Group 6 - Toro CCR 2400 E GTS Snow-blower - Gate 4: Product Explanation

Introduction

Following our component analysis we have taken on the task of reassembling our product. This gate contains the reassembly process in a detailed manner containing images and instructions. We have tabulated these steps and discussed how each one differed from, or stayed the same as, the method used by the manufacturer. Also, three design revisions have been proposed at a system level that discuss their respective advantages, disadvantages, and relation to the four engineering factors. This gate provides information that sets the foundation for the final conclusions to be drawn in gate 5.

Project Assessment

Throughout the completion of Gate 4 challenges have been encountered by the group and were successfully resolved:

Random parts encountered during dissection need to be reassembled

• Since the location of these random bolts, washers, and nuts could not be determined, we decided to find places for these parts as vacant spots presented themselves during reassembly.

Split of work between re-design presentation and gate

• Tyler Salamone accepted the responsibility of giving the presentation while the entire team helped compose the slides. After the slides were created, Chris O’Connell, Andy Lyons, and Joe Groele continued to work on the Gate 4 Assignment while Tyler Salamone rehearsed the re-design presentation.

Scheduling work time

• Throughout the completion of this Gate Assignment, many instances occurred where multiple group members could not attend a lab session or a group meeting due to other work requirements. In order to resolve this issue, we assigned different design revisions and sections of the Gate to each other for completion by a specific deadline. This allowed the group to stay on track with its work so that the last night before it was due was not filled with work.

Limited lab time

• Since we have such a heavy, cumbersome product for our project, we had to perform our dissection in the lab at Furnas Hall. Unfortunately, none of the group members could attend the lab session of the final day available for work due to other classes. We decided to bring the Snow-blower back to our dorms so that reassembly could continue over the weekend. This gave us ample time to complete our reassembly and keep the product close if it ever needed to be referenced.

Unresolved Challenges

• All the challenges encountered were resolved during this Gate assignment.

Product Reassembly

Reassembly Difficulty Scale

1 - A difficulty rating of 1 infers a task that requires a minimal amount of work to perform. The part being assembled requires little to no use of tools and the action is completely within the ability of the group member. For example, during reassembly, the spark plug was screwed into the top of the piston casing by hand. This action required little force to tightly secure the part and took a minimal amount of time.

2 - A difficulty rating of 2 describes a task that involves the use of basic tools such as screwdrivers and wrenches. Also, some force is required to attach the part but not at a level that the group member has to overexert himself. The task takes longer to complete but still can be done in a short amount of time. An example of a task during reassembly that deserves a difficulty rating of 2 is the attachment of bolts with respective nuts to the outer red casing. This required a group member to hold the nut in place while turning the bolt with a ratchet to fasten the part.

3 - A difficulty rating of 3 represents a task that requires a considerable amount of force to perform using basic tooling such as screwdrivers and wrenches. Also, the part’s orientation is an important factor as it needs to be correctly lined up (due to its geometry or interference from other parts) in order for it to be fastened. It takes a longer amount of time than a 2 rating and may involve multiple group members to complete. One example of this during reassembly is the placement of the piston into the engine block. The piston rings had to remain oriented so that they did not make contact with the wall of the engine block. This was to be done while the piston was pushed into the slot and required multiple group members to push in the piston and keep the rings pressed in.

Reassembly Process

During the reassembly process, the order of the steps was modified in order alleviate problems that resulted from part interference. The actual procedures that were required to fasten or unfasten the components remained the same. The reassembly process is listed in Table 1.

