WO1981002391A1

WO1981002391A1 - Device for making skiing tracks

Info

Publication number: WO1981002391A1
Application number: PCT/FI1981/000015
Authority: WO
Inventors: M Konttinen
Original assignee: M Konttinen
Priority date: 1980-02-29
Filing date: 1981-02-27
Publication date: 1981-09-03
Also published as: FI66757B; FI800627A; FI66757C

Abstract

In the ski-trail plow there is a pair of trail skis (15, 32) and a central vee-shaped plow (16). To the front part of the frame (10) of the ski-trail plow are connected draw bars (12), by which the ski-trail plow is drawn with a snowmobile. The ski-trail plow also comprises levelling plow equipment (13, 19, 22, 27), whose operating height (h) can be adjusted by means of adjusting equipment (20, 26), and the ski-trail plow has trail skis (15) that can be adjusted by means of a particular mechanism (18, 29, 30, 31). The supporting arms (22) of the levelling plow equipment are, at their rear ends, articulatingly fastened to a snap-on coupling (27). The trail skis (15, 32) comprise an adjustable front part (15) installed between the guides (17) and fastened in association with the frame (10) of the ski-trail plow by means of a pivot pin (25).

Description

DEVICE FOR MAKING SKIING TRACKS

The present invention relates to a ski-trail plow comprising a frame section to which is connected a pair of trail skis side by side, and a vee-shaped plow or similar, installed essentially centrally in respect of said trail skis, and to whose front part are connected draw bars, by which the ski-trail plow is drawn. with a snowmobile or similar.

As known, a ski-trail plow is used for preparing new ski-tracks and for maintaining old ones. A ski-trail plow is commonly pulled by a snowmobile.

The general objective of the present invention is to provide such a ski-trail plow of improved functional characteristics and versatility, at the same time keeping the construction of the ski-track plow simple and reliable.

A specific objective of the invention is to provide such a ski-trail plow that better than before levels the unevennesses of the trail line and, if so required, brings new snow onto the trail. An objective of the invention is also to provide such a ski-trail plow with which it is possible to straighten inclined trail lines and to cut appropriately wide passages for the snow rings or snow disks of the ski poles. A specific objective of the invention is also to provide such a skitrail plow that can be adjusted and adapted to operate in varying conditions for instance so as to provide the ski-trail with a suitable inclination. An objective of the invention is also to provide such a ski-trail plow that is, when compared with known ski-trail plows, less apt to be broken when hitting such obstacles as for instance stones and stumps. An objective of the invention is to provide such a skitrail plow that can be made go in a small space for instance for transport, and which can rapidly be assembled for plowing work.

For attaining the objectives mentioned above and to be expressed later, the principal characteristic feature of the invention is that, on the both sides of the trail skis, the ski-trail plow comprises levelling plow equipment, whose operating height can individually be adjusted by means of adjusting equipment, and that the ski-trail plow has trail skis that can be adjusted by means of a particular mechanism.

The invention will now be described in detail, by way of examples only, with reference to the accompanying drawings, with no intention to restrict the invention to these details.

Fig. 1 is a plan view of a ski-trail plow in accordance with the invention.

Fig. 2 shows a side view of the ski-trail plow represented in Fig. 1.

Fig. 3 shows section view III-III in Fig. 1.

Figs 4A and 4B show a ski-trail plow in accordance with the invention, when adjusted to two operational modes which will be described below.

A ski-trail plow represented in the figures is coupled to a snowmobile with ring 12a of draw bar 12, at whose other end there is a safety string 21 which snaps off in case the ski-trail plow is stuck for instance to a stone or similar.

