JPH0647668Y2 - Ignition prevention mechanism for fastener driving tools - Google Patents

Description

[Detailed description of the device]

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a blank driving prevention mechanism for a fastener driving tool having a contact arm assembly as a safety device.

[0002]

2. Description of the Related Art Generally, in a fastener driving tool having a contact arm assembly, a contact portion of the contact arm assembly is located so as to project in the axial direction of the nose from which the fastener is driven. Therefore, the operator of the fastener driving tool, at the time of fastener driving, first presses the contact portion of the contact arm assembly against the fastener driving material to retract the contact portion tip surface to the nose tip surface.
Set the trigger to engage the trigger valve.
As a result, the operator pulls the trigger to open the trigger valve. This opens the head valve that selectively opens and closes the intake passage between the main air chamber that stores compressed air and the striking piston upper chamber of the striking cylinder, allowing compressed air to flow into the striking piston upper chamber at a stroke. , The striking piston rapidly moves toward the upper chamber of the striking piston, the rod-shaped driver integrated with the striking piston rapidly moves toward the tip of the nose, and the fastener supplied in the nose is driven into the fastener driving material. .

In the above fastener driving tool, when the head valve is opened in a state where the fastener is not supplied into the nose, the driver moves due to the rapid movement of the striking piston.
Directly hit the fastener driving material. Therefore, the driver damages the fastener driving material, and at the same time, the impact piston significantly damages the bumper arranged at the bottom of the impact piston lower chamber.

Therefore, a conventional fastener driving tool, for example, a nail driving machine, has, for example, an actual open shaft 52-102988.
No. 56 (Japanese Utility Model Publication No. 57-3726), there is provided a blanking prevention mechanism. According to this idling prevention mechanism, in order to prevent the trigger and the trigger valve from being set to the engageable state due to the movement of the contact arm assembly in a state where the nail is not supplied into the nose, When the number of connected nails is reduced to about three, the stop pin provided on the nose is pushed out by the pusher, thereby fixing the contact arm assembly. However, the actual exploitation 52-102988
According to the idling prevention mechanism of No. 6, the contact arm assembly receives the entire load applied to the contact arm assembly by the stop pin, and the entire load is received by the nose and pusher.
Each of the nose and pusher is loaded to prevent movement of the contact arm assembly. Therefore, the strength of these members, especially the stop pin, must be increased.

[0005]

DISCLOSURE OF THE INVENTION Problems to be Solved by the Invention An object of the present invention is to load a contact arm assembly, a nose and a pusher which prevent movement of the contact arm assembly when a stop pin is not used and a fastener is not loaded in the nose. It is an object of the present invention to provide a blank driving prevention mechanism for a fastener driving tool which does not take up.

[0006]

DISCLOSURE OF THE INVENTION The present invention is directed to a trigger, a magazine having a pusher for pushing a connecting fastener into a nose into which the fastener is driven, and a position and a trigger projecting forward from the tip end surface of the nose in the axial direction of the nose. And a contact arm assembly for retracting the trigger to the operating position by retracting the nose tip surface rearward in the axial direction of the nose by pressing the nose tip surface against the fastener driving material. In the blank driving prevention mechanism, the contact arm assembly is operated by detecting that the number of fasteners in the magazine has decreased to a certain number and rendering the contact arm assembly inoperable. A contact member that can be engaged and disengaged with the trigger, a trigger engagement and disengagement arm member that engages and disengages with the trigger, and both of these. A position that is movable in the axial direction of the nose between the materials and is also movable in the cross section of the nose, and the contact member and the trigger engagement / disengagement arm member are aligned at the same time for engagement, and at the same time with these members. The pusher is characterized in that the pusher has a projection that pushes the relay member out of the aligned position when the number of fasteners in the magazine is reduced to the predetermined number.

[0007]

When the fasteners are used and the number of fasteners in the magazine is reduced to a certain number, the projection of the pusher pushes the relay member to disengage it from the aligned position as the pusher approaches the nose. Therefore, even if the contact member moves in the axial direction of the nose, the trigger engagement / disengagement arm member does not move. As a result, blank driving is prevented.

[0008]

According to the present invention, when the number of fasteners in the magazine is reduced to a certain number, the connection between the contact member and the trigger engagement / disengagement arm member is cut by the relay member, so that the fastener driving member contacts the fastener member. The load due to being pressed is not applied to other members. Therefore, the durability of the blank-driving prevention mechanism and related members is improved.

[0009]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT A preferred embodiment of the present invention will be described below with reference to FIGS. A nailing machine using compressed air as a power source has a nailing machine body 1 incorporating a striking cylinder / piston mechanism. The nailing machine main body 1 includes a housing portion 2 having a striking cylinder / piston mechanism for starting a nailing stroke by pulling a trigger 1a, and a grip portion protruding from the housing portion 2 in the lateral axis direction of the housing portion 2. 3 and 3. A nose 4 is provided at the tip of the housing 2 so as to be coaxial with the striking cylinder / piston mechanism. The nose 4 has a magazine 5 and a pusher 6 inside.
Accepts the connecting nails 14 sent by one by one.
A rod-shaped driver integrated with the striking piston of the striking cylinder / piston mechanism drives the nail supplied into the nose 4 into the nail driving material. A contact arm assembly 7 as a safety device extends between the tip of the nose 4 and the trigger 1a.

