US3547407A - Multiposition direct drive hoist - Google Patents

Description

United States Patent Inventor Ralph A. Ratclifi 1300 Sunnyslope Ave. P. 0. Box 543, Belmont, Calif. 94002 Appl. No. 764,537

Filed Oct. 2, 1968 Patented Dec. 15, 1970 MULTIPOSITION DIRECT DRIVE HOIST 11 Claims, 5 Drawing Figs.

74/543, 74/548 Int. Cl 866d l/00 Field of Search 254/186,

I67, 251(HC), 163, 164:74/543, 548; 287/53(H) [56] References Cited UNITED STATES PATENTS 1,189,606 7/1916 Miller 74/548 2,967,046 ill 96] Ratcliff 254/167 FOREIGN PATENTS 396;028 3/1909 France 245/186HC 629,236 4/1936 Germany 74/548 Primary ExaminerHarvey C. Hornsby AnomeyFlehr, Hohbach, Test, Albritton & Herbert ABSTRACT: A hoist for supporting a load on a chain engaged with a sheave on a rotatable shaft within a casing. Direct drive operating handle structure is operatively supported directly on the sheave shaft by a handle boss engaged with the operating mechanism of the hoist. The boss is pivotally received within a chamber in'the sheave shaft end within the casing and is engaged with the operating mechanism via a ratchet plate having a multipoint internal star recess compatible witha polygonal projection on the boss.

PATENTED DEC] 5 I976 SHEET 1 BF 2 INVENTOR. 847mm:

flwwiri IJ my PATENTED DEC] 5 I970 SHEET 2 [IF 2 INVENTOR. Fit/9H 4 @4717; m";

MULTIPOSITION DIRECT DRIVE HOIST BACKGROUND OF THE INVENTION 1. Field of the Invention This invention relates generally to the field of load bearing devices. In its preferred form, the invention is embodied in a chain-type hoist although its utility is not restricted to such devices. This invention has particular .utility when incorporated into a pawl-and-ratchet-type hoist although its utility also is not restricted to that specific type of construction.

More particularly, this invention resides in an. improved operating handle structure for a hoist which produces important advantages of simplicity, compactness, lighter weight and less side draft when compared with operating handle structures heretofore known or used in the load bearing art. Such advantages'are obtained by mounting the operating handle in direct engagement with the chain sheave shaft of the hoist within the hoist casing. Still more particularly, this invention relates to a direct drive hoist employing a handle structure which is directly rotatably mounted within a chamber fonned in an end of the chain sheave shaft and which is operatively engageable with the hoist operating mechanism in a multiplicity of positions in excess of two. i

2. Description of the Prior Art Much prior'art exists'in the field of load bearing devices, both of the pawl-and-ratchet-type and of the friction brake type. Exemplary of such prior art are. the devices shown in Ratcliff U.S. Pat. No. 2,967,046, dated Jan. 3, 1961, and U.S. Pat. No. 3,245,660, dated Apr. 12, I966, which illustrate pawl-and-ratchet ratchet and friction-brake-type hoists, respectively. However, the hoists of such exemplary patents, and other prior art devices so far as is known, neither disclose nor suggest the improved operating handle structure of the present invention. That is, prior-art patents and commercial devices available on the market, so faras is known; have not incorporated therein an operating handle structure of the type disclosed herein which is pivoted on and directly engaged with the chain sheave shaft of a hoist within the confines of the casing of such hoist. E

While it has been generally known'heretofore to provide structure by means of which an operating handle may be operatively connected with the operating mechanism of a hoist in a multiplicity of positions (as disclosed in Ratcliff U.S. Pat. No. 2,967,046), such an improved feature has not been incorporated into a simplified direct drive hoist of the type disclosed herein. The hoist of U.S. Pat. No. 2,967,046 to Ratcliff, incorporates therein a cam type operating mechanism which is designed to produce a substantial mechanical advantage upon actuation of the operating handle. With the present invention, no intermediate cam or other type mechanical advantage producing mechanism is employed, mechanical advantage being produced with the present invention by the length of the operating handle employed.

