An assembly consisting of a tightening device for screw fasteners and a safety device.

Abstract

To prevent a tightening device from unintentionally jumping out in the event of failure of a threaded bolt to be tightened, while reducing assembly complexity associated with an assembly consisting of the tightening device and a safety device.SOLUTION: A safety device (30) comprises a threaded sleeve (31) and protective arm (32) so that the safety device (30) can prevent a tightening device (11) from jumping out when a threaded bolt breaks. The threaded sleeve (31) is arranged outside a cylinder housing (7), and includes an internal thread (33) for engaging a threaded bolt (1C) adjacent to a threaded bolt (1B). The protective arm (32) is attached to the threaded sleeve (31) and extends above the cylinder housing (7) of the tightening device (11).SELECTED DRAWING: Figure 2

Description

Technical Field

[0001] The present invention relates to an assembly comprising a tightening device for a screw fastener and a safety device assigned to this tightening device, the screw fastener comprising a threaded bolt and a threaded nut located on a support surface, the tightening device comprising a support tube surrounding the threaded nut and located on the support surface, a cylinder housing arranged on an extension of the support tube, a hydraulically driven piston arranged in the cylinder housing so as to be movable along an axis, a replaceable bush which can be conveyed relative to the axis by the piston and which comprises an internal thread for screwing onto the threaded bolt, a support body rotatably arranged in the support tube and connectable to the threaded nut by force or form fit, and relates to an assembly comprising at least these components.

Background Art

[0002] When tightening a screw fastener with a tightening device acting purely axially, a very high axially acting force is applied to the threaded bolt. Today, forces are applied to the material of threaded components that load it up to its elastic limit in a short time. In many tightening processes, the use of 90 - 98% of the rated tensile stress is the norm. In some cases, preloading the threaded bolt beyond the recommended tensile stress is already being considered.

[0003] Despite the continuously improving manufacturability of threaded bolts and the associated quality improvements, during the screwing process with an axial tightening device, in rare cases, the threaded bolt may unexpectedly break or fracture. Various reasons for this can be, for example, inappropriate material properties of the screw material, cracks, defects during the coating process, and corrosion.

[0004] Furthermore, threaded bolts can also break if the replaceable bushing is not properly screwed onto the bolt to be tightened during assembly. This is due to improper thread overlap between the threaded bolt and the replaceable bushing.

[0005] In such cases, the energy stored in the screw fastener until failure is suddenly released. Depending on the amount of force applied and the construction of the screw fastener, this can cause the fastener to be thrown several meters. Normally, if a heavy tool hits a person, there is a risk of life-threatening injury. While it is desirable for assemblers to maintain a sufficiently large safety distance during the increase in pressure in the fastener, this is not always possible for various reasons. Furthermore, it is not possible to accurately predict the "direction of flight" of the tool.

[0006] Protective devices are well known that prevent axially acting fastening devices from flying off when a threaded bolt breaks. For example, German Patent Application Publication No. 102007062615 describes a nut for a threaded fastener. This nut consists of nut halves of equal size in the circumferential direction. Both nut halves are fitted together in a separating plane and guided to be movable relative to each other between an open position and a closed position. The nut halves are pivotable relative to each other and for this purpose are pivotably coupled to each other in a first terminal region. A lever is used to move the nut halves to the closed position relative to each other.

[0007] The nut is positioned and fixed to a threaded bolt adjacent to the threaded bolt to be tightened, and is connected to the tightening device by a break-resistant strap. The length of the strap is as short as possible to minimize the potential displacement in the event of breakage of the threaded bolt to be screwed and the associated tightening device springing out.

[0008] The drawbacks of the proposed design in German Patent Application Publication No. 102007062615 are that, although limited, there is still a possibility that the fastening device may spring out if the threaded bolt to be fastened breaks. The risk of injury remains high if the assembling worker does not maintain a predetermined distance. Worse still, because the fastening device is coupled to the nut, in the event of breakage, the fastening device will cause uncontrolled movement that carries a high risk of injury.

