OHIO University Mechanical Engineering Conceptual … rollers subsystem included rollers in Figure...

OHIO University Mechanical Engineering Conceptual Design Report

GOOD EARTH BEAN SHELLER

Team Green Bean

Chris Allen

Mark Hritz

Andrew Janosik

Dan Knuckles

Sean Mefferd

Michael Seiser

1/13/2012

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1.0 Concept Generation

1.1 Problem Statement for Concept Generation

Due to the gap between small gardens and large commercial farms, there is a need for automated

mechanical systems to perform time consuming tasks on medium scale farms. Farms of this size

include those run by independent farmers or not-for-profit farms that operate on a volunteer

basis. In particular, there is a need for a machine that will accept a variety of bean pods as input

and produce shelled beans as output, with little to no work required by the operator.

The first step in concept generation was to identify the methods currently employed to

accomplish this task. The black box model was then used as a basis for each member of the team

to generate various complete system concepts. Upon identifying successful methods to remove

beans from pods, the black box was designated as a complete system that takes bean pods in and

outputs shelled beans. Each member of the team is required to define their complete system

including all subsystems. Circular brainstorming was then employed to identify the strengths,

weaknesses, and possible opportunities for improvement of each concept.

1.2 Patent Search

The patent search performed by the group resulted in a large variety of concepts that have been

previously designed. The patented concepts varied in scale and method. The patents also varied

in age, with some dating back to the mid 1800’s. The patents were sorted by method of operation

and several of the most relevant patents to our concept design are shown below.

1.2.1 Roller Method Patents

The first group of patents shown use the “roller method” for de-shellling beans. In general,

patents for this method were the oldest. Also, these patented concepts are for a small scale

operation. Figure 1.1 shows a patented roller method “pea sheller.”

[The rest of this page intentionally left blank]

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Figure 1.1: Roller Method [1]

The concept shown above is from 1864. It uses a hand crank to drive the main two rollers as

well as a conveyor feed system. The conveyor is driven by a pulley system. The gap between

the two rollers can be easily adjusted with a screw mechanism at the top of the machine. The

beans are separated from their pods after they move through the rollers. This method of

separation is different from most of the other roller method designs. The most typical method of

separation is to have the peas stay on the feed side of the rollers while the pods move to the other

side. An additional patent is shown below in Figures 1.2 and Figure 1.3.

Figure 1.2: Double Roller Mechanism [2]

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In Figure 1.2 and Figure 1.3, two sets of rollers are used to de-shell the beans. When the beans

go through the first set of rollers, they are sliced open by the bottom roller. The top roller has

ridges on it to help pull the beans through. This process is shown in Figure 1.2. The next set of

rollers are placed close together so that the pods get pulled through but the beans are left behind

as shown in Figure 1.2.

Figure 1.3: “Pre-slicing” method [2]

Another common design of roller systems is to have some type of gripping features on the

rollers. One patent that incorporates this design is shown in Figure 1.4.

Figure 1.4: Sheller with Studded Rollers [3]

This patent is for a small scale sheller, and has two very small studded rollers.

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1.2.2 “Tumbler” Method Patents

The next group of patents shown is for “tumbler” style shelling mechanisms. These types of

machines consist of spinning arms inside of a cylinder that break the beans out of their pods.

Tumbler style machines can typically handle a much higher load capacity than that of the roller

method machines. A simple design for a tumbler method machine is shown below in Figures 1.5

and Figure 1.6.

Figure 1.5: Tumbler Front View [4]

Figure 1.6: Tumbler Side View [4]

This machine, as well as most tumbler method machines, uses a screen with properly sized holes

for shelled beans to fall through which leaves the pod remnants inside the chamber. After all the

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beans are shelled, the pods are then removed from the device and a new batch of beans can be

loaded for the next run. Tumbler method machines can become increasingly complex and

efficient. Figure 1.7 shows a more complicated design.

Figure 1.7: Advanced Tumbler Machine [5]

This machine operates on the same basic principles as the previously shown mechanism but has

several additional features. First, this machine includes a two piece, slide-able screen to easily

adjust hole sizes. Instead of the shelled beans falling straight into a bin after falling through the

screen, the beans fall onto a conveyor. The conveyor moves the beans to an air blower

contraption that further sorts the beans from any small, unwanted debris that may have fallen

through the screen. The lighter debris are then blown up and captured in a separate container.

This process is shown in Figure 1.8.


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Figure 1.8: Blower Mechanism [5]

Another patented design, shown in Figure 1.9, includes several different features of another

complex tumbler machine.

Figure 1.9: Alternative Tumbler Design [6]

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The first unique feature in this design is that the cylindrical drum turns as rows of beaters turn.

The patent calls out a beaters to drum rotational speed ratio of 5:1. The drum spins in the

opposite direction as the beaters. Another different feature of this design is that the beaters have

free spinning forks at the ends. The patent calls out several different types of interchangeable

tips that can be used at the ends of the beaters for different applications. This design also

includes a method for further sorting beans from hull debris after the screen of the main drum.

The design uses offset shafts on pulleys, to make two sets of screens vibrate. The vibration

motion moves the beans over the screens and sorts them accordingly into collection buckets.

1.2.3 “Shearing” Method Patents

The next method of patents is for the “shearing” method. This method of shelling beans is not as

prominent as the roller or tumbler methods. Only one patent was found for a machine of this

type. The design is show in Figure 1.10.

