1. Design Of Post Tensioned Slabs On Ground 3rd Edition Manual Muscle System
2. Design Of Post Tensioned Slabs On Ground 3rd Edition Manual Muscle Cars

The Bin-Dex Open Source Library is Now Available! The is an Open-Source Labeling System based around Off-The-Shelf Akro-Mils storage cabinets. Many people already have Akro-Mils cabinets as they are one of the most common brands on the market. The Bin-Dex system uses custom extruded Rails that clip on to your existing Akro-Mils cabinet. These rails connect all the bins in a row into a single tray. So, you can see everything in that row in an instant.no more hunting!

PTI DC10.1-08 - Design of Post-Tensioned Slabs-on-Ground, third edition with PTI DC10.2-06 - Construction and Maintenance Manual for Post-Tensioned. Association and is certified by the Post-Tensioning Institute (PTI). We perform all our work Let Our Design Build Team Take care of YOUR entire project! C New Construction of Post. Slab-on-Ground Design by Using the PTI Ken Bondy Method. Biggest Single U.S. Market for Post-Tensioning Tendons. Edition published in 1980, 2nd Edition in. Post-Tensioned Concrete Slabs-on-Ground Author: Ken Bondy Created Date.

Also, it provides large continuous flat surfaces for color coding and labeling. You can download a curated labeling scheme for whatever you want to organize, or just download a template that corresponds to the storage cabinet that you own and build it yourself! If you think others would like your solution, share it with the community!

The Bin-Dex Project: Open-Source Organization The is a joint-effort between AXN-RXN Engineering and NHXT Design. It is an effort towards creating an expansive system of curated organizational themes.

What does that mean?!? We are creating a color-coded labeling system for existing off-the-shelf small parts bins. Want to organize your fasteners? Download a 'Fastener Layout' from the Bin-Dex library, print it out, and stick it on your storage box.

Electronics, Fishing, Scrap Booking, Medical, Bicycle Parts, the list goes on and on! The Bin-Dex Labling Concept Here we see the same Akro-Mils storage cabinet with the Bin-Dex Rails attached and a color-coded labeling scheme applied. This specific scheme is a fastening kit for standard machine screws sized #4 through #10 in varying lengths. Also included in the labels are Icons which help direct you to the correct parts.

From a distance you can tell that all your screws are Blue, all your nuts are Red, washers in Grey, with tapping tools and accessories in additional colors in the bottom row. The Physical Bin-Dex Parts The Bin-Dex system works off of an existing Akro-Mils parts cabinet, but then adds custom Rails and Clips. The Rail extends across the entire row of bins and connects them all with snap-on Clips. Now, your row of parts bins opens just like a tool box! You can see all the contents in that row in a single glance.

The Bin Dex Rail has two areas designated for labeling. The upper labeling area can be uses for specific part call-outs and labels. The lower labeling area can be used for category badging, or for additional parts labeling if you choose to divide your bins in half.

Labeling Scheme: Resistors Resistors are a perfect part for the Bin-Dex system. They are small, color-coded, and have tons of different values. Get them mixed-up and you are spending hours testing each resistor with a multi-meter to figure out the value.

The Bin-Dex Resistor Library has every common resistor value and a color graphic to show the appropriate banding. Just find the picture that matches your resistor!

This particular Scheme fits a 32-value resistor kit. We used bin dividers in an Akro-Mils 16 Bin unit to fit 32 different resistor values.

Mechanical CAD: SolidWorks Assembly Three separate events are required to successfully fill a bubble and allow it to descend to the floor without bursting. It requires Gas, Soap, Bubble Release and an Electric Arc.

Each one of these events must be accurately timed relative to each other. An easy way to do this is to use a microcontroller such as an Arduino. However, the artist is not programming savvy and wanted a simple machine that just worked. So, each even it timed via timing cam located on the main shaft of the mechanism. These cams engage micro switches that control a solenoid gas valve, a peristaltic soap pump, and a DC-AC solid state relay to control the electric grid. The motion of the Bubble Nozzle is controlled via a sort of 4-bar linkage and an additional cam.

AXN RXN handled the mechanical design and analysis for The Slow Inevitable Death of American Muscle. This piece is a super-slow motion simulation of two cars during a front-end impact. The cars start inches away and slowly crush into each other over a period of days, weeks, or months. How much energy is involved in a high speed front end impact?

