Information
-
Patent Grant
-
6357805
-
Patent Number
6,357,805
-
Date Filed
Thursday, September 16, 199924 years ago
-
Date Issued
Tuesday, March 19, 200222 years ago
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Inventors
-
-
Examiners
Agents
-
CPC
-
US Classifications
Field of Search
US
- 049 280
- 049 289
- 049 301
- 049 297
- 292 1
- 292 144
- 292 201
- 292 DIG 12
- 292 DIG 25
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International Classifications
-
Abstract
A device is provided for unlatching a door which is latched into a door frame where the door latch assembly includes an elongate lever arm rotatable about an axis from a first latched orientation to second unlatched orientation. The device includes a cable having a first end attachable to the distal end of the lever arm and a second end attached to a take up spool. The take up spool is rotated by a motor in a first direction to take up the cable and thereby draw the lever arm from the first latched orientation to the second unlatched orientation and thereafter rotate in the second direction to release the cable and allow the lever arm to return from the second unlatched orientation to the first latched orientation.
Description
The present invention relates to door opening devices and, in particular, to a device for releasing the latch on a latched door so that the door can be moved from the closed position to the open position without interference from the latch.
BACKGROUND OF THE INVENTION
In my prior U.S. Pat. No. 5,634,296 I disclosed a device which can be connected between a door and a wall for opening and closing the door. Although the device will reliably move the door between an open position and a closed position, where the door has a latch, the door must also be fitted with some form of latch release. Existing latch releases operate by releasing the latch plate in the wall. Although such latch releases work effectively, they are difficult to install because costly modifications are needed to accommodate the releasable latch plate, and the release solenoid draws conventional AC power such that the device must be wired into the electrical system of the structure.
It would be desirable to provide a latch release device which would not require modifications to the door frame and that would not have to be connected into the AC electric system servicing the structure.
SUMMARY OF THE INVENTION
Briefly, the present invention is embodied a device for unlatching a door which is latched into a door frame where the door latch assembly includes an elongate lever arm rotatable about an axis from a first latched orientation to a second unlatched orientation. The device is attachable to the door and includes a cable having a first end attachable to the distal end of the lever arm and a second end attached to a take up spool. The take up spool is rotated by a motor in a first direction to take up the cable and thereby draw the lever arm from the first latched orientation to the second unlatched orientation and thereafter rotate in the second direction to release the cable and allow the lever arm to return from the second unlatched orientation to the first latched orientation.
The device includes a first detector for detecting when the spool has rotated in a first direction until the lever arm has been drawn to the second orientation, a second detector for detecting when the spool has rotated in the second direction until the lever arm has returned to the first orientation, a third detector for detecting when the door has moved out of the frame, and a start means for starting the unlatching sequence. A logic, which may be in the form of a microprocessor, is responsive to the first detector, the second detector, the third detector, and the start means and directs power to the motor for rotating the spool in the first direction upon actuation of the start means, terminates power to the motor to stop rotation of the spool in the first direction upon receipt of a signal from the first detector, commences power to the motor to rotate the spool in the second direction upon receipt of the signal from the third detector, and terminates power to the motor to stop rotation of the spool upon receipt of a signal from the second detector.
In the preferred embodiment, the first and second detectors comprise cams mounted on the shaft of the spool which engage associated limit switches. The third detector may be any of a number of known devices for detecting when a door has moved out of a closed position, includes detectors associated with door opening devices or a device for assisting in moving a door from a closed orientation to an ajar orientation as disclosed in my patent application filed on Jul. 28, 1999 as Ser. No. 09/362,248.
BRIEF DESCRIPTION OF THE DRAWINGS
A better understanding of the present invention will be had after a reading of the following detailed description taken in conjunction with the drawings wherein:
FIG. 1
is a fragmentary front elevational view of a door having a door opening device fitted thereon;
FIG. 2
is a fragmentary enlarged front elevational view of the door of
FIG. 1
with an unlatching device in accordance with the invention fitted thereon;
FIG. 3
is a side cross-sectional view of the unlatching device shown in
FIG. 2
taken through line
3
—
3
of
FIG. 2
;
FIG. 4
is a cross-sectional view of the unlatching device taken through line
4
—
4
of
FIG. 3
;
FIG. 5
is a side view of a third detector mounted on a door which is in the open condition;
FIG. 6
is a side view of the third detector shown in
FIG. 5
with the door in the closed condition; and
FIG. 7
is a block diagram of the circuit for the unlatching device shown in FIG.
