EP3446833B1 - Pneumatic nail gun with safety valve assembly - Google Patents

Description

The invention relates to a pneumatic nailer, which has a trigger, a touch sensor and a control valve arrangement. If the compressed air rodent is attached to a workpiece, the surface-mounted sensor is displaced against the force of the spring until an orifice tool lies against the workpiece or almost touches it. A drive-in process can only be triggered when the touch-down sensor is activated in this way. As a result, the pneumatic nailers offer considerably improved security against unintentional triggering compared to devices without a touch sensor.

Some pneumatic nailers of the type described can be used in two different operating modes: With the so-called single triggering, the pneumatic nailer is first attached to a workpiece and the attachment sensor is thereby actuated. The trigger is then actuated by hand, triggering a single drive-in process. With the so-called contact release, also referred to as "touching", the user already keeps the trigger pressed while he attaches the pneumatic nailer to the workpiece. When attaching to the workpiece, the touch-down sensor is actuated, triggering a driving-in process. The pneumatic nailer can be used repeatedly in quick succession, which enables very fast work, especially if many fasteners have to be driven in for adequate fastening, and the positioning accuracy of which is only low.

In certain situations, however, the contact initiation process poses an increased risk of injury. For example, the user keeps the manual trigger pressed not only when he wants to place the pneumatic nailer on the same workpiece at a distance of a few centimeters from the last fastener driven in, but also when he changes to another, remotely located workpiece if the object touches an object or part of the body unintentionally, a driving-in process to be triggered. For example, accidents can occur if a user (ignoring important safety regulations) climbs onto a ladder with the pneumatic nailer, keeps the trigger pressed and accidentally brushes his leg with the touch probe.

Some known pneumatic nailers seek to reduce this risk associated with the contact release operation by the fact that contact release is only possible for a short period after the trigger has been actuated or after a driving-in operation. Once the period has elapsed, the trigger must first be released. An example of this is from the publication EP 2 767 365 B1 known. The pneumatic nailer described therein has a trigger and a touch-down sensor, each of which is assigned a control valve. In addition, the known device has a safety control chamber, the pressure of which acts on a locking piston. In a certain position of the locking piston, the triggering of a driving-in process is prevented. The safety control chamber is ventilated via the control valve assigned to the trigger and a throttle. As a result, after the trigger has been actuated, contact release is only possible until the pressure in the safety control chamber has exceeded a predetermined pressure threshold. The pneumatic nailer is then blocked until the trigger is released and the pressure in the safety control chamber has dropped below the pressure threshold again.

A similar functionality is offered by the U.S. Patent No. 3,964,659 Pneumatic nailer that has become known, which can also be used in a single and in a contact release mode and in which a trigger and a touch-down sensor are mechanically coupled via a rocker. The rocker acts on a control valve in order to trigger a drive-in process by venting a main control line. If only the trigger and not the touch sensor is actuated, a control pin of the control valve is only displaced over part of its adjustment path. This half actuation of the control valve leads to a slow ventilation of a control chamber through a small ventilation opening. The pressure prevailing in the control chamber acts on a valve sleeve that surrounds the control valve and finally shifts this valve sleeve into a blocking position in which a complete actuation of the valve pin can no longer vent the main control line, so that a contact triggering is not possible.

A further improvement in safety can be achieved if a first driving-in process always has to be carried out by individual triggering. In this case, the device must first be attached to the workpiece for the first driving-in process, whereby the touch-down sensor is actuated. Subsequent actuation of the trigger then triggers the first driving-in process. Subsequently, further driving operations can be carried out by triggering the contact within a short period of time, i.e. by repeatedly lifting and attaching the device to the workpiece while the trigger is continuously pressed. This functionality is the same as in the publication DE 10 2013 106 657 A1 pneumatic nailer described. For this purpose, a trigger and a touch-down sensor are mechanically coupled via a rocker, which acts on a control valve in order to trigger a driving-in process. With each driving process, a pressure is built up in a control chamber, which acts on a mechanical actuator. The control chamber is slowly vented through a vent. Depending on the pressure in the control chamber, the actuator moves into a blocking position, which prevents the touch sensor from acting mechanically on the rocker when the trigger is actuated, making contact tripping impossible. Other examples are also out US 7,556,183 B1 and US 2017/209995 A1 known.

Based on this, it is the object of the invention to provide a pneumatic nailer with an effective, robust and reliable safety mechanism.

This object is achieved by the pneumatic nailer with the features of claim 1. Advantageous refinements are specified in the subsequent subclaims.

