Crop hold down arrangement for pick-up

A crop hold down arrangement for a pick-up comprises a roll supported by means of pivot arms from the frame so as to enable the arms to pivot vertically and guide the roll in the direction of crop being fed by a tined pick-up drum to a conveyor in response to an increase in the height of a crop windrow being picked up. A chain is provided between the frame and roll-support arm to limit the downward travel of the arm so as to keep the roll from interfering with the tined pick-up drum. A spring assembly is provided for counterbalancing at least a portion of the weight of the arm and roll assembly so that the roll will easily rise over a relatively light and fluffy crop windrow.

BACKGROUND OF THE INVENTION 
The invention concerns a crop hold down arrangement for a feeder implement, 
such as a pick-up that contains a rotating feeder and a conveyor 
arrangement, with a frame and a rotating roll, whose axis extends parallel 
to the axes of the feeder and/or the conveyor arrangement. 
Hold down arrangements are conventionally used on feeder implements, such 
as pick-up mechanisms, in order to limit the upward movement of crop to be 
lifted by the feeder and to conduct it safely to a conveyor arrangement. 
Known hold down arrangements contain curved rods or prongs, along whose 
underside the crop, such as straw or hay, can slide. U.S. Pat. Nos. 
4,411,127 and 4,495,756 disclose examples of such arrangements. 
Beyond that a hold down arrangement is known from U.S. Pat. No. 4,015,410, 
that contains a rotating roll on a vertically pivoted frame. Due to the 
attitude of the frame, the roll is retained at a small distance from the 
ground, presses the windrow lying there flat and forms a gap with a tined 
pick-up drum, through which the crop is guided to the conveyor 
arrangement. This hold down arrangement has the disadvantage that it can 
escape upward upon changes in the height of the windrow only under high 
pressure and steadily increasing height of the windrow, and thereby, on 
occasion, pushes the crop ahead of itself, which can lead to disruption in 
the supply of the crop. 
In a further hold down arrangement, according to German published 
application 39 22 695, two rolls precede the pick-up drum and the conveyor 
arrangement and are attached rigidly in a vertical direction. This hold 
down arrangement has the disadvantage that variations in the height of the 
windrow can also lead to stoppages and if the conveyor is reversed in 
order to clear a blockage, the ejected crop does not find enough space to 
exit. 
SUMMARY OF THE INVENTION 
According to the present invention, there is provided an improved hold down 
arrangement for a feeder implement, such as a pick-up. 
A broad object of the invention is to provide a hold down arrangement which 
avoids clogging even when picking up unevenly deposited crop. 
A more specific object of the invention is to provide a hold down 
arrangement for a feeder implement, the hold down arrangement including a 
roll which is carried by an arm that is pivotally connected so as to move 
in the direction of movement of crop toward a conveying element of the 
feeder implement if the height of the deposited crop should vary 
considerably. 
Yet another object of the invention is to provide a roll, as set forth in 
the previous object, to which a counterbalance spring may be attached for 
removing the influence of its weight on crop passing therebeneath, 
especially when the crop is relatively light and resilient. 
These and other objects will become apparent from a reading of the ensuing 
description together with the appended drawings.

