US1214774A - Aerial ladder for fire service. - Google Patents

Description

T. B. GRANT.

AERIAL LADDER F'OR FIRE SERVICE. APPLICATION FILED FEB. 2u. |916.

1 ,2 4,774 Patented Feb, 6, 1917.

a SHEETS-SHEET 1.

156mm;- AERIAL LADDER FOR FIRE SERVICE.

APPLICATION FILED FEB. 28, 196- 1 ,214374. 'A v Patented Feb. 6, 19W.

I 3 SHEETS-SHEET 2.

WITNESS NVENTOR A TTURNE Y T. B. GRANT. AERIALYLADDER FOR FlRE sER-v|cE.

APPLICATION FILED vFEB. 28, 1916. 1,214,774. Patented Feb. 6,1917.

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INVENTUR WITNESS` i am@ w )i IA.

W ATTORNEY TAYLOR B. GRANT, OF BROOKLYN, NEW YORK, AZSSIGNOR TO THE CITY OF NEW' YORK, A MUNICIPAL CORPORATION.

'Specification of Letters Patent.

PatentedlFeb. (il, 1917.

Application filed February 28, 1916. Serial No. 80,888'.

To @ZZ-whom t may concern.'

Be it known that I, TAYLOR B. GRANT, a citizen of the UnitedV` States, and a resident of the borough of Brooklyn, city of New York, county of Kings, and State of New York, have invented a new and useful. Improvement in Aerial Ladders for Fire Service, of which the following is a specification.

This invention is an improved type of aerial ladder for fire service, the object being to secure a substantial reduction in the collapsed'length of the ladder, thereby enabling it to be mounted on a ladder truck of comparatively shorter wheel base which can be maneuvered with greater ease and safety in narrow and crowded city streets; and in connection therewith to provide means for extending the ladder and locking it at any rung desired and for unlocking and lowering the ladder from any position.

A further object of the invention is the provision of means for taking up the shock of the descent of the aerial part of the ladder. V i

Other features and objects will become apparent to those skilled in the art as the speciiication proceeds and the novel features and combinations will be set forth more particularly in the appended claims.

In the accompanying drawings: Figure l is a view of the ladder collapsed andswung down to its carrying position, the truck being represented diagrammatically; Fig. 2 is a plan view of the ladder in this condition; Fig. 3 is a cross-section on an enlarged scale through the adjacent side beams of the ladder sections; F ig. l is an enlarged fragmentary illustration illustrating the safety stop or shock absorber; Fig.` 5 is a horizontal section on the line 5 5 of Fig. 4; F ig. G is a view similar to Fig. showing the first aerial section of theladder in the act of being released from the holding device associated with the safety stop; Fig. 7 is an enlarged fragmentary view illustrative of the stop provisions for causing the rst aerial section to take up the upward movement after the second aerial section has been raised relatively thereto, the cover plate of the casing for the releasable stop and its trigger device being broken away; Fig. S is a schematic view on a small scale representthe ladder as fully extended and showmore particularly the course of the raisand lowering cables; and Figs. 9 to l2 are sectional illustrations showing diiferent stages in the operations of raising and lowering the aerial sections.

Theaerial ladder in common use for fire service consists of two sections, a bed section and an aerial section, with automatic catches for locking the aerial section at any elevation. The bed section is pivoted at its base to the upper half of a turntable, the lower half being rigidly attached to the frame of a ladder truck. The side beams of the aerial sections rest between the beams and upon the rungs of the bed section. In using a ladder of this type, the bed section is first swung upward from a horizontal to a nearly vertical position, the aerial section is then extended by means vof a cable and windlass supported on the turntable, and the upper half ofthe turntable is then rotated on the lower half by means of an internal gear and pinion, thereby bringing therextended ladder to the desired positionagainst the building.

The ladder of the present invention is, or may be, similar in these respects to the known construction, but is composed of three or more sections, having two or more aerial sections instead of a single aerial section whereby the advantages of a shorter collapsed length are realized. This increase in the number of the sections involves certain features in connection with the raising and lowering and the locking and unlocking of the aerial sections which will be hereinafter described.

The body of the truck is diagrammatically represented at l, and 2 is the main pivot of the ladder, a showing of the turntable being omitted for the sake of simplicity. Any suitable or usual means may be provided for swinging the ladder from its recumbent to its erect position and for holding it in this latter position, such means being diagrammatically represented by the screw 8.

