Patent Publication Number: US-8974334-B2

Title: Cable drive and tension assembly

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     This Application claims priority to U.S. Provisional Application Ser. No. 61/547,284, same title herewith, filed on Oct. 14, 2011, which is incorporated in its entirety herein by reference. 
    
    
     BACKGROUND 
     The ability to service devices that are elevated requires a system for getting a service technician to the device. One common system used to reach elevated locations is a ladder. However, when the distance to reach the device is significant, the use of a ladder is restricted to only those individuals that are physically capable of climbing the distance of the ladder. Safety issues also have to be considered. The more fatigue a worker is experiencing, the more likely an accident could occur, such as slipping and falling. Hence, fatigue that comes with climbing great distances should be taken into consideration when implementing a system to reach a device at an elevated location. A climb assist system can be used to aid the worker in climbing the ladder. A typical climb assist system would employ a motor driven looped cable that is attached to a safety harness donned by the worker. 
     For the reasons stated above and for other reasons stated below which will become apparent to those skilled in the art upon reading and understanding the present specification, there is a need in the art for an efficient and effective method of tensioning an endless looped member in a climb assist system to ensure the proper operation of the climb assist system. 
     SUMMARY OF INVENTION 
     The above-mentioned problems of current systems are addressed by embodiments of the present invention and will be understood by reading and studying the following specification. The following summary is made by way of example and not by way of limitation. It is merely provided to aid the reader in understanding some of the aspects of the invention. 
     In one embodiment, a tensioning assembly is provided. The tensioning assembly includes a drive pulley, a tension pulley and a tension adjustment system. The drive pulley has a first drive pulley channel and a second drive pulley channel. The tension pulley has a first tension pulley channel and a second tension pulley channel. The second tension pulley channel is aligned with the first drive pulley channel. The first drive pulley channel and the second drive pulley channel of the drive pulley and the first tension pulley channel and a second tension pulley channel of the tension pulley are configured and arranged to engage and route an endless looped member. The tension adjustment system is coupled to adjust the distance between the drive pulley and the tension pulley to adjust the tension in the endless looped member in relation to the drive pulley. 
     In another embodiment, a drive and tensioning assembly is provided. The assembly includes a housing, a drive pulley, a drive assembly, a tension pulley and a tension adjustment system. The drive pulley is received in the housing and has a first drive pulley channel and a second drive pulley channel. The drive assembly includes a drive shaft. The drive assembly is configured to rotate the drive shaft. The drive shaft extends through a housing aperture. Moreover, the drive pulley is in rotational communication with the drive shaft of the drive assembly. The tension pulley is also received in the housing and has a first tension pulley channel and a second tension pulley channel. The second tension pulley channel being aligned with the first drive pulley channel. The first drive pulley channel and the second drive pulley channel of the drive pulley and the first tension pulley channel and a second tension pulley channel of the tension pulley configured and arranged to engage and route an endless looped member into and out of the housing. The tension adjustment system is coupled to adjust the distance between the drive pulley and the tension pulley in the housing. 
     In still another embodiment, a climb assist system is provided. The climb assist system includes an upper pulley assembly, a lower pulley assembly, a tension assembly and a drive assembly. The upper pulley assembly is configured and arranged to be coupled to an upper rung of a ladder. The upper pulley assembly is further configured to route an endless looped member about different sides of the ladder. The lower pulley assembly is configured and arranged to be coupled to an lower rung of a ladder. The lower pulley assembly is further configured to route the endless looped member about different sides of the ladder to the upper pulley assembly. The tension assembly includes a drive pulley, a tension pulley and a tension adjustment system. The drive pulley has a first drive pulley channel and a second drive pulley channel. The tension pulley has a first tension pulley channel and a second tension pulley channel. The second tension pulley channel is aligned with the first drive pulley channel. The first drive pulley channel and the second drive pulley channel of the drive pulley and the first tension pulley channel and a second tension pulley channel of the tension pulley are configured and arranged to engage and route the endless looped member. The tension adjustment system is coupled to adjust the distance between the drive pulley and the tension pulley. The drive assembly has a drive shaft. The drive assembly is configured to rotate the drive shaft. The drive pulley is in rotational communication with the drive assembly. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The present invention can be more easily understood and further advantages and uses thereof will be more readily apparent, when considered in view of the detailed description and the following figures in which: 
         FIG. 1  is a side perspective view of a climb assist system of one embodiment of the present invention; 
         FIG. 2A  is an assembled side perspective view of a drive assembly of one embodiment of the present invention; 
         FIG. 2B  is an unassembled side perspective view of the drive assembly of  FIG. 2A ; 
         FIG. 3  is a front perspective view of a ladder climb assembly including a tension assembly, an upper pulley assembly and a lower pulley of one embodiment of the present invention. 
