Impact screw-in / screw-out device with idling control

Abstract

The present invention relates to an impact screwing / unscrewing device, comprising: an electric motor having a rotor; means for controlling the motor, the means being capable of transmitting commands to the motor; and an impact mechanism, the impact mechanism comprising: at least one anvil mounted for rotation about the axis of rotation of the rotor; At least one hammer rotatable by the motor about the axis, the hammer comprising at least a disengaged position in which the hammer cannot collide with the at least one anvil when rotated by the motor; an engagement position in which the hammer can impact the at least one anvil when rotated by the motor; and at least one hammer capable of moving between one position and another. According to the invention, a variation of the command provided to the motor by the means for controlling triggers a movement of the at least one hammer from one position to another.

Description

Technical Field

[0001] 1. Field of the Invention The field of the present invention is the field of design and manufacture of impact screwing / unscrewing devices, more commonly known as impact wrenches.

Background Art

[0002] 2. Prior Art Impact wrenches are tools that have been conventionally used to tighten and loosen elements such as nuts and screws without causing torque feedback to the operator's hand using them.

[0003] Such tools comprise an electric or pneumatic motor and an impact mechanism, the input of which is connected to the rotor of the motor and the output of which comprises an output square that can rotate a screwing tool. The impact mechanism typically comprises a flywheel that can be rotated by the motor and more typically carries a mass body called a hammer, which can strike the output square, which acts as an anvil and thus rotates it to transmit torque to the element to be tightened-loosened. Thus, the impact mechanism converts the kinetic energy of a rotating mass body (driven by the motor) into impact energy. There are several types of impact mechanisms, but they all share the common feature of having one or more hammers that strike the output square.

[0004] There are different types of impact mechanisms such as twin hammers, two jaws, or pin clutch mechanisms, all of which share the common feature of systematically generating a determined number of impacts per revolution, generally equal to 1, sometimes 2. The number of impacts per revolution is related to the kinematics of the impact mechanism and cannot be changed.

[0005] All impact mechanisms operate on the same principle: a number of impacts are required to gradually reach the tightening torque. Therefore, the tightening torque of an impact wrench depends on the number and amount of energy transmitted to the anvil during each impact. Generally, the tightening torque of an impact wrench is claimed to correspond to the torque reached after 10 seconds of screwing.

[0006] To quickly achieve high tightening torque, the energy transferred to the output square during each impact must be high. This can be achieved by increasing the rotational speed of the impact mechanism before impact. This requires implementing a more powerful motor, which is a drawback, particularly in terms of overall dimensions, weight, and cost.

[0007] Another solution involves activating the hammer by idling the impact wrench, i.e., keeping the hammer in a disengaged position where it cannot collide with the anvil until the motor reaches a predetermined speed, and then positioning the hammer in an engaged position where it can collide with the anvil and generate a powerful impact.

[0008] While this technology is interesting, it requires the implementation of an actuator independent of the motor to move the hammer from either the engaged or disengaged position to the other. Therefore, this type of impact wrench is structurally complex.

[0009] Therefore, impact wrenches can be further improved to enable the rapid attainment of high tightening torque. [Overview of the Initiative]

[0010] 3. Purpose of the Invention The present invention aims to provide effective solutions to at least some of these various problems.

[0011] In particular, according to at least one embodiment, the present invention aims to provide an electric shock wrench that enables rapid attainment of high tightening torque.

[0012] According to at least one embodiment, the present invention particularly aims to provide such an impact wrench in a simple design.

[0013] According to at least one embodiment, the present invention further aims to provide such an impact wrench that is reliable and robust.

[0014] According to at least one embodiment, the present invention further aims to provide such a cost-effective impact wrench.

[0015] 4. Description of the Invention For this purpose, the present invention is an impact screw-in / screw-out device, An electric motor equipped with a rotor, Means for controlling the motor, including means capable of transmitting commands to the motor, Includes an impact mechanism, and the impact mechanism is At least one anvil mounted so as to rotate around the rotation axis of the rotor, At least one hammer that can be rotated by the motor around the rotation axis, and at least, When the hammer is rotated by the motor, there is a disengaged position in which it cannot collide with the at least one anvil, When the hammer is rotated by the motor, an engagement position is provided in which it can collide with the at least one anvil, We propose an apparatus comprising at least one hammer that can move between two points.

[0016] According to the present invention, a variation in the command supplied to the motor by the means for control triggers a movement of the at least one hammer from one position to the other.

[0017] Therefore, according to this aspect of the present invention, a simple variation in the command supplied to the motor allows the hammer to move from one of its positions to another, and there is no need to implement an actuator that enables this movement to occur. This makes the device according to the present invention very simple in design, but nevertheless, it allows for rapid attainment of high tightening torque by enabling the striking mechanism to be activated when the motor is operating fast enough.

[0018] According to one possible feature, the device comprises a flywheel coaxial with the rotor.

