EP0056106A2 - Safety device for a power-operated nailing device to prevent firing ejection of staples or nails - Google Patents

Abstract

In the unoperated position, a sprung catch protrudes into the ejection channel and is actuated by the work piece by a displaceable actuating element projecting beyond the mouth piece of the nailing device. The catch has an axially fixed, axially acting stop face, which in the unoperated position extends into the ejection channel directly underneath the lower end of the driving pin when the pin is in the upper unoperated position. <IMAGE>

Description

The invention relates to a safety device for power-driven nailers for preventing the projectile ejection of staples or nails, which can be fed from a magazine transversely to the ejection channel, with a driving plunger, a mouthpiece containing the ejection channel and attachable to the workpiece, one on the magazine arranged on the opposite side of the ejection channel resilient lock, which projects into the ejection channel in the rest position, and an actuating element which projects beyond the mouthpiece in the workpiece direction and can be displaced in the opposite direction to the placement direction of the nailer.

So-called trigger safeguards for pneumatic nailers have become known, in which a trigger sensor is provided on the nailer mouthpiece and is mechanically connected to a trigger valve lever or an additional valve via a connecting rod. The trigger sensor protrudes above the nailer's mouthpiece and is moved upwards when it is placed on the workpiece. This enables the trigger sensor to trigger the nailer as long as it is pressed in (US Pat. No. 3,194,324 or US Pat. No. 3,278,106).

The known trigger protection is intended to prevent a shot from being fired before the pneumatic nailer is brought together with the workpiece. However, the trigger lock cannot prevent a shot from firing when the trigger sensor strikes any other object. For example, this can also be the second hand of the operator. Such a touch-down trigger sensor is often used as the actual triggering element during operation, while the actuating lever remains continuously actuated. Finally, the shift linkage and the trigger sensor impair the handiness of the device.

In another known pneumatic nailer, a special triggering sensor and the shift linkage which impairs handling are avoided in that the housing of the pneumatic nailer is mounted so as to be axially displaceable (DE-PS 20 09 455). The trigger valve is only effective when the nailer is on attaches the workpiece and thereby the housing is axially moved against the restoring force of a spring. Although such a construction achieves a relatively high level of security with a simultaneously elegant construction, there is nevertheless the possibility that the operator is able to move the housing without placing it on an object.

It is also known to arrange an additional safety valve in the compressed air path of a nailer, which can be operated manually and prevents triggering in the unactuated state (DE-PS 28 11 339). With the aid of this device, however, it cannot be prevented that a shot is fired even if the touchdown trigger sensor does not touch the workpiece, but rather another object, for example a human hand.

Finally, a safety device without a disturbing linkage to the release valve is known, in which a lock is attached to the nailer on the side of the ejection channel facing away from the magazine, which, when the nailer is at rest, protrudes into the ejection channel in the area of the fasteners supplied to it and the fasteners against Feed force of the feed spring urges out of the discharge channel (DE-PS 19 11 341). The lock consists of an offset leaf spring, the offset of which protrudes into the discharge channel. A ramp-like surface of the offset acts with a deflection Surface of a mouthpiece part together, which thus projects beyond the rest of the mouthpiece in the workpiece direction in the rest position. The slidably arranged movable mouthpiece part is moved upward by placing it on the workpiece, whereby the offset of the leaf spring is moved out of the ejection channel, so that a fastening means can get out of the magazine into the ejection channel in order to be driven in by the driving plunger. If the trigger is actuated without actuating the movable mouthpiece part, the plunger carries out a free shot by simply deflecting the offset to the side.

Despite the simple construction, the last-mentioned safety device has some disadvantages. The exposed mouthpiece can be operated easily or unwanted by the operator. In the case of a free shot, it can happen, despite the lock, that a clip partially protrudes into the discharge channel and is thereby carried along by the driving plunger. This then either results in a projectile-like emergence of a clip from the ejection channel or jamming within the ejection channel. Both phenomena are equally undesirable. Also in the known device it is not prevented that a clip already in the discharge channel is driven out during a free shot.

The invention has for its object a safety device for powered nailers to prevent the projectile To create like escaping staples or nails that is easy to manufacture and assemble and effectively prevents their intended or unintentional decommissioning.

This object is achieved in a safety device mentioned at the outset in that the lock has an axially fixed, axially acting stop surface which, in the rest position, projects directly below the lower end of the driving plunger into the discharge channel in its upper rest position.

