LADDER ATTACHMENT
United States Patent 3653462
A device for attachment to a ladder which enables the ladder to bridge windows and distribute the force of the ladder over a larger area thereby providing a greater margin of safety against the ladder sliding off the building and at the same time a greater freedom in the work area yet be lighter and inexpensive.
US Patent References:
Safety device for ladders
Seaman - June 1926 - 1590064
Safety attachment for ladders
Hansen - April 1931 - 1800792
Self-locking safety support for ladders
Russell - August 1968 - 3395776
Safety device for ladders
Seaman - June 1926 - 1590064
Safety attachment for ladders
Hansen - April 1931 - 1800792
Self-locking safety support for ladders
Russell - August 1968 - 3395776
Application Number:
05/048384
Publication Date:
04/04/1972
Filing Date:
06/22/1970
View Patent Images:
Export Citation:
Primary Class:
Other Classes:
182/214
International Classes:
E06C7/48; E06C7/00; E06C7/48; E06C5/36
Field of Search:
182/214,107,108
Primary Examiner:
Machado, Reinaldo P.
Claims:
I claim
1. A ladder attachment comprising:
2. A ladder attachment according to claim 1 wherein said adjustable foot means include,
3. A ladder attachment according to claim 2 wherein said foot means has a coating of abrasive resistant coating.
4. A ladder attachment according to claim 3 wherein said attachment is lightweight metal.
1. A ladder attachment comprising:
2. A ladder attachment according to claim 1 wherein said adjustable foot means include,
3. A ladder attachment according to claim 2 wherein said foot means has a coating of abrasive resistant coating.
4. A ladder attachment according to claim 3 wherein said attachment is lightweight metal.
Description:
Conventional ladders are placed against buildings when work is required above ground. Ladders are rather expensive yet a great number are owned by home owners. These ladders without exception are designed such that the side rails are but a couple of feet apart at the most and are so designed they terminate at a very small point contact in two places against the building. Furthermore, the trend with ladders is to light weight material such as aluminum.
Along with the changes in ladders as to material, particularly that of aluminum, the siding on buildings has undergone dramatic changes as well. There's a great popularity in use of aluminum siding as well as vinyl shingle siding. In both instances these materials cannot support a very narrow point contact that is established by the conventional ladder without deformation of total destruction. Therefore, a significant problem with the modern siding is that of breakage or deformation as a result of the use of ladders.
The lightweight design of aluminum ladders makes for increased portability and flexibility in placing the ladder. However, coupled with the problem of destroying siding on a house is a distinct safety problem. With two small point contacts of a lightweight ladder against the building and no one on the ladder, a simple light breeze is all that is needed to lift the ladder slightly. If it is slightly ajar on the ground, (that is a small angle of inclination toward any one direction), the ladder will slide off of the building, crash to the ground, and cause severe injury to people or passerbys. This difficulty with the aluminum ladder is also present when someone is on the ladder because although the force against the building is greater, it may not be significant enough to provide enough friction with a slightly higher wind. Accordingly, the lightweight of the ladder and the small point contact present very severe problems.
Another difficulty with a ladder of conventional design is that the rails are so close to the building in the work area, that is the painter or repairman encounters some difficulty. Therefore, any scheme which would hold the latter out from the building slightly would provide a distinct advantage which would enable one to work more effectively in the area where the ladder is making contact with the building. And if the contacts were extended out from the rails any distance, the ladder would be used very effectively while working on windows because the contacts would straddle the window providing much more ease for working in such areas.
Prior art devices have been suggested to meet some of the above problems. For one thing, many designs have been made to straddle windows; however, even the straddle arrangement usually ended up in a very small point contact against the building which would only provide for the solution of one problem--that of straddling the window. Another difficulty that was not provided for, therefore, was the destruction of shingles or siding; and the safety factor of lifting the ladder slightly out from the wall by a breeze enabling it to fall to the ground. The prior art device referred to here invariably was of unitary design and extremely heavy. Therefore, users could not attach or detach the unit easily and when they attached it, they would have difficulty in placing the unit--ladder, that is--with the attachment thereto against the building owing to its great weight. The present invention was therefore devised which could straddle a window as in prior art devices but would be of exceedingly lower weight, at the same time its cost would be much lower. Its ability to be attached to a ladder significantly more easy providing decided advantages over the prior art devices especially for those with the greatest need--that of the home owner.
