NZ247626A - Manhole or pit cover secured by spring latch arms retained under compression - Google Patents

Description

Complete Specification Filed: Class: tmazahur • • dWW&9//P....

Publication Date: ...?J??j. P.O. Journal, No: ., I N.2. PATEnnrnpcyy Patents Form No. 5 U MAY 1993 NEW ZEALAND PATENTS ACT 1953 COMPLETE SPECIFICATION A SYSTEM FOR SECURING MANHOLE AND PIT COVERS I, GRAHAME GEORGE KERMONDE, an Australian citizen of 102 Henkel Street, Brunswick, Victoria 3056, Australia hereby declare the invention, for which I pray that a patent may be granted to me, and the method by which it is to be performed, to be particularly described in and by the following statements ■ :r 2 A SYSTEM FOR SECURING MANHOLE AND PIT COVERS The invention relates to a system for securing manhole and pit covers; grates, drain security covers and in particular, telecommunication covers and pit lids.

It is generally required by the Water Board, Telecom etc. to prevent the public from gaining access to the pipes, drains (either stormwater or sewage) or telecommunication equipment, for a number of reasons including the public safety policy aspect as well as in the case of telecommunication equipment, the possible damage which could occur to the expensive and important equipment 10 stored under the manhole and pit covers.

On the issue of safety, statutory and Government bodies such as Telecom and the Water Board can arguably be held to be negligent if the covers can be removed by children and adolescent vandals and some harm comes to the children or vandals. Thus, essentially, such organisations wish to avoid any 15 such incidents and must take steps to prevent them happening.

In respect of possible damage to telecommunication equipment with the advent of communication equipment becoming more compact, the area under manhole covers can house expensive and important equipment. As well as telecommunication cables, which any damage thereto can amount to millions of 20 dollars in lost revenue and disruption to businesses using the same.

Some attempts have been made in the prior art to address the problems of preventing persons from obtaining entry into manholes or pits and thus minimise the damage that can occur. However, previous attempts have not been particularly effective in preventing vandals or unauthorised persons from 25 entering the manhole or pit. The prior attempts included additional locking arrangements affixed to the manhole/pit cover, however these were generally not successful because the arrangements were apparent to the potential intruders and thus the way to enter the pit was obvious.

Whilst attempts have been made to address the problem of disguising the 30 locking mechanisms and thus also the route to entry, the prior art attempts have generally been complex in structure. Because of the complexity of the prior art structures, they were unreliable and the cost (in the form of labour and expense) of producing the apparatus and maintaining the same in working order has been, to date, quite significant.

An example of the prior arts attempt to address the problem of security in relation to manhole covers is disclosed in US Patent No. 5,082,392. This patent 5 discloses a locking manhole cover and key combination and in particular, discloses the use of rigid arms which are mounted upon a rotatable actuator. The arms have attached thereon a spring mechanism to ensure that the arms are retained under tension and more importantly, according to the inventors, to ensure that the arms are retained in the "locked position". The problems with this 10 mechanism is that because of the complexity of the arrangement and in particular, the use of a significant number of interrelated parts, the mechanism is expensive, difficult and laborious to install and maintain in working order. Additionally, the mechanism is more prone to tampering because of its tendency to be unreliable.

Further to the issue of safety, workers for the statutory and Government bodies continuously, on their rounds, need to gain access to the manholes and pits. However, it has become a recent problem, with the increased risk of contracting AIDS, of syringes being placed in the access holes of manhole or pit covers. Workers have been stabbed by an unexpected syringe and thus there is 20 a great need to effectively close-off access holes in manhole and pit covers as well as secure the covers themselves.

The present invention addresses some of the problems of the prior art and in particular, provides a system which is simple in design and effective in preventing the unwanted entry into manholes and pits.

According to a first aspect, the present invention provides a security system for a cover for a manhole or a pit comprising a latch actioning means, and at least two spring latch arms operatively connected to said latch actioning means, wherein said spring latch arms are retained under compression when the cover is in a closed position of use overlying said manhole or pit. 30 The latch actioning means can be actioned by a conventional manhole or pit cover key.

