U.S. patent application number 11/379877 was filed with the patent office on 2007-10-25 for vibration dampening of a power tool.
Invention is credited to Dennis W. Henry, Emile Homsi, Marianne F. Knox, Eugene L. Volynsky.
Application Number | 20070246237 11/379877 |
Document ID | / |
Family ID | 38618395 |
Filed Date | 2007-10-25 |
United States Patent
Application |
20070246237 |
Kind Code |
A1 |
Homsi; Emile ; et
al. |
October 25, 2007 |
VIBRATION DAMPENING OF A POWER TOOL
Abstract
The invention provides a power tool assembly having a motor. The
power tool assembly includes a housing having an inner surface
defining a cavity enclosing the motor. The power tool assembly also
includes a layer of polyurethane elastomer disposed on the inner
surface and extending into the cavity. The polyurethane elastomer
dampens vibration of the motor during operation of the power tool
assembly.
Inventors: |
Homsi; Emile; (Nutley,
NJ) ; Volynsky; Eugene L.; (Fort Lee, NJ) ;
Henry; Dennis W.; (Chadds Ford, PA) ; Knox; Marianne
F.; (Lincoln University, PA) |
Correspondence
Address: |
BASF AKTIENGESELLSCHAFT
CARL-BOSCH STRASSE 38, 67056 LUDWIGSHAFEN
LUDWIGSHAFEN
69056
DE
|
Family ID: |
38618395 |
Appl. No.: |
11/379877 |
Filed: |
April 24, 2006 |
Current U.S.
Class: |
173/213 |
Current CPC
Class: |
B25F 5/006 20130101 |
Class at
Publication: |
173/213 |
International
Class: |
E21B 19/16 20060101
E21B019/16 |
Claims
1. A power tool assembly comprising: a housing having an inner
surface defining a cavity; a motor disposed within said cavity of
said housing and coupled to said inner surface; and a layer of
polyurethane elastomer disposed at least partially on said inner
surface for dampening vibration of said motor during operation of
the power tool assembly.
2. A power tool assembly as set forth in claim 1 wherein said layer
of polyurethane elastomer is further defined as a layer of
microcellular polyurethane.
3. A power tool assembly as set forth in claim 1 wherein said layer
of polyurethane elastomer includes a first surface attached to said
inner surface and a second surface opposite the first surface
projecting into said cavity.
4. A power tool assembly as set forth in claim 3 wherein said
second surface of said elastomer is further defined as being spaced
from said inner surface and said motor.
5. A power tool assembly as set forth in claim 1 wherein said layer
of polyurethane elastomer covers substantially all of said inner
surface of said housing.
6. A power tool assembly as set forth in claim 6 wherein said
housing further including: a first housing shell defining a first
portion of said inner surface; and a second housing shell defining
a second portion of said inner surface with said second housing
shell being connectable to said first housing shell to define said
cavity and said layer of polyurethane elastomer disposed on both of
said first and said portions.
7. A power tool assembly as set forth in claim I wherein said
housing further including: a first housing shell defining a first
portion of said inner surface and having a plurality of first
bosses projecting from said first portion of said inner surface; a
second housing shell defining a second portion of said inner
surface and having a plurality of second bosses projecting from
said second portion of said inner surface with said second housing
shell being connectable to said first housing shell to define said
cavity and said layer of polyurethane elastomer encircling at least
one of said first and said second bosses.
8. A power tool assembly as set forth in claim 7 wherein said layer
of polyurethane elastomer encircles all of said first and second
bosses.
9. A power tool assembly as set forth in claim 1 wherein said layer
of polyurethane elastomer is discontinuous.
10. A power tool assembly as set forth in claim 9 wherein said
layer of polyurethane elastomer is further defined as a plurality
of discrete pieces spaced from one another about said inner
surface.
11. A power tool assembly as set forth in claim 1 further including
a tool member coupled to said motor and driven in motion by said
motor with said tool member selected from a group consisting of a
drill bit chuck, a saw blade and a fan.
