EP3117958B1 - Handheld grinder - Google Patents

Description

It is a hand grinder with an electric drive and a drive shaft which is coupled with a rotatably mounted spindle orthogonal to the drive shaft via a gear assembly, a housing part for the transmission and a housing part connected thereto for at least a part of the spindle described (see, eg JP 201211513 A , which forms the basis for the preamble of claim 1). Such hand grinders are also known from the prior art as angle grinders or polishing machines. Described herein is a hand grinder having a port for a fluid, which fluid is applied to the surface to be processed during operation of the hand grinder.

As a drive for these hand grinders, for example, single-phase motors are used, which transmit the rotary motion to a perpendicular to the drive shaft rotatably mounted spindle via a gearbox. The spindle has at its lower end a threaded portion over which various machining tools, such as grinding wheels, can be attached. In order to ensure good handling of these hand grinders and to apply sufficient pressure to the surface to be machined, have the hand grinders usually a handle on the front housing part of the hand grinder, preferably in the region of the transmission housing, on.

The fluid supply to the surface to be machined or to a grinding wheel can be done in various ways. Hand grinders with a supply arrangement for the fluid at an upper side of the transmission housing are known from the prior art. A connecting piece and a fluid hose protrude from the top, so that it is difficult or no pressure from above the housing can be applied to the hand grinder. This is particularly disadvantageous because in this area the spindle is arranged. In addition, hand grinders are known which allow lateral supply of the fluid via feed nozzles, which are arranged on a housing part of the hand grinder. The fluid is then applied, for example, to the surface of a grinding wheel, which faces away from the tool surface to be machined.

DE 20 2004 008 100 U1 discloses an injection polisher in which a fluid conduit with fluid flow control valve is replaced by an on / off valve operable by the thumb of the hand holding the still handle of the injection polisher. In this injection polisher, the liquid is passed centrally through the spindle, wherein the supply also takes place via the top of the gear housing. For this purpose, the transmission housing has a rigid supply line, which leads away from the transmission housing outside of the injection polisher.

Furthermore, hand grinding machines are known, which have a connection for a fluid line on a lower housing part for the spindle. The fluid is transferred via this connection directly to the spindle, which has incorporated into the spindle surface area channels. About these channels can the fluid flow down and is introduced to the surface to be machined.

In these hand grinders, the housing parts for the drive have ventilation openings in order to cool the drive and prevent overheating. However, the heat development in the region of the transmission is problematic, whereby the housing part for the transmission can have no ventilation openings, since otherwise dust or fluid mist penetrates into the machine and can destroy it.

DE 10 39 878 A discloses a stone grinder with water connection for wet grinding, wherein a helical cooling coil is provided for cooling the motor. Water flows through the cooling coil for wet grinding. In addition, the motor is cooled by a fan, wherein the heated air is cooled by the guided in the cooling coil water.

DE 603 05 539 T2 discloses a gearbox for angle grinder. The transmission housing may be connected via corresponding openings with the housing of an engine, so that via a motor fan air is guided into the transmission housing and led out through openings in the transmission housing from the transmission housing.

US 2,238,096 discloses an angle grinder with a water supply in the transmission housing from above or laterally.

It is therefore an object to provide a hand grinder which allows cooling of the gear of the hand grinder and also provides a fluid supply, which improves the handling of the machine.

The object is achieved by a hand grinder having the features specified in claim 1. favorable Further developments are specified in the dependent claims in detail.

The arrangement of the first connection for the Fluidzuführleitung ensures that no means are arranged on the housing part for the transmission, which complicate the handling of the hand grinder. For example, with the hand grinder described herein, it is possible for a user to apply pressure to the top of the housing portion for the transmission or to sidewalls of the housing portion for the transmission. In addition, the guidance of the fluid conduit through the transmission housing and through the housing for the spindle ensures that the transmission is cooled. In this case, the fluid flows through the housing part for the transmission and the housing part for the spindle before it exits via the outlet opening. This allows the hand grinder to be cooled without it additional facilities for cooling the transmission must be provided. The arrangement of the at least one outlet opening can be provided so that, for example, the fluid can escape onto the tool surface to be machined over the spindle or through certain channels or outlet openings of the spindle and a correspondingly shaped grinding wheel over the surface of the grinding wheel. Additionally or alternatively, other outlet openings may be provided, which allow a fluid supply to the surface of the grinding wheel.

The line can be deflected several times in the housing part for the transmission and / or in the housing part for the spindle. The greater the path of the conduit through the housing part for the transmission and the housing part for the spindle, the greater the cooling effect through the conduit and the fluid flowing through the conduit. The line may, for example, spiral, in the form of a helix, wavy, zigzag or even in substantially orthogonal patterns through the housing part for the transmission and the housing part for the spindle run.

