US2170407A - Hammer mill - Google Patents

Description

Aug. 22, 1939. s. D. HARTSHORN HAMMER MI LL Filed Nov. 2, 1956 4 Sheets-Sheet 1 lllll /1// VENTOR BY mm W n m.

ATTORNEYS Aug. 22, 1939. s. D. HARTSHORQN HAMMER MILL 4 Sheets-Sheet 2 Filed Nov. 2, 1956 NVENTOR 3 Q 2% B 24ml, BM

ATTORNEYS Aug. 22, 1939. s. D. HARTSHORN HAMMER MILL Filed Nov. 2, 1936 4 Sheets-Sheet 3 m mu mu 0% Q H Rm [W a a I A O 0 |H 0 W I 0 W H G I 1W1 I a 0 7/ MG WI 1. O O v Hull. 0 0 k [I k 0 o O O a 0 MN NR 0 v o o o, .ww o 0 O O ENTOR W @W-rq PM ATTORNEY;

S. D. HARTSHORN HAMMER MILL Filed Nov. 21 1956 4 Sheets-Sheet 4 SAM/L, @WM PM ATTORNEYS Aug. 22, 1939.

Patented Aug. 22, 1939 UNITED STATES HAMMER MILL Stanley D. Hartshorn, Philadelphia, Pa., assignor to Pennsylvania Crusher Company, Philadelphia, Pa., a corporation of New York Application November 2, 1936, Serial No. 108,699

8 Claims.

This invention relates to crushing equipment,

' and more particularly to that class of equipment known as hammer mills, adapted for crushing or breaking coal and the like.

The principal object of this invention is to provide an effective crushing machine which is simple and inexpensive and in which compensation and adjustment for wear may be effected.

The hammer'mills according to this invention comprise a rotating hammer system within a perforated cage enveloping the hammers. The periorated cage is preferably constructed of bars against which the material impelled by the hammers strikes and breaks. When the material is broken small enough it passes out of the cage between the bars. The hammers and the cage are preferably symmetrical so that the direction of rotation of the hammers may be reversed, thereby wearing the opposite hammer faces and cage bar edges. The machine is self sharpening because during rotation in one direction the hammer and cage bar edges corresponding to rotation in the opposite direction are being sharpened. The perforated portions of the cage are constructed in adjustable sections to permit adjustment with reference to'the hammers to provide control of the crushing operation and compensation for wear. Features of the invention reside in the means for securing relatively easy adjustment of the cage sections. .A subsidiary feature is the use of eccentrics for this purpose. According to one embodiment the adjustable sections are pivoted near their upper ends.

Another feature is the provision of a pocket for collecting tramp iron and the like, so situated that it is effective for either direction of hammer rotation.

The above and other features of the invention will be better understood from the following detailed description of specific embodiments, with reference to the accompanying drawings, of

which:

Fig. 1 is an end view partially in section taken at line II of Fig. 2.01 a machine embodying the invention;

Fig. 2 is a side sectional view taken along line 2.2 of Fig. 1;

Fig. 3 is a side sectional view of a somewhat different machine embodying the invention; and

Fig. 4 is a side sectional view of another machine embodying the invention.

The machine shown in Figs. 1 and 2 comprises a frame I which supports and encloses the machine. Supported within the frame I0 is a generally cylindrical cage formed by solid breaker plates II and I2 and arcuate screening cage sections I3 and I4 which are pivoted respectively at their upper ends on pivot pins I5 and IS. The duplex screening sections I3 and I4 are formed by a frame of arcuate ribs shown at IT and I8,

to which are fastened longitudinally extending screen bars I9 which form screening spaces therebetween. The portions of sections I3 and I4 above the screen are provided with solid breaker blocks 2| and 22, respectively; and the portions of these sections below the screens have pinching blocks 23 and 24, respectively.

The two screening sections I3 and I4 are provided with fiat surfaces 25 and 26, respectively, which rest against respective eccentrics 21 and 2B which are pivoted at 29 and 30. The eccentrics are turned by a handwheel 85, the shaft of which is geared to the eccentric pivots. The two eccentrics may be simultaneously operated by the same handwheel, or if desired, they may be operated individually by separate handwheels or the equivalent. The space 3| between the lower ends of the screening members contains a centrally located kick-off plate 32 pivoted at 33, the function of which will more fully appear hereinafter.

