CN215280380U

CN215280380U - Battery enclosure clamp

Info

Publication number: CN215280380U
Application number: CN202120764355.3U
Authority: CN
Inventors: 王洪伟; 陈超; 吕豪杰; 刘祥哲
Original assignee: Kunshan Bao Innovative Energy Technology Co Ltd
Current assignee: Kunshan Bao Innovative Energy Technology Co Ltd
Priority date: 2021-04-14
Filing date: 2021-04-14
Publication date: 2021-12-24
Anticipated expiration: 2031-04-14

Abstract

The utility model relates to a battery manufacturing technology field specifically relates to a battery enclosure anchor clamps, and it includes mounting, moving part, compresses tightly piece and elastic component, compress tightly that the piece is movably set up in the moving part, the elastic component supports the moving part with compress tightly between the piece, so that it is close to compress tightly the piece thereby the mounting presss from both sides tight battery case in advance, the moving part is constructed as can be close to the mounting, with the compression the movable allowance of elastic component. The application provides a battery enclosure anchor clamps have clamping state and final clamping state in advance, and adjustable battery case's position under the clamping state in advance makes battery case clamping position accurate, and battery case's middle part is flattened when guaranteeing final clamping state, has both avoided battery case's opening part to warp, solves the problem of the easy light leak of seam position department of battery case and top cap.

Description

Battery enclosure clamp

Technical Field

The application relates to the technical field of battery manufacturing, in particular to a battery enclosure clamp.

Background

The outer case of the battery generally includes a case body having an opening formed at one end thereof to receive the jelly roll, and a top cap covering the opening of the case body and sealed therein by laser welding to enclose the jelly roll.

The casing and the top cap of battery are when laser welding, and the easy light leak of seam position department of casing and top cap, and the light leak can burn to lose and roll up the inside and lead to rolling up a core short circuit of book. Therefore, the middle of the battery shell needs to be clamped before welding so as to prevent the middle of the battery shell from arching and causing the deformation of the opening of the battery shell, thereby avoiding the light leakage at the joint.

SUMMERY OF THE UTILITY MODEL

The present application aims to provide a battery enclosure clamp to solve the problem of easy light leakage at the seam position of a battery shell and a top cover in the prior art.

The embodiment of the application is realized as follows:

in a first aspect, embodiments of the present application provide a battery enclosure clamp, which includes a fixed member, a movable member, a pressing member movably disposed on the movable member, and an elastic member supported between the movable member and the pressing member, so that the pressing member approaches the fixed member to pre-clamp a battery case, and the movable member is configured to approach the fixed member to compress a movement margin of the elastic member.

The application provides a battery enclosure anchor clamps have and press from both sides tight state and final clamping state in advance, utilize the elastic component to order about to compress tightly a tight cell casing in advance, and the frictional force that the cell casing received this moment is less, and cell casing's position can be adjusted, makes the moving part be close to the movable allowance of mounting with compression elastic component after the adjustment is accomplished to make and compress tightly the unable removal of piece and finally press from both sides tight cell casing. This battery enclosure anchor clamps simple structure, extensive applicability, can both realize pressing from both sides tightly in advance and finally press from both sides tightly to multiple specification and dimension's battery, the position of adjustable battery case under the tight state of clamp in advance, it is accurate to make battery case clamping position, battery case's middle part is flattened when guaranteeing final tight state, both avoid battery case's opening part to warp, the problem of the easy light leak of seam position department of solution battery case and top cap, make battery case and inside book core compress tightly again, it leads to the positioning failure to avoid inside book core to rock in the battery case.

In one embodiment of the present application, a guide rod is formed on the movable member, and the guide rod is slidably disposed through the pressing member;

an auxiliary pressure plate is formed at the tail end of the guide rod, and a channel for accommodating the auxiliary pressure plate is formed on the pressing piece.

In the technical scheme, the pressing piece is stable in movement, and the auxiliary pressing plate plays a role in preventing the pressing piece from being separated from the guide rod.

In one embodiment of the present application, a surface of the auxiliary pressing plate is configured to be flush with a surface of the pressing member adjacent to the battery case when the elastic member is compressed to lose the allowance of movement.

