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Nancy E. Laurie
02-25-1999, 12:19 AM
Dear colleagues:

A few weeks ago I posted a message requesting information on mini load
cells. The response was magnificent. Below is my original message and a
summary of the responses. Thanks to all those who replied.

Regards,

Nancy Laurie
Laboratory Manager
Human Performance Laboratory
University of Massachusetts
Amherst, MA 01003


>Dear colleagues:
>I would like to measure force (Fz, Fy and Fx) at the interface between
a
>hammer handle and the palm. I have heard about mini load cells that
>could possibly be used for this application. Does anyone know who makes

>this type of equipment? I welcome any comments, suggestions or ideas
>you may have on approaching this problem. I will post a summary of the

>responses.
>
>
>



We use a three-axis force/torque sensor from ATI Industrial Automation
called the NANO 17. It has performed very well and ATI is a pleasure to
deal with.

ATI Industrial Automation
Garner, NC, USA
919 772 0115
info@ati-ia.com

Warren Grill
---------------------------------------------------------------
Omega (1-800-TC-OMEGA) carries subminiature load cells, as does Sensotec

(800-848-6564). I'm looking forward to your summary however, as any
other
options that are less expensive than these (the cells tend to be pretty
steep) would be marvelous.

Regards,
Adam Arabian
Masters Student
Michigan State University Dpt. of Mechanical Engineering
---------------------------------------------------------------

Nancy,

I'd suggest contacting Novel Electronics in St Paul, MN. Ask Susan or
Kevin
about the glove their company has come up with. At present it is a
pressure
measurement device but they have been working on seperating the
individual
force vectors.

Their number is 651-221-0505

Good Luck,

Mic
---------------------------------------------------------------

Nancy E. Laurie,

A collaborated study at University of Washington, Seattle, between the

Department of Electrical Engineering and the Department of Surgery, is
including measurements of multi-axis forces/torque signature (Fx, Fy,
Fz, Tx, Ty, Tz) at the interface between the surgeon hand and an
endoscopic tool during minimally invasive surgery. This measurements
are performed by using ATI force/torque mini sensor
(http://www.ati-ia.com) which is inserted into the outer tube of the
endoscope tool. An alternative sensor for your application might be a
sensor capable of measuring the same thing, which is manufactured by
JR3 (http://www.jr3.com).
You may visit the BioRobotics Lab Web site for learning more about
this study http://rcs.ee.washington.edu/BRL/

Good Luck

Jacob Rosen

---------------------------------------------------------------

Nancy,
check PCB Piezotronics.
Thanks
Nick

---------------------------------------------------------------

Hey Nancy,

I would contact Microstrain up in Vermont. We are using mini strain
gauges that are smaller than half a penny. They are really good
technically and if you need a name, look for Steve Arms. Good luck...

Andrew Mahar
---------------------------------------------------------------

You can use transducers going directly to the APAS system and you will
have
the forces, EMG and Kinematics all synchronized.
See at: http://www.arielweb.com

---------------------------------------------------------------

Dear Laurie:

I don't know anything about the cells, but could you please post the
results
to your question?

Thanks,

Beverly Burke RN
Movement Systems

Certified Movement Analyst
Certified Industrial Ergonomist

503-636-4203

Standard disclaimers apply.
---------------------------------------------------------------


Check out Assurance Technologies
(http://www.ati.thomasregister.com/olc/ati/axis.htm). They make a
6-axis
force transducer called the Nano that's about the diameter of a dime and

about 1 cm thick. The only problem with it is that it's about US$6000!

Cheers,

Tony Hodgson
UBC Mechanical Engineering

---------------------------------------------------------------

AMTI and Bertec are the only ones I know of who make 3 axis force load
cells, but these things are huge 1.4 Kg. But they may be able to advise
you
on where to go for small ones.

Kistler and Sensotec also do very small load cells but I haven't found
anything with 3 axis (compression only)


http://www.designinfo.com/

This web address can do a product search based on your spec. Try it out
and
see what it comes up with. If nothing else it is a good source of
companies
and addresses.

Let me know if you find anything,
Regards
Nicola Taylor
Institute of Materials Research and Engineering
Block S7, Level 3
National University of Singapore
10, Kent Ridge Crescent
Singapore 119260
Tel: (65) 874 8197
Fax:(65) 872 0785
www.imre.org.sg
---------------------------------------------------------------

Dear Nancy Laurie,

Consult the following site :

PCB Piezotronics Inc.
http://www.pcb.com/products/new/pfsnew260a11.html

I don't know if this product will be adapted for your project, but
perhaps
you get some additional information with this company.
Good luck in your work.