• einen Arbeitskolben, der mit einem Eintreibstößel zum Eintreiben eines Befestigungsmittels verbunden ist und beim Auslösen eines Eintreibvorgangs mit Druckluft beaufschlagt wird,
• einen Auslöser und einen Aufsetzfühler, deren gemeinsame Betätigung eine Hauptsteuerleitung be- oder entlüften und dadurch einen Eintreibvorgang auslösen kann,
• eine Steuerventilanordnung, die ein dem Auslöser zugeordnetes Auslöserventil und ein dem Aufsetzfühler zugeordnetes Aufsetzfühlerventil aufweist, und
• eine Sicherheitsventilanordnung, die durch Steuern des Drucks in einem ersten Steuerraum und des Drucks in einem zweiten Steuerraum zwischen einer Sperrstellung und einer Offenstellung verlagerbar ist, wobei
• die Hauptsteuerleitung in der Offenstellung mit der Steuerventilanordnung verbunden und in der Sperrstellung nicht mit der Steuerventilanordnung verbunden ist,
• der erste Steuerraum derart mit dem Auslöserventil verbunden ist, dass eine Betätigung des Auslöserventils die Sicherheitsventilanordnung in die Sperrstellung zu bringen sucht, und
• in der Offenstellung der zweite Steuerraum derart mit dem Aufsetzfühlerventil verbunden ist, dass eine Betätigung des Aufsetzfühlerventils die Sicherheitsventilanordnung jedenfalls bei betätigtem Auslöserventil in die Offenstellung zu bringen sucht.

The pneumatic nailer has

• a working piston which is connected to a driving plunger for driving in a fastening means and which is acted upon by compressed air when a driving-in process is triggered,
• a trigger and a touch-down sensor, the joint actuation of which can vent a main control line and thereby trigger a driving process,
• a control valve arrangement which has a trigger valve assigned to the trigger and a touch sensor valve assigned to the touchdown sensor, and
• a safety valve arrangement which can be shifted between a blocking position and an open position by controlling the pressure in a first control chamber and the pressure in a second control chamber, wherein
• the main control line is connected to the control valve arrangement in the open position and is not connected to the control valve arrangement in the blocking position,
• the first control chamber is connected to the trigger valve such that actuation of the trigger valve attempts to bring the safety valve arrangement into the blocking position, and
• in the open position the second control chamber is connected to the touch-down sensor valve such that actuation of the touch-down sensor valve tries to bring the safety valve arrangement into the open position in any case when the trigger valve is actuated.

The pneumatic rodent is used to drive in fasteners such as nails, pins or staples. For this purpose, the pneumatic nailer can have a magazine for the fastening means, from each of which a fastening means is fed to a receptacle of a mouth tool of the pneumatic nailer. When a driving-in process is triggered, compressed air is applied to a working piston of the pneumatic nailer. The working piston drives a driving plunger, which is connected to the working piston. The driving plunger strikes a rear end of the fastening means in the receptacle of the mouth tool and drives the fastening means into the workpiece.

The touch-down sensor can be a mechanical component which projects beyond the front end of the mouth tool and is held in this position by a spring until the pneumatic nailer is attached to a workpiece. Then the touch sensor is moved against the direction of the spring force and against the driving direction until a muzzle tool of the pneumatic nailer bears against the workpiece or almost bears against it.

The pneumatic nailer has a main control line, which is aerated or vented to trigger a driving process. In order to enable this ventilation of the main control line, the main control line is connected to the control valve arrangement in the open position of the safety valve arrangement. The driving process can be initiated in different ways by means of the main control line. For example, an embodiment with a main valve and a pilot valve, which is controlled via the main control line, is known. Details of this are explained for the exemplary embodiment. However, other constructions with or without pilot valve are also conceivable. It is only important for the invention that the driving-in process can be triggered by venting or venting the main control line.

The control valve arrangement comprises two valves, each of which is assigned a mechanical actuating element. These are the trigger valve, which is actuated by the trigger to be actuated by hand, and the touchdown sensor valve, which is actuated or can be actuated by the touchdown sensor, that is to say when the pneumatic nailer is attached to a workpiece.

A special feature of the invention is the safety valve arrangement. It is a pressure-controlled valve arrangement with two control rooms. The pressures in the two control rooms act on the safety valve arrangement or on at least one displaceable actuator of the safety valve arrangement, so that the safety valve arrangement can be shifted between a blocking position and an open position by controlling these pressures.

The safety valve assembly performs two important functions. First, it controls whether the main control line is connected to the control valve assembly. Only if this is the case can a driving-in process be triggered by means of the control valve arrangement. The safety valve arrangement thus prevents a driving-in process from being triggered if it is in the blocking position.

On the other hand, the position of the safety valve arrangement is decisive for whether or not there is a connection between the touch-down sensor valve and the second control chamber. This connection exists in the open position, so that actuation of the touch-down sensor valve can influence the pressure in the second control chamber. If, on the other hand, the safety valve arrangement is in the blocking position, the connection mentioned does not exist and actuation of the touch-down sensor valve has no significant influence on the pressure in the second control chamber.

The first control chamber is connected to the trigger valve in such a way that actuation of the trigger valve attempts to bring the safety valve arrangement into the blocking position. This means that the connection between the trigger valve and a force is exerted on the first control chamber on a displaceable element of the safety valve arrangement in the direction of the blocking position. Depending on the design, this can be achieved by venting the first control room, but also, for example, by venting the first control room. The connection between the trigger valve and the first control chamber can exist regardless of the position of the safety valve arrangement.

