FIELD OF THE INVENTION

The present invention relates to a shoring system for supporting sidewalls of a trench.

BACKGROUND OF THE INVENTION

Trench excavation is recognized by the Occupational Safety and Health Administration as being an extremely hazardous construction operation. Due to unstable soil conditions, landslide and cave-in of the trench sides can occur. These natural occurrences have been known to destroy equipment, postpone job completion and most seriously, injure or kill the workers inside the excavation. Therefore, shoring of trench faces is required by Occupational Safety and Health Administration.

Known shoring devices are constructed with panels having vertical face made of either wood or metal using various heights and width and being held together with supported steel bars. The wooden facing is not environmentally friendly and not encouraged by the industry and the use of metal-sheet facings is relatively heavy that takes time to weld and fix together in position. Sometimes heavy machinery is required for the lifting and fixing of these steel facings for the welding of the steel waling to the metal-sheet facings.

The metal struts that support the vertical facings can be heavy and fixing these elements in place is time consuming and can be risky to workers safety. Furthermore the metal struts need to be maintained and the rusty surfaces have to be cleared periodically before use.

Welding is necessary for the assembly of metal elements in the shoring system and in wet conditions in trenches, welding works have to be extra cautious on worker's safety. Under very wet condition, welding cannot be performed at all. SUMMARY OF THE INVENTION

It is an object of the present invention to provide an improved shoring system for supporting sidewalls of a trench.

According to one aspect of the present invention, there is provided a shoring system for supporting opposite sidewalls of a trench comprising a plurality of boards adapted for mounting on each sidewall; a pair of opposite walings adapted for fastening to the plurality of boards on the opposite sidewalls respectively; at least one pair of opposite brackets adapted for fastening to the opposite walings respectively; and a strut adapted to extend between each pair of opposite brackets, the strut being configured to allow the strut to act as an abutment mechanism to hold the plurality of boards against the sidewalls of the trench when the shoring system is assembled and in use, wherein the strut is made of fiberglass.

hi the preferred embodiment, each bracket, being made of fiberglass, has a support portion configured to receive and support an end of the strut. The support portion may be in the form of a recess or a protruding collar. The struts are extendible. The boards and walings are made of plastic or recycled plastic. The walings are fastened to the boards by plastic or fiberglass nails; and the brackets are fastened to the walings by plastic or fiberglass nails, hi another preferred embodiment, the opposite brackets are fixedly attached to opposite ends of the strut respectively.

According to another aspect of the present invention, there is provided a shoring system for supporting opposite sidewalls of a trench comprising a plurality of plastic boards adapted for mounting on each sidewall; a pair of opposite plastic walings adapted for fastening to the plurality of boards on the opposite sidewalls respectively; at least one pair of opposite fiberglass coupling brackets adapted for fastening to the opposite walings respectively, the coupling bracket having a first plate configured to abut against a first surface of the walings; a second plate attached to the first plate and configured to abut against a second surface of the walings adjacent to the first surface; and a fiberglass strut adapted to extend between each pair of opposite coupling brackets, the strut including an elongated tube having a first end and a second end, the first end adapted to be supported by one of the opposite brackets, a coaxial externally threaded rod having a first end and a second end, the first end adapted to be supported by the other one of the opposite brackets and the second end being receivable in the second end of the tube; and the tube having an internally threaded sleeve threadably engaged with the externally threaded rod and operatively engaged with the second end of the tube in an end-to-end relationship, whereby rotation of the sleeve adjusts and extends the length of the strut to forcibly hold the plurality of boards against the sidewalls of the trench.

According to a further aspect of the present invention, there is provided an end bracket for use in a shoring system for supporting opposite sidewalls of a trench, the shoring system having a plurality of boards mounted on each sidewall, a pair of opposite walings fastened to the plurality of boards on the opposite sidewalls respectively, and a plurality of struts extending between the pair of opposite walings, each strut having an externally threaded rod receivable within a coaxial tube and an internally threaded sleeve threadably engaged with the rod, the end bracket comprising a first plate being configured to abut against a first surface of the walings; and a collar member fixedly attached to the first plate at a central portion thereof, the collar member having a central axis which is perpendicular to said first plate, wherein the first plate and the collar member are made of fiberglass.

