shrink wrapper safety

[Pierre]

What is a "Tennis-racket" safety photoeye?

At the botton leading edge of the rotary arm, you install it.

It looks exactly like the frame of a tennis racket. It point toward the front of the rotary arm direction. It is made of flexible plastic. Its about 1-1/2 foot long.

Inside the frame, there is no strings, you install a reflector.

At the top of the arm, verticaly, looking down on the Tennis racket which holds the reflector, you install the photoeye.

When the wrapper does its first turn on slow speed, if this racket hits anything, you stop the system.

Ask the manufacturer, he has to know about it. Its standard in wrappers.

Once the system is rotating, if any photoeye detects anything... STOP!

 

[Mylo]

Hello all ,

not familliar at all with shrink/strech units, but I am in a OEM company, a lot of our machinery employs muting of circuits to facilitate operator intrusion into the "Work area". Typically if i can say that we utilise machine interlocks wired into the safety circuits, when all moving parts are in a home position (Safe) they close there corresponding latches, thus enabling the operator to safely bypass the lightcurtain at that point. if one of these moving parts moves off its home position the circuit drops power to these actuators, in large machines we can use a wide area safety light curtain to establish whether the operator is inside or outside the work area for startup. THis does limit the start/stop of the machine but is Foolproof, nessesary in this line of work, and i am certainly in aggreement with all previous posts, the OEM should have installed this or similar,

Mylo

 

[Sparky]

Possible solution

We have had the same problems with our stretch wrapper and palletizing robot. What I ended up doing for the infeed and out feed was designing a light curtain that instead of being mounted vertical, it will be mounted horizontal. This can then be programmed so that in order for the machine to start its sequence all curtain inputs must have been "on" at the same time. Any thing else shuts the system down.
I timed the conveying speed gave it a small window of error and sized the curtain to within two inches of the length of the pallet. Unless three people dumb enough to enter at the same time holding hands walking very close to each other then the system shuts down. I also, like was mentioned earlier, placed one photo eye ant the trailing edge of the curtain. This photo eye is wired direct to a relay and on to the e-stop circuit the supply to the relay is controlled by the PLC. The output to the relay is on unless the curtain latch has been made; this just added a little redundancy and safety to the system.

 

[grey]

re post 18...could you provide some more details?....it looks like our plant is implementing a system like this you have.
There is 4 areas of operation ...an entry area for pallet, a pallet waiting , then the pallet being wrapped and a pallet at the exit.
One problem is the pallet being wrapped cant be interupted by normal operation at entry and exit. Also we dont want to push a reset button.

we have placed 4 eyes horizontal at entry rollers and 4 eyes horizontal at exit rollers. plc program not written yet.

tennis racket idea may be added but the arm rotates so fast in high speed it will not stop anyway quick enough for this to save anyone if they were near the squeeze point of the side supports.

....unless arm can be made to stop dead in its tracks....I doubt it though or Orion would do this.

model wrapper is an Orion MA 55

 

[seppoalanen]

Hope your trip to Appleton wasn't too traumatic
Hoot

Trip was a pleasure and there ware friendly people ! Ps. I have been one week in Millwaukee too !