Device to regulate the counter-recoil rate artillery cannon according to the temperature

Information

  • Patent Grant
  • 6227097
  • Patent Number
    6,227,097
  • Date Filed
    Wednesday, November 24, 1999
    25 years ago
  • Date Issued
    Tuesday, May 8, 2001
    23 years ago
Abstract
The technical scope of the invention is that of devices to regulate the counter-recoil rate of an artillery cannon according to the temperature.The regulation device according to the invention comprises a buffer co-operating with a ring, so as to ensure the gradual braking of the cannon at the end of the counter-recoil operation by rolling the brake oil through a leakage section located between the buffer and the ring. It is characterized in that it incorporates at least one modulation device comprising a heat-sensitive element made in a shape-memory alloy, such element ensuring, by its distortion, an increase in the leakage section when the temperature drops below a given threshold.Application to recoil mechanisms of artillery cannons.
Description




BACKGROUND OF THE INVENTION




The technical scope of the present invention is that of recoil mechanisms for artillery cannons.




In a known manner, an artillery cannon comprises:




a recoil mass, essentially formed by a barrel-breech assembly,




a recoil mechanism, generally hydraulic, placed between the recoil mass and a cannon top carriage.




The recoil mechanism is formed of a recoil brake and a recuperator. The recoil brake is intended to brake and limit the recoil of the recoil mass after firing. The role of the recuperator is to stock part of the recoil energy and thereafter to return it to the recoil mass to perform the counter-recoil, in preparation for further firing.




During the counter-recoil, the recoil mass is gradually braked at the end of its course, so as to avoid jolting the top carriage. This braking is generally ensured by a buffer that penetrates inside a ring rolling the oil located between the two parts. This braking device operating at the end of the counter-recoil is generally an integral part of the recoil brake.




According to the temperature, the brake oil of the recoil brake is of variable viscosity. At low temperatures, its viscosity is increased, causing the braking to slow down at the end of the counter-recoil, and thus increasing counter-recoil time. This causes the firing rates of the artillery cannon to be reduced, which is extremely disadvantageous for the weapon system.




SUMMARY OF THE INVENTION




The aim of the invention is to propose a device to regulate the counter-recoil of an artillery cannon, according to the temperature, thus enabling the afore-mentioned disadvantages to be overcome.




Thus, the subject of the invention is a device to regulate the counter-recoil rate for an artillery cannon according to the temperature, comprising a buffer co-operating with a ring, so as to ensure the gradual braking of the cannon at the end of the counter-recoil operation by rolling the brake oil through a leakage section located between the buffer and the ring, wherein said device incorporates at least one modulation device comprising a heat-sensitive element made in a shape-memory alloy, such element ensuring, by its distortion, an increase in the leakage section when the temperature drops below a given threshold.




The heat-sensitive element can, advantageously, be constituted by the ring and/or the buffer.




According to another embodiment, the heat-sensitive element can be integral with the buffer.




According to a first variant embodiment, the buffer can incorporate an additional passage for the oil whose section is modified by the modulation device displaced by the action of the heat-sensitive device. The additional oil passage can be constituted by at least one blind axial channel opening out to the fore of the buffer and by a blind radial channel made somewhere to the rear of the buffer, the two channels being inter-connected. The modulation device can comprise a tube placed inside the axial channel of the buffer, such tube being able to block the radial channel under the action of the heat-sensitive element when the temperature has reached the given threshold, such tube being displaced axially in one direction by the action of the heat-sensitive element and in the other by the action of a spring.




According to a second embodiment, the buffer can incorporate a second axial channel opening out at the end of the radial channel so as to provide the additional oil passage and the modulation device can comprise an axial rod placed inside the first axial channel, such rod being able to block the radial channel under the action of the heat-sensitive element when the temperature exceeds the given threshold. The rod can incorporate a groove for the passage of the oil and can be displaced axially in one direction by the action of the heat-sensitive element and in the other by the action of a spring so as to bring the groove opposite the radial channel of the buffer.




According to another embodiment, the rod can incorporate a radial opening for the passage of the oil located level with the radial channel of the buffer and it can be displaced angularly by the heat-sensitive element. The modulation device can comprise a flap able to block the front end of the axial channel of the buffer, such flap being displaced angularly by the heat-sensitive element.











