The present invention generally relates to a support base for a toolholder of a milling drum, and in particular to a tool arrangement on milling drums of scarifiers.
Scarifiers are working machines used for working and removing soils, in particular for making roads. In their standard constructional form these machines are provided with a milling drum having a plurality of active elements, e.g. cutting or milling elements, that—during rotation of the milling drum—come into contact with the surface to be removed and crush it.
In some prior art scarifiers, each active element is a tool arrangement consisting of a support base fixed to the tubular body of the milling drum, wherein the support base accomodates a respective toolholder in which a milling tool is removably inserted, for example, by pressing it into the toolholder.
The active elements are arranged on the milling drum corresponding to one or more right hand and left hand spirals starting from both ends of the milling drum and meeting at a central location on the milling drum. The required pitch of the spirals defined by the active elements varies according to the kind of soil to be worked on. Specifically, small pitches are adapted to work on hard asphalt and to carry out soil forming while large pitches are particularly adapted to carry out digging on concrete or soft mix.
For optimizing the working process, it is desired to have for each scarifier a couple of drums available, whereby these drums are provided with different pitches of the tools supported thereon so as to adapt the scarifier to the kind of soil to be worked on. In order to avoid the necessity of changing milling drums, it is known to provide a single milling drum with double threaded spirals having a small pitch, and thus adapted to work on hard asphalt or to carry out forming. Such a milling drum may be used also to carry out diggings on concrete or soft mix by removing the toolholders with the relevant tools arranged in the support bases along one of the adjacent spirals. Then, the same milling drum has the active elements arranged on a single spiral having a pitch which is about doubled to the previous one, so that it can efficiently be used for digging concrete or soft mix as well.
There are various support bases known in the art, which generally have to be of a solid construction to provide the required stability during operation of the milling drum. This constructions may be so volumnous that an empty support base interferes with a tool remaining on the milling drum. Also, in order to fixedly mount the toolholders to the respective support bases reliable connection means are required which often render the assembly and disassembly of the toolholders labour intensive.
In accordance with the present invention an easy and quick replacement of tools on a milling drum is facilitated by constructing the required support base and the support portion associated with respective tools more compact without compromising stability. Further, the present invention also provides for the protection of empty support bases for toolholders against damage resulting from contact with the soil to be removed by applying a protection cover adapted to be inserted and fastened to the respective support bases and also by allowing a greater distance between the empty support bases and the soil to be worked on.
According to one aspect of the invention this is achieved by providing a support base adapted to be mounted to the surface of a milling drum. The support base includes a recess adapted to receive removably a shank portion of a body, either a toolholder or a protection cover, to be fixedly mounted to said support base. The recess has a first side surface facing into the direction of rotation of the milling drum and being adapted to contact the shank portion. The support base further comprises a reaction surface adjacent to the first side surface and also facing in the direction of rotation, wherein the reaction surface is disposed at an angle of more than 180° with respect to said first side surface. The reaction surface is adapted to bear against a support surface of the body to be inserted into the support base and advantageously takes up forces applied to the body so as a lower constructional height of the support base is achievable.
According to a further aspect of the invention, a body adapted to be fixed to a support base mounted to the surface of a milling drum is provided. The body includes a shank portion adapted to be received in a recess of the support base. The shank portion includes a first side surface adapted to bear against a first side surface of the recess. The body further includes a second portion above and adjoining said shank portion and forming a first support surface adjacent to the first side surface and being inclined thereto. The support surface on the second portion and the first side surface on the shank portion form an obtuse angle. The first support surface is adapted to firmly bear against a reaction surface of the support base facing in a direction of rotation of the milling drum.
In another aspect of the invention, a support base is provided which is adapted to be mounted to the surface of a milling drum. The support base includes a recess for receiving removably a shank portion of a body to be fixedly mounted to said support base. The recess is at least partly formed by a wall including a slot open at one end for insertion of a fastening means into said slot for fixing said body to said support base. The slot and thus the support base can be provided with a minimum height just to receive the fastening means and preferably a stabilizing tongue portion projecting from the shank portion of the body.
In still another aspect of the invention, a body adapted to be fixed to a support base mounted to the surface of a milling drum is provided, wherein the body includes a shank portion adapted to be received in a generally C-shaped recess of the support base. The body further includes a tongue portion connected to the shank portion and extending away therefrom. The tongue portion is adapted to be slidingly received in an opening formed in a rear wall of said recess.
