US2484770A - Adjustable rack and pinion gearing - Google Patents

Description

Oct. 11, 1949. J. H. WORTHEN ADJUSTABLE RACK AND PININ GEARING III Filed Oct. 17. 1944 mvEN-ron gfo/f' H War/a E Mw ATTORN EYS a hand for moving over a dial.

Patented Oct. 1l, 1949 vA DJUS'IBLE RACK AND PINION GEARINGl John H. Worthen, Providence, R. I., assignorto Federal Products Corporation, a corporation of- Rhode Island Application October 17, 1944, Serial No. 559,072 'I This invention relates to a dial indicator.

A dial indicator of the type referred to consists oi a casing and a gear train mechanism within that casing forV multiplying and conveying movement oi a contact plunger or iinger to The casing usually provides a front wall which has mounted therein a bearing for the staff upon which the indicatingv hand is mounted. This bearing is usually carried by this front plate oi the casing and remains with this frontplate at all times. Thus, when the gear train mechanism is withn drawn the staff is drawn out of this bearing.

Little or no trouble is experienced in this type` of mounting when the gears in the gear train are all complete circular gears. However, when segmental gears are used the looseness of the staff when Withdrawn from the bearing of the front plate frequently permits many of the gears of the gear train to come out of mesh and considerable difficulty is experienced in the positioning of the gear train mechanism in a casing so that it will properly operate.

One of the objects of this invention is to provide an arrangement so that the gears of the operating mechanism will not become disengaged through handling and prior to or during the as-' sembly of the mechanism in its case.

Another object of this mechanism is to provide a unit which will be substantially complete and will not depend upon any bearing in the casing for the mounting of any part of the mechanism.

Another object of this mechanism is to provide an arrangement completely independent of the dial hand staff for centralizing the gear train mechanism in the casing.

Another object of this invention is to provide an arrangement so that a movement may be had of the gear train mechanism and the operating rack of the casing so that a convenient assembly of the two with the proper meshing of the pinion and rack may be had.

With these and other objects in View, the invention consists of certain novel features of construction, as will be more fully described and particularly pointed out in the appended claim.

In the accompanying drawings:

Fig. 1 is a top plan View of a dial indicator of the type which is the subject of this invention;

Fig. 2 is a section approximately on line 2 2 1 Claim. (Cl. i4-422) oi- Fig. 1 butA showing some of the operating parts in full instead of in section;

Fig. 3 is a fragmentaldetail of one part of the casing;

Fig. 4 is an edge View of the separable unit which is placed in the casing; v Fig. 5 is a plan view of the casing prior to the assembly of the unit therein;

Fig. 6 is a plan viewof the vvunit for assembly in the casing in Fig. 5;

Fig. 7 is a view similar to-Fig. 5 but showing the unit of Fig. 6 assembled in the casing with the gearing beneath the-plate of the unit dotted to show the relative position thereof. In proceeding with this invention, I provide a pair oi plates held in spaced relation for mount-V ing the complete gear train and dial hand stall for the transmission of motion to the dial indicator. One of these plates is so shaped as to fit snugly with the casing in which it is to be assembled so as to centralize and hold the movement in position therein. The stai for the dial hand has its bearings in the plates and extends through an opening in the front plate of the casing out of contact with the walls thereof.

With reference to the drawings I designates generally a casing which consists of a cylindrical side wall II and a front wall I2 having an opening I5 therein. A stem I3 having a bore I4 extends from the side walls as shown in Figs. 2 and 5. A back Wall or cover I6 ts into a recess I'I in the side wall II and is secured in place by screws I8 engaging the threaded openings I9 in the bosses 2D formed integral with the side wall A plunger 2| is slidably mounted in the bore I4 of the stem I3 and is provided with a rack 22 formed therein. A pin 23 extends from this rack and the plunger is moved outwardly from the casing by a spring 24 which engages the pin 23 and is anchored to one of the bosses 20 or to the securing screw which extends therethrough.

