US2378913A - Flexible ladder - Google Patents

Description

June 2:6 1945- N.`| DAHLANDER 2,378,913

FLEXIBLE LADDER Filed Jan'.l 8, 1943 2 Sheets-Sheet l lllllljllll n INVENTOR y /Voa @AHM/vof@ 4 ATTORNEY June 26, 1945. N. l.. DAHLANDER 378,913

FLEXIBLE LADDER Filed Jan. 8, 1943 2 Sheets-Sheet -2 L N' i 'fr Ng INVENTOR ATTCRNEY is aimed to Patented June 26, 1945 2,378,913 i FLEXIBLE LADDER Neel L. paidaiider, New York, N. assigner di oneehalf to Robert J Earl, New Canaan, Conn.

Application `January 8, 1943, Serial No. 471,663 8 claims. (ci. t28- 40) This invention relatestoimprovements in flexisle iedders, 'such as chain ladders and the like. Among the objects of the present invention it provide an'improved flexible ladder `aving rig-id rungs, spacing means mounted on the rungs adjacent to tne'suspensor'y elements,`

which spacing elements will be provided with an annular peripheral il'ange of suflcient `Width to yforni` an. extensive Wearing `surface as distinguishedyfrcm the `cutting ledge of` a disc or the like, and which spacing means will beanchored against rotation to reduce @the Wear 'to `a mini-` mum I l L tIt is still another object of the `present `invention to provide an improved eikible ladder such as a Vchain ladder having rigid rungs and 'spacing disks 4mounted on the rungs aiidcooperating with the suspensory members to insure the proper alinement of the individual elements ofthe suspensory members, maintain the suspensory members and spacing members adjacent to one an other and yet reduce to a minimum thepints of engagement between the suspensory members and` the spacing members.

'Ihese and other featurescapabilities and advantages of the invention will appear from the Isubjoined detailjdescription "of specic embodiments thereofillustrated in the accompanying drawings in which 1 `Figure 1U is alfront fragmental elevation bf part of a nexible chain `made according to` one embodiment of thepresent invention.

Fig. 2 is a fragmental enlarged detail partly in section showing the association of rung spacing member and suspensory member made aocordimg id me embodiment iuustrated in Fiel 1.

lljigr d is a. `section on the line 3--3 of Fig; 2.

gi 4 isla perspective of the spacingmember shown inFig. Figi 5 is a fragmental front elevation of an'-` otner embodiment of the present invention.

d Fig. 6 is an enlarged fragmental detail partly in section showing the association of rung space ingu member and -suspensory `member according to the embodiment illustrated in Fig. 5.

d j 'lis a section on the line 'Il "of Fig. 6.

E d is" a side elevation `of the spacing element show-n inFig. 6.

According to the embodiment illustrated in Rigs. 1 to 4, inclusive, the flexible ladder there shnwn is provided with rigid rungs I preferably composed of `cylindrical metal baraea'chl having a pair of alined slots `2 .and 3 at their ends diaintrillydisposed. The rsuspeis'nry members I and 5 are preferably composed of a plurality of chain links s, as an instance oi trie type known as the Lock Link type theloop 1 of` `which is engaged bythe looped ends B and 9 of an adja# cent link as shown in Fig. 2. The loop 1 asshown has two Shanks Illiand II. Advantage is taken of thisoonstruetien in the present instance to locate the two Shanks Ill` and II` ofthe loop 'I in the slots 2 and 3 of the bar I with the lower loop eiitendingbeyond the slot 3 to receive the looped ends 8 and 9 of the adjacentlower link Bfand the upprlcoped endsr and 9 ofthe loop I of the link 8 disposed above the slot 2 to engage the loop 1 of the next above adjacent link 6. 3

The slots 2 and@ are preferably `long enough asshown to receive theshanks I0 and II, with the shank IU adjacent the innerendsof the slots 2 and 3,and the shank II free to be engaged by the inner face of the inwardly extending annular :tone II5 and the inner faces of the projections I2 and `I3 extending `radially inward from the periphery ofthe central opening I4 in the annu# lar 'zone H5 of the spacing member I5. The projections I2 and I3 are preferably as shown diametrically opposite to one another relative to the opening I4 and of alwidthvto i'lt nicely in the slots 2 and 3 as shown in Fig. 2. The spacing member I5issecurediln position either ley turn ing over thefree outer edge I Bcf the bar I, as an instance by burring, `or by welding, brazing ,or otherwise securing the outer edge I6 of the bar I to the spacing member I5, v1

