Test bench with a quick-release clamping unit

Abstract

The present invention relates to a test bench with a quick-release clamping unit (3) for pressure testing a line (8). The quick-release clamping unit (3) comprises a connection receptacle (11) and a quick-release clamping head (12), between which a connection (10) of the line (8) to be tested can be clamped. The quick-release clamping head (12) has a base body (13), a test adapter (19) movable relative to the base body (13), and a hydraulic force converter (28). The hydraulic force converter (28) comprises a drive unit (22), an input piston (21), and an output piston (20) acting on the test adapter (19). The input piston (21) and the output piston (20) are each guided axially movable along their piston axes (20A, 21A) in the base body (13) and communicate hydraulically with each other by means of a hydraulic fluid (23).By actuating the drive device (22) the input piston (21) moves axially relative to the base body (13), which, by means of the hydraulic fluid (23), causes an axial movement of the output piston (20) and the test adapter (19).

Description

[0001] The present invention relates to a test bench with a quick-release clamping unit for pressure testing a line, in particular a hydraulic line.

[0002] Such test benches for pressurized (hydraulic) lines play a central role in the quality testing of (hydraulic) lines and serve to test the reliability and safety of the lines under realistic operating conditions.

[0003] This typically involves conducting stress tests under high pressure, varying temperatures and / or pulsating loads to ensure that the cables can withstand the requirements in safety-critical applications, for example in aviation, mechanical engineering or the automotive industry.

[0004] Especially when many cables need to be tested in a short time, ease of handling and quick change of the cables to be tested play a crucial role, as lengthy and complicated setup processes can lead to errors and increased costs.

[0005] Against this background, quick-release clamping systems are frequently used to connect the line to be tested to the test bench via its connections during the test.

[0006] A quick-clamping system is characterized by its ability to mechanically fix the connection(s) of the line being tested to the test bench, while simultaneously enabling fast, easy, and safe handling. This fastening (fixing) is typically achieved without tools using lever mechanisms, clamping jaws or spindle drives, pneumatic or hydraulic actuators, or similar clamping devices that engage with a connection of the (hydraulic) line.

[0007] From the extensive body of known prior art, reference is made, by way of example, to CN 221485006 U and CN 214503182 U. Both publications describe a test rig with a quick-release clamping device for pressure testing a hydraulic line. In CN 221485006 U, the quick-release clamping device is fixed to a connection of the hydraulic line by means of a spindle mechanism, while in CN 214503182 U, it is fixed by means of a hydraulic actuator.

[0008] The Chinese utility models CN 2 18 470 406 U and CN 2 13 903 146 U each describe a test stand for pressure testing a pipeline, in which the fittings of the pipeline can be clamped by means of hydraulic cylinders.

[0009] US patent US 5,155,997 A describes a hydraulic force converter. German patent application DE 10 2021 104 601 A1 describes a linear actuator in which a piston, movable linearly via a threaded drive, displaces a hydraulic fluid to achieve linear motion.

[0010] Against this background, the present invention is based on the objective of providing a test bench with a quick-release clamping unit that is characterized by improved practicality, in particular with regard to the ease of handling and quick change of lines to be tested, as well as high reliability and safety.

[0011] This problem is solved by the test bench with a quick-release clamping unit according to claim 1. Preferred embodiments are specified in the dependent claims.

[0012] The test rig according to the invention with a quick-release clamping unit for pressure testing a line, in particular a hydraulic line, is characterized in that - the quick-release unit comprises a connection receptacle and a quick-release head, between which a connection of the line to be tested can be clamped, - the quick-release clamping head comprises a base body, a test adapter movable relative to the base body, and a hydraulic force converter, - the hydraulic force converter comprises a drive unit, an input piston and an output piston acting on the test adapter, - the input piston and the output piston are each guided axially movable (along their piston axis) in the base body and communicate hydraulically with each other by means of a hydraulic fluid, and - by actuating the drive device, the input piston moves axially relative to the base body, which causes an axial movement of the output piston and the test adapter by means of the hydraulic fluid.

