US2505023A

US2505023A - Rotary beater grinding mill

Info

Publication number: US2505023A
Application number: US564929A
Authority: US
Inventors: John W Williamson
Original assignee: ROBERTS MILL Manufacturing Co
Current assignee: ROBERTS MILL Manufacturing Co
Priority date: 1944-11-24
Filing date: 1944-11-24
Publication date: 1950-04-25
Anticipated expiration: 1967-04-25

Description

pr 1950 J. w. WILLIAMSON 2,505,023

ROTARY BEATER GRINDING MILL Filed Nov. 24, 1944 2 Sheets-Sheet 1 JOHN W YVELIAM S ON IN VEN TOR.

ATTORJVE Y J. W. WILLIAMSON ROTARY BEATER GRINDING MILL April 25, r950 Filed Nov. 24, 1944 2 Sheets-Sheet 2 JOIIIV w WILLMMSON 4 INVENTOR.

ATTORNEY Patented Apr. 25, 1950 no'mnr nm'rsa GRINDING MILL John w. Williamson, Los'Angeles, CallL, surmito The Roberts Mill Manufacturing Company, Denver, Colo., a corporation of Colorado J AppllcationNovem b'er 24, 1944, Serial No. 564,929

Y (cum-s1) This invention rela'es to grindingor comminuting mills or machines, and, more particularly, to, grinding mills of the hammer mill type.

Grinding mills of the hammer mill type are used extensively in producing comminuted material from forage such as hay, grain, orthe like,

to produce stock feed, the comminuted material being mixed with molasses or other highly nutritious products-' to provide an enriched, feed.-.

To insure 'a more thorough mixture'of the molasses or enrichment with the comminuted forage, the hay or grain. product is preferably reduced to a relatively uniform small size. In a hammer mill, forage such as hay is fed by a moving belt into' a comminuting section in which a plurality of grinding elements are mounted about the periphery of a cylindrical framework, and coact with an eccentric screen to cut up or grind the hay to produce particles sufficiently small to pass. through the holes in the screen. However, "due to varying degrees of, toughness occa- -sioned by type, quantity or moisture content of the hay, and also due to variation in length and/ or size of individual stalks, the load imposed on the machine as well as the grinding requirements tend to vary considerably over a short space of time. There is a tendency for ground or unground material to collect about shafts, adjacent the point 'at which such shafts pass through the housing of the machine, and also to collect within the cylinder, or cylindrical framework carrying the grinding elements. Such collection of material, when dry, constitutes a serious fire hazard, due to spontaneous combustion or ignition by heat developed through friction of moving parts. Furthermore, the

screens tend to clog at times, due not only to variations in the amount of comminuted material produced, but also due to inadequacy, on certain occasions, of conveyance of the comminuted product from the screen.

Among the objects of this invention are to pro- J vide a grinding mill which will readily accommodate material of variable toughness. length or size, or resistance to maceration or comminution; to provide such a mill, particularly of the hammer mill type, through which the material is conveyed eifectively and efliciently; to provide such a mill which will readily accommodate variations in feeding rate; to provide such a mill in which the fire hazard is minimized; to provide such a mill in which feeding may be stopped quickly by the operator in case of apparent clogging of any remaining portion of the mill; to'provide such a mill in which rotating parts are driven by a noveltypelof drive: to provide a grinding mill of the hammer mill type which includes .a'novel grinding-element; to provide such a ,milllwhich-includes a novel device adapted to feed the material to the grinding element; to provide such a mill in which the construction and general arrangement of parts are such that more uniform grinding results may be obtained; to provide sucha mill which is particularly adapted to grindliay or. similar fibrous feed, but which may readily be adapted to grind grain and similar material;- and to provide a grinding mill, particularly of thehammer mill type, which is relatively simple in construction, and is durable and efiicient in operation. Additional objects and the novel features of this invention will become apparent from the description which follows.

