Metal tape with round or square holes in, engaging with balls or pegs
set in pulleys. Firstly any generic name for this?
I'm after design criteria, for steel tape, 1.25 or 1.5 inches wide,
flexible enough to wrap around 1 foot diameter pulleys.
So the trade-off between tape thickness , size and spacing of
holes/sprockets for maximum tension/torque transfer and tape integrity.

On Sat, 23 Dec 2017 09:31:23 +0000, N_Cook wrote:

Metal tape with round or square holes in, engaging with balls or pegs
set in pulleys. Firstly any generic name for this?
I'm after design criteria, for steel tape, 1.25 or 1.5 inches wide,
flexible enough to wrap around 1 foot diameter pulleys.
So the trade-off between tape thickness , size and spacing of
holes/sprockets for maximum tension/torque transfer and tape integrity.

That sounds like a prescription for fatigue failure, if I understand
you correctly. A lot depends on how big the pulleys are and how long
they're expected to last. Bandsaw blades are made to take it, but the
wheel size has to be large enough to keep the flexing within bounds.

Have you worked that into your design?

--
Ed Huntress

On 23/12/2017 13:32, Ed Huntress wrote:
On Sat, 23 Dec 2017 09:31:23 +0000, N_Cook wrote:

Metal tape with round or square holes in, engaging with balls or pegs
set in pulleys. Firstly any generic name for this?
I'm after design criteria, for steel tape, 1.25 or 1.5 inches wide,
flexible enough to wrap around 1 foot diameter pulleys.
So the trade-off between tape thickness , size and spacing of
holes/sprockets for maximum tension/torque transfer and tape integrity.

That sounds like a prescription for fatigue failure, if I understand
you correctly. A lot depends on how big the pulleys are and how long
they're expected to last. Bandsaw blades are made to take it, but the
wheel size has to be large enough to keep the flexing within bounds.

Have you worked that into your design?


Its actually very very slow action.
Trying to get some insight into a failure mode of this type and model of
tide gauge, this pic and the original in a 1920s publication is other
wise the only info.
http://trigtools.co.uk/data/2GL_AutoTG.JPG
The relevant pair of pulleys are the wide ones , one under the mainframe
and one with the brass cogs.
But resolution in that pic , or the original book , not up to seeing the
sprocket spacing.
The plotter drum records 24x1inch paper for 1 days record, so
circumference of 24 inches, for overall sizing.
The band may well have been bronze as a marine context.
There is surviving plot of when this machine "broke" in service as well
as another one. Both subjected to an extreme tide surge.
The traverse pen mechanism hit the designed-in endstop .
The perforated tape jumped some sprockets and resettled , neatly still
drawing , but displaced downwards. What was the surge level that in a
sense , it recorded. One insight would be the spacing of the teeth, if
only we knew, as it could only be an integre number of the spacing , for
the jump slippage. It was of the order 2 inches to 2.5 inches from
meteorological data etc.

I forgot to say , note the fusee compensator cone on the axis of the
lower pulley. This takes/supplies the perforated tape, winding around
that pulley. The fusee offesetting the varying weight of the suspension
band. Also the large float about 2ft 6 in diameter is shown on the
floor. The suspension must cope with the possibility of that float
puncturing, filling with water, and jamming unsupported by seawater.
Other models of the same make used a simple wire suspension and
returning the counterweight down the sampling well, which then
transfered silt and slime onot the recorder, not the case with the type
pictured.
2 inches on the traverse represents 2 foot of water level change, 1 in
to 1 foot scaling in the gear train.

On Sat, 23 Dec 2017 09:31:23 +0000, N_Cook wrote:

Metal tape with round or square holes in, engaging with balls or pegs
set in pulleys. Firstly any generic name for this?
I'm after design criteria, for steel tape, 1.25 or 1.5 inches wide,
flexible enough to wrap around 1 foot diameter pulleys.
So the trade-off between tape thickness , size and spacing of
holes/sprockets for maximum tension/torque transfer and tape integrity.

https://www.belttechnologies.com/drive-tape-belts/

--
Ned Simmons

"N_Cook" wrote in message
news
I forgot to say , note the fusee compensator cone on the axis of the
lower pulley. This takes/supplies the perforated tape, winding around
that pulley. The fusee offesetting the varying weight of the
suspension band. Also the large float about 2ft 6 in diameter is
shown on the floor. The suspension must cope with the possibility of
that float puncturing, filling with water, and jamming unsupported by
seawater.
Other models of the same make used a simple wire suspension and
returning the counterweight down the sampling well, which then
transfered silt and slime onot the recorder, not the case with the
type pictured.
2 inches on the traverse represents 2 foot of water level change, 1
in to 1 foot scaling in the gear train.


