Magnetic rotary switches for membrane keyboards and front panels
Illustration 1: Sample wheel plate: switch wheel (left) and pulser wheel (right).
NOTE: The sample plate shows wheel functions available in the technology offered by the Company.
QWERTY Sp. z o.o., an electro-technological company, has been committed to the design and production of membrane keyboards, front panels and labels since 1988. The company also offers other devices that supplement its range of products, including metal and plastic base plates as well as reinforcing elements for windows and membrane panel displays.
New technological designs developed by the Company have enabled QWERTY to introduce new types of membrane keyboards and front panels with rotating elements, such as wheels and switches. The range of wheels used for membrane keyboards, manufactured by the Company, is described below.
Illustration 2: Sample panel with a dismounted switch wheel and pulser wheel. Set values may be saved when the wheel is taken out.
The following rotating elements can be designed using our technology:
- A pulser wheel consisting of such function elements as membrane switches or a magnetic field sensor, for instance a Hall effect device.
Figure 1: Cross-section of a pulser wheel. As the wheel rotates, the magnetic field sensor detects permanent magnet (2) and generates a logical electric signal.
- A switch wheel consisting of a number of usually closed or usually open contacts, distributed along the circuit. Their operation may be designed individually; for example a contact may remain closed as the next one closes.
Figure 2: Cross-section of a switch wheel. Depending on the position of the magnetic poles, permanent magnets (2) attract or repel permanent magnets (1), mounted on film switches, completing or breaking the electric circuit.
Illustration 3: Back view of a switch wheel with three usually open contacts whose circuit remains closed as the next one closes. The wheel disk with mounted round permanent magnets (2) which, placed under magnetic contact (1), attract it, closing the electric circuit, can be seen under the layer of conductive paths.
Magnetic switch
Technical parameters:
| Specification |
Switch |
Pulser |
| Minimum thickness (H) |
3.5 mm |
4.0 mm |
| Wheel diameter |
Ø > 28 mm |
Ø > 25 mm |
| Guaranteed life expectancy |
2 x 106 rotations |
107 rotations |
| Switch resistance |
≤ 50 Ω |
- |
| Insulation resistance |
≤ 10 MΩ |
≤ 10 MΩ |
| Operation voltage |
max 30 V |
- |
| Switch current |
max 25 mA |
- |
| Ambient humidity |
max 95% |
max 95% |
| Operation temperature |
-40°C ÷ +70°C |
-40°C ÷ +70°C |
| Pitch |
2.54 mm or 1 mm |
2.54 mm or 1 mm |
| Tightness, including dust-tightness |
IP 65 |
IP 65 |
| Vibration resistance |
No |
Yes |
| Holes or openings for securing rotating elements |
None |
None |
| Wheel and front panel design |
as requested |
as requested |
| Saving Settings |
No |
Yes |
Examples:
