DRIVE-IN TOOL WITH IMPROVED SAFETY DEVICE

Abstract

A drive-in tool for driving fasteners into a workpiece, wherein the tool comprises in particular: a safety device for transferring the drive-in tool from a trip-ready state into a secured state after expiry of a delay, wherein the safety device comprises a control volume and an activation element, wherein in the first position of the activation element a charging connection is defined between the control volume and the gas pressure source connection, and wherein in the second position of the activation element a discharging connection is defined between the control volume and a pressure sink, wherein one connection from the charging connection and the discharging connection comprises a smallest cross-sectional flow area which, together with a gas pressure of the gas pressure source, determines the delay time of the safety device.
The present disclosure also relates to a corresponding method for operating a drive-in tool.

Claims

1. A method of operating a drive-in tool including a workpiece contact element, a trigger, a control volume, a gas pressure source connection, and a pressure sink, said method comprising: charging the control volume with air pressure via a pneumatic charging connection between the control volume and the gas pressure source connection; and after the workpiece contact element is actuated via engagement with a workpiece and after the trigger is actuated: disconnecting the pneumatic charging connection between the control volume and the gas pressure source connection, causing the drive-in tool to be in a trip-ready state, discharging the air pressure in the control volume via a pneumatic discharging connection between the control volume and a pressure sink, and after the gas pressure in the control volume falls below a gas pressure threshold, causing the drive-in tool to switch from the trip-ready state to a secured state.

2. The method of claim 1, wherein disconnecting the pneumatic charging connection between the control volume and the gas pressure source connection includes moving an activation element.

3. The method of claim 2, which includes a first pneumatic line that extends from the activation element toward the gas pressure source connection and a second pneumatic line that extends from the activation element toward the pressure sink, and which includes controlling an amount of time that the drive-in tool is in the trip-ready state via only one of the first pneumatic line and the second pneumatic line.

4. The method of claim 1, wherein disconnecting the pneumatic charging connection between the control volume and the gas pressure source connection includes moving an activation element coupled to the trigger.

5. The method of claim 1, wherein disconnecting the pneumatic charging connection between the control volume and the gas pressure source connection includes moving an activation element coupled to the workpiece contact element.

6. The method of claim 1, wherein disconnecting the pneumatic charging connection between the control volume and the gas pressure source connection includes moving an activation element coupled to the trigger and the workpiece contact element.

7. The method of claim 1, wherein discharging the air pressure in the control volume includes moving an activation element.

8. The method of claim 1, wherein discharging the air pressure in the control volume includes moving an activation element coupled to the trigger.

9. The method of claim 1, wherein discharging the air pressure in the control volume includes moving an activation element coupled to the workpiece contact element.

10. The method of claim 1, wherein discharging the air pressure in the control volume includes moving an activation element coupled to the trigger and the workpiece contact element.

11. The method of claim 1, which includes controlling a rate of discharge of the air pressure from the control volume via one or more cross-sectional gas flow areas of the pneumatic discharging connection.

12. The method of claim 1, which includes controlling an amount of time the drive-in tool is in the trip-ready based on a volume of the control volume.

13. The method of claim 1, which includes, responsive to an activation element being in a first position, disconnecting the pneumatic discharging connection between the control volume and the pressure sink, and causing the pneumatic charging connection between the control volume and the gas pressure source connection.

14. The method of claim 13, which includes, responsive to the activation element being in a different second position, disconnecting the pneumatic charging connection between the control volume and the gas pressure source connection, and causing the pneumatic discharging connection between the control volume and the pressure sink.

15. The method of claim 1, which includes, responsive to an activation element being in a first position, disconnecting the pneumatic discharging connection between the control volume and the pressure sink, causing the pneumatic charging connection between the control volume and the gas pressure source connection, and causing the drive-in tool to be in the secured state.

16. The method of claim 15, which includes, responsive to the activation element being in a different second position, disconnecting the pneumatic charging connection between the control volume and the gas pressure source connection, causing the pneumatic discharging connection between the control volume and the pressure sink, and causing the drive-in tool to switch from the secured state to the trip-ready state.

17. The method of claim 1, which includes providing the pneumatic charging connection between the control volume and the gas pressure source connection through an activation element.

18. The method of claim 1, which includes providing the pneumatic discharging connection between the control volume and the pressure sink extending through a movable activation element.

19. The method of claim 1, which includes providing the pneumatic charging connection between the control volume and the gas pressure source connection extending through a movable activation element when the activation element is in a first position and providing the pneumatic discharging connection between the control volume and the pressure sink extending through the activation element when the activation element is in a different second position.

20. The method of claim 1, which includes providing the pneumatic charging connection between the control volume and the gas pressure source connection extending through a movable activation element.

Description

[0099] The present disclosure is now to be further illustrated as an example by way of drawings, in which:

[0100] FIGS. 1a and 1b show a schematic diagram of a tool according to one example embodiment of the present disclosure,

[0101] FIG. 2 to FIG. 8 show sectional representations of an even more preferred example embodiment of a tool based on FIGS. 1a and 1b in different states,

[0102] FIG. 9 shows a flow diagram of the use of a further preferred example embodiment of a tool of the present disclosure based on the preceding figures in different states which are shown again in part in the preceding figures,

[0103] FIG. 10 to FIG. 12 show, building on the preceding figures, a variant example embodiment of the present disclosure in which the activation element is also displaceable by way of the workpiece contact element,

[0104] FIG. 13 shows a flow diagram for said variant of FIG. 10 to FIG. 12,

[0105] FIG. 14 to FIG. 20 show a further variant of the present disclosure shown in FIG. 1 to FIG. 9, wherein the control volume 15 is realized by the trip valve 20,

[0106] FIGS. 21a to 24b show different arrangements according to the present disclosure of the smallest cross sectional flow area which defines the delay time of the safety device.

[0107] FIGS. 1a and 1b show a schematic diagram of a tool 1 according to one example embodiment of the present disclosure for driving fasteners such as fastener 90 into a workpiece such as workpiece 91. The tool 1 comprises: [0108] an actuator unit 3, by way of which the fasteners 90 are drivable into the workpiece 91 in drive-in cycles, [0109] a trip arrangement 5, by way of which the drive-in cycles of the actuator unit 3 are trippable, wherein the trip arrangement 5 comprises a trigger element 6 which is manually operable and comprises an idle state 600 (shown in FIG. 1a) and a pressed state 601 (shown in FIG. 1b), wherein the trip arrangement 5 additionally comprises a workpiece contact element 7 which is actuatable by placing the drive-in tool 1 onto the workpiece 91, [0110] a gas pressure source connection 23 to which a gas pressure source is connectable, [0111] a safety device 8 which is coupled with the trigger element 6 and is set up to bring about a transfer of the drive-in tool 1 from a trip-ready state into a secured state after expiry of a delay time which proceeds from an activation of the safety device 8, [0112] wherein the safety device 8 comprises a control volume 15, [0113] wherein the safety device 8 comprises an activation element 33 which is changeable between a first and a second position by way of the trigger element 6.

[0114] In the first position of the activation element 33, a pneumatic connection is defined between the control volume 15 and the gas pressure source connection 23, which is hereafter referred to as charging connection 27.1. In the second position of the activation element 33 a pneumatic connection is defined between the control volume 15 and a pressure sink 40, which is hereafter referred to as discharging connection 33.1. One connection from the charging connection 27.1 and the discharging connection 33.1, here the discharging connection 33.1, comprises a smallest cross-sectional flow area 33.8 which, together with a gas pressure of the gas pressure source, determines the delay time of the safety device.

[0115] In this case, the safety device 8 of the tool 1 functions as follows. In FIG. 1a, the control volume 15 is charged by way of the charging connection 27.1. If the user, proceeding from FIG. 1a, presses the trigger 6, the activation element 33 is displaced such that the charging connection 27.1 is disconnected and the discharging connection 33.1 is established (FIG. 1b). As a result of the small cross sectional flow area of the discharging connection 33.1, the control volume 15 is discharged slowly, i.e., at the determined delay time. Dependent on the pressure in the control volume 15, the tool 1 is then moved into a trip-ready state or a secured state.

[0116] These figures additionally show one preferred development, according to which the correspondingly other connection from the charging connection 27.1 and the discharging connection 33.1, i.e., here the charging connection 27.1, comprises a larger smallest cross sectional flow area than the one connection from the charging connection 27.1 and the discharging connection 33.1, i.e., here the discharging connection 33.1, as a result of which the control volume 15 is able to be charged very rapidly.

[0117] In addition, one preferred development is illustrated, according to which the tool 1 comprises a pneumatic line which is both part of the charging connection 27.1 and part of the discharging connection 33.1 and which extends from the activation element 33 toward the control volume 15. In this case, the tool 1 additionally comprises two lines which are separate from one another, wherein one of the lines which are separate from one another is part of the charging connection 27.1 and extends from the activation element 33 toward the gas pressure source connection 23, and the other of the lines which are separate from one another is part of the discharging connection 33.1 and extends from the activation element 33 toward the pressure sink 40. The smallest cross sectional flow area 33.8, which, together with the gas pressure, determines the delay time of the safety device 8, is present in precisely one of the lines which are separate from one another, here in the line which extends from the activation element 33 toward the pressure sink 40. The rapid charging and slow discharging of the control volume 15 is realized structurally in a very advantageous manner as a result.

[0118] Further preferred developments are provided herein, namely that the safety device 8 is set up to transfer the tool 1 into the secured state if a pressure threshold in the control volume is fallen below and that the charging connection 27.1 is present when the trigger element 6 is in its idle state 600.

[0119] FIG. 2 to FIG. 8 show sectional representations of an even more preferred embodiment of a tool 1 based on FIGS. 1a and 1b in different states. It has the features described and shown in FIG. 1a and FIG. 1b.

[0120] Provided herein additionally are the following preferred features which are also usually present in the case of a compressed air drive-in tool, but are not absolutely necessary and which also interact well with various features of the present disclosure in an alternative form: [0121] the trigger element 6 is a trigger lever which is pivotably mounted on a trigger element axis 6a; [0122] the actuator unit 3 comprises an operating cylinder 10 in which is guided an operating piston 11 which moves a drive-in punch 9; and [0123] a drive volume 13 is present on the side of the operating piston 11 on the other side of the drive-in punch 9.

[0124] FIGS. 2 and 3 show the tool 1 when the compressed air is not connected, the standby element 27 is situated in the safety position. FIG. 4 shows the tool 1 with the compressed air connected, neither the trigger element 6 nor the workpiece contact element 7 being actuated, and wherein the standby element 27 is situated in the standby position. FIG. 5 shows the tool 1 with the trigger element 6 pressed and with the standby element 27 still in the standby position. FIG. 6 shows the tool 1 after the predetermined time has elapsed and the tool 1 has been transferred into the secured state, wherein the standby element 27 is now situated in the safety position. FIG. 7 shows the tool 1 in the state of tripping a drive-in operation, wherein the standby element 27 in this case is in the standby position. FIG. 8 shows the tool with the trigger element 6 and the workpiece contact element 7 pressed, it being situated in the secured state, and wherein the standby element 27 is situated in the safety position, and consequently wherein no drive-in operation is tripped.

[0125] The activation element 33 is resettable pneumatically in the position from its first and second position in which the activation element 33 is situated in the idle state 600 of the trigger element 6. The activation element 33 comprises a positive surface difference between surfaces which are acted upon by gas from the gas pressure source connection less surfaces which are connected to the pressure sink 40.

