Group 6 - Toro CCR 2400 E GTS Snow-blower - Gate 1: Project Planning
Contents
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Introduction
This report will provide an organized analysis of the dissection project and a plan for all group processes and tasks. It exists to assess every part of the project and categorize each step of the process with detail. In that same manner we have separated the information into three distinct sections. Section 1 is the Work Proposal which provides an overview of our plan to reverse engineer our product, possible challenges to our progress, and a list of each group member’s capabilities. Section 2 is the Management Proposal which consists of an outline of how the group will approach the workload throughout the project. This includes scheduling meetings, a Gantt Chart to show progress, and roles for group members. Finally, section 3 is Product Archaeology: Preparation and Initial Assessment, which includes a thorough analysis of our product before any dissection has taken place.
Project Management
This section outlines how the group will remain organized throughout the semester including group member roles, preliminary disassembly procedure, group schedule, and conflict resolution plan.
Work Proposal
Capabilities
| Member | Position | Strengths | Weaknesses |
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| Joe Groele | Dissection Specialist |
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| Tyler Salamone | Project Manager |
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| Andrew Lyons | Webmaster/Documentarian |
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| Chris O'Connell | 3D - Modeling Specialist |
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Documentation
To ensure a professional and organized dissection analysis we will take various steps to document all stages of the process.
Notes will be taken by the documentarian concerning the events of each group meeting as well as each lab session. These notes will include ideas, discussions, problems encountered, and diagrams that will aid in our progress. Also, the Gantt chart will be updated by the Schedule Liaison after each meeting to track group progress.
Pictures will also be taken by the documentarian throughout the dissection process. This will ensure a clear visual path taken to dissassemble and reassemble the product.
Tools Needed
To go about properly disassembling the Toro snowblower we will need certain tools. These are the tools we believe will be need:
- Socket Wrench with extender
- Used to remove bolts
- Basic Wrench set
- Used to remove bolts of various sizes
- Piston Ring compressor
- Used to re-attach piston rings to engine
- Snap Ring Pliers
- Used to remove piston rings
- Phillip's and Flat-head screwdrivers of various sizes
- Used to remove its respective screw
- Mallet
- Used to remove stuck casings
- Press
- Used to remove bearings
Frame Work Dissection Procedure
The process will begin with the separation of the product handle from the main body.
1. Dismantle Handle
This will be accomplished through unfastening the bolts and screws which connect the two parts. Another requirement of this stage is unfastening the cord which connects the operation handle to the rotor drive. The next component to be addressed is the snow chute.
2. Remove Snow Chute
This step will also be accomplished by using a wrench to unfasten the bolts connecting the chute to the body. After the chute is removed the side casings are attended to.
3. Remove metal side casings
To do this we would need appropriately sized socket wrenches to remove the bolts which attach the right side casing to the frame. Similarly we would need to remove the bolts of the left side in the same manner with a socket wrench.
4. Remove control panel cover
This task requires that the ignition switch is removed from the inlet to which it is connected. It is also required that the pull cord is disconnected from the crank shaft and internal spring. However this is not an issue since the pull cord was already disconnected upon receiving the product for dissection and analysis. Once this is done, a socket wrench can be used to unfasten the bolts which connect the panel to the frame. From here the only component blocking the removal of the main casing is the gas cap.
5. Remove gas cap
The gas cap can be easily unscrewed by hand. This leads into the removal of the top and back casings which are now accessible.
6. Remove top red plastic casing
This will require an appropriately sized Phillip's head screw driver to remove the screws which connect the casing to the frame in the front.
7. Remove back red plastic casing
Taking off the back casing will require a wrench to unfasten the bolts which connect it to the frame. With the casing removed we will then attend to the auger.
8. Remove Auger
Although we can’t visibly see all of its respective fasteners, we believe the auger can be removed with appropriately sized wrenches and socket wrenches. With this removed the only external component left is the wheels.
9. Remove wheels
There should probably be some sort of fastener to connect the wheels to the axle however there is not. This means the wheels can easily be removed by pulling them off by hand.
This essentially sums up all the external components which can be dissected from initial inspection. The next section addresses how we plan to dissect the internal components.
