Pneumatic nailer with a safety device

Abstract

A pneumatic nailer is provided comprising a working piston which is connected to a driving plunger for driving in a fastening means and which is subject to compressed air when a driving-in process is triggered, The nailer also includes a triggering device for initiating a driving-in process, a safety device configured to switch the nailer from a trigger-ready state to a locked state a control valve to control the pressure inside of the control chamber which includes a control valve member which is moveable along an adjustment path and a damper coupled to the control valve member.

Claims

1. A pneumatic nailer comprising: a working piston configured for being connected to a driving plunger for driving in a fastener, wherein the working piston is subject to compressed air when a driving-in process is triggered; a safety device configured to be controlled by pressure in a control chamber, the safety device configured to switch the pneumatic nailer from a trigger-ready state to a locked state; a control valve configured to control the pressure inside the control chamber, the control valve comprising a control valve member movable along an adjustment path; and a damper coupled to the control valve member.

2. The pneumatic nailer as recited in claim 1, wherein the damper is coupled to the control valve member such that the damper slows down movement of the control valve member along at least one section of the adjustment path.

3. The pneumatic nailer as recited in claim 1, further comprising a triggering device that comprises a contact feeler that is configured to move the control valve member to a fully actuated position when the pneumatic nailer is placed against a workpiece.

4. The pneumatic nailer as recited in claim 1, wherein the control valve member comprises a first switching point at which time the control valve deaerates or aerates the control chamber, and wherein the damper is coupled with the control valve member so that, after removing the pneumatic nailer from the from a workpiece, the control valve member reaches a fully actuated position starting from the first switching point after expiration of a specified period of time.

5. The pneumatic nailer as recited in claim 1, wherein the pneumatic nailer comprises a main control line which must be aerated when a drive-in process is triggered, and wherein the control valve member comprises a second switching point at which time the control valve deaerates the main control line.

6. The pneumatic nailer as recited in claim 1, wherein the pneumatic nailer comprises a main control line which must be deaerated when a drive-in process is triggered, and wherein the control valve member comprises a second switching point at which time the control valve aerates the main control line.

7. The pneumatic nailer as recited in claim 1, wherein the damper is configured to be coupled to the control valve member such that a movement of the control valve member from a fully actuated position to a second switching point is not damped.

8. The pneumatic nailer as recited in claim 1, wherein the damper comprises a slot hole for relieving pressure in the damper, so that a relative movement between two components of the damper are not are not restricted by the damper for a possible range of motion of the damper.

9. The pneumatic nailer as recited in claim 1, wherein a dampening effect by the damper is limited to one of two possible directions of motion of the damper.

10. The pneumatic nailer as recited in claim 1, wherein the damper comprises two elements movable relative to one another, whose relative motion is dampened by the damper, wherein one of the elements is fixed and/or hinged to a part of the pneumatic nailer which is fixed to a housing and the other element is fixed and/or hinged to the: (i) contact feeler, (ii) control valve member, (iii) a force transmission device configured to transmit a force from the contact feeler to the control valve member.

11. The pneumatic nailer as recited in claim 1, wherein the damper is one of a linear damper and a rotary damper.

12. The pneumatic nailer as recited in claim 1, wherein the damper is one of a fluid damper and a friction damper.

13. The pneumatic nailer as recited in claim 3, wherein the safety device comprises a safety actuator which is switchable between an actuatable position, wherein the triggering device can initiate a driving-in process, and a safe position, wherein actuating the triggering device will not initiate a driving-in process since the pressure in the control valve exerts a force on the safety actuator.

14. The pneumatic nailer as recited in claim 13, wherein the safety actuator is moved from an actuatable position to the safety position when the pressure inside the control valve exceeds a predetermined pressure threshold.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) The disclosure is described in more detail hereinafter with reference to an exemplary embodiment shown in seven figures, in which:

(2) FIG. 1 depict a pneumatic nailer according to the disclosure in a schematic cross-sectional view; and

(3) FIGS. 2 to 7 depict enlarged cross-sectional views of various operational views of the pneumatic nailer.

