GB2029314A - Baler auxiliary drives - Google Patents

Abstract

In an agricultural pickup baler, the twine-tying or wire-twisting mechanism is driven by a shaft whose input end meshes directly with a gear carried on the end of the shaft which drives the ram crank arm, and whose output end meshes directly with the rotating twine-tying or wire-twisting mechanism itself. Said mechanism is thus drivingly connected to the ram crank arm through only two pairs of meshing gears. Said gear carried by the output shaft is itself located on the outside of the main gearbox housing. <IMAGE>

Description

SPECIFICATION Baler auxiliary drives The invention relates to baler auxiliary drives, and is applicable specifically to the kind of agricultural baler which is intended to be towed behind a tractor to bale stem materials and is known generally as a pickup baler.

In such balers, the main gear box is traditionally situated at the front part of the baler chassis and is driven by an input shaft on the baler, the input shaft in turn being powered through a suitable universal joint by the power takeoff drive of the tractor. The output from the main baler gearbox is taken from a shaft which projects generally at right-angles to the baler gearbox input shaft, and since this input shaft runs traditionally along the baler then the baler gearbox output shaft projects generally at right-angles to the normal direction of longitudinal travel of the baler.

It is conventional to mount on one projecting end of the baler gearbox output shaft a crank arm which drives the ram of the baler unit. It is clearly important to synchronise the various auxiliary mechanisms -- such as the pickup unit, the packing mechanism, the conveyor and the bale twine tying unit -- accurately with the repeated operations of the ram. It is also recognised as inevitable that, with repeated use, a certain back lash will develop in whatever drives are employed to transmit the baler gearbox output to these various auxiliary mechanisms.

In its broadest aspect, the invention provides a pickupbaler of the kind broadly outlined above, characterised by the following features: (a) The output drive from the main baler gearbox is transmitted initially through a crown wheel which is situated at the opposite end of the main output shaft to the ram crank arm; (b) The main output shaft projects at both ends from the main baler gearbox housing, and so said crown wheel is outside the gearbox housing; and (c) The various auxiliary drive mechanisms powered from the main baler gearbox, at least the twine tying mechanism is driven by a shaft whose input end meshes directly with said crown wheel and whose output end meshes directly with the rotating twine tying mechanism, so that said mechanism is drivingly connected to the main baler gearbox output shaft through only two pairs of meshing gears.

With such an arrangement, the twine tying mechanism is synchronised with the ram operations through a drive which minimises the risk of any excessive backlash developing in use.

It is especially important to synchronise the twine tying mechanism with the operations of the ram, since this mechanism is more susceptible than the remaining auxiliary mechanisms to any inaccuracies in such synchronisation. The invention lends itself also to the use of a simple direct drive generally along the baler, and out of the way of the ram, the packing chamber and the pickup unit since simple angled crown wheel and pinion drives can be used at either end of the auxiliary drive shaft and the main power transmitting crown wheel is already on the opposite side of the gearbox housing from the ram crank arm.

The or each other auxiliary drive shaft, at least insofar as it extends along the baler, can also be driven by direct meshing engagement with the main power transmltting crown wheel provided on the main gearbox output shaft. The invention thus makes it possible to dispense entirely with any auxiliary drive gears, and to minimise the areas in which backlash can develop as the drive mechanisms inevitably wear during use.

Any or all of these auxiliary drives may be accomplished by using bevel gears for the various crown wheel and pinion drives, since these have a noticeably larger area of flank contact between their meshing teeth than other drives and are consequently less likely to be seriously affected by wear.

It is thus possible for all the auxiliary drives, including the pickup drives (which is traditionally not driven by gearing) to be directly driven from the output of the main baler gearbox via a series of auxiliary drive shafts and angled gear drives.

The accompanying drawings show, by way of example only, the diagrammatic layout of the drives in one pickup baler embodying the invention.

