CA2064371A1 - Manhole cover lock with spring biased locking bars - Google Patents
Manhole cover lock with spring biased locking barsInfo
- Publication number
- CA2064371A1 CA2064371A1 CA 2064371 CA2064371A CA2064371A1 CA 2064371 A1 CA2064371 A1 CA 2064371A1 CA 2064371 CA2064371 CA 2064371 CA 2064371 A CA2064371 A CA 2064371A CA 2064371 A1 CA2064371 A1 CA 2064371A1
- Authority
- CA
- Canada
- Prior art keywords
- shaft portion
- locking
- key
- manhole cover
- actuator
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Abandoned
Links
Landscapes
- Underground Structures, Protecting, Testing And Restoring Foundations (AREA)
Abstract
ABSTRACT OF THE DISCLOSURE
A locking manhole cover and key combination of the present invention is in the form of a manhole cover having a lock on its undersurface and a vent hole through the manhole cover. The lock comprises a plurality of locking bars spring biased to a locking position, a rotatable actuator accessible through the vent hole for moving the locking bars to an unlocking position with the key being fittable through the vent hole to operate the actuator. The key itself includes a first shaft portion turnable in the vent hole for rotating the actuator and pulling the locking bars to the unlocking position and a second shaft portion which when located in the vent hole prevents rotation of the actuator and holds the spring biased locking bars away from the locking position.
A locking manhole cover and key combination of the present invention is in the form of a manhole cover having a lock on its undersurface and a vent hole through the manhole cover. The lock comprises a plurality of locking bars spring biased to a locking position, a rotatable actuator accessible through the vent hole for moving the locking bars to an unlocking position with the key being fittable through the vent hole to operate the actuator. The key itself includes a first shaft portion turnable in the vent hole for rotating the actuator and pulling the locking bars to the unlocking position and a second shaft portion which when located in the vent hole prevents rotation of the actuator and holds the spring biased locking bars away from the locking position.
Description
FIELD OF THE INVENTION
The present invention relates to a vented lockable manhole cover where the lock on the cover does not affect the vent through the cover.
aACKGROUND OF THE_INVENTION
It is important that manhole covers be l~cked in position for a number of different reasons. For example, without being locked in position manhole covers can become dislodged simply by vibrations in the road surface to which they are fitted. Also, they are subject to vandalism and theft.
Conventional manhole covers include vent holes which allow unauthorized prying of the covers from the manhole frame. In some instances, young children after removing a manhole cover have climbed down into the sewer system below where they have been caught up in fast fiowing 20water and drowned. Also, the opening of the manhole covers allow unauthorized persons to have undesirable access to the sewer system.
There are presently in use several different 25manhole locking devices. One design is a J-bolt which goes through the existing manhole hole and bolts the frame to the cover. Another design is in the form of a water tight cover which again bolts the manhole to the frame.
In both of the arrangements described immediately above, the manhole cover is sealed and therefore does not allow the upward escape of gases past the manhole cover.
This can and has resulted in explosions within the sewer system beneath the manhole cover.
20~371 SJ-8240A - 2 - 4482~/0i0 In addition to being unsafe, the presently used techniques for locking a manhole cover in position are very labour intensive with respect to removing the covers for maintenance and/or inspections.
Other locking systems for manhole covers have been proposed in prior art patents. Such proposals are shown for example in United States Patents 3,921,494, 3,772.828, 4,577,478, 4,964,755, 4,9û2,165, and 2,363,567.
The problem with the structures described in the patents noted immediately above, is that they are not seif locking and therefore are subject to human error, i.e. even an authorized person opening the cover could well 15 inadvertently forget to lock the cover.
The cover plate in United States Patent 2,363,567 does show gravity operation of a lock bar on a manhole cover for moving the lock bar to a locking position. However 20 admitted in the patent, gravity is not sufficient to ensure proper locking of the bars and therefore a iocking key is additionally provided to move the bars to a locking position. The gravity operation of the bars requires that they not only move in and out but also up and down making 25 them relatively loose fitting and complicated in their operation.
