Public works vehicle provided with counterweight lifting system

Abstract

A public works vehicle has a base, moving means supporting the base, brackets joined to the frame of the base, a lifting system suitable for lifting a counterweight. The lifting system has a first arm hinged to the frame, at least one thrust actuator connected to the frame and to the first arm to move the first arm, a second arm slidingly mounted with respect to the first arm, a lifting actuator connected to the first arm and to the second arm to move the second arm, a connection system connected to the second arm and to the counterweight.

Claims

1. Public works vehicle comprising: a base containing at least one engine, said base comprising a frame and a substantially vertical back wall; moving means supporting the base; at least one bracket joined to the frame; a counterweight having a front wall intended to be faced towards said back wall of the base; said counterweight being intended to be fixed and supported by said brackets; a lifting system intended to lift said counterweight; wherein said lifting system comprises: a first arm hinged to said frame to go from a retracted position, wherein the first arm is disposed vertically near the back wall of the base, to an extracted position, wherein the first arm protrudes from the back wall of the base; at least one thrust actuator connected to the frame and to the first arm to move the first arm; a second arm slidingly mounted with respect to the first arm to go from a retracted position with respect to the first arm to an extracted position, wherein it protrudes from the first arm; a lifting actuator connected to the first arm and to the second arm to move the second arm; a connection system connected to the second arm and to the counterweight wherein the second arm has an eccentric shape, that is a non-linear shape; the second arm comprises a rearward-protruding end portion; said end portion of the second arm has a shaft and the connection system is hinged to said shaft; the distance between the external surface of the first arm and an axis parallel to the axis of the first arm and passing through the axis of the shaft of the end portion of the second arm is higher than the distance between the center of gravity of the counterweight and the front wall of the counterweight.

2. The public works vehicle of claim 1, wherein said shaft is disposed along a horizontal axis parallel to the back part and said connection system comprises articulated arms or ropes or actuators connected to said shaft and to said counterweight.

3. The public works vehicle of claim 2, wherein said connection system comprises an articulated arm comprising a first connecting rod hinged to said shaft and a second connecting rod hinged to the first connecting-rod.

4. The public works vehicle of claim 3, wherein said second connecting rod comprises a pin that is engaged in a hole of a flange that protrudes in upper position from the counterweight.

5. The public works vehicle of claim 1, comprising two thrust actuators disposed on opposite sides of said first arm.

6. The public works vehicle of claim 1, wherein said at least one thrust actuator and said lifting actuator are hydraulic actuators.

7. The public works vehicle of claim 6, wherein said at least one thrust actuator comprises a cylinder connected to the frame of the public works vehicle and a piston connected to said first arm.

8. The public works vehicle of claim 1, wherein said brackets protrude from the back wall of the base in such manner to generate a housing that receives said first arm.

9. The public works vehicle of claim 1, wherein said counterweight has centering pins that protrude in lower position from the counterweight and are engaged in centering housings obtained in said brackets.

10. The public works vehicle of claim 1, wherein said public works vehicle is a drilling machine or a boring machine.

Description

BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWINGS

(1) Additional features of the invention will appear clearer from the detailed description below, which refers to merely illustrative, not limiting embodiments, wherein:

(2) FIG. 1 is a perspective view of an excavator of the prior art, in which the counterweight has been removed.

(3) FIG. 2 is a rear view of the excavator of FIG. 1.

(4) FIGS. 3 and 4 are views of details of the excavator of the prior art shown in FIGS. 1 and 2.

(5) FIG. 5 is a perspective view of an excavator of the prior art, provided with a first type of counterweight lifting system.

(6) FIG. 6 is a partially interrupted view of the excavator of FIG. 5, in which the counterweight has been removed.

(7) FIG. 7 is a partially interrupted perspective view of an excavator of the prior art, provided with a second type of counterweight lifting system.

(8) FIG. 8 is a partially interrupted view of the excavator of FIG. 7.

(9) FIG. 9 is a perspective view of a drilling machine of the prior art, in idle condition.

(10) FIG. 10 is a perspective view of the drilling machine of FIG. 9, in working condition, and of a crane used to lift the counterweight.

(11) FIG. 11 is a partially interrupted sectional view of a public works vehicle with counterweight lifting system according to the invention, in which the counterweight is placed on the ground and disconnected from the lifting system.

