Crane with a telescopic extension system

Abstract

Crane (10) for lifting and transporting loads, comprising: an arm (18) adapted for handling loads; a telescopic device (18, 22) comprising at least two mutually sliding segments; an anti-friction device (20) comprising: a supporting portion (14) mounted to an exterior segment of the telescopic device (18, 22); a sliding block (30), movably mounted to the supporting portion (14), adapted to press against an interior segment of the telescopic device (18, 22); adjustment means for adjusting the action of the sliding block (30) against the interior segment.

Description

[0001] TITLE: "Crane with a telescopic extension system

[0002] DESCRIPTION

[0003] Technical field

[0004] The present invention relates to a crane or machine for lifting and handling loads, which is provided with telescopic devices, e.g. a telescopic vertical column or a telescopic arm.

[0005] Technical background

[0006] In the manufacturing and craft industry, it is known that loads, even very heavy ones, have to be picked up, moved, and then positioned at considerable heights and distances from the place of pick-up.

[0007] On a crane, it is known to use telescopic devices or systems, e.g. the vertical column or the horizontal arm that carries the load. Such telescopic devices have a plurality of mutually sliding tubes. When loads are heavy, there is considerable friction between the sliding parts of a telescopic device.

[0008] The need is therefore felt for equipping cranes with a system which can limit the friction between telescopic parts, while being also compact, reliable and easy to use. Summary of the invention

[0009] It is one object of the present invention to provide a crane which can overcome this and other drawbacks of the prior art, while at the same time being simple and economical to manufacture.

[0010] According to the present invention, this and other objects are achieved through a crane having the features set out in the appended independent claim.

[0011] It is understood that the appended claims are an integral part of the technical teachings provided in the following detailed description of the present invention. In particular, the appended dependent claims define some preferred embodiments of the present invention that include some optional technical features.

[0012] Brief description of the drawings

[0013] Further features and advantages of the present invention will become apparent in light of the detailed description that follows, provided merely as a non-limiting example with particular reference to the annexed drawings, wherein :

[0014] - Figure 1 is a side view of a crane in accordance with one embodiment of the present invention;

[0015] - Figure 2 is a side view of the vertical column and arm of the crane of Fig. 1;

[0016] - Figures 3a, 3b, 3c are, respectively, a front view, a side view and a top view of a special system for facilitating the mutual sliding of telescopic portions.

[0017] Detailed description of the invention

[0018] With reference to the accompanying drawings, numeral 10 designates as a whole a crane for lifting and handling loads, which comprises:

[0019] - an arm 18 adapted for handling loads;

[0020] - a telescopic device 18, 22 comprising at least two mutually sliding segments;

[0021] - an anti-friction device 20.

[0022] Anti-friction device 20 comprises:

[0023] - a supporting portion 14 mounted to an exterior segment of telescopic device 18, 22,

[0024] - a sliding block 30, mounted movable (in particular, slidable) to supporting portion 14, adapted to press against an interior segment of telescopic device 18, 22,

[0025] - adjustment means for adjusting the action of sliding block 30 against said interior segment.

[0026] Preferably, the adjustment means are configured for adjusting the force exerted by sliding block 30 against the interior segment. As an alternative, the adjustment means are used to adjust the distance between sliding block 30 and supporting portion 14. It is thus possible to adjust the friction and the play between the two mutually sliding segments with which anti-friction device 20 is associated.

[0027] In particular, the crane has a base frame 12 adapted to transfer the loads of crane 10 onto a support surface through means of contact with such surface, such as wheels 34, 35.

[0028] For clarity, the following will describe, without any limitation whatsoever, a crane 10 having a particular structure and a preferred lifting mechanism.

[0029] With particular reference to the variant illustrated in Fig. 1, crane 10 comprises:

[0030] - base frame 12;

[0031] - arm 18, adapted for handling loads, mounted movable relative to base frame 12.

[0032] Conveniently, arm 18 is telescopic and comprises sliding segments controlled by a second linear actuator 26. A first segment 18a is movably constrained to base frame 12, while the at least one other segment is slidable relative to the first segment 18a. The second linear actuator 26 is adapted to perform the operation of extending / retract ing the segments in order to increase / decrease the overhang of arm 18.

[0033] Crane 10 has a telescopic vertical column 22, to which arm 18 is mounted. In particular, the top end of said column 22 is constrained, rigidly in the example shown herein, to the first segment 18a. In the example, a first linear actuator 24 extends vertical column 22. In the example, arm 18 is in a substantially horizontal position.

[0034] Conveniently, one or more linear actuators 24, 26 of crane 10 are hydraulic jacks, e.g. a hydraulic jack with two simultaneous stages.

