Title:
TRENCH DEVICE AND METHOD
Kind Code:
A1


Abstract:
A catwalk is provided for use in trenching operations that provides increased safety and improves efficiency. Methods are also provided that save time over the prior process of building multiple land bridges. Selected features include reduction in the number of ladders used increases worker safety, along with several other safety features such as catwalk railings, holding devices for ladders, etc. One catwalk is shown with a skid assembly to further increases efficiency by allowing the trench box to be towed with the catwalk in place. A manhole catwalk is shown for easy and safe inspection of manholes without the need for ladders.



Inventors:
Raspotnik, John (Ashland, WI, US)
Application Number:
11/627244
Publication Date:
05/15/2008
Filing Date:
01/25/2007
Primary Class:
International Classes:
E04G3/32
View Patent Images:
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Primary Examiner:
CHIN-SHUE, ALVIN CONSTANTINE
Attorney, Agent or Firm:
SCHWEGMAN LUNDBERG & WOESSNER, P.A. (MINNEAPOLIS, MN, US)
Claims:
I claim:

1. A catwalk assembly, comprising: a floor having an opening sized to fit over a top portion of a manhole, wherein the opening is further sized to slide only a portion of the way down the manhole; a first end of a catwalk for placement on an edge of a trench; and a second end of the catwalk for connection to the floor.

2. The catwalk assembly of claim 1, further including guard rails substantially around the floor and the catwalk.

3. The catwalk assembly of claim 1, wherein the catwalk includes a number of jointed sections.

4. The catwalk assembly of claim 1, further including at least one spacer to attach within the opening, the spacer changing a width of the opening along at least one dimension.

Description:

PRIORITY APPLICATIONS

This patent application claims the benefit of priority, under 35 U.S.C. Section 119(e), to U.S. Provisional Patent Application Ser. No. 60/743,171, filed on Jan. 25, 2006, which is incorporated herein by reference.

TECHNICAL FIELD

This invention relates to walkways that allow access from one location to another. Specifically, this invention relates to catwalks from an edge of a trench to items within the trench.

BACKGROUND

FIG. 1 shows a common trench 100. Trenches are used for a variety of purposes such as utility installation. Some examples of utilities include, but are not limited to, sanitary sewer, storm sewer, water supply, gas, electric, etc. A trench box 110 is commonly used when constructing trenches 100 to keep the sides of the trench 100 from caving in during construction.

During construction, workers must move in and out of the trench 100. Currently, workers construct a land bridge 120 from dirt and lower a first ladder 130 to the land bridge 120. A worker must go down the first ladder 130 to the land bridge 120 in order to cross from the edge 102 of the trench 100 to an edge 112 of the trench box 110. Then the worker must use a second ladder (not shown) to get from the edge 112, into the trench box 110. As digging of the trench 100 progresses, the trench box 110 must be moved, and a new land bridge 120 must be constructed for each move of the trench box 110.

In some trenching operations, manholes are installed within the trench. Inspection of manholes is currently difficult. Ladders are currently used to get from the bottom of the trench up to the manhole opening. The ladder rungs and/or the top of the manhole are not protected with any safety rails and the inspector is left in an unstable position.

What is needed is an improved device and method to increase efficiency and safety during trenching operations.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 shows a trench box and trench according to the prior art.

FIG. 2 shows a configuration of a catwalk according to an embodiment of the invention.

FIG. 3 shows another configuration of a catwalk according to an embodiment of the invention.

FIG. 4 shows an end view of a catwalk according to an embodiment of the invention.

FIG. 5 shows a detail view of a catwalk according to an embodiment of the invention.

FIG. 6 shows another detail view of a catwalk according to an embodiment of the invention.

FIG. 7 shows a manhole in a trench with a catwalk assembly according to an embodiment of the invention.

FIG. 8 shows a top view of a portion of the catwalk assembly from FIG. 7.

