Was wondering if some of the much smarter and more engineering and mechanically inclined members here might be able to help me, or give me some insight, on how this is being sprung. ???
(https://www.finescalerr.com/smf/proxy.php?request=http%3A%2F%2Fhome.earthlink.net%2F%7Erbadesign%2FSuspension.jpg&hash=fe18d07f3d18d49d0cec5c0b9aa473f9fab91513)
Basically what you are seeing as a lower box containing and electric drive unit, running on 600mm gauge track, with a third rail of track being used for power pick-up. The upper platform consists of a simple angle frame, upon which the superstructure is then mounted (the superstructure carries only one person, and the unit is not controlled by the person...so no connections other than the 4 sprung points).
Basically due to the purpose of this unit, the spring action needs to be quite active/responsive (note the compression between the platform and drive box from front to rear). The 4 sprung points are most likely the only contact and mounting points for the superstructure.
Time period for this would be c.1914-16
At #2 first I thought maybe coil springs...but when I enlarged the pic to this size, it began to look more like a flat wound type of spring (don't know the technical name)...but then I noticed the odd shadow bump/offset at area #3...which looks like some kind of vertical cylindrical housing protruding from the drive box....this led me to wonder if instead of a spring #2 might be some kind of shock absorber type set-up.
And lastly, item #1 seems to be some sort of a retainer bracket/flange on the outside of the mount..likely it's part of the spring set-up/mounting below.
Any thoughts or insight would be greatly appreciated. Thanks.
Marc
Had another thought/question after I posted the image...looking at the front spring area (#2)...and comparing it to the rear...
the front which is less loaded seems thinner and more vertical, and the rear which is more loaded, sees wider and slightly distorted outward....could these merely be really soft/flexible rubber grommets/dampers?
M
Hard rubber was my first thought before seeing your second post.
So "3" is the bearing seat for the rubber biscuit thingy, "2" is the rubber itself, and "1" is a bracket that bolts to a metal embed cast in the rubber.
Does this make any sense at all?
It almost looks like there is a nut or something on the bottom of "3". This could be a way to compress the rubber to adjust the level of compression on the rubber bearing. Modern expandable hole plugs work the same way.
Don't know if industry was using rubber shock mounts that early. Maybe an adjustable vibration snubber like this one?
Mark
Yes Eric, that does make sense. Thanks.
In that vein then, I think what is/looks like, the bolt under #3 might be some kind of a retainer bolt that is on a shaft running through the bracket at #3, then up through the rubber, and attached somehow at #2. The reason for this thinking, is that on the rear, where the rubber is compressed, this bolt/retainer is protruding further below the bracket than at the uncompressed front.
What I am a bit unclear about, is what that little protrusion is under the bracket at #1. Would that be part of the embeded cast piece?...and if so why would it protrude...and how is it anchored to the Bracket #1
Marc
Just thinking...might there be a rubber or fabric sleeve around a spring to keep the dirt out?
Quote from: marklayton on November 22, 2011, 05:48:39 PM
Don't know if industry was using rubber shock mounts that early. Maybe an adjustable vibration snubber like this one?
Mark
Interesting...that's they type of thing I was thinking about when I first saw this. The part that leads me away from this now though, is that odd deflection compression of #2 at the rear, and the protrusion of that bolt/retainer thing under the lower bracket at the rear.
Tough call (which will be easier to model ;D ?).....this is WW1 Military (Air Corps)...and probably a one-off type of build, (as I have only ever seen various croppings of the same image during my web searches at the time.)...so it might be a somewhat "simple" solution/design.
They do look like elastomeric vibration dampers rather than springs. It looks like there is a heavier load on the rear one. Likely there is a retaining bolt running through it to hold it all together.
Sorry for contradiction, but IMHO it's a simple mechanical thing, working like a bar clip/swing top on bottles or to fasten top covers on battery storage locomotives ... don't have a matching example yet, but I'm thinking of things working like this ...
http://www.pitopia.de/pictures/standard/l/liane/69/liane_117369.jpg (http://www.pitopia.de/pictures/standard/l/liane/69/liane_117369.jpg)
http://www.wm-kanister.de/shop/images/IMGP0054a.JPG (http://www.wm-kanister.de/shop/images/IMGP0054a.JPG)
http://www.wllr.net/image/obj387geo259pg15p8.png (http://www.wllr.net/image/obj387geo259pg15p8.png) (poor quality/resolution)
... but I think you might have recognized what I'm trying to explain ...
