Hand-held power tool

Abstract

The invention relates to a hand-held power tool (1), in particular a rotary hammer or demolition hammer, comprising a housing (2), which preferably has multiple housing parts, an impact mechanism accommodated in the housing (2), an electric motor (3) accommodated in the housing (2) for driving the impact mechanism, and a handle part (4) movably mounted relative to the housing (2). The handle part (4) engages in a collar section (5) of the housing (2), which collar section surrounds the handle part (4) without contact, forming a defined ventilation gap (6) on at least three sides, preferably all around.

Description

[0001] 2025P00047EP Hilti Aktiengesellschaft

[0002] Principality of Liechtenstein

[0003] HAND TOOL MACHINE

[0004] DESCRIPTION

[0005] The invention relates to a hand-held power tool, in particular a drill or chisel hammer, with the features of the preamble of claim 1.

[0006] State of the art

[0007] Power tools, such as rotary hammers and demolition hammers, have an impact mechanism to generate a striking motion that acts on a tool, for example, a chisel. This striking motion causes the housing of the power tool, in which the impact mechanism is located, to vibrate. To prevent these vibrations from being transmitted to a handle attached to the housing, the handle is usually spring-mounted against the housing.

[0008] From EP 0 370 952 A1, for example, a rotary hammer or chisel is known with an impact mechanism, a housing surrounding the impact mechanism, and a handle connected to the housing and spring-supported on the housing in the direction of impact. To improve vibration characteristics, an additional mass is also spring-supported on the housing in the direction of impact. A circumferential gap between the housing and the handle, which varies in size depending on the degree of handle deflection, is sealed by a bellows. The bellows prevents dirt particles from penetrating the housing. At the same time, the bellows allows relative movement between the handle and the housing.

[0009] German patent DE 102006060652 A1 discloses another electric hand-held power tool with two housing parts movable relative to each other and spaced apart, between which a bellows is arranged. The bellows has end sections, each formed by a rigid plastic ring molded by injection molding. The plastic rings can be positively connected to the housing parts, preventing dirt particles from penetrating the housing.

[0010] During operation of a hand-held power tool, particularly a rotary hammer or chisel hammer, the bellows located between the housing and the handle, or between two housing parts, is subjected to high mechanical stresses. This can lead to damage to the bellows due to fatigue. The result is usually cracks in the bellows. Large temperature fluctuations can further promote cracking, as they make the bellows brittle. If cracks occur in the bellows, air is drawn uncontrollably into the interior of the housing.

[0011] The present invention is concerned with the objective of providing a hand-held power tool, in particular a rotary hammer or chisel hammer, which is particularly robust and enables controlled cooling airflow.

[0012] To solve the problem, the hand-held power tool with the features of claim 1 is proposed. Advantageous embodiments of the invention can be found in the dependent claims.

[0013] Disclosure of the invention

[0014] The proposed hand-held power tool, which may in particular be a rotary hammer or chisel hammer, comprises a housing, preferably having several housing parts, a striking mechanism housed within the housing, an electric motor housed within the housing for driving the striking mechanism, and a handle part movably mounted relative to the housing. According to the invention, the handle part engages in a collar section of the housing, which surrounds the handle part without contact on at least three sides, preferably all around, forming a defined ventilation gap. The collar section surrounding the handle part without contact eliminates the need for a bellows between the housing and the handle part. Eliminating this component increases the robustness of the hand-held power tool. The protective function of the bellows is assumed by the collar section, as it surrounds the handle part.The ventilation gap formed between the collar section and the handle is covered by the collar section. At the same time, the collar section creates a defined ventilation gap between the housing and the handle, ensuring controlled ventilation and thus cooling of the electric motor housed within. The ventilation gap can be designed and dimensioned to reduce the flow velocity of the incoming ambient air. This prevents unwanted suction effects, such as the intake of loose work clothing.

[0015] Eliminating the bellows also reduces the number of parts and thus the cost of the handheld machine tool. Furthermore, weight can be saved, which is another advantage for a handheld machine tool.

[0016] The housing of the proposed hand-held power tool preferably comprises several housing parts. The multi-part design of the housing facilitates the assembly of the hand-held power tool.

[0017] Preferably, the collar section of the housing is formed by at least one U- or C-shaped housing part and / or at least one wing-like housing part. A U- or C-shaped housing part has the advantage that it can be arranged to already surround the handle on three sides. In the case of a U-shaped housing part, it can, for example, encompass the handle from above, resulting in a U-shaped collar section. A lateral extension of the U-shaped collar section can be achieved by means of a wing-like housing part. Preferably, a wing-like housing part is arranged on both sides of the handle to extend the collar section. If a circumferential collar section is to be formed, a second U-shaped housing part can be attached to the first U-shaped housing part. The second housing part then encompasses the handle from below.The two U-shaped housing parts then form a circumferential collar section composed of two half-shells. The latter can also be achieved using two C-shaped housing parts, which are positioned to the side of the handle part, so that each half-shell surrounds the handle part from one side.

