Hydroelectric Dam Gear Couplings - Going the Distance!

Guest Post: Mike Moschella, Lovejoy Canada

On a recent coupling installation at a hydroelectric station in a remote part of Canada, Lovejoy was requested to be onsite. 

I was present to verify that Lovejoy installation procedures were adhered to, as well as to observe an operation sequence of the gates.  The installation was reviewed and operation went as planned, serving as testament to the skill of the crew onsite as well as the detailed installation instructions provided with the FHD 11E Gear Coupling from Lovejoy.

While reviewing the gate hoists, I observed a second Lovejoy coupling – an L050 Jaw Coupling – on the other end of the drum hoist driving a limit switch.  An excellent showcase of the size range of couplings offered by Lovejoy today.

No matter what the industry, remote applications require the same level of service and support from manufacturers.  Despite the remote application being hundreds of kilometers (or hundreds of miles for those of you south of the border) from the Lovejoy Canada office, we recognize the importance of field support during all phases of a project.

About the Author: Mike Moschella has served Lovejoy in Canada both as an IT professional, and more recently as a technical field sales representative. To tap into Mike's rich industry knowledge and experience, please contact him through Lovejoy Canada or reach out to him directly on LinkedIn.   

Highest flexible coupling in the world? (May not be, but it's close.)

At Lovejoy, we take great pride in knowing we are serving customers around the world... "from the deepest mines in the world to the tallest buildings". That's a great saying, but how exactly does Lovejoy back up that statement.

While it's not easy to quickly usher visitors of our world headquarters in Downers Grove, IL (a suburb of Chicago) into a deep underground mine, we can easily take visitors into downtown Chicago where there are some of the world's tallest buildings (and where Lovejoy was originally founded in 1900). Among the many skyscrapers, is Chicago's tallest: The Willis (formerly Sears) Tower. 

On the Willis Tower's 103rd floor (1353 feet or 412 meters in the air) and featuring spectacular views has long stood the tourist focused SkyDeck. In 2009, the SkyDeck completed a renovation that included 4 glass boxes overhanging the city. These 4 boxes, dubbed "The Ledge", were designed for maximum impact and carried the load of the boxes from above visitors' heads, allowing them to feel like they were steeping out onto thin air.

One of the author's first visits to "The Ledge"

While the rails above are often missed and under appreciated by visitors, a second consideration is also often missed... and that is window washing. Because the Willis Tower's window washing system requires windows to be flush with the building, the designers of "The Ledge" had to ensure that the hung boxes could be retracted. 

Anyone who bothers to look up while visiting "The Ledge" will quickly realize that the designers addressed this concern by putting the boxes on rails...which allows the boxes to be repeatedly retracted when the exhibit is closed. (Users may also look down to discover a large mat that is also covering a space used to retract the box.)

Following the exposed rails away from each box will quickly reveal the four power transmission systems designated for the task... and smack in the middle of each is a beautiful Chicagoland (yes' that's what we call the greater Chicago suburb area) beautiful orange banded Lovejoy jaw coupling.

One of the "The Ledge" Lovejoy Jaw Couplings

While we realize there are taller buildings in the world, and we have not taken the time to inspect and certify whose coupling is a top these structures... for us, a Chicagoland company, the Willis Tower is as tall as it gets... and we have been proudly there serving for years.

If you are ever so lucky to be in Chicago and be afforded the opportunity to visit "The Ledge", we highly recommend you look up and take in the full engineering depth and breadth required to provide visitors such a thrill.

Where are couplings used? Check out your backyard!

Uncle's Log Splitter - outside Pittsburgh, PA

To follow on the heels of Bob Buesing's wonderful article and tutorial on log splitter couplings, several weeks ago I was at my uncle's house near Pittsburgh for Thanksgiving. He knew I worked for Lovejoy, and knew that Lovejoy was a leader in industrial flexible couplings of all types and sizes, but he really didn't fully understand what a coupling was or where it was used. 

