Torque Talk

The Ins and Outs of the Industrial Clutch Combination QRV/Rotary Union

April 30th, 2015

The Industrial Clutch combination Rotary Seal & QRV (Quick Release/Exhaust Valve) offers the ability to tune the clutch engagement to meet each presses unique requirements. The Industrial Rotary Seal & QRV is a modular design to fit the complete range of Industrial Clutches used on mechanical stamping presses and many Verson clutches.  The Poppets are a standard part across all configurations with adjustable orifices and there are various cap’s providing several air inlet options.

Industrial Clutch Combination QRV/Rotary Union

Industrial Clutch Combination QRV/Rotary Union

Integrating the QRV into the Rotary Union allows am Industrial Clutch the unique ability to more rapidly exhaust the clutch to reduce “Overlap” with the brake setting during the press stopping, than any other approach.  This operational feature significantly improves press operation by reducing heat in the clutch and brake, while limiting unnecessary wear on the friction material and other parts.

In addition, the poppet orifice diameter can be adjusted by drilling them to a different diameter.  The poppet orifice controls the engagement of the clutch, the smaller the orifice the slower the clutch engages and conversely, the larger the orifice the quicker the clutch engages.  Proper orifice size improves press operation by reducing “Overlap” with the brake when the press is started and providing a smoother clutch engagement.  Under proper guidance, the orifice tuning can be customized to each specific press, providing optimum performance.  The standard for Industrial Clutches is:

Industrial Clutch Orfice Sizes

The operating principle is simple in concept, but often misunderstood, leading to most operating issues.

  • When the clutch is engaged, the supply pressure is higher than the pressure in the clutch, the pressure differential moves the poppet in the rotary union to block the exhaust port while the orifice meters the air to the clutch:
Industrial Clutch Engaging

Industrial Clutch Engaging

  • When the clutch is disengaged, the clutch pressure is higher than the supply pressure, the pressure differential moves the poppet in the rotary union to open the exhaust port:
Industrial Clutch Exhausting

Industrial Clutch Exhausting

A common issue Torque Inc., witnesses, on customer presses, is the QRV is not operating properly.  This issue is caused by the supply pressure from the press safety valve not falling fast enough relative to the clutch pressure when the clutch disengages to create the pressure differential to move the poppet.  There are two primary causes of this:

  1. The poppet orifice is drilled too large, allowing the clutch pressure to exhaust through the orifices at the same rate the supply pressure drops.
  2. The pneumatic plumbing and press safety valve are not allowing the supply pressure to drop fast enough for the QRV to react. The typical installation with this issue has the press safety valve located next to the brake with a very long line to the clutch. With a single press safety valve, the brake exhaust going through the valve prevents the clutch supply line pressure from dropping quickly enough for the QRV to move.

When working with the Industrial Clutch combination Rotary Seal & QRV, a simple check is to feel the exhaust air rushing out of the unit immediately upon the clutch releasing at the end of a stroke.

Torque Inc., Sales Engineers are available to consult with any Torque Inc., customers with questions or issues with these units.  We have the expertise to assist tuning your press for optimal clutch engagement and disengagement.  Please contact us with any concerns, we are happy to be of service.

 

Wichita Clutch on Hurricane Simulator to make homes safer

August 19th, 2013

Mach III Releases EBook ” Make it Last”

April 16th, 2013

Determining how long a friction clutch or brake will last has much to do with application.  Cycle rates, revolutions per minute and the air pressure required to produce the torque to drive or stop the load are just a few of the considerations.  Assuming the unit has been properly sized and the application is not unusually rigorous, the majority of friction brakes and clutches will measure their service life in years as long as the manufacturer’s instructions for installation, operation and routine maintenance are followed.  Mach III has compiled its recommendations for users who want to do all they can to ensure that the clutches and brakes installed on their machinery last as long as possible.  Topics covered in the eBook, Make It Last, include:

  • Proper Selection
  • Regulating
  • Proper Mounting
  • Chain & Belt Alignment & Tension
  • Environmental Considerations
  • Routine Maintenance

Click on: “MachIII_Ebook003 – Make it Last” to down load this helpful guide.

Wichita Clutch introduces expansion of Composite Water Jackets to include WCB style brakes.

April 12th, 2013

Industrial Clutch LK Inspection Checklist

February 6th, 2013

To assist customers inspect and assess the condition of Industrial Clutch “LK” clutches, Torque Inc has developed the “LK-Inspection-Checklist“.  Click on the link to access this helpful aid to ensure all critical parts are inspected during clutch maintenance or repair.

If you have additional questions, contact your local Sales Engineer of our Parts Hot line 800-771-5921.  WE are happy to be of service.

