US2131732A

US2131732A - Tumbling mill

Info

Publication number: US2131732A
Application number: US194309A
Authority: US
Inventors: Charles H Hammell
Original assignee: American Foundry Equipment Co
Current assignee: American Foundry Equipment Co
Priority date: 1938-03-07
Filing date: 1938-03-07
Publication date: 1938-10-04
Anticipated expiration: 1955-10-04

Description

"Mb w Oct. 4, 1938. c. H. HAMMELL 2,131,732

TUMBLING MILL Filed March 7, 1953 3 Sheets-Sheet l lNvENToR ATTORNEY Oct. 4, 1938. c. H. HAMMELL 2,131,732

TUMBLING MILL @fr Filed March 7, 1953 3 Sheets-Sheet 2 INVENTOR BY Hummel! www ma ATTORNEY Oct. 4, 1938. c. H. HAMMELL 2,131,732

' TUMBLING MILL l Filed March 7, 1933 3 Sheets-Sheet 3"' Y ATTORNEY Patented Oct. 4, 1938 TUNIBLING MILL Charles H. Hammell, Mishawaka, Ind., assigner to The American Foundry Equipment Company, Mishawaka, Ind., a. corporation of Dela- Ware . 'Application March 7, weaseliai No. 194,309

16 Claims.

This invention relates to tumbling mills for cleaning and smoothing castings, forgings and the like. f

In cleaning, polishing, hardening or otherwise treating small metal articles such ascastings, forgings and the like, out in a tumbling mill in which the articles are placed and subjected to the action of projected abrasive particles while the articles are being tumbled.

When a single tumbling barrel is used it has been common practice to charge the articles to be treated into the barrel when the supply of projecting abrasive is shut off. After charging 'the barrel, the abrasive may be projected with suicient impact to clean the articles such as castings while they are being tumbled. After the articles have been treated the requisite length of time, the discharge of the treated castings requires shutting off the abrasive supply while the' tumbling barrel is being unloaded. It is, therefore, desirable to avoid these shut downs and maintain the abrasive throwing mechanism in operation continuously whereby to do active work without the necessity of relatively long shut downs incident to charging and discharging the tumbling barrel operating on the so-called batch system.

The present invention accomplishes the foregoing desirable end by providing a plurality of pockets or tumbling barrels mounted so as to be capable of being b-rought successively in and out of the path of abrasive' projected at blasting velocities. Provision is made to charge the barrels consecutively at a predetermined position while the barrels which have been charged are receiving abrasive cleaning treatment at another position or positions in the path of travel of the barrels. Simultaneously a barrel containing treated articles may be discharged at another position. Thus, the cleaning or blasting action may be continuous and the time incident to charging and discharging is not spent at the expense of shutting down the abrasive projecting mechamsm.

According to one form of the invention, the mill comprises a stationary casing in which is positioned a relatively large conveyor supporting wheel made up of two discs or frames in parallel spaced relation mounted to rotate on a horizontal axis. A continuous conveyor or belt is trained over sprockets mounted in the discs and over rotatable barrel heads also mounted on the discs. These are arranged to form, in effect, a plurality of tumbling barrels each having rotatable heads the process may be carried conveyor.

and a movable side wall provided by the conveyor. The tumbling barrels thus formed between the discs are positioned equidistant from each other and radially from the horizontal axis of the wheel formed by thevdiscs. Consequently, the 5 barrels may travel in a circular orbit when the large conveyor supportingwheel rotates on its axis.

Additionally, the conveyor belt may be caused to travel when the large wheel carrying it is l0 stopped for the purpose of tumbling articles in the barrels thus formed when they are in the cleaning position and to assist in discharging cleaned articles from the barrels when the barrels are in the discharging position in their orbit of 16 travel about the common horizontal axis of the large wheel.

The wheel assembly is arranged for step by step rotation, if desired, thus to stop the barrels intermittently at predetermined positions in their 20 y,orbit of travel. Mounted above the wheel are abrasive throwing devices positioned to project abrasive into one or more of the barrels to clean castings or other articles therein while they are being simultaneously tumbled by the travelling Provision is made to charge an empty barrel at another position or station in the orbit .while the cleaning operation just mentioned is proceeding. Further provision is made to discharge at the same time treated castings at another station.

Moreover, suitable means are provided for removing .the abrasive which has been projected into the mill and for returning it to the abrasive projecting mechanism whereby the abrasive can be used in a continuous cycle.

