RETRACTABLE LADDERS
United States Patent 3809181
A retractable ladder is disclosed which includes a flexible ladder having rungs spanning a pair of flexible lines, the upper ends of which are fastened to the interior of a generally rectangular box container whose lower wall swings open to release the ladder and permit it to fall so that it can be extended to full length. The upper wall of the box can be opened whereby the ladder can be returned to storage in the box by pulling it up through the box. The container is mounted on a frame which serves as a means by which the unit may be mounted at the side of a building, generally below a window. The unit includes a fixed ladder to facilitate crawling over the container and down to the flexible ladder which extends below it. The container is provided with a special latch operable from above which secures the lower wall of the container in place and so that the ladder will be contained until it is needed.
US Patent References:
Apparatus for picking up and lowering a pilot at sea
Major - May 1965 - 3183998
Apparatus for picking up and lowering a pilot at sea
Major - May 1965 - 3183998
Inventors:
Staranick, Steve (Orange, CA)
Garrison, Jerome R. (Stanton, CA)
Garrison, Jerome R. (Stanton, CA)
Application Number:
05/318121
Publication Date:
05/07/1974
Filing Date:
12/26/1972
View Patent Images:
Export Citation:
Primary Class:
Other Classes:
182/198
International Classes:
E06C9/14; E06C9/00; E06C9/14
Field of Search:
182/70,71,72,73,74,198
Primary Examiner:
Machado, Reinaldo P.
Attorney, Agent or Firm:
Frater, Grover A.
Claims:
1. In a retractable ladder assembly, in combination:
2. In a retractable ladder assembly, in combination:
3. The invention defined in claim 2 which further comprises a frame, said container being fixed to the frame; elements of said frame extending beyond the margins of said box at opposite sides thereof; a fixed ladder carried by said frame and including a pair of hand rails disposed on opposite sides of said box and extending to a point spaced from said front wall of the container, and a step connected between said hand rails such that it overlies but is spaced from said front wall of said container.
2. In a retractable ladder assembly, in combination:
3. The invention defined in claim 2 which further comprises a frame, said container being fixed to the frame; elements of said frame extending beyond the margins of said box at opposite sides thereof; a fixed ladder carried by said frame and including a pair of hand rails disposed on opposite sides of said box and extending to a point spaced from said front wall of the container, and a step connected between said hand rails such that it overlies but is spaced from said front wall of said container.
Description:
This invention relates to improvements in retractable ladders.
The invention relates particularly to a "flexible ladder" which comprises a pair of chains or ropes or other flexible lines and a number of rungs, each of which is secured between lines. The lines have their upper ends suspended from an overhead structure. While there are other applications for such a ladder, a chief use is to provide an escape route from a burning building.
It is an object of this invention to provide an improved retractable ladder of general application. Nonetheless, the preferred embodiment of the invention is particularly well suited for use as a retractable, emergency, escape ladder. To provide an improved apparatus for that application is another of the objects of the invention.
An escape ladder is one that extends from the roof or from a window or other exterior opening in a building down the side of the building wall. Some escape ladders are rigid structures mounted on the exterior of the building. Others are hook-type flexible ladders carried as lifesaving apparatus by organized firefighters. That kind usually consists of a rope or chain ladder which is fitted with hooks at its upper end that can be hooked over a window sill or the like. Unlike those devices, this invention provides a structure which may be installed permanently on the side of the building but which has the advantages of rope and chain ladders and can be retracted.
There is a need to store escape ladders out of the reach of intruders lest burglars and vandals use them to gain admittance to the building with which the ladder is associated. An escape ladder must be available for use at any time and it must be available almost instantly in an emergency. If retracted, it must be capable of being extended easily, unerringly, with a minimum force, by a procedure which will be obvious and natural. Persons who need to use an emergency escape ladder can be expected to be hurried and excited. An object of the invention is to provide an escape ladder which is easily lowered with a small force applied in a natural manner, retractable, and is immediately available for use in an emergency. More particularly, it is an object to provide an emergency ladder which will be lowered by a downward force applied, in the preferred embodiment, to the upper wall of the container in which the retractable ladder is housed when not in use.
