Patent Publication Number: US-11027183-B2

Title: Wall climbing structure

Description:
CROSS REFERENCE TO RELATED APPLICATION 
     The present application is a non-provisional application of U.S. Provisional Patent Application No. 62/801,215, filed on Feb. 5, 2019, entitled “Wall Climbing Structure”. The entire contents of U.S. Provisional Patent Application No. 62/801,215 are herein incorporated by reference. 
    
    
     The section headings used herein are for organizational purposes only and should not to be construed as limiting the subject matter described in the present application in any way. 
     INTRODUCTION 
     The popularity of rock climbing has created a market for artificial climbing walls and other climbing structures. Climbing walls with continuous sliding belts have been recently developed to accommodate climbers with limited space. These climbing walls are popular in various gym environments. Such climbing walls provide a continuous climbing surface for recreation, training, rehabilitation, and fitness purposes in a modest foot print that can easily fit into a gym. Some known climbing walls with continuously sliding belts are powered by electric motors. Other climbing walls, such as the climbing walls manufactured by Brewers Ledge Inc., the assignee of the present application, use the climber&#39;s own weight to power sliding belts. 
     Currently, there is a need in the fitness industry for climbing structures that are more compact, simpler to install, and simpler to use. In addition, there is currently a need in the fitness industry for climbing structures that can be more easily configured and that have easy to operation user controls that change the climbing angle of the wall. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The present teaching, in accordance with preferred and exemplary embodiments, together with further advantages thereof, is more particularly described in the following detailed description, taken in conjunction with the accompanying drawings. The skilled person in the art will understand that the drawings, described below, are for illustration purposes only. The drawings are not necessarily to scale, emphasis instead generally being placed upon illustrating principles of the teaching. The drawings are not intended to limit the scope of the Applicant&#39;s teaching in any way. 
         FIG. 1A  illustrates an embodiment of a climbing structure of the present teaching set at a 10-degree slab position. 
         FIG. 1B  illustrates an embodiment of the climbing structure described in connection with  FIG. 1A  set at a −35-degree overhang position. 
         FIG. 1C  illustrates a rear-view of the embodiment of the climbing structure of  FIG. 1B . 
         FIG. 2A  illustrates a side-view of an embodiment of an A-frame supporting a steep-angle with a ten-foot height of the present teaching. 
         FIG. 2B  illustrates a side-view of an embodiment of an A-frame supporting a steep-angle with an eleven-foot height of the present teaching. 
         FIG. 2C  illustrates a side-view of an embodiment of an A-frame supporting a steep-angle with a twelve-foot height of the present teaching. 
         FIG. 3A  illustrates a side-view of an embodiment of an A-frame supporting a regular-angle with a ten-foot height of the present teaching. 
         FIG. 3B  illustrates a side view of embodiment of an A-frame supporting a regular-angle with an eleven-foot height of the present teaching. 
         FIG. 3C  illustrates a side-view of embodiment of an A-frame supporting a regular-angle with a twelve-foot height of the present teaching. 
         FIG. 4A  illustrates a perspective view of an embodiment of a lower shaft assembly of the present teaching. 
         FIG. 4B  illustrates another perspective-view of the embodiment of a lower shaft assembly of  FIG. 4A . 
         FIG. 4C  illustrates a detailed perspective-view of the left end of the embodiment of a lower shaft assembly of  FIG. 4A . 
         FIG. 4D  illustrates another detailed perspective-view of the left end of the embodiment of a lower shaft assembly of  FIG. 4A . 
         FIG. 4E  illustrates a detailed perspective-view of the right end of the embodiment of a lower shaft assembly of  FIG. 4A . 
         FIG. 4F  illustrates another detailed perspective-view of the right end of the embodiment of a lower shaft assembly of  FIG. 4A . 
         FIG. 5  illustrates a partial-view of an embodiment of a right channel of a portion of the wall assembly attached to a shaft assembly of the present teaching. 
         FIG. 6A  illustrates an embodiment of a cable hub assembly without cable of the present teaching. 
         FIG. 6B  illustrates an embodiment of a cable hub assembly of  FIG. 6A  with cable. 
         FIG. 6C  illustrates an exploded view of the embodiment of the cable hub assembly of  FIG. 6A . 
         FIG. 7A  illustrates a perspective-view of an embodiment of a soft-lever control mechanism of the present teaching. 
