US3327385A

US3327385A - Method of making ladders

Info

Publication number: US3327385A
Application number: US422670A
Authority: US
Inventors: Raymond H Shaver
Original assignee: Harsco Corp
Current assignee: Enviri Corp
Priority date: 1963-01-04
Filing date: 1964-12-31
Publication date: 1967-06-27
Anticipated expiration: 1984-06-27

Description

3mm 1957 R. H. SHAVER 332 9 METHOD OF MAKING LADDERS Original Filed Jan. 4, 1963 2 Sheets-Sheet 1 A 77mm rs June 27, 1967 R. H. SHAVER METHOD OF MAKING LADDERS 2 Sheets-Sheet Original Filed Jan.

ATTORNEYS United States Patent 3,327,385 METHOD OF MAKING LADDERS Raymond H. Shaver, Newark Valiey, N.Y., assignor, by

mesne assignments, to Harsco Corporation, a corporation of Delaware Original appiication Jan. 4, 1963, Ser. No. 249,470, now Patent No. 3,168,938, dated Feb. 9, 1965. Divided and this application Dec. 31, 1964, Ser. No. 422,670

14- Claims. ((31. 29-512) The present invention relates to a method of making ladders; and this application is a division of my co-pending application, Ser. No. 249,470, filed Jan. 4, 1963, issued Feb. 9, 1965 as No. 3,168,938.

Ladders of traditional types and materials have, for many purposes, been too heavy if made sufficiently strong; or, if made of lighter weight materials, have lacked necessary strength or durability. It has not been feasible merely to substitute in known structures a lighter material, as fiberglass, plastic or aluminum in place of wood or heavier metals because, for some applications in use, the ladder structure is thus materially weakened.

An object of the present invention has therefore been to provide a method of making a ladder of novel construction which permits the use of light weight materials with no consequent undesirable weakening or lack of durability. Further, it is contemplated that ladders made by the method embodying this invention may be made at reasonable cost from relatively light weight materials which are in abundant supply and may be transported at favorably moderate rates because of their weight and sturdy construction.

In general, a ladder made according to the method of the present invention comprises side rails which may be open channels, or which may be of the box type, i.e., tubular members of light weight material, assembled with tubular rungs of light weight malleable metal, as aluminum or an appropriate alloy thereof, with the rung ends rigidly engaged in web portions of said side rails.

In constructing such a ladder, the opposed side rail webs are provided with coaxial holes; and the rungs are deformed to produce thereon peripheral beads spaced from their ends. These rails and rungs are assembled with the rung ends engaged in said holes and with the beads bearing against portions of the webs which surround the edges of said holes. Each thus engaged end of said rungs is swaged, crimped, expanded or otherwise deformed to provide an end flange which, with said bead, serves to clamp the adjacent rung end securely to the side rail. In assembling rungs with box type rails, i.e., of tubular cross sectional contour, an interior spacer is positioned prior to said deformation to embrace that portion of each rung end which lies within and extends between the opposed walls of the rail; and in some instances, said spacer is deformed at least in part along with deformation of the rung end.

Other objects and important features of the invention not above referred to will appear in the following description and claims and from the accompanying drawings wherein I have shown a preferred embodiment of the invention and have described the same in this specification. It is to be understood that these disclosures are not intended to be either exhaustive or limiting of the invention, but on the contrary, are presented for the purposes of illustration so that others skilled in the art may so fully understand the same, its principles and the application thereof, that they may embody it and adapt it in various forms each as may be appropriate to the requirements of a particular purpose in use.

Referring to the drawings:

FIGURE 1 is a fragmentary view partly in section showing a portion of a box type or tubular ladder side Patented June 2?, 1967 rail, an end portion of a rung engaged therewith, and a tubular spacer in process of being moved into position on the end of said rung;

FIGURE 2 is a fragmentary view partly in section of the parts shown in FIGURE 1 after the rung end and the spacer have been deformed to modified contours, as by swaging, crimping or the like;

FIGURE 3 is a modification wherein the box type side rail is employed. The parts are here shown with one end wall member not yet assembled with the side walls to permit placing of the spacers on the rung ends between said side walls, the parts being shown with the spacer coaxially arranged in relation to opposed coaxial openings in the side walls of the rail and with the rung end in process of being moved into operative position in said spacer and said holes;

FIGURE 4 is a fragmentary view of the parts seen in FIGURE 3 after the rung end has been deformed to clamp the spacer in wall reinforcing position in the side rail; and the end wall has been applied to close the end opening between said side walls.

