Adjustable fork for heavy loads

1 . An adjustable fork, comprising:

a main frame ( 2 );

a first and a second prong ( 5 , 6 ), associated with the main frame ( 2 );

a first slider ( 3 ) and a second slider ( 4 ), associated with the main frame ( 2 );

the first slider ( 3 ) is slidable along an adjustment direction (X) away from and towards the second slider ( 4 ) for a predetermined adjustment stroke of the first slider ( 3 );

the second slider ( 4 ) is slidable along the adjustment direction (X) away from and towards the first slider ( 3 ) for a predetermined adjustment stroke of the second slider ( 4 );

the first prong ( 5 ) is associated with the first slider ( 3 ) and is slidable, relative to the first slider ( 3 ), along the adjustment direction (X) for a predetermined adjustment stroke of the first prong ( 5 );

the second prong ( 6 ) is associated with the second slider ( 4 ) and is slidable, relative to the second slider ( 4 ), along the adjustment direction (X) for a predetermined adjustment stroke of the second prong ( 6 );

wherein a configuration of minimum width is obtained when the sliders ( 3 , 4 ) are moved towards each other to a minimum distance position of the sliders ( 3 , 4 );

wherein the configuration of minimum width is not dependent on a position of the prongs ( 5 , 6 ), such that the configuration of minimum width is obtainable when the prongs ( 5 , 6 ) are in a minimum distance position of the prongs ( 5 , 6 ), and when the prongs ( 5 , 6 ) are in a maximum distance position of the prongs ( 5 , 6 ).

2 . The adjustable fork according to claim 1 , comprising:

an actuator unit ( 30 , 40 , 50 , 60 ), designed for determining said adjustment strokes of the first slider, the second slider, the first prong and the second prong;

a control system, connected to the actuator unit ( 30 , 40 , 50 , 60 ) and configured for activating the actuator unit in response to at least one widening command and to a narrowing command;

wherein in a presence of an active widening command, the control system determines a moving of the prongs ( 5 , 6 ) away from each other up to the maximum distance position of the prongs ( 5 , 6 ), followed by a moving away from each other of the sliders ( 3 , 4 );

wherein in a presence of an active narrowing command, the control system determines a moving of the prongs ( 5 , 6 ) towards each other up to the minimum distance position of the prongs ( 5 , 6 ), followed by a moving towards each other of the sliders ( 3 , 4 ).

3 . The adjustable fork according to claim 2 , wherein:

the control system is configured for activating the actuator unit in response to at least a first lateral movement command and to a second lateral movement command;

the first lateral movement command determines a simultaneous movement of the sliders ( 3 , 4 ) in a first direction along the adjustment direction (X);

the second lateral movement command determines a simultaneous movement of the sliders ( 3 , 4 ) in a second direction, opposite to the first direction, along the adjustment direction (X).

4 . The adjustable fork according to claim 2 , comprising:

a first actuator ( 30 ), connected to the first slider ( 3 ) and designed for determining the adjustment stroke of the first slider ( 3 );

a second actuator ( 40 ), connected to the second slider ( 4 ) and designed for determining the adjustment stroke of the second slider ( 4 );

a third actuator ( 50 ), connected to the first prong ( 5 ) and designed for determining the adjustment stroke of the first prong ( 5 );

a fourth actuator ( 60 ), connected to the second prong ( 6 ) and designed for determining the adjustment stroke of the second prong ( 6 );

wherein the control system is connected to said actuators ( 30 , 40 , 50 , 60 ) and is configured for activating each actuator in response to said widening and narrowing commands.

5 . The adjustable fork according to claim 4 , wherein said actuators ( 30 , 40 , 50 , 60 ) are hydraulic actuators, and wherein the control system comprises a hydraulic circuit.

6 . The adjustable fork according to claim 5 , wherein said actuators ( 30 , 40 , 50 , 60 ) each comprise a first chamber (C 1 ) and a second chamber (C 2 ), separated from each other by a piston (P), and wherein the control system comprises:

a first supply line ( 7 ), which connects the first chamber (C 1 ) of the third and fourth actuators ( 50 , 60 ) with a first coupling opening (V 1 );

a second supply line ( 8 ), which connects the second chamber (C 2 ) of the third and fourth actuators ( 50 , 60 ) with a second coupling opening (V 2 );

a third supply line ( 9 ), which connects the first chamber (C 1 ) of the first and second actuators ( 30 , 40 ) with said first coupling opening (V 1 );

a fourth supply line ( 10 ), which connects the first chamber (C 1 ) of the first and second actuators ( 30 , 40 ) with said second coupling opening (V 2 );

