EP0081212A1 - Safety device for an elevator or hoist - Google Patents

Abstract

Safety device for an elevator (1) limiting its descent, comprising an element forming a stop means (22) fixed to the guide (8) of the elevator (1), a movable element (24) mounted on the upper frame (3) of the elevator, and means (29) for driving the said movable element (24) between an active position in which it extends above the said element forming the stop means (22), and a retracted position in which it does not encounter the said element forming a stop means (22) during the movement of the elevator, it being possible for this device to be combined with a parachute (10). Application of the said safety device to elevators with drive members of the hydraulic type. <IMAGE>

Description

The present invention relates to a safety device for lifting devices such as elevators or hoists.

The main safety devices currently used in lifting devices such as elevators or hoists are formed by parachutes which are mechanical organs intended to stop and keep the elevators or hoist stationary on their guide in case overspeeding when lowering or breaking the suspension members.

Different types of parachutes are currently used, including instantaneous parachutes, instantaneous parachutes with cushioned effect and cushioned parachutes.

As safety devices, there are also known isivelling means which allow upgrading of elevators or hoists during loading or unloading operations by actuation of the drive members.

A safety problem arises, however, in lifting devices, the motor parts of which ensure the movement and stopping of these devices are of the hydraulic type or of the hydraulic and cable type, the hydraulic means generally being formed by jacks. In fact, during a power outage, the leveling means cannot operate and, due to residual leaks, the lifting devices involving hydraulic means can descend to a level located far from the level where they were before the power went out. This untimely descent represents a danger for people, especially if an access door remains open and considerably disrupts the driving organs and safety systems.

The present invention aims to remedy these drawbacks and proposes a safety device particularly suitable for lifting devices of the hydraulic type while also being applicable to lifting devices of the cable type or any other type.

The safety device according to the present invention makes it possible to immobilize a mobile lift or hoist at a determined level substantially vertically along at least one guide thanks to motor members which are capable of ensuring the movement ₂ t of stopping said elevator at a level corresponding to a landing threshold, said determined level being located at or below said level corresponding to the landing threshold.

The safety device according to the present invention comprises a fixed element forming a vertical stop independent of the elevator, a mobile element mounted on the frame or stirrup of the elevator and capable of occupying an active position in which it extends at least partly above said element forming a stop to come to bear therein in order to maintain said elevator at said determined level and a retracted position in which it does not meet said element forming a stop when the elevator is driven by said motor members, and means for driving said mobile element to move the latter between its active position and its withdrawal position.

Although it may be completely different, said movable member preferably comprises a substantially horizontal rod movable through guide support means fixed to said stirrup substantially perpendicular to the movement of said elevator.

According to the present invention, said rod is prefer- _ence, at least in part movable -to up in said guide support means so that, when it bears on said abutment member, it acts on a control contact of said drive members if the elevator descends so that these drive members raise said lift to said level of threshold level. In this way said stop member, said rod and said control contact advantageously constitute isivelling means.

According to the present invention, said rod and said stop member may in themselves constitute means for maintaining the level of the elevator. However, in a particularly advantageous alternative embodiment, said rod can, as previously, be provided at least partially movable upward in said guide support means so that, when it is in abutment on said stop element, it acts on the element blocking a parachute associated with said elevator guide if the latter descends, with a view to mechanical blocking of the elevator by said parachute.

According to the present invention, the safety device can comprise a safety contact on which said rod acts when said parachute is engaged. This safety contact can advantageously be mounted in series with the control elements of the leveling means. In fact, as soon as the electric current is restored, the drive components will go up the elevator to the threshold level.

When said parachute blocking element is formed by a wedge or a roller carried by a lever which is articulated on the stirrup of the elevator, it can be provided that said rod stops below this lever and can act on it in order to activate the parachute.

The security device according to the present invention preferably comprises a position detector of said mobile element, this position detector authorizing the actuation of said motor members only when said mobile element is in its withdrawn position.

According to the present invention, said drive means may comprise a means for returning said movable element which moves up to and maintains in its active position this movable element when said motor members are not actuated, this return means can advantageously be formed by a spring.

Said means for driving said movable element may also comprise an electromagnet which moves up to and maintains in its withdrawn position said movable element when said motor means are actuated.

