US2238051A - Concrete placer - Google Patents

Description

gw E539 WMM, LQ. c. HACMLEY CONCRETE PLACER F11-C1 om. 4L, 1959 ATTORNEY.

Patented Apr. 15, 1941 `UNITED STATES PATENT FFME CONCRETE` PLACER Roy C. Hackley, Oakland, Calif. Application october 4, 1939, serial No. 297,836 s claims. (o1. a02-5s) This invention relates to concrete placers or guns and similar devices which employ a tank or container adapted to be substantially filled with concrete or similar material and in which the material is later discharged by the action of compressed air, and particularly to means for preventing stratication and partial setting of the material prior to discharge from` the container,

A placer of the type specified has numerous uses, among them being the placing of concrete lining in tunnels, subways, and like structures. Where tunnels are comparatively small in diameter, and where only one trackway can be provided, the concrete placer which supplies and places the tunnel liningI is usually loaded or lled with concrete at a point outside of the tunnel and is then run in on the track to the inner end of the tunnel where the lining is being placed. The distance from the outer to the inner end of the tunnel is often several miles. The placer or container is subjected to considerable pounding and vibration during transit over the trackway or rails which causes settling or stratification of the heavier aggregates in the concrete, and, as the transit period from tunnel opening to the place where the lining is being placed may consume from fifteen minutes to half an hour or more, there is a tendency for the concrete to become partially set. This stratication of aggregates and the partial setting which may take `place is very detrimental, as it forms a poor con# crete lining for the tunnel; i. e., portions of the tunnel lining will contain too large a proportion of heavy aggregates and as such may be porous and cause leakage, while other portions will consist mainly of fines, etc. Again, portions -of the inner surface will be found to `he rough and pitted, and may require both grouting and plastering to insure a uniform finish. Fnally it may be stated that dii'culty in discharging the concrete from the placer is also encountered due to partial setting and stratification of the aggregates, etc.

The object of the present invention is generally to improve and simplify the construction and operation of concrete placers of the character described, and more particularly, to provide means whereby the concrete may be maintained in a state of continuous agitation to prevent setting and stratication of the aggregates while the placer is in transit.

The invention is shown by way of illustration in the following drawing, in which- Fig. 1 is a central vertical longitudinal section of the concrete placer;

Fig. 2 is a detail view showing the cover for the filling opening;

Fig. 3 is a cross section taken on line III- III of Fig. 1;

Fig. 4 is `a cross section taken on line IV--IV of Fig. l;

Fig. 5 is an end view of the rear end of the placer showing the tank in discharge position; and

Fig. 6 is a similar View showing the tank in filling position.

Referring to the drawing in detail, and especially to Figs. 1 and 4, A indicates in general an elongated tank or container closed by heads 2 and 3 disposed at opposite ends. The tank is substantially egg-shaped in cross section, as shown in Fig. 4, and the bottom of the tank is formed into a series of steps such as indicated at 4, 5, E, 1, and 8, by interposing risers 33 between them. The head 2 on the front end of the tank is provided with a funnel-shaped discharge pipe 9, and on this is mounted a Valve IIl and a coupling I I. The arrangement of the steps 4 to 8 inclusive is such as to form a bottom which slopes from the head 3 to the discharge pipe 9. This general slope, together with the steps formed thereon, is of considerable importance as will hereinafter appear.

The tank is provided with one or more longi tudinally extending stay bolts II to reinforce the heads 2 and 3, but the entire interior of the tank is otherwise free and unobstructed with the exception that a few mixing vanes I2 are provided to assist mixing of the concrete when the tank is rotated, as will now appear.

. Inasmuch `as the tank must be run out to the mouth of the tunnel when it is to `be loaded or lled with concrete, particularly where the tunnel is of small diameter or width so that only one trackway can be employed, it is essential that the load transporting trip be made as quickly as possible, and even so, that the concrete be maintained in a state of agitation to prevent stratification and partial settling. To accomplish this, the tank is mounted on a bolster or frame Ill and this in turn on one or more trucks I5 and Iii. Such a portable mounting permits a quick return trip, but if the distance is a couple of miles or more, continuous agitation of the concrete within the tank is necessary. 'This is accomplished by welding or otherwise securing a pair of track rings IT exterior of the tank and at opposite ends thereof, and supporting the same in pairs of flanged rollers I8 mounted on the frame. This permits the tank to be rotated about its longitudinal axis, causing the concrete to be turned over and over and to be mixed by the vanes I2.

Where work of -this -character is dona-an electric locomotive is usually provided to haul the tank or placer in and out of the tunnel, and where this is the case, an electric motor 20 may be placed on the frame and supplied with current from the locomotive. The motor drives a reduction gear and this in turn, through a sprocket chain 2l and gears, forms a drive whereby the tank is slowly rotated during transit so that when the placer arrives at the point where the `concrete is to be discharged, settling of the aggregates and partial setting of t-he concrete is en-tirely avoided, and when it is discharged, a uniform mix is insured.

