US2529193A

US2529193A - Safety boom stop

Info

Publication number: US2529193A
Application number: US637237A
Authority: US
Inventors: Earle F Rueter
Original assignee: Unit Crane & Shovel Corp
Current assignee: Unit Crane & Shovel Corp
Priority date: 1945-12-26
Filing date: 1945-12-26
Publication date: 1950-11-07
Anticipated expiration: 1967-11-07

Description

. R m g 9 u N U R w SM n 5 y 2, m WE T mm ,5 r 5 R m WM \w ms 65 EM u w R B E. M S mw mm k vfi sq kw 0 Nov. 7, 1950 Filed Dec. 26, 1945 Nov. 7, 1950 F. RUETER SAFETY BOOM STOP Filed Dec. 26, 1945 2 Sheets-Sheet 2 1 FIG. 6 FIG. 7

O/iF HO/ST BOOM HO/ST CONTROL INVEN TOR EARLE ERUETER ORNEY The presentinventionirelates ..to .stop appara- -tus and. more particularly toisafety boom stops for rotary cranes. and the like. "a -In the. operation-pf. a. mobile rotary crane it "is "necessary for safetyreasons to avoid raising 5 ,the pivoted hoist. bonibeyfond a predetermined height; 2 Boomi-stops for this: purpose have heretofore been devised, but these. have.:been open :to- Various objections .such as complexity of con- ;struction and relativelvhigh'costof manufacturefl .51 "K Anobject.ofTtheinvention isto'provide an improved safety boom s'top-which is of simple and (inexpensive construction arid-readily applicable .-.to. existing -m'a"C'hin6SiZ1 I r 'Anotherobject is to "provide a boomistop which is creliable in operation andwhich will not interfer'e with lthe' lowering f 1 the boomfrom' its =stop'ped'zposition. A "further.'object is to" provide fa boom stop which is particularlysuitably'for a loadhandling rmachinei'powereif-iby" an internal combustion 'senginei' 4- 'T The inven ion 'further consi's'ts inthe several features hereinafter-described and claimed. In the accompanying drawings, illustrating ecertainiiembodimentsi of the. invention," V

Fig. 1 is a schematic elevational view of a -safety1boom=stopfarrariged in accordance with the invention;- la't switchiwasing thereof being shown in 'se'ction'f J 'Fig.v 2is a fragmentary elevational view of the -switch'actuatingmechanism as it appears when -displacedby' the Braised boom, parts beingshown :in section;.:-. a Fig.1 3 istattran'sverse sectionalelevational View :taken generally-alongqthe line 3c3of Fig'. 1;

45..Figz .4iisjaschematic iwiiring' ;.diagram of the .stop'yas applied It'OLWgCI'EIlBDhflVlllg anzengine with battery. ignition; I Fig. 5 is a schematic wiring diagram of the stop as applied to a crane having an engine with magneto ignition; Y I

Fig. 6 is an elevational View of a modified form stop switch device, parts being shown in section; 1- Fig. 7 is a sectional elevational view taken generally alongthe line 11 of Fig. 6;

Fig. 8 is a schematic wiring diagram of amodi- .fied form of circuit for the boom stop, and

9 is. a side elevation of .a rotary, crane equipped with a boom stop of the invention, parts beingshown schematically. 1 1

V Referring to Figs.,1 toeand '9, the numeral F es n teszse er y a m bile a y 30 "on'the A-frame, as usual.

PATENT: OFFICE i i L iv -Earle-F.;Rueter, Milwaukea wis a'ssignor to Unitv Crane & Shovel Corp" West Allis, Wis., a cor ai enefllel w 1 1 1 Application December 26,1 945,"Serial No;631,237

5 Claims. (Cl.212-s9) crane of anyusual/construction. The machine includes a propelling undercarriage ll, here shown t'olbe of the crawler type, although'a wheel-type undercarriage may be used, as is well understood in this art. A rotating frame or turntable I 2 is rotatably mounted on the undercarriage and carries the usual mechanism for operating the machine," this mechanism inroluding a gear-case l3 and an engine or motor One suitable-type of undercarriage "and soperatingrhechah'ism'is shown inUnited States Patent 2,318,286,- to-Harold E. Brey and Hilbert E; Swan'songfor' Traction BrakeQissued' May-'4, 1943. The engine I4 is connected to the gear- 1c'as'e byairictionclutch' I5, Fig.1, controlled byiithet'usual actuatinglinkage I5. The gearcase' includes-the usual'bodm-hoisting drum' -l' 'l andiload-hoistingdrum- 18, the drum I! being -"rotated in any wellknovvnmanner as by a suitably controlled worm drive 19, Fig. 1. The turn- "tabIe carriesthe usual A-"frame 20, Fig. 9, and 'also.asuitable cab 2| having a front wall 22 and side wall 23,'Fig. 1'.' v iii A hoist boom'24 is "pivotally connected at' 2'5 topro'jecting supporting parts 26 atthe front of the turntable to swing in a vertical plane, and is adjustably elevated by a hoisting cable '21 which is wound on the drum I! and passes over sheaves 28'onthe boom point and sheaves 29 A load-hoisting cable 30 is-Wound on the jdrum' l8 and passes "over sheaves 3| on' the boom point and over a sheave 32' at a suspended load-engaging hook 33, as usual. t

