Tamper-resistant fastener

Patent metadata

Field	Value
Publication number	US-10968942-B1
Application number	US-201816166463-A
Country	US
Kind code	B1
Filing date	Oct 22, 2018
Priority date	Oct 22, 2018
Publication date	Apr 6, 2021
Grant date	Apr 6, 2021

Abstract

A tamper-resistant threaded fastener including a circular head having a slot formed in the head transverse to the longitudinal axis, the slot having an enlarged region intermediate an apex and a base of the slot. A cap member includes a head having a drive feature formed therein, the head extending to a first shank portion, extending to an enlarged second shank portion, extending to a foot. The cap member is insertable in the slot only from a direction transverse to the longitudinal axis. During rotational installation of the fastener and cap member in a threaded counterbored opening for securing a barrier for protecting an asset, the foot shears inside the slot at a predetermined rotational drive force, the cap member being rotatable in the opening and protectively covering the fastener head.

First claim

What is claimed is:

1. A tamper-resistant fastener, comprising:
a threaded fastener including a head that is circular and having a first longitudinal axis, the threaded fastener having a slot formed at least in the head of the threaded fastener transverse to the first longitudinal axis, the slot extending from a base through an end of the head of the threaded fastener opposite a shank of the threaded fastener at an apex of the slot, the slot having an enlarged region intermediate the apex and the base; and
a cap member having a second longitudinal axis and comprising a head having a drive feature formed therein, the head of the cap member extending along the second longitudinal axis to a first shank portion extending along the second longitudinal axis to an enlarged second shank portion extending along the second longitudinal axis to an end portion extending along the second longitudinal axis to a foot extending transverse to the second longitudinal axis;
wherein the cap member is insertable in the slot only from a direction transverse to the first longitudinal axis of the threaded fastener, the head of the cap member extendable over the head of the threaded fastener, the enlarged second shank portion receivable in the enlarged region, and the foot receivable in the slot between the enlarged region and the base;
wherein in response to insertion of the cap member in the slot of the threaded fastener, and the shank of the threaded fastener alignedly positioned in a threaded counterbored opening for securing a barrier for protecting an asset, and application of a rotational drive force to the drive feature of the cap member, the foot abutting the slot and preventing rotation of the cap member relative to the slot, thereby urging the threaded fastener to threadedly engage the threaded counterbored opening until the end portion shearing at a predetermined rotational drive force, the cap member being rotatable in the threaded counterbored opening and protectively covering the head of the threaded fastener, the cap member not being removable from the slot in a direction away from the threaded fastener along the first longitudinal axis of the threaded fastener.

2. The tamper-resistant fastener of claim 1 , wherein the drive feature is taken from the group consisting of openings receivable by a spanner wrench, a square opening, a hexagonal opening, a slot, a one-way slot arrangement, a cruciform opening, a triangular opening, a pentagon, a star, a hexalobe, a tri-lobe, or combination thereof.

3. The tamper-resistant fastener of claim 1 , wherein the head of the cap member includes an aperture transverse to the second longitudinal axis.

4. The tamper-resistant fastener of claim 3 , wherein the aperture extends through a central portion of the head of the cap member.

5. The tamper-resistant fastener of claim 1 further comprises an insert for insertion in the drive feature.

6. The tamper-resistant fastener of claim 5 , wherein the insert is composed of the group consisting of ceramics, metals, composites, material having a Vickers hardness number of 500 HV, or combination thereof.

7. The tamper-resistant fastener of claim 5 further comprises at least one additional insert positioned in a corresponding recess not associated with the drive feature.

8. The tamper-resistant fastener of claim 7 , wherein the at least one additional insert does not intersect a centered portion of the head of the cap member in a direction parallel to the second longitudinal axis, the centered portion including an aperture formed in the head of the cap member transverse to the second longitudinal axis.

