Patent Application
20250069822
The present application claims priority to European Patent Application No. EP 23192793.0 filed on Aug. 22, 2023, which is herein incorporated by reference in its entirety.
The present disclosure relates to activation switches for powered devices, such as power tools or garden equipment.
Some power tools include a motor, for example for driving a reciprocating or oscillating load. Such tools are often used to perform compacting tasks such as compacting soil, asphalt or hardcore, or hammering tasks such as breaking up concrete (e.g. a jack hammer). An example of a compacting power tool is a rammer which comprises a reciprocating foot which impacts and flattens the surface to be compacted. A rammer may also be known as a tamper, a soil compactor, a compactor, a jumping jack compactor, a jumping jack tamper. Another example of a compacting power tool is a plate compactor, which is also known as a vibratory plate. Rammers or plate compactors generally comprise an electric motor for driving the reciprocating foot or plate. Battery-operated devices such as rammers and plate compactors commonly have an electric drive that is switched on and off via a switch. Accidental operation of the switch can be dangerous and may result in injury of an operator.
It is desirable for the switch to include a mechanism that prevents accidental operation of the device and that allows the device to be easily deactivated when desired.
According to a first aspect, there is provided a mechanism for operating a switch for a powered device, the mechanism comprising a first manually operable member and a second manually operable member, the mechanism being configured to activate the switch in response to a first motion and a different second motion of the first manually operable member, wherein the second manually operable member is configured to move in response to the second motion of the first manually operable member.
The two-stage activation of the switch using the mechanism may prevent the accidental activation of a powered device. This may improve the safety of such devices, particularly devices having heavy or sharp moving components.
The switch may not be activated after the first motion of the first manually operable member. The mechanism may be configured to activate the switch following the second motion of the first manually operable member. The second manually operable member may be configured to directly activate the switch. It may do this by bearing against an actuator of the switch.
The second motion of the first manually operable member may only be achieved after the first motion. This may help to avoid accidental operation of the switch.
The mechanism may be configured to deactivate the switch in response to a deactivation motion of the second manually operable member. The deactivation motion of the second manually operable member may be a translation. The deactivation motion of the second manually operable member may be a single motion. This may allow the switch to be easily deactivated.
The second manually operable member may be configured to move in response to the second motion of the first manually operable member. The second manually operable member may be configured to not move in response to the first motion of the first manually operable member. This may allow the switch to be activated only in response to the second motion, which is performed after the first motion.
The mechanism may be configured to activate the switch in response to movement of the second manually operable member. This may allow the first manually operable member to indirectly activate the switch.
The first motion of the first manually operable member may be a rotation of the first manually operable member. This may help to ensure that the first motion is only performed intentionally by a user.
The second motion of the first manually operable member may be a translation of the first manually operable member. Using a rotation followed by a translation of the first manually operable member to activate the switch may further help to avoid accidental activation of the switch.
The second motion of the first manually operable member may be a translation in a direction perpendicular to an axis about which the first manually operable member is configured to rotate. This may be a convenient mechanism.
The first motion of the first manually operable member may be a translation of the first manually operable member. The first motion of the first manually operable member may be a translation in a different direction to the second motion (if the second motion is also a translation). The use of two different translational motions (for example, requiring the user to push and then slide the first manually operable member) may help to avoid accidental activation of the switch.
The mechanism may be a safety mechanism. The two-stage activation of the switch using the mechanism may reduce the chance of an injury occurring during the use of a powered device incorporating the switch.
The first motion may comprise moving the first manually operable member from a first configuration to a second configuration. The second motion may comprise moving the first manually operable member from the second configuration to a third configuration. The second motion of the first manually operable member may cause the second manually operable member to move from a first, deactivated configuration to a second, activated configuration. The deactivation motion of the second manually operable member may comprise moving the further manually operable member from the activated configuration to the deactivated configuration.
The mechanism may comprise one or more resilient elements configured to bias the first manually operable member towards the first configuration. The mechanism may comprise one or more resilient elements configured to bias the second manually operable member in its deactivated configuration. This may avoid accidental activation by requiring a user to overcome the force of the resilient element to activate the switch.
The second manually operable member may have a lower resistance to motion than the first manually operable member. This may allow the switch to be deactivated more easily compared to activating the switch. This may act as a safety feature.
The first manually operable member may be configured to engage an intermediate member configured to move relative to a housing of the mechanism. The intermediate member may be configured to rotate relative to the housing. The intermediate member may be rotatably connected to the housing. The intermediate member may be contained within the housing.
