US2141310A

US2141310A - Coffee mill

Info

Publication number: US2141310A
Application number: US6348A
Authority: US
Inventors: David A Meeker
Original assignee: Hobart Manfacturing Co
Current assignee: Hobart Manfacturing Co
Priority date: 1935-02-13
Filing date: 1935-02-13
Publication date: 1938-12-27
Anticipated expiration: 1955-12-27

Description

Dec. Z7, 1938. D. A. MEEKER 2,141,310

COFFEE MILL Filed Fb. 13, 1935 3 Sheets-Sheet 2 M /af l' I 5, ,el As" I /al Z2 f. I /6' /s ZZ 6 /ez iii x22 1' Snnmtor Cttornegs Dec, 27, 1938.

D. A. 4MEEKER COFFEE MILL 3 Sheets-Sheet 3 Filed Feb 13, 1935 W 25mn-emot attorneys Patented Dec. 27, 1938 d A-.Meeker; Troy, Ohimass gnn'r i Manufacturing Company,-4 'I' QiineI3A-v3 of Fig."2,fFig,Bishowinglthejparts infthe shown a base l upon which' is mounted a housthe,

milk.,

Fig; 'z 'islam elevatinal view `with parts `breken a double-ended mill; and

Fig. 8is a detail view on the line 8-1-8of-Fig. 7. f y l s struction shown vwhich'-inciudesi-ftheYlwiperslfor A wings 46 which help to 'feed 'the y"ground"cieekintcfthe passage containing the Worm conveyor Ainember 4l, 4the discharge end of Whichvis provided Referring to the.'drawingswhichfshow a preferred`embodiment of the invention, there is ing ,H for enclosing the operative partis of the mill. The housing enclose's a. suitable motor 12,

and a coffee receiving hopperrlil extends above' the housing for receivingthecoieein bean form.

The hopper leads into the grinding means, and is controlled by means of a suitablegate valve I5 whichlis mountedupon a shaft i6 journalled in the frame portion IVIof the machine. A suitable handle i8 is provided'rfor theoperation` of the shaft. A spring pressed fdetent I9 cooperatesV attached to the =shaft' to yieidingly retain the f machine and Afitting within a suitablewrecessSZ Vformedin a'frame rnember53fattached to-"Ithe to' whichfthere is attached'an armv 22ope`rative1y with spaced recesses in a. cylindrical' section 20 handle I8 in either' open or closed position. l

An inward extension is provided upon shaft i6 connected to a link"23flThe link` 23 has operative connection with the motor switch`24, confveniently located-'within the housing to provide Ai'nf'ainrr'migeinem offtneirtary thereof and"y likewise haft-ass 'r fandto e conandlchaff. This is eifectedlby'meansfo withfeeding ribs of4 greater pitch, the'coifee issuing therefrom` 'passingr downwardly Iintof the 45 Means are provided for selecting the gradef'of 50 fineness to whifchfthe' coffee is to be ground. This means comprises the `hand wheel formed with a conical portion 5lfanda cylindrical Vfia'nge portionv fila,v extending toward the face of the 4voperation with a lfixed index, shown as arrows,

sponding index points on the cooperating nonmovable frame which permits of ready reading of the burr setting by the clerk on one side of the machine and the customer on the other; the indications naturally being, insuch case, so arranged as to be readily read from the opposite positions, as desired; the indications on the ro-rv tary member being shown as indicating letters 'corresponding to the setting of the grade selector mechanism. The hand wheel has a centrally located aperture through which there extends'a screw head 54 formed integrally with a disk 55 l which disk lis attached to a sleeve member 56 by means of a plurality of screws 51. The sleeve is provided with internal screw threads 58 andis rotatably `mounted within the hollow projecting flange of the stationary frame 53 with interposed bearing members 59 so that the sleeve 56 is freely rotatably mounted but is. held against axial movement.

