US2245481A - Portable aerial ladder - Google Patents

Description

June 10, 1941. A. J. KlLEY r:rAL

PORTABLE AERIAL LADDER Filed Na 5, 193a :5 Sheets-Sheet 1 H HHEMHHU June 10, 1941.

3 Sheets-Sheet 2 f W 9 m .j-ff

Patented June 10, 1941 PORTABLE. AERIAL LADDER Albert J. Kiley, Belmont, and John T. Kiley, Ar-

lington, Mass, assignors to James A. Kiley 00., .Somerville, Mass., a corporation of Massachusetts Application November 5, 1938, Serial No. 238,956

2 Claims.

This invention relates toaerial ladders such as are mounted on vehicles and usedin the repairing. and servicing of wire and lighting. equipment elevated above the highway, in tree trimming, fruit picking, and in various other connections. It has particular relation to the device of this sort illustrated in our Patent No. 2,116,470 granted May 3, 1938,in which patent is disclosed a ladder combined with a self-contained erecting, adjusting, and carrying unit which can be applied quickly and easily to the floor, deck, or body of any vehicle without the need for any permanently attached structure built onto the vehicle, and which unit can be easily and quickly removed from the vehicle when not needed, whereby the general utility of the vehicle for customary load-carrying purposes, when not in immediate use as a mobile ladder base, is not impaired. 7'

The object of the present invention is to im-' prove the structure of our above patent in two main particulars, the first being. to provide complete control of all the manipulations of the ladder by one man while'standing at a single control point within the vehicle on which the aerial ladder is mounted. Hitherto in all constructions of portable aerial ladders with which we are acquainted it has always been necessary for the operator of the ladder to get out of the vehicle and go to a point remote from the ladder-extending, tilting, and swinging controls in order to unfasten the keepers, clips, detents, or hold-downs necessarily employed to hold the more remote portions of the ladder firmly in place on its support on the vehicle during transit. The inconvenience, delay, and danger incident to this operation, especially inwork on overhead wires or light servicing on heavily traveled highways, particularly where the op:

erator has been compelled to stand at theleft hand side of the vehicle in so doing, has been found in commercial experience with our device to leave room for improvement. Therefore, to.

improve the structure in this respect, provision has been made to enable the operator to release the ladder from the retaining clips or hold-1 down devices, in making it ready for use, and to re-engage the ladderwith such hold-down devices subsequent to use, from the sameposition- By providing remote control forthe manipulation of the ladder is now made possible from within the vehicle, and by a single operator, without the need to set foot on the ground and practically without moving out of his tracks.

The second .main particular in which it is aimed to improve the patented structure and other known portable aerial ladders relates to increasing the ease and accuracy of locating the top or other elevated portion of the extended ladder in the desired relation to the wires,lights, portions of the tree, or other elevated object to which access is desired by means of the ladder. To the best of our knowledge, no prior structure has provided an extension ladder which can be accurately adjusted in three dimensions by one man when in its fully extended relation and when inclined as much as to the vertical. Hitherto, it has always been necessary to retract the extensible upper section of the ladder in order to reduce the unfavorable leverage exercised by the weight of the ladder sufficiently to enable one man to lift the free end of the ladder when slanted at an angle of 45 or more to the vertical. Not only does this result in loss of time and added effort in retracting and again extending the ladder, but it is frequently necessary to perform the operation several times because of the difficulty in guessing where the retractedtop end of the extension portion of the ladder will be when again extended after adjustment. Further, it was not always convenient or possible for the single operator, even when lowering the ladder in extended relation, to watchthe course of the top end of the ladder while working the controls, a part of this difliculty being the concentration incident to the heavy physical effort involved in working the angular elevation. gear itself. Thus itpwas found. to be very difficult to bend over and rotatethe hand wheel which in our prior patentedstructure"revolves the jack screw in one direction to allow the ladder-supporting standard'to tip to lower' the ladders free end and converselyto bring back the standard to elevate such end of the ladder, while watching the position'of the top end of the ladder at all times to note its position with regard to other objects. Additionally, another source of dinic'ulty has been therelatively narrow space available between the side Walls of the familiarutility bodiesgwith which these portable aerial ladders are commonly combined to form service trucks for telephone and electric companies, which want of space leaves the operator no place to stand between the foot of the ladder and the stands alongside of the ladder in an erect posi-jf tion whence he can observe clearly andeasily at. all times the location of the upperextremity of the ladder; preferably, also, springs are provided,

to counter-balance a part of the load of 'the But, in contrast to the prior structure, new and improved means is provided to drive the jackscrew in place of the hand wheel previously employed. The top end of jack-screw 2| is fitted within and pinned to one element 4| of a universal joint 43 of which the other element 45 is correspondingly afiixed to a square stub-shaft 41, to the end of which is welded a square sleeve 49, in which slides freely a closely fitting square shaft I, the upper end of which is fixed within of which the upper element is attached and ladder which resists the lifting of the ladder into more erect relation. Additionally, these results are attained while always keeping the foot of the ladder under complete and powerful mechanical control so that it cannot get away T to crush the operator between its foot and the side-wall or other part of the vehicle body.