Preferably the spring latch arms have at least one curve, and more preferably an S-portion in their length. The spring latch arms are preferably located on the, preferably rotatable, latch actioning means such that in the locked position and, in situ, the arms are "over-centre" and thus cannot be 5 disengaged by simply pushing on the spring latch arms.

The latch arms may cooperate with the wall of the pit or manhole or the ground.

The security system can be formed into the manhole cover or pit cover during themanufacture thereof or as a retrofit.

The security system may be made of metal or plastic.

In accordance with a further aspect, the present invention provides a manhole or pit cover comprising a cover member including a lifting hole located therein, a latch actioning means located beneath said lifting hole and accessible through said lifting hole, at least two spring latch arms operatively connected to 15 said latch actioning means at an inner end with each said spring latch arm having an outer end engagable, in use, with abutment means surrounding said manhole or pit cover whereby a compressive force is applied to said latch actioning means and said abutment means by each said spring latch arm.

According to a still further aspect, the present invention provides a 20 manhole or pit cover comprising a cover member including a lifting hole located therein, a rotatable latch actioning means located beneath said lifting hole and accessible through said lifting hole, at least two spring latch arms operatively connected to said lifting hole, at least two spring latch arms operatively connected to said latch actioning means at an inner end with each said spring 25 latch arm having an outer end engagable, in use, with abutment means surrounding said manhole or pit cover, whereby a compressive force is applied to said latch actioning means and said abutment means by each said spring latch arm, the inner ends of said spring latch arms being arranged such that an externally applied inward force on said spring latch arms urges rotation of said 30 latch actioning means in a direction opposite to that necessary to release said outer ends from engagement with said abutment means. 247626 4a In the foregoing and throughout this specification reference is made to manhole and pit covers, however, it will be appreciated that this terminology includes all comparable applications including grates, drain security covers, 5 telecommunication covers and the like.

Preferably the present invention may further include a device adapted to obstruct removal of a cover from a manhole or pit, said device comprising a first resilient means adapted to fit into a lifting hole or recess in the manhole or pit cover and a second means which cooperates with said first resilient means and 10 is adapted to expand said first resilient means such that when said first resilient means is inserted into said lifting hole or recess and second means is actively positioned with said first resilient means, said first resilient means forms an interference pit in said lifting hole a recess thereby obstructing removal of said first resilient means from said lifting hole or recess.

Preferably, said second means fits within said first resilient means. The device is preferably one single component; however, the first and second device is preferably one single component; however, the first and second means may be separate components.

The first resilient means may act as a housing for said second means. 20 The device of the invention may be made of metal or plastic. In the case of the first means this may be made of any resilient material. The second means can be made of any solid material.

The device of the present invention can be used alone or in combination with other security means. The device of the present invention is preferably 25 actioned manually or by a key and preferably unlocked by a key.

The various aspects of the invention can be used in combination with each other, even though each of the aspects can be used alone.

Advantageously, the present invention provides an effective, yet simple system of preventing access to a manhole or pit without the shortcomings of the 30 prior art.

The invention may be further understood from the following discussion of some preferred embodiments of the invention.

Figure 1a - a conventional cast iron manhole cover currently in use.

Figure 1 b - another conventional cement pit cover currently in use.

Figure 2 - illustrates one aspect of the invention.

Figure 3a - illustrates a detailed aspect of the invention viewing from underneath the cover in the unlocked position.

Figure 3b - illustrates a detailed aspect of the invention viewing from underneath the cover in the locked position.

Figure 4a - illustrates an embodiment of the locking mechanism aspect of the invention from a bottom view.

Figure 4b - illustrates an embodiment of the locking mechanism aspect of the invention from the top view.

Figure 5 illustrates another aspect of the invention when made from 15 plastic.

Figure 6a - illustrates a sample of the prior art.

Figure 6b - illustrates one embodiment of one aspect of the invention.

Figure 6c - illustrates a cross-section of Figure 6b.

Figure 6d - illustrates another embodiment of the same aspect of the 20 invention as in Figure 6b.

Figure 6e - illustrates another embodiment of the same aspect of the invention as in Figure 6b.

Figure 6f - illustrates a variation of the embodiment of Figure 6e.

Figure 6g - illustrates another embodiment of the same aspect of the 25 invention as in Figure 6b.

