Tools – Wrench – screwdriver – or driver therefor – Machine
Reexamination Certificate
1999-06-25
2001-10-09
Meislin, D. S. (Department: 3723)
Tools
Wrench, screwdriver, or driver therefor
Machine
Reexamination Certificate
active
06298752
ABSTRACT:
BACKGROUND OF THE INVENTION
The present invention relates to continuous-turning fluid operated wrenches.
Continuous turning fluid-operated wrenches are known in the art for example as disclosed in our U.S. Pat. Nos. 4,409,865 and 4,644,829. While the continuous turning fluid operated wrenches have been satisfactory, several new and important improvements had to be made under consideration of the fact that these tools are used for torque in excess of 500 ft.lbs. with the largest one going over 80,000 ft.lbs.
During the operation of continuous-turning fluid operated wrenches, on many occassions the bolt torsion and the flex of the tool parts lock the engaged pawl against the ratchet tooth in the pawl/ratchet mechanism. This creates enormous difficulties in removing the tool from a fastener which is tightened by the tool. In this situation it is not possible simply to reverse the drive and to release the corresponding pawl.
SUMMARY OF THE INVENTION
Accordingly, it is an object of present invention to provide a continuous-turning fluid operated wrench which avoids the disadvantages of the prior art.
More particularly it is an object of present invention to provide a continuous turning fluid operated wrench that can be taken off the nut when the bolt torsion and the flex of the tool parts lock the engaged pawl against the ratchet tooth in their rewinding process, with the use of a disengagement device that lets the tool operator disengage one of the driving pawls so as to allow the ratchet to turn slightly backwards and release the torsion build up and the flex in the tool parts to free the tool from the job.
SUMMARY OF THE INVENTION
Accordingly, it is an object of the present invention to provide a continuous turning fluid-operated wrench which avoids the disadvantages of the prior art.
In keeping with these objects, our features of the invention resides in a tool which has fluid-operated drive means including a cylinder, and a piston reciprocatingly movable in said cylinder and having a piston rod with a piston rod end; a ratchet mechanism having a ratchet provided with a plurality of teeth, and at least two pawls operatably connectable with said piston rod end and engageable with teeth of said ratchet so that during an advance stroke of the piston one of the pawls engages with at least one ratchet tooth while the other of pawl ratchets over at least one ratchet tooth, while during a return stroke of the piston the other of the pawls engages with at least one ratchet tooth while the one pawls ratchets over at least one ratchet tooth; and disengaging means which is separate from said drive means and actuatable by an operator so as to act on at least one of said at least two pawls to disengage said at least one pawl from and to lift said at least one pawl above said teeth of said ratchet, so as to permit said ratchet to turn backwards to release a buildup torsion and material flex, so that the fluid operated wrench can be taken off a job.
When the fluid operated wrench is designed in accordance with the present invention, then it is possible in the event when the bolt torsion and the flex of the tool parts lock the engaged pawl against the ratchet tooth, to easily disengage the pawl from the teeth of the of the ratchet and to lift it above the teeth of the ratchet, so as to permit the ratchet to turn backwards and to remove the fluid operated wrench from a fastener.
The novel features which are considered as characteristic for the present invention are set forth in particular in the appended claims. The invention itself, however, both as to its construction and its method of operation, together with additional objects and advantages thereif, will be best understood from the following description of specific embodiments when read in connection with the accompanying drawings.
REFERENCES:
patent: 2712256 (1955-07-01), Fish
patent: 4409865 (1983-10-01), Krautter et al.
patent: 4448096 (1984-05-01), Collins
patent: 4644829 (1987-02-01), Junkers
patent: 4671142 (1987-06-01), Junkers
patent: 5029497 (1991-07-01), Junkers
patent: 5318397 (1994-06-01), Junkers
patent: 5979273 (1999-11-01), Walton
patent: 6112622 (2000-09-01), Reiman
patent: 40 42 070 (1991-07-01), None
patent: 0 754 527 (1997-01-01), None
Meislin D. S.
Striker Michael J.
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