Drag Roller

Abstract

A drag roller, especially for grading or levelling ski pistes, with a roller body rotatably supported upon an axle. The axle is composed of a number of partial axle components which are coupled with one another by joints having 1.degree. of freedom of movement, the pivot axes of which extend approximately parallel to the direction of travel. At least a number of the partial axle components each carry a respective roller body. The end face of one of two neighboring roller bodies is formed by a substantially ball or spherical head which merges with the outer surface of such roller body, and this ball head engages with the neighboring roller body which is constructed at its neighboring end face in the manner of a ball socket.

Description

BACKGROUND OF THE INVENTION

The present invention relates to a new and improved construction of drag roller or roll, especially for levelling or smoothing ski pistes, by means of a roller body rotatably mounted upon an axle or shaft.

Drag rolls for levelling or smoothing ski pistes have been utilized for quite some time, and generally are suspended at a snow vehicle equipped with crawler tracks. A state-of-the-art construction of drag roll contemplates rotatably mounting the roller body in a frame, the width of the roller corresponding approximately to the working width or gauge of the crawler tracks.

Economical tending or servicing of the ski pistes continually requires larger working widths of the crawler track vehicles, wherefore the grading or levelling drag rollers also increase in width. On the other hand, it has been found that the actual levelling or smoothing action of the prior art drag rollers tends to decrease as the width thereof increases, although increasing such width is accompanied by an increase in weight. This is predicated upon the fact that the transverse profile of the base surface or stratum with working widths which exceed about 2 meters -- notwithstanding the smoothing action of the layer of snow -- for the most part has portions of the terrain which are to be treated exhibiting considerable irregularities. This in effect means that the drag roll only bears with one portion -- oftentimes a rather insignificant portion -- of its width upon the blanket of snow.

Hence, in an attempt to overcome this unsatisfactory operation of the equipment, proposals have been made to level the working width of the traction vehicle by using a number of smaller rolls which are divided over the width and which are movable independently of one another.

According to a know arrangement in the art which is equipped with a number of drag rolls, there are symmetrically arranged in the direction of travel of the vehicle, two further rollers behind a first roller which is guided approximately centrally of the vehicle. Although the operable working zone of the individual rollers in their width joins one another without any intermediate space or gap, or in fact even overlaps, the edges of the rear rollers have been found to form tracks or grooves in the processed ski piste. Since these tracks or grooves are formed by compacted snow, they constitute disturbing irregularities for the skier and form a potential source of danger as concers ski accidents.

SUMMARY OF THE INVENTION

Hence, it should be recognized from what has been discussed above, that this particular field of technology is still in need of an improved construction of drag roll for the treatment of ski pistes which is not associated with the aforementioned drawbacks and limitations of the prior art constructions. Therefore, it is a primary object of the present invention to provide a drag roll construction which satisfies the needs still existing in the art and is not associated with the aforementioned drawbacks and limitations of the prior art proposals.

Another and more specific object of the present invention relates to a new and improved construction of drag roll which is capable of accommodating itself to the transverse profile of the terrain and nonetheless can level or smooth the skiing piste without the formation of the undesirable stepped portions or irregularities across the working width of the traction vehicle.

Yet a further significant object of the present invention relates to a new and improved construction of drag roller arrangement for use at a vehicle for the treatment of ski pistes which is relatively simple in construction and design, economical to manufacture, extremely reliable in operation, and versatile in use in that it can adapt itself during use to different encountered transverse profiles of the terrain over which it travels.

Now in order to implement these and still further objects of the invention, which will become more readily apparent as the description proceeds, the new and improved construction of drag roll of this development contemplates that the axle is composed of a number of partial axle components or members which are coupled with one another by joints having one degree of freedom of movement, the pivot axes of which extend approximately parallel to the direction of travel. Further at least a portion of the partial axle components each carry a roller body. The end face of one of two neighboring roller bodies is formed by a ball head which merges with the outer or jacket surface thereof and this ball head engages with the end face of the neighboring roller body which is constructed in the form of a ball socket.

Due to this construction of drag roller, which is believed to be unique in the art, it is possible to level or grade the snow surface during a single pass of the traction vehicle dragging such roller over the effective working width thereof. Moreover, due to the interengagement of the individual roller bodies, there is advantageously avoided the formation of the aforementioned undesired tracks, and owing to the coherency of the roller bodies by means of their partial axle components, there are also smoothed the steps in the transverse profile of the terrain which are formed during travel of the crawler track vehicle.

BRIEF DESCRIPTION OF THE DRAWING

The invention will be better understood and objects other than those set forth above, will become apparent when consideration is given to the following detailed description thereof. Such description makes reference to the annexed drawing wherein:

FIG. 1 schematically illustrates a preferred constructional embodiment of drag roller designed according to the teachings of this invention, partially in elevation, and partially in axial sectional view:

FIG. 2 is a top plan view of the drag roller or roll depicted in FIG. 1:

FIG. 3 is an enlarged detail sectional view of embodiments drag roller: and

FIG. 4 is a further enlarged detailed sectional view of a different portion of such drag roller.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

Describing now the drawing, in FIGS. 1 and 2 reference character 2 designates a substantially rectangular-shaped frame which carries at its narrow sides 4 extending in the direction of travel a respective bearing body 6. The frame beam 8 which leads in the direction of roller travel carries at its central portion a frame-like headpiece or member 10 in which extends a pivot journal or pin 12 parallel to the narrow sides 4 of the frame 2. A coupling element 14 is seated upon the pivot pin 12 and is connected therewith through the agency of a conventional Neidhart spring. The coupling element 14 serves as a convenient connection means with the end of a non-illustrated crane-like beam or overhang which is secured to the traction vehicle and is directed rearwardly with regard to the direction of travel thereof. The expression "traction vehicle" is intended to mean a vehicle, such as a crawler track snow vehicle, to which the drag roller is secured for dragging same.

Each of both bearing bodies 6 contains a crosspiece 16 which engages by means of pivot pins 18 in bearing sleeves or bushings 20. The crosspiece 16 is pivotable in the bearing sleeves or bushings 20 secured to the associated bearing body 6 about an axis which extends essentially parallel to the pivot pin 12 and the narrow sides 4 of the frame 2. Each crosspiece 16 contains a bore 22 which extends perpendicular to the pivot pins 18, bore 22 receiving the free end of an associated outer situated partial axle component 24.

Between both of the outermost situated partial axle components 24 there is disposed an intermediate partial axle component 26 which is connected with each neighboring end of the associated one of the outer situated partial axle component 24 by means of a respective joint or hinge arrangement 28 having one degree of freedom of movement. The partial axle components 24 are displaceable in the bores 22 and can be secured against rotation, by any suitable and therefore not particularly illustrated means, in a position in which the pivot axes of the joints 28 of one degree of freedom of movement extend parallel to the pivot pins 18.

The partial axle components 24 and 26 are of hollow design. The partial axle components 24 each contain a substantially cylindrical-shaped intermediate portion 30 which, in turn, closes a fluid cylinder 32 secured therein. In the fluid cylinder 32, there is displaceably arranged an actuation piston member 34, the piston rod 36 of which is coupled with a locking bolt 38, as best seen by referring to FIGS. 1 and 4. Opposite faces of the piston 34 can be impinged with a pressurized fluid medium, such as pressurized oil, by means of lines or conduits 40 and 42 which are connected with the cylinder 32, so that the locking bolts 38 can be displaced out of the retracted position depicted in FIG. 1 and shifted into the locking bolt 38 which is displaceably guided in the end of the associated partial axle component 24 connected with the joint 28 having a single degree of freedom carries at its free end a conically tapered portion 39. In the locked position, the locking bolt 38 also extends into the neighboring hollow partial axle component 26 and thus froms a connection, which is rigid against bending, between both of the partial axle components 24 and 26: the joint 28 therefore becomes ineffectual. In the retracted position of the locking bolt 38, the conically tapered portion or end 39 just extends into the partial axle component 26, so that the joint 28 has free single freedom of movement.

Although with the illustrated exemplary embodiment, the angle through which the partial axle components 24 and 26 can pivot to both sides out of the coaxial position is limited by the conical tapered portion 39, it would be also conceivable to provide stops at the cooperating components of the single freedom of movements joint which limit the maximum angling or deflection. In the illustration of FIG. 1, both of the partial axle components 24 and 26 are depicted in the position of maximum deflection or angling: a pronounced deflection is prevented because the conically tapered portion 39 of the locking bolt 38 bears against the inner wall of the neighboring partial axle component 26.

Each partial axle component 24 and 26 carries a roller body 44 and 46 respectively, wherein such roller bodies are provided with a suitable contour or profile, and are supported through the agency of bearing sleeves or bushings 48 rotatably upon the associated partial axle component. The bushings 48, which are secured at the roller bodies, cooperate with non-illustrated stop shoulders at the partial axle components in order to prevent axial displacement of the associated roller body.

As will be best seen by referring to FIG. 1, the ends or end faces of the roller body 46 are formed by substantially ball or spherical heads 52 (only one of which is shown in the drawing) which directly merge with the outer surface or jacket 50 thereof, and wherein the center point of the radius thereof is located at the pivot axis of the neighboring joint 28. On the other hand, the end faces of the roller bodies 44 which confront the roller body 46 forms recesses or depressions 54 in the manner of ball sockets, the radius center point of which again is located at the pivot axis of the neighboring joint 28, wherein the radius thereof is greater by a small amount from that of the ball head. However, the difference in radius is chosen to be just so great that the required movement play for the pivoting of the partial axle components 24 and 26 with regard to one another as well as possible rotation of the roller bodies 44 and 46 with different peripheral speeds is insured for.

If the drag roller is employed for levelling or grading a ski piste, then it is connected by means of the coupling element 14 at an elevationally displaceable overhang or beam of the traction vehicle, which, as a general rule, is a crawler track vehicle, and the coupling element possesses nonillustrated locking means of any suitable design. Both of the conduits or lines 40 and 42, which can be constructed as flexible hoses, are coupled with an oil pump and a control device which is provided at the traction vehicle, preferably capable of actuation from the driver's cabin. If a terrain is to be treated which in transverse profile is completely level, then the control device can be actuated such that both of the locking bolts 38 are shifted by means of the associated piston 34 so as to assume their locked position depicted in FIG. 4. As a result, the drag roll behaves in the manner of a rigid roller construction. This type of mode of operation of the equipment is especially possible in the case of a levelled surface, as such would be found for instance at the run-out regions of ski jumps and ski pistes.

