Source: http://www.google.com/patents/US4012160?dq=7,013,345/
Timestamp: 2017-08-18 22:26:49
Document Index: 478732109

Matched Legal Cases: ['arts 100', 'arts 104', 'arts 100', 'arts 104', 'arts 122', 'arts 104', 'arts 122', 'arts 92', 'arts 100', 'arts 122', 'arts 100', 'arts 122', 'arts 90', 'arts 102']

Patent US4012160 - Paving machine with enclosed material compartment - Google Patents
Two feed conveyors and two spreader augers are independently driven, each by its own drive motor. The control means for each feed conveyor includes a sensor at the discharge end of the feed conveyor and means responsive to changes in the level of the paving material at the sensor for proportionally increasing...http://www.google.com/patents/US4012160?utm_source=gb-gplus-sharePatent US4012160 - Paving machine with enclosed material compartment
Publication number US4012160 A
Application number US 05/678,146
Publication number 05678146, 678146, US 4012160 A, US 4012160A, US-A-4012160, US4012160 A, US4012160A
Inventors Jimmy L. Parker
Original Assignee Parker Jimmy L
Patent Citations (13), Referenced by (52), Classifications (4)
US 4012160 A
Two feed conveyors and two spreader augers are independently driven, each by its own drive motor. The control means for each feed conveyor includes a sensor at the discharge end of the feed conveyor and means responsive to changes in the level of the paving material at the sensor for proportionally increasing the drive speed of the conveyor as the level drops and proportionally decreasing the drive speed of the conveyor as the level rises. The control means for each auger includes a sensor adjacent the discharge end of the auger and means responsive to changes in the level of the paving material at the sensor for proportionally increasing the drive speed of the auger as the level drops and proportionally decreasing the drive speed of the auger as the level rises. The paving material compartment, which includes the feed conveyors and spreader augers, is enclosed. Fumes are pumped out from the enclosed feed path and into a pollution control device.
1. In a paving machine comprising a pair of endless feed conveyors arranged to deliver paving material rearwardly from a hopper to the inboard ends of a pair of transverse augers which spread the material outwardly and deposit it onto the surface being paved forwardly of a leveling screed which trails the augers, the improvement comprising:
control means for the feed conveyor drive means, including a separate sensor for each feed conveyor, each of which is mounted on the paving machine adjacent the discharge end of its feed conveyor and at the inboard end of the associated auger, for measuring changes in the level of the paving material deposited onto the surface below the sensor and producing a signal proportional to said changes, and means operatively connected to said sensor which is responsive to the signal indicating changes in the level of the paving material at the sensor, for proportionally and substantially instantaneously increasing the drive speed of the associated feed conveyor as the level drops and proportionally and substantially instantaneously decreasing the drive speed of such feed conveyor as the level rises;
control means for the auger drive means, including a separate sensor for each auger, each of which is mounted on the paving machine adjacent the outboard end of its auger for measuring changes in the level of the paving material deposited onto the surface below the sensor and producing a signal proportional to said changes, and means operatively connected to said sensor which is responsive to the signal indicating changes in the level of the paving material at the sensor, for proportionally and substantially instantaneously increasing the drive speed of the associated auger as the level drops and proportionally and substantially instantaneously decreasing the drive speed of such auger as the level rises, whereby the feed conveyors and the augers are continuously being independently and automatically driven at speeds proportional to the demand for paving material at the discharge ends thereof; and
2. A paving machine according to claim 1, wherein said cover means extends between a frame portion of the paving machine located forwardly of the augers and a leveling screed which trails the augers, and wherein said cover means will permit vertical movement of the leveling screed relative to said frame portion of the paving machine.
4. In a paving machine comprising a pair of endless feed conveyors arranged to deliver paving material rearwardly from a hopper to the inboard ends of a pair of transverse augers which spread the material outwardly and deposit it onto the surface being paved forwardly of a leveling screed which trails the augers, the improvement comprising:
control means for the auger drive means, including a separate sensor for each auger, each of which is mounted on the paving machine adjacent the outboard end of its auger for measuring changes in the level of the paving material deposited onto the surface below the sensor and producing a signal proportional to said changes, and means operatively connected to said sensor which is responsive to the signal indicating changes in the level of the paving material at the sensor, for proportionally and substantially instantaneously increasing the drive speed of the associated auger as the level drops and proportionally and substantially instantaneously decreasing the drive speed of such auger as the level rises, whereby the feed conveyors and the augers are continuously being independently and automatically driven at speed proportional to the demand for paving material at the discharge ends thereof;
This is a continuation-in-part of my prior copending application Ser. No. 452,056, filed Mar. 18, 1974, now Pat. No. 3,967,912 and entitled Paver Feed Control.