In a preferred embodiment, the end bracket further comprises a second plate attached to the first plate in a perpendicular relationship. The second plate is configured to abut against a second surface of the walings. The second plate is made of fiberglass.

According to yet another aspect of the present invention, there is provided a strut for use in a shoring system comprising a tube having a first end and a second end, the first end adapted to be fixedly connected to one of the opposite brackets; a coaxial externally threaded rod having a first end and a second end, the first end adapted to be fixedly connected to the other one of the opposite brackets, and the second end being receivable in the second end of the tube; and an internally threaded sleeve threadably adapted to engage with the externally threaded rod and adapted to operatively engage with the second end of the tube in an end-to-end relationship; whereby rotation of the sleeve extends the length of the strut to forcibly hold the plurality of boards against the sidewalls of the trench; and wherein the tube, the threaded rod and the sleeve are made of fiberglass with sufficient strength to support the weight bearing on the plurality of boards.

According to yet another aspect of the present invention, there is provided a shoring system for supporting opposite sidewalls of a trench comprising a plurality of boards adapted for mounting on each sidewall; a pair of opposite walings adapted for fastening to the plurality of boards on the opposite sidewalls respectively; and a strut adapted to extend between the opposite walings, the strut having a pair of end brackets fixed at opposite ends thereof respectively, the strut being configured to allow the strut to act as an abutment mechanism to hold the plurality of boards against the sidewalls of the trench when the shoring system is assembled and in use, wherein the strut and the end brackets are made of fiberglass.

The shoring system of the present invention utilizes struts made of fiberglass. Fiberglass has a strength equivalent to or greater than those of steels; but the specific gravity of fiberglass in general is of the order of one-fifth the specific gravity of steel. The use of fiberglass struts in the shoring system therefore greatly reduces the weight of the shoring system yet having sufficient strength to support the weight bearing on the shoring system. The fiberglass struts can be carried, lifted and fixed in place easily by workers in the trench. The use of non-conductive material, such as fiberglass, for the shoring system is encouraged to promote the safety of workers in trench excavation for all ground conditions and weather conditions, including wet weather condition. The entire shoring system, including fiberglass struts, can be assembled manually. No heavy machineries or welding equipments are required. Since no welding is necessary, the shoring system can be assembled in even wet weather. This will largely reduce the installation time and costs.

Furthermore, the shoring system of the present invention may utilize boards and walings made of recycled plastic. This most preferred embodiment would make the shoring system of the present invention much more environmental-friendly than conventional shoring systems utilizing wood or metal. Wood will buckle and metal will rust and will have to be discarded causing environmental issue. Therefore, recycled plastic boards and walings, according to the preferred embodiment, are more durable than wood or metal boards or walings. Also, it is safer to handle plastic boards and walings than wood or metal boards and walings which are heavy and have sharp edges. The use of non-conductive material, such as plastic, for the shoring system also promotes the safety of workers in trench excavation for all ground conditions and weather conditions, including wet weather condition. Again, plastic boards and walings can be carried, lifted and fixed in place easily by workers in the trench. The entire shoring system, including plastic boards and walings, can be assembled manually. No heavy machineries or welding equipments are required. Since no welding is necessary, the shoring system can be assembled in even wet weather. This will largely reduce the installation time and costs.

BRIEF DESCRIPTION OF THE DRAWINGS

Specific embodiments of the invention will now be described by way of example with reference to the accompanying drawings wherein:

FIG. 1 is an illustrative diagram showing a shoring system according to an embodiment of the present invention;

FIG. 2 is a perspective view of the shoring system of FIG. 1;

FIG. 3 a is a perspective view of a first coupling bracket according to an embodiment of the invention;

FIG. 3b is a perspective view of a second coupling bracket according to an embodiment of the invention;

