Ski Pole Of Adjustable Length

Abstract

A ski pole of adjustable length with two telescopic tubular pole sections which may be axially locked against each other by means of a clamping element. The clamping element is a pressure element of nonmetallic material, the cross-sectional area of which is undivided and may be increased by reducing the axial length of the pressure element. A surface of the pressure element can directly engage the wall surface of the tubular pole section slidably disposed with respect to the pressure element and the materials of the pole section and the pressure element being so paired that a high coefficient of friction is attained. On the other hand, a tightly confined liquid can be used for the pressure element. In order to reduce the axial length of the pressure element, a rod may be provided which pushes against one end of the pressure element which, with its other end, bears against a retainer which is axially fixed with respect to the surrounding tubular pole section.

Description

This invention relates to a ski pole of adjustable length with two telescopic tubular pole sections which may be axially locked against each other by means of a clamping element.

Such a ski pole is known. Its clamping element features a conical body which is secured to the end of the inner tube forming the lower pole section and the free end of which carries a threaded bolt. The outer tube forming the upper pole section has inserted in it an expanding nut which is movable under frictional resistance and which, when the two pole sections are rotated relatively to each other, is screwed onto the screw thread of the conical body and spread apart, pressing and looking the inner tube against the outer tube. This design has the disadvantage that the torque for screwing the expanding nut on the screw thread of the conical body must be transferred by frictional contact from the outer tube section to the expanding nut. This calls for very high manufacturing accuracy, since the expanding nut, in its unloaded condition, must be movable within the tube in order to enable the length of the pole to be adjusted. On the other hand, it must be seated in the tube with a comparatively tight fit for transmission of the torque during screwing on the threaded bolt, which torque may vary within very wide limits, e.g. when the screw thread is corroded.

In an improved, also known, version of this ski pole the outer tube driving the expanding nut is provided with at least one groove engaging a projection on the expanding nut so that the connection between the driving tube and the driven expanding nut is positive rather than frictional. It is a disadvantage of this design that the inner profile of the tube must deviate from the form of a true circle while a circular shape is desirable for the outer profile of the tube. Tubes with such profiles are not commercially available and, therefore, expensive. Because of the deviation from the circular outer contour, the expanding nut cannot be turned on a lathe, which again increases the costs of production.

In a further known ski pole of this kind the clamping element is of cylindrical shape and subdivided into two or more component parts which may be spread against each other by rotating the tubular pole sections, thereby producing the clamping effect between the pole sections. The spreading effect is achieved by providing the component parts of the clamping element with cooperating inclined surfaces so that the cross-sectional area of the clamping element is composed of at least two parts. This clamping element calls for a strong steel spring which brings the component parts together when the clamping element is released from the locked position. The component parts are axially moved against each other, and thus clamped, by means of a threaded bolt and a nut disposed on one section of the pole with a nonpositive connection. It is a disadvantage of this design that the steel spring which holds the component parts together is susceptible to corrosion, as the temperature changes to which a ski pole is exposed will produce condensation in the interior of the pole. A further disadvantage lies in the comparatively high costs of manufacture and assembly. In addition, the nonpositive connection between one section of the pole and the nut disposed on said section is liable to make adjustment of the pole difficult when the movement of the screw thread has become rough, e.g. as a result of corrosion.

A disadvantage which the known types of ski poles have in common lies in the fact that they cannot be securely adjusted with hands numb with cold or with icy gloves, since roughness of movements of the clamping element will cause the hands or gloves to slip on the tubular sections of the ski pole. This is particularly awkward when at the end of a day of skiing the skier wishes to slide the tube sections together in order to stow the poles away in the car. In addition, the risk of corrosion is particularly grave with these types of ski poles in as much as the clamping element will harm the finish of the tube when the length of the pole is adjusted and the pole sections are locked against each other so that abrasion and, as a result of the always present moisture, corrosion are bound to occur even if the clamping sections have been subjected to a surface treatment.