On the other hand, if the transverse profile of the piste to be levelled is irregular or uneven, then such is processed with the locking bolts 38 located in retracted position, so that the individual roller bodies can accommodate themselves to the transverse profile of the terrain. Hence, if at one side of the roller or at the region of one roller there is present a greater contact pressure than at the other roller bodies, then this roller will upwardly deflect or deviate since the partial axle components are pivotably connected with one another, and wherein at the same time both of the crosspieces will accommodate themselves to the new position of the partial axle components 24. If the irregularities at the terrain are in the form of bumps or moguls which extend in the lengthwise profile thereof, then when such exceed a certain magnitude, the frame 2 will also be pivoted or rocked about the pin 12 extending in the direction of travel of the vehicle and the drag roller and against the action of the Neidhart spring means, wherein the pre-biased Neidhart spring means will insure that the roller body will be thereby guided at the run-off side of the mogul in such a manner that the frame will again return back to its starting position. In FIG. 1 the frame is shown in a deflected position, as such would arise when tavelling over moguis which exceed a certain height.

Whereas the roller bodies are conjointly axially displaceable by means of their partial axle components in the bores 22 of the crosspieces 16, the partial axle components 24 carry at their free ends impact or stop rings 56 which limit the axial displacement upon contact with the crosspieces 16. Due to the axial displaceability of the partial axial components in the cross pieces 16, there is simultaneously insured that there can occur the displacement at the crosspieces 16 which is necessary during their angling or deflection.

Instead of mounting the crosspieces 16 in housing or bearing bodies 6 which are rigidly connected with the frame, it would also be possible to suspend such at guides connected with the frame and which are pivotable about shafts extending in the direction of travel. The guides could then be connected with the frame again by Neidhart springs in order to retain such in a preferred direction of extent. The guides can also extend in the rest position, for instance at an angle of 45.degree. with regard to the outer roller bodies a more pronounced deflection, without necessarily having to pivot the frame about the pivot 12.

A similar mode of operation could also be attained if, for instance, the partial axle components 24 themselves were not articulated at the crosspieces 16, rather shorter auxiliary pieces which likewise would be connected with the partial axle, components 24 through the agency of joints 28 having a single freedom of movement. Finally, it also would be possible to arrange the crosspieces 16 displaceably in the housing body 6 in order to insure for a greater freedom of angling or deflection of the outer roller bodies 44.

Although in the illustrated exemplary embodiment all of the joint axes as well as also the pivot axes of the crosspieces and the frame extend in the direction of travel and are parallel to one another, the axes of the crosspieces could enclose a slight angle with respect to the plane of the frame 2, whereby the pivot axes of all single degree of freedom of movement joints 28 would extend parallel to the axes of the crosspieces. This arrangement would facilitate the deflection of the roller bodies relative to one another upon travelling over moguls and, if desired, would render possible a more rapid accommodation of their position to the change in the shape of the terrain.

While there is shown and described present preferred embodiment of the invention, it is to be distinctly understood that the invention is not limited thereto, but may be otherwise variously embodied and practiced within the scope of the following claims. Accordingly,

Claims

1. A drag roll arrangement especially for levelling ski pistes, comprising an axle consisting of a number of partial axle components, a respective joint having a single degree of freedom of movement for interconnecting neighboring partial axle components with one another, each said joint having a pivot axis which extends substantially parallel to the direction of travel of the drag roll arrangement, and at least a portion of the partial axle components each carrying a roller body, the end face of one of two neighboring roller bodies being formed by a substantially ball-like head which merges with the outer surface thereof, and the neighboring roller body being provided at its end face confronting the end face of the other roller body with a ball socket, said ball-like head engaging with

2. The drag roller arrangement as defined in claim 1, wherein three roller

3. The drag roller arrangement as defined in claim 2, wherein each of the

4. The drag roller arrangement as defined in claim 3, wherein a respective further free partial axle component merges at each side with the partial

5. The drag roll arrangement as defined in claim 1, wherein the outermost partial axle components are provided with means for mounting each of the same to be axially displaceable at a drag frame and pivotably about an axis extending substantially parallel to the direction of travel of the

6. The drag roll arrangement as defined in claim 5, wherein the drag frame possesses a substantially rectangular configuration and carries a coupling member which is pivotably mounted about an axis extending approximately

7. The drag roll arrangement as defined in claim 1, wherein the partial axle components incorporate locking means in order to block the associated joints in a predetermined position, and means for actuating the locking

8. The drag roll arrangement as defined in claim 7, wherein the partial axle components are at least partially hollow, and the locking means incorporates a locking bolt displaceably guided in one of two neighboring hollow partial axle components, and said actuating means comprises a fluid-actuated cylinder containing a piston therein, said piston being operatively connected with the locking bolt.