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Publication numberUS1788302 A
Publication typeGrant
Publication dateJan 6, 1931
Filing dateOct 31, 1927
Priority dateOct 31, 1927
Publication numberUS 1788302 A, US 1788302A, US-A-1788302, US1788302 A, US1788302A
InventorsHummel Willard A
Original AssigneeAmerican Eng Co Ltd
Export CitationBiBTeX, EndNote, RefMan
External Links: USPTO, USPTO Assignment, Espacenet
Upper and lower limit switch mechanism for electrical hoists
US 1788302 A
Abstract  available in
Previous page
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Claims  available in
Description  (OCR text may contain errors)

Jan. 6, 1931 w. A. HUMMEL 1,785,302

UPPER AND LOWER LIMIT SWITCH MECHANISM FOR ELECTRICAL HOISTS Filed Oct. 31, 1927 3 Sheets-Sheet l a E @L y ii veicZ' ozw %Mazwej A y dl ivzeyq Jan. 6, 1931. w. A. HUMMEL 1,788,302

UPPER AND LOWER LIMIT SWITCH MECHANISM FOR ELECTRICAL HOISTS Filed Oct. 31, 1927 3 Sheets-Sheet 2 I l I I I l 1 I I I 1 l I zweznnri Jan. 6,1931. HUMMEL 1,788,3@2

UPPER AND LOWER LIMIT SWITCH MECHANISM FOR ELECTRICAL I IOISTS Filed Oct. 51. 1927' 3 Sheets-Sheet 3 Patented Jan. 6, 1931 'rrEe STATES P T- CE WILLARD A. HUMMEL, or PHILADEL'PHIA, PEN SY VANIA, AssIGNoitfToAMnnIoAN ENGINEERING COMPANY, or PHILADELPHIA, ianNNsYLvriNiA, A CORPORATION or PENNSYLVANIA nrPER'ANn LOWER LIMIT swi rcii MEcirA i sivi: ron amn on. HOISTS/ a 7 plication filed mm 31, 15,271, seria Ne. 236,111.

My invention relates to systems ofjcontrol for hoisting apparatus and the like.

stall limit-switch mechanism inthe pilot cir- 5 cuitof hoist control-equipment. The pilot circuit functions as an auxiliarycircuit to the main iiiotor-energizingcircuit, and it in cludes in addition to, the limit-switch mechanism, the push-button station which is controlled by the operator and also the energizing windings of the .contactors in the main ,inotor circuit. Such arrangement, however, has not proved entirel satisfactory in practice. For example, the contact pointsof the main contactorequipment very frequent- 1y fuse together, thereby permitting the continued energization of thezdriving motor,"

by the limit-switch mechanism.' .7 p

An object of my invention, therefore,is to provide a system of control which overcomes thedisadvantages characteristic of the pilotcircuit equipment,my invention contemeven though the pilot circuit has been opened plating the insertion of the limit-switches rectly in the main motor circuit. V

. Another object of my invention is to provide mechanism of'the character described,

wherein the positiveactuation of the limitswitches 1s assured by power derived from the hoisting drum; and wherein damage to the switch mechan sm is averted upon aypredetermined over-travel of the drum:

A further object of myinvention is toprovide a stop mechanism comprising a driving tion connection therewith, a third member adapted to be connected to the limit-switches, a fourth member, a wheel carried by the fourth member in such operative relation to the driven member as to be actuated bodily upon the initial movement of the driveninemmy'invention; i i ,1. Y i Fig, .is'an enlarged detail horizontal sectional view of the stop mechanism shown in member, a driveii'member having a lost-mopracticed, will be apparent more fully here inafter, When't'aken in connection with the accompany ng drawings, wherein, It has heretoforebeen the practice to in- Figjl 's a top plan view, partially irihorii zoi'ital section, of one form of embodiment of Fig. 1, the sectional plane being takenon the Figs. 3 and-.4; are endand side elevatio nal v ews, respect vely, of the structure shown in Fig. 2, the' severalparts being shown in Referring] to L'the mono-rail hoist the-rein shown comprises-a driving electric motorljra drum 2, which ismounted on a shaft 3;',gearing at which extendsibetween the motor 1 and'one end 50f a-drum shaft astop mechanism 6 which is operatively as sociated with janiopposite end? of the drum shaft 3; and a pair of limit-switches 8 and 9.

