Group 6 - Toro CCR 2400 E GTS Snow-blower - Gate 2: Product Dissection

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Contents

Introduction

While Gate 1 set the stage for the dissection of our product, this Gate provides detailed information regarding the process and analysis of the disassembly of the Toro Snow-blower. In the sections below, detailed lists quantify the inner components of the Snow-blower. Also, a step-by-step analysis of the process to dissect the machine addresses the location of parts and their difficulty of removal. Furthermore, information gathered during the dissection of our product is used to form conclusions about the subsystems that operate within the machine. The rationale of the Toro design team behind their decisions for the interactions between subsystems is also addressed during this analysis. This report creates a detail-oriented foundation to broaden the understanding of how the product works and provide a smooth transition into further analysis of the machine in later gates.

Preliminary Project Review

Project Assessment

Work Proposal

Our work plan in Gate 1 stood as an estimation of how we would dissect the Snowblower. This included tools needed, capabilities of each group member, possible challenges, and the sequence of dissection. Although this gave an accurate prediction of the dissection process, we deviated from this plan in a few areas.

1. Several tools listed in the Work Plan were not used during the dissection

  • Piston Ring Compressor
  • Rubber Mallet
  • Press
  • Snap Ring Pliers

2. The order of disassembly does not follow what steps we took during dissection. This can be attributed to a lack of knowledge of certain parts that impede the removal of others. A few examples include:

  • Metal Side Casings: We were not able to remove these when we planned because the arrangement of the gas tank and multiple connections to inner subsystems.
  • Crankshaft: Although stated as the first component to be removed in our Internal Component Dissection Procedure, the crankshaft was the last part to be removed due to its multiple attachments to outer subsystems.


The Work Proposal listed possible challenges we may face during the dissection process. One of these challenges proposed concerned organization throughout the dissection due to the number of small parts. In order to ensure a successful reassembly, the parts and systems must be stored in a way that it will be simple to find where they go and how they are to be oriented. In order to resolve this problem our Documentarian, Andrew Lyons, labeled plastic bags and placed parts of the same subsystem in each bag. Also, labels were placed on various bolt and screw holes on parts so that the group is aware of what size bolts are to be used for the reassembly of that part.

Management Proposal

This section will discuss the successes and failures of our management plan throughout the course of Gate 2. This management plan, created in Gate 1, organized group meetings, assigned roles to team members, and discussed how to resolve possible conflicts. Although it worked well in many respects during Gate 2, we encountered problems that our management plan did not account for. During the dissection of the Snowblower, lab space became congested as multiple groups worked in the small lab in Furnas Hall. This led to a shortage of available lab materials and work space which put a strain on our overall productivity. Our management plan did not account for this issue since it only addressed team meetings and not the optimum time for lab work. To account for this we spent additional time in the lab to complete the dissection.

One aspect in which our management plan worked successfully was the organization of team meetings. After each lecture, we had a small meeting that assessed progress so far, and what still needed to be completed. Also, we were able to dissect our machine ahead of the lab deadline by organizing lab times in team meetings. Lastly, through our point of contact Andrew Lyons, we were able to keep in touch with instructors and T.A.s when questions or concerns about the project arose.

Each group member assumed a role that led to the efficiency and quality of the dissection process.

Chris O’Connell and Tyler Salamone
  • Both members performed the main hands-on work of disassembling the Snowblower.
Andrew Lyons
  • Andrew performed the documentation of each step in the dissection process including taking pictures, typing specifications of each part removed, and organizing all removed parts with labels and plastic bags.
Joe Groele
  • As the Dissection Specialist, Joe oversaw the entire process and provided guidance to both the hands-on and documentation roles as well as participating actively in both.

These assigned roles ensured each group member could apply their experience during work in the lab. This allowed team members to work on tasks most suited to their individual strengths and led to a reduction of work time. For example, Tyler Salamone and Chris O’Connell were assigned a hands-on roles because of their experience with Snowblowers and various tools in a shop.

Unresolved Challenges

A few challenges encountered by the team remain unresolved:

1. During dissection, a large number of roller bearings fell out of the bracket member on the crankshaft.

  • To resolve this, we plan to receive aid from an instructor in the Jarvis Hall machine shop when we need to re-insert these parts into the Snow-blower.

2. While we attempted to remove various parts, loose washers and nuts would fall out of the Snowblower and leave us with no knowledge of where they came from. For example, during our removal of the top red casing (Step 4), 2 washers fell out of the Snowblower. This occurred again while removing the control panel as a random screw fell out of the machine. In both cases we had no idea where each part came from.

  • In certain places on our product, we noticed missing components so when we reassemble the Snowblower, we plan to match each “random” part that fell out to these areas missing parts.

Product Archaeology

Product Dissection

This dissection procedure provides step by step instructions on how to disassemble the Toro 2400 E GTS snowblower. The procedure is split into eighteen main steps, each focusing primarily on a certain subsystem, or part of a subsystem. Each step will be begin with a list of the tools required, the ease of disassembly based on our created difficulty scale, and a time estimate that provides an approximation of the amount of time it should take to complete the step. The procedure is located beneath each brief opening table; it describes what the user should do and which tools to use. Lastly, each step will include a section called ‘Intent of Disassembly’ which considers whether the part of the product was intended to be disassembled and supports the decision with a short discussion of the supporting evidence.

