Abstract:
A mobile vibrating screen with a readily stowable and pivoting drive system comprising a motor with an attached drive sheave, a belt, a driven sheave and plurality of universal joints which are configured to maintain a connection between the motor and an eccentric weight shaft when said drive system is switched from an operational configuration to a stowed configuration. In an alternate embodiment, some small d parts, e.g. drive shaft, need to be removed and stowed elsewhere on the plant when drive is converted from operation to transport.

Description:
FIELD OF THE INVENTION 
     The present invention generally relates to vibrating screens used in mining or road building material handling and processing. 
     BACKGROUND OF THE INVENTION 
     In the past, vibrating screen machines are normally made of a box-like structure mounted on flexible springs and contain one or multiple layers of screen mesh to sort granular materials. The different sized openings in the mesh allow sizing of materials according to the size of these openings. The box structure usually contains an eccentric weighted shaft that shakes the box and its screen mesh to agitate and separate the granular materials fed into the top of the machine. The speed at which the eccentric shaft spins is dependent on the type of screen process. Usually a higher speed is desired when sorting smaller granular materials, while slower speeds are desired for sorting coarse materials. A v-belt drive is commonly used to convert the speed of the driving motor to the desired speed of the screen shaft. Since the machine shakes from action of the eccentric weighted shaft, a flexible means of transferring power to the shaft is required to transfer power from the stationary driving motor which is necessarily located outside of the box like structure. Normally, this is accomplished using v-belts from the pulley of the motor to a pulley on the screen shaft. Either the motor is mounted on a pivoting base that allows the motor shaft to move with the screen shaft to maintain tension, or a belt tensioning idler is used to maintain belt tension between the driven pulley and the drive pulley. Many of these systems have performed well in the past. However, the pivot base method and tensioning idler method are both susceptible to belt slip and belt jump, especially when the screen is surging during startup and shutdown. Both of these also perform poorly if there is an attempt to decelerate the screen with the motor or a brake on the motor. 
     Also, the drive belts and motor are normally required to be removed to allow repositioning of the motor to minimize travel dimensions of the screen machine. 
     Consequently, there exists a need for a vibrating screen which allows the connection between the motor and the eccentric weighted shaft to remain in place during operation, transporting the screen and the process of converting from operational mode to transport mode. 
     SUMMARY OF THE INVENTION 
     It is an object of the present invention to provide a mobile vibrating screen which can be efficiently repositioned into a transport position to minimize travel dimensions. 
     It is a feature of the present invention to utilize flexible joints and a telescoping shaft. 
     It is an advantage of the present invention to provide for the ability of a transport reconfiguration without need to remove motor and v-belts or otherwise disassemble the drive. 
     The present invention is an apparatus and method for screening material which is designed to satisfy the aforementioned needs, provide the previously stated objects, include the above-listed features, and achieve the already articulated advantages. For some screening operations, the present invention is carried out in a “belt-slip-less system” in a sense that the belt slip associated with relative movement between the motor and the main large driven sheave caused by vibration of the screen during operation has been greatly reduced. 
     Accordingly, the present invention is a system and method for driving the vibration of a vibrating screen plant and easily converting into a transport mode with reduced dimensions to facilitate travel on the public roadways. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The invention may be more fully understood by reading the following description of the preferred embodiments of the invention, in conjunction with the appended drawings wherein: 
         FIG. 1  is a perspective view of the vibrating screen of the present invention, shown in a transport configuration. 
         FIG. 2  is a perspective view of the vibrating screen of  FIG. 1 , shown in an operating configuration. 
         FIG. 3  is a perspective view looking upward at an underside of a pivoting vibration drive portion of the vibrating screen of  FIG. 2 . 
         FIG. 4  is a close-up view of the vibration drive system of  FIGS. 1-3  shown in an operating configuration with exterior shielding removed to reveal the operational components. 
         FIG. 5  is a close-up view of the vibration drive system of  FIGS. 1-4  shown in a transport configuration with exterior shielding removed to reveal the operational components. 
         FIG. 6  is a schematic diagram of an embodiment of the present invention. 
         FIG. 7  is a perspective view of an alternate embodiment of the present invention. 
     
    
    
