Memory alloy pin puller

Abstract

The application discloses a memory alloy pin puller and belongs to the technical field of fuze safety mechanisms. The memory alloy pin puller comprises a first shell, a second shell, a first elastic member, a second elastic member, a third elastic member, a pin shaft and a heating sheet. The first elastic member is made of a shape memory alloy material. The second shell is arranged in the first shell, the second elastic member is sleeved on the periphery of the second shell, one end of the second elastic member abuts against the second shell, and the other end of the second elastic member abuts against the first shell. The heating sheet is connected to the bottom of the first shell, one end of the first elastic member abuts against the heating sheet, and the other end of the first elastic member abuts against the second shell. One end of the pin shaft is arranged in the second shell, the other end of the pin shaft can extend out of the second shell, and the third elastic member is sleeved on the periphery of the pin shaft. The memory alloy pin puller further comprises a limiting ball, a through hole is formed in the second shell and corresponds to the limiting ball, and the limiting ball is arranged in the through hole and can abut against the pin shaft. In the memory alloy pin puller, the stroke of the pin shaft moving downward is improved, the limiting ball is arranged to realize self-locking, and the pin pulling process is reliable.

Description

TECHNICAL FIELD

[0001] The present application belongs to the technical field of fuze safety mechanism, and particularly relates to a memory alloy pin puller. BACKGROUND

[0002] The shape memory alloy has shape memory effect. When the heating temperature exceeds the phase transition temperature of the material, the transformation from martensite to austenite occurs. At this time, the material will try to restore to the shape before deformation. If the material is constrained at both ends, a large restoring force is generated in the material. The shape memory alloy with double shape memory effect can realize repeated contraction by heating or cooling. The shape memory alloy pin puller can be made by using this feature.

[0003] At present, the shape memory alloy pin puller designed with the shape memory alloy spring as a driving part based on the above technical characteristics has been widely used. In some schemes of the memory alloy pin puller, the heating sheet is powered through the mechanism, the heating sheet heats the shape memory alloy spring, the shape memory alloy spring reaches the reverse phase change temperature, the shape memory alloy spring restores the deformation, the spring elongates, the safety lever moves, and when the power supply is stopped, the temperature of the shape memory alloy spring decreases, and the spring retracts to the original non-powered state. This scheme has the problems of small driving displacement and the safety lever retracts after power off.

[0004] In some other schemes of the shape memory alloy pin puller, the shape memory alloy wire is used in a reciprocating reversing series connection mode at the two ends of the square inner cylinder, so that the pin puller realizes the maximum displacement increment. However, it still has the problems of small displacement and the pin puller cannot realize the power-off self-locking function. SUMMARY

[0005] In view of one or more of the above defects or improvement needs of the prior art, the present application provides a memory alloy pin puller which has large displacement and can realize self-locking.

[0006] To achieve the above purpose, the present application provides a memory alloy pin puller, which comprises a first shell, a second shell, a first elastic member, a second elastic member, a third elastic member, a pin shaft and a heating sheet; the first elastic member is made of shape memory alloy material;

[0007] The second shell is arranged in the first shell, the second elastic member is sleeved on the outer periphery of the second shell, one end of the second elastic member abuts against the second shell, and the other end of the second elastic member abuts against the first shell; the first shell is connected with the heating sheet at the bottom, one end of the first elastic member abuts against the heating sheet, and the other end of the first elastic member abuts against the second shell;

[0008] One end of the pin shaft is arranged in the second shell, and the other end of the pin shaft can extend out of the second shell; the third elastic member is sleeved on the outer periphery of the pin shaft, and one end of the third elastic member abuts against the pin shaft, and the other end of the third elastic member abuts against the second shell.

[0009] Further comprising a limiting ball, the second shell is provided with a through hole corresponding to the limiting ball, the limiting ball is arranged in the through hole and can abut against the pin shaft.

[0010] As a further improvement of the application, the plane of the pin shaft abutting against the limiting ball is neither parallel to the vertical direction nor parallel to the horizontal direction.

