Patent Description:
The prior art includes milling attachments having dual drive motors as for example disclosed in <CIT>. In such a system two separate hydraulic motors drive opposite ends of the milling drum of the milling attachment. In prior art designs both of the drive motors are connected to the milling drum by threaded connectors, thus requiring a complex mechanical arrangement to allow for the assembly and disassembly of the milling drum with the milling attachment and to allow for thermal expansion of the milling drum during milling operation.

There is a need for improved assembly arrangements allowing for faster and less labor intensive procedures for removing and replacing the milling drum of a milling attachment having dual drives.

In one embodiment a milling attachment for a work machine includes a frame including first and second frame side walls. A motor mounting plate is removably mounted on the second frame side wall. A milling drum includes first and second mounting flanges. A first drive motor is mounted on the first frame side wall and includes a drive end connected to the first drum mounting flange by a plurality of threaded fasteners. A second drive motor is mounted on the motor mounting plate and connected to the second drum mounting flange by a stab-in non-threaded connector.

The second drum mounting flange may include a central opening and a plurality of radially offset openings. The stab-in non-threaded connector may include a center hub mounted on the second drive motor and configured to be received in the central opening, and a plurality of radially offset pins configured to be received in the plurality of radially offset openings.

The plurality of radially offset pins may include at least three radially offset pins. The pins may be equally spaced circumferentially around the center hub.

In any of the above embodiments, the center hub may include a cylindrical outer bearing surface configured to be closely received in the central opening, and the center hub may include a tapered axial end configured to guide the cylindrical outer bearing surface into the central opening.

In any of the above embodiments, the center hub may include an inside diameter equal to at least <NUM>% of an inside diameter of a drum casing of the milling drum to allow access through the center hub to a plurality of fasteners connecting the center hub to the second drive motor.

In any of the above embodiments, the center hub may have an open axial end to allow access through the center hub to a plurality of fasteners connecting the center hub to the second drive motor.

In any of the above embodiments, the stab-in non-threaded connector may include a base plate having a generally circular mid-portion with three protruding lobes, and the plurality of radially offset pins may include three radially offset pins one of which is mounted on each of the lobes.

In any of the above embodiments, the central opening of the second drum mounting flange may have a diameter equal to at least <NUM>% of an inside diameter of a drum casing of the milling drum to allow access to the fasteners connecting the first drive motor to the first drum mounting flange.

In any of the above embodiments, the first and second drive motors may be hydraulic motors.

In any of the above embodiments, the first and second hydraulic motors may be completely received between the first frame side wall and the motor mounting plate. In any of the above embodiments, the milling attachment frame may include a back plate configured to be mounted on the work machine.

In another embodiment a method of removing a milling drum from a milling attachment of a work machine, may include steps of:.

In the above method the motors may be hydraulic motors, and the method may be performed without disconnecting any hydraulic hoses from the hydraulic motors.

Numerous objects, features and advantages of the present invention will be readily apparent to those skilled in the art upon a review of following description in conjunction with the accompanying drawings.

Referring now to the drawings <FIG> shows a left side elevation view of a work machine <NUM> carrying a milling attachment <NUM>. As used in the following description the terms "left" and "right" are from the viewpoint of an operator of the work machine sitting in the operator's station <NUM> and facing forward. The work machine <NUM> is shown as a skid steer loader, such as for example a John Deere model <NUM> loader. The work machine <NUM> may also take other forms, such as for example an excavator such as a John Deere model <NUM> excavator. Milling attachments of this type are used on such work machines to mill a ground surface to remove a portion of the ground surface. The ground surface is often a paved surface made of asphalt or concrete. The milling may be a preface to a repaving of the ground surface.

The work machine <NUM> may include a machine frame <NUM> supported from a ground surface <NUM> by a plurality of ground engaging units <NUM> so that the work machine <NUM> is a self-propelled work machine. The ground engaging units <NUM> are shown as wheels but tracked ground engaging units may also be used. An operator's station <NUM> is carried on the machine frame <NUM>. A boom <NUM> is pivotally connected to the machine frame <NUM> at <NUM> and can be raised and lowered relative to the machine frame <NUM> by lift cylinders such as <NUM>. The boom <NUM> carries an attachment mounting frame <NUM> which may also be referred to as a manipulation frame <NUM>. An implement actuator cylinder <NUM> can pivot the attachment mounting frame <NUM> relative to the boom <NUM>. It will be understood that the attachment mounting frame <NUM> is a standard part of a work machine that is designed to allow various tool attachments to be mounted on the work machine <NUM> and manipulated relative to the machine frame <NUM> by operation of the actuators <NUM> and <NUM>.

