US3912175A - Tub grinder - Google Patents

Abstract

A tub grinder having a rotating side wall and a hammer mill, while a rotor shaft is parallel to but spaced from a radius of the stationary bottom of the tub grinder, so that the swath of cut of the hammers has a width corresponding essentially to a radius of the tub. Economy in manufacture without appreciably affecting performance, as well as a lesser probability of vibration problems, is produced. An outer baffle, spaced from the hammer mill and mounted on the tub bottom, as well as a central inner baffle, assist in guiding hay or the like moving around the tub, into the hammer swath.

Description

[ 51 Oct. 14, 1975 Unite States atent [1 1 Anderson TUB GRINDER Primary ExaminerGranville Y. Custer, Jr.

Attornev, Agent, or FirmHorace B. Van I .RbertR.Andrs ,(l 1,Cl. [75] nvemor o e on me 6y 0 O Valkenburgh; Frank C. Lowe [73] Assignee:

[22] Filed:

Farmhand, Inc., Hopkins, Minn.

Apr. 24, 1974 Appl. No.: 463,442

[57] ABSTRACT A tub grinder having a rotating side wall and a hammer mill, while a rotor shaft is parallel to but spaced from a radius of the stationary bottom of the tub grinder, so that the swath of cut of the hammers has a [52] US. Cl. 241/73; 241/101.7; 241/194 [51] Int.

B02C 13/04 width corresponding essentially to a radius of the tub.

[58] Field of Sear h... 241/73, 101,7, 186 R, 1864, Economy in manufacture without appreciably affect- 241/189 R, 194 ing performance, as well as a lesser probability of vibration problems, is produced. An outer baffle, spaced [56] References Cit d from the hammer mill and mounted on the tub bot- UNITED STATES PATENTS torn, as well as a central inner baffle, assist in guiding hay or the like moving around the tub, into the hammer swath.

Hottmann 241/186 R X Anderson.............................. 241/73 3 Claims, 5 Drawing Figures US. atent 0a. 14, 1975 Sheet 2 of2 3,912,175

m WV WV Q mm TUB GRINDER This invention relates to tub grinders and is an improvement over the tub grinder incorporating an antislug device for hammer mills, disclosed in my prior U.S. Pat. No. 3,743,191 granted July 3, 1973.

The tub grinder of the aforesaid U.S. Pat. No. 3,743,191 includes a tub having a stationary floor and a rotating, circular side wall, with a hammer mill rotor covering substantially a full radius of the floor, being installed in an opening in the bottom wall of the tub structure, which hammer mill rotor extends generally radially from adjacent the axis of the tub structure toward the peripheral, rotating side wall. The rotor consists of a shaft and spaced sets of discs mounted on the shaft, with the hammers being pivotally mounted between adjacent discs, at appropriate positions around the periphery of the rotor. The hammers are adapted to engage hay or the like and hammer or pulverize it while moving around a perforated plate or screen which encircles the lower periphery of the hammer travel. Particles of sufficiently small size drop through holes in the screen and are removed by a conveyor.

The anti-slug device includes a plurality of rigid, plate-like relatively stationary hammer elements or bars which project in generally vertical planes from a mounting plate disposed in spaced position to the hammer mill rotor. The stationary elements extend inwardly to the spaces, between the sets of discs, in order to intercept large clumps of feed material, such as hay, corn and other bulk feed, or extraneous material in the feed. The interception of such large chunks or the like by the hammers imposes a strain on the hammers as they attempt to move the chunks into the screen space, but such movement is prevented by the stationary bars extending inwardly toward the rotor.