a first distributor (D 1 ), connected to the first and second coupling openings (V 1 , V 2 ), which may adopt a first position, in which the first distributor connects the first coupling opening (V 1 ) with a source of pressurised fluid and the second coupling opening (V 2 ) with a discharge, a second position, in which the first distributor connects the first coupling opening (V 1 ) with said discharge and the second coupling opening (V 2 ) with said source of pressurised fluid, and a central position, in which neither of the two coupling openings is connected to the source of pressurised fluid;

sequence means which, with the first distributor (D 1 ) in the first position, are designed to direct the pressurised fluid to the first supply line ( 7 ) until reaching a predetermined pressure and, subsequently, to direct the pressurised fluid to the third supply line ( 9 );

with the first distributor (D 1 ) at the second position, the sequence means are set up to direct the pressurised fluid to the second supply line ( 8 ) until reaching a predetermined pressure and, subsequently, to direct the pressurised fluid to the fourth supply line ( 10 ).

7 . The adjustable fork according to claim 6 , comprising:

a fifth supply line ( 11 ), which connects the second chamber (C 2 ) of the first actuator ( 30 ) with a third coupling opening (V 3 );

a sixth supply line ( 12 ), which connects the second chamber (C 2 ) of the second actuator ( 40 ) with a fourth coupling opening (V 4 )

a second distributor (D 2 ), connected to the third and fourth coupling openings (V 3 , V 4 ), which may adopt a first position, in which the second distributor connects the third coupling opening (V 3 ) with a source of pressurised fluid and the fourth coupling opening (V 4 ) with a discharge, a second position, in which the second distributor connects the third coupling opening (V 3 ) with said discharge and the fourth coupling opening (V 4 ) with said source of pressurised fluid, and a central position, in which neither of the two coupling openings (V 3 , V 4 ) is connected to the source of pressurised fluid;

a recirculation duct ( 13 ), which connects the first chamber (C 1 ) of the first actuator ( 30 ) with the first chamber (C 1 ) of the second actuator ( 40 ).

8 . The adjustable fork according to claim 7 , wherein the third supply line ( 9 ) is connected to the recirculation duct ( 13 ).

9 . The adjustable fork according to claim 6 , wherein the fourth supply line ( 10 ) comprises a divider ( 10 a ) from which two branches ( 101 , 102 ) of the fourth supply line ( 10 ) extend, connected respectively to the second chamber (C 2 ) of the first actuator ( 30 ) and to the second chamber (C 2 ) of the second actuator ( 40 ).

10 . The adjustable fork according to claim 9 , wherein:

a first branch ( 101 ) of the fourth supply line ( 10 ) comprises an enabling valve ( 10 c ), movable between an open position, in which the enabling valve allows a flow along the first branch ( 101 ), and a closed position, in which the enabling valve prevents the flow along the first branch ( 101 );

the enabling valve ( 10 c ) is activated in the closed position by a pressure present in the fifth supply line ( 11 ) and in the sixth supply line ( 12 ), whilst the enabling valve is activated in the open position by a pressure present in the first branch ( 101 ).

11 . The adjustable fork according to claim 6 , wherein the second supply line ( 8 ) comprises a divider ( 8 a ) from which two branches ( 81 , 82 ) of the second supply line ( 8 ) extend, connected, respectively, to the second chamber (C 2 ) of the third actuator ( 50 ) and to the second chamber (C 2 ) of the fourth actuator ( 60 ).

12 . The adjustable fork according to claim 6 , wherein the first and second actuators ( 30 , 40 ) are aligned with each other and connected at one end from a side of the respective first chambers (C 1 ), with rods ( 31 , 41 ) of the first and second actuators ( 30 , 40 ) facing on opposite sides.

13 . The adjustable fork according to claim 12 , wherein the first and the second actuators ( 30 , 40 ) are connected to the main frame ( 2 ); the rod ( 31 ) of the first actuator ( 30 ) is connected to the first slider ( 3 ); the rod ( 41 ) of the second actuator ( 40 ) is connected to the second slider ( 4 ).

14 . An adjustable fork, comprising:

a main frame ( 2 );

a first and a second prong ( 5 , 6 ), associated with the main frame ( 2 );

a first slider ( 3 ) and a second slider ( 4 ), associated with the main frame ( 2 );

the first slider ( 3 ) is slidable along an adjustment direction (X) away from and towards the second slider ( 4 ) for a predetermined adjustment stroke of the first slider ( 3 );

the second slider ( 4 ) is slidable along the adjustment direction (X) away from and towards the first slider ( 3 ) for a predetermined adjustment stroke of the second slider ( 4 );

the first prong ( 5 ) is associated with the first slider ( 3 ) and is slidable, relative to the first slider ( 3 ), along the adjustment direction (X) for a predetermined adjustment stroke of the first prong ( 5 );

the second prong ( 6 ) is associated with the second slider ( 4 ) and is slidable, relative to the second slider ( 4 ), along the adjustment direction (X) for a predetermined adjustment stroke of the second prong ( 6 );

a first actuator ( 30 ), connected to the first slider ( 3 ) and designed for determining the adjustment stroke of the first slider ( 3 );

a second actuator ( 40 ), connected to the second slider ( 4 ) and designed for determining the adjustment stroke of the second slider ( 4 );

wherein the first prong ( 5 ) is slidable on the first slider ( 3 ) such that the first prong ( 5 ) is slidable in front of the first actuator ( 30 );

wherein the second prong ( 6 ) is slidable on the second slider ( 4 ) such that the second prong ( 6 ) is slidable in front of the second actuator ( 40 ).

