DESC:FIELD OF THE INVENTION:
The present invention relates to an apparatus for levelling for paving machine. More particularly, the present invention relates to a self-propelled apparatus for surface levelling machine.

BACKGROUND OF THE INVENTION:
The placement of concrete for roadways and highways has evolved over the years. Initially concrete roadways were placed much like any other slab, with the use of static forms and hand manipulated finishing tools. Eventually, machines were developed to assist in the distribution of the concrete. Such devices usually employ a set of sliding, edge forms that assist in forming the roadway. These slip form pavers also employ integral trowelling or screening devices to smooth the surface of the concrete. Typically, such conventional pavers use concrete of relatively low slump. As will be appreciated by those skilled in the art, low slump concrete is necessary in highway construction. First, the placed concrete can maintain its shape after the forms associated with the slip form paver move out of contact with the plastic concrete. The cured strength of Portland cement concrete used in highway construction is approximately 4,000 PSI. Conversely, in polymer concrete, the strength is approximately 8000-10,000 PSI, and polymer concrete exhibits a high slump.

Important parts of levelling machine are the frames of machine, which must be set perpendicular to the rail or form, the machine travels on. Initially by using a levelling instruments/Theodolite or water tube, adjust the frame of the machine up or down with the use of the grade jacks until all four corners of the machine are set equal distance above the rail or form. Rail level and alignment should be perfect at both sides; otherwise, it will affect finish uniform thickness. In doing so there are chances to remain manual error, which can result in improper finishes or levels. Further, while paving machine moves, the level can be disturbed frequently, which will further affect level of concrete frequently. Therefore, the frame of machine should remain in required level throughout the length.

The US patent discloses US3285148A a paving machine having hydraulic system for operating levelling arm wherein the pendulum and grid sensor are connected with a control means or cubicle for delivering electrical signals thereto. Amplified signals are transmitted from the control cubicle to solenoid valves and to hydraulic cylinders, which vertically shift the transverse pivot axes of the draft arms in order to produce a mat having a desired transverse slope.

The US patent US2043413 discloses a road-building machine for form grading and sub-grading. It is designed to more effectively excavate (than is possible with machines now in use) a smooth continuous grade on which forms may be placed or pavement laid. The present invention excavates trenches. There is a pair of cutting augers mounted in vertical position and set to rotate on their longitudinal axes, one rotating clockwise and the other rotating counter-clockwise, which will cut and excavate the earth for grading purposes. There is an apron with propeller mounted for removing excavated materials from the path of excavation. There is a provision for raising and lowering device to maintain the excavating parts on the predetermined grade. The device travels along a natural guideline or form and Warns the operator to raise or lower the excavating parts as contact is made by the guiding device against the guiding line or form and flashes a red or green signal and rings a bell for each signal for high or low grade.

The US patent US2489196 discloses a device having structure, which can be readily adjusted for use in connection with different types of heads or different conditions of terrain. The device maintains the depth of cut of the digger head in the ditch at a predetermined level and to accomplish this purpose the gauge structure is necessarily maintained on the digger head. The gauge structure includes a main U-shaped frame having parallel arms pivotally supported, which is at the axis of the drive for the endless digger mechanism. The projecting arm is in the form of a round straight rod, the axis of which is parallel to the axis of supporting arms.

The US patent US2601277A discloses an improvement in road machines, and the principal object is to provide a machine of this class, which may be advantageously applied in construction operations relative to road subgrades, base courses, surface courses and other work of similar nature such as tel-racing, levelling, compacting and miscellaneous construction of this nature.

The US patent US2720716A discloses an earth-working implement includes generally an extremely elongated, intermediately articulated frame assembly having a vertically adjustable scraper suspended therefrom intermediate its ends. The ends of the frame assembly being carried by wheels and for the accomplishment of accurate levelling as the implement traverses uneven ground. It is requisite that the scraper be adjusted up or down in order to maintain its cutting edge at a point lying in a straight line taken between the points of contact with the ground of said end wheels.

