EP2033744A1

EP2033744A1 - Grip for tool or the like and method of producing the same

Info

Publication number: EP2033744A1
Application number: EP07743187A
Authority: EP
Inventors: Yasuaki c/o Vessel Industrial Co. Ltd. TAGUCHI; Jiro c/o Vessel Industrial Co. Ltd. TAGUCHI
Original assignee: Vessel Industrial Co Inc
Current assignee: Vessel Industrial Co Inc
Priority date: 2006-06-28
Filing date: 2007-05-11
Publication date: 2009-03-11
Also published as: WO2008001552A1; EP2033744A4; JPWO2008001552A1; CN101466505A

Abstract

A grip for a tool or the like, which is easy to grasp and which increases transmission efficiency of a rotary torque from a hand and fingers and a method of producing thereof. The grip has a core (2) fitted into a handle of the tool or the like, grip members (3) fitted into an outer periphery of the core (2) and each having a double layer structure having a grip inner layer (3A) and a grip outer layer (3B) , and an elastic layer (4) placed between the grip inner layer (3A) and the grip outer layer (3B) and enabling deformation of the grip outer layer (3B) when the grip is grasped by a hand. In a plurality of positions in a circumferential direction and a longitudinal direction of the grip, bridge sections (3C, 3D) radially projecting from the grip inner layer (3A) are integrally formed with the grip inner layer (3A) . The elastic layer (4) is formed between the bridge sections, and the grip outer layer (3B) is formed integrally with the bridge sections among outer ends of the bridge sections.

Description

TECHNICAL FIELD

The present invention relates to a grip of a driver, a manually operated tool or the like and a method of producing the same.

BACKGROUND ART

Conventionally, a grip of a driver has a handle covered with hard resin, an anti-slip groove or irregular portions formed on an outside surface thereof, and a rubber layer and a foam resin layer provided thereon (see, for example, Patent Document 1).
Patent Document 1: Japanese Unexamined Patent Application Publication(translation of PCT Application) No. JP-A 08-501026 (1996 )

DISCLOSURE OF THE INVENTION

PROBLEMS TO BE SOLVED BY THE INVENTION

However, the grip having the handle covered with the hard resin has following problems. Even in the case where a strong rotary torque is to be applied to the grip, then a surface is slippery and a user's finger hurts soon, which constitutes an obstacle to a long-time operation. Furthermore, with the grip including the rubber layer and the foam resin layer, a torque in a rotational direction is used to compress and deform the resin, which makes it disadvantageously difficult to transmit the torque to axial rotation.
It is an object of the present invention to provide a grip of a tool or the like easy to grasp and capable of improving efficiency of transmitting a rotary torque from a finger and a method of producing the same.

MEANS ADAPTED TO SOLVE THE PROBLEMS

To attain the object, the present invention provides a grip of a tool or the like including: a core fitted into a handle of the tool or the like; an inner-outer dual structure grip member fitted into an outer periphery of the core, and including a grip inner layer and a grip outer layer; and an elastic layer placed between the grip inner layer and the grip outer layer, and enabling deformation of the grip outer layer when the grip is grasped, wherein bridge sections protruding from the grip inner layer are formed integrally with the grip inner layer in a plurality of portions in a circumferential direction of the grip, respectively, the elastic layer is formed between the bridge sections, and the grip outer layer is formed integrally with the bridge sections among outer ends of the bridge sections.
With this constitution, it is possible to efficiently transmit a rotary torque to the handle of the tool or the like via the bridge sections while the elastic layer makes the grip outer layer deformable when the grip is grasped.
The rotary torque is transmitted by direct transmission by means of the bridge sections and secondary transmission in which the rotary torque is transmitted in a state in which the elastic layer is pressed against the bridge sections and compressively deformed.
The bridge sections may be only dotted around in a longitudinal direction and a circumferential direction of the grip, may be only continuous in the longitudinal direction of the grip or may be a combination of the both.
Furthermore, a producing method according to the present invention is a method of producing a grip of a tool or the like, including: while a divisible die including a die cavity for forming a grip of a tool or the like, a core space for arranging a core in the die cavity, and an injection port for injecting two types of resins in the die cavity, a plurality of pins being arranged on the die from an outside surface of the die cavity toward the core space is used, injecting a first resin from the injection port to form bridge sections connecting a grip inner layer to a grip outer layer around the pins while forming the grip inner layer and the grip outer layer on a surface of the core and on a outer periphery surface of the die cavity; and injecting a second resin from the injection port to form an elastic layer by surrounding the bridge sections between the grip inner layer and the grip outer layer.

