EP2397274A2 - Electrically actuated bolt setting device - Google Patents

Abstract

The driver (1) has an electric drive motor (2) that is driven by an electrical power supply device (20). The electrical power supply device is connected with the bolt driver through a safety mechanism (25), where an intermediate storage (8) is automatically transferred from an energy storage state into an idle state when the electric power supply device is disconnected from the bolt driver. The intermediate storage includes a spring element (10) that is tensioned to store drive energy of the power supply device when the power supply device is connected with the bolt driver.

Description

Technical area

The invention relates to an electrically actuable bolt setting device comprising an electric drive motor which is drivable by an electrical power supply device and outputs drive energy to a buffer, which can buffer the drive energy and deliver abruptly in a setting process to set a bolt.

State of the art

The electrically actuable bolt setting device is preferably a hand-held tacker, as described in the German Offenlegungsschriften DE 10 2006 000 517 A1 and DE 10 2006 035 460 A1 is disclosed. That in the German publication DE 10 2006 035 460 A1 disclosed tackler comprises in addition to a trigger switch at least one further switching means for the locking device, via which a locking device is independent of the trigger switch in a release position can be transferred. By this measure, it is possible to transfer a drive spring element independent of an actuation of the trigger switch by transferring the locking device in the release position in its relaxed position, so that they are not fatigued for prolonged disuse. The further switching means may be a time switching means or a main switch, via which the tacker is switched on and off, so that when switching off the tacker on this main switch, the drive spring element is automatically transferred by operating the locking device in the relaxed position.

Presentation of the invention

The object of the invention is to increase the safety in the operation of electrically actuated bolt devices on.

The object is achieved with an electrically actuable bolt setting device, which comprises an electric drive motor, which can be driven by an electrical power supply device and delivers drive energy to an intermediate store, which can temporarily store the drive energy and deliver it abruptly during a setting process in order to set a bolt, in that the bolt setting device comprises a safety mechanism by means of which the electric power supply device can be coupled or coupled to the bolt setting device such that the buffer is automatically transferred from a memory state into a defined idle state when the electric power supply device is disconnected from the bolt setting device. By the safety mechanism of the cache is then transferred to its defined idle state, if the electrical power is deliberately interrupted by the user or by an error. The transfer of the buffer into the idle state is carried out automatically by the security mechanism according to the invention.

A preferred embodiment of the bolt-firing device is characterized in that the electrical power supply device comprises an accumulator. The electrically actuable bolt setting device is preferably operated with a rechargeable battery, which is also referred to as a rechargeable battery.

A further preferred embodiment of the bolt setting tool is characterized in that the buffer comprises a drive spring element that can be tensioned by the electric drive motor to store drive energy, and that, when the electrical power supply device is disconnected from the bolt setting device, automatically relaxed so that the cached drive energy is reduced in a controlled manner. The drive spring element can be tensioned, for example, via a threaded spindle and a spindle nut guided against rotation on the threaded spindle. In this case, a rotational movement of the threaded spindle generated by the electric drive motor is converted into a linear movement or translational movement of the spindle nut. Alternatively or additionally, gas accumulators and / or flywheels can be used as temporary storage.

A further preferred embodiment of the bolt-firing apparatus is characterized in that the safety mechanism comprises a latch, which holds the latch for latching drive energy in its memory state and automatically releases the latch when the electrical power supply is disconnected from the bolt-firing device, so that the latch in its defined idle state is transferred. The pawl can be a conventional pawl of a locking device, as used in known bolt guns. But it can also be an additional latch. It is essential that the pawl is part of the safety mechanism. The pawl is preferably mechanically coupled to the power supply device such that the pawl is automatically moved from a blocking position to a release position when the power supply device is removed or removed.

A further preferred embodiment of the bolt setting tool is characterized in that the safety mechanism comprises an electromechanical actuator, which automatically unlocks a locking device, which holds the buffer in its storage state, when the electrical power supply device is disconnected from the bolt setting device. The electromechanical actuator includes, for example, a magnet or an electrically operated wrap spring.

A further preferred exemplary embodiment of the bolt setting tool is characterized in that the bolt setting device comprises a coupling and / or braking device in order to reduce the buffered drive energy in a controlled manner when the buffer is transferred from its storage state into its defined idle state. The clutch and / or brake device comprises, for example, a clutch and / or brake pad, which acts on a pinion, or a centrifugal brake or clutch. As a braking device and the electric drive motor of the bolt gun can be used.