The US patent US2851799A discloses a device with provision of a gauge, which is used with facility for determining the height or depth of one element of its structure above or below a cooperating sensing element. There is an improved appliance for determining vertical heights and depths, such as can be utilized in connection with such equipment as mechanical ditch diggers for accurately maintaining the grade of cut. The same can also be used for ascertaining vertical heights of a slanting bore or hole, that is, the distance from the bottom of the bore or hole perpendicularly to some designated location there above. There is a provision of a gauge for designating a vertical distance differential, between certain points or locations and which can be utilized in connection with the operation of some accessory mechanism.

The US patent US2922345A discloses an apparatus for automatically producing a level surface, which is levelled in accordance with a predetermined level established in continuous fixed relation with the prescribed grade of roads and the like. The invention comprehends an apparatus having a levelling member for producing a level surface in the bed of a road and the like and in the material employed-in the construction thereof and which levelling member is movable in accordance with a predetermined guide level established by the requirement of the grade of the road to automatically vary the elevation thereof.
The US patent US3675229A discloses a sensing device and system for controlling the horizontal and/or vertical position of a steerable, vertically adjustable road-building machine. The device including a movable dial with exposed contacts about its periphery, which make connection with fixed contacts upon movement thereof in response to relative movement of the machine horizontally or vertically to a pre-set line to operate electrically a power means to restore the machine to a desired position. The system affords the operation of a signal if any abnormal movement is sensed as may happen if the pre-set line ends or breaks and the electrical switching is bypassed which would normally perform a control function to adjust for the relative movement.

SUMMARY OF THE INVENTION:

The principal object of the present invention is to provide an automatic pitch control apparatus for paving machine characterised by movable legs attached to main frame of the said apparatus wherein movable legs comprises a transverse sliding mechanism. A level sensor is attached to each movable leg wherein a control unit receives data from sensor, which senses deflection due to undulation in ground surface and gives command to that particular movable leg by coordination with other sensors attached with other movable legs to maintain constant level with respect to ground surface.

Another object of the present invention is to provide an apparatus wherein a main frame consists of movable leg connected at each corner or sides.

Still another object of the present invention is to provide an apparatus wherein movable legs comprises transverse sliding mechanism to adjust level of apparatus.

Yet another object of the present invention is to provide an apparatus wherein transverse movement of movable legs is controlled by means of an electric motor.

Another object of the present invention is to provide an apparatus wherein one end of the movable legs is connected to ground engaging member.

Still another object of the present invention is to provide an apparatus wherein movable legs moves in with coordination other legs connected to the said apparatus.

Another object of the present invention is to provide an apparatus wherein level sensor sense rate of deflection of height datum member and triggers said legs to move accordingly by considering other sensors connected with other movable legs.

Yet another object of the present invention is to provide an apparatus wherein transverse movement of the movable legs is controlled manually.

Another object of the present invention is to provide an apparatus wherein there is no need of skilled person to operate said apparatus.

Another object of the present invention is to provide an apparatus, which achieves uniform finish and level of road or canal layer.

Still another object of the present invention is to provide an apparatus, which has negligible maintenance as compared to hydraulic system and hydraulic jacks.

Another object of the present invention is to provide an apparatus, which is operated by means of electrical system therefore running cost is low.

The present invention relates to a pitch control apparatus for paving machine. The apparatus consists of a mainframe and movable legs. The mainframe is mounted on movable legs. Level sensors are attached to the movable legs. The control unit receives data from the level sensors, which senses the deflection due to uneven ground level. The control unit sends signal to other level sensors of other movable legs to maintain constant level with respect to the surface of ground.

BRIEF DESCRIPTION OF DRAWINGS:

Figure 1:- Illustrates the perspective view of pitching control apparatus for paving machine
Figure 2:- Illustrates an embodiment wherein the movable leg is connected with at least one sensor
Figure 3:- Illustrates cross-sectional view of movable leg
Figure 4:- Illustrates exploded view of movable leg
Figure 5:- Illustrates an electric motor
Figure 6:- Illustrates coupling joint
Figure 7:- Illustrates outer hollow shaft of movable leg
Figure 8:- Illustrates inner hollow shaft of movable leg
Figure 9:- Illustrates jackshaft and nut of movable leg

DETAILED DESCRIPTION OF THE INVENTION:

The present invention relates to a pitch control apparatus for paving machine. The pitch control apparatus comprises of a mainframe and movable legs. The mainframe is mounted on movable legs. The movable legs are connected to the ground-engaging member. The movable legs comprises of transverse sliding mechanism. The transverse sliding mechanism moves the movable legs in upward and downward direction. The level sensors are attached to the movable legs. There is a control unit provided in the level sensor. The level sensor senses the deflection due to undulation of the ground through height datum member and commands the sensors of other movable legs to adjust the height accordingly.

