US1931942A

US1931942A - Tandem paving apparatus

Info

Publication number: US1931942A
Application number: US536282A
Authority: US
Inventors: Emil L Tranaas
Original assignee: Koehring Co
Current assignee: Koehring Co
Priority date: 1931-05-09
Filing date: 1931-05-09
Publication date: 1933-10-24
Anticipated expiration: 1950-10-24

Description

Oct. 24, 1933.

E. L. TRANAAS TANDEM PAVING APPARATUS 3 Sheets-Sheet 1 Filed May '9. 1931 EMM L- mmm/:5-

Oct. 24, 1933. E. L. TRANAAS TANDEM PAVING APPARATUS s vsheets-sheet 2 4 Filed May 9. 1931 Oct. 249 1933. E. L. TRANAAs TANDEM PAVING APPARATUS Filed May 9. 1931 @sheets-sheet 5 Emu. 1.-- Tfr/www5- Patented oci. 24, 193s res ATEN'E' FFIC TANDEM PAVHNG APPARATUS ration Application May 9, 1931. Serial No. 536,282

c 9. Claims.

This invention relates to concrete mixing machines and more particularly to that type of machine employing a plurality of mixing drums wherein the aggregates, cement and water are introduced into one of the drums and mixed therein for a predetermined period of time, after 'which the material is transferred to the second drum and mixed in this drum for a second predetermined period of time and subsequently discharged therefrom in proper mixed condition, the advantage of this type of mixing machine `lying in the fact that the maximum output of the machine is substantially double that of the usual single drum mixer. In the copending application of Erich H. Lichtenberg, Serial No. 517,578, led February 21, `i931, there is described a concrete mixing machine having a pair of mixing drums arranged in tandem, in which machine there is embodied a timing device for controlling and synchronizing the operation of several parts of the machine, there being also provided a batchmeter which initiates the timing device into operation.

In this copending application there is utilize the charging action of the charging device for the iirst drum to set the batchmeter so that at the end of the mixing period as controlled by the batchmeter, the batchmeter will automatically function to discharge the contents of one of the drums and simultaneously set the timing device into operation. Under these conditions the machine is entirely automatic in its cycle of operation with the possible exception that the operator must lower the charging skip after it has been raised to charge the first mixingdruni. There is also employed a power discharge' unit for turning the discharge chute of each drum from discharging position.

In the device of the present invention there are embodied several of the general features found in the aforesaid copending application, but instead of the specially constructed mixer called for in the said application, the present invention is directed to instrumentalities permitting the usual type of mixer to be employed to produce the results advantageously procured inthe said copending application. To this end, it is proposed in accordance with the present invention, to interconnect two separate mixing machines of the usual type in tandem, one of the machines being provided with a timing device arranged for controlling and synchronizing the operation of the operating parts of both machines, there being provided a batchmeter on the so-called driving machine for initiating the timing device into operation, similarly as described in the aforesaid copending application. I The charging action oi the charging device of. the driving machine sets f the batchmeter vso thatat the end of the mixing -period of the driving machine as controlled by the batchmeter, the batchmeter will function to discharge the drum of the driving machine and simultaneously to set the Vtiming device into operation.` This drum of the driving machine discharges directly into the charging device of the 85 driven mixing machine, the said timing mecha- .nis'm being inter-connected with the discharge charging skip must be lowered by the operator 'Z5 after the charging operation has been completed.

A further object of this present invention is the provision of novel discharge means adapted to be used in connection with the drum of the driving machine, whereby the contents of the drum can be discharged after the mixing period directly and without loss into the charging device of the driven machine and which can be automatically Withdrawn from proximity to the said ehargingdevice which may then be operated without interference. Suitable and novel actuatl ing means for carrying out this object are also provided, as will be explained more in detail hereinafter.

In the drawings,-

Figure 1 'is a diagrammatic side elevation of a pair of mixing machines arranged in tandem and interconnected and operating in accordance with this invention, the rear machine constituting the driving machine, and the front, the driven machine.

Figure 2 is a cycle diagram disclosing the relative synchronized periods of operation of the several parts of the mixing machine.