It is the object of this invention to eliminate the disadvantages of the known ski poles and to provide a ski pole which may be easily adjusted in length at any time and still ensures a safe lock. According to the invention, this objective is achieved by providing as clamping element a pressure element of nonmetallic material, the cross-sectional area of which is undivided and may be increased by reducing the axial length of the pressure element. The use of a pressure element which increases its cross-sectional area when its length is shortened provides a simple method of moving the actuation of the clamping arrangement away from the tube sections and into the grip of the pole, dispensing with a rotary motion since a longitudinal movement is all that is required. In this manner, actuation of the clamping element may be so designed that the length of the pole may be readily adjusted even under adverse circumstances. The use of a nonmetallic material for the pressure element eliminates corrosion and resulting failures and troubles on this part. Furthermore, such a pressure element is very cheap and easy to manufacture. The pressure element may, for instance, consists of a hose section of a material having the elasticity of rubber, a requirement met by a plurality of materials, such as rubber, silicone rubber, soft PVC etc.

In one embodiment of the invention, a surface of the pressure element directly engages the wall surface of the tubular pole section slidably disposed with respect to the pressure element, the materials of the pole section and the pressure element being so paired that a high coefficient of friction is attained. The advantage of this embodiment of the invention lies in the fact that if the materials are paired in a suitable manner the loading and pressing forces required to achieve sufficient adhesion between the two parts that may be axially displaced with respect to each other are comparatively low.

However, the use of solid materials for the pressure element is not indispensable for the ski pole according to the invention. For example, one embodiment of the invention provides for the use of a tightly confined liquid, in particular hydraulic oil, for the pressure element. Today, the sealing problem can be considered as solved even for inexpensive mass-produced articles, as is proved by the example of the motor vehicle shock absorber. In order to further simplify the sealing problem and to further reduce the costs of manufacture by permitting wide tolerances, one embodiment of the invention provides for the liquid to be confined in a liquidtight bag. This bag has approximately the same shape as the surrounding cavity and seats against the wall so that it is not subjected to any special stresses since it merely transmits the pressure existing in the liquid to the surrounding walls, bridging small gaps and fissures. The use of this bag also enables the pressure elements to be assembled and disassembled in a very simple and neat fashion inasmuch as there are no open liquids to be handled. Furthermore, the exact amount of liquid can be metered with ease and reliability. The use of a liquid for the pressure element affords the substantial advantage of ensuring a completely uniform transmission of forces to the surrounding walls so that the tubular pole sections are properly locked against each other on a large area. Furthermore, all embodiments of the invention enable the pressure element to be subdivided into several sections disposed one behind the other in the axial direction, which may afford certain advantages from an operational or production point of view.

In order to reduce the axial length of the pressure element, a rod may be provided which pushes against one end of the pressure element which with its other end bears against a retainer which is axially fixed with respect to the surrounding tubular pole section. An eccentric which displaces the rod relatively to the retainer may be accommodated in the pole grip. A favorable arrangement is one in which the eccentric is operated by means of a lever which, with the clamping element in the loaded position, seats against the pole grip or lies in a recess of the pole grip so that it does not interfere with the use of the ski pole. On the other hand, such a lever is easy to operate at all times, even with hands that are numb with cold or with icy gloves.

In one embodiment of the invention the position of the rod is longitudinally adjustable relatively to the eccentric. This has the advantage that the lengths of the rod and the tube surrounding the rod need not be matched very accurately, since differences may be compensated by adjusting the position of the rod relative to the eccentric and thus also relative to the tube surrounding the rod, which tube is disposed in a fixed position with respect to the eccentric. A further advantage lies in the fact that in this manner the tension of the pressure element may be readjusted at any time, e.g. when the tension of the pressure element has dropped as a result of aging. Furthermore, this arrangement enables the tension to be readily adapted to varying requirements. For example, a tension may be selected which while safely fixing the adjusted length of the pole during skiing will yield to unduly strong forces so that the pole is shortened in a telescoping motion. As the pole telescopes under comparatively strong friction, a certain amount of energy is consumed by friction so that a safety effect is achieved, e.g. when the skier falls frontally against the pole. The rod may be provided with an adjusting nut seated against the surface of the eccentric facing away from the pressure element, as envisaged on one embodiment of the invention. The eccentric shaft may either be supported in the grip of the pole or the periphery of the eccentric, according to a further development of the invention, deviates from the form of a true circle and the circumference of the eccentric bears against a thrust plate. To prevent the eccentric from working itself loose, the thrust plate may be provided with a depression which ensures that the eccentric will be reliably retained in the clamp and, possibly, also in the unclamped position. Alternatively, the thrust plate may be of level construction if, according to a further embodiment of the invention, the eccentric is so guided in the ski pole as to be movable in the axial direction of the rod. In this case, the sidewalls adjacent to the eccentric are provided with grooves extending in the axial direction of the rod, said grooves engaging pins secured to the eccentric.

