Expanded – threaded – driven – headed – tool-deformed – or locked-thr – Having structure to restrict rotation of threaded – mating... – Comprising a thread lock
Patent
1993-01-15
1996-08-20
Saether, Flemming
Expanded, threaded, driven, headed, tool-deformed, or locked-thr
Having structure to restrict rotation of threaded, mating...
Comprising a thread lock
411418, F16B 3934, A61C 800
Patent
active
055473245
DESCRIPTION:
BRIEF SUMMARY
BACKGROUND OF THE INVENTION
The invention relates to a member provided with an external screw thread.
As a function of the intended use and in the case of screw connections, it is important to a greater or lesser extent to prevent loosening by means of a rotation preventing means. It is therefore inevitable e.g. in dental prosthetics, for screw connections to have a detachable, but firm seating. Loosening must in particular be prevented in the case of parts which are directly screwed into an implant, such as e.g. implant extensions, implant posts, attachment posts, etc., or in the case of screws used for fixing crowns, bridges and other structures in dental prosthetics.
German patent 39 17 690 already discloses for this purpose a spacer sleeve stop, which has a ring nut-like construction and which can be screwed by means of an internal lock thread with a much smaller pitch than the insert thread of a spacer sleeve bottom onto an external thread provided on the bottom close to the distal edge. Thus, the member, the spacer sleeve top and spacer sleeve bottom can be locked and braced together, which prevents rotation of both the spacer sleeve bottom which receives the implant post and the spacer sleeve top.
German patent application P 40 28 855.2 (addition to German patent 39 17 690) describes a corresponding further development of the rotation-prevented individual tooth implant according to the main patent, in which rotation is reliably prevented by simpler means using positive engagement chambers or members.
Both from the aforementioned prior art regarding single tooth implants and other members provided with external screw threads in the field of dental prosthetics and the like, no rotation prevention means is known which can do without some type of positive engagement. As a result the construction of such rotation prevention means in the given dimensions of the implant or prosthetics is often complicated or relatively expensive.
SUMMARY OF THE INVENTION
The object of the invention is to provide a member preventing in a particularly simple and inexpensive manner an extraction or loosening of the screw connection.
According to the invention this object is obtained in that at least an end portion of the screw thread is provided with at least one plastic part which has skirt means for at least partly covering the thread and/or at least partly replacing the thread.
Due to the fact that in portions of the screw thread there is a direct contact between the inventive plastic part and the corresponding internal screw thread, there is a squeezing of the plastic material in these portions during screwing in the screw. As a result of the frictional contact brought about in this way, a reliable rotation prevention is ensured in a surprisingly simple and effective manner.
The invention optionally provides for an attachment on the tip of the screw thread and in the extension thereof and which engages with a corresponding recess or socket in the plastic part. This ensures that the inventive plastic part can be placed in a simple and reliable manner on the screw thread tip.
It is particularly preferred if both the attachment and the recess in the plastic part are cylindrical and are positioned centrally with respect to the cross-section of the screw thread or the plastic part.
The invention further proposes that the plastic part is constructed so as to taper conically towards its tip. It is particularly preferred for the screw thread to project into the plastic part at least in a partial area. As a result the inventive member can easily be screwed in, because its threads can pass in largely unimpeded manner into the threads of the complimentary internal screw thread. A frictional contact only occurs when the tip of the plastic part strikes a corresponding inner end of the internal screw thread and the sides of the plastic part are consequently pressed outwards.
Alternatively thereto (but optionally also in addition thereto) according to a further embodiment of the invention, at least the end portion of the screw threa
REFERENCES:
patent: 2568640 (1951-09-01), Kindelberger
patent: 2730154 (1956-01-01), Aspey
patent: 2852056 (1958-09-01), Rapata
patent: 3182702 (1965-05-01), Nason et al.
patent: 3195599 (1965-07-01), Brook
patent: 3319689 (1967-05-01), McDougall et al.
patent: 3439575 (1969-04-01), Gifford
patent: 4334865 (1982-06-01), Borle
patent: 5026285 (1991-06-01), Durr et al.
patent: 5125840 (1992-06-01), Durr et al.
Durr Walter
Kirsch Axel
Eberle Medizintechnische Elemente GmbH
IMZ Fertigungs-und Vertriebsgesellschaft fur dentale Technologie
Saether Flemming
LandOfFree
Member provided with an external screw thread does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Member provided with an external screw thread, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Member provided with an external screw thread will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-2326193