Note: Descriptions are shown in the official language in which they were submitted.
IMPACT APPARATUS AND IMPACT MECHANISM WITH VARIABLE PITCH SPRING
FIELD OF THE INVENTION
[0001] The present invention relates to impact apparatuses and impact
mechanisms, and more particularly to such impact mechanisms and impact
apparatuses that are efficient at producing impact torque and impact force.
BACKGROUND OF THE INVENTION
[0002] Impact apparatuses are used to forcefully turn threaded fasteners
that are
otherwise difficult to turn. Difficulty in turning threaded fasteners is
typically encountered
when driving them a substrate such as concrete, but can be encountered in many
other
situations, especially in the construction industry.
[0003] It can therefore be seen that to some degree, the effectiveness of
an
impact apparatus is directly related to the torque supplied by the impact
mechanism
therewithin and indirectly by the drive motor, such as an electric drill.
Indeed, for years,
the entire industry has sought to develop better impact devices by increasing
the torque
of the drive motor, and by increasing the spring constant of the power spring,
which is
typically, a coil spring. However, through experimentation by the present
inventor, it has
been found that in order to achieve desired impact effects, the overall design
of the
Date Recue/Date Received 2020-11-12
spring is much more important than initially realized and more important than
is
understood in the industry.
[0004] For instance, in impact apparatuses having an adjustable range of
impact
torque settings, the conventional wisdom of increasing the spring constant of
the power
spring to achieve greater impact torque is counterproductive in some ways.
Adjusting to
a desired low impact torque, which would typically be used for advancing small
threaded fasteners into a substrate, is very difficult. It is very common when
using an
impact device to drive small threaded fasteners to over-torque them and place
too high
a tensile load on fasteners such as to fatigue the metal and eliminate its
clamp capacity
and sheer force resistance, and even to cause the threaded fasteners from
breaking
during installation.
[0005] It is an object of the present invention to provide a rotationally
operable
impact apparatus and impact mechanism that provide a high impact torque.
[0006] It is an object of the present invention to provide a rotationally
operable
impact apparatus and impact mechanism that provide a low impact torque.
[0007] It is an object of the present invention to provide a rotationally
operable
impact apparatus and impact mechanism that provide both a high impact torque
and a
low impact torque.
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Date Recue/Date Received 2020-11-12
[0008]
It is an object of the present invention to provide a rotationally operable
impact apparatus and impact mechanism that are readily adjustable to thereby
provide
a range of impact torque settings.
[0009]
It is an object of the present invention to provide a rotationally operable
impact apparatus and impact mechanism that are accurately adjustable to
throughout a
range of impact torque settings.
[00010]
It is an object of the present invention to provide a rotationally operable
impact apparatus and impact mechanism that permit setting to a predetermined
torque
such that threaded fasteners can be properly installed in order to meet
specified
standards.
[00011]
It is an object of the present invention to provide a rotationally operable
impact apparatus and impact mechanism that preclude threaded fasteners from
being
driven too far into a substrate.
[00012]
It is an object of the present invention to provide a rotationally operable
impact apparatus and impact mechanism that preclude threaded fasteners from
breaking during installation.
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Date Recue/Date Received 2020-11-12
[00013] It is an object of the present invention to provide a rotationally
operable
impact apparatus and impact mechanism that is operatively engageable with the
chuck
of an electric drill or the like, which impact apparatus and impact mechanism
provide a
high impact torque.
[00014] It is an object of the present invention to provide a rotationally
operable
impact apparatus and impact mechanism that are operatively engageable with the
chuck of an electric drill or the like, which impact apparatus and impact
mechanism
provide a low impact torque.
[00015] It is an object of the present invention to provide a rotationally
operable
impact apparatus and impact mechanism that are operatively engageable with the
chuck of an electric drill or the like, which impact apparatus and impact
mechanism
provide a high impact torque and a low impact torque.
[00016] It is an object of the present invention to provide a rotationally
operable
impact apparatus and impact mechanism that are operatively engageable with the
chuck of an electric drill or the like, which impact apparatus and impact
mechanism are
readily adjustable to thereby provide a range of impact torque settings.
