FIELD OF THE INVENTION

The invention relates to a device and a system for securing an object to a frame for a manhole cover.

BACKGROUND OF THE INVENTION

Certain types of manholes, for example a manhole comprising a valve for a water supply pipe, may not be provided with integrated steps. In other type of manholes integrated steps may not be provided due to the design of the manhole, for example wherein the manhole entrance is narrower than the manhole so that the inner walls of the manhole have a slope, or the inner walls of the manhole are spaced apart from the entrance by a horizontal roof. During inspection or service of such a manhole or equipment housed within the manhole, it is common to lower a ladder into the manhole to enter the manhole. The manholes are typically narrow, at least at its opening in the top portion, and the lowered ladder may make the manholes narrower, making it even more cumbersome for an operator to enter the manhole. It may also be difficult to support a conventional ladder on a bottom portion of a manhole since the bottom portion may comprise open channels, pipelines, valves etc. Thus, the manhole may have an uneven bottom leading to an unstable positioning of the ladder on the uneven bottom. The ladder may wobble when an operator is using the ladder. Furthermore, the ladder may be long, heavy, and burdensome to transport. Other type of equipment is also commonly used when work is performed in a manhole. A crowbar is commonly used for removing the manhole cover to gain access to the manhole. A lamp may be suspended from a support for lighting up the manhole. A hoisting device may also be suspended from a support so that the hoisting device is positioned above the manhole. The hoisting device may be used for lowering and lifting equipment, concrete, or gravel into and from the manhole. It may also be used as a fall protection for an operator entering the manhole, or for rescuing a person from the manhole. It is therefore important that the hoisting device is properly secured to a support that is stable enough to carry the load. The support is therefore typically large and heavy.

Publication DE29811997U1 discloses a device for facilitating rapid coupling to an entry point such as for example a manhole. The device comprises a clamping ring with a tensioning device for detachable coupling to the entry point. The tensioning device comprises a spindle to which a stepladder and/or a support device can be coupled.

Publication US 4,355,701 A discloses a ladder assembly that includes a supporting bracket to pivotally mount one end of a ladder member.

Publication US 10,214,345 Bl discloses a device for that is removably placed about a manhole to form a continuous surface that lacks sharp edges.

SUMMARY OF THE INVENTION

The invention has for its object to remedy or to reduce at least one of the drawbacks of the prior art, or at least provide a useful alternative to prior art.

The object is achieved through features, which are specified in the description below and in the claims that follow.

The invention is defined by the independent patent claims. The dependent claims define advantageous embodiments of the invention.

In a first aspect the invention relates to a device for securing an object to a frame for a manhole cover. The device comprises:

- a body having an outer portion, an inner portion, a bottom portion, and a top portion, wherein at least a portion of the body is, in a position of use, configured for immovably resting on the frame; and

- at least one coupling element secured to the inner portion of the body, wherein the at least one coupling element is configured for carrying the object. The at least one coupling element comprises a recess for receiving a portion of the object.

By immovably is here meant that the body cannot be displaced sideways relative to the frame, so that the device cannot fall into the manhole. The body may still be rotated, for example.

The device according to the first aspect of the invention may be used during inspection or service of a manhole. Different equipment such as a ladder, a hoisting device, a lamp, etc. may be used during these operations. The equipment typically needs support structures around the manhole for supporting the hoisting device or the lamp above the manhole. Using the device according to the invention, the equipment may be fastened to an object and the object may be secured to the frame for the manhole cover. This may be more convenient as it frees up space around the manhole. It also results in less weight to be transported to the manhole due to the reduced need for extra support structures. The device in itself may also be less cumbersome to transport due to the size and weight compared to common support structures.

The advantage of securing the at least one coupling element to the inner portion of the body is that the coupling element can be used to carry an object extending into the manhole. The object may for example comprise steps so that it functions as a ladder.

The device may comprise two or more coupling element secured to the inner portion of the body, wherein each coupling element is configured for carrying an object.

In an embodiment of the device, at least a part of the bottom portion of the body is configured for, in a position of use, abutting against a shoulder of the frame.

A frame for a manhole cover typically comprises a shoulder for the manhole cover to rest on. This shoulder may conveniently be used for supporting at least a part of the bottom portion of the body.

In a further embodiment, the bottom portion of the body is configured for, in a position of use, abutting against a shoulder of the frame.

