US2315915A - Method and apparatus for handling concrete - Google Patents

Description

prl 6, 1943. C, wHlTE 2,315,915

METHOD AND APPARATUS FOR HANDLING CONCRETE Original Filed Nov. 2Q, 1959 Patented Apr. 6, 1943 UNITED STATES 'OFFICE 'METHOD APPARATUS FOR HNDLNG CONCRETE' cec-i1 J. White, Minneapolis, Minn.

r'iginal application Novenihe'r 20, 1939, vSerial No. 305,317. Divided and this application Deccmber A1, 1941, Serial No. 421,112

4 Ulaims.

My invention comprises a method and Aapparatus i or preventing the .segregation of the .larger particles of the concrete mixture yduring the Ideposit of the mixture upon a vsupporting medium vfrom a hopper or the like.

My invention also comprises .a method and apparatus for preventing the larger particles :of the Aaggregate of a paving mixture from lodging against the side forms 'or transverse joints in a slab `or other structure. The Iloidgm'ent of vsuch large particles of :the aggregate prevents the proper deposit .and entrance of :sufcient mortar at vsuch locations to il all `the voi-ds existing between the larger particles, and Amy invention guides the larger particles into the interior of the mass of material and permits the finer particles to lodge against the side forms or .transverse joints.

My invention also comprises a method land `apparatus for retaining amaterial, such asa sheet of joint material vused in roadways `and .other structures, in proper desired position during the -deposit of the concrete, and simultaneously preventing the larger particles l'of the concrete yor other mixture from Klodging 'against the form material, blocking oi the deposit .and entrance of suicient mortar at such location -to ll all v,oids between the large particles but guiding the large particles into the intermediate body of the mixture, permitting the ner particles of the `mixture to lodge against .the joint material.

My invention .also comprises a construction of the holder for such joint material in a manner that will hold the .joint material in proper position during the deposit of the concrete but also permitting the holding device to be easily removed after the concrete has been deposited. My `apparatus may also be used against the side `forms utilized in concrete roadway construction, .for .the practice of my method, in'preventing the .formation of voids and stony pockets at the 'sides and corners ofthe slabs or other structures.

The deposit of concrete upon a supporting medium such. for example, as the prepared subgrade of a highway, involves the problem vof preventing the formation of segregated 'pockets consisting of volumes of the coarser aggregate of the mixture in which the voids between the large particles are not completely filled with mortar. Ordinarily when concrete is discharged from the lower restricted throat of a hopper or concrete mixer bucket, there is a tendency for some of the larger aggregate to become segregated from the mixture and to .roll -down and lodge at the toe ofv the deposited mixture. Especially when the `hopper Iis the bucket of 'a paving 'mixJ this hopper .is :propelled longitudinally over the .subfgrade and at a predetermined elevation above the subgrade. The hopper is so manipulated that it tends to .distribute .the batch of concrete rather uniformly over Athe subgrade in an elongated, Liiatten'ed pile, .thereby reducing the labor of distributing .the fmixture between the 'side forms. I have found that when vconcrete is so deposited, the larger particles of the aggregate tend .to separate from. the mixture and to roll down the sides of the pile or mass and to accumulate Vatl the toes or edges of the pile inrows or ribs of segregated masses. After the .deposit of the rst .material is completed in this manner, :it is supplemented by manual distribution of thematerial laterally, with the result that .richer .portions of the concrete .are 'placed upon these segregated portions of the larger aggregate. The pavement slab is then ncompleted, leaving these rows or ribs o segregated Lmaterial in the 'lower strata of the concrete slab, and the voids in this segregated ma- .terial are then not completely lled with vthe mortar. This results in a pavement slab 'which .has .large void or honeycombed volumes of vcon- .siderable .length and width which weaken the slab `structurally and likewise permit 'the ingress of water which may later freeze, .disintegrating the slab.

I have `found thatby the use of my invention, the segregation of the larger aggregate from the .mixture is prevented, since the larger .aggregate `is retained within the body of the mixture dur- A.ing 'the deposit thereof upon the subgrade so that upon completion, the slab is of a Vuniform mixture throughout, free from voids and honeycombs and of uniform strength and density.