As shown in 5', these switches are respectively connected in conductors Hand 12,, which constitute a divided circuit portion of a 'main motor energizing circuit 13. The conductors lland 12- are connected toa pair of reversing jcontactors which serve to controltlie'direction of operation of the motor 1, andinay be controlled from a remote "point by the usual push-button station The latter, as well as the reversing contactors, havenot beenshown in order to simplify the description of my invention, it being deemed sulficient to vspecifymerely that when currents "are'supplied to the branch conductor portion 11 of the energizing circuit 13,

the motor 1 operates, say,1in"a directionto lift the hoisting hoolgand that when currentsjare s'uppliedto the branch conductor porti on. 12,fthe motor 1 is so energized as to operate in the opposite direction, that is, in a. direction tending to lower the hoisting hook, The limit switch]9,therefore,must' be closed in order for the motor to raise the hoisting hook, and the switch 8 must be closed for the motor to lower the'hook; and thisis the nor'mal position of these switches, all as Wi l appear more fully hereinafter.


Considering in I greater detail the stop mechanism 6, a shaft section 14 is provided with an enlarged head portion 15 which is adapted to be detachably secured to the end portion 7 of the drumshaft3 in any conven-- ient manner; rocker frame or flier 16 is provided at one end with an enlarged portion 17, which is journaled on an adjacent portion .18 ofithesh'aft sect-ionl i, and. a sleeve portion-19 which'gextends 'from'the'portion 17 into abutting relation to a shoulder 21 formed by the shaft head portion 15. An opposite end 22 of the'roclrer frame 16 is provided with a journal portion '23 which is mounted on an adj acent-sha ftportion 24of reduced diameter. A shoulder 25, which is positioned at one end of the shaft'portion 18,

afi'ords an abutment tending to prevent a movement of the frame 16=toward thejdrum' shaft 3. The movement of the frame 16 in the opposite direction may be preventedby a nut 26 which is mounted on a threaded end portion 27 of the shaft portion'24.

A portion28' of the shaftlsection 14 tween the bearing portions "18 and 24 there" of, is threaded for the reception of a travelingnut or cross head. 29 and a pair of adjustably spacedclutclrcollars 31 and 32. The spacing between the collars 31 and 32 is such thatthe drum'g2 may be moved through its maximum distancebefore a shoulder'33on the traveling nut 29 engages a shoul- 'der 34 on one of the collars 31, 32. 7 Since the travelingnut 29 is connected at the upper I and lower edges thereof by shoulder portions 35 and-36 to spaced parallel side portions 37 and 38 of the rocker frame 16, thecontinued turning of the drum shaft 3 andconsequently the shaft-section 14 causes a corresponding movement of the rocker frame 16. Thus, the rocker frame116 is actuated only when the travel of thedrum 2 exceeds a'certain value which has been predetermined by the spacing ofthe collars 31 and 32. V

The rotatable frame 16 may be returned to its initial position .shownin Fig. 2 of the drawing, when the traveling nut 29 disengages either ofthe coeacting clutch collars '31 and 32' due to the reversal of the drum '2, by means of a spring 39 which encircles the rocker frame portion 16. As shownin Fig. 4, opposite ends 41 and 42 of the centering spring .39 are positioned'on opposite sides of'lugs or shoulders 43 and 44. The lug 43 extends from a vertical base plate '45 which is secured to an adjacent portion 46 fof the hoisthousing in any convenient manner. The lug 44 issecured to the rocker frame 16, and it is disposed between the Portions of the spring ends 41 and 42 which are positioned intermediate the, .shoulder43 and the rocker frame portion'16L Hence,

t'heroclrer frame-or flier. constitutes a float- ,l g, sprung-center member with a lost-motion connection to the .d-rnn shaft I In accordance with my invention, movement of the floating rocker frame 16 from preferably provided with a beveled portion 53 having angled sides 54and55 terminating in a central peripheral edge 56. The enlarged portion 17Zof the floating rocker frame 161s provided with a complementary circular recess or groove 57, which is adapted to receive the beveled port1on53 of the wheel 48 and which constitutes acircular track in' frictional engagement. therewith.

