Finding engineering data on shock absorbers

Kinda oddball question, hoping that someone will know.

I'm almost ready to re-hang my driveway gate - we've been surviving with
a roll of chicken wire for way too long - but before it goes on it needs
a shock absorber to keep it from breaking exactly the way it did before.

(It's a scissors gate, about 120 pounds, 18 feet long and it pivots up
and down on one end. It's counterbalanced on springs, but when an
enthusiastic kid closes it the crash is a thing to behold -- and a thing
to break welds.)

I don't want to cut and try a bazillion different things, and I'm an
engineer so I have the delusion that I can design things from first
principals.

Is there any place I can find engineering data on vehicle shock
absorbers? Not "buy this here shock for that there truck, and get 'em
heavy duty if you want to put two cows in there", but real honest-to-gosh
tables with numbers and other useful things for folks who are blatantly
mis-applying a vehicle shock absorber.

At the least I need things like stroke and mounting data, but something
that gives the damping rate of the thing would be uber-cool. In the
absence of damping rate a vehicle weight / shock chart would be useful,
but it'd be a distant second best.

Stroke and mounting data are obvious (if I can match what's in my truck
I'll be quite happy), but if I had the force vs. velocity curves for a
number of different shocks then I'd know from the get-go if I'm in the
right ball park, and where to put my pivot points, and that sort of thing.

--
www.wescottdesign.com

On Feb 2, 7:02*pm, Tim Wescott > wrote:
> Kinda oddball question, hoping that someone will know.
>
> I'm almost ready to re-hang my driveway gate - we've been surviving with
> a roll of chicken wire for way too long - but before it goes on it needs
> a shock absorber to keep it from breaking exactly the way it did before.
>
> (It's a scissors gate, about 120 pounds, 18 feet long and it pivots up
> and down on one end. *It's counterbalanced on springs, but when an
> enthusiastic kid closes it the crash is a thing to behold -- and a thing
> to break welds.)
>
> I don't want to cut and try a bazillion different things, and I'm an
> engineer so I have the delusion that I can design things from first
> principals.
>
> Is there any place I can find engineering data on vehicle shock
> absorbers? *Not "buy this here shock for that there truck, and get 'em
> heavy duty if you want to put two cows in there", but real honest-to-gosh
> tables with numbers and other useful things for folks who are blatantly
> mis-applying a vehicle shock absorber.
>
> At the least I need things like stroke and mounting data, but something
> that gives the damping rate of the thing would be uber-cool. *In the
> absence of damping rate a vehicle weight / shock chart would be useful,
> but it'd be a distant second best.
>
> Stroke and mounting data are obvious (if I can match what's in my truck
> I'll be quite happy), but if I had the force vs. velocity curves for a
> number of different shocks then I'd know from the get-go if I'm in the
> right ball park, and where to put my pivot points, and that sort of thing..
>
> --www.wescottdesign.com

Googling "shock dampeners" lead to this:
http://www.taylordevices.com/pdf/M-s...ifications.pdf
Perhaps instead of a fixed device you could use an adjustable heavy-
duty door closer, like for a fire door.

jsw

On Tue, 02 Feb 2010 16:22:43 -0800, Jim Wilkins wrote:

> On Feb 2, 7:02Â*pm, Tim Wescott > wrote:
>> Kinda oddball question, hoping that someone will know.
>>
>> I'm almost ready to re-hang my driveway gate - we've been surviving
>> with a roll of chicken wire for way too long - but before it goes on it
>> needs a shock absorber to keep it from breaking exactly the way it did
>> before.
>>
>> (It's a scissors gate, about 120 pounds, 18 feet long and it pivots up
>> and down on one end. Â*It's counterbalanced on springs, but when an
>> enthusiastic kid closes it the crash is a thing to behold -- and a
>> thing to break welds.)
>>
>> I don't want to cut and try a bazillion different things, and I'm an
>> engineer so I have the delusion that I can design things from first
>> principals.
>>
>> Is there any place I can find engineering data on vehicle shock
>> absorbers? Â*Not "buy this here shock for that there truck, and get 'em
>> heavy duty if you want to put two cows in there", but real
>> honest-to-gosh tables with numbers and other useful things for folks
>> who are blatantly mis-applying a vehicle shock absorber.
>>
>> At the least I need things like stroke and mounting data, but something
>> that gives the damping rate of the thing would be uber-cool. Â*In the
>> absence of damping rate a vehicle weight / shock chart would be useful,
>> but it'd be a distant second best.
>>
>> Stroke and mounting data are obvious (if I can match what's in my truck
>> I'll be quite happy), but if I had the force vs. velocity curves for a
>> number of different shocks then I'd know from the get-go if I'm in the
>> right ball park, and where to put my pivot points, and that sort of
>> thing.
>>
>> --www.wescottdesign.com
>
> Googling "shock dampeners" lead to this:
> http://www.taylordevices.com/pdf/M-s...ifications.pdf Perhaps
> instead of a fixed device you could use an adjustable heavy- duty door
> closer, like for a fire door.
>
> jsw

It'd have to be a damn heavy fire door.

