Clarification of Question by
googel-ga
on
29 Jun 2003 21:58 PDT
The comments:
Subject: Re: Newton's Law
From: googel-ga on 26 Jun 2003 23:52 PDT
"pneumatic wrenches"
http://www.atlascopco.com/tools/products/website.nsf/0/2cd20ab5cce54542c1256c5c002fc555/$FILE/Tightening%20technique.pdf
pages 17- 22
pages 18-19:
" The advantage of impact wrenches is that they have a very high
capacity
relative to the weight and size of the tool. As the reaction torque is
not
greater than that needed to accelerate the hammer the reaction force
transferred back to the operator is very small..."
http://www.spairtool.co.uk/pneumatic_tools/wrenches/
:
"Applications:
Excellent choice for heavy automotive and truck work such as tyre
changing, shock and spring work, farm, body shop, and front end work.
Ideal anywhere extra powerful tools are needed.
Features:
Twin dog clutch provides more power and smooth balanced blows
"
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Subject: Re: Newton's Law
From: googel-ga on 27 Jun 2003 14:57 PDT
Hi eek-ga,
What I have learned here from racecar-ga then my web-findings about
pneumatic wrenches is that
"accelerating the impact wrench (hammer) out of one's hand"
is prevented by proper limit settings, clutch/es (for decoupling)
and the small hammer-accelerating torque and force --among others
probably.
googel-ga
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Subject: Re: Newton's Law
From: googel-ga on 28 Jun 2003 08:00 PDT
To any researcher,
Please answer this question and feel free to use any of my comments
here.
http://patft.uspto.gov/netacgi/nph-Parser?Sect1=PTO2&Sect2=HITOFF&u=/netahtml/search-adv.htm&r=9&p=1&f=G&l=50&d=ptxt&S1=((wrench+AND+reaction)+AND+(force+OR+torque)).ABST.&OS=abst/(wrench+and+reaction+and+(force+or+torque))&RS=ABST/((wrench+AND+reaction)+AND+(force+OR+torque))
United States Patent 6,009,775
Inventors: Thompson; Owen R. (Louisville, KY); Weber; Edward J.
(Girard, PA); Rounds; Jerry L. (Erie, PA)
Assignee: Titan Tool Company (Fairview, PA)
2. Background of Related Art
A wrench that transfers energy stored in a flywheel to a bolt or nut
which is to be loosened is conventionally known in the automobile
lugnut removal field. U.S. Pat. No. 5,158,354 to Simonin discloses a
conventional wrench with a drive motor and flywheel that are rigidly
connected in a housing to drive an output ferrule when a spring clutch
is engaged. In operation, a user provides power to the drive motor
which causes a flywheel to rotate. Once the flywheel achieves a
predetermined speed, the user presses the output ferrule onto a lugnut
which causes a single tooth clutch plate connected to the ferrule to
collide with a mating single tooth clutch plate connected to the
flywheel. The rotational energy from the flywheel is then transferred
to the output ferrule to provide a removal force to a lugnut engaged
by the ferrule. The conventionally known wrench is designed for the
specific purpose of quickly removing a flat tire. Accordingly, the
conventional wrench is designed to be economically made with little
concern for accuracy or endurance.
Because the motor of the conventionally known flywheel wrench is
rigidly connected to the housing, a torque reaction will be
transmitted directly to the user of the device. Torque reaction is a
detrimental reverse torque which results from the elastic collision of
the clutch mechanism when the rotational energy transmitted from the
flywheel to the output ferrule is converted to a torque for removing a
fastener. Transmission of torque reaction to an operator can lead to
many undesirable health problems including nerve damage, muscle strain
and bruising. Torque reaction is especially large when the rotational
energy stored in the flywheel is not sufficient to remove the fastener
to which the output ferrule is connected. Torque reaction is also
compounded when any of the mechanisms that are rotated are not
concentric. The nature and object of conventionally known flywheel
wrenches has never demanded a strict limit to the amount of torque
reaction that is acceptable because conventionally known flywheel
wrenches are generally used in lightweight limited use applications,
such as removing a lugnut from an automobile wheel. Accordingly, the
detrimental effects of torque reaction being transmitted to an
operator are negligible in conventionally known flywheel wrenches and
do not outweigh the benefits of making the device economical and
compact.
In heavier, industrial applications, it is conventionally known to use
an impact wrench to remove fasteners. The impact wrench also suffers
from the problem of transmission of torque reaction to the operator.
In addition, the user of an impact wrench has little control over the
amount of torque that is output by the tool. Torque output from air
operated power equipment, such as an impact wrench, varies greatly
depending on the air pressure, amount of moisture in the air and the
condition of the motor itself. Furthermore, impact wrenches require a
relatively large amount of input power to achieve a given output
torque.
SUMMARY OF THE INVENTION
The present invention has been made in view of the above problems. An
object of the invention is to provide an economical and efficient
wrench that transmits little torque reaction from the output drive to
the wrench housing. Another object of the invention is to provide a
wrench that can be easily and accurately controlled to provide a
specific torque output. A further object of the invention is to
provide a wrench that can be used while suspended by a cable without
requiring the physical control of an operator during use. Yet another
object of the invention is to provide a wrench that requires a small
power input to achieve a large torque output.
According to a first aspect of the invention, there is provided a
power driven wrench in which a drive motor is located inside a
housing. An inertial mass for example, a flywheel is connected to the
drive motor such that it can be rotationally driven. An output drive
mechanism is located at an output end of the inertial mass. The
inertial mass and the drive motor are connected to the housing such
that they can rotate with respect to the housing to substantially
prevent torque reaction from being transmitted to the housing.