Other aims of the invention and their manner of attainment are as will be made plain hereinafter.

An illustrative embodiment of the invention is shown in the accompanying drawings in which:

Fig. l is a side elevation of a motor truck with utility body and a portable aerial ladder of the type shown in the aforesaid patent installed therein, showing the devices of the invention applied thereto.

Fig.2 is a vertical section on line 2-2 of Fig. l on a somewhat enlarged scale, showing the improved elevating gear and the counter-balance springs.

Fig. 3 is a plan view in section on line 33 of Fig. 2' showing details of the elevating gear.

Fig. 4 is a plan View on an enlarged scale of the ladder rack which extends forward over the cab of the vehicle in Fig. 1, showing the improved ladder clips and the remote controls therefor.

Fig. 5 is a side elevation of the same.

Fig. 6 is a section on line 66 of Fig. 4.

The motor vehicle or truck of Fig. 1 has a typical utility body, which as shown in Fig. 2 comprises a number of lockers or compartments I for tools and materials formed in connection with spaced vertical side walls 3 located at each longitudinal side ofa floor or platform 5 to which is detachably afiixed at I the base plate 9 of a portable aerial ladder made as shown in our prior patent. Herein, as there, the extension ladder II is erected from its solid-line carrying position of Fig. 1 to that indicated in dotted lines in such figure by swinging it about pivot I3 at the top ofstandard I5, and its foot is locked down against the inclined side of such standard by spring clamps I1 and additional safety bolts. the entire standard being allowed to tilt about a horizontal axis at I9 to lower the free extremity of the ladder, and being moved reversely to elevate such extremity of the ladder by means of a jack-screw 2| having an integral head 23 on its lower end which as before rotates freely in a bushing 25 swinging on trunnions 2'! in lugs 29 fixed to the under surface of turn-table 3| on which the standard I5 is pivotally mounted. Also as before, the jack-screw passes through a pivot nut 33 swiveling on trunnions 35 in suitable bearings 31 fixed on brackets fixed within the channel of a transverse channel iron 39 forming a part of the foot of swinging standard I5.

pinned to a second stub-shaft 55 pinned within the hub of a bevel gear 51, the whole providing a flexible drive-shaft. Supporting bearings are provided for stub-shaft 55, one of these being formed through the depressed central portion of .a strap '59 extending across the width of the standard I5 and attached at its extremities by bOltSfBI to angle irons 63 bolted to each pair of legs of standard, I5. The other bearing is formed in a strap 65 bolted to strap 59 to extend over bevel gear 51, stub-shaft 55 having a head 61 which overlies the strap 65. A small bevel pinion 69 engaging with gear 51, preferably with about a 3-to-1 ratio, is fixed on one end of a shaft II' rotating in bearings I3 on strap 59, the other end of shaft II having affixed thereto a hand crank I5. A simple cylindrical or cup-shaped gear-cover (not shown) is placed over the bevel gears when in use.

Additionally, to reduce the physical effort involved in tipping the standard I5 and the erected ladder while held down thereto by clamps I'I, especially when the upper section of the ladder has been fully extended, counter-balance springs in the form of contracting coil springs I6 are applied to the side of the standard I5 which is remote from pivot I9, these springs being engaged at their upper ends with lugs 18 on the sides of standard I5 and at their lower ends with hooks fixed in the turntable 3|. The stressing of these springs during the lowering of the top of the ladder by tilting the standard I5 about pivot I9 serves to counter-balance the increasing effective leverage of the ladder as its angle to the vertical is increased, and thus the contractive effort of these springs in aiding the subsequent erection of standard I5 by means of the jack-screw and the rest of the elevating gear keeps the effort required to return the standard and ladder to elevated position practically constant regardless of the extent to which the ladder has been slanted.

By means of the train of mechanism just described, the operator is enabled to bring back the standard I5 from slanted to erect position withthe ladder clamped down in erected position thereagainst, in order to raise the free extremity of the ladder, and of course to let the standard tipover to lower the free end of the ladder, While standing fully erect and while applying his force to a hand crank that is located at or about the level'of his waist, where his weight and strength can be applied most effectively for this purpose. Additionally, through the mechanical advantage conferred by the powerful crank 15 and the reduction gearing at bevel gears 51, 69, added to the power already given him by jack-screw 2|, and aided by the counterbalance'springs 76, he is enabled to handle the ladder and to raise and lower it with facility even though it is in fully extended relation.