FIG. 3 c is a perspective view of a coupling bracket according to another embodiment of the invention; FIG. 4a is a side view of the coupling bracket of FIG. 3a; FIG. 4b is a cross sectional view of the coupling bracket of FIG. 3b; FIG. 4c is a side view of the coupling bracket of FIG. 3c; FIG. 5 is a perspective view of a section of an elongated tube of a strut according to an embodiment of the present invention; FIG. 6 is a sectional view of the elongated tube; FIG. 7 is a perspective view of a section of an externally threaded rod of the strut; FIG. 7a is a perspective view of a section of an externally threaded rod of the strut according to another embodiment of the invention; FIG. 8 is a cross sectional view of the externally threaded rod of FIG 7; FIG. 8a is a cross sectional view of the externally threaded rod of FIG. 7a; FIG. 9 is a perspective view of a control knob of the strut; FIG. 10 is a sectional view of the control knob of the strut; FIG. 11 is a perspective view of a control knob of the strut according to a second embodiment of the invention; FIG. 12 is a sectional view of the control knob of FIG. 11; FIG. 13 is cutaway and fragmentary sectional view showing a first segment of the strut with an end bracket fixed at one end thereof; FIG. 14 is a cutaway view showing a second segment of the strut with an end bracket fixed at one end thereof; and

FIG. 15 is a cutaway and fragmentary sectional view showing the first and second segments and the control knob operatively coupled together.

DETAILED DESCRIPTION OF THE INVENTION

Referring now to the drawings, in which like reference numerals represent like parts throughout the drawings, FIG. 1 is an illustrative diagram showing a shoring system generally designated by reference numeral 10. The shoring system 10 is employed to support the opposite sidewalls 12 of an excavation trench 14, such as a cable trench, and prevent the sidewalls 12 of the trench 14 from collapsing.

FIG. 2 is a perspective view of the shoring system 10 in accordance with a preferred embodiment of the present invention. The shoring system 10 includes a plurality of boards 16, a pair of opposite walings 18, pairs of coupling brackets 20, 120 and a layer of struts 22.

The plurality of boards 16 and the walings 18 are preferably made of plastic and, more preferably, made of recycled plastic. This makes the shoring system 10 of the present invention an environmental friendly shoring system.

Each strut 22 comprises a tube 40, a rod 50, a control knob 70 and a pair of coupling brackets 20, 120. The tube 40, the rod 50, the control knob 70 and the pair of coupling brackets 20, 120 are preferably made of fiberglass. The advantage of using fiberglass is that it is light weighted and non-conductive.

The combined usage of plastic boards 16, plastic walings 18, and fiberglass struts 22 renders the shoring system 10 more durable and reliable. It also enhances the safety in installation. Each board 16 is placed vertically against the sidewall 12 of the trench 14. The length of each board 16 is substantially equivalent to the height of the sidewall 12 of the trench 14 such that each board 16 extends generally from the bottom of the trench 14 to the top of the sidewall 12, as best illustrated in FIG. 1. Preferably, the width of each board 16 is about 20cm and the height of each board is about 3cm.

The boards 16 are placed in a side-by-side relationship covering substantially the entire surfaces of the sidewalls 12. The boards 16 may be connected to one another by tongue and groove elements. If openings are required, sections of the boards 16 can be sawn off to make the necessary apertures.

A pair of horizontally extending walings 18 are fastened to the plurality of boards 16 on the opposite sidewalls 12 respectively at a middle portion thereof. Each waling 18 preferably has a square cross section with a dimension of about 5cm x 5cm.

Each waling 18 is attached to the plurality of boards 16 by means of hard plastic or fiberglass nails 24.

A layer of spaced apart struts 22 extend between the opposite walings 18 along the entire length thereof.

Although it has been described and shown in FIG. 1 that there is only a pair of opposite walings 18 and a layer of struts 22 extending between the walings 18, it is understood that the shoring system 10 may have two or more pairs of opposite walings 18 and two or more layers of struts 22 for deep trench excavation.

The entire shoring system 10 can be assembled manually. There is no need for heavy machineries or welding equipment.

FIGS. 3a and 4a show a first coupling bracket or end bracket 20 in accordance with a preferred embodiment of the present invention. The end bracket 20 has a first plate 30 and a second plate 32 disposed perpendicularly with respect to the first plate 30. The first and second plates 30, 32 are formed in one piece of fiberglass. The end bracket 20 is adapted to be fastened to the walings 18 by hard plastic or fiberglass nails 24 through the first plate 30, as illustrated in FIG. 1.

The second plate 32 of the end bracket 20 is provided with a strut support structure in the form of a central protruding ring or collar 36 for snugly receiving therein an end 54 of the rod 50 of the strut 22. The central protruding collar 36 has a central axis which is perpendicular to the second plate 32. The central protruding collar 36 has an outer annular surface 36a and an inner annular surface 36b. The central protruding collar 36 defines a central bore 36c therein for receiving the end 54 of the rod 50. The central protruding collar 36, being made of fiberglass, is fixedly connected to the second plate 32 on one side thereof by glue. The central protruding collar 36 is preferably in the form of a section of the tube 40.

