US2739427A - Tumbling mill - Google Patents

Description

arch 27, 1956 N. RANSOHOFF 2,739,427

TUMBLING MILL Filed March 1, 1954 '7 Sheets-Sheet l INVENTOR.

ATTOENEYS.

March 1956 N. RANSOHOFF 2,739,427

TUMBLING MILL Filed March 1, 1954 7 Sheets-Sheet 2 March 27, 1956 N. RANSOHOFF TUMBLING MILL.

7 Sheets-Sheet 3 Filed March 1, 1954 F F O H O S N A R N TUMBLING MILL 7 Sheets-Sheet Filed March 1, 1954 Arron/5Y5.

March 27, 31956 N. RANSOHOFF TUMBLING MILL 7 Sheets-Sheet 5 Filed March 1, 1954 NVEN TOR.

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March 27, 3956 N. RANSOHOFF TUMBLING MILL 7 Sheets-Sheet 6 Filed March 1, 1954 N V EN TOR.

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TUMBLING MILL Nathan Ransoholf, Cincinnati, Ohio, assignor to N. Ransohotf, Incorporated, Hamilton, Ohio, a corporation of Ohio Application March l, 1954, Serial No. 413,376

13 Claims. (Cl. 51-164) partment or drum mounted for rotation about a horizontal axis; the parts to be treated are confined in the compartment together with a mass of abrasive fragments or particles, sometimes called stones. During rotation, the commingled mass of stones and metal parts are agitated together in the compartment to enable the stones to clean and polish the surfaces of the metal parts by an abrasive scrubbing action. A machine of this character is disclosed in the patent to Nathan Ransohoff, No. 2,299,032, issued on October 13, 1942.

The invention is disclosed in relation to a tumbling mill of this general class which is constructed to utilize a power driven separator at the discharge end which separates the treated metal parts from the stone as the mass is discharged from the machine. At the charging end, a power loader preferably is utilized to elevate and charge the batches of parts into the charging end of the machine. The power loader and separator enable the machine to treat the parts at a rapid production rate and are of particular advantage in treating relatively small parts.

One of the primary objects of the invention has been to provide a tumbling mill particularly suited for rapidly treating relatively fragile, precision made metal parts which require a cleaning and polishing treatment but which must be carefully protected against the possibility of being nicked or otherwise marred during treatment.

The present machine is intended particularly for the surface treatment of the blades or vanes for the rotors of jet engines, consisting of relatively thin elongated metal plates requiring a smooth surface finish which is free of flaws or nicks. In order to pass inspection after being treated in the tumbling mill, the edges of the vanes must be smooth and free of any measurable nicks or other irregularities. This obviously is a critical problem since the edges of the blades are delicate and are most likely to suffer damage during tumbling.

A certain amount of collision between workpieces is usually associated with the operation of a tumbling mill; however, as a practical matter, this is of no consequence in treating ordinary metal parts because of the shape of the parts. The impacts occur usually as the parts are charged into the machine and as they are discharged from it; during the actual tumbling operation, the parts are suspended in the abrasive mass and thereby protected. in the present machine, means have been provided for gently sliding or skidding the parts along as they are charged into the machine and as they are discharged from it; therefore, at no point during treatment are the parts likely to be damaged by colliding with one another or striking the surfaces of the machine. The machine is therefore adapted particularly for jet blades and other 2,739,427 Fatented Mar. 27, 1956 metal parts having thin section or edges which must be protected.

Briefly, the present tumbling mill constitutes a generally cylindrical tumbling chamber having a charging cone at one end for feeding in the parts and a work clelivery structure at the opposite end for discharging the work and stone after treatment. During the tumbling operation, the mill is rotated in a given direction for a tumbling period; thereafter the direction is reversed to discharge the parts. The type of abrasive material utilized depends upon the particular requirements of the parts being treated, for example, it may consist of particles of stone, ceramic, Carborundum, or aluminum oxide.

For the purpose of sliding the parts gently during transfer from the charging cone to the tumbling chamber, the charging cone of the present machine has generally convolute related surfaces which, during rotation, provide a ramp action, thereby to elevate the parts and skid them gently into the tumbling chamber without impact. To discharge the parts upon reversal of rotation, the parts are elevated by a spiral chute leading from the periphery of the tumbling chamber to a discharge drum at the discharge end of the chamber. The spiral chute during rotation receives the parts and, again by a sliding action, elevates the parts without collision and deposits them gently in the discharge drum. The drum includes a spiral conveyor which advances the parts and abrasive particles through the drum and deposits them upon an adjacent power separator which separates the parts from the abrasive elements.

Another object of the invention has been to provide, as a component part rotating with the tumbling mill, an apparatus which operates in conjunction with a power separator to return the separated abrasive elements into the tumbling mill for re-use. For returning the abrasive particles, there is provided upon the discharge end of the tumbling mill a concentric collector ring which has a diameter substantially greater than the diameter of the machine. This ring rotates with the machine and its lower portion passes under and intercepts the stream of separated abrasive issuing from the separator. During rotation, the abrasive particles are elevated and discharged back to the machine by a series of radial chutes attached to the rear wall of the ring and rotating with it. The abrasive is charged into the outer ends of the chutes as they rotate through the mass in the lower portion of the ring; the abrasive flows by gravity during continued rotation.

A further object of the invention has been to provide a power loader at the charging end of the mill which elevates the parts and slides them gently into the open end of the charging cone in a positive manner without subjecting the parts to impacts. The power loader includes a vertically movable hopper which projects toward the cone, the hopper being arranged to remain in a horizontal plane during its elevating motion and to pivot to an inclined, discharge position at its upper level of travel. In its horizontal position, the hopper moves vertically in a plane spaced from the end of the cone for clearance. Upon pivoting to its inclined position, the end of the hopper projects into the cone so as to guide the parts in a positive manner into the cone. Prior to being lowered, the hopper first pivots back to its level position, thus retracting the projecting end back to its former plane for downward movement clear of the end of the cone.

Various other advantages of the invention will be more .fully apparent from the following detailed description taken in conjunction with the drawings.

In the drawings:

Figure l is a general side elevation of the tumbling mill J showing its association with the power loader and separator.

Figure 2 is an enlarged sectional view taken longitudinally through the tumbling mill.

Figure 3 is an end view taken at the charging end of the tumbling mill, illustrating generally the structure of the loading cone and its component parts. H

Figure 4 is a sectional view taken on line Fig ure 3 further illustrating the charging cone and charging; scoop.

Figure 5 is a sectional view taken on line 5 5, Figure 3, further detailing the cone and scoop structure;

Figure 6 is an end view similar to Figure 3, with the loading cone partially broken away to illustrate thesc'oop structure.

Figure- 7 is a fragmentary sectional View taken from Figure 2, illustrating the work discharge drum and associated parts at the discharge end of the machine.

