MXPA97003771A - Impact tool of reduced vibration and insulator of vibration for the mi - Google Patents

Abstract

The present invention relates to a reduced vibration impact tool, characterized in that it comprises: a cylinder assembly operatively within the tool, a piston operatively positioned within the cylinder assembly, in which the piston is movable reciprocally between a forward and backward position, a means, operatively connected to the piston, for driving the piston, and an elastomeric insulator operatively coupled to the cylinder assembly and fixed within the tool, the eleastomeric insulator includes: an inner member; an elastomeric member that surrounds a circumferential periphery of the inner member, and an outer bounded non-opening member that extends radially outwardly from the elastomeric member.

Description

REDUCED VIBRATION IMPACT TOOL AND VIBRATION INSULATOR FOR THE SAME DESCRIPTION OF THE INVENTION This invention relates generally to the field of impact tools and more specifically to a pneumatic impact tool, such as a hydraulic riveter and a vibration isolator for it. Pneumatic impact tools ("air") are al power tools used in various industries. As is well known in the art, the tool housing includes an inner chamber enclosing a cylinder assembly having a piston movable reciprocally therein. Several accessories can be mounted on the tip of the tool. As compressed air enters the inner chamber of the housing from the tool handle, the piston alternates forward in the cylinder assembly until it hits with an attachment, which has been mounted on the tool tip and the fitting then makes impact with a piece of work. The action of hitting the piston on the accessory causes the piston and cylinder assembly to retract, moving backward in the housing towards the handle. In this way, it is advantageous to provide a vibration isolator that can operate to absorb the vibration transmitted to the tool handle and in turn to the operator, due to the backward movement of the piston and cylinder assembly. It is also advantageous to provide a vibration isolator that can be used with existing pneumatic impact tool construction and that employs a minimum number of components. U.S. Patent 4,776,408, issued October 11, 1988 to El in et al., Discloses a pneumatic impact tool having a cushion assembly for cushioning the repeated recoil of a hammer piston. The cushion assembly comprises a plurality of parts, including a sub-assembly that dampens the energy dissipation and a coil spring sub-assembly that stores energy arranged in series to operate independently and simultaneously to cushion the backward movement of the piston. U.S. Patent 5,441,192, issued August 15, 1995 to Sugita et al., Discloses a fastener of a driving tool, which includes a ring stop which functions as a shock absorber of a piston to prevent the "double actuation" of the tool. The ring stop is placed inside the forward end of the cylinder, forward of the piston. As the tool is operated, the piston will be propelled forward, hitting the stop, which then moves forward preventing a repeated impulse from the piston. U.S. Patent 5,400,860, issued March 28, 1995 to Best et al., Discloses an apparatus for reducing the transmission of vibration in hand tools. The apparatus is formed of a multitude of components, including a truncated male cone portion, the tip of which is located in front of a female bed and in which the base of the male portion is attached to the handle of the tool and the female portion is attached to the end? e work of the tool. Retained between the tip of the male portion and the female portion there are three rubber balls. As the female portion moves relative to the working end of the tool, the rubber balls act as vibration isolators. U.S. Patent 5,407,018, issued April 18, 1995 to Henry, discloses multi-part noise and vibration attenuation means, interposed between the front end of the housing of a hollow tool and the alternating impact member. The attenuation means has a laminar configuration formed with a first outer layer of solid elastomeric material, an inner layer of rigid metal and a second outer layer of the solid elastomeric material.

It is an advantage of the present invention to provide a pneumatic impact tool, able to reduce the vibration transmitted from the tool to the tool operator. It is another advantage of the present invention to provide an elastomeric insulator for use with a pneumatic impact tool, which is durable, has optimum oil resistance and wear and which provides superior damping value, while maintaining the "touch" It is another advantage of the present invention to provide a method to reduce the vibration transmitted from the handle of a pneumatic impact tool to the operator by providing an elastomeric insulator, which is formed of minimal components and which is inexpensive It is still another advantage of the present invention to provide an elastomeric insulator for use with a pneumatic impact tool, which can be easily integrated into existing pneumatic impact tool technology.The above features and other features and advantages of the present invention, will be apparent and the following more particular description of a preferred embodiment of the invention, as illustrated in the accompanying drawings. BRIEF DESCRIPTION OF THE DRAWINGS The preferred exemplary embodiment of the present invention, hereinafter will be described in conjunction with the accompanying drawings, in which similar reference designations mean similar elements, and: FIGURE 1 shows a view in a separate section of the impact tool of the elastomeric vibration isolator according to a preferred embodiment of the present invention. FIGURE 2 shows a front view of the elastomeric vibration isolator according to a preferred embodiment of the present invention. Figure 3 shows a cross-sectional view, taken along line 2-2 of FIGURE 2, of the elastomeric vibration isolator according to cor <; a preferred embodiment of the present invention. Now with reference specifically to the drawings, there is illustrated a reduced vibration impact tool generally designated as 10. The impact tool 10, can be any manual, piston-driven tool such as a chisel hammer, a hammer, a rammer, a pneumatic hammer, a hydraulic riveter or similar. The tool can have several types of handles, such as a gun clamp or a straight line. For purposes of illustration, the present invention will be described in terms of a pneumatic riveter, having a gun holder. Now with reference to Figure 1, the tool comprises a housing 11 with an inner chamber 12, a handle portion 13 and a tip portion 14. The handle portion 13 includes a regulator 15, which functions to control the operation of the tool 10. In this illustration, the regulator 15 controls the compressed air flow of assembly 16 for the 1G power tool. Positioned along the longitudinal axis of the inner chamber 12 is the cylinder assembly 17, which is formed of the cylinder housing 18 and the cylinder 19. The cylinder housing 18 is positioned adjacent the inner surface of the housing 11 and is extends beyond the housing 11. The cylinder 19 is movable reciprocally within the distance of the cylinder 18 and extends beyond the cylinder housing 18. The fastener 20 is fitted over the tip portion of the exposed cylinder 21 to provide a point of attachment for various accessories, depending on the workpiece tool 10 that is used with it. Moving reciprocally from a forward position, impacting the fastener 20 and a rearward position proximate to the handle portion 13 is a piston 22. The impact force of the piston 22 drives the fitting, in this example, a hydraulic rivet attachment. Placed inside the inner chamber 12 of the housing 11, separated from the tip portion 14 and close to the handle portion 13, there is an elastomeric vibration isolator 23. The vibration isolator 23 is formed of an inner member 24, an elastomeric member 25 and an outer member 26. The inner member 24 is preferably formed of a material having the characteristics of steel and disc-shaped and having an aperture. 27 to receive a fastener such as a screw cap. Surrounding the circumferential periphery of the inner member 24 is the elastomeric member 25, the working component of the vibration isolator 23. The elastomeric member 25 is preferably formed of a neoprene elastomeric rubber, although other materials are recognized. The use of neoprene rubber provides oil resistance and optimum durability. A plurality of openings 28 are molded in the elastomer body to allow air passage. A flange is also molded into the elastomeric member to improve damping of vibration. Encompassing the elastomeric member 25 there is an outer member 26, which is similar to the inner member 24, is preferably formed of a material having the characteristics of the steel. The outer member 26 includes a projection 29, which provides a second point of attachment for the vibration isolator 23. When placed operatively within the housing 11, the inner member 24 will be attached to the rear portion of the cylinder assembly 18 by means of a screw that passes through the opening 27 and the outer member 26, will be attached to the handle 13 by means of the projection 29. In this way, the elastomeric vibration isolator 23 elastically couples the cylinder assembly 17 to the handle portion 13 of housing 11, allowing relative movement between the two, resulting in insulation of the handle and a reduction in vibration transmitted to the operator. Now that one is familiar with the construction of the impact tool and the elastomeric vibration isolator of the present invention, the method of operation will be described. In practice, the operator of the tool will press control 15, engaging assembly 16 and initiating the flow of compressed air through handle 13 into cylinder assembly 17. The force of the compressed air causes the piston 22 to alternate forward inside the cylinder 19 until it impacts with the attachment held by the fastener 20. This striking action causes the piston 22 and the cylinder 19 to alternate in a reverse direction. towards the handle 13 and to the operator of the tool. Without the elastomeric vibration isolator 23, the cylinder 19 would hit the handle 13 directly and this vibration would be transmitted to the operator of the tool. However, in the tool of the present invention, the recoil movement of the cylinder 19 is absorbed by the elastomeric member 25 of the insulator 23 and the handle 13 is therefore insulated from vibration. Lae described modalities er. present, have been discussed for the purpose of familiarizing the reader with the novel aspects of the invention. Although the preferred embodiments of the invention have been shown, many changes, modifications and substitutions can be made by one of ordinary skill in the art without necessarily departing from the spirit and scope of the invention as described in the following claims.

