Excavating – Snow or ice removing or grooming by portable device – Motorized rotary excavating tool
Reexamination Certificate
1999-05-14
2001-04-10
Pezzuto, Robert E. (Department: 3671)
Excavating
Snow or ice removing or grooming by portable device
Motorized rotary excavating tool
Reexamination Certificate
active
06212799
ABSTRACT:
This invention relates to rotary apparatus. One example of such apparatus, to which the invention can be applied, is a snowblower of the kind in which a drum having an auger or spiral blade is supplied with rotary power. The drum gathers snow in at an open mouth of the apparatus, and trajects the snow to a discharge chute with enough energy that the snow is blown away from the apparatus. Snowblowers can be non-driven, whereby the snowblower has to be pushed along the ground, e.g by a person walking behind, or by a tractor; or the snowblower can be equipped with power means for driving the snowblower along the ground.
The invention is applicable also to other rotary machines and apparatus, as will be described.
BACKGROUND TO THE INVENTION
Gasoline-powered snowblowers are conventional, and well known. However, powering snowblowers by means of an electric motor, though not unknown, is not common. Electricity has not been accepted as a favoured means for driving the drum of a snowblower. The power required for a conventional snowblower configuration can be easily supplied from a small gasoline engine, whereas drawing that much power from electric batteries can require an inconveniently large outlay in batteries. Supplying that much power from the electric mains via an extension cord would not be convenient either.
On the other hand, electric power is favoured no less for snowblowers than for other appliances, for the usual benefits of electric power, i.e simplicity of structure, ruggedness, lack of service problems, quietness of running, efficiency, and so on.
The invention is aimed at enabling the benefits of electric power to be realised in a category of cases where electric power was hitherto considered inappropriate.
GENERAL FEATURES OF THE INVENTION
A rotary apparatus that embodies the invention preferably includes a rotary drum. The drum is configured as a hollow cylindrical tube. The motor lies at least partly inside the drum. Preferably, the configuration of the apparatus is such that, in an end-view of the apparatus, the drum totally circumscribes the whole structure of the motor (i.e circumscribes the housing or outer casing of the motor) in the radial sense. Preferably, also in the axial sense, the motor lies at least partly contained within the ends of the hollow interior of the drum.
The drum is drive-coupled to the rotor of the motor, and preferably the drum is driven to rotate by the motor-shaft in direct unison with the motor-shaft—direct unison, that is to say, in the sense that there are no chain-drives, gearboxes, or the like between the motor shaft and the drum.
The invention would not be applicable in such a case as a winch, for example, in which a as drum is driven by a motor, but in which a large or very large gear-ratio is applied between the motor-shaft and the drum.
The invention is advantageous when applied to rotary machines in which the functional rotating structure can be built upon a rotating drum. That is to say, in which the functional rotating structure can use the rotating drum mechanically, as a structural mounting platform. Thus, the snowblower appliance has converging spiral augers built upon a drum; a rotary broom appliance has brush-bristles built upon a drum; and an anti-personnel-land-mine clearing appliance has chains or the like built upon a drum, which flail the ground when the drum is rotated.
As will be described, the invention is further advantageous when applied to the category of rotary machine in which the functional elements of the rotary apparatus are disposed axially along the length of a drum. The invention especially favours the category of rotary machine in which the functional rotary elements of the machine are disposed in a more or less even distribution along the length of the drum, especially when the drum has considerable axial length. Again, it will be appreciated that the snowblower, broom, and mine-clearing appliances fall into this category.
The invention is advantageous when applied to rotary machines in which the speed desired of the functional rotating structure, i.e when the speed at which the rotating structure itself must rotate in order to perform its function, is matchable with the rotational speed of the motor. In the case of a winch or crane, as mentioned, the apparatus cannot function unless the drum is at a large gear-ratio relative to the motor shaft.
It is not necessary, in the invention, that the drum and the motor must rotate at a constant speed during operation. However, the invention is advantageously applicable in such cases. The invention is especially advantageous in those cases in which, if the load on the drum should vary, the designer seeks to vary the torque produced by the motor in order to maintain the drum at constant speed. This is a usual desideratum in machines such as snowblowers, brooms and mine-clearing apparatus.
The invention is not applicable when the rotary machine includes nothing like a hollow cylinder or drum having axial length—for example, most rotary pumps include nothing like a long hollow drum. Furthermore, there would be no functional advantage arising from configuring the rotor of a pump in the form of a hollow rotary drum. However, if a certain type of pump could be advantageously configured as a rotating drum, the invention might be applicable to that.
The invention is mainly applicable to rotary machines in which the rotor has (or can be adapted to have) the form of a hollow cylindrical drum, and the functional rotary structure of the machine is (or can be adapted to be) mechanically mounted on the outside of, and along the length of, the cylindrical drum
The rotary component of a machine that embodies the invention has been referred to as a hollow drum. It should not be construed as a limitation of the invention that the hollow drum must be right-cylindrical; however, in the machines described herein, the drums are right-cylindrical. (A right-cylinder is a cylinder of regular shape and having a constant diameter along its length.)
For the invention to be advantageous in a particular case, the motor has to be right shape. That is to say, the motor should be of complementary shape to the drum, whereby the motor can fit inside the drum. Thus, the motor should be drum shaped, i.e its shape should be characterised as a compact cylinder having axial length. Electric motors generally have this shape. Hydraulic motors also either have this shape, or can be configured in this shape. One type of prime mover that really does not lend itself to being configured to the sort of shape that would fit inside a hollow rotating drum is, of course, the internal combustion engine.
The mechanically-simple configuration of motor to which the invention mainly applies may be distinguished from a gasoline engine, in which the engine block itself is but one a component of many which are needed to complete the drive function, including fuel tank, exhaust system, clutch and gearbox, etc, etc.
The invention is described herein as it relates to electric drive-motors, but, as mentioned, some of the benefits of the invention apply also with other rotary prime movers, such as hydraulic drive-motors. The invention is applicable when the motor is configured basically as a solid, compact, cylindrical structure, the energy for the motor being supplied (from an energy source, such as a battery, mounted on the non-rotating part of the apparatus) via a simple wire or pipe. The invention is aimed at making it possible to apply such drive motors, with their many benefits, in the context of such rotary apparatus as snowblowers and the like.
In one form, the rotary apparatus is intended for use as an accessory to an electric tractor, to which the apparatus is hitched, and upon which the batteries needed to power the apparatus are carried. A vertical-engagement hitching system of the kind described in the patent publication WO-94/21106 (GINGERICH, September 1994) is then preferred. The invention can also be applied in the case where the rotary apparatus is self-contained, for example in a push-along or walk-b
Asquith Anthony
Gingerich Newton Roy
Anthony Asquith & Co.
Electric Tractor Corporation
Pezzuto Robert E.
LandOfFree
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