GB2587265A

GB2587265A - Device to measure the wear of a gun barrel

Info

Publication number: GB2587265A
Application number: GB2010327.1A
Authority: GB
Inventors: Goudet Anne; Pichot Patrice; Stephenson Colin; Arnoult Christophe
Original assignee: Cta Int; CTA International SAS
Current assignee: Cta Int; CTA International SAS
Priority date: 2019-07-04
Filing date: 2020-07-06
Publication date: 2021-03-24
Anticipated expiration: 2040-07-06
Also published as: GB202010327D0; FR3098293A1; FR3098293B1; GB2587265B

Abstract

A device for measuring wear of a gun barrel comprises a gauge 3 for inserting into a gun chamber, the gauge 3 having an end piece 4. An indicator 5 is joined to the gauge 3 by joining means 6, 7, which may be a bayonet coupling. The indicator 5 is provided with a scale 8 which provides an indication, in use, of gun barrel wear

Description

Title of the invention: Device to measure the wear of a gun barrel Technical scope The technical scope of the present invention is that of devices and processes to measure the wear of gun barrels and in particular cannon barrels.

Prior Art

it is well known for a gun barrel to become worn progressively with the firing of ammunition and the point is to determine when exactly the barrel needs to be changed. Many devices have been proposed to know the state of wear of a cannon so as to avoid firing incidents. It is known to 15 perform an examination via the muzzle of the barrel or to fully disassemble the barrel, which is a difficult operation that requires handling means.

Additionally, during a firing camnaign, for example during a field intervention, it is essential to determine the state 20 of wear of the barrel so as to decide upon the removal of the gun from its firing position.

Patent US-8091266 discloses, for example, a gun maintenance tool kit. One of the tools proposed is intended to Inspect the wear of the gun barrel. To this end, a gauge is inserted by the barrel muzzle, such gauge being precisely machined to check the barrel's diameter.

Reference may also be made to document KR20140124889 that proposes the use of a system to visualize the barrel walls, to patent EP-1291599 that proposes the use of an endoscope, to patent US-4407071 that proposes a probe with fingers that come into contact with the barrel walls, to patent US-3914996 that proposes to measure the strain in the barrel after each firing. Ail of these documents demonstrate the necessity of knowing the state of wear of a gun barrel when it is being used.

It can be seen that all these documents either require the barrel to be dismounted, or the use of visual inspection means or other devices.

Summary of the invention

The purpose of the invention is to propose a device to measure the wear of a aun barrel that enables this measurement to take place in the field without the barrel needing to be dismounted, this using technically simple means and an easily implemented process.

The invention thus relates to a device to measure the wear of a gun barrel, wherein it comprises a gauge inserted into the gun chamber, an indicator inserted into the percussion sleeve and incorporating a calibrated end piece, the gauge and inAicator being aligned along the barrel axis by rotation of the chamber, the gauge and the indicator being provided with additional joining means to ensure the translation of the gauge and its insertion at the forcing cone, the indicator being fitted with a scale to enable the barrel wear to be determined.

According to one characteristic of the invention, the gauge is mounted able to slide in a support whose external dimensions correspond to those of the chamber.

According to another characteristic of the invention, the additional joining means for the gauge and the indicator are formed of a bayonet coupling.

The invention also relates to a process to measure the wear of a barrel using the device according to any one of the previous Claims, wherein it incorporates the following steps: - the lateral insertion of the gauge equipped with its 25 support into the gun chamber, - the rotation of the gun chamber to align it with the barrel axis, - the removal of the gun's percussion line, - introduction of the indicator in place of the percussion 30 line, - coupling of the gauge and the indicator using the additional joining means, - translation of the indicator inside the chamber so as to bring the gauge up to the forcing cone, -reading of the penetration depth of the indicator by means of the scale with respect to a fixed point on the gun. Advantageously, the fixed point of the gun is constituted by the free guidance opening of the percussion line.

