Dual safety combustion powered tool device

A dual safety combustion powered tool device includes a push member disposed to be pressed against a targeted surface to bring a lever to turn to be closer to an actuating unit. A trigger body is pulled to move the actuating unit so as to permit an actuating region to abut against the lever and to turn the actuating unit to an orientation where an actuating region is engageable with an ignition switch. Subsequently, a further movement of the trigger body to a final-stage position permits the actuating region to switch on the ignition switch so as to ignite combustion for initiation of a stroke movement of a driver blade. With such construction, undesired firing of the combustion powered tool device can be avoided.

CROSS-REFERENCE TO RELATED APPLICATION

This application claims priority of Taiwanese Patent Application No. 099126628, filed on Aug. 10, 2010, the disclosure of which is herein incorporated by reference.

BACKGROUND OF THE INVENTION

1. Field of the Invention

This invention relates to a combustion powered tool device, more particularly to a dual safety combustion powered tool device.

2. Description of the Related Art

Referring toFIGS. 1 and 2, a combustion powered tool device1disclosed in U.S. Pat. No. 5,197,646 is shown to include a main housing11for accommodating a piston-driver blade assembly16which strikes a nail fed from a magazine out of a nose end17against a targeted surface when making a stroke movement caused by actuation of a trigger body13. A lock-out pawl14has an end pivotally connected to the trigger body13, and an opposite end. The opposite end is displaced in an aperture151of a valve sleeve member152when the valve sleeve member152is moved to a rearward combustion-chamber closed position, as a result of the engagement of a push member15with the targeted surface. At this stage, as shown inFIG. 2, the trigger body13is permitted to be moved to an actuating position. When the push member15is no longer pressed by the targeted surface and the valve sleeve member152is thereby displaced to a forward combustion-chamber opened position, as shown inFIG. 1, the pawl14is engaged with an external wall of the valve sleeve member152, so that the trigger body13cannot be moved to the actuating position, thereby preventing undesirable firing of the combustion powered tool device1.

However, during operation, if the push member15is not properly engaged with the targeted surface when the trigger body13is moved only halfway to the actuating position, and if the pawl14is displaced to engage the aperture151to permit the trigger body13to freely move, inadvertent continued triggering action by the user toward the actuating position might give rise to an undesirable firing.

SUMMARY OF THE INVENTION

An object of the present invention is to provide a dual safety combustion powered tool device which can prevent undesirable firing thereof.

According to this invention, the dual safety combustion powered tool device includes a housing body defining a main chamber, a handgrip body defining a subchamber adjacent to the main chamber, an ignition switch mounted in and movable relative to the subchamber between a switch-off position and a switch-on position, and a trigger body disposed to be movable among an untriggered position, an initial-stage position, and a final-stage position. An actuating unit is disposed to move with the trigger body, and has a pivot area that defines a pivot axis, an actuated region, and an actuating region opposite to the actuated region relative to the pivot area. The actuating unit is turnable about the pivot axis between a first orientation in which the actuating region is guarded against movement with the trigger body toward the final-stage position so as to leave the ignition switch to remain in the switch-off position, and a second orientation in which the actuating region is engageable with the ignition switch when moving with the trigger body to the final-stage position, thereby displacing the ignition switch to the switch-on position. A first biasing member is disposed to bias the actuating unit toward the first orientation. A push member is disposed forwardly of and movable to a nose end of the housing body to a pressed position as a result of being pressed against a targeted surface. A lever is disposed in the main chamber to be turnable about a fulcrum axis, and has a power end and a weight end which confronts the actuated region, and which is movable between a non-shifted position, where the weight end is remote from the actuated region, and a shifted position, where the weight end is closer to the actuated region. A second biasing member is disposed to bias the weight end toward the non-shifted position. An actuator is disposed forwardly from the power end, and is coupled to move with the push member such that, when the push member is displaced to the pressed position, the actuator is brought to push the power end so as to move the weight end to the shifted position, and such that, when the actuating unit is moved with the trigger body to the final-stage position, the actuated region is brought to abut against the weight end to displace the actuating unit to the second orientation. Therefore, a stroke movement of a driver blade initiated by the ignition switch can not be made without carrying out the steps of pressing the push member against a targeted surface to the pressed position, and pulling the trigger body to the final-stage position in a consecutive manner.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

Before the present invention is described in greater detail, it should be noted that same reference numerals have been used to denote like elements throughout the specification.