Also, while it has been generally known heretofore to provide a drive recess in the end of a drive shaft of a friction brake hoist, as disclosed generally, for example, in Harrington U.S. Pat. No. 2,894,610, dated July 14, i959, such recess has been designed to receive therein a separable operating wrench, the accommodation of which necessitates an extension of the drive shaft which projects beyond the hoist casing and thereby produces an undesirable projection which adds to the bulkiness of the hoist and detracts from its appearance. Such a coristruction furthermore does not produce the other important advantages of the subject invention noted herein. Ah arrangement such as disclosed in the Harrington patent furtheris uhdesirable in that the projecting shaft end provided to accommodate the recess and drive wrench results in substantial side draft (lateral canting of the hoist during operating thereof) when the hoist is operated, particularly when lighter loads are being raised.

So far as is known no loadsustaining device having the particular construction or improved operating advantages characteristic of the improved yet simplified operating handle LII structure disclosed herein has been patented or employed commercially heretofore.

SUMMARY or THE INVENTION The present invention relates generally to load sustaining devices, and more particularly to an improved operating handle structure for such devices. Still more particularly, this invention relates to a multiposition operating handle structure for a chain-type hoist in which the operating handle is pivotally mounted on and directly engaged with an end of the chain sheave shaft over which a load supporting chain passes. To that end, a pivot chamber is formed directly in an end of the chain sheave shaft and a boss formed on the operating handle of the hoist is pivotally received in such chamber. The handle is maintained operatively connected with the sheave shaft by means of a pin which projects from the shaft chamber through a bore formed in the handle boss. Suitable securing means is provided to preclude inadvertent separation of the handle from the pin.

The handle boss in turn is operatively and nonrotatably connected with a portion of the operating mechanism of the hoist so that, upon oscillation of the handle, the operating mechanism is actuated to effect rotation of the chain sheave sh'aft in a predetermined direction to effect raising (tightening) or lowering (loosening) of a load engaged with the chain.

hoists and other load bearing devices which employ an operat- 1 ing handle structure to rotate a shaft or the like; the term "chain used herein is intended to include various types of load sustaining elements, such as coil chain, rolleror rollerless chain, and other load sustaining elements, such as cables or ropes; the term sheave used herein is intended to include wheel structures having teeth or depressions thereon for engagement with the links of chains, as well as drums or grooved pulleys for engagement by cables or'likeload sustaining elements.

From the foregoing, it should be understood that objects of this invention include: the provision-of improved operating handle structure for a hoist; the provision of operating handle structure for a hoist which is directly engageable with a chain sheave shaft to provide a compact, simple and light weight construction which produces minimum side draft during actuation of the handle; the provision of a'hoist handle structure which is operatively mounted by a chamber formed in an end of the chain sheave shaft in which a portion of a handle boss is directly receivable within the confines of the hoist casing; the

DESCRIPTION OF THE DRAWINGS FIG. 1 is a side elevational view of a hoist embodying the improved operating handle structure of this invention.

FIG. 2 is an exploded isometric view of the handle structure, operating mechanism, and control structure of the hoist shown in FIG. 1.

FIG. 3 is a front elevational view of the operating handle of the hoist taken in the plane of line 3-3 of FIG. 2.

.parts in the patented hoist.

FIG. 4 is an sectional view through the hoist illustrating the assembled operating handle structure and showing its operative relationshipto the chain sheave shaft and the operating mechanismof the hoist.

FIG. Sis a vertical sectional view through the hoist taken in the plane of line of FIG. 4 which illustrates the operative interconnection between the handle and the operating mechanism.

DESCRIPTION OF THE PREFERRED EMBODIMENT As noted previously, the present invention may be incor- I porated in load bearing or load sustaining devices. particularly hoists, of various constructions. The preferred embodiment il- In that connection, for a detailed understanding of the operation and function of the operating mechanism and control structure illustrated in the attached drawings, reference is directed to the disclosure in such patent. It should be noted that the exemplary hoist shown in FIG. 1 herein corresponds substantially to the patented hoist construction with only those modifications having been made which are necessary to incorporate thereinto the improved operating handle structure of this invention.

In the embodiment illustrated in the exploded view of FIG. 2, the hoist construction shown has been divided broadly into three subassemblies which are mountable in or on a two-piece separable hoist casing. Such assemblies include: (A) the improved operating handle structuresupported by the casing;

.(B) the operating mechanism positioned within the casing which is effective to produce raising or lowering of a load in a predetermined controlled manner; and (C) the control structure positioned within and mounted on the casing for regulating operation of the operating mechanism. The control structure and operating mechanism together provide means for regulating and controlling rotation of the chain sheave shaft of the hoist in a manner to be described.

