WO2020147002A1

WO2020147002A1 - A power tool with safety linkage mechanism

Info

Publication number: WO2020147002A1
Application number: PCT/CN2019/071758
Authority: WO
Inventors: Yan Jun Zhang; Yong Min LI; Jun Sheng CAI; Fu LIU
Original assignee: Tti (Macao Commercial Offshore) Limited
Priority date: 2019-01-15
Filing date: 2019-01-15
Publication date: 2020-07-23
Also published as: EP3912204A4; EP3912204A1; CN216085128U

Abstract

The present invention relates to a power tool and a power tool kit. The power tool comprises a battery receptacle defining a battery receiving space, the battery receptacle arranged to be removably coupled with a battery pack; an actuator moveable between ON and OFF positions to selectively operate a drive means of the power tool for driving a tool element; and a linkage mechanism operably connected with the actuator, wherein the linkage mechanism comprises a first linkage member being movable substantially linearly along a movement axis between a first position that prevents the battery pack to couple with the battery receptacle and a second position that allows the battery pack to couple with the battery receptacle. By utilising a mechanical linkage mechanism, the present invention provides a more reliable and cheaper mechanism to ensure the safety of users and prevent harm due to failure of any electronic mechanism, such as PCB board failure.

Description

A POWER TOOL WITH SAFETY LINKAGE MECHANISM

FIELD OF INVENTION

This invention relates to power tools and particularly, although not exclusively, to power tools with a safety linkage mechanism.

BACKGROUND OF INVENTION

A power tool, particularly a cordless DC power tool, typical requires connection with a battery pack to supply energy to the power tool. In situations where the user needs to remove the battery pack for storage or when the battery pack ran out of power during operation, the switch of the power tool is at the ON position and the user may carelessly forget to turn the switch off. When the user inserts a battery pack to the power tool when the switch is still at the ON position, the power tool will be powered up almost instantly and may cause harm to the user since the user is not prepared.

One existing way to prevent this potential danger is by adding a PCB control system in the power tool, such that if the user inserts the battery pack to the power tool when the switch is at the ON position, the power tool would not be functional. The user would have to turn the switch back to OFF position and then insert the battery pack again. However, malfunction of the PCB control system still sometimes happen, and such control system is expensive thus increasing the cost of the power tool.

Therefore, it is desirable to prevent the above identified danger through a more reliable and cheaper mechanism to ensure users’safety.

SUMMARY OF INVENTION

In the light of the foregoing background, it is an object to address the above needs, to overcome or substantially ameliorate the above disadvantages or, more generally, to provide a power tool with a safety linkage mechanism.

The above object is met by the combination of features of the main claims; the dependent claims disclose further advantageous embodiments of the invention.

One skilled in the art will derive from the following description other objects of the invention. Therefore, the foregoing statements of object are not exhaustive and serve merely to illustrate some of the many objects of the present invention.

Accordingly, the present invention, in one aspect is a power tool comprises a battery receptacle defining a battery receiving space, the battery receptacle is arranged to be removably coupled with a battery pack; an actuator movable between ON and OFF positions to selectively operate a drive means of the power tool for driving a tool element; and a linkage mechanism operably connected with the actuator, wherein the linkage mechanism comprises a first linkage member being movable substantially linearly along a movement axis between a first position that prevents the battery pack to couple with the battery receptacle and a second position that allows the battery pack to couple with the battery receptacle.

Preferably, the first linkage member is being moved to the first position when the actuator is being actuated to the ON position, and the first linkage member is being moved to the second position when the actuator is being actuated to the OFF position.

More preferably, at the first position the first linkage member extends at least partly into the battery receiving space and wherein at the second position the first linkage member does not extend into the battery receiving space.

Preferably, the battery receptacle is arranged to receive the battery pack along an axis different from the movement axis.

More preferably, the battery receptacle is arranged to slidingly receive the battery pack.

In one preferred embodiment, the first linkage member comprises a rod that elongates along the movement axis; a stopper; and a spring arranged between the rod and the stopper, where the spring is covered by a bush.

