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Publication numberUSRE34969 E
Publication typeGrant
Application numberUS 08/113,555
Publication dateJun 13, 1995
Filing dateAug 27, 1993
Priority dateOct 3, 1990
Also published asCA2052667A1, CA2052667C, DE69105444D1, DE69105444T2, EP0479586A1, EP0479586B1, US5061136
Publication number08113555, 113555, US RE34969 E, US RE34969E, US-E-RE34969, USRE34969 E, USRE34969E
InventorsTony L. Dixon, David E. Starke, Frank Piacenti, Robert W. Brown, Jr.
Original AssigneeEmhart Inc.
Export CitationBiBTeX, EndNote, RefMan
External Links: USPTO, USPTO Assignment, Espacenet
Masonry screw anchor
US RE34969 E
Abstract
A masonry screw anchor having two different constant diameter shank portions connected via a taper. Each portion has a set of constant diameter threads and intermediate smaller diameter protrusions with the threads and protrusions on the larger diameter shank portion being larger in diameter than the diameter of the threads and protrusions on the smaller diameter portion.
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Claims(5)
We claim:
1. A masonry screw anchor comprising
an elongated shank portion including a smaller constant diameter portion having a pointed end and an adjacent larger diameter portion joined therewith via a tapered portion
a first set of constant diameter threads on said smaller diameter shank portion,
a first set of constant diameter helical protrusions, having a diameter smaller than the diameter of said first set of threads, on said smaller diameter shank portion between said threads,
a second set of constant diameter threads on said larger diameter shank portion, said second set of threads having a larger diameter than the diameter of said first set of threads, and
a second set of constant diameter helical protrusions, having a diameter smaller than the diameter of said second set of threads, on said larger diameter shank portion between said second threads.
2. A masonry screw anchor according to claim 1, wherein the ratio of thread diameter to protrusion diameter for the large shank portion is equal to the same ratio for the smaller shank portion. .Iadd.
3. A masonry screw anchor comprising:
an elongated shank portion including a smaller constant diameter portion having a pointed end and an adjacent larger diameter portion joined therewith via a tapered portion,
a first set of constant diameter threads on said smaller diameter shank portion,
a first set of constant diameter helical protrusions, having a diameter smaller than the diameter of said first set of threads, on said smaller diameter shank portion between said threads, and
a second set of constant diameter threads on said larger diameter shank portion, said second set of threads having a larger diameter than the diameter of said first set of threads. .Iaddend. .Iadd.
4. A masonry screw anchor according to claim 3 further comprising a second set of constant diameter helical protrusions positioned on said larger diameter shank portion between said second set of constant diameter threads. .Iaddend. .Iadd.5. A masonry screw anchor comprising:
an elongated shank portion including a lower portion having a pointed end and an adjacent upper portion joined therewith,
a first set of constant diameter threads on said lower shank portion,
a first set of constant diameter helical protrusions, having a diameter smaller than the diameter of said first set of threads, on said lower shank portion between said threads, and
a second set of constant diameter threads on said upper shank portion, said second set of threads having a larger diameter than the diameter of said first set of threads. .Iaddend. .Iadd.6. A masonry screw anchor according to claim 5 further comprising a second set of constant diameter helical protrusions positioned on said upper shank portion between said second set
of constant diameter threads. .Iaddend. .Iadd.7. A masonry screw anchor according to claim 5 or 6 wherein said upper portion of the shank has a larger diameter than the lower portion. .Iaddend. .Iadd.8. A masonry screw anchor according to claim 7 wherein said upper portion of the shank is joined with said lower portion via a tapered portion. .Iaddend.
Description

The present invention relates generally to an anchor device which is designed to be secured within a bore formed in a masonry structure.

A state of the art anchor device is disclosed in U.S. Pat. No. 4,657,460. That anchor is formed with a sharp helical thread which has a tapering crest diameter which decreases from the trailing extremity of the shank to the entering extremity. Notches formed on the crests of the helical thread provide a means for allowing the helical thread to become firmly embedded in the side walls of the bore hole. A series of helical protrusions are spaced along the shank which provide a means of guiding the screw.

