Pyrotechnic drive device

Abstract

A drive device includes: a handheld housing in which a piston element is disposed for delivering energy to a fastening element to be driven in a driving direction; a propellant charge, particularly a replaceable propellant charge; a combustion chamber disposed between the propellant charge and the piston element and extending about a central axis; and an actuator by means of which the energy to be transferred from the propellant charge to the piston element can be modified in such a way that the energy can be set, wherein a ventilation passage connected to the combustion chamber can be exposed by means of a movable slider of the actuator, wherein the ventilation passage opens into the combustion chamber through a ventilation opening which can be partially or completely covered by the slider, and wherein the cross-sectional area of ​​the ventilation opening increases in the driving direction.

Description

Technical Field

[0001] This invention relates to a driving device. Background Technology

[0002] Existing technology discloses a handheld drive device with a propellant charge, in which the combustion gases produced after the pyrotechnic charge is ignited expand in a combustion chamber. This accelerates the piston, acting as an energy transfer device and driving the fastening element into the workpiece. Combustion residues may contaminate the combustion chamber.

[0003] US 6,321,968 B1 describes a drive mechanism with a propellant charge, wherein the combustion chamber is divided into an upper sub-chamber and a lower sub-chamber by an orifice plate. The dead space volume of the drive mechanism can be adjusted to adjustably change the drive energy of the mechanism. For this purpose, a slider similar to a valve can be adjusted in a direction perpendicular to the drive axis. In this case, the combustion chamber also has a dead space when the slider is in the closed position, which is formed as a void in the sidewall of the combustion chamber. Summary of the Invention

[0004] The object of the present invention is to provide a drive device that allows the drive energy to be easily set (as wide as possible, if necessary) given a propellant load.

[0005] According to one aspect, a drive device includes: a handheld housing in which a piston element is arranged for delivering energy to a fastening element to be driven in a driving direction; a propellant charge, particularly a replaceable propellant charge; a combustion chamber disposed between the propellant charge and the piston element and extending about a central axis; and an actuator by means of which the energy to be transferred from the propellant charge to the piston element can be modified in such a way that the energy can be set, wherein a ventilation passage connected to the combustion chamber can be exposed by a movable slider of the actuator, wherein the ventilation passage opens into the combustion chamber through a ventilation opening which can be partially or completely covered by the slider, and wherein the cross-sectional area of ​​the ventilation opening increases in the driving direction. As a result, during slider displacement, initially only a very narrow portion of the ventilation opening is exposed, and then a wider portion of the ventilation opening is exposed. This allows the set energy transferred to the piston element to depend largely linearly on the displacement distance of the slider. Preferably, the ventilation opening is arranged in the cylindrical, particularly preferably circular, portion of the combustion chamber.

[0006] An advantageous embodiment is characterized in that the drive device has a plurality of ventilation channels, each of which opens into the combustion chamber through a ventilation opening and the cross-sectional area of ​​each channel increases along the drive direction.

[0007] According to another aspect, a drive device includes: a handheld housing in which a piston element is arranged for supplying energy to a fastening element to be driven in a driving direction; a propellant charge, particularly a replaceable propellant charge; a combustion chamber disposed between the propellant charge and the piston element and extending about a central axis; and an actuator by which the energy to be transferred from the propellant charge to the piston element can be modified in such a way that the energy can be set. The combustion chamber has an internal thread and a preferably cylindrical guide portion. The actuator is disposed in the combustion chamber and has an external thread engaging the internal thread and a support portion for mounting the actuator in the guide portion. The thread clearance between the external thread and the internal thread is greater than the support clearance between the support portion and the guide portion. As a result, the force and torque acting on the actuator during combustion in the combustion chamber are transmitted to the guide portion via the support portion, thereby reducing the load on the external thread and the internal thread. This reduces the likelihood of the actuator getting stuck due to combustion residue in the combustion chamber, allowing for easier actuator adjustment. Preferably, the thread clearance is at least twice, and particularly preferably three times, the support clearance.