However, in order to manufacture a grinding tub which will attract users, it is necessary to make the tub of such a diameter that it is not unduly difficult to load the tub, as by a loose hay handling device or the like. The size of such a tub will accommodate along a radius thereof a hammer mill rotor whose discs extend from adjacent the center of the tub bottom to a point close to the outer peripheral wall, so that the swath cut by the rotor hammers will permit the hay or other material to settle to the bottom of the tub, rather than bridge across between the tub walls. With such an installation, the length of shaft necessary for the rotor is excessive, and an undue amount of vibration of the hammer mill rotor may be produced, due to flexing of the shaft. While the effect of a distorted shaft or lack of balance from some other cause can be compensated for by balancing weights, the effect of flexing of the shaft is difficult to counterbalance. In any event, the greater the length of the shaft, the greater is the effect of flexing, distortion, unbalanced weight or the like. In addition, it is desirable to reduce the cost of the apparatus and one item of considerable cost is the rotor shaft, hammers and associated parts. However, any reduction in cost should not result in a reduction in performance.

SUMMARY OF THE INVENTION In order to reduce cost without affecting performance, as well as minimizing vibration problems, a reduction in the length between bearings of the hammer mill rotor shaft, accompanied by a reduction in the length over which the sets of discs carrying the hammers extend, is secured by placing a rotor having a considerably shorter shaft, provided with a lesser number of discs and hammers, within a quadrant of the grinding tub, i.e. with the axis of the shaft parallel to but spaced from a radius of the tub bottom. Such placement of the rotor results in a radius of the tub passing from an inside corner of the effective path of the hammers to the outside corner of the effective path of the hammers. Thus, a swath through the hay or the like is cut by the hammers which has nearly the same length as the swath cut by a greater number of hammers rotating about a shaft mounted on a true radius of the tub bottom. The short distances, between the inside corner and the center of the tub and between the outside corner and the rotating side wall, are compensated for by deflector plates mounted on the tub bottom, which results in an effective swath of the hammer mill corresponding to the inside of the tub.

DESCRIPTION OF THE DRAWINGS FIG. 1 is a front elevation of a tub grinder in which are embodied the improvements of this invention.

FIG. 2 is a top plan view, on an enlarged scale, of the tub grinder of FIG. 1.

FIG. 3 is a top plan view, on a further enlarged scale, of a hammer mill rotor but shown partly in section, for clarity of illustration.

FIG. 4. is a cross section of the hammer mill rotor, taken along line 4-4 of FIG. 3.

FIG. 5. is a diagram ofa preferred arrangement of the hammers on the respective shafts of the hammer mill rotor.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT In general, as in FIG. 1, a grinding tub T is mounted on a wheeled frame F which is provided with a power compartment P and a conveyor C which may be utilized to discharge from the underside of the machine the ground material, such as hay, corn, and the like. The grinding tub T is provided with a stationary bottom 10 and a rotating circular side wall 11, while a hammer mill rotor R is mounted for rotation within an opening 12 in the tub bottom. As described later, the rotor R is provided with a plurality of sets of discs, between which sets of hammers are pivoted, for striking the fodder or the like to carry it around on the underside of the rotor and pulveri zing it until it is small enough to fall through a series of holes in a screen S of FIG. 4. Such a screen is disclosed in in greater detail in my aforesaid U.S. Pat. No. 3,743,191 but essentially comprises a curved plate spaced slightly from the outer edges of the path of the travel of the ends of the hammers and provided with holes or apertures 12a of the size to which it is desired to grind the hay, grain or the like. The screen Ssurrounds the lower half of the hammer travel, then extends upwardly at each side, for a short distance. The screen S is,.of course, below the floor 10 of thetub, while the path of the hammers extends upwardly above the floor, in order to cut a swath through the material moving around the tub. A series of bars 13 extend across a front portion of the opening 12 toward the rotor and nearly to the discs, but are interspaced with the sets of discs, as disclosed in my aforesaid U.S. Pat. No. 3,743,191. These bars have the purpose of restraining entry of a large clump of hay, a fence post, rock or the like into the grinding space.

