Emergency latch for a hatch structure
United States Patent 3877173

Latching means is disclosed for inter-floor building hatch structures having a frame in which a door is hung to close by gravity, wherein the latching means operably engages a hinged lever of the hatch structure to hold the door open for inter-floor venting or access but which may be manually disengaged to permit the door to close, means also being incorporated to effect disengagement automatically in an emergency.

Application Number:
Publication Date:
Filing Date:
Primary Class:
International Classes:
A62C2/24; (IPC1-7): E05F15/20
Field of Search:
49/1-8,379 160
View Patent Images:
US Patent References:
3792556ROOF COVERING1974-02-19Anghinetti et al.
3777422SKYLIGHT AND SAFETY DEVICE1973-12-11Janssen
3557497N/A1971-01-26Schafer et al.
2983343Manual and automatic releasable lock1961-05-09Lyons

Primary Examiner:
Taylor, Dennis L.
Attorney, Agent or Firm:
Steward & Steward
What is claimed is

1. In a hatch structure comprising a frame and a door hung in said frame to close by gravity, operating means facilitating the manual movement of the door between open and closed positions relative to said frame and comprising a brace hinged to the frame, a track member mounted on said door, and slide means at the unhinged end of said brace confined for sliding movement in said track member with opening and closing of the door, the improvement which consists of latching means for coacting with said operating means to latch said brace in door-open position but releasable automatically upon occurrence of fire to release said brace and permit said door to close, said latching means comprising:

2. Latching means for a hatch structure as defined in claim 1, wherein said retaining means comprises a fusible metal link which fails on exposure to predetermined ambient temperature.

3. Latching means for a hatch structure as defined in claim 1, wherein said retaining means includes a pin and a member slidably supporting said pin, and remotely controlled actuator means for withdrawing said pin from said supporting member.

4. Latching means for a hatch structure as defined in claim 3, wherein said retaining means further includes a fusible metal link interconnecting said pin and said latching means.

5. Latching means for a hatch structure as defined in claim 1, which further includes compression spring means secured to said door so as to be engaged and compressed by said keeper in the final increment of slide travel toward full open position of the door.


Many fireproof building structures such as factories, warehouses, the holds of ships and the like employ ventilating or access hatches located in the flooring between different levels of the structure. The common arrangement is to build a hatch or access way into the flooring of the structure with the hatch door hung in a frame in such manner that the door will normally close of its own weight by gravity. To provide inter-floor access or ventilation, some means is employed to block the door in open position. However most fire regulations require that in case of fire developing within the building, provision must be made to have the hatch door close automatically to isolate one floor from the other. Means for automatically accomplishing this have been proposed, but in the arrangements used heretofore and means employed either complicates or interferes with desired manual operation of the hatch door for normal access or ventilation. Such manual operation of the door is desired so that it may be closed during periods when the inter-floor ventilation or access is not required.

It is accordingly a general purpose of devices of the present invention to provide hatch doors that can be latched in open position, wherein the latching means is automatically disengaged to close the door in case of fire, yet the door may be manually operated as desired to open and close it without being complicated or adversely affected by the automatic emergency-actuated provision.


The novel latching arrangement is characterized by the use of a movable catch member secured to the hatch door in position to cooperate with a keeper fastened to one end of a door hold-open arm or lever. This lever is hinged at one of its ends to the door frame, while the other end is slidably engaged in a track on the door. In normal operation the door may be manually pushed to open position, against the normal closing bias of its own weight by reason of the hinging arrangement, and upon arrival at open position the catch automatically engages the keeper to retain the door open. For normal closing of the door, the latch may be manually disengaged from its keeper and the door allowed to close. In case of the fire within the building, suitable sensor elements located either at the door or remotely are operated to disable the catch and allow the door to swing closed of its own weight.

The invention is described with reference to certain structures shown in the accompanying drawings. These exemplify presently preferred structural arrangements but it will be obvious that changes in such structures may be made within the scope of the inventive concept as defined by the appended claims.


