Manhole cover and locking device for such a manhole cover

Abstract

Manhole cover comprising a frame (2) enclosing a manhole access opening, a cover (3) pivotally connected to the frame (2) for opening and closing the manhole access opening, at least one damping element (5, 5.1) at least partially absorbing the weight of the cover (3) in an open position, and a folding safety device (6) with a locking device (7) pivotally connected to the cover (3) and with a frame-side abutment (10) on which the locking device (7) is supported in the event of a folding safety device, characterized in that the manhole cover (1) has an intervention protection device (19) by which, when the cover (3) is open, manual intervention between the locking device (7) and the upper end of the frame (2) and the inside of the cover (20) is blocked, and in that the locking device (7) has an actuating structure (17) for moving the locking device (7) out of its folding safety position on the abutment (10).

Description

[0001] The invention relates to a manhole cover comprising a frame enclosing a manhole access opening, a cover pivotably connected to the frame for opening and closing the manhole access opening, at least one damping element at least partially absorbing the weight of the cover in an open position, and a closing safety device with a locking device pivotably connected to the cover and with a frame-side abutment on which the locking device is supported in the event of a closing safety device.

[0002] Manhole covers are required to provide access to underground facilities. Such access shafts are needed, for example, for maintenance or inspection work. At gas stations, manhole covers are used to close off access to the underground fuel tanks, which must be opened and closed again during each filling process.

[0003] Such a manhole cover has a frame that is connected to the surrounding ground, for example concrete. The frame itself is typically made up of steel components. A cover is hinged to this frame and can be used to close the manhole access opening enclosed by the frame. Such a cover is designed to be robust in terms of its load-bearing capacity so that it can withstand material traffic, such as trucks, rolling over the cover. As a result, such a cover is quite heavy. To facilitate opening and closing, such manhole covers typically have at least one damping element, for example a gas pressure spring, arranged between the frame and the cover to at least largely absorb the weight of the cover. The cover can then be opened and closed with little effort.

[0004] Such a manhole cover also features an anti-slam feature. This supports the lid in its open position against the frame. This is intended to prevent the lid from slamming shut in the event of defective gas springs, i.e., gas springs that cannot or no longer hold the lid in its open position. Such an anti-slam feature has a stay that is hinged to the inside of the lid and, in its used position with the lid open, is supported at its other end by an abutment on the frame. When the lid is open in its used position, the stay extends between the lid and the frame, at a sufficient distance from the hinge axis to ensure that the lid's weight can be safely absorbed.When the lid is in the open position, the end of the stop is positioned so that it either rests against an abutment or, in the event of a lid closing movement, is brought into contact with the abutment. For this reason, the lid can only be closed if the stop has first been swung out of this position. To do this, grasp the stop with one hand while the other hand holds the lid and swings it in the closing direction. However, if the gas pressure springs are defective, the lid may close unexpectedly, with the result that there is a risk that the hand grasping the stop will become trapped. This poses a significant risk of injury.

[0005] Based on this discussed prior art, the invention is therefore based on the object of developing a manhole cover of the type mentioned above in such a way that even if the cover unexpectedly closes, the risk of injury during the necessary handling of the locking device when closing the cover is avoided.

[0006] This object is achieved according to the invention by a manhole cover of the generic type mentioned above, in which the manhole cover has an intervention protection by which, when the cover is open, manual intervention between the locking device and the upper end of the frame as well as the inside of the cover is blocked and in which the locking device has an actuating structure for moving the locking device out of its folding-shut position on the abutment.

[0007] In this manhole cover, the stop has an actuating structure by which it can be grasped and moved out of its support arrangement without the stop having to be manually reached behind. This manhole cover also has an anti-tamper feature which, when the cover is open, blocks manual intervention - i.e. reaching into the space between the stop and the inside of the cover as well as the upper end of the frame. This ensures in a simple but particularly effective way that the stop cannot be manually reached behind or around from the frame side. The fact that the stop has a separate actuating structure, which is typically designed as an opening, enables a person who wants to close the manhole cover by lowering the cover to move the stop out of its support arrangement using a tool.A locking key, for example, can be used to operate the locking elements that lock such a lid to the frame in its closed position. This means that the tool already available can also be used to adjust the locking mechanism required to close the lid. Another advantage of this is that there's no need to bend or kneel to manually grasp and pivot the locking mechanism, as is traditionally the case, and then close the lid.