[0019] According to one possible feature, the means for controlling the motor enables the device to be mounted to perform a screwing or unscrewing operation, the operation involves performing a series of consecutive impact cycles in which the hammer strikes the anvil, and the means for control is capable of transmitting commands to the motor. The means for control is capable of generating a variation in the command instructions supplied to the motor by the means for control during each impact cycle, the variation of which triggers a movement of the at least one hammer from one of its positions to another.

[0020] According to one possible feature: The at least one hammer comprises at least one striking surface, and the at least one anvil comprises at least one impact surface. When the at least one hammer is in the engagement position and the at least one hammer is rotated by the motor, the striking surface and the impact surface can strike each other. When at least one of the hammers is in the disengaged position and is rotated by the motor, the striking surface and the collision surface cannot strike each other.

[0021] According to one possible feature: The rotor is provided with a drive shaft. The flywheel is coaxial with the drive shaft. The at least one hammer is attached to the flywheel so as to be movable between its disengaged position and its engaged position. The flywheel and the drive shaft are rotatably connected such that the flywheel is rotatable relative to the drive shaft over an angular range defined by at least one end position such that the at least one hammer is in its disengaged position. The device has the at least one hammer in its disengaged position when the drive shaft is in the at least one end position, and in its engaged position when the drive shaft is in a predetermined position within the angular range. In order to position the at least one hammer, it includes at least one actuating element acting on the at least one hammer.

[0022] According to one possible feature, the angular range is defined by two end positions of the drive shaft relative to the flywheel such that the flywheel and the drive shaft are rotatably connected and the at least one hammer is in its disengaged position.

[0023] According to one possible feature, the at least one hammer can rotate between its engaged position and its disengaged position along an axis parallel to the rotation axis of the motor.

[0024] According to one possible feature, it comprises an indexing pin fixed to the drive shaft so as to rotate with the drive shaft, and the indexing pin can abut against at least one stop fixed to the flywheel so as to rotate with the flywheel at the at least one end position so as to rotatably connect the drive shaft and the flywheel.

[0025] According to one possible feature: The at least one actuating element comprises at least one fin fixed to the drive shaft so as to rotate with the drive shaft, and the at least one fin can move along at least one ramp firmly connected to the at least one hammer. The at least one fin and the at least one ramp are configured to arrange the at least one hammer in the non-engagement position when the drive shaft is in the at least one end position, and configured to arrange the at least one hammer in the engagement position when the drive shaft is in the predetermined position within the angular range, are shaped.

[0026] According to one possible feature: The device comprises at least one driven gear fixed to each of the hammers so as to rotate with the hammers, and the hammers are firmly connected to the flywheel. The at least one actuating element comprises a drive gear fixed to the drive shaft so as to rotate with the drive shaft and engaged with one or more of the driven gears. The relative movement of the drive shaft with respect to the flywheel enables the at least one hammer to be moved between its engagement position and its non-engagement position.

[0027] According to one possible feature, the at least one hammer can translate between its engagement position and its non-engagement position along an axis parallel to the axis of rotation of the drive shaft.

[0028] According to one possible feature, the system includes a secondary drive shaft that is fixed to the drive shaft and rotates with the drive shaft, but is freely translatable, The secondary drive shaft is mounted so as to be able to translate and rotate relative to the flywheel along the rotation axis of the drive shaft. The secondary drive shaft comprises at least one cam such that at least one guide pin, which is firmly connected to the flywheel, can move relative to the cam. The at least one cam is, To enable the secondary drive shaft to rotate relative to the flywheel over the angular range between the at least one end position and the predetermined position, To enable translational movement of the secondary drive shaft relative to the flywheel during the movement of the flywheel between the at least one end position and the predetermined position, It has a molded profile.

[0029] According to one possible feature, the at least one hammer is It is fixed to the drive shaft so as to move in translation with the drive shaft, but it is not fixed so as to rotate with it. The drive shaft is mounted so as to be able to translate relative to the flywheel so as to move between an engaged position and an unengaged position.

[0030] According to one possible feature, the motor includes an internal stator with coils, The rotor is external, The at least one hammer is fixed to the rotor so as to rotate with the rotor, and the at least one hammer is mounted so as to be able to rotate relative to the rotor between an engaged position and an unengaged position along an axis parallel to the rotor's axis of rotation. The magnetic field produced by the aforementioned coil is When the means for control supplies power to the coil to rotate the rotor, the at least one hammer is positioned in its disengaged position. When the means for control does not supply power to the coil to rotate the rotor, the means for control acts on the at least one hammer to position the at least one hammer in its engagement position.

[0031] According to one possible feature, the means for control is, The motor is accelerated in one direction, the drive shaft is positioned at one end of its terminal position, and a command is supplied to rotate the flywheel in one direction to a predetermined speed. A deceleration command is supplied to the motor such that the drive shaft moves relative to the flywheel over the angular range to reach the predetermined position, positioning the at least one hammer in its engagement position and causing the at least one hammer to collide with the at least one anvil. To supply a command to re-accelerate the motor in the aforementioned direction, It is possible.