Figure'S is a sectional view taken on line 8 8,- Figure 7, illustrating the spiral chute which elevates" the work from the tumbling chamber and delivers it to the discharge drum.

Figure 9 is an enlarged fragmentary sectional view taken from Figure 7, detailing one of the radial stone return chutes which advance the stones back to the tumbling chamber.

Figure 10 is an enlarged fragmentary view taken along line 10=- 10 Figure 7, further detailing the arrangement of the stone-return chutes.

Figure ll is a sectional view taken on line ll l-l Figure 7, illustrating the head of the tumbling chamber. at the discharge end and the respective openings therein which lead to the spiral work discharge ramp and stone return chutes.

Figure 12 is an end view of the discharge and of the tumbling mill illustrating the stone collector ring and stone return chutes thereof.

Figure 13 is afragmentary perspective view of the receiving end of one of the stone return chutes'of thecollector ring.

Figure 14 is a fragmentary perspective view of the delivery end of one of the stone return chutes.

Figure 15 is a side elevation of the power loader which islocated at the charging end of the tumbling mill.

Figure 16 is an end view of the loader as projected from Figure 1-5.

Figure 17 is a sectional view taken online 17-17 Figure 15, detailingthe hopper and its vibrating bottom.

Figure 18 isa sectional view taken on line 18-48 Figure 15, detailing the cable guide along one side of the hopper.v

Figurel9 is an enlarged side view showing amodified tumbling mill in which the stones are separated in the discharge cone as distinguished from the power separator illustrated in Figure 1.

General ari-m'zgme'nt and operation Referring to Figure l, which illustrates the tumbling mill 10 installed for production operation, the partsto be treated are fed into the machine by the power loader The loader elevates batches of parts and slides them into the open charging endofindicated generally at 11.

the mill. The-tumbling mill is rotated in a given direc-- tion during the tumbling operation; thereafter it is rotatedin the reverse direction for discharging the finished parts to a power separator indicated generally at 12. Atthis point, the treated parts,.together with thestones or other abrasive elements, are discharged upon the separator which returns the stones back to the mill for re-use and concurrently advances the finished parts to adischarge a sloping surface which causes the material to gravitate inthe-desireddirectionduring rotation of the mill. Upon operation of the power loader, with the machine rotating in tumbling direction, the parts are charged into the loading cone indicated at 13 and are advanced from the cone to the tumbling chamber 14 by a scoop structure within the cone. A mass of commingled parts and stones as indicated at 15 in Figure 2 is maintained within the tumbling chamber during the tumbling treatment.

Joined tothe opposite end of the tumbling-chamber is a, collector chamber 16 which includes a work discharge drum 17 (Figure 2) for conveying the work and stones-from the tumbling chamber to the separator upon reversal of rotation to discharge direction. During rotation in discharge direction, the separated stones are fed back from the separator to the collector chamber which serves as accumulator for the used stones. After all of the parts and stones are conveyed from the tumbling chamber'a'nd separated, the mill is again rotated in the tumbling direction. The stones which have been accumulated in the'collector chamber are now fed back into the tumblingflchamber and, at the same time, a freshbatch of 'pa'rts' is introduced into the tumbling chamber by way of the charging cone 13.

As indicated in Figure l, the tumbling mill is rotatably supported by rings 18-18 which are tracked upon flanged rollers 20' mounted for rotation at opposite sides of the mill". The driving system by which the mill is rotated is well known in' the art. In the present disclosure it comprisesan electric motor and speed reduction unit 21, the motor being mounted upon a frame 19. A sprocket chain 22-, which meshes with a sprocket ring 23 (Figure 2) on the tumbling mill, completes the driving connection 'with asprocket of the speed reduction unit.

A's the Work is charged into the cone, the tumbling mill 'is-rotated in tumbling direction as indicated by the arrows'in Figures 3 and 8. Upon being introduced into the cone, the parts slide down the sloping wall of the v'ersal of rotation to discharge direction, the parts and stones pass through the opening 23 in the rearward membrane or head 30 of the tumbling chamber (Figure 11). This opening communicates with a spiral ramp or chute 31; thechute' having its opposite end communicating with thewor-k discharge drum 17 as shown in Figures 7 and 8.

The discharge drum is provided with a spiral vane 32 which advances" the parts and stones through the tube to=thevseparator 12 as described in detail later.

For the purpose (if-recovering and conveying the stones b2iGkjt0"th tumbling chamber, the forward end of the collector chamber 16 includesastone c'ollectorring 33. therseparator 12 being provided with a trough 34"having ansend projecting above the ring 33. As best shown in- Figure 12, the ring includes a series of radial stone return chutes .35 which pick up the abrasive particles from the lower portion of the ring during rotation of the mill in either direction. During rotation, the chutes advance the m'ateriafthrough openings 36 formed in the wall 37 of the ring and into the collector chamber 16.

After passing into the collector chamber, which is slightly-conical for this purpose, the stones advance back teward'the he'ad 300i the tumbling chamber where they are-picked up by a second series of radiai stone return" chutcs'38; These chutes pick upthe stones and deliver them through the-openings ll-into the tumbling chamber for-:re-use,:-but only when the mill is rotating intum'oling direction.=.

Brieflyitherefore the comminglcd mass of abrasive and parts isqagitated in the tumblingcharnber during rotation in-lhe tumbling direction, andis discharged upon the separator during reverse rotation. At this point the treated parts are separated from the stones which concurrently are fed back into the collector chamber where they advance back to the tumbling chamber when the direction of rotation is again reversed to tumbling. During both the charging and discharging operations, the parts are advanced under carefully controlled sliding motions to protect the parts from impacts which lead to damage.

Charging cone As noted earlier, the parts to be treated are charged into the loading cone 13 by the hopper of the power loader 11, which moves vertically and pivots to the position shown in broken lines in Figure 1 to elevate and transfer the parts to the cone. As best shown in Figures 2 to 6, the open end of the cone is delineated by a lip 41 to prevent any of the parts from dropping from the cone after they are loaded into it. As the cone rotates in tumbling direction, the parts gravitate down the sloping surface of the cone until they contact the flow plate 42 which controls the flow of workpieces to the charging scoop 25. The flow plate includes the opening 24 for passage of the work parts into the charging scoop, the parts being elevated and gradually advanced by the scoop through the opening 26 of membrane 27 into the tumbling chamber.

The flow plate and scoop are fabricated from sheet metal suitably configurated to fit within the cone, the parts being attached preferably by welding as indicated later. As best shown in Figures 5 and 6 the flow plate includes a fiat portion 43 which is located at right angles to the axis of rotation in a plane spaced outwardly a substantial distance from membrane 27. As viewed in tumbling direction, the flat portion 43 forms the leading end of the flow plate; a sloping portion 4-4, approximately half the area of the plate, forms the trailing portion. The sloping surface 44, combined with the sloping surface of the cone, guides the parts in a smooth sliding path toward the opening 24 leading to the scoop.