2
.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT
Referring to
FIG. 1
, a door
10
pivots about the axis of pins
12
of hinges to open and closed against a frame
13
which defines the opening in a wall
14
. A door operating device
16
attached to the upper end of the door
10
and to the wall
14
is operated by a start button
18
, which may be an infrared transmitter that sends a signal to a receiver
19
connected to the device
16
. The door is retained in a closed position by a latch
20
having a bolt
22
which extends into a latch plate
24
.
Typically, the latch
20
is fitted with a door knob
21
, which is turned to rotate a key
23
(shown in
FIG. 2
) from a standby orientation in which the bolt
22
extends from the latch
20
to an unlatch orientation in which the bolt is withdrawn into the latch
20
. The latch
20
includes a spring
25
(shown in FIG.
2
), which urges the bolt axially outward of the latch
20
and urges the key
23
and any object attached thereto to rotate towards the standby orientation. To open the door
10
an operator rotates the door knob
21
and key
23
to withdrawn the bolt
22
from the latch plate
24
, after which the door
10
is free to pivot about the pins
12
of the hinges. When the door knob is released, the spring
25
in the latch rotates the key
23
and the connected door knob back to the stand by orientation and urges the bolt
22
axially outward to the latching position.
Referring to
FIGS. 2-4
, in accordance with the present invention, the door knob
21
is removed and is replaced by a lever
26
having a mounting portion
28
which receives the key
23
extending from the latch
20
for operating the bolt
22
. An eye bolt
30
is mounted to the distal end of the lever
26
for receiving one end of a cable
32
, the other end of which is connected to an unlatching device
34
in accordance with the present invention.
The unlatching device
34
has a housing
36
attached to the door
10
by any suitable means such as devices
37
, and in the housing
36
is an idler pulley
38
around which the cable
32
is wrapped, and a take up spool
40
to which the second end of the cable
32
is attached. A DC gear motor
42
on the exterior of the housing
36
rotates the take up spool
40
counter clockwise, as viewed in
FIG. 4
, to take up the cable
32
and draw the lever
26
from a latched orientation, as shown in solid lines in
FIG. 2
, to an unlatched orientation, as shown in broken lines, and rotates the spool
40
in a clockwise direction to release the lever
26
and allow it to return to the latched position. A spring
44
connected between the eye bolt
30
and the cable
32
absorbs shock within the cable
32
to protect the parts from damage when the motor commences or terminates the rotation of the take up spool
40
. As can be seen, the circumference of the spool
40
must be sufficiently large to wrap a length of cable
32
sufficiently long to draw the lever
26
to an unlatched orientation where the bolt
22
is withdrawn from the plate
24
.
Referring to
FIGS. 3 and 4
, a shaft
46
extends from the gear motor
42
through the housing
36
to which the take up spool
40
is attached. Fitted around a portion of the shaft
46
are first and second annular cam members
48
,
50
having cam lobes
52
,
54
respectively. The cam lobes
52
,
54
interact with limit switches
56
,
58
respectively which are attached to the housing
36
. The cam members
48
,
50
each have a central opening sized to fit tightly around the shaft
46
such that the cams will rotate with the shaft
46
during the normal operation of the device, but can be manually rotated with respect to the shaft to alter the positions at which the cam lobes
52
,
54
engage the limit switches
56
,
58
. When properly adjusted, cam lobe
52
will actuate limit switch
56
when the take up spool
40
is rotated counter clockwise until the lever handle
26
is drawn into the unlatched orientation shown in broken lines on FIG.
2
. Similarly, cam lobe
54
will engage limit switch
58
when the take up spool is subsequently rotated clockwise until the lever handle
26
has returned to the latched position shown in solid lines. Cam
48
with lobe
52
and limit switch
56
is, therefore, a first detector for detecting when the level
26
has reached the unlatched orientation and cam
50
with lobe
54
and switch
58
is a second detector for detecting when the lever
26
has returned to the latched orientation.
The device
34
further includes a third detector for detecting whether the door
10
is within the frame
13
. The third detector may be a part of the door operating device
16
, or of a supplemental device which will urge the door
10
from the closed position to an ajar position as disclosed in my patent application filed on Jul. 28, 1999 and assigned Ser. No. 09/362,248.
