WO2007027981A1 - An impact tool system for reducing spalling, vibration, noise and biomechanical stress - Google Patents

Abstract

The inventors have designed a tool 1 to be struck, or a striking tool, with a fiber-reinforced polymeric disc (collectively referred to as an 'impact tool'), or alternatively, a ribbed cap with novel material and shape characteristics, that will not suffer metal spall and the attendant dangers from noise and from spalling and flying or cutting metal slivers, i.e. a catastrophic failure of part or all of a tool. By further modifying the working end of the tool, impact effectiveness can be maintained. Other tools such as impact wrenches, impact tools, jackhammers, electric hammers, air hammers, wedges, spikes, hammers, mallets or other tools being struck or striking forcibly benefit from the invention. Also contemplated is a one piece cap with rounded edges and with molded, rounded structural reinforcing ribs.

Description

INVENTION TITLE

AN IMPACT TOOL SYSTEM FOR REDUCING SPALLING, VIBRATION, NOISE AND BIOMECHANICAL STRESS

DESCRIPTION

Heading

CONTINUATION DATA

[Para 1 ] For any application into national or regional stage for which this application can be continued (or its substantive equivalent) from an earlier application, and for purposes of the United States, the resulting utility application from this provisional application is a continuation in part of PCT/US02/23448 entitled "An Anti-Spalling Combination on an Impact Tool With an Improved Holding System" and entry into the U.S. national stage of PCT/US02/23448 filed in the United States as Receiving Office pending as 10/625,149, which PCT Application PCT/US02/23448 in turn is a continuation in part of provisional applications filed on July 23, 2001 numbered 60/307,198, and 60/356,804 filed on February 13, 2002, both filed in the United States, and U.S. Provisional Application 60/596,092 filed 31 August 2005 bearing the name "An Impact Tool System for Reducing Spalling, Vibration, Noise and Biomechanical Stress" and U.S. Provisional Application 60/597,367 filed on 28 November 2005 entitled "Impact Tool With Relatively Lower Modulus Insert for Reducing Vibration and Noise." Such applications are adopted by reference.

Heading

FIELD OF INVENTION

[Para 2] This invention relates to the use of polymeric composite materials to reduce spalling, vibration, noise and biomechanical stress for hand tools that are impacted and more generally, to accomplish the same with tools such as jackhammers, electric hammers, air hammers pile drivers, and other reciprocating or repeated impact tools also referred to as impacting or impact tools. Heading

BACKGROUND

[Para 3] Continuing the development of WO 03/10052 , now pending in the United States as U.S. Patent Application 10/625,149, (referred to as the WO '052 application), the inventors set out inventions utilizing alternative modes and materials.

Heading

SUMMARY OF INVENTION

[Para 4] The inventors have designed a tool to be struck, or a striking tool, with a fiber- reinforced polymeric disc (collectively referred to as an "impact tool"), or alternatively, a ribbed cap with novel material and shape characteristics, that will not suffer metal spall and the attendant dangers from noise and from spalling and flying or cutting metal slivers, i.e. a catastrophic failure of part or all of a tool. The noise production characteristics of impact of an impacting tool (such as a ram or hammer) striking a tool to be struck, or of the tool to be struck can be modified. By further modifying the working end of the tool, impact effectiveness can be maintained.

[Para 5] One preferred mode is on a chisel (wood or cold) or any tool which is struck or rammed repeatedly. The chisel would have a striking end cut square to the shaft. The striking end or impacted end would be opposite the working end. The tool without any modification will be referred to, if needed, as the basic tool.

[Para 6] Other tools such as impact wrenches, impact tools, jackhammers, electric hammers, air hammers, wedges, spikes, hammers, mallets or other tools being struck or striking forcibly benefit from the invention. In each of these tools having an interchangeable working tool, that portion which is interchanged will be called the interchangeable basic tool. The end which contacts the material worked is the working end of the interchangeable basic tool, and the opposite end from that working end is the striking end. For a tool such as a jackhammer, air hammer, electrically actuated hammer ("electric hammer") or impact wrench, all of which tools are generally referred to and shall be referred to in this application as (an) impact tool(s) or as (an) impacting tool(s), the working end of the tool (normally contained inside the overall housing of the jackhammer or impact wrench or tool) which rams or strikes the striking end of the interchangeable basic end is referred to as the impacting end of the impact tool or impacting tool. For larger tools where the ram may not normally be interchangeable and the ram acts on the object being rammed, such as a piling, the impacting end is the striking end of the tool hitting the object being impacted.