An emergency ladder might go unused and unattended for years so its structure must be one that does not deteriorate with time. It must be protected from the elements or be immune from their effect. On the other hand, a ladder might be used relatively frequently in fire drill and, lest the complexity and difficulty of its retraction operate to discourage such fire drills, the good retractable ladder is one that is easily retracted. It is an object of the invention to provide, and it does provide, a retractable ladder arrangement in which the ladder is enclosed in a storage container whenever it is not in use and which is easily restored in the container from above. In the invention, the ladder is stored in a relatively small container which is fixed to the side of a building just below a window or other access point. The manner of attachment will vary depending upon the building construction. However, the container is mounted on a supporting frame which is perforated to receive fastening elements for direct connection to the building or to mounting elements which are in turn fixed to the building. The container is adequate to keep snow and rain from reaching the ladder stored within. It is sufficiently small so that it is feasible to give it a good protective coating against the action of the elements whereby a minimum amount of servicing is required to maintain its good appearance.
The containing box is provided with an upper and a lower door. The lower door is latched shut in a way that makes it secure from operation from below by would-be intruders. The upper door opens to afford access to the interior of the container so that the ladder can be retracted by pulling it up into the container and through the container from above. The provision of that kind of structural arrangement is another of the objects of the invention.
There is both an apparent and a real danger in climbing out of a window onto a flexible ladder. That presents two problems. One is how to make the structure safe to use and the other is how to make the structure look safe to use. An escape ladder is of little use to one who is afraid to use it. It is an object of this invention to provide an escape ladder which is safe and looks safe. It is an object to provide a ladder whose upper end and whose first few steps are solid and unmoving and to provide a structure in which one reaches the flexible part of the ladder only after he is out of the window and facing the building with his body vertical or nearly so. This result is accomplished by making the upper portion of the ladder a fixed structure arranged so that its hand-holding portions and rungs are spaced from the building. The container for the retractable portion of the ladder is placed between the hand-holds and between the rungs and the building. It is positioned so that its upper wall serves both as a first step and a place for the user to kneel while backing out of the window. The provision of that kind of structure is another object of the invention. In the preferred embodiment the upper wall is the upper cover of the container and is the actuator for the mechanism that releases the lower exit door for the ladder. That latching mechanism will operate to release the ladder when one pushes, stands, pounds or otherwise applies force to the upper cover.
The invention provides a safe, easy to use, easily maintained, easily released and easily retracted structure which can be produced at relatively low cost.
These and other objects and advantages of the invention will be apparent upon an examination of the detailed specification that follows together with the drawings, in which:
FIG. 1 is an isometric view of a retractable, enclosed ladder structure embodying the invention and mounted in place on the wall of a building with the ladder shown fragmented;
FIG. 2 is a cross-sectional view of the ladder structure of FIG. 1 shown with its ladder retracted into the closed container of the unit; it is taken on line 2--2 of FIG. 3;
FIG. 3 is a cross-sectional view taken on line 3--3 of FIG. 2;
FIG. 4 is a cross-sectional view of the upper end of the container as viewed in FIG. 2 except that it is enlarged;
FIG. 5 is an isometric, fragmented view of the latching mechanism of the structure;
FIG. 6 is a cross-sectional view of the latching mechanism taken on line 6--6 of FIG. 3; and
FIG. 7 is an isometric view of one of the rungs, and some of the links, of the retractable ladder.
In FIG. 1 the retractable ladder unit 10 is secured to the wall 12 of a building just below window 14. The unit includes a chain ladder 16, a container 17 for the chain ladder, left and right side handholds in the form of handrails 18 and 19, a rear frame 20, an upper rung or step 21 and a lower rung or step 22. In the installation shown, the frame is attached to the building directly.
In this embodiment the frame comprises two elongated, parallel angle irons 26 and 28. They are interconnected near their upper end by a crossbar 30 and near their lower ends by a crossbar 31 which may be seen in FIGS. 2, 3 and 4. The container 17 is rectangular in top and bottom plan view. Its rear wall 32 is fitted between the angle irons 26 and 28. Side wall 34 abuts the inner wall of angle iron 28 and the other side wall 36 abuts the inner wall of angle iron 26 so that the rear vertical corners of the container nest within the angle irons 26 and 28 over an intermediate distance of their length. Thus, the two angle irons extend both above and below the container. The container is bolted to the frame 20 by being bolted to cross members 30 and 31. The forward outer wall of the container is designated 38.