[00017] It is an object of the present invention to provide a rotationally
operable
impact apparatus and impact mechanism that are operatively engageable with the
- 4 -
Date Recue/Date Received 2020-11-12
chuck of an electric drill or the like, which impact apparatus and impact
mechanism are
accurately adjustable to throughout a range of impact torque settings.
[00018]
It is an object of the present invention to provide a rotationally operable
impact apparatus and impact mechanism that are operatively engageable with the
chuck of an electric drill or the like, which impact apparatus and impact
mechanism
permit setting to a predetermined torque such that threaded fasteners can be
properly
installed in order to meet specified standards.
[00019]
It is an object of the present invention to provide a rotationally operable
impact apparatus and impact mechanism that are operatively engageable with the
chuck of an electric drill or the like, which impact apparatus and impact
mechanism
preclude threaded fasteners from being driven too far into a substrate.
[00020]
It is an object of the present invention to provide a rotationally operable
impact apparatus and impact mechanism that are operatively engageable with the
chuck of an electric drill or the like, which impact apparatus and impact
mechanism
preclude threaded fasteners from breaking during installation.
- 5 -
Date Recue/Date Received 2020-11-12
SUMMARY OF THE INVENTION
[00021]
In accordance with one aspect of the present invention there is disclosed
a novel rotationally operable impact apparatus comprising a main body member,
a drive
member operatively mounted on the main body member to be rotationally operable
about a drive axis, an output member having a main body portion and an anvil
portion
with an anvil lobe having a hammer-receiving surface and a drive-facing
surface, and
operatively mounted on the main body member for rotation about an output axis,
and a
hammer member having a hammer lobe with an anvil-impacting surface and an
anvil-
facing surface, and mounted in rotatable and sliding relation on one of the
drive member
and the output member for co-operative rotational and sliding movement with
respect to
the drive member and the output member between an anvil contact position
whereat the
anvil-impacting surface of the hammer lobe forcefully contacts the hammer-
receiving
surface of the anvil lobe and a released position whereat the hammer lobe
moves
longitudinally off and rotationally past the hammer-receiving surface of the
anvil lobe.
There is a spring means operatively interconnected between the drive member
and the
hammer member for biasing the hammer member to the anvil contact position. The
spring comprises variable pitch spring having at least one smaller pitch coil
and at least
one larger pitch coil. There is a guide means for guiding the hammer member
between
the anvil contact position and the released position when the drive member is
rotated
with respect to the output member by the spring means. In use, rotation of the
drive
member about the drive axis causes potential energy to be stored in the spring
means,
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Date Recue/Date Received 2020-11-12
whereat the hammer member is forced by the spring means longitudinally over
and
rotationally past the anvil lobe through its released position, to then be
forcefully
propelled by the spring means and the rotation of the drive member to impact
on the
hammer-receiving surface of the anvil portion, whereat force is transmitted
from the
hammer member to the anvil portion so as to create a moment about the output
axis,
thus urging the output member to forcefully rotate about the output axis.
[00022]
In accordance with one aspect of the present invention there is disclosed
a novel rotationally operable impact mechanism comprising a drive member
rotationally
operable about a drive axis and an output member having a main body portion,
an anvil
portion with an anvil lobe having a hammer-receiving surface and a drive-
facing surface,
and operatively interconnected with respect to the drive member for rotation
about an
output axis, and a hammer member having a hammer lobe with an anvil-impacting
surface and an anvil-facing surface, and mounted in rotatable and sliding
relation on
one of the drive member and the output member for co-operative rotational and
sliding
movement with respect to the drive member and the output member between an
anvil
contact position whereat the anvil-impacting surface of the hammer lobe
forcefully
contacts the hammer-receiving surface of the anvil lobe and a released
position whereat
the hammer lobe moves longitudinally off and rotationally past the hammer-
receiving
surface of the anvil lobe. There is a spring means operatively interconnected
between
the drive member and the hammer member for biasing the hammer member to the
anvil
contact position. The spring comprises variable pitch spring having at least
one smaller
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Date Recue/Date Received 2020-11-12
pitch coil and at least one larger pitch coil. There is a guide means for
guiding the
hammer member between the anvil contact position and the released position
when the
drive member is rotated with respect to the output member by the spring means.