Figure 3 is a perspective view of a part of the discharge instrumentalities of the driving machine, and

Figure 4 is a perspective View of auxiliary discharge mechanism employed in connection with the discharge instrumentalities of Figure 4.

Figure 5 is a diagrammatic view illustrating a modification of the coupling connections between both paving units, and wherein movement of the extension chute is used for controlling the operation of. paver unit B.

Figure 6 is a detail view of the connecting channel structure for coupling the paver units.

Figure 7 is still another modification of the controlling means between the paver units, wherein movement of the skip of one paver unit isl used to control the operation of the other paver unit.

Figure 8 is a sectional view of the channel structure, taken on the line 8-8 of Figure 6.

Figure 9 is a detail View of the bell crank lever shown in Figure 5.

Referring more particularly to the drawings, A indicates generally a paver which is coupled in tandem with a second paver, generally designated as B. The paver A, being provided with a control batchmeter and master power discharge instrumentalities, both being common to the two pavers and synchronizing the operation thereof, is herein referred to as the driving paver, as aforesaid, the paver B being the driven paver.

The pavers A and B are similar in their construction, and accordingly the details of paver A will be set forth rst. VThis paver is mounted on the endless traction devices 10, and is provided with a source of power 11 which operates the traction devices 10 and other operating parts of the machine. The charging instrumentalities embrace the charging skip 12 carried on the bracket 13 which is turnably mounted on a shaft extending through the bracket 13 adjacent the end thereof, there being a crank 14 positioned on this shaft and turning with the bracket 13. Secured to the skip 12 are the usual hoist cables, diagrammatically illustrated at 15, passing over the pulleys 16 and 17 and around the winding drum 18. Operation of the drum 18 and cable 15 raises the skip to the dotted line position shown in Figure 1.

The mixer A is provided also with a batchmeter 19, of standard construction and operation, such, for example, as that described and illustrated in VPatent No. 1,451,483 granted to Henry O. Winkler and dated April |10, 1923. This batchmeter 19 is actuated from a rod 20, which is engageable by the skip 12 -as the skip moves into its discharge position. This engagement of the skip with the rod 20 sets the batchmeter 19 through the operation of the crank 21 in the well known manner.

Mounted upon the paver is the constantly rotating mixing drum 22 which is adapted to receive the material discharged from the skip 12. Adjacent the drum 22 is a water tank 23 connected with the drum 22 by the line 24 controlled by a three-way valve 25, this valve being of any well known form of three-way valve adapted to control the passing of water from the tank 23 to the drum 22 and to control the admission of water to the tank for replacement purposes, the said water coming from a main line supplying the customary water. Such valve mechanism is known@ and described by Lichtenberg Letters Patent No. 1,525,100 issued February 3, 1925. This valve 25 is actuated'by engagement of the skip 12 `with the crank 29 during the course of lifting the skip 12, the crank 29 being connected with the valve 25 through the link 27 and to an intermediate crank 29 through the link 28.

It will b understood that the batchmeter 19 is intended to control for predetermined periods of time the mixing operation performed by the drum 22, and that the batchmeter 19 will, at the expiration of the predetermined time of the mixing period, operate to cause the discharge of the mixed contents of the drum 22. This is accomplished through the provision of power discharge instrumentalities in operative connection with the batchmeter 19. The power discharge unit is represented at 30, being connected with the batchmeter 19 through the rod 3l. This power discharge mechanism is of any well known type, and devices suitable for use in this connection are described and illustrated in the Robb Letters Patent No. 1,660,301, issued February 21, 1928, Webb Letters Patent No. 1,628,378, issued May 10, 1927, and Menningen Letters Patent No. 1,648,144, issued November 8, 1927. Briefly outlined, these power discharge devices comprise suitable gearing enclosed in the housing 30 and operated from the batchmeter 19 through rod 3l to control the operation of the discharge chute 32 which is turnably mounted in the discharge opening of the drum 22 so as to be opened or closed under corresponding operations of the power discharge unit as controlled from the batchmeter 19. During the'mixing period the discharge chute 32 occupies the position shown in dotted lines in Figure 1, thus closing the discharge opening of the drum 22 and preventing escape of the materials being mixed in the drum, When the batchmeter 19 trips at the expiration vof the predetermined mixing period, the power discharge device isl actuated to turn the discharge chute 32 into the full line position to permit the discharge of the materials from the drum. The connection between the power discharge device 30 and chute 32 is indicated by the rod 33.

