Patent Grant
7669290
The present invention relates to an anti-vibratory handle for tools producing vibrations, in particular but not exclusively percussive and other reciprocating tools. In operation, this anti-vibratory handle reduces transmission of vibrations from the tool to the hand(s) and upper limb(s) of the operator.
Various studies have been conducted on the effectiveness of anti-vibratory gloves:
All of these studies have demonstrated the effectiveness of such gloves for frequencies above the 100-140 Hz range, depending on the individual wearer. Below this range, however, anti-vibratory gloves are at best ineffective or tend to enhance vibrations transmitted to the hands (at resonance frequencies ranging from 30 to 45 Hz, depending on the type of glove and on the morphology of the palm of the worker).
In the particular context of percussion drills, with a dominant frequency corresponding to the frequency of impact (about 40 Hz), this type of glove may increase the exposure of workers to vibrations.
It should be noted nevertheless, that wearing gloves prevents direct contact of the hands with cold surfaces. This is a very positive factor that may limit the appearance of symptoms related to Raynaud's syndrome. The Raynaud's syndrome is well known to those of ordinary skill in the art and, therefore, will not be further described in the present specification.
Modification of the Handle
Numerous investigations have been conducted for the purpose of damping or insulating vibrations at the level of the handle or between the body of the percussion drill and the handle.
Among the most significant works, a Russian study in 1964 may be cited, which deals with the development of anti-vibratory handles [Paran'ko, N. M.; “Hygienic evaluation of vibration and noise damping devices for hand-operated pneumatic rock drills”; Pat. Fiziol., 4, 32-38; 1964]. Prototypes of handles developed in the context of this study showed effectiveness approaching a 50% reduction of vibrations, but in association with either too great an increase in weight or poor mechanical resistance.
A patent was granted to Shotwell in 1976 for an anti-vibratory handle for a portable pneumatic hammer [Shotwell D. B.; “Pneumatic percussion tool having a vibration dampened handle”. Caterpillar Tractor Co.; U.S. Pat. No. 3,968,843 issued on Jul. 13, 1976]. The invention described in U.S. Pat. No. 3,968,843 consists of a rubber element inserted between the handle and the body of the pneumatic hammer. According to this patent, an attenuation of vibrations at the frequencies of interest of the order of 17 dB may be obtained. However, no statement is made about the durability or ease of handling of the tool.
Aside from the above studies, those of Boileau [Boileau P. É.; “Les vibrations engendrées par les foreuses à béquille à la division Opémiska de Minnova”; Rapport IRSST B-027, Décembre 1990] tested and compared two anti-vibratory handles. One of these handles was, among other things, homemade and equipped with a resilient member placed between the handle and the body of a percussion drill. And this handle provided an attenuation of the order of 20% of the vibrations transmitted to the worker.
More recently, a study conducted in 1998 by the firm Boart Longyear Inc. led to the development of a new handle [Prajapati K., Hes P.; “Reduction of hand-arm transmitted Vibration on Pneumatic Jackleg Rock Drills”, Congrès CIM, Sudbury]. Tests showed an approximately 50% attenuation of non-weighted vibration levels. This attenuation is due primarily to a decrease of high frequency (>640 Hz) vibrations. The presented spectra fail to show any attenuation at the frequency of impact defined by Boileau [Boileau P. É.; “Les vibrations engendrées par les foreuses à béquille à la division Opémiska de Minnova”; Rapport IRSST B-027, Décembre 1990], among others, as the principal component of the weighted spectrum. The impact of the use of such a handle on the exposure of workers to vibrations thus remains minimal.
Prior Works Applied to Other Tools
Numerous studies have been conducted with the aim of reducing vibrations transmitted from chainsaws to the hands of the operators. The concept most generally used is uncoupling the chain guard and the saw handle from the moving mechanical parts (internal combustion engine and chain drive system) [Bierstecker, M.; “Vibration mount on a chainsaw”; U.S. Pat. No. 4,670,985 issued Jun. 9, 1987] [Gassen J. R.; Suchdev L. S.; “Vibration Reducing Chainsaw Handle”, U.S. Pat. No. 5,016,355 issued May 21, 1991]. Recent machines equipped with this type of suspension have greatly reduced the exposure of forestry workers to vibrations.