How much force would be needed to simulate such an impact? How strong does the steel framework have to be to contain those forces? AXN RXN was responsible for determining the amount of force needed to simulate such an impact and to design the structure able to withstand this force. Government car crash data is available which states the average amount of crumpling involved in a 40mph head-on collision. From these numbers and the weight of the vehicles one can calculate the average force required for such crumpling.

For our case it turned out to be 40-tons. The Slow Inevitable Death of American Muscle has been installed in Chicago, Louisville, Marfa, New York, China, The Netherlands, Belgium, Germany, and Switzerland. Gear Reducer / Hydraulic Pump An elecro-hydraulic reducer was designed to power the sculpture.

An electric motor spins at 1000 rpm at the beginning of the gear chain reduction. After eleven sets of reductions though the Ford V8 timing chains, the output spins at one-half of a revolution per minute. The eccentric shaft output works a hydraulic pump back-and-forth to suck oil out of the reservoir and supply hydraulic pressure to the ram cylinders. The combination of mechanical and hydraulic reduction allows each car to move at a super-slow 0.005 inches per minute.

Is a division of Brunswick Corporation that specializes in pontoon boats. A redesign was necessary for the Harris line and AXN-RXN along with were contracted to take on the face-lift. Harris has an existing fiberglass steering console that they wanted to get more life out of. So, Launch penned several different designs working off of this existing part. AXN-RXN handled the turning the design sketches that Harris selected into manufacturable parts that could be produced for an upcoming show. All parts and assemblies were designed for manufacturing in SolidWorks. Processes and materials included vacuum-formed ABS, fiberglass, sheet metal and CNC milled aluminum parts.

Off the shelf LED displays and hydraulic steering columns were fit into the console. Harris Marine - SolidWorks Assembly Rendering The Harris Marine dash was built off of a pre-existing fiberglass control pedestal submitted by the client. Industrial Design talent by Launch Product Development created surface models and rederings to show Harris different design directions. While surface design data is sufficient to show what a product might look like, little detail is given to how parts will be fabricated and how they all assemble together. This is where AXN-RXN Engineering comes in. Ariel Schlessinger's Dancing Chairs kinetic sculpture is simple in concept. Two old wooden chairs perform a series of movement together in the center of the room.

Using nylon cords, the two chairs pull on each other in order to come together, tip up, fall backwards, and right themselves again in a repetitive sequence. Ariel figured out how to route the cords in order to get the movements he wanted, but automating this process was a different matter. AXN-RXN designed a system of DC gearmotors, electric clutches, bearings and spools that were able to winch the chairs together into position, but then also release on command to let the chairs drop to the floor at the right time. Rugged sensors were developed that would allow the chairs to be pulled to the correct position, but were designed to not react when they weren't supposed to, like when both chairs tip and slam onto a concrete floor. All images courtesy of Yvon Lambert Galleries & Ariel Schlessinger. The Gravity Flower is an instrument devised by Andy Cavatorta. A four-harp system was commissioned by Bjork for her Biophilia tour.

The four harps swing in a steady rhythm and are plucked by a stationary arm at the lowest point of their swing. Different notes can be played by placing the strings around the outside circumference of the harp. A computer controlled motor located in the base indexes the harp to the appropriate string before it swings back past the pick. With all four harps swinging at the same time, a melody can be played. Barrel Harp Detail One interesting challenge was to sonically isolate the harp from all the other vibrations in the system.

In order to only hear the harp's strings and sound board resonate, all the other vibrations from bearings, bushings, motors and support structures had to be removed in order for them not be picked up by the acoustic microphones. Custom mounting hubs were designed to house layers of specific sound-deadening materials so that there was not a direct connection between the harp and the surrounding mechanical system. Tuned Chalice - Solenoid-Based Striker Here are three tuned Stella Chalices with solenoid-based strikers.

The solenoid-based striker had a bunch of advantages over other designs. A solienoid is mechanically simple and only involved a magnetic housing and a steel bolt. By throwing a current through the solenoid, the bolt shoots in a direction like a bullet out of a gun. By varying the intensity and duration of the current pulse to the solenoid, you can adjust the musical volume of the strike. An Arduino microcontroller makes this a snap, because it can all be done by just adjusting lines of code.

The BrewStaff Wizard Clip is an internal novelty product designed by Karl Biewald. It is a simple one-piece plastic clip used for the party game. In this game your build up a tall Wizard's Staff from beer or soda cans.

