Electric sealing door structure of refrigerated centrifuge
Through the design of the double-sided sealing open door structure and side-sliding components, the problem of lax sealing of the refrigeration centrifuge chamber door is solved, effective insulation and prevent condensation water, extend the equipment life, and improve the sealing effect.
Patent Information
- Application Number
- CN202411294475.6
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2024-09-14
- Publication Date
- 2024-12-10
AI Technical Summary
The sealing of the refrigeration centrifuge chamber door causes external hot air to penetrate, causing condensation water to generate, contaminate samples and damage the equipment, and the rubber parts of the one-way side-pull sealing door are easily damaged, affecting long-term sealing.
Adopt a double-sided sealed door open structure, including an inner push frame, push frame, side-sliding assembly, sealing gasket and guide wheel axle. The side-sliding assembly drives the push frame and sealing door to achieve lateral displacement, and uses sealing gasket and slot to provide reverse The directional force ensures that the sealing door is fit and prevents condensation water from being generated.
Effectively prevent the generation of condensate caused by temperature differences between the inside and outside, improve the sealing effect, extend the equipment life, reduce maintenance costs, and ensure the accuracy of experimental results and the long-term use of the equipment.
Smart Images
Figure CN119102471A_ABST
Abstract
Description
Technical Field
[0001] The invention belongs to the technical field of refrigerated centrifuge sealing, and in particular relates to an electric sealing door structure of a refrigerated centrifuge. Background Art
[0002] Refrigerated centrifuges play a vital role in modern scientific research, medical treatment, biopharmaceuticals and many other fields. Refrigerated centrifuges generate strong centrifugal force through high-speed rotation to separate substances of different densities. They are widely used in biochemistry, medical health, food safety and other industries to separate biological samples such as cells, viruses, proteins, nucleic acids and various chemical substances.
[0003] However, the hatch on the door of the refrigerated centrifuge currently has the problem of poor sealing, which has brought many problems to practical applications. On the one hand, when the refrigerated centrifuge is in operation, its interior needs to maintain an extremely low temperature, usually dozens of degrees below zero or even lower, to ensure the stability and activity of biological samples or chemicals. The temperature of the external environment is relatively high. When the hatch is not sealed tightly, the hot air from the outside will continue to penetrate into the refrigerated centrifuge. Due to the huge temperature difference between the inside and the outside, the water vapor in the hot air will quickly condense when it contacts the low-temperature surface, resulting in the generation of a large amount of condensed water.
[0004] The large amount of condensed water generated will bring a series of serious consequences. First, condensed water will accumulate in various parts inside the centrifuge, which may contaminate the samples being separated and affect the accuracy and reliability of the experimental results; secondly, condensed water may also damage the internal components of the refrigerated centrifuge. Electronic components and motors that are in a humid environment for a long time are prone to short circuits, corrosion and other faults, which reduce the service life of the centrifuge and increase the maintenance cost of the equipment. In order to solve the above problems, the existing technology uses a one-way electrically driven side-pull sealing door to seal the hatch on the refrigerated centrifuge door. Since the rubber parts on the sealing door need to be close to the inner wall of the hatch frame to achieve sealing, this repeated opening and closing action causes the rubber parts to rub against the inner wall of the hatch frame repeatedly, which is easy to damage and is not conducive to long-term internal sealing. Summary of the invention
[0005] In view of this, the present invention provides an electric sealing door structure of a refrigerated centrifuge, which can solve the problem that the rubber parts on the one-way side-pull sealing door are easily damaged and are not conducive to long-term internal sealing.
[0006] The present invention is achieved in that:
[0007] The present invention provides an electric sealed door structure of a refrigerated centrifuge, which includes a double-sided sealed door opening, a push outer frame and a side sliding component. The double-sided sealed door opening includes an inner push frame, and sliding blocks are arranged on the left and right sides of the inner push frame. Slide grooves are arranged on the inner walls on the left and right sides of the push outer frame. The inner push frame is slidably connected to the left and right sides of the push outer frame. The double-sided sealed door opening also includes sealed doors on upper and lower sides. Guide grooves are arranged on the side plates on the left and right sides of the sealed door. Guide wheel shafts are arranged on the inner walls on the left and right sides of the push outer frame. The guide wheel shafts are slidably matched with the guide grooves. The invention is suitable for realizing lifting of the sealing door to seal the window of the refrigerated centrifuge on both sides, the guide groove comprises an upper guide groove and a lower guide groove, the guide groove is an oblique slide groove adapted to the guide wheel shaft and a clamping groove for stopping the guide wheel shaft is arranged at the end, the clamping groove is semicircular and tangent to the oblique slide groove, a sealing gasket is arranged on the sealing door, an extrusion kit is arranged between the pushing outer frame and the inner pushing frame, guide slide seats are fixedly connected to the outer walls on the left and right sides of the pushing outer frame, and the side sliding assembly comprises a front push bar, a rear push bar, a driving screw and guide slide bars on the left and right sides.