The sleeve 56 engages with a threaded shaft 60 which is provided with a non-circular end portion 6 1 which extends through .a cooperatively formed non-circular recess in the frame member 53, thereby providing for axial movement of the shaft BIJ whilerpreventing. rotational movement thereof. A suitable contact or thrustmember `62 is attached to the end of shaft B0 for engagement with the cup shaped member 36 which encloses the end of the shaft 35 and the surroundl ing hub of the

burr

3,3, whereby controlled axial single hand movementthat is, within an anu guiar range of 180. Also, this -is of advantage where two sets of indications are desired to be used, as above described.

From the above it will be clear that when the hand wheel 50 is rotated, sleeve 56 is likewise rotated and is held in fixed axial position by means of the bearing members 59. Rotation of sleeve 56 produces axial movement of non-rotating shaft 60, toward or away from the movable burr 33 to provide for moving such burr closer to or farther from the stationary burr 32 and thereby to control the ilneness of the grind.

A locking disk 65 is seated upon the sleeve 56 and is adapted to engage, and frictionally lock with, aY shoulder E6 formed thereon and to be drawn up against such shoulder by means of a plurality of locking screws 61. When these screws are tightened, sleeve 56 is retained in a predetermined relationship with the hand wheel 50, but upon the loosening of the locking screws 61, the sleeve may be adjusted with respect to the hand wheel 50 by means of the screw head 54 to thereby properly adjust the position of the burr with respect to the indications.

Means are provided for normally tending to move the grade selector means in such direction as to adjust the burrs to their largest spacing, or to a non-grinding position. This means comprises an annually arranged spiral spring 10 slldably held, within a groove 1I, in the conical portion 5| of the hand wheel. One end of the spring 'abuts against a pin 13 fixed in the frame 53, and

the other end of the spring is engaged by a pin 12 carried by the hand wheel. Pin 12 engages with the endA ofthe spring and upon turning of the hand wheel causes compression of the spring sufilcient to return the grade selector means to its olf or non-grinding position when the hand 4 wheel is released. The spring is preferably preloaded, being of such length as to be under compression when the burrs are in the non-grinding position, i. e., off position of the hand wheel indications; andthe pins 12-13 are located out of line, so that as the spring expands to this off position each pin 12-13 will control the other. end of the spring which thus acts as its own energy absorber.

Means are provided for requiring an operation of the grade selector means away from the ofi position to a grinding'position before the mill can be started. Since this preliminary operation of the grade selector to a grinding position is required each time the mill is operated, there is more assurance that the operator will adjust theV mill in accordance with the wishes of each individual customer. `This means comprises an interlock member 15 pivotally mounted upon pin 16 attached to the frame 53 and having an extended end portion 11 adapted to ride upon the outside surface of the flange portion 5Ia of the hand wheel toward which it is urged by spring 18. The disk 19 attached to and rotatable with shaft 16 and the handle I8 which controls the grinding operation, is provided with a notch adapted to receive the opposite end 8l of the interlock member. The flange portion 5la is provided with a cut-away portion 82 which moves under `the end 11 of the interlock when the grade selector is turned to reach the olf or non-grinding position; this opening being sufficiently wide to permit oscillation of the hand wheel under the action of the shock-absorbing functioning of the spring 10. In such position the interlock member is turned on its pivot by means of spring 18 and the end 8l is caused to engage within the notch 80, thereby locking the handle I8 and preventing its movement toward on position while the gradeselector remains in non-'grinding position. Upon rotation of the hand wheel to any one of the predetermined grinding positions, the surface of 51a engages the end 11, causing the withdrawal of the member 8| from the notch 80, after which the control handle I8 can be turned to 'the on" position to start the operation of the mill, i. e. vto start the motor and to open the gate for the admission of coffee to the mili. As shown the spring18 is coiled about the pin 16 with one end bent about a pin 83 and the other end extended against aflxed lug or abutment 8|, tov urge the end portion 11 at all times toward the hand wheel.

Means are provided for latching the hand wheel in any of its predetermined grinding positions. This vmeans comprises a plurality of notches 85 formed between 'ratchet teeth on the interior of the flange portion 51a of the hand wheel. A latch member 86 is mounted upon a pivot pin 81 which 'is carried by the frame 53. A lsuitable spring 88urges the end portion 8 9 of the latch upwardlyinto the path of the teeth 85, and so into iatching position. These teeth are formed of such contour that the hand wheel can be turned in one direction, clockwise as viewed in Fig.A 3, without interference from the latching member. However, the latch, which engages successively in each of the' several notches and against the several teeth, will hold the hand wheel in any one of these predetermined positionsagainst -movement in the opposite direction; i. e., toward the coarser andnon-grnding positions.