Table 1: Reassembly Process

Step #	Image	Difficulty	Instruction	Original Assembly	Disassembly Comparison
1	Figure 1: Piston	2	Insert the two piston rings into the piston by hand.	The step probably used a more specialized process.	Same
2	Figure 2: Piston Insertion	3	Insert the piston into the cylindrical cavity in the engine block by hand.	This step probably used a more specialized process.	Same
3	Figure 3: Bearing	1	Place the bearing and washer onto the crankshaft by hand.	Same	Same
4	Figure 4: Connection Cup	2	Place flywheel and cap on the crankshaft and attach using an 18 mm nut and fasten using an 18 mm ratchet.	Same	Same
5	Figure 5: Washer	1	Place the cylindrical roller bearing and three washers onto the crankshaft by hand.	Same	Same
6	Figure 6: Crankshaft-pin connection	3	Place roller bearings on connection brace and attach to piston connector pin around crankshaft using ( size ) allen wrench	This step probably used a more specialized process.	Same
7	Figure 7: Engine Housing connection	2	Fasten the flywheel housing to the engine block with six 10 mm bolts using a ratchet.	Same	Same
8	Figure 8: Attaching Spark Plug	1	Screw Spark Plug into Piston Chamber top by hand	Same	Same
9	Figure 9: Attaching Piston top	2	Fasten the spark plug component to the engine block with four 13 mm bolts using a ratchet.	Same	Same
10	Figure 10: Attaching Spark Plug battery	2	Fasten the spark plug box to the engine block heat sink using two 10 mm bolts using a ratchet.	Same	Same
11	Figure 11: Attach Connector Pipe	1	Fasten the fuel valve connector pipe to the engine block import orifice using two Phillips head screws.	Same	Same
12	Figure 12: Electric motor casing connection	1	Attach the cap of the electric motor using two long Phillips head screws.	Same	Same
13	Figure 13: Attach electric motor	2	Fasten the electric motor to the engine block with two 10 mm bolts using a ratchet.	Same	Same
14	Figure 14: Attach Muffler	2	Attach the muffler to the engine block exhaust port with two 13 mm bolts using a ratchet.	Same	Same
15	Figure 15: Attach Fly Wheel Gear	1	Snap the flywheel gear in place on the flywheel by hand.	Originally 3 bolts were used to attach this component.	Same
16	Figure 16: Attach Fuel regulator bracket	2	Fasten the fuel valve regulator bracket with an 8 mm bolt using an 8 mm wrench.	Same	Same
17	Figure 17: Attach valve top casing	2	Secure the rubber gasket and cap to the fuel valve assembly by hand. Attach with 4 screws using a Phillips head screw driver.	Same	Same
18	Figure 18: Fuel Valve Construction	1	Place a bracket and spacer on either side of the fuel valve assembly and insert two Phillips head screws into the holes in the brackets, spacers, and fuel valve. All this can be done by hand.	Same	Same
19	Figure 19: Fuel Valve Pin and Spring	2	Attach the spring and pin from the fuel valve to the fuel valve regulator bracket.	Same	Same
20	Figure 20: Fuel Valve Pin and Spring	1	Fasten the fuel valve assembly to the fuel valve connector pipe using two Phillips head screws that are already in place on the fuel valve assembly.	Same	Same
21	Figure 21: Pull start connecting brace connection	2	Fasten the pull-start connecting brace to the pull-start mechanism with three 5 mm bolts using a wrench.	Same	Same
22	Figure 22: Pull-start to case connection	2	Fasten the pull-start mechanism to the flywheel covering with four bolts using an 8 mm wrench.	Same	Same
23	Figure 23: Pull-start case to frame connection	2	Fasten the pull-start bracket member to the flywheel covering with one 13 mm nut-washer pair using a ratchet.	Same	Same
24	Figure 24: Pull-start case to engine block connection	2	Fasten the pull-start bracket member to the engine block with 4 bolts using an 11mm wrench.	Same	Same
25	Figure 25: Pull-start case to engine block connection	2	Fasten small end of the pull-start bracket member to the engine block with 2 nuts using an 11mm wrench	Same	Same
26	Figure 26: Engine block to cross frame connection	1	Fasten the engine block to the main cross-frame member with four 13 mm bolt-washer pairs using a ratchet.	Same	Same
27	Figure 27: Pull-start bracket member to cross frame connection	2	Fasten the pull-start bracket member to the main cross-frame member using two 11 mm bolt-nuts. This will secure the engine block to the cross-frame.	Same	Same
Status check	Figure 28: Assembly status	N/A	This is what the assembly should look like at this point.	N/A	N/A
28	Figure 29: Pulley bracket to pulley chamber connection	2	Attach pulley and bracket with two 13 mm nut-bolts using a 13 mm wrench.	Same	Same
29	Figure 30: Belt guidance bracket to pulley chamber connection	1	Attach belt guidance bracket with one 11 mm nut-bolts using an 11 mm wrench.	Same	Same
30	Figure 31: Driver pulley to crankshaft	2	Attach the driver pulley to the crankshaft using one 8 mm square bolt. This will loosely connect the pulley chamber to the main cross frame member.	Same	Same
