SETTING TOOL

Description

[0001] The present invention relates to a setting tool for driving fastening elements into a substrate.

[0002] Such setting tools typically have a fastener receptacle, from which a fastener is inserted into the substrate along a setting axis. A driving element is driven by a drive along the setting axis toward the fastener.

[0003] US Pat. No. 6,830,173 B2 discloses a setting tool with a drive for a driving element. The drive comprises an electrical capacitor and a coil. To drive the driving element, the capacitor is discharged via the coil, exerting a Lorentz force on the driving element, causing it to move toward a nail.

[0004] US 2013 / 098963 A1 discloses the preamble of independent claim 1.

[0005] Another setting tool is also known from EP 1 839 815 A1.

[0006] The object of the present invention is to provide a setting tool of the aforementioned type in which a high degree of efficiency and / or a good setting quality is guaranteed.

[0007] The object is achieved with a setting tool for driving fastening elements into a substrate, comprising a receptacle which is intended to receive a fastening element, a driving element which is intended to convey a fastening element received in the receptacle along a setting axis into the substrate, a drive which is intended to drive the driving element along the setting axis towards the fastening element, wherein the drive has an excitation coil through which current flows and which generates a magnetic field which accelerates the driving element towards the fastening element, and a stop element which supports the driving element against movement towards the excitation coil when the driving element is in a position ready for setting, wherein the driving element is spaced from the excitation coil in the position ready for setting. The setting tool can preferably be used hand-held.Alternatively, the setting device can be used stationary or semi-stationary.

[0008] A capacitor, within the meaning of the invention, is an electrical component that stores electrical charge and the associated energy in an electric field. In particular, a capacitor has two electrically conductive electrodes between which the electric field develops when the electrodes are electrically charged to different degrees. A fastening element, within the meaning of the invention, is understood to be, for example, a nail, a pin, a clamp, a clip, a bolt, in particular a threaded bolt, or the like.

[0009] A preferred embodiment is characterized in that an air gap forms between the driving element and the excitation coil when the driving element is in a position ready for insertion. The air gap preferably has a gap width of between 0 and 0.5 mm, particularly preferably between 0.01 mm and 0.2 mm, for example between 0.02 mm and 0.1 mm.

[0010] A preferred embodiment is characterized in that the stop element has a stop surface facing the receptacle, and the driving element has a counter surface facing away from the receptacle, and wherein the stop surface and the counter surface abut one another when the driving element is in a position ready for insertion. Preferably, the stop surface and / or the counter surface are arranged on the insertion axis or around the insertion axis. Likewise, the stop surface and / or the counter surface are preferably convex, particularly preferably spherical.

[0011] A preferred embodiment is characterized in that a projection of the stop element in the direction of the setting axis is arranged radially within a projection of the excitation coil in the direction of the setting axis. The stop element is preferably arranged radially within the excitation coil with respect to the setting axis.

[0012] A preferred embodiment is characterized in that the drive comprises a soft magnetic frame on which the excitation coil is arranged. The excitation coil is preferably embedded in the soft magnetic frame. The driving element is preferably spaced from the soft magnetic frame in the ready-to-insert position. Particularly preferably, an additional air gap forms between the driving element and the soft magnetic frame when the driving element is in the ready-to-insert position.

[0013] A preferred embodiment is characterized in that the soft magnetic frame is annular, with a projection of the stop element in the direction of the setting axis being arranged radially within a projection of the soft magnetic frame in the direction of the setting axis. The stop element is preferably arranged radially within the soft magnetic frame with respect to the setting axis.

[0014] A preferred embodiment is characterized in that the stop element and / or the driving element comprises a damper, which has the stop surface or the counter surface, respectively. The damper preferably dampens the impact of the driving element against the stop element.

[0015] A preferred embodiment is characterized in that the drive comprises an electrical capacitor, which is preferably arranged on the setting axis or around the setting axis, and upon discharge, current flows through the excitation coil to generate the magnetic field. A further embodiment is characterized in that the drive has a squirrel-cage rotor arranged on the driving element, which is penetrated by the magnetic field generated by the excitation coil.

[0016] The invention is illustrated in several embodiments in the drawings.

[0017] They show: Fig. 1 a setting tool in a longitudinal section and Fig. 2 a setting tool in a longitudinal section.