[0011] As a further improvement of the application, the pin shaft comprises a first limiting part, capable of limiting the third elastic member and the limiting ball.

[0012] As a further improvement of the application, the second shell comprises a second limiting part, capable of limiting the second elastic member.

[0013] As a further improvement of the application, further comprising a pressing screw; the second shell is provided with a thread outside corresponding to the pressing screw, so that the pressing screw is connected with the second shell in cooperation.

[0014] The pressing screw is connected to one end of the pin shaft in the second shell, which can extend out of the second shell.

[0015] As a further improvement of the application, the first shell comprises an upper shell, a lower shell and a connecting piece, and the upper shell and the lower shell are connected through the connecting piece.

[0016] As a further improvement of the application, the plane of the pin shaft abutting against the limiting ball is a circular arc surface.

[0017] As a further improvement of the application, the first shell is provided with a first accommodating groove corresponding to the heating sheet, so that the heating sheet can be accommodated therein.

[0018] As a further improvement of the application, the second shell comprises a third limiting part, which is located at the bottom of the second shell and has a volume matched with the first accommodating groove, so that the third limiting part can be partially accommodated in the first accommodating groove.

[0019] As a further improvement of the application, the second shell is provided with a second accommodating groove corresponding to the first elastic member, and the first elastic member is partially accommodated in the second accommodating groove.

[0020] The above improved technical features can be combined with each other as long as they do not conflict with each other.

[0021] Overall, the above technical solutions conceived by the present application have the following beneficial effects compared with the prior art:

[0022] (1) The memory alloy pin extractor of the present application, by placing two elastic members, makes the overall movement stroke of the pin shaft the movement stroke of the second elastic member pushing the second shell to move downward plus the stroke of the third elastic member pushing the pin shaft to move downward, which is greatly improved compared with the stroke of the pin shaft moving downward alone. Moreover, the two elastic members provide driving force, and the driving force is also greatly improved.

[0023] (2) The memory alloy pin extractor of the present application, by the setting of the limiting ball, makes each spring be able to keep a compressed state and not move unexpectedly in the initial state, and after being in place, the limiting ball can also limit the second shell to avoid the first elastic member from affecting the pin extraction process after the heating sheet is not heated.

[0024] (3) The memory alloy pin extractor in the present application, by the setting of the second elastic member and the third elastic member, makes the stroke of the pin shaft moving downward be improved, and the two elastic members make the driving force also be greatly improved. Moreover, the setting of the limiting ball makes the first elastic member be limited and fixed when it wants to restore to the original state, realizes self-locking, ensures the reliability of the pin extraction process, and has good application prospect and use value as a whole. BRIEF DESCRIPTION OF DRAWINGS

[0025] In order to more clearly illustrate the technical solutions in the embodiments of the present application, the drawings needed to be used in the embodiments will be briefly introduced as follows. Obviously, the drawings in the following description are only some embodiments of the present application, and other drawings can also be obtained by those skilled in the art without creative labor on the basis of these drawings.

[0026] Figure 1 is the initial state schematic diagram of the overall structure of the memory alloy pin extractor in the embodiment of the present application;

[0027] Figure 2 is the in-place state schematic diagram of the overall structure of the memory alloy pin extractor in the embodiment of the present application;

[0028] Figure 3 is the exploded view of the overall structure of the memory alloy pin extractor in the embodiment of the present application;

[0029] In all the drawings, the same reference signs represent the same technical features, specifically:

[0030] 1, first shell; 2, second shell; 3, first elastic member; 4, second elastic member; 5, third elastic member; 6, pin shaft; 7, heating sheet; 8, limiting ball; 9, compression screw;

[0031] 101, upper shell; 102, lower shell; 103, connecting piece; 1021, first accommodating groove;

[0032] 201, second limiting portion; 202, third limiting portion; 203, second accommodating groove;

[0033] 601, first limiting portion. DETAILED DESCRIPTION

[0034] In order to make the objects, technical solutions and advantages of the present application clearer, the present application will be further described in detail below with reference to the drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present application and should not be used to limit the present application. In addition, the technical features involved in the various embodiments of the present application described below can be combined with each other as long as they do not conflict with each other.

