Hub limit switch weight and crane with such a

Abstract

Lift limit switch weight (10) for a crane (1) with two molded parts (11, 12) pivotably connected to each other about a pivot axis (14), which in a closed position together form a passage (16) for receiving a lifting cable (7), wherein the molded parts (11, 12) are designed such that the center of gravity (50) of the lift limit switch weight (10) is spaced apart in the closed position from a longitudinal axis (15) running centrally along the passage (16), characterized in that the pivot axis (14) is offset laterally to a median plane (48) of the lift limit switch weight (10) running through the longitudinal axis (15) and the center of gravity (50).

Description

[0001] The present invention relates to a lifting limit switch weight according to the preamble of claim 1, as well as a lifting limit switch arrangement and a crane with such a weight.

[0002] In cranes, loads are attached to a lifting mast and lifted via a hoist cable, which can be raised or lowered by operating a winch. Depending on the crane type, the hoist cable is guided differently over one or more guide elements. For example, mobile cranes with telescopic booms typically have a boom head with one or more pulleys over which the hoist cable is guided at the free end of the boom.

[0003] During the hoisting process, it must be ensured that the lifting height of the hoisting rope is limited so that the lifting device attached to the hoisting rope (typically a crane hook or hook block) does not collide with the guide device (e.g., the pulleys of a boom head). Pulling the hoisting rope beyond the maximum permissible lifting height would damage the guide device, the boom itself, or even cause the hoisting rope or the lifting device to break, consequently leading to the lifting load falling. To prevent this, the actual lifting height of the hoisting rope, the lifting device, or the load must be continuously monitored and communicated, for example, to a crane control system.

[0004] To monitor the lifting height, limit switches are typically used. These switches have a sensor that detects movement or when the lifting element exceeds a defined maximum height, automatically stopping further retraction of the lifting cable via the winch. A known method involves connecting a limit switch weight to a sensor via a coupling device and guiding it longitudinally along the lifting cable. If the lifting element is raised too far, it strikes the limit switch weight from below, lifting it. This relieves the coupling device of the limit switch, which is registered by the sensor.

[0005] Current technology includes limit switch weights consisting of several individual parts that must be assembled on the lifting cable during installation. However, assembly is time-consuming and cumbersome due to the relatively large mass of the limit switch weight. Alternatively, there are solutions where the limit switch weight has two pivoting hinged sections that can be placed around the lifting cable and connected to each other. However, with prolonged use, this design could lead to wear or damage to the hinge from the lifting cable.

[0006] A generic limit switch weight is known from CN 1 02 295 238 A.

[0007] The present invention therefore aims to provide a lifting limit switch weight that is easy to mount and designed in such a way as to avoid wear or damage to the lifting limit switch weight and the lifting cable.

[0008] According to the invention, this problem is solved by a device having the features of claim 1. Advantageous embodiments of the invention are described in the dependent claims and the following description.

[0009] Accordingly, a limit switch weight is proposed, comprising two molded parts that are articulated, i.e., pivotable about a pivot axis. The molded parts are designed such that, in a closed position, they together form an opening for receiving a lifting cable. The opening is defined by both molded parts. In the assembled state, the lifting cable thus runs through the opening and is enclosed by the limit switch weight.

[0010] According to the invention, the molded parts are designed such that the center of gravity of the limit switch weight is spaced away from the longitudinal axis of the opening for the limit switch weight in the closed position. The latter is defined such that it runs centrally along the opening (i.e., parallel to the lifting cable when the lifting cable is straight and the limit switch weight is not tilted relative to the lifting cable). This allows the limit switch weight to be suspended from a coupling element via a single suspension point without excessive tilting. The suspension point is positioned above the center of gravity. This enables a simple and compact design for the limit switch weight. To achieve such a center of gravity, the limit switch weight can have a greater mass on one side of the opening than on the opposite side.

[0011] According to the invention, the molded parts are further designed such that the pivot axis is offset laterally from a central plane of the limit switch weight that runs through the longitudinal axis and the center of gravity. The pivot axis is therefore not located centrally in a plane with the center of gravity and the longitudinal axis. This eccentric arrangement of the pivot axis protects it from damage to the lifting cable, since tilting of the limit switch weight relative to the lifting cable occurs within the central plane due to the position of the center of gravity, and the pivot axis lies outside this central plane. With a centrally located pivot axis, tilting of the limit switch weight could cause the lifting cable to collide with the joint area of ​​the molded parts, potentially causing damage over time.