The greatest single advantage of the present invention is not that of straddling the window. It is, however, that of a safety factor which the present invention provides for it does not make minimal contact with a wall. It provides a considerable area of friction material which spreads itself against the wall and at the same time a flexible spring-like action of the device along with the ladder provides a bias which no single slight breeze can release permitting the ladder to slide off the building. And when a customer who has purchased the ladder is using it some several feet above the ground, he cannot rock the ladder or cause it to slide. He must disembark from the ladder and move it from the ground.
Not unlike the prior art the present invention will straddle the wall or window that may be desired to be worked on. Moreover, the present invention, which does not have a unitary design, permits one to work freely within the center of the ladder where the work is chiefly to be conducted; because of its two piece nature, it does not block or obstruct the area between the rails.
Therefore, an object of the present invention is to provide a ladder attachment having two separate units.
Another object of the present invention is to provide a two-unit (lightweight) attachment for ladders.
Another object of the present invention is to provide a two-unit ladder attachment which provides an inherent bias preventing the ladder from sliding off of the building.
Another object of the present invention is to provide a sponge-like, flexible foot for attachment to a ladder which distributes the force of the ladder in contact with the building preventing indentation or destruction of siding or shingles.
Other objects and advantages of the present invention will be better understood from the following specification when read in conjunction with the attached drawings of which:
FIG. 1 is the top of a ladder with the invention attached.
FIG. 2 is a ladder leaning against a building with the ladder attachment.
FIG. 3 is a closeup top view of a ladder attachment accorded to the present invention.
FIG. 4 is a rail support bar according to the present invention.
FIG. 5 is a foot for the ladder attachment which comes in contact with the building.
FIG. 6 is a section of the ladder attachment.
FIG. 7 is a lower portion of the ladder attachment 12.
Referring to FIG. 1 we see a ladder 11 with two identical devices in accordance with the present invention which are attached to the rails of the ladder--they are designated 12 and 13.
In FIG. 2 we see the ladder 11 against a building 14 and the attachment 13 is shown holding the ladder out from the building at a prescribed distance.
The individual units 12 and 13 when attached to the ladder obviously can span considerable distance such that they can span the distance of a window as many of the conventional prior art devices could do. However, the fact that they are two single independent units provides something rather unique. Their weight is only a fraction of the prior art devices yet it provides much more facility for working at the top of a ladder in and about the window because the center portion is no longer their obstructing one's effort particularly that of painting or repairing parts of the window.
Another advantage of the present invention in its spanning quality is with modern siding of very thin gauged steel or aluminum, it is wise to spread the forces of the ladder onto more than one shingle. With the present invention 12 and 13 may be offset from one another such that they do not line up directly on the same single or row of shingles. Furthermore, the distance apart that these units come in contact with the building are such that a greater distribution of force is achieved which also prevents the shingle from being injured. As we will see further, the present invention makes other provisions which prevents injury to siding.
Referring to FIG. 3 we see an individual unit in much greater detail. 12 as shown has a triangular reinforcement structure, 21. Within the box-like structure formed by the altitude leg of the triangular structure, a movable piece 23, rod 24, and that portion which is an extension of the base of the triangle is utilized to enclose the railing of the ladder. It is placed over a ladder rail and rod 24 is pushed in as close as possible within track 48 and track 42 then thumb screw 25 is turned until 23 presses against the ladder rail 11. Thumb screw 6 is then tightened on screw 22 so that symmetrical force provides a secure contact to the ladder rail. Another identical attachment can be attached to the other railing as 13 but flipped over. Each unit is identical and will be attached in the same manner. Screw 27 is about a foot out from the edge of the ladder railing and has a foot plate 31 attached to the screw and compressible rubber material 32 attached to the foot plate. Two thumb screws 28 and 29 enable it to be positioned in or out from the ladder rail so that a symmetrical or unsymmetrical position can be attained about the ladder so that flat surfaces of buildings and sloping surfaces can be equally accommodated.
