SUPPORT OF FLUSHING TUBE

SUPPORT DE TUBE DE BALAYAGE

English Abstract

ABSTRACT
The present invention relates to a device in a
hydraulic striking apparatus comprising a body, a
cylinder space, a flushing tube, a striking piston
attached to the body with bearings on both sides of the
cylinder space and comprising an axial bore for the
flushing tube, and a canal between the bore of the
piston and the flushing tube, the improvement being,
that the flushing tube rests against the piston by
means of supporting members which are parts of the
flushing tube and so designed that there remain canals
between them for conveying air and lubricant along the
canal between the bore of the piston and the flushing
tube.

Claims

THE EMBODIMENTS OF THE INVENTION IN WHICH AN EXCLUSIVE
PROPERTY OR PRIVILEGE IS CLAIMED ARE DEFINED AS FOLLOWS:
1. A device in an hydraulic striking apparatus
comprising a body having an axial generally cylindrical interior
space, a flushing tube, a striking piston axially slidable within
the cylindrical space and comprising an axial bore for the
flushing tube, and a canal between the bore of the piston and
the flushing tube, the flushing tube resting against the piston
by means of supporting members which are parts of the flushing
tube and so designed that there remain canals between them for
conveying air and lubricant along the canal between the bore of
the piston and the flushing tube.
2. A device according to claim 1, in which the supporting
members are elongated, radially protruding members which are
fastened to the surface of the flushing tube.
3. A device according to claim 1, in which the supporting
members consist of projections of the flushing tube, the transverse
section of the flushing tube being polygonal.
4. A device according to claim 1, 2, or 3 in which the
number of the supporting members is three.
5. A device according to claim 1, 2, or 3 in which a small
portion of the bore in the piston is of reduced width and this
portion is in contact with the supporting members.

Description

7i05
Finnish patent 50940 and Canadian patent 1,027,010
disclose hydraulic striking apparatus comprising a body having an
axial generally cylindrical space, a flushing tube, a striking piston
axially slidable within the cylindrical space and comprising an
axial bore for the flushing tube. The diameter of this bore is a
little larger than the outer diameter of the flushing tube,
whereby an annular canal remains between the piston and the
flushing tube. The object of this canal is to convey lubricant
from the space behind the piston to the space in front of the
piston and to serve as a pressure balancing canal for the spaces
at the ends of the piston.
The flushing tube rests on the rear cover of the
striking apparatus and its front part is supported by the packing
of the drill shank. In the known apparatus the flushing tube is
without support between the said points. This causes at least
the following disadvantages. During the drilling the flushing
tube easily starts to vibrate, whereupon it can easily break. The
flushing water can also seep through the packing of the drill
shank into the space in front of the piston which causes cavitation
in this space. For the same reason the lubrication of the front
end of the striking apparatus becomes less good. While the
; striking apparatus is pushed into the drill shank the flushing
tube easily hits the flat end surface of the shank without meeting
the bore. Thereby the end of the flushing tube is damaged. For
the same reason also the packing of the drill shank can be
damaged.
The present invention reduces or eliminates the
disadvantages and provides a device in an hydraulic striking
apparatus comprising a body having an axial generally cylindrical -
interior space, a flushing tube, a striking piston axially
slidable within the cylindrical space and comprising an axial bore
for the flushing tube, and a canal between the bore of the piston
and the flushing tube, the flushing tube resting against the
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piston by means of supporting members which are parts of the
flushing tube and so designed that there remain canals between
them for conveying air and lubricant along the canal between the
bore of the piston and the flushing tube.
In the following the invention will be described in
greater detail with reference to the accompanying drawings in which
Fig. 1 is an elevational view of the striking apparatus.
Fig. 2 is a sectional view taken along line A-A in Fig.
1 and shows one way of arranging the supporting.
Fig. 3 is a sectional view taken along line A-A in Fig.
1 and shows another way of arranging the supporting.
In the cylinder space 12 of the body 1 there is a
reciprocating striking piston 2. In the body 1 there is a tool 4.
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While reciprocating, the striking piston 2 strikes the end of the
tool 4. Inside the striking apparatus, in a bore 15 in the piston
2 there is a flushing tube 3, one end of which is supported by the
body 1 and the other end of which is pushed into the tool 4. The
shank packing 5 is in the tool 4. It prevents the entry of flushing
water into the striking mechanism. The flushing tube 3 is provided
with supporting members 11 or 14 which lean against the inner
surface of the bore 15 in the piston. Between the supporting
members 11, 14 there remain canals 16 or 17 for the flow of air and
lubricant conveyed by the air from space 7 to space 8 or in the
opposite direction. The spaces 7 and 8 at the ends of the striking
piston 2 are in connection with each other through the annular
space 6 and the canals 16, 17 of the supporting part 11, 14. The
lubricating air is conveyed through the stud 13 and the canal 9
into the space 7 and from there through the striking piston 2 into
the space 8 from which it is conveyed to the tool 4 to lubricate
this. The flushing water is conveyed through the stud 10 into the
flushing tube 3 and further into the tool 4.
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