A further preferred exemplary embodiment of the bolt-firing apparatus is characterized in that the safety mechanism comprises at least one safety switch that short-circuits phases of the electric drive motor in order to reduce cached drive energy in a controlled manner when the buffer is transferred from its memory state into its defined idle state. By shorting the phases, an induction voltage in the drive motor can be reduced. This leads to a current flow through the phases, whereby a magnetic field is generated counteracts the acceleration during the dismantling of the cached drive energy.

A further preferred embodiment of the bolt-firing device is characterized in that the safety switch is designed as a self-conducting electronic switch, in particular as a J-Fet. Due to the self-conductive electronic switch, the phases or windings of the electric motor are short-circuited even in the currentless case. This provides the advantage that the safety switch when transferring the buffer to its idle state without an explicit control by electronics. The safety switch is opened by the electronics only when the bolt-firing device is put into operation and with the electrical power installed in order to allow normal operation of the bolt-firing device. As an alternative to electronic switches, mechanical relays can also be used.

A further preferred embodiment of the bolt-firing device is characterized in that the electric drive motor is designed as an electrically commutated electric motor. This is preferably a brushless DC motor, which is also referred to as BLDC (brushless direct current) electric motor.

A further preferred embodiment of the bolt-firing device is characterized in that the electric drive motor comprises three phases and is driven by free-wheeling diodes by a 6-pulse bridge or B6 bridge or 3-phase motor bridge circuit, referred to below as a bridge rectify a voltage generated when breaking down the cached drive power. The bridge comprises six semiconductor elements, each comprising a transistor and a freewheeling diode, which are connected in parallel.

Figur 1

eine vereinfachte Darstellung eines Bolzensetzgeräts gemäß verschiedenen Ausführungsbeispielen;

Figur 2

ein elektrisches Schaltbild eines elektrischen Antriebsmotors des Bolzensetzgeräts aus Figur 1 und

Figur 3

eine Steuerung des elektrischen Antriebsmotors aus Figur 2 gemäß einem weiteren Ausführungsbeispiel.

Further advantages, features and details of the invention will become apparent from the following description in which various embodiments are described in detail. Show it:

FIG. 1

a simplified illustration of a bolt gun according to various embodiments;

FIG. 2

an electrical diagram of an electric drive motor of the bolt gun from FIG. 1 and

FIG. 3

a control of the electric drive motor FIG. 2 according to a further embodiment.

embodiments

The bolt setting device according to the invention is designed, for example, as a hand-held tacking device, as shown in FIGS FIGS. 1 to 4 or 1 to 2 and the corresponding descriptions of the German patents DE 10 2006 000 517 A1 and DE 10 2006 035 460 A1 is disclosed.

In FIG. 1 Such a bolt gun 1 is shown greatly simplified according to various embodiments of the invention. The bolt setting device 1 comprises a spring as a drive spring element 10 and is therefore also referred to as a spring nailer.

The spring 10 is a buffer 8 and is tensioned by an electric drive motor 2, which is controlled by a controller 3. The electric drive motor 2, which is designed as an electric motor, drives a threaded spindle 14 via a belt drive 5. About a non-rotatably guided on the threaded spindle 14 spindle nut 12, a rotational movement of the threaded spindle 14 is converted into a linear movement of the spindle nut 12.

The spring 10 is stretched over the linear movement of the spindle nut 12. At the end of a clamping movement, the spindle nut 12 locks with a pawl 18 of a locking device 16 and is thereby held in the cocked position, while the spindle nut 12 is driven by the electric motor 2 in the reverse direction back to its original position. The spring 10 is held by the pawl 18 in its cocked position until the user opens the latch 18 by pressing a trigger and thus triggers a bolt setting process. After setting the bolt, the spring 10 is stretched by means of the electric motor 2 again.

The spring 10 is thus tensioned by the spindle nut 12 on the threaded spindle 14 performs a reciprocating motion, wherein the electric motor 2 is energized for a certain time in one direction and then back in the opposite direction. The energization of the electric motor is controlled by the electronic control 3, wherein the controller 3 energized the electric motor 2 in one direction until the spindle nut 12 triggers a control signal by reaching the respective end position, for example, when driving over the pawl 18. By the control signal is the controller 3 informed that the respective Final position has been reached. Then, the energization of the electric motor 2 can be turned off by the controller 3 and the electric motor 2 are energized in the opposite direction.

