Adjusting device for a grindstone of a grinding device of a chopper and method for adjusting a grindstone

Abstract

Adjusting device (20) for a grinding stone (17) of a grinding device (12) of a chopper (10), wherein the grindstone (17) is detachably fixed in a grindstone bushing (38) of a grinding carriage (16) of the grinding device (12), characterized by a guide sleeve (22), an adjusting screw (24) guided in a recess (23) of the guide sleeve (22) via cooperating threads (26, 27), which can be adjusted to the grindstone (17) with an end (25) facing the grindstone (17) received in the grindstone bushing (38).

Description

The invention relates to an adjusting device for a grinding stone of a grinding device of a chopper and to a chopper with such an adjusting device. The invention furthermore relates to a method for adjusting a grinding stone of a grinding device of a chopper with such an adjusting device and to a chopper.CN 102 523 851 A discloses a grinding device for a chopper with a grinding stone holder which is guided by a hand wheel through a guide rod and a push rod through a grinding opening in the housing of the chopper and thus brings a grinding stone into contact with the blades of a chopper drum.U.S. Pat. No. 3,370,628 A discloses a field chopper having a rotating knife drum and a grinding device, the sharpening element of which rests against the rapidly rotating knives of the knife drum. The sharpening element can be adjusted with the aid of a gauge to a specific radial distance from the axis of rotation of the knife drum, so that the knives can be adjusted relative to the exactly positioned sharpening element.DE 41 28 483 C2 discloses a grinding device for chopper blades of a chopper of an agricultural harvesting machine. The grinding device known from this prior art has a grinding carriage which can be displaced along a guide fixed to the housing parallel to an axis of rotation of a chopper drum of the chopper unit carrying the chopper blades, which is rotatably mounted on a housing of the chopper unit. On the grinding carriage, a grinding stone is detachably fixed in a grinding stone bushing. The grinding stone can be adjusted to the chopper blades of the chopper drum via a spindle likewise mounted on the grinding carriage and via a ratchet wheel which is likewise mounted on the grinding carriage and interacts with the spindle, namely in interaction with stops mounted on the housing wall of the housing of the chopper unit and interact with the ratchet wheel mounted on the grinding carriage. When the grinding carriage moves in the direction of a stop fixed to the housing during its movement along the guide fixed to the housing parallel to the axis of rotation of the chopper drum, such a stop engages with the ratchet wheel, whereby the ratchet wheel and thus the spindle cooperating with the ratchet wheel are rotated. The rotational movement of the ratchet wheel and the spindle is converted by the spindle into a linear movement of the grinding stone bushing and the grinding stone in the radial direction of the chopper drum, in order thus ultimately to bring the grinding stone radially with respect to the axis of rotation of the chopper drum to the chopper blades.This automatic readjustment of the grinding stone by the cooperation, known from the prior art, of the respective stop fixed to the housing with the ratchet wheel mounted on the grinding carriage and the spindle which is likewise mounted on the grinding carriage and interacts with the grinding stone bushing and thus with the grinding stone has its limits. The grinding stone bush can only be displaced to a limited extent. It is therefore necessary to reset or reset the grinding stone bushing at defined maintenance intervals and thus to realign the grinding stone to the chopper knives or the chopper drum of the chopper unit. This is also necessary when a grinding stone has to be changed or when the chopper drum is fitted with new or other knives.According to practice, the alignment of a grinding stone to the chopper drum or to the chopper blades of the chopper drum presents difficulties, in particular when resetting the grinding stone bushing. Up to now, it has not been possible to achieve a practicable, simple and reliable alignment of a grinding stone with the chopper drum of a chopper blade when the grinding stone bush is reset.Proceeding from this, the object of the present invention is to provide a novel adjusting device for a grinding stone of a grinding device of a chopper which permits a more precise adjustment of the grinding stone, in particular when the grinding stone bush is set back, and a method for adjusting a grinding stone of a grinding device of a chopper with such an adjusting device.This object is achieved by an adjusting device according to claim 1.The