US3080152A

US3080152A - Hydraulically driven transit mixer

Info

Publication number: US3080152A
Application number: US803387A
Authority: US
Inventors: John W Lendved
Original assignee: Chain Belt Co
Current assignee: Chain Belt Co
Priority date: 1959-04-01
Filing date: 1959-04-01
Publication date: 1963-03-05
Anticipated expiration: 1980-03-05
Also published as: GB897941A

Description

March 5, 1963 J. w. LENDVED HYDRAUMCALLY DRIVEN TRANSIT MIXER 4 Sheets-Sheet 1 Filed April 1, 1959 l A l.

INVEN TOR. JOHN W. LENDVED March 5, 1963 J. w. LENDVED 3,080,152

HYDRAULICALLY DRIVEN TRANSIT MIXER Filed April l, 1959 4 Sheets-Sheet 2 FIG.2. 6.24

24 l AJ- it.

' mVENToR.

JOHN W. LENDVED Matth 5, 1963 J. w. I ENDVED HYDRAULIC/my DRIVEN TRANSIT MIXER 4 Sheets-Sheet 5 Filed April l, 1959 OQ Hayley Mmh 5, 1963 J. w. ENDS/ED 3,080,152

HYDRAULICALLY DRIVEN TRANSIT MIXER 4 Sheets-Sheet 4 Filed April l, 1959 INVEN TOR. JOHN W. LENDVED United States Patent O cousin Filed Apr. l, 1959, Ser. No. 8il3,387 1l Claims. (Cl. 259-171) This invention relates generally to transit concrete mixers and more particularly to a truck-mounted mixer having an improved power transmitting and control apparatus for driving the mixing drum.

Concrete mixers are conventionally mounted on the rear portion of a motor truck for transporting batches of concrete from a central source. The concrete mixers are rotatably mounted for mixing or agitating the concrete during the travel to the consumer.

Truck-mounted concrete mixers are so arranged that the mixing drum is either driven by a separate engine carried on the truck or by the internal-combustion engine of the truck.

The driving power for truck engine driven mixing drums may be taken indirectly from the truck engine through the main clutch and the usual power transmission mechanism or directly from the crankshaft of the engine. in the indirect power take-off, the speed of rotation of the mixing drum is directly rela-ted to the speed of the truck. Furthermore, when the main clutch is disengaged to shift the truck gears, the mixing drum stops rotating and must be restarted upon re-engaging the clutch. This makes gear shifting ditlicult. Furthermore, the mixing drum often turns backwards when the clutch is disengaged because of the unbalance load in the drum and interferes with rapid clutching and shifting of the truck. With such previously used mixer driving arrangement, the truck operator is not therefore free to utilize the truck motor to best advantage, particularly when diiicult driving conditions demand flexibility of operation and full power.

Some of the difficulties involved in the indirect power take-off from the truck engine to drive the mixing drum have been obviated by arranging a power take-olf connection directly to the engine without going through the main clutch.

Such connections are usually made at the front end of the truck engine where the crankshaft can be most readily connected to a separate transmission train. However, the transmission trains are relatively complicated and troublesome to install on the truck. Furthermore, truck mixers are mounted on commercial trucks of various kinds, and even though the trucks are quite similar in appearance and basic construction, differences in details of construction necessitate special mounting arrangements in adapting the mixer drum drive mechanism to each individual truck. This makes it diicult and usually impractical to transfer a mixer from trucks of one manufacturer to another.

A separate engine mounted on the truck for driving the mixer is therefore widely used.

The United States Patent 2,696,371 to I. W. Lendved discloses an improved and highly satisfactory separately mounted engine drive. As more fully disclosed therein, practically all governmental units establish weight limits than can be carried on the truck wheels of trucks employing the highways. Normally, the rear wheels are loaded to capacity prior to the front wheels. If a portion of the load can be shifted to the front wheels, an increased total load can be carried. The Lendved patent provides a separate engine mounted adjacent the rear portion of the truck to shift maximum weight onto the front wheels.

Separate engines requires suitable gear reduction and coupling to the mixing drum and normally substantially BQSZ Patented Mar. 5, 1963 increase the basic weight of the truck and mixer and reduce the pay load which can be carried in the mixer.

A mechanical drive coupling the drum to the truck engine or to a separate internal-combustion engine are practically exclusively employed in present commercial truckrnounted mixer. However, hydraulic drives for truckrnounted mixer are also available.

The known hydraulic drives generally employ a high speed hydraulic motor which is coupled to the mixing drum by a suitable gear or chain reduction system. The drives are relatively complicated and heavy. Consequently, such drives reduce the payload which can be carried and are relatively expensive in first cost and maintenance. Further, when the direction of rotation of the drum is to be quickly reversed the inertia in the drum establishes relatively large shock forces on the coupling system.

lt is therefore a general object of the present invention to provide an improved truck-mounted concrete mixer having an improved power transmitting system for driving the mixing drum of the concrete mixer.

Another object of the invention is to provide an irnproved mixing drum driving apparatus that may be installed readily on any of various supporting vehicles and which establishes excellent distribution of the payload between the several wheels.

Another object is to provide an easily controlled and smoothly operating lightweight power transmission mechanism for driving the mixing drum of a truck mixer from the truck engine.

Another object of the invention is to provide an improved hydraulically actuated power transmission mechanism for driving the mixing drum of a truck mounted concrete mixer from the engine of the truck.

Another object is to provide a combined driving motor and main bearing pedestal unit for the mixing drum of a truck mixer.

Another object is to provide an improved truck mounted mixer driving arrangement including a reversible, variable speed motor directly connected to the mixing drum.

Another object is to provide a directly connected driving motor for a concrete mixing drum so arranged that mixing water may be introduced into the drum through the shaft of the motor.