[0018] In Fig. 1 A hand-held setting tool 10 for driving fastening elements into a substrate (not shown) is shown. The setting tool 10 has a receptacle 20 designed as a bolt guide, in which a fastening element 30 designed as a nail is received in order to be driven into the substrate along a setting axis A (in Fig. 1 to the left). For feeding fastening elements to the receptacle, the setting tool 10 comprises a magazine 40 in which the fastening elements are stored individually or in the form of a fastening element strip 50 and are gradually transported into the receptacle 20. The magazine 40 has a spring-loaded feed element (not further designated) for this purpose. The setting tool 10 has a driving element 60 which comprises a piston plate 70 and a piston rod 80. The driving element 60 is provided for conveying the fastening element 30 out of the receptacle 20 along the setting axis A into the subsurface. The driving element 60 with its piston plate 70 is guided in a guide cylinder 95 along the setting axis A.

[0019] The driving element 60 is in turn driven by a drive comprising a squirrel-cage rotor 90 arranged on the piston plate 70, an excitation coil 100, a soft-magnetic frame 105, a switching circuit 200, and a capacitor 300 with an internal resistance of 5 mOhm. The squirrel-cage rotor 90 consists of a preferably annular, particularly preferably circular, element with a low electrical resistance, for example made of copper, and is attached to the piston plate 70 on the side of the piston plate 70 facing away from the receptacle 20, for example, soldered, welded, glued, clamped, or positively connected. In embodiments not shown, the piston plate itself is designed as a squirrel-cage rotor.The switching circuit 200 is designed to cause a rapid electrical discharge of the previously charged capacitor 300 and to conduct the resulting discharge current through the excitation coil 100, which is embedded in the frame 105. The frame preferably has a saturation flux density of at least 1.0 T and / or an effective specific electrical conductivity of at most 10 6 S / m, so that a magnetic field generated by the excitation coil 100 is amplified by the frame 105 and eddy currents in the frame 105 are suppressed.

[0020] In a position ready for setting of the driving element 60 ( Fig. 1 ), the driving element 60 with the piston plate 70 is inserted into an unspecified annular recess in the frame 105 such that the squirrel-cage rotor 90 is arranged at a short distance from the excitation coil 100. As a result, an excitation magnetic field, which is generated by a change in an electrical excitation current flowing through the excitation coil, permeates the squirrel-cage rotor 90 and, in turn, induces an annular circulating electrical secondary current in the squirrel-cage rotor 90. This building and thus changing secondary current in turn generates a secondary magnetic field which is opposite to the excitation magnetic field, whereby the squirrel-cage rotor 90 experiences a Lorentz force repelling it from the excitation coil 100, which drives the driving element 60 towards the receptacle 20 and the fastening element 30 received therein.

[0021] The setting tool 10 further comprises a housing 110 in which the drive is accommodated, a handle 120 with an actuating element 130 designed as a trigger, an electrical energy store 140 designed as a rechargeable battery, a control unit 150, a trigger switch 160, a contact pressure switch 170, a means designed as a temperature sensor 180 arranged on the frame 105 for detecting a temperature of the excitation coil 100 and electrical connecting lines 141, 161, 171, 181, 201, 301 which connect the control unit 150 to the electrical energy store 140, the trigger switch 160, the contact pressure switch 170, the temperature sensor 180, the switching circuit 200 and the capacitor 300, respectively. In embodiments not shown, the setting tool 10 is supplied with electrical energy by means of a power cable instead of the electrical energy storage device 140 or in addition to the electrical energy storage device 140.The control unit comprises electronic components, preferably interconnected on a circuit board to form one or more control circuits, in particular one or more microprocessors.

[0022] If the setting tool 10 is placed on a non-shown surface (in Fig. 1 left) is pressed, a pressing element (not further identified) actuates the pressing switch 170, which then transmits a pressing signal to the control unit 150 via the connecting line 171. Triggered by this, the control unit 150 initiates a capacitor charging process, in which electrical energy is conducted via the connecting line 141 from the electrical energy storage device 140 to the control unit 150 and via the connecting lines 301 from the control unit 150 to the capacitor 300 in order to charge the capacitor 300. The control unit 150 comprises for this purpose a switching converter (not further identified) which converts the electrical current from the electrical energy storage device 140 into a suitable charging current for the capacitor 300. When the capacitor 300 is charged and the driving element 60 is in its Fig. 1 The setting tool 10 is in a ready-to-set state when the setting tool is in the position shown. Because the charging of the capacitor 300 is only effected by pressing the setting tool 10 against the substrate, a setting process is only possible when the setting tool 10 is pressed against the substrate, in order to increase the safety of bystanders. In embodiments not shown, the control unit initiates the capacitor charging process as soon as the setting tool is switched on, when the setting tool is lifted from the substrate, or when a previous driving process is completed.