FIGS. 3b and 4b show a second coupling bracket or end bracket 120 in accordance with a preferred embodiment of the present invention. The end bracket 120 has a first plate 30 and a second plate 32 disposed perpendicularly with respect to the first plate 30. The first and second plates 30, 32 are formed in one piece of fiberglass. The end bracket 120 is adapted to be fastened to the walings 18 by hard plastic or fiberglass nails 24 through the first plate 30, as illustrated in FIG. 1.

The second plate 32 of the end bracket 120 is provided with a central opening 35. A ring or collar 37 is adapted to be received in the central opening 35 at one end thereof such that the end of the collar 37 is substantially flush with an inner surface 33 of the second plate 32. The other end of the collar 37 forms a protruding collar portion for snugly receiving inside a bore 42 at the end 44 of the tube 40. The collar 37 has a central axis which is perpendicular to the second plate 32. The collar 37 has an outer annular surface 37a and an inner annular surface 37b. The collar 37 is fixedly connected to the second plate 32 in the central opening 35 by glue.

FIGS. 3c and 4c show a coupling bracket or end bracket 220 in accordance with another embodiment of the present invention. The end bracket 220 has a first plate 30 and a second plate 32 disposed perpendicularly with respect to the first plate 30. The first and second plates 30, 32 are formed in one piece of fiberglass. The second plate 32 of the end bracket 220 is provided with a strut support structure in the form of a central recess 34 for snugly receiving therein the end 54 of the rod 50 or the end 44 of the tube 40.

FIG. 5 shows a section of the elongated tube 40 of the strut 22 according to an embodiment of the present invention. The elongated tube 40 defines an elongated bore 42 therein. The elongated tube has a bracket-engaging end 44 and a rod- engaging end 46. The bracket-engaging end 44 is adapted to couple with the collar 37 of the coupling bracket 120, as shown in FIG. 13.

The tube 40 is made of fiberglass and has a length of preferably about 100cm.

FIG. 6 is a cross sectional view of the elongated tube 40 of the strut 22. The outer diameter of the tube 40 is preferably about 3.5cm and the inner diameter of the tube 40 is preferably about 2.5cm.

FIG. 7 shows a section of the bar or rod 50 of the strut 22 according to an embodiment of the invention. The rod 50 is in the form of a solid fiberglass rod. External threads 58 are provided on the outer surface of the rod 50 along the entire length thereof. The external threads 58 on the rod 50 may be continuous or intermittent. The fiberglass rod 50 can be easily cut on site to any length, as desired. This allows each fiberglass rod 50 to be specifically made according to its location and can accommodate changes easily to suit actual site conditions and measurements in a very cost effective manner. There is no corrosion problem as in the convention steel soil nail system.

The externally threaded rod 50 has a bracket-engaging end 54 and a tube-engaging end 56. The bracket-engaging end 54 is adapted to be received in and supported by the collar 36 of the end bracket 20, as shown in FIG. 14. The length of the rod 50 is preferably about 100cm.

FIG. 7a shows a section of the bar or rod 50' according to another embodiment of the invention. The rod 50' is the same as rod 50 of FIG. 7 except that the rod 50' is hollow and has a longitudinal bore 51. External threads 58 are provided on the outer surface of the rod 50' along the entire length thereof. The external threads 58 on the rod 50' may be continuous or intermittent. The externally threaded rod 50' has a bracket-engaging end 54 and a tube-engaging end 56. The bracket-engaging end 54 is adapted to be received in and supported by the collar 36 of the end bracket 20, as shown in FIG. 14.

FIG. 8 is a cross sectional view of the externally threaded rod 50. The outmost diameter of the externally threaded rod 50, preferably of 2.3cm, is slightly less than the inner diameter of the elongated tube 40 such that the externally threaded rod 50 can be slidably received in the elongated bore 42 of the elongated rod 40.

FIG. 8a is a cross sectional view of the externally threaded rod 50' having a longitudinal bore 51.

FIG. 9 is a control knob 60 of the strut 22 according to a first embodiment of the invention. The control knob 60 is in the form of a sleeve or collar having internal threads 62. The internal threads 62 are adapted to threadably engage with the external threads 58 of the rod 50.