I figure that -- assuming that automotive shocks are close enough -- I'll
get an adjustable one and tinker with it. It still needs to be close,
though, or I'll be repeating a lot of effort.

--
www.wescottdesign.com

Tim Wescott wrote:
> Kinda oddball question, hoping that someone will know.
>
> I'm almost ready to re-hang my driveway gate - we've been surviving with
> a roll of chicken wire for way too long - but before it goes on it needs
> a shock absorber to keep it from breaking exactly the way it did before.
>
> (It's a scissors gate, about 120 pounds, 18 feet long and it pivots up
> and down on one end. It's counterbalanced on springs, but when an
> enthusiastic kid closes it the crash is a thing to behold -- and a thing
> to break welds.)
>
> I don't want to cut and try a bazillion different things, and I'm an
> engineer so I have the delusion that I can design things from first
> principals.
>
> Is there any place I can find engineering data on vehicle shock
> absorbers? Not "buy this here shock for that there truck, and get 'em
> heavy duty if you want to put two cows in there", but real honest-to-gosh
> tables with numbers and other useful things for folks who are blatantly
> mis-applying a vehicle shock absorber.
>
> At the least I need things like stroke and mounting data, but something
> that gives the damping rate of the thing would be uber-cool. In the
> absence of damping rate a vehicle weight / shock chart would be useful,
> but it'd be a distant second best.
>
> Stroke and mounting data are obvious (if I can match what's in my truck
> I'll be quite happy), but if I had the force vs. velocity curves for a
> number of different shocks then I'd know from the get-go if I'm in the
> right ball park, and where to put my pivot points, and that sort of thing.
>
http://files.smcetech.com/pdf/newpro...20-200A%29.pdf

On Tue, 02 Feb 2010 19:32:00 -0500, Steve Austin wrote:

> Tim Wescott wrote:
>> Kinda oddball question, hoping that someone will know.
>>
>> I'm almost ready to re-hang my driveway gate - we've been surviving
>> with a roll of chicken wire for way too long - but before it goes on it
>> needs a shock absorber to keep it from breaking exactly the way it did
>> before.
>>
>> (It's a scissors gate, about 120 pounds, 18 feet long and it pivots up
>> and down on one end. It's counterbalanced on springs, but when an
>> enthusiastic kid closes it the crash is a thing to behold -- and a
>> thing to break welds.)
>>
>> I don't want to cut and try a bazillion different things, and I'm an
>> engineer so I have the delusion that I can design things from first
>> principals.
>>
>> Is there any place I can find engineering data on vehicle shock
>> absorbers? Not "buy this here shock for that there truck, and get 'em
>> heavy duty if you want to put two cows in there", but real
>> honest-to-gosh tables with numbers and other useful things for folks
>> who are blatantly mis-applying a vehicle shock absorber.
>>
>> At the least I need things like stroke and mounting data, but something
>> that gives the damping rate of the thing would be uber-cool. In the
>> absence of damping rate a vehicle weight / shock chart would be useful,
>> but it'd be a distant second best.
>>
>> Stroke and mounting data are obvious (if I can match what's in my truck
>> I'll be quite happy), but if I had the force vs. velocity curves for a
>> number of different shocks then I'd know from the get-go if I'm in the
>> right ball park, and where to put my pivot points, and that sort of
>> thing.
>>
> http://files.smcetech.com/pdf/newpro...20Absorber%20%
28ES20-200A%29.pdf

There's a difference in nomenclature between industrial and American
automotive usage.

In industrial usage a "shock absorber" is a thingie that, when you run
something heavy into it, absorbs the shock. That's what you've sent me a
data sheet for. It's not what I need.

In American automotive usage a "shock absorber" is a thingie that, when
you push or pull on it, resists motion with (usually) an increasing
resistance force for increasing velocity. In industrial and British
automotive usage such a thingie is a "damper". That's what I need.