[0032] According to one possible feature, the means for control is, A command is issued to the motor to rotate the rotor and to place the at least one hammer in the disengaged position, The system is configured to supply a command to the motor that does not supply power in order to position the at least one hammer in the disengaged position and rotate the rotor in the direction so that the at least one hammer collides with the at least one anvil.

[0033] According to one possible feature, the means for control is configured to maintain the rotation of the rotor at the predetermined speed until the means for control of at least one parameter indicating that the at least one hammer is in a predetermined angular position relative to the at least one anvil along the rotation axis of the rotor is detected.

[0034] According to one possible feature, the motor is equipped with a sensor for measuring the angular position of the rotor, The means for control is, Based on measurements taken using the aforementioned sensor, the angular position of the at least one anvil at the end of each impact cycle is determined and recorded. From there, the system is configured to estimate the angular position of the at least one hammer relative to the at least one anvil and the arrival of the predetermined angular position during subsequent impact cycles.

[0035] According to one possible feature, the system comprises an output shaft firmly connected to at least one anvil, The apparatus includes a sensor for measuring the angular position of the output shaft, The means for control is, At the end of each impact cycle, the angular position of the output shaft is determined and recorded. From there, the system is configured to estimate the angular position of the at least one hammer relative to the at least one anvil and the arrival of the predetermined angular position during subsequent impact cycles.

[0036] According to one possible feature, the means for control can control the motor to stabilize the angular misalignment between the rotor and the flywheel at the predetermined angular position of the at least one hammer.

[0037] According to one possible feature, the flywheel is equipped with an angle sensor capable of measuring the angular position of the flywheel, The means for control can calculate the angular position of the rotor relative to the flywheel.

[0038] 5. Description of the drawings Further features and advantages of the present invention will become apparent by reading the following description and accompanying drawings of specific embodiments, which are given merely as non-limiting examples for illustrative purposes. [Brief explanation of the drawing]

[0039] [Figure 1] A longitudinal cross-sectional view of the apparatus according to the first embodiment of the present invention is shown. [Figure 2] Figure 1 shows a disassembled view of the device. [Figure 3] Figure 1 shows a different cross-section of the apparatus with the hammer in the disengaged position. [Figure 4] Figure 1 shows a different cross-section of the device with the hammer in the engagement position. [Figure 5] Figure 1 shows a different cross-section of the device with the hammer in the engagement position. [Figure 6] This shows the relative positions of the hammer and anvil, which do not allow the hammer to move to the engagement position. [Figure 7] (a) shows the relative positions of the hammer and anvil that allow the hammer to move to the engagement position. (b) shows the relative positions of the hammer and anvil when the hammer is in the engagement position. [Figure 8] This shows the different relative positions of the hammer and anvil in the operating device. [Figure 9] A longitudinal cross-sectional view of the apparatus according to a second embodiment of the present invention is shown. [Figure 10] Figure 9 shows a disassembled view of the device. [Figure 11] Figure 9 shows different cross-sections of the apparatus, where the hammer is in the engagement position and collides with the anvil. [Figure 12] Figure 9 shows a different cross-section of the apparatus with the hammer in the disengaged position. [Figure 13]Figure 9 shows a different cross-section of the apparatus where the hammer is in the engaged position and does not collide with the anvil. [Figure 14] A longitudinal cross-sectional view of the apparatus according to the third embodiment of the present invention is shown. [Figure 15] Figure 14 shows partial perspective views of the striking mechanism of the device at different locations. [Figure 16] Figure 14 shows a disassembled view of the device. [Figure 17] (b) shows a guide pin that contacts the stopper to position the hammer in the disengaged position, and (a) shows the normal relative position of the hammer and the anvil in the disengaged position. [Figure 18] Figure 14 shows a cross-sectional view of the apparatus. [Figure 19] (b) shows a guide pin that does not contact the stopper to position the hammer in the engagement position, and (a) shows the hammer in the engagement position that collides with the anvil. [Figure 20] (a) shows a guide pin that contacts the stopper to position the hammer in the disengaged position, and (a) shows the normal relative position of the hammer and the anvil in the disengaged position. [Figure 21] A fourth embodiment of the apparatus according to the present invention is shown. [Figure 22] This shows the time-dependent changes in the motor speed and acceleration of the device according to the present invention while it is in operation. [Modes for carrying out the invention]

[0040] 6. Description of Specific Embodiments 6.1. First Embodiment Referring to Figures 1-8, a first embodiment of the screw-in / screw-out device according to the present invention, also known as an impact wrench, is shown.

[0041] Such a device comprises a casing 1 that houses an electric motor 2 having a stator 20 and a rotor (rotating body, rotor) 21. It also includes an actuation trigger 10.

[0042] The rotor 21 is provided with a drive shaft 3, and two fins 4 protrude from its end, extending away from each other along an axis perpendicular to the longitudinal axis of the drive shaft 3.

[0043] The end of the drive shaft 3 is further equipped with an indexing pin 5.

