Control circuit for activating and deactivating an electrically operated hand tool, and hand tool having a control circuit of this type
The control circuit with herringbone-patterned contact tracks and movable contacts addresses the issue of vibration-induced contact loss and inrush currents, ensuring stable and efficient operation of electrically operated hand tools.
Patent Information
- Authority / Receiving Office
- WO · WO
- Patent Type
- Applications
- Current Assignee / Owner
- Filing Date
- 2025-07-25
- Publication Date
- 2026-04-02
AI Technical Summary
Existing control circuits for electrically operated hand tools are susceptible to contact loss due to vibrations and do not provide a standby power supply, leading to inefficiencies and increased wear.
A control circuit with continuous first and transverse second contact tracks featuring herringbone patterns and movable contacts that reduce wear and collect particles, ensuring stable electrical connections and managing inrush currents.
The solution provides stable electrical connections resistant to vibrations, reduces wear, and effectively manages inrush currents, enhancing the reliability and efficiency of the hand tool operation.
Smart Images
Figure EP2025071498_02042026_PF_FP_ABST
Abstract
Description
[0001] Marquardt GmbH
[0002] P 593 PCT KN
[0003] Control circuit for activating and deactivating an electrically operated hand tool and a hand tool with such a control circuit
[0004] Description:
[0005] The invention relates to a control circuit for activating and deactivating an electrically operated hand tool and a hand tool with such a control circuit.
[0006] The state of the art reveals a multitude of ways in which the energy or power supply, particularly on an electrically operated hand tool, can be activated and deactivated.
[0007] In simple cases, a standard switch or push button can be used. However, if activation and deactivation are not to be achieved by a separate switch or push button, it is also known to implement activation and deactivation using a contact wire or contact plate, which is connected to a control element (e.g., for speed control) and which, after a predetermined travel distance, comes into contact with a counterpart element when the control element is actuated, thereby establishing an electrically conductive connection.
[0008] A disadvantage of this design is that such contact wires or plates must be soldered or otherwise attached to the control element and a circuit and electrically connected. Furthermore, the inherent elasticity of both the contact wire or plate and the mating element can lead to a loss of contact and a corresponding brief interruption of the power supply when subjected to vibrations.
[0009] Furthermore, the circuits known in the prior art can only establish or interrupt a power supply, so that the power supply, for example a standby circuit, is usually not provided for and also not possible.
[0010] The invention is therefore based on the objective of overcoming the aforementioned disadvantages and providing a control circuit for activating and deactivating an electric hand tool that is less susceptible to disturbances caused by vibration and can be manufactured cost-effectively.
[0011] This problem is solved by the combination of features according to claim 1.
[0012] According to the invention, a control circuit for activating and deactivating an electrically operated hand tool, such as a drill or the like, is proposed. The control circuit comprises a first contact track extending continuously in a longitudinal direction from a starting point to an endpoint and connected to a circuit input, and a second contact track extending in a transverse direction orthogonal to the longitudinal direction, parallel to the first contact track, and consisting of three contact surfaces arranged successively in a row and insulated from one another. For example, the control circuit can provide a circuit carrier, in particular a printed circuit board, on which the first and second contact tracks are directly formed and arranged.For this purpose, the contact tracks can be formed on the circuit carrier, for example, by etching or other known methods. Regarding the contact surfaces of the second contact track, it should be noted that the first contact surface of the row is connected to a first circuit output. Furthermore, a second contact surface of the row is connected to a second circuit output, and / or a third contact surface of the row is connected to a third circuit output. As mentioned below, the first circuit output can be used to connect a standby circuit, while the second and / or third circuit output can be used to connect an actuator control for controlling an actuator of the hand tool.In addition to the two contact tracks, the control circuit also provides a movable contactor between the start and end points, which has at least one first contact for contacting the first contact track and at least one second contact for contacting the second contact track. The contactor can be designed as a sliding or friction contact to slide over or along the contact tracks. In particular, both the at least one first contact and the at least one second contact extend parallel to each other and form the prongs of a contact comb, which are convex at the contact surface where they are in contact with the respective contact track.According to the invention, the receiver is further configured to electrically connect the first contact track with the second contact track, such that, depending on the position of the receiver in the longitudinal direction along the contact tracks, the first contact track is electrically conductively connected to the first contact surface or the second contact surface and / or the third contact surface of the second contact track.