Figure 7a - illustrates a further embodiment of Figure 6b in the unlocked position.

Figure 7b - illustrates the embodiment of Figure 7a in the locked position.

Figure 8a - illustrates another embodiment of Figure 6b in the unlocked 30 position.

Figure 8b - illustrates the embodiment of Figure 8a in the locked position.

Figure 9 illustrates an embodiment of the security system of the present invention.

Figures 1a and 1b illustrate typical manhole and pit covers which are used in Australia and throughout the World. Figure 1a illustrates the metal 5 variety of manhole cover 10a with conventional key access hole 11a. The conventional key (not shown) is inserted into the hole 11a and rotated enabling the manhole cover to be lifted open. Figure 1b illustrates the concrete variety of pit cover 10b also with conventional key access hole 11b. As with the manhole cover 10a of Figure 1a, the conventional key (not shown) is inserted into the 10 hole 11b of pit hole cover 10b and rotated enabling the pit hole cover to be lifted open.

Thus, the present invention deals with limiting general access to the pit or manhole by providing a novel security system.

Figure 2 is directed to one aspect of the present invention. Pit / manhole 15 cover 10 covers pit / manhole defined by the pit / manhole wall 40. Provided underneath the pit / manhole cover 10 is a locking/latching mechanism comprising components 30 and 31. Latch actioning means 30 is connected to spring latch arms 31. The latch actioning means 30 is preferably rotatable and in Figure 2 is attached to the underside of cover 10 via housing means 32. 20 Housing means 32 allows the latch actioning means 30 to rotate. Preferably, the latch actioning means 30 has a hole or recess 34 which is similarly positioned underneath a hole or recess (11) in the manhole cover (10). The hole or recess (11) can be an access hole or in the case of covers for sewage pipes etc., the hole or recess (11) can be a vent hole. Thus, advantageously, when the 25 manhole cover (10) is viewed from above, there is no apparent security system. To the passer-by, the manhole cover 10 appears to be unrestrained and if entry is attempted the locking mechanism is not apparent.

The spring latch arms 31 are operatively connected to the latch actioning means 30 and at their other ends cooperate with the pit / manhole wall or frame 30 40. The spring latch arms 31 are constructed such that they can be placed under compression. Because of the nature of the spring latch arms 31, the manhole cover 10 can be retained in situ in a recess or recess frame, even 24762 fi 7 when there is a wide tolerance of size. Similarly, because of the spring arrangement, the manhole cover 10 is retained in position when subjected to severe vibration or deformation due to machinery or foot and vehicular traffic.

It can be seen from Figures 2, 3a and 4a that the sprincr latch arms 31 5 have protrusion means 33 attached or formed on the ends thereof. In the / sfiownl'tfie protrusion means 33 is in the "hat" form and is placed and/or formed on the end of the spring latch arms 31. A support means 35 supports the spring latch arms 31 and protrusion means 33 on the manhole or pit "wall" side of the actual protrusions 37. The protrusion means 33 when it is in the "hat" form may 10 have extra gripping means 38 on its wall contacting surface. Reference is now made to Figure 4b wherein another form of protrusion means 36 is illustrated. These protrusion means 36 are protrusions on the spring latch arms 31 and function the same way as the protrusion means 33 . In this case gripping means (not shown) may be applied to the spring latch arms 31.

With reference to Figure 2 again, it should be noted that the protrusion means 33 / spring latch arms 31 can pressure contact the wall of the pit or manhole 40 (left-hand side of Figure 2) in the manner of a latch or be recessed into the wall 40 (right-hand side of Figure 2) thereby strongly jamming the cover or lid into position over the manhole or pit.

Figures 3a and 3b illustrate more clearly the function of the protrusion means 33. Figure 3b illustrates the locking system in the "locked" position, in situ, as in the case of Figure 2 applied to a cement cover. In the "locked" position the spring latch arms 31 are under compression and it is the force of the spring action of the latch arms 31 against the wall 40, directly or via the 25 protrusion means 33, that holds the cover 10 in place. As can be seen in the "locked position", the protrusions 37 do not contact the support 35. It should be noted that the support 35 may be moulded (in the case of cement) or cast (in the case of metal) into the manhole or pit cover 10 or they may be a separate piece construction.