[Para 7] In this invention, a different application and use than that in WO '052 is proposed. For impact tools or for tools having an interchangeable working tool, a disk would be positioned above the working tool, or on the impacting end of the impact tool, of a diameter approximately equal to the diameter of the striking end. Alternatively, the disk would be the diameter of the end of a striking tool, such as a hammer. The disk would be made of a material which would not spall or shatter and would still effectively perform the designated task. The disk protects the end of the tool from spalling and modifies the noise and vibration characteristics. For an application involving an impacting tool with an interchangeable working end, a disk would be positioned in between the impacting end and the striking end of the interchangeable working end approximately equivalent to the diameter of the impacting end or the striking end. Normally, the diameters are approximately the same in an air hammer, jackhammer, or electric hammer, because the interchangeable basic tool fits up into the overall housing of the air hammer, jackhammer, or electric hammer which contains the impacting end, usually the end of a ram. [Para 8] Also contemplated is a one piece cap with molded structural reinforcing ribs with rounded edges. While the concept of an overhang from the necessary striking surface of a cap is not novel, this invention contemplates that rounded edges would be used with rounded supporting ribs. Such a design reduces chipping from off-center blows, and the rounded ribs enable vectoring of energy from off-center blows to be redirected to the center of the tool shaft. This cap can be utilized for a safety driving cap which can be mounted on any object to be driven. For objects that are directly rammed, such as a piling, the rib-reinforced cap of glass fiber reinforced polymeric composite material is an alternate preferred mode of the invention. [Para 9] A combination of the just described one-piece cap with ribs and modification of the cutting end of a working end is contemplated [Para 1 0] Replacement of such disk or other shape would be contemplated.

Alternatively the material could be more fully and more permanently integrated into the striking end of a striking tool or the impacting end of an impacting tool or both. Selection of polymers and polymeric composites can be made to include lubricity characteristics. A system for automated impacters or automated repeat impacters includes polymers, polymeric composites and/or metals inserted between impacting end of the impacter and the striking end of a striking tool. This arrangement will reduce vibrations, noise, and improve ergonomics.

Heading

PRIOR ART BACKGROUND

[Para 1 1 ] Prior art: The most relevant prior art is seen in three tools marketed in various retail outlets (Figure 1). The first is a tool (Tool 1 of Figure 1) inserted into a grip. This tool does not solve the problem of spalling, but is comfortable for the hand and can furnish some hand protection. Tool 2 of Figure 1 has high transmission of force and some hand-holding advantages, but furnishes no solution to the problem of spalling after substantial use. Tool 3 of Figure 1 is a less complex and less protective version of Tool 1 of Figure 1.

Heading

OBJECTS OF THE INVENTION

[Para 1 2] One object of the invention is to prevent injury by limiting or eliminating spalling, mushrooming, and chipping.

[Para 1 3] Another object is to increase the longevity of the impact tool. [Para 1 4] Another object is to reduce the noise and thereby reduce aural hardship on a user of the impact tool.

[Para 1 5] Another object is to accomplish the above objects without significantly reducing the cutting effectiveness or impacting effectiveness of the tool compared to the same tool without the invention applied to the tool.

[Para 1 6] Another object is to reduce biomechanical and neurological damage to the arm through attenuation of impact shock.

[Para 1 7] Another object is to enable detection of potential catastrophic failure of the tool because cracks or defects will be seen before catastrophic failure. [Para 1 8] Another object is take advantage of the frequency redistribution characteristics of the invention, both aural and non-aural to improve the ergonomic effect.

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CONTINUED DESCRIPTION OF INVENTION AND MATERIALS AND PREFERRED MODE OF INVENTION DESCRIPTION OF FIGURES

Figure 1 shows old art prior to the applications by the inventors referenced in this invention. Figure 2 shows a simplified section view of a conventional pneumatic power chisel. The disk is shown as an insert.

Figure 3 shows configurations of the modified reciprocating piston and conventional chisel used in an impact chisel. The disk is shown as an insert.

Figure 4 shows the configuration of a conventional reciprocating piston and modified chisel tool with a polymer insert. The disk is shown as an insert.

Figure 5 shows the rough outline of the exterior of a ribbed cap, but is more particularly shown to illustrate the interior conformation to a hexagonally-shafted chisel.

Figure 6 shows a chisel cap with an overhang with rounded edges and rounded ribs supporting that overhang.

[Para 1 9] More generally, for use in the invention, the term polymeric composite material includes the use of fiber-reinforced polymeric composites. Davies et al, U.S. Pat. No. 5,750,620, May 13, 1997 discloses much of this family of polymeric material to which this invention refers. More generally, the polymeric composite material in this invention includes one or more compounds selected from the group of polymeric compounds having a structure such that the intermolecular distance of the structure corresponds to the intermolecular distance of the fiber crystal structure such that upon melting of said polymeric compound in the presence of the fiber, the combination results in reinforcement of the polymeric compound. Further, the polymeric material in this invention refers to all thermoplastic structural composite materials and blends of those thermoplastic structural composite materials reinforceable by continuous fibers including fibers with various interweaves or surface activity (shaping). Many examples of these thermoplastic structural composite materials and fiber interplay, as well as manufacturing techniques, are set out in "Thermoplastic Aromatic Polymer Composites: a study of the structure processing and properties of carbon fibre reinforced polyetheretherketone and related materials," Frederic Neil Cogswell (Butterworth Heinemann Publishers Ltd. 1992). Of considerable interest are fiber reinforced materials in the "Victrex" range of polymers from ICI, particularly polyethersulphone, polyphenylene sulfide, and polyetheretherketone, and the fiber reinforced nylon materials. The Victrex range of polymers are described as materials whose members are based on separating rigid aromatic units with either flexible or stiff linkages , usually ether or ketone. One of these compounds, or one or more of these compounds together is included in the description polymeric material.