[0018] In a further development of the invention, it is proposed that an air guide element for forming and / or covering at least one cooling air channel is arranged in the housing. This air guide element is connected to the ventilation gap via a window-like opening in the air supply element. To achieve controlled ventilation and / or cooling of the electric motor housed in the casing, not only is a defined ventilation gap required, but also a targeted flow of cooling air within the casing. For this purpose, at least one cooling channel is formed within the casing. The amount of air supplied to the at least one cooling channel via the ventilation gap can be adjusted via a window-like opening in the air supply element, which forms or at least covers the at least one cooling channel. Adjusting the air volume via the window-like opening allows for greater flexibility in the design of the ventilation gap between the casing and the handle.

[0019] Preferably, the housing comprises a pot-shaped housing section that accommodates the electric motor and is closed at the bottom by a lid-like housing section. For assembly, maintenance, and / or repair purposes, the lid-like housing section can be removed, thus providing access to the electric motor. Furthermore, the lid-like housing section preferably encloses a cavity that is connected to the at least one cooling air channel formed within the housing. The electric motor can then be supplied with cooling air via this cavity. Simultaneously, the cooling air from the at least one cooling channel can be redirected towards the electric motor via this cavity. The cooling air path thus leads through the cavity in the lid-like housing section.

[0020] Furthermore, it is proposed that damping elements be arranged within the housing for the movable mounting of the handle. These damping elements can be, in particular, springs and / or elements made of an elastically deformable material. The movable mounting of the handle via damping elements arranged within the housing results in vibration decoupling of the handle from the housing. The vibrations are largely absorbed by the damping elements. Consequently, during operation of the hand-held power tool, the handle is subjected to less vibration.

[0021] Advantageously, the damping elements are connected to the handle via at least one handle support. This at least one handle support facilitates the attachment of the handle to the damping elements. Preferably, the handle is detachably attached to the handle support. This allows the handle to be removed as needed, for example, to provide access to other components housed within the casing, particularly electronic components.

[0022] Furthermore, it is proposed that the ventilation gap between the housing and the handle has a minimum width of 0.5 mm, preferably 0.7 mm, and even more preferably 1 mm. This means that the ventilation gap is never less than 0.5 mm, preferably 0.7 mm, and even more preferably 1.0 mm, in any working position of the handle relative to the housing. This is because the working position of the handle can vary due to its movable mounting relative to the housing. The specified minimum width of the ventilation gap ensures that the handle does not contact the collar section of the housing in any working position, thus achieving effective vibration decoupling in every position. Since the range of motion of the handle relative to the housing increases with the size of the ventilation gap, the minimum width is preferably greater than 1.0 mm.

[0023] Preferably, a battery unit is provided to power the electric motor. The battery unit enables battery operation of the handheld power tool, making it usable anywhere. The cordless operation of the power tool also simplifies its handling. The battery unit is preferably housed in the handle, and more preferably in a battery compartment within the handle. The battery compartment can be designed as a holder or tray into which the battery unit is simply inserted, slid, or clamped. In this way, the battery unit can be easily removed from the battery compartment and placed in a charging station, for example, for charging.

[0024] Preferably, the handle also includes an actuating element for switching the hand-held power tool on and off. The hand gripping the handle to hold the power tool can then simultaneously switch the tool on and off. For this purpose, the actuating element is preferably designed as a switch located on the inside of the handle, so that it can be pressed by one or more fingers while holding the power tool.

[0025] A preferred embodiment of the invention is described in more detail below with reference to the accompanying drawings. These show:

[0026] Fig. 1 is a side view of a hand-held power tool according to the invention,

[0027] Fig. 2 shows a perspective view of the hand-held power tool of Figure 1 with the handle removed.

[0028] Fig. 3 shows a rear view of the hand-held power tool of Figure 1 ,

[0029] Fig. 4 shows an enlarged section of Figure 2 in the area of ​​an air supply element and

[0030] Fig. 5 shows a sectional view through the housing of the hand-held power tool of Figure 1 in the area of ​​an electric motor housed in the housing.

[0031] Detailed description of the drawings

[0032] Figures 1 to 5 show a hand-held power tool 1 with a housing 2 containing a percussion mechanism (not shown) and an electric motor 3 (see Figure 5). The hand-held power tool 1 has a tool holder 16 (see Figure 1) into which a tool (not shown), for example a drill bit or a chisel, can be inserted. The tool holder 16 defines a front face of the hand-held power tool 1. The hand-held power tool 1 also has a handle 4, which is accordingly located at a rear face of the hand-held power tool 1. A simple additional handle 15 is located further forward, that is, near the tool holder 16.

[0033] The hand-held power tool 1 is primarily held and guided by the handle 4 located at the rear. An actuating element 17 in the form of a switch is also located on the inside of the handle 4, by means of which the hand-held power tool 1 can be switched on and off. Furthermore, the handle 4 houses a battery unit 13 in a battery compartment 14 for powering the electric motor 3. The battery compartment 14 allows for easy removal of the battery unit 13 for charging (see Figure 2, which shows the handle 4 without the battery unit 13). After charging, the battery unit 13 can simply be inserted or slid back into the battery compartment 14.

