US1523548A - Mixer-batch control means - Google Patents

Description

Jui, 20, 1925. 1,523,548 E. H. LICHTENBERG l MIXER BATCH CONTROL MEANS Filed July 5, 1922 A iITLmunmlum iE. E. Effi' my @traineau Patented llan. 20, 1925.. 1

ERICH H. LCHTENBERG, OIE' ML'WAUKEE, WSCONSIN. ASSGNOR TO KOEHR'ING ClVlANY, GF MILXVAUKEE, WSCONSN, A CORPORATION.

MIXER-BATCH CONTROL MEANS.

Application filed July 5, 1922. Serial No. 572,907.

To all whom it may concern: quantity of aggregates, is introduced later Be it known that 1, Euicir H. Lioii'rnN- than when the fixed mixing period begins; 55

enne, a citizen of the United States, residing and that the mixing period should be timed at Milwaukee, in the county of .Milwaukee from the moment when all of the various agand State of Visccnsin, have invented cergregates including the water have been tain new and useful Improvements in Mixerbrought together in the mixing receptacle to Batch Control Means, of which the followsubserve the desired objects of obtaining a ing is a specification. vhighly efficient, uniform concrete, and an It has been customary in methods and man etiiciently operating machine. rEhe time i0 chines for concrete mixing purposes, to make when what I call the predetermined mixing concrete by collecting the aggregates includperiod begins may be characterized as the ing usually coarse aggregate, sand, cement, zero hour of the mixing period. For the and water, in a mixing receptacle, agitating water to be started into the mixing receptatlie same therein a definite predetermined cle before the zero hour, and before all of i5 period, usually a minute, and then dischargthe other aggregates have been assembled in ing the concrete fi'oiii the receptacle for use. the receptacle, is not harmful, but for the r[he mixing period has been satisfactorily converse method or operation to be employed predetermined or fixed by using a batchis likely to result in, or will result in a prodinetensuch as is shown by my Patent Number uct of less efficiency. By efficiency of a 20 1,321,460, issued November 11, 1919, the patconcrete product, l mean that factor that ent of Yletmore No. 1,338,761, issued May 11, renders the concrete long lived.

1920, and the patent of Ferguson and lVig, Obviously in order that the highest efli- No. 1,282,558 issued October 22, 1918. The ciency of a concrete mixing machine may be batchmeter while controlling the mixing obtained, producing the highest grade efperiod factor involved in the production of licicnt concrete, it is necessary that there an eliieient concrete, has not heretofore in be as many mixing periods of a controlled any 'way controlled the factor of the insuitable length, as is possible to obtain in a tegrity of the ultimate product as the same given hour of time. To accomplish this all is determined by or depends upon the water of the aggregates including the water should 30 content. Engineers of concrete construction be in place in the agitator or mixer at the have for a long time had before them the zero hour of the mixing period, the mixprobleiii of regulating within reasonable ing should then immediately commence and limits, Erst, the amount of water contents of the discharging of the material should take concrete aggregates iii relation to the other place promptly upon the completion of the aggregates, and second, the time of the in period, and no sooner. 1t will, therefore, be corporation vitli or addition of the water to, seen that it is necessary in some way to interthe other aggregates. The quantity or lock the operations of controlling the time of amount of the water ecets' seriously the mixing with the time of discharging, atleast virtue of the tinal product or concrete, and to the extent of preventing the discharge i0 the saine is true as regards the time when sooner than the expiratioi'i of the predethe water is added to the other aggregates termined mixing period, and to also interin the mixing operation. riihe last inenlock the control of the mixing period with tioned factor has to do also with the efthe admission of the rater to the mixing reiiciency of the mixing instrumentality or niaceptacle together with the admission of the 45 chine, for reasons hereinafter presented. other aggregates to said receptacle. rflic Experiment proves that the consistency of foregoing is accomlilished in the carrying a batch of fifteen hundred pounds of aggi'e out of my present invention. 100

gates, for instance, is substantially changed lVhile the customary methods of supplyby the adding or subtracting of four pounds ing and introducing water to the mixing re- 50 of water, that the final products are of difceptacle require a considerable period of ferent efficiency ratios when a portion of the time, 1 improve thereon in this invention by proper predetermined quantity of water, deutilizing a special forcing means in the way sirable to be combined with a predetermined of a pump operable by the skip to introduce said water into the mixing receptacle in a minimum amount of time, and this feature of my invention alone, is believed novel, as well as its use in conjunction with the other interlocked controlling instrumentalities more fully set forth hereinafter.

