US2135874A - Discharge for concrete mixers - Google Patents

Description

Nov. 8, 1938. E. H. LICHTENBERG E-r AL 2,135,874

DISCHARGE FOR CONCRETE MIXER Filed May 1, 1935 Patented Nov. 8, 1938 UNITED STATES was? FFlCE DISCHARGE FOR CONCRETE ivnxsns Application May 1, 1935, Serial No. 19,282

3 Claims.

This invention embodies certain improvements in concrete mixing machines of the type utilizing a rotating drum for the agitation of the aggregate materials, and a discharge chute dis- 5 posed operatively at the discharge opening of the drum and movable to positions wherein it prevents or effects the discharging action from the said agitating receptacle. To those versed in the art of these mixing machines it is known that the discharging operation of a machine of this general type referred to involves an elevating of the material from the lower portion of the drum to the upper portion by certain socalled pick-up buckets, which, in association with certain throw-over blades, produce the necessary agitation to mix the various aggregates handled in the machine. The discharge chutes heretofore employed have been designed so as to be mounted at the discharge opening of the drum,

and the chute is movable from what may be termed its non-discharging position, to a discharging position wherein one end of the chute is disposed near the upper interior portion of the drum in such a position that the aggregates being agitated and elevated are caused to be deposited in the upper end of the chute and to flow downwardly from the chute to a point external to the drum.

In previous discharge chute mechanisms, such as above described, the natural line of flow of the concrete aggregates as they are raised and pass from the pick-up buckets is curved in the direction of the rotation of the drum. That is to say, as the aggregates are elevated by the pick-up buckets at a certain point in the elevation, they flow from the pick-up buckets by gravity and inertia imparted thereto incident to the rotation of the drum, along a curved flow line. A certain portion of the aggregates under these conditions will pass into the upper portion of the chute when the latter is in its discharging position, and will thus pass out of the drum. However, on account of the disposition of the inclined discharge chute, when in discharging position, at an abrupt angle to the direction of flow of the aggregates passing thereto from the pickup buckets, the action of the chute, according to arrangements prior to this invention, has been 50 to somewhat abruptly interrupt the direction of flow of the aggregates to carry them in the direction of the inclination of the chute, giving rise to certain disadvantages. In the 'first place, this interruption of the direction of the flow in 55 an abrupt manner has a certain tendency to segregate the aggregates when they are impinged against the wall of the chute as they take the outward flow in a new direction for discharging from the receptacle. Again, a Very considerable abrasive action of the aggregates incident to such impingement is produced against the chute wall or'walls, thereby creating wear which in time necessitates the replacement of the chute.

In the carrying out of this invention, the particular object in View has been to provide a 10 mounting for the discharge chute such that it is given an inclination, when in discharging position, which inclination corresponds with the inclination, so to speak, of the curved line of flow of the aggregate materials as they pass from the 15 pick-up buckets onto the chute in the discharging operation.

It has been found, by the coordination of the direction of inclination of the chute in its discharge position with the natural curved flow line 20 of the aggregates passing from the pick-up buckets thereonto, that the disadvantages previously referred to are avoided, and, in addition to this result, it has been found that an increase in the speed of discharge owing to the elimination of momentary stoppage of the movement of the aggregates necessary when they change their angle of flow on entering the discharge chute, is produced. 30

In the accompanying drawing the present invention is shown according to one embodiment thereof adapted to the construction of a mixing machine wherein the discharge chute is of the type which is pivotally mounted adjacent to the discharge opening of the mixing drum so as to be shifted from a position wherein the body of the chute is arranged almost entirely external to the drum for nondischarging action, and is shifted pivotally so as to carry practically the entire 40 body of the chute into the drum to a position for receiving the aggregates from the pick-up buckets when the discharging action is desired. However, it is not desired to be limited to this particular type of discharge chute mechanism, for 45 the principles of the invention may be adapted to other discharge chute constructions, within the purview thereof.

In the accompanying drawing Figure 1 is a side elevation of a mixing machine embodying a construction of discharge means made according to the invention.

Figure 2 is an end View looking toward the discharge end of the machine and illustrating the peculiar angularity of the mounting of the discharge chute itself, the same being illustrated as when operative for discharging purposes.

Figure 3 is a fragmentary perspective view looking toward the discharge end of the 'machine, and showing the discharge chute as disposed in a non-discharging position.

Figure 4 is a fragmentary, somewhat diagrammatic view, partly broken away and partly shown in section, of the drum, illustrating the movable and stationary discharge chute devices as when the movable chute is performing its discharging function by receiving the mixing aggregates from the pick-up buckets carried by the interior walls of the drum.

Referring to the drawing and describing the invention in detail, it is notable that the mixing machine illustrated comprises certain conventional parts including a frame I, the charging hopper 2, the drum 3, the movable discharge chute 4, and the stationary discharge chute 5. The drum is supported by suitable rollers and is driven by drive pinions 6 carried by a suitable motor driven shaft 1, the said pinions engaging one .or more annular gears or gear rings surrounding the drum. The drive pinions and gears are not shown in detail in the drawing, but the motor for actuation of the shaft 1 is-denoted 8. A water tank 9 supplies water to the drum in the customary way through a suitable water pipe Ill.

Referring now to the discharge mechanism, involving particularly the chutes 4 and 5, it is noted that the chute 5 is stationary and mounted between certain uprights of the frame I in any suitable and substantial manner. The upper end of the stationary chute 5 terminates adjacent to the discharge opening of the drum which is located at the side thereof opposite to that at which the charging hopper 2 is mounted. The movable discharge chute 4 is disposed above the discharge chute 5 and in practical use may constitute a continuation of the chute 5 when the chute 4 is disposed in discharging position. The chute 4 is directly carried by brackets ll secured to and movable with an actuating shaft l2 which is supported in suitable bearing brackets carried by the parts of the frame I at the discharge end of the machine. One of these parts of the frame is an inclined brace or supporting member Ia, seen best in Figure 2, said member Ia supporting the upper end of the said inclined actuating shaft l2.

