Hydraulic unit with pull-out protection

Abstract

The present invention relates to a hydraulic unit (1) comprising a hydraulic component (2), a hydraulic line (3), and a pull-out protection device (4). The hydraulic line (3) includes a hydraulic hose (5) and a fitting (6) attached thereto, which is connected to a hydraulic port (7) of the hydraulic component (2). The pull-out protection device (4) comprises a cable (9), a cable clamp (10), and a clamping body (11) and engages the hydraulic hose (5) by means of a cable loop (12) of the cable (9), formed by the cable clamp (10) and the clamping body (11), which wraps around the hydraulic hose (5). The cable clamp (10) has an end bore (17) into which one of the two cable ends (18) of the cable (9) is inserted and radially crimped.Furthermore, the rope clamp (10) includes a slot (20) that receives a section (22) of the rope (9), such that a rope loop (12) is formed between the section (22) of the rope (9) received in the rope clamp (10) and the rope end (18) crimped in the rope clamp (10), which encircles the hydraulic hose (5). The rope clamp (10) also has a fixing bore (23) that extends transversely through the slot (20) and is suitable for receiving the clamping body (11). When the clamping body (11) is received in the fixing bore (23), the section (22) of the rope (9) received in the slot (20) is positioned between the rope clamp (10) and the clamping body (11).

Description

The present invention relates to a hydraulic unit comprising a hydraulic component having a hydraulic connection, a hydraulic line connected to the hydraulic connection, and a pull-out protection device. The hydraulic line includes a hydraulic hose and a fitting attached thereto, which is connected to the hydraulic connection of the hydraulic component. The pull-out protection device comprises a cable and engages the hydraulic hose by means of a loop of the cable encircling the hydraulic hose. A pull-out protection device can save lives by limiting the consequential damage caused by the hydraulic hose tearing away from the rest of the hydraulic unit. A hydraulic line in a hydraulic unit is often subjected to extremely high operating pressures well over 300 bar. If a hydraulic hose tears from the associated hydraulic component (or from the rest of the hydraulic unit) at such pressures, the loose end of the hose whips around at high speed, spraying out hydraulic fluid under high pressure, possibly even hot. Bystanders can be seriously injured by both the whipping hose end and the spraying (hot) hydraulic fluid. Even though such accidents are thankfully very rare, it cannot be completely ruled out that a hydraulic hose might tear off the rest of the hydraulic unit during operation. A pull-out safety device (also called a safety cable) is a simple way to mitigate the danger of a hydraulic hose breaking off. A pull-out protection device typically has a (wire) rope which is attached (tied) to both the hydraulic hose and the hydraulic unit or fitting, thus acting on both of these components. The attachment of the pull-out protection to the hydraulic hose is often achieved by a rope loop encircling the hydraulic hose, which is formed and fixed (secured) by a rope clamp and a corresponding clamping body. If the hydraulic hose tears away from the hydraulic unit, the anti-theft device prevents the hose from whipping around unchecked, as the hose's range of motion is limited by the wire rope – similar to a dog on a leash. This limits consequential damage and reduces the risk to life and limb. Hydraulic units with pull-out protection devices of the type described above have been in practical use for many years. It has proven advantageous if a pull-out protection device can be installed without having to disconnect the hydraulic hose from the hydraulic component. Furthermore, for safety reasons, a pull-out protection device should be designed in such a way that the probability of incorrect installation is as low as possible and that an installed pull-out protection device cannot be subsequently tampered with. Previously known pull-out protection devices differ essentially in the way the rope loop, by means of which the connection to the hydraulic hose is made, is formed and fixed. European patent EP 4 078 003 B1, filed by the applicant, describes a pull-out protection device in which a rope loop is formed by first threading two sections of wire rope parallel to each other into a clamping block. Subsequently, a