`In order to savematerial and to reduce the weight of the member I5 without materially ree du'cing itsstrength, the openings II are formed in the disc portion I8 of the member I5. The spacing member I5 is also provided with a ange I9 the Width of which is predetermined to enable its inner free edge 'to aline the inner face of the annular `zone `I I5 and the inner faces of the projections I2 and I3 asshown to engage the Shanks II of links 6 disposed aboveandbelow the link 6 extending through the bar I via the slots 2 and 3. The disc portion I8 of the spacing member I5 is circular and the iiange I8 and zone IIS .annular and 'circular in theinterest of reinforcing the spacingnmember I 5, `and `the `flange I9-, `Wide enough and provided withl an outer smooth snr-` face to form a smooth wide engagement sur-face for engaging the side of the vessel with which the latter is to be used,` thereby to minimize the danger of fracturing the side ofthe vessel which might occur with a sharp edged disc, especially with the thin `hulls today extensively used Ain the war 'work for'lighter craft, the greater the width of the flange iSd-of course, the greater `latitude for distributing the load or force exercised against the side of the vessel by the spacing member I5.

While the dimensions of the spacing member I may vary according to the service to be performed, it should be noted that excellent results have been achieved when the over-all diameter of they disc portion I8 is ve inches and the width of the ange I9 is about one-fourth of an inch, when the diameter of the bar of the rung is about one and one-fourth inches. While the zone H5, the projections I2 and I3 and the flange I9 practically engage the shanks of the links 6 in actual use, this engagement should not be a locking engagement, but allow free movement of the outer links 6, as an instance to fold over Aupon one another when it is desired to store the ladder,

and also to allow for curves or bends in the face of the vessel. l

The anchoring of the spacing members |5 onto the bars I by the cooperation of the projections f I2 and I3 with the slots-.2 and 3 prevents needlessturning and consequent loosening due to the wear vof the spacing members I5 relative to the bars The'alinement of the links 6 and the suspensory members 4 and 5 afforded by the flange I9 tends more evenly to distribute the stresses and strains to which the ladder is subjected and to avoid the stresses and strains that would arise due to accidental misalinement' of the links with one another, particularly adjacent the points ,Where the forces are applied,as an instance, on the rungsA during use.

Preferably as shown, the looped ends 8 and 3 of the adjacent lowerlink `6 are disposed at the upper'end of such link to receive the bar I and thereby aid in locking the link in place, it having been found in practice that there is a tendency to open the link when the looped ends 8 and 9 of the link B extending through the bar I are at the bottom instead of at the top.

In actual practice it has also been found that excellent results have been obtained when the several parts, to'wit, bar I, links 6, and spacing member l5, are composed of steel. y

In the embodiment shown in Figs. 5 to 8, inclusive, there is shown va flexible ladder having a rigidrung 20, preferably composed of a Wooden bar, circular in cross section as shown, provided with diminished ends 2|, the cross sections of which as shown in Fig. 7 are oblong, the narrow axis of which is preferably less than the width between 'the two shanks 22 and 23 of a. link 24 of the"Lock Link type, the long axis of which is preferably greater than the width between the two Shanks 22 and 23 as shown in order to facilitate in anchoring the bar 23 against rotation and to the suspensory member 25 composed of links of this type as shown. On each diminished oblong end 2| there is rst mounted a spacing member 26 having a disc portion 21 provided with openings 28 in the interest of saving material and to' reduce the weight thereof without materially reducing the strength of the spacing member 26. The spacing member 26 lalso has a central oblong opening 29 provided with two arcuate flanges 33 and 3| along the opposite long sides of the oblong opening 29, the inner faces of the anges30 and 3| conforming to the louter long curved faces' of the diminished end 2| so that the spacing member may be mounted on the' diminished portion 2| with its flanges 30 and 3| extending outwardly as shown in Fig. 6 toward the suspensory member 25. After the spacing member 26 has been mounted upon the diminished portion 2|, then the suspensory member 25 is secured to the diminished portion 2l by having the diminished portion 2| pass between the'shanks 22 and 23 of a link 24 as shown in Fig. 6. Thereupon an 0blong metal ring 32 is forced on the peripheral end of the diminished portion 2|, and then a metal disc 33 secured to the free plane end of the diminished portion 2| by the screw 34, the disc 33 extending beyond the ring 32 to anchor the same in position. l