[0012] The molded parts can, in principle, be of any design, preferably having a different or asymmetrical structure. Preferably, the molded parts are solid castings to provide the necessary weight for the limit switch assembly. The molded parts can optionally have recesses to selectively influence the weight distribution or the position of the center of gravity.

[0013] The molded parts, together with the pivot axis, preferably form a cohesive assembly with permanently connected components. This eliminates the need to handle multiple individual parts, simplifying assembly and disassembly.

[0014] The pivot axis is preferably formed by a bolt that, in particular, does not protrude beyond the outer contours of the molded parts. This protects it from damage or wear caused by the lifting cable.

[0015] In one possible embodiment, the center of gravity of the limit switch weight is located outside the opening when the switch is in the closed position. In the installed state, the limit switch weight therefore has a greater mass or size on one side of the lifting cable than on the opposite side. The side with the smaller mass can, in the installed state, face additional branch strands of the lifting cable, which, for example, may be sheared multiple times between a hook block and a pulley head. The center of gravity is preferably located below a suspension point of the limit switch weight, so that the longitudinal axis or the opening runs vertically in the suspended state without an external force (such as a force exerted by the lifting cable).

[0016] In another possible embodiment, the molded parts have contact surfaces that, in the closed position, face each other and form a gap between the opening and an outer surface of the limit switch weight. When the molded parts are pivoted apart, the limit switch weight opens and the contact surfaces move away from each other, allowing the lifting cable to be inserted or removed in the open position. By pivoting the molded parts together, the limit switch weight closes and the contact surfaces move towards each other until they are in contact and the lifting cable is completely enclosed by the molded parts.

[0017] The contact surfaces preferably have radial curves and / or edges extending from the longitudinal axis, forming a labyrinthine gap in the closed position. Compared to flat contact surfaces, this offers the advantage that the lifting cable cannot become trapped in the gap. If the molded parts pivot slightly apart during operation, the labyrinthine design of the opening area of ​​the limit switch weight prevents the lifting cable, or any secondary strand of the lifting cable adjacent to the outer edge of the limit switch weight, from becoming unintentionally trapped. Preferably, the opening gap runs obliquely (as a whole labyrinth) to the aforementioned central plane in the closed position.

[0018] In another possible embodiment, the contact surfaces each have at least one right-angled step, preferably at least two right-angled steps, which interlock or lie on top of each other in a step-like fashion when closed. This at least one step forms a barrier for the lifting cable, preventing it from penetrating or becoming trapped in the opening gap. The lengths of the walls forming the step(s) must be selected accordingly, depending on the shape and size of the lifting limit switch weight.

[0019] In another possible embodiment, the gap is located on the side of the opening opposite the pivot axis when the device is closed. Alternatively or additionally, when the device is closed, the center of gravity of the limit switch weight can be located in the area of ​​the gap, or the gap can pass through the center of gravity.

[0020] In another possible embodiment, the molded parts are shaped differently, meaning they do not have an identical or mutually symmetrical structure. Alternatively or additionally, the molded parts can be designed such that the opening has a cross-section that deviates from a circular shape, and in particular, is not symmetrical to the central plane. This can result from the pivot axis being eccentric and the gap being labyrinthine, with the latter not running parallel to the central plane.

[0021] In another possible embodiment, the lifting limit switch weight, in its closed position, has a greater extent along its longitudinal axis (referred to here as length) than across its longitudinal axis (referred to here as width). The lifting limit switch weight can have a generally cuboid shape, although other shapes are also conceivable. Due to its greater length compared to its width, the lifting limit switch weight occupies less space next to the lifting cable, thus reducing, for example, the risk of collision with a secondary strand of the lifting cable. The lifting limit switch weight can be at least twice as long as it is wide, with the aforementioned width referring to an extent across the central plane.

[0022] Preferably, the limit switch weight is wider along the central plane than perpendicular to the central plane when in the closed position. This allows for a weight distribution in which the center of gravity of the limit switch weight lies next to the opening and preferably in the region of the central plane.

[0023] In another possible embodiment, the pivot axis is arranged in a lower region of the limit switch weight, opposite a suspension point of the limit switch weight. Preferably, the pivot axis is formed by a bolt that is shorter than the limit switch weight or the molded parts. By arranging the joint or bolt only in the lower region of the limit switch weight, it is better protected from damage caused by the lifting cable. In particular, the joint is thus located outside the area through which the lifting cable moves and which positions the limit switch weight around the lifting cable. Preferably, the bolt is held in one of the molded parts by a tension pin. This mounting method allows the use of a solid bolt.The joint forming the pivot axis of the stroke limit switch weight may include a fork-finger connection which is penetrated by the bolt.

