Background Art Slalom poles are anchored in a base which usually is a layer of snow or ice on a ski-slope. In many cases the anchoring is made by drilling a hole in the base, where- upon the pole or an anchoring device connected to the pole is fixed in the base. It is desirable for the slalom pole to be fixable in and removable from the base in a quick and easy manner. At the same time a slalom pole fixed in the base must be held in a stable manner even if subjected to impacts and blows, for instance when a skier runs into it.

EP-0 063 254 discloses a slalom pole with an anchor- ing device of the type stated by way of introduction, in which a threaded operating rod with a conical end can be screwed into an internally conical gripping sleeve with a view to expanding the gripping sleeve to engage in a surrounding layer of snow.

This anchoring device, however, suffers from the drawback that it takes a long time to screw it in posi- tion and also to unscrew it. Further the operating rod of a fastened anchoring device of this type may be unscrewed when subjected to blows and impacts, and then the associated slalom pole is no longer firmly anchored.

Moreover the tendency towards this kind of self-unscrew- ing increases by the fact that the operating rod in the fastened position is all the time subjected to an unscrewing force caused by the tension in the expanded gripping sleeve.

Summary of the Invention An object of the present invention is to provide an improved anchoring device for a slalom pole.

A special object is to provide an anchoring device which can quickly and easily be fixed in and removed from a base on a ski slope.

According to the invention, these and other objects that will appear from the following description are now achieved by means of a device which is of the type described by way of introduction and in addition has the features defined in the characterising clause of claim 1.

The inventive anchoring device thus comprises an operating rod which is axially slidably movable between a resting position and a gripping position in a gripping sleeve provided with axial slots. The outside of the rod or the inside of the sleeve is formed with at least one tapering portion, i. e. a portion, in which the area of the radially extending cross-section which is defined by the contour of the surface decreases in an axial direc- tion. The tapering portion is arranged such that the gripping sleeve, by cooperation between said outside and said inside, at least partially is radially expanded in the gripping position. Stop means are arranged to prevent displacement of the operating rod past the resting posi- tion and the gripping position, respectively. A holding means in the form of a snap means or a friction means is arranged to hold the operating rod in the gripping posi- tion.

Thanks to the axial sliding displaceability between the rod and the sleeve, the anchoring device can quickly and easily be moved between the resting position and the gripping position in a linear motion.

The stop means define end positions of the axial motion, a resting position and a gripping position, and prevent mutual displacement between the operating rod and the gripping sleeve past one of the end positions. It is simultaneously ensured that the operating rod and the

gripping sleeve remain an assembled unit, both when using and during storage and transport of the anchoring device.

The stop means can advantageously be designed as axially directed, cooperating abutment surfaces of the gripping sleeve and the operating rod, respectively.

The holding means ensures that the operating rod is not unintentionally removed from the gripping position.

The anchoring device can thus be stably anchored in a base on a ski slope and remain stably anchored even if subjected to impacts and blows. The holding means can be designed either as a snap means with two cooperating parts snapping together in the gripping position, or as a friction means generating high friction between the sleeve and the rod in the gripping position.

Preferred embodiments of the invention are stated in the subclaims.

In a preferred embodiment, the gripping sleeve com- prises slots extending from one end. The tapering portion is arranged to expand the gripping sleeve in the slotted area.

It is particularly preferred that the two ends of the gripping sleeve be slotted and that two tapering por- tions be arranged to expand, in the gripping position, a slotted area each of the gripping sleeve. As a result, the gripping sleeve expands in two ends, which results in enhanced engagement in the surrounding base. The two tapering portions are preferably arranged such that the gripping sleeve in the gripping position is expanded over the major part of its length. In a particularly preferred embodiment, the sleeve has on its inside a downwardly tapering surface portion in the area of its lower slots, and the operating rod has a downwardly tapering portion in an upper area to cooperate, in the gripping position, with the upper slots of the gripping sleeve.

By the reference directions upwards and downwards and the corresponding qualifications are meant, in con-

nection with the present invention, the qualifications that apply to an anchoring device mounted in a base.

In another preferred embodiment, a radially out- wardly extending abutment means is arranged on the grip- ping sleeve at the upper end thereof. This abutment means defines, by engaging the base, the end position for the insertion of the sleeve into the base when the device is in the resting position.

