US2261963A - Free-chain hoist safety and reversing device - Google Patents

Description

Nov. 11, 1941. F.'W. CQFFING 2,261,963

FREE'CHAIN HOIST SAFETY 'AND REVERSING DEVICE Filed Jan. 28, 1959 2 Sheets-She't 1 INVENTOR, fifmlP/c/rhf ('OFF/IVG Patented Nov. 11, 1941 UNITED STATES PATENT OFFICE FREE-CHAIN nols'r SAFETY AND REVERSING DEVICE Fredrick W. Cofi'ing, Danville, Ill. Application January 28, 1939, Serial No. 253,379

2 Claims.

This invention relates to a free-chain hoist and of the character illustrated, described and claimed in my prior patents No. 1,591,362 dated July 6, 1926, No. 1,937,331 dated November28, 1933, and No. 1,862,331, dated June 7, 1932.

The hoist disclosed in each of said last two patents includes a two-part housing, an operating handle and handle carried control, a load chain, a chain sprocket, a reversing ring structure, and a control therefor.

All of the objects and features set forth in the introductory matter appearing in column 1, page 1, of each of the beforementioned patents applies to this invention as well.

The present invention relates to improvements thereof, and is particularly directed to safety features and reversing features as hereinafter pointed out more fully.

The full nature of the invention will be understood from the accompanying drawings and the following description and claims:

In the drawings, Fig. 1 is a plan viewof the interior of one housing portion with the control mechanism supported thereby.

Fig. 2 is a similar view of the complementary housing portion with operating handle attached, and with the load chain, chain sprocket, and operating and control mechanism supported thereby.

Fig. 3 is a side elevation of the exterior of the housing portion shown in Fig. 2 with the handle omitted and showing in detail the reversing ring structure and its immediate control.

Fig. 4 is a view similar to Fig. 3 of the reversing ring structure in another position. v

Fig. 5 is a sectional view taken on line' 5-5 of Fig. 1 and in the direction of the arrows and of the reversing ring control.

In Fig. 2 only a portion of the handle is illustrated. It is to be understood that the handle is substantially similar, except as now pointed out, to the handle structure, shown in detail and in Figs. 4 to 6, inclusive, of Patent No. 1,937,331. Herein the numeral 6 indicates the major portion of the handle, 1 a reciprocating rod controlling mechanism for tilting the pawl 8 pivoted on the shaft 9, and normally constrained by the spring l into engagement with the ratchet l6 carried by the shaft I 2 supported at opposite ends by the two housing portions l3 and I4, portion 3 being shown in Fig. 2 and portion 4 being shown in Fig. 1.

In this form of the invention, the pawl 8-see Fig. 2--is provided with a notch which engages opposite sides and nests; as it-were, the

crest portion of the adjacent ratchet tooth of the ratchet l6 carried by said shaft l2. This formation also insures that the handle pawl 8 engages two ratchet teeth increasing the safety factor at this point by approximately The handle also supports a reciprocating plunger I! which is to all intents and purposes, substantially identical to the plunger structure shown in Fig. 4 of the patent last mentioned, and is similarly operable, is similarly constrained and is similarly associated, broadly speaking, with other parts of the hoist, as set forth in the aforementioned patents. It may be briefly-stated that axial movement of the plunger shown in Fig. 2 in a direction away from the observer automatically tilts the pawl 8 from ratchet tooth engaging position into the non-engaging position.

In view of the complete disclosure of this handle structure in the before mentioned patent, no further detail disclosure or description is believed necessary herein for an understanding of the invention, although hereinafter the purpose of the notching of the handle carried pawl 8-see Fig. 2again will be referred to.

The body portion |3see Fig. 2is also illustrated in Fig. 3 in elevation and includes thereon external handle stops Ito and |8b. Thisis comparable to the stop 33, et cetera, shown in Fig. 2 of both'prior mentioned patents and the purpose of said stops is the same as set forth in said patents; wherefore, no further description thereof will be given herein.

The two housing portions I3 and I l-see Figs. 2 and 1, respectively, when suitably connected together by suitable means |9see Fig. 3-provide an upper closed chamber 20, see Figs. 1 and 2, and a lower and laterally ofiset chamber 2| with an angular chain passage 22 therebetween. This arrangement is similar to that shown in both patents. The chamber 2| communicates with the channel 22 adjacent the vertex of the angular channel shown most clearly in Fig. 1 and as shown clearly in Fig. 2, the sprocket II has a portion exposed in said channel 22 and an opposite portion exposed in said chamber 2|. Herein the sprocket includes but half the number of teeth as the ratchet Hi.

