US2878533A - Doors for box cars - Google Patents

Description

March 24, 1959 w. A. BEAUCHAMP DOORS FOR BOX CARS 6 Sheets-Sheet 1 Filed Jan. 13, 1958 wuvsurma. Mafia Q fieeucmwp March 24-, 1959 w. A- BEAUCHAMP DOORS FOR BOX CARS 6 Sheets-Sheet 2 Filed Jan. 13 1958 BY W K 0 March 24, 1959 w. A. BEAUCHAMP DOORS FOR BOX CARS Filed Jan. 13 1958 6 Sheets-Sheet 4 /N VEN TO/P'a- \A//L FEED Q BmucHaMP 5 (Laue,

March 24,1959 w. A. BEAUCHAMP 2,878,533

DOORS FOR BOX CARS 6 Sheets-Sheet 5 Filed Jan. 13 1958 March 24, 1959 w. A. BEAU'CHAMP DOORS FOR BOX CARS a Shets-Sheet 6 Filed Jan. 13 1958 Unite DOORS FOR BOX CARS Application January 13, 1958, Serial No. 708,440 12 Claims. (CI. -23) This invention relates" to doors for box cars having wide door openings and more particularly to the construction and arrangement of double doors therefor whereby such cars shall be transformed into all-purpose cars.

It is an object of this invention to provide double doors for box cars having Wide door openings wherein the doors shall be so constructed and related to the cars as to impart to them the capability of transporting grain and other bulk materials in addition to lumber and other large and bulky products, palletized commodities, packaged goods and the like.

A further object is to provide double doors of the character noted above wherein the indicated capability shall be imparted to the cars in such a manner as to completely eliminate the need for grain doors.

A further object is to provide pairs of doors for box cars having wide door openings in the side thereof wherein the doors shall be laterally movable and longitudinally slidable, grain-tight and securely locked so as to withstand the pressure of grain and otherlading'.

A further object is to provide pairs of doors of the character set forth immediately above wherein the doors shall be so associated as to function substantially as a unit to withstand the pressure of lading in the cars.

A further object is to provide pairs of doors for box cars having wide door openings in the side thereof wherein the doors shall be laterally movable and longitudinally slidable and securely locked to each other and to the side Walls of the cars so as to become in effect parts of the side walls.

A further object is to provide pairs of doors of the character set forth immediately above wherein one of the doors of each pair can be opened and closed while the other door remains an integral part of the car side so as to provide box cars having narrower door openings adapted to be closed by single doors.

A further object is to provide pairs of doors for box cars having wide door openings in the side thereof wherein the doors shall be laterally movable and longitudinally slidable and securely locked to each other and to the side walls of the cars and one of the doors of each pair cannot be properly closed and locked until the other door is properly locked.

A further object is to provide pairs of doors for box cars having wide door openings in the side thereof wherein the doors shall be laterally movable and longitudinally slidable and one of the doors of each pair shall carry locking means adjacent to the front edge thereof which shall be so related to the front edge of the other door as to prevent lateral movement thereof into the door opening unless the one door is properly locked.

A further object is to provide pairs of doors for box cars having wide door openings in the side thereof wherein the doors shall be laterally movable and longitudinally slidable, grain-tight and securely locked so as to withstand the pressure of grain and other lading and one of the doors of each pair shall have a grain loading and inspection door.

Fatented Mar. 24, 1959 A further object is to provide pairs of doors for box cars having wide door openings in the side thereof wherein the doors shall be laterally movable and longitudinally slidable, grain-tight and securely locked so as to withstand the pressure of grain and other lading and one of the doors of each pair shall have a grain loading and inspection door and carry means permitting access to said latter door.

A further object is to provide pairs of doors for box cars having wide door openings in the side thereof wherein the doors shall be flush with the inside and outside of the side walls when seated in the door openings, laterally movable and longitudinally slidable, grain-tight and secu'rely locked so as to withstand the pressure of grain and other lading.

A further object is to provide pairs of doors for box cars having wide door openings in the side thereof wherein the doors shall be laterally movable and longitudinally slidable and carry mechanism for imparting lateral movement to them into and out of the door openings and one of the doors of each pair shall carry a locking device automatically operable by its mechanism for projecting the locking device into locking engagement with the other door as the one door moves laterally into the door opening and for retracting the locking device from the other door as the one door moves out of the door opening.

