EP0680399A4 - Isolateur de vibrations pour dispositifs vibrants tenus en main. - Google Patents

Isolateur de vibrations pour dispositifs vibrants tenus en main.

Info

Publication number
EP0680399A4
EP0680399A4 EP94905414A EP94905414A EP0680399A4 EP 0680399 A4 EP0680399 A4 EP 0680399A4 EP 94905414 A EP94905414 A EP 94905414A EP 94905414 A EP94905414 A EP 94905414A EP 0680399 A4 EP0680399 A4 EP 0680399A4
Authority
EP
European Patent Office
Prior art keywords
isolator
buckling
elastomer
hand
tool body
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Granted
Application number
EP94905414A
Other languages
German (de)
English (en)
Other versions
EP0680399A1 (fr
EP0680399B1 (fr
Inventor
James T Gwinn
Robert H Marjoram
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Lord Corp
Original Assignee
Lord Corp
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Lord Corp filed Critical Lord Corp
Publication of EP0680399A1 publication Critical patent/EP0680399A1/fr
Publication of EP0680399A4 publication Critical patent/EP0680399A4/fr
Application granted granted Critical
Publication of EP0680399B1 publication Critical patent/EP0680399B1/fr
Anticipated expiration legal-status Critical
Expired - Lifetime legal-status Critical Current

Links

Classifications

    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B25—HAND TOOLS; PORTABLE POWER-DRIVEN TOOLS; MANIPULATORS
    • B25D—PERCUSSIVE TOOLS
    • B25D17/00—Details of, or accessories for, portable power-driven percussive tools
    • B25D17/04—Handles; Handle mountings
    • B25D17/043—Handles resiliently mounted relative to the hammer housing
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B25—HAND TOOLS; PORTABLE POWER-DRIVEN TOOLS; MANIPULATORS
    • B25D—PERCUSSIVE TOOLS
    • B25D17/00—Details of, or accessories for, portable power-driven percussive tools
    • B25D17/04—Handles; Handle mountings
    • B25D17/046—Sleeve-like handles surrounding the tool bit
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B25—HAND TOOLS; PORTABLE POWER-DRIVEN TOOLS; MANIPULATORS
    • B25D—PERCUSSIVE TOOLS
    • B25D17/00—Details of, or accessories for, portable power-driven percussive tools
    • B25D17/24—Damping the reaction force
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B25—HAND TOOLS; PORTABLE POWER-DRIVEN TOOLS; MANIPULATORS
    • B25D—PERCUSSIVE TOOLS
    • B25D2222/00—Materials of the tool or the workpiece
    • B25D2222/54—Plastics
    • B25D2222/57—Elastomers, e.g. rubber
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B25—HAND TOOLS; PORTABLE POWER-DRIVEN TOOLS; MANIPULATORS
    • B25D—PERCUSSIVE TOOLS
    • B25D2250/00—General details of portable percussive tools; Components used in portable percussive tools
    • B25D2250/371—Use of springs
    • B25D2250/381—Leaf springs

