electric latch

B

BobP122

Guest
Hi
I have a one touch electric can opener (that no longer works).
How it (used to) work:
-Place on a can
-Press switch (momentary)
From there on it turned and cut off the top of the can and stopped
when finished.
I curious about how it worked.
Specfically: How does the momentary switch "latch" or stay closed.
(There aren't any electronic ics).
Batteries then turn gears till the cutting is completed. Somehow a
gear (I think) breaks the circuit and opearations is ended.
The entire circuit is 2 AA batteries (3 volts), a motor, gears and
switches. No electronics or digital logic.
Thanks
BobP
 
On Sat, 18 Jul 2009 09:55:19 -0700 (PDT), BobP122
<JohnNicolet@sympatico.ca> wrote:

Hi
I have a one touch electric can opener (that no longer works).
How it (used to) work:
-Place on a can
-Press switch (momentary)
From there on it turned and cut off the top of the can and stopped
when finished.
I curious about how it worked.
Specfically: How does the momentary switch "latch" or stay closed.
(There aren't any electronic ics).
Batteries then turn gears till the cutting is completed. Somehow a
gear (I think) breaks the circuit and opearations is ended.
The entire circuit is 2 AA batteries (3 volts), a motor, gears and
switches. No electronics or digital logic.
Thanks
BobP
Click to expand...
Probably a "zero seeking" mechanism like a car windshield wiper motor
running in "interval" mode. In that case a momentary (electronic)
contact starts the action then a cam allows a switch to close latching
it on. It stays closed until the wiper reaches its resting/storage
position when the cam opens again shutting off the motor.
--
 
On Sat, 18 Jul 2009 13:35:02 -0400, default <default@defaulter.net>
wrote:

On Sat, 18 Jul 2009 09:55:19 -0700 (PDT), BobP122
JohnNicolet@sympatico.ca> wrote:

Hi
I have a one touch electric can opener (that no longer works).
How it (used to) work:
-Place on a can
-Press switch (momentary)
From there on it turned and cut off the top of the can and stopped
when finished.
I curious about how it worked.
Specfically: How does the momentary switch "latch" or stay closed.
(There aren't any electronic ics).
Batteries then turn gears till the cutting is completed. Somehow a
gear (I think) breaks the circuit and opearations is ended.
The entire circuit is 2 AA batteries (3 volts), a motor, gears and
switches. No electronics or digital logic.
Thanks
BobP

Probably a "zero seeking" mechanism like a car windshield wiper motor
running in "interval" mode. In that case a momentary (electronic)
contact starts the action then a cam allows a switch to close latching
it on. It stays closed until the wiper reaches its resting/storage
position when the cam opens again shutting off the motor.
Click to expand...
---
If it was cam operated, then it wouldn't work on different sizes of
cans.

JF
 
On Sat, 18 Jul 2009 09:55:19 -0700 (PDT), BobP122
<JohnNicolet@sympatico.ca> wrote:

Hi
I have a one touch electric can opener (that no longer works).
How it (used to) work:
-Place on a can
-Press switch (momentary)
From there on it turned and cut off the top of the can and stopped
when finished.
I curious about how it worked.
Specfically: How does the momentary switch "latch" or stay closed.
(There aren't any electronic ics).
Batteries then turn gears till the cutting is completed. Somehow a
gear (I think) breaks the circuit and opearations is ended.
The entire circuit is 2 AA batteries (3 volts), a motor, gears and
switches. No electronics or digital logic.
Thanks
BobP
Click to expand...
Maybe the motor current keeps the switch closed until the torque drops
off. A simple magnetic thing could do that.

John
 
BobP122 wrote:

Hi
I have a one touch electric can opener (that no longer works).
How it (used to) work:
-Place on a can
-Press switch (momentary)
From there on it turned and cut off the top of the can and stopped
when finished.
I curious about how it worked.
Specfically: How does the momentary switch "latch" or stay closed.
(There aren't any electronic ics).
Batteries then turn gears till the cutting is completed. Somehow a
gear (I think) breaks the circuit and opearations is ended.
The entire circuit is 2 AA batteries (3 volts), a motor, gears and
switches. No electronics or digital logic.
Thanks
BobP
Years ago I took one apart, there were no electronics in it.
Click to expand...

What it did was the button would push in a gear that had a
spring behind it to push it back out to unmeshed the gear.

Constant torque would keep the gear pulled in the basket and
also keep a contact closed.

when torque was lost, the gear would pop out..

It's possible the gear is worn out or the switch contact needs a little
adjusting.

