US2519400A

US2519400A - Ratchet structure

Info

Publication number: US2519400A
Application number: US709506A
Authority: US
Inventors: Erford E Robins; Humphrey F Parker
Original assignee: COLUMBUS MCKINNO CHAIN CORP
Current assignee: COLUMBUS MCKINNO CHAIN Corp
Priority date: 1946-11-13
Filing date: 1946-11-13
Publication date: 1950-08-22
Anticipated expiration: 1967-08-22

Description

Aug. 22, 1950 E. E. ROBINS ETAL I 2,519,400

RATCHET STRUCTURE Filed Nov. 13, 1946 I 4 Sheets-Sheet 2 INVENT frfard f. Rob/77s an Bjum a/rrg f Fir/Ker @w, @wl w A TTOR/VEYS Aug. 22, 1950 E. E. ROBINS EI'AL RATCHET STRUCTURE sf. 5 w 4 M w N e. 6 TWO N m 2 6 a W 1 m T s WEE! T a a A a 4 m Filed Nov. 15, 1946 1950 E. E. ROBINS ETAL 2,519,400

RATCHET STRUCTURE Filed Nov. 13, 1946 4 Sheets-Sheet 4 INVENTORS E/ford E. Rob/n5 and Hum 0hr ff Par/(er BY ATTORNEYS Patented Aug. 22, 1950 phrfey F. Pal-ken- Buffalo; N. Y., assignors to ColnmbusMcK-innon Chain Corporation, Tonawanda, N. Y.

Application November13, 1946', SerialNo. 709,506

ie-Claims.

1 This invention relates to lever-operated or so c'alled ratchet hoists and pullers, such as are manually operated for raising and lowering? loads, or for tensionin wires or cables; or applying pulling loads in any industry; I

Specifically, the invention relates to improvements in the general type of hoist or puller suchas is shown in U; S; Patent No;v 23243361; andi wherein it is arranged that whenever the load is not being taken directly by the operating lever the load is sustained by the frame of the de-' vice independently of the operating lever by reason of automatic operation of friction brake means.

One of the objects of the present invention is to provide in a hoist or puller of the character described, an improved friction brake actuating cam arrangement. Another object of the invention is to provide a hoist or puller of the character described which embodies structural features enabling the deviceto be designed into more compact and space-saving form. An other object of the invention is to provide in hoists or pullers of the character described an improved method of relative assembly of the operating portions. Another object of the invention is to provide in a hoist of the character described an improved bearing arrangement for operative parts thereof. I

Other objects'ofthe invention will appear from the specification hereinafter.

In thedrawing Fig. l is a sectional view through a hoist or puller of the invention;

Fig. 2 is a section taken along line 11-11 of Fig; 1;

Fig; 3 is a section taken along lineIIP-JII of Fig. 1;

Fig. 4 is an enlarged fragmentary view of the brake actuating cam portion of the unit;

Fig. 5 is a disassembled view of the brake ratchet hub and wheel portion of the' device; and

Fig. 6 is a perspective of the brake actuating cam thereof.

In the drawings the hoist or puller of the invention is illustrated to comprise a frame 1 Eimounting a support hook l2 by means of a washer and nut connection device M, as is conventional in thehoist art. The frame I 9 carries bearings -18 in which are journalled the hoist load lift wheel shaft. This shaft includes a reduced? portion 2c disposed within the bearing [6; an

enlarged" portion 22 disposed within the larger diameter bearing I8; a lift'whee1portion24; a face plate portion 26;. and an opposite reduced end portion 28; The. bearing I6 is'set against a:

shoulder 29' of the frame structure to transmit end thrust loads thereagain'st; and thus the liftwheel; 24 transmits end thrust loads directed" toward'. the: left as viewed in Fig; 1 to the bearing. I56. The shaft and bearingreceiving opening portions'. of the frame iii are so dimensioned that the bearing and shaft elements may be progres-- sive'ly assembled upon the frame by slip-fittingv the parts: into the frame from right to left asviewed in Fig;v 1.

The extreme left end portion of the shaft 2d is grooved as indicated at 30, and a U-shaped bracket-i62 isbol't'ed to the frame as by m'eansof astu'd" 3t; one end of'the bracket 32" beingthere by disposed within the groove portion-3ilf of the shaft to prevent accidental disassembly of the shaft from the frame. The other end of the bracket 32 turns upwardly into the centrally grooved portion of the lift wheel element 2 F tofunction as a chain stripper, as is well known in the hoist art.