         FIG. 7B  illustrates another perspective-view of the soft-lever control mechanism of  FIG. 7A . 
         FIG. 7C  illustrates a third perspective-view of the soft-lever control mechanism of  FIG. 7A . 
         FIG. 8A  illustrates a perspective-view of another embodiment of a soft-lever control mechanism of the present teaching. 
         FIG. 8B  illustrates another perspective-view of the inside of the soft-lever control mechanism embodiment of  FIG. 8A . 
     
    
    
     DESCRIPTION OF VARIOUS EMBODIMENTS 
     Reference in the specification to “one embodiment” or “an embodiment” means that a particular feature, structure, or characteristic described in connection with the embodiment is included in at least one embodiment of the teaching. The appearances of the phrase “in one embodiment” in various places in the specification are not necessarily all referring to the same embodiment. 
     It should be understood that the individual steps of the methods of the present teachings may be performed in any order and/or simultaneously as long as the teaching remains operable. Furthermore, it should be understood that the apparatus and methods of the present teachings can include any number or all of the described embodiments as long as the teaching remains operable. 
     The present teaching will now be described in more detail with reference to exemplary embodiments thereof as shown in the accompanying drawings. While the present teachings are described in conjunction with various embodiments and examples, it is not intended that the present teachings be limited to such embodiments. On the contrary, the present teachings encompass various alternatives, modifications and equivalents, as will be appreciated by those of skill in the art. Those of ordinary skill in the art having access to the teaching herein will recognize additional implementations, modifications, and embodiments, as well as other fields of use, which are within the scope of the present disclosure as described herein. 
     The present teaching relates to a climbing structure that include a series of climbing panels that are attached to two loops of roller chain at the left and right ends. Top and bottom shaft assemblies are attached to sprockets at the left and right edges. These top and bottom shaft assemblies maintain tension of the left and right loops of roller chain that guide the panels as they travel around the wall. The climbing panels are also guided into a vertical loop with flat surfaces at the front and back by sheet-metal channels. 
     Known versions of such climbing structures use arrays of climbing panels guided into a vertical loop by sheet metal channels that are mounted at the upper end with bearings on the same shaft that carries the upper sprockets holding the panel array. In these known climbing structures, the entire wall assembly is supported by a large A-frame support frame with bearings at the top to support the upper shaft. The bottom end of the panel array also has a shaft with sprockets that engage the left and right loops of chain and that maintains alignment of the panels as they circulate around the bottom end. The flat series of panels at the front of this array are equipped with climbing holds. The wall rotates under the weight of the climber. To regulate the speed of the wall, a separate sprocket is fitted to the upper shaft, and a hydraulic braking mechanism provides adjustable drag to the rotation. A separate means of cutting off all flow of oil in the hydraulic system provides a way of stopping the wall when the climber is resting near the bottom of the array. See, for example, U.S. Pat. No. 9,440,132, entitled “Rung Wall Ascender” and U.S. Pat. No. 7,572,208, entitled “Climbing Wall with Braking Mechanism”, both of which are assigned to the present assignee. 
     Importantly, in these known structures, the wall orientation is changed from a “slab” orientation to an overhanging angle orientation using a third shaft, which is positioned at the middle of the array. The slab orientation refers to orientations that have small positive angles with respect to the vertical direction. The third shaft on these known structures is fitted with bearings through the center of the two side channels and extends beyond the A-frames. The third shaft does not contact the panels themselves. Cables on each side of the machine are wrapped around this shaft and attached at the front and rear legs of the A-frame. A wheel at one end of third shaft allows the user to adjust the angle by winching the wall forward and back and locking it in place with a simple disk and pin lock. Without the cables in place, the two channels are basically free to swing independently forward and back, since there is very little structure between the two channels. The cables provide the necessary force to maintain alignment of the two channels. 
     Some known climbing structures use a half-height frame where the wall assembly is mounted by bearings near its center-of-gravity. This configuration eliminates the sheet metal channels and cables. The balance of the wall assembly is arranged so that, without a climber positioned on the structure, the climbing structure naturally tilts forward into the slab position and, with the climber on the climbing structure, the climbing structure tilts back into the overhanging position. A hydraulic cylinder locks the angle and allows the climber to adjust the wall to a steeper angle without dismounting. 
     Other known climbing structures have a vertical-only position that has a minimum footprint and that is rigidly mounted in a vertical frame. Still other known climbing structures are configured in a steep angle, with a channel pivoting from the bottom, and the substantial weight of the overhanging wall is supported by a sturdy, but somewhat clumsy set of jacks and uprights. 