A further object is to provide pairs of doors for box cars having Wide door openings in the side thereof Wherein the doors shall be so constructed as to minimize damage to lading.

A further object is to provide pairs of doors for box cars having wide door openings in the side thereof wherein the doors shall be so constructed as to eliminate the dunnage required for the door openings of the present box cars. I

Other objects of the invention will become clear as the description thereof proceeds.

In the drawings forming part of this specification:

Fig. l is a side elevation of a railway box car erubodying the instant invention.

Fig. 2 is a view similar to Fig. 1 showing the main door of the instant invention in open position.

Fig. 3 is a horizontal section taken on line 3-3 of Fig. 1.

Fig. 4 is a view similar to Fig. 3 showing the main door in section in an intermediate position as it moves laterally out of the door opening and in dot and dash lines in its final position after it has completed its lateral movement out of the door opening.

Fig. 5 is a horizontal section taken on line 5'5 of Fig. 2.

Fig. 6 is a vertical section taken on line 6-6 of Fig. 1'.

Fig. 7 is a vertical section taken on line '7''7 of Fig. '2.

Fig. 8 is a fragmentary elevation of one of the side walls of the box car showing the lower portion of the doors of the instant invention on an enlarged scale.

Fig. 9 is a fragmentary elevation of a side Wall of the box car showing the upper portion of the auxiliary door of the instant invention and the grain loading and access door provided therein.

Fig. 10 is a horizontal section taken on line 10-40 of Fig. 9.

F Fig. 11 is a horizontal section taken on line 1111 of Fig. 12 is an enlarged fragmentary elevation showing the lower portion of the right-hand supporting structure for the auxiliary door.

Fig. 13 is a horizontal section'taken'on line 13-13 of Fig. 12.

Fig. 14 is a view similar to Fig. 13 showing'the door in open position.

Fig. 15 is a vertical section taken online 1515 of Fig. 8.

p Fig. 16 is a horizontal section taken on line 1616 of Fig. 8 this section being shown in two parts to permit an increase in the scale of this view.

Referring to the drawings which illustrate a preferred embodiment of the invention the numeral 10 designates a box car provided with a wide door opening 11 requiring two .doors to close it. In the embodiment of the invention illustrated, this door opening is 16 ft. in width, it being understood, however, that the width of the door opening may be greater or less than that illustrated and requiring double or pairs of doors to close the door opening. The door opening 11 according to the instant invention is closed by a pair of doors 12 'and 13. The door 12 is referred to as the main door and the door 13 as the auxiliary door. As shown more clearly in Figs. 3 to 7, inclusive, the main and auxiliary doors when in closed position lie flush with the inside and outside of the side wall 14 of the car.

The main door 12 embodies an outer metallic panel 15, the vertical margins of which are flanged inwardly as indicated at 16 and 17. The panel is reinforced by means of marginal substantially hat-shaped vertical reinforcing members 18 and 19 and similar horizontal reinforcing members 20 and 21. Additional reinforcement for the upper margin of the main door is provided by means of a horizontally extending angle member 22 whose vertical leg 23 is secured to the panel 15 and hatshaped member 20 and whose horizontal leg 24 extends inwardly so as to project when the main door is closed into a channel formation 25 formed in a door header 26. The latter is provided with an upstanding flange 27 which is secured to the depending leg 28 of the side plate 29 of the car. A reinforcing plate 30 connects the upstanding leg 31 of the side plate with the header 26 in the door opening.

The lower margin of the panel is also reinforced by means of an angle member 32 having an upstanding leg 33 secured to the lower horizontal hat-shaped member 21 and the metallic panel and an inwardly extending flange 34. Vertical nailing timbers 35 and 36 are secured in any desired manner to the front vertical margin of the main door and similar timbers 37 and 38 are secured in any desired manner to the rear vertical margin of the main door. Nailing timbers 39 and 40 are also secured as desired to the upper and lower horizontal margins of the door. These timbers serve as means to which an inner wooden lining 41 formed preferably of tongue and groove boards as shown in Fig. 6 of the drawings is nailed. The lining 41 constitutes the inner face of the door and is so disposed that when the door is closed it lies flush with the inner lining 42 of the car.

The main door is supported upon a track 43 for lateral movement into and out of the door opening and for movement along the track longitudinally of the car by means of roller carriages 44 and 45. The track 43 is supported upon the car below the door opening by means of a plurality of brackets 46.