In general, a grinding mill constructed in accordancewith thisinvention may include a preliminary feeding device by which hay or other fibrous material may be supplied to a'combined chopping andfeeding device adapted to reduce the fibers to a more uniform length through the combined action of two sets of knife-carrying elements, the knives .orblades of one element preferably being in longitudinally staggered relation withrespect to the 'knives of the other element and mounted for'rotation in the same direction so as to exert a combined chopping and feeding action on the material. and feeding device supplies material to a grinding device which may include a cylindrical framework carrying about its periphery a plurality of grinding elements adapted to cooperate with an eccentric screen through the apertures of which the comminuted material'passes when reduced to the desired size. The comminuted material passes through the screen into a receiving chamber from which it is drawn by the suction eiIect produced by a blower or the like, and into which receiving chamber an adjustable amount of air may be supplied for scavenging purposes and also for regulating the suction effect and consequent rate of withdrawal of comminuted material. The grinding cylinder is preferably so constructed that adequate circulation of air within the same and also at the ends of the grinding space provides feed to the grinding elements and also reduces the tendency for material to pile up at any given point, thus minimizing the fire hazard.

Apparatus embodying the above features is exemplified by that illustrated in the accompanying as drawings. in which:

The chopping Fig. l is an end elevation of such apparatus; Fig. 2 is a top plan view of the apparatus of Fig. 1, partly broken away to show the interior construction;

the housing H is removed and transferred to a further point of use or treatment by su table means which includes a blower 13, preferably of the centrifugal type.

As in Figs. 2 and 3, installed within the housing H are a combined feeding and chopping device which includes two knife elements Kl and K2, which rotate in the same direction, that indicated by the arrows of Fig. 3. The knives of one element are disposed in longitudinally staggered relation with respect to the knives of the other element and both knife sets rotate in the same direction so that fibrous material, such as hay or the like, not only is chopped into more uniform lengths but is moved toward a grinding section or device. The grinding device includes a cylinder C and an eccentric screen S which extends a substantial distance around the periphery of cylinder C. The comminuted material, when ground to' the desired size, passes through the apertures in screen 8 into a receiving chamber R, from whence it is drawn by the suction effect produced by blower B and transferred to a point of subsequent use or treatment. To insure that the comminuted material will be effectively removed, scavenging and regulatory air may be supplied to the bottom of the receiving chamber R through an adjustable air duct D. The air supplied through duct D assists, rather than impedes, the passage of material through screen 8, since it tends to insure that material falling toward the bottom of the receiving chamber will be removed through exhaust opening or outlet 0, and will not pile up in the rear half of the chamber and thereby clog the passage of material through the major portion of the screen. Also, the suction effect on the screen can be regulated by adjustment of the amount of air supplied through duct D.

When it is desired to perform the grinding operation only, as in the case of grain or other material of relatively small and more uniform size, the feeding mechanism F and combined feeding and chopping device, which includes knife elements Kl and K2, may be stopped in a manner set forth in detail later, and the grain or similar material fed directly to the grinding device through a grain spout or hopper G, as in Fig. 3.

The feeding mechanism F may comprise a plural ty of endless belts Ill having afilxed thereto a plurality of spaced, transverse cleats I l adapted to move material along a floor plate [2 extending between sides I 3, which with floor plate l2 form a trough or chute. Endless belts in pass around a driving roller l4 at one end and an idler roller I! at the opposite end, the former be n mounted for rotation in fixed bearings l6 and the latter in adjustable bearings IT, as in Fig. 1. The reduced ends or shaft extensions of rollers l4 and I5, which are mounted in the bearings, may be armed integrally with the rollers, or by welding 4 short sections of shafting thereto, or in any other suitable manner. As in Fig. 2. one end of roller It may be provided with a shaft extension I8 on 1 which is rotatably mounted a gear is to which is attached one side of a law clutch 20, the opposite side of the jaw clutch being keyed to shaft extension 16. The Jaw clutch is operable by a lever 2|, one end of which is pivoted on an arm 22, in turn attached to housing H in any suitable manner, as by welding. Gear I9 is rotated by a pinion 23 which is mounted on the outward end of a shaft 25, upon which is mounted the rear knife element K2.

The knife element K2 may comprise a plurality of cutting blades 26 spaced about the periphery of longitudinally spaced discs or plates 21, the cutting blades 26 being attached to the discs in a suitable manner, as by riveting or bolting, so as to be removable for replacement. Discs 21 may be equally spaced longitudinally along a cylinder 28 attached at its ends to shaft 25. Similarly, the knife element Kl may comprise a plurality of blades 29 disposed in sets and equally spaced about the periphery of longitudinally spaced discs 36, in turn attached to a cylinder 3| secured at its ends to a shaft 32. Discs 30 may be slightly larger than discs 21 in order more effectively to reduce in size lumps or larger masses of material fed to the combined chopping and feeding device, while the knife element K2 may be driven at a greater speed'than the knife ele' ment Kl, as by a chain 33 running over a smaller sprocket 34 keyed to shaft 32 and a larger sprocket 35 keyed to shaft 25, as in Fig. 1. By such arrangement, the knife elements Kl and K2 cooperate together to tear apart and chop up masses of forage or the like supplied by feeding mechanism F.