[Para 20] The polymeric material and polymeric material composite may be and should be reinforced by generally longitudinal fibers or by more circular or bone shaped continuous fibers The ends of the fiber need not necessarily be connected but may closely overlap. Short fiber reinforced composites are also suitable for the preferred modes of this invention. The reinforcing material is usually carbon fiber, mineral, or glass fiber. Other reinforcing fibers for polymeric composites, such metallic fibers, including aluminum, are well-known in the art and covered by this invention. Generally, the concept is and the term continuous fiber includes, generally longitudinal fibers or more circular or bone shaped continuous fibers recognizing that the ends of the fiber need not necessarily be connected but may closely overlap. Carbon or glass fiber may preferably be used, though the invention is not limited to just those fibers. The fiber selected must be such that upon melting with the selected polymeric compound, the combination results in results in reinforcement of the polymeric compound.

[Para 21 ] Polyetheretherketone (commonly referred to as "PEEK") is the most preferable for flexural strength applications. Polyetheretherketone is an aromatic polymer whose construction consists of ether, ketone, and phenyl groups. Polyetherketoneketone is a close cousin (commonly referred to as "PEKK"). Unfilled and unreinforced polymeric composites generally have a low coefficient of friction and exhibit self-lubricating character but usually lack the strength and rigidity necessary for the contemplated application. By reinforcing the polymeric material with short or long fibers, including in various shapes, or a continuous carbon fiber, the material becomes significantly stronger. Certain materials also have self-lubricating character which is useful in the tools involving repeating impacting such as a jackhammer. A carbon fiber reinforced polymeric composite such as PEEK or polyphenylene sulfide (commonly known as "PPS") or polyethersulfone ("PES") also maintains these characteristics at sliding contact speeds making it suitable for unlubricated operations. Polymeric composite can be laminated and formed similarly.

[Para 22] Because of the hardness of the material, an optimal method of manufacturing is to cure the material in a mold that results in rouletting of the sheets so they can be parted into the selected shape more easily.

[Para 23] The bias of the fibers can be alternately set to provide a specific flexural strength, coefficient of thermal expansion, lubricity, and/or wear. Better tribological properties are gained by having the ends of the fibers as close to perpendicular to the sliding contact surface as possible. Better wear properties are gained by having the fibers parallel to the sliding contact surface. The coefficient of thermal expansion also can be tuned through selective orientation of the fibers in multiple plys since the longitudinal expansion is an order of magnitude smaller than the transverse. The preferred mode is a compromise that maintains sufficient flexural strength to resist foreign impact damage but minimizing the wear rate while matching the thermal expansion of the surrounding device.

[Para 24] Also contemplated are layers of metallics, or metallic impregnated polymeries referred to above, in conjunction with another layer of polymeric compound selected for the combination of flexural strength, durability and any necessary lubricity. High strength metals such as titanium could be used.

[Para 25] A variety of adhesives may be used to secure in an impact tool such layered object to diminish noise while preserving impact effectiveness.

[Para 26] Also contemplated is a two or three dimensional mesh of any fiber material, including a high strength metal in conjunction with a melting in one or more polymeric compounds in composition into said mesh. The reverse process of one or more high melting point polymeric compounds or polymeric composites in mesh form into which metal with a lower melting point is bled is also contemplated.

[Para 27] The key benefit of the invention relates to protection of the tool and more importantly, the worker, from attendant noise, fatigue, reduction of biomechanical stress, spalling and its consequences. The WO '052 application proposed a cap on the striking end of a working tool. The specification of WO '052 is fully adopted and incorporated by reference and assists in the understanding of the invention in this application. However, this invention specifically contemplates a broader application with either a disc insert in impact or impacting tools, or a specially designed cap with surprisingly better characteristics as next described. [Para 28] The inventors propose to use 8018 Zytel® (TM of Dupont Corp.) for the disc or insert or rounded ribbed cap material. This material is a glass fiber reinforced nylon material. It has the requisite toughness and lack of impact absorption, which characteristics are more formally and scientifically reflected in the "flexural strength" and "modulus" of the material, respectively. When combined with a proposed ribbing design, the invention with overhang and ribbed cap with controlled curvature as next described is novel because it has surprisingly less tendency to shatter than the best mode disclosed in WO '052. The preferred mode of manufacture is to injection-mold the material into a one-piece mold with the ribs integrated as projections in mold yielding, after melting the material into the mold, a shaped cap with a slightly arched impact surface, six protruding ribs supporting any overhand arranged symmetrically around the sides of the cap, and a hollow in the central portion of the cap to receive the striking end of the impact tool. The surface to be impacted of the cap preferably has a bull's eye which is raised up 0.020 inches to attempt to center the energy to the shank of the tool. Whether mounted as a cap on the tool being struck or mounted on the impacting tool, the overhang and supporting ribs enhance the performance and durability. Another mode of formulating the cap is to have a slightly arched surface on the surface to be struck which furnishes a "land" where the striking tool, such as a hammer is most likely to land, reducing the likelihood of off-center hits, particularly edge hits. The cap can then be driven to friction fit onto the impact tool. Upon striking the cap fitted onto the striking end of the impact tool, force is transmitted to the working end of the impact tool. For a cap entirely composed of Zytel or MINLON, edges should be rounded and reinforced by rounded ribs which enable distribution of energy from off-center hits. This is particularly true of any overhanging edge or an edge that is adjacent to the cap portion surrounding the circumferential end of the tool as it rounds to a circular area that is wider than the shaft and surrounding circumferential portion of the cap. The rounding referred to should be in an amount that results in a radius greater than 0.02 inches. In addition, the ribs should not have a sharp edge, and they should be rounded to the adjacent grooves so that there is not a radius of less than 0.02 inches as one moves around the side of the cap from rib to groove-between-ribs to the next rib. While WO '052 showed decorative ribs, surprisingly, it turned out that modification to those ribs, use of them to provide support and design to avoid any tight radius turns in the overhang and ribs supporting the overhang is surprisingly critical to prevent failure. Other decorative designs lower on the cap, or on the top of the cap away from the edges, do not appear to have any significant effect. Thus, sharp edges turned out to be an issue contributing to failure if located near the edge of the overhang or in conjunction with support of the overhang, which problem of edges contributing to failure this invention is designed to overcome.