As luck would happen, my uncle lives on a farm. Given winter is approaching, he had a well-used hydraulic log splitter sitting in his backyard and he had been using it all morning. Well aware that hydraulic log splitters commonly use Lovejoy jaw couplings, I walked out to his log splitter to find a Lovejoy L075 jaw coupling that had been manufactured in Lovejoy's Downers Grove, Illinois facility (where I work!).

The Unsung Hero - Lovejoy's L075 Jaw Coupling

With a Lovejoy flexible coupling application standing in front of us, it was very easy for me to visually demonstrate the need and many benefits that high quality (Lovejoy brand) couplings provide (inclusive of basic concepts to include misalignment handling, vibration dampening, and torque transmission). Should you be looking for a similar primer on couplings, please read Flexible Coupling Basics - A Quick Primer. Should you be looking for a deeper dive into Lovejoy jaw couplings, please read Jaw Coupling Overview - Features & Benefits, Design Basics, and Element Options. 

Now knowing that a coupling from Lovejoy had been working hard for years to keep his family warm for the winter, my uncle left our conversation with a great and deep appreciation for the value high quality (and, in his case "maintenance-free") couplings provide in ensuring reliable and long lasting mechanical power transmission.

While I'm confident that my uncle's Lovejoy jaw coupling will continue to serve him well for years to come, when I left Thanksgiving at his house, I assured him that Lovejoy has hundreds of the coupling he is using in stock... and that it would be my honor to Quick Ship him a replacement should it ever be required! Should you need a coupling fast, please consider using Lovejoy's Quick Ship program through an authorized Lovejoy distributor.

Jaw Coupling Question - "How Much Life Can I Expect Out of the Spider?"

 

A frequently asked question for jaw couplings is: “How much life can I expect out of the spider?”.  The answer to this question is, unfortunately, nearly impossible to determine.  

Spider life is affected by a variety of factors (i.e. high/low temperatures, chemical exposure, operation cycle of machinery, etc).  Lovejoy does provide advice on spider inspection and replacement.  When the spider’s leg volume or thickness is at 75% of the original volume or thickness the spider should be replaced.  Inspection of this can be done visually and will result in disassembly of the coupling only if the spider needs to be replaced. 

Correct installation of a jaw coupling can greatly increase the life and performance of the elastomeric spider.  The installation process starts with the correct coupling selection.  The selection process starts with collecting the proper information about the application.  These factors would include: horsepower, RPM, shaft sizes, the type of driver/driven equipment, type of chemical exposure (if any), and temperature exposure.  After selection, proper installation and alignment are also key factors.

• For installation and alignment instructions: please check out "How to Install a Coupling" or download installation instructions from your favorite coupling manufacturer's website. Instructions should be step-by-step straightforward and speak specifically to your jaw coupling type (straight jaw, curved jaw, spacer jaw styles, and jaw in-shear, etc.)
• To learn more about coupling selection criteria, please check out "Top Ten Factors for Selecting A Coupling".
• For help with calculating required system torque, check out "Coupling Sizing Torque - How to Quickly Calculate (inclusive of Service Factor)".

Jaw couplings are not only one of the most popular and economical flexible coupling solutions in the world, but they also offer a solution that does not need lubrication.  This can be a tremendous time saver, but low maintenance couplings does not mean no-maintenance!  By following the helpful tips above (and two robust articles recommended below), coupling users can ensure that their jaw couplings are in proper condition and avoid unexpected downtime.

Recommended Follow-On Reading: For a robust report on jaw coupling failure analysis, please read: Coupling Failure Analysis - Jaw Couplings (includes hub & spider photos). For a broad overview of jaw couplings in general, please read: Jaw Coupling Overview - Features & Benefits, Design Basics, and Element Options.

Author Credit: This article was written by Charlie Mudra (National Accounts Manager, Lovejoy, Inc.)

Popular Jaw Coupling Option - The Snap Wrap Spider Limits Downtime

Changing out an insert from a jaw coupling can be fairly easy or a time consuming process.  A lot depends on the area around the coupling and the ease of access.  Many customer applications have the coupling placed in a restrictive area, which requires a major effort to dissemble the coupling and change the wearable spider insert.  Sometimes the connecting equipment has to be physically moved so that enough clearance is available to move and flange/hub enough so that the spider/sleeve can be replaced.  This is where the Snap Wrap (SW Type) style spider offers a time saving solution!