<FIG> shows a left front perspective view of the milling attachment <NUM>, and <FIG> shows a left side elevation view of the milling attachment <NUM>. In <FIG> the work machine <NUM> and its connection to the milling attachment <NUM> are schematically represented as further described below.

The milling attachment <NUM> includes a milling attachment frame <NUM> including first and second integral frame side walls <NUM> and <NUM>, a frame back wall <NUM> and a frame top <NUM>. The first and second integral frame side walls <NUM> and <NUM>, the frame back wall <NUM> and the frame top <NUM> collectively form a milling drum housing <NUM> within which is received a milling drum <NUM>. A motor mounting plate <NUM> (see <FIG>) is removably mounted on the second frame side wall <NUM> by a plurality of threaded connectors such as <NUM>.

As best seen in <FIG> the milling drum <NUM> includes a tubular milling drum body or casing <NUM> and first and second internal drum mounting flanges <NUM> and <NUM> extending radially inward from the casing <NUM>. A plurality of cutting bits <NUM>, only two of which are shown in <FIG>, are mounted on the casing <NUM> and as the milling drum <NUM> is rotated about a milling drum axis <NUM> the cutting bits <NUM> define a cutting circle or milling circle shown in dashed lines as <NUM>.

As further seen in <FIG>, the milling attachment <NUM> is a dual drive milling attachment including first and second drive motors <NUM> and <NUM>. The motors <NUM> and <NUM> are shown as hydraulic motors, but in another embodiment they could be electric motors. The first drive motor <NUM> is mounted on the first frame side wall <NUM> via an adapter <NUM> by a plurality of threaded connectors such as <NUM> and includes a drive end <NUM> connected to the first drum mounting flange <NUM> by a plurality of threaded fasteners <NUM>.

The second drive motor <NUM> is mounted on the motor mounting plate <NUM> via an adapter <NUM> by a plurality of threaded connectors such as <NUM>. A stab-in non-threaded connector <NUM> is mounted on a drive end <NUM> of second motor <NUM> by a plurality of threaded connectors <NUM>. As can be seen in <FIG> the second drive motor <NUM> is connected to the second drum mounting flange <NUM> by the stab-in non-threaded connector <NUM>.

As best seen in <FIG> the second drum mounting flange <NUM> includes a central opening <NUM> and a plurality of radially offset openings 90A, 90B and 90C. The openings <NUM> and <NUM> may be circular openings. The central opening <NUM> has a diameter preferably equal to at least <NUM>% of an inside diameter of the drum casing <NUM> in order to provide access to the fasteners <NUM> to connect the first drive motor <NUM> to the first drum mounting flange <NUM>.

The stab-in non-threaded connector <NUM> is shown in isolation in <FIG>. Connector <NUM> includes a center hub <NUM> and a plurality of radially offset pins 94A, 94B and 94C. As seen in <FIG> the center hub <NUM> is configured to be received in the central opening <NUM> and the pins 94A, 94B and 94C are configured to be received in the radially offset openings 90A, 90B and 90C, respectively. In an embodiment there are three pins <NUM>. In another embodiment there may be more than three pins <NUM>. In an embodiment the pins <NUM> may be equally spaced circumferentially around the center hub <NUM>.

The stab-in non-threaded connector <NUM> includes a base plate <NUM> to which the center hub <NUM> is welded as indicated at <NUM>. As best seen in <FIG> the base plate <NUM> may have a generally circular mid portion <NUM> with three protruding lobes 102A, 102B and 102C. The stab-in non-threaded connector <NUM> may be manufactured by starting with a sheet of steel having a profile as seen in <FIG>. Then a piece of tubular steel stock, which will form the hub <NUM>, may be welded to the steel sheet which forms the base plate <NUM>. Then the various recesses and surfaces shown in <FIG> may be formed by machining processes. The base plate <NUM> may have a circular recess <NUM> formed therein for receiving the drive end <NUM> of second drive motor <NUM>. A central opening <NUM> may be formed through the base plate <NUM> concentric with the circular recess <NUM>. Surrounding the central opening <NUM> a plurality of holes <NUM> may be provided for receiving the threaded fasteners <NUM> (see <FIG>). Each of the three lobes 102A, 102B and 102C may have a bolt hole <NUM> formed therethrough and surrounded by a countersunk recess <NUM> on the same side as the hub <NUM>. Pins 94A, 94B and 94C are received in the three countersunk recesses <NUM> and held in place by bolts <NUM>. Each pin <NUM> may include a cylindrical end portion <NUM> to be received in its respective radially offset opening <NUM>, and an enlarged base portion <NUM> which sits in its respective countersunk recess <NUM>.