According to the invention, a truck mounted concrete mixer is provided with an improved power transmitting apparatus whereby the mixing drum may be readily driven from the truck engine or other power source preferably in either direction of rotation and at any desired speed within a preselected operating range. The improved apparatus of the present invention is hydraulically operated, is lightweight, directly and smoothly controlled through a suitable hydraulic flow control system and may be installed readily on trucks of various kinds.

The hydraulic transmission system in accordance with a preferred construction includes an eiiicient slow-speed reversible hydraulic motor that is mounted at the front of the drum and is directly connected to the drum head. Hydraulic iluid under high pressure is supplied to the motor through suitable flexible conduits from a variabledisplacement, reversible-flow pump that is driven preferably by the truck engine. The hydraulic motor is of the multiple-cylinder, radial type and its power shaft is connected to the drum head to constitute the mixer shaft. The motor bearings form the main bearing for the drum with the motor housing serving as the front bearing edestal. Since the fluid is pumped at high pressure, the lrequired power may be transmitted at low velocity thereby minimizing power losses and improving operating conditions. A simple control device mounted in the truck cab or elsewhere on the machine may be operated to adjust the pump for effecting rotation of the mixing drum in either direction at a selected speed.

In accordance with another aspect of the present invenltion, the motor is supported on the truck at a single point by means of a universal pivot support or 4ball joint to correspondingly support the adjacent end of the drum. The opposite endof the drum is supportedin the usual manner ona pair of spaced rollers.` The rollers and the ballitype jointy establishes a three-'point mounting systeml for the mixing drum which avoids stresses which might otherwiseeresult. from bending and twisting of the truck frame in operating lover roughpterrain.

The ball-type joint endofthe drum is stabilized on its single. support point by atorqueresisting.;` or stabilizing strutfthatis inter-connectedbetween the motorl and the truclgframefto prevent lateral swinging movement of the drum.

the motor is directly connected tothedrum end,` itreijuir'esllittle space thereby enablingthe drum to `be positionedforwardlyon the truck for best weight distribution.l l

Thehydraulic fluid circulates` inaclosed. circuit between'thepump and the motor, the circuit being so arranged that 'the motoroperates also as a brake to keep the'drum 4always under control whereby the drum maybe star-ted smoothly, reversed orstopped with minimum slio'clcl Since the power connection between the truck engine and the drum driving-motor may be effected through iiexible conduitsy the ,apparatus may be mounted in the most favorable positions onany suitable mo-tor .truck or Vtransferred from one truck -to another and the conduits installed; with minimum modification of the structure.

' The foregoing and other objects of this invention will.

become more fully apparent from the following detailed 4description of a preferred embodiment of an improved truck mounted concrete mixer constructed .in accordance with'the present invention. 4

'I'he drawings furnished herewith illustrate the best lInode presently contemplated for carrying out the invention. i

In the drawings:

FIG.l l'is a side elevational view with parts broken away of a'truck-mounted concrete mixer incorporating la pre,- ferred embodiment of the mixer drive in accordance with the" present invention;

yFIG. 2 is the fragmentary view taken upon a line 2,-2 ofFIG. l; i

FIG. 3 is -a view partlyin section and partly in elevation generally taken on line 3--3 of FIG. 2;

FIG. 4`is a front elevational'view of the hydraulic motor-shown in FIGS. 2 and 3 with the principal plane of the motor pivoted to a Vertical plane;

FIG. 5 is a cross section of a iluid distributing valve shown in FIGS. 1-3; and

FIG( 6` is a simplified diagrammatic circuit lof the hydraulic power system adapted to the drive shown in FIGS. 1'-5.

Referring to the Adrawings and particularly to FIG. l, a truck mounted concretev mixed constructed in accordancewith the present invention is shown generally including a mixing drum 1 which is rotatably mounted on the rear portion of a truck frame 2 of a conventional type truckl to form a truck mounted transit mixer adapted lfordeliveryand mixing of concrete, not shown.

The truck includes a pair of forw-ard front steering wheels 4 -andtandem rear wheels Swhich are connected to the frame `2 in any suitable manner to allow movement ofthe truck'. The frame 2 conventionally consists of a pair of .laterally spaced longitudinally extending channel members which. are interconnected to form a rigid andrm understructure for supporting the various operating members of the Vtruck andthe mixing drum. An int'rfnalcombustion yengine 6 is secured t-o the forward portionfof the'frame 2 and coupled to the rear wheels 5 througha ,conventional gear transmission unit 7 to supply` power'to the rear wheels S and movethe truck 3.

A cab 8 is secured to the forward portion of the frame 2 enclosing the engine 6 and the various steering and riding components of the truck 3 and provides -a protec- `tive enclosure for the truck operator, not shown.

The truck 3 is generally representative of vehicles which are presently made to carry a mixing drum 1 and the load or batchof concrete, not shown. The particular truck 3 is generally typical of various commercially availfable motor ,trucks although the various construction details may varyconsiderably. Generally, however, the back frame portions are formed substantially identical to each other to accommodate the various containers and structures which. are conventionally manufactured and secured to the-trucks by others..

Themixing drumlis generally anelongaltedtapered cyinder having an outer, tear drop.I configuration.

A plurality .otgcirctmifcrent-ially distributed spiral :vanes Qlare welded withinthe rnixingdrum 1 todischarge or, to the.concrete, not shown, inaccordance 'witlrthe4 directionofrotation of thedrurrrll,v as subsequentlyy de: scribed. The back end of the drum l is formed with an opening. l@ through which concrete is selectively admitted and discharged. A hopper 1i is mounted in communication, with-the opening itl 'toV directconorete intov lland `the conorete, not shown.: Hatclrl may alsobe.

employed for. charging `drum .1.

