Patent Application
20100314299
The present invention generally relates to vibrating screens used in mining or road building material handling and processing.
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.
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.
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:
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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
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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.