Figure 1.10: Shearing Mechanism [7]

This device uses a hopper to feed the beans down. Once at the bottom of the hopper, the beans

are grabbed by teeth from a spinning disc. The beans are then dragged across a stationary set of

teeth and are torn open. As the beans are freed from their pods, they fall down out of the

mechanism. The ground up pods also fall into the same area.

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Initial concept generation started with each individual researching existing machines and

methods for shelling beans. This yielded two basic methods for shelling and separating beans.

The first method found was what will be called the “roller method” in which the beans are forced

through two rollers which squeezes the beans out of their pods almost like a toothpaste tube. The

second method that was found will be called the “tumbler method” in which beans are placed in

a rotating drum with a spinning shaft featuring fingers in the middle that will hit the pods and

cause them to break open. Once these three methods were bench marked, a variation of the 5-3-

5 brainstorming method was used to generate variations on what is already being deployed in the

industry. This process yielded new ideas and variations on the two methods.

To further develop new ideas and variations, each team member was asked to come up with as

many full systems as they could for each removal method. This was a key step in allowing the

team to have a very interactive and successful brainstorming session. In the team brainstorm all

of the complete systems were analyzed and broken down into subsystems where appropriate.

This break down into subsystems allowed the team to look at a system as a whole and with

interchangeable subsystems which generated many new ideas, combinations, and variations.

When deciding how to power the machine, it was determined that the two most feasible methods

were human powered and electric. Either method would utilize a single belt driven system to

turn the moving parts of the machine. An electric motor was chosen for two reasons. The first

reason to use an electric motor is because our goal for the amount of people required to run the

machines would ideally be one person. If this singular person has to pedal a bike, he or she is no

longer able to do other processes which would be required during operation. The second reason

is the speeds required for operation would require a complex gearbox system which would

complicate the design unnecessarily.


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1.3.1 Roller Method

The roller method was broken down into three subsystems; loading, orientation, and rollers. The

loading subsystems included a top load system shown in Figure 11(a), a conveyor loading

system in Figure 11(b), and hopper loading system in Figure 11(c).

Figure 11: Roller method loading variations

The top loading system in Figure 11(a) entails placing a handful of beans on the top of the

machine and feeding them in by hand. The conveyor system in Figure 11(b) consists of the

machine being fed by an operator placing a load of beans in a container at floor level in which a

conveyor would transport the beans to the top at a controlled rate. The hopper system in Figure

11(c) consists of an operator putting a load of beans into a hopper that would then feed the

machine at a rate controlled by the speed of the auger.

The orientation subsystem is a way to orient the bean pods perpendicular to the rollers so they

can pass through the rollers in the correct position. The orientation subsystem for the roller

method included an angled system with fins in Figure 12(a), an angled system with corrugation

in Figure 12(b), a flat system with fins and a conveyor in Figure 12(c), and an angled system

with fins and rollers in Figure 12(d).

Figure 12: Roller method orientation variations

All of the systems in Figure 12(a-d) are all different methods designed to orient the beans in a

perpendicular manner to the rollers.

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The rollers subsystem is the part of the machine that actually takes the full pods and separates the

beans from hull. The rollers subsystem included rollers in Figure 13(a), rollers with pre-rollers

in Figure 13(b), rollers with pre-rollers blades in Figure 13(c), and angled rollers in Figure

13(d).

Figure 13: Roller system variations

The roller system in Figure 13(a) consist of two rollers the are spaced closely enough together to

allow only the hull of the bean through the back side and force the beans out of the pod on the

front side. The rollers with pre-rollers in Figure 13(b) implement the same method but use

smaller rollers in front of the main rollers to help with feeding and bean separation. The rollers

with pre-roller blades in Figure 13(c) implement the same method as the pre-rollers but also cut

the pods as they pass through the rollers. The angled rollers in Figure 13(d) are fed vertically

instead of horizontally and have the beans roll down the angled rollers after separation.


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1.3.2 Tumbler Method

Unlike the roller method the tumbler method was not broken down into interchangeable

subsystems but three separate complete systems were generated. The three systems developed

were the single load system shown in Figure 14(a), the continuous load system shown in Figure

14(b), and the contained system shown in Figure 14(c).

Figure 14: Tumbler method variations

With the single load system shown in Figure 14(a) the full bean pods are placed inside the inner

cylinder of the machine. As the machine runs the bean pods are broken up by the rotating fingers

and are separated through the wire mesh that composes the inner cylinder. The spent pods are

left inside the cylinder while the usable beans come out through the wire mesh. After the cycle

is over the bottom tray with the beans is removed. Once the beans have been emptied out of the

tray it can be reinserted then by opening the door on the cylinder the empty pods then be emptied

into the tray to be removed. The continuous load system in Figure 14(b) uses a mesh cylinder

like the single load system but instead of containing the pods inside the cylinder the pods slowly

work their way through a much longer cylinder and exit at the end. The contained system in

Figure 14(c) does not have any separation system, so it must have an additional sub-system to

accomplish the task of separating the beans from the hulls.


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2.0 Concept Screening and Evaluation

2.1 Concept Screening

The team’s concept generation determined several subsystems to accomplish the tasks of

loading, orienting, bean removal, and pod separation. The roller method requires a subsystem

that orients the beans perpendicular to the rollers for proper removal, while the tumbler method

requires no orientation. Also, the tumbler method requires a subsystem that will separate the

shelled beans from the empty pods, while the roller method separates the pod from the bean

when it is removed. Due to the difference in removal method between the tumbler and the

rollers, it was necessary to evaluate the subsystems for loading, orienting, and separating

individually. Each subsystem was then put into a matrix and compared to other variations based

on the following:

● ease of use - how easy it is for the operator to use the machine

● load handling - how well the machine can handle a large load without jamming or failing

● manufacturability - how difficult it will be for the team to manufacture

● versatility - the capability to shell different types of beans

● simplicity - how simple the overall design is

● rate - how fast the machine can remove the beans and separate the empty pods

● certainty of success - the team’s overall certainty that the machine will function properly

Each variation was scored on a 1-5 scale with 1 being the lowest, 3 being neutral, and 5 being the

highest.

