Title:
Apparatus for rotatably driving and supplying water to a mixing drum
United States Patent 3912239


Abstract:
Apparatus for rotatably driving and supplying water to a concrete mixing drum which includes a driving member secured to an end wall of the drum concentric with the axis of rotation and power means drivingly engaging the driving member to rotate the member and drum. An annulus having a continuous internal recess and at least one water inlet is slidably received on and circumferentially encloses a portion of the exterior surface of the driving member. The recess of the annulus bounded by the annulus and the enclosed portion of the driving member provides a water supply chamber. Water passages through the driving member provide fluid communication between the water supply chamber and additional water passages through the end wall of the mixing drum whereby water supplied through the annulus inlet may be delivered through the passages in the driving member and the end wall of the mixing drum to the interior of the mixing drum. Sealing means provided between interfacing surfaces of the driving member and annulus provide a fluid seal at each side of the water supply chamber while permitting relative movement between the annulus and the driving member.



Inventors:
RIES DONALD L
Application Number:
05/534460
Publication Date:
10/14/1975
Filing Date:
12/19/1974
Assignee:
ROCKWELL INTERNATIONAL CORPORATION
Primary Class:
Other Classes:
366/60
International Classes:
B28C5/42; (IPC1-7): B28C5/42; B28C7/14
Field of Search:
259/177R,177A,164,168,176,3,14,15,16,161,162,175 277
View Patent Images:
US Patent References:
3851862CONCRETE DRUM DRIVE SUPPORT1974-12-03Mihulowicz
3534891DISTRIBUTOR FOR GRANULAR MATERIALS1970-10-20Bozich
2793657Three-way water valve assembly for concrete mixers or the like1957-05-28McCullough
2563336Means for supporting and driving mixer drums1951-08-07Jaeger
2401431Painting machine1946-06-04Lewis



Primary Examiner:
Jenkins, Robert W.
Claims:
What is claimed is

1. Apparatus for rotatably driving a mixing drum and supplying fluid thereto comprising

2. The apparatus defined by claim 1 wherein a continuous recess is provided interiorly of said annulus and said water chamber is formed by said recess bounded by said circumferentially enclosed portion of said driving member.

3. The apparatus defined by claim 1 wherein said fluid passage means through said driving member includes an annular recess in said driving member bounded by said end wall of said drum and a plurality of fluid passages having one end open to said water chamber and the other end open to said annular recess.

4. The apparatus defined by claim 3 wherein said fluid passage means through said end wall comprise a plurality of circumferentially spaced openings through said wall and said annular recess provides fluid communication between said fluid passages through said driving member and said openings.

5. The apparatus defined by claim 1 wherein said annulus includes first and second leg elements defining a recess therebetween, said leg elements include surfaces proximate their respective ends which slidably engage axially spaced annular portions of said driving member, said water chamber is formed by said recess bounded by said leg elements and said driving member between said axially spaced annular portions, and sealing means between said end surfaces of said leg elements and said axially spaced portions of said driving member, said sealing means permitting relative movement between said driving member and said annulus.

6. The apparatus defined by claim 5 wherein said driving member comprises a flange having a drum end wall abutting surface on one axial side and a stepped hub extending axially outward from the other side of said member, said stepped hub including first and second concentric cylindrical surfaces, and said end surfaces of said first and second leg elements of said annulus respectively slidably engage said first and second cylindrical surfaces.

7. The apparatus defined by claim 6 wherein at least one circumferentially extending groove is provided to each of said cylindrical surfaces and sealing means are disposed in said grooves to seal between said end surfaces of said leg elements and said cylindrical surfaces.

8. The apparatus defined by claim 6 wherein the diameter of one of said cylindrical surfaces is greater than the diameter of the other cylindrical surface, the cylindrical surface of greater diameter is axially positioned between said flange and said other cylindrical surface, and a plurality of fluid passages through said driving member open into said water chamber through circumferentially spaced ports radially located between said cylindrical surfaces.

