EP0522190A1 - Sound attenuated chuck for hydraulically or pneumatically powered impact- and drillhammers - Google Patents

Abstract

In pneumatically or hydraulically powered impact or drilling tools with open retaining cap (2), the sound of the piston percussion on the working tool (4) - chisel or drill rod - passes unhindered and without attenuation through the latter into the open. Through the installation of sound-reflecting and sound-absorbing devices, a noise level is to be reached which corresponds to pneumatic hammers with closed retaining cap and sound-insulating casing. A bush (14) of wear-resistant and sound-absorbing material in which a multiplicity of apertures (14a) are arranged continuously to the inside on its outer periphery has been developed for this purpose. These sound-insulating bushes are fastened between the retaining cap (2), the retaining pawl (3) and the tool-holder cylinder (5) in the case of pneumatic hammers or in the area of the front cylinder and the tool retaining clip in the case of drilling hammers. The push-in tool (4) moves inside the sound-insulating bush (14) encasing it. <IMAGE>

Description

The invention relates to a compressed air-operated or hydraulically operating percussion and drilling tool, so-called pneumatic or hydraulic hammer, with a hammer cylinder acting on a plug-in tool by a percussion piston, with an open holding cap for receiving a tool holding pawl, a tool holding bracket or a similar holding element.

Compressed air and hydraulically operated impact and drilling tools, so-called compressed air or hydraulic hammers, are used in the entire construction industry.

The principle of operation of these hammers - regardless of the type of drive - is that a percussion piston is a working tool - e.g. a point iron, a spade or a boring bar - applied to its impact surface and driving it into the material to be split or drilled.

The working tool is usually carried out in the case of impact tools for securing against rotation, in the case of drilling tools for transmitting the rotary movement to the boring bar, with a hexagon in the area of the tool holder.

The hammers designated are equipped with a holding cap which, among other things, receives a tool holding pawl, a tool holding bracket or a similar holding element.

The working tool is freely movable in its longitudinal axis in the area of the tool holder within its collar system - on the one hand by the holding element and on the other hand by the system on the tool holder.

According to the current state of the art, the sound of the piston impact noise on the working tool and, in the case of pneumatic hammers, the sound pressure of the expanding working air flowing past the tool holder is usually released unhindered and undamped through the tool holder.

In the case of a tool according to US 37 83 970, the working noise is insufficiently damped. In this pneumatic hammer, the sound emerging from the lower retaining cap is damped by a device which is attached to the insert tool as a double-shell-shaped sleeve made of steel and rubber and extends into the retaining cap.

A holding pawl is used to hold the insertion tool, which acts directly on the unprotected insertion tool (chisel or boring bar) and thereby considerably reduces the sound absorption in this area.

From DE-29 26 449 a muffler for a rotary hammer is known, which shows a sleeve arranged on the front of the rotary hammer and surrounding the shaft directly protruding from the rotary hammer, which sleeve consists of sound-absorbing material and is pushed over a sleeve, which is the joint releasably connects between the drill shaft and the drill rod.

In the case of pneumatic hammers according to DE-39 05 248 A1 with a closed retaining cap and sound insulation jacket made of elastic material, on the other hand, the sound outlet is encapsulated, so that these hammers of the same type are 3 - 4 dBA (measured at a distance of 6 m) quieter, i.e. can be reduced to 82 - 83 dBA.

The object of the invention is to provide effective sound insulation for pneumatic or hydraulically operated percussion or drilling tools, so-called compressed air or hydraulic hammers, with open holding caps with tool holding pawl, tool holding bracket or another holding element in the area of the emerging sound by incorporating sound reflecting and sound absorbing devices to ensure that a noise level emerges and is measured that corresponds at least to the noise level of pneumatic hammers with the retaining cap and soundproofing jacket closed.

The invention solves the problem in the manner in which the features of the claims specify.

According to the invention the area of the sound outlet within the tool holder is designed in such a way that a wear-resistant, sound-absorbing and non-metallic bushing is arranged in the case of pneumatic or hydraulic hammers with an open holding cap, with a tool holding pawl for the striking tool or with a tool holding bracket for the boring bar. In the case of pneumatic hammers, this bushing is arranged in the region of the holding cap, tool holder and insertion tool, and in the case of rotary hammers, expediently in the region of the tool holding bracket, front cylinder, drill sleeve, wear bushing and boring bar.