[0008] Such an anti-tamper device can, for example, be arranged protruding from the inside of the cover. However, a preferred embodiment provides for the anti-tamper device to be mounted on the locking device. With such a configuration, it is easily possible to replace the existing locking device on existing manhole covers with one featuring an anti-tamper device.

[0009] The anti-tamper device is preferably designed as a plate or strip covering the space between the stop and the top of the frame and the inside of the lid. A preferred embodiment is one in which the stop is made in one piece with this plate.

[0010] The frame-side abutment for supporting the locking device of the anti-closing device can, for example, be provided by a bolt protruding from the inside of the frame into the shaft access opening. With such a design, the locking device has a guide recess in its section closest to the cover, into which the abutment bolt is inserted when the cover is closed. This allows the intervention protection, designed as a plate, to be designed so that it largely fills the space between the locking device and the cover or frame, at least to the extent that manual intervention is effectively prevented. In addition, this provides the locking device with a certain degree of guidance or fixation in the vertical direction when the cover is in the closed position. In a further development of such a design of the manhole cover, the abutment bolt is equipped with a bolt head.When the lid is closed, the bolt head is located on the side of the stop facing the shaft access opening, so that when the lid is closed, the stop is additionally held in a horizontal position by a positive fit, both by the head of the abutment bolt and by the inside of the frame. When the abutment bolt engages in the guide recess, the stop is in a defined position without the risk of contacting or even damaging components inside the shaft when the lid is closed.

[0011] The actuating structure of the locking device, which allows it to be released from its support arrangement to close the lid, is designed as an opening, preferably with a width sufficient to accommodate a tool, such as the hook of a locking key. The opening can be designed as an eyelet in the locking device. It is also possible to equip the end section of a guide recess for the abutment bolt in the locking device with a corresponding width, so that this end section forms the actuating structure.

[0012] To minimize the gap between the stay and the inside of the lid or the top of the frame, which must be closed by the anti-tamper device, one embodiment of the stay is curved in an S-shape along its longitudinal direction. The section of the stay closest to the lid has a bulge pointing toward the lid, while the other section bulges toward the shaft access opening, thus giving its opposite side a concave design. In the open position of the lid, this minimizes lateral access to the shaft access opening.

[0013] When providing a frame-side abutment designed as an abutment bolt, a preferred embodiment provides for the abutment-side end of the stay to be equipped with an abutment bolt latch. The abutment bolt engages into this latch when the cover is opened. Such an abutment bolt latch ensures that, when the cover is opened as intended, the abutment bolt is securely inserted into the abutment bolt latch, thus establishing the desired safety function of the stay. For this purpose, according to a preferred embodiment, the stay has a catch hook at its free end as part of its support structure. This catch hook protrudes towards the shaft opening relative to the rest of the underside of the stay and is positioned like a barb. This catch hook also serves to limit the opening movement of the cover.If the lid is opened far enough that the catch hook strikes the abutment bolt or another abutment element, the stopper drops due to gravity with its abutment-side end, causing the abutment bolt to be inserted into the abutment bolt latch. The limit of the abutment bolt latch facing the other end of the stopper then acts as a stop, which, when in contact with the abutment bolt, prevents the lid from closing. A bolt guide can extend from the abutment bolt latch into the stopper, whereby the previously described stop arrangement is only used when the lid cannot be held in its open position by the damping element(s).The lid can then only be closed if it has first been manually pivoted back into its open end position, whereby the abutment bolt is removed from the bolt guide, and then the stopper is lifted at its abutment-side end, thus removing the abutment bolt from the abutment bolt catch. This increases safety when handling the lid, as the support arrangement of the lid on the frame cannot be released simply by moving the stopper from its closed position, but only by additionally pivoting the lid open. If the force required for this is sufficiently large, this is an indication to the person operating the lid that the lid support with the damping element(s), for example designed as gas pressure springs, is not as intended and that a higher lid force is to be expected when closing.

