Patent Description:
An open end power tool may comprise a driven member rotatable about a driven axis and having a driven member opening for receiving a nut, or a shaft around which the nut is threaded, therethrough in a radial direction with respect to the driven axis. In order to position the driven member in an open position where the nut or the shaft can be radially received through the driven member opening, the power tool may comprise a mechanical stop, such as a protrusion. By driving the driven member in a first direction, the nut can be tightened. By driving the driven member in a second direction, opposite to the first direction, the driven member can be driven against the mechanical stop to ensure that the driven member is positioned in the open position. Such power tools have a disadvantage in that the driven member can only be used to rotate the nut in one direction. Such power tools are for example known from <CIT> and <CIT>.

In order to overcome the above disadvantage, some open end power tools comprise a sensor for detecting when the driven member is positioned in the open position. Such power tools do not need the mechanical stop and the driven member can therefore be driven to rotate the nut in both directions. However, such sensor adds costs and complexity to the power tool. For example, the sensor needs associated cabling.

<CIT> discloses an electrical wrench, which allows for rotating an opening gear in a first and a second direction, wherein the neutral position is assumed by the use of a sensor, a control circuit and the motor of said wrench. <CIT> discloses an automatic bidirectional ratchet tightening mechanism, which corresponds to the preamble of independent claim <NUM>.

One object of the present disclosure is to provide an arrangement for a power tool, which arrangement enables dual direction rotation of a drive member and positioning of the drive member in a neutral position.

A further object of the present disclosure is to provide an arrangement for a power tool, which arrangement has a less complicated design.

A still further object of the present disclosure is to provide an arrangement for a power tool, which arrangement has a cost-efficient design.

A still further object of the present disclosure is to provide an arrangement for a power tool, which arrangement has an improved performance.

A still further object of the present disclosure is to provide an arrangement for a power tool, which arrangement reduces storage requirements.

A still further object of the present disclosure is to provide an arrangement for a power tool, which arrangement solves several or all of the foregoing objects in combination.

A still further object of the present disclosure is to provide a tool head for a power tool, which tool head solves one, several or all of the foregoing objects.

A still further object of the present disclosure is to provide a power tool comprising a tool head, which power tool solves one, several or all of the foregoing objects.

A still further object of the present disclosure is to provide a method of controlling an arrangement for a power tool, which method solves one, several or all of the foregoing objects.

According to a first aspect, there is provided an arrangement for a power tool, the arrangement comprising a base structure; a drive member rotatable relative to the base structure in a first direction and in a second direction from a neutral position; a stopping device comprising a movable element and a limiting element; wherein the stopping device is arranged to adopt a first state where the movable element is in a first region with respect to the limiting element, and where the stopping device allows rotation of the drive member in the first direction and generates a first counter torque against rotation of the drive member in the second direction from the neutral position; wherein the stopping device is arranged to adopt a second state where the movable element is in a second region with respect to the limiting element, and where the stopping device allows rotation of the drive member in the second direction and provides a second counter torque against rotation of the drive member in the first direction from the neutral position; and wherein the stopping device is deflectable to switch from the first state to the second state by rotating the drive member in the second direction from the neutral position with a second switching torque overcoming the first counter torque.

When the stopping device deflects to switch from the first state to the second state, the movable element flips between the first and second regions, e.g. from a first side to a second side of the limiting element. The stopping device provides a second torque peak that the second switching torque needs to overcome in order to switch the stopping device from the first state to the second state. The stopping device may further be deflectable to switch from the second state back to the first state by rotating the drive member in the first direction from the neutral position with a first switching torque overcoming the second counter torque. The stopping device thereby provides a first torque peak that the first switching torque needs to overcome in order to switch the stopping device from the second state back to the first state. An absolute value of the first switching torque may or may not be equal to an absolute value of the second switching torque.

The first counter torque may be generated by the limiting element limiting movement of the moveable element from the first region to the second region.

The second counter torque may be generated by the limiting element limiting movement of the moveable element from the second region to the first region.

In other words, the limiting element may be arranged to restrict the movement of the movable element from the first region to the second region and vice versa. The limiting element and the movable element may further be arranged such that the restriction may be overcome when the second switching torque overcoming the first counter torque (or a first switching torque overcoming the second counter torque) is applied to the drive member, whereby the movable element is forced to pass from the first region to the second region (or vice versa). This can be accomplished in several different ways, as will be described later on in the present specification.

Throughout the present disclosure, the power tool may be an open end power tool. Such power tool may comprise a driven axis; a base element having a base opening; a driven member having a driven member opening, the driven member being rotatable about the driven axis from an open position where the driven member opening is aligned with the base opening; and a drive transmission arranged to transmit a rotation of the drive member to a rotation of the driven member. When the drive transmission is configured such that the neutral position of the drive member corresponds to the open position of the driven member, the arrangement enables accurate positioning of the driven member in the open position without using sensors and dual directional rotation of the driven member over several full turns.

When the stopping device adopts the first state, the drive member can be rotated continuously with a plurality of full rotations in the first direction, e.g. for driving the driven member to rotate a nut in a clockwise direction. By rotating the drive member in the second direction with a second drive torque when the stopping device adopts the first state, the drive member will eventually be stopped by the stopping device in the neutral position corresponding to the open position of the driven member. By applying the second switching torque to the drive member, larger than the second drive torque, the movable element is forced by the drive member to cause deflection of the stopping device such that the movable element moves from the first region to the second region. The stopping device is thereby switched from the first state to the second state.

When the stopping device adopts the second state, the drive member can be rotated continuously with a plurality of full rotations in the second direction, e.g. for driving the driven member to rotate the nut in a counterclockwise direction. By rotating the drive member in the first direction with a first drive torque when the stopping device adopts the second state, the drive member will eventually be stopped by the stopping device in the neutral position. By applying the first switching torque to the drive member, larger than the first drive torque, the movable element is forced by the drive member to cause deflection of the stopping device such that the movable element moves from the second region back to the first region. The stopping device is thereby switched from the second state back to the first state.

The arrangement thus enables the driven member to do both tightening and loosening of the nut without needing a sensor for determining a position of the drive member and/or the driven member. Correspondingly, the arrangement also enables the driven member to do both clockwise and counterclockwise tightening of the nut.

Due to the functionality of the arrangement, there is no need to produce two different arrangements, one for clockwise tightening and one for counterclockwise tightening. The arrangement therefore enables fewer variants of the arrangement to be manufactured and held in stock.

The movable element may be a free body with respect to the base structure, the drive member and the remainder of the stopping device. The movable element may be movable relative to the limiting element. Alternatively, the movable element may be connected to the limiting element or to another part of the arrangement.

The drive member may be rotatable about a drive axis. Each of the first and second directions may be rotational directions about the drive axis and the second direction may be opposite to the first direction.

The drive member may be concentric with the drive axis. The drive axis may be parallel with the driven axis. The stopping device except the movable element may be symmetric with respect to a plane comprising the drive axis.

The base structure may be fixed with respect to a main body of the power tool. Thus, in case the power tool is held stationary, also the base structure is stationary. For this reason, the base structure may be referred to as a stationary structure.

The base structure, the drive member and the stopping device may lie in a common plane transverse to the drive axis. The base structure may fully or at least partly surround the drive member, e.g. by enclosing at least <NUM> degrees of the drive member (with respect to the drive axis). The stopping device may be positioned between the base structure and the drive member.

The arrangement may further comprise a constriction between the limiting element and the drive member. In this case, the movable element is positioned on a first side of the constriction in the first state and on a second side of the constriction in the second state. The movable element may be arranged to be stopped by the constriction when the second drive torque is applied to the drive member in the first state. When the second switching torque is applied to the drive member in the first state, the movable element passes through the constriction. The movable element may be arranged to be stopped by the constriction when the first drive torque is applied to the drive member in the second state. When the first switching torque is applied to the drive member in the second state, the movable element passes through the constriction.

The constriction may alternatively be referred to as a narrowing. The constriction may be configured to be widened by the deflection of the stopping device.

The stopping device may comprise at least one elastic element. In this case, the stopping device may be configured to deflect by deformation of the at least one elastic element when the stopping device switches from the first state to the second state and/or from the second state to the first state. When the elastic element deforms, the moveable element can pass the limiting element and move from the first to second region and vice versa. The at least one elastic element may comprise a stopping spring, such as a blade spring or a coil spring, of the limiting element. Alternatively, or in addition, the movable element may be elastic and thereby constitute one elastic element of the at least one elastic element. One or more of the at least one elastic element may also optionally be constituted by an elastic part of the base structure.

The base structure may comprise a first chamber for receiving the movable element in the first state and a second chamber for receiving the movable element in the second state. In this case, the limiting element may be arranged between the first chamber and the second chamber. When the stopping device adopts the first state and the drive member rotates in the first direction, the drive member pushes the movable element into the first chamber. Conversely, when the stopping device adopts the second state and the drive member rotates in the second direction, the drive member pushes the movable element into the second chamber.

The stopping device may comprise a first force device associated with the first chamber and arranged to force the movable element towards the drive member in the first state, and a second force device associated with the second chamber and arranged to force the movable element towards the drive member in the second state.

The first force device may be positioned in the first chamber and the second force device may be positioned in the second chamber. Each of the force device may be a magnet or a spring, such as a compression coil spring, a blade spring, or a leg of a blade spring. As a possible alternative, one or each of the first and second force devices may be omitted and the movable element can be forced towards the drive member by means of gravity.

The drive member may comprise an engaging structure arranged to engage the movable element in the neutral position in each of the first state and the second state. Thus, regardless of whether the stopping device is in the first or second state, the engaging structure can force the movable element against the limiting element when the drive member adopts the neutral position.

The engaging structure may comprise a recess. A width of the recess in a circumferential direction with respect to the drive axis may be at least <NUM> times, such as twice, a width of the movable element in the circumferential direction. Alternatively, or in addition, the engaging structure may comprise one or more protrusions. One example of such protrusion is a wedge.

