Mach III Clutch 98BK, 98BK-ULOW User Manual

Installation & Maintenance Instructions

SENSIFLEX® TENSION CONTROL BRAKES

Patent No. 6,578,691 B1

Catalog Products:

of this brake design

Mach III Technical Support

Email:

Spec sheets and 3D models are available on the Mach III website:

Please contact Mach III to obtain parts list drawings.

This product includes rotating equipment and should be guarded according to OSHA

© Mach III Clutch, Inc. All Rights Reserved

CLICK on product numbers above

helpful during installation.

38BK & 38BK-ULOW

58BK & 58BK-ULOW
78BK & 78BK-ULOW
98BK & 98BK-ULOW

And non-catalog variations

to obtain the product detail sheet

which includes dimensional data

Toll Free: 866-291-0849

International: 01-859-291-0849

[e-mail]

www.machiii.com

http://www.machiii.com/Products/Tension-Control/Pneumatic-Brake/SensiFlex-Tension-Control-Brakes.asp

requirements and other Federal, State and local regulations.

It is the responsibility of the user to provide necessary guarding.

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MOUNTING

HOLES

AIR INLET

DRIVE DISC

NYLON PT.
SET SCREW

NUT

DRIVE HUB

SPANNER HOLES

FRICTION DISC

PISTON

CYLINDER

Reference Diagram:

**IMPORTANT**

Decreasing this gap prevents full disengagement of the brake.

The gap between the friction and drive surface is factory set between 0.010 and 0.020 Inch.

Increasing this gap may result in air leaks and damage to the diaphragm actuator.

This is the ideal clearance for proper performance.

I. Installation

A. SHAFT PREPARATION & MOUNTING

Mach III Clutch products are bored to fit a precision plug gauge for the specified bore size
and should slide-fit your shaft. Make certain that the shaft is free of burrs or nicks. It may
be necessary to file or sand the shaft to assure a slide fit. Never hammer the brake onto
the shaft. Hammering on the brake may cause evident damage or subtle injury that will
shorten the wear life of the unit, and will void the warranty.

1. Apply the anti-seize (E-Z Break) ® lubricant from the packet provided, or equivalent, to

2. Slide the brake over the key on the shaft and tighten the set screws.

3. If the surface that the brake is to be mounted to is absolutely perpendicular to the

4. If the mounting plate is not perfectly perpendicular to the shaft, it is recommended

the shaft.

shaft, use the four (4) flange mounting holes of the brake to insert bolts and tighten to
the machine.

that the brake be mounted using shoulder bolts to allow the brake housing to float. If
the brake is mounted with strain on the bearing, premature bearing failure is likely to
occur.

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Installation (Continued)

Product

Original Thickness

of Friction Disc

Replace When Worn To A

Thickness of

38BK/38BK-ULOW

3/16 Inch

9/64 Inch

58BK/58BK-ULOW

1/4 Inch

1/8 Inch

78BK/78BK-ULOW

5/16 Inch

3/16 Inch

98BK/98BK-ULOW

7/16 Inch

5/16 Inch

Kits Available

Contents

Part Numbers

Facing Kit

Friction Disc & Mounting Screws

38BK-FCGK, 38BK-ULOW-FCGK,
58BK-FCGK, Etc.

Repair Kit

Friction Disc, Mounting Screws,
Spring(s), Diaphragm

38BK-RPRK, 38BK-ULOW-RPRK,
58BK-RPRK, Etc.

B. AIR LINE CONNECTION

Air supply should be both filtered and regulated. Contamination in the air supply will cause
damage to the brake, particularly to the diaphragm actuator. Connect a flexible air line to the
air inlet using a thread sealing compound. Do not use rigid piping. Cycle the brake with
the machine off to assure engagement and release.

II. Operation

Torque (stopping force) is proportional to air pressure. SensiFlex® brakes are designed for use
in slip applications, typically to maintain tension on a web during unwinding or other tension
control applications. Mach III Clutch, Inc. should always be consulted to assist with selection of
a SensiFlex® Brake to assure that required tension can be maintained while dissipating the
heat caused by constant slip.

III. Routine Maintenance

Friction discs are a “wear” item and in a constant slip application, periodic replacement of the
friction disc will be necessary. The frequency of disc replacement varies with each application.
S crews are used to mount the friction disc on the piston. Wear on the friction disc should be
monitored so that it can be replaced prior to the point at which the heads of the mounting
screws would make contact with the face of the drive disc. See following chart for
replacement point recommendations.

Friction Disc Replacement Recommendations

Repair Parts & Services

For parts not included in the kits, please contact Mach III Clutch, Inc. or your distributor.
Factory repair is also available. A return materials authorization (RMA) number must be
obtained prior to sending any unit in for repair. Mach III Clutch is not responsible for products
returned without authorization.