In a preferred embodiment of the invention the adjusting nut may be adjusted from outside. This arrangement enables the desired holding force between the two pole sections to be readily adjusted at any time. Alternatively, the rod may be arranged for actuation by means of a screwable component located in the grip of the pole, said component engaging the rod end for axially shifting the rod relatively to the retainer. The pole grip may be constructed in two parts, one part having secured to it one of the two tubular pole sections and the other part being provided with an internal thread which is screwed onto the rod provided with an external thread and thus produces an axial movement of the rod through a rotary motion.

In a preferred embodiment of the invention, the rod extends through the center of the pressure element and acts upon the end of the pressure element facing away from the grip of the pole while the retainer takes the form of a tube concentrically disposed to the rod and secured to the surrounding tubular pole section or the grip of the pole. An equally feasible arrangement is one in which the rod acts on the end of the pressure element facing towards the grip of the pole and in which the retainer, against which the other end of the pressure element is seated, serves as an end cover which is axially fixed in the surrounding tubular pole section, said pole section forming the inner tube of the telescopic arrangement and being connected to the grip of the pole.

A practical arrangement for all embodiments of the invention is one in which a spring forces the rod into the unloaded or released position of the pressure element. This spring can be dispensed with if the eccentric and that portion of the surface of the recess in the pole grip accommodating the eccentric which lies adjacent to the circumference of the eccentric are so designed that the rod will be forced into the position corresponding to the unloaded position of the pressure element when the eccentric is released.

Generally, the tube adjacent to the grip of the pole is the outer tube and the tube carrying the point of the pole is the inner tube of the telescopic arrangement. In this manner, the ingress of snow or melted snow and ice into the interior of the telescopic arrangement is largely prevented without the use of any further auxiliary means.

In one embodiment of the invention that end of the inner tube forming the lower pole section which fits in the outer tube is provided with a collar which, at the same time, serves as a stop and extension-limiting device so that the ski pole cannot be inadvertently disassembled into its two constituent tube sections, the ingress of dirt and major foreign bodies being thus positively prevented.

The ingress of dirt and other foreign bodies can also be prevented by fastening a scraper which covers the gap between the outer and inner tube sections at the end of the outer tube section, as envisaged in one embodiment of the invention. A further development of this embodiment of the invention provides for a scraper having a scraper lip seated against the outer surface of the inner tube section and wiping off the dirt that may adhere to the tube of smaller diameter when the two tube sections are displaced with respect to each other.

In one embodiment of the invention a scraper ring is envisaged in a chamber formed by the two tube sections and the scraper. In this manner, a dust and liquid tight seal is provided at this point by which the interior of the pole may be sealed off against the outside.

The invention will now be further described and explained with reference to the specific embodiments shown by way of example in the accompanying drawing. In other embodiments of the invention, the features apparent from the embodiments shown by way of example may be applied separately or in any desired combination.

In the accompanying drawing:

FIG. 1 is a longitudinal section through part of a ski pole with the pressure element in the unloaded or released position;

FIG. 2 shows the pressure element according to FIG. 1 in the loaded or applied position;

FIG. 3 shows a pole grip with an eccentric as actuator for the pressure element;

FIG. 4 shows a pole grip in two parts with a screw-type actuating arrangement for the pressure element;

FIG. 5 shows a pressure element filled with liquid;

FIG. 6 shows a scraper;

FIG. 7 is a longitudinal section through another embodiment of the invention; and

FIG. 8 is a section along line VIII-VIII of FIG. 7.