Opening 24 is formed in an area overlying both the leading and trailing edges of the flow plate; hence the leading or pickup edge of the opening, as indicated at 45, is disposed outwardly a substantial distance from the trailing edge 46. During rotation in tumbling direction, as indicated by the arrow, the parts collect in the lower portion of the cone in contact with the fiat wall portion 43, then follow the sloping surface 44 as the opening rotates in its orbit below the axis of rotation. As the leading edge 45 passes through the mass of parts and begins to move upwardly in its orbit, the parts are trapped in the scoop 25.

As best shown in Figure 4 in its upper position, the leading portion 47 of the scoop slopes downwardly from the flow plate toward the lower edge of the opening 26 leading to the tumbling chamber. As the leading edge 45 passes through the mass of parts, the portion 47 assumes an angle generally the reverse of that shown in Figure 4; upon passing the axis of rotation, the plane of the scoop surface becomes generally parallel to the axis of rotation. Thereafter, as the portion 47 continues to rotate upwardly with the parts trapped in it the angle of its surface progressively changes to that shown in Figure 4, causing the parts to slide downwardly through the opening as indicated by the arrows (Figure 4). The parts are thus skidded through the opening as soon as the pitch of scoop portion 47 becomes suficiently great; this occurs at some point during rotation above the axis, usually before the portion 47 reaches the maximum slope shown in Figure 4.

As best shown in Figure 6, the scoop is generally convolute and its leading end 48, which is welded to the cone, is generally parallel to the axis of rotation. From the leading end, the scoop curves from the periphery of the cone upwardly toward the axis of rotation. Thus upon being trapped in the leading portion of the rotating scoop, the parts begin their elevating motion toward opening 26.

The inner edge of the scoop, as indicated at 50 in Figure 5, lies flush against the surface of membrane 27 to which it is welded. As shown in Figure 6, the scoop partially surrounds opening 26. The outer edge of the scoop, as indicated at 51, corresponds to the contour of the flow plate to which it is welded. As best shown in Figure 6, the trailing portion 49 of the scoop is generally flat and is disposed in a sloping plane substantially corresponding to the slope 4'7 shown in Figure 4. The trailing end 52 of this portion contacts the surface of the cone at an angle to the axis of rotation (due to the slope of the trailing portion 49) and is welded to the cone as indicated.

Referring to Figure 2, the flow plate and scoop are shown in a position corresponding to the section taken along line :-5 of Figure 3 but with trailing portion 49 in elevation. From this view, it will be seen that the parts will also flow inwardly across the end 52 of the scoop, as indicated by the arrow, upon rotation in the discharge direction. In other words, the trailing end, which then becomes the leading end of the scoop, will also advance parts along the sloping portion 47 of the scoop toward the opening 22: The scoop provides more efficient collection and advancement of the parts during rotation in the tumbling direction; however, during discharge rotation, the scoop is effective to return any parts to the tumbling chamber which may happen to fall through opening 26 during tumbling treatment or discharge. It will be seen therefore that the scoop provides ramp surfaces which are efiective to slide the parts smoothly into the tumbling chamber during rotation in either direction.

Work discharge After a timed tumbling period, the direction of rotation is reversed in order to advance the mass of treated work and abrasive from the tumbling chamber 14 to the discharge drum 17. As the tumbling chamber rotates, the mass of work and abrasive is in contact with the rearward head or membrane 3% which includes the opening 28 leading to the receiving end of the spiral chute 31 previousiy mentioned. This chute resides adjacent the opposite side of membrane 3% and its upper or discharge end communicates with the end portion of the work discharge drum 17, as best shown in Figure 8.

Referring to Figure 2, it will be observed that a portion of the spiral chute is offset inwardly from the plane of membrane St} to provide space for the radial stone return chutes 33 which extend from the periphery of the collector drum to the central stone return opening 49, previously mentioned. As best shown in Figure 2, the chutes 3t project through the end portion of the work discharge drum 17 but there is no communication between the chutes and the portion of the drum through which they project.

As viewed in Figure 8, the receiving opening 28 extends upwardly from the periphery of the tumbling chamber and is sufiiciently large to permit passage of the parts into the spiral chute during rotation in the tumbling direction. The chute is generally square in cross section as delineated by opening 28, and includes an inclined end wall 53 which connects the end of the chute to the opening. The chute section at the opening is in the form of a box 54, consisting of side walls 55-55 and a back Wall 56, the edges of the side walls being welded directly to the surface of head 39 around the edges of opening 23. The box section and chute proper blend together and spiral away from the surface of head 3% (Figure 8). Interposed between the box 54 and chute 31 is connecting chute 57' which inclines away from the plane of membrane 30 to provide space for the stone return chutes as noted above. The inclined connecting chute 57 and spiral chute 31, being spaced from the membrane 30, are provided with a forward wall 58 (Figure 7).

The discharge end of the spiral chute blends into an opening 60- communicating with the discharge drum asbest shown in Figure 8. As the tumbling chamber rotates in the discharge direction, the parts together with the abrasive particles, enter the receiving opening 28 and pass into the spiral chute where they are elevated toward the opening 60 of the discharge drum. In other words, the spiral chute defines a ramp having a gradual slope, such that the parts which are caught in the rotating chute are elevated to the discharge drum by a sliding motion. Upon reaching the discharge cone, the parts slide from the surface of. the chute to the interior of a cone 61 without any abrupt change in their direction of motion. Cone 61 forms a part of drum 17 but its slope is reversed and considerably steeper. For assembly purposes, the two cones are flanged as at 62 and are attached together by bolts 63 passing through the flanges.

Referring to Figures 7 and 8, it will be noted that the surface of the spiral chute blends smoothly with the internal surface of cone 61 such that the parts slide smoothly from the surface of the spiral tube to the cone as the delivery end of the chute passes below the axis of rotation in its orbit. Upon being deposited in the cone 61, the parts slide forwardly toward the end of discharge drum 17 because of the slope of the cone. Within the work discharge cone is a spiral conveyor vane 32 for conveying the parts toward the discharge end of the drum.

During treatment in the tumbling chamber, the parts are suspended in the abrasive mass and suffer no damage; however their surfaces must be protected from being nicked or otherwise damaged during discharge since parts are no longer suspended in the mass. In the conventional tumbling mill, there is a natural tendency for some of the treated parts to drop from the retrieving scoop or other member during rotation, such parts usually falling back into the tumbling chamber. Ordinarily this presents no special problem since the shape of the parts allows them to absorb such impacts without damage.