As shown 1n 'Flg. 2, the c rcular groove 57 isprovided with an enlarged recess portion 58 which is. adapted to receive an adjacent portion '59 of thewheel 48,. affording aseat therefor, ,The position of the recess portion .58 is, suchthat the wheel 48 is seated thereon only when the rocker frame 16'is in the central position shown in the drawing. Should the rockerframe16 turn in either direction, then the wheel 48 is actuated out of the recess portion 5.8 duringthefinitial movementlpf the rocker frame 16'and thereafter it traverses the remaining track portion of-the groove 57 without causing a further bodily-movement of the wheel 48. There is thus. a lost-motion connection'bet'ween the rocker sleeve parts 47,48 and the floating frame 16. Therocker sleeve47 may be mounted on a shaft- 61,.oppositeends .62fand 63 of which are journaledin the loaseplate 45. anda plate portion .64 thereof. The movement oftherocker sleevej47 may be transmitted toa;

switch operating member 65 through multi- 'ilying linkage .66 whichis so-designed that a relatively small movement of the rocker sleeve 47 causes a relatlvelyj large movement of the switch operat ng member 65. As

illustrated in Fig.3,the linkagel66 com prisesfan arm67 extending downwardly from the-sleeve 47 afpairof links 68, andan arm 69 which is relativelyshort comparedwith the arm 67 and which also {extends downwardly from the switch operating member 65. The

member 6.5 ,may be mounted on a shaft .71, opposite ends of which 'are ournaled n a hub portion .72 of the base plate 45and the frame portion 64. T V

Since it is --.desir able, for reasons .as will presently'appear, to return automatically theswitch operating member. 65 the wheel 48 and: the intermediateparts to theneutrgl position shown in the draw ng,' 1mmed1ately upon the return of the rocker frame 1'6 .to. t s neutral position, a centering .spring 73 is, mallnted on the hub portion 72 of the base plate 45. I .Qpposi e end Hand 7 .01.6 t Spring .73 .err sers-1aarsewaswere track, of mechanism to be controlled, and

means for operativcly associating said meclianism and said driven membercomprising a rotatable element, the periphery of which is beveled, said track having acomplementary portion in frictional engagement. with said element. V V. i V

3. Stop mechanism for ho st ng apparatus comprising dr ving means, a'floating spr ng- .centered driven member havinga lost-motion connection therewith, a. second member adapted to actuate switch mechanism, :and

means extending between-said members com prising a rotatable element having a lost motion connection with said-driven member and linka e adapted to cause a rapid movement of said second member upon-the occurrence of a relative 'movementbetween said element and saiddriv en member.

4. Control apparatus fora hoist comprising driving means, afloating spring-centered driven membenhaving a lost-motion connection therewith, a second spring-centered floating member adapted to actuate limit switch mechanism, and means whereby said second member may have a predetermined movement only upon'the initial actuation. of said driven member,rsaid means comprising multiplying linkage, a thirdrotatable member connected to said linkageand an element positioned in frictional engagement ,with

said driven member and carriedbysai dthird member. e p

.5. Apparatus compr sing driving.mcans,a spr1ng-centered driven memberLhav ng a lost- 1notion connection therewith,, a second springrcentered member, a rocking .member,

means carried by said rocking member for causing a movement thereof'upon a relatlve' movement between said rock ng member and said driven member, and movement-multiplying linkage extending between said rocking member and said second spring-centered member. I p I 6. driving member, a driven member having a lost-motion connection} therewith, a

