Claims:We Claim
1. We Claim that the eccentric Shaft is designed with the above mentioned dimensions of 90mm and 160mm and a step of 10mm and an eccentricity of 5mm.
2. We Claim that Harmonic response of the Eccentric shaft for the excitation in the range of 0-5000Hz has been studied and analysed the best range
3. We Claim that Variation of stress and displacement amplitude (frequency response) with respect to frequency has been graphically plotted and identified the best variation for the shaft design
4. We Claim that Phase response of the Eccentric shaft has also been studied. These characteristics help in better understanding of vibration response of a component subjected to dynamic loading.
5. We claim that best material suited for development of eccentric shaft for vibrating screen is structural steel.
6. A method of forming an eccentric shaft having, at each end, a first cylindrical bearing surface, for support by a frame, separated axially by an elliptical surface from a second cylindrical bearing surface axially offset from said first bearing surface for supporting a surface to be vibrated and imparting vibratory movement to said surface, from an elongate workpiece comprising: mounting said workpiece for rotation about first one longitudinal axis and then another longitudinal axis; cutting material from end portions of said workpiece about one axis to form said first cylindrical bearing surface in each end of said workpiece, and cutting another adjacent portion of said workpiece at each end about said axis; cutting material from still another adjacent portion of said workpiece at each end about a different axis to form said second cylindrical bearing surface at each end, and cutting material from said cut another section at each end about said different axis to elliptically configure said another section at each end of the workpiece.
, Description:Summary of the work
A vibrating screen machine, most commonly known as vibrating screen is a machine used in mining and mineral processing, agriculture, pharmaceutical, food, plastics and recycling.
It is a vibrating chassis that has decks of screens to classify the granulated ore material and separating it into different grades by particles size, starting from a bulk product in a continuous process, i.e., the machine is used to separate feed containing solid and crushed ores down to approx. 200 micrometers in size. These are also applicable for both perfectly wetted and dried feed.
The raw material enters from the part where the screen is fed to the opposite end in which the particles come out separately according to their size, shape or density. There are also vibrating screens that are loaded by the center and the product moves radially to the outputs that are on the periphery.
Hence the advance movement of the product is due to a combination between gravity and vibration, the screens are generally inclined at an angle.
SUMMARY OF THE INVENTION MANUFACTURING
The principal objective of the invention is to provide an eccentric shaft for vibratory machinery of the kind referred to and which overcomes the disadvantages of eccentric shafts heretofore used for similar purposes. This objective is attained by the production and use of an eccentric shaft having a cylindrical, mounting bearing section at each end, a cylindrical center section having a longitudinal axis coincident with that of the bearing sections, eccentric coupling sections outboard of the center section having coincident longitudinal axes offset from and parallel to the longitudinal axis of the center section, and an elliptical section joined to each of the coupling sections inboard of the associated mounting bearing section. Each elliptical section has a major axis the length of which is no greater than the diameter of the largest cylindrical section, and a minor axis having a length less than that of the major axis. Each elliptical section has a first semi-cylindrical surface formed on an arc having a center on the longitudinal axis of the center section and a second semi-cylindrical surface formed on an arc having its center on the longitudinal axis of the eccentric bearing sections. Each elliptical section is symmetrical about a longitudinal axis located midway between the longitudinal axis of the center section and the longitudinal axes of the eccentric coupling sections. The construction is such that no bushing inserts are required in the assembly and disassembly of the eccentric shaft with and from the remainder of the vibratory machinery.

Working Principle
A screening machine consist of a drive that induces vibration, a screen media that causes particle separation, and a deck which holds the screen media and the drive and is the mode of transport for the vibration.
By vibrating the screen, the rock will be bounced around on top of it. This means, that by the time that the rock has travelled the length of the screen, it will have had the opportunity of hitting the screen mesh at just the right angle to be able to penetrate through it. If the rock is small enough it will be removed from the circuit. The large rock will, of course, be taken to the next stage in the process.
The simplest Vibrating Screen Working Principle can be explained using the single deck screen.
The frame is mounted on springs. The vibration is generated from an unbalanced flywheel. A very erratic motion is developed when this wheel is rotated.
As the performance of this type of screen isn’t good enough to meet the requirements of most mining operations two variations of this screen has been developed namely horizontal screen and inclined vibrating screen.
The names of these screens do not reflect the angle that the screens are on, they reflect the direction of the motion that is creating the vibration.