SUMMARY OF THE PRESENT INVENTION
The present invention provides a very simple yet efficient locking manhole cover and key combination. The manhole cover includes a lock on its undersurface and a vent hole through the manhole cover which is not blocked by the lock. The lock itself comprises a plurality of locking bars 35 which are spring biased to a locking posltion, a rotatable .
, .
The present invention relates to a vented lockable manhole cover where the lock on the cover does not affect the vent through the cover.
aACKGROUND OF THE_INVENTION
It is important that manhole covers be l~cked in position for a number of different reasons. For example, without being locked in position manhole covers can become dislodged simply by vibrations in the road surface to which they are fitted. Also, they are subject to vandalism and theft.
Conventional manhole covers include vent holes which allow unauthorized prying of the covers from the manhole frame. In some instances, young children after removing a manhole cover have climbed down into the sewer system below where they have been caught up in fast fiowing 20water and drowned. Also, the opening of the manhole covers allow unauthorized persons to have undesirable access to the sewer system.
There are presently in use several different 25manhole locking devices. One design is a J-bolt which goes through the existing manhole hole and bolts the frame to the cover. Another design is in the form of a water tight cover which again bolts the manhole to the frame.
In both of the arrangements described immediately above, the manhole cover is sealed and therefore does not allow the upward escape of gases past the manhole cover.
This can and has resulted in explosions within the sewer system beneath the manhole cover.
20~371 SJ-8240A - 2 - 4482~/0i0 In addition to being unsafe, the presently used techniques for locking a manhole cover in position are very labour intensive with respect to removing the covers for maintenance and/or inspections.
Other locking systems for manhole covers have been proposed in prior art patents. Such proposals are shown for example in United States Patents 3,921,494, 3,772.828, 4,577,478, 4,964,755, 4,9û2,165, and 2,363,567.
The problem with the structures described in the patents noted immediately above, is that they are not seif locking and therefore are subject to human error, i.e. even an authorized person opening the cover could well 15 inadvertently forget to lock the cover.
The cover plate in United States Patent 2,363,567 does show gravity operation of a lock bar on a manhole cover for moving the lock bar to a locking position. However 20 admitted in the patent, gravity is not sufficient to ensure proper locking of the bars and therefore a iocking key is additionally provided to move the bars to a locking position. The gravity operation of the bars requires that they not only move in and out but also up and down making 25 them relatively loose fitting and complicated in their operation.
SUMMARY OF THE PRESENT INVENTION
The present invention provides a very simple yet efficient locking manhole cover and key combination. The manhole cover includes a lock on its undersurface and a vent hole through the manhole cover which is not blocked by the lock. The lock itself comprises a plurality of locking bars 35 which are spring biased to a locking posltion, a rotatable .
, .
2~64371 SJ-8240A - 3 - 44&28/Oi~i8 actuator accessible through the vent hole for moving the locking bars to an unlocking position with the key being fittable through the vent hole to operate the actuator.
''.
The key includes a first shaft portion which is turnable in the vent hole for rotating the actuator and pulling ~he locking bars to the unlocking position and a second shaft portion which when located in the vent hole, prevents rotation of the actuator and holds the spring 10 bias~ed locking bars away from the locking position.
In order to remove the key from the vent hoie, it must be released from the actuator with the locking bars then automatically springing back to their locking position.
BRIEF DESCRIPTION OF THE DRAWINGS
The above as well as other advantages and features of the present invention will be described in the detaiied ~description according to the preferred embodiments of the present invention in which;
Figure 1 is a top view of a manhole cover in accordance with the present invention;
Figure 2 is a sectiona~ view along the lines 2-~ of .
Figure 1;
Figure 3 is a plan view of the lock secured to the 25 underside of the manhole cover in Figure l;
Figure 4 is a side view of the lock of Figure 3;
Figure 4A is a side view of a somewhat modified lock according to a further preferred embodiment of the present invention;
30 Figure 5 is a side view of the operating key used for unlocking the lock of Figures 3 and 4;
Figure 6 is a'bottom plan view of the key shown in Figure 5.
