US2569890A - Safe load indicator - Google Patents

Description

Oct. 2, 1951 R. HICKS SAFE LOAD INDICATOR Filed May 21, 1947 7 2 dad/ 35 95% INVENTOR BY q ORNEYS Patented Oct. 2, 1951 UNITED STATES PATENT OFFICE 2,569,890 SAFE LOAD INDICATOR Reginald Hicks, Yonkers, N. Y., assignor to American-La France-Foamite Corporation, Elmira, N. Y., a corporation of New York Application May 21, 1947, Serial No. 749,608

12 Claims.

In order to safeguard the lives of firemen and other users of aerial ladders, such as are mounted on fire department trucks, it has been proposed to provide an automatic, safe-load indicator adapted to respond to the maneuvering of the ladder and to enable the operator to tell, by a glance at a scale, the maximum load which can safely be applied to the ladder at any extension and elevation.

As with all apparatus which is apt to be put to use under emergency conditions, it is of the utmost importance that the indicator mechanism be of a character to operate reliably and with a minimum of attention and maintenance; and it is the primary object of this invention to supply.

that need and in a mechanism so organizedthat it can be readily applied to turntable ladders in the limited space usually available.

Other objects and advantages of the invention will be apparent from the following description and accompanying drawings of the preferred One of such means is shown as consisting of a shaft I adapted, as below described, to move axially in one direction or the other as ladder 2 (of which the lower end portion only of one of the side rails is illustrated) is extended or reshown) to extend or retract the ladder. To the end of shaft l is secured a cable I2, which is one of two cables by which the indicator mecha-: nism is actuated. l

The other actuating cable, I3, is secured to, post 3 and the arcuate movement of the post as the ladder is raised and lowered about the axis of shaft 4 is applied to operate this cable by training the latter over a pulley I4 carried by an arm l5 mounted to swing about a different axis from that about which the ladder pivots. Arm I5, the forked end of which straddles post 3, is pivotally mounted on the end of a fixed bracket arm I6 and the cable I3, as indicated, is passed a1ong the pivot axis of arm l=5 and over other appropriate guide pulleys I'I. As the ladder is raised and lowered about its pivot axis, the post 3 approaches and recedes from the pivot axis of arm I5, so that the endof cable I3 attached to the post is moved toward and from pulley I4. Cable I3 thus responds to the raising and lowering of the laddenjust as cable I2 V responds to its extension and retraction, and

tracted. The other of such means is shown as consisting of a post 3 projecting laterally from the ladder so as to be swung in an are as the ladder is raised and lowered about the axis of shaft II, which latter is schematically illustrated as comprising the shaft which carries the ladder extension cable and drum, generally designated 5.

The axial movement of shaft I is effected by the engagement of an externally threaded portion 6 of the shaft with an internally threaded shaft I adapted to be rotated by pinion 8 from gear 9 mounted on cable drum shaft 4. Shaft I is held against rotation, as by the engagement with a slot in the shaft of a key carried by a collar In which is supported by fixed bracket I I. Thus, as above stated, shaft I is moved axially, in one direction orthe other, as the cable drum shaft in response to ladder movement. stance the cable I2 is shown wrapped around and fastened to a collar or small pulley 22 secured to each independently of the other.

The indicator, Which may consist of any api propriately calibrated device movable to show the varying safe load limits as the ladder is operated, is shown as consisting of a series of three f drums I8, I9, 20 the peripheries of which carry the load limit indications which may be ob-,

served, as through windows in a suitable cover panel (not shown). Drum I8 may serve to indicate the safe load limits when the ladder is in use with its upper end supported, as against a building, drum l9 when the ladder is in use as a water tower, and drum 20, when the ladder is in use with its upper end unsupported, but not as a water tower. Appropriatel calibrated, all three drums may be secured to a single indicator shaft 2!.

One of the indicator actuating cables is coupled to the indicator shaft so as to rotate it In this inshaft 2 I.

suspended from the pulley is a yoke 25 to which cable I3 is fastened. Fixed guidepulleys are in medicated at 26; and a single spring'ZI, having a is rotated by the usual drive mechanism (not cable connection 28 to indicator shaft pulley 29, serves to bias the shaft in a direction opposite to the pull of cable I2, so as to tension the latter. The spring also serves to sustain the floating pulley and maintain cable l3 under tension.

