Designing a Hydraulic Parking System to Help Alleviate the Problem of Parking in Urban Areas - Term Paper Example

Your Full Name: ------ Professor’s Name: ---- Subject: Hydraulic parking system Date: 13th January, 2013 Hydraulic parking system Introduction The world population is moving towards urban areas increasing pressure on the space for occupation. This has led to the design and construction of buildings that are storey to accommodate offices and for residential. This people have extra income that will support comfortable life such as owning a car. This cars can not be parked anywhere thus we need a well designed car park system that can hold many cars economically. This paper is theoretically designing a hydraulic parking system to help alleviate the problem of parking in urban areas. Today there are a number of car park systems made but newer technology is to be used to accommodate the ever increasing demand for parking space. Here a Hydraulic parking system is being designed to solve this issue successfully. Hydraulic parking system has been used for some years and as a result is not considered new inventions by any means. This parking system is beneficial to car dealers’ manufacturers and offices as well homes. Many The proposed hydraulic parking system will be as shown below Figure 1: (Focus Technology Co., Ltd) However, it has become necessary for it to become easier and safer to use due to their monumental scale. Hydraulic parking system is popular because they are accommodating multiple numbers of cars within a small confined space. We are all well aware of the complexity, danger and time it takes to design such structures and also aware of the historical importance of these structures but we are often unaware of the technology employed to create these structures. Here we will highlight the workings of hydraulic parking system starting from literature review on various systems, their operation, components, and the materials used as well as showing how the designs are selected Conceptual Design Stage Design Requirements- the design of hydraulic parking various parameters needs to be considered and they include; Dimensions – maximum length, width and height Weight – maximum includes average human and car weight Mechanisms for transportation Safety Levels The main factor which is extremely important is safety. This is because it involves human contact and if not given importance could be very risky. The second factor to be considered is the mechanism being used to transport the vehicle from one place to another. This is also important because it will determine how compact the space is, how easily it is operated etc. In the design of the system the dimensions of the car park is significant thus the diagram below shows an average dimension layout of the proposed parking system for car: Figure 2: Sketch of hydraulic parking system Design Alternatives To design a good parking system various sections of design will discussed and they include parking system framework, Lifting Method, Power Drive and speed recommended. Framework – this is how the parking system will look like when complete and in use. Frame Designs- Figure 3 Frame 1 This is another design for a frame where the car is supported on a plate which resembles a cantilever beam. For the upper plate to come down, the lower portion should be free from any sort of vehicle which turns out to be a disadvantage as well. Moreover, this type of support experiences a lot of stresses due to the load on top causing deflection and over a long period of time could result in failure if not made from a strong tough material. This looks like this when complete; Figure 4: Side view of the hydraulic parking system The structure that will carry one car is shown below; Figure 5: Sketch of parking system with dimensions of cars The following diagram shows the frame design that enables the parking of cars to be controlled. The mass of the car will be evenly distributed because the structures are well designed. Figure 6 Frame 1 The cars are parked underneath the structure. The following structure shows a system hat is complicated but is also save and can hold the two tiers of cars Figure 7 Frame 2 This type of system is good for show rooms and places where safety of the public can be comprised. It has a support at centre helping to reduce stresses experienced when carrying the load. Lifting Method Designs This defines how car will lifted to the tier in the parking system. There are various designs selected to be considered for the system and they include; Figure 8 Ferris wheel lifting method It has a circular wheel that has a belt to lift the car up when rotating and down when rotating to the opposed direction. This system will require a large space beating