At the in FIG. 1 illustrated bolt setting device 1 is used for electrical power supply indicated by a rectangle electrical power supply device 20, which is designed as an accumulator 22, short battery. The battery 22 is coupled via a safety mechanism 25 with the latch 8, that the spring 10 is automatically relaxed when the battery 22 is removed.

For the sake of simplicity, in FIG. 1 three different embodiments indicated how the safety mechanism 25 can be performed. The three embodiments can each be used alone in a bolt setting device 1, but can also be combined with each other as desired.

By a line 26 is indicated that the pawl 18 of the locking device 16 may be mechanically coupled to the battery 22 so that the pawl 18 is automatically moved from its illustrated blocking position to a release position in which the spring 10 automatically relaxes. When the pawl 18 is moved by removing the battery 22 in its release position, then the spring 10 drives the electric drive motor 2 when relaxing on the spindle nut 12, the threaded spindle 14 and the belt drive 5.

The electric drive motor 2 is embodied as a brushless direct current (BLDC) electric motor, which is also referred to as a brushless DC motor, and comprises a rotor with permanent magnets. When relaxing the spring 10, the rotor of the electric motor 2 is rotated. In this case, the permanent magnets of the rotor are accelerated, whereby in a stator of the electric motor 2, a voltage is induced. This induction voltage is reduced by the short circuit of phases of the electric motor 2.

This in turn leads to a current in the phases and generates in the electric motor 2 a magnetic field which counteracts the acceleration. As a result, a counter force is generated by the electric motor 2, which counteracts the spring force of the spring 10 when relaxing and prevents high acceleration. This can be achieved in a simple manner, that the spring energy is automatically reduced slowly when relaxing the spring 10 by the electric motor 2.

The short circuiting of the phases is effected by a safety switch 30, which, as indicated by a line 31, is coupled to the battery 22. Upon removal of the battery 22, the safety switch 30 is automatically transferred so that the phases of the electric motor 2 are short-circuited. When inserting the battery 22, the safety switch 30 is opened again. In FIG. 1 the safety switch 30 is shown in its open position.

The safety mechanism 25 may alternatively or additionally comprise a coupling and / or braking device 28, which, as indicated by a line 29, is coupled to the battery 22. The coupling and / or braking device 28 cooperates with a pulley of the belt drive 5. The coupling 29 is designed so that the coupling and / or braking device 28 brakes the threaded spindle 14 via the belt drive 5 when the spring 10 is automatically released after the battery 22 has been removed. During normal operation of the bolt-firing device 1, the clutch and / or brake device 28 develops no braking action. By inserting the battery 22, the coupling and / or braking device 28 is automatically decoupled from the belt drive 5.

In FIG. 2 is an electric drive motor 40 shown in simplified form in the form of an electrical circuit diagram. The electric drive motor 40 corresponds to the in FIG. 1 The electric drive motor 40 is designed as a BLDC (brushless direct current) electric motor, which is also referred to as a brushless DC motor or electrically commutated electric motor.

The brushless DC motor 40 comprises a rotor with permanent magnets and a stator with three windings or phases 41, 42, 43. The windings 41 to 43 are connected via lines 44, 45, 46 to a controller 50. By a symbol 48 a grounding sign is indicated. By another arrow-shaped symbol 49 is a plus terminal of the accumulator (20 in FIG. 1 ) indicated.

The controller 50 is designed as a bridge with six semiconductor elements 51 to 56. Each semiconductor element 51 to 56 comprises a transistor, in particular a field-effect transistor, and a freewheeling diode connected in parallel therewith and in particular integrated in the transistor. Via the semiconductor elements 51 to 56, the windings 41 to 43 are controlled in dependence on the position of the rotor so that a rotating field is generated. The position of the rotor is detected, for example, by Hall sensors or by sensorless methods.

In normal operation of the electric drive motor 40, a transistor of in FIG. 2 upper row of the semiconductor elements 51, 53, 55 and the lower row of the semiconductor elements 52, 54, 56 are turned on, so that the current always flows through two windings. The third winding is then de-energized. Due to the interaction with the permanent magnets of the rotor, a torque then arises via the generated magnetic flux.