Preferably the notches are so positioned as toand very fine. As shown the `spring 88 is coiled l about the pivot pin iiI` with one end hooked about a pin 88a carriedby'thelatch 86 and the other end abuts against the adjacentv portion of 53 and; the tension is such as to urge the latch toward the notches between the teeth 85. i l

` Release means is provided `for the latching mechanism which is` interrelated with the control handle I8 for controlling the operation of themill, this interlocking` means providing for the release of the vlatching mechanism only when the control handle I8 is moved into such position as to stop the operation o! themill. This means includes the` disk 19, rotated with -handle I8, which is provided with a camsurface 90 shown in dotted lines in Fig.- 3 which cooperates with a cam follower 9I` suitably mounted within frame 53. Spring 92 retains member 9i in engagement with the cam surface at all times. The member 9| is provided with anr outwardly extending finger 93, extending through a slot 94 formed in the frame member 53, which is adapted toerigage a tongue 95 formed upon the endof the latch arm In the position shown in Fig. 3, the grade selecting means has been adjusted to a grinding. position,` and the latch 86 retains the parts in such predetermined adjusted position, the control handle I8' being indicated in dotted lines for the on position. In this position the cam follower 9| has moved to its upper limit of travel andthe finger 93 does not depress the tongue 95, the end 89 of the latching member therefore remaining in the latching position., At the end of the .grinding operation, the handle I8 is moved to the off position indicated in dotted lines in Fig. 4 (stopping the grinding operation), where the cam frollower 9| is cammed downwardly, the iinger 93- depressing tongue 55, to thereupon causethe disengagement oi the end 89 ofthe latching member `from the notches 85, allowing the hand wheel to` be retur-nedtoits extreme end. or non-grinding position by means of spring 10, which also absorbs the shock of return when ther hand wheel is released, as described above.

A reset mechanism comprising a pin 98 mounted within the frame 53 and spring pressed'. outwardly, provides for withdrawal of ythe latch 86 when it is desired to momentarily release the latch from latching engagement, as Vfor the resetting of the grade selector to a coarser position. As will be obvious, no reset mechanism is required when the hand wheel is moved from a coarser to a finer position as the latching means e does not prevent such movement.

From the above it will be clear that the interlock member 15 and its associated parts prevent starting of the mill until the grade selector means has been adjusted to a predetermined one of 'the 'grinding positions. When so adjusted thescontrol handle can be moved to on position and the mill placed in operation. the grade selector mechanism being retained in the selected position. At the end of the grinding operation the control handle is turned to the oiI position, opening the motor switch and closing the gate, and simultaneously releasing the latching mechanism to permit the grade selectorto be returned to its non-grinding `position under the inuenceof spring 1U, inwhich ing mechanism;

position the interlock 15 again becomes effective as above described. y e

In order to restore the action of the latching mechanism 86 when the mill'hasubeen stopped, so that the grade selector will be retained in any adjusted position prior tothe opening movement oi the handle I8, means are provided for disabling vor withdrawing the action of the releasing nger 93 when the grade selectory has been returned 1 to non-.grinding position. To accomplish this re cam member IM carried upon the inner face of hand. wheely Slis adapted to engage the end portion IDZof the latch BB3-when the hand wheely has been returned substantially to its end or nongrindinggposition.v `This engagement, as shown in Fig. 6, produces a lateral swinging of the'latch member on its pivotl and withdraws' the tongue 85' from the path ci thel finger allowing the spring 88 to return the latch into latching relationship with the notches which are of sufiicient width to providev for vsuch engagement. Thus the release means, 9| etc., is disabled. and the latch is thereupon restored to latching posi` tion under the action of its spring 88 when the grade selector is moved back to its non-grind position. Under this setting the latch assumes the described lateral. position to be effective to retain the hand wheel in any predetermined grinding position irrespective of therelease means 81|, etc. which is then disabled, while the handle isalso locked against turning by the latch 'I5 and the grinding mechanism is` locked until the gra-de selector is thereafter moved to one of the grinding settings. When another grinding operation is to be performed, the operator Will-move the hand wheel to the desired grinding position which rocks ment thereof. As the hand wheel remains in any set position, he will normally set the gradeselector and then the `handle I8 to start they mill, thus avoiding the necessity for utilizing `two hands in theoperation of the mill.`