5 In accordance with usual practice, the hoisting machine may be readily converted to various other forms;'such' as a clam shell, dragline, .iba'ck diggerfla nd excavatingshovel, by providingsu'it'able booms and "other equipment. A

finachine of this t'ype converted to an excavating '45 means are provided" for limiting the raising of the pivoted boom' 24'."byo-nd'.a predetermined height. The" stopmeanst comprises a control device designated generally by the numeral 34 and adapted to :cooperate'with the boom, as hereinafter' described. The control device 34'includes a casing 35 adapted to be rigidly mounted on ,th'ei-crane' cab-and-flhavin'g' front and rear Walls with aligned b'.ores;36 in which is'slidably mount- :ed;.a horizontal :iorwardly projecting ."rod 31 withv anabutmentxglisk 38.;at/its exposed front boom at a suitable distance above the pivot' 2 5 and carries a bolt 45 which is clamped in longitudinally adjusted position by nuts 46. A roller 41 is carried on the free end of the bolt and is adapted to abut against the end disk 38 of the stop rod 31 to force this rod rearwardly when the boom is raised to its safe maximum height.

Electric switches

48 and 49 are rigidly secured in the casing and are respectively disposed below and above the rod 31, each switch being mounted on a spacer block 58*, Fig; 3. 'These switches in- .clude respective pivoted plunger-actuatingroller arms 5| and 52, the rollers 53 of which bear on diametrically opposite sides of the collar 49, the latter having a cylindricalsurface 54 and a c'onical cam surface 55. The two switches, or at least the free ends of the roller'arms thereof, are longitudinally offset so that the switch 48 will operate slightly in advance of the switch '49'when the cam collar is returned to the'normal position of Fig. 1 by the spring 42. The 'switches per se are of well known construction andpreferably of a snap-action type. urged to open positionandrequires the application of pressure to its roller arm to 'hold it'in -closed position. The switch 49 is of the maintained-contact or. looking type and includes a reset button 55 by which the switch can be man- The switch 48 is springuallyactuated to closed position, the application of pressure to'the'roller arm 52 snapping the &0 switch to its open position. In-theposition'bf the parts shown in-Figs. 1 and 4 'the'switch 48 is held closed and the switch 49 is open. The

switches

48 and 49 are preferably of the double- -throw type, permitting each to be used either as a normally open switch or-anormally closed :switch, the switch 48 having selectively us'able contacts 48a and 48b-and the switch 49 having selectively usable contacts 49aand 4%.

In the present instance, the

switches

48 and 49 are connected in-theignition circuit of the crane engine, the switch 48 being a boom-actuated'limit switch for stopping :the engine when the boom is raised to its highest safe position. .In Figs. 1 and 4, the ignition circuit is shown to be of the battery type'and includes a battery 51,

manual ignition switch-58g-breaker '59-;with

shunting condenser 60, highetension' coil 8 I with .primary and secondarywindings anddistributor 82 connected to the engine: spark plugs'63; all

as usual. The limit switch- 48- is connected'in :series with the manual ignition switch. 58,,the

connection being made to theswitch' contact 48a,

Fig. 4. The manually operable switch 49 is connected in shunt to the switch 48, the connection being'made to the'switchcontact 49a. position of the parts shownin Figs.- 1 and 4,, the

In the limit switch 48' is held'in closed'position by the cylindrical surface 54 of the cam collar. 'so' as to completethe ignition circuit and permit operation of the engine. I a

In the operation of the'system of Figs. I and 4,

the raising of the boom to its highest' sa'fe position will push the spring-pressedrod ill-inwardly to the position of ;'2,-l permitting the limit switch 48 to snap to its open position, thus opening the engine ignition circuit and stopping the engine. This serves as a signal to the operator who then disconnects the driving connection to the boom-hoisting drum [1 and releases the engine clutch- I5. The operator then momentarily depresses the reset button 56 of the switch 49 shown.

which locks in closed position andreestablishes the ignition circuit through the switch contact 49a, thus permitting restarting of the engine.