The instrument appears custom made on general-purpose machine tools,
in which case the hole spacing could be whatever the maker's rotary
indexing machinery permitted, and the tape then punched or drilled to
match. The number of pins has to be an integer but the arc length
between them doesn't.

Can you reconstruct the circumference of the wheels?
-jsw

On Sat, 23 Dec 2017 15:24:33 +0000, N_Cook wrote:

On 23/12/2017 13:32, Ed Huntress wrote:
On Sat, 23 Dec 2017 09:31:23 +0000, N_Cook wrote:

Metal tape with round or square holes in, engaging with balls or pegs
set in pulleys. Firstly any generic name for this?
I'm after design criteria, for steel tape, 1.25 or 1.5 inches wide,
flexible enough to wrap around 1 foot diameter pulleys.
So the trade-off between tape thickness , size and spacing of
holes/sprockets for maximum tension/torque transfer and tape integrity.

That sounds like a prescription for fatigue failure, if I understand
you correctly. A lot depends on how big the pulleys are and how long
they're expected to last. Bandsaw blades are made to take it, but the
wheel size has to be large enough to keep the flexing within bounds.

Have you worked that into your design?


Its actually very very slow action.
Trying to get some insight into a failure mode of this type and model of
tide gauge, this pic and the original in a 1920s publication is other
wise the only info.
http://trigtools.co.uk/data/2GL_AutoTG.JPG
The relevant pair of pulleys are the wide ones , one under the mainframe
and one with the brass cogs.
But resolution in that pic , or the original book , not up to seeing the
sprocket spacing.
The plotter drum records 24x1inch paper for 1 days record, so
circumference of 24 inches, for overall sizing.
The band may well have been bronze as a marine context.
There is surviving plot of when this machine "broke" in service as well
as another one. Both subjected to an extreme tide surge.
The traverse pen mechanism hit the designed-in endstop .
The perforated tape jumped some sprockets and resettled , neatly still
drawing , but displaced downwards. What was the surge level that in a
sense , it recorded. One insight would be the spacing of the teeth, if
only we knew, as it could only be an integre number of the spacing , for
the jump slippage. It was of the order 2 inches to 2.5 inches from
meteorological data etc.

Aha. Now I see what it's about. That's an interesting old recording
machine.

--
Ed Huntress

On 23/12/2017 18:17, Ed Huntress wrote:
On Sat, 23 Dec 2017 15:24:33 +0000, N_Cook wrote:

On 23/12/2017 13:32, Ed Huntress wrote:
On Sat, 23 Dec 2017 09:31:23 +0000, N_Cook wrote:

Metal tape with round or square holes in, engaging with balls or pegs
set in pulleys. Firstly any generic name for this?
I'm after design criteria, for steel tape, 1.25 or 1.5 inches wide,
flexible enough to wrap around 1 foot diameter pulleys.
So the trade-off between tape thickness , size and spacing of
holes/sprockets for maximum tension/torque transfer and tape integrity.

That sounds like a prescription for fatigue failure, if I understand
you correctly. A lot depends on how big the pulleys are and how long
they're expected to last. Bandsaw blades are made to take it, but the
wheel size has to be large enough to keep the flexing within bounds.

Have you worked that into your design?


Its actually very very slow action.
Trying to get some insight into a failure mode of this type and model of
tide gauge, this pic and the original in a 1920s publication is other
wise the only info.
http://trigtools.co.uk/data/2GL_AutoTG.JPG
The relevant pair of pulleys are the wide ones , one under the mainframe
and one with the brass cogs.
But resolution in that pic , or the original book , not up to seeing the
sprocket spacing.
The plotter drum records 24x1inch paper for 1 days record, so
circumference of 24 inches, for overall sizing.
The band may well have been bronze as a marine context.
There is surviving plot of when this machine "broke" in service as well
as another one. Both subjected to an extreme tide surge.
The traverse pen mechanism hit the designed-in endstop .
The perforated tape jumped some sprockets and resettled , neatly still
drawing , but displaced downwards. What was the surge level that in a
sense , it recorded. One insight would be the spacing of the teeth, if
only we knew, as it could only be an integre number of the spacing , for
the jump slippage. It was of the order 2 inches to 2.5 inches from
meteorological data etc.

Aha. Now I see what it's about. That's an interesting old recording
machine.


The thing on the right is probably an "Aga" stove.
Not for cooking purposes but for some warmth.
There was notorious problems of condensation freezing in the and jamming
the mechanism. Not just that, but the lubrication gummed up , and close
to frictionless operation is required for accurate recording.