[0024] In another possible embodiment, the molded parts can be detachably locked together in the closed position by a locking device. This secures the limit switch weight against unintentional opening. The locking device preferably also serves as a suspension point for the limit switch weight, allowing it to be suspended from a crane or, in particular, connected to a sensor of a limit switch assembly via a coupling device. Preferably, this suspension point is the only suspension point for the limit switch weight. The locking mechanism can be achieved by connecting the weight to a coupling device (e.g., a carabiner) at the suspension point.

[0025] In another possible embodiment, the locking device comprises two connecting elements, each arranged or formed on one of the molded parts. In the simplest case, these can be connecting tabs or bolt eyes. In the closed position, the connecting elements are arranged adjacent to one another, so that they can be connected to each other via a locking element of the locking device, thereby locking the molded parts. The locking element can be, for example, a bolt or carabiner that is inserted through the connecting elements. The connecting elements can simultaneously form one (preferably the only) suspension point for the limit switch weight, with the locking element serving as the connection to a coupling means and thus fulfilling a dual function (suspension and locking of the limit switch weight).

[0026] In another possible embodiment, the connecting elements and the locking element are designed such that, in the locked state, the locking element presses the molded parts together or at least significantly restricts the degree of freedom of pivoting movement about the common pivot axis. In other words, the molded parts are pressed together or held together by the shape and arrangement of the connecting elements and the locking element, resulting in only a narrow opening gap, which reduces the risk of the lifting cable or an external branch strand becoming trapped. The locking element can be a carabiner whose curvature provides the compression.

[0027] Alternatively or additionally, the connecting elements and the locking element can be designed such that, when locked, the locking element is inserted into the connecting elements at an angle of less than 90° to the center plane. At an angle of 90° to the center plane, the components have the greatest degree of play to move apart slightly despite being locked, which increases the risk of the lifting cable becoming trapped in the opening gap. The smallest amount of play occurs at an angle of 0°, i.e., when the locking element is inserted parallel to the center plane through the connecting elements. However, since this could lead to a collision between the locking element and the lifting cable running in the opening, the angle is preferably between 0° and 90°, for example, between 20° and 70°.An angle range of 30-60° is preferred, as this represents a good compromise between effective protection against unintentional opening and avoiding collisions with the lifting cable.

[0028] In another possible embodiment, one or more of the molded parts have a laterally projecting support section, the underside of which forms part of a support surface for the limit switch weight, allowing the weight to be placed on the ground. The support section thus increases the contact or support surface on the underside of the limit switch weight. This support surface simultaneously forms the stop surface against which the lifting element strikes the limit switch weight from below, triggering the sensor of the associated limit switch assembly. A larger stop surface for the lifting element also prevents jamming between the limit switch weight and elements of the lifting element (e.g., pulleys of a hook block). The support section is preferably located in the area of ​​the pivot axis. The entire support surface can have a substantially rectangular shape.

[0029] In another possible embodiment, the molded parts have stops that contact each other in an open position of the limit switch weight and block further opening of the molded parts. In at least one molded part, the stop is preferably formed on a laterally projecting stop section, which may preferably be arranged in the region of the pivot axis. The stop section can simultaneously form the aforementioned stop section or represent a separately projecting section. The stop section can also have an underside that forms part of the stop surface of the limit switch weight.

[0030] Furthermore, additional projecting sections or bulges can be provided to cover gaps that arise or close during the swiveling movement, thus minimizing the risk of crushing injuries to people and materials. For example, the molded parts in the rear upper area can have overlapping tabs that also form a stepped or labyrinthine gap, preventing the lifting cable from becoming trapped. The rear area is located on the side of the swivel axis.

[0031] The present invention further relates to a limit switch assembly comprising a limit switch weight according to the invention. The same advantages and properties are evident as for the limit switch weight according to the invention, therefore a repetitive description is omitted. In addition, the limit switch assembly comprises a sensor which is connected to the limit switch weight via a coupling means. The coupling means can be, for example, a chain or a rope. The coupling means can be attached to a suspension point of the limit switch weight via a locking element. The sensor of the limit switch assembly is configured to detect movement of the limit switch weight.