[0023] When the setting tool 10 is ready for use, the actuating element 130 is actuated, for example, by pulling with the index finger of the hand grasping the handle 120, the actuating element 130 actuates the trigger switch 160, which then transmits a trigger signal to the control unit 150 via the connecting line 161. Triggered by this, the control unit 150 initiates a capacitor discharge process, in which electrical energy stored in the capacitor 300 is conducted from the capacitor 300 to the excitation coil 100 by means of the switching circuit 200, thereby discharging the capacitor 300.

[0024] The Fig. 1 The schematically illustrated circuit 200 comprises two discharge lines 210, 220, which connect the capacitor 300 to the excitation coil 200, and of which at least one discharge line 210 is interrupted by a normally open discharge switch 230. The circuit 200 forms an electrical oscillating circuit with the excitation coil 100 and the capacitor 300. Oscillation of this oscillating circuit and / or negative charging of the capacitor 300 may have a negative effect on the efficiency of the drive, but can be prevented with the aid of a freewheeling diode 240. The discharge lines 210, 220 are electrically connected to an electrode 310, 320 of the capacitor 300 by means of electrical contacts 370, 380 of the capacitor 300 arranged on an end face 360 of the capacitor 300 facing the receptacle 20, for example by soldering, welding, screwing, clamping or form-fitting.The discharge switch 230 is preferably suitable for switching a high-current discharge current and is designed, for example, as a thyristor. Furthermore, the discharge lines 210, 220 are spaced closely apart to minimize any parasitic magnetic field induced by them. For example, the discharge lines 210, 220 are combined to form a bus bar and held together by a suitable means, such as a holder or a clamp. In embodiments not shown, the freewheeling diode is electrically connected in parallel with the discharge switch. In further embodiments not shown, no freewheeling diode is provided in the circuit.

[0025] To initiate the capacitor discharge process, the control unit 150 closes the discharge switch 230 via the connecting line 201, causing a high-intensity discharge current from the capacitor 300 to flow through the excitation coil 100. The rapidly rising discharge current induces an excitation magnetic field, which permeates the squirrel-cage rotor 90 and, in turn, induces a circular electrical secondary current in the squirrel-cage rotor 90. This developing secondary current, in turn, generates a secondary magnetic field that opposes the excitation magnetic field, causing the squirrel-cage rotor 90 to experience a Lorentz force repelling the excitation coil 100, which drives the driving element 60 toward the receptacle 20 and the fastening element 30 received therein.As soon as the piston rod 80 of the driving element 60 hits a head (not further specified) of the fastening element 30, the fastening element 30 is driven into the substrate by the driving element 60. Excess kinetic energy of the driving element 60 is absorbed by a braking element 85 made of a resilient and / or damping material, such as rubber, by the driving element 60 moving with the piston plate 70 against the braking element 85 and being decelerated by the braking element 85 until it comes to a standstill. The driving element 60 is then returned to the position ready for installation by a return device (not further specified).

[0026] The capacitor 300, in particular its center of gravity, is arranged behind the driving element 60 on the setting axis A, whereas the receptacle 20 is arranged in front of the driving element 60. With respect to the setting axis A, the capacitor 300 is therefore axially offset from the driving element 60 and radially overlapping with the driving element 60. This allows, on the one hand, a short length of the discharge lines 210, 220 to be achieved, which reduces their resistance and thus increases the efficiency of the drive. On the other hand, a short distance between the center of gravity of the setting tool 10 and the setting axis A can be achieved. This minimizes tilting moments in the event of a recoil of the setting tool 10 during a driving process. In an embodiment not shown, the capacitor is arranged around the driving element.

[0027] The electrodes 310, 320 are arranged on opposite sides of a carrier foil 330 wound around a winding axis, for example by metallizing the carrier foil 330, in particular by vapor deposition, wherein the winding axis coincides with the setting axis A. In embodiments not shown, the carrier foil with the electrodes is wound around the winding axis in such a way that a passage remains along the winding axis. In this case in particular, the capacitor is arranged around the setting axis, for example. The carrier foil 330 has a film thickness of between 2.5 µm and 4.8 µm at a charging voltage of the capacitor 300 of 1500 V, and a film thickness of, for example, 9.6 µm at a charging voltage of the capacitor 300 of 3000 V. In embodiments not shown, the carrier foil is in turn composed of two or more individual foils layered one on top of the other. The electrodes 310, 320 have a sheet resistance of 50 Ohm / □.