A friction disc 35 is rotatably mounted upon the shaft end portion 28 next adjacent to the face plate portion 2%. A ratchet wheel 49 is rotatabl'y mounted upon the shaft portion 38 by means of a Wearresistant bushing 42', and a second friction disc 44 is rotatably mounted upon the shaft portion 28' next adjacent to the ratchet wheel 40. A. lever ratchet hub is rotatably mounted upon the shaft portion 28 and carriestherewith a ratchet Wheel portion 48 which is externally toothed as indicated at 50. The ratchet hubit has formed integrally therewitha pair of helically shaped surfaces 52-54, and a brakeearn- 56 having similarly helically shaped surfaces 58-55 is mounted adjacent the outer end of the shaft portion 28 and keyed thereto as at 50. The cam surfaces 52545859 are arranged so that the hub and cam members 48- 56 are complementary'at the surfaces of contact therebetween; and whereby relative rotational movements therebctween will force the ratchet hub 46 to be displaced axially relative to the cam 56;. The brakev am 56 is axially positioned and locked against movement toward" theright as viewedin Fig. lrelative tothe shaft-2E by means of. athreadedlnut. 621 and cotter pin-.64. A cover. platefili isv bolted by means of screws 68-68 to. the lever ratchet-member it so asto'enclose the mechanism subsequent tov assembly thereof. A second cover plate 51 is press-fitted into the op--- posite: end of the housing to enclose the-latter.

The lever ratchet hub and. ratchet Wheel? unit 46:--48 is encircled by anannular wear-resistant bushing 69 about which is cast the hub portion of the hoist operating lever 18; and as illustrated in Fig. 2, the lever 10 carries a plunger 12 which is normally biased by means of a compression spring 14 so as to move at its toothed end portion 16 into meshed engagement with the ratchet wheel 48. The tooth portion 18 of the plunger 12 is so shaped as to cooperate with the ratchet wheel 48 to block relative movement of the lever 10 and the ratchet wheel 48 in one direction, while permitting the ratchet wheel 40 to cam the plunger 12 out of blocking position for rotation of the lever 18 in the opposite direction. However, the plunger 12 is arranged to be manually reversible in attitude, and for this purpose is provided with a laterally bent finger 88 whereby the operator may withdraw the pawl and rotate the finger 88 through 180, and then upon release of the pawl it will reengage the wheel 48 so as to block movement of the lever relative to the ratchet wheel in the opposite direction. The lever frame 10 is recessed as indicated at 82 and the finger portion 89 is formed with a boss 84, whereby whenever the plunger 12 is in springbiased position the recess and boss formation 82-84 cooperate to lock the lever against rotation. However, the finger 80 may be manually retracted against the action of the spring 14 and then only partially rotated so as to cause the boss portion 84 to ride upon the outer shoulder of the recessed portion 82, to hold the pawl out of engagement.

The frame 10 carries a boss portion 86 extending radially therefrom (Figs. 2-3); the portion 86 being radially bored to receive in slip-fitted relation a cylindrical shaped pawl member 88. The outer end of the pawl 88 is shaped with a finger portion 90 for convenient gripping by the operator. The pawl portion 98 is transversely slotted as indicated at 92 and is centrally bored as indicated at 94 to accommodate therein a compression spring 95 bearing at its inner end against the inner closed end portion of the pawl 88. Subsequent to mounting of the spring 95 within the pawl cylinder, a pin 96 is slip-fitted through registering openings in the body portion 86 so as to bridge the bored portion of the pawl 88 and to provide an anchor for the outer end of the spring 95. Thus, the spring is arranged to resist withdrawal of the pawl 88 from engagement with the ratchet wheel 40. The body portion 86 is formed with a pair of outstanding abutments 98-98 over which the slotted portion 92 of the pawl head 90 slip-fits in one position of the pawl cylinder; but upon manual withdrawal of the pawl from engagement with the wheel 48 the pawl member may be twisted so that the enlarged head 98 rests upon the outer ends of the abutments 98-98, whereby the pawl is withheld from engagement.