Brief Description of the Drawings The invention will now be described in more detail with reference to the accompanying drawings, which illu- strate a currently preferred embodiment of the invention and in which Fig. 1 is a side view of a gripping sleeve; Fig. 2 is a longitudinal section of the gripping sleeve in Fig. 1; Fig. 3 is a top plan view of the gripping sleeve, seen along III-III in Fig. 1; Fig. 4 is a side view of an operating rod; Fig. 5 is a side view of the operating rod accord- ing to Fig. 4, the operating rod being rotated through 45° about its longitudinal axis relative to the side view shown in Fig. 4; Fig. 6 is a longitudinal section of the operating rod according to the view shown in Fig. 4; Fig. 7 is a longitudinal section of the operating rod according to the view shown in Fig. 5, a portion of the outside of the operating rod being shown on a larger scale; Fig. 8 shows, in a resting position, an anchoring device with operating rod and gripping sleeve assembled; and Fig. 9 shows the anchoring device according to Fig. 8 in the gripping position.

Description of an Embodiment of the Invention Figs 1-3 show a gripping sleeve 10 belonging to an anchoring device according to the invention. When in use,

the sleeve 10 is adapted to cooperate, with its outside, with a surrounding base in a fixing hole, which can either be predrilled or formed as the gripping sleeve 10 is being driven in. The sleeve is adapted to be connected with a slalom pole via an operating rod extending on the inside of the sleeve.

The sleeve 10, which preferably is made of plastic or some other elastic material which to some extent is rigid, is elongate and circular in cross-section and has a lower and an upper end 19,20. At the upper end 20, the sleeve 10 has an upper flange portion 23 comprising a radially projecting annular flange 24 and an annular shoulder 25 extending axially upwards from the circum- ference of the flange. The flange portion 23 defines two upwardly directed abutment surfaces 13 and a downwardly directed abutment means 9. The function of the flange portion will be described in more detail below.

From the flange portion 23 in the upper end 20 of the sleeve 10 extends a straight upper sleeve portion 26, in which the internal surface of the sleeve 10 is cylin- drical, downwards to a conical portion 27. In the upper sleeve portion 26, the sleeve 10 has axially extending slots 16. The slots 16 which are four in number and are distributed at an angle of 90° relative to each other, extend from the upper end 20 to the conical portion 27.

Thanks to the slots 16 and the elasticity of the sleeve material, the sleeve 10 is radially expandable in the upper portion 26.

An annular recess 14 is formed on the inside of the sleeve 10 in the upper portion 26 to serve, in coope- ration with a corresponding means on the operating rod, as a holding means, as will be described in more detail below.

In the conical portion 27, the sleeve has a down- wardly tapering inner surface portion in the form of a truncated conical portion 11. The conical portion 27 extends to a straight lower portion 28, in which the

truncated conical surface portion 11 passes into a cylin- drical surface which has a smaller diameter than the cylindrical surface in the upper portion 26.

Adjacent to the conical portion 27 and the lower portion 28, the sleeve 10 has radially projecting engag- ing means in the form of circumferentially extending engaging flanges 17, which are adapted to ensure a stable engagement in a surrounding base and to prevent uninten- tional withdrawal of the sleeve 10. Alternatively, the sleeve 10 can be provided with axially extending engaging ribs (not shown) to ensure a non-rotatable engagement in the base.

The lower portion 28 is terminated in the lower end 19 of the sleeve 10 with a pointed portion 29, which extends conically downwards from a lower engaging flange 17 and is adapted to facilitate insertion into a base.

In the pointed portion 29, the internal surface of the sleeve tapers further such that the opening in the lower end has but a small area. This limits the risk of snow and ice penetrating into the sleeve during insertion into a base, thereby facilitating the operation of the operat- ing rod.

Lower axial slots 15 extend from the lower end upwards a distance past the conical portion 27. The slots 15 allow radial expansibility in the lower area of the sleeve 10. The fact that the slots 15,16 overlap each other results specifically in radial expansibility over the entire length of the sleeve 10. This enables, inter alia, simple assembly of the sleeve and the rod. At the upper end of the lower slots 15, there are abutment sur- faces 12, the function of which will be described in more detail below. The upper and lower slots define inerme- diate legs 7,8, such that the sleeve 10 is expanded by outwards bending of the legs 7,8.

Below follows a detailed description of the operat- ing rod 30 with reference to Figs 4-7. The operating rod 30, which is also advantageously made of plastic, is

adapted to be inserted in the gripping sleeve 10 and, at its upper end 40, to be connected to a slalom pole at an invariable axial distance. In the upper end of the ope- rating rod there is a stepped, radially projecting flange portion 43, which comprises abutment surfaces 33 and is adapted to cooperate with the flange portion 23 of the gripping sleeve 10.