[0044] The device includes an impact mechanism 6, which includes the following: At least one anvil 60 mounted so as to rotate around the axis of rotation of the rotor 21; At least one hammer 61 that is rotatable by a motor along the aforementioned axis.

[0045] Each anvil 60 has two opposing impact surfaces 601.

[0046] Anvil 60 is rotatably connected to an output shaft 602, also called an output square, which can carry a screw-in / screw-out bit for rotating an element to be screwed in / unscrewed, such as a nut or screw.

[0047] Each hammer 61 comprises two opposing striking surfaces 610. Each hammer 61 further comprises two lugs 620 separated by a central recess 630 that defines a ramp (inclined) profile 640 on which the fins 4 of the drive shaft can move.

[0048] The hammer 61 is firmly connected to the flywheel 7. The flywheel 7 forms a bell in which the hammer 61 is positioned. The hammer 61 is mounted so as to be able to rotate on a shaft 70 fixed to the flywheel 7, which is stationary and extends along an axis parallel to the rotor's axis of rotation.

[0049] The rotor, drive shaft, flywheel, and output shaft are coaxial.

[0050] The hole 71 moves around the center of the flywheel, and a groove 72 with a larger outer diameter is formed around it, extending over an angular portion defined by two stoppers 73. The implementation of two stoppers allows the device to operate both in screwing in and unscrewing. The implementation of a single stopper allows the device to operate in only one or the other of these two directions.

[0051] The indexing pin 5 has a shape that complements the shape of the groove 72 and can move within it until it contacts one of the stoppers 73 that define the groove 72. Thus, the flywheel 7 can rotate along its axis on the drive shaft 3 over an angular range defined by the two stoppers 73.

[0052] Therefore, the flywheel is rotatable relative to the drive shaft over an angular range defined by at least one end position, which in this embodiment is two end positions defined by the stop 73, and the flywheel and drive shaft are rotatably connected. When the indexing pin 5 is in contact with the stop 73, the flywheel 7 and drive shaft 3 are rotatably connected in a direction that brings the indexing pin closer to the stop.

[0053] Each hammer 61 can rotate around the corresponding shaft 70 within at least the following ranges: A disengaged position in which the hammer cannot collide with the anvil 60 when it is rotated by the motor. An engagement position in which the hammer can collide with the anvil 60 when it is rotated by the motor.

[0054] The striking surface and the impact surface can strike each other when at least one hammer is in its engagement position and at least one hammer is rotated by the motor.

[0055] The striking surface and the impact surface cannot strike each other when at least one hammer is in a disengaged position and at least one hammer is being rotated by the motor.

[0056] The aforementioned device is When the drive shaft is in the at least one end position, it is in its disengaged position. When the drive shaft is in a predetermined position within the angular range, it is in its engagement position. To position the at least one hammer, the system includes at least one actuating element that acts on the at least one hammer.

[0057] The actuating element is fixed to the drive shaft 3 to rotate with it and includes fins 4 that can move relative to the ramp (inclined portion) 640 of the lug 620 of the hammer 61.

[0058] Fins 4 and ramp 640 are When the drive shaft is in the at least one end position, the at least one hammer is positioned in the disengaged position, and The drive shaft is configured to be positioned in the engagement position when it is in the predetermined position within the angular range. It is molded.

[0059] When the indexing pin 5 contacts one of the stopper sections 73, the fin 4 is housed in the central recess 630 of the hammer 61. Thus, the hammer is held in its disengaged position, and the flywheel is rotatably connected to the drive shaft so that the motor can freely drive the hammer around the anvil without colliding with it.

[0060] As the indexing pin 5 moves within the groove between the two stoppers 73, it takes a predetermined position such that the fin 4 interacts with the lug 620 to put the hammer into an engaged position, and thus its striking surface collides with the impact surface of the anvil.

[0061] Figure 3(c) shows the indexing pin 5 in contact with the flywheel stop 73. Figure 3(b) shows the corresponding disengaged position of the hammer. Figure 3(a) shows the normal angular position of the hammer as it rotates around the anvil in the disengaged position.

[0062] Figure 4(c) shows the indexing pin 5 in a predetermined position between the stoppers 73 corresponding to the hammer's engagement position. Figure 4(b) shows the corresponding engagement position of the hammer. Figure 4(a) shows the normal angular position of the hammer relative to the anvil before impact at the hammer's engagement position.

[0063] Figure 5(c) shows the indexing pin 5 at a predetermined position between the stoppers 73 corresponding to the hammer's engagement position. Figure 5(b) shows the corresponding engagement position of the hammer. Figure 5(a) shows the position of the hammer at the engagement position where it strikes the anvil.

[0064] The device is equipped with means for controlling the motor, and these means can transmit commands to the motor.

[0065] These control mechanisms include a user interface such as a screen and / or keyboard, allowing the user to input, for example, a set value for the tightening torque or a percentage of the maximum tightening torque.