[0013] Through the synergistic interaction of the features according to the invention, a test bench can be realized in which the line to be tested can be installed, tested and removed easily, quickly, reliably and safely.

[0014] The invention makes it possible to clamp a connection of a line to be tested, arranged between the connection receptacle and the test adapter of the quick-release clamping head, by actuating the drive device and to seal it tightly with the test adapter in order to subsequently fill the line with a test fluid and test it.

[0015] Clamping can thus be done quickly and easily using only manual force, which not only enables short setup and assembly times, but also benefits occupational safety and the reliability of the test bench.

[0016] The hydraulic force converter, whose input piston has a smaller piston cross-section than the output piston, is a key component that enables the connection of the line to be clamped by the output piston with a relatively large clamping force (output force) between the connection receptacle and the quick-release head, while only a relatively small actuating force (input force) needs to be applied to the input piston.

[0017] The actuating force acting on the input piston is exerted by actuating the drive device. The drive device can be manually or mechanically operated and, in particular, act on the input piston by means of a lever mechanism or a spindle mechanism. The drive device is thus designed to move the input piston along its piston axis.

[0018] The following defines and explains some terms and features used to describe the invention: A line typically comprises a hose or pipe and two fittings attached to its ends. These fittings are often crimped to the hose or pipe using a radial crimping tool. Each fitting consists of a nipple and a crimp sleeve. The nipple is partially inserted into the hose or pipe, while the crimp sleeve encloses the hose or pipe in the area of ​​the inserted nipple. When the diameter of the crimp sleeve is radially reduced by the crimping tool, the hose or pipe is clamped between the crimp sleeve and the nipple, creating a tight seal. Lines can be configured as hydraulic, pneumatic, or gas lines.

[0019] The fitting includes, for example, a plate with a slot-shaped recess positioned between two opposing claw flanks, into which the fitting of the line to be tested can be threaded. The clear width of the recess (i.e., the distance between the two claw flanks) is matched to the fitting so that the fitting, with a flange section (at least in one direction), bears against the fitting and can thus be pressed against it. The fitting can be supported symmetrically to the line under test to distribute the forces symmetrically on both sides. This prevents the fitting from rotating relative to the piston axis of the output piston during pressing, which could lead to unwanted leaks between the test adapter and the fitting.Alternatively or additionally, the test adapter can be attached to the output piston by means of a ball joint to prevent leaks from forming between the test adapter and the connection if the connection mount twists or bends during pressing.

[0020] The inlet piston and the outlet piston each move within a cylinder chamber filled with hydraulic fluid. As one of the pistons penetrates further into its respective cylinder chamber, the corresponding volume of hydraulic fluid is displaced. The two pistons can move within a common cylinder chamber or within two separate cylinder chambers that are fluidically connected. Two cylinder chambers are fluidically connected when, under certain operating conditions or valve positions, a fluid can flow from one cylinder chamber to the other.

[0021] The statement that the inlet piston and the outlet piston communicate hydraulically with each other via the hydraulic fluid expresses the fact that inserting one piston into its respective cylinder causes the other piston to be pushed out of its respective cylinder by the volume of hydraulic fluid displaced. Both pistons are thus hydraulically coupled.

[0022] When the drive mechanism is actuated such that the input piston moves (axially along its piston axis) relative to the base body and penetrates further into the associated cylinder chamber, a certain volume of hydraulic fluid is displaced. Due to the hydraulic coupling of the two pistons (hydraulic communication), this causes an axial displacement of the output piston out of the associated cylinder chamber, corresponding to the displaced volume. The output piston acts on the test adapter and thus also displaces it in the axial direction (relative to the piston axis of the output piston), so that a connection located between the fitting and the test adapter is jammed or clamped there.

[0023] According to a first preferred embodiment of the invention - the inlet piston has an inlet piston cross-sectional area, and - the output piston has an output piston cross-sectional area that is larger than the input piston cross-sectional area.

