CN118061137A

CN118061137A - Hand-held electric tool

Info

Publication number: CN118061137A
Application number: CN202211481667.9A
Authority: CN
Inventors: 沈恒; 蔡德胜; S·西坎德尔; H·沃尔特
Original assignee: Hilti AG
Current assignee: Hilti AG
Priority date: 2022-11-24
Filing date: 2022-11-24
Publication date: 2024-05-24
Also published as: WO2024110247A1

Abstract

A hand held power tool comprising a main housing for a drive motor, a generally D-shaped handle extending from a lower or rear portion of the main housing, the D-shaped handle including a grip portion for a user to hold, and an auxiliary support portion extending substantially along a handle axis (a) on a front side of the grip portion, a base of the D-shaped handle having a base for mounting a battery pack; the auxiliary support is provided with a fall buffering structure, and the auxiliary support can be compressively deformed along the axis (A) of the handle. Thus, when the hand-held electric tool falls or is impacted accidentally, the impact force suffered by the electric tool can be buffered, and the risk of local damage or damage to the circuit board caused by deformation of the grip part of the handle is avoided.

Description

Hand-held electric tool

Technical Field

The present invention relates to a power tool, and more particularly, to a rechargeable hand-held power tool.

Background

The hand-held electric tool is the most commonly used electric tool, and the typical structure of the hand-held electric tool is a main body shell provided with a driving motor and a transmission mechanism, a handle formed by involutive half-handle shells extends out of the lower part of the main body shell, and a battery package inserting structure is arranged at the bottom of the handle. For some high power heavy duty power tools, the handle may be formed in a D-shape to more firmly support the body housing while ensuring gravity balance. Typically, the D-handle generally includes a grip portion for the user's hand to hold, and an auxiliary support portion located on the front side of the grip portion. One end of the auxiliary supporting portion is connected to the front end portion of the housing main body, and the other end is connected to the mounting portion of the battery pack, so that the electric tool has good operability and provides sufficient strength to the main body housing through the auxiliary supporting portion.

Structural stability is an important feature of power tools. In a hand-held power tool, an operator may inadvertently drop the power tool to the ground or the like. To detect the strength of a power tool, manufacturers often perform "drop tests" on the tool. So-called drop tests, i.e. the dropping of a power tool from a certain height, then detect if the tool breaks or otherwise fails. The results of these drop tests are then used to quantify the structural stability of the power tool. For many power tools, the handle of the tool is a point of failure. This is because the diameter of the handle is typically smaller to better fit the ergonomics of the user's hand, but a battery pack of great volume and weight is typically mounted to the bottom of the handle. Thus, such handles, which provide ergonomic benefits, tend to sacrifice structural stability of the handle base of the power tool.

In particular, for a power tool with a D-shaped handle, the auxiliary support portion of the D-shaped handle increases the strength of the main body housing, but for the grip portion, particularly the base portion of the grip portion for connection to the battery pack, becomes a weak point in the drop test, causing deformation or breakage of this portion. Also, since the battery pack is connected to the bottom of the handle, an electronic connection is often included inside the grip portion, for example, the battery is connected to the motor and the circuit board of the trigger, even with the risk of the electronic connection being damaged.

Disclosure of Invention

The technical problem to be solved by the invention is to provide a handheld electric tool, which can buffer the impact force applied to the electric tool when the electric tool falls on the ground or is subjected to accidental impact, so as to avoid the risk of local damage or damage to an electronic connecting piece caused by deformation of a shell or a handle.

In order to solve the technical problems, the technical scheme of the invention is as follows:

A hand-held power tool comprising a main housing for receiving a drive motor, a generally D-shaped handle extending from a lower portion of the main housing, the D-shaped handle including a grip portion for a user to hold and an auxiliary support portion extending substantially along a handle axis (a) on a front side of the grip portion, a base of the D-shaped handle having a base for mounting a battery pack; the auxiliary support is provided with a fall buffering structure so that the auxiliary support can be compressively deformed along the handle axis (a). Thus, when the electric tool falls, the auxiliary supporting part is compressed and deformed to absorb impact energy, so that the impact force born by the base part of the D-shaped handle is relieved, and the risk of damage to the electric tool is reduced.

