Babyproof door knob lock
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Contents |
Executive Summary
Customer Needs
(include what you know that can help the client)
Product Use
System Function
(include pictures)
Bill of Materials (Doorknob)
| # | Name | Origin | Weight | Material | Manufacturing Process | Function |
|---|---|---|---|---|---|---|
| 1 | circular wedge | latch | -- | Aluminum | stamped | access a wedge to keep latch assembled in place inside door |
| 2 | pop rivot | latch | -- | brass | molded | holds latch case |
| 3 | turning shaft | outer doorknob | -- | steel | molded | functions key lock |
| 4 | screws x2 | outer doorknob | -- | brass plated | cold heading, thread wooling | locks inner and outer doorknobs in place |
| 5 | latch plate | latch | -- | brass | stamped | attaches to door jam (on door side) |
| 6 | strike plate | latch | -- | brass | stamped and bent | attaches to door jam, allows latch to fit in hole |
| 7 | spring | inner doorknob | -- | harden steel, nickel based alloy | wound, prehardened or hardened during fabrication | guides the lock by creating resistance in a locking shaft and keeping it aligned in a locking or unlocking position |
| 8 | lock shaft | inner doorknob | -- | plastic and brass | two molded parts, press fitted | turns shaft into lock/unlock positions |
| 9 | ring | inner doorknob | -- | aluminum | stamped | serves as a buffer between knob spring and spring housing |
| 10 | inner doorknob torsional spring | inner doorknob | -- | steel | molded and wrapped | creates resistance when turning doorknob, prevents free spinning |
| 11 | spring housing | inner doorknob | -- | brass | stamped and bent | houses and secures torsional spring |
| 12 | outer plate locking mechanism | latch | -- | brass | stamped | attaches to door, similar to strike plate |
| 13 | inner plate locking mechanism | latch | -- | brass | stamped | wedges between #12 and the door |
| 14 | latch | latch | -- | steel | molded | latches door to door jam |
| 15 | lock attachment | latch | -- | steel | molded | attaches to latch, does not slide when locked |
| 16 | face for outer doorknob | outer doorknob | -- | brass | stamped | aesthetically pleasing |
| 17 | hook | latch | -- | brass | stamped | hooks to latch or lock attachment |
| 18 | large hooks x2 | latch | -- | steel | stamped | pulls back latch |
| 19 | hook mechanism plate | latch | -- | plastic | molded/injection molding | hooks #18 to latch |
| 20 | small hook from lock | latch | -- | brass | molded | (unknown use) |
| 21 | pin | latch | -- | brass | stamped and bent | adjusts locking mechanism between two different lengths |
| 22 | black plastic | inner doorknob | -- | plastic | molded | (unknown use) |
| 23 | locking mechanism housing | latch | -- | brass | molded and hole punched | houses small pieces in latch |
| 24 | short pin | latch | -- | brass | molded | slides back and forth when size is adjusted |
| 25 | plastic hooks | latch | -- | plastic | molded | slides back and forth when size is adjusted, may pull back when hook is tilted to latch |
| 26 | latch housing | latch | -- | brass | molded and hole punched | houses mechanism controlling hooks for latch |
| 27 | sliding plate | latch | -- | brass | molded and hole punched | slides back and forth, may align holes to those in the door or second housing piece |
| 28 | two lock springs | latch | -- | steel/nickel alloy | wound | impacts latch mechanism |
| 29 | inner doorknob ring | inner doorknob | -- | aluminum | stamped and molded | locks doorknob into rose, locks doorknob's cylindrical connector |
| 30 | inner doorknob rose plate | inner doorknob | -- | brass | stamped and bent | attaches doorknob to door, acts as faceplate |
| 31 | inner doorknob rose | inner doorknob | -- | brass | stamped and bent | connects door to doorknob, attaches and connects inner and outer doorknobs |
| 32 | inner doorknob | inner doorknob | -- | brass | molded/pressed/clamped | it is gripped by the user to engage latch from inside the door |
| 33 | spring housing | outer doorknob | -- | brass | stamped and bent | houses spring mechanism on the outer doorknob |
| 34 | bottom spring plate | outer doorknob | -- | steel | stamped | spring pushes against it to create torque |
| 35 | top spring plate | outer doorknob | -- | steel | stamped | spring pushes against it to create torque |
| 36 | outer knob torsional spring | outer doorknob | -- | steel | molded/wrapped | creates resistance when turning doorknob to prevent free spinning of the knob |
| 37 | outer doorknob rose plate | outer doorknob | -- | brass | stamped and bent | attaches doorknob to door, acts as a faceplate |
| 38 | outer doorknob rose | outer doorknob | -- | steel | molded and tapped | houses screws and connects inner doorknob to outer doorknob |
| 39 | outer doorknob ring | outer doorknob | -- | aluminum | stamped and molded | secures doorknob connector into rose |
| 40 | cylindrical connector | inner doorknob | -- | steel | molded | connects doorknob to rose and secured with ring |
| 41 | spindle | outer doorknob | -- | brass plated steel | molded | semi-cylinder that wraps around the turning shaft |
| 42 | outer doorknob | outer doorknob | -- | brass | molded/pressed/clamped | is gripped by user to engage latch from outside the door |
| 43 | cone-shaped connector | outer doorknob | -- | steel | molded | secures outer doorknob to rose and houses locking mechanism, spindle, and locking shaft |
| 44 | lock mechanism | outer doorknob | -- | steel/aluminum/other | stamped/sealed/molded/assorted | mechanism engages lock |
DFMA
FMEA (doorknob)
Who Are the Stake Holders?
- Homeowners, families
- Anyone who wishes to enter or exit a door
- Anyone who wants to secure a door
What it Does and How it is Used
Secures a door
- Allows selective entry or exit
- Steps:
1. Walk to a door
2. Lift hand
3. Grasp doorknob firmly
4. Twist the knob away from door jam
5. Push or pull the door open/close
Potential Failures
- If latch disconnects or mis-aligns, door does not open
- Loosening of the knob
- Material fatigue
- Rusting and sticking
- Loss of spring constant
How Failure Affects Consumers
- Doorknob becomes difficult or impossible to operate
- Doors may or may not be opened
- Repair or replacement
How Dangerous the Failures Would Be
- Cannot leave room during an emergency
- No longer reserving privacy
- Small parts may be swallowed by children
How Likely/Often Failure Would Occur
- 5~60 years
FMEA (doorknob protector)
i think we should combine the FMEA's (doorknob and doorknob protector) into a chart...
don't edit anything under the FMEA's yet, i'll get back to it tomorrow~
DFE
Quantitative Mechanical Analysis
EIOLCA
| Production | Transportation | Use | End of Life |
|---|---|---|---|
| cell 1,1 | cell 1,2 | blank | blank |
| cell 2,1 | cell 2,2 | blank | blank |
Bill of Materials (doorknob protector)
| # | Name | Origin | Weight | Material | Manufacturing Technique | Function |
|---|---|---|---|---|---|---|
| 45 | blank | blank | -- | blank | blank | blank |
| 46 | blank | blank | -- | blank | blank | blank |
| 47 | blank | blank | -- | blank | blank | blank |
| 48 | blank | blank | -- | blank | blank | blank |
| 49 | blank | blank | -- | blank | blank | blank |
| 50 | blank | blank | -- | blank | blank | blank |
Page added by Allison Chioma Oguh, Erica Delores Pratt, Chia-Pei Denise Hsu, Fall 2007
Back to --> http://ddl.me.cmu.edu/ddwiki/index.php/24-441_Engineering_Design_Course