[0126] The safety device 8 comprises a standby element 27 which is displaceable pneumatically into a safety position and a standby position. The tool 1 is situated in the secured state (shown in FIGS. 2, 3, 6, and 8) when the standby element 27 is situated in the safety position, and it is situated in the trip-ready state 100 (shown in FIGS. 4, 5, and 7) when the standby element 27 is situated in the standby position. The standby element 27 is arranged between the control volume 15 and the gas pressure source 23 and the charging connection 27.1 is guided through at least two openings in the standby element 27 (FIG. 4). The standby element 27 comprises a first surface region with a first surface area A1 which can be acted upon by gas pressure from the control volume 15 when the trigger element 6 is in its pressed state 601. It comprises a second surface region with a second surface area A2 which can be acted upon with gas from the gas pressure source when trigger element 6 is in its pressed state 601 and when trigger element 6 is in its idle state 600. The first and the second surface regions are set up to direct opposing displacement forces onto the standby element 27 when acted upon with pressure. They comprise opposing components of surface normals for this purpose. The first and second surface regions are situated in a common pneumatic volume when the activation element 33 is situated in the first position (to the left, or in the position closer to the trigger element) and are situated in two separate volumes when the activation element 33 is situated in the second position (to the right, or further away from the trigger element). The first surface area A1 is greater than the second surface area A2. The standby element 27 is realized as a tube piece which is open at both end faces and comprises a central through channel 27.3. The tube piece comprises, along with the through channel 27.3, an axial secondary channel 27.4 which comprises an opening which faces the through channel 27.3 and one which is at an axial spacing therefrom and faces the outside surrounding area of the tube piece. The secondary channel 27.4 is part of the charging connection 27.1 (FIG. 4). The activation element 33 is guided movably on the standby element 27 and relative to the standby element 27. The activation element 33 and the standby element 27 are nested in one another and are concentric. Outer sealing rings 33.2, 33.3, 33.4, 33.5, 33.6, and 33.7 of the activation element 33 abut directly against the inside contour of the standby element 27. The activation element 33 is also realized as a tube piece. The discharging connection 33.1 extends through two openings in the activation element 33, present in a lateral surface of the activation element 33.1 (FIG. 5). The discharging connection 33.1 is defined in the activation position (second position, on the right) by the activation element 33.

[0127] The tool 1 comprises a main trip valve 12 and a trip element 21 which is set up to interrupt a pneumatic trip connection 21.1 (FIG. 5) from the gas pressure source connection 23 to the main trip valve 12 when the standby element 27 is in the standby position. By way of the standby element 27, a pneumatic secondary line 27.2 is provided between the main trip valve 12 and the gas pressure source connection 23 by bypassing the trip element 21 when the standby element 27 is in the safety position (FIG. 6) or when the activation element 33 is in the first position, to the left (FIG. 4). The activation element 33 defines part of the trip connection 21.1 from the gas pressure source connection 23 to the main trip valve 12 (FIG. 5). The trip element 21 is guided movably on the activation element 33 and relative to the activation element 33. The activation element 33 and the trip element 21 are nested in one another. The trip element 21 is set up here to define a pneumatic trip discharging connection 21.2 between the main trip valve 12 and the pressure sink 40.

[0128] The trigger element 6 comprises a coupling element 26 which can be acted upon by the workpiece contact element 7 in each position of the trip element 21 and which couples the workpiece contact element 7 and the trigger element 6 mechanically with the trip element 21.

[0129] In addition, the following advantageous, optional specifications are shown here: [0130] in order to enable continuous contact tripping (trigger element 6 held in the pressed state, workpiece contact element 7 actuated repeatedly at short intervals, shorter than the predetermined time), the operating cylinder 10 comprises a ventilation arrangement 18 produced from at least one, here several openings 18a in the lateral surface which are covered radially outward (with reference to the operating cylinder 10) by way of a resilient sealing ring 18b which acts as a one-way valve; the ventilation arrangement 18 is arranged in a portion 14 of the operating cylinder 10 which is located on the other side of the drive volume 13 in the idle position with reference to the operating piston 11; compressed air is directed into the control volume in this way via the openings 18a as a result of a drive-in operation; the countdown of the safety device 8 is reset in this way even when the trigger element 6 is kept continuously pressed; [0131] elements (in particular 27, 33, and 21) of the safety device 8 are combined as a trip valve 20 of the trip arrangement 5, the trip valve 20 being arranged in a preferred manner in the handle portion 24 of the tool 1—in this respect the trip valve 20 itself can also be viewed as part of the safety device 8; the trip valve comprises a housing 20.1 in which the standby element 27 is displaceably mounted with sealing elements, here sealing rings; the activation element 33 and the trip element 21 are additionally accommodated in the housing 20.1; a pneumatic line 12a leads from the trip valve 20 to the main trip valve 12 (only the start of said line can be seen here at the trip valve 20, the rest of the line 12a is concealed); a valve inlet 22 is present in the housing 20.1 on the gas source side and a valve inlet 30 on the control volume side; between the valve inlet 30 on the control volume side and the control volume 15 there is a ventilation/venting line, by way of which the control volume 15 is able to be ventilated or vented by way of the trip valve 20; [0132] a trip element spring 21a pre-stresses the trip element 21 into its idle position (to the left).

