Bulldozer Modules: Table of Contents

Preface: Approach and Bulldozer Design. Collaboration Goals.

Download CAD

​

• Modularity Proofs of Concept
• Bulldozer
• Universal Rotor (Drive) Module
• Round Clamp Module
• Track Module
• Idler Module
• Tensioner
• Lift Arms
• Bulldozer Blade
• 6 Way Blade
• Loading Bucket Modification
• Hydraulic Controls Module (separate doc)
• Universal Loader Arm
• Universal Quick Attach
• Rotation Pivot
• Rotary Module - for blade angle, groundhug pivot, universal rotor mount, 360 degree backhoe
• Swing Module
• ​
• Configurations
• Controls
• Parallel to Series Conversion - for effective use of available power

​

• BOM -
• Size Scalability
• 1 track unit - 112 hp maximum
• 2 track units - 224 hp maximum
• 3 track units - 336 hp maximum
• Universal Drawbar / Quick Attach
• Keyline Plow (another document)
• Offset Rail
• Universal Seeder
• Pipe Layer attachment
• Bale unroller
• Belt spreader
• Compost Tea Injector
• Universal Seeder
• Biochar Injector
• Power Harrow
• Backhoe

​

Modularity Proofs of Concept 1

• Scalability of single MicroTrac from 27 hp to 81 hp on a single set of tracks
• Modular loader arms and cylinders with configurable and reattachable pivots
• Both for arms and for cylinders
• Low and high configurations
• Modular Cab
• Power control range from 27 to 168 hp
• Mountable on front, back, side, top, or anywhere that modular tubing allows
• Can control anything from backhoe, microtractor, bulldozer, etc.
• Modular pivot
• Ready conversion from 3-unit machine to individual units
• Sidecar MicroTrac configuration
• Rear MicroTrac Configuration
• Loader curl-based backhoe
• Extensible backhoe

Super-Wall-e

Base Module

Basic Loader Arm

Modularity Proofs of Concept 2

​

• Adjustable width with space in between for straddling capacity
• Ex. Nut picker, berry picker, or straddling ditches
• Movable cab -
• cab is entirely modular
• can be offset to the side, or mounted elsewhere for reconfiguration
• 3” pivot with modular chain
• Tilt of bulldozer blade
• ​
• 18” pivot
• 360 degree backhoe
• Groundhug pivot for 3rd microtractor
• Super Quick Attach

Modularity Concept 1: Scalability of Base Unit

• Start with base unit
• Scalability of single MicroTrac unit from 27 - 81 hp
• Single set of tracks
• Operator rides behind
• Add driver cab
• Provides safety above 27 hp
• Contains parallel/series drive circuit for 2 speeds
• Cab can control 3 Power Cubes initially
• Scalable to 6 Power Cubes
• Add Power Cubes
• To the side
• To the back

Base Module

2,000 lb + 7,000 lb Torque

3,000 lb + 7,000 lb Torque

4,000 lb + 7,000 lb Torque

54 hp

81 hp

5,000 lb

Cab

5,000 lb

81 hp

Modularity 2: Modular Loader Arms

• Loader arms can be attached anywhere on 3” shafts
• Cylinders have quick couplers
• Cylinder and arm pivots are mounted with modular attachment mounts
• Modular mount of cylinder on arm allows the mount location to be modified readily
• This allows loader geometry to be modified on the fly
• Arms are extensible by attaching extensions using modular tubing
• Quick attach plate is a heavy frame made of modular tubing
• Allows for large implements to be connected, such as a full-sized backhoe

Lift Arms

Cab

​

​

​

​

Lift Arms

Quick Attach Plate

Cylinder

Cylinder

Pivot can be moved anywhere along Cab; attached to frame with U-bolts through tube holes

Modular attachment allows cylinder to be connected anywhere along arms

Detail of cylinder attachment to 3” shaft pivot via clamp. Clamp is identical to other 3” clamps, except for cylinder pin mount

Attachment to Lift Arms is via Stock Bonding Plate

Use stock pivot plate for shaft attachment.