As explained earlier, the present machine is intended particularly for handling delicate parts such as rotor vanes for jet engines and similar parts which are rejected event if slightly nicked or scratched. The spiral chute 31 and its cooperating feed cone 61 provide gentle but positive advancement of the parts from the tumbling chamber to the discharge drum. When rotation progresses to the point where the work parts enter the cone opening 60, the parts slide smoothly into the cone and axially away from the opening, as indicated by the arrow in Figure 7. Accordingly, as rotation continues, the work parts have no opportunity to hang up at or near the delivery end of the chute and to drop back down the chute towards the receiving opening as rotation continues. Otherwise expressed, the cone 61 forms a trap to convey the parts down its slope and away from opening 60 as soon as the parts enter the cone. In actual practice, it is found that none of the parts escape after they enter the spiral chute; instead they are skidded along the ramp surfaces of the chute and cone and have no opportunity to drop out at any point during rotation.

Upon sliding down cone 61, the parts and abrasive fragments are caught in the leading end of spiral con veyor vane 32 and advanced toward the separator 12 as noted earlier. It will be noted in Figure 2, that the vane 32 is relatively high at the rearward end of drum 17 and that the vane decreases progressively in height toward the delivery end. The lead of the vane increases progressively towards the delivery end of the drum such that the parts advance at an increasing rate of speed. Accordingly, the mass of parts and abrasive fragments, which accumulates at the inner end of the cone, is delivered in a continuous stream to the separator 12 where the parts and abrading elements are separated from one another.

Separator The separator shown in Figure l is a commercial productand its exact structure is not essential to the present smicture-andoperation is considered necessary tdacbin? plete understanding of the'invent-ion. As the mixtureof' workpieces and stones drop from the delivery end' Of drum l7, the-stream. falls by gravity upon the receiving trough -ofthe separator. In order to advance'thei parts, the trough is" inclined downwardly and is also vibrated by an electric vibrator or the like (not shown).

As the stream of parts and stone fragments approach the end of trough 65, the metal parts are attracted to pulley 67 which is magnetized. A moving conveyor belt 66 is trainedover the pulleys 67 and 68. The parts which are attracted-to pulley 67 contact the conveyor belt and are thus elevated and conveyed upon the, belt. The pulleys are rotatably mounted'upon the frame 70'of the separator. Rotary motion is imparted to pulley 67 by an electric motor 71 connected to the pulley by a sprocket chain drive 72.

The conveyor belt is advanced at a rate of speedconsistent with the rate of discharge of the tumbling mill and the parts are conveyed upon the upper run ofthei belt in the direction indicated by the'arrow. As the parts reach the delivery end of the conveyor belt, they, drop from it by gravity since pulley 68 is not magnetic. From this point, the parts are conveyed from the machine in finished condition.

The stones or other abrasive particles, which are of nonmagnetic material, continue advancing down' the vibrating trough 65 and are discharged upon the stone return trough 34 previously noted. This trough is in clined downwardly in reverse to trough 65 and its lower or; discharge end 73 projects partially into the lower por-- tion of the collector ring 33. This trough is'likewisevibrated by an electric vibrator or other means to facilitate theadvancement of the stones. Upon reaching the collector ring, the stones are advanced back to the turnbling chamber by the radial stone return chutes, as ex-' plained in detail later.

According to the present disclosure, the separator is utilized to serve several tumbling mills, the separator being provided with flanged wheels 74 which ride upon the tracks 75 extending transversely across the discharge ends of several tumbling machines. The separator may be provided with an electric motor 76 connected by. a sprocket chain drive 77 to the wheels for propelling the separator relative to the tumbling machines.

In order to prevent interference between the ends of the troughs 34 and 65 and the parts of the tumbling. mill which they'interfit, the'troughs are pivotally mounted upon theseparator frame. The troughs thus may be swung to positions which clear the projecting ends-0E thefldischarge drum andthe stone collector ringlwhen the separator is shifted from one tumbling mill toanothers In the'eventthat the nature of the work requires the" use of stars,- slugs, or the like, fabricated from a magnetic. material, or if the workpieces are not magnetic, then a separator utilizing a difi'erent principle of operation is utilized. By way of example, a screen type separator may be utilized which has a mesh suitable to separate. the abrasive particles from the relatively larger work parts. In this instance a return trough'similarto'trongh- 35 preferably is utilized to return the abrasive particles" to' the collector ring 33.

Stone return The collector ring 33 is considerably larger in diam eter than the collector chamber and is mounted upon: the end of the collector chamber by a series of bolts 78" (Figure 2) passingthrough a flange Bil-into the end wall 37 ofthe ring. The annular wall 81 of the ring, which accumulates the returning stones, is generally conicaland is joined by' a cylindrical wall 82 which ioins end wall 37. The forwardedge of the conical wall includes; a lip 83 which confines thereturning. stones asthey gravitate toward the end wall during rotation of the ring. The returning stones are elevated from the lower portion of the ring by the radial chutes previously noted.

Described with reference to Figures 12 to 14, there is provided a set of six stone return chutes 35, the chutes being mounted radially upon the end wall 37. Each chute comprises a pair of spaced side walls 84-84, joined by a front wall 85. The end wall 37 of the ring forms the fourth wall of the chutes; the side edges of the side walls being joined to the wall by welding as at 86. The outer end portions of the side walls 85 terminate in spaced relationship to the periphery of the cylindrical wall 82 (Figure 12) to provide the stone receiving openings 87-87 at opposite sides. The inner ends of the chutes communicate with the openings 36 of wall 37, each chute having an inclined end wall 38 which directs the stones through the openings to the interior of the collector chamber.

As shown in Figures 12 and 13, each chute is provided with a bafiie 90 which extends parallel with the side walls 84 in a plane intermediate the two side walls. The outer end of the bafiie joins the surface of the ring and the inner end of each baflle terminates short of the inner end of the chute. During rotation of the ring, a portion of the stones in its lower portion are deflected by the endwise portion of the baffle through the openings 87 into the chute. As the chute assumes an inclined position during rotation, the stones slide by gravity down the chute into the collector chamber where they collect in the lower portion to be elevated by the second set of return chutes 38 to the tumbling chamber.

It is to be noted that the baffles 94 cause the stone return chutes to collect and return the stones during rotation of the machine in tumbling or discharge direction. In other words, in either direction of rotation, the stones enter one or the other of the openings 87 and are guided into the chute by the baffles.

In order to prevent any of the stone fragments from bouncing from the collector ring, there is provided a deflector disk or baffle 91 in the plane of the lip 83. The disk is attached to the end of the discharge drum and delineates an annular space to accommodate the end of trough 34 which projects into the ring.