Referring to FIG. 4 we see piece 23 which comes in contact with a portion of ladder rail. 23 has a hole 41 for screw 22 which can be tightened to maintain a pressure on the rail. So too, can 24 be tightened with a thumb screw 25; however, in this event slot 42 permits rod 24 to slide in or out such that a closer control over the pressure on the railing is provided. Furthermore, notches 46 and 47 permit the piece 23 to slide up and down freely in slot 49 yet be unable to slip out of triangular member 21.
Referring to FIG. 6 we see an end view of 23 as it slides up or down within a slot 49 of the triangular supporting structure 21.
Referring to FIG. 7 we see the corresponding section of the base 12 of the triangular structure 21 and the corresponding slot 48 and a rod 24 therein. The rod is free to pass in or out on 42 and 48 a stated distance in order to permit a much tighter pressure to be maintained on the railing which is held therein.
Referring again to FIG. 3, we see a section of ladder rail 11 within the opening and pressing against the altitude leg of triangle 21. This shows that piece 23 is free to slide to contact one side of railing 11 and that 24 can slide over such that a uniform parallel pressure with rod 22 can therefore be obtained which will prevent any rotation of the device about the railing regardless of the amount of weight that will be placed on the ladder when it is pressing up against the building.
Referring now to FIG. 5, we see in greater detail the footplate 31 and its rubber contact 32 which presses against the building. We note that screw 27 is threaded permitting the footplate to be moved up or down such that they provide independent adjustment for each device providing a greater flexibility on uneven building surfaces. Unevenness can come about by being underneath the base of one shingle while on the other side it is above the base of a shingle, or the unit is placed against the trim woodwork of a building or one side is on a raised portion and one side is on an indented portion. This alone provides a flexibility unknown in the prior art. However, a more unique feature resides in the metal plate 31 and the relative point contact that rod 27 provides. The plate becomes distorted to conform to the wall somewhat in view of the fact that it is relatively thin gauged (about 10 gauge steel which is deformable). Furthermore, 32 is shown with a sloping surface. This accommodates the angular relationship that the ladder has with reference to the flat surface 14 of the building which the ladder lines up with. However, any failure on the part of the angular surface 23 to accommodate the structure is readily made up by the point contact 27 and plate arrangement 31 of the present invention. Furthermore, the sloping structure 32 has a sponge rubber arrangement within its center which takes up further inequalities of the surface. However, sponge rubber has its failings inasmuch as abrasion can destroy it. Accordingly, the sponge rubber center has its surface coated with a more abrasive-resistant rubber surface such as silicone or neoprene rubber and the like. Once the unit has been fabricated, that is sponge rubber sloping surface 32, it is adhesively connected to the plate 31, the entire unit is dipped in silicone rubber to provide a more abrasive-resistant surface. It has been discovered that sponge rubber provides a much more uniform surface than a hard rubber surface. It is therefore advisable to replace the units more often than would be the case with hard rubber for the advantages gained by the uniform distribution of forces are very cheaply purchased by the occasional replacement of a foot plate.