The .mixing drum l is rotatably vsupjmrted upon .the back portion of the frame 2 by a forward .drive .and bear, ing unit M anda rear bearing unit i5. lr6 are spaced in accordance with the members. offrarne 2- and welded orotherwise secured .tothe bearing units 14 and .15. The bearing units .I4 and lSiare. secured to.

frame 2 .with .theZ-bars ldrestingon the adjacent frame members to. support drum 1 extending. longitudinally of .the truck .3 .with .the headA of rear of cabs.

The rearfbearing unit V15 supports theback .end of the mixing drum l above the head of the drum to bias the concrete, not shown, to the .forward portion :of the mixing drum l. and thus maintain the maximum possibleweight toward the yforward o-r frontpart. of the truck 3 and thus on the front steering wheels 4.

The mixing drum il is thus adapted to be mounted on any one'of the various commercially available trucks and to be remounted upon a new truckA incident to damage or obsolescence of truck 3.

Z-bars Mare `secured to the truck frame 2 by a plurality of standard bolt and nut clamp `assemblies 117 to tiethe `back bearing unit 15 Yto the truck frame 2.

Theillustrated bearing unit 15 is generally similar tto thatshown in the previously referred to U.S. Patent No. 2,696,371 and comprises a 'box-like cro-ss brace 18V forming a bearing pedestal which extends upwardly and'A slightly. forwardly from the rear end of the Z-bars 16 and the frame 2. adjacent the rear par-t of the mixing drum 1. A pair` of laterally spaced rollers i9 'are rotatably mounted on the upper end of the cross brace i8 to rotatably support the rear or bacicv end of the mixing drum il. A ring -trackway Ztl is secured or otherwise formed on the outer circumference of the mixing drum 1 in alignment with the rollers Il. Afshield and bracket support 2l encircles the trackway Ztl as an extension from the cross brace 18.

A pair of rearwardlyprojected brackets 22, of which only one is shown, are Secured` to opposite sides of the the truckframe 2 to supportthe ffronft endof the drum 1" Ay pair `of Z-bars the .drum l .adjacent the f 4in the illustrated embodiment of the invention as follows.

Referring particularly to FiGS. l-3, a box-like arcuate bridge member 23 constituting a lateral mounting brace is secured between a pair of laterally spaced end or junction plates 24 which extend downwardly immediately adjacent the outer walls of the frame 2. The plates -24 flare forwardly and rearwardly of the bridge member 23 and are secured to the frame 2 by a plurality of bolts 25 to transmit the drum load to the frame 2v. A triangular foot member 26 constituting a load distributing brace is welded to the undersurface o-f the bridge meinber 23 and the adjacent plate 24 and res-ts on the upper Wall of the corresponding portion of frame 2 to distribute the load. The plates 24 are welded to the forward end of the Z-bars i6 to tie 4the forward bearing ld tothe rear bearing unit 15. A portion of the top wall of the Z-bars 16 is removed as `at 27 to accommodate the rearwardly =flared portion of plate 24.

A supporting socket member 2S of a two-piece balltype socket 29 inclu-des a depending bracket 3) which is welded to the top and the rear walls of the bridge ymember 23 midway between the plates 24. An upper retaining socket member 31 is releasably bolted to the bearing socket member 28 by a pair of oppositely disposed bolts 32, which extend through suitable openings in the member 28 and thread into correspondingly tappe-d openings in the retaining member 3l. The bearing member 23 is provided with a hemispherical recess opening vertically and rearwardly upwardly toward the mixing drum l. A

bearing ball 33 is disposed within the hemispherical ren cess and pivotally clamped therein by the retaining socket member 31 which has a correspondingly shaped recess.

The bearing ball 33 includes an integral shank 34 which extends vertically upwardly therefrom with the axis of the shank `and bearing ball lying in a plane which is perpendicularly related to the axis of the mixing drum 1. The shank 34% is secured within a corresponding opening in the forward drive and bearing unit ift- An encircling ange 3S is welded to the shank 34 adjacent the bearing ball 33 and is bolted as by bolts 3e to the forward drive and bearing unit which is thereby pivotally secured to the truck frame 2.

The bearing ball 33 in combination with the rollers 19 establish a three-point suspension for the mixing drum l and prevent the twisting of the truck frame 2 from being transferred to the forward bearing unit U. Consequen-tly, high stresses inthe frame of the front bearing unit 14 are prevented.

In the illustrated embodiment of the present invention, the forward bearing unit llil is a multi-cylinder, radial hydraulic motor which constitutes the forward rotating support for the mixing drum 1 and the power source to lrotate the mixing drum 1.

The bearing unit i4 generally includes a ring-shaped motor housing 37 4to which the bearing ball 33 is rigidly secured by flange 35 and boi-ts 36. A front closure and bearing plate 3S is removably secured to the ring-shaped housing 37 by bolts 3x9 to removably close the forward opening of the housing. An integral rear closure and bearing plate 4b closes the drum side of the ring-shaped housing 37.

A drive or crankshaft 41 is rotatably secured within the housing 37 by a front bearing 42 centrally located in the front closure and bearing plate 3S and a bearing 43 which is centraily located in the integrally formed rear closure and bearing plate 4d. The front bearing 42 is a conventional double roll radial bearing and the rear bearing 43 is a conventional tapered roller self-aligning roller bearing. As the bearings are conventional, no further description thereof is given.

The drive shaft 4l extends rearwardly through the bearing plate 4t) in alignment with the axis of drum l. The shaft 4l is rigidly coupled to the front end of the d mixing drum 1 to form the forward trunnion of the mixing drum l as follows.

