US 3756572 A
A truck mounted concrete mixer has a hydraulic drive through a gear reduction unit at the forward end of the mixing drum. A support column attached to the truck frame supports the gear reduction unit in a manner to minimize transmittal of truck frame deflections under operating condition to the gears in the gear reduction unit. Specifically, the front of the gear reduction unit is connected to the support column at a point in front of the drum support shaft while the rear of the gear reduction unit is rigidly connected to the support column on a line transverse to the axis of the drum and below the point of support of the forward end of the drum.
Description (OCR text may contain errors)
United States Patent 1 Buelow et al.
[451 Sept. 4, 1973 TRUCK MIXER FORWARD SUPPORT AND DRIVE MEANS  US. Cl 259/177 A  Int. Cl. B28c 5/18, B28c 5/26  Field of Search 259/177 R, 177 A,
 References Cited UNITED STATES PATENTS Oury 259/177 A Lendved 259/177 R 3,190,621 6/1965 Green 259/177 Primary Examiner-Robert W. Jenkins Attorney-Richard C. Sughrue et al.
[5 7] ABSTRACT A truck mounted concrete mixer has a hydraulic drive through a gear reduction unit at the forward end of the mixing drum. A support column attached to the truck frame supports the gear reduction unit in a manner to minimize transmittal of truck frame deflections under operating condition to the gears in the gear reduction unit. Specifically, the front of the gear reduction unit is connected to the support column at a point in front of the drum support shaft while the rear of the gear reduction unit is rigidly connected to the support column on a line transverse to the axis of the drum and below the point of support of the forward end of the drum.
8 Claims, 6 Drawing Figures PATENTEDSEP m 3.756572 SHEETIOF 2 BACKGROUND OF THE INVENTION 1. Field of the Invention This invention relates to improvements in truck mounted concrete mixers with support front and drive means for the mixer drum. More specifically, it relates to a unique mounting for the drive means which minimizes transmission of truck frame deflections to the drive gears.
2. Prior Art Concrete mixers are conventionally mounted on trucks for mixing concrete within a rotating mixer drum while the truck is moving as well as when the truck is stationary. It is known in the art to drive a truck mounted mixing drum from its lower forward end by gears or the like. Although trucks which mount concrete mixing drums are quite strong and have heavy duty frames; nevertheless, these frames flex and deflect in various planes and directions under load and in operation, for example when a loaded truck mixer passes over a bump. The flexing or movement of a truck frame which carries a gear drive for a rotating drum causes misalignment of the gears since the frame will flex or move relative to the drum it supports and the gear trains are supported at one end by the truck frame and at the other end connected to the drum. Misalignment of gears of course causes undue wear necessitating early maintenance or replacement.
SUMMARY OF THE INVENTION The problem of mounting a gear drive for the supported and driven end of truck mounted drum mixers so that the gears will not mis-align when the truck frame flexes is overcome by a unique mounting for a gear case housing the drive gears. The gear case is supported by a columnar support rigidly connected to the support at only two places. One connection is a point connection in front of the drum drive shaft and generally on a vertical axis passing through the drum and drive shaft axis of rotation. The other support is a line support extending transversely under the forward drum support. These two fixed connections are between a columnar support and the gear case. The gear case may be in two sections and the fixed connections are at the dividing line of the sections. The columnar support is attached at its lower ends to the channels of the truck frame. With this mounting the truck channels can deflect relative to one another without effecting alignment of the gears.
BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a side elevation view of a truck mounted drum mixer with forward support and drive for the 'mixer drum.
FIG. 2 is a detailed side elevation view with a portion.
broken away for clarity of a support and drive assembly of this invention.
FIG. 3 is a front elevation view of the support assembly of FIG. 2.
FIG. 4 is a top plan view taken along line 44 of FIG. 2.
FIG. 5 is a side elevation view similar to FIG. 2 showing the condition of the support assembly when one of the truck frame channels deflects.
FIG. 6 is a fragmentary detailed side sectional view illustrating the connection of the front of the gear case to the support column.
DESCRIPTION OF THE PREFERRED EMBODIMENT A truck 10 carries a mixer drum 12 behind the cab 14. The truck has wheels l6and a frame 18 as is common. The frame 18 includes side channels 20 and 22 as well as a cross brace 24. Although the truck frame is heavy duty, it is not absolutely rigid and passing over an uneven road with a load the frame will flex as is common.
The mixer drum 12 is supported with its forward end down by supports which include a rear support assembly 26 as is conventional, see US. Pat. No. 3,073,580 and a partially spherical front support 28, see FIG. 2.
The drive of the mixer drum 12 is from the forward end through a drum drive shaft 30. An engine driven hydraulic pump 32 is mounted in front of the cab 14 and furnishes hydraulic fluid under pressure through lines not shown to a hydraulic motor 34. A gear reduction unit 36 houses gears 38 of conventional type and includes an outer gear casing assembly 40. The gear casing assembly is made of two sections, an upper section 42 of ductile iron for strength and a lower section 44 of aluminum for light weight. The hydraulic motor 34 is attached to the lower section 44 for driving the drum 12 through drive shaft 30 and the gears 38 of the gear train.