Best Regards,

Wagner de Godoy
Gait Laboratory
AACD - http://www.aacd.org.br
Brazil
---------------------------------------------------------------

NK Biotechnology in Minneapolis/St.Paul area of Minnesota makes a 3 DOF
load cell 1" diam used for patellofemoral forces in TKA studies in the
past. It would probably require modification for your application, but
the performance of the device, based on previous experience, would be
very
good and be NIST traceable.

Good Luck.

//////////////////////////////////\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\
Steven E. Irby Telephone: (507)284-1423
Biomechanics Laboratory FAX: (507)284-5392
Mayo Clinic irby.steven@mayo.edu
Guggenheim 128
200 First Street SW
Rochester, MN, 55905
\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\///////////////////////////////////
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Nancy,

There has been some work at the University of Kent here in the UK on
piezoelectric transducers for the measurement of vertical and shear
forces between the
skin and the insoles of shoes. The URL is
http://eleceng.ukc.ac.uk/research/medical/podiatr.html

Good luck!

Andrew

Dr Andrew New
Department of Design & Engineering
School of Design & Communication Systems
Anglia Polytechnic University
Chelmsford
Essex CM1 1LL
Tel 01245 493131 x 3316
Fax 01245 252646
World Wide Web http://www.isc.anglia.ac.uk/~bioweb/
---------------------------------------------------------------

Laurie,

I know Jesus Dapena did some work in the early 80's looking at the
force developed in the hammer cable. Whether he approached the force
deeloped in the handle problem I don't know, but he may be worth a
try.

Best of luck,


Calvin Morriss
UK Athletics Biomechanics Coordinator
Manchester Metropolitan University
Crewe and Alsager Faculty
Alsager
S-O-T. ST7 2HL
UK.
0161 247 5573 (w)
0956 922 832 (m)
0161 247 6375 (f)
---------------------------------------------------------------

Dear Nancy,

We are currently developing a triaxial force transducer. This
measures 1x1x0.3 cm and should be able to measure hammer handle-palm
forces. We have some experience with Mr Paul McArthur, plastic
surgeon at the Morriston Hospital, Swansea, using similar vertical
force transducers for monitoring hand grip forces before and after
reconstructive surgery.

The transducer development is being carried out under sponsorhip from
Kistler Instruments. It is also possible that they migh have a
commercial transducer that could meet your need.

Thus the application of thetransducer is stil a d R&D issue rather
than a commercial buy.

If you think that what we are doing might be of long term interest
please let me know.

Regards


Matthew Pepper
--------------------------------------------------
m.g.pepper@ukc.ac.uk

Dr Matthew Pepper
Electronic Engineering Department
University of Kent
Canterbury CT2 7NT
Kent
England

Tel: 01227 823450 (direct Line)
01227 764000 Ext 3450
Fax 01227 456084
---------------------------------------------------------------

Dear Nancy,

I hope you received Dr. pepper's email by now .
You can have a look at this WEB page where the tri-axial
transducer charactristics are explained.

http://esb.purpan.inserm.fr/abs_htm/687.html

M A Razian

Medical Elec. Lab.
University of Kent
---------------------------------------------------------------

A flexible, capacitive sensor grid is available from novel, a german
company (http://novel.de, US rep is Susan Diekrager at 651-221-0505).
They
mainly sell insole sensor grids and seating mats for measuring in-shoe
plantar forces and seating pressure, respectively, but you could easily
obtain a sensor grid from them that could be wrapped around a hammer
handle. At one point, they were also working on a pressure-sensitive
glove.
The catch is that you only get normal forces. Your other choice is to
instrument the hammer or the subject with discrete sensors, but this
will
significantly alter the surface interface. The nice thing about the
novel
sensors is that they form a smooth wrap around the handle, minimizing
changes to the grip surface.

Good luck.

-- Jeff
---------------------------------------------------------------

Hello Laurie:
My suggestion would be to use a steel handled hammer
with a small (1") section of the handle near the
hand grip that has been reduced to a square
approx 3/8" to 1/2" on each side(depending on the
amount of force you intend to measure). Then by
applying strain gages directly to this area in the
proper orientation you can use slight flextion of
the hammer handle itself to measure the Forces Fx Fy Fz.
Find someone familier with applying strain gages
and get them to help you select the gages and mount them.
Sincerely
Cliff Beckett
---------------------------------------------------------------

Nancy,
Our pliance system can be used for instrumenting a hammer. The flexible

sensor matrix measures pressure distribution while gripping. If you
would
like additional information please check out our web site ( www.novel.de
)
or call (651 221-0505)
Kevin

____________________________________

Please visit novel on the web!!
http://www.novel.de
____________________________________

Kevin Ford, M.S.
Biomechanics Research
novel electronics, inc.

964 Grand Avenue
St. Paul, MN 55105

phone (651) 221-0505
fax (651) 221-0404

kevinford@novel.de

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