EDIT: @Marc - can you eventually show more of that "object" ... ?
Probably off base here but it strikes me as being a type of
vibration isolator used to stop or dampen movement and
vibration transfere.
A couple of examples used in the HVAC industry.
http://www.vibrasystems.com/?EC=Products&CategoryID=0&page=0
http://www.kineticsnoise.com/hvac/
Rick
Hmmm. All good thoughts.
Have you tried a Google patent search? You can define the time period for the search results.
I spent two seconds and found some pretty early rubber isolation widgets for various uses.
Do you think the purpose of these things was just to improve rider comfort? Or was there some other reason for vibration isolation or movement control?
There is a certain similarity to leaf spring shackles.
I unfortunatrly don't want to show the pic at this time.....as I would like to build this when I get done with my current project commitments.
The reason for the. Springs /dampers/grommets was most likely not to smooth or soften the ride, or to isolate any vibration.....but rather to create an unstable platform, be very active and move/flex, to make the task required of the rider, much more difficult.
M
Quote from: marc_reusser on November 23, 2011, 09:26:13 PM
... The reason for the. Springs /dampers/grommets was most likely not to smooth or soften the ride, or to isolate any vibration.....but rather to create an unstable platform, be very active and move/flex, to make the task required of the rider, much more difficult ...
... ??? ??? ??? ... seems/sounds like this "thing" was a fairground attraction ... :D
In a way, this could kind of be like a combination of fairground attractions....definitely would be fun to try.
Thanks to all you guys for all the help and input on this; much appreciated. Really helps to geit input and bounce ideas around.
Through the help of Alex Glass, and Bud Pearson, I was also able to locate a kit, that when I have time for this, will be suitable for cannibalizing the the parts for the top 1/2" of the build....its only $90 :-X ::). [wife said I can buy it for my birthday :-*]...but its a perfect match and will probably save me a couple hundred hours researching and scratchbuilding.
In 3/8 scale, entire model would end up being about 1" x 1-1/2"
Quote from: marc_reusser on November 23, 2011, 09:26:13 PM
I unfortunatrly don't want to show the pic at this time.....as I would like to build this when I get done with my current project commitments.
M
Spoilsport ;D ;D
Quote from: gfadvance on November 24, 2011, 01:06:20 AM
Quote from: marc_reusser on November 23, 2011, 09:26:13 PM
I unfortunatrly don't want to show the pic at this time.....as I would like to build this when I get done with my current project commitments.
M
Spoilsport ;D ;D
......speak of the devil. ;D ;D ;D :P
Actually it is a sort of an arcade game. ;D
Just thinking perhaps 2 is the end of a leaf spring (oriented left to right, not front to rear) and 3 is the flange of the box, which dips down to accomodate the spring, and 1 is the attachment point for the spring.
Dave
Dave,
That was one of the options/solutions I considered at the beginning, for the exact reason you mention, however after a lot of back and forth in PS, It became clear that the bottom hanger had a back, and the lower box continued behind that...so no thru slot/channel into which the leaf spring would sit.
M
Yes, probably right, as it would serve no purpose to extend the flange of the box outward, to accomodate a slot for a leaf spring.
I looked at my reference which shows this photo and a few things come to mind.
You might want to check with the ________ ___ museum for additional photos, as the photo is credited to them and it may have been part of a series. And also in my book it seems to show item 1 as a round horizontal surface, with at least two rivets or nuts , and item 2 might possibly be a simple coiled spring, possibly in a rubber or canvas sock. Just a very simple shock absorber. There's not a lot of load on this thing, so the shocks would not need to be substantial.
Its interesting that the shadows show an angular point, not sure why that would be. I think 3D software can be useful for reverse engineering shapes from a shadow. You can test some ideas and see if they match the odd shadow.
I would assume the drive unit was made of repurposed existing parts. Not sure what industry would use a small remotely operated tramway, but it may lead to more photos of the drive unit.
Dave
Marc
It was not unusual in that era to use rubber for springing rather than metal springs. Check the landing gear of many of the airplanes of the time. You will see big rubber bands wrapped around the axle. Why? Rubber springs do not pick up the sympathetic vibrations and resonance that metal springs do, so do not need shock absorbers. Clever no?
John