elesa MM-BL-NK Pneumatic fastening clamps Instruction Manual

OPERATING INSTRUCTIONS
Pneumatic fastening clamps
MM-BL-NK /
MM-BI-NK / MM-BC-NK

Operating instructions

Safety instructions
These operating instructions for pneumatic fastening clamps of series MM-BL-NK /BI-NK/
BC-NK are intended for construction engineers, project developers of plants and machinery, and for installation and maintenance/service personnel.

1.1 Definition of cautions
Caution: indicates a potentially hazardous situation. Failure to observe the safety instructions can cause personal injury or damage to property.

1.2 General cautions
Caution: these operating instructions must be used for all assembly, dismantling, or repair work!

Caution: when in operation, pneumatic fastening clamps of series
MM-BL-NK/BI-NK/BC-NK must be fitted with external safety devices (protective guards, photoelectric barriers, etc.).
Caution: when closed, the pneumatic fastening clamp generates a high clamping force which, remains unchanged even if the compressed air supply is disrupted.

1.3 Intended use, range of application
The pneumatic fastening clamps of series MM-BL-NK/BI-NK/BC-NKare designed for locking mechanical parts to be machined or handled on jigs and brackets.
Caution: before operating the pneumatic fastening clamps (series MM-BL-NK/ BI- NK/BC-NK) make sure that the intended use with regard to the range of use (safety precautions, trained and qualified personnel, compressed air supply) is complied with.

1.4 Product Description
The pneumatic fastening clamps MM-BL-NK/BI-NK/BC-NK are available in the following sizes 20, 32, 40 or 50. The size refers to the piston diameter of the driving pneumatic cylinder. The clamp consists of a pneumatic cylinder, a metal housing with various fitting options and one or two clamping arms. During clamping, the pneumatic cylinder acts as a servo unit on an integrated cam mechanism which triggers the swivel movement of the clamping arms. The rotary motion ends with a mechanical locking action. Operating and switching states can be displayed by means of an external proximity switch.

Safety

Caution: pneumatic fastening clamps are not fitted with their own safety devices. Jamming and crushing hazard! If defective, the pneumatic fastening clamps must not be operated. Maintenance and service work must be carried out with the machine at rest and without pressure applying. After completing maintenance and service work, all protection devices must be refitted in proper working condition.

Assembly and startup

The units are installed or assembled by head using cylindrical screws and guide bushings MM-CC (Fig. 1). The clamp can also be mounted directly to the cylinder by means of the collar clamps MM-SBA (Fig. 2). The mounting surfaces must be plane and clean. All screws must be tightened with the correct torque.

The compressed air supply is connected to the pneumatic fastening clamp using a suitable coupling. The connection marked (+) closes the clamp, the connection marked (-) opens the clamp.
Caution: the pneumatic fastening clamp has an integrated end position damper for the advance stroke, but not for the return stroke. This is why the permissible clamping arm torque must be maintained (see Table). If the recommended values for the maximum clamping arm weight are exceeded, an adjustable end position damper must be used.

4. Querying the operating and switching state
An external proximity switch MM-SI is provided for querying the operating and switching state. It is fitted to the side housing of the pneumatic fastening clamp and the plug is connected to the power circuit.
Operating the unit with an incorrect or excessive voltage can cause short circuits and personal injuries. To ensure correct operation, the maximum ambient temperature must not exceed 80°C. If the ambient temperature exceeds this value, a special sensor must be used.

4.1 LED-Display
Green = the sensor is correctly connected and ready to transmit the signal. Red = the arm is in the locked position. Yellow = the arm is in the rest position.

5. Setting the clamping force
Caution: fingers may be crunched or squeezed when setting the clamping arms. Avoid putting the hands into the operating area of the clamping arms while the clamp is in function. If work is required on the clamp, the compressed air supply must first be disconnected. The clamping force is set by using a special cam mechanism which reaches the maximum clamping force when the clamping position (0°) is reached. A self-locking mechanism of the clamp acts in this position. Once reached, the clamping force is also kept up if the pressure drops.

5.1 Setting the clamping force MM-BL-NK

• Disconnect the compressed air supply to the clamp.
• Tighten the jaw block or the clamping screw to the clamping unit.
•  Other setting steps as shown in the following diagrams:

5.2 Setting the clamping force of MM-BC-NK

| 1 Set the lower clamping screw at a predetermined position. Then place the workpiece.
---|---
| 2 Close the clamp with compressed air or by hand.
| 3 Tighten both the clamping screws of the clamp to the sheet until contact without pressure.
| 4 Open the clamp with compressed air or by hand until it gets to the final position.
| 5 Adjust the clamping screws according to the H value or the rotation angle.
Operating pressure 6 bar 20| 32
---|---
Turn (degrees°)| H (mm)| Clamping force (N)| Turn (degrees°)| H (mm)| Clamping force (N)
0°| 0| 0| 0°| 0| 0
236°| 0,81| 900| 360°| 1.5| 1700
230°| 0,93| 1030| 420°| 1.75| 2050

Once the clamp has been adjusted to the desired force depending on the minimum work pressure the non-reversibility of the clamp should be checked according to to point 5.3 Self-Locking.
5.3 Self-locking
After the desired clamping force has been set in accordance with the minimum working pressure (Table “Operating pressure 6 bar”), check the self-locking mechanism of the clamp.

Checking the bearing cap:
· Remove the side bearing cover on the clamp
· If the clamping arm position (0°) is reached, self-locking acts if
A = 0,5 mm +10

Maintenance

The clamps are fitted with low-maintenance bearings and guides for use in large batch production. It is nonetheless necessary to protect the clamp from dirt. The maintenance interval depends on the ambient conditions and the frequency of use.