[Para 29] If noise or vibration are absolute controlling factors, then the preferred mode is to use a one piece ribbed fiber-reinforced (glass, mineral or metal) polymeric composite material rounded ribbed cap. The focus is on increased thickness and less on the modulus. The impact efficiency would be immaterial for that design of this invention. The rounded ribs would be important to absorb any off center hits.

[Para 30] Elimination of sharp edges also has the benefit of enabling better force distribution and protection of the integrity of the cap, and reducing any chance of shattering from off-center hits, particularly edge hits.

[Para 31 ] The striking end may be chamfered. The chamfer is preferably rounded on top of a shaft surrounded by the rounded ribbed cap. The rounding should be not less than .02 inches radius to minimize failure and to enable distribution of shock forces.

[Para 32] The use of 8018 Zytel also represents an improvement upon the disk proposed for other varieties of impact tools. Alternate materials that appear useful are combinations or blends of polymer composite materials including combinations with 80G33L, a glass-fiber reinforced nylon material marketed by DuPont. As stated in WO '052, one of the more important characteristics of the invention was to not only reduce spalling, but also to reduce the sound, especially the "ping" sound of metal on metal strikes so injurious to hearing. An accompanying characteristic of using fiber reinforced polymers, glass or mineral, described in WO '052 is that the frequency of vibration, both audible and non-audible is redistributed. The high-frequency "ping" sound of metal on metal strikes is reduced or eliminated in two ways. First, the sound level, normally measured in decibels, is reduced, but also the frequency is reduced. Second, the shock of vibration, in part reflective of the high frequency ping of metal on metal hits, is redistributed to a lower level, substantially increasing the comfort of any hand-held tool, even before the suggested cushion grip is added. The benefit can be as much as a ten-fold reduction in magnitude of non-aural vibration. [Para 33] With the improved technology and lowering of cost and improved compactness of air compressors, an important market has developed for impact tools run by air pressure, electric rams, or motors. The inventors discussed impact tools such as jackhammers in WO '052. In this application, an improved design and more detail on their application are proposed. Impact tools rely on high pressure air available to drive a ram or turbine. Some impact tools such as a jackhammer rely on reciprocating, or back and forth, force applied through a ram. Other tools utilize cams and electromagnetically powered applications.

[Para 34] The inventors propose to insert a disc of 8018 Zytel or any other polymeric composite between a ram and the striking end of an interchangeable basic tool in an impact tool. Additionally, for any cutting, impacting, or driving tool, including impact tools that rely on reciprocating rams or turbines, the inventors propose that, because the force transmitted through the polymeric composite is slightly reduced, the included angle in the cutting edge can be increased to maintain impact effectiveness. The disk may be secured by a cap, or a one piece cap with ribs can be placed on an object being impacted where there is only a ram acting on the object, and the ram is not considered normally interchangeable. For instance, the ram on a pile driver is not normally interchanged and acts directly on a piling; a cap or disc as contemplated by this invention can be placed on the ram or on the piling.

[Para 35] For example, a typical chisel may have an included angle of 65-70 degrees. That angle has been selected over time because it represents the best compromise between preserving the edge of the chisel, because the blunter angle enables force distribution to prevent deterioration of the edge, and the most desirable included angle of zero degrees which is a knife edge. The knife edge would not hold up to continue cutting on repeated hammer blows on a chisel.

[Para 36] This invention slightly reduces the force transmitted from the hammer to the striking end of the tool shaft which in turn carries the force to the striking end and cutting edge. Thus the cutting edge can be made sharper, therefore having a lesser included angle to the cutting edge, because the force on the edge will be reduced, meaning the included angle is reduced, which in turn increases the cutting angle and edge, increasing the amount of material cut for any given impact, notwithstanding the slight reduction in force on the striking end of the working portion of the tool. The preferred mode uses a 60 degree included angle.

