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Publication numberUS3692132 A
Publication typeGrant
Publication dateSep 19, 1972
Filing dateApr 26, 1971
Priority dateApr 27, 1970
Also published asCA934794A1
Publication numberUS 3692132 A, US 3692132A, US-A-3692132, US3692132 A, US3692132A
InventorsPollanen Kyosti Johannes
Original AssigneeVelsa Oy
Export CitationBiBTeX, EndNote, RefMan
External Links: USPTO, USPTO Assignment, Espacenet
Improved motor sledge
US 3692132 A
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Description  (OCR text may contain errors)

United States Patent Pollanen [54] IMPROVED MOTOR SLEDGE Kyosti Johannes Pollanen, Isokyla,

[72] Inventor:

Finland [73] Assignee: Velsa 0y, Kurikka, Finland [22] Filed: April 26, 1971 [21] Appl. No.: 137,477

[30] Foreign Application Priority Data April 27, 1970 Finland ..l 168 [52] US. Cl ..,..l80/5 R, 180/954, 305/20, l 305/27 [51] Int. Cl ..B62m 27/02, B62d 55/16 [58] Field of Search....305/20, 27, 10; 180/924, 9.2, 180/954, 9.32

[56] References Cited UNITED STATES PATENTS 3,157,913 11/1964 Habert .L' "ISO/9.24 R

[ Sept. 19, 1972 3,447,621 6/1969 Schoonover ..l80/9.64 R

FOREIGN PATENTS OR APPLICATIONS 842,862 3/1939 France ..305/22 Primary Examiner-Richard J. Johnson Attorney-Albert M. Parker 57 ABSTRACT ln a motor sledge having a supplementary frame extending from the rear end of the frame construction and flexibly pivoting around a horizontal axis the slackening of the common drive belts due to upward movement of the supplementary frame is prevented by a pair of rolls freely rotatable above the point of pivotement. When the supplementary frame pivots upwardly the upper surface of the drive belts are pressed against the rolls.

2 Claims, 3 Drawing Figures PATENTEDszmmz 3,692 132 SHEEI 3 0F 3 r W (mm a! BACKGROUND OF THE INVENTION 1. Field of the Invention The invention relates to the field of motor sledges having a supplementary frame.

2. Description of the Prior Art The disadvantage of fixed frame extensions is that on rough ground the front part of the sledge tends to dive into the slop when going uphill. Also, the steerability of a sledge with such a fixed extension frame is not good owing to the length and stiffness of the frame. In spite of the lengthened drive belt the pulling efficiency is not entirely desirable, since on uneven ground each part of the roller belt will not touch the ground with the same surface pressure. On hard, rough ground the long stiff frame has tended to brake under a slightly heavy driver. Furthermore, the desired decrease of the surface pressure of the roller belt against the ground has not been obtained in spite of the longer bearing surface, since it' has been necessary to support the extension frame with many kinds of supporting structures to reinforce the joint, and these structures have added to theweight of the extension part.

There are also different previously known snowvehicles in which the drive belt has been fitted around sprung roller wheels. It has been noted, however, that the part of the belt above the wheels in these known structures will slacken, in which case the grip between r the roller belt and the wheels weakens decisively.

SUMMARY OF THE INVENTION According to the invention there is provided an improved motor sledge having a hinged frame extension and limiting organs fitted against the upper surface of the drive belt and attached to the frameapproximately above the joint to prevent the drive belt from slackening at depressions, when the rear end of the frame extension rises.

It is advantageous if the limiting organs are two wheels rotating freely on each side of the frame around the same horizontal axis.

The frame extension according to the invention together with the original sledge form .one entity which follows the ground. Even at abrupt depressions the front part of the sledge rises easily uphill. The steerability of such a sledge is also good since, when tilted, the flexible frame tends to assimilate to the sharpness of the curve. As the frame follows the ground, the entire length of the lengthened drive belt gets a good grip of the ground and the pulling efficiencyis good in all positions because of the limiting organs. This is also why the sledge runs very well in soft snow, which was particularly noticeable in steep uphill tests in which it was compared with fixed frame extensions. Because of the ladder structure, the hinging, and the springing, a frame extension according to the invention can be constructed with small material thickness without decreasing the durability. In this case the weight of the frame extension remains as small as possible and the surface pressure of the lengthened drive belt considerably smaller than that in the previously known solutions.

DESCRIPTION OF THE DRAWINGS FIG. 1 shows a perspective view of the frame extension,

2 FIG. 2 shows the mounting scheme for the same frame-extension, and

FIG. 3 shows a motor sledge according to the invention at difl'erent ground positions.