[0066] The means for control include a controller for translating user commands into speed according to pre-set control laws. They enable the implementation of a method for controlling the apparatus to work toward performing a screwing or unscrewing operation, which involves performing a series of continuous impact cycles in which each hammer strikes an anvil.

[0067] The motor's angle sensor allows the controller to know the rotor's position in real time and calculate its speed.

[0068] When the operator activates the trigger on the impact wrench to trigger a screwing or unscrewing operation, the control means transmits a command to the motor to reach a predetermined rotational frequency Vi. The device is in a normal state, for example, as shown in Figure 8(a).

[0069] The drive shaft moves within the groove of the flywheel until it contacts the stop section 73 (Figures 8(a) to 8(b) to 8(c)). Thus, the flywheel is rotatably connected to the drive shaft, the hammer is positioned in its disengaged position by the fins, and the anvil remains rotatably stationary (see Figure 8(d)).

[0070] When the rotor reaches a rotational frequency Vi, the control means controls the motor so that it remains at rotational frequency Vi until the condition is satisfied that the impact mechanism is in the appropriate position prior to impact is satisfied. From Figures 6 and 7, it is clear that when the hammers are in the disengaged position, they form a bell around the anvil. Thus, they can rotate around the anvil without interfering with it. However, in order to move from the disengaged position to the engaged position, the hammers must be in a specific position relative to the anvil. More specifically, the relative position of the hammers and the anvil must be such that the hammers can move to their engaged position without friction with the outer surface of the anvil. In Figure 6, the relative position of the hammers with respect to the anvil does not allow the hammers to move from the disengaged position to their engaged position. Conversely, in Figure 7, the relative position of the hammers with respect to the anvil allows the hammers to move from their disengaged position (see Figure 7(a)) to their engaged position (see Figure 7(b)).

[0071] To achieve this, according to the first alternative embodiment, an angular position sensor can be placed on the output shaft to which the anvil is firmly connected.

[0072] At the end of each impact, this sensor measures the angular position of the output shaft, and therefore the angular position of the anvil, which remains unchanged until the subsequent impact. Thus, during the subsequent impact cycle, the position of the anvil is known (corresponding to that measured at the end of the previous impact cycle), while the position of the hammer is estimated from the rotor position measured by the motor's angle sensor. Thus, the relative position of the hammer to the anvil can be known, and the motor's deceleration can be controlled so that the hammer is positioned in its engaged position only when the angular position of the hammer relative to the anvil allows the hammer to move from its unengaged position to its engaged position without interfering with the anvil.

[0073] According to the second alternative configuration, the angular position of the anvil can be determined without mounting an angle sensor on the output shaft. In such a case, the angular position of the anvil is determined using the motor's angle sensor at each impact. More specifically, when a sharp decrease in the motor's rotational frequency is detected, following the occurrence of an impact in the impact mechanism, a means for control records the rotor position corresponding to the anvil position. Thus, in subsequent impact cycles, the relative position of the anvil recorded during the previous cycle and the relative position of the hammer, which corresponds to that measured in real time by the motor's angle sensor, can be known. Thus, the relative position of the hammer with respect to the anvil can be known, and the motor's deceleration can be controlled so that the hammer is positioned in its engaged position only when the angular position of the hammer with respect to the anvil allows the hammer to move from its disengaged position to its engaged position, without being hindered by the potential positioning of the hammer facing the anvil.

[0074] According to this alternative configuration, at least one impact must occur before the initial position of the anvil can be estimated. Therefore, the screw-in cycle begins with a first impact at low speed, and for this reason, the electric braking command is initiated as soon as the desired speed is reached, without any other conditions.

[0075] When the relative position of the hammer with respect to the anvil allows the hammer to move from a disengaged position to its engaged position, the motor can be controlled to position the hammer in that engaged position.

[0076] For the hammer to be in its engaged position, the angular offset between the drive shaft and the flywheel must be equal to a predetermined value α.

[0077] When the relative position of the hammer with respect to the anvil is appropriate, the motor is decelerated by means of control such that the angular misalignment between the flywheel and the drive shaft reaches a predetermined value α such that the hammer is in its engaged position.

[0078] Immediately before the engine is decelerated, the drive shaft and flywheel rotate at a velocity Vi. Once the engine is decelerated, the flywheel continues to rotate at velocity Vi due to its inertia. Therefore, its angular position can be determined from its velocity and the position occupied immediately before the motor is braked, which is the rotor position measured by the motor's angle sensor when the motor is decelerated. Alternatively, the angular position of the flywheel can be determined by using an angle sensor placed on the flywheel. The position of the drive shaft, corresponding to the rotor position, can also be determined in real time. By considering this data, it is possible to detect the time at which the offset between the flywheel and the drive shaft reaches a predetermined value α such that the hammer is in its engaged position (see Figure 8(e)).

[0079] When this time is detected, the control means re-accelerates the motor to speed Vi so that the angular misalignment between the drive shaft and the flywheel is maintained at a predetermined value α such that the hammer is in the engaged position.