The machine is provided with a hammer mechanism as follows: A shaft 34 extending longitudinally through the cage is mounted at the ends in bearings 35 and 55, of which bearing 35 is illustrated in detail. This is a roller thrust bearing having rollers 36, an outer roller guide 31 held within the hub of the bearing, and an inner roller guide 38 forced over a tapered part of shaft 34 by a nut 39. Dust rings 40 and 4| are provided at each end of the bearing to keep out dust and grit.

The hammer mechanism comprises a number of flanges 42 regularly spaced along the shaft, within the cage by collars 43. The last flange abuts against the collar 44 which is integral with the shaft. The assembly of the flanges 42 and spacers 43 is held tightly in position against collar 44 by suitable means at the opposite .end such as a nut (not shown). Several rods 45 (three in this case) extend longitudinally through suitable holes in the flanges 42 at regularly spaced intervals around the circumference of these flanges, and fasten in place in a suitable manner. Hammers 45 having hammer heads 41 are pivoted on the rods 45 within the spaces between the ad jacent flanges 42. The hammer shaft is located somewhat below the central position of the cage, so that the hammers are considerably closer to the lower portions than to the upper portions of the cage.

A feed chute 48, having a rectangular crosssection enters the cage from the position centrally above the hammer mechanism, as shown, for the purpose of delivering material to be crushed into the cage.

In operation, the hammer shaft 34 is rotated by an external source of power (not shown). The material to be broken is fed from the feed chute 48 into the cage. The rotation of the hammer shaft causes the hammers 46 to extend out radially; and the hammer heads strike masses of the material which have dropped from the chute, knocking them against the breaker plates and blocks and the screen bars of the surrounding cage. When the shaft is rotating clockwise (Fig. 2) many of the'masses of material strike the sharp edges 49 of the screen bars, thereby serving to break up the material. Those pieces of the material which are broken small enough topass through the spaces 20 between the bars pass into the chamber. below the cage and into a suitable receptacle. Those pieces of the material which are still too large to pass through the screen remain in the cage until they are broken small enough. Material which does not pass through the screen bars passes down into the region of the pincher plates 23 and 24. In the case of clockwise rotation such materials is present at pincher plate 24. Owing to the small distance between the hammer and the pincher plate, the material is readily picked up by the hammers and thrown against the kick-off plate 32, which for this direction of rotation should be turned at the angle shown in dotted lines at 32a. The kick-off plate serves to receive impacts of the material, break it up, and direct it down into the receptacle below. The angle of this plate can be adjusted at pivot 33 to produce the most desirable action. It will be turned in the direction opposite to 32a in the case of rotation in the counterclockwise direction.

In the case of clockwise rotation, much of the material impelled by the hammers strikes and scrapes along the further edges of the bars, thereby serving to sharpen these further edges at the same time that the nearer edges 49 are being dulled by the direct impact of material. Similarly, there occurs much scraping of material along the outer faces 52 of the hammer heads, so that the further edges 53 thereof become sharpened at the same time that the nearer edges 54 are becoming dulled by the impacts. After the machine has been run in the clockwise direction for some time and the edges 54 and 49 have become dulled, the machine may then be rotated in the opposite direction (counterclockwise in Fig. 2) to take advantage of the sharpened edges 5| and 53. During this direction of rotation, the edges 49 and 54 become resharpened in the manner described above. Thus, the breaking edges of the machine are self-sharpening. Furthermore, their reversibility permits double wear of the hammer heads because it is unnecessary to replace the heads until both sides become worn.

