FI67905C - ANORDNING FOER LAOSNING AV BRUNNSLOCK - Google Patents

Description

1 67905

Device for locking the manhole cover - Anordning för läsning av brunnslock

The present invention relates to a device for locking a manhole cover against the wall of a manhole or similar well, the locking device comprising locking pieces to be handled above the cover, each located in its own plurality of cavities arranged in the circumference of the manhole cover.

For example, manhole covers arranged on top of manholes and the like can often be detached because, due to their weight, the locks can be expected to remain in place even when vehicles pass over them. However, if the contact or abutment surface between the lid and the well is uneven, as is often the case, the lid will easily start to sway. For this reason, in many cases, the lid must be locked in the well to prevent rattling and noise. For safety reasons, it is also advisable to equip manhole covers with some kind of locking device to prevent the lid from rising accidentally.

For example, known manhole cover locking devices have required that the covers be provided with hooks or hooks which, by means of a bayonet or quick fastening, are brought into co-operation with corresponding hooks arranged in the circumference of the well. Additional examples are locking tongue or locking barrier devices which are made to protrude from above the cover into grooves made in the circumference of the well for this purpose. In practice, known locking devices have not achieved widespread use due to the complex structure on the one hand and the fact that the locking mechanism has failed due to rust or accumulation of dirt on the other hand.

The locking device according to the present invention provides a structure which satisfies the requirement of assembly and disassembly well and at the same time realizes the main object, i.e. effective locking.

To achieve these objects, the invention has the features set out in the following claims.

The invention will be explained in more detail below with reference to the drawing, in which:

Figure 1 is a vertical section of the peripheral portion of the lid at the edge of the well.

Figure 2 is a section along the line A-A in Figure 1.

A number of keyways 2 are arranged on the circumference of the well cover 1. A keyway 3 is formed in each keyway, the protrusion of which in the circumferential direction is limited by two keyway ends 4a, 4b. The wedge path 3 extends obliquely towards the circumference of the cover 1 so that together with the inner surface 6 of the well circumference 5 it forms a downwardly tapering groove. The central groove 7, the purpose of which will be explained below, is located in the keyway 2 and divides the keyway 3 into two parts.

To lock the cover 1 against the well ring 5, a locking piece in the form of a roller 8 is used. The locking force is obtained by placing the locking piece 8 between the inner surface 6 of the well ring 5 and the keyway 3 and by pressing or knocking it down until a certain initial tension is reached. As the cover 1 moves upwards, the locking piece rolls down while the space for the locking piece 8 decreases due to the inclination of the wedge tracks 3, whereby the locking force increases strongly even when the inner surface 6 of the well ring 5 has a tilt according to Fig. 1.

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To prevent the locking piece 8 from falling into the well, if the cover 1 is placed non-centrally in the maximum size of the well, a bead 9 is formed at the lower end of each wedge track 3. The angle of this key to the locking piece

The ends 4a, 4b of the keyways 2 have three functions: - Reinforcing the keyways 3 - Preventing the locking piece 8 from moving out of the correct position - Forming a guide when placing the cover 1 in the well.

Assembly and disassembly can be accomplished with a simple tool, such as a bar, that is installed to strike the locking piece down. When disassembled, the lever end protrudes into the groove 7 and the locking piece can then be unscrewed.

The device according to the invention achieves the best possible corrosion protection, because only cast iron is used and there is no risk of stress corrosion.

Claims (3)

4 67905 A device for locking a manhole cover (1) against a wall (6) of a sewer or a similar manhole, the locking device comprising locking pieces to be treated above the cover (1), each of a plurality of cavities arranged in the periphery of the manhole cover (1), characterized by two cavity walls (3, 6) converges downwards from the upper surface of the cover (1), and that of these surfaces (3, 6) that in the well cover (1) is planar and forms a wedge track (3) with a centrally located groove (7), The tapered space between (3) and the manhole cover (6) has a locking piece in the form of a roller (8). Device according to claim 1, characterized in that each wedge path (3) is delimited by two ends (4a, 4b). Device according to Claim 1 or 2, characterized in that a ball (9) is formed at the lower end of the wedge track (3). Il