Compressed air nailer with safety device

Abstract

The invention relates to a compressed air nail driver, which comprises: a working piston, which is connected to a driving rod for driving a fixing device and is loaded with compressed air when the driving process is triggered; a trigger (26) and a seating sensor (28), whose joint operation can trigger the driving process; a safety device, which has a control volume (72) and is constructed to automatically take safety measures when a pressure threshold value in the control volume is exceeded or fallen below, wherein the control volume is ventilated or exhausted by a throttle valve in such a way that a delay time is predetermined by the volume of the control volume (72) and the opening cross section of the throttle valve, after which the pressure threshold value is exceeded or fallen below, wherein: the control volume has a volume in the range of 0.5 ml to 20 ml, and the throttle valve is a hole with a diameter in the range of 30 μm to 200 μm.

Description

Technical Field

[0001] The invention relates to a compressed air nailer, which comprises a trigger, a seating sensor and a safety device. When the compressed air nailer is placed on a workpiece, the seating sensor is displaced against the force of a spring until the muzzle tool is in contact with or almost in contact with the workpiece. Only when the seating sensor is operated in this way can the insertion process be triggered. As a result, the compressed air nailer has significantly better safety against accidental triggering than devices without a seating sensor. Background Art

[0002] Some compressed air nailers of the described type can be used in two different modes: In the so-called single trigger, the compressed air nailer is first placed on the workpiece and the seating sensor is thereby activated. Subsequently, the trigger is manually operated and a single insertion process is thereby triggered. In the so-called contact trigger, also called "touch", the user already keeps the trigger pressed while the compressed air nailer is placed on the workpiece. When placed on the workpiece, the seating sensor is activated and the insertion process is thereby triggered. The compressed air nailer can be placed repeatedly in rapid sequence, which enables very fast work, in particular when a plurality of fixing devices have to be pushed in for adequate fixing and only slight requirements are placed on the positioning accuracy of the fixing devices.

[0003] However, in certain situations, the contact trigger method is subject to an increased risk of injury. For example, if the user keeps the hand-operated trigger pressed, the insertion process can be triggered if the user inadvertently touches the object or body part with the seat sensor, not only when the user wants to place the compressed air nailer on the same workpiece a few centimeters away from the last inserted fixing element, but also when the user changes to another workpiece arranged further away. For example, an accident can occur if the user (ignoring important safety regulations) climbs up a ladder with the compressed air nailer, where the trigger is kept pressed and the user inadvertently rubs his leg with the seat sensor.

[0004] Some known compressed air nailers attempt to reduce the risk associated with contact triggering operation by making contact triggering possible only in a short period of time after operating the trigger or after the push-in process. If this period of time ends, the trigger must first be released again. An example of this is known from document EP 2 767 365 B1. The compressed air nailer described therein has a trigger and a seat sensor, which are respectively associated with a control valve. In addition, the known device has a safety control chamber, whose pressure acts on the locking piston. The triggering of the push-in process is prevented in a specific position of the locking piston. The safety control chamber is ventilated by the control valve and throttle valve associated with the trigger. Thus, after operating the trigger, contact triggering is possible only in the time until the pressure in the safety control chamber exceeds a preset pressure threshold. Thereafter, the compressed air nailer is locked until the trigger is released and the pressure in the safety control chamber drops below the pressure threshold again.

[0005] A similar function is provided by the compressed air nailer disclosed in U.S. Patent 3,964,659, which can also be used for single trigger operation and contact trigger operation, and in which the trigger and the seating sensor are mechanically connected via a pressure plate (Wippe). The pressure plate acts on the control valve to trigger the push-in process by exhausting the main control pipeline. If only the trigger but not the seating sensor is operated, the control pin of the control valve is displaced only over a portion of its adjustment stroke. This half-operation of the control valve causes the control chamber to be slowly ventilated through a small, adjustable ventilation opening. The pressure existing in the control chamber acts on the valve sleeve surrounding the control valve and finally displaces the valve sleeve into a locked position, in which the complete operation of the valve pin can no longer exhaust the main control pipeline, so that contact triggering is impossible.

