Locking device for telescopic cylinder

Abstract

Locking device (10) for the telescopic cylinder of a telescopic boom comprising a plurality of telescopic stages. The locking device comprises a housing (12), at least one bolt (20) displaceably mounted in the housing for locking the telescopic cylinder with a telescopic stage, a yoke (30) displaceably mounted in the housing, which is movable into an unlocking position for releasing a locking bolt of the telescopic boom, and at least one blocking element (35), which blocks a movement of the bolt into its unlocking position when the yoke is in the unlocking position. The at least one bolt is preloaded into a locking position via at least one bolt return element (22) and can be displaced via at least one bolt actuator (24) into an unlocking position releasing the telescopic stage lock. The blocking element and the bolt can be at least partially displaced into a common insertion space of the housing. According to the invention, the bolt is preloaded into the locking position via at least two bolt return elements, wherein the blocking element is arranged between the bolt return elements as seen in the displacement direction of the yoke. The invention further relates to an implement, in particular a mobile crane, having a locking device according to the invention.

Description

[0001] Locking device for telescopic cylinder

[0002] The invention relates to a locking device for the telescopic cylinder of a telescopic boom comprising several telescopic sections according to the preamble of claim 1 and to a working device, in particular a mobile crane, comprising such a device.

[0003] Telescopic booms comprise an outer telescopic section (also called the base section or pivot section) and one or more inner telescopic sections slidably mounted within it. Such telescopic booms are used, for example, in mobile cranes. Especially with larger telescopic booms, a hydraulic telescopic cylinder is usually used to extend and retract the telescopic sections sequentially. For this purpose, one part of the telescopic cylinder, typically its piston rod, is connected to the base of the outer telescopic section, while the other part, typically the cylinder, extends and retracts relative to the outer telescopic section by pressurizing the corresponding pressure chamber.

[0004] To move the individual telescopic sections, the telescopic cylinder must be temporarily connected to them. The solution typically used for this purpose provides a locking device (also called a locking head) on the telescopic cylinder, particularly on its piston rod-side end or collar. This locking device engages the inner telescopic section to be extended from the inside via several spring-returned bolts, so that the telescopic section extends together with the telescopic cylinder.

[0005] The individual telescopic sections can also be locked to each other in defined extension positions via spring-loaded locking bolts on the telescopic sections. To unlock or lock locking bolts for extending or retracting telescopic sections, they can be gripped by the locking device and moved into an unlocked position. For this purpose, the locking device typically has a spring-returned yoke that can be engaged with the pull-out mushrooms of the locking bolt rods that extend inward into the telescopic sections.

[0006] The movement of the bolts and yoke against the restoring forces into the respective unlocking positions is typically achieved via hydraulic actuators. Safety latches installed on the yoke mechanism ensure that the bolts cannot be retracted simultaneously when the yoke is in the unlocked position, thus retaining the free or unlocked telescopic section through the telescoping cylinder. This is typically achieved by the safety latches blocking the travel path of the bolts. When the yoke is in the locked position, the travel path of the bolts is unobstructed, and they can be moved into the unlocked position by applying pressure to the corresponding actuators.

[0007] In devices of this type, the yoke is slidably mounted and guided by several guide elements in a housing of the locking device. In some known solutions, these guide elements are arranged outside the center plane, which is spanned by the longitudinal axes of the lateral bolts and the direction of displacement of the yoke, while the safety latches are located within this center plane. However, this requires a relatively large installation space and can lead to the yoke becoming jammed in the housing. If the guide elements are to be relocated to this center plane, this would result in a spatial conflict with the actuation and return mechanism of the bolts, which are usually preloaded by centrally arranged return springs. This means that the return springs of the yoke must be arranged outside the center plane, which in turn requires more installation space.

[0008] The present invention is therefore based on the object of avoiding the disadvantages of the prior art and developing it in an advantageous manner. In particular, in a generic locking device for telescopic booms, the aim is to ensure good guidance of the yoke in the housing while optimally utilizing the available space.

[0009] This object is achieved by a locking device having the features of claim 1. Advantageous embodiments of the invention emerge from the subclaims and the following description.

[0010] Accordingly, a locking device for the telescopic cylinder of a telescopic boom is proposed, which comprises a plurality of telescopic sections slidably mounted within one another. The locking device comprises a housing, at least one bolt slidably mounted in the housing for locking the telescopic cylinder to a telescopic section, a yoke slidably mounted in the housing, which can be moved into an unlocking position to release a locking bolt of the telescopic boom, and at least one blocking element that blocks movement of the bolt in its unlocking position when the yoke is in the unlocking position. The at least one bolt is preloaded into a locking position via at least one bolt return element and can be moved into an unlocking position that releases the telescopic section lock via at least one bolt actuator.The blocking element and the bolt can be moved at least partially into a common insertion space in the housing. The at least one blocking element prevents both the yoke and the at least one bolt from being in the unlocked position at the same time. This ensures that either all telescopic sections are locked together via one or more locking bolts or that the locking device is locked to one of the inner telescopic sections and the latter is therefore held or secured by the telescoping cylinder. The yoke and the at least one bolt thus block each other, so that each of these elements can only be moved into the unlocked position when the other element is in the locking position.

