CA2534016A1

CA2534016A1 - Wood screw

Info

Publication number: CA2534016A1
Application number: CA 2534016
Authority: CA
Inventors: Achmed N. Sadik; Martin J. Marcus
Original assignee: Individual
Current assignee: Individual
Priority date: 2005-12-19
Filing date: 2005-12-19
Publication date: 2007-06-19

Abstract

The present invention provides a wood screw comprising an elongated threaded shank, which is provided with e.g., special spiral threads thereon, a narrow, wood-penetrating base at one end of the threaded shank, and a torque-receiving head at the other end of the threaded shank. The threads of the screw include at least one spur, which is formed either between two of the threads near the narrow, wood-penetrating lower end of the wood screw, or on one of the threads near the narrow, wood-penetrating lower end of the wood screw, or at the base of the wood screw. Such spur projects from the shank and is substantially-parallel to, or on, the spiral threads, to provide a projecting point. This projecting point is so configured and arranged that it acts as a type of barb, and does not create a significant impediment against the securing of the wood screw by applying a torque to the screw in the direction of the hand of the screw (i.e., a right hand), but creates an impediment towards a torque in an opposite hand direction (i.e., a left hand), which would tend to loosen the screw.

Description

WOOD SCREW

[0001] This invention relates generally to wood screws. It relates, more particularly, to wood screws in which the tendency for the screws to become loose with time, vibration or other causes is greatly minimized.

BACKGROUD ART

[0002] Various types of screws have been provided which include a loosening prevention function. Some of the patents rely for their loosening prevention function on a particular arrangement and structure of the actual threads of the screw. Among such patented screws are the following:

[0003] US Patent No. 4,252,168 patented Feb 24, 1981, by The Lamson &
Sessions Co. for THREAD CONVOLUTION.

[0004] US Patent No. 5,188,496 patented Feb 23, 1993, by L. N. Giannuzzi for SELF-TAPPING SCREW-TYPE MASONRY ANCHOR.

[0005] US Patent No. 5,672,037, patented Sep 30, 1997, by Iwata Bolt KK for LOOSENING AND DISLODGING PREVENTING SCREW.

[0006] US Patent No. 6,152,666 patented Nov 28, 2000, by U. Walther et al for SCREW FOR USE AS A FASTENER IN FIBROUS MATERIAL SUCH AS WOOD.

[0007] US Patent No. 6,216,510, patented April 17, 2001, by The Holistic Environment Creators Co. Ltd for METHOD OF PRODUCING SELF-LOCK SCREW.

[0008] US Patent No. 6,328,516, patented, Dec. 11, 2001, by U. Hettich for SCREW WITH CUTTING EDGE.

[0009] US Patent No. 6,514,025, patented Feb 4, 2003, by Y. Ishimori for SCREW MEMBER WITH ELASTICALLY DEFORMABLE FEATURES.

I

[00010] US Patent No. 6,860,690, patented Mar. 1, 2005, by T.Watanabe for SCREW MEMBER WITH BITING FEATURES.

[00011] Other of the patents rely on cooperation between the article being fastened and the base of the screw which bites into the article being fastened. Among such patented screws are the following:

[00012] US Patent No 3,286,579 patented Nov. 22, 1966, by L. J. Lovisek for SELF-TAPPING SCREW.

[00013] US Patent No 4,820,235, patented Apr 11, 1989, by D Weber et al for THREADED FASTENER.

[00014] US Patent No 5,199,839, patented Apr 6, 1993, by L.DeHaitre for FASTENER SCREW HAVING IMPROVED INSTALLATION AND SELF-LOCKING
CHARACTERISTICS.

[00015] US Patent No 5,570,983, patented Nov. 5, 1966, by A. H. Hollander for REDUCE-FRICTION SCREW.

[00016] Still other patents rely on some means to expand the shank once the screw is in place. Among such patented screws are the following:

[00017] US Patent No 4,411,570, patented Oct 25, 1983, by I. Juric for TAMPER-PROOF FASTENER.