[0006] If the first push-in process must always be implemented by a single trigger, safety can be further improved. In this case, the device must first be placed at the workpiece for the first push-in process, thereby operating the seat sensor. Then, the subsequent operation of the trigger triggers the first push-in process. Then, it can be triggered by contact in a short period of time, that is, by repeatedly lifting and placing the device on the workpiece while continuing to operate the trigger, to carry out another push-in process. This functionality is provided in the compressed air nailer described in document DE 10 2013 106 657 A1. For this reason, the trigger and the seat sensor are mechanically connected by the pressing plate acting on the control valve to trigger the push-in process. In each push-in process, a pressure is established in the control chamber of a relatively large volume, which surrounds the working cylinder annularly, and the pressure acts on the mechanical actuator (Stel lgl ied). The control chamber is slowly exhausted via the exhaust opening in the wall of the working cylinder. Depending on the pressure in the control chamber, the actuator reaches a locked position, thereby preventing the seat sensor from mechanically acting on the pressing plate when operating the trigger, and making contact triggering impossible.

[0007] A compressed air nailer is known from document WO 2019 / 038124 Al, in which the functionality described is implemented pneumatically. To this end, the control chamber is ventilated through the control valve when the control valve is operated. The delay time of the compressed air nailer returning from the contact trigger operation to the single trigger operation thereafter is generated by the slow exhaust of the control chamber through the throttle valve. In one embodiment, the control chamber transitions to a smaller first storage chamber, which is connected to a larger second storage chamber through a first throttle valve. When the push-in process is triggered, the smaller storage chamber is ventilated through the control valve. Additionally, the larger storage chamber is ventilated by the return chamber (Rückholkammer). Slow exhaust is performed through a second throttle valve, which connects the second storage chamber to the outside air. In this way, a larger amount of air can be fully utilized to set the delay time compared to the amount of air provided by the control valve alone in the available time. This should allow the use of a throttle valve which is easy to produce, has a relatively large opening cross section and is not susceptible to malfunctions, in particular in the form of a small hole with a diameter in the range of 0.1 mm to 1 mm. Summary of the invention

[0008] Based on this, the object of the present invention is to provide a compressed air nail driver with a compact structure and a simple, strong and reliable safety mechanism.

[0009] This object is achieved by a compressed air nailer. For advantageous design solutions, please refer to the specific implementation.

[0010] The compressed air nailer has

[0011] a working piston which is connected to an insertion rod for inserting the fixing element and is acted upon by compressed air when the insertion process is triggered,

[0012] A trigger and a seat sensor, which together trigger the push-in process,

[0013] a safety device having a control volume and being designed to automatically initiate safety measures when a pressure threshold value in the control volume is exceeded or fallen below, wherein the control volume is ventilated or exhausted via a throttle valve in such a way that a delay time is predetermined by the volume of the control volume and the opening cross section of the throttle valve, after the expiration of which the pressure threshold value is exceeded or fallen below, wherein

[0014] The control volume has a volume in the range of 0.5 ml to 20 ml and the throttle is an orifice with a diameter in the range of 30 μm to 200 μm.

[0015] The compressed air nailer is used to push in fixing elements, such as nails, pins or clips. For this purpose, the compressed air nailer can have a magazine for fixing elements, from which the fixing elements are respectively delivered to the receiving part of the muzzle tool of the compressed air nailer. When the pushing process is triggered, the working piston of the compressed air nailer is loaded with compressed air. The working piston drives a pushing rod connected to the working piston. The pushing rod strikes the rear end of the fixing element in the receiving part of the muzzle tool and pushes the fixing element into the workpiece.

[0016] The seating sensor can be a mechanical structural element which projects beyond the front end of the muzzle tool and is held in this position by a spring until the compressed air nailer is placed on the workpiece. The seating sensor is then displaced against the direction of the spring force and against the insertion direction until the muzzle tool of the compressed air nailer rests against the workpiece or almost rests against the workpiece. As a further operating element, the compressed air nailer has a trigger, for example in the form of a trigger lever that can be operated by a finger.

[0017] The safety device is responsible for preventing the insertion process from being triggered in certain potentially dangerous situations. For this purpose, it automatically takes safety measures, which result in the insertion process not being triggered despite the joint operation of the seat sensor and the trigger. For example, the safety measure can be that the compressed air nailer is disconnected from the pressure supply line and completely vented. However, less stringent safety measures are also possible, in particular those that put the compressed air nailer into a state of operational readiness again by simply releasing the trigger for a short time. The details of this will be explained later.

[0018] As in the prior art discussed at the beginning, especially in the document WO2019 / 038124A1, the safety device automatically performs safety measures after the delay time has expired. The delay time starts from a specific event, such as the operation of a trigger or a previous push-in process. At this point in time, the pressure in the control volume may have a certain starting value, such as an operating pressure or an ambient pressure. From this point in time, the control volume is ventilated or exhausted via a throttle valve until the pressure in the control volume exceeds or falls below a preset pressure threshold. At this point in time, the delay time ends. Therefore, the duration of the delay time is determined by the volume of the control chamber and the opening cross section of the throttle valve.