Referring toFIGS. 3 and 4, the first embodiment of a dual safety combustion powered tool device2according to the present invention is shown to comprise a housing body20which defines a main chamber201which extends in a longitudinal direction to terminate at nose and head ends202,203. A cylinder21is disposed in the main chamber201, and a piston-driver blade assembly213is disposed in the cylinder21to make a stroke movement so as to strike a nail fed from a magazine5out of the nose end202against a targeted surface. A valve sleeve212is mounted on and movable relative to the cylinder21so as to open and close a combustion chamber211. A push member231is disposed forwardly of and movable to the nose end202between a normal position, where the push member231is remote from the head end203, and a pressed position, where the push member231is closer to the head end203as a result of being pressed against the targeted surface. A biasing member233is disposed to bias the push member231to the normal position. The valve sleeve212is connected to the push member231so as to move therewith. An actuator232is coupled to move with the push member231and extends radially from the valve sleeve212.

A handgrip body6defines a subchamber61adjacent to the main chamber201. An ignition switch22is mounted in and movable relative to the subchamber61between a switch-off position and a switch-on position where the ignition switch22is switched on to ignite a combustion in the combustion chamber211for initiation of the stroke movement of the piston-driver blade assembly213. A trigger body24is disposed to be movable among an untriggered position, an initial-stage position, and a final-stage position.

An actuating unit3is disposed to move with the trigger body24. In this embodiment, the actuating unit3includes a pivot body31, a cam body32, a first biasing member33, and a third biasing member34. The pivot body31has a pivot area pivotally mounted in the subchamber61about a pivot axis310, an actuated region311, and a coupling region312. The cam body32is pivotally mounted in the subchamber61about a cam axis320parallel to the pivot axis310, and which has a cam surface325about the cam axis320to serve as an actuating region322and a non-actuating region323. The actuating region322is distant from the cam axis320by a length that is longer than a length by that the non-actuating region323is distant from the cam axis320. The cam surface325of the cam body32further has a coupled region321which is engaged with the coupling region312of the pivot body31so as to be angularly displaced about the cam axis320as a result of turning the pivot body31about the pivot axis310. In particular, when the pivot body31is turned counterclockwise, the cam body32is brought to turn counterclockwise, and vice versa. Hence, the actuating unit3is turnable between a first orientation in which the actuating region322is guarded against movement with the trigger body24toward the final-stage position so as to leave the ignition switch22to remain in the switch-off position, and a second orientation in which the actuating region322is engageable with the ignition switch22when moving with the trigger body24to the final-stage position, thereby displacing the ignition switch22to the switch-on position. The first biasing member33is disposed on the pivot body31to bias the pivot body31clockwise. The third biasing member34is disposed on and to bias the cam body32to permit the non-actuating region323to confront the ignition switch22. By virtue of the first and third biasing members33,34, the actuating unit3is kept in the first orientation.

A lever41is disposed in the main chamber201to be turnable about a fulcrum axis411, and has a power end413disposed rearwardly of the actuator232, and a weight end412confronting the actuated region311of the pivot body31in the longitudinal direction so as to be movable between a non-shifted position, as shown inFIG. 4, where the weight end412is remote from the actuated region311, and a shifted position, as shown inFIG. 5, where the weight end412is closer to the actuated region311. A second biasing member42is disposed to bias the weight end412toward the non-shifted position. The fulcrum axis411is distant from the power end413by a length that is ½ of a length by that the fulcrum axis411is distant from the weight end412.

Referring toFIGS. 3 and 4, when the combustion powered tool device of this embodiment is in a normal state and is not engaged with a targeted surface, the weight end412of the lever41is in the non-shifted position to be remote from the actuated region311of the pivot body31, and the actuating unit4is in the first orientation, where the non-actuating region323of the cam body32confronts the ignition switch22.

Referring toFIGS. 4 and 5, in use, when the push member231is pressed against the targeted surface to the pressed position, the actuator232is brought to push the power end413of the lever41so as to move the weight end412to the shifted position, where the weight end412is closer to the actuated region311of the pivot body31, thereby placing the combustion powered tool device in a striking ready state. Meanwhile, the valve sleeve212is moved with the push member231to a combustion chamber-closing position so as to close the combustion chamber211.

