An oil injector using a gear connecting rod mechanism to generate oil injection power

Abstract

The utility model relates to the technical field of oilers, and in particular to an oiler that uses a gear-connecting rod mechanism to generate oil injection power; it comprises an oil filling tank, an oil filling port arranged on the oil filling tank, a piston slidably connected inside the oil filling tank for pushing grease to be extruded from the oil filling port, and a power module installed on the oil filling tank for providing power to the piston, the power module comprises a fixed shell fixedly installed on the oil filling tank, a power motor installed on the fixed shell, a gear group that is transmission-connected to the power motor, a rack group that is slidably connected to the fixed shell and meshes with the gear group, and a cross connecting rod that is docked between the fixed shell and the piston and driven by the rack group, wherein the cross connecting rod generates a push-pull force driven by the rack group to drive the piston to slide along the inside of the oil filling tank; no complex air path system and control elements are required, which reduces the complexity and potential failure points of the system.

Description

Technical Field

[0001] The utility model relates to the technical field of oil injectors, in particular to an oil injector which adopts a gear connecting rod mechanism to generate oil injection power. Background Art

[0002] An automatic oiler is a device that can automatically provide lubricating grease to mechanical equipment. It can improve the accuracy and timeliness of lubrication, ensure that the equipment is continuously and properly lubricated, help extend the service life of the equipment, reduce wear and failure, and save manpower, eliminating the need for frequent manual lubrication operations. Automatic oilers are usually used in various industrial fields, such as manufacturing, mining, transportation, etc., to ensure the normal operation and performance of mechanical equipment.

[0003] The existing traditional oiler mainly includes an oil filling tank, a piston arranged inside the oil filling tank, and an air source module that applies air pressure to one end of the oil filling tank to push the piston to the other end and squeeze out the grease stored at the other end from the oil filling port of the oil filling tank. However, during use, the inventor found that the use of the air source module requires attention to the air tightness of the oiler. In terms of structural design, if a better sealing setting is not performed, it is easy to cause leakage and the like. In addition, the oiler has a long service life, and its air source part needs to maintain sealing for a long time. It is easy to cause leakage due to aging or some bumps and the like, thereby causing the air source module to be unable to supply air normally to push its piston to operate, resulting in the inability to achieve the purpose of normal extrusion of grease. In this regard, it is necessary to propose an improved technical solution to solve the above problems. Utility Model Content

[0004] The utility model aims to overcome the above-mentioned shortcomings and provide a technical solution that can solve the above-mentioned problems.

[0005] An oiler that uses a gear-connecting rod mechanism to generate oil injection power, comprising an oil filling tank, an oil filling port arranged on the oil filling tank, a piston slidably connected to the inside of the oil filling tank for pushing grease to be squeezed out of the oil filling port, and a power module installed on the oil filling tank for providing power to the piston, the power module comprising a fixed shell fixedly installed on the oil filling tank, a power motor installed on the fixed shell, a gear set that is transmission-connected to the power motor, a rack set that is slidably connected to the fixed shell and meshes with the gear set, and a cross connecting rod that is connected between the fixed shell and the piston and driven by the rack set, wherein the cross connecting rod generates a push-pull force driven by the rack set to drive the piston to slide along the inside of the oil filling tank.

[0006] Preferably, both ends of the cross-linking rod respectively have a hinged end and a free end, both ends of the cross-linking rod are respectively hinged to the fixed housing and the piston through the hinged ends, and one end of the cross-linking rod is transmission-connected to the rack assembly through the free end.

[0007] Preferably, two groups of cross-linking rods are provided, and the two groups of cross-linking rods are symmetrical to the central axis of the piston. The rack group includes a first rack and a second rack. The first rack and the second rack are both slidably connected to the fixed shell, and the first rack and the second rack are driven by the gear group to slide in relative opposite directions.

[0008] Preferably, the gear set includes a power gear dynamically connected to a power motor, a reduction gear rotatably connected to a fixed housing and meshing with the power gear, and an output gear rotatably connected to the fixed housing and meshing with the reduction gear, the first rack and the second rack are respectively arranged in parallel on both sides of the output gear, and the first rack and the second rack are respectively meshed with the output gear.

