Control system of the position, speed limit and uncontrolled movements of the cabin or counterweight of an elevator

Abstract

 Control system of the position, speed limit and uncontrolled cabin or counterweight movement of an elevator, composed of an electronic equipment installed in the elevator's (11) cabin, including an accelerometer (13), which signal is evaluated in real time by a control unit (15), which calculates precisely the magnitude of the positive and negative accelerations of the elevator's vertical movement axis in both directions, and, thus, the position reached from the reference positions supplied by pre-final sensors (5); so that a micro controller (16) activates an output signal when the maximum velocity of the elevator cabin is exceeded, working on the parachute's (10) release so that the cabin (1) is immobilised.

Description

OBJECT OF THE INVENTION

[0001] The invention is included within the technical field of elevator apparatuses, in particular of elevators intended for transporting people. The elevators for passengers are personal transport means in vertical or inclined direction, running on a rigid support and having a closed carrier. As a result of the various safety components which have to be installed mandatorily therein, passenger elevators are found within the most reliable and secure transport means. Specifically, the present invention tries to provide a solution for three requirements all of which are related to the safety of the elevators; namely:

a) Fulfilling and acting as the existing speed limiter in all of the elevators.

b) Operating as the corrector for unintended cabin movement, and

c) Positioner of the cabin or device that determines and updates the position of the cabin at every moment within the elevator installation.

[0002] The system is composed of an electronic circuit which integrates all the necessary components for its operation in an equipment outside of the elevator, and which, connected thereto, acts on the parachute, or on the starter relay, the gear change, and the stoppage of going up and going down, installed in any elevator, when one of these incidents is detected and determined by means of an accelerometer together with a series of cabin position or pace detectors.

BACKGROUND

[0003] Nowadays, every single one of the requirements, to which the present invention provides a solution, has at least one specific solution based on conventional techniques of different manufacturers; but not a single system or device is known that provides by itself a solution to all these requirements.

[0004] The speed limiters are based on the principle of a corrugated pulley for the cable that rotates around at a speed that is proportional to the speed of the cabin, provided with a centrifugal mechanism for extending a spring, so that upon reaching the release speed threshold, the pulley gets jammed and therewith the cable for moving it. The jamming of the cable causes the release of the wedges of the parachute which stops the cabin. The documents US5052523, US4556155 and US5065845 of OTIS describe devices having these characteristics.

[0005] Also known are devices to control undesired cabin movement. Recent regulations related to safety require that the elevator installations must be protected also against the accidental movement of the cabin of the elevator when the doors of the cabin are opening. These regulations oblige to install a protection against the unintended movement of the cabin (UCMP) in new elevators and establish the general performance requirements for detecting the undesired cabin movement (UCM) and reaction devices, without giving specific design rules, so that currently various structural solutions exist in the elevator's market.

[0006] A UCMP system comprises functionally three interrelated systems: detection, evaluation and reaction. The UCMP detection recognises the occurrence of movement when the elevator has stopped having the doors of the cabin open. The UCMP detection is realised mainly by means of mechanical or electric sensors. The mechanical sensors consist of bars, hinges, springs and so forth, and are driven by the relative movement between the sensor and, for example, the mobile pieces. The electric detection consists mainly of the tracking of the position of the cabin, the position of the doors of the cabin itself or of the stairs to the well, as well as the speed of the cabin. The evaluation of the UCMP "decides" whether the detected movement of the cabin is intentional or not. The evaluation implies the analysis of the detected unintentional movement and the operation of the reaction device. The evaluation may be made mechanically or electrically and in some cases it may not be distinguishable from the detection. In many UCMP versions, the electronic evaluation forms part of the elevator control set or safety circuit. The devices for the reaction of the UCMP stop the elevator within certain limits once the UCM has been evaluated. From the viewpoint of costs and maintenance, the majority of the manufacturer prefers using the detection devices which are already installed in the elevators.

[0007] Contrary to other mandatory safety devices, the UCMP represents more the common acronym of a group of distinct structural technical solutions which have the function of a specific device or apparatus. Since the market of passenger transportation by elevators is dominated by electric traction, and not hydraulic traction, the majority of the UCMP solutions is designed for electric elevator traction. However, many solutions may be used in electric traction as well as in hydraulic elevators, since these two elevator types have similarities in some design aspects. Although the UCMP detection and the reaction devices are generally conventional devices, there is also always some innovation observable, for example, use of RFID and smart control systems. Document US2011/0272216 of MITSUBISHI describes an UCMP device.

