Auxiliary wire stripping mechanism for ignition head processing
By designing an auxiliary wire stripping mechanism for ignition head processing, and utilizing replacement modules and locking components to achieve automatic blade replacement and secure fixation, the problems of wire stripping blade wear and edge dulling are solved, thereby improving wire stripping efficiency and stability.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- LIUYANG TOP ELECTRONIC PROCESSING CO LTD
- Filing Date
- 2025-08-15
- Publication Date
- 2026-08-04
AI Technical Summary
In the current production process of electric igniters, wear and dulling of the wire stripping blades lead to unstable wire stripping quality, and the replacement process is cumbersome, affecting production efficiency.
An auxiliary wire stripping mechanism for ignition head processing was designed. It adopts a replacement module and a locking component. The motor drives a bidirectional lead screw to move the tool holder, realizing automatic blade replacement and locking positioning, simplifying the replacement process.
It improves the efficiency of wire stripping, reduces blade replacement time, and ensures the stability and accuracy of wire stripping operations.
Smart Images

Figure CN224596072U_ABST
Abstract
Description
Technical Field
[0001] This utility model relates to the field of ignition head processing technology, specifically to an auxiliary wire stripping mechanism for ignition head processing. Background Technology
[0002] An electric igniter is an electrically triggered ignition device used in fireworks, firecrackers, and other pyrotechnic products. It mainly consists of a resistance wire, igniter, insulating shell, and wires. It works by using electrical energy (usually low-voltage direct current) flowing through the built-in resistance wire (bridge wire or heating wire) to generate heat, which ignites the igniter wrapped around it. The resulting flame or spark then ignites the connected firework body. Compared to traditional open flame ignition methods, electric igniters have advantages such as safer operation, controllable ignition timing, and ease of remote synchronous control.
[0003] In the production of existing electric igniters, to ensure reliable conductivity, production efficiency, and safety, wire stripping equipment is required to precisely remove the insulation layer at the end of the wire. This ensures a reliable electrical connection between the metal conductor of the wire and components such as electrodes to transmit current. However, due to the diverse specifications of the wires in electric igniters and the differences in insulation materials (such as PVC and rubber), the wire stripping blades are prone to wear and dulling over long-term use, affecting the stripping quality. Therefore, the blades need to be replaced periodically. However, since the blades are generally directly mounted on the blade holder using bolts or other fasteners, the disassembly and assembly process is not only cumbersome but also prone to wear of the mounting holes and displacement of the positioning reference due to repeated disassembly and assembly, thus affecting the installation accuracy of the blades. Based on this, an auxiliary wire stripping mechanism for igniter processing is now provided, which can eliminate the drawbacks of the existing device. Utility Model Content
[0004] The purpose of this invention is to provide an auxiliary wire stripping mechanism for ignition head processing, so as to solve the problems in the background art.
[0005] To achieve the above objectives, this utility model provides the following technical solution:
[0006] An auxiliary wire stripping mechanism for ignition head processing includes a base, a receiving box slidably connected inside the base, a support seat mounted on the top of the base, a guide rail fixedly connected to one end of the support seat, the guide rail being located above the receiving box, two tool holders symmetrically slidably sleeved on the outer wall of the guide rail, and multiple blades equidistantly arranged laterally at the ends of the two tool holders that are close to each other, and a replacement module for convenient replacement of the blades is provided on the tool holder;
[0007] The replacement module includes:
[0008] Multiple support plates are laterally and equidistantly slidably connected inside the tool holder. Two guide plates are symmetrically fixed to the outer walls of each of the multiple support plates. The multiple support plates are located above multiple blades. A linear slot is provided at the junction of the tool holder and the support plates and guide plates to allow the support plates and guide plates to slide. A connecting plate is fixedly connected to the bottom end of each of the multiple support plates. The connecting plate is located on one side of the blade. The blade is fixedly connected to the connecting plate by bolts and nuts.
[0009] Based on the above technical solutions, this utility model also provides the following optional technical solutions:
[0010] In one alternative embodiment, the replacement module further includes:
[0011] A locking assembly mounted on the tool holder;
[0012] The engagement component includes:
[0013] Multiple connecting push rods are laterally and equidistantly slidably connected inside the tool holder. The multiple connecting push rods are respectively located above multiple support plates. The bottom end of each of the multiple connecting push rods is fixedly connected to a positioning block. One end of the positioning block has an outer wall that is beveled. The positioning block penetrates into the interior of the support plate. The top end of each of the multiple connecting push rods is fixedly connected to a lifting slider. One end of the lifting slider has an outer wall that is beveled.
