US3912116A - Tamper-resisting screw-threaded plug - Google Patents

Tamper-resisting screw-threaded plug Download PDF

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Publication number
US3912116A
US3912116A US499943A US49994374A US3912116A US 3912116 A US3912116 A US 3912116A US 499943 A US499943 A US 499943A US 49994374 A US49994374 A US 49994374A US 3912116 A US3912116 A US 3912116A
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Prior art keywords
sleeve
main body
plug
recess
tool
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Expired - Lifetime
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US499943A
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William Chahley
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WM CHAHLEY Ltd
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WM CHAHLEY Ltd
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    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F16—ENGINEERING ELEMENTS AND UNITS; GENERAL MEASURES FOR PRODUCING AND MAINTAINING EFFECTIVE FUNCTIONING OF MACHINES OR INSTALLATIONS; THERMAL INSULATION IN GENERAL
    • F16B—DEVICES FOR FASTENING OR SECURING CONSTRUCTIONAL ELEMENTS OR MACHINE PARTS TOGETHER, e.g. NAILS, BOLTS, CIRCLIPS, CLAMPS, CLIPS OR WEDGES; JOINTS OR JOINTING
    • F16B23/00—Specially shaped nuts or heads of bolts or screws for rotations by a tool
    • F16B23/0061—Specially shaped nuts or heads of bolts or screws for rotations by a tool with grooves, notches or splines on the external peripheral surface designed for tools engaging in radial direction