[0008] The technical effect of an electric sealed door structure of a refrigerated centrifuge provided by the present invention is as follows: a side sliding component is set to drive the outer frame and the double-sided sealed doors to achieve lateral displacement. When the double-sided sealed doors reach the position, the outer frame is pushed to continue to displace under the action of the extrusion kit. During the displacement process, the slide grooves on the inner walls of the two sides of the outer frame are pushed to slide forward along the sliders on the left and right sides of the inner push frame, and the guide grooves on the side plates on both sides of the sealed door are affected by the guide wheel shafts on the inner walls of the two sides of the outer frame, driving the sealed doors on both sides to be lifted to both sides. During the process, the guide wheel shafts slide along the oblique slide grooves until they reach the card slot position and stop. At this time, since the sealing gasket is pressed against the warehouse opening frames on both sides to provide a reverse force, it can cooperate with the card slot to effectively prevent the sealed doors on both sides from retreating inward after the screw motor is powered off. Therefore, the sealing gasket is used to achieve a sealing fit effect, and the closing and sealing of the warehouse doors on both sides are realized, which is helpful for internal heat preservation and preventing the generation of condensed water due to the temperature difference between the inside and the outside.
[0009] On the basis of the above technical solution, the electric sealing door structure of a refrigerated centrifuge of the present invention can also be improved as follows:
[0010] Wherein, the extrusion kit includes a pressure rod and a pressure spring, one end of the pressure rod is fixedly connected to the inner push frame by a thread, and the push outer frame is provided with an adaptive movable groove corresponding to the position of the pressure rod.
[0011] The beneficial effect of adopting the above-mentioned improvement scheme is: by setting a pressure rod to cooperate with the compression spring and the movable groove, when the inner push frame reaches the front push bar position, the side sliding assembly can continue to drive the outer frame to push the compression spring for displacement. At the same time, the guide wheel shaft cooperates with the guide groove to realize the lifting and sealing of the sealing door to both sides.
[0012] Furthermore, the other end of the pressure rod is movably connected to the movable groove.
[0013] Furthermore, one end of the compression spring is sleeved on the outside of the pressure rod, and the other end contacts the bottom wall of the sliding groove, so as to realize the forward displacement of the outer frame so that the compression spring is compressed and cooperates with the guide wheel shafts on both sides to drive the sealing door to be lifted up to both sides along the guide groove on the side panel for sealing.
[0014] Furthermore, the driving screw includes a screw motor, a screw shaft and a screw nut.
[0015] The beneficial effect of adopting the above-mentioned improvement scheme is: the screw motor is used to drive the screw shaft to rotate, and the screw nut is installed on the pushing outer frame to cooperate with the rotation of the screw shaft to achieve linear displacement.
[0016] Furthermore, a mounting groove for the screw motor is provided on the rear push bar, and the screw motor is fixedly connected to the mounting groove by bolts.
[0017] Furthermore, a nut mounting hole for the lead screw nut is opened on the pushing outer frame, and the lead screw nut is fixedly connected to the nut mounting hole by bolts.
[0018] Furthermore, one end of the screw shaft is fixedly connected to the output end of the screw motor, and a circular through hole is opened on the inner push frame at one side corresponding to the screw shaft.
[0019] Furthermore, the diameter of the circular through hole is larger than the cross-sectional diameter of the screw shaft.
[0020] The beneficial effect of adopting the above-mentioned improvement scheme is: by setting a circular through hole, when opening the double-sided sealed door, when the screw shaft drives the outer frame to retract, the end of the screw shaft can pass through the circular through hole without affecting its rotation.