To provide for lateral movement of the main door into and out of the door opening pipes 47 and 48 are rotatably mounted partly within recesses 49 and 50 provided in the door panel 15 by means of upper brackets 51 and 52 and lower brackets 53 and 54 secured to the door. Upper and lower cranks 55 and 56 are secured to the ends of pipe 47 and similar cranks 57 and 58 are secured to the upper and lower ends of the pipe 48. The lower cranks embody vertically adjustable spindles, one of which is shown at 59, supported for rotation within the roller carriages as more clearly illustrated in Fig. 12 of the drawings. The upper cranks 56 and 57 embody spindles, one'of which is shown at 60. These spindles extend upwardly into a retaining and guiding member 61 secured to the depending leg 28 of the side plate and serve to retain and guide the door upon the car.

Levers 62 and 63 are pivotally secured to the pipes 47 and 48 and serve to impart lateral movement to the main door into and out of the door opening. To complete such movement into the door opening and initiate such movement out of the door opening mechanism indicated generally by the reference character 64 is mounted upon the lower portion of the door between the pipes 47 and 48. The structure of this mechanism, its mode of operation and the manner in which it operates upon the ends of the levers 62 and 63 for the purpose indicated above is more fully described in applicants Patent No. 2,658,243, granted November 10, 1953, incorporated herein by reference.

One of the elements of the mechanism 64 is a follower 65 which moves laterally toward and away from the door 12 as the latter moves into and out of the door opening. The follower 65 is connected with a link 66 by means of a pin and slot connection 67. The link 66 is pivotally mounted upon the door 12 by means of a pin 68 carried by the door and is pivotally connected to a locking bolt 69 by a pin 70. By means of this structure the locking bolt 69 is projected into locking position as the follower 65 moves toward the door upon actuation of the mechanism 64 and is retracted from locking position as the follower 65 moves away from the door. In such movements the locking bar 69 is guided at the front margin of the door by means of a member 71 disposed within a recess in the door.

Similarly the follower 65 is pivotally connected by means of a pin 72 to a bell crank 73 pivotally supported upon the door by means of a pin 74. The lower arm of the bell crank 73 is pivotally connected by means of a pin 75 to a vertically disposed locking member 76 slidably mounted upon the lower portion of the door. From this construction it will be apparent that when the follower 65 moves laterally away from the door the locking member 76 will be moved upwardly out of engagement with a keeper 77 secured to the car below the door opening and when the follower 65 moves laterally toward the door the locking member 76 will be projected into engagement with the keeper 77 so as to lock the lower portion of the door to the car.

Except as described below the construction of the auxiliary door 13 is similar to the construction of main door 12. However, the front margin of the auxiliary door is additionally reinforced by an inwardly opening channel member 78 whose web 79 is secured to the front hat-shaped reinforcing member and door panel. The legs 80 and 81 of the channel reinforcing member 78 are flanged in opposite directions as indicated at 82 and 83. The inner open end of the channel member 78 is preferably closed by means of a plate member 84 which may be welded to the channel member 78.

Also the auxiliary door 13 is provided with a grain and access door 85 in the upper portion thereof. As shown this door is hinged at its lower edge as indicated at 86 and 87 so as to swing downwardly when it is desired to load grain into the car. When closed the grain door 85 is locked by means of a lever 88 swingably carried by the door and engageable with a slot provided in the outwardly extending horizontal leg 89 of a weather angle 90 secured to the auxiliary door above the opening which is covered by the grain door. To permit ready access to the grain and access door 85 the auxiliary door is provided with steps 91 and a handhold 92.

Furthermore while the auxiliary door retains the locking mechanism including the locking member 76 the locking bolt 69 and its associated mechanism are omitted from the auxiliary door.

In addition to its door reinforcing function the inwardly opening channel member 78 carries a locking device 93 by means of which the front margin of the auxiliary door is locked above and below the door opening to the side plate 29 and the side sill 94 of the car. The locking device 93 which is disposed within the channelshaped member 78 embodies upper and lower locking bolts 95 and 96 which at their adjacent ends are pivotally connected as indicated at 97 and 98 to a rocker arm 99 pivotally mounted intermediate its ends upon a pin 100 carried by a bracket 101 secured within the channelshaped member 78. In this manner the locking bolts 95 and 96 are adapted to be moved in opposite directions for projection into locking engagement with the side plate and side sill and for movement therefrom to unlocking position. In such movement the locking bolt 95 is guided by a member 102 and the locking bolt 96 is guided by a member 103 preferably in the form of a casting.