Definitions

  • This invention relates to the area of vibration isolators. Specifically, the invention relates to the area of elastomer-containing vibration isolators for isolation of a user from mechanical vibrations of hand-held vibrating devices.
  • Shotwell which is hereby incorporated by reference, and provides a pneumatic air hammer with a shock and vibration-absorbing insert or cushion member 30 between the body of the tool 10 and the handle 19.
  • the isolator used is a plain compression-type sandwich isolator. Its theory of operation is to place a soft spring between the user and the vibrating device, thus isolating the user from mechanical vibration.
  • compression- type isolators have one serious drawback. They experience an inherent stiffening effect when the operator exerts an increased force on the tool. This is due to the inherent strain sensitivity of elastomer in compression. Because of this, as the force increases, the level of vibration felt by the user is worsened. In other words, the harder the operator pushes the more ineffective the isolator becomes.
  • US Patent 2,500,036 to Horvath uses dual resilient members 80 and 81 to allow limited axial movement and restrain cocking. It also uses a plurality of locking segments 85 to restrain torsional rotation of the handle member 13 relative to the barrel 10.
  • the present invention has been designed to provide an improved vibration isolator for reducing the mechanical vibration level transmitted to the user in order to overcome the features and shortcomings of the available mountings for vibrating hand-held devices and tools.
  • the present invention is designed to provide an isolator for use in a vibrating hand-held device with a spring rate characteristic which softens as the operator increases the force applied to the device thereby improving the vibration isolation and solving the stiffening effect inherent in the isolators used in prior art hand-held vibrating devices.
  • the present invention provides an isolator for use in a hand-held vibrating device which exhibits a spring rate characteristic for the mounting which softens by about a factor of 2 or more with increased application of force by the operator thus improving the vibration isolation.
  • the present invention provides an isolator for use in a hand-held vibrating device which exhibits a spring rate characteristic for the mounting which softens by about a factor in the range of 2 to 20 with increased application of force by the operator thus improving the vibration isolation.
  • the present invention also provides an elastomeric isolator for a hand-held vibrating device which uses a buckling section incorporated into the isolator within the hand-held vibrating device.
  • the present invention also provides a buckling section isolator for incorporation into the vibrating device which is a means for allowing axial vibration isolation of the tool body relative to the tool handle with means incorporated for restraining torsional rotational and cocking of the tool body relative to the tool handle essential for control of the vibrating device.
  • the present invention also provides a buckling elastomer isolator for incorporation into the vibrating device which includes a means for snubbing to prevent unwanted excess motions.
  • the present invention includes an elastomeric grip isolator for use on a vibrating device which is a means for providing radial vibration isolation to the user by incorporating multiple radial buckling elements into the grip isolator.
  • the present invention further includes an elastomeric and fluid isolator for use on a vibrating hand-held device which is a means for providing vibration isolation of the user at a discreet operating frequency by incorporating inertial fluid forces within the elastomeric and fluid isolator.
  • the present invention further includes an elastomeric and tuned mass isolator for use on a vibrating hand-held device which is a means for providing vibration isolation of the user at a discreet operating frequency by incorporating inertial forces within the vibrating device.
  • the present invention further includes a buckling isolator for use on a vibrating hand-held device wherein said buckling isolator includes metal buckling elements for providing vibration isolation of the user.
  • the present invention includes an elastomeric and fluid isolator for use on a vibrating hand-held device which is a means for providing vibration isolation of the user at a discreet operating frequency by incorporating inertial fluid forces within the elastomeric and fluid isolator and which utilizes a buckling section within the isolator.
  • a vibration isolator for use on a hand ⁇ held vibrating device for reducing the mechanical vibration imparted to the user, comprising a handle for being grasped by said user; a tool body; and a vibration isolator attached between the handle and the tool body, said vibration isolator including a buckling section which buckles under application of load, thus reducing the spring rate within an operating range and reducing said mechanical vibration imparted to said user within said operating range.
