US1745840A - Quern - Google Patents

Description

S. BJERRE QUERN Feb. 4, 1930.

2 sheets-snm 1 Filed Jima 9. 1928 S. BJERRE Feb. 4, 1930.

QUEEN v 2 Sheets-Sheet 2 Filed June 9. 1928 Patented Feb. 4, 1930y tiene PATENT orrlcr.

SILIAM BJERRE, OF SKIVE, DENMARK QUEEN Application filed .Tune 9, 1928. Serial No. 284,093.

rlhe present invention relates to a quern of the kind comprising a rotary and a nonrotary grinding body between whichthe substance to be ground is introduced, the said -substance being, perhaps, grain, cacao, coffeek or some other similarl subst-ance.

In quernsy of this nature it has previously been proposed to journal the grinding bodies in such a mannerthat excessive loading of vl the quern kwill cause one of the grinding 'bodies to be displaced away from the other one. f

This relative displacement of the grinding bodies is effected either by the material to be ground between the grinding surfaces pushing the rotary grinding body away from the non-rotary grinding body and, at the same time, compressing a spring which holds the' t rotary grinding body in Contact with the material tovbe ground, or by the friction between the grinding bodies and the material to be Ojround, which friction is highly increasecllby overload on the quern and causes a rotation of the non-rotary grinding body, whereby the *latter moves axially away from the rotary grinding body. In the last mentioned caseV the rotation of the non-rotary grinding body has alsobeen utilized to reducevthesupply of material to thequern by displacing the feeding device for 'the material to be ground. y v

vThese heretofore known querns, however, and themethods used for regulating .the same `suffer from various drawbacks. Then the relief ofthe quernduring an overload is effected by displacement of the runner, this displacement as a rule causes compression of Vthe spring `pressing the runner against the material to be ground. This compression. however, increases the spring power and, consequently, the pressure at which the spring presses the rotary grinding body against the material.l lf-the overload is due for instance to al hard foreign body entering-between the grinding surfaces, 4then the displacement fof the rotar] grinding body will consequent-ly cause the pressure between the said foreign body and the grinding surfacesA to be increased, the consequence of which may be a `total destruction of the grindingsurfaces.

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If the above mentioned rotation of the nonrotary grinding body is utilized to regulate the load, then the said body must be adapted to rotate as well as to be displaced in axial direction,and according to circumstancesv the construction of the quern may consequently be complicated and expensive.

One of the objects of the present invention is to produce a quern by which, in case of overloading, a relief is effected automatically by an axial relative displacement of the two grinding bodies, without the pressure between the latter and the material be ing thereby increased, which advantage is attained by journalling the quern housing in such a manner that the said housing, when the friction between the grinding bodies and the material to be ground exceeds a certain permissible value, is swung through a larger or smaller angle in the direction 'of rotation of the quern shaft, whereby a displacement of the grinding surfaces relatively to one another is effected.

Another object of the invention is to utilize the said rotation of the quern housing for reducing the supply of grain to the quern, the said reduction being attained by arranging a tappet on the quern housing to engage a shaking tray, which is kept in motion by means actuated by the quern shaft and which serves to supply the material to the feeding aperture of the quern housing, and to push the said tray away from the said means.

A further object of the present invention is to employ means by which the distance between the grindingsurfaces may be adjusted to any desired extent, in such a manner that the degree of fineness obtained by the grinding treatment may always be determined at will.

Still another object of the invention is the provision of means by which the grinding bodies may be moved manually away from one another by a rotation of the quern housing by hand. n

Finally the invention relates to means by which the quern housing is attached in such a manner to a frame in which it is journalled thatl thev quern housing, when actuated by the friction between the grinding surfaces, 100

will not rotate until the load on the quern and, hence, the said friction, has exceeded a certain limit.

Still another object of the invention is the use of means by which the grinding bodies may be `moved manually away from one another by a rotation of the quern housing by hand. y

Further details of the invention will appearfrom the following description of the constructions shown on the drawing.

Fig. 1 is a central vertical section of a quern constructed according to the invention,

Fig. 2 is an end view of the quern, with parts in section, and

Fig. 3 is a section of the quern along the line B-B in Fig. 2, n

Figs. 4 and 5 are views corresponding to Figs. 1 and 2, but showing another construction of the quern,

Figs. 6 and 7 represent a detail of the construction shown in Figs. 1 and 2, in cross-section and in longitudinal section, respectively, and

Fig. 8 is a diagrammatic viewof another construction of the quern, in side elevation.