As shown in Figure 1 of the present invention, it relates to the perspective view of the pitch control apparatus 100 for paving machine. The pitching control apparatus 100 comprises of mainframe 200, moving legs 500, ground engaging member 30, transverse sliding mechanism 300, level sensor 10, sensor element 10’, electric motor 20, height datum member 40, gearbox 21, coupling 22, key slot 22’, jackshaft 23, upper rod 23’, nut 24, outer hollow shaft 25, inner hollow shaft 26, support member 27, controller 50. The movable legs 500 are attached to the ends of the mainframe 200. The movable legs 500 are in contact with ground through ground engaging member 30. The movable legs 500 moves in upward and downward direction through transverse sliding mechanism 300. The level sensors 10 are attached to each of the movable legs 500. The level sensors 10 comprises of sensor elements 10’. The level sensors 10 senses the deflections on the ground through height datum member 40. The level sensor 10 receives the signals through controller 50. The level sensor 10 senses the deflection and commands other level sensors 10 of the other movable leg 500, which adjusts the height of the movable legs 500 resulting in smooth working movement of the apparatus 100.

As shown in Figure 2 of the present invention, it relates to the embodiment wherein movable leg 500 is connected to at least one level sensor 10. The movable leg 500 comprises of first electric motor 20, which provides power to the jackshaft 23 coupled with said first electric motor 20 by means of coupling 22. Gearbox 21 is located between first electric motor 20 and jackshaft 23 to vary speed. Wherein, outer hollow shaft 25 comprises a support member 27, which provide support to the jackshaft 23. Inner hollow shaft 26 comprises a nut 24 mounted onto said inner shaft 26. The level sensor 10 is attached to each movable leg 500 wherein a level sensor 10 triggers to said movable legs 500 with coordination of other movable legs 500 connected with said apparatus 100 to maintain constant level of paving machine with respect to ground surface. A sensor element 10’ of a sensor 10 takes reference of level by means of attaching with height datum member 40. A control unit 50 is connected with level sensors 10 and movable legs 500 to control signal.

As shown in Figure 3 of the present invention, it relates to cross-sectional view of the movable legs 500 showing the clear arrangement of the components. The movable leg 500 comprises of an electric motor 20, gearbox 21, coupling 22, jackshaft 23, nut 24, outer hollow shaft 25 and inner hollow shaft 26. The movable legs 500 moves in transverse direction through sliding transverse mechanism 300. The movable legs 500 are connected to the linear motion mechanism 31. The second electric motor 28 is mounted on the ground-engaging member 30. The level sensor 10 are connected to the movable legs 500. The level sensor 10 senses the deflection due to undulation on the ground through height datum member 40, receives signals through controller 50 and commands other level sensors 10 of other movable legs 500 to adjust their height.

As shown in Figure 4 of the present invention, it relates to the exploded view of movable leg 500. The movable leg 500 is mounted on the sliding motion mechanism 31. The first electric motor 20 on receiving signal from the controller 50 drives the gearbox 21. The gearbox 21 drives the jackshaft 23 through coupling 22. The jackshaft 23 is housed in inner hollow shaft 26. The inner hollow shaft 26 is housed in outer hollow shaft 25. The gearbox 21 adjusts the height of the movable leg 500 by operating the gearbox 21.

As shown in Figure 5 of the present invention, it relates to the first electric motor 20 of the apparatus 100. The first electric motor 20 is connected to the gearbox 21. The first electric motor 20 receives signal from the controller 50. The first electric motor 20 drives the gearbox 21. The gearbox 21 is attached to the jackshaft 23 through coupling 22. The jackshaft 23 is housed in the inner hollow shaft 26. The inner hollow shaft 26 is housed in the outer hollow shaft 25. The electric motor 20 receives the signal from controller 50 and adjusts the height of the movable leg 500 through gearbox 21.

