Abstract:
A variable resistance exercising device is described for doing isometric, isotonic and isokinetic exercises. The device includes a unitary, tortuous rod, which is shaped to include at least one mandrel for receiving several turns of a rope, a first loop for receiving the rope near one end of the mandrel, and an overlapping curl for receiving both the rope and an adjustably mountable anchor strap at an opposite end of the mandrel. The shape of the rod is such that there are no tight radius curves. Also, the rod creates a cord-receiving throat that allows the rope to be readily inserted and removed; yet the throat inhibits the rope from falling out from within the loop when tension in the rope is released.

Description:
BACKGROUND OF THE INVENTION 
   1. Field of the Invention 
   The subject invention generally pertains to exercising devices and more specifically to a portable device that employs a selectable number of wraps for adjusting the device&#39;s frictional resistance. 
   2. Description of Related Art 
   Various portable fitness devices have been developed in the past. Perhaps one of the best ones is disclosed in U.S. Pat. No. 4,466,612, which is specifically incorporated by reference herein. 
   Although the device disclosed in the &#39;612 patent offers several advantages over other available devices, the &#39;612 device does have some drawbacks. First, the rope to which the handles are attached can slip off the lower loops of the device when the rope slackens. Second, the unitary bar includes several tight radius bends, which can be difficult to form without leaving kinks or marks in the surface of the bar. If such marks are not removed, they can cut the rope when the device is in use. 
   Consequently, a need exists for an improved portable fitness device that overcomes the problems of current devices. 
   SUMMARY OF THE INVENTION 
   To provide a superior portable fitness device, an object of some embodiments of the invention is to provide a unitary rod that is formed in a tortuous shape to create at least one overlapping curl that facilitates the installation and removal of a pliable elongate member such as a rope, cord, strap, cable, etc. 
   Another object of some embodiments is to provide a unitary rod that defines a restricted passageway through which the pliable elongate member can be forced, whereby the pliable elongate member does readily fall out on its own. 
   Another object of some embodiments is to create the restricted passageway at a location that is spaced apart from the very end of the unitary rod, thereby avoiding sharp edges that may exist at the end of the rod. 
   Another object of some embodiments is to form a portable fitness device from a unitary rod of a substantially uniform diameter so that the rod can be readily formed using conventional and N/C forming machines. 
   Another object of some embodiments is to produce a portable fitness device from a unitary rod that does not include any tight bends that are difficult to form. 
   Another object of some embodiments is to provide the formed unitary rod with a surface finish of at least 120 microinches, and preferably 250 microinches or more, to ensure ample frictional drag without having to wrap the pliable elongate member an excessive number of turns around the rod. 
   Another object of some embodiments is to provide a pliable elongate member with handles at each end that can be left on while inserting, adjusting or removing the pliable elongate member from the unitary rod. 
   Another object of some embodiments is to enable a user to adjustably anchor a portable fitness device between a door and a doorjamb and do so by using a flexible elongate anchor that is sufficiently soft to avoid damaging the door. 
   Another object of some embodiments is to provide a pliable elongate member that can be selectively attached or removed from a unitary bar without having to untie or unbuckle the elongate member. 
   One or more of these and/or other objects of the invention are provided by an exercise device that includes two pliable elongate members that are attached to a unitary rod. The rod has a tortuous shape to define a restricted passageway through which at least one of the elongate members can be forced. 

   
     BRIEF DESCRIPTION OF THE DRAWING 
       FIG. 1  is a front view of an exercise device according to one embodiment of the invention. 
       FIG. 2  is a side view of  FIG. 1 . 
       FIG. 3  is a front view of a unitary rod used in the device of  FIG. 1 . 
       FIG. 4  is a side view of  FIG. 3 . 
       FIG. 5  is a schematic view showing the use of the exercise device of  FIG. 1 . 
       FIG. 6  is a front view similar to  FIG. 3  but showing another rod embodiment. 
       FIG. 7  is a front view similar to  FIG. 3  but showing another rod embodiment. 
       FIG. 8  is a front view similar to  FIG. 3  but showing another rod embodiment. 
       FIG. 9  is a front view similar to  FIG. 3  but showing another rod embodiment. 
       FIG. 10  is a cross-sectional view taken along line  10 - 10  of  FIG. 9 . 
       FIG. 11  is a front view similar to  FIG. 1  but showing another embodiment of an exercise device. 
       FIG. 12  is a front view of a rod used in the exercise device of  FIG. 11 . 
       FIG. 13  is a side view of  FIG. 12 . 
       FIG. 14  is a front view of another embodiment. 
       FIG. 15  is a front view of yet another embodiment. 
