Pyrotechnic driving device

Abstract

A driving device is provided comprising a hand-held housing with a piston member arranged therein for transmitting energy to a securing element to be driven in; an interchangeable propellant charge and a combustion chamber arranged between the propellant charge and the piston member, the combustion chamber extending around a central axis (A); and an actuator, by which the energy transmitted by the propellant charge to the piston member can be variably adjusted. The driving device also includes a blow-off channel connected to the combustion chamber that can be exposed by a movable slide of the actuator and the movable slide comprises a body which completely encircles the central axis (A).

Claims

1. A driving-in device, comprising: a hand-held housing with a piston element therein for transmitting an amount of energy to a fastening element to be driven in; a replaceable propelling charge; a combustion chamber provided between the replaceable propelling charge and the piston element, the combustion chamber extending about a central axis; a piston guide located in front of the combustion chamber, wherein the piston guide is rotatable relative to the hand-held housing about the central axis axis; a blow-off channel connected to the combustion chamber; and, an actuator that is adjustable to modify the amount of energy to be transmitted to the piston element by the replaceable propelling charge, the actuator comprising a movable slide comprising a body which completely encircles the central axis, wherein the moveable slide is supported in a forced guide, and the moveable slide is rotated about the central axis to adjust a cross section of the blow-off channel, and rotation of the moveable slide about the central axis moves the moveable slide in a direction of the central axis and releases gas from the combustion chamber into the blow-off channel, and the piston guide and the moveable slide are axially moveable relative to each other and unrotatable relative to each other.

2. The driving-in device as claimed in claim 1, wherein the forced guide comprises a multi-start thread.

3. The driving-in device as claimed in claim 1, wherein the actuator comprises an operating unit that is pivotable about the central axis.

4. The driving-in device as claimed in claim 3, wherein the moveable slide has a cylindrical inner wall formed as part of the combustion chamber.

5. The driving-in device as claimed in claim 3, wherein the operating unit and the moveable slide are connected in a rotationally fixed manner.

6. The driving-in device as claimed in claim 1, comprising a piston guide located in front of the combustion chamber, wherein the piston guide is rotatable relative to the housing about the central axis.

7. The driving-in device as claimed in claim 5, wherein the moveable slide has a collar that encircles the central axis, which engages in an overlapping manner in a recess of a combustion chamber housing, wherein at least part of the blow-off channel is formed as an axially extending recess between the collar and the combustion chamber housing.

8. The driving-in device as claimed in claim 5, wherein the moveable slide has a cylindrical inner wall formed as part of the combustion chamber.

9. The driving-in device as claimed in claim 1, wherein the moveable slide has a cylindrical inner wall formed as part of the combustion chamber.

10. The driving-in device as claimed in claim 2, wherein the moveable slide has a cylindrical inner wall formed as part of the combustion chamber.

11. The driving-in device as claimed in claim 2, wherein the actuator comprises an operating unit that is pivotable about the central axis.

12. The driving-in device as claimed in claim 6, wherein the actuator comprises an operating unit that is pivotable about the central axis.

13. The driving-in device as claimed in claim 2, comprising the piston guide located in front of the combustion chamber, wherein the piston guide is rotatable relative to the housing about the central axis.

14. The driving-in device as claimed in claim 5, comprising the piston guide located in front of the combustion chamber, wherein the piston guide is rotatable relative to the housing about the central axis.

15. The driving-in device as claimed in claim 3, wherein the moveable slide has a collar that encircles the central axis, which engages in an overlapping manner in a recess of a combustion chamber housing, wherein at least part of the blow-off channel is formed as an axially extending recess between the collar and the combustion chamber housing.

16. The driving-in device as claimed in claim 1, wherein the moveable slide has a collar that encircles the central axis, which engages in an overlapping manner in a recess of a combustion chamber housing, wherein at least part of the blow-off channel is formed as an axially extending recess between the collar and the combustion chamber housing.

17. The driving-in device as claimed in claim 6, wherein the moveable slide has a collar that encircles the central axis, which engages in an overlapping manner in a recess of a combustion chamber housing, wherein at least part of the blow-off channel is formed as an axially extending recess between the collar and the combustion chamber housing.

