US2373282A - Door mechanism - Google Patents

Description

J. E. WOLF DOOR MECHANISM April 1-0, 1945.,

Filed July 27, 1943 2 Sheets-Sheet 2 IN V EN TOI-T.

Patented Apr. 10, 19.45

,l UNITED STATES PATENT orrlcs DOOR MECHANISM John E. Wolf, Dormont, Pa., assignor to Loftus Engineering Corporation, a corporation ofv Maryland Application July 27, i943, serial No. 496,301

(ol. 11o- 176) 7 Claims.

This invention relates to doors, particularly, though not exclusively, to sliding doors of the type found on certain industrial furnaces, such as car-bottom furnacesused in the annealing of metal castings, or other material to be heat treated.

The charge-supporting hearth of the -conven tional car-bottom furnace is formed by4 the refractory floor of a car that is adapted to travel on rails through the furnace doorway, between service position within the furnace and loading y and unloading position. without the furnace.

When the furnace is in operation the door engages at its .upper edge a sand seal included in the furnace structure above the furnacedoorway; at its lower edge the door engages a sand seal embodied in the car structure; and at the two sides of the doorway .the door bears upon a cheek plate mounted on the front wall of the furnace and extending across the top and down the two sides of the doorway. The door is movand of course it is desirable that the door, when in closed position, shall be hermetically tight upon the doorway. When the door is closed and opened able vertically between open and closed positions,

no diculty is encountered in establishing and interrupting the engagement of the door with the said seals, but the same does not hold true for the engagement of the door with the cheek plate. Under the effects of the wear and heat to which the door is in service exposed, it is difllcult, if not impossible, to maintain a snug sliding engagement of the edges-of the door upon the cheek plate, and for this reason furnace builders have tried various devices for clamping the door to the cheek plate. 'I'he clamping devices hitherto in use are manually released when it is desired 'to open the door, and manually locked again when the door is closed.

The door clamping mechanism of myvinvention operates automatically. When the door is lowered into closed position the mechanism locks itself, clamping the door with equalized pressure to the engaged areas of the cheek plate. Alternately, when the doorvv is raised, the mechanism moves automatically into release position. It is to be understood that the capacity of the mechanism to equalize the pressure of engagement of the doorv over the entire engaged area of the cheek plate is a feature of notable value.

In the accompanying drawings Fig. I is a fragmentary view in front elevation of a furnace door equipped with a clamping mechanism embodying the invention;

Fig. II is a vertical sectional view of the same on the plane II-II of Fig. I:

And Fig. III is a sectional view, on the `same plane as Fig. II, showing the furnace door fragposition,'Fig. II, and open position, Fig. III. The

means for opening and closing the door form no part of the present invention, and accordingly are not shown in the drawings. Extending along the upper edge of the door is a member 4 that is provided with a blade portion 5 which, when the door is lowered from open to closed position, em-

beds itself in usual way in a sand seal 6 carried by the front wall of the furnace, while the lower edge of the door carries two blades l that lodge in a sand `seal 8 provided in known way in the body of the car, which is fragmentarily indicated at 9. As thus arranged the door is intended to provide a substantially hermetic closure for the doorway of the furnace, but, as above mentioned,

under the conditions of service'the door normally does not seat tightly against'the cheek-plate. `The means of this invention for seating the door tightly in closed position in the doorway,

that is, upon the cheek-plate 2 in this case. comprise two sets of cam members a,l b and a, b. The two sets of cam members are spaced'apart horizontally, and the two cam members a and b in each set are aligned and spaced apart vertically. Means cooperate with said cam members,

lwhen the door is closed, to secure the door in tightly seated position of closure, and such means include an arm I0 vfor each c'am member. The

arms I0 are pivotally mounted on a rigid supporting structure. The supporting structure may conveniently consist, as herein shown, in the steel buckstays- I2 of the furnace framework. The

buckstays support bearing blocks I3 in 'which Y shafts Ily are journaled. The distal ends of the arms Ill are adapted to be engaged by their associate cam'members, and preferablythe engagement is anti-frictio'nal, rollers I4 being mounted in the arms for this purpose. In Figs.

scribed, the wedging action of the cam members i a, b upon theiarms is effective to press the door into tightly seated position against the vcheekplate 2. The door-seating cooperation between A the cam members` a, b and arms I is progressive as the descending door approaches its lowermost or closed position, and as he blades 5 and 1 enter the sand in the sand seals. By virtue of such feature the effect of the sand in resisting the slight but essential movement of the door towards the cheek-plate is minimized, and of substantially less eifect than it would be if thefdoor were fully closed and the blades fully embedded in the sand before the door-seating pressure was applied. When the door is raised into open position, the cam members move upwardly from engagement with the roller-equipped arms I0, and

it will be understood. that in neither the opening nor the closing of the door is there need for any manipulation of the door-seating or `clamping mechanism. The operation is automatic.

The means for limiting the outward rotation of the arms I0, under the effect ofthe cam members on the door descending into closed position, comprise arms I5 severally secured to the shafts Il. While each arm I5is spaced from the arm I0 on the shaft to which both arms are secured, the two arms are in mechanical eilect integral, and extend angularly to each other, as is shown to best advantage in Figs. II and III. Each pair of arms I5, thus organized, comprises in effect a bell-crank lever. The two arms I5 of the pair of levers in each vertically aligned set are pivotally interconnected by a tension rod I6, whose length is adjustable by means of a turnbuckle I1. Manifestly, when the door is loweredinto closed position, the 'pressure exerted by the upper bell-crank lever of each pair or set is trans.- mitted to the 'rod I5, and so is the pressure of the lower cam member on the arm I0 of the lower bell-crank lever. Thus, the pressure on the cam members a, b on the arms IIli of the two levers in each vertically aligned pair of levers is equalized. and the door is caused to bear with uniform pressure on all'of the area of contact of the door with the cheek-plate 2. y

The tension rods I6 also serve to limit the outward turning (a counterclockwise turning as seen in Figs. II and III) of the bell-crank levers I,' I5 under the effect of the cam members a, b

when the door is lowered into closed position. It will be nosfed that the arm I0 of the lower bellcrank lever extends downwardly fromthe axis II on which it turns, while the arm Ill of the companion upper lever extends upwardly. When length of each rod, aords adjustment of the outer limit of swing of the arms I0.

