US3208554A

US3208554A - Rung and side rail connection for ladders

Info

Publication number: US3208554A
Application number: US327229A
Authority: US
Inventors: Harold G Arnold
Original assignee: BAUER Manufacturing CO
Current assignee: BAUER Manufacturing CO
Priority date: 1963-12-02
Filing date: 1963-12-02
Publication date: 1965-09-28
Anticipated expiration: 1982-09-28

Description

Sept. 28, 1965 H. s. ARNOLD HUNG AND SIDE RAIL CONNECTION FOR LADDERS Filed Dec. 2, 1963 INVENTOR. HAROLD G. ARNOLD AT T YS.

United States Patent 3,208,554 RUNG AND SIDE RAIL CONNECTION FOR LADDERS Harold G. Arnold, Wooster, Ohio, assignor to The Bauer Manufacturing Company,

6 Claims. (Cl. 182-46) This invent-ion relates to ladders having hollow side rails made of impregnated fiberglass and means for attaching rungs thereto, particularly whereby the attachment is made without deforming either the rung or the side rail.

This application is an improvement to my co-pending patent application Serial No. 153,985 on Rung and Side Rail Connect-ion for Ladders filed on November 21, 1961, and now abandoned. These applications have been filed because in recent years conventional wooden ladders have, to at least some extent, been replaced with ladders having portions thereof, and usually side rails, made of aluminum or its alloys. Ladders of this type are often more durable and stronger than wooden ladders, but are open to the objection that they will conduct electricity which is undesirable in many uses of a ladder. Further, fiberglass can provide even greater durability and strength than aluminum.

Therefore, it is the general object of the invention to avoid and overcome the foregoing and other difiiculties of and objections to prior art practices by the provisions of a ladder in which the side rails are made of hollow, resin impregnated fiberglass, and which is characterized by simplicity of construction, lightweight and high strength in use, and a long and maintenance-free life.

Amother object of the invention is to provide a ladder having hollow resin impregnated fiberglass side rails oined together with a plurality of rungs the ends of which abut against the side rails and which are held in position there-against by bolt means engaging sleeves which engage the outer surface of the fiberglass side rail with the thrust of the bolt being taken against spools positioned around the bolt means inside of each side rail. The aforesaid objects of the invention, and other obects which will become apparent as the description proceeds, are achieved by the combination in a ladder of a pair of hollow fiberglass side rails, a plurality of sleeves having one enlarged end slidably positioned through opposed holes in the side rails at equally spaced distances so that enlarged ends abut one side of the side rails and the other ends protrude from the othre side thereof, fiberglass rung means adapted to be slidably positioned over the protruding ends of the sleeves between the side rails, support means inside the side rails adapted to support the area adajacent to the opposed holes, and means to operatively engage the rungs to their respective sleeves.

For a better understanding of the invention reference should be had to the accompanying drawings, wherein:

FIGURE 1 is a front elevation, partly broken away, of a ladder construction incorporating the principles of the invention; and

FIGURE 2 is a slightly enlarged cross-sectional view taken substantially on line 22 of FIGURE 1.

In the drawings, the numeral 10 indicates generally a ladder having a pair of side rails 12 made of resin-impregnated fiberglass and having a hollow elliptical shape in cross section, as more particularly seen in FIGURE 2. Each side rail 12 has a hollow substantially elliptical shape in cross section to provide a structural relationship which is light in weight but of very high strength. The substantially elliptical shape of each side rail provides opposed side wall portions 14 which are essentially parallel, and which are formed with opposed openings 16,

Patented Sept. 28, 1965 usually circular, to slidably receive the ends of sleeves, indicated generally by numeral 18. The sleeves 18 have an enlarged head portion 20 adapted to abut against the outer side wall 14 and an extended end portion 22 which is adapted to protrude substantially normal to the side rail 12 a distance equal to at least the thickness of the side rail 12. The sleeves 18 also contain a longitudinally axially aligned hole 24 adapted to receive a bolt 26 to hold the sleeves 18 in position, as will be more fully described hereinafter. Further, in order to protect and strengthen the enlarged end 20 and the hole 24, each sleeve 18 may have a strengthening metal collar 28 integrally formed therewith during the molding operation.

The protruding ends 22 of the sleeves 18 are adapted to slidably receive the ends of rungs 30. The rungs 30 are normally made of hollow relatively thin-walled fiberglass or plastic tubing with the sleeves 18 being equally spaced vertically on the side rails 12 so that the rungs 18 lie in substantially horizontal parallel relationship to each other in the normal ladder configuration. The open ends of the rungs 31 are adapted to abut against the outer surface of the inner side wall 14. It is contemplated that the bolt 26 will extend axially through the rungs 30 to a similar sleeve rung combination on the opposite side rail so that a nut (not shown) can be tightened on the end to draw the opposed sleeves 18 towards each other forcing the rungs 30 into the side walls 14 and providing a very secure rung side wall combintion.