2.1.1 Roller Method

The roller method compared the variations in each of the loading, orienting, and roller

subsystems to each other based on the previously stated criterion. Table 2.1 shows the matrix

used to compare the different loading subsystems of the roller method, while Tables 2.2 and 2.3

present the orientation and roller subsystems.


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Table 2.1: Loading concept variants for the roller method

Table 2.2: Orienting concept variants for roller method

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Table 2.3: Rollers concept variants for the roller method

Upon completion of the roller method subsystem analysis, the team was able to determine which

concepts would be further analyzed in the final design selection matrix. For the loading

concepts, the team decided to use the hopper concept and omit the other two ideas. Since one of

the goals of this project is to improve on an existing design, the hopper is best because it

automates the feeding process. Without it, loading is limited to feeding by hand. For the

orienting concepts, fins and corrugation concepts were kept through the final selection analysis.

The conveyor and roller concepts were eliminated due to the difficulty in manufacturing them,

along with a lack of certainty in their success. To manufacture an orienting system with rollers

would incorporate more parts to manufacture, and could potentially lead to jamming during

operation. The conveyor system is a rather complex system that is particularly prone to tracking

of the conveyor belt. Upon deciding to continue with fins and corrugation, cardboard mock-ups

were created to test their effectiveness. Two mock-ups of the fin concept were created, one with

straight fins and one with fins that tapered to a more narrow opening, and one mock-up of the

corrugation was created. The corrugation method allowed for the beans to rest on top of the

corrugation and simply slide down to the rollers. The method that most successfully aligned the

beans was that with the fins that tapered to a narrower opening.

When determining which roller concept variants to consider for final design concepts, pre-rollers

and rollers were selected. The sideways roller concept and the bladed pre-roller concept scored

much lower than the latter. The sideways method complicates the separation of beans and pods

because the beans would not fall through the rollers. The bladed pre-roller method would greatly

increase the possibility of damaging the beans as they are loaded into the rollers. Therefore, these

two methods were not to be included in the final design selection matrix.

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The tumbler method compared the variations of separating, loading, and the overall performance

of the full systems. Since each tumbler concept entails a specific combination of each loading

method and separating concept, the net score is most important in this case. For example, the

single load can only be used with top loading and two stage separation. Thus the net score of the

three necessary concepts for each method were combined in Table 2.7 in order to determine the

optimal combination for the tumbler method.

Table 2.4: Separating concept variants for tumbler method

Table 2.5: Method concept variants for tumbler method


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Table 2.6: Loading concept variants for tumbler method

Table 2.7: Analysis of cumulative tumbler method concepts

Upon analysis of cumulative tumbler method concepts, the single load and continuous methods

were chosen for further analysis in the final design selection matrix, since they both received the

highest score (83). The contained method was not included in any further design matrices.

2.2 Data and Calculations for Feasibility and Effectiveness Analysis

Before proceeding with the design, it was necessary to evaluate each of the potential concepts in

terms of feasibility and effectiveness. Feasibility refers to the likelihood of actually completing

the design within our budget and skill set, while effectiveness refers to how well the design will

accomplish the required task. The evaluation for feasibility was concerned with cost of materials

and manufacturability, or the difficulty in actually creating a successful prototype, which

includes the complexity of the design. Since it is important that this machine can be operated by

any able-bodied adult, the weight of a load of beans was considered. Since each individual load

will weigh less than 10 lbs and it will not need to be lifted past the maximum of 80 inches, this

should be manageable for even the weakest operator. The evaluation for effectiveness was

concerned with the rate at which beans were successfully removed from their pods, along with

how well the requirements for weight and size were met. The first step in this analysis was to

benchmark currently available products that employ the bean removal methods used in the

preliminary conceptual designs. This benchmarking provided an understanding of whether or not

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a currently available design could meet the customer requirements. Beyond benchmarking,

inspections of potential designs were completed to evaluate the cost of materials and the

difficulty in machining the required parts.

2.2.1 Roller Method

One of the most popular roller-style bean shellers currently available on the market is the Little

Pea Sheller, by Taylor Manufacturing Company, Incorporated. This machine can process beans

at a rate of 3 bushels per hour, meeting the ideal processing rate established in the team’s

specifications. This indicates that this method of bean removal will be effective, and the machine

also meets the specifications for weight and dimensions. The drawback to this machine is its cost

of $475, so the goal for Team Green Bean would be to accomplish the same task at a cheaper

cost [8]. This leads to an evaluation of feasibility, specifically an evaluation of material cost and

manufacturability. The main area of concern is the method of bean removal, meaning the moving

rollers that pull the bean pod through and squeeze the beans out. Keeping this in mind,

manufacturability is not an issue at all. The only thing that needs to be done is to produce two

parallel rollers, both powered, that turn in opposite directions.