FIG. 10 is a cross sectional view of the control knob 60 of FIG. 9.

FIG. 11 is a control knob 70 of the strut 22 according to a second embodiment of the invention. The control knob 70 is in the form of a sleeve or collar having internal threads 72. The internal threads 72 are adapted to threadably engage with the external threads 58 of the rod 50. The control knob 70 has an outer surface having a hexagonal cross section to facilitate gripping and turning of the control knob 70 by a user.

FIG. 12 is a cross sectional view of the control knob 70 of FIG. 11.

When the shoring system 10 is assembled, the tube-engaging end 56 of the externally threaded rod 50 is received in the rod-engaging end 46 of the elongated tube 40. The internally threaded control knob 60, 70 is threadably engaged with the externally threaded rod 50 at the tube-engaging end 56 thereof. The control knob 60, 70 is in an end-to-end relationship with the elongated tube 40. By way of such an arrangement, the length of the strut 22 can be adjusted by turning the control knob 60, 70 in either the clockwise or anti-clockwise direction.

The strut 22 is supported by and extending between each pair of opposite brackets 20, 120. By turning the control knob 60, 70 in one direction, the length of the strut 22 can be extended allowing the strut to act as an abutment mechanism to forcibly press the plurality of boards 16 against the two opposite sidewalls 12 of the trench 14. The tube 40, the rod 50, the control knob 60, 70, and the brackets 20, 120 are made of fiberglass with sufficient strength to support the weight bearing on the boards 16.

hi addition, a lock (not shown) may be coupled with the control knob for locking the rod 50 in a fixed position relative to the tube 40.

Although it has been shown and described that the strut 22 and the brackets 20, 120 are separate members, it is appreciated that the brackets 20, 120 can be fixedly connected to the strut 22 as described hereinbelow.

FIGS. 13-15 show a strut 22 comprises a first strut segment 22a and a second strut segment 22b. The end 44 of the tube 40 is fixedly connected to the end bracket 120 to form the first strut segment 22a. The end 54 of the rod 50 is fixedly connected to the end bracket 20 to form the second strut segment 122b.

FIG. 13 is cutaway and fragmentary sectional view of the first strut segment 22a. The first strut segment 22a comprises an elongated tube 40 and an end bracket 120 fixedly connected to one end thereof. The elongated tube 40 defines an elongated bore 42 therein. The elongated tube 40 has a bracket-engaging end 44. The collar 37 of the end bracket 120 is adapted to be snugly fitted within the bore 42 at the bracket- engaging end 44 of the tube 40. Glue is applied to the joining area of the end bracket 120 and the tube 40 to fixedly connect the end bracket 120 to the tube 40. FIG. 14 is a cutaway view showing the second strut segment 22b. The second strut segment 22b comprises an externally threaded rod 50, 51 and an end bracket 20 fixedly connected to one end thereof. The rod 50, 51 may be solid or hollow, as shown in FIGS. 7 and 7a. The externally threaded rod 50, 51 has a bracket-engaging end 54. The bracket-engaging end 54 of the rod 50, 51 is adapted to be snugly fitted within the collar 36 of the end bracket 20. Glue is applied to the joining area of the end bracket 20 and the rod 50, 51 to fixedly connect the end bracket 20 to the rod 50, 51.

FIG. 15 is a cutaway and fragmentary sectional view showing the first and second segments 22a, 22b and the control knob 70 operatively coupled together forming the strut 22 of the present invention.

When the shoring system 10 is assembled, the tube-engaging end 56 of the second strut segment 22b is received in the rod-engaging end 46 of the of the first strut segment 22a. The internally threaded control knob 70 is threadably engaged with the externally threaded rod 50, 51 at the tube-engaging end 56 thereof. The control knob 70 is in an end-to-end relationship with the elongated tube 40. The end brackets 20, 120 are fastened to respective opposite walings 18 by plastic or fiberglass nails 24. By turning the control knob 70, the length of the strut 22 can be extended allowing the strut to act as an abutment mechanism to forcibly press the plurality of boards 16 against the two opposite sidewalls 12 of the trench 14.

While the present invention has been shown and described with particular references to a number of preferred embodiments thereof, it should be noted that various other changes or modifications may be made without departing from the scope of the present invention.