[0011] According to the invention, the bolt is preloaded into the locking position by at least two bolt return elements, with the blocking element being arranged between the bolt return elements, as seen in the direction of displacement of the yoke. The latter can also include the case where the blocking element is offset from the bolt return elements but arranged between their extended longitudinal axes. Preferably, however, the bolt return elements are actually arranged around the blocking element.

[0012] This configuration enables a compact design of the locking device, since the space previously occupied by the central bolt return spring in the area of ​​the bolt's longitudinal axis is now free and used for the blocking element. In prior art solutions, however, the safety latches had to be provided with special recesses because the safety latches and the central bolt return springs interfered with each other. In particular, the arrangement according to the invention makes it possible to arrange a yoke return element in the area of ​​the at least one blocking element, thereby achieving a very compact design.

[0013] At the same time, the configuration is very easy to install. Individual parts can be conveniently pre-assembled. The bolt return elements are preferably springs or compression springs. These can be guided by spring domes. It is also conceivable that the springs can be pre-tensioned using screws before installation. This enables safe assembly and maintenance of the system.

[0014] In one possible embodiment, the at least one blocking element is simultaneously designed as a guide element, via which the yoke is guided in the housing. The blocking element preferably has a guide section that is displaceably mounted and guided in a guide of the housing. The guide section is preferably cylindrical.

[0015] The at least one blocking element thus performs a dual function: on the one hand, guiding the yoke in the housing and, on the other hand, blocking the unlocking movement of the bolts when the yoke is in the unlocked position. This combined function eliminates the need for any additional guide elements to support or guide the yoke in the housing, apart from the at least one blocking element. This results in less space being required within the locking device.

[0016] Furthermore, the actuators for moving the yoke into the unlocking position (yoke actuators) can be arranged in the same plane as the blocking element, which acts as a guide element. In the prior art, the locking latch and / or yoke actuators, on the one hand, and the guide elements, on the other, are often arranged offset in the direction of displacement of the bolt. This results in improved guidance of the yoke in the housing, since no additional torque is introduced into the device, which would reduce the smooth movement of the yoke.

[0017] The yoke actuators can, for example, be designed as plunger cylinders.

[0018] Likewise, return elements which pre-tension the yoke into the locking device (yoke return elements), such as compression springs, do not in themselves constitute guide elements within the meaning of the invention. Rather, the guide elements of the locking device according to the invention serve, in particular, primarily to guide the yoke in the housing during a movement from the locking position to the unlocking position and vice versa.

[0019] In another possible embodiment, the bolt return elements extend perpendicular to the longitudinal axis of the blocking element. In particular, the bolt return elements are oriented parallel to the longitudinal axis or displacement direction of the bolt.

[0020] Alternatively or additionally, the bolt return elements can extend at least partially within the insertion space. The at least one blocking element can be at least partially surrounded by the bolt return elements, or the latter can be arranged on both sides of the blocking element in the insertion space.

[0021] In another possible embodiment, the bolt is preloaded into the locking position via at least two, preferably exactly four, bolt return elements. The bolt return elements are preferably arranged symmetrically to the longitudinal axis of the bolt or to a plane passing through the longitudinal axis of the bolt.

[0022] Alternatively or additionally, the bolt return elements are arranged symmetrically to the longitudinal axis of the blocking element, as seen in the displacement direction of the bolt. This includes the case where the bolt return elements are arranged symmetrically to a plane containing the longitudinal axis of the blocking element, in particular symmetrically to a plane spanned by the longitudinal axis of the blocking element and the longitudinal axis of the bolt.

[0023] In another possible embodiment, the yoke is preloaded into a locking position by at least one yoke return element and can preferably be displaced into the unlocking position by at least one yoke actuator against the preload force of the yoke return element. The yoke actuator can be designed to push the yoke into the unlocking position or to pull the yoke into the unlocking position. The yoke return element can be a compression spring.

[0024] In a further possible embodiment, the blocking element has a blocking section that, when the yoke is in the unlocked position, projects into a travel path of the bolt in the insertion space and blocks movement of the bolt in its unlocked position. When the yoke is in the locked position, the blocking section lies outside the bolt travel path. The blocking section preferably has no recess and / or a constant width when viewed from the side along the bolt travel path.

[0025] The blocking element preferably further comprises a contact section that is connected to or contacted by the at least one yoke actuator. The contact section preferably extends transversely to the longitudinal axis of the blocking element. The blocking element is connected to the yoke such that pressing down (in the case of a "pushing" yoke actuator) or pulling down (in the case of a "pulling" yoke actuator) the contact section results in the yoke being displaced into the unlocking position. The contact section is preferably located above (if the side of the locking device on which the yoke is located is considered "top") the blocking section.