The foregoing and other objects and advantages of the present invention will be better understood upon reading the following detailed description of a preferred embodiment of the invention when read in the light of the accompanying drawings in which:
With reference to
Preferably the support base 1 is an integral piece of metal and is fixedly mounted onto the surface 2 by welding. As can be seen in
The recess 4 of the support base 1 receives shank portions 14 and 21 of the toolholder 5 and the protection cover 7, respectively. The recess 4 is formed by a first side surface 101 on the inner side of a first side wall 117 and facing in the direction of rotation of the milling drum, a second side surface 102 provided by a second side wall 118 and opposite to the first side surface 101, and a third side surface 104 which is provided by a rear wall 103 and extends in the direction of rotation of the milling drum. The first, second, and third side surfaces 101,102, and 104 form a generally C-shaped first seat 10 of the support base opening in an axial direction of the milling drum whereby opposite to the rear wall 103 the recess 4 is open for insertion of the shank portions 14 and 21. As can be seen in the top plan view of
Again with reference to
The support surface 112 is located opposite to the reaction surface 111 and adjacent the second side surface 102 of the recess 4. As the reaction surface 111, the support surface 112 is inclined to the second side surface 102 and forms with the second side surface 102 an angle of more than 180°. Preferably, the reaction surface 111 and the support surface 112 are inclinded by the same amount with respect to the first and second side surfaces 101 and 102. Further, peferably they converge only in the vertical downward direction, i.e. towards the first seat 10, whereas in the horizontal direction they extend parallel to each other.
Between the first side surface 101 and the reaction surface 111 as well as between the second side surface 102 and the support surface 112, the support base 1 comprises respective grooves 113 and 114 mainly to avoid any protrusions in that area to ensure positive contact between the first and second side surfaces 101, 102, the reaction surface 111 and the support surface 112 and respective surfaces of the body 5 or 7 to be held by the support base 1 (see
With further reference to
As mentioned above, the rear wall 103 forms the third side surface 104 which is generally plane and has the same vertical orientation as the first and second side surfaces 101 and 102, e.g. generally perpendicular to a plane tangent to the surface 2 of the milling drum 3. An outer surface 105 of the rear wall 103 has an undercut 106 formed therein which at least covers the area around the slot 8. In its simplest form, as a width 84 of the slot 8 is lower than the width of the rear wall 103 in which the slot 8 is formed, the undercut 106 is provided for the full width of the rear wall 103 as shown in
As generally shown in
The support base 1 further comprises a lateral hole or recess 12 formed in the first side wall 117 and cutting out a portion of the reaction surface 111 of the second seat 11. The lateral hole 12 is oriented so as to define an inclined longitudinal axis 40 which coincides with a tool axis 60 of the toolholder 5 and the relevant tool 6 (see
Now referring to the toolholder 5, as generally shown in
As mentioned above, the lateral hole 12 provided in the support base 1 and shown in
With reference to
The shank portion 14 comprises first, second and third side surfaces 141, 142, and 143 which are adpted to cooperate with the first to third side surfaces 101, 102, and 104 of the first seat 10. The tongue portion 16 extends away from the third side surface 141. The second portion 15 comprises first and second support surfaces 151 and 152 which are adapted to cooperate with the reaction surface 111 and the support surface 112 of the second seat 11, respectively.
With reference to
Preferably, as seen in
In
The shank portion 14 of the toolholder 5 has an outer surface 190 opposite to the third side surface 143 both of which are intersected by the through hole 17. The third side surface 143 abuts against the third side surface 104 of the recess 4 when the toolholder 5 is inserted into the support base 1. On the other hand, the outer surface 190 is exposed and comprises an undercut 19 which is formed to receive non-rotatably a portion of the fastening means 9. The undercut 19 provides a datum plane 191 which prevents unthreading of the fastening means 9, as will be described below.
The fastening means 9 in turn, as shown with particular reference to
Further, as shown in
The protection cover 7 is also adapted to be fixed to the support base 1 in a similar manner to the toolholder 5. As shown in
With reference to
The shank portion 21 is formed by first to third side surfaces 211 to 213 adapted to cooperate with the first to third side surfaces 101, 102 and 104 of the first seat 10. The second portion 22 comprises first and second support surfaces 221 and 222 adapted to cooperate with the reaction surface 111 and the support surface 112 of the second seat 11, respectively (see
A through hole 24 is provided in the shank portion 21 and the tongue portion 23 of the support portion 20 with the tongue portion 23 located at an upper side of the through hole 24. As the through hole 17 of the toolholder 5, the through hole 24 is adapted to receive the fastening means 9 consisting, as described above, of the screw 91 with the driving head 92 and the tightening nut 93 (see
As shown in more detail in
In order to fix the toolholder 5 to the support base 1, it is sufficient to slidingly insert the support portion 13 into the recess 4, paying attention that the tongue portion 16 of the support portion 13 is inserted into the slot 8. The C-shaped profile of the first seat 10 and the dovetail profile of the second seat 11 facilitate an easy and quick insertion of the toolholder 5 into the support base 1. In particular, the converging first and second side surfaces 101 and 102 of the support base 1 in cooperation with the first and second side surfaces 141 and 142 allow centering and firm locking of the shank portion 14 in the first seat 10 against the wall 103. The second seat 11 in cooperation with the first and second support surfaces 151 and 152 on the second portion 15 of the toolholder acts as sliding guidance or rail when inserting the toolholder 5 into the support base 1.
