Expanded – threaded – driven – headed – tool-deformed – or locked-thr – Threaded fastener locked to a discreet structure – Fastener – or coaxial adjunct therefor – having sidewardly...
Reexamination Certificate
2001-03-28
2002-07-30
Saether, Flemming (Department: 3627)
Expanded, threaded, driven, headed, tool-deformed, or locked-thr
Threaded fastener locked to a discreet structure
Fastener, or coaxial adjunct therefor, having sidewardly...
C411S149000
Reexamination Certificate
active
06425719
ABSTRACT:
BACKGROUND OF THE INVENTION
The invention relates to a screw-locking device. Such screw-locking devices have been disclosed in a wide variety of embodiments. In general, the toothed disks are made of spring plate or plastic and are designed to be elastic in such a way that locking is effected in a certain tightening position determined by the screw thread of the joint bolt, and reduction in the tightening due to slackening of the screw is prevented. Such screw-locking devices can be used wherever the slackening of a screw or a nut is to be prevented, even if the components connected thereto are subjected to vibration. Examples of this are described in DE-A 16 25 279, DE-A 24 13 760 and U.S. Pat. No. 5,314,279.
SUMMARY OF THE INVENTION
A specific application of the screw-locking device according to the invention is the use in connection with garden shears, in particular pruning shears. In this case, it is necessary to occasionally separate the two legs of the shears from one another by unscrewing the joint bolt in order to carry out a blade change, for example, or to clean the shears. Due to repeated dismantling and assembly, the conventional screw-locking devices are often stressed and deformed in such a way that their locking effect diminishes and the joint bolt is often tightened to a greater extent than appropriate for the functioning of the legs of shears, which are mutually pivotable.
The object of the invention is therefore to design a screw-locking device of the generic type, suitable in particular for garden shears, in such a way that the operability of the anti-rotation locking is reliably retained even after repeated dismantling and assembly operations.
This is attained by a screw-locking device which has catch teeth on a spring collar arranged not in the form of a continuous toothed rim, as is the case in known screw-locking devices, but in a spaced apart manner to interact as individual teeth with a toothed rim of a catch disk. Accordingly, webs, which are secured to an inner ring and an outer ring and form the catch teeth of the spring collar, can yield about a radially running axis and, after crossing a respective tooth of the catch disk, return into the catch position. This results in better elasticity while the locking force remains constant.
The circumferential distance between two radial tooth webs of the spring collar is expediently matched to the tooth spacing of the catch disk in such a way that a material-free intermediate space of one tooth or several teeth remains between two teeth, engaging on the web teeth, of the toothed rim,of the catch disk. The result of this is that, during the relative rotation between the catch disk and spring collar, the catch webs exert a radial tensile force outward on the inner ring, so that the latter is elastically deformed in a polygonal manner and returns to the original shape after the teeth have engaged in the catch position, as a result of which the elastic yielding displacement is increased.
The resistance of the spring arms to deflection is selected to be so great that the torque which occurs when cutting a branch or the like, and which could result in slackening of the joint screw, is resisted to such a high degree that the screw cannot slacken. The continuously effective seating of the screw-locking device is brought about owing to the fact that the deflections of the radial spring webs or of the inner ring, which occur during the interlocking, always take place within the elastic range.
One of the two parts, namely the catch disk or spring collar, can be connected in a rotationally locked manner to the leg of the shears which has the tapped hole for the joint bolt, while the other part can be connected in a rotationally locked manner to the joint bolt. The screw-locking device consisting of spring collar and catch disk can be made of any desired elastic material. However, it is preferably made of an elastic plastic selected in accordance with the requirements.
Refinements of the invention follow from the subclaims:
REFERENCES:
patent: 969397 (1910-09-01), Patridge
patent: 1654789 (1928-01-01), Clegg
patent: 3263727 (1966-08-01), Herpolsheimer
patent: 5314279 (1994-05-01), Ewing
patent: 5533849 (1996-07-01), Burdick
patent: 5606753 (1997-03-01), Hashumoto
patent: 5967721 (1999-10-01), Giachinta
patent: 1625279 (1970-01-01), None
patent: 2413760 (1974-11-01), None
patent: 0131556 (1985-01-01), None
patent: 94/03736 (1994-02-01), None
Ostrolenk Faber Gerb & Soffen, LLP
Saether Flemming
WOLF-Garten GmbH & Co. KG
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