US1744299A

US1744299A - del-linger

Info

Publication number: US1744299A
Authority: US
Publication date: 1930-01-21
Anticipated expiration: 1947-01-21

Description

Jan. 21, 1930.

A. M. DELLINGER MILL z Sheets-Sheet 1 Filed Nov. 17, 1928 I N Inrewfor W M 1% Mi m ATTORNEY Jan. 21, 1930. A. M. DELLINGER 1,744,299

MILL,

Filed Nov. 17, 1928 2 Sheets-Sheet 2 Q P Lrcnfor 8' av Q flbrabam liDel/fnacr;

Patented Jan 21, 193i PATENT OFFICE ABRAHAM M. DELLINGER, OF LANCASTER, PENNSYLVANIA MILL Application filed November 17, 1928.

W tion of the two main sections of the casing to N the driving means for said rolls the means for quiclrlyniounting and removing said rolls to a special movable mounting of one of said rolls and to a special ventilating screen and combination thereof with said casing and roll mounting means and to other features as Will more fully be set forth herein.

The t rimary obJects of this invention are to provide in a hinge type casing providing for full access to the hammer rotor and other interior elements a combination of driving means for the feed rolls, two main sections of the casing and hinge means whereby one of said sections may be swung partially about the axis of said hinge means without disturbing the assembly or operation of said driving means for said feed rolls; to provide in combination a pair of feed rolls and casing, in which combination the feed rolls are so mounted that one shall be capable of movement toward and from the other and in which the casing in all operative conditions shall be closed at all points against the discharge of material by the hammer rotor, except at the 5 normal discharge opening; to provide a roll inserted in axially registering slots in said casing and freely held or fitting therein to be at will bodily placed therein and lifted therefrom, in combination. with means sup- CL) porting the ends respectively of the shaft of d roll. slidable endwise of said slots respecl, an d respectively overlapping the adjacent portions of the face of said casing and being in, or substantially in, light contact, or

circngageinent therewith to cover said slots; to

provide a simple sturdy construction whereby the two feed rolls may be quickly removed and replaced when desired for any reason by simply removing their fastening means and to'hrting them out of their respective slots,

Serial No. 320,098.

after first removing the feeding table or chute, and with no occasion to disturb any other parts, or any driving connections or adjustments; to provide perforate means above said rolls for purposes of ventilation and necessary supply of air to the usual discharge and exhaust fan and also to serve as a guard to prevent material being ground from being discharged by the hammers of the rotor during the rapid rotation thereof; to provide an element of said screen mounted for movement with relation to the upper roll and nori'nally fitting closely adjacent theretobut free to move away therefrom to prevent damage to the parts should any vines, hay or other material wrap about the upper roll as sometimes ocours; and to provide a movable guard, preferably moving with such movable screen element, normally fitting against the upper feed roll and extending peripherally thereof sufficiently to prevent any of the material being ground from being carried in the corrugations of said upper roll out through the front of the casing.

In this application I have shown and described only the preferred embodiment of my invention as now manufactured by me simply to illustrate the practice of my said invention as by law required. However, I realize that my invention is capable of other and different embodiments and that the various details thereof are each capable of a great number of different modifications, all without departing from my said invention. Therefore, the drawing and description herein are to be considered as merely illustrative and not as exclusive.

In the accompanying drawings:

Figure 1 represents a side elevation of a mill embodying my invention;

Figure 2, a front elevation thereof, some drive connections being omitted Figure 8, a sectional view on line 3-3 of Fig. 2, some parts being broken away and the rotor omitted;

Figure 4, a fragmentary detail perspective view of the front portions of the

casing sections

1 and 2 adjacent their hinge connection;

Figure 5, a fragmentary detail perspective view of one side portion of the upper casing section 2;

Figure (5, a detail perspective view of certain parts in assembled relation.

