EP0976505A2 - Handheld drilling machine - Google Patents

Abstract

The hand drill has a second hammer mechanism (20) arranged inside the housing (2), for the production of axial hammer action, with the hammer action having an axial power and hammer action frequency, which is at least partially different from that of the first hammer mechanism (16) action. The drill or the chisel tool bit (7) clamped in the chuck (6) is selectively rotationally drivable from the first (16) or from the second (20) hammer mechanism or can be acted on from both hammer action mechanisms together axially, or without axial hammer action support.

Description

The invention relates to a hand drill with an impact mechanism for generating axial strikes according to the preamble of claim 1.

In the fastening and dismantling technology, hand drills are known, some Have rotary drive for a drilling tool and with an impact mechanism for generation are equipped with impulsive impacts that are transmitted to the tool become. The axial strokes support the degrading effect of the drilling tool especially when drilling in brittle failure substrates, such as Concrete, stone, brick masonry and the like. For machining very hard and compact substrates, such as concrete and stone, prove themselves Hand drills as very useful with an electropneumatic hammer mechanism are equipped. Such hand drills are well known and are distributed for example by the applicant. The electro-pneumatic hammer mechanism This hand drill is for the generation of axial blows with a high Single impact energy of, for example, about 2 J to about 8 J at a proportional rate low impact frequency of, for example, about 45 Hz to about 80 Hz. Because of the large single impact energy of the axial impacts, hand drills are suitable for the processing of hollow brick masonry is less suitable.

In addition to the hand drills with electropneumatic hammer mechanism are also Hand drills are known which have a mechanical hammer mechanism. These include the Ratchet drilling machines known primarily for the DIY sector and those in the semi-professional and professional field used hand drills with Spring striking mechanism or spring-cam striking mechanism. The striking mechanism of this Known hand drills produce axial blows with a relatively small Single impact energy of, for example, about 0.03 J to about 0.3 J with a relative high impact frequency, which is for example up to about 700 Hz. Because of the little ones Single impact energy can also be used with such hand drills as hollow brick masonry can be processed with impact support without destroying the hollow brick. For the Processing of hard surfaces, such as concrete or stone Hand drills with mechanical striking mechanism less used. Because of the low Single impact energy of the axial impact, the user must use the hand drill press relatively hard against the subsoil and the achievable drilling progress is for the professional users generally too small.

For processing various substrates, such as concrete and hollow brick masonry, are thus two or more hand drills with axial impact support required, the axial strokes of which are suitable for the respective subsurface Have single impact energy and impact frequency to the ground with a to process sufficient drilling progress without damaging it. Buildings generally do not have a homogeneous structure throughout. For example In buildings, load-bearing parts consist of concrete and the intermediate parts Sections often made of brick masonry, especially of hollow brick masonry. The User who drilled holes or breakthroughs on these different substrates or the like, so far has always had to be at least two hand drills provide with different striking mechanisms for different impact energies. Since he cannot be expected to constantly have two or more Carries hand drills with it, leads to the procurement of the respective underground suitable device for undesirable delays.

The object of the present invention is therefore to overcome these disadvantages of the prior art Remedy technology. The user should be able to do so without major Decelerate the surface with the same hand drill and the one for it to work on a suitable working point.

The solution to this problem consists in a hand drill with the characteristic Features of claim 1. The Hand drill according to the invention is provided with a within a housing arranged striking mechanism for generating axial strikes on a in a Tool holder of the hand tool clamped, rotatable drilling or Chisel tools are transferable. Inside is additional arranged a second striking mechanism for generating axial strikes, the axial Beats have an impact energy and a beat frequency that are partial is different from the impact energy and the beat frequency that of the first Striking mechanism generated axial strikes. The clamped in the tool holder Drilling or chisel tools are either from the first or from the second Striking mechanism or of both striking mechanisms together with axial strikes actable. Axial stroke support is also complete for special applications can be switched off.

