Crane with a system for limiting the pull of the winch

Abstract

Crane (10) for lifting and transporting loads, comprising: a base frame (12) adapted to transfer the loads of the crane (10) onto a support surface through means of contact with such surface, such as wheels (34); and an arm (18) adapted for moving the loads, wherein a winch (28) is associated with the arm (18) for winding and unwinding a cable (32). There is a system for limiting the pull of the winch (28), comprising : a support portion (14) mounted rotatable about an axis of rotation to the arm (18), wherein the winch (28) is mounted to the support portion (14); an abutment portion (16) integral with the arm (18); an elastic means configured to counter the rotation of the support portion (14) relative to the abutment portion (16) when the winch (28) is supporting a load; a sensor for detecting the mutual position of the abutment portion (16) and support portion (14); and a control system for executing predetermined functions of the crane (10) when such mutual position reaches a threshold condition.

Description

[0001] TITLE : "Crane with a system for limiting the pull of the winch"

[0002] DESCRIPTION

[0003] Technical field

[0004] The present invention relates to a crane , or machine , for li fting and moving loads , equipped with a winch .

[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] Cranes are commonly used, which are provided with an arm whereon a winch is mounted to wind and unwind a cable . The cable has a hook, which is used for li fting loads .

[0008] However, there is a risk that said crane might tip over, resulting in danger for any people and wares nearby . There is also a risk that the winch system might get damaged, i f the associated load is too heavy .

[0009] The need is therefore felt for cranes , to be used for li fting and moving loads , equipped with an anti-rollover system also useful to prevent winch damage .

[0010] Summary of the invention

[0011] It is one obj ect 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 .

[0012] In particular, one of the technical problems solved by the present invention is providing a crane for li fting and moving loads which is equipped with a system for limiting the pull of the winch .

[0013] According to the present invention, this and other obj ects are achieved through a crane having the features set out in the appended independent claim .

[0014] 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 .

[0015] Brief description of the drawings

[0016] 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 :

[0017] Figure 1 is a side view of a crane in accordance with one embodiment of the present invention;

[0018] Figure 2 is a s ide view of the end of the crane arm to which the winch is mounted, in accordance with one embodiment of the present invention;

[0019] Figure 3 is a front view o f Figure 2 , wherein the winch is not shown;

[0020] Figure 4 is a plan view of Figure 3 ;

[0021] Figure 5a is a front view of a detail of the crane ;

[0022] Figure 5b is a plan view of the detail shown in Figure 5a .

[0023] Detailed description of the invention

[0024] With reference to the accompanying drawings , numeral 10 designates as a whole a crane for li fting and moving loads , which comprises : a base frame 12 adapted to trans fer the loads of crane 10 onto a support surface through means of contact with such surface , such as wheels 34 ; an arm 18 adapted for moving the loads , wherein a winch 28 is associated with arm 18 for winding and unwinding a cable 32 .

[0025] Crane 10 includes a system for limiting the pull o f the winch, comprising : a support portion 14 mounted to arm 18 rotatable about an axis of rotation, wherein winch 28 is mounted to support portion 14 ; an abutment portion 16 integral with arm 18 ; an elastic means configured to counter the rotation of support portion 14 relative to abutment portion 16 when winch 28 is supporting a load; a sensor for detecting the mutual position of abutment portion 16 and support portion 14 , a control system for executing predetermined functions of crane 10 when such mutual position reaches a threshold condition .

[0026] For clarity, the following will describe , without any limitation whatsoever, a crane 10 having a particular structure and a preferred li fting mechanism .

[0027] With particular reference to the variant illustrated in Fig . 1 , crane 10 comprises : base frame 12 ; arm 18 , adapted for moving the loads , mounted movable relative to base frame 12 .

[0028] In particular, the crane includes a pair of connecting members 22 , each connecting member 22 being hinged to base frame 12 and to arm 18 , so as to create an articulated quadrilateral . There is a first linear actuator 24 mounted to base frame 12 and hinged to arm 18 , providing the elevation motion of arm 18 . By way of non-limiting example , Figure 1 shows an articulated quadrilateral defined by the points identified by letters A, B, C, D.

[0029] In particular, base frame 12 has a pair of brackets 15, in particular arranged vertically. To each bracket 15, a respective pair of connecting members 22 are hinged. Thus, there are two pairs of connecting members 22, arranged substantially on both sides of arm 18.