The intermediate member may be configured to engage the second manually operable member. This may allow motion of the second manually operable member to be driven via the intermediate member.
The intermediate member may be fast with the first manually operable member and/or the second manually operable member. The intermediate member may be integrally formed with the first manually operable member and/or the second manually operable member. This may be convenient for manufacturing of the mechanism.
The intermediate member may be configured to move (for example, rotate) in response to the second motion of the first manually operable member to drive motion of the second manually operable member. This may allow the second manually operable member to be driven in response to the second motion of the first manually operable member.
The switch may comprise a micro switch responsive to motion of the second manually operable member. The micro switch may be activated in response to motion of the second manually operable member. The micro switch may be deactivated in response to the deactivation motion of the second manually operable member. This may allow a power switch circuit of the powered device to be connected to a power supply.
The first manually operable member and the second manually operable member may be fast with each other. The first manually operable member may be configured to move with the second manually operable member. For example, the members may both be attached to a plate, such that motion of the first manually operable member directly causes motion of the second manually operable member. The first manually operable member and the second manually operable member may be formed unitarily. The first manually operable member and the second manually operable member may be integrally formed. This may be convenient for manufacturing of the mechanism.
The switch may be configured to close a power switch circuit that supplies power from a power source to a motor of the powered device. Alternatively, the switch may be configured to send a signal for activating/deactivating the motor of the powered device. This may allow the powered device to be turned on.
According to a further aspect, there is provided a powered device comprising the mechanism of any preceding claim. The device may be a power tool, such as a rammer, or a piece of garden equipment, such as a lawnmower. Such devices may have heavy or sharp moving parts. The mechanism may prevent such devices from being accidentally activated.
The powered device may be a rammer or a plate compacter. The powered device may have a handle. The mechanism may be mounted to the handle.
The powered device may comprise a removable control comprising: the mechanism; and a switch for operation by the mechanism. This may allow the device to be remotely activated and/or deactivated.
The above features may be combined as appropriate, as would be apparent to a skilled person, and may be combined with any of the aspects of the examples described herein.
The accompanying drawings illustrate various examples. Common reference numerals are used throughout the figures, where appropriate, to indicate similar features.
The following description is presented by way of example to enable a person skilled in the art to make and use the invention. The present invention is not limited to the embodiments described herein and various modifications to the disclosed embodiments will be apparent to those skilled in the art.
The present disclosure describes a rammer by way of example. More generally, the powered device may be any kind of powered device, such as plate compactors, vibratory rollers and lawn mowers.
As an example of a power tool,
The connecting rod 216 and the reciprocating piston 232 are arranged to move along the longitudinal axis within a piston cylinder 1908. The piston cylinder 1908 receives and guides the movement of the reciprocating piston 232 when moving along the longitudinal axis. The distal end 218 of the piston cylinder 1908, located away from the primary housing 102, is connected to the compacting foot 112 such that movement of the reciprocating mechanism 200 results in movement of the compacting foot 112.
In some examples, the reciprocating piston 232 is coupled to a spring assembly comprising a first spring 1904 and a second spring 1906. When the rammer 100 is not operational, the reciprocating mechanism 200 rests in the position as shown in
The arrangement of springs 1904 and 1906 in
The reciprocating leg portion 110 (comprising the piston cylinder 1908 and spring assembly) and the reciprocating foot 112 form a lower mass assembly 250 which reciprocates with respect to an upper mass assembly 260. The upper mass assembly 260 is formed by the remaining components of the rammer 100 in the primary housing 102 (e.g. its motor, eccentric wheel drive, battery pack, etc.). In other words, the lower mass assembly 250 includes those parts of the rammer connected to end 210 of the connecting rod 216 and which therefore move in a reciprocal motion relative to the upper mass assembly 260. The upper mass assembly 260 is in some examples is all the other components which are not part of the lower mass assembly 250.
As shown in
In some examples, the eccentric drive wheel 236 may be coupled to the drive shaft 226 of the motor 204 via a pinion gear mounted on the drive shaft 226 which is arranged to engage with a toothed outer surface (not shown) of the eccentric drive wheel 236 so as to rotate the drive wheel.
Various other mechanical arrangements for converting a rotational movement into a reciprocating movement are known in the art and any suitable such arrangement may be used.