On 23/12/2017 17:51, Jim Wilkins wrote:
"N_Cook" wrote in message
news
I forgot to say , note the fusee compensator cone on the axis of the
lower pulley. This takes/supplies the perforated tape, winding around
that pulley. The fusee offesetting the varying weight of the
suspension band. Also the large float about 2ft 6 in diameter is
shown on the floor. The suspension must cope with the possibility of
that float puncturing, filling with water, and jamming unsupported by
seawater.
Other models of the same make used a simple wire suspension and
returning the counterweight down the sampling well, which then
transfered silt and slime onot the recorder, not the case with the
type pictured.
2 inches on the traverse represents 2 foot of water level change, 1
in to 1 foot scaling in the gear train.


The instrument appears custom made on general-purpose machine tools,
in which case the hole spacing could be whatever the maker's rotary
indexing machinery permitted, and the tape then punched or drilled to
match. The number of pins has to be an integer but the arc length
between them doesn't.

Can you reconstruct the circumference of the wheels?
-jsw



Other than this pic, the only dimensional data is the recording drum is
24/Pi inches in diameter, the axial lengths varied .
I only roughly scaled the dimensions to arrive at 12 inch diameter
puppey wheels. I'll have another go as because of non factorable Pi, it
cannot be exactly 12 inches diameter.
Only the upper pulley is spoked, the lower has the end of the tape
anchored to it , and rolls up the excess, can be 20 foot of tape plus
the standing length for the overall length.

On 2017-12-23, N_Cook wrote:
Metal tape with round or square holes in, engaging with balls or pegs
set in pulleys. Firstly any generic name for this?
I'm after design criteria, for steel tape, 1.25 or 1.5 inches wide,

Hmmm ... sprockets for 35mm film -- two rows of square holes
near both edges of the film.

flexible enough to wrap around 1 foot diameter pulleys.

Well ... 35mm film is flexible enough to wrap around about 1/2"
diameter sprockets -- but obviously likely not strong enough for your
purposes. But the sprockets themselves may be more readily available
than other sizes. Then comes the trick of finding the steel tape to do
what you want.

So the trade-off between tape thickness , size and spacing of
holes/sprockets for maximum tension/torque transfer and tape integrity.

At 1 foot diameter sprocket, at a total guess, (no calculation,
not sure where to start) I think that you could get away with perhaps
0.050" thick steel tape. You can look up the dimensions of 35mm film
and sprocket holes, figure out how much area a cross-section of the film
or steep tape would leave, and calculate the tensile strength. With
that much hub (assuming a 180 degree wrap), you probably would have
enough sprocket teeth engaging so the tensile strength of the
unsupported tape would be the limiting factor.

Or -- look at suppliers like PIC, who make steel cable with
cross pins, and paired gear teeth to go on either side of the cable and
engage the pins. If that format, instead of flat tape, would work for
your purposes, they can provide lots of calculation data for your
application.

Good Luck,
DoN.

--
Remove oil spill source from e-mail
Email: | (KV4PH) Voice (all times): (703) 938-4564
(too) near Washington D.C. | http://www.d-and-d.com/dnichols/DoN.html
--- Black Holes are where God is dividing by zero ---

On 23-Dec-17 5:31 PM, N_Cook wrote:
Metal tape with round or square holes in, engaging with balls or pegs
set in pulleys. Firstly any generic name for this?
I'm after design criteria, for steel tape, 1.25 or 1.5 inches wide,
flexible enough to wrap around 1 foot diameter pulleys.
So the trade-off between tape thickness , size and spacing of
holes/sprockets for maximum tension/torque transfer and tape integrity.

Most of these systems now use beaded float line.

Multi-strand stainless wire has brass beads peened on every 6" or so.
The pulleys have holes that line up with the beads.

"N_Cook" wrote in message
news
On 23/12/2017 13:32, Ed Huntress wrote:
On Sat, 23 Dec 2017 09:31:23 +0000, N_Cook
wrote:

Metal tape with round or square holes in, engaging with balls or
pegs
set in pulleys. Firstly any generic name for this?
I'm after design criteria, for steel tape, 1.25 or 1.5 inches
wide,
flexible enough to wrap around 1 foot diameter pulleys.
So the trade-off between tape thickness , size and spacing of
holes/sprockets for maximum tension/torque transfer and tape
integrity.

That sounds like a prescription for fatigue failure, if I
understand
you correctly. A lot depends on how big the pulleys are and how
long
they're expected to last. Bandsaw blades are made to take it, but
the
wheel size has to be large enough to keep the flexing within
bounds.

Have you worked that into your design?