[Para 37] The preferred mode of the invention involves the use of material having sufficient modulus to enable adequate impact effectiveness with sufficient impact resistance to avoid irreversible deformation or fracture upon repeated impact.

[Para 38] The modulus is the ratio of a line or curve on a graph. One axis of the graph is stress measured in force per unit area (the stress can be push or pull), and the other axis is the ratio of the length of a selected standard material under stress divided by the original length of the selected standard material when there is no stress on it. Materials which do not have much distortion in length when under much stress tend to transmit energy or force in a higher ratio than materials which do distort when under stress.

[Para 39] The shape is selected for durability and sound diminution while preserving impact effectiveness. The invention enables selection of materials that cause a frequency shift in sound so that impact noise can not only be attenuated in terms of intensity in decibels, but what sound does emerge is emitted at different and usually lower frequencies that the high-pitched metallic sound that is more bothersome to an impact tool user.

[Para 40] Impact resistance involves a standard test which essentially measures the brittle quality of a material. In the traditional steel cold chisel, the modulus is very significant meaning most of the force with which the chisel is hit on the striking end is applied to the working end of the chisel. However, the disadvantage is that the impact resistance of steel is not as favorable as MINLON because the steel deforms and unfortunately deforms permanently yielding mushrooming, or spalling, and potentially chipping all of which are dangerous to the user. [Para 41 ] In a layman's terms, the higher the modulus, the tougher and more expensive the material, as a rule, the thicker it is, the more absorption of impact will occur through deformation and springiness, and the larger the area, which is preferred to be the size of the shaft, the thinner the material can be or the lower the modulus. The disk on many tools needs to be large enough that the cap or grip are not struck and degraded by off center impacts. [Para 42] The invention proposes to take advantage of the modulus of the material, and its lower modulus compared to say a steel striker, and maintain impact effectiveness, as described in the next paragraph by reducing the included angle for the cutting edge or a cutting tool, tor instance, for a chisel with the rounded ribbed cap, the top of the shaft of the chisel would have a cross-sectional area A. The rounded ribbed cap would have a thickness T over that area A. The fiber reinforced material in the rounded ribbed cap would have a modulus M, characteristics. A standard chisel might have an included angle on the cutting edge of 65-70 degrees. The inventors propose to modify that included angle to be sharper, preferably 60 degrees and then select the cross-sectional area A, the thickness of that area T and modulus M so that the impact tool as modified by the invention, cuts with not less than 50% impact effectiveness. [Para 43] For an impact tool, or a reciprocating tool such as a jackhammer, the time of cutting is the intuitive criteria. For a tool with the same number of impacts per time period, impact effectiveness would be the ratio of the amount of time (or for a chisel, the number of blows) to cut a material or perform a given task which the inventors proposed should be at least 50%: the denominator of the ratio is the time required to cut a material using the combination of the polymeric composite material, most preferably a polymeric composite disc between the ram and the striking end of the working tool applying cutting force on the impact end of the working tool, and a sharper angled cutting edge; the numerator is the time required to cut the same material without the polymeric composite material and with the normally angled cutting edge. [Para 44] The invention then yields an impact tool which is less prone to spalling and failure, is quieter, and easier to use ergonomically, but also does not lose efficiency as an impact tool.

[Para 45] Another preferred mode in conjunction with impact tools relates to an air-powered hammer ("air hammer") or electric hammer. A typical air hammer has a piston which is alternately driven by air against a working end. The piston can be spring loaded to reset the piston against the pressurized air outlet. Alternatively, the piston may be simply reset by the pressure of the tool with an interchangeable working portion held against the piece upon which work is being done. The explosive force of the release of air from the pressurized air outlet is sufficient to drive the working portion against the piece upon which work is being done and the pressure absent the pressurized air is sufficient to reset the striking end of the working portion against the piston. [Para 46] The invention proposes that a disc or cap be secured to the piston. The disc may be glued, or have a protrusion that snap fits into the end of the piston. The disc can also be an insert and references to disc in this application are meant to include an insert. A cap with a disc insert of the polymeric composite material, or a cap with polymeric composite material melted in, or a cap made wholly of the polymeric composite material may be secured to and fit upon the piston. Alternatively, the cap with a disc insert of the polymeric composite material, or a cap with polymeric composite material melted in, or a cap made wholly of the polymeric composite material may be secured to and fit upon the striking end of the working portion of the tool which is normally interchangeable. The latter has the advantage of disposability and replacement if worn. A somewhat less desirable material, MINLON may be used instead of 8018 Zytel. MINLON 11C40 (for convenience called "MINLON"). MINLON is a mineral and mineral-fiber reinforced Nylon 66 composite sold under the trademarked name of MINLON by DuP ont Corporation of Wilmington, Delaware. If a softer and less expensive material outside the central striking portion of a cap or disk is desired, ADIPRENE ™ may be used. ADIPRENE may be used for a cap with an aperture through which the harder and tougher disc protrudes. The material selected by the inventors in their most preferred mode for the cap surrounding the disk is ADIPRENE (TM), cataloged as LF 753D. The product is marketed by Uniroyal Chemical Urethane Technology Group is part of Crompton Corporation, 199 Benson Road, Middlebury, Connecticut 06749. The cap to hold the disk can be made of any number of polymers, with preference to polyamides and polyurethanes. The key is a cheaper material than 8018 Zytel or MINLON, such as ATAPRENE, HYTRIL, PELRIN, NYLON, polypropylene, or DACRON.