The line can run several times around the gear and / or the spindle around. The larger the area through the conduit surrounding the transmission and / or the spindle, the greater the cooling of the transmission and / or the spindle. The cooling also causes cooling of storage facilities. In addition, lubricants can be cooled, which are then also not heated too much.

The conduit section may be a hollow shaft extending through the spindle and having at least one outlet opening at its lower end. The hollow shaft is not rotatable and therefore can be connected directly to the line. The spindle is rotatably mounted around the hollow shaft. The hollow shaft has the at least one outlet opening. Furthermore, the hollow shaft may also have further openings, which open into corresponding openings in the spindle, so that a fluid outlet can be achieved via the spindle and corresponding channels in the spindle.

Alternatively, the conduit section may be a channel extending through the spindle, the channel being connected at the head end of the spindle via a sealing arrangement on the conduit and the spindle having at its lower end at least one outlet opening connected to the channel. In this embodiment, since the conduit section for the fluid is formed by the spindle itself and thus rotates during operation of the hand grinder, a seal arrangement is required, which is arranged in the connection area between the conduit and the channel. The seal assembly may, for example, have a sliding seal. For example, mechanical seals provide a secure seal over a long period of use.

The line may be arranged in or on the housing part for the transmission and / or in the housing part for the spindle. Preferably, the two housing parts, which may also be formed as a common housing part in all embodiments of the hand grinder described herein, incorporated channels. The channels serve as a conduit for the fluid and in particular run around the transmission. In such embodiments can be dispensed with separate line parts or the number and length of the required line parts can be significantly reduced. The formation of the channels in the housing parts can take place during an injection molding process for the production of usually made of plastic housing parts. This also reduces the production costs and the costs for the hand grinder. Thus, the first connection can also be formed in an injection molding process on the housing part for the spindle, which then opens into the corresponding channels. Only in the connection area between the line or the channel in the housing part to the spindle or the opening at the head end of the spindle, a hose or other tubular part may be provided. In further embodiments, the housing part for the transmission has a further connection which protrudes into the interior of the housing part for the transmission and is provided for example with a mechanical seal. On this mechanical seal can then be placed in the manufacture of the hand grinder, the head of the spindle, so that without a hose or other means, a fluid connection between the channel and the spindle is made. Alternatively, the hollow shaft can also be arranged from the connection on the inside of the housing part for the transmission. After the production, for example in an injection molding process, sealing means are arranged on the first connection to the housing part for the spindle so that the fluid supply line can be sealingly connected to the first connection. The formation of the conduit for the fluid through passages in the housing parts provides cooling of the transmission and the spindle without additional components and without an increased weight.

The hand grinder may further include a controller and a valve assembly coupled to the controller, wherein the valve assembly regulates the supply of fluid into the conduit and / or into the conduit portion.

• der Drehzahl der elektrischen Antriebswelle und/oder der Spindel und/oder
• der Temperatur im Gehäuseteil für das Getriebe, im Gehäuseteil für die Spindel und/oder des elektrischen Antriebs steuerbar sein.

The fluid supply can via the valve arrangement in dependence

• the speed of the electric drive shaft and / or the spindle and / or
• the temperature in the housing part for the transmission, be controllable in the housing part for the spindle and / or the electric drive.

In further embodiments, the hand grinder has a second connection on a holding region facing away from the spindle the hand grinder, wherein the fluid supply line is disposed on a bottom of the hand grinder and connected to the first port and the second port.

Furthermore, the second connection may be designed as a connection element for an external fluid connection and the hand grinder may have a second valve arrangement which regulates the fluid supply in accordance with the control unit and / or an actuating element.

Electrically powered hand grinders generally also have a switch for switching the hand grinder on / off. In this case, the second valve arrangement may be coupled to the on-off switch, so that a fluid supply via the second valve arrangement is automatically provided by switching on the hand grinder.

The fluid used may preferably be water, which is used primarily in the treatment of stone surfaces. In addition, sufficient cooling of the transmission and / or spindle is possible via the water. In particular, no cooling liquids have to be circulated and provided in the manual grinding machine, the discharge of which must be prevented due to environmental or safety regulations.

The spindle also has at its lower end a threaded portion, are connected via the example grinding wheels with the spindle. In addition, at least the housing part for the transmission have receptacles on the side walls, can be used in the handles.

Further advantages, features and design options will become apparent from the following description of the figures of non-limiting embodiments to be understood.