Levelling blades 13 of the ski-trail plow are fastened articulatingly to frame 10 by means of arms 22 and pivot pins 23. Levelling blades 13 are also supported by draw bars 12. The angle between the draw bars 12 and levelling blades 13 and thus the height difference h is adjusted by means of screw device 20,26. As the height H of draw bars 12 changes, the cutting depth h will also be changed. Height measurement H varies according to the movements of the snowmobile in the terrain. As shown in Figs 1 and 2, supporting arms 22 of levelling blades 13 are, at their rear ends, fastened articulatingly to the frame of the ski-trail plow by means of pins 27. As shown in Fig. 2, this articulating joint is brought about by installing pivot pins that are fastened to arms 22 to notches 28 of brackets 29. Thus a snap-on coupling is provided between the frame of the ski-trail plow and the levelling plow 13,22. Levelling blades 13 are also fastened articulatingly to the front ends of their supporting arms 22 by means of pins 24. Should blade 13 be stuck to a stone or similar, spring 19 of the blade yields and stretches and blade 13 is released from the obstacle. Levelling blades 13 can also be turned off altogether.

The height of levelling blades 13 can be individually adjusted by screw devices 20 in such a way that the trails can be made inclined for instance in bends. In addition, screw device 20 is designed in such a way that it does not provide a fixed connection between draw bars 12 and supporting arms 22; instead, as draw bars 12 are turned upwards in the vertical plane, the draw bars will, at a certain point, meet the pins of screw devices 20, and only then supporting arms 22 of levelling blades 13 start to turn upwards along with the draw bars. As each supporting arm 20 has a separate screw device 20 of its own, it is possible to adjust each levelling blade 13 individually. The screw devices also ensure that supporting arms 22 together with levelling blades 13 and draw bars 12 can individually be detached from frame section 10 for instance for transport of the ski-trail plow. In the rear ends of supporting arms 22 there are snap-on devices 27 in the same way as there are snap-on devices 23 in the rear ends of draw bars 12, by means of which snap-on devices supporting arms 22 and draw bars 12 can rapidly be separated from frame section 10, and reinstalled when starting the plowing work.

The function of levelling blades 13 is to level unevennesses of the ski-trail line, bring new snow onto the trail in order to prevent the trail from being cut too deep and- to prevent icyness, straighten inclined trail lines (an inclined area is straightened by adjusting one of blades 13 to cut more deeply), and cut the space for snow rings or snow disks to an appropriate width and to a suitable height. New snow brought onto the trail covers the debris that falls onto the trail from trees. The ski-trail plow also comprises a vee-shaped plow 16 that is narrower than the levelling blades (b < B) (Fig. 1); the snow plowed aside by the vee-shaped plow is consequently returned for reuse during the following run with the advantage that the quantity of snow on the trail will not be diminished due to plowing. If there is plenty of debris on the trail, the trail is cut and run with such a speed that vee-shaped plow 16 throws the debris outside the trail line, the levelling blades 13 being in the raised position.

The ski-trail plow comprises trail skis 15, at their front edge articulatingly fastened to frame 10 by pivot pin 25. The position of trail skis 15 can be adjusted by linkage 18,29 depending on how much one wishes to cut the trail with cutting edges 14. Trail skis 15 can also be installed with spring loading.

As described above, the trail skis can be adjusted to various operational modes. Fig. 4A illustrates the trail skis in position 15a. In this case the track is not at all cut with blades 14, as trail ski 15a is at the same level with the bottom edge of blade 14. In Fig. 4B, the trail ski is in position 15b, adjusted with linkage 18,29. Now blades 14 reach below the level of trail skis 15b, and the trail is cut by blades 14. On both sides of trail skis 15, which are of constant width but otherwise like the bow of an ordinary ski, there are two for instance plate-shaped guides 17 directly located on both sides of trail ski 15. Guides 17 reach below frame 10, and, at least partially, provide the ski-trail plow with lateral control. After blades 14 there are ski parts 32, of the shape of an opened U, which compact the ski-trail cut by blades 14 and prevent the trail from being filled up during plowing.

The lever mechanism by means of which trail skis 15 are adjusted to different functional modes comprises a horizontal arm 31 connected to trail_^ skis 15 with brackets and a lever arm 18 fastened articulatingly in the middle of the horizontal arm 31. Lever arm 18 is in connection with another lever arm 29 fitted with a notch, into which a wing screw 30 is installed for locking lever arms 18 and 19 to different positions and consequently for adjusting the operational position of trail ski 15 for instance as illustrated in Figs 4A and 4B or between the positions illustrated in Figs 4A and 4B.

