Electricity: motive power systems – Automatic and/or with time-delay means
Reexamination Certificate
2001-10-18
2003-12-23
Masih, Karen (Department: 2837)
Electricity: motive power systems
Automatic and/or with time-delay means
C318S460000, C318S466000, C318S469000
Reexamination Certificate
active
06667591
ABSTRACT:
TECHNICAL FIELD
Generally, the present invention relates to a garage door operator system for use on a closure member moveable relative to a fixed member. More particularly, the present invention relates to an operator-controlled motor for controlling the operation of a closure member, such as a gate or door, between a closed position and an open position. More specifically, the present invention relates to an operator-controlled motor for a door or gate operator, wherein additional power is allowed by the motor to overcome hindrances in door movement.
BACKGROUND ART
For convenience purposes, it is well known to provide garage doors which utilize a motor to provide opening and closing movements of the door. Motors may also be coupled with other types of movable barriers such as gates, windows retractable overhangs and the like. An operator is employed to control the motor and related functions with respect to the door. The operator receives command signals for the purpose of opening and closing the door from a wireless remote, from a wired wall station or other similar device. It is also known to provide safety devices that are connected to the operator for the purpose of detecting an obstruction so that the operator may then take corrective action with the motor to avoid entrapment of the obstruction.
Safety devices come in many forms for use with a garage door operator. One of the more widely used devices is a photo-electric eye which projects a light beam across the door's travel path. If the light beam is interrupted during closure of the door, the operator stops and/or stops and reverses the travel of the door. This is sometimes referred to as a non-contacting or an external safety device. Contact type safety devices such as an edge-sensitive pressure switch, which is attached to the bottom edge of the door and runs the complete width of the door, may also be used. Other contact safety devices directly monitor the operating characteristics of the driving motor to determine whether an obstruction is present. Typically, shaft speed of the motor is monitored by projecting an infrared light through an interrupter wheel. Alternatively, Hall effect switches or tachometers can be used to monitor shaft speed. Or, the motor current could be monitored such that when an excessive amount of current is drawn by the motor—which indicates that the motor is working harder than normal—it is presumed that an obstruction has been encountered. It is also known to monitor door speed with a sliding potentiometer, wherein a rate of change is equated to the speed of the door and wherein unexpected slowing of the door triggers corrective action by the operator. Regardless of how the safety devices work, their purpose is to ensure that individuals, especially children, are not entrapped by a closing door. Opening forces of the door are also monitored to preclude damage to the operating system for instances where an object or individual is caught upon a door panel as the door moves upwardly.
How safety devices are used with a door operator system have evolved from the days of no uniform standard to the currently applied government regulations as embodied in Underwriters Laboratories Standard 325. The basic standard requires the use of a fail-safe external safety device, such as a photo-electric eye, that is connected to the operator. Use of the external safety device allows either a wired wall station or a wireless remote control device to send a signal to the operator to close the door when the user exerts a momentary push and release force upon an actuation button. To open the door, one may also use a push and release of the appropriate wall station or remote control switch. If, for whatever reason, the safety device is disabled, a constant pressure force applied to the wall station switch or to a remote control switch in the line of sight of the operator will allow the door to close. It is presumed that the user is watching the path of the door for objects which may be entrapped in the path of the door. The safety standard will not allow the constant application of pressure on a remote device out of the line of sight to close the door. However, momentary pressure on either the remote device switch or the wall station switch will allow the door to open even if the safety system is disabled.
A newer generation of operating systems have been found to provide improved sensitivity to extraneous forces applied to a door during its movement. One such device is disclosed in U.S. Pat. No. 6,161,438, which is assigned to the present assignee of this invention and which is incorporated herein by reference. Briefly, this patent discloses use of a potentiometer coupled to the door for determining a plurality of positional locations between the open and closed positions. A processor contained in the operator correlates the position of the door with an applied force for use in comparison to a predetermined threshold. If, during movement of the door, the applied force is outside the limits of the predetermined threshold, corrective action can be taken. With this increased sensitivity, the safety standard allows use of the above operator system without an external safety system on anti-pinch doors. Anti-pinch doors use sectional panels that preclude the entry of objects, such as fingers, between the door panels during opening and closing cycles. As before, actuation and release of the switch opens and closes the door. Constant pressure on the switch has no affect on the operator. If an obstruction is encountered and a force is exerted which exceeds the threshold, corrective action is taken. However, if a door is a pinch-type door, then the external safety device must be used with the operator. In this embodiment, actuation and release of the switch opens and closes the door. If the external safety device detects an object in the presence of the door path, then corrective action is taken. And if the force required by the motor to move the door exceeds the threshold limit, then the operator also takes corrective action.
With the foregoing in mind, it will be appreciated that controls for a motorized garage door operator regulate the motor speed to a constant velocity of the door. This constant speed can be detrimental to a garage door when the operator first begins to move the door. Accordingly, motor controls have been developed that reduce the voltage supplied to the motor during start-up to allow for a “soft start,” preventing damage to the door and also for a “soft finish.” Some manufacturers use a reduced speed start then ramp up the motor to increase the door speed to minimize door opening time and, sometimes, closing time. Both of the speed adjustments are controlled by the operator's motor controls.
These motorized garage door operators are known to have force adjustments that can be either mechanically or electronically controlled. This allows the installer, or the consumer, a way of adjusting the force that the motor exerts on the door. The amount of force to move the door will vary with the weight of the door, but can also vary as the environment changes and as the door system becomes worn with age. Generally, the information necessary to properly set these limits is contained in the owner's/installation manual. However, in the case of a door frozen to the floor, one must increase the force adjustment to free the door. In the event the adjustment is not reset, the door's safety settings are not what they should be. The same also applies if the door is opened when one of the counter-balance springs are broken and the force limit is not reset after the springs are replaced. Accordingly, there is no safe and secure way to provide additional power to the motor to lift a door frozen to the ground or to accommodate for broken springs in the operator and then to return the door operator system to its preferred operation mode. These conditions or hindrances are especially problematic when ensuring that the operator complies with the aforementioned safety standard. Therefore, there is a need
Mullet Willis Jay
Murray James S.
Masih Karen
Renner Kenner Greive Bobak Taylor & Weber
Wayne-Dalton Corp.
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