US 3770306 A
A fire door lock assembly having a slidable latching bolt which is retained in longitudinal and transverse disposition with minimum surface contacts so as to reduce harmful affects of corrosion which may result from humid or other mildly corrosive environments. The structure employs a guide channel for the latching bolt together with a spherical guide ball which is utilized to control the transverse disposition of the bolt within the guide channel. Means are provided for controllably moving the latch from locking disposition to open disposition.
Description (OCR text may contain errors)
Nov. 6, 1973 United States Patent 1 1 Nystrom [5 FIRE DOOR LOCK ASSEMBLY 1,233,295 7/1917 Appleby.............................. 292 337  Inventor: James C Nystrom, 5225 Evanswood 2,223,765 12 1940 Komenak......................,..... 292 337 Ln., Minneapolis, Minn. 55436 June 15, 1972 Primary Examiner-Albert G. Craig, Jr. Attorney-Orrin M. Haugen  Filed:
Appl. No.: 263,144
ABSTRACT A fire door lock assembly having a slidable latching bolt which is retained in longitudinal and transverse osition with minimum surface contacts so as to reduce harmful affects of corrosion which may result from humid or other mildly corrosive environments. The structure employs'a guide channel for the latching d 76 ,1 31 3 3 6 I113 2 G 3% m n M .mm r
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FIRE DOOR LOCK ASSEMBLY BACKGROUND OF THE INVENTION The present invention relates generally to an improved fire door lock assembly, and more specifically to such a lock assembly which may be utilized in humid or other mildly corrosive environments without becoming susceptible or subject to frequent failure because of corrosion. The structure may be prepared from normal materials of construction, thus avoiding the requirement of expensive tooling operations or the like. The
improved fire door lock assembly of the present invention is capable of use for those various panels which are employed for fire purposes, including doors and windows, which are normally closed by force or influence of gravity. Because of the positive action and durability of the structure, it is compatible for use with those various systems which are only normally infrequently checked, however when required, are reliable and positive in their operation and function.
In the design of fire door lock and latching assemblies, it is normally anticipated that the fire panel closure assembly will be actuated only very infrequently, and primarily for purposes of testing the capability of the apparaus.
FIre panels may be either normally open or normally closed. If normally open, the panel frequently remains open until triggered by a condition responsive system indicating the presence of fire. If normally closed, the panel is provided with a closure device which applies moderate force against the panel to urge it in closed disposition. In either event, however, fire peanels must be easily re-opened in-order to permit persons who may otherwise be trapped to escape the closed area. In a normally open system, fusible links are utilized which, upon fusing, permit gravity closing of the fire panel. Alarm-actuated means or the like may' provide for closure of the panel upon an indication of fire. The force utilzied to accomplish the closing is either gravity alone or a spring biased device such as a torsion springorthe like. Consistent with the forces avialable, the system should provide for positive latched closing with minimal force being required for ,re-opening.
SUMMARY .OF THE INVENTION In accordance with the present invention, therefore, an improved fire door lock assembly is provided which utilizes a latching bolt maintained within a channel member and retained for slidable latching action. Resilient biasing means are provided for normally urging the.
latching bolt toward a locking disposition, with rotatable handle means being provided for controllably moving the latch from locking disposition to open disposition. The latching bolt is maintained in place by the channel member, and teh surface area of contact between the channel member and the bolt body is limited, and maintained in limited relationship by the presence of a spherical bearing member which fucntions as a mean between the bolt and the frame with reduced and minimal surface contact and hence reduced or minimal friction.
Therefore, it is a primary object of the present invention to provide an improved fire door lock and latch assembly which is capable of use in humid or other mildly corrosive environments, with the structure being designed to resist deleterious operational affects due to modest amounts of corrosion.
It is still a further object of the present invention to provide an improved fire door locking mechanism which provides positive action upon closing, but yet achieves positive closing with minimal forces being required. I
It is yet a further object of the present invention to provide an improved fire door lock assembly which is positive in its functioning, and yet permits manual control of the latching bolt when closed.
Other and further objects of the present invention will become apparent to those skilled in the art upon a study of the following specification, appended claims, and accompanying drawing.