         FIG. 4A  is a partial assembled front view of the tension assembly of one embodiment; 
         FIG. 4B  is a partial unassembled side perspective view of the tension assembly of  FIG. 4A ; 
         FIG. 5  is a partial assembled side perspective view of the tension assembly of  FIG. 4A  and the drive assembly of  FIG. 2A ; 
         FIG. 6  is a partial assembled front perspective view of the tension assembly of  FIG. 4A  engaging an endless looped member; 
         FIG. 7A  is a partial front view of the upper pulley assembly of the climb assist system of  FIG. 1 ; 
         FIG. 7B  is a cross sectional side view along line  7 B- 7 B of the upper assembly of  FIG. 7A ; and 
         FIG. 7C  is an unassembled upper pulley assembly of the climb assist system of  FIG. 1 . 
     
    
    
     In accordance with common practice, the various described features are not drawn to scale but are drawn to emphasize specific features relevant to the present invention. Reference characters denote like elements throughout Figures and text. 
     DETAILED DESCRIPTION 
     In the following detailed description, reference is made to the accompanying drawings, which form a part hereof, and in which is shown by way of illustration specific embodiments in which the inventions may be practiced. These embodiments are described in sufficient detail to enable those skilled in the art to practice the invention, and it is to be understood that other embodiments may be utilized and that changes may be made without departing from the spirit and scope of the present invention. The following detailed description is, therefore, not to be taken in a limiting sense, and the scope of the present invention is defined only by the claims and equivalents thereof. 
     Embodiments of the present invention provide a climb assist system  100  with a tension assembly  200  that provides a significant amount of tensioning in a relatively small configuration to ensure proper operation of the climb assist system. In particular, embodiments employ a double pulley arrangement described in detail below.  FIG. 1  illustrates a perspective view of the climb assist system  100  of one embodiment. The climb assist system  100  includes a drive assembly  120  that is coupled to a tension assembly  200 . The drive assembly  120  is designed to move an endless looped member  400  such as, but not limited to, a cable, belt or the like. The endless looped member  400  is coupled between an upper pulley assembly  320  and a lower pulley assembly  300 . In particular, each of the upper and lower pulley assemblies  300  and  320  includes a pulley  340  (shown in  FIG. 7A through 7C ) in which the endless looped member  400  is routed around. The upper pulley assembly  320  is coupled to an upper rung  110   b  of a ladder  110  that the climb assist system  100  is coupled to via connector that includes a connector plate  324  and fasteners  326   a  and  326   b  as discussed below in regards to  FIGS. 7A through 7C . The lower pulley assembly  300  is coupled to lower rung  110   a  of the ladder  110  via similar connector system. Positioned between the lower pulley assembly  300  and the upper pulley assembly  320  is the tension assembly  200  and the drive assembly  120 . The tension assembly  200  further includes similar connectors to couple the tension assembly  200  to rungs  110   c  and  110   d  of the ladder  110 . The connectors of the tension assembly  200  are further described in regards to  FIGS. 4A and 4B  discussed below. 
     As illustrated in  FIG. 1 , the endless looped member  400  is routed through the tension assembly  200 . As further described below in detail, the drive assembly  102  rotates a drive pulley  230  (illustrated in  FIG. 4A ) that is engaged to move the endless looped member  400 . A connecting member  420  coupled to the endless looped member  400  is coupled to a safety harness that is donned by a worker via connector aperture  422 . When the worker is required to climb or descend the ladder  110 , the worker connects his or her safety harness to the connector aperture  422  of the connector member  420 . The drive assembly  120  then provides lift to the worker by moving the endless looped member  400  as the worker climbs or descends the ladder  110 . The lift provided to the worker by the climb assist system  100  helps prevent fatigue. 
