US2667296A - Aerial ladder - Google Patents

Description

Jan. 26, 1954 H. J. TRocHE ET A1. 2,667,296

AERIAL LADDER Filed Feb. 18, 1950 5 Sheets-Sheet l HERMA/v J' Tfw CHE BYru-s Ha wana Ho/.AN

Jan- 26, 1954 H. J. TRocHE ET AL 2,667,296

AERIAL LADDER Filed Feb. 18, 1950 5 Sheets-Sheet 2 A; l p l' @i V NTORJ. l #fR/14N f, Roc/v5 f lm l JZMES Howlin@ HaLA/v BY )Lw fromm Jan. 26, 1954 H. J. TROCHE ET AL 2,667,296

AERIAL LADDER Filed Feb. 18, 195o 5 sheets-sheet s A7701? EY Jarf- 26, 1954 H. J. TRocHE ET AL 2,667,296

l AERIAL LADDER Filed Feb. 18, 1950 5 Sheets-Sheet 4 INVENTORJ. HERMA/v J TocHE Z4/751s Hawano flo/.AN

Jan. 26, 1954 H. J. TRocHE Erm. 2,667,296

AERIAL LADDER Filed Feb. 1s, 195o 5 sheets-sheet 5 INI/ENTOR. Har/MN J.' TnocHE 3 Jil/wes Ho wana Hua/v Patented Jan. 26, 1954 Howard Holan, Rocky River, Ohio, assignors to J. H. Holan Corporation, Cleveland, Ohio, a.

corporation of' Ohio Application February 18, 1950, Serial No. 145,056

2 Claims.

The invention relates to aerial ladders, and particularly to aerial extension ladders adapted to be. mounted onutility truck bodies and utilized in the installation and maintenance of utility line equipment. The improved aerial ladder when not in use or when being transported is also bedded on the truck body in closed condition.

The objects of the invention are to provide an aerial ladder of the character stated which is of lightweight and may readily and easily be removed from its bed, shifted into different positions and extended, collapsed and restored to its bed, all by one operator; which is storable in or on the truck body for transporting without the loss of storage and crew space; which has a wide range of operating positions; and which provides a high factor of safety for the workmen.

The annexed drawings and the following description set forth in detail certain means illustrating the improvements in aerial ladders, such means constituting, however, only one of Vthe various forms in which the principle of the invention may be embodied.

In said annexed drawings:

Figure 1 is a side elevation of the aerial ladder, with the parts thereof extended to substantially its full working position, the position of the ladder being that in which it has been tilted down from its bed, extended, and is in a position where it can be turned about into diiferent angular positions relative to the truck body upon which it is mounted, the position shown in Figure 1 being that in which the extended ladder can be utilized longitudinally of the truck body; a part of the truck body being also shown in the ligure; also, there is shown in dot-and-dash lines a nested transporting position of the ladder upon the roof of the truck body, the two parts of the ladder being in closed condition; v

Figure 2 is a side elevation of an extreme outboard working position of the ladder, a position in which the ladder has been turned substantially 90 from the position thereof shown in Figure l and moved outboard at the top, certain other outboard positions through which the ladder moves in reaching the full line position shown in Figure 2 being indicated by dot-and-dash lines, the lefthand dot-and-dash position shown being a turning ladder position, diifering by 90 from the turning position shown in Figure l, this left-hand dot-and-dash position shown in Figure 2 being one in which the ladder can be utilized in a substantially vertical position but pointed outboard of the truck body, or being one which is preparatory to the further desired exact positioning of the ladder outboard of the truck body, the extreme outboard positioning being indicated, as stated, by the full line showing of Figure 2;

Figure 3 is a diagrammatic View illustrating a rope and pulley structure for raising and lowering the upper ladder part;

