Guide system for the plunger of a rectangular baler

A rectangular baler having a bale chamber, a compacting plunger and a guide system having at least one guide assembly including a guide element, and a threaded shaft and nut for positioning the guide element, wherein, for receiving said threaded shaft, an elongated slot is provided extending in a slot direction making an angle between 1 and 85 degrees with respect to the discharge direction, the threaded shaft being arranged in an upright position perpendicular to the slot direction.

This application is the US National Stage filing of International Application Serial No. PCT/EP2013/057110 filed on Apr. 4, 2013 which claims priority to Belgian Application BE2012/0241 filed Apr. 10, 2012, each of which is incorporated herein by reference in its entirety.

TECHNICAL FIELD

The present invention relates to a baler, in particular a rectangular baler comprising a plunger, and a guide system for the plunger.

BACKGROUND ART

In rectangular balers, bales are formed by compressing crop material in a bale chamber by a plunger that reciprocates in the bale chamber. The bale chamber typically comprises a top wall, a bottom wall, and two side walls. At one end of the bale chamber there is provided a plunger. The plunger is typically guided in the bale chamber using a plurality of guide rollers and corresponding guide tracks.

An example of a guide system with a plurality of horizontal and vertical rollers and corresponding tracks is disclosed in U.S. Pat. No. 3,059,569 in the name of the Applicant. The vertical rollers, i.e. the rollers with a vertical axis may be adjustable. Each vertical roller is carried on a vertical stud which passes through a slot in a bracket of the plunger. The slot extends in a direction transverse to the bale chamber, and provides a means whereby the roller can be adjusted toward and away from a track member. A problem with such a guide system is that due to the increasing desired density of the bales, increased high forces are exerted on the vertical rollers during a compression stroke. The studs carrying the vertical rollers may be pushed inward in the slot, resulting in misalignment and damage of the guide system.

Another example of a guide system is disclosed in GB 1,161,650. This guide system uses a plurality of guide rollers having an axis making an angle of 45 degrees with respect to a horizontal plane. The guide tracks are arranged in the corners, along the longitudinal edges of the bale chamber. Also in such an embodiment the reaction forces exerted on the rollers during the compression stroke may be high and may lead to problems.

SUMMARY

The object of embodiments of the invention is to provide a baler which addresses the above mentioned problems, and in particular to provide a baler with an improved adjustable guide system.

According to an aspect of the invention there is provided a rectangular baler comprising a bale chamber adapted to contain one or more bales; a compacting plunger adapted for reciprocating in the bale chamber to advance crop material in a discharge direction towards a discharge opening of the bale chamber; and a guide system adapted for guiding the reciprocating of the plunger in the bale chamber. The guide system comprises at least one guide assembly including a guide element and a threaded shaft and nut for positioning the guide element. Further, there is provided an elongated slot for receiving said threaded shaft. The elongated slot extends in a slot direction making an angle between 1 and 85 degrees with respect to the discharge direction. The threaded shaft passes through said elongated slot in an upright position, perpendicular to the slot direction. According to a possible embodiment the slot is arranged in a member fixed to the plunger such that the guide element is fixed to the plunger. Alternatively, it is possible to provide the slot in a member fixed to the bale chamber such that the guide element is fixed to the bale chamber.

Because the threaded shaft is in an upright position in the slot, during reciprocating of the plunger, the threaded shaft is pushed through the guide element in a transverse direction, perpendicular to the discharge direction. Compared to the prior art, where the slot is also arranged in the transverse direction, the direction of the elongated slot of the present invention ensures that the reaction forces exerted via the guide element on the threaded shaft during the reciprocating movement of the plunger can be dealt with in an improved way whilst maintaining the possibility to adjust the position of the guide element in the transverse direction. More in particular, the critical forces for moving the threaded shaft in the elongated slot will be much larger compared to the guide systems of the prior art, where the slot is arranged in a direction transverse of the discharge direction.

