Abstract:
An improved device for athletic exercise by pulling at a resisting force. The device consists of a number of spring housing assemblies that are stacked and clamped in a column with at least one pulley wheel assembly to which a cord and pull handle is attached. A grooved metal shaft is disposed throughout the column longitudinal axis to drive all the constant-force spring assemblies which are stacked inside the device when the pulley wheel is caused to rotate. A person uses the device by first selecting which spring assemblies he wants to produce a particular resisting force level, by pushing separate selector levers, one for each spring. He then pulls at the pull handle to experience the chosen resisting force. The device design allows a user the choice of many resisting force levels, using only a small number of spring assemblies. The device is small, light in weight and conveniently shaped for easy attachment to any suitable restraining object.

Description:
THIS APPLICATION CLAIMS THE BENEFIT OF PROVISIONAL APPLICATION NO. 60/572,415 FILED May 20, 2004 

   BACKGROUND OF THE INVENTION 
   1. Field of the Invention 
   This invention relates to equipment used for athletic exercise, and more particularly, to portable devices used to exercise and strengthen the muscles by pulling. 
   2. Background 
   A portable athletic exerciser pulling device was invented earlier and is described in U.S. Pat. No. 5,505,681 by Bruggemann, who is one of the present inventors. This patented device consists of a small cylindrical housing enclosure containing a number of constant force, circular wound spring assemblies; and includes a cord-wound pulley wheel with a pull handle, that is molded to the enclosure and an attached force selector mechanism. The selector is used to manually select the number of spring assemblies to be engaged by the pulley, by inserting and moving a splined rod axially to connect in turn with the axially stacked spring assemblies. 
   When the pull handle is pulled, the device housing rotates around its cylindrical axis as do all the spring assemblies inside the housing. However, the total resisting force felt by a user is determined by the number of spring assemblies selected, as well as their individual constant force ratings. 
   If five spring assemblies are contained in the housing, then the maximum number of resisting force levels available to a user is also five. This is due to the sequential method of spring assembly selection employed by the device. 
   While the device described above has performed admirably and has been well received by users, the inventors believe that the number of resistance force levels made available by the device is unnecessarily limited, and the device remains more costly to produce than desired. There is, therefore, a need to improve upon the design of the device to extend the device versatility and at the same time, decrease the cost of the device. 
   SUMMARY OF THE INVENTION 
   The invention is an improvement of an exerciser pulling device which is described in U.S. Pat. No. 5,505,681 by Bruggemann. The invention is a small device which may be fastened to any suitable immovable object, and having a pull handle attached to a cord which is wrapped around a pulley wheel inside the device. The device comprises a plurality of spring housing assemblies that are stacked and clamped in a column with at least one pulley wheel assembly; and a grooved metal shaft that is disposed throughout the column longitudinal axis, engaging the hubs of all constant-force spring assemblies which are stacked inside the housing assemblies and engaging the pulley wheel hub. Means are provided for user manual selection of any individual spring assembly through slots in the side of the housing assemblies. Selection causes a selected spring assembly to generate a resisting force when the pull handle is pulled away from the device by an exerciser. 
   An advantage and improvement is that any one of the spring assemblies and any combination of the available spring assemblies can be selected by an exerciser, permitting a large number of force settings to be available for even relatively few total spring assemblies in a device. 
   Another advantage is the improved convenience of being able to fasten the device directly to any convenient immovable object without need for clamps. 
   Yet another advantage is the low cost of the invention device as compared with earlier devices. 
   Accordingly, it is a principal object of this invention to provide a large variety of resisting force settings available to a user of the device. 
   Another object is to improve the earlier device by greatly simplifying the device construction and reducing the number of parts required. 
   Further objects and advantages of the invention will be apparent from studying the following portion of the specification, the claims and the attached drawings. 

