US1470139A - Aerial extension ladder - Google Patents

Description

Oct. 9, 1923.

R. S. BOLGER AERIAL EXTENSION LADDER Filed Aug. 22. 1921 4 Sheets-Sheet 1 m fi c 95 h Gwen way .l pml y Q E Oct. 9 1923. 1,470,139

RQS. BOLGER AERIAL EXTENSION LADDER Filed Aug-- 22. 1921 4 Sheets-Sheet 2 gmvewtoz i W 3 ffioe @351 his awe Imago Oct. 9 1923. 1,470,139 R. s. BOLGER AERIAL EXTENSION LADDER Filed Aug. 22. 1921' 4 Sheets-Sheet 5 Oct. 9 1923.

A. w t 0 w 7 a. 4 m 1 9 av h s 4 R s BOLGER AERIAL EXTENSION LADDER Filed Aug. 22.1921

\ liii Patented Oct. 9, 1923.

um-ree stares PATENT oFFic ROBERT s. BOLGER, or New Yemen. sssrenor. ro-rnrnaim'rronni. MOTOR 001v:-

VPANY, or New vYonK, n. Y.

AERIAL A CORPORATION. OF DELAWARE. V

z zrnnsron LADDER.

Application filed August 22, 1921. Serial No. 494,130.

Y '0 all whom it may concern:

Be itknownthat l, item-1R1 S. BoLsER, a citizen of the United $ta-tes,residing in the h I l t- 'f tl 't f New coiougii oriian 1a an, 7 1e 01 y 0 York, in the State of N ew I ork, have invented certain new and useful Improvements in rierial Extension Ladders, of which thefol lowing is specification, reference being had to the accompanying drawings, forming a part hereof. I e I This invention relates'to aerial extension ladders of a type which. is very wel known,

broadly speaking, and'has for its principal object to improve such laddersin certain respects, as will appear more particularly hereinafter. y I p The type of ladder to which the iinprove vments are particularly applicable is one in which spring plungers serve to raise the ladder while pull-down cranks are employed to return the ladder to its bed against the action of the springs. In such ladders mechanism is employed for their traverse present 'iinprovements'have to do principally with one or more of the elements enu merated above and seek to bring them into a relationship which is more effective in operation and more convenient for in anipulation bya single attendant.

Reference is now to be had to t panying drawings for detailed d of asuitahle embodiment of the various iiuproved features, in which drawings- Figure 1 is a view in side elevation of the r f improved ladder and controlling mechanism, v Figure 2 is a view in plan thereor, the

bed ladder and its supports beir emoved a L in the interest of clearness.

Figure8 is a view 1n end elevation ,of much of the construct1on as'illustrated v Figure 1.

I in

Figure l is a fragmentary detail view section through the turn-table taken on the plane indicated by the line li of Figure 2 connections described.

in I

and looking in the direction ofthe arrows.

Figure 5 is a detail view in vertical section of the controlling worm shaft taken on the plane indicated by the line 55 of Figure 2 and looking in the direction of the arrows.

' Figure 6 is a view in transverse section through the worm shafttaken on the plane indicated by the line 66 of Figure 2 and looking in the direction of the arrows.

Figure 7 is a fragmentary-detail view in section on the line 77, Fig. 2 of the mechanism for operating the turn-table and the centering lock therefor.

igures 8 and 9 are detail views in horizontal section through the operating shaft for the turn-table showing the improved lock mechanism associated therewith and taken on theplanes indicated by the respective lines 88 and 99 of Figure l and looking in the direction of the arrows.

Figure 10 is a view in side elevation of the hand operated detent for the centering lock. Thebed ladder a is supportedpivotally at a on A-frames a secured at opposite sides of a rotatable turntable b on which all the improved mechanism is mounted. The ladder (4 has extending longitudinally thereof on its upper and lower sides truss rods, 0, c which pass around its ends and are inter connected so that bending stresses on the ladder are transmitted throughout the length of such rods. The ladder or has secured thereto at each side a frame (Z which is connected to'the ladder at opposite sides of the pivot a so that in the elevating of the ladder it is subjected to an elevating thrust and an elevatin )ull. The lower end of the frame (Z (and a similar frame at the opposite side of the ladder) is pivotally connected to a pull rod 65 whichis pivoted to a cross head (Z The cross head has connected to it spring-pressed plungers d slidable in horizontal cylinders which are mounted fixedly on the turn-table b. The springs d within the cylinders (5* have their elevating efforts transmitted to the bed ladderby the The spiingpressed plungers (Z are heldin retracted position by means of a latch D manually operated by means oflevers D D- which co-operate with the cross head (Z It is necessary, of