To impart projecting and retracting movements to the locking bolts a lever 104 is utilized. This member is pivotally supported upon the bracket 103 as indicated at 105 and is pivotally connected as shown at 106' to the lower locking bolt 96. The lever 104 is adapted to lie substantially within the channel-shaped member 78 when the locking bolts are in projected position and for this purpose moves through an opening 107 formed in the leg 81 of the channel-shaped member which lies adjacent to the front edge of the main door when the doors are closed. To retract the locking bolts 95 and 96 the lever 104 is swung downwardly as shown in the dash and dot position in Fig. 11 of the drawings. In this position the lever 104 lies in the path of lateral movement of the main door and prevent seating thereof within the door opening. Consequently before the main door can be properly closed the lever 104 must be swung into the channel-shaped member 78 thereby insuring proper locking of the front margin of the auxiliary door. In the closed position of the main and auxiliary doors the front edge of the former lies in the path of swinging movement of the lever 104 and thereby prevents such movement and accidental retraction of the locking bolts and the unlocking of the front margin of the auxiliary door.

In order to tie together the front margins of the main and auxiliary doors when they are in closed position a keeper 108 is secured to the leg 81 of the channelshaped member 78 within said member. This keeper is adapted to be engaged by the locking bolt 69 through an opening 109 provided in the leg 81. As shown in Fig. 16 of the drawings the outer leg 110 of the keeper is sloped outwardly and is adapted to cooperate with a similarly sloping face 111 of the locking bolt 69.

' to swing to vertical position.

The doors are shown in closed position in full lines inFig. 3 of the drawings. In this position the rear margins of the doors are overlapped by and retained against movement out of the door opening by flanges 112 and 113 carried by the side wall 14 of the car. Additional securement of the main and auxiliary doors in closed position is obtained by the engagement between the locking members 76 on the doors and the keepers 77 fastened to the car below the door opening. Securement of the front margin of the auxiliary door is also obtained by means of the locking device 93 seated within the channelshaped member 78. As shown more clearly in Fig. 16 of the drawings when the doors are closed the main door 12 overlaps the flange 83 formed on the channelshaped reinforcing member 78 which is secured to the front margin of the auxiliary door. This relationship between the front margins of the main and auxiliary doors plus the locking engagement between the locking bolt 69 on the main door and the keeper 108 provided on the auxiliary door serve to tie together the front margins of the doors.

In view of the relationship between these margins it is necessary to first open the main door when it is desired to gain access to the car. To accomplish this the mechanism 64 is actuated so as to slide the follower 65 of this' mechanism laterally away from the door. This movement of the fol-lower imparts movement to the ends of the levers 62 and 63 and resulting rotation to the pipes 47 and 48 which through the cranks at their u per and lower ends impart iniial lateral movement of the main door out of the door opening. Simultaneously the outward movement of the follower 65 retracts the locking bolt 69 and the locking member 76 from their respective engagement with the keeper 108 and the keeper 77 so as to release the front and lower margins of the door for continued movement laterally out of the door opening. At this time the levers 62 and 63 are disengaged from the follower 65 and the lever 63 is permitted The lever 62 is then swung toward the left whereupon the front margin of the door is moved laterally out of the door opening and the door assumes the position indicated by the dot and dash lines in Fig. 3 of the drawings. The main door is then moved forwardly so as to effect disengagement of its rear r'nargin from the flange 113. When this disengagement has occurred the lever 63 is raised and swung toward the right thereby moving the rear margin of the door laterally out of the door opening so that the door assumes the position shown in dot and dash lines in Fig. 4 of the drawings.

The main door can then be moved toward the right longitudinally of the car upon the roller carriages 44 and 45 to open position. The auxiliary door can then be opened. To do this the lever 104 of the locking device 93 which is secured to the front margin of the auxiliary door is swung downwardly so that the locking bolts and 96 are retracted from their keepers. Thereupon the mechanism 64 and levers 62 and 63 are actuated in the manner hereinabove described in connection with the main door having in mind that it is the auxiliary door which is being opened. This places the door laterally outwardly of the car side 14 so that it can be moved longitudinally of the car toward the left to open position. The side door opening is thereby exposed so that the loading of lumber or other large and bulky materials may readily be loaded into the car.

