Hoist limit switch weight and crane with such

Abstract

The invention relates to a hoist limit switch weight for a crane, comprising two molded parts pivotally connected to one another about a pivot axis, which, in a closed position, jointly form a passage for receiving a hoist rope. According to the invention, the molded parts are designed such that, in the closed position, the center of gravity of the hoist limit switch weight is spaced from a longitudinal axis running centrally along the passage, and the pivot axis is laterally offset from a center plane of the hoist limit switch weight running through the longitudinal axis and the center of gravity. The invention further relates to a hoist limit switch arrangement for limiting the maximum permissible lifting height of a hoist rope, which comprises a hoist limit switch weight according to the invention, and to a crane having such a hoist limit switch arrangement.

Description

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

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

[0003] During retraction of the hoist rope, it must be ensured that the lifting height of the hoist rope is limited in such a way that the suspension device attached to the hoist rope (typically a crane hook or hook block) does not collide with the guide device (e.g., the deflection pulleys of a boom head). Retracting the hoist rope beyond the maximum permissible lifting height would result in damage to the guide device, the boom itself, or even the breaking of the hoist rope or suspension device, causing the lifted load to fall. To prevent this, the actual lifting height of the hoist rope, suspension device, or load must be constantly monitored and communicated, for example, to a crane control system.

[0004] To monitor the lifting height, hoist limit switches are typically used. These sensors detect movement or the exceeding of a defined maximum height by the lifting device, which can automatically stop any further retraction of the hoist cable via the hoist cable winch. For this purpose, a hoist limit switch weight is connected to a sensor via a coupling device and guided longitudinally along the hoist cable. If the lifting device is raised too far, it strikes the hoist limit switch weight from below and lifts it. This relieves the load on the coupling device of the hoist limit switch, which is registered by the sensor.

[0005] Hoist limit switch weights are known from the prior art. These consist of several individual parts that must be assembled on the hoist rope during erection. However, assembly is time-consuming and cumbersome due to the relatively large mass of the hoist limit switch weight. There are also solutions in which the hoist limit switch weight has two pivoting, folding parts that can be placed around the hoist rope and connected to each other. However, over many years of use, this could lead to wear or damage to the joint caused by the hoist rope.

[0006] The present invention is therefore based on the object of providing a hoist limit switch weight which is easy to assemble and is constructed in such a way that wear or damage to the hoist limit switch weight and the hoist rope is avoided.

[0007] According to the invention, this object is achieved by a device having the features of claim 1. Advantageous embodiments of the invention emerge from the subclaims and the following description.

[0008] Accordingly, a hoist limit switch weight is proposed, comprising two molded parts that are connected to one another in an articulated manner, i.e., pivotable about a pivot axis. The molded parts are designed such that, in a closed position, they jointly form a passage for receiving a hoist cable. The passage is defined by both molded parts. In the assembled state, the hoist cable runs through the passage, so that it is enclosed by the hoist limit switch weight.

[0009] According to the invention, the molded parts are designed such that the center of gravity of the hoist limit switch weight, in the closed position, is spaced from the longitudinal axis of the passage of the hoist limit switch weight. The latter is defined such that it runs centrally along the passage (i.e. parallel to the hoist cable when the hoist cable is straight and the hoist limit switch weight is not tilted relative to the hoist cable). This allows the hoist limit switch weight to be suspended from a coupling means via a single suspension point without tilting too far. For this purpose, the suspension point is arranged above the center of gravity. This enables a simple and compact design of the hoist limit switch weight. In order to achieve such a center of gravity, the hoist limit switch weight can have a greater mass on one side of the passage than on the opposite side.

[0010] According to the invention, the molded parts are further designed such that the pivot axis is offset laterally from a center plane of the hoist limit switch weight running through the longitudinal axis and the center of gravity. The pivot axis is therefore not centrally located in a plane containing the center of gravity and the longitudinal axis. This eccentric arrangement of the pivot axis protects it from damage to the hoist cable, since tilting of the hoist limit switch weight relative to the hoist cable occurs within the center plane due to the position of the center of gravity, and the pivot axis lies outside of said center plane. With a centrally arranged pivot axis, if the hoist limit switch weight tilts, the hoist cable could strike the joint area of the molded parts and thus cause damage over time.

