Help on not using a magnet on reed switch

[osomemac]

I had design a device that involve a mini circuit that use a reed switch. After all is said and done, I am told due to patent law I CANNOT use a magnet as a actuator. I need a THING that is reasonably cheap that can activate a reed switch. The current design call for a 0.5" diameter by 0.125" thick button magnet. Anyone who have an idea that can save me would be sincerely appreciated. I need all the help I can get.

 

[ScottyUK]

A coil carrying current?


----------------------------------

Sometimes I only open my mouth to swap feet...

 

[osomemac]

Not a bad idea, except I just reread, the patent, it said magnetic field. So ned something different. How about RF, SHOCK, etc.

 

[itsmoked]

Reed switches use magnetic fields. There are probably about 1,000,000 products that use a magnet and a reed switch! How could this cause you problems.. Who ever is complaining about this should maybe look into it further!

Lets be rational - how could all the reed switch companies sell reed switches if there was some patent blocking their use?!?

Keith Cress
Flamin Systems, Inc.-

http://www.flaminsystems.com

 

[osomemac]

That is what I thougth origially, Keith. But I am being given court paper for I also used a reed switch and a magent. All is different. Electrontics approach, size, shape and weight. But the claim said he patented the device using reed and magent thus I violate his patent. My device is more reliable, cheaper to built and do the job better. BUT I am not a lawyer and thus I try to find an engineering solution so claim "7" cannot be off my pack.

 

[zeitghost]

I'm gonna patent the wheel...

 

[IRstuff]

The hallmark of a patentable device is precisely an improvement over the prior art.

Your job is to prove that you have an improvement. Either you have no improvement or you have an idiot for a lawyer. You've either done a bad job at demonstrating an improvement or you need to get a new lawyer

TTFN

 

[Comcokid]

Zeitghose - Just to show how inept the patent office is, a lawyer recently patented a wheel![/i]

Osomemac - Maybe, you could use a spinning magent or AC solenoid, file a new patent, and indicate that he didn't patent the use of an alternating magentic field.

Or, you could use a normally closed reed switch from which you activate by removing a magnet, and claim you device uses the absence of a magnetic field.

Or use another kind of remote switch. Tilt switch? Photocell? Some kind of electric field activation? Tacheons?

OK, maybe that last one was a bit too Star Trek.

 

[IRstuff]

I don't see that you've given sufficient information to determine the criticality of the reed switch in your invention.

Nonetheless, the infringement does not exist in practice, since your usage requires buying a part from a supplier who has license to manufacture it. Otherwise, you'd be infringing on the patent simply by buying it off the shelf and using it in a normal circuit. You need to get more clarification from your lawyer.

TTFN

 

[OperaHouse]

Just to be fair..... If I invent a better mouse trap for you, shouldn't you be paying me? You presently have a "mini circuit." That could be expanded up to use capacitance or light to sense the position. Or are you actually using the magnetic field created by the actuator?

 

[osomemac]

Hi ALL,

thanks for the ideas. My lawyer said I need to find technical help from EE or sort indication that in my device's operation, a EE would indded use a reed switch. (The one who is skill at the art would consinder it obvious) which would make his patent claim 7 invalid. So, may I ask the "Experts" here the following:

If you are asked to switch a decive on/off when passing a specific point at 300 feet per second. The device is self contained, powered, and cannot be physically touched. There is a 3/4" gap between the device and specific point of the stationary platform. What would a perosn who is skill in the art of EE use to achieve this.

Regards and think you all in advice of your EXPERT opinoin.

 

[IRstuff]

A 3/4" gap seems a bit much for a typical reed switch in any case:

http://en.wikipedia.org/wiki/Reed_switch

although alarm switches can go past 3/4"

http://www.nteinc.com/switches/pdf/magnetic_alarm.pdf

But, as an engineer, you can simply run through all the possible non-contact ways of actuating a switch:

acoustic
magnetic - reed
electro-magnetic inductive
RF
photonic - light, laser

So, it's completely unclear why your lawyer is saying you wouldn't use reed switch. Why is this particular embodiment and none other a problem?