This solution means that starting from an initial state of the pneumatic nailer, a driving-in process can only be triggered in a certain order by actuating the touch-down sensor and the trigger. If the trigger is actuated first, the connection of the trigger valve to the first control chamber causes the safety valve arrangement to be shifted into the blocking position. Subsequent actuation of the touch-down sensor and the associated touch-down sensor valve can then no longer act on the second control chamber, so that the safety valve arrangement remains in the blocking position and no driving-in process is triggered. If, on the other hand, the touch-down sensor is actuated first while the safety valve arrangement is in its open position, the pressure in the second control chamber can be influenced in such a way that the safety valve arrangement remains in its open position when the trigger and thus the trigger valve are subsequently actuated. For this purpose, the two control rooms of the safety valve arrangement are to be designed such that the forces exerted on the safety valve arrangement by the pressures in the two control rooms, possibly including other forces acting on the safety valve arrangement, hold the safety valve arrangement in the open position or shift it to the open position.

As long as the pneumatic nailer is in a basic state, for example after starting up the pneumatic nailer (e.g. by connecting the pneumatic nailer to a compressed air source) or after a break from work, it is fundamentally not possible to initiate a driving process by first triggering and then when the trigger is actuated , the touch probe is operated.

The described influencing of the pressure in the second control chamber by actuating the touch-down sensor valve occurs at any rate when the trigger is actuated. The control valve arrangement can optionally also be designed so that the action of the touch-down sensor valve on the second control chamber occurs regardless of the state of the trigger valve. However, this is not necessary for the function described.

When the surface-mounted sensor valve is actuated in the open position, the second control chamber is connected to the surface-mounted sensor valve in such a way that an actuation of the surface-mounted sensor valve always tries to bring the safety valve arrangement into the open position when the trigger valve is actuated. This means that actuation of the touch-down sensor valve influences the pressure in the second control chamber in such a way that a force is exerted on a movable element of the safety valve arrangement in the direction of the open position. This happens at least when the trigger valve is actuated at the same time. The action of the touch-down sensor valve on the second control room can consist in ventilation of the second control room, but depending on the design of the safety valve arrangement, venting of the second control room can also be considered when the touch-up sensor valve is actuated, for example.

In one embodiment, the safety valve arrangement has a single actuator which can be shifted between the blocking position and the open position, a pressure in the first control chamber having a first force on the actuator and a pressure in the second control chamber having a second force opposite to the first force the actuator exercises. As explained, the safety valve arrangement is responsible for establishing or separating two connections, namely on the one hand between the main control line and the release valve and on the other hand between the surface-mounted sensor valve and the second control chamber. These functions can basically be performed with the help of separate actuators. The use of a single actuator is in contrast, it is particularly simple. In particular, the two control spaces can be arranged on opposite sides of the actuator, so that the forces exerted on the actuator by the respective pressures are automatically directed in opposite directions. The effects of the two forces can be measured by a suitable choice of the surfaces of the actuator on which the pressures act, in particular in such a way that the actuator remains in the open position when both forces act simultaneously.

In one configuration, the pneumatic nailer has a spring which exerts a force on the actuator in the direction of the open position. It can thereby be achieved that in the initial state of the pneumatic nailer the actuator is in a defined position, namely in the open position.

In one embodiment, each actuation of the trigger valve causes the first control chamber to be ventilated. For this purpose, an input of the trigger valve can be connected to a housing interior carrying compressed air, and an output of the trigger valve can be in constant communication with the first control chamber via a line. As a result, the safety valve arrangement always comes into the blocking position each time the trigger is actuated, provided that the pressure in the second control chamber does not lead to sufficiently large, oppositely directed forces.

In one embodiment, the trigger valve is actuated each time the trigger is actuated, regardless of a position of the touch sensor. The trigger thus acts directly on the trigger valve, in particular in that a contact surface of the trigger acts on a valve pin of the trigger valve. A complex and possibly error-prone mechanical coupling between the trigger and the surface sensor, for example via a rocker, is not required.

In one embodiment, the touchdown sensor valve is actuated each time the touchdown sensor is actuated, regardless of a position of the trigger. Works here too So the touch sensor directly onto the touch sensor valve, for example with an actuating surface of the touch sensor, which acts on a valve pin of the touch sensor valve. Here, too, there is no need for a complex and possibly error-prone mechanical coupling between the trigger and the contact sensor.