After coupling into the support base 1, the toolholder 5 is fixed or blocked from removing by inserting the screw 91 through the shank portion 14 and the slot 8. The screw 91 is then tightened by the nut 93 until its base 94 bears against the outer surface 105 of the wall 103.
The wedge shaped gap between the second support surface 152 and the support surface 112 of the second seat 11 on the forward side of the toolholder 5 warrants absence of play between the first support surface 151 and the reaction surface 111 of the support base 1 when the screw 9 blocks the toolholder 5 in the recess 4.
After having inserted the desired number of toolholders 5 in corresponding support bases 1, the milling drum 3 is ready to be used. As indicated in
In operation, the tools 6 apply forces on the toolholders 5 generally along the tool axis 60. A major part of those forces is advantageously taken up by the reaction surface 111 of the support base 1 which directs the forces through the wall 117 towards the milling drum 3. Thus, less shear forces are transmitted through the shank portion 14 of the toolholder to the first side surface 101 of the recess 4. This increases the stability of the support bases 1 and allows building them with a lower height. In particular, the body portions 51 of the toolholders 5 may project from the support bases 1 by a considerable amount without compromising the stability of the toolholder support portions 13 kept in the support bases 1. Thus, the tips of the tools 6 can be arranged further away form the support bases 1 on the milling drum 3.
In particular, when the milling drum 3 is provided with parallel spirals of the support bases 1, the toolholders 5 applied to the support base spirals can be arranged more densely so as to adapt the milling drum 3 for grinding operations. On the other hand, if it is desired to adapt the milling drum 3 to a different work condition by removing the toolholders 5 from selected ones of the spirals, the support bases 1 of the respective emptied spirals can be covered with the covers 7, as shown in
Especially when the drum is operated for a rather long period of time the toolholders 5 may frequently get strongly stuck to the corresponding support base. However, with the design of the support bases 1, the toolholders 5 can be more readily loosened from the support bases 1 because the support bases 1 with a lower height have a lower surface area onto which the surfaces of the shank portions 14 of the toolholders 5 may get stuck.
As the support bases 1 can be constructed with a quite low height and also the covers 7 do not project by a significant amount from the support bases 1, the support bases 1 not equipped with toolholders 5 do not interfere with the toolholders 5 remaining on the milling drum. In other words, the tools 6 held by the toolholders 5 can dig deeper into the ground or road surface.
Therefore, the free support bases 1 are not prone to be damaged seriously in consequence of contacting the soil to be removed.
Also, the provision of the slot 8 for receiving the fastening means 9 helps in lowering the height of the support bases 1. In fact, the slot 8 has only to be provided with a minimum depth so as to receive the screw 91. The height of the rear wall 103 including the slot 8 is mainly determined by the size of the nut 93, as can be seen for example in
It also has to be noted that for disassembly or removal and also for subsequent mounting of the toolholders 5 or the protection covers 7 from and onto the support bases 1, the screws 91 never have to be completely unthreaded and taken out from the shank portions 14 and 21 of the toolholders 5 and protection covers 7, respectively. Advantageously, it is sufficient to loosen the nut 93 by an amount sufficient to take it out from the undercut 106 of the support base 1 in order to remove the screw 91 from the slot 8. The fastening means 9 is then kept with the toolholder 5 or the protection cover 7 and does not get lost so easily.
While a specific embodiment of the invention has been described and shown in detail, it should be appreciated that to those skilled in the art various modifications and alternatives of details may occur in the light of the overall teachings of the disclosure. For example, the fastening means 9 consisting of a screw 91 and a nut 93 may be modified by permanently attaching a stud to the shank portion 14 or 21, the stud being provided with a threaded surface to receive a corresponding nut. Thus, it is intended to take the above description as illustrative only and not limiting as to the scope of the invention which is defined by the appended claims and all equivalents thereof.
Number | Date | Country | Kind |
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VI2001A0100 | May 2001 | IT | national |
Filing Document | Filing Date | Country | Kind | 371c Date |
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PCT/EP02/05104 | 5/8/2002 | WO | 00 | 11/5/2003 |
Publishing Document | Publishing Date | Country | Kind |
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WO02/090717 | 11/14/2002 | WO | A |
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