A mobile milling machine comprising a drum access mechanism

Abstract: A mobile milling machine (1) for milling a road surface includes a floating mould board (20) for directing milled material onto a loading device (30) positioned behind the machine. The mould board has fixed thereto a holder (32) for the loading device. The loading device (30) is pivotable side-to-side about an upright axis, with respect to the holder (32). The mould board (20), the holder (32) and the loading device (30) are moveable a limited distance between a top and bottom stop position and pivotable about a horizontal axis (60) at the top stop position, to expose a milling roller (10) for repairs. When the machine is in operation, the mould board (20), the holder (32) and the loading device (30) are hydraulically supported (62,70) to permit the mould board (20) to float along the milled surface in grazing contact.

Description: This invention relates generally to mobile road milling machines, and more particularly to structures that support a loading device positioned behind the machine to collect milled material. A compact milling machine for milling off damaged road surfaces is disclosed in GB-A-2 154 266. The milling machine comprises a loading device which can be swung out of its milling position after the milling process is complete and thus provides access to the milling roller. A hydraulic positioning cylinder is provided for the swivelling action, by means of which the loading device together with its holder can be raised in a swivelling manner about the axis of bearings arranged at the end of the milling machine. On the holder of the loading device there is provided a vertically located equalizing plate which is arranged in slotted holes over the holder and can consequently be adapted to different milling depths. It is an object of the present invention to provide structures that support a loading device positioned behind the machine to collect milled material, while permitting easy access to the milling device for repairs. This object is solved, according to the invention, with the features of claim 1. For a better understanding of the invention and to show how the same may be carried into effect, reference will now be made, by way of example, to the accompanying drawings, in which:- Fig. 1 is a schematic isometric view showing a rear portion of a mobile road milling machine, with parts removed, showing a milling drum, mould board and holder, with the mould board in a vertical position; Fig. 2 is a view similar to Fig. 1, with the mould board pivoted upwardly to expose the milling roller; Fig. 3 is a side elevation view, showing the mould board in the vertical position; Fig. 4 is a view similar to Fig. 3, showing the mould board pivoted upwardly; Fig. 5 is a plan view of Fig. 3; and Fig. 6 is an example of hydraulic circuit for actuating the mould board. Referring to Fig. 1, there is shown a mobile milling machine 1 having a chassis 3 mounted thereon, the chassis 3 having a front portion 5 and a rear portion 7. As is well known, the machine is provided with a drive motor and steering mechanism (not shown). A milling roller 10 is rotatably mounted transversely on the chassis 3 within a roller housing 12. The roller 10 is equipped with cutter teeth (not shown) and is powered for rotation about an axle by any well-known means (not shown). The roller housing 12 is formed by a left chassis rail 14 that extends lengthwise along the machine 1, a right chassis rail 16 that extends parallel to the rail 14, a top frame member 18 of the chassis 3 extending therebetween, and a frontward portion 17 of the chassis 3 (Fig. 3). A rearward opening 19 (Fig. 2) in the housing 12 is closed by a mould board 20. The mould board 20 is mounted transversely of the chassis 3 in a substantially vertical position, adjacent the roller 12. The mould board comprises a lower edge 23 for contacting a milled road surface 22, an upper edge 24 and an aperture 26 therethrough for directing milled material therethrough. A loading device 30, preferably a conveyor, is positioned rearwardly of the mould board 20, and is carried by chassis mould board 20, as described hereinafter. A holder 32 (Fig. 1) for the loading device 30 is fixed to the mould board 20. The holder 32 forms an inverted U-shaped platform 34 (Fig. 2) fixed to the mould board 20, as by welding, and extending outwardly therefrom. The holder 32 and mould board 20 form a unitary structure that are fixed in relation to each other. The platform 34 has a pair of upright side members 36, 38 fixed to the mould board 20, and spaced apart from each other, one side member 36 on one lateral side of the opening 26 and the other side member on the opposite lateral side of the opening 26. A top member 40 is positioned above the opening 26 and is fixed to the side members 36, 38, extending therebetween. The loading device 30 is coupled to the holder 32 for side-to-side pivoting about an upright axis 42. The coupling is accomplished by an inverted U-shaped yoke 44 spanning the platform 34. The yoke 44 has a pair of downwardly extending arms 46, 48 spaced apart from each other, one arm 46 being positioned adjacent to the side member 36, and the other arm 48 being positioned adjacent to the other side member 38. A top arm 50 extends between the arms 46, 48 and connects them together. The top arm 50 is pivotally connected by any well known means, such as a pivot pin, to the top member 40 of the holder 32. Yoke 44 is thereby pivotable side-to-side with respect to the holder 32, about the axis 42. The loading device 30 is pivotally connected to the bottom ends of the arms 46, 48. The loading device 30 can be supported by the chassis 3 by well known means, such