In a further embodiment, at least a part of the outer portion of the body is configured for, in a position of use, abutting against a vertical portion of the shoulder of the frame.

In a further embodiment, at least a part of the top portion protrudes beyond the outer portion of the body, so that the protruding top portion is above a top portion of the frame.

In an embodiment of the device, at least a part of the top portion of the body is configured for, in a position of use, being flush with a top surface of the frame.

It may be advantageous that the top portion of the body does not extend higher than the top surface of the frame when the body is resting on the frame. An operator may not need to step over an edge or barrier when entering or leaving the manhole when the body of the device is resting on the frame. Avoiding a barrier facilitates entering of the manhole and may thus represent an important safety aspect for the operator.

However, the top portion of the body may, in a position of use, be somewhat higher or lower than the top surface of the frame. By somewhat is meant a few centimetres, for example 2-5 centimetres higher than the top of the frame.

In an embodiment of the device, at least a part of the inner portion of the body is configured for, in a position of use, being flush with an inner surface of the frame.

Manholes are typically narrow, so it may be advantageous that the inner portion of the body does not extend beyond the inner surface of the frame. If the inner portion of the body is flush with the inner surface of the frame, or if the edge between the inner surface and the shoulder extends beyond the inner portion of the body, no extra space within the manhole is taken up by the body when it is resting on the frame. In a preferred embodiment of the device, the top portion of the body is configured for, in a position of use, being flush with a top surface of the frame, and the inner portion of the body is configured for, in a position of use, being flush with an inner surface of the frame. Thereby, the device does not represent any obstruction, while at the same time having a maximum load-distributing area against the shoulder of the frame.

In an embodiment of the device according to the invention, the body comprises two parts. The two parts may be equal or unequal in size. This may facilitate transport of the device. The two parts may comprise complementary locking mechanisms for locking the two parts together.

In another embodiment of the invention, the body is endless and has a circular shape. Manholes may typically be circular, and frames for covers for these manholes are also circular. For this type of manholes it is advantageous that the body has a circular shape, matching the shape of the frame for the manholes in such a way that the device cannot fall into the manhole.

In another embodiment of the invention, the body is endless and has a rectangular shape. Manholes may be rectangular, and frames for covers for these manholes are also rectangular. For this type of manholes it is advantageous that the body has a rectangular shape.

The body may comprise hinges for folding the body. This is advantageous during transport since a folded body is less space-requiring. Preferably the hinges are arranged so that bottom portions of the body only fold towards each other. Arranging the hinges in this way, may reduce unintentional folding of the body during installation or removal.

In an embodiment of the invention, a lowest point of the recess is at the same level of elevation as the top surface of the frame for the manhole cover. Alternatively, a lowest point of the recess is at the same level of elevation as the top portion of the body.

The object to be carried by the coupling element may comprise at least one rod that is configured for being received within the recess. The rod may in one embodiment abut against the top surface of the frame. This distributes the weight of the object between the coupling element and the frame. The lowest point of the recess may, as mentioned above, also be at the same level of elevation as the top portion of the body, so that the rods may abut against the top portion of the body. The weight of the object may then be distributed between the coupling element and the body. In a preferred embodiment the lowest point of the recess is at the same level of elevation as the top surface of the frame and at the same level as the top portion of the body. In this case, the rods may abut against the top portion of the body and the top surface of the frame. The weight of the object is in this case distributed between the coupling element, the body, and the frame.

In a second aspect the invention relates to a system comprising the device according to the first aspect of the invention, and an oblong object, having a first end and a second end opposite the first end. The oblong object is provided with engagement means for engaging the at least one coupling element.

The system according to the second aspect of the invention may be used during inspection or service of a manhole. Different equipment such as ladders, hoisting devices, lamps, etc. may be used during these operations. The equipment typically needs support structures around the manhole for supporting the hoisting device or the lamp above the manhole. Using the system according to the second aspect of the invention, the equipment may be attached to or integrated with the oblong object. The oblong object may be carried by the body of the device by engaging the engagement means of the oblong object with the coupling element of the body. This secures the oblong object to the frame for the manhole cover. This may be more convenient as it frees up space around the manhole, as it reduces the need for extra support structures. It also results in less weight to be transported to the manhole. The device and the oblong object may also be less cumbersome to transport due to the size and weight compared to common support structures.