course, to regulate the speed with-which the ladder is elevated under the influence of the by means of a hand lever e;

p s 7 h i 19 y means f a ak band whiehcooperates with a; brake drum 7", secured to a worm shaft f. Operation of the brake is effected manually on the turn-table and operatively connected through the element e ,,t0 the brake band. The Worm shaft f is journaled rotatably on the turn-table,butisheid against axial movement thereon by means of suitable bearings, one of which is indicated at f9.- Qn-the Worm shaft 7' is mounted a nut 9., w ich, Whenthe brake a: is e a ed, ca travel freely alongtheworm shaft. The

:nut g is connected atopposite sides through trunnions g with pull rods g which areconnee-ted te the cross head d--. From this description it will be evident that the rate of elevating. the ladder under the influence of the springs cLFmay be controlled by thehand brakee. which. Will limit the speed of rota.- tion offtheworrn: shaftlf as the nut g travelse along it.

When the bed ladder a, is. resting in its cradlei on the. vehicle, the turn-table b will be locked; in centered position by means of a; plunger lock it which is carried Q11 the'turni-table and adapted to enter an Opening i in the stationary bed ring 2' on which the turn-table is rotatably mounted through-balls *2' and 2'. The centering lock .lz is'sna'ppedautomatically into the opening 2', when the turn-table is centered, by means of 5a springv it". vVV-hen.theturn-table1s to be traversed,-howevr, the centering lock must be withdrawn against the action of the spring h, by means of improved hand-operatedldevices shown most clearly in Figures Sland 10.. On a stationarypart of the turntable, indicated asa vertical. tube Z0, is. pivoted.,.anfo rk Theotherend of this elementis 'forhe'd and engages with a collarh carried byithe plunger lock h. A bifurcated handle 71: engages over the outer end of the element is :and; is pivoted thereto. at

: t lie handle 1: is elevated about the pivot of shoulder- ,l i.

theforltk until the arms Z1 ride over the be'found that the. plunger 72, has been entire- -.ly withdrawn from its entering recess e and is vloekedrin elevated position: by engagement of thearms k wwltll theshoulder k9.

la is rocked about its pivot so as to clear the carried Then in this relation it will This relatimr'Will bemaintained until thehandle arms from the shoulder Z66. 'Thereupon the spring h will become effective to force the plunger it into its recess 2'. i

The mechanism for traversing the turntable is comparatively simple.- .The bed ring 2" has cut on its inner periphery an internal spur gear i 'The turn-table Z) has journaledtherein a vertical rotatable shaft Z) on the lower end of which is carried a pin ion Z2 meshed with the internal gear 71 An operating wheel 5 is carried at the upper end of the shaft Z). Rotation of the shaft 5 with its pinion b will serve to rotate the tuna-table to any desired angular position. in order to lock it in any desired predetermined angular position, simple and improved devices are mounted on the v'ertical column Zc through which the shaft Z) passes. This position lockis made up from a split section of the tube 711 wlnchis 61 111 braced by a split ring is adapted to be compresscdby operation of a hand operated nut 14: threaded on to a bolt 1b" which passes through the free ends of the split nut it. By

tightening the hand operated ring if the spllt nut is Wlll be compressed and bind the tube 7: on the operating shaft b so to prevent furth'er rotation thereof. This locks the turn-table in adjusted angular position.