So, you finish one beer, then snap a Wizard Clip onto the top of your empty can. Then, snap your fresh beer on top of that one.

You now have a Mini-Staff! Continue in this manner and eventually you have a tall Wizard's Staff to walk around with! The BrewStaff Wizard Clip received a Kickstarter Staff Pick endorsement and a few product plugs from YouTube channels and Twitter. But, in order to hit the funding goal for production, it needed far more backers. Why such an incredible product idea failed will forever be a mystery! The Violina is a musical robot devised by sculptor and commissioned by Stella Artois.

The Violina is a stringed instrument in the Stella Chalice symphony. Eighteen tuned chalices can be bowed independently to create a range of notes. The real trick of this instrument is to be able to duplicate the subtle touch of a human's hand as they draw a bow across the edge of the glass. If the angle and pressure are not just right, the glass won't resonate and create a sound. AXN RXN was responsible for the electro-mechanical prototyping of the spinning hoops and chalice actuating arms.

All parts were fabricated in-house by AXN RXN in Brooklyn. Materials are solid maple, aluminum, acetal, and mild steel. CNC machining of maple The critical parts of the Violina's rotating wheels are machined from solid maple.

Machining wood is more of an art form than metals due its inherent grain direction. While a piece of aluminum can be set up in any orientation and produce the same results, wood may chip out or burn in one orientation, and be too weak to withstand a load in the other. Using CNC milling equipment, six arcs of the Violina wheel could be machined from one slab of maple. This helps save time a material over cutting each independently on a band saw. Horse Wheel Fabrication The 'Horse Wheel' is the outermost spinning body in the Violina assembly. It is responsible for supporting the tensioned bowstrings that cause the Chalices to resonate. Made of solid maple and aluminum, it has to be accurately machined and balanced in order to produce a consistent note.

Do to it's large diameter, each ring layer is actually made up from six separately machined arcs. With three layers in each hoop, twelve maple arcs plus six aluminum arcs have to be assembled together without compromising strength nor balance. By overlapping the seams of the arcs and connecting with steel dowels, the entire assembly becomes accurately round and strong enough to take the tension form the bow string. SolidWorks Layout The Blunderbuss started with a SolidWorks assembly model. We based most ergonomics off of common mountain bike dimensions.

Wheels and tires were borrowed from a downhill racing bike as well as the brakes, hubs, and headset bearings. The moped was designed to be bolted together from three main components: the body, the front forks, and the frame. The body is fabricated from two formed lengths of aluminum sheet which are fastened together by rivet strips to form a tubular structure. The front forks are made from simple steel tubes with CNC machined cross braces and dropouts. The main U-shaped frame resembles the Indian frame on the previous page and is designed to be CNC bent from a single length of tubing.

Blunderbuss Fabrication The Blunderbuss Alpha Prototype was fabricated in Brooklyn. This was a quick and dirty version that would help validate our design and check out the ergonomics. Certain short cuts were made for fabrication purposes. We welded the two body halves together rather than using rivets.

The U-shaped frame was welded from bent sections rather that using a single length of tube. The headlight and taillight caps were hand fabricated from aluminum rather than the vacuum formed plastic pieces in our model. Blunderbuss Development We've learned a number of things from the prototyping effort. The overall weight of the bike is around 120lbs, which is light for a moped, but too heavy to use bicycle components. The tires and brakes are not suitable for that much weight, so we've upgraded to minibike brakes and are sourcing off-the-shelf moped wheels and tires.

The next step is to bring the moped in to a licensing station and find out what else we have to accomplish before we can legally ride it on the road. Perhaps for the Beta prototype we will focus on weight savings or go directly to an electric power train.

This image shows a mono-shock pushrod suspension in the works. The Coincidence Clock is part of a sculptural installation by NYC artist Marci MacGuffie.

Design Of Post Tensioned Slabs On Ground 3rd Edition Manual Muscle System

It keeps track of coincidence probability rather than the standard seconds, minutes, hours. The innermost circle counts half-days as it rotates through 180-degrees. The outermost ring indexes 1/12 of a rotation (one month) for ever 30 days of the center. In addition, the Coincidence Dial indexes once every two months.

At the end of 26000 years, the rectangular Season Symbols rotate to flip the season direction. All photos courtesy of Marcie MacGuffie. Inhale by Bruce Pearson is a kinetic light-based sculpture based on the relative motion of two silk-screened glass plates.