  • an elastomeric vibration isolator for use on a hand-held vibrating device which reduces the radial mechanical vibration imparted to the user, comprising a body of elastomer for being grasped by said users hand, said body of elastomer disposed about a central axis; multiple buckling sections extending radially inward toward said central axis, said buckling sections buckling under application of load and reducing the spring rate which improves radial vibration isolation.
  • the lower stiffness as compared to conventional isolators at the optimum operating load, reduces the vibrating forces transmitted to the user. It is an advantage of the present invention that the buckling element incorporated into the isolators can reduce the vibration experienced by the user.
  • the axial isolation can be dramatically increased without reducing the control of the vibrating device by restraining both cocking motion and torsional motion of the tool handle relative to the tool body .
  • the axial isolation can be dramatically increased by tuning an amplified fluid inertial force to coincide with the operating frequency.
  • Fig. 1A is a partially sectioned side view showing the installation of a embodiment of the buckling isolator and an embodiment of the grip isolator o a hand-held vibrating device;
  • Fig. IB is a partially sectioned side view showing a second embodiment of the grip isolator
  • Fig. 2A is a sectioned side view illustrating an embodiment of a grip isolator for a hand-held vibrating device as seen along line 2A-2A in Fig. 2B;
  • Fig. 2B is an end view illustrating an embodiment of the grip isolator and illustrating the multiple buckling sections
  • Fig. 2C is an enlarged partial isometric view illustrating one of the buckling sections of the grip isolator
  • Fig. 2D is an end view illustrating another embodiment of the grip isolator and shows the multiple buckling sections
  • Fig. 2E is a sectioned side view illustrating an embodiment of a grip isolator for a vibrating device as seen along lines 2E-2E in Fig. 2D;
  • Fig. 2F is an enlarged end view with a portion broken away illustrating the means for restraining torsional motion for the vibrating device
  • Fig. 2G is a partial end view illustrating one buckling section of the grip isolator in the buckled state
  • Fig. 2H is an enlarged partial end view illustrating the dimensions of the buckling section of the grip isolator
  • Fig. 3A is a top view of a first embodiment of the buckling isolator
  • Fig. 3B is a sectioned side view of the buckling isolator as seen along line 3B-3B in Fig. 3A;
  • Fig. 3C is a side view of the first embodiment of the buckling isolator shown in the buckled state
  • Fig. 3D is a partially sectioned side view of another embodiment of the buckling isolator for use in a hand-held vibrating device;
  • Fig. 3E is an enlarged partially sectioned side view of the second embodiment of the buckling isolator
  • Fig. 4A is a sectioned side view of an embodiment of a fluid and elastomer isolator installed within a hand-held vibrating device;
  • Fig. 4B is a sectioned side view of a second embodiment of a fluid and elastomer isolator
  • Fig. 5A is a graph illustrating the spring rate characteristics exhibited by the buckling isolator within the hand-held vibrating device
  • Fig. 5B is a graph illustrating the spring rate characteristics exhibited by the fluid and elastomeric isolator within the hand-held vibrating device
  • Fig. 6A is a sectioned side view of a third embodiment of an isolator for use in hand tools employing a tuned vibration absorber;
  • Fig. 6B is a sectioned side view of a fourth embodiment of an isolator for use in hand tools which uses a hybrid absorber/buckling column isolator;
  • Fig. 6C is a graph illustrating the intended performance characteristics of the third embodiment of isolator within the hand-held vibrating device
  • Fig. 6D is a graph illustrating the actual performance characteristics exhibited by the third embodiment of isolator within the hand- held vibrating device
  • Fig. 7A is a perspective view of a fifth embodiment of the isolator of the present invention depicting the use of metallic bucking springs;
  • Fig. 7A' is an enlarged cross-sectional side view of an individual spring element of the isolator of Fig. 7A with the buckled position shown in dotted line;
  • Fig. 7B is a perspective view of a sixth embodiment of the isolator of the present invention depicting a second form of metallic buckling spring;
  • Fig. 7B' is an enlarged cross-sectional side view of an individual spring element of the isolator of Fig. 7B with the buckled position shown in dotted line;
  • Fig 7C is a perspective view of a seventh embodiment of the isolator of the present invention depicting a third form of metallic buckling spring.