According to a further aspect of the invention, when the spring (10 in FIG FIG. 1 ) generated voltage of the electric drive motor 40 used for braking, while the generated voltage of the motor is proportional to the speed and is rectified via the freewheeling diodes of the bridge, which is also referred to as a bridge. Since the generated voltage is sufficient even at a comparatively low number of revolutions to supply the electronics, the latter can then cause a braking of the electric drive motor 40 by switching on the lower and / or upper field-effect transistors.

In FIG. 3 is a similar control 60 as in FIG. 2 represented for the same electric drive motor. The controller 60 includes two additional safety switches 61, 62. Depending on the required braking force, a single safety switch 61, 62 may be sufficient.

The safety switch 61 is connected between two connection points of the lines 44 and 45. The safety switch 62 is connected between two connection points of the lines 45, 46. The two safety switches 61, 62 are designed as self-conducting electronic switches, for example as a J-Fet.

The peculiarity of this self-conductive electronic safety switch 61, 62 is that the safety switches 61, 62 are conductive without an explicit control by an electronic system. This causes the windings (41 to 43 in FIG. 2 ) of the electric drive motor are short-circuited even in the currentless case and are only actively switched off by a corresponding control in normal operation. As an alternative to the electronic safety switches 61, 62 and mechanical relays can be used.

By deliberately short-circuiting the phases or windings of the electric drive motor by means of the safety switches 61, 62, the voltage induced by acceleration of the permanent magnets of the rotor voltage can be reduced. The resulting current flow in the phases or windings generates a Magnetic field in the electric drive motor 40, which counteracts the acceleration when relaxing the spring. With this counterforce, the cached drive energy of the spring can be slowly reduced.

Claims (10)

Electrically actuated bolt setting tool (1) which comprises an electric drive motor (2; 40) which can be driven by an electrical energy supply device (20) and delivers drive energy to a buffer store (8) which can temporarily store the drive energy and deliver it abruptly during a setting process, to set a bolt, characterized in that the bolt setting device (1) comprises a safety mechanism (25) by which the electrical power supply device (20) with the bolt setting device (1) is coupled or coupled, that the latch (8) automatically off a memory state is transferred to a defined idle state when the electrical power supply device (20) is separated from the bolt setting device (1). Bolt setting tool according to claim 1, characterized in that the electrical energy supply device (20) comprises an accumulator (22). Bolt setting tool according to one of the preceding claims, characterized in that the intermediate store (8) comprises a drive spring element (10) which can be tensioned by the electric drive motor (2; 40) in order to store drive energy, and this if the electrical power supply device ( 20) is separated from the bolt setting device (1) is automatically relaxed so that the cached drive energy is reduced in a controlled manner. Bolt setting tool according to one of the preceding claims, characterized in that the safety mechanism (25) comprises a pawl (18) which holds the buffer memory (8) for storing drive energy in its storage state and automatically releases the latch (8) when the electrical Power supply device (20) is separated from the bolt setting device (1), so that the buffer (8) is transferred to its defined idle state. Bolt setting tool according to one of the preceding claims, characterized in that the safety mechanism (25) comprises an electromechanical actuator, a lock device (16), which holds the latch (8) in its storage state, automatically unlocked when the electrical power supply device (20) is disconnected from the bolt setting device (1). Bolt setting tool according to one of the preceding claims, characterized in that the bolt setting device (1) comprises a coupling and / or braking device (28) to reduce the cached drive energy controlled when the latch (8) is transferred from its storage state to its defined idle state , Bolt setting tool according to one of the preceding claims, characterized in that the safety mechanism (25) comprises at least one safety switch (30; 61,62) which shorts phases (41,42,43) of the electric drive motor (40) in order to reduce cached drive energy in a controlled manner when the latch (8) is transferred from its memory state to its defined idle state. Bolt setting tool according to claim 7, characterized in that the safety switch (30; 61,62) is designed as a self-conducting electronic switch, in particular as a J-Fet. Bolt setting tool according to one of the preceding claims, characterized in that the electric drive motor (2; 40) is designed as an electrically commutated electric motor. Bolt setting tool according to one of the preceding claims, characterized in that the electric drive motor (2; 40) comprises three phases (41-43) and is driven by a bridge with freewheeling diodes which rectify a voltage generated during breaking down of the cached drive energy.

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