Overspeed governor for elevator

Abstract

An overspeed governor (1) for an elevator, comprising: a sheave (2) and a cam (4) mounted on one side so as to rotate together with the sheave (2); a pendulum member (5) mounted on the frame (25) so as to rotate about a pivot point (6) and provided with a tripping pawl (8); a cam driven wheel (3) mounted on the pendulum member (5) so as to follow the contour of the cam (4) when the sheave (2) rotates, and starting to jump at intervals when the rotational speed of the sheave (2) is greater than a first rotational speed; a plurality of engaging portions (9) arranged on one side of the sheave (2) so as to rotate together with the sheave (2), the engaging portions (9) and the pendulum member (5) being arranged such that the tripping pawl (8) engages one of the engaging portions (9) when a second rotational speed of the sheave (2) is reached; a main resistance element (23) mounted between the frame (25) and the pendulum member (5); at least one additional resistance element (12) acting on the pendulum member (5) starting from a third intermediate rotational speed of the sheave (2).

Description

Technical Field

[0001] The present invention relates to an overspeed governor for an elevator and an elevator comprising the overspeed governor. Background Art

[0002] An overspeed governor is a safety device that is activated if the speed of the elevator exceeds the limit, ensuring the safety of the people in the elevator car. If the car exceeds its rated speed during ascent or descent, the overspeed governor is triggered and stops the car. Therefore, the overspeed governor is a vital and indispensable product for passenger safety. For this reason, the European directive EN 81 20 / 50 requires the use of overspeed governors on ropeways.

[0003] Latching overspeed governors are known. Latching governors are usually equipped with a pendulum member having a roller that is forced to move along a cam. The cam rotates with the groove wheel, and the governor rope slides on the groove wheel. The pendulum member is provided with a trip pawl. Usually, latching governors are equipped with a tension spring that acts against the centrifugal force of the trip pawl. This centrifugal force is caused by the movement of the roller along the cam. Once the centrifugal force is higher than the spring force, the trip pawl will begin to disengage after each fluctuation of the cam as long as the contact switch can be triggered (contact speed). Further acceleration of the groove wheel leads to a higher disengagement distance until the trip pawl cannot leave the groove wheel quickly enough and trips with the latch on the groove wheel (trip speed). The groove wheel is then blocked by the trip pawl and the governor rope slides over the pulley.

[0004] However, the spring force and the centrifugal force increase almost linearly, so when a fault is about to occur, the time elapsed between the fault-free state and the fault state is negligible. Summary of the invention

[0005] In this context, the technical task of the present invention is to provide an overspeed governor for an elevator and an elevator comprising such an overspeed governor which overcomes the above-mentioned shortcomings of the prior art.

[0006] In particular, an object of the invention is to provide an overspeed governor for elevators which is safer than previous solutions.

[0007] Another object of the present invention is to provide an overspeed governor for elevators which is universal and easily adaptable to different requirements.

[0008] The technical task and the specified purpose are substantially achieved by an overspeed governor for an elevator, the overspeed governor comprising:

[0009] a sheave rotatably mounted relative to the frame;

[0010] a cam mounted on one side of the groove wheel so as to rotate together with the groove wheel;

[0011] a pendulum member mounted on the frame for rotation about a pivot point, the pendulum member being provided with a trip pawl at a second end thereof;

[0012] a cam follower wheel mounted on the pendulum member at a first end thereof so as to follow a profile of the cam as the sheave rotates, the profile of the cam being such that the cam follower momentarily loses contact with the cam at intervals for rotational speeds of the sheave greater than a first rotational speed;

[0013] a plurality of engagement portions arranged on one side of the sheave so as to rotate with the sheave, the engagement portions and the pendulum member being arranged such that upon reaching a second rotational speed of the sheave that is greater than the first rotational speed, the release pawl engages one of the engagement portions;

[0014] A main resistance element is mounted between the frame and the pendulum member.

[0015] Originally, the overspeed governor comprises at least one additional resistance element, which is configured to act on the pendulum member starting from a third rotational speed of the sheave. The third rotational speed has a value between the first rotational speed and the second rotational speed.

[0016] According to one aspect of the invention, the overspeed governor comprises a lever mounted at a pivot point of the pendulum member. The resistance element is arranged to act on the lever.

[0017] According to one aspect of the invention, an overspeed governor includes a drive pin extending from a pendulum member.

[0018] Preferably, the drive pin and the lever are arranged relative to one another such that, when a third rotational speed of the sheave is reached, the drive pin is in contact with the lever.

[0019] Preferably, the overspeed governor includes an adjustable mechanical stop operatively acting on the lever to set a desired distance of the lever from the drive pin.

[0020] According to one embodiment, the additional resistance element is a weight.