[0021] Furthermore, the two ends of the guide slide rod are fixedly connected to the front push bar and the rear push bar respectively by bolts, and a through hole is opened on the guide slide seat. The guide slide seat slides with the guide slide rod through the through hole to play a guiding role when the outer frame is pushed to move.
[0022] The beneficial effect of adopting the above-mentioned improvement scheme is: by setting a guide slide rod, when the screw shaft drives the outer frame to move, it cooperates with the guide slide seats on both sides of the outer frame to play a sliding guide role, making the displacement activity more stable and ensuring the accuracy of linear displacement.
[0023] Compared with the prior art, the electric sealed door structure of a refrigerated centrifuge provided by the present invention has the following beneficial effects: by arranging a side sliding assembly to drive the outer frame and the double-sided sealed door opening to achieve lateral displacement, when the double-sided sealed door opening reaches the position, under the action of the extrusion kit, the outer frame is pushed to continue to displace, during the displacement process, the slide grooves on the inner walls on both sides of the outer frame are pushed to slide forward along the sliders on the left and right sides of the inner push frame, and the guide grooves on the side plates on both sides of the sealed door are affected by the guide wheel shafts on the inner walls on both sides of the outer frame, driving the sealed doors on both sides to be lifted up to both sides, and sealed with the two sides of the port of the refrigerated centrifuge through sealing gaskets to achieve closing and sealing effects, which is helpful for internal heat preservation and preventing the generation of condensed water due to the temperature difference between the inside and the outside; by arranging a pressure rod to cooperate with the compression spring and the movable groove to achieve that when the inner push frame reaches the front push bar position, the side sliding assembly can continue to drive the outer frame to push against the compression spring for displacement, and at the same time, the sealing door is lifted up and sealed to both sides through the guide wheel shaft and the guide groove. BRIEF DESCRIPTION OF THE DRAWINGS
[0024] In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the accompanying drawings required for use in the description of the embodiments of the present invention will be briefly introduced below. Obviously, the accompanying drawings in the following description are only some embodiments of the present invention. For ordinary technicians in this field, other accompanying drawings can be obtained based on these accompanying drawings without paying creative labor.
[0025] Figure 1 It is a schematic diagram of an electric sealing door structure of a refrigerated centrifuge;
[0026] Figure 2 It is a schematic diagram of an inner push frame and a guide groove of an electric sealed door structure of a refrigerated centrifuge;
[0027] Figure 3 It is a top schematic diagram of an electric sealing door structure of a refrigerated centrifuge;
[0028] Figure 4 It is a schematic diagram of an upper guide groove and a lower guide groove of a second embodiment of an electric sealing door structure of a refrigerated centrifuge;
[0029] Figure 5 A schematic diagram of an upper guide groove and a lower guide groove of a third embodiment of an electric sealing door structure of a refrigerated centrifuge;
[0030] Figure 6 It is a schematic diagram of the position of an electric sealing door structure of a refrigerated centrifuge at the bottom end of the centrifuge compartment door;
[0031] Figure 7 It is a schematic diagram of the position of an electric sealing door structure of a refrigerated centrifuge at the top of the centrifuge compartment door;
[0032] In the accompanying drawings, the components represented by the reference numerals are listed as follows:
[0033] 10. Double-sided sealed door opening; 11. Push outer frame; 12. Side sliding assembly; 13. Inner push frame; 14. Sealed door; 15. Guide wheel shaft; 16. Guide groove; 17. Sealing gasket; 18. Pressure rod; 19. Compression spring; 20. Guide slide; 21. Front push bar; 22. Rear push bar; 23. Driving screw; 24. Guide slide. DETAILED DESCRIPTION
[0034] In order to make the purpose, technical solution and advantages of the embodiments of the present invention more clear, the technical solution in the embodiments of the present invention will be clearly and completely described below in conjunction with the accompanying drawings in the embodiments of the present invention.
