Design and Fabrication Of Gearless Transmission Report Download

INTRODUCTION

Today’s world requires speed on each and every field. Hence rapidness and quick working is the most important. Now a days for achieving rapidness, various machines and equipment’s are manufactured by man. Engineer is constantly conformed to the challenges of bringing ideas and design in to reality.
New machine and techniques are being developed continuously to manufacture various products at cheaper rates and high quality. The project “GEARLESS TRANSMISSION” being compact and portable equipment, which is skillful and is having something practice in the transmitting power at right angle without any gears being manufactured. This project gives us knowledge, experience, skill and new ideas of the manufacturing. It is a working project and having guarantee of the success. El-bow mechanism is an ingenious link mechanism of slider and kinematic chain principle. This is also called as “gearless transmission mechanism” this mechanism is very useful for transmitting motion at right angles. However in certain industrial application “gearless transmission at right angle” can also work at obtuse or accurate angle plane can be compared to worm and worm gear or bevel and pinion gear which are invariably used in the industry for numerous application. The main feature for mechanism comparatively high efficiency between the input and the output power shafts with regards to the gear efficiencies.

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WORKING

The Gearless transmission or El-bow mechanism is a device for transmitting motions at any fixed angle between the driving and driven shaft. The synthesis of this mechanism would reveal that it comprises of a number of pins would be between 3 to 8 the more the pins the smoother the operation. These pins slide inside hollow cylinders thus formatting a sliding pair. Our mechanism has 3 such sliding pairs.
These cylinders are placed in a hollow pipe and are fastened at 120* to each other. This whole assembly is mounted on brackets wooden table. Power is supplied by an electric motor.
The working of the mechanism is understood by the diagram. An unused form of transmission of power on shaft located at an angle. Motion is transmitted from driving to the driven shaft through the rods which are bent to conform to the angles between the shafts. These rods are located at the holes equally spaced around a circle and they are free to slide in & out as the shaft revolves. This type of drive is especially suitable where quite operation at high speed is essential but only recommended for high duty. The operation of this transmission will be apparent by the action of one rod during a revolution. If we assume that driving shaft “A” is revolving as indicated by arrow the driven shaft B will rotate counter clockwise. As shaft A turns through half revolution C shown in the inner and most effective driving position slides out of both shafts A & B. The first half revolution and rod “C” then will be at the top then during the remaining half this rod “C” slide in wards until it again reaches to inner most position shown in Fig. in the meanwhile the other rods have of course passed through the same cycle of movements all rods are successively sliding inwards and outwards.
Although this transmission is an old one many mechanics are skeptical about its operation, however it is not only practicable but has proved satisfactory for various applications when the drive is for shafts which are permanently located at given angle. Although this illustration shows a right angle transmission this drive can be applied also to shafts located at intermediate angle between 0* and 90*.In making this transmission, it is essential to have the holes for a given rod located accurately in the same holes must be equally spaced in radial and circumferential directions, each rod should be bent to at angle at which the shaft are to be located. If the holes drilled in the ends of the shafts have “blind” or closed ends, there ought to be a small vent at the bottom of each rod hole for the escape of air compressed by the pumping action of the rods. These holes are useful for oiling to avoid blind holes shafts may have enlarged port or shoulder. This transmission may be provided centrally and in line with the axis of each shaft and provided with a circular groove at each rod or a cross-pin to permit rotation of the shaft about the rod simply active as a retaining device for shipping and handling purposed.

APPLICATION

The featured product has its widest application as an extension for a socket wrench. Here the design makes it easy to reach fasteners in the automotive and other mechanical industries, where direct access to bolts and screws is often limited. However, the possible applications for this technology extend into numerous fields. Just think of the possibilities for power transmission in push bikes, toys and hand cranked equipment, or for movement transmission in store and outdoor signage.

1. Driving for all kinds four faced tower clocks. The elbow mechanism was first used in the year 1685 for the famous London tower clock named big ben.
2. The mechanism is invariable used for multiple spindle drilling operation called the gang drilling.
3. Used for angular drilling between 0 to 90 degree position.
4. Lubrication pump for C.N.C. lathe machines.
5. The mechanism is very useful for a reaching a drive at a clumsy location.
6. Air blower for electronic and computer machine’s.
7. The elbow mechanism is used for movement of periscope in submarines.

ADVANTAGES AND DISADVANTAGES OF GEARLESS TRANSMISSION

ADVANTAGES

1. Complete freedom of Interchangeability.
2. More efficient than gear.
3. Power could be transferred to any desired angle.
4. Ease of manufacturing.
5. Misalignment of shafts can be tolerated to some extent.
6. Simpler cooling system
7. Low cost of manufacturing.
8. Portability of parts.

DISADVANTAGES

1. Does not work at very low starting torque.
2. Improper hole drilling could pose much problem.
3. Sudden load would cause mechanism breakdown.
4. Links are to be replaced after certain cycle time.
5. Speed ratio is always constant 1:1.

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Design and Fabrication Of Gearless Transmission Report Download