US2340409A

US2340409A - Chain hoist

Info

Publication number: US2340409A
Application number: US406036A
Authority: US
Inventors: George W Benjamin
Original assignee: Continental Gin Co
Current assignee: Continental Gin Co
Priority date: 1941-08-08
Filing date: 1941-08-08
Publication date: 1944-02-01
Anticipated expiration: 1961-02-01

Description

CHAIN HOIST Feb. l, 1944. C.;l BENJAMlN 2,340,409

CHAIN HOIST Filed Aug. 8, 1941 3 Sheets-Sheet 3 mvENTnR l .man se: w. BENJAMIN Y L7 ffm? ATT' HNEY Patented Feb. 1, 1944 HQISTR,

`George W. Benjamin, Birmingham, IAla., assignoi' to Continental Gin Company, acorpo'ratin of Delaware Application August 8, 194i,` Serial No. 496,1136

4 Claims.

My invention relates to a chain hoist of the type embodying a' 'ratchet 31H51. leve? mechafnm for advancing` or retractingl a chain, one link at a time, ina suitable guicleway, andl in particular is an improvement' n the hoist described and claimed in my prior Patent No. 2,227,893, issued January 7, 1941.

The principal object of my inventionis to provide a simple, sturdy hoist of the character described which shall have improved operating characteristics over that of my prior patent.

In my prior patent aforesaid, I employ an 'operating lever pivoted on the'body ofthe' hoist and I pivotally mount a pawl Aon each side of the pivot point of the lever, they pawls being adapted to'engage the links oi a chain alternately to advance or retract it with respect to the body of the hoist. The pawls are biased towardthe chain when lifting and are Vso vshaped that when one pawl engages aflinkto advance it, the other pawl isH caused to disengag itsA associated and permit the lchain"to advancef While the apparatus of my said patent'` is entirely successful in operation, it has""the disadvantage that it is double acting and theoperator must change his stance for eachv change of direction of movement of the lever.' That is,fin lifting a load theoperator must' raise the operating lever on one stroke and pull it` downwards on the next stroke,v with an equal load in each direction, which operation is awkward and difiicult, particularly in handling heavy loads. e"

In accordance with my present invention, I employ `a hoist body similar'to'that 'of my prior patent with an oscillating lever pivotally mounted thereon. Instead of mounting both pawls on rthe operating lever, I mount one on the lever and one on the' body of the hoist. The pawls are resiliently connected to bias them towards the hoist chain. With only one pawl movable with respect to the bodyof the hoist, the chain is advanced only upon movement of the lever in one direction. When the lever is movedA in the opposite direction, the paWl mounted onV the body of the hoist holds the 'chain while the' novable pawl engages another ,link tot the chain. The

apparatus may thns be `,operated byexerting force in one direction only on the operatinglever. With a vertical lift, the work lstrokeis made downwards, and it will at once be apparentftlat this is a distinct loads.

Apparatus embodying features of my invention is illustrated in the accompanying--drawin'gs forming a par# of this appucanenin' whiehfff `50 advantage in handling refait Fig.v1 is a View partly in section and partly 1in elevation Showing'my imprwed heist; Fig. 2fisA a sectional view taken along the line lII--lI 'of'Fieflf fig. 43 is a sectional elevation taken at right angles to Fig. 1,; ""Fig, 4 'is` a fragmentary elevation of the hoist showingfit arranged"forretracting the. chain;

A1'i`g.'5 is a sectional view drawn to a larger scale" showing the action of the hoist in retractfingmthe'chain `at the moment before load is tf Sierre@ fieri the' holiieg rawl' i@ ,the 'lifting bet/1:

1li-igt 6 is an elevational view of the holding pawn i f `F`ig. `'l is an elevational View showing the action ofthe hoistfinlowering .the chain at the moment before load is transferred frorn'the lifting Vpawl to the holding pa'wl andshowing the lifting bliant/l in "fotted position after the load is transferred; and ""Iig. 8 is a View showing the positions of the pawls whenlovveringthe'chain and when the operating lever is in"horizontalpositiom Referring to the'drgwing'sfr'a better underfstanding of my invention, vIfny improved hoist zormrises"a ldody Ill'prvided with 'a sustaining hook Il." Formed in the body I0 isa guideway ll2 for a chain I3'. 'lllhe chain I3 may beY of th flat, or'ladder type as shown, with cross pins f4 'connecting the 'separate links, crit may be' `of anytsuitable type "which may be engaged by a ypaw-l and advanced in the manner hereinatte'r described. U'Ihe lower end of the chain |3`l's adptedjto be attached tothe workV as by a hook 16', partiauy shown irl Fig. `1'. .Bivotal'ly mounted on the body I0 is an operating lever lihaving 'arms I8' andy AI9 straddling thebody Il) and pvted `on pins' 21| `and 22 which may ,befbosselsformed on' thesides of the body. A lifting pawl 23`is"pivoted at one vend 24 tothe arms la `and le of the operating lever l1, and egitends npwardl'y,A as `viewed in thedrawings, ,aloA id e the body A finger 2B formedl 6h th pay/1 z atxtends through 'an opening'zi thfe body .td engag a cross pin i4' of the chain Icaria ,move meenam witninthe body responsive to downward movement of the lever Il. 'Ihe underV side ofv the finger' is inclined at Z8ffto cause it to engage Athenext' 'lower cross pin |14 and be moved out of the body l0,"uDoIn nievement of the ieyef l1 inthe opposite dimentico j` Eormed' on' ther body ID onthside OOSite the`,pawl"23 area pair of lugs 294 between' which is pivoted ,a Asecon@ `or locking new.; 3l" Wbih 'is similar in configuration to the pawl 23 and which is provided with a finger 32 adapted to enter the body I3 through a suitable opening at 33 and engage a cross pin I4 ofthe chain I3 to hold the chain in any set position. The pawl 3| isk also provided with an inclined face 35 which, upon upward movement of the chain I3, as viewed in Fig. 1, causes the pawl 3| to be moved outwardly of the body il and assume a position to engage the next cross pin when it comes into position just above the finger 32.

Carried by the pawl 23 is a pin 34 and carried by the pawl 3| is a pin 36, which pins are connected by a spring 31 which normally biases the pawls 23 and 3| inwardly of the body of the hoist to engage the cross pins I4. As so far described, when the operating lever I1 is raised from the position shown in Fig. 1 of the drawings, the pawl 23 moves downwards while the finger 32 of the paw13| engages a cross pin I4 of the chain |3 to hold it in position in the body I0. The finger of the pawl 32 engaging the next lower pin I4 causes pawl 3| to ride over that pin and when it has passed the pin it is pulled into position beneath the pin by the spring 31. If the operating lever be now pulled downwards, the finger 26 engages the last mentioned pin I4 and moves it upwards, while the pawl 3| pivoted to the side of the body I3 of the hoist is disengaged from the next lower pin I4 and is caused to move outwardly of the body I3 by the approaching pin I4, to engage it as soon as it passes above the finger 32. The chain and its load is thus raised a link at a time by oscillation of the operating lever l1 and the pawl 3| acts to hold the chain in itsraised position while the operating lever I1 is being moved upwards to engage another link. Fingers 38 and 3Q on the opposite ends of the pawls 23 and 3| respectively serve as a means to disengage both pawls from the chain I3 when getting ready to operate and it is desired to move the chain through the body a considerable distance without oscillating the lever |1.

Mounted on one side of the lever I1 and secured Vthereto preferably by welding is a plate 4| having an oblong opening 42 therein with a notch 43 in the plate giving access to the opening. Disposed midwayoi the ends of the spring 31 is a T-shaped member fill with the head ofthe T within the coils ofthe spring 31 and the shank 46 extending outwardly through the coils. When raising a load with the hoist, as just described, the shank 45 of the T is turned to the position shown in Figs. l and 3, that is, out of engagement with the sides of the opening 42 in the plate 4|. When it is desired to lower a load gradually, the pin 46 is turned to the position shown in Figs. 4' and 5 of the drawings, with the shank 46 passed through the notch 43 into the opening 42. The shank 43 can be thus entered when the lever I1 is moved to mid position and will be engaged by the end of the opening i2 to compress one end of the spring 31 when the lever I1 is in its lower position. With the shank 43 of the T-member `44 in the opening 42, and with the operating lever ZI1 in the position shown in Fig. 5, it will be seen that the end of the spring 31 attached to the pawl 23 is in tension while the other end attached to thepawl 3|, is incompression, tending to push thejflnger 32 of the pawl 3| out of engagement with the cross pin I4. At this moment in the cycle' of operation, the finger 32 is held in engagement with cross pin I4 by the weight of the load von said cross pin.