Fig. 1

eine perspektivische Ansicht einer Handschleifmaschine in schematischer Darstellung;

Fig. 2

eine schematische Seitenansicht der Handschleifmaschine von Fig. 1;

Fig. 3

eine schematische Seitenansicht von Komponenten einer Handschleifmaschine;

Fig. 4

eine schematische Vorderansicht von Komponenten einer Handschleifmaschine; und

Fig. 5

eine weitere schematische Vorderansicht von Komponenten einer Handschleifmaschine.

In the drawings shows:

Fig. 1

a perspective view of a hand grinder in a schematic representation;

Fig. 2

a schematic side view of the hand grinder of Fig. 1 ;

Fig. 3

a schematic side view of components of a hand grinder;

Fig. 4

a schematic front view of components of a hand grinder; and

Fig. 5

another schematic front view of components of a hand grinder.

Parts and components that are identified by the same reference numbers in the drawings essentially correspond to each other unless otherwise specified. Further, it is omitted to describe components and components which are not essential to understanding the teachings disclosed herein.

Fig. 1 shows a perspective view of a hand grinder 10 in a schematic representation. The hand grinder 10 is divided into a first region 12, a second region 14 and a third region 16. The first region 12 comprises a handle 18 by means of which the hand grinder 10 can be held with one hand. Furthermore, the first region 12 has a switch 19, which is provided for switching on and off a drive unit not shown in the figures. The switch 19 is a so-called on / off switch. The drive unit is a single-phase motor having a rotor and a stator. The rotor or the drive shaft is coupled via a gear arrangement with a spindle 36. The power supply for the electric motor via a port 22, either the terminal 22 is designed as a plug for an electrical cable or via the terminal 22, an electrical cable is guided into the hand grinder. The electrical cable can then have, for example, a power plug, via which the hand grinder 10 is connected to a power supply network. The first region 12 further has on the underside of the handle 18 on an operating lever 20 which sets the electric motor in operation. So that the electric motor and thus the hand grinder 10 can be put into operation via the operating lever 20, the switch 19 must first be actuated. The first region 12 also has a holder 24, on which a second connection 26 is held. The second port 26 is coupled to a fluid supply line 28. The second connection 26 has a standardized connection, so that a fluid line, for example a water-carrying line, can be connected via a corresponding connection connection. The water supplied via the second connection 26 can be introduced into the fluid supply hose 28 at a specific pressure via further devices (not shown). Furthermore, the operating lever 20 may be coupled to a valve arrangement which regulates the fluid or water supply via the second port 26 and the fluid supply line 28. When the operating lever 20 is actuated, the valve opens and the water is passed via the second port 26 and the fluid supply line 28 to a first port.

The second region 14 has a housing 30, which surrounds the drive unit or the electric motor. In the housing 30 further devices for the operation of the drive unit are also provided. These do not exhaustively include switching means, cables, cable clamps, bearing means and devices for storing the components.

The third region 16 includes at least one housing 32 for a transmission and a housing 34 for at least a portion of the spindle 36. The housing parts 32 and 34 may be in one piece or be formed as connectable housing parts. In the housing 32, a transmission is arranged, which transmits the rotational movement of the rotor of the drive unit via toothed and bevel gears on the spindle 36. The spindle 36 is rotatably mounted in the housing 32 and the housing 34 and protrudes with a threaded portion 38 from the housing 34. The housing 32 has receptacles 40 on opposite sides. For example, handles can be used in the receptacles 40, whereby the hand grinder 10 can be pressed against a surface during operation. Further, the hand grinder 10 can be pressed over the surface 42 on a surface to be machined. In this case, the surface 42 is free of other facilities, such as means for supplying water or other holding elements. This makes it possible to exert targeted pressure on the third region 16 in order to achieve a corresponding processing of surfaces. Through the threaded portion 38 different grinding wheels or other grinding and polishing can be firmly connected to the spindle 36.

The first region 12, the second region 14 and the third region 16 are connected to one another. For example, the first region 12, the second region 14 and the third region 16 are detachably connected to one another via screws. Furthermore, a protective cover may be attached to the housing 30, so that dust and mist do not enter the housing 30 in ventilation openings during operation of the hand grinder 10. So that no dirt or moisture can penetrate into the housing 32 and 34, they have no ventilation openings and are formed closed. Furthermore, especially the lower portion of the housing 34 with an opening for the spindle 36 on an encircling seal.

Fig. 2 shows a schematic side view of the hand grinder 10 of Fig. 1 , In this illustration, the fluid path of the water is shown schematically over the thick line. The arrows 60 show the flow path of the water.