FIG. 1 is a view in side elevation, partly in section, of a hatch structure incorporating the novel latching means, the door being shown in closed position relative to a hatch frame;

FIG. 2 is a fragmentary view in side elevation of the hatch structure with the door latched in open position;

FIG. 3 is a fragmentary front elevational view, partly in section, of the hatch with the door in open position;

FIG. 4 is a detailed view on an enlarged scale showing one form of suitable latch mechanism; and

FIG. 5 is a view in side elevation of the latch means seen in FIG. 4.

The hatch structure 10 seen in FIGS. 1-3 consists of a door 12 having hinges 14 connecting it to a frame 16. Door 12 is accordingly swingable from a closed position relative to the frame as seen in FIG. 1 to an elevated, open position as seen in FIGS. 2 and 3. The arrangement is such that the door normally is biased to closed position by its own weight. Compression spring counterbalances 18 are mounted on frame 16 at one or more points along or adjacent the hinge axis, and are pivotally connected by brackets 20 to the undersurface of the door in order to counteract most of the weight of the door and permit it to be moved easily by a man from closed to open position. These counterbalances, however, do not totally overcome the door weight so that there is still a closing bias on the door.

A brace or hold-open arm 22 is pivotally mounted at one side of frame 16 in spaced relation to the hinge axis to swing in a plane perpendicular to that of the hinge axis, and arm 22 serves to brace the door in open position. At its opposite end, arm 22 is constrained for sliding movement in a track 24 secured to the underface of door 12. Track 24 is formed with a longitudinal slot 26, and a rod 28 welded to the end of arm 22 is engaged in slot 26. An inward extension of rod 28 is bent to form an offset 30 which functions as a keeper member for a latch mechanism 32 which includes a catch 34. This catch is pivotally mounted on pin 36 of clevis 38 secured to the end of a reciprocable carrier member 40. A spring 42 is employed to bias catch 34 in clockwise direction, as viewed in FIG. 1, until the heel 43 of catch 34 strikes the hub of clevis 38. Latch mechanism 32 is bolted or welded to the underface of door 12 at a point such that catch 34 is disposed directly adjacent the inner end of slot 26 of slide 24. As keeper 30 is moved toward catch 34 when swinging door 12 from the closed position seen in FIG. 1 to the open position in FIG. 2, the keeper strikes the nose of catch 34 just short of the full open position of the door, causing catch 34 to pivot counterclockwise about clevis pin 36 against the bias of spring 42, thus allowing the catch to ride over and then engage keeper 30 as the door arrives at fully open position. Such engagement locks hold-open arm 22 so that it cannot slide back along slot 26. Accordingly door 12 is braced by arm 22 in open position. When it is desired to close the door manually, finger ring 44 of catch 34 provides a convenient handle for manually tripping the latch to allow the outer end of arm 22 to slide back along slot 26 as the door swings shut.

For reasons that will appear presently, it is desirable to incorporate a spring preload on door 12 urging it out of the fully open position of FIG. 2, in which position the plane of the door is virtually perpendicular to frame 16 to give maximum access through the hatchway. A compression spring 46 mounted on a bracket 48 in axial alignment with slot 26 at its inner end provides this preload. Spring 46 in normal extended position overlaps the inner end of slot 26 so that as rod 28 approaches the inner end of the slot on swinging door 12 to fully open position, spring 46 is contacted by the rod and is compressed and held in compression by engagement of keeper 30 in catch 34. Upon releasing catch 34, therefore, spring 46 initiates return sliding movement of the free end of arm 22 in slot 26. This produces a moment acting through track 24 initiating swinging of the door 12 off vertical dead center toward closed position. The preload also puts a load onto catch 34 through engagement of keeper 30 with the hooked undersurface of catch 34. This point of engagement is designed to impose a clockwise moment of rotation to catch 34 when the parts are disposed in the position seen in FIG. 2, to further ensure securing the catch.