[0021] According to an alternative embodiment, the additional resistance element is a tension spring.

[0022] According to an alternative embodiment, the additional resistance element is a torsion spring.

[0023] According to an alternative embodiment, the additional resistance element is a compression spring.

[0024] According to a preferred embodiment, the main resistance element is a tension spring.

[0025] According to one aspect of the invention, the overspeed governor comprises a switch arranged such that when the sheave reaches a third rotational speed, the pendulum member activates the switch. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] Other features and advantages of the present invention will become more apparent from the non-limiting description of a preferred but non-exclusive embodiment of an overspeed governor for an elevator and an elevator comprising such an overspeed governor, as shown in the accompanying drawings, in which:

[0027] - Figures 1 to 3 An overspeed governor for an elevator according to the present invention is shown in a rear view, a stereoscopic view and a front view respectively;

[0028] - Figures 4 to 7 The following view shows Figures 1 to 3 Different embodiments of additional resistance elements for overspeed governors. DETAILED DESCRIPTION

[0029] With reference to the accompanying drawings, reference numeral 1 indicates an overspeed governor for an elevator. In particular, the overspeed governor is of a latching type, as presented below. In the following, the overspeed governor 1 will be referred to simply as a "governor".

[0030] The speed regulator 1 comprises a sheave 2 which is rotatably mounted relative to a frame 25 . In particular, the sheave 2 rotates relative to an axis of rotation X. Preferably, the axis of rotation X is defined by a sheave bearing 24 .

[0031] The speed regulator 1 includes a cam 4, which is mounted on one side of the sheave 2 so as to rotate together with the sheave 2. In particular, the cam 4 rotates around the rotation axis X together with the sheave 2.

[0032] The speed regulator 1 comprises a pendulum member 5 mounted on a frame 25 so as to rotate about a pivot point 6. Preferably, the pendulum member 5 has a first end and a second end. Preferably, the first end and the second end are on opposite sides of the pendulum member 5 relative to the pivot point 6. Thus, during rotation about the pivot point, when the first end is upward, the second end is downward, and vice versa.

[0033] The speed regulator 1 comprises a cam follower wheel 3 mounted on a pendulum member 5 at a first end of the pendulum member 5. The cam follower wheel 3 is arranged to follow the profile of the cam 4 when the sheave 2 rotates.

[0034] The speed regulator 1 comprises a trip pawl 8 which is provided on the pendulum member 5 at the second end of the pendulum member 5 .

[0035] The speed regulator 1 comprises a plurality of engagement portions 9 arranged so as to rotate together with the sheave 2. Preferably, the engagement portions 9 are latches. Alternatively, the engagement portions 9 are notches.

[0036] Preferably, the engagement portions 9 are arranged on a support plate 10 which is mounted on one side of the sheave 2 so as to rotate together with the sheave 2. Preferably, the engagement portions 9 are distributed around the rotation axis X in a circumferential direction.

[0037] The profile of the cam 4 is such that for a rotational speed of the groove wheel 2 greater than a first rotational speed, the cam follower wheel 3 temporarily loses contact with the cam 4 at intervals. In other words, the cam follower wheel 3 jumps relative to the cam 4 at intervals.

[0038] Typically, the cam 4 is in the shape of a polygon with rounded corners. In particular, the minimum configuration is a square with rounded corners. The preferred embodiment shown in the figure is a pentagon with rounded corners. A hexagon with rounded corners would also be suitable.

[0039] Suitably, the number of engagement portions 9 needs to correspond to the number of fillets of the cam.

[0040] The engagement portions 9 and the pendulum member 5 are arranged so that upon reaching a second rotational speed of the sheave 2, the trip pawl 8 engages with one of the engagement portions 9. The second rotational speed is greater than the first rotational speed. The second rotational speed is referred to as the tripping speed.

[0041] Preferably, the engaging portion 9 is a notch.

[0042] The speed governor 1 comprises a main resistance element 23 mounted between the frame 25 and the pendulum member 5 , preferably corresponding to a first end thereof.

[0043] The movement of the cam follower wheel 3 along the cam 4 generates a centrifugal force on the pendulum member 5. The resistance provided on the pendulum member 5 against the centrifugal force is key to determining when the cam follower wheel 3 begins to lose contact with the cam 4 (first rotational speed) and when the trip pawl 8 engages one of the notches 9 (second rotational speed).

[0044] The main resistance element 23 always acts on the pendulum member 5 to resist the centrifugal force. Therefore, the main resistance element 23 always provides the same resistance.

[0045] Originally, the speed regulator 1 comprises at least one additional resistance element 12 configured to act on the pendulum member 5 starting from a third rotational speed of the sheave 2. The third rotational speed has a value between the first rotational speed and the second rotational speed.