In
use, rotation of the drive member about the drive axis causes potential energy
to be
stored in the spring means, whereat the hammer member is forced by the spring
means
longitudinally over and rotationally past the anvil lobe through its released
position, to
then be forcefully propelled by the spring means and the rotation of the drive
member to
impact on the hammer-receiving surface of the anvil portion, whereat force is
transmitted from the hammer member to the anvil portion so as to create a
moment
about the output axis, thus urging the output member to forcefully rotate
about the
output axis.
[00023] In accordance with one aspect of the present invention there is
disclosed
a novel rotationally operable impact apparatus comprising a housing, a drive
member,
an output member, a hammer member, spring means comprising a variable pitch
spring, and guide means.
[00024] In accordance with one aspect of the present invention there is
disclosed
a novel rotationally operable impact mechanism comprising a drive member, an
output
member, a hammer member, spring means comprising a variable pitch spring, and
guide means.
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Date Recue/Date Received 2020-11-12
[00025] Other advantages, features and characteristics of the present
invention,
as well as methods of operation and functions of the related elements of the
structure,
and the combination of parts and economies of manufacture, will become more
apparent upon consideration of the following detailed description and the
appended
claims with reference to the accompanying drawings, the latter of which is
briefly
described herein below.
BRIEF DESCRIPTION OF THE DRAWINGS
[00026] The novel features which are believed to be characteristic of the
impact
apparatus and impact mechanism according to the present invention, as to its
structure,
organization, use and method of operation, together with further objectives
and
advantages thereof, will be better understood from the following drawings in
which a
presently preferred embodiment of the invention will now be illustrated by way
of
example. It is expressly understood, however, that the drawings are for the
purpose of
illustration and description only and are not intended as a definition of the
limits of the
invention. In the accompanying drawings:
[00027] Figure 1 is a perspective view from the front of the illustrated
embodiment
of the impact apparatus and impact mechanism according to the present
invention;
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Date Recue/Date Received 2020-11-12
[00028] Figure 2 is a perspective view from the rear of the illustrated
embodiment
of the impact apparatus and impact mechanism of Figure 1;
[00029] Figure 3 is a side elevational view of the illustrated embodiment
of the
impact apparatus and impact mechanism of Figure 1;
[00030] Figure 4 is a front end elevational view of the illustrated
embodiment of the
impact apparatus and impact mechanism of Figure 1;
[00031] Figure 5 is a cross-sectional side elevational view of the
illustrated
embodiment of the impact apparatus and impact mechanism of Figure 1, taken
along
section line 5-5 of Figure 4;
[00032] Figure 6 is a perspective view of the drive member of the
illustrated
embodiment of the impact apparatus and impact mechanism of Figure 1;
[00033] Figure 7 is a side elevational view of the drive member of the
illustrated
embodiment of the impact apparatus and impact mechanism of Figure 1;
[00034] Figure 8 is a top plan view of the drive member of the illustrated
embodiment of the impact apparatus and impact mechanism of Figure 1;
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Date Recue/Date Received 2020-11-12
[00035] Figure 9 is a front end view of the drive member of the
illustrated
embodiment of the impact apparatus and impact mechanism of Figure 1;
[00036] Figure 10 is a back end view of the drive member of the
illustrated
embodiment of the impact apparatus and impact mechanism of Figure 1;
[00037] Figure 11 is a cross-sectional side elevational view of the drive
member of
the illustrated embodiment of the impact apparatus and impact mechanism of
Figure 1,
taken along section line 11-11 of Figure 8;
[00038] Figure 12 is a perspective view of the output member of the
illustrated
embodiment of the impact apparatus and impact mechanism of Figure 1;
[00039] Figure 13 is a left side elevational view of the output member of
the
illustrated embodiment of the impact apparatus and impact mechanism of Figure
1;
[00040] Figure 14 is a right side elevational view of the output member of
the
illustrated embodiment of the impact apparatus and impact mechanism of Figure
1;
[00041] Figure 15 is a front end view of the output member of the
illustrated
embodiment of the impact apparatus and impact mechanism of Figure 1;
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Date Recue/Date Received 2020-11-12
[00042] Figure 16 is a back end view of the output member of the
illustrated
embodiment of the impact apparatus and impact mechanism of Figure 1;
[00043] Figure 17 is a cross-sectional side elevational view of the output
member
of the illustrated embodiment of the impact apparatus and impact mechanism of