adjusting device according to the invention has a guide sleeve, an adjusting screw which is guided in a recess of the guide sleeve via interacting threads and which can be adjusted to the grinding stone by an end facing the grinding stone accommodated in the grinding stone bush.According to a further development, a plunger guided in a recess of the adjusting screw is provided, which plunger can be pressed against the grinding stone by an end protruding from the adjusting screw and facing the grinding stone via a spring element likewise guided in the recess of the adjusting screw.The invention permits a practicable, simple and reliable alignment of a grinding stone on chopper blades of a chopper drum, in particular when the grinding stone bushing is set back, as is required, for example, when new blades are installed. Incorrect adjustments are prevented, as a result of which the susceptibility to wear is reduced. In particular, by preventing incorrect adjustments of the grinding stone, a collision of the chopper blades with the grinding stone and a risk of damage to the chopper blades and the grinding stone in this respect are avoided. The adjusting device according to the invention enables an accurate adjustment and alignment of the grinding stone with the chopper blades, so that ultimately fewer grinding cycles are required until the grinding stone again makes contact with the chopper blades.Preferably, an internal thread is formed in the recess of the guide sleeve, which interacts with an external thread of a section of the adjusting screw guided in the recess of the guide sleeve. This allows a particularly advantageous adjustment of the adjusting screw to the grinding stone.According to a further development, a stop is formed in the recess of the adjusting screw, which limit the displaceability of the plunger guided in the recess of the guide sleeve in the direction of the grinding stone. As a result, a defined distance can be set between the end of the adjusting screw that can be adjusted on the grinding stone and the end of the plunger that can be adjusted on the grinding stone, whereby a particularly advantageous adjustment and thus alignment of the grinding stone can be carried out.According to a further development, a stop is formed on an outer section of the adjusting screw for the basic setting of the adjusting device when changing chopper blades of the chopper mechanism. This stop is advantageous in particular when new chopper knives are installed on the chopper drum, which lead to a predetermined outer diameter of the chopper drum. This ensures a defined basic setting of the grinding stone for new chopper blades.The method according to the invention for adjusting a grinding stone of a grinding device of a chopper with an adjusting device is defined in claim 7.A chopper with such an adjusting device is defined in claim 8.Preferred developments of the invention are evident from the dependent claims and the following description. Exemplary embodiments of the invention are explained in more detail with reference to the drawings, without being restricted thereto. The following shows: FIG. 1 shows a section of a chopper in the region of a grinding device and an adjusting device for a grinding stone of the grinding device in the radial direction of view; FIG. 2 shows a detail of FIG. 1 in a view rotated through 90° in relation to FIG. 1 in the axial viewing direction in a first position of the adjusting device; FIG. 3 shows the detail of FIG. 2 in a second position of the adjusting device; FIG. 4 shows a detail of FIG. 3 ; FIG. 5 shows the detail of FIGS. 2, 3 in a third position of the adjusting device; FIG. 6 shows a detail of FIG. 5 ; and FIG. 7 shows a further detail of the adjusting device.A chopper unit of an agricultural harvester has a chopper drum with chopper blades. The chopper blades of the chopper drum must be reground during operation, for which purpose the chopper unit has a grinding device.The grinding apparatus has a grinding stone. The grinding stone must be aligned in a defined manner with the chopper blades of the chopper drum. The invention relates to an adjusting device for the grinding stone of a grinding device of a chopper.FIG. 1 shows a detail of a chopper 10 of an agricultural harvester in the region of a chopper drum 11 and a grinding device 12, the chopper drum 11 being rotatably mounted on a housing 13 of the chopper 10, namely via shaft sections 14 of the chopper drum 11 Radially on the outside, the chopper drum 11 carries chopper blades 15.The chopper blades 15 of the chopper drum 11 of the chopper 10 must be reground during operation, for which purpose the grinding device 12 is used. The grinding device 12 has a grinding slide 16 which accommodates a grinding stone 17, namely in a grinding stone bushing 38 in