Industrial Machinery Accidents: What you need to know (PART B: Defective Jog Controls)

by Daniel J. O'Brien [email protected]

Published: 6/21/12

There can be various design defects in industrial machines, and Part A of this article focused on improper guarding of heavy machinery.  Part B addresses the design defects with jog controls/buttons on industrial machines.

Having Only A Single Jog Control is a Design Defect on Industrial Machines

It is very common for operators to jog the machine to clear out a jam in the machine.  Common industry practice utilizes two button or “dual button” controls when the control is located within arm’s reach of a point of operation nip point, pinch point, shear point, etc.

Under the two button design concept, an operator must simultaneously push two separate buttons -- one with each hand -- in order for the machine to cycle. This design makes it impossible for an operator to jog the machine with one hand while the other hand is at or near a nip point. 

Therefore, if the machine has a single jog control within arm’s reach of the in-running nip point, there is a design defect.

Absence of Time Delay and Warning Horn is Another Design Defect   

Another design defect with jog controls is the absence of a time delay and warning horn. In many types of industrial machinery, a delay/warning signal is incorporated into the jog and run circuits. 

These systems require the operator to push the jog button and to keep the button depressed for a certain specified period of time, typically three to five seconds. During that period of time, the machine does not cycle. Rather, an audible signal sounds. If the jog button is released during the signal, the machine will not cycle. It will only begin to cycle at the conclusion of the time delay during which the warning signal is audible.

This gives operators an opportunity to remove their free hand from any in-running nip point, and vastly reduces the potential for the type of accident scenario involved in this case -- an operator inadvertently depressing the jog button before removing the other hand from the in-running nip point.

If the jog buttons are not properly designed, it is very likely that the operator's hand or fingers could be rolled into the nip point and sustain a crush injury.

Help After Being Injured on Industrial Machine

If you were injured in an industrial machinery accident and would like to have your case evaluated by an attorney,  please contact our experienced Philadelphia, PA and New Jersey industrial machinery accident attorney for a free, no obligation consultation at 877.944.8396.

Having your industrial machinery accident properly investigated is crucial to determine not only the liability of all parties such as the machine manufacturer, but also the types of claims which may be made.

Related Article:

• Industrial Machinery Accidents - What You Need To Know About Design Defects (Part A: Improper Guarding)