US2428578A - Load lifting control for hoisting apparatus - Google Patents

Description

Oct. 7, 1947. NELLES 2,428,578

LOAD LIFTING CONTROL FOR HOISTIN G APPARATUS Filed May 24, 1944 Patented Oct. 7, 1947 Logan; hrrrmd CONTROL FOR HQISTI-NG APPARATUS Russell E. Nelles, Millburn, N. J assignor to The Union Manufacturing: Company, New Britain, Conn, a corporation of Connecticut.

Application May 24, 1944, SeriaIN'o. 5372065- 5 Claims. (Cl. 25%113) invention althou h not lim in use to; any ec al. appar tua. s par i rly pplicable fon controllingv the. hoisting of loads. in power hoisting apparatus, and for this reason such. apparatus-has. been selected by me for the purpose. of illustrating the invention herein, and object. of my. invention, among others, is the provision of means: wherebyin a mechanism of this type embodyingan apparatus which is suspended from overhead in a more or-lessmovable and unstable condition and free to swing to a greater or lesser extent, certainty of control in the upper limit of its movement of a load being raised by the hoisting; mechanism may be assured irrespective of; its unstable condition regarding the support of the apparatus.

"Qne form of an apparatus embodying the invention and inthe construction and use of which the objects herein set out, as well as others, may be, attained is illustrated in the accompanying d w s n. W QhT- Figure 1 is a view inside elevation of one form or the; apparatus embodying my invention.

Eigure'Z isa top plan view.

Figure 3 is aviefwin section, on a plane denoted by the roken ine 3+3, of F 1.

Figure .4 is a side view on enlarged scale of the switch mechanism. as suspended from the rotating, drive. shaft,

Figure 5 is a view in section one plane denoted by the broken line 5?5 of Fig, 4,

'l i'igure 6' is a bottomview of the same.

Figure 7- a view-in side elevation of the sw tch, ke ndra m. i conne t m the es i; ha tt qturey Figure, 8 is aview in elevationoi a; length of the load; line on cable illustrating means. for all] s ab y nQ i ie ins-the. w nner. d sk his lso. be n .hWl:-

s re; deiailv ew i lust ating. the-ma eewiz dju ta le ositionin a rin disk to a cable,

Eigure 1Q. is: aviewi; similar to Fi 9-; but. looking from apoint of view; at-rrigh-tangles touthe pointof viewof Fig. 9.

While, as; hereinbefore. mentioned, this invention is.,n otlimitedtoxuse. withany particular type; of; apparatus, it ispeculiarlyadapted for use in connection with power operated hoisting mechanism, such as is embodied in my patent for such mechanism issued-April 24; 1945; 'No. 2,374,- 450 to'which'patent reference-ishereby made for a more thoroughunderstanding or its method 2; of application to the apparatus disclosed herein.

In the accompanying drawings the numeral 6 denotes afragment of a housing such as is shown in my patent just mentioned and within which driving mechanism operated by an electric motor is housed, the entire apparatus being suspended by any suitable means from overhead supports in a manner that will be readily under stood by those skilled in the art and acquainted with the use of such mechanism and as especially disclosed in my patent above named. This driv ing mechanism comprises a driving shaft H] which is connectedwith the hoisting mechanism in any suitable manner, this, hoisting mechanismbeing enclosed in ahousing. comprisingtwo housing; members 89, the mechanism therein being partly omitted as notbeing. essential to anunderstanding of the invention and. which may be: suspended. byhooks I.

In the use of the-mechanism of this. type it is essential that means be provided for automaticallycontrolling particular-1y upward movement ofa load; being raised-by the hoisting mechanism so that all danger of; the load hook colliding with the housing or hoisting mechanism will be removed and at the same time it is found d'esirable in some cases to provide means-for locatiing the power drivingv mechanism at different distances from the hoisting mechanism, as by/ lengthening of the driving shaft I0; Suitable: means commonly. employed for automatic con-- trol of upward hook movement to avoid overwinding of the-hook at the topof'the lift embody; electric switches-which by contact of the hook: with a controlling member will operate to shut offthe power from theelectric motor.