BRIEF DESCRIPTION OF THE DRAWINGS




The invention will be better understood after reading the following description of the different embodiments, such description being made with reference to the appended drawings, in which:





FIG. 1

is a section view of a recoil brake accommodating a braking device for the counter-recoil, in the starting position,





FIG. 2

is a section view of a device to regulate the counter-recoil rate of a cannon, according to a first embodiment,





FIG. 3

is a section view of a device to regulate the counter-recoil rate of a cannon, according to a second embodiment, shown at high temperature,





FIG. 4

shows the regulation device in

FIG. 3

, at low temperature,





FIG. 5

is a section view of a device to regulate the counter-recoil rate of a cannon, according to a third embodiment, shown at high temperature,





FIG. 6

show the regulation device in

FIG. 5

, at low temperature,





FIG. 7

is a section view of a device to regulate the counter-recoil rate of a cannon, according to a fourth embodiment,





FIG. 8

is a view along A of the front end of the buffer shown in

FIG. 7

,





FIG. 9

is a section view of a device to regulate the counter-recoil rate of a cannon, according to a fifth embodiment,





FIG. 10

is a view along B of the front end of the buffer shown in

FIG. 9

, shown at high temperature,





FIG. 11

is a view along B of the front end of the buffer shown in

FIG. 9

, shown at low temperature.











DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS




With reference to

FIG. 1

, a recoil brake


1


according to prior art, incorporates a piston


2


sliding inside a cylinder


3


. Said cylinder incorporates a cover


4


mounted integral with it, and contains a fluid, generally oil.




The piston


2


thus defines, inside the cylinder


3


, a first ring-shaped chamber


5


and a second chamber


6


. It incorporates openings


7


and


8


, a first axial cylindrical bore


9


, followed by a second axial cylindrical bore


10


, of a smaller diameter. The bore


10


receives a ring


14


integral with the piston


2


, whose purpose will be explained later.




The cylinder


3


can be integral with an immobile top carriage of the artillery materiel (not shown), and the piston


2


can be integral with the recoil mass (not shown), or vice-versa, according to the type of artillery materiel.




A conical counter-rod


11


is mounted integral with the cover


4


of the cylinder


3


. The largest diameter of the counter-rod, located towards its end


12


, is of a dimension less than that of the inner bore


9


of the piston


2


, such that the oil can freely circulate between the piston


2


and the counter-rod


11


, the smallest diameter being located level with the cover


4


.




A buffer


13


is mounted integral, for example by threading, to the end


12


of the counter-rod


11


.




The oil contained in the cylinder


3


is intended, first of all, to provide braking for the relative motion of the piston/cylinder during the recoil of the recoil mass. The braking intensity depends on the geometry of the means of communication between the two chambers


5


and


6


. In this case, the means of communication are constituted by the combination of openings


7


and


8


of constant geometry and the counter-rod


11


of variable diameter over its length. During the relative piston/cylinder motion, the counter-rod


11


reduces the section of the opening


7


of the piston


2


, thereby varying the section for the oil passage between the two chambers and thus the braking intensity.




Secondly, the oil is intended to ensure the braking of the recoil mass at the end of the counter-recoil operation. To do this, the buffer


13


penetrates inside the ring


14


of the piston


2


rolling the oil through a leakage section located between the two parts. In a known manner, so as to ensure gradual braking during the counter-recoil, the buffer can be made according to at least two concepts. The first concept consists in making the outer profile of the buffer slightly conical in shape, the base of the cone being located on the side of the counter-rod


11


. The second concept consists in making one or several longitudinal grooves on the outer diameter of the buffer. This groove, or grooves, has a depth that gradually reduces as it approaches the counter-rod


11


.





FIG. 2

shows a first embodiment of a device to regulate the counter-recoil rate of a cannon according to the invention. It is a partial view of a recoil brake level with the buffer


13


, of the type described previously in FIG.


1


.




In a known manner, a slight play or leakage section


15


remains between the outer diameter


35


of the buffer


13


and the inner diameter


16


of the ring


14


. The outer profile of the buffer being, for example, slightly conical in shape, according to a known concept in prior art and as explained earlier in the text, the leakage section


15


varies according to the relative position of the buffer


13


and the ring


14


. Thus, during the counter-recoil of the recoil mass, the oil is gradually rolled in the leakage section


15


, ensuring the gradual braking of the recoil mass.




According to the temperature, the recoil brake oil can have variable viscosity that increases when the temperature drops.




In this embodiment, the buffer is a heat-sensitive element made of a shape-memory alloy.




So-called shape-memory alloys allows the manufacture of mechanical parts that, after having been subjected to strain, can recover their starting shape as soon as the temperature has reached a certain level. This effect occurs only at a specific temperature that is selected when the mechanical element is being defined.




The heat-sensitive element, subject of the invention, is made of an alloy having two reversible shape-memory states, that is it is able to ensure two different positions. Thus, in this embodiment, the diameter of the buffer will be greater at low temperatures than at high temperatures, thereby enabling the leakage section to be increased when there is high oil viscosity.




The heat-sensitive element has firstly been subjected to a so-called forming process enabling it to occupy, according to the temperature at which it is subjected, both afore-mentioned memorized shape positions or states. The forming process relies on the passage of the alloy from its austenitic-type crystallographic phase to its martensitic-type phase.




The properties of these alloys and their forming process are well known to the expert and therefore will not be described here in any further detail.




The threshold temperature that corresponds to the phase transition temperature of the alloy will easily be defined by the expert, depending on the conditions of use of the artillery materiel, on the type of oil used and the type of alloy.




The buffer made of shape-memory ally can, for example, be constituted by an alloy of the nickel-titanium, nickel-titanium-iron, nickel-aluminum, copper-zinc-aluminum or copper-aluminum-nickel composite groups.




When the oil temperature reduces going from the so-called high temperature state to the so-called low temperature state and passing through the threshold temperature, the outer diameter


35


of the buffer reduces, thereby increasing the leakage section


15


of the buffer


13


and the ring


14


.




Thus, according to the temperature, the outer diameter of the buffer


13


varies from the high temperature state to the low temperature state (and vice-versa), causing an equivalent variation in the leakage section


15


allowing a counter-recoil rate to be obtained that is substantial constant whatever the temperature and thus whatever the oil viscosity.




The expert will easily define the necessary variation in the leakage section, thus of the outer diameter of the buffer, according to the type of materiel and the type of oil used, so as to obtain a counter-recoil rate that is substantially constant whatever the temperature.




According to a variant embodiment, the heat-sensitive element can be the ring


14


, or both the ring


14


and the buffer


13


.




The advantage of this embodiment lies in that it is not necessary to have additional parts, the use of a specific, shape-memory, alloy being all that is required.





FIGS. 3 and 4

show a device to regulate the counter-recoil rate of a cannon according to a second embodiment of the invention.




In this embodiment, the buffer


13


has an additional oil passage


30


whose section is modified by a modulation device


17


.




The modulation device


17


is composed of a tube


21


having an inner bore


22


, of a tubular heat-sensitive element


20


, of a spring


26


and a plug


23


. The tube


21


is positioned inside a blind axial channel


24


of the buffer


13


. The axial channel


24


has two supports


25


and


27


of different diameters and connected together by a should


19


. The tube


21


has a shoulder


28


pressing against the heat-sensitive element


20


.The spring


26


, pressing against the plug


23


, holds the heat-sensitive element


20


in place and holds the shoulder


28


of the tube


21


against the shoulder


19


. The plug


23


, mounted integral by threading with the front


18


of the buffer, has an axial bore


29


of a greater diameter than the inner bore


22


of the tube


21


, as well as an indentation


31


, for example of the hexagonal type, intended to ensure its assembly.




The rear part


32


of the buffer incorporates a radial channel


33


that opens into the inside of the axial channel


24


.




The additional oil passage


30


is thus provided by the radial channel


33


, the axial channel


24


, the inner bore


22


of the tube


21


, and then the inner bore


29


of the plug


23


.




The tubular heat-sensitive element


20


is made of a shape-memory material of the groups of composites such as defined in the previous embodiment. This element has been formed to lengthen or shorten when the temperature threshold is passed.




Thus,

FIG. 3

corresponds to the operating situation at high temperature, thus at a low hydraulic viscosity. The heat-sensitive element


20


is consequently in its high temperature state, that is it has a small axial dimension. In this position, the spring


26


has compensated for the axial shortening of the element


20


by pushing one end


34


of the tube


21


in front of the radial channel


33


, so as to block it. The oil passage in this case occurs, in a traditional manner, via the leakage section between the buffer


13


and the ring


14


.





FIG. 4

represents a situation at low temperature, corresponding to a high oil viscosity. The heat-sensitive element


20


has reacted to the drop in temperature, moving from its high temperature state into its low temperature state as soon as the threshold temperature has been reached, by axially elongating. This elongation has caused the displacement of the tube


21


in a direction F, opening the additional oil passage


30


at the radial channel


33


.




The rolling of an oil that has a higher viscosity being more difficult, therefore slower, the passage


30


thus enables in the quantity of oil rolled to be increased and therefore the counter-recoil rate of the recoil mass to be modified, thereby making it substantially constant whatever the temperature.




This embodiment has the advantage of being able to use the definition of buffers known to prior art.





FIGS. 5 and 6

show a third embodiment of a device to regulate the counter-recoil rate of a cannon according to the invention.




In this embodiment, the modulation system


17


is composed of a spring


40


, a rod


41


, a cylindrical heat-sensitive element


42


and a threaded plug


43


. The rod


41


has a groove


44


whose purpose will be explained later.




The additional oil passage


30


is provided by a radial channel


45


and a blind axial channel


46


. The radial channel


45


opens into the axial channel


46


and passes through a second axial channel


47


in which the modulation device


17


is positioned.




The heat-sensitive element


42


is made of a shape-memory material of the group of composites such as defined in the first embodiment. This element has been formed so as to lengthen or shorten when the temperature threshold is reached.





FIG. 5

corresponds to the operating situation at high temperature, thus to a low hydraulic viscosity. The heat-sensitive element


42


is consequently in its high temperature state, that is it has a large axial dimension. In this position, the spring


40


is compressed and the radial channel


45


is blocked by the rod


41


. The oil passage in this case occurs, in a traditional manner, via the leakage section between the buffer


13


and the ring


14


.





FIG. 6

represent a low temperature situation, corresponding to a high oil viscosity, where the heat-sensitive element


42


has reacted to the drop in temperature by shortening axially, moving from its high temperature state into its low temperature state. This compression has caused the displacement of the rod


41


in direction F, under the action of the spring


40


, until groove


44


is located at the radial channel


45


, opening additional oil passage


30


. The oil passage in this case occurs via the combination of the leakage section between the buffer


13


and the ring


14


and the additional passage


30


.




The advantage of this embodiment, which is the preferred embodiment, lies in that the heat-sensitive element is not subjected to the pressure of the oil during operation.





FIG. 7

represents a fourth embodiment of a device to regulate the counter-recoil rate of a cannon according to the invention.




This embodiment differs from the previous one only in the design of the modulation system


17


. Said system is composed of a rod


50


and a heat-sensitive element


53


. The rod


50


incorporates a radial opening


51


and a shoulder


52


.




The front end of the buffer incorporates a cap


54


that holds the rod


50


in place axially. The cap is perforated by a bore


57


intended to enable the passage of the oil.





FIG. 8

is a view along A of the front end of the buffer


13


, without the cap


54


.




The heat-sensitive element


53


is constituted by a spiral spring integral firstly with the buffer


13


by one of its ends


55


, for example by means of screws, and secondly to the rod


50


by its other end


56


, which is, for example, introduced into a slot made in the end of the rod.




The spiral spring


53


is made of a shape-memory material of the group of composites such as defined in the first embodiment. This element has been formed so as to lengthen or shorten when the threshold temperature is reached.




When the temperature drops and after the threshold temperature has been reached, the spiral spring


53


moves from its high temperature state to its low temperature state. It reacts by shortening, thereby causing an angular displacement of the rod


50


that brings the opening


51


into alignment with the radial channel


45


such as to open the additional oil passage


30


. The oil passage occurs therefore by the combination of the leakage section between the buffer


13


and the ring


14


and the additional oil passage


30


.




On the contrary, when the temperature rises, the spiral spring


53


elongates after the temperature threshold has been reached, thereby causing an angular displacement in the opposite direction of the rod


50


so as to close the radial channel


45


.




The oil passage in this case occurs, in a traditional manner, via the leakage section between the buffer


13


and the ring


14


.