In the before mentioned patents but one sprocket engaging load sustaining pawl is illustrated. In the present invention-see Fig. 2a purality, and herein two-of said pawls are illustrated and since said pawls are substantially identical, a description of one will suffice for an understanding of both. It is to be observed, however, that the two pawls do not simultane ously seat in the roots of the sprocket teeth but are so positioned in angular relation to each other that each sprocket engaging pawl alternately engages or seats in a sprocket tooth. This provision insures that in the event of failure of one pawl due to pawl breakage or sprocket tooth breakage, which might-but never has occurredwould permit the other pawl to immediately engage an adjacent sprocket tooth and hold the load. The possibility of failure, however, is chiefly due to the failure of the constraining means for said pawls and in the event there be such a failure, the other pawl will hold the load, it being obvious that constraining means failure of both pawls will not occur simultaneously.

It will be observed that the ratchet has twice as many teeth as the sprocket so that with two interior load holding pawls 23, the handle 6 need only be moved through half the are shown in the before mentioned patents in order to elevate the load step-by-step. The amount of elevation per step, however, is but half that disclosed in the patents. Of course, for full stroke handle movement, the amount of load elevation remains the same.

In addition to the safety factor mentioned hereinbefore, use of two pawls 23, anguarly offset and alternately engageable, permits use of this form ofthe invention where clearances are so small that only half the arc of handle travel can be effected. With the prior patented structures, the hoist would not elevate in the clearance. The present hoist, however, when working in such limited areas, will function. This feature of operation is particularly useful on shipboard where free space is at a premium and extremely limited or in a maze of wire'circuits on a wire support such as a pole with many and differently directed crossarms thereon resulting in limited hoist operating areas.

Herein-see Fig. 2num'eral 23 indicates the lower pawl pivotally mounted by the shaft 24 and a spring 25 having one end anchored as at 26 is associated with portion 21 of said pawl and normally constrains the pawl into sprocket tooth root seating engagement. The other pawl structure' is similarly indicated by like numerals.

Mounted in the chain passage 22 is asprocket chain 28. The hoist structure is supported by a suitable hook structure, such as shown in the two patents mentioned hereinbefore and 'said hook structure is operatively associated with the body portions and in the complementary formation 29 thereofsee Figs. 1 and 2.

As disclosed in the beforementioned patents, rotation of the handle clockwise-see Fig. 2- rotates the ratchet and since the ratchet and sprocket are rigid with the shaft 12, the chain 28is caused to move upwardly through the channel 22 and thus elevate the load. In this'movement, the sprocket ratchets with respect to the two load locking pawls 23 and alternately by reason of their angular offsetting.

At the end of the elevating movement, the load is held by one of the twoload holding pawls 23, when the operating pawl 8, see Fig. 2, is released from its ratchet tooth engagement.

Following release of this pawl 8 from its ratchet, the handle is rotated counterclockwise and-pawl B is dragged over the top of ratchet l6 until it is repositioned for additional load elevation by spring l0. Rotation of the handle 6 clockwise-see Fig. 2-secures additional elevation of the load. This operation is repeated as often as necessary. By actuation of the red I or by axial movement of the plunger H, as before set forth, free chain operation is obtained. For positioning the handle 6 upon the opposite side of the hoist, only plunger I! is actuated.

To prevent axial play of the shaft 12 and retain same in the hoist body in place of certain locking mechanism, and the like, such as shown in the before mentioned patents, the wall 22a-see Fig. 2-terminates adjacent the upper mouth of the channel 22. An extension 30 of said wall 22a, is suitably secured as at 3| to the body portion l3. It includes a reduced portion 32 that is interposed between the sprocket H and the face of the body l3 that forms one side wall of the channel 22 and the chamber 2|.

'Reference now will be had more especially to Figs. 1 and 5, wherein a certain control mechanism is illustrated and the same is described previous to the description of the present reversing ring arrangement shown in Figs. 3 and 4, in order that the latter may be described and the operation thereof set forth simultaneously.

In the chamber 20 is mounted a stud 34 which by reason of its threaded connection as at 340,, may be adjustably secured therein. This stud supports a pin 33 which serves as a pivot and bridges the ga 31 or slot in the free end of the member 34. A strap type lever member 35 is seated in said slot and is pivotally supported by said pin 35. It is normally constrained in the position shown inFig. 5 by means of a spring 38 coiled about pin 36 as at 39 and having one hook end anchored as at 40 upon the stud 34 and the other hook end anchored as at 4! upon the strap lever 35.

