Flexible or portable closure – partition – or panel – Roll type – With rotating means
Reexamination Certificate
1999-03-30
2001-05-15
Johnson, Blair M. (Department: 3634)
Flexible or portable closure, partition, or panel
Roll type
With rotating means
C160S189000, C160S133000
Reexamination Certificate
active
06230785
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to an electrically driven closure apparatus for architectures, such as an electrically-driven shutter of a building.
Generally, a closure apparatus having an electric motor to drive a closure member for opening and closing, for example, an entrance of a building has a risk of being jammed with an obstacle when being operated to close. Therefore, the apparatus preferably has an obstacle detector and an automatic stop controller that automatically stops the closure member when the obstacle detector detects the obstacle. Two types of the obstacle detector are known: one is a direct detecting type that detects an obstacle by a detecting sensor such as a seat plate switch provided on the closure member; the other is an indirect detecting type that detects an obstacle indirectly by detecting load variation or torque variation of the electric motor when the closure member is blocked by the obstacle. The indirect type detector has an advantage in that the closure member is not required to have an obstacle sensor and that the obstacle detector can also serve as a limit detector. Conventionally, the indirect type obstacle detector may detect the load variation in accordance with a variation of a rotation speed or an electric current value (or a voltage value). However, a general electric closure apparatus utilizes an electric motor working within a range where the variation of the rotation speed due to the load variation is small, so as to obtain a stable opening and closing speed. Therefore, there is a problem that the variation of the motor speed is small when the closure member is resisted by an obstacle. A problem experienced with the current detecting type is that the electric current can be varied by a disturbance rather than by the load variation. Thus, the above-mentioned detectors have difficulty in detecting an obstacle with high accuracy and good compatibility between detection sensitivity and operation stability.
In order to solve the above-described problem, a mechanism has been proposed which can perform stable opening and closing operation while detecting an obstacle accurately. In this mechanism, an electric motor or a driving device serves as a displaceable member that changes its position in accordance with the load variation. The displaceable member is supported by a load detecting spring (a neutral position keeping spring) that keeps, under a predetermined load, the displaceable member at a neutral position with respect to a fixed member that is fixed to a frame. A displacement sensor detects change in the position of the displaceable member against the load detecting spring.
However, the conventional load detecting spring mentioned above has substantially a U-shape with one end connected to the displaceable member and the other end connected to the fixed member. When the displaceable member changes the position against the spring constant between the both ends, the position change is detected by the displacement sensor. By changing the effective length of the load detecting spring, the spring constant can be changed so as to adjust the accuracy of detection of an obstacle. In this case, the spring constant of the conventional load detecting spring is adjusted by slidably attaching an adjustment member to the parallel portions of the U-shaped spring, so that the curved portion of the spring between the fixed points becomes ineffective. Therefore, the load detecting spring must have effective length large enough to provide the required spring constant and additional length for permitting attaching of the adjustment member. Moreover, the adjustment member must be attached so as not to allow twisting or deflection of the parallel portions of the spring. Thus, the load detecting spring as well as the adjustment member tends to become large.
SUMMARY OF THE INVENTION
An object of the present invention is to provide an electrically-driven closure apparatus for a building that can solve the above-described problems.
To this end, according to the present invention, there is provided an electrically-driven closure apparatus for building, comprising: a closure member for opening and closing an opening in a building structure; a driving device having an electric motor, said closure member being opened and closed by a driving force of the driving device; the motor or the driving device being designed to serve as a displaceable member that changes rotational position relative to a fixed member fixed to the building structure, in accordance with a variation in the load; a load detecting spring disposed between the displaceable member and the fixed member; and a displacement sensor for detecting displacement of the displaceable member against the spring force of the load detecting spring, wherein the load detecting spring is fixed in the state where spring constant is adjustable.
More specifically, since the displacement of the displaceable member is substantially proportional to the motor load or reacting torque, the motor load can be detected directly by the displacement sensor. As a result, higher accuracy can be obtained in the load detection than in the conventional method where the motor load is detected indirectly from variation of rotation speed or current value. In addition, adjustment of spring constant ensures high accuracy of the obstacle detection, as well as limit detection. Moreover, a fixing member for fixing the load detecting spring can be used as the spring constant adjusting member, so that reduction of the number of components and simplification of the structure can be achieved.
Preferably, the load detecting spring of the present invention is formed substantially in U-shape or linear shape.
The displaceable member of the present invention can be structured such as to be pivoted to the motor shaft and able to rotate around the axis of the motor shaft. Rotational displacement of the displaceable member in accordance with the load variation can be detected by the displacement sensor.
Furthermore, the displaceable member of the present invention can be structured such as to be pivoted to the fixed shaft and able to rotate around the axis of the fixed shaft. Rotational displacement of the displaceable member in accordance with the load variation can be detected by the displacement sensor.
REFERENCES:
patent: 4827199 (1989-05-01), Kaucic et al.
patent: 6125907 (2000-10-01), Tokuyama et al.
patent: 10-82261 (1998-03-01), None
Otsuka Yoshihiro
Tokuyama Noriaki
Arent Fox Kintner & Plotkin & Kahn, PLLC
Johnson Blair M.
Sanwa Shutter Corporation
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