It has a channel 40 fitted to its inner surface. The channel serves to protect and house the latch operating mechanism as best shown in FIG. 5. In FIG. 3 it is seen that the channel is disposed with its channel opening toward the front wall 38 of the container and it is located midway between the two sidewalls 34 and 36. It extends over the entire vertical height of the forward wall as best shown in FIG. 2.
The front, back, top, side walls and bottom of the container 17 are all rectangular. The bottom wall is perpendicular to the sides, front and back. It comprises a door which swings downwardly around its rear edge where it is welded to one leaf of a piano hinge 44. The other leaf of that hinge is welded to the rear wall 32. The bottom wall 46 is provided with a slot 48 which accommodates the C-shaped latch dog 50.
The upper wall 54 slopes slightly downwardly from the rear edge next to the building to its forward edge. That slope tends to discharge rain and melting snow and it serves to prompt an escapee kneeling on it to let go of the window frame and to grasp the handrails and seek the step or rung at the front of the container. That upper wall also serves as a cover or lid. It is secured along its rear edge to one leaf of a piano hinge 56 whose other leaf is welded to the rear wall 32 of the container. The cover is provided with a lip 58 which extends downwardly at its front and sides to cover the upper edges of the forward wall 38 and the two side walls 34 and 36.
It will be seen in FIGS. 2 and 4 that the cover 54 does not fit down solidly against the upper edge 60 of the side wall 36 nor does it fit tightly against the upper edge of the forward wall 38. Similarly, although not visible in the drawings, the cover 54 does not rest on the upper edge of the other side wall 34. Instead, the upper wall or cover 54 is held spaced from the upper edge of the container walls by the upper end 62 of a latching rod 64. That latching rod is also visible in FIG. 5 at the top of the latching rod 64. The channel 40 is arranged so that it has a pair of forward, sidewardly extending flanges by which the channel is spot welded to the inner surface of the wall 38.
Two pins are securely fixed to the rear wall, the wall at the bottom of the channel, and extend forwardly from that wall. One of those pins is located midway along the length of the channel 40 and the other is located near its lower end. The upper pin 67 serves as a guide for the latching rod 64 and as an anchor for the upper end of a spring 68 whose lower end is pinned at 69 to the latch dog 50. The other pin 70 extends through the latch dog and serves as a pivot for its rotation. The pin 67 extends through an elongated slot 72 formed in the actuating rod 64. Thus the rod is free to move up and down in a generally vertical direction while being prevented from rotating about pivot pin 73 by which the lower end of the actuating rod is pivotally connected to the upper end of the latch dog 50. The pin 69 is located between pivots 70 and 73 whereby it will be apparent, upon examination of FIG. 5, that the spring 68 serves not only to bias the latch dog against clockwise rotation about pivot pin 70 but it also tends to hold the actuating rod 64 in an upward direction so that the upper end 62 of the actuating rod extends above the upper edge of the channel 40. In FIG. 4 it will be seen that the cover 54 of the container rests upon upper end 62 of the actuating rod. When that cover is pushed down, the actuating rod 64 is pushed downwardly. Downward motion applies a force through pivot 73 to the latch dog 50 which tends to rotate the dog against the bias of spring 68 in a clockwise direction around pivot 70. That action and its effect can be more easily visualized by examination of FIG. 6. The latch dog extends through slot 48 of the lower wall 46 with the upper part of the lower arm of the C of its C-shape engaged against the lower surface of the door 46. The upper surface of that C-shape of the lower arm of the C-shape is made flat so that it will engage the flat under surface of lower door 46 whereby there is no tendency for pressure of the door to cam that latch dog open. Instead, the several parts will have the position shown in FIG. 6 until pressure on the door 54 above forces the actuating rod 64 down to force the latch dog into counterclockwise rotation in a degree sufficient for the lower arm of the dog to clear the under surface of the lower door. As soon as that happens, door 46 is free to swing open and it does swing open under the weight of the ladder bearing down upon it from above. Element 74 is a hat-shaped bracket which is welded to the under surface of lower door 46 over the slot 48. Its purpose is to make the latch dog 50 inaccessible from below to burglars who might attempt to trip the latch to gain access to the ladder.