Referring particularly to FIG. 3, a coupling hub 44 is secured to the forward wall 45 of the mixing drum 1. An annular plate member 46 is welded to the inner surface of the wall 45 and to the innerportion of the hub #i4 to rigidly support the hub on the mixing drum ll. The coupling hub 44 and the rearwardly extending portion of the shaft el are correspondingly splined as at d'7 to interlock the shaft 41 and drum i and cause simultaneous rotation. Suitable lock nuts 48 thread onto the innermost end of the shaft 4l, which is correspondingly threaded, to lock the hub i4 on the extended end of the drive shaft 4l. Consequently, rotation of the drive shaft 4i. is transmitted to the mixing drum 1 to rotate the concrete, not shown, which is supported within the drum.

The crankshaft 4l is provided with a central axial passage 49 which extends the complete length of the crankshaft and which is adapted to be connected to a water tank, not shown, which may be supported in any suitable manner on the truck, the forward bearing unit 14 or the like. In the illustrated embodiment of the invention, the opposite ends of the central Water passage 419 are closed by suitable cap assemblies 5t? and 5l which are releasably secured to the crankshaft 4l. rthe United States Patent 2,534,445 which issued to T. K. Hilkemeier on December 19, i950, discloses a particularly satisfactory construction for a water connection which may be readily applied to the illustrated crankshaft 41.

The ball-type socket 29 is secured to the motor housing 37 by the ball shank .34 somewhat forwardly of the principal plane through the housing 3'7 to substantially vertically align the rear bearing 43 with the ball .33. rl`he load forces transmitted to the frame 2 through the ball socket 29, particularly while braking the truck 3, include a horizontal component and a vertical component which combine into a resultant force extending angularly forwardiy and downwardly. The movement of the ball socket 29 forwardly, as shown, brings the line between the bearing 43 and the ball 33 more nearly in alignment with the resultant force and improves the transfer of the horizontal and vertical forces to the frame 2.

Referring particularly to FlGS. 3 and 4, a disc crank 52 is integrally formed on the crankshaft il and extends radially within the housing 37. The disc crank 52 is a circular member eccentrically arranged with respect to the axis of the shaft 4i such that rotation of the crankshaft 4l and the integeral disc crank 52 causes the true centerof the disc crank to define a circle about the axis of rotation. The outer periphery of the disc crank 52 is axially hanged as at 53 to establish a relatively wide ringlike surface spaced from the outer wall of the housing .37. The disc crank 52 is adapted to be rotated by a plurality of uid actuated pistons 54 which are slidably journaled within cylinders S5 radially aligned with the crank 52.

The illustrated fluid motor includes five cooperating pistons 54 and cylinders 55 which are successively powered to cause smooth and positive rotation of the crank 41. Although any number of cylinders can be employed, more than three cylinders are necessary to make the motor self-starting. An odd number of cylinders results in minimum variation in pressure for each revolution of the drum. Each piston and cylinder arrangement is identical in the illustrated embodiment of the invention and consequently only one is described in detail.

Each cylinder 5S is an elongated cup-shaped member which is secured within a tubular hub 56 formed in the motor housing 37 in alignment with the plane extending through the disc crank 52. The cylinder 55 includes an integral upper head 57 substantially closing the outer end of the cylinder. A stop ring 58 is secured within a suitable encircling recess on the inner portion of the cylinder 5S. The ring 58 extends radially from the cylinder 55 and mates with a corresponding recess formed on the inner-edge of thetubular hub 56 to prevent or limit the outward movement of the cup-shaped cylinder. A C- shaped clamp 59 encircles the cylinder 55 immediately adjacent the outer'end of hub 56 and rests or engages the outer end surface of the hub. The adjacent upper edge of clamp 59 and anadjacent enlargement of the cyiinder 55 are provided with correspondingly chamfered edges 69 such that tightening of the clamp prevents or limits inwardly movement of the cylinder S and rigidly clamps the cylinder within the hubi56.

A suitable opening 6l is provided in the head S7 of each cylinder 55. to receive a uid line 6.2- through which a .fluid 63, shown. in FIG. 4, is sequentially selectively admitted andy discharged. from the cylinder 55 to reciprocate the, pistons S4, and drive the disc crank 52v and attached crankshaft 41 as more fully described hereinafter.

The piston 54 is generallya cup-shapedmember which isslidablyv supported within the cylinders 55. Oil rings 64. substantially seal the sliding surfaces .between the piston S4. andi the inner wall of the cylinders 55; A piston o1' connecting `rod` 65 ispivotally secured tothe piston 54' and slidably coupled to the disc crank flange 53.

The piston end of connecting rod 65 and the adjacent surface Aof the piston. 54 are correspondingly spherically recessed totreceive a pivot ball 66. A ring retainer `67l isv secured Within the piston 54 and in. engagement with an enlargement 68 on the inner end ofthe piston rod by a-:suitable coil spring 69 and a split ring 70 torpivotally and resiliently couple the rod 65 to the piston 54.

"Ehe opposite end ofthepiston rod @Sis provided with anintegraltriangular shoe 7i having a bearing portion- 721wiuchy correspondsgenerally to the width of the crank flange 53 and extends circurnferentiallyl of the crank 52.- A radial projection '73 is formed on the outer periphery lofone side ofthe connect-ing rodshoe 72 `and a split clamp ring 74 having-aninwardly opening recess is dis-- posed; over the` projection toradial-ly couple the connecting rods yd5 inbearing engagement with thecrank 52,

Referring particularly to FIG. 4, the hydraulic motor is sho-wn with-the top anduj'sperl right cylindersconnected tol a source of high pressure as subsequently described to receivevuid and tornove the pistons S4 and Iattached bearing shoes 72 inwardly. The line of force on-crank 52 is off center with respect to-shait and thus the crank 52 rotates in 'a counterclockwise direction. The upper left cylinder 55 is on dead'centerY with its line of force' aligned with the center-of shaft dit and the true center of crank 52. The lower left and right cylinders' yare connected to the low pressure :side of the source, as subsequently described, to discharge the actuating iuid 63 and allow inw-ard movement of the corresponding Ipistons' 54. The cylinders' receiving and discharging iiuid are outof phase or step with each other to provide overlapping of the power cycles. The cylinders S5 are sequentially powerediwith the slight overlap in the `power cycle of adjacent cylinders to establish a smooth and continuous rotation ofthe crank 52.