(12) FIG. 12 is a side view of the vehicle of FIG. 11, in which the counterweight is lifted and connected to the lifting system, in an initial lifting step.

(13) FIG. 13 is the same view as FIG. 12, wherein the counterweight is moved closer to the support brackets.

(14) FIG. 14 is a sectional view of the vehicle of the invention, in which the counterweight is positioned above the support brackets.

(15) FIG. 15 is the same view as FIG. 14, in which the counterweight is supported by the support brackets.

(16) FIG. 16 is a sectional view of a lower portion of the counterweight and of a bracket of the frame of the public works vehicle.

DETAILED DESCRIPTION OF THE INVENTION

(17) With reference to FIGS. 11-15, a public works vehicle (1), according to the invention, such as a drilling or a boring machine, is disclosed.

(18) The public works vehicle (1) comprises a base (2) mounted on moving means (3), such as tracks. The base (2) has a frame (20) and a substantially vertical back wall (21). The base (2) houses one or more engines of the vehicle, which are closed by a hood (25) that protrude in upper position from the base (2).

(19) The public works vehicle (1) comprises a counterweight (4) and a lifting system (5) to lift and support the counterweight (4). The lifting system (5) is mounted in the frame (20) of the base, in such a way to protrude in rearward position from the back wall (21) of the base.

(20) With reference to FIG. 11, the counterweight (4) is a standard counterweight of the type that is normally used in excavators. The counterweight (4) has a parallelepiped body comprising a substantially planar and vertical front wall (42) and a back wall (43). The counterweight (4) has a lower seat (44) that is frontally open and provided with a planar horizontal surface (44a).

(21) The counterweight (4) has a center of gravity (G). Two flanges (45) protrude in upper position from the counterweight. The flanges (45) have holes (46) with horizontal axis intersecting a vertical axis passing through the center of gravity (G). A distance (e1) is defined between the center of gravity (G) and the front wall (42) of the counterweight.

(22) With reference to FIGS. 11-15, the public works vehicle (1) comprises two brackets (122) joined to the frame (20) and protruding in rearward position from the back wall. The brackets (122) are suitable for supporting the counterweight (4).

(23) Instead of two brackets (122), a single bracket can be used, which is shorter than the brackets (122) shown in FIGS. 11-16. In such a case, the counterweight (4) can be positioned at a higher distance and height, that is in the center of a trolley.

(24) With reference to FIG. 16, the counterweight (4) comprises centering pins (47) that protrude in lower position from the counterweight to be engaged in centering housings (123) obtained in the brackets (122). Advantageously, the centering pins (47) of the counterweight have a truncated-conical shape and the centering housings (123) of the brackets have a tapered or flared shape.

(25) The lifting system (5) comprises a first arm (50); advantageously, the first arm is an internally empty female arm. The first arm (50) is hinged to the frame (20) of the base of the vehicle, in a pivoting axis (50a) disposed in a central position of the back wall (21) of the base of the vehicle, between the two brackets (122). The length of the brackets (122) has been expressly increased with respect to the brackets of the prior art in order to create a housing for the first arm (50).

(26) The pivoting axis (50a) of the first arm (50) is a horizontal axis, in parallel position with respect to the back wall (21) of the base. In view of the above, the first arm (50) can rotate around its pivoting axis to pass from a retracted position, in which the first arm is arm is disposed vertically near the back wall (21) of the base, to an extracted position, in which the first arm protrudes in rearward position from the back wall (21) of the base and is tilted with respect to the back wall (21),

(27) At least one thrust actuator (51) controls the movement of the first arm (50). Two thrust actuators (51) of hydraulic type are preferably used, being disposed on two opposite sides of the first arm. Each thrust actuator (51) comprises a cylinder (52) connected to the frame (20) of the base of the vehicle and a piston (53) connected to a flange (59) that protrudes in lateral position from the first arm (50).

(28) A second arm (54) is slidingly mounted with respect to the first arm (50), in telescopic coupling mode. Advantageously, the second arm (54) is a male arm that slides inside the first arm, which is a female arm, but, obviously, likewise, the first arm can be a male arm and the second arm can be a female arm.