There are no protrusions on the door so there is no place for the ladder elements to catch. They simply fall down until the ladder is extended to its full length. The upper ends of the ladder chains are bolted through the rear wall 32 to the cross member 30 so that there is a direct connection from the ladder chains to the frame of the unit. The ladder is restored to the container by opening the upper door wide and then reaching into the container to grasp the upper portion of the ladder. The whole ladder is pulled up hand-over-hand until most or all of it lies above the container. Then the lower door is closed. That lower door is easily reached by reaching past the container. It is swung closed and latched shut. Then the ladder is played back into the container until all of it resides there. The upper cover 54 is lowered down until it engages the upper end of the actuator rod. The latch is not operated by the weight of the cover 54. The spring 74 is sufficiently strong to preclude operation by the weight of the cover alone. It is necessary to press or lean on the cover or to pound on it with one's fist to release the door. Certainly, the weight of a person kneeling on that cover is more than adequate to release the ladder.
It is preferred that the structure be mounted at the side of the wall so that the cover 54 is substantially at the level of the window sill as shown in FIG. 1. That makes it easy to use the upper cover as a platform on which to kneel while going out of the window and it puts the hand holds up at an easily accessible level. The hand holds are the side rails. They extend from a point at the upper end of the angle irons downwardly and outwardly to a point several inches in front of the front wall of the box and then downwardly to a point below the end of the box and then are bent back into a connection to the end of the angle iron below the box. The dimensions of the unit are such that the cross members 21 and 22 can and do serve as ladder steps or rungs. The unit shown in the drawings has a ladder long enough to reach to ground level when it is mounted below a third story window. The container in that embodiment is seventeen and five-eigths inches wide. Its rear wall is twenty-two and one-eighth inches high and its forward wall is 22 inches high. The front and rear walls are separated by four and one-half inches. The side rails are connected to the angle irons at points sixteen inches apart. The rail stands approximately eight inches from the angle irons. That arrangement provides sufficient clearance between the rungs 21 and 22 and the forward wall of the container so that the rungs can safely be used as a step. One rung is employed in the two-story ladder because its container is less high. The object is to use rung placement to indicate to the user how far apart the steps are placed. The purpose is to eliminate the anxiety that might arise if the step below was not where the user anticipated that it would be.
A preferred form of rung is shown in FIG. 7. It comprises a rectangular bar 80. Each of a pair of chain links 81 and 82 is bolted to a respectively associated end of the bar 80 so that the links extend in like direction. The other chain links are linked to those end links 81 and 82 to form the ladder whose rungs are mounted approximately 14 inches apart. The rungs are made sufficiently long in relation to the width of the storage box so that all of the bars lay approximately parallel within the box. In this embodiment the rungs are fourteen inches long. The links 81 and 82 are bolted to the rung by a trough bolt and cap nuts. A washer 83 centers the assembly at each end of the rung.
The rung 80 is the second one down from the container when the ladder is extended. It differs from the other in that it is provided with two spacer projections 84 which extend perpendicular to the rung in the direction toward the building. These spacers prevent the ladder from assuming a position flat against the building wall in which the rungs would be difficult to step upon. Only one such spacer rung is required and it should be the second one down from the container as shown in FIG. 1. All of the other rungs are like rung 80 except that they omit the spacer elements 84. It is not necessary that the bottom cover fit tightly to the body of the container. In fact, it is preferable that the lower door fit loosely so that air may flow freely through the unit. The purpose is to minimize condensation and to permit any condensation to flow away freely. That bottom cover should be made of material strong enough to hold the weight of the ladder without bending or sagging. On the other hand, both the lower and upper covers are made of material which can be bent by the application of extra force. Even if the upper hinge becomes frozen so that the upper door cannot rotate on the hinge, the cover will bend sufficiently to permit actuation of the actuating rod. If the lower hinge should become frozen the application of additional force by pressing down on the retracted ladder from above will bend the bottom cover sufficiently to permit the ladder to be released. The structure is such that frozen hinges can be prevented with a very minimum of maintenance. However, the construction is such that the apparatus can be made to operate and the ladder lowered even though the unit suffers years of neglect.