A first advantage of the measurement device according to the invention lies in its simple design in the form of three elements that avoid the barrel having to be dismounted, thereby gaining time.

Another advantage of the invention lies in the ease of implementation which requires little intervention on the gun, these interventions being common during the use of the gun.

Yet another advantage 'ties in the immediate evaluation of the barrel wear in the field of manoeuvres of the gun.

Brief description of drawings

Other characteristics, particulars and advantages of the invention will become apparent from the additional description given hereafter of the particular embodiments, with reference to the drawings, in which: -[FIG 1] shows a gun for which the degree of barrel wear needs to be known, - [FIG 2] shows an exploded view of the device according to the invention, - [FIG 3] is a view showing the insertion of the gauge 2C into the gun, - [FIG 4] is a view showing the insertion of the indicator and its alignment with the gauge along the barrel axis, and - [FIG 5] is a view showing the position of the device according to the invention in its measuring position.

Detailed description of the embodiments of the invention The invention will now be described in greater detail. As indicated above, the use of the device according to the invention does not require the gun to be disassembled for the barrel to be uncoupled from the chamber and examined. Since the barrel is a relatively heavy part, this would require handling wears that are impossible to provide in a field of manoeuvres. It is known empirically that gun barrel wear appears after a certain number of firings. This requires the point of wear rendering the gun unusable to be known with sufficient accuracy to avoid firing incidents, or accidents for the gun crew.

Figure 1 partially shows a gun 9 and more particularly the line of fire comprising the barrel 13 fixed in a sleeve 10, the ignition chamber 11, the guidance for the percussion system 17, and the two-part percussion system 18 and 19. The measurement device according to:he invention, composed of two main parts, will be inserted along the l=ine of fire, a first elemenh of which will be positioned in the chamber 11 and the other in the percussion system guidance 17. The Figure shows that the ignition chamber 11 is in the open position, its opening 12 being apparent. It can be seen that the percussion system 18 and 19 itself has been removed. The gun thus shown is ready to rece the measurement device according to the invention.

Figure 2 shows the wear measurement device 1 according to the invention where a tube-shaped support 2, a cylindrical-shaped gauge 3, and a rod-shaped indicator 5 can be seer. The 15 gauge 3 is fitted with a calibrated end piece 4 at one extremity and with hooking means 6 at the other extremity that cooperate with the 1-.(731cator 5. During use, the gauge is mounted, tightly fit but able to slide, in the support 2. This support 2 is shaped to engage the gun chamber as will be explained hereafter. The indicator 5 is in the form of a solid rod provided with hooking means 7 at one extremity cooperating with the gauge 3 and carrying a scale 8. The means 6 and 7 may be in the form of a bayonet coupling engaged and disengaged by simply rotating the indicator 5.

Figure 3 partially shows the rear sleeve 10 of the weapon to which the barrel 13 is attached. This gun is fitted with the chamber 11 shown here in an open position. The opening 12 of this chamber can be soon in the Figure and this opening, in normal operation, allows the introduction of the =munition.

Classically, the chamber. 11 occupies two positions, the open position shown here and a closed position after a rotation of around 90° to bring it into the firing position and thus into alignment with the barrel 13. This functionality enables the gauge 3 engaged in the support 2 to be introduced into the chamber 11. It goes without saying that the support 2 is shaped to fit the dimensions of the chamber so as to be perfectly aligned with the barrel. Then, by rotating the chamber, said alignment with the barrel is performed.

Figure 4 shows a partial section of the gun 9 in which the whole percussion line has been dismounted, but not shown, since these are known elements which do not require further description. The Figure shows the percussion sheath 14 in which the indicator 5 is engaged. It goes without saying that the external diameter of the indicator 5 is close enough to that of the internal diameter of the sheath 14 to enable this indicator 5 to be inserted.

