CA3098780A1 - Impact apparatus and impact mechanism with variable pitch spring - Google Patents

Abstract

ABSTRACT OF THE DISCLOSURE
An impact apparatus comprises a main body member, a drive member, an output member, a hammer member, a variable pitch spring having at least one smaller pitch coil and at least one larger pitch coil, and a guide means. In use, rotation of the drive member causes potential energy to be stored in the spring. The hammer member is forced by the variable pitch spring longitudinally over and rotationally past the anvil lobe through its released position, to impact the anvil portion of the output member, so as to create a moment about the output axis, thus urging the output member to forcefully rotate about the output axis. The variable pitch spring maximizes the torque created by the output member and the control of the torque.

Date Recue/Date Received 2020-11-12

Description

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.

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.

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 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.

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, 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 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.

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;

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;

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;

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;

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;

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;

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;

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.

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.

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.

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 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.

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 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.

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.

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 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.

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 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.

Date Recue/Date Received 2020-11-12

Claims (17)

I CLAIM:

1. A rotationally operable impact apparatus comprising:
a main body member;
a drive member operatively mounted on said 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 said main body member for rotation about an output axis;
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 said drive member and said output member for co-operative rotational and sliding movement with respect to said drive member and said output member between an anvil contact position whereat said anvil-impacting surface of said hammer lobe forcefully contacts said hammer-receiving surface of said anvil lobe and a released position whereat said hammer lobe moves longitudinally off and rotationally past said hammer-receiving surface of said anvil lobe;
spring means operatively interconnected between said drive member and said hammer member for biasing said hammer member to said anvil contact position;
wherein said spring comprises variable pitch spring having at least one smaller pitch coil and at least one larger pitch coil; and, Date Recue/Date Received 2020-11-12 guide means for guiding said hammer member between said anvil contact position and said released position when said drive member is rotated with respect to said output member by said spring means;
wherein, in use, rotation of said drive member about said drive axis causes potential energy to be stored in said spring means, whereat said hammer member is forced by said spring means longitudinally over and rotationally past said anvil lobe through its released position, to then be forcefully propelled by said spring means and the rotation of said drive member to impact on said hammer-receiving surface of said anvil portion, whereat force is transmitted from said hammer member to said anvil portion so as to create a moment about said output axis, thus urging said output member to forcefully rotate about said output axis.

2. The rotationally operable impact mechanism of claim 1, wherein the ratio of the smallest pitch in said at least one smaller pitch coil to the largest pitch in said at least one larger pitch coil is at least 1:2.

3. The rotationally operable impact mechanism of claim 1, wherein the at least one smaller pitch coil comprises a first smaller pitch coil section and a second smaller pitch coil section, and the at least one larger pitch coil comprises a first larger pitch coil section, and wherein the first larger pitch coil section is disposed between the first smaller pitch coil section and the second smaller pitch coil section.

4. The rotationally operable impact mechanism of claim 1, wherein the diameter of the wire forming the spring is between about 0.125 inches and about 0.162 inches.

5. The rotationally operable impact mechanism of claim 1, wherein the length of the spring is between about 1.0 inches and 3.0 inches.

Date Recue/Date Received 2020-11-12

6. The rotationally operable impact mechanism of claim 1, wherein the diameter of the spring is between about 1.0 inches and 1.5 inches.

7. The rotationally operable impact mechanism of claim 1, wherein the variable pitch spring comprises a progressive pitch spring.

8. The rotationally operable impact mechanism of claim 7, wherein the ratio of the smallest pitch in said at least one smaller pitch coil to the largest pitch in said at least one larger pitch coil is at least 1:2.

9. The rotationally operable impact mechanism of claim 7, wherein the at least one smaller pitch coil comprises a first smaller pitch coil section and a second smaller pitch coil section, and the at least one larger pitch coil comprises a first larger pitch coil section, and wherein the first larger pitch coil section is disposed between the first smaller pitch coil section and the second smaller pitch coil section.

10. The rotationally operable impact mechanism of claim 7, wherein the diameter of the wire forming the spring is between about 0.125 inches and about 0.162 inches.

11. The rotationally operable impact mechanism of claim 7, wherein the length of the spring is between about 1.0 inches and 3.0 inches.

12. The rotationally operable impact mechanism of claim 7, wherein the diameter of the spring is between about 1.0 inches and 1.5 inches.

13. The rotationally operable impact mechanism of claim 1, wherein said main body member comprises a housing.

Date Recue/Date Received 2020-11-12

14.
The rotationally operable impact mechanism of claim 1, wherein said output member extends between an impact receiving end and an output end, and has a tool-receiving portion at said output end.

15. A rotationally operable impact mechanism comprising:
a drive member 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 interconnected with respect to said drive member for rotation about an output axis;
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 said drive member and said output member for co-operative rotational and sliding movement with respect to said drive member and said output member between an anvil contact position whereat said anvil-impacting surface of said hammer lobe forcefully contacts said hammer-receiving surface of said anvil lobe and a released position whereat said hammer lobe moves longitudinally off and rotationally past said hammer-receiving surface of said anvil lobe;
spring means operatively interconnected between said drive member and said hammer member for biasing said hammer member to said anvil contact position;
wherein said spring comprises variable pitch spring having at least one smaller pitch coil and at least one larger pitch coil; and, Date Recue/Date Received 2020-11-12 guide means for guiding said hammer member between said anvil contact position and said released position when said drive member is rotated with respect to said output member by said spring means;
wherein, in use, rotation of said drive member about said drive axis causes potential energy to be stored in said spring means, whereat said hammer member is forced by said spring means longitudinally over and rotationally past said anvil lobe through its released position, to then be forcefully propelled by said spring means and the rotation of said drive member to impact on said hammer-receiving surface of said anvil portion, whereat force is transmitted from said hammer member to said anvil portion so as to create a moment about said output axis, thus urging said output member to forcefully rotate about said output axis.

16. A 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.

17. A rotationally operable impact mechanism comprising:

Date Recue/Date Received 2020-11-12 a drive member;
an output member;
a hammer member;
spring means comprising a variable pitch spring; and, guide means.

Date Recue/Date Received 2020-11-12