The invention also consists in certain new and original features of construction and combinations of parts hereinafter set forth and claimed.

Although the novel features which are believed to be characteristic of this invention will be particularly pointed out in the claims appended hereto, the invention itself, as to its objects and advantages, and the manner in which it may be carried out, may be better understood by referring to the following description taken in connection with the accompanying drawings forming a part thereof, in which:

Fig. 1 is a view partly in elevation and partly in section of one form of mill according to the invention; y

Fig. 2 is a View in cross-section on line 2-2 of Fig. l;

Fig. 3 is a view in cross-section on line Fig. 2; and

Fig. 4 is a view in part in elevation of one disc of the wheel assembly.

In the following description and in the claims, various-details will be identified by specific names for convenience, but they are intended to be as generic in their application as the art will permit. Like reference characters denote like parts in the several figures of the drawing Referring to the drawings, the conveyor supporting wheel assembly may be mounted on xed stationary hollow stub shafts I and II which may be supported in heavy pedestals I2 and I3 resting on a suitable foundation or heavy cross beams. 'Ihese hollow shafts are large enough to accommodate a screw conveyor I4. By connecting the inner ends of the stub shafts I0 and II which have a common axis with a pan I5 a trough is formed to catch abrasive which may be returned to a feed hopper I6 through suitableconduit and elevator means.

Two side wall members which may be in the form oi' discs I1 and I8 may be mounted in parallel spaced relation to rotate on suitable bearings which may be roller bearings I9 and 20 positioned at the inner endsrespectively of hollow shafts I0 and II. These side wall members may be connected by shafts 2| and rying spaced

sprockets

23 and 24 fixed thereto. The assembly forms a conveyor supporting wheel rotatable on a common axis of rotation through the centers of the shafts I0 and II. Each of the shafts 2| may be provided with a sprocket 29 mounted on the outer side of the side wall member I1. A chain drive 2 5 (indicated by dot and dash line) is trained over the sprockets 28 and may be driven by a motor 28. An idler 21 may be provided to keep the chain drive 25 taut.

v Between the side wall discs I1 and I8 there may be mounted a plurality of pockets or tumbling barrels each of which may comprise a pair of spaced barrel head members 30 and 3I rotatably mounted in `journals 32 and 33 in the wheel side walls I1 and I8 respectively. 'I'hus each pair of barrel heads rotate on a common axis. Eight of such pairs of barrel heads are shown although a greater or less number may be desirable in particular cases. It will be apparent from the drawings that the axes of rotation of the respective pairs of barrel heads are equidistant radially from the axis of rotation of the wheel assembly (designated generally by the reference character 28) and they are also equally spaced apart.

To form the side walls of the respective tumbling barrels of which the pairs of

barrel heads

30 and 3| constitute the end walls, a single continuous link belt 34 may be trained over the

sprockets

23 and 24, and the rotatable barrel heads 30 and 3I. Each barrel head may have an annular offset flange 35 on its periphery and each barrel head may have a liner plate 36 removably secured thereto, the liner plate '38 with the offset flange 35 forming a circular groove 31 to accommodate flanges on the link belt 34 to guide the link belt and to provide for rotation of the barrel heads when the conveyor belt is moved linearly; that is, in a direction over the

sprockets

23 and 24 and the barrel heads 38 and 3|.

Arcuate tracks

99 and 99 may be fixed on the side wall discs I1 and I8 to assist in guiding the conveyor belt 34 and to hold the slack.

Seal plates

39 and 40 may be provided on the periphery of the wheel as a partial protection to the

sprockets

23 and 24 and the conveyor belt chain drives 4I and 42.

22, each shaft car- Y mounted in the wheel assembly as shown generally in Fig. 2.

In order that the wheel assembly 28 may becaused to rotate intermittently or by a step by step movement about its axis of rotation a plurality of lugs 43 (see Fig. 4) may be mounted on the side wall disc I8 in a circular path. A spring pressed stop pin 44, mounted in the side wall 45 of the housing or casing 46, in which the wheel assembly is mounted, may coact with the lugs 43 to stop the movement of the wheel assembly. Thus, when the stop pin 44 is allowed to engage the side wall I8 of the wheel a. lug will engage the pin and prevent movement ,of

the wheel assembly. Hence, when the drive lrelatively heavy conveyor belt 34 will permit the drive chain 25 to rotate the wheel assembly on the shafts I0 and I I unless means are provided to stop its rotation.