Various other studies have been conducted on concrete breakers. Although the source of vibrations in concrete breakers is very similar to that observed in air-leg percussion drills, the modes of operation of the two tools are quite different. The operator must hold continuously the concrete breaker using both hands and the direction of the work is generally vertical. Also, gripping of the concrete breaker differs greatly from gripping of the air-leg percussion drill, which is used essentially for making horizontal holes. In air-leg percussion drills, the drive force is produced essentially by the air-leg and the miner intervenes mainly to make the pilot hole necessary to keep the machine on the desired axis. The solutions developed within the context of these studies are therefore not directly applicable to percussion drills. One type of solution that may be cited is the development of flexible hoop-type handles or the installation of dynamic absorbers [IRGO-Pic™, Ingersoll-Rand™].
The present invention relates to an anti-vibratory handle for installation on a reciprocating tool supplied with a pressurized fluid and producing vibrations in the direction of an axis of reciprocation of the tool, comprising:
a stationary portion mounted to a body of the tool;
a mobile portion comprising a hand-grip member; and
an articulation between the stationary and mobile portions, the articulation comprising:
at least one conduit for supplying pressurized fluid to the reciprocating tool, the at least one conduit extending through the mobile portion, the articulation and the stationary portion.
The foregoing and other objects, advantages and features of the present invention will become more apparent upon reading of the following non-restrictive description of illustrative embodiments thereof, given by way of example only with reference to the accompanying drawings.
In the appended drawings:
a is a side perspective view of a resilient member for use in the first illustrative embodiment of anti-vibratory handle of
b is an underside elevational view of the resilient member of
a is a schematic diagram illustrating the direction of movement of the anti-vibratory handle of
b is a schematic diagram showing an angle for an arm member of a mobile portion of the anti-vibratory handle according to the first illustrative embodiment of the present invention, optimized for the JOY™ percussion drill;
a is a cross sectional, side elevational view of the anti-vibratory handle according to the first non-restrictive illustrative embodiment of the present invention, optimized for the JOY™ percussion drill;
b is a cross sectional, top plan view of the anti-vibratory handle according to first the non-restrictive illustrative embodiment of the present invention, optimized for the JOY™ percussion drill;
The development of an anti-vibratory handle for tools producing vibrations, such as percussive and other reciprocating tools, may be expressed in terms of three challenges:
More specifically,
Although the non-restrictive illustrative embodiments of the present invention will be described in relation to a percussion drill, is should be kept in mind that the present invention can be applied to other types of tools producing vibrations, in particular but not exclusively percussive and other reciprocating tools.
In accordance with the first non-restrictive illustrative embodiment, the anti-vibratory handle 14 comprises at least one arm member 15 having a proximal end connected to the body 11. The anti-vibratory handle 14 also comprises a hand-grip member 16 connected to the distal end of the arm member 15 through at least one arm member 17 and an articulation 18 comprising a pivot (not shown).
Still referring to
The double arrows 19 and 20 illustrate the vibrations of the body 11 of the drill 12 along the axis of percussion. As can be seen in
Under the influence of the back-and-forth movement (see double arrow 19 and 20 of
Although the attenuation of the vibrations along the axis of percussion (see double arrows 19 and 20) will produce a slight increase in vibratory movement along the longitudinal axis of the arm member 17 (see double arrow 23), the rotary concept of the anti-vibratory handle 14 affords major advantages in terms of design simplicity. In fact, it is relatively easy to obtain pure rotation. This type of movement can be achieved by means of a simple pivot supported by self-lubricating bearings. There are numerous low-cost, commercially available products for producing pure rotation.
Vibratory insulation is obtained by means of resilient members (not shown in
For pneumatic percussion drills, the angular movement of the hand-grip member 16 about the articulation 18 (see double arrows 21 and 22) will remain small; for example, an angular movement of ±5° (see double arrows 21 and 22) can be used for an axial displacement (see double arrow 20) of the anti-vibratory handle 14 handle of about 2 cm. With such a small angular movement, pneumatic connections under the form of flexible plastic tubes could be used without onset of material fatigue, even after a large number of bending cycles. In this manner, no complex air-tight connections are required and the structure of the articulation is thus greatly simplified to substantially reduce the costs.
