To prevent employee amputations, you and your employees must first be able to recognize the contributing factors, such as the hazardous energy associated with your machinery and the specific employee activities performed with the mechanical operation.
Understanding the mechanical components of machinery, the hazardous mechanical motion that occurs at or near these components and specific
employee activities performed in conjunction with machinery operation will help employees avoid injury.
Hazardous Mechanical Components
Three types of mechanical components present amputation hazards:
Point of Operation is the area of the machine where the machine performs work – i.e., mechanical actions that occur at the point of operation,
such as cutting, shaping, boring, and forming.
Power-Transmission Apparatus is all components of the mechanical system that transmit energy, such as flywheels, pulleys, belts, chains, couplings,
connecting rods, spindles, cams, and gears.
Other Moving Parts are the parts of the machine that move while the machine is operating, such as reciprocating, rotating, and transverse moving
parts as well as lead mechanisms and auxiliary parts of the machine.
Hazardous Mechanical Motions
A wide variety of mechanical motion is potentially hazardous. Here are the basic types of hazardous mechanical motions:
Rotating Motion (Figure 1) is circular motion such as action generated by rotating collars, couplings, cams, clutches, flywheels, shaft ends, and spindles that may grip clothing or otherwise force a body part into a dangerous location. Even smooth surfaced rotating machine parts can be hazardous. Projections such as screws or burrs on the rotating part increase the hazard potential.
Reciprocating Motion (Figure 2) is back-and-forth or up-and-down motion that may strike or entrap an employee between a moving part and a fixed object.
Transversing Motion (Figure 3) is motion in a straight, continuous line that may strike or catch an employee in a pinch or shear point created by the moving part and a fixed object.
Cutting Action (Figure 4) is the action that cuts material and the associated machine motion may be rotating, reciprocating, or transverse.
Punching Action (Figure 5) begins when power causes the machine to hit a slide (ram) to stamp or blank metal or other material. The hazard occurs at the point of operation where the employee typically inserts, holds, or withdraws the stock by hand.
Shearing Action (Figure 6) involves applying power to a slide or knife in order to trim or shear metal or other materials. The hazard occurs at the
point of operation where the employee typically inserts, holds, or withdraws the stock by hand.
Bending Action (Figure 7) is power applied to a slide to draw or stamp metal or other materials in a bending motion. The hazard occurs at the point of operation where the employee typically inserts, holds, or withdraws the stock by hand.
In-Running Nip Points (Figure 8), also known as “pinch points,” develop when two parts move together and at least one moves in rotary or circular motion. In-running nip points occur whenever machine parts move toward each other or when one part moves past a stationary object. Typical nip points include gears, rollers, belt drives, and pulleys.
Employees operating and caring for machinery perform various activities that present potential amputation hazards.
- Machine set-up/threading/preparation,*
- Machine inspection,*
- Normal production operations,
- Clearing jams,*
- Machine adjustments,*
- Cleaning of machine,*
- Lubricating of machine parts,* and
- Scheduled and unscheduled maintenance.*
* These activities are servicing and/or maintenance activities.
You can help prevent workplace amputations by looking at your workplace operations and identifying the hazards associated with the use and care of the machine. A hazard analysis is a technique that focuses on the relationship between the employee, the task, the tools, and the environment. When evaluating work activities for potential amputation hazards, you need to consider the entire machine operation production process, the machine modes of operation, individual activities associated with the operation, servicing and maintenance of the machine, and the potential for injury to employees.
The results from the analysis may then be used as a basis to design machine safeguarding and an overall energy control (lockout/tagout) program.
This is likely to result in fewer employee amputations; safer, more effective work methods; reduced workers’ compensation costs; and increased employee
productivity and morale.
[Content with recognition to OSHA]