[0032] This can include, in particular, detecting when the lifting of the limit switch weight exceeds a defined maximum height by relieving the coupling device during lifting, which in turn is registered by the sensor.

[0033] The invention further relates to a crane, in particular a mobile crane. This crane comprises a hoist rope, a boom with a boom head over which the hoist rope is guided, and a hoist limit switch arrangement according to the invention. The term boom head is to be interpreted broadly and need not refer to a component mounted on the boom. It could, for example, be the boom tip with one or more pulleys. This obviously results in the same advantages and properties as for the hoist limit switch weight according to the invention, which is why a repetitive description is omitted. The hoist limit switch arrangement is preferably arranged in the region of the boom head. Preferably, the hoist limit switch arrangement is arranged such that the hoist rope of the crane passes through the opening of the hoist limit switch weight when it is in the closed position. The sensor of the hoist limit switch arrangement can be attached to the boom or boom head.

[0034] The hoisting cable carries a lifting element (e.g., a hook block) located below the lifting limit switch weight. When the lifting element reaches its maximum permissible lifting height (defined in particular by the underside of the lifting limit switch weight), it strikes the weight from below, lifting it and thereby relieving the coupling element. This is registered by the sensor and preferably communicated to a control unit (especially the crane control system), which then automatically stops any further lifting or retraction of the hoisting cable by a hoist winch.

[0035] The crane can comprise a mobile undercarriage and a superstructure mounted on the undercarriage, with a swiveling boom. The boom can be, for example, a lattice boom that can be luffed by means of a cable pulley system or a telescopic boom that can be luffed by means of one or more hydraulic luffing cylinders.

[0036] Further features, details and advantages of the invention will become apparent from the exemplary embodiments explained below with reference to the figures. The figures show: Fig. 1: a side view of the crane according to the invention in an exemplary embodiment; Fig. 2: a schematic side view of the stroke limit switch arrangement according to an exemplary embodiment; Fig. 3: a schematic front view of the stroke limit switch arrangement according to a further embodiment; Fig. 4: a perspective view of a preferred embodiment of the stroke limit switch weight in the closed position; Fig. 5: the lifting limit switch weight in the open position; and Fig. 6-7: Top views of the underside and top of the stroke limit switch weight in the closed position.

[0037] In the Fig. Figure 1 shows an embodiment of the crane 1 according to the invention in the form of a mobile crawler crane in a side view. The crane 1 comprises an undercarriage 2 with crawler tracks and a superstructure 3 rotatably mounted on the undercarriage 2 about a vertical axis of rotation. A telescopic boom 5 is pivotally connected to the superstructure 3 about a horizontal axis, with the raising and lowering of the boom 5 being effected by one or more rocker cylinders 4. In this embodiment, a boom head 6 is mounted at the free end of the boom 5, over which a hoist cable 7 is guided for moving loads.

[0038] In this embodiment, the boom head 6 is designed as a pulley head with a neck pulley and several deflection pulleys, but in principle, it can have any shape. The deflection pulleys installed in the pulley head 6 can form the upper block of a block and tackle for lifting heavy loads, with the lower block being formed by a hook block 9 (= lifting element), which can include several deflection pulleys on which the hoist rope 7 is guided. The latter is wound on a hoist winch 8 attached to the superstructure 3. By operating the hoist winch 8, the hoist rope 7 can be pulled in or lowered, thereby raising or lowering the hook block 9. The hoist winch 8 is preferably operated via a crane control system. The end of the hoist rope 7 not wound on the hoist winch 8 can be detachably attached to the boom 5 or the boom head 6, for example, by means of a padlock.Alternatively, the lifting rope 7 could end at the hook bottle 9.

[0039] It should be noted that the crane 1 shown is only one possible embodiment. For example, the crane could also be a mobile crane with a wheeled chassis or a stationary crane. Furthermore, instead of a telescopic boom, a boom system with a main boom, boom tip, and possibly a derrick boom could be used. Additionally, instead of a hook block 9, a different lifting element, such as a spreader beam, could be used.

[0040] During crane operation, it is important to prevent the hoist rope 7 from being retracted too far. In this case, the hook block 9 might be raised so high that it collides with crane components on the boom 5. To prevent this, the crane 1 has a hoist limit switch assembly 100. This assembly includes a hoist limit switch weight 10, which encloses a section of the hoist rope 7, allowing the hoist rope 7 to move relative to the hoist limit switch weight 10. The hoist limit switch weight 10 is, in effect, suspended from the hoist rope 7 and can move along it (but is held at a defined height during operation by a coupling device 82).

