INSPECTION OF DEVICES MOUNTED ON AN ELEVATOR

Abstract

Methods for inspecting a cable mounted device for an elevator are disclosed. The cable mounted device comprises a housing (13), an entry hole (12) for a cable, and an exit hole for the cable, and a cable actuation mechanism inside the housing (13). The method comprises inspecting the cable actuation mechanism using an endoscope. Cable mounted devices having an additional inspection hole in the housing (13) for entry of an insertion tube of an endoscope and the use of an endoscope for the visual inspection of cable mounted devices of an elevator are also disclosed.

Claims

1. A method for inspecting a device mounted on an elevator, the device comprising a housing, an entry hole for a cable, and an exit hole for the cable, and a cable actuation mechanism inside the housing and the method comprising: inspecting the cable actuation mechanism using an endoscope by inserting an insertion tube of the endoscope through the entry hole for the cable or through the exit hole for the cable, wherein the cable is removed from the housing prior to inserting the insertion tube.

2. The method for inspecting according to claim 1, wherein the cable actuation mechanism is a safety mechanism, wherein the safety mechanism is configured to prevent a cable which passes through the safety device from moving when an unsafe condition exists.

3. The method for inspecting according to claim 2, wherein the safety mechanism comprises a first clamp and a second clamp for clamping the cable in between the first and the second clamps, and wherein the method comprises inspecting the first and the second clamps for unusual wear.

4. The method for inspecting according to claim 2, wherein the safety mechanism comprises a centrifugal detection mechanism, the centrifugal detection mechanism comprising a driven roller, and the method comprising inspecting the driven roller for a crescent shape of an external groove of the driven roller.

5. The method for inspecting according to claim 4, wherein the centrifugal detection mechanism comprises a pressure roller for forcing the cable and the driven roller into contact with each other, and the method comprising inspecting the pressure roller for a crescent shape of an external groove of the pressure roller.

6. The method according to claim 4, wherein inspecting the pressure roller and/or driven roller comprises pushing a distal end of the insertion tube through the clamps of the clamping mechanism.

7. The method for inspecting according to claim 1, wherein the cable actuation mechanism is a traction mechanism comprising a traction sheave, and wherein the method comprises inspecting the traction sheave for unusual wear and/or an unusual shape.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0039] FIG. 1 is a perspective view of a fall-arrest secondary safety device of the type that would be viewed internally using an example of a method of inspection.

[0040] FIG. 2a-2c show longitudinal cross-sectional views and a cross-sectional top view of a fall arrest device which may the same or similar to the fall-arrest device shown in FIG. 1.

[0041] FIG. 3 is a photo showing new rollers in a fall-arrest secondary safety device as viewed using an example of a method of inspecting using an endoscope.

[0042] FIG. 4 is a photo showing new jaws in the fall-arrest secondary safety device shown in FIG. 3 as viewed using an example of a method of inspecting using an endoscope.

[0043] FIG. 5 is a photo showing the used rollers of a fall-arrest secondary safety device as viewed using an example of a method of inspecting using an endoscope after 52 hours of use of the rollers.

[0044] FIG. 6 is a photo showing the used rollers of another fall-arrest secondary safety device as viewed using an example of a method inspecting using an endoscope, also after 52 hours of use of the rollers.

[0045] FIG. 7 is a photo showing a missing roller and a wire rope cut into the roller shaft of another fall-arrest secondary safety device as viewed using an example of a method of inspecting using an endoscope.

[0046] FIG. 8 is a photo showing the stuck roller of another fall-arrest secondary safety device, resulting in a wire rope cutting into a drive roller, as viewed using an example of a method of inspecting using an endoscope; and

[0047] FIG. 9 schematically shows a cross-sectional view of a traction mechanism of a service elevator.

DETAILED DESCRIPTION OF EXAMPLES

[0048] As a preliminary matter, it is to be understood that examples of the methods of the present disclosure can be used with a fall-arrest secondary safety device, an example of which is illustrated in FIG. 1. This fall-arrest secondary safety device is an example of a cable mounted device of an elevator. The fall arrest device 10 of FIG. 1 is mounted on wire rope 5 and comprises a housing 13 having an upper wire rope entry 12, an unlocking lever 4 and a sight window 51. The housing further comprises a lower wire rope exit 14. Also indicated in FIG. 1 is an emergency locking lever 38.