Figure 4 is a side elevation, upon an enlarged scale, of a locking-assembly for securing the ladder upon the floor of the truck body, a non-locking position of an operating lever and some Yrelated elements being shown in dot-and-dash lines, this mechanism being utilized for locking the ladder for operation thereof substantially vertically, either longitudinally or pointed outboard of the truck body, although when the ladder is used longitudinally of the truck body or pointed outboard and used substantially vertically of the truck body, it is not necessary to use this locking assembly, as will be hereinafter yfully described, this locking assembly in these uses being utilized, if desired, as an added safety feature;

Figure 5 is a front elevation of the elements shown in Figure 4, taken in the plane indicated by the line 5 5, Figure 4;

Figure 6A is a vertical transverse section, upon an enlarged scale, taken in a plane substantially at right angles lto the plane of the ladder, this gure plane being indicated by the line 6 6, Fgure 5;

Figure 7 is a fragmentary plan'section of a ladder stile and rung anda clamping mechanism detail, upon an enlarged scale, taken at right angles to the plane of the ladder and in thev plane l indicated by the line 1 1, Figure 5;

Figure 8 is a broken plan view, upon an enlarged scale, of a pivot plate secured to the floor of the truck bodyand of a base pivotally-mounted adjacent one of its ends on a side wall of the truck body and adapted to be swung from an idle position adjacent the wa-ll of the truck body down to a working position where it rests upon the oor of the truck body, as shown in Figure 9, the iree or swinging end of the base in-its lower position extending substantially to the longitudinal center line of the truck body, the base being shown in this Figure 8 in a lower ladder supporting position on the floor of the truckY body, and the view being taken `from the plane indicated by the line 8 8, Figure 2, this view also indicating in broken lines a bottom end ladder channel extended between the side rails or Stiles of a lower ladder section, and also channel brackets exteriorly of the rails of the lower ladder section, through which channel brackets the ladder-lockine' bolts extend;

Figure 9 is a fragmentary vertical section, taken transversely of the truck body and from the plane indicated by the line 9 9, Figure 8, and on the lower part of Fig. 8;

Figure 10 is a fragmentary vertical section, taken longitudinally of the truck body and in the plane indicated by the line Iii-Ill, Figure 9;

Figure 11 is an elevation, upon an enlarged scale, taken substantially at right angles to the plane of the ladder, of one of a pair of certain automatic vclamps mounted on the stiles of the lower ladder part for locking the ladder to certain relatively right-angular pivot tubes mounted upon the truck body, respectively adjacent one side of the truck body, and transversely of the truck body, and adjacent the top of the latter, this view being an illustrative one in which the will be hereinafter fully described. `When the clamp is shown as being locked to the pivot tube extended longitudinally "of the truck body and thus the Vladder is in position for use outboard of the truck body; and f Figure 12 is a broken section, partially in plan,

taken in a plane at right angles to the plane of the ladder and indicated by the line I2-I2, Figure 11.

It will rst be stated that aerial ladders of the character herein presented are so designed and mounted that they may be utilized for servicing operations directly above the truck body or outboard thereof to the road curb and beyond. When working directly overhead, the truck body can be operated so that one overhead position ofthe ladder serves the purpose. However, when working outboard, there must be considerable latitude to the reach of the ladder in order to provide for all reasonable uses thereof and, furthermore, the curb side of the street is often blocked by parked vehicles and other obstructions so that the ladder must be utilized over such obstructions from a position in the street inwardly of the curb. Y

Referring to the annexed drawings in which the same parts are indicated by the saine respective numbers in the several views, a sloped skeleton frame 2 movable transversely of the truck body, Figure 2, is pivotally mounted adjacent one edge on and adjacent the bottom of the inside face of a side wall of a truck body I, within the truck body, Figures 2, 8 and 9. The opposed longitudinally-spaced sides of the frame 2 are shown in Figure 8, and from Figure 9 it will be noted-that the lower ends 59 of these sides are wrapped about and secured to a shaft 3S pivotally mounted in brackets 48 secured to and adjacent Ythe bottom of the right-hand truck body side wall. Upon this skeleton frame 2 and its associated elements, when the frame is pulled down to ladder-receiving position upon the floor I1 of the truck body I in the manner hereinafter fully described, and as shown in Figures 8, 9, and 10, is mounted the improved aerial extension ladder for outboard use. The ladder has a stationary lower section 3 with rungs I9 and an upper slidable or extensible section d.,Y having wood rungs 2l and the rails I5 of which are slidable upon the rungs I9 of the lower section 3 for extending and closing the ladder. As stated, the skeleton frame 2 is utilized for supporting the ladder in its various outboard operating positions, the ladder in such positions bearing against and being clamped to a longitudinal pivot tube mounted, as hereinafter fully described, upon the roof of the truck body, the clamping of the ladder to the pivot tube 6 being such as to permit swinging of the ladder over said pivot tube. 'is