the logic of tier parking system and it is costly. The following design will also be considered in our design; Figure 9 Swing locking system This system uses plating system to lift up vehicles where a car is placed on a plate and it is lifted up to the next tier then to its parking place.. it require materials of high shear strength as well a locking system. This makes it costly to manufacture and install. The next is another design call swing system; Figure 10 Simple swing systems As the name suggests its motions are swing like and it is less costly. Power Drive Designs This defines the source of energy and t is distributed within the system to make the hydraulic parking system operate. The following are designs available for the system to operate. The first design is Electric System Figure 11: Electric System This power supply distribution is common in industries because it carrying large loads and it may not be best situated for the parking system. It has a motor and the pulley system and still be powered by fuel hydraulics instead of pulley blocks. The rate of movement is to be controlled by hand with the help of now extraneous booms or electronic slew rate monitors and controls. The slew rate has to be calculated in a number of ways as wind, vibration and weight all contribute to the slew rate. The lifting jib can also be moved horizontally to work in confined spaces without having to dismantle the plate. It is expensive to manufacture, install and maintain. The other system of power supply that can be adopted is Pneumatic System which is shown below; Figure 1 Pneumatic System The system proposed above is in use in many engineering section however, the cost of manufacture and maintenance is inhibitive. It requires large space to be effective and efficient. The next power drive system under consideration is Engine and gearbox system Figure 2 Engine and gearbox system This option is one of the best in terms of maintenance, purchase, installation and usage. It is uses small space and provides effective movement and good performance compared to the other designs. The best advantage this design provides is that it has a variable speed control with the help of the gear. Motion Designs This is type of movement that will be selected to enable movement. The first case is the pulley system as shown below; Figure 14 Pulley System The pulley system is the first designs related to motion which uses a cable being looped between pulleys that can are operated in the opposite directions. The mechanism is situated at centre while the other also rotates to make it work. The operation is controlled and moderated by adjusting the cable with the pulleys at ‘A’ ‘B’ and ‘C’ . What must be stated here is the level of accuracy necessary in order to achieve this, due to the dowels and holes created in the drums having to match identically to each other. If the cable is strong enough the pulley system is very reasonable in terms of price, construction and operation. Its maintenance cost is less as well due to the inexpensive spare parts. The other type is Gear System which is costly to maintain but cheap to acquire. It is shown below Figure 3 Gear System The gear system can be fault if tooth is broken in any of the wheels. The other system is the piston system as shown below; Figure 4 Piston Cylinder This system is gas operated making it costly and complicated Selection Criteria In selecting which option s to use various factors are considered which include cost-benefit analysis, budget, High Reliability, Large Life span and High Safety The table below clearly states its importance in terms of percentage as shown below: Table 1 Criteria Vs Weight Table Criteria Weight / % 10 20 30 40 Budget – 20% Cost –benefit analysis 15 % High Reliability – 20% Large Life Span – 15% High Safety – 25% Design Evaluation The various design options are as follows: Design 1 Figure 5 Design A This design uses the triangular frame type, with the swing lifting method, electric system along with pulley for the power drive and motion. Design 2 Figure 6 Design B This design uses the one car on top of each other and supported from the middle frame design, along with the Ferris wheel lifting method, pneumatic system and gears for the power drive and motion system. Design 3 Figure 7 Design C This design uses the cantilever support beam frame along with swing locking system lifting method, engine and gear system along with a piston cylinder for the power drive and motion system Evaluation There are a number of values which can be selected ranging from either 1 to 5 or 1 to 10. For this project, the evaluation range taken s 1 to 5 which is represented as shown below: Table 2 Value and representation Value Representation 1 Very Poor 2 Poor 3 Average 4 