Claims (8)

1. CLAIMS 1. A reduced vibration impact tool, characterized in that it comprises: a housing having an inner chamber; a cylinder assembly operatively assembled within the interior chamber of the housing; a piston operatively positioned within the cylinder assembly, in which the piston is movable reciprocally between a front and rear position; means, operatively connected to the piston, for driving the pistcr .; a handle operatively connected to the housing; and a fixed elastomeric insulator within the inner chamber of the housing, the elastomeric insulator fixed at a point for the cylinder and at a second point to the handle to absorb the vibration caused by the backward movement of the piston.
2. 2. The impact tool according to claim 1, characterized in that the means for driving the piston is compressed air.
3. The reduced vibration impact tool according to claim 1, characterized in that the elastomeric insulator comprises: an inner disk member having an opening extending therethrough; an elastomeric member surrounding a circumferential periphery of the inner disk member, the elastomeric member having a plurality of openings extending therethrough; and an outer member fixed to a circumferential periphery of the elastomeric member, wherein a protrusion of the outer member extends outwardly from the inner disc member.
4. The impact tool according to claim 3, characterized in that the inner and outer members are formed of steel and the elastomeric member is formed of neoprene rubber.
5. 5. An elastomeric insulator for use in a reduced vibration impact tool, characterized in that: an inner disk member having an opening extending therethrough; an elastomeric member surrounding a circumferential periphery of the inner disc member, the elastomeric member has a plurality of openings extending therethrough; and an outer member fixed to a circumferential periphery of the elastomeric member, wherein a protrusion of the outer member extends outwardly from the inner disc member.
6. 6. The elastomeric insulator according to claim 5, characterized in that the inner and outer members are formed of steel and the elastomeric member is formed of neoprene rubber.
7. 7. A method for reducing vibration transmitted from a handle of an impact tool to an operator of the hydraulic riveter, the method is characterized in that it comprises the steps of: providing an impact tool having: a housing having an inner chamber; a cylinder assembly operatively assembled within the interior chamber of the housing; a piston operatively positioned within the cylinder assembly, wherein the piston is movable reciprocally between a forward and rearward position; means, operatively connected to the piston for driving the piston; and a handle operatively connected to the housing; providing an elastomeric insulator comprising: an inner disk member having an opening extending therethrough; an elastomeric member surrounding a circumferential periphery of the inner disc member, the elastomeric member has a plurality of openings extending therethrough; and an outer member fixed to a circumferential periphery of the elastomeric member, wherein a protrusion of the outer member extends outwardly from the inner disc member; and fixing the elastomeric insulator, inside the inner chamber of the housing, to each of the cylinder assembly and the handle to absorb the vibration caused by the backward movement of the piston. The method according to claim 7, wherein the step of fixing the elastomeric insulator within the housing is characterized in that it also includes the step of: fixing the inner member to the cylinder assembly by means of a screw that passes to through the opening of the inner member; and fixing the projection of the outer member to the handle.