Monday, October 10, 2011

Autumn Images…

As Autumn arrives we are enjoying the end of the first full cycle of plant growth in and around The “L” Shaped House. In a effort to enhance this beautiful fall season Deb engaged the services of our friend Elizabeth Fischer who has a new business (Garden Junkie Designs) specializing in outdoor seasonal decorations.

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The two photos below show Elizabeth and her husband Andrew as they work to transform our front porch with a celebration of fall colors. Their work is really unique and beautiful.

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The front of The “L” Shaped House with our tall grass landscaping is shown below.

Autumn Yard 3

The last two photos show the back yard of the house. The first shows the “no-mow” turf and landscape gardens from a spot under our neighbor’s maple tree in the front yard.

Autumn Yard 1

The last photo shows the view of the back yard from a spot just beyond the garage. The “no-mow” turf has come a long way this first growing season. These photos were taken shortly after mowing it for the very first time (huh…?). Matt Wolfe recommended mowing the back yard late this fall to promote “fuller” growth next spring and to discourage rodent (moles and voles) burrowing this winter.

We’re absolutely loving the “woodsy” feel of the backyard landscaping…

Autumn Yard 2

Friday, October 7, 2011

Accessibility Lift…Design Process

The design for wheelchair lift in the “L” Shaped House is the result of a carefully considered engineering effort. The first phase of this effort was an extensive search for a commercially available lift. I think it is almost always better to buy than build when you are looking for an item like this. The commercial builders (presumably) have the advantage of having gone through many design iterations and their products generally represent the culmination of this process. We found many examples of lift assemblies available in the marketplace. Ranging from manually actuated portable lifts all the way to elaborate built-in elevators. Unfortunately none of the commercial lifts we found would fit in the space we have available. The collage below shows some of the lifts we considered in the search. The Liftboy lifting platform from Powerlift (upper left) comes as close to meeting our requirements as any of them…but in the end all are either too big or don’t lift high enough.

Commercial Lifts

The two lifts in the image below highlight the difficulty we faced while searching for a commercial lift to fit in the space available at the end of the stairs in the garage. Lifts generally fell into two categories; they were too wide or too long. It is also surprising how expensive these sorts of lifts are (nearly $6,000 for the blue one).

lift dimensions

While searching we came across a few examples of homemade lifts. A Canadian gentleman built the lift shown below (I can’t find his link again). The very clever cantilevered design addresses many of the space considerations we face in our home. It is especially interesting because the platform could be lifted quite high without requiring a large footprint. We spent some time playing around with this compelling configuration. His implementation is kind of crude…he does not use any bearings in the vertical slide. The sketch shows some possible improvements to the slide assembly but this design (compelling as it is) has a few disadvantages related actuating and controlling the lifting platform. That is…the overhead structure supporting the pulleys and cables gets tall and implementing a safe and simple control would be a little challenging (his is just a momentary switch). Furthermore I’ve found it challenging to get motor driven cable systems to operate smoothly. We considered the possibility of using a garage door actuator but could not find a small enough version anywhere.

Cantilever Concept (arrows)

Given our reservations related to controls for our lifting mechanism we expanded our search to include some other kinds of lifts. A number manufactures build lift assemblies that incorporate linear actuators in their designs. The linear actuators used generally include all sorts of nice control features like built in limit switches and “soft start” motors. Examples of these include the many different versions of lifts used to transport electric scooters for the disabled.  Unfortunately no one makes a lift rated for wheelchairs that lifts 48”. The image below shows two examples of these sorts of lifts. The Burr Handi-Lift is an interesting example that lifts to higher heights but they specifically exclude wheelchairs.

Scooter lifts

Our search turned up a fascinating possibility in the form of a personal watercraft dock lift. Several manufactures produce these lifts with both manual and electric actuators and integrated control systems. As interesting as this seems…this kind of lift has some disadvantages. The cantilevered platform has to be pretty robust (think tall) to accommodate the load and therefore ends up sitting something like 6” off the floor in the lowered position.

Boat Lift Concept

The simplicity and (relative) low cost of the mid-rise lift I purchased from Greg Smith Equipment for the third stall in the garage compelled us to look closely at this design. These kinds of hydraulically actuated scissors lifts are very common in industrial applications. The Atlas TD6MR has more than 48” of stroke and is capable lifting 6,000 pounds. Furthermore the hydraulic control system is quiet, smooth, safe, and runs off a single 120 volt outlet.

Atlas Scissors Lift

A scaled drawing of a scissors lifting mechanism tailored to the space available clearly shows that a single set of lifting arms results in a mechanism that would be unstable in the fully raised position. I produced the sketch below to inform Dan Oss and Byron Knapp (PICo’s engineering team) as we asked some questions about the structural elements of the lift mechanism. I was specifically interested in understanding the effects of lengthening one of the lifting bars.

Scissors 2

Dan quickly produced the CAD model shown here that shows how this structure works. The unequal length arms cause the platform to rotate slightly as the lift is raised. Carefully placing pivot points in the structure results in a platform that is tilted slightly forward at the bottom and slightly backward at the top of the travel. Even with this one extended lifting arm the structure looks a little unstable at the top of its travel.