[0008] An advantageous embodiment is characterized in that the combustion chamber has another guide portion, preferably cylindrical, wherein the actuator has another support portion for mounting the actuator in the other guide portion, wherein the thread clearance between the external and internal threads is greater than the other support portion clearance between the other support portion and the other guide portion. Preferably, the external thread is arranged along a central axis between the support portion and the other support portion. Also preferably, the other support portion clearance is approximately the same size as the support portion clearance.

[0009] An advantageous embodiment is characterized in that the internal and / or external threads do not have any thread tail.

[0010] An advantageous embodiment is characterized in that the internal and / or external threads have one or more feed grooves, particularly, the one or more feed grooves extending parallel to the drive direction. Another advantageous embodiment is characterized in that the actuator has one or more feed holes, particularly, the one or more feed holes extending parallel to the drive direction.

[0011] An advantageous embodiment is characterized in that the ventilation passage connected to the combustion chamber can be exposed by means of a movable slider of the actuator. Another advantageous embodiment is characterized in that the initial position of the piston element relative to the combustion chamber can be set by means of the actuator.

[0012] An advantageous embodiment is characterized in that the actuator includes a threaded sleeve, preferably having a cylindrical inner wall.

[0013] Typically, the piston element is guided in the slider at least during the first part of its movement. Depending on the design details, the exposure level or number of ventilation channels can be varied by adjusting the slider in the axial and / or circumferential directions.

[0014] For the purposes of this invention, the ventilation duct can be any space that can be selectively added to the volume of the combustion chamber by means of setting elements, so as to change the drive energy in a defined manner by the additional expansion space. Preferably, but not necessarily, the ventilation duct can be connected to an external space in this case. Alternatively or otherwise, the ventilation duct may also have a dead space volume that is not connected to an external space.

[0015] For the purposes of this invention, drive energy is understood to refer to the energy transferred to a given fastening element under a given propellant charge. If these boundary conditions are specified, the resulting drive energy of the fastening element can be changed by an actuator in a way that allows the drive energy to be set.

[0016] For the purposes of this invention, a piston element is any device that applies kinetic energy by igniting the charge, wherein this kinetic energy is ultimately transferred to a fastening element. The piston element typically takes the form of a piston, particularly a cylindrical piston. The piston head may be provided with a gap or other structures that further promote turbulence and uniform expansion of the combustion gases.

[0017] In this invention, the central axis is an axis that is at least parallel to the movement of the fastening element and passes through the center of the combustion chamber. Preferably, the central axis passes through both the center of the combustion chamber and the center of the fastening element.

[0018] For the purposes of this invention, the fastening element is generally any fastener that can be driven in, such as a nail, bolt, or screw.

[0019] Typically, the slider advantageously has a preferably cylindrical inner wall that forms part of the combustion chamber. In this arrangement, the slider conveniently also serves to guide the piston element in the first part of the piston's movement.

[0020] To enable easy and intuitive adjustment of the drive energy, the actuator has an operating part that can pivot about a central axis. The operating part can be any suitable device for manual adjustment, such as a rotatable sleeve, a pivotable knob, etc., as a particularly preferred variant. The pivotability of the operating part about the central axis allows for easy adjustment while simultaneously enabling effective visual monitoring of the set value. This arrangement allows for easy adjustment even under adverse conditions such as wearing work gloves.

[0021] In this context, pivoting the operating part around a central axis refers to deflecting the operating part from a previous position and approximately perpendicular to the axis. The radius of curvature of the torque line or trajectory of the operating part is preferably not less than the distance between the operating part and the central axis. Preferably, but not necessarily, pivoting is rotation about the central axis. In this case, the operating part and the slider are preferably connected together to rotate together, such that rotating the operating part also rotates and adjusts the slider, thereby regulating the driving energy.

[0022] Advantageously, the slider typically has a collar extending about a central axis and engaging in an overlapping manner within a recess in the combustion chamber housing, wherein at least a portion of the ventilation passage is formed as an axially extending gap between the collar and the combustion chamber housing. In this manner, the overlap results in a tight seal even under high gas pressures. Furthermore, the connection between the ventilation passage and the combustion chamber can be directly exposed at the charge-side end of the combustion chamber in a way that allows for setting the degree of exposure, thereby permitting adjustment of the drive energy over a wide range.

