US1998749A - High discharge concrete mixer and method of operating the same - Google Patents

Description

April 23, 1935. c. F. BALL HIGH DISCHARGE CONCRETE MIXER AND METHOD OF OPERATING THE SAME Filed May 16, 1931 2 Sheets-Sheet 1 Clea/6117,80

C. F. BALL April 23, 1935.

HIGH DISCHARGE CONCRETE MIXER AND METHOD OF OPERATING THE SAME Filed May 16, 1931 Q2 Sheets-Sheet 2 Patented Apr. 23 i935 r I I UNITED STATES PATENT OFFICE HIGH DISCHARGE CONCRETE MIXER AND METHOD OF OPERATING THE Charles F. Ball, Milwaukee, Wis, assignor to Chain Belt Company, Milwaukee, Wis, a cornotation of Wisconsin Application May 16, 1931, Serial No. 537,926

10 Claims. (Cl. 83- 33) This invention relates to concrete mixing or Often soft end of unknown dri agitating apparatus, and has for one of its obcapacity; Because of these factors, viz., the reljects the provision of a concrete mixer or agietiVeiy h transit speeds, and e act o tator of the truck or transit type so constructed the terrain e Which the truck y e d to .5 and arranged that the portion of the mixture- Operate in order to reach delivery positio it is 5 carrying receptacle which is provided with .the of material importance that the center of gravity discharge opening may be elevated at the time f the ad b pt as l w, r as close t h of, discharge materially ab it normal mixing truck chassis, as the nature, of its structure will and transportation position, such elevation being P d b us f t is r qu me of W 10 accomplished without excessively raising the cencenter Of i y, t discharge Opening of the 10 ter of gravity of the machine; there being means r eptacle, which is ge e a y at b o the provided for carrying on the agitation of th medial horizontal plane thereof, has of necessity concrete while at the same time positively movbeen held SOJOW as t0 Seriously handicap ing it to and through the discharge opening dur livery of concrete in truck mixers or agitators in ing such elevation, with the result that thebenemany instances. l5 fits of a discharge point materially above the That is to say, in the Placement of nermal p ion of the discharge opening during crete from truck or transit mixers, it is frequently mixing and transportation are attained, while at desirable at the concrete be flowed directly the same time minimizing to a'practically negligiinto forms which are higher than the normal disble point the dangers of instability arising from Charge P t Of the truck mixer, into a 1115- 20 excessive raising of the center of gravity, and tilibiltihg trough 0 Chute through Which t ay which have characterized all previously proposed flow by gravity t a Point considerably removed high discharge truck concrete mixers and agitafrom the mixer. It has been heretofore proposed tors of which'I am aware. to accomplish this result in connection with agi- In order that the precisenature of the invenin bodies of t e nonrotatine type th ou h 25 tion may be better understood, it may be said the bodily elevation of the entire receptacle, acthat truck mixers and agitators, as developed in Companied y a rearward downward l ti this country, are usually provided with an elonof the receptacle so that the concrete material ated mixing or agitatingireceptacle permanently might flow by gravity through t Usual real mounted ona motor vehicle chassis, with its londischarge p n This bodily elevation and 30 gitudinal axis in alignment with the lo gitudi r rearward downward inclination of the entire reaxis of said chassis. The. receptacle is ordinarily cepta le also rai es nd m v r w rdlv h provided with a port or opening in th rear d center of gravity ofthe mixer and the concrete wall through which the mixed concrete is disere There is always more or less dan e in .35 charged, and which opening is generally closed shifting the center of gravity ina truck-supported by a gate or cover during the mixing and transload of concrete, esp a y When standing on portation of the concrete. These receptacles are around of uneven or unstable character. In-

, now built in sizes to carry up to five or six cubic stances are own of truck mixers O this typ yards of concrete, which may weigh as much as be ng v ur d, su t ng in great damage to ten or twelve tons. property, and also extreme danger to the lives 40 In order that concrete may be. economically of those employed about the construction work. transported in tr uck mixers or agitators between Truck mixers or agi ators 'Of this p are Ordi- Ihepoint of loading and the place of discharge, y P ed With revolving blades D d it is important that the apparatus be capable of ed Within a re a y stationary y and attainingcomparatively high transit speeds. As driven through Suitable c nne ti ns m th 45 the points of loading and discharge maybe sevtruck motor. 'In all previous apparatus of this eral miles apart, itis common for truck mixers type with which I am familiar, however, it has to operate at road speeds of thirty 'miles per been necessary to break the power drive of these hour, or more, where such'speeds are permitted. agitating paddles whenever the receptacle is eleby law, carrying say ten or twelve tons of convated for discharge purposes, with the result that 5,

crete between such points. Again, this transduring such discharge it has not been possible to l ported concrete is in many instances for use in revolve the agitating paddles, and considerable construction operations, and it frequently hapdifllculty has been experienced inthe absence of pens that at the point of delivery the machine such agitation, in getting the concrete to flow 65 must traverse rough, ungraded, hilly or sloping through the discharge opening. As a matter of fact, in actual practice it has nearly always been necessary in this type of machine for the operator to climb into the receptacle and move a large portion of the concrete toward and through the discharge-opening by hand.