Referring now in detail to the drawings 1, designates the lower section of the casing having hinged thereto, or pivotally mounted with relation thereto, a top casing section 2 in which are mounted the driven feed rolls 10 and 11 and feed table or chute 3 entirely independent of section 1 and movable with section 2 about the axis of its hinge or pivotal mounting with relation to section 1.

Said

sections

1 and 2 will together constitute a closed casing, except for the usual discharge through the discharge fan at one side of the bottom of section 1, as indicated in Fig. 2. and the screen covered or guarded air and ventilation intake in the front of the upper part of section 2, as illustrated in Fig. 2, and the adjacent edges of said sections will meet in a dividing line preferably extending in a horizontal plane intersecting the axis of the main drive, or hammer rotor shaft A, as illustrated in Fig. 1.

The main drive shaft A, on which is mounted as usual a hammer rotor, not shown, which may be of any suitable known construction, is mounted in suitable bearings C, such as shown suitably secured in position as by being bolted to eleat plates welded or otherwise suitably secured to the respective side plates of the lower section 1. A drive pulley B is mounted on one end of said shaft A to turn therewith and adapted to be driven by a belt, not shown. leading from a suitable power plant, not shown, all in accordance with usual known practice.

Suitable means will preferably be provided and combined with feed roll power shaft and with fan shaft ll to drive said shafts from main power shaft A and, in general at the desired speeds respectively with relation to the speed of rotation thereof, all in accordance with usual practice in this and similar arts, said means not being illustrated nor described herein as forming no part of the present invention and so far as the present invention concerned it is immaterial. that said shafts 5 and H be driven from main shaft A. but it is to be understood that they fan serving to blow the ground mate :el through its discharge L. A conveyer sit not shown, may be mounted on said shaft H in said trough between said front and rear plates I and the side plates of the lower sec tion 1 to convey the ground material as it collects therein to the discharge fan, and a conveyer pipe or stack. not shown, may be connected to the fan casing L to communicate with the discharge L thereof to receive the ground material as discharged therethrough and convey it to a suitable receiving tank or storage bin under the force of the discharge blast from the fan, both these features being usual appurtenances in this art and their construction, relative arrangen'rent and operation well understood by those working in this art.

The lower section 1 will preferably be mounted on suitable heavy base blocks or beams J as illustrated in Figures 1 and 2.

The shaft 5 extends parallel to shaft A transversely of the lower casing section 1 and is mounted for rotation in suitable bearings 5 supported by the side thereof and is located in the upper and forward portion of said section 1 adjacent the top and front faces r edges thereof or of the side plates thereof, and hinge members or straps of heavy rigid metal rigidly secured to, as by welding, or integral with, the adjacent lower forward portion of the respective side plates of the top casing section 2 extend rigidly from said section 2 on a straight line intersecting the axis of shaft and have perforations in their lower end portions registering in a transverse direction and being concentric with and respectively receiving the corresponding end portions of the said shaft 5, said hinge members 4 respectively being in, or substantially in, free sliding engagement with the respective opposed faces of the side plate of lower section 1 and adapted to turn about the shaft 5 as a fulcrum point and are of the proper length to ensure the proper full contact of the opposed upper and lower edges of the

sections

1 and 2 respectively when the top section 2 is moved to normal closing position, and to give the proper clearance between the upper and lower forward portions of the

sections

1 and 2 respectively when section 2 is being swung about shaft 5 to open or raised position.

A drive pinion or sprocket wheel D is mounted on one end, of shaft 5 to turn therewith and serves to drive a chain E passing about said sprocket D and about idler sprockets F and G mounted on the corresponding side plate of upper section 2 and about and between sprocket wheels or pinions 8 and 9 mounted to turn therewith on the corresponding end portions of shafts 6 and 7 respectively of the respective feed rolls 10 and 11 mounted on said shafts to turn therewith and extending between the opposed inner faces of the side plates of said upper section 2.

