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OT. Flail mower interlock wiring
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Richard Savage
Jun 14, 2012, 5:56:15 PM6/14/12
to
I'm only asking because someone here will know the answer and I don't
want to get drawn into a mower 'envy' conversation on the A.F.Mower-
lust newsgroup :-)
My friend who asks awkward questions about bearings has another tricky
one. His ancient flail mower is without any functioning interlocks
which prevent starting it in gear with the clutch engaged. As it has
an 11Hp engine it's quite a handful. There are switches which detect
the position of the clutch handle and whether neutral has been
selected on the gearbox but they are not connected and there is no
loom as such with obvious gaps that they could fill. There is only a
(working) kill-switch which earths part of the ignition circuit.
However, this is supposed to incorporate the gearbox and clutch
switches.
He has asked me to come up with a circuit that does just that. Any
thoughts? I've asked for details of the operation of the two unused
switches. I think that these beasts usually require the clutch to be
held in when starting and this is achieved with a clip rather like
those on the old auto-stop fuel filling nozzles that drops out when
you squeeze the clutch handle.
TIA and happy thinking
Richard
want to get drawn into a mower 'envy' conversation on the A.F.Mower-
lust newsgroup :-)
My friend who asks awkward questions about bearings has another tricky
one. His ancient flail mower is without any functioning interlocks
which prevent starting it in gear with the clutch engaged. As it has
an 11Hp engine it's quite a handful. There are switches which detect
the position of the clutch handle and whether neutral has been
selected on the gearbox but they are not connected and there is no
loom as such with obvious gaps that they could fill. There is only a
(working) kill-switch which earths part of the ignition circuit.
However, this is supposed to incorporate the gearbox and clutch
switches.
He has asked me to come up with a circuit that does just that. Any
thoughts? I've asked for details of the operation of the two unused
switches. I think that these beasts usually require the clutch to be
held in when starting and this is achieved with a clip rather like
those on the old auto-stop fuel filling nozzles that drops out when
you squeeze the clutch handle.
TIA and happy thinking
Richard
Dave Liquorice
Jun 14, 2012, 6:28:57 PM6/14/12
to
On Thu, 14 Jun 2012 14:56:15 -0700 (PDT), Richard Savage wrote:
> He has asked me to come up with a circuit that does just that. Any
> thoughts? I've asked for details of the operation of the two unused
> switches.
Post back when you have that information. Can't do a circuit if we
> He has asked me to come up with a circuit that does just that. Any
> thoughts? I've asked for details of the operation of the two unused
> switches.
don't know how the state of the key components. I have a sneaky
feeling it's not as simple a problem as it first appears.
--
Cheers
Dave.
Richard Savage
Jun 15, 2012, 3:37:47 AM6/15/12
to
On Jun 14, 11:28 pm, "Dave Liquorice"
Hello Dave
First reply from Robin re. switches. (I have asked him to confirm the
operation):
"They are push to make switches. NC when clutch engaged or gear
engaged, NO when not engaged or no gear selected. At least I'm pretty
sure that's the case. I did wire them up originally much as you'd
first think of wiring them up, only to have the engine die when you
engaged *both* clutch and gears."
Indeed, a TT is required. I was trying to work it out 'in my head' as
a means of encouraging sleep last night and agree that it is not
obvious - certainly not to me.
Will come back with the switch detail.
Richard
First reply from Robin re. switches. (I have asked him to confirm the
operation):
"They are push to make switches. NC when clutch engaged or gear
engaged, NO when not engaged or no gear selected. At least I'm pretty
sure that's the case. I did wire them up originally much as you'd
first think of wiring them up, only to have the engine die when you
engaged *both* clutch and gears."
Indeed, a TT is required. I was trying to work it out 'in my head' as
a means of encouraging sleep last night and agree that it is not
obvious - certainly not to me.
Will come back with the switch detail.
Richard
Richard Savage
Jun 15, 2012, 4:02:12 AM6/15/12
to
It's a 1970s or more likely early 80s Saxon pedestrian flail mower
with a Robin EY40B pull start engine fitted with the separate coil and
KTR unit. Both the switches are push to make, the clutch switch makes
on clutch engagement, the gearbox switch makes on reverse gear
selection only. As far as I can work out, they were originally wired
in series as that's what the cable remnants seem to determine.
Richard
Dave Liquorice
Jun 15, 2012, 4:09:50 AM6/15/12
to
On Fri, 15 Jun 2012 00:37:47 -0700 (PDT), Richard Savage wrote:
> "They are push to make switches. NC when clutch engaged or gear
> engaged, NO when not engaged or no gear selected. At least I'm pretty
> sure that's the case. I did wire them up originally much as you'd
> first think of wiring them up, only to have the engine die when you
> engaged *both* clutch and gears."