[0011] In principle, the molded parts can be designed in any desired manner, although they preferably have a different or asymmetrical structure. The molded parts are preferably solid cast parts to provide the required weight for the lifting limit switch assembly. The molded parts can optionally have recesses to specifically influence the weight distribution or the position of the center of gravity.

[0012] The molded parts, together with the swivel axis, preferably form a coherent assembly with firmly connected components. This eliminates the need to handle multiple individual parts, simplifying assembly / disassembly.

[0013] 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 hoist rope.

[0014] In one possible embodiment, the center of gravity of the hoist limit switch weight lies outside the passage in the closed position. In the installed state, the hoist limit switch weight therefore has a greater mass or a greater extent on one side of the hoist rope than on the opposite side. In the installed state, the side with the lower mass can face other secondary strands of the hoist rope, which can, for example, be reeved several times between a hook block and a sheave head. The center of gravity is preferably arranged below a suspension point of the hoist limit switch weight, so that the longitudinal axis or the passage runs in particular vertically in the suspended state without external force (such as a force exerted by the hoist rope).

[0015] In a further possible embodiment, the molded parts have contact surfaces that face each other in the closed position and form a gap between the passage and an outer side of the hoist limit switch weight. When the molded parts are pivoted apart, the hoist limit switch weight opens and the contact surfaces move away from each other, allowing the hoist rope to be inserted or extended in the open position. When the molded parts are pivoted towards each other, the hoist limit switch weight closes and the contact surfaces move towards each other until they lie against each other and the hoist rope is completely enclosed by the molded parts.

[0016] The contact surfaces preferably have curves and / or edges extending radially from the longitudinal axis, which form a labyrinth-shaped gap in the closed position. Compared to flat contact surfaces, this offers the advantage that the hoist rope cannot become trapped in the gap. If the molded parts pivot slightly apart during operation, the labyrinth-shaped design of the opening area of the hoist limit switch weight prevents the hoist rope or any secondary strand of the hoist rope adjacent to the outside of the hoist limit switch weight from becoming accidentally trapped. Preferably, the opening gap in the closed position runs obliquely (as a complete labyrinth) to the aforementioned center plane.

[0017] In another possible embodiment, the contact surfaces each have at least one rectangular step, preferably at least two rectangular steps, which, in the closed position, interlock or rest on top of each other in a stepped manner. This at least one step forms a barrier for the hoist rope, 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 hoist limit switch weight.

[0018] In another possible embodiment, the gap is located on a side of the passage opposite the pivot axis in the closed position. Alternatively or additionally, the center of gravity of the limit switch weight can be located in the area of the gap in the closed position, or the gap can run through the center of gravity.

[0019] 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 passage has a cross-section that deviates from a circular shape, in particular, that is not symmetrical to the center plane. This can result from the pivot axis being eccentric and the gap being labyrinthine, and the gap not running parallel to the center plane.

[0020] In a further possible embodiment, the hoist limit switch weight, in its closed position, has a greater extent along the longitudinal axis (referred to here as length) than transversely to the longitudinal axis (referred to here as width). The hoist limit switch weight can have a substantially cuboid shape overall, although other shapes are also conceivable. Due to the greater length compared to the width, the hoist limit switch weight takes up less space in the area next to the hoist rope, thus reducing, for example, the risk of a collision with a secondary strand of the hoist rope. The hoist limit switch weight can be at least twice as long as it is wide, whereby the stated width can refer to an extent transverse to the center plane.

[0021] Preferably, the lifting limit switch weight is wider along the center plane in the closed position than across the center plane. This allows a weight distribution to be achieved in which the center of gravity of the lifting limit switch weight is located next to the passage and preferably in the center plane.

[0022] In a further possible embodiment, the pivot axis is arranged in a lower region of the hoist limit switch weight, opposite a suspension point of the hoist limit switch weight. The pivot axis is preferably formed by a bolt that is shorter than the hoist limit switch weight or the molded parts. By arranging the joint or the bolt only in the lower region of the hoist limit switch weight, the latter is better protected against damage caused by the hoist cable. In particular, the joint is thus located outside the area through which the hoist cable moves and which positions the hoist limit switch weight around the hoist cable. The bolt is preferably held in one of the molded parts by a dowel pin. This type of assembly enables the use of a bolt made of solid material.The joint forming the pivot axis of the stroke limit switch weight may comprise a fork-finger connection penetrated by the bolt.