The oblong object may comprise a protrusion configured for, in a position of use, abutting against an inner surface of the frame for the manhole cover. The protrusion may stabilise the oblong object when it is carried by the device. This may be especially advantageous if the oblong object comprises steps and functions as a ladder for entering the manhole or if the oblong object comprises an attachment means for a hoisting device. The protrusion may be configured for keeping the oblong object vertical as weight is applied to the oblong object by an operator or by a load attached to the hoisting device. Preferably, the protrusion is adjustable in length.

The first end of the oblong object may comprise at least one support for a foot of an operator, and wherein the first end of the oblong object is configured for, in a position of use, passing below the frame. In this embodiment of the system, the oblong object may function as a ladder for entering the manhole. The first end of the oblong object may extend substantially vertical below the frame. Thus the oblong object may take up less space within the manhole compared to conventional ladders which typically has a slope when extending below the manhole. The manhole may be narrow, and so it may be easier for an operator to use the oblong object as a ladder as it takes up less space. Furthermore, since the oblong object is resting stably on the body and not on the bottom of the manhole, the oblong object may remain stable also in use regardless of the shape of the bottom of the manhole.

In an embodiment of the system according to the second aspect of the invention, the second end of the oblong object comprises an attachment means for a hoisting device, and wherein the second end of the oblong object is configured for, in a position of use, projecting over a portion of the frame.

The attachment means for the hoisting device may be positioned at the second end of the oblong object projecting over a portion of the frame. The hoisting device may then be positioned above the manhole. The hoisting device may thus be used for various operations, such as lowering and lifting equipment into and out of the manhole, rescue operations, fall protection, etc.

The hoisting device may be a winch or a pulley.

In an embodiment of the invention, one of the first or the second end of the oblong object comprises a means for engaging a portion of a manhole cover. The means for engaging the portion of a manhole cover may be a crowbar for removing the manhole cover from the frame. An oblong object comprising both a crowbar and a support for a foot of an operator may be beneficial as it reduces the need of transporting a separate ladder for work in a shallow manhole.

The engagement means of the oblong object may comprise a rod configured for abutting against at least the top portion of the body when the engagement means is engaged with the at least one coupling element. This is advantageous as the weight of the oblong object is distributed between the coupling element and the body.

In a further embodiment, the rod may be configured for also abutting against the top surface of the frame. This is advantageous as the weight of the oblong object is distributed between the coupling element, the body, and the frame.

The oblong object may comprise at least two engagement means spaced apart between the first and the second end. This enables the adjustment of how far over or below the frame the oblong object is extending.

In an embodiment according to the invention, the system comprises a further oblong object. The oblong objects may be carried by separate coupling elements of the body. An oblong object functioning as a ladder may in this way be used simultaneously as an oblong object carrying a lamp or a hoisting device.

DRAWINGS AND SPECIFIC DESCRIPTION

In the following is described examples of preferred embodiments illustrated in the accompanying drawings, wherein:

Fig. 1 shows a device for securing an object to a frame for a manhole cover;

Fig. 2 shows an alternative embodiment of the device shown in Figure 1;

Fig. 3 shows the device of Figure 1 resting on a frame for a manhole cover;

Fig. 4 shows an oblong object connected to the device, but prior to lowering the device onto a frame for a manhole cover; Fig. 5 shows the same as Figure 4, but more details of the oblong object and the frame for the manhole cover wherein the oblong object comprising a support for a foot;

Fig. 6 shows an oblong object secured to a frame for a manhole cover, seen from above, the oblong object comprising a support for a foot;

Fig. 7 shows the oblong object of Figure 6;

Fig. 8 shows a further alternative oblong object secured to a frame for a manhole cover, the oblong object comprising supports for a foot and several engagement means;

Fig. 9 shows a further alternative oblong object secured to a frame for a manhole cover, the oblong object comprising a lamp; and

Fig. 10 shows a further alternative oblong object secured to a frame for a manhole cover, the oblong object comprising a hoisting device.

Any positional indications such as "upper" and "lower", "top" and "bottom", or "horizontal" and "vertical", etc., denotes the position the apparatus has in the subsequent figures, which is also a natural or practical functional position of the apparatus.

In the figures, same or corresponding elements are indicated by same reference numerals. For clarity reasons, some elements may in some of the figures be with-out reference numerals.

A person skilled in the art will understand that the figures are just principal drawings. The relative proportions of individual elements may also be distorted.

