is there no end to the detail that's needed??
okaay so i started on the screen edge, which (surprise) turned out to need to be thicker than anticipated. increasing the thickness by 2mm had a knock-on effect because, naturally, the base end depth has to be increased to match.
then i began work on the friction hinge for the screen lid, so that it will remain upright. you'd think it would be easy to create an interlock between two pieces 8mm in diameter that looks aesthetic and is strong enough, but nooo i can tell you it damn well isn't :)
now i am onto one of the final pieces of the puzzle: creating a lid lock. this needs to be spring-loaded (ball-point biro pen spring, cut into 1/4s 7mm long) and i am kinda amazed at how much detail is needed in such a small space. the clasp is 10mm x 9mm x 8mm but requires a 5mm diameter hole in the centre (for the spring)... we'll have to see how it works out.
l.
On 07/23/15 17:53, Luke Kenneth Casson Leighton wrote:
is there no end to the detail that's needed??
okaay so i started on the screen edge, which (surprise) turned out to need to be thicker than anticipated. increasing the thickness by 2mm had a knock-on effect because, naturally, the base end depth has to be increased to match.
then i began work on the friction hinge for the screen lid, so that it will remain upright. you'd think it would be easy to create an interlock between two pieces 8mm in diameter that looks aesthetic and is strong enough, but nooo i can tell you it damn well isn't :)
now i am onto one of the final pieces of the puzzle: creating a lid lock. this needs to be spring-loaded (ball-point biro pen spring, cut into 1/4s 7mm long) and i am kinda amazed at how much detail is needed in such a small space. the clasp is 10mm x 9mm x 8mm but requires a 5mm diameter hole in the centre (for the spring)... we'll have to see how it works out.
l.
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most laptops these days have dispensed with a lid lock. imho this is a good idea. so i respectfully suggest that you dispense with it.
On Thu, Jul 23, 2015 at 8:14 PM, Simon Kenyon simon@koala.ie wrote:
most laptops these days have dispensed with a lid lock. imho this is a good idea. so i respectfully suggest that you dispense with it.
yeah i thought about how to achieve a lockless lid, and with the available materials i concluded that it would not be practical right now: notably, it would require custom-machined metal parts or to source parts and to redesign the laptop casework based around those parts.
(a) sourcing parts takes time (b) custom-machining metal parts costs money (c) chances are high that sourced existing parts would not fit the unusual design (d) even using high-strength magnets there is no available space to fit the magnets into the lid without weakening the plastic lid surround to the point of impracticality.
so, logically, with all other options eliminated for various reasons, a lid lock is the sole remaining option.
's'the way it goes, simon.
l.
@Luke -- how about having hinges with a little bit of a spring-click mechanism? That way you wouldn't have to put anything in the lid itself. I've seen hinges like that (for doors tho) at the hardware store.
On Thu, Jul 23, 2015 at 8:32 PM, Christopher Havel laserhawk64@gmail.com wrote:
@Luke -- how about having hinges with a little bit of a spring-click mechanism?
that's where the machined metal would be needed. the screen weighs 450g, and its depth is around 21cm. 1/2 way point is 10cm, so we're looking at .45*10/10 = .45 Nm of torque.... on an 8mm diameter hinge, which means average .45/.02 = 22N of force exerted.
That way you wouldn't have to put anything in the lid itself. I've seen hinges like that (for doors tho) at the hardware store.
where would one obtain custom-made 8mm diameter spring-click hinges without requiring paying machining fees or to place an order with a MOQ beyond realistic levels?
over the past 4 years we've been down this road before several times, and i've decided i'm not going to waste time and effort on it.
so i've decided i'm taking the path of least resistance, knowing that once that path has been successful any changes may be accommodated *afterwards*, when there is finance available from steady sustainable income.
l.
On Thu, Jul 23, 2015 at 8:46 PM, Christopher Havel laserhawk64@gmail.com wrote:
Oh well, it was just an idea... apparently not a good one, though.
it's a good one.... *if* there's a budget for - and time to source - the part.
l.
Ah. In that case...