In accordance with this invention, the rotor R, the sweep of the hammers of which is indicated by the broken lines 14, is placed in such a position that the swath of cut of the hammers, on the material moved thereover by rotation of the side wall, will extend between an outer are 15, shown in dot-dash lines, and an inner are 16, also shown in dot-dash lines. The side wall 11 is rotated in the direction of the arrow 17 and tends to carry the hay around over the rotor R, in the direction of the small arrows between the arcs l and 16. As will be evident, the radial distance between the arcs l5 and I6 is a substantial proportion of the actual radius of the tub. Hay or the material to be ground is fed into the tub in any suitable manner, such as by a loose hay handler, or the hay may be deposited in bales, inside the tub.

Stated another way, the rotor is placed in a quadrant of the tub, or with the rotor axis parallel to but spaced from a radius of the tub base, so that the width of swath cut by the rotor hammers in the material passing thereover will correspond generally to the hypotenuse of the hammer sweep, rather than merely the width thereof. In this way, the length of the shaft may be decreased to reduce vibration problems without unduly decreasing the capacity of the machine.

In order to insure that as much hay as possible, inside the tub, will engage the hammers, a curved baffle 18 formed from an angular piece of material having a bottom flange 19 may be attached, as by bolts as shown, to the bottom of the tub. The inner edge of the baffle 18, which need be only on the order of 6 inches high, is appropriately spaced the same distance from the side wall 11 as the outer are 15, as indicated by the are At the center of the tub, another baffle 20, of semieliptical shape, as shown, may be disposed to direct hay at the center of the tub outwardly toward the position of the hammers. The inner baffle 20 is conveniently mounted on a base 21 which, in turn, is attached, as by bolts as shown, to the bottom of the tub. The outer edge of the inner baffle 20 preferably extends to a point corresponding to the inner are 16, as indicated by the arc 16.

The rotating outer side wall 11 may be provided, at its lower edge, with a channel shaped, depending rim 23 which is engaged by a drive roller 24 on the outside, such as including a conventional automobile or truck tire. On the inside, a reaction roller 25 fits into the channel to hold the rim 23 against the drive roller 24, while additional rollers 26 fitting into the channel rim support and guide the rotating side wall. The side wall and its rim may also be supported on the underside for rotation by a series of horizontal rollers, such as a support roller 27 mounted on the frame F, as in FIG. I.

The rotor R, as in FIG. 3, includes a drive shaft 30 having a key 31 at each end and a key 32 at the center, adapted to be supported by bearings having their centers at a bearing centerline 33 at the left and a corresponding centerline at the right. Mounted on the drive shaft 30 are a series of single discs 34 and triple discs 36, with a pair of single discs 34 between each adjacent pair of triple discs. A double disc set 35 is at each end, while a spacing ring 37 or 38 is disposed between the respective discs, with ring 37 being a single ring and ring 38 being a dual ring. The center key 32 locks each of the discs and spacing rings to the shaft for rotation therewith. The discs 34, 35, 36 and spacing rings 37, 38

are clamped together between a pair of ring nuts 39, each held in a tightened position by a lock washer 40. Also rotating with the discs are four shafts 41, 42, 43 and 44 which are spaced 90 apart and which extend through suitable holes in the discs. Shaft 42 is opposite shaft 44 and is hidden in FIG. 3, but is shown in FIGS. 4 and 5.