In its general mechanical features my invention deals with the problems which I have set forth above, by utilizing a batchmeter adapted to indicate the expiration of the predetermined mixing period, to lock the disc iarge of the mixer against discharging action until the end of the mixing period, set in action by the skip which loads the coarser aggregates into the mixer, together with a water supply means which is operated positively by the skip to forcibly introduce the water into the mixer in a minimum amount of time, the relations of the parts being suoli that not until all of the aggregates including the water are in the mixer is the batchmeter operated to control the commencementof the mixing period. Preferably, I allow the water to be started into the mixer before the other aggregates are completely in said mixer, because as a general thing the introduction of the water is a slower process than that of merely chuting the coarser aggregates into the drum of the mixer by the loading skip.

There is a condition met with in practice which I have undertaken to accommodate for in the development of my inv-ention, namely, the situation that under some conditions today the operator of a concrete mixing machine i's at times called upon to add a slight quantity of water to the aggregates if the same happen to be unusually dry, and the predetermined quantity is insuilicient to produce the desired quality of concrete. In the preferred form of my invention the operator has no control whatever over the amount of water forming a part of the aggregates, but if the practice of permitting the operator to add a very slight quantity of water is continued, in a modification of my invention I make a. provision for this contingency. The provision made involves a manual control of the water supply to permit an extra quantity of the water to pass into the mixing drum, but if this is done, thru intermediate mechanical devices the batchmeter is re-set, so to speak, so as to reinstate the mixing period with the time of commencement thereof running from the time when the last amount of water is put into the mixer. Under these conditions it must be seen that it is impossible for the mixing period predetermined as necessary for the machine to make good concrete to start earlier than the ti'me when all of the aggregates including the water are in the mixing drum. This is a highly important control feature.

In the accompanying drawing:

Figure 1 is a side view showing nearly the entire construction of what is known as a concrete paver of paving machine, of a type universally used today for laying concrete pavements, and well known to those versed in the art.

Figure 2 is a side view somewhat enlarged and showing in section certain parts, of the water tank and the controlling valve and pipes of the water supply and mixer water supply features of the machine.

Figure 3 is a side view partly in section showing a modified construction wherein the water supply is adapted to be manually operated and will reset the batchmeter to the commencement of its control operation under such conditions.

Figure 4; is an end view of certain parts shown in Fig. 3.

Figure 5 is a detail view showing more clearly the engagement of the abutment rod and its operating arm.

Figure 6 is a sectional view of the water control valve and union in which it is mounted.

Figure 7 is a perspective view of the friction clamp.

The paver comprises a mixer 1, boom and bucket mechanism at 2 and 3, a loading skip l, hoisting means for the skip including a cable 5, and suitable supporting frame work 6, with traction mechanism 7. The mixer or mixing drum l is equipped with a discharge chute 8, adapted to be turned into a discharging position by a handle 9 on a shaft 10, (see Fig. 3). Above the mixer 1 is a water tank 11 with which is connected a water supply pipe l2 leading from a source of water supply of any suitable nature, the water entering the tank 1l under pressure depending' upon the particular conditions. The skip 4 may be any kind of a loading or charging means, of course.

The tank construction is best seen in Fig. 2, wherein the tank 11 is shown as open at one end and having a piston or plunger 13 operating therein against the pressure or head of water supplied from the pipe 12 which connects with the tank 11 at one extremity as seen at 12a. The pistou 13 is equipped with a piston rod 14. extending thru a guiding spider 15 on the end of the tank and made hollow or tubular at its outer end as shown at 16. In this hollow outer end is a spring 17 engage-d by the yieldable abutment rod 18 which operated within the hollow portion 16 of the rod 14, and has an opening at 1S2L thru which a pivoted arm 19 extends. The movement of the piston or plunger 13 within the tank l1 may be varied or adjust-ed by shifting an adjustable stop 2O connected with the rod let by a fastening Q1 that may be passed thru different openings in said rod 14. By this expedient the piston 13 may be permitted to move different distances toward the right hand or open end of the tank 11 under the pressure of water which enters the tank from the pipe 12. For this reason obviously different quantities of water may be received by the tank and later supplied therefrom to the mixing receptacle or mixer 1. The arm 19 is connected by a rod 22 with the valve lever 23, a friction clamp 24 see in Fig. 7 engaging the rod 22, and being pivotally connected at 24a with the valve lever 23. The valve lever 23 controls the. three-way valve 25 seen best in Fig. (5, which valve in one position permits passage of the wat-er fi'om the supply pipe 12 to the tank 11, and in the other position cuts ofi' the water from the supply pipe 12 and connects the tank 11 with the pipe 2G which leads downwardly and into the mixing` drum. The valve 25 is located in a union disposed so as to connect the tank end 12b of the pipe 12 with the body of said pipe and at the same place connect the pipe 26 with the pipe 12 and portion 12b aforesaid.