Yladder is utilized longitudinally of the truck body I, itis clamped to a cross-Wise pivot tube 5 for swinging movementthereover, this pivot tube 5 being mounted upon and above the roof of the truck body I.

The mounting for the cross-wise pivot tube 5 and the longitudinal pivot tube E comprises braced brackets 66 erected on the roof of the truck body I adjacent its sides to which the pivot tubes 5 and 6 are secured by plates tid welded to the pivot tubes 5 and 6 and to the braced brackets 66.

When the ladder is manipulated or utilized substantially vertically, either pointed longitudinally of the truck body I or pointed outboard of the truck body I, it is mounted upon a pivot plate 2d, Figure 8, and secured to the floor I1 of the truck body I by a pivot pin 25 passed through a central socket 26 of the pivot plate 2d, and registering sockets in the bottom ladder channel 9 and in the truck body floor I1, or is secured by locking bolts passed through transversely aligned sockets 35 or longitudinally aligned sockets 29 of the pivot plate 2d and registering sockets in the truck body floor I1, all as hereinafter fully described.

The axes of the cross-wise pivot tube 5 and the longitudinal pivot tube 6 lie in the same horizontal plane. These pivot tubes are provided with respective disks 33 between which the ladder is swivelly clamped to the pivot tubes.

The improved ladder may be mounted upon and used with either a truck body having a roof, or one without a roof, but is described'herein and shown in the accompanying drawings as utilized with a body having a sliding roof.

In transporting position the upper ladder part 4 rests upon the lower ladder part 3 and the shortened ladder assembly is carried above` the roof of the body I upon the cross-wise tube 5, Figure l, which tube 5 forms a support for one end of the closed ladder assembly, an opposite end ladder support 58 being provided which is erected upon the truck body I and has a ladder hold down part.

When it is desired to utilize the ladder, the hold down support 68 is unfastened and the closed ladder sections rocked over the tube 5 by pulling on the rear end of the lower ladder part 3 until the ladder assembly is in about a vertical position which aligns a central socket 91 of the bottom ladder channel 9, secured between the side rails I4 of the lower ladder section 3, and which in this position of the ladder extends crosswise of the truck body I, Figure l, with a central socket 25, Figures 1 and 8, formed through the pivot plate 24, there also being a socket 63 through the truck body floor I1 registering with the pivot plate socket 26. A removable taperedend pivot pin 25, Figure l, is dropped through the registering sockets and thus the closed ladder assembly is pivotally mounted upon the floor I1 of the truck body I and bears against the cross-wise pivot tube 5 to which it is Ypivotally locked as hereinafter fully described. The procedure Ljust described is a preparatory one if it is desired to use-theA ladder-outboard of the truck body l.

However, if it is desired to the ladder with its plane cross-wise of the truck body l, the pivot pin 255 may be inserted through the mentioned registering sockets, as described, or the ladder can be secured by engaging manually-movable depending locking bolts t2, Figures- 4 and 5, mounted exteriorly of theside rails i iat the lower end of the ladder vsection 3, with and looking them in opposed transversely-spaced sockets 35 formed through and 'adjacent the opposite Iongitudinally-extending sides of the pivot plate 2d, Figure 8, and registering with transversely-op'- posed sockets 63 formed in the bodyl floor il. If