[0133] FIG. 9 shows a flow diagram of the use of the further preferred embodiment of a tool based on the preceding figures in different states which are shown in part in the preceding figures (cross-referenced by Roman numerals). In each case states are shown in circles and events in squares.

[0134] In state I, the tool 1 is not connected to the gas pressure source. Consequently, the tool is situated in the secured state 101. The trigger element 6 is situated in the idle state 600 and the workpiece contact element 7 is in the non-actuated state 700. The safety device 8 is not active, i.e., a time counter is not running. In said state, the standby element 27 can be situated either in the safety position (left position) or in the standby position (right position).

[0135] In the state II, the tool 1 is then in use by connecting 230 it to the gas pressure source, as a result of which the instrument assumes the trip-ready state 100. In this case, the standby element 27 (unless it was not already situated there in state I) is moved into its standby position. This is brought about by the surface difference between the surface regions A1 and A2 which, in said state, are both acted upon by the pressure from the gas pressure source. The control volume 15 is “charged” with gas pressure via the charging connection 27.1. In addition, in said state there is a secondary line 27.2 which bridges the trip element 21. The secondary line 27.2 is consequently a connection, which cannot be interrupted by the trip element 21, from the gas pressure source connection 23 to the main trip valve 12.

[0136] Proceeding from said state II, by actuating 710 the workpiece contact element 7 (e.g., placing and pressing the tool tip onto a workpiece) a next sequence state can be achieved (on the left, second line) where the workpiece contact element 7 is then situated in its actuated state 701.

[0137] Proceeding from said state, by actuating 610 the trigger element 6, the state V is achieved or by raising 720 the workpiece contact element 7 state II is resumed.

[0138] In the state V, a drive-in cycle is tripped (indicated by the double border). The trigger element 6 is situated in the pressed state 601 and the workpiece contact element 7 in the actuated state 701. The trip element 21 is in its trip position, which is achieved by way of the coupling element 26. By both the trigger element 6 and the workpiece contact element 7 in said state V being situated in their actuated or pressed states in each case, the trip connection 21.1 is established from the main trip valve 12 to the pressure sink 40 such that the main trip valve 12 is activated and the drive-in operation is carried out. In this case, the drive volume 13 is acted upon with the gas pressure from the gas pressure source such that the operating piston is moved in the direction of the tool tip (to the left). It passes the ventilation arrangement 18, as a result of which the control volume 15 is also acted upon with gas pressure from the gas pressure source via the openings 18a. From said state V, the previous state is achieved by releasing 620 the trigger element 6 (on the left, second line) or the state III is achieved by raising 720 the workpiece contact element 7. The raising 720 simultaneously initiates an activation 810 of the safety device 8, as a result of which a countdown starts for displacing the tool 1 into the secured state 101. For by way of the raising 720, the operating piston 11 is moved into its idle position again such that the control volume 15 is then no longer able to be charged by way of the ventilation arrangement 18—the resilient ring, in this case, prevents discharging in the direction of the operating cylinder 10. As the trigger element 6 is pressed 601, and consequently the discharging connection 33.1 is established, the pressure in the control volume 15 is gradually reduced, i.e., the countdown is running and the safety device 8 is activated.

