EP0326138B1 - Device for decoring castings - Google Patents

Abstract

The invention relates to a device for removing internal cores from castings after the solidification of the cast metal, using a rapping mechanism which has two pillars (3 and 4) arranged vertically, at a distance from and parallel to one another, a horizontally aligned rapping hammer (20) being arranged on one pillar (4) and a buffer (23) being arranged on the other pillar (3). <IMAGE>

Description

The invention relates to a device for a tapping device according to the preamble of claim 1. Such a device is used to remove inner cores from castings after the casting metal has hardened.

A device for removing inner cores from castings after hardening of the cast metal has been proposed, which has a knocking table over which a jackhammer with a plunger is arranged. The casting is placed on the tapping table and held. Then a predetermined impact or knocking energy is applied to the back wall of the casting with the plunger of the pneumatic hammer. The impulses of the knock energy are transmitted through the wall of the casting to the core, which adheres to the inner wall of the casting, and produce cracks in the core, so that the core is broken down into several sections. At the same time, however, because of the different natural resonance of the casting and the core, the core material is detached from the inner wall of the casting, with abrasion (loose molding sand) being formed.

From DE-OS 32 19 390 a device for removing the core sand from castings is known, the casting being clamped between a vibrator and an adjustable support. The vibrator is a pneumatic hammer, which is located on a frame support of the device via a shock and vibration-damping intermediate layer supports stationary. The hammer tip of the pneumatic hammer forms a clamping unit for the casting with an anvil supported on the frame support by means of a further shock and vibration-absorbing intermediate layer. In this known device, two or more hammer devices can also be arranged side by side on the same machine frame for processing the same casting by all hammer devices or several castings by one hammer device at a time. However, the possibilities for arranging several hammer devices are limited in space.

A device of the type mentioned in the preamble of claim 1 is known from GB-A-2 063 739. In this known device, the holder for the knocking hammer is mounted relative to the material to be knocked back and forth on a holder which is in turn pivotably mounted. A disadvantage of this device is that it requires a relatively large amount of space. This also applies to the device, which is also designed in accordance with the features of the preamble of claim 1 and is known from US-A-1 768 428, in which a piston acting on the holder for the knocking hammer of a hydraulic cylinder / piston device for the relative movement of the holder carrying the tapping hammer is provided relative to the casting.

The object of the present invention is to design a device of the type specified in the preamble of claim 1 with a compact structure with respect to the material to be tapped adjustable.

This object is solved by the features of claim 1. Advantageous developments of the invention are characterized in the subclaims.

Fig. 1

eine Frontansicht der Klopfvorrichtung;

Fig. 2

eine Seitenansicht der Klopfvorrichtung;

Fig. 3

eine Draufsicht auf die Klopfvorrichtung;

Fig. 4.

einen Klopfhammer-Halter im Längsschnitt;

Fig. 5.

den Halter gemäß Fig. 4 in ausgefahrener Stellung des Klopfhammers;

Fig. 6

einen Klopfhammer-Halter im Längsschnitt als zweites Ausführungsbeispiel;

Fig. 7

den Halter in der Seitenansicht von rechts;

Fig. 8

den Halter im Schnitt VIII-VIII in Fig. 7 in ausgefahrener Stellung des Klopfhammers.

The invention is explained below on the basis of preferred exemplary embodiments illustrated in a drawing. Show it:

Fig. 1

a front view of the tapping device;

Fig. 2

a side view of the tapping device;

Fig. 3

a plan view of the tapping device;

Fig. 4.

a tapping hammer holder in longitudinal section;

Fig. 5.

4 in the extended position of the tapping hammer;

Fig. 6

a knocking hammer holder in longitudinal section as a second embodiment;

Fig. 7

the holder in a side view from the right;

Fig. 8

the holder in section VIII-VIII in Fig. 7 in the extended position of the tapping hammer.

The tapping device has two foot beams 1, 2 which are spaced apart and parallel to one another and rest on the floor. An upright column 3, 4 is arranged in the longitudinal center of the foot beams. The columns 3, 4 are firmly connected to one another at the top via a cross member 5. Parallel to the cross member 5, a cross member 6 is arranged between the foot beams 1, 2.

Adjacent to the column 4, a frame 7 is provided on the floor parallel to the foot beam 2 and is approximately half the height of the columns 3, 4. The frame 7 carries two spaced rails 8, 9 which are parallel to the Foot bars 1, 2 run and are about as long as the foot bars. Connection rails 11 are located in front of an opening 12 of the cabin 10, in which the knocking device is preferably housed. On the rails 8, 9, a carriage 13 is placed, which carries a casting 14.