A currently available machine that employs the tumbler method is the TaMoCo Huller, also by

Taylor Manufacturing Company, Incorporated. The machine can process 7.5 bushels per hour,

far exceeding the specifications established by the team [8]. This indicates that the method will

be effective, but there are far more variables involved with this method than there are with the

roller method. This means that the method will be effective if executed properly, but perhaps not

feasible. Along with the uncertainty of feasibility, there are several moving parts involved with

this method. There is a rotating drum, a rotating shaft, and several beaters attached to the rotating

shaft that swing freely. The necessity of all of these parts increases the cost of materials, and

greatly decreases the ease of manufacturing. These additional difficulties make the tumbler

method the more difficult approach.


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2.3 Concept Development, Scoring and Selection

The following matrices have been prepared in order to determine the best combination of

subsystem concepts for the final design selection.

Four different concepts have been analyzed for the roller method, being as follows:

Concept 1: Rollers, hopper, and fins

Concept 2: Roller, hopper, and corrugation

Concept 3: Pre-rollers, hopper, and fins

Concept 4: Pre-rollers, hopper, and corrugation

Table 2.8: Roller method design concepts

Concept three (pre-rollers, hopper, and fins) received the highest rating in the analysis for roller

design concepts. In each selection criteria, this concept was rated equally to or higher than the

other three concepts. Thus, it can be concluded that concept three should be selected as the

optimal design for the roller method. A hopper was included in all four concepts, as the group

found it to be essential to the initial loading process. It was decided that fins will serve as the

best method to guide the beans towards the roller in the ideal position. Pre-rollers were

determined to be the best method to reinforce alignment when guiding the pods through the

second set of rollers that separate the beans from the pods. Since concepts one, two, and four

were close behind in their total score, it was decided that they will also serve as potential design

concepts for the roller method. Concept 2 (rollers, hopper, and corrugation) was omitted as a

design concept.

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Concepts five and six pertain to the tumbler method, and are as follows:

Concept 5: Single load tumbler

Concept 6: Continuous tumbler

Table 2.9: Tumbler method design concepts

In the analysis for the two concepts of the tumbler method, the single load tumbler concept

scored 0.3 points higher than the continuous tumbler. Although the group determined that the

continuous tumbler would be easier to use and have a slightly higher rate, the overall

performance of the single load tumbler was judged superior to the continuous tumbler. Ease of

use was said to be a secondary priority since the people operating this machine will most

commonly be experienced farm workers who are willing to work with their hands and mind at

the same time. Factors including certainty of success and versatility were determined to be more

important for this design. Further analysis of tumbler and roller methods has resulted in the

decision to discontinue both concepts for the tumbler method. This is due to the fact that both

tumbler concepts scored more than a full point less than the lowest scoring roller concept.

To select a final concept, the scores of each concept were compared, and it was determined that

Concept 3 scored the highest. This is the concept that includes a hopper for loading, fins for

orienting, and rollers with pre-rollers for bean removal.


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3. Final Design Concept

The final concept selection was to use the roller method as our means of shelling and separating

the beans and empty pods. The pre-roller design was selected to help assist in feeding the main

rollers as well as assisting in guiding the shelled beans to into the correct bin. The angled fin

orientation systems without the conveyor or roller assistance was selected as a simple and

effective way to orient the pods perpendicular to the rollers. The hopper was selected to provide

a simple and user friendly loading system. Figure 3.1 shows a solid model of the concept with

approximate dimensions (inches).

Figure 3.1: Final Conceptual Design

The conceptual design thus far has approximate dimensions that are open to change pending

results of testing and prototyping. The specific dimensions along with power transmission will

be selected in the future and presented in the final design report.

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Works Cited

[1] Price, George B. “Pea Sheller.” No. 43,864. 16 August, 1864.

[2] Hawkins, James M. “Pea and Bean Sheller.” No. 2,183,769. 28 July, 1938.

[3] Aikele, Andreas Jr. “Pea-Sheller.” No. 937,270. 27 July, 1908.

[4] Welborn, Woodrow W. “Vegetrable Peas and Separating the Hulls Therefrom and the

Like.” No. 4,024,877. 24 May, 1977.

[5] Taylor, George., and Taylor, Brett A. “Legume Sheller and Method of Use Thereof.” No.

12/205,094. 5 September, 2008.

[6] Taylor, George F. “Shelling Machine.” No. 5,052,992. 1 March, 1976.

[7] Young, Ellis R. “Pea and Bean Sheller.” No. 308,589. 25 November, 1884.

[8] Taylor Manufacturing Company, inc. “Green Pea and Bean Shelling Equipment”

11/14/2011. www.peasheller.com.

OHIO University Mechanical Engineering Conceptual Design Report

GOOD EARTH BEAN SHELLER

Team Green Bean

Mark Hritz

Michael Seiser

Sean Mefferd

Dan Knuckles

Andrew Janosik

Chris Allen

11-17-2011

GGK

Text Box

> Good start on CD and pretty good discussion of CD process your team is following. > Design report quality meets most expectations but could be improved by editing & better citations. > The evidence for CD scoring and selection ratings needs to be strengthened, images showing human interaction throughout all modes of operation need to be included to fully define the concept, and some physical mock-ups and calculations need to be completed before the concept can be fully developed and approved. Also, please include the completed CD selection checklist and evidence of project mentor feedback relative to final concept selection in your final draft of the CD report. > Please see comments throughout report and in CD presentation.

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1.1 Problem Statement for Concept Generation

Due to the gap between small gardens and large commercial farms, there is a need for automated

mechanical systems to perform time consuming tasks on medium scale farms. Farms of this size

include those run by independent farmers or non-profit farms that operate on a volunteer basis. In

particular, there is a need for a machine that will accept a variety bean pods as input and produce

shelled beans as output, with little to no work required by the operator.

