Tools – Wrench – screwdriver – or driver therefor – Handle clutched to head
Reexamination Certificate
2000-01-13
2001-03-27
Meislin, D. S. (Department: 3723)
Tools
Wrench, screwdriver, or driver therefor
Handle clutched to head
C081S177850
Reexamination Certificate
active
06205890
ABSTRACT:
BACKGROUND
The present invention relates to ratchet wrenches such as socket wrenches, and in particular to ratchet wrenches with improved tool release mechanisms that resist inadvertent operation and to ratchet wrenches with improved direction control of the ratchet mechanism.
U.S. Pat. No. 3,208,318 discloses an effective tool release mechanism for tools such as sockets. In the disclosed system a control rod is axially slidable in a drive stud of the wrench, and the control rod defines a ramp surface on which a ball rides. A spring biases the control rod outwardly to a rest position, in which the ball positively engages an accommodating recess in a tool such as a socket. When it is desired to release the socket from the drive stud, the control rod is depressed against the biasing force of the spring, thereby allowing the ball to move down the ramp to a position which allows removal of the socket.
The tool release mechanism of the above-identified patent has been found to be reliable and effective in use. However, the possibility exists that under some circumstances a user may inadvertently depress the control rod while using the wrench. This may happen for example if the head of the wrench is placed in the palm of the user's hand. In this case the palm of the user's hand can come into contact with the upper end of the control rod, and can inadvertently depress the control rod while the wrench is in use, thereby inadvertently releasing the socket. One object of the embodiment described below is to overcome this potential drawback of the prior art.
Roberts U.S. Pat. No. 4,420,995 discloses a tool release mechanism for tools such as sockets. In the disclosed ratchet mechanism a ratchet wheel is provided with an annular raised boss on the side of the ratchet wheel opposite the drive stud, and this boss fits within a recess in the head of the wrench. The boss resists forces tending to decenter the ratchet wheel with respect to its axis of rotation.
Conventional ratchet wrenches are provided with only two stable positions of the ratchet mechanism: forward and reverse. This can represent a limitation in some situations.
SUMMARY
The present invention is defined by the following claims, and nothing in this section should be taken as a limitation on those claims. By way of introduction, the embodiments described below provide a mechanical interlock between the direction control element and the tool release mechanism of a ratchet wrench. The direction control element is coupled to the ratchet mechanism of the wrench to select a ratchet direction for the ratchet mechanism. For example, the direction control element can move from a first position to select a forward (tightening) direction, to a second position to select a non-ratcheting (e.g. free-wheeling or non-rotating) action, to a third position to select a reverse (loosening) direction for the ratchet mechanism. The direction control element is coupled to the tool release mechanism such that inadvertent operation of the tool release mechanism is impeded when the direction control element is in the first or third ranges of positions to select either the forward or the reverse direction. It is only when the direction control element is in the second range of positions to select the non-ratcheting action that the ratchet control mechanism can readily be used to release a socket.
Many alternative mechanical arrangements can be used to perform these functions, as described below. For example, the coupling between the direction control element and the tool release mechanism can be positioned externally or internally of the wrench handle. If desired, the ratchet wheel of the ratchet mechanism may include an annular recess on a face of the ratchet wheel opposite the drive stud. The handle of the wrench can include a protruding centering element that extends into the recess of the ratchet wheel to center the ratchet wheel.
REFERENCES:
patent: 3208318 (1965-09-01), Roberts
patent: 4300413 (1981-11-01), Garofalo
patent: 4420995 (1983-12-01), Roberts
patent: 4699028 (1987-10-01), Bosque
patent: 4848196 (1989-07-01), Roberts
patent: 5178047 (1993-01-01), Arnold et al.
patent: 5386747 (1995-02-01), Grover
patent: 5503048 (1996-04-01), Moon
Davidson John B.
Roberts Peter M.
Brinks Hofer Gilson & Lione
Joda Enterprises, Inc
Meislin D. S.
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