In accomplishing this purpose I provide a. switch supporting bracket comprising a switch. housing H in which the electric switch mechanism is contained, this housing. having sup porting ears l2. at oppositev ends thereof which. arebored for rotatable'mounting. upon. the driv-- ingshaft Land a collar l3 secured to the driv ingshaft locates the switch against movements inone; direction and a hub l4 of, aspider I5 to be more, specificallyhereinafter" described lim its, movement in an opposite direction. It will. be understoodthat-theswitch is wired for elec trical connection with the motorin a manner" that. will bev readily understood. and for which reason: a more specific. showing, and description. areomitted'herein.

"The-switch comprises? anactuating-plunger I 8 into generally U-shape having substantially parallel sides with the free ends of said sides extending through a tripper arm supporting bar 2|, said bar being pivotally mounted for limited swinging movement in a horizontal plane on a tripper arm supporting stud 22 secured to andv extending downward from the switch actuating lever IT, as shown in Fig. 4. This tripper arm is curved diagonally downward and also extends horizontally to vertically underlie the space be-' tween the hoisting housing members 8-9 whichoperation of the electric switch, and this r-- siliency is enhanced by the pivotal mounting which enables yielding movement of the arm in both horizontal and vertical planes, and there is therefore little liability to injury of any of the parts comprising the switch and its connection with the load line. The term fload line is used herein to describe any flexible member'whether it be cable, chain, rope or other device of any similar character.

In the operation of the device, as will have been fireadily appreciated by those skilled in the operhouses the hoisting mechanism, a portion only of which designated generally by the numeral 23 is shown herein and which comprises a load line or cable 24 as found in the hoisting mechanism of my patent hereinbefore referred to. A tripper disk 25 is mounted on the load line 24 above the load hook underlying the tripper arm, this disk being of a diameter greater than the interval between the sides of the tripper arm, said disk being mounted on the load line at such point that it will make contact with the tripper arm at a location to raise said arm to actuate the switch before the hoist hook reaches a dangerous position with respect to the hoisting mechanism housing.

From what has now been said it will be seen that the switch housing which requires to be supported in a substantially stationary position nevertheless makes use of a rotatably mounted member, to wit, the driving shaft ID and this mounting arrangement is so constructed that the power housing may be located at such distance as may be desired from the hoisting mechanism. The tripper arm 29is of light spring construction whichis permitted by reason of the pivotal supports for said arm and the switch actuating lever 11, and this produces a contacting arrangement between the lever and the load line or cable such that there is no liability of undue or sudden jar or strain being transmitted to any of the parts whencontact of the tripper disk 25 with the arm 2 0 takes place. 7

The main purpose of this invention has to do with a hoisting mechanism in which power is employed for operating said mechanism and I have therefore so arranged the parts that in cases where hand operated hoisting mechanism is employed this improved power operated equipment may be connected with and attached to conventional hoisting mechanism in common use with little trouble and expense as hereinbefore explained and which enables the power operated mechanism to be suspended adjacent the hoisting mechanism in a mannerherein illustrated and as further disclosed in my patent hereinbefore referred t0. 7

Attention is particularly called to the construction and mounting of the tripper arm which comprises an important feature of the invention and which, because of flexible and resilient characteristics, reduces to a minimum any chance for injury to the mechanism comprising the switch and its connection with the load line or hoisting cable. The double length construction of: the tripper arm enables'such arm to be composed of comparatively small spring wire imparting extreme resiliency and a yielding characteristic under excessive strains, and yet at the same time having rigidity enough for the eifective action on and ation of hoists of this type, apush button or other well-known device for opening and closing an electric circuit having been operated in connection with the power driven apparatus, the shaft ill will be rotated to operate the hoisting mechanism and the load line 24 with a load on the hook at the lower end thereof will be raised by the hoisting mechanism. This upward movement of the load line will continue until manual operation of the switch for controlling the power unit is effected: If, however, by inadvertence, accident, or mistake, this manipulation of said switch does not take place, theload line 24 will continue its upward movement until the disk 25 comes in contact with the arm 20 and the latter being raised as to its outer end the electric switch I I will be operated to. open the power circuit, thereby stopping the movement of the load line 24 before the hook comes into contact with the hoisting mechanism to the injury thereof.

