Automatic sliding door system for refrigerator unit

• US 20010030606A1
• Filed: 03/05/2001
• Published: 10/18/2001
• Est. Priority Date: 09/29/1999
• Status: Active Grant

• Current Assignee: Refrigerator Manufacturers, LLC
• Original Assignee: Refrigerator Manufacturers, Inc.
• Inventors: Riddle, John, Jaffe, Lawrence, Becker, Richard
• Granted Patent: US 6,525,659 B2
• Time in Patent Office: Days
• US Class Current: 340/545.6
• CPC Class Codes: E05F 15/43 responsive to disruption of energy beams, e.g. light or sound
• CPC Class Codes: E05F 15/73 responsive to movement or presence of persons or objects
• CPC Class Codes: E05F 2015/434 with cameras or optical sensors
• CPC Class Codes: E05F 2015/487 Fault detection of safety edges
• CPC Class Codes: E05Y 2800/106 Lighting
• CPC Class Codes: E05Y 2800/40 Protection E05Y2400/50, E05Y2400/52 take precedence
• CPC Class Codes: E05Y 2900/102 for cold-rooms
• CPC Class Codes: F25D 23/021 Sliding doors
• CPC Class Codes: G01S 13/56 for presence detection presence detection using near field arrangements G01V3/00, e.g. G01V3/08, G01V3/12; burglar, theft or intruder alarms with electrical actuation G08B13/22 - G08B13/26

Abstract

An automatic sliding door system especially well suited for use in walk-in freezer or refrigerator units includes an exterior sensor unit for detecting opening conditions on the exterior of a freezer or refrigerator unit, and an interior sensor unit for detecting opening conditions in the interior of the freezer or refrigerator unit. Each sensor unit comprises both a motion sensor and a presence detector. The motion sensor detects motion towards the sliding doors, and opens the doors as they are approached. Once motion is detected, the motion sensor tracks the motion no matter whether towards or away from the door, and keep the doors open so long as the motion is present. The presence detector of each sensor unit detects a change in the ambient conditions directly underneath the doorway, and keeps the door open when the ambient conditions change. The right and left side doors that are opened and closed simultaneously and in synchronism using a pulley mechanism connected to both the right and left side doors. A brushless DC servo motor is preferably employed to move the pulley and thereby open and close the doors. Optical sensors are deployed above one or both doors at selected locations so as to indicate deceleration and stopping points for the doors. Safety and security features include a manual push plate or pushbutton, a key lock on the exterior of the unit, and a multi-tier alarm system.

Claims

1. An automatic sliding door system, comprising:

an insulated door frame, adapted for placement between a walk-in freezer or refrigerator and the exterior thereof;

a bi-parting door connected to said insulated door frame, said bi-parting door comprising a right door and a left door, each slidably connected to said insulated door frame;

a motor for synchronously opening said right door and left door;

an exterior sensor unit mounted on said door frame, said exterior sensor unit comprising an exterior motion sensor;

an interior sensor unit mounted on said door frame, said interior sensor unit comprising an interior motion sensor; and

a controller electrically connected to said exterior sensor unit, said interior sensor unit, and said motor, said controller causing said motor to energize in response to a movement detection signal from either said exterior sensor unit or said interior sensor unit.

2. The automatic sliding door system of

claim 1

, wherein

said exterior sensor unit further comprises an exterior presence detector, said exterior presence detector positioned so as to view in a downward grid from atop said insulated door frame;

and

said interior sensor unit further comprises an interior presence detector, said interior presence detector positioned so as to view in a downward grid from atop said insulated door frame;

wherein said controller causes said motor to energy in response to a presence detection signal from either said exterior sensor unit of said interior sensor unit.

3. The automatic sliding door system of

claim 1

, wherein said exterior motion sensor and said interior motion sensor each generate a motion detection signal only when detecting motion towards the bi-parting door, but thereafter continues to generate said motion detection signal until motion in any direction within a detection field of said exterior motion sensor or interior motion sensor is no longer detected.

4. The automatic sliding door system of

claim 1

, wherein said motor comprises a brushless DC servo motor, wherein said insulated door frame comprises a left frame sidewall, a right frame sidewall, and a frame crossbeam, and wherein the automatic sliding door system further comprises:

a track affixed to said frame crossbeam;

a first pair of roller brackets connected to said right door, said roller brackets comprising rollers adapted for motion along said track whereby said right door slides open and shut;

a second pair of roller brackets connected to said left door, said roller brackets comprising rollers adapted for motion along said track whereby said left door slides open and shut;

a pair of pulley wheels affixed to said frame crossbeam, said brushless DC servo motor connected to one of said pulley wheels;

a pulley securely wrapped around said pulley wheels, whereby rotation of said pulley wheels causes said pulley to rotate;

a first extension connecting said right door to one side of said pulley and a second extension connecting said left door to another side of said pulley, whereby said brushless DC servo motor causes said right door and left door to open and shut in synchronicity when turning said one pulley wheel; and

a plurality of optical detectors, each optical detector located at a different position along at least one of said right door and said left door, said optical detectors electrically connected to said controller, whereby said controller determines when to energize, decelerate and stop said motor.