This invention relates to paving machines, and in particular to the provision of a completely automated paving machine capable of high speed paving over almost any type or condition of subgrade, including when variations in widths are encountered, and which includes an enclosed paving material compartment and pollution control equipment.
The type of paving machine to which this invention relates is generally characterized by a frame which is supported on and is moved forwardly by ground engaging wheels or tracks. The frame supports a hopper into which the paving material is dumped. The paving material is removed from the hopper and moved rearwardly by a pair of endless belt type feed conveyors, one on each side of the machine. The feed conveyors deposit the paving material into a transverse trough containing a pair of laterally extending spreader screws or augers. These augers spread the material out forwardly of a finishing screed which trails the augers. The finishing screed functions to screed and level the paving material.
Finishing machines of the type described are disclosed by the following U.S. Pat. Nos. 2,351,592, granted June 20, 1944 to Harry H. Barber; U.S. Pat. No. 2,589,256, granted Mar. 18, 1952, to Harold R. Horning; U.S. Pat. No. Re. 25,275, granted Oct. 30, 1962 to Harold C. Pollitz; U.S. Pat. No. 3,453,939, granted July 8, 1969 to Harold C. Pollitz, Vernon L. Schrimper and Louis F. Fairchild; 3,537,363, granted Nov. 3, 1970, to George E. Long and Howard G. Anson; 3,678,817, granted July 25, 1972, to Earl D. Martenson and James J. Gebhardt, Jr.; 3,700,288, granted Oct. 24, 1972, to Donald R. Davin and Gary H. Beckley.
Pollitz, U.S. Pat. No. Re. 25,275; Pollitz et al U.S. Pat. No. 3,453,939; Long U.S. Pat. No. 3,537,363 and Martenson et al U.S. Pat. No. 3,678,817 disclose control systems for the feed conveyors and the spreader augers which include material level sensing units positioned at the sides of the machine, adjacent the outer ends of the augers. In the machines disclosed by Pollitz U.S. Pat. No. Re. 25,275 and Pollitz et al U.S. Pat. No. 3,453,939, the sensors are in the nature of limit switches which sense only the presence of excess material and function to interrupt operation of the feed conveyor and the spreader screw on the side of the machine to which an excess of material has been delivered. Long U.S. Pat. No. 3,537,363 and Martenson et al U.S. Pat. No. 3,678,817 disclose automatic control systems for varying the drive speed of each feed conveyor and its spreader screw in response to changes in the depth of material sensed at the outboard end of a spreader screw.
All of the known paving machines require that the material compartment in which the feed equipment is located be open at the top so that the operator can look down into it and visually observe the presence, absence and/or relative position of the paving material. The exposed spreader augers present a serious hazard to the operator who must constantly be on guard against accidently stepping or falling down into the augers. Also, due to the open top, toxic fumes from the paving material flow freely upwardly to and around the operator. The fumes not breathed by him (in concentrated doses) flow into and pollute the atmosphere.
According to the invention, a separate material level sensor is located adjacent the discharge end of each feed conveyor. Each such sensor meansures the level of the paving material below it. Each feed conveyor also includes control means responsive to changes in the level of paving material at the sensor for proportionally increasing the drive speed of the feed conveyor as the level drops and proportionally decreasing the drive speed of such conveyor as the level rises. As in the systems disclosed by Long U.S. Pat. No. 3,537,363 and Martenson et al U.S. Pat. No. 3,678,817 a level sensor is also provided adjacent the outboard end of each spreader auger. However, according to the present invention, the signal generated by each such sensor is used for controlling only the drive speed of the associated spreader auger. Each spreader auger includes means responsive to changes in the level of the paving material at its sensor for proportionally increasing its drive speed as the level drops and proportionally decreasing its drive speed as the level rises.