The hub <NUM> may have a cylindrical outer bearing surface <NUM> formed thereon and configured to be closely received in the central opening <NUM> of the second drum mounting flange <NUM>. Adjacent the cylindrical outer bearing surface <NUM> may be a reduced diameter guide surface <NUM> and then a tapered axial end <NUM> configured to guide the cylindrical outer bearing surface <NUM> into the central opening <NUM> during the stab-in procedure. The hub <NUM> has an open axial end <NUM> defining an inner access opening to provide access to the threaded fasteners <NUM>. Access opening <NUM> may be defined by an inside diameter <NUM> of hub which is preferably equal to at least <NUM>% of an inside diameter of the drum casing <NUM>.

As seen in <FIG>, the first and second hydraulic motors <NUM> and <NUM> may be completely received between the first frame side wall <NUM> and the motor mounting plate <NUM>, thus providing a compact assembly.

The arrangement described above for the mounting of the hydraulic motors <NUM> and <NUM> provides for an improved method of installing and/or removing the milling drum <NUM> in the milling attachment <NUM>, especially as compared to prior art dual motor milling attachment designs. In prior art designs both of the drive motors are connected to the milling drum by threaded connectors, thus requiring a complex mechanical arrangement to allow for the assembly and disassembly of the milling drum with the milling attachment and to allow for thermal expansion of the milling drum <NUM> during milling operation.

With the arrangement of the present disclosure the milling drum <NUM> may be removed by a method including steps of:.

With this arrangement the milling drum <NUM> may be removed without disconnecting any hydraulic hoses such as <NUM> and <NUM> (see <FIG>) from the hydraulic motors <NUM> or <NUM>.

In the above procedure the milling drum <NUM> may be rested on a wooden pallet or the like prior to step (a) so that the milling drum <NUM> is temporarily supported during steps (a) and (b). Then step (c) may be performed with the aid of a fork lift or the like engaging the wooden pallet to remove the milling drum <NUM>.

Installation of the milling drum may be performed by a reversal of the steps described above. To install the milling drum <NUM> it is first moved into position adjacent the first drive motor <NUM> and the first set of threaded fasteners <NUM> are installed to connect the milling drum to the first drive motor <NUM>. Then the stab-in non-threaded connector <NUM>, which is attached to the motor mounting plate <NUM> is stabbed into the milling drum <NUM> by an axial sliding motion so that the center hub <NUM> is received in the center opening <NUM> of second drum mounting flange <NUM> and the pins <NUM> are received in the radially offset openings <NUM>. Then the motor mounting plate <NUM> is attached to the second frame side wall <NUM> by threaded fasteners <NUM> to complete the installation.

As best seen in <FIG>, the frame top <NUM> of the milling drum housing <NUM> may include a movable front cover portion <NUM>. The movable front cover portion <NUM> may be in the form of an elongated plate which is pivotally connected to the first and second frame side walls <NUM> and <NUM> by pivot pins <NUM> and <NUM>. A lower edge portion <NUM> of the movable front cover portion <NUM> may be formed of a flexible elastomeric material to aid in sealing against the ground surface <NUM>.

First and second adjustable side plates <NUM> and <NUM> are mounted on the first and second frame side walls <NUM> and <NUM>, respectively. Each side plate has a ground engaging portion <NUM> which is configured for engaging the ground surface <NUM>. Ground engaging portions <NUM> may be in the form of a skid. The details of construction of the first adjustable side plate <NUM>, and further details of the mounting of milling attachment <NUM> on the work machine <NUM> are seen in <FIG>.

