AU2021103538A4 - Safety Grate with Anti-Withdrawal Device - Google Patents

Abstract

A safety grate system including at least one anti-withdrawal device to secure the grate to a manhole cover to improve worker safety in environments where access through the manhole is required. 11 1 of 7 100 107 FIGUREl1A SAFETY GRATE PURPOSELY DESIGNED PERFORATIONS, SEE THROUGH, AND VENT OLES OF ANY SHAPE OR FORM 102 PURPOSELY BUILTATTACHMENT, SEE THROUGH, SLOTS AND VENT 104 100 PURPOSELY BUILT ATTACHMENT, SEE THROUGH, AND VENT HOLESOFANYSHAPEFORFORM FIGURElB

Description

1 of 7

100

107

FIGUREl1A

SAFETY GRATE PURPOSELY DESIGNED PERFORATIONS, SEETHROUGH, AND VENT OLES OF ANY SHAPE OR FORM

102

PURPOSELY BUILTATTACHMENT, SEE THROUGH, SLOTS AND VENT

104

100

PURPOSELY BUILT ATTACHMENT, SEE THROUGH, ANDVENT HOLESOFANYSHAPEFORFORM

FIGURElB

SAFETY GRATE WITH ANTI-WITHDRAWAL DEVICE

Technical Field The present invention relates to an improved safety grate with anti-withdrawal features, particularly for use of a camera and the like during maintenance.

Background It is widely known in the industry that opening a manhole is a high risk and activity that requires operators to erect approved safety equipment in order to adhere to current legislation. It is impractical and inefficient to erect and remove, in typical situations, safety barricades each time a manhole is needed to be inspected or maintenance to be carried out.

Manhole covers are heavy, typically circular, plates used to close vertical shafts, i.e. manholes. Manholes provide access to underground areas such as water and storm water pipes, sewage ways and other underground utility areas.

The following is a non-comprehensive list of the procedure to be administered during typical manhole maintenances.

Procedure Prior to Removal of Manhole Cover: Erect safety barricades for a safe working perimeter; Set up your working equipment around perimeter such as cranes, tripods and certified anchor points; Have all operators to be anchored to a certified anchor point; and Use lever to remove the manhole cover.

Procedure Post Inspection or Maintenance: Replace manhole cover; Remove equipment and detach from certified anchor points; and Remove safety barricade.

However, a problem exists in present design of safety grills. Current grates are heavy to carry and cumbersome to handle. Furthermore, current design of the manhole covers does not facilitate safe use of accessories such as cameras and hoses during work conducted by workers below ground level. Consequently, it will be realized that the present invention will be a useful alternative to the costly and inefficient current safety grates in the inspection and maintenance of manhole operations as detailed below.

Summary of the Invention When operating around manholes and sewerage openings, barricades are erected to form a barrier so that no outside influences can affect the working environment. All workers below and above ground are to be harnessed to a certified anchor point at all times to prevent falls from heights into the confined space.

Furthermore, the grates are heavy to carry and load for transportation. Additionally, attachments and other peripheral equipment are required to perform tasks below ground. Moreover, there is no means to accommodate convenient and safe use of accessories such as cameras and hoses during work conducted by workers below ground level.

A temporary safety manhole cover may be used whenever the common manhole cover is removed or any other water related opening. It is designed to eliminate the need of the existing maintenance procedure of setting up the manhole and being harnessed and anchored to a certified anchor point whilst works are carried out near or over openings. With this innovation, only the operator who is conducting maintenance below ground needs to be secured using a harness hooked up to a winch, which is secured to a certified anchor point situated above ground.

Furthermore, the design of the grate according to the present invention allows folding of the grate and provision to attach additional members such as rollers to accommodate cables and the like.

Advantages of the Invention: facilitates use of accessories such as cameras and hoses; bends and folds in half for ease of carry and transportation; decreases risk of injury to both workers below and at top of ground; eliminating the risk of falling from heights; reducing the set up time of the maintenance and/or inspection procedures; the grate weighs less than existing manhole covers and can easily be removed and put back in place by a single road worker; corrosion resistant; and cost effective to the cost and maintenance of existing fall from heights safety equipment and certified anchor points. The cover is versatile and can be made to any shape to suit any application; and the manhole cover is typically circular in shape but manhole openings of other shapes including but not limited to rectangular and oval configurations.