Internal Component Dissection Procedure
With the internal structure of the snow-blower exposed, there will be several systems to dismantle in order to fully analyze the product. The first we believe we will encounter will be the crank shaft and spring which will connect to the pull cord.
10. Remove Crank Shaft and Pull Cord Retracting Spring
At this point we lack the knowledge pertaining to the tools needed to detach these components. Once the outer casing is removed and the internal components are exposed, we will be able to determine what specific tools and processes will be required. After this we assume that some form of a gear train will need to be dismantled.
11. Gear Train Dissassembly
Again we lack sufficient knowledge as to what tools would be needed to detach this system from the other subsystems. We assume that most of the dissasembly will be able to be accomplished with the use of socket wrenches and screw drivers, but we can not determine the exact sizes or steps needed until we expose each individual sub-system. Once this is complete we will move on to possibly the most complicated sub system, the 2 cycle gas engine.
12. 2-Cycle Engine
Although none of our team members have extensive hands-on engine experience, we believe several tools will be needed. The first instrument we may need is a mallet, in case of a stuck casing. Another tool which may be needed is a pair of snap ring pliers to deal with removing piston rings. A tool which we will need from the machine shop may be a press to remove bearings. We may also need to use a piston ring compressor for when we go about reassembling our product. Our lack of experience may lead us to a request other tool needs which we did not foresee. We will learn of these needs when we reach this step during the actual dissection.
Challenges
This section explains the challenges we foresee hindering the dissection of the Toro snow-blower upon initial examination.
Some of the bolts and screws on the body of the snow-blower have rusted and appear difficult to remove without damage to the product. Also, there is a large number of small components so keeping the parts organized after dissection will be another challenge we must face. Lastly, transporting the machine will be challenging due to its size and lack of structural integrity in the wheels. A third challenge experienced by our group will be the CAD modeling of parts since our team lacks experience in this field. In order to overcome this, we plan to receive help from T.A.s or instructors before submitting our drawings. This way, the documents can be revised and the CAD modelers can continue to learn about how to improve their technique. In the next section, we will discuss our group’s plan to manage the work involved throughout the process.
Management Proposal
This section will describe how our group plans to schedule work meetings, and manage overall project tasks.
Point of Contact
The Group 6 Webmaster may be reached at his University at Buffalo email below.
Andrew Lyons:
- andrewly@buffalo.edu
Meeting Times and Locations
Our Team intends to have a minimum of three weekly meetings. In these meetings we will attend to the specific tasks which are assigned to each member. Our team will meet
- Twice during the week
- We will attend Teusday and Wednesday lab sessions in Furnace 621
- Once over the weekend
- We will work in a group work space in the Greiner Residence Hall on Saturdays
- General Project Check-up
- We will meet for ten minutes after each lecture to review the project status and address challenges, meeting times, or conflicts
For lab work sessions we will work anywhere from 5:00 PM to 8:00 PM since this is when there are T.A. office hours to answer our questions.
Position Responsibilities
Project Manager
- Tyler Salamone
The project manager will be responsible for keeping the team organized as well as making sure the focus of each task remains aimed toward the final goal. He will also negotiate and resolve issues as they arise throughout the process and handle their impact on progress.
Schedule Liason
- Tyler Salamone
The schedule Liaison will ensure that the Gantt chart remains up to date and make any changes to it when needed. He will also organize dates, times, and locations of any and all group meetings.
CAD Modeler
- Applies to all Team Members
A CAD Modeler will assist in the development of CAD drawings for the snow blower components and systems.
Web Master
- Andrew Lyons
The Web Master is responsible for uploading information for each Gate assignment onto the group’s Wiki page. He should be experienced in html programming and be able to constantly update the page when needed.
Dissection Specialist
- Joe Groele
The Dissection Specialist will head operations during dissection in the lab. He will work closely with the documentarian to ensure that the work done in the lab is organized and can be easily referred back to upon reassembly. He will also make final decisions if ever a disagreement arises in the lab regarding dissection.
Documentarian
- Andrew Lyons
Keeps an updated log of events, decisions, and notes made during all group meetings and lab sessions.
3-D Modeling Specialist
- Chris O'Connell
The 3-D Modeling specialist is in charge of assigning components to be modeled to CAD Modelers. He also is responsible for the revision of the work submitted by each CAD Modeler. He may also design parts in CAD when needed.
