Door damper
From DDL Wiki
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== Team Members == | == Team Members == | ||
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+ | Team members worked together in order to best utilize everyone's individual strength. Cooperation proved key to providing a quality product by deadline. | ||
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Leader : Essian Ohues | Leader : Essian Ohues | ||
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DFMA Lead : Michael Saitta | DFMA Lead : Michael Saitta | ||
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FMEA Lead : Stephen Poniatowicz | FMEA Lead : Stephen Poniatowicz | ||
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DFE Lead : Jillian Wollenberg | DFE Lead : Jillian Wollenberg | ||
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Presentation Leader : Bushra Salama | Presentation Leader : Bushra Salama | ||
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== References == | == References == |
Revision as of 15:29, 17 September 2012
Contents |
Executive Summary
A door damper is a standard piece of industrial hardware that is used on thousands of doors across America. Our team is analyzing competitor door dampers to determine the function, strengths, and weaknesses.
The competitor's damper was dissected in order to gain a better understanding of it functionality and the parts that are used. Following dissection, DFM, FMEA, and DFE analysis was performed. DFM analysis revealed that while the parts are mass produced, they are neither standardized nor easy to assemble. FMEA revealed that failures of the product are highly unlikely and unlikely to harm the user. Instead, failure modes focused around the door damper becoming unable to fulfill its purpose. DFE analysis revealed that while there was little carbon dioxide cost associated with the manufacture of the device, the hydraulic fluid used could be toxic and a hazard if disposed of improperly. The lack of proper instruction or disposal advice implies that proper disposal is unlikely if possible.
We have determined that there are several possible areas of improvement. These believe that these areas focus around on the elimination of the petroleum-based damping fluid, standardization of parts, and possible additional features.
Primary Stakeholders and Product Needs
Consumers are building owners who must absorb cost of original door damper, instillation, as well as maintenance costs and replacement. Also must consider installers (construction workers), maintenance workers, and building planers.
Stakeholder | Needs |
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Consumer |
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Retailers |
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Manufacturers |
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Shipping/Transport |
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Product Function and Evaluation
The door damper has two main roles. First, the damper closes the door automatically. Secondly, the damper ensures that the door moves at a safe and controlled rate.
Self closing functionality is achieved with the use of a spring. The spring is compressed when the door is open. It then expands and forces the door into a closed position.
Speed is controlled by moving a piston through a viscous fluid. Speed can be controlled by opening additional channels to allow the fluid less head loss.
Motion is controlled and transmitted through the use of a two bar linkage, a rack, and a pinion. This provides both mechanical advantage for the spring, as well as allowing the use of a linear spring to cause rotational motion of the door.
Steps for use
- Install door closer to door and frame
- Adjust to desired angle and closing speed
- Push/pull door open
- Allow door to close behind you
User Study
Industrial door closers are standard in their function. They can be adjusted for the angle to which the door is allowed to open, as well as the speed at which the door closes. They allow the door to open easily in a single direction and then damp the motion as the door closes in the opposite direction. The motion is usually stopped fully by the frame of the door.
Observations
- Shorter amount of time to push open a door than to pull (also easier when carrying things)
- Dampers protect walls from damage due to doors slamming
- If not damped enough the door can hit a person when closing
- Some people will fling door open as far as possible, so as not have to push door again as they walk through
- Greater effort is needed to open doors with dampers than without (adds resistance)
- Sometimes the door will be pushed open into a person on the other side
List of Parts
Design For Manufacturing and Assembly
DFM
Design for Manufacture analysis shows that the competitor’s door damper uses a number of custom parts in addition to several standard parts. As such, while an effort has been made to reduce manufacturing costs, there is a possibility that a redesign could allow a reduction in manufacturing costs.
The custom parts include the arms of the linkage, as well as the shell, rack, and pinion. Several of these parts require complex machining processes. The arms must be threaded; the rack and pinion both require precise teeth and heat treatment. Such complex custom parts significantly increase the cost of manufacturing. Furthermore, significant precision is needed in the manufacturing of the shell and caps in order to contain the hydraulic fluid.
The design does make several attempts at using standard parts such as O-rings, screws, washers, and nuts. Furthermore, several of the custom parts are used multiple times to reduce the number required. Furthermore, the custom parts are well specialized in order to best accomplish their function.
DFA
Design for Assembly analysis shows that the use of custom parts has paid off in simplifying the assembly of the competitor’s door damper. Assembly is straightforward, requiring only a few simple rivets and a few threaded connections. However, a different tool is required for each connection, thereby reducing assembly simplicity and driving up cost. Assembly is further complicated by the use of hydraulic fluid. The fluid must fill the inner shell completely without gaps or bubbles in order for the product to function properly. As such, entirely filling the product is likely to be a messy and time consuming process.
Failure Mode and Effect Analysis
Design for Environment
Team Members
Team members worked together in order to best utilize everyone's individual strength. Cooperation proved key to providing a quality product by deadline.
Leader : Essian Ohues
DFMA Lead : Michael Saitta
FMEA Lead : Stephen Poniatowicz
DFE Lead : Jillian Wollenberg
Presentation Leader : Bushra Salama