The device according to the present invention has been devised in order to facilitate the operations of workers in charge of construction, maintenance and control of drainage systems, underground tanks etc.

Moreover, the device according to the present invention guarantees the workers'safety during the manual handling of loads, in compliance with the current regulations on safety and health in working environments.

As a matter of fact, during the aforementioned operations, workers are frequently requested to lay down and remove manholes, grates or heavy metal panels.

Today these operations are carried out manually, with the help of generic tools, such as levers, crowbars or hooks, with extreme discomfort and considerable effort for the workers. This is because no specific equipment exists on the market capable of replacing the physical activity of the workers.

Difficulties increase also because the various types of manholes or grates have different characteristics, since they present different fixing holes and/or wrenches.

This means that specific equipment must be used to lay down or lift a specific type of manholes or grates and that the same equipment may not be usable for different models of the same manufacture.

The purpose of the present invention is to realise a device used to lay down, lift and handle manholes, grates and metal plates in and similar items without physical effort on the workers'side and at the same. time capable of carrying out the aforementioned operations on every type of metal manufacture, regardless of its specific structural and functional

characteristics.

The device according to the present invention consists in a trolley that supports a permanent magnet, of known type, with high attraction, that can be activated or deactivated by the user according to his specific operating requirements.

The magnet can make vertical alternate travels in the bearing structure of the trolley. Therefore, firstly, the trolley is placed over the manhole or grate to be handled, secondly the magnet is lowered until it touches the metal manufacture and finally the attraction force of the magnet is activated.

It appears evident that the metal manufacture firmly adheres to the magnet. Then the slide supporting the magnet is raised, extracting the metal manufacture from its housing.

It appears also evident that the inverse operating sequence can be used to put the metal manufacture back in its housing.

It must be noted that, apart from vertically alternate travels, the magnet can also make horizontal alternate travels, as well as rotations to the right and left with respect to the longitudinal axis of the trolley according to the present invention.

The high manoeuvrability of the magnet ensure effective operation when the device according to the present invention is used to lift manholes or grates and put them back in their housings.

The possibility of adjusting the magnet's position allows the operator to place the magnet over the metal manufacture to be handled without moving the trolley, with perfect alignment and balance.

The possibility of adjusting the magnet's position together with the capability of slightly moving the trolley's wheels, although braked, is extremely advantageous when the operator needs to place the metal manufacture over its housing to put it back there.

It can be said that the device according to the present invention is provided with the possibility of self-centring the position. of the manhole attached to the trolley with respect to its housing.

As a matter of fact, the operator only needs to lower the manhole

attached to the trolley in tilted position so that a perimeter section of the manhole can match exactly the corresponding section of the perimeter border of its housing.

In particular, in case of circular manholes, the operator can"match" any section of the manhole perimeter with the with a section of the housing perimeter; in case of rectangular or square manholes, the operator only needs to"match"a corner of the manhole with the corresponding corner of the housing.

Once the"matching"has been completed, the operator can easily lower the manhole to put it back in its housing with perfect horizontal alignment.

For major clarity the description of the invention continues with reference to the enclosed drawings, which are intended for purposes of illustration and not in a limiting sense, whereby : - fig. 1 is an axonometric side view of the trolley according to the present invention; - fig. 2 is an axonometric three-quarter rear view of the trolley according to the present invention.

With reference to the aforementioned figures, the trolley according to the present invention comprises a triangular bearing frame (1) mounted on three wheels (2,3), of which the two side-rear wheels (2) are fixed to the lower ends of suitable legs (1a), and the central-front wheel (3) is a double pivoting wheel, being mounted at the lower end of a pin (4) with vertical axis that turns inside a support cylindrical jacket (4a) fixed on the vertex of the bearing frame (1) which is slightly lower than the back part of the frame (1).

The double front wheel (3) is assisted by a pedal parking brake (3a) used to firmly block the trolley once the exact operating position over the manhole has been reached.

In particular, it must be noted that the rotations of the pin (4) around its axis are caused by means of a long bar (5) with handle (5a),. which is pivoted on a shelf fixed on the front of the cylindrical jacket (4a) of the pin (4). In this way the bar (5) can go from an exactly vertical position to a subvertical

position inclined towards the outside of the trolley.

When the bar (5) is in subvertical position, it can be used to set any curving angle to the double front wheel (3) and consequently to the trolley. At the same time the handle (5a) can be used to actuate the bar (5) in order to pull or push the trolley.

In order to move the trolley in a perfectly linear direction, the bar (5) can be replaced in perfectly vertical position and exactly engaged within the arms (6a) of a collapsible fork (6) that is supported and pivoted at the top of the jacket (4a) of the turning pin (4) (see figure 2).