EFFECTS OF THE INVENTION

According to the present invention, a grip of a tool or the like easy to grasp and capable of improving an efficiency of transmitting a rotary torque from a finger can be obtained.

BRIEF DESCRIPTION OF THE DRAWINGS

[Fig.1]Fig.1 is a cross-section view of a first embodiment of a grip according to the present invention.
[Fig.2]Fig.2 is a vertical cross-section view of the grip.
[Fig.3]Fig.3 is a perspective view of the grip.
[Fig.4]Fig.4 is an other perspective view of the grip.
[Fig.5]Fig.5 is a cross-section view of a second embodiment.
[Fig. 6] Fig. 6 is a cross-section view showing one example of die for use in manufacturing a grip.

DESCRIPTION OF REFERENCE NUMERALS

S Handle
1 Grip
2 Core
3A Grip inner layer
3B Grip outer layer
4 Elastic layer
5 Trough hole
8,9 Die
10 Pin
11 Die cavity
12 Core space
13 Injection port

BEST MODE FOR CARRYING OUT THE INVENTION

Embodiments of the present invention will be described hereinafter based on the drawings.
Figs. 1 and 2 show a first embodiment of the present invention. A grip 1 includes a core 2 fitted into and attached into a handle S of a tool or the like, a grip member 3 of an inner-outer dual structure including a grip inner layer 3A arranged to surround the core 2 externally around the core 2 and a grip outer layer 3B formed integrally with this grip inner layer 3A, and an elastic layer 4 placed between the grip inner layer 3A and the grip outer layer 3B of the grip member 3 and enabling deformation of the grip outer layer 3B when a user grasps the grip 1.
Bridge sections 3C protruding radially outward of the grip inner layer 3A are formed integrally with the grip inner layer 3A in a plurality of portions in a circumferential direction of this grip, respectively. The elastic layer 4 is formed between the bridge sections 3C and the grip outer layer 3B is formed integrally with outer ends of the bridge sections 3C between outer ends of the bridge sections 3C.
An instance in which the bridge sections 3C are arranged so that the elastic layer 4 is divided into a plurality of segments in the circumferential direction of the grip 1 between the grip inner layer 3A and the grip outer layer 3B is shown as shown in Fig. 1 by way of example. While Fig. 1 shows an instance of dividing the elastic layer 4 into two, the elastic layer 4 may be divided into two or more, for example, four.
The grip member 3 is configured so that the grip inner layer 3A, the grip outer layer 3B, and the bridge sections 3C are made of resin higher in hardness than the elastic layer 4 but lower in hardness than the core 2, and so that a circumferential width of each of the bridge sections 3C is larger than thicknesses of the grip inner layer 3A and the grip outer layer 3B.
The core 2 is made of resin higher in hardness and higher in melting point than resin constituting the grip member 3. Examples of the resin constituting the core 2 include polypropylene, nylon, and ABS.
By forming the core 2 out of the harder resin than that of the grip member 3, it is ensured that a rotary torque from the grip member 3 can be transmitted from the core 2 to the handle S of the tool or the like. Furthermore, by constituting the core 2 out of the high melting point resin, the grip member 3 can be formed by insert injection molding the resin lower in melting point than the core 2 around the core 2.
The grip member 3 is made of thermoplastic elastomer that can be injection molded, e.g., olefin or styrene elastomer or rubber high in repulsive force, more preferably styrene elastomer.
The grip member 3 is formed out of the above-stated elastomer to have a JIS-A hardness of 55° plus or minus 15°.
Similar resin to the elastomer can be used as resin constituting the elastic layer 4. In this case, the elastic layer 4 is constituted out of the resin to have a JIS-A hardness of 10° plus or minus 5°. By doing so, the elastic layer 4 elastically supports the less deformable grip member 3 and appropriate softness without having a pain in the finger can be obtained. It is to be noted that gel resin or the like can be used to form the elastic layer 4.
As shown in Fig. 2, the grip member 3 and the elastic layer 4 are arranged over almost an entire length of the grip 1 of the tool or the like in a longitudinal direction of the grip 1. The grip member 3 is integrally fitted into an annular groove 2a formed on an outer circumferential surface of the core 2 so as not to slip in the longitudinal direction of the grip 1.
As shown in Fig. 1, the outer circumferential surface of the core 2 and an inner circumferential surface of the grip inner layer 3A are engaged with each other by anti-rotation engagement portions 2b and 3a that are radially irregular portions so that the core 2 and the grip inner layer 3A rotate integrally in the circumferential direction of the grip 1. The anti-rotation engagement portions 2b and 3a are particularly formed between the bridge sections 3C and the core 2.