As best shown in Figures 7 to 11, the stone return chutes 38, leading from the collector chamber to the tumbling chambers are generally similar to the chutes 35 except that a set of three is utilized. The chutes 38 are arranged to return the stones only during rotation in the tumbling direction and to idle during rotation in the discharge direction. After all of the workpieces and stones have been discharged and the machine is reversed to tumbling direction, the mass of stones which has accumulated in the collector chamber is fed back into the tumbling chamber.

Referring to Figure 8, each chute 38 comprises a pair of side wall 92-92 welded upon the surface of membrane 30 and enclosed by a cover plate 93. The side wall 92, which is at the leading side of the chute during rotation in tumbling direction, has its outer end spaced from the periphery of the collector chamber to provide the opening 94. The opposite side wall extends outwardly to the periphery of the chamber, the arrangement thus providing a single entry chute. Therefore, during rotation in the tumbling direction, the stones enter the openings 94 as indicated by the arrow in Figure 8, and during rotation in the opposite direction the chutes pass through the mass without trapping any stones.

As explained earlier, the inner end portions of the chutes 38 pass through the wall of cone 61 but are not in communication with it. An end wall 95 is mounted within the cone at the plane of the chutes to close off this area. The inner ends of the radial chutes adjoin one another at the central axis of the machine and the end of each chute is provided with an inclined end wall 96 which is generally V-shaped as viewed in Figures 9 and 10. The forward edges 97 of the end walls all radiate from the axis of the chamber and interfit to form a spider, as viewed in Figure 11, subdividing the discharge opening 40 of head 30. The inclined end walls 96 direct the stones through the opening into the tumbling chamber and prevent stones from tumbling back through an adjacent chute during rotation.

Power loader The power loader (Figures 15 to 18) in general comprises a base structure 98 supporting a vertical frame 100 which has a vertically movable hopper 101 tracked for vertical movement within it. The hopper is connected by a cable 102 to a standard power hoist 103 mounted at the top of the frame. The forward end of the hopper is in the form of a discharge chute 104, the outer end of which is normally spaced away from the end of the charging cone (Figure 1). Upon reaching its elevated position, as indicated in broken lines in Figure 15, the hopper, which is now adjacent the open end of the charging cone, swings about a pivot point to an inclined discharge position. This motion projects the end of the chute within the open end of the cone, as indicated, causing the parts within it to be fed into the cone.

in order to feed the parts, the hopper is provided with a false bottom 105 (Figure 17) which is vibrated by a power operated vibrator 106 connected to it. The vibration, combined with the inclination of the false bottom, causes the parts to slide down the slightly inclined surface upon which they are resting. The vibrator may be powered electrically or otherwise and is not disclosed in detail since it is a standard commercial unit.

Described in detail, the frame 100 comprises a pair of vertical channel members 107-107 fabricated from structural steel and having a cross beam 108 extending across the top of the frame. The ends of the beam which are joined to the upper ends of the channels are braced by the gusset members indicated at 110. The hoist unit 103 is attached to the beam by suitable hangers indicated at 111. The several structural members are attached together preferably by welding.

The hopper is pivotally mounted upon a vertically movable carriage 112, having sets of rollers 113 which are tracked at opposite sides between the flanges of the channels 107. The rollers are rotatably journalled upon axles 114 which are attached to the side members 115-115 of the carriage. The carriage is U-shaped, the side members having their lower ends joined by a cross beam 116 (Figure 16). The lower portion of the carriage is provided with a pair of forwardly projecting brackets 117-117, one for each side member, the brackets located immediately above beam 116; the hopper is also provided with downwardly projected brackets 118-118. The respective pairs of brackets are pivotally connected together at their outer ends by the pivot shaft 120.

The hopper is formed of sheet metal and is preferably of welded construction. It includes a pair of spaced side Walls 121-121 which, as viewed from the side, have an upwardly inclined lower edge, joined by a curved bottom plate 122 which forms the discharge chute. The false bottom 105 is similarly curved and nests within the inclined bottom plate in slightly spaced relationship (Figure 17). To prevent particles of material from falling into the space beneath the false bottom, its upper edges are protected along opposite sides by the angular flanges 123-123 which are welded to the interior surface of the side walls 121. The flanges overhang the upper edge portions of the false bottom, clearance being provided be tween the two surfaces to allow the vibratory motion. .1" he rearward end of the hopper may be provided with a door 124 which is hingedly connected as at 125 to a panel 126 enclosing the lower portion of the hopper. The door includes latches 127 for looking it in closed position.

As shown in Figure 16, the cable 102 is connected at its -lowerend to a cross bar or singletree 128- wh'ichapplies equa'l cable pull upon the oppositesidesof-the hopper as'itds' elevated and tilted. The cable is anchored at the center of the bar as at 129 and a pair of equalizing cables 130--130is anchored upon the opposite end portions of the'b'ar as at 131. The lower ends of the equalizing cables are a'nchored as at 13?; upon the projecting opposite ends of a cross bar 133 which extends across the bottom-of the hopper, the bar preferably being welded to the bottom of the hopper. The equalizing cables are normally confined" in the-curved cable guides 134-334 which are WeldedupOn-the'side plates at opposite sides of the hopper (Figure 18').

The hoistunitincludes the usual reduction gearing in driving 'c'onnection with a cable drum, and upon being energized, elevates the hopper to the position shown in' broken-lines; By reason of the shape of the hopper and its relationship with the carriage and cable, the major weight load 'is'carried in the rearward portion of the hopper-in-cantileverfashion relative to frame of the load distribution, the hopper tends to rotate toward the left, as viewed in Fgure 15, as its rearward end is hoisted free of the base 98 upon which it normally rests. However, the forward portion of the hopper is provided with a pair of guide pins 135, confined for vertical movement ina pair of vertical guide channels T36 attached to the channels 107. As the cable begins to elevate the hopper, thehopper tends to rotate about its pivot shatf however, this motion is restrained by the guide pins 135, causing'thehopper to remain in its horizontal portion as itis elevated.

The hopper remains in its horizontal position as the end of the chute passes the end of the loading cone. Upon reaching the discharge elevation, the upper rollers 113 engage a pairof stops 137-137 which areattached At this point, the

to the channels on opposite sides. carriage is stopped while the hoist continues elevating the hopper. This causes the hopper to pivot relative to the carriage'about the pivot shaft 120 until it reaches the inclined discharge position shown in broken lines. will be noted that the relationship of the pivot point to the plane of the hopper causesthe forward end of the chute to move forwardly and to project into the open end of the charging cone as it tilts. When the hopper reaches this position, the vibrator 106 is energized to facilitate the discharge of parts. Thereafter, the hoist is energized in the reverse direction, causing the hopper first "to assume itshorizontal position and then'to descend with the carriage to its loading position.