To use the device, one opens the window and presses down on the cover 54 to release the ladder. The user then backs out of the window kneeling on the upper cover 54. The upper end of the side rails is then grasped and the user probes for one of the rungs with his feet. Ordinarily, he will step first on the lower rung 22. The rung 21 is placed near the upper edge of the box where it will be touched by the user's foot. Thus, the user is given a tactile signal to indicate that the rung can be reached and it provides a way to indicate to the user how far down he must lower his foot to reach the next step. Rung 21 will ordinarily be used as a hand hold rather than as a step. Once the user is standing on the rung 22 the more difficult part of the task has been completed and from then on it is simply a question of moving down the ladder.
While it is possible, and contemplated within the invention, to produce longer ladders, the fact that downward pressure on the cover occasions release makes it possible to use several ladders in series on higher buildings. That is preferred so that it is unnecessary to go to a higher floor to release a long ladder.
Although we have shown and described certain specific embodiments of our invention, we are fully aware that many modifications thereof are possible. Our invention, therefore, is not to be restricted except insofar as is necessitated by the prior art.
The invention relates particularly to a "flexible ladder" which comprises a pair of chains or ropes or other flexible lines and a number of rungs, each of which is secured between lines. The lines have their upper ends suspended from an overhead structure. While there are other applications for such a ladder, a chief use is to provide an escape route from a burning building.
It is an object of this invention to provide an improved retractable ladder of general application. Nonetheless, the preferred embodiment of the invention is particularly well suited for use as a retractable, emergency, escape ladder. To provide an improved apparatus for that application is another of the objects of the invention.
An escape ladder is one that extends from the roof or from a window or other exterior opening in a building down the side of the building wall. Some escape ladders are rigid structures mounted on the exterior of the building. Others are hook-type flexible ladders carried as lifesaving apparatus by organized firefighters. That kind usually consists of a rope or chain ladder which is fitted with hooks at its upper end that can be hooked over a window sill or the like. Unlike those devices, this invention provides a structure which may be installed permanently on the side of the building but which has the advantages of rope and chain ladders and can be retracted.
There is a need to store escape ladders out of the reach of intruders lest burglars and vandals use them to gain admittance to the building with which the ladder is associated. An escape ladder must be available for use at any time and it must be available almost instantly in an emergency. If retracted, it must be capable of being extended easily, unerringly, with a minimum force, by a procedure which will be obvious and natural. Persons who need to use an emergency escape ladder can be expected to be hurried and excited. An object of the invention is to provide an escape ladder which is easily lowered with a small force applied in a natural manner, retractable, and is immediately available for use in an emergency. More particularly, it is an object to provide an emergency ladder which will be lowered by a downward force applied, in the preferred embodiment, to the upper wall of the container in which the retractable ladder is housed when not in use.
An emergency ladder might go unused and unattended for years so its structure must be one that does not deteriorate with time. It must be protected from the elements or be immune from their effect. On the other hand, a ladder might be used relatively frequently in fire drill and, lest the complexity and difficulty of its retraction operate to discourage such fire drills, the good retractable ladder is one that is easily retracted. It is an object of the invention to provide, and it does provide, a retractable ladder arrangement in which the ladder is enclosed in a storage container whenever it is not in use and which is easily restored in the container from above. In the invention, the ladder is stored in a relatively small container which is fixed to the side of a building just below a window or other access point. The manner of attachment will vary depending upon the building construction. However, the container is mounted on a supporting frame which is perforated to receive fastening elements for direct connection to the building or to mounting elements which are in turn fixed to the building. The container is adequate to keep snow and rain from reaching the ladder stored within. It is sufficiently small so that it is feasible to give it a good protective coating against the action of the elements whereby a minimum amount of servicing is required to maintain its good appearance.
The containing box is provided with an upper and a lower door. The lower door is latched shut in a way that makes it secure from operation from below by would-be intruders. The upper door opens to afford access to the interior of the container so that the ladder can be retracted by pulling it up into the container and through the container from above. The provision of that kind of structural arrangement is another of the objects of the invention.