- The housing l3 includes an aperture 42, see Figs. 2 and 5, and slidably supported therein is aplunger or pin 43, the upper end of which is slotted as indicated at 44 to straddle one end of the lever member 35. The two are connected together by means of the pin 45 or the like.

The housing I4, see Fig. l, is apertured as at 46, see Fig. 5, and slidably mounted therein is a plunger 41. A cotter key 48a or the like, extending through an opening 4 in the member 41 limits the outward movement of said plunger 4'! due to the-constraint of the spring member 33. The housing exposed end of the plunger 47 may include a suitable button formation 49. The opposite end of the'plunger 41 is slotted as at and a pin 5|, or the like, suitably pivotally connects the opposite end of the lever member 35 thereto and it is seated in said slot 50.

When the head 49 is depressed or caused to move toward the body portion I4, the lever 35 is tilted in opposition to spring 38 and the plunger'43 is caused to be retracted in the opening 42 in the housing [3 until it is nested, as it were, in said opening sufficiently so that no portion of the plunger 43 projects outwardly in juxtaposition to the reversing ring structure for operation and control thereof.

The reversing ring structure generally is similar to that disclosed in the before mentioned patents. Herein the same will be set forth in considerable detail because of major differences. The reversing ring structure includes a bottom plate 52, this being shown clearly in Figs. 3, 4 and 5, and being the plate closest to the housing l3, see also Fig. 5. The outer plate is indicated by the numeral 53. This is maintained in spaced relation to the other plate in the manner illustrated herein and as also illustrated in the two before mentioned patents. The parallel plate ring structure is retained upon the axial portion of the housing by means of a locking'ring' 54 seating in the groove in the collar portion 55 of the housing which collar portion also serves as an elongated bearing for a portion of the shaft |2 in substantially the same manner as illustrated in Fig. of Patent No. 1,862,331 and Fig. 1 of Patent No. 1,937,331.

Herein projecting outwardly from the face of the housing I3 are the two anchor members or short posts 56 and 51, the latter being the uppermost-see Figs. 3 and 4. These may serve as ring stops. Each of the pawls 23 which engage the sprocket, as stated, is mounted on a shaft 24see Figs. 2, 3, and 4. The lowermost shaft 24 is provided with a projecting pin portion 58, and the uppermost with a projecting pin portion 59. These two pin portions project into the annular channel formed by the two plates of the reversing ring structure. This structure also includes plate spacing members 69 and 6|, respectively, see Fig. 3, the former being operatively associated with the arm portion 58 and the latter being operatively associated with the arm portion 59 carried by the shafts 24. Each shaft, as before stated, is tiltable, in opposition to the constraint imposed by the respective spring 25, see Fig. 2, in load elevation movement by the ratcheting of the sprocket with reference to said pawls.

A spring 62 is connected at one end to the stationary post 5'|--see Figs. 3 and 4-and at its opposite end is connected to a plate spacer and connecting member 63. A spring 64 is connected to the stationary post 56 and at its opposite end is connected as at 65 to the reversing ring structure and the upper plate 53 thereof. A spring 66 is connected at one end to the arm portion 58 of the lower shaft 24 and at its opposite end is connected to the anchorage 6! carried by an ear 68 radially projecting outwardly from the lower reversing ring plate.

A spring 69 is connected at one end to the arm portion 59 and at its opposite end is connected to a plate spacing and connecting member 10, the lower end of the latter being carried by an ear portion 1| on the lower plate 52. This ear portion provides a shoulder portion 12. The lower plate is suitably relieved as at 13. The upper plate is relieved as at 14 and is also provided with two shoulders and 16 which are in diametrical relation.

Plunger 43 shown clearly in Figs. 1 and 5, is shown in full lines in Fig. 3 and in dotted lines in Fig. 4 and is indicated by the same numeral. The pin portion ll-see Fig, 2-is rigid with and movable by the load elevating pawl 8. This pin portion is that which is operatively associated with the reversing ring and operates broadly in the same manner with said ring as is disclosed in the two before mentioned patents.

In the present invention, pin 11 on handle pawl 8 engages shoulder I5 or shoulder 16, depending upon which side of the hoist the handle is mounted. In this form of the invention the handle 6 has limited rotational or arcuate move ment, to-wit, between portions [8a and lb at each side of the hoist.