it is desired to use the pivot pin and the pivot plate socket 2S and the sockets registering therewith, the locking bolts 'i2 andthe transverselyspaced sockets and the floor sockets registering therewith may be utilized as an added safety feature. The axes of the sockets 26 and 35i of the pivot plate 2d are in alignment transversely Assuming, however, that the desired position Y of the ladder is for its use in outboard operation, other than for use in a substantially vertical position but pointed outboard such as is shown by the left-hand dot-and-dash position of the ladder in Figure 2, it is turned angularly about upon 7 the pivot pin 25, from the position shown in Figure l to the left-hand dot-and-dash position shown in Figure 2. lf it is desired to use the ladder in the left-hand dot-and-dash position shown in Figure 2, the pivot pin 25 can be utilised to secure it. If additional security is desired, the locking bolts l2 can be engaged with longitudinally opposed sockets 2Q, Figure 8, of thepivot plate 2d, and registering longitudinally-spaced iloor sockets 53, which sockets 29 are in alignment with the central pivot plate socket 25 and are angularly 96 removed from the aforementioned transversely-aligned pivot plate sockets Se. However, if it is desired to use the ladder in a substantially inclined position, the pivot pin 25 f,

is removed, and the ladder moved bodily inwardly of the truck body i at the bottoni, and' the locking bolts l2 are engaged with a selected longitudinally-aligned pair of two series of transverse sockets 23 formed through inclined support plates 2l mounted on the inner or free ends of the respective arms of the skeleton frame 2, all as hereinafter fully described. There are a plurality of pairs of the longitudinaily-aligned sockets 23 and the adjacent pairs are transversely spaced and transversely-aligned. These pairs of sockets 2t are also transversely-aligned with the longitudinally-aligned sockets 2%' of the .pivot plate 2d.

As stated, the pivot pin 25 is a removable member and it is utilized in the socket 2B only for angular'rotating of the ladder and also for substantially vertical operation oi the ladder. When the ladder is to be utilized, it is locked yby the bolts 42 to the floor l1 through the sockets 29, or through the sockets t5, or locked in any longitudinally-aligned pair of the transverse series of sockets 2S formed in longitudinally-opposed inclined upper-flanged support strips v2l mounted on the longitudinally opposed arms of the atore' series of sockets 2.8? in the inclined. support strips lf'any one of the pairs of longitudinally'- aligned sockets 28 below the upper sockets 28, Figure I9, are utilized, the outboard position of the ladder would notibe as extreme as theposition-'tlf'iereoi` shown in Figure 2, that pair oi sockets 28 being utilized with Vthe locking bolts d'2 which will produce-'the desired .inclined or outboard position `of the ladder .within the range provided by the plurality of. pairs or sockets Z3.

w When not in use, the vpivot pin is temporarily stored in any convenient location such as on a pin v5!! mounted inthe side wall oi the truck body-i.

For the purpose of providing adequate depth of socket for the pivot pin 2.5 a substantial block t2 Figures 8 and 9, is welded to the bottom face of the truck body floor I1, this block 62 having a socket` registering with the pivot plate socket 26 and any other vertically-aligned sockets.

After the closed ladder has been rocked down to aposition. adjacent the ii'oor i1 of. the truck body, and pivotally secured in the socket 2t, or locked through the sockets 35 or swiveled for lateral positioning and/ or locking inthe sockets 29, or pulled outwardly at the bottom for locking in a pair of the inclined series of sockets 28, it is ek-` `tended to the amount desired by pulling the upper ladder part 4 upover the lower ladder part 3, this action consisting in. sliding the side rails i5 of the upper ladder part 4 over the rangsr i9 of` the Ylower ladder part '3. Substantially the makiinum amount of extensionis shown in Figures l and 2, this `extension being lto an extent in which the lower support bars 34 of the bridge of the strut bars 23 `of the upper ladder part 4 are about the heightof the upper rung l-fl l of the lower ladder part 3', providing an overlapping ladder part area indicated by 15, Figures land'z. This extension of the ladder Vis effected by pulling on a cordv "l, Figure 3, which tracks over a swivel pulley '8 mounted -on the bottom channel member 9 of lthe lower ladder section 3, thence tracks over a swivel pulley l0 depending from the top rung i i of the lowerlad'cler' section 3, thence tracks over a swivel pulley IZ mounted on the bottoni rung' i3 of the upper ladder section 4, and thence 'is vsecured to the upper'lrung .irl of the lower ladder rsec-- tion 3. 'I'he two ladder sections are of such tranwerse dimensions that this pulling upon the cord 'l causes the side rails i5 of the upper ladder section 4 to travel upwardly upon the rungs i9 of the lower ladder section 3. In the accompany-ing drawings the side rails i5 of the upper ladder section 4 are shown as traveling on end wear collars '28 of the lower section rungs i9, Figure 5.

