US 3318413 A
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Description (OCR text may contain errors)
y 9, 1967 R. L. WERNER ETAL 3,318,413
LADDER JOINT CONSTRUCTION Filed Oct. 23, 1965 United States Patent 3,318,413 LADDER JOINT CONSTRUCTION Richard L. Werner, Sharon, Pa., and Lawrence A. Kocina, Simsbury, Conn., assignors to R. D. Werner Co., Inc., Greenville, Pan, a corporation of Pennsylvania Filed Oct. 23, 1565, Ser. No. 502,954 10 Claims. (Cl. 182-46) This invention relates to ladders and relates more particularly to improvements in joint constructions therefor and an improved method of assembling ladders thereby.
The improvement in this invention particularly resides in an improved ferrule for use in joints for ladders, which ladders are constructed with tubular side rails of metal or fiber glass or like material, said ferrule securely fastening rungs of fiber glass, plastic or other synthetic material, or metal to said side rails.
An object of our invention is to provide a ladder of novel construction in which the spaced lightweight metal or fiber glass side rails may be connected by rungs of fiber glass or other lightweight material in a secure manner and without danger of fracture or weakening of either the rails or the rungs in assembly or in use.
A further object of our invention is to provide an improved ladder joint construction and method of manufacture for ladders of the type referred to.
A still further object of our invention is to provide an improved ladder rail and rung assembly.
Yet another object of our invention is to provide an improved joint construction for use in ladder rail and rung assemblies which resists high axial loads and produces high torque capacity for the joint.
Other objects of our invention and the invention itself will become more readily apparent from a preview of the appended description and the accompanying drawings, in which drawings:
FIGURE 1 is a plan view of the improved ferrule of this invention, certain portions being shown in dotted lines to disclose the two-part construction thereof;
FIGURE 2 is a side view of one of said two parts of the ferrule of FIGURE 1, certain parts being shown in dotted lines for greater clarity;
FIGURE 3 is a view similar to FIGURE 2 of the other of said two parts of the ferrule of FIGURE 1;
FIGURE 4 is a top view of the ferrule part of FIG- URE 2;
FIGURE 5 is a top view of the ferrule part of FIG- URE 3;
FIGURE 6 is a view of the tubular metal or fiber glass side rail with dotted lines depicting holes in webs required to receive the ferrule;
FIGURE 7 is a sectional view of the ferrule of FIG- URE 1 in assembled relation with a fiber glass rung and fiber glass tubular rail member of a ladder.
To produce the completed joint assembly shown in FIGURE 7 tubular side rails 10 of metal, molded fiber glass, plastic or other synthetic material, are first formed preferably of rectangular box-like form having parallel spaced sides 11 and 12, and said sides are provided with aligned rung openings 13 and 14, the opening 14 being in the form shown of relatively greater diameter than the opening 13 opposite the same. As shown herein the rung openings 13 and 14 are preferably circular in form and receive the circular ferrule members 15 and 16 respectively, and circular rungs 17 therein. It is contemplated that the form of said rungs, rung openings and ferrule members may be varied; as for example, be of oval form, if desired, without departing from the invention herein shown, described and claimed. The rung illustrated herein is preferably tubular and of fiber glass material although other lightweight materials as specified hereinbefore could be utilized.
3 318,4 1 3 Patented May 9, 1 967 in our co-pending application Ser. No. 571,249, filed Aug.
9, 1966. Said annuli 18 and 19 are adapted when the ferrule parts are assembled with the rung and rail to abut portions of the rail surrounding the rung opening through which the respective ferrule parts are inserted.
The ferrule member 15 as shown is of substantially cylindrical form, the interior of the same being separated into two parts 20, 21 of different inner diameter, the portion 20 underlying the annuli 18, 19 and portions adjacent thereto, being of relatively less inner diameter than the end portion 21 extending therefrom. A shoulder 22 is thus provided between said portions or sections 20, 21 of the ferrule and said shoulder 22 is preferably curved inwardly upwardly from the portion 21 toward the merging portion 20 of the ferrule member 15.
' The second ferrule member 16, as shown and in the form illustrated in the figures herein, is cylindrical in form; the interior of the same is preferably constant diameter throughout, its outer diameter being substantially the same diameter as the inner diameter of the portion 21 of the first ferrule 15.