[0030] 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 extracting / retracting the segments in order to increase / decrease the overhang of arm 18. The upper end of the first linear actuator 24 is hinged to the first segment 18a. Conveniently, linear actuators 24, 26, or at least one of them, are hydraulic cylinders. Conveniently, at least one of linear actuators 24, 26 is a two-stage double-acting hydraulic cylinder. Connecting members 22 are hinged to the first segment 18a. In the example, brackets 15 are fixed (e.g. welded) to support columns 47 integral with base frame 12. Therefore, in order to rotate arm 18 in a plan view, it is necessary to rotate crane 10 on the ground by steering wheels 34.

[0031] Conveniently, arm 18 is telescopic.

[0032] 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.

[0033] A windlass system or winch is associated with arm 18 in order to move the loads. Such winch is conveniently operated by motor means, e.g. an electric motor.

[0034] A hook, or the like, associated with the windlass (or winch) can be extracted or retracted under the action o f the winch .

[0035] In accordance with a variant embodiment not illustrated herein, arm 18 comprises a pair of hooks : the first hook is controlled by a winch, and is there fore movable , or extractable, relative to arm 18 ; the second hook is , on the contrary, f ixed relative to arm 18 . In particular, the first and second hooks can be located at the distal end of the telescopic segment of arm 18 .

[0036] According to further variant embodiments , only one or more fixed hooks can be associated with arm 18 . Moreover, the point shown in the following examples where the hooks , whether fixed or extractable , are associated with arm 18 should not be understood in a l imiting sense . For example , the fixed hook may be fastened to the first or second segment , thus not being located at the distal end of arm 18 . Furthermore , the at least one hook may also be associated with a non-telescopic arm 18 .

[0037] 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 , 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 , conveniently capable of steering . Therefore , for example , two of wheels 34 are drive wheels .

[0038] 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 the motion of the drive wheels .

[0039] Preferably, there is a load or force sensor 20 which includes the elastic means and the first sensor . Load or force sensor 20 is mounted to abutment portion 16 and / or to support portion 14. In particular, load sensor 20 is a load cell, more specifically a pin-type load cell. For brevity's sake, reference will be made below to load sensor 20. In the illustrated variant, load sensor 20 is mounted to abutment portion 16.

[0040] With reference to the drawings, when arm 18 is substantially horizontal, the axis of rotation of support portion 14 is in a higher position than (i.e. in an elevated position relative to) the elastic means and the first sensor. Thus, the axis of rotation of support portion 14 is higher than load sensor 20. In Fig. 2, said axis of rotation is close to the upper end of abutment portion 16, and load sensor 20 is close to the lower end of abutment portion 16. In particular, the axis of rotation of support portion 14 is horizontal. A pin-type connection 42 defines the axis of rotation of support portion 14 relative to arm 18, and hence relative to abutment portion 16. Pin-type connection 42 shown in the example permits rotations only to occur between the connected parts.

[0041] In the example, abutment portion 16 is a plate. Abutment portion 16 is located at one end of arm 18, in particular at one end of a telescopic part of arm 18. Abutment portion 16 can be mounted to arm 18 by means of removable fasteners (e.g. bolts) , or else it may be welded to arm 18 or made as one piece with it 18. In the example, the plate of abutment portion 16 is perpendicular to the longitudinal axis of arm 18.

[0042] In the example, load sensor 20 is mounted to abutment portion 16 by means of two brackets 36, which, in particular, are mounted perpendicular (e.g. by welding) to abutment portion 16. In the embodiment illustrated herein, support portion 14 comprises: a support plate 38 whereon winch 28 is mounted, a main plate 40 to which the support plate is fixed 38, and two rods 44 to which main plate 40 is fixed. In the example, support plate 38 is mounted to main plate 40 by means of bolts 52; rods 44 are mounted to main plate 40 by welding. Elements 38, 40, 44 are integral with each other. In the example, the axis of rotation between portions 14, 16 is parallel to the plate of abutment portion 16 and to main plate 40. In particular, the plate of abutment portion 16 and main plate 40 can assume a configuration in which they are parallel to each other (Fig. 1) . Rods 44 are hinged to abutment portion 16 through pin-type connection 42.