Press Clutch/Brake Hub Mounting Options

November 13th, 2012
There are many methods to mount a Clutch/Brake hub to the shaft of a Stamping Press or other heavy machinery. Torque Inc will help you pick the best type of connection for your application.  The following is a summary of the benefits and limitations of the various methods:

Key with clearance

Using a clearance fit between the hub and the shaft while and hand fitting the key (or two keys) is the most common method. Clearance of a couple of thousandths of an inch with line/line for the keyway is typical. This connection will likely gradually get loose at some point in time, is likely the most common type used on a press.

Key with interference

Adding a slight interference with a hand fit key is a more permanent solution, albeit requiring a modest heating of the hub (to about 250- 300 degrees F through via oil bath, oven or induction heater). Typical fit of line/line to .001”/.002” for shaft size of 6”.

Key with heavier interference

Increasing shrink to .0005” per inch of diameter (ie. .003” interference for 6” bore ) is achievable with a 300-400 degree heat and dry ice of the shaft. This fit is recommended for high shock load/high reversing loads like shears and high stripping force dies, cold forging etc. Care must be taken not to end up with too tight a fit over a key, in that this can cause the hub to split through the keyway. Heavy interference fits are difficult to remove without damaging the shaft/bore interface.

Heavy Interference without key

Using  a .001” per inch of shaft diameter interference (ie. .006”-.009” shrink for a 6” shaft) , or more, can often times gain enough torque to drive without a key or supplemental locking device. However, we do not recommend retrofitting using this method due to the following problems, indluding but not limited to:
1. Precise material specifications are required,
2. Precise machining is required,
3. Installation is tricky
4. Removal does damage to the shaft and hub bore.

The best system is a Engineered Locking Element without a key

Using an engineered locking device such as a Ringfeder, Climax or Bloc creates the advantages of heavy inference shrink fit connection (ie. No backlash ever, removability, ease of assembly and strongest possible shaft and hub design due to no stress risers from keys) without the disadvantages. Some applications are hard to retrofit due to space and material issues. These devices require proper dimensions and installation procedures and torque instruction be followed in order to function properly. However the devices have a 100% success rate when properly engineered and installed (in fact they frequently can carry more torque than the shaft itself can!) .
There are two primary types of keyless locking devices.
Shrink Disc Wichita CCB hub mounting

Wichita Clutch CCB with Shrink Disc mounted hub

The “shrink disc” goes outside of a hub extension and squeezes the hub to the shaft. Advantages are a infinite choice of shaft sizes (ie. Can match any existing shaft assuming it is round and finished properly) and has a relatively high torque rating. Material can be cast iron or steel
Industrial Clutch Hub mounted with Internal Locking Device

Industrial Clutch Hub mounted to shaft with internal locking element.

The internal “locking assembly “ is sometimes easier to fit in (goes inside existing hub) but can only fit a finite number of standard shaft sizes and requires an adequate OD to provide enough strength the keep hub from cracking. Material required to be steel or steel sleeved cast iron.
  • Proper selection of either version of an engineered locking element requires the qualified engineering assistance that Torque Inc. can provide to insure a successful installation.
  • Often the cost of the device is offset by the reduction in labor/machining cost associated with putting a connection together!

Wichita ATD 218 LIHTC on conveyor drive, used as Torque Limiter

October 16th, 2012
Wichita Clutch

Wichita Clutch 224 LIHTC

Wichita Clutch

Alternate view of Wichita Clutch 224 LIHTC installation

Torque Inc Application Engineer Steve Park selected a Wichita Clutch ATD 224 LIHTC (Low Inertia High Torque Clutch) for a custom designed conveyor drive system to provide protection for the drive train elements by functioning as a Torque Limiter. By regulating the air pressure applied to the Wichita Clutch, the end user can accurately adjust the clutch slip torque to a level to allow reliable machine operation under normal conditions and protect the drive train from overload by slipping the clutch,

Assembling a Wichita Clutch, Low Inertia Clutch

June 29th, 2012

A short video showing the process to assemble a Wichita Clutch, LI (low inertia) Clutch.

Disassembling a Wichita Clutch, Low Inertia Clutch

June 29th, 2012

A short video showing the process to disassemble a Wichita Clutch, LI (low inertia) Clutch

Wichita Clutch STVC (standard vent clutch) rebuild guide.

June 28th, 2012

Here is a helpful sheet to show the items to inspect/replace when rebuilding a Wichita STVC Clutch:

stvc-replacement-guide, Torque-Inc

Any questions, contact your local Sales Engineer.  We are happy to be of service.