In
A brushless direct current (BLDC) motor may be used in which the motor is directly coupled (optionally via a transmission) to a reciprocating mechanism without a clutch (e.g. a centrifugal clutch). In this manner, rotation of the motor corresponds to movement of the reciprocating mechanism and its mechanical load through the reciprocating cycle.
A power source is provided to power the motor 204 and its control apparatus. The power source may be a battery, for example a replaceable battery pack. In order to drive the motor, the control logic is configured to control a power switch circuit which provides voltage and current from the power source to the motor 204 under the control of the control logic. A switch 400, 500 is provided for providing the control logic with an activation or deactivation signal. In alternative embodiments, the switch may be located such that it can open and close the supply of power from the battery to the motor.
The present disclosure describes a mechanism for operating a switch 400, 500 which, in contrast to a conventional switch mechanism, prevents unintentional actuation by means of a two-stage activation and thus acts as a safety mechanism. At the same time, the mechanism can offer the user a high level of comfort.
Components of the switch are accommodated in a housing 401. Part(s) of some of the components, such as the manually operable members described below, may protrude from the housing so that they can be operated by a user. The manually operable members described herein can be operated by a user without the need for tools (i.e. they may be hand operable). For example, a user may operate a member by applying a force to it with one or more of their fingers, causing the first member 402 to move relative to the housing 401.
In this example, the switch mechanism comprises a manually operable member 402. The manually operable member 402 is a first manually operable member. The mechanism is configured to activate the switch (to send an activation signal to the control logic or to close the circuit that supplies power from the power source to the motor) in response to a first motion and a different second motion of the first manually operable member 402.
The mechanism also comprises a further manually operable member 403. The further manually operable member 403 is a second manually operable member. The mechanism is configured to deactivate the switch (to send a deactivation signal to the control logic or to open the circuit that supplies power from the power source to the motor) in response to a deactivation motion of the second manually operable member 403. The deactivation motion is preferably a single motion.
The first motion of the first member 402 comprises movement of the first member 402 from a first configuration to a second configuration. In this example, the first and second configurations of the first member 402 are shown in
The first and second motions are sequential motions. The second motion follows the first motion. The second motion of the first manually operable member 402 can only be performed after the first motion. For example, the second motion of the first member 402 may only be able to be performed once the first member 402 is in its second configuration, following completion of the first motion.
In other implementations, the first motion may comprise a different type of motion. For example, the first motion may be a translation of the first manually operable member 402.
In this implementation, the second member 403 does not move in response to the first motion of the first member 402. As shown in
The mechanism comprises an intermediate member 406. The intermediate member is configured to engage the first 402 and second 403 members. In this example, the intermediate member 406 is rotatably attached to the housing 401 and rotates about an axis indicated at 407. Protrusions at opposing ends of the intermediate member 406 engage corresponding recesses in the members 402, 403. The intermediate member may not move in response to the first motion of the first member 402. Specifically, the intermediate member may not rotate in response to the first motion of the first member 402. The intermediate member 406 is configured to move in response to the second motion of the first manually operable member 402 to drive motion of the second manually operable member 403. Specifically, the intermediate member 406 is configured to rotate (about axis 407 in this example) in response to the second motion of the first manually operable member 402 to drive motion of the second manually operable member 403.
The mechanism is configured to activate the switch in response to the second motion of the first manually operable member.
The first member 402 is prevented from moving beyond the third configuration by a stop, for example by the edge of a cut-out in the first member 402 that also allows the first member to pivot about axis 404. The second member may also be prevented from moving beyond its activated configuration by a stop or a catch. In the example shown in
The switch arrangement comprises at least one micro switch 408 responsive to motion of the second manually operable member 403. In other words, the second member directly actuates the switch. The first member does not directly actuate the switch, but causes movement of the second member that actuates the switch. In other words, the first member 402 indirectly activates the switch. The second member may be in contact with an actuator 414 of the switch. Movement of the second member from its deactivated configuration to its activated configuration causes the switch to be activated.
A second micro switch may be provided. As shown in
The intermediate member 406 moves in response to the second motion of the first member 402. In this example, the intermediate member 406 rotates in response to the second motion of the first member 402. When the first member 402 moves from its second configuration to its third configuration, the intermediate member rotates about axis 407 and drives the second member 403 to move upwards relative to the housing 401. The rotation of the intermediate member as the first member moves from its second configuration to its third configuration drives the second member 403 to move from its deactivated configuration to its activated configuration. This single motion of the second member causes the activation of micro switch 408. The second member 403 operates an actuator 414 of the micro switch to cause the switch to be activated as it moves from its deactivated configuration to its activated configuration. This can be used indicate to the control logic to activate the powered device or to close the circuit that supplies power from the power source to the motor of the powered device.