DETAILED DESCRIPTION ACCORDING TO THE PREFERRED
EM80DIMENTS OF THE PRESENT INVENTION:
Figure 1 shows a manhole cover 1. This manhole .
, . . , ,~. - . ~
: : . ~ . . .
, 2~6~371 SJ-8240A - 4 - 4482~/OiOlB
cover when seen from above appears to have a standard construction including a combination vent and lift hoïe 3.
Figure 2 shows a sectionai view through the manhole 5 cover 1 as fitted to a manhoie support 5. This manhole support includes an inwardly extending lip or ledge 7jon which the manhole cover rests. iF 7 is additionaily useb to lock the manhole cover in position by a lock general'y indicated at 9 on the undersurface of the manhole cover.
Lock 9 which is better shown in Figures 3 and 4 of the drawings includes a mounting frame 19 having a plurality of attachment legs 21 which bolt directly to the cover.
Supported by the frame are a pair of movable locking bars 15 15, the movement of which is guided by frame 19.
The locking bars are pivotally secured to a rotatable disk actuator or control member 11. Actuator 11 is provided with a centrally located key opening i~.
20 Typically key opening 13 has a square shape which matches the shape of the lift or vent hole.
When the lock is mounted to the undersurface of the manhole cover key opening 13 is aligned directly beneath the 25 vent hole through the cover. This allows a key, generally indicated at 2g to be fitted down through the vent hole to operate actuator 11.
Also proviaed in the lock is a spring 2~ securea at 30 25 to one of the locking arms 15 and at 27 to the frame 19.
This spring normally biases both of the locking bars to a locking position as shown in Figure ~ of the drawings where the locking bars project outwardly of the frame beneath lip 7 in the manhole frame. The pulling of the spring on one of 35 the locking bars is translatea through the freely rotatable 20~371 SJ-8240A - 5 - 4482~/OlOlb actuator 11 to the other of the locking bars so that both locking bars normally assume the locking position as noteo above. With the locking bars in the Figure 2 position, the manhole cover cannot be lifted out of position from the manhole frame.
.
Figure 4A shows a lock slightly modified from the lock described above with respect tc Figures 3 and 4.
Consistent with the earlier embodiment, the lock shown in 10 Figure 4A includes an actuator plate lla which controls a pair of movable locking arms 15a. These arms are guided by frame l9a of the lock which additionally includes mounting legs 21a to mount the lock to the bottom side of the manhoie cover.
The lock shown in Figure 4A includes a coil spring 24 mounted to the frame and also secured to actuator plate lla to hold the actuator plate and the iocking arms in a locked position as earlier described. The actuator plate, 20 although not seen from above, has the identicai configuration and connections to the movable locking arms as that shown in figure 3. The ~method of rotating actuator plate lla is also the same as the method of rotating actuator plate 11 to be described later in detail.
Key 29 is used to rotate actuator 11 and move bars 15 to an unlocking position against the bias of spring 23.
This key has an elongated shaft comprising different shaft portions 31, 33, and 35. A rounded stop 37 is provided 30 above shaft portion 35 and an upper handle ~9 is used to rotate the key.
- As best seen in Figure 6 of the drawings the bottom shaft portion is of the key has a square configuration 35 matching that of key opening 13 in actuator 1l. Shaft . 2~6~371 SJ-8240A - 6 - 44~ b portion 31 also matches the shape of the lift hole allowing it to pass through the manhole cover to gain access to the actuator. The key is pushed sufficiently far down through the manhole cover so that the smaller diameter rounded 5 portion 33 of the key is located at the vent hole with shaft portion 31 in the key opening 13 of actuator 11. In this position the key can be rotated within the cover lift hole.
This in turn rot~tes the actuator to pull arms 15 to the unlocking position.