At 27, (see Fig. 1) is a batchmeter which may be of any known type at present in use and comprising an alarm 28 to sound the time of completion of a predetermined period, and a lock 29 leading down to a locking disk 30 on the shaft 10 of the handle 9 of the discharge chute S. The rod 22 leads to the batchmeter 27 so as to set the latter into action at a proper time now to be set forth in detail in the description of the operation of my machine as thus far disclosed.

As the loading skip 4 is raised with a batch of the dry or coarse aggregates, usually gravel, sand, and cement, to load the batch into the mixer 1, an abutment 31 on the skip engages the abutment rod 13 on the piston rod 14 at a certain stage in the upward movement of the skip, the abutment iod is thus forced inwards or toward the water tank, comprising the spring 17 and imparting a slight initial movement to the rod 22 through the arm 19. This initial movement opens the valve 25 to establish communication between the tank 11 and the pipe 26 which leads to the mixing drum. At the same time the communication between the tank 11 and the pipe 12 is cut off. This adjustment allows the water to pass from the tank 11 to the mixing drum and the valve is moved just before the skip 4 starts to move the rod 14 after the rod 18 is moved to the limit of compression of the spring 17. The valve 25 having established communication between the tank 11 and the mixing drum, the skip 4 begins to move the rod 14 and the piston or plunger 13. The plunger 13 now forcibly pushes the liquid contents of the tank 11 therefrom thru the pipe 26 into the mixing drum, and when the plunger 13 reaches the limit of its expelling movement the tank 11 is empty and the mixer is supplied with the whole quantity of water required for its ordinary mixing operation. Before this time, in practice, the contents of the skip 4 will have already entered the mixer, so that at the end of the plunger movement 13 as aforesaid, all of the aggregates including water are in the mixer. The additional movement of the rod 22 beyond that caused by the initial operation of the same by the abutment rod 18 is allowed owing to the sliding of the rod 22 thru the friction clamp 24.

As the skip 4 starts to go down the pressure on the abutment rod 1S by the bracket 31 is relieved and said rod 1S under the force exerted by the previously compressed spring 17 is pushed outwards to its .normal position shownin Fig. 2, so far as its relation to the rod 14 is concerned. This return movement of the abutment rod 1S gives a preliminary actuation or impulse movement to the rod 22 in the rightward direction as seen in Fig. 2, thereby shifting the valve lever 23 to restore the valve 25 to its position as shown in Fig. 6. The eon'imunication between the Water tank 11 and the mixing drum 1 is thus promptly cut off as the skip 4 starts to lower, and the communication between the supply pipe 12 and the tank 11 simultaneously restored. Thereupon water again enters the tank 11 under the pressure or head in the supply pipe 12 and pushes the piston 13, takes rod 14 and rod 18 downwardly to the normal position shown in Fig. 2, the rod 22 being pulled thru the friction clamp 24 thru which it is free to slide though the frictional connection is sufficient that movement may be imparted from the part 22 to the part 23 when the latter is disposed in a position in which it may move under the actuation of the rod 22. The lever 23 of course is limited in its movement .in opposite directions by any suitable stop means shown at 23"L as lugs near the pivoted end of the lever. When the batchmeter 27 is started into action by the return movement of the rod as just set forth, the discharge chute 8 is locked by the lock-bolt or rod 29, and after the redeter mined period of mixing, usually one minute had elapsed. the batchnieter sounds its alarm bell 2S and lifts its locking-bolt 29 so as to release the discharge chute and permit it to be turned for the discharge of the contents of the mixer 1. Y

