Screw anchoring bushing for use in semihard materials

• US 4,610,589 A
• Filed: 06/18/1984
• Issued: 09/09/1986
• Est. Priority Date: 09/20/1977
• Status: Expired due to Fees

• Current Assignee: Tri-Bolt Fasteners APS
• Original Assignee: Tri-Bolt Fasteners APS
• Inventors: Bredal, Torben
• Primary Examiner(s): Smith, Gary L.
• Assistant Examiner(s): WILSON, NEILL R
• Application Number:
  US06/621,465
• Time in Patent Office: 813 Days
• Field of Search: 411/60, 411/61, 411/57, 411/74, 411/71, 411/73, 411/72, 411/177, 411/179, 411/180, 411/183, 411/463, 411/466, 411/520, 411/521, 411/528, 411/529, 411/107, 411/395, 411/508-51 0
• US Class Current: 411/180
• CPC Class Codes: F16B 13/0866 with prongs penetrating into the wall of the hole by a retractile movement of a threaded member
• CPC Class Codes: F16B 19/004 made in one piece F16B21/084 takes precedence

Abstract

A screw anchoring plug or bushing for use in predrilled mounting holes in elements of semihard materials such as chipboard, consisting of a sleeve made as a rolled up piece of metal sheet material provided with a number of slightly projecting barb-like tongue portions and cured to be resilient, whereby the tongue portions project as leaf springs. The sleeve is threaded for direct engagement with a standard screw, and when it is inserted in the mounting hole and the ends of the tongue portions are hereby caused to resiliently engage the wall of the hole, the sleeve will thereafter be moved axially outwardly when the screw is tightened, and the tongues will cut themselves into the hole wall and get spread to resist further retraction of the sleeve.

Claims

1. In a screw anchoring bushing of the type for use in elements of a semihard material such as chipboard, consisting of a substantially cylindrical metal sleeve body for insertion in a predrilled mounting hole in said element and threaded for cooperation with a tightening screw member, said sleeve body being provided with axially extending tongue portions operable to be swung outwardly in a barb-like manner in response to tightening of said screw member so as to intrude into the wall of the mounting hole and thereby obstruct retraction of the sleeve body, the improvement wherein the sleeve body is a threaded metal sheet member of pronounced material resiliency rolled through substantially 360°

so as to bring opposite edges thereof into a mutually adjacent position, said tongue portions being provided as barbs bent outwardly from the sleeve body so as to be resiliently depressable inwardly towards the cylindric surface of the sleeve body, and wherein said edges are provided with axially extending outwardly bent edge strip portions which are operable to self-cut an axial receiving groove in the surface of said hole during insertion of said sleeve body into said hole so as to thereafter form a means for restricting both rotation of said sleeve body and opening expansion of said sheet member, whereby anchoring of said sleeve body is achieved essentially through spreading of said tongue portions during axial displacement of said sleeve body during tightening of said screw member.

2. An anchoring bushing according to claim 1, wherein said edge strip portions have outer parallelly disposed oppositely facing surfaces for engaging walls of said receiving groove to prevent said rotation and opening expansion.

3. An anchoring bushing for use in elements of a semihard material such as chipboard, consisting of a substantially cylindrical metal sleeve body for insertion in a predrilled mounting hole in said element and threaded for cooperation with a tightening screw member, said sleeve body being provided with axially extending tongue portions operable to be swung outwardly in a barb-like manner in response to tightening of said screw member so as to intrude into the wall of the mounting hole and thereby obstruct retraction of the sleeve body, said tongue portions having free ends directed toward a front end of the sleeve body that is outermost located in use, characterized in that the sleeve body is made as a rolled up and threaded metal sheet member of pronounced material resiliency, said tongue portions being provided as barbs bent outwardly from the sleeve body so as to be resiliently depressable inwardly towards the cylinder surfaces of the sleeve body, and in that the tightening screw member is in the shape of a threaded nut and the rolled up sheet member is provided with an exterior threading adjacent said front end, for cooperation with said nut shaped tightening screw member.

4. An anchoring bushing for use in elements of a semihard material such as chipboard. consisting of a substantially cylindrical metal sleeve body for insertion in a predrilled mounting hole in said element and threaded for cooperation with a tightening screw member, said sleeve body being provided with axially extending tongue portions extending from the body toward a first front end thereof, that is outermost located in use, and operable to be swung outwardly in a barblike manner in response to tightening of said screw member so as to intrude into the wall of the mounting hole and thereby obstruct retraction of the sleeve body, characterized in that the sleeve body is made as a rolled up and threaded metal sheet member of pronounced material resiliency, said tongue portions being provided as barbs bent outwardly from the sleeve body so as to be resiliently depressable inwardly towards the cylindric surface of the sleeve body, and in that at least some of the said tongue or barb portions are provided between axial incisions in an exterior folded edge portion of a second rear end of the sleeve body, which is innermost located in use.

5. A screw anchoring assembly for use in predrilled holes in construction elements of a semihard material, comprising a mounting screw, having a threaded operative stem portion, and a generally cylindrical anchoring bushing, said anchoring bushing being internally threaded for effective screwing cooperation with said mounting screw stem portion and consisting of a sheet of rigid spring metal rolled into a sleeve member, said sleeve member having integrally formed therein a number of barb-like tongues which are bent outwardly from the sleeve member so as to be resiliently depressable inwardly towards a cylindrical outer surface of the sleeve member as well as being outwardly pivotable away therefrom, and said sleeve member being rolled up such that longitudinally extending edge portions thereof abut each other so as to thereby define an operative diameter of the bushing that is coordinated to that of the threading of the screw stem portion for ensuring a free and nonexpansive screwability of the screw along the internal threading of the bushing, at least one of the abutting edge portions being provided with an outwardly projecting rib portion.