Good 5 Very Good Table 3: Design Evaluation Criteria Designs Design 1 Design 2 Design 3 Value W.V Value W.V Value W.V Budget – 20% 3 60 2 20 3 60 Cost –benefit analysis – 20 % 2 40 4 80 2 40 High Reliability – 20% 3 60 2 40 2 40 Large Life Span – 15% 3 45 3 45 2 30 High Safety – 25% 4 100 2 50 2 50 Total Weighted Value 305 235 220 Design 1 is given priority because it has the highest score. Morphological Chart The following Morphological Chart is used in the selection of the designs to made is done. The arrows shows the selected options; Table 4 Morphological chart Sub-Function Function Solution Frame/ Structure Lifting Method Power Drive Motion Chosen Design It is necessary to choose the fastest, safest and more reliable system. When looking at the differences between the options, the pulleys with fuel or electrical hydraulics, but the main areas of real innovation have been our understanding of safety. The use of such parks comes with its own set of precautions, as the weight and height of the loads are far greater today than they were in ancient times. Design Operation- The movement resembles a rack and pinion system where the triangular members move in order to place the car in or outside the frame. The car comes on the upper flat bed of the triangle and will move alongside till it returns to the ground. Figure 8 Frame operation line In order to withstand the weight of the car, a supporter is attached helping to strengthen the plate as well performing the operation more safely. The plate is further attached via a chain or a cable which will help the car descend or ascend smoothly. This cable is connected to the motor selected along with the pulley system helping to allow easy movement of the system as a whole. Step by step component elaboration Table 5 Component Elaboration Component Elaboration This safe framework for the system as well as it is efficient in its operation. This aerodynamic shape is good for those functions.. This is safe for both the owner and the car. This lifting system is also simpler and less costly to construct. It has an advantage of occupying small space. The cost of maintenance is low as well requires less activities in terms of repair. This makes it the best in providing power drive for the system as compared to other option. Sometimes some systems are expensive and some are not yet both get the job done properly. The pulley system is the same kind performing its purpose in a simple and cost effective way. It also provides the option of being able to change in either a clockwise direction or an anti-clockwise direction. Primary Sub system Flowchart The following is a flowchart for the car parking system. A flowchart is important in getting an overall view of the car park system and the various components it is comprised of as shown below where the dotted line represent connection between the components: Figure 21 Primary sub-system flowcharts Auxiliary System- some of the car parks components include Roller Shafts, Bolts used for fixing, Rollers, Bottom rubbers along with inner springs. Detailed Design Stage Designing is very important in park system as it allows components to assembled using proper dimensions. It will be designed in a manner that will take a shorter time to park a car safely. This is a multi-task activity because, the parking system will not only required to carry out one activity but many. However in order for cars to be parked easily, the system capability and characteristics of the materials plays. In designing the parking system three variables are involved weight, material straight and speed. Structure- There are completely four components the entire structure is divided into as shown below which are further described separately and they are Support frame, Top plate, Triangle support beams, Rollers and Rubber stand for scratch prevention Top Plate- This plate is the part where the car is parked during entrance and exit into the system. It is decided by the team to manufacture this by steel having it bolted to a steel frame as shown below: Figure 9 Top Plate Weight Calculations- It is important to know entire weight of this plate and its corresponding components. Thus, with the help of standard steel property tables available widely from various sources is used. Figure 10 Top Plate Top View As shown from the figure above, the plate is split into half due to symmetry and categorized into three individual components shown by the colour codes. The calculation will be done for each beam separately and then multiplied by a factor of 2 due to the symmetry mentioned earlier. Assumptions are always necessary to conduct many calculations and so the first assumption and type of beam being used is a 20 by 20 cm beam which has a mass of 84kg/m and the following