The hand drill according to the invention combines several hand drills Impact mechanisms for partially different single impact energies and Beat frequencies in one device. By using the hand drill with the first Striking mechanism for axial strikes with high single impact energy and lower Impact frequency or with the additional impact mechanism for axial impacts with smaller Single impact energy and higher single impact energy or with both striking mechanisms can be operated together, its performance can be very easily passed on to the different Surfaces to be adjusted. It is no longer necessary to have multiple hand drills with striking mechanisms for axial strikes with different single impact energies and To provide impact frequencies. The percussion parameters of the percussion mechanism of the Hand drills can be directly adapted to the respective surface at the place of work. It goes without saying that the hand drill also without axial impact support can be operated in that both striking mechanisms can be switched off. This mode is for example for drilling at high speed and without axial impact support in Wood and metal desirable.

For the flexibility of using the hand drill on a variety of different on solid substrates, it proves advantageous if the single impact energies of the axial strikes generated by the first striking mechanism and the second striking mechanism in the Ratio of about 6: 1 to about 250: 1, preferably about 10: 1 to about 40: 1, stand and their beat frequencies a ratio of about 1: 1.1 to about 1:15 exhibit.

It turns out to be useful if the first hammer mechanism is electropneumatic Percussion mechanism with an excitation piston arranged inside a guide tube, a flying piston and one in the axial extension of the guide tube arranged drill or chisel tool acting striking element. The second percussion mechanism is preferably a mechanical percussion mechanism which is compatible with the Interlocking element interacts. The differences in single impact energies and Percussion frequencies of the percussion mechanisms are, for example, completely different Strike generation of electro-pneumatic and mechanical striking mechanisms achievable.

The mechanical hammer mechanism can be used as a simple ratchet hammer mechanism or as Spring clip striking mechanism be formed. In constructive terms and in spite of to achieve satisfactory drilling progress with lower impact performance a spring-cam striking mechanism as advantageous.

In order to have the largest possible area of application with differently firm substrates to cover, it proves to be advantageous if the electropneumatic hammer mechanism for generating axial impacts with large single impact energy from about 2 J to about 8 J and low impact frequency from about 45 Hz to about 80 Hz and the spring-cam striking mechanism for generating axial impacts with small Single impact energy of about 0.03 J to about 0.3 J and high impact frequency of about 50 Hz to about 700 Hz are formed.

For a space-saving design as possible, it proves useful if that Spring-cam striking mechanism coaxial to the guide tube of the electro-pneumatic striking mechanism arranged and axially penetrated by the striking element. This points Spring-cam percussion a cam ring, which is rotatably arranged in the housing, and a spring-loaded percussion piston. The percussion piston is relative to the Cam ring is rotatably arranged and has cams for axial Interact with the cams of the cam ring.

Conveniently, the percussion piston works with one that can be driven in rotation Machine spindle rotatably connected sleeve. The machine spindle forms at the same time the guide tube for the electropneumatic hammer mechanism. That from the Machine spindle torque introduced into the sleeve is preferred over a spherical torque transmission element can be transferred to the percussion piston. At the The percussion piston counteracts sliding of its cams against those of the cam ring the restoring force of a cylinder spring penetrated by the striking element translational moved away from the cams of the cam ring. After passing the largest stroke it is triggered and accelerated back into the starting position by the cylinder spring. In doing so, he strikes against one provided on the striking element Ring collar, which is in front of the cam ring. This prevents the axial blow is introduced into the housing via the cam ring.

The striking mechanisms of the hand drill can be optionally switched on and off. Is to for example, in addition to the switchability of the electropneumatic hammer mechanism for a switching element is provided for the mechanical percussion mechanism, by means of which the Cam of the percussion piston adjustable out of engagement with the cam of the cam ring are. In a particularly advantageous embodiment of the hand drill, the two striking mechanisms automatically, preferably depending on predefinable criteria during operation, operable to the impact energy and frequency of the adjust axial blows to the surface and thus the optimal working point adjust.

Fig. 1 ein Schema des erfindungsgemässen Handbohrgeräts;

Fig. 2 einen Axialschnitt der beiden Schlagwerke des Handgeräts; und

Fig. 3 das zusätzliche mechanische Schlagwerk in vergrössertem Massstab.

The invention is explained in more detail below with reference to an exemplary embodiment shown in the figures. Show it:

Figure 1 is a schematic of the hand drill according to the invention.

