Patent Application
20080128193
The present invention is related to the field of fluid drive systems, in particular, fluid drive systems used to transfer power from a tractor power take-off (“PTO”) to a vertical mixing tub for mixing feedstuffs for livestock.
Vertical feed mixers have been used in agriculture for many years. Vertical mixers process forages and commodities of all types of feed for livestock. Vertical mixers include a tub containing one or more vertical augers. These augers can have knives mounted on their flights such that when the augers rotate, the knives will cut the forage and the augers will process and blend the components within the tub. The augers are typically driven using power from the PTO of a tractor or other type of motor vehicle having a suitable PTO system. Known designs of vertical mixers use automatic transmissions or 2- or 3-speed manual gearboxes in the driveline between the PTO and the augers in the vertical mixer.
The use of such transmissions or gearboxes is prone to failures due to the high start-up torque required to engage large mixers. In order to reduce the cost of the mixer, gearboxes are used that are not rated for the amount of horsepower and duty cycles that large mixers require. The operator of the mixer is required to shift gears on the gearbox while on the tractor seat using a shift cable. To do so requires that the PTO be disengaged and all driveline movement stopped so that gears can be shifted. On larger mixers, this process often adds too much time to feeding schedules for most operators. Operator misuse of the system often leads to component failures. The use of automatic transmissions solves the manual gearbox shifting problems but most suffer from mounting, cooling and reliability issues. Repairs to automatic transmissions are expensive.
A fluid drive system is provided for a vertical mixer tub having one or more augers. In one embodiment, the system comprises an input gearbox for increasing the rotational speed of an input shaft driven by a PTO mounted on a vehicle such as a tractor or truck. In another embodiment, the gear ratio of the input gearbox can be 1:2 to provide an output rotational speed double that of the input shaft. A coupling shaft is used to connect the output of the input gearbox to a soft start fluid coupler or torque converter. In one embodiment, a flex coupling can be mounted between the coupling shaft and the input of the fluid coupler to reduce the shock and stress on the driveline system due to the high torque requirements on starting a mixer tub loaded with feed. A coupling shaft connects the output of the fluid coupler to an output gearbox that reduces the rotational speed of the coupling shaft. In one embodiment, the gear ratio of the output gearbox can be 2:1 to provide an output rotational speed half of the fluid coupler output. The output of the output gearbox is then connected to a drive shaft that is coupled to a drive mechanism of the auger in the vertical mixing tub, as well known to those skilled in the art.
In operation, the rotational speed of the PTO-driven input shaft can typically reach up to 1000 revolutions per minute (“RPM”). The input gearbox increases this input speed up to 2000 RPM whereby the fluid coupler can easily “lock-up” once the PTO speeds up to its nominal 1000 RPM speed. The output gearbox reduces the output speed of the fluid coupler back to 1000 RPM, which is a speed that is better suited for driving the auger in the vertical mixer tub.
A fluid drive system for a vertical mixer tub is provided. Referring to
Fluid drive system 20 includes input drive shaft 11 coupled to spline shaft 12 of input gearbox 1. Input drive shaft 11 is driven by a PTO (not shown) that can be powered by a motor vehicle such as a tractor, a truck or any other suitable vehicle or machinery as well known to those skilled in the art. Gearbox 1 is a gear increasing transmission. In a representative embodiment, gearbox 1 has a gear ratio of 1:2 to provide an output rotational speed twice that of the input rotational speed.
Coupling shaft 5 connects the output of gearbox 1 to the input of fluid coupler 3. In another embodiment, a flex coupler can be placed between the input of fluid coupler 3 and coupling shaft 5 to absorb driveline vibrations or stress when fluid drive system 20 is in operation. In a representative embodiment, fluid coupler 3 can be a hydrokinetic transmission or torque converter as well known to those skilled in the art.
