Transmission assembly for hair trimmer and hair trimmer

Abstract

The invention discloses a transmission assembly for a hair trimmer and the hair trimmer. The hair trimmer comprises a base assembly, a transmission assembly and a tool bit assembly. The transmission assembly comprises a mounting base, a cover plate, a flexible plate, a limiting nail, a movable plate, a rotating plate, a driving block, a driven block and a driving rod. The cover plate is provided with a fixing column and a mounting hole. And the center of the rotating plate is rotationally arranged on the fixed column. A strip-shaped groove is formed in the end, facing the mounting base, of the driving block. The two ends of the rotating plate penetrate through the first kidney-shaped holes of the two movable plates correspondingly and are inserted into the second kidney-shaped holes of the driving block and the second kidney-shaped holes of the driven block correspondingly, and when one movable plate moves in a reciprocating mode, the rotating plate is driven to drive the other movable plate to move in a reciprocating mode. The two movable plates can slide in the opposite moving directions at the same time, staggered movement of multiple tool bits is achieved, and the shearing effect is improved.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of beard trimming devices, in particular to a transmission assembly for a hair trimmer and a hair trimmer. BACKGROUND

[0002] A shaver or hair clipper is a grooming appliance that uses electric power to drive a blade to cut beard and hair, mainly divided into rotary and reciprocating types. The rotary shaver works by rotating the center, continuously cutting the beard in circular motion, with low noise and comfort, while the reciprocating shaver moves the blade head left and right, with more vibration and noise, but stronger shaving force.

[0003] ‌An electric shaver is composed of a stainless steel mesh cover, an inner blade, a micro motor and a shell. The mesh cover is a fixed outer blade with many holes, and the beard can extend into the hole. The micro motor is driven by electric energy, which drives the inner blade to move, and uses the shearing principle to cut the beard extending into the hole. The shaver in the prior art, such as the reciprocating electric shaver disclosed in application No. CN202210092634.9, comprises a cutting knife group composed of an outer knife and an inner knife slidingly contacting the inner surface of the outer knife, a motor, a vibration piece driving the inner knife to reciprocate left and right, and a power conversion mechanism between the vibration piece and the motor for converting the rotary force of the motor into reciprocating power. The power conversion mechanism includes an eccentric wheel mounted on the output shaft of the motor and having an eccentric shaft, a drive sub connected directly or indirectly to the vibration piece, and a drive sub made of a micro elastic material, the lower part of which is provided with a matching groove in flexible cooperation with the eccentric shaft. The damping between the matching groove left and right side matching wall of the drive sub and the eccentric shaft is greater than the friction damping between the inner knife and the outer knife of the cutting knife group, so as to realize the power conversion output reciprocating power to drive the vibration piece. However, the transmission structure in the prior art is directly connected with the inner knife of the cutting knife group through the eccentric shaft, which leads to unstable connection, and one eccentric shaft drives one cutting knife group to reciprocate, which is difficult to realize the staggered movement of multiple blade heads.

[0004] In order to solve the above technical problems, the prior art provides a transmission structure for a hair clipper, which is disclosed in a patent application with the application number 202410140737.7. In the technical solution disclosed in the patent application, a transmission body is arranged on two guide shafts, and when a driving device drives the transmission body to move, the transmission body will reciprocate along the two guide shafts. As known, for a hair clipper or a shaver, noise is a parameter that must be controlled and is given priority, because the hair clipper or shaver is very close to the user's ear when in use, and according to the national standard, the noise must be less than 75 decibels. Therefore, in order to reduce the noise, the gap between the guide shaft and the hole on the transmission body for passing the guide shaft is very small, usually less than 0.02 mm. If the gap is greater than 0.02 mm, vibration will be generated, and the noise generated by the vibration will be greater than 75 decibels. At the same time, the guide shaft must have two, because only one guide shaft cannot determine the plane in which the transmission body is located. Under this premise, many technical problems arise. First, the coaxiality of the two guide shafts must be very high, and the guide shaft and the hole are in surface contact, so the coaxiality must be less than 0.02, otherwise the transmission body will be blocked and cannot move. Second, the straightness of the hole arranged on the transmission body must also be very high, and must also be less than 0.02. As mentioned above, if the gap is greater than 0.02, noise greater than 75 decibels will be generated. Third, the surface roughness of the guide shaft and the hole must also be very high. If there is a little unevenness or particles on the basis of a gap of less than 0.02 mm, the transmission body will not be able to move, and the surface roughness of the hole is difficult to guarantee, even if it can be guaranteed, the manufacturing cost will be greatly increased. Fourth, the straightness of the guide shaft must also be very high, and if it is slightly curved, the transmission body will be blocked and cannot move. Fifth, due to the small gap and the influence of errors, the gap will be even smaller. In summer, it is easy to cause seizure due to the difference in thermal expansion and cold contraction coefficients between metal parts and plastic parts, and in winter, the gap will increase and generate noise. Sixth, the accuracy requirements of the above four points result in that in production, it is often difficult to strike a balance, and it is very easy to be stuck or seized, making it difficult to improve the yield and the cost is high. At the same time, due to the above-mentioned several shortcomings, the output power of the driving motor must be larger, because the fit between the transmission body and the guide shaft is often very tight, and a larger force is needed to drive the transmission body to slide on the guide shaft, which will further increase the noise and power consumption of the motor, and reduce the battery usage time after each charge. SUMMARY

