Liberty Massive Mini10/12/2013

Rex Brown

Team Driven #1730

Lee’s Summit High School

Mentor

rbrown1309@gmail.com

For Inspiration and Recognition of Science and Technology

Synchronous Belts (Thanks to Gates Belt for Slides)

Drive Trains (Thanks to Madison Krass & Fred Sayre)

Q&A

Agenda

Gates Rubber Synchronous Belt Drives

FIRST Robotics Applications

FIRST Robotics Competition – 2008/2009

Gates Rubber Synchronous Belts

Benefits for First Robotics Competition

Gates PowerGrip® GT®2 5MM belts are ideally sized for drives and functional applications on a FIRST robot

Lightweight – much lighter than chain and gearing systems for comparable loads

Useful – PowerGrip rubber belt drive systems are ideal not only for drives, but also for linear motion, lifts, game object conveying, positioning, and even for precisely flinging objects

Easy to Work With – aluminum sprockets are easy to machine and belting can be wrapped, cemented, or riveted to structure

Clean – these drives remain clean because oil is not needed and present a complete image of current technology

Quiet – reduced noise as compared with other belt drive technology such as chain and gears

Tooth ProfilesTooth Profiles

PG Timing, Trapezoidal, PG Timing, Trapezoidal, GilmerGilmer

TwinPower TimingTwinPower Timing

(Also available in PowerGrip GT2)(Also available in PowerGrip GT2)

HTDHTD Gates GT, GT2Gates GT, GT2

Gates Synchronous BeltsGates Synchronous Belts

Materials Supplied in 2007Materials Supplied in 2007

Power GT2 Belts

Aluminum HTD Sprockets– Why not GT2 Sprockets

Synchronous Belt DrivesSynchronous Belt Drives

For Comparison Purposes, Let’s give HTD a rated capacity of 1.0 when operating with For Comparison Purposes, Let’s give HTD a rated capacity of 1.0 when operating with HTD sprocketsHTD sprockets

Typical Belt and Sprocket Profile for HTDTypical Belt and Sprocket Profile for HTD

Synchronous Belt DrivesSynchronous Belt DrivesDuring the mid 1990’s, Gates replaced the PowerGrip HTD belt with PowerGrip GT belts, During the mid 1990’s, Gates replaced the PowerGrip HTD belt with PowerGrip GT belts, and continued running with HTD sprockets. and continued running with HTD sprockets.

Typical PowerGrip GT belt in HTD spktTypical PowerGrip GT belt in HTD spkt

Synchronous Belt DrivesSynchronous Belt Drives

PowerGrip GT2 Drive System

Typical PowerGrip GT2 belt and sprocket profile

Application Notes Application Notes

Handling the Belts – Do not bend belts smaller than the diameter of the 15 groove sprocket.

A one time tight bend or crimp will break the belt’s fiberglass tensile member and cause loss of strength and failure of the belt.

Belts can not be joined or spliced by any means other than grooved splice plates with a minimum 6 teeth.

OK! No Way!Drive Alignment - Sprockets must be aligned and shafts

parallel in both planes.

Sprocket Flanges – Provide Flanges either on both sides of one sprocket or one side on the driver and the opposite side on the driven sprocket. All belts drive to one side of the sprocket. You must use flanges.

Guarding & Debris protection – A piece of flat plastic supported in between the belt spans is a simple way to eliminate pinch points and keep debris out of the drive.

Application NotesApplication NotesBelt Tensioning – Tension the belt so that when the drive is under full anticipated load (including shock loads) the belt does not

get slack on one side, or the belt teeth try to climb out of the sprocket grooves. Light load – light pre tension; Heavy load – higher pre-tension. Make sure the mounting structure does not deflect when either tensioning the belt or under operating conditions. If you loose tension, the belt will jump teeth. Keep belt shafts parallel and sprockets in line with each other.

Belt Wrap – Minimum of 6 belt teeth fully in mesh & (60°) belt wrap on the circumference of each sprocket. This will allow a properly tensioned belt to perform at 100% of its load rating. A backside idler can be useful for both tensioning the drive and increasing belt wrap. The idler is used on the slack side of a belt drive. Reversing drive – Idler on either side.

Max “climbout” under load

Too little tension or pulley mounting needs more structure

Product Ratings – Gates belt ratings are set to guarantee long life on industrial applications. For FIRST applications, your load capability is going to be determined by the shaft to sprocket connections, belt wrap, and the ability to pretension the drive so that the belt does not jump teeth. With adequate belt wrap & proper installation tension, you will be surprised by the durability of this product! Load capability of the 09 and 15MM width belts is proportional to their width.