It will be noted that the cable guides '84 provide a rolling action with respect to the equalizing cables as the hopper swings to and from tilted position. The cable guides reduce the cable tension incident tothetilting operation, since the guides increase thecable angle at the elevated position, as indicated by the broken lines 162a in Figure 15. In the absence of the guides, the point of application of the tension would swing in an are about pivot shaft 120 and approach a dead center relation ship as-the hopper tilts.

The guide channels 136 referred to above, are in the form of angle irons which are attached preferably by welding to the side webs of the channels 107, such that the pin is confined between the flange of channel and the flange of the angle iron. The upper ends of the angle irons are joined by generally horizontal guide flanges 138 at opposite sides. The forward end of each horizontal guide flange includes an outer portion which slants downwardly as at 140 The adjoining endportionsof the vertical and horizontal guide structures are reinforced by the gusset plates l llat opposite sides, which are welded to the channels 107 and to the angle iron structures; It will be noted that the flanges of the'vertic'al a-ud'h'orizontal guides are connected together by a curvedflange-indicated" As=thehopper is elevated to the stops 137, and-while Because 12 still inho'rizontal position, the guide-pinsrea'ch a-po'si-" tion=above-the upper ends of the guides as indicated at 135a 'in-broken lines. As the hopper rotates about the pivot shaft 120 toward its inclined position, the 'pjns swing in an are about the pivotal axis to the second"position shownin broken lines at 1351;; Upon" reaching position-135i) the pin engages theinclined flange 140 of the guide, which thus provides a stop limiting' the angular position of the hopper. Uponreversal of" the hoist motor, the hopper swings back to level 'position'as' explained above, thereby causing the guidepins 135 to return to the plane of the vertical'guide'channels'136f and to reenter the guides as the hopper descends; The guide pin and guide channel structure is thuselfective to maintain the hopper in its horizontal position'in'a'positivc" manner until it reaches its upper or lower limit'oftravell" This prevents interference with the end of thecone' and possible damage to the equipment.

The loader preferably is provided withan automatic control'systern for regulating in sequence the operation of the hoist motor and vibrator. Thecontrol systenr follows conventional engineering practice" and is riot'dis closed in the drawings. A

the stream of workpieces and stone is advanced through the drum byythe spiral conveyor 32; As the stones'drop into the collector drum, they gravitate toward'the mam brane30 of the tumbling mill, there tobepicked upbyf.

the radial stone return chutes 38. This structure'includes' the spiral chute 31 and related structure, as'previously' describcdfor elevating the parts and stones from thev tumbling chamber to the discharge drum.

In the modified structure, a spray pipe 144 projects;

inwardly into the open end of the drum, the pipe being supported by exterior mounting means (not shown) The pipe is connected to a source of water pressure or treating" liquid, and'includes perforations suitable. toldirect jet streams'of liquid'upon the advancing parts and abrasive fragments. The liquid treatment is desirable in treating certain classes of work'and it is found to facilitate the dischargeof the parts and to dislodge any particles adhering'upon their surfaces.

After passing'through. the abrasive fragments. and work pieces, the liquiddrains into the collector chamber. For

draining the liquid from the collector chamber, the wall' of the chamber is provided with one or a series' of screened" openings as indicated at 145, the screen 146 bein'gkof amesh to restrain the abrasive particles. Since the work parts and stones are not discharged to the external'separator, the end ofthe collector chamber is closed oif'by the end wall 147. Y

The. modified machine operates upon the principles described earlier, except that the collector ring is omitted and the power separator is not utilized; However, the modified machine is intended tobe charged by thepower. loader in the manner described earlier. I

workpieces at a rapid production rate and of protecting;

the parts from being nicked or otherwisedamagediduring.

passage through the machine.

Having described my invention Lclaim:

1. In a tumblingimill having a generally-cylindrical. tumbling chamber rotatable about its longitudinaltaxis andiac'luding forwardand rearward end walls, ;the for-. ward end wall including a central charginglopening and the; rearward end wall including a rdischarg'e' .drumgpro jectingputwardly therefrom and having a discharge open The modified 1 structure provides the same advantagesof treating fragile.

ing at the periphery of the tumbling chamber; means for charging and discharging workpieces by a sliding action to and from the tumbling cha nber comprising, a charging cone mounted upon the forward end wall concentric to the charging opening thereof, the cone having an open outer end, the cone tapering outwardly from said open end toward the forward end wall, a vertical loader frame disposed adjacent the open end of the cone, said frame having a work charging hopper including a discharge end projected toward the open end of the cone and normally disposed below the cone, guide means connecting the hopper to the frame for vertical movement of the hopper in a fixed path spaced outwardly from the open outer end of the charging pivot means connecting the hopper to the guide means, the pivot means located below the discharge end of the hopper, hoist means mounted on the frame and connected to the hopper at a plane rearwardly from the pivot means, thereby to elevate the hopper to a position adjacent the opening of the cone and to swing the discharge end thereof downwardly in an are into the opening of the cone for sliding the workpieces into the cone, charging means in the cone including a scoop having opposite ends joined to the periphery of the cone and having a curved portion partially surrounding the central charging opening, said curved portion dispo ed at an angle to the axis of rotation, said scoop elevating the workpieces by a sliding action from the cone to said charging opening by rotation of the cone, and a spiral chute mounted externally upon said rearward wall and having an intake end in communication with the said discharge opening, said spiral chute having a delivery end communicating with the discharge drum, thereby to elevate the workpieces to the drum by sliding action during rotation of the tumbling chamber.

2. in a tumbling machine having a generally cylindrical tumbling chamber rotatable about its lorwitudinal axis, the chamber including forward and rearward end walls, the forward end wall including a central charging opening; means for charging workpieces by a sliding action through said charging opening comprising, a charging cone having an end mounted on said forward end wall concentric to the charging opening, the cone having an open outer end, the surface of the cone tapering out- Wardly from its open end toward the end wall, a flow plate mounted in the charging cone and having a portion disposed in a plane generally parallel to the end wall and spaced outwardly therefrom, the flow plate having a second portion which slopes inwardly toward the said end wall, the flow plate having an opening in the marginal portion thereof, said op ning rising from the periphery of the charging cone, said opening delineating a leading edge in the parallel portion of the how plate and a trailing edge in the sloping portion thereof, the taper of the cone and sloping portion of the how plate guiding the workpieces in sliding motion toward and through the flow plate opening during rotation of the machine, and a charging scoop mounted between the flow plate and said end wall, the charging scoop having a leading edge joining'the periphery of the cone, the scoop having a leading portion joining said leading edge which is generally convolute, the scoop having an outer edge joined to the flow plate around the edges of the how plate opening, the scoop having an inner edge joined to the end wall of the tumbling chamber around the edge of the charging opening, the scoop having a trailing end joined to the periphery of the cone, the axis of the convolute portion being oblique to the axis of rotation and providing a guide surface extending angularly to the axis of rotation from the opening of the how plate to the central charging opening of the end wall, the leading edge of the scoop, during advancement of the convolute portion below the axis of rotation, passing under the workpieces advanced through the flow plate opening, the convolute portion elevating and advancing the workpieces by a sliding action toward and 14. through the charging opening into the tumbing chamber during advancement thereof above the axis of rotation.