The operation of the hoist or puller of the invention may be described as follows: Preliminary to hoisting or pulling against a load the hoist device is hung by means of the hook l2 upon some stationary anchor means at such position that it will be convenient to manipulate the lever 18 with oscillatory motions, and with the load chain 99 extending therefrom into connection with the load. It is then usually desirable to take the slack out of the load chain prior to levering the handle 10, and this is accomplished by withdrawing the ratchet control elements 80-90 from engagement with their respective ratchet wheels, and rotating them slightly so that they rest upon the adjacent abutments so as to be held out of engagement with their ratchets. This permits the operating shaft 28 to be freely rotated so that the free end of the load chain may be simply pulled upon to rotate the load lift wheel unit of the mechanism and to take any slack out of the load carrying portion of the chain. The ratchet devices -98 are then turned and permitted to return to engagement with their respective ratchet wheels; the finger 80 being turned, of course, so that the pawl 16 will be rotated in the proper direction to cause raising or pulling of the load when the lever 10 is oscillated. Thus, oscillation of the handle 18 will cause the ratchet wheel 48 to rotate along with the brake hub portion 46. As the portion 46 rotates the helically formed surfaces of the members 46-56 will cause the hub 46, together with the ratchet wheel 40 and the friction discs 38-44 to be forced endwise toward the left as viewed in Fig. 1 and into mutually pressure bearing relation against the face plate portion 26. This will cause the friction surfaces to become engaged so as to force the load lift wheel portion 24 of the shaft to rotate along with the lever 10; and the friction between the brake elements will be sufficient to sustain the load when the operating handle 10 is being moved backwardly intermittently of each pulling stroke thereof. Thus, the handle 10 is simply oscillated back and forth until the load has been moved to the desired position, while at all times the load is frictionally sustained because of the fact that the ratchet pawl 88 is in engagement with the teeth of the wheel 48, thereby preventing its movement backwardly when the load is not being sustained by the operating handle during backward movements thereof.

When it is desired to lower or to relax the pull upon the load, the ratchet pawl control finger 80' is withdrawn outwardly against the tension of the spring 14, and when the hub portion 84 has cleared the recess 82 the lever 80 is rotated through and then allowed to return again under the action of the spring into pawl-meshing position. Thus, the pawl 78 will be in engagement with the wheel 48, but in reverse attitude. Oscillation of the handle 18 will now serve to operate the shaft 28 in the reverse direction and against the friction produced by the brake elements. The first movement of the handle under these conditions will serve to loosen the frictional engagement of the brake surfaces sufficiently to permit the operator to re lax the pull upon the load. Since the lowering of the load will, however, tend to turn the shaft 28 and thereby rotate the brakecam 56, the load itself will keep the frictional surfaces of the brake unit in engagement sufficiently to sustain the load. Thus, under these conditions the load is never carried by the handle but always by the brake unit, so that there is no tendency at any time for the handle to escape the grip of the operator and run wild. However, as an extra safety precaution, we prefer to form a handle stop abutment I00 extending from the upper portion of the frame I0 into registry with a boss portion I02 (Fig. 1) of the lever 10, so that the latter is prevent from rotating more than 360 under any condition of loss of control of the handle by the operator. This further minimizes the opportunities for accident. The boss I02 is relatively narrow when viewed in side elevation (Fig. 2) and is located centrally of the lever 10, whereby the lever 10 will have a permissible range of travel through substantially 360, in-

stead of a substantially lesser range of travel as would be the case in event the stop-portion I were arranged to abut against a side Wall portion of the lever 10. It will be understood that the handle need not be oscillated through any prescribed degree of angular displacement to operate the device so long as successive teeth of the ratchet wheel 48' are engaged, and that it may be oscillated within any convenient segment of the permissible 360 range of movement.

As illustrated more particularly in Fig. 5, a special feature of the invention is found in the mode of fabrication of the ratchet hub and wheel unit 46-48. In order to attain adequate tooth strength in the wheel portion 48, it is highly desirable to provide the member 48 and the toothed portions 50 thereon to be machined from solid hard metal stock such as steel. It would be rather difficult as Well as very expensive, however, to similarly form the hub and cam surface portions 46-52-54 as an integral part of the member 48. Therefore, the present invention contemplates formation of a key shaped annular flange H0 at one end of the wheel member 48, and subsequent die casting suitable metal material into keyed relation upon the flange H0 so as to form the hub and cam elements 46-52-54 integrally with the gear wheel member 48. Thus, the die cast portion 46 will be locked upon the wheel portion 48 by the flange I In so as to resist axial separation of the parts. Preferably, the flange portion I I0 is cut away at intervals therealong, as indicated at H2 so that when the material of the member 46 is die cast into connection with the wheel member 48, some of the die cast material will fill the spaces I12 so as to provide keying abutments I I4 filling the spaces H2 of the wheel, thereby locking the hub 46 and the wheel 48 against relative rotation. In this manner the cam surfaces 52-54 of the hub member 46 are readily formed without difiiculty and relatively inexpensively, while the toothed ratchet wheel portion of the unit is provided of hard steel, for maximum service.