In another aspect, a safety grate is disclosed that includes a manhole cover body adapted to overlie a standard manhole; and at least one anti-withdrawal device configured to secure the cover to the manhole. The anti-withdrawal device may include opposed clamping surfaces to clamp the cover to the manhole. The anti withdrawal device may be longitudinally adjustable to accommodate a variation of manhole surface thicknesses. The anti-withdrawal device may be a fixing configured to be inserted generally parallel to a horizontal plane of the cover. The anti-withdrawal device may be a screw. It will be appreciated that not every manhole cover need include an antiwithdrawal device, depending upon the intended use.

The disclosure of U.S. Patent No.10,508,405 to Harazim is incorporated herein by reference.

Brief Description of the Figures Figs. 1A and B show a safety grate in accordance with a preferred embodiment of the present description.

Figs. 2A, 2B, 2C, 2D, and 2E each show a cross sectional side view of the grate of Fig. 1 with a hose and attachments inserted therethrough.

Fig. 3 is a perspective view of the grate and attachment of Fig. 2.

Fig. 3A is an expanded view of an interchangeable attachment inserted through the grate of Fig. 3.

Fig. 4 is a perspective view of the grate of Fig. 1 overlying a manhole.

Fig. 5 is a perspective view of the grate of Fig. 4 overlying a manhole, with two anti-withdrawal devices connected to the grate.

Fig. 5A is a cross sectional side view of the grate of Fig. 5 with the anti-withdrawal devices in an unengaged position.

Fig. 5B is a cross sectional side view of the grate of Fig. 5A with the anti withdrawal devices in an engaged position.

Fig. 6A is a perspective view of the anti-withdraw device of Fig. 5A.

Fig. 6B is a left side elevation view of the anti-withdraw device of Fig. 6A.

Fig. 6C is a top plan view of the anti-withdraw device of Fig. 6A.

Fig. 6D is a right side elevation view of the anti-withdraw device of Fig. 6A.

Fig. 7 is a partial top cross sectional view of the grate of Fig. 1 with a plurality of fixings to secure the grate to the manhole in accordance with another preferred embodiment.

Fig. 8 is an enlarged partial top cross sectional view of the grate of Fig. 7.

Fig. 8A is an enlarged view of Fig. 7 showing the fixing engaging the cover to the manhole.

Fig. 8B is a side cross sectional view of the grate of Fig. 8.

Fig. 8C is an enlarged side cross sectional view of Fig. 8B.

Figs. 9A to B are partial cross sectional side views of a jetting withdraw procedure in accordance with an embodiment of the description.

Detailed Description of the Drawings Reference will now be made in detail to the present preferred embodiments of the disclosure, examples of which are illustrated in the accompanying drawings.

Figs. 1 to 3 show a grate or cover 100 configured to overly a manhole 10. Referring to Figs. 1A and 1b, grate 100 includes a pair of opposed vents 102, and a plurality of attachment slots 104.

Figs. 2A, 2D, and 2E show a hose 106 inserted through a main aperture 107 (Fig. 1A). The hose may have one or more cleaning implement 120 connected to it, such as a SG-Clean device. Fig. 2B shows an anti-withdraw device 210 in the form of a screw, the details of which are described further below in relation to Figs. 7 and 8. Fig. 2C shows an anti-withdrawal device 110 in the form of an adjustable clamping arm, the details of which are described further below in relation to Figs. 5 and 6.

Referring to Fig. 4, cover 100 is shown positioned over a manhole 10. Referring to Figs. 5A 5B shown cover 100 with a pair of anti-withdrawal arms 110 inserted therethrough to facilitate clamping cover 100 to manhole 10. Figs. 6A to 6D show anti-withdrawal arm 110 including a bottom clamping surface 112 having an anti slip surface 114, a long rotational beam or screw 116, and a top clamping surface 118.

Figs. 7 and 8 depict an anti-withdrawal device 210 for use with the cover in accordance with another embodiment of the description. Anti-withdrawal device 210 may be in the form of a screw or bolt, or other fixing that can be pressed-fit into a manhole wall to restrain the cover to the manhole.