[0024] If the input piston has a smaller cross-sectional area than the output piston, the force applied to the input piston can be converted by the force converter into a larger output force, which can then be transmitted via the output piston to the test adapter. For example, if the output piston's cross-sectional area is 10 times larger than the input piston's cross-sectional area, the actuating force could be converted into an output force 10 times greater in this way.

[0025] In this context, a piston cross-sectional area is understood to be the area of ​​the end face of a piston facing the hydraulic fluid.

[0026] A particularly easy-to-manufacture, compact and robust force converter can be realized by having the input piston and the output piston each protrude at least partially into a common cylinder chamber filled with hydraulic fluid.

[0027] Furthermore, it can be advantageously provided that the output piston can be reset by means of a reset device, which is in particular designed as a return spring.

[0028] According to a further particularly advantageous embodiment of the test rig according to the invention, the base body of the quick-release clamping head and the connection receptacle are arranged on a frame of the quick-release clamping unit.

[0029] In this way, the connection holder and the quick-release head can be supported on the frame of the quick-release unit during the clamping of the cable connection, in order to exert the required clamping force on the test adapter and the connection.

[0030] It is particularly advantageous if the base body of the quick-release clamping head and / or the connection receptacle is / are arranged on the frame of the quick-release clamping unit in a slidable manner by means of a positioning device, in particular comprising a spindle mechanism.

[0031] Using the positioning device, the test adapter can be quickly moved to the "stop" position against the connection of the line inserted in the connection holder, while the hydraulic force converter is then used to exert the high contact force required for a tight connection.

[0032] A particularly simple and equally robust connection receptacle can be achieved by having two opposing claw flanks and a slot-shaped recess extending between them, into which the connection of the line to be tested can be received.

[0033] Another particularly advantageous embodiment of the invention is characterized in that the test adapter - is designed with a conical shape - has a test fluid channel opening into its end face facing the connection point, and / or - is detachably attached to the output piston.

[0034] A conical test adapter, due to its shape, can be tightly connected to fittings with different inner diameters. The same test adapter can therefore be used to test various cable types with different fittings, thus minimizing changeover times.

[0035] A test fluid can be applied to a line to be tested via the test lead which terminates in its end face facing the connection point.

[0036] The statement that the test adapter is detachably attached to the output piston indicates that the test adapter can be easily replaced with a different one. Since the test adapter typically needs to be matched to the type of cable being tested, it is advantageous if the adapter can be quickly and easily replaced when different cable types need to be tested in a short period of time.

[0037] According to the invention, a section of the inlet piston has an external thread and the base body has a corresponding internal thread, so that by rotating the inlet piston relative to the base body the inlet piston can be linearly displaced.

[0038] Furthermore, it may be provided that the drive mechanism of the input piston - a manually operated drive device, in particular designed as a handle or lever mechanism, and / or - has a mechanical drive device.

[0039] An embodiment of the test rig according to the invention is explained in more detail below with reference to the drawings. This shows Fig. 1 a schematic side view of a test rig according to the invention, and Fig. 2 the quick-release clamping unit of the test rig according to the invention in an enlarged, schematic sectional view.

[0040] The in Fig. The test stand 1 shown according to the invention comprises a test stand frame 2, two quick-release clamping units 3, a test fluid line 4, a filling and pressure generation unit 5 and a control unit 6 with a display unit 7.

[0041] By means of the two quick-release clamping units 3, a line 8 designed as a hydraulic line with a (hydraulic) hose 9 and connections 10 attached to its ends can be fixed fluidically tight in the test rig 1.

[0042] The test fluid line 4 connects the filling and pressure generation unit 5 to one of the two quick-release clamping units 3, hereinafter referred to as filling quick-release clamping unit 3.1. Test fluid can be introduced into the hydraulic line 8 under test via the filling quick-release clamping unit 3.1. The quick-release clamping unit 3, located opposite the filling quick-release clamping unit 3.1 and hereinafter referred to as the sealing quick-release clamping unit 3.2, seals the hydraulic line 8 at its opposite end.

[0043] The filling and pressure generation unit 5 can be actuated by the control unit 6 in such a way that a test fluid is conveyed through the test fluid line 4 via the filling quick-release unit 3.1 into the hydraulic line 8 to be tested.

