Manhole Cover

Abstract

A manhole platform is provided for mounting on an upper slab of a concrete manhole to allow the manhole to be lifted into or out of position and to provide a safe platform on top for users to stand on. The manhole platform has a support plate for mounting on an upper surface of the upper slab to cover an access hole of the upper slab. A clamping bracket is provided that extends downwardly from a lower side of the support plate, through the access hole, to clamp the manhole platform to the upper slab. An actuator is located above an upper surface of the support plate to operate the clamping bracket between a clamping position in which the manhole platform is clamped to the upper slab, and an unclamped position in which the manhole platform can be lifted off of the upper slab.

Claims

1. A manhole platform comprising: a support plate for mounting on an upper surface of a concrete manhole, the support plate having an upper side and a lower side; a clamping bracket extending downwardly from the lower side; and an actuator positioned to be operable from the upper side of the support plate; wherein the clamping bracket comprises an attaching portion and a clamping portion; the attaching portion is attached to the support plate at a proximal end and extends downwardly to a distal end; the clamping portion is attached to the distal end of the attaching portion; the clamping portion is moveable between a clamping position and an unclamped position; in the clamping position the clamping portion has a clamping width in a first direction parallel to the lower side of the support plate; in the unclamped position the clamping portion has an unclamped width in the first direction parallel to the lower side of the support plate; the clamping width is at least 10% greater than the unclamped width; in both the clamping position and the unclamped position the attaching portion has a width that is less than or equal to the unclamped width; the actuator is operable to move the clamping portion between the clamping position and the unclamped position; and a safety cage is formed on the upper surface of the support plate and extends upwardly therefrom.

2. The manhole platform according to claim 1, wherein the clamping portion is lockable in the clamped position.

3. The manhole platform according to claim 1, wherein the support plate consists of a flat plate.

4. The manhole platform according to claim 1, wherein the safety cage includes an openable gate.

5. The manhole platform according to claim 1, wherein the safety cage includes a ladder support on an outer side.

6. The manhole platform according to claim 1, further comprising one or more attaching points attached to the upper side of the support plate.

7. The manhole platform according to claim 1, wherein the attaching portion of the clamping bracket comprises a bar or rod.

8. The manhole platform according to claim 1, further comprising one or more attaching points.

9. The manhole platform according to claim 8, wherein the attaching points are formed on an upper surface of the platform.

10. The manhole platform according to claim 1, wherein the clamping bracket is manual and is operated by moving the actuator between a first position and a second position.

11. The manhole platform according to claim 1, wherein the clamping bracket is automated and the actuator is a lever, switch, or button that acts to operate the clamping bracket.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0033] FIG. 1 shows the parts of a typical concrete manhole;

[0034] FIG. 2 shows the positioning of the concrete manhole of FIG. 1 in position in the ground;

[0035] FIG. 3 is a first isometric view of an embodiment of an embodiment of a manhole platform according to the present invention;

[0036] FIG. 4 is a second isometric view of the manhole platform of FIG. 3;

[0037] FIG. 5 is a plan view of the manhole platform of FIGS. 3 and 4; and

[0038] FIG. 6 is a side view of the manhole platform of FIGS. 3 to 5.

DETAILED DESCRIPTION OF THE INVENTION

[0039] An embodiment of a manhole platform 10 according to the present invention is shown in FIGS. 3 to 6. The manhole platform 10 comprises a support plate 11, a clamping bracket 12 extending from a lower side 14 of the support plate, an actuator 13 formed above an upper side 15 of the support plate, and a safety cage 16 formed about the upper side of the support plate. The manhole platform 10 is shown mounted on an upper slab 4 of a manhole 1 in FIGS. 3 and 4. The upper slab 4 has a square access hole 6 formed therethrough. The support plate 11 is square and is sized to completely cover the access hole 6 when the manhole platform 10 is clamped to the upper slab 4.

[0040] The safety cage 16 consists of railing extending around a periphery of the support plate 11 and is angled outwards from a lower end 17, attached to the support plate 11, and an upper side 18. A lockable gate 19 is provided in one side of the safety cage 16 to allow operators to enter and leave the safety cage. A ladder support 20 is formed at the upper side 18 of the railing adjacent to the lockable gate 19. A ladder (not shown) may be removably mounted to the ladder support when required.

[0041] The clamping bracket 12 allows the manhole platform 10 to be removably clamped to the upper slab 4. The clamping bracket 12 is shown in a clamping position in FIGS. 3 to 6. The clamping bracket comprises an attaching portion 21 and a clamping portion 22. The clamping portion 22 consists of two pivotable levers 23 that can be moved between a clamping position in which they are substantially parallel to the support plate 11 and an unclamped position in which they are at an angle to the support plate 11. The attaching portion consists of two braces 24 that are fixedly attached at a proximal end to the lower side 14 of the support plate 11 and at a distal end are pivotably attached to a pivotable lever 23 a short distance from an inner end of the pivotable lever 23. The attaching portion further comprises a rod 25 that is pivotably attached at a lower end to an inner end of each pivotable lever 23 and that extends upwards, through the support plate 11 to the actuator 13.

[0042] The clamping bracket 12 can be operated in the following manner. In the unclamped position, a length from an outer end of a first pivotable lever 23 to an outer end of the second pivotable lever 23 is less than a width of the access hole 6 of the upper slab 4. This allows the manhole platform to be positioned on the upper side of the upper slab 4 such that the support plate 11 is in contact and parallel with the upper side of the upper slab 4 and the access hole 6 is completely covered. A user can then use the actuator 13 to move the pivotable levers 23 to the clamping position shown in FIGS. 3 to 6 in which the length from an outer end of a first pivotable lever 23 to an outer end of the second pivotable lever 23 is greater than a width of the access hole 6 of the upper slab 4. This clamps the manhole platform 10 to the upper slab 4.

[0043] Moving the clamping bracket 12 from the unclamped position to the clamped position is achieved by pushing the actuator 13 downwards. This will act to provide a downward force on the inner end of the pivotable levers 23 and they will pivot about their connection with the braces 24 to rotate from the unclamped position to the clamped position.

[0044] This operation is reversed to unclamp the manhole platform 10 from the upper slab 4. Pulling the actuator 13 upwards acts to provide an upward force on the inner end of the pivotable levers 23 and they will pivot about their connection with the braces 24 to rotate from the clamped position to the unclamped position. At this point the width of the clamping bracket 12 will be less than a width of the access hole 6 and the manhole platform will be able to be lifted off the upper slab 4.

[0045] The manhole platform 10 can be lowered into, or lifting out, of position by attaching chains or ropes to the safety cage 16 at an appropriate point. The manhole platform is substantially formed of structural steel.

[0046] Unless otherwise indicated in the claims or by context, any feature of the preferred embodiment described above can be included in a manhole platform according to the present invention independent of any other feature.