GB1562565A - Power take-off means for vehicles - Google Patents

Description

(54) IMPROVEMENTS IN OR RELATING TO POWER TAKE-OFF MEANS FOR VEHICLES (71) We, UNI-DRIVE TRACTORS LIMITED, a British Company, of Alpha Works, Station Road, Ampthil, Bedfordshire, do hereby declare the invention, for which we pray that a patent may be granted to us, and the method by which it is to be performed, to be particularly described in and by the following statement: This invention relates to vehicles equipped with power take-off drive units, hereinafter referred to as PTO drive units, particularly agricultural vehicles such as tractors.

Known tractors have a power take-off at their rear ends which is used to drive implements detachably secured to, and towed by, the tractor. Such power, take-off usually comprises a transmission linkage, such as a drive shaft, connected to and driven by the tractor engine.

It is an object of the present invention to provide a PTO drive unit at the front of a vehicle, such as a tractor, which can be used to drive implements detachably secured to, and pushed by, the vehicle. It is particularly useful for driving implements detachably secured to the front end of a tractor by means of a three-point linkage, for example a three-point linkage as described in our co-pending U.K. patent application No.

13303/75. Serial No. 15 47 560.

In accordance with the present invention there is provided a vehicle equipped with a power take-off drive unit at the front end of the vehicle, wherein the vehicle crankshaft is provided with a crankshaft pulley, a resilient coupling is bolted on to the front of the pulley, a drive shaft extends forwardly from the coupling with the coupling providing a capacity for flexing movement of the drive shaft, and the drive shaft is connected to a forwardly projecting power take-off shaft by way of a clutch and a reduction gearbox.

The clutch is preferably a hydraulic multi-plate clutch. Preferably, the clutch is positioned between the crankshaft extension and the reduction gearbox and the power take-off shaft is at the output side of the reduction gearbox.

A number of embodiments in accordance with the invention will now be described by way of example and with reference to the accompanying drawings, in which: Fig. 1 is a schematic view of a first embodiment of vehicle with drive unit in accordance with the invention; Fig. 2 is a view of a second embodiment of vehicle and drive unit; and, Fig. 3 is a schematic view of a third embodiment of vehicle and drive unit.

Referring first to Fig. 1, this shows part of the front of a tractor engine compartment wherein the crankshaft is indicated at 10.

The crankshaft 10 carries gearing 12 and has a forwardly projecting portion 14 which terminates in a crankshaft pulley 15. A drive shaft 16 is coupled to the crankshaft via the pulley 15 by a suitable coupling 18 which is bolted directly on to the front of the pulley 15 and which provides a certain degree of resilience and thus a capacity for flexing movement of the shaft 16. The drive shaft 16 is connected to a reduction gearbox 20 which has an outward shaft 22 leading to a clutch indicated generally at 24. A power take-off splined shaft 26 is provided at the output side of the clutch 24.

The clutch 24 is preferably a hydraulic multi-plate clutch, the hydraulic connection being indicated for example at 28 in Fig. 3.

It is conventional for tractor crankshafts to rotate at 1800 rpm, and the reduction gearbox 20 is preferably such that the splined output shaft 26 is driven at a speed of between 540 and 1000 rpm. However, these speeds are only given as an indication of typical values.

In the embodiments shown in Figs. 2 and 3 elements which are the same as or equivalent to those shown in Fig. 1 are indicated by the same reference numerals. In Fig. 2, the drive from the crankshaft extension 14 through the pulley 15 and the resilient coupling is taken indirectly by way of chain gearing 30 to the clutch 24, and thence via the reduction gearbox 20 to the output shaft 26. This indirect drive may be necessary for certain types of vehicle where space limitation within or in front of the engine compartment make it impossible to adopt the arrangement shown in Fig. 1 for example.

The alternative arrangement shown in Fig. 3 has a direct drive from the crankshaft extension 14 to the clutch 24 by way of the pulley and resilient coupling and the transmission shaft 16. The reduction gearbox 20 is again provided at the output side of the clutch 24 and provides its output to the splined shaft 26.

WHAT WE CLAIM IS: 1. A vehicle equipped with a power take-off drive unit at the front end of the vehicle, wherein the vehicle crankshaft is provided with a crankshaft pulley, a resilient coupling is bolted on to the front of the pulley, a drive shaft extends forwardly from the coupling with the coupling providing a capacity for flexing movement of the drive shaft, and the drive shaft is connected to a forwardly projecting power take-off shaft by way of a clutch and a reduction gearbox.

2. A vehicle as claimed in claim 1, in which said clutch is a hydraulic multi-plate clutch.

3. A vehicle as claimed in claim 1 or 2, in which said clutch is positioned between the crankshaft extension and the reduction gearbox and the power take-off shaft is at the output side of the reduction gearbox.

4. A vehicle as claimed in claim 3, in which the drive from the crankshaft pulley to the clutch is an indirect drive.

5. A vehicle as claimed in any preceding claim, in which the reduction gearbox provides an output at between 540 to 1000 r.p.m.

6. A vehicle equipped with a power take-off drive unit at the front end of the vehicle substantially as hereinbefore described with reference to Fig. 1, Fig. 2 or Fig. 3 of the accompanying drawings.

**WARNING** end of DESC field may overlap start of CLMS **.

Claims (6)

**WARNING** start of CLMS field may overlap end of DESC **. by the same reference numerals. In Fig. 2, the drive from the crankshaft extension 14 through the pulley 15 and the resilient coupling is taken indirectly by way of chain gearing 30 to the clutch 24, and thence via the reduction gearbox 20 to the output shaft 26. This indirect drive may be necessary for certain types of vehicle where space limitation within or in front of the engine compartment make it impossible to adopt the arrangement shown in Fig. 1 for example. The alternative arrangement shown in Fig. 3 has a direct drive from the crankshaft extension 14 to the clutch 24 by way of the pulley and resilient coupling and the transmission shaft 16. The reduction gearbox 20 is again provided at the output side of the clutch 24 and provides its output to the splined shaft 26. WHAT WE CLAIM IS:

1. A vehicle equipped with a power take-off drive unit at the front end of the vehicle, wherein the vehicle crankshaft is provided with a crankshaft pulley, a resilient coupling is bolted on to the front of the pulley, a drive shaft extends forwardly from the coupling with the coupling providing a capacity for flexing movement of the drive shaft, and the drive shaft is connected to a forwardly projecting power take-off shaft by way of a clutch and a reduction gearbox.

2. A vehicle as claimed in claim 1, in which said clutch is a hydraulic multi-plate clutch.

3. A vehicle as claimed in claim 1 or 2, in which said clutch is positioned between the crankshaft extension and the reduction gearbox and the power take-off shaft is at the output side of the reduction gearbox.

4. A vehicle as claimed in claim 3, in which the drive from the crankshaft pulley to the clutch is an indirect drive.

5. A vehicle as claimed in any preceding claim, in which the reduction gearbox provides an output at between 540 to 1000 r.p.m.

6. A vehicle equipped with a power take-off drive unit at the front end of the vehicle substantially as hereinbefore described with reference to Fig. 1, Fig. 2 or Fig. 3 of the accompanying drawings.