WO2011110187A1

WO2011110187A1 - Power tool with battery protector

Info

Publication number: WO2011110187A1
Application number: PCT/EP2010/001405
Authority: WO
Inventors: Oskar Bergquist; Johan BJÖRNLINGER; Pär MARTINSSON; Pär RACOV; Johan Svennung
Original assignee: Husqvarna Ab
Priority date: 2010-03-06
Filing date: 2010-03-06
Publication date: 2011-09-15
Also published as: WO2011110187A8

Abstract

The present invention relates to an electric power tool (100, 200, 300) which includes one or more working implements, an electric drive motor drivably connected to the working implements, and at least one battery (112, 212, 312) connected to the electric drive motor. The battery (112, 212, 312) includes at least one battery cell (126) encased in a cell housing (124). Further, the cell housing (124) is electrically and mechanically connected to the battery (112, 212, 312) at a connection interface of the the electric power tool (100, 200, 300). The electric power tool (100, 200, 300) is provided with at least one battery protector (132) extending from the electric power tool (100, 200, 300) proximate the connection interface, such that the battery protector (132) extends beyond a surface (122, 228) of the battery (112, 212, 312).

Description

POWER TOOL WITH BATTERY PROTECTOR

TECHNICAL FIELD

The present invention relates to an electric power tool. In particular, the present invention relates to an electric power tool which is powered by a battery.

BACKGROUND

Battery operated hand-held electric power tools such as, but not limited to, chainsaws, line trimmers, and hedge trimmers are well known in the art. Typically, a battery is detachably attached to an electric power tool by externally mounting the battery on the electric power tool or by inserting the battery partially into a battery housing of the electric power tool. Normally, the battery extends out of the battery housing to allow easy grasping and handling of the battery.

U.S. Pat. No. 4,084,123 issued on April 11, 1978 and assigned to Disston Inc., titled "Cordless electric devices having rechargeable battery pack(s)" describes a rechargeable battery pack which can be externally mounted on a portable cordless electric tool. The rechargeable battery pack includes specially designed AC prongs that can be used to connect the battery pack to the electric tool as well as for charging the battery directly from a standard AC power supply. Another U.S. Pat. No. 3,757,194 issued on September 04, 1973 and assigned to The Black and Decker Manufacturing Company, titled "cordless power tool having removable battery pack " describes a battery pack which can be externally mounted on a shrub or a hedge trimmer. The battery pack is detachable from the shrub or the hedge trimmer and includes an AC to DC converter for directly deriving power from a main power supply connection. In both of the aforementioned U.S. patents, the battery packs are externally mounted on the power tools and are susceptible to mechanical shocks. The battery packs can easily sustain damage in case the hand-held electric power tools fall on the ground or collide with any other surfaces during operation. U.S. Design Pat. No. 434,620 issued on December 05, 2000 and assigned to The Toro Company, titled "housing for a hedge trimmer " illustrates a battery housing for a hedge trimmer in which the battery is partially housed. However, a rear portion of the battery is exposed to accidental impacts and collisions. Further, in some cases, the battery is completely inserted into a battery housing. However, this results in an inconvenience during grasping and handling of the battery.

In light of the foregoing, there is a need for a hand-held electric power tool and battery combination that safeguards the battery against mechanical shocks, and also provides easy grasping and handing of the battery.

SUMMARY

In view of the above, it is an objective of the present invention to solve or at least reduce the problems discussed above. In particular, the objective is to provide an improved electric power tool, which is powered by a battery, such that the battery is protected against mechanical impacts, and the battery can be easily grasped and handled.

The objective is at least partially achieved according to a novel electric power tool described in claim 1. The electric power tool includes one or more working implements, an electric drive motor drivably connected to the working implements, and at least one battery connected to the electric drive motor for supplying it with electrical energy. The battery includes at least one battery cell encased in a cell housing. The cell housing is provided with electrical contacts and at least one mechanical mating surface to electrically and mechanically connect the battery at a connection interface of the electric power tool. Further, the electric power tool is provided with at least one battery protector which extends from the electric power tool proximate the connection interface. The battery protector extends beyond a surface of the battery such that the battery is protected at least partially against mechanical impacts from one or more sides.