If desired the stop pin 44 which is manually operated may be dispensed with and other means provided for the rotation step by step of the wheel assembly. An annular gear 41, which may be made of segments, may be fixed to the periphery of the side wall disc I 8. This gear may engage a pinion 48 fixed to a shaft 49 driven by a motor 58 connected with a suitable drive 5I. An electrical relay and timer (known in the art) foi` stop, pause and start operation may be connected with the motor 50 and suitable contacts corresponding to lugs 43.

Abrasive projecting mechanism such'as one or more centrifugal abrasive throwing wheels 52 and 53 may be mounted in the roof 54 of the housing or casing 48m such manner as to project abrasive at blast cleaning velocities into the casing and in the path of travel of the tumbling mills or pockets of the wheel assembly. It is preferable to project the abrasive in a downward direction into the tumbling barrels (as shown generally in Fig. 2) for cleaning articles which may be more conveniently tumbled when the curvilinear portions of the segments making up the side walls of the tumbling barrels form the necessary holding pockets. It will be apparent that articles such as castings and forgings in the uppermost barrels will be tumbled when the conveyor belt 34 is caused to move linearly, particularly when the wheel assembly 28 is not in rotating motion.

The stationary hollow shafts I0 and II support a suitable pan or trough I5 which catches the major portion of abrasive projected into the uppermost tumbling barrels since the link belt 84 provides ample slots or spaces to permit the used abrasive to fall through into the central trough be elevated to the feed hopper I6 through another conveyor 90 and again passed to the abrasive i mismas n I6. A screw conveyor I4 mounted to rotate In the hollow shafts I and II carry used abrasive into the elevator shaft 66 through which it may projecting mechanism.

In addition to the central abrasive trough I another abrasive collecting trough 51 may be provided in the lower portion o f the casing 46. This trough may likewise be provided with a screw conveyor 58 to carry abrasive, projected into the casing and not caught by the central trough I5, into the elevator shaft 56. The two screw conveyors I4 and 58 may be driven by a motor 59 suitably connected by drive chains 60 and 6I over

sprockets

62, 63 and 64.

Radially disposed baiiies 65 may be mounted between the side wall discs I1 and I8 to direct abrasive into the trough I5.

Additional baies

66 and 61 may be fixed to the casing walls to avoid undesirable splattering of the abrasive towardV the charging and discharging doors described hereafter.

The-casing 46 may be provided witha lift type charging door 68 positioned in the side wall 69 of the casing. A charging platform may be xed to the casing. It facilitates charging articles to be cleaned into the tumbling barrel opposite the charging door 68. l

A. discharge opening 1I having a discharge chute 'I2 may be provided in the opposite side Wall 13 of the casing. Itv will be apparent that articles in the tumbling barrel opposite this discharge opening will be carried out of the barrel into the chute when the conveyor belt 34 is caused tov move linearly in the direction of the arrow 'I4\.

Operation The tumbling mill may be operated as follows:

The wheel assembly may be adjusted to take the position shown generally in Fig. 2. The abrasiveconveyors I4, 58 and 90 together with the necessary elevator in shaft 56 are placed in operation. The tumbling barrel opposite charging door 68 is charged with a suitable quantity of articles, such as smallcastings |00. The conveyor belt 34 is placed in operation. The wheel assembly may then be caused to rotate a step in the.v direction of the arrow 29a so as to bring the charged barrel under the centrifugal abrasive throwing wheel 52 which is placed in operation. The next successive barrel is charged through the charging door while the articles |00 are being subjected to the projected abrasive. The wheel assembly is then caused to rotate another step thus to bring the first charged barrel under the abrasive throwing'wheel 53 which is placed in operation.

While the castings in the barrels beneath the throwing wheels are being tumbled by reason of the linear movement of the conveyor belt 34 and simultaneously subjected to the projected abrasive, the next successive barrelis being charged through the charging door 68.

After the articles are given the requisite cleaning by the abrasive projected by the throwing wheels, the conveyor supporting wheel assembly is caused to move another step, thus bringing a barrel containing cleaned castings opposite the discharge chute 'I2 and at the same time an empty barrel opposite the charging port 68.