If desired, I may use instead of the locking-bolt 29, the construction of discharge chute operating means disclosed in Letters Patent of Robb No. 1,370,497 issued March 1, 1921, by which the discharge chute is moved to its discharging position automatically on completion of the proper period of mixinv'. In Figures 3 and 4 is illustrated my method of using a manual valve lever 23X which is connected with the batchmeter 27, the starting shaft of which is designated 'lli Sul

lll)

lit)

32. The provisions now to be set forth are to enable the operator to add a little quantity of Water to that already in the mixer when the conditions so require. If the ad dition is made, however, the batchmeter 2T is re-set to its starting position so that the mixing period is recommenced, so to speak, in so far as the control by the batchmeter is concerned any time any additional Water is put into the mixer. This necessitates that under any condition of use of the mixing machine the mixing period as controlled by the batchmeter must start after all of the aggregates, including the Water, have entered the mixing drum. This is the prereq uisite hereinbefore stated as necessary for the purposes of an invention of this character.

By my invention just set forth as regards Figures 3 and 4f, should the operator upon completion of the mixing of a batch of concrete, after releasing of the shaft l0 from the bolt 29, turn over the chute 8 and notice as the concrete comes from the chute that it does not contain enough Water, he may throw back the chute and by manual operation of the lever 23, add a little Water by a full opening of the valve and permit closing at Will. IVhen he does this he re-locks the discharge chute at its shaft 10 and disc and resets the batchmeter, and a complete second mixing period is compelled so that there is no possibility that incomplete mixing may be performed. As shown in Figure 3, the movement of the handle of the valve lever 23, to open the valve and supply more Water to the mixer l, operates a rod 33 having the full stroke compelling member 34 on its left hand end Within the batchmeter 27. This member 34 is adapted to engage a latch member 35 having a cam 36 co--operating with a plate 37 Which depresses and holds in locking position the latch bolt 29 until the same is released by the mechanism of the batchmeter in the Well known Way.

If desired, a diaphragm controlled pressure cut off 38 may be used in conjunction with the tank 11 to automatically cut olf the flow of water from the pressure supply means to the tank, when the pressure reaches a predetermined amount.

`With the foregoing' in view it will be evident that under all conditions of use of my invention there is no liability of the mixing of the aggregates, including the Water, a less period than that fully controlled by the batclnneter, which may be in accordance of course with a required specification. Like- Wise of course the means employed by me is especially advantageous, in that the measured quantitv of Water in the tank 11 may be expeditiously forced therefrom and introduced into the mixer l by positive pressure and under the automatic action of the skip 4L.

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

1. In a concrete mixing machine, in combination, a mixer, a loading device for charging non-liquid aggregates thereinto, a Water supply leading to the mixer, and means controlled by the loading device for forcing the predetermined amount of Water necessary for a particular batch of concrete, from said supply into the mixer before the Zero hour of the mixing period begins.

2. In a concrete mixing machine, the combination of a mixer, a Water supply tank having communication therewith, a loading device for charging aggregates into the mixer, and means intermediate the loading device and the tank for positively forcing Water of a predetermined quantity from the tank into the mixer as the loading device charges the coarse aggregates into the mixer.

3. In a concrete mixing machine, the combination of a mixer, a Water tank having a piston therein, a loading skip for charging aggregates into the mixer, and means intermediate the skip and the piston for forcing the latter to move in the tank and thus force a predetermined quantity of water into the mixer, on charging movement of the skip.

4. In a concrete mixing machine, the combination of a mixer, a Water tank having a piston therein, a loading skip for charging aggregates into the mixer, means intermediate the skip and the piston for forcing the latter to move in the tank and thus force a predetermined quantity of Water into the mixer, on charging movement of the skip, and a Water supply connected With the tank to supply Water thereto under pressure by which the piston in the tank may be restored to its normal position after it has been operated by the skip.

5. In a concrete mixing machine, the combination of a mixer, a water tank having a piston therein, an instrumentality controlling charging of aggregates into the mixer, means intermediate the instrumentality and the piston for forcing the latter to move in the tank and thus force a predetermined quantity of Water into the mixer, on |charging action of the instrumentality, a valve controlled communication bet-Ween the tank and the mixer, and means operable automatically preliminary to the operation of the piston by the said instrumentality to open said valve to permit Water to flow from the tank to the mixer when the piston is actuated by the skip.