: After the engine is again in operation the boom is lowered by manipulating the usual controls,

permitting the advance of the spring-pressed stop" rod 31 to its normal position. During this advance, the'limit switch 48 is restored to its closed position bythe cam surface acting on the switch arm 5|, and shortly thereafter the switch 49 is restored to its open position by the 'ca'm'sur'face 55 actingon the switch arm 52, thus placing the control device in condition for a subsequentbo'omstopping"operation. 1 "Occasionally, the" boom may be lifted .to "its highest safe position rby contact with a tree branch or other-obstructionwhile :the crane is travelling. However, thecontrol device will Ifunction'as'ab'ov'e desc'ribedto 'stopfthe engine,

thus immediately stopping the crane and. preventing damage.

"In' the modified form of the invention shown in "Fig.-- 5, the crane engine I 4 is provided with a high-tension ignition magneto 8|. This form of magneto is usually 'srendered' ineffective by 'short circuiting orIgrounding-the primary winding, as by a'manual-tswitclr58'. In applying the control device to this formeof"magneto circuit,

the switches 48 and 49rare connected in; series by way ofthe contacts- 48b and 49b to form-1a shunt around the manual. swit'clr 158'; l' the limit switch 48 being normally open butz-movable' to :cl'osed position'upon' the retraction'of-the stop rod' 31 by the -boom, and"the re'set switch 149 be- :ingnormally closed but mov'abie to openposition by the reset button 56 so as to permit restarting *ofthe engine. ':Since the: controlswitches 48 and 49 arer of, the double-throwf type, the -same switchesfcanbe used forthe 'circuits ofFigs. 4 and 5 with suitable changes in the wiring',---as J In the: operation of the-=stopmeans when arranged as irr Figi: 5,-; the r aising of the-boomto the limit position closes the switch48g thuszshortcircuiting the magneto -;;primary winding and stopping the engineq :By: pressing the reset button 56 of the switch -:4 9 v theifiagheto :primarypi'rcuit is reopened, thus permitting restartingfiof *the engine; A slightloweringzofzthe boom then reopens" the limit switch 48".andrecioses'the switch "49, thereby placing' the 'dontrol' 'device' incendi- *tion for; a subsequent boom stoppingioperation.

In the modified form o'frcoiitrbl crevicersnown 42, as inthe device of Fig. 1 The roller si ar-1d- 52"of'theswitehesi ooperate with ii horizontal surfac'e 54 a? l suitable mannen-a's Dy 54 .sec11red 'in the easin slidable in a and operations-ofthedevice of Figs. 6 and 7 is gtherwise the same as that of Fig. l.

In the modified form of the invention shown ln liig. '8,.the reset switch 49 is connected in series with an interlock switch 66 which is opened by a .'.b'0om hoist control lever B! when the latter hoisting position, thus preventing restarting? of, the engine until this control lever is moved outlof hoisting position. The limit switch 48 is fionil'ec ted in a control circuit including the sfv vitjch'contact 48a, a battery 68, and the winding fifljof arelay switch 10, the circuit also includinjg manual switch H. The relay switch controls'l "a suitable engine-enabling circuit here shown to include the battery 68, the relay switch contacts, a winding 12 ofan enginestop 13, and the manual control switch H. U By way of eX-- ample, the engine-enabling circuit may be an ignition circuit similar to that of Fig. 4 or Fig. 5. ln the case of a compression-ignition engine, the circuit may control the engine emergency stop, one known type of which functions by shutting off the air supply. The stop is also applicable to control a crane of the electric motordriven type.

The system ofv Fig. 8 further includes an alarm circuit having therein one or more alarm devices, such as a bell M and a lamp 15, these alarm devices being supplied with current by the battery 68 and the alarm circuit being established through the contact 481) of the limit switch 48. In the operation of the system of Fig. 8, the raising of the boom to its highest saie position actuates the limit switch 48', opening the control circuit through the relay winding 69 and closing the alarm circuit. The relay switch thereupon opens the engine stop circuit including the winding 12, causing stopping of the engine or motor. After shifting the boom hoist control lever 61 out of hoisting position, the operator depresses the reset button 56 of the switch 49 to effect closing of this switch, thereby reestablishing the relay control circuit through the then closed series-connected switches 49 and 66. The relay switch Ill then closes, permitting restarting of the engine. Since the boom hoist control lever is then out of hoisting position, there is no danger of continued raising of the boom. As the boom is lowered the limit switch 48 is returned to normal position, thus opening the alarm circuit and establishing a path for the current flowing through the relay switch windin 69. Shortly thereafter the reset switch 49 opens, placing the device in condition for a subsequentboomstopping operation.