As can be seen in Fig. 3a (unlocked position), the protrusions 37 of the protrusion means 33 are contacting the support 35. By having the protrusion means 33 and support 35, the latch actioning means 30 can only rotate back the prescribed amount, thus advantageously enabling the key to be reinserted into the access hole 11 and engage the latch actioning 5 means 30 easily. If the protrusion means 33 and support system 35 were not present, the latch actioning means 30 would rotate to any position making the reinsertion of the key into the latch actioning means 30 in the correct position very difficult and replacing of the cover 10 in situ, would be awkward for one person to .manage.

In the preferred embodiment illustrated in Figures 4a and 4b, spring latch arms 31 have a curve shape and most preferably an "S" configuration to enable the arms to act as a spring and thus enable compression of the bars. Other shapes which provide the same action can be used; however, the "S" shape is preferred. The system of the present invention is particularly simple in design, 15 relying upon simple co-operation between spring latch arms 31 and latch actioning means 33. Installation and maintenance time and costs are reduced significantly without any loss in effectiveness in securing the manhole or pit. In fact, the spring arm arrangement of the present security system is substantially more reliable than prior art systems because of the simplicity of the system but 20 also because it allows for more variations in the surroundings.

Also in the preferred embodiment, it can be seen from Figure 4b in particular, that the spring latch arms 31 are connected to the latch actioning means 30 in an "over-centre" arrangement. Thus, once the locking mechanism is in a locked position, the only way to release the spring latch arms 31 from their 25 engagement with the pit / manhole wall or frame 40 is by rotating the latch actioning means 30. That is, unlike prior art mechanisms, the spring latch arms 31 cannot be disengaged from the locked position by simply pushing on the spring latch arms 31, since the latch actioning means 30 will not rotate. Furthermore, the combination of the spring latch arms 31 and the "over centre" 30 mechanism provides a particularly secure locking arrangement, wherein both features of "spring arms" and "over centre" prevent the latch arms 31 moved out of position.

The system can be made of metal or plastic and Figure 5 illustrates a plastic form of this aspect of the invention with latch actioning means 50 and latch arms 51 held onto cover 10 by support 52. This embodiment works in a similar manner to that described in relation to the embodiment described in 5 relation to Figure 2. It is noted that latch arms 51 can also withstand being compressed, however, it is expected that for the plastic form, the latch arms 31 will be a different shape and are preferably made up of multiple arms as illustrated. Support means 55 and protrusion means 53 operate in a similar manner to support means 35 and protrusion means 33.

Figure 6a illustrates an example of the prior art. The plug 19 fits into the likes of access or vent holes 11a and 11b; however, due to its construction the plug 19 can easily be removed and the public has easy access to the lifting handle keyhole (which are also access or vent holes 11a or 11b) and therefore the manhole or pit.

Figures 6b and 6c illustrate one form of another aspect of the invention. The device generally indicated 20b is comprised of a first resilient means 21b and second means 22b. The device 20b is inserted into the lifting handle keyhole (11a and 11b). However, to be inserted a second means 22b must be in its "loose", that is not in its "fixed" form. After the device 20b is inserted into the access hole, the second means 22b is pushed into its "fixed" position. The bottom portion of 21 b is pushed outwards and thus forcing 21 b up against the hole, making the removal of device 20b from the hole extremely difficult.

Figure 6d illustrates another form of the same aspect of the invention as Figure 6b. Figure 6d has a first resilient means 21 d and second means 22d.

However, second means 22d is attached to first resilient means 21 d via support means 23. Thus, essentially, second means 22d is hinged to the first resilient means 21 d via 23. The other side of second means 22d can be "loose" or "fixed" into position such that the device 20d is fixed or otherwise into the access holes 11 a or 11 b of the manhole or pit cover.

Figures 6e and 6f illustrate other forms of the same aspect of the invention as Figure 6b. Figures 6e and 6f illustrate the device of the invention made of /■ -9 u plastic. The first resilient means is denoted as items 21 e and 21 f and second means, items 22e and 22f.

In Figure 6e, in order to "fix" the device 20e in position within access holes 11a or 11b, second means 22e is pushed in the downwards direction. To 5 disengage the device 20e, the second means 22e is pushed even further in the downward direction to a narrower portion of 22e.

