This invention relates to an easily portable trail grooming device particularly designed for individual use, and for use with over-the-snow vehicles of low and medium horse power.
There are many situations where a pleasant ski slope can be made, or the bumps in a snow vehicle trail can be cut down if the groomer were small enough to be pulled by a low-powered vehicle. One can operate it easily, for it adjusts itself to snow conditions without the operator running back constantly to dump over-accumulations of snow, or raise the height of the groomer blades.
In my application, Ser. No. 269,077, filed simultaneously with this application, I disclosed a trail groomer characterized by a plurality of semi-circular grooming blades which successfully grooms the snow on trails usually opened for commercial purposes. The entire contents of the said application is incorporated herein by reference.
Since the purpose of the present invention is to produce a groomer which is light, portable, and capable of being carried to the ski slope or vehicle trail in the trunk of an automobile, the present groomer is designed to be easily disassembled and packed in the trunk space. More trips over the easily groomed area may be required to produce a satisfactory trail than does the groomer disclosed in the said companion application, but nevertheless, this small groomer will produce a trail which is comfortable and well cleared of moguls even when it is towed by a low-powered over-the-snow vehicle.
The device includes a centrally located beam, which conveniently may be galvanized pipe approximately 12 feet long, jointed so that it can be disassembled and transported in parts. A fixed shear for cutting down moguls is fastened to the forward section of the beam, and carries a downwardly projecting blade, while a curved blade which cuts, grooms, and also levels the snow, is fastened to oppositely directed struts extending outwardly and rearwardly from the fixed mogul shear.
The accompanying figures show the device:
FIG. 1 is a top plan view of the groomer,
FIG. 2 is a side view of the groomer with the blade in the position for maximum cut. The dotted lines on FIG. 2 show the position of the groomer blade and the mogul shear, when the blade has been lifted to its highest position and the beam-lifting shoe is at its maximum depressed position.
As shown in FIG. 1, the device, 10, comprises a beam, 11, preferably about 12 feet long. Beam, 11, may be sectionalized and joined by a suitable coupling or couplings as shown at 12 to make the device portable. A 1-inch steel pipe makes a satisfactory beam.
Opposite outward and rearwardly directed struts, 13 and 14, are rigidly fastened to the rigid shear, 15, the purpose of which is to cut down moguls. Shear, 15, is formed from a piece of angle iron with one arm, 16, bolted to beam, 11, and the other, 17, projecting downwardly to make a cutting blade.
Struts, 13 and 14, are wide and are twisted slightly so as to run against the snow with a slight angle of attack. The ends of struts, 13 and 14, are bent downwards at right angles to their plane in order to provide an attachment portion, 18, to which the tracking links, 19 and 21, are pivoted.
Side rails, 22 and 23, are pivoted adjacent the end of the tracking links at 24--24. An arcuate groomer and shearing blade, 25, is pivoted on the side rails, 22 and 23, at the pivots, 26--26. Solid blades can be used, but to reduce the weight of the groomer, blade, 25, can be formed of relatively thin-gaged hardened steel, reinforced however by an arcuate stiffening bar, 27, fastened to the thin blade in any appropriate manner as, e.g., spot welding.
The rear of the device is occupied by a lifting ski, 28, which has a ski-like shape flaring outward toward its rear end. A wedge or fin, 29, placed along the axis of ski, 28, rises steeply from the ski portion.
A draw-bar unit, 31, is mounted on the forward end of beam, 11, and is adapted to slide along the beam when pull is exerted through the chain bridle, 32, and the actual draw bar, 33. The lower portion of draw-bar unit, 31, is equipped with a rigid cam, 34, which can depress the lifting shoe, 35, as the draw-bar assembly is pulled forward. Lift shoe, 35, is fastened to the beam, 11, by pivot pin, 36, which passes through two ears, 37--37, formed on the shoe.
The upper rear portion of draw-bar unit, 31, carries a pull link, 38, to which it is fastened by pivot pin, 39. The rear end of pull link, 38, is pivoted on lever, 41, which in turn is pivoted on beam, 11, at 42.
A strong return spring, 43, stretched between the rear end of beam, 11, and lift ski, 28, normally pulls the lift ski into its maximum retracted position as shown in solid lines in FIG. 2. When, however, resistance to the forward motion of the groomer causes the return spring, 43, to stretch, wedge, 29, slides under blade, 25, and raises it as shown in dotted lines in FIG. 2. At the same time, the draw-bar unit, 31, is pulled toward the forward end of beam, 11, causing cam, 34, to depress the lift show, shoe, as shown in dotted lines in FIG. 2. The action of the lifting shoe, 35, lifts beam, 11, upward and reduces the depth to which the blade, 17, of the mogul shear is pushed into the snow. Since shear, 25, is also raised, the amount of snow which is cut and moved is automatically adjusted to the draw-bar effort of the towing vehicle.
This operation of lifting both the grooming blade and the mogul shear depends upon the adjustment of the tension exerted by return spring, 43. Proper tension is determined not only by the draw-bar pull of the towing vehicle, but by the snow conditions of the day. Setting the spring properly is accomplished by turning the threaded hand wheel, 44, which withdraws the eye bolt, 45, holding spring, 43.
In towing this device along a trail, one side is often higher than the other, and this is almost always the case when the trail rounds curves. Tracking links, 19 and 21, by hinging up and down, allow either end of the curved shear to ride in a plane above or below that occupied by the beam, 11. It is possible for this device which weighs but 87 lbs. to groom acceptably a wide 42-inch trail with a comparatively low-powered over-the-snow vehicle. The fact that it is self-adjusting to the load means that the operator does not have to stop the machine, jump off and adjust the shears to meet the snow conditions. He can continue on his machine and do an acceptable job. It entirely overcomes the chance of digging holes in the trail when the groomer is stuck and the treads of the towing vehicle continue to turn and dig.
Furthermore, the device is extremely stable as it is being towed due to the very wide struts, 13 and 14, which resist upset, and when they are bent with an upward cant will not dive under an icy crust, but rather ride up over it. In giving stability to the device, particularly in crusted snow, a wide flat strut is a great improvement. In the present example, the struts are 3 1/2 inches wide.