DETAILED DESCRIPTION

In the following detailed description, reference is made to the accompanying drawings which form a part hereof, and in which is shown, by way of illustration, specific embodiments in which the invention may be practiced. In the drawings, like numerals describe substantially similar components throughout the several views. These embodiments are described in sufficient detail to enable those skilled in the art to practice the invention. Other embodiments may be utilized and structural, or logical changes, etc. may be made without departing from the scope of the present invention.

FIG. 2 shows a catwalk 200 that bridges a gap between an edge 102 of a trench 100 and an edge 112 of a trench box 110. In one embodiment, the catwalk 200 includes multiple sections. In one embodiment, the multiple sections are hinged together to accommodate multiple possible trench configurations. FIG. 2 shows a first section 202 and a second section 204 with a hinge joint 203 between them. A third section 206 is further shown with a hinge 205 between the second section 204 and the third section 206. In one embodiment, each section of the catwalk 200 includes hand rails. In one embodiment, the catwalk is fabricated from welded steel, although the invention is not so limited. Other configurations include alternate materials such as aluminum, wood, polymers, etc. Other fabrication techniques, apart from welding, include fasteners such as screws, adhesive assembly, pressure fits, etc. Although three sections are shown in FIG. 2, other configurations include fewer sections, or more sections depending on factors such as the trench configuration, the job site, etc.

A ladder 210 is shown in FIG. 2 to enter the trench box 110 from the catwalk 200. It should be noted that with the configuration shown in FIG. 2, only one ladder is needed to enter the trench box 110. A digger such as a backhoe 220 is further shown for digging the trench 100. In one embodiment, the backhoe 220 is further used to pull the trench box 110 back as the trench progresses.

FIG. 3 shows the catwalk 200 in position along a trench 100 with a different profile from FIG. 1. The catwalk 200 in FIG. 2 shows the pivot 203 rotated to where the first section 202 and the second section 204 but up against each other, creating a continuous flat walking surface between then first section 202 and the second section 204.

FIG. 4 shows a portion of the first section 202 located on the edge of the trench. In one embodiment, a skid assembly 400 is included in the catwalk 200. In one embodiment, the skid assembly 400 includes a sliding portion 402 and a hinge 404. In one method of operation, the skid assembly 400 allows the catwalk to slide along the edge of the trench as the trench box is pulled. As discussed above, in one embodiment, the trench box is pulled along by a digging device such as a backhoe as digging of the trench progresses. One advantage of a skid assembly includes efficiency and speed of a trenching operation. In contrast to the configuration described in FIG. 1, after moving the trench box, there is no need to construct a new land bridge for entry and exit from the trench box.

FIG. 5 shows the third section 206 of the catwalk 200 in closer detail as it is attached to the trench box 110. In one embodiment, a fitting 207 such as a pair of metal protrusions line up with a side of the trench box 110. The fitting 207 holds the end of the catwalk onto the trench box 110 for safety, and to keep the catwalk from falling off the trench box 110 during a moving operation as the trench progresses. In one embodiment, the fitting 207 includes a mating feature welded to the trench box 110 where the catwalk 200 includes an engaging feature that is adapted to mate with the mating feature on the trench box. In one embodiment, the mating feature includes at least one section of a metal cylinder that can be pinned to the catwalk.

The hinge between the second section 204 and the third section 206 has an added advantage in that the first and second sections 202, 204 can be folded up on top of the third section 206 for selected moving of the trench box 110. In one method, an obstacle such as a tree or power pole prevents the catwalk from remaining extended during a move of the trench box 110. In such a situation, multiple sections of the catwalk can be folded up until the obstacle is passed.

FIG. 6 shows a detail of a portion of the third section 206 of the catwalk 200. In one embodiment, a holding device 209 such as a hook, clamp, etc. is included on the catwalk 200. The holding device 209 can be used to hold a ladder 210. One advantage of the holding device 209 includes safety to prevent the ladder 210 from falling into the trench box. Another advantage of the holding device includes the ability to store items such as a ladder 210 or a shovel during a moving operation of the trench box. Although one holding device 209 is shown in FIG. 6, multiple holding devices are included in other embodiments, for example to hold both a shovel and a ladder.