[0014] Instead of an abutment bolt as an abutment, a differently designed abutment can of course also be arranged on the inside of the frame, for example a guide with abutment recesses into which the abutment-side end of the locking device engages with a support bolt.

[0015] The invention is described below using an exemplary embodiment with reference to the accompanying figures. They show: Fig. 1: A perspective view of a manhole cover according to the invention, Fig. 2: an enlarged detailed view of the locking device of the manhole cover of the Fig. 1, Fig. 3: the locking device of the manhole cover of the preceding figures in a perspective view, Fig. 4: the manhole cover of the Fig. 1 from a different perspective and Fig. 5: an enlarged view of the safety device in the perspective of the manhole cover of the Fig. 4.

[0016] A manhole cover 1 comprises a frame 2 and a cover 3 pivotally attached to it. In the illustrated embodiment, the frame 2 is a steel structure composed of several frame profiles. In the illustrated embodiment, the frame 2 is square and encloses a square manhole access opening. When the manhole cover 1 is installed, the frame 2 is connected to the surrounding floor. In many cases, the top side of the frame 2 will be flush or almost flush with the surrounding floor. The cover 3 is also a steel structure and designed to be sufficiently stable so that industrial trucks can roll over it. For this reason, reinforcing ribs are attached to the inside of the cover. The cover 3 is connected to the frame 2 by means of hinges 4, 4.1 and, in its closed position, its top side is flush with the top side of the frame 2.To compensate for the weight of the cover 3, the manhole cover 1 has two gas pressure springs 5, 5.1, which are connected with one end to the inside of the cover 3 and with their other end to the inside of the frame 2.

[0017] The manhole cover 1 also has a locking device, designated overall by reference number 6, which prevents the cover 3 from closing or slamming shut if the gas pressure springs 5, 5.1 are defective.

[0018] The locking device 6 comprises a locking device 7, one end of which is connected in an articulated manner to the inside of the lid. In the illustrated embodiment, a bolt 8, which passes through the locking device 7 and a connecting tab 9 of the lid 3, serves to realize the articulated connection (see also Fig. 2). The required opening in the locking device 7 serves as a connection means in this embodiment. The anti-folding device 6 further has a frame-side abutment, which in the illustrated embodiment is provided by an abutment bolt 10. The abutment bolt 10 is rigidly attached to the inner side 11 of the frame 2 and, in the illustrated embodiment, is equipped with a head 12. In the open position of the cover 3 shown in the figures, the abutment-side end section of the locking device 7 is located between the inner side 11 of the frame 2 and the head 12. In the open position of the cover 3, its weight is absorbed by the gas pressure springs 5, 5.1, and the cover 3 is held in this position.