Its actually very very slow action.
Trying to get some insight into a failure mode of this type and
model of tide gauge, this pic and the original in a 1920s
publication is other wise the only info.
http://trigtools.co.uk/data/2GL_AutoTG.JPG
The relevant pair of pulleys are the wide ones , one under the
mainframe and one with the brass cogs.
But resolution in that pic , or the original book , not up to seeing
the sprocket spacing.
The plotter drum records 24x1inch paper for 1 days record, so
circumference of 24 inches, for overall sizing.
The band may well have been bronze as a marine context.
There is surviving plot of when this machine "broke" in service as
well as another one. Both subjected to an extreme tide surge.
The traverse pen mechanism hit the designed-in endstop .
The perforated tape jumped some sprockets and resettled , neatly
still drawing , but displaced downwards. What was the surge level
that in a sense , it recorded. One insight would be the spacing of
the teeth, if only we knew, as it could only be an integre number of
the spacing , for the jump slippage. It was of the order 2 inches to
2.5 inches from meteorological data etc.


I suspect the strength of the engagement between the tape and sprocket
wasn't a primary consideration, as the sprocket drove only the
plotting mechanism. Does an easy-to-index factor of 360 such as 12, 24
or 36 make sense as the number of sprocket pins?

A sprocket of 11.459" diameter would revolve once per 3' of band
travel. It might have 24 pins spaced 1.500" apart, or 36 at 1.000". A
7.639" diameter sprocket would correspond to 2'.

The fusee and the frame suggest that a tower (turret) clock maker
built it, so a 30 tooth sprocket is possible.
http://www.model-engineer.co.uk/foru...s.asp?th=75826

This shows a clock built on a similar frame:
https://en.wikipedia.org/wiki/Turret...k_movement.png
-jsw

Jim Wilkins wrote:
"N_Cook" wrote in message
news
On 23/12/2017 13:32, Ed Huntress wrote:
On Sat, 23 Dec 2017 09:31:23 +0000, N_Cook
wrote:

Metal tape with round or square holes in, engaging with balls or
pegs
set in pulleys. Firstly any generic name for this?
I'm after design criteria, for steel tape, 1.25 or 1.5 inches
wide,
flexible enough to wrap around 1 foot diameter pulleys.
So the trade-off between tape thickness , size and spacing of
holes/sprockets for maximum tension/torque transfer and tape
integrity.

That sounds like a prescription for fatigue failure, if I
understand
you correctly. A lot depends on how big the pulleys are and how
long
they're expected to last. Bandsaw blades are made to take it, but
the
wheel size has to be large enough to keep the flexing within
bounds.

Have you worked that into your design?


Its actually very very slow action.
Trying to get some insight into a failure mode of this type and
model of tide gauge, this pic and the original in a 1920s
publication is other wise the only info.
http://trigtools.co.uk/data/2GL_AutoTG.JPG
The relevant pair of pulleys are the wide ones , one under the
mainframe and one with the brass cogs.
But resolution in that pic , or the original book , not up to seeing
the sprocket spacing.
The plotter drum records 24x1inch paper for 1 days record, so
circumference of 24 inches, for overall sizing.
The band may well have been bronze as a marine context.
There is surviving plot of when this machine "broke" in service as
well as another one. Both subjected to an extreme tide surge.
The traverse pen mechanism hit the designed-in endstop .
The perforated tape jumped some sprockets and resettled , neatly
still drawing , but displaced downwards. What was the surge level
that in a sense , it recorded. One insight would be the spacing of
the teeth, if only we knew, as it could only be an integre number of
the spacing , for the jump slippage. It was of the order 2 inches to
2.5 inches from meteorological data etc.


I suspect the strength of the engagement between the tape and sprocket
wasn't a primary consideration, as the sprocket drove only the
plotting mechanism. Does an easy-to-index factor of 360 such as 12, 24
or 36 make sense as the number of sprocket pins?

A sprocket of 11.459" diameter would revolve once per 3' of band
travel. It might have 24 pins spaced 1.500" apart, or 36 at 1.000". A
7.639" diameter sprocket would correspond to 2'.


He's in England, so it may be metric with a one meter circumference
which would make the diameter closer to 12.5"


The fusee and the frame suggest that a tower (turret) clock maker
built it, so a 30 tooth sprocket is possible.
http://www.model-engineer.co.uk/foru...s.asp?th=75826

This shows a clock built on a similar frame:
https://en.wikipedia.org/wiki/Turret...k_movement.png
-jsw

On 2017-12-24, Jim Wilkins wrote:

[ ... ]

I suspect the strength of the engagement between the tape and sprocket
wasn't a primary consideration, as the sprocket drove only the
plotting mechanism. Does an easy-to-index factor of 360 such as 12, 24
or 36 make sense as the number of sprocket pins?