cross section and table of values: Table 6 Dimensions Size Thickness Comer Radii Mass/m Area of Section Second moment of Area Radius of Gyration Section Modulus Plastic Modulus Torsional Constants Section Surface Area Ext1 Int1 Inertia Modulus B T M/m A I r Z S J C As mmxmm mm mm mm Kg/m cm2 cm4 cm cm3 cm3 cm4 cm3 m2/m 400 14 48 32 84 107 5625 7.26 562 706 10210 901 0.718 Another assumption required to calculate the total weight of the plate is the thickness which is assumed as 1.5cm. This number was chosen in order to be thick enough to withstand load from the cars weight. The calculation is done by decomposing the structure into separate parts shown below: Figure 11: Frame Top View Rollers Beam This acts like a rolling tray for the top plate to move it from top to bottom and back. It comes with wheels below and is welded to the upper beam. The same way the first component was analyzed with separate beams, this component is also analyzed similarly shown below: Figure 12 Rollers Beam This beam is a 10 by 10 cm steel beam having the table of values below: Table 7 Rollers Beam Dimensions Size Thickness Comer Radii Mass/m Area of Section Second moment of Area Radius of Gyration Section Modulus Plastic Modulus Torsional Constants Section Surface Area Ext1 Int1 Inertia Modulus B T M/m A I r Z S J C As mm x mm mm mm mm Kg/m cm2 cm4 cm cm3 cm3 cm4 cm3 m2/m 100 8 20 12 24 27.2 366 3.67 73.2 91.1 645 114 0.366 Triangle support beams These beams are used to support the top plate and frame together increasing the strength. These are pinned together to the structure supporting it from all sides. Figure 13 Triangle Support Beams Each beam is separated and has a C shape cross section with the following dimensions as shown: Beam 1: Beam 2: Beam 3: Support Frame Similar as to the first procedure, the support frame is also calculated component by component. The beams used her are both 20 cm by 20 cm and 10 cm by 10 cm. from previous calculation, it can be clearly said that 20 by 20 beams have a weight of 84 kg/m and 10 by 10 beams have a weight of 24 kg/m Figure 14 Support Frame Front view Figure 15 Side View - 20 by 20 beam Dimensioning The following dimensions were achieved using AutoCAD: Figure 16 Support Beams Dimensions Applying Pythagoras theorem the following information is calculated: Table 8 Triangle Beam Dimensions Length/cm AB 200 AC 600 BC 632 Angle/degrees BAC 90 ABC 68 BCA 22 Figure 17 structure Sliding Path Figure 18 Sliding Path Since the car is first placed on top and then this plate comes sliding down to allow it to exit or vice versa in the condition of parking inside the car park system, it is necessary to analyze this path to avoid any mistakes as well as to maintain high standards of safety. As shown by the figure, there are two paths, one is called the bow path and one is the straight path. Bow path has a curvature as shown and is the link from top to bottom. The straight path is a simple inclined line like the side of a triangle which covers the remaining motion Bow Path Calculations The shape of path looks like a bow thus the need to analyse first quarter of a circle which is critical because of the curvature which can make the car unstable by changing the centre of gravity suddenly causing the car to tip over. This angle is then maintained by the inclined length. The first quarter of a circle is considered because the shape resembles that of the bow path. This is then further divided into 60 degrees and 30 degrees in order to resemble the exact shape and decrease the inclination. This further reduces the stress concentration in this area giving a much safer pathway. Figure 19 Bow Path Calculations for 60 degrees circle section Straight Path Calculations This is the easy bit because now that the bow path is decided, all that needs to be done is to extend that line directly to the base giving a straight inclined line as shown below: Figure 20 Straight Path Dimensions Total length required calculations The length that is referred over here is the total distance required when the top plate has descent down completely as shown below giving a total value of 1282 cm. Figure 21 Total Length Dimensions Movement calculations It is important to know how slow or how fast the plate should move from left to right or vice versa. The team has decided that the time taken for the plate to reach the beginning of the bow path should last 1 minute i.e. 60 seconds in order to maintain high safety factors. Once it reaches this path, the descending motion should approximately move at a speed of 0.095 m/s giving us a calculated time of 25.5 seconds. Figure 22 Plate Movement Structural Analysis It is extremely important to conduct a structural analysis on every design where safety is a huge factor needed to be considered