As shown in Figure 6 of the present invention, it relates to the coupling 22. There is a key slot 22’ is provided in the coupling 22. The first electric motor 20 gives power to the jackshaft 23 by means of coupling 22. The coupling 22 provides linear movement to jackshaft 23 through gearbox 21. The key slot 22’ of coupling 22 is provided to connect the shaft of jackshaft 23 and shaft of electric motor 20. The key slot 22’ prevents the shaft of jackshaft 23 and shaft of electric motor 20 from separating while the apparatus 100 is in working condition.

As shown in Figure 7 of the present invention, it relates to the outer hollow shaft 25. The outer hollow shaft 25 provides support to jackshaft 23 and nut 24. The outer hollow shaft 25 houses inner hollow shaft 26 inside it. The outer hollow shaft 25 is mounted on the ground-engaging member 30. The outer hollow shaft 25 is operated by the jackshaft 23 through coupling 22. The first electric motor 20 receives signal from controller 50. The first electric motor 20 operates the gearbox 21. The gearbox 21 drives the jackshaft 23 though coupling 22. The jackshaft 23 operates the outer hollow shaft 25. The outer hollow shaft 25 adjusts the height of the movable leg 500.

As shown in Figure 8 of the present invention, it relates to the inner hollow shaft 26. The inner hollow shaft 26 is mounted on the ground-engaging member 30. The inner hollow shaft 26 supports the jackshaft 23 and nut 24. The inner hollow shaft 26 is housed inside the outer hollow shaft 25.

As shown in Figure 9 of the present invention, it relates to the jackshaft 23, upper rod 23’ and nut 24. The jackshaft 23 is provided with external threads. The upper rod 23’ connects the first electric motor 20 to the jackshaft 23 through coupling 20. The nut 24 is connected to the inner hollow shaft 26 through internal threads. The support member 27 supports the jackshaft 23 and nut 24. The gearbox 21 drives the jackshaft 23 and nut 24. The jackshaft 23 and nut 24 operates the outer hollow shaft 25 and inner hollow shaft 26 resulting in adjustment of height of the movable leg 500.

The present invention relates to the pitching apparatus 100 for the paving machine. The pitching apparatus 100 comprises of mainframe 200, movable leg 500, level sensor 10, height datum member 40 and controller 50. The movable legs 500 are attached to the corners of mainframe 200. The movable leg 500 comprises of transverse sliding mechanism 300. The transverse sliding mechanism 300 moves the movable legs 500 in upward and downward direction. The movable legs 500 remains in contact with ground through ground-engaging member 30. The movable legs 500 are connected to the level sensor 10. The level sensor 10 senses the deflection due to undulation of ground through height datum member 40 and sends signal to the controller 50. The level sensor 10 of one movable leg 500 sends signal to other level sensors 10 of other movable legs 500 resulting in smooth and even working of apparatus 100. The signal from controller 50 is sent to the first electric motor 20 through sensor element 10’. The first electric motor 20 drives the gearbox 21. The gearbox operates the jackshaft 23 and nut 24 through coupling 22. The jackshaft 23 and nut operates the outer hollow shaft 25 and inner hollow shaft 26 resulting in adjusting of height of movable legs 500.

In one of the preferred embodiment, the mainframe 200 consists of movable legs 500 at each corners of the mainframe 200.

In one of the preferred embodiment, the movable legs 500 are mounted pivotally or hinged with the mainframe 200.

In one of the preferred embodiment, the axis of movable legs 500 is perpendicular to the axis of mainframe 200.

In one of the preferred embodiment, the movable legs 500 are four, six, eight or ten in number depending on the size of the mainframe 200.

In one of the preferred embodiment, movable legs 500 supports the mainframe 200.

In one of the preferred embodiment, the transverse sliding mechanism 300 provides upward and downward movement to the movable legs 500.

In one of the preferred embodiment, the transverse sliding mechanism 300 comprises any mechanism that provides linear motion from rotary motion or rotary motion from linear motion such as rack and pinion mechanism, crank slider mechanism, jack mechanism, screw and nut mechanism.

In one of the preferred embodiment, the movable legs 500 are connected to the level sensors 10.

In one of the preferred embodiment, the movable legs 500 remains in contact with ground through ground-engaging member 30.

In one of the preferred embodiment, the ground-engaging member 30 is a wheel powered by gears, chain, belt drive and sprocket linked to metallic belt.

In of the preferred embodiment, the ground-engaging member 30 are wheels, which are wear resistant.

In one of the preferred embodiment, the second electric motor 28 moves the ground-engaging member 30 in transverse direction.

In one of the preferred embodiment, the level sensor 10 senses signal of deflection from undulation of ground from height datum member 40 and sends the signal to controller 50.

In one of the preferred embodiment, the level sensor 10 is connected to the encoder (not shown).

In one of the preferred embodiment, the level sensor 10 receives the signal from height datum member 40 through sensor element 10’.

In one of the preferred embodiment, the rate of deflection in height of level senor 10 sends signal to the sensor unit 11 (not shown). The controller 50 processes signals based on height difference and sends appropriate signals to the appropriate first electric motor 20 for increment or decrement in height of movable legs 500.

In one of the preferred embodiment, the signal produced by the level sensor 10 is same as the reduced height of the movable leg and the removal of error in signal brings the movable leg 500 to equal height of other movable legs 500.

In one of the preferred embodiment, the level sensors 10 are vision & imaging sensor, proximity sensor, position sensor, vibrating sensor, ultrasonic sensor, capacitance level sensor, optical level sensor and microwave optical level sensor.

In one of the preferred embodiment, the controller 50 sends signal to second electric motor 28.

In one of the preferred embodiment, the first electric motor 20 and second electric motor 28 are AC brushless motors, DC brushed motor, DC brushless motor, direct drive, linear motors, servomotor and stepper motor.

In one of the preferred embodiment, the first electric motor 20 drives the gearbox 21. The gearbox 21 drives jackshaft 23 and nut 24.

In one of the preferred embodiment, the first electric motor 20 is connected to the jackshaft 23 through coupling 22.

In one of the preferred embodiment, the upper rod 23’ mounted on jackshaft 23 connects the first electric motor 20 to the jackshaft 23 through coupling 22.

In one of the preferred embodiment, the coupling 22 is a flange coupling, jaw coupling, sleeve coupling, tire coupling, disc coupling, diaphragm coupling, gear coupling grid coupling and roller chain coupling.

In one of the preferred embodiment, the jackshaft 23 is provided with external threads.

In one of the preferred embodiment, the key slot 22’ of coupling 22 connects shaft of first electric motor 20 and shaft of jackshaft 23.

In one of the preferred embodiment, the support member 27 supports the jackshaft 23 and nut 24.

In one of the preferred embodiment the jackshaft 23 and nut 24 operates the outer hollow shaft 25 and inner hollow shaft 26.

In one of the preferred embodiment, the axis of jackshaft 23 is in line with axis of outer hollow shaft 25 and inner hollow shaft 26.

In one of the preferred embodiment, the nut 24 is connected to the inner hollow shaft 26 through internal threads.

In one of the preferred embodiment, the internal and external threads of jackshaft 23 an nut 24 are square thread, acme thread, BSW thread, knuckle thread, buttress thread, metric thread and American standard thread.

In one of the preferred embodiment, the outer hollow shaft 25 and inner hollow shaft 26 results in adjustment of height of movable legs 500.

Other than that, the hydraulic arrangement results in adjustment of height of movable legs 500 ,CLAIMS:[CLAIM 1] An automatic pitch control apparatus 100 for paving machine comprises of:
a) a mainframe 200;
b) at least four movable legs 500 to support the mainframe 200;
c) each movable leg 500 consisting of transverse sliding mechanism 300 to provide upward & downward movement to movable legs 500;
d) at least one level sensor 10, connected to each movable leg 500;
e) level sensor 10 drives each movable leg 500 in coordination with other movable legs 500 and maintain constant level of mainframe 200 of paving machine with respect to ground surface.