[00018] US Patent No 6,447,227 patented Sept 11, 2002, by D. Crutchley for THREADED FASTENER.

[00019] Yet other patents rely on a projecting screw thread, which is either perpendicular to the longitudinal axis of the screw or at an angle to the base of the head of the screw. Among such patented screws are the following:

[00020] US Patent No 4,144,795, patented Mar 20, 1979, by C. E. Gutshall for LONG-PITCH RE-ROLLED CREST THREAD.

[00021] US Patent No 4,334,814, patented Jun. 15, 1982, for SELF-TAPPING
SCREW FOR USE IN PLASTICS.

[00022] US Patent No 4,653,486, patented Mar 31, 1967, by T. P. Coker, for FASTENER, PARTICULARLY SUITED FOR ORTHOPEDIC USE.
DESCRIPTION OF THE INVENTION

[00023] None of the screws disclosed hereinabove adequately addresses the problem of the loosening of a wood screw upon the passage of time. Such wood screws are widely used for installation in a wood substrate, and frequently are used to affix a wooden, metal or plastic plate or other object to a wooden object. Such screw attachment means can become loose with time, vibration or other causes, tending to unscrew from the wood. Accordingly a need exists to provide a wood screw which resists loosening with time, vibration or other causes.

[00024] An object of a first aspect of the present invention is to provide such a wood screw which addresses the above problem in an elegant simple manner.

[00025] An object of a second aspect of the present invention is to provide such a wood screw which addresses the above problem in an elegant simple manner and which does not significantly increase the cost of manufacturing such screw.

[00026] The present invention provides a wood screw comprising an elongated shank provided with e.g., special spiral threads, a narrow, wood-penetrating end of the elongated shank, and a torque-receiving head at the other end of the shank.
The threads of the screw include at least one spur formed either between two of the threads near the narrow, wood-penetrating end of the wood screw, or on one of the threads near the narrow, wood-penetrating end of the wood screw. Such spur is thus parallel to, or on the threads and projects from the shank to provide a projecting point. This projecting point is so configured and arranged that it does not create a significant impediment against the entry and securing of the wood screw by applying a torque to the screw in the direction of the hand of the wood screw (i.e., a right hand), but the above-mentioned spur acts a type of barb, creating an impediment towards a torque in an opposite hand direction (i.e., a left hand) which would tend to loosen the wood screw.

[00027] By a first variant thereof, the spur projects beyond the diameter of the threads.

[00028] By a second variant thereof, the spur is formed near the narrow, wood-penetrating lower end of the wood screw between two adjacent threads.

[00029] By a third variant thereof, the spur is formed only near the narrow, wood-penetrating lower end of the wood screw between two adjacent threads.

[00030] By a fourth variant thereof, the spur is formed near the narrow, wood-penetrating lower end of the wood screw on one of the threads.

[00031] By a fifth variant thereof, the spur is formed only near the narrow, wood-penetrating lower end of the wood screw on one of the threads.

[00032] By a sixth variant thereof, the spur is formed only at the lower extremity of the wood screw on the last thread.

[00033] By a seventh variant of any of the above six variants, more than one spur is provided on the wood screw.

DESCRIPTION OF THE FIGURES OF THE DRAWINGS

[00034] In the accompanying drawings:

[00035] FIG 1 is central longitudinal section of a wood screw according to an embodiment of the present invention showing a single spur on one right handed thread near the narrow, wood-penetrating base of the threaded end of the wood screw;

[00036] FIG 2 is central longitudinal section of a wood screw according to an embodiment of the present invention showing a single spur between two adjacent right handed threads near the narrow, wood-penetrating base of the threaded end of the wood screw.