because it helps to identify the stress points and how to make it stronger in order to withstand the load. The solution usually ends up by increasing the dimension or by using another material. The frame will be tested as shown below: Figure 23 Frame section The load applied was 6950 kg including the car and platform and the material selected was 1018 mild steel which has a relatively high tensile strength of approximately 500 MPa. The load was divided into 4 individual forces being applied onto the structure as shown below: Figure 24 Four individual loads applied on frame Figure 25 Analysis conducted As shown from the above figure, higher stressed points are the joint as well as the bow shape path. However, the stress is at an acceptable level because it is part of the blue region rather than red. The safety factor calculated is: Figure 26: Bow Path Stress analysis Figure 27 Connection Stresses Stress Calculations This is very important in ensuring material used are not strained beyond capacity. We begin with bolts and pins helping to attach the various components together. The triangular beam supports are fixed onto the frame hence not exhibiting and shear stresses when the car is stationary. However, once movement begins shear stress is present in the structure because it resists the entire weight of the car from the beginning till it descends completely. Bolt Calculations To decrease this stress, it is advised to use a bolt to distribute the stresses. To know which bolt would be most reasonable for this application, certain calculations are needed as shown below: A specification sheet card is available as shown below from which the bolt will be selected. For this case for safety reasons M10 is chosen which has an allowable load of 429kgf. Figure 28 Specification Sheet Card Pin Calculations The car’s back side consists of a movable pin which allows the movement of the car. The diameter of this pin is necessary and is calculated as follows: Where F = 17,375 N and  = 275 MPa Sizing and Selection Frame Mild steel was selected for the frame and consists of a small percentage of carbon ranging from 0.15 to 0.30 and has a density of 7870 kg/m3. The tensile strength has a maximum value of 500 MPa and a young’s modulus of 210,000 MPa. The table below show the final dimensions without considering frame thickness: Table 9 Final Dimensions Car dimensions /cm Regular dimensions for frame/cm Selected dimensions for frame/cm Reasons for selection Height – 170 Height – 170 ~ 220 Height – 200 Suitable for a person standing in the lower deck Width – 190 Width – 260 ~ 300 Width – 280 Average taken as per car dimensions and clearance space Length – 520 Length – 520 ~ 600 Length – 580 Average taken as per car dimensions and clearance space Rack and Pinion This system is designed to convert rotational motion into linear motion by engaging the teeth found on the pinion onto the linear rack. Image of rack n pinion on structure and rack n pinion itself. There are a number of options available for the rack as shown below: Table 10 Rack Types Rack Type: Tooth Quality: Tooth Hardness: Tooth Pitches: Segment Lengths: Typical Applications: Soft Rack AGMA 9 (DIN 9) ~28 Rc Module 1.0 to 10.0 Up to 3.0 Meters Light Loads Medium Accuracy Quenched & Tempered Rack AGMA 10 (DIN 8) ~28 Rc Module 2.0 to 5.0 Up to 2.0 Meter Medium Loads Medium Accuracy Induction Hardened Rack AGMA 8 (DIN 10) 50 - 55 Rc Module 2.0 to 10.0 Up to 2.0 Meters Heavy Loads Low Accuracy Hardened & Ground Rack AGMA 12 (DIN 6) 60 Rc Module 2.0 to 10.0 Up to 2.0 Meters Heavy Loads High Accuracy The green box indicates the selection made which is usually recommended by most engineers. Further calculations to determine the size are as follows: Using the data sheet below, the helical module 5 was chosen: Pulley and Cable system This system is where the winch system is being operated along with a cable helping to change the direction of motion which in turn changes the force direction. A total of four pulleys are being used. The first connection is between the cable and the winch system extending it around the pulleys 1, 2 and 3 and then locked into the hook placed on the platform. When the motor is switched on and movement is in the anti-clockwise direction, the cable is pulled towards the platform allowing it to move forward with the help of the rack and pinion motor until it reaches its maximum length putting the motor to a complete stop. The winch motor then starts with the opposite clockwise direction changing the link of the cable from pulley 4 to pulley 3 allowing the plate to move downwards to the bottom floor. Cable Sizing In order to select the appropriate cable, it is important to analyze the breaking limit of the rope to measure its strength. Hence, the