If the lever Il be now 'moved downward slight- Cil ly from the position shown, the pawl 23 will raise the chain enough to release the engagement of thenger 32 of holding pawl 3| with its associated pin I4 and the pawl will be moved out of engagement with the chain by the spring 31, permitting the chain to be lowered by gravity as the operating lever I1 is raised. See Fig. 8. As the lever I1 is being raised, the engagement of the left end of the opening 42 with the shank 46 is relieved. See Fig. 5. The end of the spring -31 attached to the pawl 3| is again put in tension and pulls the pawl inwardly of the housing I to engage with the next higher cross pin I4,

i thus lowering the chain I3 one link.

At the saine time, as the lever I1 approaches its highest position, the right hand end of slot 42, as viewed in Fig. 7, engages the shank 46 and places the left end of spning 31 in compression. As soon as the lever has been raised suiiciently for the holding pawl 3| to engage the adjacent descending pin I4v and take over the load, thepartrof spring 31 in compression acts on lifting pawl 23 toY move it outwardly of housing Iii and out of engagement with the chain, as shown in dotted position, Fig. 7. The lever I- may now be lowered and spring 31 will hold lifting pawl 23 out of engagement with the chain until it has passed the pin I4 with which it has been engaged, at which time the slot 42 will have moved out of engagement with shank 46 permitting spring 31yto pull pawl 23 back into the housing to engageY with the next higher pin Ill, asA shown in Fig. 8.

While in the description herein the action of the hoist has been described as when raising or lowering Va load, it will be obvious that the action is the vsame when acting on a horizontal pull as when stretchingV or loosening a wire or cable.

From the foregoing it will be apparent that I have devised' an improved chain hoist which is simple and sturdy of design and which is easily operated without the operator being obliged to change his position during the operation.

While I have shown my invention in but one form, it will be obvious to those skilled in the art that it is not so limited, but is susceptible 'of various changes and modifications, without departing fromV the spirit thereof, and I desire, therefore, vthat only suchV limitations shall be placed thereupon as are spccically set forth in' the appended claims.

What I claim is:

1. A'chain hoist comprising a housing, a chain nrovably mounted in the housing and adapted for attachment at one eridto a load, a locking pawl pivotally `mounted on the housing and adapted tol engage "the chain and prevent retraction thereof, a lever pivoted to the housing, a pawl pivoted to the lever and adapted to push the chain through the housing when the lever is osciilated, andY aV spring for biasing the pawls toward engagement with the chain, and means adapted to coact with the spring and the lever alternately to effect disengagement of said pawls when retracting the chain'.

'2. A chain hoist comprising a housing having a longitudinally extendingy guideway, a chain movable through the guideway and adapted for attachment at one end to a load, alocking element pivoted to the housing and having a portion adapted to engageV the chain and prevent rearward retraction thereof, an operating lever, pivoted to the housing, apawl pivoted to the lever and adapted to feedthe chain through the guideway upon oscillation of the lever, a spring con# nected to the locking element and the pawl and biasing them toward engagement with the chain, and means associated with the spring and the lever for exerting force alternately on the locking element and the pawl to disengage them a1- ternately from the chain during lowering operation.

3. A chain hoist comprising a housing having formed therein a longitudinally extending guideway, a chain slidable in the guideway, a pawl pivotally mounted on a side of the housing and adapted normally to lock the chain against rearward retraction during operating, a lever pivoted to the housing, a second pawl pivoted to the lever and engaging the chain on the side thereof opposite to the rst mentioned pawl, said second pawl being adapted to push the chain through the housing upon movement of the lever about its pivot, a spring to bias the pawls into chain engaging position, a member carried by the spring and engaging the coils intermediate the ends, said member being movable into the path of the lever, and means on the lever adapted to coact with the said member to exert a force alternately on the locking pawl and said second pawl to disengage them from the chain during lowering operation.

4. A device of the character described comprising a housing having formed therein a longitudinally extending guideway, a chain movable in the guidewatr and adapted for connection at one end to a load, a pair of pawls entering between the links of the chain on opposite sides thereof, means to pivotally mount one of the pawls on the housing, an operating lever pivoted adjacent one end to the housing and having a handle portion and an extension portion, means to pivotally mount the other of said pawls on the extension portion of the lever, means for biasing said pawls into chain engaging position, and

` means responsive to operation of the lever during `lowering operation to engage the biasing means and eiect alternate disengagements of the pawls therefrom.

GEORGE W. BENJAMIN.