[0046] In addition to the main resistance element 23, an additional resistance element 12 also acts on the pendulum member 5. This allows the spring rate to be adjusted between the third speed and the second speed, thereby producing a non-linear spring (ie resistance) curve.

[0047] Of course, resistance element 12 only comes into play when the third rotational speed has been reached, before which only main resistance element 23 is active.

[0048] The following is a brief description of the functioning of the overspeed governor. As the speed of the sheave 2 increases, the pendulum member 5 reaches a point at which the cam follower 3 no longer fully follows the cam 4 due to the inertia of the pendulum member 5 (the first rotational speed described above). This point (i.e., the point at which the cam follower 3 can no longer follow the cam 4) is primarily determined by the primary resistance element 23.

[0049] When the rotation speed of the sheave 2 is further increased, the movement of the pendulum member 5 is also increased accordingly to a level at which the cam follower wheel 3 is disengaged from the cam profile to a certain distance from the cam profile. In this case, one of the notches 9 will catch the trip pawl 8 of the pendulum member 5. Then, the rotation of the sheave 2 is stopped, causing the generation of traction between the sheave 2 and the speed governor rope. By utilizing this traction, the upward or downward safety device attached to the rope of the speed governor is actuated.

[0050] Starting from the third rotational speed, the resistance provided against the centrifugal force of the pendulum member 5 can be adjusted due to the intervention of the resistance element 12 .

[0051] According to a preferred embodiment, the speed governor 1 comprises a lever 13 mounted on the pivot point 6 of the pendulum member 5. The pendulum member 5 is provided with a drive pin 14 extending therefrom.

[0052] Preferably, the resistance element 12 is arranged to act on the lever 13. Preferably, the drive pin 14 is located on the side of the pendulum member 5 opposite the cam follower wheel 3 with respect to the pivot point 6. In particular, the drive pin 14 is integral with the pendulum member 5 so as to transmit the received force to the pendulum member 5.

[0053] The lever 13 and the drive pin 14 are arranged relative to each other so that the drive pin 14 comes into contact with the lever 13 when the third rotational speed is reached. This causes the resistance element 12 to act on the pendulum member 5.

[0054] Preferably, the lever 13 is held at a set distance from the drive pin 14 by an adjustable mechanical stop 15. The set distance is considered in the static state of the overspeed governor. In this way, the moment when the resistance element 12 should act can be adjusted with the stop 15.

[0055] Preferably, the mechanical stopper 15 is supported by a bracket 16 mounted on the frame 25. Preferably, the mechanical stopper 15 is fastened to the bracket 16 by a nut 17.

[0056] According to a first embodiment, the resistance element 12 is a weight. The required force can be adjusted by adding or removing weight.

[0057] According to a second embodiment, the resistance element 12 is a tension spring. The required force can be adjusted via the eccentric cam 18. Preferably, the eccentric cam 18 is held in position by a nut 18a.

[0058] In particular, the eccentric cam 18 can be used to change the pretension of the extension spring. The pretension is defined by the position of the adjustable stop 15 and the position of the eccentric cam 18. For adjustment, the spring pretension as well as the speed can be changed (via the eccentric cam 18) when the extension spring 12 adds an additional force to the main resistance element 23 (via the adjustable stop 15). As soon as the trip pawl 8 moves further than the expected distance for the third speed, the additional lever 13 is lifted from the adjustable stop 15 via the drive pin 14 and the adjusted pretension of the extension spring 12 is immediately added to the force of the main resistance element 23.

[0059] According to a third embodiment, the resistance element 12 is a torsion spring. The required force can be adjusted with a first adjustment screw 19, which acts on the torsion spring itself (preferably on one end thereof). The first adjustment screw 19 is fastened with a nut 19a. The first adjustment screw 19 is preferably at least partially housed in a housing 19b.

[0060] According to a fourth embodiment, the resistance element 12 is a compression spring. The required force can be adjusted by a second adjusting screw 20 acting on the bracket 21, which compresses the compression spring more or less. Preferably, the adjusting screw 20 is fastened to the bracket 21 by a nut 22.

[0061] According to a fifth embodiment (not shown), the resistance elements 12 are magnets with opposite polarities.

[0062] According to one embodiment, the speed regulator 1 comprises more than one resistance element 12. The resistance elements 12 may be of the same type or a combination of different types.

[0063] According to a preferred embodiment, the speed regulator 1 comprises a switch 26 arranged to be activated by the pendulum member 5 when the sheave 2 reaches a third rotational speed. In this case, the third rotational speed is referred to as the touch-down speed.

[0064] Preferably, the pendulum member 5 includes an actuating bolt 27 extending from one end thereof.