Scissors concept 1 (highlight)

Working with this model quickly exposed the advantages of a “compound” scissors arrangement. In this configuration two sets of connected lifting bars push the platform to the same height while maintaining a comfortable (stable) spread even at the top of the travel. The lower sketch shows a possible motorized lifting configuration that allows the bars to clear one another as the platform is raised.

Compound Scissors Concept

As Dan’s experiments with the structure continued another possibility emerged. This time pairs of lifting arms tied together at their centers rotate and slide along a connecting rod as the stage is raised. This arrangement is superior to the previous in that the lifting bars are really quite short in relation to the stroke of the lift. It also provides for an uncluttered area between the bars for a possible actuator.

Compound Scissors Concept 2

The next sketch shows the real breakthrough in this process. Dan quickly discovered that combining a single full length lifting bar with two half length bars allowed for a structure that not only has fewer parts but also provided more flexibility for actuators. The sketches below show the mechanism as it quickly evolved. The first shows it with a full side panel supporting the arms while we see the greatly simplified support structure in the second.

Final Scissors Concept 2

The 3D CAD model below shows the lift assembly in its final form (the back side lifting mechanism is removed for clarity). Here we see the lifting platform fully raised with the hydraulic cylinder in place in the structure. The hydraulic actuator is positioned slightly off center on the lifting bar so that a cylinder with 14” of stroke produces 42” of  platform motion. The ends of the lifting bars are guided in linear slides and the cylinder is tucked snugly in-between. All of the elements in the structure are sized to provide a 1000 lb. lift rating which should easily accommodate our expected maximum 400 lb. requirement.

Final Scissors 2

We plan to use a hydraulic control system from Dalton Hydraulics. The MTE Hydraulic Pumping Station (250-730) is a D.C. powered system that we will connect to a deep-cycle battery with a “maintainer” charging system. The D.C. system will allow us to use the lift in the event we lose electrical power in the house. Multiple wired remotes will allow us to have push button control both on the platform and at the top and bottom of the lift.

Lift with control 2

C:\AutoManager WorkSpace\BEPLEY\M-Mteserver2,D-MTE PROD\Drawing\Working Copy\399\39901194-1.dwg Model (1)

Monday, September 26, 2011

Wheelchair Lift (modeled)

Over the weekend we straightened up in the garage and re-checked dimensions in the space where the wheelchair lift will be positioned. I also placed Dan Oss’s SolidWorks 3D model in the photograph below of the newly cleaned-up area using Photoshop. Arrows in the sketch show the lift platform movement as well as the wheelchair path. I think we are all now confident that this design is going to work nicely.

The next order of business is to “tweak” the structural elements of the lift mechanism as we decide on some important properties … like the size and shape of the rectangular steel tubing, and the thickness of the lifting bars. We might even subject the model to some simple finite element analysis.

Wheelchair Lift (in place cylinders notes)

Friday, September 23, 2011

Wheelchair lift (refined design)

One day of  review and refinements has resulted in this final(?) design for the accessibility lift in the garage at the “L” Shaped house. The first sketch shows the lift with the platform raised a little less than halfway up it’s travel.

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The second sketch shows the lift platform fully extended at the top of it’s travel. The transparent platform exposes the lifting mechanism under the far side.

Wheelchair Lift 9

The last sketch shows two hydraulic cylinders (crudely) placed in the assembly for clarity.

Wheelchair Lift (cylinders)

Wheelchair Lift

From the very beginning we have been paying close attention to accessibility issues at the “L” Shaped House. The original design of our home included a ramp from the garage to the mudroom entrance (here).  The elevation issue encountered early in the construction process forced us to change course and turn our attention toward a lift in the garage. After carefully considering many options we have decided to build our own lift mechanism designed by the world class engineering staff at Professional Instruments Co. Dan Oss, and Byron Knapp have come up with the ingenious scissors lift mechanism (that lifts the platform through center) shown in the Solid Works 3D model below. Hydraulic cylinders connected to the off-center vertical linkage (visible in the bottom two sketches) will actuate the the lift and requires only 12” of stoke to raise the platform to it’s full height of 41”.

Wheelchair Lift (arrow)

A refined view of this design showing one of the lifting cylinders in place below…

Wheelchair Lift 8

We plan to start fabricating the lift assembly shortly and hope to have it in place in the garage before the end of the year. The composite sketch below shows the lift mechanism superimposed on a photo of the end wall of the garage with some faint pen and ink additions to the design.

Wheelchair lift (components)

Wednesday, September 14, 2011

Meadow in the Making (Day 7)

By mid morning Schmitty and his crew had finished up all of the landscaping work at the “L” Shaped House and the planting beds were ready for mulch. Mulching by Mark showed up about 10:30 and got right to work installing the pine bark mulch with their amazing mulch blowing system. The small plants in much of the front yard made this method of application the best choice. The photo below shows the crew as they worked their way across the top section of the front yard.