The auxiliary supporting portion comprises a first portion adjacent to the main shell and a second portion adjacent to the base, and the fall buffering mechanism is clamped between the first portion and the second portion. The auxiliary supporting part is divided into an upper part and a lower part along the direction of the axis (A) of the handle by the falling buffer mechanism, when the electric tool falls, the main shell or the battery pack is impacted, and the falling buffer mechanism can deform when being stressed so that the first part and the second part of the auxiliary supporting part relatively move, thereby buffering the impact force suffered by the electric tool.

According to one embodiment of the present invention, the fall buffering mechanism includes an elastic body formed of a material having rubber elasticity. For example, an elastic body formed by rubber materials is a drop buffer mechanism which has low cost, simple structure and convenient assembly.

The elastic body comprises a main body extending along a handle axis (A), and a first clamping part and a second clamping part which extend outwards from the main body along the handle axis (A), wherein the first clamping part is clamped with the first part, and the second clamping part is clamped with the second part. The first clamping part and the second clamping part are respectively clamped in the first part and the second part, so that the elastic body is relatively fixed relative to the auxiliary supporting part, and the auxiliary supporting effect of the auxiliary supporting part is not influenced when the electric tool is not impacted.

The body of the elastomer is continuous in section in a direction perpendicular to the handle axis (a) and has a profile having substantially the same shape as the auxiliary support in a direction perpendicular to the handle axis (a). The elastomer body sandwiched between the first and second portions has the same shape as the cross-section of the first and second portions so that the auxiliary support remains integral from the outside, and the solid elastomer can provide similar support strength as the auxiliary support formed of other materials, such as plastic.

The length of the body of the elastomer in the direction of the handle axis (a) is 3% -25% of the length of the auxiliary support. When the length of the elastic body is too large, the strength of the auxiliary supporting portion is affected, and when it is too small, a good cushioning effect cannot be obtained.

According to another embodiment of the present invention, the fall buffering mechanism includes an elastic body formed of a material having rubber elasticity and a core shaft formed of a rigid material, the elastic body being wound around the core shaft and being relatively movable along the core shaft. The mandrel formed of rigid material is used to connect the elastomer and the auxiliary support, ensuring that the function of the auxiliary support is not impaired by the presence of the cushioning structure.

The two ends of the mandrel are respectively clamped in the first part and the second part, and the elastic body is clamped between the first part and the second part. In this way, the fall buffering arrangement is mounted on the auxiliary support in a simple and reliable manner.

The falling buffer mechanism is arranged on one side, close to the base, of the auxiliary supporting part. In the drop test, the point most prone to fracture is the base of the gripping part, and the drop buffer mechanism is arranged close to the base, so that the impact force is buffered better.

The hand-held power tool is an impact wrench or an impact drill. The D-shaped handle is often applied to high-power heavy impact wrenches and impact drills, the main body part of the impact wrenches or the impact drills is often heavier, an auxiliary supporting part is required to provide additional support for the main shell, and the impact force of the tool is larger when the tool falls due to heavier weight, so that the falling buffer mechanism can effectively prevent the electric tool from being damaged when falling.

Drawings

The embodiments will be better understood from the following detailed description when read with the accompanying drawings. It is emphasized that the various features are not necessarily drawn to scale. In fact, the dimensions may be arbitrarily increased or decreased for clarity of discussion. In the drawings, like reference numerals refer to like elements.

FIG. 1 illustrates an overall schematic of a hand-held power tool according to one embodiment of the present invention;

FIG. 2 is a schematic cross-sectional view of the hand-held power tool of FIG. 1;

FIG. 3 is a partial schematic view of the auxiliary support portion of the hand-held power tool of FIG. 1;

Fig. 4 is a partial schematic view of an auxiliary support portion of a hand-held power tool according to another embodiment of the present invention.

Detailed Description

Hereinafter, a hand-held power tool according to an embodiment of the present invention will be described with reference to fig. 1 to 4. The expressions "front", "rear", "above", "below", "left" and "right" in the present invention are used throughout the specification to define various parts of the power tool when disposed in the orientation in which it is intended to be used.

