US2200374A - Rotary pivoted hammer - Google Patents

Description

May 14, 1940. T. H. PoEsE ROTARY PIVOTED HAMMER Filed Aug. 22, 1938 f///ffffffflffffffJ Patented `May 14, 1940 UNITED STATES PATENT OFFICE 6 Claims.

This invention 'relates to certain new and usefulimprovements in rotary pivoted hammers, the `peculiarities of which will be hereinafter fully Vdescribed and claimed.

. More specifically, this invention relates-to such lhammers made of -plate steel and having their outer -ends formed in folds or corrugations extending backward from the front edge in the plane of rotation, so as vto make the front opera'tve edge thicker than the relatively thinshank portion.

The objects of my invention are to provide means first, for lessenng the resistance of the shanks in passing through the material being reduced and thus to operate the machine on correspondingly less power; second, to increase production and efficiency of the machine; third, to

reduce the loss of eiciency due to wear of thel operating edge of the hammer; fourth, for causing such wear so to change the operating edge of the vhammer so that -it is substantially selfsharpening; fifth, for spacing the hammers on their pivot rods; and other features of construction hereinafter-described and claimed.

In the accompanying drawing in which like reference numerals indicate corresponding parts.

Fig. 1 represents a vertical sectional elevation of a machine exemplifying my invention;

Fig. 2, an enlarged dat face View of one of -my hammers Vand portions of adjacent parts on which it is mounted, the main shaft and pivot rod being in section in the plane of rotation;

Fig. 3, anY edge View of said hammer and parts lshown in Fig. 2, the disks being in section;

Fig. 3a,a detail of the inner-end of my hammer; Aand Fig. A'La perspective view of the operative edge of saidhammer indicating the change produc-ed by Wear. -f

Referring to the .drawing the numeral l indicates the casing of a grinder in which is mountvedamain shaft 2 of a rotor on which are mount- `ed disks 3 spaced apart by collars 4. In these disks are aset of concentric openings in which aremounted rods 5 on which are pivoted the inner lend of the Shanks E of plate steel hammers Vwhich `extend outward till their outer ends are in close proximity to a perforated screen 'l through which the material being ground is discharged when it is suiiiciently reduced to pass through the perforations.

'A portion of the outer end of this hammer is increased in the thickness of its operating edge over the thickness of the ShankB, by being; formed inifolds or corrugations, the inclined portionsf (Cl. 83-11) -of which yform 90 angles ror .less with each other as shown in Fig. 3. The meeting edges forming ridges S of said folds are thus disposed alternately on opposite sides of the plane of the shank Vii so that the thickness of lthe operativeedge is 5 ysuchnthickness of the operative edge is substantially ve times the thickness of the shank. The outer end IS of said hammer is foldedapproximately straight across the .width of the Vhammer 1'5 face so that it rotates in close proximity to the perforated screen and facilitates the discharge-of the nely ground material through the perforations. As shownin Fig. 3, this corrugated outer end of the hammers forms .a zigzag operative 20 edge, and said hammers as mounted in the machine, are substantially parallel to each other in their shanks and zigzag operative edges.

The material entering the casing of the machine is subject to impact by the operative zigzag edges of the hammers until suiciently reduced to pass through the screen. The partly reduced material that passes inside the hammer circle of the outer ends l0 of said hammeraoiers little resistance to the rotation of the thin Shanks 30 lwhich pass through said material without Yas much rotative impulse thereon as would be the case if the Shanks Were as thickA at the operative edges as in the usual form of straight barpivoted hammers. 'I'hus the rotation of the rotor in 35 grinding with this form of hammer, requires less vpower to operate it than when thevusual form of hammers is used. Tests by ammeter'of this form of hammer shown and described-above, indicate that the power required is lessened by 10% as Q40 compared with the usualform of straight bar hammers in which'thethick shanks act .with a rotative action upon the material being reduced. Also with my form of hammer, the material is not carried around with the hammers. as much 45 as in the usual form, and therefore'the impact of the hammers upon. the relatively slower movement of the material, causes a greater'impact and increased efiiciency of reduction. Tests have shown that the output ofthe Vground material 5,0 is increased 25% by the use of my form of hammer above described.

Thus not only the lesser power required, :but the increased production obtained by :the use of my form of hammer, are of :advantage and JI5 5 increases the usefulness of the machine operated lwith hammers above described.

The thickness of plate steel used for making my form of hammers varies according to the material on which they are employed. Thus for )grinding soft material such as oats, barley, mill feed screenings, scrap leather, and such material, the preferred thickness of the plate varies from 11g to 1/8. Saw plate steel is preferred.

For grinding corn cobs, shelledv corn, ear corn, and such material the preferred plate thickness is l@ to 1/4 inch.

The thinner plate steel is preferred for grinding brous roots such as darris that is pulverized to form bug dust. Other roots such as tombo from Brazil, Cuba root from Venezuela, and a flower from Japan and intermediate islands to Java which is like a wild diasy and hard to grind is made into Pyrethrum powder by hammers of my construction.

Various chemicals and drug products such as salts and crystals which require impact more than cutting action, are reduced by hammers having a plate thickness of 1/8 to 1/4 inch. For instance, tartaric crystals for making cream of tartar are reduced by plate hammers of preferred thickness of 1A inch. l

The speed of rotation varies with the diameter of the hammer circle. Thus rotors having a 40" hammer circle are preferably run at 1800 R. P. M.; a 28 hammer circle, 3600 R.. P. M.; iand an 8" hammer circle at 9,000 R. P. M. in 'machines used in laboratories.