[0023] In a further possible embodiment, the molded parts can be releasably locked together in the closed position by a locking device. This allows the hoist limit switch weight to be secured against unintentional opening. The locking device preferably simultaneously forms a suspension point for the hoist limit switch weight, via which the latter can be suspended from a crane or, in particular, connected to a sensor of a hoist limit switch arrangement via a coupling means. Preferably, said suspension point is the only suspension point for the hoist limit switch weight. Locking can be achieved by a connection to a coupling means (e.g., by means of a carabiner) at the suspension point.

[0024] In a further 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 straps or bolt eyes. The connecting elements are arranged adjacent to one another in the closed position, so that they can be connected to one another via a locking element of the locking device, and the molded parts can thereby be locked. The locking element can be, for example, a bolt or snap hook that is inserted through the connecting elements. The connecting elements can simultaneously form one (preferably the only) suspension point for the hoist limit switch weight, whereby the locking element can serve as a connection to a coupling means and thus fulfill a dual function (suspending and locking the hoist limit switch weight).

[0025] 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 against each other 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 hoist rope or an outer secondary strand becoming trapped. The locking element can be a carabiner, the curvature of which ensures the pressing.

[0026] Alternatively or additionally, it can be provided that the connecting elements and the locking element are designed such that the locking element, in the locked state, is pushed into the connecting elements at an angle of < 90° to the center plane. At an angle of 90° to the center plane, the molded parts have the greatest scope to move apart slightly despite being locked, which increases the risk of the hoist cable becoming trapped in the opening gap. The smallest scope of play occurs at an angle of 0°, i.e. when the locking element is pushed through the connecting elements parallel to the center plane. However, since this could lead to a collision between the locking element and the hoist cable running in the passage, 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 collision avoidance with the hoist rope.

[0027] In a further possible embodiment, one or more of the molded parts has a laterally projecting support section, the underside of which forms part of a support surface for the hoist limit switch weight, via which the hoist limit switch weight can be placed on the ground. The support section therefore enlarges the contact or support surface on the underside of the hoist limit switch weight. This support surface simultaneously forms the stop surface against which the suspension element strikes the hoist limit switch weight from below and lifts it up to trigger the sensor of the associated hoist limit switch arrangement. A larger stop surface for the suspension element simultaneously prevents jamming between the hoist limit switch weight and elements of the suspension element (e.g. deflection rollers of a hook block). The support section is preferably arranged in the region of the pivot axis. The entire support surface can have an essentially rectangular basic shape.

[0028] In a further possible embodiment, the molded parts have stops that contact each other when the limit switch weight is in the open position 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 can preferably be arranged in the region of the pivot axis. The stop section can simultaneously form the aforementioned support section or represent a separately projecting section. The stop section can also have an underside, which is part of the support surface of the limit switch weight.

[0029] In addition, additional overhanging sections or bulges can be provided to cover gaps that arise or close during the pivoting movement, thus minimizing the risk of crushing for people and materials. For example, the molded parts can have overlapping lugs in the rear upper area, which also form a stepped or labyrinthine gap that prevents the hoist rope from becoming trapped. The rear area is located on the side of the pivot axis.

[0030] The present invention further relates to a hoist limit switch assembly comprising a hoist limit switch weight according to the invention. This obviously results in the same advantages and properties as the hoist limit switch weight according to the invention, which is why a repeated description is omitted. Furthermore, the hoist limit switch assembly comprises a sensor connected to the hoist limit switch weight via a coupling means. The coupling means can be, for example, a chain or a cable. The coupling means can be fastened to a suspension point of the hoist limit switch weight via a locking element. The sensor of the hoist limit switch assembly is designed to detect movement of the hoist limit switch weight.

[0031] This may in particular include detecting a lifting of the lifting limit switch weight beyond a defined maximum height by relieving the coupling means during lifting, which in turn is registered by the sensor.

[0032] The invention further relates to a crane, in particular a mobile crane. This 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 does not have to represent a component mounted on the boom. This can be, for example, the boom tip with one or more deflection 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 repeated description is omitted. The hoist limit switch arrangement is preferably arranged in the region of the boom head. The hoist limit switch arrangement is preferably arranged such that the hoist rope of the crane runs through the passage 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.