The movable element may comprise a ball. The ball may be rigid, for example by being made of metal or hard plastic. Alternatively, the ball may be elastic and hence be used as an elastic element of the stopping device. In any case, the ball may be spherical.

According to a second aspect, there is provided a tool head for a power tool, the tool head comprising the arrangement according to the first aspect. The tool head may be detachably attachable to a main body of the power tool.

The tool head may further comprise a driven axis; a base element having a base opening; a driven member having a driven member opening, the driven member being rotatable about the driven axis from an open position where the driven member opening is aligned with the base opening; and a drive transmission arranged to transmit a rotation of the drive member to a rotation of the driven member; wherein the drive transmission is configured such that the neutral position of the drive member corresponds to the open position of the driven member.

According to a third aspect, there is provided a power tool comprising the tool head according to the second aspect. The power tool may be an open end power tool as described herein. The power tool may for example be an electric, hydraulic or pneumatic power tool. Alternatively, or in addition, the power tool may be a tightening tool, e.g. for tightening a nut on a threaded member. Alternatively, or in addition, the power tool may be handheld.

The power tool may further comprise a control system, the control system comprising at least one data processing device and at least one memory having at least one computer program stored thereon, the at least one computer program comprising program code which, when executed by the at least one data processing device, causes the at least one data processing device to perform the steps of commanding the drive member to generate a second drive torque in the second direction against the stopping device in the neutral position of the drive member when the stopping device adopts the first state; commanding the second drive torque to increase to a second switching torque where the stopping device switches from the first state to the second state; and storing a second threshold value indicative of the second switching torque.

The at least one computer program may further comprise program code which, when executed by the at least one data processing device, causes the at least one data processing device to perform the steps of commanding the drive member to generate a first drive torque in the first direction against the stopping device in the neutral position of the drive member when the stopping device adopts the second state; commanding the first drive torque to increase to a first switching torque where the stopping device switches from the second state to the first state; and storing a first threshold value indicative of the first switching torque.

In order to cause the drive member to generate the second drive torque, the drive member may be controlled to rotate at a target rotational speed. Once the drive member is stopped by the stopping device in the neutral position, the second drive torque will increase and the driving of the drive member can then be stopped, e.g. when the second drive torque reaches the first counter torque (or a torque value slightly below the first counter torque). In order to switch the stopping device from the first state to the second state, the torque on the drive member is allowed to increase to the second switching torque without stopping the drive member. The foregoing applies vice versa for the first drive torque and the first switching torque to switch from the second state to the first state.

Thus, the control system may be configured to carry out a tuning process where information regarding drive torques for overcoming friction and other forces to drive the drive member to the neutral position without causing switching, and regarding switching torques for switching the stopping device between the first and second states, can be stored and subsequently used. The control system thereby knows which drive torques can be used without switching, and which switching torque is required for switching to each of the first and second states. The tuning process may be performed automatically, for example at predefined intervals. Alternatively, or in addition, threshold values indicative of the switching torques may be stored each time the stopping device switches between the first and second states.

The control system according to this aspect enables efficient updating of the switching torques. The arrangement can thereby efficiently compensate for changed characteristics of the arrangement (e.g. due to wear) and can reliably ensure that no inadvertent switching between the first and second states takes place. The control system may be physically located in a main body of the power tool.

The power tool may further comprise a state selection element for alternatingly selecting between the first state and the second state; and a driving command element for alternatingly commanding rotation of the drive member in the first direction and in the second direction. When the stopping device adopts the first state and the driving command element is actuated a first time (for example pushed a first time), the drive member rotates in the first direction. When the driving command element is actuated a second time (for example pushed a second time), the drive member rotates in the second direction and stops in the neutral position. By actuating the state selection element, the drive member is driven to switch the stopping device from the first state to the second state. The driving command element can now be actuated a first time and a second time to cause driving of the drive member in the second direction and in the first direction back to the neutral position, respectively.

According to a fourth aspect, there is provided a method of controlling an arrangement for a power tool, where the arrangement comprises a base structure; a drive member rotatable relative to the base structure in a first direction and in a second direction from a neutral position; a stopping device comprising a movable element and a limiting element; wherein the stopping device is arranged to adopt a first state where the movable element is in a first region with respect to the limiting element, and where the stopping device allows rotation of the drive member in the first direction and generates a first counter torque against rotation of the drive member in the second direction from the neutral position; wherein the stopping device is arranged to adopt a second state where the movable element is in a second region with respect to the limiting element, and where the stopping device allows rotation of the drive member in the second direction and provides a second counter torque against rotation of the drive member in the first direction from the neutral position; and wherein the stopping device is deflectable to switch from the first state to the second state by rotating the drive member in the second direction from the neutral position with a second switching torque overcoming the first counter torque; the method comprising commanding the drive member to generate a second drive torque in the second direction against the stopping device in the neutral position of the drive member when the stopping device adopts the first state; commanding the second drive torque to increase to the second switching torque where the stopping device switches from the first state to the second state; and storing a second threshold value indicative of the second switching torque. The method may further comprise commanding the drive member to generate a first drive torque in the first direction against the stopping device in the neutral position of the drive member when the stopping device adopts the second state; commanding the first drive torque to increase to a first switching torque where the stopping device switches from the second state to the first state; and storing a first threshold value indicative of the first switching torque. The arrangement in the method of the fourth aspect may be of any type according to the first aspect.