Moreover, it is estimated that slipping between grip inner and outer layers 3A and 3B and the elastic layer 4 is prevented by multiple functions of fusion bonding (adherence) between resin surfaces by integral molding, an anchoring effect produced by the bridge sections 3D arranged to be dotted around, and an effect of restricting the movement of the elastic layer 4 by pressing the elastic layer 4 against the bridge sections 3C (walls) arranged either continuously or intermittently and by covering the elastic layer 4 with the bridge sections 3C, 3D between the grip inner and outer layers 3A and 3B in the form of cells.
Radially irregular engagement portions 3b or 4a are formed in a plurality of portions in a circumferential direction of the grip inner layer 3A or the elastic layer 4, respectively (see Fig. 1). Likewise, radially irregular engagement portions 4b or 3c are formed in the plurality of portions in the circumferential direction of the elastic layer 4 or the grip outer layer 3B, respectively (see Fig. 1). Anti-slip concave portions 3d are formed to be arranged appropriately on an outside surface of the grip outer layer 3B. The anti-slip concave portions 3d of an appropriate shape such as a groove shape or a concave shape are adopted.
As shown in Fig. 2, the bridge sections 3C are cut halfway along the longitudinal direction of the grip 1 into an intermittent state and the elastic layer 4 is arranged in each cut portion. Namely, the bridge sections 3C are arranged to be dotted around in both the circumferential direction and the longitudinal direction of the grip 1. The bridge sections 3C may be arranged to be continuous in the longitudinal direction of the grip 1.
Bridge sections 3D lower in volume than the bridge sections 3C and dotted around in the longitudinal direction of the grip 1 are provided between the two bridge sections 3C. In the present specification, the bridge sections 3C continuous or intermittent in the longitudinal and circumferential directions of the grip 1 and high in volume are referred to as "main bridge sections" whereas the bridge sections 3D dotted around and lower in volume than the bridge sections 3C are referred to as "sub bridge sections". It is noted, however, that an intermittent state is a state in which one directivity is recognizable in a dotted state.
Each of the sub bridge sections 3D is formed as a cylindrical column penetrating from the grip inner layer 3A through the elastic layer 4 and reaching the grip outer layer 3B. A through hole 5 of each of the cylindrical sub bridge sections 3D is formed to be open outward of the grip member 3. As shown in Fig. 1, each of the sub bridge sections 3D includes a first sub bridge portion 3D1 having the through hole 5 (axial center of the cylinder) oriented in a radial direction and a second sub bridge portion 3D2 having the through hole 5 in parallel to that of the first sub bridge portion 3D1. The second sub bridge portions 3D2 are formed symmetrically (or can be formed asymmetrically) on both sides of each first sub bridge portion 3D1. The second sub bridge portions 3D2 may be formed radially (all of the second sub bridge portions 3D2 may be formed radially) similarly to the first sub bridge portions 3D1.
Each of the sub bridge sections 3D is formed so that cylindrical bridge-like portions connected to the grip inner and outer layers 3A and 3B are thicker, thus ensuring strength of connection between the grip inner and outer layers 3A and 3B.
Each of the through holes 5 is a straight hole having a diameter of 1 mm to 2 mm or a tapered hole ( inclination after taking out a pin) spreading from radially inward to radially outward. The through holes 5 are formed while the bridge sections 3D are formed to be dotted around. As incidental effects of the through holes 5, the slipping of the grip 1 is prevented and radial deformation of the sub bridge sections 3D is suppressed. The through holes 5 can be formed into a circular, an angular or the other shape.
The sub bridge sections 3D are arranged at such positions that a pitch of the sub bridge sections 3D is variable in the longitudinal direction and/or the circumferential direction of the grip 1. The sub bridge sections 3D are arranged particularly at a close pitch in regions in which a torque transmitted from the handle of the grip is high and at a rough pitch in regions in which the transmitted torque is low (for example, the pitch is appropriately set in a range of 5 mm to 20 mm).