[0009] Preferably, the output gear comprises an upper gear meshed with the reduction gear and a lower gear coaxially connected to the upper gear, and the first rack and the second rack are respectively meshed with the lower gear.

[0010] Preferably, the gear set also includes a fixed base installed inside the fixed shell, the drive motor is installed on the fixed base, the reduction gear, the upper gear and the lower gear are all rotatably connected to the fixed base, wherein the reduction gear and the upper gear are both rotatably connected to the upper end of the fixed base, and the lower gear is rotatably connected to the lower end of the fixed base.

[0011] Preferably, a rotating shaft is provided at the lower end of the upper gear, and the upper gear is rotatably connected to the upper end of the fixed seat through the rotating shaft, and a square block is provided at the lower end of the rotating shaft, and a square sleeve matching the square block is provided at the upper end of the lower gear, and the upper gear and the lower gear are coaxially docked by docking the square block and the square sleeve.

[0012] Preferably, the fixed shell includes an upper shell and a lower shell that are butt-jointed with each other, and a flat window corresponding to the cross-linking rod is arranged on the upper shell, the cross-linking rod extends into the interior of the fixed shell along the flat window, and the hinged end of the cross-linking rod is hinged inside the flat window, and a sliding gap corresponding to the flat window and the gear set is formed between the upper shell and the lower shell after being fixedly covered, and the first rack and the second rack both have a sliding portion that slides in the sliding gap and a rack portion formed on one side of the sliding portion and meshed with the gear set, and the sliding portion is hinged to the free end of the cross-linking rod.

[0013] Preferably, the lower end of the oil filling tank is provided with an opening, the fixed housing is threadedly connected to the opening at the lower end of the oil filling tank, and a limit block is provided at the upper end of the fixed housing, the limit block being used to limit the sliding stroke of the piston.

[0014] Preferably, a circuit module electrically connected to the power motor is arranged inside the fixed housing, and the circuit module (26) is also electrically connected to a time adjustment knob, and the time adjustment knob is exposed outside the fixed housing.

[0015] Compared with the prior art, the beneficial effects of the utility model are:

[0016] A transmission mechanism for driving the movement of the cross-link is formed by the cooperation of a gear set and a rack set. The rotational power generated by the power motor is used to generate linear power through the meshing of the gear set and the rack set. When the power motor rotates forward and reverse, the rack set will also rotate back and forth, thereby pushing the cross-link connected between the fixed housing and the piston to move. The cross-link generates a telescopic movement through its own linkage relationship, thereby driving the piston to move back and forth along the inside of the oil filling tank.

[0017] The cross-link power module is relatively simple and does not require complex gas circuit systems and control components. This reduces the complexity of the system and potential failure points. For example, in some simple industrial equipment, simple mechanical structures are easier to maintain and repair; and because the structure is relatively simple, the manufacturing and assembly costs are usually low. Unlike air pump systems, which may require high-precision manufacturing and expensive materials.

[0018] The cross-link power module can directly convert power into piston movement, and the loss in the energy transfer process is relatively small. In contrast, the air pump may have more energy loss in the process of compressing and transmitting gas; and the reliability of the mechanical structure is often higher, and it is not easily affected by problems such as air pressure fluctuations and gas leakage. For example, in harsh working environments, the cross-link power module can work more stably. For some special working conditions, such as high temperature and high humidity, the mechanical structure may have better adaptability, while the air pump may be greatly affected by these factors.

[0019] Additional aspects and advantages of the present invention will be given in part in the following description, and in part will become apparent from the following description, or will be learned through the practice of the present invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] In order to more clearly illustrate the embodiments of the utility model or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the utility model. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative labor.

[0021] Figure 1 It is a structural schematic diagram of the utility model;

[0022] Figure 2 It is a schematic diagram of a cross-sectional structure of the utility model;

[0023] Figure 3It is another cross-sectional structural schematic diagram of the utility model;

[0024] Figure 4 This utility model Figure 3 The structural diagram at A in the middle;

[0025] Figure 5 It is a half-section structural schematic diagram of the power module of the utility model;

[0026] Figure 6 This is a schematic diagram of the structure of the power module of the utility model after removing the fixed housing;

[0027] Figure 7 It is a schematic diagram of the structure of the cross connecting rod and the rack group in the utility model;

[0028] Figure 8 It is a structural schematic diagram of the gear set and the power motor in the utility model;

[0029] Fig. 9 It is a structural schematic diagram of the output gear of the utility model.

