Electrical generator or motor structure – Dynamoelectric – Rotary
Reexamination Certificate
2000-10-25
2002-11-12
Tamai, Karl (Department: 2834)
Electrical generator or motor structure
Dynamoelectric
Rotary
C310S239000, C310S050000
Reexamination Certificate
active
06479918
ABSTRACT:
FIELD OF INVENTION
The invention relates to a novel economic easy and quick assembly of a hand-held drilling or screwing implement, with a housing, a handle protruding perpendicularly from the housing, an electrical driving motor, a carbon brush holder ring disposed co-axially to the driving motor and a switching body, interacting with the carbon brush holder ring.
BACKGROUND INFORMATION AND PRIOR ART
U.S. Pat. No. 3,440,465 discloses a hand-held electrical tool, for which the direction of rotation of the driving motor can be reversed. This electrical tool has a housing and a handle protruding perpendicularly from the housing. An actuating element of a switching body, disposed in the housing, is freely accessible, over an opening in the housing opposite to the handle. The actuating element can be shifted to a limited extent in the circumferential direction of the driving motor, for example, from a clockwise running position into a counter-clockwise running position. This switching body is connected in a rotationally locking manner with a carbon brush holding ring, which is disposed coaxially with the driving motor and at which there are two carbon brush holders, which are diametrically opposite one another and have, in each case, one carbon brush. These carbon brush holders are disposed along an axis extending essentially parallel to the longitudinal extent of the handle.
The carbon brush holding ring is disposed between two components, which are bolted together and can be rotated to a limited extent in the circumferential direction. In the region of the carbon brush holder ring, a portion of the housing is formed by a removable cap, which covers the switching body and the carbon brush holder ring. In the interior of the cap, there is a further part of the housing, which is provided with an accommodating borehole. One of the two components, between which the carbon brush holder ring is disposed, is connected firmly with the further part of the housing with the help of a bolted connection. A portion of the accommodating borehole, facing the commutator of the driving motor, serves to accommodate a bearing, which is disposed in the free end region of the motor shaft of the driving motor on the commutator side. The part of the accommodating borehole, averted from the commutator, has a smaller diameter and serves to accommodate and form a bearing for the switching body.
The assembly of this known, hand-held electrical tool is composed of a large number of steps. To begin with, the stator is incorporated in the housing. Subsequently, the carbon brush holder ring and the components interacting therewith are fastened to the further part of the housing. Subsequently, the rotor of the driving motor is pushed through an opening of the housing on the side, seating the tool, into the stator and the switching body is slipped onto the further part of the housing. Finally, the opening of the housing on the side, on which the tool is seated, is closed and the cap is placed on the remaining part of the housing. Because of the large number of steps, which require much time, an economic production is not possible.
OBJECT OF THE INVENTION
It is an object of the invention to provide an economic drilling or screwing implement, which can be constructed easily and assembled quickly.
SUMMARY OF THE INVENTION
This objective is accomplished by a drilling and/or screwing implement, with a housing, a handle protruding essentially perpendicularly from the housing, an electrical driving motor, a carbon brush holder ring disposed coaxially to the driving motor and rotatable in a circumferential direction, and a switching body, interacting rotationally locked with the carbon brush holder ring, the carbon brush holder ring having two carbon brush holders disposed along an axis extending essentially parallel to the longitudinal extent of the handle and lying opposite one another, and the switching body having an actuating element on one side opposite to the handle, wherein the carbon brush holder ring is connectable axially positively with the stator.
Because of the inventive axial, positive fixing of the carbon brush holder ring at the stator, it is possible to assemble these two parts as a sub-assembly, before they are inserted in the housing; the sub-assembly can then be inserted quickly and easily in only one step in the housing.
So that the carbon brush holder ring can be fixed to the stator, the carbon brush holder ring has at least two stop surfaces, which point away from the stator and interact with at least two counter-surfaces of the stator. The stop surfaces, as well as the counter-surfaces extend in a direction essentially perpendicularly to the longitudinal axis of the driving motor.
A limited ability to rotate the carbon brush holder ring relative to the stator is achieved by advantageously having each stop surface at a projection of the carbon brush holder ring protruding in the direction of the stator. Each of the two projections protrudes, for example, in a guiding region of the stator, which is in an end region of the stator facing the carbon brush holder ring. Each guiding region extends over a portion of the periphery of the stator and is limited in both directions by a stop, at which the projections come into contact, depending on the position of the carbon brush holder.
So that the carbon brush holder ring can be mounted quickly at the stator, without having to resort to any additional installation tools, the projection preferably is constructed so that it can be bent in the radial direction.
Advantageously, a section, between the stop surface and the free end of the projection, tapers towards the free end of the projection. By these means, when the stator and the carbon brush holder ring are connected axially, an automatic bending apart of the two projections is achieved as soon as the tapering section of the projections comes into contact with a corresponding outer contour of the stator. When the end position of the carbon brush holder ring is reached, the stop surfaces of the projections can latch behind the counter-surfaces of the stator in that the outwardly bent projections can swing back once again into their normal position.
In order to be able to achieve as slender a construction of the drilling and screwing implement as possible in a direction, perpendicularly to the longitudinal extent of the handle and perpendicularly to the longitudinal extent of the driving motor, each projection advisably is disposed in the region of a carbon brush holder.
So that, on the one hand, the two connecting regions between the stator and the carbon brush holder can be reached easily and, on the other, the carbon brush holder ring can be rotated to a limited extent in the circumferential direction with respect to the stator, the counter-surface preferably is disposed in the circumferential region of the stator and extends over a portion of the periphery of the stator.
In order to be able to exclude a possible clearance between the stop surfaces of the carbon brush holder ring and of the counter-surfaces of the state, at least two springs, which force the stop surfaces against the counter-surfaces, are advantageously disposed between the carbon brush holder ring and the stator. The springs are, for example, compression springs, which ensure that the stator and the carbon brush holder ring are pressed apart, so that the stop surfaces and the counter-surfaces lie in contact with one another and the carbon brush holder ring is held in the appropriate position for clockwise or counter-clockwise rotation.
With the help of the axial, positive connection, the carbon brush holder ring is fixed only axially with respect to the stator. The radial support and the rotatable mounting of the carbon brush holder ring are accomplished preferably by a bearing at the inner wall of the housing, interacting with the outer contour of the carbon brush holder ring.
The preferred embodiments of the invention are described herein with reference to the accompanying drawings, in which:
The various features of novelty which cha
Brami Georg
Burger Helmut
Lübkert Ernst-Rudolf
Troeder Lutz
Hilti Aktiengesellschaft
Sidley Austin Brown & Wood LLP
Tamai Karl
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