12. A method of assembling a power tool assembly having a housing
with an inner surface, a motor, and a layer of polyurethane
elastomer, said method comprising the steps of: disposing the layer
of polyurethane elastomer on the inner surface; and enclosing the
motor within the inner surface of the housing wherein the layer of
polyurethane elastomer dampens vibration generated by the motor
during operation of the power tool assembly.
13. A method as set forth in claim 12 wherein the layer of
polyurethane elastomer includes a first surface and a second
surface opposite the first surface and wherein the step of
disposing the layer of polyurethane elastomer is further defined
as: attaching the first surface of the elastomer to the inner
surface of the housing; and exposing the second surface of the
elastomer to an interior cavity of the housing.
14. A method as set forth in claim 12 wherein the step of disposing
the layer of polyurethane elastomer is further defined as
substantially covering all of the inner surface of the housing with
the layer of polyurethane elastomer.
15. A method as set forth in claim 12 wherein the step of disposing
the layer of polyurethane elastomer is further defined as wedging
the layer of polyurethane elastomer between the motor and the inner
surface of the housing.
16. A method as set forth in claim 12 the step of disposing the
layer of polyurethane elastomer is further defined as adhering the
layer of polyurethane elastomer to the inner surface with an
adhesive.
17. A method as set forth in claim 12 wherein the step of disposing
the layer of polyurethane elastomer is further defined as
overmolding the layer of polyurethane elastomer on the inner
surface.
Description
FIELD OF THE INVENTION
[0001] The invention relates to dampening vibration associated with
a power tool.
BACKGROUND OF THE INVENTION
[0002] Power tools often generate vibration that can be transferred
the operator's hand when the tool is grasped and used. The
vibration can be unhealthy to the operator. For example, the
operator's wrist and fingers can be strained and can create a
condition known as a white finger effect. Another problem
associated with the vibration of a power tool is that vibration
makes it difficult to keep the tool in a precise position. This can
result in damaged work-pieces and can expose the operator to
injuries due to recoil and misdirected blows.
[0003] Accordingly, it would be desirable to develop a material,
for example, for dampening vibration in a power tool while not
increasing the operating temperatures of the tool or interfering
with the operation of the tool
SUMMARY OF THE INVENTION
[0004] The subject invention includes a power tool assembly having
a housing with an inner surface defining a cavity. A motor is
disposed within the cavity of the housing and coupled to the inner
surface. A layer of polyurethane elastomer is disposed at least
partially on the inner surface for dampening vibration of the motor
during operation of the power tool assembly. The subject invention
also includes a method of assembling the power tool assembly. The
method comprises the steps of: disposing the layer of polyurethane
elastomer on the inner surface and enclosing the motor within the
inner surface of the housing wherein the layer of polyurethane
elastomer dampens vibration generated by the motor during operation
of the power tool assembly.
[0005] Accordingly, the subject invention incorporates a layer of
polyurethane elastomer into the power tool for dampening vibration
of the power tool. The polyurethane elastomer, however, does not
contribute to increasing the operating temperatures of the tool and
does not interfere with the operation of the tool.
BRIEF DESCRIPTION OF THE DRAWINGS
[0006] Advantages of the present invention will be readily
appreciated as the same becomes better understood by reference to
the following detailed description when considered in connection
with the accompanying drawings wherein:
[0007] FIG. 1 is an exploded view of a power tool according to a
first exemplary embodiment of the invention;
[0008] FIG. 2 is an exploded view of a power tool according to a
second exemplary embodiment of the invention; and
[0009] FIG. 3 is an exploded view of a power tool according to a
third exemplary embodiment of the invention;
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT
[0010] A plurality of different embodiments of the invention are
shown in the Figures of the application. Similar features are shown
in the various embodiments of the invention. Similar features have
been numbered with a common reference numeral and have been
differentiated by an alphabetic designation. Also, to enhance
consistency, features in any particular drawing share the same
alphabetic designation even if the feature is shown in less than
all embodiments. Similar features are structured similarly, operate
similarly, and/or have the same function unless otherwise indicated
by the drawings or this specification. Furthermore, particular
features of one embodiment can replace corresponding features in
another embodiment unless otherwise indicated by the drawings or
this specification.