Preferably, upon the actuator is being actuated from the OFF position to the ON position while the battery pack is coupled to the battery receptacle, the spring is compressed under a resistive force from the battery pack such that the first linkage member does not extend into the battery receiving space, wherein upon the battery pack is being removed, the spring recoils such that at least part of the stopper extends into the battery receiving space.

More preferably, the linkage mechanism further comprises a second linkage member operably connected with the actuator and a connection member operably connected with the first linkage member and the second linkage member to facilitate movement of the first linkage member in response to movement of the second linkage member.

Preferably, the first linkage member elongates substantially along the movement axis and the second linkage member elongates substantially parallel to but is offset from the movement axis.

Most preferably, the movement of the first linkage member is opposite in direction to the movement of the second linkage member when the actuator is being actuated.

According to a variation of the preferred embodiments, the connection member is slidable along a sliding axis different from the movement axis.

Preferably, the connection member is only slidable along the sliding axis.

In one embodiment, the connection member includes a first ramp surface and a second ramp surface; the first linkage member includes a first corresponding ramp surface for slidably engaging with the first ramp surface; and the second linkage member includes a second corresponding ramp surface for slidably engaging with the second ramp surface.

Most preferably, the first ramp surface is a planar surface extending in a first plane, the second ramp surface is a planar surface extending in a second plane, where the first plane is not parallel to the second plane.

Preferably, the first plane and the second plane are both non-parallel to the movement axis.

According to another variation of the preferred embodiments, the connection member is rotatable relative to the first linkage member or the second linkable member.

Preferably, the connection member is rotatable about a rotation axis substantially perpendicular to the movement axis.

In another embodiment, the connection member includes a rotatable pinion gear with teeth, where the first linkage member includes a first rack for engaging with the teeth of the pinion gear and the second linkage member includes a second rack for engaging with the teeth of the pinion gear.

Preferably, the first linkage member and the second linkage member extend substantially parallel to each other.

In another embodiment, the connection member includes a plate pivotable about a pivot, the plate has a first opening and a second opening arranged at opposite sides of the plate, where the first linkage member is arranged to be coupled with the first opening through a first fastener and the second linkage member is arranged to be coupled with the second opening through a second fastener.

Preferably, the first fastener is movable within the first opening, and the second fastener is movable within the second opening.

Additionally, the power tool further comprises a switch for controlling activation of the drive means, wherein the actuator is operable by the user to selectively turn on and off the switch when the battery receptacle is coupled with the battery pack.

In one specific implementation, the power tool is a cordless DC-only power tool.

More specifically, the power tool is a grinder, for example, an angle grinder.

In another aspect, the present invention is a power tool kit comprises the power tool and a rechargeable battery pack arranged to be removably coupled with the battery receptacle of the power tool.

Other aspects of the invention will become apparent by consideration of the detailed description and accompanying drawings.

The present invention therefore provides various configurations for a mechanical line-lock-out system. By utilising a mechanical linkage mechanism connected to the ON/OFF actuator, the present invention provides a more absolute and cheaper mechanism to ensure the safety of users and prevent harm due to failure of any electronic mechanism, such as PCB board failure.

BRIEF DESCRIPTION OF FIGURES

The foregoing and further features of the present invention will now be described, by way of example, with reference to the accompanying drawings in which:

Figure 1A shows a cross-sectional view of a portion of a power tool having a linkage mechanism with the first linkage member at a second position according to one embodiment of the invention;

Figure 1B shows a close-up view of the first linkage member of Figure 1A;

Figure 2A shows a cross-sectional view of the portion of the power tool with the first linkage member at a first position;

Figure 2B shows a close-up view of the first linkage member of Figure 2A;

Figure 3A shows a cross-sectional view of the first linkage member of Figure 1A when coupled with a battery pack;

Figure 3B shows a close-up cross-sectional view of the first linkage member at the first position;

Figure 3C shows a close-up cross-sectional view of the first linkage member at the second position;