Said driving chain E is in the form of an irregular loop and is of such length or size a s to be taut when disposed about said sprockets as above described, and it is important that it shall be kept taut to drive the sprockets 8 and 9 and at the same time it is important that it shall not be put under a leverage that mi ht tend to stretch or break it during the movement of the upper section 2 with regard to the lower section 1. By providing the hinge members or straps 4 of rigid heavy metal rigidly connected with. the upper section 2 and embracing, and extending radially of, the shaft 5, the axes of the pinions D, F,

1 with an upper inverted L-shaped slot comprisin a leg 12 slanting upwardly from front to back and a horizontal arm 12 commun1- eating with leg 12 and extending therefrom thro h the front edge of the plate, as shown in

Fi z

1, 2, 3 and 4, see particularly Fig. 4,

and with an adjacent lower slot 13, the respective slots of each plate registering in a trai'isverse direction with the corresponding slot; of the other plate in the assembled cond' ion of the casing or section 2 thereof.

The respective end portions of shaft 6 of upper rcll 10 in the in unting thereof are fitted in the respective slot arms 12 until they pass into the respective slot legs 12, and in operation are movable upward and downward lengthwise of said slot legs 12 to allow said upper feed roll 1( to move toward and from the relatively fixed rotating lower feed roll 11. Links 14- respectively fitting slidably against the outer faces of the resp ctive side plates of section. and disposed in alignment with the slanting legs 12 of the upper slots serve to cover said leg portions 12 and the rear portions of the arms 12 of said slots respectively to close the casing at these points against the discharge of material being ground, and are formed with bearings rotatably receiving the respective end portions of the shaft 6. The upper end portions of the respective links 1i are pivotally connected by pivot pins 16 to the respective adjacent end portions of the elongated approximately Ushaped yoke 18 straddling, and pivotally mounted on top of, the section 2, a pivot rod 20 passing through registering perforations 20 in the arms .of

said yoke/and through registering perforations in intervening lugs 19 extending from the top portion of section 2 serving to pivotally connect said yoke to said section 2.

A curved handle bar 22 is connected to the rear portion of said yoke 18 to be rigid therewith and extends across and in contact with a vertical rod 21 rigidly mounted on the top of the forward portion of section 2. By manipulating said handle 22 the links 14 may be raised and lowered to cause a corresponding movement of the upper roll 10 to separate the feed rolls to allow of inspection, or removal of an obstruction, or to facilitate the removal of the rolls or for any reason, and a bolt, pin or the like passing through handle lever 22 and cooperating with a series of perforatiens 23 in rod or bar 21 serves as a convenient means for positively holding the upper roll 10 raised in any one of a number of selective raised positions.

Tension helical springs 26, or equivalents, may be provided to normally supplement the action of gravity on the upper roll 10 and its link supporting means for normally holding or pressing said roll 10 toward lower roll 11 and to this end may be hooked respectively through perforations 20 in the respective arms of the yoke 18 and have their lower ends secured by studs or equivalents ri idly projecting from the respective sides of the upper casing section 2.

The respective end portions of the'lower feed roll shaft 7 fit in the respective slots 13 in the respective sides of upper casing section 2 and are mounted in the respective hearing members or plates 15 in assembled relation held to the respective opposed inner faces of said side plates in alignment with said slots 13 by any suitable preferably removable fas tening means, such as bolts 17 passing respectively through perforations 17 in the respective side plates of said section 2, and may work in corresponding registering internally screwthreaded bores in the respective bearing plates 15, or may receive cooperating nuts, not shown. A covering plate M will preferably be provided concentric with the outer portion of the roll 11 as operatively mounted to cover the transverse opening through which said roll is inserted, and said cover will be removably secured in place as by small screws m passing through the respective end portions of said plate M into registering internally screw threaded bores in said bearing plates 15 respectively.