DESCRIPTION OF THE PREFERRED EMBODIMENT 
FIG. 1 shows a harvesting machine 10 in the form of a self-propelled forage 
harvester having a chassis 12, that is supported on front and rear wheels 
14, 16 so as to be able to move over the ground. The harvesting machine 10 
is controlled from an operator's cab 18, from which a feeder implement 20 
mounted at the front end of the harvesting machine 10 can be viewed. The 
feeder implement 20 takes up crop from the ground and delivers it to a 
chopper assembly 22 that cuts it into smaller pieces and conducts it to an 
impeller arrangement 24 for delivery through an outlet spout 26. 
While in this embodiment, the feeder implement is configured as a so-called 
pick-up of a self-propelled forage harvester, it is to be noted that the 
pick-up 20 can also be used with a pull-type forage harvester, or another 
category of harvester, such as a combine or a baler. When used with a 
combine, the pick-up may be arranged as an accessory that is attached to a 
flange adjacent the feeder house of the combine. 
In any event, the pick-up 20 includes a body 28, a frame 30, a conveying 
arrangement 32, a feeder 34 and a hold down arrangement 36 according to 
the invention with a pivot arm 38 and a roll 40. Although not shown, the 
pick-up 20 may be supported by support wheels on the ground. Further 
details, in particular that of the hold down arrangement 36 are revealed 
in FIG. 2 and the associated description. 
The task of the pick-up 20 consists of taking up crop deposited on the 
ground in windrows which is of varied types and conditions, and to conduct 
it to the harvesting machine 10 for further processing. The crop may 
include grass, wilted silage, grain crops and other feed crops, which may 
be wet or damp as well as very dry and brittle. For this purpose the 
feeder implement 20 is moved during the operation at a small distance from 
the ground, while it is raised for transport on roads or paths. 
The body 28 is a weldment that supports the conveyor arrangement 32 and the 
feeder 34 so that they are powered and can rotate, and that can be 
disassembled from the chassis 12 of the harvesting machine 10. 
The frame 30 is rigidly attached to the upper region of the body 28 and 
extends from there forward to a point considerably beyond the feeder 34. 
The frame 30 can be configured as a U-shaped structure from hollow 
sections, whose legs engage the body 28 and are joined at their forward 
ends to a cross member that extends perpendicular to the direction of 
travel above and ahead of the feeder 34. In its forward end region the 
frame 30 contains two brackets 42 that extend, in general, vertically 
downward, with the two brackets 42 being respectively located on each side 
of the feeder implement 20 with respect to its longitudinal centerline. 
Instead of the rigid attachment of the frame 30 to the body 28, a hinge or 
a pin connection could be provided, that makes it possible to bring the 
frame 30 into a non-operating position or to remove it entirely. 
The conveyor arrangement 32 is located in the rear, upper region of the 
pick-up 20 and is configured as a screw conveyor, which moves the crop in 
known manner from the sides of the feeder implement 20 to a central outlet 
opening, not shown. The rotational axis of the conveyor 32 extends 
generally parallel to the ground and perpendicular to the direction of 
travel of the harvesting machine 10. The conveyor 32 is driven by means 
not shown. 
The feeder 34 is a tined pick-up drum, also of conventional configuration, 
and hence does not require any detailed description. What is significant 
is that the feeder 34 is located below the roll 40 and the conveyor 
arrangement 32 and that its longitudinal axis extends generally 
perpendicular to the direction of travel and parallel to the ground. The 
feeder 34 is also powered by means not shown, and raises the crop from the 
ground with its conveying tines or prongs in order to transfer it to the 
conveyor arrangement 32. The relative position of the conveyor arrangement 
32 to the feeder 34 is fixed. 
The present invention resides in the manner of mounting the hold down 
arrangement 36. Specifically, the hold down arrangement 36 is mounted on 
the brackets 42 of the frame 30 so as to pivot vertically and is designed 
to compress slightly the crop to be picked up and to hold it securely in 
contact with the feeder 34 which then picks it up. 
In this embodiment of the hold down arrangement 36 a total of two pivot 
arms 38 are provided, however, depending on the configuration of the 
embodiment, a single pivot arm 38 may be sufficient. On the other hand, 
with very wide rolls 40, two or three pivot arms 38 may be required. 
Each pivot arm 38 has its front end 44 connected, as by a horizontal pivot 
pin 46 to a bracket 42, to enable the arm to pivot vertically. Each pivot 
arm 38 has its rear end 48 provided with a spherical bearing 50 or a 
rocker bearing receiving and establishing a rotatable mounting for a shaft 
52 of the roll 40. 
Connected between the frame 30 and each arm 38, at a location between the 
rear and front ends 48, 44, is a motion limiting device 54, here shown as 
a chain of a certain length which prevents the pivot arms 38 from moving 
too far downward, so as to prevent the roll 40 from coming into contact 
with the feeder 34. The motion limiting device 54 could also be used to 
retain the arm 38 in a substantially fixed position so as to prevent the 
arm 38 from bouncing during transport. 
Above the bearing 50, a spring device 56 in the form of a mechanical 
helical extension spring has its lower end coupled to each pivot arm 38 
and its upper end coupled to the frame 30. This spring device 56 
counterbalances the weight of the hold down arrangement 36, so that the 
roll 40 does not apply its full weight to the crop being picked up. The 
spring device 56 could also be any other type of mechanical spring or a 
plastic means of applying tension. Similarly a pneumatic spring could be 
used as spring device 56. 
The pivot pin 46 is located ahead of the bearing 50 of each pivot arm 38 so 
that the pivot arms 38 with their rear ends 48 and the roll 40 carried at 
that end can be easily raised by the crop passing beneath the roll 40. 
The roll 40 is supported in such a way that half its diameter covers the 
feeder 34 in the vertical direction; this can be determined by the 
selection of the length of the pivot arms 38 as well as the position of 
the bearing 50 on the arm. The shape of the roll 40 corresponds to a round 
cylinder whose longitudinal axis extends perpendicular to the direction of 
travel of the harvesting machine 10. Its longitudinal axis is located 
vertically between that of the feeder 34 and the conveyor arrangement 32, 
with the outer circumference of the roll being spaced ahead of the outer 
circumference of the conveyor arrangement. This location of the hold down 
roll 40 permits crop to be discharged over the top of the roll when the 
conveyor 32 is reversed to unplug the pick-up. The outer circumference of 
the roll 40 is coated with a lining having a high coefficient of friction, 
to insure that the non-powered roll 40 is brought into rotation by the 
crop as soon as it is in contact with the latter. To further enhance the 
ability of the roll 40 to rotate upon being contacted by crop passing 
therebeneath, the roll could be made to have other than a cylindrical 
outer contour. For example, the roll 40 could be fashioned to have a 
three-, four-, five, six- or eight-sided outer contour.