[0014] The connecting push rod is equipped with a first reset component that drives the positioning block to reset.
[0015] The tool holder is equipped with a lifting component for pushing the lifting slider upward;
[0016] The tool holder is provided with a locking component for pressing and locking the lifting slider;
[0017] The guide plate is equipped with a pushing component for displacing the guide plate.
[0018] In one alternative: the first reset component is a second spring sleeved on the outer wall of the connecting push rod, one end of the second spring is in contact with the inner wall of the tool holder, and the other end of the second spring is in contact with the outer wall of the positioning block.
[0019] In one alternative embodiment, the lifting assembly includes:
[0020] A lifting push plate is slidably connected inside the tool holder. The lifting push plate is slidably sleeved on the outer wall of multiple connecting push rods. Two fixed push blocks are symmetrically fixedly connected to the bottom end of the lifting push plate. A movable push frame is provided at the end of the tool holder away from the support base. The movable push frame is C-shaped and penetrates the tool holder to contact the outer wall of the fixed push block. The outer wall of the fixed push block at the contact position with the movable push frame is inclined. Two limiting sliders are symmetrically fixedly connected to the outer wall of the movable push frame. A limiting groove is provided at the contact position between the tool holder and the movable push frame and the limiting sliders to allow the movable push frame and the limiting sliders to slide.
[0021] In one alternative embodiment, the locking component includes:
[0022] A movable pressure plate is slidably connected inside the tool holder. The movable pressure plate contacts the outer wall of the lifting slider. The movable pressure plate and the outer wall of the lifting slider are in close contact with each other. A knurled bolt is provided at the end of the tool holder away from the support seat. The knurled bolt passes through the tool holder and contacts the outer wall of the movable pressure plate. The tool holder is threadedly connected to the knurled bolt.
[0023] In one alternative embodiment, the push component includes:
[0024] A limiting slide rod is provided at one end of the guide pressure plate. The limiting slide rod is in contact with the outer wall of the guide pressure plate. A limiting baffle is fixedly connected to the end of the limiting slide rod away from the guide pressure plate. Both the limiting slide rod and the limiting baffle are slidably connected to the tool holder.
[0025] A second reset component is provided on the limiting baffle.
[0026] In one alternative: the second reset component is a first spring disposed at the end of the limiting baffle away from the limiting slide rod, one end of the first spring being in contact with the outer wall of the limiting baffle, and the other end of the first spring being in contact with the inner wall of the tool holder.
[0027] In one alternative embodiment: a motor is mounted on the top of the support base, and a bidirectional lead screw is fixedly connected to the drive end of the motor. The bidirectional lead screw is located inside the support base and is rotatably connected to the support base via an end shaft. Two movable frames are symmetrically sleeved on the outer wall of the bidirectional lead screw. Both movable frames are threadedly connected to the bidirectional lead screw and slidably connected to the support base. Both movable frames are C-shaped and are fixedly connected to two tool holders respectively. The guide rail is located inside the two movable frames.
[0028] Compared with the prior art, the beneficial effects of this utility model are as follows:
[0029] This invention, through a replacement module, can quickly release the locking and locking limit of the blade when the blade is worn or the cutting edge is dull, and push the blade to automatically and slowly pop out. Then, multiple blades can be replaced in sequence, which makes it convenient for operators to replace multiple blades. After the blade replacement is completed, the blade can be fixed in place by automatic locking, which effectively ensures the stable performance of the wire stripping operation, thereby effectively reducing the time required for blade replacement and further improving the efficiency of wire stripping. Attached Figure Description
[0030] Figure 1 This is a schematic diagram of the structure of this utility model.
[0031] Figure 2 This is a schematic diagram of the connection structure between the movable frame and the bidirectional lead screw of this utility model.
[0032] Figure 3 This is a schematic diagram of the internal structure of the tool holder of this utility model.
[0033] Figure 4 This is a schematic diagram of the internal structure of the lifting push plate of this utility model.