DETAILED DESCRIPTION OF THE DISCLOSURE

(4) The pneumatic nailer, of which only a section is shown in FIG. 1, has a pneumatic connection and a working cylinder in which a working piston connected to a driving ram is slidably guided. The working cylinder is closed at the top by a main valve which is actuated by a pilot valve. As far as now and in the following the directions above and below are used, these refer to the normal working position of the pneumatic nailer, where the pneumatic nailer is placed on a workpiece with a horizontal surface. A magazine is used to hold a supply of fasteners, especially nails or staples, and ends at the front of a mouth tool into which individual fasteners are inserted. These are then driven into a workpiece by the driving ram when compressed air is applied to the working piston, controlled via the main valve and the pilot valve. These elements of the pneumatic nailer essentially correspond to the state of the art and can, for example, be designed as described in detail in EP 3 257 633 B1 using FIGS. 1 and 2.

(5) FIG. 1, on the other hand, shows a section of a housing 10, which forms a handle 12 which is also partially depicted. A contact feeler 14 is slidably guided in a vertical direction on the housing 10, whereby a lower end of the contact feeler 14, not shown in FIG. 1, protrudes in its lower position above the mouth tool in a manner known from the state of the art. In this lower position, which is shown in FIG. 1, the pneumatic nailer is not applied to a workpiece. At its upper end, the probe 14 has a slot hole 16 with a pin 18 attached to the housing 10. From the position of this pin 18 in the slot hole 16, it is clearly visible in all figures in which position the contact feeler 14 is currently located.

(6) A spring 20 is arranged between the housing 10 and the contact feeler 14, which presses the contact feeler 14 downwards. In addition, a damper 22 is arranged between housing 10 and contact feeler 14, which in the example shown has a cylindrical damper housing 24 in which a damper ram 26 is displaceably guided. The damper ram 26 protrudes from the lower end of the damper housing 24 and is attached at its free end to the contact feeler 14. At the opposite, upper end, the damper 22 has a mounting section 28, which is firmly connected to the damper housing 24. The upper free end of this mounting section 28 is hinged with a horizontally arranged pin 30 to a slot hole 32 formed in the housing 10. The length of the slot hole 32 is smaller than the length of the slot hole 16, in the shown example about half as long.

(7) The damper 22 is designed so that it dampens a movement of the damper ram 26 downwards, i.e. out of the damper housing 24, but not a movement in the opposite direction, i.e. into the damper housing 24. This means that when the pneumatic nailer is applied to a workpiece, the contact feeler 14 can be moved upwards essentially uninfluenced by the damper 22. After removing the pneumatic nailer from a workpiece, the combined effect of the spring 20 and the damper 22 determines the speed at which the contact feeler 14 moves downwards again when the pin 30 rests against the lower end of the slot hole 32 and has to be pulled out of the damper housing 24 for the further downward movement of the damper ram 26.

(8) A trigger device of the pneumatic nailer comprises a trigger 36 pivotally mounted at its front end about a horizontal axis 34. The trigger 36 has an actuating surface 38 for actuating a valve pin 40 of a trigger valve 42. Furthermore, the triggering device comprises a force transmission element in the form of a lever 44 which is pivotally mounted at its rear end about an axis 46 arranged horizontally and fixed to the housing. The free end 48 of the lever 44 rests against an upper surface 50 of the contact feeler 14. An actuating surface 52 arranged on the upper side of the lever 44 serves to actuate a control valve member 54 in the form of a valve pin of a control valve 56. As will be explained in more detail in the other figures, proper actuation of the contact feeler 14 and trigger 36 triggers a driving-in process by pressurizing a main control line 58 via the trigger valve 42 and the control valve 56 with compressed air from a aerated housing interior 60.

(9) FIG. 2 shows an enlarged section from FIG. 1. The contact feeler 14 is still in its lower end position and the trigger 36 is not actuated. The control valve member 54, which moves along an adjustment path, is also in a lower end position, which corresponds to a completely unactuated position of the control valve 56. The valve pin 40 of the trigger valve 42 is also not actuated. It has a lower O-ring 62 which is not located in the seal and an upper O-ring 64 which is located in the seal.

(10) In this position, a transverse hole 66, located in a sleeve 68 of the trigger valve 42, is connected to outside air via an annular gap 70 and past the lower O-ring 62. The line 72 between trigger valve 42 and control valve 56, which is connected to the transverse hole 66, is therefore deaerated. At the same time, the aerated housing interior 60 is shut off from the transverse hole 66 and the line 72 by the upper O-ring 64 located in the seal.

