Elongated-member-driving apparatus – Explosive-type driving means
Reexamination Certificate
2000-02-08
2001-09-11
Smith, Scott A. (Department: 3721)
Elongated-member-driving apparatus
Explosive-type driving means
C227S010000, C089S026000
Reexamination Certificate
active
06286743
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to an explosive powder-charge operated setting tool including a first part provided with a cartridge socket, an opposite second part having a mating surface which partially covers an axial projection surface of the cartridge socket, a circular cut-out provided adjacent to the first part, and at least one connection channel, and an annular sealing member located in the circular cut-out of the second part, with the sealing member being supported on the first part outside of the cartridge socket, and with the at least one connection channel extending from the cartridge socket up to a working surface of the sealing member facing in a direction opposite to the setting direction.
2. Description of the Prior Art
International application WO96/39281 discloses an explosive powder charge-operated setting tool having a guide cylinder with an inner bore in which a drive piston is displaceably arranged. A breech block, which is arranged coaxially with the guide cylinder, adjoins the guide cylinder at its side facing in a direction opposite to the setting direction. The breech block is provided with a cartridge socket in its region facing in the setting direction. The inner width of the cartridge socket increases toward the free end of the breech block.
The guide cylinder has, in its end region facing in a direction opposite to the setting direction, a circular cut-out in which a sealing member is fixedly arranged. The circular cut-out divides the end region of the guide cylinder, that faces in the direction opposite to the setting direction, in a central cylindrical section and a circular outer section which surrounds the central cylindrical section. The free end of the central cylindrical section forms a mating surface which secures a cartridge in the cartridge socket. The mating surface projects beyond the remaining portion of the end surface in the direction opposite to the setting direction.
Upon ignition or firing of the cartridge, the propellant gas pressure reaches, through the connection channel which connects the cartridge socket with the cut-out, the inner wall of the circular sealing member which has a U-shaped cross-section the opening of which is opened toward the central longitudinal axis of the sealing member. The propellant gas pressure, which is generated upon firing of the cartridge, does not act only in the setting direction in the setting tool disclosed in the above-mentioned International application. Rather, it also acts in two parallel directions opposite to the setting direction, so that the sealing member expands in two opposite directions.
Accordingly, an object of the present invention is to provide an explosive powder charge-operated setting tool in which the sealing element reliably seals the cartridge-receiving chamber and is pressed toward the first part with a bearing pressure corresponding to the propellant gas pressure.
SUMMARY OF THE INVENTION
This and other objects of the present invention, which will become apparent hereinafter, are achieved by providing an explosive powder charge-operated setting tool including a first part provided with a cartridge socket, an opposite second part having a mating surface which partially covers an axial projection surface of the cartridge socket, a circular cut-out provided adjacent to the first part, and at least one connection channel, and an annular sealing member located in the circular cut-out of the second part and displaceable parallel to a setting direction relative to the second part, with the sealing member being supported on the first part outside of the cartridge socket, and with the at least one connection channel extending from the cartridge socket up to a working surface of the sealing member facing in a direction opposite to the setting direction.
The arrangement of the circular sealing member according to the present invention provides for pressing of the sealing member against the first part dependent on the propellant gas pressure. Upon firing of the cartridge, the generated propellant gas pressure is conducted through the connection channels, which are formed in the second part, to the bottom of the circular cut-out and there propagates along a working surface of the sealing member which faces in the direction opposite to the setting direction. The sealing member, which is displaceable in the cut-out parallel to the setting direction, will be pressed against the first part, via an intermediate member and the cartridge cover, to a greater or smaller degree, dependent on the magnitude of the propellant gas pressure.
In order to insure that the propellant gas, which is generated upon firing of the cartridge, reaches the working surface of the sealing member, the sealing member should be spaced from the cut-out bottom. To this end, the distance between the flanged section of the sealing member and the working surface of the sealing member is smaller than the depth of the cut-out measured parallel to the setting direction. With the flanged section, the sealing member is supported, in the direction opposite to the setting direction, against an end surface of the second part facing in the setting direction.
A small amount of the propellant gas, which acts on the working surface of the sealing member, can escape between the outer surface or wall of the sealing member and the outer wall of the circular cut-out.
In order to carry away this small amount of the escaped propellant gas from the setting tool interior, advantageously, a ventilation channel is provided, which extends between the flanged section of the sealing member and the stop surface offset with respect to the mating surface in a direction opposite to the setting direction.
In order to prevent leakage of the propellant gas between the outer wall of the sealing member and the outer wall of the circular cut-out, the sealing section of the sealing member, advantageously, cooperates with a sealing region of the circular cut-out.
For economical and manufacturing reasons, advantageously, the sealing region is formed by at least one plate seal arranged in a side groove formed in the circular cut-out.
In order to provide for a large-surface support of the cartridge in the cartridge socket, advantageously the largest inner width of the cartridge socket projects, in the radial direction, beyond a mating surface of the second part.
In order to arrange the cartridge socket as close as possible to the inner bore of the guide cylinder, preferably, the first part is formed as a guide cylinder, and the second part is formed as a breech block.
The novel features of the present invention, which are considered as characteristic for the invention, are set forth in particular in the appended claims. The invention itself, however, both as to its construction and its mode of operation, together with additional advantages and objects thereof, will be best understood from the following detailed description of preferred embodiment, when read with reference to the accompanying drawings.
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patent: 5777256 (1998-07-01), Simon et al.
Hilti Aktiengesellschaft
Sidley Austin Brown & Wood LLP
Smith Scott A.
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