Lock and emergency release system for power operated doors

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to power operated doors and, more particularly, to a lock and emergency release system operable to allow manual movement of such doors under emergency conditions.

2. Description of the Prior Art

Sometimes a power operated sliding door must be prevented from opening, because of a flaw in the door. This is normally done using a standard manual locking mechanism which has to be locked and unlocked using a key. In an emergency, the manual locking mechanism has first to be unlocked with the key and then an emergency release handle can be pulled to release the door from its associated door operator so as to allow the door to be subsequently manually displaced to an open position thereof. This system can be very dangerous in the case of an emergency because a key is required to open the door if the same has been previously locked to prevent operation thereof by the door operator. Furthermore, two operations are required to unlock the door, thereby increasing the time required to open the door.

Accordingly, there is a need for a new door emergency release system which is adapted to simultaneously unlock a power operated door and release the same from its associated door operator without the necessity of a key.

SUMMARY OF THE INVENTION

It is therefore an aim of the present invention to provide a new lock and emergency release system for a power operated door.

It is also an aim of the present invention to provide such a lock and emergency release system which is adapted to enable a normally power operated door to be manually moved to an open position even when the door has been previously locked against opening by the door operator.

It is a further aim of the present invention to provide a relatively simple and reliable lock and emergency release system.

Therefore, in accordance with the present invention, there is provided a lock and emergency release system for a door normally power operated by a door operator, the system comprising a lock displaceable between an idle position to a functional position in which the door operator is prevented from opening the door, at least one emergency release means manually operable for displacing said lock to said idle position thereof and releasing the door from said door operator, thereby allowing the door to be manually opened.

BRIEF DESCRIPTION OF THE DRAWINGS

Having thus generally described the nature of the invention, reference will now be made to the accompanying drawings, showing by way of illustration a preferred embodiment thereof, and in which:

FIG. 1

is a perspective view of a lock and emergency release system in accordance with a first embodiment of the present invention;

FIG. 2

is a top plan view of a main portion of the mechanism of the lock and emergency release system of

FIG. 1

;

FIG. 3

is a perspective view of the main portion of the mechanism illustrated in

FIG. 2

;

FIG. 4

is a perspective view of a pulley forming part of the mechanism illustrated in

FIGS. 1

to

3

;

FIG. 5

is a perspective view of a key drum of a lock forming part of the lock and emergency release system of

FIG. 1

;

FIGS. 6 and 7

are top plan views of a drum spring mechanism used to releasably retain the key drum illustrated in

FIG. 5

in locked and unlocked positions thereof;

FIGS. 8

to

11

are schematic front elevational views of the system of

FIG. 1

, illustrating the operation of the system;

FIGS. 12 and 13

are enlarged front elevational views of the key drum and the main pulley of the system, illustrating how the drum key is rotated from a locked position to an unlocked position by the pulley when an emergency release handle is pulled; and

FIGS. 14 and 15

are enlarged front elevational views of the key drum and the main pulley of the system illustrating how the pulley is disconnected from the key drum when the same is in an unlocked position thereof.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

FIG. 1

illustrates a lock and emergency release system

10

for use with a sliding door (not shown) normally displaced between closed and open positions by a conventional powered door operator partly shown at

12

. The door operator

12

can be of the type typically used in a commuter train or the like for operating all the side doors of the train from a single remote location.

The lock and emergency release system

10

generally includes a lock mechanism

14

for physically preventing sliding movement of the door towards an open position, for instance, when the door has been damaged, and an emergency-release door mechanism

16

, which is operable to simultaneously unlock the lock mechanism

14

and release the sliding door from the power operator door mechanism

12

so as to enable manual movement of the door under emergency conditions.

The door operator

12

includes a linkage (not shown) operatively connected to the door to effect movement thereof in response to the pivotal movement of an arm

18

pivotally mounted at

20

. An electromagnetic unit

22

is provided to pivot the arm

18

between a lock position, as seen in

FIG. 1

, for closing the door and an unlocked position in which the arm

18

is pivoted away from the electro-magnetic unit

22

so as to cause the door to be opened by the linkage.