The power takeoff drive from the tractor (not shown) is coupled to a multiple-jointed baler gearbox input shaft (not shown) which runs generally along the baler and parallel with the normal intended longitudinal direction of travel of the baler. This input shaft is supported in conventional manner on a boom which projects forwardly from the front of the baler.

The input shaft enters the main baler gearbox, and its drive is transmitted through a right-angle via a crown wheel and pinion to the baler gearbox output shaft, This shaft is carried in conventional thrust absorbing tapered roller bearings in the main gearbox housing, and it projects from each end of that housing. The housing is so located that the baler gearbox output shaft projects generally across and at right-angles to the normal intended longitudinal direction of travel of the baler.

A crank arm (not shown) is secured to that end of the baler gearbox output shaft which projects towards the centre of the baler. A relatively large diameter crown wheel is secured to the other end of the baler gearbox output shaft, and so is outside the gearbox housing. In this particular example, the crown wheel is a bevel wheel.

Meshing with this bevel wheel is a much smaller bevel pinion, which is attached rigidly to one end of a hexagonal section rigid drive shaft.

The drive shaft runs generally along the baler, but on the other side of the bale packing chamber to the pickup unit and the ram, and another bevel pinion is secured to its far end. This other bevel pinion meshes directly with a bevel crown wheel, and the bevel crown wheel is secured to a shaft which rotates directly the bale twine tying or wire twisting mechanism (not shown).

The twine tying mechanism is thus driven from the main gearbox output shaft through only two pairs of meshing gears interconnected by a rigid drive shaft. This minimises the risk of the twine tying mechanism falling badly out of synchronisation with the ram drive as the drive mechanisms inevitably wear after prolonged use of the baler.

As shown in the drawings the same basic principle can be used to drive the remaining auxiliary mechanisms on the baler. Approximately halfway along the hexagonal section drive shaft, another bevel pinion is rigidly secured. This meshes with a further pinion, which rotates another rigid drive shaft, at the far end of which another pair of meshing bevel pinions transfers the drive to the packing mechanism.

Similarly, although this is not illustrated in the drawings, a bevel pinion meshing with the main crown wheel on the gearbox output shaft could rotate a drive shaft which, via another pair of angled bevel gears directly drives the pickup unit Some of the drive shafts used on a baler embodying the invention may be fairly long, since they run virtually the whole length of the baler. To make assembly and/or servicing easier, the drive shafts could be universally jointed at one of more points along their length, so that each drive consisted in practice of a number of directly jointed linked short drive shafts. This principle could be used for example to link the twine tying mechanism to the main gearbox output by a drive Tine which was approximately horizontal along the greater part of its length, deviating from the horizontal (by means of the aforesaid universal joints) only at the end at which it meshes with the main output bevel wheel on one end of the gearbox output shaft.

Claims (4)

1. An agricultural pickup baler in which a main gearbox is situated towards the front end of the baler and is adapted to receive a power input from a tractor coupled, in use, to that front end, in which an output shaft of said gearbox runs generally across the baler (relative to the baler's normal intended direction of travel); in which the output shaft carries at one end a crank which drives the baling ram; and in which the output shaft carries at its other end a toothed wheel; characterised in that said other end of the gearbox output shaft projects from the gearbox, so that said toothed gear wheel is carried outside the gearbox housing, and further characterised in that the twine-tying (or wire-twisting) mechanism of the baler is driven by a shaft whose input end meshes directly with said toothed gear wheel and whose output end meshes directly with a rotating part of the twine-tying (or wire-twisting) mechanism.

2. A baler according to claim 1, characterised in that one or more futher auxiliary mechanisms of the baler is or are driven by a shaft which meshes directly with said toothed gear wheel.

3. A baler according to claim 2, in which each gearbox-driven auxiliary mechanism of the baler is drivingly linked to the ram crank arm, via said toothed gear wheel, through no more than two respective pairs of meshing gears.

4. An agricultural pickup baler substantially as described herein with reference to, and ab illustrated in, the accompanying drawing.