[0019] The design of the abutment-side end section of the locking device 7 is the Fig. 3. This end section of the stop 7 is designed as an abutment bolt latch 13. The abutment bolt latch 13 has a catch hook 14, which strikes the abutment bolt 10 when the cover 3 is opened, thus limiting its opening movement. The catch hook 14 is part of the mouth of the abutment bolt latch 13. The catch hook 14 is inclined towards the other end of the stop 7 and is thus positioned like a barb, so that when the cover 3 is opened, the abutment bolt 10 is moved into the abutment bolt latch 13. Then, as in Fig. 1 and Fig. 3, the abutment bolt 10 in the abutment bolt trap 13, which in Fig.3 is shown in dashed outline. Starting from the abutment bolt latch 13, a bolt guide 15 is inserted into the latch 7, following the longitudinal extension of the locking device 7. When the gas pressure springs 5, 5.1 function as intended, the cover 3 remains in the position shown in the figures, in which the abutment bolt 10 is located in the abutment bolt latch 13. A stop arrangement for supporting the cover 3 against a closing movement is not present in this position. To close the cover 3, it is only necessary to lift the abutment-side end of the locking device 7 in order to move the abutment bolts 10 out of the abutment bolt latch 13. However, if the gas pressure spring 5, 5.1 can no longer fully compensate for the weight of the cover 3, and the cover 3 naturally closes or folds shut, the abutment bolt 10 is adjusted into the bolt guide 15 in the direction of the abutment bolt 10.The end 16 of the bolt guide 15 then forms a stop, preventing further closure of the cover 3. The bolt guide 15 only needs to be long enough so that, when the abutment bolt 10 is inserted into it, it is vertically trapped. Based on this support arrangement of the cover 3 relative to the frame 2, the cover 3 can only be closed if it has previously been pivoted slightly to move the abutment bolt 10 out of the bolt guide 15, and the locking device 7 has subsequently been raised.

[0020] The locking device 7 further comprises an actuating structure, embodied in the illustrated embodiment as an eyelet 17. The width of the eyelet 17 is adapted to the material thickness of the hook of a locking key, which is used to actuate the locking elements of the cover 3 in its closed position relative to the frame 2.

[0021] The locking device 7 also has a guide recess 18 into which the abutment bolt 10 is inserted at the end of a lid closing process. Thus, even when the lid 3 is closed, the head 12 of the abutment bolt 10 is located on the inside of the locking device 7, so that it remains fixed even when the lid 3 is closed.

[0022] The locking device 7 further comprises an anti-tamper device, embodied as a plate 19 in the illustrated embodiment. The plate 19 is manufactured in one piece with the locking device 7. This plate forms the underside of the guide recess 15. The plate 19 largely fills the space between the inner side 20 of the lid and the upper side 21 of the frame 2. Manual intervention, i.e., intervention with a hand between the locking device 7 and the inner side 20 of the lid or the upper side 21 of the frame 2, is thereby effectively prevented.

[0023] The invention has been described using exemplary embodiments. Without departing from the scope of protection described by the applicable claims, numerous further embodiments for implementing the inventive concept will become apparent to those skilled in the art without the need for further explanation within the scope of these statements. List of reference symbols 1 manhole cover 2 frames 3 lids 4, 4.1 Hinge 5, 5.1 Gas spring 6 Folding lock 7 locking devices 8 bolts 9 Connection tab 10 abutment bolts 11 Inside 12 heads 13 Abutment bolt trap 14 catch hooks 15 Bolt guide 16 End 17 Eye 18 Guide recess 19 plate 20 Inside of lid 21 Top

