Expanded – threaded – driven – headed – tool-deformed – or locked-thr – Externally threaded fastener element – e.g. – bolt – screw – etc. – Separate head element
Patent
1993-01-13
1995-01-17
Lindsey, Rodney M.
Expanded, threaded, driven, headed, tool-deformed, or locked-thr
Externally threaded fastener element, e.g., bolt, screw, etc.
Separate head element
411383, 411403, 411408, F16B 2300
Patent
active
053821254
DESCRIPTION:
BRIEF SUMMARY
BACKGROUND OF THE INVENTION
The invention relates to a screw unit with a closing screw having a screw slot for the aseptic closing of an internal thread, particularly for closing an internal thread in a member to be implanted in bone material for receiving an implant post or the like.
Enossal implants, i.e. members to be implanted in the jawbone, are e.g. known from EP 0 216 031 A1 and have proved extremely satisfactory in practice. During the implantation of such members absolute sterility must be ensured in order to keep the inflammation risk low. An implanted member must initially be engaged by the bone growth prior to the introduction of the implant post or the like. During this time the internal thread of the member is closed, because it would otherwise fillup with dead material, which cannot be transported away.
For introducing the member into the bone, it is conventional practice to improve its handling to screw an insertion post in the internal thread and the post is subsequently removed. The internal thread of the member is subsequently closed with a special closing screw. This screw is removed as soon as the bone has firmly grown onto the member and then an implant post, an implant extension, a post for attachments, etc. or a screw for fixing crowns and other structures in dental prosthetics will be screwed into the implanted member.
SUMMARY OF THE INVENTION
The object of the invention is to provide a possibility during implantation of a member of reliably and precisely handling the member which is provided with a closing screw for the internal thread and which is to be implanted in the bone.
According to the invention this problem is solved in that an introduction post is provided in a firm, but detachable seating on the closing screw. Such a post on which it is possible to act by means of a corresponding special tool, such as e.g. forceps, offers the possibility of a safe and precise handling of the member to be implanted. Following the introduction of the member it can be readily detached from the closing screw and removed. The internal thread remains aseptically closed throughout the entire surgical manipulation. The introduction post is then sterilized together with the screw and mains in its seating on the closing screw for the time necessary for handling the member.
A preferred construction of the inventive screw unit comprises the introduction post being in positive contact with the closing screw in the rotation direction and in frictional contact in the axial direction. This has the advantage that an almost randomly high force can be used in the rotation direction, whereas a relatively shall force is sufficient in the axial direction to release the introduction post from the connection to the closing screw.
It is also recommended to use a closing screw which has a screw slot, which terminates inward of the peripheral edge of the screw head and to provide the introduction post with at least one tongue on which is provided at least one outward bulge resting under clamping action in the screw slot on assembling the introduction post and the closing screw. As a result of such a screw slot and a tongue on the introduction post engaging therewith, it is possible in a particularly effective manner to bring about the desired frictional contact between the introduction post and the closing screw. Such a construction is also advantageous, because such a screw slot can also be used for the reliable application of a conventional screwdriver, such as is e.g. used for removing the screw from the implanted member after the bone has grown onto the implanted member. Thus, it is possible to reliably avoid a slipping off of the screwdriver and consequently any risk of the surrounding tissue being injured. Such a construction leads to no additional corners or edges, where possible inflammation could occur. In addition, a smooth, round outside of the screw is ensured, which does not excessively irritate the surrounding tissue. It is finally also impossible for the tissue to grow into the screw slot.
Acco
REFERENCES:
patent: 2058197 (1936-10-01), West
patent: 2248695 (1941-07-01), Bradshaw
patent: 2631624 (1953-03-01), Wright
patent: 3298273 (1967-01-01), McKelvey
patent: 3979918 (1976-09-01), Vidler
patent: 4793808 (1988-12-01), Kirsch
patent: 4824372 (1989-04-01), Jorneus et al.
patent: 4995810 (1981-02-01), Soderberg
Durr Walter
Kirsch Axel
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