The bed section of the ladder, which is the one mounted on pivot 2 and acted upon by the device 3, is designated by the numeral Al, while 5 and 6 are the i'irst and second aerial sections, respectively. It will be understood, of course, that the invention may be carried forward by increasing the number of aerial sections if desired. The first aerial Section 5 slides on the rungs 7 of the bed section and is held in relation thereto by suitable guides 8 entering grooves in its side beams, the said guides being fastened to the side beams of the bed section. ln like manner the side beams of the second aerial section slide upon the 'rungs 9 of the first aerial section and are held in assembled relation by overhanging` guides 10 carried by the side beams of the first aerial section.

he aerial sections are extended and lowered by means of two drums 11 and 12 fastened on a shaft 13 operated by a handle lll. From the winding drum 11 a cable 62 passes over a slidable guide pulley 15 on the pivot 27 thence upward (see Fig. 8) to and over a pulley 16 on the. upper portion of the bed section, thence downward to and beneath a pulley 17 on the lower portion of the first aerial section, thence upward to and over a pulley 18 on the upper portion of the first aerial section, and thence downward to a lower rung of the second aerial section, to which it is fastened, as indicated at 19. From this point of fastening the same or another cable extends downward to and is w und upon the lowering drum 12. Adjacent the point 19 yielding` provisions may be introduced in-the line of draft, as repre.- sented diagrammatically by the springs 20. FV ith a raising and lowering mechanism of this character the aerial sections will be eX- tended and folded in succession; that is to say, if the parts are folded and the shaft 13 be revolved to wind the cable 62 upon the drum 15, the second aerial section 6 will be the lirst to be raised, and when this section has reached the limit of its upward movement relative to the first aerial section 5 then this first aerial section will take up the movement, and thereafter both of them will rise until the rst section has been raised as far as it will go relatively to the bed section.. ln lowering, the aerial sections lirst descend together in the positions which they assumey in the extended condition. When the first aerial section comes to rest against the shock absorbers 23, the second or upper aerial section is released and lowered upon the first aerial. section until its lower end cncounters stops 22 (see Fig. 2) fastened to this section. The second aerial section can be locked at any degree of extension rclatively to the first, and in like manner the first aerial section can be locked at any point of relation to the bed section by means of automatic catches These catches are. of known construction, each being springpressed so as to take over the successive rungs which it passes in its ascent and being provided with a guard adapted to close the hook, so that the ladder will slide idly over the rungs in the lowering operation, this guard being held by suitable spring means in either the open or the closed conditions illustrated in Figs. 9 and 12. Locking devices of this character are disclosed in prior patents, to which reference may be had for a fuller understanding of their construction and operation. lt will be sufficient to say that when one of the aerial sections is to be lowered, it is first moved upward a short distance, suflicient to cause the guards 25 of its catches to pass the rung upon which these catches 'rested` then upon lowering the section the guards press against this rung and are thereby swung upward to close the hooks, so that the latter cannot engage the rungs during the further downward movement.

in the raising operation, already stated, the second aerial section starts upward before the first, and the point at which the 'nrst section takes up the movement is determined by cooperative stops 26 and 27 carried by the sections, respectively. When the stop 26 meets the stop 27 the upward movement of the second aerial section relatively to the first ceases, and thereafter both sections rise together,

9 shows the second aerial section almost fully raised relatively to the first aerial section and the stop 26 about to contact with the stop 27, the catches 2st of this section being ready 'to snap over one of the rungs 9 of the intermediate section.

Fig. 10 shows a further stage in the raising operation, wherein the stop 26 is in contact with the stop 2 7, the catches 24C of the second aerial section are in a position to rest upon the rung of the first aerial section, whereon the second section will be supported as soon as the raising movement is arrested, and the lirst aerial section has just been started on its upward movement.

Fig. 11 illustrates a stage in the lowering operation wherein the first aerial section has been fully lowered and is resting upon the shock absorbers and the second aerial sec,- tion is in readiness to be lowered relatively to the first. Before this can be done, it is necessary, as already explained, to move the second aerial sect-ion upward for a short distance, in order to unlock it, but this cannot be done as long as the stops 26 and 27 remain opposite to each other. l, therefore, provide means whereby the stop 27, is retracted when the first aerial section is lowered. Such retracted position of the stop is shown in Fig. 11, permitting the second aerial section to be moved upward to the position shown in Fig. 12. From this position the second aerial section may be lowered until it rests upon the stops 22, the guards 25 of its catches being swung upward to close the hooks, as already described. lt will be noted in this view that an additional permanent stop 28 may be provided above the movable stop 27, to prevent excessive upward movement of the second aerial section.