Definitions

  • a tamper-resisting screw-threaded plug includes a cylindrical main body with a screw-threaded outer side wall.
  • the body has an annular recess in the front face which is bounded on its radially outer side by a peripheral wall of the main boyd and on its radially inner side by a central hub of the main body.
  • the hub is shaped for engagement by a correct tool of predetermined shape to enable the plug to be rotated by the tool.
  • the plug also includes a sleeve secured in the recess adjacent the peripheral wall of the main body so as to be rotatable relative thereto, the sleeve being radially spaced from the central hub to enable the tool to be engaged therewith.
  • the sleeve has an outwardly directed annular flange extending over a front face of the peripheral wall of the main body to prevent engagement of the front face by an incorrect tool.
  • Patent TAMPER-RESISTING SCREW-THREADED PLUG This invention relates to tamper-resisting screwthreaded plugs, that is to say. plugs which are constructed to resist'removal by unauthorized persons.
  • Such a plug can be constructed so that it is removable by an authorized person with a specially shaped correct tool, but is resistant to removal by an unauthorized person with a tool, such as a common tool, of some other shape.
  • a plug includes a cylindrical main body with a'screw-threaded outer side wall, the body having an annular recess in its front face, the annular recess being bounded on its radially outer side by a peripheral wall and on its radially inner side by a central hub, the hub being shaped for engagement by a correct tool of predetermined shape to enable the plug to be rotated by the tool, the plug also including a sleeve secured in the recess adjacent the peripheral wall of the body so as to be rotatable relative to the body, the sleeve being spaced from the central hub to enable the tool to be engaged therewith, and the sleeve having an outwardly directed annular flange extending over the front face of the peripheral wall of the body.
  • the plug cannot be rotated for removal from a screw-threaded aperture by a tool engaging the peripheral wall of the body, since the peripheral wall is protected by the sleeve and its flange. Rotation of the sleeve and its flange by a tool does not rotate the main body of the nut.
  • the main body of the nut can only by rotated by a tool engaging the central hub.
  • the hub may be cylindrical, so as to resist rotation by tools such as pliers, and may have a plurality of longitudinally extending grooves for engagement by an appropriately shaped correct removal tool.
  • the forward ends of the grooves may be laterally flared, so as to form a further bar to engagement by tools other than the correct tool.
  • the periphery of the hub may be chamfered as a further bar to unauthorized removal.
  • the body recess may contain a retaining ring tightly engaging the peripheral wall and spaced from the bot tom of the recess, the sleeve having a groove in its outer surface, the groove containing a spring clip engaging the rear end of the retaining ring to retain the sleeve in the recess, while allowing relative rotation between the sleeve and the main body.
  • the sleeve may also have an inwardly directed annular flange within the recess, adjacent the bottom thereof, so as to prevent engagement of the bottom of the recess by a tool. 7
  • FIG. 1 is a sectional side view of a plug
  • FIG. 2 is a front view of a plug
  • FIG. 3 is a side view of a correct too] for use with the P g
  • FIG. 4 is a front view of the tool
  • FIG. 5 is a sectional side view showing the tool engaged with the plug.
  • the plug has a cylindrical main body 11 with a screw-threaded outer side wall 12.
  • the body 11 has an annular recess 13 in its front face 14, recess 13 being bounded on its radially outer side by a peripheral wall 15 and on its radially inner side by a central hub 16.
  • the recess 13 contains a retaining ring 17 which is a press fit with theperipheral wall 15, so as to be fixed thereto.
  • the front end of the ring 17 is flush with the front face l4 of the body ll, and the rear end of the ring 17 is spaced from the bottom of the recess 13.
  • a sleeve 18 is located. in the recess 13, and is a loose fit in the retaining ring so as to be rotatable relative thereto.
  • sleeve 18 extends for the whole depth of the recess 13.
  • the sleeve 18 has an annular groove in its outer wall which contains a spring clip 19.
  • the clip 19 projects from the groove and is engaged behind the rear end of the retaining ring 17, so that the retaining ring 17 retains the sleeve 18 in the recess 13, while allowing the sleeve 18 to be-capable of rotation relative to the retaining ring 17 and the main body 1 1 of the plug.
  • the sleeve 18 has a radially outwardly directed annular flange 21 at its front end extending across the front face of the peripheral wall 15, and also has a radially inwardly directed annular flange 22 at its rear end extending across the bottom of the recess 13.
  • Two drain holes 23 extend from the bottom of the recess 13 to the rear face of the plug.
  • the hub 16 is cylindrical, and has three equiangularly spaced longitudinally extending grooves 24, which extend for the full length of the hub 16.
  • the front end of each groove 24 is flared laterally outwardly at 25, and the periphery of the hub 16 is chamfered at 20.
  • a correct tool for use with the plug has a tubular body 26 with three radially-inwardly extending fingers 27 at one end.
  • the fingers 27 are positioned and shaped for engagement in the grooves 24 of the hub 16.
  • the tool fingers 27 are slid into the hub grooves 24. The tool is then rotated by any suitable other instrument.
  • the outer sleeve flange 21 protects the front face of the peripheral wall of the main body 1 1 from any screwdriver or chisel hammer blows, which may be applied in an attempt to rotate the plug or create indentations for future rotation attempts.
  • the sleeve flange 21 will merely rotate relative to the body 1 1 under such blows.
  • the inner flange 22 similarly protects the bottom of the recess 13.
  • the hub 16 cannot be effectively grasped by such tools as pliers or vice grips, particularly in view of the chamfer 20. If any chisel or screwdriver attempt is made to turn the hub 16, the flaring 25 facilitates shearing of the front end portion of the hub 16, thereby rendering such attempts ineffective. In any event, the hub 16 is of too small a diameter to enable any effective turning movement to be applied thereto by a chisel or screwdriver.
  • a tamper-resisting screw-threaded plug including a cylindrical main body with a screw-threaded outer side wall, the body having an annular recess in the front face thereof, the annular recess being bounded on its radially outer side by a peripheral wall of the main body and on its radially inner side by a central hub of the main body, the hub being shaped for engagement by a correct tool of predetermined shape to enable the plug to be rotated by the tool, the plug also including a sleeve secured in the recess adjacent the peripheral wall of the main body so as to be rotatable relative thereto, the sleeve being radially spaced from the central hub to enable the tool to be engaged therewith, the sleeve having an outwardly directed annular flange extending over a front face of the peripheral wall of the main body to prevent engagement of said front face by an incorrect tool.
  • a plug according to claim 1 wherein the sleeve also has an inwardly directed annular flange within the recess and adjacent the bottom thereof.
  • a plug according to claim 1 including a retaining ring within the recess and tightly engaging the peripheral wall, the retaining ring being spaced from the bottom of the recess, the sleeve having a groove in its outer surface, and the groove containing a spring clip engaging a rear end of the retaining ring to secure the sleeve in the recess, while allowing relative rotation between the sleeve and the main body.

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  • Engineering & Computer Science (AREA)
  • General Engineering & Computer Science (AREA)
  • Mechanical Engineering (AREA)
  • Dowels (AREA)
  • Reinforcement Elements For Buildings (AREA)
  • Joining Of Building Structures In Genera (AREA)

Abstract

A tamper-resisting screw-threaded plug includes a cylindrical main body with a screw-threaded outer side wall. The body has an annular recess in the front face which is bounded on its radially outer side by a peripheral wall of the main boyd and on its radially inner side by a central hub of the main body. The hub is shaped for engagement by a correct tool of predetermined shape to enable the plug to be rotated by the tool. The plug also includes a sleeve secured in the recess adjacent the peripheral wall of the main body so as to be rotatable relative thereto, the sleeve being radially spaced from the central hub to enable the tool to be engaged therewith. The sleeve has an outwardly directed annular flange extending over a front face of the peripheral wall of the main body to prevent engagement of the front face by an incorrect tool.