It is believed that the operation of the device will be clearly apparent from the above. Coffee is placed in the hopper I3 from a suitable container, the gate I5k being closed to retain the coffee in the hopper. If desired, the same container may then be positioned below the discharge outlet 41 to receive the ground coiee. The customers wishes having beenyascertained, the hand wheel is adjusted to the desired grinding position, and is retained there by the latch- If the .adjustment must be changed, the reset pin 98 may be operated to return the hand wheel toward its coarser positions.

The grade selector mechanism having beenL l Yelongated slotin the link prevents interference of the one operating rod with the other,` providing y mechanism of the mill which discharges a homogeneous ground material of predetermined fineness yinto the'container.

Attheend of the grindingoperation the handle I8 is turned to the off position, resulting in the unlatching of the gradev selector which thereupon is returned Ato its non-grinding position.

In such nongrinding position the interlock becomes effectivey to prevent a subsequent operation of the control handle i8 until the grade selector mechanism has been vadjusted toapredeterrnined grinding' position,

Figs. 'l and 8 show an arrangement adapted for a mill having asngle driving motor, two separate hoppers, and two separate grinding means.

Such amill, sometimes known as a double ended mill,m ay have the same grinding-means at each end, or mayf have differentrneans providing. for grinding v to different grades ofl neness.r The present inventionprovides for the controlled operation of `a double ended mill in a manner similar .to'lthat described abovefor the single ended pair of overhanging shafts |22.

min. I i, v

I1`le rrlo 'tor` |20` i'sarrangedy substantially centrally of the casing |2 and is provided with a Grinding means .|23 of the constructionldescribed above, are suit- `ablyjmounted and operated by `the respective shaftsin the-manner described above.

` Separate hoppers |24 are associated with theA respective grinding means, admission of the coffee to the hopper'sand the grinding means being; controlled respectively by the gates I5. mounteduponshafts which are actuated by con- 351trol handles I8.

The gates are Grade selecting means are positioned at each 4Vend ofthefmachine, each of which may be con- -structedin exactly' the same manner as described in detail above for the single-ended mill. The detailed construction of the interlocking mecha- "nism is preferably a duplicate oi that described' above-.for` the single-endedniill, and further 'description'is therefore unnecessary. v

`(Means are provided forcontrolling the actua- .t'ion-ofgthemotor vfrom either end ofthe mill.

For thislpurpose'theshafts I6 are provided with I crank arms 22' to which are connected operating Prods` |32, each rod being provided with a link same controlled interlocking of the grade'selector i mechanism with each control handle as with a.

75 single ended construction. j Before the", control |33 having'an elongated slot|34 formed therein.

The motor ,switch |35 is preferably positioned betweenthe rods |32 and spring means |36 tends to yieldingly .urge the switch toward theoff position.

The switch is provided with an operating memberf|3`| which carries a cross bar |38 having sliding" engagement in both slots |34. vThe construction is such that when both control handles |8 are in theoff position, as illustrated for instance by the left hand end; of the mill in Fig. 7, links |33 Yare'drawn upwardly and the spring |36 causesthe operation of the switch arm |31 However, upon the operation lof either or both control handles to on position,v illustrated in the right hand end of the mill of Fig. l, link |33 engages the rod |38'to cause'acto offf position.

