សិល្បៈ
សម្រស់ និង សុខុមាលភាព
សិប្បកម្ម
វប្បធម៌ និង ប្រវត្តិសាស្ត្រ
ការកម្សាន្ត
បរិស្ថាន
ម្ហូប និង ភេសជ្ជៈ
វិស្វកម្មបញ្ច្រាស
វិទ្យាសាស្ត្រ
កីឡា
បច្ចេកវិទ្យា
ប្រដាប់ដែលស្លៀក
The Parking Meter: A Coin That Unlocks a Clock
By the 1930s city streets were lined with cars parked all day, and shops lost the customers who could not stop. A parking meter rations the kerb: a coin buys a set time, and a signal shows anyone passing when it has run out.
Carl C. Magee of Oklahoma City, assignor to the Dual Parking Meter Company, filed US 2,118,318, *Coin Controlled Parking Meter*, on 13 May 1935; it was granted 24 May 1938. Inside a lockable head on a post, a coin completes the winding mechanism; turning the handle winds a spring; an escapement-governed train runs it down; a signal shows while the time lasts and vanishes when it has elapsed. The last coin shows in a window, and the coins fall into a sealed container so the collections can be checked. Oklahoma City installed Magee's meters in July 1935.
This rung designs the gear train and the spring for a one-hour meter and builds a coin-interlocked timer from a wind-up motor.
មធ្យម
About 5 hours
ការណែនាំ
1
1
Gear ratio and spring energy
Gear ratio and spring energy
កំពុងផ្ទុកសៀវភៅ Jupyter…
2
2
One parking, as the patent describes it
One parking, as the patent describes it
កន្លែងធ្វើការ Blockly
Loading Blockly workspace...
3
3
What keeps the time
What keeps the time
The meter's clockwork is governed by an escapement. The embedded blueprint shows how an escapement releases a gear train one tooth at a time.
4
4
Build a coin-interlocked timer
Build a coin-interlocked timer
Take a wind-up motor mechanism and fit a pointer to its slowest output shaft; mark the run-down time of a full wind on a card dial behind it.
Make the winding key the interlock, as Magee's coin was. 3D-print a crank that drives the winding shaft through a sliding coupling: two halves with a slot between them exactly as wide as the coin. Without a coin the outer half turns freely; drop a coin into the slot and it locks the halves together, so the crank winds the spring. Put a ramp below so that when the crank has turned half a revolution the coin falls out of the slot into a box.
Try it without a coin: the crank spins, nothing winds. With a coin: one wind, the pointer runs down across its dial. Time a full run and compare with the card.
សម្ភារៈសម្រាប់ជំហាននេះ៖
យន្តការម៉ូទ័រមួល1 ដុំ
កាក់ទង់ដែង3 ដុំ
សន្លឹកឈើបន្ទះ1 ដុំ
វីសម៉ាស៊ីន6 ដុំ
ស្នៀតឈើរឹង1 ដុំឧបករណ៍ដែលត្រូវការ៖
ម៉ាស៊ីនបោះពុម្ព 3D ប្រើខ្សែ (FDM)
សរសៃ PETG
ស្វានឥតខ្សែ
សំណុំក្បាលខួង
ជញ្ជីងវាស់ឌីជីថល ៦ អ៊ីញ
នាឡិកាបញ្ឈប់5
5
A meter that takes the coin but gives no time
A meter that takes the coin but gives no time
Coin-operated timer faults.
Flow
Loading...
6
6
History and honest limits
History and honest limits
**Carl C. Magee** of Oklahoma City filed **US 2,118,318** on 13 May 1935, assigned to the Dual Parking Meter Company; granted 24 May 1938. Oklahoma City installed 150 of his meters along 14 blocks downtown in July 1935, charging five cents an hour; within a few years they spread to cities across the United States and abroad.
**Honest limits.** The notebook's beat rate, train losses and spring figures are illustrative, not Magee's. The printed interlock accepts anything the size of the coin — real meters gauge a coin's diameter, thickness and sometimes its metal.
សម្ភារៈ
5- យន្តការម៉ូទ័រមួលកម្រៃ 10%1 ដុំកន្លែងទុក
- 3 ដុំកន្លែងទុក
- 1 ដុំកន្លែងទុក
- 6 ដុំកន្លែងទុក
- 1 ដុំកន្លែងទុក
ឧបករណ៍ចាំបាច់
6- កន្លែងទុក
- កន្លែងទុក
- 1 vendor sell this, none ship to you yetកន្លែងទុក
- កន្លែងទុក
- កន្លែងទុក
- កន្លែងទុក
ប្លង់ពាក់ព័ន្ធ
ប្លង់ទាំងនេះចែករំលែកចំណេះដឹង — បច្ចេកទេស សម្ភារៈ ឬគោលការណ៍
CC0 សាធារណៈ
ប្លង់នេះត្រូវបានចេញផ្សាយក្រោម CC0។ អ្នកមានសិទ្ធិចម្លង កែប្រែ ចែកចាយ និងប្រើប្រាស់ដោយមិនចាំបាច់សុំអនុញ្ញាត។
គាំទ្រអ្នកបង្កើតដោយទិញផលិតផលតាមរយៈប្លង់របស់ពួកគេ ដែលពួកគេទទួលបាន កម្រៃជើងសារអ្នកបង្កើត កំណត់ដោយអ្នកលក់ ឬបង្កើតកំណែថ្មីនៃប្លង់នេះ ហើយបញ្ចូលជាការតភ្ជាប់ក្នុងប្លង់របស់អ្នកដើម្បីចែករំលែកចំណូល។