Further details, advantages and aspects of the present disclosure will become apparent from the following description taken in conjunction with the drawings, wherein:.

In the following, an arrangement for a power tool, a tool head for a power tool, a power tool, and a method of controlling an arrangement for a power tool, will be described. The same or similar reference numerals will be used to denote the same or similar structural features.

<FIG> schematically represents a side view of a power tool <NUM>, and <FIG> schematically represents a top view of the power tool <NUM>. With collective reference to <FIG>, the power tool <NUM> comprises a main body <NUM> and a tool head <NUM>. The tool head <NUM> is detachably attached to the main body <NUM>.

The power tool <NUM> of this example is a handheld open end power tool for tightening. The power tool <NUM> may for example be driven electrically. As shown in <FIG>, the power tool <NUM> can for example be used to tighten or loose a nut <NUM> threaded on a threaded coupling <NUM>. The threaded coupling <NUM> may in turn enclose a pipe <NUM>.

The power tool <NUM> of this example further comprises a driving command element <NUM> and a state selection element <NUM> arranged at the main body <NUM>. The driving command element <NUM> is here exemplified as a lever rotatable relative to the main body <NUM>. The state selection element <NUM> is here exemplified as a button.

The tool head <NUM> comprises a base element <NUM>. The base element <NUM> comprises a base opening <NUM> at a distal end thereof.

The tool head <NUM> further comprises a driven member <NUM> having a driven member opening <NUM>. The driven member <NUM> is rotatable relative to the base element <NUM> about a driven axis <NUM>. In <FIG>, the driven member <NUM> is in an open position <NUM>. In the open position <NUM>, the driven member opening <NUM> is aligned with the base opening <NUM> and can thereby receive the nut <NUM> in a radial direction with respect to the driven axis <NUM>. Alternatively, the pipe <NUM> may be received through the driven member opening <NUM> in the open position <NUM>, and the power tool <NUM> may then be moved axially along the pipe <NUM> to axially receive the nut <NUM> in the driven member opening <NUM>.

The tool head <NUM> further comprises an arrangement <NUM>. By means of the arrangement <NUM>, the driven member <NUM> can rotate clockwise about the driven axis <NUM>, rotate counterclockwise about the driven axis <NUM>, and can be positioned in the open position <NUM> from each of the clockwise direction and the counterclockwise direction.

In this implementation, a first push of the driving command element <NUM> causes clockwise rotation of the driven member <NUM>, and a second push of the driving command element <NUM> causes counterclockwise rotation of the driven member <NUM> back to the open position <NUM>. A push on the state selection element <NUM> causes a switch such that a subsequent first push of the driving command element <NUM> causes counterclockwise rotation of the driven member <NUM>, and a subsequent second push of the driving command element <NUM> causes clockwise rotation of the driven member <NUM> back to the open position <NUM>.

<FIG> schematically represents a side view of the power tool <NUM> when the tool head <NUM> is detached from the main body <NUM>. As shown in <FIG>, the main body <NUM> of this example comprises a drive shaft <NUM>. The drive shaft <NUM> is rotatable about a drive axis <NUM>. In this example, the drive axis <NUM> is parallel with the driven axis <NUM> when the tool head <NUM> is attached to the main body <NUM>.

The power tool <NUM> of this example further comprises a control system <NUM>. The control system <NUM> is here provided in the main body <NUM>. The control system <NUM> comprises a data processing device <NUM> and a memory <NUM>. The memory <NUM> has a computer program stored thereon. The computer program comprises program code which, when executed by the data processing device <NUM>, causes the data processing device <NUM> to perform, or command performance of, various steps as described herein.

The main body <NUM> further comprises a motor <NUM> and a motor transmission <NUM>. The motor transmission <NUM> is configured to transmit a rotation of the motor <NUM> to a rotation of the drive shaft <NUM> in a manner previously known as such. The control system <NUM> is in signal communication with the motor <NUM>. The control system <NUM> is configured to control a rotational direction and a torque of the drive shaft <NUM>.

<FIG> schematically represents a cross-sectional side view of the tool head <NUM>, and <FIG> schematically represents a top view of components of the tool head <NUM>. With collective reference to <FIG>, the arrangement <NUM> comprises a drive member <NUM>. The drive member <NUM> is rotatable about the drive axis <NUM> relative to the base element <NUM>. The drive member <NUM> is here exemplified as a hollow shaft arranged to receive the drive shaft <NUM> for being driven thereby.

