EP0837214A2 - Percussive drill - Google Patents

Abstract

The hammer has a check valve (30) on a base (54) in front of the control housing cover (50). At the bottom of the drill's outer tube (15) is an axially displaceable drill crown (90). This is actuated by a centrally through-bored piston (75) striking its upper surface (89). The piston is guided by a bush (70), which unites with a control housing's lower part (55) and the outer tube. At the upper end of the piston is a cut-off (100), in particular a slide valve. This works in conjunction with a control pin (40). The cut-off has a control bush with radial through holes (101). The bush can be firmly connected to the piston, or is an integral part of it.

Description

The present invention relates to a pneumatically driven hammer drill, especially deep hole hammer, according to the preamble of claim 1.

Conventional drills hammer in valve-controlled intermittent or continuous operation with a drill bit arranged on the foot part, the passages for the Compressed air that is redirected at the bottom of the borehole and kicked off Conveying cuttings upwards. With an in-hole hammer drill e.g. after DE-A-2 705 191 slides a piston in a housing which is inside a External tube is attached, but this can be problematic and prone to failure can. The same applies to so-called valveless rotary hammers.

DE-U-9 202 336 describes a hammer drill of the type mentioned at the outset can also be used in difficult rock. He has for air dosing a rotatably driven tubular body and a slidable one Central passage shaft, the lower end with the tubular body Shut-off device, e.g. forms a slide that creates an air deflection space as required releases or - if necessary partially - closes. However, the neck can the shaft connected to the tubular body and a leading shaft on it Pipe head provided with a number of holes as a result of relative weak cross-sections are at risk of breakage, especially since the length of the hammer drill is included large lever arm attacks it.

It is an important object of the invention to provide a hammer drill of the type mentioned however, without a central tube, so that it can be improved in a simple, economical manner manufacturing construction with a stable piston both its stroke rate and the individual clout also increases. In addition, the hammer drill is said to be large Provide long service life, even with an increased stroke frequency manage with low compressed air consumption and work relatively quietly.

Main features of the invention are in the characterizing part of claim 1 specified. Refinements are the subject of claims 2 to 14.

Starting from a pneumatically driven hammer drill, in particular Deep hole hammer, with a screw cap for connection to a compressed air source and optionally a drill pipe, with one from below into the screw cap protruding check valve, with one held underneath within an outer tube Control device which has a control pin designed as a tubular body has an inner chamber and at least one transverse bore and non-contact in a central bore of a guided in a cylinder liner Percussion piston protrudes, which axially displaces the top surface of the outer tube applied drill bit, the invention provides according Claim 1 before that between the piston-guiding cylinder liner with a Rifle attachment and the outer tube at least partially form-fitting to one Unit is firmly connected, and one above, with the outer tube an annular gap is welded along a circumferentially welded threaded sleeve is present and that the upper end of the percussion piston with the control pin cooperating shut-off forms, in particular a slide valve.

This extremely simple construction ensures through its control, that there is always under air on the drill bit side, so that the starting process and the Piston return stroke takes place automatically and therefore the hammer even under difficult external conditions start reliably. Those coming from above and below Air flows are directed against and past each other. At the tapered end of the control pin can be a diameter step the air flow Significant support in the inlet area of the percussion piston central bore. By having a shut-off device at the upper end of the percussion piston is, namely a slide valve interacting with the control pin, reliable air control is achieved in a particularly simple manner.

Appropriately, the control pin according to claim 2 has a tubular body upwards with a perforated flange or disc head on one axial and / or radially projecting collar within the threaded sleeve and after supported at the bottom on a sleeve that delimits the annular gap on the inside. This clear Construction ensures safe control even under unfavorable conditions Operating conditions.

The development of claim 3, according to which the check valve is advantageous, is structurally advantageous is carried by a cover plate which is attached to the screw cap connects and passages close to the circumference as well as one protruding downwards Bund has. This arrangement is extremely simple and stable; it ensures always good air supply. According to claim 4, this is supported by a convex Curving of the control pin plate head, especially with rounded transitions to the circumferential passages and / or to the inner chamber.

A particularly reliable construction results according to claim 5 by the Sleeve is formed hat-shaped and with a lower bounding the annular gap below Collar, flange or the like is supported on a rifle attachment on the Cylinder liner sits and on its upper part axially parallel to the outer tube Has recesses. This ensures a stable attachment still leaves room for small movements of the control pin, e.g. at operational vibrations. This is further promoted by the measure of claim 6, after which between the plate head and the sleeve Sealing ring and / or between the sleeve and the sleeve top part flexible ring is arranged to compensate for a certain position and tolerance to achieve. By further according to claim 7, the cylinder liner and the Rifle top part are designed as finned tubes with the same profile, results there is also a large-volume channeled air duct in the lower hammer area.