[0009] To prevent the fastening device from popping out, it is actually necessary to screw another additional nut onto another threaded bolt located adjacent to the other side of the fastening device. This nut is also attached to the fastening device by its own strap. This involves substantial additional installation complexity because the nut must be attached to both sides of the fastening device and attached to the fastening device by strap. [Overview of the project] [Problems that the invention aims to solve]

[0010] The object of the present invention is to improve an assembly comprising a fastening device and a safety device in order to prevent the fastening device from unintentionally popping out when the threaded bolt to be fastened is damaged, while reducing the complexity of assembly associated with the assembly comprising the fastening device and the safety device. [Means for solving the problem]

[0011] This objective is achieved by an assembly comprising a fastening device and a safety device having the previously identified features, wherein the components of the safety device are a threaded sleeve and a protective arm, the threaded sleeve being positioned outside the cylinder housing and support tube and having female threads for engaging with a threaded bolt on another threaded fastener adjacent to the threaded bolt, and the protective arm being attached to the threaded sleeve and extending above the cylinder housing of the fastening device.

[0012] In other words, the safety device is configured to prevent uncontrollable ejection of the fastening device by being fixed to a threaded bolt adjacent to the threaded bolt to be screwed, and by a protective arm preferably extending above the end face of the cylinder housing opposite the support tube. It is preferable that the protective arm extends completely above the end face of the cylinder housing opposite the support tube.

[0013] First, the fastening device is mounted and prepared as usual on the threaded bolt to be fastened. Then, the threaded sleeve of the safety device is attached to the threaded bolt of another adjacent threaded fastener, such that the safety device's protective arm extends above the cylinder housing of the fastening device.

[0014] At least the protective arm of the safety device protrudes above the cylinder housing so as to reach the circumferential contour of the cylinder housing. However, preferably the protective arm has a length that extends far beyond the cylinder housing, preferably even beyond the entire circumferential contour of the cylinder housing.

[0015] A threaded sleeve is, for example, an elongated sleeve having at least one end on which a female thread is located. The female thread is complementary to the corresponding threaded bolt and is screwed onto a threaded bolt adjacent to the fastening device, or alternatively, pressed by shape fit onto the threads of a threaded bolt adjacent to the fastening device.

[0016] According to one embodiment, the threaded sleeve comprises at least two segments, which are fitted together in a separating plane and guided to be movable relative to each other between an open position and a closed position, thereby locking the threaded sleeve into a threaded bolt or releasing it in a released position. The segments are swivel-mounted to the threaded sleeve on the side opposite the threaded bolt. If there are two such segments, their swivel axes extend parallel to each other.

[0017] Preferably, at least two segments that are movably guided relative to each other in a locked or unlocked position are locked by a ring that is movable in the direction of the longitudinal axis of the threaded sleeve.

[0018] However, it is also possible to have a larger number of segments, for example, three segments. In this case, the positions of the pivot axes of these segments are adapted to each other according to the number of segments.

[0019] The advantage of this embodiment of the threaded sleeve is that it avoids the time-consuming process of screwing it onto a threaded bolt, requiring only the engagement of the threaded sleeve onto the threaded bolt. This is achieved by manual fitting or pressing. To remove the threaded sleeve from the threaded bolt, the ring is moved to the release position, which in turn allows the segments to expand again and release the threaded bolt.

[0020] After the safety device is installed, even though the protective arm extends above the end face of the cylinder housing, the protective arm preferably has an opening that exposes, or makes clear, the drive portion of the clamping device located below, in order to still access the end face of the cylinder housing and the components located inside the cylinder housing.

[0021] Also, preferably, a shape-fitting plate that is shape-compatible with the end face of the cylinder housing is arranged on the clamping device side of the protective arm. By the shape-fitting plate facing the end face of the cylinder housing, a kind of shape-fitting connection with the cylinder housing is formed. The mutually complementary structures can achieve a certain degree of horizontal and vertical fixation by the shape of the shape-fitting plate fitting the shape of the end face of the clamping device.