(29) The second arm (54) can go from an extracted position inside the first arm to an extracted position in which it protrudes in upper position from the first arm, A lifting actuator (7), preferably of hydraulic type, is mounted inside the first arm (50) to control the movement of the second arm (54). The lifting actuator (7) comprises a cylinder (70) connected to the first arm (50) and a piston (71) connected to the second arm (54).

(30) Actuation levers (not shown) are arranged in the back left-hand portion of the base (2) (in safety position with respect to the counterweight (4)). The actuation levers actuate the thrust actuators (51) and the lifting actuator (7).

(31) The second arm (54) has an eccentric shape, i.e. a non-linear shape. The second arm (54) comprises a rearward protruding end portion (6). The end portion (6) is tilted or curved with respect to the longitudinal axis of the second arm that corresponds to the sliding axis of the second arm inside the first arm.

(32) A shaft (56) is mounted in the end portion (6) of the second arm (54), with horizontal axis in parallel position to the plane of the back wall (21).

(33) Connection means (57) are connected to the shaft (56). The connection means (57) of the lifting system (5) preferably comprise two articulated arms, but can also consist in ropes or actuators. Each articulated arm of the connection means (57) comprises a first connecting rod (57a) hinged to the shaft (56) and a second connecting rod (57b) hinged to the first connecting rod (57a).

(34) One end of the second connecting rod (57b) is provided with a pin (58). In this way, the pin (58) of the second connecting rod of the lifting system can be engaged inside the hole (46) of the flanges (45) of the counterweight.

(35) Obviously, a rod can be inserted between the two flanges (45) of the counterweight and the connection means (57) are connected to said rod to lift the counterweight.

(36) With reference to FIG. 11, the end portion (6) is dimensioned in such a way that the distance (e) between the external surface of the first arm (50) and an axis (A) parallel to the axis of the first arm and passing through the axis of the shaft (56) is higher than the distance (e1) between the center of gravity (G) of the counterweight (4) and the front surface (42) of the counterweight. As a matter of fact, when lifting and lowering the counterweight, the axes of the holes (46) of the flanges (45) of the counterweight and the shaft (56) of the end portion (6) of the second arm intersect a vertical axis passing through the center of gravity (G) of the counterweight.

(37) In this way, given that the distance (e) is higher than the distance (e1), the front wall (42) of the counterweight does not interfere with the external surface of the first arm (50).

(38) This description continues illustrating the operation of the lifting system (5).

(39) The counterweight (4) is connected to the articulated arms of the connection means (57) by inserting the pins (58) of the second connecting rods inside the holes (46) of the flanges of the counterweight, when the counterweight is safely positioned on the ground.

(40) Successively, the operator actuates the actuation levers that control the movement of the lifting actuator (7) and of the thrust actuators (51) to lift the counterweight (4). The counterweight (4) is positioned above the brackets (122) by combining the movement of the lifting actuator (7) and of the thrust actuators (51). When the counterweight (4) is above the brackets (122), but not in contact yet with the brackets, the second arm (54) is lowered by closing the lifting actuator (51), thus lowering the counterweight (4).

(41) Before the counterweight (4) comes in contact with the brackets (122), the centering pins (47) of the counterweight are engaged inside the centering housings (123) of the brackets, centering the counterweight with respect to the brackets, without the need for the operator to place himself under the brackets.

(42) When the counterweight (4) is positioned on the brackets (122), but not yet disconnected from the lifting system (5), the fixing screws are inserted under the brackets (122) to fix the counterweight (4) to the brackets (122). Now the lifting actuator (7) is closed completely in such a way to bring the second arm (54) to a retracted position at a lower height than the hood (25) of the vehicle.

(43) The lifting system (5) has the following advantages:

(44) Such a lifting system (5) is completely folded under the hood (25) of the engine in such a way not to increase the height of the public works vehicle (1) when the public works vehicle (1) is in transport configuration.

(45) Such a lifting system (5) uses a standard counterweight (4), just like the counterweights used in excavators; therefore, it is not necessary to make expensive modifications on the counterweight or to obtain a suitable housing on the brackets (122) of the frame of the public works vehicle.

(46) Such a lifting system (5) allows the operator to work in total safety because, when fixing the counterweight to the brackets by means of fixing screws, the counterweight (4) is positioned on the brackets and the lifting system is connected to the counterweight.

(47) Several equivalent variations and modifications can be made to the present embodiments of the invention, which are within the reach of an expert of the field, falling in any case within the scope of the invention.