The preferred construction of the movable stop 27 and the means for controlling the same are illustrated in Figi. 7. As there shown, the stop 27 is formed-on the end ofabar 29, which is slidably guided in a'h suitable casing or support fastened to the inner faces of the side rails of the second aerial section. A spring 3l acting upon the bar 29 tends constantly to retract the stop 27. The stop is projected intoy the path of the stop 26 by means of a trigger device 32, theV tailv of which cooperates with the top rung 9g' of the bed section. This trigger device is piv'oted at 33 andv is adapted to hold the stop 27 projectedy in the position of the trigger device shown in' Fig. 7 and throughout the range of move-ment of this device between such position, substantially atv right angles to the ladder, and the position in which it points toward the main pivot 2. This is accomplishedv by forming the forward portion of the trigger device with a quadrantal surface or edge 34, which is substantially concentric with the pivot 33. When the trigger device is moved from the position of Fig. 7, so that itsv tail points away from the mainpivot 2, the stop 27- is free to be retracted by the spring 3l, and when the trigger device is brought back to the position of Fig. 7 the stop is projected. These eiects are due to the cam surface 35. Springs 36 acting upon the trigger device tend to hold the latter in andv return it to the positionI of F ig'l 7, that is to say, a position in whichl the stop 27 is projected into the path of the stop 26.

In the' lowering or collapsing of the ladder, the extended aerial sections are lowered in unison until the lower of these sections is brought to `a cushioned stop uponv the shock absorbers. At this time the tail of the trigger device 32 is turned upward through contact with the .rung 9f. This brings the cam surface opposite the rear end of the bar 29 and permits the spring 3l to retract the movable stop 27, bringing the stop into the position of Fig. ll. The second or upper aerial section may now De raised for a. short distance, as shown' in Fig. l2, for the purpose of unlocking its automatic catches, the extent of this unlocking movement being limited by the fixed stop 28. The second aerial section may now be lowered until it comes to rest against the stops 22 of the first aerial section. The operator then grasps the aerial part of the i ladder and forces it downward an extrav distance, permitted by the springs 37 of the shock absorbers, and by virtue of this movement the tail of the trigger device 32 is carried below the top rung 9a of the bed section, thereby permitting this trigger de:

vice to be restored to the normal position of Fig'. 7 by the action of the springs 36. This restoration of the trigger device again projects the stop 27 into the path ofthe stop 26, so that when the ladder 1s a'gam to be' extended the operationv heretofore described will beA repeated. aerial portionof-the ladder against the tension of the springs 37, as described, the operator releases the'said portion, which then moves upward under the action of these springs until the tail of the trigger device 32 lies beneath the rung 9a. Vhen the ladder is extended again, the second aerial section moves upward relatively to the first, as described', and when the first aerial section takes up the movement the triggerdevice isr` foldedidownward beneath the rung 9, and in? so doing is turned approximately af quarter of a' revolution about its pivot 33 before it can escape above this rung and be restored to the normal position of Fig. 7. In so doing, however, its arcuate surface 34; isin contact with the rear end of the bar 29, and consequently the stop 27 remains in projecting position.

lllhile for convenience a. single stop 27- and trigger device 32 have been referred to in the foregoing description of operation, it will be understood that it is preferable to duplicate the arrangements of Figs. 9 to l2 at both sides of the ladder.

The shock absorbers or safety stops, as preferably constituted, comprise plungers 38 slidable in guides 39 and -tO of fixtures al fastened to the side rails of the bed section of the ladder. These plungers are acted upon in an upward direction by compression springs*` 37, which are coiled about the' portions of the plung'ers between the guides l() and collars 43v fast on the ,plungers The plungers are provided with grooves or recesses ist for engagement by the 'ends of locking pins 45. These pins or dogs are urgedV into locking position by springs 46 housed' in the guides 39 and may be withdrawn manually by means of handles 47. When the ladder isextendedy and the weight of the aerial sections consequently taken off the plunge'rs 38, the springs 37 hold these plungers in relatively elevated positions with the 'recesses lli substantially above the pins Connected with the locking pins iin are detent or holding devices 49, which cooperate with fingers 50 projecting downward from the lower ends of the side beams of the firstl aerial section. These locking del vices and the said fingers are formedv with appropriate camming surfaces 51'y and 52, whereby the vfirst aerial section when folded andswung downward to horizontal position is held with sufficient? security against accidental release or against the effect of the vibrations of the truck when in inoti'om-but whereby the said first aerial section may release itself when the ladder is extended. At such time, that is to say, when the stop 26 has brought up against the stop 27 sothat further draft upon the hoisting cable 12will cause the first aerial section to move up- Ha-ving depressed thel loo ward, the cam surfaces 52 on the fingers 50 will act upon the cam surfaces 51 on the holding devices A9, so as to force the latter outward, and in so doing the pins a5 are withdrawn from the notches le of the plungers of the shock absorbers. The purpose of locking the shock absorber plungers in the collapsed condition of the ladder is to keep the springs 87 from displacing the aerial portion of the ladder or causing vibration thereof. It will be evident thatif means were not provided for locking the shock absorbers, the latter would tend to expand when the collapsed ladder was swung down about the main pivot 2 to horizontal position, thus forcing the aerial portion of the ladder outward with reference to the bed section and permitting a certain amount of vibration as the truck rolls over the streets.

