What is the definition of "two-handed trip device"?
A machine start mechanism that requires simultaneous pressure on two separate controls to activate the machine or machine cycle. Once the machine starts, the operator may let go of the device and the machine will continue to run.

Learn more about two-handed trip device in the class Machine Guarding 140 below.


Safety Training


Class Information
Safety Training Tooling U-SME classes are offered at the beginner, intermediate, and advanced levels. The typical class consists of 12 to 25 lessons and will take approximately one hour to complete.
Class Name:Machine Guarding 140
Description:This class covers basic machine guarding practices and devices and includes information on hazardous machine components, motions, and actions.
Prerequisites: none
Difficulty:Beginner
Number of Lessons:16
Language:English, Spanish
 
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Class Outline
  • Objectives
  • The Importance of Machine Guarding
  • Hazardous Mechanical Components
  • Hazardous Machine Motion
  • Hazardous Machine Action
  • Hazardous Machine Activities
  • Requirements for Basic Safeguarding
  • Safeguarding Methods
  • Machine Guards
  • Safeguarding Devices
  • Safeguarding Foot Controls
  • Safeguarding by Location
  • Safeguarding by Feeding and Ejection Method
  • Lockout/Tagout
  • Training
  • Summary
  
Class Objectives
  • Explain the importance of machine guarding.
  • Match the types of mechanical components with their descriptions.
  • Match the types of mechanical motion with their descriptions.
  • Match the types of machine actions with their descriptions.
  • Describe the benefits of creating categories of machine activities.
  • Identify requirements of OSHA's machine guarding standard.
  • Distinguish between machine guards and safeguarding devices.
  • Match the types of machine guards with their descriptions.
  • Match the types of safeguarding devices with their descriptions.
  • Describe how foot controls differ from many other types of controls.
  • Identify examples of safeguarding by location.
  • Identify methods of safeguarding by feeding and ejection.
  • Describe the purpose of lockout/tagout in relation to machine guarding.
  • Describe the role of training in machine guarding.

Class Vocabulary

Vocabulary TermDefinition
adjustable guard A guard that may be moved or reconfigured to allow for different types of production, such as different sizes of stock or raw materials.
amputation Loss of a limb or body part either through surgery or an accident.
awareness barrier A visual means of warning employees that they are entering hazardous areas. Caution tape and yellow lines on the shop floor are examples.
bending action A combination of a downward or sideways punch-like movement and a blunt tool used to shape metal or other materials without cutting.
conveyor A device such as a belt or set of rollers that is used to move items from one location to another.
cutting action A combination of a tool with sharp cutting edges and a motion, such as rotation, used to remove material and make a cut.
ejection method The way in which stock or parts exit the point of operation on a machine.
feeding method The way in which stock or parts enter the point of operation on a machine.
fixed guard A machine guard that is attached to the machine with screws or other devices that require a tool for removal. Fixed guards are generally safer than other types because they are harder to remove.
foot control A machine start device that is activated with the operator's foot. Foot controls require guarding to prevent accidental activation.
gate A moveable barrier often used on metal cutting machines. Gates often have slides or hinges that allow them to be opened while remaining attached to the machine.
in-running Circular motion involving two or more mating parts that can cause pinch-type injuries at the point where the parts converge.
interlocking guard A guard that shuts off or disengages the power whenever it is opened or pushed out of position.
light curtain A type of presence-sensing device that uses an optical mechanism to create a continuous beam of light around hazardous components. When the beam is interrupted by the operator's body or hand or another object, the machine stops cycling.
lockout/tagout A method of protecting employees from accidental machine startup through proper locking and labeling of machines that are undergoing maintenance.
machine action A combination of the task that a machine performs and the motion required to perform it.
machine guard A rigid device that encloses a hazardous area on a machine. Machine guards often partially cover the point of operation while allowing necessary access.
machine guarding A method of preventing worker injury by keeping body parts from entering hazardous areas of the machine or by keeping flying debris from exiting the machine.
machine safeguarding The combination of methods, requirements, machine guards, safeguarding devices, and other tools and practices used to keep employees safe from machine hazards.
machine table The surface on which stock or work is located and fixtured on many types of machines. The machine table is often capable of reciprocating movement.
mill A multi-point tool that is used to remove material from the surface of a workpiece.
Occupational Safety and Health Administration A government agency under the U.S. Dept. of Labor that helps employers reduce injuries, illnesses, and deaths in the workplace.
point of operation The area where the work actually takes place. It is the place where the tool and the workpiece converge.
positioning apparatuses Machine components, such as worktables or mechanical arms, that move in order to situate parts or tools.
potential energy Power that is stored or suppressed or that exists because of its position and the effects of gravity. Machines with large components that raise and lower, such as a press, contain potential energy that becomes kinetic energy when it is released.
power transmission apparatuses Machine components like belts and pulleys that translate energy, such as electricity, into motion.
presence-sensing device A mechanism used to detect the location of people or objects near hazardous areas of machine. Presence-sensing devices often use pressure-sensitive mats or light curtains.
presence-sensing mat A type of rug that contains sensors that detect weight or pressure. When placed on the floor around hazardous areas of the machine, these mats can sense an operator's presence and disengage the machine.
press A machine with a stationary base and an upper ram that moves along a vertical axis to shear, bend, or form sheet metal.
pullback device A wrist device that pulls the operator's hands away from the point of operation or other hazardous areas when the machine cycles.
punching action A combination of a reciprocating movement and a punch used to cut or form shapes into metal and other materials.
push stick A device, often made of wood, that allows the operator to feed stock into the point of operation while keeping hands out of harm's way.
reciprocation Back-and-forth or up-and-down motion that can cause crushing or pinch-type injuries.
restraint device A wrist device that restrains the operator's hands and prevents them from crossing into the point of operation or other hazardous areas.
rotation Circular motion, such as with a spindle or wheel, that can catch body parts, clothing, or hair.
safeguarding device A switch, bar, sensor, or other mechanism that interrupts the machine's operating cycle to prevent workers or any parts of their bodies from entering dangerous areas during machine cycles.
self-adjusting guard A guard that covers the hazardous area until stock is pushed into the point of operation and moves the guard.
sensing device A mechanism that can detect the operator's entry or presence in a hazardous area and shut down the machine.
shearing action A combination of a downward movement and an angled blade used to separate metal and other materials.
stored energy Power that has not been used or dissipated. Stored energy can take many forms, such as unused electricity or tension in a spring.
tongs A scissor-like device that allows operators to place and remove stock or parts at the point of operation.
toolholder A mechanism used to rigidly hold a cutting tool in place during machining.
transversing Straight-line movement, such as with a belt or chain, that can catch body parts, clothing, or hair.
trip control A type of presence-sensing device that uses a trigger mechanism to disengage the machine when the operator accidentally or purposefully presses a bar, a wire, or another type of switch.
two-handed control A machine start mechanism that requires simultaneous and continuous pressure on two controls to activate the machine and keep it running.
two-handed device A machine start mechanism that requires simultaneous pressure on two separate controls to activate the machine or machine cycle.
two-handed trip device A machine start mechanism that requires simultaneous pressure on two separate controls to activate the machine or machine cycle. Once the machine starts, the operator may let go of the device and the machine will continue to run.
type A gate A moveable barrier that prevents operator access during the entire machine cycle.
type B gate A moveable barrier that prevents operator access while the cutting tool enters the part, but allows access as the tool exits the part.
wrist device Straps that connect the operator's wrists to specific points on the machine. The straps keep worker's hands out of the point of operation.