Abstract:
The abdominal exercise device is designed for upright orientation with a user bending forwardly and downwardly. An upper pivotal section moves relative to an upright base and a bias force is provided by torsion type bars. The particular pivot location and handle arrangement reduces the possibility of misuse and targets the abdominal muscles.

Description:
[0001]    This invention claims priority from the earlier-filed U.S. Provisional Application No. 60/935,450, filed on Aug. 14, 2007. 
     
    
     FIELD OF THE INVENTION 
       [0002]    The present invention relates to exercise devices, and in particular, to abdominal exercise devices. 
       BACKGROUND OF THE INVENTION 
       [0003]    Abdominal exercises are recommended for toning of the abdominal area, increasing the core strength of an individual, and alleviating back problems. The proper exercise of the abdominal muscles is often confused with the traditional sit-up, whereas in fact, exercise of the lower abdominal muscles requires a significantly different motion. 
         [0004]    Various portable exercise devices are well-known and a number of these devices are designed to assist a user in properly completing a sit-up. One such exercise device is shown in U.S. Pat. No. 5,871,425. This device is supported on the floor and the user performs the sit-up against a variable resistance that is adjustable by the user. 
         [0005]    U.S. Pat. No. 6,213,923 discloses an exercise device where a user in a sitting position pulls a pivoted backrest portion forwardly to perform a sit-up type exercise. The pivot position is generally at the base of the seat. 
         [0006]    There are a number of devices that have been proposed for use in combination with a traditional chair. One such device is shown in U.S. Pat. No. 6,110,081. 
         [0007]    More recently there has been a shift in emphasis from a sit-up type exercise to a crunch-type exercise for exercising the abdominal muscles. U.S. Pat. No. 6,296,598 shows a particular apparatus which is placed to the front side of the user sitting on a chair and the user effectively compresses the device by means of a forwarded pivoting action to form a crunch-type exercise. 
         [0008]    The present invention provides an exercise device that is easily supported on an upright chair or made as an integral part of a conventional chair such as a desk chair. 
       SUMMARY OF THE INVENTION 
       [0009]    An abdominal exercise device according to the present invention comprises an upright base connected to a pivoting upper section. The upper section includes two pivoting handles adapted to extend forwardly at an upper edge of the pivoting upper section in a perpendicular manner to provide hand grip extensions above the shoulders of a user used to pivot the upper section relative to the upright base. The upper section and the upright base include a variable bias arrangement adapted to provide a resisting force when the upper section is pivoted forwardly relative to the upright base. The upright base is of a length significantly greater than the pivoting upper section, such that a pivoting axis between the pivoting upper section and the upright base is generally located adjacent a lower edge of the shoulder blades of a user. 
         [0010]    According to an aspect of the invention, the bias arrangement includes replaceable torsion rods extending across the pivot axis and secured to the upright base and the pivoting upper section. 
         [0011]    In a further aspect of the invention, the upright base and the pivoting upper section each include at least three securement slots for retaining the replaceable torsion rods. 
         [0012]    In a preferred aspect of the invention, the upright base and the pivoting upper section each include a molded plastic structural support having the securement slots molded therein. 
         [0013]    In yet a further aspect of the invention, the replaceable torsion rods are inserted or removed through a top access slot of the pivoting upper section. 
         [0014]    In a preferred structure of the invention, the pivoting upper section and the upright base include a common upholstered front face including an inner foam cushion layer. 
         [0015]    In a different aspect of the invention, the upright base and the pivoting upper section each include opposed lugs including a pivoting port that receives a pivot shaft and forms part of the pivot axis. 
         [0016]    In yet a further aspect of the invention, the hand grip extensions are telescopic and lockable to set a hand grip extension appropriate for the user. 
         [0017]    In an aspect of the invention, the pivoting handles are movable between a storage position, with the hand grip extensions extending across a width of the upright portion at an upper edge thereof, to an exercise position, with the hand grip extensions generally perpendicular to the pivoting upper section. 
         [0018]    In yet a different aspect of the invention, the exercise device forms the backrest portion of a chair and preferably forms the backrest portion of an office chair. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0019]    Further embodiments of the invention are shown in the drawings, wherein: 
           [0020]      FIG. 1  is a schematic perspective view showing the abdominal exercise device supported on a chair with a user about to commence an exercising motion; 
           [0021]      FIG. 2  is a schematic similar to  FIG. 1  with the user having moved the exercise device to perform the initial step of the abdominal exercise; 
           [0022]      FIG. 3  is a partial exploded perspective view showing the interior components of the abdominal exercise device, and in particular, the torsion bars used to increase the resistance to the exercising motion; 
           [0023]      FIG. 4  is a schematic side view of the interior components of the exercise device; 
           [0024]      FIG. 5  is a partial front view showing an alternate pivot securement of the upright base portion to the pivoting upper section; 
           [0025]      FIG. 6  is a partial perspective view showing further details of a preferred hinge connection with limited rotation; 
           [0026]      FIG. 7  is a perspective view of the upholstered abdominal exercise device; 
           [0027]      FIG. 8  is a perspective view of a preferred telescoping handle arrangement; 
           [0028]      FIG. 9  is a schematic perspective view of the abdominal exercise device forming the back portion of an office-type chair; and 
           [0029]      FIG. 10  is a partial perspective view of an alternate handle arrangement. 