FIGURE 5 is a modification partly in longitudinal section showing the step of moving a spacer into coaxial relation to opposed holes in a box type rail having a continuous unitary tubular wall open at its top and bottom ends, by means of a pusher actuated from one of said ends; and

FIGURE 6 is a fragmentary view partly in section of an open type channel side rail with a rung end crimped to form a bead and an end flange in clamping engagement with the peripheral edge of a hole or opening in the channel web.

To produce the completed ladder structure shown in FIGURE 2, I provide the webs a and b of opposed side rails, as the unitary tubular box type rail 10, FIGURE 1, with opposed coaxial holes, one of which, as 11 in web a is of smaller diameter than the other, as 12 in web b. A bead 13 is formed, as by crimping, near the end of tubular rung 14 which may advantageously be of malleable metal, such as aluminum or aluminum alloy; and said side rails may be of suitable light weight but strong material as fiberglass, aluminum, etc. This end of said rung beyond the bead 13 is moved in the direction of the arrow at the right, FIGURE 1, through openings 11 and 12 to bring head 13 snugly against the outside face of web a; and spacer 15 may be moved through opening 12 in the opposite direction, i.e., that of the arrow at the left, FIGURE 1, either along with the entering movement of the rung end or after said end has reached the position shown in FIGURE 1. Or, where rung 14, prior to assembly, has no abutment or bead 13 adjacent its ends, the end portion is engaged in the laterally spaced opposed openings 11 and 12 in the inner and outer walls, a and b, respectively, of the rail and with a spacer 15 embracing said end between said walls. Bead 13 and flange 18, for example, may now be formed against said rail walls by securing rung 14 against endwise displacement while pressing, hammering or otherwise deforming said end portions to produce the desired abutments or beads while said spacer 15 prevents collapse of the rung end between the walls of the rail. In either case. when spacer 15 reaches the dotted line position shown in said figure, known mechanical devices and procedures are employed to expand the rung end and said spacer 15 to suitable outwardly flared contours, FIG- URE 2. This expansion effected by pressure forging, for example, along with spinning, swaging, or the like, drives the flared portion of the rung end into secure engagement with the edge of opening 12 which is advantageously interrupted by a notch 16. A portion of the displaced metal of said rung end effected by said forging, or the like, flows into said notch 16 to form a key 17, thus, in effect, locking the rung 14 against rotation. Deformation of the rung end also produces a terminal flange, 18, FIGURE 2, which, with head 13, serves to clamp rung 14 securely in operative relation to rail 10.

The deforming or crimping operations just above referred to involve application of substantial axial pressures. It is therefore contemplated that the rail walls will be materially reinforced to withstand said pressures by providing the spacer 15 of suitable material and dimensions. When placed as seen in FIGURE 1 (dotted) said spacer prevents collapse of the rail Walls under pressure while permitting deforming or metal flowing forces to operate effectively and thereby produce the joint structure of FIGURE 2.

It is apparent that spacer 15 in the deformed condition seen in FIGURE 2 and cooperating with bead 13 and flange 18 also permits rung 14 to be clamped securely to both webs of rail 10 and counteracts any weakening effect of the holes 11, 12 therein.

A modified form of structure as seen in FIGURE 4 also employs a box type side rail 20 which, instead of being a unitary tube, as in FIGURE 2, is a composite tube comprising spaced

webs

21 and 22 and end or

edge channels

23, 24. Said webs are provided with opposed

coaxial holes

25 and 26 of the same diameter which is also approximately that of the outside diameter of rungs 14, the periphery of said holes being interrupted by one or more notches 27 therein. The structure as seen in FIGURE 4 may conveniently be produced by a method as illustrated in FIGURE 3.