[0022] Preferably, the shape-fitting plate extends above the entire end face. In an alternative embodiment, the shape-fitting plate preferably extends only above a part of the end face.

[0023] Despite the shape-fitting plate, in order to obtain access to important operating elements within the cylinder housing, such as the drive part, the shape-fitting plate preferably has an opening that aligns with the opening of the protective arm.

[0024] In practice, a plurality of screw fasteners that should be tightened continuously or retightened are often arranged along the annular flange. The structures of all these screw fasteners are the same, and their screw axes often have the same interval from each other.

[0025] However, in another flange connection, the mutual spacing of the screw fasteners may be different. Within the range of the flange connection, the spacing may have a recognizable difference, although it is certainly small. Even in the case of threaded bolts with different mutual spacings, in order to enable the use of an assembly consisting of a clamping device and a safety device, the protective arm may be attached to a threaded sleeve so that it is adjustable laterally with respect to the axis of the cylinder housing. Therefore, according to the screwing situation, the distance between the clamping device and the threaded sleeve can be adapted according to the spacing of the threaded bolts.

[0026] The protective arm is configured to have, on the threaded sleeve side, for example, a slot extending in the direction of the clamping device from the threaded sleeve. Preferably, the threaded sleeve has a circumferential groove for supporting the protective arm movably in the lateral direction. The threaded sleeve is assembled to the protective arm via the groove so as to be rotatable. Accordingly, the threaded sleeve is supported by the groove of the protective arm so as to be movable like a movable bearing along its longitudinal axis.

[0027] The threaded sleeve may be configured to be rotatable relative to the protective arm about its axis. Thereby, centering of the form-fitting plate with respect to the end face of the cylinder housing and at the same time screwing of the threaded sleeve onto the adjacent threaded bolt become possible.

[0028] In case of breakage of the threaded bolt loaded by the clamping device, the kinetic energy of the clamping device suddenly released due to this breakage is transmitted via the form-fitting plate and the protective arm to the threaded sleeve provided on the adjacent threaded bolt. Preferably, the protective arm and / or the form-fitting plate have a bending strength lower than the bending strength of the threaded sleeve, so that the protective arm and / or the form-fitting plate are deformed under impact. Thereby, the clamping device, the adjacent threaded bolt or the threaded sleeve are protected.

[0029] Adjacent threaded bolts are those immediately adjacent to the threaded bolt on which the fastening device is mounted, or those that are not immediately adjacent. The threaded sleeve may be installed on a threaded bolt with one bolt in between, in which case the length of the protective arm is appropriately adjusted. Increasing the distance between the fastening device and the threaded sleeve and extending the associated protective arm has the positive effect that the latter can absorb significantly more kinetic energy in the form of deformation compared to a shorter protective arm. Thus, the risk of damage to the fastening device, the threaded sleeve, and the threaded bolt on which the threaded sleeve is located is reduced.

[0030] Preferably, the groove is formed in part from a threaded sleeve and in part from an end piece attached to the protective arm side of the threaded sleeve. This end piece is removably attached to the threaded sleeve.

[0031] If a threaded bolt breaks, resulting in deformation of the protective arm and, in some cases, the shape-fitting plate, the end piece can be removed from the threaded sleeve, and the deformed protective arm can be replaced with a new, undeformed protective arm.

[0032] However, it is possible that the protective arm, the shape-fitting plate, and the threaded sleeve have the same or at least comparable bending strength. Therefore, if applicable, when the threaded bolt breaks, the entire safety device will deform and must be replaced as a whole.

