Patent Publication Number: US-2010123304-A1

Title: Telescoping adjustable pole

Description:
CROSS-REFERENCE TO RELATED APPLICATION 
     The present application claims the benefit of U.S. Provisional Patent Application No. 61/095,900, filed Sep. 10, 2008, the disclosure of which is hereby expressly incorporated by reference in its entirety. 
    
    
     BACKGROUND 
     Telescoping adjustable length poles are known in the art. There are downhill adjustable ski poles, backcountry adjustable ski poles, trekking poles, and the like, that are available on the market. The purpose of such poles is to accommodate athletes, such as skiers or hikers, of different height. Another purpose is to accommodate exercising, such as skiing, under variable conditions, with a single set of adjustable length poles. 
     There are two types of clamping mechanisms used for adjustable length poles that are known in the art: internal and external mechanisms. Internal mechanisms are located on the inside of the outer tubing portion of the pole. Internal mechanisms allow for a lower profile pole, can offer a lower swing weight, and are less prone to catching or interfering with other nearby objects. However, internal mechanisms have serious disadvantages: typically, they have problems with slipping during use, or, conversely, they tend to lock the ski pole and hinder the user from loosening the mechanism to adjust the pole. The locking tendency may be caused by ice accumulation, for example by ice freezing in the mechanism, or ice lining the inside of the pole causing the mechanism to spin without engaging or loosening the clamp. Because the mechanism is internal, there is no easy way to access it in the field for maintenance. 
     External mechanisms are generally located on the outside of the pole, and have been developed to overcome performance issues of the internal mechanisms. Because an external mechanism is affixed to the outside of a pole, it is readily accessible for troubleshooting and maintenance. The key disadvantages of external mechanisms known in the art are that external clamping mechanisms tend to be more bulky and add swing weight to a pole, relative to internal mechanisms. 
     External clamping mechanisms may generally be divided into two types. A first type clamps the outer pole shaft to the inner pole shaft, and a second type is affixed to the outer pole shaft and clamps only around the inner pole shaft. The second type of external mechanism allows the use of composite materials for the outer tubing, whereas the first type generally requires that the outer pole shaft be formed from a material that can be flexed repeatedly and is fatigue resistant, such as an aluminum alloy. Therefore, because of the flexibility in using composite materials for the tubing, the second type of the clamping mechanisms is preferable. However, even the mechanisms of the second type that are known in the art have exhibited serious shortcomings related to the lack of locking force, low reliability, awkward handling, bulkiness, etc. 
     Therefore, there remains a need for improvements to adjustable length telescoping poles, including clamping mechanisms therefore. 
     SUMMARY 
     This summary is provided to introduce a selection of concepts in a simplified form that are further described below in the Detailed Description. This summary is not intended to identify key features of the claimed subject matter, nor is it intended to be used as an aid in determining the scope of the claimed subject matter. 
     A telescoping adjustable ski pole having a clamping mechanism for locking an inner shaft of the pole in a desirable position is disclosed. In one embodiment, the telescoping adjustable ski pole comprises an outer shaft having an open end, an inner shaft having a first end slidably disposed in the open end of the outer shaft; and a releasable clamping mechanism. 
     The releasable clamping mechanism includes a housing having a tubular portion attached to the open end of the outer shaft and a split portion extending axially from the tubular portion, the split portion defining a longitudinal gap having a gap width. The split portion comprises a first lug on a first side of the gap and a second lug on an opposite side of the gap. 
     The releasable clamping mechanism further includes a lever having a first end pivotably connected to the first lug at a first pivot, a second end defining a thumb panel having a concave inner surface, and an intermediate aperture disposed between the first end and the thumb panel and oriented substantially parallel to the first pivot. The lever is pivotable about the first pivot between a clamping position and a release position. 
     The releasable clamping mechanism also includes a link having a first end pivotably connected to the lever intermediate aperture at a second pivot and a base defining a base aperture therethrough, a pivot rod pivotably disposed through the second lug, and a threaded connector that extends through the base aperture and threadably engages the pivot rod through its intermediate threaded aperture. 
     When the lever is pivoted from the release position to the clamping position, a width of the longitudinal gap in the split portion reduces. The first and second pivots engaged with the lever define an off-center linkage such that the lever is retained in the clamping position. 
     In another embodiment, an adjustable ski pole comprises a tubular outer shaft having a first diameter, a tubular inner shaft having a second diameter smaller than the first diameter, so that the inner shaft slidably engages the outer shaft, and a clamping mechanism. 
     The clamping mechanism comprises a housing having a collar portion attached to the outer shaft and a tubular split portion extending away from the collar portion and slidably engaging the inner shaft. The tubular split portion of the housing has a longitudinal gap and comprises a first connecting member on a first side of the gap and a second connecting member on a second side of the gap. An upper section of the split portion is separated from the collar portion with a circumferential slot. 
     The clamping mechanism also includes a lever having a base portion pivotably attached to the first connecting member, a curved panel disposed away from the base portion, and an intermediate aperture between the base portion and the panel. The lever is movable between an engaged position, wherein the upper section of the split portion clampingly engages the inner shaft, and a released position, wherein the split portion does not clampingly engage the inner shaft. The clamping mechanism further includes a linking element having a first end pivotably attached to the lever intermediate aperture, and a second end pivotably attached to the second connecting member. 
    