As before stated, only non-rotating'agitators have been elevated in the manner described, and it is to be noted that the extreme raising of the center of gravity would be even more dangerous in the case of mixers or agitators of the rotating drum type, such for example as shown in my prior Patent No. 1,781,965, dated November 18, 1930, wherein the torque incidental to the starting of the drum in the discharge direction of rotation, the said drum containing perhaps 4 cubic yards of mixed concrete or more, may be so great, under certain conditions of ground on which the truck is standing, as to be quite apt to result in the overturning of the vehicle, should the entire unit be elevated in the manner above described.

A high discharge point is advantageous in so many instances that it is extremely desirable to provide a structure, adaptable primarily to truck mixers of the rotating drum type exemplified by my prior Patent No. 1,781,965 above mentioned, but also susceptible of use in the non-rotating receptacle type, which will permit of the attainment of such high discharge point in safety, through the maintenance of a relatively low center of gravity of the mixer and batch of concrete contained therein, during discharge as well as during transit.

Hydraulic cement concrete mixtures, because of their inherent tendency to begin to set or harden soon after the hydration of the cement.

is completed, should preferably be kept in a state of agitation to retard such action until they are in the forms or other final place of use. Also, in the case of the wet or soupy mixes, i. e., those having a relatively high ratio of water to dry constituents, there is a well recognized tendency for the large aggregate to segregate and settle to the bottom unless agitation is continuous. In the case of these wet mixes in particular, it is highly desirable that agitation continue during discharge, to insure completely uniform concrete.

Agitation of the mixture, not only during transit, but also during discharge, is therefore an additional factor to be considered in connection with high discharge.

To provide a truck mixer capable of high discharge and embodying the above considerations, I mount the mixing or agitating unit upon the truck chassis in such manner that the receptacle may occupy a lowered substantially horizontal mixing and transpor ation position, in which mixing or agitation may e th most effectively car-' ried on, and in which the center of gravity is at its lowest feasible point, considered in the light of the limitations imposed by present dayautomotive vehicle construction, the mounting being such however, that at the time of discharge the receptacle may be inclined upwardly toward the discharge end to raise the discharge opening substantially above its said lowered position. When in such inclined position, the-center of gravity is raised only slightly, or to a materially lesser extent than is the discharge opening, and due to the shifting or sliding of the plastic mixture to the non-discharge end, such center of gravity is also moved somewhat forwardly of the truck, so that for all practical purposes, the machine is as stable in its discharge position as in its mixing and transportation position. Means are also associated with the receptacle for agitating the will appear as the description proceeds the invention consists in the novel details of construction and combinations of parts constitutingv the apparatus, and the novel steps and combinations of steps constituting the method of operation, all as will be more fully disclosed below and particularly pointed out in the appended claims,

Referring to the accompanying drawings forming a part of this specification in which like reference characters designate like parts in all the views:--

Figure 1 is a side elevational view, of a transit mixer of the rotating drum type constructed in accordance with the present invention to obtain the desirable high discharge, the parts being shown in the discharging position; and

Figure 24s a similar side elevational View partly in section of a slightly modified form of the con struction.

Referring more particularly to the said drawings the motor truck or vehicle In is provided with a chassis frame ll upon which the mixing or agitating unit I2 is mounted. The said unit, as disclosed in my said prior patent, comprises longitudinal sills l3, which carry the rotatable drum or receptacle M which may' be driven by means of the independent motor I 5 also mounted on the said sills. In the prior construction these sills l3 have rested upon the longitudinal chassis members l6 and have been rigidly bolted thereto so that the rotative axis of the mixing or agitating receptacle 14 has been substantially horizontal. It has thus beenimpossible to elevate the discharge opening .l'! and hopper I8 of the receptacle except through the building of ramps up which the rear end of the Vehicle might be run.