To permit air to be drawn through the upper part of the casing above the feed rolls and down through the material being ground to cool the same and to reduce the discharge of dust and provide for the free running of the discharge fan while preventing the forward discharge of particles under the impact and propulsion of the hammers, not shown, of the usual. rotor, not shown, I provide a perforated panel comprised of an upper sec tion 27 and a lower section 28 and being arranged in a generally vertical position incline-d upward and backward from the upper roll 10 to the opposed inner or lower face of the top of casing section 2 and in general lying in an axially extending plane parallel to a similar plane intersecting the axes of both of the feed rolls 10 and 11.

The

sections

27 and 28 of said panel may be of strong wire screen fabric, or of sheet metal formed with a multitude of closely adjacent small perforations, or of any material suitable to the purpose. If of screen wire construction they will preferably have for each section a sheet metal marginal frame, as well illustrated in Fig. 6. The upper section 27 will preferably be rigidly held immovably in place by any suitable means and may even be welded in position in the section To permit the necessary movement of the lower screen section 28 slidably in contact with and parallel to the upper section 27 of the screen to permit the upper roll 10 to move away from the roll 11 and to maintain the closure between the top of upper roll 10 and the top of the casing section 2, I form guide flanges 33 on or rigidly secured to the respective inner faces of the respective sides of the section 2 in spaced relation to, and parallel with the upper screen member or section 27 and form the sides of the marginal frame of the lower section 28 as flanges 32 respectively fitting in freely sliding guided relation between the respective guide flanges 33 and the parallel spaced respective side portions of the marginal frame of the upper screen section 27 and to yieldingly hold said lower screen section 28 toward said upper roll 10 helical tension springs 35 may be secured to studs 36 immovably mounted respectively in the side plates or on the side plates of the section 2 at appropriate points and hooked about or to the top frame bar 34 of lower screen section 28 or in eyes 34 thereof and tend to pull said lower sliding screen section 28 toward the upper roll 10.

In order that the lower screen section 28 may move relatively toward and from the upper roll 10 in the plane of the screen panel as a whole and cooperate with the link supporting means 14 of said roll to prevent the tendency of the lower portions thereof to spread apart, I provide a rod 29 extending parallel to the axis of roll 10 and through snug fitting circular perforations in the flanges 32, through the legs 12 of the L-shaped upper slots in the respective sides of the casing 2. and through elongated slots 30 in the portions of said links 14 overlying said legs 12 and may have one end headed and receive a nut on its other end to function as a tie rod to hold said links 14 parallel and in free sliding contact with the respective outer faces of the sides of easing section 2, and to function as a stop means preventing relative movement of the lower screen section 28 away from the roll 10 beyond the point where the respective end portions of said rod 29 strike against the 'alls of the respective slots 30. This construction permits the lower section 28 of the screen to automatically adjust its position to prevent damage to it in case some materials being fed in by the rolls 10 and 11, such as hay, vines etc. should wrap about the upper roll 10, as sometimes happens, allowing the section 28 with its concave foot 31 to move away from the roll 10 a distance sufficient to compensate for the thickness of material thus interposed between said foot 31 and the face of roll 10.

In order to prevent any material partially ground being carried around in the pockets or corrugations of the upper roll 10 I provide a concave foot member 31 constituting the lower horizontal bar of the marginal frame of the lower screen section 28, said foot member 31 extending axially of the roll 10 for the full length thereof as illustrated in Fig. 6 and eYtendiL peripherally rcarwardly beyond a line perpendicular to the screen and intersecting the axis of roll 10, as illustrated in Fig. 3, or, in other words, extending suflicicntly to cover the concave pockets of the roll 10 before any portion thereof mores about the axis of the roll to the point where it could serve to re n par ially ground material thrown against said roll it) by the hammers of the rotor.

The incl ned bottom of the feedingtable or chrte 3 will er; oil in an axially extending plane passi between the :uljaccnt portions of the rolls l0 and 11 in their norma relative operative positions and perpend cular to an aiziai'l -i 01 t: plane interse a, the axes of said rolls, to prevent clog 1" the throat or the bridgii' i at this poircorn on the cob or similar bulk materi; ls when placed in the feeding table and still obtain the desired downward inclination to the degree of efliciency desired to facilitate the gravity feed of the material into the throat, or to the feed rolls.