18. The driving-in device as claimed in claim 2, wherein the moveable slide has a collar that encircles the central axis, which engages in an overlapping manner in a recess of a combustion chamber housing, wherein at least part of the blow-off channel is formed as an axially extending recess between the collar and the combustion chamber housing.

19. The driving-in device as claimed in claim 6, wherein the moveable slide has a cylindrical inner wall formed as part of the combustion chamber.

20. The driving-in device as claimed in claim 14, wherein the moveable slide has a cylindrical inner wall formed as part of the combustion chamber.

21. The driving-in device as claimed in claim 16, wherein the moveable slide has a cylindrical inner wall formed as part of the combustion chamber.

Description

BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWING(S)

(1) Further features and advantages of the invention result from the embodiment example as well as from the dependent claims. A preferred embodiment example of the invention will be described below and will be explained in more detail by means of the attached drawings, wherein:

(2) FIG. 1 shows a spatial overall view of a driving-in device according to the invention;

(3) FIG. 2 shows a spatial detailed view of the driving-in device from FIG. 1;

(4) FIG. 3 shows a spatial sectional view of the driving-in device from FIG. 1 along a central axis in the rear region of a piston guide;

(5) FIG. 4 shows a spatial sectional view of the driving-in device from FIG. 1 along a central axis in a front region of a piston guide;

(6) FIG. 5 shows a detailed view of the region of the piston guide from FIG. 3 in an adjustment with reduced drive-in energy;

(7) FIG. 6 shows the detailed view from FIG. 5 in an adjustment with maximum drive-in energy;

(8) FIG. 7 shows a spatial sectional view of the driving-in device from FIG. 1 transversely to a central axis in a rear region of a piston guide;

(9) FIG. 8 shows a sectional view as in FIG. 7 with a section plane offset slightly rearwards and with the piston element removed;

(10) FIG. 9 shows a spatial view of a slide of the driving-in device from FIG. 1;

(11) FIG. 10 shows the slide from FIG. 9 in cooperation with a piston guide.

DETAILED DESCRIPTION OF THE INVENTION

(12) A driving-in device according to the invention comprises a hand-held housing 1, in which a piston element in the form of a piston 2 is received. A surface 2a of the piston 2 delimits a combustion chamber 3, in which the combustion gases of a pyrotechnical charge expand in order to accelerate the piston 2.

(13) The piston 2 to which motion energy is applied impinges with an end-side plunger on to a fastening element (not shown), which as a result is driven into a workpiece. The fastening element may in particular be received in a module or magazine (not shown), which is attached in a replaceable manner in a front holding region 1a of the driving-in device 1.

(14) The charge is presently received in a cartridge 4a made from metal sheet. The cartridge 4a has an impact fuse and is inserted prior to the ignition in a cartridge store 4 by a corresponding loading mechanism, presently by means of a magazine strip. The cartridge and the cartridge store 4 are formed to be rotationally symmetrical about a central axis A. In the present example, the central axis A is at the same time a middle axis of the combustion chamber 3 and of the piston element 2.

(15) The combustion chamber 3 is located between a circular opening of the cartridge store 4 and of the surface 2a of the piston 2. Presently, a depression 2b is formed in the piston 2, which contributes to an improved turbulence of the combustion gases and forms part of the delimitation of the combustion chamber 3.

(16) The combustion chamber 3 is formed in a first section as a hollow cylindrical, substantially sleeve-shaped body 6. This body 6 is at the same time a slide that can be rotated about the central axis A and can in the course of this be modified in its position in the direction of the central axis A for an adjustable release of one or more blow-off channels 7 for example with a step-shaped cross section.

(17) The blow-off chamber 7 has, spread over the circumference thereof, a plurality of recesses 7a in a combustion chamber housing 8. The recesses 7a extend axially in the direction parallel to the central axis A and open in a section of the blow-off channel 7 with a larger volume, which section extends between the combustion chamber housing 8 and a piston guide 5.

(18) In the combustion chamber housing 8, a cylindrical recess with a multi-start internal thread 8a is located in the region of the combustion chamber. The slide 6 is screwed with a corresponding external thread 6a into the opening of the combustion chamber housing 8. A rotation of the slide 6 about the central axis A therefore effects a positively controlled axial offset of the slide 6.