To reverse the direction of rotation, with the motor in the state illustrated in FIG; 4, the two lower cylinders 55 are connected'to the high pressure side of a source land the-toptandY upper right cylinders are connected to the low pressure side of the source. Thus, the direction of rotation is controlled by the sequential direction in which fluid is applied to the successive cylinders 55. Consequently, successive actuation of the pistons Sd by .the incoming fluid 63 which is admitted via :duid lines 62 `and the, fluid openings 6l continuously shifts the position ofthe several shoes 72 and causes rotation of the crank 52i and the attached shaft 41.

The connecting -rods 65 oscillate slightly about the ball pivot 6 6 in accord-ance with the superimposed straight line motionaifected by the successive. cylinders to allow the simultaneousmovement of the shoes-'72m two rela.- tive directions.

A portion of the Iincoming iluid 63 to the cylinder 55 is. used to establish forced lubrication between the shoes 72 and the crank ange 53 and to thereby reduce the friction forces and allow smooth rotation of the crank 52. Radially aligned

oil passages

75, 76, and 77 are respectively formed in the piston 54, the pivot ball 6dl andthe connecting rod 65 to 'allow a relatively minute quantity of incoming fluid `63 to flow radially into the interface area between the bearing portion. 72 of shoe 71 and the crank flange 53. The. lubricating oilk flows 'between the bearing portion 72y of shoe 71 and the crank flange 53 of crank 52A and discharges: into they housing 57;

An oil drain 7S is4 secured to the lower end of the housing 37 to drain olf the accumulated lubricating duid and to return itv into the system, as subsequentlydescribed'.

The hydraulic motor thus serves to` rotate the mix-ing drum l as well as to simultaneously constitute the for werd bearing support for the mixing drum.

Referring particularly toV FIGS. 2 and' 3', at pair of superposed rigid torque resisting rods 79" and' girare pivotally secured at one end to the housing 37 andi at' the opposite end. to one of the ybearingplates 24 by suitable knuckle joints 81. Each of the knuckle joints. Si." includes a pair of inwardly extendingpins S2 secured to, the end of rods 79 and dit and toa bearing ball 83.'. The bearing balls 83 are mounted for universal pivotal' movement w-ithin` corresponding spherically surfaced openings formed in Ia pair of mating lugs Sd which' areV respectively welded tothe housing 37 rand mounting plate 24. The torque rods 79 and S0 prevent `lateralswinging of the drum and stabilize the mounting of the drum` 1L on pivot support 29.

Referring particularly to FIGURES l, 3` and 6,: the actuating fluid 63 supplied to the hydraulic motor cylinders S5 is preferably a low-velocity, high pressure fluid from asuitable fluid pump Svdri-ven by thetru-ckl engine 6. High working pressures create less heat loss, eliminating the need for a heat exchanger, and aregenerally more efcient. Further, the distributing system is simpler and the hydraulic motor can within practical limits be reduced in size. As a practical economic construction, 4000 pounds per square inchv presently ap-` pears to provide thebest design.

The pump S5' is mounted on the truck frame 2V adjacent the engine 6. A belt connection st connectsthe fluid pump 8:3 to a forward engine crankshaft extension for operation incident to running of the truck engine 6. The liuid pump 85 is preferably a variable-displacement re'- verse-iiow type pump of :the swash plate design which is commerci-ally available and is adapted to establish a low velocity, high pressure fluid ow. The pump 85 is -zherefore shown by a conventional lgraphical symbol in A fluid distributing valve 87, mounted on the hydraulic motor housing 37, is connected to the output of the liuidpump 85 by a pair of tnansporting

flexible conduits

88 and 89. The

conduits

88 and 89 selectively connected to thevhigh andl lou/pressure sides of the pump 55 for. forward and reverse rotati-onof the' mixing dri'i l.

Referring particularly to FIGS. 3 and 5, the valve-8'!l includes a housing 90 which is secured within an opening in the motor-housing 37. A' pair offspaeed inlet-

outlet ports

91 and 92 are provided in the exterior wall of the housing 90 and are coupled to the uid pipes 8S and@ and a plurality of distributing ports 93 are provided and connected to the several fluid lines 62 for carrying the fluid to cylinders 555. A rotatable valve drum 94- is journaled within the distributing valve housing 90 between the ports 91 and 92' and the ports 93. The. drum 94 includes suitable distributing passages 95which are adapted to successively connect the inlet-'outlet ports 9l'and'92'to the individu-al distributing ports`93 and' thus to thecylinders `55'. A drive Mjand extends outwardly through housingSd andinto the are alternatelyy shaft 9G is'secured to' the 'valvedrum motor housing 37. A gear 97 is secured to the extended end of the shaft 96 and is connected by a suitable idler gear 98 to a drive gear @9 which is secured about the hydraulic motor shaft lll. The gear 9d is rotatably mounted on the adjacent portion of the hydraulic motor and establishes timed synchronous rotation of the valve drum 94 with shaft 4l. Consequently, as the motor shaft 4l rotates the valve drum 9d is slowly rotated to successively connect the inlet-

outlet ports

91 and 92 to the distributing ports 93 to simultaneously supply high-pressure fluid 63 to certain of the cylinders 55 and to withdraw fluid from other cylinders.