Figure
1, taken along section line 17-17 of Figure 13;
[00044] Figure 18 is a perspective view from the front of the hammer
member of
the illustrated embodiment of the impact apparatus and impact mechanism of
Figure 1;
[00045] Figure 19 is a perspective view from the back of the hammer member
of
the illustrated embodiment of the impact apparatus and impact mechanism of
Figure 1;
[00046] Figure 20 is a side elevational view of the hammer member of the
illustrated embodiment of the impact apparatus and impact mechanism of Figure
1;
[00047] Figure 21 is a front end view of the hammer member of the
illustrated
embodiment of the impact apparatus and impact mechanism of Figure 1;
[00048] Figure 22 is a back end view of the hammer member of the
illustrated
embodiment of the impact apparatus and impact mechanism of Figure 1;
- 12 -
Date Recue/Date Received 2020-11-12
[00049] Figure 23 is a cross-sectional side elevational view of the hammer
member of the illustrated embodiment of the impact apparatus and impact
mechanism
of Figure 1, taken along section line 23-23 of Figure 21;
[00050] Figure 24 is a perspective view from the front of the housing of
the
illustrated embodiment of the impact apparatus and impact mechanism of Figure
1;
[00051] Figure 25 is a perspective view from the back of the housing of
the
illustrated embodiment of the impact apparatus and impact mechanism of Figure
1;
[00052] Figure 26 is a side elevational view of the housing of the
illustrated
embodiment of the impact apparatus and impact mechanism of Figure 1;
[00053] Figure 27 is a front end view of the housing of the illustrated
embodiment
of the impact apparatus and impact mechanism of Figure 1;
[00054] Figure 28 is a back end view of the housing of the illustrated
embodiment
of the impact apparatus and impact mechanism of Figure 1;
[00055] Figure 29 is a cross-sectional side elevational view of the
housing of the
illustrated embodiment of the impact apparatus and impact mechanism of Figure
1,
taken along section line 29-29 of Figure 26;
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Date Recue/Date Received 2020-11-12
[00056] Figure 30 is a perspective view from the front of the back end
wall of the
housing of the illustrated embodiment of the impact apparatus and impact
mechanism
of Figure 1;
[00057] Figure 31 is a perspective view from the back of the back end wall
of the
housing of the illustrated embodiment of the impact apparatus and impact
mechanism
of Figure 1;
[00058] Figure 32 is a front end view of the back end wall of the housing
of the
illustrated embodiment of the impact apparatus and impact mechanism of Figure
1;
[00059] Figure 33 is a back end view of the back end wall of the housing
of the
illustrated embodiment of the impact apparatus and impact mechanism of Figure
1;
[00060] Figure 34 is a cross-sectional side elevational view of the back
end wall of
the housing of the illustrated embodiment of the impact apparatus and impact
mechanism of Figure 1, taken along section line 34-34 of Figure 33;
[00061] Figure 35 is a cross-sectional side elevational view of the back
end wall of
the housing of the illustrated embodiment of the impact apparatus and impact
mechanism of Figure 1, taken along section line 35-35 of Figure 33;
- 14 -
Date Recue/Date Received 2020-11-12
[00062] Figure 36 is a perspective view from the front of the annular main
body
member of the illustrated embodiment of the impact apparatus and impact
mechanism
of Figure 1;
[00063] Figure 37 is a front end view of the annular main body member of
the
illustrated embodiment of the impact apparatus and impact mechanism of Figure
1;
[00064] Figure 38 is a back end view of the annular main body member of
the
illustrated embodiment of the impact apparatus and impact mechanism of Figure
1;
[00065] Figure 39 is a cross-sectional side elevational view of the
annular main
body member of the illustrated embodiment of the impact apparatus and impact
mechanism of Figure 1, taken along section line 39-39 of Figure 38;
[00066] Figure 40 is a side elevational view of the variable pitch spring
used in the
rotationally operable impact apparatus and impact mechanism of Figure 1, with
the
variable pitch spring at its full length;
[00067] Figure 41 is a side elevational view of the variable pitch spring
used in the
rotationally operable impact apparatus and impact mechanism of Figure 1, with
the
variable pitch spring at its compressed length;
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Date Recue/Date Received 2020-11-12
[00068] Figure 42 is a cross-sectional side elevational view similar to
Figure 5, one
hammer lobe is shown in the anvil contact position, whereat the anvil-
impacting surface
of each of the hammer lobes forcefully contacts the hammer-receiving surface
of the
corresponding anvil lobe; and,
[00069] Figure 43 is a cross-sectional side elevational view similar to
Figure 42,
but with the one hammer lobe shown in the released position, whereat the anvil-
impacting surface of each of the hammer lobes moves longitudinally off and
rotationally
past the hammer-receiving surface of the corresponding anvil lobe.
