Claims:We claim:

1. A scraper gate mechanism (50) for a scraper gate (60) of a milling unit (100) of a milling machine, the scraper gate mechanism comprising (50):
a hinged plate (10) fixed to a housing (70) of the milling unit (100) by a first hinge (4) and a second hinge (6), the second hinge (6) being detachably connected to one side (65) of the housing (70), the hinged plate (10) having a pair of support blocks (8) fixed thereon, each support block (8) having a thorough central opening;
a sliding plate (30) having a pair of blocks (24) fixed thereon, each block (24) having a central opening;
a pair of guide rods (40) having a first end (34) and a second end (38), the first end (34) of each guide rod (40) fixed in the central opening of the blocks (24), the second end (38) of each guide rod (40) capable of sliding through the central openings of the pair of support blocks (8); and
an actuator (20) connected between the hinged plate (10) and the sliding plate (30), the actuator (20) capable of pulling up the sliding plate (30) to adjust height thereof to partially open the scraper gate with the help of the pair of guide rods (40),
wherein, the scraper gate (60) is fully opened by detaching the second hinge (6) from the side (65) of the housing (70).

2. The scraper gate mechanism (50) as claimed in claim 1, wherein the scraper gate (60) is capable of rotating with respect to the first hinge (4) freely or by means of an actuator mounted on the hinged plate (10) thereby allowing the scraper gate (60) to open fully and independently of an engine power supply.

3. The scraper gate mechanism (50) as claimed in claim 1, wherein the actuator (20) is a linear actuator and length of the actuator (20) is adjustable as per the surface to be milled at various depths by the milling machine.

4. The scraper gate mechanism (50) as claimed in claim 1, wherein the actuator (20) is adapted to restrict/control sliding of the sliding plate (30) using any one of a hydraulic pressure, electric means and pneumatic means.
, Description:SCRAPER GATE MECHANISM

Field of the invention

The present invention generally relates to construction equipment and more particularly, to a scraper gate mechanism for a milling machine.

Background of the invention

A mobile milling machine for milling a road surface consists of a milling drum which mills off the pavement of road. The milled off pavement material is transferred to a mobile vessel cum carrier via conveyor belts. In order to transfer the milled material to the conveyors, the milled material is guided and enclosed within housing called drum housing. The milling machine changes milling depth thereof between certain values by adjusting the drum depth. For this purpose, the drum housing has height adjustable walls. The wall, which is located on backside of the machine when viewed from machine travel direction, scrapes off un-milled pavement material, which is supposed to be milled by the milling drum. This wall is called as a scraper gate. The milled material is collected and swiped with the scraper gate in order to give thoroughly clean milled surface after milling. Many times while milling with medium width drum machines, operator uses the scraper gate to ensure edge to edge cutting from previous cut by sensing uncut kerbs with the help of a scraper gate side edge.

The scraper gate is also used to access drum picks for service and to sweep the accumulated material for clear milled surface. Generally, milling drum tools or picks need to be changed at certain time intervals due to wear. In order to access the picks mounted on the drum, the scraper gate needs to be fully opened. Hence, the scraper gate is designed in such a way that it is able to open fully, can be adjusted at variable height and rigidly held to scrape off and sweep the milled material as well.
In the existing machines, scraper gate can be opened to access drum, only when an engine is working and a hydraulic system is pressurized. Due to large sliding door, the weight of the scraper gate assembly is high and the hydraulic cylinder stroke length is higher. In some machines, multiple cylinders are used for opening and height adjustment of the scraper gate.

In some machines, the scraper gate mechanism is designed in such a way that an entire door or gate slides which leads to occupy more space and half of the length above the chassis. Further, such mechanisms require larger cylinder stroke since entire door has to be opened by sliding. Also the entire machine layout is constrained to accommodate the door whose length is huge. Mounting of long stroke cylinder requires heavier assembly to hold cylinder rigidly at raised height.
Accordingly, there exists a need to provide a scraper gate mechanism for a milling machine that overcomes the above-mentioned drawbacks in the prior art.

Objects of the invention

The primary object of the present invention is to allow access to milling cutter tooth/picks when an engine is switched off without a hydraulic power.

Another object of the present invention is to allow partial opening of a scraper gate that result in a lesser stroke length of an actuator and hence better space utilization and lesser costs.

Summary of the invention

Accordingly, the present invention provides a scraper gate mechanism (hereinafter “the mechanism”) for a scraper gate of a milling unit of a milling machine. The mechanism comprises a hinged plate, an actuator, a sliding plate and a pair of guide rods.
The hinged plate is fixed to a housing of the milling unit by a first hinge and a second hinge. The scraper gate is capable of rotating with respect to the first hinge freely or by means of an actuator mounted on the hinged plate thereby allowing the scraper gate to open fully and independently of an engine power supply. The second hinge is detachably connected to one side of the housing. The hinged plate includes a pair of support blocks fixed thereon. Each support block includes a thorough central opening.