[0065] When the contact switch opens, the elevator's safety chain opens, causing the motor to shut down and the motor brake to close. If this does not work and the car or counterweight is still accelerating (e.g. gearbox failure, brake failure or hoist rope breakage), the emergency brake (safety gear) is mechanically triggered, ensuring a mechanical stop of the car or counterweight as a second level of safety.

[0066] According to a preferred embodiment, the main resistance element 23 is a tension spring. The installation operation is the simplest and there is very little risk of wear between the parts, because the main resistance element undergoes a very large number of cycles (for example, the tension spring is extended 5 times per rotation of the sheave), while the additional resistance element is extended / moved only when exceeding the third speed, which only occurs in emergency or test situations.

[0067] However, the same main resistance may be provided by a torsion spring or other types of resistance elements as already mentioned above.

[0068] According to the preferred embodiment shown in the figures, there is more than one additional resistance element 12. The additional resistance elements 12 used can be of the same type (e.g., multiple extension springs or torsion springs or weights or compression springs) or of mixed types (e.g., one extension spring, one torsion spring, one weight and one compression spring). In addition to the choice of configuration, all these additional resistance elements 12 will only act on the pendulum member 2 after the third speed of the sheave 2 is reached.

[0069] From the above description, the characteristics and advantages of the overspeed governor for an elevator according to the present invention and the elevator comprising such an overspeed governor clearly emerge.

[0070] In particular, the presence of at least one additional resistance element, which intervenes only after reaching the third speed, allows the force opposing the centrifugal force to be adjusted. This makes the speed governor highly versatile and safe, since the parameters can be adjusted arbitrarily.

[0071] Furthermore, different embodiments of the resistance element provide a high repeatability of the contact speed / tripping speed ratio.

[0072] Furthermore, the different embodiments of the resistance element described allow for an easy adjustment of the speed regulator.

Claims

1. An overspeed governor (1) for an elevator, the overspeed governor (1) comprising: a sheave (2), the sheave (2) being rotatably mounted relative to the frame (25); A cam (4), the cam (4) being mounted on one side of the groove wheel (2) so as to rotate together with the groove wheel (2); a pendulum member (5) mounted on the frame (25) so as to rotate about a pivot point (6), the pendulum member (5) being provided with a release pawl (8) at its second end; a cam follower (3) mounted on the pendulum member (5) at a first end thereof so as to follow the profile of the cam (4) as the sheave (2) rotates, the profile of the cam (4) being such that the cam follower (3) temporarily loses contact with the cam (4) at intervals for a rotational speed of the sheave (2) greater than a first rotational speed; a plurality of engagement portions (9) arranged on one side of the sheave (2) so as to rotate together with the sheave (2), the engagement portions (9) and the pendulum member (5) being arranged such that when a second rotational speed of the sheave (2) greater than the first rotational speed is reached, the trip pawl (8) engages one of the engagement portions (9); a main resistance element (23), the main resistance element (23) being mounted between the frame (25) and the pendulum member (5), The overspeed governor (1) comprises at least one additional resistance element (12), which is configured to act on the pendulum member (5) starting from a third rotational speed of the sheave (2), the value of the third rotational speed being between the first rotational speed and the second rotational speed.

2. An overspeed governor (1) according to claim 1, comprising a lever (13), which is mounted on the pivot point (6) of the pendulum member (5), and the resistance element (12) is arranged to act on the lever (13); the overspeed governor (1) also includes a drive pin (14) extending from the pendulum member (5), and the drive pin (14) and the lever (13) are arranged with respect to each other so that when the third rotation speed of the groove wheel (2) is reached, the drive pin (14) contacts the lever (13).

3. An overspeed governor (1) according to claim 2, comprising an adjustable mechanical stop (15), which can be operatively acted on the lever (13) to set the desired distance of the lever (13) from the drive pin (14).

4. An overspeed governor (1) according to any one of the preceding claims, wherein: The additional resistance element (12) is a weight.

5. An overspeed governor (1) according to any one of claims 1 to 3, wherein: The additional resistance element (12) is a tension spring.

6. An overspeed governor (1) according to any one of claims 1 to 3, wherein: The additional resistance element (12) is a torsion spring.

7. An overspeed governor (1) according to any one of claims 1 to 3, wherein: The additional resistance element (12) is a compression spring.

8. An overspeed governor (1) according to any one of the preceding claims, wherein: The main resistance element (23) is a tension spring.

9. An overspeed governor (1) according to any one of the preceding claims, comprising a switch (26) arranged such that the pendulum member (5) activates the switch (26) when the sheave (2) reaches the third rotational speed.

10. An elevator comprising an overspeed governor (1) according to any one of the preceding claims.

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