[00037] FIG 3 is a plan view of the spur; and [00038] FIG 4 is a cross-section through line Al-Al of Fig. 2.
DESCRIPTION OF AT LEAST ONE MODE FOR CARRYING OUT THE
INVENTION

[00039] As seen in FIG 1, the wood screw 100 has a torque-receiving head 112 of suitable construction and an elongated shank 114 having, e.g. right-handed threads 116 extending from the head 112 to the narrow, wood-penetrating base 118. The wood screw 100 is intended primarily for use in securing two or more pieces of wood together.

[00040] One of the ri ght-handed threads 116-1 near the narrow, wood-penetrating base 118 of the threaded end of the wood screw 100 is a single spur 120. As seen more clearly in Fig. 3 and 4, the spur 120 is integral with thread 116-1 at integral end 122, and terminates in a pointed end 124.

[00041] As seen in FIG 2, the wood screw 200 has a torque-receiving head 212 of suitable construction and an elongated shank 214 having, e.g. right-handed threads 216 extending from the head 212 to the near the narrow, wood-penetrating base 218 of the threaded end of the wood screw. The wood screw 200 is intended primarily for use in securing two or more pieces of wood together.

[00042] Between two adjacent right-handed threads 216-1 and 216-2 near the narrow, wood-penetrating base 218 of the threaded end of the wood screw 200, is a single spur 220. The structure of the spur 220 is identical to the structure of spur 120, but it, of course, is integral with the shank 214 instead of with the thread 216.

[00043] While not shown in Fig. l and Fig. 2, there may be more than one spur 120 or 220 on the wood screw 100 or 200 respectively. Also, although not shown, the spur 120, 220 may be provided at near the narrow, wood-penetrating base 118, 218 of the wood screw 100, 200, rather than between two adjacent threads. Yet still further, the spur 120, 220 may be a notch on a selected thread 116, 216, even though it is not shown in the drawings.

[00044] In use, because the spur 120, 220 has the above-described structure, it does not create a significant impediment against the securing of the wood screw 100, 200 by applying a torque to the wood screw 100, 200 in a first direction, but creates an impediment towards a torque in the opposite direction which would tend to loosen the wood screw 100, 200.

[00045] As used herein, the term "spur" is intended to mean any structure on the wood screw which acts a barb, and does not create an impediment against the securing of the wood screw by applying a torque to the screw in a first direction, but creates an impediment towards a torque in the opposite direction which would tend to loosen the screw.

Claims

1. A wood screw exhibiting enhanced security against removal, from a wood or like substrate, comprising:
an elongated shank provided with special spiral threads;
a narrow, wood-penetrating at one end of said elongated shank, and a torque-receiving head at the other end of said shank;
said threads including at least one spur formed either on a land between two of the threads near the narrow, wood-penetrating end of the wood screw, or on one of the threads near the narrow, wood-penetrating end of said wood screw;
said spur thus being substantially-parallel to, or on, said thread, to provide a penetrating point, said penetrating point being so configured and arranged that it does not create a significant impediment against the entry and securing of the wood screw into a wood substrate by applying a torque to the screw in the direction of the hand of the screw, but said penetrating point acts as a type of barb, to create an impediment to resist a torque applied in an opposite hand direction which would tend to loosen said wood screw.

2. The wood screw as claimed in claim 1, wherein said spur projects beyond the diameter of said threads.

3. A wood screw as claimed in claim 1, wherein said spur is formed in an edge of a thread, and does not project beyond said edge.

4. The wood screw as claimed in claim 1, wherein said spur is formed near the narrow, wood-penetrating end of said wood screw between two adjacent threads.

5. The wood screw as claimed in claim 1, wherein said spur is formed only near the narrow wood-penetrating end of the wood screw between two adjacent threads.

6. The wood screw as claimed in claim 1, wherein said spur is formed near the narrow, wood-penetrating end of said wood screw on one of said threads.

7 7. The wood screw as claimed in claim 1, wherein said spur is formed only near the narrow, wood-penetrating end of said wood screw on the last said thread.

8. The wood screw as claimed in any one of claims 1 to 7, including more than one spur on said wood screw.