In order to prevent dishing or bending of the side walls 14 when the bolt 26 is tightened, as described above, a spool-like member 32 is provided to surround the end of each sleeve 18 inside of each side rail 12. The spool-like member 24 is usually of metal and formed with flanges 34 which engage the inside surfaces of the side walls 14 of the side rail 12. Thus, the force of the screw 26 being tightened which urges the sleeves 18 towards each other is taken up by the spool-lik member 24 to insure a firm seating of the rungs 30 to provide a particularly strong and rigid construction, all without dishing inwardly the side walls 14 of the side rails 12.

Thus, it is seen that the entire outward construction of the ladder is fiberglass or plastic to prevent any possible electric conduction or to prevent rusting and metal deterioration. A plastic plug 40 may be positioned over the head of the bolt 26 to insure that this metal surface is insulated and protected. The invention further contemplates that epoxy cement or other suitable adhesive might be used between the extended portion 22 of the sleeve 18 and the ladder rung 30 and vfurther between the enlarged head 20 of the sleeve 18 and the outside of the side wall 14 to more securely position the assembled combination.

The invention further contemplates that the spool-like member 32 may be made of rigid reinforced plastic with a greater thickness or that other reinforcing means he provided for the area adjacent the holes 16. Further, nut means could be operatively carried by the rungs 30 so that the bolts 26 might be screwed thereinto to properly seat the rung 3t and the sleeve 18 into position, rat-her than having the bolt 26 extend completely through the rung. However, with the bolt 26 extending through the rung a safety feature is provided since this bolt will provide a backup if the rung 30 breaks because of excessive pressure.

One of the problems encountered in a ladder construction of the type described above is positioning the spoollike members 32 in'the side rails 12 so they are aligned with their respective opposed openings 16. Various means are available to achieve the positioning of the spool-like members 32 such as utilizing a notched steel beam having movable fingers holding the spool-like members in the notches with the beam being inserted inside the hollow side rail to properly position the spool-like members, After the spool-like members are positioned, the fingers would be releasable allowing the beam to be withdrawn from the side rail. Another approach would be to place the spool-like members in their properly spaced relationship on an adhesive masking tape which had been previously punched. The adhesive surface of the tape would hold the spools in place, and the tape could be pulled into the side rail to the required length to properly position the spool-like members. The masking tape would be left in the side rails permanently after the rungs were positioned in combination with the side rail. One more approach might be to mount the spoollike members on a cardboard strip at the same equally spaced distances as the rungs so that the cardboard strip could be pulled inside the side rails to position the spoollike members and then remain inside the side rail after assembly of the rungs to complete the ladder. Thus, it is seen that the problem of placing the spool-like members in proper position inside the side rails is overcome.

While in accordance with the Patent Statutes only one best known embodiment of the invention has been illustrated and described in detail, it is to be particularly understood that the invention is not limited thereto or thereby, but that the inventive scope is defined in the appended claims.

What is claimed is:

1. In a ladder the combination of a pair of fiberglass side rails, said rails having a hollow cross section providing side walls having substantially parallel opposed portions,

a plurality of hollow substantially cylindrical fiberglass rungs having open ends operatively positioned between the side rails and substantially aligned with opposed openings in the side walls of the rails,

a plurality of sleeves each having one enlarged end slidably received in close spaced relationship through said opposed openings and into the open ends of said rungs so that said enlarged ends engage the outer surface of said side rails opposite to said rungs,

a spool slidably received on said sleeves inside each side rail and engaging the inside surface of the side walls of each side rail, and

bolt means operatively received through and adapted to engage opposing sleeves, and passing longitudinally through the operatively positioned rung to bias said sleeves together and hold the rungs in position on the side rails.

2. In a ladder the combination of a pair of hollow side rails having opposed side walls,

a plurality of sleeves each having one enlarged end slidably received in close fitting relation through opposed openings in said side rails so that the enlarged ends abut against one side of the side rails and the other end protrudes a distance from the opposite side thereof,

a plurality of hollow rungs with opened ends slidably positioned over the protruding ends of said sleeves between said side rails and abutting against the opposed opposite sides thereof,

collar means slidably positioned over said sleeve means inside said side rails and adapted to engage the inside surfaces of said side walls, and

tie rod means extending through each rung to connect opposed sleeves supporting the rung.