[0080] Speed ​​Vi is maintained until the means for control detect a sharp decrease in the motor speed following the point in time when the hammer strikes the anvil and rotates the output shaft, and thus the element to be screwed in.

[0081] The position of the output shaft is measured at the end of the impact cycle, and then a new impact cycle is performed. The impact cycle is repeated continuously until the desired tightening torque is reached.

[0082] Figure 22 shows the changes in motor speed and acceleration over time during the shock cycle.

[0083] The screw-in operation typically involves two consecutive steps: The approach phase is when the screw is not in contact with the element being fastened. The screw typically has to travel a long distance, and during that time, it exerts little resistance before reaching the element to be fastened. Therefore, the rotational speed of the screw must be relatively high. The tightening phase is when the screw is in contact with the element being fastened. The torque required to rotate the screw increases significantly.

[0084] The approach phase is carried out by generating a large number of small impacts.

[0085] 6.2. Second Embodiment A second embodiment of the impact wrench according to the present invention is shown with reference to Figures 9 to 13.

[0086] The following will only describe the differences between the first and second embodiments.

[0087] In this second embodiment, the device comprises at least one driven gear 8 fixed to each of the hammers 61 and rotating with it.

[0088] In this case, the actuation element is fixed to the drive shaft 3 and rotates with it, and comprises a drive gear 9 that engages with the driven gear of each hammer 61.

[0089] The relative motion of the drive shaft 3 with respect to the flywheel 7 allows at least one hammer to move between its engaged and disengaged positions.

[0090] Figure 12(c) shows the indexing pin 5 in contact with the flywheel stop 73. Figure 12(a) shows the corresponding disengaged position of the hammer. Figure 12(b) shows the meshing of the gears.

[0091] Figure 13(c) shows the indexing pin 5 at a predetermined position between the stoppers 73 corresponding to the hammer's engagement position. Figure 13(a) shows the corresponding engagement position of the hammer and the hammer's normal position relative to the anvil before impact. Figure 13(b) shows the meshing of the gears.

[0092] Figure 11(c) shows the indexing pin 5 at a predetermined position between the stoppers 73 corresponding to the hammer's engagement position. Figure 11(a) shows the corresponding engagement position of the hammer and the position of the hammer when it collides with the anvil. Figure 11(b) shows the meshing of the gears.

[0093] The means for control and the means for controlling the motor are the same as in the first embodiment.

[0094] 6.3. Third Embodiment Referring to Figures 14 to 20, a third embodiment of the impact wrench according to the present invention is shown. Only the main differences between the third embodiment and the previous two embodiments are described below.

[0095] In this third embodiment, the at least one hammer can be translated along an axis parallel to the axis of rotation of the drive shaft between an engaged position and an unengaged position.

[0096] In this embodiment, the device includes a secondary drive shaft 9 that is fixed to the drive shaft 3 of the rotor 21 and rotates with it, but is freely translatable.

[0097] The secondary drive shaft 9 is mounted so as to be able to translate and rotate relative to the flywheel 7 along the axis of rotation of the drive shaft 3.

[0098] The secondary drive shaft 9 includes at least one cam 90 on which at least one guide pin 91, which extends perpendicular to the rotation axis of the flywheel and is firmly connected to the flywheel 7, can move.

[0099] The cam 9 is defined by two stop sections 73 that define the angular range in which the flywheel rotates freely relative to the secondary drive shaft between two end positions.

[0100] At least one cam 90 has a profile that allows the secondary drive shaft 9 to rotate relative to the flywheel over the angular range between an end position and a predetermined position within the angular range, and that allows translational motion of the secondary drive shaft relative to the flywheel during movement from either the end position or the predetermined position.

[0101] The hammer 61 is a shaft mounted to be able to translate inside the flywheel's guide ramp 700 along an axis parallel to the flywheel's axis of rotation. Each hammer has a groove 650 inside which the edge of a washer 100 fixed to the end of the secondary drive shaft 9 is housed, linking the hammer translationally to the secondary drive shaft and moving the hammer between its engaged and disengaged positions.

[0102] Elastic return means such as compression spring 11 act on the hammer to bias it and return it to the disengaged position.

[0103] Figures 15(a) and 15(b) show the hammer in the disengaged position. Figure 15(c) shows the hammer in the engaged position.

[0104] Figure 17(b) shows the guide pin 91 that contacts the stop 73 to position the hammer in the disengaged position. Figure 17(a) shows the normal relative position of the hammer in the disengaged position with respect to the anvil.

[0105] Figure 20(a) shows the guide pin 91 that contacts the stop 73 to position the hammer in the disengaged position. Figure 20(a) shows the normal relative position of the hammer in the disengaged position with respect to the anvil.

[0106] Figure 19(b) shows the guide pin 91 that does not contact the stopper 73 in order to position the hammer in the engagement position. Figure 19(a) shows the hammer in the engagement position in which it collides with the anvil.

[0107] The means for control and the means for controlling the motor are the same as in the first embodiment.