lVhile l have described one embodiment of my invention and its operation in detail, it will be understood that in practice many changes may be made and refinements introduced without departing from essentials. For example, the guides for the hoisting and lowering cables located on the sections of the ladders are conveniently represented as pulleys mounted directly on the rangs, but in practice it will be preferable to employ pulley blocks.

llVhat l claim as new is:

l. A sectional fire ladder, comprising abed section, first and second aerial sections, automatic catches for supporting said aerial sections when elevated, said catches being releasable upon slight upward movement of the section supported thereby, coperative stops on the aerial sections to arrest the upward movement of the second relative to the first, one of said stops being movable, to permit said upward movement for releasing the catches of the second aerial section, and means for withdrawing the movable stop.

2. A sectional lire ladder, comprising a bed section, first and second aerial sections, automatic catches for supporting said aerial sections when elevated, said catches being releasable upon slight upward movement of the section supported thereby, a device for arresting the upward movement of the second aerial section relative to the first in order to compel the first to rise, and means for automatically rendering said device ineffective on lowering of the aerial sections, so that the second aerial section may be moved upward an extra distance to release its catches.

3. A sectional fire ladder, comprising a bed section, first and second aerial sections, automatic catches for supporting said aerial sections when elevated, said catches being releasable upon slight upward movement of' the section supported thereby, a movable stop on the upper part of the first aerial section coperative with a portion of the second section to arrest the relative upward movement of the latter, and means coperative with the bed section for controlling said movable stop.

a. A sectional fire ladder, comprising abed section, first and second aerial sections, automatic catches for supporting said aerial sections when elevated, said catches being releasable upon slight upward movement of the section supported thereby, a movable stop on the upper part of the first aerial section coperative with a portion of the second section to arrest the relative upward movement of the latter', and a pivoted trigger device mounted in connection with said movable stop for controlling the same by cooperation with the bed section.

5. A sectional fire ladder, comprising a bed section, first and second aerial sections, automatic catches for supporting said aerial sections when elevated, said catches being releasable upon slight upward movement of the section supported thereby, a movable stop on the upper part of the first aerial section coperative with a portion of the second section to arrest the relative upward movement of the latter, a spring tending to retract said stop, a cam member for projecting the same, spring means for urging said cam to project the stop, and a trigger connected with the cam and coperative with the bed section.

6. A sectional lire ladder, comprising a bed section, first and second aerial sections, automatic catches for supporting said aerial sections when elevated, said catches being releasable upon slight upward movement of the section supported thereby, a movable stop on the upper part of the first aerial section cooperative with a portion of the second section to arrest the relative upward movement of the latter, a spring tending to retract said stop, a cam member for projecting the same, spring means for urging said cam to project the stop, and a trigger connected with the cam and coperative with the bed section, said cam having an approximately quadrantal surface whereby to hold the stop in projected condition when the trigger latches by the bed section at the beginning of the raising operation.

7. A sectional fire ladder, comprising a bed section, first and second aerial sections, automatic catches for supporting said aerial sections when elevated, said catches being releasable upon slight upward movement of the section supported thereby, a movable stop on the upper part of the first aerial section coperative with a portion of the second section to arrest the relative upward movement of the latter, a trigger device mounted in connection with said movable stop whereby said stop is retracted when la said trigger device contacts with the bed section on the lowering movement, and a shock absorber for the first aerial section permitting an eXtra depression of said section to release said trigger device in order to restore the movable stop.

8. ln a re ladder, comprising a bed section and an aerial section, a shock absorber for cushioning the descent of the aerial section, the said shock absorber comprising a mounting on the bed section of the ladder, a plunger slidable therein, a spring acting ipon the plunger, and means for locking said plunger'.

9. In a fire ladder, the combination with an aerial section, of a shock absorber for cushioning the descent thereof comprising a. spring and a plunger, a yielding device for holding the aerial section in lowered or collapsed position, and an automatic lock for the plunger having means whereby it is released by upward movement of said aerial section.

l0. In a fire ladder', the combination With an aerial section, of ashock absorber for cushioning the descent thereof comprising a spring and a plunger, a spring-pressed dog to enter a recess in the plunger, a linger on the aerial section, and a holding device cooperative With said inger and connected with said locking pin, said detent and finger being formed with engaging portions whereby the finger may release itself and force the locking pin out of locking engage ment When the aerial section is raised.

Dated February 24th, 1916.

TAYLOR B. GRANT. Witnesses:

GRACE H. EMPEN, TEKLA A. ANDERSON.

Copies of this patent may be obtained for five cents each, by addressing the Commissioner of Patents, Washington, D. C.

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