[0033] Further means will be described below, along with a description of two preferred exemplary embodiments of the present invention shown in the drawings. [Brief explanation of the drawing]

[0034] [Figure 1] This is a schematic cross-sectional view of a known fastening device based on prior art. [Figure 2] This is a front view of the tightening device and safety device installed on a threaded bolt. [Figure 3] This is a perspective view of the safety device. [Figure 4] This is a front view of a threaded sleeve with an expanded segment according to a second embodiment. [Figure 5] This is a front view of a threaded sleeve with closed segments according to a second embodiment. [Figure 6] This is a partial cross-sectional view of the safety device. [Modes for carrying out the invention]

[0035] According to Figures 1 and 2, each of the multiple screw fasteners comprises, for example, threaded bolts 1A, 1B, and 1C, which consist of a wide bolt head, a shank portion, and a threaded portion, and threaded nuts 3 that are screwed onto the threaded portion of each threaded bolt 1A, 1B, and 1C. The screw fasteners arranged in a row serve to tightly fasten together two machine parts or equipment parts, which are two annular flanges 5 and 6 that are positioned flat relative to each other in Figure 1. In the illustrated configuration, the nuts 3 of the screw fasteners are located on the outer surface of the annular flange 5, which serves as the support surface 5A.

[0036] In addition to the threaded bolts 1A, 1B, and 1C and the respective threaded nuts 3 screwed onto these threaded bolts 1A, 1B, and 1C, other elements, such as other threaded nuts on the faces of the annular flanges 5 and 6 to be fastened, opposite to the threaded nuts 3, may form part of the threaded fastening. Furthermore, additional washers or rings may be used between the nuts 3 and the support surface 5A as part of each threaded fastening.

[0037] Each threaded fastener, for example, the middle of the three illustrated threaded fasteners in Figure 2, is stretched, i.e., lengthened, in the longitudinal direction of the thread under the action of an axial tensile force by the tightening device 11. Thus, the threaded bolt 1B is stretched by the axial tension on the threaded end portion 2 of the threaded bolt 1B that protrudes beyond the threaded nut 3. This stretching applies, in particular, to the shank portion and the threaded portion of the threaded bolt 1B. The tightening force and / or tightening pressure applied by the corresponding hydraulic system may be automatically recorded in a documentation module, if a control and analysis unit is used, and may be available for subsequent testing purposes.

[0038] The tightening device 11 allows the threaded nut 3 to be tightened or retightened while a predetermined preload force is applied to the threaded bolt 1B for a specific period of time. The so-called counter-rotation of the nut 3 is performed by an electric motor drive or manually using a suitable handheld tool, such as a polygonal socket with or without a built-in ratchet mechanism. The tightening torque actually applied to rotate the nut 3 counter-rotate may also be automatically recorded in the documentation module.

[0039] A replaceable bushing 12, centrally and longitudinally movable within the cylinder housing 7 of the fastening device 11, has a female thread 13 at one end. This female thread 13 allows the replaceable bushing 12 to be screwed onto the threaded end portion 2 of a threaded bolt 1B that protrudes beyond the nut 3. In some cases, this screwing may be performed using the aforementioned tools. For this purpose, the replaceable bushing 12 has a drive portion 14 at its other end, opposite to the support surface 5A, located on or within the outer end face 17 of the cylinder housing 7. This drive portion 14 includes a polygonal portion on which a tool can be applied to rotate the replaceable bushing 12.

[0040] During the tightening process, the replaceable bushings 12 screwed onto each threaded bolt 1B are subjected to axial tension by strong hydraulic pressure. This causes the threaded bolt 1B to stretch in its longitudinal direction. Consequently, the lower surface of the nut 3 separates from the support surface 5A. In this state, the nut 3 can be rotated and counter-rotated with relatively little resistance, for example, using the aforementioned handheld tool, until the nut 3 achieves new gap-free contact with the support surface 5A.

[0041] This rotational or rotatable motion can be transmitted to the rotational motion of the threaded nut 3 via the interposed gear mechanism 18 shown in Figure 2.