• - la figure 1 montre une vue frontale d'un ascenseur représenté partiellement et muni du dispositif de sécurité selon la présente invention ;
• - la figure 2 représente une vue latérale partielle de l'ascenseur représenté sur la figure 1
• - et les figures 3a, 3b et 3c montrent schématiquement le fonctionnement du dispositif de sécurité représenté sur les figures 1 et 2.

The present invention will be better understood from the study of a safety device for a particular elevator, described by way of nonlimiting example and illustrated by the drawing in which:

• - Figure 1 shows a front view of an elevator partially shown and provided with the safety device according to the present invention;
• - Figure 2 shows a partial side view of the elevator shown in Figure 1
• - and Figures 3a, 3b and 3c schematically show the operation of the safety device shown in Figures 1 and 2.

The figures show an elevator generally identified by the reference 1 which has been shown very schematically so as not to overload the drawing and to better highlight the safety device generally identified by the reference 2. In addition, and for the same purposes, the drive members for moving and stopping the elevator 1 have not been shown.

The elevator 1 comprises a stirrup generally identified by the reference 3 which has, depending on the use, crosspieces and uprights which form a chassis capable of carrying a cabin 4 having a receiving floor 5.

Usually, the stirrup 3 comprises in the example shown, two lateral sections 6 and 7 which are mounted vertically and which have a U-shaped section open in opposite directions. These sections 6 and 7 are intended for mounting guide slides of the stirrup 3 along vertical guides or rails 8 and 9 which are of T-shaped section arranged in opposite directions and which are generally fixed to the surrounding construction. the elevator shaft, these slides not being visible in the figures. Profiles 6 and 7 are also used for mounting parachutes 10 and 11.

As can be seen in Figure 2, the parachute 10, in the example shown, comprises a parachute block 12 which is disposed astride the profile 8 and mounted between the elders of the profile 6 to be fixed to the core of the latter by means of screws or bolts 13. The parachute block 10 comprises a U-shaped groove 14 which is crossed by the core 8a of the guide 8, this vertical groove 14 having a vertical face 15 parallel to and distance from one side of the core 8a and a face 16 situated on the other side of the core 8a and inclined so that the faces 15 and 16 are in the form of a cone open downwards.

The parachute 10 also comprises a roller 17 which is disposed between the inclined face 16 and the face of the core 8a of the corresponding guide 8 so as to be able to roll on these faces. The roller 17 is mounted at one end of a horizontal lever 18 which extends substantially perpendicular to the guide 8 and which passes in front of the wing 6a of the profile 6 located on the same side of the core 8a of the guide 8 as the inclined face 16 of the parachute block 12. The other end of the lever 18 is hingedly mounted on an axis 19 carried by the stirrup 3.

The parachute 11 is constructed in the same way as the parachute 10 and comprises a parachute block 20 mounted between the wings of the profile 7, a lever 21 and a roller arranged in a groove of the parachute block 11, this roller and this groove n 'not being visible in the figures.

In the example shown, the levers 18 and 21 of the parachutes 10 and 11 are mounted on the same axis 19 so that they are integral in rotation.

We will now describe the safety device 2 which is associated with the parachutes 10 and 11.

· The safety device 2 comprises an element forming a stop 22 which is constituted by a cleat which is fixed for example by welding to the back of the guide 8 and which largely exceeds the side of the lever 18 so as to present an upper face 23 which is substantially horizontal. We will see below where this stop 22 is located.

The safety device 2 also comprises a mobile element which is formed by a rod 24.

The rod 24 extends substantially horizontally. It is therefore substantially perpendicular to the movement of the elevator 1. The rod 24 extends below the lever 18 of the parachute 10 and constitutes a downward stop for this lever normally preventing the roller 17 from being in contact with the inclined face 16 of the parachute block and the core 8a of the guide 8. It further extends substantially perpendicularly to this lever and to the element forming a stop 22.

The rod 24 is also carried by guide supports 25 and 26 which are fixed to the bracket 3 and which are in the form of plates substantially perpendicular to the rod 24. The guide support 26 which is located on the side of the end 24b of the rod 24 opposite its end 24a which extends beyond the lever 18 and on the side of the stop 22, has a circular orifice 27 through which the rod 24 extends, this orifice 27 having a diameter greater than the diameter of the rod 24. The guide support 25 which is between the lever 18 and the support 26 has an orifice 28 through which the rod 24 extends, this orifice 28 having a vertical oblong shape, the part lower part of this orifice 28 being substantially at the same level as the lower part of orifice 27 of the guide support 26. The guide supports 25 and 26 are intended to carry the rod 24 and to guide the latter during its movements substantially perpendicularly to the movement of elevator 1 as it will appear more s far away.