     An embodiment of the drive assembly  120  is illustrated in  FIGS. 2A and 2B . In particular,  FIG. 2A  illustrates drive assembly  120  in an assembled configuration while  FIG. 2B  illustrates the drive assembly  120  in a disassembled configuration. The drive assembly  120  of this embodiment includes a first housing portion  122  and a second housing portion  124 . The first housing portion  122  includes a first handle portion  122   a  and the second housing portion  124  includes a second handle portion  124   a  that forms a handle when the first and second housing portions  122  and  124  are coupled together via fasteners  119 . A motor  130  is received inside the first and second housing portions  122  and  124 . The motor  130  turns a drive shaft  150  which is coupled to the drive pulley  230  of the tension assembly which is further discussed below. The second housing portion  124  includes a side  121  with an opening  123 . A mount plate  134  is coupled to the side  121  of the second housing portion  124  to cover a portion of the opening  123  via fasteners  138  and  140 . The mount plate includes a drive shaft passage  134   a . When assembled, the drive shaft  150  of the motor  130  passes through the drive shaft opening  123  of the mount plate  134  while the motor  130  is mounted to the mount plate  134  via fasteners  131 . 
     The drive assembly  120  further includes controller  132  that controls operation of the motor  130 . In this embodiment, the controller  132  includes a housing that is coupled to a controller mounting plate  133  that has edges  133   a  and  133   b  that are received in tracks  117   a  and  117   b  in a cavity in the second housing portion  124  to hold the controller  132  in place. The first housing portion  122  would also have similar tracks to hold a portion of the edges  133   a  and  133   b  of the controller mounting plate  133  when the drive assembly  120  is assembled. Also shown is an emergency stop button  126  that is connected to the first housing portion  122 . In particular, a portion of the emergency stop button  126  is received through a back passage  122   b  of the first housing portion  122 . The emergency stop button  126  is in communication with controller  132 . Upon the depression of the emergency button  126 , the controller stops the motor  130 . Also illustrated in  FIG. 2B , is an electrical connector that is used to provide power to the controller  132  and motor  130  in an embodiment. The electrical connector is coupled to the first housing portion  122  and is in electrical communication with the controller  132  and the motor  130 . 
       FIG. 3  illustrates a kit portion of the climb assist system  100  that is coupled to a ladder. The kit portion includes the tension assembly  200 , the upper pulley assembly  320  and the lower pulley assembly  300 . The upper pulley assembly  320  includes a pulley housing  322  and an upper pulley cover  321 . Extending from a top of the pulley housing  322  is a connector. The connector includes spaced fasteners  326   a  and  326   b  that extend from the housing  322  and a connection plate  324  coupled to the fasteners. The tension assembly  200  includes a housing  202  and a cover  204 . A top portion of the housing  202  includes a cable passage  206 . As illustrated, the housing portion  204  includes a drive shaft receiving passage  214 . The kit portion also includes the lower pulley assembly  300  as discussed above. The lower pulley assembly  300  includes a housing  302  and a lower pulley cover  303 . The housing  302  of the lower pulley assembly  300  includes a first and a second cable passage  301   a  and  301   b . The upper pulley assembly  320  will have similar cable passages. The lower pulley assembly  300  also has a ladder connector that includes spaced fasteners  306   a  and  306   b  and a connection plate  304  that is coupled to the fasteners  306   a  and  306   b . The upper pulley assembly  320 , lower pulley assembly  300  and the tension assembly  200  are further described in detail below. 
