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Can Crushers

Can Crusher Project
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Can crusher, United States Patent 4735387

Apparatus for crushing cans or the like comprises a conveyor formed from a plurality of endless chains cooperating with a fixed inclined crushing plate converging toward the discharge end of the conveyor. The crushing plate includes an actuator strip-like member hinged to the plate which when depressed engages an electrical switch to operate a drive mechanism for the conveyor. A can deposited into the apparatus depresses the actuator which operates the electrical switch to start the drive mechanism. The can is gripped by the chain conveyor and pulled downward between the conveyor and crushing plate flattening the can. When the flattened can exits the crushing apparatus the actuator is released stopping the drive mechanism. A support housing for the apparatus is provided with an opening for receiving cans which is spaced a distance from the crushing plate and conveyor to reduce the risk of injury.

Can project
Aluminum Can Crusher Project
Group Activities:

# Simulating a Can Crusher
# Human Factors
# Computer Simulation
# Building a Simple Can Crusher
# An Advanced Can Crusher
# An Electrical Equivalence


Activity 1: Simulating a Can Crusher
Product:
Develop a computer-based simulation that presents the force that is required for a can crusher to do the job.

Objectives:

* Understand basic types of motion
* Demonstrate a slider-crank mechanism
* Predict physical phenomena according to a mathematical model
* Use computers and software for modeling and simulation
* Analyze functional relationships (to explain a change in crank angle results in a change in stroke/displacement)

Procedure:

1. The teacher will demonstrate in the classroom the concept of slider-crank mechanism. The demonstration can be done by showing an actual model or an animation.
2. The teacher reviews theory and background: mathematical formulas and Physical concepts.
3. Students group into teams. Each team calculates the force needed in order for the machine to crush an aluminum can. Use Theory/Background page for the calculations.
4. Graph force vs. Displacement
5. Present the simulation to the class during presentation period.

Conclusion and Reflection:

1. Is the solution presented by your team the simplest?
2. What are the effects of constant velocity and constant Torque on the can crusher mechanism?

Activity Length:

* 1 class period for theory and background
* 2-3 lab periods for simulation design
* homework assignment time - presentation and conclusions
* 1 class period for team presentations

Activity 2: Data Collection - Human Factors
Students design an experiment to determine the force which an average human could exert to crush a can.
Procedure:

1. Plan the experiment that would measure a force. Use spring scale or other mass.
2. Apply the experiment onto a sample of your classmates and calculate the average force based on the collected results.
3. Plan a second experiment that would check how much force is needed to crush a can to 1 inch thickness?
4. Draw a free-body diagram of the system you used to calculate the force.

Conclusion and Reflection:

1. What type of human force is optimal, according to your experiments, for crushing a can?
2. Do you see a real need for generating a mechanical device vs. using body pressure?
3. Draw a free-body diagram that demonstrate the advantage of a slider-crank mechanism.

Activity Length:

* 2-3 lab periods for design, experimentation and data collection
* 1 class period for presentations

Activity 3: Computer Simulation
Based on Activities 1 and 2 students will design a computer-based simulation that represents the data. The teacher can choose between two packages:

1. "Interactive Physics" software package. Students can simulate forces and create graphs with the software.
2. CAD software to be used for building 3D models of the can crusher.

Activity Length:

* The length of this activity depends on the level of familiarity the students have with the software they are about to use. For advanced students: 1-2 computer lab periods are sufficient. For novices: 3-4 computer lab periods are required.

Preparations:
Teacher should obtain and install the software on the computers.
Activity 4: Building a Simple Can Crusher
Product:


Based on Activity 1, your task is to build a simple can crusher machine.
Objectives:

* Analyze a motion mechanism by physically constructing a model
* Design and build a simple machine
* Experience various problem solving strategies
* Use estimations through experiences
* Implement scientific and mathematical concepts into a working mechanism

Procedure:

1. In your team, develop various sketches for the proposed machine.
2. Select the best, simplest machine out of your proposals and get an approval from your teacher.
3. List and acquire the materials needed for the model, including specific measurements.
4. Build the machine.
5. Test the can crusher. If it doesn't work properly, find out what is the problem and fix it.
6. Your team will present the model to the class during presentation period.