[0005] Therefore, the present application provides a transmission assembly for a hair trimmer and a hair trimmer to solve the above technical problems.

[0006] A transmission assembly for a hair trimmer includes a cover plate, at least a pair of spaced-apart locating pins on the cover plate, at least one movable plate movably inserted into the locating pins, and at least one drive block disposed on the movable plate. Each locating pin has a locating groove. Each movable plate has a positioning groove at each end. Each positioning groove is movably engaged with the locating groove of one of the locating pins. The sidewall of the positioning groove contacts the sidewall of the locating groove in a line contact direction perpendicular to the axial direction of the locating groove. The drive block drives the movable plate to move between the pair of locating pins.

[0007] Furthermore, the limiting groove is annular.

[0008] Furthermore, the positioning groove is a square groove.

[0009] Furthermore, the drive block includes a strip groove disposed opposite to the movable plate, the extension direction of the strip groove being perpendicular to the moving direction of the movable plate.

[0010] A hair trimmer having the transmission components described above includes a base assembly and at least two transmission components disposed on the base assembly, each transmission component including a drive device that drives the at least two transmission components to move together.

[0011] Furthermore, the driving device includes a drive motor and an eccentric shaft disposed on the drive motor. The eccentric shaft includes a central shaft section and an eccentric section connected to the central shaft section. The central shaft section of the eccentric shaft is connected to the output end of the drive motor, and the eccentric section of the eccentric shaft is inserted into the strip groove.

[0012] A hair trimmer having the transmission components described above includes a base assembly, at least two transmission components disposed on the base assembly, and at least two rotating plates disposed in the transmission components. At least two fixed posts for rotatably arranging the rotating plates are spaced apart on the cover plate. The center of each rotating plate is rotatably disposed on the fixed posts and includes two spaced-apart connecting shafts. Each of the rotating plates has a first oblong hole at both ends, the first oblong hole being located between the positioning groove and the center of the rotating plate. Each connecting shaft passes through the first oblong holes of two of the rotating plates.

[0013] Furthermore, the hair trimmer also includes a driven block disposed on another of the transmission components, the driven block being disposed on the movable plate of the other transmission component.

[0014] Further, the base assembly comprises a handle and a base arranged on the handle.

[0015] Compared with the prior art, the transmission assembly for the hair trimmer provided by the present application has the following advantages. The two positioning grooves at the two ends of the two movable plates are respectively slidably arranged on the limiting grooves of the limiting nails, so that the movable plates can slide along the positioning grooves under the driving of the driving motor. Since the contact between the side wall of the positioning groove and the side wall of the limiting groove is linear contact in the axial direction perpendicular to the limiting groove, the gap precision between the side wall of the positioning groove and the side wall of the limiting groove can be easily ensured to be less than 0.02 mm, and therefore the arrangement direction of the central axes of the two limiting nails in the activity direction of the movable plate can be parallel or not parallel to the arrangement direction of the central axes of the other two limiting nails, so as to help improve the product yield and reduce the production cost. In addition, the gap precision between the movable plate and the limiting groove in the thickness direction of the movable plate can also be easily ensured to be within 0.02 mm through machining. Meanwhile, the gap precision between the side wall of the positioning groove and the side wall of the limiting groove in the axial direction perpendicular to the limiting groove has no correlation with the gap precision between the movable plate and the limiting groove in the thickness direction of the movable plate, so that the precision can be easily controlled through machining and is hardly affected by thermal expansion and cold contraction. This not only helps improve the product yield and reduce the cost, but also reduces the output power of the driving motor due to the small sliding resistance, so as to achieve the purpose of prolonging the use time of the battery. BRIEF DESCRIPTION OF DRAWINGS

[0016] Figure 1 An exploded structural schematic view of a transmission assembly provided for the first embodiment of the present application.