According to claim 2, the battery protector encloses the battery on at least one side. According to claim 3, the battery protector encloses the battery on one or more of a front side, a rear side, a top side, and a bottom side.

According to claim 4, the battery protector is a single extending wall which protects the battery against accidental impacts from only one side. According to claim 5, the battery protector encloses the battery on at least four sides, thus safeguarding the battery against mechanical shocks from at least four sides.

According to claim 6, the battery protector includes a housing to enclose the battery, at least one of the walls extending beyond the surface of the battery. According to claim 7, the at least one extending wall of the housing may extend variably beyond the surface of the battery.

According to claim 8, the battery includes at least one handle to provide easy grasping and handling of the battery. Moreover, to further assist the handing, of the battery, according to claim 9 the battery includes an extending section such that the extending section extends beyond the housing of the electric power tool.

According to claim 10, the electric power tool may be one of a chain saw, a line trimmer, or a hedge trimmer.

BRIEF DESCRIPTION OF THE DRAWINGS

The invention will in the following be described in more detail with reference to the enclosed drawings, wherein:

FIG. 1 A illustrates a rear perspective view of an electric power tool, according to an embodiment of the present invention;

FIG. IB illustrates a front perspective view of an electric power tool, according to an embodiment of the present invention;

FIG. 1C illustrates a sectional view of the electric power tool, according to an embodiment of the present invention;

FIG. 2 illustrates a perspective view of a line trimmer, according to an embodiment of the invention; and

FIG. 3 illustrates a perspective view of a line trimmer, according to another embodiment of the invention.

DESCRIPTION OF EMBODIMENTS

The present invention will be described more fully hereinafter with reference to the accompanying drawings, in which example embodiments of the invention incorporating one or more aspects of the present invention are shown. This invention may, however, be embodied in many different forms and should not be construed as limited to the embodiments set forth herein; rather, these embodiments are provided so that this disclosure will be thorough and complete, and will fully convey the scope of the invention to those skilled in the art. For example, one or more aspects of the present invention can be utilized in other embodiments and even other types of devices. In the drawings, like numbers refer to like elements. FIGS. 1 A and IB illustrate two views of an example chain saw 100, according to an embodiment of the present invention. The chain saw 100 (hereinafter referred to as the "electric power tool 100") may be used in gardening or forestry applications. However, the present invention may also be used in any other battery powered equipment, for example, line trimmers, hedge trimmers, drills, reciprocating saws, rotary saws, power screw drivers, or other cutting or pruning tools without departing from the essence of the present invention. In addition, any suitable size, shape or type of elements or materials could be used. Further, as used herein, the terms "longitudinal direction" and "transverse direction" indicate a direction relative to the electric power tool 100. The term "longitudinal direction", without further specificity, is a reference to a direction parallel to a longitudinal axis L of the electric power tool 100. The term "transverse direction", without further specificity, is a reference to a direction perpendicular to the longitudinal axis L when viewed from the top i.e., substantially perpendicular to the plane of the paper in a side view. The terms "front side" and "rear side" of a part or portion of the electric power tool 100 may in general refer to sides of the part or portion that are substantially along the longitudinal axis L, the "front side" being further from a user than the "rear side" during an operation of the electric power tool 100. The terms "top side" and "bottom side" of any part or portion may in general refer to sides substantially perpendicular to the longitudinal axis L, the "top side" and the "bottom side" being at the top and the bottom of the part or portion respectively.