The gear case assembly is supported solely on a support column 46. The support column may be of welded plate construction and is box shaped in section including a front 48, a back 50 and sides 52 and 54. At the top front of the support column 46 there is a welded channel 56 forming a ledge. A further ledge is provided across the inside of the top back of the support column 46 by a welded angle 58. The lower margins of sides 52 and 54 are rigidly secured respectively to the beams 58 and 59 by bolts 61 or equivalent fastening means. Beams 58 and 59 connect column 46 and rear assembly 26 and rest on channels 20 and 22 of the truck frame 18. Means, not shown, secure beams 58 and 59 to the respective channels.
The two sole connections between the gear case assembly 40 and the support column 46 are first, a single central connection at the forward end and transverse center of the gear casing 40 accomplished by rigidly bolting the gear casing 40 to ledge 56 by bolts 64. As can be seen, the bolts 64 are generally adjacent the center or longitudinal axis of the vehicle and drum. In other words, the point support accomplished by bolting the gear casing 40 to the ledge 56 by bolts 64 is generally in a vertical plane passing through the axis rotation of the drum 12 and drive shaft 30.
The other fixed connection of the gear case assembly 40 to the support column 46 is a line connection extending along the rearward edge of the gear casing. Thisis accomplished by bolting the casing to channel 58 by bolts 62. The bolts 62 can extend completely across the rear edge or, in case the area under the drive shaft 30 is inaccessible, can be attached at the outer edges to accomplish the same rigid connection. This rigid connection extends completely across a line extending transversely across the vehicle and transverse to the axis of rotation of the shaft and drum and generally below the spherical support 28 for the drum.
As shown, the upper and lower gear case sections 42 and 44 are provided with the adjoining circumferential, projecting flanges 72 and 74, respectively. The bolts 62 extend through the flanges where they rest on the ledge provided by angle 58 on one side of the gear case. The bolts 64 extend through the flanges where they extend as at 76 beneath shaft 30 on the other side of the gear case. The bolts 64 secure the flanges to the ledge provided by channel 56.
In the operation of the truck mixer over uneven ground the channels 20 and 22 can and do deflect relative to each other and even move longitudinally relative to each other. Deflection of channel 20 is shown in FIG. causing deflection of side 54 of support column 46. However, because of the mounting of gear case assembly 40, none of the truck frame deflection is transmitted to the gear case and hence to the gears therein.
What is claimed is:
1. In a concrete mixer for mounting on a truck frame, said mixer having a drum for receiving, mixing and discharging concrete and journal bearings supporting one end thereof; means for supporting and driving the other end of said drum and comprising a support column having its lower end adapted to be secured to the truck frame and upper support and securement surfaces, a gear reduction unit having an output shaft coupled to the other end of said drum, said gear reduction unit resting on and secured to the support and securement surfaces of said support column, one of said securement surfaces being substantially directly beneath said output shaft on one side of the gear reduction unit and the other of said securement surfaces being on the other side of the gear reduction unit and in a generally vertical plane extending through the output shaft.
2. The support and drive means of claim 1 wherein the support column is of welded metal plate construction and has laterally spaced sides adapted to rest on and to be secured to the two longitudinal frame members of a conventional truck and having a rectangular upper section which surrounds the lower part of a gear case of the gear reduction unit.
3. The support and drive means of claim 2 wherein the gear reduction unit includes a gear case comprising joined upper and lower sections, the upper section including said brackets and the lower section depending therefrom and within the support column.
4. The support and drive means of claim 3 wherein the lower section includes mounting means for the direct attachment and support of a drive motor.
5. In a rotary drum concrete mixer mounted on a truck including gear means for driving the closed end of the drum, the improvements in mounting and supporting the gear means to minimize transmission of truck frame movement to the gears thereof, comprising a drum support for the closed end of the rotary drum, a gear case housing and supporting the gear means for driving the drum, an upright columnar support with its lower end attached to the truck, a first rigid connection between the upper end of the columnar support and the gear case extending transverse to an axis of rotation of the drum and positioned on one side of the gear case and below the drum support for the closed end of the drum, a second rigid connection between the upper end of the columnar support and the gear case in a vertical plane containing the axis of rotation of the drum and on the other side of the gear case respecting the first rigid connection, the first and second rigid connections constituting the only connections between the gear case and the columnar support.
6. A rotary drum concrete mixer mounted on a truck as in claim 5 further comprising a hydraulic motor for driving the gear means, the hydraulic motor carried by the gear case.
7. A rotary drum concrete mixer mounted on a truck as in claim 6 wherein the gear case is divided horizontally into two sections, a strong upper section and a lightweight lower section, and the fixed connections of the gear case to the columnar support are at the division between the sections, and the hydraulic motor is carried by the lower section.
8. A rotary drum concrete mixer mounted on a truck as in claim 7 wherein the columnar support is a hollow box section column.
. UNnEn STATES PATENT OEFECE QERTEFECATE OF CORRECTIGN P t t; N Dated September 4, 1973 William H. Buelow et al I Inventor(s) It is certified that error appears in the above-identified patent and that said Letters Patent are hereby corrected as shown below:
In the Heading:
The name of the Assignee should read:
-- Assignee: Rexnord Inc.
Signed and sealed this 15th day of January 19714..
( SEAL) Attest EDWARD. M. FLETCHER, JR. RENE D. TEGTMEYER.
Attesting Officer Act ing Commissioner of Patents FORM P0- 050 (10- USCOMM-DC 60376-P69 I fi' U.S. GOVERNMENT PRINTING OFFICE I969 0-356-334,