DESCRIPTION OF THE PREF ERRED EMBODIMENT cording to the drawing, with the extension frame is attached to the sledge frame by screws, have beenfattached to the same axle by branch cotters. One set of wheels 6 has been attached by screws 5 to lobes 4. The frame extension has been fittedl at the axle of the wheels by spiral springs 7 provided with 'pins to the lobes welded to the lift bow of the sledge. The back axle wheels 8 have been sprung with swinging arms 9 and attached to the frame shafts by extensions 10 fitted inside the shaft. The ends of the axle of the limiting rolls ll of the drive belt have been attached by screws at the hinging of the frame extension to the frame of the sledge above the drive belt. The limiting rolls prevent, I

tension to its lowest position. The stiffness of the flexibility can be easily regulated according to the ground, r

the snow conditions, and the weight of the driver or the load to be carried by control plates to be added to the ends of the spiral springs.

When a frame longer than the frame extension according to the invention is desired, it can be obtained a by extending the frame shafts to correspond with the desired number of wheels.

The frame extension can be hinged to the sledge, frame even without the attachment pieces 3 that elevate the frame. In this case the ability of the frame extension to bend upwards, however, decreases when the inner space of the frame lowers. The frame extension can also be hinged to a separate axle behind the hindmost roller wheelsof the sledge.

With different applications an extension according to the invention suits most known sledge brands in which the motor is in the front of the sledge. A frame extension according to the invention can also be fitted to motor sledges with two belts.

What is claimed is:

1. An improved motor sledge of the type having a rigid frame construction; steering means attached to the front part of the frame construction for pivotable movement around a substantially vertical axis; a plurality of wheels rotatably mounted under the frame construction; a supplementary frame portion attached to the rear end of the frame construction for flexible pivotable movement around a horizontal axis therein and further provided with wheels; at least one common endless drive belt fitted around the wheels; a power 3 source fixed to the frame construction; and power ing.

2. The improved motor sledgeof claim 1, in which the means for preventing slackening of the drive belt comprise a pair of coaxial rolls rotatably mounted on opposite sides of the frame construction for preventing a pair of drive belts from slackening.

wards in order to prevent the drive belt from slacken-

Referenced by
Citing PatentFiling datePublication dateApplicantTitle
US3788412 *May 17, 1972Jan 29, 1974Coleman CoSnowmobile suspension system
US3830323 *Aug 1, 1972Aug 20, 1974Polar Metal PlastMotor sleigh drive track arrangement
US5062493 *Jul 19, 1990Nov 5, 1991Leitner, S.P.A.Tracked vehicle and in particular one for the preparation of ski slopes
US6435290Dec 20, 2000Aug 20, 2002Mmmj Inc.Personal tracked vehicle
US6510913Feb 11, 2000Jan 28, 2003Bombardier Inc.Long track mountain snowmobile and a track therefor
US6609771Sep 30, 2002Aug 26, 2003Bombardier Inc.Long track mountain snowmobile and a track therefor
US6772852Sep 30, 2002Aug 10, 2004Bombardier Recreational Products Inc.Long track mountain snowmobile and a track therefor
US7083241 *Jul 9, 2004Aug 1, 2006Gunter Herbert DTrack tensioner for a wheel-driven skid steer
US7464997 *Aug 2, 2005Dec 16, 2008Raytheon CompanyLoad bearing crawler assembly
US7740094May 23, 2008Jun 22, 2010Rolic Invest S.A.R.L.Snow groomer
US7802645 *Aug 24, 2007Sep 28, 2010Bombardier Recreational Products Inc.Articulated suspension assembly for a tracked vehicle
US8307573Oct 29, 2008Nov 13, 2012Rolic Invest S.A.R.L.Rotary snow tiller for grooming ski slopes
US8387288Oct 29, 2008Mar 5, 2013Rolic Invest S.Ar.L.Rotary snow tiller for grooming ski slopes
US8388072Jun 20, 2008Mar 5, 2013Rolic Invest S.Ar.L.Crawler vehicle track grouser
US8393095Oct 29, 2008Mar 12, 2013Rolic Invest S.AR. L.Rotary snow tiller and ski slope grooming method
US8413353Oct 29, 2008Apr 9, 2013Rolic Invest S.Ar.L.Hitch device for connecting a groomer vehicle and a ski slope snow grooming implement, and control method employing such a hitch device
US8701312Mar 11, 2013Apr 22, 2014Snowgrolic S.Ar.L.Hitch device for connecting a groomer vehicle and a ski slope snow grooming implement, and control method employing such a hitch device
WO2001058744A1 *Feb 11, 2000Aug 10, 2001Morin DenisA long track mountain snowmobile and a track therefor
U.S. Classification180/193, 305/131, 305/20
International ClassificationB62D55/108, B62D55/104
Cooperative ClassificationB62D55/108
European ClassificationB62D55/108