US2282467A - Rotary concrete mixer - Google Patents

Description

May 12, 1942.. J. P. FABER ROTARY CONCRETE MIXER 2 Sheets-Sheet l Filed Oct. l2, 1958 Y Nl.

I INVENTOR.

May 12, 1942- J. P. FABER ROTARY CONCRETE MIXER Filed Oct. 12, 1938. 2 Sheets-Sheet 2 INVENTOR'.l

' 7":ATTORNEY- Patented May 12, 1942 zJohn- P. Faber, Dunellen, N. J., assignor to Ransome Concrete Machinery Company, Plainfield, N. J., a corporation of TNew Jersey 'Application October 12, 1938, Serial No. 234530 3 Claims.

The improvements relate to rotary concrete mixers and primarily` to mixers of this character which have a rotary mixing drum divided into two compartments by a partition and communicating through anopening in said partition through which each batch of concrete aggregates after being partly mixed in one compartment is transferred to the other compartment where the mixing is completed.

In mixers of this type the aggregates, including water, are first charged into the initial mixing compartment and after a short mixing period therein are transferred to the second compartment from which they are discharged after being held therein for another Vshort mixing vperiod sucient to finish the mix, the charging, transferring and discharging operations being usually timed and synchronized for automatic operation, so that batches will be mixed simultaneously in both compartments, and the capacity of the mixer thus greatly increased. It has been found also that by mixing in this manner a ybetter mix may be obtained and better concrete produced.

A mixer of this character is described and shown in Patent No. 2,067,826' of January-12, 1937, to Bushnell and Faber, to which reference may be had for further details.

In the operation described the transferring means usually consists of a movable chute which in one position, known as the transferring position, receives the aggregates from' theH mixing blades or scoops as they rise to their uppermost position and causes them to gravitate through the opening in the partition and in' its other position deflects them back from said opening toward the lower part of the rst compartment where they are again picked up by the blades and dumped. An equivalent provision has been made, however, by having the blades or scoops so formed that they normally dump the aggregates in such a manner that they are directed through the opening, the opening being provided with a suitable doorwhich when 4closedl deflects the aggregates backinto the'rst compartment and when openedpermits them to pass through into the second compartment. Such means are described and shown in my application for Patent No. 49,022, filed November 9, 1935.

The present improvements relate more particularly to the rst form of transfer chute and the blades or scoops used in connection therewith which raise and dump the aggregates into or on the chute and are designedto provide devices which will cooperate more fully and effectively in the mixing and't'ransferring operations and which `will be strong, durable and dependable as well as more efficient. To this end I provide a rotating chute which in transfer position will receive the aggregates dumped therein by the rising blades and discharge them quickly and cleanly through the opening and into the second compartment andvwhen rotated to nontransferring or mixing position will deflect the said aggregates away from said opening and back into the lower part ofthe rst compartment, and I also provide blades so formed and constructed that they will raise the said aggregates, gather them in the zone lin which the chute is located and deposit them in or on the said chute at a pointand in a manner productive of the quickest and mostsatisfactory mixing and transferring. The employment of' a rotary discharge chute in concrete mixing .drums ,which will receive and discharge the aggregates in oneposition and when rotated to another position effectively close the discharge opening by diverting the materials therefrom is not new, such chutes having been in use for many years.

Chutes of this character have also been used in two compartment drums such asthat herein described and shown as transfer chutes for a number of years past. No claim therefor is made herein to such a chute either in combination with ordinary blades or blades designed to cooperate therewith in a general way,` the present improvements being limited to the particular construction, arrangement yand operationvof the transfer chute herein shownv and describedand in combination with the blades Vshown and hereinafter more particularly set forth. t

The improvements are illustrated in the -accompanying drawingain which t Fig. l1 is a vertical medial section taken Alongitudinally of a two-compartment rotary drum andaccessories embodying the improvements, the transfer'chute and certain other parts being shown in full lines; and y Fig. 2 is a transverse vertical section substantiallyon theline 2-2 of Fig. 1 looking in the direction indicated by the arrows in that figure. In thesaid drawings l represents the shell of the yrotary drum, which ismounted for rotation in the usual manner on annular tracks 2, propelled by an annular rack gear 3, has a charging head 4` with charging opening 5, discharging head 6 with discharging opening 'i and a central dividing partition 8 with transfer opening, 9 dividing the drum into compartments Il and I2, A fixed charging hopper I3 is locatedat the charging end and a swinging discharge' chute i4 vby full lines in the drawings.

at the discharge end. All these features of construction are old and in common use.

