Abstract:
An infeed conveyor is provided with high pivot capability. High pivot capability is the capability to raise the elevation of at least one end of an infeed conveyor belt to an elevation higher than regular horizontal operation if the belt placer is operating lower than the surrounding grade. High pivot capability prevents the infeed conveyor from bottoming out on the grade of the haul road or adjacent pavement; and in some instances, high pivot capability allows use of the belt placer under conditions that belt placers without high pivot capability could not operate. Also disclosed is the ability for belt placers to be used to pave in both forward and reverse directions, whereas former belt placers could only pave in the forward direction. This is accomplished by the ability to rotate the discharge conveyor under one side of the belt placer, and changing the direction in which the belt placer travels. A belt placer and method of using a belt placer for conveying construction materials including a device for modifying the location of the strike-off from a position of first spreading location, around the belt placer to a position of second and diametrical strike-off location.

Description:
BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     This invention relates to track driven belt placers for conveying construction materials to a graded surface during construction. 
     2. Description of the Prior Art 
     Belt placers are commonly used as the first step in a four-step paving process. First, the road bed is cleared, prepared and graded. 
     Second, belt placers travel via track assemblies slowly and longitudinally along the paving direction, conveying construction materials, usually wet concrete, from a concrete supply truck to the graded road bed. The wet concrete is first loaded onto an infeed conveyor belt. This belt is capable of folding upward by use of an elbow joint, allowing trucks to drive past the belt prior to unloading the wet concrete or other construction material. This capability allows all of the trucks to travel in a straight line, creating safer and more efficient paving projects. 
     Next, the infeed conveyor belt conveys the wet concrete to either a second belt the discharge conveyor belt, or a spreader auger. Either the discharge conveyor belt or the spreader auger uniformly spreads the wet concrete across the graded road bed. 
     The third step of the paving process involves leveling, compacting, and forming the wet concrete through use of a slipform paver. Optionally, the fourth step cures and textures the wet concrete by use of a third machine. Typically these machines operate in close tandem, in order to avoid too much concrete setting during the road forming process. 
     After a truck pulls past the infeed conveyor belt, the truck is ready to discharge its load of concrete onto the infeed conveyor belt. Because the truck discharge is designed to quickly transfer large amounts of wet concrete to the belt placer, the transfer is not a precision operation. For example, belt placers are capable of handling approximately twenty (20) cubic yards in a minute. Invariably, the concrete splashes around the work area and eventually solidifies on the equipment. This has the undesirable consequence of hardening on some of the equipment that must maintain mobility in order to function properly. To prevent some of the concrete untidiness, fixed and manually pivoting skirting is used to protect some of the rollers underneath the belt and to facilitate lubrication of the rollers. 
     Traditionally, infeed conveyor belts are capable of folding upward to allow the concrete supply truck to drive a straight path on a haul road or adjacent pavement and pass the infeed conveyor belt prior to loading the belt placer. This capability works well to increase the speed of the paving process, but only if the supply truck is at the same elevation as the belt placer. If the supply truck is on a haul road or adjacent pavement that is not level with the surface that the belt placer is traveling, the infeed conveyor belt often bottoms out because the supply truck is usually higher than the graded surface. Alternatively, some belt placers are capable of raising or lowering one side of the machine in an attempt to level the machine with the haul road or adjacent pavement. 
     On the discharge end of the belt placer, discharge conveyor belts traditionally have the capability of rotating approximately 40°. This rotational capability allows the operator to spread the wet concrete more evenly and efficiently across the graded bed. However, this limited range of rotational capability does not work well if the belt placer has to place concrete across the entire length of an obstacle oriented perpendicular to the paving direction, such as a trench crossing. Alternatively, augers are used to spread the wet concrete in an even and efficient manner. Both of these methods prove useful for paving in one direction, and when few paving obstacles exist. 
     However, in order to change paving direction, the operator would have to turn the bulky and cumbersome machine around, once again decreasing efficiency. These mobilizations prove costly and time consuming, as well as presenting an element of risk to worker safety. 