It will be apparent that, as the result of this arrangement, the extension and retraction of the ladder is applied directly to rotate the indicator shaft through the medium of cable I2; that the shaft is also rotated by the rising and falling of floating pulley 23 as the ladder is raised and lowered about its pivot axis (each of these .operations being free to take place independently of the other) and that the cables :ere, alsorfree -te operate conjointly or differentially :to register simultaneous adjustment of the ladder, bothas to raising and as to extension. I

In the perspective drawing the components the said pulley and to move the indicator in the reverse direction to that effected by tension of the said cable.

4. In a safe load indicator for an aerial ladder, the combination of two independently movable means connected to the ladder, said means being independently movable, respectively, in response to the-raising and lowering and .to the extension and retraction of the ladder, a rotatable indicator shaft, an indicator carried by said shaft, a :single continuous cable having one end connected totheindicator shaft and its other end connected have been spread out for clearness of illustration In .the light 0f. theforegoing description, the

following is -.claimed-:

a safe-load indicator :for an aerialladder having two ,means independently movable, respectively, inresponsetothe raising and lowering and to the extension and retraction ofthe ladder, and an,.-indicator shaft: the ,combinationof a cable wrappedaronnd the Shaft and having .a remote endconnectedto one ,of said means,,.an, intermediate-stretch of the cable including a depending-loop, :a ,pulleyseatedin said loop, a ,second cable havin g one end connected .to the pulley and itsotherend connected to the other ,of said means, and a spring coupled to the indieatorshagft and biasedctorotatethe, same in a direction to keep both of the said cables taut.

2;;In1a safe load indicator for an aerial ladder having tworneans independentlymovable, respectivelminresponse to the raising and lowering .andv

pled to T'theindicatorshaf t and biased to counter-- balance the said pulley and to rotate the indicator shaflLin ,thereyerseldirection to that effected .by tensionof the said cable.

3,..,In ,a,safe load indicator. for an aerial ladder havingtwomeans.independentlymovable, respectively,.;inl response to the raising and lowering and to the extension and retraction of the ladder, and a movable indicator: the combination of a cable coupled-to the indicator and having one of; its ends connected to one .-of said movable:

meanaand a floating pulley having "connection torand ,bodily movable by the other .of said mo ahle'i-means, the said pulley en in a loonofthe cable fintermediatezthe .said endzathereof =;and the to one of said movable means, an intermediate stretch. Qfqsald cable including a depending loop, appulleyiseatedjn said loop a second cable havingoneendconnected to said pulley and its other ,end connected to the other of said movable means,

and a, spring coupled to the indicator shaft and -lbiasedrto counterbalance the said pulley and to rotate the indicator shaft in a direction opposite tdthe nullof the first-mentioned cab e, 7

r5. i-Aasafe loa indicator for an aer alladdel" inclndingtwo independently .movablemeansasw 1 sociated with the ladder, said means beinginependently m va le, resp ively, .inr sp nseto the rai ing and loweri f the ladder and to, the extensionand re rac ion o h ladd r, arc-'- tatableindicator shaft, and. indicator, drum carried by said shaft, a calibrated scalenssnciated :with said ind cator .drum, said scale indica ing by direct r a in th ma mumsai oadfor th ladder, acable having oneend thereof wrapped around theindicator shaft and the other end thereof connected to and movablein resncnseto movementofcnc of th t independentlylniov-r able means, a h at n pull y en a in with "said cable. intermediate. its ends, a second c ble .QQhnecting the pulley totheiothereof saidindcp ndently movable, means, said se on lcable be- 7 indicatin b .direct readi the max mum safe indie tcnand a .sprinabiased; to icounterbalanceiiflfi means, said second .cable being movable in ,re--.'

sDQnse to movementof the lastementioned movable nieans, and a counter-balance connected. .to the indicator shaft, said cou-rrterebalance. urging the indicaton shaft in-a direction to keep ,both

ofisaidcablestaut. V V

7 -1En -a ,-.s.afe load indicator for :an aerial ladder of-the t pe that is sup o te at ne-end one base. with: the other end bein f e for eleva ion nd extension to different p si ons the combination f anra ll rm v bl member c nn cte t uth ;11adder,.,said m mber bein movab Vai :resnons 'itozthe :eatan on and-,retracticnn rtbe ladder, an angularly movable member carried by the ladder, said angularly movable member being movable in response to the raising and lowering of the ladder, a movable indicator, a cable having one end connected to said indicator and its other end connected to one of the movable members, a pulley engaging said cable intermediate its ends and a second cable having one end connected to said pulley and its other end connected to the other of said movable members.

