Drive mechanism for elevator door

Abstract

An elevator car has a drive mechanism mounted in a compact housing on the upper surface of the car. The drive mechanism includes a rotatable drive shaft, around which is mounted a linear actuator block having a plurality of ball bearings, obliquely arranged relative to the shaft, and firmly touching the shaft. Rotation of the shaft by a motor makes the block move linearly along the shaft. A bracket attached to the block carries an elevator door. Rotation of the shaft therefore opens and closes the door. The direction of movement of the block, and hence the door, depends on the direction of rotation of the shaft. The drive mechanism is compact and simple, and can be applied to new elevators or can be used to retrofit existing elevator cars.

What is claimed is: 
     
       1. An elevator car comprising: a) means defining a car housing, the housing having an upper portion,   b) a drive mechanism mounted to the upper portion of the housing, the drive mechanism including a rotatable shaft, means for rotating the shaft, a block defining recesses which contain at least one rollable bearing, the bearing being fixedly mounted in the block and the block being mounted on the shaft such that rotation of the shaft causes the block to slide along the shaft, the block having a bracket attached thereto, wherein the bearing contacts the shaft with a pressure which is substantially uniform for any position of the block along the shaft, and   c) a sliding door, at least a portion of the door being attached to the bracket, wherein rotation of the shaft causes opening and closing of the door.   
     
     
       2. The elevator car of claim 1, wherein the rotating means comprises a motor connected to the shaft by a pulley. 
     
     
       3. The elevator car of claim 1, wherein the rotation of the shaft is controlled by an electronic control module. 
     
     
       4. The elevator car of claim 1, wherein the rotating means comprises a motor connected to the shaft by a pulley, and wherein the rotation of the shaft is controlled by an electronic control module, and wherein the motor, the pulley, and the control module are all contained within a single drive housing. 
     
     
       5. In an elevator car, the car including a housing, a sliding door, and a drive mechanism for moving the door, the improvement wherein the drive mechanism comprises a rotatable shaft, means for rotating the shaft, a block defining recesses which contain at least one rollable bearing, the bearing being fixedly mounted in the block and the block being mounted on the shaft such that rotation of the shaft causes the block to slide along the shaft, the block having a bracket attached thereto, wherein the bearing contacts the shaft with a pressure which is substantially uniform for any position of the block along the shaft, and the door being attached to the bracket, wherein rotation of the shaft causes the door to open and close. 
     
     
       6. The improvement of claim 5, wherein the rotating means comprises a motor connected to the shaft by a pulley. 
     
     
       7. The elevator car of claim 5, wherein the rotation of the shaft is controlled by an electronic control module. 
     
     
       8. The elevator car of claim 5, wherein the rotating means comprises a motor connected to the shaft by a pulley, and wherein the rotation of the shaft is controlled by an electronic control module, and wherein the motor, the pulley, and the control module are all contained within a single drive housing. 
     
     
       9. In an elevator car, the car including a housing, a sliding door, and a drive mechanism for moving the door, the improvement wherein: the drive mechanism is contained within a module which is removably attached to the housing,   the module includes a rotatable shaft, means for rotating the shaft, a block defining recesses which contain at least one rollable bearing, the bearing being fixedly mounted in the block, the block being mounted on the shaft such that rotation of the shaft causes the block to slide along the shaft, the block having a bracket attached thereto, the bracket extending from the module, wherein the bearing contacts the shaft with a pressure which is substantially uniform for any position of the block along the shaft,   and wherein the door is attached to the bracket.   
     
     
       10. A method of retrofitting an elevator car with a drive mechanism, the elevator car having a housing and a slidable door, the method comprising the steps of: a) providing a module which includes a rotatable shaft, means for rotating the shaft, a block defining recesses which contain at least one rollable bearing, the bearing being fixedly mounted in the block and the block being mounted on the shaft such that rotation of the shaft causes the block to slide along the shaft, the block having a bracket attached thereto and extending from the module, wherein the bearing contacts the shaft with a pressure which is substantially uniform for any position of the block along the shaft,   b) mounting the module to the housing, and   c) connecting the bracket to the door.