[0041] An embodiment of such a limit switch arrangement 100 is shown in a schematic side view in the Fig. 2 shown. In this embodiment, the boom tip is shown as follows: Fig. 2 trained differently than in the Fig. 1, which, however, is not important for the functioning of the limit switch arrangement 100.

[0042] The lifting limit switch weight 10 is connected via a coupling means 82, for example a chain or wire or synthetic rope, to a sensor 80 of the lifting limit switch assembly 100 mounted on the boom 5 (or boom head 6). The lifting limit switch weight 10 holds the sensor 80 in a defined position. The latter preferably transmits this position to a crane control system and releases the crane movement (e.g., retracting the hoist rope 7). If the hook block 9 approaches the components of the boom 5 too closely, the hook block 9 strikes the lifting limit switch weight 10 from below and lifts it. This relieves the coupling means 82, which the sensor 80 registers. In this position, crane 1 operations are prohibited, and the crane movement is preferably stopped automatically. The distance between the hook block 9 and the components to be protected on the boom 5 depends not only on the directly observable unwound length of the hoist rope 7.Indirect crane movements, such as telescoping or rocking the boom 5, also affect the distance involved.

[0043] The Fig. Figure 3 shows a frontal view of a stroke limit switch arrangement 100 according to a further embodiment, in which the stroke limit switch weight 10 is, in contrast to the embodiment of the Fig. 2 is not arranged between a deflection pulley 64 of the boom 5 and the hook block 9, but between the fastening element 84 of the lifting cable 7 on the boom (e.g., a pocket lock) and a deflection pulley 92 of the hook block 9. The part of the lifting cable 7 enclosed by the lifting limit switch weight 10 is referred to here as the main strand 72, and the strands of the lifting cable 7 running between the deflection pulleys 64 of the boom head ("upper block") and the deflection pulleys 92 of the hook block 9 ("lower block") are referred to as secondary strands 74. In the exemplary embodiment of the Fig. 3 One of the branch lines 74 borders the end-of-stroke switch weight 10 laterally from the outside. Alternatively, the end-of-stroke switch weight 10 could also be suspended from one of the branch lines 74.

[0044] The Fig. Figures 4-7 show a preferred embodiment of the limit switch weight 10 according to the invention. This comprises two hinged half-shells or molded parts 11, 12 which can be pivoted relative to each other about a pivot axis 14. The molded parts 11, 12 are shaped such that in the closed position (cf. Figure 4-7) they are... Fig. 4) form a passage 16 through which the lifting cable 7 runs when installed. The in the Fig. Line 4, designated with reference numeral 15, represents the longitudinal axis 15 running centrally through the opening 16, which coincides with the longitudinal axis of the lifting cable 7 in the assembled state. The longitudinal axis 15 is parallel to the pivot axis 14. Fig. Figure 4 shows the lifting limit switch weight 10 in the closed position, in which it completely encloses the (not shown) lifting cable 7, while in the Fig. 5 the lifting limit switch weight 10 is shown in the open position, in which the lifting rope 7 can be removed from or inserted into the lifting limit switch weight 10.

[0045] The pivot bearing defining the pivot axis 14 is formed by a bolt 18 (see below). Fig. 5) This penetrates a fork-finger connection 26 between the molded parts 11, 12. In the illustrated embodiment, the bolt 18 is secured by a tension pin 19 in one of the molded parts 11, 12. The pivot bearing does not extend over the entire length (extension along the longitudinal axis 15) of the limit switch weight 10, but only in its lower region. The length of the bolt 18 is selected such that it does not protrude beyond the material of the molded parts 11, 12 at any point. This protects it from damage or wear by the lifting cable 7. The two molded parts 11, 12 also form a flat support surface 21 on the underside of the limit switch weight 10. This support surface 21 is preferably large. The storage area 21 is preferably enlarged by means of two indentations 22, 24 formed in the lower area of ​​the molded parts 11, 12.