(19) The slide 6 is provided with a collar 6b extending rearwards or in the direction of a bottom of the combustion chamber 3, which collar engages, in an axially overlapping manner, in the recess of the combustion chamber housing 8. Depending on the axial position of the slide 6, a modifiable passage 9 from the combustion chamber 3 into the recesses or blow-off channels 7a is released (see FIG. 5). In the case of a slide 6 offset completely rearwards, the passage 9 is closed (see FIG. 6). If an open passage 9 is adjusted, then this is part of the blow-off channel 7a, 7. The passage is provided in the axial direction directly in front of the bottom of the combustion chamber 3, so that combustion gases can escape into the blow-off channel as early as immediately prior to the beginning of the piston movement. As a result, a particularly large range of energy reduction can be achieved, depending on the adjustment of the slide 6.

(20) On a front side of the slide 6, axial protrusions 6c are formed which, if needed, partially or completely scrape off any deposited dirt.

(21) A guiding of the piston 2 is carried out both in the slide 6 and in the piston guide 5 following on from the slide 6 in the driving-in direction. The piston guide 5 is received in the combustion chamber housing so as to be rotatable about the central axis A. The piston guide 5 is coupled with the slide 6 by means of two claws 5a, and the axially protruding claws 5a engage in two corresponding recesses 6d in the slide 6 in a rotationally fixed manner, but so as to be axially displaceable (see FIG. 10). In particular embodiment examples (not shown), the piston guide is coupled with the slide by means of 1, 3, 4, 5 or more claws. Depending on the position of the slide 6, there is therefore a gap over part of the circumference between the slide 6 and the piston guide 5. The length of the slide 6 is correspondingly dimensioned such that the maximum desired driving-in energy is achieved, before the rear end of the piston element 2 covers the gap. The gap also connects the combustion chamber with the blow-off channel 7.

(22) A front end of the piston guide 5 is coupled with an operating unit 10 in a rotationally fixed manner, so that the piston guide 5 at the same time forms a mechanical connection between the operating unit 10 and the slide 6. The operating unit 10 is presently formed as a sleeve that is rotatable in the combustion chamber housing, which sleeve is arranged to be substantially concentric about the central axis A in a front region of the housing 1 of the driving-in device.

(23) The operating unit 10 forms, together with the piston guide 5 and the slide 6, an actuator for modifying the drive-in energy of the driving-in device 1. This adjustment and the driving-in process work as follows:

(24) After a driving-in process, the piston element is in a partially undefined position, which is however displaced as far as possible towards the front. The combustion chamber housing 8 is located in a position pushed to the maximum towards the rear of the driving-in device. The terms front and rear are presently always selected in relation to the driving-in direction.

(25) Subsequently, in order to prepare the next driving-in process, the desired drive-in energy is adjusted by rotating the sleeve 10 to the energy step marked on the operating unit. This leads, via the forced control described above, to a selected axial position of the slide 6 relative to the combustion chamber housing 8. As a result, the blow-off channel is released or closed in a defined manner via the passage 9 (maximal drive-in energy).

(26) In the present example of the invention, with reduced drive-in energy, a corresponding part of the propelling gases or exhaust gases is discharged towards the outside via the described channels 7a, 7. In other embodiments, depending on requirements, also a closed dead space volume may be provided, wherein for example the blow-off channels 7a are only used as an optional space extension of the combustion chamber and are not connected with the outside any further. In yet other embodiments it may be provided that the gases passed over the blow-off channels are used for returning the piston by means of gas pressure.

(27) In the present embodiment example, a disassembly of the piston element 2 and the combustion chamber housing 8 is enabled by means of an additional closure ring 11 that is located behind the operating unit 10. The closure ring carries a button 10a that is used for securing the operating unit 10 and must be pressed in order to adjust the operating unit. The closure ring 11 is secured in an analogous manner via a button 11 a on the housing of the driving-in device 1.

(28) In an alternative embodiment of the invention, the function mentioned above for disassembling the driving-in device may also be integrated into the operating unit 10.