[0035] In the description of the present application, it should be understood that the terms "center", "longitudinal", "transverse", "length", "width", "thickness", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", "clockwise", "counterclockwise", "axial", "radial", "circumferential" and the like indicate the orientation or positional relationship based on the orientation or positional relationship shown in the drawings, and are only used to facilitate the description of the present application and simplify the description, and therefore cannot be understood as indicating or implying that the devices or elements referred to must have a particular orientation, be constructed and operated in a particular orientation, and therefore cannot be understood as limiting the present application.

[0036] In addition, the terms "first" and "second" are only for descriptive purposes and cannot be understood as indicating or implying relative importance or implicitly indicating the number of the technical features indicated. Therefore, the features defined with "first" and "second" can explicitly or implicitly include at least one of the features. In the description of the present application, the meaning of "a plurality of" is at least two, such as two, three, etc., unless otherwise explicitly specified and limited.

[0037] In the present application, unless otherwise explicitly specified and limited, the terms "mounting", "connection", "connection", "fixing" and the like should be understood broadly, for example, it can be fixedly connected, or it can be detachably connected, or it can be integrated; it can be mechanically connected, or it can be electrically connected; it can be directly connected, or it can be indirectly connected through an intermediate medium; it can be the internal communication of two elements or the interaction relationship between two elements, unless otherwise explicitly limited. For those skilled in the art, the specific meaning of the above terms in the present application can be understood according to the specific circumstances.

[0038] In the present application, unless otherwise explicitly specified and limited, the first feature is "on" or "under" the second feature can be that the first and second features are in direct contact, or the first and second features are in indirect contact through an intermediate medium. Moreover, the first feature is "on", "above" and "over" the second feature can be that the first feature is directly above or obliquely above the second feature, or simply means that the first feature is horizontally higher than the second feature. The first feature is "under", "below" and "under" the second feature can be that the first feature is directly below or obliquely below the second feature, or simply means that the first feature is horizontally lower than the second feature.

[0039] Embodiment:

[0040] Please refer to Figures 1-3 The memory alloy pin extractor in the preferred embodiment of the present application comprises a first shell 1, a second shell 2, a first elastic member 3, a second elastic member 4, a third elastic member 5, a pin shaft 6 and a heating sheet 7. The first elastic member 3 is a spring made of Ni-Ti shape memory alloy material, has compression characteristics after being heated to the phase transition temperature, and the compression amount is 10% to 15% of the length of the first elastic member 3. In the initial installation state, as shown in FIG. 1, the first elastic member 3 is in a compressed state, and the compression amount is 5% to 8%, which can provide driving force for the initial movement of the pin extractor. Figure 1 In the preferred embodiment, one end of the first elastic member 3 abuts against the heating sheet 7, and the other end abuts against the second shell 2. The compression amount of the first elastic member 3 can be changed after the heating sheet 7 heats it, so that the second shell 2 can move vertically to achieve pin extraction.

[0041] Further, in the preferred embodiment, the first shell 1 is preferably a cylinder with a slot in the middle, and a stepped slot corresponding to the shape of the second shell 2 is formed, which is narrow at the top and wide at the bottom, so that the second shell 2 can be placed in the first shell 1, and the second elastic member 4 can be arranged between the second shell 2 and the first shell 1. Since the pin shaft 6 is usually a cylinder, the second shell 2 is also preferably a cylinder. In this way, the second elastic member 4 is preferably a spring which is sleeved on the outer periphery of the second shell 2, and one end of the second elastic member 4 abuts against the second shell 2, and the other end abuts against the first shell 1. The second elastic member 4 is in a compressed state in the initial installation state, and the compression amount is 5% to 8%. The arrangement of the second elastic member 4 ensures the force balance between the first elastic member 3, the second elastic member 4 and the third elastic member 5 in the initial installation state, so that the limiting ball 8 is in a state of limiting the movement of the pin shaft 6. When the first elastic member 3 is retracted after being energized, the force balance between the first elastic member 3, the second elastic member 4 and the third elastic member 5 is broken, and the second elastic member 4 pushes the second shell 2 to move downward.