The carriage 13 has a chassis 15. The chassis 15 has a front axle 16 and a rear axle 17, each of which has two wheels 18 which are guided on the rails 8, 9. In the interior of the chassis 15 a bearing plate 19 is arranged, under which rollers 20a rotating about axes 21a extending transversely to the axes 16, 17 are arranged in the corner regions of the bearing plate 19, which roll on the axes 16, 17, so that the bearing plate 19 transversely to the direction of the rails 8, 9 is displaceably mounted on the chassis 15. Two rollers 20a, which are arranged one above the other and spaced apart from one another, are preferably provided, which grip around the respective axis 16 or 17 from above and below and are guided in a rail-like manner.

With this construction, the bearing plate 19 can be moved in the direction of the axes 16, 17. With suitable locking means (not shown), the carriage 13 can be locked on the rails 8, 9 and the bearing plate 19 in the central position between the axes 16, 17.

According to the invention, a holder 20 for a horizontally extending knocking hammer, in the present embodiment a pneumatic hammer 21, is arranged on the column 3, approximately halfway up and adjustable in height, which can be moved against the casting 14. Opposite the pneumatic hammer 21, an elastic buffer 23 is arranged on the column 4 in a height-adjustable manner. If the pneumatic hammer 21 is extended and the locking of the rollers 20a is released, the tappet 21.1 of the pneumatic hammer 21 presses the casting 14 against the buffer 23. The tappet 21.1 can then be set into oscillating tapping movements so that the required tapping energy is transferred to the casting can. After knocking has been completed, the knocking hammer 21 is moved back, the bearing plate 19 is brought into its starting position and the carriage 13 can then be moved out of the cabin 10.

For special tapping on the casting, e.g. in the case of castings with inclined outer surfaces, it is advantageous to hold the pneumatic hammer 21 in such a way that it can be aligned essentially at right angles to the surface of the casting to be acted upon and, if necessary, can be locked in this position. This can be achieved in that the holder 20 is horizontally and parallel to the frame 7 or the rails 8, 9 adjustable and horizontally and vertically or articulated, preferably mounted on the column 3.

According to a special embodiment of the invention, a piston cylinder arrangement 24 is located in the area of the frame 7 Axle 17 is arranged under the carriage 13 of a carriage located in the cabin 10, the piston rod 25 of which can raise the carriage in the region of the axis 17 when it is extended, so that the carriage is pivoted upward about the axis 16. By quickly pulling back the piston rod 25, the car suddenly falls back onto the rails 7, 8, resulting in an impact energy which is transmitted to the casting which is on the car. This impact energy complements the destruction of the inner core of the casting.

A first particularly expedient embodiment of a holder 20 is shown in FIGS. 4 and 5.

The holder 20 has a hollow cylinder 28 in which a piston 29 is guided. The piston 29 is hollow-cylindrical and is connected at the front to a hollow-cylindrical piston rod 40 which has a smaller diameter than the inside diameter of the hollow cylinder, so that a cylinder annular space 41 remains. At the rear, the piston 29 has a solid piston rod 38. The piston rod 38 is designed as a separate part and is screwed into an internal thread of the piston 29, the extension 37 of the piston rod 38 carrying the external thread 42 also being hollow cylindrical. Immediately behind the thread 42 is an outwardly projecting ring step on the piston rod 38. On the piston 29, on the piston rod 38 or on the ring step 31, a sealing ring 32 is arranged in a corresponding groove 33, which abuts the inner cylinder surface 34 of the hollow cylinder 28. The annular step 31 forms a front annular surface 35, which rests against the end surface of the hollow cylinder 29, and a radially deeper rear annular piston surface 36.

The rear annular piston surface 36 is engaged behind by a radially aligned ring step 30, which is seated on the piston rod 38 and is arranged in the hollow cylinder 28 immediately behind the ring step 30 a sealing ring 39 is seated in a corresponding ring insert 43.

The piston rod 38 closes the cylinder 28 to the rear. A radially aligned bore 44 at the free end of the piston rod 38 merges into an axially aligned bore 45, which opens into the interior 46, 46.1 of the piston 29 or the piston rod 28. A pressure medium can be conducted into the interior 46.1 of the piston rod 38 through the bores 44 and 45. A connecting element 47, e.g. a pressure medium hose is inserted, which passes through an axially parallel, slot-shaped recess 47.1 in the cylinder 28, which extends approximately to the sealing ring 39.

