Pneumatic safety bumper

[davidinindy]

We have fully pneumatically powered turntables that have safety flaps than stop motion if they contact a person or item.
Right now, they are a hinged steel flap, that is spring-loaded, and when compressed, it closes a pneumatic valve, which in turn shuts off the pneumatic motors.
Admittedly, these flaps can be hard on the shins, or ankles if they do hit you before stopping the machine. But they do the trick.
Our customer wants to go to something softer.
I've seen the rubber bumpers for gates and garage doors, but they are designed to trigger a pressure switch to turn the pneumatic pressure into an electrical signal to turn of an electric motor.
I've Googled my brains out, and have not found anything that would keep the pneumatic signal to send to the pilot valve to shut the motor off.
We really don't want to add electrical to these machines.
Anyone have any suggestions?

David
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Quote: "If it ain't broke, I must not've fixed it good enough"

 

[BrianPetersen]

Is this equipment subject to risk assessment such as ISO 13849, ISO 10218, RIA R15.06, or other such standards?

 

[rb1957]

the difficultly with making the contact more pliable is … how does the deactivation circuit know to act ?

right now you've got a stiff steel plate hitting something, deflecting "rigidly", and causing the deactivation loop to act.

another day in paradise, or is paradise one day closer ?

 

[Jboggs]

Google "air logic valves". Lots of options out there.

 

[hydtools]

Lighter spring. Longer lever arm on the flap arm.

Ted

 

[RobWard]

Some foam or rubber glued to the steel flap?

"I love deadlines. I love the whooshing noise they make as they go past." Douglas Adams

 

[FACS]

I do not know what the design looks like.

Instead of a spring to hold the flap in place, design a detent to hold the flap in place. The detent can be bi-directional.

When the flap is pushed off the detent, that can trigger a pneumatic switch that does not need a lot of pressure to actuate, maybe a whisker or lever on the switch to multiply the force.

This will force the operator to have to set the plate back in position into the detent - a re-set.

The detent can be adjusted for a comfortable release pressure.

Alternative Idea:

You could also use a spring to pull the plate into a switch after it releases from the detent if you need more switch actuation force.

1) Plate has a spring that pulls it into a switch.
2) Pivot the plate off of the switch, forcing the spring to pull the plate.
3) Hold the plate into position with a detent set with just enough force to hold the plate.
4) When the plate is bumped, it pushes it off of the detent using a light touch.
5) Once off of the detent, the spring takes over, actually moving away from your shin thus saving it pain.
6) The spring forces the plate into the switch plunger or whatever.

So the spring will do the work for you