The automatic paver feed control makes it possible to accomplish several things in the paving machine of the present invention that cannot be accomplished in the prior art machines. The automatic paver feed control completely removes the human element in the operation of the material feed process. The operator does not have to watch the level of mix at the ends of the auger or at any other location in the path of travel of the paving material. This feature makes it possible to protect the operator from poisonous fumes, the environment from pollution, and everyone who has a need to go onto the machine from accidental injury by the auger system.
FIG. 14 is a view similar to FIG. 2, of the same paving machine, but showing the paving material compartment being substantially enclosed, including by a cover on the hopper and a cover over the auger, and showing such machine equipped with apparatus for collecting and cleaning the vapors and/or fumes emitted from the asphalt paving material;
FIG. 15 is a fragmentary top plan view of the covered screed end portion of the paving machine, including phantom line showings of the screed extenders in their extended positions, and cover sections adapted to move in and out with the screed extenders;
FIG. 18 is a screed end elevational view of the machine, with some parts being cut away for clarity of illustration of other parts, said view including phantom line showings of the screed extenders, and the cover sections carried thereby, in their extended positions.
As shown in FIGS. 1 and 2, asphalt concrete or some other paving material PM is deposited into a hopper 10 located at the forward end of the paving machine. The floor of the hopper 10 is partially defined by the forward portions of the upper flights of a pair of endless belt type feed conveyors 12, 14. A strike-off plate 16 is provided at the downstream end of the hopper 10. The vertical height of the feed opening 18 below plate 16 helps determine the amount of material which leaves the hopper 10 on the feed conveyors 12, 14. The region between the feed opening 18 and the downstream ends of the feed conveyors 12, 14 is usually referred to as the "tunnel".
Motors M1, M2 are flow controlled motors, i.e. the drive speed varies in proportion to the flow rate of the hydraulic fluid which is delivered to them. According to an aspect of the invention, the flow to each motor M1, M2 is independently controlled by a pressure compensated, quick adjustable flow control valve. One such valve V1 is located in the delivery line 52 leading from the pump P to the motor M1 and another such valve V2 is located in the delivery line 54 leading from the pump P to the motor M2. An electric servo motor actuator A1 is associated with valve V1 and another such actuator A2 is associated with valve V2.
As a recap, flow from the pump P is metered by the pressure compensated flow control valves V1, V2 which are controlled by the electric servo motors A1, A2 to cause the hydraulic motors to turn at the desired speed. The pressure in the lines between the hydraulic motors M1, M2 and the flow control valves V1, V2 is that which is induced by the resistance to the metered flow. The pressure in the lines between the flow control valves V1, V2 and the pump P will be 150 psi above the higher of the two load induced pressures downstream of the flow control valves V1, V2. This happens as a result of the shuttle valve 68 allowing the higher of the two metered flow pressures to act on the load sensing pump controller. The pump will deliver as much as is necessary to maintain a pressure 150 psi higher than the pressure sensed at the controller port. Therefore, when the two flow control valves V1, V2 are shut off and the pressure downstream of them drops to 0 the pressure at the outlet of the pump is 150 psi and the pump delivery is 0 since there is no demand. When the pressure downstream of one flow control is 1000 psi and 2000 psi in the other, the pressure at the pump outlet will be 2150 psi and the delivery will be the sum of the two metered flows. The very least pressure drop across the flow control valves V1, V2 will be 150 psi, satisfying the required minimum of 100 psi to operate the regulating spool that is in them. The relief valve 58 is used only to limit the maximum pressure of the system to a value compatable with the components used.
The primary benefit of this design is that it is efficient. The pressure drop across the flow control valves V1, V2 is only 150 psi when the induced pressures are the same regardless of what the induced pressure is. Often systems with two or more motors running in parallel from a single variable flow source are inefficient. This is due to the need to cause the outlet pressure of the pump to be set for as high as would be required for a "worst condition". The difference between "worst condition" pressure and the induced pressure, or the pressure drop across the flow regulating valves multiplied by the flow through these valves gives an energy loss value. This can be high when light load conditions cause low induced pressures at the motors.