Gantt Chart
This chart shows the timeline which we will follow in order to successfully complete the gates on time. To do this there are milestones to mark when a task is complete. This indicates when we can move on to the next stage of the process. Click Figure 4 to enlarge the image.
Conflict Resolution
The group plans to handle all conflicts in a mature and orderly fashion. All arguments will be facilitated by the Project Manager and a solution will be decided by the group as to how to resolve the dispute. If we feel one member does not complete their share of the workload we will first try and come to an agreement as a group. This would involve a denial of credit for their share of the work since they did not fulfil their responsibilities. If group discussion fails, we will report to the class instructor for which action to take next.
Product Archaeology: Preparation and Initial Assessment
Introduction
This section provides a thorough analysis of the Toro snow-blower before any dissection takes place. It contains notes and observations that exist to familiarize the group with the product and its systems.
Development Profile
This section will address the development and evolution of the snow blower as well as some key considerations that have impacted the final design of the product.
Design Inspiration
The first device similar to the snow blower was a street snow clearing machine that was designed in 1925. The inventor, Arthur Sicard, was inspired by the way a grain thresher could gather grain and separate the stalks and husks, tossing them away and saving the grain. The same concept can be applied to removing snow from a street or sidewalk. The invention was a four-wheel drive truck chassis and truck engine with an additional engine for blowing snow [1]. The vehicle utilized a rotary auger-like component to collect the snow, similar to the design of the grain thresher. In this way, the snow blower can be considered an adaptive design because the design of the grain thresher was modified to alter its functionality to removing snow.
Early Design and Evolution
Two variant designs of the product have evolved since the Snow-blower's original design. The first type are single stage snow blowers. This design utilizes a single rotor to collect the snow and toss it away through a chute. This is the simpler of the two designs and are quite similar to the early products that were design by Toro, Ariens, and Simplicity in the 1950s and 1960s. The Toro CCR 2400 E GTS being studied in this report is a single stage snow blower. The other design that evolved is the two stage snow blower, which has a similar auger to its single stage counterpart, but also contains a second rotor that pulls the collected snow from above the auger and launches it away through a chute. The two stage snow blower can manage removing larger loads of snow than the single stage designs [1]. This design modification represents further global and societal considerations by offering a more expensive and more powerful alternative to the single stage snow blower that could be used in regions of heavier snowfall and enjoyed by those who were willing and able to pay more for the extra power and functionality.
The Toro snow-blower was designed to be a low cost device intended for personal home use. It’s low weight and maneuverability makes it easier for a woman or teenager to operate the device. The machine is intended to be sold in regions that experience a cold winter season with ample amounts of snow. This excludes areas near the equator that experience non snow fall during the winter months. However, regions with much heavier snowfall are not right for this device because our snow-blower is only designed for snowfall levels of 6-9 inches. Based on these restraints, the primary sales occur in the northern United States, Canada, and northern European nations.
This device was also developed with an emphasis on economic factors. The Toro snow-blower is a smaller, less powerful, yet more affordable machine, when compared to the alternative two stage snow blowers or models that include power wheels. To decrease the purchase price, they took out features like self propulsion and decreased the size of the inlet. These trade offs only mildly affect the product functionality; the user has to push the snow blower, rather than merely steer, and the device is capable of removing a few inches less of snow, but these are specifications that the average user does not require. The Toro CCR 2400 E GTS snow blower still manages to provide adequate capabilities at an affordable price, a reflection of the economic design considerations taken by Toro in the development of this product.
The next section examines the usage of the snow blower and addresses some safety concerns associated with the product.
Usage Profile
The purpose of this product is to remove snow from undesirable locations such as sidewalks, driveways, or paths. The machine breaks up the snow and imports it through an impeller. The snow is then ejected a distance away from the given surface through a snow chute. Finally, the snow blower is intended for home use. This fact can be seen through an analysis of the properties of the machine. The machine’s small size allows for increased maneuverability and easy storage but also compromises how much snow can be removed. A homeowner would not need an exceedingly large machine because they would only be removing snow from driveways or small sidewalks. Also, the small size and decreased weight allow for a larger demographic of users to operate the device.