[0033] The hoist rope carries a suspension element (e.g., a hook block) located below the hoist limit switch weight. When the suspension element reaches its maximum permissible lifting height (which is defined, in particular, by the underside of the hoist limit switch weight), it strikes the hoist limit switch weight from below, lifting it and thereby relieving the load on the coupling element. This is registered by the sensor and preferably communicated to a control unit (in particular, the crane control system), which preferably automatically stops any further lifting or retraction of the hoist rope by a hoist rope winch.

[0034] The crane may comprise a mobile undercarriage and a superstructure mounted on the undercarriage for rotation, with a pivoting boom. The boom may, for example, be a lattice boom that can be luffed by means of a cable pull system or a telescopic boom that can be luffed by means of one or more hydraulic luffing cylinders.

[0035] Further features, details, and advantages of the invention will become apparent from the exemplary embodiments explained below with reference to the figures. They show: Fig. 1: a side view of the crane according to the invention according to an embodiment; Fig. 2: a schematic side view of the stroke limit switch arrangement according to an 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 stroke limit switch weight in the open position; and Fig. 6-7: Top views of the bottom and top of the stroke limit switch weight in the closed position.

[0036] In the Fig. Figure 1 shows a side view of an embodiment of the crane 1 according to the invention in the form of a mobile crawler crane. The crane 1 comprises an undercarriage 2 with crawler tracks and an uppercarriage 3 mounted on the undercarriage 2 for rotation about a vertical axis of rotation. A telescopic boom 5 is pivotably connected to the uppercarriage 3 about a horizontal axis, with the boom 5 being luffed up and down via one or more luffing cylinders 4. In this embodiment, a boom head 6 is mounted at the free end of the boom 5, over which a hoist rope 7 is guided for moving loads.

[0037] In this embodiment, the boom head 6 is designed as a pulley head with a neck roll 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 pulley system for lifting heavy loads, whereby the lower block can be formed by a hook block 9 (= suspension means), which can comprise several deflection pulleys on which the hoist cable 7 is guided. The latter is wound on a hoist cable winch 8 attached to the superstructure 3. By operating the hoist cable winch 8, the hoist cable 7 can be retracted or lowered, thereby raising or lowering the hook block 9. The hoist cable winch 8 is preferably operated via a crane control system. The end of the hoist cable 7 not wound on the hoist cable winch 8 can be releasably attached to the boom 5 or the boom head 6, for example by means of a pocket lock.Alternatively, the hoist rope 7 could end at the hook block 9.

[0038] 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 provided. Furthermore, instead of a hook block 9, another lifting device, such as a crossbeam, could be used.

[0039] During crane operation, it is important to avoid over-retracting the hoist rope 7. In this case, the hook block 9 would possibly be lifted so far that it collides with crane components on the boom 5. To prevent this, the crane 1 has a hoist limit switch arrangement 100. This comprises a hoist limit switch weight 10, which encloses one strand of the hoist rope 7 so that the hoist rope 7 can move relative to the hoist limit switch weight 10. The hoist limit switch weight 10 hangs, so to speak, from the hoist rope 7 and can move along the hoist rope 7 (but is held at a defined height during operation by a coupling means 82).

[0040] An embodiment of such a stroke limit switch arrangement 100 is shown in a schematic side view in the Fig. 2. The boom tip in the embodiment of the Fig. 2 trained differently than in the Fig. 1, which, however, is not important for the functioning of the stroke limit switch arrangement 100.

[0041] The hoist 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 hoist limit switch arrangement 100 mounted on the boom 5 (or boom head 6). The hoist limit switch weight 10 holds the sensor 80 in a defined position. The latter preferably transmits this position to a crane control system and enables the crane movement (e.g., retraction of the hoist rope 7). If the hook block 9 approaches the components of the boom 5 too closely, the hook block 9 impacts the hoist limit switch weight 10 from below and lifts it. This relieves the coupling means 82, which is registered by the sensor 80. In this position, work by the crane 1 is 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 detectable unwound length of the hoist rope 7.Indirect crane movements such as telescoping or luffing of the boom 5 also influence the affected distance.

[0042] The Fig. 3 shows a front view of a lifting limit switch arrangement 100 according to the invention according to a further embodiment, in which the lifting limit switch weight 10, in contrast to the embodiment of the Fig. 2 is not arranged between a deflection roller 64 of the boom 5 and the hook block 9, but between the fastening element 84 of the hoist rope 7 on the boom (e.g. a pocket lock) and a deflection roller 92 of the hook block 9. The part of the hoist rope 7 enclosed by the hoist limit switch weight 10 is referred to here as the main strand 72 and the strands of the hoist rope 7 running between the deflection rollers 64 of the boom head (“upper block”) and the deflection rollers 92 of the hook block 9 (“lower block”) are referred to as secondary strands 74. In the embodiment of the Fig. 3, one of the secondary strands 74 borders laterally from the outside on the lifting limit switch weight 10. Alternatively, the lifting limit switch weight 10 could also hang on one of the secondary strands 74.

