US1899742A - Extension ladder - Google Patents

Description

Feb. 28, 1933. c. A. BAY

EXTENSION LADDER Filed May 29, 1930 6 Sheets-Sheet l \E RT NN Qx Y E N R. O T T A Feb. 28, 1933. c A Y 1,899,742

EXTENSION LADDER Filed May 29, 1930 6 Sheets-Sheet 2 ATTORNEY Feb. 28, 1933.

C. A. BAY

EXTENSION LADDER Filed May 29, 1930 6 Sheets-Sheeii s ATTQRNE Feb. 28, 1933. c. A. BAY

EXTENSION LADDER Filed May 29, 1930 6 Sheets-Sheet 4 VEN ATTORNEY Q Feb. 28, 1933. c. A. BAY

EXTENSION LADDER Filed May -29, 1930 6 Sheets-Sheet 5 ,3 eel 48 I 4 1% 44 47 47 4 3 q z 5a :34 f J. '2;

ATTORNEY Feb. 28, 1933.

C. A. BAY

EXTENSION LADDER Filed May 29, 1930 6 Sheets-Sheet 6 l VENTORQ Bfijifzlwg made longer than 'tion the plate 9 At each side of the frame a member 6 extends'upwa-rdly and rearwardlyfrom the for-' ward end, of the corresponding side member 3 and a member 7 extends upwardly and for- Wardly from the rearward end of such memher 3. Such members 6' and? at each side of the framelare connected with the base members 3 and f1 by means including corner plates 8 and their inclination is such that their up: per ends 7 nected by a plate 9 which'is utilized to sup are adjacent and can easily be conport the extension ladder at one side,

The side frames unectedzwiththe corresponding members 6 and, 7 at points intermediate their ends and atthegfront'byg-diagonalzbraces 11 and horporting frame'imayn metal angles and suitable connections.

,bynuts which are tightened parts firmlytogether.

'izontal,n'le'n'lbers 12 connected with a generalv 7 rod 29, and nuts threaded,on the ends of .said rods.

ly central plate13andiwiththe members 6'.

.Thei rearside of the frame leis-left open betweenthe members-,7 to receive one end of themembers 7so, as to posito the 1 rear of the'middle' pointsof the side members 3 and thereby pro vide more effective support for aladder which is inclined upwardly. and forwardly when in use. As illustrated inthe drawings, the sup;

Convement y be bum 0 bodimentof the lnventionthisresult is at tained'by providing each of such rungs'at It is of importance to provide not only a frame whichcan readily be inserted in a vehiclev body but also suitable means for connecting it with said body. Accordingto the illustrative form of the apparatus, this result is. attained by placing planks or joists 1 1 on the :floor15 of the. body 2 to receive thereon the sides of the base of thesupporting frame and by securing the frame to the'floor 15 by suitable-means suchas hooks 16 engaging the frontgend'member 4 vat points adjacent to the inner edges of the joists and passing throughntheifioor 15,, and bolts 17 passing downwardly through the corner plates 5 at the rear of theframe. The hooks '16 are tightened and held in position by nuts18 threaded on the lower ends ofthe hooks and sep arated from the floor15 by suitable washers.- lAswill be brought outmore clearly hereinafter,

the-tendency to lift at therear end of'thef frame is greater than at the front end.': As

' a result of this condition, it is found desirable to reinforce the floor 15rby ametal stripf19 engaging the lowerside therof- The bolts 17rpass through said strip and are engaged to draw the' The extension ladder comprisesa mainor' lower-section 21 pivotally supported'by the plates 9 at the topof the main frame, and a similar shiftable section 21a-slidably mounted formed by the members 6' and 7 at opposite sides of the main frame are in said main portion 21; When the ladder is collapsed, the sections are in what maybe called nested relation. The section 21, taken as a whole, is triangularin cross section and includes a part which in itself is a complete ladder comprising side-pieces 22 and cross.- pieces or rungs 23, anda part, of V-shaped cross section comprising three longitudinal Th'e'side-pieces 22 and the adjacent side'- '7 pieces 2 1, although at substantially the same distance apart throughout their lengths are in angular, relation with respect to each-0th er and are -secured together at points, core responding witlr the location of the rungs 23, by means 'including bent plates ;27fjen-f gaging the outer faces of side-pieces '22 an d V 2 r e p n y bent Pl es-( 218 engages Y ingthe inner faces of sidepieces- 22 and 2 1,-

28 are connected ,with p the, corresponding members 24 by suitable means such as bolts 3e and meat. The rungs 23 should be held 7,

against turningJa nd in the illustrated emeach of Iitsfends with a'pin-36 to enter a cor responding opening37 in the 'c'orresponding plate 28. Preferablythe-rungs a'rel made of hard fibre; g 1" I 1 v I The rungs 25=of they-portion are'held in' position between the longitudinal members 24 by rods 38 extending axiallythrough the rungs and nuts 39 threadedjon the ends vof theerods. "The rods 38 also pass through platesjsimilarto plates 27 Qand 28"whicl1 are bolted at their other'endsfto the side pieces 22a. Ordinarily no provisionto prevent turning; of the rungs 25'i's necessary;