The safety device 2 also comprises means for driving the rod 24 which are formed, in the example shown, by an electromagnet 29, the movable core of which is connected to the rod 24 by means of a rod. 30 and a yoke 31, a return spring being provided in the electromagnet 29. Other means for driving the rod 24 can be provided. One can for example connect the rod 24 to the electromagnet 29 by means of reduction levers. In addition, it is also possible to provide means for adjusting the position and the stroke of the rod 24, these adjustment means being for example of the screw-nut type.

Referring to Figures 3a, 3b and 3c, we will now describe how the rod 24 moves.

When the electromagnet 29 is not energized, the return spring which it comprises maintains the rod 24 in an active position in which its end 24a extends above the stop 22 so that if the 'elevator descends, the end 24a of the rod 24 comes to bear on the upper face 23 of the stop 22. This position is shown in Figure 3b.

When the electromagnet 29 is de-energized, its return spring moves the rod 24 from its withdrawn position to its active position.

With reference to FIGS. 3a, 3b and 3c, the operation of the safety device 2 associated with the parachute 10 will be completely described.

If you want the elevator 1 to reach level A, you press a control button for the elevator's drive components. However, in the present case, the starting of the driving members is not done directly. Indeed, the operation of this control button allows the excitation of the electromagnet 29 which, against its return spring, moves the rod 24 from its active position to its withdrawal position. When the rod 24 reaches its withdrawn position, it acts on a position detector 32 which, for its part, authorizes the starting of the drive members. The safety device 2 is then in the position shown in Figure 3a and the elevator can move freely.

When the floor 5 of the elevator 1 reaches level A, the drive members are stopped and maintain so usual this lift in a fixed position. As soon as the elevator 1 has stopped, the electromagnet 29 is de-energized and its return spring moves the rod 24 from its withdrawn position to its active position so that its end 24a extends above of the stop 22 which is fixed to the guide 8 so as to be disposed just below or at a suitable distance from this end when the rod 24 is in this position. The safety device 2 is then in the position shown in Figure 3b.

If for any reason and in particular because of the loading of the elevator 1 the latter comes to descend, the end 24a of the rod 24 comes to bear on the upper face 23 of the stop 22 and the rod 24 tilts in pivoting in the hole 27 of the guide support 26 and moving upwards in the oblong hole 28 of the guide support 25 (FIG. 3c). After a determined upward movement in the orifice 28 of the guide support 25, the rod 24 meets a position detector 33 placed between the profile 6 and the guide support 25, and which serves as a leveling control means and which starts the motor components so that they go up the elevator 2 so that its floor 5 returns to level A.

If for any reason and in particular due to a power cut the elevator descends, the end 24a of the rod 24 comes to bear on the upper face of the stop 22 and tilts as we have seen previously . When the rod 24 acts on the position detector 33, nothing happens given the power cut. The elevator continuing its descent, the rod 24 continues to tilt while remaining supported by its end 24a on the stop 22 and drives the lever 18 by pivoting it upwards around its axis of articulation 19. After a determined stroke, the roller 17 is blocked between the face 16 of the parachute block 12 and the core 8a of the guide 8. As the levers 18 and 21 are integral, les.parachutes 10 and 11 engage substantially at the same time and the elevator 1 is then blocked on its guides 8 and 9 and its descent is stopped.

When the power is restored, a position detector 34, placed between the guide supports 25 and 26, near the guide support 25, which comes into contact with the rod 24 indicates that the parachutes 10 and 11 are in engagement and controls l 'actuation of the drive members which go up the elevator 1 to level A and, in doing so, the rollers, the parachutes 10 and 11 roll and unlock, the rod 24 returning to its initial horizontal position. To complete the device, a return spring could be provided towards the bottom of the rod 24.

It is obviously preferable for the leveling contact 33 to start the driving members before the parachutes 10 and II engage. Adjustment of detectors 33 and 44 cannot be made accordingly. The detectors 32, 33 and 34 are fixed to the bracket 3.