6. In a concrete mixing machine, the combination of a mixer, a Water tank having a piston therein, a loading` skip for charging aggregates into the mixer, means intermediate the skip and the piston for forcing the latter to move in the tank and thus force a predetermined quantity of Water into the mixer, on charging movement of the skip, a valve controlled 'communication between the tank and the mixer, and means operable automatically preliminary to the operation of the piston by the skip to open said valve to permit water to flow from the tank to the mixer when the piston is actuated by the skip, and operable automatically after the water has been forced by the piston into the mixer to cut olf the communication between the tank and the mixer, and a water supply means communicating with the tank and controlled by the valve aforesaid so as to have communication with the tank when the said valve cuts olf communication between the tank and the mixer.

7. In a concrete mixing machine, the combination of a mixer, a loading skip for charging aggregates into the mixer', a water tank to supply water to the mixer to combine with the coarser aggregates supplied by the loading means, a water supply connected with the tank, a water supply means leading from the tank to the mixer, and a valve automatically operable by the loading skip both to alternately open the communication between the tank and the mixer, and the tank and the water supply.

8. In a concrete mixing machine, the combination of a mixer, a loading skip for charging aggregates into the mixer, a water tank to supply water to the mixer to combine with the coarser aggregates supplied by the loading skip, a water supply connected with the tank, a water supply means leading from the tank to the mixer, a valve automatically operable by the skip to open the communication between the tank and the mixer, and to close such communication, and a plunger in the tank operable by the skip to forcibly discharge water in the tank into the mixer.

9. In a concrete mixing machine, the combination of a mixer, means for supplying aggregate to the mixer, a water supply tank for the mixer, a piston in said tank, means to adjust the degree of movement of the piston for supplying the proper amount of water for the aggregate to the mixer, and means to operate said piston to forcibly discharge the predetermined contents of the tank into the mixer before the eQro hourldof mixingbegins. I.r In a concrete mixing machine, the combination of a mixer, means for supplying aggregate to the mixer, a water supply tank for the mixer, a piston in said tank, means to adjust the degree of movement of the piston for supplying the proper amount of water for the aggregate, means to operate said piston to forcibly discharge the predetermined contentsI of the tank into the mixer, and a water supply means connected with the tankto restore the piston to its normal position after it has been actuated as aforesaid.

11. In a concrete mixing machine, the combination of a mixer, a loading skip for charging the same with coarse aggregates, a water supply tank to supply a liquid aggregate to the mixer, means establishingl communication between the water tank and the mixer, and means operable incident to the charging movement of the skip for initially opening the communication between the tank and the mixer and for subsequently forcing the contents of the tank into the mixer.

12. In a concrete mixing machine, the combination of a mixer, a loading skip for charging the same with coarse aggregates, a water supply tank to supply a liquid aggregate to the mixer, means establishing communication between the water tank and the mixer, means operable incident to the charging movement of the skip for initially opening the communication between the tank and the mixer and for subsequently forcing the contents of the tank into the mixer, and water supply means connected with the tank and controlled by the means for opening communication between the tank and the mixer so that its supply is cut off when the contents of the tank are y passing to the mixer, and renewed when communication between the tank and the mixer is cut 0H.

13. In a concrete mixing machine, the combination of a mixer, a discharge means therefor, a batchmeter controlling said discharge means for determining a predetermined mixing period in the operation of the mixer, water supply means for the mixer, means for charging the coarse aggregates into the mixer, and means intermediate said parts whereby the batchmeter is set into action only after a predetermined quantity of water has been supplied by the tank to the mixer and after the said coarse aggregates have been charged into the mixer.

14:. In a concrete mixing machine, the combination of a mixer, a water tank to supply a predetermined quantity of water to the mixer, a batchmeter to control a predetermined mixing period for mixing operation, charging means for charging coarse aggregates into the mixer, and means intertermediate said charging means and the batchmeter and intermediate said charging means and the water tank such that the batchmeter is set into operation only after a predetermined quantity of water has been delivered by the tank to the mixer and after the eoarser aggregates have been delivered by the charging means into the mixer.

15. In a concrete mixing machine, the combination of a mixer, a water tank to supply a predetermined quantity of water to the mixer, a batchmeter to control a predetermined inixing period for a mixing operation, charging means for charging coarse aggregates into the mixer, and means intermediate said charging means and the batchmeter and intermediate said charging means and the water tank such that the batchmeter is set into operation only after a predetermined quantity of water has been dclivered by the tank to the mixer and after the coarser aggregates have been delivered by the charging means into the mixer, the said batchmeter comprising a locking and discharging means for the mixer controlled by said lock.