which the grinding stone 17 is releasably fixed, wherein the grinding stone 17 can be displaced via the grinding slide 16 along a guide 19 for grinding the chopper blades 15 parallel to an axis of rotation 18 of the chopper drum 11.During the grinding of the chopper blades 15 of the chopper drum 11, the chopper drum 11 is driven in rotation and the grinding stone 17 is moved parallel to the axis of rotation 18 along the guide 19 by the grinding carriage 16. By grinding the chopper blades 15, the distance between the chopper blades 15 and the grinding stone 17 changes during grinding.In order to compensate for this, it is already known from practice to automatically adjust the grinding stone 17 with respect to the chopper knives 15 via the grinding stone bushing 38 by housing-fixed stops (not shown) interacting with the grinding carriage 16. Here, the stops fixed to the housing typically cooperate with a ratchet wheel (not shown) and a spindle (not shown), which are mounted on the grinding carriage 16 together with the grinding stone 17. This automatic readjustment is fundamentally known from the prior art and does not form the subject matter of the present invention.The automatic adjustment of the grinding stone 17 relative to the chopper blades 15 of the chopper drum 11 during the grinding process known from the prior art has limits.It is thereby necessary to reset the grinding stone bushing 38 at defined maintenance intervals and then to realign the grinding stone 17 with respect to the chopper drum 11 or the chopper blades 15 of the chopper drum 11 in order to always enable an exact re-grinding of the chopper blades 15 within a short time without risk of damage to the chopper blades 15 and the grinding stone 17.The present invention relates to an adjusting device 20 with the aid of which the grinding stone 17 can be aligned with respect to the chopper drum 11 or the chopper blades 15 in a practicable, simple and reliable manner outside a grinding operation of the chopper blades 15 in order to re-align the grinding stone 17 either after a defined number of grinding operations when the limit of the automatic readjustment is reached or also when the grinding stone 17 is changed or when blades are changed.The adjusting device 20 preferably has a holder 21 fastened to the housing 13 of the chopper 10, and the actual adjusting device 20 is mounted on the housing 13 of the chopper 10 via the holder 21.The adjusting device 20 also has a guide sleeve 22 fastened to the holder 21, and the adjusting device 12 also has an adjusting screw 24 which is guided in a recess 23 of the guide sleeve 22 and can be adjusted to the grinding stone 17 by an end 25 facing the grinding stone 17. The grinding stone 17 is here detachably mounted in the grinding stone bushing 38 of the grinding carriage 16.As already stated, the adjusting screw 24 is displaceably guided in the recess 23 of the sleeve 22, wherein an internal thread 26 is formed in the recess 23 of the sleeve 22 and an external thread 27 is formed on the adjusting screw 24, and wherein the internal thread 26 of the guide sleeve 22 interacts with the external thread 27 of the adjusting screw 24. By rotating the adjusting screw 24 in the guide sleeve 22, the adjusting screw 24 can be adjusted either farther toward the grinding stone 17 with the end 25 facing the grinding stone 17, depending on the direction of rotation, or can be adjusted farther away from the grinding stone 17.In addition, the adjusting device 12 has a plunger 28 which is guided in a recess 29 of the adjusting screw 24, wherein not only the plunger 28 but also a spring element 30 is accommodated in the recess 29 of the adjusting screw 24. The plunger 28 guided in the adjusting screw 24 can be pressed against the grinding stone 17 by means of the spring element 30 with an end 31 facing the grinding stone 17. The spring element 30 presses the end 31 of the plunger 28 out of the recess 29 of the adjusting screw 24.The spring element 30 of the adjusting device 20 is supported on the one hand on the plunger 28 and on the other hand on a supporting element 32 which likewise projects in sections into the recess 29 of the adjusting screw 24, wherein the supporting element 32 is screwed in sections into the recess 29 of the adjusting screw 24 at an end 33 of the adjusting screw 24 remote from the grinding stone 17. For this purpose, an internal thread 34, which is formed in sections on the recess 29 of the adjusting screw 24, interacts with an external thread 35 of the supporting element 32.In the region of the recess 29 of the adjusting screw 24, in which the spring element 30 and in particular also the plunger 28 is positioned, no such internal thread is formed. The plunger 28 can be linearly displaced via the spring element 30, namely in such a way