Communications: electrical – Condition responsive indicating system – Specific condition
Reexamination Certificate
2001-07-10
2003-10-07
Mullen, Thomas (Department: 2632)
Communications: electrical
Condition responsive indicating system
Specific condition
C187S390000, C187S391000
Reexamination Certificate
active
06630886
ABSTRACT:
TECHNICAL FIELD
This invention relates to improving mechanic safety while performing elevator maintenance.
BACKGROUND ART
Elevator mechanics are typically required to perform periodic maintenance that requires they be on top of the car. The mechanic is further required to operate the car from this position through a top of car inspection station
10
, the front panel
12
of which is shown in FIG.
1
. Elevators typically operate at speeds in the range of 0.5 to 9 m/s. These speeds would make it difficult for the mechanic to perform inspections or to position the car for maintenance. Therefore a slower inspection speed is provided in accordance with the governing safety regulations. In addition to operating the car at inspection speed the top of car inspection station provides the mechanic with sole control over car motion and makes the car unavailable to respond to calls.
The mechanic must access the top of the car by following prescribed safety procedures, which require the mechanic to press the stop switch
16
prior to stepping on top of the car. Once on top of the car the mechanic is required to place the car in the inspection mode by placing the inspection switch
14
in the inspection position
28
.
To move the car the mechanic must first deactivate the stop switch
16
, activate the common switch
18
then simultaneously activate either the car-up
20
or car-down switch
22
depending on the desired direction of travel.
The common switch
18
is provided to ensure that inadvertent activation of either the car-up or car-down switch alone does not cause unintended car motion. The stop switch
16
is provided to prevent any movement of the car not directed by the mechanic and is required to be activated whenever the car is not being moved.
However, the current practice requires the mechanic to remember to activate the stop switch
16
. There is no signal or warning should the mechanic fail to activate the stop switch
16
, which could lead to unanticipated movement of the elevator car, in the event of failure of the inspection mode circuit.
DISCLOSURE OF INVENTION
Objects of the invention include provision of an improved top of car inspection station that provides a signal indicating the stop switch is not activated whenever the car is in the inspection mode and is not being moved by the mechanic.
According to the present invention, the top of the car inspection station includes a warning circuit that includes an alarm that is activated whenever the mechanic fails to activate the stop button when not moving the car during inspection mode.
REFERENCES:
patent: 4004655 (1977-01-01), Kraft et al.
patent: 5443142 (1995-08-01), Glaser
patent: 5644111 (1997-07-01), Cerny et al.
patent: 5721403 (1998-02-01), Hoppie et al.
patent: 5749443 (1998-05-01), Romao
patent: 5773771 (1998-06-01), Chatham
patent: 6202797 (2001-03-01), Skolnick et al.
patent: 6223861 (2001-05-01), Sansevero
patent: 11-301940 (1999-11-01), None
Mullen Thomas
Otis Elevator Company
LandOfFree
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