Brian Log
Fri Jun 28, 2013
Backhoe: The design constraints of the Backhoe was that it must be able to dig a hole 6 feet cubed. As can be seen from the screenshots below the reach of the Backhoe's Boom, Stick, and Bucket is 9'10" and the depth is 6'5". The depth is taken from a horizontal boom. If the boom is declined then the depth that the Bucket can reach will be extended. The reach of the Backhoe allows the user to sit back away from the hole being dug at least 3 feet. For safety reasons the user would not want to place such a heavy piece of machinery next to the hole. The obvious result of the wall of the hole collapsing is thus significantly reduced. So even if 3 feet is excluded for safety 6'10" remains. Thus two out of the three dimensions exceed the design requirements of 6 feet. The reach of the Boom alone is 4'8.5". Thus with a reach that long the degree of rotation necessary to swing the Stick 3 feet off center to achieve a 6 foot range of motion is about 37 degrees.
Quick Attachment Assembly:
Finished working on the Quick Attachment for the Backhoe. I included a couple of flanges with bolt holes which will facilitate assembly of the Quick Attachment to the Bucket. By making the Quick Attachment detachable it is now possible to fabricate only one Quick Attachment part and employ it on other tools to be attached (auger, jackhammer, etc.), if so desired. Permanent attachement of the Quick Attachment is also possible.
Sat Jun 15, 2013
Here is my latest file File:Warehouse12.skp
Fri, June 14, 2013
The Boom has been simplified by removing the 30 degree bend. This was done in order to have the simplest manufacturing process possible for the first version of the Backhoe. In later versions the 30 degree bend might be reinstated.
Bucket:
There have been several designs for the Bucket. The Bucket was first designed with a curve back, as is common on most buckets. Keeping in mind the goal of the simplest manufacturing process possible and after consulting with Marcin, a flat panel design was preferred over the curve design since curving a 1/2" thick steel plate would be difficult. Thus the curved back was abandoned and has been redesigned to be constructed out of 8" x 16" stock plates 1/2" thick, welded together. Further work is required, namely the Tooth Assembly and the Quick Attachment.
The orientation of the Bucket is contemplated to be primarily as shown below; with the scooping action to be towards the user. However, it may be desirable to have the orientation of the Bucket reversed 180 degrees; with the scooping action to be away from the user. This is shown here [1].
Quick Attachment: I have come up with a design that is the simplest I can think of in terms of manufacturing and provides proper constraint in all degrees of freedom. It is an envelope system. A plate will be attached to the articulated attachment plate at the end of Stick. The item to be attached (i.e. the bucket, auger drill, jackhammer, etc.) will have an envelope attached at the attachment end. The articulated attachment plate at the end of the Stick will slide into the envelope in order to secure the item. An "L" shaped piece of angle iron may then be secured to prevent the item to be secured from sliding out/off of the articulated attachment plate. Securing my be attained by a pin and cotter pin combo or by nut and bolt. Once the item needs to be removed a simple removal of the pin and cotter pin or nut and bolt will release the item.
There are other means of quick attachment, but those means are either secured by intellectual property rights or involve complex manufacturing with specialized parts that would be difficult to produce from our stock supply of parts. For those reasons I have employed the envelope system.
Stick Hinge I have also started work on the hinge between the Stick and the item to be attached. I am trying to ensure full movement of the Bucket.
The preferred bucket would be the one third from the left (second closest) due to a desirable balance between volumetric capacity and the sharpest digging angle of the four choices.
Mon, May 27, 2013
Starting with User:Samthetechie's file File:Warehouse.skp I designed the Boom of the Backhoe.
The Joint: At the bend in the Boom is a 30 degree Joint. A bend will balance the depth and reach of the bucket. The degree of the bend need not be at 30 degrees. 30 degrees was selected merely for ease of calculations and based on the trig of a 30/60/90 triangle. The half inch thick Joint comprises two 8 inch wide plates welded together. On the concave side of the joint is a half inch diameter hole that will eliminate any stress concentration at that point. This is necessary to prevent stress fracture and sudden premature failure of the joint which could cause severe injury. The mounting holes in the joint are standard 1 inch diameter. If the joint needs to be made stronger more may be added.
The Wedge: On the interior of the Joint is an optional quarter inch thick Wedge. The wedge may fill in the gap between the 4 inch tubing. If used the Wedge should be welded to the tubing. Its purpose is to strengthen the Joint by making both sections of tubing one piece. I also included a plate for attaching the hydraulic cylinder which will control the vertical movements of the Boom and Stick. The location of this plate is not fixed, however, it is currently located on the Joint in order to minimize the stress on the joint.
The Stick: The present configuration of the Stick has a pivot plate arranged to act as a fulcrum. This arrangement allows the Stick to have maximum range of motion. Further, the increased length of the Stick extending above the Boom increases the lever arm of the hydraulic cylinder which reduces the force needed to be exerted thereby. This will increase the durability and lifespan of that cylinder.
Next item to be worked on will be the Bucket and its attachment to the Stick. The sketchup file of the Stick and the Boom can be found at File:Warehouse11.skp while a picture can be seen below.
Sat, May 25, 2013
Hey Brian, thanks for collaborating with User:Marcin and User:Samthetechie on the Backhoe today, can you write a few notes on your findings / approach for today. Also, you might find these new parts I uploaded helpful / interesting: File:Boom.skp and File:Stick.skp
Fri, May 17, 2013
Talked to Marcin about Backhoe Stick and Boom Concept Specification. Started work on the backhoe stick and boom. Made stock parts and did an assembly of the boom.
Links to Nickle Iron Battery (NiFe Battery)
Edison Patents
http://www.google.com/patents/US678722 http://www.google.com/patents/US692507
Helpful Youtube Videos
The author of the video "edsworkshop" has several videos from 1.0-1.15 on how to make a nickle iron battery. Below is the link to the first video.