In fthe .construction of concrete roadway slabs upon a prepared 'subgrada the lateral edges of the lslab are shaped by what are commonly `called longitudinal side forms anchored to the subgrade .and defining the direction and height of the edges o'f the slab. At selected intervals .in the length of the slab, there are placed contraction and expansion joints, the latter in many cases consisting oi a vertical sheet or strip of a compressible and expansible mastic material extending from the subgrade upward almost to the upper finished surface :of the sieb. y'liheserjoints are ydisposed transversely to the axis 4of the roadway and extend from one side -form across the slab to the opposite side form. I 'have found that when concrete is deposited in the slab in the usual manner upon .the subgr'ade between the forms and yagainst the transverse joints, the

larger particles of the aggregate tend to become segregated from the mixture and to become deposited against the side forms and against the transverse joints, especially in the corners and at the lower edges of the slab. Although the concrete is later brought to desired finished surface elevation against the side forms and against the transverse joint, the mortar does not ilow readily into the voids of these segregated volumes, with the result that honeycombs and stony pockets, having a deficiency of mortar, exist at these critical locations when the slab has been completed.

This application is a division of my co-pending application, Serial No. 305,317, filed November 20, 1939, now Patent No. 2,274,225, patented February 24, 1942.

The apparatus employing my invention is shown in the accompanying drawing, in which:

Figure 1 is a perspective View of a bar carrying downwardly inclined ngers, which bar may be mounted on the inside of a hopper in such a way that the fingers guide the larger pieces of aggregate toward the interior of the mixture being discharged from the hopper;

Figure 2 is a vertical sectional view illustrating the hopper equipped with thel vfingers shown in Figure 1 and held above a supporting medium upon which the concrete is deposited;

Figure 3 is a vertical sectional View taken on the line 3 3 of Figure 2;

Figure 4 is a vertical sectional view of a specic apparatus embodying my invention;

Figure 5 is a top plan View of a portion of the apparatus of Figure 4; v

Figure 6 is a vertical cross sectional view taken on the line 6 5 of Figure 4, and

Figure 7 is a perspective view of another form of my apparatus. Y

In the drawing, Figure 1 shows a simplified device embodying the principle of my invention wherein a bar indicated by the numeral I supports a plurality of fingers 2 inclined outwardly from the bar. In Figures 2 and 3 I have shown a bucket or hopper 3 such, for example, as the bucket of paving mixers. Bars I are bolted or otherwise secured to the inner faces of walls 4 of the bucket 3 just above the lower edges of the walls surrounding the discharge orifice of the bucket. The fingers 2 in this embodiment extend inwardly and downwardly at the orifice. The fingers are so spaced that they permit the portion of the mixture consisting of the finer particles thereof to pass between them for discharge upon a subgrade 5. The original concrete mixture is indicated at 6 of Figure 2 and larger particles at 1. The spacing of the ngers 2 is such as to prevent the larger particles 'I from passing between the ngers 2. Consequently, during the Y flow'of the material 5 downwardly from the bucket 3, the larger particles I are guided toward the interior of the mass so that when the concrete 6 is deposited upon the subgrade 5, these larger particles 1 are retained within the body of the mass 6 and are not separated therefrom at a toe S of the deposited mixture. In Figure 3 I show the bucket 3 being propelled horizontally in the direction of the arrow 9.

In Figures 4, 5 and 6, I show a specific apparatus in which is incorporated a bar I having l the downwardly inclined iingers 2, the bar I0 performing essentially the same function as bar I of Figure 1. In Figures 4, and 6, the bar I0 is shown consisting of two parts II which together form an inverted U, having downwardly projecting legs to which are attached the ngers 2. At either end of the parts II, I attach sustaining members and handles I2. The parts II may be provided with hinges I3 by means of which the downwardly extending legs of the parts IIl may be opened or closed. I also provide a clamp I4 operating to hold together the parts II and I2 and spacer sleeve I4a between the parts I2, the

Y clamp I4 being arranged for removal from the members I2 so that the parts II may be opened or closed with respect to each other. I may elect to use only one-half of the bar II), consisting of one part II with its attached lingers 2. The handles I2 are provided with grooves or notches I5 to engage side forms I6. I also provide joint material I'I alongside of which, as a stiiener, I provide a vertical plate I8. I likewise provide a clamping channel I9 to hold the material II and the plate I8 in desired juxtaposition. It will be seen that the bar ID, consisting of the parts II (especially as shown in Figure 6), sustain and hold a clamping channel I9 and thereby sustain the joint material IT in the desired position. The fingers 2 may extend downwardly to make contact with the subgrade 5 to assist in bracing the joint material II against lateral defiection and distortion.

