Mechanical guard device

Careful design of guards is vital. An ineffective guard can be worse than none at all, as it can give rise to a false sense of security. Emergency shutoff devices may be needed, in addition to electrical and mechanical guarding. 

Safeguards include guards, devices, distance, or location. Safeguards for machines fall into two major groups mechanical power transmission safeguards, and point-of-operation safeguards. 

Mechanical-power presses are required to have switches and brakes that are operator proof The size of some presses makes it imperative that they are switch-guarded as well as mechanically guarded. This section describes what actions must be taken to produce the most failsafe device possible. Minimum braking action and the proper brakes that must be installed on presses of differing specifications are outlined. Criteria for the use of presence-sensing devices and their proper utilization is described. 

Figure 4.3.12 Electro-mechanical delay device (Courtesy EJA Ltd, Guard master)...

The many options available for lift trucks f l into two classes vehicle specialties, which include controls, transmissions, guards, etc. and accessories, which are devices that handle specific types of loads (Fig. 21-55). Included in this second category are high-lift masts, up to 7 m (24 ft) handhng attachments for circular products, such as drums and roll goods attachments such as carton clamps and the fork side-to-side shifting mechanism. 

Examine apparatus for general mechanical condition, including guards and other safety devices. 

Electric field transducers can also be used. They generate a capacitive field in a hazard area. Any grounded object in the field can he detected. Operators working in that area are grounded and can he sensed by this method to stop the machine before its activation. These are different guards and safety devices that are normally used to avoid mechanical hazards. 

A type of machine interlock system that has a mechanical device that requires a specific time period for a guard to be released after the power has be shut off... 

Guards and sentries are needed when mechanical or electronic surveillance devices are inadequate. Of course, this may require 24-hour, 7-day-per-week coverage or a minimum of four full-time personnel. Depending on needs, animals may provide an adequate level of security, and systems can be adjusted so animals do not trigger them. Guards must be continually trained and notified of specific threats. 

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