[0023] Other features and advantages of the invention will become apparent from the exemplary embodiments and dependent claims. Preferred exemplary embodiments of the invention are described below and explained in detail with reference to the accompanying drawings. Attached Figure Description

[0024] Figure 1 An overall spatial view of the drive device according to the present invention is shown.

[0025] Figure 2 The longitudinal section of the combustion chamber is shown.

[0026] Figure 3 The longitudinal section of the combustion chamber is shown when the actuator is in a low drive energy position.

[0027] Figure 4 The longitudinal section of the combustion chamber is shown when the actuator is in a high drive energy position.

[0028] Figure 5 It shows Figure 4 Details of the longitudinal section.

[0029] Figure 6 A spatial view showing details of the actuator is provided. Detailed Implementation

[0030] Figure 1 The drive mechanism is shown. This drive mechanism includes a handheld housing 1 in which a piston element, in the form of a piston, is held. The surface of the piston defines a combustion chamber in which the combustion gases of the pyrotechnic charge expand to accelerate the piston.

[0031] The piston, imbued with kinetic energy, acts together with the end tappet on a fastening element (not shown), thereby driving the fastening element toward the workpiece. Figure 1 (in the right side of the middle). In particular, the fastening element can be held in a module or box (not shown), which is alternatively attached to the forward holding area 1a of the drive unit 1.

[0032] In the current configuration, the charge is held in a sheet metal reservoir 4a. Reservoir 4a has an impact detonator, which is inserted into the reservoir support via a corresponding charging mechanism (in the current configuration, via the cartridge bar 4) before ignition. The reservoir 4a and reservoir support are then arranged rotationally symmetrically about a central axis A. In this current example, central axis A is simultaneously the central axis of both the combustion chamber and the piston element.

[0033] Figure 2 The diagram shows a combustion chamber 20, formed by a combustion chamber housing 21. The combustion chamber 20 is arranged between a circular opening 22 of a reservoir support 23 and the surface of a piston (not shown). During combustion, the reservoir rests against and is closed at the reservoir support. Multiple internal threads 24 are present in the region of the combustion chamber 20 within the combustion chamber housing 21. The combustion chamber 20 is connected to multiple ventilation channels 25, particularly two or three ventilation channels, each opening into the combustion chamber 20 through a ventilation opening 26. The cross-sectional area of ​​each ventilation opening 26 increases along the drive direction 27. The ventilation openings 26 are arranged in the cylindrical portion of the combustion chamber 20. Furthermore, the combustion chamber 20 has a cylindrical guide portion 33 and another guide portion 32. The internal threads 24 are arranged along a central axis A between the guide portion 33 and the other guide portion 32.

[0034] exist Figure 3 , Figure 4 and Figure 5 In the diagram, combustion chamber 20 is shown with actuator 28 arranged therein. Actuator 28 includes a threaded sleeve with a cylindrical inner wall and piston guide 28a. The energy to be transferred from propellant charge to piston element 34 is altered by actuator 28 in such a way that ventilation passage 25 is gradually exposed by actuator 28 and, additionally or alternatively, the energy is set by setting the initial position of piston element 34 relative to combustion chamber 20 by actuator 28. The fact that the cross-sectional area of ​​ventilation opening 26 increases along the drive direction 27 means that during the displacement of actuator 28, initially only a very narrow portion of ventilation opening 26 is exposed, and then a wider portion of ventilation opening 26 is exposed. As a result, the energy to be transferred to piston element 34 has a linear relationship with the displacement distance of actuator 28.

