Abrasive tool making process – material – or composition – With carbohydrate or reaction product thereof
Patent
1991-10-18
1993-10-12
Parker, Roscoe V.
Abrasive tool making process, material, or composition
With carbohydrate or reaction product thereof
277134, B24B 2300, F16C 3374
Patent
active
052514064
DESCRIPTION:
BRIEF SUMMARY
BACKGROUND OF THE INVENTION
The invention relates to a power hand tool of the type employing sealing washers at the output and drive shafts.
An electric tool of this type is well known from GM 79 31 401. Its gearbox casing walls are equipped with openings which are penetrated by output and drive shafts, and which are sealed against lubricant leakage by means of axial seals.
In comparison with solutions employed up to now, the use of these axial seals achieves better sealing results, but also leads to a considerable increase in the cost of the machine. The cause of this is that it is expensive to produce the necessary low surface roughness of the counter slide way of the axial seals, and their higher cost in comparison with the sealing washers used before.
SUMMARY OF THE INVENTION
The object of the invention is to provide a power hand tool in contrast to the conventional power hand tools, that can be more effectively sealed without change or with very little change to expenditure on manufacture and the costs of the individual parts, using, for example, felt sealing washers which have been normally used up to now. The seal has a longer life than the well known axial seals. By this means, lubricants with a lower viscosity than those usable up to this time can be used for the power hand tool of this invention.
This increases the life of the gears and the motors. Moreover, the requirement for driving energy is lower. The efficiency of power hand tools in accordance with this invention, extremely important for battery-powered models, increases markedly. Additional features of the invention include the sealing washer being bonded with the hub, or the hub which consists of liquefiable synthetics being diffused into this sealing washer, starting at the inner circumference of the ring-shaped sealing washer. The advantage of it is that forces applied to the sealing surfaces of the sealing washer can neither push the hub and sealing washer against one another nor separate them from one another. Also the press fit of the hub, and thus the sealing washer, on the shaft is very secure.
The present invention both as to its construction and to its mode of operation, together with additional objects and advantages thereof, will be best understood from the following detailed description of preferred embodiments when read with reference to the accompanying drawings.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 shows a partial cross-section of a power hand tool having a sealing washer constructed in accordance with a first embodiment of the invention;
FIG. 2 shoes a cross-section of the sealing washer in FIG. 1.
FIG. 3 shows a cross-section of a second embodiment of the sealing washer according to the invention; and
FIG. 4 shows a cross-section of a third embodiment of the sealing washer according to the invention
DETAILED DESCRIPTION OF THE DRAWINGS
The power hand tool 1 shown in FIG. 1 shows a gearbox casing 3 mounted on a motor casing 2. The motor casing 2 encloses a motor compartment 4. In this, an electric motor with a rotor 5, not described in further detail here, is fitted. Its shaft 6 drives, for example, via an angular gear not described in further detail here, a second shaft 7 serving as a tool spindle. One end of the shaft 6 projects through a first shaft opening 8 into the gearbox casing 3.
The first shaft opening 8 is closed by a sealing washer 9 which sits on the shaft 6 and turns with it. An unwanted leakage of lubricant from the gearbox casing 3 into the motor compartment 4 is thus prevented.
For the second shaft 7, there is a second shaft opening 10 on the gearbox casing, on the gear side, which leads outside. This is sealed by means of a second, ring-shaped sealing washer 11, so that the penetration of lubricant along the second shaft 7 to the outside is prevented.
The detail from FIG. 1 represented in FIG. 2 shows the sealing washer 9 between the gearbox casing 3 and motor compartment 4 sitting hub-like, in the form of a punched disk, directly on the shaft 6. The circumference of the sealing washer 9 to
REFERENCES:
patent: 1771440 (1930-07-01), Jeffries
patent: 2088330 (1937-07-01), Madsen
patent: 2101305 (1937-12-01), Albertson
Parker Roscoe V.
Robert & Bosch GmbH
Striker Michael J.
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