1. Field of the Invention
The present invention relates to a crack-proof structure of the nail pulling groove of a hammer used in a hammer with a nail pulling groove at rear end thereof. The lower portion of the nail pulling groove of the hammer has a penetrating round hole. A cylindrical rubber plug is inserted in the round hole. Therefore, the nail pulling groove is prevented to crack as the hammer serves to knock a nail or an object.
2. Description of the Prior Art
In the prior art hammer with a nail pulling groove, the distal end of a hammer has a flat shape, and a V shape nail pulling groove is formed therein for forming nail pulling hooks on two sides of the nail pulling groove. Thereby, as a nail is pulled by the hammer, the nail pulling groove can be used to enclose the periphery of the nail, and the hooks will hook the lower rim of the nut portion of the nail. When the handle of the hammer is pulled by the user, the nail will be pulled up so as to separate with the fixing object. Thus, the prior art hammer with a nail pulling groove is convenient in using.
The nail pulling groove is formed by two nail pulling hooks with a V shape. When a user use the hammer to knock a nail or an object, the nail pulling hooks are possibly effected due to a large impact force. Thus, stress is concentrated in the adjacent corners. Namely, the inner stress is concentrated in the bottom of the V shape nail pulling groove. Thus, the bottom of the nail pulling groove is easily cracked due to stress forces. Especially, when the inner stress mixed with the reverse impact force applies to the nail pulling groove, a large impact will induced. Moreover, the function of a hammer to pull a nail is effected, and the lifetime of the hammer is reduced greatly.
USPTO Backgrounds
USPTO Backgrounds