FIG. 7 shows a catwalk assembly 700 for use with a manhole. A manhole 720 is shown inside a trench 710. A manhole unit 730 is shown to facilitate easy and safe inspection of the manhole 720. In one embodiment, the manhole unit 730 can be used with catwalk sections as described above. The manhole unit 730 includes a floor 732. The floor 732 includes an opening 734. As shown in the figure, manholes frequently include a taper to their structure. In one embodiment, the opening 724 in the floor 732 is sized and shaped to pass over a top of the manhole 720, and stop when it encounters the tapered portion. A square opening 734 is shown in FIG. 7, however the invention is not so limited. In one embodiment, a circle opening 734 is used. Other geometries such as triangles, etc. are also possible. In one embodiment, a square opening includes approximately a 36 inch by 36 inch square to fit over a manhole with a slightly smaller diameter.

A network of guard rails 736 is shown around a perimeter of the floor 732. The guard rails increase the safety of an inspector or other worker. A pair of catwalk sections are further shown in FIG. 7. A first catwalk section 740 is connected to the manhole unit 730. A second catwalk section 742 is coupled to the first catwalk section 740. Connection methods include those described above, such as hinged connections using bolts, nuts, pins, etc. Using the catwalk assembly 700 an inspector can easily pass from an edge of the trench 712 to the manhole 720 and inspect the manhole while maintaining good footing on the floor 732, and having the benefit of guard rails 736.

FIG. 8 shows a top view of the floor 732 from FIG. 7. The opening 734 is shown within the floor 732. In one embodiment, as shown, the opening is centered in the floor to allow a user to walk all the way around a manhole during a procedure such as an inspection.

In one embodiment, a first spacer 810 and a second spacer 820 are included. In one embodiment, the first spacer 810 and/or the second spacer 820 are optionally removable. The first spacer 810 is connected to the floor 732 on ends 812 and 814. The second spacer 820 is connected to the floor 732 on ends 822 and 824. Removable connection structures include nuts and bolts, etc.

In one embodiment, the first spacer 810 and/or the second spacer 820 are used to selectively narrow or widen the opening 734. As can be seen from FIG. 7, manholes are typically round and include a tapered portion near their top. By inserting or removing spacers within the opening 734, the original width 832 is reduced to a new width 830. In this way, if a particular manhole has a different taper, or if the height of the manhole unit 730 needs adjusting, a number of spacers can be inserted or removed until the manhole unit comes to rest in the desired position on the manhole. Although a pair of spacers are shown in FIG. 8, the invention is not so limited. In one embodiment, a single spacer is used. In one embodiment, three or more spacers are used.

CONCLUSION

Thus has been shown, a catwalk for use in trenching operations that provides increased safety and improves efficiency. The use of a catwalk saves time over the prior process of building multiple land bridges. A reduction in the number of ladders used increases worker safety, along with several other safety features such as catwalk railings, holding devices for ladders, etc. The use of a skid assembly further increases efficiency by allowing the trench box to be towed with the catwalk in place. An optional manhole attachment further adds to the versatility of the catwalk during normal trenching operations.

While a number of advantages of embodiments described herein are listed above, the list is not exhaustive. Other advantages of embodiments described above will be apparent to one of ordinary skill in the art, having read the present disclosure. Although specific embodiments have been illustrated and described herein, it will be appreciated by those of ordinary skill in the art that any arrangement which is calculated to achieve the same purpose may be substituted for the specific embodiment shown. This application is intended to cover any adaptations or variations of the present invention. It is to be understood that the above description is intended to be illustrative, and not restrictive. Combinations of the above embodiments, and other embodiments will be apparent to those of skill in the art upon reviewing the above description. The scope of the invention includes any other applications in which the above structures and fabrication methods are used.