tuation of the switch to the on positionfv The forfthe actuation of the motor'swtch to on positionwhen either operating handle is moved to on position. l v

i s will be clearly evident fromthe foregoing description, this arrangementI providesfor the 'ing' operation, the control lever ismoved to the .off position, Which `releases the grade selector mechanism which thereupon is returned to the oil. :or non-grinding position by its resilient means. Movementof the control handle at one .end of the mill to the oi -position also effects the closing 'of the associated gate, and the stopping of the motor provided the other end of the mill is not inr operation. In case the other end of the mill is in operation, I'the motor will not be stopped'until both control handles'are turned to the off position, but a subsequent operation of that end of the mill and the opening of its' gate will be prevented untilafter the grade selector mechanism at that end h as been readjusted to a desired grinding position.v

While the forms of apparatus herein described constituteA preferred embodiments of the invention, it is to be understood that the 'invention is not limited to these precise forms of apparatus, and thatchanges may be made therein Without departing from'the scope of the invention which is defined in the appended claims.

What is claimed is:

1. A coffee mill of the character described comprising ahousing, a motor, grinding means drivenby said motor and located within said housing,

'grade selector means for said grinding means adjustable fromy anon-grindingposition to a "plurality of grindingpositions', resilient means effective to move said grade selector means'to non-grinding position, releasable means inaccessible within said mill for retaining saidl grade selector. means in any selected grinding position against returnmovement, and reset means accessible from outsidesaid casing for releasing said retaining means to provideV for the readjustrnentof said grade selector means.

v, v2. 'A coffee mill ofthe character described corn- Vprising ra motor, grinding means driven thereby,

grade selector means for said grinding means adjustablefrom a non-grinding position to a plurality of grinding positions, means tending to move said grade selector'means to said nongrinding position, releasable means for retaining saidfgrade selector means in any predeteryminedgrinding position, means forv controlling )the grinding of coffee, means operable upon the actuation vof said controlling means to stop the grindingof coffee for releasing said retaining means to allow said grade selector means to return to's'aid non-grinding position,I and means effective upon the return of said grade selector means to said non-grinding lpositionffor disabling thel action of said releasing means.'

31 A coffee millof the character described comprising a motor, a motor switch having an operating member, vgrinding means 1 driven by said motor, grade selector means for said grinding means adjustable from a non-grinding position f to anyone of a plurality of grinding positions,

means tending to move'said grade selector to non-grinding position, said means comprising a coiled spring under compression, and relatively movable means connected tothe opposite ends of saidspring arranged to overrun after the grade selector means is moved to off position whereby the said spring acts to absorb the en- V ergy of movement, releasable means for retaining said` grade selector means in `any selected 3' l grinding'position and means operated by the motorswitch operating member for releasing said `retaining means,'..whereby the grade'- selectorv means will be returned tooff action of said spring; i ,i l .l

4. A coffeemill ofthe `character described .com1 prising a'motongrindin'g means, grade 'selector' position under the means forl said 'grinding meansadjustable frOm anon-grinding position toaplurality of grind- A ing positions, a motor sivitcli` and .a' handle for grade selector means, a stop pawl positioned adjacent said handle with one end :cooperatively engaged with the said grade selector means, andv theotherend adapted to be moved into stopt-y.y ping engagement with a stop memberupon said handle, means for urging said pawl into stop- 1 pingengagement `with said stopmember, and

means carried by vsaid grade 'selector effective, i upon said pawl within a predetermined portion i of therange of -movement of :said grade selector `member to move said pawl out of' locking `engagement witht'hesaid motor switch handle, said means being positioned to move said' pawl outy of locking engagement after'the grade selector means is movedfrom the oii' position tothe first grinding position. n n

5. Acoiee mill of thecharacter described comprising motive means, a plurality of hoppers, a

pluralityk of grinding 'means vdriven by' said motive means and associated respectively withjsaid plurality of `hoppers, gate means. for controlling admission of coffee from each' hopper into `its f associated grinding means, grade selectormeans -and-means preventing a subsequent opening of a closed gate means until after the adjustment of the grade selector means associated therewith to f a grinding position. i,

6. A coffee mill of the character described comi prising motive means,` a plurality of hoppers, a

plurality .of grinding 'means drivenl by said motiverneansv and'. associated respectively with saidv plurality of hoppers, gate means for vcontrolling admission` of coffee` from eachA hopper .into its associated grinding means, grade selector means for each grinding meansadiustable from a noni grinding position to, aplurality ci grinding lposi-` tions, means tending to move each grade selector means to its non-grinding position, releasable means for locking each lsaid, grade selector means in any of its selected grlndingpositions, means effective rupon the closing of any'of saidgate i means for releasing the associatedlocking rneansA to allow the grade selector means :associated therewith to return to its non-grinding position, means preventing a subsequent opening of a closed gate means until after the adjustmentjof' the' grade selector meansassociated therewith. to a grinding position, and means effective when any o f said gate means is opened for starting said motive means and for stopping said motive means when none of said gate means is in open position.

