US 7,401,425 B2Granted

Snowthrower wheel drive steering system

AssigneeThe Toro Company

InventorsNathan J. Friberg, Donald M. White, III

Life of this patent

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Abstract

A snowthrower has independent wheel drive trains to allow steering by clutching one drive train while unclutching the other drive train. The clutch in each drive train comprises a plurality of pivotal pawls carried on a drive member with the pawls pivoting in a plane that is substantially perpendicular to the rotational axis of the drive member. The pawls have heads that project through one face of the drive member and tails located on an opposite face of the drive member. The heads of the pawls can engage or disengage notches that are fixed to the driven member to clutch or unclutch the drive and driven members. A shift member axially presses on the tails of the pawls to disengage the heads of the pawls from the driven member. The shift member is selectively moved by an operator using a steering lever on the snowthrower.

Claims29

Dependent claims

An improved snowthrower which is propelled by a pair of ground engaging drive members comprising a left ground engaging drive member and a right ground engaging drive member powered by a power source, the snowthrower having an upwardly and rearwardly extending handle assembly to allow a walking operator to guide and control the snowthrower, wherein the improvement relates to a steering system for the snowthrower which comprises:

(a) independent left and right drive trains for independently driving the left and right ground engaging drive members, respectively, from the power source, wherein each drive train comprises:
(i) a drive member rotatable about an axis of rotation;
(ii) a driven member rotatable about the axis of rotation;
(iii) a clutch having at least one pivotal pawl with the clutch configured to transmit torque from the drive member to the driven member directly through the pawl to transfer a driving force to one of the ground engaging drive members;
and
(iv) an axially movable shift member for pivoting the pawl as the shift member is moved axially along the axis of rotation;
and
(b) left and right steering controls carried on the handle assembly of the snowthrower and connected, respectively, to the clutches in the left and right drive trains to selectively disengage a ground engaging drive member on one side of the snowthrower to steer the snowthrower toward the one side of the snowthrower having the disengaged ground engaging drive member.

5 more elements

A snowthrower, which comprises:

a frame propelled by a pair of ground engaging drive members comprising a left ground engaging drive member and a right ground engaging drive member;
a rotatable snowthrowing member carried on the frame;
and
a steering system that includes a pair of clutches for independently driving the ground engaging drive members, wherein each clutch comprises:
(a) a drive member that rotates about a rotational axis;
(b) a driven member;
(c) at least one pawl carried on the drive member for operatively connecting the drive member to the driven member for rotation therewith in an engaged, drive position of the clutch, wherein the pawl pivots on a pivot axis carried on the drive member;
(d) a spring on the drive member acting on the pawl for pivoting the pawl in a first direction about the pivot axis;
and
(e) an axially movable shift member on the frame of the snowthrower, wherein the axially movable shift member acts on the pawl for pivoting the pawl against the bias of the spring in a second opposed direction about the pivot axis, and wherein the shift member is a shift collar that axially moves towards and away from the drive member along the rotational axis of the drive member.

7 more elements

A snowthrower, which comprises:

(a) a frame propelled by a pair of ground engaging drive members comprising a left ground engaging drive member and a right ground engaging drive member;
(b) a rotatable snowthrowing member carried on the frame;
and
(c) a steering system that includes a pair of clutches for independently driving the ground engaging drive members, wherein each clutch comprises:
(i) a toothed drive member that rotates about a rotational axis;
(ii) a toothed driven member that rotates about the rotational axis;
(iii) a plurality of pivotal pawls carried on the drive member, each pawl having a head and a tail on opposite sides of a pivot for each pawl with the heads of the pawls projecting from one face of the drive member to move towards or away from the driven member for engagement and disengagement with the driven member, respectively, the tails of the pawls being disposed on an opposite face of the drive member;
and
(iv) a shift member that moves axially along the rotational axis towards the opposite face of the drive member to simultaneously press inwardly on the tails of the pawls to pivot all the pawls on the drive member, the shift member being under the selective control of an operator of the snowthrower.

6 more elements

Dependencies are inferred from the claim text.

Facts

Application: 11/021,480Filed 23 Dec 2004
Published: US 2006/0150444 A113 Jul 2006
Granted: 22 Jul 2008
Term ends: Not estimatedThe source records don’t support an estimate.

Classification6 codes

E01H 5/04
Removing snow or ice from roads or like surfaces; Grading or roughening snow or ice: apparatus propelled by animal or engine power; Apparatus…
B62D 11/08
By means of a single main power source: using brakes or clutches as main steering-effecting means
B62D 51/001
Motor vehicles characterised by the driver not being seated: characterised by the vehicle control device
B62D 51/04
Motor vehicles characterised by the driver not being seated: the driver walking