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geekhack Community => Keyboards => Topic started by: dw_junon on Mon, 02 February 2009, 16:35:46

Title: The Harris Patent and The Coleman Patent
Post by: dw_junon on Mon, 02 February 2009, 16:35:46

I don't think I've seen this come up before here, so here goes...

Thanks I suppose to Mr Ermita, it seems that US Patent #4118611 Aug 30, 1977 (http://www.google.com/patents?id=WpAwAAAAEBAJ&printsec=abstract&zoom=4) by Richard Hunter Harris for the "Buckling spring torsional snap actuator" is pretty familiar around here.

It's immediately obvious (at least to us lot) that it refers to keyboard switches, though there is an earlier Harris patent (http://www.google.com/patents?id=1gs1AAAAEBAJ&printsec=abstract&zoom=4&dq=3699296) from '71, referenced in the '77 patent, which appears to be the initiation of using a spring like this, developing the idea from snap action switches.  He also refers to a '71 Holzer patent with a very interesting system (http://www.google.com/patents?id=pjk6AAAAEBAJ&printsec=abstract&zoom=4), but I digress.

However, The Harris Patent of '77 refers to "Individual electrical contacts... shown mounted on a circuit board or other similar non-conductive substrate" and furthermore states that the contacts "constitute plates in a capacitive switching system".

This sounds distinctly like Model F technology.

There is a later patent by Edwin T. Coleman, III which references The Harris Patent, for a "Rocking switch actuator for a low force membrane contact switch (http://www.google.com/patents?id=mBc6AAAAEBAJ&printsec=abstract&zoom=4)", filed in October '83, issued July '85, which describes "a pivoting rocking actuator"  with a "membrane contact switch assembly".  The membrane assembly "includes an upper layer... of an electrically insulating material, an intermediate layer... of an electrically insulating material, and a lower layer... of an electrically insulating material."

Coleman makes clear that the new "invention is an improvement of the aforesaid Harris patent in that the cost of the present invention is substantially less, approximately half, than the apparatus of the aforesaid Harris patent.".  This corresponds to the view presented by DeFosse et al. in "Development of a membrane switch-type full-travel tactile keyboard (http://www.research.ibm.com/journal/rd/295/ibmrd2905G.pdf)" in the IBM Research Journal in September '85, which opens with opens with the words "To reduce cost in the area of keyboards...".

In other words, I'm pretty sure that this Coleman patent is a better reference for the Model M than The Harris Patent.

Note that while Coleman refers to a "low force" switch, the key travel/key force plots are remarkably similar (click for the entries at Google Patents):

(http://www.9999hp.net/keyboard/IBM/4118611_Harris_travel-force.png) (http://www.google.com/patents?id=WpAwAAAAEBAJ&printsec=abstract&zoom=4#PPA3,M1)(http://www.9999hp.net/keyboard/IBM/4528431_Coleman_travel-force.png) (http://www.google.com/patents?id=mBc6AAAAEBAJ&printsec=abstract&zoom=4#PPA6,M1)

Title: The Harris Patent and The Coleman Patent
Post by: Chloe on Mon, 02 February 2009, 17:35:54

Good find. The Harris patent 4118611 does sound like Model F.

Quote from:

In U.S. Pat. No. 4,118,611 to Harris, there is shown a pivoting switch actuator using a buckling compression spring to move the actuator in response to depression of a key whereby the actuator causes closing and opening of a switch through changing the capacitance between contacts with which the actuator cooperates. The actuator of the aforesaid Harris patent pivots about a single pivot point when a key is depressed.

The rocker actuator in Coleman patent 4528431 (Fig. 8) looks just like the one in the 5576-A01. I assume this is the same as Model M:
http://park16.wakwak.com/~ex4/kb/tech_bucklingspring_e.htm

Title: The Harris Patent and The Coleman Patent
Post by: wellington1869 on Mon, 02 February 2009, 17:55:44

I'd like to put that graph on a t-shirt :)

Title: The Harris Patent and The Coleman Patent
Post by: dw_junon on Mon, 02 February 2009, 20:01:59

Quote from: Chloe;20634

Good find. The Harris patent 4118611 does sound like Model F.

Quote

In U.S. Pat. No. 4,118,611 to Harris, there is shown a pivoting switch actuator using a buckling compression spring to move the actuator in response to depression of a key whereby the actuator causes closing and opening of a switch through changing the capacitance between contacts with which the actuator cooperates. The actuator of the aforesaid Harris patent pivots about a single pivot point when a key is depressed.