The configuration and compact construction of an assembled hoist is shown in FIG. 1. The hoist casing is comprised of two parts, a main casing section 1 and a removable casing cap section 2 which is securable to the main casing section by a plurality of cap screws 3 receivable in threaded bores 4 provided in an end face 5 of the main casing section 1. The casing cap section is provided with apertures 6 to receive the cap screws therethrough. As seen in FIGS. 2 and 4, cap section 2 comprises a generally flat plate which contacts the end face 5 .of the main casing section and encloses the internal operating and control components therein.

Details of the improved operating handle structure of this invention are set out hereinafter. Preliminarily, however, a brief description of the operating mechanism and control structure of the exemplary hoist shown will be described.

OPERATING MECHANISM AND RELATED STRUCTURE The operating mechanism illustrated is of the pawl-andratchet-type which permits raising or lowering of a load in step-by-step fashion in the manner described in U.S. Pat. No. 2,967,046 to Ratcliff.

As shown in FIG. 4, shaft 7 is rotatably mounted in casing section 1 in a stepped through bore 11 in which bearing ring embers 12 and 13 are positioned. The shaft includes a cylindrical bearing section 14 at one end thereof and an enlarged cylindrical bearing section 16 intermediate its ends which are rotatably engaged in the bearing rings 12 and 13 respectively. Shaft 7 isslidable longitudinally of the casing bore '11 so that chain sheave 9 may be positioned in alignment with a hollow sheave receiving portion 17 in the casing section I.

It is through such hollow casing portion 17 that a chain 18 is movable. Opposite reaches of the chain pass through openings 19 provided therefor in the bottom of the casing in know fashion. The chain passes over and is engaged with sheave 9 so that upon rotation of the sheave in a predetermined direction, a load supported upon a hook 20 secured to the end of one reach of the chain may be raised (tightened) or lowered (loosened) asdirected in accordancewith operation of the operating mechanism regulated by the control structure to be described. A hook member 21 projects from the top of main casing section 1 and is maintained engaged therewith in known fashion so that the hoist may be supported during use.

In the embodiment illustratedin exploded showing of FIG. ll

1, rotation of sheave 9 in a counterclockwise direction will effect load raising (tightening) while rotation of the sheave in a clockwise direction will effect load, lowering (loosening). Rotation of the sheave in one direction or the other is permitted or precluded selectively by pawl means provided for engagement with ratchet wheel 8. Two pawls, a holding pawl 22 and an operating pawl 23, are mounted in the casing in line with the ratchet wheel and are normally urged toward engage ment therewith by springs 24 and 26. Spring 24 is anchored to the casing by a pin 27 (FIG. 5) which extends interiorly thereof while spring 26 is anchored in the manner to be described. Operation ofthe pawls and their selective engagement or disengagement with the teeth'of the ratchet wheel 8 is controlled and regulated by the control structure in the manner described in detail in U.S. Pat. No. 2,967,046 to Ratcliff.

Holding pawl 22 ispivotally mounted on a mounting pin 28 provided interiorly of the casing section 1. Operating pawl 23 is pivotally mounted between a pair of inner and outer ratchet plates Hand 31 which in most general respects correspond in construction and function to the ratchet plates disclosed in the Ratcliff patent but which are modified slightly forpurposes of this invention in the manner to be described. Inner ratchet plate 29 is rotatably mounted on the enlarged bearing section 16 of the sheave shaft for selective rotatable movement about the axis of the shaft. As the present embodiment provides no shaft structure upon'which the outer ratchet plate 31 is supportable; the latter .is operatively connected with the inner ratchet plate so as to be supported thereby.

The two plates thus are operatively interconnected to rotate in unison. In that regard, outer ratchet'plate 31 is provided with a pairof adjacent holes 32 through which a pair of screw fasteners 33 extendwhich are threadedly received in threaded holes 34 provided in the inner ratchet plate 29. To maintain the ratchet plates separated from each other a distance which permits them to straddle the ratchet wheel 8, a spacer block 36 is interposed between the ratchet plates. Spacer 36 is provided with holes 37 therethrough to accommodate the screw fasteners 33. An additional hole 38 is provided-through the spacer block to receive th'erethrough a shoulder pin 39 which in turn has its oppositereduced ends received in openings 41 g and 42 in the inner and outer ratchet plates respectively. The

shoulder pin cooperates with the spacer in maintaining the ratchetplates spa cedly mounted a distance corresponding generally to the transverse dimension of the ratchet wheel 8. It

Such mechanism includes a one-piece chain sheave shaft 7 on which are nonrotatably mounted a ratchet wheel '8 anda chain sheave 9. In the illustrated embodiment, the chain sheave is of the type adapted to receive thereover a coil-type will be understood that upon forced rotation'of outer ratchet plate 31, the inner ratchet plate will rotate therewith.

