US2368870A - Comminuting apparatus - Google Patents

Description

1945. J. F. PAGENDARM COMMINUTING APPARATUS Filed Feb., 1, 1945 4 Sheets-Sheet l INVENTOR. JafiMFPQQPA/QWM. BYZ

Feb. 6, 1945.

J. F. PAGENDARM COMMINUTING APPARATUS Filed Feb. 1, 1943 4 Sheets-Sheet 2 INVENTOR.

ZWZ7776w 7/Pm Feb. 6, 1945. J. F. PAGENDARM COMMINUTING APPARATUS Filed Feb. 1, 1945- 1 Sheets-Sheet 3 Feb. 6, 1945. F PAGENDARM 2,368,870

COMMI NUTING APPARATUS Filed Feb. 1, 1943 4 Sheets-Sheet 4 I INVENTOR. v Ja/yMiF7776fw/PFM Patented Feb. 6, 1945 UNITED sTATEs PATENT oFFlcE 4 Claims.

This invention relates to a machine or apparatus comminuting or reducing metals such as magnesium, aluminium and the like into minute particles preparatory to further reduction by grinding, attrition, or otherwise to powder form.

t is well known that magnesium in powder form is at the present time extensively employed in the manufacturing of incendiary bombs, flash bombs, flares, tracer bulletsand the like. Several methods are employed but most of them depend upon extensive grinding operations to reduce the metal to the degree of fineness required. The reduction of magnesium metal from ingot or other solid form to powder is extremely hazardous, and the hazard increases as the ize of the metal particles decrease as the tendency to oxidize and ignite increases with degrees and particle size due to greater surface exposure, hence, if grinding canhe reduced to a minimum, the hazard is proportionately decreased.

The object of the present invention is generally to improve and simplify the operation of reducing metals of the character described to powder form, and especially to provide an efficient cutting operation whereby metal in ingot form i rapidly cut to such minute particles that the final grinding operation is reduced to a minimum.

A form of cutting machine that may be employed is shown by way ofillustration in the accompanying drawings, in which:

Fig. 1 is the side elevation of the machine;

Fig. 2 is a front viewof the machine;

Fig. 3 is an enlarged detail view partially in section of two cooperating clutches and thedriving mechanism used in conjunction therewith;

Fig. 4 is a perspective view of a portion of the rotary cutter;

Fig. 5 is a diagrammatic view showing the staggering of the cutting points;

Fig, 6 is a perspective view of the metal ingot to be cut;

Fig. 7 is an enlarged detailed view of the lower end of the feed shaft showing thechuck carried thereby and the feed nutwhereby the feed of the shaft is controlled;

Fig. 8 is a plan view of a pair of steady rest arms which engage the lower end of the metal ingot when it is brought into engagement with the rotary cutter; and

Fig. 9 is a perspective diagrammatic view of the clutch controlling mechanism.

Referring to the drawings in detail and particularly to Figs. 1 and 2, A indicates a frame one-half of the length of the feed shaft carries constructed of angle and channel shaped structural members. Supported on cross members 2 of said frame is an electric motor 3 and driven thereby is a shaft 4 on one'end of which is secured a rotary cutter B, the detail of construction of which will'later appear. Journalled in bearings 5 secured to the frame is a jack shaft '8 and similarly journalled in bearings I is a secondary jack shaft 8. Disposed in a vertical position within the frame directly above and in alignment with a rotary cutter B is a feed shaft C onthe lower end of which is secured a chuck D. The upper end of the feed shaft extends through a worm gear 9 journalled in a bearing II). The shaft is vertically movable through the worm gear as it is splined thereto, and as such the worm gear serves to rotate the feed shaft, but at the same time permits, vertical movement of the feed shaft as it is fed in an upward or downward direction. Approximately The material to be cut or reduced to powder form, for instance magnesium metal, is for the sake of convenience preferably supplied in long bars such as indicated at E (see Fig. 6). The bars are circular in cross section, and when placed in the machine, are secured at the upper end by the jaws I6 of chuck D,.and when secured are fed downwardly into engagement with a rotary cutter B and once in engagement therewith, the feed is automatically regulated to in- -sure chips which are minute. in size, and fur- This, in turn is rotated by a worm pinion and pulley 9a driven by a belt 23a which in turn is driven by a pulley .23

which i mounted on'a secondary jack shaft 8. .Thisdrive serves a main function, to wit, that of j rotating the feed sha ft C togetherwith the chuck D and the ingot E held thereby. It also serves one other function, to wit, that of. rapidly retracting or elevating the feed shaft C and the chuck D when the cutting operation of an ingot is complete.