The sliding plate includes a pair of blocks fixed thereon. Each block includes a central opening. The pair of guide rods includes a first end and a second end. The first end of each guide rod is fixed in the central openings of the pair of blocks. The second end of each guide rod is capable of sliding through the central openings of the pair of support blocks.

The actuator is connected between the hinged plate and the sliding plate. The actuator is a linear actuator and length of the actuator is adjustable as per the surface to be milled at various depths by the milling machine. The actuator is adapted to restrict/control sliding of the sliding plate using any one of a hydraulic pressure, electric means and pneumatic means. The actuator pulls up the sliding plate to adjust height thereof to partially open the scraper gate with the help of the pair of guide rods. The scraper gate is fully opened by detaching the second hinge from the side of the housing.

Brief description of the drawings

The objects and advantages of the present invention will become apparent when the disclosure is read in conjunction with the following figures, wherein
Figure 1 is a perspective view of a milling unit showing a scraper gate mechanism, in accordance with the present invention;

Figure 2 is a rear view of the milling unit showing the scraper gate mechanism, in accordance with the present invention;

Figure 3 shows a scraper gate of the milling unit when a sliding plate is in raised position, in accordance with the present invention; and

Figure 4 shows a scraper gate open position, in accordance with the present invention.

Detailed description of the invention

The foregoing objects of the invention are accomplished and the problems and shortcomings associated with prior art techniques and approaches are overcome by the present invention described in the present embodiments.

In general aspect, the present invention provides a scraper gate mechanism for a milling machine. The scraper gate mechanism is mounted on a housing of a milling cutter by means of two hinges. The scraper gate mechanism allows access to the tool picks when an engine is switched off without the hydraulic power. The mechanism allows partial opening of a scraper gate that result in a lesser stroke length of a cylinder/actuator and hence better space utilization and lesser costs.

The present invention is illustrated with reference to the accompanying drawings, throughout which reference numbers indicate corresponding parts in the various figures. These reference numbers are shown in bracket in the following description.

Referring to figures 1-4, a scraper gate mechanism (50) (hereinafter “the mechanism (50)”) for a milling machine in accordance with the present invention is shown. Specifically, the mechanism (50) is applicable to a scraper gate/access door (60) of a milling unit (100) for a cold milling machine and for such machines used for road construction or maintenance.
The mechanism (50) comprises a hinged plate (10), an actuator (20), a sliding plate (30) and a pair of guide rods (40).

The hinged plate (10) is fixed to a housing (70) of the milling unit (100) by a first hinge (4) and a second hinge (6). Specifically, the hinged plate (10) is connected to sides (65) of the housing (70) through the hinges (4, 6). The scraper gate (60) is capable of rotating with respect to the first hinge (4) freely or by means of an actuator (not shown) mounted on the hinged plate (10) thereby allowing the scraper gate (60) to open fully and independently of an engine power supply for changing and servicing the milling unit (100) and a plurality of milling cutter picks/tooth (75) (hereinafter, “the picks (75)) mounted on a cutter drum (80) of the milling unit (100). In an embodiment, the second hinge (6) is detachably connected to the side (65) of the housing (70) of the milling unit (100). However, it is understood here that any one or both the hinges (4 and/or 6) may be detachably attached to the housing (70) of the milling unit (100) as per the design of the milling machine in other alternative embodiments of the mechanism (50). The hinged plate (10) includes a pair of support blocks (8) fixed thereon by welding. Each support block (8) includes a thorough central opening (not numbered).

The scraper gate (60) rotates about a hinge axis (2) when the detachable hinge (6) is not assembled. The scraper gate (60) is opened and closed freely by just detaching one of the hinges (4 or 6). In accordance with the present invention, being hinge-mounted the scraper gate (60) is easily opened even when the engine is switched off. Figures 1 and 2 shows the scraper gate rigid holding where both the hinges (4, 6) are in attached condition and the scraper gate (60) is in working mode when milling zero depth. While milling at various depths, the scraper gate (60) is in raised position as shown in figure 3. Figure 4 shows an open condition of the scraper gate (60) where the hinge (6) is detached. The scraper gate (60) is opened for maintenance or service of the cutter drum (80) and the picks (75).

The actuator (20) is connected between the hinged plate (10) and the sliding plate (30). In an embodiment, the actuator (20) is a linear actuator and length of the actuator (20) is adjustable as per the surface to be milled at various depths by the milling machine. The actuator (20) pulls up the sliding plate (30) to adjust height thereof to partially open the scraper gate (60) with help of the pair of guide roads (40). The actuator (20) is adapted to restrict/control sliding of the sliding plate (30) using any one of a hydraulic pressure, electric means and pneumatic means.