On the control pin slides according to claim 8 with the percussion piston connected control socket, which is provided with radial openings. This allows a particularly fast reversal of the air flows. It is cheap if according to claim 9 of the control pin in the area of the radial outlets has a circumferential recess with an upper and a lower control edge. This contributes significantly to precise reversal with minimal component effort at.

Advantageously, the control bush according to claim 10 has such an axial length that the circumferential recess of the Control pin and its cross holes closed. With the drill bit pressed the hammer drill therefore starts up easily; at the same time the Compression chamber vented above the percussion piston.

In claim 11 it is provided that between the inner chamber and one of the Cylinder liner delimited a flow connection in compression chamber upper positions of the percussion piston can be produced and in lower positions can be closed, in particular by means of the circumferential recess via the transverse bores and the radial passages, which as bores or slit-shaped can be trained. The percussion piston itself causes the reversal its movement in a very simple way.

Another development of the invention according to claim 12 is that the Inner chamber of the control pin receives an insert and with one in it preferably centrally arranged channel flow-connected or connectable is. This makes it possible to flow through a constant amount of air to let. This is particularly advantageous in difficult rock conditions.

According to claim 13 is in the area of the control pin, in particular between the Inner chamber and the channel of the insert, a flow restrictor attached or attachable, according to claim 14, a lockable or screwable plug can be with or without passage. So in particular with different large bores equipped flow restrictors selected and used in order to take account of the air requirements caused by local conditions to wear.

Fig. 1

eine Längsschnittansicht eines erfindungsgemäßen Bohrhammers,

Fig. 2

eine Seitenansicht, teilweise im Längsschnitt, eines Schlagkolbens,

Fig. 3

eine vergrößerte Teil-Längsschnittansicht zu Fig. 1 (seitenverkehrt),

Fig. 4

eine Draufsicht auf eine Deckelplatte,

Fig. 5

einen Längsschnitt der Deckelplatte von Fig. 4 (entsprechend der Linie V-V) sowie eines Steuerzapfen-Tellerkopfes, und

Fig. 6

eine Seitenansicht, teilweise im Axialschnitt, einer Zylinderbüchse mit Büchsenaufsatz.

Further features, details and advantages of the invention result from the wording of the claims and from the following explanation of exemplary embodiments with reference to the drawing. In it show:

Fig. 1

2 shows a longitudinal sectional view of a hammer drill according to the invention,

Fig. 2

a side view, partially in longitudinal section, of a percussion piston,

Fig. 3

2 shows an enlarged partial longitudinal sectional view of FIG. 1 (reversed),

Fig. 4

a plan view of a cover plate,

Fig. 5

a longitudinal section of the cover plate of Fig. 4 (according to the line VV) and a control pin disc head, and

Fig. 6

a side view, partially in axial section, of a cylinder liner with a sleeve attachment.

A hammer drill, generally designated 10, has, as can be seen from FIG. 1, a screw cap 11 with a central passage 12 and a threaded connection 13, with the interposition of a sealing ring 14 for connection of the main hammer body is used. A strainer 16 is in the Screw cap 11 which can be screwed to a threaded bushing 50. This is welded to an outer tube 15 along a cylindrical welding zone S. An annular gap 54 is between the outer tube 15 and a cylinder liner 70 formed, which leads a percussion piston 75. The outer tube 15 has - starting at the lower area of welding zone S and threaded bush 50 - over the Scope distributed longitudinal longitudinal grooves 17, the approach of a Serve tool when screwing to the cap 11.

The screw cap 11 encloses an upward check valve 30, which is guided on a shaft 28 and the valve spring 29 there to a valve seat 18 charged. Bottom side engages in the screw cap 11 within the Threaded sleeve 50 a cover plate 26, which preferably with the circumference axially extending passages 24 is provided, e.g. with a wreath of four Arch slits (Fig. 4). An adjoining control pin 40 takes one preferably tapered insert 45 and projects into a central bore without contact 82 of the percussion piston 75 guided in the cylinder liner 70, even if this is in its lowest position (left in Fig. 1). The use 45 of the Control pin 40 runs narrow from a diameter step 46 and has in particular an inner channel 105 in the center.