[0043] The Fig. 4-7 show a preferred embodiment of the limit switch weight 10 according to the invention. This comprises two hingedly connected half-shells or molded parts 11, 12, which can be pivoted relative to one another about a pivot axis 14. The molded parts 11, 12 are shaped such that in the closed position (cf. Fig. 4) form a passage 16 through which the hoist rope 7 runs when mounted. Fig. 4, the line designated by reference numeral 15 represents the longitudinal axis 15 running centrally through the passage 16, which in the assembled state coincides with the longitudinal axis of the hoist rope 7. The longitudinal axis 15 is parallel to the pivot axis 14. The Fig. 4 shows the hoist limit switch weight 10 in the closed position, in which it completely encloses the hoist rope 7 (not shown), while in the Fig. 5 the hoist limit switch weight 10 is shown in the open position in which the hoist rope 7 can be removed from or inserted into the hoist limit switch weight 10.

[0044] The pivot bearing defining the pivot axis 14 is formed by a bolt 18 (cf. Fig. 5). This penetrates a fork-finger connection 26 between the molded parts 11, 12. In the embodiment shown, the bolt 18 is secured by a dowel pin 19 in one of the molded parts 11, 12. The pivot bearing does not run over the entire length (= extension along the longitudinal axis 15) of the hoist limit switch weight 10, but only in its lower area. 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 erosion by the hoist cable 7. The two molded parts 11, 12 also form a flat support surface 21 on the underside of the hoist limit switch weight 10. This support surface 21 is preferably designed to be large. The storage area 21 is preferably enlarged by two bulges 22, 24 formed in the lower area of the molded parts 11, 12.

[0045] The Fig. 6 shows a plan view of the underside or support surface 21 of the closed hoist 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 bulges 22, 24. Of course, other shaped support surfaces are also conceivable. One of the bulges 22 forms a support section 22 and is specifically provided so that the hoist limit switch weight 10 offers a large contact surface when the hook block 9 abuts, and jamming between the hoist limit switch weight 10 and elements of the hook block 9 is avoided. The other bulge 24 forms a stop section and forms a mechanical stop, formed on a first shaped part 11, for the other (second) shaped part 12, in order to limit the opening angle of the two shaped parts 11, 12 when pivoting about their pivot axis 14.The stop section 22 and the stop section 24 can be formed integrally on the molded part 11. Furthermore, additional recesses can be provided to cover gaps that arise or close during the pivoting movement, thus minimizing the risk of crushing for people and materials.

[0046] The hoist rope 7 runs, with the hoist limit switch weight 10 mounted, along the longitudinal axis 15 within the passage 16, ideally exactly in its center. The hoist limit switch weight 10 is not designed symmetrically to the hoist rope 7 or passage 16, but has a greater extension and thus a greater mass on one side (which is spaced apart on the crane 1, in particular, by the secondary strands 74 of the hoist rope 7). As a result, the center of gravity 50 of the hoist limit switch weight 10 lies laterally outside the passage 16. The position of the center of gravity 50 in the illustrated embodiment is shown in the Fig. 7, which shows a plan view of the top side of the stroke limit switch weight 10.

[0047] The plane passing through the longitudinal axis 15 and the center of gravity 50 is referred to herein as the center plane 48. The pivot axis 14 of the two molded parts 11, 12 is not located within the center plane 48, but laterally offset from it, ie it is arranged eccentrically. This protects the joint forming the pivot axis 14 from damage by the hoist cable 7, which, when the hoist limit switch weight 10 is tilted (e.g., in an arrangement according to Fig. 2, in which the hoist 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 arranged at the bottom of the hoist limit switch 10. In the upper area of the passage 16, which is contacted by the hoist cable 7 when the hoist limit switch weight 10 is tilted, two overlapping sections 35 of the molded parts 11, 12 are formed (cf. Fig. 4), which in the embodiment shown form two interlocking L-shaped webs or lugs. No joint 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 jamming. In addition, the upper section of this gap, bordering the top side of the hoist limit switch weight 10, is offset from the center plane 48, so that the hoist cable 7 presses against the web of the first molded part 11 in the tilted state.