>
> Indeed, a TT is required. I was trying to work it out 'in my head' as
> a means of encouraging sleep last night and agree that it is not
> obvious - certainly not to me.
I didn't bother thinking about it later but what makes it tricky is
> "They are push to make switches. NC when clutch engaged or gear
> engaged, NO when not engaged or no gear selected. At least I'm pretty
> sure that's the case. I did wire them up originally much as you'd
> first think of wiring them up, only to have the engine die when you
> engaged *both* clutch and gears."
>
> Indeed, a TT is required. I was trying to work it out 'in my head' as
> a means of encouraging sleep last night and agree that it is not
> obvious - certainly not to me.
that:
Clutch in or out, gear in or out are all valid "engine run" states so
if any of those 4 states kills the engine it doesn't work. I can't
help thinking that there must be another (centrifugal?) switch that
indicates that the engine is running and but that would need a
"start" override...
--
Cheers
Dave.
Richard Savage
Jun 15, 2012, 5:00:53 AM6/15/12
to
On Jun 15, 9:09 am, "Dave Liquorice"
Richard
<allsortsnotthis...@howhill.co.uk> wrote:
>
> I didn't bother thinking about it later but what makes it tricky is
> that:
>
> Clutch in or out, gear in or out are all valid "engine run" states so
> if any of those 4 states kills the engine it doesn't work. I can't
> help thinking that there must be another (centrifugal?) switch that
> indicates that the engine is running and but that would need a
> "start" override...
>
> --
> Cheers
> Dave.
Indeed. An interesting conundrum.
>
> I didn't bother thinking about it later but what makes it tricky is
> that:
>
> Clutch in or out, gear in or out are all valid "engine run" states so
> if any of those 4 states kills the engine it doesn't work. I can't
> help thinking that there must be another (centrifugal?) switch that
> indicates that the engine is running and but that would need a
> "start" override...
>
> --
> Cheers
> Dave.
Richard
EMB
Jun 15, 2012, 5:31:19 AM6/15/12
to
interlock may only be designed to kill the engine *if both* the clutch
is engaged (and said clutch is flail drive clutch, not wheel drive
clutch) *and* reverse gear is engaged at the same time in which case a
simple series connection of the switched in parallel with the engine
kill switch should suffice.
Richard Savage
Jun 17, 2012, 7:45:35 AM6/17/12
to
On Jun 15, 10:31 am, EMB <emb...@gmail.com> wrote:
>
> From my reading of the thread and a little thought I suspect the
> interlock may only be designed to kill the engine *if both* the clutch
> is engaged (and said clutch is flail drive clutch, not wheel drive
> clutch) *and* reverse gear is engaged at the same time in which case a
> simple series connection of the switched in parallel with the engine
> kill switch should suffice.
Reply from Robin:
>
> From my reading of the thread and a little thought I suspect the
> interlock may only be designed to kill the engine *if both* the clutch
> is engaged (and said clutch is flail drive clutch, not wheel drive
> clutch) *and* reverse gear is engaged at the same time in which case a
> simple series connection of the switched in parallel with the engine
> kill switch should suffice.
That would be a logical assumption and quite possibly the answer, but
the layout of the belts and clutch levers doesn't lend itself to this
being the logical layout:
There are two hand levers for the two clutches<*1> (calling it a
clutch is glorifying it, it's just a belt tensioner arrangement), one
for the gearbox drive, and one for the flail drive. The clutch lever
on the left handlebar is set up to operate the left belt / clutch
arrangement which operates the gearbox drive, and the clutch lever on
the right handlebar is set up to operate the right belt / clutch
arrangement which operates the flail drive. A simple swapping of the
lever control cables will give the 'no reverse with flails engaged'
scenario detailed below - and as I said above, quite possible the
answer - but the controls / cables / belts layout doesn't lend itself
to this and would explain why the previous owner(s) had installed it
this way.
<*1> Of the two clutch levers, only one has the cut out switch
facility.
Many thanks for the AFL bod who came up with this probable solution.
When back at work on Monday I will see if the cables will fit the
other way around.
cheers,
Robin
SpamTrapSeeSig
Jun 19, 2012, 4:48:51 AM6/19/12
to
In article
<9ce4f59a-438f-473a...@8g2000vbu.googlegroups.com>,
Richard Savage <r...@nildram.co.uk> writes
Is it electric start, or rope?