[0008] There also exist multiple systems employed for measuring the position of the cabin within the shaft of the elevator:

• Magnetic sensors placed in the cabin, activated by magnets placed in the guide, in every floor position.
• Photoelectric sensors placed in the cabin, activated by reflective screens placed in the guide, in every floor position.
• Perforated tape parallel to the guides, with codification of the relative position to the floor level, read out by sensors in the cabin.
• Absolute rotating impulse encoder of multiple revolutions, fixed in the cabin, with a real spring for the drum position recovery, with supporting cable at the highest part of the shaft or pit.
• Position detector based on the measurement of the vibration of a steel wire placed from the top of the shaft to the pit, sensing by a detector with annular path (Schmersal).
• Incremental impulse encoder placed in the traction engine pulley, integrating the distance covered by the support cable.
• RFID devices encoded with the information of each floor, placed on the level thereof and read out by means of another RFID device supported on the cabin.
• Telemetry laser
• Meter for ultrasound distances

DESCRIPTION OF THE INVENTION

[0009] Each one of the described systems is suitable for supplying the necessary information to manage the starter relays, the speed gears and the stoppage of going up and going down, but no one is based on the technique used as primary instrumentation in aviation, the "dead reckoning" or position evaluation by continuous integration of the accelerations; whereas the system of the invention is based on the determination of speed and position of the cabin of the elevator by evaluating mathematically the accelerations measured in accelerometers fixed at the chassis of the cabin.

[0010] As has already been indicated, the system of the invention allows controlling the positioning of the elevator's cabin, it works also as a speed limiter and detects uncontrolled movements of the cabin or the counterweight of an elevator. The system acts on the parachute when: a) a predetermined release speed has been reached; b) an unintentional movement of the cabin is detected; by determining the position thereof from a reference position, with the purpose of controlling the speed of the operation to perform the stoppage at the level of the desired floor.

[0011] This system is constituted by an electronic equipment installed in the cabin, and comprises the following circuits or functional blocks:

a) an accelerometer that constitutes the fundamental base of the system's operating principle, which emits a signal that is evaluated in real time by a microprocessor or a logic programmable FPGA device, which calculates precisely the magnitude of the positive and negative accelerations of the elevator's vertical offset axis in both directions;

b) a control unit constituted by microprocessor or a logic programmable FPGA device which evaluates in real time the speed and, thus, the position reached from the release of the reference positions provided by pre-final sensors and the terminal stop safety sensors, installed on the sides of the movement guides of the elevator's cabin;

c) a micro controller working as interface with the elevator's control, be it by a field bus or by discrete signals, both coming from amplified logic outputs, that receives the signal of said control unit. Said micro controller receives signals indicating the range in upwards or downwards direction of the stoppage position of the corresponding floors, and registers them during the start-up process in his memory, being internal or associated thereto; as well as the speed change positions of the operating, determined in a common way for all stops from the elevator's dynamic data;

d) a power amplifier that activates the output signals working on the parachute release for immobilising the cabin if the maximum speed of the elevator's cabin is exceeded; and

e) a continuous power source that supplies the energy for maintenance of the control, even in absence of external electric power.

[0012] The industrial design of this system allows its redundancy and self-testing performance to be adapted to the safety regulations and is independent from the type, model or brand of the parachute (Safety Gear) used, as well as from the redundancy and safety elements required for meeting the regulations of every country. The system can work directly with parachutes having electronic release or with electric releases in parachutes having a mechanical release.

[0013] The system is independent from the type of logic circuit used for the mathematic evaluation of the position (microprocessor, FPGA and so forth), as well as the program and/or operative system employed.

[0014] The system can be adapted to any type of elevator, independently whether its operation is electronic or from the mechanic operation thereof.

[0015] The system is independent from its way of assembly or distribution of the electronic functions. It is based on the measurement of the positive and negative accelerations of the cabin and its electronic processing may be local or remote like also the format of the acquired data.

[0016] The target system of the patent is independent from the purpose for which it may be used within the described ones, being usable for every single one of them, two of them or all at once.

[0017] The system is independent from the accelerometer's type used (be it with digital or analogue output) as well as the number of available axes for the use in other physical measurements, through the provided information by the accelerometers. Likewise, it is independent of the accelerometer's brand or model. The system is independent from the means utilised for the "backup" energy, being it by electric (batteries, ultra capacitors and other), pneumatic, hydraulic or mechanic accumulation.

[0018] The system is also independent from the means used for the transfer of the commands to the electronic braking system, or speed and position control system of the elevator, being it by data bus, conventional wiring, optical fibre, WiFi, or any other technical means suitable to transfer a signal.

[0019] The reference position sensor(s) is (are) indicated for purpose of information, since the system may use other reference position means (magnetic, inductive, capacitive, photoelectric, ultrasound, laser, impulse encoder sensors, and so forth) and are totally supplementary to the target system of this patent.

