Thermally actuated dryer door lock

Patent metadata

Field	Value
Publication number	US-10612274-B2
Application number	US-201314377186-A
Country	US
Kind code	B2
Filing date	Feb 7, 2013
Priority date	Feb 10, 2012
Publication date	Apr 7, 2020
Grant date	Apr 7, 2020

Abstract

A thermally actuated lock for an appliance incorporates a fusible material that holds a spring-loaded bolt in retraction. Temperatures that would indicate an appliance fire allow the bolt to extend between the housing and appliance door to lock the appliance door in a closed position.

First claim

What is claimed is:

1. A dryer comprising:
a dryer housing holding a tumbler drum having an interior receiving clothes to be dried, a motor for rotating the tumbler drum, and a heater system providing temperatures in excess of 120 degrees Fahrenheit;
a dryer door hingeably attached to the dryer housing at a hinge side to move between an open position providing access by a user to the interior of the tumbler drum by a swinging outward of a free side of the dryer door opposite the hinge side and a closed position blocking access by the user to the interior of the tumbler drum by a swinging inward of the free side of the dryer door against the dryer housing;
a latch providing a spring detent holding the dryer door in the closed position against forces of impact of clothing agitated by the tumbler drum against an interior of the dryer door but movable to the open position by force solely on the dryer door by the user greater than the forces of impact; and
a lock assembly independent from the latch and attached to one of the dryer housing and the dryer door and operating between the free side of the dryer door and the dryer housing proximate to the dryer door in the closed position and including:
(a) a spring-loaded bolt comprising a spring and a bolt movable between a disengaged position and an engaged position, to allow moving the dryer door to the open position when the spring-loaded bolt is in the disengaged position by the user of the dryer and to irreversibly block opening of the dryer door by the user in response to a spring biasing in the engaged position; and
(b) a fusible material operating when solid to hold the spring-loaded bolt in the disengaged position and thermally communicating with the interior of the tumbler drum to melt in the event of a dryer fire causing the spring-loaded bolt to move to the engaged position and be retained by the spring preventing access by the user to the interior of the tumbler drum during and after the dryer fire;
wherein the fusible material is a metal alloy.

2. The dryer of claim 1 wherein the lock assembly is attached to the dryer housing so that the spring-loaded bolt may extend outward into a strike hole in the dryer door.

3. The dryer of claim 2 wherein the spring-loaded bolt has a thickness greater than 0.02 inches and the strike hole is substantially equal to the spring-loaded bolt thickness.

4. The dryer of claim 1 further comprising a bolt housing received within a hole through a sheet-metal surface of the dryer housing and wherein the bolt housing has a radially extending flange surrounding the hole at a first end of the bolt housing and adapted to be retained against an outer rim of the hole.

5. The dryer of claim 4 further comprising a retainer clip fitting over an outer surface of the bolt housing to slide toward the outer rim of the hole to retain the bolt housing attached to the dryer housing with the outer rim of the hole flanked on opposite surfaces by the radially extending flange and the retainer clip.

6. The dryer of claim 5 wherein the retainer clip is a metal clip having spring-biased cantilevered teeth canted to allow the retainer clip to slide over the outer surface of the bolt housing toward the outer rim of the hole but to resist sliding over the outer surface of the bolt housing away from the outer rim of the hole.

7. The dryer of claim 1 further including an electrical switch activated with movement of the spring-loaded bolt to shut down a fan of the dryer.

8. The dryer of claim 1 wherein the spring is a compression spring fitting coaxially around the bolt.

9. The dryer of claim 1 wherein the fusible material melts into a liquid in the event of the dryer fire.

10. The dryer of claim 1 further including a bolt housing defining a single volume holding the spring-loaded bolt and holding the fusible material within the bolt housing.

11. A method of locking a dryer door of a dryer in the event of fire, the dryer door hingeably attached to a dryer housing at a hinge side to move between an open position providing access by a user to an interior of a tumbler drum receiving clothes to be dried by a swinging outward of a free side of the dryer door opposite the hinge side and a closed position blocking access by the user to the interior of the tumbler drum by a swinging inward of the free side of the dryer door against the dryer housing, a motor for rotating the tumbler drum and a heater system providing temperatures in excess of 120 degrees Fahrenheit and a latch providing a spring detent holding the dryer door in the closed position against forces of impact of clothing agitated by the tumbler drum against an interior of the dryer door but movable to the open position by force solely on the dryer door by the user greater than the forces of impact, the method of locking being through the use of a dryer lock attached to one of the dryer housing and the dryer door and operating between the free side of the dryer door and the dryer housing proximate to the dryer door in the closed position and having:
a housing having an opening at a first end and a base at a second end;
a bolt slidably received within the housing to move between an extended position where the bolt protrudes out from the opening to irreversibly block opening of the dryer door by the user, and a retracted position where the bolt is substantially fully received within the housing to allow moving the dryer door to the open position when the bolt is in the disengaged position by the user of the dryer;
a spring biasing the bolt toward the extended position; and
a fusible material operating in a solid state to join the bolt to the housing when the bolt is in the retracted position;
wherein the fusible material is a metal alloy that has a melting point of above 170 degrees Fahrenheit; wherein the method comprises the steps of:
(1) installing the dryer lock independent from the latch in one of the dryer door and the dryer housing with the bolt in the retracted position so as not to engage between the dryer housing and the dryer door (2) during a normal operation of the dryer, opening and closing the dryer door without engagement of the bolt between the dryer housing and the dryer door;
(3) during a fire in the tumbler drum, melting the fusible material to cause the bolt to extend into engagement between the dryer housing and the dryer door as retained by the spring to prevent the dryer door from opening by the user during and after the fire.

12. The method of claim 11 wherein step (1) inserts the housing through a hole through sheet-metal of the dryer housing until a radially extending flange on the housing surrounding the hole at the first end of the bolt abuts an outer rim of the hole toward the dryer door of the dryer in the closed position.

13. The method of claim 12 further including the step of sliding a retainer clip fitting over an outer surface of the housing toward the outer rim of the hole to retain the housing attached to the dryer housing with the outer rim of the hole flanked on opposite surfaces by the radially extending flange and the retainer clip.

Assignees

• Illinois Tool Works

Inventors

• Kuehn Kurt A
• Morgan Karl S
• Davis Michael W
• Herzog Richard R
• Wong Chong B
• Dam Robert
• Drelicharz John G

Classifications

• D06F58/50

  Responding to irregular working conditions, e.g. malfunctioning of blowers · CPC title

• E05B65/104 Primary

  actuated in response to heat, e.g. with fusible element, bimetal, memory shape or swelling material · CPC title

• A62C3/14

  in connection with doors, windows, ventilators, partitions, or shutters, e.g. automatic closing · CPC title

• A62C2/04

  Removing or cutting-off the supply of inflammable material · CPC title

• D06F37/42 Primary

  Safety arrangements, e.g. for stopping rotation of the receptacle upon opening of the casing door · CPC title