[0026] In a further possible embodiment, two yoke actuators are provided, which are preferably arranged symmetrically to the blocking element, viewed in the direction of displacement of the bolt. The yoke actuators are therefore located on both sides of the blocking element, viewed in the direction of displacement of the bolt, and are at the same distance from it. This advantageously ensures that no additional torque is introduced into the blocking element via the yoke actuators. In a further possible embodiment, the yoke return element is a compression spring, which is arranged coaxially to the blocking element. This results in a particularly space-saving arrangement, in which the compression spring acts axially on the blocking element and is arranged within the insertion space between the bolt return elements.In particular, there is no need to arrange multiple compression springs at a distance from the blocking element, as is common in the prior art, which would increase the required installation space. Preferably, the compression spring is partially accommodated in a spring receptacle of the blocking element. The spring receptacle of the blocking element can be realized by a recess open downwards (i.e., facing away from its attachment to the yoke), in which the compression spring is seated.

[0027] Alternatively or additionally, the compression spring can be mounted or guided on a spring dome connected to the housing. Ideally, the compression spring can be preloaded using a preload element, such as a threaded spindle, for easy installation. However, conventional installation is also possible.

[0028] In a further possible embodiment, it is provided that the yoke return element is arranged at least partially in the insertion space, wherein the bolt preferably has a recess on an end face facing the yoke return element, which recess at least partially encloses or surrounds the yoke return element in the unlocked position of the bolt. Thus, the yoke return element as such does not block the movement of the bolt into the unlocked position. The recess in the bolt is in particular U-shaped and engages around the yoke return element in the unlocked position. The blocking element is preferably designed such that it cannot be encompassed by the recess in the bolt when the yoke is in the unlocked position, i.e. it is wider than the recess. Alternatively, the blocking section of the blocking element can also block the bolt at a different location, for example to the side of the recess. Preferably, the recess orthe blocking element is designed in such a way that the bolt in its unlocking position blocks retraction of the blocking element and thus movement of the yoke into its unlocking position.

[0029] In another possible embodiment, the yoke actuator comprises or represents a hydraulic cylinder, in particular a plunger cylinder. A plunger is suitable for a particularly space-saving arrangement within the structure of the locking device. In particular, it can be easily arranged above the insertion area, for example, perpendicular to the bolt. The blocking element is preferably actuated by two plungers.

[0030] In a further possible embodiment, the bolt actuator comprises or represents a hydraulic cylinder, in particular a plunger cylinder. Preferably, several plungers are provided for moving the bolt. The plungers are advantageously arranged symmetrically to the longitudinal axis of the blocking element, viewed in the displacement direction of the bolt. This includes the case where the plungers are arranged symmetrically to a plane containing the longitudinal axis of the blocking element, in particular symmetrically to a plane spanned by the longitudinal axis of the blocking element and the longitudinal axis of the bolt. This results in a uniform movement of the bolt without the generation of additional torque.

[0031] In a further possible embodiment, two bolts are provided for locking the telescopic cylinder with a telescopic section, wherein each bolt is assigned at least one blocking element, which is arranged between the bolt return elements of the yoke, viewed in the direction of displacement of the yoke. The bolts are located in particular on opposite sides of the locking device, while the yoke is arranged on its upper side. The preceding explanations regarding possible configurations of the yoke, the bolts, the blocking element and the various return elements and actuators apply analogously to an embodiment with two bolts. In particular, exactly one blocking element is provided per bolt. The yoke is therefore preferably pretensioned into the locking position via a total of two yoke return elements and can be moved into the unlocking position via at least four, in particular exactly four, yoke actuators.Each of the two bolts is held in the locked position by a blocking element when the yoke is in the unlocked position.

[0032] The two blocking elements, in particular, simultaneously function as guide elements, as described above. In one embodiment, no further guide elements are provided besides these two guide elements formed by the blocking elements, so that the yoke is mounted and guided in the housing by exactly two guide elements. These two guide elements are located, in particular, within a central plane running through the center of the yoke, in which the longitudinal axes of the bolts preferably also lie.

[0033] In an alternative possible embodiment, exactly two blocking elements are provided, which function as guide elements, with an additional guide element being provided, so that the yoke is guided in the housing via a total of three guide elements. The additional guide element is preferably arranged outside a center plane defined by the longitudinal axes of the blocking elements. The additional guide element comprises, in particular, a guide rod connected to the yoke or to an underside of the yoke, which is slidably mounted and guided in a guide of the housing.

[0034] In principle, however, it is also conceivable that more than one additional guide element is provided, so that the yoke, including the two blocking elements acting as guide elements, is slidably mounted and guided in the housing via a total of four, five or more guide elements.