[0049] FIGS. 2a-2c schematically illustrate cross-sectional views of a safety device 10 similar to the one shown in FIG. 1. In the interior of the housing of the safety device 10, at least one safety mechanism is provided. The safety mechanism acts on the wire rope, and therefore may be subject to wear. In particular, the parts and components that are substantially constantly in contact with the wire rope may be subject to wear.

[0050] FIG. 2b illustrates an entry hole 12 for a wire rope. The wire rope passes in between the clamping jaws of upper clamp 6 and lower clamp 7. In normal operation, the clamping jaws are open, and there is substantially no contact between the wire rope and the clamping jaws. The jaws are in normal operation prevented from closing by blocking element 59. If in operation, an overspeed of the wire rope is detected, the overspeed detector trips which moves the blocking element and allows the jaws to close. The elevator is thus prevented from falling.

[0051] The overspeed detection and trip mechanism may comprise a driven roller 48 which is in contact with the wire rope. As the wire rope moves, the roller 48 is driven and rotates. The driven roller 48 is operatively coupled with the centrifugal overspeed detector 55 shown in FIG. 2a. Both the driven roller 48 and the overspeed detector 55 may be mounted on the same axle of shaft.

[0052] The overspeed detector 55 may comprise a plurality of weights 53, which are configured to move outwards as the detector rotates due to the centrifugal forces acting on them. If the driven roller rotates too fast (i.e. this may indicate an unsafe condition caused by e.g. a traction hoist malfunction and/or electromagnetic brake malfunction), the weights 53 move outwardly to such an extent that the detector trips. When the detector trips, as explained before, the clamping jaws close down and the elevator comes to a halt.

[0053] In order to ensure that the driven roller 48 is in fact driven by the movement of the wire rope, a pressure roller 50 may force both of them in contact with each other. Both the pressure roller 50 and the driven roller 48 are constantly in contact with the tensioned wire rope. The contact between the wire rope and the rollers may result in wear of the grooves along the perimeters of the rollers. Instead of a rounded shape (such as shown in FIG. 2c), a crescent shape of the grooves may result.

[0054] In accordance with standard inspection procedures, the procedure comprises the step of removing the wire rope from the attachment point below the service lift thereby creating slack in the system. This wire rope is then slowly moved through the fall-arrest secondary safety device while the centrifugal unit of the fall-arrest secondary safety device is visually inspected through the sight window 51 (shown in FIG. 1). If the centrifugal unit is not spinning, the unit is rejected and must be replaced. The wire rope is then rapidly moved through the fall-arrest secondary safety device. The clamping mechanism of the fall-arrest secondary safety device should be triggered and engage on the wire. If this does not occur, the unit is rejected and must be replaced.

[0055] In accordance with an example, the method comprises the step of removing the wire rope from the fall-arrest secondary safety device. Using the upper wire rope entry 12, the camera and light portion of an 8.4 mm endoscope may be introduced to visualize the wear condition of the jaws 8, 9. The jaws 8, 9 are viewed for any signs of unusual wear. The entire length of each jaw 8, 9 may be viewed. If the shape is not found to be correct, the unit is rejected and must be replaced.

[0056] Moving downwardly, the camera and light portion of an 8.4 mm endoscope may be pushed past the jaws 6, 7 for viewing of the rollers 48, 50. The user may inspect whether both rollers 48, 50 are present, and check whether the shape of the grooves accommodating the wire rope is crescent rather than round, and check whether wear is even on both surfaces. If the shape is not found to be correct, or if any unusual wear is detected, the unit is rejected and must be replaced.