According to a preferred embodiment, the angle between the slot direction and the discharge direction is between 2 and 70, more preferably 5 and 45 degrees, and most preferably between 5 and 25 degrees. Typically the angle will be chosen in function of the required adjustment, the available space, and the reaction forces during operation.

According to a preferred embodiment, the slot is arranged in a member fixed to the plunger. More preferably, the slot is arranged in a horizontal plate fixed in a wall of the plunger, wherein the threaded shaft extends vertically through said slot. Especially when the guide elements are rollers, such an embodiment has the advantage that the rollers can be mounted such that the axis extends vertically, wherein the roller is guided against a vertical plane of a member of the bale chamber. However, according to an alternative embodiment, the elongated slots can also be arranged in a plate making an angle with the horizontal plane. Such an embodiment can for example be used in the baler of GB 1,161,650 discussed in the background section, see also the embodiments ofFIGS. 7A and 7Bwhich will be discussed below.

According to a preferred embodiment the guide element is a roller. According to alternative embodiments, the guide element could also be a friction block in a material with a low friction coefficient.

According to a preferred embodiment, the guide element is a roller which is mounted rotatably around the threaded shaft. Such an embodiment has the advantage of being very compact, and of not requiring an additional mounting plate for the roller.

According to an alternative embodiment, the guide assembly comprises a mounting plate on which the guide element is mounted. The threaded shaft is then arranged at the distance of the guide element and passes through the mounting plate for fixing the mounting plate, typically to a member of the plunger. The mounting plate may for example be fixed to a horizontal plate fixed in a recess of the plunger. The slot can be provided either in the mounting plate or in said horizontal plate. In such an embodiment it is preferred to provide two threaded shafts for fixing the mounting plate to the plunger. In that case, two corresponding slots should be provided in the mounting plate or in one or more horizontal plates fixed to the plunger.

According to a preferred embodiment, the compacting plunger has a first side wall and a second side wall, and the at least one guide assembly comprises a first guide assembly arranged at said first side wall, and a second guide assembly arranged at said second guide wall.

According to a further developed embodiment, said guide system further comprises a plurality of horizontal rollers fixed to sidewalls of the plunger. Each horizontal roller has a horizontal rotation axis and is guided in a longitudinal track that is arranged against a side wall of the bale chamber and that extends in the discharge direction.

FIGS. 1,2,2A,3,3A,4and5illustrate a part of an embodiment of a baler of the invention. Only the parts relevant for understanding the present invention are illustrated. Other parts of the baler which are well known to the skilled person, such as the pre-compression chamber, the needle assembly, the knotter devices, the end part of the bale chamber with ejection system, etc. have been omitted. In the bale chamber101there is arranged a compacting plunger103which reciprocates between two side walls106,107. The bale chamber101has an inlet opening (not shown, below the plunger103) and a discharge opening (not shown, at the end of the bale chamber in the discharge direction P). In operation, the compacting plunger103moves from a retracted position to an extended position in the direction of arrow P to advance bales towards the discharge opening. It will be understood that the bale chamber101extends further along the direction P of longitudinal movement of the plunger103, in the usual manner of arranging a bale chamber and plunger.

To guide the plunger103in the bale chamber101, and to support it vertically in the bale chamber, horizontally extending guide tracks111,112are affixed as a part of the bale chamber101. The guide tracks111,112support a first set of rollers113,114at a first side106of the bale chamber, and a second set of rollers115,116at the second side107of the bale chamber, respectively. The rollers113-116are suitably attached to the plunger103, using in the illustrated embodiment brackets123-126. The rollers113-116are in rolling contact with the guides111,112. The rollers113-116have a horizontal rotation axis and the guide tracks111,112have guide surfaces which extend in a horizontal plane.