The first step in concept generation was to identify the methods currently employed to

accomplish this task. The black box model was then used as a basis for each member of the team

to generate various complete system concepts. Upon identifying successful methods to remove

beans from pods, the black box was designated as a complete system that takes bean pods in and

outputs shelled beans. Each member of the team was required to define their complete system

including all subsystems. Circular brainstorming was then employed to identify the strengths,

weaknesses, and possible opportunities for improvement of each concept.

1.2 Patent Search

The patent search performed by the group resulted in a large variety of concepts that have been

previously designed. The patented concepts that were found varied in scale and method. The

patents also varied in age, with some dating back to the mid 1800’s. The patents were sorted by

method of operation and several of the most relate able patents to our concept design are shown

below.

1.2.1 Roller Method Patents

The first group of patents shown uses the “roller method” for de-shelling beans. In general,

patents for this method were the oldest. Also, these patented concepts are for a small scale

operation. Figure 1.1 shows a patented roller method “pea sheller.”

GGK

Cross-Out

GGK

Replacement Text

relevant

GGK

Comment on Text

Excellent job on the content in this section. You should include the actual patent numbers and citations for the images and ideas that are used directly from those patents.

3

Figure 1.1: Roller Method “Pea Sheller”; No. 43,364

The concept shown above is from 1864. It uses a hand crank to drive the main two rollers and a

conveyor feed system. The conveyor is driven by a pulley system. The gap between the two

rollers can be easily adjusted with a screw mechanism at the top of the machine. The beans are

separated from their pods after they move through the rollers. This method of separation is

different from most of the other roller method designs. The most typical method of separation is

getting the peas to stay on the feed side of the rollers while the pods move to the other side.

Another patented concept is shown below in Figures 1.2 and Figure 1.3.

Figure 1.2: Double Roller Mechanism

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In this design, two sets of rollers are used to de-shell the beans. When the beans go through the

first set of rollers, they are sliced open by the bottom roller. The top roller has ridges on it to

help pull the beans through. This process is shown in Figure 1.2. The next set of rollers are

placed close together so that the pods get pulled through but the beans are left behind as shown

in Figure 1.2.

Figure 1.3: “Pre-slicing” method

Another common design of roller systems is to have some type of gripping features on the

rollers. One patent that incorporates this design is shown in Figure 1.4.

Figure 1.4: Sheller with Studded Rollers

The above patent is for a small scale sheller which has two very small studded rollers.

5

1.2.2 “Tumbler” Method Patents

The next group of patents shown is for “tumbler” style shelling mechanisms. These types of

machines consist of spinning arms inside of a cylinder that break the beans out of their pods.

Tumbler style machines can typically handle a much higher load capacity than that of the roller

method machines. A simple design for a tumbler method machine is shown below in Figures 1.5

and Figure 1.6.

Figure 1.5: Tumbler Front View

Figure 1.6: Tumbler Side View

6

This machine, along with most tumbler machines, uses a screen with holes made to the proper

size for shelled beans to fall through and leaving the pod remnants inside the chamber. After all

the beans are shelled, the pods are removed from the device, and a new batch of beans can be

loaded for the next run. Tumbler method machines can become increasingly complex and

efficient. Figure 1.7 shows a more complicated design.

Figure 1.7: Advanced Tumbler Machine

This machine operates on the same basic principles as the previously shown mechanism but has

several additional features. First, this machine includes a two piece sliding screen that allows for

easy hole size adjustment. Instead of the shelled beans falling straight into a bin after falling

through the screen, the beans fall onto a conveyor. The conveyor moves the beans to an air

blower contraption that further sorts the beans from any small, unwanted debris that may have

fallen through the screen. The debris is lighter than the beans, and blows up into a separate

container. This process is shown in Figure 1.8.

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Figure 1.8: Blower Mechanism

Another patented design, shown in Figures 1.9 and Figure1.10 includes several different features

of another complex tumbler machine.

Figure 1.9: Alternative Tumbler Design

8

The first unique feature in this design is that the cylindrical drum both turns and rows the beaters.

The patent calls out a rotational speed ratio of the beaters to drum of 5:1. The drum spins in the

opposite direction as the beaters. Another different feature of this design is that the beaters have

free spinning forks at the ends. The patent calls out several different types of interchangeable

tips that can be used at the ends of the beaters for different applications. This design also

includes a method for further sorting beans from hull debris after the screen of the main drum.

The design uses offset shafts on pulleys to make two sets of screens vibrate. The vibration

motion moves the beans over the screens and sorts them accordingly into collection buckets.

1.2.3 “Shearing” Method Patents

The next method of patents is for the “shearing” method. This method of shelling beans is not as

prominent as the roller or tumbler methods. Only one patent was found for a machine of this

type. The design is shown in Figure 1.10.

Figure 1.10: Shearing Mechanism

This device uses a hopper to feed the beans down. Once at the bottom of the hopper, the beans

are grabbed by teeth from a spinning disc. The beans are then dragged across a stationary set of

teeth and are torn open. As the beans are freed from their pods, they fall down out of the

mechanism. The ground-up pods fall into the same area.

9


Initial concept generation started with each individual researching existing machines and

methods for shelling beans. This yielded two basic methods for shelling and separating beans.

The first method found was what will be called the “roller method” in which the beans are forced

through two rollers which squeezes the beans out of their pods almost like a toothpaste tube. The

second method that was found will be called the “tumbler method” in which beans are placed in

a rotating drum with a spinning shaft with fingers in the middle that will hit the pods and cause

them to break open. Once these three methods were bench marked a variation of the 5-3-5

brainstorming method was used to generate variations on was already being deployed in the

industry. This process yielded new ideas and variations on the two methods that were being

developed.

