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FIRST Global Building Guide              Created by REV Robotics 2019, Licensed Under CC BY-SA 

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Figure 18: Shaft Offset Using an Indexable Bracket 

3.3

 

JOINTS 

3.3.1

 

Constructing Joints 

In most cases joints should have at least two sides joined with brackets for strength and stability. Commonly this involves 
taking two of the same kind of bracket and sandwiching the pieces of extrusion (Figure 19), but this can also be two 
different kinds of brackets such as a 90 Degree Bracket and an Inside Corner Bracket installed on the same corner.    

 

Figure 19: Install Brackets on Both Sides of the Joint 

When using brackets to connect extrusion, the joint will be much stronger if the end of the extrusion is beveled (cut at an 
angle) so that the end will sit flush with the face of the adjoining extrusion (Figure 20).   

 

Figure 20: Extrusion with Beveled Joint 

 

 

Summary of Contents for FIRST Global

Page 1: ...FIRST Global Building Guide Created by REV Robotics 2019 Licensed Under CC BY SA fg FIRST Global Building Guide...

Page 2: ...OTORS 6 2 5 SENSORS 7 2 6 BATTERY 8 3 MECHANICAL COMPONENTS 9 3 1 EXTRUSION 9 3 2 BRACKETS 9 3 3 JOINTS 12 3 4 BRACKET ASSEMBLY TECHNIQUES 14 3 5 BEARINGS 16 3 6 LINEAR MOTION V2 19 3 7 HINGES 23 3 8...

Page 3: ...ing to add content to keep making it more accessible for people to build with REV Feel free to pick out specific sections of interest and read those there is no need to consume this document in any se...

Page 4: ...g Android and is where the robot code runs while the Expansion Hub only provides a break out of additional ports Please note that every robot must have one Control Hub but adding an Expansion Hub is o...

Page 5: ...ientation 5V Power Auxiliary 5V power for robot accessories The connector is a standard 0 1 Pitch male header This connector is not keyed so be sure to connect it in the correct orientation Analog Ana...

Page 6: ...and Expansion Hub are keyed meaning that the connector is shaped so that it is not possible to plug the cable in backwards The Servo Motor ports and the 5V Power ports are not keyed and the pin out is...

Page 7: ...oth sides of the Core Hex motor have a Motion Interface Pattern for bolting to any of our motion brackets see Table 2 The Motion Interface Pattern consists of six evenly spaced bolt holes The bolt hol...

Page 8: ...ine Figure 9 A spline is a specific groove pattern cut into the shaft which allows the rotation of the servo motor to be transmitted to the attached Aluminum Servo Horn or Servo Adapter see Table 6 Sp...

Page 9: ...b and Expansion Hub Every I2C slave device has an address a number which is normally fixed by the manufacturer All of the devices on an individual I2C bus must have a unique address so that the master...

Page 10: ...inline 20A mini ATX fuse for protection Figure 12 The battery has a female XT30 Connector This connector is polarized so that the battery cannot be plugged in incorrectly Figure 12 Slim Robot Battery...

Page 11: ...xtrusion and Cross Section Details 3 2 BRACKETS 3 2 1 Bracket Features Plastic brackets are nominally 3mm thick and made from molded nylon PA66 Figure 14 lists key features of the Plastic Brackets for...

Page 12: ...3 Rod End Motion Bracket REV 41 1304 Gearbox Motion Bracket REV 41 1315 Indexable Motion Bracket REV 41 1313 Bearing Pillow Block REV 41 1317 Table 3 Construction Brackets 30 Bracket REV 41 1308 45 Br...

Page 13: ...ength after the ideal angle has been set miter the end of the extrusion which will be connected using the arced slot and drill a hole along the alignment mark arc so that it lines up with the extrusio...

Page 14: ...same kind of bracket and sandwiching the pieces of extrusion Figure 19 but this can also be two different kinds of brackets such as a 90 Degree Bracket and an Inside Corner Bracket installed on the sa...

Page 15: ...s to pieces of extrusion at 90 in the same plane The second is an inside corner bracket is functionally equivalent to the 90 bracket The third type is called a lap joint bracket which allowed to piece...

Page 16: ...e enough exposed thread on the bolt so that the bolt head can slide into the channel in the extrusion 3 Slide the bolt heads into the extrusion slot Note that the bolt heads will only fit if they are...