A three-dimensional reference system is shown in <FIG> wherein Ro is the roll axis of the work machine <NUM>, Gi is the yaw axis of the work machine <NUM> and Ni is the pitch axis of the work machine <NUM>. The reference system also applies to the milling attachment <NUM> when it is held in the position shown in <FIG>. The work machine <NUM> is schematically indicated in <FIG> as including the machine frame <NUM> and the attachment mounting frame <NUM>. Between the attachment mounting frame <NUM> and the back plate <NUM> of the milling attachment frame <NUM> is a lateral displacement device <NUM> by which the milling attachment <NUM> may be displaced parallel to the rotational axis <NUM> of milling drum <NUM> and also parallel to the pitch axis Ni of work machine <NUM> in a translatory fashion over a displacement width that is specified by the work machine <NUM> and/or by the mounting frame <NUM> and/or by the lateral displacement device <NUM> itself.

As is further schematically shown in <FIG> the back plate <NUM> in turn may be connected to the lateral displacement device <NUM> by a pivotal mounting <NUM> so that the milling attachment <NUM> is tiltable about a tilt axis <NUM> that is parallel to the roll axis Ro of work machine <NUM> and/or orthogonal to the rotational axis <NUM> of the milling drum <NUM>. This allows the work machine <NUM> to perform a rolling motion about its roll axis Ro without thereby disadvantageously influencing the milling attachment <NUM> during a ground milling operation. The tilt axis <NUM> preferably intersects milling drum axis <NUM>. Alternatively, tilt axis <NUM> may cross milling drum axis <NUM>, preferably at a distance of no more than half of the radius of milling circle <NUM>, in order to keep a tilt arm between tilt axis <NUM> and milling drum axis <NUM> advantageously short. Using a tilt actuator <NUM> it is possible to control a tilt angle of the milling attachment <NUM> relative to the work machine <NUM>.

In the illustrated embodiment the first adjustable side plate <NUM> is formed in two parts, namely an upper first lift component <NUM> and a lower first swivel component <NUM> supported on the first lift component <NUM> to be swivel able about a first swivel axis <NUM>. The ground engaging portion or skid <NUM> is integrally formed on the first swivel component <NUM>. The skid <NUM> may also be a replaceable wear part that is attached to the side plate in a replaceable manner.

A first actuator <NUM> is operably associated with the first adjustable side plate <NUM> for raising and lowering the first adjustable side plate <NUM> relative to the first frame side wall <NUM> to adjust the height of the first frame side wall <NUM> and the milling drum <NUM> relative to the ground surface <NUM>. Similarly, a second actuator <NUM> is operably associated with the second adjustable side plate <NUM> for raising and lowering the second adjustable side plate <NUM> relative to the second frame side wall <NUM> to adjust the height of the second frame side wall <NUM> and the milling drum <NUM> relative to the ground surface <NUM>. The first and second actuators <NUM> and <NUM> are independently operable so that a milling depth of the milling drum <NUM> can be adjusted on either side of the milling attachment <NUM>.

The first actuator <NUM> includes a first pivot arm <NUM> and a first hydraulic cylinder <NUM>. The first pivot arm <NUM> is mounted on the milling attachment frame <NUM> and operably connected to the first adjustable side plate <NUM> at connection <NUM>. The first pivot arm <NUM> is a three-dimensional structure including an axially inner arm member <NUM>, an axially outer arm member <NUM> and a bridge <NUM> rigidly connecting the axially inner and outer arm members <NUM> and <NUM>. A pivot shaft <NUM> extends between projections <NUM> and <NUM> of the milling attachment frame <NUM>. The axially inner and outer arm members <NUM> and <NUM> are mounted on the shaft <NUM> so that the entire pivot arm <NUM> is pivotable about axis <NUM> of shaft <NUM>. An arcuate shaped scale <NUM> is fixed to and pivots with pivot arm <NUM>. A pointer <NUM> (see <FIG>) is fixed relative to the milling attachment frame <NUM> so that as the first pivot arm <NUM> is pivoted by the hydraulic cylinder <NUM> the scale <NUM> moves relative to the pointer <NUM> to provide a visual indication of the height of the first side plate <NUM> and the corresponding milling depth <NUM>.

First actuator <NUM> further includes the first hydraulic cylinder <NUM> (see <FIG>) including a rear end <NUM> pivotally connected to the back plate <NUM> of the milling attachment frame <NUM> at pivot pin <NUM>. A forward end <NUM> of hydraulic cylinder <NUM> is pivotally connected to the axially inner arm member <NUM> of first pivot arm <NUM> at pivot pin <NUM>.