With door 12 braced in open position by the arm and latch means, it is necessary to provide means whereby the latching mechanism will be automatically disengaged upon the occurrence of a fire within the building, or some other predetermined emergency event. Latch mechanism 32 provides for this, and particularly suitable constructions are described in detail in U.S. Pat. Nos. 3,516,198 and 3,601,437. For purposes of present illustration, a latch of the type disclosed in the first-named patent is shown in the accompanying drawings, and more particularly in FIGS. 4 and 5; but a latch of the type shown in the later patent is fully equivalent.

Referring to FIGS. 4 and 5, the latch construction is briefly described as follows.

A sheet metal frame 50 is bent into a rough S-shape, and a bearing sleeve 52 is welded or otherwise secured in the central vertical leg of the frame. Sleeve 52 receives the previously mentioned reciprocable carrier 40 to which clevis 38 is attached, carrier 40 being vertically reciprocable within limits in sleeve 52. Carrier 40 is normally retained in its lowermost position (in which the base of the clevis abuts the upper end of sleeve 52) by engagement between an L-shaped foot 54 secured to the lower end of carrier 40 and the shorter leg 56 of a lever 58. The lever is mounted on a pivot pin 60 supported in the lower end of frame 50. The longer leg 62 of lever 58 projects upwardly and is trapped in a socket member 64 forming part of a second lever 66. The later is similarly mounted on a pivot pin 68 carried by brackets 70 secured to the underside of the medial horizontal leg of frame 50. Socket member 64 is secured to the shorter leg 72 of this lever, while its longer leg 74 projects outwardly at one side of frame 50 where it is formed with a slight downward hook 76. A bracket 78 is welded to the upper vertical leg of frame 50 so as to project laterally from the frame, and is bent to form a leg 80 which is provided with an aperture 81 through which an emergency release pin 82 passes. A fusible metal link 84 is connected between release pin 82 and the hooked end 76 of lever 66, normally preventing the later from swinging downward about its pivot. As seen more particularly in FIG. 3, release pin 82 is connected to an actuator 86 which may be an electrically or mechanically actuated device mounted on the underside of door 12 adjacent the latch mechanism. A remotely located sensing element (not shown) is employed to trigger actuator 86 to withdraw pin 82 and disengage fusible link 84.

In the event of a fire within the building in which the hatch construction is employed, trigger lever 66 of the latching mechanism is released in either of two ways. If the ambient temperature adjacent the hatch is sufficiently high, fusible link 84 will melt to allow lever 66 to drop. Alternatively if the remote sensing element mentioned above causes actuator 86 to be operated, withdrawing release pin 82, again the trigger lever 66 will be free to swing downward. When this occurs, leg 62 of lever 58 is no longer constrained by engagement of socket member 64. Accordingly lever 58 is free to swing counterclockwise (as seen in FIG. 4) which raises short leg 56 and allows carrier 40 to rise in bearing sleeve 52. This upward force on carrier 40 is imparted through reaction of keeper 30 on catch 34, under the influence of the biasing preload of compression spring 46. Since the upward movement of carrier 40 is no longer restrained, catch 34 rises until its projecting heel 35 engages the terminal upper leg 51 of frame 50. Such engagement overcomes biasing spring 42 and causes catch 34 to rotate (clockwise in FIG. 5), releasing keeper 30. Arm 22 then becomes ineffective as a hold-open brace and door 12 starts to swing to closed position under the initiating bias of spring 46. Door 12 is then free to fall to closed position.

The particular internal design of the latching means described is not essential to the present invention, as other arrangements for mounting the carrier for catch 34 to permit disengagement or movement of the carrier will be obvious. In the above-mentioned U.S. Pat. No. 3,601,437, the carrier element is pivotally movable rather than slidably reciprocable, for example.