[0044] The control unit 6 has a user interface through which the test pressure can be set and / or the test process started. The display unit 7 can be used to show, in particular, the pressure present in the hydraulic line 8.

[0045] With regard to Fig. 2 The structure of the filling quick-release unit 3, 3.1 will be explained in more detail below.

[0046] The filling quick-release clamping unit 3.1 comprises a connection receptacle 11, a quick-release clamping head 12 with a base body 13, and a frame 14, which is part of the test stand frame 2. The connection receptacle 11 and the base body 13 of the quick-release clamping head 12 are each fixed to the frame 14.

[0047] The connection receptacle 11 has two opposing claw flanks 15, between which a slot-shaped recess extends, into which one of the two connections 10 of the hydraulic line 8 to be tested is received.

[0048] The in Fig. The connection 10 shown in Figure 2 comprises a connecting nipple 16 and a crimp sleeve 17. The connecting nipple 16 is inserted into the hydraulic hose 9 up to a connecting flange 18. The crimp sleeve 17 encloses the hydraulic hose 9 from the outside in the area of ​​the inserted connecting nipple 16. The crimp sleeve 17, the hydraulic hose 9, and the connecting nipple 16 were pressed together fluidically tight using a radial press.

[0049] The connection flange 18 of the connection 10 is supported on the connection receptacle 11, so that the connection 10 does not move further axially away from the quick-release clamping head 12 (i.e., to the left relative to the Fig. 2) can be postponed.

[0050] The connection flange 18 of the connection 10 is clamped (squeezed) between the connection receptacle 11 and the quick-release head 12.

[0051] The quick-release clamping head 12 comprises, in addition to the base body 13, a test adapter 19, an output piston 20 attached to the test adapter 19, an input piston 21 and a drive device 22 designed as a handle that engages the input piston 21.

[0052] The base body 13 contains a cylinder chamber 24 filled with a hydraulic fluid 23, into which the output piston 20 and the input piston 21 project at least partially. Both pistons 20, 21 are guided axially along their respective piston axes 20A, 21A within the base body 13 and are each sealed against the base body 13 by means of a sealing ring 25. The pistons 20, 21 can thus be pushed further into and out of the cylinder chamber 24. The input piston 20 and the output piston 21 communicate hydraulically with each other via the hydraulic fluid 23 in the cylinder chamber 24; in other words, the two pistons 20, 21 are hydraulically coupled.

[0053] The inlet piston 21 extends along its piston axis 21A, is cylindrical, and has a circular inlet piston cross-sectional area 21S. A section of the inlet piston 21 has an external thread 26, which corresponds to an internal thread 27 in a region of the base body 13. By turning the handle, i.e., by actuating the drive mechanism 22, the inlet piston 21 can be screwed further into or out of the base body 13 and thus into the cylinder chamber 24. The inlet piston 21 is thereby moved axially (along its piston axis 21A) relative to the base body 13.

[0054] If the input piston 21 is screwed further into the cylinder chamber 24 in this manner, the hydraulic fluid 23 displaced in the process causes the output piston 20 to be pushed out of the cylinder chamber 24 by an output force corresponding to the displaced volume. The input piston 21, the output piston 20, and the drive unit 22 are part of a hydraulic force converter 28.

[0055] The output piston 20 extends along its piston axis 20A, is cylindrical, and has a circular output piston cross-sectional area 20S, which is larger than the input piston cross-sectional area 21S. The output piston 20 can be reset by means of a return spring (not shown). During reset, the return spring pushes the output piston 20 further into the cylinder chamber 24.

[0056] The test adapter 19 is interchangeably attached to the output piston 20 and comprises a conical section 29 that tapers to an end face 29S facing the connection receptacle 11. A test fluid channel 30 extends through the test adapter 19, opening into the end face 29S on one side and into the test fluid line 4 on the other. Test fluid can flow through the test fluid channel 30 into the hydraulic line 8 to pressurize it with a test pressure.