In one configuration, the main control line is connected in the open position to an output of the touch-down sensor valve and an input of the touch-down sensor valve is connected to an output of the trigger valve. The trigger valve and touch-down sensor valve are therefore connected in series, so that both of the valves mentioned must be actuated to influence the pressure in the main control line. This applies in particular to a ventilation of the main control line, for which it is provided to connect an inlet of the trigger valve with a housing interior carrying compressed air. In this case, the compressed air is fed from this housing interior via the trigger valve and the touch-down sensor valve into the main control line if the two valves are actuated at the same time. As a result, in a particularly simple manner and without additional mechanical coupling elements, a driving-in process can basically only be triggered if the two valves are actuated at the same time.

In one embodiment, a non-return valve is arranged in a line that connects the touch-down sensor valve to the second control chamber in the open position. The check valve can be aligned in such a way that with the aid of the surface-mounted sensor valve, only ventilation or exclusively ventilation of the second control room is possible. In both cases, the check valve can result in the pressure prevailing in the second control chamber being maintained regardless of the position of the touch-down sensor valve.

In one configuration, the second control chamber is vented via a throttle and connected to a storage chamber. The volume of the storage chamber and the opening cross-section the throttle can be selected so that the pressure conditions established with the aid of the touch-down sensor valve in the second control chamber are maintained for a period of, for example, 0.5 seconds to 10 seconds to such an extent that the safety valve arrangement remains in the open position. It is then possible to initiate contact within this period.

In one configuration, the safety valve arrangement vents the second control chamber in the blocking position. As a result, the pressure in the second control chamber can be reset each time the safety valve arrangement responds, that is to say whenever the safety valve arrangement comes into the blocking position. This means that the safety valve arrangement remains reliably in the blocking position, at least as long as the pressure conditions in the first control chamber do not change.

In one configuration, the safety valve arrangement vents the main control line in the blocking position. This security measure counteracts an unintentional triggering of a driving process.

In one configuration, the safety valve arrangement has a locking sleeve as an actuator, within which the touch-down sensor valve is arranged. This constructive measure enables a particularly compact structure to be achieved.

In one embodiment, the surface-mounted sensor valve has a fixed valve sleeve and a displaceable valve pin guided therein, the locking sleeve surrounding the valve sleeve and interacting with it. This measure also favors a compact structure.

Fig. 1

einen Druckluftnagler in einer teilweise geschnittenen Darstellung,

Fig. 2

eine vergrößerte Ansicht eines Ausschnitts mit Hauptventil und Vorsteuerventil aus Figur 1,

Fig. 3

einen Pneumatik-Schaltplan der Steuer- und Sicherheitsventilanordnung des Druckluftnaglers aus Fig. 1,

Fign. 4 bis 9

vergrößerte Darstellungen der Steuer- und Sicherheitsventilanordnung des Druckluftnaglers aus Fig. 1 in unterschiedlichen Betriebszuständen.

In one configuration, the check valve is formed by an O-ring which is inserted into a circumferential groove in the valve sleeve. Such a check valve can be used in the smallest space between the blocking sleeve and the valve sleeve. The invention is explained in more detail below on the basis of an exemplary embodiment shown in the figures. Show it:

Fig. 1

a pneumatic nailer in a partially sectioned illustration,

Fig. 2

an enlarged view of a section with the main valve and pilot valve from Figure 1 ,

Fig. 3

a pneumatic circuit diagram of the control and safety valve arrangement of the pneumatic nailer Fig. 1 ,

Fig. 4 to 9

enlarged representations of the control and safety valve arrangement of the pneumatic nailer Fig. 1 in different operating states.

First, the Fig. 1 an overview of the structure of a pneumatic nailer 10 according to the invention given. The pneumatic nailer 10 has a lower housing part 140 with a handle 12. The lower housing part 140 is closed at the top by a housing cap 142.

A control valve arrangement is arranged on the handle 12 with a trigger valve 22, which is assigned to a trigger 14, and a touchdown sensor valve 18, which is assigned to a touchdown sensor 24. The touch-down sensor 24 projects a few millimeters downward over the mouth 26 of a mouth tool 28. If the pneumatic nailer 10 is attached to a workpiece, the placement sensor 24 is displaced upward against the force of a spring, not shown, until it is flush or almost flush with the mouth 26. A slider 30, which is a continuation of the touchdown sensor 24 or is connected to the touchdown sensor 24, always moves together with the touchdown sensor 24. In particular, it follows its movement upwards relative to the housing when the pneumatic nailer 10 is attached to a workpiece until he actuated the touch sensor valve 18.

The mouth tool 28 has a receptacle 46, to each of which a fastener is fed from a magazine 48. From this position within the receptacle 46, the fastening means - for example a nail, a pin or a clamp - is driven in by a driving plunger 50 which is connected to a working piston 52 of the pneumatic nailer 10. For this purpose, the working piston 52 is guided in a working cylinder 54. A main valve 56 is arranged above the working cylinder 54 and closes it in a sealing manner, to the right of it a pilot valve 58 which controls the main valve 56. Details of these elements as well as the related function are shown on the basis of the enlargement of the Figure 2 explained.