[0030] The reference numerals and names in the figures are as follows:

[0031] Oil filling tank 10, oil filling port 11, piston 12, power module 20, fixed shell 21, upper shell 211, lower shell 212, flat window 213, sliding gap 214, limit block 215, power motor 22, gear set 23, power gear 231, reduction gear 232, output gear 233, upper gear 2331, lower gear 2332, rotating shaft 2333, square block 2334, square sleeve 2335, fixed seat 234, rack set 24, first rack 241, second rack 242, sliding part 243, rack part 244, cross connecting rod 25, first connecting rod 251, second connecting rod 252, time adjustment knob 27. DETAILED DESCRIPTION

[0032] The technical solutions in the embodiments of the present invention are described clearly and completely below. Obviously, the described embodiments are only a part of the embodiments of the present invention, not all of them. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0033] See also Figure 1-9In an embodiment of the utility model, an oiler that uses a gear-connecting rod mechanism to generate oil injection power is proposed, including an oil filling tank 10, an oil filling port 11 arranged on the oil filling tank 10, a piston 12 slidably connected to the inside of the oil filling tank 10 for pushing the grease to be squeezed out of the oil filling port 11, and a power module 20 installed on the oil filling tank 10 for providing power to the piston 12. The power module 20 includes a fixed shell 21 fixedly installed on the oil filling tank 10, a power motor 22 installed on the fixed shell 21, a gear set 23 that is transmission-connected to the power motor 22, a rack set 24 that is slidably connected to the fixed shell 21 and meshes with the gear set 23, and a cross-link 25 that is docked between the fixed shell 21 and the piston 12 and driven by the rack set 24, wherein the cross-link 25 generates a push-pull force driven by the rack set 24 to drive the piston 12 to slide along the inside of the oil filling tank 10.

[0034] In the above technical solution, a power module 20 with a cross connecting rod 25 is provided to provide power for the piston 12 to slide along the inside of the oil filling tank 10. The gear set 23 and the rack set 24 are used to form a transmission mechanism for driving the cross connecting rod 25 to move. The rotational power generated by the power motor 22 is used to generate linear power through the meshing of the gear set 23 and the rack set 24. When the power motor 22 is running forward and reverse, the rack set 24 will also run forward and reverse back and forth, thereby pushing the cross connecting rod 25 docked between the fixed shell 21 and the piston 12 to move. The cross connecting rod 25 generates a telescopic movement through its own linkage relationship, thereby driving the piston 12 to realize a back and forth movement along the inside of the oil filling tank 10.

[0035] The power module 20 of the cross link 25 is relatively simple in composition and does not require a complex gas circuit system and control components. This reduces the complexity of the system and potential failure points. For example, in some simple industrial equipment, a simple mechanical structure is easier to maintain and repair; and because the structure is relatively simple, the manufacturing and assembly costs are usually low. Unlike an air pump system, which may require high-precision manufacturing and expensive materials.

[0036] The power module 20 of the cross-link 25 can directly convert power into the movement of the piston 12, and the loss in the energy transfer process is relatively small. In contrast, the air pump may have more energy loss in the process of compressing and transmitting gas; and the reliability of the mechanical structure is often higher, and it is not easily affected by problems such as air pressure fluctuations and gas leakage. For example, in a harsh working environment, the power module 20 of the cross-link 25 can work more stably. For some special working conditions, such as high temperature, high humidity and other environments, the adaptability of the mechanical structure may be better, while the air pump may be greatly affected by these factors.