Fig. 1 shows a schematic view of a rechargeable power drill 1 of the present invention, which is an example of a power tool. Here, the hammer drill 1 is only one example of a hand-held power tool. The D-shaped handle is often applied to high-power heavy impact wrenches and impact drills, the main body part of the impact wrenches or the impact drills is often heavier, an auxiliary supporting part is required to provide additional support for the main shell, and the impact force of the tool is larger when the tool falls due to heavier weight, so that the falling buffer mechanism can effectively prevent the tool from being damaged when falling. The hand-held power tool of the present invention includes, but is not limited to, the impact drill described in this embodiment, and other hand-held power tools with a D-shaped handle are within the scope of the present invention.

The power tool 1 has a main housing 2 and a handle 3 extending from a lower portion of the main housing 2 in a substantially D-shape. The main casing 2 is formed with a central axis D in the front-rear direction. Inside the main casing 2, a motor 4, a transmission mechanism 5, and a working unit 6 are provided. The main housing 2 and the D-shaped handle 3 are made of plastic or resin. Preferably, the main housing 2 and the D-shaped handle 3 are divided into left and right involutable half-shells, and then assembled together.

The D-shaped handle 3 comprises a grip portion 7 for the user to hold, and an auxiliary support portion 8 at the front side of the grip portion. For example, the grip portion 7 is formed downward from the rear end of the main casing to form the rear side of the D-shaped handle 3. A trigger 9 protruding forward is provided at the upper end of the grip portion 7. Preferably, the grip portion 7 is located slightly behind the middle of the main casing 2. More preferably, the axis B through the grip portion passes through the center of gravity of the power tool. Thus, the electric impact tool of the present invention has good operability while achieving overall gravity balance.

The upper end of the auxiliary support portion 8 extends in a curved shape to the main casing 2 in front of the main casing 2 (for example, the gear case casing of the hammer drill of the present embodiment). The auxiliary support portion 8 is formed to extend downward from the curved upper end to form the front side of the D-shaped handle 3. The main body portion of the auxiliary support 8 defines a handle axis a extending through the auxiliary support. The handle axis a is substantially parallel to the axis B through the grip or at an angle to the axis B through the grip, for example not exceeding 30 degrees. The auxiliary support portion 8 has a smaller left-right width than the grip portion 7.

The lower end of the grip portion 7 and the lower end of the auxiliary support portion 8 are connected to form a base 11, whereby the handle 3 is formed in a substantially D-shaped ring. The battery pack mounting part 12 is fixedly connected to the base 11, and a battery pack (not shown) as a power source is detachably mounted to the battery pack mounting part 12, and a circuit board is mounted inside the base 11. The auxiliary support portion 8 extends between the bottom surface of the front end of the main housing 2 and the base 11 of the D-shaped handle. Preferably, a receiving space or a locking structure is formed in the auxiliary supporting part for installing the fall buffering mechanism of the present invention, which will be described in further detail below.

The electric tool of the invention, because the auxiliary supporting part 8 of the D-shaped handle 3 provides additional support for the main shell 2, the strength of the main shell is enhanced, and therefore, the weakest part or the most easily damaged part of the electric tool 1 is the part of the holding part 2 adjacent to the base 11 when the electric tool falls down or is impacted accidentally during the falling test or the use process. This is because the grip portion 2 cannot be too thick for ease of operation and ergonomics, and the weight of the tool body and the battery pack increases with the power demand, so that the impact energy received by the grip portion 7 and/or the auxiliary support portion 8 is concentrated in the portion adjacent to the base 11 during the fall, whether the tool body or the battery pack first contacts the ground. In addition, the axis of the holding part penetrates through the gravity center of the electric tool, so that the holding part is obviously subjected to larger impact force when falling. There have been many technical solutions in the prior art that a buffer or shock absorbing structure is added to the grip portion, but since the inside of the grip portion is required to arrange wires connecting the circuit board and the motor and the switch, and a ventilation structure is required to prevent the electronic components from overheating, the space and structure for installing the drop buffer or shock absorbing structure are very limited.

The falling buffer structure is arranged on the auxiliary supporting part 8, so that when the electric tool falls, the auxiliary supporting part 8 can be compressively deformed along the axis (A) of the handle, thereby relieving the impact force suffered by the base 11 of the D-shaped handle and/or the battery pack mounting part 12 and reducing the damage risk of the electric tool.