Hmm ... O.K. 35mm film has the sprocket holes on 0.1875"
centers. You can get lots of details from the following WikiPedia
page:

https://en.wikipedia.org/wiki/35_mm_film#Perforations

You can calculate the possible sprocket wheel sizes based on
that. The sprocket wheels in 35mm hand held cameras (not movie)
actually skip every other hole, but they only have to pull the film out
of the cassette, which does not take much force.

A thought about the intended purpose of the application suggests
that instead of having the fusee to counter the weight of tape above,
you could use the mylar film base used on modern films (movie and still
camera), and make it a complete loop over two identical sprocket wheels.
This would have an equal weight of film between the wheels, no matter
what the position of the float happens to be, thus no need for
correction.

Of course the film is not strong enough to support the
worst-case situation of a flooded float, but the float could be allowed
to slide up and down on fixed guide rods, with a link to the side
coupling it to the film to transfer the position.

I would enclose the film within a U-shaped housing to keep the
wave forces from tugging at the film.

A sprocket of 11.459" diameter would revolve once per 3' of band
travel. It might have 24 pins spaced 1.500" apart, or 36 at 1.000". A
7.639" diameter sprocket would correspond to 2'.

With the 35mm sprocket, I calculate 192 pins for a 36" (3')
length. Of course, you could skip every other pin as the 35mm still
cameras do. Or using one out of four pins, you get 48 pins. And with
Mylar film, it should be strong enough to last a reasonable while under
water. And I would suggest making the sprocket wheels via 3D printing,
so it would be similarly waterproof and corrosion proof.

The fusee and the frame suggest that a tower (turret) clock maker
built it, so a 30 tooth sprocket is possible.
http://www.model-engineer.co.uk/foru...s.asp?th=75826

No fusee needed if you have a complete loop with wheels at top
and bottom.

This shows a clock built on a similar frame:
https://en.wikipedia.org/wiki/Turret...k_movement.png
-jsw

O.K.

Enjoy,
DoN.

--
Remove oil spill source from e-mail
Email: | (KV4PH) Voice (all times): (703) 938-4564
(too) near Washington D.C. | http://www.d-and-d.com/dnichols/DoN.html
--- Black Holes are where God is dividing by zero ---

I suspect the strength of the engagement between the tape and sprocket
wasn't a primary consideration, as the sprocket drove only the
plotting mechanism. Does an easy-to-index factor of 360 such as 12, 24
or 36 make sense as the number of sprocket pins?

A sprocket of 11.459" diameter would revolve once per 3' of band
travel. It might have 24 pins spaced 1.500" apart, or 36 at 1.000". A
7.639" diameter sprocket would correspond to 2'.

The fusee and the frame suggest that a tower (turret) clock maker
built it, so a 30 tooth sprocket is possible.
http://www.model-engineer.co.uk/foru...s.asp?th=75826

This shows a clock built on a similar frame:
https://en.wikipedia.org/wiki/Turret...k_movement.png
-jsw



Associated pages to that pic of the gauge
http://trigtools.co.uk/data/2GLMain_24.htm
http://trigtools.co.uk/data/2GLMain_25.htm

Looks like an exploration of the background to the Cary & Porter company
as to any clockmaking connection.

Same company tide gauges , but the models using the troublesome
counterbalance going down the stilling well, and no metal tape
(ignore what I was saying on there about slippage in the traverse area,
moved on from that)
https://www.ordnancesurvey.co.uk/blo...-our-antiques/

going by the B&W graphic , the original model, not the one in coloured
pic ,
was one of these earlier fusee, and perforated tape suspension models
http://www.tandfonline.com/doi/pdf/1...9.2015.1121175

Busy today, but i'll try pixel counting on those "trigtools "
" images.
The pulleys ,rather than gear wheels, have a reinforcement flange on the
inside of torque/tension bearing flange, so the tape is quite recessed
into those pulley rims .

"N_Cook" wrote in message
news


I suspect the strength of the engagement between the tape and
sprocket
wasn't a primary consideration, as the sprocket drove only the
plotting mechanism. Does an easy-to-index factor of 360 such as 12,
24
or 36 make sense as the number of sprocket pins?

A sprocket of 11.459" diameter would revolve once per 3' of band
travel. It might have 24 pins spaced 1.500" apart, or 36 at 1.000".
A
7.639" diameter sprocket would correspond to 2'.

