High security manhole insert cover

[0002] None

[0003] 1. Field of Invention

[0004] The security manhole insert cover relates to a locking manhole insert to prevent ingress or egress to a manhole from above or below the manhole to prevent access to underground utilities, tunnels and underneath buildings and metropolitan areas to eliminate security intrusions and terrorist attacks by underground access, which would otherwise go undetected if access to the underground utility passages were not secured. The manhole insert cover has a cylindrical locking insert barring access to the engaging and disengaging mechanism required to remove the manhole insert cover and an integrated lower cover to prevent access to the engaging and disengaging mechanism from below, the insert cover adapted to fit within a manhole without required modification of the manhole and without detection of the insert cover having been installed from above ground levels.

[0005] 2. Description of Prior Art

[0006] The following United States patents were discovered and are disclosed within this application for utility patent. All relate to locking hole covers.

[0007] A first series of prior art patents involve simple manhole inserts without disclosed locking mechanisms. Those two patents, U.S. Pat. No. 6,393,771 to Stetson and U.S. Pat. No. 4,919,564 to Neathery, disclose manhole inserts, Stetson merely providing a cover and ring which insert into a manhole and allow the insert to be filled with a road surfacing material to blend in with its surrounding roadway, the insert including at least two holes to allow water to pass through the insert. Neatherly is a sealed insert to prevent water intrusion into the manhole, with a pressure relief and vent access through the insert cover.

[0008] A second set of patents disclose manhole covers with locking devices, but not secure locking devices. Those patents include U.S. Pat. No. 911,256 to McWane, which discloses a meter box cover with a hinged lid that has a rotating closure means in the hinged lid, U.S. Pat. No. 1,001,041 to Jones, which discloses a rotating lock arm attached to a manhole cover which requires a key insertion to turn the rotating locking arm, and U.S. Pat. No. 1,458,391 to Burton, which has a turning handle that when lifted, provides a rotating force to rotate a cam to disengage two arms for removal of the manhole cover. Two more recent US patents, including U.S. Pat. No. 5,082,392 to Marchese and U.S. Pat. No. 5,987,824 to Fuller, involve more detailed mechanisms to engage and disengage their manhole covers to a hole or manhole, with Fuller having a threaded conical component that travels upward when rotated, forcing several locking wedges outward, anchoring the manhole cover to the hole by outward force, while Marchese involves spring loaded locking arms that require a rotating force to retract the spring loaded arms for removal of the manhole cover, the rotating force provided by a shaped key inserted into a respectively shaped keyhole.

[0009] A third set of US patents involve secure lock mechanisms to which padlocks are supplied as the securing component. These US Patents include U.S. Pat. No. 5,328,291 to Wisniewski, U.S. Pat. No. 5,827,007 to Barton and U.S. Pat. No. 6,488,440 to Hill. Hill defines a manhole cover having a molly-type locking arm that is engaged and disengaged by several turns of the rotating shaft, to which includes an upper eyelet through which a chain is padlocked to prevent unauthorized turning of the shaft. Barton includes a locking bar bolted to a manhole insert by a nut through which a strand is pulled and padlocked to prevent removal of the nut from an upward extending stud. Wisniewski is a manhole insert having a rotating cam mechanism having a hasp that is padlocked to a stationary hasp to prevent disengagement of the extending locking arms. All three of these may be removed by the use of bolt cutters, which takes little time and makes little noise during use to bypass the securing.

[0010] None of the above devices prevent access from and under side and none of the above devices include a similar locking means, nor do they furnish the secure locking means as disclosed in the current invention. While they may each bear some semblance to the current invention, they do not, either singularly or in combination, disclose the features of the current invention.

[0011] More so now than at any time in the past, public awareness of domestic threats of security are presented, with focus on areas that would allow operations out of the ordinary perception. As this awareness increases, so does the potential for security breaches in areas that are not conspicuous, primarily those underground in urban or high security areas. Access to underground utilities, tunnel systems that travel beneath buildings and underground mass transit systems is often had through manholes that are either in the streets or sidewalks, these manholes existing for decades. In lieu of replacing the existing manhole systems with other costly modified access means, a security insert for manholes which offers virtual impenetrable ingress and egress is provided in the security manhole insert cover for manholes, preventing the removal of the insert cover from either the top or bottom without required alteration of the manholes.

[0012] The primary objective of the invention is to provide a security manhole seal to prevent access to underground tunnels and utilities by the application of an insert which does not require alteration of the manhole or its cover.

[0013] A secondary objective of the invention is to provide the security manhole insert cover with a completely sealed cam lock which cannot be accessed from the top or the bottom without having a key operating a cylindrical lock that denies access to the cam lock and cannot be picked , pried or cut with a mechanical tool.

[0014] A third objective of the invention is to fabricate the insert cover out of a material which can not be damaged or removed without complex intervention, i.e., plasma cutting tools and explosives, which would alert the general public to the use of such bypass means to access the manhole before such access was had. In furtherance of this objective, the entire insert cover is made of stainless steel.