The guide system further comprises guide assemblies131,132. The guide assembly131is best visible inFIGS. 2 and 2A. The guide assembly131comprises a guide element in the form of a roller133having a vertical rotation axis. The guide assembly131further comprises a vertical threaded shaft134and a nut135for fixing the roller133to the plunger103. The roller133is rotatably connected with the threaded shaft134. The threaded shaft134is fixed in a slot140, using a nut135and fixation ring136. The elongated slot140extends in a slot direction S which makes an angle a with respect to the longitudinal direction L of the bale chamber. In prior art embodiments this angle is 90 degrees in order to allow the adjustment of the roller133in a direction transverse to the longitudinal direction L of the bale chamber. According to embodiments of the invention this angle is chosen between 2 and 70 degrees in order to allow on the one hand a vertical adjustment, and on the other hand to support reaction forces during the reciprocating of the plunger103in an improved manner. The angle is preferably between 5 and 45 degrees, and more preferably between 5 and 25 degrees. In the illustrated embodiment the angle a is between 10 and 25 degrees. In the illustrated embodiment the slot is arranged in a horizontal plate150fixed in a wall160of the plunger103. The horizontal plate150may e.g. be welded in a recess in the wall160.

According to a preferred embodiment, the guide assemblies131,132are symmetrical to each other, allowing an adjustment in a direction transverse to the longitudinal direction L of the bale chamber at both sides106,107of the plunger103. As best shown inFIG. 5, the width dimensions of the slot140are slightly bigger than the diameter of the threaded shaft134in order for the threaded shaft134to be able to pass freely through the slot140. Further, the roller133has a shaft part138with a diameter which is larger than the width of the slot140. This shaft part138is fixed against the horizontal plate150such that the wheel of the roller is located at a distance of the horizontal plate150.

FIGS. 6A and 6Billustrate another possible embodiment of a guide assembly comprising a roller233and a threaded shaft234with nut235to fix the roller233. In the illustrated embodiment ofFIGS. 6A and 6B, the roller233is mounted on a mounting plate239in a traditional manner, wherein the axis of the roller extends perpendicular to the mounting plate239. The wall260of the plunger is provided with a recess in which a first horizontal plate250is fixed. The plate250is provided with a slot240. The slot240extends in a slot direction S, which makes an angle a with the longitudinal direction L of the bale chamber, seeFIG. 6B. The threaded shaft234and nut235fix the mounting plate239with roller233on the horizontal plate250. The slot240allows for the adjustment of the position of the roller233in a direction transverse of the longitudinal direction of the bale chamber201. As illustrated, preferably, two horizontal plates250,250′ are fixed in the recess of the plunger wall260. The plate250′ is also provided with a slot240′ which is arranged at the same location as the slot240in horizontal plate250, seeFIG. 6B. A second threaded shaft234′ with nut235′ connects the mounting plate239to the horizontal plate250′.

The skilled person will understand that still other embodiments are possible using the principle of the invention. Instead of arranging the slots240,240′ in the horizontal plates250,250′, respectively, the slots240,240′ could also be arranged in the mounting plate239. Further, instead of welding the horizontal plate150of the first embodiment in the recess of the plunger wall160, the horizontal plate150could also be fixed in the recess using bolts.

Now a third embodiment of a baler according to the invention will be disclosed with reference toFIGS. 7Aen7B. In this embodiment four guide tracks371-374are provided along the four edges of the bale chamber301. Rollers333are inclined under an angle of 45 degrees with respect to the horizontal plane. Each roller333is mounted between inclined plates350,351which are fixed to the plunger303. As shown inFIG. 7B, each plate350,351is provided with a slot340. The slot extends in a slot direction S which makes an angle a with the longitudinal direction L of the bale chamber301. This angle may be between 2 and 70 degrees. This is best shown inFIG. 7A, where a common vertical threaded shaft334extends through the roller333perpendicular to the plates350,351. The roller333is fixed by screwing nuts335on the end parts of the threaded shaft334. According to an alternative embodiment, there could be provided separate threaded shafts334instead of a common threaded shaft. The slots340will allow the roller333to be adjusted toward and away from the longitudinal edges of the bale chamber301, whilst being able to withstand high reaction forces.

While the principles of the invention have been set out above in connection with specific embodiments, it is to be understood that this description is merely made by way of example and not as a limitation of the scope of protection, which is determined by the appended claims.