Referring again to FIG. 1, another advantage of the present invention will be readily noted. Both unit 13 and 12 can be quickly loosened and they can be turned around on the rail and retightened such that 12 and 13 triangular portions will be facing inward. The ladder can then be stored with these units in place. The units being made of aluminum and being relatively small in size are lightweight providing ease in erecting and placing the unit in place against the building and so too in storage. In FIG. 3 we see that the screw rod 27 can be removed from that end and inserted in place of rod 24 at the other end such that the footplates 31 and 32 will be closely aligned with the railings of the ladder if one so chooses. Therefore, if one wished to utilize the ladder with the foot pads very close to the railings so that the ladder may be extended in between narrow areas on complicated structures particularly near the peak of a building which has an overhang from the roof, it can be easily achieved. This latter advantage is nowhere to be found in prior art devices. Another advantage inherent within the present device that may not be immediately obvious is the safety factor. As was stated earlier, the trend in ladders today is aluminum ladders which are lightweight. When the ladder is leaning up against a building a slight breeze can lift it slightly. The hard, narrow surface of the railings would then lose contact with the building. Loss of frictional contact of the ladder can cause it to fall slightly left or right. Once this is started, it is inevitable that the ladder will come crashing to the ground. With the present invention we see that we have sponge rubber 32 on footplates 31. The weight of the ladder compresses this somewhat. We further note that the triangular shape 21 causes a slight twisting of the rails of the ladder due to the weight of the ladder. With a greater weight of greater twisting force is provided. This twisting force does not affect the ladder in any adverse way. However, it does provide a certain bias. If a wind comes and lifts the ladder, it will have to lift the ladder much more than a few thousands of an inch. Under the new scheme you must lift the ladder as much as an inch to relieve all of these biases of the compressed sponge rubber and the twisting of the rails before frictional contact at the upper end of the ladder is no longer present. This is very unlikely to occur. Therefore, the present invention provides a much greater margin of safety than a conventional ladder without the use of the present invention from having the ladder come crashing to the ground. So too, when an individual is on the ladder working, he cannot lift one railing of the ladder up eliminating frictional contact and therefore walk the ladder into a position a bit to the left or to the right on the building. He must dismount from the ladder, pull it out slightly, and then move the ladder. Therefore, wreckless and negligent workers with the present attachment will be unable to cause themselves injury by such recklessness as trying to walk the top of a ladder along the building.
By making the unit into two small triangular sections that is attachable to the ladder, a significant weight reduction is achieved. These units weigh but a pound in toto. This is considerably less than any of the prior art attachments that attempt to solve some of the problems that the present invention solves--they are several pounds. Several pounds in this sort of an arrangement is very critical for if one were only to imagine that the ladder were 15 feet long, an individual could extend his arm perhaps 4 feet up the ladder and operate one end of the ladder by pulling or pushing on a 3-foot rail from fulcrum. Therefore, 15 pounds on the other end would have a 10-foot lever arm. It will be seen that 1 pound must be multiplied by the 10 feet to make a comparison. Therefore, any unit of the prior art would be useless as far as a single man being able to utilize the device. With the present invention the attachment adds very slightly to the weight. As far as a lever arm considerations, it's negligible in comparison to prior art devices. So the individual home owner who must work alone will be able to utilize this device without the assistance of someone else. It is the view of the inventor that prior art devices owing to their heavy weight and owing to the nature of the user, the home owner, they could never have been satisfactorily utilized while the present invention can and will be utilized providing that safety, convenience and inexpensiveness that the homeowner needs.
Although I have described my invention with reference to particular apparatus, it is to be clearly understood that those skilled in the art will be able to make many substitutions and variations without departing from the true scope and spirit of this invention. Accordingly, I only wish to be limited by the attached claims.
Along with the changes in ladders as to material, particularly that of aluminum, the siding on buildings has undergone dramatic changes as well. There's a great popularity in use of aluminum siding as well as vinyl shingle siding. In both instances these materials cannot support a very narrow point contact that is established by the conventional ladder without deformation of total destruction. Therefore, a significant problem with the modern siding is that of breakage or deformation as a result of the use of ladders.
The lightweight design of aluminum ladders makes for increased portability and flexibility in placing the ladder. However, coupled with the problem of destroying siding on a house is a distinct safety problem. With two small point contacts of a lightweight ladder against the building and no one on the ladder, a simple light breeze is all that is needed to lift the ladder slightly. If it is slightly ajar on the ground, (that is a small angle of inclination toward any one direction), the ladder will slide off of the building, crash to the ground, and cause severe injury to people or passerbys. This difficulty with the aluminum ladder is also present when someone is on the ladder because although the force against the building is greater, it may not be significant enough to provide enough friction with a slightly higher wind. Accordingly, the lightweight of the ladder and the small point contact present very severe problems.