       
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
       [0030]    The abdominal exercise device  2  is shown supported on an office-type chair  90  in  FIGS. 1 and 2 . The abdominal exercise device is shown in an initial position in  FIG. 1  and in a pivoted forward position in  FIG. 2 . The exercise device includes an upright base portion  4  supported by a suitable chair and a pivoting upper section  6 . The user uses the pivoting handles  14  to pull the pivoting upper section forwardly as the upright base portion remains generally fixed. 
         [0031]    The perspective view of  FIG. 3  shows the interior components of the abdominal exercise device  2  including the upright base  4  and the pivoting upper section  6 . The telescopic handles  14  include a securing extension  15  and a hand grip extension  16 . These telescopic handles  14  are each received within a handle support  18  provided on the upper support  24 . The upper support  24  is pivotally secured to the bottom support  22  by a pivoting hinge  50 . This pivoting hinge forms a pivot axis  20  about which the upper support  24  pivots relative to the bottom support  22 . Preferably, the upper support  24  and the bottom support  22  are each of a molded plastic to include the handle supports  18  as well as the series of upper torsion bar supports  32  and lower torsion bar supports  34 . The torsion bar supports  32  and  34  can be of greater length to provide additional support of the torsion bars such that deflection primarily occurs adjacent the pivot axis  20 . Torsion bars  28  are easily inserted and removed from the supports  32  and  34 , allowing a simple mechanism for varying the force required to perform the pivoting motion. The torsion bars  28  extend across the pivot axis  20  and have a bias to the straight configuration shown in  FIG. 3 . The bars  28  are preferably made of a fiberglass, spring steel or reinforced plastic material. 
         [0032]    In  FIG. 4 , the side view shows the torsion bars  28  being deformed and providing resistance to the pivoting of the upper support  24  relative to the bottom support  22 . Three torsion bars  24  have been shown; however the device can be adapted to include additional bars or bars of varying strengths. In this way, a simple mechanism is provided allowing adjustment of the bias force such that the abdominal exercise device can be appropriately set for different users. The handles  14  are also height adjustable within handle supports  18  and are set according to the requirements of the user. Shown in dotted lines in  FIG. 3  is the upholstered exterior face of the exercise device indicated as  40 . This typically includes a compressible foam cushion portion and a suitable outer fabric portion. The exercise device is typically made to allow access to the back portion of the exercise device, or at least the upper end portion of the exercise device, to allow for convenient replacement of the torsion bars  28 . 
         [0033]    Details of a preferred pivoting hinge arrangement are shown in  FIGS. 5 and 6  with  FIG. 6  also illustrating a pivot limiting lock. The pivoting hinge  50  includes a pivot shaft  52  having threaded end portions  54 . These threaded end portions receive the upper pivoting lugs  56  and also receive the lower pivoting lugs  58  on the threaded portions. Threaded knobs  60  retain the pivoting lugs on the pivot shaft  52 . Other arrangements for forming the pivot axis are also possible. The upper pivoting lugs  56  are shown with a large gap  55  adjacent the pivot shaft  52 . This accommodates pivoting and avoids the compressible foam or upholstered fabric pinching the user. The bottom pivoting lugs could also be of a longer length to avoid this tendency if necessary. 
         [0034]    The upper pivoting lugs  56 , as shown in  FIG. 6 , include stop projections  57  that engage stop lugs  59  of the lower pivoting legs  58 . The stop projections  57  and the stop lugs  59  cooperate to limit the angle of forward pivoting of the pivoting upper section  6  relative to the upright base portion  4 . The preferred maximum angle of rotation is in the range of 30 degrees to 40 degrees. Further rotation is not beneficial and may be counter productive. Although a fixed rotation limiting arrangement is shown it could be adjustable to be varied by the user. 
