AMETEK 1025 Foot & Palm Switches - Manual (Page 17)

13 Operating Manual
Chapter 3: Operating Instructions
5. Using the stop angle from the previous graph, add the desired brake wear
allowance, typically 10-15%. This is the included angle setting between the top
stop cam limit and the brake monitor cam limit switch. This setting should be
locked or adjusted only by authorized personnel.
6. If the brake wear allowance on the brake monitor was 10%, add 20% to the
safety distance measurement used to set the two-handed controls, or electronic
guards such as optical presence sensors. Increasing the stop time will cause
the brake monitor to activate and the operator will have an additional 10%
safe distance margin.
3.9: Using the Safetimeter to Aid in Setting
Cam Limit Switch Brake Monitors
Cam limit switch brake monitors check the angular travel of a press during a top stop,
thus determining the brake effi ciency by determining the total included stop angle
between the normal top stop cam switch and the brake cam switch. The function of
the top stop cam is to bring the press to a stop at, or very near, the top of the press
stroke. Very often, the exact parked position of the press is affected by the type
of part being made. Most often, users favor a parked position typically 5 degrees
after top dead center.
The top stop cam switch is set to disengage the clutch, and apply the brake at
some point on the up stroke in order to allow the press to coast to the desired top
stop position. As die weight, brake wear and other response factors increase, this
setting may have to be adjusted to operate earlier in the stroke to compensate for
this additional wear. This adjustment results in parking the press at the desired top
stop location but ignores the fact that this setting may also affect an overtravel cam
switch used as a brake monitor.
Adjusting the top stop cam, without adjusting the brake monitor cam, causes longer
stop times to occur before the brake monitor activates.
If the current safety distance is not increased, a dangerous situation can exist
whereby the operator’s controls or safeguard devices may be too close to the point of
operation. The top stop brake monitor is trying to judge the stop effi ciency on the
down stroke based on the test made on the upstroke. To do this, stopping time and
stop angle on both down and up stroke should be known. Ideally, they should be the
same, and in a press where counterbalances are used, they must be the same.