     SUMMARY OF THE INVENTION 
     In order to solve the foregoing shortcomings of traditional belt placers, the invention herein relates to improved belt placers. 
     According to one aspect of this invention, an infeed conveyor is provided with high pivot capability. High pivot capability is the capability to raise the conveyor belt folding point, and thus the distal end of the infeed conveyor to an elevation of up to and exceeding 22″ higher than regular horizontal operation if the belt placer is operating lower than the surrounding grade. High pivot capability prevents the infeed conveyor from bottoming out on the grade of the haul road or adjacent pavement; and in some instances, high pivot capability allows use of the belt placer under conditions that belt placers without high pivot capability could not operate. 
     An infeed conveyor for conveying construction materials from a truck is disclosed, the infeed conveyor comprising: an endless conveyor belt with a folding point, and means for raising and lowering the folding point to provide high pivot capability for the infeed conveyor. 
     A method of conveying construction material from a truck situated on a haul road or adjacent pavement with a grade higher than a grade that a belt placer travels on is also disclosed, the method comprising: pivoting an infeed conveyor to raise at least a portion of the bottom of the infeed conveyor to a height above the grade of the haul road or adjacent pavement; folding an infeed conveyor from a horizontal to a vertical position; allowing a truck to drive past the infeed conveyor; unfolding the infeed conveyor from the vertical to the horizontal position; and receiving construction material from the truck onto the endless conveyor belt. If the infeed conveyor has a folding point, the method can include raising the folding point of the infeed conveyor. 
     A high pivot assembly for raising an infeed conveyor on a belt placer is also disclosed, the high pivot assembly comprising: a high pivot leg, a lifting means, and an infeed conveyor support means. Such a high pivot assembly could include a lower lifting support, an upper lifting support, an under-conveyor support aperture, a pin, a lower lifting mechanism aperture, an immobile shaft, and an upper lifting mechanism aperture; wherein the lower lifting support is coupled to the upper lifting support, the under-conveyor support aperture creating a void through the lower lifting support, the pin coupled through the under-conveyor support aperture, the lower lifting mechanism aperture creating a void through the upper lifting support and providing a space for the lifting means to attach and lift, the immobile shaft coupled with the upper lifting support and providing the upper lifting support with a conduit for vertical movement, the upper lifting mechanism aperture creating a void through the immobile shaft and providing a space for the lifting means to attach and suspend. 
     According to another aspect of this invention, belt placers can now be used to pave in both forward and reverse directions, whereas former belt placers could only pave in the forward direction. This is accomplished by the ability to rotate the discharge conveyor under one side of the belt placer, and changing the direction in which the belt placer travels. According to this aspect of the invention, this belt placer now has no universal front and no true back. Both sides of the machine can act as the front of the machine: the traditional front of the machine acting as the front of the machine when the discharge conveyor is facing forward and the belt placer is operating in the forward direction, and the traditional front of the machine acting as the back of the machine when the discharge conveyor is rotated to the back side of the machine and the belt placer is operating in the reverse direction. 
     A belt placer for conveying construction materials is disclosed, the belt placer comprising: an infeed conveyor and a discharge conveyor, and means for rotating the discharge conveyor from a position of first discharge direction, under one side of the belt placer, to a position of second and diametrical discharge direction. A belt placer thus used could have a discharge conveyor frame pivot assembly, a hub, a pivot shaft, a pin roller, a truarc ring, a yoke roller, and an greasable shaft fitting; wherein the pin roller, the truarc ring, and the yoke roller are coupled with the hub and a discharge conveyor belt carriage assembly, the pivot shaft is threadedly coupled to the hub, and preferably a greasable shaft fitting is within the pivot shaft. 
     Also disclosed is a method of changing the orientation of paving direction and discharge direction of construction materials using a three-track belt placer, the method comprising: detaching a discharge conveyor belt from a swing arm; rotating the discharge conveyor belt under one hydraulic support leg; lowering the first hydraulic support leg; raising a track assembly; rotating the discharge conveyor belt under the track assembly, lowering the track assembly, raising another hydraulic support leg, rotating the discharge conveyor belt under the second hydraulic support leg, and then attaching the discharge conveyor belt to a swing arm located on the second side of the belt placer. A modified method can be used to change paving direction and discharge direction of construction materials using a four-track belt placer, by simply raising a second track assembly, and rotating the discharge conveyor belt under the second track assembly. 