Provided below is a link which shows the entire parts list for the Toro Snowblower.

Group 6 - Gate 2 - Parts List

Explanation of Difficulty Scale

We decided to use a numeric scale ranging from 1 to 5 with 1 being the easiest and 5 being the most difficult.

Factors that affect difficulty include:

  • number of tools used
  • amount of time required
  • amount of skill required
  • number actions to complete step
  • physical strength required
  • number of people needed

Examples of Difficulty Scale:

(1) - A difficulty of a 1 indicates that one person with no prior experience could easily and quickly complete the step with minimal to no difficulty. The tools required for this step will be basic and simple to use such as a wrench or screw driver or the users hands.

  • ex) The removal of the gas tank cap by hand.

(2) - A difficulty level of 2 may take more time to complete than a level one and may require one or more tools to complete the procedure. The tools required for this step will be basic and simple to use such as a wrench or screw driver.

  • ex) The Removal of Phillips head screw from electric motor assembly.

(3) - A difficulty level of 3 represents a moderately challenging step. This may require an additional member to assist in the process or a larger force to perform the task. In addition, it may require some prior knowledge; but the tools used are still basic.

  • ex) The removal of nut-bolt pair between engine surface requiring 2 group members.

(4) - If a step is given a difficulty level of 4, it requires multiple members of the group to complete the task as well as an advanced level of skill or experience on the part of one member to complete the task. The tools required to complete the process are less common and require higher skill to operate.

  • ex) Removing a rusted nut from between auger connection and the side panel. It would be difficult to get to and require significant force to loosen.

(5) - A difficulty of level 5 indicates a task that requires the assistance of a professional to complete it. The functions and tools involved are beyond the skill level of the students involved.

  • ex) Use of a mechanical press to remove piston rings.


Through out our dissection process, the majority of the steps were in the 1-2 difficulty range with the most difficult step being a 3.

Step 1: Handle Dissection

Time Estimation: 5 minutes

Table 1: Handle Dissection
Sub-Step # Image Difficulty Instruction
1
CC
Figure 1: Detach engage cord from engage handle and pulley chamber bracket
1
Detach engage cord from pulley brace to engage handle
2
CC
Figure 2: Detach engage handle to upper handle
1
Detach engage handle to upper handle by hand
3
CC
Figure 3: Detach lower handle from upper handle
2
Detach upper handle from lower handle using 3 bolt-nut pairs and 1 eye-hook and nut pair using a 13mm wrench
4
CC
Figure 4: Detach middle of lower handle from frame
3
Detach middle of lower handle from frame by removing 2 bolt-bearing-washer-nut pairs using a 13 mm ratchet
5
CC
Figure 5: Detach bottom of lower handle from frame
2
Detach bottom of lower handle from frame by removing 2 bolt-washer pairs using a 13 mm wrench


Intent of Dis-assembly:

It seems that the handle was not intended to be frequently taken off, but the screws were easily accessible so that the owner could have the option of removing it. This makes sense for storage purposes since the handle significantly adds to the required storage volume. It takes only about five minutes to unscrew and remove the handle bar.

Step 2: Chute

Time Estimation: 12 minutes

Table 2: Chute Dissection
Sub-Step # Image Difficulty Instruction
6
CC
Figure 6: Detach Chute top from chute shaft
2
Detach chute top to chute shaft by removing 2 bolt-nut-washer pairs using 13mm ratchet
7
CC
Figure 7: Detach Chute shaft and handle
2
Detach chute shaft and chute handle from chute base by removing 3 bolts using 11mm wrench


Intent of Dis-assembly:

Similarly to the handle, the chute was designed so that it could be easily removed with the help of a half inch ratchet. This could aid in storage efficiency as well as provide an access route for clearing out an ice blockage.

Step 3: Gas Cap

Time Estimation: 10 seconds

Table 3: Gas Cap Removal
Sub-Step # Image Difficulty Instruction
8
CC
Figure 8: Gas cap
1
Unscrew gas cap by hand


Intent of Disassembly:

The gas cap was assuredly made to be removed easily. The user needs to be able to refill the gas tank on a regular basis.

Step 4: Casings

Time Estimation: 15 minutes

Table 4: Casing Removal
Sub-Step # Image Difficulty Instruction
9
CC
Figure 9: Remove casing assembly from body
2
Remove the casing-control panel assembly from the body using 2 Phillips head screw-washer-nut pairs and 2 bolts with a 12 mm wrench


Note:

During this step, two rogue washer components fell out from inside.

Intent of Disassembly:

The red casing was designed to be taken off when the owner desired. It only requires a Phillip’s head screwdriver, and then the main casing can be rotated back to reveal the inside of the snowblower. This provides the user with an ability to take a look at the engine of the snowblower without entirely removing the rest of the casing.