The hollow cylindrical piston rod 40 is mounted in a form-fitting manner in a cylinder cover ring 48 which sits on the cylinder 28 and in a ring groove 49 supports a sealing ring 50 which is seated on the outer circumferential surface of the piston rod 40. In the annular space 41, a pressure medium acting on the piston surface 53 or 36, here compressed air, can be given through a bore 51 or 52, so that the piston 29 can be moved with the piston rods 40 and 38 in the cylinder 28 until it hits the cylinder cover ring 48 or the ring step 30 bumps. In the interior 46, 46.1 of the piston 29 or the piston rod 38, the pneumatic hammer 21 is mounted in a manner known per se with a flange-shaped ring step 54, which can be moved longitudinally slightly, the stroke of which is forward through a stroke-limiting surface 55 in the piston 29 and rearward through that from the front end the piston rod 38 formed stroke limiting surface 56 is limited in the interior 46.

On the back of the pneumatic hammer 21 or on the ring step 54, an extension 57 is arranged coaxially, in which the control for the action of the plunger 21.1 causing an oscillating movement or impact movement of the plunger 21.1 is accommodated in a manner not shown. Between At the rear end of the extension 57 and the base 65 of the interior 46.1, a buffer 66 is arranged in a disk made of rubber or elastic plastic, which can be attached to the extension 57 or the base 65.

The pressure medium introduced into the inner space 46 via the bore 44, 45 acts against a double-acting piston (not shown) in the pneumatic hammer 21 and drives it forward, the piston striking the striking surface of the plunger 21.1. The pressure medium then acts on the other piston surface and drives the piston back until it is reversed again by a slide, in particular a pipe slide. The control or deflection of the air is ensured in a manner known per se by the pipe slide which can be moved back and forth, corresponding air channels (not shown) being provided which lead to the cylinder chamber of the pneumatic hammer 21. The rebound or kickback energy or the impacts transmitted from the tappet 21.1 to the piston 29 are partially destroyed or buffered by an elastic buffer 58, which is located in front of the ring stage 54 and is supported against the ring stage formed by the stroke limiting surface 55, and steamed.

The guide shaft 60 of the pneumatic hammer 21 protrudes centrally from the mouth 59 of the cylinder 28, wherein it has a smaller diameter than the inside diameter of the cylindrical piston rod 40 and the mouth 59. A radially aligned support ring 61 arranged in the mouth region supports the guide shaft 60 in a radially positive manner. The rear support of the guide shaft 61 takes over the ring step 54.

The exhaust air from the pneumatic hammer 21 flows through radial channels 67 into the annular space 68 between the piston rod 40 and the guide shaft 60 and from there through axial channels 69 in the support ring 61 to the front.

5 shows the piston 29 extended to the front stop 62 on the cylinder cover ring. Between these two positions shown, the piston 29 can assume any intermediate position. The respective intermediate position can be locked with suitable means. In the respective position of the piston 29, the oscillating movement can then be transmitted to the plunger 21.1, which should act on the casting as knocking energy.

In the exemplary embodiment according to FIGS. 6 to 8, the pneumatic hammer 21 is mounted in a piston 72 which has a piston rod 73 only at the front, so that the rear working chamber 74 of the working cylinder 75 can be delimited by a closed rear end wall 76. As a result, not only is a shorter design specified, but also better protection for the piston 72, both with regard to dirt and damage due to impact or impact.

The loading channel 77 for the preferably pneumatic pressure medium for loading the plunger 21.1 extends to the outer surface of the piston 72 and is connected here to a recess, preferably an annular recess 78, in the outer surface of the piston 72. The length 1 of the ring recess 78 corresponds to the stroke length H that the piston 72 is able to carry out.

The length L of the piston 72 is greater than the stroke length H, so that there is sufficient space for sealing rings between the ring recess 78 and the ends of the piston 72, two sealing rings 81, 81 'being arranged next to one another on each side, one at a time To ensure sealing between the ring recess 78 and the front and rear working chamber 82, 74 of the working cylinder 75. In the peripheral wall 84 of the working cylinder 75 there is a radial connection hole 85 for an admission line, not shown so arranged that it communicates with the ring recess 78 in each position of the piston 72. In this embodiment, an actuation line which is stationary with respect to the working cylinder 75 and which acts on the pneumatic hammer 21 can thus be realized, which is essentially designed as in the first exemplary embodiment according to FIGS. 4 and 5.