As a result of the spring bias on the arms, if the key was released in this position, the arms would simply spring back to their locking position. This would then necessitate holding the key in the unlocked position ~hiie 15 at the same time lifting on the manhole cover. Hawever, this problem is avoided by the provision of shaft portion 35 above shaft portion 33 on the key. As will be seen in Figure 6 of the drawings, shaft portion 35 again has a square configuration matching that of the vent hole. Shaft 20 portion 35 is located at about 90 relative to shaft portion 31. Therefore, after the key has been turned to rotate actuator 11 to the unlocking position, the key is pushed farther down to lock shaft portion 35 in the lift hole. This prevents rotation of both the key and the 25 actuator and holds arms 15 away from their normally assumed locking position.
Stop 37 prevents the key from being pushed down overly far into the manhole cover so that shaft portion 35 30 remains nested within the cover hole. Handle 39 is then used to pry the cover off of the manhole frame. Note that the cover does not have to be pulled directly upwardly but rather can be pried out of its position at an angle using the handle 39 on the key. Here it is to be noted that the 35 positioning of the vent hole to one side rather than in the .
20~371 SJ-8240A - 7 - 4482~/OlOiB
middle of the cover, provides assistance in prying the cover from the frame. After the lock has been released one simply pushes downwardly on the key which, as noted above, will not go farther into the hole because of stop 37. This causes the one side of the cover to effectively fulcrum downwardly so that the other side of the cover pivots upwardly. One can now grip the up side of the cover to pull it from the frame.
In order to get the key back out of the manhoie cover~ it must be lifted to release shaft portion 35 from the left hole and then returned to a position in which lower shaft portion 31 aligns with the lift hole. In this same position, the actuator 11 is allowed to return to its 15 starting position where the lock bars 15 have once again resumed their locking positions. Therefore, in order to get the key out of the manhole cover, the lock bars must be in the locked position. They wili continue to hold this locked position because of the spring bias and can only be pulled 20 away from the locked position by the use of the operating key.
In the Figures 3 and 4 embodiment lock, there is, aQ noted above, a connection of the spring 23 between point 25 25 on arm 15 and point 27 on the frame of the lock. In the embodiment shown in Figure 4A, the lower end of spring 24 is connected to frame l9a while the upper end of the spring is connected to the actuator plate. In a normal or relaxed condition, spring 24 holas actuator plate lla in the locking 30 position. As the actuator plate is rotated to the unlocking position, the spring is coiled because the one end of the spring is free to rotate with the actuator plate while the other end of the spring is secured to the frame. Tne spring therefore wants to return the actuator plate to the locking 35 position but is prevented from doing so when shaft portion 35 of key 29 is locked ln the vent hole as described above.
.
2~371 SJ-8240A - 8 - 448'~B/OiOiB
The coil spring arrangement shown in Figure 4A
provides a very strong bias on the actuator plate without requiring an overly large spring. Furthermore, the connection of the coil spring is achieved in a very simple ~. .
yet efficient manner. The tight windings on coil spring 24 are such that it provides a very substantial resistance to even a sl,ight unwinding of the spring and therefore the spring has an essentialiy ùnlimited lifespan.
A further feature to be noted through the use of coil spring 24 is that even though it is located directly in line beneath key opening 13a in actuator plate lla, the spring has a hollow core and therefore does not block insertion of the key down ,through the key opening.
Although various preferred embodiments of the invention have been described in detail, it will be appreciated that variations can be made without departing from the spirit of the invention or the scope of the 20 appended claims.
. . .
''.
The key includes a first shaft portion which is turnable in the vent hole for rotating the actuator and pulling ~he locking bars to the unlocking position and a second shaft portion which when located in the vent hole, prevents rotation of the actuator and holds the spring 10 bias~ed locking bars away from the locking position.
In order to remove the key from the vent hoie, it must be released from the actuator with the locking bars then automatically springing back to their locking position.
BRIEF DESCRIPTION OF THE DRAWINGS
The above as well as other advantages and features of the present invention will be described in the detaiied ~description according to the preferred embodiments of the present invention in which;
Figure 1 is a top view of a manhole cover in accordance with the present invention;
Figure 2 is a sectiona~ view along the lines 2-~ of .