Step 5: Bottom Plastic Flap

Time Estimation: 5 minutes

Table 5: Bottom Flap Removal
Sub-Step # Image Difficulty Instruction
10
CC
Figure 10: Detach bottom casing to body
2
Turn assembly on its side and detach bottom plastic flap by removing 2 nuts using 11mm wrench


Intent of Disassembly:

This step required the snowblower to be turned over and the screws were less convenient to access. For this reason, this piece was probably not intended to be removed, but if engine maintenance was required, this flap could be removed to expose the engine further, although the easiest route get to the engine is through the top, rather than through the bottom.

Step 6: Casing

Time Estimation: 20 minutes

Table 6: Casing
Sub-Step # Image Difficulty Instruction
11
CC
Figure 11: Connecting top casing, control panel, and back casing
2
Detach top and back red casings and control panel by removing 2 bolts with an 8mm ratchet
  • Note: It is expected that these bolts are missing nuts.
12
CC
Figure 12: Black ventilation casing attachment
2
Detach black ventilation casing from top red casing by removing 3 bolt-nut-washer pairs using 8mm wrench
13
CC
Figure 13: Detach case brackets from top red casing
2
Detach plastic and metal case bracket from top red casing by removing 8 nuts using an adjustable wrench


Note: During this part of the dissection, one screw fell out from somewhere inside the engine cavity.

Intent of Disassembly:

Although the control panel was designed with external screws, the electric start cable is wired to the engine, causing the control panel to be challenging to remove without taking it off with the main red snowblower casing. Even if it were easy to remove the control panel individually, this would not result in a significant advantage to inspecting the engine because the opened slot would not be large enough.

Step 7: Auger

Time Estimation: 20 minutes

Table 7: Auger
Sub-Step # Image Difficulty Instruction
14
CC
Figure 14: Removing pulley chamber cover
2
Remove pulley chamber cover by removing four 11 mm bolts using an 11 mm wrench.
15
CC
Figure 15: Left side of Auger axle connection
2
Remvoe left side of auger axle from Auger casing assembly by removing three bolt-washer pairs using 11mm wrench.
16
CC
Figure 16: Right side of Auger axle connection
2
Remove the right side of auger axle from the pulley chamber by removing three screw-nut pairs using an 11 mm wrench and a flat head screw driver.
17
CC
Figure 17: Auger blades to axle end connection
2
Remove the auger blades by removing eight 11 mm bolt-nuts using a ratchet.
18
CC
Figure 18: Auger brace to Auger axle connection
2
Detach the two auger braces from the auger axle and the auger blades by removing five 11 mm bolt-nuts using a ratchet.


Intent of Disassembly:

Removing the auger required more maneuvering of the snowblower and more bolts to remove than the previous steps. It was necessary to remove one of the side panels to unfasten the necessary bolts to remove the auger. Although it was probably not intended to be removed, with a little bit of work, the auger could be taken out and replaced if the owner chose to.

Step 8: Gear Chamber

Time Estimation: 15 minutes

Table 8: Gear Chamber
Sub-Step # Image Difficulty Instruction
19
CC
Figure 19: Auger pulley and belt connection
1
Detach the auger pulley and belt loop by hand.
20
CC
Figure 20: Belt guidance bracket to pulley chamber connection
1
Detach belt guidance bracket by removing one 11 mm nut-bolts using an 11 mm wrench.
21
CC
Figure 21: Pulley bracket to pulley chamber connection
2
Detach pulley and bracket by removing two 13 mm nut-bolts using a 13 mm wrench.


Intent of Disassembly:

Although it is not difficult to expose the gear chamber by removing the side panel, the contents of the chamber was not meant to be taken apart beyond perhaps replacing the belt. Even to do this requires the removal of several fasteners. This disassembly would most often be the work of a repairman rather than that of an average snowblower owner.

Step 9: Chute Base Removal

Time Estimation: 20 minutes

Table 9: Chute Base
Sub-Step # Image Difficulty Instruction
22
CC
Figure 22: Auger axle bracket to Auger scoop connection
2
Detach the auger axle bracket from between the auger scoop and the pulley chamber by removing two 11 mm bolt-nuts using an 11 mm wrench.
23
CC
Figure 23: Attached chute funnel
2
Detach the auger chute funnel from the side panels by removing two 11 mm nut-washers using an 11 mm wrench.
24
CC
Figure 24: Chute base to chute funnel connections
2
Detach the chute half-frame bases from the chute direction regulator by removing 4 bolt-washer-nut pairs using two 11 mm wrenches. Detach spring by hand.
25
Chute base connector base
Figure 25: Chute base connector base
2
Detach the chute base brace by removing two bolts using a 13mm ratchet.
26
CC
Figure 26: Scoop to chute funnel connection
2
Detach the chute funnel from the edge of the auger scoop by removing five bolt-nut pairs using two 11 mm wrenches.
27
CC
Figure 27: Scoop wedge to Scoop connection
2
Unfasten the plastic scoop wedge from the auger scoop by removing three bolt-nut pairs using a 5 mm wrench.


Intent of Disassembly:

The chute base was not intended to be disassembled. The only advantage gained by removing this piece would be additional exposure of the engine, which is required for a full dissection of the two-cycle gas engine, but not necessary for most engine repairs that might need to be made. Additional evidence that this part was not intended to be removed is the number of fasteners that had to be taken out in order for the chute base to be free to remove.