When the panes of glass are perfectly in line, the statement 'Inhale' can be in the shadows. When the panes are not in line, a delicate moving pattern of shadows is observed. This is a very subtle piece that moves via an electronically controlled two-motor bed mounted to the ceiling. Cables descend from this bed to suspend the uppermost pane of glass.

An Arduino microcontroller is programmed with multiple movement patterns which all return to the home position at the end of their movement. The home position is defined as the center of the bed's movement and also the point where the panes of glass are perfectly in line and reveal the illuminated text. The Whirling Dervish is a robotic sound installation by Andy Cavatorta. It works just like those corrugated plastic tubes that you used to spin over your head and make howl when you were a kid. If you trim those tubes to specific lengths you can make the tubes howl specific notes.

Andy took this concept and applied it to a robotic sound installation. Fourteen independently controlled 'Whirley Wings' spin the howling tubes at prescribed speeds. These fourteen wings can produce a wide range of notes and can be either played directly through a keyboard, or through a pre-programmed composition.

The Whirling Dervish was designed and built in about two-weeks for a TED event in Palm Springs, CA. Andy was a featured artist and decided to construct the Dervishes for the event. A 24-hour drive from Brooklyn to Palm Springs got the piece there just in time for load-in. SolidWorks rendering of Whirling Dervish The Whirling Dervish was designed and engineered using SolidWorks. Due to limited time, the layout for the Whirling Dervish was much more focused on ease of fabrication and packaging than pleasant aesthetics. The original Whirling Dervish piece was envisioned as a field of spinning wings mounted on tall tripods. We soon found out that we were given a 12' x 16' indoor space with 12-foot ceilings.

In order to accomodate this space, AXN RXN packaged the spinning arms vertically in two rows of shelves. This design could be easily fabricated, assembled and fit within the space we were given.

The Precis Velo core training system is a fitness device developed by a physical therapist/ ex-bike racer/entrepreneur. He recently published a fitness book describing core strengthening exercises for the racer-in-training. To go along with the book he also developed a fitness system that could be used to perform the variety of exercises that he discussed.

In order to sell his idea, he felt that the system needed to be easier to use and have more design presence to attract prospective investors. The system is made up of three main components: 1) The Working Surface 2) The Base Frame, and 3) The Handle Bar Apparatus. The working surface is the blue sheet metal form that the user rolls an exercise ball against. This form can be detached from the Base Frame and reversed in order to switch from a convex or concave rolling surface. The Handle Bar Apparatus is essentially two hand grips that can be attached at different positions around the Base Frame depending on what exercise is being done.

All renderings and concept boards by Jeffery Popowski. Existing Precis Velo Prototype The pictures above show the initial setup of the client's original system as well as a typical exercise one would perform. Detailed notes and video were taken of the existing construction and assembly methods as well as all of the exercises that could be performed. An Industrial Design colleague and I brainstormed different product concepts that met the clients exercise requirements, simplified use, and met the production budgets.

These various concepts were then pooled together into three different product concept boards and presented to the client. Concept One The first of three product concept offered was a conservative design the bears much resemblance to the original system. This concept uses a bent wood laminate as the exercise surface and cast aluminum or molded plastic end caps rather than the original all-sheet metal design.

We also included an adjustable wing idea that allows the user to vary the incline of the exercise surface. The handle bar apparatus in this concept was left exactly as it was the original unit except for a quick-release connection where it met the base frame. The square tubing of the base frame was rotated 45-degrees to easily mate with a quick-release attaching concept. Concept Two Concept 2 is a significant departure from the client's original design. From the research phase we learned that it was not necessary for the user to detach and reverse the large working surface in order to conduct all the desired exercises.

If both the convex and concave shapes were put on one side of the form, the user would not have to pick up the awkward form and flip it around to change exercises. This method also allows adjustment notches to be molded into the form that would fit snugly around the square base tube of the Handle Bar Apparatus. So, to change exercise positions, the form need only be tipped up a couple inches, rotated to the desire orientation, then dropped back into position.

Ease-of-use is dramatically improved. This form can be manufactured by relatively inexpensive blow or rotationally molded means and reduces cost even further by totally eliminating the need for a Base Frame. A more fluid Handle Bar Apparatus design was put forth to help eliminate the hard mechanical looks of the original design. A center pad was designed into the bars as a chest pad in case a users arms became too tired to support themselves when exercising. Concept Three Concept 3 uses a pivoting Working Surface to provide the necessary contour for exercising. The pivoting nature allows the user to easily adjust the degree of difficulty by means of a gas spring or an adjustable rigid leg that snaps into positioning holes in the Base Frame. If the user wants to switch from the convex to the concave form, they simply rotate the form around the center pivot so the opposite side faces up.