     There are numerous drawbacks to these known climbing structures. For example, the large A-frame is rather ungainly and takes up a considerable floor space. Furthermore, the range of angle is limited by the A-frame size and shape. The range of angles is also limited by practical constraints on the angle adjustment cables as the winching-forces in this configuration are relatively high at steeper angles. For example, known cable-based systems are generally limited to about a 12-degree overhang, which is not appropriate for serious climber training. In addition, the overhang angle can only be changed by dismounting or with the aid of a second non-climbing person. These known systems can be cumbersome to adjust and lack the desired flexibility to provide for a large range of climber ability that is typical of users in climbing gyms. 
     The present teaching addresses shortcomings of known climbing structures. One aspect of the present teaching is to provide a climbing structure with a full range of wall angle adjustment, from beginner level to expert level, with an easy-to-use and convenient interface that does not require dismounting the climber. Various embodiments of the climbing structures of the present teaching include a range of configurations with different footprints and a different range of wall angle adjustments. Also, the wall angle adjustment is robust, relatively trouble-free and economical to make. This is, at least in part, due to the elimination of the hydraulic cylinder that is present in known systems. Also, various embodiments of the climbing structure of the present teaching minimize use of heavy and expensive reinforcing materials. 
     The climbing structure of the present teaching allows the user to configure the structure by selecting options that suit their own particular situation. That is, the climbing structure can be configured for different ceiling heights, floor spaces, ability levels, etc. For example, some embodiments are configured to provide a full +10 degree to −35 degree range of wall angle adjustment and other embodiments can are configured to provide as little as +10 to −15 degree range of wall angle adjustment. Still other embodiments are configured to provide a +10 to −20 degree range of wall angle range. 
     More specifically, the present teaching relates to climbing structures that include a series of climbing panels that are, for example, six inches tall and less than or equal to six feet wide or less than or equal to four feet wide. The climbing panels are attached to two loops of roller chain at the left and right ends. Top and bottom shaft assemblies are attached to sprockets at the left and right edges. These top and bottom shaft assemblies maintain tension of the left and right loops of roller chain and guide the panels as they travel around the wall. The climbing panels are guided into a vertical loop with flat surfaces at the front and back by sheet-metal channels. Various embodiments of the climbing structures can range in height, but some specific embodiments are in the ten to twelve foot range. 
       FIG. 1A  illustrates an embodiment of a climbing structure  100  of the present teaching set at a 10-degree slab position. The climbing structure  100  includes a wall assembly  102  having channels  104 ,  106  on both sides that enclose a chain drive system (not shown). The rigidity and alignment of the channels  104 ,  106  are important characteristics for proper operation of the climbing structure  100 . 
     An array of panels  108  is positioned on the climbing surface of the wall assembly  102 . For example, each panel in the array of panels  108  can be six inches tall and four or six feet wide. Also, each panel in the array of panels  108  has a number of holes configured to attach a variety of different climbing holds. The array of panels  108  follow a path back upward along the back side of the wall assembly  102  along a vertical loop with flat surfaces at the front and back. 
     A top cover  110  is positioned across and attached to each channel  104 ,  106  so as to cover the upper curve of the panel array trajectory. The top cover  110  prevents a climber&#39;s fingers from getting pinched between panels  108  as they rotate over the upper curve. A conveniently located brake handle  112  is positioned near the mid-point of the climbing structure  100  so that the climber can reach it during climbing in most positions. 
     One feature of the present teaching is the selection of the wall pivot point on the frame that includes two A-frame support frames  114 ,  116 . While pivoting the wall from the base produces the smallest footprint, this position has the disadvantage that it produces relatively high major support forces, especially in the overhanging positions. Various means of dealing with these forces are inadequate without the use of motorized or other powered options. Pivoting the wall from the top creates similar problems and also requires an ungainly footprint. As such, and referring also to  FIG. 1B , the climbing structure  100  uses a pivot point  118  that is at the center of the wall assembly  102  in the vertical direction. The two A-frame support frames  114 ,  116  are positioned to the right and left of the wall assembly  102  as shown in  FIGS. 1A and 1B . The A-frames  114 ,  116  attach to the wall assembly  102  at the pivot point  118 . The pivot point  118  is positioned on the channel  104  at a particular point that in some configurations that is slightly behind the center of gravity of the wall assembly  102  in the horizontal dimension, and nominally at the center of gravity of the wall assembly  102  in the vertical dimension, which is nominally at the center of the wall assembly  102  from top to bottom. This position of the pivot point  118  is chosen to allow the wall assembly to settle to a slab position when no climber is on the wall. This position of the pivot point  118  ideally allows for climber&#39;s body weight to shift the center of gravity of the wall assembly  102  to a point somewhat in front of the pivot point  118 . With this shift in position of the center of gravity, the wall assembly  102  will tend to settle to an overhanging position. This allows the climber&#39;s body weight alone to adjust the angle. For example, in operation, the angle of the wall assembly  102  can be adjusted to any point from a 10-degree slab position to a −35 degree overhang position based on a position and a weight of a climber on the wall assembly  102 . 
