Patent Application
20090123227
The present application relates to manhole cover assemblies, and, more particularly, to a manhole cover with dual lifting ports.
Manholes are well-known and widely utilized. Generally, a manhole provides access for maintenance of infrastructure, for instance, underground pipelines or cabling. Traditional manhole covers rest on a frame that is attached to the substructure above infrastructure to be maintained. Examples of such substructure include the base for a road or sidewalk. The cover rests on this frame and must be lifted away to gain access to the infrastructure beneath the manhole. Because manhole covers are predominantly made of iron and can weigh in excess of 100 pounds, the effort required to lift a manhole cover can be difficult and even injurious to the operator.
Many attempts have been made to ease the effort required to lift a manhole cover from its frame. For example, some manhole covers include a hole extending through the cover. To lift the cover, an operator inserts a pointed tool through the hole to either pry up or lift the cover. This method provides some additional lifting leverage, but the hole in the cover provides direct access for external contaminants to drain below to the infrastructure.
Other manhole covers include a lifting insert within the upper face of the cover. These lifting inserts are typically cast inserts that are placed in a recess in the face of the cover. The inserts define a cutout in the face of the cover, and they include a bar that extends over the cutout such that a pointed tool could be wedged underneath or against the bar to provide lifting leverage. The cutout is typically symmetrical in shape, and it typically does not extend completely through the insert to prevent external contaminants from draining through the cover. To open such a cover, an operator wedges a tool into the cutout and underneath or against the bar, and applies a force on the bar, lifting the cover away from the frame. This type of cover prevents outside contaminants from draining directly into the infrastructure, but new problems arise due to runoff and other debris that tend to collect in the cutout. Thus, an operator may be required to clear out the cutout prior to opening the cover. In addition, installing an insert in this way may generate increased manufacturing costs because of the additional steps necessary to fabricate such a cover.
The aforementioned problems are overcome by the present invention wherein a one-piece, unitary manhole cover is provided with a channel that defines a cutout in the upper face of the cover and that extends through the outer edge of the cover. A lifting bar bridges the channel and forms two separate openings in the upper face of the cover. The channel and the lifting bar are configured to form dual lifting ports, one on each side of the lifting bar, that enable easy removal of the cover by prying or lifting.
In one embodiment, a first end of the lifting channel and a first sidewall of the lifting bar cooperate to define an ergo lifting port that receives a lifting tool. The second end of the channel and a second sidewall of the lifting bar cooperate to define a pry bar lifting port. The pry bar lifting port may be located at the outer end of the channel, and may extend through the outer circumferential edge of the cover. In one embodiment, the ergo lifting port includes an arc-shaped portion of the lifting channel floor, and a lobe extending downwardly from the lower surface of the lifting bar. The portion of the floor and the lobe cooperate to receive and provide leverage for a lifting tool. In one embodiment, the pry bar lifting port includes a generally planar portion of the lifting channel floor and a generally planar portion of the lower surface of the lifting bar. The generally planar surfaces cooperate to receive and provide leverage for a pry tool.
The present invention provides a one-piece manhole cover that facilitates removal of the cover using either a specially designed lifting tool or a conventional, widely accessible pry bar lifting tool, allowing the operator to easily and efficiently open the cover. The floor of the channel prevents contaminants such as dirt and garbage from draining into the infrastructure below the manhole. Further, by extending through the outer circumferential edge of the cover, the channel allows contaminants to drain out of the channel through the outer edge of the cover.
These and other objects, advantages, and features of the invention will be readily understood and appreciated by reference to the detailed description of the current embodiment and the drawings.
A manhole cover in accordance with one embodiment of the present invention is illustrated in the drawings and designated 10. In illustrated embodiment, the cover 10 has a lower face 12, an upper face 14, an outer circumferential edge 16 and at least one channel 18 defined in the upper face and extending to the outer circumferential edge 16. In one embodiment, the channel 18 is divided by a lifting bar 24 to define an ergo lifting port 20 and a pry bar lifting port 22. In operation, as illustrated in
In the illustrated embodiment, the cover 10 is a cast iron cover of an overall disc-shaped geometry. In other embodiments, the cover 10 could be of another geometry, and another material. In one embodiment, the entire cover 10 is formed from the same material, such that the material forming the channel 18 and lifting ports 20 and 22 is unitary with the material of the surrounding areas of the cover 10. In one embodiment, the channel 18, lifting bar 24 and lifting ports 20, 22 may be fabricated using a core within the overall cover mold. Suitable alternative materials and fabrication methods may also be utilized.
As noted above, the cover 10 has a lower face 12 and an upper face 14, and an outer circumferential edge 16. The cover defines a thickness 21 between the upper face 14 and lower face 12. In one embodiment, the upper face 14 may include projections and designs that indicate the owner of the cover 10, the manufacturer, the type of infrastructure beneath the manhole or any other pattern. The lower face 12 may include a downwardly extending projection 33 extending around the cover 10 proximate the outer circumferential edge 16, such that the thickness 21 of the cover increases proximate the outer circumferential edge 16.
