Difference between revisions of "Frameless Scale"
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*All electrical connections are made with crimp plugs or terminal blocks. | *All electrical connections are made with crimp plugs or terminal blocks. | ||
| − | + | ==Shortcomings== | |
| + | #The M6 Cap Screws stick up and require a spacer or mortising the bottom board (Counter sunk flat head screws?). | ||
| + | #The leveling feet form the over limit protection and are not for leveling. If the are used to level, the over limit protection will break. | ||
| + | #The feet stick out from the rail and can be damaged if dropped or if improperly packed for shipping. | ||
==Material List== | ==Material List== | ||
Revision as of 06:23, 12 October 2014
Goals:
- Parts cost under $100 and are readily available.
- Low thermal drift and creep.
- Low power consumption.
- Overload protection.
- Automatically resumes operation after power failure.
- Can be built by 15 year old student (9th grader) using hand tools.
- No soldering.
- No lethal voltages.
Design Features
- No frame: no welding, no bending.
- Load cells are mounted in metal strut readily available from electrical or industrial suppliers in aluminum. galvanized or painted steel.
- Only straight cuts and drilled holes.
- All electrical connections are made with crimp plugs or terminal blocks.
Shortcomings
- The M6 Cap Screws stick up and require a spacer or mortising the bottom board (Counter sunk flat head screws?).
- The leveling feet form the over limit protection and are not for leveling. If the are used to level, the over limit protection will break.
- The feet stick out from the rail and can be damaged if dropped or if improperly packed for shipping.
Material List
A detailed Parts List with part numbers, suppliers and prices is available in pdf.
Strut is available from different manufacturers with different brand names: Unistrut, Superstrut, etc. It is available in galvanized steel, aluminum, and fiberglass. Closure strips are available in steel, aluminum or plastic.
If the scale will be shipped via UPS or USPS, even though the aluminum is more expensive, it will be cheaper when shipping expenses are considered.
Block Diagram
Enclosures
Several enclosures can be used.