[0042] In detail, the first shell 1 in the preferred embodiment can be integrally formed or separately formed, and when separately formed, comprises an upper shell 101, a lower shell 102 and a connecting piece 103. The upper shell 101 and the lower shell 102 are connected through the connecting piece 103, and the bottom of the upper shell 101 is connected to the top of the upper shell 101. As shown in Figure 3 The upper shell 101 and the lower shell 102 are both composed of a cylinder and a flange, and the connecting piece 103 is selected to be a bolt. Threaded holes are correspondingly arranged on the flanges of the upper shell 101 and the lower shell 102, so that the upper shell 101 and the lower shell 102 can be connected through the bolt.

[0043] Specifically, the first shell 1 in the preferred embodiment is provided with a first accommodating groove 1021 corresponding to the heating sheet 7, so that the heating sheet 7 can be accommodated therein. Since the pin pulling process is along the vertical direction, the heating sheet 7 is preferably connected to the bottom of the first shell 1, and therefore the first accommodating groove 1021 is preferably arranged on the lower shell 102. In specific implementation, the heating sheet 7 is selected to be an electric heating sheet, and the bottom end is connected to two wires. After being electrified, the heating sheet 7 emits heat, which provides heat for the deformation of the first elastic member 3.

[0044] Preferably, the second shell 2 in the preferred embodiment comprises a third limiting part 202, which is located at the bottom of the second shell 2 and has a volume matching that of the first accommodating groove 1021, so that the third limiting part 202 can be partially accommodated in the first accommodating groove 1021. Since the first elastic member 3 can be compressed after being heated, the second shell 2 arranged above the first elastic member 3 moves downward under the action of gravity, the third limiting part 202 enters the first accommodating groove 1021 and is accommodated therein. At this time, the third limiting part 202 cannot be moved at will in the first accommodating groove 1021, so that the second shell 2 cannot be moved at will, thereby ensuring that the pin pulling process is stable and reliable.

[0045] In the preferred embodiment, the second shell 2 further comprises a second limiting part 201, which is also a cylinder, but has a larger diameter than other parts of the second shell 2. The second elastic member 4 is sleeved on the smaller diameter part of the second shell 2, so that the larger diameter second limiting part 201 can limit the second elastic member 4. In the preferred embodiment, the second shell 2 is a stepped cylindrical structure, the larger cylinder is used to limit the second elastic member 4, the upper end of the larger cylinder is a smaller cylinder, and a blind hole can be arranged in the smaller cylinder to accommodate the third elastic member 5 and the pin shaft 6. Further, the second shell 2 is provided with a second accommodating groove 203 corresponding to the first elastic member 3, and the first elastic member 3 can be partially accommodated in the second accommodating groove 203.

[0046] Further, the second shell 2 in the preferred embodiment has a cavity inside, so that the pin shaft 6 and the third elastic member 5 can be accommodated in the cavity. One end of the pin shaft 6 is arranged in the second shell 2, and the other end can extend out of the second shell 2. The memory alloy pin extractor in the preferred embodiment further comprises a pressing screw 9. The second shell 2 has a thread outside corresponding to the pressing screw 9, so that the pressing screw 9 is connected to the second shell 2. The pressing screw 9 is connected to the end of the pin shaft 6 extending out of the second shell 2, and can seal the third elastic member 5 and the pin shaft 6 in the second shell 2.

[0047] More specifically, in the preferred embodiment, the pin shaft 6 is cylindrical, and the third elastic member 5 is sleeved on the outer periphery of the pin shaft 6, with one end abutting against the pin shaft 6 and the other end abutting against the second shell 2. Similarly, the third elastic member 5 is in a compressed state in the initial installation state, and the compression amount is 10% to 15%, which serves as the driving force for the downward movement of the pin shaft 6.