Claims

[1] Manhole cover comprising a frame (2) enclosing a manhole access opening, a cover (3) pivotally connected to the frame (2) for opening and closing the manhole access opening, at least one damping element (5, 5.1) at least partially absorbing the weight of the cover (3) in an open position, and a closing safety device (6) with a locking device (7) pivotally connected to the cover (3) and with a frame-side abutment (10) on which the locking device (7) is supported in the event of a closing safety device, characterized by that the manhole cover (1) has an anti-interference device (19) by which, when the cover (3) is open, manual intervention between the locking device (7) and the upper end of the frame (2) as well as the inside of the cover (20) is blocked and that the locking device (7) has an actuating structure (17) for moving the locking device (7) out of its folding-shut position on the abutment (10). [2] Manhole cover according to claim 1, characterized by that the anti-interference protection is designed as a plate (19) or strip which prevents manual intervention in the space between the locking device (7) and the upper side of the frame (2) as well as the inside of the cover (20). [3] Manhole cover according to claim 1 or 2, characterized by that the anti-interference device (1a) is part of the locking device (7). [4] Manhole cover according to claim 3, characterized by that the frame-side abutment (10) of the folding safety device (6) is provided by a bolt (10) projecting from the inside of the frame into the shaft access opening and the locking device (7) has a guide recess (18) into which the abutment bolt (10) is inserted when the cover (3) is closed. [5] Manhole cover according to claim 3, characterized bythat the abutment bolt (10) carries a bolt head (12) which, when the abutment bolt (10) engages in the guide recess (18), is located on the side of the locking device (7) facing into the shaft access opening. [6] Manhole cover according to one of claims 1 to 5, characterized by that the actuating structure of the locking device (7) is an opening made in the latter. [7] Manhole cover according to claim 6, characterized by that the opening is designed with a width that allows the hook of a locking key to be inserted into it. [8] Manhole cover according to claim 6 or 7, characterized by that the opening is designed as an eye (17) introduced into the locking device (7). [9] Manhole cover according to claim 6 or 7 in their respective reference to claim 4, characterized by that the end section of the guide recess (18) is the actuating structure designed as an opening. [10] Manhole cover according to one of claims 1 to 9, characterized by that the locking device (7) is curved in an S-shape in the direction of its longitudinal extent, the section closer to the cover being bulged in the direction of the cover (3) when the cover (3) is closed and the other section being bulged in the direction of the shaft access opening. [11] Manhole cover according to one of claims 2 to 10, characterized by that the locking device (7) is equipped at its free end, which serves as a support on the frame-side abutment (10), with an abutment bolt latch (13) into which the abutment bolt (10) engages when the cover (3) is open. [12] Manhole cover according to claim 11, characterized by that the abutment bolt latch (13) has a catch hook (14) projecting from the side of the locking device (7) facing the shaft access opening. [13] Manhole cover according to claim 11 or 12, characterized bythat starting from the abutment bolt latch (13) a bolt guide (15) extending into the locking device (7) is introduced, the end (16) of which forms a stop on the abutment bolt (10) during a folding or closing movement of the cover (3). [14] Manhole cover according to one of claims 1 to 13, characterized by that the manhole cover (1) has two gas pressure springs (5, 5.1) as a damping element. [15] Locking device for a manhole cover (1) having a frame (2) and a cover (3) hinged thereto, with connecting means for the articulated connection of the locking device (7) to the cover (3) of a manhole cover and with a support structure with which the locking device (7) can be supported on a frame-side abutment (10) in an open position of the cover (3), characterized bythat the locking device (7) is equipped with an intervention protection (19) by means of which, when the lid (3) is open, manual intervention between the locking device (7) and the upper end of the frame (2) and the inside of the lid (20) is blocked, and that the locking device (7) has an actuating structure for moving the locking device (7) out of its secured-shut position on the abutment (10), wherein the intervention protection (19) is designed as a plate (19) which prevents manual intervention in the space between the locking device (7) and the top side of the frame (2) and the inside of the lid (20). [16] Locking device according to claim 15, characterized by that the locking device (7) has a guide recess (18) into which the abutment bolt (10) is inserted when the cover (3) is closed. [17] Locking device according to claim 16, characterized by that the actuating structure of the locking device (7) is an opening made in the latter. [18] Locking device according to claim 17, characterized by that the opening (17) is designed with a width such that the hook of a locking key can be inserted into it [19] Locking device according to claim 17 or 18, characterized by that the opening is designed as an eye (17) introduced into the locking device (7). [20] Locking device according to claim 17 or 18, characterized by that the end section of the guide recess (18) is the actuating structure designed as an opening. [21] Lock according to one of claims 15 to 20, characterized by that the support structure of the locking device (7) comprises an abutment bolt latch (13) into which the abutment bolt (10) engages when the cover (3) is open. [22] Locking device according to claim 21, characterized by that the abutment bolt latch (10) has a catch hook (14) projecting from the side of the locking device (7) facing the shaft access opening. [23] Locking device according to claim 21 or 22, characterized by that starting from the abutment bolt latch (13) there is provided a bolt guide (15) extending into the locking device (7), the end (16) of which forms a stop on the abutment bolt (10) during a folding or closing movement of the cover (3).

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