   

   DESCRIPTION OF THE PREFERRED EMBODIMENT 
   An exercise device  10 , shown in  FIGS. 1-5 , can be used in a manner similar to that of the device disclosed in U.S. Pat. No. 4,466,612; however, device  10  includes features not found in earlier devices. In some embodiments, device  10  comprises a unitary rod  12 , a strap  14  and a cord  16 . Strap  14  helps anchor rod  12  to a doorjamb  18  ( FIG. 5 ) or some other convenient point, and cord  16  is threaded through and wrapped around rod  12  to create frictional drag between rod  12  and cord  16 . The number of wraps can be varied to adjust the amount of friction. To exercise, a user  20  alternately pulls on handles  22  and while maintaining at least some tension at both ends of cord  16 . The friction between rod  12  and cord  16  provides resistance that can be used in a wide variety of physical exercises. 
   The terms, “strap” and “cord” are defined herein as being equivalent and are thus used interchangeably. Both a “strap” and a “cord” represent any type of pliable elongate member. Examples of a strap include, but are not limited to, a belt, a rope, a cord, a fabric strip, a cable, etc. Likewise, examples of a cord include, but are not limited to, a belt, a rope, a strap, a fabric strip, a cable, etc. The terms, “strap” and “cord” are being used in the claims only to make the claims easier to read and understand, as the awkward alternative of using the terms, “a first elongate member” and “a second elongate member” would only add unnecessary confusion to the claims. 
   In some embodiments, rod  12  extends seamlessly from a first end  24  to an opposite end  26  to provide a unitary rod that comprises a first mandrel  28  with a first loop  30 , a second mandrel  32  with a second loop  34 , and an overlapping curl  36  interposed between mandrels  28  and  32 . 
   Overlapping curl  36  comprises a first lap  38  and a second lap  40  that overlap each other such that curl  36  defines an eyelet  42  into which strap  14  and cord  16  may extend. Laps  38  and  40  may also define a strap-receiving passageway  44  therebetween such that strap  14  can be slipped through passageway  44  to selectively insert and remove strap  14  from within eyelet  42 . Passageway  44  may be smaller than a strap thickness  46  of strap  14  so that in order to install strap  14  by sliding it through passageway  44 , strap  14  may need to be forced between laps  38  and  40  to encircle at least one of the laps. In cases where laps  38  and  40  are tightly up against each other, passageway  44  can still exist by virtue of rod  12  having sufficient flexibility to allow laps  38  and  40  to be momentarily forced apart to receive strap  14 . 
   First loop  30  is adjacent to first mandrel  28  to define a first cord-receiving throat  48  between loop  30  and mandrel  28 . The cord-receiving throat is defined as the minimum radial distance between the loop and its adjacent mandrel, wherein the radial distance is in reference to the radius or diameter of the rod itself (not the radius along which the rod is bent). Throat  48  is preferably smaller than a cord thickness  50  of cord  16  so that once cord  16  is forcibly slid through throat  48  and into loop  30 , cord  16  does not readily fall back out. Likewise, second loop  34  is adjacent to second mandrel  32  to define a second cord-receiving throat  52  between loop  34  and mandrel  32 . Throat  52  is also preferably smaller than cord thickness  50  so that once cord  16  is forcibly slid through throat  52  and into loop  34 , cord  16  does not readily fall back out. In some cases, the loop and adjacent mandrel are tightly up against each other, whereby forcing the two apart creates the throat. The flexibility of cord  16  and/or rod  12  enable the larger cord to be forced through the smaller throat. 
   In some cases, as shown in  FIG. 3 , first throat  48  is positioned a short distance from end  24  of rod  12  so that if a sharp edge exists at end  24 , that edge will be less likely to snag cord  16  as the cord is being inserted into first loop  30 . Thus, a lead-in for cord  16  is created by positioning end  24  a spaced distance  54  from first mandrel  28 , wherein distance  54  is greater than throat  48  (i.e., distance  54  is greater than the distance between loop  30  and mandrel  28  at throat  48 ). The same applies to second loop  34 , second mandrel  32  and second throat  52 . 
   To facilitate manufacturing, rod  12  has a substantially uniform diameter  56  along substantially the entire length of the rod. In addition, a tortuous longitudinal centerline  58  extending along a full length of rod  12  has a minimum radius of curvature  60  that is at least twice as large as diameter  56 , and is preferably at least three times as large as diameter  56 . The relatively large radius of curvature provides rod  12  with a smoothly curved surface along its full length, which makes rod  12  easy to form without creating kinks or other sharp edges in the rod. 