This brings us, then, to a consideration of the operation of this paver, but since such operations are in general well known, a general outline thereof will be here suicient. The charging skip 12 is loaded with aggregates and the hoist drum 18 operated from the engine 11 to raise the skip l2 to its dotted line position in Figure 1. As the skip 12 is raised, the bell crank 29 is actuated to operate the valve 25 to permit introduction of a predetermined quantity of water from the tank '23 into the drum 22. As the raising of the skip is continued, the skip engages the rod 20 and sets the batchmeter 19 which controls the mixing period in the drum 22. Simultaneously with the setting of the batchmeter, which is somewhat before the skip 12 has reached its full discharge position, the power discharge device 30 is actuated to operate the discharge chute 32 to bring itinto the non-discharge position represented by the dotted lines. The skip 12 is then discharged into the drum 22 which mixes the :charge for the time set by the batchmeter, which, at the expiration of the time, trips and causes, through actuation of the power discharge device 30, the chute 32 to assume its discharge position, which permits the discharge of the now mixed contents of the drum 22.

The raising of the skip is accomplished through rotation of the drum 18, which is controlled through the action of the batchmeter 19. When the batchmeter is tripped to actuate the power discharge device 30, the rod 35 connecting the power discharge device 30 with the clutch mechanism 37 is actuated to engage the clutch 37 which rotates the drum 18, thereby raising the skip 12. As the skip raises, the crank 14 engages the lever 43 which actuates rod 42 by means of which the power discharge device 30 is actuated vthrough lever 39 and rod 38 to turn the discharge chute 32 .to non-discharging position.

It will be noted that there is provided a lever 34 suitably mounted on the rod 35, actuation of which lever will disengage the clutch mechanism controlling the lifting of the skip 12, and will permit the skip 12 to drop back into position to Y receive another charge of material for introducclutch disengages and the brake is automatically applied to hold the skip in its elevated position. Operation of the lever 34 then releases this brake to return the skip 12 to its loading position.

However, it will be seen that the paver A is connected with the paver B, and it has been explained that the operation of the paver B is controlled through the action of the batchmeter 19 mounted on paver A. From an inspection of the drawings it will be seen that connected'with the power discharge device 30 on the paver A is the rod 38 connected-to one arm 39 of the bell crank, which is fulcrumecl at 40, and which has its other arm 41 connected with a rod 42 with the lever 43 which is engageable by the member 14 carried on the skip bracket 13. The lever 43 is' mounted so that when it is engaged by the memloer 14 the upper end of the lever 4.3 will be depressed, the lower end carrying the rod 42 beingr correspondingly moved to the right to pull the arm 41 of the aforesaid bell crank to the right. To the end of this arm l1 is connected the rod a4, which is conneotedto a rod 45 through the adinstable coupling connection 46. r1`he rod 45 connects with a ,bell crank arm l11a corresponding with the arm 41, the bell crank arm 39a connecting with a rod 38a which is operatively connected with a power discharge device 39a similar to the power discharge device 30 previously referred to. It will be apparent that this power discharge device controls the discharge of the mixing drum of the paver B and is in turn controlled through the batchmeter 19 of-the paver A.

It will be also apparent that the drumy 22 of the paver A discharges directly into the skip 12a of paver B; it being apparent that the material charged into the skip 12a will be the wet slurry prepared in the drum 22 of paver- A. Since the required quantity of water may be introduced into the drum 22, no more Water would be required during the time of mixing in the paver B,

and accordingly paver B not necessarily has to he provided with a water tank as has already been described in connection with paver A. Because the standard paver unit B is originally equipped with a water tank, advantage may be taken thereof if desired. Therefore, a certain quantity of water, but not all necessary for a proper mix is introduced into the drum. 22 and a small amount of water is added into the drum 22a to the premixed concrete.

