2.1 Definition of chain drive mechanism
The basic rule of chain drive mechanism is to transmit power one shaft to another shaft at certain center distance with the help of sprockets and chain links.
Chain drives maintain a positive speed ratio between driver and driven sprockets. The driver and driven sprockets will rotate in the same direction on typical chain drives.
2.2 Definition of lever drive
Mechanism
The basic rule of the lever is a rigid bar resting on a pivot, used to move a heavy or firmly fixed load with one end when pressure is applied to the other.
There are three classes of lever mechanism which are as below:
In this case we are using second class of lever mechanism in our wheelchair.
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It is often used to convey power to the wheels of a vehicle, particularly bicycle and motorcycle. It is also used in a wide variety of machines besides vehicles.
Advantages:-
1.As no slip takes place during chain drive, hence perfect velocity ratio is obtained.
2.Since the chains are made of metal, therefore they occupy less space in width than a belt or rope drive.
3.It may be used for both long as well as short distances.
4.It gives a high transmission efficiency (upto 98 percent).
5.It gives less load on the shafts.
6.It has the ability to transmit motion to several shafts by one chain only.
7.It transmits more power than belts.
8.It permits high speed ratio of 8 to 10 in one step.
9.It can be operated under adverse temperature and atmospheric conditions.
Disadvantages:-
1.The production cost of chains is relatively high.
2.The chain drive needs accurate mounting and careful maintenance, particularly lubrication and slack adjustment.
3.The chain drive has velocity fluctuations especially when unduly
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So better power output
2.11 Requirements of lever
To get high output force at low effort
To get user friendly condition in wheelchair
2.12 Types of chain drive
The six styles of chain used for mechanical transmission are:
Roller chain
Detachable chain
Pintle chain
Silent chain
Leaf chain
Laminated metal chain
2.13 Types of lever
Class 1: Fulcrum in the middle: the effort is applied on one side of the fulcrum and the resistance (or load) on the other side, for example, a seesaw, a crowbar or a pair of scissors. Mechanical advantage may be greater than, less than, or equal to 1.
Class 2: Resistance (or load) in the middle: the effort is applied on one side of the resistance and the fulcrum is located on the other side, for example, a wheelbarrow, a nutcracker, a bottle opener or the brake pedal of a car. Load arm is smaller than the effort arm. Mechanical advantage is always greater than 1. It is also called force multiplier
no weaker; they are simply in a starting position that results in lower tension production.
In order to test the passive sufficiency of a bi-articular structure, such as a muscle, both joints which that structure crosses must first be identified. Additionally, the movements of those two joints which will constrain that structure must be identified. Next, one joint must be selected, and placed into the position that may constrain the structure. At the same time, the other joint must be placed in the position which will NOT put further strain on that structure. The selected joint must then be measured for its range of motion. Next, the same must be done with the selected joint, but in contrast, the other joint must be placed in the position which WILL further constrain the bi-articular structure. Once that has been done, the selected joint’s range of motion must be measured once more.
Introduction During this lab you will become more familiar with the concepts of torque. The purpose of this lab is to determine if the rotational equilibrium condition, Στ = 0, holds experimentally. Equipment Meter stick (1) - no metal ends Fulcrum (1) Clamps (4) Weight Hanger (1) Mass Set (1) Digital Scale (1)
#1. We added an extended lever arm to increase the distance of the car. We put the lever arm on, because the bigger the arm, the less force required. The larger the lever arm , the less force is required to pull the string. On our car we originally had no lever arm, when we put the arm on, the cars distance changed due to the less force required to pull the string and that means
Chain and belt garage door openers work in a similar way, the difference between them being the way the drive system works.
Load acts over outer circumference of on end of the cylinder, while the other end remains against a
By going through the force diagram2 of the system below, the number of components those are highly stressed and because of which may fail or lack in desired performance is four.
The initial examples of use of force continuum were developed in the 1980s and early
This arrangement means that muscles are able to work together, allowing for one limb to be straightened by one muscle and to be bent by the other. Muscles that bend a limb are called flexors and muscles that straighten a limb are called extensors.
the arm on the catapult. My independant variables are the items and their different weights
Hypothesis: If one increases the length of a cantilever, one would expect there to be an increase in deflection/flexion of the cantilever. Similarly, if one increases the mass of the load, one would expect there to be an increase in the deflexion/flexion of the cantilever. In addition, I predict that proportionality will also occur
If the load is applied at the mid- length a=b=L/2 then mid span deflection is:
handset can give force to a spring loaded operating arm, which is connected to a
As a result of trail and error method we find the angle for the third pulley and the mass that should had be suspended from it. This will balance the forces deployed on the strings due to the other two masses. While the third force is defined as the equilibrant (������⃗������) Since it is the force that establishes the equilibrium. It is also the negative of the resultant -������⃗������ = ������⃗������ = ������⃗ ������ + ������⃗������. We gathered and recorded the mass and the angle required for the third pulley to enable to put the system into the equilibrium in table 1.
A person gains mechanical advantage from using the machine if the effort he has to exert is less than resistance.