There is both an apparent and a real danger in climbing out of a window onto a flexible ladder. That presents two problems. One is how to make the structure safe to use and the other is how to make the structure look safe to use. An escape ladder is of little use to one who is afraid to use it. It is an object of this invention to provide an escape ladder which is safe and looks safe. It is an object to provide a ladder whose upper end and whose first few steps are solid and unmoving and to provide a structure in which one reaches the flexible part of the ladder only after he is out of the window and facing the building with his body vertical or nearly so. This result is accomplished by making the upper portion of the ladder a fixed structure arranged so that its hand-holding portions and rungs are spaced from the building. The container for the retractable portion of the ladder is placed between the hand-holds and between the rungs and the building. It is positioned so that its upper wall serves both as a first step and a place for the user to kneel while backing out of the window. The provision of that kind of structure is another object of the invention. In the preferred embodiment the upper wall is the upper cover of the container and is the actuator for the mechanism that releases the lower exit door for the ladder. That latching mechanism will operate to release the ladder when one pushes, stands, pounds or otherwise applies force to the upper cover.
The invention provides a safe, easy to use, easily maintained, easily released and easily retracted structure which can be produced at relatively low cost.
These and other objects and advantages of the invention will be apparent upon an examination of the detailed specification that follows together with the drawings, in which:
FIG. 1 is an isometric view of a retractable, enclosed ladder structure embodying the invention and mounted in place on the wall of a building with the ladder shown fragmented;
FIG. 2 is a cross-sectional view of the ladder structure of FIG. 1 shown with its ladder retracted into the closed container of the unit; it is taken on line 2--2 of FIG. 3;
FIG. 3 is a cross-sectional view taken on line 3--3 of FIG. 2;
FIG. 4 is a cross-sectional view of the upper end of the container as viewed in FIG. 2 except that it is enlarged;
FIG. 5 is an isometric, fragmented view of the latching mechanism of the structure;
FIG. 6 is a cross-sectional view of the latching mechanism taken on line 6--6 of FIG. 3; and
FIG. 7 is an isometric view of one of the rungs, and some of the links, of the retractable ladder.
In FIG. 1 the retractable ladder unit 10 is secured to the wall 12 of a building just below window 14. The unit includes a chain ladder 16, a container 17 for the chain ladder, left and right side handholds in the form of handrails 18 and 19, a rear frame 20, an upper rung or step 21 and a lower rung or step 22. In the installation shown, the frame is attached to the building directly.
In this embodiment the frame comprises two elongated, parallel angle irons 26 and 28. They are interconnected near their upper end by a crossbar 30 and near their lower ends by a crossbar 31 which may be seen in FIGS. 2, 3 and 4. The container 17 is rectangular in top and bottom plan view. Its rear wall 32 is fitted between the angle irons 26 and 28. Side wall 34 abuts the inner wall of angle iron 28 and the other side wall 36 abuts the inner wall of angle iron 26 so that the rear vertical corners of the container nest within the angle irons 26 and 28 over an intermediate distance of their length. Thus, the two angle irons extend both above and below the container. The container is bolted to the frame 20 by being bolted to cross members 30 and 31. The forward outer wall of the container is designated 38.
It has a channel 40 fitted to its inner surface. The channel serves to protect and house the latch operating mechanism as best shown in FIG. 5. In FIG. 3 it is seen that the channel is disposed with its channel opening toward the front wall 38 of the container and it is located midway between the two sidewalls 34 and 36. It extends over the entire vertical height of the forward wall as best shown in FIG. 2.
The front, back, top, side walls and bottom of the container 17 are all rectangular. The bottom wall is perpendicular to the sides, front and back. It comprises a door which swings downwardly around its rear edge where it is welded to one leaf of a piano hinge 44. The other leaf of that hinge is welded to the rear wall 32. The bottom wall 46 is provided with a slot 48 which accommodates the C-shaped latch dog 50.
The upper wall 54 slopes slightly downwardly from the rear edge next to the building to its forward edge. That slope tends to discharge rain and melting snow and it serves to prompt an escapee kneeling on it to let go of the window frame and to grasp the handrails and seek the step or rung at the front of the container. That upper wall also serves as a cover or lid. It is secured along its rear edge to one leaf of a piano hinge 56 whose other leaf is welded to the rear wall 32 of the container. The cover is provided with a lip 58 which extends downwardly at its front and sides to cover the upper edges of the forward wall 38 and the two side walls 34 and 36.