Accordingly, side rail 20 is partly assembled by engaging

Webs

21 and 22 with end channel 24. By not connecting end channel 23. at this phase, one end of the rail (upper FIGURE 3) is left open. Spacer 28 is inserted through said opening in the down direction of the arrow FIGURE 3, to a position wherein it is coaxial or in register with the

holes

25, 26.

While said spacer is in this position, the end of rung 14 is moved in the direction (left) of the arrow, FIGURE 3, through opening 25, through the spacer 28 and through opening 26 to an extent which brings head 13 snugly against the outside face of web 21 and brings the end of rung 14 beyond the outside face of web 22. Thus, spacer 28 is positioned on an end portion of rung 14 between and engaging opposed portions of the inside faces of

webs

21 and 22. Suitable forces are now applied, as spinning, swaging, crimping or the like, to form a terminal flange 29, FIGURE 4, on the end of rung 14, meanwhile applying pressure to clamp a portion of web 21 between bead 13 and spacer 28 and a portion of web 22 between flange 29 and said spacer. In the course of these operations, a portion of metal of the engaged rung end is caused to flow outwardly into notch 27 to form a detent or radial key 30 in said notch and thus to anchor rung 14 against rotation in

holes

25 and 26. When the desired number of rungs have been mounted in the rail 20 as above described, the end channel 23 is applied to close the longitudinal opening between the

webs

21 and 22 where it is secured by any suitable means, as welding, not shown. In the just described structure, the spacer and other, parts have functions corresponding to those noted in connection with the FIGURE 2 embodiment but with no flared out deformation of the rung and spacer.

The procedure illustrated in FIGURE 5 applies to the making of a ladder wherein the rails are of the box type, such as continuous or unitary tubes 10, as indicated in FIGURES 1 and 2 for example. However, the rail 14 FIGURE 5, has

holes

31, 32 of the same diameter, approximately that of the outside of the rung 14. To bring a spacer, as 28 into register with

holes

31 and 32, said spacer is engaged with a suitable pusher including a head 33 and a handle 34. Said head with a spacer in operative relation thereto is extended into rail 10 through its open (lower) end as seen in FIGURE 5 until the spacer reaches the desired position in register with

holes

31, 32. While the spacer is so positioned, rung 14 is moved in the direction (left) of the arrow, FIGURE 5, to its dotted line position as there indicated. Subsequent operations as spinning, crimping, swaging, or the like, are carried out as described in connection with the FIGURE 4 embodiment and with equivalent results.

In a modification, FIGURE 6, involving an open type or channel rail 40, the web 41 thereof is provided with a hole 42 having a diameter substantially that of rung 14. In this case, the end portion of rung 14 is extended through hole 42 to an extent to bring head 13 snugly' against the outer face of said Web 41 and to bring the end of said rung beyond the inner face of said web 41. While the parts are held securely in this relation, forces are applied in a known manner to said extended end to form a terminal flange 43 and to press a portion 44 of the metal of rung 14 into notch 27. Or, where the rung is not initially beaded, both said head 13 and said flange 43 may be formed with the rung in operative position and substantially simultaneously while the rung end engages hole 27 by applying suitable known crimping, pressing or other appropriate devices to said end portion of the rung. This produces a connection between web 41 and rung 14 wherein the edge portions of said web around hole 42 are securely clamped between flange or head 13 and flange 43.

From the foregoing it is apparent that the structures and procedures described above are well suited to attain the ends and objects herein suggested or directly set forth; that said structures can be manufactured and said method be practiced readily by conventional fabrication techniques; and that the various features and arrangements of parts and steps of method can be modified so as best to suit a particular purpose or use. Certain features of the disclosure may be used to advantage in particular applications without a concurrent use therewith of other specific features; and the elimination or modification of such specific features from an embodiment or procedure is to be construed as bringing such apparatus or method within the scope of this invention, unless specifically excluded by the terms of the following claims or required by the state of the prior art.