In order to further develop new ideas and variations, each team member was asked to come up

with as many full systems as they could for each the roller and tumbler method on their own.

This was a key step in allowing the team to have a very interactive and successful brainstorming

session. During the team brainstorming session, all of the complete systems were analyzed and

broken down into subsystems where appropriate. This break down into subsystems allowed the

team to look at a system as a whole and with interchangeable subsystems which generated many

new ideas, combinations, and variations on each system.

1.3.1 Roller Method

The roller method was broken down into three subsystems; loading, orientation, and rollers. The

loading subsystems included a top load system shown in Figure 11(a), a conveyor loading

system in Figure 11(b), and hopper loading system in Figure 11(c).

Figure 11: Roller method loading variations

The top loading system in Figure 11(a) consists of placing a handful of beans on the top of the

machine and an operator feeding them in by hand. The conveyor system in Figure 11(b) consists

of the machine being fed by an operator placing a load of beans in a container at floor level in

a b c

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what

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Well organized section with good level of detail. It would be helpful to show one or more representative system-level sketches from this early brainstorming.

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which a conveyor would transport the beans at a controlled rate to the top. The hopper system in

Figure 11(c) consists of an operator putting a load of beans into a hopper that would then feed

the machine at a controlled rate by the speed of the auger.

The orientation subsystem is a way to orient the bean pods perpendicular to the rollers so they

can pass through the rollers in the correct position. The orientation subsystem for the roller

method included an angled system with fins in Figure 12(a), an angled system with corrugation

in Figure 12(b), an angled system is fins and rollers in a Figure 12(c), and a flat system with fins

and a conveyor in Figure 12(d).

Figure 12: Roller method orientation variations

All of the systems in Figure 12(a-d) are all different methods designed to orient the beans in a

perpendicular manner to the rollers.

The rollers subsystem is the part of the machine that actually takes the full pods and separates the

beans from hull. The rollers subsystem included rollers in Figure 13 (a), rollers with pre-rollers

in Figure 13(b), rollers with pre-rollers blades in Figure 13 (c), and angled rollers in Figure

13(d).

Figure 13: Roller system variations

The roller system in Figure 13(a) consist of two rollers the are spaced closely enough together to

allow only the hull of the bean through the back side and force the beans out of the pod on the

front side. The rollers with pre-rollers in Figure 13(b) implement the same method but with

smaller rollers in front of the main rollers to help with feeding and bean separation. The rollers

with pre-roller blades in Figure 13(c) also implements the same method as the pre-rollers but

a b c d

a b c d

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also cuts the pods as the pass through the rollers. The angled rollers in Figure 13(d) are fed

vertically instead of horizontally and have the beans roll down the angled rollers after separation.


Unlike the roller method the tumbler method was not broken down into interchangeable

subsystems but three separate complete systems were generated. The three systems developed

were the single load system shown in Figure 14(a), the continuous load system shown in Figure

14(b), and the contained system shown in Figure 14(c).

Figure 14: Tumbler method variations

The single load system shown in Figure 14(a) the full bean pods are placed inside the inner

cylinder of the machine, as the machine is running the bean pods are broken up by the rotating

fingers and are separated through the wire mesh that the inner cylinder is made of while the pods

are contained in the cylinder. After the cycle is over the bottom tray with the beans is removed.

Once the beans have been emptied out of the tray it can be reinserted then by opening the door

on the cylinder the empty pods then be emptied into the try to be removed. The continuous load

system in Figure 14(b) uses the a mesh cylinder like the single load system but instead of

containing the pods inside the cylinder the pods slowly work their way through a much longer

cylinder and exit at the end. The contained system in Figure 14(c) does not have any separation

system and must have addition system or method in addition to itself.

a b c

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2. Concept Screening and Evaluation

2.1 Concept Screening

Through the team’s concept generation each different method was broken down either into

separate full systems or interchangeable subsystems. Each full system or subsystem was then

put into a matrix and compared to other variations based on ease of use, load handling,

manufacturing ease, portability, versatility, simplicity, rate, and certainty of success. Each

criteria pertains to the following: ease of use refers to how easy it is for the operator to use the

machine; load handling refers to how large of a load can be put into the machine with out it

jamming or failing; manufacturing ease refers to how difficult it will be for the team to make;

versatility refers to the capability to shell different types of beans; simplicity refers to how

simple the overall design is; rate refers to how fast the machine can separate the shelled beans

from their pods, and certainty of success refers to the team’s overall certainty if the machine can

be built and work. Each variation was scored on a 1-5 scale with 1 being the lowest, 3 being

neutral, and 5 being the highest.

2.1.1 Roller Method

The roller method compared the variations in each of the loading, orientation, and roller

subsystems to each other based on the previously stated criteria. Table 2.1 shows the matrix

used to compare the different loading subsystems of the roller method, Table 2.2 shows the

matrix used to compare the different orientation methods of the roller method, and Table 2.3

show the matrix used to compare the various rollers.

Table 2.1: Loading concept variants for the roller method

LOADING CONCEPT VARIANTS

SELECTION CRITERIA Hopper Conveyor Top Load

Ease of Use 3 5 2

Load Handling 5 5 2

Manufacturing Ease 4 1 5

Portability 2 1 5

Versatility 3 4 4

Simplicity 3 2 5

Rate 5 3 1

Certainty of Success 3 3 5

Improvement 4 4 1

Net 32 28 30

Rank 2 3 1

Continue yes no yes

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Good information, and it is acceptable the way it is written, but It seems that a simple table or bullet list would be a better communication tool for these 'definitions.'