[0048] 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 walls 31, 32 of the molded parts 11, 12 abutting against one another 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 (cf. Fig. 6). The resulting labyrinth-like gap 34 or opening area of the stroke limit switch weight 10 lies on the side of the passage 16 opposite the bolt 18.

[0049] If the two molded parts 11, 12 are opened unintentionally (for example, because a provided locking mechanism allows a certain amount of play), the walls 31, 32 move slightly apart. The stepped, labyrinth-like shape of the gap 34 prevents the enclosed hoist rope 7 or a secondary strand 74 from becoming trapped. For the enclosed area of the hoist rope 7, the "step" of the opening gap 34, which is radially closer to the longitudinal axis 15, comes into play in particular and limits the passage for the hoist rope 7. This ensures that the latter continues to be safely guided in the passage 16. The same applies to the outer secondary strand 74. Here, the "step" of the opening gap 34, which is radially further out, comes into play and limits the passage for the secondary strand 74. Due to the stepping of the opening gap 34, it does not run parallel to the center plane 48, but rather at an angle to it.

[0050] The cross-section of the passage 16 may 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 (cf. Fig. 6).

[0051] The stroke limit switch weight 10 can have an elongated shape overall (cf. Fig. 4). As a result, the stroke limit switch weight 10 engages less with adjacent secondary strands 74. The mass is thus preferably formed by an elongated body rather than a nearly cube-shaped weight, as is often the case in the prior art. This supports the specifically selected distribution of the material layer for the molded parts 11, 12.

[0052] The molded parts 11, 12 can have recesses 17, for example in the area of the passage 16 (cf. Fig. 5) in order to influence the weight distribution or the position of the center of gravity 50. The recesses 17 can be designed or positioned in such a way that the hoist cable 7 is nevertheless well guided and the center of gravity 50 has a sufficient distance from the passage 16. In the design according to the Fig. 4-7, the recesses 17 of 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 preferably suitable as an engagement surface during assembly and disassembly and for handling the hoist limit switch weight 10. The web 13 also forms a wall of the passage 16 and thus protects the hoist rope 7.

[0053] In the closed position, the molded parts 11, 12 can be releasably locked together by means of a locking device 40 to prevent opening or detachment from the hoist rope 7. Preferably, a separate closure is omitted for this purpose. In the embodiment shown, connecting means in the form of connecting tabs 41, 42 are formed on the upper sides of the molded parts 11, 12, each having a passage or bore. In the closed state, the passages of the connecting tabs 41, 42 overlap (see. Fig. 4) so that a locking element can be pushed through. This can be, for example, a carabiner 44 (cf. Fig. 3), which connects the limit switch weight 10 to a coupling means 82. The carabiner 44 can fulfill a dual function and press the molded parts 11, 12 together through its curvature.

[0054] The connecting straps 41, 42 preferably form the only suspension point of the lifting limit switch weight 10 and are therefore located in particular exactly above the center of gravity 50 (cf. Fig. 7), so that the lifting 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 (ie the longitudinal axis 15 is vertical). The suspension point can also be much longer than in the Fig. 2 shown.

[0055] In the illustrated embodiment, the connecting tabs 41, 42 are deliberately not arranged parallel to an outer wall of the lifting limit switch weight 10, but are rotated by approximately 30°. This results in an angle between the insertion direction 46 of the locking element (see dashed line in Fig.7) and the center plane 48 of approximately 60°. Other angles are also possible, of course. Ideally, the insertion direction 48 would be aligned parallel to the center plane 48, as this would ensure that the two molded parts 11, 12 have the least amount of play in the closed position. However, the locking element (e.g., the aforementioned snap hook 44) must not protrude into the sphere of influence of the hoist rope 7 or into the passage 16.