     According to another aspect of this invention, similar to the last aspect, an auger strike-off can be repositioned from one side of the belt placer to the other side, again with the effect that the belt placer has no universal paving direction. 
     A belt placer for conveying construction materials is disclosed, the belt placer comprising: an infeed conveyor and an auger strike-off, and a means for modifying the location of the strike-off from a position of first spreading location, around the belt placer to a position of second and diametrical strike-off location. 
    
    
     DESCRIPTION OF THE DRAWINGS 
     FIG. 1 is a side view of a belt placer, showing the infeed conveyor with capability to fold from A to B. 
     FIG. 2 is a top view of a belt placer, showing a discharge conveyor capable of rotating to both sides of a belt placer. 
     FIG. 3A is a side view of the prior art without high pivot capability. 
     FIG. 3B is a side view of a belt placer with high pivot capability. 
     FIGS. 4A,  4 B,  4 C, and  4 D show different side views of a high pivot kit. 
     FIG. 4E shows a roller pin. 
     FIG. 5 shows a diagrammatic top view of a main frame, a discharge conveyor belt pivot assembly, and a swing arm. This drawing shows how the discharge conveyor belt pivot assembly and swing arm interact during rotation, and is not shown as a limitation on the rotational capabilities of the discharge conveyor. 
     FIG. 6A is a side view of a discharge conveyor frame pivot assembly, swing arm, and discharge conveyor. 
     FIG. 6B is a cross-sectional view of a swing arm mounted on a main frame of a belt placer. 
     FIG. FIG. 6C is a cross section of a discharge conveyor frame pivot assembly. 
     FIG. 6D is a bottom view of a portion of a discharge conveyor belt carriage assembly. 
     FIG. 6E shows the discharge conveyor pivot assembly as viewed from the direction of construction material discharge. 
     FIGS. 7 a ,  7   b  show a top view of a belt placer with greater than 180° rotational capabilities for the auger strike-off assembly. 
     FIG. 8 shows a perspective view of one hydraulic support leg, common in the belt placer art. 
    
    
     DETAILED DESCRIPTION 
     Although the disclosure hereof is detailed and exact to enable those skilled in the art to practice the invention, the physical embodiments herein disclosed merely exemplify the invention which may be embodied in other specific structure. While the preferred embodiment has been described, the details may be changed without departing from the invention, which is defined by the claims. 
     With reference to the drawings in general, and to FIGS. 1,  2  &amp;  3 B in particular, the track belt placer is generally shown as  5 . 
     Referring to FIG. 1, the main frame  85  can be seen connected to the end frame  87 . The end frame  87  is connected to the track support structure  54 , supporting the track assembly  95 . The main frame  85  has a main frame recess  89  to receive torque hub  20  during high pivoting, and holds the engine and fuel tank  99 , as well as the infeed conveyor control panel  93 . The main frame  85  also supports the swing arm  56 , which in turn supports discharge conveyor pivot assembly  52 , which in turn supports the discharge conveyor  50 . The high pivot torque hub  20  is also supported by the main frame  85 , and the torque hub  20  supports the proximal portion  14  of the infeed conveyor  10  and supplies the endless conveyor  10  with motion. Between the proximal portion  14  of the infeed conveyor  10  and the distal portion  12  of the infeed conveyor  10  is a belt folding point  13 . A high pivot assembly  40  is provided to raise and lower the belt folding point  13 . The infeed conveyor  10  carries the endless conveyor belt  11 . 
     Still referring to FIG. 1, belt placers commonly have belt folding capabilities, in order to raise the distal portion  12  from a horizontal position A to a vertical position B, allowing trucks to drive on a haul road or adjacent pavement past the infeed conveyor  10  prior to unloading the wet concrete or other construction material. 