The output of fluid coupler 3 is connected to the input of gearbox 2 via coupling shaft 6. In one embodiment, gearbox 2 is a gear reducing transmission. In a representative embodiment, gearbox 2 has a 2:1 gear ratio to provide an output rotational speed one-half of the input rotational speed. The output of gearbox 2 is connected to drive shaft 14 that, in turn, is connected to the drive mechanism of an auger in a vertical mixing tub (not shown) as well known to those skilled in the art.
In one embodiment, gearboxes 1 and 2 are attached to and supported by side mounting plates 8 with bolts 18. Fluid coupler 3 is positioned in and supported by side mounting plates 8 in recesses 16. Side mounting plates 8 can be mounted on any suitable mounting surface that is in proximity to drive shaft 11 and PTO as well as the vertical mixing tub. In this configuration, side mounting plates 8 provide structural support for gearboxes 1 and 2 and fluid coupler 3.
In another embodiment, cover shield 9 is attached to side mounting plates 8 to provide a protective shield over gearboxes 1 and 2 and fluid coupler 3. In a representative embodiment, fluid drive system 20 can be mounted on the frame or structure that supports the vertical mixing tub it operates. For example, mounting flanges 22 can be fastened to a frame or mounting platform disposed on a mixing tub or on a frame or mounting disposed on a vehicle by using bolts 24 and nuts 26. In a further embodiment, shield cover 10 is attached to side mounting plates 8 to provide a protective shield over drive shaft 11 where it couples with gearbox 1.
In operation, an operator throttles up the vehicle that powers the PTO in order to begin rotating drive shaft 11. In a representative embodiment, the PTO will turn drive shaft 11 up to approximately 1000 RPM. As drive shaft 11 begins to turn and speed up its rotational speed at the input of gearbox 1, gearbox 1 turns coupling shaft 5 at a rotational speed faster than drive shaft 11. In the illustrated embodiment, gearbox 1 causes coupling shaft 5 to turn at twice the speed of drive shaft 11. Coupling shaft 5 turns the input of fluid coupler at a speed greater than 1000 RPM so that fluid coupler 3 can work near its peak efficiency. During start-up of the PTO, there is slippage initially within fluid coupler 3 that allows fluid coupler 3 to absorb vibrations in the driveline of the system during the start-up procedure.
As the PTO throttles up to its nominal operational speed of 1000 RPM, coupling shaft 5 will turn at approximately 2000 RPM, which is a sufficient input rotational speed to fluid coupler 3 to “lock it up” and turn coupling shaft 6 at approximately 2000 RPM as well. Gearbox 2 reduces the input rotational speed of coupling shaft 6 to approximately 1000 RPM at the output of gearbox 2. Drive shaft 14, being coupled to the output of gearbox 2, will also turn at approximately 1000 RPM which is a suitable rotational speed to drive an auger in a vertical mixing tub as well known to those skilled in the art.
A fluid drive system can accordingly be provided in a driveline between a PTO and a vertical mixer and, while simple and reliable, can handle the large start-up torque requirements when the mixer is loaded with foodstuffs to be mixed and/or cut.
Although a few embodiments have been shown and described, it will be appreciated by those skilled in the art that various changes and modifications might be made without departing from the scope of the invention. The terms and expressions used in the preceding specification have been used herein as terms of description and not of limitation, and there is no intention in the use of such terms and expressions of excluding equivalents of the features shown and described or portions thereof, it being recognized that the scope of the invention is defined and limited only by the claims that follow.
| Number | Date | Country | Kind |
|---|---|---|---|
| 2,569,441 | Nov 2006 | CA | national |
The present application claims priority of U.S. Provisional Application Ser. No. 60/870,340 filed Dec. 15, 2006 and hereby incorporates the same Provisional Application by reference. The present application also claims priority of Canadian Patent Application Serial No. 2,569,441 filed Nov. 30, 2006 and hereby incorporates the same Canadian Patent Application by reference.
| Number | Date | Country | |
|---|---|---|---|
| 60870340 | Dec 2006 | US |