[0139] In the state III, by actuating 610 the trigger element 6 the state II is additionally achieved, as a result of which the safety device 8 is also activated and consequently a countdown to displace the tool 1 into the secured state 101 is started. The control volume 15, in this case, has been charged by the charging connection 27.1 in the state II and is then slowly discharged by way of the discharging connection 33.1.

[0140] In the state III, the control volume 15 is separated from the gas pressure source (whilst, for example, in state II a connection has existed between the same via the charging connection 27.1) and air escapes via the discharging connection 33.1 such that the standby element 27 moves abruptly in the direction of the safety position once a certain time has elapsed.

[0141] If the trigger element 6 is then released 620, state II is resumed. In this case, the control volume 15 is reconnected to the gas pressure of the gas pressure source and the charging connection 27.1 and the discharging connection 33.1 are separated. The standby element 27 is displaced back into the standby position and remains there.

[0142] If, on the other hand, the workpiece contact element 7 is actuated 710, the state V is resumed and a drive-in cycle takes place. The actuation 710 causes the trip element 20 to be displaced into the trip position (right position) by way of the coupling element 26 such that the trip connection 21.2 is re-established.

[0143] If, in contrast, state III is maintained longer than the predetermined time, i.e., an elapsing 820 of the predetermined time is expected, the state IV is achieved.

[0144] In the state IV, the standby element 27 has arrived in the safety position (left position). The standby element 27 in said position allows for a secondary line 27.2 which connects the main trip valve 12 to the gas pressure of the gas pressure source such that, irrespective in which position the trip element 21 or the activation element 33 are situated, it is not possible to interrupt said connection. An interruption would be possible, however, in order to trip a drive-in operation. Consequently, tripping is impossible and consequently the tool 1 is situated in the secured position 101. Activation 710 of the workpiece contact element 7, which leads into the state VI and displaces the trip element into its trip position, cannot produce any tripping either as the secondary line 27.2 is defined by the standby element 27. In order to get out of the secured state 101 again, the user has to release 620 the trigger element 6. Thus the state IV is left and the state II is resumed or the state VI is left and the state which is shown in the second line on the left is resumed. By releasing 620 the trigger 6, the control volume 15 is reconnected to the gas pressure source and the standby element 27 is displaced into the standby position, as the activation element 33 is displaced pneumatically back again into the left position when the trigger 6 is released and then the charging connection 27.1 is re-established.

[0145] FIG. 10 to FIG. 12 show, building on the preceding figures, a variant in which the activation element 33 is also displaceable by way of the workpiece contact element 7. The workpiece contact element 7 is coupled mechanically with the activation element 33 in such a manner that the workpiece contact element 7 is able to press the activation element 33 into the activation position (right position); said state is shown in FIGS. 11 and 12, the standby element 27 being situated in the standby position in FIG. 11 and in the safety position in FIG. 12. Said additional mechanical coupling with the activation element 33 is indicated here as an example and in a rough manner by way of an angled region of the workpiece contact element 7. The workpiece contact element 7 is set up in the same way as previously to press the trip element 21 by way of the coupling element 26. Only if both elements from the trigger element 6 and the workpiece contact element 7 are not actuated or are in the idle state is the activation element 33 able to move out of the activation position.

[0146] FIG. 13 shows a flow diagram for said variant in FIGS. 10 to 12, once again states being referenced with Roman numerals—the states II—VI, in this case, can be taken from FIGS. 2 to 8, just the changed mechanical coupling between the activation element 33 and the workpiece contact element 7 providing a difference, the state otherwise, however, being the same. The sequence builds on the sequence shown in FIG. 9; in contrast to this, the safety device 8 is now already activated by way of actuating 710 the workpiece contact element 7 such that it is now situated in the activated state 801 in the state VII, for the activation element 33 is displaced by the workpiece contact element 7 into the activation position, left position, such that the discharging connection 33.1 is established. Consequently, it is possible for the predetermined time to run out 820 already from state VII and the tool is transferred into the secured state 101, which leads overall to the state VIII which is new compared to FIG. 9, as now a secured state 101 can also be achieved when the trigger element 6 is situated in the non-pressed state 600. Another difference is that it is now no longer possible proceeding from the state VI by releasing 620 the trigger element 6 for the tool to be transferred back into a trip-ready state 100, for, as a general rule, it is only possible to transfer into the trip-ready state 100 when both the trigger element 6 and the workpiece contact element 7 are moved into the non-actuated or non-pressed state.