Another difficulty with a ladder of conventional design is that the rails are so close to the building in the work area, that is the painter or repairman encounters some difficulty. Therefore, any scheme which would hold the latter out from the building slightly would provide a distinct advantage which would enable one to work more effectively in the area where the ladder is making contact with the building. And if the contacts were extended out from the rails any distance, the ladder would be used very effectively while working on windows because the contacts would straddle the window providing much more ease for working in such areas.
Prior art devices have been suggested to meet some of the above problems. For one thing, many designs have been made to straddle windows; however, even the straddle arrangement usually ended up in a very small point contact against the building which would only provide for the solution of one problem--that of straddling the window. Another difficulty that was not provided for, therefore, was the destruction of shingles or siding; and the safety factor of lifting the ladder slightly out from the wall by a breeze enabling it to fall to the ground. The prior art device referred to here invariably was of unitary design and extremely heavy. Therefore, users could not attach or detach the unit easily and when they attached it, they would have difficulty in placing the unit--ladder, that is--with the attachment thereto against the building owing to its great weight. The present invention was therefore devised which could straddle a window as in prior art devices but would be of exceedingly lower weight, at the same time its cost would be much lower. Its ability to be attached to a ladder significantly more easy providing decided advantages over the prior art devices especially for those with the greatest need--that of the home owner.
The greatest single advantage of the present invention is not that of straddling the window. It is, however, that of a safety factor which the present invention provides for it does not make minimal contact with a wall. It provides a considerable area of friction material which spreads itself against the wall and at the same time a flexible spring-like action of the device along with the ladder provides a bias which no single slight breeze can release permitting the ladder to slide off the building. And when a customer who has purchased the ladder is using it some several feet above the ground, he cannot rock the ladder or cause it to slide. He must disembark from the ladder and move it from the ground.
Not unlike the prior art the present invention will straddle the wall or window that may be desired to be worked on. Moreover, the present invention, which does not have a unitary design, permits one to work freely within the center of the ladder where the work is chiefly to be conducted; because of its two piece nature, it does not block or obstruct the area between the rails.
Therefore, an object of the present invention is to provide a ladder attachment having two separate units.
Another object of the present invention is to provide a two-unit (lightweight) attachment for ladders.
Another object of the present invention is to provide a two-unit ladder attachment which provides an inherent bias preventing the ladder from sliding off of the building.
Another object of the present invention is to provide a sponge-like, flexible foot for attachment to a ladder which distributes the force of the ladder in contact with the building preventing indentation or destruction of siding or shingles.
Other objects and advantages of the present invention will be better understood from the following specification when read in conjunction with the attached drawings of which:
FIG. 1 is the top of a ladder with the invention attached.
FIG. 2 is a ladder leaning against a building with the ladder attachment.
FIG. 3 is a closeup top view of a ladder attachment accorded to the present invention.
FIG. 4 is a rail support bar according to the present invention.
FIG. 5 is a foot for the ladder attachment which comes in contact with the building.
FIG. 6 is a section of the ladder attachment.
FIG. 7 is a lower portion of the ladder attachment 12.
Referring to FIG. 1 we see a ladder 11 with two identical devices in accordance with the present invention which are attached to the rails of the ladder--they are designated 12 and 13.
In FIG. 2 we see the ladder 11 against a building 14 and the attachment 13 is shown holding the ladder out from the building at a prescribed distance.
The individual units 12 and 13 when attached to the ladder obviously can span considerable distance such that they can span the distance of a window as many of the conventional prior art devices could do. However, the fact that they are two single independent units provides something rather unique. Their weight is only a fraction of the prior art devices yet it provides much more facility for working at the top of a ladder in and about the window because the center portion is no longer their obstructing one's effort particularly that of painting or repairing parts of the window.
