WO2016133417A1

WO2016133417A1 - Mechanism for prevention of theft of manhole covers

Info

Publication number: WO2016133417A1
Application number: PCT/RS2015/000004
Authority: WO
Inventors: Dragan MAJKIĆ
Original assignee: Majkić Doo Preduzeće Za Proizvodnju, Trgovinu I Usluge
Priority date: 2015-02-18
Filing date: 2015-02-18
Publication date: 2016-08-25

Abstract

The mechanism for prevention of theft of manhole cover includes two screws (3) passed through openings (1.1) made on the middle axis (1.2) of the cover (1) for the manhole (2). Over the screws (3) are pulled springs (4) so that they are loaded between the screw heads (3.1) and the butterfly nuts (5) that are screwed onto the screws (3) and secured by nuts (6). The butterfly nuts (5) are screwed onto the screws (3) which loads the springs (4) until the butterfly nuts (5) attain the level of the groove (2.1) made below the frame (8). The butterfly nuts (5) have stop screws (7). The cover (1) is placed on the frame (8) of the mancover (2) so that the butterfly screws (5) enter the grooves (2.1) below the frame (8). The eccentric key (9) is placed in the holes (3.2, 3.3) of the head (3.1) of the screw (3) and turned so that butterfly nuts (5) lean via the stop screw (7) against the frame (8). After that the butterfly nuts (5) are moved upwards, exerting pressure inside the groove (2.1) until the spring (4) attains sufficient force and presses fast the cover (1) against the frame (8).

Description

MECHANISM FOR PREVENTION OF THEFT OF MANHOLE COVERS

Technical field

The invention belongs to the field of underground or underwater structures.

According to the International Classification of Patents the invention is denoted by the basic classification symbols: E02D29/14 (2006.01) which include revision shaft covers, etc. and E03F5/06 (2006.01) which include street drain covers.

Technical problem

The technology problem is to establish a solution by a mechanism of simple design that would prevent opening and stealing manhole coves, without a special eccentric key, where the mechanism would be mounted on the underside of all types of manhole covers.

State of the art

Various design solutions for securing against theft of covers for sewage, watermains, and other openings of underground installations are well known, but are mainly complicated or do not offer complete protection. In patent specification EP 0391 825 B is described and presented an opening in the pavement whose cover is locked in the frame of the opening on which a framework is placed, containing an insert that is moveable in the framework between the open and closed positions by means of a hinge. The insert can be locked in the open position of locking by moving vertically downwards with respect to the framework. In this position, at the level of the hinge, two blocking surfaces vertically from the insert and the framework are placed one against the other and prevent irregular closure of the insert. In order to unlock the insert prior to re-closured onto the framework, the insert must be lifted so that two corresponding blocking surfaces are out of contact with one another. As the insert is massive, a considerable effort is needed for lifting and takes considerable time. In patent specification RS 50221 B by company SAINT-GOBAIN PAM, FR the problem of closing the hole is solved by a cover that locks. The cover is movable within the frame by means of one of the two hinges which contains one joint of the cover and one joint of the frame, where in the second hinge there is a device for locking, which is adapted for locking and unlocking of the cover in the open position with relative movement of its joint into its corresponding joint in the frame, following one direction radially with the axis of the first hinge. The same company in patent RS 49950 B solves a similar problem, but with pawls that are inserted into each other. Both designs are elaborate and expensive. In patent RS 49985 B, by the same company, a cover is fitted with one lock with a latch and flat tip positioned against sloping surfaces, which enables latching the cover to the frame of the opening. Latching is carried out by a hand tool. The latch does not ensure efficient security against theft, and the design is not simple. There is a known patent application P-2010/0572, "Safety lock that is fitted onto street drain covers, sewage and water mains manholes and covers of other underground installations, for prevention of theft".

The lock design has several embodiments, so that it can be fitted and fixed onto a drain cover, onto existing covers, and that the lock housing is cast integrally with the cover.

The solution with fitting the safety lock in a part of the opening over which a drain cover is placed consists of the assembly of an upper and a lower steel plate that are connected by a screw, so that it can be fitted onto any cover, depending on the thickness of the cover grid. In the upper plate is made an opening for the transit of the key. In the lower plate is made an opening for the placement of the lock that has a turning hook, which enters the drain wall during locking, an opening for the transit of the screw and openings for draining the sludge which possibly passes through the keyhole. In the keyhole is placed a special key that locks or unlocks the lock. The key is made in several variants.

The lock that is fitted onto existing covers, which may be of square or oval shapes, depending on the purpose, consists of a housing that is fixed to the lower part of the cover by screws. The housing is partly divided with two angled dividers, with outlets, made in the interior, forming a hole in the form of swallowtail through which the user inserts the key, at the same time obtaining two unequal spaces by dividers. The key is inserted through the larger keyhole into a smaller compartment, so that it is longitudinally moved, passing through the swallotail opening to a larger space in which a compartment for the lock is made, with a turning hook, which is turned by the key entering the wall of the cover, by which action the cover is locked. In another case the housing of the latch is cast integrally with the cover, and the design and function remains the same as described.