The adjustable-length ski pole features two telescopic tubular pole sections 1, 2. The tube section 1 is fastened to a pole grip assembly 19 while the tube section 2 carries a snow ring and a point. The pole grip assembly, the snow ring, and the point of the pole are not shown in the drawing. The end of the tube section 1 facing away from the grip of the pole houses a pressure element 3 with a hose section 4 and an elastic sleeve 5 enveloping said hose section. The hose section 4 may, for example, consist of rubber, silicone rubber, soft PVC, or similar materials. The hose section 4 surrounds a tubular pull rod 6, a disc 7 having the same diameter as the hose section 4 being secured to the end of said pull rod by means of a cotter 8. The end of the hose section 4 facing away from the grip of the pole seats against the disc 7. The end of the hose section 4 facing towards the grip of the pole seats against a retainer in the form of a flange bushing 9 which is so disposed on the pull rod as to be free to move in the axial direction. The flange bushing 9 seats against a tube 10 which concentrically surrounds the pull rod 6 and the other end of which fits in an end plate 11 which closes the tube section 1 towards the pole grip assembly 19 in which the tube section 1 is secured. The end plate 11 is provided with a central bore through which passes the pull rod 6. The pull rod 6 is axially movable with respect to the end plate 11. The flange bushing 9 carries one end of the elastic sleeve 5 extending over the hose section 4 from the flange bushing 9 to the disc 7. The disc 7 is slidably disposed within the elastic sleeve 5.

Near the end plate 11 the tube 10 is provided with two longitudinal slots arranged opposite each other in which a pin 12, the longitudinal centerline of which is disposed perpendicularly to the longitudinal centerline of the ski pole, is free to move in the axial direction of the ski pole. The pin 12 is secured in a transverse bore of the pull rod 6. A ring-shaped thrust washer 13, the inside diameter of which is greater than the outside diameter of the tube 10 and the outside diameter of which is smaller than the inside diameter of the tube section 1, is pressed against the pin 12 by a compression spring 14 which with its other end bears against the end plate 11. The compression spring 14 thus pushes the pull rod 6 in the direction of the print of the ski pole. The end portion of the tube section 2 facing away from the point of the ski pole lies inside the tube section 1. At its extreme end located inside the tube this tube section 2 is provided with a collar 15, the inside diameter of which is smaller than the outside diameter of the flange bushing 9 so that the flange bushing 9 forms a stop for the tube section 2 when this tube section is extended. The outside diameter of the inner tube and the inside diameter of the outer tube of the two tube sections forming the outside of the ski pole are so matched that the two tube sections can telescope with ease. The inside diameter of the inner tube section is slightly larger than the outside diameter of the unloaded pressure element 3. When the pressure element 3 is loaded, which occurs when the pull rod 6 is moved in the direction of the point of the pole, the hose section 4 presses the elastic sleeve 5 against the tube section 2 which under the action of the pressure element snugly fits against the surrounding tube section 1, thus being securely clamped on a large area. All deformations (hose section 4, elastic sleeve 5, tube sections 2, 1) take place below the elastic limits of the materials concerned.

Where sturdy, thick-walled tubes are used which are not sufficiently expanded by the pressure element the tube end of the inner telescopic tube may be provided with longitudinal slots in the zone of the pressure element.

The pole grip assembly 19 shown in FIG. 3 features a one-part hand-conforming-shaped grip 20, preferably made of plastic, in which the tube section 1 and the end plate 11 are fastened. This grip is provided with a recess into which projects the end of the pull rod 6 which through an eccentric shaft 21 is connected to an eccentric lever 22. When the pressure element is in the unloaded condition the eccentric lever assumes the position indicated by the dot-dash lines, whereas in the loaded condition of the pressure element it is located in a longitudinal recess of the grip 20 so as not to disturb the hand-conforming contour of the grip 20. A slightly curved end 23 of the eccentric lever 22 projects from the pole-side end of the grip 20 so that the eccentric lever 22 may be readily swung out of the recess in the grip 20. A strap 25 is fastened to the outer end of the grip 20 by means of a screw 24.