The axially outer arm member <NUM> is connected to the first adjustable side plate <NUM> at the previously mentioned connection <NUM>.

The first pivot arm <NUM> pivots relative to milling attachment frame <NUM> about pivot axis <NUM>. As the pivot arm <NUM> pivots the interaction of connector <NUM> with the first adjustable side plate <NUM> raises or lowers the first adjustable side plate <NUM>. The forward end <NUM> of hydraulic cylinder <NUM> is retracted to raise the first adjustable side plate <NUM> and extended to lower the first adjustable side plate <NUM>.

The second actuator <NUM> is constructed substantially the same as the first actuator <NUM>, including a hydraulic cylinder and a pivot arm, like the hydraulic cylinder <NUM> and the pivot arm <NUM>.

As can be appreciated from <FIG> and <FIG> the hydraulic cylinders such as <NUM> of the first and second actuators <NUM> and <NUM> may be oriented primarily horizontally which will be understood to be within plus or minus ten degrees of horizontal when the milling attachment <NUM> is resting on a horizontal surface <NUM>.

It will be appreciated that in addition to raising and lowering the milling attachment frame <NUM> relative to the ground surface <NUM> to adjust the milling depth <NUM> of milling drum <NUM>, the adjustable side plates <NUM> and <NUM> in combination with the first and second frame side walls <NUM> and <NUM> function to enclose the milling drum <NUM> so as to capture the milled material created by the operation of the milling drum. Similarly, the movable front cover portion <NUM> can tilt up and down to enclose the front of the milling drum housing <NUM>.

In prior art milling attachments such tiltable front cover portions typically operated just by the force of gravity pushing them down and engagement with the ground surface <NUM> pushing them up. The present disclosure provides an improved arrangement whereby the first actuator <NUM> is connected to the movable front cover portion <NUM> by a first actuator extension <NUM> configured such that the movable front cover portion <NUM> is raised or lowered when the first adjustable side plate <NUM> is raised or lowered relative to the milling attachment frame <NUM>. Similarly, the second actuator <NUM> is connected to the movable front cover portion <NUM> by a second actuator extension <NUM>.

The first and second actuator extensions <NUM> and <NUM> may be in the form of cables <NUM> and <NUM> connected between the pivotable front cover portion <NUM> and the forward ends <NUM> of their respective actuator hydraulic cylinders such as <NUM>. The cables <NUM> and <NUM> are configured such that when the forward end <NUM> of the hydraulic cylinder <NUM> is retracted the cable pivots the front cover portion <NUM> upwards. In other embodiments the actuator extensions <NUM> and <NUM> may take other forms, such as for example linkages connecting the actuators to the front cover portion <NUM>.

First hydraulic cylinder <NUM> is shown in <FIG> in a fully retracted position corresponding to the uppermost raised position of the first adjustable side plate <NUM> seen in <FIG> and corresponding to the upwardmost pivoted position of the pivotable front cover portion <NUM>. First hydraulic cylinder <NUM> is shown in <FIG> and <FIG> in a fully extended position corresponding to the lowermost position of the first adjustable side plate <NUM> seen in <FIG>, and corresponding to the lowermost pivoted position of the pivotable front cover portion <NUM> as seen in <FIG>. The upper and lower pivotal positions of the pivotable front cover portion <NUM> are schematically represented in <FIG> and <FIG>. It is noted that no attempt has been made to depict the movement of the pivotal front cover portion <NUM> between <FIG> and <FIG>.

As can best be seen in <FIG> the frame top <NUM> includes a rounded forward top portion <NUM> curving forwardly and downwardly toward the ground surface <NUM>. The cables <NUM> and <NUM> may slide upon the rounded forward top portion <NUM> of the frame top <NUM> when the movable front cover portion <NUM> is raised or lowered. The cables <NUM> and <NUM> may be further guided by protrusions <NUM> and <NUM> see in <FIG>.

As previously noted, the actuators <NUM> and <NUM> are independently operable. Thus, if either hydraulic cylinder such as <NUM> is retracted the pivotable front cover portion <NUM> will be pulled upward. When the actuator or actuators that have pulled the pivoted front cover portion <NUM> upward are extended, then the pivoted front cover portion will be lowered by gravitational force.