The worm gear l4 together with the nut I2 forming a part thereof is driven by a worm pinion and an adjustable pulley Ma which in turn is driven by a belt 20a and an adjustable pulley 20'mounted on the main jack shaft 6. If the pulley I 4a is driven at the same speed as the pulley 9a, feed shaft C will rotate, but it will not feed either upwardly or downwardly. Hence, if a predetermined rate of downward feed is required, pulley Ma must be driven at a slightly slower speed with the result that the feed shaft is fed downwardly at a speed which insures the" cutting away of the lower end of the ingot at a rate which determines the size of the chips being cut, This predetermined rate of feed continues 1 until a mere stump of theingot bar remains in the chuck. At this time the direction or rota tion of the worm gear 9 and the feed shaft is automatically reversed causing the feed shaft and chuck to be rapidly elevated until a predetermined'raised osition is reached, and when this position is reached, the drives through the belts 23a and 20a are automatically disconnected and the feed shaft comes to rest so that the stub of ingot metal remaining in the chuckmay be removed and a new ingot or bar is inserted.

This is accomplished as follows:

a clutch section I8. Thus when the clutch sections l6 and Mia areengaged, the jack shaft will be driven and when the clutch sections are disengaged, the jack shaftwill remain at rest. Pulley I5 is driven continuously from shaft 4 by a pulley l5u and a belt [5b but the jack shaft 6 ecured thereto two sprocket gears l8 and I9 and the" pulley which through belt 20a drives the pulley Ma. The secondary jack shaft 8 carries a sprocket gear 3a which. is, driven from the sprocket I8 by a chain l8b. The -sprocket gear um. (see Fig. 3) carries one-half of a jaw clutch 24- which is'adapted to be engaged by a complementary clutch section Zia. Sprocket gear I811 and the .clutch section 2I' carri'ed'thereby are freely rotatable on the shaft 8 and only transmit power to the complementary clutch section am when this is moved longitudinally on the shaft into engagement. Keyed or otherwise secured on shaft 8 is a sprocket gear lea which carries, or has secured thereto, one-half of 'a cone clutch 22. Freely rotatable on" the shaft 8- is a complementary cone-clutch section 2211', and carried or secured thereto is the pulley 23 which,.through belt 23a, transmits power to the pulley 9a. Pulley 23 is also secured to the jaw clutch section 2 la and this together with the pulley 23' and the cone clutch section 22a are longitudinally movable and freely rotatable on shaft 8. A clutch actuating lever 24 pivoted at its end to the frame'as indicated at 24a serves the function of moving the clutch sections 21a and 22a into or out of engagement with their complementary clutches. An idler shaft 25 is journalled in the frame above the secondary jack shaft '8 and carries a; sprocket gear 25a. A'sprocket chain- 25b-pas'sesover'ithe .rotates only when the clutch sections it and [6a I are engaged. The shaft 6 has keyed or otherwise sprocket gears l9 and 25a and behind the sprocket gear l9a so as to drive thi sprocket together with the cone clutch section 22 and the shaft 8 to which they are keyed in a direction reverse to the other shafts. The operation of the several belts and sprocket chain drives and the cooperating clutches is as follows:

If the feed shaft C has been elevated to its upper-most position and a new ingot or bar inserted in the chuck, a hand wheel 27 secured on the pulley shaft Ma is grasped and rotated so as to feed the shaft C and chuck D downward ly until the lower end of the ingot just contacts the rotary cutter B. The clutch actuating lever 24' is next grasped and swung about its "pivot 24a in a right hand direction, thus engaging the jaw clutch sections 2| and 2Ia, and finally the clutch actuating lever I! is grasped and swung to engage the jaw clutch sections I6 and a. Power will thus be transmitted from shaft 4 through pulley l-Ba, belt ifib and pulley I5 to drive the main jack shaft 6. This will in turn drive the pulley 2! the belt 26a and the pulley Mawhich drives the worm gear l4. Power is at the same time transmitted through sprocket gears l8 and IE0. and the chain. I-8b to drive the clutch sections 2i and 2m and the pulley 23' in the same direction as jack shaft 6 and, as the pulley 23 is driven it will transmit power through. the belt 23a to the pulley 9a and the worm gear 9; thus transmitting a rotor motion to the feed shaft, and, as the nut carried by the worm gear id is also rotating, but at a slightly slower speed than the feed shaft C, this shaft will gradually feed in a downward direction causing the lower end of the ingot to be cut away by the rotary cutter at a. given rate.