member also rotatable adaptedtoibe connected'to switch mechanism, a fourth rotatable be actuated upon a predetermined movement of said nut, a thirdmember adapted "to be connected to switchmechanism, a fourth member havinga rotatable mounting, an element carried by said fourth member and positioned in frictional engagement with. said driven .member, andi linkage extending be? fourth member and said'th'ird uponengagement of said nut with one of said I stops, a spring-centered member adapted to be connected to switch ',n1echanism, a fourth member also rotatable and'having such lostmotion connection tof'said driven member as to be actuated-thereby upon an initial movement of said driven member, multiplying means forfoperatively. associating said fourth member and said third member, so that a quick movement. of the switch mechanism may occur upon said initial movement. i

9; In astopmechanism forhoists, the combination with a driving member having a threaded portion provided with spaced stops and a traveling nut, of a spring-centeredfioating member so connected to said nut as to be actuated upon engagement of either of said stops with said nut, said driven member having a'circular track, a second spring-centered floating member adapted toibe operatively associated with switch mechanism, a fourth member havinga rocking support, an element U carried by saidfourthmember and positioned in such operative relation to the trackof said driven member as to be actuated bodily upon the occurrence of a predetermined movement of said drivenmember, and linkage extending between said fourth member and said second spring-centered member, whereby said bodily movement of the element may be imparted to said switch mechanism.

10. Apparatus of a character described comprising a driving motor, a main energizing'circuit for saidmotor having a divided portion respectively including limit-switches, adrum actuated by said motoryand operating mechanism for said switches efiective upon a predetermined over-travel of said drum. 11. Apparatus of the character described comprising a drivingmotor having a main energizing circuit with a divided portion adapted to permit reversal in thedirection of operation of said motor, limit-switches for said divided circuit portion, respectively, a drum connected to said motor, and means for causing the operation of oneor the other of said limit switches' depending upon the direction of over-travel of said motor.

12. In combination, a driving motor,a'main energizing circuithaving a divided portion adapted to permit reversal in the direction of operation of said motor, normallv closed limit-sWitches fOr said divided circuit. portion, respectively, a 'drum'connected to be ac; tuated by said motor, and means responsive to over travel .of said drlnnin ei herilirectien for causing the opening of at least one of said limit switches.

13. In a system of control for a hoist, the combination with a driving motor of a main energizing circuit for said motor having a divided portion adapted to permit a reversal in the direction of operation of said motor, normally closed limit-switches for said divicled circuitfportio'n, respectively, a drum 1 actuated by said motor, and means responsive only to the initial over-travel of said drum for causing the operation of one of said limitswitches. V

14. In apparatus of the character described, the combination with a driving motor and a main energizing circuit therefor provided with a pair of limit-switches adapted to cause an interruption in the operation of the motor in either direction, of a drum actuated by said motor, and means for causing the operation of at least one of said switches upon the overtravel of said drum, said means comprising a threaded shaft provided with spaced stops 7 and traveling nut, a fioating spring-centered. member havingsuch connection with said I nut as to be actuated thereby upon the engagement of said nut with either of said spaced stops, a second spring-centered floating member adapted to be connected to said limit-switches and means for operatively associating said first-mentioned spring-centered member and said second-mentionedspringcentered member so that at least'one of said switches may be actuated upon the voccurrence of a predetermined movement of said first-mentionedspring centered member.


Referenced by
Citing PatentFiling datePublication dateApplicantTitle
US2417434 *Feb 13, 1945Mar 18, 1947Bell Telephone Labor IncMechanical stop device
US5299678 *Aug 12, 1993Apr 5, 1994The Chamberlain Group, Inc.Limit switch mechanism for garage door opener
US6135421 *Oct 29, 1999Oct 24, 2000Mhe Technologies, Inc.Hoist with proximity limit switches
US6199325Mar 2, 1999Mar 13, 2001Irwin Seating CompanyPower system for extending and retracting a structure
U.S. Classification192/141, 254/276
International ClassificationH01H19/00, H01H19/18
Cooperative ClassificationH01H19/186
European ClassificationH01H19/18C