While in the safety device described above, the driving plunger performs an empty shot despite the lock, this is prevented in the device according to the invention. The stop surface of the safety device according to the invention is located below and near the lower end of the driving plunger in its upper rest position. If the trigger is now actuated, the plunger pushes against the stop surface from above. This and the storage of the lock as a whole are designed so that the lock is not deflected, but maintains its position. The plunger is therefore held in the upper position despite pressurization of the piston connected to it. At the same time, he exerts a relatively large pressure on the lock, which in this way can then no longer be actuated via the actuating element when it is placed on the workpiece. The safety device according to the invention thus prevents a reverse sequence of actuation of the trigger and actuation element in the mouthpiece. Therefore, a nailer with the safety device according to the invention cannot be used in the manner described above that the trigger is constantly operated by hand and the actual trigger signal is generated by the workpiece sensor.

The advantages achieved with the device according to the invention are, in particular, that it is achieved with certainty that no fastening means can be locked when the trigger valve is actuated unintentionally, as long as the nailer is not effectively placed on the workpiece.

If, in the preceding description and also in the following, reference is often made to pneumatic nailers, the safety device according to the invention is of course not limited to this, but can also be applied to other power-driven nailers, in particular to electronic nailers.

In one embodiment of the invention it is provided that the stop surfaces are formed on a rigid, pivotally mounted locking element which is acted upon by a spring and which cooperates with an axial stop of the mouthpiece. As a result, the blocking element is designed and arranged in such a way that it is able to provide effective resistance to the static pressure of the driving plunger during triggering.

The locking element is between the rest position and the release position pivoted. In this context, a particularly advantageous embodiment of the invention provides that the locking element is pivotally mounted by means of a ball within a mouthpiece part delimiting the ejection channel.

While in the safety device mentioned a mouthpiece part itself is used to actuate the lock, on the other hand, an embodiment of the invention provides that the actuating element is a slide element which is slidably mounted in a guide channel of the mouthpiece. As a result, the actuating element is housed essentially concealed within the mouthpiece and cannot be intentionally rendered ineffective by the operator with simple means.

According to a further embodiment of the invention, the slider element has a lost motion, such that it moves a predetermined distance against the pressure of a spring when it is moved counter to the setting direction of the nailer until it interacts with the locking element. The lock is actuated in two stages in that the actuating element is first shifted counter to the mounting direction against lighter spring pressure and thereby reaches the “pressure point” in such a way that only a further displacement of the actuating element leads to actuation of the lock. In this way, the actuator is almost entirely within of the mouthpiece disappeared and only protrudes a small distance from the mouthpiece. In order to overcome the last path of the actuating element, the spring force to be overcome is expediently greater, so that the operator has to press the nailer against the workpiece with a clear pressure in order to unlock the lock. Unintentional unlocking by the fact that the hedging person. the actuating element touches more or less strongly or touches another object with the nailer is excluded.

The mouthpiece containing the ejection channel is normally formed from two plate-like mouthpiece parts, one of which is usually fixedly connected to the housing or the magazine, while the other is releasably connectable to the first plate, for example by screwing. For this purpose, a further embodiment of the invention provides that the blocking element and the actuating element are concealed in the second mouthpiece part. These parts cannot be operated from the outside.

A particularly simple and effective construction results in a further embodiment of the invention, which is characterized in that two mouthpiece parts have a guide plate delimiting the ejection channel, in which a guide channel for the elongate actuating element is formed on the side opposite the ejection channel is formed fork-shaped in the upper area, the locking element is arranged within the fork leg, a cover plate connectable to the guide plate covers the guide channel and the actuating element and the cover plate in the upper area has a recess for receiving a part of the locking element in its release position. A mouthpiece designed in this way is only imperceptibly larger than conventional mouthpieces and therefore does not constitute a visual obstruction when using the nailer.

According to another embodiment of the invention, the guide plate and cover plate with the received parts form an attachment unit which can be detachably attached to the nailer housing or magazine. The front attachment can be designed in such a way that it can also be attached to nailers that have already been manufactured and are in use in the exchange channels. Typically, the tip plate located on the opposite side of the magazine is attached using screws. The attachment unit can now be provided with screw holes which are aligned with those on the housing or the opposite mouthpiece plate in order to attach the attachment unit.

A particularly preferred embodiment of the invention is described below with reference to drawings.