The rear or inner end of the feed table or chute 3 will. have its bottom portion preferably slightly axially concavcd to [it on top of. and be suliportcd by the curved plate M, and will have its side portions 'lormed to overlap the adjacent side portions ot the casing section 2 about and including the arm portions 12 of the upper L-shaped slots to cover the same to cover or close the casing, itsuch points against the discharge of pa les by the impact of the rotor han'nners therethrough.

Any suitable means may be employed for limiting the movt nent of the lower screen sect on 28 with its foot 3i toward the upper feed roll 10 to prevent iric on and undue wear of t foot 3 ,v and to this end the lower end alls oi the slots 30 may he so positioned as to coo ate vi, the tie rod 29 in pre.ent-- ing the loot :1 from an v engaging the eriphcral face of said roll 1. 1, all as shown in The throngln feed t; we or chute 8 may be removably ecur-ed in N by any suitable means, such as bolt, 3" passing through perfo czioirs in the respective sides of said table or chute 3 and registering with corresponding perforations 3 in the respective side plates of the upper casing section 2 and respectively receiving cooperating nuts, in accordance with usual practice.

The lower end walls of the legs 12 of the respective L-shaped slots may serve, as illustrated, as means limiting the downward movement of the upper roll 10 toward roll 11, but this is not essential and any other usual stop means for this function may be employed if desired.

To remove the rolls it suffices to merely re move the bolts 3, remove the feed table 3, remove the tie rod 29, and remove the pivot pins 16 to permit upper roll 10 to be freely lifted out and replaced, and, to remove lower roll 11 after the chute or feed table 3 has been removed it is merely necessary to remove the bolts or screws 17, when said feed roll 11, with its bearings 15 and cover plate M may all be lifted out together and thereafter separated, if desired, by the removal of the small cover holding screws m.

Any suitable material may be used for any part.

Suitable latch or locking means for locking the upper section 2 of the casing against movement about the shaft 5 with relation to the lower section 1 will preferably be provided and may comprise a slotted horizontally extending plate N welded or rigidly secured to the upper section 2 and a pivotally mounted latch O mounted in the lower section 1 in such position that when the two sections are in normal position and the latch is moved about its pivotal point its stem will lie in the notch of plate N and its enlarged head will overlie the portion of said plate N adjacent to said slot thereof.

Of course the usual perforated screen plate P will be arranged in the casing concentric with the hammer rotor and between the same and the fan shaft H as indicated in dotted lines in Fig. 1.

Having thus described my lnvention, what I claim as new and desire to secure by United States Letters Patent is:

1. A casing comprising an upper section and a lower section, a drive wheel mounted for rotation about an axis permanently fixed with relation to said lower section, a plurality of wheels several of which are mounted for rotation about axes permanently fixed with relation to said upper section and to each other, and one of which is movable with its axis parallel to the axes of all the rest of said wheels including said drive wheel, and means extending about and engaging all of said wheels for driving said driven wheels from said drive wheel, in combination with rigid means rigidly connected with said upper section and mounted for partial rotary swinging movement about the axis of said drive wheel for swinging movement of the upper section, with said driven wheels, with relation to the lower section without disturbing the operative connection between said driven and said drive wheels.

2. A casing comprising an upper section and a lower section, a drive wheel mounted for rotation about an axis permanently fixed with relation to said lower section, a plurality oi. driven wheels several of which are mounted for rotation about axes permanently lined with relation to said upper section and to each other, and one of which is movable with its axis parallel to all the rest of said wheels including said drive wheel, and flexible taut belt means extending about and engaging all of said wheels for driving said driven wheels from said drive wheel, in combination with rigid means rigidly connected with said upper section and mounted for partial rotary swinging movement about the axis of said drive wheel for swinging movement of the upper section, with said driven wheels, with relation to the lower section without disturbing said flexible driving means or its driving engagement with all of said wheels.