[0056] All components that form the assembly of the lifting limit switch weight 10 are preferably permanently mounted and represent a single, coherent unit. List of reference symbols: 1 mobile crane 2 undercarriages 3 superstructures 4 rocker cylinders 5 booms 6 boom head 7 hoist rope 8 hoist winch 9 Lifting device (hook block) 10 Lift limit switch weight 11 First molded part 12 Second molded part 13 jetty 14 Swivel axis 15 Longitudinal axis 16 Passage 17 Recess 18 bolts 19 dowel pin 21 storage space 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 sensors 82 coupling agents 84 Fastening element 92 pulley 100 stroke limit switch arrangement

Claims

[1] Hoist limit switch weight (10) for a crane (1) with two molded parts (11, 12) pivotably connected to one another about a pivot axis (14), which in a closed position together form a passage (16) for receiving a hoist rope (7), characterized by that the shaped parts (11, 12) are designed such that the center of gravity (50) of the lifting limit switch weight (10) in the closed position is spaced from a longitudinal axis (15) running centrally along the passage (16) and the pivot axis (14) is offset laterally to a center plane (48) of the lifting limit switch weight (10) running through the longitudinal axis (15) and the center of gravity (50). [2] Lift 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 lift limit switch weight (10) so that the longitudinal axis (15) runs vertically in the suspended state. [3] Lift limit switch weight (10) according to one of the preceding claims, wherein the shaped parts (11, 12) have contact surfaces (31, 32) which face one another in the closed position and form a gap (34) extending between the passage (16) and an outer side of the lift limit switch weight (10), wherein the contact surfaces (31, 32) preferably have roundings and / or edges starting from the longitudinal axis (15) in the radial direction, which form a labyrinth-shaped gap (34) in the closed position. [4] Lift limit switch weight (10) according to the preceding claim, wherein the contact surfaces (31, 32) each have at least one rectangular step, preferably at least two rectangular steps (36, 37), which engage in a step-like manner in the closed position. [5] Lift limit switch weight (10) according to one of the two preceding claims, wherein the gap (34) in the closed position is located on a side of the passage (16) opposite the pivot axis (14) and / or extends through the center of gravity (50) of the lift limit switch weight (10). [6] Lift limit switch weight (10) according to one of the preceding claims, wherein the shaped parts (11, 12) are differently shaped and / or are designed such that the passage (16) has a cross-section deviating from a circular shape, which in particular is not symmetrical to the center plane (48). [7] Lift 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 lift limit switch weight (10) in the closed position is wider along the central plane (48) than transversely to the central plane (48) and / or is at least twice as long as its width transversely to the central plane (48). [8] Lift limit switch weight (10) according to one of the preceding claims, wherein the pivot axis (14) is arranged in a lower region of the lift limit switch weight (10) opposite a suspension point and is preferably formed by a bolt (18) which has a shorter length than the lift limit switch weight (10), wherein the bolt (18) is held in one of the shaped parts (11, 12) in particular by a clamping pin (19). [9] Lift limit switch weight (10) according to one of the preceding claims, wherein the shaped parts (11, 12) can be releasably locked together by a locking device (40) in the closed position, wherein the locking device (40) preferably forms a suspension point, particularly preferably the only suspension point in the closed position, of the lift limit switch weight (10). [10] Lift 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 one another in the closed position, so that they can be connected to one another 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 lift limit switch weight (10). [11] Lift 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 shaped 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 center plane (48). [12] Lift limit switch weight (10) according to one of the preceding claims, wherein at least one of the shaped parts (11, 12) has a laterally projecting storage section (22), the underside of which is part of a storage surface (21) of the lift limit switch weight (10), via which the lift limit switch weight (10) can be placed on the ground, wherein the storage section (22) is preferably arranged in the region of the pivot axis (14). [13] Lift limit switch weight (10) according to one of the preceding claims, wherein the shaped parts (11, 12) have stops which contact each other in an open position of the lift limit switch weight (10) and block further opening of the shaped parts (11, 12), wherein preferably the stop of at least one of the shaped parts (11, 12) is formed on a laterally projecting stop section (24), which is arranged in particular in the region of the pivot axis (14). [14] Hoist limit switch arrangement (100) for limiting the maximum permissible lifting height of a hoist rope, comprising a hoist limit switch weight (10) according to one of the preceding claims and a sensor (80) which is connected to the hoist 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 hoist limit switch weight (10). [15] Crane (1), in particular a mobile crane, comprising a hoisting rope (7) with a lifting means (9) attached thereto, a boom (5) with a boom head (6) over which the hoisting rope (7) is guided, and a hoisting limit switch arrangement (100) according to the preceding claim, preferably arranged in the region of the boom head (6), wherein the hoisting rope (7) runs through the passage (16) of the hoisting limit switch weight (10) in the closed position thereof.

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