The lock mechanism

14

and the emergency-release door mechanism

16

are housed in a casing

24

adapted to be mounted to an interior wall

26

adjacent an opening defined therein for receiving the sliding door. A cover

28

is hinged to the casing

24

along a longitudinal edge thereof for selectively preventing and providing access to the interior of the casing

24

. A lock (not shown) is provided to normally lock the cover

28

in the closed position thereof. A glass plate

30

is provided to cover an opening defined in the cover

28

. The glass plate

30

is adapted to be broken to provide access to an emergency release handle

32

, which is adapted to be operated to release the door, regardless of the respective conditions of the door operator

12

and the lock mechanism

14

, as will be seen hereinafter.

An inclined mounting plate

34

is secured to a bottom wall

36

of the casing

24

for providing a mounting surface for the lock mechanism

14

and the emergency-release door mechanism

16

.

The lock mechanism

14

includes a key drum

38

operable to reciprocate a latch bolt

40

between retracted and extended positions in a direction generally perpendicular to the plane of the sliding door. The drum

38

defines a key hole

42

for receiving a key, which is, in turn, adapted to be operated to rotate the drum

38

between locked and unlocked positions to effect displacement of the latch bolt

40

. The drum

38

extends through the mounting plate

34

and is axially retained thereon by a drum retainer

44

secured at one end of the drum

38

on a back side of the mounting plate

34

, as seen in FIG.

2

.

Referring to

FIGS. 6 and 7

, it can be seen that the drum retainer

44

has four peripheral semi-circular recesses

46

distributed along the circumference thereof. A one piece spring clip

48

having a pair of inwardly spring loaded arms

50

connected by an integral loop segment

52

extending about a fixed pin

54

, is provided for engagement in diametrically opposed pairs of recesses

46

in order to releasably maintain the drum

38

in one of the unlocked and locked positions thereof. Upon rotation of the drum

38

from its locked position, as illustrated in

FIG. 6

, the spring-loaded arms

50

of the clip

48

will be pushed out of the recesses

46

a

against their respective biasing forces, as seen in

FIG. 7

, thereby allowing the drum

38

to be rotated to its unlocked position. Once the drum

38

will have been rotated to its unlocked position, the arms

50

, because of their resilient nature, will fall in the second pair of diametrically opposed recesses

46

b

, thereby releasably retaining the drum

38

in its unlocked position. Accordingly, it is only required to overcome the biasing forces of the spring-loaded arms

50

to rotate the drum

38

between the unlocked and locked positions.

As seen in

FIGS. 1 and 3

, an axially extending pin

56

, secured to the drum

38

, is engaged in a slot

58

defined at an inner end of the latch bolt

40

and extending perpendicularly relative thereto. The rotation of the drum

38

will thereby cause the latch bolt

40

to slide linearly relative to the casing

24

. A longitudinal slot

60

is defined along a portion of the length of the bolt

40

for receiving a fixed guide pin

62

projecting at right angle from the mounting plate

34

.

A bolt head

64

is provided at the outer end of the bolt

40

to physically interfere and prevent the opening of the sliding door when the bolt

40

is displaced to the extended position thereof. The bolt head

64

is adapted, when the bolt

40

is extended, to extend across the mouth of a door receiving pocket (not shown) in which the door is received when displaced to its open position.

Limit switches (not shown) are provided to detect the position of the bolt

40

in order to cut power to the door operator

12

when the bolt

40

is displaced to its extended position, thereby disabling the door operator

12

to prevent powered movement of the door in addition to the physical interfering action provided by the bolt head

64

.

As seen in

FIGS. 1

to

4

, the emergency release door mechanism

16

includes a driven pulley

66

which is rotatably mounted about the key drum

38

. The pulley

66

is drivingly connected to the emergency release handle

32

by means of a cable

68

secured at one end thereof to the periphery of the pulley at

70

and at the opposed end thereof to the emergency release handle

38

. The cable

68

extends over a portion of the pulley

66

in a circumferentially extending groove

72

defined therein and then over a guide pulley

74

mounted about a pin

76

extending at right angle from the mounting plate

34

in parallel to the key drum

38

. The cable

68

extends from the guide pulley

74

to a second guide pulley

78

mounted for rotation about an axis perpendicular to the pin

76

and the drum

38

. The cable

68

then extends to the release handle

32

which is, in turn, mounted for pivotal movement about a pivot pin

80

extending in parallel to the plane of the mounting plate

34

and the rotation axis of the second guide pulley

78

. A spring

82

(see

FIG. 2

) is disposed about the pivot pin

80

to normally bias the handle

32

towards the mounting plate

34

in an idle position thereof.