The cutting edges of blades 2-6 and 29 are preferably curved so that a downward cutting action is obtained when the knives first encounter the mass of forage, and so that the cut materia1 will readily drop off the knives as they pass upwardly on the other side of the shaft, with the knif elements rotating in the direction of the arrows of Fig. 3. As will be evident from Figs. 2 and 3. any material tending to be carried upwardly by blades 29 on the rear side of the knife element K-i will be engaged by blades 26 and further out and removed from the knife element K--l At the same time, blades 26 tend to push the cut material into the feed opening for the grinding device, between roller l4 and a reinforcing bar 36, which forms a portion of housing H.

Housing H, within a, portion of which the knife elements Kl and K2 are installed, includes a top plate or sheathing 31 which slopes downwardly over the knife elements K--l and K2 to reinforcing bar 36, to which the upper end of screen S is attached. Housing H also incudes sides 38, on which are mounted bearings 39 for

shafts

25 and 32 of the knife elements. In addition, a hinged door 40 restricts passage of forage to an opening II and regulates feed of forage to the combined feeding and chopping device, but may be moved upwardly for inspecting or replacing parts such as

blades

26 and 29, or for rectifying a clogged condition or the like.

The housing H further includes a semi-cylindrical sheathing 42 which extends, in spaced relation to screen S, from reinforcing bar 36 to a lower bar 43. Screen S extends from bar 36, directly above cylinder C, around the cylinder to a rame bar 44, directly in front of the cylinder C. Screen S is mounted in an eccentric position with R is formed around the screen 8, the rear portion of the space being formed between the screen and cylindrical sh a hing 42, while the forward portion of the exhaust chamber is formed by a front plate 48 and a floor plate 41. In addition,

the ends of the grinding section are closed by side 38 of the housing and a casting 48, which forms a bed for the machine and provides a support and mounting for various parts thereof, as well as closing the ends of recei ing chamber R.

comminuted material discharged into chamber R is removed by the action of blower B, through exhaust opening or out et 0. the blower brine connected with the exhaust opening by a duct 5|.

Preferably the cross-sectional area of exhaust opening is the same as the cross-sectional area of the suction inlet of blower B. This produces a more equalized suction eifect at the outlet 0 and minimizes the tendency of blower B to b come clogged. From the blower B, the comminuted material is delivered through a duct to storage or a point of further treatment or use at which. for instance, molasses or the like'may be mixed if itg the comminuted forage to produce stock.

Air duct D may be formed by an exterior plate 52 extending substantially parallel to the lower portion of sheathing 42, as in Fig. 3, to a channel 53 to which plate 52 and floor plate 41 are attached. The upper nd of air duct D is provided with a hinged door 54 which maybe placedin any desired position to regulate the amount of air drawn through the duct, or shut it 011' chtirely. A feature of the air duct D lies in the fact that it terminates at a point adiacent the bottom of the chamber R, directly opposite the exhaust opening 0, thus causing a current of air to sweep across the bottom of the chamber and insuring that the comminuted material will be removed from the rear portion of the exhaust chamber as well as from the front thereof adjacent the exhaust opening 0. As will be evident from Fig. 3, in the specific construction illustrated in the drawings, when the door 54 is open, comminuted material passing through the rear half of screen S will tend to slide down the sheathing 42 until it is p cked up by the stream I of air issuing'from the air duct D, and there will all times at full capacity and with greater eifectiveness. In addition. by regulating the amount of air drawn through the air duct, the suction effect on screen S and also the rate of withdrawal of comminuted material from the chamber R, which will correspond with the rate of feed to the blower B, may be varied in accordance with the operating conditions or the particular type and /or condition of material involved.

The various parts of the housing may be attached to each other in a suitable manner as by bolts or screws, or parts which will notbe removed for inspection or other purpose may be more permanently attached together as by weld- 6 ing or the like. Preferably, the parts are so put together that access for inspection or similar purposes may be readily had. For instance, for

this purpose, sheathing 42 may be made in two sections, an upper section and a, lower section, each quadri-cylindrical, so that th upper section may be readily removed for inspection purposes or the like.