The anti-vibratory handle 24 includes a stationary portion 25 integrated to the percussion drill (not shown) via a fixation cone 26 of the same type as those used for mounting conventional handles. Fixedly connected perpendicular to the fixation cone 26 is an arm member 27 extending in the direction of the axis of percussion. The arm member 27 comprises a pairs of opposite, longitudinal top and bottom flat faces 50 and 51. The distal end 28 of the arm member 27 forms part of the articulation 18 (
The anti-vibratory handle 24 also includes a mobile portion 29 comprising an arm member 30. The distal end of the arm member 30 is formed with a conical attachment device 31 of the type providing for direct attachment of a conventional hand-grip member (not shown) including controls for the operation of the percussion drill. This conventional hand-grip member may be identical in all respects to the existing JOY™ handle. The proximal end 32 of the arm member 30 also forms part of the articulation 18 (
The distal end 28 of the arm member 27 is formed with two parallel side ears 33 and 34 with respective coaxial threaded holes 35 and 36. The distal end 28 further comprises, between the ears 33 and 34, a flat face 37 perpendicular to the longitudinal axis of the arm member 27. A series of three axial holes such as 38 are provided through the flat face 37 between the two ears 33 and 34. These axial holes 38 are in communication with pressurized air transmitting conduits formed through the arm member 27.
The proximal end 32 of the arm member 30 has the general configuration of a hollow rectangular box-like structure with a face open toward the distal end 28 of the arm member 27. The rectangular box-like structure comprises:
Again, these holes 52 are in communication with pressurized air transmitting conduits formed through the arm member 30.
The articulation 18 between the arm members 27 and 30 finally comprises three flexible tubes such as 45 of equal length and two generally flat resilient members 46 and 47 L-shaped in cross section to define respective shoulders 48 and 49. For example, the tubes 45 can be made of plastic material and the resilient members 46 and 47 made of elastomeric material.
During installation, the following operations are performed:
In operation, the three tubes 45 will ensure transmission of pressurized air between the percussion drill and the control on the hand-grip member to enable control of the operation of the percussion drill by the worker. Sealing between the tubes 45 and the holes 38 and 52 is ensured by inflation of the tubes 45 when the air-leg of the percussion drill is supplied with pressurized air. As indicated in the foregoing description, with the small angular movement of, for example, ±5° between the arm members 27 and 30, the flexible plastic tubes 45 will bend without onset of material fatigue, even after a large number of bending cycles.
Also in operation, the resilient member 46 is compressed between the top flat face 50 of the arm member 27 and the inner face of the top wall 43, while the resilient member 47 is compressed between the bottom flat face 51 of the arm member 27 and the inner face of the top bottom wall 44. During small angular movements of the arm member 30 about the arm member 27, the stiffness of the resilient, for example elastomeric members 46 and 47 is linear. If the amplitude of the angular movements increases, the greater compression of the members 46 and 47 considerably increases their stiffness. Thanks to their non-linear behaviour, the resilient members 46 and 47 thus act both as vibration-damping insulators and flexible cushions intended to limit the angular movements of the arm member 30 about the arm member 27 for example to the above mentioned angular value of ±5°.
The shoulders 48 and 49 of the resilient members 46 and 47, located between the end flat face 37 and the internal end wall 53, retain the resilient members 46 and 47 in position between the top flat face 50 of the arm member 27 and the inner face of the top wall 43 and between the bottom flat face 51 of the arm member 27 and the inner face of the bottom wall 44, respectively.
The anti-vibratory handle 24 of
a and 5b illustrates a resilient member 60 for use as resilient members 46 and 47 of
It should be mentioned here that resilient members of other forms or nature can be used. For example, a torsion member can be used. This torsion member will be made of resilient material and interposed between the arm members 27 and 30. It is believed to be within the knowledge of those of ordinary skill in the art to design a torsional resilient member or other type of resilient member having the same function as the resilient members 46, 47 and 60.
Analysis of high-speed filming showed that the movement of the handle attachment point is not parallel to the axis of percussion of the JOY™ drill but 40° apart from this axis of percussion as shown in
a illustrates the situation for the case of the anti-vibratory handle 24 of
a and 8b are cross sectional, side elevational and top plan views of the anti-vibratory handle 24 optimized for the JOY™ percussion drill, while
The differences between the anti-vibratory handle of
The resulting anti-vibratory handle 24 of
The main difference between the original handles of SECAN™ and JOY™ percussion drills is the presence of a push-button valve on the hand-grip member.