[0048] In the preferred embodiment, the pin shaft 6 comprises a first limiting portion 601, which can limit the third elastic member 5 and the limiting ball 8. Similarly, the first limiting portion 601 is also cylindrical, but has a larger diameter than the other portions of the pin shaft 6. The third elastic member 5 is sleeved on the smaller diameter portion of the pin shaft 6, so that the first limiting portion 601 with the larger diameter can limit the third elastic member 5. The pin shaft 6 is preferably made of steel.

[0049] In addition, the memory alloy pin extractor in the preferred embodiment further comprises a limiting ball 8. The second shell 2 has a through hole corresponding to the limiting ball 8, and the limiting ball 8 is arranged in the through hole and can abut against the pin shaft 6. In specific implementation, the limiting ball 8 is a steel ball, and the second shell 2 has two symmetrical through holes that are in communication with the cavity inside the second shell 2, so that the limiting ball 8 can contact the pin shaft 6. In the initial state, the limiting ball 8 is arranged in the through hole and the side surface is limited in the narrower groove in the upper half of the first shell 1, which also limits the pin shaft 6.

[0050] More preferably, in the preferred embodiment, the plane of the pin shaft 6 abutting against the limiting ball 8 is neither parallel to the vertical direction nor parallel to the horizontal direction, which can convert the vertical driving force into horizontal thrust force to push the limiting ball 8 to both sides. In the preferred embodiment, the plane of the pin shaft 6 abutting against the limiting ball 8 is below a small cylinder, which can limit the limiting ball 8 and prevent the limiting ball 8 from being squeezed into the cavity inside the second shell 2 for accommodating the pin shaft 6 when the limiting ball 8 is squeezed inward. In the initial state, the amount of the limiting ball 8 extending into the lower end of the pin shaft 6 is half of the diameter of the limiting ball 8. In the preferred embodiment, the plane of the pin shaft 6 abutting against the limiting ball 8 is a circular arc surface. Since the limiting ball 8 is a spherical body, the abutting surface of the pin shaft 6 is correspondingly arranged as a circular arc surface, so that the limiting ball 8 and the pin shaft 6 fit better, and the limiting ball 8 is more susceptible to force.

[0051] In addition, in the preferred embodiment, the distance between the bottom end of the pin shaft 6 and the bottom end of the corresponding first accommodating groove 1021 in the initial state is 5-6 mm. The distance between the lower end surface of the second limiting part 201 and the upper end surface of the lower shell 102 is 3 mm, and the locking amount of the vertical direction of the locking ball 8 locked by the upper shell 101 is 1.5-2 mm.

[0052] The operation process of the memory alloy pin extractor in the application is as follows: in the initial state, the first elastic part 3, the second elastic part 4 and the third elastic part 5 are all in the compressed state, the second shell 2 is in the state shown in the figure through the force balance of the three parts, at this time, the locking ball 8 is limited by the upper shell 101, and the third elastic part 5 in the compressed state cannot push the pin shaft 6 to move downward. Figure 1

[0053] When the heating sheet 7 is powered, the heat is emitted to the first elastic part 3, when the heat reaches the phase change temperature of the first elastic part 3, the first elastic part 3 is further compressed, then the second elastic part 4 above the first elastic part 3 in the compressed state further pushes the second shell 2 to move downward, when the second shell 2 drives the locking ball 8 to move downward to the unbound state, the locking ball 8 pushes the pin shaft 6 to move downward under the action of the third elastic part 5, the two locking balls 8 are squeezed to the two sides through the conical surface below the pin shaft 6, the constraint on the pin shaft 6 is released, and the pin shaft 6 is pushed to the position under the compression resistance of the third elastic part 5, so as to realize the pin extraction function.

[0054] For the pin shaft 6, the movement stroke is the sum of the downward movement distance of the adapter cylinder and the downward movement distance of the pin shaft 6, so the movement stroke of the pin extractor is greatly improved.