Conclusion and Reflection:

1. How can you compare between activity 1 (simulation) and activity 4 (building the model)? Did the simulation help you prepare for the actual implementation?

Activity Length:

* 2-4 lab periods for building the model
* 1 class period for model presentations

Activity 5: Advanced Activity 1
Product:
Based on your experience with building a simple machine, your task is to upgrade the model and to develop a proposal for a commercial implementation. Your proposal should be presented as a letter to a manufacturer that presents your invention, including sketches and product specification:

o Where would you recommend people to put the machine (on the wall, as a part of the recycling bin...)
o What are the optimal dimensions of the device and why do you think so?
o What are the costs and materials associated with the product?

Choose one of the following upgrades:

* Use a CAM to resolve the variance
* Add a poker that would cause a decrease in the pressure needed to crush the can
* Design a "personal can crusher" - a machine that would use body weight as a factor of pulling the handle.
* Add a time dimension: optimize the machine to be able to crush X amount of cans within one minute. This machine should be enhanced to automatically load and unload multiple number of cans.

Activity 6: Finding the Electrical equivalence for slider-crank mechanism
Product:
Design an electrical machine that would use the slider-crank mechanism. The new machine should answer a realistic need (such as crushing a can, shaving or mowing your lawn).

Goal:
Students will design a simple device to crush aluminum cans using the concept of slider crank mechanism. This mechanism is used in real world applications as an internal combustion engine (e.g. cars, lawnmower, motorcycles etc.) and pumps.

Content Objectives:
Math & Science:

* Use linear, quadratic, and trigonometric functions
* Integrate mathematics as a tool for problem solving
* Use calculators or computers regularly to solve mathematical functions.
* Predict physical phenomena according to a mathematical model
* Use estimations through experiences
* Understand three basic types of motion
* Explore multiple solutions to a problem
* Understand measurement and systems of measurement
* Develop engineering drawing by hands skills such as isometric sketching, orthographic views, dimensioning, tolerances etc.

Computers:

* Understand basic computer operating and file systems (Mac/Win)
* Use CAD software for solid modeling and two-dimensional drawings
* Search and process information using the internet
* Use word processor and other presentation tools

Analytical

* Analyze a motion mechanism by physically constructing a model
* Analyze functional relationships (to explain a change in crank angle results in a change in stroke/displacement)

Communication

* Develop interpersonal skills
* Write a technical report
* Perform an oral presentation

Theory:

1. Slider Crank Mechanism
2. Mathematical Formulation
3. Displacement Analysis

Faculty

* Physics teacher - project leader
* Computer lab teacher - for the comuter-based simulation activity

Telecollaboration
N/A
Instructional Material

* Internet: for project's web page and other resources
* CAD or "Interactive Physics" software installed on a PC or a MAC
* Materials for building the can crusher model (see Activity 4)
* Physics and Math textbooks for theory and background

Further Projects:
Pivoted Block Brake System

# Horse Power
# Rotational motion
# Moment about a point
# Area of shoe
# Friction
# Pressure

Student Page

Inventions can start from the simplest idea. As simple as a machine that can crush your soda cans and save some recycling work and space. What would you need in order to design and build a can crusher machine? Besides basic construction materials (wood, glue, etc.), you would need to refresh your Math and Physics skills. Some imagination would help too...
You might say: "Who needs a can crusher?" Ok, maybe it isn't the best invention since the invention of the wheel, but it's only the beginning. This simple machine can be developed into a combustion engine for a lawnmower, or even a car. These machines belong to the family of the Slider Crank Mechanism.
During the project you will design and perform experiments that measure the force that is required for crushing a soda can. You will simulate a model and hopefully even build and test it in your lab. And who knows, maybe with some good public relations you'd find your can crusher on the shelves of your local hardware store.