16. In a concrete mixing machine, the combination of a mixer, a batchmeter, a discharge for the mixer controlled by the batchmeter, a water tank to supply water to the mixer, charging means to supply coarse aggregates to the mixer, means for operating said charging means to charge the mixer, water supply means for the tank, valve means for opening communication between the tank and the mixer, operating means between said valve means and the charging means to actuate the valve means incident to charging operation of the skip, and means intermediate the charging means and the batchmeter for setting the batchmeter into operation after a predetermined quantity of water, suflicient for the whole batch in the mixer, has been delivered to the mixer along with all of the aggregates adapted to be supplied by the charging means.

17. In combination, a concrete mixing machine, a batchmeter governing the operationl thereof, water supply means, a part operable to allow a regular predetermined uantity of water to pass to the mixing mac line, and to supply added quantities of a required amount at will, and means to reset the batchmeter to commencement of its control operation cacn time thc said part is actuated.

18. In combination, a concrete mixing machine, a charging means therefor, water suppl v means, a part automatically operable by the charging means to allow a regular predetermined quantity of water to pass to the mixingmachine, a batchmeter governing the operation of the mixing machine, the said part being adapted to be manually operated to supply added quantities of requirtd amount of water to the mixing machine, and means to reset the batchmeter to commenctment of its control operation each time said part is manually operated.

19. In combination, a concrete mixer, charging means therefor, water supply means, means to operate the charging means to charge aggregates into the mixei', means operable on actuating the charging means to cause a full charge of water for a mixing operation to be added tothe aggregates charged into the mixer by the charging means, a mixer discharge, a lock therefor, and means set into operation as the charging means concludes its charging action to maintain the discharge in non-discharging condition and to then release it to enable itto assume discharging position.

20. In combination, a concrete mixer, a loading skip therefor, Water supply means, means to raise the skip to charge aggregates into the mixer, means operable on raising the skip to cause a full charge of water for a mixing operation to be added to the aggregates charged into the mixer by the skip, a mixer discharge, a lock therefor, and a batchmeter adapted to control the time of a predetermined mixing period and said lock, and set into action on lowering movement of the skip.

21. In combination, aconcrete mixer, a loading skip therefor, water supply means, means to raise the skip to charge aggregates into the mixer, means operable on raising the skip to cause a full charge of water for a mixing operation to be added to the aggregates charged intothe mixer by the skip, a mixed'discharge, and a batchmeter adapted to control the time of a predetermined mixing period, and set into action on lowering movement of the skip.

22. In a concrete mixing machine, in combination, a mixer, means for charging aggregates into the mixer, a water supply leading to the mixer and including means for meas- 100 uring a proper predetermined quantity of water for a batch of aggregates, and means to insure the entrance into the mixer of all of the said predetermined quantity of water required for a particular batch of concrete, at 105 the zero hour of the mixing period of such particular batch.

23. In a concrete mixing machine, in combination, a mixer, means for charging aggregates into the mixer, a water supply lead- 110 ing to the mixer and including means for measuring a. proper predetermined quantity of water for a batch of aggregates, and means to insure the entrance into the mixer of all of the said predetermined quantity of 115 water required for a particular batch of concrete, at the zero hour of the mixing period of such aarticular batch, the last mentioned means Veilig operable by the charging means.

24. In combination, a concrete mixe-r comprising a mixing drum, means for supplying aggregate to the drum, a water supply controlling valve, means for supplying definite predetermined quantity of water under the 125 control of said valve to the mixer, and manual and automatic'.instrumentalities for operating the valve under conditions of service.

25. In combination, a concrete mixing drum, a water supply tank therefor, a Water 130 supply line leading to a source ot' Water supply, valve mechanism governing the Supply ot Water Jfrom the line aforesaid to the tank, and from the tank to the mixing drum and including a control valve, a manual operating device tor said valve, and an automatic operating device for the valve together With charging means for the mixing drum cooperative with the said automatic device.

26. Mechanism .substantially as claimed in claim 25, characterized in that the automatic device is adapted for opening the water valve, and the manual device is adapted for both opening and closing said Valve.

ERICH H. LIGHTENBERG.

Images