The discharge of the concrete is accomplished as follows: Extending rearwardly from each rise in the A-bottom of the tank are pipes, such `as indicated Iat da to 8a inclusive. These are all connected with a manifold 24, and this is in turn connected through a hose connection 25 with an air supply pipe which extends through the tunnel. A `coupling is provided on the hose whereby a quick connection with the manifold can be made. A similar coupling is provided on the end of the discharge pipe so that the moment the gun reaches the point where the concrete is to be discharged, it is quickly made ready to discharge its load. 'I'hus when the coupling connections have been made, the valves indicated at 26 are opened and air under a pressure of 80 to 100 pounds is admitted to the tank through the pipes 4o to 8a inclusive at the forward end of each step. The air thus admitted builds up the required pressure within the tank to discharge the concrete, and at the same time forces it forward into the discharge pipe; yand when the concrete has been all but discharged, .the inclined stepped bottom of the tank is swept clean by the blasts of air from the several pipes 4a to 8a, and the tank is completely discharged, as each nozzle -or pipe has a comparatively small area to clean, lto-wit, the step disposed in front thereof. This, together with the fact that all pipes, valves, etc., are mounted on the exterior of the tank, permits a free unobstructed interior surface and therefore a `complete discharge of the concrete.

In order that a placer of this character may be quickly lled with concrete when it is to be loaded, a filling opening 21 is provided and in addition thereto a cover 28 is also employed, as Vthe opening must be closed when air is applied to -discharge the concrete. Ordinarily the opening and cover are dis-posed on top of the tank, substantially midway of the ends. In this instance, the -opening and cover are disposed at one side of the tank, as clearly shown in Figs. 1 and 5. This is a decided advantage in the present instance as ythe head room of the apparatus as a Whole is considerably reduced, thereby permitting the placer to enter tunnels of comparatively small diameter. 'I'he placing of the filling opening in the side of the .tank would be impossible unless the tank were mounted for rotational movement, as the tank must assume the posi-tion shown in Fig. 6 with the lling opening uppermost when the tank is to -be lled, and it must assume the position shown in Fig. when the tank is to be discharged due to the arrangement of the stepped bottom and the position of the discharge pipe. In this instance, the -cover 28 is shown as yattached to a strong arm 29 pivoted as at 30 so the cover may be swung away from the filling opening during lling of the tank. Any other suitable arrangement may, however, be employed; for instance, that disclosed in my co-pending :application entitled Closure and actuating mechanism therefor, led April 14, 1937, Serial No. 136,771.

While the invention has been particularly described for use in connection with por-table placers or guns, it is equally applicable to stationary placers. For example, if, after filling and either prior to or in the course of discharge of the contents of the stationary placer delay in the discharge operation, occasioned by a variety of innumerable possible causes, takes place, it is now necessary at once to discharge and waste the remaining `concrete or material in the container in order to prevent setting thereof in the container during the period of delay. 'I'he expense and extra work entailed from such discharge is obvious and is entirely overcome by rotation of the stationary placer in the manner above described.

Having thus described and illustrated my invention, what I claim and desire to secure by Letters Patent is:

1. In a concrete placing apparatus of the character described an elongated horizontally disposed tank to receive concrete, a discharge pipe adjacent the bottom of the tank and at one end thereof, a plurality of steps formed in the bottom of the tank, with a riser at each step, said steps yand risers forming a gradual slope from one end of the tank toward the discharge outlet, and means disposed exterior of the tank and connected with each step for introducing air under pressure to move the concrete toward and into the discharge pipe.

2. In a concrete placing apparatus of the character described an elongated horizontally disposed tank to receive concrete, a discharge pipe adjacent the bottom of the tank and at one end thereof, a plurality of steps formed in the bottom of the tank, with a riser at each step, said steps and risers forming a gradual slope from one end of the tank toward the discharge outlet, and a plurality of `pipes disposed under the bottom of the tank and Iconnected with the respective risers, to introduce air under pressure to move the concrete toward and into the discharge pipe.

3. In a concrete placing apparatus of the character described an elongated horizontally disposed tank to receive concrete, a discharge pipe adjacent the bottom of the tank and at one end thereof, a plurality of steps formed in the bottom of .the tank, witha riser at each step, said steps and risers forming a gradual slope from one end of the tank toward the discharge outlet, means disposed exterior of the tank and connected with each step for introducing air under lpressure to move the concrete toward and into the discharge pipe, and means for rotating the tank prior to discharge of the `concrete to prevent setting and stratification of the aggregates v in the concrete,

ROY C. HACKLEY.

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