Tsubaki Introduces Full Range of Overload Protection and Control Devices

Mechanical safety devices within the SAFCON range include the Torque Guard, Torque Limiter and Axial Guard. Mechanical control devices include the Torque Keeper and Mini Keeper, while electronic safety and control devices include the Shock Relay and Shock Monitor. This complete range of products has been designed to prevent costly breakdowns due to overload conditions by stopping machine operation before damage occurs.

Within the mechanical safety devices range, the Torque Guard is a ball and detent mechanical device that offers instant and complete disengagement, with accurate and consistent torque setting. It is ideal for more sophisticated equipment that may be prone to jams, and where users need a consistent and reliable trip point with quick resetting and little or no backlash, so that production is maintained and each line stays in sync with where it left off.

This synchronisation is assured by the one-position design that ensures each ball returns to its unique location when it resets so that equipment resumes its work exactly where it was before the jam or overload. The Torque Guard automatically resets by inching either the driver or load side; an optional sensor is available for linking to an audible alarm.
The torque guard is easy to set and adjust with its built-in meter and indicator having distinct torque setting points for easy verification.

The Torque Limiter is a simple and inexpensive mechanical device. Easy to install, it attaches to a shaft and holds the drive or driven sprocket, gear or sheave. It reacts instantly to an overload by slipping and absorbing the force, preventing damage to the equipment. The Torque Limiter has been designed to offer long life, consistent performance, with specially formulated friction materials that extend the operating life and improve repeatability of the slip point.

For mechanisms where the load acts in the linear rather than rotary direction, the SAFCON range includes the Axial Guard. This new type of mechanical overload device offers a highly accurate and repeatable trip point. The load setpoint is easily adjusted by turning a screw. When overload occurs, the Axial Guard immediately trips and the connection between the drive side and load side is cut off. To reset the Axial Guard, all that is needed is a small pull or push in the opposite direction, enabling production to be restarted quickly and downtime to be minimised.

Mechanical control devices within the SAFCON range include the Torque Keeper and its smaller brother the Mini Keeper – slipping clutch brakes that set new standards for size, weight and torque stability. For heavy duty applications, the Torque Keeper is a slipping clutch and brake that offers longer life when compared to conventional brake linings, combined with low torque fluctuation. Because the torque fluctuation is very small, stable torque can be transmitted, even when there is frequent repeated slippage. The use of aluminium flanges mean the Torque Keeper is light weight, while the special design makes for significant space savings, with the Torque Keeper much more compact than other braking devices.

The Torque Keeper offers a wide torque range, while indicators make torque setting easy. Operation is simplified through the use of an adjusting nut. Fine chemical fibres for the friction surface give much longer life when compared with other types of brake lining.

For lighter duty applications, the Mini Keeper is a highly accurate, light and compact slipping clutch and brake, constructed from fine chemical fibres and engineering plastic.
For electronic monitoring and control, the SAFCON range includes the Shock Relay – a current monitoring device that quickly detects motor overload, and outputs an emergency shutdown signal to prevent the motor from burning out. The Shock Relay protects against unexpected shock loads, overloads and underloads before damage occurs. It outputs a signal when the motor current exceeds a preset value for a preset time. For example, when a foreign body is caught up in a conveyor, the shock relay sends a signal to trigger an emergency stop, minimising equipment damage.

The Shock Relay provides the flexibility to ignore small current variations by way of the shock time function, where an adjustable start time means that it doesn’t engage during start up when the motor’s current draw is greater than the running current. Abnormal signals are only output under abnormal conditions. Also, unlike mechanical devices such as shear pin sprockets, the shock relay resets at the touch of a button, and it is suitable for use with virtually any kind of equipment that’s driven by an electric motor.
The Shock Monitor is a powerful monitoring safety & control device that detects even the minimal variations in load by monitoring input power. Almost completely unaffected by source voltage variation, the units can be used with a wide range of frequencies.