The ladder section 21a is constructed in the same generalfmanner' 'as the ladder section and, for conveniencefthe partsof the section 21a corresponding with parts of reference numerals but with the; letteria associa t ed therewith. The main" difference be tweenithe sections or.

sides' in the; smaller cross section of w-the'secouter edges with strips 40 whichpre vent en gagement. of the corresponding rod: ends and ladders 21 and 21d re thesect'ion', 21 will bedesignate d by the same 2 nuts with the rungs 25;} ln thisfconnection,

it should'be noted see Figs; 12 and 13)" that the-construction ofth "ladder? sections" 21 and 21a at the sides where the rungs'23v and 23a are located is such as to avoid any interference with the sliding of the section 21a in the section 21. The rungs 23 can be engaged only by straight sides of the members 222 and the rungs 25 can be engaged only by straight sides of the members 24a in addition to the strips 40. V

The main ladder section or ladder 21 may be pivotally mounted on the plates 9 of the supporting frame in a manner shown most clearly in Fig. 12. A hollow rung 42 of metal, provided at its ends with plates or flanges 43, is interposed between the side pieces 22 at the proper location for the pivotal axis and the plates 43 which are in tegral with the rung 42 members 22 by bolts 44 passing through openings 45 in the plates 43, through the members v22, and through openings 46 in plates 47 at the outer sides of the members 22, the ends of the bolts being engaged by nuts 48. Preferably the plates 43 and 47 extend beyond the edges of the members 22 towards-the members 24 and are bent so as to engage the same at the sides and are fastened with a bolt similar to 44. Blocks or spacers 49 are interposed between the plates 47 and the plates 9 of the supporting frame and the pivotal connection is completed by a bolt 50 passing through the plates 9, the blocks 49, the plates 43 and 47, the side pieces 22 and the hollow rung 42. The bolt is secured in position by means of nut 51 threaded on the bolt and engaging the outer side of a washer.

The bolt 50, which constitutes the pivot for the ladder section 21, is located near the lower or rear edges of the members 22 and at such a position longitudinally thereof that the rear or lower end of the ladder section may be swung into the supporting frame. In order to obtain a sufficient effective length for the ladder section 21 and for other reasons, it is generally desirable to have the part of the section or portion 21 at the front of the pivot of greater length than the part at the rear of the pivot.

The "over-balancing to the front of the pivot resulting from the position of the pivot along the side-pieces 22 and from the shiftable ladder section 21a mounted in the main portion, tends to cause the ladder'to swing forwardly; and when the ladder is not in use it is supported by suitable means at the front of the truck. In order that the side-pieces 22 may be of great strength without undue increase in weight, they are of considerable depth adjacent to the pivot but decrease in depth toward their ends.

Referring to Figs. 1 and 16, the truck is provided at opposite sides with uprights 53 which may rest on the running boards and be attached at a higher level with the front of a drivers cab, and a cross member or beam 54 connecting the upper ends of said up are secured to the.

rights. The intermediate longitudinal member 24 of the main ladder section 21 seat? itself in a notch at the upper side of a bloc As here shown the block or member is supported in a socket member 56a secured to the cross member 54' at the front side thereof;

Although the weight of hold it in the seat in the'block 55, it is desirable to provide means for preventing the ladder from jumping up from the seat. For this purpose, there are provided at the rear side of the cross member 54 two levers 56Ipivoted at the same level on pivots 57 and connected by a link 58pivoted to oneof the levers 56 pivot 57 and to the other lever at a point above the corresponding pivot 57, so that the levers swing outwardly and inwardly together. The upper ends of the levers 56 are bent inwardly and are provided at their inner sides with fiat portions or plates 59 which are so inclined as to engage and lie along the inner surfaces of the: 24s,: as indicated in Fig. 16.

The levers 56are yieldably urged together to engage the ladder and hold it down on the seat in the block 55. As here shown, a link 60 is pivotally connected at one endwith a. yoke 61 embracing one of the levers 56 and connected therewith by a pivot 62, and at the other end with a handle 63 from the link at a right angle. At an intermediate point the link passes through a bracket 64 fixed onthe beam 54 and the urging of the levers '56 to clamping position -is eifectedfby means of a spring 65 interposed between the yoke 61 and the bracket 64. The yoke 61 may bedrawnoutwardly by means of the handle 63 to release the ladder and then turned to permit the handle 63 to rest against the outer side of the corresponding upright 53 and prevent return of the link under the rug ing of the spring. Accidental opening of the levers 56 and consequent release of the ladder is prevented by engagement of the link with a bracket 65a secured {to the cross member 54, the handle63 being in its Fig. 16positi-on. Also the bracket 65a keeps the handle '63 from slipping along the upright when in its locking position.