2 shows an axial section of the two striking mechanisms of the hand-held device; and

Fig. 3 shows the additional mechanical striking mechanism on an enlarged scale.

1 shows a block diagram of the hand drill equipped according to the invention, which is generally designated 1. It has a housing 2 with a handle 3, on which a main switch 4 for activating the hand drill 1 is arranged. The supply of electrical arranged within the housing 2 Components with energy take place via an electrical supply line, which is connected to the Reference number 5 is provided. On the opposite side of the handle 3 Housing 2 is a tool holder 6 into which a drilling or Chisel tool can be clamped, which is indicated in Fig. 1 with the reference numeral 7. An electric drive motor 8 is arranged within the housing 2. The Drive shaft 9 of the drive motor is connected to a gear arrangement 10 which has two outputs. One output of the gear arrangement 10 serves the Rotary drive of the drilling tool 7 clamped in the tool holder 6 an output-side drive shaft 11 of the gear arrangement 10 with a Bevel spur gear 12 provided with a rotationally engaged Circumferential toothing 13 of a machine spindle 14 stands, which is rotationally fixed to the Tool holder 6 is connected. A second shaft 15 at the exit of the Gear arrangement 10 serves to drive an electropneumatic hammer mechanism 16, which is arranged inside the machine spindle 14. The electropneumatic Striking mechanism 16 generated axial strikes are in the tool holder 6th clamped drilling tool 7 transferable. So far the structure of the Hand drill the well-known, axial impact-supported hammer drills as they for example, be sold by the applicant.

In contrast to the known hammer drilling devices, this is the invention Hand drill 1 equipped with a second hammer mechanism 20. The axial blows that generated by the second percussion mechanism 20 and that in the tool holder 6 clamped drilling tool 7 transmissible axial blows have a Single impact energy and a beat frequency that is different from that Single impact energy and impact frequency of the first, electropneumatic Striking mechanism 16 produced axial strikes. The second striking mechanism 20 is concerned preferably a mechanical hammer mechanism, for example a Ratchet hammer mechanism, a spring clip hammer mechanism or a spring-cam hammer mechanism.

Fig. 2 shows an axial section of the two striking mechanisms 16 and 20. The description is limited to the details necessary for understanding the invention. The second shaft 15 exits the gear unit drives an eccentrically mounted one Excitation piston 17 of the electropneumatic hammer mechanism 16. The exciter piston is guided inside the machine spindle 14, which serves as a guide tube and over their rotatably with the bevel spur gear 12 driven by the drive shaft 11 cooperating external toothing 16 is rotatable about the axis A. Through the eccentric articulation of the excitation piston 17, the rotary movement of the shaft 15 in a translation of the excitation piston 17 implemented within the guide tube 14. Fig. 2 shows the excitation piston 17 at its rear dead center before it again is moved axially in the direction of the tool holder 6. One within the Guide tube 14 located air cushion transmits the axial movement of the Excitation piston 17 on a flying piston 18, which thereby a periodic, axial back and Her movement accomplished. The forward movement of the flying piston 18 in the direction of Tool holder 6 is delimited by a striking element 19, which by the impacting piston 18 transmitted axial impact to the in the Tool holder 6 transmits clamped drilling tool 7. The between that Air piston 18 and the exciter piston 17 located air cushion prevents the rebounding piston 18 strikes the exciter piston 17. Electropneumatic striking mechanisms are well known from the prior art and are also part of the applicant's hammer drill rigs. It goes without saying that device-specific modifications to the electropneumatic hammer mechanism 16 can be provided without moving away from the basic principle described. The axial impacts that can be generated with such electropneumatic impact mechanisms, have a single impact energy of about 2 J to about 8 J and are included Beating frequencies from about 45 Hz to about 80 Hz are generated.

