Introduction

Hydraulics is the branch of science and technology concerned with the conveyance of liquids through pipes and channels, especially as a source of mechanical force or control. Fluid mechanics provides the theoretical foundation for hydraulics, which focuses on the applied engineering using the properties of fluids. In fluid power, hydraulics are used for the generation, control, and transmission of power by the use of pressurized liquids. Hydraulic topics range through some parts of science and most of engineering modules, and cover concepts such as pipe flow, dam design, fluids and fluid control circuitry and pumps.

Mechanical advantage is a measure of the force amplification achieved by using a tool, mechanical device or machine system. Ideally, the device preserves the input power and simply trades off forces against movement to obtain a desired amplification in the output force. Machine components designed to manage forces and movement in this way are called mechanisms. An ideal mechanism transmits power without adding to or subtracting from it. This means the ideal mechanism does not include a power source, is friction-less, and is constructed from rigid bodies that do not deflect or wear. The performance of a real system relative to this ideal is expressed in terms of efficiency factors that take this into account

Problem

Design and engineer a mechanical device that is powered by hydraulic (syringe and water) that includes levers and moving parts that will propel a ping pong ball to complete the 2 levels of the “Hoop Shoot Challenge”. The final product for this challenge will be laser cut from wood. It is also possible to 3-D print parts as needed but the main body of the device will be processed on the laser engraver. All prototyping will be done utilizing K’nex and cardboard. The majority (70%) of the final product must be main from 3-D printed and laser cut items. The students will also be given a 24 gear package but are encourage to design their own gears.

Limitations and Considerations

1.      The device should be no bigger than 12 inches wide x 12 long x 12 high with all axis compacted.

2.      The power from the syringes and water will be used to maneuver the mechanics of your device. You cannot aid this in any way. You may load the ping pong ball into the devises gripper or holding mechanism.

3.      No item may be launched or thrown along with the ping pong ball. The ball must be the only item that leaves the device.

4.      All groups will be given 6 - 30 ml, 3 – 20 ml, and 3 - 12 ml syringes. You do not have to use all of them but you can only use your 12. Tubing will be supplied on an at need basis. It is permissible to trade in your 20 and 10 for 30 ml syringes.

5.      Other materials available on request: string, pipe cleaners, round wooden dowel, binder clips, paper clips, rubber bands, craft wire, glue (hot and wood), zip ties, and brass paper fasteners (1/8 hole diameter). Any other materials that are not listed or laser cut and 3-D printed must get instructor approval prior to use.

6.      The material thickness for the wood to be cut is 0.20 inches and the cardboard is 0.177 inches. There is no cubic inch limitation for the 3-D print material but try to be conservative. Limit wall thicknesses to 0.063 inches to 0.125 maximum.

7.      T-slots for the syringe plunger and brackets for the body may be the best application for fastening the hydraulic cylinders in place. It is permissible to have multiple location to place the hydraulic cylinders that way your device is adjustable for the various challenges.

8.      Slots placed in targeted areas of your device can change or limit the range of motion in a calculated manner.

Evaluation

Engineering Design Notebook - The students are required to have one journal entry per week that include: brainstorming, construction notes and progress, encountered problems and solutions, and areas of concern.

Assessment Instrument–Engineering Design Process Worksheet Rubric

Resources:

Mechanical Arm  http://jefenry.com/main/MechanicalArm.php#plans

Hydraulic robotic arm with syringe  https://www.youtube.com/watch?v=6kk335WDglE

Photos:

Prototyping for The Lay Up Challenge

Around the Horn Challange

Student Example

Student Example 2