[0019] In the present invention, the volume of the control volume ranges from 0.5 ml to 20 ml, in particular from 0.5 ml to 10 ml, from 0.5 ml to 5 ml, from 0.5 ml to 2 ml or from 1 ml to 1.5 ml. The throttle valve is a hole with a diameter in the range of 30 μm to 200 μm, in particular in the range of 30 μm to 95 μm, in the range of 40 μm to 80 μm or in the range of 60 μm to 80 μm. The hole can in particular have a substantially circular cross section. Thus, a relatively small volume is combined with a small opening cross section to obtain a suitable delay time. Unlike what is known in the prior art in combination with a small control volume, a simple small hole is used instead of a throttle valve, wherein the opening cross section of the throttle valve is formed by an adjustable annular gap. A particularly compact, simply constructed structure is achieved by these measures.

[0020] Furthermore, the inventors have recognized that annular gaps with sufficiently small opening cross sections have very small gap widths, which can be, for example, in the range of a few μm or less, and such annular gaps tend to become clogged over time during the operation of the compressed air nailer. This is detrimental to the safety of the device, since as a result, the delay time can continue to be prolonged unnoticed until the safety device can no longer respond at all. It is assumed that very small particles are responsible for the clogging of the annular gap, the intrusion of which into the compressed air nailer can hardly be prevented, since such particles, especially fine dust, can already be contained in a certain concentration in the compressed air used to operate the device. Although the holes used in the present invention have an opening cross section similar to that of the annular gap, the diameter of the holes is significantly greater than the width of the annular gap. The inventors have found that when using a hole instead of a throttle valve with an annular gap, the safety device is significantly less sensitive to contaminants, and this is due to the different sizes of the corresponding openings.

[0021] In summary, the invention provides a structurally simple, compact and particularly reliable safety device.

[0022] In one embodiment, the hole is produced by laser drilling. In principle, the hole can be produced by any method, in particular by cutting methods with conventional drills or milling cutters.

[0023] However, the production of very small holes by cutting methods is difficult and requires expensive and sensitive special tools that wear out quickly. Laser drilling is an alternative, in which the material in which the hole is drilled is not cut, but evaporated and / or liquefied with the aid of a laser. Unlike cutting methods, it is not possible to achieve an exactly cylindrical hole in laser drilling. However, this is not critical for the present invention. What is more important is the reproducibility of the hole dimensions that can be achieved effortlessly with the required quality during laser drilling. A particular advantage of laser drilling compared to cutting methods is the contour of the hole edge that is as burr-free as possible, which is significant in the present invention with regard to possible "sticking" of contamination particles.

[0024] In one design, the hole has a length in the range of 30 μm to 1 mm. This means that the component into which the hole is introduced has a corresponding thickness at the directly adjacent hole. For this purpose, the material thickness of the component in the region of the hole can be reduced accordingly before the hole is manufactured. The length of the hole affects the compressed air flow through the hole as its diameter. Therefore, for the small compressed air flow desired to achieve an appropriate delay time when the control volume is small, a relatively long hole is meaningful in some cases. Tests have shown that the length of the hole in the range is practical in many cases. Here, it may be difficult to manufacture a particularly long hole. Therefore, a length in the range of 30 μm to 200 μm, especially in the range of 40 μm to 100 μm, is particularly suitable. The hole can have the same diameter over its entire length, i.e., it is precisely cylindrical. However, this is not necessary for the present invention, and it is usually not a problem depending on the manufacturing deviation, such as a certain taper of the drilled hole (such a taper will occur during laser drilling). If the hole deviates from the exact cylindrical shape, then the average value of the diameter over the length of the hole or the minimum diameter of the hole can be considered as the diameter of the hole.

[0025] In one design, the compressed air nail driver has a first control valve, which is controlled each time the trigger is operated, wherein the control volume is ventilated or exhausted via the first control valve. The first control valve is associated with the trigger and is therefore sometimes also referred to as a trigger valve. For example, the first control valve can have a valve pin, which is directly displaced by the operating surface of the trigger lever when the trigger is operated. Due to this operation, the first control valve establishes a connection for ventilation or exhaust of the control volume, for example a connection between the control volume and a chamber permanently under operating pressure or a connection between the control volume and the outside air. In this design, the delay time described can start with the operation of the trigger.