TTFN

 

[osomemac]

Hi IRStuff,

Thank you for your advice. The reason the reed switch was chose is due to physical, weight and power. The device ideal weight inclduing the battery should not exceed 20 grain (1 grain = 1/700 lbs). My next upcoming device shuold weight only 15.5 grain. The device have to function from -15F to 115F. The widith of the device should not exceed 5 mm. Length is not that critical, but I have make mine under 37 mm. It is contained inside high strain carbon fiber tubing. It also have to function in an environemnt that sound is not permitted. Thus acoustic, photonic, light are out of question.

Regards

 

[IRstuff]

Dunno, depends on the light. There are photocouplers that use >800 nm wavelengths, which are not visible.

TTFN

 

[osomemac]

ITSStuff. Please excuse my lack of knowledge. I believe that no light can pass through high strain carbon fiber tubing with 1-3 mm thick wall, with which where the device is house in. But thank you for our help and ideas. I am sorry that I am not able to disclose more detail of the device and pleaase forgive me for not stating clearly that the carbon fiber is a tubing that is 1-3 mm think.

Regards

 

[OperaHouse]

More comments from the Peanut Gallery...... At first I thought this was a cheap toy or novelty. 300ft/sec is about 95 mph. That gives you a pulse of .0003 seconds per linear sensing inch. Pretty fast for a reed switch. Then you are going to do this from one inch away! Add to that, it must be under a half ounce. This seems like a a fairly exotic application. I think you need a little more than free advice. And what industry uses grains?

 

[osomemac]

Hi Operahouse,

This is not a toy and it is a very high demand application. The retail price of this device is about $15.00 each.

Regards

 

[IRstuff]

Imagination is running wild here.

Given the data so far, the only issue might be that the reed switch might not have sufficient time to close before it passes the magnet, unless the magnet is rather large. A 1-inch magnet is passed at 300 ft/s only in under 0.3 ms. That appears to be close to the minimum closure time of most relays:

http://www.hascorelays.com/oki_reed_switches.asp

It's also unclear how you intend to keep the switch oriented correctly. If the switch is rotated 180º, the swithc will not work. There is also a question of switch bounce as well.

Since we're talking design sheet concepts, I would recommend a Hall Effect switch as an alternate. They can be gotten in bipolar forms:

http://www.melexis.com/prodfiles/0004817_0004817_US2881_rev012.pdf

which means that rotation is less of an issue, but not eliminated, although one could imagine placing two of the oriented 180º apart, or two magnets can be used.


Their switching times are under a 1 microsecond, since they're ideal for motor indexing and speed measurement applications. There's no switch bounce. They are substantially more sensitive than a reed switch, as there is no physical mass to move with the magnetic field. They can be specified for -40ºC to +150ºC operation. They are also more g-shock insensitive. Package size is 2.75 mm x 2.9 mm x 1.1 mm.

So, I would vote for a HE switch over a reed switch.



TTFN

 

[osomemac]

IRStuff,

It is wonderful idea of using a He Switch. I thank you for introduce me to this wonderful device. This may be exactly what I am looking for.

 

[IRstuff]

The other advantage of the HE switch is that the magnet can be smaller, which decreases the weight on the fixed platform.

I assume that the 300 ft/s was a placeholder? The application that comse to mind varies from about 250 ft/s to about 350 ft/s. The cost of your product appears to be about 10% of the cost of what it's installed on?

I assume that there is already some sort of manual on/off switch already? And the desire is to use the magnetic switch to turn on some sort of locator beacon? I couldn't find anything similar on the internet, but I might not have gotten the search terms correct.

So, I guessing that a competitor is suing you for patent infringement and you're attempting to counter their patent claim based on obviousness?

TTFN