The Figures show a device 2 for securing an object 4 to a frame 5 for a manhole cover. Figure 1 shows the device 2 comprising a body 3 and a coupling element 25. The body 3 has an outer portion 39, an inner portion 31, a bottom portion 32, and a top portion 38. The coupling element 25 is secured to the inner portion 31 of the body 3 and is configured for carrying an object 4 as shown for example in Figure 4. The body 3 is provided with a handle 29 for facilitating handling of the device 2.

The body 3 is shown in Figure 2 in two parts connected with hinges 28. In the embodiment shown, the hinges 28 are configured in such a way that the bottom portions 32 of the two parts of the body 2 meet when the body is folded. Preferably, the body 2 cannot fold the other way, so that the body 2 does not fold when resting on a frame 5 for a manhole cover.

The body 3 shown in the Figures is configured for resting on a shoulder 52 of a frame 5, see for example Figures 3 and 4. The top portion 38 of the body 3 is flush with a top surface 59 of the frame 5. The inner portion 31 of the body 3 is flush with an inner surface 51 of the frame 5. The outer portion 39 of the body abuts against a vertical portion 53 of the shoulder 52. The advantage of this example of the device 2 is that the device 2 is resting stably on the shoulder 52. The device 2 cannot move radially, nor can it fall into the manhole 6.

The device 2 comprises a coupling element 25 secured to the inner portion 31 of the body 3. The coupling element 25 can be seen in a larger scale in Figure 3. The coupling element 25 comprises two brackets 250, spaced apart. The two brackets 250 each comprises a recess 251 that may receive complementary engagement means 43 of the object 4, see for example Figure 4. The engagement means 43 comprises rods 430 on either side of the longitudinal axis of the object 4. The rods 430 are placed within the recesses 251 such that the object 4 is positioned between the two brackets 250.

The recesses 251 may be vertical, as shown in Figure 4. The object 4 can easily be secured to the device 2 by lowering the object 4 between the two brackets 250 and resting the rods 430 in the recesses 251. The loads applied to the object 4 will create a downwards force on the object 4. The rods 430 may therefore not slide upwards and out of the recesses 250. However, an upward force, may lift the rods 430 of the object 4 out of the recess 251. Thus, an unintentional upward force, may represent a potential safety hazard.

To mitigate such a potential safety hazard, the recesses 251 may be horizontal, as shown in for example Figures 8 and 10. To secure the object 4 to the device 2, the object 4 is lowered while being somewhat inclined between the two brackets 250 until the rods 430 are at the same hight as the recesses 251. The object is then brought from the inclined position to an operating position wherein the rods 430 are slid into the recesses 251. When the object 4 is subject to an external load, for example a weight from an operator standing on a support 44 for a foot or a step 44 of the object 4 (Figure 8), the body 3 is prevented from being inclined, and the rods 430 are prevented from sliding out of the recesses 250.

In the example shown in Fig. 1, the recesses 251 have a lowest point 255 that are at the same level of elevation as the top portion 38 of the body 3. The lowest points 255 are in this example at the same level of elevation as the top surface 59 of the frame 5 when the body 3 is resting on the frame 5. In this case, the rods 430 abut against the top portion 38 of the body 3 and the top surface 59 of the frame 5, a shown in Fig. 10.

The two brackets 250 of the coupling element 25 may also comprise apertures 256 for a locking pin 257, see Figure 10. The locking pin 257 prevents outwards tipping of a first end 41 of the object 4 so that the object 4 rest more stably on the device 2 and prevents unintentional movement of the object 4 that may cause the engagement means 43 of the oblong object 4 to disengage with the coupling element 25 of the device 2. The object 4 may also comprise an aperture (not shown) for a locking pin, wherein the aperture is at the same level of elevation as the apertures 256 of the brackets 250 when the rods 430 are resting in the recesses 251. A locking pin may then be positioned through the two apertures 256 of the brackets 250 and the aperture in the object 4, thus locking the position of the oblong object 4.

In the embodiments of the device 2 shown in Figures 1 and 2, the coupling element 25 is also provided with an attachment 26 for a fall arrest block (not shown). An operator with a harness may be fastened to the fall arrest block fastened to the attachment 26 for safety during an operation in a manhole 6.

In Figures 6 - 10 are shown different types of objects 4. The objects 4 are oblong objects

4. In Figures 5 to 7 is shown an oblong object 4 comprising a step 44 at the first end 41. This oblong object 4 may be used to enter a shallow manhole 6, as illustrated in Figure 6.