[0057] After the inspection in accordance with examples of the disclosure, the wire rope may be replaced or repositioned in the fall-arrest secondary safety device. The service lift may be raised (about 1 meter) above the deck and the fall-arrest secondary safety device may be manually tripped. An audible snapping sound should be heard. The electromagnetic brake in the service lift is then released. The lift shall not move downward. If the lift moves downward, the fall-arrest secondary safety device is rejected and must be replaced.

[0058] Lastly, the wire rope may be re-secured below the lift per the manufacturer's manual.

[0059] In the above described example, an 8.4 mm endoscope was used. The term 8.4 mm herein refers to the diameter of the insertion tube. It will be clear that the type of endoscope and its size may be chosen in accordance with the safety device to be inspected.

[0060] FIGS. 3-8 show images that may be obtained when using an endoscope for inspection of a fall arrest device as illustrated in FIGS. 1 and 2. FIGS. 3 and 4 show photos of newly installed pressure and driven rollers and new clamping jaws of a fall arrest system. In FIG. 3, the round shape of a portion of the groove accommodating the wire rope along the perimeter of the rollers may be seen.

[0061] FIGS. 5 and 6 are photos showing the rollers of different fall-arrest secondary safety device as viewed using an example of a method of inspecting using an endoscope after 52 hours of use of the rollers.

[0062] FIGS. 7 and 8 are photos showing examples of wear: in the case of FIG. 7, one of the rollers is missing and as a result, the wire rope has cut into the axle on which the roller is mounted. In the case of the fall arrest device of FIG. 8, one of the rollers got stuck, resulting in the wire rope cutting into a drive roller.

[0063] Notably all images shown in FIGS. 3-8 were obtained with examples of methods of inspecting according to the present disclosure. The images clearly illustrate the possibility and viability of inspections being carried out with endoscopes.

[0064] FIG. 9 schematically illustrates a cross-sectional view of a traction hoist 80 for a service elevator. Reference sign 12 indicates an entry hole for a wire rope.

[0065] The wire rope passes completely around the traction sheave 70 and then exits the traction hoist at the bottom of the housing. The cable guide 72 and pressure rollers 74 and 76 ensure that the wire rope maintains contact with the traction sheave along the entire perimeter of the traction sheave 70. Also shown in FIG. 9 is an overload detector 78.

[0066] An electric motor may drive the traction sheave 70 through a gear system involving one or more stages. As the sheave is rotated, it climbs or descends the wire rope. The elevator thus moves upwards or downwards.

[0067] The rollers 74, 76 and sheave 70 are substantially constantly in contact with the tensioned wire rope. The grooves of the rollers and sheave 70 may thus show similar symptoms of wear as previously commented with respect to the fall arrest secondary safety device.

[0068] As was previously explained, an endoscope may be used for inspecting the mechanism that acts on the wire rope. In particular, the rollers 74 and 76 may be checked for a crescent shape of the groove guiding the wire rope, or any other symptom of unusual wear. Also the traction sheave 70 may check for such symptoms. Also the exit hole for the wire rope could be used to allow access to an endoscope.

[0069] In further examples of the present disclosure, a traction device (e.g. traction hoist) or a safety device according to any of the examples described herein may be provided with an inspection hole (different from entry and exit holes of the wire it is mounted on) for insertion of a tube of the endoscope. In examples, the service hole may be provided e.g. in an upper surface of the housing and may be covered with a suitable lid when functioning normally.

[0070] During an inspection, the lid may be moved and an insertion tube may enter though such an inspection hole. E.g. from the top surface of the housing of a fall arrest secondary safety device, relatively easy access may be available to the clamping jaws.

[0071] Additionally, or alternatively, such an inspection hole may be provided at a bottom surface of the housing of the fall-arrest secondary safety device. From such an inspection hole, relatively easy access may be available for checking a centrifugal roller arrangement.

[0072] The size of a dedicated inspection hole may be adapted to the endoscope that is foreseen to be used for inspection.

[0073] Although only a number of examples have been disclosed herein, other alternatives, modifications, uses and/or equivalents thereof are possible. Furthermore, all possible combinations of the described examples are also covered. Thus, the scope of the present disclosure should not be limited by particular examples, but should be determined only by a fair reading of the claims that follow.