Bilgisayar yardımıyla makina konstrüksiyonu ve asansör tahrik grubuna ait CAD programı
Computer aided machine construction and CAD program for elevator driving group
Yazar: CEVAT ERDEM İMRAK
Danışman: PROF. DR. HAMİT ÖZTEPE
İstanbul Teknik Üniversitesi / Fen Bilimleri Enstitüsü
Derece: Yüksek Lisans, 1992
Konu: Makine Mühendisliği = Mechanical Engineering
Dizin: Asansör = Elevator ; Bilgisayar destekli tasarım = Computer aided design ; Konstrüksiyon = Construction ; Makine konstrüksiyonu = Machine construction

Özet:
ÖZET Son yıllarda elektronik sanayindeki hızlı gelişmeler bilgisayar teknolojisini de beklenenden daha çok etkilemiştir. Kullanım kapasiteleri artan ve fiyatı da aksine düşen bu cihazlar endüstrinin hizmetine daha çok. girmiştir. ilk zamanlarda bilgisayarlar karmaşık hesapları yapması için kullanılırken bugün bu işlevinin yanında çizim ve tasarım kabiliyetleri için de kullanılır olmuştur. Bu özellikleri içeren CAD ve CAM sistemleri yaratılmış ve halen geliştirilmeye çalışılmaktadır. Ayrıca konstrüksiyonun önemli bir bölümünü oluşturan teknik resim çizimleri de artık bilgisayar programları ( AutoCAD, IBHCAD, DesignCAD gibi programları ) ile kolaylıkla elde edilmektedir. Bir hesaplama, en iyileme süreci olan konstrüksiyon, için bilgisayar ve özellikle CAD ( Bilgisayar Destekli Tasarım ) kullanımı vazgeçilmez olmuştur. îşte bu nedenlerle, yapılan çalışmada hemen hemen bütün binalarda kullanılmakta olan " Asansör Tesisi " için bir CAD programı geliştirilmeye çalışılmıştır. Klasik hesaplamanın yerine tamamen kullanıcının seçimleri ile kısa yoldan çözüme ulaşması amaçlanmıştır. Yapılan program, TURBO PASCAL 6.0 programlama dili ile yazılmış hesaplama, tasarım ve dönüşüm programı ve AutoCAD. 10 ile hazırlanmış çizim programından oluşmaktadır. Sonuç olarak bu çalışmada konstrüksiyon ilkelerinden vazgeçmeden bilgisayarın tasarım ve çizim işlemlerine uygulanması sağlanmış ve ortaya bir CAD programı çıkmıştır. -vii-

Abstract:
COMPUTER AIDED MACHINE CONSTRUCTION AND CAD PROGRAM FOR ELEVATOR DRIVING GROUP SUMMARY Industrial revolution and technological development witnessed at the beginning of this century. With the support of the electronic industry, facilitated significant improvement in computer technology, especially after the Second Wold War. Those developments in the computer technology have facilitated emerging of the new logic systems in design and manufacturing. In classical logic transformation of the idea to a product depends on experience and form, and necessitates expert personnel on its field. In this logic structure still adapted today, engineering calculation and production planning require intensive human efforts and usually cause excessive time loss and sometimes errors. Those factors, which increase the cost, prevents the idea from transformation to product in the real meaning and correctness. Computer Aided Design ( CAD ) and Manufacture ( CAM ) have been developed to create a dynamic environment in the transient period. From idea to product CAD/CAM have brought the flexibility and dynamism to the design which are missing at the classical logic application. While the computer used to be employed for carrying and the complex calculations at the beginning, today it is used for its drafting and designing capabilities as well as for those objects. CAD/CAM systems which include those properties have been tried to be developed. CAD system did not develop much at the beginning due to the lack of integral circuits and graphics screen support. Only after the 1960 's, the rate of computer utilization in design increased with support of the development in electrical industry. -viii-Nowadays the computers are known to be utilized in every phase of science, economics and industry. The modern computers have greatly developed as devices or carrying out mathematical calculations, basic logical operations and staring data. Thus the computers have became utilized in every engineering branch. They have a wide utilization capacity in mechanical engineering especially in the construction process. Because every step of the construction phase is appropriate for automation with the computer. The calculations can be actualized with a great sensitivity by means of the iteration capability. Besides, the computer does not only carry out calculation, but creates the technical drafting used in every phase of the design. Computer Aided Design and Drafting ( CADD ) is a design and drafting system created in line with this logic. The common point of classical logic and CAD logic are the technical drafting principles which are indispensable for drafting. When the development of the CAD system is studied the first example seems to be development of the numerically controlled machines at MIT ( Massachussets Institutes of Technology ) on request of the USA Armed forces in 1950 's. Actualizing Skatchpad project designs by using the same institution followed. In the second half of the I960' s, drastic developments took place by utilizing the Integral Circuits in hardware. As a result of that, the computers have decreased in size and their speed increased. CAD will be an important part of the Engineering studies in the coming years. Despite this, the knowledge