To close the door opening the auxiliary door is first moved to closed position. To accomplish this it is moved along the track upon the roller carriages 44 and 45 until the outer end of the crank 50 strikes the angle stop member 114 which is secured to the side sill structure 94. The relationship between these parts is illustrated in Fig. 14 of the drawings. At this time the rear edge of the auxiliary door has passed forwardly of the flange 112. The lever 62 is then raised and swung toward the right thereby shifting the rear margin of the auxiliary door laterally into the door opening. When this has occurred the lever 63 is raised and swung toward the left forcing the front margin of the door into the door opening. During the operation of the lever 63 the crank 53 rotates against the angle stop member 114 and imparts a rearward movement to the door so that the rear margin thereof moves behind the flange 112. The levers 62 and 63 are then re-engaged with the follower 65 and the mechanism 64 is actuated in order to complete the lateral movement of the door into the door opening. The actuation of this mechanism'automatically projects the locking member 76 into engagement with the keeper 77 so as to lock the lower middle portion of the door to the side structure. The front margin of the door is then locked to the car by swinging the lever 104 upwardly so as to project the locking bolts 95 and 96 into engagement with their keepers.

The main door is then moved longitudinally along the side wall 14 and laterally into the door opening in the manner described in connection with the auxiliary door. l-Ioweve'r, in the event that the front margin of the auxiliary door is not properly locked the lever 104 will project into the path of lateral movement of the main door and prevent its proper seating in the door opening. The lever thereby serves as a tell-tale to indicate whether the front margin of the auxiliary door is properly locked or not. Assuming that it is properly locked the main door will move laterally into the door opening so that the doors will assume the position shown in full lines in Fig. 3 of the drawings. At this time the inside of the doors is flush with the inside lining of the car. During the movement of the main door laterally into the door opening by the actuation of the mechanism 64 the locking member 76 is automatically projected into locking engagement with its keeper 77 and the locking bolt 69 is automatically projected into locking engagement with the keeper 108 provided on the front margin of the auxiliary door. Also the front margin of the main door lies in overlapping relationship with the flange 83 of the chanml shaped member 78. The main and auxiliary doors are thus securely locked to the side wall and to each other so that they can successfully resist the outward pressure of lading within the car.

As shown in Fig. 6 of the drawings the cranks 55 and 57 at the upper ends of the pipes 47 and 48 move through recesses 115 provided in the depending leg of the side plate 29 and into castings 116 which cover the recesses and reinforce the side plates.

With reference to Figs. 13 and 14 it will be seen that the cranks 56 and 58 on the lower ends of the pipes 47 and 48 move relatively into castings 117 which are secured in recesses provided in the lower portions of the door as the door moves laterally out of the door.

After the doors have been closed and locked the car may be loaded with grain to the extent required by the kind of grain. To accomplish this the grain door 85 is unlocked and permitted to swing downwardly about the hinges 86 and 87. The grain loading spout is inserted in the grain door opening and the car is loaded. The grain door is then swung upwardly and locked. It will be observed that in view of the instant invention the need for additional grain doors is obviated.

Moreover, because of the smooth interior which is obtained by the doors of the instant invention dunnage heretofore required for the door openings covered by the customary doors is eliminated. Also the damage which has heretofore occurred to commodities shipped in bags, cartons and other packages because of the offset relationship between the inner face of the doors and the inner lining of the car is prevented. Yet when a single door car is required the instant invention serves equally as well. In this situation the auxiliary door remains closed, thereby reducing the size of the door opening. The auxiliary door thus becomes in effect an integral part of the side wall of the car. The main door then is the only door that is operated to open and close the door opening. It will be apparent that numerous changes and modifications in the details of the invention will be clear to those skilled in the art. It is intended, therefore, that all such modifications and changes be comprehended within this invention which is to be limited only by the scope of the claims appended hereto.

1 claim:

1. In a railway box car a side wall provided with a wide door opening, main and auxiliary laterally movable doors for closing the door opening, said doors when closed being seated in the door opening flush with the inside and outside of said side wall, a track on said car below the door opening, means mounting said doors upon said track for movement therealong in opposite directions longitudinally of the car, mechanism carried by said doors and operable to impart lateral movement thereto into and out of the door opening, pairs of fixed flanges extending vertically along both sides of the door opening substantially in the inner and outer planes of said side wall, the rear margins of said doors lying between said pairs of fixed flanges and the front margin of said main door overlapping the front margin of said auxiliary door when said doors are closed, locking means carried by the front margin of said auxiliary door for locking said margin to said side wall above, and below the door opening when said auxiliary door is closed and locking means carried by said main door, said latter locking means being projected into engagement with the front margin of said auxiliary door when said doors are closed. e