I'd love to have enough $$ to get an industrial damper, and the contacts
to be able to easily buy more when the first one wears out (or if it
turns out that I've mis-specified it). But I can swing down to the
corner auto parts store and get something that may well be what I need,
at an affordable price, on a Saturday, in less than an hour. So if I can
use that instead, that's what I want.

--
www.wescottdesign.com

On Tue, 2 Feb 2010 16:22:43 -0800 (PST), Jim Wilkins
> wrote:

>On Feb 2, 7:02Â*pm, Tim Wescott > wrote:
>> Kinda oddball question, hoping that someone will know.
>>
>> I'm almost ready to re-hang my driveway gate - we've been surviving with
>> a roll of chicken wire for way too long - but before it goes on it needs
>> a shock absorber to keep it from breaking exactly the way it did before.
>>
>> (It's a scissors gate, about 120 pounds, 18 feet long and it pivots up
>> and down on one end. Â*It's counterbalanced on springs, but when an
>> enthusiastic kid closes it the crash is a thing to behold -- and a thing
>> to break welds.)
>>
>> I don't want to cut and try a bazillion different things, and I'm an
>> engineer so I have the delusion that I can design things from first
>> principals.
>>
>> Is there any place I can find engineering data on vehicle shock
>> absorbers? Â*Not "buy this here shock for that there truck, and get 'em
>> heavy duty if you want to put two cows in there", but real honest-to-gosh
>> tables with numbers and other useful things for folks who are blatantly
>> mis-applying a vehicle shock absorber.
>>
>> At the least I need things like stroke and mounting data, but something
>> that gives the damping rate of the thing would be uber-cool. Â*In the
>> absence of damping rate a vehicle weight / shock chart would be useful,
>> but it'd be a distant second best.
>>
>> Stroke and mounting data are obvious (if I can match what's in my truck
>> I'll be quite happy), but if I had the force vs. velocity curves for a
>> number of different shocks then I'd know from the get-go if I'm in the
>> right ball park, and where to put my pivot points, and that sort of thing.
>>
>> --www.wescottdesign.com
>
>Googling "shock dampeners" lead to this:
>http://www.taylordevices.com/pdf/M-s...ifications.pdf
>Perhaps instead of a fixed device you could use an adjustable heavy-
>duty door closer, like for a fire door.
>
>jsw
Check Koni and other "race/performance" shocks - they usually have
jounce and rebound valving specs and are adjustable.

Tim Wescott writes:

> At the least I need things like stroke and mounting data, ...

Sir, this is a metalworking group. You do not need such data, because you
will sand-cast the parts in your backyard foundry and finish them on a
lathe in your basement, to whatever specs you like.

I think a gas strut would work out better. It would provide a
constant resistance on the way down. There are many lengths and
ratings.

--
______________________________
Keep the whole world singing . . . .
DanG (remove the sevens)




"Tim Wescott" > wrote in message
...
> Kinda oddball question, hoping that someone will know.
>
> I'm almost ready to re-hang my driveway gate - we've been
> surviving with
> a roll of chicken wire for way too long - but before it goes on
> it needs
> a shock absorber to keep it from breaking exactly the way it did
> before.
>
> (It's a scissors gate, about 120 pounds, 18 feet long and it
> pivots up
> and down on one end. It's counterbalanced on springs, but when
> an
> enthusiastic kid closes it the crash is a thing to behold -- and
> a thing
> to break welds.)
>
> I don't want to cut and try a bazillion different things, and
> I'm an
> engineer so I have the delusion that I can design things from
> first
> principals.
>
> Is there any place I can find engineering data on vehicle shock
> absorbers? Not "buy this here shock for that there truck, and
> get 'em
> heavy duty if you want to put two cows in there", but real
> honest-to-gosh
> tables with numbers and other useful things for folks who are
> blatantly
> mis-applying a vehicle shock absorber.
>
> At the least I need things like stroke and mounting data, but
> something
> that gives the damping rate of the thing would be uber-cool. In
> the
> absence of damping rate a vehicle weight / shock chart would be
> useful,
> but it'd be a distant second best.
>
> Stroke and mounting data are obvious (if I can match what's in
> my truck
> I'll be quite happy), but if I had the force vs. velocity curves
> for a
> number of different shocks then I'd know from the get-go if I'm
> in the
> right ball park, and where to put my pivot points, and that sort
> of thing.
>
> --
> www.wescottdesign.com