In the technical scheme, when the clamping is performed in advance, the auxiliary pressure plate is retracted into the channel, so that the contact area between the auxiliary pressure plate and the battery shell is reduced, the friction force is reduced, and the position of the battery shell is convenient to adjust; when the elastic component lost the play allowance, the battery casing was finally pressed from both sides tightly, and the surface of supplementary clamp plate pastes tight battery casing just this moment, increase and battery casing's area of contact to increase battery casing's lifting surface area, improve and press from both sides tight effect, further solve the problem of the easy light leak of seam position department of battery casing and top cap.

In an embodiment of the application, one side of the pressing member, which is far away from the moving member, is formed with a first fixing surface and a second fixing surface, the first fixing surface is located at one end of the second fixing surface, the first fixing surface is used for bearing the bottom surface of the battery shell, and the second fixing surface is used for abutting against one side surface of the battery shell.

In above-mentioned technical scheme, compress tightly the first fixed surface and the second fixed surface of piece and fix a position battery case respectively in two directions, and the laminating of second fixed surface prevents battery case's side hunch-up in battery case's side, effectively prevents that battery case's opening part from warping and leading to the seam position department light leak of battery case and top cap.

In an embodiment of the present application, a pre-tightening rubber strip is disposed at an end of the second fixing surface away from the first fixing surface.

In the technical scheme, one end, far away from the first fixing surface, of the second fixing surface is close to the opening of the battery shell, and the pre-tightening rubber strip ensures that the part near the opening of the battery shell is clamped tightly, so that light leakage at the joint position of the battery shell and the top cover is further prevented.

In an embodiment of this application, the mounting includes third stationary plane and fourth stationary plane, the third stationary plane is located the one end of fourth stationary plane, the third stationary plane is used for accepting battery case's bottom surface, the fourth stationary plane is used for supporting tight battery case's another side.

In the technical scheme, the third fixing surface and the fourth fixing surface of the fixing piece are used for positioning the battery shell in two directions respectively, the fourth fixing surface is attached to the side face of the battery shell to prevent the side face of the battery shell from arching, and the light leakage at the seam position of the battery shell and the top cover caused by deformation of the opening of the battery shell is effectively prevented.

In an embodiment of the present application, the fixing member further includes a battery case adhesion layer, the battery case adhesion layer is located on the fourth fixing surface, the length of the battery case adhesion layer is smaller than the length of the fourth fixing surface, and the width of the battery case adhesion layer is smaller than the width of the fourth fixing surface.

In above-mentioned technical scheme, when battery casing laminating layer laminating was on battery casing, battery casing laminating layer can avoid battery casing's edges and corners position to reduce battery casing's edges and corners position atress, prevent that battery casing's edges and corners warp.

In an embodiment of the present application, the fixing member further includes a bonding plate, the bonding plate is disposed on the fourth fixing surface, and the battery case attachment layer is bonded to the bonding plate.

In the above technical scheme, the battery shell attaching layer is indirectly bonded to the fourth fixing surface through the bonding plate, so that the battery shell attaching layer is convenient to replace.

In one embodiment of the present application, the thickness of the battery case lamination layer gradually decreases from the middle to the edge and forms a curved surface.

In the technical scheme, the thickness of the battery shell laminating layer is gradually reduced from the middle to the edge so as to increase the pressure applied to the middle of the battery shell, so that the middle of the battery shell compresses the winding core inside the battery shell, and the middle of the battery shell is prevented from arching and deforming.

In an embodiment of the present application, a pre-tightening rubber strip is disposed at an end of the fourth fixing surface far away from the third fixing surface.

In the technical scheme, one end, far away from the third fixing surface, of the fourth fixing surface is close to the opening of the battery shell, and the pre-tightening rubber strip ensures that the part near the opening of the battery shell is clamped tightly, so that light leakage at the joint position of the battery shell and the top cover is further prevented.

Drawings

In order to more clearly illustrate the technical solutions of the embodiments of the present application, the drawings that are required to be used in the embodiments will be briefly described below, it should be understood that the following drawings only illustrate some embodiments of the present application and therefore should not be considered as limiting the scope, and for those skilled in the art, other related drawings can be obtained from the drawings without inventive effort.

