Tool driving or impacting – Drive adjustable to completely change kind of drive – Adjustable to impacting device
Reexamination Certificate
2000-06-24
2001-03-20
Smith, Scott A. (Department: 3721)
Tool driving or impacting
Drive adjustable to completely change kind of drive
Adjustable to impacting device
C173S216000
Reexamination Certificate
active
06202759
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the invention
The present invention generally relates to a switching device for a power tool, and especially to a switching device with a simple rotary collar structure for adjusting the output axle of a power tool to be able to switch between a position for rotation and a position for rotation with impact.
2. Description of the Prior Art
A conventional power tool for driving a screwdriver or a drill can drive only by rotation. Sometimes, a body can not be drilled or a screw in the body can not be drawn out due to the sort of material it is made of or being overly fastened. Some manufacturers have developed output axles for power tools to be able to switch between a position for rotation and a position for rotation with impact in order to have the output axle simultaneously rotate and fast impact axially to hammer a drill into a body to be drilled or to screw out a screw having been overly fastened. In a Taiwan patent application No. 87,210,470, a rotary switching device having both rotation and impact functions is provided to make a power tool work in a more convenient and practical way. However, the rotary switching device includes more elements, the whole structure thereof is more complicated. This makes a higher cost of production.
SUMMARY OF THE INVENTION
The present invention makes improvement against the above stated defect of the stated prior art.
The primary object of the present invention is to provide a rotary switching collar device of simple structure. By the rotation of a rotary collar, up to 360°, the switching collar device can adjust the output axle of a power tool to switch between a position for simple rotation and a position for rotation with impact.
Accordingly, the present invention provides a switching device for a power tool. It is provided on an output axle with a fixing seat, a spring, a fixing ring, a switching member, a fixing gear wheel and a movable gear wheel. These members are assembled in a housing. The fixing gear wheel is fixed in the housing, while the movable gear wheel is movable along the output axle. The output axle is combined with a speed reducer provided in the housing. A rotary collar is provided outside the housing. The external periphery of the switching member is provided with a plurality of protruding blocks with different sizes. The protruding blocks can be matched with a plurality of axial slide grooves provided in the rotary collar. The switching member can be rotated along with the rotation of the rotary collar. The fixing ring is also provided between the fixing seat and the switching member and is provided centrally thereof with a through hole for extending therethrough of the output axle. The through hole is provided on the inner edge thereof with a plurality of notches with their sizes corresponding to those of the aforesaid protruding blocks.
By the rotation of the rotary collar, the output axle can be retracted into the housing by an axial force to make contact of the movable gear wheel with the fixing gear wheel, when the protruding blocks on the switching member are aligned with the corresponding notches in the fixing ring. In this way, an axial impact can be generated during the rotation of the output axle. When the axial force is relieved of, the output axle is restored to its original position by the spring. Furthmore, when the protruding blocks on the switching member is not aligned with the corresponding notches in the fixing ring, the output axle cannot be moved axially, and can only do simple rotation.
The present invention will be apparent in its objects and functions after reading the detailed description of the preferred embodiment thereof with reference to the accompanying drawings.
REFERENCES:
patent: 5375665 (1994-12-01), Fanchang et al.
patent: 5451127 (1995-09-01), Chung
patent: 5531278 (1996-07-01), Lin
patent: 5711380 (1998-01-01), Chen
patent: 5842527 (1998-12-01), Arakawa et al.
patent: 6045303 (2000-04-01), Chung
patent: 6142242 (2000-11-01), Okumura et al.
Power Network Industry Co., Ltd.
Smith Scott A.
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