As in FIGS. 3 and 4, a series of hammers 46, each having two holes 47 and 48, the additional hole permitting the hammer to be reversed in position when one end becomes worn, so that the opposite end can then be used in substantially new condition, is pivotally mounted through one of the holes 47 or 48 on a shaft 41, 42, 43 or 44, depending upon the position of the hammer, such as in accordance with the diagram of FIG. 5. In FIG. 5, the positions of the hammers 46 between adjacent discs are indicated by appropriate blocks, with the discs 34, 35 or 36 each indicated by a line or lines which is actually the projection of a circle in the disc at the shaft holes. In addition, each hammer is maintained in axial position on the corresponding shaft by a spacer or spacing ring 50 which is disposed between each hammer and the opposing disc or discs. It will be noted that, aside from the dual end discs 35, there are two spaced single discs 34 between each two adjacent triple discs 36, with a hammer or spacing ring being mounted on a triple disc or an opposing single disc. Thus, there are no hammers between the pairs of single discs, so that the bars 13 of FIG. 2 may extend toward or even into the spaces between the pairs of single discs. As will be evident, there is only one hammer on each shaft 41, 42, 43 or 44 between two adjacent discs in any one set, but the hammers are arranged in the respective sets of discs so that the hammers and spacers will be in corresponding positions outwardly from the center of the shaft, for dynamic balancing. Thus, the hammers are preferably disposed in a similar alternating pattern between the discs of each group from one end inwardly to a center between the bearing areas, and in opposed relation from the opposite end inwardly. The hammers are shown in FIG. 4 in a position in which the hammer extends directly outwardly due to centrifugal force.

As in FIGS. 1 and 2, the grinding tub T may be mounted in an off-center position with respect to longitudinal beams of frame F, so that the hammer mill may be mounted centrally of the frame F. A tractor power takeoff 61 may be connected to a gear box 62, in power compartment P, in turn connected directly to the shaft 30 for rotating the hammers. A pump may be driven from the gear box 62, while a fluid motor may be mounted within the power compartment P, to be driven by fluid supplied from the pump and connected to the drive roller 24, for rotating the side wall 11 of the grinding tub at a reasonably slow rate. Neither the pump nor the fluid motor are shown, since they may be constructed as disclosed in my aforesaid US. Pat. No. 3,743,l9l.

The framework F may be supported at the rear by a pair of wheels 63 mounted on an axle 64, while a front tongue 65 may be provided with an adjustable leg 66, for supporting the frame in a horizontal position when disconnected from the tractor. The conveyor C may include a single section or a pair of hinged sections, with the inner section pivotally mounted at its lower end on an outlet box 67 for the hammer mill, which outlet box contains an auxiliary conveyor. Conveyor C may be used as a level conveyor or as an elevating conveyor. For transportation from place to place, the conveyor may be held, as in FIG. 1, in an upper position by a winch operated cable arrangement 68 mounted on a post 69 which extends obliquely upwardly from the frame at a point just forward of the grinding tub. The bottom of the grinding tub may be supported by cross beams 70 which extend between the longitudinal beams 60 of the frame F, as well as cantilever beams 71 on the outside of the respective longitudinal beams.

As will be evident, the probability of vibration, as well as the effects thereof, will be reduced by utilizing a shorter shaft, i.e. distance between shaft bearings. As the hay circles around by engagement with the rotating side wall of the tub and is directed inwardly by outer baffle 18 or outwardly by inner baffle 20, sufficient hay or the like will pass within the lines and 16 that the capacity of the hammer mill will correspond to a radius of the tub.

It will be understood, of course, that a different number of hammers and discs and/or a different arrangement thereof may be used. Also, other embodiments of this invention may exist, as well as various changes made therein, all without departing from the spirit and scope of this invention.

What is claimed is:

1. A tub grinder comprising:

a stationary bottom;

a side wall rotating about said bottom;

a hammer mill including a rotor mounted on a shaft and provided with pivoted hammer means, with screen means on the underside of the periphery of the travel of said hammers as said rotor rotates:

said bottom having an opening in which said rotor is mounted, the axis of said rotor shaft being parallel to but spaced from a radius of said bottom and the path of the outer portions of said hammers being above said bottom, whereby the swath of cut of said hammers on the underside of material moved over said hammers by rotation of said side wall has a width corresponding essentially to the radius of the tub floor;

the inside corner of said opening being spaced from the center of said tub bottom and said opposite outside corner of said opening being spaced inwardly from said side wall; and

means adjacent the side wall for deflecting inwardly material moved around said bottom by rotation of said side wall, so as to intersect the swath of said hammers, said outer deflecting means being an arcuate, upstanding baffle mounted on said tub bottom and having its inner end spaced from said side wall a distance corresponding to said outside corner of said opening.