Fig. 1 is a schematic structural view of a battery enclosure clamp provided in an embodiment of the present application;

fig. 2 is a diagram of a final clamping state of a battery enclosure clamp provided by an embodiment of the present application;

fig. 3 is a schematic perspective view of the movable member and the pressing member according to the embodiment of the present application;

FIG. 4 is a front view of the moveable member and the compression member provided in accordance with an embodiment of the present application;

FIG. 5 is a top view of the moveable member and the compression member provided in accordance with an embodiment of the present application;

FIG. 6 is a left side view of the moveable member and the compression member provided in accordance with an embodiment of the present application;

fig. 7 is a schematic perspective view of a fixing member according to an embodiment of the present application;

FIG. 8 is a front view of a mount provided in accordance with an embodiment of the present application;

FIG. 9 is a top view of a mount provided in accordance with an embodiment of the present application;

FIG. 10 is a right side view of a mount provided in accordance with an embodiment of the present application;

fig. 11 is a schematic view of the fit between the abutting surface and the battery case according to the embodiment of the present application.

Icon: 1-a battery case; 2-a top cover; 100-a fastener; 110-a third fixation surface; 120-a fourth fixation surface; 130-battery case lamination layer; 140-a bonding plate; 200-a movable member; 210-a guide bar; 220-auxiliary pressure plate; 300-a compression member; 310-a first fixation surface; 320-a second fixation surface; 330-channel; 400-an elastic member; 500-pre-tightening the rubber strip; 600-cylinder.

Detailed Description

In order to make the objects, technical solutions and advantages of the embodiments of the present application clearer, the technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the drawings in the embodiments of the present application, and it is obvious that the described embodiments are some embodiments of the present application, but not all embodiments. The components of the embodiments of the present application, generally described and illustrated in the figures herein, can be arranged and designed in a wide variety of different configurations.

Thus, the following detailed description of the embodiments of the present application, presented in the accompanying drawings, is not intended to limit the scope of the claimed application, but is merely representative of selected embodiments of the application. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present application.

It should be noted that: like reference numbers and letters refer to like items in the following figures, and thus, once an item is defined in one figure, it need not be further defined and explained in subsequent figures.

In the description of the present application, it should be noted that if the terms "center", "upper", "lower", "left", "right", "vertical", "horizontal", "inner", "outer", etc. are used for indicating the orientation or positional relationship based on the orientation or positional relationship shown in the drawings or the orientation or positional relationship which is usually placed when the product of the application is used, the description is only for convenience and simplicity, and the indication or suggestion that the referred device or element must have a specific orientation, be constructed in a specific orientation and be operated, and thus, should not be construed as limiting the present application. Furthermore, the appearances of the terms "first," "second," and the like in the description herein are only used for distinguishing between similar elements and are not intended to be construed as indicating or implying relative importance.

Furthermore, the terms "horizontal", "vertical" and the like when used in the description of the present application do not require that the components be absolutely horizontal or overhanging, but may be slightly inclined. For example, "horizontal" merely means that the direction is more horizontal than "vertical" and does not mean that the structure must be perfectly horizontal, but may be slightly inclined.

In the description of the present application, it should also be noted that, unless otherwise explicitly stated or limited, the terms "disposed," "mounted," "connected," and "connected" should be interpreted broadly, e.g., as being fixedly connected, detachably connected, or integrally connected; can be mechanically or electrically connected; they may be connected directly or indirectly through intervening media, or they may be interconnected between two elements. The specific meaning of the above terms in the present application can be understood in a specific case by those of ordinary skill in the art.

Examples

At present, a common battery, such as a lithium battery, a winding core, an electrolyte, and the like, needs to be loaded from an opening of a battery case, and then the opening of the battery case is sealed by a top cover, which is generally welded at a seam position of the battery case and the top cover by laser welding.

Due to manufacturing tolerance of the winding core, uneven electrolyte coating or filling and the like, the middle part of the battery shell is easy to be extruded and arched, and the opening of the battery shell is also deformed, so that light leakage is caused at the joint position of the battery shell and the top cover. When there is the light leak problem, if laser welding at the seam, easily burn the inside book core.

At present, in order to solve the problem of light leakage, the battery shell is clamped before welding so as to flatten the middle part of the battery shell, thereby avoiding the deformation of the opening of the battery shell. However, the existing clamp is inconvenient to adjust the placement position of the battery shell when in use, sometimes avoids the poor deformation effect of the battery shell, and still has the problem of easy light leakage at the joint position of the battery shell and the top cover.