By oscillation of the shaft l2 the discharge chute 4 carried thereby may be shifted from a position such as shown in Figure 3, wherein it is inoperative and practically withdrawn from the drum 3, to the position illustrated by the inner dotted lines of Figure 1, wherein the said discharge chute has its lower or outer end just above the inner or upper end of the chute 5, and its upper end projecting inwardly into the drum and upwardly to a point somewhat but not greatly spaced from the path of movement in which the pick-up buckets 13 of the drum operate. In the inward operative position of the chute 4, wherein it performs its discharge function, the upper end of the chute receives the mixed aggregates elevated by the pick-up buckets l3, and said aggregates flow down the chute 4 onto the chute 5 and thus out of the drum to any suitable receptacle or point of deposit.

The means with which to actuate the shaft 12 are not essential or material to the invention. This shaft could be shifted to assume its two positions described, in small machines, by a manual handle carried by the shaft -or connected therewith. But in larger machines,'such as illustrated in the drawing, it is contemplated to operate the shaft I 2 by means of a curved rocker arm H attached to one end thereof and connected by an actuating link I5 to certain power discharge mechanism, including a shaft l6 having a crank I! directly attached to the lower end of the link l5. This power discharge mechanism may involve alternative manual control means, but, since these manual and power operated devices are not essential features of the invention, they are not further described. Such mechanisms are common in the mixing machine art today and will be fully understood'without detailed showing and description by persons acquainted with such machines.

The important feature of the invention lies in the disposing of the chute 4 in the manner seen in Figure 2, namely, so that when the chute is in its discharging position, it inclines not only toward the charging end of the drum, but is disposed at .an inclination to a vertical line intersecting the axis of the drum when viewed from the discharging end of the machine. The last mentioned inclination is one corresponding in direction with the curved line of flow of the aggregates mixed in the drum as these aggregates pass from the pick-up buckets when the latter reach their uppermost positions at which the aggregates must shift from the said buckets incident to the gravitative action of the aggregates and the inertia imparted thereto by the rotation of the drum. It will, therefore, be seen that the longitudinal axis of the chute 4 is angularly disposed with respect to the horizontal and vertical planes of the longitudinal axis of the mixing drum 3.

Figure 4 of the drawing illustrates in a somewhat diagrammatic manner the manner in which the inclination of the chute 4 corresponds with the more or less inclined path of movement of the aggregates as they pass from the pick-up buckets to the chute, this path being a curved flow line, practically speaking, of which curved flow line the line of inclination of the chute 4 is intended to be a continuation.

Since the aggregates in passing from the buckets l3 to the chute 4 are not required to be abruptly stopped and shifted with a direction of flow at an abrupt angle to the natural flow line thereof when leaving the pick-up buckets, the speed with which the aggregates may pass onto and along the chute 4, and out of the machine, is increased as compared with the prior types of discharge devices. Likewise, as previously suggested, the impact of the aggregates against the chute 4 is substantially in line with the longitudinal axis of the chute and thereby a material reduction in the abrasive action of these aggregates upon the chute is obtained. The speed of discharge of the aggregates is highly desirable in these machines because the factor of the time of discharge is one of the several controlling factors that determines the efliclency of the entire mixing machine in its operation. The speedier the discharge, therefore, the more mixing operations may be performed in a given time of daily or other use of the mixing machine. Again, the avoidance of the requirement of replacing the discharge chute because of the abrasive wear caused by the aggregates thereon atfords a saving of expense and avoids loss of time in making the replacement, giving rise to essential advantages in the use of the discharge mechanism of the invention.

Having thus described our invention, what we claim as new and desire to secure by Letters Patent of the United States, is-

l. A mixing machine of the character described, comprising, in combination, a mixing drum, parts within said drum for agitating and elevating aggregate materials within said drum, a discharge chute movable to discharging and non-discharging positions extending into said drum, and means for pivotally mounting said chute with respect to said drum, including an axis member angularly disposed with respect to the horizontal plane of the longitudinal axis of the drum, whereby upon movement of said chute to discharging position aggregate materials within the drum elevated by said parts are transferred to said chute and discharged from the drum substantially in their direction of flow from said parts.

2. A mixing machine of the character described, comprising, in combination, a mixing drum, parts within said drum for agitating and elevating aggregate materials within said drum, a discharge chute movable to discharging and non-discharging position extending into said drum, means for pivotally mounting said chute with respect to said drum including an axis member angularly disposed with respect to the horizontal plane of the longitudinal axis of the drum, and instrumentalities for pivotally moving said chute about said axis member to discharging or non-discharging positions, whereby upon movement of said chute to discharging position aggregate materials within the drum elevated by said parts are transferred to said chute and discharged from the drum substantially in their direction of flow from said parts.

3. An apparatus of the character described, comprising, in combination, a mixing drum, means within said drum for agitating and elevating aggregate materials within the same, a discharge chute associated with the drum and movable to discharging and non-discharging positions, and instrumentalities for movably mounting said chute with respect to said drum and including a shaft and bearing members for said shaft, the shaft and bearing members being disposed with their longitudinal axes at an angle with respect to the horizontal plane of the longitudinal axis of the drum, whereby upon movement of the chute to discharging position aggregate materials within the drum elevated by said means are transferred to said chute and discharged from the drum substantially in the direction of flow from said agitating and elevating means.

ERICH H. LICH'IENBERG. OSCAR SHECK.

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