In grinding and pulverizing Egyptian rock, and other igneous or trap rock material, in which 'heavy impact blows are required, the greater thickness of plate is preferred in my hammers.

These hammers with their zigzag corrugated operative edges, are preferably formed by dies and at relatively low cost. The operative zigzag edges may be tempered if so desired.

The wear on said zigzag edge is indicated by dotted lines in Fig. 2 as being greatest in the inclined folds 8 connecting the meeting edges 9 which latter appeared to resist the wear more than the inclined portions 8. The extreme fold IU Wears its outer corners rounding as indicated in Fig. 4 and forms one side of the extreme tooth 9. Thus the resulting effect of wear upon the operating edge will form a series of teeth at the meeting points 9 which are caused by hollows or recesses produced by wear as indicated in the perspective view Fig. 4. The toothed edge thus formed is practically as eicient as the original zigzag edge, and the hammer is thus substantially self sharpening.

On the inner end of my hammer, I provide integral means for spacing the relatively thin shank between the disks 3 by producing a thickened inner end by a fold or single corrugation l0 (Fig. 3a) similar to those at the `outer end; or by turning the corners 6' of the inner end in respectively opposite directions as indicated in Figs. 2 and 3 so that they ll the respective space between the adjacent disks and space the hammers uniform distance apart as indicated in Fig. 3. The oppositely folded corners of the inner end present beveled edges and avoid hanging up on the edge of the disk when the hammers are disposed in such a position that the said corners engage the periphery of the adjacent disk as when the rotor is at rest or about to stop or start.

It will be noted that the two inner corners of the bar when turned outward are disposed substantially at right angles to the plane of the shank and their points formed by inclined edges, are adapted to bear on the respectively adjacent disks and thereby centrally dispose the Shanks between said disks. When the rods are so near the periphery that these oppositely turned corners rnay engage the periphery of the disks except when the centrifugal force causes the shank to be radially disposed, the inclined edges of the triangular projections, if they should engage the periphery of adjacent disks,.will make` only a sliding engagement therewith and thuswill not obstruct the hammer fromtakingit's radial position under rotation. These projecting portions near the outer and inner ends make the operative thickness Aof the ends substantially the same.

Thus my plate bar hammer is bent outward laterally at and near both ends. Also when the transverse corrugations extend from the front to the rear edge as shown in the drawing, the hammer can be reversed upon its pivot rod so as to present the rear edge as a new front operative edge and thus extend the life of the hammer.

These alternately and oppositely` inclined folds of the corrugations at the outward end of the bar, form meeting edges or ridges of the corrugations slightly rounded as shown in the drawing, of the operative edge, to facilitate forming the same by dies.

The portions 8 connecting the ridges of the corrugations may be straight as shown or otherwise formed. f

I do not limit myself uto the exact construction herein shown and described except by the appended claims. l

Having thus fully described my invention, what I claim as new and desire to secure by Letters Patent, is:

l. A rotary pivoted hammer-,comprising a fiat plate bar forming a shank adapted for pivotal mounting at its inner end and having at its outer end corrugations extending transversely backward from its front edge and laterally from the plane of the shank so arranged in transverse folds that adjacent ridges lie alternately on one side and then the otherof the radial plane of the length and width of the bar, forming a zigzag operative front edge.

2. A rotary pivoted hammer comprising a fiat plate bar forming a relatively thin shank com pared to its width and having alternately inclined folds at its outer end forming ridges offset laterally and altcrnatelyfromboth flat faces of the shank, and connecting `the front and'rear edges of the bar transversely to the length of the hammer, andA so arranged that adjacent ridges lie alternately on one side and then the other of the radial plane of the length and width of the bar, to increase the effective thickness of the operative edges over the thickness of said shank.

3, A rotary pivoted hammer consisting of a at bar relatively thin compared to its width and forming a ilat, thin shank, and having transverse folds forming corrugations at its outer end and thus increasing the effective thickness of its operative edge while maintaining the thinness of said bar throughout its length, said transverse folds being so arranged that adjacent ridges lie alternately one one side and then the other of the radial plane of the length and width of the bar. i

4. A rotary pivoted hammer of plate `steel bent into transverse folds and ridges at and near its outer end, said transverse folds being so arranged that adjacent ridges lie Valternately on one side u and then the other of the radial plane of the length and Width of the hammer, and said ridges being oiset from opposite faces of the hammer and adapted to form teeth in the operative edge when the wear under usage makes conc-ave recesses in the connecting folds.

5. A rotary pivoted hammer of plate steel characterized by having oifset, laterally projecting portions near each end, said portions near the outer end lying in transverse folds that are so arranged that adjacent ridges lie alternately on one side and then the other of the radial plane of the length and Width of the hammer, and the portions at the inner end projecting sufficiently to make the said ends substantially the same operative thickness.

6. A rotary grinding machine comprising spaced disks on a rotary shaft and having a set of pivot rods passing through said disks adjacent their periphery, in combination with plate steel rectangular bar hammers pivoted on said rods and characterized by having their two inner corners turned outward substantially at right angles to the plane of the shank forming triangular projections having edges inclined to the radial plane parallel to the disks, of the length and widthof the shank and forming offset points having inclined edges meeting from opposite directions adapted to bear on an adjacent disk to position in a deiinite operative plane the shank of the respective hammer, and the slanting edges of said projections being capable of sliding engagement with the periphery of the adjacent disk tor.

THEODORE I-I. POESE.

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