that the spring force of the spring element 30 presses the plunger with the end 31 facing the grinding stone 17 out of the recess 29 of the adjusting screw 24, and wherein this end 31 of the plunger 28 can be pressed against the spring force of the spring element 30 into the recess 29 of the adjusting screw 24.In the region of the recess 29 of the adjusting screw 24, a stop 36 is formed in a region facing the grinding stone 17, which limit the displaceability of the plunger 28 in the direction of the grinding stone 17. Then, when the adjusting device 12 according to the invention is not set on the grinding stone 17 as shown in FIGS. 2 and 7 and the spring element 30 presses the plunger 28 against the stop 36, a defined distance Δx is set between the end 25 of the adjusting screw 24 facing the grinding stone and the end 31 of the plunger 28 facing the grinding stone 17.In order to now exactly align a grinding stone 17 with the adjusting device 20 according to the invention, the procedure is such that the adjusting device 20 is initially transferred from the position shown in FIG. 2 into the position shown in FIGS. 3 and 4, for which purpose the adjusting screw 24 is rotated with respect to the guide sleeve 22 and is brought with the end 25 facing the grinding stone 17 into contact with the grinding stone 17, wherein the plunger 28 is displaced against the spring force of the spring element 30 into the recess 29 of the adjusting screw 24, namely until the two ends 25 and 31 of the adjusting screw 24 and plunger 28 run flush with one another and bear flush against the grinding stone 17.The grinding stone 17 in the grinding stone socket 38 is then released, wherein, in particular after a setback or setback of the grinding stone socket 38, the same grinding stone or a new grinding stone in the grinding stone socket 38 is aligned such that, although the end 21 of the plunger 28 of the adjusting device 20 facing the grinding stone 17, the end 25 of the adjusting screw 24 of the adjusting device 20 facing the grinding stone 17 does not abut the grinding stone 17. This relative position of grinding stone 17, plunger 28 and adjusting screw 24 is shown in FIGS. 5 and 6.When the grinding stone 17 is inserted or aligned with the grinding stone sleeve 38 released, a defined gap is therefore formed between the grinding stone 17 and the end 25 of the adjusting screw 24 facing the grinding stone 17. The gap corresponds to the dimension Δx shown in FIG. 7, i.e. the distance between the end 25 of the adjusting screw 24 facing the grinding stone 17 and the end 31 of the plunger 28 facing the grinding stone 17, which presses against the grinding stone 17 and against the stop 36 via the spring force of the spring element 30.The grinding stone 17 is then clamped in the grinding stone bushing 38, wherein, when this clamping is closed, the grinding stone 17 in the grinding stone bushing 38 is displaced by the dimension Δx toward the end 25 of the adjusting screw 24. The dimension of the dimension Δx depends on the grinding stone bushing 38, the grinding stone 17 and / or tolerances.By means of the holder 21, the guide sleeve 23, the adjusting screw 24, the plunger 28 and the spring element 30 are held and permanently fastened to the housing 13 of the chopper 10. The actual position of a grinding stone 17 can be removed by means of the adjusting screw 24 before the grinding stone bush 38 is loosened, namely in such a way that the adjusting screw 24 is displaced in the direction of the grinding stone 17 in such a way that the ends 25 and 31 of the adjusting screw 24 and the plunger 28 both bear flush against the grinding stone 17. Thereafter, the grinding stone sleeve 38 is released and the same is reset. The grinding stone 17 is then aligned in a defined manner, namely in such a way that the grinding stone 17 comes to rest against the end 31 of the plunger 28, but not against the end 25 of the adjusting screw 24. Subsequently, the adjusting device 20 is displaced into the position shown in FIG. 2, namely by the adjusting screw 24 being set off from the grinding stone 17.When using grinding stone bushes 38 which do not cause any displacement of the grinding stone 17 when closing the clamping, the plunger 28 can be dispensed with. In this case, the position of the grinding stone 17 is removed before the subsequent setting or the replacement--as before--by turning the adjusting screw 24 until the end 25 comes to rest against the grinding stone 17. Subsequently, the grinding stone 17 in the grinding stone socket 38 is released, wherein after the grinding stone socket 38 is set back, the same grinding stone 17 or a new grinding stone 17 in the grinding stone socket 38 is aligned such that the end 25 of the adjusting screw 24 of the adjusting device 20 facing the grinding stone 