Fig. 9A shows a jetting head 20 being lowered into the manhole. Fig. 9B shows jetting head 20 facing up towards the manhole cover. Fig. 9C shows jetting head 20 accelerating upwards and impacting the cover while anti-withdrawal devices 110 retrain cover 100 in place.

The improved safety grate is a lightweight temporary safety manhole cover with a hinged access door made with aluminium or a strong nonferrous composite used when sewerage, storm water, water maintenance or inspections are required. It is a temporary self-ventilating design manhole grate to be used whenever the manhole cover is removed when operations are in progress around the manhole. The slots allow for natural light and airflow and it allows workers below ground to see through to the persons above; and vice versa. The retention features, or anti withdrawal features, further improve the safety of users operating in the area.

Traditionally these grates are composed of heavy metal and provide a hazard for workers on site. Folding of the grate and optionally providing means to hold or carry the grate for example via a hook type of member enables easy and safe handling of the grate.

Rollers are specifically designed to accommodate cables to relay items such as cameras and high pressure water jet rod fitting to below ground level. Rollers are designed to decrease injury to workers from high pressure water from jet rod both below and above ground level.

The improved grate system provides protection to workers and reduces injury to workers. For example, use of cables protects workers above ground from injury via jet rod heads which are delivered at high pressure. The cables restrict the motion and trajectory of attachments such as jet rod heads thereby reducing risk of injury. The grate retention members help prevent the grate from being dislodged from the manhole, for example, by potentially explosive sewer gasses, or slippage of the grate from the manhole area.

The perimeter and edges of the grate may be protected by pvc type of material such as rubber. It is preferable that the circular embodiment and temporary manhole grate (1) be formed of a lightweight material such as aluminium or even in some circumstances a suitably strong plastic or non-ferrous composite material. Where the temporary manhole cover will be used in a situation where operators may walk over it then it may be necessary to stiffen the plate by forming the plate with stiffening ribs on the underside of the temporary cover. The ventilation slot (6) is laser cut. The grate (1) is laser cut to drawing specifications and ventilation slots (6) are laser cut or via computer numeric control process. This can be realised in other shapes and embodiments of the current invention. In the alternative, when a strong plastic or non-ferrous composite is available, the use of 3D plastic injection molding may be used. The company logo may also be laser cut on the topside of the temporary manhole grate, for example. A semi concentric doorstop of the same material is welded to the topside to prevent the door from falling through. The doorstop and the invention is tested to industry weight load bearing specifications. In the preferred embodiment or any other embodiment of the temporary manhole grate, it will be covered with a textured powder coating with a sand finish to give a non-slip texture. Since the temporary manhole grate weighs less than 20 kg, it can be readily lifted into place by a single operator. When the hatch is opened, equipment can be safely passed through to the operator working in the confined space. This is convenient, as it is not required to remove the entire manhole cover in order to pass equipment, which will compromise the safety of all operators working in and around the manhole. It is to be understood that the invention is not limited to specific features shown or described since the means herein described comprises preferred forms of putting the invention into effect. Therefore, it should be appreciated that various other changes and modifications can be made to any embodiment described without departing from the spirit and scope of the invention.

VARIATIONS

The grate (1) may be designed to accommodate different shapes and sizes, allowing for different materials such as non-metallic materials including but not limited to strong plastics and composites. The utilization of these materials include but not limited to the following advantages:

Resistance to a wide range of chemical agents including acid rain and salt spray, conditions under which metal parts would suffer. This results in much reduced maintenance and repair costs;

Low weight--with substantial savings in weight over similar metal parts (25% the weight of steel, 30% lighter than aluminium);

Thermal properties--composite structures act as very good insulators, whilst retaining their shape while not becoming brittle in cold temperatures;

Strength--comparable to aluminium and steel, strength characteristics of many materials;

Safety--fibre-reinforced composites are low in electrical conductivity and are efficient fire retardants; and

Reduced cost--effective techniques have been developed which produce a post mold paint-finish type surface which requires no further processing, thus eliminating the need for time consuming and expensive finishing. The foregoing description is by way of example only, and may be varied considerably without departing from the scope of the present disclosure.