6 on the quern case.

1V is a frame shaped as a hollow post, and 2 is a mainly cylindrical quern housing formed on one side with a projecting hollow`trun nion 3 by which the housing 2, referred to in the following as the quern case, is journalled in the frame 1.

In the quern case there is fixed a mainly annular grinding body 4 with a central cavity 5 communicating with a feeding channel 7 is a shaft which is journalled in the trunnion 3, in ball bearings' 8 inserted in the same. One end of the shaft7 extends into the quern case and supports there a grinding body 9 disposed opposite the grinding body 4. 10 is a helical spring inserted in the trunnion 3 so that it encircles a portion of the shaft 7 and exerts an axial resilient pressure on the latter, which pressure maintains the grinding body 9 in resilient contact with the material contained between the grinding bodies. One end of the spring l() rests against one of the ball bearings 8 in which the shaft 7 is free to move axially, and the other end of the spring rests against an eccentric 11 which is fastened on said shaft and the function of which will be described more fully later on. 12 is a belt pulley fixed on the shaft 7 beyond the end of the trunnion 3 and serving to rotate the shaft 7 and the grinding body 9.

The material to be ground in the quern is introduced into a hopper 13 supported by brackets 14, Fig. 2, which are attached to the frame 1. The hopper 13 dischargesr at vlboty tom into a so-called shaking tray 15, one end of which is pivoted about a pin 16 on the hopper, whilevv the other end projects-out to, andoverlies, the feed channel 6 on the quern case.

17 is a rod which extends out through the hollow frame 1 and is guided at both ends by suitable holes in the same, one end of the said rod resting against the periphery of the eccentric disc 11, while the other end rests vagainst the bottom of the shaking tray 15 as shown by Fig. 1.

0n the end facing the quern, the channel 6 is fitted with an arcuate projection 18.Y

Between the latter and a flan-ge 19 on the bottom portion ofthe frame 1 there is inserted a resilient member consisting of a. rod 2O -the upper end of which is threaded and rests against the bottom side of the projection 13, while the` lower end-of the rod is adapted to slide in a conical guiding block 21, the bottom end of which is journalled inthe flange 19 by means of a pin 22. Around the rod 20 and the guiding block 21 there is inserted a helical spring'23 the bottom end of which rests against a flange 24 on the gui'dingblock 21 and the top end of which rests against a cupped washer 25 which is inserted on the top end of the rod 21 and is held in position against the pressure of the spring 2O by means of a nut 26. By tightening up this nut it bev comes practicable, without altering the length of the entire device consisting of the rod 2O,V

the spring 23 and the guiding block V21, to regulate the spring pressure and, thereby, the force with which the spring tends to turn the quern case in the direction indicated by the arrow in Fig. 2 which is opposite the direction of rotation of the grinding body 9.

The tension of the spring 23 is adjusted in such a manner that the quern case will remain in the position shown in Fig. 2 as long as the quern is in use without being overloaded, since the power of the spring 23 will counter-k balance the torsional moment due to the friction between the grinding bodiesand tending to rotate the quern case in a direction opposite the direction of the arrow in Fig. 2.

The ball bearing 3i nearest to the rotary grinding body 9 rests on'one side against the eccentric sleeve 11 and on the other sidel against a ring 27 inserted on the 'shaft 7, see

Figs. 1 and 3. The sideof the ring 27 facing'the grinding body 9 rests kagainst the slotted central portion 28 of an arm 29 which is disposed inside `ofa bore y30 on the side of the quern case facing theframe 1, and is attached to the quern case at both ends rby'means of a bolt 31, Fig.Y 3, which passes through the quern case and through a washer Y 32 disposed on the outside of the latter; a hand wheel 33, Fig. 3, being provided on the bolt 31 outside ofthe said washer. Both ends of the arm 29'are attached to the quernkr vcase in the above `described manner, so that by. tightening up the handkwheels 33, one of which is shown in Fig. 2 and the otherone in Fig. 3, the central portion 28 of the arm 29 extending transversely through slots 34 in the trunnion 3, but outside of the sha-ft 7,

kmay be pressed more-or less. forcibly against 31-mayjserve to adjust the distance between thegrinding surfaces 35 and 36, rrespectively/,on the two grinding bodies 4 and 9, since fa rotation of the hand ywheels 33 will cause a displacement of the ring 27 towards the spring 10 and, thereby, a compression of the latter simultaneously with an aXialdisplace- .ment of the shaft 7 and the grinding body 9 away. from the grinding body 4. In this manner it becomes practicable, by adjustment of the hand wheels 33, to attain any desired distance between the grinding surfaces 35 `and 36 and, hence', any desired degree of finenessv of the ground material.