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Please talk about your approach to comparing the core systems (rollers vs tumblers) before jumping right in. It appears that you decided that you could not compare them until each was integrated into a full system, so you used a filtering process to determine accessory components for each to allow the final comparison. If that is true, describe it first. Also, I am not sure why the loading system is unique between roller and tumbler method, but you have treated it separately. Please explain why that is necessary.

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Table 2.2: Orienting concept variants for roller method

ORIENTING CONCEPT VARIANTS

SELECTION CRITERIA Fins With Rollers With Conveyor Corrugated

Ease of Use 4 4 4 4

Load Handling 5 3 4 2

Manufacturing Ease 4 1 2 5

Portability 4 3 3 4

Versatility 5 4 4 3

Simplicity 4 2 2 5

Rate 3 4 4 3

Certainty of Success 4 2 2 3

Net 33 23 25 29

Rank 1 4 3 2

Continue yes no no yes

Table 2.3: Rollers concept variants for the roller method

ROLLERS CONCEPT VARIANTS

SELECTION CRITERIA Rollers With

Prerollers

With Preroller

Blades Side ways

Ease of Use 4 4 4 4

Load Handling 4 4 4 2

Manufacturing Ease 5 4 1 3

Portability 4 4 4 4

Versatility 4 4 2 3

Simplicity 5 4 2 2

Rate 5 5 5 2

Certainty of Success 5 5 3 3

Net 36 34 25 23

Rank 1 2 3 4

Continue yes yes no no

Upon completion of the roller method subsystem analysis, the team was able to determine which

concepts would be further analyzed in the final design selection matrix. For the loading

concepts, the team decided to use the hopper concept and omit the other two ideas. Originally,

top loading was going to be continued but since one of the goals of this project is to improve on

an existing design, the the hopper would be an improvement whereas the top loading concept

already exists. For the orienting concepts, fins and corrugation concepts were kept through the

final selection analysis, and the conveyer and roller concepts were eliminated due to their low

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Why? Without some explanation of the numbers used in the tables and what the team and customer thinks the real improvement is, you do not have a convincing argument.

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What were the differentiators that led to the low scores relative to the corrugated and fins. It seems to me that all you did was select gravity fed versus an active feed system. But I do not know what you are basing this evaluation on. I doubt you can know what will work until you build a mockup and test some beans to see if gravity fed orienting works. This should be an easy mockup and should be done before trying to justify a decision on the orienting subsystem.

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scores in the matrix. When determining which roller concept variants to consider for final design

concepts, prerollers and rollers were selected. The sideways an preroller blades methods scored

much lower than the latter; thus they were not to be included in the final design selection matrix.

Factors contributing to their low score include low relative certainty of success, versatility, and

manufacturing ease.


The tumbler method compared the variations in of separating, loading, and the overall

performance of the full systems. The rank and continue sections of the first three matrices have

been left blank. This is because each tumbler concept entails a specific combination of each

loading, method, and separating concept. For example, the single load can only be used with top

loading and two stage separation. Thus the net score the three necessary concepts for each

method was combined in Table 2.4 in order to determine the optimal combination for the tumbler

method.

Table 2.4: Separating concept variants for tumbler method

SEPERATING CONCEPT VARIANTS

SELECTION CRITERIA Single Load Continuous Contained

Ease of Use 4 5 2

Load Handling 3 5 2


Versatility 3 3 5

Simplicity 4 3 5

Rate 3 5 1


Net 24 27 21

Rank 2 1 3

Continue yes yes yes

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Again, without some discussion all you are saying is 'trust us.' Explain the logic of the argument which is organized in the table, do not just point to the table and say that is the reason. You would especially want to make the case that you have enough info to judge these alternatives. For example what is the certainty of success rating based on?

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Same comments as in above section.

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Table 2.5: Method concept variants for tumbler method

METHOD CONCEPT VARIANTS

SELECTION

CRITERIA Single Load Continuous Contained

Ease of Use 3 5 2

Load Size 3 5 3


Portability 4 2 5

Versatility 4 4 4

Simplicity 4 3 5

Rate 3 5 2


Net 29 29 30

Rank 2 2 1

Continue yes yes yes

Table 2.6: Loading concept variants for tumbler method

LOADING CONCEPT VARIANTS

SELECTION CRITERIA Hopper Top Load

Ease of Use 2 3

Load Handling 5 2

Manufacturing Ease 4 5

Portability 2 5

Versatility 3 4

Simplicity 3 5

Rate 5 1

Certainty of Success 3 5

Net 27 30

Rank 2 1

Continue yes yes

Table 2.7: Analysis of cumulative tumbler method concepts

Method Separation Loading Total

Single Load 29 24 30 83

Continuous 29 27 27 83

Contained 30 21 30 81

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Upon analysis of cumulative tumbler method concepts, the single load and continuous methods

were chosen for further analysis in the final design selection matrix, since they both received the

highest score (83). The contained method was not included in any further design matrices.

2.2 Data and Calculations for Feasibility and Effectiveness Analysis






includes the complexity of the design. The evaluation for effectiveness was concerned with the

rate at which beans were successfully removed from their pods, along with how well the

requirements for weight and size were met. The first step in this analysis was to benchmark

currently available products that employ the bean removal methods used in the preliminary

conceptual designs. This benchmarking provided an understanding of whether or not a currently

available design could meet the customer requirements. Beyond benchmarking, inspections of

potential designs were completed to evaluate the cost of materials and the difficulty in machining

the required parts.