- Each spacing member 26 is provided with an outer peripheral flange 35, the width of which is the same as the width of the flanges 30 and 3|, in order to permit alinement of adjacent links 24 of the suspensory member 25. In other words, the flanges 30 and 3| will engage the sides of the shanks 22 and 23 of the link 213 spanning the diminished portion 2| while the flange 35 will engage the shank portions 22 and 23 not only of the link 24 below the link spanning the portion 2|, but also engage the shank portions 22" and 23 ofthe link 23 above the link 2d spanning the portion 2|. 7 y

Preferably as shown with' the embodiment first described, the looped ends 35 and'31 of each link 24 will be disposed at the upper end thereof so that'the rung 20 may rest upon the looped ends 33 and 31 of the link 24 below the link "ll spanning the diminished portion 2 `The looped ends 33 and 31 in the present embodiment not only rest'against the ring 32 as shown inFig. 6, but also are disposed opposite the lower space between the flanges 30 and 3i so that the looped ends 35 and 31 will not be engaged by the sharp edge of the spacing member 23.

With this embodiment also, thev dimensions will depend upon the service to be performed. ll-Iowever, excellent results have been achieved in practice when the diameter of the circular portion of the rung 20 is about onerand one-fourth inches over-all, the screw 3d is aboutr two inches in length, the diminished portion 2| aboutthreefourths of an inch in width, the diameter of the spacing member about five inches, and the width of the ange 35 as well as of the flanges 3&3` and suspensory members 25. While-in use, the Wear-s ing ring 32 will rest on the looped ends 33 and 31, when it is desired to store the ladder, the suspensory members 25 will be free to Viiex outwardly away from the rungs 20 to facilitate folding up theladder and conining ity to a compact space.. When the'suspensory members 25 are'js'o folded outwardly, obviously the'links will permit pivotal motion practically in all directions v'and allowthe rungs with their spacing members 25 to be freely staggered relative toone another,`

With both embodiments, furthermore, it willbe noted that the spacing members will reduce toa minimum the engaging surfaces between the-same and the suspensory members, 'thereby 'reducing to a minimum the wear on the suspensory-'members without in any way impairing the utility of the same, and on the other hand actually make possible the use of an extended bearing surface,

ofthe vessel. q

cationsmay bemade to the details of construction Without departing from the general spirit of the invention as set forth in thevappended claims.

I claim:

1. In a ladder, the `combination of two flexible 'e suspensory members composed ofchain links, rigid rungs having slots at the ends thereof to receive links of said members and resting on the ends of links, and spacing members mounted on said rungs adjacent the outer sides of said suspensory members, each spacing member having a free edge `of its flange, the free edge of said surface for the spacing `member `between the central opening to receive the end of a rung, an Y outer uninterrupted circularange the free edge i of which and a portion adjacent its central open` ing being in radial alinement with one` another l and in engagement with `three successive links of `one of said suspensory members to aline the same, said` iiange` forming an extended bearing surface for the spacing member between the spac-` ing member and the face ofthe vessel `to be en` gaged, said rungs having fastening means on the outer free ends thereof to anchor said suspensory ing within centrally formed depressions in said spacing members. i

2. In a ladder the combination of two iiexible suspensory members composed of chain links, rigid rungs having slots attheir ends to receive links of said suspensory members and resting on the ends of links, and spacing members having de; pressions deflecting inwardly with central "open` `members and spacing members in place and restflange and said centrally deilected portion being 'in engagement With successive linksof one of said suspensory members to serve to aline `the same, said llangeforming an extended bearing spacingmember and the face of the vessel to be enga-ged, said rungs having fasteningmeans on the outer free ends thereof to anchor said sus#` pensory members and spacing members in place and resting within the centrally formed depressions in said spacing members. i

3. In a ladder the combination of `two flexible `suspensory members composed "of chain links, holloW metal rungs having slots at their ends to re-` ceive links of said suspensory members and an- A chor the same against rotation relative to said 1 rungs, spacing `members having central openmgs 4 to receive the ends-of said rungsand having projections extending` into said slots to anchor the` spacing members against rotation relative to said rungs, the ends of said rungs being burred` and i disposed.` against the outer faces of said spacing n members, each `spacing member having a centrally v depressed portion engaging the adjacent link and also having an outer annular flange parallel to the axis of its associated rung and extending in-` wardly with the free edge of the flange engaging links to either end of the link confined in the associated rung, With'the burrs at the ends of ingsto receive the ends of said rungs, each spac- ,ing member having an outer annular flange and a portion adjacent its central opening formed by the rungs resting within the centrally formed depressions in` said spacing members. i

t NOEL L. DAHLANDER.

i said depression and in radiaiaunement with the

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