I claim:

1. Method of connecting a tubular ladder rung of malleable metal to a box-type ladder side rail having spaced side webs, which method includes the steps of providing said side webs with opposed coaxial circular holes each adapted to receive an end portion of the rung, providing the rung with a peripheral outwardly extending bead spaced from the end thereof, assembling said rail and said rung with said end of the rung engaged in and extending through said holes, with said bead engaging one of said webs, with a spacer collar interposed between opposed inner wall surfaces of said webs and embracing said rung end portion positioned between said opposed holes, and with a terminal portion of said rung end extending beyond the other of said webs, and deforming said terminal portion of the rung to form a flange engaging said other web.

2. Method according to claim 1 wherein said other web is provided with a generally regularly shaped rung receiving hole having its edge interrupted by a notch, and said step of deforming said terminal portion of the rung to form a flange engaging said other web includes flowing metal of the rung radially outwardly into said 1 notch while confining said portion against lateral flow inwardly from said flange.

3. Method according to claim 1 and wherein the hole in the second mentioned web is of greater diameter than that in the first mentioned web and said spacer collar is moved into position embracing said end of the rung through said opening of greater diameter.

4. Method according to'claim 3 and wherein portions of said rung end and said spacer collar are expanded outwardly to bring an edge of said collar opposite portions of said second mentioned web adjacent to said larger hole thereby clamping said last mentioned portions between said collar edge and said flange.

5. Method of connecting a tubular rung of malleable metal having a peripheral outwardly extending bead spaced from the end thereof to a box-type ladder side rail having spaced side webs, which includes the steps of providing one side web of said rail with a circular hole of aprpoximately the same diameter as the rung, providing the other side web with a circular hole opposite to and coaxial with said first hole, assembling said end portion of the rung with said holes and with a cylindrical spacer collar mounted on said rung between opposed inner wall surfaces of said Webs and embracing a portion of said rung end with a terminal portion of said rung end extending beyond said second mentioned hole and with said bead engaging said one side web about the hole therein, and deforming said terminal portion of the rung to form rail clamping abutments engaging outer face portions of said side webs.

6. Method of connecting a tubular rung of malleable metal having a peripheral outwardly extending bead spaced from the end thereof to a box-type ladder side rail having spaced side webs, which includes the steps of providing one side Web of said rail with a circular hole of approximately the same diameter as the rung, providing the other side web with a circular hole opposite to and coaxial with said first hole, moving a tubular spacer into position in said rail between and coaxial with said opposed holes, assembling said end of the rung coaxially with said holes and said spacer with said bead engaging said one side web about the hole therein, and deforming said end of the rung to form rail clamping abutments engaging outer face portions of said webs.

7. Method according to claim 6 and wherein the rail is a tubular wall open at one end and of generally rectangular cross-sectional contour and the tubular spacer is moved through said open end and longitudinally along said wall into rung receiving position between said opposed openings in the rail webs.

8. Method according to claim 6 and wherein the rail is a composite tube of approximately rectangular crosssectional contour with said webs forming the side walls thereof and with one end wall initially separate from said webs leaving a longitudinal opening extending the length of the rail, and the tubular spacer is moved through said opening into position coaxial with said opposed ho es.

9. Method of connecting a tubular ladder rung of malleable metal having a peripheral outwardly extending bead spaced from the end thereof to a box-type ladder said rail having spaced substantially parallel side outer and inner webs, which method includes the steps of providing said side webs with opposed coaxial holes adapted, respectively, to receive an outer end portion of the rung and a portion spaced inwardly therefrom, assembling said rail and each said rung with a rung end engaged in and extending through said opposed holes with said bead engaging said inner web about the hole therein and with a spacer collar mounted on said rung end between opposed substantially parallel inner wall surfaces of said webs at the peripheries of said opposed holes, and with a terminal portion of said rung end extending beyond the outer one of said webs, and deforming end portions of the rung to provide peripheral flanges engaging outer face portions of said webs while maintaining said face portions in substantially undeformed condition at the ends of said spacers.