9. The apparatus defined by claim 8 wherein an annular recess is provided to the drum end wall abutting surface of said driving member, said annular recess being located radially inward of said flange, and said fluid passages through said driving member open into said annular recess.

10. The apparatus defined by claim 9 including an annular groove in said end wall abutting surface radially outward of said annular recess and sealing means axially compressed in said groove between said driving member and the end wall of said drum.

11. The apparatus defined by claim 1 wherein said means drivingly engaging said driving member comprises a transmission including power input means and an output shaft mounted for rotary movement, said output shaft extending axially outward from means mounting it for rotary movement, said driving member comprises a flange having a drum end wall abutting surface on one axial side and a hub extending axially outward from the other side of said member, said annulus is slidably received on said hub, sealing means disposed between said annulus and said hub on axially opposite sides of said water chamber permitting rotary and axial movement between said driving member and said annulus, means drivingly connecting said hub to said axially extending output shaft, and means associated with said output shaft mounting means for limiting axial movement of said annulus in one direction relative to said hub.

12. The apparatus defined by claim 11 wherein said transmission comprises a gear train supported by a stationary housing, said output shaft extends axially outward from rotary mounting means supported by said housing and an end surface of said housing supporting said rotary mounting means limits axial movement of said annulus in a direction away from said flange.

13. A coupling assembly for rotatably driving an end wall of a mixing drum and supplying water to passages provided through the end wall comprising

14. The coupling assembly defined by claim 13 wherein said water chamber is formed by an interior recess of said annulus bounded by said hub.

15. The coupling assembly defined by claim 13 wherein said annulus includes first and second leg elements defining a recess therebetween, said leg elements include surfaces proximate their respective ends which slidably engage axially spaced annular portions of said hub, said water chamber is formed by said recess bounded by said leg elements and said hub between said axially spaced portions, and sealing means between the end surfaces of said leg elements and said axially spaced portions of said hub permitting relative movement between said annulus and said hub.

16. The coupling assembly defined by claim 13 wherein said water passage means through said driving member includes a plurality of passages through said member and each of said passages open at one end into said water chamber and at the opposite end into a annular recess in said one axial side of said driving member radially inward of said flange.

17. The coupling assembly defined by claim 16 including an annular sealing ring recess in said one axial side of said driving member located radially outward of said annular recess forming part of said water passage means through said driving member.

18. In a transit mixer for transporting and mixing a load of concrete or like material including a motor truck and an elongate mixing drum mounted at one end of said truck for rotation about an axis of said drum,

Description:
BACKGROUND OF THE INVENTION

This invention relates to a drive arrangement for concrete mixers and more particularly to a coupling assembly for rotatably driving and supplying water to a mixing drum mounted on a motor truck.

Concrete mixers are conventionally mounted on the rear portion of a motor truck for transporting batches of concrete from a central source to a construction site. The mixers, generally in the form of an elongate drum, are rotatably mounted for mixing or agitating the concrete during travel to the site and while waiting for the load to be poured.

As the concrete is being mixed it is often necessary to add water to maintain the viscosity of the batch at a satisfactory level for pouring and working at the site. Water may also be added to the drum after the concrete has been poured to clean the interior of the drum. For these purposes, transit mixer trucks are usually equipped with water storage tanks and hoses or other conduits for delivering water to the mixing drum. The mixing drums are conventionally mounted for rotation about an inclined axis and water is normally introduced through one end of the mixing drum, usually through the end of the drum where it is rotatably driven.

The mixing drum may be driven by a separate engine carried by the truck or by the truck engine through a power take-off and transmission drivingly connected to the mixing drum. Two common transmissions employ a large gear or sprocket secured to the drum and respectively driven by a pinion gear or a chain and small sprocket mounted on the output shaft of a power take-off or auxiliary engine. In such systems water may be delivered to the drum by means of a hose inserted through the concrete discharge port or through a fluid passage provided axially through the shaft supporting the gear or sprocket secured to the drum. Several other arrangements for rotatably driving and supplying water to a transit mixing drum by means of a passage through a shaft in the driving mechanism are disclosed in U.S. Pat. Nos. 2,563,336 issued Aug. 7, 1951; 2,669,131 issued Feb. 16, 1954 and 3,080,152, issued Mar. 5, 1963.