The second striking mechanism 20 is coaxial with the first, electropneumatic striking mechanism 16 arranged. It is designed and includes in particular as a spring-cam percussion mechanism a cam ring 21 which is non-rotatably held inside the housing 2, and one Percussion piston 22, which is rotatable relative to the cam ring 21 and against the restoring force a spring 23 is axially displaceable. The cam ring 21 and the percussion piston 22 are axially penetrated by the striking element 19. The spring 23 is supported on the one hand Percussion piston 22 and on the other hand on a sleeve 24, which with the machine spindle 14, which forms the guide tube for the electropneumatic hammer mechanism 16, is rotationally coupled. The torque of the machine spindle rotated by the drive motor 14 is on the one hand via the striking element 19 onto the tool holder 6 Transfer clamped drilling tool 7. On the other hand, the torque also introduced into the sleeve 24 and via a preferably spherical torque transmission member 25 transferred to the percussion piston 22. A switching element 31 enables switch off the spring-cam percussion mechanism.

FIG. 3 shows the spring-cam percussion mechanism 20 from FIG. 2 on an enlarged scale. The cam ring 21 and the percussion piston 22 are axial from the striking element 19 permeated. The cam ring 21 is rotatably connected to the housing 2, fixed for example by screws 32. It has cams 27 which are switched on State of the spring-cam percussion mechanism 20 are in engagement with cams 28 which on the the side of the percussion piston 22 facing the cam ring 21 are provided. The Torque of the rotating machine spindle 14 is coupled in the rotationally fixed Sleeve 24 initiated. That between the sleeve 24 and the percussion piston 22 in one Axial groove 26 arranged spherical torque transmission member 25 transmits this Torque on the percussion piston 22. During the percussion piston 22 relative to the Cam ring 21 rotates, the cams 27 and 28 slide against each other, and the Rotational movement of the percussion piston 22 is converted into a translational movement. Here, the percussion piston 22 against the restoring force of the spring 23, which is is supported on the one hand on the percussion piston 22 and on the other hand on the sleeve 24 moved backwards. The already biased spring 23 is around the stroke resulting from the Height of the cams 27 and 28 results in additional tension. With further rotation of the Percussion piston 22 relative to the cam ring 21, the largest stroke is exceeded Edges of the cams 27, 28 slide over one another and the translational Forward movement of the percussion piston 22 is released again. The cocked spring 23 accelerates the percussion piston 22 axially in the direction of the cam disk 21 until Collar 29 on the percussion piston 22 strikes against an annular collar 30 on the striking element 19. The collar 30 is in front of the cam ring 21 such that the axial Impact energy of the percussion piston 22 transferred to the striking element 19 and not in the cam ring 21 is initiated. The striking element 19 transmits the spring-cam percussion mechanism 20 generated axial impact on the in turn Tool holder clamped drilling tool.

The single impact energy of the axial generated by the spring cam mechanism 20 Blows depends on the preload of the spring 23 and the one that defines the stroke Height of the cams 27, 28 from. The spring-cam percussion mechanism is preferably for Generation of axial impacts with a single impact energy of approximately 0.03 J to about 0.3 J. The stroke frequency of the axial strokes depends on the number of in the circumferential direction interacting cams 27, 28 on the cam disc 21 or on the percussion piston 22. The axial strikes are preferably with a Impact frequency of about 50 Hz to about 700 Hz can be generated.

From the illustration in Fig. 3 it can be seen that the cams 27, 28 over the Switching element 31 can be disengaged from the spring-cam percussion mechanism 20 switch off. In Fig. 3, the switching element 31 as from outside the housing manually operated rotary slide link shown. It goes without saying that that Switching element 31 is also automatically switched on or in between the cams 27, 28. can be disengageable actuator that can be activated depending on predefinable criteria is. In the known hammer drills with electropneumatic hammer mechanism this can usually be switched on or off. In connection with the one or switchable spring-cam striking mechanism 20 results in a large possibility of variation for the operation of the hand drill according to the invention. In a first Operating variant, the hand drill can be operated without axial impact support. This can be used, for example, for drilling holes in steel or wood may be necessary, which are drilled only at high speed without axial impact support become. Further operating variants result from the optional activation of the first or second percussion. This supports the axial stroke either with high single impact energy and a relatively low frequency like this for example in concrete. Or the axial strokes are smaller Single impact energy and high impact frequency can be generated in order Drilling hollow brick masonry without destroying the brick. For Special applications also enable the simultaneous activation of both striking mechanisms.