     Also, the position of the center of gravity of the wall assembly  102  used to determine the pivot point  118  is determined based on a wall assembly with no climbing holds. However, in operation, the center of gravity of the wall assembly  102  populated with various arrangements and number of climbing holds is nominally the same because they tend to be equally distributed around the panel array. Climbing structures according to the present teaching use a pivot point  118  in which the wall assembly  102  is supported from a position close to its center of gravity (COG). The number of holds used at various install locations varies considerably and some users put on as many as 140 holds weighing as much as 3 pounds each. Even if the holds are evenly distributed, the additional weight alters the position of the COG unless it is near the center of the wall height. The center of gravity can be adjusted by using counterweights so that the pivot point is in the desired location. 
     A brake mechanism (not shown) which is actuated by the brake handle  112  is used to fix the angle of the wall assembly  102  at a desired angle. 
     In an example of operation, a climber mounts the wall with the brake on and the wall at the nominally 10-degree slab position that occurs when no climber is on the wall. With the particular pivot point  118 , the body weight of the climber is sufficient to move the wall the full range of wall angle when the brake is released. The climber fixes the desired wall angle by engaging the braking mechanism. 
     The bottom  120  of the wall assembly  102  is connected to the A-frames  114 ,  116  via a shaft assembly (not shown) described below. A panel  122  may be optionally fixed to one or both of the A-frames  114 ,  116 . The panel  122  prevents interference with the wall assembly  102  motion. 
     In operation, as the climber ascends the wall assembly, the panels move downward in response to the forces of the climbing action. This downward rotation as the climber climbs provides a continuous climbing experience. 
       FIG. 1B  illustrates the embodiment of the climbing structure  100  described in connection with  FIG. 1A  set at a −35-degree overhang position.  FIG. 1B  illustrates the angle as set by rotation of the wall assembly  102  around the pivot point  118 . Referring to both  FIGS. 1A and 1B , at the two extremes of the angle of the wall assembly  102 , the bottom  120  of the wall assembly  102  does not extend substantially beyond the front or back of the base of the A-frames  116 ,  114 . 
       FIG. 1C  illustrates a rear-view of the embodiment of the climbing structure  100  set at a −35-degree overhang position. This rear-view clearly illustrates the two cross bars  124 ,  126  and two turnbuckle systems with braces  128 ,  130  that are used to attach the two A-frames  114 ,  116 . On the wall assembly  102 , a back shroud  140  is mounted to the right and left side channels  104 ,  106 . The shroud  140  has three counter weights  142  which maintain the center of gravity of the wall assembly  102  at a location near the middle of the channels  104 ,  106 . Pivot point  118 , which is set slightly behind the center of gravity of the wall assembly  102  in the horizontal dimension, and nominally at the center of gravity of the wall assembly  102  in the vertical dimension, is shown on the A-frame  116 . 
     One feature of the present teaching is that it is compatible with multiple desired climbing structure sizes and wall angle ranges. As described herein, in connection with the description of  FIGS. 2A-C  and  3 A-C, in various embodiments, the A-frames are of two types of three sizes each. The upper sections of each frame are similar so that the only difference in the legs is their lengths. In this way a single welding jig can be used for all sizes. 