Page 17: ...matches with the bracket hole spacing 3 Place the bracket on to the protruding bolts 4 Start the nuts on all of the protruding bolts Slide the bracket to the desired final location and tighten the nu...

Page 18: ...desired 2 Tighten the bolt until it feels securely threaded into the hole Leave enough thread exposed that the head can be slid into the channel of another piece of extrusion 3 Slide the extrusion wit...

Page 19: ...ained laterally sideways Short Through bore Bearings are low profile pass through bearings intended to seat directly into any of the motion brackets These low profile bearings have a 3mm contact surfa...

Page 20: ...ugh bore Bearings Figure 33 Pillow Blocks and End Cap Bearings Figure 34 Pillow Blocks and Long Through bore Bearings 3 5 2 Ball Bearings The REV Robotics Building System also uses a metal ball bearin...

Page 21: ...p make creating linear motion on your robot easy The Linear Motion kit contains all the necessary hardware Figure 36 to build a 2 stage lift A 5 5mm Nut driver and 2mm Allen key are needed for assembl...

Page 22: ...Low Profile Socket Cap Bolts x1 M3 Nut x1 Be sure that you insert the bolt from the correct side because the double side slider is not completely symmetric The bolt head should be on the side with the...

Page 23: ...the channel tighten the bolts just until snug OVERTIGHTENING MAY CAUSE SLIDER DEFORMATION AND BINDING The above steps 1 5 will result in the basic building assembly for a linear motion elevator using...

Page 24: ...drive the lift up and down Tapping will make the attachment easier but is not necessary Using a M3 x 16mm bolt and nut driver carefully thread into the end of the extrusion Finish threading with the...

Page 25: ...aged while tightening Figure 39 M3 Hardware M3 hex cap bolts inserted into the extrusion and M3 nylon insert nuts on the outside is the recommended stud up building orientation The stud up method does...

Page 26: ...FIRST Global Building Guide Created by REV Robotics 2019 Licensed Under CC BY SA 24 Figure 40 M3 Drop in Bolt...

Page 27: ...are used to prevent lateral sideways sliding movement of a shaft or a part on the shaft A shaft collar is a hollow cylinder with one more set screws which tighten towards its center and an inner dimen...

Page 28: ...tter to use a shaft collar Table 5 Spacers 1 5mm Spacers REV 41 1325 3mm Spacers REV 41 1324 15mm Spacers REV 41 1323 Spacers and shaft collars are used for the same purpose to constrain components on...

Page 29: ...nment Figure 46 Hex Hub Adapter Mounted on a REV Gear for Added Strength 3 9 2 Servo Adapters Servo Adapters fit 25T spline servos like the REV Robotics Smart Robot Servo REV 41 1097 In addition to th...

Page 30: ...acer changes Figure 47 All Motion Parts Share Common 15mm Part Thickness All Motion components have a M3 bolt hole mounting pattern that is on an 8mm pitch as shown in Figure 48 This makes it easy to...

Page 31: ...has three different traction wheel sizes Table 7 and two different Omni Wheel sizes Table 8 Traction wheels and GRIP wheels are co molded with a polyurethane tread for increased traction 3 11 1 Omni W...

Page 32: ...cs 2019 Licensed Under CC BY SA 30 3 11 2 All Wheels Table 7 Traction Wheels 30mm Traction Wheel REV 41 1353 60mm Traction Wheel REV 41 1350 90mm Traction Wheel REV 41 1354 Table 8 Omni Wheels 60mm Om...

Page 33: ...ne for one rotation of the larger sprocket the smaller sprocket must complete more revolutions so the output will be faster than the input If we reverse the situation and a smaller sprocket drives a l...

Page 34: ...as the very first input gear or the very last gear 2 Starting with the fixed axle then identify all the driving and driven sprockets for any sprockets on that axle One by one loosen these axles slide...

Page 35: ...n and out of the desired outer link or if the chain is already the correct length an accessory called a master link or quick release link Figure 57 can be used to connect two ends of the chain Figure...

Page 36: ...Pliers Master links are used to connect two ends of a section of chain to create a loop of chain In order to use a master link the chain ends should both terminate with inside links Figure 60 Slide t...

