Elevator structure and brake system therefor
A braking system and method for an apparatus or vehicle moved along a pathway by an apparatus drive mechanism, for halting the movement of the apparatus or vehicle in the event that the drive mechanism loses power or malfunctions. A conveyance system includes a pathway, an moving apparatus moving along the pathway, the apparatus drive mechanism, a brake rail along the pathway having along one edge a multiplicity of regularly spaced teeth with gaps between successive teeth, and a brake device mounted securely to the apparatus. The brake device includes a rotatably driven rotor having outer helical threads for running the gaps in the brake rail with successive turns of the driven rotor without touching the teeth.
1. A method for operating a movable apparatus along a structure that defines a vertical pathway, and for stopping the movable apparatus along the pathway, the movable apparatus supported for movement along the vertical pathway, comprising the steps of:
(a) providing a brake rail secured to the structure along the vertical pathway, the brake rail having along one edge thereof a multiplicity of regularly spaced teeth that define gaps between successive teeth;
(b) providing a brake device secured to the movable apparatus, the brake device including a rotor having an outer cylindrical surface and a central axis of rotation, and including a helical thread on the outer cylindrical surface for loosely engaging the gaps in the brake rail,
(c) providing an apparatus drive mechanism for powering the vertical movement of the movable apparatus;
(d) moving under power the movable apparatus along the pathway;
(e) rotating the rotor so that the thread loosely engages successive gaps in the brake rail and out of contact with the teeth of the brake rail during movement of the moveable apparatus;
(f) moving the movable apparatus under power of the apparatus drive mechanism along the pathway to, and stopping and hovering under power at, a stop position, at which the rotor is rotationally stationary; and
(g) rotating the thread of the rotor, with the moveable apparatus in the stop position, into contact and engagement with a top landing surface of a tooth on the brake rail.
2. The method according to claim 1 , further including:
(g) providing a controller, signaling the apparatus drive mechanism to move the movable apparatus along the pathway, and signaling independently a servo motor to rotate the rotor with the movement of the movable apparatus along the pathway.
3. The method according to claim 2 , wherein the step of signaling the apparatus drive mechanism includes signaling the apparatus drive mechanism to move vertically the moveable apparatus at a velocity or acceleration along the pathway, and the step of signaling the servo motor includes signaling the servo motor to rotate the rotor at a rotational velocity or rotational acceleration that moves the advancing thread of the rotor vertically, either upwardly or downwardly, at the exact same velocity or acceleration, at which the apparatus drive mechanism is moving the apparatus vertically along the vertical pathway.
4. The method according to claim 3 , where the rotor is rotated by a servo motor operatively connected to the rotor, and the apparatus drive mechanism comprises at least one linear synchronous motor.
5. The method according to claim 4 , where the controller is a programmable logic controller system.