     Referring now to FIGS. 1 and 2, belt placers  5  can be seen to work substantially as follows. First, the infeed conveyor  10  is folded from a horizontal position A to a vertical position B, by operator operation of infeed conveyor control panel  93 ; thereby allowing a truck to drive past the infeed conveyor. Next, the infeed conveyor  10  is unfolded from the vertical position B to the horizontal position A, also by operator operation of infeed conveyor control panel  93 . Next, the truck unloads wet concrete or other construction material from the truck container outlet onto the endless conveyor belt  11 . In one embodiment, the endless conveyor belt  11  conveys the wet concrete or other construction material to a discharge conveyor  50 , which carries the wet concrete or other construction material to a construction material target area  1  (See FIG.  1 ). 
     Referring now to FIG. 2, the main frame  85  can also be seen to support the auger support arms  30 . Also supported by the main frame  85  is the discharge conveyor frame pivot assembly  61 . In an alternative embodiment, shown generally in FIG. 7, two auger support arms  30  can be seen to support the auger  32  (not shown in FIGS.  1 - 6 ). Conventional belt placers have only two auger support arms  30 , whereas this belt placer  5  has four auger support arms  30 , providing a belt placer  5  in accordance with the present invention to have the capability to remove the auger  32  and place the auger onto the other side of the belt placer  5 . The high pivot assembly  40  can be seen to be located adjacent to each side of the infeed conveyor  10 . Also seen in FIG. 2 is the capability to rotate each track assembly  95  from original position to the 90 degree rotated position  95 ′. Also shown in FIG. 2 is a discharge conveyor  50  positioned on a first side of the belt placer  5 . The pivotal ability of the discharge conveyor  50  is shown in phantom, including the ability to rotate discharge conveyor  50  to the second side of the belt placer  5 . 
     Referring to FIG. 3A, the shortcoming in the prior art is readily seen. If the grade of the haul road or adjacent pavement  2 ′ is level with the grade  2  under the belt placer  5 , infeed conveyor position A works suitably. However, referring  10  specifically to FIGS.  3 A and to FIG. 3B, if the grade of the haul road or adjacent pavement  2 ′ is elevated above the grade  2  under the belt placer  5 , position A is no longer feasible. To solve this problem, the infeed conveyor  10  must be raised to position A′ as shown on FIG.  3 B. This is accomplished by utilizing the high pivot assembly  40  of the present invention. 
     Referring now to FIGS.  2  and  4 A-E, the preferred embodiment of the high pivot assembly  40  includes a pair of high pivot legs  45  each having a lower lifting support  47 . Lower lifting support  47  could have an under-conveyor support aperture  42 , or could be pivotally attached directly to belt folding point  13  (See FIG.  1 ). If the high pivot leg  45  is not directly attached to the belt folding point  13 , lower lifting support  47  could have an under-conveyor support aperture  42 . Lower lifting support  47  is coupled with upper lifting support  48  having a lower lifting mechanism aperture  44 . Upper lifting support  48  is coupled with immobile shaft  41 , whereby immobile shaft  41  permits upper lifting support  48  to move linearly in both vertical directions. Also coupled with immobile shaft  41 , but between immobile shaft  41  and upper lifting support  48  is upper lifting cylinder  49  having upper lifting mechanism aperture  46 . Alternatively and preferably, affixed to immobile shaft  41  is a plate containing upper lifting mechanism aperture  46 , thus integrating immobile shaft  41  and the upper lifting mechanism aperture  46 . 
     Lifting mechanisms are well known in the art and could vary widely, including but not limited to for example a hydraulic lift, an electric or diesel or gas powered lift, a screw jack or a manually powered lift, or a winch cylinder and cables, although the preferred lifting mechanism is a hydraulic lift, the same type of hydraulic lift as shown in FIG. 6A as the lifting mechanism  72 . 
     In the preferred embodiment, however, two pivot legs  45  are provided, along with under-conveyor support aperture  42 . Between the two opposing pivot legs  45 , a pin  43  is provided, capable of bearing the weight of a loaded infeed conveyor. In place of a pin, bolts or other rods could be used. Also in the preferred embodiment, the hydraulic lift unit is suspended from upper lifting mechanism  46 , and the hydraulic lift unit is attached to the lower lifting mechanism aperture  44 . A plate  39  is provided for attaching the high pivot legs  45  to the end frame  87 , although the high pivot legs  45  could be attached to the end frame  87  through a variety of means including both mechanical fixtures and adhesives or welded bonds. 