The arrangement <NUM> further comprises a base structure <NUM>. The base structure <NUM> is fixed to the base element <NUM>.

The tool head <NUM> further comprises a drive transmission <NUM>. The drive transmission <NUM> is configured to transmit a rotation of the drive member <NUM> about the drive axis <NUM> to a rotation of the driven member <NUM> about the driven axis <NUM>. In this example, the ratio between the drive member <NUM> and the driven member <NUM> is <NUM>:<NUM>. The drive transmission <NUM> of this specific example comprises a first gear wheel <NUM> in meshing engagement with a toothed portion of the drive member <NUM>, a second gear wheel <NUM> in meshing engagement with the first gear wheel <NUM>, a third gear wheel <NUM> in meshing engagement with the second gear wheel <NUM>, a primary fourth gear wheel 64a in meshing engagement with each of the third gear wheel <NUM> and a toothed portion of the driven member <NUM>, and a secondary fourth gear wheel 64b in meshing engagement with each of the third gear wheel <NUM> and the toothed portion of the driven member <NUM>.

<FIG> schematically represents a top view of one example of an arrangement 36a. The arrangement 36a may be used as the arrangement <NUM> in the power tool <NUM>. In addition to the drive member <NUM> and the base structure <NUM>, the arrangement 36a further comprises a stopping device 66a. The stopping device 66a is positioned between the drive member <NUM> and the base structure <NUM>. The stopping device 66a comprises a ball <NUM>, here exemplified as a spherical rigid metal ball. The ball <NUM> is one example of a movable element according to the present disclosure.

The stopping device 66a further comprises a stopping spring <NUM>, here exemplified as a blade spring. The stopping spring <NUM> is one example of a limiting element according to the present disclosure. The stopping spring <NUM> is also one example of an elastic element according to the present disclosure.

The stopping device 66a of this specific example further comprises a first spring <NUM> and a second spring <NUM>, here exemplified as compression coil springs. The first and second springs <NUM> and <NUM> are examples of first and second force devices, respectively, according to the present disclosure.

The base structure <NUM> comprises a first chamber <NUM> and a second chamber <NUM>. In this example, the first spring <NUM> is seated in a bottom of the first chamber <NUM> and the second spring <NUM> is seated in a bottom of the second chamber <NUM>. The stopping spring <NUM> is positioned generally between the first and second springs <NUM> and <NUM>. The base structure <NUM> of this specific completely surrounds the drive member <NUM>.

The drive member <NUM> of this example comprises a recess <NUM>. The recess <NUM> is one example of an engaging structure according to the present disclosure. The recess <NUM> has a depth substantially corresponding to half a diameter of the ball <NUM>. The recess <NUM> has a width in a circumferential direction with respect to the drive axis <NUM> that is approximately twice the diameter of the ball <NUM>.

In <FIG>, the drive member <NUM> is in a neutral position <NUM>. The drive transmission <NUM> is configured such that the neutral position <NUM> of the drive member <NUM> corresponds to the open position <NUM> of the driven member <NUM>.

<FIG> further shows that the stopping device 66a comprises a constriction <NUM> between the stopping spring <NUM> and the drive member <NUM>, here the recess <NUM> of the drive member <NUM>. In <FIG>, the constriction <NUM> is slightly smaller than the diameter of the ball <NUM>.

Furthermore, in <FIG>, the stopping device 66a is in a first state <NUM>. In the first state <NUM>, the ball <NUM> is positioned on a first side of the stopping spring <NUM> and the constriction <NUM> (the upper side in <FIG>). The first side is an example of a first region. In the neutral position <NUM> and the first state <NUM>, the ball <NUM> is received in a first part of the recess <NUM> (upper part in <FIG>) and is in contact with the stopping spring <NUM>. Furthermore, in the neutral position <NUM> and the first state <NUM>, each of the stopping device 66a (except the ball <NUM>), the drive member <NUM> and the base structure <NUM> is symmetric with respect to a central plane comprising the drive axis <NUM> (a horizontal plane through the drive axis <NUM> in <FIG>).

<FIG> schematically represents a top view of the arrangement 36a. In <FIG>, the drive member <NUM> rotates about the drive axis <NUM> in a first direction <NUM> with a first drive torque <NUM>, for example by pressing the driving command element <NUM> a first time. In the first state <NUM>, the stopping device 66a allows rotation of the drive member <NUM> in the first direction <NUM>.

As shown in <FIG>, the ball <NUM> is pushed into the first chamber <NUM> against deformation of the first spring <NUM> once the ball <NUM> leaves the recess <NUM>. When the stopping device 66a is in the first state <NUM> and the drive member <NUM> rotates in the first direction <NUM>, the drive member <NUM> and the stopping device 66a function as a freewheel. The drive member <NUM> can rotate continuously with several full turns in the first direction <NUM> to consequently cause the driven member <NUM> to rotate in a counterclockwise direction (as seen in <FIG>). Depending on the rotational speed, the ball <NUM> may be pushed into the recess <NUM> each time the recess <NUM> passes the first chamber <NUM>. However, further rotation of the drive member <NUM> causes the ball <NUM> to again leave the recess <NUM>. During rotation in the first direction <NUM>, the stopping device 66a in the first state <NUM> only generates a very small counter torque. The tightening torque applied to the nut <NUM> is therefore at most fractionally affected.