• Fig. 1 shows a side view and partly in section of a nailer with a safety device the invention.
• Fig. 2 shows a section through the mouthpiece of the nailer of Fig. 1 with the safety device according to the invention.
• Fig. 3 shows the same representation as Fig. 2, but when the safety device is actuated.
• Fig. 4 shows an exploded view of the mouthpiece of the nailer shown in Figures 1 to 3 with the safety device according to the invention.

Before going into the details shown in the drawings, it should be stated that each of the features described and shown is of importance for the invention, either individually or in conjunction with features of the claims.

The nailer shown in Fig. 1 has a housing 1, a magazine 2, a working cylinder 3, in which a working piston 4 with attached driving plunger 5 can be moved up and down, a buffer 6 at the lower end of the cylinder 3 and a release valve 7, which can be actuated by a lever 22, whereby compressed air from the reservoir 23 in the housing 1 can act on the working piston 4 via the compressed air channel 24.

The mouthpiece of the pneumatic nailer is generally designated 9 and contains an ejection channel 8 for the driving plunger 5. The ejection channel 8 is shaped as a groove in a plate-shaped mouthpiece part 30 which is formed in one piece with the housing. The other mouthpiece part is generally designated 31. It is designed as a so-called attachment unit. The structure of the attachment unit is clearly shown in the exploded view according to FIG. 4. It contains a guide plate 10 which, as can be seen in FIGS. 1 to 3, delimits the discharge channel 8 on one side and represents a guide for the driving plunger 5 or the clamp driven by it. On the side of the guide plate 10 facing away from the ejection channel 8, a guide channel 11 is formed in the form of a rectangular groove. The guide plate 10 is provided at the upper end of the guide channel 11 with a rectangular incision 32 which forms an axial stop surface 33. A slide 12 is suitably received in the guide channel 11 and has two parallel-spaced leg sections 25 in the upper region. Below this, the slide 12 is provided with an elongated hole 34. At the lower end it has a bevel 35. The guide channel with received slide 12 is covered by a cover plate 18 which can be screwed to the guide plate with the aid of screws, not shown, which are passed through holes 19. For this purpose, the guide plate has correspondingly aligned screw holes 36.

As can be seen from FIGS. 2 and 3, there is a blocking element 13 arranged between the leg portions 25 of the slide 12. The locking element 13 has on the side facing the cover plate 31 a spherical trough 36, in which a ball 17 is partially received, which is supported by a corresponding ball trough 37 in the facing side of the cover plate 18. The locking element 13 is arranged so that a Lug 21 protrudes into the recess 32 of the guide plate 10 in the upper region and, with the underside 38 of the lug 21, which forms a stop surface, bears more or less against the stop surface 33 when the locking element 13 is in the position shown in FIG. 2 , in which it is pressed into the rest position by a spring 14, which is arranged sunk in an opening of the cover plate 18. The flat side 39 of the blocking element 13 facing the discharge channel 8 lies against the flat bottom of the guide channel 11 in the guide plate 10. The locking element 13 is chamfered at the lower end, as shown at 40, so that it can move partially into a recess 41 in the cover plate 18 when pivoted clockwise according to FIG. 3. As a result, a stop surface 42 on the upper side of the nose 21 and thus this itself is removed from the region of the discharge channel 8, as shown in FIG. 3.

A helical spring 15 is arranged in the elongated hole 34 of the slide 12. Furthermore, a pin 16 extends through a through hole in the cover plate 18 and is inserted into the elongated hole 34. Pin 16 limits the downward movement of the slide 12 when the spring 15 tries to move the slide 12 out of the guide channel 11. As can be seen from FIG. 2, only the bevelled part 35 protrudes out of the guide channel 11 and thus projects beyond the mouthpiece 9 by this amount.

As can be seen from Fig. 4, the Sperrelemnt 13 is provided on both sides of the nose 21 with ramp-like inclined surfaces 26. They are shown in dashed lines in FIGS. 2 and 3. In Fig. 2 it can also be seen that the leg portions 25, which are somewhat rounded at the free end, have a certain distance from the inclined surfaces 26 in the rest position.

Guide plate 10 and cover plate 18 are provided with matching fastening openings 20, via which the attachment unit 31 formed by them can be fastened to the magazine. A corresponding fastening screw 43 can be seen in FIGS. 1 to 3.