  • Fig 7C is an enlarged cross-sectional side view of an individual spring element of the isolator of Fig. 7C with the buckled position ghosted in.
  • a buckling isolator 20A and a separate embodiment of a grip isolator 30A are shown installed in the environment of the hand-held vibrating device 10.
  • the vibrating device 10 that is used to illustrate the present invention is a pneumatic air hammer, but the buckling isolator 20A and grip isolator 30A are equally effective, when properly situated, for any type of hand-held vibrating equipment or device.
  • the pneumatic air hammer or vibrating device 10 in the present invention includes a tool bit 32 (Fig. IB) which is preferably steel and which contacts the work piece (not shown).
  • the vibrating device 10 also includes a handle 34 which is grasped by a first rear hand of the user. Further, the handle attaches to a sleeve 36 that is preferably cylindrically shaped. However, a sleeve integrated into a handle may be envisioned, as well.
  • the buckling isolator 20A attaches to the handle 34 by way of bolts or other fastening means 37.
  • the other end of buckling isolator 20A is attached to the tool body 38 by bolts or other fastening means 37.
  • the buckling isolator 20 attaches between the tool body 38 and the handle 34 and allows the tool body 38 to deflect axially and thus acts as an isolator spring between the tool body 38 and handle 34.
  • the axial motion is limited by a snubber 48.
  • the snubber consists of a collar 47 which is part of or attached to the tool body 38 and a series of shoulders 49A and 49B which alternatively contact the ends of the collar 47 at the excursion limits.
  • the snubber 48 constrains the movement in the axial direction to 0.4 inch (in.) maximum compression deflection and 0.1 inch (in.) tensile deflection.
  • the tool body 38 is restrained from cocking relative to the sleeve 36 and, thus also, the handle 34 by way of sliding surfaces 40A and 40B which are axially spaced and which lightly contact the outer periphery 42 of the tool body 38.
  • the sliding surfaces 40A and 40B and/or outer peripheries 42 are coated with Teflon ® or other suitable means for reducing friction. This allows the tool body 38 to slide telescopically within the sleeve 36 and compress axially the elastomeric buckling section 44A of the buckling isolator 20A, thus reducing the spring rate in the axial direction within a working thrust load range to be described later.
  • splines or keys 50 which are added on the tool body 38 are received within grooves 52 formed in the sleeve 36. Together, the splines or keys 50 and grooves 52 comprise the means for restraining torsional movement 56, while allowing unrestricted axial motion. Other means of restraining torsional movement such as flats and non-round shapes are also acceptable.
  • the sliding surfaces 40A and 40B together with the outer periphery 42 of the tool body 38 act as the means for restraining cocking motion while allowing relatively unrestricted axial motion.
  • the cocking and torsional modes are restrained, but axial displacement of the tool body 38 relative to the handle 34 can occur by compressing the buckling isolator 20A.
  • the buckling isolator 20A achieves a much lower axial spring rate than prior art devices.
  • that force will compress the buckling isolator 20A and cause the elastomeric section 44A to undergo buckling.
  • the elastomeric section 44A will experience a high static stiffness initially, yet as more force is applied and the elastomeric section 44A starts to buckle, the force needed to maintain the section in buckling falls off dramatically.
  • the initial static spring rate of the buckling isolator is 375 lbf/in at 5 lbf load and at the operating load of 40 lbf the spring rate is 15 lbf/in.
  • the buckling isolator 20A provides axial vibration isolation superior to the prior art compression-type isolators and fluid damped mounts for vibrating hand-held devices. However, in some instances, radial vibration can impart severe vibration to the user, in spite of the isolator 20A as a result of the key 50 hammering in keyway 52.
  • a first embodiment of a grip isolator 30A is shown.
  • the grip isolator 30A functions both as a grip for the user to grasp the vibrating device 10 and also as a radial and axial isolator to isolate the user from radial and axial mechanical vibration emanating therefrom.
  • the grip isolator 30A can be installed on the vibrating device 10 at an point which is convenient, such as tool body 38 (Fig. 1A).
  • the grip isolator 30B could encircle the tool 32 (Fig. IB). In some instances, this latter embodiment will be preferred as many operators desire to grip the hammer 10 as far forward as possible for improved balance.
  • the grip isolator 30A includes a body of elastomer 46B, a multiple number of buckling sections 44B extending radially inward from the body of elastomer 46B toward a central axis A. As shown in Fig. 2C these buckling sections 44B have a length L (in.), a width W (in.), a thickness t (in.), and are molded of elastomer with a shear modulus G (psi). The parameters L, W, t, and G can be chosen to provide the optimum buckling for the vibrating device 10 (Fig. 1A).
  • the buckling sections are formed by substantially parallel slots 45 extending into said body of elastomer 46B. As fully set forth in the two Schwemmer patents and the patents to Henshaw and Gensheimer, in order to exhibit buckling, the sections must have a length to thickness ratio L/t > 2.
  • Prior art grips have included foam rubber construction which has excellent vibration isolation characteristics; however, these grips quickly deteriorate due to abrasion, are of poor overall strength, and are subject to being contaminated with oil.
  • Prior art natural rubber grips were more rugged than foam grips, but failed to properly isolate the user's hand.
  • the present invention grip isolator 30 is slid over the member to be isolated 32 or 38, such that in its static form, the buckling sections 44B are buckled and the user is optimally isolated from the vibration (See Fig. 2G).
  • the present invention provides a rugged grip that is capable of isolating the user from vibration.
  • a second embodiment of grip isolator 30B is illustrated in Fig. 2D and 2E.
  • This embodiment is comprised of a body of elastomer 46C, but the buckling sections 44C are formed by a series of substantially parallel cores or bores 58 extending into the body of elastomer 46C.
  • the large bore 60 as installed, has an interference fit with the member to be isolated, such as a tool bit 32 (Fig. IB) or tool body 38 (Fig. 1A).
  • An intermediate wall 59 (Fig. 2E) of elastomer provides radial stability to bores 58 while permitting axial softness of the isolator 30B.
  • the buckling sections 44 C have low combined axial stiffness to provide isolation from axial vibrations. This configuration is preferred for usage in the Fig. IB environment where the axial vibration will be pronounced.
  • the soft elastomer which is used preferably has a hardness in the range of 30 to 100 durometer. Ideally, soft natural rubber with a shear modulus of approximately 75 psi should be used for the grip isolator 30A and 30B.
  • Fig. 2H illustrates the buckling sections 44C having a length L, a width W, a thickness t, and which are molded of elastomer with a shear modulus G.
  • the parameters L, W, t, are chosen to make the buckling section 44 buckle properly for the application.
  • Other shapes of bored out or cored out sections can be envisioned which will allow buckling, such as rectangular, triangular, and sections which direct the buckling direction.
  • FIG. 3A and 3B A view of a first embodiment of buckling isolator 20A is illustrated in Fig. 3A and 3B.
  • the isolator 20A is comprised of a first end member 62, a second end member 64, and a body of elastomer 46A integrally bonded to the members 62 and 64.
  • the body of elastomer 46A includes a buckling section 44A which buckles outwardly under the application of load as shown in Fig. 3C.
  • Figs. 3D and 3E illustrate another type of buckling isolator 20B for use in a hand-held vibrating device 10.
  • This buckling isolator 20B has a slight taper from either end member 62 and 64 on the outside surface of the body of elastomer 46D such that the center most portion is thinnest. This is to promote inward directional buckling of the W-shaped buckling section 44D.
  • this second embodiment offers a more compact envelope.
  • a fluid-and-elastomer version of the buckling isolator 20C is shown.
  • the buckling isolator 20C includes a irst variable volume fluid chamber 68, a second variable volume fluid chamber 70 and a fluid passageway 72 which allows for fluid communication between the chambers 68 and 70.
  • Fluid 74 substantially fills, and is contained within, the chambers 68 and 70 and the fluid passageway 72.
  • the theory of operation of the fluid and elastomer isolator is simple. As the air pulses enter the device 10 through an air passage or air supply tube 80A and excite the tool body 38, the tool body 38 oscillates correspondingly.
  • the dynamic oscillation of the tool body 38 relative to the handle 34 will cause the buckling section 44E to flex dynamically. This will pump fluid 74 from one chamber 68 to the other 70. Because of the differential in area between the fluid passageway 72 and the fluid chambers 68 and 70, and the transmissibility at resonance of the fluid 74, the fluid 74 can be accelerated to very large velocities as it flows through the passageway 72 and can generate significant phased counter inertial forces. As a result, with proper tuning, these inertial forces can be tuned to provide a dynamic stiffness notch at a predominant operating frequency. This will substantially reduce the vibration transmitted to the user.
  • a first flexible element 76 which defines a portion of the first variable volume fluid chamber 68 is a fabric reinforced diaphragm.