BRIEF DESCRIPTION OF THE DRAWING FIG. 1 is a perspective view showing the improved fire door lock assembly of the present invention, and showing, in phantom, a door panel upon which the assembly is mounted, with a portion of the assembly being shown broken away;
FIG. 2 is a plan view of the mechanical features of the v assembly with the latching bolt being shown in extended disposition, with a portion of the frame being cut away to show the mechanism in greater detail, and with portions of the frame being shown in section;
FIG. 3 is a view similar to FIG. 2 with the latching bolt being shown in retracted disposition;
FIGS. 4 and 5 are horizontal sectional views taken along the line and inthe direction of the arrows 4-4 and 5-5 respectively of FIG-3, and illustrating the latching blot in retracted disposition; and
FIG. 6 is a top plan view of the structure shown in FIG. 1 with the latching bolt being shown in extended disposition.
DESCRIPTION OF THE PREFERRED EMBODIMENT In accordance with the preferred embodiment of the present invention, and as-illustrated in the drawings, the fire door lock assembly generally designated 10 includes a slidable latching bolt 1 l disposed within frame means for retaining the bolt along a predetermined longitudinal and transverse path. The frame means includes a front plate 12 and a rear generally U or channel shaped member 13 secured thereto by suitable means such as spot welding or the like. The latching bolt 11 has a forward bevelzone 15 which extends downwardly from the forward surface toward the rearward surface to permit actuation upon striking the striker plate of the mating stationary panel, shown in phantom in FIG. 1.
Resilient biasing means in the form of spring members l6 and 17 are utilized to normally urge the latching bolt toward the locking disposition. These spring members are held in place between the stationary plate 19 which is secured to member 13, and with the other ends of the springs being received n the recess areas 20 formed in the bolt 11.
A rotatable member is provided with handle means for controllably moving the latching bolt from locking disposition to open disposition, this including a generally cylindrical member 25 having an exposed forward face 2 and a rear abutment face 27, with the face 27 being interiorlydisposed and in surface-to-surface contact with the face of bolt 11. I-Iandle element 28 having the ends thereof received in recesses 29 and 30 of member 25 is provided to controllably move the latch from locking disposition to open disposition. Eccentrically disposed bolt engaging peg 31 is provided for actuating the bolt along the longitudinal path. Peg 31 is received within recess slot 32 formed in bolt 11, with the ends 33 and 34 being utilized as abutment surfaces to cause motion or movement of the bolt 1 1. As is illustrated in FIG. 5, a second slotted area 36 is formed in bolt 11 for accommodating the spherical bearing member 38 therewithin. Spherical bearing 38 is received within slot 36 and is arranged to make contact wlth the front surface of panel 12 and accordingly guides the bolt 11 in its transverse movement, and thereby limits the area of surface-to-surface contact between bolt 11 and panel 12. In this fashion, wih a limited area of contact being proved, the system is less susceptible to malfunctions due to continued presence within humid or other mildly corrosive environments or atmospheres.
While the system has been shown as being used on a door panel, it will be appreciated that window panels or the like may be equipped with the fire lock assembly, thus rendering the system useful in connection with a wide variety of panels. It will accordingly be appreciated that the term door is being employed in a broad comprehensive sense.
As materials of construction, conventional coldrolled steel may be employed for the components, with more highly durable materials being utilized, if desired. The system is susceptible for use in connection with these conventional materials of construction, and hence the unit is relatively inexpensive, and yet both durable an4 reliable.
I claim 1. In a fire door lock assembly:
a. a slidable latching bolt, frame means including a front panel and a channel member secured thereto 4 for retaining said slidable latching bolt along a pre determined longitudinal and transverse path between locking and open dispositions, said latching bolt having forward and rearward surfaces, with a latching bevel extending downwardly from said forward surface toward said rearward surface;
b. resilient biasing means for normally urging said latching bolt toward said locking disposition;
c. rotatable handle means for controllably moving said latch from locking disposition to open disposition and including a generally cylindrical member having an exposed forward face at one end and a disc-shape interior abutment face at the other end thereof, said abutment face engaging the forward surface of said latching bolt and having an eccentrically disposed bolt engaging peg extending therefrom, first slot means formed in said forward surface of said bolt for receiving said bolt engaging peg; and
d. second slot means formed along said forward bolt surface and generally beneath said latching bevel zone and arranged to receive a sherical bearing member therewithin, a spherical bearing disposed within said second slot and arranged to guide said bolt transversely within said channel member.
2. The fire door lock assembly as defined in claim 1 being particularly characterized in that said resilient biasing means include a pair of generally parallelly disposed compression spring members.
3. The fire door lock assembly as defined in claim 1 being particularly characterized in that said generally cylindrical member of said rotatable handle means is mounted for rotation within a bore formed in said front panel member.
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