Best advice – One test is worth a 1000 calculations.

Typical 6-Wheel Synchronous Drive

Notes:

•CIM motor primary drive uses 9MM wide belt. Higher torque load on wheel drives uses 15MM wide belt. Front wheel would be 9 or 15 wide depending on loading.

•Rule of Thumb: If using belts for speed reduction, use narrower belts on higher speeds (usually coming from the motor) and wider belts at the lower speeds (powering the wheels)

•Note use of sprocket flanges and belt tensioning points.

•Provide adequate structure to maintain parallel shafts, sprocket alignment, and ability to maintain tension under load.

•Total drive ratio is 7.9 : 1

Telescoping Lift with door motor & 5mm Long Length Belting

Need a reversing drive? PowerGrip Twin Power® belts have teeth on both driving surfaces.

Application Notes1.25” diameter flat rollers with a flange can be used for idlers (either side of the belt.)Make an easy end connection – for 5mm pitch, 9mmwide belting long length belting, make a ferrule from ½ diameter x .035 x 1” Al or Cu tubing. Wrap belting around min. ½” diameter cylinder (to avoid belt cord damage) and insert belt loose ends through ferrule. Crimp the ferrule in a vise. Don’t crimp too tight and you will have a removable connection. Belt Tensioning – note adjustment screws

Robotics Belt Applications

Ball Pitching using opposing belts and a PowerGrip Twin Power belt (teeth on both sides) to reverse rotation. Fast and Accurate!

2 stage, 13:1 ratio positioning drive. Small sprocket on inside of belt span drives a position feedback pot.

Drive DesignDrive DesignDrive DesignDrive Design

Pulley Flanging Requirements– Standard Belts Must Be Restrained On Both Sides– Every Pulley Does Not Require Flanging

15

OK OK OK

Drive DesignDrive DesignDrive DesignDrive Design

Pulley Flanging Requirements– Long Belt Spans May Need Additional ConstraintoBelt Spans > 8X The Pulley Diameter May Exhibit Greater Than

Normal Tracking Forces

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D 8 x D

o Idler Pulleys Can Be Flanged And Used To Constrain Belts As Needed

Drive DesignDrive DesignDrive DesignDrive Design

Pulley Flanging Requirements– Shaft Misalignment Results In Belt Tracking ForceoShaft Non-ParallelismoShaft Deflection

– Synchronous Belts Always Track “Down Hill”

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BeltTracking

BeltTracking

Drive DesignDrive DesignDrive DesignDrive Design

Drive Alignment Requirements

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Ideal Alignment

Parallel Misalignment

Angular Misalignment

– 1/4 Maximum Allowable (Angular + Parallel)

– Shaft Parallelism Influences Belt Tracking

– Shaft Parallelism Influences Belt Tensile Loading

Application: Selecting The Correct DriveApplication: Selecting The Correct DriveApplication: Selecting The Correct DriveApplication: Selecting The Correct Drive

Special Characteristics– Belt Tooth Jumping ResistanceoTooth Jumping Generally Begins At The Entry Point Into The

Driven Pulley– Belt Pre-Tension Is Needed To Prevent Tooth Jumping– Large Sprocket Diameters Reduce Tooth Jumping

oDrives With Short Centers Have Greater Tooth Jumping Resistance Than Drives With Long Centers– Short Belts Elongate Less Under Equivalent Loads

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Application: Selecting The Correct DriveApplication: Selecting The Correct DriveApplication: Selecting The Correct DriveApplication: Selecting The Correct Drive

Special Characteristics Cont.– Belt Tooth Jumping Resistance Cont.oMaximize Tooth Jump Resistance By:

– Designing With A Larger Belt Pitch Drive System– Designing With Large Sprocket Diameters– Increasing Belt Installation Tension– Maintaining Rigid / Non Collapsing Center Distance

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NOTES PowerGrip GT2 part numbers are comprised of pitch, pitch length and width For example, 5MR-400-09 signifies 5mm pitch, 400mm pitch length and 9mm width Belt pitch is the distance in millimeters between two adjacent tooth centers as measured on the pitch line of the belt. Belt pitch length is the total length (circumference) in millimeters as measured along the pitch line. The theoretical pitch line of a PowerGrip GT2 belt lies within the tensile member. 5mm pitch, 9mm wide Long-Length Belting is designated as LL5MR-09. Belting is available in lengths up to 300 ft.