[0015] The following drawings are submitted with this utility patent application.

[0016] FIG. 1 is a perspective view of the insert cover in a manhole.

[0017] FIG. 2 is top view of the insert cover.

[0018] FIG. 3 is an underside view of the insert cover.

[0019] FIG. 4 is an underside inner view of a first embodiment of the insert cover with the lower plate removed.

[0020] FIG. 5 is a side cross section of the insert cover using a first embodiment of the rotatable locking means.

[0021] FIG. 6 is a side view of the insert cover.

[0022] FIG. 7 is a top view of the spiral cam wheel of the first embodiment of the insert cover.

[0023] FIG. 8 is a side view of the locking arm which engages the spiral cam wheel.

[0024] FIG. 9 is a top view of the flanged cam wheel of the second embodiment of the insert cover.

[0025] FIG. 10 is a side view of the locking arm which engages the flanged cam wheel.

[0026] FIG. 11 is a side cross section of the insert cover with the second embodiment of the rotatable locking means.

[0027] FIG. 12 is a view of the slot key in the central slot.

[0028] FIG. 13 is an underside inner view of the second embodiment of the insert cover with the lower plate removed.

[0029] A high security manhole insert, shown in FIGS. 1-13 of the drawings, which requires no modification of an existing manhole 100, a manhole entrance 102 or a manhole cover 104, the manhole insert placed within the manhole entrance 102 to provide a high security blockade to ingress or egress to the manhole 100 from above and below, the high security manhole insert comprising essentially a circular perimeter rim 20 having an upper flange 22 upon which the manhole cover 104 is replaced after installation to the manhole entrance 102, a lower plate 30 connected to the perimeter rim 20, an upper plate 40 also attached to the perimeter rim 20 above the lower plate 30, with the perimeter rim 20, the upper plate 40 and the lower plate 30 defining an inner cavity 50 within which is placed a rotatable locking means 70 having a central slot 72, receiving a slot key 74, a plurality of extendable locking arms 80 extending through the perimeter rim 20 extended by the rotation of the rotatable locking means 70, the lower plate 30 preventing any access to the rotatable locking means 70 from below and the upper plate 40 limiting the slot key 74 access to the central slot 72 of the rotatable locking means 70 through a recessed cylindrical access hole 42 having a cylindrical lock housing 44 in said upper plate 40, the cylindrical lock housing 44 adapted to accept a cylindrical lock 60 having a vertical locking member 62, the cylindrical lock 62 requiring a key.

[0030] More specifically and most preferably, the entire manhole insert is made of stainless steel or other high strength metal product requiring use of at least a plasma torch to penetrate the manhole insert. The circular perimeter rim 20 is adapted to fit securely within a manhole entrance 102, shown in FIG. 1 of the drawings, the circular perimeter rim 20 having a plurality of locking arm holes 24 to allow the locking arms 80 to traverse the perimeter rim 20. The upper flange 22 is adapted to fit within the manhole entrance 102 underneath the manhole cover 104, resting above the manhole entrance 102, while positioning each locking arm hole 24 below the manhole entrance 102, locking the manhole insert to the manhole entrance 102.

[0031] The lower plate 30 is preferably slightly concave, which allows for water intruding into the inner cavity 50 to collect and pool in an outer portion 32 of the lower plate 30, where at least one drain hole 34 would be provided. The upper plate 40 may be flat or slightly concave and includes the recessed cylindrical access hole 42, shown in FIGS. 1, 2 and 5, which is aligned with the central slot 72 in the rotatable locking means 70 to lock and unlock the manhole insert for attachment and removal. The attachment of the upper plate 40 to the perimeter rim 20 is most preferably by welding, but the attachment of the lower plate 30 to the perimeter rim 20 may be by rivet, welding or bolting, as shown in FIG. 3.

[0032] The rotatable locking means 70 is shown as two embodiments in the drawings. In the first embodiment, shown in FIGS. 4, 5, 7 and 8, the rotatable locking means 70 is a spiral cam 90ahaving a plurality of spiral slots 92 machined in the spiral cam 90awith a central hole 94a. This spiral cam 90ais attached to the lower plate 30 by a cam support pedestal 76, FIG. 5, having a central shaft 78 extending upward from the lower plate 30 engaging the central hole 94a. Attached above the central hole 94a, further attached to the spiral cam 90ais the central slot 72, also FIG. 5. The spiral cam 90ais thus rotated by turning the inserted slot key 74, FIG. 12 within the central slot 72 rotating the spiral cam 90aclockwise and counter clockwise. A plurality of extendable first locking arms 80aconnect within the spiral slots 92 by cam bearings 84apositioned on a first end 82aof the first locking arms 80a, FIG. 8, which allow the first end 82aof the first locking arms 80ato move freely within the spiral slots 92. A second end 86aof the first locking arms 80aextends through the locking arm holes 24 of the perimeter rim 20, FIG. 6. As the spiral cam 80ais turned, the first locking arms 80aare either urged inward or outward from the perimeter rim 20 to lock and unlock the manhole insert from the manhole entrance 102. A slight taper is preferred on the second end 86aof the first locking arms 80a.