rivet is driven between the two parallel wire rope sections perpendicular to their longitudinal extent, thereby clamping the wire rope sections in the clamping block and fixing (securing) the rope loop. The pull-out protection device described in US patent US 111,116,27 B1 also uses a clamping block that can accommodate two parallel wire rope sections. However, the wire rope sections are not clamped in the block with a rivet, but rather with a setscrew. Document US 5,035,126 A discloses a latch for securing the door of an animal cage, comprising a metal cylinder with an open end featuring an internal thread and an opposing end with a slot for receiving and holding the end of a cable that can be inserted into the slot. By screwing a setscrew into the open end of the metal cylinder, the cable inserted into the slot can be clamped there. Australian patent application AU 2021106744 A4 describes a pull-out protection device for securing a hose with a wire rope. At one end of the wire rope, a threaded fork end is formed, from which two prongs extend. The outer surfaces of these prongs are curved and threaded to accept a nut. The facing inner surfaces of the prongs form a gap larger than the diameter of the wire rope. The wire rope, inserted into the gap between the prongs, can be clamped by the nut mounted on the fork end. Against the background of this prior art, the present invention is based on the objective of providing a hydraulic unit with a pull-out protection of the type described above, which is characterized by improved practicality, in particular with regard to reliability, economy and the simplest possible assembly. This problem is solved by the hydraulic unit according to the invention as per claim 1. Particularly advantageous embodiments are listed in the dependent subclaims. The hydraulic unit according to the invention comprises a hydraulic component having a hydraulic connection, a hydraulic line connected to the hydraulic connection, and a pull-out protection device, wherein: - the hydraulic line has a hydraulic hose and a fitting joined thereto, which is connected to the hydraulic connection of the hydraulic component; - the pull-out protection device has a rope, a rope clamp, and a clamping body and engages the hydraulic hose by a rope loop of the rope, formed by the rope clamp and the clamping body, encircling the hydraulic hose; characterized in that: - the rope clamp has an end bore into which one of the two rope ends is inserted and radially crimped; - the rope clamp has a slot; - the slot of the rope clamp receives a section of the rope.so that a rope loop forms between the section of rope received in the rope clamp and the rope end crimped in the rope clamp, which encircles the hydraulic hose; the rope clamp has a fixing bore that penetrates the slot transversely and is suitable for receiving the clamping body; and, with the clamping body received in the fixing bore, the section of rope received in the slot is arranged between the rope clamp and the clamping body. The invention is based on the realization that, through the synergistic combination of the features according to the invention, a hydraulic unit with a pull-out protection device can be realized which is characterized by a number of advantages that, taken together, lead to improved practicality: Low number of components of the pull-out protection device According to the invention, the rope clamp fulfills a dual function: Firstly, a rope end is fixed in the rope clamp by pressing it into the end bore (in particular by means of a radial press). Secondly, the rope loop is formed by means of the rope clamp by threading a section of the rope into the slot of the rope clamp and arranging (i.e., fixing or clamping) it there between the rope clamp and the clamping body. The connection of the pull-out protection cable to the hydraulic hose therefore only requires two components - the cable clamp and the clamping body - which reduces the manufacturing effort. In contrast, prior art typically requires additional components. Particularly in pull-out protection systems, where two rope sections run parallel to each other in a clamping block and are clamped there, an additional component prevents the rope (or the rope end) from slipping through the clamping block. This is typically achieved by pressing a rope stopper onto the rope end, which has a significantly larger diameter than the wire rope and thus prevents the rope from slipping through the