Referring now to Figs. 5A and 9A to 9C, an acrylic see-through sheet 211 of a transparent, plastic-like material such as, for example only, Plexiglass TM, may be attached to the underside of grate 100 if desired. Sheet 211 may be attached through purpose-built holes on grate 100, and configured to be interchangeable to suit different shaped and sized attachments, such as GC Clean, useable with the grate. Sheet 211 permits light to shine through any openings in the grate, while providing a barrier when needed against debris or rain into the manhole, or fumes, etc., out of the manhole.

The features described with respect to one embodiment may be applied to other embodiments, or combined with or interchanged with the features of other embodiments, as appropriate, without departing from the scope of the present disclosure.

Other embodiments of the disclosure will be apparent to those skilled in the art from consideration of the specification and practice of forms of the embodiments disclosed herein. It is intended that the specification and examples be considered as exemplary only, with a true scope and spirit of the disclosure being indicated by the following claims.

Claims (9)

1. What is claimed is: 1. A safety grate, comprising: a manhole cover body adapted to overlie a standard manhole; and at least one anti-withdrawal device configured to secure the cover to the manhole.
2. 2. The grate of claim 1, wherein the anti-withdrawal device includes opposed clamping surfaces to clamp the cover to the manhole.
3. 3. The grate of claim 1, wherein the anti-withdrawal device is longitudinally adjustable to accommodate a variation of manhole surface thicknesses.
4. 4. The grate of claim 1, wherein the anti-withdrawal device is a fixing configured to be inserted generally parallel to a horizontal plane of the cover.
5. 5. The grate of claim 4, wherein the anti-withdrawal device is a screw.
6. 6. The grate of claim 1, wherein said cover includes at least one vent hole sized and configured to permit passage of at least one of a antenna transmitter, remote camera, and/or light.
7. 7. The grate of claim 1, further comprising an Acrylic see-through sheet attachable to an underside of the grate to prevent high pressure jetting splashback, reduce exposure to harmful gasses, and absorb the impact of a Jetter head or object.
8. 8. The grate of claim 1, further comprising a hose retraction cleaner that cleans a hose and or contain hazardous solids or liquids including asbestos while the hose is being retracted.
9. 9. The grate of claim 8, wherein the hose retraction cleaner is a SG-Clean product.

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   100

   107

   FIGURE 1A

   SAFETY GRATE

   PURPOSELY DESIGNED PERFORATIONS, SEE THROUGH, AND VENT HOLES OF ANY SHAPE OR FORM

   102

   PURPOSELY BUILT ATTACHMENT, SEE THROUGH, SLOTS AND VENT HOLES OF ANY SHAPE OR FORM

   104

   100

   PURPOSELY BUILT ATTACHMENT, SEE THROUGH, AND VENT HOLES OF ANY SHAPE OR FORM

   FIGURE 1B

   2 of 7

   106

   ATTACHMENTS SUCH AS BUT NOT LIMITED TO EXAMPLE HOSE PULLED THROUGH ANTENA TRANSMITTERS, LIGHTS, REMOTE OPENING COVER HOSE AND CAMERA CAMERAS, SG-CLEAN, ANTIWITHDRAWAL DEVICES CABLE ROLLER ATTACHED TO SAFETY GRATE OR TEMPORARY MANHOLE COVER THROUGH PURPOSELY DESIGNED PERFORATIONS IN TOP AND BOTTOM SURFACE, SEE THROUGH, VENT HOLES AND SLOTS OF ANY SHAPE OR FORM. 2021103538

   100

   10

   SECTION K-K 106 FIGURE 2A 120

   SG-CLEAN MULTIPLE INTERCHANGEABLE ATTACHMENTS CAN BE SECURED TO SAFETY GRATE AT THE SAME TIME

   ANTI WITHDRAWAL FIXINGS

   100 210 10

   SECTION L-L LIGHT, REMOTE CAMERA OR ANTENA FACILITATING SEWAGE WORK

   122

   FIGURE 2B 106

   SG-CLEAN 100

   10

   ANTI WITHDRAWAL DEVICE 110 SECTION M-M FIGURE 2C

   3 of 7

   REMOVABLE, INTERCHANGEABLE INVENTION ATTACHEMENTS FIT IN EXISTING OR NEW TEMPORARY MANHOLE COVER INVENTIONS IN ANY DIRECTION BY WAY OF PURPOSELY DESIGNED PERFORATIONS IN TOP AND BOTTOM SURFACE, SEE THROUGH, VENT HOLES AND SLOTS OF ANY SHAPE 106 OR FORM.