The application provides a battery enclosure clamp for solve the problem of the easy light leak of seam position department of battery case and top cap.

As shown in fig. 1, the battery enclosure fixture includes a stationary member 100, a movable member 200, a pressing member 300, and an elastic member 400, the pressing member 300 being movably disposed at the movable member 200, the elastic member 400 being supported between the movable member 200 and the pressing member 300, the movable member 200 being configured to be movable toward or away from the stationary member 100.

The battery case 1 is placed between the fixing member 100 and the pressing member 300, two opposite side surfaces of the battery case 1 correspond to the fixing member 100 and the pressing member 300, respectively, and the bottom surface of the battery case 1 is opposite to the top cover 2 at the opening of the battery case 1. Under the supporting action of elastic component 400, pressing component 300 and mounting 100 cooperate in order to press from both sides tight battery case 1 in advance, and elastic component 400 can stretch out and draw back this moment, makes pressing component 300 keep certain allowance for movement, and the frictional force that battery case 1 received is little, and battery case 1 still can move about in order to conveniently adjust the position of placing of battery case 1.

After the adjustment, the movable member 200 is close to the fixed member 100, and the movable member 200 compresses the movement allowance of the elastic member 400, so that the elastic member 400 cannot stretch or contract again, and further the movement allowance of the pressing member 300 is eliminated, and the pressing member 300 cannot move again, thereby achieving the clamping state shown in fig. 2, and at this time, the fixed member 100, the battery case 1, the pressing member 300, and the movable member 200 are relatively fixed, thereby finally clamping the battery case 1.

The application provides a battery enclosure anchor clamps through pressing from both sides tightly in advance and finally pressing from both sides tightly, improves the degree of accuracy of the position of placing of battery casing 1, guarantees the effect of flattening of battery casing 1 to solve the problem of the easy light leak of seam position department of battery casing 1 and top cap 2.

The structure is shown in fig. 3, one side of the movable member 200 is used for connecting a linear driving mechanism for manual or mechanical driving, and the other side of the movable member 200 is used for connecting the pressing member 300.

The linear driving mechanism can be various, such as an electric cylinder, a hydraulic cylinder, a linear module, the air cylinder 600, and the like, the number of the linear driving mechanism is at least one, in this embodiment, the linear driving mechanism is four air cylinders 600, and the four air cylinders 600 synchronously drive the movable member 200.

As shown in fig. 4 and 5, the movable member 200 is configured as a rectangular body, the output ends of the four cylinders 600 are all connected with the surface of the movable member 200 on the side away from the pressing member 300, and the output ends of the four cylinders 600 are all distributed on the surface, and optionally, the output ends of the four cylinders 600 are connected at four corners of the surface.

A guide rod 210 is formed on one side of the movable member 200 close to the pressing member 300, the guide rod 210 is slidably inserted into the pressing member 300, an auxiliary pressure plate 220 is formed at the end of the guide rod 210, and a passage 330 for accommodating the auxiliary pressure plate 220 is formed in the pressing member 300. The auxiliary pressure plate 220 increases the size of the end of the guide bar 210, and serves to prevent the pressing member 300 from being separated from the guide bar 210.

In order to further improve the stability of the pressing member 300, the guide rods 210 are configured in a plurality, and as shown in fig. 4 and 5, the plurality of guide rods 210 are uniformly connected to the pressing member 300.

In some embodiments, the auxiliary pressure plate 220 is configured to: when the elastic member 400 is compressed to lose the allowance of movement, the surface of the auxiliary pressure plate 220 is flush with the surface of the pressing member 300 close to the battery case 1.

As shown in fig. 6, the pressing member 300 has a channel 330, which reduces the contact area between the pressing member 300 and the battery case 1, and when the battery case 1 is in the pre-clamping state, the friction force applied to the battery case 1 is small, so that the position of the battery case 1 can be adjusted by applying a relatively small external force, and the effect of conveniently adjusting the position of the battery case 1 is achieved.