Project Description
The can crusher project is divided to multiple team activities. Upon completion of each activity your team is expected to come up with a product. The product can be presented in various ways, depending on the specific activity:

* A written report,
* An oral presentation,
* A computer model, or
* An actual can crusher model


Aluminum Can Crusher
Mechanical Engineering / Physics Project
Developed by:
NJ Institute of Technology &
Bergen ETTC
Overview | Student | Teacher | Theory & Background |
Group Activities |
Resources | NJCCS/Skill Levels | Assessment |


Project Overview
Introduction
This multidisciplinary project is an attempt to create a link between Math, Science, Technology and Engineering. Students who participate in the project are presented with an open-ended problem (i.e., "design a can crusher machine"). Working in teams, students attempt to solve the problem, which is broken down to multiple activities. Each activity presents tools and concepts to be applied towards a solution. Learning is active, collaborative and creative - qualities that are all essential for a scientist/engineer to possess.

Goal
Students will design a simple device to crush aluminum can using the concept of slider crank mechanism which is used in real world application as an internal combustion engine (e.g. cars, lawnmower, motorcycles etc.) and pumps.

Project Length
Project length is dependent upon the number of activities the teacher choose to perform with the class. For specific activity length check Group Activities

Prerequisites
Students are expected to have prior knowledge in the following fields:

* Mathematics: Geometry, Trigonometry
* Physics: Principles of Motion
* Technology: CAD or "Interactive Physics" software is recommended; Presentation tools such as Microsoft PowerPoint, Publisher or other word processing software; Basic Internet and searching capabilities

Outline

1. Teacher presentation - the teacher presents the problem. The teacher than reviews the theory and background that is related and required in order to solve the problem.
2. Activity 1- the basic activity, simulating a can crusher mechanism, is performed in teams. Upon completion of the activity, team presentations and assessment is performed.
3. Advanced activities - the teacher might decide to perform more activities with the class. These activities are more advanced and include: data collection of human factors; computer simulation; an advanced model of the can crusher; and an electrical equivalent to the mechanical can crusher. For each activity, step 2 of the outline should be followed.
Theory and Background
1. Slider Crank Mechanism Geometry

2. Mathematical Formulation
Given with

R = the length of crank
L = the length of connecting rod
q = instantaneous crank angle

The connecting rod angle q can be determined by using the following formula:





3. Displacement Analysis

Activity 2: Data Collection - Human Factors Students design an experiment to determine the force which an average human could exert to crush a can.
Procedure:

1. Plan the experiment that would measure a force. Use spring scale or other mass.
2. Apply the experiment onto a sample of your classmates and calculate the average force based on the collected results.
3. Plan a second experiment that would check how much force is needed to crush a can to 1 inch thickness?
4. Draw a free-body diagram of the system you used to calculate the force.

Conclusion and Reflection:

1. What type of human force is optimal, according to your experiments, for crushing a can?
2. Do you see a real need for generating a mechanical device vs. using body pressure?
3. Draw a free-body diagram that demonstrate the advantage of a slider-crank mechanism.

Activity Length:

* 2-3 lab periods for design, experimentation and data collection
* 1 class period for presentations

Activity 3: Computer Simulation
Based on Activities 1 and 2 students will design a computer-based simulation that represents the data. The teacher can choose between two packages:

1. "Interactive Physics" software package. Students can simulate forces and create graphs with the software.
2. CAD software to be used for building 3D models of the can crusher.

Activity Length:

* The length of this activity depends on the level of familiarity the students have with the software they are about to use. For advanced students: 1-2 computer lab periods are sufficient. For novices: 3-4 computer lab periods are required.

Preparations:
Teacher should obtain and install the software on the computers.

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