[0042] The indirect rotation of the nut 3 is performed via a support 16 assembled within the support tube 8 of the fastening device 11. In the embodiments described herein, the support 16 is a rotating sleeve. This rotating sleeve surrounds the nut 3 and has a shape-fitting structure on its inner surface, in particular a hexagonal portion that surrounds the hexagonal portion formed on the nut 3 by shape fitting.

[0043] The support or rotating sleeve 16 is driven by a gear mechanism 18. This gear mechanism 18 is located mostly within a drive housing that is situated outside the support tube 8 of the fastening device 11. To rotate the rotating sleeve 16, the support tube 8 has an opening 28 in the area surrounding where the drive housing with the gear mechanism 18 is located. Thus, the rotating sleeve 16 is driven through the opening 28. Together with the rotating sleeve 16, the gear mechanism 18 forms a device for counter-rotating the nut 3. Naturally, the nut 3 can only be properly counter-rotated during the period of axial extension of the threaded bolt 1B.

[0044] The hydraulic tightening mechanism is enclosed by a pressure-resistant cylinder housing 7. A rigid extension below this cylinder housing 7 forms a support tube 8 that surrounds the threaded nut 3. This support tube 8 may be integrated with the cylinder housing 7 or it may be a separate component, such as a component attached to the cylinder housing 7. The support tube 8 is open at the bottom and its annular lower surface is located on a fixed support surface 5A. The lower surface of the nut 3 is also located on this support surface 5A.

[0045] The cylinder housing 7 is provided with a hydraulic connection 20. Through this hydraulic connection 20, the hydraulic work chamber 21 is connected to an external hydraulic supply source, such as a hydraulic pump, under valve control. A piston 25 is located inside the cylinder housing 7 and is sealed against the inner wall of the cylinder. The piston 25 is positioned inside the cylinder housing 7 so as to be longitudinally movable along the axis A of the threaded bolt 1B. By supplying a hydraulic medium into the hydraulic work chamber 21, the piston 25 rises. This may be done, for example, by applying a load to the piston 25 from above and against the force of a spring 22 acting as a piston return spring. The purpose of this spring 22 is to hold the piston 25 in the basic position in which the hydraulic work chamber 21 has the minimum volume.

[0046] The piston 25 is annular in shape and coaxially surrounds the replaceable bushing 12. The piston 25 has a shoulder or step on its inner edge. This shoulder or step faces away from the support surface 5A and forms the support surface on which the replaceable bushing 12 is located. When a hydraulic pump supplies pressurized fluid into the work chamber 21, the piston 25 rises, and this piston 25 transports the replaceable bushing 12 longitudinally. Thus, the threaded bolt 1B extends longitudinally along axis A.

[0047] The replaceable bushing 12 has a female thread 13 at its bolt-side end for screwing onto each end portion 2 of the threaded bolt 1B. The replaceable bushing 12 has a drive portion 14 at its other end. Through this drive portion 14, the replaceable bushing 12 can be rotated during preparation for the tightening process, thereby allowing it to screw onto the end portion 2 of the threaded bolt 1B.

[0048] For example, the drive unit 14 is accessible through an end face opening 19 provided in the cylinder housing 7 in order to screw the replaceable bushing 12 onto the threaded end 2 using the handheld tool described above.

[0049] If the tightening device 11 is already firmly mounted on the threaded bolt 1B, a safety device 30, which has a threaded sleeve 31 with a protective arm 32, is screwed onto the threaded bolt adjacent to the tightening device 11 before the tightening process. This adjacent threaded bolt is threaded bolt 1C in the illustrated configuration.

[0050] The threaded sleeve 31 consists of an elongated cylindrical body having a continuous hole. At the flange-side end of this cylindrical body, a female thread 33 is formed within the passage hole. This female thread 33 is complementary to the male thread of the threaded bolts 1A, 1B, and 1C, and can therefore be screwed onto these male threads.