Although the prior art chain and sprocket and gear driving and water supply arrangements have been widely adopted and have enjoyed extensive use, there are certain disadvantages to these transmission systems. Such transmissions, if left exposed, constitute a substantial safety hazard and therefore should be enclosed by safety guards to minimize the possibility of injury to workmen in the area. Moreover, although the chain drive has achieved the greatest degree of acceptance, this drive requires a certain slack in the chain which when taken up against the weight of the concrete loaded drum produces a reactionary force of sufficient magnitude to shake or tip the truck on its suspension. The chain drive also requires substantial maintenance.

The foregoing disadvantages demonstrate the need for a positive mixing drum driving mechanism such as an enclosed speed reducing gear train which requires relatively little maintenance and provides greater safety, higher efficiency and longer unit life. Any of a number of enclosed speed reducing gear trains could be adapted by suitable coupling means to rotatably drive a transit mixer drum, but such transmissions have not heretofore normally included means for delivering fluid such as water to the member driven by the output shaft of the transmission. The concept previously adopted in the transit mixer art of providing a fluid passage axially through the drum driving shaft is not readily adaptable to a compact enclosed speed reducing gear train transmission. Such an approach would require fluid passages through more than one member and fluid seals within the transmission housing which would be susceptible to wear and deterioration. In the event of water leakage through an internal seal the transmission would have to be disassembled to replace the seal.

It is therefore an important object of the invention to provide an improved apparatus for rotatably driving a concrete mixing drum and supplying water thereto.

It is also an object of this invention to provide a coupling assembly for coupling the output shaft of a power transmission such as a speed reducer to the end wall of a rotatable mixing drum and for supplying water to passages provided through the end wall.

It is a further object to provide a water supply arrangement for a rotatable mixing drum in which the water is delivered through the driving member in a simple efficient manner and which does not require a water passage through the output shaft of a power transmission or fluid seals in the transmission.

SUMMARY OF THE INVENTION

The novel rotatable driving and water supply apparatus of this invention attains these and other objects and advantages through the combination of a rotary driving member and an annulus adapted to be slidably received on an exterior portion of the driving member and having an interior surface spaced from an oppositely facing surface of the driving member to define a water chamber therebetween. The driving member is adapted to be drivingly engaged with the output shaft of a power transmission and to be secured to an end wall of a rotatable mixing drum having fluid passages provided therethrough. Fluid inlet means are provided to the annulus for supplying water to the water chamber and fluid passages through the driving member provide fluid communication between the water chamber and the fluid passages provided through the end wall of the mixing drum. In one embodiment of the invention, the annulus is provided with leg elements which define a recess therebetween, the water chamber is formed by the recess bounded by the leg elements and the exterior surface of the driving member, and sealing means are provided between the end surfaces of the leg elements and the driving member to permit relative movement therebetween.

Other objects, features and advantages of the invention will become apparent from the following description taken in conjunction with the accompanying drawings.

DESCRIPTION OF THE DRAWINGS

In the drawings, wherein like reference numerals refer to like parts:

FIG. 1 is a side elevational view of a transit or motor truck mounted concrete mixer incorporating one embodiment of the present invention;

FIG. 2 is a side elevational view mainly in section, showing the power transmission of FIG. 1.

Referring to the drawings and particularly to FIG. 1, a transit mixer is shown including a concrete mixing drum 10 which is rotatably mounted on the rear portion of a truck frame 11 of a conventional truck 12.

The truck includes a pair of front steering wheels 14 and tandem rear wheels 15 which are suspended from the frame 11 in any suitable conventional manner to allow movement of the truck 12. The frame 11 consists of a pair of laterally spaced longitudinally extending channel members which are interconnected to form a rigid and firm understructure for supporting the various operating members of the truck and the mixing drum. An internal combustion engine 21 is secured to the forward portion of the frame 11 and coupled to the rear wheels 15 by conventional means.