The direction of rotation of the motor is determined by which of the inlet-

outlet ports

91 and 92 is connected :to the high pressure side of the pump 85. lf port 91 is connected to the high pressure side of pump 3d, the seuence of lluid application is in one direction, assumed arbitrarily to be in a counterclockwise direction as viewed in FIGURE 4. Then, it port 92 is connected to the high pressure side of the pump S5, the sequence of luid application to the cylinders 5S is in a reverse or clockwise direction. Consequently, the direction of rotation of drum l is easily and readily controlled in accordance with the operation of pump Se'.

The illustrated rotary valve is relatively simple and eliminates the shocks created by the conventional spool valve, the results of which are ditlicult and expensive to control,

The `hydraulic circuit may be formed in any conventional or desired manner. A simplified diagrammatic hydraulic how circuit is shown in FlGURE `6 for purposes of fully and clearly explaining the functioning of the present invention.

Referring particularly to FIGURE 6, the illustrated circuit is a closed-loop hydraulic system extending between the hydraulic motor and bearing unit lll and the pump 35. The truck engine 6 is connected to drive the fluid pump S5 which in turn is connected to the distributor valve S7 by the conduits 553 and 89.

A control lever lli@ is connected to the pump 8S by a suitable mechanical linkage or the like, as shown in PIG. l, and controls the direction of uid ilow through the pump and consequently determines the high and low pressure connection of the pump 5S to conduits S8 and 89. The control lever ldd has a forward position, shown in phantom to the right in the FIG. 6, and it is assumed for purposes of illustration that in this position, luid flow is through the pump S5 from conduit S9 to conduit SS and consequently conduit SS is connected to the high pressure side of tie ump 5S and conduit 89 is connected to the low pressure side or" the pump. The control lever ldd has a reverse position, shown in phantom to the left in FIG. 6, in which position a reverse luid low is established by pump $5 and the conduit 83 is now connected to the low pressure side of the pump and the conduit S9 is connected to the high pressure side.

The control lever litt when centrally located between the forward position and the reverse position, as shown, constitutes a neutral position wherein the conduits 8d and 39 are effectively disconnected from the pump SS and lock the fluid within the motor circuit.

The intermediate positions of the control lever jlttl between the neutral position and the full forward or reverse posi-tion throttles the fluid pressure and thereby regulates the speed of rotation of the mixing drum l. This provides a reliable stepless control giving an innite number of speeds within a predetermined range.

Further, when the hydraulic motor is operating in one direction and is to be quickly reversed, the mixing drum 1 is braked and establishment of high shock forces is eliminated. As the operator moves the control lever lll@ toward the neutral position, the uid flow to the cylinders 55 is progressively reduced and `the motor speed reduced accordingly. When the neutral position is reached, the fluid 63 is locked in the circuit and brakes the drum l to 19,- prevent large shock forces incident to the reverse positioning of the lever Mit).

The control of the direction and speed of rota-tion of the mixing drum is therefore simple and cannot be operated in a manner to cause damage to an expensive coupling system as in conventional mixing units. Consequently, unskilled personnel can be employed to operate the mixing drum.

The control lever ftd@ constituting a manual control is mounted within the cab of the truck 3 and connected to pump by a suitable coupling cable, not shown, to allow ready and convenient location of the control adjacent the operator, not shown.

A small oil reservoir lill is mounted on the truck 3 and connected to the crankcase drain 78 to collect the lubricating oil by-passed through the hydraulic motor, as previously described. Because the hydraulic power system to the motor and bearing unit 14 is a closed loop, the reservoir 161 is small and does not add appreciably to the weight ofthe truck and mixing components.

A make-up pump M2, shown in FIG. 6, connects the oil reservoir lill to the lluid conduits 3S and 89 to make up or return the withdrawn huid into the system and thereby to maintain a constant volume in the closed loop between the motor and the pump S5. Check valves 193 and ldd are connected in parallel 'between each of the

conduits

88 and 39 and the make-up pump ltlZ to prevent a reverse llow of fluid from the corresponding conduits. Consequently, the volume of fluid within the closed loop driving the hydraulic motor is maintained at a constant value.

A suitable pulley connection connects the makeup pump lli?. to the engine 6 for operation of the makeup pump whenever the hydraulic motor is operated. The pump to2 and connecting conduits are only shown in FIG. 6 for clarity of illustration.

The present invention provides a motor for directly driving the mixing drum l from the truck engine 6 without the necessity of complicated power transmission apparatus which is both diicult to install and maintain. The speed of the mixing and discharging can be independently established with a continuous and line adjustment within a relatively wide range through a simple and economic control unit. The term mixing is broadly employed in the present application to define the conventional mixing of the aggregate to form the concrete and also the normal agitation of a premixed concrete which is disposed within the drum for transportation.

Thus, the drum may readily be rotated from 0 up to l5 or i8 revolutions per minute while maintaining normal engine speed. The vdrum l can therefore be rapidly rotated to discharge the concrete while the truck is moved forwardly at a relatively lOw speed.

The direct connection of the hydraulic pump to the engine establishes independent operation of the mixing drum and the propulsion of truck 3. The starting and the stopping of the truck and the changing of the truck driving gears can be readily and rapidly controlled in the most advantageous manner. Further, the truckmounted mixer of the present invention can be operated without any substantial training without clashing of the gear and destruction of the clutch.

The combined bearing and driving motor of the present invention allows a most advantageous distribution of the weight ot the truck, mixing apparatus and the concrete contained therein upon the truck wheels such that the percentage of the total weight applied to the rearward wheels is maintained at a minimum. Consequently, an increased total load can be carried.