The foregoing as described-relates to a secondary or emergency control whereby carelessness or thoughtlessnes s on the part of the operator is automatically corrected to the point of stopping the hook at a definite predetermined position in the lift. Cycle of operations is as follows: Power mechanism is normally controlled by conventional controlling means, in this instance referring to a primary control, but in an emergency the secondary or emergency control becomes effective. and will automatically stop the hoist hook as described. When the operator lowers the hoisting hook the tripper'disk drops away from the tripper arm thereby caus ing the switch mounted on the shaft l0 to again resume a normally closed position. This provides a closed circuit for the operator to resume hoisting operations. v

Under certain conditions it will be "essential that the position of the tripper disk 25 on the load line or cable 24; may be fixed in different places on such load line and I have therefore pro vided particularly eflicient means for accomplishing this purpose, this being particularly shown in Figs. 7 and 8, this adjustable positioning means being omitted from a showing in Fig. 1 as it will be readily understood how it may be applied to such structure. This fastening comprises abolt 26 which is inserted through one of the -'links'of the chain comprising the load line 24 and with a nut 21 applied to. the .boltin.a.man'ner common to structures of thissort. .v With this arrangement it will readily be seen that the disk 25 may be placed in anyposition along the load chain or cable and the tripper disk 25may therefore'be, readily placedin any posi-' tion desired, 7 V v I i In a similar device, shown as securing a; positioning disk ,28 to a load linein the form .offa. cable in Figs, 9 and1110 a hub 29 is formed, on the under side of the disk 28 and a boltand nut assembly 31 are used for clamping the disk in any position desired along a cable 32.

I claim:

1. In power-driven hoisting mechanism, wherein a power unit with its power supply and control equipment and a hoisting unit with its hoisting mechanism including a load line are operatively connected in spaced-apart drive relation by a rotatable drive shaft the respective end zones of which are operatively connected with said units to form an assembly adapted to drive the hoisting mechanism from the power unit, the combination with such assembly, of an instrumentality operative to render the power means inactive under predetermined operating conditions, said instrumentality being normally inactive and being rendered active when the load line reaches a predetermined position within the hoisting range, means for mounting and supporting said instrumentality on said drive shaft in a definite position intermediate of and spaced from said units with the instrumentality mounting free from rotation with said shaft and free to swing thereon to permit free pivotal drive movement of the shaft, the instrumentality including a tripping element extending into the path of travel of the load line and normally permitting free movement of the latter, said load line carrying a definitely-positioned member movable with the load line and co-operative with the instrumentality to render such instrumentality active to cause inactivity of the power unit when the member reaches such predetermined position.

2. A combination as in claim 1 characterized in that the power unit includes an electrically-driven prime mover and its controls, and the instrumentality includes a switch electrically related with the prime mover controls, said switch b'eing normally inactive to afiect prime mover activity and being automatically active to affect such prime mover activity through movement of the tripping element by the load-line member when the latter reaches the predetermined position in the hoisting range.

3. A combination as in claim 1 characterized in that the drive shaft carries spaced members fixedly-positioned onand rotating with the drive shaft, said instrumentality including a casing having a pair of ears mounted on said drive shaft between said members with the latter defining the position of the casing in the length of the shaft, said casing ears being freely mounted on the shaft to thereby permit freedom of shaft ro- 6 tation while. retaining the instrumentality position.

4. A combination as in claim 1 characterized in that the tripping element is of elongated loop form for normal free movement of the load line therethrough with the loop mounted for pivotal movement on a vertical axis, the element being formed of spring metal to provide normal control action under load line member co-operation therewith and to permit element yield in the presence of over-running conditions of the load line.

5. A combination as in claim 1 characterized in that the instrumentality includes a pivoted actuator mounted on a horizontal axis and with one arm co-operative with an instrumentality switch to make and break a circuit to the prime mover controls of the power unit and having another arm providing a support for the tripping element, said tripping element support including 'a pivotal connection between the arm and element on a vertical axis, said element being of spring metal formation to thereby provide normal control action by the actuator under load line member co-operation with the element and permitting element vertical yield in the presence of overrunning conditions of the load line, whereby the tripping element is free to swing on its vertical pivot to compensate for swaying or the like of the load line and preserves the normal control action and vertical yield regardless of such swaying or other movement of the load-line.

RUSSELL E. NELLE'S.

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

UNITED STATES PATENTS Number Name Date 761,884 Hardin-g June '7, 1904 997,934 Poque July 11, 1911 1,938,071 Hummel Dec. 5, 1933 2,325 429 Schreiber July 2'7, 1943 2,335,568 Lock Nov. 30, 1943 2,374,450 Nelles Apr. 24, 1945 FOREIGN PATENTS Number Country Date 290,041 Great Britain May 10, 1928 493,510 Germany Mar. '7, 1930 806,270 France Dec. 11, 1934

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