Legless Rocker

Week #1

1/25/06

Adam Rauwerdink

Adam Rauwerdink Weekly Report

Work Completed:

During this week, the rocking chair was purchased from Linen n’ Things. Pictures of the chair during its rocking motion were taken for use in analyzing the frame. This picture was then used in Working Model 2D in order to create a scaled model. This model was used to find the optimal position for the hinge and the motor and cam system. The maximum torque was found to be less than 40 in-lb. This is slightly less than the torque value determined in general for the optimal design. The size of the cam was determined to be 1.25” in radius with a linkage bar of 15.3”.

The frame of the purchased legless rocker was also analyzed in order to determine what sort of attachment points for the frame will be available. The internal frame was very solid which will provide numerous locations for firmly attaching an aluminum frame.

ID / Task_Name / Duration / Start_Date / Finish_Date
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

Finally 8020 was looked at for use as framing material. The extruded tubing is very easy to work with and not to pricey, but purchasing brackets through 8020 is very expensive. We will likely purchase the brackets and bolts separately from Home Depot or a similar hardware store.

Future Work:

The next week will begin the building of the frames. If we go ahead with the purchase of 8020 the tubing will need to be cut to length and then assembled. Also the internal frame for the chair will need to be finalized as will the hinge design. If all of this is done through 8020 we should have the chair attached to the frame by some time next week.

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
20 / BASE FRAME CONSTRUCTION / 7 days / Thu 1/26/06 / Wed 2/1/06
21 / Finalize Base Design / 3 days / Thu 1/26/06 / Sat 1/28/06
22 / Cut Parts from Aluminum Stock / 3 days / Mon 1/30/06 / Wed 2/1/06
23 / Weld Base / 2 days / Tue 1/31/06 / Wed 2/1/06
24 / HINGE MECHANISM / 10 days? / Wed 2/1/06 / Fri 2/10/06
25 / Weld Reinforcements at Proper Location on Internal Chair Frame / 3 days / Wed 2/1/06 / Fri 2/3/06
26 / Design Hinge Mechanism / 2 days / Wed 2/1/06 / Thu 2/2/06
27 / Machine Hinge Parts / 3 days / Thu 2/2/06 / Sat 2/4/06
28 / Assemble Hinge / 1 day? / Sat 2/4/06 / Sat 2/4/06
29 / Attach to Internal Frame at Optimal Location / 2 days / Mon 2/6/06 / Tue 2/7/06
30 / Determine Height of Hinge Attachment on Base / 2 days / Mon 2/6/06 / Tue 2/7/06
31 / Weld Hinge Attachment onto Base / 2 days / Wed 2/8/06 / Thu 2/9/06
32 / Attach Hinge to Base / 2 days / Thu 2/9/06 / Fri 2/10/06

Project Review:

After one week of work I have the design for the frame nearly finalized and have a good idea as to where to acquire the necessary parts. The purchase of 8020 tubing and hardware from Home Depot should allow for substantial price savings. The frame built completely through 8020 cost $160, while using Home Depot hardware and work in the machine shop the cost should be cut to around $75. If 8020 is used for the internal frame and hinge as well we should have the chair attached to the frame soon. If this is accomplished we will ahead of pace.

Hours Worked:

1/16-1/25: 10 hours