It will be seen in FIGS. 2 and 4 that the cover 54 does not fit down solidly against the upper edge 60 of the side wall 36 nor does it fit tightly against the upper edge of the forward wall 38. Similarly, although not visible in the drawings, the cover 54 does not rest on the upper edge of the other side wall 34. Instead, the upper wall or cover 54 is held spaced from the upper edge of the container walls by the upper end 62 of a latching rod 64. That latching rod is also visible in FIG. 5 at the top of the latching rod 64. The channel 40 is arranged so that it has a pair of forward, sidewardly extending flanges by which the channel is spot welded to the inner surface of the wall 38.
Two pins are securely fixed to the rear wall, the wall at the bottom of the channel, and extend forwardly from that wall. One of those pins is located midway along the length of the channel 40 and the other is located near its lower end. The upper pin 67 serves as a guide for the latching rod 64 and as an anchor for the upper end of a spring 68 whose lower end is pinned at 69 to the latch dog 50. The other pin 70 extends through the latch dog and serves as a pivot for its rotation. The pin 67 extends through an elongated slot 72 formed in the actuating rod 64. Thus the rod is free to move up and down in a generally vertical direction while being prevented from rotating about pivot pin 73 by which the lower end of the actuating rod is pivotally connected to the upper end of the latch dog 50. The pin 69 is located between pivots 70 and 73 whereby it will be apparent, upon examination of FIG. 5, that the spring 68 serves not only to bias the latch dog against clockwise rotation about pivot pin 70 but it also tends to hold the actuating rod 64 in an upward direction so that the upper end 62 of the actuating rod extends above the upper edge of the channel 40. In FIG. 4 it will be seen that the cover 54 of the container rests upon upper end 62 of the actuating rod. When that cover is pushed down, the actuating rod 64 is pushed downwardly. Downward motion applies a force through pivot 73 to the latch dog 50 which tends to rotate the dog against the bias of spring 68 in a clockwise direction around pivot 70. That action and its effect can be more easily visualized by examination of FIG. 6. The latch dog extends through slot 48 of the lower wall 46 with the upper part of the lower arm of the C of its C-shape engaged against the lower surface of the door 46. The upper surface of that C-shape of the lower arm of the C-shape is made flat so that it will engage the flat under surface of lower door 46 whereby there is no tendency for pressure of the door to cam that latch dog open. Instead, the several parts will have the position shown in FIG. 6 until pressure on the door 54 above forces the actuating rod 64 down to force the latch dog into counterclockwise rotation in a degree sufficient for the lower arm of the dog to clear the under surface of the lower door. As soon as that happens, door 46 is free to swing open and it does swing open under the weight of the ladder bearing down upon it from above. Element 74 is a hat-shaped bracket which is welded to the under surface of lower door 46 over the slot 48. Its purpose is to make the latch dog 50 inaccessible from below to burglars who might attempt to trip the latch to gain access to the ladder.
There are no protrusions on the door so there is no place for the ladder elements to catch. They simply fall down until the ladder is extended to its full length. The upper ends of the ladder chains are bolted through the rear wall 32 to the cross member 30 so that there is a direct connection from the ladder chains to the frame of the unit. The ladder is restored to the container by opening the upper door wide and then reaching into the container to grasp the upper portion of the ladder. The whole ladder is pulled up hand-over-hand until most or all of it lies above the container. Then the lower door is closed. That lower door is easily reached by reaching past the container. It is swung closed and latched shut. Then the ladder is played back into the container until all of it resides there. The upper cover 54 is lowered down until it engages the upper end of the actuator rod. The latch is not operated by the weight of the cover 54. The spring 74 is sufficiently strong to preclude operation by the weight of the cover alone. It is necessary to press or lean on the cover or to pound on it with one's fist to release the door. Certainly, the weight of a person kneeling on that cover is more than adequate to release the ladder.