(11) The control valve member 54 is movably guided in a two-piece sleeve fixed to the housing with an inner sleeve part 74 and an outer sleeve part 76. The outer sleeve part 76 is surrounded by a safety actuator 78, which is also sleeve-shaped. The safety actuator 78 is mounted in the housing 10 so that it can be displaced in the vertical direction. It is pressed by a spring 80 into its upper end position shown in FIG. 2, which corresponds to a trigger-ready state of the pneumatic nailer.

(12) The safety actuator 54 has four O-rings: A first O-ring 82 seals the inner sleeve part 74 from the control valve 54 in any position. Between a second O-ring 84 and a third O-ring 86, both of which are not in the seal, ends a transverse hole 88 in the control valve member 54, which is connected via a longitudinal hole 90 in the control valve member 54 and another transverse hole 92 in the control valve member 54 to external air. A fourth O-ring 94 is located in FIG. 2 in the seal. The control valve member 54 is pressed into its lower end position by a spring 96.

(13) A control chamber 98 is arranged below the safety actuator 78. A pressure prevailing in this control chamber 98, like the spring 80, exerts a force upwards on the safety actuator 78. In the drawn position, the control chamber 98 is connected to outside air via a transverse hole 100 in the outer sleeve part 76 and a transverse hole 102 in the inner sleeve part 74 past the second O-ring 84 via holes 88, 90, 92 in the safety actuator 54.

(14) The main control line 58 is also deaerated via a transverse hole 104 in the safety actuator 78, past a O-ring 106 which is not in the seal and which is arranged between the outer sleeve part 76 and the safety actuator 78, a transverse hole 108 in the outer sleeve part 76 and past the third O-ring 86 through the holes 88, 90, 92 in the control valve member 54.

(15) In FIG. 3, the pneumatic nailer is positioned on a workpiece, whereby the contact feeler 14 has reached its upper end position. The pin 18 is therefore located at the lower end of the slot hole 16. During the upward movement of the contact feeler 14 relative to the housing 10, the spring 20 and the damper 22 (only shown in FIG. 1) were pressed together. The damper ram 26 has been pushed a little into the damper housing 24, whereby it may have reached an upper end position inside the damper housing 24. In addition, together with the damper housing 24, the mounting section 28 was pushed upwards so far that the pin 30 now rests against the upper end of the slot hole 32.

(16) On its way up, the upper surface 50 of the contact feeler 14 has taken the free end 48 of the lever 44 with it, so that the actuating surface 52 has shifted the control valve member 54 to its fully actuated position. In this position, the second O-ring 84 and the third O-ring 86 are now in seal so that there is no connection between the holes 88, 90, 92 (see FIG. 2) in the control valve member 54 and the transverse holes 108, 104 and the ring gap between them. At the same time, the fourth O-ring 94 has moved out of the seal so that the line 72 is now connected to the main control line 58 via the transverse hole 108. Since the line 72 is still connected to the outside air via the trigger valve 42, this does not yet trigger a driving-in process.

(17) If the trigger 36 is subsequently actuated, the result is the position shown in FIG. 4. The valve pin 40 has been moved upwards and is now in a fully actuated position where the lower O-ring 62 is in the seal and the upper O-ring 64 has moved out of the seal. Thus the line 72 is aerated past the upper O-ring 64 via the transverse hole 66 from the housing interior 60. The control chamber 98 is also aerated, from line 72 past the fourth O-ring 94, through a transverse bore 110 in the outer sleeve part 76, which forms a check valve with another O-ring 112, and through an annular gap 114 between the outer sleeve part 76 and the safety actuator 78. The force exerted by the pressure in the control chamber 98 and the spring 80 on the safety actuator 78 is so great that it outweighs the force exerted by the pressure in the space 116 above the safety actuator 78 that the safety actuator 78 initially remains in its upper end position. This upper end position of the safety actuator 78 can also be referred to as the trigger position.

(18) Furthermore, in the position of FIG. 4 there is a connection between line 72 and main control line 58, so that when line 72 is aerated a driving-in process is triggered at the same time.

(19) After lifting the pneumatic nailer off the workpiece, the pneumatic nailer quickly reaches the position shown in FIG. 5, in which the contact feeler 14 has already moved a little way down, until the pin 30 rests against the lower end of the slot hole 32 and the effect of the damper 22 begins. The downward movement of the contact feeler 14 is coupled via the lever 44 to a downward movement of the control valve member 54, because the control valve member 54 is in contact with the actuating surface 52 of the lever 44 due to the force exerted by the spring 96 and the free end 48 of the lever 44 is in contact with the upper surface 50 of the contact feeler 14.