[0108] 6.4. Fourth Embodiment A fourth embodiment is shown with reference to Figure 21.

[0109] In this embodiment, the motor includes an internal stator 20 with coils 200, and the rotor 21 is external.

[0110] The external rotor forms the flywheel.

[0111] The hammer is fixed to the rotor so as to rotate with it, and is also mounted so as to rotate relative to the rotor along an axis parallel to the axis of rotation between an engaged position and an unengaged position.

[0112] The striking surface 610 of the hammer 61 protrudes from the outer circumference of the rotor and strikes the anvil in its engagement position.

[0113] In its disengaged position, the striking surface 610 of the hammer 61 does not protrude from the periphery of the rotor so as not to collide with the anvil.

[0114] In this embodiment, the magnetic field created by the coil is: When a means for controlling the rotor supplies power to the coil, the hammer is positioned in the disengaged position. To rotate the rotor, when the control means does not supply power to the coil, the hammer is positioned in its engagement position. It acts on the hammer in this way.

[0115] Therefore, the means for control is the motor: The hammer is positioned in its disengaged position, and a rotation command is given to rotate the rotor, A motor stop command is issued to position the hammer in its engagement position and trigger the hammer's impact against the anvil, It can transmit information.

[0116] Elastic return mechanisms, such as compression springs, and / or centrifugal force, allow the hammer to move to its engagement position when the power supply to the coil is cut off.

[0117] In Figure 21(a), the hammer is in the disengaged position. In Figure 21(b), the hammer is in the engaged position.

Claims

1. An impact screw-in / screw-out device, An electric motor equipped with a rotor, Means for controlling the motor, including means capable of transmitting commands to the motor, Includes an impact mechanism, and the impact mechanism is At least one anvil mounted so as to rotate around the rotation axis of the rotor, At least one hammer that can be rotated by the motor around the rotation axis, and at least, When the hammer is rotated by the motor, there is a disengaged position in which it cannot collide with the at least one anvil, When the hammer is rotated by the motor, an engagement position is provided in which it can collide with the at least one anvil, Includes at least one hammer that can move between, A device characterized in that fluctuations in the command instructions supplied to the motor by the means for control trigger movement of at least one hammer from one position to the other position.

2. The apparatus according to claim 1, characterized in that it comprises a flywheel coaxial with the rotor.

3. The means for controlling the motor enables the device to be mounted to perform a screwing or unscrewing operation, the operation including performing a series of consecutive impact cycles in which the hammer strikes the anvil, and the means for controlling the operation It is possible to transmit commands to the motor, The apparatus according to claim 1 or 2, wherein the means for control is capable of generating a variation in the command instructions supplied to the motor by the means for control during each impact cycle, the variation triggering a movement of the at least one hammer from one of its positions to another.

4. The at least one hammer comprises at least one striking surface, and the at least one anvil comprises at least one impact surface. When the at least one hammer is in the engagement position and the at least one hammer is rotated by the motor, the striking surface and the impact surface can strike each other. When the at least one hammer is in the disengaged position and the at least one hammer is rotated by the motor, the striking surface and the impact surface cannot strike each other. The apparatus according to any one of claims 1 to 3, characterized in that

5. The rotor is provided with a drive shaft. The flywheel is coaxial with the drive shaft, The at least one hammer is mounted on the flywheel so as to be able to move between an unengaged position and an engaged position. The flywheel and the drive shaft are rotatably connected, and the flywheel is rotatable relative to the drive shaft over an angular range defined by at least one end position such that the at least one hammer is in its disengaged position. The aforementioned device is When the drive shaft is in the at least one end position, it is in its disengaged position. When the drive shaft is in a predetermined position within the angular range, it is in its engagement position. The apparatus according to claim 2, either alone or in combination with claim 3 or 4, comprising at least one actuating element acting on the at least one hammer in order to position the at least one hammer.

6. The apparatus according to claim 5, characterized in that the angular range is defined by the positions of the two ends of the drive shaft relative to the flywheel such that the flywheel and the drive shaft are rotatably connected and at least one hammer is in its disengaged position.

7. The apparatus according to any one of claims 1 to 6, characterized in that the at least one hammer can rotate between the engaged position and the disengaged position of the at least one hammer along an axis parallel to the rotation axis of the motor.

8. The apparatus according to claim 5 or 6, comprising an indexing pin fixed to the drive shaft so as to rotate together with the drive shaft, wherein the indexing pin can contact at least one stop portion fixed to the flywheel so as to rotate together with the flywheel at at least one end position, so as to rotatably connect the drive shaft and the flywheel.

9. The at least one actuation element comprises at least one fin fixed to the drive shaft so as to rotate together with the drive shaft, and the at least one fin is capable of moving along at least one ramp firmly connected to the at least one hammer. The at least one fin and the at least one ramp are When the drive shaft is in the at least one end position, the at least one hammer is positioned in the disengaged position, and The drive shaft is configured to be positioned in the engagement position when it is in the predetermined position within the angular range. The apparatus according to claim 8, characterized by being molded.