Mounted on the rock shaft l5, having an operating arm I6, a coupling l1 for its two sections and in turn mounted in roller bearings I8 in the spider I9 fixed to the inner shell of the drum is a transfer chute 20. This chute is mounted on a sleeve 2l xed to the shaft l5 in a saddle 22 with which it is united by welding or other suitable means, and is disposed substantially at an angle of 45 degrees to the shaft, its inner aring end extending slightly through the opening 9 in the partition and its outer contracted portion extending upwardly to a point between the longitudinal axis of the drum and the inner periphery thereof when in transferring position, as shown When however, the shaft l is rotated a quarter turn, by means of the crank arm I8, the chute is swung to a position in which its contracted end is substantially in the horizontal plane of the drum axis and its flared end is well above that plane. The result of this movement, therefore, is to shift the chute from a downwardly and inwardly inclined position in which it causes the aggregates to gravitate through the opening to a position in which aggregates discharged upon it by the blades from the upper part of the drum will be given a movement toward the charging end of the first compartment as well as laterally and toward the bottom of the drum. This second or non-discharging position of the chute is indicated by the dotted lines in the drawings.

The chute 2D is in the form of a trough, its sides being substantially concentric but unequal in length when viewed in discharging position, the side 23 extending farther above the horizontal than the side 24. When turned to nondischarging position, however, the side 24 is above side 23. The result of this arrangement is that in transferring position the `side 23 of the chute catches the aggregates dumped by the pockets 25 of the blades and prevents them from overshooting the chute, while in non-transferring position the side 24 is interposed between the aggregates falling from the pockets and the interior of the chute so that they are deflected thereby and gravitate back toward the bottom of the drum compartment and to a certain extent in the direction of the charging end. The backward inclination of the exterior upper part of the chute in this position also contributes to this movement of the materials.

The blades consist of the pockets 25, the adjacent wings 2S and 21 and the end wings 28 when rotated with the drum the blades are inclined when above mid height (see Fig. 2) toward the chute and to a point near the longitudinal medial portion of the chute. The pocket 25 is secured to the shell of the drum, and the extremities of the wings 21 and 28 are secured to the partition and charging head respectively, in the first compartment, but in the second compartment are secured to the discharge head and partition. respectively. The wings 2B and 21 join the pocket portions 25 and the wings 28 join the wings 26, the four elements being preferably a single blade bent and formed into these elements. The Wings are `spaced. slightly from the shell of the drum so be varied to a certain extent, so that the coarser aggregates will not pass the blades and only a part of the free liquid or soup can pass between them and the shell. As illustrated in the drawings, the pocket 25 is inclined toward the opening through which its load is to be discharged, and the wing 21 is inclined in the opposite direction. This provides for a pocket between them and also, in cooperation with the wings 26 and 28, gives the aggregates a direction of movement toward the said opening and approximately parallel with the chute, when both are in discharging or transferring position.

It will be noted from the foregoing, that the rotating chute and blades are designed to cooperate with one another in a peculiar manner. Thus the blades not only collect their loads so as to discharge them into the chute opposite its upper edge while moving them in the direction of the opening, but propel them constantly toward the opening so that the aggregates in the drum tend to form a pile with its apex toward the discharge end and so that the aggregates sliding off the chute when it is in non-transferring position will have a tendency to gravitate to the charging end; and that the chute will divert the aggregates falling on it from the blades not only backwardly but laterally in a divided stream spreading more widely toward the discharge opening and being diverted more abruptly, The aggregates which fall upon the descending blades are diverted toward the charging end thereby and the aggregates whichfall upon the ascending blades are diverted by the material thereon, as said blades are loaded to capacity from aggregates scooped up at the bottom. In this manner a peculiar movement of the aggregates is secured, and a d thorough mingling of them through the action of cross currents and cascading and turning over. When the chute is turned to transferring position the transfer is effected quickly and cleanly and the aggregates deposited within the zone 0f action of the blades in the second compartment. In this connection it will be noted that the chute extends into the second compartment a distance about equal to the spacing of the ends of the blade from the partition.