Fig. 3 shows that the sub bridge sections 3D are arranged intermittently along the longitudinal direction of the grip 1 into a plurality of lines (three lines). In this case, the pitch of the sub bridge sections 3D in each line is set lower on a tip end side of the grip 1 and higher on a rear end side thereof. Such bridge sections 3D are formed symmetrically in two portions in the circumferential direction of the grip 1.
Fig. 4 shows that the sub bridge sections 3D are arranged in two lines and that the sub bridge sections 3D in the two lines are arranged into a generally X shape. In this case, the pitch of the intermittently arranged sub bridge sections 3D is set lower on the tip end side of the grip 1 and set higher on the rear end side thereof. Such sub bridge sections 3D are formed symmetrically in two portions in the circumferential direction of the grip 1.
The intermittent arrangement shape of the sub bridge sections 3D can be set to an appropriate shape such as a Y shape, a W shape or the other shape. In that case, it is preferable that the arrangement pitch of the sub bridge sections 3D is set dense in regions in contact with the finger serving as a principal part transmitting the torque of the grip 1 and set rough in auxiliary regions on a fingertip side.
Fig. 5 shows a second embodiment. Main bridge sections 3C intermittent (or continuous) in the longitudinal direction of the grip are formed in two portions in the circumferential direction of the grip, respectively. Two second sub bridge portions 3D2 each having the through hole 5 (axial center of the cylinder) in parallel to one diametral line are formed between the two main bridge sections 3C. Rod protrusions 3E protruding from the grip outer layer 3B to the elastic layer 4 halfway along the radial direction are formed between each of the main bridge sections 3C and each of the second sub bridge portions 3D2 and between the two sub bridge portions 3D2, respectively. A concave portion 5' open outward is formed in each of the rod protrusions 3E. Namely, the grip outer layer 3B enters the elastic layer 4 to thereby form bottomed cylinders.
In the grip 1 according to the second embodiment, in the case where the grip outer layer 3B and the elastic layer 4 are deformed radially inward by a stress from radially outside, tip ends of the rod protrusions 3E between the second sub bridge portions 3D2 abut on the outside surface of the grip inner layer 3A, thereby suppressing or preventing the grip outer layer 3B from being further elastically deformed. It is to be noted that first sub bridge portions 3D1 may be formed either in addition to or in place of the second sub bridge portions 3D2.
The embodiments of the present invention are constituted as stated above. With the constitutions shown in these embodiments, the outside surface is deformed into a concave shape by a stress applied from the fingers, thereby increasing a contact area to lessen the pain in the fingers, fitting the grip in the hand to facilitate user's grasping the grip, and making it possible to efficiently transmit the rotary torque from the grip member 3 to the handle S of the tool or the like.
The present invention can particularly lessen hand fatigue by allowing the grip 1 to take on cushioning characteristic and can improve transmission efficiency of rotary torque. For example, to simply lessen hand fatigue, it suffices to provide the elastic layer 4 between the grip inner layer 3A and the grip outer layer 3B. In this case, however, in the case where the rotary torque is to be transmitted, then most of the rotary torque applied to the grip is consumed by compression and deformation of the elastic layer 4 in the circumferential direction, and only remaining torque is transmitted to the handle S via the core 2. Namely, unless the elastic layer 4 is sufficiently compressed and deformed in the circumferential direction of the grip, the torque is not transmitted to the core 2, resulting in an increase in torque transmission loss.
Therefore, according to the present invention, the bridge sections that can ensure transmitting the torque are provided, and the bridge sections are arranged to be dotted around at dense pitch in regions in which it is necessary to increase the transmission torque and at rough pitch in regions in which the transmission torque may be low, thereby reducing the torque transmission loss and lessening hand fatigue. Due to this, the dotted arrangement of the bridge sections is set in light of the balance between a function of further lessening hand fatigue and a torque transmission improvement function.