[Para 47] The preferable mode is to use either a flat top with a flat, slightly raised (0.020 in.) target area, or bulls eye, or to have such an amount of polymeric composite material bled in to the mold to produced the desired disk thickness and diameter to match the diameter of the striking end of the striking tool and the diameter of the shaft of the basic tool which is being used for driving or cutting. Less preferably, the same system can be used to produce a disk with polymeric composite material held by a cap of less expensive material with an aperture through which the "land" of the disc protrudes.

[Para 48] There can also be a rear disk of fiber-reinforced polymeric material to a ram, striker, or piston, opposite the impacting end, for instance in a reciprocating piston tool. [Para 49] Replacement of such disk or other shape would be contemplated. Alternatively the material could be more fully and permanently integrated into the striking end of a striking tool or the impacting end of an impacting tool or both. Selection of the polymeric material from the classes of polymers and polymeric composites can be made to include lubricity characteristics.

[Para 50] The inventors proposed to use a polymeric composite material, preferably 8018 Zytel, interior to a box wrench or any other enclosing wrench that is applied to a bolt or nut in order to protect the surface of the bolt or nut. This is particularly important for cosmetic bolts and nuts. Previously known in the art was lining a wrench, such as a pipe wrench, with rubber or making a rubber faced tool. The difficulty with rubber, in particular, and with many composites more generally, is that they do not stand up to abuse. Air driven tools also exist such as ratchet wrenches which are applied to a blot or nut. Many cars use highly polished chrome nuts for wheel lug nuts.

[Para 51 ] The inventors propose to use the polymeric composite material, preferably 8018 Zytel, to be molded into the interior of a box wrench or ratchet at the desired diameter and shape of the head of a bolt or shape of the nut. The box wrench may be manual such as that sold by Sears, Roebuck and Co. in their Craftsman® line of tools, or in a novel composition, may be part of an interchangeable group of rings that are inserted into a novel air driven tool. Using an air driven rotor applying force to a ratchet in the fashion of a Husky Model No. H0504-2 Ratchet Wrench, the inventors proposed to substitute an interchangeable ring with exterior ratchet features for the interior ratcheting mechanism of the H00504-2 Ratchet Wrench. The ring can be of a standard size. Most preferably it would have an interior that could secure from relative circular movement a polymeric composite material interior of desired diameter and shape. Upon operation of the air-powered box wrench, the interchangeable ring would be driven in the direction permitted by a ratchet pawl which can be used to reverse direction. The ring may be driven by an impact piston, preferably protected by a polymeric composite cap or disc, or by a cam or gear mechanism. Interior to the ring is a polymeric composite material that has the interior shape of a traditional box wrench. The ring for a ¹A inch box wrench might be 1 inch witfi polymeric composite material interior to the 1 inch ring reducing the opening to that of a traditional ¹A inch box wrench. For a smaller size of say a 3/8 box wrench, it would be more desirable to use less expensive metal for a ring of the same exterior dimensions as the just- mentioned 1 inch ring with the exterior ratchets, but much thicker metal to the interior so that the polymeric composite material was only used for the last 1/8 inch of sizing to the a traditional 3/8 box wrench. Less preferably for cosmetic purposes, the ring can be all metal. The ring need only be secured to the body of the air driven tool so as not to fly out from an enclosure. The simplest configuration is to insert the ring between two parallel surfaces having an aperture larger than the largest desired box wrench opening, and the two parallel surfaces being larger than or as large as the outside diameter of the interchangeable ring. The ring would have a circular groove that aligns with a protruding circular edge on the parallel surfaces. A spring loaded snap holding mechanism to secure the ring between the protruding edges and a means to secure the parallel surfaces from spreading would enable interchange of insertable rings with a box wrench interior.

[Para 52] If an impacting tool is not only contemplated to have a disk between the impacting end and the striking end of a basic interchangeable tool, the portions of the tool housing encompassing and contacting the striking end of the basic interchangeable tool can be lined with polymeric composite material to dampen and redistribute vibration and noise. For such a lining, a wear line could be color indicated toward the surface of the lining contacting the impacting tool to indicate needed replacement of the lining.