3. In a tumbling machine having a generally cylindrical tumbling chamber rotatable about its longitudinal axis, the chamber including forward and rearward end walls, the forward end wall including a central charging opening; means for charging workpieces by a sliding motion through said charging opening comprising, a charging cone hav-' ing an end mounted on said forward end wall concentric to the charging opening, the cone having an open outer end, the surface of the cone tapering outwardly from its open end toward the end wall, a flow plate mounted in the charging cone and having a portion disposed in a plane generally parallel to the end wall and spaced outwardly therefrom, the flow plate having a second portion which slopes inwardly toward the said end wall, the flow plate having an opening in the marginal portion thereof, said opening rising from the periphery of the charging cone, said opening delineating a leading edge in the parallel portion of the flow plate and a trailing edge in the sloping portion thereof, the taper of the cone and sloping portion of the flow plate guiding the workpieces in sliding motion toward and through the flow plate opening during rotation of the machine, and a charging scoop mounted between the flow plate and said end wall the scoop extending from the opening of the flow plate to the central charging opening of the end wall of the tumbling chamber, the scoop having a leading edge joining the periphery of the cone adjacent the leadingedge of the how plate opening, the scoop being generally convolute and having a trailing end joined to the periphery of the cone adjacent the trailing edge of the How plate opening, the axis of the convolute scoop being oblique to the axis of rotation of the machine, whereby workpieces entering the flow plate opening are elevated and advanced by the scoop in sliding motion toward and through the charging opening during rotation of the machine.

4. In a tumbling machine having a generally cylindrical tumbling chamber rotatable about its longitudinal axis, the chamber including forward and rearward end walls, the forward end wall including a central charging opening; means for charging workpieces by a sliding motion through said charging opening comprising, a charging cone having an end mounted on said forward end wall concentric to the charging opening, the cone having an open outer end, the surface of the cone tapering outwardly from the said outer end toward the end wall, a flow plate mounted in the charging cone and having a portion disposed in a plane generally parallel to the end wall and spaced outwardly therefrom, the flow plate having a second portion which shopes inwardly toward the said end wall, the flow plate having an opening in the marginal portion thereof, said i opening rising from the periphery of the charging cone,

, the periphery of the cone adjacent the leading and trailing edges of the flow plate opening, the scoop being generally convolute and having an inner edge joining the end plate and partially surrounding the charging opening thereof, the scoop having an outer edge joining the flow plate and surrounding the flow plate opening, the leading or trailing edges of the scoop advancing under the workpieces passing through the fiow plate opening depending upon the direction of rotation of the machine, whereby the scoop is effective to advance the workpieces by a sliding action through the charging opening during rotation in either direction.

5. In a tumbling machine having a tumbling chamber mounted for rotation about its longitudinal axis in charglog and discharge directions and having a rearward end wall including a coaxial discharge drum projecting outwardly therefrom, means for discharging material from the tumbling to the dischargedrum by a sliding action comprising, a spiral chute mounted externally upon said rearward end wall, the spiral chute being generally square in cross section in the form of a tube with the spiral convolution residing generally in the plane of the end wall, the end wall having an intake opening at the periphery of the tumbling chamber to receive the material in the chamber, a cone mounted externally of the end wall coaxial to the discharge drum, and having an end connected to the discharge drum, said cone tapering outwardly from the end wall toward the discharge drum, the said spiral chute having an open intake end corn municating with the said intake opening of the end wall and having an open delivery end communicating with said cone, the open delivery end of the chute located along the cone between the end wall and discharge drum, whereby the cone provides an outwardly tapered surface leading from the open delivery end of the chute to the end of the discharge drum, the portion of the chute adjoining the delivery end having a radius similar to the radius of the cone and providing a regular surface for sliding the material from the surface of the chute to the cone during rotation of the machine, the intake end of the spiral chute forming the leading end thereof during rotation of the machine in discharge direction, whereby the spiral chute elevates the material from the tumbling chamber to said cone, the sloping surface of the cone being effective to feed the material by gravity from the open delivery end laterally toward the discharge drum for advancement through the delivery drum.

6. In a tumbling machine having a tumbling chamber mounted for rotation about its longitudinal axis in charging and discharge directions and having a rearward end wall; means for discharging material from the tumbling chamber by a sliding action comprising, a discharge drum projecting outwardly from said rearward wall along said axis, said drum having a conical surface converging toward the outwardly projected end thereof, a spiral conveyor vane mounted in said drum, a spiral chute mounted externally upon said end wall, the end wall having an intake opening at the periphery of the tumbling chamber to receive the material in the chamber, a cone mounted externally upon the end wall coaxial to the discharge drum and having an end connected to the discharge drum, said cone tapering outwardly from the end wall toward the discharge drum, the said spiral chute having an open in take end communicating with the intake opening of the end wall and having an opcn'delivery end communicat-.

ing with said cone, the open delivery end of the chute spaced along the come from the end of the dischargedrum, whereby the cone provides an outwardly tapered surface leading from the open delivery end of the chute to the end of the discharge drum the portion of the chute adjoining the delivery end having a radius similar to the radius of the cone and providing a regular surface for sliding the material from the surface of the chute to the cone during rotation of the machine, the intake end of the spiral chute forming the leading end thereof during rotation of the machine in discharge direction, whereby the spiral chute elevates the material from the tumbling chamher to said cone, the surface of the cone being effective .to feed the material by gravity from the open delivery end laterally toward the discharge drum for advancement through the discharge drum by said spiral conveyor.

7. A tumbling machine adapted to operate in conjunction with an external separator which separates abrasive fragments and workpieces, the separator including .delivery means for advancing the-separatedabrasive fragments back to the tumbling machine; said tumbling mill com prising, a tumbling chamber mounted for rotation about its longitudinal axis and having a rearward end wall, a discharge drum mounted upon the said rearward end wallco'ncentric with said longitudinal axis and project ing outwardly, a collector chamber surrounding the discharge drum and having an end attached to the rearward the wall of the collector ring, said chutes having open outer ends adjacent the periphery of the ring, the chutes having inner ends communicating with openings in the wall of the ring thereby to deliver the abrasive fragments to the collector chamber during rotation of the machine, and means mounted upon the rearward end wall of the tumbling chamber for advancing the abrasive fragments from the collector chamber to the tumbling chamber during rotation of the machine.