The fluid supply line 28 extends from the holder 24 on the underside 29 of the hand grinding machine 10 to a first connection 44. The first connection 44 is arranged on the housing 34. From the first port 44, a conduit 46 extends in the housings 34 and 32 up to the top 42 of the housing 32. From there, the conduit 46 extends to a head end 37 of the spindle 36 and passes through the spindle 36 in a line section 48 down to the threaded portion 38. In a first embodiment, the conduit portion 48 is a channel in the spindle 36. In a joint 50 between the conduit 46 and the channel in the spindle 36, a mechanical seal is provided which prevents leakage of water. The conduit section 48 and the channel then rotate in operation of the hand grinder 10. The channel in the spindle 36 terminates at the bottom of the spindle 36 in at least one outlet opening. The outlet opening may be provided on the underside of the threaded portion 38 or circumferentially on an overlying area. Preferably, the water enters via the channel at a lower outlet opening in the region of the threaded portion 38, so that the surface to be treated is moistened.

In a further embodiment, the conduit section 48 is formed by a hollow shaft which extends from a connection point 50 through the spindle 36. The hollow shaft then ends in the lower region of the spindle 36 in the threaded portion 38 and guides the water to the area to be machined. During operation of the hand grinding machine 10, the spindle 36 rotates about the hollow shaft.

The spindle 36 is formed so that it is coupled via the bevel gears and gears with the drive unit, ie the electric motor. For example, different rotational speeds of the spindle 36 can be set via the transmission. Furthermore, also via the electric motor, the rotational speed be adjustable. For this purpose, the hand grinder 10 may for example have a controller.

The guidance of the conduit 46 upwards and through the housing 34 and the housing 32 also ensures that at least the transmission is cooled via the water taken up in the conduit 46. Accordingly, a heat transfer from the transmission to the fluid or the water takes place, so that over the outlet opening in the region of the threaded portion 38, a heated water is discharged. However, heating the water is not detrimental to the processing of stone surfaces, for example, but may even be beneficial.

The water supplied via the second port 26 flows via the fluid supply line 28 to the port 44 and from there via the line 46 through the housing 32 and the housing 34 to the line section 48 and from the line section 48 via an outlet opening on the spindle 36 or a hollow shaft.

In further embodiments, the first connection 44 is produced in one piece with the housing 34, for example in an injection molding process. Only sealing means are then attached to the first connection 44, so that the fluid supply line 28 can be tightly connected to the first connection 44. Further, during manufacture of the housings 32 and 34, channel structures are introduced into the sidewalls of the housing 32 and the housing 34, these conduits serving as conduit 46. For this purpose, the inside of the housing 32 is formed in the region of the connection point 50 as a further connection, so that water from a channel in the housing 32 via the connection point 50 either directly into a trained as a hollow shaft section 48 or via a arranged at this connection mechanical seal in a channel the spindle 36 is guided. In these embodiments, no separate lines 46 must be laid so that achieved without additional weight cooling of the transmission and the spindle can be. In addition, a water supply is provided without having to arrange water supply means on the outer walls of the housings 32 and 34 located in the work area. This allows a user, especially in the area of the housing 32 in the desired manner by applying the hand or otherwise exert pressure to apply a corresponding pressure on the surface to be machined. Advantageously, 42 pressure can be applied over the entire top.

The arrangement of the fluid supply line 28 and the first port 44 on the bottom 29 of the hand grinder 10, these are not in sight and in the workspace of a user, so that the handling of the hand grinder 10 is significantly improved.

Fig. 3 shows a schematic side view of components of a hand grinder 10. In Fig. 3 In particular, the housing 32 and the housing 34 and a part of a fluid supply line 28 are shown. The formation of the line 46 and the line section 48 substantially corresponds to that in the FIGS. 1 and 2 Hand grinder 10 shown in particular Fig. 3 the fluid path of the water from a junction 52 from the first port 44 through the spindle 36th Fig. 3 shows how the conduit 46 and the conduit 46 formed by the channels in the housing parts 32 and 34 on the side walls of the housing 32 and 34 extends.

Fig. 4 shows a schematic front view of components of a hand grinder 10. As the representation of Fig. 4 can be taken, the channels are mainly in the area of in Fig. 4 not shown gear formed meandering, so that a large cooling surface is provided. In further embodiments, the channels formed in the housing walls of the housings 32 and 34 may have other structures.

It is further pointed out that the flow pattern shown in the figures is only an example, wherein the conduit 46 formed by the channels can always run in the housing walls of the housings 32 and 34 or only in sections.

Fig. 5 shows a further schematic front view of components of a hand grinder 10. In the illustration of Fig. 5 Run lines 46, which may be formed, for example, again as channels in the housing parts of the housing 32 and 34, on the outer sides, wherein the lines or channels, the transmission (in Fig. 5 not shown) in the form of a square surrounded. In Fig. 5 The lines 46 and the channels protrude beyond their points of connection with other channels or lines 46. However, this illustration is only an example, although other forms are possible.