[0026] In one design, the compressed air nailer has a second control valve, which is controlled each time the seat sensor is operated or each time the trigger and the seat sensor are operated together, wherein the main control pipeline is ventilated and / or exhausted via the second control valve. The second control valve is associated with the seat sensor and is therefore sometimes also referred to as a seat sensor valve. Whether the seat sensor is controlled each time the seat sensor is operated or only when the trigger is also operated at the same time depends on the structural form of the compressed air nailer. These two variants will also be explained in conjunction with the embodiments. In any case, the effect of the control of the second control valve is that the main control pipeline is ventilated and / or exhausted. For this purpose, the second control valve can be connected between the main control pipeline and a chamber that is permanently under operating pressure or between the main control pipeline and the external air. The ventilation or exhaust of the main control pipeline can guide the push-in process. For this purpose, for example, a known embodiment with a main valve and a pilot valve is controlled by the main control pipeline. However, other structures with or without a pilot valve can also be considered. It is only essential for the embodiment of the invention that the pushing-in process can be triggered by venting or exhausting the main control line.

[0027] In one embodiment, the control volume comprises an annular volume which surrounds the control valve. In principle, the control volume can have any geometric shape. However, in many constructions of compressed air nailers, the available construction space is limited, so that even a relatively small control volume cannot be easily accommodated in the present invention. The use of an annular volume around the control valve takes this into account. The control valve can in particular be the first control valve or the second control valve.

[0028] In one design, the compressed air nailer comprises a housing having a recess in which a control valve assembly is arranged, wherein the control volume is completely or mostly arranged in the recess. The housing can, for example, surround a working cylinder of the compressed air nailer and / or have a gripping section. The recess can, for example, be arranged inside the gripping section. The control valve assembly can in particular include the first control valve described and / or the second control valve described. The control valve assembly can be sealed relative to the surrounding housing. The control volume can be located between the control valve assembly and the housing. In this design, a particularly compact and structurally simple construction is obtained.

[0029] In one embodiment, the hole is arranged in a replaceable component of the compressed air nail driver. The replaceable component is in particular a component that is different from the housing of the compressed air nail driver, such as an element of a control valve assembly or an element of a compressed air line. On the one hand, this embodiment allows for simplified maintenance or repair of the hole, for example, to completely protect it from contamination or corrosion. On the other hand, by simply replacing the replaceable component, by using replaceable components with different hole diameters and / or hole lengths, the delay time can be matched to the corresponding requirements.

[0030] For the purpose mentioned last, in another embodiment, it is considered that there is at least one second sample for the replaceable component, which differs from the replaceable component in terms of the diameter and / or length of the hole. In particular, a compressed air nail driver with a replaceable component and at least one second sample of the replaceable component can be provided in a kit.

[0031] In one embodiment, the replaceable component is a valve sleeve. In particular, it can be a valve sleeve of a first control valve, thereby achieving a particularly simple and compact structure for ventilating or exhausting a control volume through a hole and controlled by the first control valve.

[0032] In one embodiment, the safety measure is to place the compressed air nail driver in a locked state, in which the pushing process cannot be triggered. For example, the compressed air nail driver can have a locking piston, which is mechanically engaged in the process required to trigger the pushing process, for example in such a way that the locking piston prevents the displacement of the actuator of the pilot valve. As an alternative, the locked state can be produced in such a way that the compressed air supply to the compressed air nail driver is cut off by means of a shut-off valve and / or the compressed air nail driver is completely ventilated. It is also possible to establish the locked state in such a way that a control line is opened or cut off by means of a shut-off valve, which control line must be ventilated or ventilated in order to trigger the pushing process. The control line can in particular be the main control line already mentioned.

[0033] In one design, the compressed air nailer can be operated in contact triggering operation and single triggering operation, and the safety measure is to switch the compressed air nailer from contact triggering operation to single triggering operation. As mentioned at the beginning, the operational safety of the compressed air nailer can also be improved by this measure. After the compressed air nailer is placed in single triggering operation, contact triggering is not possible. Instead, a single triggering must be performed first, which is usually possible again when the trigger is released in advance.

[0034] In one embodiment, the compressed air nail driver has a locking sleeve that can be displaced between a locking position and an open position, wherein the locking sleeve blocks the connection between the main control line and the control valve in the locking position and opens the connection between the main control line and the control valve in the open position. In this embodiment, the safety measure can basically consist in that the locking sleeve is displaced into the locking position. The locking sleeve can be integrated in a control valve assembly that includes the first control valve and / or the second control valve. In particular, the locking sleeve can accommodate the second control valve described in its interior.

