Underground mine personnel doors

#1. Field of the Invention

#This invention relates generally to underground mine personnel doors and, more specifically, to underground mine personnel doors formed from substantially noncombustible materials and that are constructed to withstand heat generated during an underground mine fire.

#2. State of the Art

#FIG. 1 is a back view of a mine door secured in a stopping in a mine passageway in accordance with the present invention;

#FIG. 2 is a front view of the mine door in accordance with the present invention;

#FIG. 3 is a back view of a door skin of the mine door in accordance with the present invention;

#FIG. 1 illustrates a preferred embodiment of a mine door 10 in accordance with the present invention installed in a wall 12 of masonry material (commonly referred to in the industry as a "stopping") that has been erected in an underground mine shaft or passageway 14. The mine door 10 is comprised of a frame 16 having two upright support members 18 and 20 and two cross-members 22 and 24 with the door skin or panel 26 hingedly mounted therein so that the door can swing open to allow personnel and equipment to pass or be passed through the doorway. The mine door 10 also includes one or more latching devices 28, depending on the size of the door, that latch and secure the door panel 26 to the door frame 16.

#As shown in FIG. 2, the door 10 includes one or more hinges 30 that mount the door panel 26 to the frame 17 and a door stop 32 comprised of an elongate member extending from the cross member 25 to prevent the door panel 26 from substantially sagging when the mine door 10 is exposed to intense heat, as may be the case in the event of an underground mine fire. In addition, the door frame 17 comprising cross members 29 and 31 may each have C-shaped cross-sections so that the stopping can fit therein and hold the door 11 in place (as later shown in FIGS. 4 and 7). FIG. 3 shows the back side of the door panel 26 comprising a substantially rectangular sheet 34 of material, preferably made of between 12 and 14 gage including cross-breaks 36 and 38 to add structural strength to the sheet 34. At a position inset from the outer perimeter 40 of the door panel 26, a plurality of structural support members 42, 44, 46, and 48 are attached to the sheet 34. The support members 42, 44, 46, and 48 may be comprised of steel tubing, preferably 1 inch.times.2 inch 14 gage tubing, welded to the sheet 34. The door panel 26 also includes a bore 50 cut therethrough for insertion of the latching device 28 and a seal member 52 around the perimeter 40 of the door panel 26. Of course, the seal member 52 may be comprised of one or more segments positioned end-to-end around the door perimeter 40.

#As shown in cross-section in FIG. 4, the latching device 28 is comprised of a first handle 54 attached to one end 55 of an L-shaped connecting member or interconnecting rod 56 that extends through the sheet 34 of the door panel 26. The interconnecting rod 56 is bent at approximately a 90 degree angle with the bent portion forming the latching member 58. It is also contemplated that the latch member 58 could be a separate piece from the interconnecting rod 56. Proximate to the bend 60 and depending from the interconnecting rod 56 is another handle 62 shown in dashed lines. The interconnecting rod 56 is secured to the sheet 34 by a door handle mount 64, comprised of a tubular member 66 having an internal bore 68 therethrough positioned over the bore 50 and attached to the inside of the sheet 34 as by welding. The interconnecting rod 56 extends through the tubular member 66 and is rotatable therein. An abutment member 70, such as a metal washer, is attached to the interconnecting rod 56 and abuts the tubular member 66. A locking sleeve 72 is attached to the interconnecting rod 56 by one or more set screws 74 and is positioned against the front side of the sheet 34. The interconnecting rod 56 can thus rotate relative to the door panel 26 but is longitudinally held relative thereto. In addition, the latch member 58 may be biased with a biasing member 59 such as a coiled spring with the biasing member 59 attached at one end to the door panel 26 and at the other end to the latch member 58 (see FIG. 1). Moreover, over rotation of the latch member 58 by the biasing member 59 can be prevented by providing abutment member 61 attached to the tubular member 66 and extending over the latch member 58 to prevent rotation thereof beyond a position engageable with the latch plate 76 (see FIG. 1). Similarly, a portion of the latch member 58, a portion of the handle 62, and/or a member attached to the interconnecting rod 56 proximate the bend 60 could be fitted into the tubular member 66 such that the tubular member 66 provides abutment surfaces therein and limits the range of rotation of the latch member 58.