[0011] Referring now to FIG. 1, in a first exemplary embodiment of
the invention, a power tool assembly 10 includes a motor 12. The
first exemplary power tool assembly 10 is a hammer drill. The power
tool assembly 10 also includes a housing 14 having an inner surface
16 defining a cavity with the motor 12 disposed within the cavity
and coupled to the inner surface 16. The power tool assembly 10
also includes a layer of polyurethane elastomer 18 disposed at
least partially on the inner surface 16. In the embodiment of FIG.
1 the layer of polyurethane elastomer 18 covers substantially all
of the inner surface 16 of the housing 14. The polyurethane
elastomer 18 dampens vibration of the motor 12 during operation of
the power tool assembly 10.
[0012] The layer of polyurethane elastomer 18 can be engaged with
the inner surface 16 by different methods. In a first exemplary
method for assembling the power tool assembly 10, the layer of
polyurethane elastomer 18 can be disposed on inner surface 16 by
adhering the layer of polyurethane elastomer 18 to the inner
surface 16 with an adhesive. The layers of polyurethane elastomer
18 can be cut from sheets of material into any suitable
configuration. Alternatively, the layer of polyurethane elastomeric
18 may be secured to the inner surface 16 by any suitable
mechanical interlocking feature. In another exemplary method for
assembling the power tool assembly 10, the layer of polyurethane
elastomer 18 can be disposed on inner surface 16 by overmolding the
layer of polyurethane elastomer 18 on the inner surface 16. As
should be appreciated, the layer of polyurethane elastomer 18 can
be secured to the inner surface 16 by any suitable method so long
as the transmission of vibration to the layer of polyurethane
elastomer 18 is not impeded.
[0013] The first exemplary power tool assembly 10 includes a tool
member 20 coupled to the motor 12 and driven in motion by the motor
12. The first exemplary tool member 20 is a drill bit chuck.
[0014] The housing 14 preferably includes a first housing shell 22
defining a first portion 24 of the inner surface 16. The housing 14
also includes a second housing shell 26 defining a second portion
28 of the inner surface 16 with the second housing shell 26 being
connectable to the first housing shell 22 to define the cavity. A
plurality of first bosses 30, 32, 34, 36, 38, 40, 42, 44 project
from the first portion 24 of the inner surface 16 and a plurality
of second bosses 46, 48, 50, 52, 54, 56, 58, 60 project from the
second portion 28 of the inner surface 16. The layer of
polyurethane elastomer 18 preferably encircles at least one of the
first and second bosses. The various first and second bosses can be
disposed in the housing 14 to connect the first and second housing
shells 24, 26 together, to connect the motor 12 with one or both of
the first and second housing shells 24, 26, and/or to connect
support structures within the housing 14 such as the motor 12 (as
done by the boss 48) or a trigger assembly 62 for engaging the
motor 12. Hence, in one embodiment, the layer of polyurethane
elastomer 18 can be wedged between the motor 12 and the inner
surface 16 of the housing 14.
[0015] In the first exemplary embodiment of the invention, the
layer of polyurethane elastomer 18 is disposed on both of the first
portion or half 24 of the inner surface 16 and the second portion
or half 28 of the inner surface 16, including encircling all of the
first and second bosses. The layer of polyurethane elastomer 18
includes a first surface (not visible) attached to the inner
surface 16 and a second surface 64 opposite the first surface
projecting into the cavity. In other words, the second surface 64
of the elastomer 18 is spaced from both the inner surface 16 and
the motor 12, exposed within the housing 14. The layer of
polyurethane elastomer 18 can dampen vibration generated by the
motor 12 during operation without being in direct contact with the
motor 12.
[0016] The layer of polyurethane elastomer 18 of the various
embodiments of the invention is preferably a layer of microcellular
polyurethane. Cellasto.RTM. is a microcellular polyurethane that
can be used to practice the invention. Cellasto.RTM. is acquired
from the BASF, The Chemical Company. Cellasto.RTM. does not
measurably capture heat within the housing 14 such that an
operational temperature of the power tool does not increase when
the elastomer 18 is disposed therein. Hence, although the
Cellasto.RTM. preferably covers the entire inner surface 16 of the
housing 14, the motor 14 will not overheat under normal operating
conditions.