<FIG> schematically represents a top view of the arrangement 36a. In <FIG>, the drive member <NUM> has rotated about the drive axis <NUM> in a second direction <NUM> back to the neutral position <NUM> with a second drive torque <NUM>, for example by pressing the driving command element <NUM> a second time. The stopping device 66a generates a relatively small first counter torque <NUM> against further rotation of the drive member <NUM> as the ball <NUM> is squeezed by the recess <NUM> against the stopping spring <NUM> when the second drive torque <NUM> is applied to the drive member <NUM>. Thus, by rotating the drive member <NUM> in the second direction <NUM> with the second drive torque <NUM> when the stopping device 66a is in the first state <NUM>, the drive member <NUM> is stopped in the neutral position <NUM> and the driven member <NUM> is consequently stopped in the open position <NUM>.

<FIG> schematically represents a top view of the arrangement 36a. In <FIG>, the drive member <NUM> is in the neutral position <NUM>. A second switching torque <NUM> is now applied to the drive member <NUM>. The second switching torque <NUM> may be applied by pushing the state selection element <NUM>. The second switching torque <NUM> is larger than the second drive torque <NUM>. The second switching torque <NUM> will thereby cause the drive member <NUM> to push the ball <NUM> by means of the recess <NUM> against the stopping spring <NUM> such that the stopping spring <NUM> is enough deformed to cause the ball <NUM> to be pushed from the first side of the stopping spring <NUM>, through the constriction <NUM> and to a second side of the stopping spring <NUM>. The stopping device 66a thereby switches from the first state <NUM> to a second state. During this switching, the constriction <NUM> is temporarily widened due to the deformation of the stopping spring <NUM>. The second side is one example of a second region.

<FIG> schematically represents a top view of the arrangement 36a. In <FIG>, the stopping device 66a is in the second state <NUM>. The level of the second switching torque <NUM> when the ball <NUM> flips sides is stored as a second threshold value.

The drive member <NUM> rotates about the drive axis <NUM> in the second direction <NUM> with the second drive torque <NUM>, for example by pressing the driving command element <NUM> a first time. In the second state <NUM>, the stopping device 66a allows rotation of the drive member <NUM> in the second direction <NUM>.

As shown in <FIG>, the ball <NUM> is now pushed into the second chamber <NUM> against deformation of the second spring <NUM> once the ball <NUM> leaves the recess <NUM>. Also when the stopping device 66a is in the second state <NUM> and the drive member <NUM> rotates in the second direction <NUM>, the drive member <NUM> and the stopping device 66a function as a freewheel. The drive member <NUM> can rotate continuously with several full turns in the second direction <NUM> to consequently cause the driven member <NUM> to rotate in a clockwise direction (as seen in <FIG>).

<FIG> schematically represents a top view of the arrangement 36a. In <FIG>, the drive member <NUM> has rotated in the first direction <NUM> back to the neutral position <NUM> with the first drive torque <NUM>, for example by pressing the driving command element <NUM> a second time. In the neutral position <NUM> and the second state <NUM>, the ball <NUM> is received in a second part of the recess <NUM> (lower part in <FIG>) and is in contact with the stopping spring <NUM>. The stopping device 66a generates a relatively small second counter torque <NUM> against further rotation of the drive member <NUM> as the ball <NUM> is squeezed by the recess <NUM> against the stopping spring <NUM> when the first drive torque <NUM> is applied to the drive member <NUM>.

Thus, by rotating the drive member <NUM> in the first direction <NUM> with the first drive torque <NUM> when the stopping device 66a is in the second state <NUM>, the drive member <NUM> is stopped in the neutral position <NUM> and the driven member <NUM> is consequently stopped in the open position <NUM>. The arrangement 36a thus enables the driven member <NUM> to be rotated continuously in both clockwise and counterclockwise directions without needing a sensor for determining when the driven member <NUM> is in the open position <NUM>.

As can be gathered from <FIG> and <FIG>, the recess <NUM> is wide enough such that the ball <NUM> can be held in the recess <NUM> and pushed against the stopping spring <NUM> in the neutral position <NUM> in each of the first and second states <NUM> and <NUM> of the stopping device 66a.

<FIG> schematically represents a top view of the arrangement 36a. In <FIG>, the drive member <NUM> is in the neutral position <NUM>. A first switching torque <NUM> is now applied to the drive member <NUM> in the first direction <NUM>. The first switching torque <NUM> may be applied by pushing the state selection element <NUM>. The first switching torque <NUM> may be applied by pushing the state selection element <NUM>. The first switching torque <NUM> is larger than the first drive torque <NUM>. The first switching torque <NUM> will thereby cause the drive member <NUM> to push the ball <NUM> by means of the recess <NUM> against the stopping spring <NUM> such that the stopping spring <NUM> becomes enough deformed to cause the ball <NUM> to be pushed from the second side of the stopping spring <NUM>, through the constriction <NUM> and back to the first side of the stopping spring <NUM>. The stopping device 66a thereby switches from the second state <NUM> back to the first state <NUM>.