As it was the case for the JOY™ percussion drill, the angle of movement of the hand-grip member was examined using a high-speed camera in order to optimize the design by maximizing the absorption of vibrations perpendicular to the axis of percussion. In the case of the SECAN™ percussion drill, the angle of movement is smaller than for JOY™ percussion drills, having a value of about 15°.
The anti-vibratory handle of
Turning now to
Generally stated, the principle of operation of the anti-vibratory handle 100 is similar to the principle of operation of the anti-vibratory handle 24 described in the foregoing description.
Referring now to
As non limitative example, the fixation cone 106 or, alternatively, the adaptor flange of the modified back part of the percussion drill 102 can be designed to fit on the above mentioned JOY™ and SECAN™ percussion drills.
The stationary portion 102 comprises an arm member 110 interconnecting the proximal end (fixation cone 106) to the distal end 108. The arm member 110 includes a first set of three conduits (not shown) to connect the pressurized air controls located on the mobile portion 104 of the handle 100 with the percussion drill, to thereby supply the tool with pressured air.
The proximal end 108 defines a shaft-receiving barrel 112 and a small hole 114 on the periphery of the barrel 112 at one open end thereof. At the same open end of the shaft-receiving barrel 112 is defined an annular shoulder 113. The end of the shaft-receiving barrel 112 opposite to the annular shoulder 113 defines a semicircular extension 115.
The mobile portion 104 includes an arm member 116. The arm member 116 comprises a distal end 118 defining an attachment device 120 of the type providing for direct attachment of a conventional hand-grip member 121 (
The shaft 124 includes a distal end 132 having a reduced diameter and comprising a transversal hole 134. When the anti-vibratory handle 100 is assembled, the distal end 132 is inserted in an aperture of reduced diameter (not shown) at the end of the barrel 112 opposite the shoulder 113.
A lock assembly 142 includes a block 144 and a locking pin 146 and is mounted on the distal end 132 on the end of the barrel 112 opposite to the shoulder 113. The block 144 comprises a first opening 147 destined to accommodate the distal end 132 of the shaft 124, a second opening 148 destined to accommodate the locking pin 146, and two hollows 150a and 150b destined to receive respectively two pins 152a and 152b, each of which has the function of a stopper abutting against respective sides 115a and 115b of the semicircular extension 115.
A torsion spring 136 comprising a longer end portion 138, an intermediate ring-shaped portion 137 and a shorter end portion 140 is interposed between the stationary portion 102 and the mobile portion 104 of the anti-vibratory handle 100. When the anti-vibratory handle 100 is assembled:
To assemble the anti-vibratory handle 100, the following operations are performed:
When the anti-vibratory handle 100 undergoes vibrations under the effect of the tool producing vibrations, the mobile portion 104 pivots about the longitudinal axis of the shaft-receiving barrel 112. The torsion spring 136 then acts as a resilient member, the spring constant of the torsion spring 136 creating a restoring force that drives the mobile portion 104 back to its rest position relative to the stationary portion 102. The two pins 152, in cooperation with the sides 115a and 115b of the semicircular extension 115, restrict the amplitude of the angular movement of the mobile portion 104 from its rest position by abutting against the respective sides 115a and 115b of the semicircular extension 115.
The above described second illustrative embodiment of anti-vibratory handle 100 using a torsion spring and O-rings has been developed for SECAN™ percussion drill but can be adapted to JOY™ drills by modifying the adaptor flange of the stationary portion 102. The following results have been obtained with prototypes using the embodiment of
Although the present invention has been described hereinabove by way of non-restrictive illustrative embodiments thereof, these embodiments can be modified at will, within the scope of the appended claims, without departing from the nature and spirit of the subject invention. For example, it should be understood that the anti-vibratory handle according to the non-restrictive illustrative embodiments of the present invention can be optimized for every type of percussion drill or other tool producing vibrations.