8. In a safe load indicator for an aerial ladder of the type that is supported at one end on a base with the other end being free for elevation and extension to different positions, the combination of an axially movable member connected to the ladder, said member being movable in response to the extension and retraction of the ladder, an angularly movable member carried by the ladder, said member being pivotally movable about the fixed end of the ladder in response to the raising and lowering of the ladder, a rotatable indicator shaft, an indicator carried by said shaft, a calibrated scale associated with said indicator, said scale being calibrated to indicate by direct reading the maximum safe load for the free end of the ladder at different elevations and extensions of the ladder, a single continuous cable having one end wrapped around said indicator shaft and its other end secured to one of the movable members, a pulley engaging with said cable intermediate its ends, and a second cable having one end connected to said pulley and'its other end conected to the other of said members.

9. In a safe load indicator for an aerial ladder of the type that is supported at one end on a base with the other end being free for elevation and extension to different positions, the combination of an axially movable member connected to the ladder, said member being movable in response to the extension and retraction of the ladder, an angularly movable member carried by the ladder, said member being pivotally movable about the fixed end of the ladder in response to the raising and lowering of the ladder, a rotatable indicator shaft, an indicator carried by said shaft, a calibrated scale associated with said indicator, said scale being calibrated to indicate by direct reading the maximum safe load for the free end of the ladder at different elevations and extensions of the ladder, a single continuous cable having one end wrapped around said indicator shaft and its other end secured to one of the movable members, a pulley engaging with said cable intermediate its ends, a second cable having one end connected to said pulley and its other end connected to the other of said movable members, and a spring coupled to said indicator shaft, said spring being biased to rotate the indicator shaft in a direction opposite to the pull of the cables.

10. In a safe load indicator for an aerial ladder of the type that is supported at one end on a base with the other end being free for elevation and extension to different positions, the combination of an axially movable member connected to the ladder, said member being movable in response to the extension and retraction of the ladder, an angularly movable member carried by the ladder, said member being Divotally movable about the fixed end of the ladder in response to the raising and lowering of the ladder, a rotatable indicator shaft, a plurality of indicator drums carried by said shaft, each of said drums having a different calibrated scale associated therewith with each of the respective scales indicating the maximum safe load for the free end of the ladder under a different load condition, a single continuous cable having one end wrapped around said indicator shaft and its other end secured to one of the movable members, a pulley engaging with said cable intermediate its ends, and a. second cable having one end connected to said pulley and its other end connected to the other of said members.

11. In a safe load indicator for an aerial ladder having two means independently movable, respectively, in response to the raising and lowering and to the extension and retraction of the ladder, the combination of a rotatable indicator shaft, a cable coupled to the indicator shaft for rotating the same in one direction and having one of its ends connected to one of the independently movable means, a floating pulley connected to and bodily movable by the other of said independently movable means, said pulley engaging a loop in the cable intermediate the said end thereof and the indicator shaft, counter-bah ancing means connected to the indicator shaft, said counter-balancing means tending to rotate the indicator shaft in a direction opposite to the rotation thereof by the cable and indicating means connected to and movable by rotation of the indicator shaft in either direction, said indicating means including a calibrated scale, said scale being calibrated to indicate the maximum safe load for the ladder.

12. In a safe load indicator for an aerial ladder having two means independently movable, respectively, in response to the raising and lowering and to the extension and retraction of the ladder, the combination of a rotatable indicator shaft, a cable coupled to the indicator shaft for rotating the same in one direction and having one of its ends connected to one of the independently movable means, a floating pulley connected to and bodily movable by the other of said independently movable means, said pulley engaging a loop in the cable intermediate the said end thereof and the indicator shaft, counterbalancing means connected to the indicator shaft, said counter-balancing means tending to rotate the indicator shaft in a direction opposite to the rotation thereof by the cable and indicating means connected to and movable by rotation of the indicator shaft in either direction, said indicating means including a plurality of calibrated scales, each of said scales being calibrated to indicate by direct reading the maximum safe load for the ladder under a different load condition.

REGINALD HICKS.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 1,456,061 Jowett et a1. May 2 2, 1923 2,015,957 Neal et al Oct. 1, 1935 FOREIGN PATENTS Number Country Date 291,556 Italy Dec. 19, 1931 595,554 France July 20, 1925

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