[0035] The actuator 28 has an external thread 29 that engages with the internal thread 24, a support portion 30 for mounting the actuator 28 in the guide portion 33, and another support portion 31 for mounting the actuator 28 in another guide portion 32. The external thread 29 is arranged along the central axis A between the support portion 30 and the other support portion 31. The thread clearance between the external thread 29 and the internal thread 24 is approximately four times the support clearance between the support portion 30 and the guide portion 33 and / or the support clearance between the other support portion 31 and the other guide portion 32. As a result, the external thread 29 and the internal thread 24 are subjected to relatively small force and torque loads during combustion.

[0036] The flank angle between the front side 35 of the external thread 29 and / or the internal thread 24 and the central axis A is between 0° and 60°, preferably between 30° and 45°. A tree-root fillet is advantageously provided at the transition from the front side 35 to the thread base of the external thread 29 or to the thread back of the internal thread 24.

[0037] exist Figure 6 The details of actuator 60 are depicted in a spatial view. Actuator 60 includes a piston guide 61 and a slider 62, which is axially displaceable relative to piston guide 61 but rotates with piston guide 61 during rotation about central axis A'. For this purpose, piston guide 61 has two claws 63 that engage in two corresponding recesses 64 in slider 62 for co-rotation but axial displacement. In an exemplary embodiment not shown, piston guide is engaged with slider by one, three, four, five or more claws. Advantageously, all claws engage with the corresponding recesses simultaneously, thereby reducing lateral forces on slider. This simultaneous engagement is improved by designing the claws as bending springs.

[0038] The piston guide 61 itself is connected to the operating part 10 in a manner that they rotate together. Figure 1 They rotate together, causing the piston guide 61 to form a mechanical connection between the operating part 10 and the slider 62. The operating part 10, together with the piston guide 61 and the slider 62, forms an actuator 60 for changing the driving energy of the drive device.

[0039] The slider 62 has an external thread 65, which is formed to interact with an internal thread, such as internal thread 24, of the combustion chamber housing (not shown). Figure 2Complementary. The external thread 65 does not have a threaded tail, but ends abruptly with a scraper 66, which helps to clean combustion residue from the combustion chamber when necessary. To allow or assist in the removal of such combustion residue, the external thread 65 has multiple conveying grooves 67 and multiple conveying holes 68, which extend generally parallel to the drive unit in their respective cases. As a result, the actuator 60 can still be easily adjusted when necessary.

[0040] The adjustment of the driving energy is carried out as follows:

[0041] The external thread 65 of slider 62 is screwed into the internal thread of the combustion chamber housing. Rotating the operating part about the central axis A, and thus rotating the piston guide 61 and slider 62 accordingly, forces slider 62 to undergo controlled axial displacement. In preparation for drive operation, the desired drive energy is set to the energy level marked on the operating part by rotating the operating part. This forced control, as described above, positions slider 62 axially relative to the combustion chamber housing. As a result, any ventilation passages here can be partially exposed to the through opening (low drive energy, Figure 3 ) or is blocked (maximum driving energy, Figure 4 ).

[0042] The invention has been described with reference to several exemplary embodiments of the installation tool. It will be understood that all features of the various exemplary embodiments can also be implemented in a single device in any desired combination, provided that these features do not contradict each other. It should be noted that the invention is also applicable to other applications.

Claims

1. A driving device, the driving device comprising: A handheld housing containing a piston element for supplying energy to a fastening element to be driven in the driving direction; Propellant loading; A combustion chamber, which is arranged between the propellant charge and the piston element and extends about a central axis; The actuator is capable of altering the energy to be transferred from the propellant charge to the piston element in such a way that the energy can be set. The drive unit has multiple ventilation channels connected to the combustion chamber, which are exposed by a movable slider of the actuator. The multiple ventilation channels open into the combustion chamber through ventilation openings that can be partially or completely covered by the slider. The cross-sectional area of ​​each of the multiple ventilation openings increases along the drive direction.

2. The driving device as claimed in claim 1, wherein, The propellant charge is a replaceable propellant charge.

3. The driving device as claimed in any of the preceding claims, wherein, The ventilation opening is located in the cylindrical section of the combustion chamber.

4. The driving device as claimed in claim 3, wherein, The ventilation opening is located in the cylindrical section of the combustion chamber.

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