Belt-type door opening and closing drive apparatus

Details Belt-type door opening and closing drive apparatus Belt-type door opening and closing drive apparatus

2001-04-06

2003-07-22

Estremsky, Sherry (Department: 3681)

Planetary gear transmission systems or components

Planet pinion is friction gear

C475S182000

Reexamination Certificate

active

06595889

ABSTRACT:

DETAILED DESCRIPTION OF THE INVENTION
1. Field of the Invention
The present invention relates to a belt-type door opening and closing drive apparatus to be used such as for opening and closing the doors of an elevator or an automatic door of stores.
2. Description of the Related Art
For example, following apparatuses are conventionally known as a belt-type door opening and closing drive apparatus for opening and closing the doors of an elevator. An apparatus reduces the output of a motor with (multistage) belts and pulleys and allows the reduced output to drive the door opening and closing belt (a cog belt generally referred to as a timing belt), thereby opening and closing the door. Another apparatus allows the reduced output of a geared motor to drive the door opening and closing belt, thereby opening and closing the door.
The opening and closing drive apparatus for opening and closing the door of an elevator is generally provided with a sensor for detecting a person or some object caught in the door opening. In the event the sensor has detected a person or an object caught in the door opening, the drive apparatus is adapted to open the door of the elevator.
Of the conventional drive apparatuses described above, the one which transmits the output of the motor to the door opening and closing belt (the timing belt) in combination of the belts and pulleys is to reduce the rotational rate of the motor by placing pulleys having different diameters on the input and output sides. To set a higher reduction ratio, this requires generally a multistage configuration of the apparatus (since there is a limit to the reduction in diameter of the input pulley and the increase in diameter of the output pulley). This in turn makes it difficult to provide a compact and an inexpensive apparatus.
On the other hand, the one that employs the geared motor can provide a more compact apparatus than that employing a combination of the multistage belts and pulleys. However, the apparatus presents a problem of providing a high level of noise and causing its mechanical safety function not to work in the event of the sensor failure or the like, as described later.
SUMMARY OF THE INVENTION
The present invention was developed in view of the afore-mentioned problems. It is therefore an object of the present invention to provide a drive apparatus for opening and closing the doors of an elevator, the apparatus being capable of providing a mechanical safety function in the case of an accident.
The present invention provides the following belt-type door opening and closing drive apparatuses to thereby overcome the aforementioned problems. That is, provided is a belt-type door opening and closing drive apparatus for allowing an output of a motor unit to drive a belt to thereby open and close a door. The apparatus is adapted such that between the motor unit and the belt, a planetary roller unit having a sun roller, a planetary roller circumscribing the sun roller, and a ring roller with which the planetary roller is inscribed in is interposed. The planetary roller unit receives the output from the motor unit and an output from the planetary roller unit is transmitted to the belt.
In the present invention, the planetary roller unit is interposed as power transmission means between the motor unit and the belt for opening and closing a door. (Here, the belt is a cog belt which is called a timing belt. However, the present invention is not limited to the cog belt. For convenience, the belt is hereinafter referred to as a timing belt.) The planetary roller unit provides a compact shape and a high reduction ratio, thereby allowing the entire drive apparatus to be made easily compact.
In addition, the planetary roller unit itself transmits power by means of mutual rotations (frictional rotations or traction rotations) of the sun roller, the planetary roller, and the ring roller, thereby providing a quiet operation.
Furthermore, the planetary roller unit makes full use of preventing the vibration from being transmitted between the input and the output side by means of the contact surfaces between the rollers. That is, the planetary roller unit cuts off the vibration produced by the motor unit of the input side and otherwise transmitted to the timing belt, and the vibration generated by the timing belt (the doors of the elevator) to be otherwise transmitted to the motor unit. Accordingly, this makes it possible to prevent the occurrence of the so-called resonance phenomenon in which objects vibrating at natural frequencies different from each other are affected by each other to produce a greater vibration or noise than that produced by each of the objects. Consequently, it is made possible to significantly increase the quietness of the entire drive apparatus.
Furthermore, the planetary roller unit is characterized by its structure that will cause each roller to slide upon application of an excessive load to the output side, thereby allowing no more torque to be transmitted. If the sensor system fails to detect a person or an object caught in the opening between the doors and stop or reverse the rotation of the motor shaft, leading to a situation where the motor unit continues to work with the person or object being caught in the opening, the present invention makes it possible to prevent the excessive torque from being acted upon the person or object being caught in the opening. In other words, the present invention can make full use of the mechanical safety function in the event of an accident. This function is effective particularly when a special emphasis is placed on the response speed of opening and closing the door and therefore a relatively high torque is required of the motor.
Incidentally, the motor unit may include a flat motor having a shortened axial dimension.
Employing such a flat motor for the motor unit makes it possible to reduce the axial dimension(size), thereby allowing the axial dimension of the entire drive apparatus to be further reduced while the properties of the planetary roller unit are being put to use.
Furthermore, the aforementioned planetary roller unit may be of a frame rotational type having a rotational frame member on an outer periphery of the unit itself. The frame member may be coupled to the ring roller so as to rotate integrally therewith, and the frame member itself may be provided with a pulley for driving the belt.
With this configuration, the need for providing a separate pulley in addition to the drive unit is obviated since the frame member itself, which is rotatably integrally coupled to the ring roller, is provided with a pulley for driving the timing belt. Thus, compared with a drive apparatus having a separate pulley connected thereto, this configuration can make the drive system more compact, simplify the structure, reduce the number of components, and contribute to the reduction of cost.
In this case, the ring roller and the frame member may be integrated with each other by a exterior member
100
penetrating the ring roller to the frame member or an extended portion of the frame member.
With this configuration, the exterior member
100
that penetrates the ring roller is supported with the frame member at both axial ends of the ring roller, thereby making it possible to provide improved rigidity for the integration of the ring roller with the frame member.
In addition, irrespective of the number of stages of the planetary roller units, the ring roller and the frame member can be easily integrated with each other.
Furthermore, the drive apparatus can be configured such that multiple stages of the planetary roller units are provided and the output from the motor unit is received by the sun roller of an initial stage planetary roller unit of the multiple stages of planetary roller units. Moreover, the carrier for supporting the planetary roller of a planetary roller unit of a preceding stage including the initial stage is coupled in turn to the sun roller of a following stage planetary roller unit, and then the carrier of a final stage planetary roller unit is fixed. Still

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