[0035] In a further possible embodiment, it is provided that the blocking elements are arranged centrally on opposite sides of the yoke, wherein the longitudinal axes of the blocking elements preferably lie in a common plane with the longitudinal axes of the bolts.

[0036] In a further possible embodiment, it is provided that exactly four yoke return elements are provided, which are arranged axially symmetrically to a central plane spanned by the longitudinal axes of the blocking elements and preferably axially symmetrically to a plane running perpendicular thereto.

[0037] In a plan view of the locking device, four yoke return elements are preferably provided, which form the corners of a rectangle.

[0038] In a view along the direction of movement of the bolts, preferably two or four bolt return elements are provided which form the corners of a rectangle.

[0039] In a view along the direction of movement of the bolts, preferably four bolt actuators are provided, which form the corners of a rectangle.

[0040] In a further possible embodiment, an end section of the blocking element projecting into a stroke or travel path of the bolt within the insertion space has an opening on its front side that is completely enclosed by a wall. The end section can form a blocking section of the blocking element, as described above. The end section therefore does not have a recess open to one side, such as a C-shaped section when viewed from the side. The opening is preferably circular. The opening preferably serves to accommodate the yoke return element, such that the yoke return element projects from the insertion space through the opening into a spring receptacle of the blocking element or is received therein. The spring receptacle can in particular be enclosed by the aforementioned wall, at least part of the spring receptacle.In a further possible embodiment, a dome receiving space adjoins the spring receptacle, wherein the dome receiving space is formed within the blocking element. The dome receiving space is designed such that a spring dome running in the insertion space, on which the yoke return element is mounted, projects into the dome receiving space in an unlocked position of the yoke (in which the blocking element blocks the stroke or travel path of the bolt), so that the dome is located at least partially within the blocking element in the said dome receiving space. Furthermore, the spring receptacle and the dome receiving space are designed such that the yoke return element is always located outside the dome receiving space, i.e. does not protrude into the dome receiving space in any position of the yoke or the blocking element. The dome receiving space preferably has a smaller diameter than the spring receptacle.The dome receiving space can have a circular cross-section.

[0041] The present invention further relates to a work device, in particular a mobile crane, with a telescopic boom comprising several telescopic sections displaceably mounted one inside the other, a hydraulic telescopic cylinder for extending and retracting at least one inner telescopic section, and a locking device according to the invention connected to the telescopic cylinder. This obviously results in the same properties and advantages as the locking device according to the invention, which is why a repeated description is omitted here.

[0042] Further features, details, and advantages of the invention will become apparent from the following exemplary embodiments explained with reference to the figures. They show:

[0043] Figure 1: a first embodiment of the locking device according to the invention in a perspective view;

[0044] Figures 2a-b: the locking device according to Figure 1 in a frontal view and in a frontal sectional view through the two blocking elements; Figure 3: a plan view of the locking device according to Figure 1 in a section through the bolts at the level of the bolt return elements;

[0045] Figures 4a-b: the locking device according to Figure 1 in a side view and in a side sectional view through a blocking element;

[0046] Figures 5a-b: a second embodiment of the locking device according to the invention in a frontal sectional view through the two blocking elements and in a plan view; and

[0047] Figures 6a-c: a third embodiment of the locking device according to the invention in a frontal sectional view through the two blocking elements, in a lateral sectional view through a blocking element and in a perspective individual view of one of the blocking elements.

[0048] Figure 1 shows a perspective view of a first embodiment of the locking device 10 according to the invention. The locking device 10 represents a locking head of the telescoping cylinder of a telescopic boom with several telescopic sections mounted so as to be movable within one another. This can be the telescopic boom of a mobile crane. The locking head 10 serves to lock the telescopic sections to one another and to lock the telescoping cylinder to an inner telescoping section, as described above. The telescoping cylinder and the telescoping sections are not shown here.

[0049] To lock the locking device 10 with a telescopic section, bolts 20 (also referred to as driving bolts) are provided on opposite sides of the locking device 10. These bolts are slidably mounted in a housing 12 of the locking device 10 (see Fig. 2a). The longitudinal axes of the bolts 20 are arranged collinearly. The bolts 20 can engage in corresponding recesses of a telescopic section to be moved and drive it along with a retraction or extension movement of the telescoping cylinder.

[0050] As can be seen in the front view of the locking device 10 in Figure 2a, the housing 12 has a central opening or recess 11 in which the telescoping cylinder (not shown here) is accommodated. Above the recess 11 on the top side of the locking device 10 is a clamp-shaped yoke 30 (also referred to as a pull yoke), which is open at the top. The yoke 30 serves to grip and pull a locking bolt to release the locking of two telescopic sections.

[0051] Figure 2b shows a section through the locking device 10 perpendicular to the central recess 11 along the longitudinal axes of the bolts 20 (front view), thus providing a view of the interior of the locking device 10. A section along the central recess 11 through the bolts 20 (top view) is shown in Figure 3.