The grinding cylinder C which carries about its periphery the grinding studs or teeth 45, as stated previously, may include a cylindrical framework mounted on a shaft which is iournaled in bearings 58 mounted on casting 48 of the housing. The framework includes a pair of end discs 51 and one or more central discs 58, the latter being used in larger sizes and omitted in smaller sizes. A plurality of longitudinal bars 59 extend between end discs 51 and are attached thereto in any suitable manner as by welding, bolting or the like, the-bars also being attached to central disc 58 in a similar manner. Longitudinal bars 59 are reinforced by circumferential rings 50, and teeth 45 are bolted to the bars 59. Teeth 45 may be angular in cross section, so that they can be turned to provide a new cutting or macerating edge when the edge previously in use has become worn. With square teeth. as shown, each tooth may be turned to four different edges before replacement orresharpenlng becomes neces ary.

Cylinder C is further constructed so that an adequate c rculation of air therrthrough may be obtained, and also so that material will be effectively removed from points at which it tends to collect, thus reducing any tendency toward clogging and minimiz ng the fire hazard. For this'ournose, each disc may be provided with a plurality of holes 5|, to permit circulation throu h the fr mework, and the framework may be provided with a plurality of longitudinal angles or blades 62, to produce an outward flow of air and spaced about the framework, and preferably secured to those bars 59 which are disposed in the desir d spaced position] The air currents thus produced not only draw material from the interior of the framework but also force material out aga nst the screen S. This assists in the passage of comminuted material throu h the screen, and also assists in feeding mater al out to the teeth 45 and tends to prevent collection of materi l within the framework, thus t nding to eliminate one fire hazard source. Additional fire hazard eliminat on is provided by radially extending vanes or wear plates 63, which are secured to the outside of end discs 51, at spaced points around the periphery thereof. Vanes 63 not only produce radial air currents, but also prevent the casual entrance of material into the space between the end discs 51 and the housing, and further remove by a scraping action material accidentally lodged therein.

The screen S may be constructed in a suitable manner, as of closely spaced woven wire, but it is preferable to utilize a screen which is more resistant to direct thrust and which tends to have a more direct cutting action on the material being comminuted. Thus, as in Figs. 2 and 3, the screen S may comprise a curved plate 64 having a plurality of perforations or apertures 65, and provided with circumferential stiffening bars 66, more effectively to prevent deformation during impact of the material being ground. The upper edge of the screen may be fastened to bar 36 in a suitable manner, as by bolting, while the forward edge of the screen may be similarly fastened to frame bar 44. The grinding snare within s am which the cylinder operates is completed by a plate. 81 which extends upwardly from frame bar 44, and is provided at its upper edge with a lip 68 formed of rubber or other flexible material, the lip being adapted to contact belts l0 and permit passage of cleats ll. Plate 61 and lip I8 merely prevent material from spilling out in front of the apparatus, and are spaced from the ends of teeth 45 a greater distance than the screen S.

A further feature of this invention lies in the drive from motor M to the rotating parts. As in Figs. 1 and 2, the motor M is mounted on a platform I0 secured to casting 48, and drives cylinder C through a plurality of V-belts ll engaging a grooved pulley I2 mounted on the motor shaft and a grooved pulley I3 mounted on shaft 55 of the cylinder C. The cylinder may also be directly driven by the motor, but the knife members K-l' and K--2 and the feeding device F are preferably driven so that an overload on either the feed device or the knife elements will tend to slow these parts of the machine down. but at the same time the grinding section of the machine will continue to operate at full speed, thus insuring an effective and efflcient grinding action at all times. For this purpose, the shaft 55 of cylinder C may be provided with a drive pulley 14 having a plurality of circumferential grooves therein adapted to receive V-belts 15, the V-sides of which engage the grooves in pulley H, but the flat sides of which engage a relatively smooth or flat pulley 18 mounted on shaft 32 of knife element K--l. To maintain tension on V-belts an idler pulley H is mounted on an arm I8, pivotally attached to the housing, and a spring 19 is attached to the housing at one end and to the arm I8 at the opposite end. If desired, the spring may be made adjustable in any suitable manner, as by a rod 80 threaded at the housing end and provided with a lock nut adjustment (not shown).