The fusee and the frame suggest that a tower (turret) clock maker
built it, so a 30 tooth sprocket is possible.
http://www.model-engineer.co.uk/foru...s.asp?th=75826

This shows a clock built on a similar frame:
https://en.wikipedia.org/wiki/Turret...k_movement.png
-jsw



Associated pages to that pic of the gauge
http://trigtools.co.uk/data/2GLMain_24.htm
http://trigtools.co.uk/data/2GLMain_25.htm

Looks like an exploration of the background to the Cary & Porter
company as to any clockmaking connection.

Same company tide gauges , but the models using the troublesome
counterbalance going down the stilling well, and no metal tape
(ignore what I was saying on there about slippage in the traverse
area, moved on from that)
https://www.ordnancesurvey.co.uk/blo...-our-antiques/

going by the B&W graphic , the original model, not the one in
coloured pic ,
was one of these earlier fusee, and perforated tape suspension
models
http://www.tandfonline.com/doi/pdf/1...9.2015.1121175

Busy today, but i'll try pixel counting on those "trigtools "
" images.
The pulleys ,rather than gear wheels, have a reinforcement flange on
the inside of torque/tension bearing flange, so the tape is quite
recessed into those pulley rims .

Is it possible to determine from records whether the transient that
caused the skip was due to a brief nearby ship launching or a longer
lasting storm surge?
-jsw

More interesting than the other stuff i should have been doing.

From 24 inch circumference of the recording drum I make the key data
for that top image 0.0868 inches per pixel, vertical and horizontal, as
circular wheels. The clocks were 10 day , allowing 7 days of continuous
recording on one sheet of paper, much overlapping of about 19 tide
cycles, before having to change paper and re-synching. Hence accurately
inferred diameter dimension there.
I reckon, from 20 foot of tide range, 7 turns of tape ,then from the
following, 1 1/3 inches wide and 0.083 inches ,probably 5/64 inch, thick
tape.
The spigotted pulley , the measurement-active bearing face , between
11.08 in and 11.13 in diameter.
So for a jump between 2 and 2.5 inches, if perforations spacing 0.75 in
between centres, then 46 spigots and jumped 3, 2.25 inches, pulley
diameter 10.98 in.
If 1 inch spacing, 35 spigots, jumped 2 , or 2 inches, pulley diam 11.14 in
If 1.25 in spacing ,28 spigots, jumped 2 or 2.5 inches, diam 11.14 in
If 4/3 inch spacing , 26 spigots, jump of 1 or 2 is outside the 2 to
2.5 inch range, but if so, then pulley 11.03 in diam .

For the tape width appearing to the left wide side on, from the lower
image , ratioed pixels to the diameter of the suspension band
counterweight and then used the upper image to get 1.33 inches.
The lower image shows the recess in the rim of the upper spigotted
pulley, assumed to have one thickness of tape on it.
From the twisty looking appearance the tape band is broken or cut, and
just draped through near and to the rear of the lower pulley,not wound
on it , same diameter as the upper one ,same recess , but no spigots on
that one.

The failure mechanism , prior to jump, as a band suspension.
12:1 gearing stops, so spigotted pulley stops rotating, the float
continues rising. Band disengages from pulley, counterweight takes up
the slack 1 ,2 or 3 times, until the float goes back down again.

Is it possible to determine from records whether the transient that
caused the skip was due to a brief nearby ship launching or a longer
lasting storm surge?
-jsw



The background is the anomaly surrounding the surge of 26/27 Nov 1924 on
my page (an update should go there today or tomorrow)
http://diverse.4mg.com/solent.htm
The official record did not agree with contemporaneous press reports,
nor the meteorology of the day. I should say I'm involved with a couple
of a couple of academics at the Southampton National Oceanography Centre
.. Trying to get to the bottom of this 1924 event, and then the GIGO
business of "return periods" for marine surge flooding events ,ie
inadvertently downplaying the risk in effect.

"N_Cook" wrote in message
news

...
Looks like an exploration of the background to the Cary & Porter
company as to any clockmaking connection.


A connection may not be apparent. I studied watch and clock precision
machining techniques while I was involved in developing GPS-related
electronics for the US Air Force. At microwave frequencies signals
interact with nearby metal and being able to machine custom enclosures
as needed rather than draw them up and contract them out was extremely
useful.
https://books.google.com/books/about...d=FC9KAQAAMAAJ
-jsw

"N_Cook" wrote in message
news
More interesting than the other stuff i should have been doing.

