JPH07314352A - Vibration absorption soft grip for tool accompanying vibration, and manufacture thereof - Google Patents

Abstract

PURPOSE:To apply a process for reducing effects given to the human body by vibration generated by a tool at low cost and speedily. CONSTITUTION:Thermoplastic elastomer is coated on a metal grip base body 2 of a metal housing by insert injection moulding to form a shock absorbing layer 3. The elastomer is favorably blended with adhesive polymer, or more favorably, it is coated with an undercoat layer 31 of adhesive polymer, and a shock absorbing layer 31 is laminated on it. On a surface layer of the metal grip to be coated, a vertical groove 23, a lateral groove 22, a left spiral groove 24a, a right spiral groove 24b, an end flange 24, a recess 21, and/or a protrusion, etc., are provided solely or as they are combined. The shock absorbing layer 31 can thus be laminated without using binding agent, thereby cost and required time can be reduced.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a vibration absorbing soft grip for a tool with vibration and a manufacturing method thereof. For more information,
The present invention relates to a vibration absorbing soft grip for a tool with vibration in which a thermoplastic elastomer is adhered and fixed to the surface of a metal grip base of a machine with vibration generation without interposing an adhesive, and an insert for manufacturing the metal grip base. Regarding the molding method.

[0002]

2. Description of the Related Art The housings or casings of tools, such as electric drills, electric saws, electric sanders, electric grinders, chainsaws, air nailers or tackers, which generate vibrations upon operation are made of metal, especially aluminum. It is formed by die casting of base metal. Therefore, the vibration caused by the operation of the machine is impaired to damage the joints of fingers, wrists, elbows and shoulders and capillaries in their muscles.

As a countermeasure, a measure has been taken in which a vibration absorbing layer made of a cushioning material is attached to the surface of a metal grip with an adhesive.

[0004]

However, when a vibration absorbing layer made of a cushioning material is attached to the surface of a metal grip with an adhesive, the performance of the adhesive, that is, the reliability of the adhesive force and the cohesive force, etc. In addition to this, there is still room for improvement in durability, that is, durability and vibration resistance. In addition, the attachment with an adhesive increases the number of steps for manufacturing the grip, which is an obstacle to cost reduction.

The present invention eliminates the conventional step of attaching a cushioning material using an adhesive which is unavoidable to the cushioning means, and develops a cushioning grip in which the cushioning material is firmly attached to the grip, and a method of manufacturing the cushioning grip in one step. The purpose is to do.

[0006]

As a result of repeated studies to solve the above problems associated with the prior art, the present inventor has found the following "basic structure of product invention" and "improved structure of product invention". 1) to "improved configuration 5 of product invention", "basic configuration of manufacturing method invention" and "improved configuration 1 of manufacturing method invention" achieve the object of the present invention.

[Basic Structure of Product Invention] A vibration absorbing soft grip for a tool accompanied by vibration in which a thermoplastic elastomer is closely fixed to the surface of a metal grip base of a machine accompanied by vibration generation without an adhesive.

[Improved Structure 1 of Product Invention] The "basic structure of the product invention" in which the thermoplastic elastomer is formed of an olefin resin component and one or more elastomer components selected from an olefin elastomer and a partially crosslinked olefin elastomer. Soft grip described in.

[Improved Structure 2 of Product Invention] The soft grip described in "Basic Structure of Product Invention" and "Improved Structure 1 of Product Invention" in which the thermoplastic elastomer is at least partially a polymer having an adhesive property to metal. .

[Improved Structure 3 of Product Invention] One or more selected from the group consisting of a thermoplastic resin in which a polymer having an adhesive property to metal is modified by maleic anhydride graft and an elastomer modified by maleic anhydride graft. The soft grip described in certain "basic constitution of product invention", "improved constitution 1 of product invention" and "improved constitution 2 of product invention".

[Improved Structure 4 of Product Invention] "Basic structure of product invention" in which one or more shapes selected from a projection, a ridge, a groove and a recess are provided on the surface of a metal grip base. And the soft grip described in "Improved structure 1 of product invention" to "improved structure 3 of product invention".

[Improved Structure 5 of Product Invention] "Basic structure of product invention" and "improved structure 1 of product invention" to "improved structure of product invention" in which a flange is provided at least near the end of a metal grip base. 4) Soft grip.

[Basic Structure of Manufacturing Invention] A vibration absorbing soft grip insert molding method in which a metal grip substrate is placed in a mold for injection molding and then a thermoplastic elastomer is injected into the mold from an injection molding machine.