   
     BRIEF DESCRIPTION OF THE DRAWINGS 
       FIG. 1  is a perspective view of a preferred embodiment of an exerciser pulling device according to the present invention; 
       FIGS. 2 and 3  are plan views of a portion of the device taken along the plane defined by line  2 — 2  of  FIG. 1 , particularly showing in  FIG. 2 , an unselected spring assembly and showing in  FIG. 3 , a spring assembly that is selected and engaged by a selector lever; 
       FIGS. 4 and 5  are respectively, a top view of a spring base and a side elevation view taken along line  5 — 5  of  FIG. 4 ; 
       FIGS. 6 and 7  are respectively, an top end view of a spring assembly hub and a side elevation view of the hub; 
       FIGS. 8 and 9  are respectively, a side view and a top plan view of an external end cap which fits on the extreme ends of the device, particularly showing ears and earholes for clamping the device together; 
       FIGS. 10 and 11  are respectively, a side elevation view and an end view of a spring housing member, particularly showing lateral slots in one side for accessing stored spring assemblies; 
       FIGS. 12 and 13  are respectively, a top view and a side elevation view of a coupling end cap that is used to cap an open end of a spring housing assembly for coupling to another assembly; 
       FIGS. 14 and 14A  are respectively, a partial, side view and an end view of an elongate metal shaft that is grooved to connect and engage all the rotatable components that are stacked axially in the device; 
       FIG. 15  is a perspective view of a pulley wheel assembly; and, 
       FIGS. 16 ,  17  and  18  are respectively, a top view, an open side view and a bottom view of pulley wheel holder, particularly showing a semi-circular deep recess for seating a pulley wheel, allowing it to rotate freely. 
   

   DESCRIPTION OF THE PREFERRED EMBODIMENT 
   Referring particularly to the drawings, there is shown in  FIG. 1 , a preferred embodiment of an exerciser pulling device according to the present invention. The exerciser pulling device is simply constructed, and comprises one or more spring housing assemblies that are stacked in-line with one or more pulley wheel assemblies. Pulling a cord that is attached to a pulley wheel, produces an opposing, resisting force that is created by selected spring assemblies in each spring housing assembly. 
   The device is designed to be clamped or fastened to a fixed object such as a desk and used for manual pulling exercise. If needed for fastening, metal rings may be attached to the device end caps  2  for this purpose. A pull handle  18  is attached to the pulley wheel cord  20  and normally hangs down when not in use. If the device was being used for exercise, its pull handle  18  would be extended outwards as illustrated in  FIG. 1 , In the preferred embodiment shown in  FIG. 1 , a pulley wheel assembly  8  is shown sandwiched axially between two identical, spring housing assemblies. Each spring housing assembly is a capped, spring housing member  4  that contains a number of axially stacked, constant-force spring assemblies  24 . Lateral slots are cut in one longitudinal face of the spring housing member  4  which is designated as a control face  33 . These slots are arranged to be each co-planar with a spring assembly and to accommodate selector levers  16 , one in each slot. The levers are employed to separately select and engage any individual spring assembly  24  to resist a pull exerted by a user. 
   Each spring housing member  4  is capped by an external end cap  2  and a coupling end cap  6 . Both types of end cap serve primarily to secure the spring assemblies  24  which float, stacked in a central cylindrical cavity in each spring housing member  4 . However, the coupling end cap  6  is designed to also interface with a pulley wheel assembly  8  as depicted in  FIG. 1  or alternatively, with another spring housing assembly, which may be added in line. 
   A grooved metal shaft  32  is inserted centrally along the long axis of the cylindrical cavity in each spring housing  4 , and extends from one end of the device to the other; with the shaft ends being held loosely in a center recess in each of the external end caps  2 . The shaft  32  directly engages the pulley wheel  92  and a hub  30  of each spring assembly  24  so that a rotation of the pulley wheel  92  will cause all spring assemblies to rotate the same amount. However, unless engaged by a selector lever  16 , no resisting force will be generated by a spring assembly  24 . 