Referring to
FIGS. 1
,
5
and
6
, the third detector may also be a free standing device such as switch
60
and a hook-shaped pivotable arm
62
for actuating the switch
60
. The arm
62
is urged by a spring
63
toward a first orientation in which the distal end thereof extends around the edge
64
of the door
10
as shown in FIG.
5
. When the door
10
is closed into the opening
13
in a wall
14
, the distal end of the arm
62
contacts the wall
14
and pivots the arm to a second orientation shown in
FIG. 6
, thereby actuating the switch
60
. The switch
60
is activated when the door
10
is closed in the frame
13
and is deactivated when the door
10
moves out of the frame
13
, such that switch
60
is a third detector.
Referring to
FIG. 7
, the device further includes a logic
66
which may be a microprocessor. The logic
66
is connected to receive signals from the first switch
56
, the second switch
58
, the third switch
60
, the receiver
19
of the door operating device
16
, and it controls the direction of electric power to the DC gear motor
42
. When the door is closed and the logic
66
receives a signal from the receiver
19
that the start button
18
has been depressed, the logic
66
will direct power to the gear motor
42
to rotate the take up spool
40
counter clockwise, thereby pulling the cable
32
and drawing the lever
26
downward. The logic
66
continues to direct power to the gear motor
42
until the second limit switch
58
is actuated by the cam
50
at which time the lever arm has reached the second orientation shown in broken lines in FIG.
2
. The bolt
22
has then been withdrawn from the plate
24
, leaving the door unlatched, and the door operating device
16
can move the door
10
out of the frame
13
. As the door moves out of the frame
13
, the spring
63
returns the arm
61
to the orientation shown in FIG.
5
. When the logic
66
receives a signal from the third switch
60
that the door
10
has moved out of the frame
13
, it again directs electric power to the gear motor
42
, this time in the reverse polarity causing the take up spool
40
to rotate in the clockwise direction to unwrap the cable
32
. As the cable
32
is unwrapped, the spring in the latch
20
urges the key
23
and the lever
26
attached thereto to rotate clockwise back towards the standby orientation. The motor
42
continues to rotate in a clockwise direction until lobe
54
on cam
50
interacts with the second limit switch
58
, which occurs when the lever
26
has returned to the latched orientation shown in solid lines in FIG.
2
. When the logic
66
receives a signal from the limit switch
58
, it will terminate power to the gear motor
42
, thereby returning the device
34
to the standby position.
The operation of the device
34
is commenced only upon receipt of a signal from the receiver
19
and therefore it does not cycle when the door is subsequently closed into the frame
13
. Since the cable
32
does not interfere with the rotation of the lever
26
it does not interfere with the manual operation of the door latch
20
. Also, the device
34
does not draw substantial amounts of power so it can be operated by simple batteries
68
mounted within the housing
36
thereby simplifying the attachment of the device
34
to the door
10
.
There has therefore been disclosed a door unlatching device which can unlatch a door prior to being opened by door opener without requiring alterations to the door frame or the connection of the device into the electrical system of the structure.
While the present invention has been described with respect to a single embodiment, it will be appreciated that many modifications and variations can be made without departing from the true spirit and scope of the invention. It is therefore the intent of the following claims to cover all such modifications and variations which fit within the true spirit and scope of the invention.
Claims
- 1. A device for operating a door latch having a bolt moveable from a latched position to an unlatched position by rotating a key from a first orientation to a second orientation, said device comprisingattachment means for attaching said device to said key, a motor, start means for directing power to said motor, and turning means connected to said motor for turning said key from said first orientation to said second orientation, detector means for detecting when said key has been rotated to said second orientation, and said turning means is response to a signal from said detector means.
- 2. The device of claim 1 wherein said latch includes a spring for urging the rotation of said key towards said first orientation and said device further comprisessecond detector means for detecting when said door has moved out of a door frame, and logic means connected to said motor and said second detector means for releasing said turning means and allowing said spring to return said key to said first orientation after said door has moved out of said door frame.
- 3. The device of claim 2 whereinsaid attachment means includes a lever, said turning means includes a spool and a cable having a first and a second end, said first end of said cable is attached to said lever, said second end of said cable is attached to said spool, and said motor rotates said spool to rotate said key from said first orientation to said second orientation.