[0035] Embodiment 1:
[0036] like Figure 1 , 2 , 3, 6, and 7 are shown as a first embodiment of an electric sealed door structure of a refrigerated centrifuge provided by the present invention. In this embodiment, it includes a double-sided sealed door opening 10, a pushing outer frame 11, and a side sliding assembly 12. The double-sided sealed door opening 10 includes an inner push frame 13, and sliders are arranged on the left and right sides of the inner push frame 13. Slide grooves are arranged on the inner walls of the left and right sides of the pushing outer frame 11. The inner push frame 13 is slidably connected to the left and right sides of the pushing outer frame 11. The double-sided sealed door opening 10 also includes sealed doors 14 on the upper and lower sides. Guide grooves 16 are arranged on the side panels on the left and right sides of the sealing door 14. Guide wheel shafts 15 are arranged on the inner walls of the left and right sides of the pushing outer frame 11. The sliding cooperation between the guide wheel shaft 15 and the guide groove 16 is used to lift the sealing door 14 to seal the window of the refrigerated centrifuge on both sides. The guide groove 16 includes an upper guide groove and a lower guide groove. The guide groove 16 is an oblique slide groove adapted to the guide wheel shaft 15 and a clamping groove for parking the guide wheel shaft 15 is provided at the end. The clamping groove is semicircular and tangent to the oblique slide groove. A sealing gasket 17 is provided on the sealing door 14, and an extrusion kit is provided between the push outer frame 11 and the inner push frame 13. The outer walls on the left and right sides of the push outer frame 11 are fixedly connected with guide slides 20. The side sliding assembly 12 includes a front push bar 21, a rear push bar 22, a driving screw 23 and guide slides 24 on the left and right sides.
[0037] When in use, the screw motor drives the screw shaft to rotate, and the screw nuts on the outer frame 11 cooperate with the guide slides 20 on both sides to drive the outer frame 11 to move and close. At this time, the inner push frame 13 and the sealing doors 14 on both sides are in a state of simultaneous displacement. When one end of the inner push frame 13 contacts the front push bar 21, the screw shaft keeps rotating. Since the inner push frame 13 and the outer push frame 11 are in contact through the extrusion kit, and there is still a displaceable gap between the outer frame 11 and the front push bar 21 at this time, when the screw shaft keeps rotating, the outer frame 11 is pushed to resist the compression spring 19 through the bottom wall of the sliding groove. The compression spring 19 is compressed by force, and at the same time, the guide wheel shaft 15 moves inside the guide groove 16, forcing the sealing doors 14 on both sides to be pushed outward, so as to achieve the sealing of the sealing gasket 17 and the two sides of the refrigerated centrifuge compartment opening, thereby achieving the effect of closing and sealing the compartment opening.
[0038] Among them, in the above technical solution, the extrusion kit includes a pressure rod 18 and a pressure spring 19, one end of the pressure rod 18 is fixedly connected to the inner push frame 13 by a thread, and the outer frame 11 is pushed to open an adaptive movable groove corresponding to the position of the pressure rod 18.
[0039] Furthermore, in the above technical solution, the other end of the pressure rod 18 is movably connected to the movable groove.
[0040] Furthermore, in the above technical solution, one end of the compression spring 19 is sleeved on the outside of the pressure rod 18, and the other end is in contact with the bottom wall of the sliding groove, so as to push the outer frame 11 forward so that the compression spring 19 is compressed and cooperates with the guide wheel shafts 15 on both sides to drive the sealing door 14 to be lifted up to both sides along the guide grooves 16 on the side panels for sealing.
[0041] Furthermore, in the above technical solution, the driving screw 23 includes a screw motor, a screw shaft and a screw nut.
[0042] Furthermore, in the above technical solution, a mounting groove for the screw motor is provided on the rear push bar 22, and the screw motor is fixedly connected to the mounting groove by bolts.
[0043] Furthermore, in the above technical solution, a nut mounting hole for a lead screw nut is provided on the push outer frame 11, and the lead screw nut is fixedly connected to the nut mounting hole by bolts.
[0044] Furthermore, in the above technical solution, one end of the screw shaft is fixedly connected to the output end of the screw motor, and a circular through hole is opened on the inner push frame 13 corresponding to one side of the screw shaft.
[0045] Furthermore, in the above technical solution, the diameter of the circular through hole is larger than the cross-sectional diameter of the screw shaft.
[0046] Furthermore, in the above technical solution, the two ends of the guide slide rod 24 are fixedly connected to the front push bar 21 and the rear push bar 22 respectively by bolts, and a through hole is opened on the guide slide seat 20. The guide slide seat 20 slides with the guide slide rod 24 through the through hole, so as to play a guiding role when pushing the outer frame 11 to move.
