US2600887A - Electric hoist - Google Patents

Description

J. P. LANNEN ELECTRIC norsw June 17, 1952 2 SI-EETS SI-IEET 1 Filed Aug. 7. 1948 i-iEt-ii-in:I- -r-I-Q-I-Q-I-EEan? I 3noentor Joseph P Lannfln r (Ittomeg June 17, 1952 Filed Aug. 7, 1948 J. P. LANN EN 2,600,887

ELECTRIC HOIST 2 SHEETS--SHEET 2 lnnentor Jbseph P Lannen (Ittorneg Patented June 17, 1952 Joseph P. Lannen Detroit,:Mich., assignorto Micro-roisennzineerine and Sales Com any. Detroit, Mic a par r h p Application August 7, 1948, Serial No. 43,063

. a 1 This invention relates to electric hoists and particularly controls for such hoists. In present practice, a switch box is carried by the hoist motor, the switch or switches therein being controlled by pull cords extending freely downward a definite distance. Inloading orunloading such a hoist and guiding a load, the operator has one hand available for that purpose, the other being occupied with the pull cords, since onethereof mustbe under stress" to keep the motor energized. h An object of theinvention is tornounta motor control box on the loadwarrying hook or its equivalent-,or onthe lift chain or cable inpronirnity: to the-hook, so that control may be-exercised andthe hook be manipulated by one hand of the operator, who may manipulate the load with his other hand. a r V In attaining the foregoing object, there is furthenderived the advantage that the point of manual control forthe motoris always substan tiallyat the point of loading or unloading, regardless of lift distance, the-controlbeing hence much more conveniently exercised than by pull cords.

Another object is to extend alongtheload-liftingf chain or its equivalent, such insulated conduotors as are essentialto a manual control of the motor exercised at or closely adjacent to the hook or other load receiver. 7 H

Another object isto secure said conductors to a lift chain without interference with the requisite travel of the chain on a sprocket wheel.

These and various other objects are attained by the construction hereinafter described and illustrated in the accompanying drawings, wherein;

Fig. l is a side elevational'view o f an electrically operated chain hoist incorporating my imprev ements.

Fig. 2; is an end elevational view of thesame.

Fig. 3 is a fragmentary view showing a portion of; the lift chain and a conductor cord carried by such chain. V v h Fig. 4 is a cross sectional view of the same, taken on theline 4-4otFig. 3. v

5 isasectional view taken on the line of Fig. 1, showing the main control switch for the hoist. I

is a vertical sectional view of a switch for. limiting upward travel of the load receiver, showing a control element for such switch on the lift chain. I v V a Fig. 7 as crosssectionalview of said chain, particularlyshowing said control element, and taken on the iine |l of Fig. 6.

4 claims. (cram-@135 Fig. 8 is aside elevational view of an electri cally operatedcable type of hoist, with my invention applied.

- Fig. 9 is a fragmentary. vertical sectional view taken on the line 9-9 of. Fig. 8, particularly showing'the cabledrum and its mounting.

- .Fig. 10 is a cross sectional view of thelift cablcof-Figs- 8 andwili taken on the line NIH-l0 ofFig.9. a

Fig. 11 is a diagram of the'electrical connections of my'improved hoist.

In' these views the reference character I designotes an electric motor, transmitting a drive through a train of speed-reducing gears 2, 3, 4, and Etc asprocket wheel 6. Said gears and sprocket wheel occupy'a casing I having a uni tary connection to the'motor casing, the resulting unit being surinountedby a supporting hook 3, A roller type chain 9, has one of its ends exteriorly secured at ID to the casing I, and'extends downwardly from such end 40 and then upwardly to the sprocket wheel, thus forming a sleek suspended loop. .Passing over the sprocket wheel, the chain extends downwardly a variable distance, terminating in a swivelly mounted loadreceiving-hook II. The construction so'far described is well known, my improved featurcsbeing' as follows: a

The hook H is detachably engaged by an eye- 4 let [.Zicrmed on a double hook H1 or some other accessory load receiver best suited to a required job. Fixed on one of the shanks of the hook i3 is .a main switch (see Fig. 5) comprising an'insulating casing l4, spaced upper and lower contacts l5 and. I6, and a spring arm I! fixed at one end thereof and biased to normally engage the contact IS. A push button la'engaging the free end ofthe arm [1 serves to disengage such end from the contact l5 and establish it either in a neutral mid position or in engagement with the contact 16. Three conductors 19 respectively connected to the respective contacts l5 and I6 and arm- I! lead through a suitable insulating cord 20 to a three pronged plug 2| which is engageable with a three socket receptacle 22 fixed on a mounting 23 attaching the chain 9 to the hook .ll. Three conductors, 24:12, and 241 incorporated in a suitable insulating cordZlz'extend respectively from the respective sockets of the receptacle 22 along the chain 9, following the. latter to a point adjoining its anchored end IO-and then leading ofi to a connection box 25 on the motor, as appearsin Fig. 1.

The cord 24a engages that face ofthe chain which clears the sprocket wheel 6 and is straddled by and held to such face by a suitable num- 3 ber of wire clips 26, having their ends welded or otherwise fixed on the links of the chain (Figs. 3 and 4). It is preferred to engage said clips with alternate links of the chain, as per Fig. 3.

Mounted upon and beneath the casing 1 are a pair of similar up and down limit switches 21 and 28, the 'up switch being detailed in Fig. 6. Each such switch comprises a contact arm 29 downwardly sprung into normal engagement with a fixed contact 30. The hook-carrying vertical span of the chain 9 carries a laterally projecting control finger 3| which, at a desired upper limit of load travel engages and lifts the arm 29 of the up limit switch. Downward load travel is similarly limited by opening of the "down switch by a control finger 32 (Fig. 2) fixed on and laterally projecting from the chain at a suitable distance from its anchored end.