[0051] Figures 4 and 5 show a second embodiment of the threaded sleeve 31, which here is shown in a multi-part form. The threaded sleeve 31 has two segments 51 at the end opposite the protective arm 32. These two segments 51 are swivelably mounted by their upper ends to the end of the threaded sleeve 31 on the protective arm 32 side. Each of the two segments 51 is formed on its inner surface complementary to each half of the threaded bolt 1C. To ensure the initial engagement of the segments 51 to the threaded bolt 1C, the two segments 51 are connected to each other by a spring element 53 that presses these two segments 51 toward a closed position. This means that the segments 51 initially expand when the threaded sleeve 31 is pressed against a threaded bolt 1C adjacent to a threaded bolt that has been secured by the fastening device 11. When the threaded sleeve 31 reaches a position suitable for locking, the segments 51 are pulled together again, and the segments 51 surround the threaded bolt 1C by shape fitting, thereby forming a shape-fitted connection with the threaded bolt 1C.

[0052] To ensure a morphologically fitted engagement between the segment 51 of the threaded sleeve 31 and the threads of the threaded bolt 1C, as shown in Figure 5, an axially movable ring 52 is fitted onto the segment 51, which is now aligned with the threaded sleeve 31 in a closed state by the upper, integrated threaded sleeve 31. Thus, the expansion of the threaded sleeve 31 with respect to the threaded bolt 1C and the associated loss of engagement are now prevented and eliminated.

[0053] At the end of the threaded sleeve 31 opposite to the threaded bolt 1C, this end is attached to or assembled to a protective arm 32. This protective arm 32 extends above the fastening device 11 and is indirectly positioned on the end face 17 of the cylinder housing 7. On the fastening device side, a shaped fitting plate 40 is attached to the protective arm 32 toward the end face 17 of the cylinder housing 7. This shaped fitting plate 40 gradually descends toward the end face 17 of the cylinder housing 7 as the threaded sleeve 31 is screwed onto the threaded bolt 1C.

[0054] As shown in Figure 6, the shape fitting plate 40 has a conical region 55 extending in the circumferential direction on the side facing the fastening device 11. This conical region 55 is formed to be complementary to the circumferentially extending chamfered portion 56 (see Figure 1) provided on the end face 17 of the cylinder housing 7. Therefore, when the shape fitting plate 40 is placed on the end face 17 of the cylinder housing 7, a shape fitting is formed between the cylinder housing 7 and the shape fitting plate 40 by the conical region 55, which is complementary to the circumferential chamfered portion 56. Since the conical region 55 and the chamfered portion 56 are complementary to each other, they achieve not only a certain degree of horizontal fixing but also vertical fixing through contact between the shape fitting plate 40 and the end face 17 of the fastening device 11.

[0055] Indeed, in the case of steel, fracture propagation occurs in the air at speeds close to the speed of sound. However, the point of fracture initiation can be found in the subsequent forward motion of the fractured steel piece. Therefore, the fractured steel piece has a horizontal motion component in addition to a vertical motion component with respect to the assembly. Additional horizontal fixing by the mutually complementary conical region 55 and chamfered portion 56 prevents the clamping device 11 from flying out laterally. The potential risk of injury to the assembler is reduced.

[0056] In the rare event of failure or fracture of the threaded bolt 1B to be tightened, the rapidly released kinetic energy of the tightening device 11 is transmitted to the threaded sleeve 31 and ultimately to the threaded bolt 1C by the shape fitting plate 40 and the protective arm 32. Since the protective arm 32 has a lower bending strength than the threaded sleeve 31, the protective arm 32 (and additionally the shape fitting plate 40 as well) deforms under impact. This protects the tightening device 11, the adjacent threaded bolt 1C and / or threaded sleeve 31.