[0034] Figure 5 For the present utility model Figure 3 A magnified schematic diagram of the structure at point A in the diagram.
[0035] Figure reference numerals: 1. Base; 201. Movable pressure plate; 202. Knurled bolt; 203. Movable push frame; 204. Support plate; 205. Guide pressure plate; 206. Lifting slider; 207. Connecting push rod; 208. Positioning block; 209. Lifting push plate; 2010. Fixed push block; 2011. First spring; 2012. Limiting slider; 2013. Second spring; 2014. Limiting slide rod; 2015. Limiting baffle; 3. Support seat; 4. Receiving box; 5. Knife holder; 6. Blade; 7. Motor; 8. Movable frame; 9. Two-way lead screw; 10. Guide rail. Detailed Implementation
[0036] To make the objectives, technical solutions, and advantages of this utility model clearer, the present utility model will be further described in detail below with reference to the accompanying drawings and embodiments.
[0037] In one embodiment, such as Figures 1-5As shown, the auxiliary wire stripping mechanism for ignition head processing includes a base 1, a receiving box 4 slidably connected inside the base 1, a support seat 3 mounted on the top of the base 1, a guide rail 10 fixedly connected to one end of the support seat 3, the guide rail 10 being located above the receiving box 4, two tool holders 5 symmetrically slidably sleeved on the outer wall of the guide rail 10, multiple blades 6 being equidistantly arranged laterally at the ends of the two tool holders 5 that are close to each other, a motor 7 mounted on the top of the support seat 3, a bidirectional lead screw 9 fixedly connected to the drive end of the motor 7, the bidirectional lead screw 9 being located inside the support seat 3, the bidirectional lead screw 9 being rotatably connected to the support seat 3 through an end shaft, two movable frames 8 symmetrically sleeved on the outer wall of the bidirectional lead screw 9, both movable frames 8 being threadedly connected to the bidirectional lead screw 9, both movable frames 8 being slidably connected to the support seat 3, both movable frames 8 being C-shaped, both movable frames 8 being fixedly connected to the two tool holders 5 respectively, the guide rail 10 being located inside the two movable frames 8, and a replacement module for convenient replacement of the blades 6 being provided on the tool holder 5;
[0038] The modules to be replaced include:
[0039] Multiple support plates 204 are laterally and equidistantly slidably connected inside the tool holder 5. Two guide plates 205 are symmetrically fixed to the outer walls of the multiple support plates 204. The multiple support plates 204 are located above the multiple blades 6. A linear slot is provided at the junction of the tool holder 5 with the support plates 204 and the guide plates 205 to allow the support plates 204 and the guide plates 205 to slide. Anti-slip pads are fixedly connected to the side of the two guide plates 205 away from the support plates 204. The anti-slip pads are in contact with the inner wall of the linear slot. A connecting plate is fixedly connected to the bottom of the multiple support plates 204. The connecting plate is located on one side of the blade 6. The blade 6 is fixedly connected to the connecting plate by bolts and nuts.
[0040] In this embodiment, when in use, the start motor 7 drives the bidirectional lead screw 9 to rotate. At this time, the two moving frames 8 are connected by threads to the bidirectional lead screw 9 and drive the two blade holders 5 to slide along the outer wall of the guide rail 10 respectively. At the same time, the blades 6 move synchronously under the drive of the blade holders 5. At this time, by moving away from or closer to each other, the two blade holders 5 can drive multiple blades 6 to cut and strip the wire in sequence.
[0041] When the blade 6 needs to be replaced due to wear and dulling of the cutting edge, the replacement module can release the locking of the blade 6. At the same time, the support plate 204 drives the blade 6 to pop out automatically. Then, the above operation is reversed. In this way, multiple blades 6 can be individually locked and fixed, so as to achieve the purpose of convenient replacement of the blade 6, so as to further improve the efficiency of wire stripping.
[0042] In one embodiment, such as Figures 3-5 As shown, the replacement module also includes:
[0043] A locking assembly is mounted on the tool holder 5;
[0044] The card-connecting components include:
[0045] Multiple connecting push rods 207 are laterally and equidistantly slidably connected inside the tool holder 5. The multiple connecting push rods 207 are located above multiple support plates 204. The bottom end of each of the multiple connecting push rods 207 is fixedly connected to a positioning block 208. One end of the positioning block 208 has an outer wall that is beveled. The positioning block 208 penetrates into the interior of the support plate 204. The top end of each of the multiple connecting push rods 207 is fixedly connected to a lifting slider 206. One end of the lifting slider 206 has an outer wall that is beveled.