    
     
       DESCRIPTION OF THE DRAWINGS 
       The foregoing aspects and many of the attendant advantages of this invention will become more readily appreciated as the same become better understood by reference to the following detailed description, when taken in conjunction with the accompanying drawings, wherein: 
         FIG. 1  is a fragmentary side view of a telescoping adjustable pole with a clamping mechanism in accordance with the present invention; 
         FIG. 2  is a front-right perspective view of the clamping mechanism shown in  FIG. 1 ; 
         FIG. 3  is a rear-right perspective view of the clamping mechanism shown in  FIG. 2 ; 
         FIG. 4  is an exploded view of the clamping mechanism shown in  FIG. 2 ; 
         FIGS. 5A and 5B  show different views of the housing for the clamping mechanism shown in  FIG. 2 ; and 
         FIG. 6  is a cross-sectional view of the clamping mechanism shown in  FIG. 2 . 
     
    
    
     DETAILED DESCRIPTION 
     An embodiment of a telescoping adjustable pole having a clamping mechanism is described below. 
       FIG. 1  illustrates a telescoping adjustable ski pole  10  having an outer shaft  16  (shown in phantom), an inner shaft  18  (shown in phantom) slidably received by the outer shaft  16 , and a clamping mechanism  20  for locking the inner shaft  18  at a desired position with respect to the outer shaft  16 . The clamping mechanism  20  is fixedly attached to the outer shaft  16  and is shown in a clamping position that locks the inner shaft  18  relative to the outer shaft  16 . The outer shaft  16  includes a conventional handle  14 , as are known in the art. Although not shown in the FIGURES, it will be appreciated that the inner shaft  18  would conventionally include a basket or the like disposed near the distal end. One skilled in the art will recognize that more than two telescoping shafts may be used with additional clamping mechanisms  20 , for example to provide a very compactable ski pole. 
     The clamping mechanism  20  is illustrated in detail in  FIGS. 2-5 .  FIG. 2  is a front-right perspective view of the clamping mechanism  20 ,  FIG. 3  is a rear-right perspective view of the clamping mechanism  20 ,  FIG. 4  is an exploded view of the clamping mechanism  20 ,  FIGS. 5A and 5B  show different views of the housing for the clamping mechanism  20 , and  FIG. 6  is a cross-sectional view of the clamping mechanism  20 . 
     Refer now to  FIGS. 2 and 3 , showing different views of the clamping mechanism  20 . The clamping mechanism  20  is a releasable, off-center linkage system for clamping the telescoping pole&#39;s inner shaft  18  at a fixed longitudinal position with respect to the outer shaft  16 . The clamping mechanism  20  includes: (i) a housing  30  having a tubular portion  32  that is fixedly retained on the outer shaft  16 , and a split portion  34  that releasably engages the telescoping inner shaft  18 ; (ii) a lever  50  that is pivotably attached to the split portion  34  of the housing  30 ; and (iii) a link  80  having one end that is pivotably connected to the lever  50  and the other end pivotably connected to the housing  30 . The inner shaft  18  extends through the split portion  34  to telescopically engage the outer shaft  16 . When the lever  50  is in the clamping position shown in  FIGS. 2 and 3 , it locks the inner shaft  18  at a desired adjustment. 
     Refer now also to  FIG. 4 , which shows an exploded view of the clamping mechanism  20 . The tubular portion  32  of the housing  30  receives the end of the outer shaft  16  and is fixed thereto. For example, the housing  30  may be retained on the outer shaft  16  by a friction fit, an interference fit, with an adhesive material and/or using conventional attachment hardware (not shown). The tubular portion  32  optionally includes an inwardly-disposed flange or stop  31  that is sized to abut a top edge of the outer shaft  16 . 