The invention was based on the example of a hand drill with an electropneumatic Percussion mechanism and a spring-cam percussion mechanism explained. Alternative versions other percussion combinations can also be used within the inventive concept provide. For example, an electro-pneumatic hammer mechanism is included can be combined with a ratchet hammer mechanism or a spring-loaded hammer mechanism. There are hand drills can also be realized, the two mechanical striking mechanisms with different ones Have single impact energies and impact frequencies. In another Two electropneumatic hammer mechanisms can also be used in one hand drill be provided with which axial strikes with different single impact energies and beat frequencies can be generated.

Claims (10)

Hand drill with a striking mechanism (16) arranged within a housing (2) for generating axial impacts which can be transferred to a rotatable drilling or chiseling tool (7) clamped in a tool holder (6) of the handheld device (1), characterized in that that a second percussion mechanism (20) for generating axial impacts is arranged within the housing (2), the axial impacts of which have an impact energy and an impact frequency which is at least partially different from the impact energy and the impact frequency of those generated by the first impact mechanism (16) axial strikes, the drilling or chiseling tool (7) clamped in the tool holder (6) being able to be acted upon either with axial strikes either by the first (16) or the second (20) striking mechanism or by both striking mechanisms or being driven in rotation without supporting the axial striking mechanism. Hand drill according to one of claims 1, characterized in that the Single impact energies from the first striking mechanism (16) and the second Impact mechanism (20) produced axial impacts in a ratio of approximately 6: 1 to approximately 250: 1, preferably about 10: 1 to about 40: 1, and their Beat frequencies have a ratio of 1: 1.1 to 1:15. Hand drill according to claim 1 or 2, characterized in that the first Percussion mechanism (16) an electropneumatic percussion mechanism with an inside Guide tube (14) arranged exciter piston (17), a flying piston (18) and one arranged in the axial extension of the guide tube (14) or chisel tool (7) acting striking element (19) and the second Percussion mechanism is a mechanical percussion mechanism (20) with the striking element (19) interacts. Hand drill according to claim 3, characterized in that the mechanical striking mechanism (20) is a spring-cam striking mechanism. Hand drill according to claim 4, characterized in that the electropneumatic impact mechanism (16) for generating axial impacts with large Single impact energy from about 2 J to about 8 J and low impact frequency of about 45 Hz to about 80 Hz and the spring-cam striking mechanism (20) Generation of axial impacts with small single impact energy 0.03 J to about 0.3 J and high impact frequency of about 50 Hz to about 700 Hz are. Hand drill according to claim 4 or 5, characterized in that the Spring-cam percussion mechanism (20) coaxial to the guide tube (14) of the electropneumatic striking mechanism (16) arranged and from the striking element (19) is axially penetrated. Hand drill according to claim 6, characterized in that the spring cam Percussion mechanism (20) a cam ring (21) which rotates in the housing (2) is arranged, and comprises a spring-loaded percussion piston (22), the relative is rotatably arranged to the cam ring (21) and has cams (28) which for axial impact generation with the cams (27) of the cam ring (21) work together. Hand drill according to claim 7, characterized in that the Percussion piston (22) cooperates with a sleeve (24) which rotatably with a rotatably driven machine spindle is connected, which the guide tube (14) for the electropneumatic hammer mechanism (16) forms, the rotary movement of the Sleeve (24) via a preferably spherical torque transmission element (25) is transferable to the percussion piston (22) and this when it slides Cams (28) on those (27) of the cam ring (21) against the restoring force a cylinder spring (23) penetrated by the striking element (19) in translation can be moved away from the cams (27) of the cam ring (21) and when triggered strikes against a ring collar (30) provided on the striking element (19) is upstream of the cam ring (21). Hand drill according to one of the preceding claims, in particular according to Claim 7 or 8, characterized in that a switching element (31) is provided, by means of which the second, preferably mechanical, striking mechanism (20) can be switched on or off, for example by the cams (28) of the Percussion piston (22) of the spring-cam percussion mechanism out of engagement with the Cams (27) of the cam ring (21) are adjustable. Hand drill according to one of the preceding claims, characterized characterized that the first and second striking mechanism in dependence Predefinable criteria automatically, preferably during operation can be switched off.

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