[Para 53] The advantages of this mode of the invention with the larger cushion grip are that a normal chisel shaft is considerably smaller than a person's hand and the grip enables the person to comfortably and more safely hold the chisel, in part by increasing the holding torque. The cushion grip reduces the shock to the hand and minimizes injury such as carpal tunnel or other fatigue syndrome. The invention has the advantage of redistributing vibration to lower frequencies. This applies to both aural vibration, meaning the ear is not exposed to the high pitched ring of the hammer on chisel, and to lower level vibrations of the shaft which is easier on the body. The hand feels a sense of dampening. The preferable cushion grip is a synthetic elastic material that is oil and grease resistant. There can be a disk, a cap, or a cap with flange and grip. [Para 54] The grip may also have a collar at the lower end away from the striking end toward the working end which prevents the hand from sliding down the grip to the work and furnishes a more comfortable hold.

[Para 55] The grip may be tapered.

[Para 56] The material marketed by DuPont Corporation of Wilmington, Delaware as 8108

Zytel has important characteristics of performing not only in standard atmospheric conditions, but also still being functional at higher temperature in 100% humidity, and not shattering in response to blows at -4 degrees F.

[Para 57] MINLON has been tested in the preferred mode of application with a cold chisel in a machine with a one Ib. hammer accelerated to 50 ft/sec², cutting 1/4 inch drill rod, to 3000 strikes with no apparent effect on either cutting effectiveness of the impact tool, nor on the appearance of the impact tool.

[Para 58] In a more complex mode, the grip may have the cap integrated with the grip. Even more complex is, in a complex injection mold, to insert the mineral or mineral-reinforcing, flow in the Zytel or MINLON in the area to be adjacent to the striking end of the impact tool, and then flow in the ADIPRENE to fill out the rest of the injection mold cap are and grip area.

[Para 59] Another novel aspect of the invention is to use a combination of a more sharply angled cutting edge with slightly lower modulus material for the disk. If the cutting edge is too sharp an angle and the force transmitted is too high, the edge degrades too rapidly. Thus, this invention by selection of material for the disk enables a sharper angle to the cutting edge, and correspondingly faster cutting for the sharper angle. Test results indicate that the slightly lower impact force in a given tool resulting from the use of the MINLON disk enables an adjustment to a 60 degree inclusion angle from a standard 65-70 degree angle with effectiveness only declining from 12 cutting blows for a standard-angled tool without a MINLON disk to 13 cutting blows for a 60-degree angled tool with the MINLON disk. The degradation that might occur on the sharper angled tool does not occur because some energy is lost because of the disk. This is also applicable to repeated impact tools.

[Para 60] Multiple caps for different grips may be utilized. For the cap over the disk, in the preferred mode with the disk protruding, the materials HYTRIL, PELRIN, ATAPRENE,

NYLON, polypropylene or DACRON may be used. [Para 61 ] With respect to the use of the invention in a jackhammer, normally the bit or working portion of the jackhammer is interchangeable. As stated before, in a jackhammer, the width of the later described disk would normally be coincident with the diameter of the shaft of the interchangeable working portion of the jackhammer. The jackhammer ram would strike the disk. There would be significant noise reduction. The invention also contemplates the use in a jackhammer of the same material, MINLON, to line the retaining ring, or to be the retaining ring, that aligns, the working portion of the jackhammer which is being rammed by a jackhammer ram. Noise reduction occurs by reducing the noise of the working portion of the jackhammer rattling in the end of the jackhammer from which the working portion protrudes from the main body of the jackhammer containing the ram.

[Para 62] An alternative combination of preferred mode involves a method of manufacture resulting in a novel combination in a one-piece cap for an impact tool. There are two approaches. First, the disk may be manufactured as previously described. A less expensive material for the cap or grip being used as cap and grip can be selected with a lower melting point than the material in the disk. The disk can be positioned in the mold, and the selected material for the cap (or grip) flowed into the mold yielding a disk secured in the cap (or grip). Second, using an injection molding process, a reinforcing fiber is secured, preferably by adhesive, in a centered position (referred to as "the center of the mold" regardless of its actually position in the mold; the reference being to the final cap) in that upon completion of molding, cooling and removal from the mold, will result in a fiber reinforced thermoplastic resin portion between the center impact point of a striking device and the body of the tool. The entire mold can be injected with 8018 Zytel or MINLON, with the nylon components permeating the fiber for reinforcement. Alternatively, and more cost effectively, the "center of the mold" can be initially injected with 8018 Zytel or MINLON by DuP ont of Wilmington, Delaware, and the remainder of the mold for a particular cap with ADIPRENE developed by DuPont and produced by UniRoyal Chemical, cataloged as LF 753D. Although the order of injection, i.e. from the outside to the center can be reversed, the inventors believe the initial injection of 8018 Zytel is preferable. The resulting combination is a tool, with a one piece cap having a reinforced center of Zytel, and the shaft with a working end, and the other striking end with the one piece cap, can be made with or without a grip. Further, the mold can be enlarged so that the entire cap and grip are made of 8018 Zytel in conjunction with the fiber reinforced center of the tool. [Para 63] Alternatively, thermosetting materials can be molded into the cap, or thermoplastic materials molded in according to standard techniques known to those reasonably skilled in the arts related to those materials.

[Para 64] The invention is also applicable to a spike such as wedge or a railroad spike where the invention enables quieting of noise and reduction of spalling without significantly impairing effectiveness of penetration.