Step 10: Side Panel Removal

Time Estimation: 10 minutes

Table 10: Side Panel Removal
Sub-Step # Image Difficulty Instruction
28
CC
Figure 28: Right side panel connection
2
Detach right side panel from the main cross frame by removing 1 bolt-nut pair using a 14 mm ratchet.
29
CC
Figure 29: Middle of pulley chamber to frame connection
2
Detach the middle of the pulley chamber from the main cross frame by removing 2 bolt-nut pairs using a 13 mm wrench.
30
CC
Figure 30: Back of pulley chamber to frame connection
2
Detach the back of the pulley chamber from the main cross frame by removing 2 bolt-nut pairs using a 13 mm wrench.
31
CC
Figure 31: Driver pulley to crankshaft
2
Detach the driver pulley from the crankshaft by removing one 8 mm square bolt.


Note: The spring on the side panel was left attached. Removing the spring would risk deforming the metal which would make reassembling the side panel more difficult.

Intent of Disassembly:

The side panel was not intended to be removed. Again, there is little advantage gained by taking away this component and the difficulty of achieving this disassembly is much beyond what would be reasonable.

Step 11: Gas Tank Removal

Time Estimation: 8 minutes

Table 11: Gas Tank Removal
Sub-Step # Image Difficulty Instruction
32
CC
Figure 32: Gas tank to Frame connection
2
Detach gas tank from the main cross frame member and the pull-start bracket by
removing two bolts using an 11 mm wrench. Detach fuel hose to fuel valve by hand.


Intent of Disassembly:

Although this step is quite simple since only two fasteners need to be removed, the gas tank is contained below the red casing. For this reason, the gas tank was not intended to be removed. The gas tank was designed with an opening that protrudes through the casing to allow the user to refill the tank with fuel rather than having to remove the entire tank to perform this task. Based on its design, the gas tank was not intended to be fully removed.

Step 12: Engine Removal

Time Estimation: 20 minutes

Table 12: Engine Removal
Sub-Step # Image Difficulty Instruction
33
CC
Figure 33: Fuel Valve Pin and Spring
1
Detach the fuel valve assembly from the fuel valve connector pipe by unscrewing two Phillips head screws in the fuel valve assembly.
34
CC
Figure 34: Pull-start bracket member to cross frame connection
2
Unfasten the pull-start bracket member from the main cross-frame member by removing two bolt-nuts using an 11mm wrench. This will detach the engine block from the cross-frame.
35
CC
Figure 35: Pull-start case to engine block connection
2
Unfasten small end of the pull-start bracket member from the engine block with 2 nuts using an 11mm wrench
36
CC
Figure 36: Pull-start case to engine block connection
2
Unasten the pull-start bracket member from the engine block with 4 bolts using an 11mm wrench.
37
CC
Figure 37: Pull-start case to frame connection
2
Unfasten the pull-start bracket member from the flywheel covering by removing one 13 mm nut-washer pair using a ratchet. The engine shaft covering can be removed by hand.


Intent of Disassembly:

The two-cycle gas engine is located in the center of the snowblower, and it is not an easy task to remove. The process could be speed up if the casing was unfastened and then rotated backwards. From here, the engine could be removed without having to thoroughly disassemble the other components as was performed in this procedure. Nevertheless, it does not seem that it was intended that the owner remove the engine.

Step 13: Engine Isolation

Time estimation: 10 minutes

Table 13: Engine Isolation
Sub-Step # Image Difficulty Instruction
38
CC
Figure 38: Detach electric motor
2
Detach the electric motor from the engine block by removing two bolts using a 10 mm ratchet.
39
CC
Figure 39: Detach Muffler
2
Detach the muffler from the engine block exhaust port by removing two bolts using a 13mm ratchet.


  • Note: during this step, two washers fell out from unknown locations within the engine cavity.

Intent of Disassembly:

At this point, it seems to be a common theme that the parts were not intended to be disassembled. To perform this task requires a number of various sized wrenches, screwdrivers, and ratchets. The same type of tools are required to dissect the engine, and for this reason, it can be concluded that the engine was not intended to be dissected by the owner of the snow-blower.

Step 14: Electric Motor

Time Estimation: 4 minutes

Table 14: Electric Motor
Sub-Step # Image Difficulty Instruction
40
CC
Figure 13: Electric motor casing connection
1
Detach the cap of the electric motor by removing two long screws using a Phillips head screwdriver.

Intent of Disassembly:

Removing the electric motor was a simple step, only requiring a wrench and screwdriver. To get to the electric motor, however, would still require removing the top casing. These two steps together are fairly quick, which suggests that the manufacturer may have intended for the owner to be able to replace the electric motor.