clamping block. Using existing tools The fitting is typically joined to the hydraulic hose by pressing it together using a radial press. As part of repair work, this crimping of fittings and hydraulic hoses to form a new hydraulic line is often carried out on-site in the field using a mobile radial press. The new hydraulic line then often also needs to be secured with a new pull-out protection device. According to the invention, the mobile radial press – which is already on site – can be used to securely and permanently connect the end of the wire rope to the rope clamp. The clamping body can be mounted using standard tools (screwdriver, wrench). Special tools, such as rivet guns, which always increase the risk of incorrect assembly, are not necessary. Against this background, the simple design of the pull-out protection, the small number of components and the use of tools that are already available can simplify assembly and thus reduce the risk of incorrect assembly, according to the invention. The fully assembled pull-out protection is also well protected against subsequent manipulation: because it is (almost) impossible to remove the rope end pressed into the rope clamp or - especially if a breakaway screw is used as the clamping element - to free the rope from its fixation in the slot of the rope clamp without destroying the pull-out protection and thus visibly damaging it. In the following, some terms used in connection with the invention are explained and defined in more detail: The formulation that the hydraulic hose is joined to the fitting expresses that the hydraulic hose is permanently connected to the fitting, in particular by crimping the hydraulic hose to the fitting using a radial press. The phrase "the fitting is connected to the hydraulic connection" expresses that the fitting is connected to the hydraulic connection, thus establishing a hydraulic connection between the hydraulic hose and the hydraulic component. The fitting and the hydraulic connection are designed as a nipple (plug) and a socket, respectively, thereby forming a (hydraulic) coupling. The anti-tear device engages the hydraulic hose by means of a rope loop, which wraps around the hydraulic hose. The end hole and the fixing hole can each be designed as either a blind hole or a through hole. The wording that a rope end is inserted into the end bore and radially pressed (there) expresses that the rope end is first inserted into the end bore and then the inner diameter of the end bore of the rope clamp is reduced until the rope end is permanently clamped in the end bore. This is done in particular by means of a radial press. The wording that the fixing hole penetrates the slot transversely expresses that the fixing hole runs transversely to the slot plane defined by the slot. According to a first preferred embodiment of the hydraulic unit according to the invention, the end bore is arranged on the end face of the rope clamp and / or the end bore runs parallel to a longitudinal axis of the rope clamp. In this way, it can be achieved that the rope clamp can be inserted particularly easily into a radial press in order to press (clamp) a rope end inserted into the end bore. Advantageously, it can be provided that when the clamping body is inserted into the fixing bore, the section of the rope inserted into the slot is clamped between the rope clamp and the clamping body. Depending on the positioning and diameter of the fixing bore or clamping body, as well as the diameter of the rope, the section of the rope inserted into the slot is either clamped between the rope clamp and the clamping body or arranged there with play. The magnitude of the clamping force transferred from the rope clamp or clamping body to the rope is crucial in determining the force that must be exerted to change the diameter of the rope loop. According to a further advantageous embodiment of the invention, the clamping body is designed as a cylindrical pin, tapered pin, grooved pin or tension pin. Alternatively, the clamping element can be designed as a shear bolt. A shear bolt is typically designed so that its head breaks off from the rest of the bolt as soon as it is fully screwed in and a defined shear torque (transferred from the bolt head to the rest of the bolt) is reached. Once the bolt head has been removed in this way, the bolt can no longer be loosened with a standard wrench or screwdriver, making subsequent manipulation of the bolted joint difficult. The use of standard