Describing now in detail the structure and operation of the several elements and assemblies by which the vaforedescribed manipulation and use ofthe ladder 'are effected.

The structure and actuation -o the pivoted skeleton frame 2 are as follows. As stated, this frame 12 is fastened to the inside face of the Y right-'hand side Aof the body i, when not in use,

.removing a lock pinand chain assembly there- 8, 9, and l0, welded at their bottom edges to the two sides of the skeleton frame 2 and secured at their lower ends to collars 32 secured to the shaft 3Q, against which collars 32 the end mountings 48 of the shaft 3S abut. The supports 2l 'are each providedwiththe series of four transversely-spaced sockets 28 therethrough transversely-aligned with the sockets 29 of the pivot plate 24 and adapted to receive the hinged locking bolts 42 depending. from the links 4t of two locking mechanisms, Figures 4 and 5. These locking mechanisms depend from and exteriorly of the side rails Id of the ladder section 3, Figures 4 and 5. The plurality of pairs of longitudinally-aligned sockets 28, and the inclination of the inclined support plates 2l through which they are formed, provide means whereby the ladder can be positioned and locked laterally outboard at different inclinations therefor, the estreme position of which is shown by the full line ladder position ofFigure 2.

The means for actuating the locking bolts 42 are shown in Figures 4 to 7, inclusive. A hand lever 3b is pivotally secured at one end to a shell 38 which is mounted in the ladder rails I4 and forms the bottom rung of the lower ladder section 3 in combination with stub end shafts 37. Pivoted at one end to the lever 36 intermediate the ends of the latter is a link 40 pivoted at its opposite end which is offset, Figures 4 and 5, to one end of a locking bolt 42. The locking bolt 42 passes through the upper and lower anges of a channel bracket comprising an angle member 43 and an angle member 431 which are secured together and also bolted to and eXteriorly of a brace 49 for the ladder rail I4. Adjacent the bottom of the bolt 42, and encircling it, within the bracket I3-431, is a collar 45 which is adapted to impinge upon an adjacently lower block 451 secured to the inside face of the bracket member 431. Mounted between the inside face of the bracket member 43 and the top face of the collar 45 is a compression spring 44 secured at its bottom end to the collar 45.

There is one of the locking mechanisms just described mounted upon each side rail I4 of the lower ladder part 3 except that the locking mechanism on the right-hand rail I4 is not provided with a hand lever 36. In lieu of this hand lever 36, the right-hand locking mechanism is provided with a short link 39, Figure 5, pivotally secured to the shell 38 at one end and pivoted to the link 46 at its opposite end.

The locking mechanisms upon the two sides of the ladder are secured together by a channel bar 46, Figure 7, whose respective legs are secured to the two ends of the shell 38 adjacently exteriorly of the ladder rails I4.

The locking bolts 42, when in ladder-locking position, pass through the sockets 35, Figure 8, of the pivot plate 24 and also through aligned holes in the iioor I1 of the truck body I, when V the ladder is used'longitudinally of the truck body I, and pass through selective pairs of sockets 28 in the support strips 2l, when the ladder is used outboard of the truck body I, and also pass through the sockets 29 of the pivot plate 24 and aligned holes in the floor I1 of the truck body I, when the ladder is used in a substantially vertical position, but is pointed outboard of the truck Vbody I, as shown by the left-hand dotand-dash position thereof in Figure 2.