Referring to fig. 1 and 2, the auxiliary support 8 comprises a first portion 13 adjacent to the main casing 2 and a second portion 14 adjacent to the base 11. The fall buffering mechanism 10 is sandwiched between the first portion 13 and the second portion 14. That is, the auxiliary support 8 is discontinuous in the direction of the handle axis a, and the separated first and second portions 13 and 14 are connected by the fall buffering mechanism 10. The auxiliary supporting part 8 is divided into an upper part and a lower part along the direction of the axis (A) of the handle by the falling buffer mechanism 10, when the electric tool falls, the main body shell or the battery pack is impacted, and the falling buffer mechanism can deform when being stressed so that the first part and the second part of the auxiliary supporting part relatively move, thereby buffering the impact force suffered by the electric tool.

Preferably, the fall buffer mechanism 10 is disposed on the auxiliary supporting portion 8 on a side closer to the base 11. That is, the length of the first portion 13 is greater than that of the second portion 14, and the most easily broken point is the base of the grip portion in the drop test, and the drop buffer mechanism is disposed near the side of the base 11, so as to have a better impact buffering effect.

According to one embodiment of the present invention, the fall buffering mechanism 10 includes an elastic body formed of a material having rubber elasticity. As mentioned above, the fall buffering or damping structure has been widely used for the grip portion or the main handle, and the fall buffering structure 10 mounted on the auxiliary supporting portion 8 of the present invention is expected to achieve buffering impact in a simple structure and convenient installation. Therefore, in the present invention, the fall buffering structure 10 is an elastic body made of, for example, rubber, and has advantages of low cost, simple structure and convenient assembly.

The elastic body comprises a main body 15 extending along a handle axis (A), and a first clamping part 16 and a second clamping part 17 respectively extending outwards from the main body along the handle axis (A), wherein the first clamping part 16 is clamped in a storage space or a corresponding clamping structure formed in the first part 13, and the second clamping part 17 is clamped in the second part storage space or the corresponding clamping structure. The first clamping part 16 and the second clamping part 17 are respectively clamped to the first part 13 and the second part 14, so that the elastic body is relatively fixed relative to the auxiliary supporting part, and the auxiliary supporting effect of the auxiliary supporting part is not affected when the electric tool is not impacted. Referring to fig. 2 and 3, the first engaging portion 16 and the second engaging portion 17 may be ribs having a slightly smaller cross section than the elastomer body 15 and extending along the axis of the handle, and the first portion 13 and the second portion 14 respectively have a plurality of hooks formed therein, into which the ribs are engaged, so that the fall buffering mechanism 10 is fixedly connected to the auxiliary supporting portion 8. It will be appreciated that the first engaging portion 16 and/or the second engaging portion 17 may be other structures capable of fixedly connecting the elastic body to the first portion 13 and/or the second portion 14, for example, the first engaging portion 16 and/or the second engaging portion 17 may be a flange structure and the inside of the first portion 13 forms a groove for accommodating the flange, or the first engaging portion 16 and/or the second engaging portion 17 are protrusions formed on the upper and lower end surfaces of the main body 15, and the first portion 13 and/or the second portion 14 respectively form concave holes for accommodating the protrusions on the end surfaces where the first portion and/or the second portion 13 contact with the main body. The first engaging portion 16 and the second engaging portion 17 may have different engaging structures.

Preferably, the body 15 of the elastomer is continuous in section in a direction perpendicular to the handle axis (a) and has a profile substantially identical to the shape of the auxiliary support in a direction perpendicular to the handle axis (a). Although the fall buffering mechanism 10 of the present invention is fixedly connected to the auxiliary supporting portion 8 by the engagement structure, the electric tool, particularly the impact tool, generates a large vibration during use, and the continuous solid elastomer body 15 not only can elastically deform to provide buffering when the electric tool falls, but also can play a role in damping to a certain extent during use of the electric tool. Vibrations generated during operation of the power tool include vibrations in both the direction of the handle axis a and vibrations in a direction perpendicular to the handle axis a. The cross-sectional profile of the body 15 of the elastomer in the direction perpendicular to the handle axis (a) has substantially the same shape as the auxiliary support in the direction perpendicular to the handle axis (a), and also dampens vibrations in the direction perpendicular to the handle axis (a).

More preferably, the length of the body 15 of the elastomer in the direction of the handle axis (a) is 3% -25% of the length of the auxiliary support. When the length of the elastic body is too large, the strength of the auxiliary supporting portion is affected, and when it is too small, a good cushioning effect cannot be obtained. Of course, the length ratio of the body of the elastomer relative to the auxiliary support is related to many factors, such as the thickness of the auxiliary support, the material of the elastomer already, etc. For embodiments of rubber-formed elastomers, the length ratio should not be too great, which would otherwise affect the strength of the auxiliary support.