2. In a railway box car a side Wall provided with a wide door opening, main and auxiliary laterally movable doors for closing the door opening, said doors when closed being seated in the door opening flush with the inside and outside of said side wall, a track on said car below the door opening, means mounting said doors upon said track for movement therealong in opposite directions longitudinally of the car, mechanism carried by said doors and operable to impart lateral movement thereto into and out of the door opening, the front margin of said main door overlapping the front margin of said auxiliary door when said doors are closed, means securing the rear margins of said doors to said side wall for preventing movement of said margins out of the door opening when said doors are closed, locking means carried by the front margin of said auxiliary door for locking said margin to said side wall above and below the door opening when said auxiliary door is closed, and locking means carried by said main door, said latter locking means being projected into locking engagement with the front margin of said auxiliary door when said doors are closed.

3. The combination as defined in claim 2 wherein said latter locking means is operatively connected with said mechanism carried by said main door and is automatically projected into or retracted from locking engagement with said auxiliary door when said auxiliary door is closed by the operation of said latter mechanism to move said main door into or out of the door opening.

4. The combination as defined in claim 2 wherein said auxiliary door is provided with a grain loading and inspection door in the upper portion thereof whereby said car is capable of carrying grain while eliminating the need for grain doors.

5. The combination as defined in claim 2 wherein said auxiliary door is provided with a grain loading and inspection door in the upper portion thereof and carries means providing access to said latter door.

6. In a railway box car a side wall provided with a wide door opening, main and auxiliary laterally movable doors for closing the door opening, said doors when closed being seated in the door opening flush with the inside and outside of said side wall, a track on said car below the door opening, means mounting said doors upon said track for movement therealong in opposite directions longitudinally of the car, mechanism carried by said doors and operable to impart lateral movement thereto into and out of the door opening, means securing the rear margins of said doors to said side wall for preventing movement of said margins out of the door opening when said doors are closed, locking means carried by the front margin of said auxiliary door for locking said margin to said side wall above and below the door opening when said auxiliary door is closed, and locking means mounted upon said main door for locking the front margin thereof against movement out of the door opening when said main door is closed.

7. The combination as defined in claim 6 wherein said locking means for the front margin of said auxiliary door embodies vertically slidable locking bolts and a pivotally mounted actuating lever swingable in a plane parallel to said auxiliary door, said lever projecting beyond the front margin of said auxiliary door and into the path of lateral movement of said main door when said auxiliary door is closed but not locked.

8. The combination as defined in claim 6 wherein said locking means for the front margin of said auxiliary door embodies vertically slidable locking bolts and a pivotally mounted actuating lever swingable in a plane parallel to said auxiliary door, said main door when closed lying in the path of swinging movement of said lever when said auxiliary door is locked and preventing swinging movement of said lever.

9. The combination as defined in claim 6 wherein said locking means for the front margin of said auxiliary door embodies vertically slidable locking bolts and a pivotally mounted actuating lever swingable in a plane parallel to said auxiliary door, said ever projecting beyond the front margin of said auxiliary door and into the path of lateral movement of said main door when said auxiliary door is closed but not locked, said main door when closed lying in the path of swinging movement of said lever when said auxiliary door is locked and preventing swinging movement of said lever.

10. The combination as defined in claim 6 wherein said locking means for the front margin of said auxiliary door embodies vertically slidable locking bolts lying within said auxiliary door and a pivotally mounted actuating lever swingable vertically in the plane of the door, said main door when closed lying in the path of swinging movement of said lever when said auxiliary door is locked and preventing swinging movement of said lever.

11. The combination as defined in claim 6 wherein the front margin of said auxiliary door includes a vertically extending substantially channel-shaped member and said locking means for the front margin of said auxiliary door embodies vertically slidable locking bolts lying in said channel-shaped member.

12. The combination as defined in claim 2 wherein the front margin of said auxiliary door includes a vertically extending substantially channel-shaped member, said locking means for the front margin of said auxiliary door embodies vertically slidable locking bolts lying within said channel-shaped member and said locking means on said main door is received within a keeper carried by and extending into said channel-shaped member when said latter locking means is projected into locking engagement with the front margin of said auxiliary door.

References Cited in the file of this patent UNITED STATES PATENTS

Images