One of the problems with this type anchor design is that the tapered thread acts like a wedge. The deeper it is driven the higher the drive torque to install and this can lead to premature breakage of the screw during installation.

Another negative of this design, which is formed by roll forming dies, is that since the threads are tapered special roll forming dies must be used.

It is accordingly an object of the present invention to provide an effective masonry screw which can be manufactured using commercially available roll form dies to form the threads. This will allow for more control of tolerances pertaining to thread diameter and would also contribute to longer die life.

It is the object of the present invention to provide a masonry anchor which will require a low driving torque but will still provide good resistance to pullout and shear.

Another object of this invention is to provide a screw which has high torsional resistance to minimize breakage that can occur during installation.

Other objects and advantages of the present invention will become apparent from the following portion of the specification and drawings which indicate in accordance with the mandate of the patent which statutes a presently preferred embodiment incorporating the principles of the invention.

REFERRING TO THE DRAWINGS

FIG. 1 is a side elevational view of an anchor device made in accordance with the teachings of the present invention embedded in a masonry like structure; and

FIG. 2 is an enlarged partial elevation view of a portion of the anchor device shown in FIG. 1.

The masonry screw (10) as illustrated in FIG. 1 is shown with a large head section (12) with appropriate rotation inducing surfaces (14) and an elongated shank (16) with a substantially pointed entering extremity (18). A first set of constant diameter D1, somewhat flat crested helical threads (19) are formed along the constant diameter D2 length L1 of the shank providing a first set of helical protrusions. A second set of constant diameter D3 sharp crested helical threads (20) having a larger diameter than the crest diameter D1 of the first set of threads 19 is formed on the upper length L2 of the shank which has a uniform diameter D2 which is greater than the diameter D2 of the lower shank portion. Spaced between the adjacent protrusions of the first set of threads 19 is a set of helical protrusions (22). The threads (19) and the helical protrusions (22) will have approximately the same pitch and the crest diameter D1, D2 of the thread (19) will be greater than the radial dimension of the helical protrusion (22). Similarly spaced between the adjacent protrusions of the second set of threads 20 is a set of helical protrusions (23) which will have the same pitch as the second set of threads and will have a diameter D6 slightly smaller than the crest diameter D3 of the second set of threads.

The crest diameter of the screw anchor is tapered or stepped 30 as indicated in FIG. 2 to merge the smaller diameter shank portion D2 with the larger diameter portion D4 and the ratio of large crest diameter D3 to large helical protrusions diameter D6 is the same as the ratio of small crest diameter D1 to small helical protrusions diameter D5.

The masonry like structure (28) is provided with a bore (30) through the use of a conventional masonry drilling device. One of the advantages of the present invention is that the fixture to be attached (32) may be positioned on the support structure and provided with an aperture (33) during the drilling operation. When the fixture and structure has been prepared the anchor device (10) is inserted in the bore (30) utilizing fastener drilling apparatus.

As the anchor device (10) is rotated and axially inserted into the bore, the relatively flat crests of the lead thread (19) form threads into the concrete and are embedded into the side walls of the bore. As the device is driven deeper the upper threaded portion (20) having the sharp crested larger diameter threads further engages the threads in the concrete formed by the lower threads (19). The included angle of the threads (19) and (20) are approximately 30 degrees to facilitate the embedment. The radial protrusions (22), (23) which are of a smaller diameter than the bore aid in centering and guiding the device into the bore without adding additional torsional stress during initial installation.