As shown in FIGS. 1 A and IB, in an embodiment of the present invention, the electric power tool 100 includes a tool body 102 with one or more supports 104 to retain one or more working implements (not shown in the FIGS. 1A and IB). In an embodiment of the present invention, the tool body 102 may include a front handle 106 and a rear handle 108. The rear handle 108 may include a grip portion 109 to aid in manual grasping of the electric power tool 100. At least one of the front handle 106 or the rear handle 108 may include vibration absorbing means, such as springs, rubber member, or the like. A guard 110 may be present to safeguard a user against stray particles during a cutting operation. In an embodiment of the present invention, the working implements may include a toothed chain supported on a guide bar. The guide bar may be attached to the one or more supports 104 via one or more fasteners. A drive sprocket and an idler sprocket may be present at a proximate end and a distal end of the guide bar respectively with respect to the tool body 102. In an embodiment of the present invention, the drive sprocket may be driven by an electric drive motor (not shown) via suitable transmission means for example but not limited to, one or more gears, belt drive, friction drive, or any combination of these. The transmission means may be utilized to selectively drive the drive sprocket at one or more speeds. The electric drive motor may be an electrically powered motor, such as but not limiting to, AC motor, DC motor, or the like. In an embodiment of the present invention, the speed and torque of the electric motor may be continuously or discretely varied by suitable control means. The control means may include one or more sensors to sense various parameters of the electric drive motor, for example, speed, torque etc. The sensed parameters may then be utilized to control the speed and/or torque of the electric drive motor. In an embodiment of the present invention, the electric drive motor is selectively supplied with electrical energy by a battery 112 depending on the activation or deactivation of an on/off switch 114. The rated power and other specifications of the electric drive motor and the battery 112 may be selected based on various parameters, for example, power requirements, operational durations, expected life, cost, weight, dimensions etc.

In an embodiment of the present invention, the battery 112 may be detachably attached to the tool body 102 of the electric power tool 100. However, in other embodiments of the present invention, the battery 112 may be fixedly attached to the electric power tool 100. In an embodiment of the present invention, the battery 112 may include at least one handle (not shown) to aid in grasping and handling of the battery.

FIG. 1C illustrates a sectional view of the electric power tool 100, according to an embodiment of the present invention. The battery 112 includes a cell housing 124 which may encase one or more battery cells 126. Though in the example embodiment, the battery cells 126 are shown to be stacked substantially parallel to each other in multiple columns, other configurations (e.g. staggered) may be envisioned without departing from the essence of the present invention. One or more battery cells 126 may also be placed adjacent to one another in the transverse direction of the electric power tool 100. The one or more battery cells 126 may be rechargeable Lithium-Ion or Nickel-Cadmium cells. Inner surfaces of the cell housing 124 may include electrical conductors to electrically connect poles of the one or more battery cells 126 to one or more electric contacts 128. The one or more electric contacts 128 may extend at least partially in the transverse direction. In an embodiment of the present invention, the one or more electric contacts 128 may engage electrically with one or more corresponding electrical contacts provided in the tool body 102 to form electrical connections. In an embodiment of the present invention, the electrical contacts 128 may also be utilized to charge the one or more battery cells 126 from an external power source. The battery 112 may also include at least one mechanical mating surface (not shown) to mechanically connect the battery 112 to the tool body 102 of the electric power tool 100. The mechanical mating surface may include suitable releasable mechanical connections, for example, but not limited to, snap-fit connections, mating recesses and grooves, connections with resilient members (e.g., springs), or a combination of any of these.

Further, as shown in FIGS. 1A and IB, the mechanical connections may be selectively locked or released without the use of tools. In other embodiments of the present invention, in case the battery 112 is fixedly attached to the electric power tool 100, the mechanical connections may require one or more tools to disassemble the battery 112 from the tool body 102 of the electric power tool 100. In an embodiment of the present invention, the battery 112 and the tool body 102 may be provided with a connection interface (not shown) which may include the electrical connections and the mechanical mating surface. The connection interface may extend in the transverse direction at one or more sides of the battery 112.