In the Figure 2 are individual elements of the pneumatic nailer 10, which in Fig. 1 are arranged above the housing cap 142, omitted. The pilot valve 58 is clearly visible. It has a control piston 94 which is guided in a guide sleeve 96. The lower end of the control piston 94 is sealed with a lower O-ring 100 with respect to the guide sleeve 96. In the initial state of the pneumatic nailer 10, a main control line 82, which is connected to a working volume of the pilot valve 58, is vented and the control piston 94 is in the lower position shown. In this position, it is held by the force of a spring 102.

The control piston 94 has, in addition to the lower O-ring 100, a central O-ring 104 and an upper O-ring 106. In the lower position of the control piston 94 shown, the upper O-ring 106 seals the control piston 94 against the guide sleeve 96 and closes a connection to a ventilation opening 108 which is connected to outside air. The middle O-ring 104 is not in seal, so that a control line 110 is connected to the housing interior 64 via a radial bore 112 in the guide sleeve 96 and the annular gap 70 between the control piston 94 and guide sleeve 96 past the middle O-ring 104. The control line 110 is not visible over a section plane shown in the figure Connection with the space 72, which opens into the radial bore 112 connected. In the initial state of the pneumatic nailer 10, the housing interior 64 is ventilated, ie connected to a compressed air connection, not shown, and is under operating pressure.

The control line 110 is connected to a space 114 above a main valve actuator 116 of the main valve 56, so that the main valve actuator 116 is subjected to a downward force and seals the upper edge of the working cylinder 54 against the housing interior 64 by means of an O-ring 118 . In addition, the main valve actuator 116 is acted upon by a spring 120 with a force in the direction of the position shown, which closes the working cylinder 54.

A drive-in process is triggered by venting the main control line 82 by moving the control piston 94 upward, so that the middle O-ring 104 comes into seal and the upper O-ring 106 moves out of the seal. As a result, the connection of the control line 110 to the housing interior 64 is blocked and a connection is established between the control line 110 and a ventilation opening, not shown. The space 114 above the main valve actuator 116 is vented via the ventilation opening and the main valve actuator 116 is displaced upward against the force of the spring 120 by the pressure prevailing on its lower, outer annular surface 122 in the housing interior 64. As a result, compressed air flows from the housing interior 64 into the working cylinder 54 above the working piston 52 and drives the working piston 52 downward. During this downward movement, the driving plunger 50 connected to the working piston 52 drives in a fastening means.

The interaction of the control valve arrangement with the safety valve arrangement is first of all based on the pneumatic circuit diagram of the Figure 3 explained. This shows the main control line 82 in the upper left, which in the exemplary embodiment relates to the Pilot valve 58 leads. To the right of this is the safety valve arrangement 16 in a dotted rectangle. The rectangle, also shown further dotted on the right, combines the touch-down sensor valve 18 and the trigger valve 22 to form the control valve arrangement 20.

The trigger valve 22 actuated by the trigger 14 has a first inlet 32 which is connected to the housing interior 64. A second inlet 34 of the trigger valve 22 is connected to outside air. The output 36 of the trigger valve 22, which is connected to the second input 34 in the drawn, unactuated position of the trigger valve 22, is connected via a line 38 to a first input 40 of the touchdown sensor valve 18. The second inlet 42 of the touch-down sensor valve 18 is connected to outside air. In the illustrated, unactuated position of the surface-mounted sensor valve 18, the outlet 44 of the surface-mounted sensor valve 18 is connected to the second input 42 of the surface-mounted sensor valve 18.

The safety valve arrangement 16 has a first control chamber 60, a second control chamber 62, a first outlet 66 and a second outlet 68. In addition, the safety valve arrangement 16 has a first inlet 74, a second inlet 76, a third inlet 78 and a fourth inlet 80 only actuator 98 of the safety valve arrangement 16 can be shifted from the open position shown into a blocking position.

The first inlet 74 of the safety valve arrangement 16 is connected via a line 124 to the outlet 44 of the surface-mounted sensor valve 18. The first outlet 66 of the safety valve arrangement 16 is connected to the main control line 82, the second inlet 76 of the safety valve arrangement 16 is connected to outside air. In the drawn open position of the safety valve arrangement, the first input 74 is connected to the first output 66, so that there is a connection between the main control line 82 and the control valve arrangement 20.

The third input 78 of the safety valve arrangement 16 is connected via a line 126, in which a check valve 128 is arranged, to the output 44 of the touchdown sensor valve 18. The fourth input 80 of the safety valve arrangement 16 is connected to outside air. The second outlet 68 of the safety valve arrangement 16 is connected to a storage chamber 130 and to the second control chamber 62. There is also a connection between the second control chamber 62 or the second outlet 68 of the safety valve arrangement and a throttle 132, via which the storage chamber 130 is vented. In the open position of the safety valve arrangement 16 shown, the third inlet 78 is connected to the second outlet 68, so that ventilation of the second control chamber 62 is possible via the touch-down sensor valve 18.

The first control chamber 60 is connected to the outlet 36 of the trigger valve 22 via a line shown in broken lines.