[0037] Further reading Figure 2-6 In the embodiment of the utility model, both ends of the cross link 25 have a hinged end and a free end respectively, and both ends of the cross link 25 are respectively hinged to the fixed housing 21 and the piston 12 through the hinged end, and one end of the cross link 25 is transmission-connected to the rack set 24 through the free end; that is, by hingedly connecting the hinged end, and then using the rack set 24 to drive the free end, the cross link 25 can produce a movement similar to telescopic movement, thereby driving the piston 12 to move; considering that the force between the cross link 25 and the piston 12 does not deviate, the embodiment of the utility model further connects the cross link 25 to the fixed housing 21 and the piston 12. There are two groups of connecting rods 25, and the two groups of cross connecting rods 25 are symmetrical to the central axis of the piston 12. The rack group 24 includes a first rack 241 and a second rack 242. The first rack 241 and the second rack 242 are both slidably connected to the fixed shell 21, and the first rack 241 and the second rack 242 are respectively driven by the gear group 23 to slide in relative opposite directions; in this way, the two groups of cross connecting rods 25 will be able to always apply force to the piston 12 along its sliding direction without deviation during the process of driving the piston 12 to move, thereby ensuring the stable operation of the piston 12.

[0038] Further reading Figure 2-8 In the embodiment of the utility model, in order to ensure that the two groups of cross-links 25 can run synchronously, a gear set 23 is provided, which includes a power gear 231 connected to the power motor 22, a reduction gear 232 connected to the fixed housing 21 and meshed with the power gear 231, and an output gear 233 connected to the fixed housing 21 and meshed with the reduction gear 232. The first rack 241 and the second rack 242 are respectively arranged on both sides of the output gear 233 in parallel, and the first rack 241 and the second rack 242 are respectively meshed with the output gear 233; that is, the opposite direction structure generated by the bonding of the two sides of the output gear 233 is used, so that the first rack 241 and the second rack 242 can move in opposite directions relative to each other. movement, thereby realizing synchronous operation of the two groups of cross-links 25; in addition, the output gear 233 includes an upper gear 2331 meshed with the reduction gear 232 and a lower gear 2332 coaxially connected to the upper gear 2331, and the first rack 241 and the second rack 242 are respectively meshed with the lower gear 2332, that is, the diameter of the upper reduction gear 232 is set to be larger than that of the output gear 233, which causes the reduction gear 232 to interfere with the rack set 24. Therefore, the output gear 233 is set to an upper gear 2331 and a lower gear 2332, so that the gear set 23 is divided into an upper and lower layer, thereby realizing a close fit between the gear set 23 and the rack set 24 in the longitudinal space, making the overall structure more compact and stable.

[0039] Further reading Figure 5 , Figure 6 , Figure 8 and Fig. 9 In the embodiment of the utility model, based on the structural assembly relationship between the gear set 23 and the fixed housing 21, the gear set 23 also includes a fixed seat 234 installed inside the fixed housing 21, the driving motor is installed on the fixed seat 234, the reduction gear 232, the upper gear 2331 and the lower gear 2332 are all rotatably connected to the fixed seat 234, wherein the reduction gear 232 and the upper gear 2331 are all rotatably connected to the upper end of the fixed seat 234, and the lower gear 2332 is rotatably connected to the lower end of the fixed seat 234; the upper gear 23 A rotating shaft 2333 is provided at the lower end of 31, and the upper gear 2331 is rotatably connected to the upper end of the fixed seat 234 through the rotating shaft 2333, and a square block 2334 is provided at the lower end of the rotating shaft 2333, and a square sleeve 2335 matching the square block 2334 is provided at the upper end of the lower gear 2332, and the upper gear 2331 and the lower gear 2332 are coaxially docked by docking the square block 2334 and the square sleeve 2335; the fixed seat 234 can be directly installed in the fixed shell 21, so as to facilitate the modular production of the structure.

[0040] Further reading Figure 4 , Figure 5 and Figure 7 In the embodiment of the utility model, the fixed shell 21 includes an upper shell 211 and a lower shell 212 that are connected to each other. A flat window 213 corresponding to the cross-link 25 is arranged on the upper shell 211. The cross-link 25 extends into the interior of the fixed shell 21 along the flat window 213, and the hinged end of the cross-link 25 is hinged inside the flat window 213. After the upper shell 211 and the lower shell 212 are fixedly covered, a sliding gap 214 corresponding to the flat window 213 and the gear set 23 is formed between the two. The first rack 241 and the second rack 242 both have a sliding portion 243 that slides in the sliding gap 214 and a rack portion 244 formed on one side of the sliding portion 243 and meshing with the gear set 23. The sliding portion 243 is hinged to the free end of the cross-link 25. The structure is simple to set up and can ensure the stable operation of the cross-link 25.