The mixing drum of the present invention is readily mounted on any conventional truck vehicle and is readily interchanged to a new truck whenever necessary.

The direct interconnection of the hydraulic motor as a forward bearing unit reduces the number of separate components mounted on the truck and interconnected ege-sai 1l with the' drum and permits a more modern design of a truck mounted mixer.

Various modes of carrying out the invention are contemplated as being within the scope of the following claims particularly pointing out and distinctly claiming the subject matter which is regarded as the invention.

-I'claim:

l. A drive mount for a tubular shaped mixing drum havin-g laclosed end for mounting on' the frame of a truck, whichl comprises a hydraulic motor includinghousf ing' and a driven shaft rotatably mounted in the housing, means to connect the driven shaft to 4the elo-sed end of the mixing drum to rotate the mixing drum, and a universal pivotl support secured to the housing and having attachment means for securement'lto the frame of the truck toy transmit the concentrated load presented at the'closed end ofthe drum directly to the frame.

2. A drive mount' for a tubular shaped mixing drum havinga closed end for mounting on the channel frame of a truck, which comprises a hydraulic motor including a housing and a driven shaft rotatably mounted in the housing, meansto connect the driven shaft to the mixing drum-to rotate the mixingV drum, a universalpivot supp-ort secured to the housing', and attachment means secured to the pivot support and including sidel plate members; extending downwardly adjacent the outer Vsurfaces of the' frame and having bolt receiving means for bolting of the side plate'members to the frame of' the truckto transmit the concentrated load presented at the' closed'end of the drum directly to the frame in thev assembled position.

3'. -A truck-mounted` concrete mixer includingv a concrete mixing drum adapted to be rotatably mounted on a frame of a conventional motor truck having a running controly transmission and an engine operatively connected to drive said contro-l transmission, said mixingv drum being closed at its forward end and open at its rear- Ward end, whichj comprises-a variable displacement reversible-iiow high-pressure pump operatively' connected to' be driven by'said truck engine independently of said running control transmission, control apparatus arranged to Vcontrol said pump'as to volume and' direction of fiuidow therefrom, bearing means disposed to rotatablysupport said open rearward end of said drum, a multiradial-cylinder hydraulic motor having a rotating shaft secure'd'to the closed forward'end ofthe drum, a ball a'ndsocket joint disposed to support said hydraulic motor ou said motor truck at a single point for universal pivoting movement thereon, a torque-resisting strut interposed between said hydraulic motor and said truck' to stabilize iSaidfmotor and said mixing drum` in operating position while permitting relative movement between said mixing drum and said truck to accommodate deflections of said truck, and flexible fluid conduits' sequentially conn'ectedr4 between said'high pressure pump and the cylinders ofsaid hydraulic motor to drive said mixing drum in either direction at desired speed incident to predetermined actuation of saidl control apparatus.

4; In a transit mixer for transporting and mixing a batch of concrete or the like including a motor truck having a drive engine on one end of the truck and a mixing drum rotatably mounted on the opposite end of said truck for receiving a batch ofconcrete to be transported, ak high pressure reversible hydraulic motor having a rotating.' member rotatable at the velocity range of the mixing drum, said rotating member being directly connected to the'engineend of said mixing drum to directly rotate the drum at the' sameV angular velocity as the motor, a high pressure variableV capacity pump operatively connected to'be driven by said truck engine and to drive said hydraulic motor, and control apparatus operatively connected to adjust 'said variablecapacity pump in a manner to regulate' the speed and'direction of rotation of said mixing" 'drum'. c

5: In' a' transit concrete mixer' of the' type having a rotatable mixing drum carried by a self-propelled vehicle having a driving engine, a Variable capacity reversing ow pump connected to be driven by said vehicle driving engine independently of the'l vehicle propulsion connection of said engine, manually operable control means arranged to adjust said pump to supply pressure fluid at selected rate in selected direction of ow from saidl pump, a hydraulic motor directly connected to said mixing drum to rotate the drum at the same velocity as the hydraulic motor, fluid conduit means operatively connecting said variable capacity reversing ow pumpl to said hydraulic motor whereby said rotatable mixing drum may be driven in either direction as predetermined speed selectively by controlling said pump independently' of the propulsion of said vehicle, andI a universal joint secured to the truck and thelhydraulic motor and constituting the support for the adjacent end of the drum.

6. In a motor-truck transit mixer having a driving engine on one end of the truck and having a concrete mixing drum rotatably mounted on the opposite end of the truclt for containing a batch of' concrete and transporting the batch of concrete, a slow speedA hydraulic motor having a motor housing and a power rotated member directly connected to said mixing drum adjacent said engine, a ball socket joint mounting said motor housing on said truck to rotatably support the drum, a variable capacity hydraulicpump mounted adjacent the engineand operatively connected to be driven by said truck driving engine, fluid conduit means interconnecting said pump and said'hydraulic motor to selectively drive the rotatable member of the motor and attached drum incident to said pump being driven by said engine, and' control means operatively connected to adjust the pumping capacity of said pump thereby to regulate the iiuid pressure to said motor to regulate the speed -of rotation of said mixing drum. l

7. In a transit concrete mixer, including va vehicle having spaced running wheels secured to a yieldable frame subject to deiiection when operating overuneven terrain; av mixing drum closed at one end and open at the other end to receive a batch of concrete to be mixed and transported and adapted toV be secured to theframe close to certain running wheels and spaced'from other running wheels, a motor provided with a protruding drive shaft that is rigidly xed to the closed end of said mixing drum in a manner to rotatably support said drum end and to rotate the drum, means arranged to support said motor on said vehicle frame for universal relative movement to accommodate deiiection of said frame, means arranged to support said open end of said drum for rotation on said frame in a` manner to accommodate deiiection of said frame, and a torque arm connected between said frame andsaid universally mounted motor to maintain said motor in position relative to said framey for supporting said closed end'of said drum for rotation on said frame, the arrangement being such that said drum may be rotated as said vehicle vtraverses uneven terrain without detrimental effects upon said drum or its driving motor resulting from deflection of said yieldable frame.