10. Method according to claim 9 and wherein the rail and with said holes in the webs coaxially related, moving the spacer through the open opposite side of the assembled webs into position coaxial with and between said holes, engaging the rung end in said holes and said spacer and assembling said other channel to close said open side.

12. The method of making ladders from parts comprising rungs, spacers and tubular side rails, each rung having a peripheral outwardly extending bead spaced from the end thereof, and each rail having an open end and opposed rung receiving holes of approximately the same diameter as the rungs, which method includes the steps of moving a spacer longitudinally through said open end of a rail into a position in said rail coaxial with said opposed holes, inserting an end of a rung through said holes and said spacer with said bead engaging the inner web of each of said rails about the hole therein, and upsetting portions of the rung to provide peripheral flanges thereon securely engaging opposite sides of said rail.

13. The method of making ladders from rungs, each rung having a peripheral outwardly extending bead spaced from the end thereof, rail parts including end channels and side webs provided with holes to receive rung ends, and tubular rung embracing web spacers, which method includes the steps of assembling a channel and opposed webs in spaced relation with a hole in one web coaxial with a hole in the opposite web, said channel being arranged to engage said webs to close one side opening between opposite longitudinal edges thereof, inserting a tubular spacer into the space between said webs through the other side opening and in a position coaxial with said holes, moving a rung end through the opposed holes in the webs with said head engaging the inner web of each of said rails about the hole therein, applying a channel to close said other side opening and thus to complete circumferential closure of the tubular rail, and upsetting portions of the rung to provide peripheral flanges thereon in clamping position at opposite sides of said rail.

14. Method according to claim 9 and wherein each hole in the outer web is of greater diameter than the opposite hole in the inner web and each spacer collar is brought into operation position embracing said rung end by being moved thereto co-axially with the rung through said larger diameter hole in the outer web.

References (Iited UNITED STATES PATENTS 1,684,932 9/ 1928 Weatherhead. 3,004,625 10/1961 Arnold 182-228 3,039,186 6/1962 Stoyer et al. 29523 X 3,119,435 1/1964 Greenman 29512 X FOREIGN PATENTS 587,952 5/ 1947 Great Britain. 667,843 3/ 1952 Great Britain.

CHARLIE T. MOON, Primary Examiner.

UNITED STATES PATENT OFFICE CERTIFICATE OF CORRECTION Patent No. 3,327,385 June 27, 1967 Raymond H. Shaver It is hereby certified that error appears in the above numbered patent requiring correction and that the said Letters Patent should read as corrected below.

Column 4, line 62, after "flowing" insert a portion of the Signed and sealed this 11th day of June 1968.

(SEAL) Attest:

EDWARD J. BRENNER Edward M. Fletcher, 11'.

Commissioner of Patents Attesting Officer

Claims

1. METHOD OF CONNECTING A TUBULAR LADDER RUNG OF MALLEABLE METAL TO A BOX-TYPE LADDER SIDES RAIL HAVING SPACED SIDE WEBS, WHICH METHOD INCLUDES THE STEPS OF PROVIDING SAID SIDE WEBS WITH OPPOSED COAXIAL CIRCULAR HOLES EACH ADAPTED TO RECEIVE AN END PORTION OF THE RUNG, PROVIDING THE RUNG WITH A PERIPHERAL OUTWARDLY EXTENDING BEAD SPACED FROM THE END THEREOF, ASSEMBLING SAID RAIL AND SAID RUNG WITH SAID END OF THE RUNG ENGAGED IN AN EXTENDING THROUGH SAID HOLES, WITH SAID BEAD ENGAGING ONE OF SAID WEBS, WITH A SPACER COLLAR INTERPOSED BETWEEN OPPOSED INNER WALL SURFACES OF SAID WEBS AND EMBRACING SAID RUNG END PORTION POSITIONED BETWEEN SAID OPPOSED HOLES, AND WITH A TERMINAL PORTION OF SAID RUNG END EXTENDING BEYOND THE OTHER OF SAID WEBS, AND DEFORMING SAID TERMINAL PORTION OF THE RUG TO FORM A FLANGE ENGAGING SAID OTHER WEB.