[0047] Furthermore, in the above technical scheme, a group of pressure sensors are respectively arranged on the front push bar 21 and the rear push bar 22. The pressure sensor on the front push bar 21 is arranged close to the side of the push outer frame 11, and is used to sense whether the two sides of the push outer frame 11 are in contact with the front push bar 21 when the sealing door 14 is closed. The pressure sensor on the rear push bar 22 is used to sense whether the screw motor drives the push outer frame 11 to retreat and is in contact with the rear push bar 22 when the sealing door 14 is opened, so as to cooperate with the controller to realize the control of the screw motor, wherein the pressure rod sensor and the screw motor are electrically connected to the controller respectively.
[0048] Specifically, the principle of the present invention is: when in use, the screw motor drives the screw shaft to rotate, and the screw nuts on the outer frame 11 cooperate with the guide slides 20 on both sides to drive the outer frame 11 to move and close. At this time, the inner push frame 13 and the sealing doors 14 on both sides are in a state of simultaneous displacement. When one end of the inner push frame 13 contacts the front push bar 21, the screw shaft keeps rotating. Since the inner push frame 13 and the outer push frame 11 are in contact through the extrusion kit, and there is still a displaceable gap between the outer frame 11 and the front push bar 21 at this time, when the screw shaft keeps rotating, the outer frame 11 is pushed through the bottom wall of the sliding groove to resist the compression spring 19, and the compression spring 19 is compressed by force. At the same time, the guide wheel shaft 15 moves inside the guide groove 16, forcing the sealing doors 14 on both sides to be pushed outward, so as to achieve the sealing of the sealing gasket 17 and the two sides of the refrigerated centrifuge compartment opening, thereby achieving the effect of closing and sealing the compartment opening.
[0049] Embodiment 2:
[0050] like Figure 4As shown, it is a second embodiment of the electric sealing door structure of a refrigerated centrifuge provided by the present invention: wherein the oblique sliding groove portion of the guide groove 16 is provided with an inflection point, and taking the operation of the guide wheel shaft 15 in closing the sealing door 14 as an example, the axis point of the guide wheel shaft 15 at the starting position inside the guide groove 16 is used to construct point A, and when the sealing doors 14 on both sides are completely sealed with the inner walls on both sides of the port through the sealing gasket 17, the axis point of the guide wheel shaft 15 at the end position in contact with the end slot inside the guide groove 16 is used to construct point B, wherein the connection distance between point A and the inflection point is L (the distance range of the L straight line is 10 to 30 mm), and the connection distance between point B and the inflection point is M (the distance range of the M straight line is 3 to 8 mm), (the diameter size of the guide wheel shaft 15 is 10 to 14 mm); wherein the L straight line and the horizontal movement direction straight line of the guide wheel shaft 15 form an angle α, and the M straight line and the horizontal movement straight line of the guide wheel shaft 15 form an angle β, and the angle value of the angle α is greater than the angle value of the angle β;
[0051] Specifically, when the straight line distance of L is 16 mm, the straight line distance of M is 5 mm, the angle value of the constructed angle α is 10 degrees, and the angle value of the angle β is 5 degrees; this embodiment is suitable for the case where the thickness of the insulation layer on the inner wall of the warehouse opening on both sides of the warehouse door is the same, so the distance between the straight line L and M on the upper guide groove and the lower guide groove is exactly the same.
[0052] Embodiment three:
[0053] like Figure 5 As shown, in order to consider the economic efficiency of the device, in order to keep the interior of the existing refrigerated centrifuge constant temperature, a heat preservation layer structure (which can be a filling layer or a heat preservation plate) is usually only provided on the side of the lower layer of the door that contacts the centrifugal chamber of the centrifuge, which results in the sealed door 14 on the bottom side being stored further inside the inner push frame 13 than the sealed door 14 on the upper side when the chamber is opened. Therefore, this embodiment further improves the embodiment of the present invention in view of this usage, so that the linear distance L on the lower guide groove is greater than the linear distance L on the upper guide groove, and the angle α of the lower guide groove is greater than the angle α of the upper guide groove, wherein the angle β of the upper guide groove is the same as that of the lower guide groove;
[0054] Specifically, when the straight-line distance L of the upper guide groove is 16 mm, the straight-line distance M is 5 mm, the angle value of the constructed angle α is 10 degrees, and the angle value of the angle β is 5 degrees, the straight-line distance L of the lower guide groove is 17.5 mm, the straight-line distance M is 5 mm, the angle value of the constructed angle α is 27 degrees, and the angle value of the angle β is 5 degrees.