[0033] Positioned above the central slot 72 and central hole 94aof the spiral cam 90ais a cylindrical lock housing 44 below the recessed cylindrical access hole 42 in the upper plate 40, FIG. 5. This cylindrical lock housing 44 is adapted to receive the cylindrical lock 60 and the vertical locking member 62, FIGS. 5 and 11. The cylindrical lock housing 44 allows for the insertion of the cylindrical lock 60 and with a slight rotation, the cylindrical lock housing 44 having a locking hole 46 through which the vertical locking member 62 of the cylindrical lock 60 may extend, locks the cylindrical lock 60 within the cylindrical lock housing 44, completely blocking all access to the central slot 72 and the spiral cam 90abelow. This cylindrical lock 60 cannot be cut by bolt cutters and should be comprised of a strong metal, preferably a high carbon steel. The cylindrical lock 60 includes an upper surface 66 which should lie flush with an upper surface 48 of the upper plate 40 when said cylindrical lock 60 is locked within cylindrical lock housing 44. Most suited for application as the cylindrical lock 60 is the AMERICAN LOCK® 2500 Series Padlock.

[0034] In a second embodiment of the manhole insert, shown in FIGS. 9-13, the rotatable locking means 70 is provided by a flanged cam 90b, FIG. 9, having a plurality of extending flanges 91 incorporated into an outer perimeter 93 of the flanged cam 90b, said flanged cam 90bhaving a central hole 94b. This flanged cam 90bis also attached to the lower plate 30 by a cam support pedestal 76 having a central shaft 78 extending upward from the lower plate 30 engaging the central hole 94b, FIG. 11. Attached above the central hole 94b, further attached to the flanged cam 90bis the central slot 72. The flanged cam 90bis thus rotated by turning the inserted slot key 74 within the central slot 72 rotating the flanged cam 90bclockwise and counter clockwise, FIG. 12.

[0035] In this second embodiment, a plurality of second locking arms 80bare not directly connected to the flanged cam 90b, but each second locking arm 80bslideably engages a support bracket 81 attached to the perimeter rim 20, aligned with the locking arm holes 24, FIGS. 11 and 13. Each second locking arm 80b, FIG. 10, includes a first end 82bhaving a cam buttress 83 which abuts the outer perimeter 93 of the flanged cam 90bas it is turned, this cam buttress 83 including a cam bearing 84b, an upper stabilizer plate 85 and lower stabilizer plate 87, the upper and lower stabilizer plates 85, 87 maintaining the cam buttress 83 against the flanged cam 90bwhile the cam bearing 84brides smoothly against the outer perimeter 93 of the flanged cam 90b. Also included on each second locking arm 80bis a spring 88, FIGS. 10 and 13, retained on the second locking arm 80bbetween a pin 89 and each support bracket 81, wherein the spring 88 urges the second locking arm 80bagainst the flanged cam 90b. A second end 86bof the second locking arm 80bextends through each support bracket 81 and through the locking arm holes 24 of the perimeter rim 20, also FIG. 6. As the flanged cam 90bis rotated, the second locking arms 80bare urged outward or retract inward from the perimeter rim 20 to lock and unlock the manhole insert from the manhole entrance 102. A slight taper is preferred on the second end 86bof the second locking arms 80b.

[0036] Also positioned above the central slot 72 and central hole 94bof the flanged cam 90bis the same cylindrical lock housing 44 below the recessed cylindrical access hole 42 in the upper plate 40 as was provided with the first embodiment including the spiral cam 90a. This cylindrical lock housing 44 also is adapted to receive the cylindrical lock 60 and the vertical locking member 62. The cylindrical lock housing 44 allows for the insertion of the cylindrical lock 60 and a slight rotation, the cylindrical lock housing 44 having a locking hole 46 through which the vertical locking member 62 of the cylindrical lock 60 may extend to lock the cylindrical lock 60 within the cylindrical lock housing 44, completely blocking all access to the central slot 72 and the flanged cam 90bbelow. This cylindrical lock 60 also cannot be cut by bolt cutters and should be comprised of a strong metal, preferably a high carbon steel. The cylindrical lock 60 includes the upper surface 66 which should lie flush with the upper surface 48 of the upper plate 40 when said cylindrical lock 60 is locked within the cylindrical lock housing 44. Again, most suited for application as the cylindrical lock 60 is the AMERICAN LOCK® 2500 Series Padlock.

[0037] While the invention has been particularly shown and described with reference to a preferred embodiment thereof, it will be understood by those skilled in the art that changes in form and detail may be made therein without departing from the spirit and scope of the invention.