Figure 1;
Figure 3 is a plan view of the lock secured to the 25 underside of the manhole cover in Figure l;
Figure 4 is a side view of the lock of Figure 3;
Figure 4A is a side view of a somewhat modified lock according to a further preferred embodiment of the present invention;
30 Figure 5 is a side view of the operating key used for unlocking the lock of Figures 3 and 4;
Figure 6 is a'bottom plan view of the key shown in Figure 5.
DETAILED DESCRIPTION ACCORDING TO THE PREFERRED
EM80DIMENTS OF THE PRESENT INVENTION:
Figure 1 shows a manhole cover 1. This manhole .
, . . , ,~. - . ~
: : . ~ . . .
, 2~6~371 SJ-8240A - 4 - 4482~/OiOlB
cover when seen from above appears to have a standard construction including a combination vent and lift hoïe 3.
Figure 2 shows a sectionai view through the manhole 5 cover 1 as fitted to a manhoie support 5. This manhole support includes an inwardly extending lip or ledge 7jon which the manhole cover rests. iF 7 is additionaily useb to lock the manhole cover in position by a lock general'y indicated at 9 on the undersurface of the manhole cover.
Lock 9 which is better shown in Figures 3 and 4 of the drawings includes a mounting frame 19 having a plurality of attachment legs 21 which bolt directly to the cover.
Supported by the frame are a pair of movable locking bars 15 15, the movement of which is guided by frame 19.
The locking bars are pivotally secured to a rotatable disk actuator or control member 11. Actuator 11 is provided with a centrally located key opening i~.
20 Typically key opening 13 has a square shape which matches the shape of the lift or vent hole.
When the lock is mounted to the undersurface of the manhole cover key opening 13 is aligned directly beneath the 25 vent hole through the cover. This allows a key, generally indicated at 2g to be fitted down through the vent hole to operate actuator 11.
Also proviaed in the lock is a spring 2~ securea at 30 25 to one of the locking arms 15 and at 27 to the frame 19.
This spring normally biases both of the locking bars to a locking position as shown in Figure ~ of the drawings where the locking bars project outwardly of the frame beneath lip 7 in the manhole frame. The pulling of the spring on one of 35 the locking bars is translatea through the freely rotatable 20~371 SJ-8240A - 5 - 4482~/OlOlb actuator 11 to the other of the locking bars so that both locking bars normally assume the locking position as noteo above. With the locking bars in the Figure 2 position, the manhole cover cannot be lifted out of position from the manhole frame.
.
Figure 4A shows a lock slightly modified from the lock described above with respect tc Figures 3 and 4.
Consistent with the earlier embodiment, the lock shown in 10 Figure 4A includes an actuator plate lla which controls a pair of movable locking arms 15a. These arms are guided by frame l9a of the lock which additionally includes mounting legs 21a to mount the lock to the bottom side of the manhoie cover.
The lock shown in Figure 4A includes a coil spring 24 mounted to the frame and also secured to actuator plate lla to hold the actuator plate and the iocking arms in a locked position as earlier described. The actuator plate, 20 although not seen from above, has the identicai configuration and connections to the movable locking arms as that shown in figure 3. The ~method of rotating actuator plate lla is also the same as the method of rotating actuator plate 11 to be described later in detail.
Key 29 is used to rotate actuator 11 and move bars 15 to an unlocking position against the bias of spring 23.
This key has an elongated shaft comprising different shaft portions 31, 33, and 35. A rounded stop 37 is provided 30 above shaft portion 35 and an upper handle ~9 is used to rotate the key.
- As best seen in Figure 6 of the drawings the bottom shaft portion is of the key has a square configuration 35 matching that of key opening 13 in actuator 1l. Shaft . 2~6~371 SJ-8240A - 6 - 44~ b portion 31 also matches the shape of the lift hole allowing it to pass through the manhole cover to gain access to the actuator. The key is pushed sufficiently far down through the manhole cover so that the smaller diameter rounded 5 portion 33 of the key is located at the vent hole with shaft portion 31 in the key opening 13 of actuator 11. In this position the key can be rotated within the cover lift hole.
