BEND TEST APPARATUS FOR A HYDRAULIC HOSE

Abstract

Bend test apparatus (100) for a hydraulic hose (200), the apparatus (100) comprising a main rack (10), at least one sliding rail (11) extending in a longitudinal direction (L) and a carriage (13) which is slidable on the sliding rail (11) in the longitudinal direction (L) and which can be displaced by an actuator (20), wherein the apparatus (100) further comprises a first fixture (1) that is rigidly attached to the main rack (10) to retain a first end (201) of the hydraulic hose (200) and a second fixture (2) that is rigidly attached to the carriage (13) to retain a second end (201) of the hydraulic hose (200), and wherein the apparatus (100) comprises a load cell (30) that is attached between the carriage (13) and the actuator (20) so as to detect a force (F) which is applied via the actuator (20) onto the carriage (13) and thereby onto the hydraulic hose (200) in the longitudinal direction (L).

Claims

1.-7. (canceled)

8. Bend test apparatus for a hydraulic hose, the apparatus comprising a main rack, at least one sliding rail extending in a longitudinal direction and a carriage which is slidable on the sliding rail in the longitudinal direction and which can be displaced by an actuator, wherein the apparatus further comprises a first fixture that is rigidly attached to the main rack to retain a first end of the hydraulic hose and a second fixture that is rigidly attached to the carriage to retain a second end of the hydraulic hose, and wherein the apparatus comprises a load cell that is attached between the carriage and the actuator so as to detect a force which is applied via the actuator onto the carriage and thereby onto the hydraulic hose in the longitudinal direction.

9. Apparatus according to claim 8, wherein the bend test apparatus comprises a displacement sensor that is arranged to measure a displacement of the carriage along the sliding rail in the longitudinal direction.

10. Apparatus according to claim 9, wherein the bend test apparatus comprises a controller adapted to process the force detected by the load cell and/or the displacement measured by the displacement sensor.

11. Apparatus according to claim 8, wherein the controller is further adapted to control the actuator.

12. Apparatus according to claim 11, wherein the controller is further adapted to iteratively record a dataset comprising at least the instantaneous displacement and the corresponding instantaneous force, preferably as a basis for a force vs displacement diagram.

13. Apparatus according to claim 8, wherein the actuator is a linear servo motor.

14. Apparatus according to claim 8, wherein the sliding rail and the carriage are part of a pulley-belt system that is actuated by the actuator.

Description

[0013] In the following, embodiments of the invention will be described with reference to drawings.

[0014] FIG. 1 shows a bend test apparatus 100 for a hydraulic hose 200. The apparatus 100 comprises a main rack 10, two parallel sliding rails 11 extending in a longitudinal direction L and a carriage 13 which is slidable on the sliding rails 11 in the longitudinal direction L.

[0015] The carriage 13 can be displaced by an actuator 20, which is provided as a linear servo motor.

[0016] The apparatus 100 further comprises a first fixture 1 that is rigidly attached to the main rack 10 to retain a first end 201 of the hydraulic hose 200. The first fixture 1 includes a clamp for clamping the first end 201 of the hydraulic hose 200 rigidly to the main rack 10 (see detail in FIG. 1B). The apparatus 100 also comprises a second fixture 2 that is rigidly attached to the carriage 13 to retain a second end 202 of the hydraulic hose 200. The second fixture 2 includes a clamp for clamping the second end 202 of the hydraulic hose 200 rigidly to carriage 13. By displacing the carriage 13—and thereby second fixture 2—the towards first fixture 1 in the longitudinal direction L the hydraulic hose 200 is increasingly bent.

[0017] Furthermore the apparatus 100 comprises a load cell 30 that is attached between the carriage 13 and the actuator 20 so as to detect a force F which is applied via the actuator 20 onto the carriage 13 and thereby onto the hydraulic hose 200 in the longitudinal direction L. The arrangement of the load cell can be seen in more detail in FIG. 1A.

[0018] As can be seen from FIG. 1 the bend test apparatus 100 also comprises a displacement sensor 40 that is arranged to measure a displacement D of the carriage 13 along the sliding rail 11 in the longitudinal direction L. The displacement sensor 40 is integrated in the actuator 20. Alternatively, for example if the sliding rail 11 and the carriage 13 are part of a pulley-belt system (not shown) displacement sensor can be integrated in the pulley-belt system.

[0019] Also, the apparatus 100 comprises a controller 50 adapted to process the force F detected by the load cell 30 and the displacement D measured by the displacement sensor. Furthermore, the controller 50 is adapted to control the actuator 20. Specifically, the controller 50 is capable adapted to iteratively record a dataset comprising the instantaneous displacement D and the corresponding instantaneous force F as a basis for a force F vs displacement D diagram GR.

[0020] In the following an exemplary procedure for operating the apparatus 100 of FIG. 1.

[0021] A hydraulic hose 200 to be tested is prepared at the length of [Pi*(half bend radius)+800 mm]. The hydraulic hose 200 is assembled to the apparatus 100 from both with a fixing length of 400 mm from each side (i.e. from the first fixture 1 and the second fixture 2 respectively). The apparatus 100 is set with zero force input applied on the hydraulic hose 200 from the free end (i.e. from second fixture 2 that is rigidly attached to the carriage 13). A desired amount of force F or/and displacement D is provided to the controller 50 to deform the hydraulic hose 200 from free state. The servo actuator 20 applies minimum force F required to deform the hydraulic hose 200 from at every specific time interval defined with a step by step loop function until the desired amount of displacement D or force input F is reached. The controller 50 records the data read from the actuator 20 and the displacement sensor 40 and simultaneously generates force vs displacement diagram GR as the apparatus 100 operates.

LIST OF NUMERALS

[0022] 1 first fixture [0023] 2 second fixture [0024] 10 main rack [0025] 11 sliding rail [0026] 13 carriage [0027] 20 actuator [0028] 30 load cell [0029] 40 displacement sensor [0030] 50 controller [0031] 100 bend test apparatus [0032] 200 hydraulic hose [0033] 201 first end of hydraulic hose [0034] 202 second end of hydraulic hose [0035] D displacement [0036] F force [0037] GR force vs displacement diagram [0038] L longitudinal direction