The movable screening members I3 and I4 of the cage are susceptible of adjustment by reason of the pivots l5 and I6, and the eccentrics 21 and 28. To move the cage members closer to the hammers it is only necessary to rotate the eccentrics 21 and 28 a suflicient amount. This permits compensation for wear or a desirable adjustment for producing a satisfactory breaking operation. The most critical adjustment is near the bottom of the cage at the pincher plates, where the hammers pass close to the cage; and it is at these places that considerable wear is likely to occur. The arrangement of the pivoted duplex screen sections provides easy adjustment at these lower regions because the action of the eccentrics, near the bottom, is to push the pivoted sections both horizontally and. vertically, that is, inwardly and upwardly,

Fig. 3 is a sectional view of another form of a reversible duplex cage type hammer mill in.which the screening members are pivoted at the bottom instead of from above. The reversible hammer shaft 55 is provided with hammers like those in Figs. 1 and 2 except that more hammers are used and they are staggered with reference to the spaced flanges; that is, adjacent hammers around the periphery of the flanges are positioned on opposite sides of the flanges. The duplex screening cage sections 56 and 5! are pivoted on a floating pivot shaft 58 located centrally below the cage, by pivot arms 59 and 60 which extend to the pivot from the screening sections.

The screening sections are adjustable at their upper ends by lever arms 6i and 62, respectively, pivoted on shafts 63 and 64, and attached to the cage members by pivot pins 65 and 66. These cage members are both simultaneously adjustable from a single handwheel 67 which turns shaft 63 and 64 by worms 68 and 69 which mesh with gears and H on shafts 63 and 64, respectively.

Two angulated breaker plates 12 and 73, extending longitudinally along the upper roof of the cage, are provided with sharp or angular surfaces 74, I5 and 16. extend the length of the cage and have webs at the ends thereof for fastening to the frame. The space between members 56 and 12 is filled in by a solid member 1'! extending longitudinally and bolted by end webs 18. A similar member 19 is provided at the opposite side of the cage.

The feed chute 8D enters the cage from a position centrally above the hammer shaft and between the breaker plates 'l2 and 73.

The space 8| between the lower ends of the screen sections 56 and 51 provides a pocket into which such material as tramp iron is thrown. This pocket is provided with a base plate 82 held in place on one side by a hinge 83 attached to the base plate and to a depending plate 8! attached to screen section 51. On. the opposite side the base plate is fastened in position by a locking member 88 pivoted at pin 89 attached to screen member 56. The hinge 83 is provided with a counterbalance 84 so that the base plate moves back to the closed position even after it has been unlatched and opened.

The operation of this machine is somewhat similar to that of Figs. 1 and 2. The sharp or angular portions of the breaker plates 72 and I3 aid in braking up the material, as well as the sharp bar surfaces of sections 56 and 51. The cage sections 56 and 51 are adjustable by the handwheel 6'! which moves the upper portions of these members inwardly and outwardly. An eccentric, such as eccentrics 2! and 28 of Fig. 2, may be substituted, if desired, for the lever arms 61 and 62. The tramp iron and the like is removed from the lower pocket 8| by unlatching and opening plate 82. Since this pocket is located at the bottom it is effective to collect tramp iron regardless of the direction of rotation of the hammer shaft.

Fig. 4 illustrates a machine very similar to that of Figs. 1 and 2 in that the adjustable duplex cage sections are pivoted from above and are adjustable from below; but these sections are shown in Fig. 4 provided with means for more accurate adjustment. and 9! are made eccentric .as shown, so that the cage sections may be more readily raised or lowered in a generally vertical direction. It is understood, of course, that the eccentrics could be replaced by ordinary shafts as in Fig. 2, making the cage sections act as ordinary hinges. Horizontal and upward adjustment is provided by link lever arms 92 and 93 at a lower portion of one of the adjustable cage sections, and cor- These angulated members,

The pivots 90 i responding lever arms 94 and 95 at' the other charge opening between the lower margins of the adjustable cage section. Thesellink lever arms are fastened to the cagesectionsby pins 96 and 91, respectively; and they may be. adjusted independently by independent rotation of shafts 98 and 99. An eccentric cam arrangement such as cams 21 and 28 in Fig. 2 may be substituted for the link lever arms if desired.