In the event that the handle

32

is pulled away from the mounting plate

34

, the cable

68

will impart a tangential force on the pulley

66

, thereby causing the same to rotate in a counterclockwise direction. The motion imparted to the pulley

66

is transmitted to the door operator

12

via a cable

84

extending in a closed loop over the pulley

66

in a second circumferentially extending groove

86

defined therein and over another pulley

88

mounted on an idle pin

90

located in the vicinity of the arm

18

and the electromagnetic unit

22

of the door operator

12

. As seen in

FIG. 1

, the arm

18

is clipped at a distal end thereof to the cable

84

and, thus, movement of the cable

84

will be transmitted to the arm

18

and vice versa. Therefore, when the electromagnetic unit

22

is operated to pivot the arm

18

away therefrom in order to open the door, a motion is transmitted to the pulley

66

, thereby creating a slack in the cable

68

between the handle

32

and the pulley

66

, as seen in FIG.

11

. Therefore, the handle

32

will remain inert.

In the event that the door is closed and that someone pulls the emergency release handle

32

, the pulley

66

will rotate in a counterclockwise direction to cause the cable

84

to pull the arm

18

away from the electromagnetic unit

22

, thereby releasing the door from the door operator

12

and allowing manual opening of the door.

The emergency release door mechanism

16

further includes a clutch mechanism for selectively connecting and disconnecting the pulley

66

and the drum

38

. More specifically, as seen in

FIG. 4

, the pulley

66

has a semi-cylindrical recess

92

defined in an internal circumferential surface thereof for receiving a torque transferring member provided in the form of a cylinder

94

(see

FIGS. 12

to

15

). The cylinder

94

is trapped in the recess

92

between the pulley

66

and the drum

38

and is constrained to move in a cutout portion

96

defined along about a quarter of the circumference of the drum

38

, as seen in

FIGS. 12

to

15

.

By turning the drum

38

in a clockwise direction to a locked position so as to displace the bolt

40

to the extended position thereof, as illustrated in

FIG. 8

, the cylinder

94

is placed in abutment with one end of the cutout portion

96

(see

FIG. 12

) so that subsequent rotation of the pulley

66

in a counterclockwise direction will cause the drum

38

to rotate therewith. Accordingly, if the emergency handle

32

is subsequently pulled with a view of opening the door, the cable

68

will cause the pulley

66

to rotate in a counterclockwise direction, thereby causing the drum

38

to rotate to an unlocked position thereof to produce the retraction of the bolt

40

, as illustrated in

FIGS. 10 and 13

. Simultaneously, the rotation of the pulley

66

will cause the endless cable

84

to act on the arm

18

to pivot the same away from the electromagnetic unit

22

, thereby releasing the door from the door operator

12

.

Thereafter, if the door operator

12

is activated back to close the door, the arm

18

will pivot towards the electromagnetic unit

22

, as seen in

FIG. 9

, thereby causing the pulley

66

to rotate in a clockwise direction without driving the drum

38

, as seen in FIG.

14

. While the drum

38

is in its unlocked position, the door operator

12

can be activated to open and close the door and the pulley

66

will rotate without driving the drum

38

because the cylinder

94

in displaced within the limits of the cutout portion

96

. If the emergency handle

32

is pulled while the door is opened (i.e. when there is a slack in the cable

68

, between the handle

32

and the pulley

66

, as seen in

FIG. 11

) the cable

68

will only become stretched. However, when the door is closed, the cable

68

is stretched and if a person pulls on the handle

32

, the pulley

66

will rotate in a counterclockwise direction about the drum

38

from the position illustrated in

FIG. 14

to the position illustrated in

FIG. 15

, thereby causing the cable

84

, which runs in a closed loop, to pivot the arm

18

away from the electromagnetic unit

22

to a position wherein the door is released from the door operator

12

.

As seen in

FIG. 1

, an outer emergency handle

98

can be provided on an opposite side of the door for allowing someone to release the door from the door operator

12

and unlock the lock

14

from outside of the enclosure closed by the door. The outer emergency handle

98

is directly connected to the arm

18

via a cable

100

and is thus effective for driving the pulley

66

via the cable

84

, according to the above description.