Referring to FIG. 5, let it be assumed that the lower grade (the grade of the ground surface being paved) quickly changes from a flat surface to a crowned surface, i.e. to a surface which slopes downwardly as it extends from the inner end to the outer end of the auger 20. The level of paving material below sensor S3 will immediately drop. When this happens the control arm of sensor S3 moves with the material and generates an electric signal which is proportional to the amount of movement. This electric signal causes a corresponding adjustment in the control valve (not shown by valves V1, V2), to increase the flow of hydraulic fluid to motor M3 so that the motor M3 will rotate faster and drive auger 20 faster. Hence, auger 20 will deliver paving material PM at a faster rate to the outboard end of the auger 20.
FIG. 9 shows a situation where the lower grade is parallel to the upper grade (i.e. the upper surface of the mat). Under this condition, the drive speed of the motor M1 can be constant and the drive speed of motor M3 can be constant. If this condition were to always exist, the feed conveyor 12 and the auger 20 could be coupled together and drive together, such as is taught by the aforementioned U.S. Pat. Nos. 3,537,363 and 3,678,817. However, this condition does not always exist, so that is why I have provided independent drive means for each feed conveyor 12, 14, independent drive means for each auger 20, 22 and automatic control means which will quickly and automatically vary the drive of each one of these feed components, as necessary, to meet the varying conditions of the surface being paved.
The independent drive means for the two feed conveyors, the independent drive means for the two auger sections, and the various sensors and control circuitry associated therewith, all of which are shown in FIGS. 1-13, have been omitted from FIGS. 14--18. This was done so that such details would not be present to distract from the details of the enclosed paving material compartment and the pollution control mechanism which is included in FIGS. 14--18. However, it is to be understood that the various mechanisms described below in connection with FIGS. 14-18 exist in a paving machine together with all of the items which are discussed above in connection with FIGS. 1-13 but which have been omitted from FIGS. 14-18.
Referring now to FIGS. 14-18, the paving machine is shown to include a cover 80 for the hopper 10, a cover 82 for the auger region 84, and pollution control apparatus, generally indicated at 86, for collecting the fumes and pollutants which are emitted by the paving material PM. The use of the covers 80, 82 and the pollution control apparatus 86 is only possible because the paving machine includes the invention that is described above in connection with FIGS. 1-13 and is claimed in my aforementioned copending application Ser. No. 452,056.
The cover 80 for hopper 10 is only diagrammatically illustrated in FIG. 14. It is shown to be pivotally mounted at 88 for pivotal movement about an axis extending transversely of the paving machine, between a "down" position wherein it extends over at least the rearward portion of the hopper 10, and an "up" position, shown by phantom lines in FIG. 14.
In the illustrated embodiment the cover 80 extends across the full width of the top of the hopper 10, but only about 1/2 of the length. Of course, it is to be understood that in other embodiments a different form of cover may be employed and it may completely cover the top of the hopper except that it is open for the purpose of adding paving material PM to the hopper 10.
In the illustrated embodiment it is contemplated that a dump truck (not shown) containing paving material PM will back up to the hopper and dump material into the hopper through the opening that is left forwardly of the cover 80. It is a common practice to elevate the box of a dump truck into a "dumping" position, with the tail gate open and the lower rear portion of the box over and/or partially within the open top of the hopper 10. Then, the dump truck and the paving machine are moved forwardly together. The opening which remains forwardly of cover 80 is sized to permit this practice. The box of the dump truck then serves to at least partially cover the top opening forwardly of cover 80.
In another installation it is contemplated that the cover 80 may be replaced by a large dimensioned fabric cover which is sized to drape over the entire top opening of hopper 10. Such a cover is either weighed at its periphery, so that the weights will hold it in place, or is provided with a suitable system of fasteners or the like. In such an embodiment the cover is rolled back a sufficient amount to permit dumping of paving material PM into the hopper 10.
The cover 82 for the auger region 84 may be constructed from a plurality of sections. A stationary section 90 may be connected to the housing H. The regions immediately over the augers 20, 22 may be covered by foldable covers 92, 94. In the illustrated embodiment the foldable covers 92, 94 are hinged along their forward edges 96, 98 to a frame portion of the vehicle. They are divided into two parts (92 into parts 100, 102 and 94 into parts 104, 106) and such parts are hinged together (parts 100, 102 by a hinge 108 and parts 104, 106 by a hinge 110).