However, there are provided on paver B similar skip hoisting instrumentalities as have been men tioned in connection with paver A. The skip 12a is carried on the bracket 13a which carries thecrank member 14a entirely similar to the member 14 previously described, and operating in the` same way. The skip is actuated through the hoist cable 15a and the pulleysla'and 17a, and drum 18a, as above described. It may be desirable, however, to provide additional reinforcing means for supporting the skip 12a up from the ground especially in View of thefact that there isa rod hereinafter to be described connecting the two pavers together which might otherwise interfere with the action of the skip 12a. This additional supporting means will be mentioned in more detail hereinafter.

Since there is only one batchmeter required for the control of the operations, paver B is not provided with any member corresponding to the batchmeter 19, this batchmeter 19 acting as a master control.

However, the mixing drum 22al is continuously driven from the engine 11a, and the discharge chute 32a of the drum 22a is operative through the actuation of the power discharging unit a, and is rotative from its vdischarge position to its non-discharge position, and contrarily. The operation of this discharge chute 32a is effected through the provision of the rod 33a. Operated from the power discharge device 30a is the rod 43 connected to a bell crank 49, to which is also' connected the rod l12a which is connected with the lever 43a adapted to be engaged by the member 14a as the skip 12a is operated. There is also provided the drive shaft 36a carrying the clutch and brake device 37a controllable from the lever 34a, from the power discharge device 30a thru a rod 35a. The operation of this is similarto that described in connection with the correspending parts governing the control of the operation of the skip 12, so that when the skip 12a is brought up to its discharge position, the clutchv of the member 37a is disengaged and the brake automatically applied to secure the skip 12 in its discharge position. Operation of the lever 34a will disengage the brake and permit the skip 12a to return to its loading position.

It has been mentioned that skip 12a is supported away from the ground. For this purpose there is provided the supporting bracket which receives the skip 12a and holds the skip out of contact with the, ground. The bracket 50 is braced as indicated at 5l" from the end of the .frame of the paver B.

The payers A and B are inter-connected b means of the rods 51 and 52 provided with the adjustable connecting member 53.

The mixing drum 22a of the paver B discharges into the distributing bucket 54 mounted on the boom 55 in the usual way.

Figures 3 and a show details of the discharge chute and auxiliary discharge devices as used in connection with the drum 22 on paver A.

It will be seen from Figure 3 that the frame 57 of the paver A is open at the iront, and that the discharge chute 32 discharges through this opening. As previously mentioned, the power discharge mechanism 30 operates this chute 32 in response to the timing of the batchmeter 19. It-

will be seen that this is carried out through the connecting mechanism of Figure 3, which shows the chute 32 is turnably mounted upon the shaft 58, which is in turn lcarried in the supports 59 and 59a, which act as bearings for the shaft 58. The shaft 53 is provided with a connecting portion 60 conveniently formed integrally with the shaft 58, which portion 60 has a pin 61 connected with the link 62, which is connected in turn with the crank lever 63 operating in the' bushing 64 mounted on the frame 57, the crank lever 63 being turnably held in place in the bushing 64 by means of a pin 65. nected to the rod 66 operating in the sleeve 67,

the rod 66 being in turn connected with a driving shaft voperating from the power discharge device 30, which shaft terminates in the driving stud 68. This construction justA described is standard'con- The crank lever 63 is construction and forms no part of the present invention.

It will be seen that the link 62 terminates in a yoke 69 in which is secured the member 70 to which the crank lever 63 is connected by the pin 71. This member 70 is held in position in the yoke 69 by means of a pin 72 extending through the yoke and projecting beyond far enough to receive the crank 73 which crank is in the form of a bell crank, the elbow of which is turnably mounted on a shaft 74 carried in the standards 75 and 75a. The arm 76 of the crank '73 carries the link 77. This link terminates in an eye 78 through which is passed the cross bar 79 carrying the standards to the ends of which cross bar are secured the standards 80 and 80a. To the upper end of the standards 80 and 80a is fastenedy the auxiliary chute 81, which is in the form of a channel provided with the Vupstanding sides 82 and 82a, which serve as guides to retain the material being discharged from the drum 22.