FIG. 9

shows a fifth embodiment of a device to regulate the counter-recoil rate of a cannon according to the invention.




This embodiment only differs from the previous one in the design of the modulation system


17


. Said system is composed of a flap


60


integral with a heat-sensitive element


61


in the shape of a bent blade. Said blade is integral with the buffer


13


, for example by means of screws.




The front end of the buffer also incorporates a cap


54


.




The heat-sensitive blade


61


is made of a shape-memory material of the group of composites such as defined in the first embodiment. This element has been formed to open or close when the threshold temperature has been reached.





FIG. 10

represents the front end of the buffer


13


along B, without cap


54


.




It represents a high temperature situation, corresponding to a low oil viscosity, where the heat-sensitive blade


61


is in its high temperature state. The flap


60


incorporates an opening


62


that is in an offset position with respect to the passage


30


. Said passage being closed, the oil passage in this case occurs, in a traditional manner, via the leakage section between the buffer


13


and the ring


14


.





FIG. 11

represents a low temperature situation, corresponding to a high oil viscosity, where the heat-sensitive blade


61


has reacted to the drop in temperature by unfolding, moving from its high temperature state to its low temperature state, thereby causing the angular displacement of the flap


60


in a direction G such as to bring the opening


62


opposite the passage


30


. The leakage section is thus increased by the passage


30


.




Naturally, these braking devices for the recoil mass at the end of the counter-recoil operation can be integrated into another type of recoil brake. In particular, they can be mounted onto a recoil brake fitted with a sheath or jacket incorporating a profiled opening instead of a counter-rod system.



Claims
  • 1. A device to regulate the counter-recoil rate for an artillery cannon according to the temperature, comprising a buffer co-operating with a ring, so as to ensure the gradual braking of said cannon at the end of the counter-recoil operation by rolling a brake oil through a leakage section located between said buffer and said ring, said device incorporates at least one modulation device comprising a heat-sensitive element made in a shape-memory alloy, said element ensuring, by its distortion, an increase in said leakage section when the temperature drops below a given threshold.
  • 2. A device according to claim 1, wherein said heat-sensitive element is constituted by the ring.
  • 3. A device according to claim 1, wherein said heat-sensitive element is integral with said buffer.
  • 4. A device according to claim 3, wherein said heat-sensitive element is constituted by said buffer.
  • 5. A device according to claim 3, wherein said buffer incorporates an additional oil passage whose section is modified by said modulation device displaced by the action of said heat-sensitive device.
  • 6. A device according to claim 5, wherein said additional oil passage is constituted by at least one blind axial channel opening out to the fore of said buffer and by a blind radial channel made somewhere to the rear of said buffer, said two channels being inter-connected.
  • 7. A device according to claim 6, wherein said modulation device comprises a tube placed inside said axial channel of said buffer, said tube being able to block said radial channel under the action of said heat-sensitive element when the temperature has reached the given threshold, said tube being displaced axially in one direction by the action of said heat-sensitive element and in the other by the action of a first spring.
  • 8. A device according to claim 6, wherein said buffer incorporates a second blind axial channel opening out at the end of said radial channel so as to provide said additional oil passage and wherein said modulation device comprises an axial rod placed inside said first axial channel, said rod being able to block said radial channel under the action of said heat-sensitive element when the temperature exceeds said given threshold.
  • 9. A device according to claim 8, wherein said rod incorporates a groove for the passage of the oil and is displaced axially in one direction by the action of said heat-sensitive element and in the other by the action of a second spring so as to bring said groove opposite said radial channel of said buffer.
  • 10. A device according to claim 8, wherein said rod incorporates a radial opening for the passage of the oil located at said radial channel of said buffer and it can be displaced angularly by said heat-sensitive element.
  • 11. A device according to claim 6, wherein said modulation device comprises a flap able to block the front end of said axial channel of said buffer, such flap being displaced angularly by said heat-sensitive element.
Priority Claims (1)
Number Date Country Kind
98 14929 Nov 1998 FR
US Referenced Citations (3)
Number Name Date Kind
H217 Jorczak Feb 1987
5168120 Rossel Dec 1992
5663521 Mandereau et al. Sep 1997
Foreign Referenced Citations (1)
Number Date Country
1505915 Dec 1967 FR