as cables or a hydraulic cylinder and rod combination, that can be used to raise and lower the angle of the loading device 30. The mould board 20 is equipped with pivot pins 52, 54 at the extremity of the mould board 20 at the top edge 24. One pin 52, extends into a vertical slot 56 in the left chassis rail 14, and one pin 54 extends into a vertical slot 58 in the right chassis rail 16. The mould board 20 holder 32, and loading device 30 are moveable a limited distance (the length of the slots 56, 58) between a top stop position and a bottom stop position. When the pins 52, 54 reach the top stop position, vertical movement thereof stops, and the entire combination will pivot outwardly and upwardly, around a horizontal or transverse axis 60 through the pivot pins 52, 54 at the top edge 24. The actuator means for simultaneously raising the holder 32, mould board 20 and loading device 30 for the bottom stop position to the top stop position, and for thereafter simultaneously pivoting the entire combination about the axis 60 will now be described. A first hydraulic cylinder and rod combination 62 has a rod end 64 pivotally connected to the mould board 20 adjacent a first lateral side of the opening 26, and a cylinder end 66 pivotally connected to the chassis 3. A second hydraulic cylinder and rod combination 70 has a rod end 72 pivotally connected to the mould board 20 adjacent a second lateral side of the opening 26, and a cylinder end 74 pivotally connected to the chassis 3. Combinations 62, 70 extend upwardly parallel to each. Thus, it can be understood that movement of the rods 64, 72 will cause the mould board 20 and members connected thereto to move up and down in the slots 56, 58 and to pivot about the axis 60. In order to restrain the mould board movement to a vertical direction, locking devices 80, 82 are positioned on the mould board 20 at the lower extremity, adjacent the bottom edge 23. A description of one device will suffice because both devices are the same. A locking pin 84 is slidably positioned in a housing 86 fastened to the mould board 20. The pin 84 can be extended into an adjacent slot 88 in the adjacent chassis rail 14. The pin 84 is locked in place by a removable key 90 that extends through the housing 86 and blocks movement of the pin 84. With the pin 84 in the adjacent slot 88 the mould board 20 can only move vertically. Removal of the pin 84 from the slot 88 permits mould board 20 to pivot outwardly and upwardly. It should be apparent that, when the mould board 20 is in the operating condition, the combined weight of the loading device 30, the holder 32 and the yoke will cause the mould board 20 to move downward to contact the milled road surface. Too much weight on the mould board 20 will cause the machine to slow down, thereby reducing production. Therefore, a hydraulic actuator circuit is provided to give a limited upward support force acting through the cylinder and rod combinations 62, 70 on the aforesaid combination to permit the mould board 20 to float along the milled road surface in a grazing (barely touching) contact. Fig. 6 shows the hydraulic circuit. A three position valve 100 has a lifting position 102, a hold position 104 and a float position 106. When the valve 100 is switched into the hold position, three-way pilot valve 110 causes the cylinder/rod combinations 62, 70 to be held in their positions. When the valve 100 is switched into the lifting position, the three-way pilot valve 110 and flow divider 112 permit full pressure to be exerted on the rod end 64, 72 of each cylinder 62, 70, retracting the rods, to raise the mould board 22. When the valve 100 is switched to the float position, the three-way pilot valve 110 and flow divider 112 act as they did in the lift position, but reducing/relief valve 114 permits pressure to be exerted on the back end of the rods 64, 70, partially offset to the pressure on the rod ends, thereby causing the mould board 20 to float. The amount of pressure transmitted through the valve 114 can be manually adjusted by an adjustment knob 116, as is well known. Fig. 6 shows the port designations 1, 2, 3 for each valve 108, 110 and 114. Now referring to Fig. 5 the means for moving the loading member 30 side-to-side about the axis 42 will be described. A third hydraulic cylinder and rod combination 120 has a rod end 122 pivotally connected to one yoke arm 46, and cylinder end 124 pivotally connected to the mould board 20 adjacent the other yoke arm 48. Extension and retraction of the rod 122 moves the loading device 30 back and forth. Fig. 2 shows an alternative embodiment for the lower edge 23 of mould board 20. The lower edge 23 is formed by a laterally floating support bar 130 that is connected to the mould board 20, below the opening 26. The support bar 130 is connected, as by bolting, to the mould board 20 through laterally elongate slots 132, which permit the support bar 130 to float laterally, side-to-side, as the machine moves. When the machine moves around a curve in the road, lateral movement of the support bar 130 permits the mould board to more accurately track the path of the milling cutter 10, thereby improving the collection of milled material. A laterally floating support bar is preferred, but a non-floating support bar will work. The support bar 130 has a plurality of carbide wear blocks 140 removably connected thereto, along its entire lateral length. Each wear block 140 is connected, as by bolting, to the support bar 130 via apertures 142 therethrough. As the wear blocks 140 wear out, they can be quickly replaced. Whilst hydraulic cylinders are preferred, other power systems can work, such as pneumatic actuated cylinders or electrical linear actuator systems.