  • the diaphragm accommodates temperature expansion and allows static displacement of fluid from one chamber to another.
  • a second flexible element 78 which defines a portion of the second variable volume fluid chamber 70 includes the buckling section 44E.
  • the air passage 80 is a flexible bellows such as a steel spring bellows and passes through the second variable volume fluid chamber 70.
  • Fig. 4B a second embodiment of a fluid and elastomer version of the buckling isolator 20C is shown.
  • the only difference between the embodiment shown in Fig. 4A and this one is in the construction of the air passage 80B.
  • the air passage 80B slides telescopically within a tube 82 attached to the tool body.
  • a pair of seals 84 prevents fluid 74 from escaping from the chamber 68 and air from entering the chamber 68.
  • a performance curve of the buckling isolators 20A, 20B, and 20C are shown.
  • the performance curve plots axial load in pounds force (lbf.) on the vertical axis versus deflection in inches (in.) on the horizontal axis and is split into five different sections labeled 1 to 5.
  • Section 1 of the curve illustrates the initial-low-strain spring rate, prior to the occurrence of any buckling.
  • Section 2 illustrates the onset of buckling where the spring rate begins to fall off.
  • Section 3 illustrates the optimum operating point where the tangent spring rate is the lowest.
  • Section 4 is where the buckling section is so buckled that it begins to behave as a compression element and substantially stiffens.
  • Section 5 is where the buckling section is bottomed out and begins to snub.
  • a performance curve of a fluid and elastomer version of the buckling isolator 20C is shown.
  • the curve section labeled 1 is the low frequency dynamic stiffness which is essentially the contribution due to the elastomer stiffness.
  • Section 2 is the notch section. The notch is tuned to coincide with the fundamental frequency of input vibration by varying the functional characteristics of the fluid portion, e.g., the length of the inertia track, density of the fluid, etc.
  • Section 3 is the peak dynamic stiffness and coincides closely with the fluid natural frequency.
  • Section 4 is the high frequency stiffness after the fluid dynamically locks up and no longer flows through the fluid passageway.
  • Fig. 6A is described another embodiment of isolator 20F.
  • This isolator 20F is useful for reducing the vibration transmitted to a user from a hand-held device and the like.
  • like numerals denote like elements as compared to the previous embodiments.
  • the device is comprised of a handle 34F, a sleeve 36F attached to said handle 34F, and a tool body 38F similar to the previous embodiments.
  • the main difference is that the reduction in spring rate within an operating range of frequency is accomplished by incorporating a first and second elastomer 84 and 85 and a suspended, tuned mass 86.
  • the first elastomer element 84 is a pure shear element, i.e., under axial loading along axis Y-Y, the first elastomer section 84 is placed in pure shear.
  • the second elastomer section 85 is preferably also a pure shear section, but either could be a compression loaded section as well.
  • the first elastomer section 84 is integrally and chemically bonded to the first end member 62F and the second end member 64F.
  • the first end member includes a sleeve portion 87 and an attached plate portion 89 which is secured to the handle 34F.
  • the second end member 64F is comprised of a sleeve portion 87' and an attached plate portion 89' which, in turn, attaches to the tool body 38F.
  • the first elastomer section 84 provides a flexible connection between, and acts to isolate, the handle 34F from the tool body 38F by allowing relative axial motion therebetween. Snubber 48 limits the axial motion in a similar manner as the previous embodiments.
  • the mass 86 is also integrally attached to and chemically bonded to the first end member 62F.
  • Mass 86 and second elastomer element 85 are tuned such that the mass 86 resonates at a frequency just above the frequency of interest, i.e., the motor frequency or air hammer frequency.
  • the operating range for example, will be between about 28 and 31 Hz.
  • the input vibration for a air hammer is about 30 Hz. This provides a reduction in the transmission of mechanical vibration to the user within the frequency range.
  • Fasteners 37F and 37F' secure the first end member 62F and second end members 64F to the handle 34F and tool body 38F respectively.
  • Fig. 6B is another embodiment of isolator 20G.
  • This embodiment is similar to the embodiment in Fig. 6A except the first elastomer element 84G is a buckling section.
  • Buckling sections are described in the art in US Pat. Nos. 3,948,501, 3,798,916, 3,280,970, and Re 27,318.
  • the element 84G buckles radially inward (as shown in dotted lines) upon application of axial load.
  • the mass 86 and second elastomer element 85 function as a tuned absorber as in the previous embodiment.