7. In a coil'eel mill provided with a motor,

grinding means operated thereby," gradefselector means forisaid grinding means adjustable fromy a non-grinding position to a plurality of grinding-positions, resilient means'` effective to' movev` said grade selectory meansv to non-grindingposil, tion, la motor switch, a gate'for` controlling the admission of coffee to said grinding means, and'` a commen-control member for said Vgate and said switch providing for opening movementof said gate concomitantly with closing movement of operating said switch positioned adjacent said: theswitch;v means eiectivefor.controlling'the' for retaining thev grade selector means inany selected lgrinding position against returnjmove@ ment prior to operation of said control member to "effect the closingof said gate. and 'theop'lening ofA said switch-member, andV lmeans, operable` upon closing said gate for withdrawing saidf latch' means from latching position 'to provide for return of said grade selector "to 'non-grinding position. f

8. A conelnuu of the character' 'described com j prising a motor, grindingmeans, gradeselector means for said grinding means adjustablejrom a non-grinding position toa plurality of grinding positions, means tendingto movev said grade seing means for preventing'movement of said grade selector means from a. grinding position toward a i coarser grinding position whilev permitting movement vthereof toward a finer grindingtposition. v

comprising a motor,v grinding means, vgradeseoperationgoi'- said mill comprising latcl'iing",meansl 15 lector means to non-grinding position, and retainf30 l `9.r A coffee v'mm2 f the character described .35

lector means for said grindlng'means adjustable from a non-grinding'position` toa` pluralityy of grinding positions, means tending to move, said grade 'selector' means to non-grinding position, retaining means for preventing movementof said grade'selectonmeans from a grinding positiontowarda lcoarser grinding position while permitting movement thereof toward a liner-grinding position, and means under thecontrol of theoperator for releasingv saidretaining means-5to provideior thefreturnof` said grade selector means toward a coarser grinding position and toward said non-grinding position;` f p10. A' coffee mill of` the character described lcomprising amotor', grinding means,` a gate for controlling the introduction of coiee to said grinding means, 'gradeselector means for ,said

grinding means adjustable from a non-,grinding position to a plurality of grinding positions, means tending to move saidgrade selector means .to 'l non-grinding position, retaining meansfor pre.- venting movement ofsaid grade selector means from a grindingposition ltowarda position` of coarser grindjwhile providing for movement thereof toward a position of-,ner grind, and means controlled in response to' movement of said gate ltoward closed position for releasing .said

retainingmeans and providing for the` returnf ofv said.` grade selector means to non-grinding position.. ,4 l

11. A mill of the character described comprising a motor, a motorjswitch, grinding meansoperated by" said motor, grade selector means for said grinding means adjustable from a non-grinding position vto `a plurality of grindingpositions, resilient `means effective to move saidy grade selector meansto non-grinding position, a gate for controlling admission of material to be ground tosaid grinding means, a control means for saidk gate and said motor switch operable from an oil! position to an on position vto open said gate and energize said motor, and latching means operative when said control means is' in oil position and during the subsequent movement thereof to on position for y retaining vsaid grade selector means in any selected grinding position against return movement.