This is typical for home counter top types. You could also have a
DC solenoid tied in series with the load that is pulling in a contact
while there is enough current from the load holding the circuit closed.

This also could be integrated in the motor, if that is the case, you
should have a 3 wire motor at a min. The momentary switch simply
supplies power after this internal switch to get it started. The current
load will then pull the contacts to get power from the other wire.
 
On Sat, 18 Jul 2009 13:06:13 -0500, John Fields
<jfields@austininstruments.com> wrote:

On Sat, 18 Jul 2009 13:35:02 -0400, default <default@defaulter.net
wrote:

On Sat, 18 Jul 2009 09:55:19 -0700 (PDT), BobP122
JohnNicolet@sympatico.ca> wrote:

Hi
I have a one touch electric can opener (that no longer works).
How it (used to) work:
-Place on a can
-Press switch (momentary)
From there on it turned and cut off the top of the can and stopped
when finished.
I curious about how it worked.
Specfically: How does the momentary switch "latch" or stay closed.
(There aren't any electronic ics).
Batteries then turn gears till the cutting is completed. Somehow a
gear (I think) breaks the circuit and opearations is ended.
The entire circuit is 2 AA batteries (3 volts), a motor, gears and
switches. No electronics or digital logic.
Thanks
BobP

Probably a "zero seeking" mechanism like a car windshield wiper motor
running in "interval" mode. In that case a momentary (electronic)
contact starts the action then a cam allows a switch to close latching
it on. It stays closed until the wiper reaches its resting/storage
position when the cam opens again shutting off the motor.

---
If it was cam operated, then it wouldn't work on different sizes of
cans.

JF
Click to expand...
You are right.

Motor loading might be one way.
--
 
On Sun, 19 Jul 2009 10:19:09 -0400, default <default@defaulter.net>
wrote:

On Sat, 18 Jul 2009 13:06:13 -0500, John Fields
jfields@austininstruments.com> wrote:

On Sat, 18 Jul 2009 13:35:02 -0400, default <default@defaulter.net
wrote:

On Sat, 18 Jul 2009 09:55:19 -0700 (PDT), BobP122
JohnNicolet@sympatico.ca> wrote:

Hi
I have a one touch electric can opener (that no longer works).
How it (used to) work:
-Place on a can
-Press switch (momentary)
From there on it turned and cut off the top of the can and stopped
when finished.
I curious about how it worked.
Specfically: How does the momentary switch "latch" or stay closed.
(There aren't any electronic ics).
Batteries then turn gears till the cutting is completed. Somehow a
gear (I think) breaks the circuit and opearations is ended.
The entire circuit is 2 AA batteries (3 volts), a motor, gears and
switches. No electronics or digital logic.
Thanks
BobP

Probably a "zero seeking" mechanism like a car windshield wiper motor
running in "interval" mode. In that case a momentary (electronic)
contact starts the action then a cam allows a switch to close latching
it on. It stays closed until the wiper reaches its resting/storage
position when the cam opens again shutting off the motor.

---
If it was cam operated, then it wouldn't work on different sizes of
cans.

JF

You are right.

Motor loading might be one way.
Click to expand...
---
Might be; maybe the OP can post some pictures pf the thing's guts?

JF
 
"BobP122" <JohnNicolet@sympatico.ca> wrote in message
news:407908d7-d433-43c5-a13c-a68882c99ec2@w41g2000yqb.googlegroups.com...
Hi
I have a one touch electric can opener (that no longer works).
How it (used to) work:
-Place on a can
-Press switch (momentary)
From there on it turned and cut off the top of the can and stopped
when finished.
I curious about how it worked.
Specfically: How does the momentary switch "latch" or stay closed.
(There aren't any electronic ics).
Batteries then turn gears till the cutting is completed. Somehow a
gear (I think) breaks the circuit and opearations is ended.
The entire circuit is 2 AA batteries (3 volts), a motor, gears and
switches. No electronics or digital logic.
Thanks
BobP
Click to expand...
Basically it is a very simple minded mechanism that senses the motor torque.
The motor shaft or a gear shaft is free to slide back and forth about a mm
or two and is spring loaded forward. The motor pinion or gear has its gear
teeth cut on an angle so when driving a load the reaction force pushes the
shaft back. A leaf switch (thin phosphor-bronze leafs) make contact when the
shaft pushes back on them thus closing the circuit keeping the motor
running. When the torque eases off, the loading spring pushes the shaft
forward opening the switch. These things are never elaborate or complicated.
 
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