  • the buckling section is preferably integrally and chemically bonded between the cup-shaped first end member 62F' and plate-like second end member 64F'.
  • the tuned absorber is comprised of mass 86 and elastomer element 85, which can further reduce the vibration imparted to the user.
  • Fig. 6C is an illustration of the intended or analytical performance of the tuned absorber embodiment of isolator 20F of Fig. 6A.
  • the solid line 88 indicates the analytical performance of the system without a tuned absorber and including a shear type first elastomer element 84 (Fig. 6A).
  • the resonance at about 9 Hz is the system resonance.
  • the curve indicated at 90 is for a system including a very small mass for the tuned mass 86 (Fig. 6A).
  • the curve 92 illustrates a mass 86 (Fig. 6A) used it the experiment of about 1 (lb) pound in weight. Theoretically, for this example, a range of improved isolation can be seen between about 28-31 Hz where the peak accelerations are reduced.
  • Fig. 6D is an illustration of the actual experimental performance of the tuned absorber embodiment of isolator 20F of Fig. 6A.
  • the solid line 94 indicates the performance in peak acceleration in inches per second squared (in/s 2 ) as a function of frequency (Hz). As expected, the peak accelerations are substantially reduced within the operating range of about 28-31 Hz.
  • Fig. 7A is an illustration of another embodiment of buckling isolator 20H.
  • the isolator 20H buckles radially outward under application of load such that the spring rate is reduced within a deflection range in a similar manner as the aforementioned elastomer embodiments.
  • the isolator 20H is comprised of a series of buckling elements 95H extending between end portions 96H and 97H. End portions 96H and 97H attach to tool handle 34H and tool body 38H, respectively.
  • the buckling elements 95H have a curvature formed thereon for biasing the buckling in one direction.
  • the buckling elements 95H are preferably metal and are formed from a stamped and bent sheet and are preferably made of spring-type steel or are made into spring-type steel through an appropriate heat treatment operation. As shown in Fig. 7A ⁇ upon application of axial load, the buckling element 95H will buckle radially outward as shown in dotted lines.
  • Fig. 7B is an illustration of another embodiment of buckling isolator 20J.
  • This embodiment is functionally similar to the Fig. 7A embodiment except that the buckling elements 95 J are not part of a stamped plate.
  • the elements 95 J are individual and preferably metal members of wire shape with a curvature formed thereon. The preferable cross section is rounded.
  • the wire-type buckling elements 95J are fitted in recesses in end portions 96J and 97J.
  • the buckling members 95 J are made from spring steel or the like. Upon buckling, the axial spring rate is substantially reduced.
  • Fig. 7C is an yet another illustration of an embodiment of buckling isolator 20K.
  • the buckling elements 95K are strip members with coiled or wrapped ends for accepting pins 99K.
  • the members 95K preferably have a curvature along their length to initiate or bias buckling in the proper direction.
  • the members 95 are connected to clevises 98K or the like such that a pin joint is formed by pins 99K interacting with coiled ends at the interface with end portions 96K and 97K.
  • Fig. 7C' illustrates the buckling element 95K in its buckled form. Upon buckling, the axial spring rate is substantially reduced.
  • the present invention relates to a vibration isolator for use on a hand-held vibrating device for reducing the mechanical vibration imparted to the user.
  • One embodiment of isolator attaches between the tool body and the handle reduce the mechanical vibration within a range of frequency or deflection range.
  • Embodiments are drawn to buckling elastomer type and buckling metal type isolators, tuned fluid isolators, and tuned mass isolators for reducing the spring rate within a range.
  • the buckling means attaches between a handle for being grasped by said user and a tool body and the initial spring rate is reduced within an operating range upon application of load.
  • a tuned fluid is used to generate counter inertial fluid forces for reducing the transmitted forces within a frequency range, while in the tuned absorber embodiment, the tuned mass and second spring are tuned to provide the vibration reduction within a frequency range.
  • the grip isolator embodiment comprises multiple buckling means extending radially inward toward a central axis of said hand-held vibrating device for exhibiting an installed radial spring rate in a buckled condition which is lower than a spring rate in a non-installed condition. All of these isolators are intended to reduce the mechanical vibration imparted to the user and reduce or eliminate the incidence of "white hand" or other phsiological deterioration.