There are a few important safety concerns that should be addressed, the most prominent being hand injuries that can occur when attempting to clear a jam. The user is often tempted to clear out the jammed snow by hand. If the user clears enough snow out of the way, the auger may begin rotating once again. The user’s hand that was removing the snow may get caught in the auger resulting in potentially serious injuries. This safety concern is addressed by the engage handle which must be held down for the auger to rotate. The idea is that users will release the engage handle when attempting to clear a jam so that the auger should not begin rotating, even once cleared, until the engage handle is pressed down again. Regardless, the U.S Consumer Product Safety Commission reports that about 5,740 snow blower accidents occur each year that result in emergency room documentation [1].
Energy Profile
This section outlines the energy conversions, starting with the translational mechanical motion applied by the user and ending with the rotational mechanical energy that is sent to the gear train and ultimately spins the auger. See Figure 5 for a pictoral explanation to aid in understanding the subsequent paragraphs which further describe the conversions taking place.
By drawing on the pull-start mechanism, translational mechanical energy is created. This cord is wrapped around the crankshaft axle such that when the chord is pulled, the crankshaft is rotated, converting the translational energy to rotational energy. As the crankshaft rotates, it pushes the piston upwards, towards the spark plug, converting the rotation back into translational energy. In the case of the electric start, the spark is supplied directly from electrical power. At this point in the process, chemical energy is introduced to the system in the form of gasoline. The gasoline reacts upon the piston striking the spark plug which provides the initial energy to power the reaction. This chemical energy then continues to drive the motion of the piston due to the great amount of pressure it generates. In this step, chemical energy is being converted into translational mechanical energy. As the piston is being driven downwards, the crankshaft is rotated, which converts the translational mechanical energy of the piston into rotational mechanical energy of the crankshaft. From here, the mechanical energy can further be manipulated to displace the energy to the auger where it can be used to propel the snow.
Complexity Profile
This section segments the operation of the snow blower into five component mechanical systems and one important chemical reaction. The cycle begins when the electric/pull start mechanism is activated.
Electric/Pull Start Mechanism
The pull chord is initially wound around the crankshaft, so that when the chord is pulled by the user, the unwinding of the cord rotates the crankshaft. Rotating the crankshaft in turn raises the piston driving it upwards into the spark plug. Gasoline is introduced to the engine chamber by the fuel injector. The gasoline reacts with the ignited spark and a combustion reaction begins [2]. The pull start mechanism utilizes a spring to retract the pull chord into position after each tug so that it is not dangling in the way during operation. The user may also opt to use the electric start. This action uses an human signal to initiate a spark using electrical energy. In either case, this step is the human signal that initiates the entire process by commencing the combustion reaction until the piston can be driven solely by the chemical explosions in the engine chamber.
The Combustion Reaction
Gasoline is first loaded into a storage container where it is held until required for use. The gasoline is required for the combustion reaction that takes place in the firing chamber of the two-cycle gas engine. The reaction that occurs is shown in Equation 1 below:
This equation shows two moles of octane reacting with twenty-five moles of oxygen in the presence of heat to yield sixteen moles of carbon dioxide, eighteen moles of water, and energy. The two -cycle gas engine of the snow blower provides a practical execution of how this reaction is used to convert the chemical energy stored in the gasoline to expansive boundary work on the piston.
Two Cycle Gas Engine
After the electric/pull start mechanism has been activated and the combustion reaction has begun taking place, the gas and air rapidly expands and drives the piston downwards, represented by the vertical arrow in Figure (6). The energy released by the reaction will continue to cause subsequent reactions continually oscillating the piston in the engine chamber. The translational motion of the piston moving up and down is converted to rotational motion of the crankshaft. An exhaust valve is located on the top of the engine chamber which allows carbon dioxide and water vapor to be expelled.
When the piston is located in its lowered position, air from the surrounding environment is allowed to enter the engine chamber through the air intake valve. This provides a supply of oxygen to feed the combustion reaction and allow the process to repeat. This continuous oscillation of the piston provides a steady rotation to the crankshaft. This rotational energy is sent to a gear train to customize the torque and angular velocity.