       FIGS. 4A and 4B  further illustrate the tension assembly  200 . In particular,  FIG. 4A  illustrates a side view of the tension assembly housing  202  of the tension assembly  200  without a cover  204  and  FIG. 4B  is an unassembled side perspective view. The tension assembly housing  202  is shown having a top end wall  202   a , an opposed bottom end wall  202   b , a first side wall  202   c , an opposed second side wall  202   d  and a back panel  202   e . In this embodiment, connectors similar to the connectors that couple the upper and lower pulley assemblies  300  and  320  to the ladder  110  is used to couple the tension assembly  200  to the ladder  110 . In particular, a first connector includes a connection plate  218  that is coupled a spaced distance from the second side wall  202   d  of the housing  202 . As second connector includes a connection plate  220  that is coupled a spaced distance from the second side wall  202   d  of the housing  202 . The first connector is further spaced a select distance from the second connector. Referring back to  FIG. 1 , the first connector is coupled to rung  110   c  of the ladder  110  and the second connector is coupled to rung  110   d  of the ladder  110 . Referring back to  FIG. 4B , the top end wall  202   a  of the housing  202  includes a first tension assembly cable passage  206  in which a grommet  207  is positioned. The first tension assembly cable passage  206  is positioned near the second side wall  202   d . The bottom end wall  202   b  of the housing  202  includes a second tension assembly cable passage  208  that is generally aligned with the first tension assembly passages  206 . A grommet  207  is also received in the second tension assembly cable passage  208 . The grommets  207  help to reduce wear on the cable  400 . 
     As discussed above, the housing  202  includes a drive shaft receiving passage  214  that passes through the back panel  202   e . A receiving bushing  216  is positioned around the drive shaft passage  214 . A bearing  228  is received in the receiving bushing  216 . The drive shaft  150  of motor  130  is then in turn received within the bearing  228 . This is further illustrated in  FIG. 5 . A retaining clip  226  is used in part to retain the drive shaft  150  within the drive shaft receiving passage  214 . The drive shaft  150  is positioned within a central receiving passage  230   c  of the drive pulley  230 . The central receiving passage  230   c  is shaped to engage the shape of the drive shaft  150  so that rotation of the drive pulley  230  is locked with the rotation of the drive shaft  150 . A tension rod  232  is received through a rod passage  210  of the bottom end wall  202   b  of the housing  202 . The tension rod  232  has exterior threads  231 . An end of the tension rod  232  is received in a rod guide aperture  205   a  in a rod guide  205  to hold the rod in place in the tension assembly  200 . This is illustrated in  FIG. 6 . Referring back to  FIG. 4B , received on the tension rod  232  is received a bearing  234 , first and second biasing members  236  and  240 , an indicator washer  238 , washer  242 , nuts  244  and  246  and a tension pulley assembly  250 . The bearing  234  is received in rod passage  210  of the tension assembly housing  202 . The indicator washer  238  is positioned between the first and second biasing members  236  and  240 . The indicator washer  238  includes an indicator tab  238   a  that is slidably received in the indication window  211  of the first side wall housing  202   c  of the housing  202 . The indicator tab  238   a  in the indication window  211  conveys a tension of the tension assembly  200 . The tension pulley assembly  250  includes a tension pulley  248  (or tensioning sheave  248 ) and a tension pulley bracket  249 . The tension pulley  248  is rotationally coupled to the tension pulley bracket  249 . The tension pulley bracket  249  further includes a tension adjusting rod passage  249   a  that receives the tension rod  232 . A threaded nut  247  is coupled to a bottom end of the tension pulley bracket  249 . The threaded nut  247  is aligned with the tension adjusting rod passage  249   a  and is threadably engaged with the exterior threads  231  of the tension rod  232 . 
     The tension pulley  248  includes first tension pulley channel  248   a  and a second tension pulley channel  248   b  and the drive pulley  230  (drive sheave  230 ) includes a first drive pulley channel  230   a  and a second drive pulley channel  230   b . The endless looped member  400  (cable) is routed around the tension pulley  248  and the drive pulley  230 . In particular, as illustrated in  FIG. 5 , the cable  400  is configured to have a first loop  400   a  and a second loop  400   b . This double loop arrangement allows for more friction to provide lift. That is, a select amount of friction between the cable  400  and the drive pulley channels  230   a  and  230   b  of drive pulley  230  is needed to convey the motion of rotation of the drive pulley  230  to the cable  400 . The double looped arrangement provides a significant amount of tensioning in a small envelope to provide the needed friction. As illustrated in  FIG. 6 , the first loop  400   a  is received in the first tensions pulley channel  248   a  of the tensions pulley  248  and the first drive pulley channel  230   a  of the drive pulley  230  and the second loop  400   b  is received in the second tension pulley channel  248   b  of the tensions pulley  248  and the second drive pulley channel  230   b  of the drive pulley  230 . As best illustrated in  FIG. 6 , drive pulley  230  is offset from the tension pulley  248 . This arrangement allows the cable  400  to pass between the first tension pulley channel  248   a  of the tension pulley  248  and the second tension assembly cable passage  208  in the bottom end wall  202   b  of the tension assembly housing  202  without interfering with the drive pulley  230 . Likewise, it allows the cable  400  to pass between the second drive pulley channel  230   b  of the drive pulley  230  and the first tension assembly passage  206  in the top end wall  202   a  of the tension assembly housing  202  without interfering with the tension pulley  228 . 