[0057] To ensure access to the drive unit 14 even in the presence of the shape-fitting plate 40 and the protective arm 32, openings 15B and 15A are provided in the shape-fitting plate 40 and the protective arm 32. These openings 15B and 15A are aligned with openings 19 provided in the end face 17 of the cylinder housing 7. Opening 15A is located in the protective arm 32, and opening 15B is located in the shape-fitting plate 40.

[0058] A slot 34 is formed in the protective arm 32, extending horizontally from the threaded sleeve 31 toward the fastening device 11. Inside the slot 34, it is located within a groove 41 that extends around the entire circumference of the threaded sleeve 31. Thus, the threaded sleeve 31 is mounted on the protective arm 32 so as to be rotatable about its longitudinal axis B. This allows for the centering of the shape fitting plate 40 relative to the end face 17 of the cylinder housing 7, and simultaneously enables the threading of the threaded sleeve 31 onto the threaded bolt 1C. To increase the grip of the threaded sleeve 31 during threading, it may be advantageous for the threaded sleeve 31 to have splines or a rubber coating on its outer surface.

[0059] Furthermore, the slot 34 allows for horizontal adjustment of the protective arm 32. This allows for adjustment of the distance Z between the threaded sleeve 31 and the shape fitting plate 40. Thus, the assembly consisting of the fastening device 11 and the safety device 30 is suitable for accommodating different spacings between threaded bolts 1A, 1B, and 1C.

[0060] The groove 41 is formed from a threaded sleeve 31 and an end piece 42 attached to the end of the threaded sleeve 31 on the protective arm side. The upper end of the threaded sleeve 31 forms the lower side surface of the groove 41.

[0061] The end piece 42 has a cylindrical portion that is partially engaged with the threaded sleeve 31. The portion of the end piece 42 that protrudes beyond the threaded sleeve 31 forms the circumferential bottom surface of the groove 41. Further adjacent areas of the portion of the end piece 42 that protrudes beyond the threaded sleeve 31 are again widened to the radius of the threaded sleeve 31. The lower surface of the widened portion of the end piece 42 forms the upper side surface of the groove 41. Thus, the protective arm 32 is assembled by the end piece 42 so as to be movable in the horizontal direction, and is thus assembled to the threaded sleeve 31 so as to be adjustable in the horizontal direction.

[0062] The end piece 42 has a polygonal portion on the side opposite to the threaded sleeve 31 that a tool can be applied to. This polygonal portion is the same shape and size as the polygonal portion provided on the drive unit 14, thereby allowing the same tool used to tighten the replaceable bushing 12 to be applied.

[0063] To prevent sliding or rotation of the end piece 42 relative to the threaded sleeve 31, the cylindrical portion of the end piece 42 is locked to the threaded sleeve 31 and fixed in place by two headless screws 43. Both the threaded sleeve 31 and the end piece 42 have threaded holes 44 that align with each other, thereby forming a fitting by the headless screws 43, ensuring force transmission between the end piece 42 and the threaded sleeve 31 or preventing sliding of the end piece 42 relative to the threaded sleeve 31 when tightened with the aforementioned tool. [Explanation of Symbols]

[0064] 1A Threaded bolt 1B Threaded bolt 1C Threaded bolt 2. Threaded end portion 3. Threaded nuts 5. First flange 5A Support surface of the first flange 6. Second flange 7 Cylinder Housing 8 Support tube 11. Fastening device 12 replaceable bushings 13 Female thread 14. Drive unit 15A Protective arm opening 15B Opening of the shaped mating plate 16 Support 17 End face of cylinder housing 18 Gear mechanism 19. Opening of the drive unit 20 Hydraulic connection 21 Working Chamber 22 springs 25 pistons 28 Aperture 30 Safety equipment 31 Threaded sleeve 32 protective arms 33 Female threads 34 slots 40 Shape-matching plates 41 Groove 42 End piece 43 Headless screws 44 threaded holes 50 separation planes 51 segments 52 rings 53 Spring elements 55 Conical region 56 Chamfered section Axle of the clamping device B Axis of threaded sleeve Z distance

