Impact structure for impact power tool

Details Impact structure for impact power tool Impact structure for impact power tool

1999-05-21

2001-05-01

Smith, Scott A. (Department: 3721)

Tool driving or impacting

Impacting devices

With anvil arranged to transmit torsional impact to tool

C173S093000, C173S093600, C173S211000

Reexamination Certificate

active

06223834

ABSTRACT:

BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to an impact structure for an impact power tool, in which an operation body can be rotated by imparting an impact force to the operation body by means of a hammer body.
2. Description of the Related Art
There has been known an impact power tool as a power tool for fastening or unfastening a bolt. In such an impact power tool, an operation body is rotated by intermittently hitting a pawl member of a hammer body, which is rotated by means of a driving actuator such as an electric motor, against a wing member of the operation body in the rotational direction of the hammer body.
The conventional impact power tool has at least two pawl members and at least two wing members, which are disposed at proper positions so as to cause the simultaneous impact contact of the pawl members with the wing members, as described for example in Japanese Utility Model Provisional Publication No. H1-170,570). The impact contacting areas of the pawl member and the wing member are formed into a flat surface so that they are brought into surface contact with each other.
However, in the conventional impact power tool, in which the impact contacting areas of the pawl member and the wing member are formed into the flat surface so that they are brought into surface contact with each other for imparting impact force to the operation body, the transmission of the impact force is conducted through the entirety of the impact contacting area of the pawl member. As a result, the dispersion of force easily occurs due to the flat surface of the pawl member, thus making it impossible to transmit the sufficient driving torque to the operation body. Using a large-sized hammer body can solve the problem. In this case, it is however necessary to make the operation body also in a large size in order to ensure its strength. Accordingly, the product as the impact power tool becomes large and heavy, thus degrading its maneuverability.
It is very hard to cause the simultaneous impact contact of all the pawl and wing members. When there is a small error in production, all the pawl members cannot simultaneously be brought into contact with the corresponding wing members, making a noise.
SUMMARY OF THE INVENTION
An object of the present invention is therefore to provide an impact structure for an impact power tool, which permits to generate sufficient fastening torque without changing the size of the impact power tool and to suppress the occurrence of noise.
In order to attain the aforementioned object, an impact structure for an impact power tool of the present invention comprises:
a hammer body rotatable by means of a driving actuator, said hammer body having at least one pawl member having an impact contacting area; and
an operation body for rotating a bit for the impact power tool, said operation body having at least one wing member having an impact contacting area, which can be brought into contact with said impact contacting area of said pawl member;
said operation body being rotated by intermittently hitting said pawl member of said hammer body against said wing member of said operation body in a rotational direction of said hammer body;
wherein:
said impact contacting area of said pawl member can be brought into point-contact or line-contact with said impact contacting area of said wing member.
The pawl member is preferably hit against the wing member at a position corresponding to radius of gyration of the hammer body.
In addition to the above-mentioned optional, the pawl member is further preferably hit against the wing member at a position corresponding to a node of oscillation mode of the wing member.
At least one of the pawl member and the wing member may comprise a contact piece having the impact contacting area and a base part to which the contact piece is to be fixed, and the contact piece may be detachable from the base part.
At least one of the pawl member and the wing member may have a shock-absorbing member.


REFERENCES:
patent: 3331452 (1967-07-01), Wanner
patent: 3835934 (1974-09-01), Schoeps et al.
patent: 4811797 (1989-03-01), Antipov et al.
patent: 5289885 (1994-03-01), Sakoh
patent: 5544710 (1996-08-01), Groshans et al.
patent: 5706902 (1998-01-01), Eisenhart
patent: 5936403 (1998-11-01), Putney et al.
patent: 5992538 (1999-11-01), Marcengill et al.
patent: 1-170570 U (1989-12-01), None

Affiliated with

Also associated with

Rating

Impact structure for impact power tool does not yet have a rating. At this time, there are no reviews or comments for this patent.

If you have personal experience with Impact structure for impact power tool, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Impact structure for impact power tool will most certainly appreciate the feedback.

Rate now

Comments { 0 }

Profile ID: LFUS-PAI-O-2529545