DETAILED DESCRIPTION OF THE ILLUSTRATED EMBODIMENTS
[00070] Reference will now be made to Figures 1 through 43, which show an
illustrated embodiment of the impact apparatus according to the present
invention, as
indicated by general reference numeral 20, and impact mechanism according to
the
present invention, as indicated by general reference numeral 21. The impact
mechanism 21 is part of an impact apparatus 20, with the housing 80
additionally being
part of the impact apparatus 20. The impact apparatus 20 is for use with a
drive motor
(not specifically shown), such as the drive motor of an electric drill (not
specifically
shown). Any other suitable drive mechanism could be used.
- 16 -
Date Recue/Date Received 2020-11-12
[00071] In brief, the impact apparatus 20 comprises the impact mechanism
21, a
main body member that in the illustrated embodiment comprises a housing 80, a
drive
member 30 that in the illustrated embodiment comprises a drive shaft, an
output
member 40, a hammer member 50, a spring means 70 and a guide means 60.
[00072] The main body member, as illustrated, comprises a cylindrically-
shaped
housing 80 extending between a drive end 80a and an output end 80b. There is a
drive-end opening 83a for receiving the drive shaft 30 therethrough and an
output-end
opening 83b for receiving the output member 40 therethrough.
[00073] The housing 80 substantially surrounding the drive member 30
forwardly
of the chuck-engageable portion 32, the anvil portion 44 of the output member
40, the
hammer member 50, and the variable pitch spring 70. The housing 80 comprises
an
annular main body portion 82 terminating forwardly in a front wall portion 84,
and
terminating rearwardly in a rear opening 85. There is also a back end wall 86
removably
and replaceably mountable on the annular main body portion 82 of the housing
80. The
back end wall 86 is retained in place by threaded fasteners 81 (only one
shown) that
extend through apertures 81a in the back end of the annular main body portion
82 of the
housing 80 and threadibly engage co-operating apertures 86b in the end cap 86.
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Date Recue/Date Received 2020-11-12
[00074] The drive shaft 30 is engageable a rotatable output, namely the
chuck of
an electric drill. The chuck-engageable back end portion 32 of the drive shaft
30 is
preferably hexagonally shaped, or of any other suitable shape, for secure
engagement
into the chuck of the electric drill for rotation therewith. The chuck is
rotationally driven
by the drive motor of the electric drill for rotation therewith about a drive
axis "D" about
which the drive shaft 30 rotates. The drive shaft 30 defines the drive axis
"D" and
operatively carries a hammer member 50 and the output member 40 as will be
described in greater detail subsequently. Further, the drive member is
operatively
mounted on the main body member so as to be rotationally operable about the
drive
axis "D".
[00075] The output member 40 extends between an impact receiving end 40a
and
an output end 40b and has a tool-receiving portion 46 at the output end 40b.
The
output member has a main body portion 42 and an anvil portion 44 disposed at
the
impact receiving end 40a. The anvil portion 44 has at least one anvil lobe,
and in the
illustrated embodiment, has a first anvil lobe 44a and a second anvil lobe
44b. Each of
the anvil lobes 44a,44b has a hammer-receiving surface 45a and a drive-facing
surface
45b. The anvil portions 44a,44b are securely attached to the main body portion
42 for
co-rotation with the main body portion 42. The tool-receiving portion 46 is
securely
attached to the main body portion 42 for co-rotation with the main body
portion 42.
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Date Recue/Date Received 2020-11-12
[00076] The output member is operatively mounted on the main body member,
namely the housing 80, for rotation about an output axis "0". Further, the
output
member 40 is operatively interconnected with respect to the drive member 30
for
rotation about the output axis "0".
[00077] As can be seen in the Figures, the drive member 30 is disposed
immediately rearwardly of the output member 40.