As will hereinafter be discussed in greater detail, hose portions 114, 116 of the pollution control apparatus 86 may be detachably connected to the cover sections 92, 94 about openings provided therein. A comparison of FIGS. 14 and 16 will show that the bifurcated cover sections 92, 94 will accommodate vertical movement of the screed 24. This includes small amounts of movement for the purpose of changing the depth of the pavement and elevation of the screed 24 to a transport position (FIG. 16). Whenever it becomes necessary to gain access to the auger compartment 84, the fasteners 112 are released, the hoses 114, 116 are disconnected, and the covers 92, 94 are swung upwardly into the broken line position shown in FIG. 14.
In a machine equipped with screed extenders the cover sections 92, 94 may themselves be equipped with extensions 118, 120. As shown by FIGS. 15, 17 and 18, the extensions (extension 120 being shown by way of example in FIG. 17) may comprise two parts 122, 124 hinged together at 126, by a hinge which extends parallel to, and is immediately above, hinge 110. Guide rails 128, 130 may be provided on the cover parts 104, 106, to extend longitudinally thereof. Complementary slideways may be provided on the cover parts 122, 124 to engage the rails 128, 30 and guide movement of the extensions 118, 120 longitudinally of the cover parts 92, 94. The ends 126 may be appropriately designed so that the extensions 118, 120 will move together with the cover parts 100, 102 and 104, 106 during raising and lowering of the screed 24. As shown by FIG. 17, the extension parts 122, 124 may be slightly narrower than the cover parts 100, 102 and 104, 106, and be free of connection with anything at their front and rear edges.
As shown by FIG. 18, the screed extenders may include vertical outside side walls 132, 134. The side walls 132, 134 may be extended upwardly above the cover extensions 118, 120, so that the outer ends of the extension parts 122, 124 can abut up against the inner surface of the walls 132, 134. By this arrangement the screed 24 may be adjusted vertically in position relative to the rest of the vehicle and the cover extensions 118, 120 may move without an opening being provided endwise of cover extensions 118, 120.
As best shown by FIG. 15, the various cover parts 90, 92, 94, 118, 120 extend completely over the augers 20, 22, so that it is possible for a person to either accidentally step down into, or fall into, the auger compartment 84 and become injured by the augers 20, 22.
The illustrated embodiment shows a pollution control mechanism 18 mounted on the transverse portion 136 of the screed frame. The aforementioned hoses 114, 116 may be made from an accordian type material, so that they will accommodate relative movement of the cover parts 102, 106.
As shown by FIG. 14, an opening 40 may be provided in wall 16, at a distance above the strike-off or gauge edge 138, to provide a passageway for fumes from within the hopper 10 to the region rearwardly of wall 16. A conduit 142 may be provided for directly ducting the fumes from such opening 140 rearwardly to the auger compartment 84. Or, the opening 140 may merely communicate the hopper side of wall 16 with the opposite side thereof.
The pollution control mechansim includes a pump or fan which is arranged to draw the fumes and other pollutants from within the hopper 10, from within the paving material conveyor space rearwardly of wall 16, and from within the auger compartment 84, into a collection chamber which includes known apparatus and substances for substantially cleansing the air before it is discharged out into the atmosphere. It is believed that even though in the illustrated embodiment some opening to the atmosphere will exist forwardly of cover 80, the pump will cause at least most of the pollutants from within the hopper 10 to flow rearwardly to the pollution control apparatus 86 rather than forwardly and upwardly into the atmosphere.
The central region of the machine above the two conveyor flights 12, 14 is covered by an upper wall portion of the vehicle frame. The hopper 10 is covered either by a short cover 80, used alone, or in combination with a rear portion of a dump truck, or a larger cover as described above. The inclusion into the paving machine of the completely automatic control system for the conveyor flights 12, 14 and the auger sections 20, 22 are what makes it possible to provide a cover over the auger section 84. Such cover over the auger sections 84 prevents accidental injury by way of a person either stepping into or falling into the augers 20, 22. Such cover for the auger section, and the other above described covers, and the side and bottom portions of the material conveying compartment, provide an enclosure for the paving material PM which serves to hold in the fumes and other pollutants, and the pollution control apparatus 86 functions to collect and to a considerable extent purify the air in which such pollutants are carried.
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