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.
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.
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:
An embodiment of a telescoping adjustable pole having a clamping mechanism is described below.
The clamping mechanism 20 is illustrated in detail in
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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
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
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
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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'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.
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.
Number | Date | Country | |
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61095900 | Sep 2008 | US |