6.1 Cleaning

• Remove the cover
• Blow out the clamp from both sides
• Spray mechanisms with a lubricant suitable for needle bearings
• Re-fit the cover

Cleaning the unit with a high-pressure cleaner, dry ice or similar can damage the clamp!
If used under extreme ambient conditions (welding spatter, corrosion, high temperatures, etc.), in particular during arc welding, the clamp must be coated with a special agent (teflon).
The MM-BI-NK/BC-NK pneumatic fastening clamps are not suitable for use in arc welding.

6.2 Compressed air
· We advise using conditioned (filtered) compressed air to prevent particles such as dust, oil or others from damaging the inner components of the pneumatic fastening clamps.
· If a compressed air system with oil lubrication is used, the oil must be mineral-based or synthetic to avoid incompatibility with the grease of the seals.

6.3 Grease for seals
· The commercial grease AR 34-402 is used in all standard pneumatic fastening clamps.
For special executions and for high temperatures, Barrierta L55/1 is recommended.
Both greases are brands of Klüber Lubrication. If you have any further questions, please contact the manufacturer directly.

6.4 Operating pressure
Caution: the operating pressure must not exceed 10 bar! The normal working pressure is 6 bar. This applies to all sizes.
Unlocking the clamp
If the clamping mechanism is situated in the non-reversible position, the clamp will retain its clamping force in spite of the pressure drop. The unit can be unlocked only by again connecting the compressed air supply or manually, with the piston rod of the clamp being pressed down (see illustration).

Caution risk of injury:
If the clamp is unlocked manually, the clamping arm may open suddenly.
For this reason, never reach into the swivel zone.

Replacing the clamping arm

Replace the clamping arms as shown below:

|
---|---
Remove the proximity switches and the lateral cover.| Remove the ball bearings and the pin.
|
Push the shaft down to the end.| Take the internal bushing out of the arm.
|
Unscrew the head by means of two cylindrical-head screws and a wrench| Take the cylinder out.
|
Unscrew the packing ring.| Push down the arm of the piston with a hexagonal key.
Replace the user guide with the new one.

The clamping arms are re-assembled in reverse order:

|
---|---
Replace the two seals of the head.| Place the cylinder bushing according to the drawing.
|
Prepare the shaft with the cylinder bushing and the seal according to the
drawing.| Push the shaft up to the arm and tighten the screw.
|
Screw the head with the help of a wrench.| Push the shaft halfway along the oblong hole of the body.
|
Assemble the internal bushing of the arm with the help of the pin.| Lay the clamp down horizontally and assemble the pin and the ball bearings.
|
Assemble the thermosetting plastic plate and sensor on the clamp.| Turn the clamp and place the bearing in.
Assemble the lateral cover on the clamp.

Function test/Seal-tight test

All pneumatic fastening clamps of the series MM-BL-NK/BI-NK/BC-NK are subjected to the following tests.
8.1 Operation test
To stabilize elastic components, a maximum pressure (10 bar) is applied to the clamps, followed by operation over several cycles.
8.2 Seal-tight test
Working pressure (5 bar) is applied to the chambers of the clamp. The pressure drop must not be greater than 1.5 bar over a period of 8 seconds.
8.3 Friction test
Minimum pressure (3 bar) is applied to the clamp over several cycles and to confirm no undesired burrs or strains are present, no limitation of operation must occur.

Warranty

9.1 Duration
The clamps listed in these operating instructions are warranted for a period of 12 months from risk supply.
9.2 Scope of the warranty
The warranty covers all defective parts of the system and the necessary repairs.
9.3 Limitation of warranty
The following points are excluded from the warranty:

• all damages and defects which are the result of improper use of the system, negligence, overload, unsupervised operation, pressure increase, defective  installation, or extreme causes;
•  all repairs not carried out by our technical personnel;
•  parts subject to wear and tear;
•  damages or defects caused by the standstill of the machine.

EC Declaration of Incorporation In compliance with
EC Machinery Directive 2006/42/EC, Annex II B and its amendments. Manufacturer: Misati S.L., Av. de la Riera, 15, 08960 Sant Just Desvern, Barcelona – Spain. We declare herewith that the partly completed machine, product description Pneumatic fastening clamps MM-BL-NK/MM-BI-NK/MM-BC-NK by virtue of its concept design and its type of construction, and in the version placed on the market by us, complies with the fundamental health and safety requirements of EC Machinery Directive 2006/42/EC. We further declare that the special technical documentation for this partly completed machine has been prepared in accordance with Annex VII Part B and we undertake to forward the documentation upon request to the appropriate regulatory market supervision authority.
The following harmonizing norms and standards have been applied:
EN 12100-1, EN 12100-2, EN 14121-1
Commissioning the partly completed machine is prohibited until the partly completed machine has been incorporated in a machine that complies with the provisions of the EC Machine Directive and until the EC Declaration of Conformity pursuant to Annex II A has been submitted.

The texts and examples were compiled with great care. Nonetheless, mistakes can always happen. The company ELISA S.p.A. can neither be held legally responsible nor liable for lacking or incorrect information and the ensuing consequences. The company ELISA S.p.A. reserves the right to alter or improve these products or parts of them and/ or the accompanying brochures without prior notice.

© Copyright ELESA 2021
Art. Nr. ZDOIU-MM-REV.1
ELESA S.p.A.
Via Pompei, 29
20900 Monza (MB) Italy
phone +39 039 28111
fax +39 039 836351
info@elesa.com
www.elesa.com

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