To a lug 37 on one sidef of the frame 1 therey is attached, by means of a screw 38,

a curved rail 39, the lower end of which is fork-shaped and passes through a recess 40, Figs. 3, 6 vand 7, in the washer 32. provided between thequern case and one of the hand wheelsk 33.l f

The end ofthe recess 40 facing the rail 39 has a sloping bottom face 41, and the rail 39 is fitted with a corresponding sloping face W42, Fig. 3.

lThe quern described acts in the following manner: When the shaft7 is rotated by means of the pulley 12, the grinding body 9 isthereby caused to rotate, and the eccenftric sleeve 11 on said shaft moves the rodv 17 up and down and, consequently, alternately lifts and lowers the shakingtray 15, thusy causing the latterto oscillate about the pin 16- The material fed into the hopper 13 falls vtherefrom upon the shaking tray and, actuated by the motions ofthe tray, travels longitudinally through the said tray and f drops down into the channel 6, whence it f passes by way-of the aperture 5 in the grinding body 4, to the grinding surfaces 35 and 36. After being ground the material leaves the quern by way of a discharge spout 43 on the side vof the quern case, whenceit is -v caught in a .box 44 .serving to'store it and to support the post 1. The material may be directed from the spout 43 to the box k.44 by anyy suitable means such as hose, a bottomle'ss bag or the like, one end of which is joined lto the spout 43 while the other endV is inserted into the boX 44 by way of Van aperture (not shown) in the same.

The limits of the vpresent invention will not be' transgressed by omitting the box -44 and by discharging the' material from the spout 43 into any other devices ofk known nature, such as bags,.boxes, pails and the like. As shown by Figs. 1 and 2 the quern castI is split and itsk members joined together by meansV of screws 46. The grinding body 4 is attached to the quern case by means of i a suitable number of screws 47 which are screwed eitherv directly into the grinding body for instanceby more grain being fed into the quern than the latter is able to grind, or by some foreign body penetrating between the grinding surfaces, then the friction produced between the material and the rotary grinding body, which friction yreacts on the grinding body 4 fixed to the quern case, will cause the latter, when actuated by this friction, to rotate in a direction opposite the arrow in Fig. 2, whereby the spring y23 will be compressed.

This rotation will bring the sloping face 41 of the recess 40 in the washer' 32 towards the sloping face 42 on the rail 39 which will cause the washer 32 and, hence, the bolt 31 `and the end of the arm 39 connected thereto,

to move in the direction indicated by the arrow in Figs. l and 3, whereby the central body 9 back into the position corresponding to its original adjustment. Provided that the overloading is due to excessive filling of the quern channel with material it will be suitable, in case of overload, to reduce the supply of grain to the channel. This reduction is attained by the provision, on the periphery of the quern case, of a cam y49 (Fig.

2) the wedge-shaped face y50 of which projects down below a lug 51 on the under side of the shaking tray. When the querncase is rotated in consequence ofy an overload, the sloping face 50 of the, cam 49 will strike the lug 51 from below and lift the shaking tray 15` so far that it will clear the top end of the rod 17, which latter cannot thenk actuate the shaking tray any more. The tray will therefore become stationary, and the passage of material-along the tray and, consequently, the supply of'material into the feeding channel will therefore bek reduced very considerably.