[0052] As the double arrows in Figure 2a indicate, the yoke 30 can move perpendicular to the direction of displacement of the bolts 20. The yoke 30 is pressed or preloaded upward into a locking position by two yoke return elements 32 designed as compression springs. The compression springs 32 are arranged diametrically on opposite sides of the yoke 30, specifically in plan view (see Fig. 3) in a line with the longitudinal axes of the bolts 20. The longitudinal axes of the compression springs 32 and the longitudinal axes of the bolts 20 are perpendicular to one another and lie in a common center plane 50, which runs in particular through the center of the yoke.

[0053] In order to pull a locking bolt and thus release the locking of two telescopic sections, the embodiment shown here features four hydraulic yoke actuators 34 in the form of plungers, which are arranged in pairs on opposite sides of the yoke 30 in the region of the compression springs 32. By applying pressure to the plungers 34, which are slidably mounted in plunger housings 31 arranged adjacent to the yoke 30, the yoke 30 can be pressed downward (i.e., in the direction of the recess 11) into an unlocking position against the spring forces of the compression springs 32. As soon as the plungers 34 are no longer subjected to pressure, the compression springs 32 automatically press the yoke 30 back into the locking position.

[0054] The bolts 20 are also preloaded into their locking position by bolt return elements 22 in the form of compression springs. In the embodiment shown here, exactly four compression springs 22 are provided per bolt 20, which press the respective bolt 20 outward (i.e., away from the recess 11). Alternatively, only two compression springs can be provided. Hydraulic bolt actuators 24 can move the bolts 20 toward the central recess 11, counter to the force applied by the compression springs 22, and thus into an unlocking position.

[0055] For safety reasons, it must be prevented that the yoke 30 and the bolts 20 are in their unlocked positions at the same time, so that the telescopic sections are locked at all times, either with each other or with the locking device 10. For this purpose, a safety mechanism is provided which only allows movement of the bolts 20 into their unlocked positions when the yoke 30 is in the locked position, and vice versa. The safety mechanism comprises two blocking elements 35, which are arranged diametrically on opposite sides of the yoke 30 and coaxial with the yoke return elements or compression springs 32.

[0056] Figure 4a shows the locking device 10 in a side view looking towards one of the lateral bolts 20, while Figure 4b shows a section perpendicular to the longitudinal axis of the bolt through the housing 12 in the region of one of the blocking elements 35 (side view). The blocking elements 35 are firmly connected to the yoke 30 in their upper end regions. For this purpose, the yoke 30 has laterally projecting connecting regions 18 to which the blocking elements 35 are fastened (in particular via a screw connection, although other fastening means are of course also conceivable). The blocking elements 35 extend inward into the housing 12 parallel to the direction of movement of the yoke 30. The blocking elements 35 have downwardly open recesses which form spring receptacles 39 in which the compression springs 32 are received. The compression springs 32 are mounted or guided on spring domes 33 (see Fig. 2b and 4b) which are fastened to the housing 12.

[0057] The spring domes 33 or compression springs 32 extend through a recess 14 within the housing 12, into which the bolts 20 are also pushed when they move into the unlocking position (see Figs. 2b and 3). The lower regions of the blocking elements 35 form blocking sections 37, which are located above the bolts 20 when the yoke 30 is in the locking position. In this state, the blocking sections 37 do not protrude into the recesses 14 of the bolts 20.

[0058] Due to their central arrangement, the compression springs 32 would block any inward movement of the bolts 20. Therefore, the bolts 20 each have a (in plan view) U-shaped recess 26 on their end faces facing the compression springs 32, the width of which is greater than the diameter of the compression spring 32 (see Fig. 3). The recesses 26 are thus designed such that when the bolts 20 move into the unlocked position, they engage around the compression springs 32, but the bolts 20 do not collide with the compression springs 32, so that the compression springs 32 are accommodated in the recesses 26 in the unlocked position.

[0059] If, however, the yoke 30 is in the unlocked position, the blocking sections 37 protrude into the insertion spaces 14 and block the movement of the bolts 20 into the unlocked position. For this purpose, the recesses 26 are designed such that they do not engage around the blocking sections 37 of the blocking elements 35, i.e., they have a smaller width than the blocking sections 37 (see Fig. 3). Conversely, the bolts 20, in their unlocked position, block the retraction of the blocking elements 35, so that in this state, the yoke 30 cannot move into the unlocked position.

[0060] Above the blocking sections 37, the blocking elements 35 each have a laterally projecting contact section 38, which can be seen in Figure 4b. The contact section 38 comprises two contact surfaces projecting perpendicular to the longitudinal axis of the corresponding blocking element 35, which are connected to the plungers 34 or are contacted by them from above. By extending the plungers 34, the blocking element 35 and thus the yoke 30 connected to it are moved downward into the unlocking position.

