Design of Equipment and Machinery Selection Series CL Specific Product Precautions 1 Be sure to read before handling. The precautions on these pages are for the fine lock cylinders and the lock-up cylinders. For general actuator precautions, refer to Actuator Precautions on pages 3 to 7. Warning Warning 1. Construct so that the human body will not come into direct contact with driven objects or the moving parts of locking cylinders. If there is a risk of contact, provide safety measures such as a cover or a system that uses sensors that will activate an emergency stop before contact is made. 2. Use a balance circuit in which lurching of the piston is taken into consideration. If the lock is applied at a desired position of a stroke and compressed air is applied to only one side of the cylinder, the piston will lurch at a high speed the moment the lock is disengaged. In such a situation, there is a risk of injury to humans, or equipment damage. To prevent the piston from lurching, use a balance circuit such as the recommended pneumatic circuit (P. 704). If an air-hydro fine lock cylinder is used, make sure to operate the lock portion through air pressure. Never use oil on the lock-up cylinder because the lock-up cylinder is a non-lube style. Failure to observe this could cause the lock to malfunction. Refer to the following criteria for the maximum load in the locked state, and set. Holding force (maximum static load) means the maximum capability of holding a static load that is not accompanied by vibration or impact under the condition that no load is applied. Therefore, it does not refer to a load that cannot be held constantly. To ensure braking force, the maximum load must be set as described below. 1. For constant static loads, such as for drop prevention: . Fine lock series (Series CLJ2/CLM2/ CLG1) 35% or less of the holding force (maximum static load) Note) For applications such as drop prevention, consider situations in which the air source is shut off, and make selections based on the holding force of the spring locked state. Do not use the pneumatic lock for drop prevention purposes. . Lock-up series (Series CL1) 50% or less of the holding force (maximum static load) 2. When kinetic energy acts upon the cylinder in a locked state, such as when effecting an intermediate stop, there are constraints in terms of the allowable kinetic energy. Therefore, refer to the allowable kinetic energy of the respective series. Furthermore, during locking, the mechanism must sustain the thrust of the cylinder itself, in addition to absorbing the kinetic energy. Therefore, even within a given allowable kinetic energy level, there is an upper limit to the amount of the load that can be sustained. . Fine lock series (Series CLJ2/CLM2/ CLG1) Maximum load at horizontal mounting: 70% or less of the holding force (Maximum static load) for spring lock Maximum load at vertical mounting: 35% or less of the holding force (Maximum static load) for spring lock . Lock-up series (Series CL1) Maximum load at horizontal mounting: 50% or less of the holding force (Maximum static load) Maximum load at vertical mounting: 25% or less of the holding force (Maximum static load) 3. In a locked state, do not apply impacts, strong vibrations or rotational forces. Do not apply a impacts, strong vibrations or rotational forces from external sources, because this could damage or shorten the life of the lock unit. 4. The locking of the fine lock cylinder is directional. Although the fine lock cylinder can be locked in both directions, be aware that its holding force is smaller in one of the directions. CLJ2/CLM2/CLG1・・・・ Holding force at piston rod extended side decreases approx. 15%. 5. The locking of the lock-up cylinder is unidirectional. Because the locking direction of the lock-up cylinder is unidirectional, select the locking direction in accordance with the particular operating conditions. It is also possible to manufacture a bidirectional lock-up cylinder. For details, refer to “Made to Order” on page 2126. Due to the nature of its construction, a lock-up cylinder has a play of approximately 0.5 mm to 1 mm in the axial direction. Therefore, if an external stopper is used to stop the piston rod and the lock is engaged, the piston rod will shift in the amount of its axial play. 6. To effect an intermediate stop, take the cylinder’s stopping precision and overrun amount into consideration. Because the lock is applied by mechanical means, the piston will not stop immediately in response to a stopping signal, but only after a time lag. This lag determines the amount of the overrun of the piston stroke. Thus, the range of the maximum and minimum amounts of the overrun is the stopping precision. . Place the limit switch before the desired stopping position, only in the amount of the overrun. . The limit switch must have a detection length (dog length) of the overrun amount + α. . For SMC’s auto switches, the operating range are between 8 and 14 mm. (It varies depending on a switch model.) When the overrun amount exceeds this range, self-holding of the contact should be performed at the switch load side. . For stopping accuracy, refer to Series CLJ2 (P. 709), Series CLM2 (P. 720), Series CLG1 (P. 736), and Series CL1 (P. 747) respectively. 7. In order to further improve stopping accuracy, the time from the stop signal to the operation of the lock should be shortened as much as possible. To accomplish this, use a device such as a highly responsive electric control circuit or solenoid valve driven by direct current, and place the solenoid valve as close as possible to the cylinder. 8. Be aware that the stopping accuracy is influenced by changes in the piston speed. The variance in the stopping position increases if the piston speed changes, such as due to load fluctuations during the reciprocal movement of the piston. Therefore, take measures to ensure a constant piston speed immediately preceding the stopping position. Furthermore, the variances in the stopping position increases when the piston is effecting a cushioning stroke or during acceleration after starting its movement. 9. When unlocking is performed, if the thrust is applied to the piston, unlocking will not be easily done. To avoid that, ensure that unlocking should be performed before the thrust is applied to the piston. Overrun amount Stop signal 702