Description

[ Oct. 14, 1975 [54] TAMPER-RESISTING SCREW-THREADED PLUG [75] Inventor: William Chahley, Saint John,
'Canada [73] Assignee: Wm. Chahley Ltd., Saint John,
Canada 22 Filed: Aug. 23, 1974 21 Appl. No.: 499,943
[30] Foreign Application Priority Data Mar. 27, 1974 Canada 196136 [52] US. Cl 220/288; 220/284 [51] Int. Cl. B65D 41/04 [58] Field of Search 220/284, 288, 298, 301, 220/304, 307; 138/96 R, 89
[56] References Cited UNITED STATES PATENTS 1,422,342 7/1922 Darling 220/284 1,712,361 5/1929 Soderquist. 220/284 2,663,451 12/1953 Yarnall 220/284 2,801,022 7/1957 Evenb1is.. 220/288 3,195,762 7/1965 Senoff 220/284 3,380,618 4/1968 vPhillips 220/284 Primary ExaminerWilliam 1. Price Assistant ExaminerR. E. Hart Attorney, Agent, or FirmBrowne, Beveridge, DeGrandi & Kline [57] ABSTRACT A tamper-resisting screw-threaded plug includes a cylindrical main body with a screw-threaded outer side wall. The body has an annular recess in the front face which is bounded on its radially outer side by a peripheral wall of the main boyd and on its radially inner side by a central hub of the main body. The hub is shaped for engagement by a correct tool of predetermined shape to enable the plug to be rotated by the tool. The plug also includes a sleeve secured in the recess adjacent the peripheral wall of the main body so as to be rotatable relative thereto, the sleeve being radially spaced from the central hub to enable the tool to be engaged therewith. The sleeve has an outwardly directed annular flange extending over a front face of the peripheral wall of the main body to prevent engagement of the front face by an incorrect tool.
6 Claims, 5 Drawing Figures Oct. 14, 1975 US. Patent TAMPER-RESISTING SCREW-THREADED PLUG This invention relates to tamper-resisting screwthreaded plugs, that is to say. plugs which are constructed to resist'removal by unauthorized persons.
There are many situations where such plugsa're required to be resistant to removal by unauthorized persons, but nevertheless capable of removal by authorized persons. Such a plug can be constructed so that it is removable by an authorized person with a specially shaped correct tool, but is resistant to removal by an unauthorized person with a tool, such as a common tool, of some other shape. I
It is therefore an object of the invention: to provide an improved plug of this kind. I
According to the invention, a plug includes a cylindrical main body with a'screw-threaded outer side wall, the body having an annular recess in its front face, the annular recess being bounded on its radially outer side by a peripheral wall and on its radially inner side by a central hub, the hub being shaped for engagement by a correct tool of predetermined shape to enable the plug to be rotated by the tool, the plug also including a sleeve secured in the recess adjacent the peripheral wall of the body so as to be rotatable relative to the body, the sleeve being spaced from the central hub to enable the tool to be engaged therewith, and the sleeve having an outwardly directed annular flange extending over the front face of the peripheral wall of the body.
Thus, the plug cannot be rotated for removal from a screw-threaded aperture by a tool engaging the peripheral wall of the body, since the peripheral wall is protected by the sleeve and its flange. Rotation of the sleeve and its flange by a tool does not rotate the main body of the nut. The main body of the nut can only by rotated by a tool engaging the central hub.
The hub may be cylindrical, so as to resist rotation by tools such as pliers, and may have a plurality of longitudinally extending grooves for engagement by an appropriately shaped correct removal tool. The forward ends of the grooves may be laterally flared, so as to form a further bar to engagement by tools other than the correct tool. Also, the periphery of the hub may be chamfered as a further bar to unauthorized removal.
The body recess may contain a retaining ring tightly engaging the peripheral wall and spaced from the bot tom of the recess, the sleeve having a groove in its outer surface, the groove containing a spring clip engaging the rear end of the retaining ring to retain the sleeve in the recess, while allowing relative rotation between the sleeve and the main body.
The sleeve may also have an inwardly directed annular flange within the recess, adjacent the bottom thereof, so as to prevent engagement of the bottom of the recess by a tool. 7
One embodiment of the invention will now be described, by way of example, with reference to the accompanying drawings, of which:
FIG. 1 is a sectional side view of a plug,
FIG. 2 is a front view of a plug,
FIG. 3 is a side view of a correct too] for use with the P g FIG. 4 is a front view of the tool, and
FIG. 5 is a sectional side view showing the tool engaged with the plug.
Referring to the drawings, the plug has a cylindrical main body 11 with a screw-threaded outer side wall 12.
The body 11 has an annular recess 13 in its front face 14, recess 13 being bounded on its radially outer side by a peripheral wall 15 and on its radially inner side by a central hub 16.