[0046] The Fig. Figure 6 shows a top view of the underside or support surface 21 of the closed limit switch weight 10. It can be seen that the support surface 21 in the illustrated embodiment is essentially rectangular, which is achieved on one side by the two protrusions 22, 24. Of course, differently shaped support surfaces are also conceivable. One of the protrusions 22 forms a support section 22 and is specifically designed to provide the limit switch weight 10 with a large contact surface when the hook block 9 approaches it, thus preventing jamming between the limit switch weight 10 and elements of the hook block 9. The other protrusion 24 forms a stop section and constitutes a mechanical stop formed on a first molded part 11 for the other (second) molded part 12, in order to limit the opening angle of the two molded parts 11, 12 when pivoting about their pivot axis 14.The support section 22 and the stop section 24 can be formed integrally on the molded part 11. Furthermore, additional projections can be provided to cover gaps that arise or close during the opening movement, thus minimizing crushing risks for people and materials.

[0047] With the lifting limit switch weight 10 mounted, the hoist cable 7 runs along the longitudinal axis 15 within the opening 16, ideally exactly in its center. The lifting limit switch weight 10 is not symmetrical to the hoist cable 7 or opening 16, but rather has a larger dimension and thus a greater mass on one side (which is affected on the crane 1, in particular, by the secondary strands 74 of the hoist cable 7). As a result, the center of gravity 50 of the lifting limit switch weight 10 lies laterally outside the opening 16. The position of the center of gravity 50 in the illustrated embodiment is shown in the Fig. 7 can be seen, which shows a top view of the top of the stroke limit switch weight 10.

[0048] The plane passing through the longitudinal axis 15 and the center of gravity 50 is here referred to as the median plane 48. The pivot axis 14 of the two molded parts 11, 12 does not lie within the median plane 48, but is laterally offset from it, i.e., it is arranged eccentrically. This protects the joint forming the pivot axis 14 from damage by the lifting cable 7, which can occur if the lifting limit switch weight 10 is tilted (e.g., in an arrangement according to Fig. 2, in which the limit switch weight 10 is held obliquely from above by the coupling means 82) no longer presses or rubs against the joint. The protection is enhanced by the fact that the bolt 18 is only located at the bottom of the limit switch 10. In the upper area of ​​the passage 16, which is contacted by the lifting cable 7 when the limit switch weight 10 is tilted, two overlapping sections 35 of the molded parts 11, 12 are formed (see Figure 2). Fig. 4), which in the illustrated embodiment form two interlocking L-shaped webs or lugs. No hinge is provided in this rear upper area. The stepped gap formed by the sections 35 also prevents the enclosed main strand 72 or a secondary strand 74 from becoming jammed. In addition, the upper section of this gap, bordering the top of the lifting limit switch weight 10, is offset from the central plane 48, so that the lifting cable 7 presses against the web of the first molded part 11 when tilted.

[0049] In the Fig. In the embodiment shown in Figures 4-7, the opening gap 34 formed on the other side of the two molded parts 11, 12, which is formed by the walls 31, 32 of the molded parts 11, 12 abutting each other in the closed state and opens when the molded parts 11, 12 are pivoted apart, is not planar or straight, but stepped. In this embodiment, the aforementioned walls 31, 32 each have two steps and thus an overall step-like shape (see Figure 4-7). Fig. 6). The resulting labyrinthine gap 34 or opening area of ​​the limit switch weight 10 lies on the side of the passage 16 opposite the bolt 18.

[0050] If the two molded parts 11, 12 open unintentionally (for example, because a locking mechanism allows some play), the walls 31, 32 move slightly apart. The stepped, labyrinthine shape of the gap 34 prevents the enclosed lifting cable 7 or a secondary strand 74 from becoming trapped. For the enclosed area of ​​the lifting cable 7, the radially closer "step" of the opening gap 34, located closer to the longitudinal axis 15, is particularly important and limits the passage for the lifting cable 7. This ensures that the latter remains securely guided in the opening 16. The same applies to the outer secondary strand 74. Here, the radially more outwardly located "step" of the opening gap 34 is important and limits the passage for the secondary strand 74. Due to the stepped design of the opening gap 34, it does not run parallel to the central plane 48, but rather at an angle to it.

[0051] The cross-section of the passage 16 can deviate from a circular shape. In the illustrated embodiment, the cross-section on the side of the pivot axis 15 has a substantially semicircular shape, while the cross-section on the side of the opening gap 34 has a more angular shape (see figure). Fig. 6).

[0052] The stroke limit switch weight 10 can have an overall elongated shape (cf. Fig. 4) As a result, the limit switch weight 10 interferes less with adjacent secondary strands 74. The mass is therefore preferably formed by an elongated body and not by an almost cube-shaped weight, as is often the case in the prior art. This supports the deliberately chosen distribution of the material position for the molded parts 11, 12.

