Gate 4 - Product Explanation and Reassembly - Group 6 2012
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*The plunger is connected to a switch on the back plate which allows the user to rotate the plunger. It is an obstruction inside of the valve sleeve, and as it is rotated it becomes less obstructive to the air flow, allowing more air to pass through the valve. It can also be turned such that the motor would spin in reverse. | *The plunger is connected to a switch on the back plate which allows the user to rotate the plunger. It is an obstruction inside of the valve sleeve, and as it is rotated it becomes less obstructive to the air flow, allowing more air to pass through the valve. It can also be turned such that the motor would spin in reverse. | ||
*The switch on the back plate uses a spring inside a pin to create compression so that once the pin enters one of the grooves designated for specific pressures, it locks into place until the user applies force to move it to another setting. | *The switch on the back plate uses a spring inside a pin to create compression so that once the pin enters one of the grooves designated for specific pressures, it locks into place until the user applies force to move it to another setting. | ||
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| + | {| class="wikitable" | ||
| + | |- | ||
| + | ! scope="col"| Part | ||
| + | ! scope="col"| Assumptions | ||
| + | ! scope="col"| Equations | ||
| + | ! scope="col"| Explanation | ||
| + | |- | ||
| + | | | ||
| + | '''Plunger''' | ||
| + | | | ||
| + | *Air acts as an ideal gas | ||
| + | *Temperature is constant | ||
| + | *Total volume inside the valve sleeve is constant | ||
| + | *The amount of air in the valve at any given point is constant | ||
| + | |||
| + | | | ||
| + | '''Ideal Gas Law:''' | ||
| + | |||
| + | PV=nRT '''(1)''' | ||
| + | |||
| + | where P is the pressure, V is the volume, n is the moles of gas, R is the gas constant and T is the temperature | ||
| + | |||
| + | '''Pressure Defined:''' | ||
| + | |||
| + | P=F/A '''(2)''' | ||
| + | |||
| + | where F is the normal force per unit area A, or the force applied perpendicular to the surface | ||
| + | |||
| + | | | ||
| + | After the trigger is engaged and air is allowed to flow through, the plunger alters the volume of the container through which the air may flow. Given all of the assumptions, PV = constant. Therefore, an increase in volume given by the plunger would yield a decrease in pressure proportional to the increase in volume and vice versa. | ||
| + | |||
| + | |||
| + | Since the pressure is defined as the force perpendicular to the surface area on which it is acting, the direction of the pressure is redirected when the plunger is rotated to the reverse position, thus applying force to rotate the fins in the opposite direction. | ||
| + | |||
| + | |||
| + | |- | ||
| + | | | ||
| + | '''Back Plate and Switch''' | ||
| + | | | ||
| + | *The material of the spring is of uniform density and uniform spring constant | ||
| + | *There are no damping effects | ||
| + | |||
| + | | | ||
| + | '''Hooke’s Law:''' | ||
| + | |||
| + | F= -kx '''(3)''' | ||
| + | |||
| + | where F is the force applied by the spring, k is the spring constant which is characteristic of the spring and x is the displacement of the spring | ||
| + | |||
| + | | | ||
| + | The action of the spring pin locking into place in the grooves is defined by Hooke’s Law. | ||
| + | |} | ||
Revision as of 20:19, 29 November 2012
Click here to return to the main page for Group 6.
Contents |
Gate Introduction
This gate has several parts. The first part is project management. This section discusses the roles of each member and challenges faced. The next section is the reassembly, where videos of the wrench being reassembled are shown and the process is described. There is a section that describes the mechanisms used in the impact wrench and finally a section with three design revisions on the system level.
Project Management
This section is a table of what changes group members had to make to have the gate progress.
Critical Project Review
| Management Roles | Goals | Successes | Challenges and Resolution |
|---|---|---|---|
| Communication Liaison |
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| Project Manager and Intra-Group Communications Coordinator |
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| Technical Expert: Communications Technology |
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| Technical Experts: Dis-assembly Technicians |
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Product Reassembly
Mechanisms
This section overviews the mechanisms that are present in the impact wrench.
Mechanism: Plunger/Back Plate and Switch
The plunger acts as a gate valve, connecting the user interface (back plate) with the control of the air flow to the rotor mechanism.
- The plunger is connected to a switch on the back plate which allows the user to rotate the plunger. It is an obstruction inside of the valve sleeve, and as it is rotated it becomes less obstructive to the air flow, allowing more air to pass through the valve. It can also be turned such that the motor would spin in reverse.
- The switch on the back plate uses a spring inside a pin to create compression so that once the pin enters one of the grooves designated for specific pressures, it locks into place until the user applies force to move it to another setting.
| Part | Assumptions | Equations | Explanation |
|---|---|---|---|
|
Plunger |
|
Ideal Gas Law: PV=nRT (1) where P is the pressure, V is the volume, n is the moles of gas, R is the gas constant and T is the temperature Pressure Defined: P=F/A (2) where F is the normal force per unit area A, or the force applied perpendicular to the surface |
After the trigger is engaged and air is allowed to flow through, the plunger alters the volume of the container through which the air may flow. Given all of the assumptions, PV = constant. Therefore, an increase in volume given by the plunger would yield a decrease in pressure proportional to the increase in volume and vice versa.
|
|
Back Plate and Switch |
|
Hooke’s Law: F= -kx (3) where F is the force applied by the spring, k is the spring constant which is characteristic of the spring and x is the displacement of the spring |
The action of the spring pin locking into place in the grooves is defined by Hooke’s Law. |
Mechanism: Rotor and Fins
The rotor and fins act together as an impulse turbine to alter the pneumatic, stored energy to rotational energy via impulse, which it uses to spin the hammer.
- The fins serve as a point of impact for the compressed air flowing into the housing. The direction of the flowing air is changed, thus creating an impulse, or change in momentum that is transferred to the fins, causing the rotor to spin.
- The rotor is connected to the hammer and spins due to the force exerted by the compressed air on the fins. The spinning completes the conversion of the potential energy of the compressed air into mechanical energy and finally the torque output.
Mechanism: Trigger
The trigger is a central part of the interface between the user and the control mechanisms of the impact wrench. It is the control mechanism that serves as a signal to allow air to flow into the device.
- The trigger is engaged by the user when the user applies pressure perpendicular to the surface of the trigger.
- The force exerted by the user on the trigger overcomes a spring mechanism in order to cause the shaft attached to the trigger to push the tipper valve to a position which allows for air to flow into the wrench. When the user releases the trigger, the spring forces the trigger back into place, thus disengaging the shaft from the tipper valve and allowing the tipper valve to close, no longer allowing air to flow into the device.