Another advantage of the present invention in its spanning quality is with modern siding of very thin gauged steel or aluminum, it is wise to spread the forces of the ladder onto more than one shingle. With the present invention 12 and 13 may be offset from one another such that they do not line up directly on the same single or row of shingles. Furthermore, the distance apart that these units come in contact with the building are such that a greater distribution of force is achieved which also prevents the shingle from being injured. As we will see further, the present invention makes other provisions which prevents injury to siding.
Referring to FIG. 3 we see an individual unit in much greater detail. 12 as shown has a triangular reinforcement structure, 21. Within the box-like structure formed by the altitude leg of the triangular structure, a movable piece 23, rod 24, and that portion which is an extension of the base of the triangle is utilized to enclose the railing of the ladder. It is placed over a ladder rail and rod 24 is pushed in as close as possible within track 48 and track 42 then thumb screw 25 is turned until 23 presses against the ladder rail 11. Thumb screw 6 is then tightened on screw 22 so that symmetrical force provides a secure contact to the ladder rail. Another identical attachment can be attached to the other railing as 13 but flipped over. Each unit is identical and will be attached in the same manner. Screw 27 is about a foot out from the edge of the ladder railing and has a foot plate 31 attached to the screw and compressible rubber material 32 attached to the foot plate. Two thumb screws 28 and 29 enable it to be positioned in or out from the ladder rail so that a symmetrical or unsymmetrical position can be attained about the ladder so that flat surfaces of buildings and sloping surfaces can be equally accommodated.
Referring to FIG. 4 we see piece 23 which comes in contact with a portion of ladder rail. 23 has a hole 41 for screw 22 which can be tightened to maintain a pressure on the rail. So too, can 24 be tightened with a thumb screw 25; however, in this event slot 42 permits rod 24 to slide in or out such that a closer control over the pressure on the railing is provided. Furthermore, notches 46 and 47 permit the piece 23 to slide up and down freely in slot 49 yet be unable to slip out of triangular member 21.
Referring to FIG. 6 we see an end view of 23 as it slides up or down within a slot 49 of the triangular supporting structure 21.
Referring to FIG. 7 we see the corresponding section of the base 12 of the triangular structure 21 and the corresponding slot 48 and a rod 24 therein. The rod is free to pass in or out on 42 and 48 a stated distance in order to permit a much tighter pressure to be maintained on the railing which is held therein.
Referring again to FIG. 3, we see a section of ladder rail 11 within the opening and pressing against the altitude leg of triangle 21. This shows that piece 23 is free to slide to contact one side of railing 11 and that 24 can slide over such that a uniform parallel pressure with rod 22 can therefore be obtained which will prevent any rotation of the device about the railing regardless of the amount of weight that will be placed on the ladder when it is pressing up against the building.
Referring now to FIG. 5, we see in greater detail the footplate 31 and its rubber contact 32 which presses against the building. We note that screw 27 is threaded permitting the footplate to be moved up or down such that they provide independent adjustment for each device providing a greater flexibility on uneven building surfaces. Unevenness can come about by being underneath the base of one shingle while on the other side it is above the base of a shingle, or the unit is placed against the trim woodwork of a building or one side is on a raised portion and one side is on an indented portion. This alone provides a flexibility unknown in the prior art. However, a more unique feature resides in the metal plate 31 and the relative point contact that rod 27 provides. The plate becomes distorted to conform to the wall somewhat in view of the fact that it is relatively thin gauged (about 10 gauge steel which is deformable). Furthermore, 32 is shown with a sloping surface. This accommodates the angular relationship that the ladder has with reference to the flat surface 14 of the building which the ladder lines up with. However, any failure on the part of the angular surface 23 to accommodate the structure is readily made up by the point contact 27 and plate arrangement 31 of the present invention. Furthermore, the sloping structure 32 has a sponge rubber arrangement within its center which takes up further inequalities of the surface. However, sponge rubber has its failings inasmuch as abrasion can destroy it. Accordingly, the sponge rubber center has its surface coated with a more abrasive-resistant rubber surface such as silicone or neoprene rubber and the like. Once the unit has been fabricated, that is sponge rubber sloping surface 32, it is adhesively connected to the plate 31, the entire unit is dipped in silicone rubber to provide a more abrasive-resistant surface. It has been discovered that sponge rubber provides a much more uniform surface than a hard rubber surface. It is therefore advisable to replace the units more often than would be the case with hard rubber for the advantages gained by the uniform distribution of forces are very cheaply purchased by the occasional replacement of a foot plate.