With the pressure element in the unloaded position, the eccentric lever 22 is in the position indicated by the dash-dot lines, the compression spring 14, through the thrust washer 13 and the pin 12, pushes the pull rod 6 in the direction of the pole point. In order to load the pressure element 3, the eccentric lever is swung towards the grip, and eccentric surface 26 bearing against the end plate 11 and moving the pull rod 6 towards the grip by means of the eccentric shaft.

In the pull-rod-actuating arrangement shown in FIG. 4 one grip end 30 is separated from the grip 20 so that the grip assembly 19 consists of two parts. At its grip-side end the pull rod 6 is provided with a threaded bolt 31 at the outer end of which is secured a snapring 32 which prevents a nut 33 from being screwed beyond the end of the threaded bolt 31. The nut 33 is positively embedded in the grip end 30 and is screwed by turning the grip end 30 which may feature a noncircular cross section or a folding handle. One end face of the nut 33 bears against the end plate 11, such that the pull rod 6 may be moved in the axial direction by rotating the sturdily constructed, handy grip section 30, the pressure element being thus loaded or unloaded so as to clamp or unclamp the two tube sections 1, 2 with respect to each other.

Another embodiment of the clamping arrangement according to this invention, in which the pressure element takes the form of a chamber 40 filled with a liquid, is shown in FIG. 5. The chamber 40 is located in the end of the tube section 1 facing away from the pole grip assembly 19, said tube section 1 forming in this embodiment of the invention, the inner tube of the telescopic assembly, the tube section 2 being slid over the tube section 1. At the end of the tube section 1 the chamber 40 is closed by an end cover 36 sealed with an O-ring 37. The end of the tube section 1 is flanged inward and restrains the end cover 36 against axial displacement in the direction of the pole point. The grip-side end of the chamber 40 is closed by a piston 38 sealed by means of an O-ring 39. The chamber 40 contains a liquid, e.g. hydraulic oil. If the liquid in the chamber 40 is confined in a liquidtight bag, the O-rings 37, 39 may be dispensed with, since in that case the sealing requirements are not very exacting. The piston 38 is actuated by means of a rod 41 which corresponds to the pull rod 6 of the other embodiments shown except that, unlike to what occurs in the other embodiments, the pressure element is loaded when the push rod 41 is moved in the direction of the pole point and unloaded when said rod is moved in the opposite direction.

In order to prevent the ingress of dirt, liquid, and dust into the interior of the pole, a scraper 42 is secured to the end of the outer tube section, that portion of said scraper which projects beyond the end of said tube section being reduced to approximately the diameter of the inner tube section. This end forms a scraper lip 45 which contacts, or almost contacts, the outer surface of the inner tube section 2. The outer tube section 1, the inner tube section 2, and the scraper 42 together define a chamber 43 which contains a scraper ring 44, e.g. a felt ring or oil seal.

In the embodiment of the invention with eccentric adjustment, as shown in FIG. 7, the eccentric setting is adjustable, permitting the load on the pressure element to be selected according to varying requirements. For this purpose the pull rod 6 is provided with an extension and passed through a slotted eccentric lever 64. The end which faces towards the eccentric is provided with a screw thread 50 onto which is screwed an adjusting nut 51. This adjusting nut 51 seats against an eccentric surface 52 of the eccentric lever 64 which at its other end bears against the end plate 11. An advantageous design is one in which the eccentric lever 64 is provided with two eccentric surfaces, one eccentric surface 65 bearing against the end plate 11 and the other eccentric surface 52 cooperating with an end face of the adjusting nut 51, thus increasing the stroke of the eccentric. At its end facing away from the eccentric, the adjusting nut 51 is provided with a slot 53 engaged by a driver 54 which is rotatably supported in the pole grip assembly 19 by means of a collar 55. The end of the driver facing away from the adjusting nut 51 extends all the way to the upper end of the pole grip assembly 19 and is provided with a slot 56 in this final portion. At this slot 56, the pole grip assembly 19 features a spherical depression 57 which enables a coin 68 to be inserted into the slot 56 so that the driver 54 and thus the adjusting nut 51 may be rotated with the aid of this coin, with the result that the rod 61 may be moved in the axial direction.