- 4. The device of claim 2 and further comprisingthird detector means for detecting when said key has returned to said first orientation, and said logic means is connected to said third detector means for terminating power to said motor after said devices has returned to a standby condition.
- 5. The device of claim 4 and whereinsaid attachment means includes a lever, said turning means includes a spool and a cable having a first end and a second end, said first end of said cable is attached to said lever, said second end of said cable is attached to said spool, and said motor rotates said spool to rotate said key from said first orientation to said second orientation.
- 6. A device for attachment to a door having a door latch having a bolt moveable from a latched position to an unlatched position by rotating a handle from a first orientation to a second orientation, said device comprisingfirst attachment means for attaching device to said handle, second attachment means for attaching said device to said door, a motor, start means for directing power to said motor, turning means connected to said motor for turning said handle from said first orientation to said second orientation, detector means for detecting when said handle has been rotated to said second orientation, and said turning means is responsive to a signal from said detector means.
- 7. The device of claim 6 and further comprisinga lever handle for replacing a knob handle on said door, and said turning means having a cable one end of which is connected to one end of said lever handle.
- 8. The device of claim 7 wherein said turning means further comprises a ratable spool, andsaid cable has a second end connected to said spool.
- 9. The device of claim 6 wherein said latch includes a spring for urging the rotation of said handle towards said first orientation and said device further comprisessecond detector means for detecting when said door has moved out of door frame, and logic means connected to said motor and said second detector means for releasing said turning means and allowing said spring to return said handle to said first orientation after said door has moved out of said door frame.
- 10. The device of claim 9 whereinsaid attachment means includes a lever, said turning means includes a spool and a cable having a first and a second end, said first end of said cable is attached to said lever, said second end of said cable is attached to said spool, and said motor rotates said spool to rotate said key from said first orientation to said second orientation.
- 11. The device of claim 10 and further comprising third detector means for detecting when said key has returned to said first orientation, andsaid logic means connected to said third detector means for terminating power to said motor after said devices has returned to a standby condition.
- 12. The device of claim 11 and whereinsaid attachment means includes a lever, said turning means includes a spool and a cable having a first end and a second end, said first end of said cable is attached to said lever, said second end of said cable is attached to said spool, and said motor rotates said spool to rotate said key from said first orientation to said second orientation.
- 13. A kit for unlatching a door latched into a door frame so that said door may be moved out of said frame, said door having a latch assembly with a handle rotatable about an axis from a first latched orientation to a second unlatched orientation, the kit comprising;a door unlatching device having a housing, means for attaching said housing to said door, a cable having a first end and a second end, means for attaching said first end of said cable to said handle, a take up spool in said housing, said second end of said cable connected to said take up spool, a motor in said housing for rotating said take up spool in a first direction and in a second direction, a first detector for detecting when said handle is in said first orientation, a second detect or for detecting when said handle is in said second orientation, a start means for starting said motor when said door is to be unlatched, a third detector for detecting when said door is out of said door frame, and logic means responsive to said start means, said first detector, said second detector, and said third detector for directing power to said motor to rotate said spool in said first direction upon actuation of said start means, to terminate power to said motor to stop rotation in said first direction upon receipt of a signal from said second detector, to commence power to said motor for rotation of said spool in said second direction upon receipt of a signal from said third detector, and for terminating power to said motor to stop rotation of said spool in said second direction upon receipt of a signal from said first detector.
- 14. The kit of claim 13 and further comprising a lever handle for replacing a knob type handle on said door.
- 15. A device for unlatching a door moveable between a closed position in which said door is in a frame and an open position, in which said door is outside said frame, said door retained in said closed position by a latch having a bolt extended into a latch plate in said frame, said device for withdrawing said bolt from said latch plate by rotating a handle from a first position in which said bolt is extended to a second position in which said bolt is withdrawn, said handle being spring loaded to return from said second position to said first position, said device comprisingmeans for attaching said device to said door, a cable having a first end and a second end, means for attaching said first end of said cable to said handle wherein taking up said second end of said cable will rotate said handle, a spool, said second end of said cable attached to said spool, and a motor drivingly attached to said spool wherein operation of said motor will rotate said spool to take up said cable and rotate said handle.
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A |
898865 |
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Sep 1908 |
A |
959615 |
Schurrmacher |
May 1910 |
A |
1328979 |
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Jan 1920 |
A |
1674662 |
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Jun 1928 |
A |
5095654 |
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A |