As seen in <FIG> lower ends of the first and second cables <NUM> and <NUM> are connected to the pivoted front cover portion <NUM> at spaced connections <NUM> and <NUM> separated by a distance <NUM> greater than one-half of a distance <NUM> separating the first and second frame side walls <NUM> and <NUM>. The upper ends of the cables <NUM> and <NUM> are shown as connected to clips <NUM> and <NUM>, respectively, which are connected to the pivot pins such as <NUM> which connect the forward ends <NUM> of cylinders <NUM> to the respective pivot arms <NUM>. In another embodiment the cables <NUM> and <NUM> could be connected to other moving parts of the actuators <NUM> and <NUM>, such as being directly connected to the pivot arms such as <NUM>.

By the arrangement described above the actuators <NUM> and <NUM> of the present disclosure provide a dual function to control the raising and lowering of both the side plates <NUM>, <NUM> and of the pivoted front cover portion <NUM>. As compared to the prior art gravity operated front cover portions, this reduces wear and tear on the front cover portion <NUM> and provides for a more reliable sealing of the milling drum housing <NUM>.

It is noted that in another embodiment, not shown, the kinematic arrangement of the hydraulic cylinders with the side plates could be reversed so that the cylinders are extended to raise the side plates and retracted to lower the side plates. In such an arrangement a redirecting device such as a deflection pulley could be used to reverse the operation of the cables <NUM> and <NUM> so that the extension of the cylinders would raise the movable front cover portion <NUM> and the retraction of the cylinders would lower the movable front cover portion <NUM>.

As described above with reference to <FIG> and <FIG>, the milling attachment <NUM> may be mounted with a pivotal mount <NUM> so that the milling attachment <NUM> may be tilted to the right or left about a tilt axis <NUM> relative to the work machine <NUM>. This tilting action is controlled by the hydraulic tilt cylinder <NUM> best seen in <FIG>.

As schematically shown in <FIG>, a hydraulic circuit <NUM> may be provided for operation and control of the hydraulic tilt cylinder <NUM>. The hydraulic tilt cylinder <NUM> may be a double acting cylinder which can push or pull to tilt the milling attachment <NUM> to the right or left, respectively. The hydraulic tilt cylinder <NUM> is powered by hydraulic fluid provided through two hydraulic lines <NUM> and <NUM> which may operate as fluid supply and return lines.

Flow of hydraulic fluid to and from the lines <NUM> and <NUM> is controlled by a valve <NUM> which has at least three positions.

In a first position <NUM> hydraulic fluid from sump <NUM> is provided under pressure by pump <NUM> to the first hydraulic line <NUM> to retract the hydraulic tilt cylinder <NUM>. Simultaneously return fluid passes through the second line <NUM> to return line <NUM> and to the sump <NUM>.

In a second position <NUM> hydraulic fluid from sump <NUM> is provided under pressure by pump <NUM> to the second hydraulic line <NUM> to extend the hydraulic tilt cylinder <NUM>. Simultaneously return fluid passes through the first line <NUM> to return line <NUM> and to the sump <NUM>.

The first and second positions <NUM> and <NUM> may be referred to as active tilt modes wherein hydraulic fluid under pressure is applied to the hydraulic tilt cylinder <NUM> to tilt the milling attachment <NUM>.

In a third position <NUM> the two hydraulic lines <NUM> and <NUM> are connected together in a closed loop and the hydraulic cylinder <NUM> is free to float in either direction under the forces imposed by the milling attachment <NUM>. The third position <NUM> may be referred to as a floating mode in which the hydraulic tilt cylinder <NUM> does not apply any tilting force to the milling attachment <NUM>.

By the present disclosure a tilt control <NUM> is placed within the operator's station <NUM> so that the tilt control <NUM> may be conveniently manipulated by the operator to switch the hydraulic circuit <NUM> between the active tilt mode <NUM> or <NUM> and the floating mode <NUM> during the milling operation. The tilt control <NUM> may be provided in various embodiments.

In one embodiment the valve <NUM> may be an electro-mechanical control valve and the tilt control <NUM> may be a switch, knob or other input to an electrical controller which sends a control signal via control line <NUM> to the valve <NUM> to switch the position of the valve <NUM>.

In another embodiment the valve <NUM> may be a manually operated valve and the valve <NUM> itself may be placed in the operator's station <NUM>. This will require the hydraulic lines <NUM> and <NUM> to be run into the operator's station <NUM>. Then the tilt control <NUM> may be embodied as a handle <NUM> for manual operation of the valve <NUM> located within the operator's station <NUM>.