Figure 4 shows a perspective view of the connecting member of the power tool of Figure 1A;

Figure 5 shows a cross-sectional view of the portion of the power tool with the first linkage member being at the second position, the power tool having an alternative connecting member according to a second embodiment of the invention;

Figure 6 shows a cross-sectional view of the portion of the power tool with the first linkage member being at the first position and having the connecting member of Figure 5;

Figure 7 shows a cross-sectional view of the first linkage member of Figure 5;

Figure 8 shows a cross-sectional view of the portion of the power tool with the first linkage member being at the second position, the power tool having an alternative connecting member according to a third embodiment of the invention;

Figure 9 shows a cross-sectional view of the portion of the power tool with the first linkage member being at the first position and having the connecting member of Figure 8; and

Figure 10 shows a cross-sectional view of the first linkage member of Figure 8.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

Figure 1A shows a cross-sectional view of a portion of the power tool 100. Preferably, the power tool 100 is a cordless DC-only power tool, and although not shown completely in the figure, in this embodiment the power tool 100 is a grinder. The power tool 100 contains a linkage mechanism 102, and only the portion of the power tool 100 with the linkage mechanism 102 is shown in this illustrated embodiment. The power tool 100 contains a battery receptacle 120 which defines a battery receiving space. The battery receptacle 120 is arranged to be removably coupled with a battery pack (not shown) at the battery receiving space for receiving electrical energy. The battery pack is preferably a rechargeable battery pack. The power tool 100 further contains an actuator 104 movable between an ON position and an OFF position to selectively operate a drive means (not shown) of the power tool 100 for driving a tool element (not shown) . In this exemplary embodiment, the actuator 104 is a slidable actuator between the ON/OFF positions. The linkage mechanism 102 is operably connected with the actuator 104, where the linkage mechanism 102 contains a first linkage member 106 being movable substantially linearly along a movement axis A between a first position that prevents the battery pack from coupling with the battery receptacle 120 and a second position that allows the battery pack to couple with the battery receptacle 120. Preferably, the power tool 100 includes an opening 124 for the first linkage member 106 to extend into the battery receiving space.

In Figure 1A, the first linkage member 106 is at the second position. Figure 1B shows a close-up view of the first linkage member 106 at this second position, where the first linkage member 106 does not extend into the battery receiving space, such that the battery receptacle 120 is able to couple with the battery pack.

The battery receptacle 120 is arranged to receive the battery pack along an axis different from the movement axis A. In particular, the battery receptacle 120 is arranged to slidingly receive the battery pack along the axis B forming an acute angle with the movement axis A.

Figure 2A shows a cross-sectional view of the portion of the power tool 100, where the first linkage member 106 is at the first position. When the actuator 104 is being actuated to the OFF position, the first linkage member 106 is being moved to the second position as shown in Figures 1A and 1B, whereas when the actuator 104 of the power tool 100 is being actuated to the ON position, the first linkage member 106 is being moved to the first position. As shown in Figure 2B, when the first linkage member 106 is at the first position, the first linkage member 106 extends partly into the battery receiving space through the opening 124, thus preventing the battery pack from coupling with the battery receptacle 120.

The linkage mechanism 102 further contains a second linkage member 116 operably connected with the actuator 104, and a connection member 126 operably connected with the first linkage member 106 and the second linkage member 116 to facilitate a movement of the first linkage member 106 in response to a movement of the second linkage member 116 which results from the user actuating the actuator 104 in either direction.

Preferably, the first linkage member 106 elongates substantially along the movement axis A, and the second linkage member 116 elongates substantially parallel to but is offset from the movement axis A. In this embodiment, upon the actuator 104being actuated, the movement of the first linkage member 106 is opposite in direction to the movement of the second linkage member 116. To illustrate, when the user slides the actuator 104 to the left to the ON position, the second linkage member 116 which is connected with the actuator 104 also moves to the left, whereas in response to the left movement of the second linkage member 116, the first linkage member 106 moves to the right to extends into the battery receiving space. The power tool 100 further contains a switch 118 for controlling the activation of the drive means (not shown) , where the actuator 104 is operable by the user to selectively turn on and off the switch 118 when the battery receptacle 120 is coupled with the battery pack.