[0035] In one embodiment, the locking sleeve is loaded with the pressure in the control volume. In this way, the position of the locking sleeve is directly influenced by the pressure present in the control volume. The force exerted by the pressure can be combined with another pneumatically generated reaction force and / or the force of a spring. BRIEF DESCRIPTION OF THE DRAWINGS

[0036] The invention is described in more detail below with reference to two exemplary embodiments shown in the drawings.

[0037] Figure 1 A compressed air nailer is shown, which has a control valve assembly shown in a cross-sectional view and other elements which are only shown schematically,

[0038] Figure 2 The enlarged view shows Figure 1 Control valve components,

[0039] Figure 3 Shows the seat sensor after operation Figure 1 The control valve components in

[0040] Figure 4 Shows the following after the trigger is operated Figure 1 The control valve assembly in

[0041] Figure 5 Shows the compressed air nailer after it has been removed from the workpiece. Figure 1 Control valve components,

[0042] Figure 6 Shows the delay time after the end of Figure 1 The control valve assembly in

[0043] Figure 7 A control valve assembly of another compressed air nailer is shown in a cross-sectional view.

[0044] Figure 8 Shows the following after the trigger is operated Figure 7 The control valve assembly in

[0045] Fig. 9Shown after operating the seat sensor Figure 7 The control valve assembly in

[0046] Fig.10 Shows the compressed air nailer after it has been removed from the workpiece. Figure 7 control valve components. DETAILED DESCRIPTION

[0047] Figure 1 The compressed air nailer in the embodiment comprises a working piston 10, which is connected to a push rod 12. The working piston 10 is movably supported in a working cylinder 14. If the working piston is loaded with compressed air above the working piston 10, a fixing device (not shown) can be pushed into the workpiece by the push rod 12. A main valve 16 is located above the working cylinder 14, which is responsible for supplying compressed air to the working cylinder 14 from a compressed air storage device (not shown) or a compressed air interface in the compressed air nailer. The main valve 16 is controlled by a pilot valve 18. The pilot valve 18 is in turn controlled by a main control line 20. Once the main control line 20 is ventilated, the pilot valve 18 switches and then the main valve 16 switches and the pushing process is triggered.

[0048] Figure 1 All the elements described so far are only schematically shown. The specific design of these elements can be found, for example, in the appendix to document WO 2019 / 038124 A1. Figure 1 and 2 The structures described in this document are suitable for use with the present invention.

[0049] In order to understand the present invention, Figure 1 The elements shown in cross-section in FIG. 2 are important and are collectively referred to as control valve assemblies. They are responsible for controlling the pressure in the main control line 20 and thus for triggering the push-in process. These elements include a first control valve 22, a second control valve 24, a trigger 26 and a seat sensor 28. Figure 1 Only the upper end of the seat sensor 28 is shown in the cross-sectional view of FIG. In addition, the seat sensor 28 includes a lower end 104, which is Figure 1 Schematically shown in FIG. 1 and protruding beyond the opening of a muzzle tool (Mündungswerkzeug) not shown. Details of the control valve assembly are provided by means of Figure 2 The enlarged view of is further elaborated.

[0050] Figure 2The control valve assembly is shown in the starting state of the compressed air nailer, wherein the trigger 26 and the seating sensor 28 are not operated and the compressed air nailer is appropriately connected to a compressed air source. The housing cavity 32 (also shown only partially) arranged inside the housing 30, which is only partially visible, is always under operating pressure. Figure 2 The right edge of the compressed air nail driver transitions into the grip section 34.

[0051] The trigger 26 is supported at the housing 30 so as to be swingable around a housing-fixed shaft 36. The trigger has an operating surface 38 at its rear end, by means of which the valve pin 40 of the first control valve 22 can be displaced. The rear end of the seat sensor 28 cooperates with a seat sensor lever 42 which is partially arranged in a recess of the trigger 26. At the rear end, the seat sensor lever 42 is supported at the housing 30 so as to be swingable around a housing-fixed shaft 44. When the seat sensor 28 moves upward relative to the housing 30 when the compressed air nailer is placed on the workpiece, the front end of the seat sensor lever 42 is driven by the rear end of the seat sensor 28. As a result, the operating surface 46 of the seat sensor lever 42 displaces the valve pin 48 of the second control valve 24 upward.