It is preferred that the structure be mounted at the side of the wall so that the cover 54 is substantially at the level of the window sill as shown in FIG. 1. That makes it easy to use the upper cover as a platform on which to kneel while going out of the window and it puts the hand holds up at an easily accessible level. The hand holds are the side rails. They extend from a point at the upper end of the angle irons downwardly and outwardly to a point several inches in front of the front wall of the box and then downwardly to a point below the end of the box and then are bent back into a connection to the end of the angle iron below the box. The dimensions of the unit are such that the cross members 21 and 22 can and do serve as ladder steps or rungs. The unit shown in the drawings has a ladder long enough to reach to ground level when it is mounted below a third story window. The container in that embodiment is seventeen and five-eigths inches wide. Its rear wall is twenty-two and one-eighth inches high and its forward wall is 22 inches high. The front and rear walls are separated by four and one-half inches. The side rails are connected to the angle irons at points sixteen inches apart. The rail stands approximately eight inches from the angle irons. That arrangement provides sufficient clearance between the rungs 21 and 22 and the forward wall of the container so that the rungs can safely be used as a step. One rung is employed in the two-story ladder because its container is less high. The object is to use rung placement to indicate to the user how far apart the steps are placed. The purpose is to eliminate the anxiety that might arise if the step below was not where the user anticipated that it would be.
A preferred form of rung is shown in FIG. 7. It comprises a rectangular bar 80. Each of a pair of chain links 81 and 82 is bolted to a respectively associated end of the bar 80 so that the links extend in like direction. The other chain links are linked to those end links 81 and 82 to form the ladder whose rungs are mounted approximately 14 inches apart. The rungs are made sufficiently long in relation to the width of the storage box so that all of the bars lay approximately parallel within the box. In this embodiment the rungs are fourteen inches long. The links 81 and 82 are bolted to the rung by a trough bolt and cap nuts. A washer 83 centers the assembly at each end of the rung.
The rung 80 is the second one down from the container when the ladder is extended. It differs from the other in that it is provided with two spacer projections 84 which extend perpendicular to the rung in the direction toward the building. These spacers prevent the ladder from assuming a position flat against the building wall in which the rungs would be difficult to step upon. Only one such spacer rung is required and it should be the second one down from the container as shown in FIG. 1. All of the other rungs are like rung 80 except that they omit the spacer elements 84. It is not necessary that the bottom cover fit tightly to the body of the container. In fact, it is preferable that the lower door fit loosely so that air may flow freely through the unit. The purpose is to minimize condensation and to permit any condensation to flow away freely. That bottom cover should be made of material strong enough to hold the weight of the ladder without bending or sagging. On the other hand, both the lower and upper covers are made of material which can be bent by the application of extra force. Even if the upper hinge becomes frozen so that the upper door cannot rotate on the hinge, the cover will bend sufficiently to permit actuation of the actuating rod. If the lower hinge should become frozen the application of additional force by pressing down on the retracted ladder from above will bend the bottom cover sufficiently to permit the ladder to be released. The structure is such that frozen hinges can be prevented with a very minimum of maintenance. However, the construction is such that the apparatus can be made to operate and the ladder lowered even though the unit suffers years of neglect.
To use the device, one opens the window and presses down on the cover 54 to release the ladder. The user then backs out of the window kneeling on the upper cover 54. The upper end of the side rails is then grasped and the user probes for one of the rungs with his feet. Ordinarily, he will step first on the lower rung 22. The rung 21 is placed near the upper edge of the box where it will be touched by the user's foot. Thus, the user is given a tactile signal to indicate that the rung can be reached and it provides a way to indicate to the user how far down he must lower his foot to reach the next step. Rung 21 will ordinarily be used as a hand hold rather than as a step. Once the user is standing on the rung 22 the more difficult part of the task has been completed and from then on it is simply a question of moving down the ladder.
While it is possible, and contemplated within the invention, to produce longer ladders, the fact that downward pressure on the cover occasions release makes it possible to use several ladders in series on higher buildings. That is preferred so that it is unnecessary to go to a higher floor to release a long ladder.
Although we have shown and described certain specific embodiments of our invention, we are fully aware that many modifications thereof are possible. Our invention, therefore, is not to be restricted except insofar as is necessitated by the prior art.