The rocker actuator in Coleman patent 4528431 (Fig. 8) looks just like the one in the 5576-A01. I assume this is the same as Model M:
http://park16.wakwak.com/~ex4/kb/tech_bucklingspring_e.htm

Ah, interesting; thanks.  Not an exact replica perhaps, but surely very much the same idea.  There's not really any reason why those should be identical to the original drawing anyway, particularly given that this was redesigned in Japan(?).

(http://www.9999hp.net/keyboard/IBM/4528431_Coleman_rocker_actuator.png) (http://www.google.com/patents?id=mBc6AAAAEBAJ&printsec=abstract&zoom=4#PPA5,M1) (http://park16.wakwak.com/~ex4/kb/tech/bucklingspring1_b.jpg) (http://park16.wakwak.com/~ex4/kb/tech_bucklingspring_e.htm) (http://park16.wakwak.com/~ex4/kb/tech/bucklingspring1_a.jpg) (http://park16.wakwak.com/~ex4/kb/tech_bucklingspring_e.htm)

Quote from: wellington1869;20638

I'd like to put that graph on a t-shirt :)

heh, yeah.  In my case, I imagine I'd just scare people, but that could be fun in itself, perhaps.

Title: The Harris Patent and The Coleman Patent
Post by: wellington1869 on Mon, 02 February 2009, 21:30:03

so thats the actual rocker switch, huh? Interesting. Its much bigger than I expected.

Title: The Harris Patent and The Coleman Patent
Post by: dw_junon on Tue, 03 February 2009, 06:50:45

Quote from: wellington1869;20663

so thats the actual rocker switch, huh? Interesting. Its much bigger than I expected.

Well, they're from the Japanese Type 5576 keyboards, submodels 003 and A01, which use individual detachable modules for each key (click the photos).

Ah, there is a photo on 3m3718.com's mpr0n page of some from a '401:

http://www.3m3718.com/imx/keyboard/modelm/rockers.jpg

I'm not even going to dare to try to display it in-line; I suspect shenanigans.  So paste into something unlikely, like Links maybe, and see if you can manage to get it to display.  If that doesn't even work, just go to http://www.3m3718.com/ on the right day of the week and click Model M, and then the deconstructive bullet point.

Perhaps there is an image elsewhere on this forum?...

Title: The Harris Patent and The Coleman Patent
Post by: bhtooefr on Tue, 03 February 2009, 09:36:17

Transloaded to my photobucket:

(http://i539.photobucket.com/albums/ff354/bhtooefr/rockers.jpg)

Title: The Harris Patent and The Coleman Patent
Post by: wellington1869 on Tue, 03 February 2009, 13:13:07

thanks bht.  they look about the same size to me though. the rocker switch almost looks wider than the actual key!

Title: The Harris Patent and The Coleman Patent
Post by: dw_junon on Tue, 03 February 2009, 19:51:41

Quote from: bhtooefr;20707

Transloaded to my photobucket:

Show Image

(http://i539.photobucket.com/albums/ff354/bhtooefr/rockers.jpg)

Ah, super.  Thanks for that.

While it is harder to see the detail in that picture, I reckon they do resemble that figure 8 from the Coleman patent pretty near.  More so than the 5576 rockers, anyway.

Title: The Harris Patent and The Coleman Patent
Post by: sandy55 on Wed, 04 February 2009, 05:06:18

some pictures of rocking hammer

comparison; bottom image of A01 and M
(http://geekhack.org/attachment.php?attachmentid=693&stc=1&d=1233745880)

comparison; upper image of A01 and M
(http://geekhack.org/attachment.php?attachmentid=694&stc=1&d=1233745919)

upper image of M's rocker
(http://geekhack.org/attachment.php?attachmentid=698&stc=1&d=1233746407)

bottom image of M's rocker
(http://geekhack.org/attachment.php?attachmentid=696&stc=1&d=1233745947)

upstanding post
(http://geekhack.org/attachment.php?attachmentid=697&stc=1&d=1233745965)

Title: The Harris Patent and The Coleman Patent
Post by: dw_junon on Wed, 04 February 2009, 06:28:34

Quote from: sandy55;20771

some pictures of rocking hammer

Fantastic pictures, Sandy!  Thank you!

I must say, I did not realise the M rocker was so much wider than the A01's from the earlier pictures.

Title: The Harris Patent and The Coleman Patent
Post by: wellington1869 on Wed, 04 February 2009, 12:10:34

great pics

Title: The Harris Patent and The Coleman Patent
Post by: Chloe on Fri, 06 February 2009, 00:05:31

Here are some pictures of the capacitive rocker actuator:
http://sandy55.fc2web.com/keyboard/model_m_trivia.html#5640991