It wouldbe undesirable tostart the truck when the ladder is raised or-even when it is unlocked. To guard against starting under such conditions, one of the arms or levers 56 is connected by means of a link 66 with an arm 67 of a switch 68 in a controlling circuit such as an ignition circuit,so'that when thearms 56 are thrown apart the circuit is broken at that turned to holding closed at that point.

WV hen the ladder is :to be raised, the handle 63 is drawn out to release the ladder and placed in engagement with the outer face of position the circuit is 55 supported by the cross member 54.

the ladder tends to at a point below the corresponding intermediate member extending point andw'hen they are re I Vid-ed with a suitable handle,

'rope 81 extending the corresponding upright to prevent return of the holding members to holding position. The forward part of the, ladder is then swung upwardly as by pulling down on the rear part thereof and the rear end of the. main section21 is swung, into the main frame and secured in proper position therein by suitable means which will nowbe described.

Mounted at the lower end of the main ladder section 21 and at the outer side of each member 22 near. the corresponding .member 24, is a latching bolt 7 O of which the lower end projects through an opening 71 in a flange 72 or the like projecting from the bottom of'a socket or tip 73 receiving the lower ends of adjacent side- pieces 22 and 24 and secured thereto in any suitable manner. Each bolt is also guided by devices 74 (Fig.

11), each comprising a central plate portion -to be secured tothe corresponding members 22 and 24 in any suitable manner, as by means of bolts or screws passing through holes 75, and at each side of such central portion with split eyes 76 to receive the-bolt, such eyes being closed to the desired extent by bolts 77 and nuts threaded thereon.

Each bolt is urged downwardly by suitable means, such as a spring 78 surrounding the bolt and interposed between the lower side of one of said devices 74 and a collar 79. The downward movement of each of the bolts may be limited in any suitable manner,

as by means of a stop 80 located thereon in a position to engage the member or plate 72, and lifting of the bolt may, conveniently be effected by meansof a flexible member or from a fixed connection with the ladder portion 21 downwardly and through an eye 82 in the upper end of'the bolt, upwardly and over a pulley 83 fixed on the ladder portion or section 21, and then downwardly, the end of the rope being prosuch asa ring When the lower end of the ladde is swung downwardly and forwardly into the main frame, the lower ends of the bolts70 ride up on the downwardly inclined forward ends of fixed plates 85 and along the upper surfaces of the plates until they drop into suitably positioned openings 86 in said plates. 7 In some cases it may be necessary to pull down on the rings 84 to lift thebolts 70 high enough to ride over the plates 85. Supportfor these plates is provided by across member 87 attached at: opposite ends to the posts or members 7 at the rear of the mainframe and also by diagonal members 88 supported attheir rear ends on'the member, 87 and at their for-. ward ends on the cross member 4 at the base of the main frame. At the crossing of the members 88, there is secured to said members at the lower sides thereof, a plate 89 having a downwardly inclined rearv end so that the lower end of the intermediate member 24.will readily pass over the top thereof into the V-shaped opening between the members 88. In this connection, it should be noted that immediately to the front of the plates 85 the diagonals 88 are turned up-' wardlyso that the lower end of the intermediate member 24, while passing freely over rest onor come the plate 89 and the cross member 87, will close to the upper surface of therefore will be sure opening between the members 88 (see Fig. 7)

To support the upper ladder section 21a on the lower section 21 in any desired position, the upper section is provided at opposite sides with devices 90, hereshown in the form of hooks pivoted on the section21a and adapted to hook over rungs 23 on the main ladder section 21. The upper ends of the hooks are shaped so as to be cammed back by the rungs 23 of the ladder portion. raised ust above a rung they will engage the rung If the hooks are and hold the ladder section 21a in raised position; but if the. hooks are raised high enough above a rung ordinarily be positioned. The. hooks and l associated parts may besubstantially the same as devices heretofore in use for purposes. i

The raising and lowering of the ladder section'21a may conveniently be effected by means of flexible connectors or ropes 92 fixedly attached to the members 22 near their upper ends and looped downwardly around pulleys 93 attached 94 attached to the members 22 at points toenter said V-shaped.

during the upwardmovement 23 andthen lowered, v

such

7 to the members22a near their lower ends, and upwardly over pulleys spaced downwardly to some extent from their upper ends. The ropes 92 after being looped over the pulleys 94 and extended downwardly far enough to avoid interference with the lowering of the ladder section 21a, areprefer ably combined at a convenient point into a single member handling.