10. The apparatus comprises at least one driven gear fixed to each of the hammers so as to rotate together with the hammers, and the hammers are firmly connected to the flywheel. The at least one actuation element comprises a drive gear fixed to the drive shaft so as to rotate together with the drive shaft and engaged with one or more of the driven gears, The apparatus according to claim 8, characterized in that the relative motion of the drive shaft with respect to the flywheel allows the at least one hammer to move between its engaged position and its disengaged position.

11. The apparatus according to any one of claims 1 to 6, characterized in that the at least one hammer can be translated between an engaged position and an unengaged position along an axis parallel to the rotation axis of the motor.

12. The drive shaft is fixed to the aforementioned drive shaft and rotates together with the drive shaft, but is equipped with a secondary drive shaft that can translate freely, The secondary drive shaft is mounted so as to be able to translate and rotate relative to the flywheel along the rotation axis of the drive shaft. The secondary drive shaft comprises at least one cam such that at least one guide pin, which is firmly connected to the flywheel, can move relative to the cam. The at least one cam is, To enable the secondary drive shaft to rotate relative to the flywheel over the angular range between the at least one end position and the predetermined position, To enable translational movement of the secondary drive shaft relative to the flywheel during the movement of the flywheel between the at least one end position and the predetermined position, The apparatus according to claim 5, characterized by having a molded profile.

13. The at least one of the hammers is It is fixed to the drive shaft so as to move in translation with the drive shaft, but it is not fixed so as to rotate with it. The apparatus according to claim 12, characterized in that it is mounted such that it can be translated relative to the flywheel so as to move between an engaged position and an unengaged position by the drive shaft.

14. The motor includes an internal stator equipped with coils, The rotor is external and forms the flywheel, The at least one hammer is fixed to the rotor so as to rotate with the rotor, and the at least one hammer is mounted so as to be able to rotate relative to the rotor between an engaged position and an unengaged position along an axis parallel to the rotor's axis of rotation. The magnetic field produced by the aforementioned coil is When the means for control supplies power to the coil to rotate the rotor, the at least one hammer is positioned in its disengaged position. When the means for control does not supply power to the coil to rotate the rotor, the at least one hammer is positioned in its engagement position. The apparatus according to claim 2, which acts on at least one of the hammers, either alone or in combination with claim 3 or 4.

15. The means for control is, The motor is accelerated in one direction, the drive shaft is positioned at one end of its terminal position, and a command is supplied to rotate the flywheel in one direction to a predetermined speed. A deceleration command is supplied to the motor such that the drive shaft moves relative to the flywheel over the angular range to reach the predetermined position, positioning the at least one hammer in its engagement position and causing the at least one hammer to collide with the at least one anvil. To supply a command to re-accelerate the motor in the aforementioned direction, The apparatus according to claim 5, which is characterized by being able to do so, either alone or in combination with any one of claims 6 to 13.

16. The means for control is, A command is issued to the motor to rotate the rotor and to position the at least one hammer in the disengaged position, The apparatus according to claim 14, characterized in that it is configured to supply a command to the motor not to supply power in order to rotate the rotor by positioning the at least one hammer in the engagement position and causing the at least one hammer to collide with the at least one anvil.

17. The apparatus according to claim 15, wherein the means for control is configured to maintain the rotation of the rotor at a predetermined speed until the means for controlling at least one parameter indicating that the at least one hammer is at a predetermined angular position along the rotation axis of the rotor with respect to the at least one anvil is detected.

18. The apparatus according to claim 16, wherein the means for control is configured to maintain the rotation of the rotor at a predetermined speed until the means for controlling at least one parameter indicating that the at least one hammer is at a predetermined angular position relative to the at least one anvil along the rotation axis of the rotor is detected.

19. The motor is equipped with a sensor for measuring the angular position of the rotor, The means for control is, Based on measurements taken using the aforementioned sensor, the angular position of the at least one anvil at the end of each impact cycle is determined and recorded. The apparatus according to claim 17 or 18, characterized in that it is configured to estimate the angular position of the at least one hammer with respect to the at least one anvil and the arrival of the predetermined angular position in a subsequent impact cycle.

20. The output shaft is firmly connected to at least one of the anvils, The apparatus includes a sensor for measuring the angular position of the output shaft, The means for control is, At the end of each impact cycle, the angular position of the output shaft is determined and recorded. The apparatus according to claim 17 or 18, characterized in that it is configured to estimate the angular position of the at least one hammer with respect to the at least one anvil and the arrival of the predetermined angular position in a subsequent impact cycle.

21. The apparatus according to any one of claims 17 to 20, characterized in that the means for control can control the motor to stabilize the angular misalignment between the rotor and the flywheel at the predetermined angular position of the at least one hammer.

22. The flywheel is equipped with an angle sensor capable of measuring the angular position of the flywheel, The apparatus according to claim 21, characterized in that the means for control can calculate the angular position of the rotor relative to the flywheel.

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