FI88603B - Emergency brake - Google Patents

Description

S 8 6 O 3

EMERGENCY BRAKE - NÖDBROMS

The present invention relates to an elevator emergency brake comprising a frame consisting of two articulated scissor body parts, one end of the frame provided with friction members with friction surfaces running on both sides of a rail in the elevator shaft, such as an elevator guide, and the frame a spring located between or outside the parts, and 10 of which at least one of the friction members is a wedge or the like controllable between the frame and the guide during emergency braking, the emergency brake having an electromagnetically adjustable electromagnet or a similar, reciprocating control device connected to and controlling the electromagnet; a measuring member further connected to the control device.

Known elevator emergency brakes consist of e.g. spring-loaded long scissors or pliers moving 20 attached to the elevator car along a guide in the elevator shaft. In an emergency braking situation, a separate speed limiter following the movements of the elevator car, e.g. by centrifugal force monitoring the elevator car speed, is activated,

In a gripper acting as an emergency brake, the spring force must be adjusted to a maximum load of 30 car bodies so that the desired deceleration is achieved in the braking situation. Generally, the desired deceleration is adjusted to 0.2-1.4 G.

In practice, the deceleration value differs much from the set value of £ 3; in fact, the known deceleration in known devices is only the average deceleration of the braking time. The momentary deceleration of the elevator car is affected at least by the load of the car, its initial speed in the event of braking and the thermal 2 88603 condition. Thus, the deceleration curve of the elevator car is in fact first a gently rising or flat curve below the set average, which towards the end rises to a steep peak, whereby the deceleration can be a multiple of the control value 5 (e.g. 0.6G). With a light load, the deceleration can be as high as 2.0-2.5 G. Such decelerations are very unpleasant and even dangerous.

The high maximum speed of the elevator complicates the situation in many 0 ratios; on the one hand, the spring force of the gripper must be large enough for extreme situations, on the other hand, the coefficient of friction between the braking surfaces decreases as the speed increases, which means that the spring force must be further increased. The higher the spring force of the gripper, the steeper the deceleration curve 5 at least in conditions milder than the design starting points.

DE-A-2003951 discloses a brake for braking a rotating shaft, which has an electrically adjustable electromagnet, a feedback control device connected thereto and controlling it, and a deceleration measuring element of an escalator or the like coupled to the control device.

The object of the present invention is to eliminate the disadvantages of the prior art 5 and to provide a brake by means of which the emergency braking of an elevator can be performed in a controlled manner. The emergency brake according to the invention is thus characterized in that the deceleration measuring element is an acceleration sensor and that the electromagnet is spring-like on the other side of the articulation point between or outside the body parts so as to reduce either the tensile force in the friction surfaces or reduce the tensile force on the friction surfaces. thrust effect increasing normal force.

The invention provides a substantially constant deceleration of the elevator car during emergency braking, since the frictional force on the brake surfaces is constant. Emergency braking controlled in this way also has several other advantages, as will be shown below. As an additional advantage, it can be stated that the gripper arrangement presented now functions as a completely normal gripper in the event of, for example, a power failure. Thus, a power failure does not cause 5 problems in the operation of the gripper, even if the deceleration measurement and the electric feedback of the gripper do not work. This is a noteworthy factor in terms of elevator occupant safety and elevator regulations.

The invention will now be described in more detail by way of example with reference to the accompanying drawings, in which

Figures 1a and Ib show an elevator emergency brake-Rua according to the invention applied to a scissor-type gripper.

15

Figure 2 shows a section II-11 of Figures 1a and 1b.

Figure 3a shows the deceleration of the elevator car as a function of time using the emergency brakes currently in use,

Figure 3b shows the deceleration of an elevator car as a function of time using an emergency brake according to the invention.

Figure 3c shows the deceleration of an elevator car as a function of time using an emergency brake according to another embodiment of the invention.

The previously known parts of the gripper to be fastened to the car shown in Fig. 1a, which at the same time form in principle a prior art gripper device, are two parts 1 and 2 of a scissor body articulated to each other at 3. A second scissor body 1,2 with friction members 4,5 the head is open and normally runs freely on both sides of the elevator shaft guide 6. At the opposite end of the scissor body 35 1,2 there is a spring 7 outside the body parts. To adjust the spring tension, a shaft 8 runs inside it, to which a spring-length adjusting plate-nut assembly 4 »8603 9 is connected. In the braking situation, the wedge 4 rises. , 17 are pressed against the surfaces of the guide 6 while trying to open the open end of the scissor body 1,2, whereby the spring 7 is compressed to some size. In this case, the compression of the spring size-5 causes a normal force acting perpendicular to the friction surfaces 16,17. Figure Ib shows a solution in which the spring 7 is placed between the body parts.

