PA Notes

PA Notes are technical documents written by the Product Application department that are intended to address particular technical issues or design matters for Gates users and customers.  The very first PA Note, Volume 1, Number 1 was issued on August 29, 1951.   The current PA Note content is up to Volume 57.

Its interesting to look back at that first PA Note and see the content and the state of the art for belt power transmission in 1951.  Topics included in Volume 1, Number 1:

1)  The use of a V-flat drive on a generator.   (When was the last time you designed a flat belt drive?  In fact, when was the last time you saw a flat belt drive?)

2)  Designing a flat belt drive on a turbine application.  (Flat belts were the belt of choice for high speed applications "back in the day".  Now, we would instead design with Micro-V or Polyflex V-belts.   Belt technology has come a long way.)

Consider how long that Gates Product Application has been writing PA Notes - look at the major events of 1951 to place the time in context:

• The Korean War was underway
• The Twenty-second Amendment to the United States Constitution, limiting Presidents to two terms, is ratified
• The first live sporting event seen coast-to-coast in the United States, a college football game between Duke and the University of Pittsburgh, is televised on NBC
• Direct-dial coast-to-coast telephone service begins in the United States
• William Shockley invents the junction transistor

 Its a much different world that we live in, 59 years later.  The world has changed, as has the technology used in belt power transmission.  However, belts still remain one of the most useful, capable, and economical method of transmitting power between shafts.   Today's belts use highly engineered rubber and urethane compounds, a variety of belt tensile cord types, materials, and gages, and in some cases approach having so much power capacity that users can't believe how much power can be transmitted in such a narrow belt.  A far cry from 1951!

 

 

 

Gates Supports over 240 FIRST Robotics Teams

It's the middle of March, and the 2010 FIRST Robotics Competition is in full swing. Gates is a proud sponsor this year's competition, and has provided free customized belt and sprocket assemblies to over 240 teams. All senior FIRST Robotics students who have a robot that uses a belt drive system in a competition are eligible to apply for a $2000 Gates scholarship. More information can be found at www.gates.com/FIRST. The scholarship deadline is April 30, 2010. For information on local FIRST Robotics Competitions near you, please visit http://www.usfirst.org/.

Belt Tension

When installing a belt drive it's critical to apply the correct ammount of tension to the belt for the drive to function properly, but how do you know what tension to set the belt to? It turns out that there is not a universal tension for a belt, but proper belt tension will vary depending on the input power, rpm, and pulley sizes. Tension equations can used to calculate the proper static tension and can be found in Gates Drive Design Manuals. Using Gates free drive design software, DesignFlex or Design IQ, is another way to find out the proper tension for a belt drive. Both programs are available online at www.gates.com/drivedesign.

Belt Drive Design Programs

Design Flex Pro and Design IQ are two belt drive design programs offered from Gates that can simplify the process of designing an industrial belt drive.

Design Flex Pro is used for designing two-point belt drives ( 1 driveR shaft and 1 driveN shaft) and is easy as choosing a belt line, entering in your drive information, and hitting the Design button. DF Pro will then give a list of belt drives that will agree with the input conditions and summarize the information in a Drive Detail Report. This program can only design with stock products offered from Gates.

Design IQ is a more complex program where you can design a Belt Drive with multiple driveN shafts. You can also use idlers and tensioners when configuring the drive. Design IQ gives the user flexibility such as entering multiple driving conditions and implementing non-stock pulley sizes.

Both Design Flex Pro and Design IQ are free programs available to download from www.gates.com/drivedesign

Gates supporting FIRST Robotics

Over the past few years, Gates Corporation has been the proud sponsor of the FIRST Robotics Competition (FRC). The FRC is competition that challenges teams of high school students to create a robot in 6 weeks that can be programmed to interact with other robots to accomplish prescribed tasks against a field of competitors. This program is expected to involve over 45,000 students from over 1800 schools worldwide for the 2010 season. Gates has worked with the organization to help donate belt drive components to the teams as well as provide free engineering support and advice. Gates is truly proud of the work that these students do, and is happy to help support them in this event. To learn more about Gates involvement with FIRST, please visit www.gates.com/FIRST. To learn more about FIRST, please visit www.usfirst.org.

Aircraft Applications

One of the applications that you won't see Gates support is any primary flight related aircraft application.   Sometimes requests to the Gates Power Transmission Product Application department come from homebuilt aircraft builders or designers - they see the weight and performance advantages of a belt drive and would like to incorporate that technology into their aircraft.

Our answer is always "No".   To quote the official Gates policy regarding aircraft applications:

"Primary In-Flight Aircraft Systems:  Do not use Gates belts, pulleys or sprockets on aircraft, propeller or rotor drive systems  or in-flight accessory drives.  Gates belt drive systems are not intended for aircraft use."

Belt inspections will not be able to reveal how much useable life a belt may have left.  While properly designed belt drives are extremely reliable, considering the statistical distribution of belt failures, even a single failure can have catastrophic results in an airborne application.

So - don't use belts on an airborne application.  Don't ask Gates to provide technical assistance for airborne applications.  We'll be polite in discussing the topic with you, but the message will be as discussed above.

Hardware Terminology

In the Power Transmission world, when we talk about "hardware", we're not talking about bolts, screws, or hinges.   "Hardware" refers to the components that the belt runs in.  For the most generic name for hardware we will use the name "pulley" - a common name that most will be familiar with.

The terminology for different products is different for different types of belts.     Let's look at how the different product types have different specific names for "pulley".

For synchronous belts:  "Pulleys" for the current generation of Gates  synchronous belts (PowerGrip GT2, Poly Chain GT Carbon) are referred to as a "sprockets".   "Sprocket" makes the name association with the ability of current products to replace roller chain - and chain's use of the term "sprocket".  Trapezoidal timing belts - the earliest form of synchronous belts, commonly use the term "pulley" to identify their hardware.

For V-belts:  "Pulleys" for V-belts are referred to as "sheaves" (pronounced with the "ea" sounding like the "i" in ship, rather than like the "ee" in sheep).

For Micro-V or flat belts:  "Pulleys" are pulleys!

So - there are really only a couple of exceptions to remember:  "Sprocket" is used for Power Grip GT2 and Poly Chain GT Carbon belt product lines.   "Sheave" is used for V-belt product lines.   For everything else, you're free to call them "pulleys"!