3. A casing comprising an upper section and a lower section, a drive shaft mounted in said lower section for rotation about a fixed axis, a drive wheel mounted on said drive shaft, a pair of feed rolls mounted for rotation in said upper section, driven wheels respectively connected to the respective feed rolls to turn therewith about their respective axes, and flexible means driven by said drive wheel for driving said driven wheels, in combination with rigid hinge members rigidly connected with said upper section and mounted on said drive shaft for turning movement about the axis thereof, whereby said upper section with said driven rolls may be moved about said shaft with relation to said lower section without disturbing the relation between said drive and driven wheels and the flexible driving means.

4. A casing comprising two sections, a main drive shaft extending through overlapping parts rigid with said sections respective ly whereby said shaft serves as a pivot for relative movement between said sections, and a drive wheel mounted on said shaft to rotate about the axis thereof, in combination with a plurality of driven wheels mounted for retation on shafts mounted in one of said sections, and operativeiy taut flexible driving means passing about and engaging said drive and driven wheels, said driven wheels and their respective shafts being movable with the section in which they are mounted about the axis of said main shaft without disturbing the flexible driving means or its engagement with said wheels and without disturbing the relation between said drive and driven wheels.

5. A mill comprising a casing, and a pair of feed rolls mounted in parallel relation in adjacency in cooperating relation, one of said rolls being movable in parallel relation, toward and from the other and having a shaft which extends through the respective sides of said casing, the respective sides of said cas ing being slotted to receive the respective end portions of said shaft and permit the necessary movement thereof, in combination with parts receiving and supporting the respective end portions of said shaft, movable therewith in sliding contact with the outer faces of the respective sides of said casing, and respectively overlapping the portions of said sides adjacent the respective slots and extending across the latter to close the casing at such points against the discharge therethrough of material under the impulse of the mill mechanism.

6. A feed mill comprising a casing comprising side plates respectively havmg an upper L-shaped slot and a lower slot, said slots extending through the front edges of their respective side plates and said slots of one plate being transversely aligned with the correspondin slots of the other plate, in combination with a rotary upper feed roll having shaft end portions respectively received in the upper L-shaped slots and mounted for movement lengthwise of said slots, a lower feed roll having shaft end portions respectively received in the lower slots, removable means for supporting said rolls for rotation in cooperating relation with each other in their respective slots, and a feed table removably secured to said casing adjacent to and in front of said feed rolls and normally obstructing their path of movement in their insertion in and removal from the casing, whereby on the removal of said table said feed rolls may be removed from, and replaced in, the casing without disturbing any other art of the mill mechanism and without distur ing the relation between the feed rolls and their shafts respectively.

7. A feed mill comprising a casing, a pair of parallel superposed feed rolls mounted for rotation in said casing to feed material between them into the mill, in combination with a feed table having an inclined bottom disposed at right angles to a radially extending plane intersecting the axes of both of said feed rolls, whereby bridging of the material being fed will be avoided without impeding the movement thereof by gravity toward said feed rolls.

8. In a hammer type feed mill, a casing, a pair of superposed feed rolls rotatably mounted in said casing, the upper feed roll being movable toward and from the lower roll in parallel relation thereto, and a discharge fan, in combination with a perforate front casing closure mounted in said casing above said feed rolls and comprising a section movable with the upper roll of said pair of rolls.

9. In a hammer type feed mill, a casing, a pair of superposed feed rolls rotatably mounted in said casing, the upper feed roll being movable toward and from the lower roll in parallel relation thereto, and a discharge fan, in combination with a perforate front casing closure mounted in said casing above said feed rolls and comprising a section movable with relation to said upper feed. roll.

10. In a hammer type feed mill, a casing, a pair of superposed feed rolls rotatably mounted in said casing, the upper feed roll being automatically movable toward and from the lower roll in parallel relation thereto, and a discharge fan, in combination with a perforate front casing closure mounted in said casing above said feed rolls and comprising a section movable with said upper feed roll and automatically movable with relation to said upper feed roll.