Operating pawl 23 is pivotally positioned between the ratchet plates by. means of a mounting pin 43 having reduced shoulders, the ends of which are receivedin respectiveholes 44 and 46 in the inner and outer ratchet plates respectively;

The aforementioned. coil spring 26 is anchored to amounting pin 47 projecting from the underside of spacer 36 as seen in FIG. 5.

It should be understood that upon rotation of the ratchet plate 31 in the manner to be described by the improved operatinghandle structure of this invention, operating pawl 23 will be employed to actuate the ratchet wheel in the manner disclosed in U.S. Pat. No. 2,967,046 to Ratcliff. Holding pawl 22 maintains the load when the operating pawl 23 is being repositioned during actuation of the operating-handle structure.

Control Structure Selective engagement or disengagement of the respective pawls is effected by the exemplary control -structure illustrated in FIGS. 2, 4 and 5 which corresponds to the control structure shown and described in US. Pat. No: 2,967,046 to Ratcliff. Such control structure includes a pairof control rings 51 and 52 which are rotatably mounted on the enlarged bearing section 16 of the sheave shaft. Operation of the control stru ture fonns no part of this invention and reference is directed to the U.S. Pat. No. 2,967,046 to Ratcliff for an understanding thereof. However, it should be understood that the position of the respective control rings, and their control affect on the pawls 22'and 23, is regulated by a control lever 53 positioned externally of the casing which is operatively connected with a control shaft 54 which extends through the casing and is con nected therein with a control link 56 which in turn. is operatively connected by a pair of coil springs 57 and 58 which are anchored on pins 55 and 59 projective from the respective control rings. Upon positioning of the control lever 53 in a predetermined position (for Up, Down, or Free Chain control) the control structure-is actuatedto regulate engagement of the operating pawl and holding pawl that up, down or free chain movement of sheave 9 mayv be effected in the manner disclosed in detail in U.S. Pat. No. 2,967,046 to Ratcliff.

improved Operating Handle Structure It will be noted that the operating handle structure of this invention cooperates with the operating mechanism of the hoist illustrated in a different fashion from that disclosed in U.S. Pat. No. 2,967,046 to Ratcliff. With the present invention, the operating handle structure is directly engaged with the chain sheave shaft 7, rather than indirectly engaged therewith through a mechanical advantage cam mechanism as in the Ratcliff patent. It is to permit such direct'engagement, and to effect the advantages produced thereby; that the improved operating handle structure of this invention is provided.

As seen in FIGS; 3 and 4, the operating handle structure includes an operating handle, generally designated 60, defined by a handle body 61 and a graspable extension 62 secured by welding or equivalent means to the lower end of the handle body (FIG. 4). A handle grip 63 preferably is provided at the lower end of the handie extension. g

At its upper end, handle body 61 includes a projecting boss 64 defined by a noncircular projection Y66 and a circular cylindrical extension 67 which extends beyond projection 66. In the preferred embodiment illustrated, projection 66 is polygonal, preferably hexagonal, in cross-sectional configuration as best seen in FIG. 5. Boss 64 further includes a narrow enlarged circular cylindrical bearing section 68 interposed I between projection 66 and the main portion of the handle 3 body. Section 68 is receivable in an opening 69 provided in the casing closure cap plate 2 and provides a bearing shoulder during movement of the handle body relative to the hoist casmg. g

A stepped bore 71 extends through the handleboss and the an elongated channel-shaped recess 73, the purpose of which is to reduce the weight of the handlewithout affecting its strength while at the same time providing a depression for the purpose to be described.