Fig. 6 shows an example of dies used for a method of producing the grip 1. The core 2 is arranged in a core space within dies 8 and 9 that include a die cavity 11 for forming the grip 1, the core space 12 for arranging the core 2 in this die cavity 11, and an injection port 13 for injecting two types of resins into the die cavity 11 and that enable vertical division. A plurality of pins 10 is arranged toward this core 2 in parallel to a direction orthogonal to a division surface 14 on which a die is divided into the upper and lower dies 8 and 9, thereby drawing the grip 1 from the dies 8 and 9. Arrangement and density of the pins 10 are set to correspond to the arrangement and densities of the above-stated sub bridge sections 3D and through holes 5, respectively.
In the producing method according to the present invention, the core 2 formed in advance at a different step is disposed into the core space 12 within the upper and lower dies 8 and 9, positioned by the pins 10, and molded by integral molding method, e.g., a sandwich molding method using a color mixture molding machine.
This sandwich molding method is to form the grip 1 by injecting the resin constituting the grip member 3 and the resin constituting the elastic layer 4 into the die cavity 11 between the circumference of the core 2 disposed within the upper and lower dies 8 and 9 and the inside surfaces of the dies 8 and 9 from two injection sections of the color mixture molding machine via the same nozzle. First, a given amount of the resin constituting the grip member 3 is injected. Next, a given amount of the resin constituting the elastic layer 4 is injected. As a result, the previously injected resin constituting the grip member 3 is hardened in portions facing the dies 8 and 9. The subsequently injected resin constituting the elastic layer 4 is filled up in the die cavity 11 while portions of the previously injected resin are still hot and liquid in central portions of inner and outer layers of the die cavity 11 in the dies 8 and 9. By doing so, the resin constituting the grip member 3 is expanded on the surface of the die cavity 11 in the dies 8 and 9, and the interior of the expanded resin is filled up with the resin constituting the elastic layer 4, thus producing a three layer (sandwich) structure.
Namely, the previously injected resin flows while forming solidified coats on inner sidewalls of the dies 8 and 9 and the surface of the core 2, respectively, and forms the grip inner layer 3A and the grip outer layer 3B of the inner-outer dual structure. At the same time, the previously injected resin is caught in around the pins 10, thereby forming the bridge sections 3D around the pins 10. The subsequently injected resin is filled up into the die cavity 11 while the resin constituting the grip member 3 is hardened in the portions on the inside and outside surfaces of the die cavity 11 in the dies 8 and 9 to form the grip inner and outer layers 3A and 3B of the inner-outer dual structure as stated above. The elastic layer 4 is thereby formed. As a result, a sandwich structure in which the elastic layer 4 is sandwiched between the grip inner layer 3A and the grip outer layer 3B is provided. At this time, the previously injected resin is diffused by the respective pins 10 and filled up in the die cavity 11 while flowing in every corner of the die cavity 11. Besides, the resin constituting the grip member 3 adheres around the pins 10 and solidified, thereby forming the sub bridge sections 3D to be dotted around. In the case where a plurality of injection ports 13 is formed, the bridge sections (main bridge sections) 3C continuous in the longitudinal direction are formed in portions farther from the respective injection ports 13. By forming resin escape portions in the parts of the dies in which parts the main bridge sections 3C are to be formed, the subsequently injected resin forces out to the escape portions by the previously injected resin and intermittent portions filled with the elastic layer 4 (main bridge section intermittent portions) are formed in the parts from which the previous injected resin escapes. The elastic layer 4 fills up gaps between the grip inner and outer layers 3A and 3B and among the main bridge sections 3C, the sub bridge portions 3D1, and the second sub bridge portions 3D2 connecting the grip inner and outer layers 3A and 3B to each other.
The present invention is not limited to these embodiments but may be carried out by being appropriately changed. For example, the bridge sections may be only the sub bridge sections 3D without providing the main bridge sections 3C. Furthermore, the present invention may be applied to a ball end grip having a rear end of a large diameter ball shape. Moreover, the grip member 3 and the elastic member 4 may be formed by a molding method other than the sandwich molding method. Besides, the sub bridge sections 3D are cylindrical since being formed using the pins 10. Alternatively, each of the sub bridge sections 3D may be formed into a prismatic shape using plate members and formed as a bridge section elongated in the longitudinal or circumferential direction of the grip 1.