[0147] FIG. 14 to FIG. 20 show a variant according to the present disclosure of the tool according to the present disclosure shown in FIG. 1 to FIG. 9, in contrast thereto the control volume 15 being realized by the trip valve 20. Otherwise the states marked in FIG. 14 to FIG. 19 with Roman numerals also correspond to the states in FIGS. 2 to 9 and also the flow diagram in FIG. 9 retains its validity. In addition, it is possible to provide the modification according to FIGS. 10 to 12 also for said variant, i.e., the activation element 33 is also displaceable just by way of the workpiece contact element 7 and consequently the flow diagram from FIG. 13 is to be used.

[0148] In comparison with preceding variants there are the following differences: [0149] the control volume 15 is reduced to the region also already present previously inside the trip valve housing 20.1 which adjoins the surface region A1. No separate volume adjoining the drive-in piston 10 is necessary and consequently no special valve inlet 30 on the control volume side and no ventilation arrangement 18 arranged on the operating cylinder 10 either. As these are not present, as a rule, in the case of existing former tool housings, on account of said trip valve 20 former tool housings are easily able to be retrofitted with the safety device 8. [0150] The trip valve 20, when the tool 1 is situated in the trip-ready state 100 and the trigger element 6 is situated in the pressed state 601 and at the same time the workpiece contact element 7 is actuated (see FIG. 18, state V), then defines a pneumatic connection. Said connection is a further charging connection 27.3 between the control volume 15 and the gas pressure source connection 23, as the discharging connection 33.1 comprises the smallest cross sectional flow area 33.8. The control volume 15 is filled with pressure again by way of said charging connection 27.3, as a result of which the elapsed delay time is reset. I.e., each time a drive-in operation is tripped (corresponds to state V) the safety device 8 is reset again in this way directly by way of the trip valve 20. [0151] The discharging connection 33.1, which also comprises the smallest cross sectional flow area 33.8, is present both in the first position of the activation element 33 and in the second position of the activation element 33. In addition, the smallest cross sectional flow area 33.8 is variable by way of an adjusting needle 34.1 which forms a needle valve 34 and the cross sectional flow area is consequently very finely adjustable. The needle valve 34 is shown in detail in FIG. 20. The adjusting needle 34.2 is arranged on an adjusting screw 34.1. The adjusting screw 34.1 is screwed into a suitable thread of the housing 20.1 such that the adjusting needle 34.2 projects into an opening of the housing 20.1, the cross sectional flow area of which is consequently variable as a result of rotating the adjusting screw 34.1. A preferred anti-twist ring 34.3 protects the adjusting screw 34.3 from unwanted rotation. After the needle valve 34 in a groove, the gas then escapes past a dowel pin 28, by way of which the trip valve housing is secured in the tool housing, to the atmosphere (pressure sink 40)—this is only indicated here as in said drawing plane the dowel pin 28 fills out the groove for the dowel pin in a substantial manner, which, however, is not so in another drawing plane, as a result of which sufficient space is then provided there for the air flow.

[0152] FIGS. 21a to 24b show schematic diagrams of arrangements according to the present disclosure of the smallest cross sectional flow area which defines the delay time of the safety device. These are in each case pairs of figures (a and b), in the respective figure b the activation element 33 being shown in the activation position, i.e., in the position in which the delay time starts to run down. The other position of the activation element 33 is then shown in the respective figure a.