This concept suggests that the Working surface could be molded from one piece, but the stacked aesthetic also lends itself well to construction from flat stock, simplifying prototyping and reducing production costs. It also allows the hiding of the mounting points for the Base Frame and adjusting legs within the form. The Handle Apparatus in this concept makes use off-the-shelf handle and Aero bars to give the user a more bicycle-like feeling. It also much less expensive to use off-the-shelf curved handles than custom bent tube when dealing with lower quantities. A round vertical handle tube is used to further get away from the original rigid mechanical look. My designer colleague and I liked this concept the best out of the three because of its ease of use, smaller size, and the unique stacked look of the working surface form. Because the form could be created form flat stock it gave us a lot of material choices and aesthetic flexibility.

The client agreed that this concept had the most promise and gave the go-ahead for the engineering phase. Engineering / SolidWorks Model The actual product represented in Concept 3 had to undergo a series of changes in order to meet design, manufacturing and budget constraints.

Aesthetic items that were expensive to prototype and manufacture (i.e. Corner bumpers, curved handle bars, extrusions) had to be eliminated. The client decided that a more simple, robust Handle Bar Apparatus was needed for the increased loads seen during exercise. So, standard heavy-wall square tubing was used to fabricate the telescoping Handle Bar Apparatus. Oval tubing and a bent acrylic Aero pad were used as inexpensive accents help to soften the mechanical looking structure. Various methods of attaching/detaching the different components were proved out both physically and digitally. Through the use of a breadboard mockup, we found that we could get away with a base frame half the size as shown in the concept board.

Round handles were added to end of the Working Surface so that it could be rotated to the vertical position, detached from the Base Frame, then reattached with the opposite side facing up. Because the Working Surface now had handles and was much smaller than the original design, this procedure could be done with little effort. Once we felt that the engineering phase was complete, a detailed drawing and BOM package was compiled.

These packages went to different manufacturers to get production quotes. Precis Velo Alpha Prototype The alpha prototype was built with parts both fabricated in-house and with outsourced components.

Transparent blue acrylic was laser cut and bolted together with machined acrylic spacers to create the working surface. All steel and plastic parts were machined by manual mill and lathe if possible and otherwise outsourced for CNC cutting. Welding was performed with both MIG and TIG welding processes.

Two complete systems as shown above were delivered to the client. With the delivery of the alpha prototype the client also received a complete engineering release package containing native SolidWorks solid and drawing files, a detailed BOM, as well as purchased and fabricated part quotes. Folded Position The Pro/E assembly model was created with moveable mechanical joint constraints so that it could be rotated through is entire range of motion. Any interferences during the folding process could be found and corrected in the engineering phase before any prototype parts were fabricated. One particular challenge was to design the unit for efficient shipping box size. The client calculated what size box the unit had to fit into in order to efficiently fill a shipping container and obviously the stroller has to fit within this space.

In order to balance this collapsed size with an ergonomically correct usage height, the front casters, uprights, and footrest were designed as a separate subassembly that was snapped on by the consumer after opening the package. Another challenging addition is the introduction of all the soft goods (seat fabric, foam, covers, etc.) that cannot be modeled accurately in the computer during the preliminary design.

Exploded View of Ellipsa Stroller The Ellipsa stroller is a very complex articulating assembly using many different parts made from many different materials and processes. Casters were made from injection molded yokes with expanded foam tires and had internal rubber bushing to act as suspension.

The frame was constructed from oval and round bent and welded tubing and formed sheet metal. Press fit snap features and crush ribs were designed into plastic tube ends that were to be permanently mated to the metal structure.

A vacuum-formed tray liner can be removed from the tray and disposed of when it is too dirty. Main Pivot Lock Mechanism One interesting area of design in the Ellipsa stroller is the Main Pivot Joint. This is the joint that locks the stroller in its open position once it is unfolded. The Locking Lever shown in orange keeps the gray Rotating Arm from moving by nesting itself into the notch. To collapse the stroller, the user pulls a pistol grip lever at the top of the handlebar assembly.