The in the Fig. 1 to 5 Hand grinders 10 shown further comprise further components such as springs, bearing rings, gaskets, bolts, screws, etc., which are not shown and described. Further, the hand grinders 10 have a thread that couples the drive shaft to the spindle 36. The drive shaft and the spindle 36 in this case run at a right angle to each other, so that via a bevel gear of the drive shaft, a corresponding toothed or bevel gear of the spindle 36 is driven. The spindle 36 is fixedly connected to this bevel gear or can be releasably connected to the bevel gear via locking means. Furthermore, the spindle 36 is secured against falling out. Through the threaded portion 38 different grinding wheels or other abrasive can be attached. The hand grinder 10 is then placed on a surface to be machined, such as a stone surface, that the bottom or the tool side of the grinding wheel rests on the surface. In operation of the hand grinder 10, a grinding wheel is rotated and supplied with water via the above-described means, the water supply additionally causes cooling of the gear assembly in the hand grinder 10.

LIST OF REFERENCE NUMBERS

10

hand grinder

12

first area

14

second area

16

third area

18

Handle

19

switch

20

operating lever

22

connection

24

bracket

26

second connection

28

fluid supply line

29

bottom

30

casing

32

casing

34

casing

36

spindle

37

headend

38

threaded portion

40

admission

42

top

44

first connection

46

management

48

line section

50

junction

52

junction

60

arrow

Claims (10)

1. Portable grinder, at least comprising an electric drive, a drive shaft coupled by way of a transmission arrangement with a rotatably mounted spindle (6) arranged orthogonally to the drive shaft, a housing part (32) for the transmission and a housing part (34) connected therewith for at least a part of the spindle (6), wherein

   - the lower end of the spindle (36) at which the processing tool can be mounted projects out of the lower region of the housing part (34) for the spindle (6)

   - the housing part (34) for the spindle (36) has a first connection (44) for a fluid feed line (28)

   - the first connection (44) is arranged at the lower region of the housing part (34) for the spindle (36),

   - at least one outlet opening is provided at the lower end of the spindle (36) and the portable grinder is characterised in that

   - a line (46) runs upwardly from the first connection (44) through the housing part (34) for the spindle (36) and through the housing part (32) for the transmission and

   - the line (46) at a head point (37) of the spindle (36) goes over into a downwardly directed line section (48) extending through the spindle (36).
2. Portable grinder according to claim 1, wherein the line (46) is deflected a plurality of times in the housing part for the transmission and/or in the housing part for the spindle (36).
3. Portable grinder according to claim 1 or 2, wherein the line (46) runs a plurality of times around the transmission and/or the spindle (36).
4. Portable grinder according to any one of claims 1 to 3, wherein the line section (48) comprises a hollow shaft which extends through the spindle (36) and which has at least one outlet opening at its lower end.
5. Portable grinder according to any one of claims 1 to 3, wherein the line section (48) is a channel extending through the spindle (36), the channel is connected at the head point (37) of the spindle (36) with the line (46) by way of a sealing arrangement and the spindle (36) has at the lower end thereof at least one outlet opening connected with the channel.
6. Portable grinder according to any one of claims 1 to 5, wherein the line (46) is arranged in or at the housing part for the transmission and/or the housing part for the spindle (26) or is formed by channels in the housing part for the transmission and/or the housing part for the spindle (36).
7. Portable grinder according to any one of claims 1 to 6, comprising a control unit and a valve arrangement which is coupled with the control unit and which is constructed for the purpose of regulating the feed of fluid in the line (46) and/or in the line section (48).
8. Portable grinder according to claim 7, wherein the portable grinder is so constructed that the fluid feed is controllable by way of the valve arrangement in dependence on

   - the rotational speed of the electric drive shaft and/or of the spindle (36) and/or

   - the temperature in the housing part for the transmission, in the housing part for the spindle (36) and/or of the electric drive.
9. Portable grinder according to any one of claims 1 to 8, comprising a second connection (26) at a holding region, which is remote from the spindle (36), of the portable grinder (10), wherein the fluid feed line (28) is arranged at an underside (29) of the portable grinder (10) and connected with the first connection (44) and the second connection (26).
10. Portable grinder according to claim 9, wherein the second connection (26) is constructed as a connecting element for an external fluid connection and the portable grinder (10) comprises a second valve arrangement, which is constructed for the purpose of regulating the fluid feed according to the control unit and/or an actuating element.

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