application Object Models.
IV SCREWJACK DESIGN – MANUAL
The documentation and design procedures [1, 3] are as follows, The load
When the screw is under compression. From this relation find design of screw jack spindle parameter. Check for principle stresses, The mean diameter of screw,
Assuming coefficient of friction between screw and nut, μ= tanφ ∴Torque required to rotate the screw in the nut,
Compressive stress due to axial load,
Shear stress due to the torque,
Maximum principal stress (tensile or compressive),
The maximum shear stress, Design for nut, the bearing pressure
The shear stress in the screw, The tearing strength of nut,
The crushing of the collar of the nut,
Design for handle and cup, D3 = 1.75 d0 The pressure conditions,
The critical load,
Design of body, Diameter of the body at the top=1.5D2, Thickness of the body = 0.25 d0 , Inside diameter at the bottom,=2.25 D2, Outer diameter at the bottom=1.75, Thickness of base =2 t1,, Height of the body = Max. lift + Height of nut + 100 mm extra, Efficiency,
V. DESIGN OF SCREW JACK – OPTIMIZATION
Today’s computer is a vital role in all field to execute their needs. In an Engineering field the computer is utilized to perform and fetch data’s of an experiment. The design having number of software’s to produce a model or draft, but the model are not firm to the user initially. The user could follow the commands and procedure to produce their model and also need many days and hours to execute the model. To avoid insufficient knowledge regarding the screw jack design and long time span to design author develop a software to execute a screw jack design within a time. The software is developedusing Auto CAD embedded visual basic aide. The procedure of software development as follows
i. Link of VBA ii. Form designer iii. Modules A Design
It is “an iterative decision – making activity to produce the plans by which resources are converted, preferably, optimally, into systems or devices to meet human needs”. B Optimization
The fig .1 shows design of screw jack dialogue box and it is used to link the problem parameter. After selecting appropriate data to the each and every section of this dialogue box, click one of the command
buttons to execute. Say modelling / 2D design / parameter / view / and definition.
Figure 1: Design of Screw jack Dialogue Box.
When the modelling/ or 2D design parameter is clicked, the command in the main screen is to
execute the results of screw jack design. If any of the design criteria statement is not satisfy, then the modelling is not suitable for the design. Therefore the design is repeated with change of parameter or optimization. The execution will take the same process. The optimization is the process to run the parameter many times to fit the exact value without the knowledge of the user. Therefore the dialogue box (fig .2 and .3) shows to select the condition to link main screen or optimization dialogue box.
The Result of optimized screw jack modelling is brought out either in the form result parameter
(fig .6) or 3D modelling design of screw jack is obtained directly in the AutoCAD screen through the link of VBA command manager run mode. The view of modelling also prepared to represent the view direction to plot for the use. It is shown in fig 5.7 modelling (Fig .8) or 2D modeling (fig .9). The 3D and 2D
Figure 2: Design Condition
Figure 3: Optimization either with Load or dc Dialogue Box
Figure 4: the optimization with load
Figure 5: Optimization Either with dc.
Figure 6 : View Of Dialogue Box
Figure 7: 3D modelling of screw jack design
Figure 8 : 2D Design of Screw Jack
VI CONCLUSION
The software has been developed for a set of inputs that are being given through screw jack
dialogue box. The software gives design of modelling, drafting, result parameter, views and definition. The design of screw jack has been represented in three-dimensional view (3D) by adopting the procedure of Machine Design data. The design of dialogue box contains number of command button to interact various events of screw jack. Once set of values are given in dialogue box it produce output either in text mode or modelling in Auto CAD software. In future, the researchers or scholars are implement this kind of technic to obtain quick and precision modelling for various inputs to display number of output.
REFERENCES
[1] Dr. Sadhu singh “Machine Design” Khanna publishers, Delhi. 1997.
[2] NK. Mehta “Machine tool design and numerical control” Tata McGraw-Hill Pulishing company
Ltd., New Delhi. 1998
[3] TJ. Prabhu “Design of Transmission elements” Mani offset, Chennai. 1999
[4] Mikell P.Groover Emory W. Zimmers, Jr. “CAD/CAM Computer – Aided Design and
manufacturing” Asoke K.Ghosh prentice – Hall of India P.Ltd., New Delhi.
[5] Faculty of Mechanical Engineering PSG College of Technology “Design data” DPV Printers
Coimbatore.