As shown in FIG. 1, the contact arm assembly 7 is mounted on the tip of the nose 4 so as to be movable in the axial direction of the nose 4.
And a relay member 9 which is movable in the longitudinal direction of the nose 4 and is pivotally movable within the cross section of the nose 4 on the side surface of the magazine 5 and which is detachable from the contact member 8 and the relay member 9. 9 and a trigger 1a, the trigger engaging / disengaging arm member 10 extends in the axial direction of the housing portion 2 and is movable in the axial direction of the housing portion 2.

The contact member 8 has a tip surface 8a when the tip surface 4a of the nose 4 is not pressed against the nail driving material.
It is biased by a spring (not shown) so that a is located at a position projecting from the tip surface 4a of the nose 4 in the axial direction of the nose 4. The tip end surface 8a of the contact member 8 is retracted to the tip end surface 4a of the nose 4 by being pressed against the nail driving material, and the relay member side projection 8b of the contact member 8 is pressed against the nose side projection 9a of the relay member 9. The relay member 9 is shifted toward the trigger 1a. The relay member 9
Is provided with the nose-side protrusion 9a and the trigger-side protrusion 9b which project in opposite directions at both axial ends. The central shaft 9c of the relay member 9 is integral with the relay member 9 and is shiftable in the longitudinal direction of the nose 4 and rotatable within the cross section of the nose 4. As shown in FIGS. 2 and 3, a pusher-side protrusion 9d projects from the relay member 9 into the magazine 5 through an opening 11 provided in the magazine 5. The trigger engagement / disengagement arm member 10 has a nose side projection 9a of the relay member 9 and a relay member side projection 10a that can be engaged / disengaged.

A pusher 6 for pushing the connecting nail 14 toward the nose 4 is arranged in the magazine 5. The pusher 6 is biased to move toward the nose 4 by a helical spring (not shown). A plate-shaped push plate 12 is provided on the front portion of the pusher 6. The front end portion 12a of the push plate 12 contacts the nail 14a at the rear end position of the connecting nail 14. A protrusion 13 for rotating the relay member 9 is provided on one side surface (the lower side surface in FIG. 1) of the push plate 12. As shown in FIG. 3, when the consumption of the connecting nail 14 progresses and the number of the remaining nails becomes three, the protrusion 13 causes the pusher 6 to approach the nose 4 so that the protrusion 9d of the pusher side of the relay member 9 is pushed. Rotate. As a result, the relay member 9 rotates, and the alignment between the nose side protrusion 9a and the relay member side protrusion 8b of the contact portion 8 is released. As a result, even when the contact portion 8 is pressed against the nail driving material and the tip end surface 8a of the contact portion 8 is flush with the tip end surface of the nose 4, the relay member 9 and the trigger engaging / disengaging arm member 10 are noseed. The trigger engagement / disengagement arm member 10 does not move in the axial direction of 4 toward the trigger 1a.
The trigger 1a is not set to the engageable position.

In the above embodiment, the relay member is displaced from the simultaneous alignment position of the contact member and the trigger engagement / disengagement arm by rotation, but is displaced from the alignment position by the linear movement of the nose in the horizontal axis direction. Good.

[Brief description of drawings]

FIG. 1 is a schematic side view of a nailing machine having a blank driving prevention mechanism according to the present invention.

2 is a cross-sectional view taken along the line II-II of FIG. 1, showing a state in which the idle driving prevention mechanism is not operating.

3 is a cross-sectional view taken along the line II-II of FIG. 1, showing a state in which the idle driving prevention mechanism is activated.

[Explanation of symbols]

 1a Trigger 4 Nose 4a Nose tip part 5 Magazine 6 Pusher 7 Connecting fastener 8 Contact member 9 Relay member 10 Trigger engagement / disengagement arm member 13 Protrusion

Claims (1)

[Scope of utility model registration request] 1. A magazine provided with a trigger, a pusher for pushing a connecting fastener into a nose into which the fastener is driven, and a magazine disposed between a position projecting forward from a tip end surface of the nose in the axial direction of the nose and a position of the trigger. A blank driving prevention mechanism provided in a fastener driving tool having a contact arm assembly for retracting the trigger in the axial direction of the nose by retracting the tip end surface of the nose into the axial direction of the nose and setting the trigger to the operating position. In a blanking prevention mechanism that operates by detecting that the number of fasteners in the magazine has decreased to a certain number and makes the contact arm assembly inoperable, the contact arm assembly is composed of a fastener driving material and a detachable contact member. , The trigger engagement / disengagement arm member that engages / disengages with the trigger, and the axial direction of the nose between these members. The contact member and the trigger engagement / disengagement arm member are aligned at the same time for engaging the contact member and the trigger engagement / disengagement arm member, and a position out of the simultaneous alignment of these members. The pusher has a protrusion that pushes the relay member out of the aligned position when the number of fasteners in the magazine is reduced to the predetermined number. .