   100 10 2021103538

   100 H DETAIL H FIGURE 3A SCALE 1 : 5

   107

   106

   FIGURE 3

   INVENTION ATTACHMENT CLEANS SEWER JETTING HOSE, OR SEWAGE EQUIPMENT LINES INCLUDING CAMERA LINES WHILE HOSE OR LINES ARE BEING RETRACTED. CAN BE USED IN CONJUNCTION WITH OTHER ATTACHMENTS OR ANTI WITHDRAWAL DEVICES 120

   EXAMPLE HOSE PULLED THROUGH OPENING 100 10 OVER HOSE AND CAMERA CABLE ROLLER

   SECTION G-G FIGURE 2D INVENTION CAN BE POSITIONED IN ANY DIRECTION THAT FACILITATES HOSE AND OPERATION RETRACTION.

   106

   EXAMPLE HOSE PULLED THROUGH OPENING COVER HOSE AND CAMERA CABLE ROLLER

   100 10

   FIGURE 2E SECTION J-J

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   100 2021103538

   100

   FIGURE 4

   INTERCHANGEABLE SEE THROUGH ACRYLIC SHEET COVERING UNUSED PERFORATIONS TO PREVENT HIGH PRESSURE WATER SPLASHBACK AND TO AID IN ABSORBING IMPACT OF A SEWER JETTER HEAD OR OBJECT HEIGHT ADJUSTED BY ROTATING TOP OF ANTI WITHDRAWAL DEVICE. CAN BE ROTATED BY HAND, MANHOLE PERIMETER WITH LEVER OR WHEEL ATTACHMENT, POWER TOOLS OR ANY TOOL THAT FACILITATES OR AIDS ROTARY MOTION.

   118

   118 211 110

   ADJUSTABLE ANTI WITHDRAWAL DEVICE

   SECTION A-A 112

   FIGURE 5A TOP MOUNTED ANTI WITHDRAWAL DEVICE ATTACHES TO SAFETYGRATE FROM TOP THROUGH PURPOSELY MADE PERFORATIONS , SEE THROUGH, VENT HOLES AND SLOTS OF ANY SHAPE OR FORM.

   DEVICE LOCKS INTO PLACE UPON INSERTION, OR IS ROTATED TO LOCK INTO PLACE ONCE INSERTED INTO ITS INTENDED LOCATION.

   100

   TEMPORARY MANHOLE COVER CLAMPS TO TOP SURFACE 10

   FIGURE 5 10

   SECTION B-B

   FIGURE 5B ANTI WTHDRAWAL DEVICE CLAMPS ONTO ANY SURFACE OF ANY DEPTH

   5 of 7

   INVENTION ATTACHEMENTS FIT IN EXISTING OR NEW TEMPORARY MANHOLE COVER INVENTIONS IN ANY DIRECTION BY WAY OF PURPOSELY DESIGNED PERFORATIONS IN TOP AND BOTTOM SURFACE, SEE THROUGH, VENT HOLES AND SLOTS OF ANY SHAPE OR FORM. INVENTION AND COMPONENTS MADE OF ANY METAL, ALLOY, PLASTICS OR COMPOSITES WITH ANY SURFACE FINISH, TREATMENT OR COLOUR.

   HEIGHT ADJUSTED BY ROTATING TOP OF ANTI WITHDRAWAL DEVICE. CAN BE ROTATED BY HAND, WITH LEVER OR WHEEL ATTACHMENT, POWER TOOLS OR ANY TOOL THAT FACILITATES OR AIDS ROTARY MOTION.

   118 2021103538

   SINGULAR OR PLURAL PLATES OR OBJECTS OF ANY SHAPE OR FORM RESTRAIN FORWARD, LATERAL, ROTARY MOVEMENT TOP PLATE OR MATERIAL ONCE ANTI WITHDRAWAL DEVICE IS INSERTED INTO FIXED TO LIEAR MOTION GUIDE PURPOSELY DESIGNED PERFORATIONS IN TOP AND ACTS AS TOP SURFACE CLAMP BOTTOM SURFACE, SEE THROUGH, VENT HOLES AND SLOTS OF ANY SHAPE OR FORM OF TEMPORARY MANHOLE COVER.