[Para 65] The first method of manufacturing is to slide the cushion grip on the tool, place the disk on the tool and then mount the cap on the tool. A second method of manufacturing is to place the disk on the tool and then mount the described grip on the tool. [Para 66] A label may be put on the grip or the cap or both, or on the disk. [Para 67] The invention, using the cap or the grip is also suitable for display. [Para 68] The invention is not meant to be limited to the disclosures, including best mode of invention herein, and contemplates all equivalents to the invention and similar embodiments to the invention.

Claims

What is clai med is:

[Clai m 1 ] A powered impacting tool comprising: an impacting end on a striker for striking a working tool; and a disk made of fiber reinforced polymeric material inserted adjacent to said impacting end in order to redistribute frequency of vibration from impact and frequency of sound from impact. [Clai m 2 ] The impacting tool according to claim 1 , further comprising: said impacting tool being a tool having a reciprocating impacting end repeatedly striking a working tool through said impacting end. [Clai m 3 ] The impacting tool according to claim 2, further comprising: said impacting tool having an insertable striking end of said working tool contained in said impacting tool adjacent to said impacting end; said impacting tool having ring made of at least one fiber reinforced polymeric material for securing said striking end of said working tool. [Claim 4 ] The impacting tool according to claim 1 , further comprising: said impacting tool being a tool having a reciprocating impacting end repeatedly striking an object through said impacting end. [Clai m 5 ] The impacting tool according to claim 1 , further comprising: said impacting tool having a working tool inserted in said impacting tool; said working tool having a working end; said working tool having an impacted end impacted by said striker; said disk made of fiber reinforced polymeric material inserted adjacent to said impacting end being disposed on said impacted end of said working tool. [Claim 6 ] The impacting tool according to claims 1-6, further comprising; said impact tool being a tool for performing cutting; said impact tool having a disk of cross-sectional area A and thickness T comprised of at least one fiber-reinforced polymeric material having a modulus M; said impact tool having an interchangeable working tool end; said working tool end having a cutting edge said working tool end having a standard included angle for said cutting edge; said working tool end being modified to reduce said included angle for said cutting edge thereby making said angle more acute so that in combination with said cross-sectional area A, said thickness T, and said modulus M, characteristics A, T and M are selected so that said impact tool being modified cuts with not less than 50% impact effectiveness. [C lai m 7 ] The impacting tool according to claims 1-6 further comprising: a fiber-reinforced polymeric disc disposed on said striker opposite said impacting end of said striker. [Clai m 8] The impacting tool according to claims 1-6 further comprising: a fiber-reinforced polymeric disc disposed on said striker opposite said impacting end of said striker. [Clai m 9 ] An impact tool comprising: said impact tool having a shaft having an impacted end and a working end and a rounded ribbed cap; said ribbed cap being disposed over said impacted end; said ribbed cap being comprised of at least one fiber reinforced polymeric material; said ribbed cap having an overhang exterior to said impacted end of said shaft; said ribbed cap having ribs being disposed generally parallel to said shaft and supporting said overhang; said ribs and overhang being disposed and rounded so that any turn from one plane to another in any plane exterior to said cap of said ribs and said overhang has a curvature of not less than .05 cm. (.02 inches). [Clai m 1 0] The impact tool according to claim 9, further comprising: said cap having curvature interior to said ribbed cap adjacent to said impacted end of not less than .05 cm. (.02 inches). [C lai m 1 1 ] The impact tool according to claim 10, further comprising: a grip on said shaft. [Clai m 1 2] The impact tool according to claim 10, further comprising: said impact tool being a tool for performing cutting; said impact tool having a shaft; said impact tool having a cap of cross-sectional area A over said shaft and thickness T over said shaft and cross-sectional area A comprised of at least one fiber-reinforced polymeric material having a modulus M; said impact tool having a working tool end of said shaft on which is mounted said ribbed cap; said working tool end having a cutting edge; said working tool end having a standard included angle for said cutting edge; said working tool end being modified to reduce said included angle for said cutting edge thereby making said angle more acute so that in combination with said cross-sectional area A, said thickness T, and said modulus M, characteristics A, T and M are selected so that said impact tool being modified cuts with not less than 50% impact effectiveness. [Claim 1 3] The impact tool according to claim 12, further comprising: a grip on said shaft. [C lai m 1 4] A fluid powered wrench tool comprising: a ring contained within a cavity within said wrench; said ring having exterior teeth spaced around said ring and having interior shape corresponding to the head of a shaft desired to be turned; so that upon application of air, a reciprocating piston impacts said exterior teeth, driving said teeth repeatedly in circular fashion. [Claim 1 5] An air powered ratchet wrench tool comprising: a ring contained within a cavity within said wrench; said ring having interior teeth spaced around said ring and having interior shape corresponding to the head of a shaft desired to be turned; so that upon application of air, a reciprocating piston impacts said interior teeth, driving said teeth repeatedly in circular fashion. [C lai m 1 6] The tool according to claims 1-15, further comprising: said fiber to reinforce said fiber reinforced polymeric material being selected from the group of glass, mineral or carbon fibers.