CM-1K Horizontal Limit Switches with Terminal Cover

Covered snap-action switches for position sensing

CM-1K horizontal limit switches use 1NC/1NO snap-action contacts in a phenolic molding compound body with a terminal cover and tail sleeve. The actuator range includes straight and curved levers, plastic and metal rollers, one-way levers, leaf springs and several plunger geometries. Choose the operating force and travel together with the cam approach and available installation space.

The K cover protects the terminal area but does not make the switch waterproof. Provide suitable external protection from water, oil, chips and dust. These models are distinct from the plain-body CM-1 and other suffix versions.

Ordering structure

CM-1703MK is assembled as CM-1 + 703M + K: standard family, metal roller lever and K terminal protection. There is no separator between these three segments. The hyphen is part of the fixed CM-1 family identifier. Use each complete actuator code, including M or X where present.

Operating characteristics by model

All listed models have 1NC/1NO snap-action contacts. OF is maximum operating force, RF minimum release force, PT maximum pretravel, OT minimum available overtravel, MD maximum movement differential, FP maximum free position and OP operating position. A dash means the value is not specified. Dimensions are referenced to the datums in the attached model drawings.

The needle plunger has only 0.13mm minimum overtravel, so its stop setting needs particular care. Set working overtravel to 70–100% of the rated OT without exceeding the permitted movement. One-way roller assemblies have the illustrated 90° roller swing; this is distinct from the linear PT and OT values.

Electrical and environmental characteristics

These endurance values belong to their stated test loads and cannot be used as one uniform life rating. Verify life under the actual cam speed, switching frequency and load. Very slow actuation can produce unstable switching; excessive speed or frequency can cause impact damage or poor contact follow-up.

Use the applicable model-specific certification documents when approval is required. Specification references and component markings do not establish certification of a complete machine.

Contact load ratings

The 30VDC resistive entry is specified as 6(2)A; the condition represented by parentheses is not defined, so confirm applicability before selecting this duty. The 500VAC general-load entry does not increase the stated 380V insulation rating or authorize operation above the selected model's insulation and approval limits. Apply the contact, load, utilization-category and insulation limits together.

Dimensions and mounting

Use the full model drawings to select the actuator and mounting datum. Some drawings dimension the bare switch body at 49.6×17.6mm; the covered construction is also shown with a 52.8mm housing length, an additional 15.5mm sleeve projection and 18.7mm overall width. These measurements refer to different parts of the assembly.

For side-screw mounting of the panel-plunger models, remove the actuator hex nut as indicated, avoid excessive cam angles and speed, and do not apply shock exceeding 1000m/s². Install a cover where accidental actuation is possible. Keep the switch away from resonant vibration and provide a separate stop so the cam cannot overdrive the actuator.

Terminal connections

Turn off power before installation, wiring or maintenance. Size wiring for the applied current and voltage. Where solder terminals are used, use an iron of at most 60W and limit heating to 350°C for 5s or 380°C for 3s. Avoid prolonged heating and incomplete joints.

For the specified M3.5 crimp-terminal arrangement, use insulated terminals with 0.5–0.75mm² conductors, approximately AWG20–AWG18. Keep terminals clear of the body and cover, use suitable wire lengths and remove all cut wire fragments before closing.

Environmental and contact-use precautions

Prevent chips and dust from accumulating on the body or actuator. Shield the switch from oil, water spray, hot water above 60°C and steam. Avoid outdoor exposure, abrupt temperature changes, corrosive gases and silicone-containing materials that can form insulating deposits on contacts. This switch is not specified for unprotected operation in flammable or explosive atmospheres.

For prolonged low-current or infrequent switching, select a contact design intended for the signal level, such as an appropriate gold-contact version. Standard contacts require at least 24VDC and 10mA; below this level, current may not break through surface films. Do not reuse contacts previously operated at general loads for smaller-capacity signal circuits. Apply suitable suppression to loads that create inrush or contact arcing.

Exceptional reliability, personal safety protection, severe environments, aerospace and military applications require an expressly assessed design. Confirm the selected model's mechanical operation and electrical endurance under the actual installation conditions.