[0035] Conveniently, one or more linear actuators 24, 26 of crane 10 are linear actuators with simultaneously extending stages, e.g. a hydraulic jack with simultaneous extending stages. In particular, a linear actuator with simultaneously extending stages is an actuator with multiple simultaneous stages, e.g. with two or three stages. In the example, actuators 24 and 26 are actuators with multiple simultaneous stages. One advantage of linear actuators with simultaneously extending stages lies in the fact that, the power being equal, the speed of extension is increased, e.g. tripled. Moreover, the load bearable by the element (arm 18 or column 22) whereon actuator 24 or 26 is installed has a given value at maximum extension: at half extension, the load bearable by such element is twice that at maximum extension.

[0036] Preferably, linear actuators 24, 26 of crane 10, in particular linear actuators with simultaneously extending stages, are co-ordinated by a control system, e.g. a control unit. Therefore, the control system is configured to at least control the operation of such linear actuators 24, 26.

[0037] Optionally, vertical column 22 is rotatable about a vertical axis. In particular, vertical column 22 may be mounted on an upper structure actuated by a respective motor 27.

[0038] Preferably, arm 18 is provided with means for grabbing and transporting loads, such as, for example, a grab, a grapple, a hook, a platform, etc.

[0039] In the example illustrated herein, a windlass system or winch 28 is associated with arm 18 for handling the loads. Such winch 28 is conveniently operated by motor means, e.g. an electric motor. A hook or the like, associated with windlass (or winch) 28, can be extended or retracted under the action of the winch.

[0040] Preferably, crane 10 comprises a means for transmitting traction to the ground. The means for transmitting traction to the ground may comprise a drive wheel 34, or a track, or any other means suitable for transmitting motive force to a support surface. For example, crane 10 comprises a pair of drive wheels 34, optionally capable of steering. Therefore, for example, two of wheels 34, 35 are drive wheels 34.

[0041] According to a preferred embodiment of the present invention, crane 10 comprises a wireless remote control system, adapted to control the motion of arm 18 and / or of drive wheel 34 and / or of column 22. The control system may include, without limitation, a CPU, a PLC, a control unit, etc. The control system may also be configured to execute further functions of crane 10, not listed herein for brevity' s sake.

[0042] Anti-friction device 20 makes it possible to reduce the friction between the two mutually sliding parts, in contact with each other, of the telescopic device, due to the presence of sliding block 30. Sliding block 30 is, in fact, made of a material capable of reducing the friction between the two mutually sliding parts of the telescopic device. Device 20 also reduces or eliminates the play between such two mutually sliding parts, and offers the possibility of adjusting such play. It is thus advantageously possible to find a trade-off between low friction (when sliding block 30 exerts little force on the segment) and reduced play between the two sliding parts (when sliding block 30 exerts a great force on the segment) . The invention allows the user to adjust the action of sliding block 30 according to the user' s preferences, the type of load to be borne by crane 10, or the wear of the components of the telescopic device; for example, the wear undergone by sliding block 30 over time can be compensated for by acting upon the adjustment means in such a way as to keep the friction and play between the parts within desired ranges. In addition, due to such adjustability, anti-friction device 20 can be installed on different types of machines or cranes requiring considerably different tolerances for the telescopic device and intended to handle very different loads, in order to always keep the functionality of the telescopic device at an optimal level.

[0043] Preferably, the anti-friction device comprises an elastic means 33 for pushing sliding block 30 against the interior segment. In particular, elastic means 33 is a spring, preferably a coil spring. Elastic means 33 keeps sliding block 30 pressed against the interior segment.

[0044] Preferably, the adjustment means comprise one or more screws 32. In the example, there are several screws 32, in particular five screws 32. In particular, screw 32 (in the example, screws 32) is engaged in a thread integral with supporting portion 14. In more detail, screws 32 are parallel to one another. In the example, screws 32 are aligned along a straight line, in particular perpendicular to the axis along which the telescopic segments slide. In the example, screws 32 associated with column 22 are aligned horizontally in each anti-friction device 20.

[0045] In the example, screw 32 is coupled to elastic means 34, and elastic means 33 acts upon sliding block 30. In particular, elastic means 33 is interposed between sliding block 30 and screw 32. In the example, one end of elastic means 34 is mounted to screw 32, and the other end of elastic means 34 is mounted to sliding block 30. In more detail, elastic means 33 is mounted to an end of the shank of screw 32. In particular, in anti-friction device 20 there are a plurality of screws 32 and a plurality of elastic means 33, and each screw 32 is coupled to a respective elastic means 33. In the example shown herein, elastic means 33 is a coil spring whose longitudinal axis is aligned with the longitudinal axis of screw 32 to which it is mounted. When screw 32 is screwed or unscrewed, screw 32 will move relative to supporting portion 14, and hence relative to the interior segment of the telescopic device. This will affect the action exerted on the segment by sliding block 30. In the example, by adjusting screw 32 it is possible to displace elastic means 33 relative to supporting portion 14, and hence relative to the interior segment, thus varying the force exerted on the segment by sliding block 30.