[0153] The smallest cross sectional flow area 33.8, which, together with the gas pressure, determines the delay time of the safety device 8, is arranged in precisely one of the following pneumatic connections: [0154] in a pneumatic connection between the activation element 33 and the gas pressure source connection 23—as is shown in FIGS. 22a/b; [0155] in a pneumatic connection between the activation element 33 and the pressure sink 40—as is shown in FIGS. 21a/b and FIGS. 1 to 13; [0156] in a pneumatic connection which exists in both the first position and the second position of the activation element 33 between the control volume 15 and the gas pressure source connection 23—as is shown in FIGS. 23a/b; [0157] in a pneumatic connection which exists in both the first position and the second position of the activation element 33 between the control volume 15 and the pressure sink 40—as is shown in FIGS. 24a/b and FIGS. 14 to 20.

[0158] As a result, by way of the said arrangements in which in each case the smallest cross sectional flow area 33.8 is not located in a region which is utilized in a line portion which is common to a charging connection 27.1 and a discharging connection 33.1, rapid resetting of the pressure in the control volume 15 is made possible by releasing the trigger element 6 such that the tool 1 is also rapidly transferable (quicker than the delay time) from the secured state 101 into the standby state 100 again. FIGS. 22a/b and 23a/b show configurations where the safety device 8 transfers the tool 1 into the secured state 101 when a pressure threshold in the control volume 15 is exceeded, whilst FIGS. 21a/b and FIGS. 24a/b along with FIGS. 1 to 20 show configurations where the safety device 8 transfers the tool 1 into the secured state 101 when a pressure threshold in the control volume 15 is fallen below.

LIST OF REFERENCES

[0159] 1 Drive-in tool [0160] 3 Actuator unit [0161] 5 Trip arrangement [0162] 6 Trigger element [0163] 6a Trigger element axis [0164] 7 Workpiece contact element [0165] 8 Safety device [0166] 9 Drive-in punch [0167] 10 Operating cylinder [0168] 11 Operating piston [0169] 12 Main trip valve [0170] 12a Line to the main trip valve [0171] 13 Drive volume [0172] 14 The portion of the operating cylinder located on the other side of the drive volume with reference to the operating piston [0173] 15 Control volume [0174] 18 Ventilation arrangement [0175] 18a Openings [0176] 18b Resilient ring [0177] 19 Ventilation/venting line [0178] 20 Trip valve [0179] 20.1 Housing [0180] 21 Trip element [0181] 21.1 Trip connection [0182] 21.2 Trip discharging connection [0183] 21a Trip element spring [0184] 22 Valve inlet on the gas source side [0185] 23 Gas pressure source connection [0186] 24 Handle portion [0187] 26 Coupling element [0188] 27 Standby element [0189] 27.1 Charging connection [0190] 27.2 Secondary line [0191] 27.3 Central through channel [0192] 27.4 Axial secondary channel [0193] 27.5 Further charging connection [0194] 28 Dowel pin [0195] 30 Valve inlet on the control volume side [0196] 33 Activation element [0197] 33.1 Discharging connection [0198] 33.2, 33.3, 33.4, 33.5, 33.6, 33.7 Sealing rings of the activation element [0199] 33.8 Smallest cross sectional flow area which, together with the gas pressure of the gas pressure source, determines the delay time of the safety device [0200] 34 Needle valve [0201] 34.1 Adjusting screw [0202] 34.2 Adjusting needle [0203] 34.3 Anti-twist ring [0204] 34.4 Needle opening [0205] 40 Pressure sink [0206] 90 Fasteners [0207] 91 Workpiece [0208] 100 Trip-ready state of the tool [0209] 101 Secured state of the tool [0210] 230 Connect to an energy source [0211] 600 Idle state of the trigger element [0212] 601 Pressed state of the trigger element [0213] 610 Actuate the trigger element from the idle state to the pressed state [0214] 620 Actuate the trigger element from the pressed state to the idle state [0215] 700 Non-actuated state of the workpiece contact element [0216] 701 Actuated state of the workpiece contact element [0217] 710 Actuate the workpiece contact element [0218] 720 Raise the workpiece contact element from the workpiece [0219] 800 Inactive safety device [0220] 801 Active safety device [0221] 810 Activate the safety device [0222] 820 Automatic elapsing of the predetermined time [0223] A1 First surface content [0224] A2 Second surface content