In the position occupied by the gauge in this Figure, the 10 support 2 integrating the gauge 3 can be seen fully positioned in the gun chamber 11. The end piece 4 of the gauge 3 is seen to protrude with respect to the support 2 positioned in the alignment of the barrel 13 at the entry to the barrel's forcing cone 15 The indicator 5 can also be seen coupled with the gauge 3 using joining means not visible in this Figure.

Figure 5 shows the end piece 4 of the gauge in the measurement position further to the translation action of the indicator 5 in the chamber 11. The end piece 4 is calibrated to as to fully pass the wide part of the forcing cone 15 and come up to its narrow part. 16. The penetration depth of the device 1 according to the invention in this narrow part, and thus the more or less deep insertion of the end piece 4, enables the wear of the barrel 13 to be determined. Then value given on the indicator scale 5 is read with respect to the fixed reference point constituted by the free end of the percussion system guidance 14 to know the penetration depth of the device 1. According to the value measured, the gun crew is able to determine the state of wear of the barrel 13, the number of rounds that can still be fired or the replacement of the barrel.

Thus, using simple means, iL is possible for the barrel 13 wear to be determined.

It goes without saying that the device 1 is removed from the gun in reverse order. To this end, the support 2 is brought back into the position shown in Figure 3 by pulling on the indicator 5, then by rotating the indicator 5, which releases the support 2 now back in the chamber:J. Then the indicator 5 merely has to be removed and the chamber made to rotate so as to bring it back to the position shown in Figure 1 or 3, and lastly the support. 2 with the gauge 3 is removed. The gun 9 is once again ready to be fired.

The invention also relates to a process to measure the wear of a barrel 13 using the device 1 described above. It incorporates the following steps: lateral insertion of the gauge 3 fitted with its support 2 in the gun chamber 11 the rotation of the gun chamber 11 to align it with the barrel 13 axis, removal of the gun 9 percussion line, introduction of the indicator 5 in the gun percussion system guidance 14, coupling of the gauge 3 and indicator 5 using additional joining means 6 and 7, translation of the indicator 5 inside the chamber 11 driving the gauge 3 to bring it to the forcing cone 15 of the barrel 13, reading of the penetration depth of the indicator 5 by 20 means of the scale 8 with respect to a fixed point on the gun constituted by the free end of the percussion system guidance 14.

Claims

CLAIMS1. Device (1) to measure the wear of a gun (9) barrel (13), wherein it comprises a gauge (3) inserted into the gun chamber (11), and incorporating a calibrated end piece (4), an 5 indicator (5) inserted into the percussion sleeve (14), the gauge (3) and indicator (5) being aligned along the barrel (13) axis by rotation of the chamber (11), the gauge (3) and the indicator (5) being provided with additional joining means (6, 7) to ensure the translation of the gauge (3) and its 10 insertion at the forcing cone (15) of the barrel (13), the indicator (5) being fitted with a scale (8) to enable the barrel (.13) wear to be determined.
2. Device (1) according to Claim 1, wherein the gauge (3) is mounted able to slide in a support (2) whose external 15 dimensions correspond to those of the chamber (11).
3. Device (1) according to Claim 2, wherein the length of the gauge (3) is less than or equal to that of the support (2).
4. Device (1) according to any one of the above Claims, wherein the additional joining means (6, 7) for the aauge (3) and the indicator (5) are formed of a bayonet coupling.
5. Process to measure the wear of a barrel (13) using the device (1) according to any one of the previous Claims, wherein it incorporates the following steps: -lateral insertion of the gauge (3) equipped with Ls support (2) into the gun chamber (11), - rotation of the gun chamber (11) to align it with the barrel (13) axis, - removal of the gun's percussion line, -introduction of the indicator (5) in the gun's percussion system guidance (14), - coupling of the gauge (3) and the indicator (5) using the additional joining means, - translation of the indicator (5) inside the chamber so 35 as to bring the gauge (3) up to the forcing cone (15) of the barrel (13), - reading of the penetration depth of the indicator (3) by means of the scale (8) with respect to a fixed point on the gun (9) constituted by the free end of the percussion system guidance (14).