The cutting operation will continue until a small stub. is left in the chuck D as indicated at e in Fig. 7. At this time a disc 28 (see Figs. 1 and 9) which is secured inthe feed shaft C Will engage an arm 29 which is secured ona vertically disposed rod 30 which is slidably mounted and guided in the frame. This rod carries a pin 3! adjacent its lower end which extends through the forked end 32of a lever 33 which is pivotally attached as at 34 to the clutch actuating lever 1 24. When the disc 28 engages the arm 29 carried .by the rod 30, the rod will be forced in a downward direction, and as the pin 3| carried by the rod engages the forked end of lever 33,'it will swing the forked en'd downwardly about the pivot 34 and cause a latch 35 formed on the upper side of the lever to move out of engagement with a retainer 36 which is stationary and secured to theframe. The .moment the downward movement of the rod Wis-sufficient to clear the latch 35 with relation to the retainer 36, a spring indicated at 31 which is connected withthe clutch actuating lever 24 and the frame will pull the lever towards the frame or in a left hand direction. The law clutch sections 2| and 2m will thus be disengaged and at the same time, the cone clutch sections 22 and 22a will become engaged and as the cone clutch section 22 is driven by the sprocket ISa' in a reverse direction due to the arrangement of the chain 252) which passes over the sprockets I9 and 25a and behind the sprocket 19a; the direction of rotation of the pulley 23' will be reversed and so will the direction of rotation of pulley 9a and the worm gear.9. This reversal causes the feed shaft to rapidly become elevatedandas it moves upward- I ly, the disc 28 will engage. an arm which is secured on. arod; .41, fwhichyisi also vertically should stick, the release of the latch wouldbe disposed and slidably guided'in the frame. This rod has a pin 42 secured adjacent its lower end which engages the end 43 of a lever 44 which is pivotally attached as at 45 to,theclutch actuating lever IT. The lever 44 also carries a latch member 46 which normally engages a stationary keeper 41 secured to the frame. Now as the rod 4! is moving in an upward direction,.the pin 42 carried thereby will raise the forked end of the lever 44 or swing it about the pivot 45 and a point will finally be reached where latch 46 rides out of engagement with the keeper 4?. At that moment, a spring 48 secured to the frame at one end and to the lever 44 at the opposite end will exert a pull on the lever 44 and the clutch'actuating lever l1 and pull it towards the frame or in a left hand direction, and as the lever l! is pivoted to the frame as at 59, the jaw clutch sections I6 and 16a will be disengaged and thejack shafts 6 and 8, and all mechanism driven thereby, will come to rest The only part of the machine which will continue operation will be the electric motor, the shaft 4 driven thereby, the cutter B carried bysaid shaft, and the pulleys l5 and l5a. At this time the jaws E6 of clutch D may be opened (see the detailed construction of the jaw clutch in Fig. '7) the stub e removed and a new ingot inserted and secured. The hand --wheel 21 is then rotated to bring the lower end of the ingot into engagement with the rotary cutter B. Clutch actuating lever 24 is then grasped and swung to the right causing the jaw clutch sections 2| and 2la to engage and clutch actuating lever I1 is finally swung to the right causing the. jaw clutch sections l6 and Ilia to engage, thereby setting the jack shaft 6 and 8 in motion and the parts driven and connected therewith. The feed shaft will accordingly rotate and at the same time feed in a downward direction .at'a given rate, andthis will continue until a mere stub of ingot metal is left in the chuck at which time the disc 28 on the feed shaft will engage the arm 29 to causedownward movement of the rod 36 so as to cause automatic disengagement of the jaw clutch sections 2| and Zia and simultaneouslyengagement of the cone clutch sections 22 and 22a thus reversing thedirection of rotation of the worm gear 9 to cause rapid retraction or elevation of the feed shaft and the chuck. When it reaches, a predetermined raised position, disc 28 will again engage the arm 40 and raise the rod 4! so asto automatically disengage the jaw clutch sections it and Ilia thereby bringing themachine to rest so that the ingot stub may be removed and a 'new ingot in serted.