Referring now to Figures 3A to 3C. Figure 3A shows a cross-sectional view of the power tool 100 coupled with a battery pack 122 and Figures 3B and 3C show the cross-sectional views of the first linkage member 106. In this embodiment, the first linkage member 106 includes a rod 114 that elongates along the movement axis A, a stopper 108 and a spring 112 arranged between the rod 114 and the stopper 108. The spring 112 is covered by a bush 110. Figure 3B shows the spring 112 in a relaxed state, where the bush 110 completely covers up the connection part by the spring 112 between the rod 114 and the stopper 108, and Figure 3C shows the spring 112 in a compressed state.

In this embodiment, the user actuates the actuator 104 to the ON position, preferably by sliding it to the left direction. Upon the actuator 104being actuated from the OFF position to the ON position while the battery pack 122 is coupled to the battery receptacle 120, the spring 112 is compressed under a resistive force from the battery pack 122 such that the first linkage member 106 does not extend into the battery receiving space, wherein upon the battery pack 122 being removed, the spring 112 recoils such that at least part of the stopper 108 extends to the battery receiving space as shown in Figures 2A and 2B.

The connection member 126 in Figures 1A to 3C is slidable along a sliding axis C which is different from the movement axis A. In particular the connection member 126 is only slidable along the sliding axis C, and in this embodiment, the sliding axis C is perpendicular to the movement axis A.

Figure 4 shows a perspective view of the connection member 126 of the power tool 100 in Figures 1A to 3C. The connection member 126 has a substantially triangular shape and includes a first ramp surface 126a and a second ramp surface 126b. The first linkage member 106 includes a corresponding ramp surface 106a for slidably engaging with the first ramp surface 126a of the connection member 126, and the second linkage member 116 also includes a corresponding ramp surface 116a for slidably engaging with the second ramp surface 126b.

As illustrated in Figure 4, the first ramp surface 126a and the second ramp surface 126b of the connection member 126 are planar surfaces extending in the first plane and the second plane, where the first plane and the second plane are not parallel to each other, and are both non-parallel to the movement axis A. In one example, the first plane and the second plane form an acute angle such that the connection member 126 has a triangular cross-section. In Figure 3A, when the second linkage member 116 is being moved to the left, the corresponding ramp surface 116a causes the connection member 126 to move downwards, which in turns cause the first linkage member 106 to move to the right along the movement axis A.

In Figures 5 to 10, the

power tools

200, 300 are in general similar to the power tool 100 in Figures 1A to 3C (like components are labelled using like references) and only the major differences will be described here. In the

power tools

200, 300, their respective connection members are rotatable relative to the

first linkage member

206, 306 or the

second linkage member

216, 316. The connection members 226, 336 are each rotatable about a rotation axis D which is substantially perpendicular to the movement axis A.

Referring now to Figures 5 to 7, which show the connection member of the power tool 200 in a second embodiment. The connection member is a rotatable pinion gear 226 with teeth, the first linkage member 206 and the second linkage member 216 including a first rack 206a and a second rack 216a respectively for engaging with the teeth of the pinion gear 226. In this embodiment, the first linkage member 206 and the second linkage member 216 extend substantially parallel to each other.

Figure 6 shows the first linkage member 206 at the first position. When the actuator 204 thus the second linkage member 216 are actuated to the left direction, the movement causes the pinion gear 226 to rotate in an anti-clockwise direction. As the teeth of the pinion gear 226 is engaged with the first and

second linkage member

206, 216, the rotation of the pinion gear 226 in turn causes the first linkage member 206 to move to the right direction and extend into the battery receiving space. Figure 7 is similar to Figure 3A, except that the connection member is a rotatable pinion gear 226 instead of a slidable member 126.