[00078] The impact mechanism 20 further comprises an enlarged stop member
38
disposed on the front end of the drive member 30 to limit the relative
longitudinal
movement of the drive member 30 and the output member 40 with respect to each
other. Preferably, the enlarged stop member 38 is welded to the very front end
of the
drive member 30, for purposes of strength and rigidity, after the impact
mechanism 20 is
assembled, or at least after the drive member 30 has been inserted into the
output
member 40. The enlarged stop member 38 is shown separated from the drive
member
30 in Figures 6 through 11.
[00079] As can be best seen in Figures 12 through 17, the anvil portion 44
is
integrally formed with the output member 40. Preferably, the first and second
anvil lobes
44a,44b are disposed at the back end of the tool bit retaining member 40. Each
of the
first and second anvil lobes 44a,44b projects radially outwardly from the main
body
portion 42 of the output member 40.
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Date Recue/Date Received 2020-11-12
[00080] The hammer member 50 preferably comprises an annular main body 52
and at least one hammer lobe 54 projecting forwardly from the annular main
body 52. In
the first preferred embodiment, as illustrated, the at least one hammer lobe
54
comprises a first hammer lobe 54a and a second hammer lobe 54b projecting
forwardly
from the annular main body 52. The annular main body 52 and the first and
second
hammer lobes 54a,54b are integrally formed one with the others for reasons of
ease of
manufacturing and structural strength and rigidity. Preferably, the hammer
member 50
is more massive than the output member 40, in order to be able to impart
sufficient
energy to the output member 40 when the hammer member 50 impacts the output
member 40.
[00081] The hammer member 50 has a hammer lobe, and more specifically a
first
hammer lobe 54a and a second hammer lobe 54b, with an anvil-impacting surface
55a,55b and an anvil-facing surface 56a,56b. The hammer member 50 mounted in
rotatable and sliding relation on one of the drive member 30 and the output
member 40
for co-operative rotational and sliding movement with respect to the drive
member 30
and the output member 40 between an anvil contact position, as shown in
Figures 5 and
42, and a released position, as shown in Figure 43. In the illustrated
embodiment, the
hammer member is mounted in rotatable and sliding relation on the drive
member, as
can best be seen in Figure 5.
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Date Recue/Date Received 2020-11-12
[00082] In the anvil contact position, as shown in Figure 42, the anvil-
impacting
surface of each of the hammer lobes 54a,54b forcefully contacts the hammer-
receiving
surface of the corresponding anvil lobe 44a,44b (only anvil-impacting surface
and
hammer lobe 54a can be seen in Figure 42). In the released position, as shown
in
Figure 43, each of the hammer lobes 54a,54b moves longitudinally off and
rotationally
past the hammer-receiving surface of the corresponding anvil lobe (only anvil-
impacting
surface and hammer lobe 54a can be seen in Figure 42).
[00083] The spring means comprises a coil spring 70 and is operatively
interconnected between the drive member 30 and the hammer member 50 for
biasing
the hammer member 50 to the anvil contact position. The spring 70 comprises
variable
pitch spring, also known as a variable rate spring or a progressive pitch
spring, and has
at least one smaller pitch coil 71a and at least one larger pitch coil 71b.
The variable
pitch spring 70 is shown in an extended configuration in Figure 40 and in a
compressed
configuration in Figure 41.
[00084] In the illustrated embodiment of the variable pitch spring 70, the
ratio of
the smallest pitch in the at least one smaller pitch coil 71a to the largest
pitch in the at
least one larger pitch coil 71b is at least 1:2. The at least one smaller
pitch coil 71a
comprises a first smaller pitch coil section 71c and a second smaller pitch
coil section
71d, and the at least one larger pitch coil comprises a first larger pitch
coil section 71e.
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Date Recue/Date Received 2020-11-12
The first larger pitch coil section 71e is disposed between the first smaller
pitch coil
section 71c and the second smaller pitch coil section 71d.
[00085] Also, in the illustrated embodiment of the variable pitch spring
70, the
diameter of the wire forming the spring is between about 0.125 inches and
about 0.162
inches, the length of the spring is between about 1.0 inches and 3.0 inches,
and the
diameter of the spring is between about 1.0 inches and 1.5 inches.