The cover 10 is adaptable to be received by many different frame configurations. In the embodiment illustrated in the figures, the lower face 12 of the cover 10 rests on a cover support rim 28 of a frame 26. The frame 26 may include a frame wall 30 rising away from the substructure the frame 26 is mounted on. The frame wall 30 is an annular ring defining an inner surface 32. The cover support rim 28 projects from the inner surface 32 of the frame wall 30. An upper segment 34 of the frame wall 30 may extend beyond the cover support rim 28. The upper edge 31 of the upper segment 34 may be flush with the upper surface 14 of the cover when the cover 10 is in place on the cover support rim 28. The inside diameter of the frame wall 30 is slightly greater than the diameter of the cover 10 to provide clearance between the upper segment 34 of the frame wall 30 and the outer circumferential edge 16 of the cover 10 when the cover is installed on the frame 26. In another embodiment, the lower face of the cover could rest directly on the annular top of the frame wall.
In the illustrated embodiment, the cover 10 includes at least one channel 18 that defines openings in the upper face 14 for the ergo lifting port 20 and the pry bar port 22. The channel extends through the outer circumferential edge 16 toward the center of the cover 10. In one embodiment, two channels 18 are disposed on opposite sides of the cover 10. In other embodiments, one or more channels could be arranged in any configuration around the edge. The illustrated channel 18 includes a lifting bar 24 that extends across the width of the channel 18 and divides the channel 18 into the ergo lifting port 20 and the pry bar port 22. The illustrated channel 18 extends from the outer circumferential edge to an interior end 39 in the interior of the cover 10.
The channel includes a floor 52 that may be configured to receive an ergo lifting tool 60 through the ergo lifting port 20 and a pry tool 70 through the pry bar lifting port 22. In one embodiment, the floor 52 includes an ergo lifting arc 54, a pick leverage face 56 and a pry bar port lead in surface 58. In the embodiment illustrated in the figures, the ergo lifting arc 54 is a smooth, arcing surface extending from the upper face 14 of the cover 10 to the pick leverage face 56. A portion of the ergo lifting arc 54 extends below the pick leverage face 56. The pick leverage face 56 is a generally flat surface that connects the ergo lifting arc 54 to the pry bar port lead in surface 58. The plane of the illustrated pick leverage face 56 is parallel to the overall plane of the cover 10. The pry bar port lead in surface 58 extends from the pick leverage face 56 to the outer circumferential edge 16 of the cover 10. In the embodiment illustrated in the figures, the pry bar port lead in surface 58 is a ramped surface that slopes toward the upper face 14 of the cover 10 as the lead in surface 58 moves toward the outer circumferential edge 16 of the cover 10. The outer edge 61 of the pry bar port lead in surface is below the upper face 14 of the cover to define an opening in the outer circumferential edge 16 that allows the contents of the channel 18 drain over the pry bar port lead in surface 58 and through the outer circumferential edge 16.
As illustrated, the lifting bar 24 bridges the channel 18 and is spaced from the channel floor 52 to form the ceiling of the channel 18. The upper surface 42 of the lifting bar 24 may be flush with the upper face 14 of the cover 10. In one embodiment, an ergo lifting lobe 46 projects into the channel 18 from the lower surface 40 of the lifting bar 24. A first sidewall 48 of the lifting bar 24 may form a portion of the lifting lobe 46 and may transition in a rounded curve to the lower surface 40 of the lifting bar 24. A second sidewall 50 may also transition via a slightly rounded curve into the generally flat portion of the lower surface 40.
The interior end 39 of the channel 18 and the lifting bar 24 cooperate to define the ergo lifting port 20. In the illustrated embodiment, the ergo lifting port 20 is of an overall rectangular shape but the ergo lifting port 20 could be of alternate geometries to receive lifting tools 60 of various configurations. The ergo lifting port 20 is configured to receive a hook-shaped a lifting tool 60. As shown in
In operation, the point 64 of the tool 60 is inserted through the ergo lifting port 20, into the channel 18 and under the lifting bar 24. The arc shaped portion 54 of the channel 18 allows the tool 60 to enter the channel 18 with the lower face 68 of the tool 60 pressed against the pick leverage face 56, and the upper face 66 of the tool 60 pressed against the ergo lifting lobe 46. The operator applies a lifting force to the handle 62 of the tool 60, and leveraging forces are applied to the pick leverage face 56 and the ergo lifting lobe 46 allowing the operator to lift the cover 10 up and away from the frame 26, as can be seen in
In one embodiment, the pry bar lifting port 22 is a bi-planar aperture formed at the outer end 61 of the channel 18 where the outer circumferential edge 16 and upper face 14 of the cover 10 meet. Although the hook-shaped lifting tool 60 could be used in the pry bar lifting port to pry open the cover 10, various prying tools 70 are well-known in the art and more suitable for use with the pry bar port 22 of cover 10. One such prying tool is illustrated in
In alternative embodiments, the ergo lifting port and pry bar lifting port may be alternatively sized or shaped to accept different styles of tools. In other embodiments, the lifting channel could be alternatively configured as well, based on the tool to be used. One or more of the ergo lifting arc, pick leverage face, pry bar port lead in surface, rounded corners and lifting lobe could be eliminated or altered to accommodate alternate tool styles.
The above description is that of the current embodiment of the invention. Various alterations and changes can be made without departing from the spirit and broader aspects of the invention as defined in the appended claims, which are to be interpreted in accordance with the principles of patent law including the doctrine of equivalents. Any reference to claim elements in the singular, for example, using the articles “a,” “an,” “the” or “said,” is not to be construed as limiting the element to the singular.