A cab 16 is secured to the forward portion of the frame 11 and encloses the engine 21 as well as steering, riding and other components of the truck 12.

The truck 12 is generally representative of vehicles presently constructed to carry a mixing drum partly filled with concrete, not shown, for transportation to a construction site.

The mixing drum 10 is shown as generally employed in the form of an elongated tapered cylinder. The back end of the drum 10 is formed with an opening 18 through which concrete may be selectively admitted and discharged. A hopper 19 is mounted above the opening 18 to direct concrete into the drum 10 and a discharge chute 20 is pivotally mounted immediately below opening 18 to direct discharging concrete to the desired location.

The mixing drum 10 is rotatably supported upon the back portion of the frame 11 by a forward drive and bearing unit 22 and a rear bearing unit 24. The rear bearing unit 24 is supported by pedestals 25 comprised of suitably formed structural steel members welded to the frame 11 and supported by cross-braces 26. The forward drive and bearing unit 22 is supported by pedestals 28 comprised of suitably formed structural steel members welded to the frame between the mixing drum 10 and the cab 16. A water tank 30 is mounted above and slightly to the rear of the cab 16 by means of an upper extension 29 of the pedestal 28. A pair of hoses 31 are connected to the tank for supplying water to the mixing drum 10 in a manner to be described more fully herebelow.

The forward drive and bearing unit 22 includes a power transmission 32 coupled to the forward end wall 17 of mixing drum 10 by a driving member 116. The power transmission 32 is provided in the form of an enclosed speed reducing gear train driven by a hydraulic motor 34. A pump 35 mounted to the truck 12 forward of the engine 21 provides a source of pressurized hydraulic fluid for the motor 34. The pump 35 is driven by means of a belt connection to the crankshaft of engine 21. Hydraulic fluid is delivered from the pump 35 to motor 34 by means of a supply conduit 36. The fluid is discharged from the motor 34 through a conduit 38 connected to a hydraulic fluid reservoir, not shown.

The forward drive and bearing unit 22 is shown in FIG. 2. The power transmission 32 and the coupling assembly for rotatably driving and supplying water to the mixing drum 10 will now be described in detail with reference to FIG. 2.

The power transmission 32 includes a planetary gear reducing train contained with a stationary housing comprising a main housing casting 40. The opposite sides of the main housing casting 40 are substantially closed by end plates 41 and 42 respectively secured to the housing 40 by means of a plurality of bolts 44 and 45. A relatively massive projection 46 is formed integrally with end plate 42 and is provided with an external spherical bearing surface 48 concentric with a bore 49. The spherical surface 48 is secured between oppositely facing complimentary curved surfaces provided to the pedestal 28 and pedestal extension 29 to provide the main bearing support for the forward drive and bearing unit 22. During assembly, the projection 46 is positioned on the pedestal 28 and the pedestal extension 29 is then positioned around the projection 46 and secured to the pedestal 28 by means of nut and bolt assemblies passing through aligned holes in flanges respectively provided to the pedestal 28 and pedestal extension 29. Additional support is provided by means of relatively massive lugs which are not shown in FIG. 2, but are formed integrally with the depending power input portion 50 of main housing casting 40 on opposite sides of the power input hydraulic motor 34. The lugs are provided with bores passing the bolt shanks of nut and bolt assemblies 23 which secure the power transmission 32 to support plates 27 welded to the truck frame 11, see FIG. 1.

The input to the power transmission 32 may be provided from either side of the depending portion of the transmission. In the drawings, a mounting flange formed integrally with the housing of hydraulic motor 34 is shown as being secured to the depending portion 51 of end plate 41 by a plurality of bolts 52. A cover plate 54 fixed by bolts 55 to the depending portion 50 of main housing casting 40 closes the alternate power input opening to power transmission 32.

The output drive shaft 56 of hydraulic motor 34 is drivingly engaged with an internal splined bore 58 of a hub 59 rotatably mounted at its opposite ends in ball bearing assemblies 60 and 61 disposed in opposed openings 62 and 64 respectively provided to the depending portions 50 and 51 of the main housing casting 40 and end plate 41. Gear teeth 65 formed integrally with and on the exterior surface of hub 59 mesh with the teeth of a spur gear 66 which is splined at 68 to a shaft 69.