The function and operation of the trail ski equipment is as follows. The snow plowed onto the trail by levelling blades is compacted by trail skis 15. The adjustment of the trail skis should preferably be continuous. The position of trail skis 15 is as illustrated in Fig. 4A during transport, in a steep uphill in which no trail rut is required, and when a trail is made by sufficiently compacting soft snow on the trail of when making a new trail into virgin snow.

The position of trail skis illustrated in Fig. 4B is used when cutting a trail rut into hard snow. Now trail ski 15b is adjusted to the same level with the frame, and, according to the softness of the snow, the ski is adjusted to an appropriate level. At both sides of trail skis 15 there are guides 17 (Fig. 2), whose function is to maintain the direction of the ski-trail plow stabile and to prevent lateral skidding, to protect the trail-rut cutting blades and to prevent the trail-rut cutting blades from sticking to stones, branches or similar obstacles. The function of cutting blades 14 is to cut trail ruts into the proper shape. The bottom and edges of the trail ruts are cut by blades 14. The shape of cutting blades 14 is illustrated in Fig. 3.

The invention is by no means restricted to aforementioned details which are described only as examples; they may vary within the framework of the inventional idea as defined in the following claims.

Claims

1. A ski-trail plow comprising a frame section (10) to which is connected a pair of trail skis (15,32) side by side, and a veeshaped plow (16) or similar, installed essentially centrally in respect of said trail skis, and to whose front part are connected draw bars (12 ), by which the ski-trail plow is drawn with a snowmobile or similar, wherein on both sides of the trail skis (15,32), the ski-trail plow comprises levelling plow equipment (13,19,22,27), whose operating height (h) can individually be adjusted by means of adjusting equipment (20,26), and that the ski-trail plow has trail skis (15) that can be adjusted by means of a particular mechanism (18,29,30,31).

2. A ski-trail plow in accordance with claim 1, wherein the supporting arms (22 ) of the levelling plow equipment are, at their rear ends, articulatingly and with snap-on couplings fastened to the frame section (10) of the ski-trail plow.

3. A ski-trail plow in accordance with claim 1 or 2, wherein the draw bars (12 ) of the ski-trail plow are articulatingly and with snap-on couplings (23 ) fastened to the front part of the frame (10 ) of the ski-trail plow.

4. A ski-trail plow in accordance with claim 1,2 or 3, wherein between the draw bars (12 ) of the ski-trail plow and the draw ring (12a) or similar there is a safety item, for instance a coupling composed of a safety string (21 ).

5. A ski-trail plow in accordance with one of claims 1 to 4, wherein the levelling blades located on both sides of the trail plow are fastened to their supporting arms (22 ) by means of an essentially horizontal joint (24 ) and fitted with spring devices (19 ) that allow the levelling blades to turn when hitting obstacles.

6. A ski-trail plow in accordance with one of claims 1 to 5, wherein the supporting arms (22) of the levelling blades (13) are, by means of an adjusting device (20,26), connected to draw bars (12) in such a way that each levelling plow device (13,22) can individually be adjusted in the vertical direction.

7. A ski-trail plow in accordance with one of claims 1 to 6, wherein the trail skis (15,32) comprise an adjustable front part (15) installed between the guides (17) and, at the front end, fastened in association with the frame (10) of the ski-trail plow for instance by means of a pivot pin (25) .

8. A ski-trail plow in accordance with claim 7, wherein behind said adjustable trail skis (15) there are cutting blades (14) for cutting trail ruts, behind which cutting blades (14) there are fixed trail skis (35) of the shape of an ϋ opening upwards.

9. A ski-trail plow in accordance with claim 7 or 8, wherein the adjusting equipment of the trail skis (15) comprise an arm (31) connecting the trail skis (15) with each other, said arm (31) being connected to a mechanism (18,29), by means of which the trail skis (15) can be adjusted to various operational positions.

10. A ski-trail plow in accordance with one of claims 1 to 8, wherein the levelling blades (13) of the levelling plow equipment are so installed as to plow snow toward the running trail of the trail skis (15,32).