[0055] When the power supply to the heating sheet 7 is stopped, the heat felt by the first elastic part 3 is weakened below the phase change temperature, and the first elastic part 3 returns to the original state, at this time, the first elastic part 3 generates an upward pushing force to push the second shell 2 to move, but since the locking ball 8 is squeezed out and clamped in the wide groove at the lower part of the upper shell 101, the second shell 2 is limited and constrained, as shown in the figure, the second shell 2 cannot continue to move upward, so the self-locking function is formed. Figure 2

[0056] The memory alloy pin extractor in the application improves the downward movement stroke of the pin shaft through the setting of the second elastic part and the third elastic part, and the driving force is also greatly improved by the two elastic parts. In addition, the setting of the locking ball limits and fixes the first elastic part when it wants to return to the original type, realizes the self-locking, ensures the reliability of the pin extraction process, and has good application prospect and use value as a whole.

[0057] ​​Those skilled in the art can easily understand that the above description is only the preferred embodiment of the present application, and is not intended to limit the present application. Any modification, equivalent replacement and improvement made within the spirit and principle of the present application shall be included in the protection scope of the present application.

Claims

1. A memory alloy pin extractor characterized in that, The first shell, the second shell, the first elastic piece, the second elastic piece, the third elastic piece, the pin shaft and the heating sheet are included. The second shell is arranged in the first shell, the second elastic piece is sleeved on the outer periphery of the second shell, one end of the second elastic piece abuts against the second shell, and the other end abuts against the first shell, and the second elastic piece is in a compressed state in an initial state. One end of the pin shaft is arranged in the second shell, and the other end of the pin shaft can extend out of the second shell. The third elastic piece is sleeved on the outer periphery of the pin shaft, one end of the third elastic piece abuts against the pin shaft, and the other end of the third elastic piece abuts against the second shell, and the third elastic piece is in a compressed state in an initial state. The second shell is provided with a through hole corresponding to the limiting ball, the limiting ball is arranged in the through hole and can abut against the pin shaft, when the second shell drives the limiting ball to move downward to an unblocked state, the third elastic piece pushes the pin shaft to move downward, the conical surface below the pin shaft extrudes the limiting ball to the side, unblocks the pin shaft, and then the limiting ball is clamped in the wide groove of the first shell to form limiting and blocking of the second shell, and the second shell forms self-locking.

2. The memory alloy pin extractor of claim 1, wherein, The plane, at which the pin shaft abuts against the limiting ball, is neither parallel to the vertical direction nor parallel to the horizontal direction.

3. The memory alloy pin extractor of claim 1, wherein, The pin shaft includes a first limiting part, and the third elastic piece and the limiting ball can be limited.

4. The memory alloy pin extractor of claim 1, wherein, The second shell includes a second limiting part, and the second elastic piece can be limited. The second shell is provided with a thread outside the second shell corresponding to the pressing screw, so that the pressing screw is connected with the second shell.

5. The memory alloy pin remover of claim 1, wherein, The pressing screw is connected to one end of the pin shaft, which can extend out of the second shell.

6. The memory alloy pin extractor of any one of claims 1-5, wherein, The first shell includes an upper shell, a lower shell and a connecting piece, and the upper shell and the lower shell are connected through the connecting piece.

7. The memory alloy pin extractor of any one of claims 1-5, wherein, The plane, at which the pin shaft abuts against the limiting ball, is a circular arc surface.

8. The memory alloy pin extractor of claim 7, wherein, The first shell is provided with a first accommodating groove corresponding to the heating sheet, so that the heating sheet can be accommodated in the first accommodating groove.

9. The memory alloy pin extractor of any one of claims 1-5, wherein, The second shell includes a third limiting part, which is located at the bottom of the second shell and has a volume matched with the first accommodating groove, so that the third limiting part can be partially accommodated in the first accommodating groove. The second shell is provided with a second accommodating groove corresponding to the first elastic piece, and the first elastic piece is partially accommodated in the second accommodating groove.

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