It is to be noted that in assembling the rail and rung, and in the form illustrated, the rung is cylindrical in form, the ferrule 15 having the preformed annuli 18 and 19 thereon are preferably press fitted over the rung 17 and an end portion 24 of said rung 17 extends outwardly thereof a short distance, the rung 17 and its associated ferrule 15 is then projected into the relatively larger rung opening 14 in the side wall 11 of the tubular rail. The ferrule part 15 is of such length that when the preformed annulus 18 abuts the outer surfaces of the wall 11 of the ladder side rail surrounding the opening 14, the outer edge 25 of the said ferrule part 15 is stopped by and abuts the inner wall surfaces of the opposite side wall 12 of the tubular rail 10 surrounding the opening 13 therein. Clearance 26 is provided between the portion 21 of the ferrule 15 and the rung 17 into which the body portion 16' of the sleeve or ferrule 16 is projected; the ferrule 16 is provided with a curved inner edge 27 and rides upon the shoulder 22. The ferrule 16 being preferably of slightly greater length than the portion 21 of the ferrule 15 into which it is press fitted, further driving force on the ferrule 16 distorts underlying portions of the rung 17 as shown at 27 and key the ferrule parts 15, 16 to the rung.
In the event further security is desired between the ferrule parts, a plurality of longitudinal grooves 28 may be provided interi-orly of the ferrule 15 and exteriorly as at 29 of the body portion 16 of the ferrule 16 in which adhesive material, such as an epoxy, may be injected. The grooves are adapted to communicate, as shown.
The improved construction of this invention will, it will be noted, suitably provide a stress and strain resistant ladder joint, with reinforcing means provided therefor to structurally strengthen those portions of the tubular side rails adjacent the rung openings, which, in the case of fiber glass ladders, is of particular importance. The rungs may be of aluminum, fiber glass, or other material, corrugated or uncorrugated, and the ferrules of aluminum or other lightweight material.
In the event the rungs are flat, rectangular, square, oval, or of other form as described, it will be understood that the openings and ferrules will be suitably formed.
We are aware that numerous and extensive departures may be made, such as size and shape, without departing however from the spirit of our invention or the scope of the appended claims.
What we claim is: I
1. A joint for a tubular ladder rail having aligned openings in spaced rail sides thereof, one of said openings beingof relatively greater diameter than said substantially opposite opening, a rung, a two-part ferrule telescoped over an end portion of said rung, said two-part ferrule comprising a first tubular member having an enlarged peripheral flange at one end projecting radially outwardly thereof, said first member having a portionrtelescoped over an end portion of a said rung in engagement therewith and a second portion telescoped over the end portion of said rung inspace'd relation thereto, the said ferrule and rung assembly projecting through the said relatively greater diameter opening in one of said rail sides, the said ferrule flange abutting portions of the rail sides surrounding said larger diameter opening and an end of said first tubular member abutting inner wall surfaces of the rail side surrounding the opening of relatively lesser diameter in said opposite rail side, said second tubular member having a portion projecting through said opening of lesser diameter and occupying the space between the second portion of said first member and the rung end portion, and having a peripheral flange at one end projecting radially outwardly thereof in abutting engagement with the outer wall surfaces of the rail side surrounding the opening of lesser diameter.
2. A joint for tubular ladders as claimed in claim 1 in which said first tubular member comprises a tubular body portion of uniform outer diameter for round rungs or equivalent dimension for non-round rungs and of variant inner diameter for round rungs or equivalent dimensions for non-round rungs.
3. A joint for tubular ladders as claimed in claim 1 wherein the portion of the second tubular member projected into the space between the first tubular member and a rung end portion has an end portion which is distorted and distorts underlying portions of the rung to key the two ferrule parts to the rung.
4. A joint for tubular ladders as claimed in claim 1 in which the first tubular ferrule is provided with a plurality of grooves and the second ferrule member is provided with a plurality of grooves, binding material being disposed within said grooves to secure said ferrule parts.
5. A joint for tubular ladders as claimed in claim 1 in which the rail sides and rungs are formed of metal.
6. A joint for tubular ladders as claimed in claim 1 in which the rail sides and rungs are formed of fiber glass.
7. A joint for tubular ladders as claimed in claim 1 in which the rail sides and rungs are formed of plastic or other synthetic materials 8. A joint for tubular ladders as claimed in claim 1 in which the rail sides are formed of metal.
9. A joint for tubular ladders as claimed in claim 1 in which the rail sides are formed of fiber glass.
10. A joint for tubular ladders as claimed in claim 1 in which the rail sides are formed of plastic or other synthetic materials.
References Cited by the Examiner UNITED STATES PATENTS 1,195,482 8/1916 Lewis 287-5207 3,115,539 12/1963 Stuessel et a1. 285-158 3,208,554 9/1965 Arnold 182-46 REINALDO P. MACHADO, Primary Examiner.