Thus, it will be appreciated that the invention provides an improved hoist or puller mechanism wherein the brake ratchet hub and wheel elements 46-48 are fabricated and relatively assembled in improved manner. Also, the arrangement of the cam member 56 so as to be telescopically recessed within the brake ratchet hub unit 46-48 provides a brake actuating mechanism of extreme ruggedness in combination with a substantial reduction in the overall length of the brake and brake cam mechanism. This enables the overall design of the unit to be of reduced dimensions, which is an important advantage in this art.

The provision of the paired bearings I6-I8 of different diameters in the frame I0 provides a straddling support for the load lift wheel 24 while at the same time facilitating assembly of the mechanism by permitting the operating unit to be slip-fitted into the frame from one end thereof and then retained against accidental disassembly by the retainer 32. This combination stripper and lift wheel shaft retainer 32 provides a simple and effective device performing a double function and thereby provides a further advantage over previous designs; and the stop device I00 provides a simple yet effective arrangement for increasing the factor of safety in operation of devices of this character. The steel bushing 69 bears upon the ratchet hub 46 and upon the ratchet wheel 48 at opposite sides of the ratchet teeth 50, and the latter are retracted to prevent them from scoring the hub of the lever 10. Thus, a durable two-part bearing for the lever upon the brake unit is so provided as to remain stable and snug yet non-binding over long periods of service. The bushing 69 is knurled as at H5 so that when the handle 10 is die-cast thereon a keyed bonding of the two parts is effected.

It will be understood that although only one form of the invention has been shown and described in detail, it will be apparent to those skilled in the art that the invention is not so limited but that various changes may be made therein without departing from the spirit of the invention or the scope of the appended claims.

We claim:

1. In a ratchet puller, a two-piece ratchet wheel comprising a die-cast, cam-faced hub member and a machined steel ratchet ring, said ratchet ring having been preformed with a key-shaped flange for overlapped connection with said diecast member, said flange having key slots extending thereinto, and said die-cast member having been cast upon said ring member so as to be formed integrally therewith in keyed relation upon said flange.

2. In a ratchet puller, a two-piece ratchet wheel comprising a die-cast, cam-faced hub member and a machined steel ratchet ring, said ratchet ring being of cylindrical shape and having been preformed with a key-shaped flange at one end for overlapped connection with said die-cast member, said flange having key slots extending thereinto, and said die-cast member having been cast upon said ring member so as to be formed integrally therewith in keyed relation upon said flange with the cam-faced portion thereof telescopically positioned within said ratchet ring.

3. In a ratchet puller, a two-piece ratchet wheel comprising a cast cam-faced hub'member and a machine steel ratchet ring, said ratchet ring having been preformed with a flange for overlapped connection with said cast member, and said cast hub member having been cast upon said ring member so as to be formed integrally therewith in keyed relation upon said flange.

4. In a ratchet puller, a two-piece ratchet wheel comprising a cam-faced cast hub member and a wear-resistant metal ratchet ring, said ratchet ring having been preformed with flange for overlapped connection with said cast member, and said cast hub member having been cast upon said ring member so as to be formed integrally therewith in keyed relation upon said flange.

ERFORD E. ROBINS. HUMPHREY F. PARKER.

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

UNITED STATES PATENTS Number Name Date 170,917 Thomas Dec. 7, 1875 611,084 Strom Sept. 20, 1898 1,012,176 Stewart Dec. 19, 1911 1,300,232 Skandora Apr. 8, 1919 1,402,898 Schwerin Jan. 10, 1922 2,126,843 Tintera et al Aug. 16, 1938 2,243,361 Stahl May 27, 1941 2,343,884 Cofling Mar. 14, 1944