[0053] The molded parts 11, 12 can, for example in the area of ​​the passage 16, have recesses 17 (see Fig. 5) to influence the weight distribution or the position of the center of gravity 50. The recesses 17 can be designed or positioned such that the lifting cable 7 is still well guided and the center of gravity 50 has a sufficient distance from the opening 16. In the design according to the Fig. 4-7 The recesses 17 in the molded parts 11, 12 create a web 13 in the first molded part 11, which remains in the same position relative to the first molded part 11 during the pivoting movement of the second molded part 12. Thus, the web 13 is particularly suitable as a gripping surface during assembly and disassembly and for handling the lifting limit switch weight 10. The web 13 also forms a wall of the passage 16 and thus protects the lifting cable 7.

[0054] The molded parts 11, 12 can be detachably locked together in the closed position by means of a locking device 40 to prevent opening or detachment from the lifting cable 7. Preferably, a separate closure is omitted for this purpose. In the illustrated embodiment, connecting elements in the form of connecting tabs 41, 42 are formed on the upper surfaces of the molded parts 11, 12, each having a through-hole or bore. In the closed state, the through-holes of the connecting tabs 41, 42 overlap (see figure). Fig. 4), so that a locking element can be pushed through. This could be, for example, a 44mm carabiner (see...). Fig. 3), which connects the limit switch weight 10 to a coupling means 82. The carabiner 44 can perform a dual function and press the molded parts 11, 12 together by means of its curvature.

[0055] The connecting tabs 41, 42 preferably form the only suspension point of the end-of-stroke switch weight 10 and are therefore located in particular exactly above the center of gravity 50 (cf. Fig. 7), so that the stroke limit switch weight 10 in the absence of an additional force (such as in the case of an inclined suspension according to Fig. 2) is aligned straight (i.e., the longitudinal axis 15 runs vertically). The suspension point can also be much longer than shown in the Fig. 2 shown.

[0056] In the illustrated embodiment, the connecting tabs 41, 42 are deliberately not arranged parallel to an outer wall of the limit switch weight 10, but rotated by approximately 30°. This results in an angle between the insertion direction 46 of the locking element (see dashed line in the figure). Fig.7) and the central plane 48 at approximately 60°. Of course, other angles are also possible. Ideally, the insertion direction 48 would be aligned parallel to the central plane 48, as this would result in the least play between the two molded parts 11 and 12 in the closed position. However, the locking element (e.g., the aforementioned carabiner 44) must not protrude into the area of ​​influence of the lifting cable 7 or into the opening 16.

[0057] All components forming the assembly of the limit switch weight 10 are preferably permanently mounted and constitute a single, coherent unit. Reference symbol list: 1 Mobile crane 2 undercarriages 3 upper carriages 4 rocker cylinders 5 outriggers 6 cantilever head 7 Lifting rope 8 Lifting winch 9 Carrying device (hook bottle) 10 Stroke limit switch weight 11 First molded part 12 Second molded part 13 Bridge 14 Swivel axis 15 Longitudinal axis 16 Passage 17 recess 18 bolts 19 Tension pin 21 parking spaces 22 Parking section 24 Stop section 26 Fork-finger connection 31 First contact surface 32 Second contact surface 34 gap 35 Rear gap 36 First Stage 37 Second stage 40 Locking device 41 First connecting element 42 Second connecting element 44 Locking element (carabiner) 46 Insertion direction 48 Middle level 50 Focus 64 Pulley 72 Main strand 74 Branch 80 Sensor 82 coupling devices 84 Fastening element 92 Pulley 100 limit switch arrangement