To adapt the operating handle to be directly engaged with the chain sheave shaft, a longitudinally extending axial chamber 76 is formed directly in the end of the shaft on wh'ich ratchet wheel 8 is formed. Such chamber, as best seen in FIG. 4, is generally circular cylindrical in cross section. A threaded axial bore 77 extends further into the shaft from the base of the chamber and in such threaded bore is received an elongated headless mounting pin 78. While pin 78 is provided with a threaded inner end 75 and is threadedly engaged within the sheave shaft in the illustrated embodiment, it should be un derstood that the same could be welded in place if preferred. As seen in H6. 4, pin 78 projects from the chamber beyond the end of the sheave shaft so that its outer end 79 is positioned within recess 73 of the handle body.

When the components of the operating handle structure are operatively interengaged as shown in FIG. 4, the boss extension 67 is snugly yet rotatably received within sheave shaft chamber 76 with mounting pin 78 extending longitudinally through the handle boss bore 71. The outer end 79 of the mounting pin is shielded within the recess 73 in the handle boss so that no portion of the pin projects beyond the handle body to interfere in any way with operation of the hoist.

The pin, adjacent its outer end, it provided with means to retain the handle in place comprisinga peripheral groove 81 handle body, as seen in FIG. 4. For the major portion of its in which a splibring retainer 82 is received. interposed between the split ring 82 and an internal seat 83 defined by the shoulder 72 of the handle boss bore 71 is a coil spring 83. When split ring 82 is in place, the coil spring normally urges the boss extension 67 inwardly into the chamber 76 provided in the sheave shaft end the full extent until the handle body engages the outer surface of the casing cap plate 2 as seen in FIG. 4.

Longitudinal outward movement of the boss relative to the chamber may be effected by drawing outwardly on the handle against the urging of coil spring 83. Such outward movement is permitted to impart the multiposition selective engagement capability to the handle structure.

The handle structure described is operatively connected with the illustrative hoist operating mechanism described previously by means of adirect interconnection between the outer ratchet plate 31 and handle boss 64. Such interconnection is effected by providing the ratchet plate 31 with a noncircular aperture 85 therethrough which, 'in the preferred embodiment illustrated, comprises a polygonal opening defined by a multipoint star socket. Such star 'socketshown has twelve points which are adapted to receive therein the hexagonal projection 66 of the handle boss in any one of twelve operative positions. 7

When ratchet plate 31 and boss projection 66a're engaged, movement of the handle in the clockwise or counterclockwise direction will effect attendant movement of the outer ratchet plate in a similar direction (and the inner ratchet plate 29 and chain sheave 9 therewith) as may be permitted by the hoist control structure in accordance with its regulatory function on the operating pawl 23 and the holding pawl 22. Such regulatory control function, whether to permit up, down, or free chain control, is determined and, effected in the manner described in detail in Ratcliff U.S. Pat. No. 2,967,046.

Thus, with the construction illustrated and described, a

direct drive multiposition hoist is provided in which the operating handle is anchored directly to and pivoted in the sheave shaft for oscillation about the axis of the shaft. Such construction produces a simpler, more compact and lighter weight handle structure arrangement'than in prior known hoists. Also, and importantly, with such an arrangement the side draft resulting during actuation of the operating handle is reduced to a minumum because the longitudinal axis of the operating handle-is located as close as possible to the chain sheave 9 over which the load supporting chain passes, thereby minimizing the tendency of the hoist to cant during use.

Furthermore, the fact that'fie improved operating handle structure of this invention may be employed in a multiplicity of positions is important because it gives greater flexibility to the utilization of the hoist by the person employing the same.

The hoist of the present invention retains other advantages of the control structure of Ratcliff U.S. Pat. No. 2,967,046 in that no control components and no pawls are positioned on the operating handle, thereby precluding the possibility of damage to such control structure or pawls should the operating handle become bent or otherwise damaged during the rough usage to which hoists are commonly exposed.

Having thus made a full disclosure of a preferred embodiment of this invention, reference is directed to the appended claims for the scope of protection to be afforded thereto.

lclaim:

1. Improved operating handle structure for a load sustaining device which includes a rotatable shaft having a sheave thereon and means for regulating and controlling rotation of said shaft, such improvement comprising:

A. a manually graspable handle having a noncircular projection at one end thereof;

B. means rotatably mounting said handle relative to and directly on one end of said shaft and operatively and nonrotatably interconnecting said projection thereon with said means for regulating and controlling rotation of said shaft; and

C. means retaining said handle and said projection thus rotatably engaged with said shaft and nonrotatably engaged with said means for regulating and controlling rotation of said shaft, whereby oscillation of said handle effects and permits rotation of said shaft and said sheave therewith through the control affects of said means for regulating and controlling such shaft rotation.