[0046] The connecting push rod 207 is equipped with a first reset component that drives the positioning block 208 to reset;
[0047] The tool holder 5 is equipped with a lifting component for pushing the lifting slider 206 upward;
[0048] The tool holder 5 is provided with a locking component for pressing and locking the lifting slider 206;
[0049] The guide plate 205 is provided with a pushing component for pushing the guide plate 205 to move.
[0050] The first reset component is a second spring 2013 sleeved on the outer wall of the connecting push rod 207. One end of the second spring 2013 contacts the inner wall of the tool holder 5, and the other end of the second spring 2013 contacts the outer wall of the positioning block 208. Through the cooperation of the locking component and the first reset component, the support plate 204 can be automatically locked and positioned.
[0051] In one embodiment, such as Figures 1-5 As shown, the lifting assembly includes:
[0052] A lifting push plate 209 is slidably connected inside the tool holder 5. Multiple guide sliders are fixedly connected equidistantly along the inner wall of the lifting push plate 209. A guide groove is provided at the contact point between the connecting push rod 207 and the guide slider for the guide slider to slide. The lifting push plate 209 is slidably sleeved on the outer wall of the multiple connecting push rods 207. Two fixed push blocks 2010 are symmetrically fixedly connected to the bottom end of the lifting push plate 209. A movable push frame 203 is provided at the end of the tool holder 5 away from the support base 3. The movable push frame 203 is C-shaped. The frame 203 penetrates the cutter holder 5 and contacts the outer wall of the fixed push block 2010. The outer wall of the fixed push block 2010 at the junction with the movable push frame 203 is inclined. Two limiting sliders 2012 are symmetrically fixedly connected to the outer wall of the movable push frame 203. A limiting groove is provided at the junction of the cutter holder 5 with the movable push frame 203 and the limiting sliders 2012 for sliding. Through the cooperation between the movable push frame 203 and the fixed push block 2010, the lifting push plate 209 can be pushed to rise stably.
[0053] In one embodiment, such as Figures 1-5 As shown, the locking component includes:
[0054] A movable pressure plate 201 is slidably connected inside the tool holder 5. The movable pressure plate 201 contacts the outer wall of the lifting slider 206. The movable pressure plate 201 and the outer wall of the lifting slider 206 fit together. A knurled bolt 202 is provided at the end of the tool holder 5 away from the support base 3. The knurled bolt 202 passes through the tool holder 5 and contacts the outer wall of the movable pressure plate 201. The tool holder 5 is threadedly connected to the knurled bolt 202. Through the cooperation between the movable pressure plate 201 and the lifting slider 206, the connecting push rod 207 can be locked and fixed when the knurled bolt 202 squeezes and locks the movable pressure plate 201.
[0055] In one embodiment, such as Figures 3-5 As shown, the push component includes:
[0056] A limiting slide rod 2014 is provided at one end of the guide pressure plate 205. The limiting slide rod 2014 is in contact with the outer wall of the guide pressure plate 205. A limiting baffle 2015 is fixedly connected to the end of the limiting slide rod 2014 away from the guide pressure plate 205. Both the limiting slide rod 2014 and the limiting baffle 2015 are slidably connected to the tool holder 5.
[0057] A second reset component is provided on the limit baffle 2015;
[0058] The second reset component is a first spring 2011 located at the end of the limiting baffle 2015 away from the limiting slide bar 2014. One end of the first spring 2011 is in contact with the outer wall of the limiting baffle 2015, and the other end of the first spring 2011 is in contact with the inner wall of the tool holder 5. Through the cooperation of the pushing component and the second reset component, when the locking limit on the support insert 204 is released, the guide pressure plate 205 is pushed to make the support insert 204 automatically and slowly pop out.
[0059] The above embodiment discloses an auxiliary wire stripping mechanism for ignition head processing. In use, the starter motor 7 drives the bidirectional lead screw 9 to rotate. At this time, the two moving frames 8 are connected by threads to the bidirectional lead screw 9 and drive the two tool holders 5 to slide along the outer wall of the guide rail 10 respectively. At the same time, the blades 6 move synchronously under the drive of the tool holders 5. At this time, by moving the two tool holders 5 away from each other or close to each other, multiple blades 6 can be driven to cut and strip the wire in sequence.