Fitted within the opening in the frame 57 is the chute 83 which is adapted to receive the chute 32 when this chute 32 is turned to discharging position. The chute 83 is mounted stationarily in the opening in the frame 57.

It will be seen that when the chute 32 is moved to non-discharging position the crank lever 63 moves the link 62 outwardly. The movement of the crank lever 63 sets up corresponding movement in the bell crank 73 which actuates the link 77 to swing the auxiliary chute 81 into the dotted line position shown in Figure 4. The bottom of the chute '81 may be grooved as necessary to permit it to assume this dotted line position, at which time the member 84, which normally rests upon the sides 82 and 82a of the chute 81 is brought into close engagement over the discharge end yor the chute 83 to cut off any leakage of material from this chute 83 while the chute 32 is in nondischarging position` When the drum 22 is to be discharged at the end of the mixing period the power discharge mechanism 30 operates to turn the chute 32 into discharge position, with accompanying movement of the crank lever 63 and the bell crank 73, which returns the auxiliary chute 81 into full line position of Figure 4 beneath the auxiliary chute 83, thus removing the member 84 out of contact with the end of the chute 83, and permitting unobstructed ow of the mixed materials from the drum 22 through the

chutes

32, 83, and 81, without loss, into the charging skip 12a of the paver B.

The operation of this arrangement of pavers willbe clear from an inspection of Figures 1 and 2, the latter ligure showing diagrammatically the cycle of operations taking place when the mixers of Figure 1 are in actual operation. The steps of operation may be briefly described as follows:-

Assume that the batchmeter has been set and the skip has been loaded. After the set time, the batchmeter 19 releases, tripping the power discharge unit 30, which causes the discharge chute 32 and auxiliary chute 81, to automatically turn to discharge position; at the same time the skip hoist clutch 37 being automatically actuated through the power discharge unit 30 causes the loaded skip 12 to rise. The pin 56 on the skip 12 engages the lever 29 which opensthe valve A25, releasing water into drum 22. At approximately the same time, the lever 14 abuts the lever 43, thus pulling the rod 42 and lever 41 to the right, and, depressing the lever arm 39, thereby operates the rod 38 to turn the discharge chute 32 and auxiliary chute 81 into non-discharging position. This operation actuates the rod 45, and turns the discharge chute 32a of the drum 22a into discharge position and engages the skip hoist clutch 37a for raising the skip 12a.

Returning to the operation of the skip 12, as this skip approaches the upper limit of movement, it strikes the rod 20, pushing the rod lso as to set the batchmeter 19, and as the skip 12 reaches its upper limit of movement, it disengages the clutch 37 and applies a brake which holds the skip in raised position until it is released by hand operation of the lever 34.

As the skip 8 of paver B rises, it trips power discharge unit 30a, which turns the discharge chute 32a, into non-discharging position. Skip 12a is lowered by the operatorby means connected with the lever 34a. The pin 56 strikes crank 26 and shuts oir the water flow to the drum 22 and opens the flow from the main line to the water tank 23. At the desired time, the batchmeter 19 releases, tripping power discharge unit 30, causing the chute 32 to assume the discharge position to discharge the contents of the drum 22 into the skip 12a, the cycle continuing, and the batch nally being discharged into the bucket 54 for spreading upon the sub-grade.

It will therefore be seen that there is in this way accomplished a steady delivery of fully mixed concrete at intervals of half the time required for a single paver to accomplish the same amount of mixing capable of being performed by a single machine.

In Figure 5 there is shown another method for interconnecting both the paver units. The extension chute 81 of unit A is connected with a lever 100 on the paver unit B by means of a cable 101. This cable 101 runs inside a channel member 102, associated with the

necessary pulleys

103 and 104. The channel member serves the same purpose as the rods 51 and 52 in Figure 1. When the extension chute 81 is moved to non-discharge position, it pulls the lever 100 from full line position to dottedline position. The lever 100 moves about a pivot point 105 and compresses a spring 106. A roller 107 at the upper end of the lever 100 strikes a cam 108 mounted on a lever 109, raising the same and turning the shaft 110 and crank 111 mounted thereon. A rod 112, connecting the crank 111 with a bell crank lever 113, will be operated, and movement of the bell crank lever is used to operate a clutch yoke 114 to raise the skip 12a of paver unit B. The rod 35a of the paver unit B is eliminated in this construction.