[0061] In the embodiment shown here, the plungers 34 and the blocking element 35 are arranged on each side of the yoke 30 in a common plane, i.e., they are not offset in the direction of movement of the bolts 20. This enables a compact design of the locking device 10 and avoids the introduction of additional moments into the blocking elements 35. However, it is also possible in principle to arrange the plungers 34 offset from the blocking elements 35 in the direction of movement of the bolts 20.

[0062] The central arrangement of the compression springs 32 and the blocking elements 35 with respect to the bolts 20 is achieved in that, in contrast to the prior art, the bolts 20 are not each mounted by a centrally located spring, i.e., arranged along the longitudinal axis of the bolt. Instead, each bolt 20 is preloaded by several (four in the present embodiment) compression springs 22, which are located laterally next to the blocking elements 35. As can be seen in Figures 3 and 4b, the compression springs 22 are arranged in pairs on either side of the compression springs 32, viewed along the direction of displacement of the bolts 20. The space thus freed up in the region of the longitudinal axis of the bolt is occupied by the compression springs 32 and the blocking elements 35, respectively. This results in a particularly compact design of the locking device 10.The possibility of dispensing with separate compression springs and instead arranging them coaxially to the blocking elements 35 also ensures a simpler design of the blocking elements 35.

[0063] At the ends facing the blocking elements 35, the bolts 20 have laterally projecting contact sections 28. The compression springs 22 are attached to these contact sections 28 on the side of each bolt 20 facing the insertion space 14, i.e., the compression springs 22 are arranged in the insertion space 14. The compression springs 22 can be mounted on spring domes. On the side of the contact sections 28 of each bolt 20 facing away from the insertion space 14 are the bolt actuators 24, which in this embodiment are also designed as plunger cylinders 24. By extending the plungers 24, the bolts 20 are pressed in the direction of the compression springs 32 and thus moved into the unlocking position.

[0064] In the embodiment shown here, four plungers 24 are provided per bolt 20, which can also be arranged in pairs on either side of the compression springs 32 or the blocking elements 35, as viewed along the displacement direction of the bolts 20. Alternatively, only two plungers 24 or more than two plungers 24 per bolt 20 can be provided.

[0065] The blocking elements 35 simultaneously represent the guide elements of the yoke 30 in the housing 12, which ensure a stable movement of the yoke 30. For this purpose, the blocking elements 35 each have a particularly cylindrical guide section 36 above the contact sections 38. The blocking elements 35 are slidably mounted and guided in guides or passages of the housing 12 of the locking device 10 via the guide sections 36.

[0066] In the embodiment shown here, the blocking elements 35 are guided through recesses in the plunger housings 31 arranged laterally next to the yoke 30, which essentially have a square LI shape. The blocking elements 35 are arranged between the two plungers 34. The actual guides for the guide sections 36 of the blocking elements 35 can be arranged in the central sections of the plunger housings 31, in the housing 12 below, or in both.

[0067] The plunger housings 31 can be considered as part of the housing 12.

[0068] Compared to prior art solutions, in which several separate piston rods are provided to guide the yoke, the blocking elements 35 thus also perform a dual function as the guide elements of the yoke 30. Separate piston rods can therefore be omitted, enabling a particularly compact design. Furthermore, the inventive arrangement of the blocking elements 35 ensures that the yoke 30, in the embodiment shown here, is guided by only two guide elements arranged in the center plane 50, which reduces the likelihood of jamming of the yoke 30 and increases its smooth movement.

[0069] The blocking, contact and guide sections 36, 37, 38 of the blocking elements 35 are preferably formed in one piece.

[0070] An alternative solution according to a second embodiment is illustrated in Figures 5a-b. Figure 5a shows the locking device 10 in a frontal sectional view through the two blocking elements 35, and Figure 5b shows a top view of the locking device 10. Reference numerals used for the first embodiment refer to the same components.

[0071] The locking device 10 according to the second embodiment differs from the first embodiment in that, in addition to the two blocking elements 35, a third guide element 40 is provided, so that the yoke 30 is mounted and guided via a total of three guide elements 35, 40, i.e., via a tripod in the housing 12. The further guide element 40 comprises a guide rod 42 connected to the underside of the clamp-shaped yoke 30, which is slidably mounted and guided in a corresponding guide or passage in the upper region of the housing 12. The guide or passage is thus located below the yoke 30.

[0072] As can be seen in Figure 5b, the additional guide element 40 in the embodiment shown here is arranged off-center with respect to the yoke 30, i.e., it is located outside the center plane 50 defined by the longitudinal axes of the bolts 20 and the blocking elements 35, as well as outside the plane extending perpendicular to the center plane 50 through the center of the yoke 30. The guide elements 35, 40 thus form the vertices of an irregular triangle. This results in the aforementioned tripod mounting of the yoke 30.