The action of V-belts 15' is to drive the knife elements K-l and K-2 and also the feeding device F at normal speed as long as the load thereon is normal. However, due to the lesser friction be..ween the flat sides of the V-belts and the relatively smooth pulley II, the driving torque will decrease on an increase in load, so that the speed of the feeding mechanism and the combined feeding and chopping device will decrease upon any sudden increase in load thereon. This will prevent the grinding section of the machine from becoming overloaded due to a sudden influx of material, and will permit the operator to throw lever 2| to disengage clutch 20 and stop the feeding mechanism F, if an excess of feed is the cause of the overload, or to stop the motor M and swing hinged door 40 upwardly to obtain access to the knife elements Kl and K-2 if the difllculty lies in that portion of the machine. Of course, if a slight overload upon the knife elements Kl and K-2 is occasioned by a tougher or more densely packed mass of forage, the decrease in speed will not be appreciable because the feeding device F will not be overloaded and the cutting action of the knives will quickly separate such a mass into smaller pieces-in fact, the action of the knives will usually be found to be more effective against packed or closely matted masses of forage than against a plurality of relatively loose fibers which pass through the machine individually.

After being chopped up into smaller pieces by the knife elements Kl and K-2, the forage 8 passes; through the opening between driving roller I4 and bar 36 to be caught upon teeth and carried against screen S. The teeth 45, which are disposed in staggered relation in adjacent longitudinal rows, tend to macerate and pulverize the material, pushing it against the screen S as the cylinder C revolves. Particles small enough pass through apertures will fall through the screen, and the number of particles so produced will increase as the clearance between the ends of teeth 45 and the screen S decreases. Any material not ground up or comminuted during the first revolution will be carried around and further grinding exerted thereon during subsequent revolution, the material being held against the screen by the outward air currents produced by angles 62, which at the same time tend to remove from the center of the cylinder C any comminuted material which may tend to fall therefrom above. Also, adequate circulation of air within the cylinderis obtained and equalizatiton or air currents provided by holes H in center discs 58 (in case the latter are present). Also, air tends to be sucked outwardly or inwardly through the holes in end discs 51, depending upon the suction eflect produced by angles 62 and radial end vanes 63.

In case grain or similar material having relatively small or uniform size is to be comminuted, the grinding section of the machine alone may be used, as by.removing a section 82 of the housing H to provide an opening through which a plate 83 may be inserted to close ofi the opening between the feeding section and the grinding section. A pair of angles 84 may be provided, so that drain spout or hopper G may be placed over the opening provided by the removal of section 82, and attached to the housing in any suitable manner. Of course, it will be understood that grain may be fed to the grinding section by feeding mechanism F, if desired.

When the grain hopper G is utilized, the tension on idler pulley 11 may be released, and the V-belts taken off the idler pulley and placed in an out of the way position, so that only the grinding section will be driven by the motor M. When forage is again to be treated, the V-belts 11 may be replaced, and operation continued as before.

From the foregoing, it is apparent that apparatus constructed in accordance with this invention is effective and efllcient in operation, includes numerous novel features, which both alone and in combination with other features of the machine are productive of new and improved results, and that the machine is relatively easy to build and simple to operate. It will be understood that, although a particular construction and arrangement of parts has been described, various rearrangements of parts and different modes of construction are possible, without degarting from the spirit and scope of this inven- What is claimed is:

In a grinding mill or the like which includes a housing. adapted to enclose a feeding section and a comminuting section, the combination of a cylindrical framework mounted for rotation in said housing and including a shaft having a disc attached thereto adjacent each end, said discs having holes therethrough; radial vanes attached to said discs on the sides adjacent said housing for inducing a flow of air to remove material from around said shaft between said discs and said housing; a plurality of comminuting studs attached to the periphery of said framework; longitudinal vanes attached to said framework for intit-10D.

ducing a flow of air outwardly from said framework; a screen substantially surrounding said framework and disposed eccentrically thereto, a comminuting space of decreasing cross-sectional area thereby being provided between the periphcry of said framework and said screen, and a cornminuted material receiving space being formed between said screen and said housing; a suction fan; aconduit leading to said suction fan from an outlet in said housing in the lower portion of said receiving space, said outlet having substantially the same cross-sectional area as the inlet of said fan; a partition within said housing and extending downwardly toward the lower portion of said receiving space and terminating beneath said screen and substantially in alignment with said outlet; and an adjustable gate for varying the amount or terminating the air supplied through the space between said housing and par- JOHN W. WILHAMSON.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS