Patent Application
20150003914
The present disclosure relates generally to monitoring the temperature of a screed plate and, more particularly, to mounting a temperature sensor to a screed plate.
A paving machine, such as an asphalt paver, is generally a self-propelled machine designed to receive, convey, distribute, and partially compact paving material, such as asphalt. Typically, the paving machine receives the paving material in a hopper positioned at the front of the machine, conveys the paving material from the hopper to the rear of the machine with parallel slat conveyors, distributes the paving material along a desired width, and compacts the paving material into a mat with a screed. The width of the screed, which may be adjustable, typically defines the paving width provided by the particular paving machine. In particular, some paving machines include frame portions that are hydraulically extendible in a substantially lateral direction to increase the paving width. Mechanical extensions, or screed extensions, may also be utilized for increasing the paving width provided by the base screed.
Asphalt material is more malleable at hot temperatures. When the asphalt material cools, it hardens and becomes much more difficult to shape and spread. The screed, extenders, and extensions, collectively referred to as a screed assembly, compact the asphalt material and create a finished mat. Asphalt material is provided to the paving machine at very hot temperatures (around 300 degrees Fahrenheit). If the temperature drops off too quickly, the paving machine will not be able to create a proper mat surface. For example, asphalt material being deposited at too cold a temperature could result in cracking, an uneven mat, and/or raveling. So to create a proper mat, the screed plate, extender plates, and extension plates are heated to maintain the asphalt material at a high temperature. Generally, heating elements are provided proximate to the top of the screed plate, extender plates, and extension plates to provide the required heat.
WO 2000047822 A1 to Williams et al. teaches a screed for a paver having a temperature sensor or sensors connected proximate to the screed plate for sensing temperature. The Williams reference teaches a screed for a paver having a temperature sensor or sensors connected proximate to the screed plate for sensing temperature. However, this method of measuring temperature is not always accurate and may lead to inefficient use of energy on the paving machine.
Temperature measurements from the temperature sensors are used to control the amount of energy provided to the heating elements, and thus the temperature of the screed plate. As a result, accurate measurements of the temperature of the screed plate are required to obtain a proper finished mat.
The present disclosure is directed to one or more of the problems or issues set forth above.
In one aspect, a screed includes a frame and a plate, with the frame coupled to the plate. The plate has a top surface, a thickness, and an opening in the top surface. The opening extends into the thickness and is configured to receive at least a portion of a temperature sensor.
In another aspect, a screed assembly includes a frame, a plate having a first thickness, an extender, and extender plate having a second thickness, and a first temperature sensor. The frame is coupled to the plate and the extender, and the extender is coupled to the extender plate. Additionally, the first temperature sensor is coupled to the plate and a portion of the first temperature sensor lies within the first thickness.
In yet another aspect, a paving machine includes a tractor and a screed assembly coupled to the tractor. The screed assembly includes a frame and a plate coupled to the frame. The plate has a thickness and a mating area, and the mating area is located at least partially within the thickness. The mating area is configured to receive a temperature sensor.
An exemplary embodiment of a paving machine 100 is shown generally in
Paving machine 100 may also include a conveyor for conveying the paving material received within the hopper to a screed 110, such as a free floating screed, coupled with the paving machine 100, such as via tow arms, at a rear portion of the paving machine 100. Screed 110 may smooth and, at least partially, compact the paving material into a mat on the desired paving surface. Screed 110 may also include a frame 112 and a screed plate 114 (see
The tractor portion 102 of the paving machine 100 may also include hydraulic drives and controls, along with various other known paving machine components, for operating various systems and components of the paving machine 100. The screed 110 of the paving machine 100 may also include additional components and systems, such as, for example, leveling arms, vibrators, sensors, and controllers, as are known to those skilled in the art.
A schematic view of a screed assembly 120 is shown in
Screed 110 includes a screed plate 114 and extender plate 132, and screed extension 140 includes an extension plate 142. Screed plate 114, extender plates 132, and extension plates 142 are heated and used to finish the paving mat during the paving process. Provided in each of screed plate 114, extender plates 132, and extension plates 142 are openings 150. Openings 150 facilitate the mounting of a temperature sensor 160 (see
According to one exemplary embodiment, openings 150 are threaded to allow temperature sensor 160 to be threaded into openings 150. Having openings 150 threaded also assist replacement of temperature sensor 160, should such a need arise. As one of skill in the art will appreciate, temperature sensor 160 can be any temperature sensor known in the art that is adapted to engage opening 150.
While the embodiment shown in
While
The present disclosure finds potential application in any paving machine 100 that utilizes screed 110. During paving operations, it is important that an operator receives accurate readings of the temperature of screed plate 114. Having the thermistor bead located within the thickness of screed plate 114 (or extender plate 132 or extension plate 142) increases the accuracy of the measurements provided by temperature sensor 160. Mounting temperature sensor 160 to screed plate 114 (or extender plate 132 or extension plate 142) according to one of the embodiments of the present disclosure provides more accurate temperature readings then simply mounting a temperature sensor to the top of a screed plate as is known in the art.
Adapter 170 is made out of material, such as steel, that has no or very little thermal gradient, so that temperature sensor 160 is able to provide accurate temperature readings. A benefit to using adapter 170 instead of mounting temperature sensor 160 directly into screed plate 114 (or extender plate 132 or extension plate 142) is that adapter 170 provides a greater amount of engagement to temperature sensor 160, helping to maintain temperature sensor 160 in place.
As one of skill in the art will also appreciate, screed plate 114 (or extender plate 132 or extension plate 142) will wear during paving operations. The location of the sensor portion of temperature sensor 160 may be placed far enough above the bottom surface of screed plate 114 (or extender plate 132 or extension plate 142) so that it will not become damaged during extended paving operations.
The present disclosure provides more accurate temperature readings of screed plate 114 (or extender plate 132 or extension plate 142) than those known in the art. As a result, the present disclosure allows paving machine 100 to more efficiently regulate the use of electrical power to the heating elements and create a more even and better mat.
It should be understood that the above description is intended for illustrative purposes only, and is not intended to limit the scope of the present disclosure in any way. Thus, those skilled in the art will appreciate that other aspects of the disclosure can be obtained from a study of the drawings, the disclosure, and the appended claims.