     DETAILED DESCRIPTION 
     Now referring to the drawings wherein like numerals refer to like matter throughout, and more particularly to  FIG. 1 , there is shown a vibrating screen system  100  of the present invention. Vibrating screen system  100  is a mobile system which is sized and configured to be pulled by a semi-tractor. As with most prior art mobile screens, there is a main vibrating screen assembly  102  disposed atop a deck  104  which is bounded by a safety hand railing  106  and includes a heavy unbalanced shaft or wheel, which when rotated causes the system to vibrate; other methods of inducing vibration could be substituted as well. Main vibrating screen assembly  102  can be one or more screens for sorting or discriminating matter fed into the vibrating screen system  100 . The vibration drive system  110  of the present invention is generally shown in the transport configuration where it is stowed away to reduce the overall maximum dimensions of the vibrating screen system  100 . Vibration drive system  110  is pivotally mounted on vibration drive system stationary pivot pin support  112 . Also shown is first side housing  114 , drive belt cover plate  116 , vibration drive system mounting plate  118  and pivoting support structure  120 , in stowed configuration for transport. Vibrating screen system  100  is shown having a ladder  108 . 
     Now referring to  FIG. 2 , there is shown the vibrating screen system  100  of  FIG. 1  except that the vibration drive system  110  is now downwardly deployed into an operating configuration. The drive assembly hinged cover  122  is now exposed, and the pivoting support structure  120  has been pivoted down to provide support for the now protruding vibration drive system  110 . 
     Now referring to  FIG. 3 , there is shown an upward looking view at an underside of the vibration drive system  110  of  FIG. 2  where the pivoting support structure  120  is deployed. Also shown is vibration drive system mounting plate  118 . The pivoting support structure  120  pivots about pivoting support structure pivot point  128 , and the entire vibration drive system  110  pivots about stationary support inside pin  124 . Also shown is stationary support distal pin  126 . 
     Now referring to  FIG. 4 , there is shown a perspective view of the inner workings of vibration drive system  110  after first side housing  114 , drive belt cover plate  116  drive assembly hinged cover  122  and other covers have been removed. 
     Vibration drive system motor  130  is a motor which may be electrical or a suitable substitute which is coupled to a vibration drive system motor sheave  132  which receives therein vibration drive system drive belt  134 , which is coupled to vibration drive system main large sheave  136 , which is coupled to positionally fixed drive shaft  138 , which is fixed at a location on vibration drive system mounting plate  118  by positionally fixed drive shaft mounting bracket or mounted bearing  142  and positionally fixed drive shaft mounting bracket or mounted bearing  140 . With the vibration drive system motor  130  and the vibration drive system main large sheave  136  being mounted in a fixed relative position relationship, the belt slip of some prior art systems is reduced. Positionally fixed drive shaft mounting bracket  140  and positionally fixed drive shaft mounting bracket  142  help to fix drive shaft  138  laterally and longitudinally while still allowing rotational forces to impact first universal joint  144  and telescopic drive shaft  146  and second universal joint  148 . Telescopic drive shaft  146  is configured to provide for a variable separation between brake disk  152  and wheel coupler  150  both during the process of converting from operation to transport configuration and during the vibrations occurring during operation. The brake disk  152  could be a mechanical brake, an engine brake or power reversal or other means, or it could be omitted. The drive system could be made to remain connected as described or in an alternate embodiment (see  FIG. 7 ), it could be partially disassembled. 
     Now referring to  FIG. 5 , there is shown the vibration drive system  110  of  FIG. 4  stowed in the transport configuration, which is accomplished without removing any parts. This is enabled by first universal joint  144 , and telescopic drive shaft  146  and second universal joint  148 , together which cooperate to permit easy stowing and thereby easily reducing the width of the system and facilitates transport on width limited public roadways. These items  144 ,  146 , and  148  ( FIG. 4 ) allow for a stowable drive system without the belt slippage that is common in prior art systems where a belt spans from the movable pivoting motor and drive structure to the frame of the entire system. Not having this belt and requisite idler provides for many of the benefits of the present invention. 
     Now referring to  FIG. 6 , there is shown an embodiment of the present invention generally showing a vibration drive system  111  which is similar to vibration drive system  110  in many respects. Also shown is telescopic support crank jack  200  and swing-down motor supports  202 . A disc brake disc  208  is shown coupled between positionally fixed drive shaft mounting bracket  142  and telescopic drive shaft  146 . This disc brake disc  208  is configured to mate with disc brake caliper  206  and provide for a faster shutdown procedure if desired. Also shown is screen wheel case  204  which houses the eccentric weighted shaft that shakes the screen as is well known in prior art mobile vibrating screens. 
     Now referring to  FIG. 7 , there is shown an alternate embodiment of the present invention where the following components of the drive assembly are detached and removed for transportation: wheel coupler  150 , second universal joint  148 , telescopic drive shaft  146 , and first universal joint  144 . This system can fold up and down on stationary support distal pin  124 , just as elsewhere described. First universal joint  144 , telescopic drive shaft  146  and second universal joint  148  could be used just as shown; however, these “flexible” components could be replaced with non or less-flexible components as it would no longer be needed to accommodate the requirement for folding, which is eliminated by the removal of such non-flexible items. 
     The present invention is described with belts and sheaves, but it should be understood that the power transmission could be accomplished with chains and sprockets, gears or other suitable substitutes. The term “positionally fixed” is used herein to refer to something that has a location or position that is fixed, but still permits rotational motion. The term “universal joint” is used herein to refer to a special coupler which provides for multiple degrees of freedom while maintaining a rotational connection. 
     The present invention is described as an apparatus, but it should be understood that it could be a method as well, such as: 
     a method of deploying a mobile vibrating screen material discriminator comprising the steps of: 
     providing a frame; 
     providing a screen, coupled to said frame, said screen having a predetermined opening size characteristic for discriminating a predetermined size of material from other larger material; 
     transferring energy of rotation into vibration of the screen; 
     providing a motor for generating rotational energy; 
     deploying a drive system from an operational configuration to a transport configuration, such that when said drive system is converted from said operational configuration where rotation energy is transferred from the motor to a means for transferring energy of rotation into vibration of the screen; to the transport configuration, there is no disconnection of said drive system from one of said motor and said means for transferring, there is no belt removal, and there is no moving closer together of sheaves coupled together by a first drive belt. 
     It is thought that the method and apparatus of the present invention will be understood from the foregoing description and that it will be apparent that various changes may be made in the form, construct steps, and arrangement of the parts and steps thereof, without departing from the spirit and scope of the invention or sacrificing all of their material advantages. This includes using an external thread on the lower assembly  100  and an internal thread on the upper assembly. The form herein described is merely a preferred exemplary embodiment thereof.