[0052] The first control valve 22 includes a lower valve sleeve 50 and an upper valve sleeve 52. A small hole 54 is arranged in the lower valve sleeve 50 in the transverse direction. The hole 54 has a diameter of about 70 μm and a length of about 200 μm. Due to this very small size, the hole 54 is Figure 2 54. The chamber 56 arranged in the lower valve sleeve 50 adjacent to the bore 54 is continuously connected to the outside air via a transverse bore 106 in the upper valve sleeve 52 and an obliquely arranged bore 108 in the housing 30. Another continuous connection between the chamber 56 and the outside air is formed via an annular gap 58 between the valve pin 40 and the lower valve sleeve 50.

[0053] In the illustrated position of the first control valve 22 , the lower O-ring 60 on the valve pin 40 is not in sealing, so that the obliquely arranged hole 64 and the chamber 66 connected thereto above the locking sleeve 68 surrounding the second control valve 24 are also vented via the transverse hole 62 in the upper valve sleeve 52 .

[0054] In the starting state shown, the locking sleeve 68 is in the upper end position, in which it is held by the force of the spring 70. This upper end position is the open position. Another force acting on the locking sleeve 68 is exerted by the pressure in the control volume 72 surrounded by the second control valve 24. In the starting state shown, this force is zero, because the control volume 72 is not yet loaded with compressed air and is connected to the outside air via the hole 54. In the exemplary embodiment shown, the control volume 72 has a volume in the range between 1 ml and 1.5 ml.

[0055] As long as the valve pin 48 of the second control valve 24 is in its non-actuated position, the lower O-ring 74 on the valve pin 48 does not seal. Likewise, the upper O-ring 76 on the valve sleeve 78 of the second control valve 24 does not seal. Therefore, the main control line 20 is connected to the outside air via the transverse hole 80 in the blocking sleeve 68, through the upper O-ring 76, via the transverse hole 82, the annular gap 84 between the valve pin 48 and the valve sleeve 78, and via the O-ring 74.

[0056] If from Figure 2 The seat sensor 28 is operated from the state shown in FIG. 1 , and the valve pin 48 of the second control valve 24 is displaced to its operating position against the force of the spring 86. Figure 3 , in which the O-ring 74 is in the seal. The main control line 20 is thus blocked from the outside air. Furthermore, the displacement of the valve pin 48 causes its upper O-ring 88 to be released from the seal, so that a connection is established between the chamber 66 and the main control line 20, i.e., via the O-ring 88, via the transverse bore 82, via the O-ring 76 and through the transverse bore 80. Since the chamber 66 is still pressure-free, the push-in process is not triggered.

[0057] If the trigger 26 is also operated in the next step, as in Figure 4 As shown in , the valve pin 40 of the first control valve 22 moves into its actuated position, and the lower O-ring 60 obtains a seal and the upper O-ring 90 of the valve pin 40 is released from the seal. Therefore, a connection is formed between the housing interior 32, which is always ventilated, and the chamber 66 via the transverse hole 62 in the upper valve sleeve 52. This causes an immediate ventilation of the main control line 20 via the connection already described, thereby triggering the pushing process. In addition, the control volume 72 is ventilated through the check valve formed by the middle O-ring 92 on the valve sleeve 78. Therefore, the control volume 72 is then also at the operating pressure like the chamber 66. In addition, the three forces acting on the locking sleeve 68 act together so that the locking sleeve 68 remains in its upper end position.

[0058] If the compressed air nailer is removed from the workpiece, the seat sensor 28 moves back downward, so that the valve pin 48 of the second control valve 24 also returns to its starting position, as shown in FIG. Figure 5 As a result, the upper O-ring 88 of the valve pin 48 moves back into the seal, so that no further compressed air can be delivered to the main control line 20 or the control volume 72. The pressure in the control volume 72 slowly decreases through the hole 54. The main control line 20 is already Figure 2 The connections described in ventilate to the outside air.

[0059] By re-operating the seat sensor 28, Figure 5Starting from the state shown, a contact triggering can be carried out at any time, because the main control line 20 can be ventilated again by the upward displacement of the valve pin 48. At the same time, the pressure in the control volume 72 is then refreshed by the non-return valve, so that the delay time during which another contact triggering can be carried out is restarted.

[0060] However, if the seat sensor 28 remains inactive for a certain period of time while the trigger 26 is actuated, the pressure in the control volume 72 drops below the preset pressure threshold. As a result, the balance of the three forces acting on the locking sleeve 68 changes, and the locking sleeve 68 reaches Figure 6 The lower end position of the shut-off sleeve 68 is shown. The lower end position is the shut-off position. In this position of the shut-off sleeve 68, the lower inner circumference of the shut-off sleeve 68 is sealed at the O-ring 94, so that it is no longer possible to supply compressed air to the control volume 72 via the non-return valve. In addition, the upper O-ring 76 on the valve sleeve 78 is sealed, so that it is also no longer possible to supply compressed air to the main control line 20 via the transverse bore 80.