31	Figure 32: Back of pulley chamber to frame connection	2	Secure the back of the pulley chamber to the main cross frame with 2 bolt-nut pairs using a 13 mm wrench.	Same	Same
32	Figure 33: Middle of pulley chamber to frame connection	2	Secure the middle of the pulley chamber to the main cross frame with 2 bolt-nut pairs using a 13 mm wrench.	Same	Same
33	Figure 34: Gas tank to Frame connection	2	Attach gas tank between the main cross frame member and the pull-start bracket with two 11 mm bolts using an 11 mm wrench. Attach fuel hose to fuel valve by hand.	Same	Same
34	Figure 35: Right side panel connection	2	Attach right side panel to the main cross frame with 1 bolt-nut pair using a 14 mm ratchet.	Same	Same
35	Figure 36: Scoop wedge to Scoop connection	2	Fasten the plastic scoop wedge to the auger scoop with three bolt-nut pairs using a 5 mm wrench.	Same	Same
36	Figure 37: Scoop to chute funnel connection	2	Attach the chute funnel to the edge of the auger scoop with five bolt-nut pairs using two 11 mm wrenches.	Same	Same
37	Figure 38: Chute base connector base	2	Attach the chute base brace with two bolts using a 13mm ratchet.	Same	Same
38	Figure 39: Chute base to chute funnel connections	2	Attach the chute half-frame bases on the chute direction regulator with 4 bolt-washer-nut pairs using two 11 mm wrenches. Attach spring by hand.	Same	Same
39	Figure 40: Auger brace to Auger axle connection	2	Attach the two auger braces to the auger axle and the auger blades using five 11 mm bolt-nuts using a ratchet.	Same	Same
40	Figure 41: Auger blades to axle end connection	2	Attach the auger blades with eight 11 mm bolt-nuts using a ratchet.	Same	Same
41	Figure 42: Attached chute funnel	2	Attach the auger chute funnel to the side panels with two 11 mm nut-washers using an 11 mm wrench.	Same	Same
42	Figure 43: Auger axle bracket to Auger scoop connection	2	Attach the auger axle bracket between the auger scoop and the pulley chamber using two 11 mm bolt-nuts using an 11 mm wrench.	Same	Same
43	Figure 44: Left side of Auger axle connection	2	Attach left side of auger axle to Auger casing assembly with three bolt-washer pairs using 11mm wrench.	Same	Same
44	Figure 45: Right side of Auger axle connection	2	Attach the right side of auger axle to the pulley chamber with three screw-nut pairs using an 11 mm wrench and a flat head screw driver.	Same	Same
45	Figure 46: Auger pulley and belt connection	1	Attach the auger pulley and belt loop by hand.	Same	Same
46	Figure 47: Fastening pulley chamber	2	Fasten pulley chamber cover in place with four 11 mm bolts using an 11 mm wrench.	Same	Same
47	Figure 48: Attaching case brackets to top red casing	2	Attach plastic and metal case bracket to top red casing with 8 nuts by wrench	Same	Same
48	Figure 49: Black ventilation casing attachment	2	Attach black ventilation casing to top red casing using 3 bolt-nut-washer pairs	Same	Same
49	Figure 50: Connecting top casing, control panel, and back casing	2	Attach top and back red casings and control panel using 2 bolts with a 8mm ratchet	Same	Same
50	Figure 51: Attach casing assembly to body	2	Attach the casing-control panel assembly to the body using 2 Phillips head screw-washer-nut pairs and 2 bolts with a 12 mm wrench	Same	Same
51	Figure 52: Attach bottom casing to body	2	Turn assembly on its side and attach bottom plastic flap using 2 nuts and adjustable wrench	Same	Same
52	Figure 53: Attach gas cap	1	Turn assembly upright, screw gas cap on by hand	Same	Same
53	Figure 54: Attach Chute shaft and handle	2	Attach chute shaft and chute handle to chute base with 3 bolts using adjustable wrench	Same	Same
54	Figure 55: Attach Chute top to chute shaft	2	Attach chute top to chute shaft with 2 bolt-nut-washer pairs using adjustable wrench	Same	Same
55	Figure 56: Wheel	1	Attach wheels by hand ( missing end nuts)	Originally connected by some sort of fastener.	Same
56	Figure 57: Attach bottom of lower handle to frame	2	Attach bottom of lower handle to frame using 2 bolt-washer pairs	Same	Same
57	Figure 58: Attach middle of lower handle to frame	3	Attach middle of lower handle to frame with 2 bolt-bearing-washer-nut pairs	Same	Same
58	Figure 59: Attach lower handle to upper handle	2	Attach lower handle to upper handle using 3 bolt-nut pairs and 1 eye-hook and nut pair	Same	Same
59	Figure 60: Attach engage handle to upper handle	1	Attach engage handle to upper handle by hand	Same	Same
60	Figure 61: Attach engage cord to pulley chamber bracket and engage handle	1	Attach engage cord from pulley brace to engage handle	Same	Same
61	Figure 62: Attach engage spring to bracket and frame	3	Attach spring from frame to pulley brace (Step should be done earlier for easier assembly)	This spring was attached earlier in the process.	Same
Status: complete	Figure 63: Reassembled Snow-blower	N/A	The Snow-blower is now completely reassembled.	N/A	N/A