In Figure 6. I show the concrete 6 containing the large particles T and ner materials 2l). I also indicate a space 2l between the iingers 2 and the joint material I1, into which spaces 2I the liner materials 23 have been permitted to pass while the larger particles 'I have been restrained by the fingers 2 to a position within the body of the materials 6. In the manipulation of the apparatus shown in Figures 4, 5 and 6, the joint material I'I with its plate I8 and clamping channel I9 is placed in position upon the subgrade 5 extending between the side forms I5 and the parts I'I, I8 and I9 are held in rigid position by means of the downwardly extending parts II of bar I0,

which is sustained and xed upon the side forms I6 by means oi the notch I5. Concrete 6 is then deposited upon the subgrade 5 in the manner hereinbefore described, and when a surface 22 of the concrete 6 has been properly obtained, the clamp I4 is removed and then by means of the handles I2 the bar II) with its attached parts are extracted from the concrete 6, after which normal finishing and tooling operations are continued.

In Figure 7, I show a different form of my apparatus arranged to be used in conjunction with the side form I6. I provide a bar 23 having an inverted U-shaped cross section which is placed upon an upper rail 24 of the form I6, the bar 23 having downwardly projecting legs 25 attached to which are the downwardly inclined fingers 2. This bar 23 with its ngers 2 serves the same function with respect to the side forms I6 that bar I0 with its fingers 2 performs with respect to the joint material I'I of Figures 4, 5 and 6.

While I have used a paving mixer bucket for the purpose of illustrating the manner in which my invention may be used, as shown in Figures 1, 2 and 3, it will be understood that the invention may be employed in a great variety of other commercial equipment. Likewise, while in Figures 4, 5, 6 and 7 I have utilized the 'forms and joints normally utilized in the construction ol' concrete roadway slabs, it will be understood that my invention may be used in a great variety of other forms of construction. My invention may also be employed in conjunction with spouts, chutes or elephant trunks, for the deposit of concrete or other mixtures into forms or other positions Where the concrete is to be utilized.

Having thus described my invention, I now claim and desire to secure by Letters Patent of the United States:

1. In apparatus on the kind described for constructing concrete slabs including an upstanding sheet of joint material, a holder for said sheet including a member having a groove engaging the upper edge of the sheet, said member having downwardly inclined fingers located at predetermined distances from the joint material, said fingers being spaced apart from each other a distance less than the diameter of larger particles of the concrete, comprising guides for directing larger particles into the body of the concrete away from the joint material into the body of the concrete and permitting the finer particles of the concrete to lodge against the upstanding surfaces of the joint material.

2. In apparatus of the kind described for constructing concrete slabs including an upstanding sheet of joint material, a holder for said sheet including a member having a groove engaging the upper edge of the sheet, said member having downwardly inclined lingers located at predeter mined distances from the joint material, said iingers being spaced apart from each other a distance less than the diameters of larger particles of the concrete, comprising guides for directing larger particles into the body of the concrete away from the joint material into the body of the concrete and permitting the ner particles of the concrete to lodge against the upstanding surfaces of the joint material, and means for retaining the holder in Xed position during the deposit of the concrete.

3. In apparatus of the kind described for constructing concrete slabs including an upstanding sheet of joint material, a holder for said sheet including a member having a groove engaging the upper edge of the sheet, said member having downwardly inclined ngers located at predetermined distances frcm the joint material, said ngers being spaced apart from each other a distance less than the diameters of larger particles of the concrete, comprising guides for directing larger particles into the body of the concrete away from the joint material into the body of the concrete and permitting the finer particles of the concrete to lodge against the upstanding surfaces of the joint material, said holder comprising parts separable at the line of the groove, means for clamping the parts together, and means for releasing the parts from each other, thereby releasing the holder from the joint material.

4. In apparatus of the kind described for constructing concrete slabs including an upstanding sheet of joint material, a holder for said sheet including a member having a groove engaging the upper edge of the sheet, said member having downwardly inclined lingers located at predetermined distances from the joint material, said fingers being spaced apart from each other a distance less than the diameters of larger particles of the concrete, comprising guides for directing larger particles into the body of the concrete away from the joint material into the body of the concrete and permitting the finer particles of the concrete to lodge against the upstanding surfaces of the joint material, said holder comprising parts separable at the line of the groove, and means for removing the parts and their attached ngers from the concrete after the deposit of the concrete.

CEGID J. WHITE.

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