The provision of the universal joint arrangement avoids the diificulty otherwise met with in attempting to extend the jack-screw shaft upward to a level where the operator could apply his force to it Without needing to bend over, while still keeping it accessible for manipulation, such difliculty being the gyration of the free end of the jack-screw shaft toward and from the lower portion of the ladder as standard I is tipped and subsequently erected, which gyration would otherwise bring the upper end of the jackscrew shaft, or any hand wheel or crank applied thereto, into or through the plane of the ladder, to interfere with the rungs thereof, the climbing of the ladder, and the tipping of the ladder up or down about the axis i9 with corresponding rise and fall of the foot of the ladder. Omission of rungs to avoid such interference would make the climbing and descending of the ladder more diificult and risky. By the improved arrangement, the jack-screw can be slanted to provide clearance from the rungs throughout its entire amplitude of gyration, and its upper end need not itself be accessible because the driving means for the screw continue on above it, to a height and position where easily accessible to the operator.

The telescoping joint in the drive shaft for the jack-screw solves the problem of providing a support or mounting for the gears and crank at the most convenient point, namely on the tilting standard I5, in spite of the fact that such standard changes its position as the jack-screw is rotated.

To provide for releasing and re-engaging the ladder clips or hold-downs from the position where the operator stands in Working the elevating gear, these clips I! are hinged at I9 on lugs 8| fixed on inwardly extending flanges 83 of brackets 85 welded to the depending flanges of angle irons 81 forming the horizontal side members of ladder-rack 89 which extend forward over the cab 9| of the vehicle. The horizontal flanges of angle irons 81 are cut out as indicated at 93, just to the rear of the ladder-guides '95 on the ends of such angle irons, and just forward of ladder-stop 94, to provide for the outward movement of the shanks of clips 11 which removes the horizontal flanges at the top of the clips from over the ladder. Springs 91, bolted at 99 to the outside of brackets 85, bear against the shanks of the clips in an outward direction tending always to swing the clips oute wardly to free the ladder. An eye-bolt IIII is threaded through the shank of each clip I! just above the point of engagement of spring 91 therewith, and is secured by a lock-nut; to this eye-bolt is pivotally connected a yoke I03 to which is attached a flexible cable I 95 sliding through guide tubes I01 clamped at I09 and III to suitable frame-members of ladder-rack 89, and changing direction from an extent crosswise of the ladder-rack to one lengthwise thereof. At their rearward ends the flexible cables I05 are fixed to a member H3 connected by link H5 and yoke II! with an operating lever II9 pivoted at I 2| on a sector I23 welded to cross member I25 at the rear end of ladder-rack 89, the sector being provided with ratchet teeth I21 along its lower edge with which engages a spring pressed pawl (not shown) released by pressure on grip I 29 of operating lever H9.

With the operating lever H9 thus located within a couple of feet of the top of standard I5, an operator standing alongside standard I5 in position to turn crank i5 can easily reach up to press grip I29 and thus allow springs 9'! to pull operating lever H9 and cables Hi5 forward to effect the outward movement of ladder clips 1'! which frees the ladder from the ladder-rack. With very little change of position the operator can then pull down the foot of the ladder and secure it to standard l5, release foot-operated clamp ISI, rotate the ladder as desired on its turn-table, re-establish the clamped relation of the turn-table by clamp i3I, extend the upper section of the ladder and tip the standard I5 to bring the free end of the ladderto the desired spot in space by turning crank i5. After use, a reversal of these operations returns the ladder into carrying position between guides on the rack 89, whereupon a rearward pull on operating lever H9 restores the clips 17 to operative relation with the ladder to hold it tightly down in place on the rack. As is obvious, all of these operations are performed by the operator while standing within the vehicle, and Without occasion to descend to the ground.

While we have illustrated and described certain forms in which the invention may be embodied, we are aware that many modifications Y may be made therein by any person skilled in the art, without departing from the scope of the invention as expressed in the claims. Therefore, we do not wish to be limited to the particular forms shown, or to the details of construction thereof, but what we do claim is:

1. In a portable aerial ladder, in combination, a ladder, a turntable, a support for the ladder tilting on the turntable to tilt the ladder, control governing the movement of the top of the ladder in vertical and horizontal directions, located at the turntable and the support thereon, a ladder rack supporting a portion of the ladder that is remote from the support, a plurality of hold-down devices on the rack located at a point remote from the support, and remote control devices for releasing and re-engaging the holddown devices comprising a lever within reach of an operator standing at the first-named controls, and intermediate connections permitting disengagement of the hold-down devices from and causing re-engagement of the hold-down devices with the ladder by movement of the lever first in one direction and then in the other.

2. In a portable aerial ladder for vehicles, in combination, a ladder pivotally mounted to be mechanically raised and lowered under manual control from within the vehicle, a ladder rack, hold-down devices located at a point remote from the pivotal mounting holding the ladder down against the rack, means controlling the position of the hold-down devices, and a handlever within reach of an operator standing within the vehicle at the said controls for the raising and lowering, actuating the said means to cause release and re-engagement of the ladder by the hold-down devices, whereby the entire operation of releasing, erecting, lowering, and again securing the ladder for transportation can be efiected from a central position within the vehicle.

ALBERT J. KILEY. JOHN T. KILEY.

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