| Number | Date | Country | Kind |
|---|---|---|---|
| 2423282 | Mar 2003 | CA | national |
This application claims the benefit of and is a Continuation-In-Part of U.S. patent application Ser. No. 10/804,344 filed on Mar. 19, 2004 now abandoned which claims priority to CA Patent Application Serial No. 2,423,282 filed on Mar. 19, 2003; specifications of both applications are expressly incorporated herein, in their entirety, by reference
| Number | Name | Date | Kind |
|---|---|---|---|
| 1945430 | Garrett | Jan 1934 | A |
| 2058583 | Forss | Oct 1936 | A |
| 2182565 | Lofgren | Dec 1939 | A |
| 2353450 | Fischer | Jul 1944 | A |
| 2365536 | Fischer et al. | Dec 1944 | A |
| 2478784 | Serio | Aug 1949 | A |
| 2629364 | Anderson | Feb 1953 | A |
| 2718406 | Sawyer et al. | Sep 1955 | A |
| 2985078 | Leavell | May 1961 | A |
| 3028840 | Leavell | Apr 1962 | A |
| 3248974 | Alexander et al. | May 1966 | A |
| 3326304 | Johnson | Jun 1967 | A |
| 3571874 | Von Arz | Mar 1971 | A |
| 3923126 | Bidanset | Dec 1975 | A |
| 3968843 | Shotwell | Jul 1976 | A |
| 4036085 | Sjostrand et al. | Jul 1977 | A |
| 4248441 | Joseph | Feb 1981 | A |
| 4368556 | Wanner et al. | Jan 1983 | A |
| 4478293 | Weilenmann et al. | Oct 1984 | A |
| 4522270 | Kishi | Jun 1985 | A |
| 4592109 | Borea et al. | Jun 1986 | A |
| 4609055 | Grafstrom et al. | Sep 1986 | A |
| 4648468 | Honsa | Mar 1987 | A |
| 4667749 | Keller | May 1987 | A |
| 4670985 | Biersteker | Jun 1987 | A |
| 4771833 | Honsa | Sep 1988 | A |
| 4883211 | Philipp et al. | Nov 1989 | A |
| 4912349 | Chang | Mar 1990 | A |
| 5016355 | Gassen et al. | May 1991 | A |
| 5025870 | Gantner | Jun 1991 | A |
| 5054562 | Honsa et al. | Oct 1991 | A |
| 5065476 | Dohse et al. | Nov 1991 | A |
| 5273120 | Chang | Dec 1993 | A |
| 5405216 | Allen et al. | Apr 1995 | A |
| 5442992 | Sanner et al. | Aug 1995 | A |
| 5533579 | Chu | Jul 1996 | A |
| 5626199 | Henry et al. | May 1997 | A |
| 5653370 | Bereiter et al. | Aug 1997 | A |
| 5727829 | Bellichak | Mar 1998 | A |
| 5839517 | Gwinn et al. | Nov 1998 | A |
| 5845364 | Chen | Dec 1998 | A |
| 5898980 | Havranek et al. | May 1999 | A |
| 5911263 | Wu | Jun 1999 | A |
| 5927407 | Gwinn et al. | Jul 1999 | A |
| 6026910 | Masterson et al. | Feb 2000 | A |
| 6076616 | Kramp et al. | Jun 2000 | A |
| 6145899 | Kelemen | Nov 2000 | A |
| 6155354 | Pusateri et al. | Dec 2000 | A |
| 6189420 | Shiao | Feb 2001 | B1 |
| 6216317 | Chen | Apr 2001 | B1 |
| 6317930 | Hung | Nov 2001 | B1 |
| 6339979 | Chiang | Jan 2002 | B1 |
| 6386075 | Shiao | May 2002 | B1 |
| 6397436 | Wang | Jun 2002 | B1 |
| 6421880 | Prajapati et al. | Jul 2002 | B1 |
| 6467130 | Kurachi et al. | Oct 2002 | B2 |
| 6557212 | Huang | May 2003 | B2 |
| 6837415 | Huang | Jan 2005 | B1 |
| 20010034940 | Marshall et al. | Nov 2001 | A1 |
| 20020020042 | Kurachi et al. | Feb 2002 | A1 |
| 20050050690 | Oddo et al. | Mar 2005 | A1 |
| Number | Date | Country | |
|---|---|---|---|
| 20070107165 A1 | May 2007 | US |
| Number | Date | Country | |
|---|---|---|---|
| Parent | 10804344 | Mar 2004 | US |
| Child | 11543700 | US |