[0020] The system of this invention may be used independently for the speed control of the cabin or the counterweight, both in traction as well as hydraulic operating elevators.

DESCRIPTION OF THE FIGURES

[0021] To supplement the description which is performed and for the purpose of providing the understanding of the features of the invention, the present descriptive specification is accompanied by a set of drawings wherein the following is represented by means of illustration and without limitation:

[0022] Figure 1 shows a schematic elevated view of an elevator.

[0023] Figure 2 represents a functional block scheme of the target system of the present invention.

PREFERRED EMBODIMENT OF THE INVENTION

[0024] In any elevator, the cabin (1) with its skates (2) slides through the guides (3) hanging by the cables (4) or optionally by a hydraulic system. The distance limits are determined by the pre-final position sensors (5) and the endpoint safety sensors (6). The safety brake (7) or parachute (10) is activated through the release (8) of the steering device (9) when the speed limit for the elevator has been reached.

[0025] The aim of the patent is an electronic device installed in the cabin of the elevator (1), which is integrated in an electronic circuit (21) containing an accelerometer (13) which signals are evaluated in real time by a microprocessor or FPGA device (15).

[0026] The accelerometer (13) supplies precise information of the magnitude of the positive or negative accelerations of the vertical movement axis of the elevator in both directions. The programmable logic device (15) evaluates the speed in real time and, thus, determines the position reached from the release of the reference positions supplied by the pre-final sensors (5).

[0027] For long distance elevators, a position refreshing sensor (12) is foreseen with which the real position is imposed over the theoretic estimated one every time the cabin passes in front thereof.

[0028] The continuous power source (14) supplies the energy for maintaining the control even in absence of external electric power. The microcontroller (16) works as an interface with the control of the elevator through a field bus (versatile electric connection) (17) or discrete signals (18) coming from amplified logic outputs (19). These signals indicate the range in upwards or downwards direction of the stop position of the corresponding floors which have been registered during the start-up process in the memory of the microcontroller (16). They also indicate the speed change positions of the operation, determined in a common way for all stops from the elevator's dynamic data.

[0029] If the maximum speed of the elevator's cabin is exceeded, the device (15) activates the output (20) so that the release of the parachute (10) immobilises the cabin (1).

[0030] Once that the nature of the invention as well as one preferred example embodiment has been sufficiently described, it is to be noted for the convenient purposes that the materials, shapes, sizes and arrangements of the described elements may be modified provided that this does not represent an alteration of the essential features of the invention which is claimed below:

Claims

1. Control system of the position, speed limit and uncontrolled cabin or counterweight movement of an elevator; which cabin (1) presents a distance which limits are determined by the pre-final position sensors (5) and the endpoint safety sensors, and having a safety brake or parachute (7) which is activated through the release of the steering device (9) when a predetermined speed limit for the elevator is reached,
characterised in that it is composed of an electronic equipment, installed in the elevator's (11) cabin, the electronic equipment comprising:

a) an accelerometer (13), which signal is evaluated in real time by a microprocessor or a logic programmable FPGA device (15); which calculates precisely the magnitude of the positive and negative accelerations of the elevator's vertical movement axis in both directions;

b) a control unit constituted by microprocessor or a logic programmable FPGA device (15) which evaluates in real time the speed and, thus, the position reached from the release of the reference positions provided by the pre-final sensors (5);

c) a micro controller (16) that works as interface with the elevator's control, through a field bus (17) or discrete signals (19) coming from amplified logic outputs; receiving signals indicating the range, of going up or going down, of the stoppage position of the corresponding floors, which have been registered in the memory of the micro controller (16) during the start-up process; as well as the speed change positions of the operation, determined in a common way for all stops from the elevator's dynamic data;

d) a power amplifier that activates the output (20) which works on the parachute's (10) release so that the cabin (1) is immobilised if the maximum speed of the elevator's cabin is exceeded; and

e) a continuous power source (14) that supplies the energy for maintenance of the control, even in absence of external electric power.

2. System according to claim 1, characterised in that the control unit (16) receives the signal of the pre-final sensors (5) to determine the position of the cabin from the reference position they establish, together with the measurement of the positive and negative accelerations of the cabin; as well as position refreshing sensors (12) with which it is allowed to establish the real position which is imposed over the theoretic estimated one, every time that the cabin passes in front thereof.

3. System according to claim 1, characterised in that this equipment is installed in redundancy with the safety installation that exists in the elevator, working on the parachute, having that one an electronic or mechanic release, when the determined speed has been reached, or when an unintentional movement in the cabin is detected.

Drawing