This in turn rot~tes the actuator to pull arms 15 to the unlocking position.
As a result of the spring bias on the arms, if the key was released in this position, the arms would simply spring back to their locking position. This would then necessitate holding the key in the unlocked position ~hiie 15 at the same time lifting on the manhole cover. Hawever, this problem is avoided by the provision of shaft portion 35 above shaft portion 33 on the key. As will be seen in Figure 6 of the drawings, shaft portion 35 again has a square configuration matching that of the vent hole. Shaft 20 portion 35 is located at about 90 relative to shaft portion 31. Therefore, after the key has been turned to rotate actuator 11 to the unlocking position, the key is pushed farther down to lock shaft portion 35 in the lift hole. This prevents rotation of both the key and the 25 actuator and holds arms 15 away from their normally assumed locking position.
Stop 37 prevents the key from being pushed down overly far into the manhole cover so that shaft portion 35 30 remains nested within the cover hole. Handle 39 is then used to pry the cover off of the manhole frame. Note that the cover does not have to be pulled directly upwardly but rather can be pried out of its position at an angle using the handle 39 on the key. Here it is to be noted that the 35 positioning of the vent hole to one side rather than in the .
20~371 SJ-8240A - 7 - 4482~/OlOiB
middle of the cover, provides assistance in prying the cover from the frame. After the lock has been released one simply pushes downwardly on the key which, as noted above, will not go farther into the hole because of stop 37. This causes the one side of the cover to effectively fulcrum downwardly so that the other side of the cover pivots upwardly. One can now grip the up side of the cover to pull it from the frame.
In order to get the key back out of the manhoie cover~ it must be lifted to release shaft portion 35 from the left hole and then returned to a position in which lower shaft portion 31 aligns with the lift hole. In this same position, the actuator 11 is allowed to return to its 15 starting position where the lock bars 15 have once again resumed their locking positions. Therefore, in order to get the key out of the manhole cover, the lock bars must be in the locked position. They wili continue to hold this locked position because of the spring bias and can only be pulled 20 away from the locked position by the use of the operating key.
In the Figures 3 and 4 embodiment lock, there is, aQ noted above, a connection of the spring 23 between point 25 25 on arm 15 and point 27 on the frame of the lock. In the embodiment shown in Figure 4A, the lower end of spring 24 is connected to frame l9a while the upper end of the spring is connected to the actuator plate. In a normal or relaxed condition, spring 24 holas actuator plate lla in the locking 30 position. As the actuator plate is rotated to the unlocking position, the spring is coiled because the one end of the spring is free to rotate with the actuator plate while the other end of the spring is secured to the frame. Tne spring therefore wants to return the actuator plate to the locking 35 position but is prevented from doing so when shaft portion 35 of key 29 is locked ln the vent hole as described above.
.
2~371 SJ-8240A - 8 - 448'~B/OiOiB
The coil spring arrangement shown in Figure 4A
provides a very strong bias on the actuator plate without requiring an overly large spring. Furthermore, the connection of the coil spring is achieved in a very simple ~. .
yet efficient manner. The tight windings on coil spring 24 are such that it provides a very substantial resistance to even a sl,ight unwinding of the spring and therefore the spring has an essentialiy ùnlimited lifespan.
A further feature to be noted through the use of coil spring 24 is that even though it is located directly in line beneath key opening 13a in actuator plate lla, the spring has a hollow core and therefore does not block insertion of the key down ,through the key opening.
Although various preferred embodiments of the invention have been described in detail, it will be appreciated that variations can be made without departing from the spirit of the invention or the scope of the 20 appended claims.
. . .