The Lovejoy Snap Wrap insert has been part of the Lovejoy Jaw product line up for years, but is sometimes forgotten as a solution to easy element replacement.  The spiders are available in the standard Buna-N material, which gives customers the maximum dampening benefits of all of the spider/insert materials.  This design also provides a fail-safe coupling connection that allows torque to be transmitted a short time even after the spider has failed.  The main benefit of the Snap Wrap is that the collar or snap ring that holds the spider in place can be removed and the spider can be replaced without moving either hub.  This feature allows downtime to be kept at a minimum during spider replacement.

The Snap Wrap spider is available in several popular Lovejoy Jaw coupling sizes from L090/095 to L190.  The torque capacities for the Buna-N Snap Wrap range from 144 to 1,728 in-lbs.  The Snap Wrap design is another example of Lovejoy providing the best coupling fit for every application.  

Note: The Snap Wrap is limited to a max RPM of 1750. For increased speeds of up to 3600 RPM, a similar fail-safe jaw coupling design with a collar attachment is available. This coupling type is called an LC Type (pictured at left), and consists of one standard L Type hub, one LC Type hub (which provides collar attachment), one standard snap wrap center, and one collar with screws. And for a non-fail safe design, consider the Jaw In-Shear coupling, which also make use of two common L line hubs.

Recommended Follow-On Reading: For a more complete perspective on jaw couplings in general, inclusive of a second review of elastomeric spider options, please read: Jaw Coupling Overview - Features & Benefits, Design Basics, and Element Options

Author Credit: This article was written by Charlie Mudra (National Accounts Manager, Lovejoy, Inc.).

Jaw coupling spider materials hold the key to solving customer application challenges

Customers are confronted with a variety of different challenges regarding selecting jaw couplings inserts.  With four different insert materials to choose from, several details about the application should be supplied to offer the best coupling fit.  The amount of existing misalignment is a concern when selecting an insert.  Ambient temperature of the area where the coupling will operate is an important part of insert selection.  The amount of torque a particular spider can handle is also a very important factor in selecting the insert material.  By looking at the different inserts available, Lovejoy can evaluate the advantages and disadvantages of each material and select the best fit for the application.

The standard SOX spider or Buna-N material rubber offers the advantage of vibration damping.  The Buna-N also has good resistance to oil and greater misalignment capabilities than Hytrel and Bronze inserts.  Some of the draw backs to Buna-N are its lack of resistance to certain types of chemicals and having the lowest torque rating of all of the inserts.   

Urethane provides customers with better chemical resistance than the Buna-N material and 1.5 times the torque capacity of the Buna-N material.  However, the Urethane material does not dampen vibration as well as the rubber material.   

The Hytrel insert has the advantage of carrying the most torque of the elastomers.  Hytrel also has excellent resistance to many different chemicals and a temperature rating (250^o F) higher than the Buna-N and Urethane inserts.  However, due to the hardness of the material, Hytrel only offers about half the misalignment of the rubber insert and does dampen vibration.   

The Bronze material insert offers the highest temperature rating (450^o F) and has good chemical resistance characteristics.  Bronze also has a high torque rating similar to the Hytrel material.  The main disadvantage of a bronze insert is that it can only be used in applications running at 250 RPM or lower.   

With all of the these choices available, finding out application’s horsepower, speed, type of machinery to be connected, possible chemical exposure, and ambient temperature of coupling’s environment are critical.

By outlining the strengths and weaknesses of each type of spider material, it is clear that one spider does not fit all.  If this were true, there would be only one spider material.  By considering the application information, the best material choice can be made.  The result is the best fit for the application, which results in longer life for the insert. 

Recommended Follow-On Reading: For a more complete perspective on jaw couplings in general, inclusive of a second review of elastomeric spider options, please read: Jaw Coupling Overview - Features & Benefits, Design Basics, and Element Options

Author Credit: This article was written by Charlie Mudra (National Accounts Manager, Lovejoy, Inc.).