To prevent the slotted eccentric lever 64 from dropping out of the pole, said eccentric lever, at both cheeks or webs 66 and 67 defining the slot on either side, is provided with one retaining pin 58 or 59 slidably disposed in a groove 60 or 61 respectively. The grooves 60 and 61 are worked into the pole grip assembly 19 or else, e.g. with a compression or injection molded plastic pole grip, into metal plates 62 and 63 set into the pole grip assembly 19, e.g. during the injection moulding process. The grooves 60 and 61 extend in the longitudinal direction of the pole so that the eccentric lever 64, which may be swiveled about the retaining pins, while being free to move in the longitudinal direction of the pole when the eccentric is operated, is prevented from moving transversely to that direction, such that the eccentric lever 64 cannot get lost.

The application of the present invention is not restricted to ski poles. It can also be used for the retention of tripods, tent poles, or other telescopic rods including e.g. stretcher frames.

Claims

1. Longitudinally adjustable ski pole with two telescopically displaceable, tubular pole sections which may be axially locked against each other by means of a pressure element made of a material having the elasticity of rubber, which element can be enlarged in cross-sectional area by reducing the axial length thereof, wherein the outer surface of the pressure element engages directly the wall surface of the tubular pole section, which is slidably disposed with respect to the pressure element, and a rod being provided for reducing the axial length of the pressure element, which rod pushes against one end of the pressure element so as to exert a force in the direction toward the pressure element and the other end of the pressure element bearing against a retainer, characterized in that the retainer may be axially fixed with respect to the surrounding tubular pole section, the wall of the inner tubular pole section associated with the tip of the ski pole being disposed between the outer tubular pole section and the pressure element, the materials for the inner pole section and for the pressure element being so paired as to achieve a high coefficient of friction, and a scraper being secured to the end of the outer tube section and covering the gap between the outer and inner tubular pole sections.

2. A ski pole according to claim 1, characterized in that the pole grip assembly houses an eccentric which displaces said rod with respect to said retainer and the longitudinal position of said rod is adjustable with

3. A ski pole according to claim 2, characterized in that said rod is provided with an adjusting nut which seats against the surface of said

4. A ski pole according to claim 2, characterized in that the periphery of said eccentric deviates from the form of a true circle and in that the

5. A ski pole according to claim 2, characterized in that said eccentric is so guided in the ski pole as to be movable in the axial direction of said

6. A ski pole according to claim 2, characterized in that said adjusting

7. A ski pole according to claim 2, characterized in that said eccentric and the surface of the recess in said pole grip assembly, which accommodates said eccentric are so designed that said rod will be forced into the position corresponding to the unloaded position of said pressure

8. A ski pole according to claim 7, characterized in that the end of the inner tubular pole section inside the outer tubular pole section is provided with a collar, said collar simultaneously serving as a stop and

9. A ski pole according to claim 1, characterized in that a component which may be screwed in the axial direction is disposed in a pole grip assembly, said component engaging the end of said rod for axially displacing said

10. A ski pole according to claim 1, characterized in that said rod extends through the center of said pressure element and acts upon the end of said pressure element facing away from a pole grip assembly and in that said retainer is provided with a tube concentrically disposed with respect to

11. A ski pole according to claim 10, characterized in that a spring is provided which forces said rod into the unloaded or released position of

12. A ski pole according to claim 1, characterized in that said scraper is provided with a scraper lip which contacts the outer surface of the inner

13. A ski pole according to claim 12, characterized in that a scraper ring is provided in a chamber defined by the two tubular pole sections and said scraper.