[00086] In the present invention, the guide means 60 is for guiding the
hammer
member 50 between the anvil contact position and the released position when
the drive
member 30 is rotated with respect to the output member 40 by the variable
pitch spring
70.
[00087] The guide means 60 is for moving the hammer member 50 between the
anvil contact position and the released position when the drive member 30 is
rotated
with respect to the tool bit retaining member 40. The guide means 60 is
disposed on the
forward cylindrical portion 34 and comprises first and second "V"-shaped
grooves
62a,62b in the outer surface 31 of the drive member 30, a co-operating first
and second
races 51a,51b in an interior surface 53 of the hammer member 50. A first ball
bearing
64a is operatively engaged in the first "V"-shaped groove 62a and the first
race 51a.
Similarly, a second ball bearing 64b is operatively engaged in the second "V"-
shaped
groove 62b and the second race 51b. As can be seen in Figures 4 through 7, the
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Date Recue/Date Received 2020-11-12
hammer member 50 surrounds the drive member 30 and is retained in space
relation
from the drive member 30 by the first and second ball bearings 64a,64b.
[00088] The impact mechanism 20 further comprises a selectively adjustable
spring compression mechanism, as indicated by the general reference numeral
90, for
permitting selective compression of the variable pitch spring 70. The
selectively
adjustable spring compression mechanism 90 comprises an annular main body
member
92 having an internal right-hand thread 94 and a reduced forward portion 96
and an
annular lip 97. The annular main body member 92 is threadibly engaged on a co-
operating external right-hand thread 38 on the drive engaging member 30.
[00089] The annular main body member 92 also has a manually grippable
portion
98 that extends through a co-operating aperture in the back end wall 86 of the
housing
80 such that the manually grippable portion 98 is disposed exteriorly to the
housing 80.
When the manually grippable portion 98 is rotated in a clockwise direction,
the annular
main body member 92 is advanced forwardly along the drive member 30, thus
further
compressing the variable pitch spring 70. Conversely, when the manually
grippable
portion 98 is rotated in a counter-clockwise direction, the annular main body
member 92
is retracted rearwardly along the drive member 30, thus permitting expansion
of the
variable pitch spring 70.
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Date Recue/Date Received 2020-11-12
[00090] In use, rotation of the drive shaft 30 about the drive axis "D"
causes
potential energy to be stored in the variable pitch spring 70. The first
hammer lobe 54a
and a second hammer lobe 54b of the hammer member 50 are forced by the
variable
pitch spring 70 longitudinally over and rotationally past the anvil lobes
44a,44b
respectively, through its released position, to then be forcefully propelled
by the variable
pitch spring 70 and the rotation of the drive member 30 to impact on the
hammer-
receiving surface 45a,45b of the anvil portion 44. Force is transmitted from
the hammer
member 50 to the anvil portion 44 so as to create a moment about the output
axis "0",
thus urging the output member 40 to forcefully rotate about the output axis
"0".
[00091] It has been found that with the impact apparatus 20 and impact
mechanism 21 according to the present invention, the impact torque that is
produced is
significantly greater than with a prior art impact apparatus and impact
mechanism of
about the same size and weight and other similar characteristics, using the
same
electric drill for rotational power.
[00092] As can be understood from the above description and from the
accompanying drawings, the present invention provides an impact apparatus that
is
operatively engageable with the chuck of an electric drill or the like, which
impact
apparatus provides a high impact torque, provides a low impact torque,
provides both a
high impact torque and a low impact torque, is readily adjustable to thereby
provide a
range of impact torque settings, is accurately adjustable to throughout a
range of impact
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Date Recue/Date Received 2020-11-12
torque settings, permits setting to a predetermined torque such that threaded
fasteners
can be properly installed in order to meet specified standards, precludes
threaded
fasteners from being driven too far into a substrate, and precludes threaded
fasteners
from breaking during installation, all of which features are unknown in the
prior art.
[00093]
Other variations of the above principles will be apparent to those who are
knowledgeable in the field of the invention, and such variations are
considered to be
within the scope of the present invention. Further, other modifications and
alterations
may be used in the design and manufacture of the impact mechanism of the
present
invention without departing from the spirit and scope of the accompanying
claims.
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Date Recue/Date Received 2020-11-12