On a boss 52 on the side of the quern case there is pivoted by means of a pin 53, Figs. 2 and 3,a leverfcomprising a handle portion 54 and a head or cam portion 55, the periphery of rwhich rests against the frame 1. p

By rotation of the lever about the pin 53, in such a manner that the periphery of the cam 55 is forcedV to slide against the frame 1, the quern case may be turned by hand against thev action of the' spring 23 wherebyk the cri grinding bodies are removed "from one 'another in the above described manner.

tion of the present quern in which the frame of the quernfcase, instead of providing one single bearing for journalling the quern case, providestwo bearings 60 and 61, respectively, serving to support the same. The quern case which, in this construction also, is mainly cylindrical, with a dischargespout 43 projecting from the periphery, is fitted, at bothv vend faces, with trunnions 63, 64 journalled each in one of the bearings 60aiid 61, in such a manner that the quern case may rotatein said bearings. VAny not intended rotation of f the quern case is prevented by means of two 'springs 76 and 66, Fig. 5, which are each pushed over an end of a lug 67 provided on the 'inner side'of one ofthe bearings 61, and a stop` 68 on the quern case in close proximity with the said lug. The outer end ofeach spring rests against the Washer 69 which is attached to the bolt ends by means of nuts 70, and the inner ends of the springs 76 and 66 bear against the stop 68 and the lug 67, respectively, suitable pressure blocks 71 being inserted between the latter and the spring ends.

As appears from Fig. 5, the bore in the lug 67 through which the bolt 72 passes is flaring, so that said bolt may oscillate .in the lug 67 when the quern case is rotated in the direction indicated by the arrow in F ig.' '5. yThe quern shaft 7 is journalled, in both of the truiinions 63 and 64,r in ball bearings 65, one of which is provided in each of the said trunnions. The springl 10 pressing the. rotary grinding body against the material'between the grinding surfaces is disposed inside of the trunnion 63 and encircles the portion of the shaft 7 which is situated between the grinding body 9 and the ball bearing 65 in the said trunnion. n

Thevother end of the quern shaft projects into the trunnion 64 and is supported there as mentioned aboveby a ball bearing 65, and the shaft itself supports the eccentric sleeve 11 serving to move the operating rod 17 of the shaking tray 15. The last mentioned end of the shaft 7 is further provided with a bore is inserted. This ball receives the pressure e 'journalled in the fixed frame' of the quern,

from the end of a threaded spindle 74 which is screwed into a nut 75 and, outside of the said nut supports a hand wheel 77. The nutV posite pins 78, a ring encircling the outer end'of the trunni'on V64a1`id pivotedmon a pin l *i 81 in the lug 82 on the bearing 61. The ring i' 80 isfattached, at one point of its periphery, to the pin'64 by means of a screw 83. 84'is a wing nut serving as check-nut for the nut 7 5%? and securing the'spindle 74'iinmovably in the latter. v f c Y ln'this construction also, the shaking tray exactly to the cam member 50 in Fig. 2, but i 'is here attached to a collar 86 which ylimits lthe supply opening 6.

The top face of the 15 is pivoted about a pin 16 on the` feeding liopperl, the supporting Vbrackets 14 of" tappet^85 rests against a' projection 51V on the bottom side of the shaking tray 15.

I 'Byloosening the nut 84 and turning the hand wheel 77, the'shaft 7 maybe displaced longitudinally against the action vof the spring 16, whereby the grinding body 9 will vbe moved away from the grinding body 4,` so that it will be practicable toL adjust the i grinding bodies to any desired clearance An automatic adgustinent of the Vload on ,latter will rotate'in'th'e direction indicated by the arrow in Fig. 5, and the springs 66 and 76 will thereby be compressed. Due to this rotation vthe pin 78 on the nut 7 5 will* move upward in. the sloping slot 7 9, as indithe quei-nis effected in the following nianj cated by the arrow in Fig. 4, and thereby thek vnut 75 and consequently the threaded spindle 74 will be pushed inward into the trunnion 64, in such anianner lthat the shaft 7 will be displaced and will pull the grind- Y ing body 9 away from the grinding body 4.

The rotation of the quern case will, at `the same time, cause thetappet 85 tol lift the shaking tray in suoli a manner that the latter ceases to be actuated by the rod 17 during as mentioned above.