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The video below shows the mulch blowing operation in detail.

Tuesday, September 13, 2011

Meadow in the Making (Day 6)

Schmitty and his crew are working on the dry creek bed that runs between our property and the Wright’s on the East side of the “L” Shaped House. Matt Wolf’s plan calls for nine weathered limestone boulders randomly placed throughout the creek bed. The buff limestone bed begins at the driveway and “meanders”  to the top edge of the rain garden. We plan to encourage the moss currently growing in this corner of the property to climb onto the rock bed and boulders.

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The extended video below captures the JLM crew as they work to place one of the last boulders near the top of the dry creek bed.

Buckthorn Eradication

Before and after photos showing the buckthorn eradication from our breezeway porch. This view shows just how thick the buckthorn had become in this area.

Before and After 2

Monday, September 12, 2011

Meadow in the Making (Day 5)

Schmitty and his crew are busy placing plants throughout the new meadow at the “L” Shaped House. The first two photos below show the front corner of the driveway during and after their efforts around noon today. They drilled holes all over the front lawn using a modified ice auger and place the plantings by hand.

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The next two photos show the rest of Schmitty’s crew working in the opposite corner of the front yard planting Blue Gamma grass using Matt’s home made plant spacing tool. The Blue Gramma, Bottle Brush, and Sweet grass arrived in “flats” as very small plantings. The individual plants are just barely visible in the foreground. Matt assures us they will take over the entire area nicely.

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The last photo shows the area between the houses as the JLM guys prepare to start planting the Quaking Aspen, Hazelnut, Witch Hazel, and Service Berry plants. This is going to be a wonderful area once we get everything established.

Meadow 13

Meadow in the Making (Day 4)

Schmitty and the JLM Landscaping spent the day (Friday) sculpting the new earthen berms and placing boulders in the front yard. Matt and I decided to use five large weathered limestone pieces as our “sitting rocks”  in the meadow. The photo below shows the crew working to shape and smooth the black dirt and sand “top dressing” spread across the entire front yard.

Meadow 11

The next photo shows Sarah from Gerten’s working to unload plantings from the truck load of landscaping materials delivered to the “L” Shaped House.

Meadow 10

The last photo shows the JLM crew stockpiling plant materials in a nice shady spot along the driveway.

Meadow 9

Friday, September 9, 2011

Meadow in the Making (Day 3)

Schmitty and his crew finished up the buckthorn eradication along the property line between our home and the Wright’s next door late yesterday afternoon. There were an amazing number of buckthorn plants growing there … as a matter of fact there was almost nothing but buckthorn in there.

The result is shocking!

Buckthorn Panorama

The photo below shows the Cat skid-steer taking a well deserved rest after a whole day prying tree roots from the hard clay soil. The hackberry, blue spruce, and maple trees are all breathing a huge sigh of relief  now that the buckthorn is gone.

Meadow 8

Amazingly … this little chipper turned all of the big piles into just one truck load of wood chips.

Good riddance!

Meadow 7

Thursday, September 8, 2011

Meadow in the Making (Day 2)

Day two of the meadow-in-the-Making operations at the “L” Shaped House finds Schmitty and his JLM crew hard at work preparing the front lawn and tackling the buckthorn out back. The first photo below shows the erosion control “wattle” material ready to be installed along the bottom of the front yard.

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Next … The tiller breaking up the top couple of inches of soil in the area where the meadow will be planted.

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The last two photos show the area between our home and the neighbor’s as Schmitty and his crew work to remove as much of the Buckthorn as possible. The area is absolutely overgrown with this invasive species and removing it is a really big task. While most of the trees are just a few inches in diameter there are more than a dozen trees bigger than 6”.

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The Cat skid-steer is the weapon of choice in this battle. Here Schmitty is preparing to ram the forks under one of the bigger plants as he “pries” it out of the ground.

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A video of the action…

Schmitty on the skid-steer

Tuesday, September 6, 2011

“L” Shaped Workshop…

Nearly 1 year on … We have the workshop in the garage set up and running!

The first photo below is a wide shot of the third stall with the workbench top fitted to the mid-rise scissors lift. The plan is to make this stall into a “convertible” workspace that will accommodate both auto maintenance and big wood working projects. The mid-rise lift provides a wonderful adjustable height base for the workbench. The only problem is what to do with the work surface when a car is in place?

Garage 46

The next two photos show the back wall of the third garage stall with our toolboxes, metal pegboard, and teardown bench in place. The galvanized metal pegboard from Wall-Control is absolutely great! Their product is well conceived and provides for not only tool storage and shelving … but light brackets as well. A few hours of organizing resulted in the arrangement seen here (it will probably evolve from here).

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Garage 44

The last photo here shows our first project nearly complete. We are building three Nordic ski waxing stations to be used during the High School racing season this year.

First … the plan (Google Sketch-Up)

Waxing Station Assembly

Next … the (nearly complete) project. The adjustable height 4’ x 8’ work surface made this effort convenient and fun!

Garage 43