12. A mill otlthe character described comprising a motor, Y grinding means, grade selector means for said grinding means adjustable from a non-grinding position to a plurality of grinding positions, resilient means eective to move said grade selector means to non-'grinding position, a gate for `controlling admission of material to be ground to said grinding means, .latching means' operative when said gate is in closed position and during the subsequent movement of the gate to open position for retaining said grade selector means 'in any 'selected grinding position' against return movement, and means operable upon the closing of said gate` for effecting withdrawal ofsaid latching means to provide for return ofsaid grade' selector means to non-grinding position. v

13. Inl almill of the character described provided withjamotor, a motor switch, grinding means operated by said motor, grade selector means for said grindingmeans adjustable from anon-grinding position to a plurality of grinding positions, resilient means eiective toV move said grade selector means to non-grinding position,

and latching means operable when said switch is in circuit opening position andduring the vsubsequentclosing thereof for retaining said grade selector means in any selected grinding position' against return movement.

14. In `a mill 'of the character described provided `with va motor, a motor switch, grinding means, gradev selector means i'or said grinding means adjustable from a non-grinding position to a plurality o1* grinding positions, resilient means eilective to move said grade selector means to non-grinding position, latching means operable when said switch is in circuit opening position `and Aduring the subsequent closing thereof for retaining said gradeselector means in any selected grinding position against return movement, and means operable upon the opening of said switch for effecting withdrawal 'of said latching means to provide for return of said grade selector means to non-grinding position.

15. A mill of the character described provided with a motonxsw'itch means therefor, grinding means, grade selector means for said` grinding means adjustable from a non-grinding position to a plurality -of grinding. positions, resilient means eiective to move said grade selector means to non-grinding position, latcliing means for r'etaining said grade selector means in any selected grinding -position against return movement, means operable uponoperation of said switch to openr circuit position for effecting withdrawal of said latching means to provide for return of said grade selector -ineans to non-grinding position, and means f; ,operable in the non-grinding position of. said grade selector for restoring vthe action of said latching means in preparation for a subsequent cycle of operation of the mill.

16.l A .mill of the character described provided with a motor, grinding means, grade selector means for said grinding means adjustable vfrom a non-grinding position to a plurality of grinding positions, resilient means effective to move said grade selector means to non-grinding position, a gate for controlling admission of material to be ground to said grinding means, latching means for retaining said grade selector means in any selected grinding position against return movement, means voperable upon closing of said gate for effecting withdrawal ot said iatching means to provide for return of said'grade selector means to non-grindingrposition, and means operable in the non-grinding position of said grade selector for restoring the action of said latching means in preparation for a subsequent cycle of operation of the mill.

'17. A1 coffee mill of the character described comprising a motor, grinding means driven thereby, grade selector means for said grinding means adjustable from a non-grinding position to a plurality of grinding positions, means tending to move said grade` selector means to said nongrinding position, releasable means for retaining said grade selector means in any predetermined grinding position, means i'or controlling thegrinding of coffee, means operable upon the actuation of said controlling means to stop the grinding of' coffee for releasing said retaining means to allow said grade selector means to re- ,turn to said non-grinding position, and means effective' upon the return of said grade selector means to said-non-grinding position'for disabling the action of said releasing means.

18. A coifee mill of the character described comprising motive means, a plurality oi hoppers, a plurality of grinding means driven by said motive means and associated respectively with said plurality of hoppers, gate means ior controlling admission of coffee from each hopper into its associated grinding means, grade selectormeans for each grinding means adjustable from a nongrinding position to a plurality of grinding positions, means tending to move each grade selector means to its non-grinding position, reieasable means for locking each said grade selector means in anyof its selected grinding positions, and means effective upon the closing of any of said gate means for releasing' the associated locking means to allow the 'grade selector means associated therewith to return to its non-grinding position.

i9. A coffee mill of the character described comprising motive means, a plurality of hoppers, a plurality` of grinding means driven by said motive means and associated respectively with said pluralityof'hoppers, gate means for controlling admission of coffee from each hopper into its associated grinding means, grade selector means for each grinding means adjustable from a. non-grinding position fto a plurality of grinding positions, means tending to move each grade selector means ,to its non-grinding position, releasable means for locking each said grade selector means in any of its selected grinding positions, means `effective upon the closing of any of said gate mea-nsfor'releasing the associated locking means to allow the grade selector means associated therewith to return to its non-grinding position, and control means for causing operation of said motive means to drive said grinding means when Fany of said gate means is in open position and for stopping said motive means when none of said gate means is in open position.

DAVID A. MEEKER.