In Figure 6f, in order to "fix" the device 20f in position within access holes 11a or 11b, second means 22f is pushed in the downwards direction until, the first means 21 f is jammed in. To disengage the device 20f the second means 10 21 f is pulled in the upwards direction, by the use of a key (not shown) and in a similar manner discussed in relation to Figures 8a and 8b.

Figure 6g illustrates a plastic form of the same aspect of the invention as Figure 6b. The first means 21 g is shaped such that it fits into access hole 11a. Second means 22g operates in a similar manner to Figure 6f wherein second 15 means 22g is pushed in a downwards direction until the first means 21 g is jammed into the access hole 11a. To remove the device, second means 22g is pulled in an upwards direction, by the use of a key (not shown) and in a similar manner discussed in relation to Figures 8a and 8b.

Figures 7a and 7b illustrate a further embodiment of this aspect of the 20 invention, however, in this embodiment, first resilient means 721 has an opening in its upper portion to receive second means 722. As with the other embodiments in the locked position (Figure 7b) the second means 722 expands the first resilient means 721. The operation of this embodiment is similar to the embodiment illustrated in Figures 8a and 8b which is discussed below. 25 Figures 8a and 8b illustrate a device 820 which is very similar to the device 720 illustrated in Figures 7a and 7b but designed to fit into the cement/concrete manhole covers. Device 820 consists of first resilient means 821 and second means 822, wherein second means 822 has lug 823. In operation the worker places the device 820 (as shown in Figure 8a) in the hole 30 (11) of the manhole cover (10) and then, with his foot or hand pushes the second means 822 into first resilient means 821, which results in substantially jamming the device 820 into the hole 11 and having the flush appearance to a 11 passer-by as illustrated in Figure 8b. To remove the device 820 a key (not shown) is used. The key (not shown) is inserted into the small hole 824 (724 on Figures 7a and 7b) of the second means 822. The hole 824 passes through the body of the second means 822. The key (not shown) which is shaped the same 5 as hole 824 is pushed through hole 824 until the head portion of the key has passed through hole 825 in the first resilient means 821. The key is then rotated, in this case, 180 degrees and pulled in the upward direction. Second means 822 is also pulled upwards thus unjamming the device 820. Continued pulling of the key (not shown), allows lugs 823 to act on the first resilient means 10 821, thus pulling the entire device 820 out of the hole 11. To reinsert the device 820, the device 820 is inserted into the hole 11 and in this case, second means 822 is trod upon. The device 820 can be removed and inserted as often as required.

Figure 9 illustrates the security system of the invention utilising all of the 15 aspects of the invention simultaneously. As can be seen from Figure 9, device 20 fits into access hole 11 and preferably also into the hole 34 of latch actioning means 30.

To open the manhole cover from the locked position illustrated in Figure 9, the device 20, which as illustrated is similar to device 820 of Figures 8a and 20 8a, is removed. A key (not shown) for the device 20 is used to lift up the second means 822 and thus unjam the device 20. Device 20 is then removed in a manner discussed in relation to Figures 8a and 8b. A conventional manhole / pit cover key (not shown) is then inserted into access hole 11 and into recess 34 of the system of the present invention. The manhole / pit cover key is shaped such 25 that it engages with recess 34 and upon rotation similarly rotates the latch actioning means 30 and allows the spring latch bars 31 to decompress and retract. With the spring latch bars 31 retracted, the manhole / pit cover can be lifted using the same key.

When the manhole / pit cover is out of position and the key has been 30 removed, the spring latch bars 31 are maintained under compression with the aid of protrusion means 33 (36) and support means 35. This system advantageously ensures that the recess 34 and the access hole 11 remain 12 aligned and thus allowing the conventional key (not shown) to be easily reinserted into the access hole 11, and the recess hole 34 of the latch actioning means 30 when the manhole / pit cover 10 is to be re-locked.

Once the manhole / pit cover 10 is in position over the manhole or pit the 5 key (not shown) is rotated, rotating the latch actioning means 30 and engaging the spring latch arms 31 in pressure contact with the pit wall 40 or a recess therein.