When the door is fully raised, the mechanism remains in such position as to cooperate with the cam members a, .b when the door is again lowered. The means for holding the disengaged mechanism in such position comprise brackets I8 welded to the buckstays I2 adjacent to which the rods I6 are located, and a spring I9 on each rod between the -turnbuckle and the bracket I8 through which the rod extends; cf. Figs. I and III. As the door is lowered, the two lower cam members b on the door engage and swing the arms II! of the upper levers outward beyond the normal limit vof their movement, there beingv hat Athat time no restraint against the rise of the rods I6 and the free turning of the lower arms III. scending door thus lengage and pass downwardly from engagement withthe upper bell-crank levers, and presently enter engagement with the lower bell-crank levers, at which time the upper cam members a on the doorseverally engage the rollers I4 of the upper levers. All of the levers are vnow engaged by cam members, andnone of the levers can swing outward beyond the limit described, the rod I6"tying the two levers of each pair or set together, so that one lever in a set cannot move without the other. Thus, as the door reaches closed position, the rollers I4 on the upper and lower levers provide fixed abut ments against which the cam members bear with wedging effect, and so press ltheedoor into tightly seated position against the cheek-plate 2.

Within the terms of the .appended claims various modifications are permissible. It will be understood that in the claims the terms upward and outward are intended to define the arrangement of the cam surfaces of the members a and b for a door that is raised into open position. If the door be one which is lowered into open position, the cam surfaces will extend outthe door is closing and both levers are subject to the action of the cam members, the rod I6 restrains or limits the outward` turning of the bellcrank levers, with the consequence that the cam members wedge against the rollers I4 and press the door into tightly seated position against the cheek-plates 2. The turnbuckle Il in each 'of the bipartite rods IB of the two sets of levers, providing for the adjustment of the effective ward and downward with respect to the plane of the'door, while if the door opens sidewise, the cam surfaces will extend outward and laterally of the door. 'I'he quoted words will be under stood rto embrace 4these variations. In the same manner, the words clockwise and counterclockwise, are intended as words of relationship and not limitation.

I claim as my invention: l

l. A furnace including a doorway and a furnace door movable substantially in the plane of the door between open and closed positions, two cam members secured to the door in spaced-apart relation in the direction of door movement, said cam members including cam surfaces which slope toward the plane of the door in the direction of door movement towards closed position, a supporting structure, two members pivoted to saidsupporting structure in spaced-apart relation in the direction of door movement, with the space substantially equal to the space between said cam members, said pivoted members severally including cam-engaging portions extending laterally from the axes of their pivots and adapted to rotate on their pivots when, as the .door moves into closed position, such portions are engaged by said cam surfaces, and means articulated to said pivoted members at points spaced laterally from the axes of the pivots and interconnecting the pivoted members to limit their rotation under the action of said cam surfaces, with the eiect that when the door reaches The lower cam members on the declosed position, it is clamped with equalized pressure.

2. The structure of claim 1, said last means comprising a tension member of variable xed length. I

3. 'I'he structure of claim 1, said pivoted members comprising bell-crank levers, substantially as described.

4. The structure of claim 1, said pivoted members comprising bell-crank levers, and said interconnecting means comprising a tension rod of variable xed length.

5. The structure of claim 1, said organization of cam members, pivoted mem-bers and' interconnecting means being `provided in two sets that arespaced apart transversely of the direction of door movement. A

6. A furnace including a. doorway and a furnace movable substantially in the plane of the door between open and closed positions, two cam members secured to the door in spacedapart relation in the direction of door movement, said cam members including cam surfaces which slope toward the plane of the door in the direc- .tion of door movement toward closed position, a

supporting structure, two members pivoted to said supporting structure in spaced-apart relation in the direction of door movement, with the space substantially equal to the space between said .cam members, said pivoted members severally including cam-engaging portions extending from their pivots one in opposite direction relauvelyfto the other. said pivoted members. beingrotatable in opposite directions on their pivots when, as the door moves into closed position, said portions are engaged by said cam surfaces, and means articulated to said pivoted members at points spaced from the axes lof the pivots and interconnecting the pivoted members tolimit their rotation under the eiect of said cam surfaces as the door closes.

7. A furnace including a doorway and a furnace door movable vertically between open and closed positions, two cam members secured to the doors in vertically spaced-apart relation, said cam members including surfaces that slope downward toward the plane in which the door is movable, -a supporting structure, two members pivoted to said supporting structure in vertically. spaced-apart relation, with the Space substantially equal rto the space between said cam members, said pivoted members. severally including cam-engaging portions extending one upward and one downward from their pivots said pivoted members being rotatable in opposite directions on their pivots when, as the door movesinto closed position, said portions are engaged by said cam surfaces, and means articulatedto said piv- 4 oted members at points spaced from their pivots and interconnecting the pivotedimembers to limit their rotation under the effect of said cam surfaces as the door closes.

. l.lOl-IN E. WOLF.

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