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RE: (ET) Satellite Actuator Arm
When I said "cut off the peak" I was referring to exactly your
point about mountain climbers. However, the strap and winch
mechanism must be capable of handling the force - a stretchy strap will
still require the winch to support 300 pounds (for example) after it has
reached the limit of its elasticity. When your mountain climber is
stationary, a cable and a strap can both support him. If he falls
with a slack line for a while, the strap will be decidedly kinder.
But when the stretch is all gone the line anchor will be required to
resist the same amount of force as would have been the case with a solid
cable attached. Since one of the issues here was the gear drive in
the lift motor, I made the point that at some load level, a strap and
cable will both stress out the lift gears equally. I am guessing
that lifting a heavy tiller will take 99% of the stretch out of the strap
- it is close to becoming a cable at this point.
At 09:07 PM 11/29/2004, Rob Brockway wrote:
If you consider the bump as
imparting a fixed quantity of energy, then the force is inversly
proportional to the distance that the energy is absorbed. So I
think the softer strap would lower the forces. A rock climber wants
his safety rope made of strong stretchable rope - Low force over a long
distance. Not aircraft cable that would stop him in a short high
force distance.
I find it hard to believe however, that the complience of the tires would
not be a larger factor than the strap vs cable.
Pieter <pvcl plitch com> wrote:
- At 03:56 PM 11/29/2004, Markus Lorch wrote:
- It seems to me that the
total force exerted by a lever on a cable is the same if that cable is
stiff or "forgiving." I'll grant you that the nylon strap
may "cut the peak off" of some transient noise in the
application of the load, but the force is the same no matter what you use
as a cable. That being said, I would suggest that you could always
double the winch cable - anchor the hook end at the winch (but not on the
winch) and use a snatch block at the load. The would double the
load the winch's internal gearing and the cable could handle. Of
course, your raise/lower speed is cut in half too. But safety
first. I use a snatch block with an ATV winch quite often -
sometimes to pull in some other direction than straight ahead, more often
to lessen the load on the winch.
- I use electric actuators (12 volt) to raise and lower a dump box on
an ATV trailer and the cutting edge on an X-C ski trail groomer pulled
behind a snowmobile. The dump trailer uses an electric trailer
jack, and takes about a minute extending 24 inches. The groomer
actuator is one I picked up on e-bay. It will extend 12 inches in
about 15 seconds. In both cases, the actuator does not carry a lot
of load during normal operation. For example, the dump cart is only
transported in the fully down position with the load entirely resting on
the trailer frame. The force against the cutting edge of the ski
trail groomer is mostly horizontal while the actuator is vertical, so
virtually no shock impacts the actuator. If you do a Google search
on +36VDC +"linear actuator" you will find a lot of
info.
- I have written here before about building a front bucket loader using
36 volt linear actuators rather than hydraulics. While the
electrics might be slower, I am guessing that they could be cheaper and
less power hungry. There are a few technical problems (like
"synching" the actuators on both sides to each other), but it
is an interesting concept.
- Bob and others,
-
- the new elec-trak.org forum
has the capability to publish your posts incl. pictures. So you
could
- create a thread there on satelite actuators, copy your text that you
send via emails
- and add the pictures. Then sent a note to the list informing us about
the location of the pictures.
-
- If you don't want to go
this route I'd be happy to put your pictures on my webserver and
- make them available to everyone. I think thought he forum is the way
to go.
-
- One note about the
actuators. I am not sure how well they handle the forces of implements
- when driving over bumps with the implements lifted. I got a warning
from Warn winches about
- me using a 1700# winch to lift a bucket - they thought the lever
distance and the high forces
- envolved when absorbing a bump may be too much for my geartrain when
driving with a full
- bucket. The original elec-trak strap would absorb some of these
forces as it is a little bit
- elastic. I am considering putting a nylon strap on my winch instead
of the steel cable
- to get the same effect.
-
- Markus
-
- -----Original Message-----
- From: elec-trak-bounces cosmos phy tufts edu [
mailto:elec-trak-bounces cosmos phy tufts edu] On Behalf Of
Kleinbrahm, Bob
- Sent: Montag, 29. November 2004 15:46
- To: Elie, Larry (L.D.); elec-trak cosmos phy tufts edu
- Subject: RE: (ET) Satellite Actuator Arm
- I am not at the location of
my tractor during the week, so I won't be able to time it until the
weekend. It seemed to have adequate movement within 10 - 30
seconds, and doesn't stop me from using it. I will take pictures
next weekend, but do not have a place to post them on, so am not sure if
I can share them or not.
-
- Bob
- -----Original Message-----
- From: Elie, Larry (L.D.) [
mailto:lelie ford com
]
- Sent: Monday, November 29, 2004 11:39 AM
- To: Kleinbrahm, Bob; elec-trak cosmos phy tufts edu
- Subject: RE: (ET) Satellite Actuator Arm
- Great! Pictures
Please!
-
- My actuator (Von Weiss) was too
slow to implement, nearly a minute for 24"; how fast can you
raise/lower your tiller?
-
- Larry Elie
-
- -----Original Message-----
- From: elec-trak-bounces cosmos phy tufts edu [
mailto:elec-trak-bounces cosmos phy tufts edu]On Behalf Of
Kleinbrahm, Bob
- Sent: Monday, November 29, 2004 1:58 PM
- To: elec-trak cosmos phy tufts edu
- Subject: (ET) Satellite Actuator Arm
-
- To the Group:
-
- All the current talk about lift straps
breaking prompted me to send this message. I too was plaqued with
those darn straps and the limited support that they provide. A few
weeks back I posted messages about using a Satellite Actuator arm to
replace the front lift on my E-20 tractor. I have since modified
the rear lift to use an actuator in place of the strap, etc.. I
used the actuator this weekend on my rear tiller and it works
great! Basically I removed all the et lift assembly stuff, i.e.
motor and strap, down to the actual rear mounting bracket. The
actuator mounts directly to the upper pin assembly of the rear bracket,
with the end mounted to the tiller pin bracket. It does not require
the chain to support the tiller, nor any straps that were crummy and
under powered to say the least. The actuator I use is a Jack
Venture 18" unit, that is powered by 36 volt from the aux power
plug, through a dpdt/switch on tractor firewall. The actuator arm
is rated for moving up to 800 lbs and easily lifts and lowers the heavy
tiller on back of tractor. I used this same unit on the front of
tractor to lift my modified dozer blade with great success. In fact
I like these units so well, that I just ordered another one on ebay, so
that I can leave both of them on the tractor, without having to move them
from front to rear, etc.. I am going to wire two power
receptacles, one in front and one in back, on tractor that I can plug
unit(s) into as needed. The only down side that I have found with
these actuators is that they are slow in operation, but who cares.
"No more lift strap problems." Do a search on ebay for
satellite actuators to see what is available. Got mine for $39.95 -
sweet!
-
- Bob
-
-
-
-
Bob Kleinbrahm
- Senior Network Engineer
- First Republic Bank
- San Francisco, CA.
- 415-288-1478
-
-
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