In its activated configuration, the second member 403 may protrude from the housing 401. In the example shown in
In this example, the second motion of the first member 402 is a translation. The second motion is a linear motion. The direction of motion may be at an angle to a longitudinal axis of the housing 401. In this specific example, the second motion is a translation in a direction perpendicular to the axis 404 about which the first manually operable member is configured to rotate.
The second manually operable member 403 is configured to move in response to the second motion of the first manually operable member 402. The mechanism is configured to activate the switch 408 in response to movement of the second manually operable member. In this example, the activation motion of the second member is a translation. The activation motion of the second member is preferably a single motion. The direction of motion may be parallel to the longitudinal axis of the housing. The second member moves between a first configuration and a second configuration to activate the switch. The second motion of the first member causes the activation motion of the second member.
To deactivate the switch, the second member can be moved from the second, activated configuration to return to the first, deactivated configuration. The deactivation motion is preferably a single motion. In this example, the first and second configurations are respective positions of the second member 403 relative to the housing 401 of the switch unit.
The mechanism may comprise one or more resilient elements to bias the first manually operable member towards the deactivated position. In this example, the mechanism comprises a pin 409 and a spring 410 which biases the first member towards the first configuration. In
There may be no added resistance to the second motion (i.e. beyond the inherent resistance of the mechanism). That is, there may not be a resilient element that biases the first member in the second configuration. Therefore, there may be increased resistance to the first motion of the first member, but no increased resistance to the second motion of the first member.
The resilient element acting on the second member resists motion of the second member away from its first, deactivated configuration, and so, via the intermediate member, also acts to resist the second motion of the first member. In some examples, resistance to the second motion of the first member may be provided in this way, without a separate resilient member at the first member for resisting the second motion.
The mechanism may also comprise a further resilient element, such as spring 411, configured to bias the second manually operable member towards the deactivated position (i.e. in its first configuration). When the user presses the second member downwards, to perform the deactivation motion in this example, the spring 411 assists the motion of the second member to deactivate the micro switch. The resilient element therefore biases the second member towards its deactivated configuration.
The second manually operable member 403 may generally have a lower resistance to motion than the first manually operable member 402. This can assist in preventing accidental activation of the powered device.
In this example, the mechanism for operating the switch comprises a first manually operable member 502. The mechanism is configured to activate the switch in response to a first motion and a different second motion of the first manually operable member 502.
In this example, the first motion is a translation and the second motion is a translation. The first motion is a translation in a direction perpendicular to the plane of the housing (i.e. the button is pushed into the plane of the housing). The second motion is a translation parallel to the plane of the housing (i.e. the button is slid parallel to the plane of the housing).
The mechanism also comprises a second manually operable member 503. The mechanism is configured to deactivate the switch in response to a deactivation motion of the second manually operable member 503. The single motion is a translation parallel to the plane of the housing. The deactivation motion may be in a direction opposite to that of the second motion of the first member. The deactivation motion is preferably a single motion.
In this example, the first and second members are both fast with a plate 504 that moves within the housing 501 in response to motion of the first 502 and second 503 members. The plate 504 and the first 502 and second 503 members may be integrally formed.
To perform the first motion, a user can push the member 502 into the plane of the housing 501 (either perpendicularly or at an oblique angle). To perform the second motion, the user can slide the member 502 upwards, for example parallel to the plane of the housing, or nearly parallel to the plane of the housing. The switch cannot be activated without both of these push and slide movements. This can prevent accidental activation of the switch.
The arrangement comprises a micro switch 508. Part 509 of the second member (located inside the housing) that is fast with the plate 504 bears against an actuator of the micro switch 508 to activate and deactivate the switch, as described with reference to the previous implementation. As described previously, the first member 502 does not directly activate the micro switch 508. The first and second motions of the first member 502 indirectly activate the switch 508.
The plate 504 comprises a protrusion 505 which protrudes from the plane of the plate 504. The plate cannot move upwards in the housing without the first member 502 being first pushed in to release the protrusion 505 from the stop 506. In this example, the stop 506 is part of the housing 501. The first member 502 is fast with the plate 504. Thus pushing the first member inwards, followed by sliding it upwards, causes the protrusion to be released from the stop and the plate can then move longitudinally in the housing. When the protrusion is against the stop, the second member 503 is in a first, deactivated configuration. Releasing the protrusion from the stop by performing the second motion allows the first member to then move from a second configuration to a third configuration of the first member (i.e. allows the second motion of the first member to be performed).
