Expanded – threaded – driven – headed – tool-deformed – or locked-thr – Externally threaded fastener element – e.g. – bolt – screw – etc. – Head having counter-sinking means
Patent
1999-05-10
2000-07-11
Wilson, Neill
Expanded, threaded, driven, headed, tool-deformed, or locked-thr
Externally threaded fastener element, e.g., bolt, screw, etc.
Head having counter-sinking means
411412, 411418, 411426, F16B 502, F16B 2500, F16B 3504
Patent
active
06086303&
DESCRIPTION:
BRIEF SUMMARY
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a spacer screw having a first thread section which can be screwed into a base element, a head section with a free screw head-shaped end section an anchoring section having coaxially arranged ring-like projections, a shank section between the head section and the first thread section, and a recess for the insertion of a tool at the end face.
2. Description of the Prior Art
A spacer screw of this kind is known from U.S. Pat. No. 4,808,051. The screw is a countersunk screw with constant core diameter. The screw has a thread section at the front end, an anchoring section and a shank section arranged between them. The anchoring section comprises a plurality of ring-like projections which broaden in the direction towards the screw head. This screw is used to secure a construction element to a base element.
It has proved to be a disadvantage that this screw only has a restricted field of use. On screwing the thread section into the base element the force which has to be applied must be so large that the anchoring section is driven into the construction element. From that it follows that the construction element must always have a lower strength than the base element.
In another known embodiment the spacer screw has a first thread section at the front end, a second thicker thread section at the rear end and a shank section connecting the thread sections.
This screw has the disadvantages that the desired spacing between the base element and the construction element must previously be determined by spacers, because the correction of the spacing means that the screw is turned out of the construction element on being unscrewed because of the same thread pitch of the thread sections, and that the construction element can be pulled off from the thicker thread section as a result of the lack of a screw head, in particular with soft types of wood.
The invention is based on the object of providing a spacer screw which is not subjected to the above-named restrictions.
SUMMARY OF THE INVENTION
The objects of the present invention are achieved by forming a second thread section between the anchoring section and the shank section, with the anchoring section and the second thread section having a larger core diameter than the first thread section.
The advantages which can be achieved by the invention are to be seen in the simplicity of use and in the advantageous price.
BRIEF DESCRIPTION OF THE DRAWINGS
In the following the invention will be explained with reference to the accompanying drawings.
The drawings show:
FIG. 1 a view of an embodiment of a screw in accordance with the invention,
FIG. 2 a section along the line II--II in FIG. 1, and
FIG. 3 a view of a part of another embodiment of the screw of the invention .
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT
Reference is made to the FIGS. 1 and 2. The spacer screw contains a first thread section 1 at the front end, a shank section 2 which adjoins the first thread section, a head section 3 at the rear end, a second thread section 4 which is formed between the head section and the shank section and a recess for the insertion of a tool. The thread of the first and second thread sections 1 and 4 has the same pitch.
The head section 3 has a head-like section which is formed as a ring-like projection 5 and an anchoring section 6 with five ring-like projections 7, with the projections 5, 7 being coaxial and spaced apart from one another. The projection 5 is made flush with the end of the screw and has an outer diameter which is larger than the outer diameter of the following five projections 7 in order to achieve a clean termination of the position where it is screwed in. Each projection has a conical cross-section which broadens towards the rear end of the screw starting from the core diameter. This design has the advantage that an action resembling that of a screw head is achieved thereby, which prevents the construction element being pulled off from the screw. The anchoring sect
REFERENCES:
patent: 4808051 (1989-02-01), Gietl
patent: 4959938 (1990-10-01), De Caro
patent: 5259398 (1993-11-01), Vrespa
patent: 5531554 (1996-07-01), Jeanson et al.
patent: 5909992 (1999-06-01), Wu
International Search Report, No. PCT/CH96/00025 dated Oct. 1, 1996.
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