The recess 13 contains a retaining ring 17 which is a press fit with theperipheral wall 15, so as to be fixed thereto. The front end of the ring 17 is flush with the front face l4 of the body ll, and the rear end of the ring 17 is spaced from the bottom of the recess 13. A sleeve 18 is located. in the recess 13, and is a loose fit in the retaining ring so as to be rotatable relative thereto. sleeve 18 extends for the whole depth of the recess 13. The sleeve 18 has an annular groove in its outer wall which contains a spring clip 19. The clip 19 projects from the groove and is engaged behind the rear end of the retaining ring 17, so that the retaining ring 17 retains the sleeve 18 in the recess 13, while allowing the sleeve 18 to be-capable of rotation relative to the retaining ring 17 and the main body 1 1 of the plug.
The sleeve 18 has a radially outwardly directed annular flange 21 at its front end extending across the front face of the peripheral wall 15, and also has a radially inwardly directed annular flange 22 at its rear end extending across the bottom of the recess 13. Two drain holes 23 extend from the bottom of the recess 13 to the rear face of the plug.
The hub 16 is cylindrical, and has three equiangularly spaced longitudinally extending grooves 24, which extend for the full length of the hub 16. The front end of each groove 24 is flared laterally outwardly at 25, and the periphery of the hub 16 is chamfered at 20.
A correct tool for use with the plug has a tubular body 26 with three radially-inwardly extending fingers 27 at one end. The fingers 27 are positioned and shaped for engagement in the grooves 24 of the hub 16. To insert the plug in, or remove it from, a screwthreaded aperture of appropriate size, the tool fingers 27 are slid into the hub grooves 24. The tool is then rotated by any suitable other instrument.
To rotate the plug, it is necessary to have the correct tool. Common tools cannot easily be used to turn the plug. For example, the outer sleeve flange 21 protects the front face of the peripheral wall of the main body 1 1 from any screwdriver or chisel hammer blows, which may be applied in an attempt to rotate the plug or create indentations for future rotation attempts. The sleeve flange 21 will merely rotate relative to the body 1 1 under such blows. The inner flange 22 similarly protects the bottom of the recess 13.
Also, the hub 16 cannot be effectively grasped by such tools as pliers or vice grips, particularly in view of the chamfer 20. If any chisel or screwdriver attempt is made to turn the hub 16, the flaring 25 facilitates shearing of the front end portion of the hub 16, thereby rendering such attempts ineffective. In any event, the hub 16 is of too small a diameter to enable any effective turning movement to be applied thereto by a chisel or screwdriver.
It will be seen that the described plug is extremely resistant to unauthorized removal. The described plug is actually intended for use as the closing plug in the manhole cover which is the subject of Canadian Pat. No. 937,089, issued Nov. 20, 1973, but of course the invention is not limited to such use.
The embodiments of the invention in which an exclusive property or privilege is claimed are defined as follows:
1. A tamper-resisting screw-threaded plug including a cylindrical main body with a screw-threaded outer side wall, the body having an annular recess in the front face thereof, the annular recess being bounded on its radially outer side by a peripheral wall of the main body and on its radially inner side by a central hub of the main body, the hub being shaped for engagement by a correct tool of predetermined shape to enable the plug to be rotated by the tool, the plug also including a sleeve secured in the recess adjacent the peripheral wall of the main body so as to be rotatable relative thereto, the sleeve being radially spaced from the central hub to enable the tool to be engaged therewith, the sleeve having an outwardly directed annular flange extending over a front face of the peripheral wall of the main body to prevent engagement of said front face by an incorrect tool.
2. A plug according to claim 1 wherein the hub is cylindrical and has a plurality of longitudinally extending grooves for engagement by the correct tool.
3. A plug according to claim 2 wherein the grooves have forward ends which are laterally flared.
4. A plug according to claim 1 wherein the periphery of the hub is chamfered.
5. A plug according to claim 1 wherein the sleeve also has an inwardly directed annular flange within the recess and adjacent the bottom thereof.
6. A plug according to claim 1 including a retaining ring within the recess and tightly engaging the peripheral wall, the retaining ring being spaced from the bottom of the recess, the sleeve having a groove in its outer surface, and the groove containing a spring clip engaging a rear end of the retaining ring to secure the sleeve in the recess, while allowing relative rotation between the sleeve and the main body.