[0013] According to the invention, the first contact track is further divided in the transverse direction into a first section and a second section, which are electrically connected to each other. In the first section, the first contact track is formed by a plurality of (first) ribs that are parallel to each other and form a predetermined angle with the longitudinal direction. Each of these ribs is electrically connected to the second section and / or has a free end. Preferably, the ribs transition directly into the second section. Each rib can have a base, with the respective rib transitioning into the second section at the base and the free end located on a side of the rib facing away from the second section.The first section has a herringbone pattern formed by the ridges, the angled design of which ensures that the sensor sliding over the ridges is always in electrical contact with at least one, and preferably two, ridges. It has been shown that the individual ridges and the herringbone pattern reduce wear on the contact track and, in particular, the effects of such wear. Building upon this, a receiving space is formed between each pair of ridges, designed to collect particles generated by abrasion along the first contact track and / or particles, such as dust, moved by the sensor's movement along the first contact track.Additionally or alternatively, the receiving space can be designed to transport the particles towards the free ends of the webs and thus out of the receiving space and out of the contact path, so that the electrical contact is not hindered or disturbed by the particles.
[0014] Building on this, it can further be provided that the receiver has two first contacts, of which a first main contact is designed to contact the first section of the first contact track, and of which a first secondary contact is designed to contact the second section of the first contact track, so that the main contact can slide uninterrupted over the webs in the first section of the first contact track and the secondary contact can slide uninterrupted over the second section of the first contact track.
[0015] In order to enable a clear separation between the first circuit output and the second or third circuit output, and thus to cleanly separate an activated state and a deactivated state, it can further be provided that an electrically non-conductive free space is provided along the longitudinal direction between the first contact surface and the second contact surface, which is designed to accommodate at least one second contact, so that the sensor is electrically connected neither to the first contact surface nor to the second contact surface when transitioning from the first contact surface to the second contact surface.
[0016] Analogous to the first contact track, the second contact track can also be divided transversely into a first section and a second section, which are electrically connected to each other. The first contact surface and / or the second contact surface and / or the third contact surface of the second contact track are accordingly formed in the first section by a plurality of (second) ribs parallel to each other and forming a predetermined angle with the longitudinal direction. Each of these ribs is electrically connected to the second section and / or each has a free end. Preferably, it is further provided that the ribs transition directly into the second section. Thus, each rib can have a base, with the respective rib transitioning into the second section at the base and the free end located on a side of the rib facing away from the second section.Similarly, the herringbone pattern formed by the bridges can reduce wear caused by contact with the consumer and, in particular, the effects of wear on the contact path.
[0017] Analogous to the first contact path, it is particularly preferred that the second contact path also has a receiving space formed between each pair of webs. This receiving space is designed to collect particles generated by abrasion along the second contact path and / or particles, such as dust, that are moved along the second contact path by the movement of the sensor. Additionally or alternatively, the receiving space can be designed to transport the particles towards the free ends of the webs and thus out of the receiving space and out of the contact path, so that the electrical contact is not obstructed or disrupted by the particles.
[0018] If ridges are provided on both the first and the second contact track, their free ends preferably point away from each other, so that the particles in the receiving spaces of the first contact track can be transported in a first direction and the particles in the receiving spaces of the second contact track can be transported in an opposite direction.
[0019] Assuming such a division of the second contact track, the receiver can have two second contacts, one of which is a second main contact to contact the first section of the second contact track, and one of which is a second secondary contact to contact the second section of the second contact track, so that the main contact can slide uninterrupted over the webs in the first section of the second contact track and the secondary contact can slide over the second section of the second contact track.
[0020] To reduce high inrush currents or to manage them effectively, the second contact surface in the second section can be designed with a second projection extending longitudinally to the third contact surface, while the third contact surface in the first section forms a third projection extending longitudinally to the second contact surface. The second and third projections extend longitudinally without contact until they reach a common, transverse imaginary line where contact re-entry occurs. When the sensor moves or is actuated from the starting point to the end point, initially only the associated secondary contact is in contact with the second contact track. This secondary contact is then replaced by the primary contact at the imaginary line, and the secondary contact also comes back into contact with the second contact track at the end of the third projection.
[0021] Based on this, or by applying a different geometry, it can be provided that an electrically non-conductive transition space is provided along the longitudinal direction between the second contact surface and the third contact surface, which is designed to alternately receive one of the second contacts, so that the receiver is electrically connected step by step to the third contact surface when transitioning from the second contact surface to the third contact surface.
[0022] The receiver can have a fastening section and a spring section, through which at least one first contact and at least one second contact are formed, such that at least one first contact and at least one second contact can be pressed spring-elastically against the respective contact track.
[0023] Another aspect of the invention relates to a hand tool with an electrically operated actuator, an actuator controller for controlling the actuator, a standby circuit, and a control circuit according to the invention. In such a hand tool, the standby circuit is electrically connected to the first circuit output, and the actuator controller is electrically connected to the second and / or third circuit output.
[0024] The features disclosed above can be combined in any way, provided that this is technically possible and that they do not contradict each other.