The oblong object 4 shown in Figure 7 further comprises a protrusion 45 configured for abutting against the inner surface 51 of the frame 5 when the oblong object 4 is secured to the frame 5. This may be advantageous if the oblong object 4 functions as a ladder for entering the manhole 6. The protrusion 45 is in this example configured for keeping the oblong object 4 vertical as weight is applied to the step 44. The protrusion 45 shown in Figure 7 comprises a screw and a nut for adjusting the length of the protrusion 45. The nut is secured to the oblong object 4 for example by means of a weld. The screw may be screwed through the nut and into a hole in the oblong object 4.

The oblong object 4 shown in Figures 6 and 7 comprises, at the first end 41, a gripping means 48 for engaging a portion of a manhole cover. In this example the gripping means 48 for engaging the portion of a manhole cover is a crowbar 48 for removing the manhole cover from the frame 5. The oblong object 4 comprising the crowbar 48 as shown in Figure 7 is a standard tool for removing manhole covers in Norway. The standard tool may be conveniently used as a simple ladder to enter shallow manholes 6 by attaching a support 44 for a foot of an operator.

In Figure 8 is shown a longer oblong object 4 comprising several steps 44. This may be used to enter deeper manholes 6. Furthermore, in this example, the oblong object 4 comprises three engagement means 43 spaced apart along the oblong object 4. How far down the oblong object 4 reaches may be adjusted by using the different engagement means 43 to engage with the coupling element 25 of the device 2. This oblong object 4 is also provided with a handle 47 for facilitating handling of the oblong object 4, and for support when walking down the steps 44.

The example of an oblong object 4, shown in Figure 9, is provided with a lamp 49. The oblong object 4 extends above the device 2, and the second end 42 is projecting over the manhole 6. The lamp 49 may in this way light up the manhole 6.

The example of an oblong object 4, shown in Figure 10, is provided with an attachment means 46 for a hoisting device 465, here shown as a pulley 465. The oblong object 4 extends above the device 2, and the second end 42 is projecting over the manhole 6, so that the pulley 465 is positioned above the manhole 6. The chains 468 running through the pulley 465 are lowered into the manhole 6.

The oblong object 4 shown in Figure 10 is also provided with a protrusion 45 configured for abutting against the inner surface 51 of the frame 5 when the oblong object 4 is secured to the frame 5. The protrusion 45 is in this example configured for keeping the oblong object 4 vertical as loads are attached to the hoisting device 465. The protrusion 45 preferably comprises a screw and a nut for adjusting the length of the protrusion 45, as shown in Figure 7.

The rods 430 may have different lengths. In the example shown in Figure 8, the rods 430 are short. In the example shown in Figure 10, the rods 430 are longer. The rods 430 are in this case abutting against the top portion 38 of the body 3 and the top surface 59 of the frame 5. This results in a more favourable weight distribution. The load of the oblong object 4 and the potential load applied to the oblong object 4 are in this example distributed across the coupling element 25, the body 3 and the frame 5. In the Figures, the body 3 is shown as an endless body with a circular shape. The circular shape is made to fit onto the shoulder 52 of the circular frame 5. However, the body 3 may have any other shape, for example rectangular, suitable for resting on frames having different shapes.

The body may also be resting on the frame 5.

In the Figures, the body 3 is provided with a single coupling element 25. In other examples the body 3 may be provided with several coupling elements 25. It may for example be beneficial to secure an oblong object 4 functioning as a ladder, and an oblong object 4 provided with a lamp 49 or a hoisting device 465 to the same frame 5. It may also be beneficial to secure a warning sign to the frame 5 using the device 2 to warn passing traffic.

The oblong object 4 may have a first end 41 that, while secured to the frame, is extending into the manhole 6, and a second end 42 extending above the frame 5.

It should be noted that the above-mentioned embodiments illustrate rather than limit the invention, and that those skilled in the art will be able to design many alternative embodiments without departing from the scope of the appended claims. In the claims, any reference signs placed between parentheses shall not be construed as limiting the claim. Use of the verb "comprise" and its conjugations does not exclude the presence of elements or steps other than those stated in a claim. The article "a" or "an" preceding an element does not exclude the presence of a plurality of such elements.

The mere fact that certain measures are recited in mutually different dependent claims does not indicate that a combination of these measures cannot be used to advantage.