Figures 8 to 10 show the connection member of the power tool 300 in a third embodiment. The connection member includes a plate 326 pivotable about a pivot, the plate 326 having a first opening 326a and a second opening 326b arranged at opposite sides of the plate 326. The first linkage member 306 is arranged to be coupled with the first opening 326a through a first fastener 336a and the second linkage member 316 is arranged to be coupled with the second opening 326b through a second fastener 336b. The first fastener 336a is movable within the first opening 326a, and the second fastener 336b is movable within the second opening 326b.

Figure 9 shows the first linkage member 306 at the first position. When the actuator 304 thus the second linkage member 316 are actuated to the left direction, the movement causes the plate 326 to rotate in an anti-clockwise direction. As the second linkage member 316 is fastened to one end of the plate 326 and the first linkage member 306 is fastened to the other end of the plate 326, the rotation of plate 326 causes the first linkage member 306 to move to the right direction and extend into the battery receiving space. Figure 10 is similar to Figure 7, except that the connection member is a pivotable plate 326 instead of a rotatable pinion gear 226.

While the invention has been illustrated and described in detail in the drawings and foregoing description, the same is to be considered as illustrative and not restrictive in character, it being understood that only exemplary embodiments have been shown and described and do not limit the scope of the invention in any manner. It can be appreciated that any of the features described herein may be used with any embodiment. The illustrative embodiments are not exclusive of each other or of other embodiments not recited herein. Accordingly, the invention also provides embodiments that comprise combinations of one or more of the illustrative embodiments described above. Modifications and variations of the invention as herein set forth can be made without departing from the spirit and scope thereof, and, therefore, only such limitations should be imposed as are indicated by the appended claims.

Although not shown in the figures, but in other embodiments, the

power tool

100, 200, 300 may be another type of tools or devices that comprises a battery receptacle for coupling with a battery, and a mechanical linkage mechanism for preventing the coupling when the switch is ON.Similarly, the actuator 104 can be a rotatable actuator rotatable between the ON/OFF positions to cause a linear movement of the second linkage member 116. According to embodiments illustrated above, the axis B along which the battery pack is being installed to the battery receptacle 120 forms an angle with the movement axis A, but in other embodiments, the axis B can be perpendicular to the movement axis A, or forms an oblique angle with the movement axis A.

The connection member 126 can have other cross-section profiles, such as trapezoidal or circular, where the first linkage member 106 and the second linkage member 116 have the corresponding surfaces to engage with the connection member 116. Similarly, the sliding axis C along which the connection member 226 moves can be oblique to the movement axis A that allows the translation of movement from the actuator 104 to the first linkage member 106.

From the illustrated embodiments above, the connection members 226, 336 are rotatable members having a pinion gear with teeth or a pivotable plate. In other embodiments, the connection members can be other rotatable members rotatable at an angle with the movement axis A. The

first linkage member

106, 206, 306 includes a rod, a stopper and a spring covered by a bush in the above description, but in other embodiments, the

first linkage member

106, 206, 306 can be a single rod movable linearly to and from the first and second positions, where the battery pack 122 has a corresponding opening for receiving the rod when a user actuates the rod to the first position while the battery pack 122 is coupled with the battery receptacle 120.

Terms such as “forward” , “rearward” , “in front of” , ” behind” , “highest” , “lowest” , “left” , “right” and similar terms as used herein are for the purpose of describing the invention in its normal in-use orientation and are not intended to limit the invention to any particular orientation.

Any reference to prior art contained herein is not to be taken as an admission that the information is common general knowledge, unless otherwise indicated.