It will be observed that the barrel opposite the discharge chute takes a position which is analogous to tipping the barreland the cleaned articles are carried out by the linearly travelling conveyor belt 34. While the cleaned castings are thus being discharged, uncleaned castings may be charged into a barrel oppositethey charging door 68', and simultaneously the castings in the barrels beneath the throwing'wheels are being cleaned. The operation may be carried on continuously step by step without the necessity of stopping the flow ofprojected abrasive which is returned and recycled through the throwing wheels.

Thus, a continuously operating tumbling mill at any time during the operation of the con-y tinuous mill.

While certain novel features of the invention `have been disclosed and are pointed'out in the annexed claims, it will be understood that var'ious omissions, substitutions and lchanges may be made by those skilled inthe art Without departing from the spirit of the invention.

What is claimed is: v

l. In apparatus of the character described, a conveyor `supporting wheel mounted to rotate about an axis, means mounted on said wheel to train a conveyor belt, a conveyor. belt trained by the aforesaid means to form a plurality of tumbling barrelsfdisposed about the axis of rotation of said wheel, means to move said conveyor belt along the path of travel provided by said training means, and means to rotate said wheel about its axis of rotation whereby to revolve said barrels in an orbit about saidv axis of rotation.

2. In apparatus of the character described, a conveyor. supporting wheel comprising spaced apart side frames mounted to rotate about a common axis, means including discs spaced apart mounted on said sidewalls to train a conveyor, a continuous conveyor trained by said means to 'form a plurality of tumbling barrels revoluble in about a common axis, means including discs` spaced apart in parallel relation and rotatable about another axis of rotation to train a conveyor, a continuous link conveyor trained in part by said rotatable discs to form a plurality of tumbling barrels revoluble about the axis of rotation of said wheel, means mounted on said wheel to move said conveyor linearly along the path of travel provided by said training means, and

means to rotate said wheel step by step to revolve said barrels intermittently in an orbit about the axis or"V rotation of said wheel.

4. In apparatus of the character described, a conveyor, means for training said conveyor to form.a plurality of tumbling pockets, projecting mechanism to discharge abrasive atblasting velocities, means for moving said pockets into and out of the path of abrasive discharged from said projecting mechanism, and means to move said conveyor to tumble articles within said pockets .when in the path of abrasive discharged at blastling velocity from said projecting mechanism.

5. In apparatus of the character described, a conveyor belt, means including rotatable barrel heads for training said conveyor to form a plurality of tumbling barrels, projecting mechanism to discharge abrasive at blasting velocities, means for moving said barrels in an orbit into and out of the path of abrasive discharged from said projecting mechanism, and means to move said conveyor belt to tumble articles within said barrels when in the path of abrasive discharged at blasting velocity from said projecting mechanism.

6. In apparatus of thecharacter described, a link belt movable linearly, means including rotatable barrel heads mounted on a. rotatable frame for training said conveyor to form a plurality of tumbling barrels on said rotatable frame, means for moving said barrels in an orbit about the axis of rotation of said frame, and means to move said belt linearly to tumble articles within said barrels when'in the path of abrasive discharged at blasting velocity on to said articles.

7. In apparatus of the character described, a conveyor, means for training said conveyor to form a plurality of tumbling pockets, projecting mechanism comprising a centrifugal blasting wheel to discharge abrasive at blasting velocities, means for moving said pockets into and out of the path of abrasive discharged from said blasting-wheel, means to move said conveyor to tumble articles within said pockets when in the path of abrasivedischarged at blasting velocity from said blasting wheel, and means to return used abrasive to said blasting wheel.

8. In a tumbling mill, aframe rotatable on an axis, a plurality of receptacles mounted on said frame revoluble in an arc about the axis of rotation of said frame, each of said receptacles including a belt movable in a curvilinear direction to tumble articles therein, mechanism for projecting abrasive at blasting velocity, means for moving said receptacles in said arc into and out of the path of abrasive projected at blasting velocity from said mechanism, and means to move said belt to tumble articles within a receptacle when it is in the path of projected abrasive.

9. Apparatus for blast cleaning metallic articles including, a frame rotatable on an axis, a

plurality of tumbling barrels mounted on said frame revoluble in an arc about the axis of rotation of said frame, each of said barrels including rotatable barrel heads and a b'elt movable in a curvilinear direction about the peripheryof said barrelheads to tumble articles'therein, mechanism for projecting abrasive at blasting velocity, means for moving said barrels in said arc into'and out of the path of abrasive projected 'at blasting velocity from said mechanism, and means to move said belt linearly when a receptacle is in the path oi projected abrasive.