The level of the first switching torque <NUM> when the ball <NUM> flips sides is stored as a first threshold value. The first and second threshold values are then used for controlling subsequent switches between the first and second states <NUM> and <NUM> of the stopping device 66a. By updating the first and second switching torques <NUM> and <NUM>, the arrangement 36a can be regularly calibrated.

<FIG> schematically represents a top view of a further example of an arrangement 36b. The arrangement 36b has the same functionality as the arrangement 36a and may be used as the arrangement <NUM> in the power tool <NUM>. The arrangement 36b comprises a further example of a stopping device 66b.

The stopping device 66b is in the first state <NUM>. The drive member <NUM> is in the neutral position <NUM>. Mainly differences with respect to the stopping device 66a will be described.

The stopping device 66b of this example comprises a blade spring <NUM>. The blade spring <NUM> is a further example of a limiting element according to the present disclosure. The blade spring <NUM> is also a further example of an elastic element according to the present disclosure. The blade spring <NUM> comprises a first leg <NUM> and a second leg <NUM>. The first and second legs <NUM> and <NUM> are further examples of first and second force devices according to the present disclosure. The first leg <NUM> is positioned in the first chamber <NUM> and the second leg <NUM> is positioned in the second chamber <NUM>.

<FIG> schematically represents a top view of a further example of an arrangement 36c. The arrangement 36c has the same functionality as the arrangement 36a and may be used as the arrangement <NUM> in the power tool <NUM>. The arrangement 36c comprises a further example of a stopping device 66c. The stopping device 66c is in the first state <NUM>. The drive member <NUM> is in the neutral position <NUM>. Mainly differences with respect to the stopping device 66a will be described.

Instead of a ball, the stopping device 66c comprises a rod <NUM>. The rod <NUM> is a further example of a movable element according to the present disclosure.

The stopping device 66c further comprises a stopping spring <NUM>. The stopping spring <NUM> is a further example of a limiting element according to the present disclosure. The stopping spring <NUM> is also a further example of an elastic element according to the present disclosure. The stopping spring <NUM> enters a cavity <NUM> of the base structure <NUM>.

One end of the stopping spring <NUM> is connected to the base structure <NUM> and the other end of the stopping spring <NUM> is connected to the rod <NUM>. The stopping spring <NUM> of this example is a compression coil spring. The stopping device 66c of this example does not comprise a constriction.

Furthermore, instead of a recess, the drive member <NUM> in this example comprises a first wedge <NUM> and a second wedge <NUM>. The first and second wedges <NUM> and <NUM> are protrusions that constitute a further example of an engaging structure according to the present disclosure.

In the first state <NUM> and the neutral position <NUM>, the first wedge <NUM> engages the rod <NUM>. If the drive member <NUM> is rotated in the first direction <NUM>, the stopping spring <NUM> will push the rod <NUM> further out from the cavity <NUM> and the rod <NUM> will come into contact with the first spring <NUM>. Each time the first and second wedges <NUM> and <NUM> pass by the rod <NUM>, the rod <NUM> will be pushed against the first spring <NUM>.

When the drive member <NUM> is rotated in the second direction <NUM>, the first wedge <NUM> will eventually engage the rod <NUM> and push the rod <NUM> back to the position shown in <FIG> where the drive member <NUM> is in the neutral position <NUM>. If the second switching torque <NUM> is applied to the drive member <NUM>, the first wedge <NUM> will push the rod <NUM> further into the cavity <NUM> against further compression of the stopping spring <NUM> until the rod <NUM> flips sides.

<FIG> schematically represents a top view of a further example of an arrangement 36d. The arrangement 36d has the same functionality as the arrangement 36a and may be used as the arrangement <NUM> in the power tool <NUM>. The arrangement 36d comprises a further example of a stopping device 66d. The stopping device 66d is in the first state <NUM>. The drive member <NUM> is in the neutral position <NUM>. Mainly differences with respect to the stopping device 66a will be described.

The stopping device 66d of this example comprises a first magnet <NUM> and a second magnet <NUM>. The first and second magnets <NUM> and <NUM> are further examples of force devices according to the present disclosure. The first magnet <NUM> is housed in the first chamber <NUM> and the second magnet <NUM> is housed in the second chamber <NUM>. Each of the first and second magnets <NUM> and <NUM> is configured to generate a repulsive magnetic force on the ball <NUM> to thereby force the ball <NUM> towards the drive member <NUM>.

The stopping device 66d of this example further comprises a flipping member <NUM>. The flipping member <NUM> is a further example of a limiting element according to the present disclosure. The flipping member <NUM> is here T-shaped. The flipping member <NUM> is rotatable about a flipping axis <NUM>. The flipping member <NUM> comprises a magnetic target section <NUM>, here at the bottom of the T-shape.