Small rectangular notch in one side of each hinge barrel (I think barrel's the term... the part that goes around the pin). Little teeny ball bearing (like 2-3mm dia, you know, the sort of stuff you find in a BB gun) with a stiff spring behind it (either a coil spring, or a leaf spring with a long lip and a dimple to hold the BB). One on each side ought to do it. You can even have the notch on the same side for both hinges, if there's room... if not, I say notch both sides of the hinge so it'll work in either direction.
Again, just a thought. File it somewhere if ya can't use it now... never know when it'll come in handy ;)
On Thu, Jul 23, 2015 at 8:58 PM, Christopher Havel laserhawk64@gmail.com wrote:
Ah. In that case...
Small rectangular notch in one side of each hinge barrel (I think barrel's the term... the part that goes around the pin). Little teeny ball bearing (like 2-3mm dia, you know, the sort of stuff you find in a BB gun) with a stiff spring behind it (either a coil spring, or a leaf spring with a long lip and a dimple to hold the BB). One on each side ought to do it. You can even have the notch on the same side for both hinges, if there's room... if not, I say notch both sides of the hinge so it'll work in either direction.
yeahhh you remember i said there's an 8mm barrel to work with? that's the outer dimensions. printing a part to fit in there needs to be a maximum of a 37mm radius, and there's a 20mm diameter bolt down the middle as well.
but the accuracy of the printer is, when creating parts, esp. complex ones, limited to about 1.5mm *if that*.
so there's no way i would be able to fit even a 1.5mm diameter ball bearing inside... and still have it be strong enough. the only way i'm confident about what i've created with the friction hinge that i've designed is that it's reasonably chunky. when i made things too thin (1.5mm or below) they just... broke off.
no, what i considered reasonable would be to have a D-shaped ring which you push-fit onto one end of the friction hinge, then house a simple flat spring that bends against the D.
when the spring hits the flat of the D, that's when it helps keep the lid closed.
when it's bent, it helps act as a friction hinge.
.... but even just sourcing steel flat springs and D-shaped rings i just... i can't be having with it. i've had enough. really. i want this done, and i want it out the door, no delays dealing with suppliers or with creating experimental prototype mechanical custom-made custom-machined parts.
i have a 3d printer, i have some 2mm threaded bar, i have some M2 8mm screws, and i have a spring from a biro. once product is sold, *then* we can get fancy.
l.
Luke Kenneth Casson Leighton lkcl@lkcl.net writes:
is there no end to the detail that's needed??
okaay so i started on the screen edge, which (surprise) turned out to need to be thicker than anticipated. increasing the thickness by 2mm had a knock-on effect because, naturally, the base end depth has to be increased to match.
then i began work on the friction hinge for the screen lid, so that it will remain upright. you'd think it would be easy to create an
Nope ;-)
interlock between two pieces 8mm in diameter that looks aesthetic and is strong enough, but nooo i can tell you it damn well isn't :)
now i am onto one of the final pieces of the puzzle: creating a lid lock. this needs to be spring-loaded (ball-point biro pen spring, cut into 1/4s 7mm long) and i am kinda amazed at how much detail is needed in such a small space. the clasp is 10mm x 9mm x 8mm but requires a 5mm diameter hole in the centre (for the spring)... we'll have to see how it works out.
You could just not bother with a lock.
I have a Lenovo Thinkpad X230, and it has no lock on the lid.
There is a slight impression that the lid snaps shut when almost closed, but it's not clear if that's really the case.
You could alternatively do some sort of rotating thing on the corners, like the OLPC's wifi arials.
Cheers, Phil.
On Thu, Jul 23, 2015 at 9:03 PM, Philip Hands phil@hands.com wrote:
then i began work on the friction hinge for the screen lid, so that it will remain upright. you'd think it would be easy to create an
Nope ;-)
you'd be right!
You could just not bother with a lock.
yehhh the friction hinge isn't accurate enough, there's a few degrees of play and that means the lid will be flapping by about... at least 1 maybe even 2cm once wear sets in.
I have a Lenovo Thinkpad X230, and it has no lock on the lid.
There is a slight impression that the lid snaps shut when almost closed, but it's not clear if that's really the case.
You could alternatively do some sort of rotating thing on the corners, like the OLPC's wifi arials.
ah! of course! nice idea... i don't hold out much hope (the screen edge plastic is only 2.5mm thick as it is) - i'll try to drop it into my tiny subconscious and see what happens over the next couple of days.
l.
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