[0025] Other advantageous embodiments of the invention are characterized in the dependent claims or are described in more detail below together with the description of the preferred embodiment of the invention with reference to the figures. The figures show:
[0026] Fig. 1 shows a circuit carrier with the contact tracks of a control circuit formed on it;
[0027] Fig. 2 shows a sensor belonging to a control circuit. The figures are schematic examples. Identical reference numerals in the figures indicate identical functional and / or structural features. The circuit carrier shown in Figure 1 and the sensor 30 shown in Figure 2 can both belong to a control circuit 1.
[0028] It is essential that the control circuit 1 shown in Figure 1 – except for the receiver 30 – serves to activate and deactivate an electrically operated hand tool and for this purpose has a first contact track 10 and a second contact track 20 running parallel to it. The first contact track 10 extends continuously in a longitudinal direction X from a starting point 11 to an endpoint 12 and is connected to a circuit input 40. The second contact track 20 is adjacent to the first contact track 10 in a transverse direction Y orthogonal to the longitudinal direction X and extends parallel to the first contact track 10 in the longitudinal direction.Furthermore, the second contact track 20 is formed from three contact surfaces 21, 22, 23 arranged one after the other in a row and insulated from each other, of which a first contact surface 21 of the row is connected to a first circuit output 41, a second contact surface 22 to a second circuit output 42, and a third contact surface 23 of the row to a third circuit output 43.
[0029] For example, the pickup 30 shown in Figure 2 is movable or displaceable between start point 11 and end point 12, wherein the pickup 30 has two first contacts 31 and two second contacts 32, whose sliding paths are shown as dashed lines on the contact paths 10, 20.
[0030] Both contact tracks 10, 20 are divided into two sections in the transverse direction Y, with herringbone-patterned ribs 14, 24 provided in the respective first section, which are in contact with the respective second section. As can be seen from the sliding paths of the contacts 31, 32 of the receiver, a first main contact 31A is provided, which slides along the ribs 14 of the first contact track 10, i.e., along the first ribs 14, and a first secondary contact 31B, which slides along the first contact track 10 in the second section. Similarly, a second main contact 32A is provided, which slides along the ribs 24 of the second contact track 20, i.e., along the second ribs 24, and a second secondary contact 32B, which slides along the second contact track 20 in the second section. This results in a reduction of mechanical wear.
[0031] In addition, particles generated by abrasion on the contact tracks 10, 20, as well as further particles which are moved by the pickup 30 along the contact tracks 10, 20, are transported by the pickup 30 into receiving spaces defined between the webs 14, 24, so that the particles do not interfere with the movement of the pickup 30 and the electrical contact of the pickup 30 or of the respective main contact 31 A, 31 B with the contact tracks 10, 20.
[0032] If the movement of the receiver conveys 30 more particles into the receiving chambers, the particles present in the receiving chambers are conveyed to the respective free ends of the webs 14, 24 and thus out of the contact track 10, 20 and the contact tracks 10, 20 are thus automatically cleaned.
[0033] When the sensor 30 moves or shifts from the starting point 11 to the end point 12, the sensor 30, through its contact with the first contact surface 21, initially contacts the circuit input 40 with the first circuit output 41, which can, for example, supply a standby circuit.
[0034] When the consumer reaches 30, the free space between the first contact surface
[0035] 21 and the second contact surface 22, the circuit input 40 is initially not contacted with any of the circuit outputs 41, 42, 43, thus creating a clean separation between the deactivated state, in which the first circuit output 41 is contacted, and the activated state, in which the second and / or third circuit output 42, 43 is contacted.
[0036] If the consumer 30 contacts the second contact surface 22 via the second main contact 32A and the second secondary contact 32B, the circuit input 40 is connected to the second circuit output 42, thereby supplying current or energy to an actuator control and initiating a short switch-on process, which is intended, for example, to reduce high inrush currents.
[0037] When the contactor 30 moves from the second contact surface 22 to the third contact surface 23, a transition space is formed by the longitudinally extending projections 25, 26 towards each other, through which first only the second auxiliary contact 32B, then only the second main contact 32A and then both the second auxiliary contact 32B and the second main contact 32A make electrical contact with the second contact track 20, thereby reducing the inrush current in the event of otherwise sudden full contact.
[0038] In order to ensure a permanent, good electrical contact during the movement of the receiver 30 from the starting point 11 to the end point 12, the receiver 30 has a fastening section 33 and a spring section 34, wherein in the spring section 34 the first main contact 31 A, the first secondary contact 31 B, the second main contact 32 A and the second secondary contact 32 B protrude as prongs of a contact comb and can be pressed spring-elastically against the contact tracks 10, 20.