[0057] In the Fig. In the clamped state shown in Figure 2, the conical section 29 of the test adapter 19 partially protrudes into the connection 10 of the hydraulic line 8 and is clamped against the connection 10 by the output force acting on the test adapter 19 from the output piston 20, forming a tight connection.

[0058] The quick-release fastener 3, 3.2 is essentially constructed in the same way as the one in Fig.The filling clamping device 3, 3.1 shown in Figure 2, however, does not have a test fluid channel. Reference symbol list 1 test bench 2 test bench frames 3 quick-release units 3.1 Filling quick-release unit 3.2 Quick-release fastener unit 4 test fluid line 5 Filling and pressure generation unit 6 Control unit 7 Display unit 8 (hydraulic) lines 9 (hydraulic) hose 10 connection 11 Connection 12 Quick-release head 13 basic shapes 14 frames 15 Claw flank 16 connecting nipples 17 Press sleeve 18 Connection flange 19 test adapters 20 output pistons 20A Piston axis of the output piston 20S Output piston cross-sectional area 21 input pistons 21A Piston axis of the inlet piston 21S Inlet piston cross-sectional area 22 Drive unit 23 Hydraulic fluid 24 cylinder room 25 sealing ring 26 external threads 27 internal threads 28 hydraulic power converters 29 conical section 29S Front surface 30 test fluid channels

Claims

Test stand (1) with a quick-release clamping unit (3) for pressure testing a line (8), in particular a hydraulic line, wherein: - the quick-release clamping unit (3) comprises a connection receptacle (11) and a quick-release clamping head (12) between which a connection (10) of the line (8) to be tested can be clamped; - the quick-release clamping head (12) comprises a base body (13), a test adapter (19) movable relative to the base body (13), and a hydraulic force converter (28); - the hydraulic force converter (28) comprises a drive unit (22), an input piston (21), and an output piston (20) acting on the test adapter (19); - the input piston (21) and the output piston (20) are each guided axially movable along their piston axis (20A, 21A) in the base body (13) and communicate hydraulically with each other by means of a hydraulic fluid (23); - the input piston is moved by actuating the drive unit (22). (21) moved axially relative to the base body (13),which causes an axial movement of the output piston (20) and the test adapter (19) by means of the hydraulic fluid (23), and - a section of the input piston (21) has an external thread (26) and the base body (13) has a corresponding internal thread (27), so that by rotating the input piston (21) relative to the base body (13) the input piston (21) can be linearly displaced. Test rig (1) according to claim 1, wherein - the inlet piston (21) has an inlet piston cross-sectional area (21S), and - the outlet piston (20) has an outlet piston cross-sectional area (20S) which is larger than the inlet piston cross-sectional area (21S). Test rig (1) according to one of the preceding claims, wherein the inlet piston (21) and the outlet piston (20) each project at least partially into a common cylinder chamber (24) filled with the hydraulic fluid (23). Test rig (1) according to one of the preceding claims, wherein the output piston (20) can be reset by means of a reset device, which is in particular designed as a return spring. Test rig (1) according to one of the preceding claims, wherein the base body (13) of the quick-release head (12) and the connection receptacle (11) are arranged on a frame (14) of the quick-release unit (3). Test rig (1) according to claim 5, wherein the base body (13) of the quick-release clamping head (12) and / or the connection receptacle (11) is / are each arranged displaceably on the frame (14) of the quick-release clamping unit (3) by means of a positioning device, in particular comprising a spindle mechanism. Test stand (1) according to one of the preceding claims, wherein the connection receptacle (11) has two opposing claw flanks (15) and a slot-shaped recess extending between them, into which the connection (10) of the line (8) to be tested can be received. Test stand (1) according to one of the preceding claims, wherein the test adapter (19) is conically designed, has a test fluid channel (30) opening into its end face (29S) facing the connection receptacle (11), and / or is detachably attached to the output piston (20). Test rig (1) according to one of the preceding claims, wherein the drive device (22) of the input piston (21) comprises a manually actuated drive device (22) in particular designed as a handle or lever mechanism, and / or a mechanical drive device.

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