Claims

A power tool, comprising:

a battery receptacle defining a battery receiving space, the battery receptacle arranged to be removably coupled with a battery pack;

an actuator movable between ON and OFF positions to selectively operate a drive means of the power tool for driving a tool element; and

a linkage mechanism operably connected with the actuator, wherein the linkage mechanism comprises a first linkage member being movable substantially linearly along a movement axis between a first position that prevents the battery pack to couple with the battery receptacle and a second position that allows the battery pack to couple with the battery receptacle.
The power tool of claim 1, wherein the first linkage member is being moved to the first position when the actuator is being actuated to the ON position, and the first linkage member is being moved to the second position when the actuator is being actuated to the OFF position.
The power tool of claim 1 or 2, wherein at the first position the first linkage member extends at least partly into the battery receiving space and wherein at the second position the first linkage member does not extend into the battery receiving space.
The power tool of any one of claims 1 to 3, wherein the battery receptacle is arranged to receive the battery pack along an axis different from the movement axis.
The power tool of claim 4, wherein the battery receptacle is arranged to slidingly receive the battery pack.
The power tool of any one of claim 1 to 5, wherein the first linkage member comprising:

a rod that elongates along the movement axis;

a stopper;

a bush connecting the rod and the stopper; and

a spring arranged inside the bush and between the rod and the stopper.
The power tool of claim 6, wherein upon the actuator is being actuated from the OFF position to the ON position while the battery pack is coupled to the battery receptacle, the spring is compressed under a resistive force from the battery pack such that the first linkage member does not extend into the battery receiving space, wherein upon the battery pack is being removed, the spring recoils such that at least part of the stopper extends into the battery receiving space.
The power tool of any one of claims 1 to 7, wherein the linkage mechanism further comprising:

a second linkage member operably connected with the actuator; and

a connection member operably connected with the first linkage member and the second linkage member to facilitate movement of the first linkage member in response to movement of the second linkage member.
The power tool of claim 8, wherein the first linkage member elongates substantially along the movement axis.
The power tool of claim 8 or 9, wherein the second linkage member elongates substantially parallel to but is offset from the movement axis.
The power tool of any one of claims 8 to 10, wherein the movement of the first linkage member is opposite in direction to the movement of the second linkage member when the actuator is being actuated.
The power tool of claim 11, wherein the connection member is slidable along a sliding axis different from the movement axis.
The power tool of claim 12, wherein the connection member is only slidable along the sliding axis.
The power tool of claim 12 or 13, wherein:

the connection member includes a first ramp surface and a second ramp surface;

the first linkage member includes a first corresponding ramp surface for slidably engaging with the first ramp surface; and

the second linkage member includes a second corresponding ramp surface for slidably engaging with the second ramp surface.
The power tool of claim 14, wherein the first ramp surface is a planar surface extending in a first plane, the second ramp surface is a planar surface extending in a second plane, and wherein the first plane is not parallel to the second plane.
The power tool of claim 15, wherein the first plane and the second plane are both non-parallel to the movement axis.
The power tool claim 11, wherein the connection member is rotatable relative to the first linkage member or the second linkage member.
The power tool of claim 17, wherein the connection member is rotatable about a rotation axis substantially perpendicular to the movement axis.
The power tool of claim 17 or 18, wherein:

the connection member comprises a rotatable pinion gear with teeth;

the first linkage member comprises a first rack for engaging with the teeth of the pinion gear; and

the second linkage member comprises a second rack for engaging with the teeth of the pinion gear.
The power tool of claim 19, wherein the first linkage member and the second linkage member extend substantially parallel to each other.
The power tool of claim 17 or 18, wherein:

the connection member comprises a plate pivotable about a pivot, the plate includes a first opening and a second opening arranged at opposite sides of the plate;

the first linkage member is arranged to be coupled with the first opening through a first fastener; and

the second linkage member is arranged to be coupled with the second opening through a second fastener.
The power tool of claim 21, wherein the first fastener is movable within the first opening, and the second fastener is movable within the second opening.
The power tool of any one of claims 1 to 22, further comprising:

a switch for controlling activation of the drive means;

wherein the actuator is operable by the user to selectively turn on and off the switch when the battery receptacle is coupled with the battery pack.
The power tool of any one of claims 1 to 23, wherein the power tool is a cordless DC-only power tool.
The power tool of any one of claims 1 to 24, wherein the power tool is a grinder.
A power tool kit comprising:

a power tool of any one of claims 1 to 24; and

a rechargeable battery pack arranged to be removably coupled with the battery receptacle of the power tool.