       FIG. 2A  illustrates a side-view of an embodiment of an A-frame  200  supporting a steep-angle with a ten-foot height of the present teaching. This embodiment of A-frame  200  is capable of supporting a wall angle from +10 to −35 degrees from vertical. A-frame  200  includes a front support leg  202 , and a rear support leg with an upper section  204  and a lower section  206 . A bottom cross bar  208  connects the front support leg  202  to the lower section  206  and a middle cross bar  210  connects the front support leg  202  to the upper section  204 . The middle cross bar  210  forms an angle with the horizontal to support a wall angle from +10 to −35 degrees from vertical. An upper cross bar  214  connects the front support leg  202  to the upper section  204 . The upper cross bar  214  includes a short shaft  212  that is positioned to connect a wall assembly. 
     The A-frame  200  has a height, H  216 , of five feet. The front support leg  202  has a particular radius of curvature, R  218 . This curved shape and associated radius, R, of the front support leg  202  beneficially positions the bottom of the front support leg at a sufficient distance, B  220 , between the front support leg  202  and the lower section  206  to maintain stability of the climbing structure and minimizes interference with the climber and/or climbing functions because it curves away from the front of the climbing structure. The curve also provides a distinctive feature for branding and softens the look and feel of the climbing structure. 
       FIG. 2B  illustrates a side-view of an embodiment of an A-frame  230  supporting a steep-angle with an eleven-foot height of the present teaching. This embodiment of A-frame  230  has similar elements and features as the embodiment described in connection with  FIG. 2A . There is front support leg  232 , a rear support leg with an upper section  234 , a lower section  236 , a lower cross bar  238 , a middle cross bar  240 , and an upper cross bar  242  with a short shaft  244  to connect a wall assembly. This embodiment of A-frame  230  has a height, H  246 , of 5½ feet. The front support leg  232  has a particular radius of curvature, R  248 , which positions the bottom of the front support leg  232  at a sufficient distance, B  250 , to the lower section  236  to ensure stability of the climbing structure. This embodiment of A-frame  230  is capable of supporting a wall angle from +10 to −35 degrees from vertical. 
       FIG. 2C  illustrates a side-view of an embodiment of an A-frame  260  supporting a steep-angle with a twelve-foot height of the present teaching. This embodiment of A-frame  260  has similar elements as the embodiments described in connection with  FIGS. 2A and 2B . There is front support leg  262 , a rear support leg with an upper section  264 , a lower section  266 , a lower cross bar  268 , a middle cross bar  270 , and an upper cross bar  272  with a short shaft  274  to connect a wall assembly. 
     This embodiment of the A-frame  260  has a height, H  276 , of six feet. The front support leg  262  has a particular radius of curvature, R  278  that positions the bottom of the front support leg  262  at a sufficient distance, B  280 , from the lower section  266  to ensure stability of the climbing structure. This embodiment of A-frame  260  is capable of supporting a wall angle from +10 to −35 degrees from vertical. The wall angle ranges for various embodiments of the climbing structure elements described herein are only examples of the present teaching and are not limiting in any way. A variety of wall angle ranges can be provided as will be understood by those skilled in the art. 
       FIG. 3A  illustrates a side-view of embodiment of an A-frame  300  supporting a regular-angle with a ten-foot height of the present teaching. This embodiment of A-frame  300  is capable of supporting a wall angle from +10 to −20 degrees from vertical. The A-frame  300  includes a front support leg  302 , and a rear support leg  304 . A bottom cross bar  306  and a middle cross bar  308  connect the front support leg  302  to the rear support leg  304 . The middle cross bar  308  also connects to a wall assembly (not shown). The middle cross bar  308  forms an angle with the horizontal to support a wall angle from +10 to −20 degrees from vertical. An upper cross bar  310  connects the front support leg  302  to the rear support leg  304 . The upper cross bar  310  includes a short shaft  312  that is positioned to connect a wall assembly. The A-frame  300  has a height, H  314 , of five feet. The front support leg  302  has a particular radius of curvature, R  316 . This curved shape and associated radius, R  316 , of the front support leg  302  beneficially positions the bottom of the front support leg  302  at a sufficient distance, B  318 , between the front support leg  302  and the rear support leg  304  to maintain stability of the climbing structure and minimizes interference with the climber and/or climbing functions because it curves away from the front of the climbing structure. The curve also provides a distinctive feature for branding and softens the look and feel of the climbing structure. 