15 . An adjustable fork, comprising:

a main frame ( 2 );

a first and a second prong ( 5 , 6 ), associated with the main frame ( 2 );

a first slider ( 3 ) and a second slider ( 4 ), associated with the main frame ( 2 );

the first slider ( 3 ) is slidable along an adjustment direction (X) away from and towards the second slider ( 4 ) for a predetermined adjustment stroke of the first slider ( 3 );

the second slider ( 4 ) is slidable along the adjustment direction (X) away from and towards the first slider ( 3 ) for a predetermined adjustment stroke of the second slider ( 4 );

the first prong ( 5 ) is associated with the first slider ( 3 ) and is slidable, relative to the first slider ( 3 ), along the adjustment direction (X) for a predetermined adjustment stroke of the first prong ( 5 );

the second prong ( 6 ) is associated with the second slider ( 4 ) and is slidable, relative to the second slider ( 4 ), along the adjustment direction (X) for a predetermined adjustment stroke of the second prong ( 6 );

an actuator unit ( 30 , 40 , 50 , 60 ), designed for determining said adjustment strokes of the first slider, the second slider, the first prong and the second prong;

a control system, connected to the actuator unit ( 30 , 40 , 50 , 60 ) and configured for activating the actuator unit in response to at least one widening command and to a narrowing command;

wherein in a presence of an active widening command, the control system determines a moving of the prongs ( 5 , 6 ) away from each other up to a maximum distance position, followed by a moving away from each other of the sliders ( 3 , 4 );

wherein in a presence of an active narrowing command, the control system determines a moving of the prongs ( 5 , 6 ) towards each other up to a minimum distance position, followed by a moving towards each other of the sliders ( 3 , 4 );

a first actuator ( 30 ), connected to the first slider ( 3 ) and designed for determining the adjustment stroke of the first slider ( 3 );

a second actuator ( 40 ), connected to the second slider ( 4 ) and designed for determining the adjustment stroke of the second slider ( 4 );

a third actuator ( 50 ), connected to the first prong ( 5 ) and designed for determining the adjustment stroke of the first prong ( 5 );

a fourth actuator ( 60 ), connected to the second prong ( 6 ) and designed for determining the adjustment stroke of the second prong ( 6 );

wherein the control system is connected to said actuators ( 30 , 40 , 50 , 60 ) and is configured for activating each actuator in response to said widening and narrowing commands;

wherein said actuators ( 30 , 40 , 50 , 60 ) are hydraulic actuators, and wherein the control system comprises a hydraulic circuit;

wherein said actuators ( 30 , 40 , 50 , 60 ) each comprise a first chamber (C 1 ) and a second chamber (C 2 ), separated from each other by a piston (P), and wherein the control system comprises:

a first supply line ( 7 ), which connects the first chamber (C 1 ) of the third and fourth actuators ( 50 , 60 ) with a first coupling opening (V 1 );

a second supply line ( 8 ), which connects the second chamber (C 2 ) of the third and fourth actuators ( 50 , 60 ) with a second coupling opening (V 2 );

a third supply line ( 9 ), which connects the first chamber (C 1 ) of the first and second actuators ( 30 , 40 ) with said first coupling opening (V 1 );

a fourth supply line ( 10 ), which connects the first chamber (C 1 ) of the first and second actuators ( 30 , 40 ) with said second coupling opening (V 2 );

a first distributor (D 1 ), connected to the first and second coupling openings (V 1 , V 2 ), which may adopt a first position, in which the first distributor connects the first coupling opening (V 1 ) with a source of pressurised fluid and the second coupling opening (V 2 ) with a discharge, a second position, in which the first distributor connects the first coupling opening (V 1 ) with said discharge and the second coupling opening (V 2 ) with said source of pressurised fluid, and a central position, in which neither of the two coupling openings is connected to the source of pressurised fluid;

sequence means which, with the first distributor (D 1 ) in the first position, are designed to direct the pressurised fluid to the first supply line ( 7 ) until reaching a predetermined pressure and, subsequently, to direct the pressurised fluid to the third supply line ( 9 );

with the first distributor (D 1 ) at the second position, the sequence means are set up to direct the pressurised fluid to the second supply line ( 8 ) until reaching a predetermined pressure and, subsequently, to direct the pressurised fluid to the fourth supply line ( 10 ).