Modularity 2: Modular Loader Arms Cont.

• Attach curl cylinder to the same Stock Bonding Plate as Lift Cylinder
• Strategy: super heavy cylinder (30,000 lb each) controls the Quick Attach Plate, and modules are stacked onto this Quick Attach to achieve up to a 7 way blade plus many reconfigurations including scaling to larger size by trailing of MicroTracs
• Flexible location of cylinder mounts and pins

Lift Arms

Cylinder can be attached to any of the bolt locations

Note: 4” tube must be trimmed at end to eliminate conflict with Quick Attach Plate

Quick Attach can slide up and down the Stock Bonding Plate

Modularity 2: Modular Loader + Quick Attach

• Other heavy duty modules can be attached to the Quick Attach:
• Rotation pivot
• Side-to-side pivot
• Backhoe
• Sides for blades and buckets - high capacity for earth moving or pushing in bulldozer application
• Universal Implement Mount
• 3 Point Hitch with PTO
• For the Bulldozer 7 way blade: application:
• Lift cylinder is used for up and down of blade
• Curl cylinder is used for pitch
• Side to side pivot is used for angle of blade
• Rotating pivot is used for blade tilt

Lift Arms

Modularity 3: Quick Attach Plate

• Third point of development is the quick attach plate
• Must be wide enough for loader arms to attach to outer verticals

• Quick attach plate can be extended, doubled, or modified as needed:
• Universal implement attach for the front
• Universal drawbar attachments
• Bulldozer blade
• Backhoe
• Trailing connection between MicroTrac units
• Connection fo 2 MicroTracs for road grader application

Loader Arm

Side View

Front View

Cylinder and Loader Attachment

Must be wide enough for loader arms to straddle the cab.

Example: Use of loader arms on MicroTrac

Super-Wall-e: a basic microtractor with a supersized bucket or blade. Used for minor grading operations

Modularity 4: Rotation Pivot

​

​

​

Cab

​

​

​

​

​

Lift Arms .

Cylinder

Quick

Attach

Rotation Pivot

Front View

Side-to-Side Pivot

• Rotation pivot has a relatively low profile
• Simplest implementation is a circle cut in a square where the square serves as a form for the rotation
• This has an advantage over industry standards: when angled, the blade can also be pitched (curled)

Back Plate

(½” steel)

1” Distance to the Edge

Plate Cutout

(½” steel)

Latch - welded all around

Rotor

(½” steel)

Quick Attach

Front View of Rotation Pivot

(24” square)

Attachment Plate with ⅛” space underneath

(½” steel)

Attachment Plate has 1” nuts welded into it to allow attachment of further modules

Rotation Pivot is bolted to the Quick Attach with 4 1” bolts

Modularity 4: Rotation Pivot 2

• Rotor is bolted on to the Quick Attach Plate
• Rotation function is thus completely modular
• It could be used on the Quick Attach or between Power Cubes

Front View

​

Bolt pattern allows connection of any intermediary tubes to make connection easy. These holes are really welded in bolts.

Here, this tube has been added for pivot motion with cylinders,for a bulldozer blade tilt application

This configuration can be used for interconnect of 2 Power Cubes to allow ground-hugging

The cylinder attach plates could now function as a connection to another Power Cube - the quick attach is 9 holes wide just like the Power Cube.

