WO2015183191A1

WO2015183191A1 - Inertia moment screwdriver

Info

Publication number: WO2015183191A1
Application number: PCT/SG2014/000246
Authority: WO
Inventors: Yongyan Liu; Haiyan Liu
Original assignee: Forevertrust International (S) Pte. Ltd.
Priority date: 2014-05-30
Filing date: 2014-05-30
Publication date: 2015-12-03

Abstract

An inertia moment screwdriver is provided, which comprises a composite structure having an inertia moment tool holder (3), wherein a ball handle (2) is rotatable by being positioned with a palm center, plastic sleeves (4), (5) which are tightly sleeved on the tool holder (3) may be clamped to rotate by fingers, a pair of bolts (6) for producing a turning couple are correspondingly screwed into a connection block (8) and connected with a central portion of the tightly pressed tool holder (3). When a torque generated by hand screwing is insufficient, the fingers are spread to apply a force to turn the plastic sleeves (9) covering the bolts (6), and threads can be tightened or loosened by the increase of the torque. When the torque is small in the rotation process, the counterweight bolts (6) drive the tool holder (3) to perform a circular motion speed up the process.

Description

INERTIA MOMENT SCREWDRIVER

FIELD OF THE INVENTION

The present invention relates to an inertia moment screwdriver, in particular to a screwdriver applicable to large-size threads, which belongs to a screwdriver tool.

BACKGROUND ART

Screwdriver is a tool which is used for turning a screw so as to force the screw in position or detach the screw. A manual ratchet screwdriver in the prior art is equipped with a plastic handle and a ratchet mechanism. The ratchet mechanism drives an iron bar for clamping screw to idle clockwise or counterclockwise, and the mechanical ^' energy is improved by the idle rotation. But the ratchet mechanism is relatively complex and cannot effectively increase the speed of tightening or loosening the screw.

The Chinese invention publication CN 101468456A discloses a new screwdriver, wherein a handle of the screwdriver is provided with a through hole perpendicular to an axial line of the handle, and when in use, a small rod penetrates through the through hole. The method for increasing the torque force by elongating a moment arm does not take the moment of inertia into consideration. As a tool holder and the small rod are integrally formed, the rotation angle of hand holding is limited, and hence the comprehensive rotation cannot be achieved.

SUMMARY

The objective of the present invention is to fill in the gaps in the prior art of application tools and provide a tool for increasing the rotary moment by increasing the moment of inertia, which has a tool holder rotatable in a range of 360°, is convenient and practical in manual operation, has a low cost, and is applicable to tightening or loosening of large threads and rusty screws.

In order to achieve the objective, the present invention adopts the following technical solution. According to an aspect of the present invention, a screwdriver head fixed on the tool holder may be a cross screwdriver head, a slotted screwdriver head, a hexagon socket screwdriver head or a special screwdriver head; a linear moment arm in the central portion of the tool holder is formed by a pair of bolts equipped with counterweight nuts; a connection block is screwed in and tightly fixed on the tool holder, and covered with a plastic sleeve outside as considered from the aspects of hand feeling and aesthetics; a ball handle positioned by a palm is rotatable with respect to the tool holder, the plastic sleeve sleeved on the tool holder is divided into two portions to form a step, such that the thumb can cooperate with the forefinger (the middle finger) to rotate the tool holder.

A screwed hole of the rectangular connection block transversely runs through a working position of the inertia moment screwdriver; a through hole vertically runs through the screwed hole; and the tool holder is tightly fitted with the through hole of the connection block. There is a pair of full thread bolts, each of which is screwed into a nut and pressed against the nut by a bolt head. As known from the theorem about moment of inertia, M = = ιηι^β, when the mass m and the bolt length r are large, the moment of inertia j is large, and under the same rotation angle acceleration β, the torsion moment M produced thereby is large, such that the tool holder and the screwdriver head can be driven more easily to rotate. The bolts equipped with the counterweight nuts are respectively screwed into the connection block to tightly press a cylindrical surface of the tool holder. A further preferred structure is that the bolts are respectively screwed into a plane of a milled notch of the tool holder.

The plastic sleeve is tightly sleeved on the middle and upper portion of the tool holder at first; another long plastic sleeve has a part sleeved on the plastic sleeve, and another part sleeved on the tool holder, so as to form a circular step, at a position of 60 to 120mm away from the top of the ball handle.

A magnet is mounted in the ball handle to attract a washer to contact with a ball, and the ball handle and the tool holder perform a relative circular motion. A further preferred structure is: a slotted set screw with a dog point is screwed into a side surface of the ball handle, and the dog point of the slotted set screw abuts against and is slideable in a ring groove on a head of the tool holder, and the ball handle is in slideable engagement with the cylindrical surface of the tool holder along an axial blind hole of the tool holder.