       FIG. 3B  illustrates a side-view of embodiment of an A-frame supporting a regular-angle with an eleven-foot height of the present teaching. This embodiment of A-frame  330  has similar elements and features as the embodiment described in connection with  FIG. 3A . There is front support leg  332 , and a rear support leg  334 , a lower cross bar  336 , a middle cross bar  338 , and an upper cross bar  340  with a short shaft  342  to connect a wall assembly. This embodiment of A-frame  330  has a height, H  344 , of 5½ feet. The front support leg  332  has a particular radius of curvature, R  346 , that positions the bottom of the front support leg  332  at a sufficient distance, B  348 , to the rear support leg  334  to ensure stability of the climbing structure. This embodiment of A-frame  330  is capable of supporting a wall angle from +10 to −20 degrees from vertical. 
       FIG. 3C  illustrates a side-view of embodiment of an A-frame supporting a regular-angle with a twelve-foot height of the present teaching. This embodiment of A-frame  360  has similar elements and features as the embodiment described in connection with  FIG. 3A . There is front support leg  362 , and a rear support leg  364 , a lower cross bar  366 , a middle cross bar  368 , and an upper cross bar  370  with a short shaft  372  to connect a wall assembly. This embodiment of A-frame  360  has a height, H  374 , of six feet. The front support leg  362  has a particular radius of curvature, R  376 , that positions the bottom of the front support leg  362  at a sufficient distance, B  378 , to the rear support leg  364  to ensure stability of the climbing structure. This embodiment of A-frame  330  is capable of supporting a wall angle from +10 to −20 degrees from vertical. 
     One aspect of the present teaching is realization that the lower sprocket shaft can be used for more than a chain-tensioning device.  FIG. 4A  illustrates a perspective-view of an embodiment of a lower shaft assembly  400  of the present teaching.  FIG. 4B  illustrates another perspective view of the embodiment of a lower shaft assembly  400  of  FIG. 4A . One feature of the present teaching is that the lower shaft assembly  400  allows for three important functions. Referring to  FIGS. 1A and 4A -B, the lower shaft assembly  400  maintains tension on the chains (not shown) that are housed in channels  104 ,  106 . The lower shaft assembly  400  controls the wall angle of the wall assembly  102 . The lower shaft assembly  400  also maintains alignment of the channels  104 ,  106 . 
     The shaft assembly  400  includes the bottom shaft  402  with cable hub assemblies  404 ,  406  attached to the ends of the shaft  402 . These cable hub assemblies  404 ,  406  can be configured to clamp the cables  403 ,  405  rather than to have the cables  403 ,  405  pass internally so as to make the cables  403 ,  405  easily replaceable in case of damage or to perform maintenance. As described in connection with  FIG. 5 , the cables  403 ,  405  are spring loaded at the rear end and are attached to the front and rear legs of respective A-frames  114 ,  116  and maintain the two channels  104 ,  106  in excellent and solid alignment at all wall angles. The cable hub assemblies  404 ,  406  and cables  403 ,  405  are used to guide the movement of the wall assembly  102  through various wall angles. The two cable hub assemblies  404 ,  406  rotate the shaft  402  as the wall angle changes. 
     Two sprockets  408 ,  410  are positioned at either end of a shaft  402 . In some configurations, the sprockets  408 ,  410  are not keyed to the shaft  402 . Instead, the sprockets  408 ,  410  are on bearings that rotate freely. This results in the shaft  402  at the bottom of the wall that rotates independently from the sprockets  408 ,  410 . One advantage the shaft  402  rotating independently is that the shaft  402  can then be used with a cable arrangement to align the channels and to provide an angle-locking means. The sprockets  408 ,  410  are driven by two chains (not shown) in the channels  104 ,  106 . The chains guide the movement of the array of panels  108 . 
     With the cable arrangement in place, there are a couple of ways to lock the wall angle. One means to lock the wall angle is to use a dampening cylinder with a locking mechanism. Dampening of the wall angle change is necessary to control the speed of the angle change, but cylinders that lock in this way are not common and, therefore are expensive. Known cylinders also have questionable durability in a fitness environment. Another means for locking the wall angle is to control the rotation of the lower shaft with a braking system. This can be accomplished with the use of a disk brake. There are many types of suitable disk brakes. One relatively inexpensive type of disk brake that is suitable for this application in size and braking capability is a bicycle-type caliper brake. This type of brake is controlled by a cable-lever system that the climber can easily control. 
     A disc brake mechanism  412  is used to fix the wall assembly  102  at a particular wall angle. The shaft assembly  400  is attached at one end to the channel  104  using a bearing  415  and a plate  414  and at the other end to the channel  106  using a bearing  425  and plate  426 . Plates  414  and  426  are equipped with a slot  416  which allows bearings  415 ,  425  to pivot to allow for the relative motion between the wall assembly  102  and the shaft as the wall is in operation and to allow tension adjustment of the chains (not shown). The disc brake system  412  when activated will halt the rotation of the shaft  402  to hold the wall angle at all points in the wall angle range. 