In one method of using the tilt control <NUM> the operator may start a milling operation with both adjustable side plates <NUM> and <NUM> engaging an asphalt surface <NUM> which is to be milled. The milling operation may start with the valve <NUM> in the free-floating position <NUM>. The milling operation may continue until one of the adjustable side plates <NUM> or <NUM> reaches a different surface, such as for example a soft shoulder of the street. At that point the operator may engage the tilt control <NUM> to switch the valve <NUM> to either position <NUM> or <NUM> to actively tilt the milling attachment <NUM> relative to work machine <NUM> to prevent the one side plate from digging into the soft ground surface. With the present system this can be performed without interrupting the milling operation.

<FIG> shows an alternative embodiment of a hydraulic circuit for operation and control of the hydraulic tilt cylinder <NUM>. The hydraulic circuit of <FIG> is designated by the number <NUM>. The hydraulic tilt cylinder <NUM> is powered by hydraulic fluid provided through two hydraulic lines <NUM> and <NUM> which may operate as fluid supply and return lines.

A master control valve <NUM> controls flow of hydraulic fluid from pump <NUM> and return of hydraulic fluid to tank <NUM>. Master control valve <NUM> is a three position valve and it controls flow to and from other valves associated with each hydraulically powered component.

The tilt cylinder <NUM> has associated there with two tilt control valves <NUM> and <NUM>. Each of the tilt control valves <NUM> and <NUM> is a two-position valve that either permits or blocks flow from the master control valve <NUM> to the hydraulic lines <NUM> and <NUM> and thus to the two pressure chambers <NUM> and <NUM> of the tilt cylinder <NUM> to tilt the milling attachment <NUM> to the right or left.

The master control valve <NUM> has two active positions <NUM> and <NUM> which can direct pressurized hydraulic fluid to either of the intermediate lines <NUM> or <NUM>. A third position <NUM> is a neutral position which communicates both lines <NUM> and <NUM> to the tank <NUM>. Thus, with the master control valve in either position <NUM> or <NUM> and with the tilt control valves <NUM> and <NUM> in their open positions the milling attachment <NUM> is actively tilted to the right or left.

With the embodiment of <FIG> a floating mode for the tilt cylinder <NUM> is provided by two float control valves <NUM> and <NUM>. Each of the float control valves <NUM> and <NUM> is a two-position valve that either permits or blocks flow from the hydraulic lines <NUM> and <NUM> back to the tank <NUM>. When the tilt control valves <NUM> and <NUM> are in their closed positions and the float control valves <NUM> and <NUM> are in their open positions the hydraulic lines <NUM> and <NUM> and thus the pressure chambers <NUM> and <NUM> of tilt cylinder <NUM> are open to a return line <NUM> and to each other. In this arrangement the hydraulic cylinder <NUM> is free to float in either direction under the forces imposed by the milling attachment <NUM>. This arrangement may be referred to as a floating mode in which the hydraulic tilt cylinder <NUM> does not apply any tilting force to the milling attachment <NUM>.

The tilt control <NUM> is again placed within the operator's station <NUM> so that the tilt control <NUM> may be conveniently manipulated by the operator to switch the hydraulic circuit <NUM> between the active tilt mode and the floating mode during the milling operation. The tilt control <NUM> may be a switch, knob or other input to an electrical controller <NUM> which sends control signals via control lines <NUM>, <NUM> to the valves <NUM>, <NUM>, <NUM>, <NUM> and <NUM>.

Claim 1:
A milling attachment (<NUM>) for a work machine, comprising:
a frame including first and second frame side walls (<NUM>, <NUM>);
a milling drum (<NUM>) including first and second drum mounting flanges (<NUM>, <NUM>);
a motor mounting plate (<NUM>) removably mounted on the second frame side wall (<NUM>);
a first drive motor (<NUM>) mounted on the first frame side wall (<NUM>) and including a drive end (<NUM>) connected to the first drum mounting flange (<NUM>) by a plurality of threaded fasteners (<NUM>); and
a second drive motor (<NUM>) mounted on the motor mounting plate (<NUM>) and connected to the second drum mounting flange (<NUM>) by a stab-in non-threaded connector (<NUM>).