“Classic Rocker”

Week #1

Date: 1/23/05

Team 7

Work Completed

During the week since the beginning of the semester, the team took inventory on what had arrived from the orders placed during the winter break. While three orders had been placed, only one item had arrived. The team received the squish switch from TFH (USA) Ltd. However, the audio components had not yet arrived. It was determined that the websites from which the CD player and speaker components were being purchased were unreliable for shipping. In order to fix this, the team found different websites (amazon.com and buy.com) to use, but the costs for the products at these websites were higher than at the initial sites used. The team had a squish switch and its gearmotor.

In addition to resolving the errors that occurred with parts ordering, the team went to pick up the chair that will be used for the project. A trip was made to Linens ‘n’ Things on Wednesday, January 18, where the chair was purchased. The chair was necessary to complete the week’s work because its range of motion needed to be analyzed and observed in order to determine how the chair will attach to the external aluminum frame to be constructed later. Pictures of the chair and a user were taken with the chair in its most backward position and also while at rest, both of which are shown below.

A common center point was used for analysis of the rocking motion, which was when the user and chair combined were at a centered, resting position. When the chair rocked either forward or backward, the horizontal distance of the top of the chair from the center point was measured; this provided the group with a comfortable range of motion for rocking. These pictures also helped determine at which point on the base of the chair the hinge mechanism will be placed. Finally, they were also used for analysis in Working Model 2-D software, which allows simulations of rocking to be created.

The gearmotor for the project was connected to a power supply and tested for consumed amperage. When just turning freely without any applied load, the motor used 1.18 A of current. When a small load was applied to the gearmotor shaft, the amperage increased slightly.

Speaker wire was purchased from RadioShack, which will be needed when the audio equipment arrives.

The internal frame of the chair was examined to begin determining attachment points for reinforcement and the rocking mechanism.

The team website was updated to include links for budget, timeline, final report, operator’s manual, and weekly reports for both the team and individuals.

Considerations were discussed for using 80/20 aluminum extrusions for the external framing of the design. Ordering this material is simple, there is a massive list of parts that are available, the shipping is quick, and the entire group could work on constructing the frame, not just the one person that was certified in the machine shop. It seems that using this material would be much more advantageous than using conventional aluminum pieces and welding them together in the machine shop, as well. Preliminary plans for the shape and dimensions of the frame were discussed, and AutoCAD was used in order to plan out a frame in a more concrete manner on the 80/20 website.

ID / Task_Name / Duration / Start_Date / Finish_Date
1 / Semester Starts / 1 day? / Tue 1/17/06 / Tue 1/17/06
2 / Inspect Parts / 2 days? / Tue 1/17/06 / Wed 1/18/06
3 / ELECTRICAL TESTING / 3 days? / Wed 1/18/06 / Fri 1/20/06
4 / Determine Current Draw of Motor / 1 day? / Wed 1/18/06 / Wed 1/18/06
5 / Determine Current Draw of CD Player / 3 days? / Wed 1/18/06 / Fri 1/20/06
6 / Determine Appropriate Power Supply / 1 day? / Fri 1/20/06 / Fri 1/20/06
7 / Order Power Supply / 1 day? / Fri 1/20/06 / Fri 1/20/06
8 / CHAIR ANALYSIS / 6 days? / Wed 1/18/06 / Mon 1/23/06
9 / Determine Reallife Centers of Mass to Compare with Experimental / 3 days? / Wed 1/18/06 / Fri 1/20/06
10 / Calculate Optimal Hinge Position / 3 days / Fri 1/20/06 / Sun 1/22/06
11 / Inspect Chair Frame Before Designing Reinforcements / 3 days / Fri 1/20/06 / Sun 1/22/06
12 / Determine Comfortable Rocking Displacement / 1 day / Mon 1/23/06 / Mon 1/23/06
13 / Determine Comfortable Rocking Speed / 1 day? / Mon 1/23/06 / Mon 1/23/06

Timeline 1: Work scheduled from the beginning of the semester until the first meeting.

Future Work

During the next week, the team hopes to do more in the way of physical testing and construction than just planning on paper. Designing of the frame will continue until a representative from 80/20 Inc. visits the lab on Friday, and so his/her suggestions for what the team can use will be considered then. Hopefully by or on that day, an order will be completed as to how much and which pieces from 80/20 will be ordered.

