand with the wrist in a neutral position as shown in  FIG. 4  and then turned inwardly or outwardly. The turning of the hands rotates each arcuate slide  31 ,  36  against the associated springs. More specifically, when grip  16  is rotated clockwise as shown by arrow A 1  in  FIG. 5  and grip  18  is rotated counterclockwise as shown by arrow B 1  in  FIG. 5 , the springs  42  and  44  are compressed and the springs  41  and  43  are stretched. The force of rotation will meet with increasing resistance as the compression and the stretching of the springs from their normal positions increase. Upon completed compression and stretching of the springs, the wrist is returned to its relaxed position, thereby releasing the compression and stretching and allowing the springs to be a normal length at the neutral position as shown in  FIG. 4 . 
     And then, according to the present invention, the grips  16  and  18  can be turned in opposite directions without turning over the entire device  1 . More specifically, grip  16  can be rotated counterclockwise as shown by arrow A 2  in  FIG. 6 , and grip  18  can be rotated clockwise as shown by arrow B 2  in  FIG. 6 . In this case, the springs  42  and  44  are stretched and the springs  41  and  43  are compressed. The force of rotation will meet with increasing resistance as the compression and the stretching of the springs from their normal positions increase. Upon completed compression and stretching of the springs, the wrist is returned to its relaxed position, thereby releasing the compression or stretching and allowing the springs to be a normal length at the neutral position as shown in  FIG. 4 . 
     As a result, the user may rotate his or her wrist in both inward and outward directions continuously without turning over the device, so the user can strengthen his or her muscles effectively. Therefore, according to the present invention, a wrist exercise device which allows for an effective exercise of the muscles of the forearm is provided. Furthermore, the present invention may be used in any position, horizontal, vertical, or intermediate, and both wrists may be exercised simultaneously, or each wrist may be exercised individually. Regardless of the specific training method used, if a routine of compression and relaxation of the spring is practiced, the hand muscles, wrist muscles, and forearm muscles will be effectively exercised. 
     Although the invention has been described in detail for the purpose of illustration based on what is currently considered to be the most practical and preferred embodiments, it is to be understood that such detail is solely for that purpose and that the invention is not limited to the disclosed embodiments but, on the contrary, is intended to cover modifications and equivalent arrangements that are within the spirit and scope of the description. For example, it is to be understood that the present invention contemplates that, to the extent possible, one or more features of any embodiment can be combined with one or more features of any other embodiment.