[0041] Further reading Figure 1-3 In the embodiment of the utility model, an opening is provided at the lower end of the oil filling tank 10, and the fixed shell 21 is threadedly connected to the opening at the lower end of the oil filling tank 10, and a limit block 215 is provided at the upper end of the fixed shell 21, and the limit block 215 is used to limit the sliding stroke of the piston 12. Through this arrangement, the power module 20 and the piston 12 can be detachably matched with the oil filling tank 10, so that when the grease in the oil filling tank 10 is used up, grease can continue to be added to the oil filling tank 10, so that the oil injector can be used repeatedly.

[0042] Further reading Figure 2 , Figure 3 and Figure 5In the embodiment of the utility model, the cross-link 25 includes a plurality of cross-groups, each cross-group having a first link 251 and a second link 252 that are crossed and rotatably connected to each other, and two adjacent cross-groups are hinged through the ends of the first link 251 and the second link 252. The structure is simple and can realize the telescopic action driven by the rack group 24.

[0043] Further reading Figure 7 In the embodiment of the utility model, a circuit module (not shown) electrically connected to the power motor 22 is arranged inside the fixed housing 21, and the circuit module is also electrically connected to a time adjustment knob 27, which is exposed outside the fixed housing 21 to facilitate intuitive and convenient operation by the operator; when the operator rotates and adjusts the time adjustment knob 33, a series of electronic signal transmission and processing processes can be triggered. Specifically, through this operation, an oil injection amount control signal corresponding to the adjustment action can be generated, and the signal is accurately transmitted to the circuit module. After receiving this control signal, the circuit module will immediately accurately control the relevant components and mechanisms inside the oiler. Under this precise control, grease can be squeezed out of the oiler in a controllable amount and in an orderly manner. The extruded grease will be accurately applied to the corresponding equipment along the preset channels and paths. Because different equipment has significant differences in the amount of grease required for lubrication, maintenance, etc. during operation. Some equipment may require more grease to ensure adequate lubrication due to high work intensity and high speed; while some equipment only needs a small amount of grease to maintain normal operation due to compact structure and small workload. By setting the time adjustment knob to control the oil output of the oiler, it is possible to flexibly adapt to the diverse and personalized needs of these different equipment for the amount of grease, providing a solid guarantee for the stable operation and efficient work of the equipment; for example, on an automated production line, large-scale mechanical equipment running at high speed may need to adjust the time adjustment knob 33 to a longer oiling time to ensure that a larger amount of grease can be injected each time to ensure adequate lubrication and reduce wear; and for some small auxiliary equipment, it is only necessary to adjust the time adjustment knob 33 to a shorter oiling time and inject a small amount of grease to meet its lubrication needs.

[0044] It is obvious to those skilled in the art that the present invention is not limited to the details of the exemplary embodiments described above, and that the present invention can be implemented in other specific forms without departing from the spirit or basic features of the present invention. Therefore, no matter from which point of view, the embodiments should be regarded as exemplary and non-restrictive, and the scope of the present invention is defined by the appended claims rather than the above description, and it is intended that all changes falling within the meaning and scope of the equivalent elements of the claims are included in the present invention.

Claims

1. An oiler that uses a gear-connecting rod mechanism to generate oil injection power, comprising an oil injection tank (10), an oil injection port (11) disposed on the oil injection tank (10), a piston (12) slidably connected to the inside of the oil injection tank (10) for pushing grease to be extruded from the oil injection port (11), and a power module (20) mounted on the oil injection tank (10) for providing power to the piston (12), characterized in that: The power module (20) comprises a fixed housing (21) fixedly mounted on the oil filling tank (10), a power motor (22) mounted on the fixed housing (21), a gear set (23) drivingly connected to the power motor (22), a rack set (24) slidably connected to the fixed housing (21) and meshing with the gear set (23), and a cross connecting rod (25) docked between the fixed housing (21) and the piston (12) and driven by the rack set (24), wherein the cross connecting rod (25) generates a push-pull force driven by the rack set (24) to drive the piston (12) to slide along the inside of the oil filling tank (10).