     Referring now to FIGS. 1,  5 ,  6 A and  6 B, a swing arm  56  is provided for the discharge conveyor pivot assembly  52 . A discharge conveyor frame pivot assembly  61  is coupled to the main frame  85 , and rotates the discharge conveyor. The swing arm  56  rotates in conjunction with the discharge conveyor frame pivot assembly  61 , as shown diagrammatically in FIG.  5 . As the discharge conveyor frame pivot assembly  61  rotates, the swing arm  56  also rotates. Also included is discharge conveyor lift aperture  62 , used to connect the swing arm  56  to a lifting mechanism  72 . The lifting mechanism  72  is coupled with a yoke—rod end  84 , and the yoke—rod end  84  is coupled with the discharge conveyor  50 . The lifting mechanism  72  can be used to elevate the discharge end of the discharge conveyor  50 . 
     Again, lifting mechanisms are well known in the art and could vary widely, including but not limited to for example a hydraulic lift, an electric or diesel or gas powered lift, a screw jack or a manually powered lift, or a winch cylinder and cables, although the preferred lifting mechanism is a hydraulic lift. 
     As best shown in FIG. 6A, the discharge conveyor frame pivot assembly  61  has the capability to rotate the discharge conveyor  50  under the track assemblies  95  if the swing arm  56  is detached from the discharge conveyor  50 . 
     Referring now to FIGS. 6A and 6B, the swing arm  56  has a swing arm shaft  58 , containing swing arm connection aperture  60 . Within the aperture  60  can fit a number of common connecting and rotating mechanisms to the main frame  85 . Preferably, as shown, the swing arm  56  is connected to the main frame  85  by a top pivot bracket  80  and a bottom pivot bracket  81 . Bushings  78  and a thrust bearing  79  are also proved within the swing arm connection aperture  60 . A pivot shaft  63  is within the swing arm connection aperture  60 , provided with a lub fitting  82 . A capscrew  83  is provided atop the pivot shaft  63 . 
     Referring now to FIG. 6A, a tube—outer travel  73  is coupled with the discharge conveyor frame pivot assembly  61 , and the tube—outer travel  73  is coupled with the telescopic tube—inner travel  74 . Also provided is a roll pin  77 , capable of insertion into the pin—travel aperture  75  or the pin—operating aperture  76 . During either travel or rotation of the discharge conveyor  50  under the track assemblies  95 , the roll pin  77  is coupled with the pin—travel aperture  75 . During belt placer  5  operation, the roll pin  77  is coupled with the pin—operating aperture  76 . 
     Referring now to FIGS. 6A,  6 B,  6 C,  6 D, and  6 E, a conveyor pivot assembly  52  and discharge conveyor frame pivot assembly  61  are disclosed. A second pivot shaft  63 , preferably threaded at the upper end, is contained within the discharge conveyor frame pivot assembly  61 , coupled with hub  71 . The discharge conveyor frame pivot assembly  61  and hub  71  are supported by the main frame  85 . The bottom of the discharge conveyor frame pivot assembly  61  is preferably flat. The discharge conveyor belt carriage assembly  64  supplies the discharge conveyor belt  50  with motion as known in the conveyor belt art, but preferably planetary driven by torque hubs coupled to motors. A pin roller  65 , truarc ring  66  and yoke roller  67  are provided on the discharge conveyor frame pivot assembly  61  to facilitate rotational movement. 
     A loaded discharge conveyor  50  produces a very high moment arm, necessitating stress distribution. Preferably, as shown in FIG. 6D, four sets of pin rollers  65 , truarc rings  66  and yoke rollers  67  are provided to distribute the large amount of stress produced by a loaded discharge conveyor  50 . Any suitable method for supplying rotation to the hub can be used, but planetary driven torque hubs or plain motors are examples. 