In the process of transition from the pre-clamping state to the final clamping state, the movable element 200 approaches the fixed element 100, that is, the movable element 200 moves towards the pressing element 300, the elastic element 400 is gradually compressed, the auxiliary pressing plate 220 moves along the channel 330 to approach the side surface of the battery shell 1 along with the movement of the movable element 200, when the elastic element 400 loses the movement margin, the battery shell 1 is finally clamped, the auxiliary pressing plate 220 clings to the side surface of the battery shell 1, the stress area of the battery shell 1 is increased, and therefore the clamping effect is improved.

In order to better position the battery case 1, the pressing member 300 is formed with a first fixing surface 310 and a second fixing surface 320, the first fixing surface 310 is located at one end of the second fixing surface 320, the first fixing surface 310 is used for receiving the bottom surface of the battery case 1, and the second fixing surface 320 is used for abutting against the side surface of the battery case 1.

The angle of the first fixing face 310 and the second fixing face 320 is greater than 0 ° and less than 180 ° in order to match different shapes of the battery case 1.

In the present embodiment, the first fixing surface 310 and the second fixing surface 320 are perpendicular to match the battery case 1 having the side and bottom surfaces perpendicular.

Accordingly, as shown in fig. 7, 8 and 9, the fixing member 100 is formed with a third fixing surface 110 and a fourth fixing surface 120, the third fixing surface 110 is located at one end of the fourth fixing surface 120, the third fixing surface 110 and the first fixing surface 310 together receive the ground of the battery case 1, and the fourth fixing surface 120 and the second fixing surface 320 are parallel.

The angle of the third fixing surface 110 and the fourth fixing surface 120 is greater than 0 ° and less than 180 ° in order to match differently shaped battery cases 1.

In the present embodiment, the third fixing surface 110 and the fourth fixing surface 120 are perpendicular to match the battery case 1 with the side and bottom surfaces perpendicular.

Referring to fig. 1 again, the fixing element 100 and the pressing element 300 are respectively L-shaped, and two L-shaped members are disposed oppositely, wherein two flush surfaces are the first fixing surface 310 and the third fixing surface 110, and two opposite surfaces are the second fixing surface 320 and the fourth fixing surface 120. After the battery case 1 is placed between the fixing member 100 and the pressing member 300, the bottom surface of the battery case 1 is attached to the first fixing surface 310 and the third fixing surface 110, two side surfaces of the battery case 1 correspond to the second fixing surface 320 and the fourth fixing surface 120, respectively, the elastic member 400 drives the second fixing surface 320 to be attached to the side surface of the battery case 1, and presses the battery case 1 to the fourth fixing surface 120, and then the movable member 200 moves toward the fixing member 100, compresses the elastic member 400, and causes the auxiliary pressure plate 220 to be attached to the side surface of the battery case 1.

In order to ensure that the battery case 1 and the winding core inside the battery case are pressed and fixed, and further prevent the middle of the battery case 1 from arching, the fixing member 100 further includes a battery case adhesion layer 130, as shown in fig. 10, the battery case adhesion layer 130 is located on the fourth fixing surface 120, the length of the battery case adhesion layer 130 is smaller than that of the fourth fixing surface 120, and the width of the battery case adhesion layer 130 is smaller than that of the fourth fixing surface 120. In other words, a projection of the battery case attachment layer 130 on the fourth fixing surface 120 is smaller than the fourth fixing surface 120, and an edge of the projection of the battery case attachment layer 130 on the fourth fixing surface 120 does not coincide with an edge of the fourth fixing surface 120.

When pressing from both sides tight battery case 1, battery case laminating layer 130 laminates in the side of battery case 1, and battery case laminating layer 130 avoids the edges and corners position of battery case 1 to reduce the edges and corners position atress of battery case 1, prevent that the edges and corners of battery case 1 from warping.

In some embodiments, further, as shown in fig. 11, the thickness of the battery case adhesion layer 130 gradually decreases from the middle to the edge and forms a curved surface, so that the pressure applied to the middle of the battery case 1 is greater than the pressure applied to the corners of the battery case 1, further preventing the middle of the battery case 1 from arching and deforming, and ensuring that the middle of the battery case 1 presses the winding core therein.

In some embodiments, the battery case bonding layer 130 is made of an elastic material, and the middle of the battery case bonding layer 130 is thicker to increase the pressure applied to the middle portion of the battery case 1. When the middle of the battery case bonding layer 130 is compressed by being pressed, the edge of the battery case bonding layer 130 is close to the side surface of the battery case 1 to further press the battery case 1, thereby improving the clamping effect.