2. The oil injector using a gear-link mechanism to generate oil injection power according to claim 1, characterized in that: The two ends of the cross connecting rod (25) respectively have a hinged end and a free end, and the two ends of the cross connecting rod (25) are respectively hinged to the fixed housing (21) and the piston (12) through the hinged ends, and one end of the cross connecting rod (25) is transmission-connected to the rack assembly (24) through the free end.

3. The oil injector using a gear-link mechanism to generate oil injection power according to claim 2, characterized in that: Two groups of cross connecting rods (25) are provided, and the two groups of cross connecting rods (25) are symmetrical to the central axis of the piston (12). The rack group (24) includes a first rack (241) and a second rack (242). The first rack (241) and the second rack (242) are both slidably connected to the fixed housing (21), and the first rack (241) and the second rack (242) are driven by the gear group (23) to slide in opposite directions relative to each other.

4. The oiler using a gear-link mechanism to generate oil injection power according to claim 3, characterized in that: The gear set (23) comprises a power gear (231) that is power-connected to a power motor (22), a reduction gear (232) that is rotationally connected to a fixed housing (21) and meshes with the power gear (231), and an output gear (233) that is rotationally connected to the fixed housing (21) and meshes with the reduction gear (232); a first rack (241) and a second rack (242) are respectively arranged in parallel on both sides of the output gear (233), and the first rack (241) and the second rack (242) are respectively meshed with the output gear (233).

5. The oil injector using a gear-link mechanism to generate oil injection power according to claim 4, characterized in that: The output gear (233) comprises an upper gear (2331) meshed with the reduction gear (232) and a lower gear (2332) coaxially connected to the upper gear (2331), and the first rack (241) and the second rack (242) are respectively meshed with the lower gear (2332).

6. The oil injector using a gear-link mechanism to generate oil injection power according to claim 5, characterized in that: The gear set (23) further comprises a fixed seat (234) mounted inside the fixed housing (21); the drive motor is mounted on the fixed seat (234); the reduction gear (232), the upper gear (2331) and the lower gear (2332) are all rotatably connected to the fixed seat (234); wherein the reduction gear (232) and the upper gear (2331) are all rotatably connected to the upper end of the fixed seat (234); and the lower gear (2332) is rotatably connected to the lower end of the fixed seat (234).

7. The oil injector using a gear-link mechanism to generate oil injection power according to claim 6, characterized in that: A rotating shaft (2333) is provided at the lower end of the upper gear (2331), and the upper gear (2331) is rotatably connected to the upper end of the fixed seat (234) via the rotating shaft (2333), and a square block (2334) is provided at the lower end of the rotating shaft (2333), and a square sleeve (2335) matching the square block (2334) is provided at the upper end of the lower gear (2332), and the upper gear (2331) and the lower gear (2332) are coaxially docked by docking the square block (2334) and the square sleeve (2335).

8. An oiler using a gear-link mechanism to generate oil injection power according to any one of claims 3 to 7, characterized in that: The fixed housing (21) comprises an upper housing (211) and a lower housing (212) which are butt-jointed with each other. A flat window (213) corresponding to the cross-linking rod (25) is arranged on the upper housing (211). The cross-linking rod (25) extends into the fixed housing (21) along the flat window (213). The hinged end of the cross-linking rod (25) is hinged inside the flat window (213). When the upper housing (211) and the lower housing (212) are fixedly covered, a sliding gap (214) corresponding to between the flat window (213) and the gear set (23) is formed between the two. The first rack (241) and the second rack (242) both have a sliding portion (243) sliding in the sliding gap (214) and a rack portion (244) formed on one side of the sliding portion (243) and meshing with the gear set (23). The sliding portion (243) is hinged to the free end of the cross-linking rod (25).

9. The oil injector using a gear-link mechanism to generate oil injection power according to claim 1, characterized in that: The lower end of the oil filling tank (10) is provided with an opening, the fixed housing (21) is threadedly connected to the opening at the lower end of the oil filling tank (10), and a limit block (215) is provided at the upper end of the fixed housing (21), the limit block (215) being used to limit the sliding stroke of the piston (12).

10. The oil injector using a gear-link mechanism to generate oil injection power according to claim 1, characterized in that: A circuit module electrically connected to the power motor (22) is arranged inside the fixed housing (21), and the circuit module is also electrically connected to a time adjustment knob (27), and the time adjustment knob (27) is exposed outside the fixed housing (21).

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