--
SimonM
<9ce4f59a-438f-473a...@8g2000vbu.googlegroups.com>,
Richard Savage <r...@nildram.co.uk> writes
--
SimonM
SpamTrapSeeSig
Jun 19, 2012, 5:02:01 AM6/19/12
to
In article
<96ac47f9-1880-46b5...@s9g2000vbg.googlegroups.com>,
Richard Savage <r...@nildram.co.uk> writes
I'm late to the party, obviously, but they seem like they were intended
to be cutout switches (preventing a dangerous operation) rather than
start-enable switches, so they won't prevent starting with one or other
engaged, but will kill the motor if you attempt to remove your toes with
the machine.
I'd guess they were wired out by a mower shop at some point in the past,
possibly because they were unreliable (that arrangement isn't failsafe,
and it might be better to not rely on it).
In particular, since the clutch is slipping-belt, is it possible the
lever alignment isn't guaranteed? Could it run without activating the
microswitch?
Also, are the microswitches good enough to work reliably, or might they
clog or jam?
I wonder if starting from scratch might be best.
S.
PS: Ignore my earlier message - I was traversing the other fork of this
thread and you've answered my question about starting.
--
SimonM
<96ac47f9-1880-46b5...@s9g2000vbg.googlegroups.com>,
Richard Savage <r...@nildram.co.uk> writes
to be cutout switches (preventing a dangerous operation) rather than
start-enable switches, so they won't prevent starting with one or other
engaged, but will kill the motor if you attempt to remove your toes with
the machine.
I'd guess they were wired out by a mower shop at some point in the past,
possibly because they were unreliable (that arrangement isn't failsafe,
and it might be better to not rely on it).
In particular, since the clutch is slipping-belt, is it possible the
lever alignment isn't guaranteed? Could it run without activating the
microswitch?
Also, are the microswitches good enough to work reliably, or might they
clog or jam?
I wonder if starting from scratch might be best.
S.
PS: Ignore my earlier message - I was traversing the other fork of this
thread and you've answered my question about starting.
--
SimonM
Richard Savage
Jun 21, 2012, 11:31:22 AM6/21/12
to
On Jun 19, 10:02 am, SpamTrapSeeSig <no-...@nospam.virginmedia.net>
wrote:
> In article
> <96ac47f9-1880-46b5-865f-2f2e57d7f...@s9g2000vbg.googlegroups.com>,
Hi Simon
Robin appears to still be alive, judging from his email traffic, but
hasn't confirmed whether his cable re-routing has worked. I do know,
however, that he is in the process of ordering some Bowden cables.
Richard
wrote:
> In article
> <96ac47f9-1880-46b5-865f-2f2e57d7f...@s9g2000vbg.googlegroups.com>,
Robin appears to still be alive, judging from his email traffic, but
hasn't confirmed whether his cable re-routing has worked. I do know,
however, that he is in the process of ordering some Bowden cables.
Richard
SpamTrapSeeSig
Jun 21, 2012, 12:47:46 PM6/21/12
to
In article
<2c53279d-66e4-48a4...@v9g2000vbc.googlegroups.com>,
Richard Savage <r...@nildram.co.uk> writes
>Robin appears to still be alive, judging from his email traffic, but
>hasn't confirmed whether his cable re-routing has worked. I do know,
>however, that he is in the process of ordering some Bowden cables.
That's a relief.
I had visions of a large blood puddle in the middle of a half-trimmed
rough pasture, and a severed arm, still gripping a phone, with a dying
battery but still bleeping, and flashing "you have mail..."
I may just have been watching too many of those "Inspector Waxwork"
mysteries the wife likes, though.
S.
--
SimonM
<2c53279d-66e4-48a4...@v9g2000vbc.googlegroups.com>,
Richard Savage <r...@nildram.co.uk> writes
>Robin appears to still be alive, judging from his email traffic, but
>hasn't confirmed whether his cable re-routing has worked. I do know,
>however, that he is in the process of ordering some Bowden cables.
I had visions of a large blood puddle in the middle of a half-trimmed
rough pasture, and a severed arm, still gripping a phone, with a dying
battery but still bleeping, and flashing "you have mail..."
I may just have been watching too many of those "Inspector Waxwork"
mysteries the wife likes, though.
S.
--
SimonM
Richard Savage
Jun 25, 2012, 1:15:40 PM6/25/12
to
On Jun 21, 5:47 pm, SpamTrapSeeSig <no-...@nospam.virginmedia.net>
wrote:
> In article
> <2c53279d-66e4-48a4-aeeb-57431a2e8...@v9g2000vbc.googlegroups.com>,
ROFL or perhaps FAOFL (Flail Around On Floor Laughing)
Richard :-)
wrote:
> In article
> <2c53279d-66e4-48a4-aeeb-57431a2e8...@v9g2000vbc.googlegroups.com>,
Richard :-)
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