A complete unit designated 25 contains the operating mechanism for the indicator and m'ay be positioned into the casing or taken bodily therefrom. This unit consists of a front plate 26 and a back plate 21. These plates are spaced apart by a plurality of posts 28 held by screws 29 in xed relation to the plates 26 and 2l, which provides a framework in which the movable parts of the indicator are mounted. A stai 30 is rotatably mounted in both plates in bearings 3| and 32 provided in these plates. These bearings have a press ilt with each of the plates and remain as a permanent part of the unit assembly. A gear or pinion 33 is mounted on this staif 30. A segmental gear 313 is mounted on shaft 35 having bearings in the plates and engages the pinion 33. Upon this shaft 35 there is also mounted a pinion 36 so as to rotate with the shaft 35. Another segmental gear 3l mounted on shaft 38 having bearings in the plates meshes with pinion 3G while a pinion 39. is mounted on shaft 38 so as to rotate therewith. The pinion 39' is -for en.- gagement with the rack 22 on the plunger 2|.

Another segmental gear 40 is mounted on fai gear and the pinion in one.directionL thefary rangement being such as to bring the pointer back to zero as well as assisting in. returning A suitable springiW-facts upon-this the gear mechanism to zero 'and "causing the' plunger to move out of the casing.

The entire unit 25 ist-positioned in the casing .l-'L sothat the sta' 3U extends throughpthe opening I5 in the front/wall. |2 thereof. The points 115.45475, 1.8,l ofthe plate 27|, engage.1 rthe inner surface Yofthe cylindrical wall ofythe asingsoasto Alocate the. unit -ina position `so that the staff V3|) passes:1 through the opening lwithoutoontact with.A the edges thereof. In positioning this unit inithe fcasing., pinion; 38,- will be rst. located somewhat -r to:- the left of; the' rack 22 andthen'by'turning thefunit such asshown irl-Fig 6. or; ff counter-clockwise. the pinion/33 will be brought intgokengagement Withvthe, rack so thatthe. teeth: of the twowill-,properly mesh. Any desired entrance-of the-teethone- With-the othermayf be, lobtainedby 'the rotationI of the unit 25m-.the casing.. WhenY this desired-:amount hasbeenfobtainedfthe casing; will' .bef looked in position by. pressure-of thefcover againstz'the-'unit l forcing the front Wall 26 thereof snugly against the front Wall l2 of the casing.

After this assembly has been had a suitable dial 5U will be positioned on the front Wall l2 of the casing. A dial hand 5| will be provided on the staff 30 and a glass cover or lens 52 mounted in bezel '53 may be positioned over the dial and hand so as to protect the same.

The projection54 on the rear wall IS will serve for mounting the dial in suitable location.

It will be readily apparent that with the unit 25 assembled prior to positioning in the casing none of the gears may becomedislodged or out of. mesh bfyfreason of suchpositi'oning. Also by reason of the unit being rotatable to position Athe pinion into the rack a proper mesh may be had between the parts.

claim-z vA dial. indicator comprising a casing, a rack 20,;movable in and. out of said casing, a unit containing.. operatingy mechanism and a pinion to mesh with said rack, said unit comprising a pairof' platesv one of which ts the inner surfaces-.of said casing to locate the unit therein and is movable With reference to the casing to cause .engagement of saidpinion with said rack until the. desiredfm'esh. ot raokand'pinion is obtained. l

JOHN H. WORTI-IEN.

REFERENCEsV CITED The;- following references Vare; ofy `record in 'the l'e of. this patent; Y l

' UNITED STATES PATENTS lliluxn'ber A Name. Date l 517.54m Trowbridge Jan. 19,1897 894.314 Cashmere July 28, 1908 1.119.256 gaten. Dee. 1,*1914 4,439,738 v Howland -oct 3,`r 1922 1,637,024. 'Maynard July-26, i927 y12,093,308', cook sept. 1.1171933-

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