11. In a hammer type feed mill, a casing, a lower feed roll rotatably mounted therein, a rotatable upper feed roll extending in said casing and movable toward and from said lower feed roll in parallel relation thereto, slotted links respectively having bearings receiving and supporting the respective end portions of the upper roll shaft, said links being movable with relation to said casing, in combination with a perforate member disposed in said casing above said 11 :per roll for closing said casing against the discharge of particles being ground and comprising a relatively fixed section and a section movable in sliding relation therewith, and a rod passing through said sliding section and engaging therewith to move therewith in the direction of its sliding movement and extend.- ing through the slots in said links.

12. In a hammer type feed mill, a casing, a lower feed roll rotatably mounted therein, a rotatable upper feed roll extending in said casing and movable toward and from said lower feed roll in parallel relation thereto to cooperate therewith and having shaft end portions respectively extending through the respective sides of the casing, said sides of the casing being slotted to receive said shaft end portions and pcrmi t the movement thereof with relation to said lower roll, in combination with links for rotatably supporting said shaft of said upper roll, movable therewith toward and from the lower roll, and slotted in line with the slots in the sides of said casing, a perforate member disposed in said casing above said upper roll and comprising a relatively fixed section, and a section movable in sliding overlapping relation therewith, and a rod passing through said sliding section and engaging the same to move therewith in the direction of its sliding movement and extending through said slots in the casing and said slots in the links.

13. In a hammer type feed mill, a casing, a lower feed roll rotatably mounted therein, a rotatable upper feed roll extending in said casing and movable toward and from said by through the front of the casing in the oplower feed roll in parallel relation th reto eration of said upper feed roll. to cooperate therewith and having shaft end In testimony whereof, I have signed my portions respectively extending through the name to this specification at Lancaster, respective sides of the casing, said sides of Pennsylvania, this first day of November,

the casing being slotted to receive said shaft 1928. end portions and permit the movement there- ABRAHAM M. DELLINGER. of with relation to said lower roll, in combination with links for rotatably mounting 10 said shaft of said upper roll, movable therewith toward and from the lower roll, and slotted in line with the slots in the sides of said casing, a perforate member disposed in said casing above said upper roll to close the space between said roll and the top of the g0 casing and comprising a relatively fixed section, and a section movable in sliding overlapping relation therewith, a rod passing through said sliding section to move therewith in the direction of sliding movement thereof and extending through the slots in said casing and the slots in said links, and means carried by said rod for engaging the respective outer faces of said links. 25 14. In a hammer type feed mill, a casing,

a lower feed roll rotatably mounted therein, a rotatable upper feed roll extending in said casing and movable toward and from said lower feed roll in parallel relation thereto, 30 and slot-ted links respectively having bearings receiving and supporting the respective end portions of the upper feed roll shaft, in combination with a perforate member disposed in said casing above said upper roll 35 for closing said casing against the discharge of particles being ground and comprising a relatively fixed section and a section movable in sliding overlapping relation therewith, a rod passing through said sliding section and 40 engaging therewith to move therewith in the direction of its sliding movement and extending through the slots in said links to limit the sliding movement of said movable section with relation to said upper feed roll, 45 and a concave axially extending guard carried by said sliding section and normally di posed adjacent to said upper feed roll and extending peripherally rearwardly about said upper feed roll to cover said upper feed 50 roll and prevent the escape at such point of material thrown by the hammers of the hammer rotor of the mill.

15. In a hammer type feed mill, a casing, a pair of superposed feed rolls and means for rotating said feed rolls in opposite directions to draw between them the material to be ground and discharge it in said casing, and a concave axially extending guard normally disposed closely adjacent the upper feed roll 50 and extending peripherally about the same to such extent as to prevent any material thrown by the hammers of the rotor striking against the upper feed roll at such point with relation to its axis and contour of its 7 face as to lodge thereon and be carried there-