It is evident from an inspection of .Figure 4 y that pulling downwardly upon the hand lever 36 will cause the upper end of link bar 4B to swing outwardly and downwardly from the dotand-dash non-locking position thereof shown and permit the springs 44 to effect the downward movement of the locking bolt 42 whereby the locking bolt 42 will be caused to pass through the sockets 29 or 35 of the pivot plate 24, and the registering sockets in the iloor- I1 ofthe truck body I, or through a pair of the longitudinally-aligned holes 2B of the support strips 2l, all depending upon the position of the ladder and the directionin which it is pointing and, in the event the ladder is resting upon the pivot bar 6 and is outboard, depending upon the inclination of the ladder.

When it is desired to release the locking bolts 42, the hand lever 35 is pushed toward the dotand-dash position thereof shown in Figure 4, whereby the bolts 42 are lifted into ladder-unlocking positions and the links 41% pass the projections of the axes of the bolts 42.

U-straps 41 secured to the links 40 intersect the locking paths of movement of the hand lever 35 and the short link 35 whereby the extent of the locking movement of the bolts 42 is' limited.

As above stated, the ladder is normally swingingly clamped to the cross tube 5 and this tube 5 serves to hold and support the bottom end of the ladder in transporting position and provides an overbalancing medium over which to rock the ladder down preparatory to use thereof as well as providing a clamping medium for the ladder for use thereof longitudinally of the truck body I. For use of the ladder pointed outboard of the truck body I, or used outboard of the truck body I, the longitudinal pivot tube is the one to which the ladder is pivotally clamped for swinging movement of the ladder. The normal position of the clamping means is the locked position which is assumed automatically upon contact of the clamping means with the pivot bar 5 or the pivot bar 8. These clamping means, and the elements for unclamping them, are shown in detail in Figures ll and l2. Assuming that it is desired to use the ladder outboard, or pointed outboard, pivot tube Si would be the one utilized and, for illustrative purposes, this is the condition shown in Figures ll and 12. Adjacently inwardly of the longitudinal pivot tube and parallel therewith is mounted in the side rails I4 of the lower ladder section 3 a shell Se through which extends a shaft 5I to whose projecting ends hubs 5l are pinned. A release lever 55 is pinned to the left-hand hub 5l. The hubs ii? are disposed slightly inwardly of the lateral ladderaligning disks 33 which overlap the hubs 5l. Formed integrally with the inner ends of the hubs 5l are coupling elements pivotally mounted on the shaft -5I and having each a jaw 53 and a tail piece 54. Abutting the outer side face of the rail I4 is a support bar I3 for the strut rod 22 of the lower ladder section 3, through which bar I8 the shaft 5I and shell 56 pass, as also a coll spring 58 one end of which is secured in the rail I4 and the other end of which is secured in an enlarged end portion 541 of the hub 51 with which the coupling element is integrally forned. The inner edges of the support portions I8 overlap the rails I4 of the lower ladder section 3. The tendency of the spring 58 is to turn the hub 51 and the release lever 55 and consequently the coupling member so as to cause the jaw 53 of the latter to clamp down over the pivot bar 6 as shown in Figure 1l. 'I'he outer end of the strut support member I8 has an arcuate portion |81 adapted to engage the pivot tube 5 and thence is of sub-divided nature so as to provide upper and lower pads which have inwardly converging guide surfaces 6D and 681 which, as the clamping member, upon the movement of the ladder, approaches the pivot bar 5 pass over the upper and lower surfaces of the pivot bar and thus perform a guiding functio There is the same clamping mechanism adjacent each rail I4 of the lower ladder section 3 except that the release lever55 is provided on the left side only.