[0061] In addition, Figure 6 The chamber 96 in the figure is connected to the outside air via a non-visible hole. Since the intermediate O-ring 98 on the locking sleeve 68 is not in a seal, the main control line 20 is vented via the chamber 96. Therefore, the movement of the locking sleeve 68 into its locked position is a safety measure that reliably prevents the triggering of another push-in process. Another push-in process can only be triggered when the trigger 26 is released and the chamber 66 is vented, so that the locking sleeve 68 is displaced back into its open position.

[0062] The second embodiment uses the attached Figures 7 to 10 Explain. Figure 1 The schematically shown elements and the configuration of the second control valve 24 with the shut-off sleeve 68 are similar to Figures 1 to 6 Elements which are used unchanged are provided with the same reference numerals as in the first exemplary embodiment if necessary and are not explained again.

[0063] There is a difference in the seating sensor lever 42, in that its rear end is not fixed to the housing, but is hinged at the rear end of the trigger 26. This results in the valve pin 48 of the second control valve 24 not being controlled every time the seating sensor 28 is operated, but only being controlled when the trigger 26 and the seating sensor 28 are operated together. In addition, the chamber 66 above the locking sleeve 68 is not ventilated via the first control valve 22, but is continuously connected to the housing inner chamber 32 via the hole 100.

[0064] The described changes with respect to the first exemplary embodiment allow a particularly simple design of the first control valve 22. This also includes the lower valve sleeve 50, in which the bore 54 is arranged, as explained in detail for the first exemplary embodiment. Unlike in the first exemplary embodiment, the first control valve 22 only fulfills the task of optionally ventilating or exhausting the control volume 72 via the bore 54. For this purpose, the first control valve 22 is Figure 7 In the inoperative position shown in FIG. 1 , the connection between the cavity 56 in the lower valve sleeve 50 and the housing cavity 32 is established via the upper O-ring 102, while the lower O-ring 60 is in a sealed state. The control volume 72 is thus slowly ventilated through the hole 54. After a certain time, after the compressed air nailer is connected to the compressed air source and neither the trigger 26 nor the seat sensor 28 is operated during this time, the compressed air nailer is in a Figure 7 The starting state shown is that the control volume 72 is at operating pressure and the shut-off sleeve 68 is in its open position.

[0065] Figure 8 The situation is shown after the operation of the trigger 26. The upper O-ring 102 of the valve pin 40 is in sealing and the control volume 72 is slowly vented via the orifice 54. Thus, the delay time starts with the operation of the trigger 26.

[0066] If the seating sensor 28 is operated while the trigger 26 continues to be operated before the delay time ends, the valve pin 48 of the second control valve 24 is displaced upward, as in Fig. 9 As shown in . The pushing process is thus triggered in the same manner as described in the first embodiment. As described in the first embodiment, the pressure in the control volume 72 is refreshed by the non-return valve formed by the intermediate O-ring 92 .

[0067] After the compressed air nail driver is lifted from the workpiece, the valve pin 48 of the second control valve 24 returns to its non-actuated position and the control volume 72 is slowly vented through the bore 54. As long as the pressure threshold in the control volume 72 is not fallen below, the locking sleeve 68 remains in its open position, so that this situation corresponds to Figure 8 Additional contact triggering is possible.

[0068] However, if the trigger 26 remains actuated without further triggering during the delay time, the locking sleeve 68 is displaced to its Fig.10 In the locking position shown, further triggering is prevented in the same manner as described in the first embodiment. To achieve another triggering, the trigger 26 must first be released again and wait until the pressure in the control volume 72 exceeds the pressure threshold and the locking sleeve 68 is displaced back to its open position. The device is then in the locking position again. Figure 8 The trigger ready state is shown.

[0069] In both embodiments, the housing 30 has two recesses, which respectively accommodate the first control valve 22 and the second control valve 24. The control volume 72 is located in the recess accommodating the second control valve 24.