Step 15: Engine Housing Removal

Time Estimation: 25 minutes

Table 15: Engine Housing Removal
Sub-Step # Image Difficulty Instruction
41
CC
Figure 41: Connector Pipe
1
Remove the fuel valve connector pipe from the engine block import orifice by removing two screws using a Phillips head screw driver.
42
CC
Figure 42: Engine Housing connection
2
Detach the flywheel housing from the engine block by removing six 10 mm bolts using a ratchet.
43
CC
Figure 43: Detaching Piston top
2
Detach the spark plug component from the engine block by removing four bolts using a 13 mm ratchet.
44
CC
Figure 44: Detaching Spark Plug battery
2
Detach the spark plug box from the engine block heat sink by removing two bolts using a 10 mm ratchet.
45
CC
Figure 45: Detaching Spark Plug
1
Unscrew Spark Plug from Piston Chamber top by hand
46
CC
Figure 46: Detach Fuel regulator bracket
2
Detach the fuel valve regulator bracket by removing a bolt using an 8 mm wrench.

Intent of Disassembly:

Just as was pointed out in step 13, to perform this task, a number of wrenches, screwdrivers, and ratchets are required. There are too many pieces that need to be unfastened and removed for the manufacturer to have intended the engine to be dissected.

Step 16: CrankShaft

Time Estimation: 15 minutes

Table 16: CrankShaft
Sub-Step # Image Difficulty Instruction
47
CC
Figure 47: Crankshaft-pin connection
3
Remove roller bearings on connection brace and detach from piston connector pin around crankshaft using a 4mm allen wrench
48
CC
Figure 48: Washer
1
Remove the cylindrical roller bearing and three washers from the crankshaft by hand.
49
CC
Figure 49: Connection Cup
2
Remove flywheel and cap on the crankshaft and detach with a nut using an 18 mm ratchet.
50
Bearing
Figure 50: Bearing
1
Remove the bearing and washer from the crankshaft by hand.
51
Piston
Figure 51: Piston Insertion
3
Remove the piston from the cylindrical cavity in the engine block by hand.
52
Piston
Figure 52: Piston
2
Remove the two piston rings remove the piston by hand.


Intent of Disassembly:

This part was definitely not intended to be disassembled. Upon removing the bracket member from the crankshaft, thirty-two rollers from the roller bearing fell out. These rollers will be extremely challenging to put back into place. This step also requires the use of some additional tools, such as the Allen wrench.

Step 17: Engine Shaft Covering

Time Estimation: 7 minutes

Table 17: Engine Shaft Covering Dissection
Sub-Step # Image Difficulty Instruction
53
CC
Figure 53: Pull-start to case connection
2
Detach the pull-start mechanism from the flywheel covering by removing four bolts using an 8 mm wrench.
54
CC
Figure 54: Pull start connecting brace connection
2
Detach the pull-start connecting brace from the pull-start mechanism by removing three bolts using a 5 mm wrench.


Note: At this point, all the inner components of the two-cycle gas engine can be viewed.

Intent of Disassembly:

The engine shaft covering was not intended to be disassembled. There are too many steps required that lead up to the point where you could even begin to dissect this component. And once it is taken apart, it would take just as long to put the pieces back together.

Step 18: Fuel Valve Dissection

Time Estimation: 5 minutes

Table 18: Fuel Valve Dissection
Sub-Step # Image Difficulty Instruction
55
CC
Figure 55: Fuel Valve Pin and Spring
2
Detach the spring and pin from the fuel valve.
56
CC
Figure 56: Fuel Valve Construction
1
Remove a bracket and spacer on either side of the fuel valve assembly and unscrew
two Phillips head screws which go through the holes in the brackets, spacers, and fuel valve. All this can be done by hand.
57
CC
Figure 57: Detach valve top casing
2
Unscrew the rubber gasket and cap to the fuel valve assembly by hand. Detach with 4 screws using a Phillips head screw driver.

Intent of Disassembly:

The fuel valve assembly was probably not intended to be disassembled. It was located on the outside of the engine, which makes it more accessible than the inner engine components, but the casing would still have to be removed to allow the owner access to beginning disassembly of the fuel valve. Perhaps the manufacturer believed that it would be useful to make this component accessible enough to be inspected if there was a problem, although it would still require a number of tools to carry out the procedure.

Subsystem Analysis

Subsystems

This section outlines the main subsystems which compose the makeup of the Toro Snow-blower. Outlining these systems will provide a clearer understanding of the connections which exist between them. These connections will be thoroughly explained in the section ahead.

1. Frame: The frame is comprised of the casing, which is meant to house and protect the other components, as well as the control panel, handle and wheels.

2. Pull start mechanism: The pull start mechanism includes the handle, string, and spring wound device.

3. Electric start mechanism: This includes the electric motor and the switch on the front control panel.

4. Engine: The engine includes the crankshaft, the piston, the connecting pin, and the engine housing.

5. Pulley belt system: This includes the belt and the series of pulleys necessary to relocate the rotational energy of the crankshaft to the auger.

6. Fuel System: The fuel system includes the gas tank, gas valve, and the tube connecting the two.

7. Belt engage system: This is comprised of the engage handle as well as the engage cable.

8. Auger system: Includes the auger blade as well as the axle on which it rotates.

9. Chute system: The chute and the handle used to turn it make up the chute system.

10. Exhaust system: The Muffler and its corresponding connection to the engine make up the exhaust system.

11. Primer system: Primer control and Carburetor

Connection of Subsystems

Connection 1: Pull start mechanism to the engine:

How are they connected:

  • Physically - The pull start-mechanism is connected to the frame at the side panel and is held in place using bolts. The pull-start has small metal clips that lock into the pull-start connection cup, which is attached to the crankshaft. When the chord is pulled, the clips are protracted and catch onto the connection cup.
  • Energy - Translational energy from pulling the string is converted to rotational energy by its connection to an axle housed next to the side panel. When the pull-start is activated, small metal clips lock into the pull-start connection cup, which is attached to the crankshaft. A spring in the connection of the pull-start retracts the cord after each tug.

