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"Bir kişinin bir olayı değerlendirmesi, bu değerlendirmeye esas olan bilgiden daha iyi olamaz. Ona gerçeği verdiğinizde doğru karara varma şansı olsa bile yanlış yapabilir. Ancak ona bilgi vermez, yanlış, saptırılmış veya yetersiz bilgiyi taraflı, mesuliyetsiz yayıncılık ahlakı ile veya bilerek hatalı verirseniz o insanın tüm değer yargılarını alt üst eder onu insandan daha alt seviyelere indirirsiniz. " |
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Arthur Hays
Sulzberger
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Cam Mechanisms
Cam is a higher kinematic pair which is used to transmit motion from one link to another. In everyday usage, as in the case of gear terminology, a cam is a rigid body with a curved surface that is in contact with another rigid body (usually the second rigid body is of simple shape such as a flat face or a cylinder)
A Cam Mechanism is a mechanism that contains at least one cam pair in its kinematic structure.
Cam mechanisms are one of the most widely used mechanisms because they can realize different motion curves and are simple to design. However, cams are expensive to manufacture and due to the contact stresses, they wear out easily in comparison to mechanisms that contain lower kinematic pairs such as revolute joints. Also at high speeds and/or under heavy loads dynamic effects become very critical and kinematic design is not sufficient for the proper functioning of the cam mechanism. The main reason for the use of cam mechanisms is that they provide simple means of obtaining unusual, irregular motions that would be difficult, if not impossible, to obtain with the other types of mechanisms. Cams may be made adjustable, or they may be easily replaced (as in the case of modern sewing machines) or their timing can easily be changed. These factors add to the versatility of cams. However, during the design of a machine, one should try to avoid cams, especially if high speeds and high torques are being transmitted.
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