What I claim as new and desire to secure by Letters Patent is:

1. In a load-handling machine having a hoist boom and power means for operating said boom including control circuit means and a boomhoist control member movable into and out of boom-hoisting position, a limit switch connected to said circuit means and having a power-enabling position and a power-disabling position, said limit switch bein normally in power-enabling position, mechanical means controlled by the boom for operating said limit switch to powerdisabling position upon the raising of the boom to a predetermined height and for restoring said limit switch to power-enabling position upon the lowering of the boom from its limit position, a manually operable locking-type reset switch connected with said circuit means and having an inactive position and a power-enabling position, said reset switch being normally in inactive position and being manually operated to power-enabling position when said limit switch is in power-disabling position, mechancal means controlled" by the boom for restoring said manuallyoperable reset switch from its power-enabling position to its inactive position upon the lowering of the boom from its limit position, and a third switch connected in circuit with said manually operable reset switch and having a mechanical actuatin connection with said boomhgistcontrol member for rendering said reset switch ineifective to energize the power means while said control member is in boom-hoisting position.

I2.' In a-safety stop device for a movable power operated member of a machine having power means for operating said member and electric circuit means for controlling said power means, ar eciprocable member movable between a normal position and a stopping position, yieldable means for normally urging said reciprocable member toward normal position, said reciprocable member adapted to be mechanically moved in the opposite direction to stopping position by the movable. member at an end of the travel of said movable'member, a limit switch adapted for connection with said circuit means and having a powerenabling position and a power-disabling position, said limit switchbeing normally in power-enabling position, mechanical means controlled by saidreciprocable member for operating said limit switch to power-disabling position upon the travel of said reciprocable member in stopping direction; a manually operable locking-type reset switch adapted for connection with said circuit means and having an inactive position and apower-enabling position; said reset switch beingfnormally in inactive position and being manually operable to power-enabling position when said limit switch is in power-disabling position, and mechanical means controlled by said reciprocable member for restoring said reset switch to its normal inactive position upon the return travel of said reciprocable member to its normal position.

3. In a safety stop device for a movable member of a machine having power means for operating said member and electric circuit means for controlling said power means, a limit switch adapted for connection with said circuit means and having a power-enabling position and a power-disabling position, said limit switch being normally in power-enabling position, mechanical means controlled by said movable member for operating said limit switch to power-disabling position upon the movement of said movable member to a limit position and for restoring said limit switch to power-enabling position upon the movement of said movable member from its limit position, a manually operable locking-type reset switch adapted for connection with said circuit means and having an inactive position and a power-enabling position and being manually operable to power-enabling position when said limit switch is in power-disabling position, and mechanical means controlled by said movable member in its movement from limit position for restoring said reset switch from its power-enabling position to its inactive position.

4. In a safety stop device for a movable poweroperated member of a machine having power means for operating said member and electric circuit means for controlling said power means, a reciprocable cam member movable between a normal position and a stopping position, yieldcam member toward normal position, said cam member adapted to be mechanically actuated'by' said movable member for moving said reciproca-r ble member in the opposite direction to stopping position at an end of the travel of said movable member, a limit switch adapted for connection with said circuit means and having a power-enabling position and a power-disabling position, said limit switch being normally in power-enabling position, mechanical means controlled by said cam member for operating said limit switch to power-disabling position upon the travel of said cam member in stopping direction, a 'manually operable locking-type reset, switch ted iorconnectionwvith saidcircuit means qndhaving an inactive position and a powerenabling position, said reset switch being normally in inactive position and being manually operated to power-enabling position when said limit is in powerdisabling position, and meal means controlled by said cam member iestoring said reset switch to its normal inactiveposition upon the return travel of said cem member to its normal position.

7 Inasafety stop device for a movable poweroperated member of a machine having power for operating said member and electric c rcuit, means for controlling said power means, a' casing, a rod reciprocably mounted in said casing and having a cam, said rod being longitudinally-movable between a normal position and a stepping position, yieldable means in said casing figrnormallyurging said rod toward normal po- Sit/1013 53151 rod projecting from said casing and adapted to be longitudinally displaced in the opposite direction to stopping position by said mov 8 able memberwhen, said movable member approaches an end of its travel, a limit switchirr said casing adapted for connection with said,

circuit means and having a powerrenabling'po sition and a power-disabling position, said limit switch being normally in power-enabling position, mechanical means controlled by said cam. for operating saidlimit switch to power-disabling position when said rod is moved from its normal" position to its stopping position, and a manually operable locking type reset switch in said casing, adapted for connection with said circuitmeans, and having an inactive position and. a power:-

enabling position, said reset, switch being normally in inactive position and being manually operated to power-enabling position whencsaidi limit switch is in-poweredisabling position, and, mechanical means controlled by said cam for; rev storing said reset switch to its normal position upon the return travel of said rod to its vnormal.

position.

EARLE F. RUETER..

nnrnanncas ci'rEi) Theiollowing references are of record in the file of'this patent:

UNITED STATES PATE nTs Date