In a further embodiment the solution may be with or without the housing. In the application a solution without the housing is presented, with a built-in lock and hook that is welded onto the grid of the cover, and with a passage made for the key.

The key is of special design and consists of the body, with a holder, and a hollow konical head with a hexagonal base or another form of base. On two konical sides of the head are made two grooves across, for the passing of the key through a swallowtail hole into a space in which there is a lock with a turning hook. The key is made in several variants. It is made of alloy steel featuring high ductility and hardness.

The above described solutions have fairly complicated design and require considerable costs. In order to overcome these shortcomings, a solution in the form of a mechanism is proposed here for preventing theft of mahnole covers.

Description of the essence of the invention

The essence of the invention is in establishing a mechanism for prevention of theft of mahnhole covers, which can be fitted to all types of covers. The mechanism is mounted on the underside of the cover, and is not accessible to thieves that do not possess a special key for its unlocking. The mechanism includes two screws that are passed through two openings made on the middle axis of the cover. Over the screws, to their heads, are pulled springs loaded by butterfly nuts screwed onto the screws. The butterfly nuts are screwed onto the screws until they attain a position level with a groove made in the manhole under the frame which supports the cover. In that position the butterfly nuts are secured by nuts screwed onto the screws next to the butterfly nuts. The butterfly nuts have on themselves stop screws that lean against the frame of the cover and prevent turning of the butterfly nuts. The springs are by this action sufficiently loaded. The cover is placed over the opening and the buttefrly nuts inserted into the grooves under the frame. An eccentric key is placed into the eccentric holes made in the head of the screw and turns the screw until appropriate force is attained in the spring, which presses the butterfly screws onto the grooves and the cover onto the frame. This procedure is carried out with both screws.

Brief description of figures

The invention is comprehensively described through an example of an embodiment, and presented in a drawing in which:

- Figure 1 , shows the mechanism for prevention of theft of a manhole cover, cross-section "A-A" from Figure 2;

- Figure 2, shows view "P" of Figure 1 ;

- Figure 3, shows view "Q" of Figure 1 ;

- Figure 4, show the eccentric key in axonometric view;

- Figure 5, shows the butterfly nut of the mechanism;

- Figure 6, shows view "R" of Figure 5;

Detailed description of the invention

The mechanism for prevention of theft of mahnole covers includes two screws 3, made of stainless steel, that are pulled through two openings 1 .1 made in the middle axis 1 .2 of the cover 1 of the manhole 2 (Figure 2). Over the screws 3 are puled springs 4, made of stainless steel, so that they are by one end supported onto the head 3.1 of the screw 3. Onto screws 3 are then screwed butterfly nuts 5 so that the spring 4 is by the other end supported onto one side of the screw 5. Onto screws 3 are screwed safety nuts 6 so that they are supported onto the other side of the butterfly nut 5. Onto butterfly nuts 5 are screwed stop screws 7. The stop screws 7 are, as well as butterfly nuts 5, made also of stainless steel.

Screwing butterfly nuts 5 over screws 3 is carried out until butterfly nuts 5 attain the level determined by the depth of the frame 8, i.e. the position of the groove 2.1 made in the manhole 2. At this moment the spring 4 is already loaded and then the safety nut 6 is screwed onto the screw 3. This is done on both screws 3. After that the cover 1 is lowered onto the frame 8. By eccentric key 9, which is placed into holes 3.2, 3.3 of the head 3.1 of the screw 3, the screw 3 is turned clockwise, turning by that the butterfly nut 5, until the stop screw 7 hits the frame 8 of the coverl . From that moment on, turning the screw 3 does no longer turn the butterfly nut 5, starting instead to move upwards, i.e. towards the cover 1 and by that increasing the force of the spring, until it is sufficient so that the cover 1 can no longer be moved and lifted. After mounting, into the openings 3.2 on the screw 3 are placed protective rubber plugs to protect against dirt.

Claims

Patent claims

1 . The mechanism for prevention of theft of manhole covers, characterised by, including two screws (3) passed through openings (1.1 ) made on the middle axis (1 .2) of the cover (1) for the manhole (2); the screws (3) over which springs (4) are pulled, which at one end are supported onto the heads (3.1) of the screw, and at the other end onto one side of the butterfly nut (5), which are screwed onto the screws (3); that are at the other side of the butterfly nut (5) supported onto safety nuts (6) screwed onto the screws (3); on the butterfly nuts (5) are screwed stop screws (7) and the butterfly nuts (5) inserted into grooves (2.1) made in the manhole (2) below the frame (8).

2. The mechanism according to Claim 1 , characterised by, that the screw (3) on its head (3.1) has made two holes (3.2,

3.3) for the eccentric key (9) so that the hole (3.3) is in eccentric position with respect to hole (3.2).