[0039] * * * * *
Claims
Patent claims 1. Control circuit (1) for activating and deactivating an electrically operated hand tool, comprising a first contact track (10) which extends continuously in a longitudinal direction (X) from a starting point (11) to an end point (12) and is connected to a circuit input (40), a second contact track (20) which is adjacent to the first contact track (10) in a transverse direction (Y) orthogonal to the longitudinal direction (X) and extends parallel to the first contact track (10) in the longitudinal direction (X) and is formed from three contact surfaces (21, 22, 23) arranged successively in a row and insulated from each other, of which a first contact surface (21) of the row is connected to a first circuit output (41) and a second contact surface (22) to a second circuit output (42) and / or a third contact surface (23) of the row to a third circuit output (43),and with a sensor (30) movable between start point (11) and end point (12), which has at least one first contact (31) for contacting the first contact track (10) and at least one second contact (32) for contacting the second contact track (20), which is configured to electrically connect the first contact track (10) with the second contact track (20), such that, depending on the position of the sensor (30) along the contact tracks (10, 20), the first contact track (10) is electrically conductively connected to the first contact surface (21) or the second contact surface (22) and / or the third contact surface (23) of the second contact track (20), characterized in that the first contact track (10) extends in the transverse direction (Y) into a first, The first section is divided into a first section and a second section, which are electrically connected to each other, wherein the first contact path (10) in the first section is formed by a plurality of mutually parallel webs (14) enclosing a predetermined angle with the longitudinal direction (X), each of which is electrically connected to the second section and / or each has a free end, wherein a receiving space is formed between each pair of webs (14), which is designed to receive particles generated by abrasion along the first contact path (10) and / or particles moved by a movement of the sensor (30) along the first contact path (10) and / or to transport them away in the direction of the free ends of the webs (14).
2. Control circuit according to claim 1, wherein the receiver (30) has two first contacts (31), of which a first main contact (31 A) is configured to contact the first section of the first contact track (10), and of which a first secondary contact (31 B) is configured to contact the second section of the first contact track (10), so that the main contact (31 A) can slide continuously over the webs (14) in the first section of the first contact track (10) and the secondary contact (31 B) can slide continuously over the second section of the first contact track (10).
3. Control circuit according to claim 1 or 2, wherein an electrically non-conductive free space is provided along the longitudinal direction (L) between the first contact surface (21) and the second contact surface (22), which is configured to receive the at least one second contact (32), so that the sensor (30) upon transition from the first contact surface (21) to the The second contact surface (22) is not electrically connected to either the first contact surface (21) or the second contact surface (22).
4. Control circuit according to one of the preceding claims, wherein the second contact track (20) is divided in the transverse direction (Y) into a first section and a second section which are electrically connected to each other, and wherein the first contact surface (21) and / or the second contact surface (22) and / or the third contact surface (23) of the second contact track (20) in the first section is formed by a plurality of webs (24) parallel to each other and enclosing a predetermined angle with the longitudinal direction (X), each of which is electrically connected to the second section and / or each has a free end.
5. Control circuit according to the preceding claim, wherein a receiving space is formed between each pair of webs (24), which is configured to receive particles generated by abrasion along the second contact track (20) and / or particles moved by movement of the receiver (30) along the second contact track (20) and / or to transport them away in the direction of the free ends of the webs (24).
6. Control circuit according to one of claims 4 or 5, wherein the receiver (30) has two second contacts (32), of which a second main contact (32A) is configured to contact the first section of the second contact track (20), and of which a second secondary contact (32B) is configured to contact the second section of the second contact track (20), such that the main contact (32A) is continuously connected via the webs (24) in the first section of the second contact track (20) and the secondary contact (32B) can slide over the second section of the second contact track (20).
7. Control circuit according to one of claims 4 to 6, wherein the second contact surface (22) in the second section forms a second projection (25) extending in the longitudinal direction (L) to the third contact surface (23), wherein the third contact surface (23) in the first section forms a third projection (26) extending in the longitudinal direction (L) to the second contact surface (22), and wherein the second projection (25) and the third projection (26) extend without contact in the longitudinal direction up to a common line extending in the transverse direction (Y).
8. Control circuit according to one of the preceding claims, wherein an electrically non-conductive transition space is provided along the longitudinal direction (L) between the second contact surface (22) and the third contact surface (23), which is configured to alternately receive one of the second contacts (32), so that the receiver (30) is electrically connected stepwise to the third contact surface (23) during a transition from the second contact surface (22) to the third contact surface (23).
9. Control circuit according to one of the preceding claims, wherein the receiver (30) has a fastening section (33) and a spring section (34) by which the at least one first contact (31) and the at least one second contact (32) are formed, such that the at least one first contact (31) and the at least one second contact (32) can be pressed against the respective contact track (10, 20) in a spring-like manner.
10. Hand tool comprising an electrically operated actuator, an actuator control for controlling the actuator, a standby circuit and a control circuit (1) according to one of the preceding claims, wherein the standby circuit is electrically contacted with the first circuit output (41) and the actuator control is electrically contacted with the second circuit output (42) and / or the third circuit output (43). * * * * *
Citation Information
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