[0017] Referring now to FIG. 2, in a second exemplary embodiment of
the invention, a power tool assembly 10a includes a motor 12a. The
second exemplary power tool assembly 10a is a reciprocating saw and
includes a tool member 20a coupled to the motor 12a and driven in
motion by the motor 12a. The second exemplary tool member 20a is a
saw. The power tool assembly 10a also includes a housing 14a having
an inner surface 16a defining a cavity enclosing the motor 12a. The
power tool assembly 10a also includes a layer of polyurethane
elastomer 18a disposed at least partially on the inner surface 16a.
The polyurethane elastomer 18a dampens vibration of the motor 12a
during operation of the power tool assembly 10a. Preferably, in
this embodiment, the layer of polyurethane elastomer 18a is
discontinuous. For example, the layer of polyurethane elastomer 18a
includes a plurality of discrete pieces 66a, 68a, 70a, 72a spaced
from one another about the inner surface 16a. The discrete pieces
66a, 68a, 70a, 72a of the second exemplary embodiment of the
invention are disposed on the handle portion of the power tool
assembly 10a and can have varied thicknesses.
[0018] Referring now to FIG. 3, in a third exemplary embodiment of
the invention, a power tool assembly 10b includes a motor 12b. The
third exemplary power tool assembly 10b is a blower and includes a
tool member coupled to the motor 12b driven in motion by the motor
12b. The third exemplary tool member 20b is a fan (not visible).
The power tool assembly 10b also includes a housing 14b having an
inner surface 16b defining a cavity enclosing the motor 12b. The
power tool assembly 10b also includes a layer of polyurethane
elastomer 18b disposed on the inner surface 16b. The polyurethane
elastomer 18b dampens vibration of the motor 12b during operation
of the power tool assembly 10b.
[0019] The housing 14b includes a first housing shell 22b defining
a first portion 74b of the inner surface 16b. The first portion 74b
is less than half of the inner surface 16b. The housing 14b also
includes a second housing shell 26b connectable to the first
housing shell 22b to form the housing 14b. The second housing shell
26b defines a second portion 76b of the inner surface 16b, greater
than half of the inner surface 16b. A first plurality of bosses
30b, 32b, 34b projects from the first portion 74b of the inner
surface 16b and a second plurality of bosses 46b, 48b, 50b projects
from the second portion 76b of the inner surface 16b.
[0020] A first fastener 78b extends at least partially through the
boss 30b of the first plurality of bosses and at least partially
through the boss 46b of the second layer of bosses to connect the
first housing shell 22b with the second housing shell 26b. A first
piece 66b of the layer of polyurethane elastomer 18b encircles the
boss 30b and a second piece 68b of the layer of polyurethane
elastomer 18b encircles the boss 46b.
[0021] A second fastener 80b extends at least partially through the
boss 34b of the first plurality of bosses and at least partially
through the boss 50b of the second layer of bosses to connect the
first housing shell 22b and the second housing shell 26b with the
motor 12b. A third piece 70b of the layer of polyurethane elastomer
18b encircles the boss 34b and a second piece 72b of the layer of
polyurethane elastomer 18b encircles the boss 50b. The third and
fourth pieces 70b, 72b of the layer of polyurethane elastomer 18b
are compressed between the motor 12b and the inner surface 16b of
the housing 14b.
[0022] The invention has been described in an illustrative manner,
and it is to be understood that the terminology which has been used
is intended to be in the nature of words of description rather than
of limitation. As is now apparent to those skilled in the art, many
modifications and variations of the present invention are possible
in light of the above teachings. It is, therefore, to be understood
that within the scope of the appended claims, wherein reference
numerals are merely for convenience and are not to be in any way
limiting, the invention may be practiced otherwise than as
specifically described.
* * * * *