In order to obviate'the necessity of such ramps and at the same time to secure the advantages of the high discharge, in the, present instance there are provided brackets 20 carried by the truck chassis ll immediately adjacent the cab, and companion brackets 2| carried by the forward ends of the sills 13 of the agitating unit, which brackets are pivotally connected as at 22, all as is clearly illustrated in Figure 1. Mounted upon the truck chassis is any suitable elevating apparatus here shown as comprising a fluid pressure cylinder 23 from which projects a pistonor operatingrod 24 carrying a roller 25 which bears against the cam surface 26 of the bracket member 21 carried by the sills l3 of the agitating or mixing unit., The bracket member 21 as will be clear from the drawings is arranged adjacent the'rear end of the unit and the parts are so constructed and arranged that as'the rod 24 is projected from the cylinder 23 and the rear end of the unit l2 will be elevated from its usual horizontal position to the position shown in Figure 1, through the action of the roller 25 upon the inclined surface 26, all as is well known in the art of vehicle body elevation. The details of the elevating mechanism constitute no particular part of the present invention as obviously any suitable form of such mechanism may be employed and that shown has been selected for illustrative purposes only. I

When the elevating mechanism is operated as above described the mixing or agitating'unit I2 will betilted about the pivotal connection 22 so that the rotative axis of the receptacle M is inclined upwardly and the rear or discharge end of the receptacle is raised or elevated above the forward or non-discharging end, consequently raising the discharge opening i? and the hopper it. The said hopper may be elevated as much as two or two and a half feet above its normal position when the unit 52 is in its lowered or horizontal position, and the concrete from the drum may thus be discharged through the opening H from this additional elevation. Such discharge may be accomplished in the case of the rotating drum through the action of the spiral mixing blades (iii which are provided upon the inner periphery of the drum and the discharging buckets iii arranged adjacent the discharge opening ll.

As fully disclosed in my prior patent above men tioned, and copending application filed June 24, 1931, Serial No. 546,591 these blades and buckets are so constructed and arranged that during rotation of the drum in one direction they serve to not only lift and agitate the concrete mixture, but also to move it endwise toward the forward end of the drum, while upon rotation of the drum in the opposite direction they continue the agitation and at the same time move the mixture toward the discharge end and toward and through the discharge opening ll. It is thus possible in apparatus of this rotating drum type to positively discharge the concrete material from the receptaele through the discharge opening ll even though the said receptacle be inclined in such direction that the tendency of the material is to flow toward the forward end. Furthermore, since the drum M is driven through the independent motor i which is carried upon the sills it the drum drive is not interrupted or anywi'se affected through the inelination of the unit and the drum may be rotated for discharging purposes when inclined as shown, just as efiectively as it could be when in its normal horizontal position.

The form of the invention illustrated in Figure 2 is. quite similar to that shown in Figure 1 with the exception that the pivotal connection 22 has been moved somewhat toward the rear of the unit [2 although it still remains forward of the center of gravity of the unit. With this construction,

' although a slight decrease in the extent of elevation results, the angle of inclination remains substantially the same, and the compensating advantage of retaining the center of gravity at nearly its normal position is had; and, as above pointed out, due to the torque resulting from the starting of the drum containing perhaps four cubic yards of plastic concrete, it is of extreme importance to maintain the center of gravity of the entire machine as low as possible in order to pre- .vent upsetting of the mixer. The modified form of Figure 2 also has the advantage that a lighter hoisting mechanism may be employed, with a resulting saving in cost, and in some instances, a manual hoist may be used.-

In as much as the mixing and agitating blades 30 and the pick-up and discharge buckets 3| are operative at all times it isobvious that discharge of the drum contents may be effected not only when the drum is inclined as shown in the drawings, and when it is in its normal horizontal mixing or agitating position indicated in broken lines in Figure 1, as in my said prior patent and application but also in any position intermediate the two, thereby providing an effective discharge at any point within the limits of movement of the discharge opening.

It is obvious that those skilled in the art may vary the details of construction as well as the precise arrangement of parts without departing from the spirit of the invention, and therefore it is not wished to be limited to the above disclosure except as may be required by the claims.

What is claimed is:

1. In concrete mixing and agitating apparatus,

a support; a receptacle having a discharge opening, mounted onsaid support in a normally substantially horizontal position; means for inclining said receptacle to raise its discharge end above its non-discharge end while maintaining the center of gravity at nearly its normal position; and agitating means operative while said receptacle is thus inclined, for agitating the concrete within said receptacle and moving it toward and through said discharge opening. v

2. In concrete mixing and agitating apparatus, a support; an agitating receptacle having a discharge opening at one end, tiltably mounted upon said support; means for tilting said receptacle to elevate said discharge opening above its normal position while raising the center of gravity a lesser amount; and means within said receptacle for simultaneously agitating and moving the concrete therein through said discharge opening while it is elevated.

3. In concrete mixing and agitating apparatus, a support; a rotatable mixing or agitating recep tacle tiltably mounted upon said support, said receptacle being provided at one end with a discharge opening; means for inclining said receptacle to elevate said discharge opening above the non-discharge end of the receptacle while raising the center of gravity to a materially lesser extent; agitating means carried by said receptacle for simultaneously agitating and compelling movement of the concrete therein through said discharge opening while in its elevated position; and means for rotating said receptacle upon its axis while in both its normal and its inclined positions.