   Two end-threaded metal bolts  10  with a winged lock nut on each end, are used as a means of clamping the spring housing assemblies and a pulley assembly  8  together in a column. The winged lock nuts may include a handle portion  12  as illustrated, to aid with tightening or may instead, include a projecting metal ring portion for fastening the device to a fixed, immovable location. 
   A metal alignment rod  14  closely fills a channel that extends from one external end cap  2  to the device distal external end cap  2 , and another identical rod  14  occupies a parallel channel. These channels are formed by through-holes cut in the end caps, the spring housings and the pulley assembly, which are lined up axially during assembly. The alignment rods  14  in the channels, are provided to align each stacked assembly in a precise lateral position that lines up the rotational axis of all rotating components with the central shaft  32 , and prevents any possible lateral shifting that might otherwise occur during use of the device and so disrupt operation. 
   In the  FIG. 1  illustration, only half of the spring assemblies  24  in each spring housing member  4  have been selected and the corresponding spring assemblies engaged. This is easily ascertained by observing the selector levers  16  in the slots at the device control face  33 . Selector levers  16  that are shown with a long arm edge protruding out of a slot have not been selected. The levers  16  that are shown mostly inside a slot, have been manually selected by pushing the normally protruding lever end inwards with a finger tip. 
   All the selector levers  16  will have, visibly imprinted on their outer edge, a number indicating the force rating of the spring assembly it will engage. Thus, a user can pick any particular resisting force he desires by pushing the levers that add up to the total force desired. Sequential selection is not required. If each spring assembly is rated differently, the total number of resistance force levels available for selection by a user, increases as the square of the number of spring assemblies that are contained in the device. Thus a device containing only six spring assemblies could have as many as thirty-six resistance force levels available for choice in exercising. 
     FIGS. 2 and 3 , are cross-section views of the device taken along line  2 — 2  of  FIG. 1 , and are presented to explain how each spring assembly  24  is engaged by a selector lever  16 , and how a constant force is generated by an engaged spring assembly. 
   These two views show a spring assembly  24  that is fitted in a housing axial cavity  26  at a slot  72  level, and a pivotable selector lever  16  that is mounted on a pivot rod  34  on a slot surface that is adjacent to the control face  33  edge. 
   In  FIG. 2 , a spring assembly  24  is shown as unselected and unengaged. The selector lever  16  is shown with its longer arm  41  oriented away from the gear-tooth shaped periphery of the spring assembly  24 , so that a projecting spike  37  on the lever  16  can not enter one of the adjacent openings  39  in the spring assembly  24  periphery. In this lever position, a rotation of the axial shaft  32  will start to rotate the keyed hub  30  which fits loosely in the spring base  44 . Since one end of the coil-wound spring  28  is held by the hub  30  and the spring base  44  is free to rotate, the spring base will rotate with the hub  30 . No significant resisting torque will be generated because the amount of pulling force exerted by the hub on the end of the spring  28  will be minor. 
   In  FIG. 3 , a spring assembly  24  is shown as selected and engaged. The longer arm  41  of the selector lever  16  is shown as being oriented closely toward the peripheral spaced teeth around the spring base  44 , and the lever spike  37  is received by one of the openings  39  between the peripheral teeth; firmly engaging the spring base  44  and preventing its rotation. 
   In the selector position shown in  FIG. 3 , any rotation of the shaft  32  will rotate the hub  30  accordingly which will in turn, pull the hub end of the spring  28  without rotating the spring base  44  which is now held fixed. A constant force torque will thus be generated, with a magnitude depending on the spring  28  rating. 
   A commonly available means for temporarily holding the long arm  41  of a selector lever  16  in the selected positions, is the use of a spring-loaded snap-in ball  38  mechanism embedded in an end of the lever. This is used together with two separated holes  40  that mark the desired positions in the housing slot surface, to snap the lever easily into the engaged position or disengaged position. 