(20) At the time shown in FIG. 5 the control valve member 54 has just reached a second switching point at which the fourth O-ring 94 returns to the seal and the third O-ring 86 moves out of the seal. In this way the main control line 58 is shut off from line 72 and, passing the O-ring 106, deaerated through the transverse hole 108, past the third O-ring 86 and through the holes 88, 90, 92 (see FIG. 2) in control valve member 54. The control chamber 98 is still shut off from outside air and remains under pressure so that the safety actuator 78 remains in its trigger position. As a result, contact triggers are possible at any time from the state shown in FIG. 5.

(21) If the pneumatic nailer is not repositioned on the workpiece, the contact feeler 14 continues its downward movement from the position corresponding to the second switching point of the control valve member 54, shown in FIG. 5, under the influence of the damper 22. After a specified time has elapsed, which can range between 1 second and 5 seconds, for example, it reaches the position shown in FIG. 6, which is slightly above its completely unactuated position from FIG. 2.

(22) In the position shown in FIG. 6 the control valve member 54, which also moves downwards coupled to the movement of the contact feeler 14, is directly in front of a first switching point. At this first switching point the second O-ring 84 moves out of the seal, which leads to an immediate deaeration of the control chamber 98 via the transverse holes 100 and 102, past the second O-ring 84 and through the holes 88, 90,92 (see FIG. 2).

(23) FIG. 7 shows the state of the pneumatic nailer again a short time later. At this point, the contact feeler 14 has reached its completely unactuated position and the control valve member 54 has exceeded the first switching point, so that the control chamber 98 is connected to outside air and no longer exerts any force on the safety actuator 78. The force exerted by the pressure in the space 116 on safety actuator 78 then outweighs the force of spring 80, so that safety actuator 78 has shifted to its lower end position.

(24) This lower end position is a safety position in which no further driving-in processes can be triggered, in particular not by contact triggering by repeated positioning of the pneumatic nailer on a workpiece. The pneumatic nailer is thus in a locked state. This is because, regardless of the position of the valve pin 40 and the control valve member 54, the main control line 58 can no longer be ventilated because the transverse hole 104 is shut off by the O-ring 106 which is now in the seal and the two O-rings 118 and 120 which are always in seal. As an additional safety precaution, O-rings 122, 124 are no longer in seal. Between these O-rings 122, 124 there is a hole not shown which additionally connects the control chamber 98 and the main control line 58 with outside air.

(25) Further triggers are only possible again if trigger 36 is released beforehand. Then the safety actuator 78 returns to its trigger position shown in FIG. 2 and the pneumatic nailer is again in a state ready for triggering.

(26) In addition, FIG. 7 also shows the condition of the pneumatic nailer, which occurs when the trigger 36 is actuated before the contact sensor 14 is actuated. In this case, the safety actuator 78 is moved from the pressure built up in space 116 to its safety position, while the control chamber 98 remains connected to outside air. For this reason, the first driving-in process of the pneumatic nailer described in the example must always be carried out individually.

LIST OF REFERENCES NUMBERS

(27) 10 housing 12 handle 14 contact feeler 16 slot hole 18 pin 20 spring 22 damper 24 damper housing 26 damper ram 28 mounting section 30 pin 32 slot hole 34 axis 36 trigger 38 actuation surface 40 valve pin 42 trigger valve 44 lever 46 axis 48 free end 50 upper surface 52 actuating surface 54 control valve member 56 control valve 58 main control line 60 housing interior 62 lower O-ring 64 upper O-ring 66 transverse hole 68 sleeve 70 annular gap 72 line 74 inner sleeve part 76 outer sleeve part 78 safety actuator 80 spring 82 first O-ring 84 second O-ring 86 third O-ring 88 transverse hole 90 transverse hole 92 further transverse hole 94 fourth O-ring 96 spring 98 control chamber 100 transverse hole 102 transverse hole 104 transverse hole 106 O-ring 108 transverse hole 110 transverse hole 112 further O-ring 114 annular gap 116 space 118 O-ring 120 O-ring 122 O-ring 124 O-ring