Referring now to the electrical diagram (Fig. 11) it is first to be understood that same is illustrative of a control for a three phase motor I, although other types of motors with suitably modified controls are applicable to my purpose. Lines 33, 33a: and 33y lead from any three-phase power source into a reversing starter box 34 from which power lines 35, 35a: and 35g lead through the connection box 25 to the motor. Within the starter box, switches 36 exercise a unitary control of current delivery to the motor for one direction of drive, and switches 31 similarly control current delivery for a reverse drive. The switches 36 are operable by a control coil 38 for effecting up travel of the load and a similar coil 39 operates the switches 31 for lowering the load. A relatively low amperage control circuit derives current from the lines 33 and 331: through a transformer 40. Said control circuit is formed by the conductors 24a: and 24y connected in parallel, across leads from the secondary of the transformer 4B, the conductor 24 forming one of said leads and the other being designated 4|. The lead 24 is connected to the arm I! of the main switch, and the conductors 24:1: and 242 lead respectively to the contacts I and Hi. The conductor 249: includes the up limit switch 21 and control coil 38, and the conductor 24y includes the down limit switch 28 and control coil 39.

In use of the described hoist, when the push button I8 is free, the main switch arm I! engages the contact I5 and, if the limit switch 21 is closed, the up control coil 38 is energized, closing the switches 36. Hence the load hook assumes its upper limiting position, determined by'automatic opening of the switch 21. When the operator fully depresses the button l8, the arm I! engages the contact l6, and if the limit switch 28 is closed, the down coil 39 is energized closing the switches 31, and effecting a lowering of the load hook. When the latter is in loading position, the operator maintains a neutral position of the arm I! while applying a load to the hooks I3. He then releases the button, and the load is raised. Up travel may be terminated at any point through opening of the main switch, or the up" limit switch may serve to establish some desired unloading position.

In the modification shown by Figs. 8, 9, and 10, a reversible motor Ia drives a drum 42 through a train of gears 43 occupying a casing Ia. Upon said drum winds a cable 44 within which is centrally extended a conductor cord 45 comprising three conductors (see Fig. As in the firstdescribed construction, said conductors lead to a suitable. main switch Ida carried by the loadreceiving hook 13a. The electrical connections may be substantially as per Fig. 11, except that it is necessary, as appears in Fig. 9, to provide collector rings 46 on an end of the drum, and to engage such rings by brushes 4'! on a hanger 48 journaling an end of the drum shaft. The three conductors which extend from the drumanchored end of the cable are respectively connected to th respective collector rings. While a brake or brakes will be necessary to the improved hoist in each of its disclosed forms, such brakes are common and no attempt has been made to show same.

Location of an electrical control station upon or in a permanently close proximity to the load receiver greatly facilitates operation of the hoist as compared to present practice, it being much easier to apply a load when the operator may keep one hand on the hook, using the other to shift the load. Thus the hook and load may be presented to each other in the most suitable loading relation. By extending the conductors leading to said control station along the chain or other load support, they are kept out of the way. avoiding interference either with the operator or the load, and are safeguarded from damage.

What I claim is:

1. In an electric hoist, an electric motor, a sprocket wheel, a speed-reducing drive from the motor to the sprocket wheel, a. load-engaging element, a lifting chain carried on the sprocket wheel and supporting said element, a control switch carried by the chain in proximity to said element, and a control circuit for the motor including flexible conductors extending from the switch along the face of the chain which is outermost from the sprocket wheel, in passing over such wheel.

2. In an electric hoist as set forth in claim 1. a plurality of fasteners spaced longitudinally of the chain and straddling said conductors, the ends of such fasteners being secured to opposite sides of the chain.

3. In an electric hoist, an electric motor, a rotary lifting element, a speed-reducing drive from the motor to said element, a load-engaging element, an elongated flexible load-supporting connection from the lifting element to the loadengaging element actuable up and down by the lifting element, a control switch carried by the flexible connection in proximity to the loadengaging element, a control circuit for the motor including flexible conductors carried by the flexible connection and extended along such connection from the switch to the rotary lifting element, a normally closed limit switch fixed with respect to travel of said connection and included in said control circuit, means carried by said connection for opening said limit switch, upon a predetermined lifting of the load, a secondlimit switch fixed with respect to travel of said elongated connection, and means carried by said connection for opening the last-mentioned switch upon a predetermined lowering of the load.

4. In an electric hoist, an electric motor, a rotary lifting element, a speed-reducing drive from the motor to said element, a load-engaging hook, an elongated flexible load-supporting connection from the lifting element to the hook, the hook being detachable from said connection, a control switch carried by the hook, a control circuit for the motor including flexible conductors carried by the flexible connection and extended along such connection from the'switch to the rotary lifting element and passing over said ele- 5 6 ment in unison with said connection, a readily Number Name Date releasable electrical connection from the switch 1,413,094 Bergey Apr. 18, 1922 to the conductors. 1,473,606 Brandon Nov. 13, 1923 1,960,371 Cofiing May 29 1934 J PH P. L NNEN.

OSE A 5 1,978,753 Lent Oct. 30, 1934 REFERENCES CITED 2, 35,563 Lock NOV. 30, 1943 Th f 11 f f d h 2,432,411 G-uerjn et a1 Dec. 9, 1947 e 0 0W1ng re erences are 0 recox m t e 2,433,938 Vamer Jan 6 1948 file of th1s patent:

UNITED STATES PATENTS 10 FOREIGN PATENTS Number Name Date Number Country Date 681,941 Westbrook Sept. 3, 1901 651,316 France Oct. 9, 1928

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