Also, the group is expecting the arrival of the CD player and speakers, hopefully by Friday. A preliminary wiring and testing will need to be completed on entire the audio system in order to determine what the maximum current draw will be. The speakers will be attached to the output of the system and the CD player will be wired to the power supply provided in the lab. A CD will be inserted once the power is turned on, and the volume increased to full power. At this point, the current draw displayed on the power supply will be recorded and used in the future when ordering a power supply for the entire device and for ordering a switch that will not burn out if too high of an amperage is passing through it.

Finally, the gear system to speed up the output of the gearmotor to a more sensible rocking speed will begin to be designed. This process will take some time to finalize, so the team will get started on it right away.

Once the 80/20 extrusions arrive in the future, the frame can be built, the chair can be mounted, and the motor can be attached in order to test the full current draw of the motor with a maximal amount of load on it. The development of the linkage bars, gearing up for the motor, and the hinge construction will all need to occur between now and when the chair will be tested, as well.

14 / FRAME CONSTRUCTION / 10 days / Mon 1/23/06 / Wed 2/1/06
15 / CHAIR FRAME CONSTRUCTION / 10 days / Mon 1/23/06 / Wed 2/1/06
16 / Finalize Design of Internal Frame Reinforcements / 2 days / Mon 1/23/06 / Tue 1/24/06
17 / Cut Parts for Internal Frame / 7 days / Tue 1/24/06 / Mon 1/30/06
18 / Weld Frame / 5 days / Thu 1/26/06 / Mon 1/30/06
19 / Attach Frame to Rocker / 2 days / Tue 1/31/06 / Wed 2/1/06

Timeline 2: Work scheduled for the second week

Project Review

The project seems to be on course for the week. Where some time was lost for the testing of the CD player and its total consumed amperage, time was still used to begin work scheduled to be completed this week (i.e., beginning the frame construction and hinge placement analysis). Decisions were already made to choose different sites to order the speakers and CD player, which will help out the team complete its early goals.

ID / Task_Name / Duration / Start_Date / Finish_Date
1 / Semester Starts / 1 day? / Tue 1/17/06 / Tue 1/17/06
2 / Inspect Parts / 2 days? / Tue 1/17/06 / Wed 1/18/06
3 / ELECTRICAL TESTING / 3 days? / Wed 1/18/06 / Fri 1/27/06
4 / Determine Current Draw of Motor / 1 day? / Wed 1/18/06 / Wed 1/18/06
5 / Determine Current Draw of CD Player / 3 days? / Wed 1/25/06 / Fri 1/27/06
6 / Determine Appropriate Power Supply / 1 day? / Fri 1/27/06 / Fri 1/27/06
7 / Order Power Supply / 1 day? / Fri 1/20/06 / Fri 1/20/06
8 / CHAIR ANALYSIS / 6 days? / Wed 1/18/06 / Mon 1/23/06
9 / Determine Reallife Centers of Mass to Compare with Experimental / 3 days? / Wed 1/18/06 / Fri 1/20/06
10 / Calculate Optimal Hinge Position / 3 days / Fri 1/20/06 / Sun 1/22/06
11 / Inspect Chair Frame Before Designing Reinforcements / 3 days / Fri 1/20/06 / Sun 1/22/06
12 / Determine Comfortable Rocking Displacement / 1 day / Mon 1/23/06 / Mon 1/23/06
13 / Determine Comfortable Rocking Speed / 1 day? / Mon 1/23/06 / Mon 1/23/06
14 / FRAME CONSTRUCTION / 10 days / Mon 1/23/06 / Wed 2/1/06
15 / CHAIR FRAME CONSTRUCTION / 10 days / Mon 1/23/06 / Wed 2/1/06
16 / Finalize Design of Internal Frame Reinforcements / 2 days / Mon 1/23/06 / Tue 1/24/06
17 / Cut Parts for Internal Frame / 7 days / Tue 1/24/06 / Mon 1/30/06
18 / Weld Frame / 5 days / Thu 1/26/06 / Mon 1/30/06
19 / Attach Frame to Rocker / 2 days / Tue 1/31/06 / Wed 2/1/06

Timeline 3: Updated future timeline.

Hours Worked

Adam Rauwerdink: 10

Sarah Philo: 8

Tom Dabrowski: 12