[0073] Alternatively, a tripod mounting arrangement could also be achieved by arranging the additional guide element 40 outside the center plane 50 but within the plane extending perpendicular to the center plane 50 through the center of the yoke 30, thus forming an isosceles triangle. It is also conceivable to provide more than one additional guide element 40.

[0074] Figures 6a-c show a third embodiment of the locking device 10 according to the invention. Figure 6a shows the locking device 10 in a frontal sectional view through two blocking elements 35, Figure 6b shows the locking device 10 in a lateral sectional view (rotated 90° to the view of Figure 6a) through one of the blocking elements 35 and Figure 6c shows a perspective view of one of the blocking elements 35 of this embodiment.

[0075] The locking device 10 according to the third embodiment differs from the first two embodiments in that the yoke return elements or compression springs 32 are mounted in a shallow spring receptacle 39 at the end portion of the respective blocking element 35, rather than on the top side of a bore extending through a substantial portion of the blocking element 35. As can be seen in Figure 6c, the blocking element 35 of this embodiment has a circular opening 60 on the end face facing away from the yoke 30, which opening is surrounded by a wall 62. The recess formed by the wall 62 forms the spring receptacle 39 for the compression spring 32, which is supported on an annular projection extending radially inward from the wall 62.The projection merges into a cylindrical bore extending within the blocking element 35 toward the yoke 30, forming a mandrel receiving space 66. The mandrel receiving space 66 has a smaller diameter than the spring receptacle 39, so that the compression spring 32 does not enter the mandrel receiving space 66 in any position of the blocking element 35.

[0076] As can be seen in Figures 6a and 6b, in which the yoke 30 is in the locking position, the compression springs 32 do not extend (far) inside the blocking elements 35, but are mounted at their end sections in the spring receptacles 39. In the unlocked position of the yoke 30, in which the blocking sections 38 of the blocking elements 35 protrude into the travel paths of the bolts 20, the compression springs 32 are compressed and the spring domes 33 protrude through the openings 60 into the dome receptacles 66 (not shown).

[0077] In order to maintain a sufficient length of the compression springs 32 despite the support of the compression springs 32 now taking place further down in the area of ​​the bolt return elements 22 on the blocking element 35, the bearing points of the spring domes 33 on the housing 12 of the locking device 10 are offset downward (i.e., away from the yoke 30) in this exemplary embodiment. For this purpose, pot-shaped dome bearing sections 64 are provided on the housing 12, to the bottoms of which the spring domes 33 are attached.

[0078] As shown in Figure 6c, the blocking elements 35 can have reinforcement sections 68 on the sides where the wing-shaped projections of the contact sections 38 for the yoke actuators 34 are located. These reinforcement sections 68 extend in the region of the blocking sections 37 and can be connected to the wall of the blocking element 35 or formed integrally with it. This allows the forces of the yoke actuators 34 to be better transmitted to the blocking elements 35, and the latter can be reinforced in these areas.

[0079] The blocking elements 35 can also have a shape in the first two embodiments, or more generally, that corresponds to that of Figure 6c, except for the front flat spring receptacle 39 and the narrower dome receiving space 66. In particular, the blocking elements 35 in the first two embodiments also have circular openings 60 for the compression springs 32 on the end faces of the end sections or blocking sections 37, which extend into the interior of the blocking elements 35 and are supported therein. Optionally, the reinforcement sections 68 shown can also be provided.

[0080] List of reference symbols:

[0081] 10 Locking device (locking head)

[0082] 11 Recess

[0083] 12 housings

[0084] 14 Insert space

[0085] 16 Screw

[0086] 18 Connection area

[0087] 20 bolts

[0088] 22 Bolt return element (spring)

[0089] 24 Bolt actuator (plunger)

[0090] 26 recess

[0091] 28 Contact section

[0092] 30 yoke

[0093] 31 Plunger housing

[0094] 32 Yoke return element (spring)

[0095] 33 spring dome

[0096] 34 Yoke actuator (plunger)

[0097] 35 Blocking element

[0098] 36 Guide Section

[0099] 37 Blocking section Contact section Spring holder Additional guide element Guide rod Center plane Opening Wall Dome bearing section Mandrel receiving space Reinforcement section