The operating rod 30 has a tapering portion, extend- ing from the flange portion 43, in the form of a trun- cated conical surface portion 31 with a small angle of inclination. The conical portion 31 extends to a radially projecting annular flange 34 which is triangular in lon- gitudinal section, as showed on a larger scale in connec- tion with Fig. 7. The annular flange 34 is adapted to form, in cooperation with the annular recess 14 of the sleeve 10, a holding means, as will be described below with reference to Fig. 9.

In the same axial position as the flange 34 there are two diametrically opposed guide lugs 35, which are arranged to cooperate in a slidable fashion with the upper axial slots 16 of the sleeve 10 with a view to holding the sleeve 10 and the rod 30 in a non-rotatable relationship.

From the flange 34 extends a straight cylindrical lower portion 36 of the rod to a lower end 39 of the rod.

In a lower area of the lower portion 36 there are four radially projecting stop lugs 41, which have upwardly directed abutment surfaces 32 to form stop means, in cooperation with the abutment surfaces 12 of the lower slots of the sleeve 10. The stop lugs 41 also serve to hold the sleeve and the rod in a non-rotatable relation- ship.

Fig. 8 illustrates the anchoring device in an assembled state and in a resting position A, i. e. a position in which the device is intended to be located when being inserted into a base. In the resting position, the rod 30 is partially inserted into the sleeve 10,

which is unexpanded and non-tensioned, and is prevented from being withdrawn by cooperation between the axial abutment surfaces 12,32 facing each other.

When mounting the anchoring device, the entire device is introduced into the base, preferably in a pre- drilled hole, in the direction of arrow C, which corre- sponds to the downward direction. The lower portion 28 of the sleeve 10 is radially compressed thanks to the clear- ance formed by the slots 15. A certain mutual resistance to axial displacement between the rod and the sleeve exists and is emphasised by the radial pressing in of the lower portion 28, and therefore the entire device can be moved downwards in an essentially unchanged relationship until the upper flange portion 23 of the sleeve, said flange portion serving as abutment means, comes into engagement with the base. This prevents the gripping sleeve 10 from being moved further down in the hole. Then the operating rod 30 is moved downwards relative to the sleeve to the position shown in Fig. 9. An operating means (not shown), for instance in the form of an annular tread flange of the slalom pole, can be connected to the operating rod to facilitate displacement of the operating rod relative to the gripping sleeve.

Fig. 9 shows the anchoring device in the gripping position B, in which the rod 30 is prevented from being moved further downwards (direction C) owing to the coope- ration between the opposing abutment surfaces 13,33. In the gripping position B, the lower straight portion of the rod abuts against the conical portion 11 of the sleeve 10, which means that the lower portion 28 of the sleeve 10 is radially expanded or extended. At the same time the conical portion 31 of the rod 30 abuts against the upper straight portion 26 of the sleeve 10, which results in a radial expansion of the upper portion 26 of the sleeve. For adequate anchoring, it is preferred that the lower portion be more expanded than the upper portion in the gripping position.

In the gripping position, the individual legs are movable to some extent, and therefore the anchoring device can, when affected from outside, for instance when being run into, in itself, i. e. in the legs, absorb late- ral forces. This reduces the influence on the hole.

As is evident from the Figure, the recess 14 coope- rates with the flange 34 as a snap lock in the gripping position to serve as holding means and hold the sleeve and the rod in an invariable axial relationship.

When the anchoring device is to be released from the base, it suffices to pull the slalom pole (not shown), which is connected to the rod 30, straight upwards (arrow D) by applying sufficient force to overcome the snap lock function of the holding means between the flange 34 and the recess 14. Then the rod 30 is moved upwards relative to the sleeve 10 to the resting position, whereupon the entire anchoring device can be removed from the hole.

The scope of protection of the invention is not limited to the embodiment shown.

The number of tapering portions for expanding the gripping sleeve is not limited to two. Nor need the tapering portions have a truncated conical shape.

Although, as described above, the anchoring device is preferably moved to the gripping position by a down- ward movement of the operating rod, it is also possible to use an inverse motion, in which case the tapering por- tion tapers off in the opposite direction.

The cross-section of the anchoring device need not be circular. It may in many contexts be advantageous to have other cross-sectional shapes, for instance to achieve a non-rotational connection between the rod and the sleeve and/or between the sleeve and the surrounding base.

The dimensional relationship in the circumferential direction between slots 15,16 and legs 8,7 can be dif- ferent. The slots can thus have a greater width in the circumferential direction than the intermediate legs.

The anchoring device can be a separate part to be connected to a slalom pole. Alternatively, the operating rod can in one piece consist_of the lower end of the slalom pole. Furthermore, the anchoring device is suited for all types of slalom poles, both poles with a hinge and poles with no hinge.