Shaft 69 is rotatably mounted between housing castings 40 and end plate 41 in tapered roller bearing assemblies 70 and 71. The outer race of bearing assembly 70 axially abuts a shoulder provided internally of the housing casting 40 and the internal race abuts a shoulder provided to the shaft 69. The inner race of bearing assembly 71 abuts a shoulder provided to the opposite end of shaft 69 and the outer race axially abuts an internal surface 72 of a cap or cover plate 74 secured in place by bolts 75 to close an access opening through end plate 41.

A spur gear 76 having geared teeth 77 is integrally formed on shaft 69 adjacent the bearing assembly 70. Spur gear 76 meshes with spur gear 78 which is splined at 80 to a shaft 81. Shaft 81 is rotatably mounted at its opposite ends in tapered roller bearing assemblies 82 and 84. The inner and outer races of bearing assembly 82 are positioned in axial abutment with shoulders 85 and 86 respectively provided to shaft 81 and the power output shaft 110. Bearing assembly 84 is disposed in an access opening 88 provided through end wall 41, which opening is normally closed by a cap or cover plate 89 secured in place by bolts 90. A spacer ring 91 axially abuts a shoulder 92 provided to shaft 81 and prevents axial movement of a spur gear 78 along the shaft in the direction of end plate 41.

A sun gear 94 having teeth 95 is formed integral with the shaft 81 adjacent the bearing assembly 82. The sun gear 94 engages a set of three planetary pinion gears 96, only one of which is shown, which in turn engage a fixed internal ring gear 98. The ring gear 98 is positioned between an internal shoulder provided to the main housing casting 40 and the end plate 42 and is fixed against rotation by lugs 99 formed integrally with the end plate 42. The three planetary pinion gears 96 are carried by a freely rotating pinion cage 100 and journalled on pins 101, with each journal pin 101 being mounted on needle bearings 102 and containing lubricating passages 104. The passages 104 serve to lubricate the needle bearings 102 and the bearings rotatably supporting the output shaft 110. The end of the pinion cage 100 adjacent to the spur gear 78 is journalled for free rotation about shaft 81 by means of a centrally apertured plate 105. The opposite end of the pinion cage 100 is provided with an inwardly facing ring gear 106 having teeth 108 which drivingly engage the teeth of a spur gear 109 formed integrally with a shaft 110 at the inner end thereof.

The shaft 110 is the output drive shaft of the power transmission 32 and extends axially outward through the bore 49 of end plate projection 46 where it is internally rotatably mounted in tapered roller bearing assemblies 111 and 112.

The output shaft 110 extends axially outward beyond the axial end surface 114 of end plate projection 46 and is drivingly engaged with an internal splined bore 115 of the drum driving member 116. A hub plate 118 secured to the end of output shaft 110 by bolts 119 prevents axially outward movement of the drum driving member 116. The inner end of the hub 120 of drum driving member 116 axially abuts the inner race of bearing assembly 111 and seats the outer race against a shoulder provided internally of the end plate projection 46. The outer race of bearing assembly 112 is seated against an oppositely disposed shoulder provided internally of end plate projection 46 and the internal race axially abuts a radial surface of spur gear 109.

The drum driving member 116 includes a radially extending flange 121 and a drum end wall abutting surface 122 on one axial side thereof. The drum end wall 17 is shown by phantom lines in FIG. 2 with the surface 122 abutting thereagainst and flange 121 drivingly secured to the end wall 17 by means of bolt and nut assemblies 124 passing through aligned holes respectively provided through the flange 121 and end wall 17. On the side of the drum driving member 116 axially opposite to the end wall abutting surface 122 the exterior of the hub 120 is stepped to provide first and second cylindrical services 125 and 126.