Claims
PROPERTY OR PRIVILEGE IS CLAIMED ARE DEFINED AS FOLLOWS:
l. A locking manhole cover and key combination said manhole cover having a lock lo the underside thereof and a vent hole through said manhole cover, said lock comprising a plurality of locking bars spring biased to a locking position, a rotatable actuator accessible through said vent hole for moving said locking bars to an unlocking position with said key being fitted through said vent hole to operate said actuator said key including a first shaftportion turnable in said vent hole for rotating said actuator and pulling said locking bars to the unlocking position and a second shaft portion which locks against turning in said vent hole thereby preventing rotation of said actuator and holding said spring biased locking bars away from said locking position.
2. A locking manhole cover and key combination is claimed in claim 1, wherein said actuator includes a stop to prevent downward movement of said key past said stop.
3. A locking manhole cover and key combination is claimed in claim 1, wherein said actuator includes a key opening and wherein said key comprises a lower shaft portion with an angled face, a smaller diameter shaft portion above said lower shaft portion and an upper shaft portion with an angled face above said smaller diameter shaft portion, the angled face on said lower shaft portion being rotational off-set from the angled face on said upper shaft portion.
4. A locking manhole cover and key combination is claimed in
claim 1, wherein said lower shaft portion is rectangular, said smaller diameter shaft portion is rounded, and said upper diameter shaft portion is rectangular and turned at 90 degrees relative to said lower shaft portion.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CA 2064371 CA2064371A1 (en) | 1992-03-27 | 1992-03-27 | Manhole cover lock with spring biased locking bars |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CA 2064371 CA2064371A1 (en) | 1992-03-27 | 1992-03-27 | Manhole cover lock with spring biased locking bars |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA2064371A1 true CA2064371A1 (en) | 1993-09-28 |
Family
ID=4149512
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA 2064371 Abandoned CA2064371A1 (en) | 1992-03-27 | 1992-03-27 | Manhole cover lock with spring biased locking bars |
Country Status (1)
| Country | Link |
|---|---|
| CA (1) | CA2064371A1 (en) |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| GB2500979A (en) * | 2012-02-24 | 2013-10-09 | Anthony Molloy | Lock assembly with key retaining aperture |
-
1992
- 1992-03-27 CA CA 2064371 patent/CA2064371A1/en not_active Abandoned
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| GB2500979A (en) * | 2012-02-24 | 2013-10-09 | Anthony Molloy | Lock assembly with key retaining aperture |
| GB2500979B (en) * | 2012-02-24 | 2018-02-07 | Northstone (Ni) Ltd | Lock assembly |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| US5082392A (en) | Manhole cover lock with spring biased locking bars | |
| US4964755A (en) | Manhole cover lock apparatus | |
| US2594012A (en) | Meter box and cover therefor | |
| US4884424A (en) | Mortise cylinder lock guard | |
| US4502167A (en) | Apparatus for securing a toilet bowl lid closed | |
| US4142329A (en) | Catch basin grate and receiving frame locking assembly | |
| US4037700A (en) | Coin vault | |
| US4240278A (en) | Gate locking device | |
| EP0227447A2 (en) | Parking post | |
| CA2064371A1 (en) | Manhole cover lock with spring biased locking bars | |
| JPS5818505B2 (en) | Tobirajyou | |
| GB2323617A (en) | Telescopic Post | |
| US5167093A (en) | Parking barrier | |
| JP2962408B2 (en) | Mounting device for safety guard for manhole | |
| US4683731A (en) | Latching device | |
| US20030090284A1 (en) | Device and method for opening a door | |
| GB2262119A (en) | Lockable access cover | |
| JP3975238B2 (en) | Locking device for lid of underground structure | |
| JPS5812921Y2 (en) | iron lid locking device | |
| JP3107373B2 (en) | Falling prevention ladders and underframes for underground structures with falling prevention ladders | |
| JP2963884B2 (en) | Mounting device for safety guard for manhole | |
| KR200212754Y1 (en) | Inner cover device with locking means for use in manhole | |
| JPH072905Y2 (en) | Locking device for grating lid | |
| JPH069074Y2 (en) | Locking device for closing the operation hole for opening and closing the manhole cover | |
| JP3758798B2 (en) | Locking structure for lids for underground structures |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| EEER | Examination request | ||
| FZDE | Dead |