If preferred, there ymay be used, instead ofy the spring device comprising parts 66-72,

a devicelike the one shown in Figs. 1-'3 for preventing the rotation of the quernt case,

and inA general the above described "details of the first construction maybe Vapplied directly Vto the modified V'ccinstru'ctiong `withoutthe scope fof vthe continued rotation ofthe shaft 7, where- `by the supplyof grain willbegreatly reduced K4iis e In both constructions the quern case is and the quern shaft is Vjournalled in the quern`V "ies y journal the shaft 7 in the bearings90 ona base or bed 91, there being then inserted between the quern case 2, and the base 91 aresilient device 92of-any suitable construction tary grinding body 9" as indicated by the arrow in F ig. 8. The` spring 10 may be inyserted, forinstance, between a ring 93 fixed on the shaft 7 and the ring 27V resting against the central portion 28 l(Fig. 1) ofthe arm 29.

f5"3 In the construction shownin Fig. 8 the guidingrails, 39may be disposed'at any suitable ypoint ofthe quern base 91.

Having now particularly described 'and A ascertained the naturejof my said invention and iny what manner the same is to be per-` formed, Ideclare that what I claimlis 1. A: quern comprising a quern shaft, a.

quernicase arrangedto -revolve about the axis Hof the quern, a grindingbody attached tor 25' the quern case, a grinding body facing the first .one aand attached to the quern shaft to 'be rotated by thefsame, means to prevent4 rotationvr of the quern' case untilthe load on n the quernfexceeds a permissible limit and to,

30"'al1owthequern'case to perform a rotary v.motion in the direction of motion ofthe quern.y shaft consequent Aupon the' friction which,y

during an overload arises between the mate-A .-rialto be ground and the grinding'bodies,

and means wherebyV thequern case,on beingv rotated, spaces the grinding bodies fromy each other. n Y 1 2.1A querny comprising a quern shaft', a

-quern case arranged to revolve about the axis 40'"of the quern, agrindingbody attached to the quern case, ay grinding body facingthe first one and vattached to the quern shaft to be rotated bythe same, a-,feeding device disposed above a. supply openingv in the quernv case,

"means *operated` by the quernshaft during itsrotation for oscillating the feeding device, means` to prevent rotation of the-quern caseuntil the load on the quern exceeds a A .permissible' limit andto allow vthe quern case v""t0'fperform a rotary motion in the direction of motion of the quern shaft-consequentupon thee vf riction which, 'during an overload, arises between the material to be ground .f @and the grinding bodies, means whereby the .55"quern case, on being rotated, )spaces the grinding bodies from each other, andmeansf whereby the quern case simultaneously effects Y such a relative displacement betweenl the feeding device andthe means for oscillating it that the vsupply of material fed to the quern case will be reduced.l

` 3. A quern comprising a quern case, a quern shaft journalled in the quern case, a frame iny which the quernY case -is journalled co-axially 5 with the quern shaft, a grinding body at- In such case the rotation.

tachedy to the quern case, a grinding body facing .the first one and attached to the quern shaft to be rotated ,by the same, a feeding device disposed above a supply opening in the quern case, means operated by the quern shaft during itsv rotation for oscillating the feeding device, means to prevent rotation of the quern case until. the load on the quern exceeds a permissible limit and to allow the quern case to perform a rotary motion in the direction of` motion of the quern shaft consequent. upon the friction which, during an overload arises between the material to be ground and the grinding bodies, means whereby the quernv case, on being rotated,

spaces the grinding bodies from each other, L

and means whereby the quern case simultaneously effects such a relative displacement betweenthe feeding means for oscillating it that the supply of material fed to kthe quern case will beVv reduced.

4. A quern comprising a quern case, a quern 'shaft journalled in the quern case, a frame in which the quern case is journalled co-axially with they quern shaft, a grinding body at-4 tached to the quern case, a grinding body p facing the first one and attached to the quern.

shaft to be rotated by thefsame, a feeding device which is disposed above a supply opening inthe quern casey and directs material thereto, 'means for actuating said feeding device, means connecting the said frame to thequern caseand preventing rotation'of the latter until the. load onthe quern exceeds la permissible limit, said means allowingv the quern case to perform a'rotarymotion inl the` direction of motion'of the quern shaft consequent upon the friction which, during an overload, arises between the material to be ground and the grinding bodies, means whereby the quern case, on being rotated.v spaces the grinding bodies from one another, y

and means whereby the quern case simultaneously' effects such a relative displacement between the feedingcdevice and itsy actuating means that the supply of material fed to the quern case will be reduced.