From 24 inch circumference of the recording drum I make the key data
for that top image 0.0868 inches per pixel, vertical and horizontal,
as circular wheels. The clocks were 10 day , allowing 7 days of
continuous recording on one sheet of paper, much overlapping of
about 19 tide cycles, before having to change paper and re-synching.
Hence accurately inferred diameter dimension there.
I reckon, from 20 foot of tide range, 7 turns of tape ,then from the
following, 1 1/3 inches wide and 0.083 inches ,probably 5/64 inch,
thick tape.
The spigotted pulley , the measurement-active bearing face , between
11.08 in and 11.13 in diameter.
So for a jump between 2 and 2.5 inches, if perforations spacing 0.75
in between centres, then 46 spigots and jumped 3, 2.25 inches,
pulley diameter 10.98 in.
If 1 inch spacing, 35 spigots, jumped 2 , or 2 inches, pulley diam
11.14 in
If 1.25 in spacing ,28 spigots, jumped 2 or 2.5 inches, diam 11.14
in
If 4/3 inch spacing , 26 spigots, jump of 1 or 2 is outside the 2
to 2.5 inch range, but if so, then pulley 11.03 in diam .
...

It's easier to space the holes in the tape at some arbitrary
non-integer distance than to divide the wheel by an odd number, unless
the maker already has the correct index plate. 24 is particularly
easy.

This is a modern example of a classic design. I have an indexer that
may date from the 1880's.
https://www.amazon.com/BS-0-Dividing.../dp/B013ZDX6XQ
-jsw

On 24/12/2017 14:02, Jim Wilkins wrote:
"N_Cook" wrote in message
news
More interesting than the other stuff i should have been doing.

From 24 inch circumference of the recording drum I make the key data
for that top image 0.0868 inches per pixel, vertical and horizontal,
as circular wheels. The clocks were 10 day , allowing 7 days of
continuous recording on one sheet of paper, much overlapping of
about 19 tide cycles, before having to change paper and re-synching.
Hence accurately inferred diameter dimension there.
I reckon, from 20 foot of tide range, 7 turns of tape ,then from the
following, 1 1/3 inches wide and 0.083 inches ,probably 5/64 inch,
thick tape.
The spigotted pulley , the measurement-active bearing face , between
11.08 in and 11.13 in diameter.
So for a jump between 2 and 2.5 inches, if perforations spacing 0.75
in between centres, then 46 spigots and jumped 3, 2.25 inches,
pulley diameter 10.98 in.
If 1 inch spacing, 35 spigots, jumped 2 , or 2 inches, pulley diam
11.14 in
If 1.25 in spacing ,28 spigots, jumped 2 or 2.5 inches, diam 11.14
in
If 4/3 inch spacing , 26 spigots, jump of 1 or 2 is outside the 2
to 2.5 inch range, but if so, then pulley 11.03 in diam .
...

It's easier to space the holes in the tape at some arbitrary
non-integer distance than to divide the wheel by an odd number, unless
the maker already has the correct index plate. 24 is particularly
easy.

This is a modern example of a classic design. I have an indexer that
may date from the 1880's.
https://www.amazon.com/BS-0-Dividing.../dp/B013ZDX6XQ
-jsw



These machines were semi-custom made, the axial length of the plotter
drum , varied for different sites with widely different tide ranges.

So custom made tapes along with custom-made plotter papers
makes sense.

Especially as I'd not allowed for parallax in the lower view. Taking
that into account, the width of tape cpmes out to 1.62 inches, perhaps 1
5/8 in wide. Spiggot spacing of 13/8 inches would not give 2 to 2.5 inch
slip , but 13/16 spacing would. But then 43 spiggots to a pulley of
11.12 in diameter. Setting a dividing circle to 43? com[ared to step and
repeat punching at any desired interval makes sense.
So looks like non-standard holes pitch on the tape for sensible number
of spiggots, ie that idea comes to a grinding halt, to zero in on the
slippage value.

"N_Cook" wrote in message
news
More interesting than the other stuff i should have been doing.

From 24 inch circumference of the recording drum I make the key data
for that top image 0.0868 inches per pixel, vertical and horizontal,
as circular wheels. The clocks were 10 day , allowing 7 days of
continuous recording on one sheet of paper, much overlapping of
about 19 tide cycles, before having to change paper and re-synching.
Hence accurately inferred diameter dimension there.
I reckon, from 20 foot of tide range, 7 turns of tape ,then from the
following, 1 1/3 inches wide and 0.083 inches ,probably 5/64 inch,
thick tape.
The spigotted pulley , the measurement-active bearing face , between
11.08 in and 11.13 in diameter.
So for a jump between 2 and 2.5 inches, if perforations spacing 0.75
in between centres, then 46 spigots and jumped 3, 2.25 inches,
pulley diameter 10.98 in.
If 1 inch spacing, 35 spigots, jumped 2 , or 2 inches, pulley diam
11.14 in
If 1.25 in spacing ,28 spigots, jumped 2 or 2.5 inches, diam 11.14
in
If 4/3 inch spacing , 26 spigots, jump of 1 or 2 is outside the 2
to 2.5 inch range, but if so, then pulley 11.03 in diam .