   Opening or unselecting a lever is achieved by simply pushing the exposed end of the short arm  43  of a lever inwards until the long arm  41  snaps into the position shown in  FIG. 2 . 
   In  FIGS. 2 and 3 , the housing  4  lineup holes  22  are shown including the alignment rods  14  that are through them. These cross-section figures also illustrate the importance of maintaining an accurate coincidence of the rotation axis for all the stacked rotatable components, hence the need for the use of the alignment rods  14 . 
   Referring now to  FIGS. 4 and 5 , there are shown respectively a plan view of a spring base  44  and cross-section view taken along line  5 — 5  of  FIG. 4 . The spring base  44  is disc-shaped and made of molded hard plastic, having semi-circular openings  39  in the peripheral edge that are regularly spaced apart all around the edge. These openings  39  in the gear tooth configuration, provide receptacles that are available for catching and retaining a hook portion  37  that projects from the side of a selector lever  16 . A generally circular shaped opening  46  is recessed in one side of the spring base for seating a circular-wound constant-force spring  28 , while a notched portion  47  in the opening wall  45  provides a means of securing the spring outer end. A circular axial hole  48  is provided to accommodate a rotatable hub  30 . 
     FIGS. 6 and 7  are respectively, an end view and side elevation view of a molded plastic hub  30  which has an outer diameter that is sized to fit the hub loosely in the spring base  44  axial hole  48 . The hub  30  includes an axial opening  52  that is sized and shaped to allow the hub to fit slidingly on a central shaft  32  that connects with a pulley  92  in the pulley assembly  8 . A radially inward spline  54  in the wall of the opening  52  fits into a longitudinal groove in the shaft  32 , locking the hub to the shaft, and a slit  50  provides securing means for an end of a flat-coiled spring. 
   It should be noted that the height of the hub  30  is made about a third greater than the height or thickness of the spring hub  44 . This is done so that when the spring assemblies  24  are stacked on the central shaft  32  inside their housing  4 , a rotating spring base surface can not rub against a stationary spring base  44  that may be above or below it, interfering with its free movement. 
     FIGS. 8 and 9  are respectively, a side view and a top, plan view of an external end cap  2 . Two through alignment holes  62  are provided in the cap top face  60  to each accommodate an end of an alignment rod  14 , and two through holes  64  are provided in opposite side ears to each hold the end of a clamping bolt  16 . A circular recess  66  is formed in the underside of the cap which fits against the end surfaces of a spring assembly housing  4  and holds an end of the central shaft  32 . The center of the recess  66  must be offset an amount “A” from the cap axis, so that when the end cap is lined up by alignment rods  14  through the housing  4 , the cap recess  66  center will coincide with the longitudinal axis of the shaft  32 . 
   Refer now to  FIGS. 10 ,  11 ,  12  and  13 .  FIGS. 10 and 11  are respectively, a side elevation view and an end view of a spring assembly housing  4 .  FIGS. 12 and 13  are respectively, a plan view and a side elevation view of a coupling end cap  6 . The coupling end cap  6  is made to fit on either end of the spring assembly housing  4  and is used to separate the housing  4  from an intermediate in-line assembly such as a pulley assembly  8 , which is shown in  FIG. 1 . 
   In  FIGS. 10 and 11 , a cylindrical cavity  26  is shown extending in a spring assembly housing  4  from one end to the other. The longitudinal axis of the cavity  26  is laterally offset an amount “A” to match the position of the shaft  32  axis as measured from the alignment holes  22 . A number of horizontal slots  72  are cut in the control face  33  of the housing, and extend inwards sufficiently to permit outside access to a selector lever  16  that will be mounted in each slot  72 . A hole  70  is cut through the walls of each slot for a pivot shaft  34  that will pass through each selector lever  16 , providing a pivoting means for each lever  16 . 
   As for each of the in-line components, two alignment holes  22  are cut through the spring assembly housing  4 , and alignment holes  76  are cut through the coupling end cap  6 , for stacking by the alignment rods  14 . 