       FIG. 4C  illustrates a detailed perspective view of the left end of the embodiment of a lower shaft assembly  400  of  FIG. 4A .  FIG. 4D  illustrates another detailed perspective view of the left end of the embodiment of a lower shaft assembly  400  of  FIG. 4A . The disc brake system  412  includes a disc  420 , attached to the shaft  402 , a caliper mounting plate  421  and a caliper  422  that applies pressure to the disc  420  to stop rotation of the shaft  402 . Releasing the caliper  422  allows rotation of the shaft  402 . The disc brake system  412  is designed to work at all wall angles. The disc  420  is rigidly attached to the shaft, and the caliper mounting plate  421  is mounted on the bolts that hold bearing  425  so the caliper  422  can float along with the shaft  402  with respect to the wall channels  104 ,  106 . The sprocket  410  is free to rotate around the shaft  402 . The cable hub assembly  406  is rigidly attached to the shaft  402 . A bearing lever  424  is spring loaded so that tension is maintained on a chain (not shown) engaged by the sprocket  410  when the shaft assembly  400  is attached to the wall channels  104 ,  106 . 
     One feature of the present teaching is that it is easy to assemble on site.  FIG. 4E  illustrates a detailed perspective view of the right end of the embodiment of a lower shaft assembly  400  of  FIG. 4A .  FIG. 4F  illustrates another detailed perspective view of the right end of the embodiment of a lower shaft assembly  400  of  FIG. 4A . Sprocket  408  is free to rotate around the shaft  402 . The cable hub assembly  404  is rigidly attached to the shaft  402 . The shaft assembly attaches to the wall assembly via simple bolting of the mounting plate  414 . Mounting plate  414  is secured to the channels  104 ,  106 . A bearing lever  424  is spring loaded so that tension is maintained on a chain (not shown) engaged by the sprocket  408  when the shaft assembly  400  is attached to the wall channels  104 ,  106 . The attachment for the other side is configured similarly. The shaft assembly  400  is attached to the A-frames  114 ,  116 . 
       FIG. 5  illustrates a partial view of an embodiment of a right channel of a portion  500  of the wall assembly attached to a shaft assembly of the present teaching. The right channel guide  104  contains the chain (not shown) that guides wall panels  108  as they rotate around the wall assembly  102 . Mounting plate  414  attaches to the guide  104 . The bearing lever  424  is attached to a back guard  502 . A bearing tension lever spring attaches between the lever  426  and the top of the back guard  502  to maintain chain tension. Cable hub assembly  404  attaches via a back section  504  of cable  403  and a spring  506  to a rear leg of the A-frame  114  (not shown). The wall assembly left channel portion (not shown) is similarly configured to the right channel portion  500  shown in  FIG. 5 . 
       FIG. 6A  illustrates an embodiment of a cable hub assembly  600  without cable of the present teaching. Two outer flanges  602 ,  604  are positioned on either side of two hubs  606 ,  608 , that are positioned on either side of a center disk  610 . The center disk  610  has a cut-out  612 .  FIG. 6B  illustrates an embodiment of a cable hub assembly  600  with cable  620  of  FIG. 6A . A cable  620  is slipped into the slot formed by the cut-out  612  on the center disk  610  during assembly and held into place by the hubs  606 ,  608 . Each hub  606 ,  608  is angled from the outer flanges  604 ,  606  toward the center disk  610  at a shallow 3-degree angle to keep the cable winding properly aligned as the cable  620  winds and unwinds from the cable hub  600  during operation. The 3-degree taper guides the cable  620  toward the center of the cable hub assembly  600 .  FIG. 6C  illustrates an exploded view of the embodiment of the cable hub assembly  600  of  FIG. 6A . In addition to outer flanges  602 ,  604 , hubs  606 ,  608  and disk  610  with cut-out  612 , the threaded inserts  642  and screws  640  that hold the cable hub assembly  600  together are shown. A locking collar  644  is used to secure the hub to the shaft. 