about the technical drafting rules will always keep the priority. As we stated above, CAD may be considered as utilization of the computers in design activities. In the machine design to be considered, there are three basic phases; -xi-- Procedure development phase - Constructive development phase - Technology development phase Usage of the computer, is mostly encountered in the constructive development phase. This phase comprises of design, geometrical and material forming of the system and preparation of the data related to manufacture. In this process, a continuous feed-back and controlling the system in line with the requirements are necessary. We can actualize this process by writing a design program for the computer. Before, beginning to the program writing, the fields and functions to be satisfied by the program. Screen design and menu commands are determined. The drafting by computer aid is actualized by utilizing the AutaCAD.10 program. AutoCAD, which is a design and drafting program package and most widely used CAD system recently, has been developed to be used on the Personal Computers ( PC ). The Drawing Exchange File { DXP ) of the drafting produced by using AutoCAD may be taken and by making modifications on this file according to the desired design a new drafting may be obtained. The new and different draft may be obtained by changing the draft values and placing the new values on the draft. Creating an independent DXF file by writing, it manually is difficult and nessitates meticulous study, and it may be difficult also to eliminate the incompatibities between that file and the draft itself. A draft produced by a general purpose CAD system ( in this study, AutoCAD. 10 was used ), may be used in creating a different draft file which can be used on certain phases of the design by using a high level programming languages ( TURBO PASCAL 6.0 was used in this study ). -x-The procedure pursued in this study may be explained as below: Firstly a sample draft was created in AutoCAD and the DXF file of.this draft was obtained. This DXF file is utilized in creating new DXf file. Those new DXF files are transferred to new drafting by using AutoCAD, those drafts are started on the diskette and may easily be used whenever desired. Using and also creating DXF file are too difficult. Because it contains thousand of lines. Some numbers have got special meaning that must be known by programmer. In this study SCR files are used instead of DXF file. Because creating SCR file is easier than DXF file. It can be obtained by using TURBO PASCAL 6.0. AutoCAD. 10 contains SCR files. Entering external text into a drawing is only one of many uses for the Script command. Script is actually a means of saving keyboard entries that can be played back all at once. This similar batch files in DOS. As an example to the CAD application, an lifting installation which is used almost in every building was considered. Driving group of the lifting installation was determined first by carrying out the necessary calculations, and proper drafts were created later. Elevator is a means used in vertical transportation between the buildings floors. This function of the elevator is facilitated by the driving group in the engine room, guided frame and elevator cab. In this study, only the driving group of the lifting installation in the engine room was considered. The elements of this group, which are determined by the necessary calculations, are listed below: - Asynchronous motor - Elastic coupling ( with brake disc ) - Break mechanism ( block break ) - Worm gear unit - Drive disc - Rope -xi-In order to carry out the necessary design of those elements, data on construction and calculation should be given. Motor used is three-phase asynchronous motor. Due to their proper operational characteristics, these motors are preferred. The speed is in the range of 750 - 1500 rpm. Elastic coupling which is selected in order to minimize the stroke and vibration effects in the power transmission is also used as break disc. As a break mechanism, Eldro - break is utilized. Break disc, is the second disc of the elastic coupling. In the gear box, which carries out the reduction of the speed, a worm gear unit with a high convention ratio is utilized. The element actualizing the movement is the drive disc. In this system, which is driven by the rope, there are grooves on the disc. The rope is the last element. Four ropes of type SEALE are used in the lifting installations. The calculations on the elements stated above are carried out and the necessary data for the draft is obtained. That data is transferred to the draft by means of the SCR file created by our subject program and by AutoCAD. 10 later on. TURBO PASCAL 6.0 was preferred as a high level computer programming language in this study for calculation and transformation objectives. AutoCAD. 10 was also preferred for its drafting and proper vision obtaining facilities to the designer. To sum up, a pattern study was carried out on the CAD system which is widely used in the industrialized countries, but only recently discovered in our country. The considered lifting installation was also rearranged in line with the conditions of today. -xii-