[Improved Structure 1 of Manufacturing Method Invention] The modified thermoplastic elastomer is injected into the mold from one of the two injection molding machines and fusion-coated on the surface of the metal grip substrate, and then the other injection molding machine. Injecting an unmodified thermoplastic elastomer containing a foaming agent from the machine to the coated surface to form a skin layer by melting the surface layer while forming a skin layer by laminating and coating, and then heating the foamed layer. The described molding method.

[Preferred Embodiment of the Invention] <Material for Soft Grip> The material forming the soft grip of the present invention is a soft thermoplastic elastomer, and is a thermoplastic polymer composed of a thermoplastic resin component and an elastomer component. Is. Its basic properties are MFR (230 ℃;
2.16kgf) Normally 10-25g / 10min, preferably 15-2
At 0 g / 10 min, this thermoplastic elastomer is a polymer which can be molded by an ordinary thermoplastic resin thermoforming device or means and has a slight rubber elasticity. The elastomer component constituting the thermoplastic elastomer may be partially cross-linked within the range in which the compatibility with the resin component is practically maintained.

The thermoplastic elastomer by itself has a sufficiently strong thermal adhesion to the metal surface of the casing of the tool. However, even if the tool is used under particularly severe conditions, a stronger adhesive force is required.To withstand this, a high-adhesion weight with a thermoplastic elastomer graft-modified with maleic anhydride is used. Combined (maleic anhydride unit content 8 to 30% by weight, preferably 9 to 25% by weight)
It is preferable to use a thermoplastic elastomer containing 5 to 30% by weight, preferably 18 to 25% by weight (composition basis).

Further, the thermoplastic elastomer of the present invention preferably contains a foaming agent. As a result, a soft grip including a porous layer having a foaming ratio of 1.5 to 6 is formed, and its vibration absorbing ability is further improved. As the foaming agent, one having a decomposition temperature higher than the molding temperature by 10 ° C. or more is selected, and examples thereof include azobiscarbimide.

<Shape of Grip> The metal grip base on which the thermoplastic elastomer forming the buffer layer of the soft grip of the present invention is laminated and fixed is a normal grip portion of an electric tool, a pneumatically operated tool or a hydraulically operated tool. Not only, but also includes the part supported by the palm. Therefore, in addition to the gun-like portion projecting laterally from the hand of the tool, the support portion located on the side surface of the body of the tool is included in the grip in the present invention.

<< Description Based on the Drawings >> Hereinafter, the shape and configuration of the soft grip of the present invention, the shape of the metal substrate, the buffer layer coated thereon, the manufacturing method of the soft grip, and the like will be described in detail with reference to the drawings. To explain.

FIG. 1 is a partially cutaway sketch of a soft grip of the present invention. In FIG. 1, 1 is the entire soft grip of the present invention, 2 is a metal base thereof, and 3 is a buffer layer coated on the base. . The overall shape of the metal grip base 2 is generally cylindrical, but an elliptic cylinder is better for easier gripping. When the surface shape is rich in irregularities rather than smooth, it is useful not only for increasing the contact area with the thermoplastic elastomer that is the layer, but also for preventing peeling.

The following is an example of the shape of various irregularities 21 to 25 provided on the surface of the metal grip base body 2 of FIG. 1. (1) A large number of small hole-shaped depressions 21 are provided, (2) ) Several grooves 22 are provided along the circumference. In order to prevent the buffer layer from pulling out, this groove is provided with (3) several grooves 23 along the generatrix. This groove is provided with a left spiral groove 24a and a right spiral groove 24b (generally "24") that intersect the bus bar to prevent rotation of the buffer layer. This groove prevents the buffer layer from both pulling out and rotating, (5) above 2
(6) The flange 25 is provided at the end (the side distant from the tool body) by combining several types of 1 to 24. This flange 25 protects the end of the buffer layer and prevents it from turning over.

<< Molding of Soft Grip 1 >> As a method of molding the soft grip 1 of the present invention, one or more kinds selected from the above various irregularities 21 to 25 are provided on the surface of the metal grip base 2. After that, the metal base 2 is placed in a predetermined position of a recess in which the outer shape of the soft grip engraved on the inner wall of the injection molding die is engraved, and then a melt of the thermoplastic elastomer is injected from the injection molding machine. It consists of a series of operations for coating the buffer layer 3 by injecting into the mold and shaping according to the outer shape of the soft grip 1.