[0070] List of reference numerals:

[0071] 10 Working piston

[0072] 12 Push rod

[0073] 14 Working cylinder

[0074] 16 Main valve

[0075] 18 Pilot valve

[0076] 20 Main control pipeline

[0077] 22 First control valve

[0078] 24 Second control valve

[0079] 26 Trigger

[0080] 28 Seat sensor

[0081] 30 Shell

[0082] 32 Shell cavity

[0083] 34 Grip Section

[0084] 36 Axis

[0085] 38 Operation surface

[0086] 40 Valve pin of the first control valve

[0087] 42 Trigger lever

[0088] 44 Axis

[0089] 46 Operation surface

[0090] 48 Valve pin of the second control valve

[0091] 50 Lower valve sleeve

[0092] 52 Upper valve sleeve

[0093] 54 holes

[0094] 56 Cavity in the lower valve sleeve

[0095] 58 Annular gap

[0096] 60 Lower O-ring

[0097] 62 lateral holes

[0098] 64 holes

[0099] 66 chambers

[0100] 68 Locking sleeve

[0101] 70 Spring

[0102] 72 Control Volume

[0103] 74 Lower O-ring

[0104] 76 Upper O-ring

[0105] 78 Valve sleeve

[0106] 80 Horizontal hole

[0107] 82 lateral holes

[0108] 84 Annular gap

[0109] 86 Spring

[0110] 88 Upper O-ring

[0111] 90 Upper O-ring

[0112] 92 intermediate O-ring (check valve)

[0113] 94 O-ring

[0114] 96 chambers

[0115] 98 intermediate O-ring

[0116] 100 holes

[0117] 102 Upper O-ring

[0118] 104 lower end

[0119] 106 lateral holes

[0120] 108 holes

Claims

1. Compressed air nail gun, with a working piston (10), which is connected to an insertion rod (12) for inserting the fixing element and is acted upon by compressed air when the insertion process is triggered, A trigger (26) and a seat sensor (28), which together can trigger the push-in process, A safety device having a control volume (72) and being designed to automatically initiate safety measures when a pressure threshold value in the control volume (72) is exceeded or fallen below, wherein: The control volume (72) is ventilated or exhausted via the throttle valve in such a way that a delay time is predetermined by the volume of the control volume (72) and the opening cross section of the throttle valve, after the expiration of which the pressure threshold value is exceeded or fallen below, wherein the control volume (72) has a volume in the range of 0.5 ml to 20 ml and the throttle is an orifice (54) having a diameter in the range of 30 μm to 95 μm, The compressed air nail driver has a locking sleeve (68) which can be displaced between a locking position and an open position, wherein the locking sleeve (68) blocks the connection between the main control line (20) and the control valve in the locking position and opens the connection between the main control line (20) and the control valve in the open position.

2. The compressed air nailer according to claim 1, characterized in that: The holes (54) are formed by laser drilling.

3. The compressed air nailer according to claim 1 or 2, characterized in that: The holes (54) have a length in the range of 30 μm to 1 mm.

4. The compressed air nail driver according to any one of claims 1 to 3, characterized in that: The compressed air nail driver has a first control valve (22) which is controlled each time a trigger (26) is actuated, wherein a control volume (72) is ventilated or exhausted via the first control valve (22).

5. The compressed air nail driver according to any one of claims 1 to 4, characterized in that: The compressed air nail driver has a second control valve (24), which is controlled each time the seating sensor (28) is operated or each time the trigger (26) and the seating sensor (28) are operated together, wherein the main control pipeline (20) is ventilated and / or exhausted via the second control valve (24).

6. The compressed air nail driver according to any one of claims 1 to 5, characterized in that: The control volume (72) includes an annular volume that surrounds a control valve.

7. The compressed air nail driver according to any one of claims 1 to 6, characterized in that: The compressed air nail driver comprises a housing (30) having a recess in which a control valve assembly is arranged, wherein the control volume (72) is completely or mostly arranged in the recess.

8. The compressed air nail driver according to any one of claims 1 to 7, characterized in that: The hole (54) is arranged in a replaceable component of the compressed air nail driver.

9. The compressed air nailer according to claim 8, characterized in that: There is at least one second sample for the exchangeable component, which differs from the exchangeable component in terms of the diameter and / or the length of the hole (54).

10. The compressed air nail driver according to claim 8 or 9, characterized in that: The replaceable component is a valve sleeve (50).

11. The compressed air nail driver according to any one of claims 1 to 10, characterized in that: The safety measure consists in that the compressed air nail driver is placed in a locked state, in which the insertion process cannot be triggered.

12. The compressed air nail driver according to any one of claims 1 to 11, characterized in that: The compressed air nail driver can be operated in a contact-trigger mode and a single-trigger mode, and the safety measure is that the compressed air nail driver is switched from the contact-trigger mode to the single-trigger mode.

13. The compressed air nail driver according to claim 1, characterized in that: The locking sleeve (68) is acted upon by the pressure in the control volume (72).

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