   116

   LINEAR MOTION GUIDE PREVENTS LOCKING PLATE FROM ROTATING AROUND AXIS OF TRAPEZOIDAL SCREW, ACME SCREW, BOLT OR ANY ROTATING LINEAR MOTION PERCURSOR TRAPEZOIDAL SCREW, OR ACTUATOR. ACME SCREW, BOLT OR ANY ROTATING LINEAR MOTION PERCURSOR OR ACTUATOR. ROTATING IT CAUSES LOCKING PLATE TO MOVE UP OR DOWN. ANTI SLIP SURFACE OF ANY SHAPE CN BE MADE OF ANY DIAMETER TO SUIT DIFFERENT LENGTHS OR FLAT SURFACE

   LOCKING PLATE OF ANY SHAPE OR FORM TRAPEZOIDAL SCREW, ACTS AS BOTTOM SURFACE CLAMP ACME SCREW, CAN MOVE UP OR DOWN TO ADJUST TO ANY HEIGHT OR DEPTH BOLT OR ANY ROTATING LINEAR MOTION NUT OR FIXING

   112

   BOTTOM PLATE OR MATERIAL SINGULAR OR PLURAL PLATES OR OBJECTS OF ANY SHAPE OR FORM RESTRAIN FORWARD, LATERAL, ROTARY MOVEMENT FIGURE 6B FIXED TO LIEAR MOTION GUIDE ONCE ANTI WITHDRAWAL DEVICE IS INSERTED INTO PURPOSELY DESIGNED PERFORATIONS IN TOP AND BOTTOM SURFACE, SEE THROUGH, VENT HOLES AND SLOTS OF ANY SHAPE OR FORM OF TEMPORARY MANHOLE COVER. 118

   116

   FIGURE 6C 116 118 110 ANY HEIGHT LENGTH TO SUIT ANY AND ALL MANHOLE DEPTHS

   110

   116

   LOCKING PLATE CAN TRAVEL UP AND DOWN AND BE ADJUSTED TO ANY HEIGHT OR DEPTH

   114 114

   112

   FIGURE 6D FIGURE 6A

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   CIRCULAR FIXINGS ADJUSTED TO SUIT ANY SIZE MANHOLE SINGULAR OR A PLURALITY OF FIXINGS OF ANY SIZE MATERIAL, SHAPE AND COLOUR.

   FIXINGS CAN BE CONFIGURED FOR ANY MANHOLE DEPTH AND OPENING SIZE. FIXINGS CAN BE SECURED TO TEMPORARY COVER THROUGH PURPOSELY MADE HOLES, OR EXISTING HOLES OR ATTACHEMENTS

   PROTRUSION OF FIXINGS CAN BE ADJUSTED BY ROTATING FIXING BY HAND, 210 WITH LEVER OR WHEEL ATTACHMENT, POWER TOOLS OR ANY TOOL THAT FACILITATES OR AIDS ROTARY MOTION. .

   FIGURE 7 FIXINGS PRESS INTO MANHOLE SURFACE OR WALL TO RESTRAINT IN PLACE

   DETAIL D SCALE 1 : 4

   FIGURE 8A

   210 210

   DETAIL F SCALE 1 : 4

   E FIGURE 8C MANHOLE PERIMETER

   D

   10

   E F FIGURE 8 10

   210

   SECTION E-E FIGURE 8B

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   SEWER JETTING WITHDRAWAL SCENARIO

   211 10 211 211 2021103538

   110 110

   110

   SEWER JETTING HEAD BEING LOWERED SEWER JETTING HEAD FACING UP TOWARDS TEMPORARY MANHOLE SEWER JETTING ACCELERATING UPWARDS AND IMPACTING INSIDE MANHOLE COVER. HIGH PRESSURE JET ACCELERATING JETTER HEAD TEMPORARY MANHOLE COVER. INTERCHANGEABLE SEE TOWARDS TEMPORARY MANHOLE COVER THROUGH ACRYLIC SHEET ABSORBING IMPACT ON LID AND WEAK POINTS. ANTI WITHDRAWAL DEVICE RESTRAINING TEMPORARY MANHOLE COVER FROM DISLODGEMENT.

   FIGURE 9A FIGURE 9B FIGURE 9C

   SECTION C-C