[0060] When the blade 6 needs to be replaced due to wear and dulling of the cutting edge, the knurled bolt 202 is rotated to separate from the movable pressure plate 201, thereby releasing the compression lock on the movable pressure plate 201. Then, the movable push frame 203 is pushed to drive the limit slider 2012 to slide along the inner wall of the limit groove. At this time, the two fixed push blocks 2010 push the lifting push plate 209 to rise along the inner wall of the tool holder 5 through the pressure of the movable push frame 203 via the inclined outer wall. At the same time, the lifting slider 206, pushed by the lifting push plate 209, squeezes the movable pressure plate 201 to slide along the inner wall of the tool holder 5 through the inclined outer wall via the inclined outer wall. And through the connecting push rod 207, the positioning block 208 is separated from the inner wall of the support plate 204. At this time, the positioning block 208 retracts by moving the compression second spring 2013, thereby releasing the locking limit on the support plate 204.
[0061] When the positioning block 208 is completely separated from the support plate 204, the first spring 2011 pushes the limiting baffle 2015 to slide along the inner wall of the tool holder 5 through rebound. At the same time, the guide pressure plate 205, through the limiting slide rod 2014, drives the support plate 204 to slide along the inner wall of the linear slot under the push of the limiting baffle 2015. At this time, through the friction between the anti-slip rubber pad and the inner wall of the linear slot, the support plate 204 and the guide pressure plate 205 can slowly slide out along the inner wall of the linear slot until the limiting baffle 2015 contacts the inner wall of one end of the tool holder 5, so that the support plate 204 can slide out automatically.
[0062] Afterwards, the movable pusher 203 is released and the support plate 204 is pulled out. At this time, the blade 6 moves synchronously under the drive of the support plate 204 via bolts, nuts, and connecting plates. Then, the above operation is reversed. During this process, when the positioning block 208 is pushed by the support plate 204, it pushes the lifting slider 206 upward through the connecting push rod 207. At this time, the connecting push rod 207 slides along the outer wall of the guide slider through the guide groove. When the support plate 204 contacts the inner wall of one end of the blade holder 5, the second spring 2013 pushes the positioning block 208 into the interior of the support plate 204 by rebounding. In this way, multiple blades 6 can be individually locked and fixed, thereby achieving the purpose of convenient replacement of the blades 6, so as to further improve the efficiency of wire stripping.
[0063] The above description is merely a specific embodiment of this application, but the scope of protection of this application is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the technical scope disclosed in this application should be included within the scope of protection of this application. Therefore, the scope of protection of this application should be determined by the scope of the claims.
Claims
1. An auxiliary wire stripping mechanism for ignition head processing, comprising a base (1), wherein a receiving box (4) is slidably connected inside the base (1), a support seat (3) is installed at the top of the base (1), a guide rail (10) is fixedly connected to one end of the support seat (3), the guide rail (10) is located above the receiving box (4), and two tool holders (5) are symmetrically slidably sleeved on the outer wall of the guide rail (10), wherein multiple blades (6) are equidistantly arranged laterally at the ends of the two tool holders (5) that are close to each other, characterized in that, The tool holder (5) is provided with a replacement module for convenient replacement of the blade (6); The replacement module includes: multiple support plates (204) that are equidistantly slidably connected inside the tool holder (5); two guide plates (205) are symmetrically fixedly connected to the outer walls of the multiple support plates (204); the multiple support plates (204) are respectively located above the multiple blades (6); a linear slot is provided at the junction of the tool holder (5) with the support plates (204) and the guide plates (205) for sliding; a connecting plate is fixedly connected to the bottom end of the multiple support plates (204); the connecting plate is located on one side of the blade (6); the blade (6) is fixedly connected to the connecting plate by bolts and nuts.