Claims

1. An assembly comprising a tightening device (11) for a screw fastening body and a safety device (30) assigned to the tightening device (11), wherein the screw fastening body comprises a threaded bolt (1B) and a threaded nut (3) located on a support surface (5A), and the tightening device (11) is A support pipe (8) surrounds the threaded nut (3) and is located on the support surface (5A), A cylinder housing (7) is positioned on the extension of the support pipe (8), A hydraulically driven piston (25) is positioned within the cylinder housing (7) so as to be movable along the axis (A), A replaceable bushing (12) that can be transported relative to the axis (A) by the piston (25), the replaceable bushing (12) having an internal thread (13) for screwing onto the threaded bolt (1B), A support (16) is rotatably positioned within the support tube (8) and can be coupled to the threaded nut (3) by force fitting or morphological fitting, In an assembly comprising at least the following: The components of the safety device (30) are a threaded sleeve (31) and a protective arm (32), wherein the threaded sleeve (31) is positioned outside the cylinder housing (7) and the support tube (8) and is configured to have a female thread (33) for engaging with a threaded bolt (1C) adjacent to the threaded bolt (1B), and the protective arm (32) is attached to the threaded sleeve (31) and extends above the cylinder housing (7) of the fastening device (11). An assembly characterized in that a shaped fitting plate (40) that fits the end face (17) of the cylinder housing (7) is positioned on the fastening device side of the protective arm (32), and when the threaded sleeve (31) is screwed onto the adjacent threaded bolt (1C), the shaped fitting plate (40) gradually descends and is placed on the end face (17) of the cylinder housing (7).

2. The assembly according to claim 1, characterized in that the protective arm (32) extends above the end face (17) of the cylinder housing (7) on the side opposite to the support pipe (8).

3. The assembly according to claim 1, characterized in that the shape fitting plate (40) extends above the entire end face (17).

4. The assembly according to claim 1, characterized in that the shape fitting plate (40) extends only above a portion of the end face (17).

5. The assembly according to claim 1 or 2, characterized in that the protective arm (32) has an opening (15A) that exposes the drive portion (14) of the fastening device (11).

6. The assembly according to claim 5, characterized in that the shape fitting plate (40) has an opening (15B) that aligns with the opening (15A) of the protective arm (32).

7. The assembly according to any one of claims 1 to 6, characterized in that the protective arm (32) is attached to the threaded sleeve (31) so as to be adjustable laterally with respect to the axis (A) of the cylinder housing (7).

8. The assembly according to any one of claims 1 to 7, characterized in that the threaded sleeve (31) is rotatable with respect to the protective arm (32) about its longitudinal axis (B).

9. The assembly according to claim 7 or 8, characterized in that the threaded sleeve (31) has a circumferential groove (41) for laterally movable support of the protective arm (32).

10. The assembly according to claim 9, characterized in that the groove (41) is formed from the threaded sleeve (31) and an end piece (42) attached to the end of the threaded sleeve (31) on the protective arm side.

11. The assembly according to any one of claims 1 to 10, characterized in that the adjacent threaded bolt (1C) is either a threaded bolt provided immediately next to the threaded bolt (1B) or a threaded bolt not provided immediately next to it.

12. The assembly according to claim 1, characterized in that the protective arm (32) and / or the shape fitting plate (40) have a bending strength lower than that of the threaded sleeve (31).

13. The assembly according to any one of claims 1 to 12, wherein the threaded sleeve (31) comprises at least two segments (51), the at least two segments (51) are fitted together on a separating plane (50) and guided to be movable relative to each other between an open position and a closed position, and the threaded sleeve (31) is fixed in a locking position to the threaded bolt (1C) or released in a release position.

14. The assembly according to claim 13, characterized in that the at least two segments (51), which are movably guided relative to each other in the locked position or the released position, are locked by a ring (52) which is movable in the direction of the longitudinal axis (B) of the threaded sleeve (31).

Images