DE1239256B - Impact device for compressed air operated countersink hammers - Google Patents

Description

FEDERAL REPUBLIC OF GERMANY

GERMAN

PATENT OFFICE

EDITORIAL

Int. CL:

E 21 c

German class: 5b -7/04

Number: 1 239 256

File number: B 87002 VI a / 5 b

Filing date: May 6, 1966

Open date: April 27, 1967

The invention relates to an impact device for compressed air-operated countersinking hammers, the cylinder spaces of which have exhaust holes that can be covered by free-flying pistons.

There are known countersinking hammers in which the exhaust ducts for all the compressed air to the the lower end of the cylinder open into the open and the pistons on the lower half of the Cylinder inner jacket stepping bores controls. With this training, the exhaust ducts in the Cylinder jacket out and to prevent a pressure loss of the already released compressed air accordingly have large cross-sections, thereby reducing the diameter of the device entering the borehole must be big. Another disadvantage of this hammer is that the borehole does not close can also be flushed with fresh air at any time during the piston stroke.

In order to avoid these disadvantages, it is proposed according to the invention, the exhaust holes the working spaces of the cylinder in an axial, known per se, penetrating the cylinder To arrange pipe. Appropriately, to increase the flushing effect of the drilling base, the axial Fresh air is constantly supplied to the pipe.

The object of the invention is explained using an exemplary embodiment shown in the drawing, which represents a hammer drill with the drill bit in longitudinal section.

In the hammer cylinder 1, to which on the one hand the hammer rod 2 and on the other hand the front housing 3 adjoins, a cylinder liner 4 is drawn, which has bores 5 to control channels 6, which are expediently guided between the cylinder and the bushing for piston control. In the cylinder liner 4, an annular piston 7 is arranged, which slides along an axial tube 8 which carries bores 9 for discharging the used working air. This axial tube 8 extends, on the one hand, to the end face of the cylinder cover 10, which closes the cylinder space against the control housing 12, and, on the other hand, deep into the axial bore 11 of the intermediate piece 13, on the end face of which the percussion piston 7 strikes during the working stroke. The intermediate piece is partly guided on the inner wall of the cylinder liner 4 and partly through ribs 14 in the front housing 3, which are provided in grooves on the neck 15 of the intermediate piece 13. A thread for fastening the drill bit 16 is provided at the end of the intermediate piece on the drill side. The drill bit is equipped with hard metal cutting bodies 17 and has a central channel 18 as well as additional ones for the drill-impact device for compressed air-operated
Countersink hammers

Applicant:

Gebr. Böhler & Co. Aktiengesellschaft, Vienna;

Branch office:

Gebr. Böhler & Co. Aktiengesellschaft, Vienna,

Büderich sales office

Named as inventor:

Ing.Josef Huszar, Kapfenberg, Styria

(Austria)

Claimed priority:

Austria from May 10, 1965 (A 4200/65)

axis inclined flushing channels. An axial bore 19 is provided in the cylinder cover which connects to the fresh air duct is in constant contact with the hammer drill, so that even during the air supply to the Hammer drill fresh air is supplied to the drill bed. This additional fresh air not only improves the cleaning of the drill bed by the exhaust air from the cylinder chambers, but also improves the How the impact device works, as the one that sweeps past perpendicular to the axis of the exhaust air bores Fresh air achieves an injector effect and thereby creates a negative pressure through which the exhaust air comes out the cylinder chambers is sucked.

A particular advantage of the axial exhaust air duct in the hammer is that due to the location of the exhaust air duct, the risk of freezing caused by the sudden escape of the relaxed exhaust air into the Free entry, completely banned. This risk of freezing is also caused by the admixture of fresh air reduced even further.

Due to the inventive guidance of the exhaust air in an axial tube and the arrangement of the Compressed air channels in channels between the hammer cylinder and the cylinder liner can be the cross-section of the impact device can be reduced very significantly with the same performance, since the cross-section for the relaxed exhaust air must be chosen larger than for the compressed air to return the hammer piston in his upper dead position.

709 577/12

The hammer drill of the embodiment shown in the drawing has one of the known ones Slide controls, the functionality of which is completely the same as the functionality of the controller in previously known Devices is.

To replace the drill bit, recesses are useful on the front housing for attack a key provided, whereby the drill bit can be unscrewed more easily from the intermediate piece can. '""'

Claims (3)

Patent claims: 1. Impact device for pneumatic countersinking hammers, the cylinder chambers of which are free flying pistons have coverable exhaust bores, characterized in that the exhaust holes (9) from the working spaces of the cylinder (4) in a known per se, the Cylinder penetrating axial tube (8) are arranged, which directly or indirectly into a axial bore (11,18) of the drill bit (17) is inserted. 2. Impact device according to claim 1, characterized in that the tube (8) at its upper Front side is connected to the compressed air supply channel by a channel (19). 3. Impact device according to claim 1 or 2, characterized in that the compressed air channels for the control and the piston return - as known per se - are arranged between the hammer cylinder and the cylinder liner. 1 sheet of drawings 709 577/12 4.67 © Bundesdruckerei Berlin