W it-h the bed ladder a raised it is necessary to depress it either for the purpose of adjust-ing it against the building or for lowering it to its cradle. Suitable hand operated pull-down mechanism-is provided in the improved construction. 0n the turn-table is journaled a worm shaft Z, to theends of which may be applied hand cranks Z for convenient actuation of the shaft. I The worn'i formed preferably adjacent to the mid-section of the shaft 15 meshes with.

a worm vgear m on. a stub shaft on which is also supported on the turn-table The inner end of. the stub shaft viii," carries one section of any suitable form of clutch, shown in the drawings as a simple dog clutch men'iber, in/ In proximity to the stub shaft m is found one end of the worm shaft f on the end of which is feathered the other member i of a dog clutch which,'by means ofa hand lever f i'nay' he slid into engage ment with the dog clutch member m In this Way the worm shaft f may be connected operatively and at will to the worm shaft 1. Rotationof the worm shaft Z, when the the ladder. The irreversible worm connection. between the worm Z andtheworrrr gear 222 insures a positive 'lockingof the parts in all positions; against angular inoveni ent. Such relation. also permits the nicest degree of the adjustment of the angular position of the bedwladder a When in the It will be appreciated that "with the fulcrum a of the bed ladder a so near one end, slight movement of the lower end of the ladder is greatly multiplied at the upper end. For this reason, a distinct improvement is realized by providing for a very fine degree of movement through the worm Z and worm wheel at. When the ladder is thus nicely adjusted to its proper angular position, it will beheld there positively by reason of the interengaging worm Z and worm wheel: m. When the clutch elements 7, m are disengaged the'worm shaft f will in convenient reach of a single attendant,

standing thereon. He'-'may, for instance, readily operate the hand wheel 6 to traverse the turn-table; he may manipulate both the lock devices'for centering or for position, through the nut or the handle 7J he may control, the rate of elevating through the brake handle 6 and he may throw in the dog clutch f by means of the lever 7, whenever the ladder is to be pulled down or locked in predetermined an gular position. This organization of parts, by which such convenient central control is placed under the handof a single attendant, insures quick and effective manipulation of the ladder operating mechanism. Further, the improvements in the component elements entering into this organization are of a substantial and important character in advancing the art. I

What I claim is:

1. In combination with an aerial extension ladder, a' turn-table, control mechanism for i the ladder mounted on the turn-table and comprising means to traverse the turn-table, means to elevate the ladder, means to lock the turntable in centered position, means to lockthe turn-table in predetermined. adjusted angular position, means to control the rate of elevating the ladder, means to lock the ladder in predeterminedangular position, and hand operated devices for actuat to said worm wheel, and means operatively connecting said worm wheel with the first worm shaft for the purpose of locking the parts against angular movement.

3. In combination with an aerial extension ladder, means on which the ladder is pivotally mounted and pull-down mechanism for said ladder including a worm and worm wheel in irreversible relation for the purpose of transmitting a pull-down effort to the ladder while locking the parts against relative angular movement.

4. In combination with an aerial extension ladder, means to support it pivotally, pulldown mechanism including a worm shaft, a nut mounted to travel on the worm of said shaft, means connecting the nut with the ladder in pull-down relation, an independent worm shaft, pull d'own cranks for actuating the same, a worm wheel in mesh with the worm on the last named shaft, and a clutch operatively interposed between said worm wheel and the first named worm shaft for operatively connecting and disconnecting the two.

In an aerial extension ladder, means to support it pivotally, power operated devices connected operatively to the ladder for elevating it, a worm shaft, a nut mounted to travel on the shaft, means to connect the nut to the ladder and a brake operatively associated with said worm shaft to control the rate of elevating the ladder.

6. In an aerial extension ladder, a sup porting bed plate therefor, a turn-table mounted rotatably on the bed plate, a springpressed position lock carried with the turntable and adapted to engage the plate to hold the turn-table in centered position, a bracket on the turntable through which the lock passes and a bifurcated handle engaging the lock and having a toe co-operating with the bracket to hold the lock in released position against the action of its spring.

In an aerial extension ladder, asupporting bed, a turn-table rotatable thereon, a centering lock comprising a vertical plunger carried on the turn-table and adapted to engage the supporting bed and hand operated devicesto release the plunger including a pivoted fork ra bifurcated handle pi oted to the fork and engaged with the plunger and a toe carried with the bifurcated handle and co-operating with a fixed shoulder carried with the turn-table.

This specification signed this 16th day of August, A. D. 1921.

ROBERT s. 'BOLGER.

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