The friction members 4,5 are formed according to Fig. 2 by way of example of at least one wedge 4 sliding relative to the scissor body 2, and in this example case of a brake pad-like abutment surface 5 formed in the second part 1 of the scissor body. of two wedges sliding in opposite directions, as disclosed, for example, in Finnish patent application no. 861,892.

Implemented by the prior art, the lifting member 10 following the elevator car 30, which normally moves with the elevator car, is stopped, whereby it pushes the wedge 4 upwards relative to the downwardly moving elevator car. This is because the gripping device still follows the elevator car on its way down (arrow). The wedge 4 then has a wedge angle α-15 of zero motion and force against the guide 6, whereby due to the structure of the gripper the wedge and the abutment surface 5 quickly press against the surfaces of the guide 6, whereby the elevator car stops by the frictional force maintained by the gripper spring 7. For the reasons explained above, the deceleration curve of the elevator car with respect to the set value of 0.6G is then as shown in Fig. 3a. The notation -a in Fig. 3a means negative acceleration, i.e. deceleration. 1

The gripper according to the invention comprises an electromagnet 11, like a spring 7, outside or between the frame parts (Fig. 1a), (Fig. Ib), a feedback controller 5? 8603 controlling it and an accelerometer 13 is measured by means of an acceleration sensor 13, on the basis of which the controller, i.e. the servo 12, is controlled so that the frictional force between the surfaces 16,17 of the gripper friction members 4,5 and the surfaces of the elevator shaft guide 6 keeps the car deceleration 10 substantially constant. The electromagnet further comprises a shaft 14 to which the abutment plate 15 is adjustably attached. The traction effect provided by the electromagnet is applied between the plate 15 and the electromagnet 11, whereby the traction effect reduces the normal force on the friction surfaces 16,17 according to the control signals given to the electromagnet 11 by the servo control 12 and thus also the frictional force. In this way, a uniform deceleration of the elevator car according to the deceleration curve of Fig. 3b and complying with the set value 20 0.6G is obtained.

The arrangement according to the invention results in e.g. the fact that the force of the spring 7 can be dimensioned to be greater than the calculated average deceleration of the elevator car.75 would otherwise be possible, because the feedback servo control quickly corrects the deceleration to its correct value. This results in the curve shape in Figure 3b at the beginning of braking. The safety also increases at the critical time of the emergency braking, i.e. at the moment of friction formation, when possible wear and failures of the braking surfaces can at least in principle cause the emergency brake to fail due to insufficient friction generation.

It will be apparent to those skilled in the art that the various embodiments of the invention are not limited to the above example, but may vary within the scope of the claims below. Thus, the pulling electromagnetic arrangement 688603 shown can be replaced by a double-acting electromagnetic arrangement, whereby the plate 15 is replaced by an electromagnet. The advantage in this case is that, thanks to the pushing force, the normal force in the friction surfaces can also be increased in addition to the reduction 5. In this case, the spring force does not need to be adjusted higher than the average deceleration would require. An additional advantage in this case is the soft start of the deceleration according to Fig. 3c.

Claims (1)

7 '<8 603 CLAIMS Emergency brake for an elevator, comprising a frame consisting of two articulated scissor body parts (1,2), the other end (4,5) of the frame 5 having friction members (4,5) with friction surfaces running on both sides of the elevator shaft a rail (such as an elevator guide) having a spring (7) interposed between or outside the frame portions on one side of the frame articulation point, and at least one of the friction members is a wedge (4) or the like controllable by the frame (1) in emergency braking. 2) and between the guide (6), where the emergency brake has an electromagnetically adjustable electromagnet (11) or similar, a separate feedback device (12) connected to and controlling the electromagnet and an elevator deceleration measuring device further connected to the control device (12) , characterized in that the deceleration measuring element is an acceleration sensor (13) and that the electromagnet is arranged like a spring on the other side of the articulation point between or outside the body parts 20 so that, depending on its structure, either a tensile effect reducing the normal force on the friction surfaces or a pushing effect increasing the normal force on the friction surfaces is produced. 8 ^ 8603 The device is designed to be lifted, preferably to a maximum of 5 times (1,2), and then to 5 or more (4.5) to be used with the friction system (4.5), vilka löper pä ömse sidor om en i hisschaktet belägen skena, säsom en hissgejd, och i vilken stomme pä andra sidan leden mellan eller ytterom stomdelarna anbringats en f jäder (7), och av vilka friktionsorgan ätminstone det ena 10 är en kil (4) or if the current is different from the styrene and in the stem (1,2) and the ground (6), if the slurry is used with electromagnets (11) or if it is different from the styrofoam (12) the retardation and the body of the device 15 are retarded by means of a retardation (12), the retardation means of the retardation-retaining organ and the accelerator (13), and the electromagnets and the electrodes of the ground and the retraction In the case of an external stack, there are at least 20 decisions of the construction of the enclosure of the minimum normal and friction system.