parts, such as cylindrical pins, taper pins, grooved pins, spring pins or shear bolts, makes it possible to implement a particularly cost-effective pull-out protection. Furthermore, according to another advantageous embodiment, it can be provided that an edge of the slot of the rope clamp facing the end bore of the rope clamp runs perpendicular to the longitudinal axis of the rope clamp, or forms an angle with the longitudinal axis of the rope clamp in the range of 10° to 80°, in particular from 30° to 60° or 40° to 55°. The edge of the slot facing the end bore of the rope clamp (slot edge) limits the extent of the slot and forms the bottom of the slot (slot bottom). By enclosing an angle of 10° to 80° between the slot edge and the longitudinal axis of the rope clamp, a pull-out protection can be achieved, in which the rope loop wraps more tightly around the hydraulic hose or with a larger wrap angle, which is beneficial to reliability and functionality. Manufacturing complexity can be further reduced to an advantage by having the rope clamp have a cylindrical base body. In this way, cost-effective standard parts can be used as raw material (semi-finished product) for the manufacture of the rope clamps according to the invention. Furthermore, it may be provided that the slot (or the slot plane defined by the slot) is designed parallel to the longitudinal axis of the rope clamp and is in particular enclosed by two symmetrical, opposing slot cheeks, and / or the fixing bore is arranged perpendicular to the slot (or to the slot plane). In this way, the manufacturing process can be further simplified. According to a further advantageous embodiment of the invention, the rope clamp has a helical opening that opens into the slot of the rope clamp and through which the rope can be threaded into the slot. Once the rope is threaded through the helical opening into the rope clamp, forces can be transferred directly from the rope to the clamp without having to go through the clamping body. This further increases the stability and reliability of the pull-out protection. Furthermore, it may be provided that the pull-out protection engages the fitting or the hydraulic component. The pull-out protection can engage the fitting or hydraulic component by attaching an additional loop of the rope. This additional loop is formed using another rope clamp and clamping element, similar to the loop that engages the hydraulic hose. Alternatively, the pull-out protection can also engage the fitting or hydraulic component in another way. Furthermore, the slot is advantageously located at the end of the rope clamp that is further away from the end bore. In the following, some embodiments of the invention are explained in more detail with reference to the drawings. Fig. 1A shows a hydraulic unit according to the invention with a pull-out protection device in a schematic top view, Fig. 1B shows the pull-out protection device according to Fig. 1A in a schematic side view, Figs. 2, 3, 4, 5 to 6 each show a rope clamp and a clamping body of a pull-out protection device of an embodiment of the hydraulic unit according to the invention in different views, and Fig. 7 shows a clamping body designed as a grooved pin. With reference to Fig. 1A and Fig. 1B, the general structure of a hydraulic unit 1 according to the invention is explained first, before various embodiments of the pull-out protection are discussed in detail with reference to Fig. 2, Fig. 3, Fig. 4, Fig. 5, Fig. 6 to Fig. 7. The hydraulic unit 1 according to the invention comprises a hydraulic component 2, a hydraulic line 3 and a pull-out protection device 4. The hydraulic line 3 comprises a hydraulic hose 5 and a fitting 6 crimped to it. The hydraulic component 2 has a hydraulic connection 7. The fitting 6 of the hydraulic line 3 and the hydraulic connection 7 of the hydraulic component 2 form two parts of a coupling 8, with the help of which the hydraulic line 3 can be detachably connected to the hydraulic component 2. The pull-out protection 4 comprises a (wire) rope 9 as well as two rope clamps 10, 10.1, 10.2 and two clamping bodies 11, 11.1, 11.2. Each rope clamp 10 and one clamping body 11 form and fix a rope loop 12, 12.1, 12.2 of the rope. The first rope clamp 10.1 and the first clamping body 11.1 form the first rope loop 12.1, which encircles the hydraulic hose 5 and thus engages it. The second rope clamp 10.2 and the second clamping body 11.2 form the second rope loop 12.2, which