Modularity 4: Rotation Pivot Top View

• Rotor is bolted on to the Quick Attach Plate
• Rotation function is thus completely modular
• It could be used on the Quick Attach or between Power Cubes

Top View

Front View

Tractor Construction set Controls Overview

Requirements

• To create a true construction set for heavy equipment, the controls have to be:
• Flexible - capable of controlling various functions and implements
• Multiscale - applicable anywhere from 1 to 100 hp per actuator by both allowing a range of fluid flow (0-40 gpm)
• Stackable - multiple modules may be stacked for higher throughput
• Modular - quick-coupled interchangeable for modification and different use
• Open Source - design explanations allow for time-binding (general semantics) on design effort
• Multispeed - achieves multiple speeds via hydraulic circuit, not gears
• Automatable - designed for 60’ sylvopasture
• Practically speaking:
• To optimize drive system, controls allow for Parallel or Series circuit operation on one.
• This allows for multiple speeds
• Slow mode uses 1-6 Power Cubes with 6 motors in parallel
• Fast mode uses 2 Power Cubes per motor in a parallel configuration

Note: hydraulic design moved to separate document

Control Valve

• Bidirectional: allows forward and reverse flow to the outlet ports
• Must be used with a Power Beyond plug if there are valves downstream. Otherwise, use a return line.
• When Power Beyond is utilized, the return line must still be used from this valve
• However, when Power Beyond is used - only Valve 1 or Valve 2 can be used at a time.

45 GPM

Control Valve

valve 1

Power Cube

valve 2

power beyond outlet

low pressure return to hydraulic tank

valve 1

Power Cube

valve 2

power beyond outlet closed

low pressure return to tank

Selector Valve Circuit

40 GPM selector valve

Controls Overview 2

​

Deployment

• Start with Cab and single Power Cube controlling 2 motors.
• Parallel drive with series valves - allows one speed

Power

Cube

Motor 1

Motor 2

​

• Then rework the system to allow both parallel and series operation of motors

Power

Cube

Motor 1

Motor 2

• broken line shows location of cab

• Selector valves S selects parallel operation just like above, or routes to a new series circuit
• S1 and S2 have to be pushed in tandem to activate the circuit (see circuit detail)

S1

S2

V1

V2

• Each valve, situated on the left and right sides of the operator - is operated by one hand
• Forward and reverse is available
• Pushing one valve forward and one valve back makes the bulldozer spin in place

V1

V2

45 GPM

Control Valve

8 Way Blade

angle

tilt

8 way blade means up-down, pitch (curl), tilt right-tilt left, angle right or left.

• Cat D5 Blade - 9 or 10’ wide, 40” tall
• Cat D6 Blade - 11-14’ wide

• Former OSE work by Leandra

Approach

• To attain modularity and a Construction Set approach core to the GVCS, We follow module-based design using accepted modules, and we are building upon these to make modification easy. Thus, a large number of machines can be built in parallel

Structural Power Cube

Universal Rotor

Erector Set Tubing

Universal Implement Bar

Gasifier

Clamp Modules

Sprocket and Chain

Rotary Pivot

Side-to-Side Pivot

• To eliminate shaft machining, we are using heavy duty clamp modules for attaching rotor implements
• By making the tractor platform highly flexible, we can stack several functions in one pass. Ex: haying for pelletized charcoal making, charcoal injection, compost tea injection, manure spreading, bale unrolling, keyline plowing, rotary hoeing, and tree planting in one pass.

Universal Rotor Clamps

• Existing Rotors on MicroTrac have 3” shaft. Clamp collar has not been used - just a ½” pin through since the rotor shaft was too short for the clamp collar. We can extend existing clamp collar so clamp is on both sides, by lengthening the shaft (welding a 6” extension on one side and 3” on the other)

Universal Rotor

Clamp Module

• Existing Rotors on MicroTrac have 3” shaft. Clamp collar has not been used - just a ½” pin through since the rotor shaft was too short for the clamp collar. We can extend existing clamp collar so clamp is on both sides, by lengthening the shaft (welding a 6” extension on one side and 3” on the other)

Concept: using clamp collars instead of drilled pin holes or milled keyways allows for high torque connections for wheels and other components allowing for rapid disconnect and for elimination of shaft machining.