Reason for Connection:

  • To transfer the rotational energy generated from the pull start mechanism to the crankshaft.

Connection 2: Engine to Pulley belt

How are they connected:

  • Physically - The connection between these two systems is the belt which is turned by the pulley on the end of the crankshaft, which turns the pulley connected to the Auger system.
  • Energy - Rotational energy from the the crankshaft pulley moves the belt which transfers the rotational energy to the auger pulley.
  • Signal - A human signal is required from the blade engage system to allow these two subsystems to connect.

Reason for connection:

  • To displace the rotational energy from the crankshaft to the auger.

Connection 3: Belt Engage system to Pulley belt System

How are they connected:

  • Physically - The engage cable connects the engage handle to the pulley system.
  • Energy - Human energy is translated from the user pulling the engage handle to pulley belt system.
  • Signal - The signal is provided by the operator pulling the engage handle.

Reason for connection:

  • These systems are connected to allow the user to engage the auger to rotate. When the handle is engaged the belt is pulled taut around the pulley. This causes the belt to move transferring energy to auger pulley.

Connection 4: Pulley Belt System to Auger System

How are they connected:

  • Physically - The auger axle is attached to one of the pulleys in the pulley system using three 11 mm bolts and a cylindrical ball bearing component.
  • Energy - The pulley system provides rotational energy to the auger.

Reason for connection:

  • These systems are connected to each other to provide energy to the auger allowing it to rotate.

Connection 5: Fuel System to Engine System

How are they connected:

  • Physically - There is a rubber tube which allows for the gas oil mixture to pass from the fuel system to the fuel valve. The fuel valve is attached to the engine using 2 Phillip's head screws which connect to the engine housing.
  • Mass - Fuel is transferred from the fuel tank to fuel valve, which injects the the fuel into the combustion chamber. The primer is also connected to the fuel valve, and is used to draw fuel into the valve prior to starting the engine.

Reason for connection:

  • The engine and fuel system must be connected to provide fuel for the combustion reaction which drives the engine.

Connection 6: Engine system to exhaust system

How are they connected:

  • Physically - The muffler is fastened to the engine by two 13 mm bolt-washer pairs.
  • Energy - Thermal energy may be released through some of these components.
  • Mass: Air is expelled from the combustion chamber and out of the muffler.

Reason for connection:

  • A path must be provided for air to be expelled from when it comes out of the combustion chamber.

Connection 7: Electric start system to Engine System

How are they connected:

  • Physically - The electric motor is fastened to the engine housing by two 10mm bolts. The gear assembly of the motor then connects to the teeth of the large crankshaft gear.
  • Energy - The motor transfers its electrical energy into rotational energy which is translated through the gears which turns the crankshaft.
  • Signal - An electrical signal must be provided by the user pushing the start button.

Reason for connection:

  • The electric start motor must be located adjacent to the engine in such a way that power generated from the motor can be transferred into the crankshaft to start the engine.

Connection 8: Engage Handle to Frame

How are they connected:

  • Physically - The tension of the engage handle holds it in place on the frame handle. The engage handle is secured on each side by a pin hole; it can be rotated at these pin holes to activate.
  • Energy - By activating the engage handle, I cable that is strung along the side of the handle bars is tightened. This translational motion is transferred along the cable to the clutch.
  • Signal - The purpose of the engage handle is to signal the auger to begin rotating. The translational motion of the tightening cable signals the clutch to activate and the auger to begin rotating.

Reason for connection:

  • The engage handle is connected to the frame handle because this it needs to be located in a place which allows the user to easily access it whilst pushing the snow-blower.

Connection 9: Pull Start Mechanism to Frame

How are they connected:

  • Physically - The pull start-mechanism is connected to the frame on the side of the engine housing and is held in place using four 8mm bolts and four nuts.

Reason for connection:

  • The pull start mechanism is attached to the frame to hold it in place and to protect it from damage. It is also held here so the proper connection can be made to transfer energy from the pull start to the engine. The connection between pull start and engine is discussed previously in Connection 1.

Connection 10: Fuel System to Frame

How are they connected:

  • Physically - The fuel tank is connected to the engine frame that crosses the inside of the snow-blower. It is held in place by four 11mm bolts and 4 nuts respectively.

Reason for connection:

  • The placement of the fuel system is important because it must have be accessible to the user in order for the tank to be refilled. It must be far enough away from the engine that the thermal energy given off by the combustion process does not damage or melt the container material.

Connection 11: Auger System to Frame

How are they connected:

  • Physically - The auger is connected to the frame by the auger axle, which is secured between the side panels using two ball bearings that are bolted to the panels by six 11 mm bolts and six nuts. Three bolt-nut pairs and one ball bearing connected the Auger to each side.