As described above, the safety device 2 is such that the lever 18 of the parachute 10 is supported on the rod 24. However, it could be provided at a distance to have a guard increasing the possible vertical displacement of the end 24a of the rod 24 so as to more easily adjust the position detectors 33 and 34.

In the embodiment of Figure 1, the end 24a of the rod 24 is bevelled so as to be longer in its lower part and the lower part of the stop 22 also has a bevel substantially parallel to the bevel provided on the end 24a of the rod 24 so that, if for any reason the drive members are started and move the elevator upwards, without the electromagnet 29 being excited, the rod 24 when it reaches the stop 22, slides on the latter so as to avoid it without damaging any parts and the safety device. If the drive members are also started and allow the descent of the elevator 1 without the electromagnet 29 being excited so as to cause the withdrawal of the rod 24, this rod 24 when it will reach the stop 22, actuates the parachutes 10 and II which block the elevator 1 on the guides 8 and 9, the position detector 34 then cutting the electrical circuit of the drive members when it engages.

It is quite obvious that if the elevator 1 is designed to move between several levels, it will preferably be necessary to provide at each level of the landing an element forming a stop corresponding to the stop 22.

As it has just been described, the safety device 2 is particularly well suited for lifts or hoists whose drive members are of the hydraulic type. Indeed, in the event of a power failure or system failure , residual leaks in the hydraulic circuits cause the elevator to descend. The safety device 2 makes it possible to mechanically stop the descent of this elevator.

The present invention is not limited to the example described above. We can indeed provide a safety device having a different structure, it can be associated with parachutes of a different type and it can be used on lifting devices having any motor components. It is also possible to associate a safety device similar to the second parachute. It is also possible to control the blocking of the parachutes 10 and 11 using means reacting to an overspeed of the elevator, the device 2 then being an auxiliary safety device. Other alternative embodiments and combinations are also possible without departing from the scope of the present invention.

Claims (10)

1. Safety device making it possible to immobilize at a given level a lifting device such as an elevator or a freight elevator movable substantially vertically along at least one guide by means of drive members which are capable of ensuring movement and stopping the elevator at a level corresponding to a threshold; said determined level being at or below said level corresponding to the landing threshold, characterized in that it comprises a fixed element (22) forming a vertical stop independent of the elevator (1), a rod (24) substantially horizontal movable mounted substantially perpendicular to the movement of said elevator
and likely to occupy an active position in which it is at least partly above it is at least partly above the elevator forming a stop to come to bear there in order to maintain the elevator at said determined level and a withdrawal position in which it does not meet said stop element when the elevator is driven vertically by said motor members, and drive means (29) of said rod (24) to move the latter between its active position and its withdrawal position, said rod (24) being at least partially movable vertically to move upwards when it is in abutment on said stop member before the said elevator is maintained at said determined level. 2. Safety device according to claim 1, characterized in that it comprises a control contact (33) of said motor members on which acts said rod (24) during its high upward movement, for a reset to said level corresponding to a level threshold of said elevator. 3. Safety device according to claim 1, characterized in that it comprises a parachute (10) associated with said guide (8) and provided with a locking element (17) on which acts said rod (24) during its movement upwards, with a view to blocking the elevator by said parachute. 4. Safety device according to claim 3, characterized in that said rod (24) acts on the locking element (17) of said parachute (10) by means of a lever (18) which carries the blocking element. 5. Safety device according to one of claims 3 and 4, characterized in that it comprises a safety contact (34) on which acts said rod when said parachute is engaged. 6. Safety device according to any one - of the preceding claims, characterized in that it comprises a position deflector (32) of said rod (24). 7. Safety device according to any one of the preceding claims, characterized in that the said drive means comprise a means for returning the said rod which moves up to and maintains in its active position this rod when the said driving members are not activated. 8. Safety device according to claim 6, characterized in that the return means is a spring. 9. Safety device according to any one of the preceding claims, characterized in that the said means for driving the said rod include an electromagnet (29) which moves up to and maintains in the withdrawn position the said rod when said drive members are actuated. 10. Device according to any one of the preceding claims, characterized in that the said rod and / or the said stop member are bevelled so that, when the elevator is mounted, the said rod can slide on the said member. forming a stop to avoid it.

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