This lever pulls cables that extend down the handle bar tubes and connect to cylindrical Cable Ends that slides freely within the tube. The Cable End interfaces with the Locking Lever with a pin and slot connection. When the cable is pulled, the Cable End is pulled upward through the tube and in turn rotates the Locking Lever out of the notch. The rotating arm is then free to pivot. Support Ribs were designed into the Joint Housing to help distribute the forces from the Locking Lever. The J-flex cart is an industrial cleaning product made by Johnson Diversey, a division of Johnson & Johnson.

The cart is sold as a vehicle for Johnson Diversey cleaning chemicals which is the company's main technology. The cart's yellow body is a one-piece rotationally molded plastic part. Two blow-molded plastic support legs dovetail in from the rear and are fastened by screws.

A retractable hose and coiled sprayer system make attaching the cart to a water supply and washing down equipment a snap. Provisions are made for a mop bucket, broom, trash bin, as well as for proprietary Johnson Diversey chemical spray containers. The molding process is inherently water-tight and pockets are designed with drain holes, so even washing down the cart itself is easy.

J-Flex Pro/Engineer Assembly The surface model for the roto-molding pattern started with three orthographic views from the Brooks Stevens design staff and a breadboard mockup for reference. The mockup was used to debug the coiled hose pocket, chemical bin sizes, retractable hose clearances and for general ergonomic concerns. Modeling for roto-molded parts is easier than for injection molded parts because internal geometry is not important for tooling. The model can be left as a solid and need not be shelled or internally ribbed. Base Detail One engineering challenge behind the Streamline pole was to make a stable base in the deployed position, but also to decrease it's size when it was to be attached to an ICU bed.

The solution was to use a 4-bar linkage mechanism to collapse the legs, much like what is found in an umbrella or music stand. This mechanism was actuated by an internal gas spring. So, once the pole was secured to the bed, the red foot pad was depressed which in-turn released the spring and retracted the legs. To redeploy the legs, the user simply stepped down on the stainless foot pad until the legs locked back into their original position.

Design Of Post Tensioned Slabs On Ground 3rd Edition Manual Muscle Cars

IV Pole Mounting System The second part of system involves mounting the IV pole onto the bed or wheelchair. The simplest solution would normally be to bolt a rigid mount to the bed and then secure the pole to the mount. However, in practice the location of the pole as the bed is traveling in the hospital is of great importance. In many cases staff has to navigate around other beds or into tight quarters such as elevators, so the ability to move the mounted pole around the bed is essential. I traveled to a local hospital and measured a typical bed in order to build a mockup and test these situations in the shop.

The solution was to use a pivoting and telescoping arm mounted to the end of the ICU bed. The arm can be swiveled 180 degrees and an internal flat spring returns the telescoping arm into five different nesting positions around the perimeter of the bed. Analogic Corporation's core technology is CAT scanning equipment. They develop both medical and security scanning products. The COBRA system is Analogic's recent effort under contract of the Department of Homeland Security.

The COBRA is a baggage scanning system that measures the different densities of every item in a piece of luggage. It then converts the density measurements into solid models. If the density of the item is suspect (ie. C4 explosive) that item can be digitally plucked from the suitcase as rotated around in 3D space without ever having to open the bag. Brooks Stevens Design was contracted with designing and prototyping the outer skin and user workstation for the COBRA system. Industrial Design and Engineering staff brainstormed various features and styles and eventually came up with the design shown in the article above.

The COBRA skin model was initially built in Alias for the concept presentation. Typically, this surface model would be totally rebuilt in Pro/Engineer. But, due to time constraints, the Alias model had to be brought into Pro/Engineer directly as the project entered the engineering phase.

As a Design Engineer I was responsible for taking over the Alias model and turning it into a reality. COBRA Pro/Engineer Assembly To access the complicated internals of the COBRA system the outer skin had to be intelligently divided up in multiple panels made from fire-rated fiberglass composite. There were many different engineering challenges to tackle.

For air flow and cooling issues each panel had to seal against the next, so all panel had to have a series of overlapping joints to hold gasketing material. Also, internal bracketry had to be designed to connect each panel to the underlying sheet metal lattice structure. This structure was not always square, so adjustment features had to be designed into the bracketing system to make it look correct in the field. Certain panels were designed to be quickly removed and replaced in case a bag jammed up the system. Other panels had to be designed with key locking features or sheet metal filter housings or electronics. Each of the panels shown above was used to create a fiberglass tool models for in-house prototyping. Molds were CNC machined from Ren Shape blocks and hand laid-up with fiberglass composite.