In an embodiment of the present invention, a battery protector 132 is provided such that it extends from the tool body 102 proximate the connection interface in the transverse direction. In an embodiment of the present, the battery protector 132 includes one or more extending walls 134 such that the battery protector 132 extends beyond the surface 122 of the battery 112. As shown in FIGS. 1A and IB, the battery protector 132 may have four extending walls 134 such that the extending walls 134 may enclose the battery 112 on four sides, namely a front side, a rear side, a top side, and a bottom side (all sides with respect to the battery 112). However, in other embodiments of the present invention, the extending walls 134 may enclose the battery 112 on one or more sides.

In an embodiment of the present invention, at least one of the extending walls 134 may extend variably along its length. In another embodiment of the present invention, the extending wall 134 at the front side of the battery 112 may extend the most whereas the extending wall 134 at the rear side of the battery 112 may extend the least. Further, the extending walls 134 at the top side and the bottom side may extend variably and connect the extending walls 134 at the front side and the rear side. The extending walls 134 may have one or different types of surfaces, for example but not limiting to, straight, arcuate, tapered, or the like. The nature of the surfaces may also vary along the length of at least one extending wall 134. In an embodiment of the present invention, one or more of the extending walls 134 may be separately manufactured and then attached to the tool body 102. In another embodiment of the present invention, the extending walls 134 may be manufactured as a single unit and then fixed to the tool body 102. In a still another embodiment of the present invention, the extending walls 134 may be manufactured as a part of the tool body 102.

In an embodiment of the present invention, the battery protector 132 may include a housing 136 into which the battery 112 is inserted. In another embodiment of the present invention, the extending wall 134 may form part of the housing 136. The housing 136 may have various configurations without departing from the essence of the present invention, for example, but not limited to, a one-piece configuration, a modular configuration with one or more shells, or the like. The housing 136 may also be detachably attached to the tool body 102 to aid in repair or maintenance. The housing 136 may be made of a suitable material, such as metal, plastic, or the like.

In various embodiments of the present invention, the battery protector 132 may at least partially enclose the battery 112. The battery protector 132 may permit the insertion of the battery 112 from the rear substantially parallel to the longitudinal direction. In an embodiment of the present invention, the battery protector 132 may include at least one extending wall 134 and an additional wall that at least partially enclose the battery 112 on a front side and a lateral side respectively, such that the lateral side is substantially parallel to and offset from the longitudinal axis L. Further, the extending wall 134 may extend from the longitudinal axis L of the electric power tool 100 such that it extends beyond at least one surface of the battery 112. The additional wall may extend the battery 112 substantially rearwards along the longitudinal direction. In an embodiment of the present invention, at least one of the extending wall 134 and the additional wall may extend the battery 112 in a direction perpendicular to both of the longitudinal direction and the transverse direction. In another embodiment of the present invention, an auxiliary wall may enclose the battery 112 on the lower side or upper side.

In an embodiment of the present invention, a single extending wall 134, which is placed at the rear side of the battery 112 along the longitudinal direction L, may act as the battery protector 132. However, in other embodiments of the present invention, the single extending wall 134 may be placed on any other side of the battery 112, such as the front side, bottom side, or the top side of the battery 112. The battery 112 may be inserted into the power tool 110 in a transverse direction.

FIG. 2 illustrates a line trimmer 200, according to an embodiment of the invention. The line trimmer 200 includes a main body 202, a shaft 204 and a cutting assembly (not shown). The main body 202 includes a rear handle 208 and a housing 210. A front handle 214 may also be provided on the shaft 204. A rechargeable battery 212 may be removably attached to the housing 210. In other embodiments of the present invention, the battery 212 may be fixedly attached to the housing 210. The cutting assembly may include an electric drive motor which drives one or more working implements. The electric drive motor may be electrically connected to the battery 212 via one or more conductors (not shown). The one or more working implements may include one or more cutting means, for example, but not limited to, filament cutters, cutter blades, or the like.

In an embodiment of the present invention, the housing 210 may include one or more extending walls 226 that enclose the battery 212 on one or more sides and extend beyond a surface 228 of the battery 212. As shown in FIG. 2, the extending walls 226 enclose, the battery on four sides. However, other configurations of the extending walls 226 are possible.