   To create ample frictional drag between cord  16  and rod  12  without having to use an excessive number of wraps, rod  12  preferably has a satin or roughened surface finish of at least 120 microinches, and preferably 250 microinches or more, wherein the microinch value is the average deviation from the mean surface as well understood by those of ordinary skill in the art of surface finishes. In some cases, a surface finish of 500 or even a 1,000 microinches may provide positive results. Such surface finishes can be accomplished by various ways including, but not limited to, machining, knurling, or sand blasting the surface of rod  12 . 
   To render strap  14  removable from rod  12 , a first end  62  of strap  14  can be provided with a strap loop  64  that can slip over loop  30  or  34  and slide through strap-receiving passageway  44  to the position of  FIGS. 1 and 2  so that strap loop  64  can engage either lap  38  or  40 . For a more permanent connection, strap  14  can be wrapped around both laps  38  and  40  and subsequently sewn at a seam  66  to create a strap loop that is not readily removable. 
   To enable a second end  68  of strap  12  to be adjustably anchored to a doorframe, strap  14  contains a plurality of flexible elongate anchors  70  that provide strap  14  with an enlarged strap thickness  72  at each anchor  70 . Strap  14  can be held pinched between a door  74  and its doorjamb  18 , as shown in  FIG. 5 . The thickness of anchors  70  prevents strap  14  from pulling out from within the doorjamb, and the multiple anchors  70  provide a means for selectively adjusting an effective length  76  of strap  14 . Anchors  70  can be made of neoprene tubing or some other relatively soft material to avoiding damaging the surface of door  74  or doorjamb  18 . 
   It should be appreciated that unitary rod  12  can assume an infinite variety of other configurations while still remaining within the spirit of the invention. Some alternate configurations, for example, are shown in  FIGS. 6-13 . 
   A unitary rod  78  of  FIG. 6  is similar to rod  12 ; however, loops  80  and  82  protrude outward rather than inward, and mandrels  84  and  86 , which correspond to mandrels  28  and  32 , are set at an angle to each other. 
   A unitary rod  88  of  FIG. 7  is similar to rod  12 ; however, an overlapping loop  90  has a more triangular shape with a flat upper section  92  that is suitable for engaging a wide strap, and a more pointed lower section  94  this is suitable for engaging a narrower cord. Also in this example, the very ends  96  and  98  of rod  88  help define throats  100  and  102 . 
   In  FIG. 8 , a unitary rod  104  has yet another shape for creating loops  106  and  108 . 
   A unitary rod  110  of  FIGS. 9 and 10  provides a particularly novel way of creating a cord-receiving throat  112 . In this example, loop  114  overlaps its adjacent mandrel  116  to create throat  112  therebetween that is smaller than cord thickness  50 . Loop  118  and mandrel  120  are formed in a similar manner. 
   In another embodiment, shown in  FIGS. 11-13 , a unitary rod  122  includes an overlapping curl  124  and a loop  126 , which are both formed similar to loop  114  of  FIGS. 9 and 10 . 
   The embodiment of  FIG. 14  shows how a handle  128  can be attached to cord  16  by using a releasable knot  130 . Knot  130  allows one to adjust the active portion of cord  16  that extends between the two handles. Being able to adjust the active cord length allows one to use the exercise device for a greater variety of exercises. When the active cord length is relatively short, the extra cord  16 ′ can simple drape beyond handles  28 . Knot  130  can be any suitable knot and not just limited to the one shown. The knot shown in  FIG. 14  is known as a Lark&#39;s Head Hitch, a Cow Hitch, or a Lanyard Hitch. It should be noted that an apex  140  of handle  128  provides an angle of convergence that creates a crevice that is narrower than the diameter of cord  16 , whereby the crevice pinches cord  16  to help hold knot  130  together. 
   In yet another embodiment, shown in  FIG. 15 , cord  16   a  is tied or wrapped around a centrally located groove  132  of a handle  134 . Any appropriate knot  138  can be used such as, for example, a Clove Hitch, Overhand Knot, or Thumb Knot. To maintain tension in cord  16   b  as user  20  pulls handle  134  in direction  136 , user  20  can pinch cord  16   b  between the user&#39;s finger  20   a  and thumb  20   b . Varying the pinching force against cord  16   b  varies the force required to pull handle  134  in direction  136 . Adjusting the location of knot  138  along the length of cord  16  provides a way of adjusting the active length of cord  4  or the distance between handle  34  and device  12 . 
   Although the invention is described with reference to a preferred embodiment, it should be appreciated by those of ordinary skill in the art that various modifications are well within the scope of the invention. Therefore, the scope of the invention is to be determined by reference to the following claims.