8. A tumbling machine adapted to operate in conjunction with an external separator which separates abrasive fragments and workpieces, the separator including delivery means for advancing the separated abrasive fragments back to the tumbling machine; said tumbling mill comprising, a tumbling chamber mounted for rotation about its longitudinal axis and having a rearward end wall, a discharge drum mounted upon the said end wall concentric with said axis and projecting outwardly, a collector chamber surrounding the discharge drum and having an end attached to the rearward end wall, means for advancing abrasive fragments and workpieces from the tumbling chamber to the discharge drum, the outer end of the discharge drum discharging the materials upon said separator, a collector ring mounted upon the outer end of the collector chamber, said ring having a diameter substantailly larger than the collector chamber, the collector ring including a wall joined to the end of the collector chamber and having a lip spaced from said wall to confine the abrasive fragments delivered by the delivery means of the separator, conveyor means mounted upon the wall of the collector ring, the conveyor means having outer ends adjacent the periphery of the ring and having inner ends communicating with openings in the wall of the ring, thereby to deliver the abrasive fragments to the collector chamber during rotation of the machine.

9; A tumbling machine adapted to operate in conjunction with an external separator which separates abrasive fragments and workpieces, the separator including delivery means for advancing the separated abrasive fragments back to the tumbling machine; said tumbling mill comprising, a tumbling chamber mounted for rotation about its longitudinal axis and having a rearward end wall, a discharge drum mounted'upon the said end wall concentric with said axis and projecting outwardly, a collector chamber surrounding the discharge drum and having an end attached to the rearward end wall, means for advancing abrasive fragments and workpieces from the tumbling chamber to the discharge drum, the outer end of the discharge drum discharging the materials upon said separator, a collector ring mounted upon the outer end of the collectorcharnber, said ring having a diameter substantially larger than the collector chamber, the collector ring including a wall joined to the end of the collector chamber and having a lip spaced from said wall to confine the abrasive fragments delivered by the delivery means of theseparator, a series of radial abrasive return chutes mounted upon the wall of the collector ring, each of said chutes being generally square in cross section and havingspaced side walls, the outer ends of the side walls being spaced from the ring to provide intake openings, a baffle mounted intermediate the spaced side walls and having ,an outer end joined to the ring to deflect abrasive fragments into the chute, the chutes having inner ends communicating with openings in the wall of the ring to deliver the abrasive fragments to the collector chamber during rotation of the machine.

10. In combination with a tumbling machine having an open charging cone, a power operated loader for elevating and delivering material to the open end of the cone comprising, a vertical guide frame, a carriage mounted relative to the vertical frame, guide means on the carriage connecting the carriage to the frame, a hopper, said hopper including a pair of spaced side walls and a dis charge chute at one end, pivot means on the carriage, means on the hopper connected to the said pivot means, a hoist mounted upon the frame for elevating the carriage and hopper, the hoist having a cable extending therefrom, an equalizing member extending transversely across the top of the hopper, said cable connected to the equalizing member intermediate the length thereof, a pair of equalizing cables anchored to the opposite ends of the equalizing member and extending alongside the side walls of the hopper, the lower ends thereof being anchored to the lower portion of the hopper, respective arcuate cable guides mounted upon the said side walls at opposite sides and extending generally at a tangent to the axes of said equalizing cables and loosely confining the same, and stop means on the frame engageable with the carriage at an elevated position thereof to stop the carriage and to rotate the hopper about said pivot means upon continued upward motion of the hopper thereby to deliver the material into the cone. I

11. in combination with a tumbling machine having an open charging cone, a power loader for elevating and delivering material to the open end of the charging cone comprising, a vertical guide frame, a carriage, guide members on the carriage connecting the carriage to the guide frame for vertical movement of the carriage relative to the frame, a hopper having a discharge chute at its forward end, pivot means connecting the carriage and hopper, the pivot means located upon an axis extending transversely below the forward end of the hopper, a hoist mounted upon the guide frame for elevating the carriage and hopper, the hoist including a cable connected to the hopper at a plane located rearwardly of the said pivot means, stop means mounted on the frame and engageable with the carriage at an elevated position, a vertical guide flange mounted upon the frame at opposite sides, a guide pin mounted upon the hopper at opposite sides and residing at the lower portion of the guide flanges when the hopper is in lowered position, the pins traversing the vertical flanges during upward motion and maintaining the hopper in horizontal position as the same is elevated, the guide pins disposed above the upper ends of the flanges when the carriage engages the stop at its upper limit of travel, the hoist thereby tilting the hopper about the pivot means to discharge the material into the open cone.

12. In combination with a tumbling machine having an open charging cone, a power loader for elevating and delivering material to the open end of the charging cone comprising, a vertical frame disposed adjacent the open end of the cone, a carriage, guide members on the carriage connecting the carriage to the frame for vertical carriage movement, a material conveying hopper having a discharge chute at one end projected forwardly toward the end of said cone, pivot means connecting the hopper to the carriage, the pivot means extending transversely of the hopper below the discharge chute, a hoist on the guide frame for elevating the carriage and hopper, the hoist including a cable connected to the hopper at a plane located rearwardly of the said pivot means, and stop means on the frame engageable with the carriage at an elevated position thereof, continued elevation of the hopper by the hoist thereby tilting the rearward portion of the hopper upwardly, the pivot means located at a point to cause the end of the discharge chute to generate an arcuate path about the pivot means toward and through the plane of the open end of the cone to an angular position to discharge the material into the cone.

13. In combination with a tumbling machine having an open charging cone, a power loader for elevating and delivering material to the open end of the charging cone comprising, a vertical frame disposed adjacent the open end of the cone, a carriage, guide members on the carriage connecting the carriage to the frame for vertical carriage movement, a material conveying hopper having a discharge chute at one end projected forwardly toward the end of said cone, pivot means on the carriage, the hopper being pivotally connected to the pivot means, a hoist on the guide frame for elevating the carriage and hopper, the hoist including a cable connected to the hopper at a plane located rearwardly of the said pivot means, a vertical guide rail on the frame, a guide pin on the hopper slidably engaged relative to the rail for vertical movement with the hopper, the guide pin maintaining the hopper in horizontal position during its elevating motion and terminating at a plane below the upper limit of travel of the pin, stop means on the frame engageable with the carriage at an elevated position thereof, continued elevation of the hopper by the hoist thereby tilting the rearward portion of the hopper upwardly, the pivot means located at a point to cause the end of the discharge chute to generate an arcuate path about the pivot means toward and through the plane of the open end of the cone to an angular position to discharge the material into the cone, and a stop mounted on the frame in a position intercepting the arcuate path of motion of the guide pin, thereby to limit the tilting motion of the hopper.

References Cited in the file of this patent UNITED STATES PATENTS Gould May 22, 1951

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