[0043] In the example, abutment portion 16 comprises brackets 54 (in the example, four brackets 54) integral with one another 16. Such brackets 54 and rods 44 have holes adapted to be crossed by a pin to create pin-type connection 42. In particular, brackets 54 are mounted perpendicular (e.g. by welding) to abutment portion 16. In more detail, brackets 16, 54 are arranged on two opposite faces of abutment portion 16 (which is substantially flat in the example) .

[0044] Support portion 14 comprises a protrusion 56 adapted to abut against load sensor 20. In the preferred embodiment, protrusion 56 is located at a lower end of support portion 14. In more detail, protrusion 56 is mounted to rods 44 at one end (the lower one in the example) of such rods 44.

[0045] Protrusion 56 shown in the example is a connecting rod, in particular having two holes 58, 59 at its ends. Protrusion 56 has a hole 59 which is crossed by load sensor 20. Protrusion 56 has another hole 58 which is used for mounting the connecting rod to rods 44 through a pin 60. In particular, protrusion 56 has a tubular portion 62 that defines hole 59. Tubular portion 62 projects transversally from protrusion 56.

[0046] Protrusion 56 is interposed between the two brackets 36 to which load sensor 20 is mounted, and can slide relative to such brackets 36, particularly in a direction parallel to such brackets 36. In general, protrusion 56 is constrained to support portion 14 and is movable relative to abutment portion 16.

[0047] With reference to Fig. 2, when a load pulls cable 32 downwards, this results in a clockwise rotation of support portion 14. The elastic means, which in the example is included in load sensor 20, counters such rotation. During this clockwise rotation, protrusion 56 moves leftwards, and the elastic means counters such leftward movement. The heavier the load, the greater the extent of the (clockwise in Fig. 2) rotation of support portion 14 relative to abutment portion 16. The heavier the load, the greater the force exerted by abutment portion 16 on the elastic means, particularly on load sensor 20. Support portion 14 generates a force on the elastic means, particularly on load sensor 20, which is proportional to the load borne by winch 28. This makes it possible to easily and reliably detect any load variation. Such detection may be useful to prevent crane 10 from tipping over, or to prevent damage to winch 28 and cable 32, which might occur due to excessive load .

[0048] Protrusion 56 generates a force on load sensor 20 which is proportional to the load borne by winch 28. In the example, protrusion 56 can be made to slide relative to abutment portion 16, more particularly relative to brackets 36, through the effect of the load borne by winch 28. In Fig. 2, an upward-pointing arrow indicates the direction in which protrusion 56 moves as the load on winch 28 increases. Load sensor 20 detects the value of the force being exerted by protrusion 56. The illustrated load sensor 20 is a pin-type load cell, arranged along an axis (horizontal in Fig. 2) which is perpendicular to the direction of movement of protrusion 56.

[0049] With reference to other possible variant embodiments, the elastic means, conveniently consisting of a spring, is mounted to either support portion 14 (e.g. to main plate 40) or abutment portion 16, and there is a sensor associated with either one of such portions 14, 16 which is adapted to detect the proximity or contact of the other portion 16, 14. The sensor is, preferably, a contact sensor or a proximity sensor (e.g. a photocell or a capacitive, inductive, magnetic, ultrasonic, optical, etc. sensor) .

[0050] The control system may include, without any limitation whatsoever, a CPU, a PLC, a control unit, etc. The control system may be located near that end of arm 18 which is proximal to winch 28, or in another region of crane 10.

[0051] In general, when the mutual position of support portion 14 and abutment portion 16 reaches a threshold condition, or a threshold value, the control system can be configured to execute numerous different predetermined functions, including for example: stopping one or more linear actuators 24, 26; executing one or more predetermined movements of at least one linear actuator 24, 26; interrupting the operation of the drive wheel; interrupting the movement of winch 28; emitting an emergency signal perceivable by a user (e.g. an audible and / or luminous signal) , etc. In general , it is possible to configure the control system to interrupt or inhibit , when the mutual position of such portions 14 , 16 reaches a threshold value , any movement of crane 10 which might cause the rolling torque to increase . The control system may also be configured to execute , when the mutual position of such portions 14 , 16 reaches a threshold value , one or more movements of crane 10 which will cause the rolling torque to decrease .