The interior 46.1 on the rear of the annular step 54 of the pneumatic hammer 21 is delimited on the rear by a cup-shaped insert 92, preferably screwed into a recess in the piston 72 on the rear, with a cylindrical cavity 93 forming the interior 46.1, into which the extension 57 is immersed. The buffer 66 lies here on the base 65 of the recess in the insert part 92.

In the present exemplary embodiment, the length e of the piston rod 73 of the piston 72 is dimensioned so large that, in the rear position of the piston 72 shown in FIG. 6, the piston rod 73 protrudes by the dimension f from the front end of the working cylinder 75. In this protruding area, a radial opening 106 is provided in the hollow cylindrical peripheral wall of the piston rod 73, through which the annular cavity 108 located between the peripheral wall and the guide shaft is ventilated. This results in a low-noise exhaust outlet. It is also possible to discharge the exhaust air to the outside atmosphere by connecting the opening 106 to a flexible line. As in the first embodiment, in this embodiment the piston 72 is pushed so far during operation that the plunger 21.1 reaches the workpiece to be loaded, in particular a casting, and then the compressed air is applied to it.

The targeted advancement and retraction of the piston 72 takes place by acting on the working chambers 82, 74 of the working cylinder 75 by means of a pneumatic or hydraulic medium, which is not shown, at connection openings 109, 111 connectable lines to the working chambers 82, 74 can be fed and removed again. In the present exemplary embodiment, the connection opening 109 associated with the rear working chamber 74 is located on the circumference of the rear end wall 76 of the working cylinder 75, and is connected to the rear working chamber 74 by a radial and axial channel 110. The connection opening 111 belonging to the front working chamber 82 is located in the peripheral wall 84 of the working cylinder 75, adjacent to the existing front end wall 112, which radially supports and guides the piston rod 73 in a guide bore 113, with a sealing ring 114 in a groove in the guide bore 113 is arranged to seal the front working chamber 82.

A guide bore 115 in the end wall 116 of the piston rod 73 is used for radial support of the front end of the pneumatic hammer 21 or guide shaft 60, in which the cylindrical piston rod 73 is supported radially and is guided longitudinally.

For the intermittent action on the plunger 21.1 of the pneumatic hammer 21 according to the first and second exemplary embodiments, the existing pressure generating device for the pneumatic pressure medium and a rivet hammer control known per se, which is preferably assigned to the pneumatic hammer 21 in the attachment 57, are used.

As can be seen in particular from FIG. 7, the jacket section of the working cylinder 75 has a square, preferably square, outer cross section, in which the round inner cross section extends. As a result, not only is the stability of the working cylinder 75 increased, but it is also advantageously possible to arrange four fastening screws 117, 118 for the end walls 76, 112 which axially surround the peripheral wall 84 in the region of the corners of the square cross section.

In practice, different amounts of mass are often required for castings to be treated, e.g. for castings of different types or different materials. For this purpose, it is advantageous to assign two or more pneumatic hammers 21 of different weight or different mass to the knocking hammer 20 as replacement parts. By installing the predetermined pneumatic hammer 21, the knocking performance can thus be adjusted.

Claims (18)