The sound-reflecting and sound-absorbing measures, according to the criteria of which the socket is designed on the inside, consist in the fact that, for example, a perforated socket is used which is continuously provided on the outer circumference with a large number of bores / openings.

The same sound-reflecting and sound-absorbing results can be achieved if, instead of perforated bushings, parallel-grooved bushings with a plurality of radially arranged transverse grooves in the inner part of the bushing or swirl-grooved bushes with helically arranged grooves in the inner part of the bushing are used.

Instead of perforated, parallel-grooved or swirl-grooved bushings, bushings with individual recesses of any design and number distributed over the inner circumference can also be used as sound-reflecting and sound-absorbing measures in compressed air or rotary hammers with an open retaining cap.

For use with drilling tools, an embodiment is also conceivable in which the soundproofing sleeve is part of the drill sleeve, i.e. in this case the lower part of the steel drill sleeve has openings or recesses which are intended to absorb the sound.

The sound waves passing through this inner region of the socket are reflected and absorbed in the bores, transverse grooves or other recesses, so that this measure reduces the Sound level is reached and the sound pressure waves penetrating the tool bundle into the open are reduced by 3 - 5 dBA, measured at a distance of 6 m.

As a material for the bushing according to the invention, for example, plastics or plastics-like materials can be selected which, on the one hand, must be insensitive to the action of lubricating oils and greases, and, on the other hand, should be wear-resistant and heat-insensitive to possible friction from the striking or rotating insertion tools, such as chisels or boring bars .

Fig. 1

zeigt eine Werkzeugaufnahme eines Drucklufthammers mit offener Haltekappe ohne Schallschutzmaßnahme;

Fig. 2

zeigt eine Werkzeugaufnahme eines Drucklufthammers mit der beanspruchten Schallschutzmaßnahme, ausgeführt als gelochte Buchse;

Fig. 3

zeigt eine Ausführungsmöglichkeit der Buchse als gelochte Buchse;

Fig. 4

zeigt eine Ausführungsmöglichkeit der Buchse als parallel genutete Buchse;

Fig. 5

zeigt eine Ausführungsmöglichkeit der Buchse als drallgenutete Buchse;

Fig. 6

zeigt die Werkzeugaufnahme eines Bohrhammers mit offener Haltekappe ohne Schallschutzmaßnahme,

Fig. 7

zeigt die Werkzeugaufnahme eines Bohrhammers mit offener Haltekappe und schalldämmender Buchse.

Embodiments of the invention are explained in more detail with reference to the schematic drawings.

Fig. 1

shows a tool holder of a pneumatic hammer with an open retaining cap without soundproofing measure;

Fig. 2

shows a tool holder of a pneumatic hammer with the claimed soundproofing measure, designed as a perforated bushing;

Fig. 3

shows an embodiment of the socket as a perforated socket;

Fig. 4

shows an embodiment of the socket as a parallel-grooved socket;

Fig. 5

shows an embodiment of the socket as a swirl-grooved socket;

Fig. 6

shows the tool holder of a rotary hammer with an open holding cap without noise protection measure,

Fig. 7

shows the tool holder of a rotary hammer with an open retaining cap and sound-absorbing bush.

In Fig. 1 the area of the tool holder of a pneumatic hammer (1) with an open holding cap (2) is shown without soundproofing.

The working principle of these hammers is that a percussion piston (6) an insertion tool (4), designed as a point or spade, executed in Figures 6 and 7 as a boring bar, applied to the impact surface (7) and the insertion tool (4) into the material that is to be split or drilled is of great hardness, strength, toughness, etc. The insertion tool (4) is usually carried out in the case of impact tools for securing against rotation with a hexagon (4a) in the region of the tool holding cylinder (5).

The insertion tool (4) is freely movable in its longitudinal axis in the area of the tool holding cylinder (5) within its collar system - on the one hand by the holding pawl (3) and on the other hand by the contact with the tool holding cylinder (5).

The piston impact noises that occur on the impact surface (7) of the percussion piston (6) and insertion tool (4), and in the case of pneumatic hammers, the sound pressure of the expanding at which Tool holding cylinder (5) flowing through working air, passes through the holding cap (2) unhindered and undamped into the open.