FIG. 3 illustrates a line trimmer 300, according to another embodiment of the invention. The line trimmer 300 includes a main body 302 and a rear handle 304. The main body 302 includes a housing 310 into which a battery 312 may be inserted in the transverse direction to be detachably attached to the main body 302. In other embodiments of the present invention, the battery 312 may be fixedly attached to the housing 310. In an embodiment of the present invention, the battery 312 may include an extending section 311 which may extend out of the housing 310, such that the extending section 311 may be used to grasp the battery 312. In an alternate embodiment of the present invention, the battery 312 may include at least one handle (not shown) to aid in the handling of the battery 312. As shown in FIG. 3, a single extending wall 326, which is placed at the front side of the battery 308, may act as the battery protector. The single extending wall 326 may extend further from the housing 310 than the battery 312. However, in other embodiments of the present invention, the single extending wall 326 may be placed on any other side of the battery 312, such as the front side, bottom side, or the top side of the battery 312. The extending wall 326 may be distinct from the housing 310 or may be integral with the housing 310.

The details of the line trimmers 200 and 300 shown in FIGS. 2 A, 2B and 3 are for illustrative purposes only and it may be evident to a person ordinarily skilled in the art that the line trimmer 200 and 300 may be of various configurations and shapes without deviating from the present invention.

In the drawings and specification, there have been disclosed preferred embodiments and examples of the invention and, although specific terms are employed, they are used in a generic and descriptive sense only and not for the purpose of limitation, the scope of the invention being set forth in the following claims.

Claims

1. An electric power tool (100, 200, 300) comprising:

one or more working implements;

an electric drive motor drivably connected to the working implements;

at least one battery (112, 212, 312) connected to the electric drive motor for supplying electrical energy, wherein the battery (112, 212, 312) comprises at least one battery cell (126) encased in a cell housing (124);

the cell housing (124) being provided with electrical contacts (128) and at least one mechanical mating surface to electrically and mechanically connect the battery (112, 212, 312) at a connection interface of the the electric power tool (100, 200, 300),

characterized in that,

the electric power tool (100, 200, 300) is provided with at least one battery protector (132) extending from the electric power tool (100, 200, 300) proximate the connection interface, wherein the battery protector (132) extends beyond a surface (122, 228) of the battery (112, 212, 312).

2. An electric power tool (100, 200, 300) according to claim 1, wherein the battery protector (132) encloses the battery (112, 212, 312) on at least one side.

3. An electric power tool (100, 200, 300) according to claim 2, wherein the at least one side is one of a front side, a rear side, a top side, or a bottom side.

4. An electric power tool (100, 200, 300) according to claim 1 , wherein the battery protector (132) is a single extending wall (134, 226, 326).

5. An electric power tool (100, 200, 300) according to claim 1, wherein the battery protector (132) encloses the battery (112, 212, 312) on at least four sides.

6. An electric power tool (100, 200, 300) according to claim 1, wherein the battery protector (132) comprises a housing (136, 210, 310) to enclose the battery (112, 212, 312), wherein at least one wall (134, 226, 326) of the housing (136, 210, 310) extends beyond the surface (122, 228) of the battery (112, 212, 312).

7. An electric power tool (100, 200, 300) according to claim 6, wherein the at least one wall (134, 226, 326) of the housing (136, 210, 310) may extend variably beyond the surface (122, 228) of the battery (112, 212, 312).

8. An electric power tool (100, 200, 300) according to any of the claims 1 to 7, wherein the battery (112, 212, 312) comprises at least one handle.

9. An electric power tool (100, 200, 300) according to any of the claims 1 to 8, wherein the battery (112, 212, 312) comprises at least one extending section (311), wherein the at least one extending section (311) extends beyond the housing (136, 210, 310) of the electric power tool (100, 200, 300).

10. An electric power tool (100, 200, 300) according to any one of the claims 1 to 9, wherein the eletric power tool (100, 200, 300) is one of a chain saw (100), a line trimmer (200, 300), or a hedge trimmer.