5. A quern comprising a quern case, a quern shaft j ournalled in the quern case, a frame in which the latter is journalled, a grinding body attached in the quern case, a grinding body attached, opposite the first one, to the `quern shaft to be rotated by the same, means for adjusting the distance between the grinding surfaces on theftwo grinding bodies, a feeding device whichl is disposed above a supply opening in the quern case and directs material thereto, means for actuating `said feeding device, means connecting the said frame to the quern case and preventing rotation of the latterk until the load on the quern exceeds a permissible limit, said means allowing the quern case to perform a rotary motion in the direction of' motion of the quern shaft consequent upon the friction which, during an overload, larises between the material to be ground and the grinding bodies',-means whereby Ythe quern case,l on beingl rotated, spaces the grinding bodies from each other, and means wherebyl the quern case simultaneously effects sucha relative displacement between the feeding device and its actuating means that the supply of material fed to the quern case will be reduced.

6. A quern comprising a quern case, a que-rn shaft journalled in the quern case, a framein which the'quern case is journalled co-arially with the quern shaft, va grinding body attached to the quern case, a grinding body attached, opposite the first one,'to the quern shaft to be rotated by the saine," a spring maintaining the rotary grinding body pressed against the Lmaterial to be ground-between the grinding surfaces of the two bodies, means foradjusting the distance ,betweenthe two grinding surfaces against the` pressure of the said spring, a feeding device kwhichis disposed above asupply opening in the quern caseaii'd directs material thereto, meansl for actuating said feeding device, means connectingthesaid frame to the 'quernfcase and preventing rotation of thek quern case until'nthe loadoii ithe yquern exceeds a permissib-le limit,

saidY means allowing the quern case to performV arotary motion in the direction of Ymotion of the quern shaft consequent upon'the friction which,`during an overload, arises between n the materialto be ground andV the grinding' bodies,"meansfwhereby the quern case, on being rotated, pspaces the grindingbo'dies from each other, and means by which the quern case simultaneously eiectsf such' aV relative fdisplacement VVbetween thefeeding device and itsl actuating rmeans vthat the supply of material fed to the quern case will be reduced.

7'.' A quern'comprising a quern case, a quern shaft jouri'ialled inthe que'rn case, av framein which' the quern ca'seis journalledi, resilient means connecting the quern case with the frame and vpreventing rotation of the quern case so longfas the load on the quern does noty exceed a certain limit, aA grinding body l.fined in the quern case, a grinding body attached toV thequern shaft to be rotated by the same,

a spring maintaining the last mentionedr8. `Aoluern comprising a quern case, a quern' shaftfjournalled in the quern case, frame in` which the quern case is journalled, resilient means connecting, the quern case withr the frame and preventing rotation ofthe'quern case so long as the loaden thequern does not exceed a certain limit,`a grinding body which is attachedto thel uern case a Grindinobod f attached to the kquern yshaft'and rotated'by the same, a' spring maintaining the last men-v tioned grinding body pressed resiliently against the material to be ground, means to Y adjust the distance between the grinding sur-V faces against the pressure of the said spring,

said adjusting means beingactuated b y the quern case, when the latter rotates, in such; a manner that the said means push onegrind-V ing body away from'the other one, whereby the quern is relieved; a'feeding device, means moved bythe quern shaft and imparting an oscillatory motion to the feeding device, and

a ycam on the quern .case which, during a rotation of the quern case, moves the feeding device away from its actuatingineans, whereby the supply offgrain fed tothe'quern case will be reduced. Y H V i i 9. A quern comprising a quern case,'aquerny shaft journalled in the querncase, a y.frame in which the quern case is Journalled, resilient means connecting the quern case to the frame and vcoim'teracting.afrotation of said case, a grinding body which is attached' to the quern case, a grinding bodyy attached tothe `quern shaft andi rotated by the same, a spring which maintains the rotary grinding body pressed resiliently against Vthe material to be groundv lb'ctween'the grinding surfaces, a body 'atl tached a'djustably tothe quern case and serving to transmit the pressure of the said spring to the quernshaft, a stop for the said body providedon the frame of the quern case; said body and said stop havingcoacting sloping sof Y contact ysurfaces to cause the s'aid'body and,

hence, the quern shaft and the grinding ,body

attached thereto to move vaxially kwhentheY quern case, by itsrotatioin, moves the saidbody along the/said stop; a feeding device,

means actuated bythe quernfshaft for imwV parting an oscillatory motion to the feeding device, and a cani on'the quern .case which, when the Alatter is rotated in the direction of lrotation of the quern shaft, pushes` thelfeed'- ingdevice away from the means serving to oscillate itwhereby the supply of grain fed to the quern case will' bereduced.