[0028] A surface of the capacitor 300 has the shape of a cylinder, in particular a circular cylinder, whose cylinder axis coincides with the setting axis A. The height of this cylinder in the direction of the winding axis is essentially as large as its diameter measured perpendicular to the winding axis. A low height-to-diameter ratio of the cylinder achieves a low internal resistance with a relatively high capacitance of the capacitor 300 and, not least, a compact design of the setting tool 10. A low internal resistance of the capacitor 300 is also achieved by a large conductor cross-section of the electrodes 310, 320, in particular by a high layer thickness of the electrodes 310, 320, whereby the effects of the layer thickness on a self-healing effect and / or a service life of the capacitor 300 must be taken into account.

[0029] The capacitor 300 is mounted on the rest of the setting tool 10 in a dampened manner by means of a damping element 350. The damping element 350 dampens movements of the capacitor 300 relative to the rest of the setting tool 10 along the setting axis A. The damping element 350 is arranged on the end face 360 of the capacitor 300 and completely covers the end face 360. As a result, the individual windings of the carrier foil 330 are evenly loaded by a recoil of the setting tool 10. The electrical contacts 370, 380 protrude from the end face 360 and penetrate the damping element 350. For this purpose, the damping element 350 each has a recess through which the electrical contacts 370, 380 protrude. The connecting lines 301 each have a relief and / or expansion loop (not shown in detail) to compensate for relative movements between the capacitor 300 and the rest of the setting device 10.In embodiments not shown, a further damping element is arranged on the capacitor, for example, on its end face facing away from the receptacle. The capacitor is then preferably clamped between two damping elements, i.e., the damping elements rest against the capacitor with a preload. In further embodiments not shown, the connecting lines have a stiffness that continuously decreases with increasing distance from the capacitor.

[0030] In Fig. 2 Another embodiment of a hand-held setting tool 410 for driving fasteners along a setting axis A' into a substrate (not shown) is shown. Analogous to the Fig. 1 In the setting tool 10 shown, the setting tool 410 comprises a receptacle 420 designed as a bolt guide, in which a fastening element 430 designed as a nail is received, a magazine 440 in which the fastening elements are received individually or in the form of a fastening element strip 450, a driving element 460 which comprises a piston plate 470 and a piston rod 480, a guide cylinder 495 in which the piston plate 470 is guided, a braking element 485 and a stop element 580.

[0031] The driving element 460 is driven by a drive comprising a squirrel-cage rotor 490 arranged on the piston plate 470, an excitation coil 500, an annular soft-magnetic frame 505, a switching circuit (not shown), and a capacitor (also not shown). The setting tool 410 further comprises a housing 510 in which the drive is accommodated, a handle 520 with an actuating element 530 designed as a trigger, as well as other components (not shown), such as an electrical energy storage device or a power cable, a control unit, a trigger switch, a contact pressure switch, and electrical connecting lines connecting the control unit to the electrical energy storage device, the trigger switch, the contact pressure switch, the switching circuit, and the capacitor, respectively, and a reset device.

[0032] In the Fig. 2 In the illustrated position of the driving element 460 ready for insertion, the stop element 580 supports the driving element 460 against movement toward the excitation coil 500. The driving element 460 is spaced from the excitation coil 500 by forming an air gap 590 with a gap width of 0.05 mm and from the soft magnetic frame 505 by forming a further air gap 595 with a gap width of, for example, 0.5 mm. This prevents or mitigates an impact of the driving element 460 on the excitation coil 500, which may be additionally dampened by an air cushion between the driving element 460 and the excitation coil 500. The stop element 580 ensures a small gap width and thus a large repulsion force between the excitation coil 500 and the squirrel-cage rotor 490. The stop element 580 has a convex stop surface 585 facing the receptacle 420, which is arranged on the setting axis A'.The driving element 460 has a flat counter surface 465 facing away from the receptacle 420, which is also arranged on the setting axis A'. In embodiments not shown, the counter surface is convex, in particular crowned, instead of or in addition to the stop surface. In the embodiment shown in . Fig. 2 In the illustrated position of the driving element 460 ready for insertion, the stop surface 585 and the counter surface 465 abut one another. With respect to the insertion axis A', the stop element 580 is arranged radially within the excitation coil 500 and radially within the soft magnetic frame 505. The stop element 580 comprises a damper 581, which has the stop surface 585 and dampens the impact of the driving element 460 against the stop element 580.