When the roller 107 reaches its outermostright hand position the cam 108 and-lever 109 return to their full line position and the bell Acrank 113 renders the clutch yoke 114 free, which will then be returned by the paver discharge unit 30a upon completion of the mixing period of .the drum 22a, as previously described. When the extension chute 81 is returned to discharge position, the lever 100 is returned to the left or normal position by means of the spring 106. The

roller 107 strikes cam 108 and swings the cam member 108 around the pivot point 115 and out of its way without raising the leveri109 as cam 108 operates only lever 109 when the lever 100 is moved in a clockwise direction.'

By this method the discharge units are not connected, but the action is similar to that previously described. The clutch 37a is directly operated by a cable connected to the extension chute 81, and said 'chute is controlled by the discharge unit 30 of the paver A.

Figure 7 shows still another method of controlling the paver units A and B. Attached to the lever 43 is an arm 116 held against a stop 117 by means of a spring 118. A cable 119 connects said arm on the paver unit A with the discharge unit 30a on the paver unit B.

When the skip of the paver unit A' is raised, the

vcrank 14 strikes they cam 43, thus forcing the lever 116 away from stop 117, allowing the cable 119 to become slack. The spring 120 pulls lever 3.21 on the discharge unit 3a upwardly, operating the discharge unit and causing the chute 32a to move to discharge position. All the other operations are the same as previously described and illustrated in Figure l.

, The channel member 102, a detail of which is shown in Figures 6 and 8, comprises two

U-shaped channels

122 and 123 and

plates

124 and 125, connected together in any convenient manner, as by riveting or welding. Securing means 126 and 127 on the ends of the channel member serve for the purpose of connecting the same to brackets 128 and 129 on the paver units A and B.

A trough 130 may be mounted on the skip 12a as disclosed in Figure 1, into which the extension chute discharges the mixed material, thus preventing any dropping or loss of concrete.

It will be apparent from the above description that changes `in details of the apparatus specincally illustrated and described herein may be made without departing from the underlyingV inventive concept, and it will be apparent that such changes will readily suggest themselves to any one skilled in this art. 1t will be accordingly understood that it is intended and desired to emhrace within the scope of this invention such modications and changes as may be necessary to adapt it to varying conditions and uses.

Having thus described my invention, what I claim as new and desire to secure by Letters Patent ci the United States, is-

l. Concrete mixing apparatus comprising, in combination, two paving machines, the paving machines being interconnected to move together over a subgrade, and each having its own mixing and charging and discharging instrumentalities, the mixing instrumental-ities of one paver discharging into the charging instrumentalities of the other paver, means interconnecting the discharging instrumentalities of the two pavers for simultaneous but opposite action, and a timing mechanism operatively `associated therewith for operating the charging, mixing and discharging instrumentalities of both paving machines in a predetermined timed relationship whereby the combined machines perform a complete mixing cycle.

2. Concrete mixing apparatus comprising in combination, separate paving machines arranged in tandem, a mixing drum on each machine, chargingand discharging devices for each drum, a batchmeter for controlling the operation of the said devices, and a coupling means interconnecting the said devices of one drum with the devices of the other drum and arranged to be controlled by the batchmeter for operation of the respective devices of both machines in a synchronized predetermined timed relationship whereby the combined machines perform a complete mixing cycle.

3. Concrete mixing apparatus comprising, in combination, separate paving machines arranged in tandem,` each machine comprising a mixing drum provided with a discharge chute movable to charging and non-discharging positions, a charging skip and a power discharge device, the drum of one machine discharging into the skip of the other machine, means interconnecting the discharge devices for simultaneously operating the devices to move one chute in discharging position and the other chute to non-discharging position, a timing device on one of the machines for controlling the operation of the power discharge devices and raising of each charging skip, and means on each machine operated by the raising of each skip to actuate the power dis'- charge devices to turn the chute to non-discharging position.