     Refer now also to  FIG. 5A , which shows a front view of the housing  30  in isolation. The split portion  34  of the housing  30  is integral with the tubular portion  32 , and extends axially from the tubular portion  32 . The split portion  34  is generally a split tubular member sized to slidably receive the inner shaft  18 , and having a longitudinal gap  36  along the entire length of the split portion  34 . 
     A first lug  38  extends outwardly from one side of the gap  36 , defining a first axial aperture  39  therethrough. A pair of second lugs  40  extend outwardly from the opposite side of the gap  36 , defining a second axial aperture  41 . 
     A circumferential slot  42  extends circumferentially around the housing  30  between the tubular portion  32  and the split portion  34 . As will be appreciated from 
       FIG. 4 , the section of the split portion  34  supporting the first lug  38  comprises a reduced-thickness panel  44 . In this embodiment, the circumferential slot  42  extends for at least half the circumference of the split portion  34 . The housing  30  is formed form an elastic semi-rigid material, for example a semi-rigid polymer, such that the split portion  34  can be compressed by narrowing the longitudinal gap  36 . In particular, an upper section  46  of the split portion  34  is supported only along a longitudinal side. The upper section  46  is essentially cantilevered and curved to approximately match the curvature of the housing split portion  34 . The upper section  46  can therefore flex inwardly with ease, relative to the lower section  47  of the split portion  43 . It will now be apparent from the FIGURES that the clamping mechanism  20  operates by urging the upper section  46  of the split portion  34  inwardly to clamp the inner shaft  18 , or releasing the upper section  46  to release the clamping force on the inner shaft. 
     The lever  50  includes a thumb panel  52  and base portion  54  comprising spaced apart arms  56  having axially aligned apertures  58  therethrough. As will be apparent from  FIG. 4 , the arms  56  are spaced apart to receive the first lug  38  therebetween. The lever  50  is pivotably attached to the first lug  38  with a first pivot  60  that passes through the axially aligned apertures  58 , and the first axial aperture  39 . 
     The base portion  54  of the lever  50  further comprises an intermediate aperture  62  disposed near the thumb panel  52  and oriented generally parallel to the axially aligned apertures  58 . 
     The thumb panel  52  preferably is curved, having a concave inner surface that matches a convex outer surface of the housing  30 . In one embodiment (not shown) the thumb panel  52  extends axially beyond the end of the housing  30  to form a ledge such that the lever  50  overhangs the housing  30 . This configuration provides a small ledge to push against so as to assist in gloved operation of the clamping mechanism  20 . As seen most clearly in  FIG. 6 , the lever thumb panel  52  may include an end tab portion  53  that is oriented to extend away from the housing  30  when in the clamped position, to facilitate releasing the lever  50 . 
     Still referring to  FIG. 4 , the link  80  is a generally U-shaped element having spaced apart arms  82  and a connector portion  84  therebetween. The arms  82  are spaced to receive the base portion  54  of the lever  50  therebetween. The arms  82  include axially aligned apertures  86 . The link  80  is pivotably connected to the lever  50  by a second pivot  90  that extends through the axially aligned apertures  86  in the link  80  and the intermediate aperture  62  in the lever  50 . The connector portion  84  of the link  80  includes a through hole  88 , discussed below. A rod  92  having a transverse threaded aperture  94  therethrough is inserted through the second axial apertures  41  in the second pair of lugs  40  on the housing  30 . A threaded connector such as a bolt  96  extends through the through hole  88  in the connector portion  84  of the link  80 , and engages the transverse threaded aperture  94  in the rod  92 . 