Reason for connection:

  • The location of the auger to the frame is crucial because provides the inlet for the snow and debris to enter the system. It must be located conveniently such that when the device is pushed forward, the auger can collect snow that is in the way. The auger spans the length of the frame to allow the maximum amount ground to be cleared for the size of the device.

Connection 12: Chute to Frame

How are they connected:

  • Physically - The chute base is attached to the frame using three 13 mm bolts and three nuts respectively.

Reason for connection:

  • The Chute must be held firmly in place over the casing frame which holds the Auger System. With this connection and positioning the incoming snow can be properly redirected out of the snow-blower to a convenient location.

Connection Implementation

Global Concerns

One global factor that was considered was the discrepancies between the English and metric measurement systems. This problem was dealt with by using metric measurements for all of the nuts and bolts because this is the more commonly accepted system. This allows for easier integration into cultures around the world without the necessity to make conversions.

Societal Concerns

One societal factor addressed in the design of the subsystems can be seen in the design of the handle for the Snow-blower. It is attached to the outer casing with four bolts that can be easily removed to decrease the overall size of the machine. This ease of removal takes into account the consumer’s need for easy storage of this machine. This emphasis on ease of storage allows for a larger number of people to use this product.

Ease of maintenance stands as another societal factor that was taken into account. This can be seen in the physical connection between the plastic outer case and the inner engine frame. There are only 2 screws connecting the plastic case to the frame at the top of the machine and can be removed to fold the casing up. This allows for easy access to the inner components for most users.

Economic Concerns

One economic consideration taken into account by the designers of the Snow-blower was the cost of production. One way in which the designers of this Snow-blower cut production costs was through conservation and proper selection of materials. For example, the handle of the snow-blower is hollow to reduce the amount of material required for that part. Also, the outer casing is made out of a plastic material which provides a less expensive way to protect and house all of the inner subsystems than using steel or another heavier material. Upon an analysis of the design of this product, one can notice that the Snow-blower is a single-stage snow-blower. This means that there is no impeller that draws the snow into the chute for ejection. The addition of an impeller would lead to an increase in the cost to manufacture each snow-blower and a reflection of that cost increase on the consumer price. The designer of this product had a great understanding of their consumer base and realized that an impeller was not needed in order to complete the task that the consumer desired for the price they wanted to pay. In accordance with the notion of consumer base identification, the quality of various parts have been reduced. This is due to the fact that Toro recognizes the application of their product and understand that it is not built for large scale snow removal. For example, one can clearly see that the wheels on the Snow-blower can be greatly improved for more comfortable use, and greater product versatility. However the smaller and lower quality wheels provide an inexpensive method to accomplish the minimum consumer need of the product. Lastly, the units for the components on the snow-blower are metric. This allows for the company to outsource the production of specific parts to lower cost, without worrying about unit confusion between company divisions.

Environmental Concerns

One environmental issue considered was the life cycle of connection components. The use of steel components such as bolts, screws, nuts, and washers ensures a longer life time and less waste due to replacing parts.

Performance Concerns

The designers of this product had to consider changes in performance when designing the connections of subsystems. One way in which they designed to account for an improved performance was the introduction of redundancy into their starting systems. This snow-blower is designed with both a pull-start mechanism and an electric start system that can be used independently of one another. If one start system fails, the other method can be used to operate the machine, providing the user with a more reliable product.

Arrangement of Subsystems

In this section, the arrangement of the subsystems will be considered. Each subsystem had to be carefully placed to effectively transfer the necessary energy and signals from one subsystem to the next and ultimately achieve the overall function of removing snow and debris and relocating it to a more convenient location. To analyze the placement, the reason for each subsystem’s location will be considered, as well as which subsystems cannot be located adjacent to each other.

Figures 58 through 60 are provided below to aid in understanding the arrangement.

Figure
Figure 58: The arrangement of outer components.
Figure
Figure 59: The Arrangement of inner components .
Figure
Figure 60: The Arrangement of the control panel.

1. Frame

The function of the frame is to house the internal components, such as the fuel system, engine, and the pulley belt system. To achieve this task, the frame must be span the size of the snow-blower, so that the other components can be attached to the frame, usually using bolts. In a way, the frame must be located adjacent to all other subsystems because they are all attached to the frame, with the exception of the exhaust system, which was attached directly to the engine.

2. Pull-start Mechanism

The pull-mechanism is located primarily on the cross frame next to the engine. This is located adjacent to the crankshaft because the pull-start axle must be able to protract its teeth and catch onto the pull-start connection cup, which is directly attached to the crankshaft. This must be the location of these two subsystems because the action of tugging the pull-start cord must lead to the rotation of the crankshaft, in order for the piston to oscillate up and down. Additionally, the pull-start chord must be extended from its location next to the crankshaft beyond the exterior housing of the snow-blower. This is so the user has easy access to the pull-cord handle, without having to remove the casing. The pull-cord handle is located on the control panel with the other user controls. This is convenient because the majority of the user interactions will be performed at this control panel.