   In the housing member  4 , two holes  40  are cut in the surface of each slot  72 , to mate with a spring-loaded snap connector that is on one end of each selector lever  16  in the slot. 
   In the coupling end cap  6 , a central through hole  74  is cut and sized to permit passage of the central shaft  32 . The center of the hole  74  is laterally offset an amount “A” to match the position of the shaft axis. As a means of holding one end of the pivot shaft mentioned earlier in the housing description, a recessed hole  78  is provided, located near a corner of the cap  6  in the appropriate position. This, however, may be deemed unnecessary and be omitted, depending on the pivot means used for the selector levers  16 . 
   The central shaft  32  is shown in a partial side view in  FIG. 14  and end view in  FIG. 14A . It is simply a straight metal rod with a deep groove  80  cut along its entire length. This groove  80  is sized to fit closely over the projecting spline of each part that will be placed over the shaft to be rotated by the shaft. 
   Finally,  FIG. 15  depicts a perspective view of a pulley wheel assembly  8  that is sized and shaped to fit in line with the spring assembly housings  4  as shown in  FIG. 1 . The pulley wheel assembly  8  comprises a molded plastic pulley housing  90  and a metal pulley wheel  92  that is wound with a pull cord  20 . 
     FIGS. 16 ,  17  and  18  are respectively, a top plan view, a side view as seen looking into a central recessed portion, and a bottom plan view of the pulley housing  90 . A semi-circular recessed portion  98  is formed in the top of the housing  90  and sized to fit a wound pulley  92 , with clearance for easy pulley rotation. The surface  102  of the recessed portion is flat and smooth for seating the pulley, so that no bearings are needed to assist pulley rotation. A circular axial hole  100  is provided for the central shaft  32  to enter and engage the pulley  92  which is placed in the housing recessed portion. Two holes  94  are provided in the pulley housing for the insertion of locating rods  14  when the assembly is stacked in line in the exerciser device. 
   It should be noted that the pulley wheel housing front side  96  which will be close to the device control face  33 , has been cut back so that a substantial portion of a seated pulley wheel  92  will extend out of the pulley wheel housing as seen in  FIG. 15 . This is done to allow as much angular variation and play of the pull cord with respect to the device as is possible, exerted by an exerciser user. 
   Referring once more to the invention embodiment shown in  FIG. 1 , it should be noted that there are a considerable number of variations that can be made to this device, without affecting its basic principals of construction or mode of operation. For example, the device cross-section need not be rectangular as depicted. Since the device itself does not rotate, the device stacked body may be curved in any desirable shape, so long as a linear internal column construction is maintained and direct access to the selector levers  16  is provided. This fact opens possible usage of the invention to hand held use by individuals ranging from children to elderly adults for exercising. 
   The number of spring assembly housings  4  in a device may be as low as one or even four or more. Two or more pulley assemblies may be incorporated. The size, ratings and quantity of spring assemblies contained in a device are all variable. Thus a large number of device configurations, having the same basic characteristics of the present invention can be envisioned for various applications. From the foregoing, it is clear that the use and versatility of the original pulling device are greatly enhanced by the present invention. 
   Most of the device parts are fabricated from hard, molded plastic. Metal components used are few, consisting of the central shaft, two clamping bolts, the constant-force springs the pulley wheel, and two alignment rods. With the exception of the central shaft, all the metal parts are standard and can be readily purchased. 
   As compared, with the earlier design pulling device, there are no expensive, machined parts required, and far fewer parts in the total assembly. The ease of device assembly is obvious from the foregoing description. Therefore, manufacture of the device in quantity, should result in a much lower cost per invention device as compared with the earlier pulling exerciser device, and will be welcomed by potential users. 
   From the foregoing description, it is believed that the described preferred embodiment achieves the objects of the present invention. Alternative embodiments and modifications will be apparent to those skilled in the art. These and other modifications are considered to be equivalent and within the spirit and scope of the present invention.