2. The device of claim 1 in which said means rotatably mounting said handle directly on said shaft comprises:

1. a chamber extending axially into said shaft from said one end thereof; and I 2. a pin mounted in said chamber and projecting therefrom beyond said end of said shaft;

and in which said handle further includes:

l. a generally cylindrical extension on said handle extending beyond said projection;

2. a bore extending through said projection and said extension; and

3. said extension being rotatably received in said chamber with said pin extending through said bore.

3. Improved operating handle structure for a load sustaining device which includes a rotatable shaft having a sheave thereon and means for regulating and controlling rotation of said shaft, such improvement comprising:

A. a manually graspable handle having a boss on one end thereof, such boss including:

1. a polygonal projection;

2. a generally cylindrical extension extending beyond said projection; and

3. a bore extending through said boss and said projection and extension thereof;

B. a chamber extending axially into said shaft from one end thereof;

C. a pin mounted in said chamber and projecting therefrom beyond said end of said shaft;

D. a plate having a polygonal aperture therethrough;

E. means pivotally mounting said plate on said shaft adjacent said end of said shaft and operatively interconnecting said plate with said means for regulating and controlling rotation of said shaft;

F. said handle boss extension being rotatably positioned around said pin within said chamber with said projection engaged in said aperture in said plate; and

G. means retaining said handle boss thus operatively engaged with said shaft and said plate; whereby oscillation of said handle effects and permits rotation of said shaft and said sheave therewith through the control affects of said means for regulating and controlling such rotation.

4. The device of claim 3 which further includes:

H. a ratchet wheel on said shaft; and l. in which said plate comprisesa ratchet plate and supports a pawl thereon 'engageable with said ratchet wheel for effecting rotation 'of said ratchet wheel and said shaft therewith in response to oscillation of said handle in a predetermined direction.

5. A load sustaining device comprising:

A. a rotatable shaft having a sheave thereon which is rotatable therewith;

B. a load sustaining element engaged with said sheave with which a load to be sustained is engageable;

C. operating mechanism operatively connected with said shaft for regulating rotation thereof and said sheave therewith;

control structure for controlling said operating mechanism whereby said shaft and said sheave therewith may be rotated in a controlled manner so that up, down or free chain movement may be imparted selectively to said load sustaining element engaged with said sheave; and

E. improved operating handle structure pivotally engaged directly and operatively with said shaft for effecting and permitting rotation of said shaft during load raising and lowering, such handle structure improvement comprising: 1. an operating handle graspable by the user of said device;

2. a boss on said handle comprising a noncircular projection and an extension extending beyond said projection;

3. said extension being positioned in a chamber formed in an end of said shaft and rotatable therein;

4. said boss being operatively connected with said mechanism by said projection; and

5. means maintaining said handle boss, said mechanism and said shaft operatively interconnected, whereby movement of said handle may effect and permit attendant movement of said shaft through said operating mechanism.

6. The device of claim 5 in which said means comprises:

a. a pin mounted in said chamber and projecting therefrom beyond said end of said shaft;

b. a bore extending through said projection and said extension; and

c. said pin extending through said bore.

7. The device of claim 5 which further includes:

F. a casing in and on which said shaft, said operating mechanism and said control structure are positioned;

G. said shaft being maintained generally within the confines of said casing to obviate external projections therefrom; and

H. said handle boss extension being positioned in said shaft chamber within said casing to minimize side draft on said device when said handle is actuated to raise or lower a load engaged with said load sustaining element.

8. The device of claim 5 in which said handle structure further comprises:

6. a polygonal projection on said handle boss, and in which said operating mechanism comprises:

1. a plate pivotally mounted on said shaft and operatively connected with the remainder of said operating mechanism:

2. said plate having an opening therein defined by a multipoint internal star recess compatible in configuration with said projection on said boss; and

3. said boss projection being nonrotatably receivable in said star recess in many selective positions greater than two.

9. The device ofclaim 8 in which: 1

4. said boss projection is hexagonal in configuration; and

5. said star recess includes at least 12 internal points; whereby said handle boss is operatively and selectively engageable with said plate in at least 12 separate positions.

pin;

e. an internal shoulder in said bore; and

f. a spring interposed between said pin enlargement and said internal shoulder normally urging said boss extension into said chamber.

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