In this operating position the arms (6a) of the fork (6) are horizontal and arranged according to an axis parallel to the longitudinal axis of the trolley.

It appears evident that when the bar (5) is engaged within the arms (6a) of the fork (6) it cannot move, being blocked in a position that corresponds to a perfectly parallel position of the double front wheel (3) with respect to the two side wheels.

In order to restore the movement of the double front wheel (3) the operator only needs to incline the bar (5) externally, in order to disengage it from the fork (6). In order to avoid interference with the rotations of the bar (5), the fork (6) can be overturned backwards, on the back of the cylindrical jacket (4a) of the turning pin (4), towards a position in which it does not interfere with the movement of the bar (5) (see figure 1).

The back of the bearing frame (1) of the trolley is provided with a wide transversal rectilinear window (7). Rails (7a) are mounted on the borders of the window (7) to support a slide (8). An hydraulic jack (9) is vertically fixed to the slide (8). The stem (10) of the jack (9) that lies underneath the slide (8), supports a permanent magnet (11) with the interposition of an articulated joint (not shown in the enclosed figures). The magnet (11) can be activated/deactivated, such as the one marketed by Tecnomagnete with the name"MaxX".

A tubular part (12) with hand grip (12a) is horizontally welded on top of the jack (9). The hand grip (12a) can be used by the operator to cause

rightwards or leftwards travels of the slide (8) and consequently of the jack (9) joined to it.

A long manoeuvring arm (13) with handle (13a) is fixed to the lower end of the permanent magnet (11). The magnet (11) is frontally provided with a counterweight (11 a) in order to balance the weight of the arm (13) and maintain a horizontal direction in idle position, even if attached to the articulated joint.

The manoeuvring arm (13) is used to give any inclination to the magnet (11) with respect to the horizontal plane, by taking advantage of the fact the same is attached to the articulated joint.

It appears evident that the permanent magnet (11) mounted on the trolley according to the present invention can make alternate travels in transversal direction thanks to the slide (8), as well as alternate travels in vertical direction thanks to the jack (9) to which is attached, and also any type of oscillations with respect to the horizontal plane thanks to the articulated joint.

This characteristic, together with the possibility offered by the three wheels (2,3) to move the trolley forwards and backwards both in rectilinear and curvilinear direction, ensures high versatility of use for the operators who must place the trolley-and more exactly the magnet (11)-exactly above the manhole (to extract it from its housing) or above its housing (to put it back).

In order to facilitate the perfect alignment of the trolley with respect to the manhole or its housing, the double front wheel (3) is provided with clutch : even when braked, the double front wheel (3) is still capable of turning under a strong thrust; this ensures the possibility of make short controlled movements of the trolley that are necessary for the final adjustment of the magnet position above the manhole.

As regards the operation of the hydraulic jack (9), it must be said that an oil tank (14) with pump (14a) is fixed on the bearing, frame (1) of the trolley, behind the transversal window (7) to actuate the jack (9a); it being provided that the jack (9) and the fixed tank (14) are connected with a hose

(15).

In particular, the operator can actuate the pump (14a) with a lever (16); the lever (16) can. be used to pump oil from the tank (14) to the jack (9) to raise the stem (10) from its extracted position.

A smaller lever (17) is used for the opposite operation, that is to open the valve that allows the oil to pass from the jack (9) to the tank (14), with consequent lowering of the stem (10) of the jack by means of gravity, under the weight of the permanent magnet (11) and of the metal manufacture attached to it.

In particular, the small lever (17) is used for the fine adjustment of the valve opening and closing in order to exactly adjust the speed and the various descending steps of the stem (10) of the jack (9).

Finally, the trolley is provided with a long tubular bar with circular section (not shown in the enclosed figures) that in idle position is inserted vertically in a suitable tubular liner (18) externally welded on one of the two legs (1 a) of the bearing frame (1).

The tubular bar can be easily extracted from the liner (18) and inserted in a corresponding sleeve (lob) that protrudes from the permanent magnet (11). By rotating the bar and the sleeve (11 b) with it, the operator can activate and deactivate the permanent magnet (11).

The trolley is also provided with a lever (19) mounted on the bearing frame (1) in front of the transversal window (7), which is used to block the slide (8) that supports the jack (9) in the desired position according to the operation to be carried out by the operator.

Finally, protection covers (20) are fixed on the two sides of the bearing frame (1) of the trolley according to the present invention, by means of suitable pairs of arms (20a), in order to contain possible oscillations of the manhole attached to the permanent magnet (11), especially during transfers.