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154 Machine Safeguarding: Basic
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Machine Guard Construction

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.

Machines guards must be substantial. Metal is best. Wood is not recommended.

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 ever 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.

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 is generally expanded, 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 are not generally 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.

Knowledge Check Choose the best answer for the question.

1-8. What is one advantage of user-built machine guards?