3. Electric-start Mechanism

The electric start mechanism is located adjacent to the engine, so that it can be connected by a short cable to the combustion chamber cap. The location is important because the electric start must be able to provide an initial spark within the combustion chamber to initiate the combustion reaction. The electric start is also connected by an insulated cable to a switch located on the control panel. Similar to the pull-start cord handle, the electric-start switch is located here to allow the user convenient access to interact with the device through this panel. Clumping these user points of human interaction simplifies the signaling process. The location of the control interface itself is right below the handle bars where the user would be standing, again optimizing the convenience for the user.

4. Engine

The engine is located behind the control panel and is held in place by a cross frame member that spans the length of the snow-blower from side panel to side panel. The engine includes the crankshaft, which must be located adjacent to the pull-start axle so that the rotation of this axle can be transferred to the crankshaft through the pull-start connection cup. The engine must also be located adjacent to the electric start so that it can provide the energy to the spark plug in the combustion chamber. The crankshaft has to have a connection to the pulley-belt system, which is housed in the gear chamber within the side panel. The engine also needs to be connected to the fuel system by the fuel valve, which provides the gasoline to carry out the combustion reaction. However, the fuel tank cannot be located directly adjacent to the engine due to the heat given off by the engine. This could potentially damage the plastic fuel tank.

5. Pulley-belt System

The pulley-belt system is located on the left side panel when being viewed from where the user would stand. This placement is important so that the rotational energy can be captured from a connection with the crankshaft. The pulley-system’s location on the side panel allows for the displacement of the rotational energy from the crankshaft to the auger. In this way, the pulley-belt system is also located adjacent to the auger, but it is to the side and out of the way of the rotation of the auger to protect it from damage.

6. Fuel System

The fuel system is comprised of the fuel valve and the fuel tank, along with a tube that connects the two. The fuel valve must be placed adjacent to the combustion chamber so that the fuel can be injected for use in the engine. The tube allows the fuel tank to be located further from the engine to allow the air to act as an insulator against the thermal energy emitted by the engine. The fuel tank is also located towards the surface of the main casing so that the inlet can protrude through this casing and allow the user a quick access to the fuel tank cap which can be unscrewed without requiring the use of any tools.

7. Belt Engage System

The belt engage system consists of the engage handle and the attached engage cable. The engage handle is located near the top of the handle bars. This is so the user can conveniently hold the engage handle down to begin auger rotation. The engage handle is set so that the auger will not rotate unless this handle is held down. This is for safety reasons; the auger will only rotate when the user is positioned at the handlebars and ideally is paying close attention to what is in front of the snow-blower. The engage cable is connected to the engage handle and is threaded along the side of the handle bar and is fed through a screw with a circular hook as the head. This placement of the engage chord allows for an external path to the pulley-belt system without hanging in the way of the user. The belt engage system is connected to the pulley-belt system by a spring. When the engage handle is activated, the cable becomes taut and applies tension to the spring, which activates the auger rotation by shifting the the pulley so that the auger axle is connected to the belt.

8. Auger System

The auger is located on the opposite of where the user would stand and is open to allow snow and debris to enter when the user pushes the device forward. The auger must be connected to the pulley-belt system to receive the rotational energy being transferred from the crankshaft. Additionally, the auger must be located adjacent to the chute so that the snow can be collected and directed out the chute. Since the auger is a relatively heavy rotating component with a large amount of inertia, the device needs to be separated from the other components so that no damage results from unintentional impacts. To help separate the auger, a protective plastic flap is implemented. This flap also helps to direct the snow and debris into the chute.

9. Chute System

The chute system is located directly above the auger to allow the snow and debris collected by the auger to be funneled out through the chute. The chute is located on the top of the device outside of the main casing, which allows the user to control the direction that the snow and debris is expelled. The chute must provide a path through the main casing so that the snow and debris can pass from within the auger cavity to the outside environment.

10. Exhaust System

The exhaust system is connected to the engine so that the exhaust air from the combustion reaction can be expelled into the engine cavity beneath the main casing.

11. Primer System

The function of the primer system is to provide a small amount of fuel to the carburetor, which is located directly adjacent to the combustion chamber of the engine. The primer bulb is located on the control panel interface and is meant to be pressed by the user three or four times before starting the the engine via the pull-start or electric start mechanisms. The primer system connects the control panel to the combustion chamber of the engine, allowing the human signal to prepare the engine to begin.

Functional Diagram

In this section, a functional model for the Toro CCR 2400 E GTS was created.  The first task is to determine the main job that the product performs: relocating snow to more convenient locations.  To identify the inputs and outputs of the overall function, power sources will be considered, as well as the human interaction with the device, illustrated in Figure 61.  Next, the main function will be split into first level sub-functions that consider the major subsystems and their role in the overall function, shown in Figure 62.  Second level sub-functions will then be outlined by breaking down each of the first sub-functions separately.  Particular attention will be paid to material, signal, and energy flow through the snow-blower system.  See Figure 63 for the second level sub-function diagram.


Figure
Figure 61: Shows the Overall Product functions and inputs.
Figure
Figure 62: First Level of sub-functions and their inputs and outputs.
Figure
Figure 63: Second level of functions and their flows.
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