Tools – Wrench – screwdriver – or driver therefor – Handle clutched to head
Patent
1986-01-21
1988-01-12
Olszewski, Robert P.
Tools
Wrench, screwdriver, or driver therefor
Handle clutched to head
81117, 811763, B25B 1346
Patent
active
047183152
DESCRIPTION:
BRIEF SUMMARY
BACKGROUND OF THE INVENTION
The invention relates to an automatically opening and closing combined open-ended spanner and rapid screwing tool having a ratchet action, which is equipped with an integrated locking element and adjusting system. The ratchet-like wrench, or automatic wrench has an auxiliary assembling device and interchangeable, spanner-width inserts for each particular wrench size. As a result, it is extremely versatile and particularly easy and convenient to handle upon tightening and freeing fastening elements, preferably hexagonal-head bolts and hexagonal nuts, without withdrawal, repositioning or removal of the wrench during a gripping or screwing action and once it has been fitted.
DE-PS 449510 discloses a wrench of the kind described above, in which the return spring located in the fixed jaw acts directly on the aperture-side lever arm of the wrench handle, so that the same actuates the movable jaw in such manner that it operates similarly to pincers on the bolt or nut element which is to be freed or tightened. This pincer-like action of the movable jaw has the disadvantage that the fastening element, in the form of the nut or bolt head, which is to be freed or tightened is exposed to a comparatively high degree of wear during the ratchet-like take-up displacement of the tool, so that the edges of the fastening elements may be damaged, after repeated application of the wrench, to such a degree that the application of a standard ring spanner is no longer possible. On the other hand, the operating surfaces of the wrench also undergo a comparatively high degree of stress, thereby adversely affecting their durability. Another disadvantage of this known wrench is to be seen in that the return spring acts on the pivotable jaw with a very large leverage in the ratchet position of the wrench, so that the ratchet action may, as a rule, be brought to bear effectively only if the handle is made to follow on positively and at comparatively high speed. Furthermore, this known ratchet-like wrench is constructed with a comparatively massive spanner head and is thus comparatively unwieldy so that it has not hitherto gained acceptance in this form of construction.
SUMMARY OF THE INVENTION
The invention has the fundamental problem of devising a ratchet-like wrench which, with lesser strain on the mutually engaged surfaces of the coupling means and the wrench jaws, may be actuated in a very uncomplicated manner and operates particularly smoothly but which nevertheless operates in force-locked manner, is very stable and may consequently reliably transmit large forces.
Any pincer action by the two wrench jaws is prevented by the features according to the invention. On the contrary, the two jaws have an operating position which is predetermined in a geometrically precise manner and in which the movable jaw is supported on the stationary jaw in a manner defined by the coupling member and the rocker, so that the hexagonal bolt head or nut which is to be freed or tightened is embraced in a wholly slip-proof manner at this instant. On the other hand, the movable jaw assumes a second unlocked state in the ratchet position of the wrench, which is again precisely defined as regards positioning and, in which the contact force between the movable jaw or aperture and the fastening means is practically nil, so that the surfaces in mutual engagement are treated in the least harmful manner. The measures according to the invention provide the particularly advantageous possibility of optimising the engagement between the pivotable jaw, the coupling element and the rocker, in such manner that a sufficiently large pivotal action is produced for the movable jaw by a very small angle of pivotal displacement of the wrench handle, thereby to cause the tool to follow on in ratchet-like manner with the application of very little force. In this way the lever deflection of the handle may successfully be kept below 15.degree. upon appropriate optimisation of the form of the rocker, coupling element and handle-side lever arm of the
REFERENCES:
patent: 1183371 (1916-05-01), Ginsburg
patent: 2618996 (1952-11-01), Logan
patent: 2643568 (1953-06-01), Milentz
Olszewski Robert P.
Vaught Bradley I.
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