Referring toFIG. 6, next, when the trigger body24is pressed to the initial-stage position, the actuating unit3is moved with the trigger body24such that the actuated region311of the pivot body31is brought to abut against the weight end412of the lever41to turn the pivot body31counterclockwise. Meanwhile, the cam body32is turned by the pivot body31counterclockwise to displace the actuating unit3to the second orientation, where the actuating region322confronts the ignition switch22.

Referring toFIG. 7, subsequently, when the trigger body24continues to be pressed to the final-stage position, the actuating region322is brought to push the ignition switch22to the switch-on position so as to ignite the combustion for initiation of the stroke movement of the piston-driver blade assembly213for striking a nail into the targeted surface.

Moreover, as shown inFIG. 7, a driving shaft43is disposed in the main chamber201, and is actuated in response to triggering action of the trigger body24to elevate an anchoring end442of a leaf spring44which has an anchored end441connected to the driving shaft43to engage in and urge against the valve sleeve212. Hence, during operation, an undesired premature forward movement of the valve sleeve212can be effectively delayed until when the trigger body24is released and returns to the untriggered position, thereby preventing adverse effect arisen from irregular bouncing-back action of the biasing member233. Meanwhile, as a result of concurrently delayed opening of the combustion chamber211, the driver blade may timely be withdrawn back into the cylinder21.

Referring toFIG. 8, in the event that, before the push member231is pressed against a targeted surface, the user pulls the trigger body24, the ignition switch22can remain in the switch-off position because the actuating unit3is kept in the first orientation. Next, referring toFIG. 9, in the event that while the push member231is pressed against the targeted surface, the counterclockwise turning of the pivot body31and the cam body32is however restrained by the ignition switch22from reaching an extent that is sufficient to move the actuating unit3to the second orientation. Hence, the ignition switch22remains in the switch-off position.

In the event that the push member231is displaced to be disengaged from the targeted surface while the trigger body24has yet be moved toward the final-stage position, i.e., the triggering action has been aborted, as shown inFIG. 6, the weight end412of the lever41is returned to the non-shifted position by the biasing action of the second biasing member42so as to be disengaged from the actuated region311of the pivot body31. Consequently, referring toFIG. 10, the pivot body31and the cam body32are turned clockwise by the biasing action of the first and third biasing members33,34and back to the first orientation. At this juncture, even when the user continues to pull the trigger body24to the final-stage position, as shown inFIG. 11, the ignition switch22remains in the switch-off position. Also, since the length between the fulcrum axis411and the weight end412is longer than the length between the fulcrum axis411and the power end413, the weight end412can be disengaged from the actuated region311of the pivot body31immediately after the power end413is moved forwardly for safety purposes. Subsequent toFIG. 11, and as shown inFIG. 12, once the push member231is pressed against the targeted surface again to turn the pivot and cam bodies31,32counterclockwise, the ignition switch22is engaged in a space between the pivot and cam bodies31,32so as not to be switch on.

Referring toFIG. 13, the second embodiment of a dual safety combustion powered tool device2according to this invention is similar to the first embodiment, except that the actuating unit3is in the form of a single-piece body, and has a pivot area pivotable mounted in the handgrip body6about a pivot axis352, an actuated region350confronting the weight end412of the lever41, an actuating region351, a non-actuating region353, and a pushed region354which are formed on a contour surface thereof and which are angularly displaced from each other about the pivot axis352. The pushed region354is engaged and moved with the trigger body24and is opposite to the actuated region350relative to the pivot axis352. As shown inFIGS. 14 and 15, after the weight end412of the lever91is moved to the shifted position as a result of pressing the push member231against a targeted surface so as to turn the actuating unit3to the second orientation, the actuating unit3can be moved with the trigger body24by pulling the trigger body24to the final-stage position so as to switch on the ignition switch22.

Referring toFIG. 16, once the trigger body24is pulled and the push member231is not pressed against a targeted surface, the actuating unit3is still in the first orientation, where the non-actuating region353confronts and engages the ignition switch22, and the ignition switch22remains in the switch-off position. Hence, undesired firing of the combustion powered tool device2can be avoided.

With such construction of the dual safety combustion powered tool device2according to this invention, uncompleted triggering action of the trigger body24or wrong procedure order of the generation (pulling the trigger body24first, and then pressing the push member231against a targeted surface) cannot result in undesired switching on of the ignition switch22. Therefore, usage of the device2is quite safe.