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IV. Repair Procedure

Tools Needed
Hex wrench set
Spanner wrench
Retainer (snap) ring pliers
Flat head screw driver
Scraper (if replacing bearings)

0.010 Inch feeler gauge

Compounds Required
Grease
O-Ring lubricant
Loctite® #609 Retaining Compound
Anti-Seize Lubricant

A. Friction Disc Replacement

Loosen set screws and bolts from flange and slide the brake off of the shaft. Place brake in a
horizontal position with the cylinder facing downward. Loosen nylon point set screw in retainer
nut. Using a spanner wrench remove the retainer nut. Next, remove drive disc which should slide
easily off of drive hub. Inspect the drive surface which contacts the friction disc. Grooves in the
surface would indicate that the friction disc should have been replaced sooner and the heads of the
mounting screws have made contact. This surface must be free from grooves, burrs and foreign
materials in order for the brake to operate properly. If damage is pronounced, please contact Mach
III Clutch or your distributor for a replacement. In addition, the drive disc surface should be
inspected for discoloration (turning blue). If discoloration is present, the unit is being operated
beyond its capacity and Mach III Clutch should be contacted for assistance. To replace the friction
disc, remove brass screws which affix the disc to the piston. Remove the worn friction disc and
make sure the mounting surface is smooth and free from contamination. Mount new friction disc
by snugging all screws using an alternating sequence. Do not over-tighten. If no other
components require replacement, skip to section 3b (Reassembly) for the proper procedure for
reassembling the brake.

B. Diaphragm and/or Bearing Replacement

Diaphragm replacement should rarely be necessary if the air supply is regulated and free of
contamination and if the gap between the friction and drive disc is properly set. Care should be taken
when mounting the brake to insure maximum bearing life. See “Shaft Preparation & Mounting”
for guidelines

1. Diaphragm Replacement

First, follow disassembly instructions above under Procedure for Friction Disc Replacement.
Friction disc can remain mounted on piston during this procedure. Wave spring should be
removed and set aside. Next, turn assembly so that the retainer rings in the air cylinder end are
accessible. Remove innermost retainer ring. Bearing ID is a slide fit on the hub and is affixed to
the hub with a thin coating of Loctite®. You will need to strike the hub or an object inserted into
the hub with a rubber mallet or similar soft face hammer while pulling the cylinder upwards to
break the Loctite® seal. Once seal is broken, remove hub from assembly.

To gain access to the diaphragm remove stud & coil springs, then separate the air cylinder and
piston. Pinch the diaphragm and pull from the grooves which retain it. Make sure that the

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retaining grooves and surface underneath the diaphragm are clean & free from debris.

Lubricate the new diaphragm with an O-ring lubricant such as Dow Corning® #4. Install with the
lips located on the ID and OD of the diaphragm facing downward. Press the lips into the grooves

Diaphragm Replacement (Continued)

by applying pressure while gliding a finger along each perimeter of the diaphragm and then
assure that the lips are fully seated by running your thumb across the surface of the diaphragm in
a clockwise motion several times.

2. Bearing Inspection & Replacement

Check bearing for external damage (missing seal, etc.). Make sure the bearing rotates freely and
smoothly by hand. OD of bearing is press fit into the cylinder. If bearing replacement is
necessary, remove additional retainer ring (at the bearing OD). The bearing should be removed
from the cylinder using an arbor press. New bearing should be pressed back into the cylinder and
outer retainer ring must next be replaced.

If new bearing was not installed, gently scrape away any Loctite® residue from the inside diameter
of the bearing in the air cylinder and assure that surface is clean.

C. REASSEMBLY

1. Reassembly from the point of diaphragm and/or bearing replacement:

Make sure that face of diaphragm is free from debris. Apply a thin coat of grease (such as
Molykote® G-N Metal Assembly Paste) to the polygon shaped I.D. of the piston. Reconnect
air cylinder and piston by carefully lining up clearance holes in piston over threaded holes in
cylinder. Place springs over studs and snug-screw studs into cylinder. DO NOT OVER-TIGHTEN.

Apply a thin coat of Loctite® #609 retainer compound to the inside diameter of the bearing, then
slide the air cylinder assembly over the drive hub. Applying an excessive amount of Loctite® will
make future disassembly more difficult. Replace the inner retainer ring at cylinder end of the
drive hub (outer retainer ring should have already been replaced) making sure that it is fully
seated in the groove provided in the hub.

2. Reassembly from the point of friction disc replacement:

Replace wave spring if worn. Wave spring should be placed over the drive hub and seated onto
the flange located above the studs. Apply a thin coat of grease (such as Molykote® G-N Metal
Assembly Paste) to the hex shaped I.D. of the drive disc. Replace drive disc. Place nut on
threads and tighten using spanner wrench to a point where a 0.010 - 0.020 gap remains between
the friction and drive disc surfaces. It is recommended that a 0.010 feeler gauge be used. Drive

disc member should turn freely after reassembly. If you can feel contact between the friction
and drive surface when rotating, loosen adjustment nut just enough to provide clearance.
Tighten set screw in adjustment nut snuggly when proper clearance has been achieved.

See Installation of Brake section of this document for the proper re-installation procedure.

Technical assistance is available by contacting Mach III Clutch, Inc.

Mach III Product Warranty

http://www.machiii.com/Resources/Warranty-Info.asp

Mach III Clutch, Inc.

101 Cummings Drive ● Walton, KY 41094

Toll free 866.291.0849 ● International 859.291.0849 ● Fax [phone]

[e-mail] ● [e-mail] ● www.machiii.com

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