As stated, the coupling member is normally in locked position for swiveling of the ladder over a pivot tube. This ladder locking is automatically effected as follows. As the rails i4 carry the pivotally-mounted coupling members having the jaws 53 approach the pivot tube, the upper part of a downwardly sloping face portion 531 of the jaw 53 encounters the pivot tube S and, upon further approach f the rails I4, the sloping portion 531 of the jaw 53 causes the coupling member to swing on the shaft I, against the tendency of the spring 58, whereby eventually the nose 532 of the jaw 53 clears the pivot tube 6 and the spring 58 then snaps the jaw 53 into the clamping position on the pivot tube 5 shown in Figure 11. The clamping movement is limited by a stop lug 65 secured to the ladder rail I4. Furthermore, the stop lug 65 prevents the jaw part of the coupling member from swinging down too far, when the coupling member is disengaged from the pivot tube 6 and the ladder is backed off from the pivot tube 6. Such function of the stop lug 65 prevents the upper part of the jaw 53 from encountering the pivot tube 5, as the ladder approaches the pivot tube 6, and assures that this encountering of the pivot tube will be by the upper part of the downwardly sloping face portion 531 of the jaw 53 and thus effect the proper upward swinging of the jaw 53 as the ladder more nearly approaches the pivot tube 6.

When it is desired to unclamp the ladder from the pivot tube 6, the release lever 55 is pulled downwardly which causes the coupling member to be turned with the shaft 5 I, against the action of the spring 58, until the tail piece 54 of the coupling member strikes a lug B4 secured to the pivot tube 6. This amount of pivotal movement of the coupling member raises the jaw 53 thereof suiiiciently so that the nose 532 of the jaw 53 is turned to a position above the pivot bar E. This amount of movement ofthe release lever 55 has set up some moment so that continued 19 pulling upon the release lever causes the tail piece 54 of the coupling member to slide on the lug 4 which moves the ladder rearwardly away from the pivot tube 6 and thus backs the entire coupling mechanism away from the pivot tube S.

Certain other structural features of the improved ladder which are shown in the accompanying drawings are as follows:

Adjacently above the upper strut support I I of the upper ladder part 4 is pivotally mounted a jointed working platform structure 52 which, when the upper ladder section 4 is raised, automatically swings outwardly from said ladder section 4 to provide a support 6I for the workmen, this support 6I upon the lowering of the upper ladder section 4 striking the rungs of the lower ladder section 3 and folding up with the depending part 'I of the platform structure. For obtaining the level of the support 6I a longitudinal series of engageable notches are provided in the depending part of the platform structure. The platform structure 52 is made secure in any desired manner before the operator steps on the support 5|. In its opening and closing movements the support 6| slides upon an upper steel rung 2I1 of the upper ladder section 4.

At the top of the upper ladder section 4 a safety belt loop 7l is provided. Also, insulators 'l2 are provided upon the strut bars 22 for the lower ladder section 3 and the strut bars 23 for the upper ladder section 4.

What we claim is:

l. For use with a ladder, the sub-combination of a ladder pivot and clamping means comprising, in combination with a support, a pivot bar mountable on the support, a clamp pivotally mountable on the ladder and having a projecting jaw on one side of its pivotal mounting and a tail piece upon the opposite side, springs normally holding the jaw in clamping position on the pivot bar, means for unclamping the jaw, a lug on the bar limiting the unclamping movement of the clamp when the jaw thereof has been pivotally moved to unclamping position, the tail piece of the clamp riding on the lugs to push the ladder and the clamp away from the pivot bar upon further movement of the unclamping means.

2. The sub-combination of a ladder pivot and clamping means set forth in claim 1 in which a ladder guide is provided having flaring opposed surface portions moving closely adjacent opposed sides of the pivot bar as the ladder moves relatively to the bar.

HERMAN J. TROCHE. JAMES HOWARD HOLAN.

References Cited in the file of this patent UNITED STATES PATENTS Number Name Date 219,749 Marshall Sept. 16, 1879 1,899,742 Bay Feb. 28, 1933 1,952,761 Larsen Mar. 27, 1934 1,953,390 Bosch Apr. 3, 1934 2,035,537 Cowan et al Mar. 31, 1936 2,245,481 Kiley et al June 10, 1941

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