Page 37: ...ase the output speed or increase the output torque as shown in Figure 61 but the total power is not affected When a larger gear drives a smaller one for one rotation of the larger gear the small gear...

Page 38: ...Starting with the fixed axle identify all the driving and driven gears for any gears on that axle One by one loosen these axles and slide them until the teeth of both gears are fully engaged and para...

Page 39: ...gth and then the belt ends are connected using a small metal part called a barb The barb is forced into the two ends of the belt to form a loop Belt systems are more prone to slipping than sprockets a...

Page 40: ...bumps on the bottom sanded down and then washers or a custom fit piece of plastic sheet inserted underneath The bolts hold the pillow block and the washers to the extrusion The thickness or number of...

Page 41: ...cket and chain drivetrain Figure 68 In this example the sprockets on the ends are linked to the drive wheels and the center sprocket is driven by a motor not shown Because the driving and driven sproc...

Page 42: ...et This amount of wrap is necessary so that there are sufficient teeth engaged with the chain to transmit the torque Too little wrap 120 and the chain will skip under heavy load while excessive wrap 2...

Page 43: ...n be places parallel to the arm pivot to drive the larger gears Figure 71 Simple Low Torque Arm Example Figure 72 Simple Gear Driven Arm Example 4 3 MINI ROBOT EXAMPLE The mini robot Minibot is a simp...

Page 44: ...nder CC BY SA 42 ALL COMPONENTS 1 1 Scale This section has 1 1 scale drawings for the REV Robotics 15mm Extrusion Building system components Use this list as a reference for part numbers or print the...

Page 45: ...FIRST Global Building Guide Created by REV Robotics 2019 Licensed Under CC BY SA 43 GEARS 1 1 Scale...

Page 46: ...FIRST Global Building Guide Created by REV Robotics 2019 Licensed Under CC BY SA 44 SPROCKETS 1 1 Scale...

Page 47: ...FIRST Global Building Guide Created by REV Robotics 2019 Licensed Under CC BY SA 45 WHEELS 1 1 Scale...

Page 48: ...FIRST Global Building Guide Created by REV Robotics 2019 Licensed Under CC BY SA 46 REV 41 1267 90mm Grip Wheel REV 41 1190 90mm Omni Wheel REV 41 1160 60mm Omni Wheel...

Page 49: ...FIRST Global Building Guide Created by REV Robotics 2019 Licensed Under CC BY SA 47 BRACKETS 1 1 Scale...

Page 50: ...FIRST Global Building Guide Created by REV Robotics 2019 Licensed Under CC BY SA 48...

Page 51: ...REV Robotics 2019 Licensed Under CC BY SA 49 PILLOW BLOCKS 1 1 Scale BEARINGS 1 1 Scale METAL BALL BEARING 1 1 Scale SPACERS 1 1 Scale REV 49 1559 Metal Flanged Bearing REV 41 1528 Round Bearing Inser...

Page 52: ...FIRST Global Building Guide Created by REV Robotics 2019 Licensed Under CC BY SA 50 ADAPTERS AND COLLARS 1 1 Scale REV 41 1147 High Strength Hex Hub...

Page 53: ...FIRST Global Building Guide Created by REV Robotics 2019 Licensed Under CC BY SA 51 PULLEYS 1 1 Scale REV 41 1346 90mm Pulley REV 41 1345 60mm Pulley REV 41 1344 30mm Pulley...

Page 54: ...BRACKETS 1 1 Scale SERVO BRACKETS 1 1 Scale REV 41 1433 Metal Bent Core Hex Motor Bracket REV 41 1487 Metal Bent HD Hex Motor Bracket REV 41 1486 Metal Flat HD Hex Motor Bracket REV 41 1485 Metal Bent...

Page 55: ...53 METAL BRACKETS 1 1 Scale REV 41 1479 15mm Inside Corner Bracket REV 41 1481 Variable Angle Bracket REV 41 1476 30 Degree Bracket REV 41 1477 45 Degree Bracket REV 41 1478 60 Degree Bracket REV 41 1...

Page 56: ...Created by REV Robotics 2019 Licensed Under CC BY SA 54 LINEAR MOTION KIT CONTENTS 1 1 Scale HINGE KIT CONTENTS 1 1 Scale Endcap Double Sided Slider Slider Plate Bearing Cover Left Hinge Center Hinge...

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