Gear Train
The rotational energy that is provided by the crankshaft is not useful to the snow blower’s operation directly where it is generated. A gear train is required to reposition the energy to the auger where it can be used to capture snow. This task is achieved by using a combination of orthogonally oriented gears. If you imagine the crankshaft rotating about the z-axis, a gear could be placed perpendicularly to this gear which could convert the rotation to the y-axis to displace the rotation below the engine. From here, another gear could be used to convert the rotation to the x-axis, the axis on which the auger rotates.
The gear train is also used to adjust the torque f the system. Attaching a smaller gear to the crankshaft will cause an increase in the angular velocity of the system.
Auger
The auger is a spiral shaped component located at the front of the machine, usually made of metal or a durable plastic. The main function of the auger is to collect snow and redirect it to a more desirable location. As the snow blower is pushed forwards, snow is collected into the rotating auger where the spiral shape of the component channels the snow out a chute [4]. The chute can be directed to control which direction the snow is launched away from the machine, completing the task of the machine.
Clutch
Another important component to the snow blower is the clutch. The is not necessarily confined to a certain place in the operation process; instead, it can be thought of as working in parallel to the main system process. The clutch is the component that connects the crankshaft to the gear train and to the auger. When the clutch is disengaged, the two-cycle engine continues to operate without rotating the auger. This allows the machine to ‘idle’ without completely turning the machine off and having to restart the process from the electric/pull start mechanism. The clutch is engaged when the user increases the throttle. This creates a connection between the components, causing the gear train to be reconnected with the rotational energy provided by the crankshaft. As a result, the auger begins rotating once again and collecting snow to be tossed elsewhere.
Component Summary
Overall, there are five main mechanical components in the snow blower, although each component could be broken down further into even more specific subsystems. The various individual components vary in complexity. For example, the electric/pull start mechanism is much simpler than the two-cycle gas engine, which is the primary component and the most complex. However, even the electric/pull start mechanism has a moderate amount of complexity. Simply within that component, there exists a handle for the human to grasp, a string to apply the tension to, a wound connection to the crankshaft which provides the means to convert the pull of the string to shaft work, and a spring to retract the pull chord after each tug.
Another seemingly simpler component of the snow blower is the gear train. It is speculated that this system actually will consist of a complex arrangement of gears to successfully transfer the energy from the crankshaft to the auger. Although the displacement may not be a substantial distance, the torque, direction, and angular speed needs to be adjusted and transferred to the auger were it can be used for the purpose of the process.
The component interaction primarily takes the form of energy transformation from the stored chemical energy in the gasoline to a specific rotational energy at the auger. Each component is a further step in transferring the energy. One component in which the interaction is a bit more complex would be the clutch. This component is essential to connecting the crankshaft and the gear train, as well as to controlling the interaction between these systems and the auger.
The next section will discuss the materials that the Toro CCR 2400 E gts is comprised of.
Material Profile
The materials can be split into two general categories for this profile; visible and concealed.
Visible Materials
Without any disassembling, there are a number of material that are clearly visible. Much of the frame of the snow blower is made of molded metal piping. It is a lightweight alloy and hollow except for at the bends and. This frame comes up from the base of the device and extends at an angle to act as the handlebars. The side casings which house the engine and gear train is also made of a flat molded plate of lightweight metal. There is a portion of metal casing with air holes for ventilating the engine. The wheels are made of plastic and have thin rigid grooved tires designed to support the body of the snow blower as it is pushed along.
The top covering is made of a smooth hard plastic, and the control panel casing is textured black plastic. The control panel displays an array of buttons and switches molded out of solid plastic. There are four primary user interface components on the control panel. The first is the ignition which is a simple plastic turn key. The second is the primer button, which is a flexible rubber diaphragm that takes the form of a push button. Next is the starter which is metal ring to channel the pull start rope into the main casing where it is wrapped around the crankshaft and held in place by a spring. Last is an electric starter button, a smaller rubber push button.
The gas tank is molded out of an opaque plastic, which has a thicker black plastic cap that screws on. The axles are firm steel rods. The pull start mechanism is composed of a t-shaped plastic handle attached to a braided rope. The auger on the Toro CCR 2400 E gts is actually a thick rubber curved ‘blade’ that surrounds a cylindrical metal auger axle. The chute is made from both metal and plastic components and is held together by metal bolts and screws. Similar bolts are used for holding the top and side coverings in place and concealing the inner materials.