2. A tub grinder comprising:

a stationary bottom;

a side wall rotating about said bottom;

a hammer mill including a rotor mounted on a shaft and provided with pivoted hammer means, with screen means on the underside of the periphery of the travel of said hammers as said rotor rotates;

said bottom having an opening in which said rotor is mounted, the axis of said rotor shaft being parallel to but spaced from a radius of said bottom and the path of the outer portions of said hammers being above said bottom, whereby the swath of cut of said hammers on the underside of material moved over said hammers by rotation of said side wall has a width corresponding essentially to the radius of the tub floor, the inside corner of said opening being spaced from the center of said tub bottom and said opposite outside corner of said opening being spaced inwardly from said side wall; and

inner deflecting means adjacent the center of said tub bottom for deflecting outwardly material moved around said bottom by rotation of said side wall from the center portion of said tub and into the swath of said hammers, said inner deflecting means being a generally semi-elliptically shaped, upstanding baffle mounted on said tub bottom and having one arcuate end generally encircling the center of said tub bottom and its outer end spaced from said center a distance corresponding to that of said inside corner of said opening.

3. A tub grinder as defined in claim 2, including: an outer, arcuate, upstanding baffle mounted on said tub bottom and having its inner end spaced from said side wall a distance corresponding to said outside corner of said opening.

Claims (3)

1. A tub grinder comprising: a stationary bottom; a side wall rotating about said bottom; a hammer mill including a rotor mounted on a shaft and provided with pivoted hammer means, with screen means on the underside of the periphery of the travel of said hammers as said rotor rotates: said bottom having an opening in which said rotor is mounted, the axis of said rotor shaft being parallel to but spaced from a radius of said bottom and the path of the outer portions of said hammers being above said bottom, whereby the swath of cut of said hammers on the underside of material moved over said hammers by rotation of said side wall has a width corresponding essentially to the radius of the tub floor; the inside corner of said opening being spaced from the center of said tub bottom and said opposite outside corner of said opening being spaced inwardly from said side wall; and means adjacent the side wall for deflecting inwardly material moved around said bottom by rotation of said side wall, so as to intersect the swath of said hammers, said outer deflecting means being an arcuate, upstanding baffle mounted on said tub bottom and having its inner end spaced from said side wall a distance corresponding to said outside corner of said opening.

2. A tub grinder comprising: a stationary bottom; a side wall rotating about said bottom; a hammer mill including a rotor mounted on a shaft and provided with pivoted hammer means, with screen means on the underside of the periphery of the travel of said hammers as said rotor rotates; said bottom having an opening in which said rotor is mounted, the axis of said rotor shaft being parallel to but spaced from a radius of said bottom and the path of the outer portions of said hammers being above said bottom, whereby the swath of cut of said hammers on the underside of material moved over said hammers by rotation of said side wall has a width corresponding essentially to the radius of the tub floor, the inside corner of said opening being spaced from the center of said tub bottom and said opposite outside corner of said opening being spaced inwardly from said side wall; and inner deflecting means adjacent the center of said tub bottom for deflecting outwardly material moved around said bottom by rotation of said side wall from the center portion of said tub and into the swath of said hammers, said inner deflecting means being a generally semi-elliptically shaped, upstanding baffle mounted on said tub bottom and having one arcuate end generally encircling the center of said tub bottom and its outer end spaced from said center a distance corresponding to that of said inside corner of said opening.

3. A tub grinder as defined in claim 2, including: an outer, arcuate, upstanding baffle mounted on said tub bottom and having its inner end spaced from said side wall a distance corresponding to said outside corner of said opening.

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