9. A tamper-resistant system, comprising:
a threaded fastener including a head that is circular and having a first longitudinal axis, the threaded fastener having a slot formed at least in the head of the threaded fastener transverse to the first longitudinal axis, the slot extending from a base through an end of the head of the threaded fastener opposite a shank of the threaded fastener at an apex of the slot, the slot having an enlarged region intermediate the apex and the base; and
a cap member having a second longitudinal axis and comprising a head having a drive feature formed therein, the head of the cap member extending along the second longitudinal axis to a first shank portion extending along the second longitudinal axis to an enlarged second shank portion extending along the second longitudinal axis to an end portion extending along the second longitudinal axis to a foot extending transverse to the second longitudinal axis;
wherein the cap member is insertable in the slot only from a direction transverse to the first longitudinal axis of the threaded fastener, the head of the cap member extendable over the head of the threaded fastener, the enlarged second shank portion receivable in the enlarged region, and the foot receivable in the slot between the enlarged region and the base; and
a barrier for protecting an asset;
wherein in response to insertion of the cap member in the slot of the threaded fastener, and the shank of the threaded fastener alignedly positioned in a threaded counterbored opening for securing the barrier, and application of a rotational drive force to the drive feature of the cap member, the foot abutting the slot and preventing rotation of the cap member relative to the slot, thereby urging the threaded fastener to threadedly engage the threaded counterbored opening until the end portion shearing at a predetermined rotational drive force, the cap member being rotatable in the threaded counterbored opening and protectively covering the head of the threaded fastener, the cap member not being removable from the slot in a direction away from the threaded fastener along the first longitudinal axis of the threaded fastener.

10. The tamper-resistant system of claim 9 , wherein the head of the cap member includes an aperture transverse to the second longitudinal axis.

11. The tamper-resistant system of claim 10 , wherein the aperture extends through a central portion of the head of the cap member.

12. The tamper-resistant system of claim 9 further comprises an insert for insertion in the drive feature.

13. The tamper-resistant system of claim 12 further comprises at least one additional insert positioned in a corresponding recess not associated with the drive feature.

14. The tamper-resistant system of claim 13 , wherein the at least one additional insert does not intersect a centered portion of the head of the cap member in a direction parallel to the second longitudinal axis, the centered portion including an aperture formed in the head of the cap member transverse to the second longitudinal axis.

15. The tamper-resistant system of claim 9 , wherein a counterbored portion of the threaded counterbored opening is formed in a counterbored receiving member overlying a remaining portion of the threaded counterbored opening.

16. The tamper-resistant system of claim 15 , wherein the counterbored receiving member resembles a truncated circular cone.

17. The tamper-resistant system of claim 10 , wherein the barrier includes a receiving feature extending through opposed lateral portions of the threaded counterbored opening for receiving a tamper-evident elongated member through the receiving feature of the barrier and the aperture of the inserted cap member.

18. The tamper-resistant system of claim 17 , wherein the receiving feature extends through opposed lateral portions of at least two threaded counterbored openings for receiving the tamper-evident elongated member through at least

Assignees

• Nat Tech & Eng Solutions Sandia Llc

Inventors

• Neidigk Stephen
• Wilson Zachary Medaris

Classifications

• F16B41/005 Primary

  Measures against unauthorised operation of bolts, nuts or pins (F16B23/0007, F16B23/0061, F16B23/0069, F16B23/0076 and F16B31/02 take precedence; locks, keys E05B; for valves, taps or cocks F16K35/00; for pipe-joints with swivel-nuts F16L19/005) · CPC title

• F16B37/14

  Cap nuts; Nut caps or bolt caps · CPC title

• F16B35/06

  Specially-shaped heads (special shape in order to rotate the bolt F16B23/00 {; separate hook adaptors for bolts F16B43/025}) · CPC title

• F16B5/02

  by means of fastening members using screw-thread ({F16B5/0004 takes precedence}; construction of screw-threaded connections F16B25/00 - F16B39/00) · CPC title

• F16B37/042

  locking by rotation · CPC title