Since pivots 90 and 9| are located a considerable distance above the upper screenbars'of the cage sections, an inward movement at pins 96 and 91 produces substantialinward movement at the upper as well as the lower screen bars; and because pivots 90 and 9| are located considerably outside the screen bars an upward movement at pins 96 and 91 produces substantial'upward movement at the lower screen bars. This kind of cage adjustment by which the cage sections move approximately along a line through the center of the hammer shaft at 45 to the horizontal, is the kind desired for the compensation of wear. The adjustability is more per- .fect when the pivots 90 and 9! are eccentric.

, A tramp iron pocket is formed at the bottom of the cage between the two adjustable members by an arcuate member I00 pivoted at IOI, having by its sloping sides, forms a seal between the two cage sections, and since the sections move inwardly and upwardly at approximately the same angle as the slant of the pocket walls, i. e. about 45 to the vertical, the seal is maintained at all cage'adjustments.

I claim:

1. A hammer mill comprising a cage having a pair of oppositely located screening sections, a system of rotating hammers within said cage, a pocket between said sections at the lower part of saidcage, said pocket having walls which slant downward and outward at a. predetermined angle to the verticalfand said cage sections being adjustable inwardly and upwardly. at substantially the same angle, whereby said pocket seals the space between said sections regardless of the position'of adjustment.

2. A hammer mill comprising a cage, a rotating hammer system within the cage, and means for feeding material to the cage, said cage comprising juxtaposed screen members, a pocket located between the lower ends of the screen members and having a bottom provided with faces cooperating with said lower ends of the screen members to maintain a discharge gap of predetermined width, and adjusting means for shifting the screen members relative to the path of the hammers in a direction parallel to said faces to maintain said gap between said faces and screen members.

3. A hammer mill comprising a cage, a rotating hammer system within the cage and means for feeding material to the cage, said cage comprising screening members on opposite sides of the hammer system and having a permanent disscreen members, below the-axis of said system, and an impact plate located in said opening in the lower part of the path of travel of material impelled by the hammers along either screen member.

4. A hammer mill comprising a cage, a shaft carrying a rotating system of hammers within said cage adapted to engage material at the top central portion of the hammer circle, a top central means for feeding into said cage at the top of said hammer circle material to be crushed, said cage comprising a pair of oppositely located screening sections symmetrical with relation to said top central feed and hinged on pivots near their upper ends and having adjusting means for moving their lower ends toward each other, said pivots being located a considerable distance above said shaft whereby the screening portions of said caged sections near said hammers and horizontally opposite said shaft are moved horizontally inward a substantial distance by inward motion of said lower ends, and said pivots being located a considerable distance outside the screens whereby inward movement of said lower 1ends causes them to move upward at the same ime.

5. A hammer mill comprising a cage, a. shaft carrying a rotating system of hammers within said cage adaptedto engage material at the top central portion of the hammer circle, and top central means for feeding into said cage at the top of said hammer circle material to be crushed, said cage comprising a pair of oppositely located screening sections symmetrical with relation to said top central feed and hinged on pivots near their upper ends and having adjusting means for moving their lower ends toward each other, said pivots being located a considerable distance above said shaft whereby the screened portions of said cage sections near said hammers are moved inward a substantial distance by inward motion of said lower ends, and said pivots being located a considerable distance outside the screens whereby inward movement of said lower ends causes them to move upward at the same time, and adjusting means for said pivots at said upper ends of said sections whereby the position of said sections may be adjusted at both their upper and lower ends.

6. A hammer mill as set forth in claim 5 in which each of the screening sections is adjustably pivoted on a rotatable eccentric located at its upper end and adjustably fastened near its lower end whereby the positions of said members may be adjusted in both a horizontal and in a vertical direction.

'7. A hammer mill comprising a cage, a system of rotating hammers within said cage and means for feeding material to be crushed into said cage, said cage comprising a pair of oppositely located screening members and a pocket in the space between the lower ends of said members for collecting tramp iron and the like, said pocket having a concave bottom shaped with reference to'the lower portion of said cage members so that the space between said members is always sealed regardless of the adjustment of said members toward or away from each other.

8. A hammer mill as set forth in claim 5 in which the screen sections are connected at their lower ends by a transversely movable pivot.

STANLEY D. HARTSHORN.

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