To add to the safety of operation, 'provision is made of means to, indicate whether the bolts 70 are securely latched to the plates 85. As here shown, such means include switches 96 mounted below theplates 85 so as to be closed by the bolts 70r whenthe y pass downwardly into the openings 86 insuch plates, and a circuit 97 containing the switches" 96, a suitable current source 98 and lamps 99 mounted on the rear faces of legs 7 at the rear of the main frame. Preferably 95 for convenience in this circuit is grounded. The circuit will be closed only when both bolts 7 0am in latching position and at the time both lamps 99 will be lighted.

As shown in Fig. 8, each switch 96 is 70 into engagement with another Contact 103'. The plate 102 of insulating material is suspended from the plate 85 in a suitable manner and the two contacts 101 and 103 are connected through the plate 102 with the ends of conductors forming part of the circuit 97.

Preferably the upper leg of each contact 101 .is provided with a block 104 of insulating material to protect it against wear which would otherwise result from engagement by the bolt 70. a

Recapitulating briefly, the operation is as follows: During transportation of the apparatus to the desired location, the parts are located as indicated in Fig. 1. When the vehicle has been placed in the proper position, the handle 63 is pulled to the right to separate the clamping levers 56 and release the ladder sections 21- and 21a at the forward part of the vehicle or truck, and is then turned into position to engagethe outer side of the corresponding upright 53 and prevent return of the link 60 under the action of the springand the consequent return of the clamping levers to latching'position. The movement of the handle 63 to the right also acts to open the switch 68 and thereby prevent starting of the motor of the truck.

Then the ladder structure is swung about,

the pivot, or bolt 50 to raise the forward part and depress the rearward part until the latch? ing bolts 70 ride over the fixed plates and enter the openings 86, thus securingthe main section 21 in position for use; Proper latching of the bolts 70 to the plates results in closing both of the switches 96 and lighting both of the lamps 99. 'It will be seen that lighting of these lamps indicates eii'ective latching action by the bolts 70. a

At this time, the hooks on the shiftable section 21a are in engagement with the rung 23 which is the third from the bottom, and

the lower ends of-the two ladder sections 21' and 21a are in adjacent'positions. The shift able ladder section 21a may then be raised to the desired height by means of theflexible members or ropes 92 and 95. In such'upward movement, the hooks 90 ride across the successive rungs -23 and,. if the section 21a raised no higher the hooks will engage that rung and support thelad' however, be lowered at any timeby; raising it the parts'restored to theirFig. l transportation to other points. H

ng from the spirit and scope of p the invenf vand means. operable v der portion in such raised posltion. The ladder section 210; can,

to. prevent the latter from'engaging-any of said rungs.

WVh'en the use-Jot the. ladder is completed, the various'steps are'reversed and positions'for Obviously the extension ladder may-be madeup df'moreeth-an two ladder sections. It should also. be understood that a various (changes maybe made in the construction and arrangement of parts and that certain parts may be used without others without depart tion. I e clairnz combinationwith asupporting frame, of a ladder pivoted thereonyladder latching means to hold said-ladder in raised position,

ing means to indicate when latching is effected. v

2 In apparatus of the class described,

80 91'. In apparatus o'ftthe class describ g is ladder andmovable longitudinally thereof,

and a fixed plate having an opening to receive said downwardly urged'member and having a portion of its uppersurface inclinedso that when the ladder is swung to raised position the downwardly urged member will ride up the inclined portion of the upper surface of said plate and enter 'said'opening. I

3. In apparatus of the class described,'thev combination with supporting means, of a:

ladder pivoted thereon, longitudinally-movable latches mounted on said ladder at opposite] sides thereof, stationary members having openings-to receive said latches, ing means including an electric and indicatcircuit having switches therein] n position to be en'- gaged by said latches when the latter move to'latching position.

4; .Inapparatus of the class described, the

each side'ofthe ladder, and a means and two switchesinseriesin saidvcircult and controllable bylthe corresponding latching devices.

[5. In, apparatusofthe class described, the g combination with a motor truck 7 having a controlling circuit, of a switch in for-opening said switch when such holding means is released 1 material surrounding thepassages through,

longitudinally of combination with supporting means, of a ladder pivoted thereon,'latching devices for I circuit includ ing a light on each side of said supporting said ,circuit, a ladder pivotedfon said truck, means for holding said ladder in lowered position, by such holding means and means controlled by said ladder latch- 8 j I V rungs and said posed between longitudinal piece spaced 7. In a ladder structure, the combination with a ladderproper comprising two side pieces and-rungs connectingthe same; a rear portion comprising longitudinal pieces adjacent to said sidepieces, an intermediate the ladder proper andtwoseries of rungs each series connecting said intermediate 1ongitudinal piece with the other longitudinal pieces, respectively; and means'for securing. sald side pieces and the correspond1ng1ong1-- tudinal pieces together."

extending through said:

rearwardly from CHARLESA, BAY.

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