The threaded bushing 50 delimits a distribution chamber below the screw cap 11 56, which is fluidly connected to an inner chamber 42 of the control pin 40 is. A control bushing 100 of the percussion piston 75 slides on the latter Slider valve through which the stroke air can be controlled. Preferably, the closes Control pin 40 having an upwardly convex flange or plate head 41 e.g. has twelve passages 48, directly on the flat or concave cover plate 26, which is axially and / or radially projecting on the circumference Bund 52 can have. The plate head 41 has a groove receptacle on its underside for a sealing ring 53 to which the inner circumference of a sleeve 51 connects. This holds the plate head 41 and delimits the inside between the outer tube 15 and an upper sleeve part 55 an annular gap 54, which together with a radial gap 22 an upper chamber of relatively large volume forms.

Another volume reservoir is underneath in the form of the outer axial channels 60 of rifle top part 55 and cylinder liner 70 available up to to passages 72 and a circumferential groove 61. The cylinder liner 70 has outer ribs 71, between which the air-guiding outer channels or Longitudinal slots 60 are distributed over the circumference (Fig. 6). The latter sit down the with the cylinder liner 70 profile top sleeve 55, the with a collar 57 at the transition to the lower part 58 on the upper edge of the cylinder liner 70 sits and on which the sleeve 51 or the like with a flange 62. under Intermediate layer of a flexible ring 64 supports (Fig. 3). The lower part of the rifle attachment 58 is rotationally fixed to the cylinder liner 70 by at least one pin 59 connected.

The control pin 40 has the shape of a tubular body. Its arched upwards Flange, plate head 41 or the like externally directed passages 48 provided the wreath of arch slots 24 of the cover plate 26 face upwards (FIGS. 4 and 5). At a paragraph 47 the plate head 41 has a circumferential groove 43 for receiving a sealing ring 53 the inner chamber 42 lead transverse or reversing bores 44 over a Circumferential recess 102 in the surrounding space. This represents in the raised position of the piston 75 is a compression chamber 83.

The lower end of the piston 75 is with a valve surface 79 on a foot valve 97 slidable, which sits in the head 91 of a drill bit 90. It has a central one Passage 92 and is held in a retaining cap 93, which after insertion of Head 91 and shaft 95 with the interposition of a buffer sleeve 85 and one Retaining rings 86 is screwed into the outer tube 15. A shoulder 88 of the retaining ring 86 comes to a stop on the head 91 of the drill bit 90 when the percussion piston 75 hits their impact surface 89 with his punch. Fig. 1 also shows 3 shows two different working positions of the rotary hammer 10. The percussion piston can be seen in the right half of FIG. 3 75 in its impact position, in which its lower end on the surface 89 of the Drill bit 90 opens or is opened.

The structure of the percussion piston 75 is shown in FIG. 2. It is generally cylindrical and has transverse grooves 77 on the outside and an outer groove approximately in its longitudinal center Annular groove 76, which defines an upper control edge 80 and a lower control edge 81. These edges guide the opening and closing of the air flow Passages 72 at the lower end of a groove-shaped annular chamber 76 (FIG. 1). Distributed over the circumference, axial bores go from the annular groove 76 open to the outside 78 to the bottom of the piston 75. Its central bore 82 can beveled at the lower end and forms a valve surface immediately above 79 with the foot valve 97 when sliding on this in the lower piston position cooperates. It can be seen that the percussion piston 75 in its upper part massive, not weakened by axial holes, so that the head surface 74 together with that of an attached control bush 100 fully for the working pressure is available. The control bushing 100 is made of tough plastic, e.g. an acetal resin such as Delrin (= POM, polyoxymethylene). It is over a connection 103 firmly connected to the upper end of the percussion piston 75 and on the control pin 40 slidably. Together with the latter she imagines Slider valve through which the stroke air can be controlled.

The control pin 40 has an outer circumferential recess 102 with an upper one Control edge 106 and a lower control edge 107. In the area between the Control edges 106, 107 of the control pin 40 have radial outlets leading to the outside 101 and / or transverse bores 44 (FIGS. 1 and 3), which also have elongated holes or longitudinal slots (Fig. 2) and with the compression chamber 83 in constant flow connection.