     Preferably, a cover  68  is provided for the pivot shaft  63 , preferably coated with #2 PERMATEX or other resilient coating for heat and oil resistance and lubricity. Preferably, at the lower end of the pivot shaft  63  is a greasable shaft fitting  69  or other fitting for lubrication. Connected to the discharge conveyor frame pivot assembly  61  is a discharge conveyor pivot support assembly  70 . Discharge conveyor pivot support assembly  70  supports the discharge conveyor belt  50  when the lifting mechanism  72  connected to discharge conveyor lift aperture  62  is engaged to raise the discharge end of the discharge conveyor belt  50 . 
     Fitted with a discharge conveyor frame pivot assembly  61  and associated components, the discharge conveyor belt  50  can be rotated under any of the track assemblies  95 . First, the discharge conveyor belt  50  is detached from the swing arm  56 , for example by disconnecting the lifting mechanism  72  from the discharge conveyor lift aperture  62 , or by disconnecting the lifting mechanism  72  from the yoke—rod end  84 . Next, two hydraulic support legs  96  (one shown on FIG.  8 ), common in the belt placer  5  art and usually situated immediately adjacent to the track assembly  95  on the end frame  87 , are lowered by a reciprocal moving mechanism  98 , which could vary widely, including but not limited to for example a hydraulic lift, an electric or diesel or gas powered lift, a screw jack or a manually powered lift, or a winch cylinder and cables, although the preferred lifting mechanism is a hydraulic lift. 
     The hydraulic support legs  96  commonly have rotational capability, are supplied at four corners of the belt placer  5 , and can be operated independently to raise and lower either one corner or one side of the belt placer  5 . Next, a first track assembly  95  is raised and the discharge conveyor belt  50  is rotated under the first track assembly  95  by operation of the discharge conveyor frame pivot assembly  61 , powered by conventional means and controlled by the control panel  93 . Next the first track assembly  95  is lowered. Next, the first hydraulic support leg  96  is raised, and the discharge conveyor belt  50  is rotated under the first hydraulic support leg  96 , and the first hydraulic support leg  96  is lowered. If the belt placer  5  is a three-track belt placer  5 , next, the second hydraulic support leg  96  is raised, and the discharge conveyor belt  50  is rotated under the second hydraulic support leg  96 . If the belt placer  5  is a four-track belt placer  5 , next another track assembly  95  is raised and the discharge conveyor belt  50  is rotated under the track assembly  95 , and the track assembly is then lowered; and then the second hydraulic support leg  96  is raised, and the discharge conveyor belt  50  is rotated under the second hydraulic support leg  96 . Last, the discharge conveyor lift aperture  62  is attached to either a second swing arm  56  located on the second side of the belt placer  5 , or the first swing arm  56  manually attached to the second side of the belt placer  5 . Now, the belt placer  5  is prepared to operated in a direction opposite to the first direction that the machine was operating in. This capability allows the belt placer  5  to operate either right or left, as opposed to other belt placers that are limited to one-directional paving. 
     Referring now to FIGS. 7A and 7B, if the belt placer  5  is chosen to operate in conjunction with an auger-strike off  32 , also commonly called an auger spreader, four auger support arms  30  are provided to support auger structure  32 . Auger structure  32  can be supported by a variety of methods; for example quick connect fittings, standard nuts and bolts, or fasteners. Preferably, the auger structure  32  is a crownable, split auger at all widths. As can be seen from FIGS. 7A and 7B, the auger structure  32  can be easily detached from two auger support arms  30 , and then easily reattached to the other two auger support arms  30 . In this embodiment, the belt placer  5  can travel right and left, instead of just forward, as in conventional belt placers. Also seen in FIGS. 7A and 7B is the capability to rotate the track assembly  95  from original position to the 90 degree rotated position  95 ′. 
     The foregoing is considered as illustrative only of the principles of the invention. Furthermore, since numerous modifications and changes will readily occur to those skilled in the art, it is not desired to limit the invention to the exact construction and operation shown and described. While the preferred embodiment has been described, the details may be changed without departing from the invention, which is defined by the claims.