[CLAIM 2] The automatic pitch control apparatus 100 for paving machine as claimed in claim 1, wherein the transverse sliding mechanism 300 comprises of;
a) first electric motor 20 receives signal from controller 50 of the deflection due to undulation of ground;
b) first electric motor 20 drives the gearbox 21;
c) gearbox 21 drives jackshaft 23 and nut 24 through coupling 22;
d) support member 27 support jackshaft 23 and nut 24;
e) jackshaft 23 and nut 24 drives the outer hollow shaft 25 and inner hollow shaft 26 in upward and downward direction to adjust the height of movable legs 500;

[CLAIM 3] A method of levelling road using an automatic pitch control apparatus 100 for paving machine comprises of;
a) mainframe 200 mounted on at least four movable legs 500;
b) movable legs 500 to support and move the mainframe 200 in transverse direction;
c) transverse sliding mechanism 300 to adjust the height of movable legs 500;
d) ground-engaging member 30 to keep movable leg 500 in contact with ground;
e) second electric motor 28 to drive the ground-engaging member 30;
f) level sensor 10 attached to the movable leg 500 to sense the deflection due to undulation of ground from height datum member 40 through sensor element 10’;
g) controller 50 to receive the signal from level sensor 10;
h) controller 50 to send the signal to first electric motor 20;
i) first electric motor 20 drives the gearbox 21;
j) gearbox 21 drives jackshaft 23 and nut 24 through coupling 22;
k) the support member 27 to support jackshaft 23 and nut 2;
l) jackshaft 23 and nut 24 drives the outer hollow shaft 25 and inner hollow shaft 26 resulting in adjustment of height of movable legs 500;

[CLAIM 4] The method of levelling road using an automatic pitch control apparatus 100 for paving machine as claimed in claim 3, wherein the movable legs 500 are mounted pivotally or hinged to the mainframe 200;

[CLAIM 5] The method of levelling road using an automatic pitch control apparatus 100 for paving machine as claimed in claim 3, wherein the movable legs 500 are four, six, eight or ten in number depending on the size of mainframe 200;

[CLAIM 6] The method of levelling road using an automatic pitch control apparatus 100 for paving machine as claimed in claim 3, wherein the transverse sliding mechanism 300 is rack and pinion mechanism, crank slider mechanism, screw & jack mechanism or screw and nut mechanism;

[CLAIM 7] The method of levelling road using an automatic pitch control apparatus 100 for paving machine as claimed in claim 3, wherein the wherein the ground-engaging member 30 is a wear resistant wheel driven by second electric motor 28, gears, chain, belt drive or sprocket linked to metallic belt;

[CLAIM 8] The method of levelling road using an automatic pitch control apparatus 100 for paving machine as claimed in claim 3, wherein the level sensor 10 is connected to the encoder and the level sensor 10 is vision & imaging sensor, proximity sensor, position sensor, vibrating sensor, ultrasonic sensor, capacitance level sensor, optical level sensor, microwave optical level sensor;

[CLAIM 9] The method of levelling road using an automatic pitch control apparatus 100 for paving machine as claimed in claim 3, wherein the first electric motor 20 is AC brushless, DC brushed, DC brushless, direct drive linear motor, servo motor or stepper motor;

[CLAIM 10] The method of levelling road using an automatic pitch control apparatus 100 for paving machine as claimed in claim 3, wherein the coupling 22 is flange coupling, jaw coupling, sleeve coupling, disc coupling, diaphragm coupling, gear coupling, grid coupling or roller chain coupling;

[CLAIM 11] The method of levelling road using an automatic pitch control apparatus 100 for paving machine as claimed in claim 3, wherein the jackshaft 23 has external threads and nut 24 has internal threads;

[CLAIM 12] The method of levelling road using an automatic pitch control apparatus 100 for paving machine as claimed in claim 11, wherein the external threads of jackshaft 23 and internal threads of nut 24 are square thread, acme thread, BSW thread, buttress thread, knuckle thread, metric thread or American standard thread