Design Revisions

This section will recommend three design changes for the product at the system level. These revisions will address global, societal, economic, or environmental concerns as they apply to they apply the snow-blower. While there are many significant changes that could be made to improve performance and ease of use, the products’ target audience will be considered when presenting these design revisions. This particular snow-blower model was designed to be an affordable alternative to the more expensive two-stage snow-blowers that are available. The proposed design revisions improve the product without driving the price into the range of two-stage snow-blowers, thereby maintaining the target audience and price point.

The first design revision is raising the control panel closer to the user to help consolidate the user interaction.

Raise Control Panel Closer to User

Figure 64: Example of a raised control Panel

One design revision proposed by the group is to raise the control panel from the base of the handle bars to where the operator grasps the handlebars. Currently, the control panel resides between the top and lower red casings and is very low to the ground compared to the user. The operator must bend down to an uncomfortable angle in order to perform the operations available on the panel including the primer, ignition key, pull-start cord, and electric start button. This introduces safety hazards for the operator in that if the engine needs to be turned off for any reason during operation, the user has to bring himself closer to the moving parts of the Snow-blower in order to turn the key.

By raising the location of this control panel, the user has the vital operations of the Snow-blower closer to him improving the Snow-blower’s safety and ease-of-use. In terms of improving safety, the operator now is farther away from the rotating auger, running engine, and snow chute if a problem occurs and the machine needs to be turned off. The Snow-blower’s ease of use would increase in a similar manner due to its close proximity to the user’s hands. The control panel would rest in between where the operator places his hands to push the Snow-blower (A design often used in 2-stage Snow-blowers). As a result, the operator now can access the main functions of the Snow-blower without difficulty.

In order to implement this design revision, the top handle bars need to be redesigned in order to accommodate the control panel. The operator will hold onto extended short bars covered in a soft, synthetic material for comfort. These bars will protrude out horizontally from the top bar providing a large space in between for the control panel to sit. The panel would then be fastened with bolts in this created gap and angled for an ergonomic viewing experience.

Although the redesign offers improvements in a few areas, there are disadvantages that require design modifications to overcome. The functions on the control panel need to be connected to the machine in order for the Snow-blower to work. Currently, this is not a problem since the panel sits directly on the machine and does not require complex connections for its functions. However, once the control panel is raised to top of the handle bar, a new design will be needed to direct wires for the electric start, the cable for the pull-start mechanism, and the tube for the primer to the engine. This involves a complex design that effects the aesthetics of the product since consumers do not want to see exposed wires running down the machine. Also, the increased cost to the consumer exists as another challenge created by this redesign option. Since further designs and additional parts are needed to raise the control panel, the costs to the manufacturer will increase, thereby increasing the price of the Snow-blower.