The sliding plate (30) includes a pair of blocks (24) fixed thereon. Each block (24) includes a central opening (not numbered). As a result of connections between the sliding plate (30) and the hinged plate (10) whenever the actuator (20) actuates, the sliding plate (30) slides with respect to the hinged plate (10).

The pair of guide roads (40) includes a first end (34) and a second end (38). The first end (34) of each guide rod (40) is fixed in the central opening of the blocks (24). The second end (38) of each guide rod (40) is capable of sliding through the central openings of the support blocks (8) that are mounted on the hinged plate (10).

Again referring to figures 1-4, in an operation, when the milling machine is in action, the scraper gate (60) is closed and rigidly held by the hinge (6) mounted on other end of hinged plate (10). On rotation of the cutter drum (80), the scraper gate (60) clears off un-milled material and also sweeps collected milled material towards the machine advance direction to leave behind clean milled surface. In particular working condition when the milling machine is milling the surface, the scraper gate (60) needs to be held rigidly. Because the scraper gate (60) scrapes off un-milled pavement material and gets subjected to loads. Hence, the scraper gate (60) is held rigidly with the housing (70) of the milling unit (100) as illustrated in figure 1.

While taking an initial cut, the scraper gate (60) is raised equally by required depth of cut by the sliding plate (30). The sliding plate (30) slides upwards with help of the actuator (20) and is guided by the pair of guide rods (40). The pair of guide rods (40) mounted on the blocks (24) slides with respect to the pair of support blocks (8). The scraper gate (60) is rigidly held by the hinges (4, 6) that restrict all movements of the scraper gate (60) except sliding of the sliding plate (30). The actuator (20) restricts/controls sliding of the sliding plate (30) using any one of a hydraulic pressure, electric means and pneumatic means. Particular milling/mining machines mills surfaces at various depths by means of the cutter drum (80). The cutter drum (80) penetrates at various depths and the scraper gate (60) adjusts height thereof as illustrated in figure 3 to carry out milling at various depths. This rigidly mounted scraper gate (60) accurately tracks the path of the milling unit (100) thereby improving the collection of milled material and gives clean milled surface.

In accordance with the present invention, the scraper gate (60) is fully opened by removing the one of the hinge (6) from the side (65) of the housing (70) and partially opened by adjusting the height of the sliding plate (30) that is controlled and guided by the actuator (20) and the pair of guide rods (40). Hence, the scraper gate (60) does not require special mountings rose above a chassis level. As the hydraulic system is not required to fully open the scraper gate (60), the tool changing is done even when the engine is switched off. During rear right wheel swing process, the wheel is not in contact with a ground at that time the scraper gate (60) helps to keep machine stable. Additionally, for full access of the cutter drum (80), the actuator (20) is used that assists the manual effort required to open the scraper gate (60) or completely replace manual effort to open the scraper gate (60).

In accordance with the present invention, the scraper gate (60) is fully opened by detaching the second hinge (6) from the side (65) of the housing (70) and partially opened by sliding, so stroke length of the actuator (20) is reduced. To hold the scraper gate (60) in an accurate vertical sliding orientation, the pair of guide rods (40) is used that reduces number of actuators/cylinders to one. Due to partial opening of the scraper gate (60) overall size and weight of the mechanism (50) is also reduced.

Advantages of the invention

1. The mechanism (50) allows access to the milling cutter tooth /picks (75) when the engine is switched off without the hydraulic power.
2. The mechanism (50) allows partial opening of the scraper gate (60) that result in a lesser stroke length of the actuator (20) and hence better space utilization and lesser costs.
3. The mechanism (50 utilizes only one actuator that gives simplicity to design by reducing number of parts.
4. As the hinge axis (2) is vertical and the scraper gate (60) opens manually threat of injury is not present.
5. The mechanism (50) allows maximum opening of the scraper gate (60) by detaching one of the hinges (4 or 6) and by rotating the scraper gate (60) with respect to the vertical axis.

The foregoing descriptions of specific embodiments of the present invention have been presented for purposes of illustration and description. They are not intended to be exhaustive or to limit the present invention to the precise forms disclosed, and obviously many modifications and variations are possible in light of the above teaching. The embodiments were chosen and described in order to best explain the principles of the present invention and its practical application, and to thereby enable others skilled in the art to best utilize the present invention and various embodiments with various modifications as are suited to the particular use contemplated. It is understood that various omissions and substitutions of equivalents are contemplated as circumstances may suggest or render expedient, but such omissions and substitutions are intended to cover the application or implementation without departing from the scope of the claims of the present in