[0052] According to some possible embodiments , the control system is configured to execute some predetermined functions depending on the mutual position of support portion 14 and abutment portion 16 as well as on the position of arm 18 , which in such a case will be rotatable relative to base frame 12 ( in particular, about a vertical axis ) . With reference to a plan view, crane 10 may have a higher rolling torque when arm 18 is in a first angular position, and a higher rolling torque when arm 18 is in another angular position . Therefore , the rollover condition may vary depending on the angular position of arm 18 . Optionally, when a telescopic arm is used, the control system will also take into account the elongation of arm

[0053] 18 . In fact , the greater the elongation of telescopic arm

[0054] 19 , the smaller the maximum load that arm 18 will be able to withstand without tipping over .

[0055] Therefore , the system for limiting the pull o f the winch according to the invention makes it possible to prevent damage to winch 28 , and is also useful to sense the load in order to prevent the crane from rolling over . The system of the invention is both simple and reliable .

[0056] 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 .

[0057] The battery is adapted to supply the energy necessary for the execution of one or more of the following operations: operating linear actuators 24, 26; operating the signalling devices, including acoustic and visual ones; supplying power to the control system; operating the means for transmitting traction to the ground (e.g. drive wheel 34 ) ; etc .

[0058] The system for limiting the pull of the winch according to the present invention can be incorporated into many other types of cranes having much different lifting mechanisms .

[0059] 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 .

[0060] Barzand & Zanardo Milano S.p.A.

[0061] Legend : crane 10 base frame 12 support portion 14 bracket 15 abutment portion 16 arm 18 first segment of the arm 18a load sensor 20 connecting member 22 first linear actuator 24 second linear actuator 26 winch 28 cable 32 wheels 34 bracket 36 support plate 38 main plate 40 pin-type connection 42 rods 44 support column 47 bracket 54 protrusion 56 holes 58 , 59 pin 60 tubular portion 62

[0062] Barzand & Zanardo Milano S . p .A.

Claims

CLAIMS1. Crane (10) for lifting and transporting loads, comprising : a base frame (12) adapted to transfer the loads of the crane (10) onto a support surface through means of contact with such surface, such as wheels (34) ; an arm (18) adapted for moving the loads, wherein a winch (28) is associated with the arm (18) for winding and unwinding a cable (32) ; characterized in that it has a system for limiting the pull of the winch (28) , comprising: a support portion (14) mounted rotatable about an axis of rotation to the arm (18) , wherein the winch (28) is mounted to the support portion (14) ; an abutment portion (16) integral with the arm (18) ; an elastic means configured to counter the rotation of the support portion (14) relative to the abutment portion (16) when the winch (28) is supporting a load; a sensor for detecting the mutual position of the abutment portion (16) and support portion (14) , a control system for executing predetermined functions of the crane (10) when such mutual position reaches a threshold condition.

2. Crane (10) according to claim 1, comprising a load or force sensor (20) including the elastic means and the sensor; said load or force sensor (20) being mounted to the abutment portion (16) and / or to the support portion (14) .

3. Crane (10) according to claim 1 or 2, wherein, when the arm (18) is substantially horizontal, the axis of rotation of the support portion (14) is in a higher position than the elastic means and the sensor.

4. Crane (10) according to any one of the precedingclaims, wherein the axis of rotation of the support portion (14) is horizontal.

5. Crane (10) according to any one of the preceding claims, wherein the support portion (14) comprises: a support plate (38) whereon the winch (28) is mounted, a main plate (40) to which the support plate (38) is fixed, and two rods (44) to which the main plate (40) is fixed; wherein the rods (44) are hinged to the abutment portion (16) through a pin-type connection (42) that defines the axis of rotation.

6. Crane (10) according to claim 2, wherein the support portion (14) comprises a protrusion (56) adapted to abut against the load sensor (20) , such load sensor (20) being mounted to the abutment portion (16) ; wherein the protrusion (56) is configured to generate on the load sensor (20) a force that is proportional to the load borne by the winch (28) .

7. Crane (10) according to claim 6, wherein the protrusion (56) has a hole (59) that is crossed by the load sensor (20) .

8. Crane (10) according to claim 2 or 6 or 7, wherein the load sensor (20) is a pin-type load cell.

9. Crane (10) according to any one of the preceding claims, wherein the control system is configured to execute predetermined functions depending on the mutual position of the support portion (14) and abutment portion (16) , and on the position of the arm (18) , which is rotatable about a vertical axis relative to the base frame (12) .

10. Crane (10) according to claim 9, wherein the control system is configured to execute the predetermined functions also depending on the elongation of the arm (18) , which is a telescopic arm.

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