A metal annulus 128 having a continuous internal recess 129 is slidably received on the exterior surface of the hub 120. The recess 129 is provided between a pair of leg elements 130 and 131 having inwardly facing cylindrical surfaces 132 and 134 proximate the ends of leg elements 130 and 131, respectively. The surfaces 132 and 134 of leg elements 130 and 131 are slidably received on axially spaced portions of the concentric surfaces 125 and 126 respectively. The annulus is provided with a pair of internally threaded inlet passages 135, only one of which is shown. The threaded inlet passages 135 receive male couplings provided on the ends of water supply hoses 31 and thereby supply water from the tank 30 to the recess 129. The recess 129 is bounded by the exterior surface of hub 120 and thereby provides a water chamber for supplying water to the interior of mixing drum 10. A pair of circumferentially extending grooves 136 are provided to the cylindrical surface 125 and a pair of O-rings are disposed in the grooves 136 to provide a fluid seal between the cylindrical surface 125 and annulus surface 132. A similar pair of circumferentially extending grooves 138 are provided by cylindrical surface 126 and a pair of O-rings are disposed in grooves 138 to provide a fluid seal between the cylindrical surface 126 and end surface 134 of leg element 131.

Although the O-rings disposed in grooves 136 and 138 provide an effective fluid seal between the oppositely disposed surfaces of the annulus 128 and hub 120, the annulus 128 remains free to move relative to the hub 120. Thus when the water supply hoses 31 are connected to the hose couplings 135 the drum driving member 116 may rotate freely while the annulus 128 is held against rotation on the hub 120 by the water supply hoses 31. The annulus 128 is also free to move axially a slight distance along the stepped hub 120. Axial movement of the metal annulus 128 toward the drum end wall 17 is limited by abutment of the annulus 128 with the shoulder extending radially outward from the cylindrical surface 125. Axial movement of the annulus 128 in the opposite direction is limited by abutment of the annulus 128 with the axial end surface 114 of projection 46 of end plate 42.

The mixing drum driving member 116 is provided with a plurality of circumferentially spaced holes or water passages 139 having ports 140 at one end which open through a radial exterior surface of the stepped hub 120 between the cylindrical surfaces 125 and 126. The water passages 139 open at their opposite ends into an annular recess 141 provided to the drum end wall abutting surface 122 radially inward of the flange 121. The annular recess 141 is located opposite a plurality of circumferentially spaced holes or water passages 142 shown by dotted line through the mixing drum end wall 17. The end wall abutting surface 122 radially outward of the annular recess 141 is provided with a annular groove 144. An O-ring disposed in the annular groove 144 is axially compressed between the mixing drum driving member 116 and the end wall 17 of the mixing drum 10 to provide a fluid seal therebetween.

The apparatus and coupling assemblies as hereinabove described thus provides an effective means for rotatably driving a concrete mixing drum and supplying water thereto. The drum driving member 116 is drivingly engaged with the output shaft 110 of the power transmission 32 and is secured by means of its radially extending flange 121 and bolt and nut assemblies 124 to the end wall 17 of mixing drum 10 to effect rotation of the mixing drum 10 upon actuation of the hydraulic motor 34. Water may be supplied from the tank 30 and supply hoses 31 to the mixing drum 10, whether the drum is rotating or stationary, via the water supply chamber provided by the recess 129 of annulus 128, the water passages 139 and 141 through drum driving member 116, and the water passages 142 through the end wall 17 of mixing drum 10. Although any suitable number of water supply passages 139 may be provided through the drum driving member 116, six 7/8-inch diameter holes have provided an adequate flow rate through the drum driving member 116 with an equal number of the same size water passages provided through the end wall 17 of mixing drum 10.

It is to be understood that the above detailed description of the present invention is intended to be disclosed a specific embodiment thereof to those skilled in the art, but that the invention is not to be construed as limited its application to the details of construction and the arrangement of parts illustrated in the accompanying drawings, since the invention is capable of being practical and carried out in various ways without departing from the spirit of the invention. The language used in the specification to describe the elements of the invention and the function of those elements is primarily employed for purposes of description and it is not intended to limit the scope of the following claims beyond the requirements of the prior art.