encloses the hydraulic connection 5 in the area of ​​a circumferential groove 13 and thus engages it. Both rope clamps 10 and both clamping bodies 11 are identical in design. To improve readability, the rope clamp and clamping body will therefore be referred to in the singular, although the descriptions apply to both components. The detailed construction of the rope clamp 10 and the clamping body 11 will first be described with reference to the embodiment shown in Fig. 2. The rope clamp 10 has a cylindrical base body 14 with a longitudinal axis 15. A central end bore 17 is arranged on one end face 16 of the rope clamp 10, running parallel to the longitudinal axis 15 of the rope clamp 10. A rope end 18 of the rope 9 is inserted into the end bore 17, radially crimped there, and thus permanently fixed in the rope clamp 10. At its end furthest from the end bore 17, the rope clamp 10 has a slot 20 defining a slot plane 19. The slot plane 19 is located centrally in the rope clamp 10 and runs parallel to the longitudinal axis 15 of the rope clamp 10. One edge 21 of the slot 20 facing the end bore 17, i.e., the slot base, runs perpendicular to the longitudinal axis 15 of the rope clamp 10. The slot 20 is enclosed by two symmetrical, opposing slot walls 20w. As intended, the slot 20 of the rope clamp 10 receives a section 22 of the rope 9, so that the rope loop 12 is formed between the section 22 of the rope 9 received in the rope clamp 10 and the rope end 18 crimped in the rope clamp 10, which encircles the hydraulic hose 5 (or the hydraulic connection 7). The rope clamp 10 further comprises a fixing bore 23 that penetrates the slot 20 transversely, is arranged perpendicular to the slot plane 19, and is suitable for receiving the clamping body 11. In the embodiment according to Fig. 2, the clamping body 11 is designed as a shear bolt 24, the hexagonal screw head 25 of which shears off when a certain torque is reached. A section 26 of the fixing bore 23 has an internal thread 28 corresponding to an external thread 27 of the shear bolt 23. When, as intended, the section 22 of the rope 9 is inserted into the slot 20 and the clamping body 11, designed as a shear bolt 24, is screwed into the fixing bore 23 and thus inserted, the section 22 of the rope 9 inserted into the slot 20 is positioned and clamped between the rope clamp 10 and the clamping body 11. A marking 30 is engraved on one flank 29 of the cylindrical base body 14 of the rope clamp 10. The rope clamps 10 and clamping bodies 11 shown in Figures 3, 4, 5 to 6 are described in more detail below. To avoid repetition as much as possible, only the essential differences compared to the rope clamp 10 and clamping body 11 according to Figure 2 are discussed. The rope clamp 10 according to Fig. 3 differs from that according to Fig. 2 by the clamping body 11 used. While according to Fig. 2 the clamping body is designed as a shear bolt 23, in the embodiment according to Fig. 3 a cylindrical pin 31 is used. The cylindrical pin 31 has two sections 32 with different cylinder diameters. The fixing bore 23 is adapted to the cylindrical pin 31 used and therefore has two corresponding sections 26 with different bore diameters. The fixing bore 23 is designed as a blind bore, not a through bore. The rope clamp 10 according to Fig. 4 differs from that according to Fig. 2 essentially in that the edge 21 of the slot 20 facing the end bore 17, i.e. the slot base 21, does not run perpendicular to the longitudinal axis 15 of the rope clamp 10, but at an angle w of 54°. Furthermore, the fixing bore 23 is arranged off-center with respect to the longitudinal axis 15 of the rope clamp 10. Moreover, the slot 20 does not extend completely through the rope clamp 10 transversely to the longitudinal axis 15, but ends in the region of the cylinder axis (longitudinal axis 15) of the cylindrical base body 14. The rope clamp 10 according to Fig. 5, however, differs from that according to Fig. 2 essentially in that it has a helical opening 33 which opens into the slot 20 of the rope clamp 10 and through which the rope 9 can be threaded into the slot 20. The fixing bore 23 is arranged off-center with respect to the longitudinal axis 15 of the rope clamp 10. The rope clamp 10 according to Fig. 6 largely corresponds to the rope clamp according to Fig. 5 and differs only in that a cylindrical pin 31 is used as the clamping element 11 instead of a shear bolt 23. The fixing bore 17 is adapted accordingly to the