2.2.1 Roller Method













the required parts.









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These scores are so close, and the uncertainty in your ratings so large, that you cannot use the small score difference to select one over the other. It basically says they are the same, so you would need to use another method to differentiate.

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Good introduction to this section. You will need to include the torque, speed and power requirements for the main roller and tumbler systems (likely from benchmarking) and a comparison of those requirements to human power, and/or the ballpark cost of a motor to provide those requirements.

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Just a repeat of last section

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the required parts.

2.3 Concept Development, Scoring and Selection

The following matrices have been prepared in order to determine the best combination of

subsystem concepts for the final design selection. Four different concepts have been analyzed

for the roller method, being as follows:

Concept 1: Rollers, hopper, and fins

Concept 2: Roller, hopper, and corrugation

Concept 3: Prerollers, hopper, and fins

Concept 4: Prerollers, hopper, and corrugation

Table 2.8: Roller method design concepts

Concepts

Concept 1 Concept 2 Concept 3 Concept 4

Selection

Criteria Weight Rating

Weighted

Score Rating

Weighted

Score Rating

Weighted

Score Rating

Weighted

Score

Ease of Use 10% 7 0.73 6 0.62 8 0.83 7 0.73

Load Handling 10% 6 0.60 5 0.50 7 0.70 6 0.60

Portability 6% 8 0.45 8 0.45 8 0.45 8 0.45

Versatility 21% 8 1.71 8 1.71 9 1.92 9 1.92

Rate 15% 6 0.90 6 0.90 6 0.90 6 0.90

Certainty of

Success 27% 6 1.61 5 1.34 8 2.15 7 1.88

Total Score 7.0 6.6 7.7 7.3

Rank 3 4 1 2

Continue? yes no yes yes

Concept three (prerollers, hopper, and fins) received the highest rating in the analysis for roller

design concepts. In each selection criteria, this concept was rated equally to or higher than the

other three concepts. Thus, it can be concluded that concept three should be selected as the

optimal design for the roller method. A hopper was included in all four concepts, as the group

found it to be essential to the initial loading process. It was decided that fins will serve as the

best method to guide the beans towards the roller in the ideal position. Prerollers were

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Same

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I am not convinced that you have the information needed to make final selection of a concept. If you think you do, be very clear about what you are basing your ratings on and why you think that is sufficient evidence. I really think you need some subsystem mockups before you can finalize your concept.

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I am confused about how this adds additional information compared to the subsystem analysis. What is different for the subsystems when evaluated as a system?

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determined to be the best method to reinforce alignment when guiding the pods through the

second set of rollers that separate the beans from the pods. Since concepts one, two, and four

were close behind in their total score, it was decided that they will also serve as potential design

concepts for the roller method. Concept 2 (rollers, hopper, and corrugation) was omitted as a

design concept.

Concept five and six pertain to the tumbler method, and are as follows:

Concept 5: Single load tumbler

Concept 6: Continuous tumbler

Table 2.9: Tumbler method design concepts

Concepts

Concept 5 Concept 6

Selection Criteria Weight Rating

Weighted

Score Rating

Weighted

Score

Ease of Use 10% 6 0.62 10 1.04

Load Handling 10% 8 0.80 7 0.70

Portability 6% 6 0.34 3 0.17

Versatility 21% 6 1.28 6 1.28

Rate 15% 7 1.05 8 1.20

Certainty of Success 27% 3 0.81 2 0.54

Total Score 5.4 5.1

Rank 5 6

Continue? no no

In the analysis for the two concepts of the tumbler method, the single load tumbler concept

scored 0.3 points higher than the continuous tumbler. Although the group determined that the

continuous tumbler would be easier to use and have a slightly higher rate, the overall

performance of the single load tumbler was found to dominate that of the continuous tumbler.

Ease of use was said to be a secondary priority since the people operating this machine will most

commonly be experienced farm workers who are willing to work with their hands and mind at

the same time. Factors including certainty of success and versatility were determined to be more

important for this design. Further analysis of tumbler and roller methods has resulted in the

decision to discontinue both concepts for the tumbler method. This is due to the fact that both

tumbler concepts scored more than a full point less than the lowest scoring roller concept.

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judged superior to

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3. Final Design Concept

The final concept selection was to use the roller method as our means of shelling and separating

the beans and empty pods. The pre-roller design was selected to help assist in feeding the main

rollers as well as assisting in guiding the shelled beans to into the correct bin. The angled fined

orientation systems without the conveyor or roller assistance was selected as a simple and

effective way to orient the pods perpendicular to the rollers. The hopper and auger combination

was selected to provide a simple and user friendly loading and feed rate system. Figure 3.1

shows a solid model of the concept with approximate dimensions (inches).

Figure 3.1: Final Conceptual Design

The conceptual design thus far has approximate dimensions that are open to change pending

results of testing and prototyping. The specific dimensions along with power source and power

transmission will be selected in the future and give in the final design report.

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This looks like a clogging problem waiting to happen. You could use an adverse consequences matrix to better include clogging and other 'failure modes' in your concept decisions. Also, as designed less than 50% of the rollers are used - you could significantly shorten the roller width to reduce cost and increase durability if you go with this type of method for 'aligning' the beans.

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I am not sure what value this adds if you already have the height needed for a gravity feed system.

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Sticky Note

I did not see any discussion of the transportation (portability) subsystem. This needs some conceptual design work.

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