The springs 62, 64, 66 and '69see Figs. 3 and 4 -normally constrain the ring structure counterclockwise when the ring structure is locked in load elevating position, so that lower plate portion 13a normally covers the end of plunger 43 for step-by-step lowering, and the structure is held against further rotation when the shoulder 13b on portion 13a engages stop 5'|see Fig. 4.

gWhen the "ring structure is in the load lowering position only-springs '62 and 64 are effective and iconstrain, the ring structure to counterclockwise rotation. Note that springs 66 and 69 in'Fig. 4 are collapsed, but springs 25, attached to pawls 23, oppose springs 62 and 64. The four springs 25, 66 and'69 .in load elevation constitute a dual safety feature.

When these springs are extended by the ring structure being moved clockwise a sufficient angular distance so that shoulder 13b uncovers or clears plunger 43, the plunger 43-see Figs. 3 and.5under the influence of spring 38 forces the plunger to seat behind the shoulder 13b and reverse rotationof the ring due to springs 62, 64, 66' and 69 is prevented until such time as button 49 is depressed to withdraw plunger 43 from the shoulder engagement mentioned. The ring structure then may oscillate without being locked by the plunger and through a range slightly less than that of the arc between shoulders 12 and 13b on the plate 52 of the ring structure.

It will be remembered that each of the sprocket engaging load holding pawls 23 is constrained by spring 25 into sprocket engagement, and arm 58 movable with lower pawl 23 and arm 59 movable with upper pawl 23 are connected to the reverse. ring structure by springs 66 and 69, respectively. Also the ring included spacing portions 60 and 6| are arranged for contact with the arms 58 and 59 and when the ring is moved counterclockwise-see Figs. 3 and 4-the members 60 and 6| will move both pawls 23 into non-sprocket engaging position. This conditions the hoist for free-chain operation providing the handlepawl is held out of ratchet engagement, by member 1 or by plunger IT, as previously described.

Free-chain operation, however, cannot be efiected if there be a load on the chain due to the draft position of ratchet l6 to pawl 8 or sprocket H to pawls 23 because pawl 8 cannot be released under load by either member or member l1, thus preventing accidental dropping of the load should it accidentally be attempted to obtain free-chain condition while under load.

The plunger 43 is normally engaging the stop face 13b when the handle is conditioned for load elevation. In this movement, as previously set forth, the handle carried pawl 8 engages the ratchet and rotates the sprocket with the load chain thereon so that the load is elevated, the load holding pawls 23 alternately ratcheting with respect to the sprocket teeth.

When it is desired to lower the. load step-bystep, the button 49 is pressed inwardly toward the hoist body which releases the pin 43 from engagement with the shoulder 13b of the reverse ring. This permits the pins 6| and 66 to make contact with the arms 58 and 59 rigid with the control pawls 23. If the handle 6 is then moved counterclockwise, the pawl 8 carried by the handle will engage the ratchet I 6, thereby insuring the load is now taken by the handle. Springs 62, 64, 66 and 69 then pull the reverse ring counterclockwise and at the same time lift the pawls 23 out of locking engagement with the sprocket II.

In raising the handle 6 with the load on the pawl 8, the pin 11 comes into contact either with the shoulder 15 or 16 depending upon which side of the hoist body the handle is positioned, thereby returning the reverse ring and disengaging the pins 6|] and 6| from the pins 58 and 59,-

thereby causing one of the pawls'. 23' to. engage the sprocket II and take the load.

After one of the pawls'23 has taken'the load, lifting the handle 6 clockwise'a short distance will result in the reverse ring springs! 62-, -64, 66 and 69 pulling the reverse ringcounterclockwise, the shoulder 15 or 16, respectively, being in contact with the pin 1.! lifting the end of the pawl 8 out of engagement with the ratchet 16. The direction of movement of the handle is then reversed. The reverse ring carries pawl 8 into disengaged position until the end of pawl 8 has passed the point of contact of ratchet [6, then the shoulder 15 or 16 is disengaged from the pinll permitting the pawl 8 to reengage in the next consecutive ratchet tooth. This action is repeated until the load is lowered to the desired position.

When the handle is moved to that position, carrying with it the reversing ring structure, until the plunger 43 is uncovered, it immediately seats behind the shoulder 13b and holds the reversing ring structure in the load elevatingand holding position and in that position, the sprocket engaging pawls 23 are constrained to load holding action.