     The biasing members  236  and  240  exert a biasing force on the tension pulley assembly  250  and the tension adjustment rod  232  to help counter stretch in the cable and expansion in the system due to temperature variation that can affect the tension in the cable  400 . This biasing force on the tension pulley  248  away from the drive pulley  230  applies tension in the cable  400 . Once the climb assist system  100  is mounted on the ladder  110 , the amount of tension in the cable can be adjusted by rotating the tension adjustment rod  232 . Rotation of the tension adjustment rod  232  is accomplished by turning a manipulation head  233  (manipulation end) of the rod  232  with a tool such as a wrench or the like. As discussed above, the indicator tab  238   a  of the indicator washer  238  (positioned between the biasing members  236  and  240 ) in the indicator window  211  of the tension assembly housing  202  provides an indication of the tension on the cable  400 . Hence, if the cable  400  stretches during use, as indicated by the position of the indicator tab  238   a  in the window  211 , the tension adjustment rod  232  can be rotated to adjust the tension. 
     An illustration of the upper pulley assembly  320  is illustrated in  FIGS. 7A through 7C . The lower pulley assembly  300  in an embodiment is the same as the upper pulley assembly  320 . The upper pulley assembly  320  includes the housing  322  and the cover  321 . The housing  322  includes a back panel  322   a , a first end wall  322   b , a second end wall  322   c , a first side wall  322   d  and a second side wall  322   e . Proximate a central location of the back panel  322   a  of the housing  322 , a pulley post  330  (sheave post) is mounted. The pulley post  330  includes a first spacing portion  330   a  and a second holding portion  330   b . A pulley  340  (sheave) is rotationally mounted on the second holding portion  330   b  of the pulley post  330 . The first spacing portion  330   a  spaces the pulley  340  from the back plate  322   a  of the housing  322 . As illustrated in  FIG. 7C , washers  344  and  342  are also received on the second holding portion  330   b  of the pulley post  330  on either side of the pulley  340 . A C-clip  346  is received in C-clip groove  331  in the second holding portion  330   b  of the pulley post  330  to retain the pulley  340  on the post  330 . Also illustrated in  FIG. 7C  is a pair of spaced bores  321   a  and  321   b  in the first end wall  322   b  in which fasteners  326   a  and  326   b  are connected to form a connector with the connection plate  324 . As illustrated, the fasteners  326   a  and  326   b  pass through bores in the connection plate  324 . The connector including the fasteners  326   a  and  326   b  and the connection plate  324 , as discussed above, couple the pulley assembly  320  to a rung of a ladder  110 . As best illustrated in  FIG. 7C , the second end wall  322   c  of the housing  322  includes two spaced cable passages  323   a  and  323   b  in which the cable  400  is routed. Grommets  207  are inserted in the spaced cable passages to lessen the wear on the cable  400 . The cover  321  is mounted on the housing  322  via fasteners  348 . Although the above description describes a climb assist system  100  that includes a cable  400 , any type of endless looped member  400  can be used, such as, but not limited to, rope, belt, webbing and the like. 
     Although specific embodiments have been illustrated and described herein, it will be appreciated by those of ordinary skill in the art that any arrangement, which is calculated to achieve the same purpose, may be substituted for the specific embodiment shown. This application is intended to cover any adaptations or variations of the present invention. Therefore, it is manifestly intended that this invention be limited only by the claims and the equivalents thereof.