cylindrical pin 31 used. Fig. 7 shows a clamping body 11 designed as a grooved pin 34. The exemplary embodiments of the rope clamps illustrated above can also be used in combination with the grooved pin 34 if the fixing bore is adapted accordingly. The fixing bore must be provided according to the geometry of the grooved pin. Reference symbol list 1 Hydraulic unit 2 Hydraulic component 3 Hydraulic line 4 Pull-out device 5 Hydraulic hose 6 Fitting 7 Hydraulic connection 8 Coupling 9 (Wire) rope 10, 10.1, 10.2 Rope clamp 11, 11.1, 11.2 Clamping body 12, 12.1, 12.2 Rope loop 13 Groove 14 Base body 15 Longitudinal axis 16 End face 17 End hole 18 Rope end 19 Slot plane 20 Slot 20w Slot cheek 21 Edge, slot bottom 22 Rope section 23 Fixing hole 24 Breakaway screw 25 Screw head 26 Fixing hole section 27 External thread 28 Internal thread 29 Flank 30 Marking 31 Dowel pin 32 Dowel pin sections 33 Through hole 34 Grooved pin w Angle

Claims

Hydraulic unit (1) with a hydraulic component (2) having a hydraulic port (7), a hydraulic line (3) connected to the hydraulic port (7), and a pull-out device (4), wherein: - the hydraulic line (3) has a hydraulic hose (5) and a fitting (6) joined thereto, which is connected to the hydraulic port (7) of the hydraulic component (2); - the pull-out device (4) has a rope (9), a rope clamp (10), and a clamping body (11) and engages the hydraulic hose (5) by forming a rope loop (12) of the rope (9), which is formed by the rope clamp (10) and the clamping body (11), around the hydraulic hose (5); - the rope clamp (10) has an end bore (17) into which one of the two rope ends (18) of the rope (9) is inserted and radially crimped; - the rope clamp (10) has a slot (20) which opens a section (22) of the rope (9) picks up,such that the rope loop (12) is formed between the section (22) of the rope (9) received in the rope clamp (10) and the rope end (18) crimped in the rope clamp (10), which encircles the hydraulic hose (5), - the rope clamp (10) has a fixing bore (23) which penetrates the slot (20) transversely and is suitable for receiving the clamping body (11), and - with the clamping body (11) received in the fixing bore (23), the section (22) of the rope (9) received in the slot (20) is arranged between the rope clamp (10) and the clamping body (11). Hydraulic unit (1) according to claim 1, wherein the end bore (17) is arranged at the end face of the rope clamp (10) and / or runs parallel to a longitudinal axis (15) of the rope clamp (10). Hydraulic unit (1) according to one of the preceding claims, wherein, with the clamping body (11) inserted into the fixing bore (23), the section (22) of the rope (9) inserted into the slot (20) is clamped between the rope clamp (10) and the clamping body (11). Hydraulic unit (1) according to one of the preceding claims, wherein the clamping body (11) is designed as a cylindrical pin (31), tapered pin, grooved pin (34) or spring pin. Hydraulic unit (1) according to one of claims 1 to 3, wherein the clamping body (11) is designed as a shear bolt (24). Hydraulic unit (1) according to one of the preceding claims, wherein an edge (21) of the slot (20) of the rope clamp (10) facing the end bore (17) of the rope clamp (10) runs perpendicular to the longitudinal axis (15) of the rope clamp (10), or forms an angle (w) with the longitudinal axis (15) of the rope clamp (10) in the range of 10° to 80°, in particular from 30° to 60° or 40° to 55°. Hydraulic unit (1) according to one of the preceding claims, wherein the rope clamp (10) has a cylindrical base body (14). Hydraulic unit (1) according to one of the preceding claims, wherein the slot (20) is designed parallel to the longitudinal axis (15) of the rope clamp (10) and is in particular enclosed by two symmetrical, opposing slot cheeks (20w), and / or the fixing bore (23) is arranged perpendicular to the slot (20). Hydraulic unit (1) according to one of the preceding claims, wherein the rope clamp (10) has a helical opening (33) which opens into the slot (20) of the rope clamp (10) and through which the rope (9) can be threaded into the slot (20). Hydraulic unit (1) according to one of the preceding claims, wherein the pull-out protection (4) engages the fitting (6) or the hydraulic component (2). Hydraulic unit (1) according to one of the preceding claims, wherein the slot (20) is arranged at the end of the rope clamp (10) that is further away from the end bore (17).

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