1. Device for a rapping device with a rapping hammer (21), more particularly a compressed air hammer, which is mounted on a holder (20) such that it moves forwards and backwards with respect to a product to be rapped, characterised in that the holder (20) has a hollow cylinder (28,84) in which a piston (29) is guided, which carries the rear end of the rapping hammer (21) and which is movable when driven pneumatically in the hollow cylinder (28,84) for driving the rapping hammer (21) forward and backwards against the product to be rapped, and in that the piston (29) is hollow and receives the rapping hammer in its interior space (46).
2. Device according to Claim 1, characterised in that the piston (29,72) is a hollow cylinder and at the front end is joined to a hollow cylindrical piston rod (40,73) which has a smaller diameter than the inside diameter of the hollow cylinder (28,84) so that a cylindrical annulus (41) is left and that preferably at the rear end the piston (29) is provided with a heavy piston rod (38).
3. Device according to Claim 2, characterised in that the piston rod (38) is formed as a separate part and is screwed into an internal thread of the piston (29), in which an external thread (42) is on an extension piece (37) of the piston rod (38) and which is also a hollow cylinder.
4. Device according to Claim 3, characterised in that immediately behind the thread (42) an annular step (31) projecting outwards is provided on the piston rod (38) and has a sealing ring (32) in a corresponding groove (33), wherein the sealing ring (32) rests against the inside cylindrical surface (34) of the hollow cylinder (28) and the annular step (31) forms a front annular edge (35) resting against the end edge of the hollow cylinder (29) and a radially lower, rear annular edge (36).
5. Device according to Claim 4, characterised in that the rear annular edge (36) is gripped rearwards by a radially aligned annular step (30) situated in the hollow cylinder (28) and resting on the piston rod (38), wherein a sealing ring (39) sits in a corresponding annular groove (43) immediately behind the annular step (30).
6. Device according to Claim 5, characterised in that the piston rod (38) shuts off the cylinder (28) rearwards and at the free and has a radially aligned bore (44) which passes into an axially aligned bore, opening into the interior space (46) of the piston (29), and that in the region of the bore (44) a slot-shaped recess (47.1) is situated in the cylinder (28) extending approximately up to the sealing ring (39).
7. Device according to Claim 6, characterised in that the hollow cylindrical piston rod (40,73) is mounted to lock positively in a cylinder cover ring (48,112) which sits on the cylinder (28,84).
8. Device according to Claim 7, characterised in that the cylindrical cover ring (48,112) is mounted in an annular groove (49) of a sealing ring (50,114), which sits on the outside shell surface of the piston rod (40,73).
9. Device according to one or more of Claim 1 to 8, characterised in that the bores (51 and/or 52) open into the annular space (41).
10. Device according to one or more of Claims 1 to 9, characterised in that the compressed air hammer (21) having an annular step (54) is mounted in the interior space (46) of the piston (29,72) to which annular step a forwards stroke limiting surface (55) and a rearwards stroke limiting surface (56,67) are arranged in the interior space (46) and that buffers (58,66) are provided between the limiting surfaces (55,56 and/or 67) and the compressed air hammer (21).
11. Device according to one or more of Claims 1 to 10, characterised in that the compressed air hammer (21) projects centrally from the mouth (59) of the cylinder (28,84), in which the guide shaft (60) has a smaller diameter than the inside diameter of the cylindrical piston rod (40,73) and the mouth (59), and that a radially aligned supporting ring (61,116) supports the guide shaft (60) so that it locks positively, so that the rear support of the guide shaft (60) receives the annular step (54).
12. Device according to Claim 11, characterised in that the piston (72) is a piston provided on one side with a piston rod (73), wherein the piston rod (73) extends forwards from the piston (72).
13. Device according to Claim 12, characterised in that the piston rod (73) is formed as a hollow body, and the guide shaft (60) of the compressed air hammer (21) which projects from the piston rod (73) at the front longitudinally holding the piston rod (73) is mounted on a radial support bearing (115) situated in the front region of the piston rod (73).
14. Device according to Claim 12 or 13, characterised in that the length (L) of the piston (72) is greater than its stroke length (H), that on the circumference of the piston (72) is situated a recess (78) extending preferably over the whole circumference surface, its length (l) corresponding approximately to the stroke length (H), that the recess (78) is joined to the admission chamber of the compressed air hammer (21) by a connecting pipe (77, 46.1) and that a connection opening (85) for the pressure medium is so situated in the circumference wall (84) of the operating cylinder (75) of the cylindrical piston system that in every stroke position of the piston (72) it is in connection with the recess (78).
15. Device according to claim 14, characterised in that the buffer or buffers (58,66) is or are formed by a compression spring or a part consisting of an elastic material such as rubber or plastic.
16. Device according to at least one of Claims 10 to 15, characterised in that the rear buffer (66) is located in the piston (72) between the rear end of the compressed air hammer (21) and the interior space (46.1) which is turned towards it.
17. Device according to at least one of Claims 1 to 16, characterised in that a chamber (46.1,93) is provided in the piston (72), to the rear of the compressed air hammer (21) in which it is possible to act upon with compressed air and that this chamber (46.1, 93) is limited by an insert (92) which is inserted, preferably screwed, into a rear recess in the piston (72) and formed inwards in the shape of a cup.
18. Device according to at least one of Claims 1 to 17, characterised in that several strikers (21.1) or parts thereof of different weight are associated with the rapping hammer (21) as spare parts.

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