3. In a ladder the combination of a pair of hollow fiberglass side rails having opposed walls,

a plurality of sleeves made from a hard plastic material each having a continuous uniform cylindrical shape and one enlarged end reinforced with a metallic insert, said sleeves slidably received in close spaced relationship through opposed openings in said side rails so that the enlarged ends abut against one side of the side rails and the other end protrudes a distance from the opposite side,

a plurality of hollow fiberglass rungs with opened ends between said side rails positioned slidably in close spaced relationship over the protruding ends of said sleeves to about the inner sides of the side rails, and

bolt means to operatively position the sleeves in pressured relationship toward each other to hold the rungs firmly in position adjacent the side walls of said side rails.

4. In a ladder, hollow side rails each having opposed parallel Walls, hollow rungs extending between and abutting the inner sides of the side rails, a collar positioned between the parallel walls of each side rail in a position where the axes of the collar and the associated rung are coincident and the ends of the collar bear against the opposed parallel walls of the side rails, means having a continuous uniform cylindrical shape extending through aligned holes in each side rail and into the end of each rung adjacent the side rail, a shoulder on the outer end of the last-named means, and means pressing the shoulder against one wall of the side rail, pressing the rung against the other wall of the side rail, and pressing the walls of the side rail against the ends of the collar.

5. In a ladder the combination of a pair of hollow fiberglass side rails,

a plurality of sleeves having one enlarged end and the remaining length of a continuous uniform cylindrical shape slidably positioned through opposed holes in said side rails at equally spaced distances so that said enlarged ends abut one side of the side rails and the other ends protrude from the other side,

fiberglass rung means adapted to be positioned between said side rails slidably in close fitting relationship over said protruding ends of said equally spaced sleeves to abut the inner sides of the side rails,

support means inside the side rails adapted to support the area adjacent to said opposed holes, and

bolt means adapted to operatively engage the sleeves supporting opposite ends of each rung to urge them together to hold the ends of the rungs in pressured adjacent relationship with respect to the side rails.

6. In a ladder the combination of a pair of hollow fiberglass side rails having opposed side walls,

a plurality of sleeves each having an enlarged head at one end, and the remaining length of a continuous uniform cross sectional cylindrical shape, said sleeves slidably received through opposed openings in said side rails so that the enlarged heads abut against the outside of one side wall of the side rails and the other end protrudes outwardly from the other side of the side rails,

a plurality of hollow fiberglass rungs with opened ends positioned between said side rails slidably in close spaced relationship over the protruding ends of said sleeves to abut against the inner sides of the side walls, and

means to bias opposed sleeves supporting each rung towards each other.

References Cited by the Examiner UNITED STATES PATENTS 1,136,010 4/15 Hendricks et al 182-216 3,008,552 11/61 Cushman et al. 182228 3,101,205 8/63 Benharn 2 87-2O FOREIGN PATENTS 1,036,119 4/53 France.

657,746 9/51 Great Britain. 870,536 6/ 61 Great Britain.

HARRISON R. MOSELEY, Primary Examiner.

REINALDO P. MACHADO, Examiner.

Claims

5. IN A LADDER THE COMBINATION OF A PAIR OF HOLLOW FIBERGLASS SIDE RAILS, A PLURALITY OF SLEEVES HAVING ONE ENLARGED END AND THE REMAINING LENGTH OF A CONTINUOUS UNIFORM CYLINDRICAL SHAPED SLIDABLY POSITIONED THROUGH OPPOSED HOLES IN SAID SIDE RAILS AT EQUALLY SPACED DISTANCES SO THAT SAID ENLARGED ENDS ABUT ONE SIDE OF THE SIDE RAILS AND THE OTHER ENDS PROTRUDE FROM THE OTHER SIDE, FIBERGLASS RUNG MEANS ADAPTED TO BE POSITIONED BETWEEN SAID SIDE RAILS SLIDABLY IN CLOSE FITTING REALTIONSHIP OVER SAID PROTRUDING ENDS OF SAID EQUALLY SPACED SLEEVES TO ABUT THE INNER SIDES OF THE SIDE RAILS, SUPPORT MEANS INSIDE THE SIDE RAILS ADAPTED TO SUPPORT THE AREA ADJACENT TO SAID OPPOSED HOLES, AND BOLT MEANS ADAPTED TO OPERATIVELY ENGAGE THE SLEEVES SUPPORTING OPPOSITE ENDS OF EACH RUNG TO URGE THEM TOGETHER TO HOLD THE ENDS OF THE RUNGS IN PRESSURED ADJACENT RELATIONSHIP WITH RESPECT TO THE SIDE RAILS.