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Course 726 - Introduction to Machine Guarding

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Machine Guard Construction

Introduction

Today many builders of single-purpose machines provide point-of-operation and power transmission safeguards as standard equipment. However, not all machines in use have built-in safeguards provided by the manufacturer.

Advantages of Builder-Designed Guards

Guards designed and installed by the builder offer two main advantages:

  • They usually conform to the design and function of the machine.
  • They can be designed to strengthen the machine in some way or to serve some additional functional purposes.

Advantages of User-Built Guards

User-built guards are sometimes necessary for a variety of reasons. They provide the following advantages:

  • Often, with older machinery, they are the only practical safeguarding solution.
  • They may be the only choice for mechanical power transmission apparatus in older plants, where machinery is not powered by individual motor drives.
  • They permit options for point-of-operation safeguards when skilled personnel design and make them.
  • They can be designed and built to fit unique and even changing situations.
  • They can be installed on individual dies and feeding mechanisms.
  • Design and installation of machine safeguards by plant personnel can help to promote safety consciousness in the workplace.

Disadvantages of User-Built Guards

User-built guards also have disadvantages:

  • User-built guards may not conform well to the configuration and function of the machine.
  • There is a risk that user-built guards may be poorly designed or built.

Point-of-Operation Guards

Point of Operation Guard

Point-of-operation guards are designed to prevent workers from accidentally or intentionally inserting a finger, hand, foot, or any other body part into the operating machine.

Point-of-operation safeguarding is complicated by the number and complexity of machines and also by the different uses for individual machines. For these reasons, not all machine builders provide point-of-operation guards on their products.

In many cases a point-of-operation guard can only be made and installed by the user after a thorough hazard analysis of the work requirements. Poorly designed, built or installed guards may create a hazard rather than eliminate one.

To be effective they must safeguard the employee while allowing the work to continue with minimum disruption to the production process.

Mechanical Power Transmission Apparatus Guarding

Robots are used for replacing humans who were performing unsafe, hazardous, highly repetitive, and unpleasant tasks

A significant difference between power transmission guards and point-of-operation guards is that the former type needs no opening for feeding stock. The only openings necessary for power transmission guards are those for lubrication, adjustment, repair, and inspection. These openings should be provided with interlocked covers that cannot be removed except by using tools for service or adjustment.

To be effective, power transmission guards should cover all moving parts in such a manner that no part of the operator's body can come in contact with them.

Fixed Guard and Robot

Guard Material

Under many circumstances, metal is the best material for guards. Guard framework is usually made from structural shapes, pipe, bar, or rod stock. Filler material generally is expanded or perforated or solid sheet metal or wire mesh. It may be feasible to use plastic or safety glass where visibility is required.

Guards made of wood generally are not recommended because of their flammability and lack of durability and strength. However, in areas where corrosive materials are present, wooden guards may be the better choice.

Instructions

Before beginning this quiz, we highly recommend you review the module material. This quiz is designed to allow you to self-check your comprehension of the module content, but only focuses on key concepts and ideas.

Read each question carefully. Select the best answer, even if more than one answer seems possible. When done, click on the "Get Quiz Answers" button. If you do not answer all the questions, you will receive an error message.

Good luck!

1. Guards designed and installed by the builder offer two main advantages:

2. Which of the following is an advantage of installing user-built guards?

3. To be effective, power transmission guards should cover all moving parts in such a manner that ______ cannot come in contact with them.

4. Design and installation of machine safeguards by plant personnel can help to promote safety consciousness in the workplace.

5. Guards made of wood generally are recommended because of their low flammability and high durability and strength.


Have a great day!

Important! You will receive an "error" message unless all questions are answered.