Patent Citations
Cited PatentFiling datePublication dateApplicantTitle
US1980093 *May 13, 1925Nov 6, 1934Rosenberg HeymanAnchorage device
US3207023 *Sep 4, 1964Sep 21, 1965Illinois Tool WorksScrew fastener
US3703843 *Jan 4, 1971Nov 28, 1972Msl Ind IncFastener with improved thread construction
US3861269 *Nov 13, 1972Jan 21, 1975Superior Dry Wall Screw Mfg CoFastener with improved thread construction
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FR43329E * Title not available
Referenced by
Citing PatentFiling datePublication dateApplicantTitle
US5743914 *Jun 6, 1996Apr 28, 1998Skiba; Jeffry B.Bone screw
US5779417 *May 12, 1997Jul 14, 1998Illinois Tool Works Inc.Fastener having primary and secondary threads
US6322307 *Jul 27, 1998Nov 27, 2001Unifix LimitedFixing anchor
US6419435Jul 11, 2000Jul 16, 2002Paul GaudronWedging masonry anchor bolt and sleeve anchor for masonry bolt used in cinder blocks
US6743233Aug 2, 2000Jun 1, 2004Orthopaedic Biosystems, Ltd., Inc.Medical screw and method of installation
US6899500Jun 19, 2001May 31, 2005Illinois Tool Works Inc.Fastner having multiple-bossed lead
US6918727 *Jan 14, 2004Jul 19, 2005Joker Industrial Co., Ltd.Anchoring screw with double heads and triple threads of different depths of thread
US6956181Oct 14, 2003Oct 18, 2005Illinois Tool Works, Inc.Method for making a fastener
US6957557Jan 31, 2005Oct 25, 2005Illinois Tool Works Inc.Threaded fastener with dual reinforcing leads for facilitating manufacture of the fastener, thread rolling die for forming the threaded fastener, and method of manufacturing the threaded fastener
US7070376 *Aug 9, 2000Jul 4, 2006Simpson Strong-Tie Company, Inc.Self-drilling, self-anchoring fastener for concrete
US7076989Jan 31, 2005Jul 18, 2006Illinois Tool Works Inc.Threaded fastener with dual reinforcing leads for facilitating manufacture of the fastener, thread rolling die for forming the threaded fastener, and method of manufacturing the threaded fastener
US7090453 *Dec 27, 2004Aug 15, 2006Teng-Hung LinScrew
US7101134Mar 12, 2002Sep 5, 2006Illinois Tool Works Inc.Fastener having multiple lobed thread
US7156600May 13, 2004Jan 2, 2007Illinois Tool Works Inc.Die for, method of making, and fastener with lobed primary thread lead and interposed dual auxiliary thread lead with improved substrate entry end portion
US7458759Dec 18, 2002Dec 2, 2008Illinois Tool Works Inc.Threaded fastener with dual reinforcing leads for facilitating manufacture of the fastener, thread rolling die for forming the threaded fastener, and method of manufacturing the threaded fastener
US7780388 *Jul 21, 2005Aug 24, 2010Topura Co., Ltd.Tapping screw
US8511957Apr 28, 2008Aug 20, 2013Illinoks Tool Works Inc.Fastener for stucco or hard board substrates
US20110295282 *Mar 29, 2011Dec 1, 2011Tyco Healthcare Group LpFastener and drive method for soft tissue repair
WO1997046167A1 *Jun 6, 1997Dec 11, 1997Orthopaedic Biosystems Ltd IncBone screw
Classifications
U.S. Classification411/412, 411/386, 411/426
International ClassificationF16B13/02, F16B25/00
Cooperative ClassificationF16B25/00, F16B25/0047, F16B25/0068, F16B25/0026, F16B13/02
European ClassificationF16B25/00C3, F16B25/00G1D, F16B25/00G1A, F16B13/02, F16B25/00
Legal Events
DateCodeEventDescription
Nov 26, 2002ASAssignment
Owner name: NEWFREY LLC, DELAWARE
Free format text: CHANGE OF NAME;ASSIGNOR:EMHART LLC;REEL/FRAME:013516/0757
Effective date: 20021030
Owner name: NEWFREY LLC 1423 KIRKWOOD HIGHWAYNEWARK, DELAWARE,
Free format text: CHANGE OF NAME;ASSIGNOR:EMHART LLC /AR;REEL/FRAME:013516/0757
Apr 18, 2002ASAssignment
Owner name: EMHART LLC, DELAWARE
Free format text: CHANGE OF NAME;ASSIGNOR:EMHART INC.;REEL/FRAME:013036/0919
Effective date: 20011029
Owner name: EMHART LLC 1423 KIRKWOOD HWY NEWARK DELAWARE 19711
Owner name: EMHART LLC 1423 KIRKWOOD HWYNEWARK, DELAWARE, 1971
Free format text: CHANGE OF NAME;ASSIGNOR:EMHART INC. /AR;REEL/FRAME:013036/0919