Universal Rotor 2

Build Instructions:

​

• Cut [2] 6” section of a 3” shaft on bandsaw
• Cut [4] 3” sections of 3” ID DOM Tubing
• Cut DOM section in half lengthwise with #0 tip (½” Wall DOM)

3” shaft

1

2

1

2

3

Universal Rotor 3

3” DOM

3” long [2]

3

Concept - but with wing clamps on both sides

wing

2”

3”

Cut wings from ½”x2” stock

​

​

4

4

5

5

Weld wings to tubing halves

5.5

Use shaft as mold, and bolt these together using a 3/16” spacer

5.5

Keyway Clamp

5.5

Universal Rotor 3

6

Concept - but with wing clamps on both sides

3” Shaft

3” shaft

sprocket

Weld winged halves to the sprocket piece while clamped down on shaft. Weld one half of the clamp so the top part of clamp can still be unbolted.

4000 lb of torque from this system. Bolts must hold 10,000 lb of torsion. Ok here, but not much more scalable.

Clamping Calculations for 3” Clamp Collar

wings

2”

3”

• Clamp strength of 1”-8 tpi bolt is 38k lb, with 53 ft-lb tightening torque
• Clamb strength of a ¾”-10 G8 bolts is 30k lb - so 4 of them per sprocket are 120k lb clamp force
• This source indicates a coefficient of friction of .15 for cleaned mating surfaces, thus resulting in 18,000 lb of hold. We need 10,000 lb of hold.
• This source says coefficient of friction for steel is .5-.8, resulting in at least 60k lb of holding force

¾” bolt hole

Concept - but with wing clamps on both sides and two ¾” G8 bolts instead of a single 1” bolt

3” shaft clamp collar

Bulldozer Proper

Track Chain

Module

Power Cube

Deadweight

Module

Lift Arms

Blade

Control Module

Lift Arms

Universal Drawbar

Idler Module

Drive Module

Clamp Module

Ardupilot Module

Connection Module

Track Tensioner Module

Rotary Pivot Module

Swing Module

Swing Module

Modules Prior Art - OSE

Builds upon Concepts:

• OSE Specifications
• Global Village Construction Set
• LifeTrac Construction Set
• Universal Rotor Construction Set
• Construction Set concept

​

Builds Upon the Proofs of Concept of Several Modules:

• Structural Power Cube - a Power Cube with a structural frame that allows the Power Cube to be used as a self-contained module
• Modular Wheel Units, which are an instance of the Universal Rotor
• See 3 types of Wheel Mounts
• See 3” Wheel Hub
• Structural Modular Tubing - 4”x4” square tubing for structures, either ½” or ¼” wall - and its scalability by using multiples
• Power Cube Scalability. To date, we have used up to three 28 hp Power Cubes, or as little as a single 1 hp Micro Power Cube to drive a 5000 lb tractor
• Scalable Pivot Joints and stock plates (bonding + pivot plates)

Configurations

Cab

power cube

power cube

tracks

tracks

56 hp

• +direct scaling of Base Unit
• +acceptable axial torque
• +fully scalable

Cab

power cube

power cube

tracks

tracks

power cube

power cube

tracks

tracks

Fully Scalable Version - 112 hp+

• +direct scaling of Base Unit
• +acceptable axial torque reduction

4,000 lb min + 6000 lb Torque

7,000 lb min + 12,000 lb Torque

power cube

tracks

tracks

Base Unit - 28 hp

• -slow speed -no cab
• +smallest unit
• +efficient shaft use
• +parallelizable
• +scalable to 2 wide + 2 deep
• 2000 lb base scalable to 8000 lb

2,000 lb weight

8000 lb drive Torque

Cab

power cube

power cube

tracks

tracks

power cube

tracks

tracks

tracks

tracks

7,000 lb min + 18,000 lb Torque

Fully Scalable Version - 84 hp+

• +direct scaling of Base Unit
• +acceptable axial torque reduction

Configurations 2

power cube

power cube

power cube

Cab

power cube

power cube

tracks

tracks

power cube

tracks

tracks

tracks

tracks

7,000 lb min + 18,000 lb Torque

Fully Scalable Version - 84 hp+

• +direct scaling of MicroTractor
• +acceptable axial torque reduction

Cab

power cube

power cube

tracks

tracks

power cube

tracks

tracks

tracks

tracks

16,000 lb min + 18,000 lb Torque

Fully Scalable Version - 168 hp+

• +direct scaling of Base Unit
• +Dead weight is removable
• Heavy structural cab is 2000 lb
• Blade is 3000 lb
• Keyline plow is 2000 lb

