Different Types of Machine Guards and Safeguarding 

What are Machine Guards and Safeguarding?

Safeguarding and machine guards are a part of the process of preventing contact between moving mechanical parts and skin or clothing. It can also include controlling emitted particles or sparks. 

Some normal applications include gates or panels which cover the moving parts. Using guard enclosures to make sure the machine is not operating without the right conditions is another good way to safeguard machines. There are plenty of size and mobility options depending on the needs of the machine (EHS).

Why Are They Important?

The purpose of machine guarding is to protect the machine operators and other employees in the work area from hazards created during the machine’s normal rotation. Because of this, it is a crucial component of safety across all industries. 

Safeguarding is required to maintain a safe work environment. According to OSHA, machine guarding is the first line of defense to protect employees from machine-related injury.

Complying With OSHA Requirements

There are many steps that must be taken in order to adhere to OSHA requirements. The first one is to identify all of the potential hazards in the workplace. Once the hazardous areas are identified, safeguarding the machinery will come afterward and with ease. 

Once the hazards are identified, machine safeguards must follow six standards in order to be compliant with OSHA’s requirements:

1. Prevent contact – The safeguard must prevent clothing and other body parts from coming into contact with the machine.
2. Stay secure – Machine guards should be made of high-quality materials and secured to the machine. Employees should not easily be able to tamper with or remove the machine guard.
3. Stop falling objects – The safeguard should ensure that no objects can fall into or disturb the moving parts.
4. Allow safe maintenance – Employees should ideally be able to lubricate and inspect the machine without going beyond the safeguard.
5. Create no interference – Any safeguard that prevents employees from doing their job quickly and efficiently may be ignored depending on the operation and type of machine. This can quickly lead to injury.
6. Introduce no new hazards – Safeguards should not impede or interrupt robotic machinery. They must not have any burrs, jagged edges, or rough materials, as this defeats their purpose. 

Moving Mechanical Parts

A moving mechanical part is hazardous regardless of any other factors. Employees that work around moving machines are at risk of getting injured at any moment. There are many different types of hazardous motions that have unique points at which they could make contact with clothing or skin. Some of these basic hazardous motions are:

• Rotating
• Punching
• Shearing
• Bending
• Reciprocating
• Transversing actions
• Cutting

Each piece of machinery has its own unique mechanical and non-mechanical hazards. Machines can cause a variety of injuries ranging from minor abrasions, burns, or cuts to severe injuries such as fractures, lacerations, crushing injuries, or even loss of limb. Because of the risks, each machine must have adequate safeguards to protect operators and any employees that work around the machine. 

Different Types of Machine Guards

There are many different types of machine guards. According to OSHA, the most common types of guards can be categorized into one of four general types of machine guards:

1. Fixed
2. Interlocked
3. Adjustable
4. Self-adjusting 

Each type of machine guard has their own advantages and disadvantages. We will go over and discuss what these guards are throughout the next few sections. 

Fixed

A fixed guard is a permanent part of the machine. It provides a barrier and does not depend on the moving parts to function. It should be constructed of any material that is substantial enough to withstand whatever impact it may receive and be able to endure prolonged use. This type of machine guard is commonly preferred over other types because of its simplicity. 

There are some great advantages that go along with fixed machines. For example, they:

• Can be constructed to suit many specific applications
• Can provide maximum protection
• Usually requires a minimal amount of maintenance
• Can be suitable for high production, repetitive operations

There are a few limitations as well. Fixed guards can interfere with operator visibility. When a fixed guard does need to be repaired or adjusted, it has to be completely removed from the machine until it is fixed. Because of this, a temporary means of protection will need to be used while it is being repaired.

Interlocked

When this type of guard is opened or removed, the tripping mechanism and power automatically shut off and disengage, which stops the moving machine parts. The machine cannot cycle or be started again until the guard has been properly put back in place. An interlocked machine guard could use electrical, mechanical, hydraulic power, or any combination of these.

Interlocked guards benefit employees by providing maximum protection and allowing access to the machine for removing jams without the time-consuming removal of the fixed guards.

But these types of guards also require careful adjustment and maintenance, which takes up a lot of time. Plus, interlocked guards can be easily disengaged, meaning a bump in the machine could cause a jam. This hurts both the machine and employee productivity. 

Adjustable

Adjustable guards are useful because they allow flexibility in the accommodation of various sizes of stock. The term “stock” refers to raw material from which something is manufactured. Adjustable guards provide a barrier that can be adjusted to facilitate different production operations. An advantage of an adjustable safeguard is that it can be constructed to suit many specific applications. 

Unfortunately, this type of guard may have more disadvantages than advantages. Here are a few examples of the limitations this type of guard is associated with:

• Hands could enter the danger area, meaning protection may not be complete at all times
• It may require frequent maintenance and adjustment
• The guard might be made ineffective by the machine operator
• It might interfere with visibility

Self-adjusting

The openings of these barriers are determined by the movement of stock. As the operator moves the stock into the danger area, the guard is pushed away, providing an opening that is only large enough to admit the stock. 

After the stock is removed, the guard returns to the rest position. The guard protects the operator by placing a barrier between them and the danger area. These types of guards could be constructed of substantial material. Self-adjusting guards offer different degrees of protection. (OSHA).

Some limitations of self-adjusting guards include not always providing maximum protection, interfering with operators’ visibility, and requiring a lot of maintenance and adjustment. 

Safeguard Devices

Safeguard devices work towards eliminating hazards for machine operators and employees. These devices have many different functions, all of which protect employees. Some examples of these functions would be:

• Stopping the machine if a hand or part of the body is inadvertently placed in the danger area
• Restraining or withdrawing the operator’s hands from the danger area during operation
• Requiring the operator to use both hands on machine controls
• Providing a barrier that is synchronized with the operating cycle of the machine

There are six commonly used safeguard devices that all work towards protecting employees from getting hurt. These six devices will be discussed in the next couple of sections.

Six Common Types of Devices

1. Presence-Sensing Devices – These devices use a system of light or radiofrequency sources and controls which can interrupt the machine’s operating cycle. 
2. Pullback Devices – A pullback device uses a series of cables attached to the operator’s hands, wrists, or arms. 
3. Restraint Devices – The restraint device uses cables or straps that are attached to the operator’s hands at a fixed point. 
4. Safety Trip Controls – Safety trip controls provide a quick means for deactivating the machine in an emergency situation. A pressure-sensitive body bar, when depressed, will deactivate the machine
5. Two-Hand Control Devices – The two-hand control device requires constant concurrent pressure by the operator to activate the machine
6. Two-Hand Trip Devices – The two-hand trip device requires concurrent application of both the operator’s control buttons to activate the machine cycle, after which the hands are free.

Always be Armed With Knowledge

It is important for employees to be able to work safely around machines and understand how to utilize machine guards and safeguard devices. It is the employer’s responsibility to provide safety training for them. An online safety course provider such as Safety Provisions, Inc. will be able to help you with all required training your employees need.

This safety training should teach OSHA’s requirements for machine guards and safeguard devices. It should also teach employees how to inspect their equipment and who to report to if the equipment needs maintenance. Knowing how to utilize the safety tools they are provided with will be workers’ best chance at staying safe in their workplace.