[0046] Sliding block 30 has a face 36 adapted to abut against the interior segment. For example, face 36 matches the shape of the segment it must act upon. For example, face 36 is flat, but may alternatively be curved.

[0047] In particular, supporting portion 14 has a cavity 38 in which sliding block 30 is at least partially housed and in which the latter can slide. Sliding block 30 is configured to protrude from cavity 38 to abut against the respective segment of the telescopic device. In the example, sliding block 30 has a parallelepiped shape.

[0048] Cavity 38 also serves to guide the movement of sliding block 30.

[0049] Sliding block 30, or a part thereof adapted to press against the interior segment, may be made of polymeric material, e.g. nylon, but further alternatives are also possible, e.g. teflon. Sliding block 30 may also be made of non-polymeric material, e.g. metal.

[0050] In the particular example illustrated herein, the telescopic device is a vertical column 22, and antifriction device 20 is associated with said vertical column 22. Crane 10 shown in the drawings also has another telescopic device, i.e. telescopic arm 18. Therefore, the crane may comprise one or more telescopic devices, and one or more anti-friction devices 20 may be associated with one or more of such telescopic devices. Preferably, the at least one anti-friction device 20 is mounted to a telescopic device adapted for moving the load, e.g. column 22 and / or arm 18.

[0051] The interior segment is configured to slide within the exterior segment. As is known, in a telescopic device, e.g. column 22, there may be more than two sliding segments; therefore, a given segment may be interior to a bigger segment exterior thereto, and may at the same time be exterior to a smaller segment interior thereto.

[0052] Preferably, a telescopic device, e.g. column 2, comprises a plurality of anti-friction devices 20. In this way, the advantages offered by device 20 can be achieved for all sliding segments. In particular, in column 22 illustrated herein there are three anti-friction devices 20. When a telescopic device has three or more segments, there are several areas where a segment slides relative to another one, and anti-friction device 20 is arranged in those very areas. By way of non-limiting example, if a telescopic device has n mutually sliding segments, n-1 anti-friction devices 20 are installed on such telescopic device .

[0053] In the example, column 22 has four segments A, B, C, D and comprises three anti-friction devices 20. Segment A is fixedly mounted vertical on base frame 12, while the other segments B, C, D are extensible and movable relative to frame base 12. A first anti-friction device 20 is mounted to segment A and acts upon segment B, a second antifriction device 20 is mounted to segment B and acts upon segment C, and a third anti-friction device 20 is mounted to segment C and acts upon segment D. Thus, for example, segment C is interior to segment B, but exterior to segment D. For example, supporting portion 14 of first antifriction device 20 is mounted to segment A, and sliding block 30 of that anti-friction device 20 acts upon segment B.

[0054] Conveniently, the adjustment means are accessible to a user from outside the telescopic device. It is not necessary, therefore, to dismount parts of crane 10 or of the telescopic device to operate said device 20, e.g. in order to make an adjustment. In more detail, the one or more screws 32, and particularly the screw heads, are accessible from the outside.

[0055] Crane 10 preferably comprises at least one electric battery, which may be either rechargeable or not. Conveniently, the battery is a rechargeable one, and can be recharged, without removing it from the crane, through suitable battery charging means, e.g. by connecting the charging means to an industrial or domestic electric socket .

[0056] The battery is adapted to supply the energy necessary for the execution of one or more of the following operations: operating linear actuators 26; operating signalling devices, including acoustic and visual ones; supplying power to the control system; operating the means for transmitting traction to the ground (e.g. the drive wheel 34 ) ; etc .

[0057] With reference to the particular crane 10 illustrated herein, arm 18 is substantially perpendicular to vertical column 22. In particular, arm 18 and column 22 are rigidly mounted perpendicular to each other. Preferably, vertical column 22 is substantially vertical, and the arm is substantially horizontal. These "horizontal / vertical" definitions refer to a condition in which crane 10 is resting on a horizontal flat surface. Arm 18 and vertical column 22 are telescopic. Therefore, they 18, 22 are movable along two mutually perpendicular Cartesian axes. Preferably, vertical column 22 is rotatable about its own longitudinal axis, i.e. about a substantially vertical axis. Motor 27 provides such rotation. The fact that arm 18 and vertical column 22 are perpendicular to each other makes it advantageously possible to achieve considerable overhang and high load elevation, with a clear area under arm 18. Thus, the load can be moved far in narrow spaces, e.g. inside a factory or a warehouse, without the need for modifying the environment where crane 10 will have to operate. This makes crane 10 particularly suitable for work in indoor environments. Furthermore, crane 10 is quite compact .