[0034] The handle 4, located on the rear of the hand-held power tool 1, is movably mounted relative to the housing 2. Damping elements 11 and handle supports 12 connected to these damping elements 11 are incorporated into the housing 2 for this movable mounting (see Figure 2). This movable mounting relative to the housing 2 requires that the handle 4 and the housing 2 do not make contact and that they do not come into contact with each other when the handle 4 moves relative to the housing 2. This is ensured by the handle 4 engaging a collar section 5 of the housing 2, forming a ventilation gap 6 (see Figure 3). The collar section 5 surrounds the handle 4 along its entire length without contact. In this way, the handle 4 and the collar section 5 not only form a defined ventilation gap 6, but also eliminate the need for a bellows as a cover.

[0035] The housing 2 of the illustrated hand-held power tool 1 comprises several housing parts, with the collar section 5 being formed by a U-shaped first housing part 2.1 and two wing-like further housing parts 2.2 (see Figures 3 and 4). The U-shaped first housing part 2.1 forms an upper end of the housing 2. The two wing-like further housing parts 2.2 are attached to it on both sides, resulting in a substantially U-shaped collar section 5 that surrounds the handle part 4 on at least three sides. The two wing-like housing parts 2.2 can be formed integrally with or connected to a cup-shaped housing part 2.3, the cup-shaped housing part 2.3 housing the electric motor 3 (see Figure 5). The cup-shaped housing part 2.3 is closed at the bottom by a lid-like further housing part 2.4, in which a cavity 10 is formed (see Figure 5).A cooling air path leads through the cavity 10 to cool the electric motor 3. For this purpose, the cavity 10 is connected to the ventilation gap 6 via at least one cooling air channel 8.

[0036] As can be seen particularly in Figure 4, several cooling air channels 8 are formed in the housing 2, which are covered by an air supply element 7 with a window-like opening 9. The cooling air channels 8 are connected to the ventilation gap 6 via the window-like opening 9, so that the amount of air supplied to the electric motor 3 for cooling can be adjusted via the free cross-section of the opening 9. The opening 9 thus allows greater freedom in the design of the ventilation gap 6. In particular, the ventilation gap 6 can be dimensioned sufficiently large to prevent contact between the handle part 4 and the collar section 5 of the housing 2 in any working position.

[0037] 1 hand tool 2 housing

[0038] 2.1 Housing part 2.2 Housing part 2.3 Housing part 2.4 Housing part

[0039] 3 Electric motor

[0040] 4 Handle part

[0041] 5 Collar section

[0042] 6 ventilation gap

[0043] 7 Air supply element 8 Cooling air duct

[0044] 9 Opening

[0045] 10 Cavity

[0046] 11 Damping element 12 Handle carrier

[0047] 13 Battery unit

[0048] 14 Battery Garage

[0049] 15 Handle part

[0050] 16 Tool holder 17 Actuating element

Claims

REQUIREMENTS 1. Hand-held power tool (1), in particular a rotary hammer or chisel hammer, comprising a housing (2) which preferably has several housing parts, a striking mechanism received in the housing (2), an electric motor (3) received in the housing (2) for driving the striking mechanism and a handle part (4) which is movably mounted relative to the housing (2), characterized in that the handle part (4) engages in a collar section (5) of the housing (2), which surrounds the handle part (4) on at least three sides, preferably all around, without contact, forming a defined ventilation gap (6).

2. Hand-held power tool (1) according to claim 1, characterized in that the collar section (5) is formed by at least one U- or C-shaped housing part (2.1) and / or at least one wing-shaped housing part (2.2).

3. Hand-held power tool (1) according to claim 1 or 2, characterized in that an air guide element (7) is arranged in the housing (2) for forming and / or covering at least one cooling air channel (8), which is connected to the ventilation gap (6) via a window-like opening (9) in the air supply element (7).

4. Hand-held power tool (1) according to one of the preceding claims, characterized in that the housing (2) has a pot-shaped housing part (2.3) accommodating the electric motor (3), which is closed at the bottom by a lid-like housing part (2.4) which preferably encloses a cavity (10) which is connected to the at least one cooling air channel (8).

5. Hand-held power tool (1) according to one of the preceding claims, characterized in that damping elements (11) for the movable mounting of the handle part (4) are arranged in the housing (2).

6. Hand-held power tool (1) according to claim 5. characterized in that the damping elements (11) are connected to the handle part (4) via at least one handle carrier (12).

7. Hand-held power tool (1) according to one of the preceding claims, characterized in that the ventilation gap (6) has a minimum width of 0.5 mm, preferably 0.7 mm, and more preferably 1 mm.

8. Hand-held power tool (1) according to one of the preceding claims, characterized in that a battery unit (13) is provided for supplying power to the electric motor (3), which is preferably housed in the handle part (4), and further preferably in a battery garage (14) of the handle part (4).

9. Hand-held power tool (1) according to one of the preceding claims, characterized in that the handle part (4) has an actuating element (17) for switching the hand-held power tool (1) on and off.

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