[0033] The setting tool 410 works essentially the same as the one in Fig. 1illustrated setting tool 10. When the driving element 60 is returned by the return device into the position ready for setting, the counter surface 465 rests or strikes the stop surface 585. Mechanical stress on the excitation coil 500 and / or the soft magnetic frame 505 is reduced due to the respective distance of the excitation coil 500 or the soft magnetic frame from the driving element 460.

[0034] Preferably, the piston rod 480 passes through the piston plate 470 and has the counter surface 465. The piston rod 480 is made of an impact-resistant material, such as steel, so that wear of the piston rod 480 is reduced upon repeated impact with the fastening elements 430 and / or upon likewise repeated impact with the stop element 580. The piston plate 470 is protected from impacts by the arrangement according to the invention and is made of a low-density material, such as aluminum, so that the overall mass of the driving element 460 and thus the energy required for its acceleration is reduced.The stop element 580 is preferably rod-shaped and preferably consists of an impact-resistant material such as steel and is supported, in particular fastened, to the housing 510 directly or indirectly, for example by means of a reinforcement 506 of the soft magnetic frame 505 and / or a fastening element 507, for example a screw or screw nut.

[0035] The invention has been described using a number of exemplary embodiments, some of which are shown in the drawings and some of which are not shown. The individual features of the various exemplary embodiments can be used individually or in any combination, provided they do not contradict one another. It should be noted that the setting tool according to the invention can also be used for other applications.

Claims

1. Setting tool (410) for driving fastening elements (430) into a substrate, in particular a hand-held setting tool, comprising a holder (420), which is provided for holding a fastening element, a drive-in element (460), which is provided for transferring a fastening element held in the holder into the substrate along a setting axis, a drive, which is provided for driving the drive-in element toward the fastening element along the setting axis, characterized in that the drive comprises an excitation coil (500) which is flowed through by current and generates a magnetic field which accelerates the drive-in element onto the fastening element, and a stop element (580), which supports the drive-in element (460) against movement toward the excitation coil when the drive-in element is in a ready-to-set position, the drive-in element being spaced apart from the excitation coil in the ready-to-set position .

2. Setting tool according to Claim 1, wherein an air gap (590) is formed between the drive-in element and the excitation coil when the drive-in element is in a ready-to-set position.

3. Setting tool according to Claim 2, wherein the air gap has a gap width which is between 0 and 0.5 mm, in particular between 0.01 mm and 0.2 mm, in particular between 0.02 mm and 0.1 mm.

4. Setting tool according to one of the preceding claims, wherein the stop element has a stop surface (585) that faces the holder and the drive-in element has a counter surface (465) that faces away from the holder, and wherein the stop surface and the counter surface lie against one another when the drive-in element is in a ready-to-set position.

5. Setting tool according to Claim 4, wherein the stop surface and / or the counter surface is arranged on the setting axis or around the setting axis.

6. Setting tool according to either of Claims 4 and 5, wherein the stop surface and / or the counter surface is convex, in particular spherical.

7. Setting tool according to one of the preceding claims, wherein a projection of the stop element in the direction of the setting axis is arranged radially inside a projection of the excitation coil in the direction of the setting axis.

8. Setting tool according to Claim 7, wherein the stop element is arranged radially inside the excitation coil with respect to the setting axis.

9. Setting tool according to one of the preceding claims, wherein the drive comprises a soft-magnetic frame (505) on which the excitation coil is arranged, wherein the excitation coil is embedded in particular in the soft-magnetic frame.

10. Setting tool according to Claim 9, wherein the drive-in element is spaced apart from the soft-magnetic frame in the ready-to-set position.

11. Setting tool according to either of Claims 9 and 10, wherein a further air gap (595) is formed between the drive-in element and the soft-magnetic frame when the drive-in element is in the ready-to-set position.

12. Setting tool according to one of the preceding claims, wherein the soft-magnetic frame is formed in a ring shape, and wherein a projection of the stop element in the direction of the setting axis is arranged radially inside a projection of the soft-magnetic frame in the direction of the setting axis.

13. Setting tool according to Claim 12, wherein the stop element is arranged radially inside the soft-magnetic frame with respect to the setting axis.

14. Setting tool according to one of the preceding claims, wherein the stop element and / or the drive-in element comprises a damper (581) which has the stop surface or the counter surface.

15. Setting tool according to Claim 14, wherein the damper dampens striking of the drive-in element against the stop element.