[0058] Preferably, crane 10 comprises three sensors (in particular, three encoders) for detecting, respectively, the elongation of telescopic arm 18, the elongation of telescopic vertical column 22, and the angular position of vertical column 22. The control unit of crane 10 is configured for receiving signals from said three sensors and for controlling, as a function of such signals, the elongation of arm 18, the elongation of vertical column 22, and a rotation of vertical column 22 about its vertical axis. In the example, the three above-mentioned movements are controlled independently by the control unit. In particular, the control unit controls the operation of the respective actuators or motors 24, 26, 27. This results in very precise handling of the load.

[0059] A further advantage of the invention lies in the fact that sliding block 30, by reducing the play, reduces also the resulting oscillations during the rotation of vertical column 22 about its vertical axis. During such rotation, in fact, great forces act upon the sliding segments of vertical column 22, due to load inertia and lever arm. In general, anti-friction device 20 makes it possible to handle the load in a very precise manner, with very low friction .

[0060] Anti-friction device 20 of the present invention can be incorporated into many other types of cranes having much different lifting mechanisms.

[0061] Of course, without prejudice to the principle of the invention, the forms of embodiment and the implementation details may be extensively varied from those described and illustrated herein by way of non-limiting example, without however departing from the scope of the invention as set out in the appended claims.

[0062] Barzand & Zanardo Milano S.p.A. 

[0063] Legend : segments of the vertical column A, B, C, D crane 10 base frame 12 supporting portion 14 bracket 15 abutment portion 16 arm 18 first segment of the arm 18a anti-friction device 20 telescopic vertical column 22 first linear actuator 24 second linear actuator 26 motor 27 winch 28 sliding block 30 screw 32 elastic means 33 drive wheel 34 wheel 35 face 36 cavity 38

[0064] Barzand & Zanardo Milano S.p.A.

Claims

CLAIMS1. Crane (10) for lifting and transporting loads, comprising :- an arm (18) adapted for handling loads;- a telescopic device (18, 22) comprising at least two mutually sliding segments;- an anti-friction device (20) , comprising:- a supporting portion (14) mounted to an exterior segment of the telescopic device (18, 22) ,- a sliding block (30) , movably mounted to the supporting portion (14) , adapted to press against an interior segment of the telescopic device (18, 22) ,- adjustment means for adjusting the action of the sliding block (30) against the interior segment.

2. Crane (10) according to claim 1, wherein the adjustment means are configured to adjust the force applied against the interior segment by the sliding block (30) .

3. Crane (10) according to claim 2, wherein the antifriction device (20) comprises an elastic means (33) for pushing the sliding block (30) against the interior segment .

4. Crane (10) according to claim 1 or 2 or 3, wherein the adjustment means comprise one or more screws (32) .

5. Crane (10) according to any one of the preceding claims, wherein the telescopic device (18, 22) is a vertical column (22) , and the anti-friction device (20) is associated with said vertical column (22) .

6. Crane (10) according to any one of the preceding claims, wherein the interior segment is configured to slide within the exterior segment.

7. Crane (10) according to claims 3 and 4, wherein the screw (32) is coupled to the elastic means (33) , and theelastic means (33) acts upon the sliding block (30) .

8. Crane (10) according to claim 7, wherein there are a plurality of screws (32) and elastic means (33) , and each screw (32) is coupled to the respective elastic means (33) .

9. Crane (10) according to claim 5 or 7 or 8, wherein the screw (32) is engaged into a thread integral with the supporting portion (14) .

10. Crane (10) according to any one of the preceding claims, wherein the adjustment means are accessible to a user from outside the telescopic device.

11. Crane (10) according to any one of the preceding claims, wherein a telescopic device comprises a plurality of anti-friction devices (20) .

12. Crane (10) according to any one of the preceding claims, wherein the arm (18) is substantially perpendicular to the vertical column (22) , and the vertical column (22) is rotatable about a substantially vertical axis; wherein the arm (18) and the vertical column (22) are telescopic; wherein the crane (10) comprises: three sensors for detecting, respectively, an elongation of the telescopic arm (18) , an elongation of the telescopic vertical column (22) , and an angular position of the vertical column (22) ; a control unit configured for receiving signals from said three sensors and for controlling, as a function of such signals, the elongation of the arm (18) , the elongation of the vertical column (22) , and a rotation of the vertical column (22) about its vertical axis.

13. Crane (10) according to any one of the preceding claims, comprising a telescopic vertical column (22) , to which the arm (18) is mounted; wherein:- a first linear actuator (24) is adapted to extend thevertical column (22) ,- the arm (18) is telescopic and comprises sliding segments adapted to be controlled by a second linear actuator (26) , - one or more linear actuators (24, 26) of the crane(10) are linear actuators with simultaneously extending stages .Barzand & Zanardo Milano S.p.A. / LT

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