5mm PowerGrip® GT®2 – Belt Sizes Available

Pitch Pitch Pitch

Part No. of Length Part No. of Length Part No. of Length

No. Teeth (In.) No. Teeth (In.) No. Teeth (In.)

5MR-300-09 60 11.81 5MR-575-09 115 22.64 5MR-900-09 180 35.43

5MR-355-09 71 13.98 5MR-580-09 116 22.83 5MR-1000-09 200 39.37

5MR-375-09 75 14.76 5MR-600-09 120 23.62 5MR-1150-09 230 45.28

5MR-400-09 80 15.75 5MR-625-09 125 24.61 5MR-1300-09 260 51.18

5MR-405-09 81 15.95 5MR-650-09 130 25.59 5MR-1450-09 290 57.09

5MR-425-09 85 16.73 5MR-700-09 140 27.56 5MR-1600-09 320 62.99

5MR-450-09 90 17.72 5MR-750-09 150 29.53 5MR-1720-09 344 67.72

5MR-500-09 100 19.69 5MR-800-09 160 31.5 5MR-1755-09 351 69.09

5MR-535-09 107 21.06 5MR-815-09 163 32.09 5MR-2100-09 420 82.67

5MR-565-09 113 22.24 5MR-850-09 170 33.46

No. of Pitch Dia.No. Grooves (In.)

P12-5M-09AL 12 .752

P13-5M-09AL 13 .815P14-5M-09AL 14 .877P15-5M-09AL 15 .940P16-5M-09AL 16 1.003P17-5M-09AL 17 1.065P18-5M-09AL 18 1.128P19-5M-09AL 19 1.191P20-5M-09AL 20 1.253P22-5M-09AL 22 1.379P24-5M-09AL 24 1.504P25-5M-09AL 25 1.566P26-5M-09AL 26 1.629P28-5M-09AL 28 1.754P30-5M-09AL 30 1.880P32-5M-09AL 32 2.005P34-5M-09AL 34 2.130P36-5M-09AL 36 2.256P38-5M-09AL 38 2.381P40-5M-09AL 40 2.506P44-5M-09AL 44 2.757P48-5M-09AL 48 3.008P50-5M-09AL 50 3.133P56-5M-09AL 56 3.509P60-5M-09AL 60 3.760P62-5M-09AL 62 3.885P70-5M-09AL 70 4.386P72-5M-09AL 72 4.511

5mm pitch aluminum sprockets available for 9mm and 15mm wide belts. (For 15mm width, please change end part number from 09AL to 15AL) A complete drive system includes the sprocket hardware, available from Gates as well.

5mm PowerGrip® HTD® – Sprockets Available

Gates sells all products only through our Distributor network. The Gates.com website has this information.

Your best sources that will take credit card orders and expedite delivery are:

B & B Manufacturing, La Porte, IN

bbman.com or 877-787-4022

York Industries Garden City, NY

York-ind.com 800-354-8466

Stock Drive Products- New Hyde Park, NY

Sdp-si.com 516-328-3300

Buying Additional Parts

Download (PDF) your copy from www.gates.com

See URL below, or click through: www.gates.com Power Transmission Catalogs Drive Design Manuals

PowerGrip GT2 – Design Manual

http://www.gates.com/catalogs/index.cfm?requesting=ptcatalog&location_id=524#ddm

The June 2007 GatesPower Transmission catalog is available on www.gates.com

Includes all PowerGrip GT2 components in your kit, as well as all available sizes

http://www.gates.com/catalogs/index.cfm?requesting=ptcatalog&location_id=524#ddm

Gates Industrial Power Transmission Catalog

For additional questions or product-related orders, please email the PowerGrip team at PowerGrip@gates.com or the Gates Product Application Help Line at 303-744-5800

Best of luck in your FIRST competitions! Feel free to contact us before, during, and

after the competition for any questions, opportunities, or inquiries you may have

Contact The PowerGrip Team

SynchronousSynchronousSynchronousSynchronous

•Poly ChainPoly Chain®® GT GT®® CarbonCarbon-- Improved High Performance Belt Improved High Performance Belt Constructed with Polyurethane Body and Constructed with Polyurethane Body and CarbonCarbon Fiber Tensile Cord (approx 15% Fiber Tensile Cord (approx 15% greater capacity than “old” PCGT2). More length stable. More flesible greater capacity than “old” PCGT2). More length stable. More flesible (accomodates back-side idlers well)(accomodates back-side idlers well)

• Pitches Available – 8MPitches Available – 8M• 14M14M