5. The automatic sliding door system of

claim 1

, further comprising manual activation means located internally to said walk-in freezer or refrigerator for causing said controller to energize said motor so as to open said bi-parting door.

6. The automatic sliding door system of

claim 1

, further comprising an alarm connected to said controller, wherein said controller causes said alarm to produce different alarm signals based upon different alarm conditions.

7. The automatic sliding door of

claim 6

, wherein said controller causes said alarm to produce a first alarm signal when said right door or left door is jammed, a second alarm signal upon occurrence of an error relating to said optical detectors, and a third alarm signal when said bi-parting door is manually opened or movement is detected by said interior motion sensor within said walk-in freezer or refrigerator after said bi-parting door has been locked.

8. An automatic sliding door system, comprising:

an insulated door frame, adapted for placement between a walk-in freezer or refrigerator and the exterior thereof, said insulated door frame comprising a left frame sidewall, a right frame sidewall, and a frame crossbeam;

a track affixed to said frame crossbeam;

a right door;

a first pair of roller brackets connected to said right door, said roller brackets comprising rollers adapted for motion along said track whereby said right door slides open and shut;

a left door;

a second pair of roller brackets connected to said left door, said roller brackets comprising rollers adapted for motion along said track whereby said left door slides open and shut;

a pair of pulley wheels affixed to said frame crossbeam;

a pulley securely wrapped around said pulley wheels, whereby rotation of said pulley wheels causes said pulley to rotate;

a first extension connecting said right door to one side of said pulley;

a second extension connecting said left door to another side of said pulley;

a brushless DC servo motor connected to one of said pulley wheels, whereby said right door and left door are open and shut in synchronicity when said brushless DC servo motor turns said one pulley wheel;

a controller electrically connected to said brushless DC servo motor; and

a plurality of optical detectors, each optical detector located at a different position along at least one of said right door and said left door, said optical detectors electrically connected to said controller, whereby said controller determines when to energize, decelerate and stop said brushless DC servo motor.

9. The automatic sliding door system of

claim 8

,

wherein said plurality of optical detectors comprises a first optical detector positioned at a deceleration point for opening said right door and left door, a second optical detector positioned at an at-rest point when said right door and left door are fully open, a third optical detector positioned at a deceleration point for closing said right door and left door, and a fourth optical detector positioned at an at-rest point when said right door and left door are fully closed, each optical detector providing an electrical signal to said controller indicating whether said at least one door is present or not present in its detection field;

and

wherein said controller causes said brushless DC servo motor to decelerate when said at least one door reaches either said first optical detector or said third optical detector, and to stop when said at least one door reaches either said second optical detector or said fourth optical detector.

10. An automatic sliding door system for use in a walk-in freezer or refrigerator, comprising:

an insulated door frame, adapted for placement between a walk-in freezer or refrigerator and the exterior thereof, said insulated door frame comprising a left frame sidewall, a right frame sidewall, and a frame crossbeam;

a track affixed to said frame crossbeam;

a right door;

a first pair of roller brackets connected to said right door, said roller brackets comprising rollers adapted for motion along said track whereby said right door slides open and shut;

a left door;

a second pair of roller brackets connected to said left door, said roller brackets comprising rollers adapted for motion along said track whereby said left door slides open and shut;

an exterior sensor unit mounted atop said frame crossbeam, said exterior sensor unit comprising an exterior motion sensor and an exterior presence detector, said exterior presence detector forming a first infrared detection grid downward beneath said frame crossbeam and at least partly internal to said walk-in freezer or refrigerator;

an interior sensor unit mounted atop said frame crossbeam, said interior sensor unit comprising an interior motion sensor and an interior presence detector, said interior presence detector forming a second infrared detection grid downward beneath said frame crossbeam and at least partly external to said walk-in freezer or refrigerator;

a pair of pulley wheels affixed to said frame crossbeam;

a pulley securely wrapped around said pulley wheels, whereby rotation of said pulley wheels causes said pulley to rotate;

a first extension connecting said right door to one side of said pulley;

a second extension connecting said left door to another side of said pulley;

a brushless DC servo motor connected to one of said pulley wheels;

a controller electrically connected to said exterior sensor unit and to said interior sensor unit, said controller energizing said brushless DC servo motor upon detection by said exterior sensor unit or said interior unit of either movement within a field of view of said exterior motion detector or said interior motion detector, or a presence within said first infrared detection grid or said second infrared detection grid; and

a plurality of optical detectors, each optical detector located at a different position along at least one of said right door and said left door, said optical detectors electrically connected to said controller, whereby said controller determines when to energize, decelerate and stop said brushless DC servo motor.