The protrusion can then slide along the housing until it reaches a detent 507 which retains the protrusion 505 to prevent further upward movement of the plate 504. This retains the second member 503 in a second, activated configuration. When the protrusion is in the detent, the second member 503 may protrude from the housing in its second configuration more than it did in its first configuration. This may allow a user to easily access the second member to deactivate the switch. When the user performs a single first motion on the second member 503, which in this example comprises translating the member 503 by pushing it downwards, the protrusion 505 moves out of the detent 507, and can slide along the interior of the housing until it reaches the stop 506. The protrusion 505 is able to slide along a cam portion on the interior of the housing before passing a lip at an edge of the housing. At this point, the first and second members have been returned to their respective first configurations and the switch is deactivated.
In some examples, the plate may be rigid. In other examples, the plate may not be rigid and may be resiliently deformable. For example, the lower part of the plate may flex to get past the stop 506 and to move into the detent 507 and so only the lower part of the plate may move laterally in response to the first motion of the first member 502.
A resilient element 510 is configured to bias the plate 504 such that motion to either activate or deactivate the switch is resisted. The resilient element may be configured to bias the plate 504 in the activated position (once the second motion of the first member has been performed) and/or the deactivated position (before the first motion of the first member has been performed). In this example, the resilient element 510 is a spring. The resilient element urges the plate towards a wall of the housing. The resilient element biases the plate so as to resist the first motion of the first member. The spring biases the plate so that the protrusion 505 is retained in its initial position against the stop 506 and, when the first and second motions are sequentially performed, retains the protrusion in the detent 507. A user can overcome the force of the resilient element to perform the first motion of the first member 502.
Since the resilient element biases the plate in one direction, and movement of the second member from its second configuration (where the switch is activated) to its first configuration (where the switch is deactivated) occurs in a different direction, the resilient element does not directly oppose movement of the second member so as to deactivate the switch. Thus, the resilient element can resist activation of the switch without acting against movement to deactivate the switch. This arrangement provides a switch that remains easier to turn off, aiding safe operation of the switch.
In the examples described herein, the use of the resilient elements in the mechanism mean that the parts of the mechanism are urged towards respective positions irrespective of gravity. That is, where a tool is at an angle, for example on its side or upside down (which may occur during transport or when the tool is not being used), the mechanism still requires a two-stage activation and cannot be activated as a result of the first member being moved by a combination of gravity and an accidental motion.
The manually operable members may comprise visual indicia. The first manually operable member may comprise a visual indicator to indicate to the user that the first manually operable member is to be used to activate the powered device. For example, the first manually operable member may be coloured green, may display the word ‘ON’ or a line symbol. The second manually operable member may comprise a visual indicator to indicate to the user that the second manually operable member is to be used to deactivate the powered device. For example, the first manually operable member may be coloured red, may display the word ‘OFF’ or a circle symbol.
The first manually operable member may be formed from a green material. In this way, even when the mechanism is worn, the colour green will still be visible (compared, for example, to a surface coating or label that might wear away or peel off). Thus, maintenance of the visual indicator is ensured. Similarly, the second manually operable member may be formed from a red material. The red colour will still be visible to a user even when the mechanism is worn, providing the visual indication to the user.
The switch may be used in any powered device, such as a power tool or a piece of gardening equipment, such as a lawnmower.
The switch mechanism is particularly advantageous when used as part of a tool with heavy or sharp moving parts. The two-stage activation mechanism can prevent accidental activation of the device, which could result in injury of a user. Using a single motion to turn the powered device off also allows the device to be deactivated quickly when desired.
The powered device may be a battery-operated device or a mains-operated device.
For example, the switch may be used as part of a compacting power tool as described with reference to
The applicant hereby discloses in isolation each individual feature described herein and any combination of two or more such features, to the extent that such features or combinations are capable of being carried out based on the present specification as a whole in the light of the common general knowledge of a person skilled in the art, irrespective of whether such features or combinations of features solve any problems disclosed herein. In view of the foregoing description it will be evident to a person skilled in the art that various modifications may be made within the scope of the invention.
| Number | Date | Country | Kind |
|---|---|---|---|
| 23192793.0 | Aug 2023 | EP | regional |