The chute 20 is provided with a flange 29 the periphery of which is annular and the central opening for the chute substantially parallel with said periphery. At its outer edge this ange has a flat ring 30 of rubber or other elastic material, while the partition around the edge of the opening has a metal ring 3| provided with a bead 32 extending over the space between the ring and the ring 30 of the chute ange, to protect this space against materials falling from the blade pockets and prevent them from passing therethrough. These rings are not in frictional contact, and if through vibration of the drum or slight movement out of vertical plane due to the operation of the parts they come in contact the ring will yield to a lsuilicient extent to prevent any impeding of the movement of the parts or damage thereto.

It will be seen that the drip and splash guard described in the foregoing paragraph is not a seal and does not act as a seal but acts as a guard composed of normally non-contacting parts. The ring 30 therefore, while it is preferably made of rubber or like elastic material, may, if such material is not available, be made of waterproofed leather, heavy canvas impregnated with a stiifening Waterproof substance or even of light steel, all of which have a certain degree of elasticity and sufficient for the purposes of the non-sealing ring. If desired the chute may be rotated more than degrees from transferring to non-transferring positions, but a rotation of 90 degrees has been found sufficient for the purposes designed. It will be observed that when rotated less than 180 degrees the smaller end of the chute is disposed laterally of the transverse horizontal axis of the drum and therefore has a tendency to divert the aggregates toward the side of the drum on which the blades descend so that they are not again brought immediately within the lifting influence of the blades. The crank arm I6, by which the chute is rotated may be operated by hand, but it is preferably operated by power and in timed relation with the charging, mixing and discharging means.

It will be noted that the chute 20 tapers in depth and width toward the charging head of the drum, that is to say its area decreases in that direction progressively. The chute however retains its trough-like form, so that in transfer position it will catch and convey aggregates discharged thereon by the blades throughout its length. This is the construction referred to in the appended claims as tapering and is to be distinguished from the flattening of the chute or an increase in its radius which would tend to permit aggregates to be spilled therefrom and become separated to some extent. The taper of the chute should correspond generally with the dumping capacity of the blades.

What I claim is:

1. The combination with a mixing and discharging device comprising a rotary drum having charging and discharging openings and means for charging thereinto materials to be mixed and discharging the mixed materials therefrom in batches and a partition in the interior thereof dividing said drum into a plurality of compartments said partition having an opening therein through which materials may be transferred from one compartment to another, of an'open transfer chute for transferring materials having one end located adjacent said opening and flaring from said opening toward said charging opening, means for rotating said chute to transferring and non-transferring position said chute being mounted in position inclined toward said transfer opening in transferring position and inclined away from said last named opening and the partition in non-transferring position, an annular flange on and extending from said chute substantially in plane parallel with the plane of said partition, an annular ring of flexible material extending from said flange into proximity to said partition and a ring on said partition extending over the said ring of flexible material and the interstice between it and the partition.

2. The combination with a mixing and discharging device comprising a rotary drum having charging and discharging openings and means for charging thereinto materials to be mixed and discharging the mixed materials therefrom in batches and a partition in the interior thereof dividing said drum into a pluralitykof-compartments said partition having an opening therein through which materials may be transferred from one compartment to another, of an open transfer chute for transferring materials having one end located adjacent said opening and flaring from said opening toward said charging opening, means for rotating said chute to transferring and non-transferring position said chute being mounted in position inclined toward said transfer opening in transferring position and having a portion inclined away from said last named opening and the partition in non-transferring position, an annular flange on and extending from said chute substantially in plane parallel with the plane of said partition, an annular ring of flexible material extending from said flange and into proximity to said partition and a ring on said partition extending over the said ring of exible material, said two last named rings being in close proximity.

3. The combination with a mixing and discharging devi-ce comprising a rotary drum having charging and discharging openings and means for charging thereinto materials to be mixed and discharging the mixed rmaterials therefrom in batches and a partition in the interior thereof dividing said drum into a plurality of compartments said partition having an opening therein through which materials may be transferred from one compartment to another, of an open transfer chute for transferring materials having one end adjacent said opening and extending from said opening toward said charging opening, means for rotating said chute to transferring and non-transferring position said chute being mounted in position inclined toward said transfer opening in transferring position and having a portion inclinedaway from said last named opening and the partition in nontransferring position, an annular flange on and extending from said chute substantially in plane parallel with the plane of said partition, an annular flexible ring extending from said flange and into proximity to said partition but normallyo ut of contact therewith and a ring on said partition extending over the said flexible ring, said two last named rings being in close proximityI y JOHN P. FABER.

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