team has decided to go with the stainless steel cable numbers 6X37 Class which provides extra flexibility and corrosion resistant properties. Moreover, the larger the number of wires used, the more the flexibility leading to lower resistance to pressure and abrasion. Even though this cable is a bit expensive compared to others found in the market, it is found to be the most suitable and safest material one can use. This is very important because failure of this cable could lead to catastrophic events. The green box shows the selected kind because it provides a 15,800 lb break strength which is way above the calculated value leading to a safer operation. Figure 30 Breaking Limit for the cable Pulley Sizing A pulley system is a circular wheel consisting of a single groove between two flanges found around the circumference. For our case, a cable is placed inside this groove allowing to change the direction of the force being applied either rotational or linear movement. The pulleys being used are of the same diameter which gives the advantage of maintaining the same force while the direction changes. An example is taken to understand the system even better by taking a 45 kg mass suspended from a rope as shown in the figure below. It is quite evident that the weight doesn’t change only the direction of the force changes. Hence the team has taken the same approace. Figure 31 Pulley system[Mar11] The rope selected by the team has a diameter of 0.011m and the pulley selected has a diameter of 0.0127m which is the V-idler ½ inch category shown below: Figure 32 Pulley selection Rollers This component helps to distribute the entire weight of the top plate as well as move the plate from the beginning till the end of the rail. The force that is distributed evenly is of 65000N and the best suitable roller to withstand this force is cam rollers. These are widely used for heavy load tracks and come with an attached shaft helping to reduce fatigue. Figure 33 Cam Rollers[SKF13] Under cam rollers, the SKF specification was used which gives a diameter of 52 mm and a total width with shaft is 66 mm which helps to hold a maximum radial load of 36KN. Figure 34 Cam Rollers dimensions The number of rollers to be used is 8 with 4 on each side of the frame. However, the load on each roller is as follows: Rubber stand This is placed underneath the triangular beam support helping to protect the frame from scratches increasing its durability and reducing maintenance activities. The diameter for these rubber stands is 8cm with a thickness of 1cm and is widely available in many shops all around. Motor Selection There are two motors that need to be chosen for different applications. One of them is for winch system and the other is the rack and pinion system. The rack and pinion system uses the same motors as the chain system. Hence, calculations for the winch system are done in the following section. Winch system This system further more uses two motors which has the force calculated divided into two equal forces From these values, the best suited motor fit for the above criteria is the Baldor AC brake motor which helps facilitate quick stops and positive hold. The motor provides manual release option with an automatic reset button and can be used when the power is off as well. Figure 35: Baldor AC Brake Motor[BAL13] Works Cited Atlanta Drive Systems. Gear Racks. Jan. 2013. 12 Jan. 2013. Atlanta Drive Systems. Rack and Pinion Drive – Calculation and Selection. Jan. 2013. 12 Jan. 2013.< http://www.atlantadrives.com/pdf/ads_racksel.pdf> BALDOR. (2013). VEBM3615T. Jan. 2013. 12 Jan. 2013. Focus Technology Co., Ltd. “Hydraulic Parking System”. Made-in-china. Jan. 2013. 12 Jan. 2013.< http://www.made-in-china.com/showroom/cn220055334/product-detailRqhJHcLXhBWA/China-Hydraulic-Parking-System.html> JAYDEE Enterprise. PULLEYS & IDLERS. Jan. 2013. 12 Jan. 2013. Klaus Multiparking Inc. Hydraulic Parking Systems Are the Most Efficient Parking Systems. March. 2012. 12 Jan. 2013. Marshall Brain. How a Block and Tackle Works. Jun. 2011. 12 Jan. 2013. Portland Bolt. (2012). Steel Plate Weight Calculator. Sept. 2012. 12 Jan. 2013. Saltire. Geometry Applet. Jan. 2013. 12 Jan. 2013 SKF. Cam rollers. Jan. 2013. 12 Jan. 2013 Sumitomo. Cyclo® 6000. Jan. 2013. 12 Jan. 2013 TEMCo. (2013). Baldor VEBM3615T-5D AC Electric Motor M14071 - 3 Phase, 5 HP, 184TC Frame, TEFC, 1800 RPM, 575 Volts, 60 Hz, D-Series Brake Motor. Jan. 2013. 12 Jan. 2013 thomasnet.com. Rollers and Cam Followers offer alternative to metal rollers. May 2004. 12 Jan. 2013 ugly easton. out with the old... well, you know the rest. May. 2010. 12 Jan. 2013 Wolfautomation. High Torque Density Speed Reducers and Gearmotors. March. 2012. 12 Jan. 2013. Appendix A – AutoCAD Drawings Read More