Claims (6)

1. A tamper-resisting screw-threaded plug including a cylindrical main body with a screw-threaded outer side wall, the body having an annular recess in the front face thereof, the annular recess being bounded on its radially outer side by a peripheral wall of the main body and on its radially inner side by a central hub of the main body, the hub being shaped for engagement by a correct tool of predetermined shape to enable the plug to be rotated by the tool, the plug also including a sleeve secured in the recess adjacent the peripheral wall of the main body so as to be rotatable relative thereto, the sleeve being radially spaced from the central hub to enable the tool to be engaged therewith, the sleeve having an outwardly directed annular flange extending over a front face of the peripheral wall of the main body to prevent engagement of said front face by an incorrect tool.
2. A plug according to claim 1 wherein the hub is cylindrical and has a plurality of longitudinally extending grooves for engagement by the correct tool.
3. A plug according to claim 2 wherein the grooves have forward ends which are laterally flared.
4. A plug according to claim 1 wherein the periphery of the hub is chamfered.
5. A plug according to claim 1 wherein the sleeve also has an inwardly directed annular flange within the recess and adjacent the bottom thereof.
6. A plug according to claim 1 including a retaining ring within the recess and tightly engaging the peripheral wall, the retaining ring being spaced from the bottom of the recess, the sleeve having a groove in its outer surface, and the groove containing a spring clip engaging a rear end of the retaining ring to secure the sleeve in the recess, while allowing relative rotation between the sleeve and the main body.
US499943A 1974-03-27 1974-08-23 Tamper-resisting screw-threaded plug Expired - Lifetime US3912116A (en)

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CA196,136A CA976787A (en) 1974-03-27 1974-03-27 Tamper-resisting screw-threaded plug

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Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4335375A (en) * 1978-02-13 1982-06-15 Schaeffer Daniel D Container for an alarm transmitter adapted for insertion into a wall
US4473169A (en) * 1982-02-22 1984-09-25 Fitzgerald Fitz E Anti-theft plug and fastener
US11506291B2 (en) * 2018-11-27 2022-11-22 Hamilton Sundstrand Corporation Filter retaining plug and tool

Families Citing this family (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4397124A (en) * 1981-06-10 1983-08-09 Kawneer Company, Inc. Glass jacks for doors, windows, walls, etc.
AR021590A3 (en) * 2000-04-28 2002-07-31 At Ing S R L A SAFETY BOLT TO BE OPERATED BY A WRENCH AND DRIVE WRENCH

Citations (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US1422342A (en) * 1919-12-02 1922-07-11 Darling Joseph Bung for tank filling and discharge fittings
US1712361A (en) * 1927-02-17 1929-05-07 Arthur R Soderquist Lock closure for ice bags
US2663451A (en) * 1951-10-10 1953-12-22 Chandler P Yarnall Closure plug
US2801022A (en) * 1951-08-14 1957-07-30 American Flange & Mfg Indicating screw plug for barrels and other containers and sealing means for said plug
US3195762A (en) * 1962-05-16 1965-07-20 Herbert P Senoff Closure plug
US3380618A (en) * 1965-09-01 1968-04-30 Rheem Australia Pty Ltd Plugs for container closures

Patent Citations (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US1422342A (en) * 1919-12-02 1922-07-11 Darling Joseph Bung for tank filling and discharge fittings
US1712361A (en) * 1927-02-17 1929-05-07 Arthur R Soderquist Lock closure for ice bags
US2801022A (en) * 1951-08-14 1957-07-30 American Flange & Mfg Indicating screw plug for barrels and other containers and sealing means for said plug
US2663451A (en) * 1951-10-10 1953-12-22 Chandler P Yarnall Closure plug
US3195762A (en) * 1962-05-16 1965-07-20 Herbert P Senoff Closure plug
US3380618A (en) * 1965-09-01 1968-04-30 Rheem Australia Pty Ltd Plugs for container closures

Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4335375A (en) * 1978-02-13 1982-06-15 Schaeffer Daniel D Container for an alarm transmitter adapted for insertion into a wall
US4473169A (en) * 1982-02-22 1984-09-25 Fitzgerald Fitz E Anti-theft plug and fastener
US11506291B2 (en) * 2018-11-27 2022-11-22 Hamilton Sundstrand Corporation Filter retaining plug and tool

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Publication number Publication date
CA976787A (en) 1975-10-28
GB1420588A (en) 1976-01-07
JPS50128050A (en) 1975-10-08
JPS545468B2 (en) 1979-03-16

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