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  • Engineering & Computer Science (AREA)
  • Mechanical Engineering (AREA)
  • Vibration Prevention Devices (AREA)

Abstract

Isolateur utilisé dans un dispositif (10) vibrant tenu en main et destiné à fournir une isolation optimale contre les vibrations grâce à des sections (44A) élastomères de flambage qui fonctionnent selon un mode de flambage pendant l'utilisation normale. Lesdites sections (44A) élastomères de flambage réduisent considérablement la constante de rappel au sein d'une gamme de charges de fonctionnement, réduisant ainsi considérablement les vibrations transmises à l'utilisateur. On décrit six modes de réalisation qui comportent des sections de flambage destinées à améliorer l'isolation contre les vibrations le long d'une direction axiale de vibration. Un premier mode de réalisation comporte une section (20A) tronconique. Un premier mode de réalisation d'un isolateur (30A) de poignée avant qui est utilisé avec l'isolateur (20A) à flambage pour réduire les vibrations mécaniques radiales transmises à la paume de la main de l'utilisateur, également à l'aide de sections de flambage, est également décrit.
EP94905414A 1993-01-27 1993-12-16 Isolateur de vibrations pour dispositifs vibrants tenus en main Expired - Lifetime EP0680399B1 (fr)

Applications Claiming Priority (3)

Application Number Priority Date Filing Date Title
US969393A 1993-01-27 1993-01-27
US9693 1993-01-27
PCT/US1993/012271 WO1994016864A1 (fr) 1993-01-27 1993-12-16 Isolateur de vibrations pour dispositifs vibrants tenus en main

Publications (3)

Publication Number Publication Date
EP0680399A1 EP0680399A1 (fr) 1995-11-08
EP0680399A4 true EP0680399A4 (fr) 1996-01-10
EP0680399B1 EP0680399B1 (fr) 2000-11-15

Family

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Family Applications (1)

Application Number Title Priority Date Filing Date
EP94905414A Expired - Lifetime EP0680399B1 (fr) 1993-01-27 1993-12-16 Isolateur de vibrations pour dispositifs vibrants tenus en main

Country Status (3)

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EP (1) EP0680399B1 (fr)
DE (1) DE69329686T2 (fr)
WO (1) WO1994016864A1 (fr)

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KR19980702910A (ko) * 1996-01-11 1998-09-05 윌리엄 엠. 토마스 공압공구 및 이것을 위한 진공격리기의 장착부
US5813477A (en) * 1996-05-23 1998-09-29 Chicago Pneumatic Tool Company Vibration-reduced impact tool and vibration isolator therefor
US5769174A (en) * 1996-12-18 1998-06-23 Ingersoll-Rand Company Parallel displacement single axis vibration isolator
KR100260309B1 (ko) * 1997-06-11 2000-07-01 최해성 유압헤머
US6026910A (en) * 1998-01-13 2000-02-22 Chicago Pneumatic Tool Company Power tool and vibration isolator therefor
US6148734A (en) * 1998-05-19 2000-11-21 Lord Corporation Elastomeric bearing with softening spring rate
JP2002039267A (ja) * 2000-07-31 2002-02-06 Kioritz Corp 防振部材及び防振装置
US7676890B2 (en) 2005-10-25 2010-03-16 Black And Decker, Inc. Vibration dampening handle for a powered apparatus
EP1787761B1 (fr) * 2005-11-16 2010-01-06 Metabowerke GmbH Perçeuse motorisée à percussion
DE102006034078A1 (de) 2006-06-02 2007-12-06 Robert Bosch Gmbh Schleifhandwerkzeugmaschine sowie Vibrationsentkopplungsvorrichtung einer Schleifhandwerkzeugmaschine
DE102007000270A1 (de) 2007-05-11 2008-11-20 Hilti Aktiengesellschaft Vibrierende Handwerkzeugmaschine mit Antivibrationselement
GB2458459A (en) * 2008-03-17 2009-09-23 Trevor Timmins Vibration damping handle
DE102009014970A1 (de) * 2009-03-18 2010-09-23 C. & E. Fein Gmbh Oszillationswerkzeug mit Vibrationsdämpfung
JP2014069293A (ja) * 2012-09-28 2014-04-21 Hitachi Koki Co Ltd 打撃工具

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EP0066779A1 (fr) * 1981-06-10 1982-12-15 HILTI Aktiengesellschaft Marteau pour percer ou buriner
EP0207034A1 (fr) * 1985-06-19 1986-12-30 Eskil Sundström Poignée absorbant les vibrations
EP0246212A2 (fr) * 1986-05-12 1987-11-19 Eskil Sundström Protection contre les vibrations pour un outil portatif motorisé générateur de vibrations

Non-Patent Citations (1)

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Title
See also references of WO9416864A1 *

Also Published As

Publication number Publication date
DE69329686T2 (de) 2001-06-07
DE69329686D1 (de) 2000-12-21
EP0680399A1 (fr) 1995-11-08
EP0680399B1 (fr) 2000-11-15
WO1994016864A1 (fr) 1994-08-04

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