If for any reason one or another of the clutches should tend to stickor one or the other of the springs 31 and 48 should break or weaken, the automatic functioning or release of the clutches would not be dependable. Means, have accordingly been provided whereby positive functioning may be insured. This is accomplished by placing a cam 33a on the under side of the lever 33 and a similar cam 44a on the upper side of the lever 44. The faces of these cams present an angle of 45 or more and they are so positioned that they will engage a stationary bar .52 when the latches 35 and 46 are released with relation to their respective keepers. Normally when either latch moves out of engagement with its keeper, the cooperating spring will function and the cooperating clutch actuating lever will be pulled or swung to the left but if the spring should be broken or weakened or the associated clutch ofno avail but asone or another of the cams 33a.orr 44a is now in contact with the bar 52 and either downward or upward movementof the rods continues, the cams will react with the bar 52 and pull on the levers 33 and 44 with a sufficient force to insure operation of the clutcl-lactuating levers. J i

It should be noted that the rod 30 is provided with a lift spring 30a (see Fig. 2). This spring is a compression spring and has suiiicient lifting force to overcome the weight of the rod and t0 normally maintain it-in a raised'position where latch 35 is maintained in engagement withits keeper 36. 'NO spring is required in connection with rod M as latch 45 assumes a reversed position with relation to latch 35;hence the weight of rod 4! may be and is utilized ,to retain latch 46in engagement with its keeper 4?. It should be also noted that while the rods 3!] and 4| are normally intended to be automatically actuated by the disc 28 carried bythe feeding sh'aft C that it is also possible to actuate them manually as by the lever indicated at 60. This lever engages one or an other of a pair of pin am and 42a secured on the respective rods; thus by raising or. lifting lever 60, clutch actuating lever I! is operated and clutch sections 16 and Mia are released and conversely by pushing down on the lever, the clutch actuatinglever 24 is operated and the feed shaft C is thrown into reverse. The manually actuated lever 60 is important .as it may be necessary from time to time to raise the ingot bar from the. cutter or to stop the feed for one reason or another. r

The rotary cutter B maycfor all practical purposes be termed a millin cutter but it dis tinguishes from the ordinary milling cutter in that the teeth 12 (see'FigA) are ground along the cutting edge to form a serrated edge or a series of V shaped cutting points such as indicated at 13. 4 Not only that, but it should be noted that the points 13 are staggered; for instance, see Fig. 5, the points 13 of a tooth are shown in full lines, the points in the next tooth are indicated in dotted lines at 13a and in the neXtor following tooth at 1312. By. this staggering arrangement minute chips may be cut from the ingot bar; for instance, if the spacing between the cutting points 13 is /50 of an inch then by staggering the teeth as indicated in Fig. 5, the spacing between the successive cuts will be /ito of an inch, hence very materially reducing the size of the chips.

. In actual practice inasmuch as the cutting points are V shaped, a cross-section of the chip cut from the ingot bar would be triangular in shape and the area or size of the triangle would be largestrat the center of the chip and would decrease in area towards the ends as the chip is elongated; furthermore the chips would be of varying length, the shortest chips being cut adjacent the center of the ingot and the longest adjacent the outer peripheral edge and, due to the fact that the cutter rotates in one plane, and the ingot rotates in a plane at right angles to the cutter the chips are curled or substantiallycres cent shaped with minute cracks extending crosswise of the chips so that each chip tends to break laterally into. tiny, almost powder-size particles, a large percentage of which are actually powder-size particles which may and are screened out before the remainder is subjected to grinding or attrition for further reduction.

To prevent oxidation of the magnesium metal, or danger of fire during the cutting operation,

theJower endof the ingotandthe rotary cutter is maintained submerged in agsubstantially-non'r volatile liquid free. from oxygem A satisfactory liquid is kerosene. This liquid is-maintainedin constant circulation through a.tank,xnotshown, which surrounds the cutter and lower endi of the ingot and through a filter or the like and-as such reduces fire danger to a minimum and at the same time serves to carry thecut metal to the filter for removahgrading, grinding, etc.