Base Bulldozer

universal implement attach

​

7 way blade

​

7 way blade

​

universal implement attach

​

Cab and Dual Positions of Attaching Main Lift Cylinder for Low and High Reach

Cab

​

​

​

​

Low Cylinder

Blade

Swing Module

Cab

5’ tall

​

​

​

​

Lift Arms .

Rotary Pivot Module

Lift Arms

Quick Attach Plate

Cylinder

Cylinder

Square Clamp

rotation

Low Cylinder

High Cylinder

High Cylinder

3” shaft u-bolted to top and bottom (or elsewhere) of frame so loader or cylinder can be attached to this 3” shaft. This way, the cylinder or loader can also be attached at the top or bottom as needed for high lift or low lift configuration.

MicroTrac Bolt Conflicts

open if battery box is moved

Red arrows show available holes

Backhoe

Past work - link - this has been built, but side to side pivot does not work well. Too tight geometry.

• Current improvement needed is side-to-side pivot like this using chain and cylinder (same chain as bulldozer tracks)

Cheap Fuel and Expensive Operator 101

Any info on whether the middle tracks are free/idle? It has to be moving, as otherwise, they could use a single dozer with a 2x wide blade. It’s about traction.

Image source

cab

microtrac

microtrac

microtrac

Motion Considerations: inner tracks slide on ground when turning. This is where their axial thrust resistance allows them to do so. Axial thrust rating of bearings is 36,000 lb using the 3” bearings.

Want to stay at 8 for road legal and manaeuverability reasons.

pivot point, actually, i’m not even sure where the “pivot point” is considering the front microtrac

The part in red will be gliding sideways on dirt like a shovel.

Exactly. That’s what happens when a skid steering machine like this turns. There will be large forces. Force expected with a unity coefficient of friction is equal to the weight. That weight is 8k lb for each microtrac section. I’m not saying this is ideal or even good. But it’s an acceptable price to pay for 100% modularity. It’s a tradeoff for modularity. Nobody does this primarily becuase they are not building 100% modular devices, AFAIK.

front cube also will get dragged.

microtrac

microtrac

Row Straddling Considerations

Modularity of drive units allows row-straddling machines when a space is opened between the front microtracs so you can straddle rows, for example to make this into a hazelnut picker or blueberry picker or a dual-sided bale unroller.

Collaboration Goals

Imagine when at any time - there is a crew of people working collaboratively on a document 24/7. The potential of online mass collaboration has hardly been tapped. What does it take for OSE to achieve this?

Collaborators working on this document

Series Operation of Motors

Power

Cube

Motor 1

Motor 2

1

2

A

B

C

D

45 GPM

Control Valve

40 GPM Selector Valve

In series operation - ports P1 and P2 of the selector valve are used. Fluid at point 1 goes to port A of Motor 1. Fluid cannot skip Motor 1 and flow through point 2 and 2’ because of check valve C1. Therefore, fluid enters motor at port A, spins the motor, and exits out at port B. From there, the fluid cannot bypass Motor 2 and flow through 4 because port P4 is closed on the selector valve, nor point 4’ because of check valve C2. Fluid from 3 cannot go through 2’ because 2’ is at higher pressure (‘uphill’ from C). Thus, the only way that the fluid can flow is through Motor 2 to D and then to P2. The path 4’ cannot be taken because 4’ is ‘uphill’ from D.

​

This Series pathway is reversible - pending use of additional check valves C3 and C4 according to an extension of the reasoning above. This is all good...but… the parallel route does not work as is...

P1

P2

P3

P4

3

C1

2’

4

4’

C2

C3

C4