Claims

[1] Lift limit switch weight (10) for a crane (1) with two molded parts (11, 12) pivotably connected about a pivot axis (14), which in a closed position together form a passage (16) for receiving a lifting rope (7), wherein the molded parts (11, 12) are designed such that the center of gravity (50) of the lift limit switch weight (10) is spaced apart in the closed position from a longitudinal axis (15) running centrally along the passage (16), characterized by , that the pivot axis (14) is offset laterally to a median plane (48) of the stroke limit switch weight (10) passing through the longitudinal axis (15) and the center of gravity (50). [2] Stroke limit switch weight (10) according to claim 1, wherein the center of gravity (50) is located outside the passage (16) in the closed position, wherein the center of gravity (50) is preferably arranged below a suspension point of the stroke limit switch weight (10) so that the longitudinal axis (15) runs vertically in the suspended state. [3] Stroke limit switch weight (10) according to one of the preceding claims, wherein the molded parts (11, 12) have contact surfaces (31, 32) which face each other in the closed position and form a gap (34) extending between the passage (16) and an outer surface of the stroke limit switch weight (10), wherein the contact surfaces (31, 32) preferably have radii and / or edges extending from the longitudinal axis (15) in the radial direction, forming a labyrinthine gap (34) in the closed position. [4] Stroke limit switch weight (10) according to the preceding claim, wherein the contact surfaces (31, 32) each have at least one right-angled step, preferably at least two right-angled steps (36, 37), which interlock in a step-like manner in the closed position. [5] Stroke limit switch weight (10) according to one of the two preceding claims, wherein the gap (34) in the closed position is located on one side of the passage (16) opposite the pivot axis (14) and / or passes through the center of gravity (50) of the stroke limit switch weight (10). [6] Stroke limit switch weight (10) according to one of the preceding claims, wherein the molded parts (11, 12) are shaped differently and / or are designed such that the passage (16) has a cross-section that deviates from a circular shape, in particular not being symmetrical to the central plane (48). [7] Stroke limit switch weight (10) according to one of the preceding claims, wherein in the closed position it has a greater extent along the longitudinal axis (15) (length) than transversely to the longitudinal axis (15) (width), wherein preferably the stroke limit switch weight (10) in the closed position is wider along the median plane (48) than transversely to the median plane (48) and / or is at least twice as long as its width transversely to the median plane (48). [8] Stroke limit switch weight (10) according to one of the preceding claims, wherein the pivot axis (14) is arranged in a lower region of the stroke limit switch weight (10) opposite a suspension point and is preferably formed by a bolt (18) which has a shorter length than the stroke limit switch weight (10), wherein the bolt (18) is held in particular by a tension pin (19) in one of the molded parts (11, 12). [9] Stroke limit switch weight (10) according to one of the preceding claims, wherein the molded parts (11, 12) can be detachably locked together in the closed position by a locking device (40), wherein the locking device (40) preferably forms a suspension point, particularly preferably the only suspension point in the closed position, of the stroke limit switch weight (10). [10] Stroke limit switch weight (10) according to the preceding claim, wherein the locking device (40) comprises two connecting elements (41, 42) which are each arranged on one of the molded parts (11, 12) and adjacent to each other in the closed position, so that they can be connected to each other via a locking element (44) of the locking device (40) and the molded parts (11, 12) can be locked thereby, wherein the connecting elements (41, 42) in particular form the suspension point of the stroke limit switch weight (10). [11] Stroke limit switch weight (10) according to the preceding claim, wherein the connecting elements (41, 42) and the locking element (44) are designed such that the locking element (44) in the locked state presses the molded parts (11, 12) against each other and / or is inserted into the connecting elements (41, 42) at an angle of less than 90° to the central plane (48). [12] Limit switch weight (10) according to one of the preceding claims, wherein at least one of the molded parts (11, 12) has a laterally projecting support section (22) whose underside is part of a support surface (21) of the limit switch weight (10), via which the limit switch weight (10) can be placed on the ground, wherein the support section (22) is preferably arranged in the area of ​​the pivot axis (14). [13] Stroke limit switch weight (10) according to one of the preceding claims, wherein the molded parts (11, 12) have stops which contact each other in an open position of the stroke limit switch weight (10) and block further opening of the molded parts (11, 12), wherein preferably the stop of at least one of the molded parts (11, 12) is formed on a laterally projecting stop section (24), which is arranged in particular in the area of ​​the pivot axis (14). [14] Lift limit switch arrangement (100) for limiting the maximum permissible lifting height of a lifting rope, comprising a lift limit switch weight (10) according to one of the preceding claims and a sensor (80) which is connected to the lift limit switch weight (10) via a coupling means (82), in particular a chain or a rope, and is designed to detect a movement of the lift limit switch weight (10). [15] Crane (1), in particular a mobile crane, comprising a lifting rope (7) with a rigging device (9) attached thereto, a boom (5) with a boom head (6) over which the lifting rope (7) is guided, and a lifting limit switch arrangement (100) preferably arranged in the area of ​​the boom head (6) according to the preceding claim, wherein the lifting rope (7) passes through the opening (16) of the lifting limit switch weight (10) in the closed position.

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