4. In concrete mixing and agitating apparatus, a support; a rotatable mixing or agitating receptacle having a discharge opening at one end, tiltably mounted upon said support; means for raising the discharge end of said receptacle above the non-discharge end to elevate said discharge opening above its normal position without materially raising the center of gravity; mixing blades and discharging buckets within said receptacle, adapted when said receptacle is rotated in one direction, to agitate and compel movement of the concrete therein toward and through said discharge opening when said receptacle is in either its normal or its inclined position; and means for rotating said receptacle upon its axis when in either of said positions.

5. In concrete mixing and agitating apparatus, a support; a mixing or agitating unit including a rotatable receptacle having a discharge opening at one end, mounted upon said support with the rotative axis of said receptacle normally substantially horizontal; a pivotal connection between said unit and said support adjacent the non-discharge end of said receptacle; means for swinging said unit about said pivotal connection 'to raise its discharge end above its non-discharge end and to elevate said discharge opening above its normal position without materially raising the center of gravity of the machine; means mounted on the inner wall of said receptacle which through rotation of the latter in one direction simultaneously agitate and impel the concrete therein toward and through said discharge opening when the latter is elevated; and means for rotating said receptacle while in its inclined position. i

6. In a transit concrete mixer or agitator, a vehicle chassis; a mixing or agitating unit pivotally connected adjacent its'forward end to said chassis, said unit including a rotatable drum having a discharge opening at its rearward end, the rotative axis of said drum being normally substantially horizontal; means for moving said unit about said pivotal connection to incline said rotative axis and elevate the discharge end of said drum bove its non-discharging end while raising its cen er of gravity to a materially lesser extent; means including spirally arranged blades on the inner surface of said drum for simultaneously agitating and moving the drum-contents toward and through said discharge opening when said drum is inclined; and means for rotating said drum when inclined. I

I. In a truck mixer or agitator for concrete and the like, a vehicle chassis;'a mixing or agitating unit pivotally connected forwardly of its medial portion to said chassis, said unit including a receptacle having a discharge opening at its rearward end, and said receptacle occupying a substantially horizontal position during transportation; a hoist for moving said unit about its pivotal connection for discharge to elevate the discharge end without materially raising the nondischarge end or the center of gravity of the unit; agitating means within said receptacle; and means for moving said agitating means while the receptacle is inclined to agitate and impel the mixture toward and through the elevated discharge opening.

8. In a truck mixer or agitator for concrete and the like, a supporting frame; a mixing or agitating receptacle closed at one end and having a discharge opening at its other end, pivotally connected to said frame, whereby it may occupy a lowered mixing and discharging position in which its center of gravity is at substantially its lowest feasible point, and may be tilted to an inclined discharging position in which the discharge end is elevated above the non-discharge end and said discharge opening is raised materially above said lowered position, while said center of gravity is raised a materially lesser extent; means for inclining and lowering said receptacle; and means operative when said receptacle is in either its lowered or its inclined position for agitating its contents and moving them toward said discharge opening.

9. In a truck mixer or agitator for concrete and the like, a vehicle chassis; a rotatable mixing or agitating receptacle having an axial discharge opening in one end and closed at its other end, said receptacle being pivotally mounted on said chassis and adapted to normally occupy a substantially horizontal mixing position in which its center of gravity is at approximately its lowest feasible point; means for tilting said receptacle about its pivot to elevate its discharge end above its non-discharge end and raise said discharge opening materially above its lower position, while raising the center of gravity to a considerably lesser extent; means within said receptacle and operable in either position of the receptacle through rotation thereof in one direction to agitate its contents for mixing, and through rotation in the opposite direction to continue the agitation while moving said contents toward and through said discharge opening, said means being operative to discharge said contents when said receptacle is in either its lowered or its tilted position, or in any position intermediate thereto; and means for rotating said receptacle.

10. A truck mixer or agitator for transporting, agitating and delivering concrete or the like having a truck chassis adapted for rapid road travel; a receptacle of large transverse dimension relative to the chassis wheel-width and having a discharge opening at one end, carried on the rear portion of the chassis frame with its longitudinal axis in the plane of the chassis axis, said re ceptacle normally occupying a lowered position in which the most effective mixing may be had and in which the inherent lateral stability of the vehicle is at its maximum; rotatable means in said receptacle for agitating the concrete and also moving it to discharge position; connections between the truck and receptacle whereby the latter may be moved to-an inclined position in which its discharge opening is elevated materially above its-

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