Claims

Patent claims Locking device (10) for the telescoping cylinder of a telescopic boom comprising several telescopic sections, comprising: - a case (12), - at least one bolt (20) slidably mounted in the housing (12) for locking the telescoping cylinder with a telescoping extension, wherein the bolt (20) is pre-tensioned into a locking position via at least one bolt return element (22) and is slidable into an unlocking position via at least one bolt actuator (24), - a yoke (30) slidably mounted in the housing (12), which can be moved into an unlocking position to release a locking bolt of the telescopic boom, - at least one locking element (35) which blocks movement of the bolt (20) in its unlocked position when the yoke (30) is in the unlocked position, wherein the locking element (35) and the bolt (20) are at least partially displaceable into a common insertion space (14) of the housing (12), characterized in that that the bolt (20) is pre-tensioned into the locking position by means of at least two bolt return elements (22), wherein the locking element (35) is arranged between the bolt return elements (22) when viewed in the displacement direction of the yoke (30). Locking device (10) according to claim 1, wherein the at least one locking element (35) is simultaneously designed as a guide element by which the yoke (30) is guided in the housing (12), wherein the locking element (35) preferably has a guide section (36) which is slidably mounted and guided in a guide of the housing (12). Locking device (10) according to one of the preceding claims, wherein the bolt return elements (22) extend perpendicular to the longitudinal axis of the locking element (35) and / or at least partially within the insertion space (14).A locking device (10) according to one of the preceding claims, wherein the bolt (20) is biased into the locking position by means of at least two bolt return elements (22) and / or wherein the bolt return elements (22) are arranged symmetrically to the longitudinal axis of the blocking element (35) when viewed in the direction of displacement of the bolt (20). A locking device (10) according to one of the preceding claims, wherein the yoke (30) is biased into a locking position by means of at least one yoke return element (32) and is preferably displaceable into the unlocking position by means of at least one yoke actuator (34).Vermegelungsvorrichtung (10) according to claim 5, wherein the locking element (35) has a locking section (37) which, in the unlocked position of the yoke (30), projects into a travel path of the bolt (20) within the insertion space (14), wherein the locking element (35) preferably further has a contact section (38) which is connected to or contacted by the at least one yoke actuator (34). A locking device (10) according to claim 5 or 6, wherein two yoke actuators (34) are provided, which are preferably arranged symmetrically to the locking element (35) in the displacement direction of the bolt (20). A locking device (10) according to any one of claims 5 to 7, wherein the yoke return element (32) is a compression spring which is arranged coaxially to the locking element (35) and is preferably partially received in a spring receptacle (39) of the locking element (35) and / or mounted on a spring dome (33) connected to the housing (12). Locking device (10) according to one of claims 5 to 8, wherein the yoke return element (32) is at least partially arranged in the insertion space (14), wherein the bolt (20) preferably has a particularly U-shaped recess (26) on an end face facing the yoke return element (32), which in the unlocked position of the bolt (20) at least partially encloses the yoke return element (32).Locking device (10) according to any one of claims 5 to 9, wherein the yoke actuator (34) and / or the bolt actuator (24) comprises or represents a hydraulic cylinder, in particular a plunger cylinder. Locking device (10) according to any one of the preceding claims, wherein two bolts (20) are provided for locking the telescoping cylinder with a telescoping section, wherein each bolt (20) is associated with at least one locking element (35), in particular exactly one locking element (35), which, viewed in the displacement direction of the respective bolt (20), is arranged between its bolt return elements (22). Locking device (10) according to claim 11 and further developed with the features of claim 2, wherein exactly two locking elements (35) are provided, which function as guide elements, wherein a further guide element (40) is provided, such that the yoke (30) has a total of three Guide elements (35, 40) are guided in the housing, wherein the further guide element (40) is preferably arranged outside a central plane (50) defined by the longitudinal axes of the locking elements (35) and in particular comprises a guide rod (42) connected to the yoke (30), which is slidably mounted and guided in a guide of the housing (12). Adjustment device (10) according to claim 11 or 12, wherein the locking elements (35) are arranged centrally on opposite sides of the yoke (30), wherein the longitudinal axes of the locking elements (35) are preferably arranged in a common plane with the longitudinal axes of the bolts (20).A locking device (10) according to one of the preceding claims and further developed by the features of claims 5 and 11, wherein exactly four yoke return elements (32) are provided, which are arranged axially symmetrically to a central plane (50) spanned by the longitudinal axes of the locking elements (35) and preferably to a plane perpendicular thereto. A locking device (10) according to one of the preceding claims, wherein an end section of the locking element (35) projecting into a travel path of the bolt (20) within the insertion space (14) has an opening (60) on its end face that is completely enclosed by a wall (62), wherein preferably the yoke return element (32) projects from the insertion space (14) through the opening (60) into a spring receptacle (39) of the locking element (35), which is enclosed in particular by the wall (62).Locking device (10) according to the preceding claim, wherein a dome receiving chamber (66) formed within the locking element (35) adjoins the spring receptacle (39), which is designed such that a spring dome (33) extending in the insertion chamber (14), on which the yoke return element is mounted, in an unlocking position of the yoke (30) into the dome. The receiving space (66) protrudes, but the yoke return element (32) is always located outside the mandrel receiving space (66), wherein the mandrel receiving space (66) preferably has a smaller diameter than the spring receptacle (39). Working device, in particular mobile crane, with a telescopic boom comprising several slidably nested telescopic sections, a hydraulic telescoping cylinder for extending and retracting at least one inner telescopic section, and a locking device (10) connected to the telescoping cylinder according to one of the preceding claims.

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