8. In a transit concrete mixer including a wheeled conveyance having a yieldable frame, a mixing drum for transporting and mixing concrete, said drum being open at one end and presenting an axially disposed shaft at-the other end, a pair of spaced rollers rotatably mounted on said yieldable conveyance frame in a position to support the open end of said mixing drum, and a `drum driving motor comprising a stator and a driven rotor mounted with said driven rotor rigidly connected to said shaft of said drumy and with said stator mounted for universal movement on said yieldable conveyance frame and constituting the support for the corresponding end of the drum, the arrangement being such that said mixing drum and said motor are rigidly interconnected as a unitary structure that is'mounted at vthree points on said yieldable frame whereby weaving of said yieldable frame may occur as said conveyance moves over uneven surfaces.

9. A drive mount for a tubular shaped mixing drum having a closed end for mounting on the channel frame of a truck, which comprises a hydraulic motor including a relatively stationary housing and a driven shaft rotatably mounted in the housing, means to connect the driven shaft to the mixing drum to rotate the mixing drum, a ball pivot support having a ball member and a socket member one of which is secured to the housing, a lateral mounting `brace secured to the opposite member of the pivot support, and junction plates secured to the brace and adapted to project downwardly adjacent the outer surfaces of the frame with the brace resting on the frame and adapted to be lbolted to the frame of the truck to transmit the concentrated load presented at the closed end of the drum directly to the frame.

10. A drive mount for a tubular shaped mixing drum having -a closed end for mounting on the channel frame of a truck, which comprises a hydraulic motor including a relatively stationary housing and a driven shaft rotatably mounted in the housing, means to connect the driven shaft to the mixing drum to rotate the mixing drum, a ball pivot support having ta ball member and a socket member one of which is secured to the housing, a lateral mounting brace secured to the opposite member of the pivot support, junction plates secured to the brace and projecting downwardly adjacent the outer surfaces of the frame in the assembled position and being bolted to the frame of the truck to transmit the concentrated load presented at the closed end of the drum directly to the frame, and load distributing braces secured to the mounting brace immediately adjacent said junction plates and resting upon the adjacent members of the channel frame of the truck.

11. In a concrete mixer having a generally tubular mixing drum mounted on a truck frame and rotated about the axis of the drum, a radial hydraulic motor having a housing with a plurality of circumferentially distributed cylinders lying in a common plane and pistons in said cylinders directly coupled to drive a crank and a shaft centrally journalled in forward and rear bearings in said housing, said shaft extending perpendicular to said common plane, means to rigidly couple the motor shaft to the drum in alignment with the drum axis, universal support means secured to said truck frame and to said motor in slightly spaced forward relation to said common plane to establish a substantially vertical line extending between the rear bearing for said shaft and said support means, and bearing means secured to said frame to rotatably support the opposite end of the mixing drum with the axis of the drum extending downwardly therefrom in alignment with the motor shaft.

References Cited in the le of this patent UNITED STATES PATENTS 1,547,409 Cacaud July 28, 1925 2,098,214 Benedek Nov. 9, 1937 2,256,324 Orshansky Sept. 16, 1941 2,350,285 Maxon May 30, 1944 2,511,240 Bohmer et al. lune 13, 1950 2,530,241 Harrington Nov. 14, 1950 2,541,228 Fitzgibbon Feb. 13, 1951 2,563,336 Jaeger Aug. 7, 1951 2,572,058 Sarasody Oct. 23, 1951 2,611,649 Johnson et al Sept. 23, 1952 2,624,557 Gerst Jan. 6, 1953 2,639,586 Muller May 26, 1953 2,706,623 Styes Apr. 19, 1955 2,732,189 Gerst Jan. 24, 1956 2,787,065 Bock et al. Apr. 2, 1957 2,812,638 Timms Nov. 12,1 957 2,901,975 Grad Sept. 1, 1959 FOREIGN PATENTS 464,044 Germany Aug. 7, 1928

Claims

3. A TRUCK-MOUNTED CONCRETE MIXER INCLUDING A CONCRETE MIXING DRUM ADAPTED TO BE ROTATABLY MOUNTED ON A FRAME OF A CONVENTIONAL MOTOR TRUCK HAVING A RUNNING CONTROL TRANSMISSION AND AN ENGINE OPERATIVELY CONNECTED TO DRIVE SAID CONTROL TRANSMISSION, SAID MIXING DRUM BEING CLOSED AT ITS FORWARD END AND OPEN AT ITS REARWARD END, WHICH COMPRISES A VARIABLE DISPLACEMENT REVERSIBLE-FLOW HIGH-PRESSURE PUMP OPERATIVELY CONNECTED TO BE DRIVEN BY SAID TRUCK ENGINE INDEPENDENTLY OF SAID RUNNING CONTROL TRANSMISSION, CONTROL APPARATUS ARRANGED TO CONTROL SAID PUMP AS TO VOLUME AND DIRECTION OF FLUID FLOW THEREFROM, BEARING MEANS DISPOSED TO ROTATABLY SUPPORT SAID OPEN REARWARD END OF SAID DRUM, A MULTIRADIAL-CYLINDER HYDRAULIC MOTOR HAVING A ROTATING SHAFT SECURED TO THE CLOSED FORWARD END OF THE DRUM, A BALL AND SOCKET JOINT DISPOSED TO SUPPORT SAID HYDRAULIC MOTOR