The axial length of the control bush 100 is dimensioned so that it is in the deepest Position of the percussion piston 75 (right in Fig. 3), the cross bores 44 of the Control pin 40 still closes. The percussion piston 75 moves on the return stroke high (left in Fig. 3), so the upper end of the control bushing 100 comes from below in a sleeve attachment 55/58, the control pin 40 in concentric Distance surrounds and down with a shoulder or flange 62 below Intermediate layer of a flexible ring 64 on a collar 57 of the cylinder liner 70 is supported. The upper control edge 106 of the passage 101 passes over the Control edge 107 of the recess 102 of the control pin 40, so the Cross bores 44 released and the compression chamber 83 begins to fill with stroke air via passages 44, 101, 102. With another Upward movement of the percussion piston 75 is only the upper control edge 106 of the Recess 102 and then closed the transverse bore 44, whereby the im compression chamber 83 becoming smaller and smaller increases.

As soon as top dead center is reached, the stroke of the piston 75 begins. If the lower edge 107 of the passage 101 is the control edge 106 of the Recess 102 passes over and thereby cross holes 44 of the control pin 40 releases again, the percussion piston 75 is accelerated. The full one Pressure on the entire face of the control bush 100 and piston 75, so that these elements are moving downwards together faster and faster Piston 75 strikes the head surface 89 of the drill bit 90 (FIG. 3, right).

The tubular control pin 40 goes on a diameter step 46 in the tapered insert 45 over that through the axial channel 105 to the inner chamber 42 is flow connected or connectable and as a flow restrictor or can act as a closure. Depending on the air requirement, inserts can 45 with different sized bores or without a passage (see Fig. 1 and 3) can be used to ensure that drilling operations are carried out in the best possible To adapt conditions.

The invention is not restricted to the exemplary embodiments described, but can be modified in many ways. So you can easily between the screw cap 11 and the threaded bush 50 an adapter and / or a so-called. Install the turbo attachment as described in detail in DE-U-9 202 336. To can sit a sleeve between the connection cap 11 and an adapter, the Outer diameter is equal to that of the outer tube 15; she is with the Adapter directly or via a sliding piece including a short one guided in it Profile shaft drive-connectable. An additional, mechanical one is achieved Protected control option for airflow division, whereby on the one hand Central air brought into the drill bit 90 and on the other hand blown air as required is branched off.

It can be seen that the pneumatically driven hammer drill 10 according to the invention has a connection cap 11 for a compressed air source and an outer tube 15, which is firmly connected to a threaded bushing 50. On a top part of a rifle 55 sits as a tubular body with an inner chamber 42, outer peripheral recess 102 and transverse bores 44 trained control pin 40, the has an insert 45 below and contactlessly in a central bore 82 Percussion piston 75 protrudes. This is massive at the top; to its externally open annular groove 76 - which need not be semi-oval, but e.g. as indicated by dashed lines in FIG. 2 can also have a semicircular cross section - close down axial bores 78 in an annular space 94 surrounding the drill bit head 91 flow out. The percussion piston 75 slides on a foot valve 97, which in a Cylinder liner 70 is guided, which also has the upper part of the bushing with outer ribs 55 and the outer tube 15 at least partially positively firmly connected to a unit e.g. has shrunk.

The control bush 100 is axially long enough to be in the impact position of the Percussion piston 75 closes the cross bores 44 of the control pin 40. in the In the lower area it has radial passages 101, which are e.g. can be formed at 60 ° circumferential intervals (Fig. 2). The outer Circumferential recess 102 of the control pin 40 has control edges 106 or 107, in order - in particular through the circumferential recess 102, the transverse bores 44 and the radial passages 101 - between the inner chamber 42 and a compression chamber 83 delimited by the cylinder liner 70 To establish flow connection in the upper positions of the percussion piston 75 and to close in lower positions. The inner chamber 42 of the control pin 40 is fluidly connectable to an insert channel 105. A latched or screwable sealing plug and / or flow limiter influences the Air control. When using a passage-free closure insert 45 the hammer drill 10 works without additional blowing air.

All arising from the claims, the description and the drawing Features and benefits, including design details, spatial Arrangements can be made both individually and in any combination be essential to the invention.

Reference list

S

Welding zone

10th

Hammer drill

11

Screw cap

12th

Passage

13

Thread (connection)

14

Sealing ring

15

Outer tube

16

Sieve insert

17th

External grooves

18th

Valve seat

22

radial gap

24th

Axial diffusers

26

Cover plate

28

shaft

29

Valve spring

30th

check valve

40

Control pin

41

Plate head

42

Inner chamber

43

Circumferential groove

44

Cross hole (s)