Claims: A mobile milling machine (1) for milling a road surface comprising: a chassis (3) having a front portion (5) and a rear portion (7); a milling roller (10) rotatably mounted transversely on said chassis within a roller housing (12); a mould board (20) mounted transversely on said chassis, adjacent to said milling roller and in a substantially vertical position, for directing milled material therethrough; a holder (32) for a loading device (30) fixed to said mould board (20); means (44) for coupling said holder (32) to said loading device (30), for pivoting said loading device with respect to said holder about an upright axis (42); characterized by said mould board (20) and said holder (32) being moveable a limited distance between a top stop position and a bottom stop position and pivotable at a mould board upper edge (24) about a substantially horizontal axis (60) at said top stop position, wherein said mould board (20) is moved downwards in its operating condition to contact the milled road surface; and by actuator means (62,70) for simultaneously raising said holder (32), said mould board (20) and said loading device (30) from said bottom stop position to that top stop position, and for thereafter simultaneously pivoting said holder, said mould board and said loading device about said horizontal axis (60), whereby said roller housing (12) is opened to permit access to said milling roller (10). A milling machine according to claim 1 and comprising a loading device (30). A milling machine according to claim 2, wherein said loading device (30) is positioned rearwardly of said mould board (20), which itself is located rearwardly of said milling roller (10). A milling machine according to claim 1, 2 or 3, wherein said mould board (20) has a lower edge (23) for contacting a road surface and an opening (26) for directing milled material therethrough. A milling machine according to claim 2 or 3, or according to claim 4 as appendant to claim 2, wherein, when said mould board (20) is in its operating condition, the combined weight of said holder (32), mould board (20) and loading device (30) causes said mould board (20) to move downwards to contact the milled road surface. A milling machine according to claim 2 or 3, or according to claim 4 or 5 as appendant to claim 2, wherein, when said mould board (20) is in its operating condition, said actuator means (62, 70) supplies a limited upward support force to said mould board (20), holder (32) and loading device (30) to permit said mould board to float along the milled road surface in a grazing contact therewith. A milling machine according to any one of the preceding claims, further comprising second actuator means (120, 124) for pivoting said loading device (30) with respect to said holder about said upright axis (42). A milling machine according to any one of the preceding claims, wherein said holder (32) forms an inverted U-shaped platform (34) fixed to said mould board (20), extending outwardly therefrom, said platform (34) having a pair of spaced, upright side members (36, 38) and a top member (40) extending therebetween. A milling machine according to claim 8, wherein said means for coupling said loading device (30) to said holder (32) comprises an inverted U-shaped yoke (44) spanning said platform (34), said yoke (44) having a pair of downwardly extending arms (46, 48) spaced apart from each other, each arm being positioned adjacent to one of said side members (36, 38) of said holder, and a top arm (50) extending therebetween, said top arm being pivotally connected at said upright axis (42) to said top member (40) for pivoting said yoke (44) with respect to said holder about said upright axis. A milling machine according to claim 9 as appendant to claim 2, wherein said loading device (30) is pivotally coupled to said yoke (44) at a bottom end of each of said arms (46, 48). A milling machine according to any one of the preceding claims wherein said actuator means (62, 70) comprises: a first hydraulic cylinder and rod combination (62), having a rod end (64) pivotally connected to one lateral side of said mould board (20) and a cylinder end (66) pivotally connected to said chassis (3); a second hydraulic cylinder and rod combination (70), having a rod end (72) pivotally connected to the other lateral side of said mould board (20) and a cylinder end (74) pivotally connected to said chassis (3); and hydraulic circuit means for actuating said first and second hydraulic cylinder and rod combinations. A milling machine according to claim 11 as appendant to claims 7 and 9, wherein said second actuator means comprises a third hydraulic cylinder and rod combination (120), having a rod end (122) pivotally connected to one of said yoke arms (46) and a cylinder end (124) pivotally connected to said mould board adjacent the other of said yoke arms (48). A milling machine according to any one of the preceding claims and further comprising locking means (80, 82) for permitting said mould board to move between said top and bottom stop positions, while not permitting said mould board to pivot at the upper edge (24) of said mould board at said top stop position. A milling machine according to any one of the preceding claims, wherein the lower edge (23) of said mould board (20) is formed by a laterally floating support bar (130) connected to said mould board. A milling machine according to claim 14, wherein said support bar (130) has removably connected thereto a plurality of wear blocks (140) for contacting the road surface.

Inventors: LYONS SCOTT F, LYONS, SCOTT F.
Applicants: WIRTGEN GMBH
Application year: 1995
Main classification: E01C23
IPC codes: E01C23