It was previously stated that the; feed shaft,

was fed downwardly at a predetermined. rate and that this-rateto a: large extent isi-one of: the factors that control the size of the chips. cut away from the lower end of theingot bar by the cutter B. For instance, if the rate of feed-is increased, the chip will. be larger as the amount of, metal feed towards the cutter'is greaterand conversely with decrease inathe. rate of feed the chips will besmaller' as the ingot bar is fed; to-

m a new ingot is beinginserted. While-these and ward the cutter at a slower rate and-the amount Y of metal to be cut away is less. Hence, aerate of feed is selected whichproduces chips or particles of the most desirable size, Even so it is obvious that the cutting points t2 on the: cutter will in time gradually become dull and in fact so dull'that if the feeding rate isconstant there would be a tendency to jam the end of the ingot bar against the cutter as the dull cutting points would not be able to: cut the metal awayas; fast asthe predetermined feeding rate demands; It is for this reason that a beltdrive is employed in connection with the. pulleys 9a and Ma. Belt 23a drivingthe pulley 9a in particular will tend to slip and squeal when the cutter becomes too dull thus slowing down: the. rate: of revolution of the feed shaft to a. point where downward feeding. of the feed shaft is substantially stopped thereby not only preventing jamming or excessive pressure of the ingot baragainst the'cutter, but also warning the operator as the sound or squeal produced by the slipping belt. is sufficie'ntly audible to give the operator a. timely warning of the fact that the cutteris becoming too dullto emcientlyi perform-the work orrat leastthat'it is time to change cutters; as the feeding ratewill become so: slow. that the output of the machine will be substantiallydiminished.

Another factor that shouldbe' considered in the production of small chips isithev fact: that the cutter is not operated atv ordinary slow milling machine speeds; conversely its revolutions: are up around two thousand R. P. while theingot revolves at about sixty R.- P. Inasmuch as the ingot bar E- may be two and three feet or more in length and is. secured when placed in the machine at the upper end only, it has: been found advisable to guide the end ofJth'e. ingot bar which engages the rotary cutter as there is otherwise a tendency towards eXcesssvibraition and chatter. A form of guide. which. may be likened with a steadyi-rest is. shown in. 7 and 8; It consists of a pair of arms. 65 andi-BB pivotally secured at one end as at.6:-7 and con!- nected by a spring 68.. at their opposite ends, On the innercdge of each of said; arms approximately midway of' their length is a recess presenting three surfaces E9; 10 and. H. These faces engage the. exterior surfacewofai the ingot adjacent its lower end and as. the engagement other. features of the: machine haveibeen more or less specifically described, and illustrated, I nevertheless; wish". itv understood, that, changes maybe resorted towithin thetscopeof. the appended claims, and that the materials and finish of the various parts-employed may be changed as the experienceof; the. manufacturer may die.- tate and as varying, conditions'or use'may demand. I j

Having. thus described and illustrated my in"- vention, what I claim and wishto secure by Letters Patent; is:

1. In a machine. of; the: character described,

a rotary cutter, a chuck to secure an ingot, said chuck and ingot being disposedzat right angles to the cutter, means for rotatingthe chuck and ingot, means for gradually. advancingrthe. chuck and ingot-toward 'thezcutter, and means for, automatically stopping the advance when; the chuck reachesa. predeterminedposition adjacent the cutter.

2. In. a: machine of: the characters described, a'rotarycuttema chuck to secure an ingot, said chuck and ingot being disposed atiright angles to the cutter; means for rotating the chuck and ingot, means. for. gradually advancing the. chuck and. ingotv toward. the cutter, means" for auto matically: stopping the advance when: the chuck reaches a predetermined;position adjacent: the cutter, and means for. maintaining .the ingotin contactwith the. cutter and'under apredeterminedpressure as the chuck and ingot are; being 4; In a-.machine of; the. character'described,

. a rotary cutter, a chuck to secure an ingot, said chuck and: ingot being: disposed. at right angles to the cutter, means. for rotating thechuck and ingot, means-for: gradually advancing" the chuck and ingot toward. the cutter, means for automaticallystopping the advance when the chuck reachesaqpredetermined position adjacent the cutter; means: for automaticallyretracting the chuck to a leading position,. and means for auto- 'matical'ly stopping rotation. of the-chuck when it reaches the loading position to permit removal of what'is left of a previous ingot-and insertion of another ingot: to be. out.

' J OI-IN: FRED- RAGENDARM.

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