Concealed Materials
Although a large portion of the materials are concealed within the outer casings, it is still possible to make assumptions about what types of materials are being used on the interior based on the understandings of the mechanical components that carry out the machine’s function.
Starting with the pull start mechanism, it can be assumed that there is a spring located near the crankshaft to retract the pull string after each pull. For the electric start, there will likely be a battery chamber to provide the electrical spark. Most of the engine components will be made out of metal, including the crank case, crankshaft, and piston. In addition to the engine, the complexity profile predicts a series of gears are contained within the snow blower; axles to mount and rotate these gears must also exist. There must also be an amount of support members and bolts to hold the engine components and other interior structures in place.
The next section investigates the user interaction with the Toro snow blower.
User Interaction Profile
The Toro CCR 2400 GTS snow blower requires a certain degree of interaction from the user. First, the user must start the engine using either the pull cord start or the electric start. This interface is designed to be as easy as possible and does not require a high level of skill or strength from the user. Once the engine is started the auger blades will not begin spinning unless the user is holding down the operation handle which engages the roto drive. Now the user must adjust the chute to determine the direction the snow will be thrown. Once again, this is a very simple process designed to make usage as easy as possible. Finally, the user must actually push the snow blower forward and guide it. This is a relatively small and lightweight snow blower so pushing it is not too difficult in light to moderate snow.
There is also a small degree of of maintenance work required by the user. The most notable and regular maintenance required is the refueling process. The engine runs on a gas-oil mixture so the user is required to create this mixture themselves. once the mixture is made, the user simply removes the cap from the gas tank and pours the mixture in. Other maintenance includes cleaning and removing debris from the auger blades and the chute, both of which are a simple process. It may also be necessary for the user to change the auger blades from time to time as they wear down from use. This process requires the proper socket wrenches and a small amount of labor; however, it is not complicated.
Product Alternative Profile
This section lists three different alternatives to the Toro CCR 2400 E GTS Snow-blower. Table 2 below lists out the cost, advantages, and disadvantages of each option. A picture of each has also been included to give a clear perspective on each alternative.
| Product | Picture | Advantages | Disadvantages |
|---|---|---|---|
| Shovel
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| Ariens Compact 2-Stage
24 in. Gas Snow Blower |
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| Home Plow by Meyer
6 ft. 8 in. Residential Snow Plow |
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Conclusion
This report has described a detailed analysis of how our group plans to dissect the Toro CCR Snow-blower. In Section 1 we proposed an approach for disassembly and assembly and listed the challenges associated with these processes. Each group member was assigned specific roles and an outline for group meetings, work progress, and team milestones was created in Section 2. Section 3 organized the information required to successfully dissect the Snow-blower which familiarized the group with our product. As we approach Gate 2, we have the necessary planning, and information to successfully dissect the product for further analysis.
References
[1] McGill, James. The History of Snowblowers. (2011). eHow. Retrieved October 7, 2011 from http://www.ehow.com/about_5364814_history-snowblowers.html.
[2] Stein, Andrea. How Does a Pull Start Engine Work? (2011). eHow. Retrieved September 21, 2011 from http://www.ehow.com/facts_7729454_pull-start-engine-work.html.
[3] Brian, Marshal. How Diesel Two-Stroke Engines Work. (2011). How Stuff Works. Retrieved September 21, 2011 from http://auto.howstuffworks.com/diesel-two-stroke1.htm.
[4] Explaining the Design of Snowblowers. (2010). Snowblower.com. Retrieved October 4, 2011 from http://www.snowblower.com/articles/explaining-the-design-of-snowblowers-1319.html
[5] Snow Shovel, Orange. (2011). ibexpress. Retrieved October 9, 2011 from https://www.ibexp.com/item/view/id/108742
[6] Ariens Compact 2-Stage 24 in. Gas Snow Blower. (2011). The Home depot. Retrieved October 9, 2011 from http://www.woodsplittersdirect.com/product_info.php?products_id=241
[7] Home Plow by Meyer 6 ft. 8 in. Residential Snow Plow with Patented Auto Angle Feature. (2011). The Home Depot. Retrieved October 9, 2011 from http://www.homedepot.com/buy/outdoors/snow-equipment/home-plow-by-meyer/6-ft-8-in-residential-snow-plow-97512.html