17 abuts against the grinding stone 17. Finally, the grinding stone 17 is clamped in the grinding stone socket 38 by activating the clamping.According to FIG. 7, a stop 37 is formed radially on the outside on a region facing away from the grinding stone 17. This stop 37 serves for the basic alignment of the adjusting device 20 for the installation of new chopper knives 15 on the chopper drum 11 By means of this stop 37 the adjusting device 20 can be aligned in a defined manner with the axis of rotation 15 of the chopper drum 11.Before removing knives which are to be installed again later, the position of the grinding stone can be removed or determined by rotating the adjusting screw 24 until the end 25 comes to rest against the grinding stone 17. In order that the adjusting screw 24 can be adjusted again accordingly later, a relative dimension of the adjusting screw 24 with respect to the grinding stone bushing 38 or e.g. the distance between the stop 37 and the guide sleeve 22 must be measured and noted.List of reference characters10 Chopper 11 Chopper drum 12 Grinding device 13 Housing 14 Shaft 15 Chopper blade 16 Grinding slide 17 Grinding stone 18 Axis of rotation 19 Guide device 20 Adjusting device 21 Holder 22 Guide sleeve 23 Recess 24 Adjusting screw 25 End 26 Internal thread 27 External thread 28 Plunger 29 Recess 30 Spring element 31 End 32 Support element 33 End 34 Internal thread 35 External thread 36 Stop 37 Stop 38 Grinding stone bushing

Claims

Adjusting device (20) for a grinding stone (17) of a grinding device (12) of a chopper (10), wherein the grinding stone (17) is releasably fixed in a grinding stone bushing (38) of a grinding carriage (16) of the grinding device (12), characterized a guide sleeve (22), an adjusting screw (24) guided in a recess (23) of the guide sleeve (22) via cooperating threads (26, 27), which adjusting screw can be adjusted to the grinding stone (17) by an end (25) facing the grinding stone (17) accommodated in the grinding stone bush (38).Adjusting device according to Claim 1, characterized in that a plunger (28) which is guided in a recess (29) of the adjusting screw (24) is provided and can be pressed against the grinding stone (17) by means of an end (31) which faces the grinding stone (17) by means of a spring element (30) which is likewise guided in the recess (29) of the adjusting screw (24).Adjusting device according to claim 1 or 2, characterised in that an internal thread (26) is formed in the recess (23) of the guide sleeve (22), which interacts with an external thread (27) of a section of the adjusting screw (24) guided in the recess (23) of the guide sleeve (22).Adjusting device according to Claims 2 and 3, characterized in that a stop (36) is formed in the recess (29) of the adjusting screw (24), which stop limits the displaceability of the plunger (28) guided in the recess (29) of the adjusting screw (24) in the direction of the grinding stone (17).Adjusting device according to one of Claims 1 to 4, characterized in that a stop (37) for the basic setting of the adjusting device (20) for the installation of new chopper knives (15) of the chopper (10) is formed on an outer section of the adjusting screw (24).Adjusting device according to one of Claims 1 to 5, characterized bya holder (21) which is fastened to a housing (13) of the chopper (10) and to which the guide sleeve (22) is fastened.Method for adjusting a grinding stone (17) of a grinding device (12) of a chopper (10) with an adjusting device (20) according to one of Claims 2 to 6, characterized bythe following steps: the adjusting screw (24) is rotated with respect to the guide sleeve (22) and brought with the end (25) facing the grinding stone (17) into contact with the grinding stone (17), namely in such a way that the plunger (28) is pressed into the recess (29) in the adjusting screw (24) counter to the spring force of the spring element (30) in such a way that the end (31) of the plunger (28) facing the grinding stone (17) and the end (25) of the adjusting screw (24) facing the grinding stone (17) bear flush against the grinding stone (17), and the grinding stone (17) is then released in the grinding stone bush (38), and the same grinding stone (17) or a new grinding stone (17) in the grinding stone bush (38) is oriented such that although the end (31) of the plunger (28) facing the grinding stone (17) but not the end (25) of the adjusting screw (24) facing the grinding stone (17) abuts on the grinding stone (17) to form a gap between the grinding stone (17) and the adjusting screw (24); subsequently, the grinding stone (17) is clamped in the grinding stone bush (38).Chopper (10) of an agricultural harvester having an adjusting device (20) according to one of Claims 1 to 6.

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