In order to facilitate replacement of the battery case laminating layer 130, the fixing member 100 further includes a bonding plate 140, the bonding plate 140 is disposed on the fourth fixing surface 120, and the battery case laminating layer 130 is bonded to the bonding plate 140.

In some embodiments, the bonding plate 140 is configured to be detachably coupled to the fourth fixing surface 120 so that the bonding plate 140 is detached to replace the battery case attachment layer 130.

In order to ensure that the part near the opening of the battery shell 1 is clamped, one end of the second fixing surface 320, which is far away from the first fixing surface 310, is provided with a pre-tightening adhesive tape 500, one end of the second fixing surface 320, which is far away from the first fixing surface 310, is close to the opening of the battery shell 1, and the pre-tightening adhesive tape 500 ensures that the part near the opening of the battery shell 1 is clamped, so that light leakage at the position of the battery shell 1 and a joint position is further prevented.

Similarly, one end of the fourth fixing surface 120, which is far away from the third fixing surface 110, is provided with a pre-tightening rubber strip 500, one end of the fourth fixing surface 120, which is far away from the third fixing surface 110, is close to the opening of the battery case 1, and the pre-tightening rubber strip 500 ensures that the vicinity of the opening of the battery case 1 is clamped, so that light leakage at the battery case 1 and the joint position is further prevented.

The pre-tightening rubber strips 500 on the second fixing surface 320 and the fourth fixing surface 120 respectively abut against the openings on the two side surfaces of the battery shell 1, and the pre-tightening rubber strips and the openings are matched to further prevent the deformation of the opening of the battery shell 1, so that the problem that the joint position of the battery shell 1 and the top cover 2 is easy to leak light is solved.

The above description is only a preferred embodiment of the present application and is not intended to limit the present application, and various modifications and changes may be made by those skilled in the art. Any modification, equivalent replacement, improvement and the like made within the spirit and principle of the present application shall be included in the protection scope of the present application.

Claims

1. A battery enclosure clamp, comprising:

the battery clamping device comprises a fixed piece, a movable piece, a pressing piece and an elastic piece, wherein the pressing piece is movably arranged on the movable piece, the elastic piece is supported between the movable piece and the pressing piece, so that the pressing piece is close to the fixed piece to pre-clamp the battery shell, and the movable piece is constructed to be close to the fixed piece to compress the movable allowance of the elastic piece.

2. The battery enclosure holder of claim 1, wherein the movable member has a guide rod formed thereon, the guide rod being slidably disposed through the pressing member;

3. The battery enclosure fixture of claim 2, wherein a surface of the auxiliary pressure plate is configured to be flush with a face of the pressing member adjacent to the battery case when the elastic member is compressed to lose a play margin.

4. The battery enclosure clamp of claim 3, wherein a side of the compressing member away from the movable member is formed with a first fixing surface and a second fixing surface, the first fixing surface is located at one end of the second fixing surface, the first fixing surface is configured to receive a bottom surface of the battery case, and the second fixing surface is configured to abut against one side surface of the battery case.

5. The battery enclosure clamp of claim 4, wherein an end of the second securing surface distal from the first securing surface is provided with a pre-tightening strip.

6. The battery capsule holder of any of claims 2-5, wherein the fixture comprises a third fixing surface and a fourth fixing surface, the third fixing surface is located at one end of the fourth fixing surface, the third fixing surface is used for receiving the bottom surface of the battery case, and the fourth fixing surface is used for abutting against the other side surface of the battery case.

7. The battery enclosure clamp of claim 6, wherein the fixture further comprises a battery case engaging layer, the battery case engaging layer is located at the fourth securing surface, and the battery case engaging layer has a length less than the length of the fourth securing surface and a width less than the width of the fourth securing surface.

8. The battery enclosure clamp of claim 7, wherein the fixture further comprises a bonding plate disposed at the fourth mounting surface, the battery housing conforming layer being bonded to the bonding plate.

9. The battery enclosure clamp of claim 7, wherein the battery housing conforming layer tapers in thickness from a middle to an edge and forms a curved surface.

10. The battery enclosure clamp of claim 6, wherein an end of the fourth securing surface distal from the third securing surface is provided with a pre-tightening strip.