Adjustable Telescoping Handle

Figure 65: Telescoping Handle Conceptual Model

The Toro CCR 2400 E GTS snow-blower is a simple single-stage snow-blower. It was designed to be an affordable alternative to the more powerful but higher priced two-stage snow-blower options. The result of this lower cost is a smaller, more portable, and easier to store snow removal device when compared to the two-stage models. Many people, especially those that live in urban environments would find this cheaper single-stage snow-blower to perform sufficiently for the low volume snow removal required, and the maneuverability and storage capability offered by its smaller volume is also a benefit. The purpose for this model of Toro snow-blower leads to design considerations based on making this product convenient to use for as wide of a user base as possible, without significantly increasing the cost. One redesign option that would further accomplish this goal is the development of a reconfigurable handle bar.

The proposed adjustable handle bar would be capable of being adjusted to varying heights or shorted to the lowest setting for more compact storage geometry. This can be considered a societal design consideration because it makes storage easier to accommodate, a particular advantage for owners who live in urban regions where storage space can be limited. The adjustable handle bar would allow the device to be used comfortably by a wider user base of variable dimensionalities, an advantage for particularly tall users who might be required to lean over in order to operate the snow-blower. People who own the current model that are in this situation who are happy with the product otherwise would likely consider purchasing the redesign snow-blower with the reconfigurable handle bar system just so they could operate the device more comfortably. This is also an economic design consideration for Toro. By expanding the user base for the product, Toro should be able to sell more of the redesigned snow-blower model, which would result in more profits. The disadvantage associated with this design revision is the cost increase that would result from the additional parts and the additional manufacturing processes required to achieve proposed redesign.

There is still further research and information required to ensure the successful redesign of Toro snow-blower. Information on the extension range of the handle bar should be gathered. Toro would want to know what the upper and lower bounds that the handle bar can be adjusted to. To do this, average heights of populations should be considered, along with the standard deviations; conclusions should be drawn on how much percent of the varying height populations can be efficiently accommodated. And ergonomics study should be performed to determine what handle bar heights are comfortable for what range of user heights. Further analysis needs to be taken to determine the effect of the design revision on the cost of manufacturing and the retail price. Also, how will this effect profit predictions? A study should be performed to help answer these questions.

The construction of economic and functionality models would also aid in the design revision process. Both of these categories would take the form of mathematical models, in which equations are used to provide quantitative predictions. The economic model would be generated to weigh the costs of the design revision against the profits that could be gained by the expanded user base. One functionality model could be a mathematical model used to predict the amount of storage space that could be saved by placing the adjustable handle bars in the lowered mode. Another functionality model could be focused on providing a quantitative estimate of the percent of the population’s height range that is now accommodated by the reconfigurable handles.

In order to complete this design revision, technology would need to be researched to develop an adjustable engage cable mechanism. Since the engage cable is connected to the engage handle on the handlebars, the movement of the handlebars would affect the tension in the engage cable, causing this mechanism to fail. One technology that could be used to solve this issue is a remote signal that is battery powered and located on the handle bar for easy access. There would no longer be a physical connection from the engine to the handle bars. Instead, auger rotation can be activated by an electromagnetic signal. This modification would be cheap enough not to significantly raise the price range of the product, allowing it to maintain its market niche as compact and affordable snow-blower model.

Chute Adjustment Mechanism

Figure 66: Chute Adjustment Mechanism example

Our next redesign consideration was a repositioning of the chute adjustment lever. The current arrangement has the chute adjustment handle located on the frame of the snow-blower. This makes it difficult to reach while operating. We propose to move it higher up towards the user on the handle bars so that they can more easily access and utilize it while operating the snow-blower. We propose to have a crank handle which rotates the chute when cranked by the user.

This design revision stems from a combination of societal factors. Firstly, it will improve ease of use. Having the adjustment crank closer to the user allows them to more easily change the direction of the chute. This revision is also a result of a desire to improve safety. Having the crank handle located higher up the handle of the snow-blower will mean that it is further away from moving parts, reducing the risk of injury.

As with any modification, this revision does have some negative consequences. One such disadvantage is an increase in cost. The additional parts and increased complexity will result in higher material and production costs. This cost would be passed onto the consumer in the form of a rise in price of the snow-blower.