The function of the device shown is as follows. In the rest position, the slide 12 is in the extended position under the influence of the compression spring 15. The nose 21 of the locking element 13 projects under the influence of the compression spring 14 into the shock channel 8 of the mouthpiece 9. When the release lever 22 is actuated, compressed air flows from the reservoir 23 into the channel 24 and then into the cylinder, where it is on the end face of the piston 4 acts and generates a downward force thereon. The resulting downward movement of the driving plunger 5 is prevented by the lower end of the driving plunger 5, which ends somewhat above the stop surface 42 in the rest position shown in FIG. 2, being placed on the stop surface 21 and thereby the firing of a clip 27 in the magazine 2 prevented.

The free-shot protection acting in this way is deactivated by placing the mouthpiece 9 on a workpiece, as shown in FIG. 3. The end 35 of the slide 12 projecting from the mouthpiece 9 is pushed up against the restoring force of the compression spring 15. As a result, the leg sections 38 are moved upward in the direction of the inclined surfaces 26. A further upward movement of the slide 12 leads to a pivoting of the locking element 13 in the counterclockwise direction, as in FIG. 3 shown, so that the nose 21 or the axially acting stop surface 42 is removed from the shock channel 8, whereby the way for the driving plunger is free. During this pivoting movement of the locking element 13, it makes a .. movement around the ball 17. After the work process, ie after the device has been lifted off the workpiece, the slide element 12 is pushed again into the rest position (FIG. 2) under the pressure of the spring 15 , so that the leg portions 25 release the inclined surfaces 26 of the lock and this again under the Influence of the compression spring 14 is pivoted back into the rest position.

A deactivation of the free-shot protection with the trigger lever 22 already actuated is prevented by the fact that the driving plunger acts on the stop surface 42 with relatively great pressure and thereby prevents the locking element 13 from pivoting.

Claims (9)

1. Safety device for power-driven nailers for preventing the projectile-like ejection of staples or nails, which can be fed transversely to the ejection channel from a magazine, with a driving plunger, a mouthpiece containing the ejection channel and attachable to the workpiece, one on the side of the ejection channel facing away from the magazine arranged resilient lock, which projects into the ejection channel in the rest position, and an actuating element which projects beyond the mouthpiece in the workpiece direction and can be displaced in the opposite direction to the placement direction of the nailer and which, when placed on the workpiece, actuates the resilient lock so that it releases the ejection channel, characterized in that the lock (13) has an axially fixed, axially acting stop surface (42) which, in the rest position, projects directly into the ejection channel (8) under the lower end of the driving plunger (5) in its upper rest position. 2. Device according to claim 1, characterized in that the stop surface (42) on a spring (14) acted upon rigid, pivotally mounted locking element (13) is formed, which cooperates with an axial stop (33) of the mouthpiece (9) . 3. Apparatus according to claim 2, characterized in that the locking element (13) by means of a ball (17) is pivotally mounted within a mouthpiece part delimiting the discharge channel (8). 4. Device according to one of claims 1 to 3, characterized in that the actuating element is a slide element (12) which is mounted displaceably in a guide channel (11) of the mouthpiece. 5. Apparatus according to claim 2 or 3 and 4, characterized in that the slide element (12) cooperates with a deflecting surface (26) of the locking element (13). 6. Apparatus according to claim 4 or 5, characterized in that the slide element (12) has a lost motion in such a way that it moves a predetermined distance against the pressure of a spring (15) during an adjustment opposite the mounting direction of the nailer until it moves with the Locking element (13) interacts. 7. Device in which the ejection channel is limited by a magazine-side first mouthpiece part connected to the nailer housing and by an opposite second, releasably attachable mouthpiece part, characterized in that the blocking element (13) and actuating element (12) are concealed in the second mouthpiece part (31). are arranged. 8. The device according to claim 7, characterized in that the second mouthpiece part has a guide plate (10) delimiting the ejection channel, in which a guide channel (11) for the elongate actuating element (12) is formed on the side opposite the ejection channel (8), which in turn is fork-shaped (25) in the upper area, the locking element (13) is arranged within the fork legs (25), a cover plate (18) which can be connected to the guide plate (10) covers the guide channel (11) and the actuating element (12) and the cover plate (18) has a recess (41) in the upper region for receiving a part of the locking element (13) in its release position. 9. The device according to claim 8, characterized in that the guide plate (10) and cover plate (18) with the received parts form a releasably attachable attachment unit (31) on the nailer housing or magazine.

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