The stopping device 66d of this example further comprises a first flipping magnet <NUM> and a second flipping magnet <NUM>. The target section <NUM> is arranged between the first and second flipping magnets <NUM> and <NUM> in each of the first state <NUM> and the second state <NUM> of the stopping device 66d. Each of the first and second flipping magnets <NUM> and <NUM> is configured to generate an attractive magnetic force on the target section <NUM>.

By applying the second drive torque <NUM> to the drive member <NUM> in the neutral position <NUM> when the stopping device 66d adopts the first state <NUM>, the drive member <NUM> pushes the ball <NUM> against the flipping member <NUM>. A rotational torque about the flipping axis <NUM> (clockwise in <FIG>) is thereby generated. However, this rotational torque is counteracted by the attraction of the target section <NUM> by the second flipping magnet <NUM>. When the second drive torque <NUM> is increased to provide the second switching torque <NUM>, the attractive force between the target section <NUM> and the second flipping magnet <NUM> is overcome and the flipping member <NUM> is caused to rotate about the flipping axis <NUM> (in a clockwise direction in <FIG>) until the target section <NUM> is magnetically attracted to the first flipping magnet <NUM>. The ball <NUM> is then allowed to pass from the first region to the second region. In this way, the stopping device 66d can switch from the first state <NUM> to the second state <NUM> (and vice versa) by deflection of the flipping member <NUM>.

<FIG> schematically represents a top view of a further example of an arrangement 36e. The arrangement 36e has the same functionality as the arrangement 36a and may be used as the arrangement <NUM> in the power tool <NUM>. The arrangement 36e comprises a further example of a stopping device 66e. The stopping device 66e is in the first state <NUM>. Mainly differences with respect to the stopping device 66a will be described.

Instead of the stopping spring <NUM> (see <FIG>), a rigid bulge <NUM> protrudes from the base structure <NUM> towards the drive member <NUM>. The bulge <NUM> is a further example of a limiting element according to the present disclosure.

Furthermore, instead of the rigid ball <NUM>, the stopping device 66e comprises an elastic ball <NUM>. The ball <NUM> is a further example of a movable element according to the present disclosure. The ball <NUM> is also a further example of an elastic element according to the present disclosure. <FIG> shows the ball <NUM> in an undeformed state (with a dashed circle) and the ball <NUM> in a compressed state (with a solid circle).

When the second switching torque <NUM> is provided to the drive member <NUM>, the ball <NUM> is squeezed to compress between the recess <NUM> and the bulge <NUM>. When the ball <NUM> is compressed, the ball <NUM> can pass through the constriction <NUM>. In this way, the stopping device 66e can switch from the first state <NUM> to the second state <NUM> (and vice versa).

The elastic ball <NUM> may replace the rigid ball <NUM> in any of the arrangements 36a-36d. Thus, the stopping device 66a-66d may comprise more than one elastic element.

Claim 1:
An arrangement (<NUM>; 36a-36e) for a power tool (<NUM>), the arrangement (<NUM>; 36a-36e) comprising:
- a base structure (<NUM>);
- a drive member (<NUM>) rotatable relative to the base structure (<NUM>) in a first direction (<NUM>) and in a second direction (<NUM>) from a neutral position (<NUM>);
- a stopping device (<NUM>; 66a-66e) comprising a movable element (<NUM>; <NUM>; <NUM>) and a limiting element (<NUM>; <NUM>; <NUM>; <NUM>; <NUM>);
wherein the stopping device (<NUM>; 66a-66e) is arranged to adopt a first state (<NUM>) where the movable element (<NUM>; <NUM>; <NUM>) is in a first region with respect to the limiting element (<NUM>; <NUM>; <NUM>; <NUM>; <NUM>), and where the stopping device (<NUM>; 66a-66e) allows rotation of the drive member (<NUM>) in the first direction (<NUM>) and generates a first counter torque (<NUM>) against rotation of the drive member (<NUM>) in the second direction (<NUM>) from the neutral position (<NUM>);
wherein the stopping device (<NUM>; 66a-66e) is arranged to adopt a second state (<NUM>) where the movable element (<NUM>; <NUM>; <NUM>) is in a second region with respect to the limiting element (<NUM>; <NUM>; <NUM>; <NUM>; <NUM>), and where the stopping device (<NUM>; 66a-66e) allows rotation of the drive member (<NUM>) in the second direction (<NUM>) and provides a second counter torque (<NUM>) against rotation of the drive member (<NUM>) in the first direction (<NUM>) from the neutral position (<NUM>); and
characterised in that
the stopping device (<NUM>; 66a-66e) is deflectable to switch from the first state (<NUM>) to the second state (<NUM>) by rotating the drive member (<NUM>) in the second direction (<NUM>) from the neutral position (<NUM>) with a second switching torque (<NUM>) overcoming the first counter torque (<NUM>).