According to another embodiment of the present invention, referring to fig. 4, the fall buffering mechanism 10 includes an elastic body 18 formed of a material having rubber elasticity and a core shaft 19 formed of a rigid material, and the elastic body 18 is wound around the core shaft 19 and is relatively movable along the core shaft 19. Unlike the previous embodiment, the fall arrest mechanism 10 further comprises a rigid mandrel 19 formed of a rigid material for connecting the elastomer to the auxiliary support, ensuring that the function of the auxiliary support is not impaired by the presence of the arrest structure, while the elastomer 15 continues to deform during a fall so that the auxiliary support can be compressively deformed along the handle axis (a) to arrest the impact energy experienced during a fall.

The two ends of the mandrel 19 are respectively clamped inside the first portion 13 and the second portion 14, and the elastic body is clamped between the first portion and the second portion. In this way, the fall buffering arrangement is mounted on the auxiliary support in a simple and reliable manner. The snap-fit engagement of the spindle 19 with the first and second portions 13, 14 may also be achieved in a number of ways, such as a ring groove fit, etc. The shape of the mandrel 19 is not limited to a cylindrical shape, and an appropriate shape may be selected according to the structure of the auxiliary support portion, as long as the mandrel 19 is ensured to be fixed with respect to the auxiliary support portion 9.

The elastic body 18 is wrapped around the outer peripheral surface of the spindle 19, and at the same time, the elastic body 18 is relatively movable with respect to the spindle 19. The elastic body 18 is clamped between the first portion 13 and the second portion 14, so that when the power tool is dropped, the first portion 13 or the second portion 14 is forced to compress the elastic body 18, so that the first portion 13 and the second portion 14 are relatively close together, and energy generated by the impact is buffered.

As previously mentioned, although in the description exemplary embodiments of the invention have been described with reference to the accompanying drawings, the invention is not limited to the above-described specific embodiments, but many other embodiments are possible, the scope of which should be defined by the claims and their equivalents.

Claims

1. A hand-held power tool comprising a main housing for receiving a drive motor, a generally D-shaped handle extending from a lower portion of the main housing, the D-shaped handle including a grip portion for a user to hold and an auxiliary support portion extending substantially along a handle axis (a) on a front side of the grip portion, a base of the D-shaped handle having a base for mounting a battery pack; the method is characterized in that: the auxiliary support is provided with a fall buffering structure, and the auxiliary support can be compressively deformed along the axis (A) of the handle.

2. The hand-held power tool of claim 1, wherein the auxiliary support includes a first portion adjacent the main housing and a second portion adjacent the base, the fall buffering mechanism being sandwiched between the first and second portions.

3. The hand-held power tool of claim 2, wherein the fall buffering mechanism comprises an elastomer formed of a material having rubber elasticity.

4. A hand-held power tool according to claim 3, wherein the elastomer comprises a body extending along a handle axis (a) and first and second engagement portions extending outwardly from the body along the handle axis (a), respectively, the first engagement portion engaging the first portion and the second engagement portion engaging the second portion.

5. A hand-held power tool according to claim 4, wherein the body of the elastomer is continuous in cross-section in a direction perpendicular to the handle axis (a) and has a profile substantially identical to the shape of the auxiliary support in a direction perpendicular to the handle axis (a).

6. The hand-held power tool according to claim 5, wherein the length of the body of the elastomer in the direction of the handle axis (a) is no more than 3% -25% of the length of the auxiliary support.

7. The hand held power tool of claim 2, wherein the fall buffering mechanism includes an elastic body formed of a material having rubber elasticity and a stopper member formed of a rigid material, the elastic body surrounding the stopper member and being relatively movable along the stopper member.

8. The hand-held power tool of claim 7, wherein the two ends of the spindle are respectively clamped inside the first and second portions, and the elastic body is clamped between the first and second portions.

9. A fall buffering mechanism according to any one of claims 2 to 7, wherein the fall buffering mechanism is provided on a side of the auxiliary support portion near the base.

10. The power tool of any one of claims 1-9, being an impact wrench or an impact drill.