Machine element or mechanism – Mechanical movements – Reciprocating or oscillating to or from alternating rotary
Reexamination Certificate
1999-09-28
2001-09-04
Bucci, David A. (Department: 3682)
Machine element or mechanism
Mechanical movements
Reciprocating or oscillating to or from alternating rotary
C049S362000
Reexamination Certificate
active
06282970
ABSTRACT:
FIELD OF THE INVENTION
The present invention relates, in general, to screw drive mechanisms and, more particularly, this invention relates to a passenger transit type vehicle door system employing a screw drive mechanism.
BACKGROUND OF THE INVENTION
Drive systems for passenger transit type vehicle doors must meet a number of conflicting requirements, as is generally well known in the passenger transit industry. For example, these doors must open and close rather quickly and smoothly upon receipt of a control signal to open or close. Additionally, these doors must have a positive lock to prevent them from being inadvertently opened when the transit vehicle is in motion. On the other hand, such doors require a manual release to unlock and open them in the event of an emergency.
SUMMARY OF THE INVENTION
In one aspect, the present invention provides a screw drive mechanism connectable to a first machine portion and to a second machine portion for moving the second machine portion relative to the first machine portion from a first position to a second position. The mechanism includes a base for attachment to the first machine portion and a motor attached to the base. Additionally, the screw drive mechanism includes a drive screw having a rotary motion connection to the motor to be rotated thereby and a drive nut having an internally threaded bore engaged with the drive screw to receive a drive force from the drive screw. A drive nut connection is engaged with the drive nut for conveying the drive force to the second machine portion. An anti-rotation member is attached to the drive nut connection which engages the drive nut to prevent rotation of such drive nut. The drive screw mechanism also includes an activation member attached to the base. Such activation member contacts a disengaging surface portion of the anti-rotation member when the second machine portion is moved to the second position to place the anti-rotation member in a position disengaged from the drive nut so that the drive nut may rotate. A drive nut rotating device is attached to the base for rotating the drive nut to a locking position when the second machine portion is moved to the second position.
In another aspect, the invention provides a screw drive mechanism for a transit vehicle door for moving the door from an open position to a closed position. The screw drive mechanism includes a base for attachment to the transit vehicle and a motor attached to the base. It has a drive screw having a rotary motion connection to the motor to be rotated thereby and a drive nut having an internally threaded bore engaged with the drive screw to receive a drive force from the drive screw. A drive nut connection is engaged with the drive nut to convey the drive force to the door. An anti-rotation member is attached to the drive nut connection for engaging the drive nut to prevent rotation of such drive nut. An activation member is attached to the base which is in contact with a disengaging surface portion of the anti-rotation member when the door is moved to the closed position to place the anti-rotation member in a position disengaged from the drive nut so that the drive nut may rotate. The mechanism further includes a drive nut rotating device attached to the base. Such drive nut rotating device rotates the drive nut to a locking position when the door is moved to the closed position.
OBJECTS OF THE INVENTION
It is, therefore, one of the primary objects of the present invention to provide a passenger transit type vehicle door system having a motor and a door which is opened, closed and locked by the motor.
Another object of the present invention is to provide a passenger transit type vehicle door system having a door and a motor in which the door is locked when the motor moves it to a closed position.
Still another object of the present invention is to provide a passenger transit type vehicle door system having a manual release mechanism which can unlock the door and the system being back driveable to open the door upon activation of the manual release mechanism.
Yet another object of the present invention is to provide a passenger transit type vehicle door system which, when closed, cannot be reopened without an activation of a manual release mechanism.
A further object of the present invention is to provide a passenger transit type vehicle door system which has a first manual release for use by persons inside the vehicle and a second manual release for rescue personnel outside the vehicle.
An additional object of the present invention is to provide a passenger transit type vehicle door system which is moved to a locked position by a motor which opens and closes the door.
Yet a further object of the present invention is to provide a passenger transit type vehicle door system having a drive nut which is rotated to a locking position upon movement of the door to the closed position.
Still another object of the present invention is to provide a passenger transit type vehicle door system which can accommodate misalignment between a door support rod and a drive screw for the door.
It is another object of the present invention to provide a passenger transit type vehicle door lock in which a force on the door in the opening direction will force the locking components more firmly into the locked position.
It is yet another object of the present invention to provide a passenger transit type vehicle door lock in which compression of resilient seals at the edges of the door forces the locking components more firmly into the locked position.
In addition to the various objects and advantages of the present invention which have been generally described above, there will be various other objects and advantages of the invention that will become more readily apparent to those persons who are skilled in the relevant art from the following more detailed description of the invention, particularly, when the detailed description is taken in conjunction with the attached drawing figures and with the appended claims.
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patent: 6134838 (2000-10-01), Reddy
Bucci David A.
Hansen Colby
James Ray & Associates
Westinghouse Air Brake Company
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