Claims
1. An electric sealing door structure of a refrigerated centrifuge, characterized in that: The double-sided sealed door opening (10) comprises a double-sided sealed door opening (10), a push outer frame (11) and a side sliding assembly (12). The double-sided sealed door opening (10) comprises an inner push frame (13). Slide blocks are arranged on the left and right sides of the inner push frame (13). Slide grooves are arranged on the inner walls on the left and right sides of the push outer frame (11). The inner push frame (13) is slidably connected to the left and right sides of the push outer frame (11). The double-sided sealed door opening (10) also comprises sealing doors (14) on the upper and lower sides. Guide grooves (16) are arranged on the side plates on the left and right sides of the sealing door (14). Guide wheel shafts (15) are arranged on the inner walls on the left and right sides of the push outer frame (11). The guide wheel shafts (15) and the guide grooves (16) are slidably matched to realize the sealing door (14) The window of the refrigerated centrifuge is lifted up to seal on both sides. The guide groove (16) includes an upper guide groove and a lower guide groove. The guide groove (16) is an oblique slide groove adapted to the guide wheel shaft (15) and a clamping groove for parking the guide wheel shaft (15) is arranged at the end. The clamping groove is semicircular and tangent to the oblique slide groove. A sealing gasket (17) is arranged on the sealing door (14). An extrusion kit is arranged between the pushing outer frame (11) and the inner pushing frame (13). The outer walls on the left and right sides of the pushing outer frame (11) are fixedly connected with guide slide seats (20). The side sliding assembly (12) includes a front push rod (21), a rear push rod (22), a driving screw (23) and guide slide rods (24) on the left and right sides.
2. The electric sealing door structure of a refrigerated centrifuge according to claim 1, characterized in that: The extrusion kit comprises a pressure rod (18) and a pressure spring (19); one end of the pressure rod (18) is fixedly connected to the inner push frame (13) by means of a thread; and the outer push frame (11) is provided with an adaptive movable groove corresponding to the position of the pressure rod (18).
3. The electric sealing door structure of a refrigerated centrifuge according to claim 2, characterized in that: The other end of the pressure rod (18) is movably connected to the movable groove.
4. The electric sealing door structure of a refrigerated centrifuge according to claim 3, characterized in that: One end of the compression spring (19) is sleeved on the outside of the compression rod (18), and the other end is in contact with the bottom wall of the sliding groove, so as to realize the forward displacement of the pushing outer frame (11) so that the compression spring (19) is compressed and cooperates with the guide wheel shafts (15) on both sides to drive the sealing door (14) to be lifted up to both sides along the guide grooves (16) on the side plates for sealing.
5. The electric sealing door structure of a refrigerated centrifuge according to claim 4, characterized in that: The driving screw (23) comprises a screw motor, a screw shaft and a screw nut.
6. The electric sealing door structure of a refrigerated centrifuge according to claim 5, characterized in that: The rear push bar (22) is provided with a mounting groove for the lead screw motor, and the lead screw motor is fixedly connected to the mounting groove by bolts.
7. The electric sealing door structure of a refrigerated centrifuge according to claim 6, characterized in that: The pushing outer frame (11) is provided with a nut mounting hole for the lead screw nut, and the lead screw nut is fixedly connected to the nut mounting hole by means of bolts.
8. The electric sealing door structure of a refrigerated centrifuge according to claim 7, characterized in that: One end of the lead screw shaft is fixedly connected to the output end of the lead screw motor, and a circular through hole is provided on the inner push frame (13) corresponding to one side of the lead screw shaft.
9. The electric sealing door structure of a refrigerated centrifuge according to claim 8, characterized in that: The diameter of the circular through hole is larger than the cross-sectional diameter of the screw shaft.
10. The electric sealing door structure of a refrigerated centrifuge according to claim 9, characterized in that: The two ends of the guide slide bar (24) are fixedly connected to the front push bar (21) and the rear push bar (22) respectively by bolts, and a through hole is opened on the guide slide seat (20). The guide slide seat (20) slides with the guide slide bar (24) through the through hole to play a guiding role when the outer frame (11) is pushed to move.