Referring again to FIG. 1, another advantage of the present invention will be readily noted. Both unit 13 and 12 can be quickly loosened and they can be turned around on the rail and retightened such that 12 and 13 triangular portions will be facing inward. The ladder can then be stored with these units in place. The units being made of aluminum and being relatively small in size are lightweight providing ease in erecting and placing the unit in place against the building and so too in storage. In FIG. 3 we see that the screw rod 27 can be removed from that end and inserted in place of rod 24 at the other end such that the footplates 31 and 32 will be closely aligned with the railings of the ladder if one so chooses. Therefore, if one wished to utilize the ladder with the foot pads very close to the railings so that the ladder may be extended in between narrow areas on complicated structures particularly near the peak of a building which has an overhang from the roof, it can be easily achieved. This latter advantage is nowhere to be found in prior art devices. Another advantage inherent within the present device that may not be immediately obvious is the safety factor. As was stated earlier, the trend in ladders today is aluminum ladders which are lightweight. When the ladder is leaning up against a building a slight breeze can lift it slightly. The hard, narrow surface of the railings would then lose contact with the building. Loss of frictional contact of the ladder can cause it to fall slightly left or right. Once this is started, it is inevitable that the ladder will come crashing to the ground. With the present invention we see that we have sponge rubber 32 on footplates 31. The weight of the ladder compresses this somewhat. We further note that the triangular shape 21 causes a slight twisting of the rails of the ladder due to the weight of the ladder. With a greater weight of greater twisting force is provided. This twisting force does not affect the ladder in any adverse way. However, it does provide a certain bias. If a wind comes and lifts the ladder, it will have to lift the ladder much more than a few thousands of an inch. Under the new scheme you must lift the ladder as much as an inch to relieve all of these biases of the compressed sponge rubber and the twisting of the rails before frictional contact at the upper end of the ladder is no longer present. This is very unlikely to occur. Therefore, the present invention provides a much greater margin of safety than a conventional ladder without the use of the present invention from having the ladder come crashing to the ground. So too, when an individual is on the ladder working, he cannot lift one railing of the ladder up eliminating frictional contact and therefore walk the ladder into a position a bit to the left or to the right on the building. He must dismount from the ladder, pull it out slightly, and then move the ladder. Therefore, wreckless and negligent workers with the present attachment will be unable to cause themselves injury by such recklessness as trying to walk the top of a ladder along the building.
By making the unit into two small triangular sections that is attachable to the ladder, a significant weight reduction is achieved. These units weigh but a pound in toto. This is considerably less than any of the prior art attachments that attempt to solve some of the problems that the present invention solves--they are several pounds. Several pounds in this sort of an arrangement is very critical for if one were only to imagine that the ladder were 15 feet long, an individual could extend his arm perhaps 4 feet up the ladder and operate one end of the ladder by pulling or pushing on a 3-foot rail from fulcrum. Therefore, 15 pounds on the other end would have a 10-foot lever arm. It will be seen that 1 pound must be multiplied by the 10 feet to make a comparison. Therefore, any unit of the prior art would be useless as far as a single man being able to utilize the device. With the present invention the attachment adds very slightly to the weight. As far as a lever arm considerations, it's negligible in comparison to prior art devices. So the individual home owner who must work alone will be able to utilize this device without the assistance of someone else. It is the view of the inventor that prior art devices owing to their heavy weight and owing to the nature of the user, the home owner, they could never have been satisfactorily utilized while the present invention can and will be utilized providing that safety, convenience and inexpensiveness that the homeowner needs.
Although I have described my invention with reference to particular apparatus, it is to be clearly understood that those skilled in the art will be able to make many substitutions and variations without departing from the true scope and spirit of this invention. Accordingly, I only wish to be limited by the attached claims.