45

commitment

46

Diameter step

47

paragraph

48

(oblique) passages

50

Threaded sleeve

51

Sleeve

52

Federation

53

Sealing ring

54

Annular gap

55

Rifle attachment lower part

56

Distribution chamber

57

Federation

58

Rifle attachment lower part

59

pen

60

Longitudinal slots / outer channels

61

Circulation groove

62

flange

64

flexible ring

70

Cylinder liner

71

Ribs

72

Culverts

73

Fitting groove

74

Head area

75

piston

76

Ring groove

77

(Cross) grooves

78

Axial bores

79

Valve surface

80

upper control edge

81

lower control edge

82

Central bore

83

Compression chamber

85

Buffer sleeve

86

Retaining ring

88

shoulder

89

Impact area

90

Core bit

91

head

92

Passage

93

Retaining cap

94

Annulus

95

shaft

97

Foot valve

100

Control socket

101

Radial diffusers

102

Circumferential recess

103

Piston connection

105

(Blown air) channel

106

upper control edge

107

lower control edge

Claims (14)

Pneumatically driven hammer drill, in particular deep hole hammer (10), with a screw cap (11) for connection to a compressed air source and optionally a drill pipe, with a check valve (30) projecting from below into the screw cap (11), with one underneath within an outer tube (15 ) held control device, which has a control pin (40) designed as a tubular body, which has an inner chamber (42) and at least one transverse bore (44) and projects contactlessly into a central bore (82) of a percussion piston guided in a cylinder liner (70), which piston Top surface (89) of a drill bit (90) held axially displaceably on the outer tube (15) at the bottom, characterized in that between the piston-guiding cylinder sleeve (70), which has a sleeve attachment (55, 58) and the outer tube (15), is at least partially positively closed a unit is firmly connected, and one above it, with the outer tube (15) along a path Ice zone (S) circumferentially welded threaded bushing (50) there is an annular gap (54) and that the upper end of the percussion piston (75) forms a shut-off element which cooperates with the control pin (40), in particular a slide valve. Hammer drill according to claim 1, characterized in that the control pin (40) designed as a tubular body has a disc head (41) which is provided with passages (48) close to the circumference and which is directed upwards on an axially and / or radially projecting collar (52) within the threaded bushing (50) and supported downwards on a sleeve (51) which delimits the annular gap (54) on the inside. Hammer drill according to claim 1 or 2, characterized in that the check valve (30) is carried by a cover plate (26) which connects to the screw cap (11) and has passages (24) close to the circumference and a collar (52) projecting downwards. Hammer drill according to claim 3, characterized in that the plate head (41) of the control pin (40) is convexly curved, in particular with rounded transitions to passages (48) close to the circumference and / or to the inner chamber (42). Hammer drill according to one of claims 2 to 4, characterized in that the sleeve (51) is hat-shaped and with a collar, flange (62) or the like which delimits the annular gap (54) at the bottom. is supported on a sleeve attachment (55; 58) which sits on the cylinder sleeve (70) and has recesses (60) which are axially parallel to the outer tube (15) on its upper part (55). Hammer drill according to Claim 5, characterized in that a sealing ring (53) and / or a flexible ring (64) is arranged between the plate head (41) and the sleeve (51) and / or between the sleeve (51) and the upper part of the sleeve attachment (55) is. Rotary hammer according to claim 5 or 6, characterized in that the cylinder liner (70) and the upper part of the liner attachment (55) are designed as finned tubes of the same profile. Hammer drill according to one of claims 1 to 7, characterized in that the shut-off device has a control bushing (100) which is provided with radial passages (101) and which is fixedly connected to the percussion piston (75) or in one piece. Hammer drill according to claim 8, characterized in that the control pin (40) has in the region of the radial passages (101) on the outside a circumferential recess (102) with an upper and a lower control edge (106 and 107). Hammer drill according to claim 9, characterized by such an axial length of the control bushing (100) that in the impact position (on the right in FIG. 3) of the percussion piston (75) the outer circumferential recess (102) and the transverse bores (44) of the control pin (40 ) closes. Hammer drill according to one of claims 1 to 10, characterized in that between the inner chamber (42) and a compression chamber (83) delimited by the cylinder liner (70) - in particular through the circumferential recess (102) via the transverse bores (44) and the Radial passages (101) - a flow connection can be established in the upper positions of the percussion piston (75) and can be closed in lower positions. Hammer drill according to one of claims 1 to 11, characterized in that the inner chamber (42) of the control pin (40) receives an insert (45) and is flow-connected or connectable to a channel (105) preferably arranged centrally therein. Rotary hammer according to claim 12, characterized in that a flow limiter is attached or attachable in the area of the control pin (40), in particular between the inner chamber (42) and the channel (105) of the insert (45). Hammer drill according to claim 13, characterized in that the flow limiter is a lockable or screwable plug with or without a passage.

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