     As described herein, one feature of the present teaching is that the wall angle can be controlled by the climber during operation. Body weight of a climber is sufficient to change the wall angle and a braking mechanism is controlled by the climber to set the wall at the desired angle.  FIG. 7A  illustrates a perspective view of a soft-lever control mechanism  700  of the present teaching. Referring to  FIGS. 1A and 7A , the soft-lever mechanism  700  attaches to the wall assembly  102  channel  106  using attachment holes  702 . This positioning makes brake handle  112  easy to reach by a climber that is on the wall assembly in operation.  FIG. 7B  illustrates another perspective view of a soft-lever control mechanism  700  of  FIG. 7A . Brake handle  112  is attached to a bottom plate  704  that serves as an adjustment lever. A top plate  706  that serves as a caliper control lever, is attached to the bottom plate  704  at pivot bolt  708 . The top plate  706  and bottom plate  708  pivot independently on the pivot bolt  708 . The two plates  704 ,  706  are coupled to each other through the torsion spring ( FIG. 7C ). The cable  710  connects to the caliper (not shown). A screw  712  locks the cable and facilitates adjustment. The main spring  714  actuates the angle locking caliper. A lug  716  presses against the top plate  706  to fully release the caliper at the end of the stroke of the bottom plate  704  (adjustment lever).  FIG. 7C  illustrates a third perspective view of the soft-lever control mechanism  700  of  FIG. 7A .  FIG. 7C  illustrates the torsion spring  718  that links the top plate  706  to bottom plate  704 . 
     Referring to  FIGS. 7A-C , in the rest position, the main spring  714  pulls down on the caliper control lever, top plate  706 . This locks the angle of the wall in place. As the adjustment lever, bottom plate  704  is moved down, the torsion spring  718  between the two plates  704 ,  706  gradually increases force against the top plate  706 . This counters the force that the main spring  714  exerts against the cable  710 . This causes the caliper to release slowly, rather than a sudden release. At the bottom of the stroke, the lug  716  on the bottom plate  704  presses against the top plate  706  (caliper control lever), forcing the lever up (top plate  706 ) to ensure the full release of the caliper. This design of the soft-lever control mechanism  700  advantageously prevents abrupt action from the braking control mechanism. This is sometimes referred to as “soft-release” braking. 
       FIG. 8A  illustrates a perspective-view of another embodiment of a soft-lever control mechanism  800  of the present teaching. The soft-lever control mechanism  800  is mounted on a channel  106 . A brake handle  112  is used by the climber to actuate the braking mechanism and set the desired wall angle. The brake handle  112  is attached to a lever assembly  802 . The lever assembly  802  has pulley-like disks for accepting a cable  804 . The cable  804  is looped around the lever assembly  802  and fed through a cable stop  806 . One end of the cable  804  exits the channel through the slot  808 . The cable  804  is enclosed in a cover after the cable stop  806 . The other end of the cable  804  is attached to one end of a balance spring  810 . The other end of the balance spring  810  is secured to the channel  106 . The balance spring  810  acts to return the lever assembly  800  to a neutral position. When the brake handle  112  is at the upper most position (as shown) the soft-lever control mechanism  800  is in a neutral position. In the neutral position the brake is applied and the wall remains at the angle. Moving the brake handle  112  downward releases tension of the cable on the caliper (not shown). This allows the wall to move along the wall angle range. Releasing the handle  112  causes the brake to set, and the wall angle to be held at a desired angle. 
       FIG. 8B  illustrates another perspective-view of the inside of the soft-lever control mechanism  800  of  FIG. 8A . Referring to both  FIGS. 8A-B , the covered cable  804  comes through to the other side of the channel  106  at the slot  808 . The cable  804  passes through a second cable stop  812 . This section of the cable  804  is covered. The bare cable  804  then passes to an attachment to a main spring  814 . The main spring  814  tensions the cable to lock the caliper (not shown). The main spring  814  is weaker than the balance spring  810 . Moving the brake handle  112  down releases the tension on the main spring  814 . Another bare cable  816  is attached to the other side of the main spring  814 . This bare cable  816  passes through a third cable stop  818 . The cable  816  exits the cable stop  818  and connects to the caliper (not shown) through a cover. 
     EQUIVALENTS 
     While the applicants&#39; teaching is described in conjunction with various embodiments, it is not intended that the applicants&#39; teaching be limited to such embodiments. On the contrary, the applicants&#39; teaching encompass various alternatives, modifications, and equivalents, as will be appreciated by those of skill in the art, which may be made therein without departing from the spirit and scope of the teaching.