         [0035]    As shown in  FIG. 7 , the abdominal exercise device  2  has the pivot axis  20  at a relatively high position adjacent to generally correspond to the shoulder blade height of the user. This provides a pivoting action of the user at a much higher location than would be the case with respect to a sit-up type exercise. This pivoting exercise of the user at the higher location strengthens the abdominal muscles and also helps alleviate back problems associated with the muscles adjacent the lower portion of the back. The telescopic handles  14  are height adjustable as they telescope within the handle supports  18  of the exercise device. Preferably, the handles also telescope as shown in  FIG. 8 , such that the hand grip  16  is of variable length by means of adjusting the first segment  16 a relative to the second segment  16 b. This dual adjustment allows the exercise device to be adjusted to suit different physical attributes of the particular users. In addition, it allows the hand grip  16  to be reduced in length and easily stored across the top of the exercise device. 
         [0036]    The upright base portion  4  is typically placed in a chair, and due to the particular high pivoting action, the user tends to force this upright portion back into contact with the upright portion of the seat. In this way, it is often not necessary to include a strap maintaining the upright portion  4  against the upright portion of the chair. Such a strap can be provided if desired. In one embodiment as shown in  FIG. 7 , a removable seat portion  100  is releasably attached to the upright base portion  4 . 
         [0037]    An alternate handle embodiment is shown in  FIG. 10  where rope handles  17  have replaced the “L” shaped rigid handles  14 . The rope handle  17  includes an adjustable limiting member  17 a that could be a separate slidable lockable member or could be a large knot in the rope handle. The user appropriately adjusts the flexible handles  17  for his physical requirements. There is a preferred position of the user&#39;s arms and elbows such that the hands are either side of the user&#39;s head and between his shoulders and ears. 
         [0038]    The flexible handles avoid the tendency of a user to use leverage and his arms to complete the exercise rather than the abdominal muscles. The arms basically form a force transfer linkage between the pivoting upper section  6  and the user&#39;s abdominal muscles. There should be no significant use of the arms to cause pivoting and the rope handles reduce this possibility. 
         [0039]    To use the device, the user positions himself to have his back in contact with the upright base portion  4  and reaches rearwardly to engage the handles  14 . The user then pulls on the handles to pivot the upper support  24  about the hinge axis  20 . The upright base portion  4  of the abdominal exercise device is maintained in the upright position and remains motionless while providing a lordotic support position (normal lumbar curvature for the user). Therefore, the lumbar spine does not participate in the exercise. This is a fundamental difference, in that many studies over the years have shown that a sit-up/crunch maneuver with flexion at the waist produces a shearing effect on the spinal facet joints and a posterior disc stress (bulging) on the lumbar discs. This device virtually eliminates these stresses, thereby achieving a safer exercise. Another fundamental difference is evidenced in that prior art abdominal devices do not support the lumbar spine in a normal lordotic configuration and do not produce a shortening of the contracting muscles by virtue of flexion at the waist, and do not achieve an overall strengthening of the abdominal musculature through a complete range of motion. 
         [0040]    With the devices shown, the user can adjust the resistance required to pivot the upper support  24  relative to the bottom support  22  by adding additional torsion bars. The pivot point is higher on the user&#39;s back, and the forward motion of the user against the resistance exercises (concentrically and eccentrically), the desired abdominal muscles including the rectus abdominus, intertransversaii, internal and external obliques and serratus anterior, while minimizing involvement of the hip flexors. 
         [0041]    This abdominal exercise device can advantageously be used with existing chairs, such as office chairs, work station chairs, kitchen chairs, television room chairs, dining room chairs, etc. to allow a user a simple, low cost device for performing a consistent crunch exercise. The device is economical, durable and small in size thereby simplifying storage when not in use. It can remain in one chair indefinitely, as it is contoured as a lumbar support. 
         [0042]    The abdominal and back machine has been shown as being an add-on for use with an existing chair, however it can be appreciated that this exercise device with the retractable handles can be built in as part of a conventional office, desk chair or specialized exercise chair as shown in  FIG. 8 . In this way, particularly for office chairs, a person who is generally performing a desk job can use the exerciser as an add-on device or as an integral device part of his normal chair to perform crunch exercises from time to time. This particular arrangement can be integral with the chair and as such is unobtrusive. The retractable handles and the pivoting point at a raised position on the chair can all be concealed to provide an effective office chair with a pleasing appearance appropriate for normal office requirements. In addition the desired lumbar support is provided. 
         [0043]    The particular design of this abdominal exercise device, and in particular, the high pivot axis location, assists the user in isolating the appropriate muscles for strengthening the abdominal area and increasing the core strength of the user. Many exercise devices fail to effectively strengthen these muscles. Typically the upright base portion  4  is of a height at least two to three times the height of the pivoting upper section  6 . 
         [0044]    Although various preferred embodiments of the present invention have been described herein in detail, it will be appreciated by those skilled in the art, that variations may be made thereto without departing from spirit of the invention or the scope of the appended claims.