4. Concrete mixing apparatus comprising, in combination, separate paving machines arranged in tandem, each machine comprising a mixing drum provided with a discharge chute-movable into charging and into non-discharging position, a charging skip and a power discharge device, the drum of one machine discharging into the skip of the other machine, means interconnecting the` discharge devices for simultaneously operating the devices to move one chute into discharge position and the other chute into non-discharging position, the said means comprising a connecting rod interconnecting the power discharge device on each machine, lever mechanism connecting the rod to each power discharge device, a batchmeter on one of the machines for controlling the operation of the power discharge devices and also the raising of each discharging skip, and means on each machine operated by the raising of each skip to actuate the power discharge devices to turn cach chute to nou-discharging positiorl,` the raising of each skip and operation of each power discharge device being controlled by the batchmeter in a cycle of predetermined time.

5. A concrete mixing apparatus comprising the combination with a paving machine having a mixing drum mounted on the machine and a discharge chute operable in the drum to charging and non-discharging positions, of means for operating the chute, a stationary chute coacting with the discharge chute to receive mixed aggregates therefrom when the discharge chute is in discharging position, a movable extension' chute cooperating with the stationary chute, and instrumentalities for moving the extension chute into operative and inoperative positions -as the discharge chute is operated into charging and discharging positions,

6. A concrete mixing apparatus comprising the combination with a paving machine having a mixing drum mounted on the machine and a discharge chute operable in the drum to charging and non-discharging positions, of instrumentalities for operating the chute, a stationary auxiliary chute coacting with the discharge chute to receive mixed aggregates therefrom when the discharge chute is in discharging position, a movable extension chute cooperating with the stationary chute and movable into and out of engagementtherewith, and an upstanding member carried on the chute for closely engaging the end of the stationary chute to prevent loss of material therefrom whenthe extension chute is moved out of engagement with the said stationary chute.

7. A mixing apparatus, comprising two paving machines, each complete in itself, and including mixing, charging, and discharging instrumentalities, devices interconnecting the said machines for simultaneous travel or movement, mechanisms on one of the machines for coordinating liti 6 the operations of the discharge and charging instrumentalities of the other machine, and an automatic moving extension chute carried by one of the machines adjacent its discharge instrumentality for conveying mixed aggregates from said discharge instrumentality to the charging instrumentality of the associated other paving machine, movement of the said extension chute being adapted to carry it out of the path of movement of the charging instrumentality into which it feeds or supplies mixed aggregates.

8. An apparatus as set forth in claim '7, in which the extension chute is combined with mounting means therefor to support said chute in position adjacent to its cooperating discharge instrumentality of the paving machine on which it is carried, such that the extension chute operates to prevent dripping from the said discharge instrumentalities. l

9. A mixing apparatus, comprising two paving machines, each complete in itself, and includ-- ing mixing, charging and discharging devices, clutch instrumentalities and devices interconnecting the said machines for simultaneous travel or movement, a movable extension chute carried by one of the nachines adjacent its discharge instrumentality' for conveying mixed aggregates from said discharge instrumentality to the associated other paving machine, automatic means to control the movement of the said extension chute to carry it outof the path of movement of the charging instrumentality into Which it feeds or supplies mixed aggregates, and means on one machine to automatically operate the clutch instrumentality of the other machine for coordinating and synchronizing the operations of the charging and discharging instrumentalities of the two machines.

EMIL L. TRANAAS. y

CERTIFICATE 0F CORRECTIQN.4

Patent No. l, 931,942.

` october 24, i933.

EMIL L. TRANAAS.

lt is hereby certified that errorvvappears in the printed specification of the abovey numbered patent requiring correction as that the said -Letters, Patent should be read with this correction therein that the same may conform to the record of 4, Ifor "dischargingf read charging; and

the casein the Patentr Office.

Signed and sealed this'Sth day of December,

`(Seial) follows: Page 5, line 1ii7, claim n. Y 193s.

ii. P. Hopkins Acting Commissioner oi Patents.