Thus, this particular aspect of the invention provides a secure means of protecting the contents of the pit / manhole from the public, but to those who 10 need to gain access provides a one step simple action using a conventional key means. Thus, no retraining of operators is required nor is there a need for any special or new tools. Additionally, due to the simple action of the mechanism, importantly, no extra time is required to release or fit the covers.

The device 20 can then be replaced in the hole 11 and if it is of the type 15 illustrated in Figures 8a and 8b it is trod upon, leaving a flush surface.

It should be noted that in an emergency the security system can be operated from underneath and in most cases emergency keys may be provided within the pit or manhole.

The system of the present invention is cheaper than existing complicated 20 systems to manufacture and fit, wherein the system can be economically retrofitted to existing manhole covers and pit lids in common use since no modifications to manholes or pits or frames therein are required. Similarly, the system can be cost effectively fitted at the time of manufacture of the cover or lid. The system is particularly reliable because of its simplicity but also because of 25 its ability to withstand large variations in the pit / manhole walls or frames and the environments thereof.

In combination, the aspects of the Invention provide a simple, reliable, unique and effective security system, however, it is envisaged that each of the aspects of the invention can be used separately and still provide a more reliable 30 and effective security system than is previously known.

Claims (11)

24762 13 WHAT I CLAIM IS: l

1. A security system for a cover for a manhole or a pit comprising a latch actioning means, and at least two spring latch arms operatively connected to said latch actioning means, wherein said spring latch arms are retained under compression when the cover is in a closed position of use overlying said manhole or pit.

2. The security system of Claim 1, wherein the latch actioning means is rotatable.

3. The security system of Claim 2 wherein said latch actioning means is rotatable between a first position where said security system allows removal of the cover from the manhole or pit and a second position where said security system prevents removal of the cover from the manhole or pit, said latch actioning means being required to rotate against compression forces applied to said latch actioning means by said spring latch arms when moving from said second position to said first position.

4. The security system of any one of Claims 1 to 3, wherein each said spring latch arm has an outer end adapted, in use, to engage against abutment means surrounding said manhole or pit cover and an inner end engaging with said latch actioning means, each said spring latch arm providing a compressive force against said latch actioning means and said abutment means when the manhole or pit cover is in position.

5. The security system of Claim 4, wherein the spring latch arms include at least one section along its length displaced laterally relative to a line through said outer and inner ends.

6. The security system of Claim 5, wherein said at least one section of each said spring latch arm includes a curved portion. 14

7. The security system of Claim 6, wherein the curved portion comprises an "S" formation curve. t

8. The security system of Claim 6, wherein the at least one section includes two laterally displaced arm portions.

9. A manhole or pit cover comprising a cover member including a lifting hole located therein, a securing system for the manhole or pit cover according to any one of claims 1 to 8 wherein the latch actioning means located beneath said lifting hole and accessible through said lifting holes, at least two spring latch arms operatively connected to said latch actioning means at an inner end with each said spring latch arm having an outer end engageable, in use, with abutment means surrounding said manhole or pit cover whereby a compressive force is applied to said latch actioning means and said abutment means by each said spring latch arm.

10. A manhole or pit cover comprising a cover member including a lifting hole located therein, a securing system for the manhole or pit cover according to any one of claims 1 to 8 wherein the latch actioning means is rotatable and located beneath said lifting hole and accessible through said lifting hole, at least two spring latch arms operatively connected to said latch actioning means at an inner end with each said spring latch arm having an outer end engagable, in use, with abutment means surrounding said manhole or pit cover whereby a compressive force is applied to said latch actioning means and said abutment means by each said spring latch arm, the inner ends of said spring latch arms being arranged such that an externally applied inward force on said spring latch arms urges rotation of said latch actioning means in a direction opposite to that necessary to release said outer ends from engagement with said abutment means. 247626 15

11. A manhole or pit cover according to Claim 9 or Claim 10 wherein the lifting hole'in the manhole or pit cover has therein a first resilient means adapted to fit into said hole and a second means which cooperates with said first resilient means and is adapted to expand said first resilient means so as to form an interference fit in said lifting hole thereby obstructing removal of said first resilient means from said lifting hole. GRAHAME GEORGE KERMONDE By his Attorneys BALDWIN, SON & CARffEv