10. A tumbling mill comprising, a casing, a frame within said casing rotatable on an axis, a plurality of tumbling barrels mounted'on said frame revoluble in an orbit about the axis'of rotation of said frame, each of said barrels including a pair of rotatable barrel heads and a movable belt trained over said barrel heads,y means for moving said barrels step by step in said orbit to bring each barrel successively into abrasive cleaning position, and means to move said belt linearly y relation and mounted to rotate on hollow shafts having a common axis of rotation, a plurality fof tumbling barrels mounted between said side wall members, said tumbling barrels being movable with said side wall members to revolve said barrels in an arc about the axis of rotation of said shafts, an abrasive moving member mounted within said hollow shafts to carry abrasive from said casing,and asecond abrasive moving member positioned in the lower portion of said casing to carry abrasive therefrom.

12. A tumbling mill comprising, a casing, a barrel supporting wheel within said casing having side wall discs spaced apart in parallel spaced relation and mounted to rotate on hollow shafts having a common axis of rotation, a plurality of tumbling barrels having rotatable end members mounted between said side wall discs, said tumbling barrels being movable with said side wall discs to revolve said barrels in an arc about the axis of rotation of said shafts, and a screw conveyor mounted within said hollow shafts to carry abrasive from said casing.

13. A tumbling mill comprising, a casing, a barrel supporting'wheel within said casing having side wall members spaced apart in parallel spaced relation and mounted to rotate on hollow shafts having a common axis of rotation, a plurality of tumbling barrels each having rotatable heads and' a curvilinear sidewall which constitutes a part of a continuous belt mounted vbetween said side wall members, said tumbling barrels being movable with said side wall members to revolve said barrels in an arc about the axis of rotation of said shafts,l a screw conveyor mounted within said hollow shafts to vcarry abrasive from said casing, and a second screw conveyor positioned in the lower portion of said casing to carry abrasive therefrom.

14. A tumbling mill which comprises, a casing, means to project abrasive at blasting velocity into said casing, two side wall discs in parallel spaced relation mounted to form a wheel within said casing rotatable on a common axis, a hollow shaft to carry said wheel, a plurality of pairs of barrel head members mounted between said side wall discs, each pair of barrel head members being rotatable on a common axis through their centers, a screw conveyor operable within said hollow shaft to. remove abrasive from said casing, rotatable shafts carrying sprockets connecting said side wall discs, a conveyor belt trained over said sprockets and rotatable barrel head members to form a plurality of tumbling barrels equally spaced apart and revoluble in an orbit about the axis of rotation of said wheel, means to rotate said sprockets .thereby to cause said conveyor belt to move linearly, and means in- .cluding a segment gear to rotate said wheel step by step about said hollow shaft to bring each barrel successively into the path of projected abrasive.

15. A tumbling mill which comprises, means to projectv abrasive at blasting velocity, two side wall discs in parallel spaced relation mounted to form a wheel rotatable on a common axis, a plurality of pairs of vbarrel head members mounted between said side wall discs, each pair of barrel head members being rotatable on a common axis through their centers, the axis of rotation of each pair of barrel head members being the same distance radiallyv from the axis of rotation of said wheel and equidistant from each other, anv

arcuate guide track mounted on said discs adjacent each of said barrel head members, ro-

tatabie shafts carrying sprockets connecting said side wall discs, a continuous conveyor belt trained over said sprockets and rotatable barrel head members and riding on said tracks thereby to form a plurality of tumbling barrels equally spaced apart and revoluble in an orbit about the 'axis oi! rotation of said wheel, means to rotate said sprockets thereby to cause said conveyor each pair of barrel head members being the same distance radially from the axis of rotation Aoi? rsaid wheel and equidistant from each other, an

arcuate guide track mounted on said discs adjacent each of said barrel head members, a screw conveyor operable within said hollow shafts to carry abrasive therefrom, rotatable shafts carrying sprockets connecting said side wall discs, a conveyor belt trained-over said ysprockets and rotatable barrel head members and riding on said tracks thereby to form a plurality of tumbling barrels equally spaced apart andvrevoluble in an orbitabout the axis of rotation of said wheel, means to rotate said sprockets therebyto cause said conveyor belt to move linearly, means to rotate said wheel step by step to bring each barrel successively into the path of projected abrasive, and a second screw conveyor for returning projectcd abrasive to said abrasive projecting means.

CHARLES H. HAMMELL.