For the tape width appearing to the left wide side on, from the
lower image , ratioed pixels to the diameter of the suspension band
counterweight and then used the upper image to get 1.33 inches.
The lower image shows the recess in the rim of the upper spigotted
pulley, assumed to have one thickness of tape on it.
From the twisty looking appearance the tape band is broken or cut,
and just draped through near and to the rear of the lower pulley,not
wound on it , same diameter as the upper one ,same recess , but no
spigots on that one.

The failure mechanism , prior to jump, as a band suspension.
12:1 gearing stops, so spigotted pulley stops rotating, the float
continues rising. Band disengages from pulley, counterweight takes
up the slack 1 ,2 or 3 times, until the float goes back down again.

Presumably the band was cut from sheet stock of a commercial
thickness. For such a low production count it would be hard to justify
not buying standard components wherever possible.

(36" / pi) - 0.08" gives 11.38" for a diameter that would move the
neutral plane of the band 36" per revolution. If the camera wasn't at
the level of the wheel its apparent height would be foreshortened but
the round drum's diameter wouldn't.
-jsw

"N_Cook" wrote in message
news
On 24/12/2017 14:02, Jim Wilkins wrote:
"N_Cook" wrote in message
news
More interesting than the other stuff i should have been doing.

From 24 inch circumference of the recording drum I make the key
data
for that top image 0.0868 inches per pixel, vertical and
horizontal,
as circular wheels. The clocks were 10 day , allowing 7 days of
continuous recording on one sheet of paper, much overlapping of
about 19 tide cycles, before having to change paper and
re-synching.
Hence accurately inferred diameter dimension there.
I reckon, from 20 foot of tide range, 7 turns of tape ,then from
the
following, 1 1/3 inches wide and 0.083 inches ,probably 5/64 inch,
thick tape.
The spigotted pulley , the measurement-active bearing face ,
between
11.08 in and 11.13 in diameter.
So for a jump between 2 and 2.5 inches, if perforations spacing
0.75
in between centres, then 46 spigots and jumped 3, 2.25 inches,
pulley diameter 10.98 in.
If 1 inch spacing, 35 spigots, jumped 2 , or 2 inches, pulley diam
11.14 in
If 1.25 in spacing ,28 spigots, jumped 2 or 2.5 inches, diam 11.14
in
If 4/3 inch spacing , 26 spigots, jump of 1 or 2 is outside the 2
to 2.5 inch range, but if so, then pulley 11.03 in diam .
...

It's easier to space the holes in the tape at some arbitrary
non-integer distance than to divide the wheel by an odd number,
unless
the maker already has the correct index plate. 24 is particularly
easy.

This is a modern example of a classic design. I have an indexer
that
may date from the 1880's.
https://www.amazon.com/BS-0-Dividing.../dp/B013ZDX6XQ
-jsw



These machines were semi-custom made, the axial length of the
plotter drum , varied for different sites with widely different tide
ranges.

So custom made tapes along with custom-made plotter papers
makes sense.

Especially as I'd not allowed for parallax in the lower view. Taking
that into account, the width of tape cpmes out to 1.62 inches,
perhaps 1 5/8 in wide. Spiggot spacing of 13/8 inches would not give
2 to 2.5 inch slip , but 13/16 spacing would. But then 43 spiggots
to a pulley of 11.12 in diameter. Setting a dividing circle to 43?
com[ared to step and repeat punching at any desired interval makes
sense.
So looks like non-standard holes pitch on the tape for sensible
number of spiggots, ie that idea comes to a grinding halt, to zero
in on the slippage value.

I doubt that the perforated tape was a standard product.
It could have been sheared to any desired width from a roll of shim
stock,
https://www.kbctools.com/contentonly.../1-953-S10.jpg
and the holes laid out with dividers.
https://smithy.com/machining-handbook/chapter-1/page/3
I could make one myself with hand tools.
https://www.roperwhitney.com/our-pro...jr-hand-punch/

If the effective circumference is indeed 36" as I suspect then
easy-to-generate pin counts give reasonable spacings within your
estimated slip range; 1" or 2" for 36 pins and 2.25" for 16 pins. 2.5"
gives 14.4 pins. 24 pins would jump by 1.5" or 3". I'd check if 16 or
18 fit the evidence.
-jsw