This form of the invention has this safety feature which is not disclosed in the two before mentioned patents and which the same are incapable of attaining. This feature is that if the handle while carrying the load should be inadvertently released by the operator, in the present instance the load will only lower the equivalent of one sprocket tooth for the following reason: The momentum imparted to the handle when it is thus accidentally released in the two before mentioned patents may insure that the handle oscillates to and fro and which will gradually pump off to the extent the load will be rapidly lowered and thus be detrimental to any object positioned beneath the load and to any workman working underneath the invention. The present invention prevents this pumping off for the following reason:

If the handle escapes from the operator while lowering the load, as before mentioned, the handle will make a complete oscillation and in so doing it will, at theextreme point of stroke move the plate portion 13a into such position that the plunger 43 is uncovered and thereupon due to the spring 38, the plunger 43 immediately is projected into the path of said plate portion (3a. and engages the shoulder 13b thereon and locks the reversing ring in the load elevating and holding position and when thus positioned, the handle cannot oscillate to and fro except under enough power applied to the handle to lift the load and not through power applied by the load. In other words, extreme handle movement has automatically conditioned the hoist into lifting position instead of reversing load lowering position.

The main features of this invention, therefore, relate to the notched character of the handle carried pawl 8 for nesting a ratchet tooth because in the present form of the invention the number and size of the teeth of the ratchet are materially reduced with reference to the load. The draft feature with respect to the pawl mentioned in the two before mentioned patents, is also retained in the present invention.

The second novel feature consists in providing, as herein illustrated, the ratchet with a number of teeth twice that of the sprocket.

Since this is a chain hoist and since the load factor or capacity of the hoist is determined by the chain, it1wi1l be obvious thata minimum size of. chain can be employed for a predetermined load and this size of chain determines to a considerable degree the size of the teeth of the sprocket that meshes therewith.

Accordingly, in order to keep the size .of the hoist down to a minimum and keep the size of the teeth incident to the load requirements to a maximum, the present inventionby the incorporation of two 'angularly offset sprocket engaging pawls 23 permits a. smaller sizehoist to accommodate the load for which it is designed and permits the handle to operate through a range-of approximately half'that normally required by each of the before mentionedpatents in order to effectively operate said hoist for elevating. or low ering. This, as previously stated, permits a hoist of substantially the same character but embodying thesefeatures to be utilized in such locations where minimum area is available for handle oscillation or operation.

Another feature incident to the automatic locking feature or a corollary'thereof is as fol-' lows: Upon movement of' the handle to the extreme position described, the structure will automatically be reconditioned for load elevation. The only manual operation, therefore,.required in this hoist for reversing ring conditioning is the depression of the button 49 for load lowering only and in all other respects thehoist is full auto matic; I

While the invention has been illustrated and described in great detail inthe drawings and foregoing description, the same is to be considered as illustrative and not restrictive in character.

The several modifications described herein as well as others which will readily suggest themselves to persons skilled in this art, all are considered to be within the broad scope of the invention, reference being hadto" the-appended claims.

Th invention claimed is:

1. In a hoist of the character described, the combination of an oscillatable reversing ring structure having a stop portion, a catchnormally constrained toward stop engagement, and manually operable means for moving said catch from said stop engagement in opposition to its constraint-to permit ring oscillation, said ring having a portion arranged to preventcatch-stop engagement for limited oscillation of the ringbut permitting such engagement 'upon extreme os, cillation of the ring.

' 2. In a handle operable hoist'having an oscillator-y operating handle, an elongated load sustaining means, a member rotatable by the handle and engaged with said elongated load sustaining means for load movement in accordance with member movement, means carried-by the handle for operativ connection with the-member for load movement in one direction of handle movement, other means arranged for operative connection with the member forload holding in reverse movement of the handle, said last two mentioned means being alternately associated in operative relation with said member upon oscillation of the handle, the combination of' a reversing structure movable with and by the handle and when in load elevationcondition position permitting load elevation'and preventing load lowering and when in load lowering condi' tion position permitting load lowering and-preventing load elevation, catch means for said-reversing structure normally constrained for asmovement of the handle beyond a predetermined handle position and following the manual actuation of the catch means, to prevent further load lowering movement of the load sustaining means, movement of the handle short of the aforesaid predetermined position of the handle securing 5 continued load lowering.

FREDRICK W. COFFING.

Images