As a modification of the molding method of the present invention, two injection molding machines are used. First, from one of them, a highly adhesive polymer is applied to the surface of the metal grip substrate 2 mounted inside the injection mold. After the undercoat layer 31 is formed, the unmodified thermoplastic elastomer is injected from the other injection molding machine onto the layer 31 to form the buffer layer 32. The highly adhesive polymer forming the undercoat layer 31 is a modified ethylene-propylene copolymer elastomer modified by maleic anhydride graft or a modified ethylene-propylene-non-conjugated diene (eg ethylidene norbornene).
Etc. consisting of a highly adhesive polymer.

A foaming agent may be added to the buffer layer 32. In that case, the skin layer is formed by heating the foaming agent to a temperature equal to or higher than the foaming temperature of the foaming agent to decompose the foaming agent and selectively melting the surface layer portion. Usually, the surface of the buffer layer 32 is melted at the foaming temperature, so that a skin layer is formed on the surface layer by the contact heating method.

Even when the buffer layer 3 is a porous layer, it is not limited to the above-described two-step injection molding, and the buffer layer 3 can be formed by single-step injection molding. However, the two-layer coating method is more preferable as the means for applying the soft coating having this structure. The reason for this is that it is useless to distribute the highly adhesive polymer even to a portion other than the surface of the buffer layer 3, and there is a possibility that the reactive group that imparts the highly adhesive property may interact with the foaming agent. To be there.

[0026]

EFFECTS OF THE INVENTION The soft grip of the present invention and the method of molding the same can exert the following effects: (1) The influence of vibration on the joints and / or capillaries of the human body can be significantly reduced (2) ) The adhesive force between the metal grip base and the buffer layer is not easily deteriorated. The reason for this is that adhesion is achieved almost all over the contact surface. (3) When the buffer layer is a foam layer, the effect of vibration on the human body can be further reduced. (4) On the surface of the metal grip base With a soft grip provided with various irregularities, the buffer layer is difficult to move unintentionally and difficult to peel off, and in addition, vibrations are canceled by the mutual interference action that can be generated from the complicated surface of the irregularities in various directions. (5) The number of molding processes is reduced. The cause is required to be able to form the buffer layer on the surface of the metal grip substrate without using an adhesive.

[Brief description of drawings]

FIG. 1 is a partial cutaway sketch of a soft grip of the present invention.

[Explanation of symbols]

1 Soft Grip of the Present Invention 2 Metallic Base of Soft Grip of the Present Invention 3 Buffer Layer Overlaid on Metallic Base of Soft Grip of the Present Invention 21 Many Provided on Surface Layer of Metallic Base of Soft Grip of the Present Invention Depressions 22 Grooves provided along the circumference of the metal base surface layer of the soft grip of the present invention 23 Grooves provided along the generatrix of the metal base surface layer of the soft grip of the present invention 24 grooves 24 Left spiral groove and right spiral groove provided so as to intersect the generatrix of the metal base of the soft grip of the invention 25 Flange provided at the end of the metal base of the soft grip of the present invention 31 Metal of the soft grip of the present invention 32. Undercoat layer coated on the substrate 32. Buffer layer coated on the undercoat layer

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Claims (8)

[Claims] 1. A vibration-absorbing soft grip for a tool accompanied by vibration, in which a buffer layer made of a thermoplastic elastomer is adhered and fixed to the surface of a metal grip substrate of a machine that generates vibration without interposing an adhesive. 2. The soft grip according to claim 1, wherein the thermoplastic elastomer is formed of an olefin resin component and at least one elastomer component selected from an olefin elastomer and a partially crosslinked olefin elastomer. 3. The soft grip according to claim 1 or 2, wherein the thermoplastic elastomer is a polymer which is at least partially adhesive to a metal. 4. The metal-adhesive polymer is one or more selected from a thermoplastic resin modified by maleic anhydride graft and an elastomer modified by maleic anhydride graft. Soft grip according to any one of. 5. The soft grip according to claim 1, wherein one or more shapes selected from a protrusion, a ridge, a groove and a recess are provided on the surface of the metal grip base. 6. The soft grip according to claim 1, wherein a flange is provided at least near the end of the metal grip base. 7. A vibration-absorbing soft-grip insert molding method in which a metal grip substrate is placed in a mold for injection molding, and then a thermoplastic elastomer is injected into the mold from an injection molding machine. 8. A modified thermoplastic elastomer is injected from one of two injection molding machines into a mold to fusion-coat the surface of a metal grip substrate, and then the other injection molding machine contains a foaming agent. The non-modified thermoplastic elastomer to
The molding method according to claim 7, wherein the surface layer is melted to form a skin layer.