l0. A quern comprising a quern case, a

quern shaftjournalled inthe quern case,a

frame in which the quern case is journalled, resilient meansconnecting the quern case to Vthe frame and counteracting a rotation of said case, a grinding body whichv is attached toy iis,

the quern case, a grinding body attached to v the quern .shaft and rotated the same, a spring which maintains the rotary grinding body pressed resiliently against the material. to be ground between the'gnin'ding surfaces,

'iscA a body attached adjustably to the quern case and serving totransmit the pressure of the said spring to the quern shaft, a stop for the said body provided on the frame of the quernr '5 case; said body and said stop having coacting vsloping surfaces to cause the said body and,

hence, the quern shaft and the grinding body attached thereto to move axially when the quern case, by its rotation, moves the said body along the said stop; a feeding device, means actuated bythe quern shaft for imparting an oscillatory motion to the feeding device, a cam on the quern case which, when the latter is rotated in the direction of rotation yof the quern shaft, pushes the feeding device away from the means serving to oscillateit, whereby the supply of grain fed to the quern case will be reduced, and an arm pivoted to the quern case, one end of said armresting against the frame of the quern case in such a manner that the arm, when rotated, forces ythe ,quern case lto rotate in the frame, whereby the grinding bodies are moved away from each other.

11. A quern comprisingl a quern case,fa quern shaft journalled in the quern case, a frame nwhich the quern case is journalled,

, resilient `means connecting the quern case to p theframe and counteracting a'rotation of the 3oj-sa1d case, a grinding body which is attached yto the quern case, a grinding body attached to ,the quern shaft and rotated by the same, a spring which maintains the rotary grinding body pressed resiliently against the material Y to be ground between the grindingsurfaces, a body attached adjustably to the quern case and'serving to transmit the pressure of the said spring to the quern shaft, a stop for the said body provided on the frame ofthe quern case ,sa-id body and said stop having coacting sloping Contact surfaces to cause the said body and, hence, the querny shaft and the grinding body attached thereto to move axially when the quern case, byvits rotation, moves the said body along the said stop, a box to receive the ground material and to support the frame, a feeding device, means actuated by the quern shaft for imparting an oscillatory motion to f the feeding device, arcam on the quern case which, whenv the lattery is rotated in the direction of rotation of the quern shaft pushes the'feeding device away from the means serving tov oscillate it, whereby the supply of grain fed to the quern case will be reduced, and an arm pivoted to the quern case, one end of said arm resting against the frame of the quern case in suchl a inanner that the arm, when rotated, forces the quern case to rotate in the frame, whereby the grinding bodies are moved away from each other.

12. A quern comprising a quern case, aV

and counteracting a rotation of the latter, a

quern shaft journalled in the said trunnion and projecting into the quern case, a grinding body attached to the quern shaft inside oi the quern case, agrinding body attached to the quern case and facing the first mentioned grinding body, a shoulder on the quern shaft, an'adj ustable arm provided on the quern case, a spring provided in the tiunnion on the quern case and encircling the quern shaft and adapted to exert .an axial resilient pressure which maintains said shoulder in contact with said adjustable arm, so that an adjustment of said arm causes the quern shaft to be displaced axially, whereby the space between the grinding bodies is varied, a stop attached to the said post and resting against one end of the said arm, means whereby the other end of the said arm may be adjusted manually rela tively to the quern case and thereby caused to movein such a manner that it displaces the quern shaftaxially, a shaking tray pivoted to the frame and set into oscillating motion by action of the quern shaft, a cam on the periphery of the quern case adapted to push the shaking tray away fromthe members actuating the same when the quern case is rotated, and an arm pivoted to the quern case and having one end resting against the post, in such ka manner that on rotation of the arm, its said end forces the pivot of the arm on the quern case to `move away from the post and, consequently, the quern case to rotate.

In testimony whereof he aftixes his signature, f

SILIAM BJERRE.

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