The height-adjustable user's workstation was necessary to accommodate all different sizes of TSA employees. An electronic actuator with push-button controls powers the unit up and down.

The workstation is fabricated from formed and welded stainless sheet and uses an internal bearing block and rail system for smooth operation. The workstation provides two 20” flat screen monitors, keyed system lockouts, an emergency stop, and a writing surface. Beta Prototype Field Testing After the alpha prototype was shown at a security convention in Chicago, we plunged into Beta prototyping efforts.

Major adjustments were made to the tunnel opening size and to the bag jam access doors. The Pro/E model was updated and new fiberglass tools were cut and sent to a professional fiberglass productions house. I spent a number of weeks helping to trim finished panels and fit them to a prototype framework that we built on the production house floor. After all the panels were painted, finished, and fit, they were shipped off for Beta testing. The above photo shows the unit undergoing testing at Logan International Airport in Boston. Rail System: Location of Highest Load As with the sling assembly, the rail system also had to be analyzed for agreement with code.

The code states that the static stresses in rails system and all of its components must stay below 15 ksi and have less than a quarter-inch of deflection when the sling is in a position to create maximum load on the rails. It also requires that during Emergency Braking (say, if the cable snaps and brakes engage) all stresses in the system must be below 27.5 ksi. The first part of this problem was to find out exactly where on the rail system the sling had to be positioned in order to create the maximum stress. The sling moves along the rails much like a train or roller coaster moves on its track. The maximum stress in the rail depends on where the rollers on the sling are positioned relative to the wall supports along the rail. A spreadsheet was set up using continuous beam theory in order to plot the maximum stress in the rail versus the location of the sling rollers. As it turns out, that the maximum stress occurs when the rollers straddle the wall mounts.

Now this positioning was known, it can be used for all the following calculations and simulations for maximum stress and deflection. Dynamic Drop Testing The second part of the problem was to figure out the dynamic load put on the system as the elevator cab drops and the safety brakes engage. The rate of this acceleration has an enormous effect on the stress levels in the system, so an accurate measurement of this figure is needed. If we knew the elevator cab weight, how far the cab dropped when the cable were cut, and how long it took the cab to stop once the brakes engages, then we can calculate the average acceleration on the cab using kinematic equations. So, we designed a series of drop tests and measured the total distance the cab dropped, as well as the “skid mark” that the knurled braking rollers left on the rail as they slow the cab.

Now, we had all the information we needed to calculate the additional force put on the system during emergency braking and this value could be used in the following FEA simulations and hand calculations. Wall Bracket Pullout Stress As the safety brakes engage, the elevator sling rollers produces a large moment on the supporting rails. At the top of the sling, this moment causes the rollers try to pull the rails and wall brackets away from the wall, and at the bottom it pushes them into the wall. The brackets were designed well to be loaded with additional support from the wall, but lacked strength when being pulled away. The above image shows the pulling stress plot. In this situation it was found that the brackets contained stress in excess of the code. To bring this bracket into agreement, a supporting gusset had to be designed that could be installed easily in the field.

Safety Block Stress Plot ASME A17.1 states that the stresses in the safety components must have a Factor of Safety of at least 3.5. The mechanism works by using a wedge-shaped steel block, a knurled roller attached to a sprung armature, and the support rail that the elevator rides along. If the lift chains lose tension, the armature drives the knurled roller into the wedge created by the safety block and the guide rail. As the weight of the elevator cab drives the safety block downward, the knurled roller wedges itself tighter and tighter and quickly stops the cab from falling. The above stress plot shows a simulation of this situation. It seems worrying at a first glance, but the areas above the limit in red can be explained. The loading situation between the braking roller and the safety block is a line-on-surface contact situation and will always cause a stress riser in the plot.

The other areas of concern are located around the bolt holes, but since these holes were used as fixture constraints, high stresses in the plot are expected. Because the sections of red are concentrated to small areas of expected high-stress, the design was deemed to fit within the limits of the code. SolidWorks Surface Model AXN RXN started by dropping the designer's orthographic views into SolidWorks so I can be sure that the final surface files will match the original design intent. The above picture shows the three orthographic views and a few of my initial setup curves. Modeling continues in this manner and build a complete wireframe of the product. Then, patching in surfaces from the wireframe curves arrives at the final model.

Because all of the curves are based off of the designer’s sketches, any adjustment they want to make to these sketches can be quickly updated through the model.