Based on the basic state of the Figure 3 First actuated the trigger valve 22, its output 36 is connected to the housing interior 64. As a result, the first control chamber 60 is ventilated, as a result of which the actuator 98 of the safety valve arrangement 16 is shifted into the blocking position. As a result, the connection between the third input 78 and the second output 68 of the safety valve arrangement is interrupted, so that subsequent actuation of the touch-down sensor valve 18 cannot vent the second control chamber 62. In addition, the first output 66 is separated from the first input 74 of the safety valve arrangement 16, so that the control valve arrangement 20 no longer act on the main control line 82 and a driving-in process cannot be triggered.

As an additional safety measure, the main control line 82 is vented through the connection between the first outlet 66 and the second inlet 76 of the safety valve arrangement 16 which is established in the locked position. If a pressure different from outside air prevailed in the storage chamber 130, this becomes vented at the same time via the connection established by the safety valve arrangement 16 between the second outlet 68 and the fourth inlet 80.

The triggering of a driving-in process is only possible again when the trigger valve 22 is brought into its unactuated position by releasing the trigger 14. At this moment, the first control chamber 60 is in fact vented via the connection established between the outlet 36 and the second inlet 34 of the trigger valve 22, so that the actuator 98 returns to its open position by the force of the spring 84.

In order to trigger a first driving-in process starting from the initial state, the touch-down sensor valve 18 must first be actuated. This creates a connection between the first input 40 and the output 44 of the touch-down sensor valve 18. With a subsequent actuation of the trigger valve 22, a connection is then established between its first input 32 and its output 36, so that compressed air via line 38 into the first control chamber 60 and at the same time via the actuated touch-up sensor valve 18, the check valve 128 and the line 126 and the in the open position existing connection between the third input 78 and the second output 68 of the safety valve arrangement 16 flows into the second control chamber 62. The forces acting through the pressures in these two control spaces thus act simultaneously on the actuator 98, which in cooperation with the spring 84 leads to the actuator 98 remaining in the open position shown. Therefore, the ventilation of the line 124 also causes the main control line 82 to be ventilated and a driving-in process is triggered.

If the device is removed from the workpiece after this driving-in process, the touch-down sensor valve 18 returns to its drawn, unactuated position. Because of the check valve 128, the pressure prevailing in the storage chamber 130 and the second control chamber 62 is initially maintained, so that the actuator 98 remains in its open position. However, the pressure in the second control chamber 62 and the storage chamber 130 slowly decreases via the throttle 132 until it finally drops below a pressure threshold. At this moment, the actuator 98 shifts into its blocking position due to the pressure that is still present in the first control chamber 60 when the trigger valve 22 is actuated continuously. From this point onwards, further contact initiation is not possible.

Based on Figures 4 to 9 construction details are explained in more detail. In each of these figures, one can see the trigger 14, which is pivotably mounted about a pivot axis 86, and the slide 30 of the touchdown sensor 24. This can move up and down when the touchdown sensor valve 24 is actuated, around the valve pin 88 of the touchdown sensor valve 18 against the force to shift a spring 134 into an actuated position. The trigger valve 22 also has a valve pin 90 which can be displaced into an actuated position against the force of a spring 92. This is done directly by interacting with the trigger 14.

Figure 4 shows the initial state in which touch-down sensor valve 18 and trigger valve 22 are each drawn in their unactuated position. The safety valve arrangement 16 has, as the actuator 98, a blocking sleeve 144 which surrounds a valve sleeve 146 of the touchdown sensor valve 18.

The pressurized housing interior 64 is blocked by the O-ring 148 from the line 38 leading to an inlet of the touch-down sensor valve 18. Instead, the line 38 is connected to outside air via the radial bore 150 and the annular gap 152 of the trigger valve 22.

The main control line 82 is also connected to the outside air, namely via a radial bore 154 in the locking sleeve 144, which is in its open position, a radial bore 156 in the valve sleeve 146 and an annular gap 158 of the touch-down sensor valve 18. At the same time, the radial bore 156 in the valve sleeve 146 and thus also the main control line 82 is shut off from the line 38 by the O-ring 160 of the touch-down sensor valve 18 located in the seal.

The first control chamber 60, which is connected to the line 38, is located above the locking sleeve 144. The pressure in this first control chamber 60 acts on the locking sleeve 144 via an annular surface 162 of the locking sleeve 144 and searches for this in the Figure 4 to shift down to the locked position.

The second control chamber 62 is located below the locking sleeve 144 and acts on the locking sleeve 144 via two ring surfaces 164, 166. The pressure in the second control chamber 62 therefore tries the locking sleeve 144 in the open position shown, that is in the Fig. 4 to shift up. The spring 84 also exerts a force in this direction on the locking sleeve 144.

The second control chamber 62 has a relatively large volume and is therefore at the same time a storage chamber 130. The second control chamber 62 or the storage chamber 130 is connected to outside air via the throttle 132.