2. The auxiliary wire stripping mechanism for ignition head processing according to claim 1, characterized in that, The replacement module also includes: a locking component disposed on the tool holder (5); The engaging assembly includes: multiple connecting push rods (207) that are laterally and equidistantly slidably connected inside the tool holder (5), the multiple connecting push rods (207) being located above multiple support plates (204) respectively, the bottom ends of the multiple connecting push rods (207) being fixedly connected to positioning blocks (208), one end of the outer wall of the positioning block (208) being inclined, the positioning block (208) penetrating into the interior of the support plate (204), and the top ends of the multiple connecting push rods (207) being fixedly connected to lifting sliders (206), one end of the outer wall of the lifting sliders (206) being inclined; The connecting push rod (207) is provided with a first reset component that drives the positioning block (208) to reset; The tool holder (5) is provided with a lifting component for pushing the lifting slider (206) to rise; The tool holder (5) is provided with a locking component for pressing and locking the lifting slider (206); The guide plate (205) is provided with a pushing component for pushing the guide plate (205) to move.
3. The auxiliary wire stripping mechanism for ignition head processing according to claim 2, characterized in that, The first reset component is a second spring (2013) sleeved on the outer wall of the connecting push rod (207). One end of the second spring (2013) is in contact with the inner wall of the tool holder (5), and the other end of the second spring (2013) is in contact with the outer wall of the positioning block (208).
4. The auxiliary wire stripping mechanism for ignition head processing according to claim 2, characterized in that, The lifting assembly includes: a lifting push plate (209) slidably connected inside the tool holder (5), the lifting push plate (209) being slidably sleeved on the outer wall of a plurality of connecting push rods (207), two fixed push blocks (2010) being symmetrically fixedly connected to the bottom end of the lifting push plate (209), and a movable push frame (203) being provided at the end of the tool holder (5) away from the support base (3), the movable push frame (203) being C-shaped. The blade holder (5) contacts the outer wall of the fixed push block (2010). The outer wall of the fixed push block (2010) at the junction with the movable push frame (203) is inclined. Two limiting sliders (2012) are symmetrically fixedly connected to the outer wall of the movable push frame (203). A limiting groove is provided at the junction of the blade holder (5) with the movable push frame (203) and the limiting sliders (2012) for sliding.
5. The auxiliary wire stripping mechanism for ignition head processing according to claim 2, characterized in that, The locking assembly includes: a movable pressure plate (201) slidably connected inside the tool holder (5), the movable pressure plate (201) contacting the outer wall of the lifting slider (206), the movable pressure plate (201) and the outer wall of the lifting slider (206) fitting together, a knurled bolt (202) provided at one end of the tool holder (5) away from the support base (3), the knurled bolt (202) penetrating the tool holder (5) and contacting the outer wall of the movable pressure plate (201), the tool holder (5) and the knurled bolt (202) being threadedly connected.
6. The auxiliary wire stripping mechanism for ignition head processing according to claim 2, characterized in that, The pushing component includes: a limiting slide rod (2014) disposed at one end of the guide plate (205), the limiting slide rod (2014) being in contact with the outer wall of the guide plate (205), and a limiting baffle (2015) being fixedly connected to the end of the limiting slide rod (2014) away from the guide plate (205), and both the limiting slide rod (2014) and the limiting baffle (2015) being slidably connected to the tool holder (5); The limiting baffle (2015) is provided with a second reset component.
7. The auxiliary wire stripping mechanism for ignition head processing according to claim 6, characterized in that, The second reset component is a first spring (2011) disposed at the end of the limiting baffle (2015) away from the limiting slide bar (2014). One end of the first spring (2011) is in contact with the outer wall of the limiting baffle (2015), and the other end of the first spring (2011) is in contact with the inner wall of the tool holder (5).
8. The auxiliary wire stripping mechanism for ignition head processing according to claim 1, characterized in that, A motor (7) is installed at the top of the support base (3). A bidirectional lead screw (9) is fixedly connected to the drive end of the motor (7). The bidirectional lead screw (9) is located inside the support base (3). The bidirectional lead screw (9) is rotatably connected to the support base (3) through an end shaft. Two movable frames (8) are symmetrically sleeved on the outer wall of the bidirectional lead screw (9). Both movable frames (8) are threadedly connected to the bidirectional lead screw (9). Both movable frames (8) are slidably connected to the support base (3). The two movable frames (8) are C-shaped. The two movable frames (8) are fixedly connected to two tool holders (5) respectively. The guide rail (10) is located inside the two movable frames (8).