The present invention can make a loosened screw to screw in and out quickly by 360 degree rotation in virtue of the inertia of the linear moment arm, and no finger is required for applying a force to the plastic sleeve of the tool holder. In the case of screwing in or out in a large torque moment, the thumb and the forefinger (the middle finger) can be spread to turn both ends of the moment arm, or the other hand may also be used for force application.

BRIEF DESCRIPTION OF THE DRAWINGS

Further detailed description will be given below to embodiments of the present invention with reference to the accompanying drawings:

FIG. 1 is a sectional view of a preferred embodiment of an inertia moment screwdriver according to the present invention.

FIG. 2 is a perspective view of the preferred embodiment of the inertia moment screwdriver as shown in FIG. 1.

FIG. 3 is a partial sectional view of another embodiment of the inertia moment screwdriver according to the present invention. DETAILED DESCRIPTION OF THE INVENTION

For the convenience of intuitive understanding, a plastic sleeve 9 covering a bolt 6, on the right of a linear moment arm, is omitted in FIGs. 1 and 2, and a screwdriver head 10 is special for a hexagon slotted nut 11. As illustrated in FIG. 1 , the screwdriver head 10 is welded on a tool holder 3; the hexagon bolt 6 adopts M16, and is screwed in a thick nut 7 and pressed against the nut with a bolt head; a connection block 8 is totally screwed in and tightly pressed against a plane of a milled notch of the tool holder 3, the connection block 8 having a dimension equivalent to that of the bolt head, and being made of aluminum or steel; and the plastic sleeve 9 is a heat-shrinkage sleeve.

As known from the preferred embodiments of the present invention as shown in FIGs. 1 and 2, an M4 slotted set screw with a dog point 1 is screwed into a side surface of a ball handle 2. The ball handle 2 may rotate freely and is similar to an instrument screwdriver. A plastic sleeve 5 covers the tool holder 3 at first, and then a longer plastic sleeve 4 covers the tool holder; the plastic sleeve may also be a heat-shrinkage sleeve. As illustrated in FIG. 3 which illustrates another embodiment of the inertia moment screwdriver according to the present invention, a welded screwdriver head 17 is crossed, a tool holder 6 is a straight-bar cylinder, a blind hole is formed on the upper end portion so as to arrange a ball 14, a magnet 12 attracts a washer 13, and a ball handle 15 is made of plastic materials and is clamped on a ring groove of the tool holder 16 by elasticity.

In summary, inertia moment arms in the two embodiments have the same structure. In the case of a small turning torque force, the tool holder 3 is rotated by the fingers; and in the case of a large turning torque force, the linear moment arm is rotated to produce a larger couple. The screws and the nuts applied in the embodiments are standard fasteners. The length and the mass of the bolts 6 can be determined by the experiment according to the maximum torque. The present invention is not limited to the foregoing preferred embodiments. Various deformations and improvements can be made by those skilled in the art without departing from the principle of the present invention and should also fall within the protection scope of the present invention.

Claims

CLAIMS 1. An inertia moment screwdriver, comprising a screwdriver head (10) and a ball handle (2) both fixed on a tool holder (3), characterized in that a linear moment arm in a central portion of the tool holder (3) is formed by a pair of bolts (6) equipped with counterweight nuts (7), the bolts (6) are correspondingly screwed into a connection block (8) to tightly press the tool holder (3), the ball handle (2) positioned by a palm is rotatable with respect to the tool holder (3), plastic sleeves (4) and (5) covering the tool holder (3) are clamped by fingers to rotate and the linear moment arm is also capable of being turned to rotate by the fingers.

2. The inertia moment screwdriver according to claim 1 , characterized in that a screwed hole of the connection block (8) transversely runs through a working position of the screwdriver, a through hole vertically runs through the screwed hole, and the tool holder (3) is tightly fitted with the through hole of the connection block (8).

3. The inertia moment screwdriver according to claim 1 , characterized in that the pair of the bolts (6) are full thread bolts, and after screwed in the nuts (7), the bolts are pressed against the nuts with bolt heads; the connection block (8) is totally screwed in by the tool holder and tightly fixed with the tool holder (3); a plastic sleeve (9) covers a surface of the moment arm.

4. The inertia moment screwdriver according to claim 1, characterized in that the plastic sleeve (5) is tightly sleeved on the tool holder (3), at a position of 60 to 120mm away from the ball handle (2), firstly; and the plastic sleeve (4) has a part sleeved on the plastic sleeve (5) and another part sleeved on the tool holder (3), so as to form a circular step.

5. The inertia moment screwdriver according to claim 1 , characterized in that a slotted set screw with a dog point (1 ) is screwed into a side of the ball handle (2), the dog point of the slotted set screw abuts against a ring groove on a head of the tool holder (3) and is slideable; and an axial blind hole of the ball handle (2) is in slideable engagement with a cylindrical surface of the tool holder (3).