Figure 5 shows the arrangement Figure 4 after attaching the pneumatic nailer 10 to a workpiece. For a better overview are in the Figures 5 to 9 only provide the elements mentioned for these figures with reference numerals. One recognizes in Fig. 5 that the slide 30 of the touchdown sensor 24 has shifted upward and has moved the valve pin 88 upward, as a result of which the touchdown sensor valve 18 has been moved into the actuated position. As a result of this measure, the O-ring 160 has moved out of the seal, so that the line 38 is now connected to the main control line 82 via the contact sensor valve 18 and its radial bore 156 and the radial bore 154 in the locking sleeve 144. At the same time, the O-ring 188 seals the lines 124, 126 against outside air. Since the trigger valve 22 is still in its unactuated position, the line 38 is vented, so that the actuation of the touch-down sensor valve 18 has no further effect.

If the trigger 14 and thus the trigger valve 22 is actuated, as in the Figure 6 shown, the O-ring 148 moves out of the seal, so that the line 38 is vented. At the same time, the O-ring 168 seals this line 38 from outside air. The first control chamber 60 connected to the line 38 is also ventilated.

The valve sleeve 146 has a radial bore 170 and an O-ring 172 closing it. The radial bore 170 and the O-ring 172 together form the check valve 128. About this check valve 128 in the in Figure 6 situation shown, the second control chamber 62 is also ventilated via line 38. For this purpose, the air flows through the check valve 128 and further through an annular gap 174 formed between the valve sleeve 146 and the blocking sleeve 144. This ventilation of the second control chamber 62 takes place approximately at the same time as the ventilation of the first control chamber 60, so that the two control rooms 60, 62 forces exerted on the locking sleeve 144 take effect approximately simultaneously. By suitable dimensioning of the ring surfaces 160, 164, 166 mentioned (see Fig. 4 ) and the force of the spring 84, this means that the locking sleeve 144 remains in its open position. Therefore, the ventilation of the line 38 has the further consequence that the main control line 82 is ventilated and a driving-in process is triggered.

If the device is subsequently removed from the workpiece and the touchdown sensor 24 is relieved, the touchdown sensor valve 18 returns to its unactuated position. This is in Figure 7 shown. For a short time after the previous driving-in process, there is sufficient pressure in the second control chamber 62 to hold the locking sleeve 144 in its open position. During this period, contact actuation can be carried out at any time by actuating the touch-down sensor valve 24 again, which at the same time leads to a refreshing of the pressure in the second control chamber 62 on the route already outlined, so that the time window for a further contact initiation opens again.

However, if there is no further triggering of the contact, the pressure in the storage chamber 130 and the second control chamber 62 slowly drops by venting via the throttle 132 until the locking sleeve 144 moves downward into its locking position, as in FIG Figure 8 shown. As a result, the annular gap 174 is sealed by the O-ring 176 arranged on the valve sleeve 146, so that ventilation of the second control chamber 62 via the check valve 128 is no longer possible. At the same time, the O-ring 178 also arranged on the valve sleeve 146 closes an annular gap between the valve sleeve 146 and the locking sleeve 144, via which there was previously a connection between the radial bore 156 of the valve sleeve 146 and the radial bore 154 of the locking sleeve 144. As a result, the main control line 82 is blocked by the line 38.

Furthermore, the in Figure 8 Room labeled 180 connected to outside air via a hole that is not visible. Because of the two O-rings 182, 184 of the locking sleeve 144, which are not in the seal, this leads to a venting of the main control line 82 via the radial bore 154 of the locking sleeve 144 and the second control chamber 62, which is now connected to the space 180 via the annular gap 186 .

The locking sleeve 144 is now in her for so long Figure 8 shown blocking position, how the trigger 14 remains actuated.

Then, as in Figure 9 shown, the touchdown sensor 24 and thus the touchdown sensor valve 18 actuated, this does not result in a ventilation of the main control line 82 or a ventilation of the second control chamber 62 because of the O-rings 176 and 178 which are still in the seal.

List of reference symbols used:

10th

Pneumatic nailer

12th

Handle

14

trigger

16

Safety valve arrangement

18th

Touch sensor valve

20th

Control valve assembly

22

Trigger valve

24th

Touch sensor

26

muzzle

28

Muzzle tool

30th

Slider

32

first input of the trigger valve

34

second input of the trigger valve

36

Trigger valve output

38

management

40

first input of the touch-down sensor valve

42

second input of the touch-down sensor valve

44

Outlet sensor valve output

46

admission

48

magazine

50

Driving plunger

52

Piston

54

Working cylinder

56

Main valve

58

Pilot valve

60

first control room

62

second control room

64

Housing interior

66

first output of the safety valve arrangement

68

second outlet of the safety valve arrangement

70

Annular gap

72

room

74

first input of the safety valve arrangement

76

second input of the safety valve arrangement

78

third input of the safety valve arrangement

80

fourth input of the safety valve arrangement

82

Main control line

84

feather

86

Swivel axis

88

Valve pin

90

Valve pin

92

feather

94

Control piston

96

Guide sleeve

98

Actuator

100

lower o-ring

102

feather

104

middle O-ring

106

upper o-ring

108

Vent

110

Control line

112

radial bore

114

room

116

Main valve actuator

118

O-ring

120

feather

122

Ring surface

124

management

126

management

128

check valve

130

Storage chamber

132

throttle

134

feather

140

lower housing part

142

Housing cap

144

Locking sleeve

146

Valve sleeve

148

O-ring

150

radial bore of the trigger valve

152

Annular gap of the trigger valve

154

radial bore of the locking sleeve

156

radial bore of the valve sleeve

158

Annular gap of the surface-mounted sensor valve

160

O-ring

162

Ring surface

164

Ring surface

166

Ring surface

168

O-ring

170

radial bore of the check valve

172

Check valve o-ring

174

Annular gap

176

O-ring

178

O-ring

180

room

182

O-ring

184

O-ring

186

Annular gap

188

O-ring

Claims (14)

1. A pneumatic nail gun (10) with:

   • a working piston (52) which is connected to a driving tappet (50) for driving in a fastening means and to which compressed air is applied when a driving process is triggered,

   • a trigger (14) and a placing sensor (24) which, when actuated jointly, can aerate or deaerate a main control line (82) and as a result trigger a driving process,

   • a control valve assembly (20) which has a trigger valve (22) assigned to the trigger (14) and a placing sensor valve (18) assigned to the placing sensor (24), and

   • a safety valve assembly (16) which is displaceable between a locked position and an open position by controlling the pressure in a first control space (60) and the pressure in a second control space (62), wherein

   • in the open position, the main control line (82) is connected to the control valve assembly (20) and, in the locked position, is not connected to the control valve assembly (20),

   • the first control space (60) is connected to the trigger valve (22) such that an actuation of the trigger valve (22) seeks to bring the safety valve assembly (16) into the locked position, and

   • in the open position, the second control space (62) is connected to the placing sensor valve (18) such that an actuation of the placing sensor valve (18) always seeks to bring the safety valve assembly (16) into the open position when the trigger valve (22) is actuated.
2. The pneumatic nail gun (10) according to claim 1, characterized in that the safety valve assembly (16) comprises a single actuating member (98) which is displaceable between the locked position and the open position, wherein a pressure in the first control space (60) exerts a first force on the actuating member (98), and a pressure in the second control space (62) exerts a second force on the actuating member (98) counter to the first force.
3. The pneumatic nail gun (10) according to claim 2, characterized by a spring (84) which exerts a force on the actuating member (98) in the direction of the open position.
4. The pneumatic nail gun (10) according to one of claims 1 to 3, characterized in that each actuation of the trigger valve (22) effectuates an aeration of the first control space (60).
5. The pneumatic nail gun (10) according to one of claims 1 to 4, characterized in that the trigger valve (22) is actuated with each actuation of the trigger (14), irrespective of a position of the placing sensor (24).
6. The pneumatic nail gun (10) according to one of claims 1 to 5, characterized in that the placing sensor valve (18) is actuated with each actuation of the placing sensor (24), irrespective of a position of the trigger (14).
7. The pneumatic nail gun (10) according to one of claims 1 to 6, characterized in that in the open position, the main control line (82) is connected to an outlet (44) of the placing sensor valve (18), and an inlet (40) of the placing sensor valve (18) is connected to an outlet (36) of the trigger valve (22).
8. The pneumatic nail gun (10) according to one of claims 1 to 7, characterized in that a non-return valve (128) is arranged in a line (126) which, in the open position, connects the placing sensor valve (18) to the second control space (62).
9. The pneumatic nail gun (10) according to one of claims 1 to 8, characterized in that the second control space (62) is deaerated via a throttle (132) and is connected to a storage chamber (130).
10. The pneumatic nail gun (10) according to one of claims 1 to 9, characterized in that, in the locked position, the safety valve assembly (16) deaerates the second control space (62).
11. The pneumatic nail gun (10) according to one of claims 1 to 10, characterized in that, in the locked position, the safety valve assembly (16) deaerates the main control line (82).
12. The pneumatic nail gun (10) according to one of claims 1 to 11, characterized in that the safety valve assembly (16) has a locking sleeve (144) as an actuator (98), within which the placing sensor valve (18) is arranged.
13. The pneumatic nail gun (10) according to claim 12, characterized in that the placing sensor valve (18) comprises a fixedly arranged valve sleeve (146) and a displaceable valve pin (88) guided therein, wherein the locking sleeve (144) surrounds the valve sleeve (146) and cooperates therewith.
14. The pneumatic nail gun (10) according to claim 13, characterized in that the non-return valve (128) is formed by an O-ring (172) which is inserted into a peripheral groove of the valve sleeve (146).

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