     Refer now also to  FIG. 5B , which shows a back view of the housing  30 . The split portion  34  further comprises spaced-apart circumferential ribs  48  disposed generally on opposite ends of the split portion  34 . The ribs  48  stiffen the lower section  47  of the split portion  34 . Moreover, as will be best appreciated by also referring to  FIG. 2 , the circumferential ribs  48  define a channel therebetween that partially receives the distal end of the lever  50  to protect the lever  50  from inadvertent release or the like. The channel therebetween also provides a convenient guide for the user to be able to engage the end of the lever  50 , e.g., to release the lever  50 . It will be appreciated that this is particularly advantageous for users who will typically be wearing gloves. 
     Refer now again to  FIG. 4 . To assemble the clamping mechanism  20 , the lever  50  is pivotably attached to the first lug  38  on the housing  30  by inserting the first pivot  60  through apertures  58  in the lever  50 , and aperture  39  in the first lug  38 . The link  80  is pivotably attached to the lever  50  by inserting the second pivot  90  through apertures  86  in the link  80  and intermediate aperture  62  in the lever  50 . The link  80  is also connected to the housing  30  by inserting rod  92  through apertures  41  in the second lugs  40 , and inserting the bolt  96  through the through hole  88  in the link  80 , and threadably engaging the threaded aperture  94  in rod  92 . The tubular portion  32  of the housing  30  is fixed to the outer shaft  16 . The inner shaft  18  is slidably inserted through the housing  30  to telescopingly engage the outer shaft  16 . 
     Refer now to  FIG. 6 , which shows a cross section of the clamping mechanism  20  generally through a centerline of the mechanism  20 . The operation of the clamping mechanism  20  can now be understood. When the lever  50  is in the clamping position shown, the split portion  34  of the housing  30  is biased firmly against the inner shaft  18 , thereby locking the axial position of the inner shaft  18  relative to the outer shaft  16 . When the lever  50  is in the release position (shown in phantom) the split portion  34  is not biased towards the inner shaft  18 , and therefore the user can adjust the axial position of the inner shaft  18 . 
     It will be appreciated that the tubular portion  32  of the housing is simply fixed to the outer shaft  16 , and the clamping mechanism  20  clamps only around the inner shaft  18 . In particular, the clamping mechanism  20  performs the task of locking the ski pole  10  in a desired adjustment. Moreover, when the clamping mechanism  20  is in the clamping or locked position, the inner shaft  18  is engaged about substantially it&#39;s entire periphery, providing good locking performance, and relatively uniform clamping stresses in the inner shaft  18 . This construction is particularly suited to forming the outer and inner shafts  16 ,  18  from a composite material. Composite construction of the outer and inner shafts  16 ,  18  enables the ski pole  10  to be very light weight, while providing the required structural performance. Therefore the ski pole  10  can have a swing weight. 
     Another aspect of the disclosed embodiment is that the split portion  34  of the housing  30  which engages only the smaller diameter inner shaft  18 , may be of smaller diameter than the tubular portion  32  which engages the outer shaft  16 . This provides a more compact construction. 
     While illustrative embodiments have been illustrated and described, it will be appreciated that various changes can be made therein without departing from the spirit and scope of the invention.