INDUSTRIAL APPLICABILITY

While the present invention is suited to be applied to a grip of a driver, the present invention may be also applied to a grip of the other manually operated tool or the like.

Claims

A grip of a tool or the like comprising:
a core fitted into a handle of the tool or the like;

an inner-outer dual structure grip member fitted into an outer periphery of the core, and including a grip inner layer and a grip outer layer; and

an elastic layer placed between said grip inner layer and said grip outer layer, and enabling deformation of the grip outer layer when the grip is grasped,
wherein bridge sections protruding from said grip inner layer are formed integrally with said grip inner layer in a plurality of portions in a circumferential direction of the grip, respectively, said elastic layer is formed between the bridge sections, and said grip outer layer is formed integrally with the bridge sections among outer ends of the bridge sections, and
the grip inner layer, the grip outer layer, and the bridge section of said grip member are made of a resin higher in hardness than the elastic layer but lower in the hardness than the core.
The grip of the tool or the like according to claim 1,
wherein said bridge sections are dotted around in a longitudinal direction and the circumferential direction of the grip.
The grip of the tool or the like according to claim 2,
wherein said bridge sections are arranged to be dotted around at a dense pitch in regions in which a torque transmitted from a handle of the grip is high and at a rough pitch in regions in which the torque transmitted from the handle of the grip is low so that a density of the bridge sections is variable in the longitudinal direction and/or the circumferential direction of the grip.
The grip of the tool or the like according to claim 1,
wherein said bridge sections are a mixture of bridge sections dotted around in a longitudinal direction and the circumferential direction of the grip and bridge sections continuous in the longitudinal direction of the grip.
The grip of the tool or the like according to any one of claims 1 to 4,
wherein a through hole penetrating from an inside surface of the grip inner layer to an outside surface of the grip outer layer is formed in each of said bridge sections.
The grip of the tool or the like according to claim 1,
wherein each of said bridge sections includes main bridge sections arranged in two circumferential portions, and each having a circumferential width larger than thicknesses of the grip inner layer and the grip outer layer and continuous or intermittent in a longitudinal direction of the grip, and sub bridge sections dotted around between the main bridge sections in the longitudinal direction and each having a through hole formed inside and penetrating from an inside surface of the grip inner layer to an outside surface of the grip outer layer, each of the sub bridge sections including a first sub bridge portion including a through hole oriented in a radial direction and a second sub bridge portion including a through hole parallel to the through hole of the first sub bridge portion.
A method of producing a grip of a tool or the like, comprising:
while a divisible die including a die cavity for forming a grip of a tool or the like, a core space for arranging a core in the die cavity, and an injection port for injecting two types of resins in said die cavity, a plurality of pins being arranged on the die from an outside surface of said die cavity toward the core space is used, injecting a first resin from said injection port to form bridge sections connecting a grip inner layer to a grip outer layer around said pins while forming the grip inner layer and the grip outer layer on a surface of said core and on a outer periphery surface of said die cavity; and injecting a second resin from said injection port to form an elastic layer by surrounding said bridge sections between said grip inner layer and said grip outer layer.