Fig. 2 shows the area of the tool holder cylinder (5) of a pneumatic hammer (1) with an open holding cap (2) and tool holding pawl (3), in which a perforated sound insulation sleeve (14, 14a) is attached as a soundproofing measure. This sound insulation bushing (14, 14a) is inserted between the holding cap (2) and the tool holder cylinder (5) or detachably fastened to the inner wall of the holding cap (2).

3 - 5 show different possible configurations of the socket.

Fig. 3 shows a soundproofing sleeve (14) made of wear-resistant, sound-absorbing and non-metallic material with a plurality of bores (14a), which are arranged continuously on their outer circumference inwards.

Fig. 4 shows a soundproofing sleeve (14) with a plurality of parallel grooves (14b) which are cut out on the inside diameter of the soundproofing sleeve (14).

Fig. 5 shows a sound insulation bushing (14) with a swirl groove (14c) cut on the inside diameter.

The sound waves passing through the area of the sound insulation bushing (14) are reflected and absorbed differently in the bores (14a), parallel grooves (14b) or swirl grooves (14c), so that these measures reduce noise.

Another (not shown) embodiment of the soundproofing bushing (14) could be a bushing with a large number of individual recesses of any shape distributed over the inner circumference.

6 shows the area of the tool holder of a rotary hammer (8) with an open holding cap, here referred to as the front cylinder (13), and tool holding bracket (10) without soundproofing measure.

The working principle of the rotary hammers (8) is similar to that of the pneumatic hammers (1). A percussion piston (6) hits the boring bar (9) at the impact surface (7) at high speed, which is guided above the boring bar hexagon in a wear bushing (11). This wear bushing (11) is guided in the drill sleeve (12), which in turn is guided in the front cylinder (13).

Similar to the insertion tool (4) of the pneumatic hammer (1), the boring bar (9) can move freely in its longitudinal axis between the drill retaining bracket (10) and the wear bushing (11). The mobility is limited by the bead between the hexagon (9a) and the boring bar (9).

Fig. 7 shows the hammer drill (8) with soundproofing bushing (14), which, similar to the pneumatic hammer (1), is either inserted between the front cylinder (13) and the wear bushing (11) or releasably attached to the inner wall of the front cylinder (13) is.

Instead of the perforated soundproofing bushing (14, 14a), a parallel grooved soundproofing bushing (14, 14b), a swirl grooved soundproofing bushing (14, 14c) or a bushing with any recesses can be used.

List of reference numbers:

1

Pneumatic hammer / impact tool

2nd

Retaining cap

3rd

Tool holding pawl

4th

Insert tool / chisel

4a

Hexagon

5

Tool holder cylinder

6

Percussion piston

7

Impact area

8th

Hammer drill / drilling tool

9

Boring bar

9a

Hexagon

10th

Tool holder

11

Wear bushing

12

Drill sleeve

13

Front cylinder

14

Soundproofing bush

14a

Breakthroughs / holes

14b

Parallel, radial circumferential grooves

14c

Helical circumferential groove

Claims (4)

Compressed air operated or hydraulically working hammer and drilling tool, so-called compressed air or hydraulic hammer, with a hammer cylinder acting on a plug-in tool by a percussion piston, with an open holding cap for receiving a tool holding pawl, a tool holding bracket or a similar holding element,
characterized,
that between the retaining cap (2) or front cylinder (13) and insertion tool (4, 9) a soundproofing sleeve (14) made of wear-resistant material is arranged, which is releasably attached to the inner wall of the retaining cap (2) or the front cylinder (13) or which is inserted for releasable fastening between the holding cap (2) and the tool holding cylinder (5) or between the front cylinder (13) and the wear bushing (12), that the circumference of the soundproofing bushing (14) has a plurality of openings (14a) or that on the a plurality of recesses is arranged on the inner peripheral surface of the bushings (14). Impact and drilling tool according to claim 1,
characterized,
that the recesses of the sound insulation sleeve (14) have the shape of parallel, radially circumferential grooves (14b). Impact and drilling tool according to claim 1,
characterized,
that the recesses of the soundproofing bushing (14) are arranged in the form of a helical circumferential groove (14c). Impact and drilling tool according to claim 1,
characterized,
that individual recesses of any design are arranged distributed over the inner circumference of the sound insulation sleeve (14).

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