[0017] Figure 2 An exploded structural schematic view of the transmission assembly from another angle. Figure 1

[0018] Figure 3 A sectional structural schematic view of the transmission assembly. Figure 1

[0019] Figure 4 A structural schematic view of a hair trimmer provided for the second embodiment of the present application.

[0020] Figure 5 An exploded structural schematic view of the hair trimmer. Figure 4

[0021] A structural schematic view of the transmission assembly possessed by the hair trimmer. Figure 6 Figure 4

[0022] Figure 7 An exploded structural schematic view of the hair trimmer.​​​​Figure 4 An exploded view of the transmission components of a hair trimmer.

[0023] Figure 8 for Figure 4 An exploded view of the transmission components of a hair trimmer from another angle.

[0024] Figure 9 for Figure 4 A schematic diagram of the structure of the transmission component of the hair trimmer, including the removal mounting base.

[0025] Figure 10 for Figure 4 An exploded view of the blade assembly of a hair trimmer. Detailed Implementation

[0026] The following provides a more detailed description of specific embodiments of the present invention. It should be understood that the description of the embodiments of the present invention herein is not intended to limit the scope of protection of the present invention.

[0027] like Figures 1 to 3 The diagram shows a structural schematic of a transmission assembly for a hair trimmer according to a first embodiment of the present invention. The transmission assembly includes a base 10, a cover plate 11 disposed on the base 10, at least a pair of spaced-apart limiting pins 12 on the cover plate 11, at least one movable plate 13 movably inserted into the limiting pins 12, at least one driving block 14 disposed on the movable plate 13, and a driving device 15 for driving the moving block 14. It is conceivable that the transmission assembly also includes other functional modules, such as a power supply, assembly components, installation components, etc., which are technologies well known to those skilled in the art and will not be described in detail here.

[0028] The base 10 is used to support or accommodate the various components mentioned above, such as the cover plate 11, the movable plate 13, etc. Therefore, the structure of the base 10 should preferably be able to install or assemble the various components mentioned above, which will not be described in detail here. In this embodiment, the base 10 is a groove-shaped structure, and the bottom has a through hole 101 for inserting the input end of the drive device 15.

[0029] The cover plate 11 is arranged on the base 10, and at least one pair of mounting holes 111 and at least one through hole 112 are arranged on the side of the cover plate 11 facing the movable plate 13. The mounting holes 111 are used to fix the limiting pins 12, that is, a pair of limiting pins 12 are respectively fixed in the mounting holes 111. Of course, it is conceivable that when there are two pairs or more than two pairs of limiting pins 12, the mounting holes 111 should also have two pairs or more than two pairs, and the specific arrangement will be described in detail in the second embodiment. The through hole 112 is used to pass the driving rod 132 arranged on the movable plate 13, which will be described in detail below.

[0030] The limiting pin 12 has at least one pair, that is, two, and is arranged and fixed in the mounting hole 111. The number of limiting pins 12 can be multiple pairs, such as two pairs or more than two pairs. In this embodiment, the limiting pin 12 has one pair. Each limiting pin 12 is provided with a limiting groove 121, and the limiting groove 121 can be a circular ring. The limiting pin 12 can be made of metal material, which can be machined to ensure its accuracy, that is, to ensure the diameter of the center axis of the limiting groove 121 and the width of the limiting groove 121. The specific size accuracy of the limiting groove 121 will be described together with the movable plate 13.

[0031] The movable plate 13 is also made of metal, so that its accuracy can be ensured by machining. The movable plate 13 is provided with a positioning groove 131 at each end, that is, one movable plate 13 has two positioning grooves 131. Therefore, the two positioning grooves 121 of the movable plate 13 are respectively inserted into the limiting grooves 121 of the two limiting pins 12.

[0032] The positioning groove 131 is a square groove, so that the contact between the positioning groove 131 and the side wall of the limiting groove 121 is a line contact. Of course, it is conceivable that the shape of the positioning groove 131 can also be other structures, but it is required to ensure that the contact between the positioning groove 131 and the side wall of the limiting groove 121 is a line contact. Since the contact between the positioning groove 131 and the side wall of the limiting groove 121 is a line contact, the control of its accuracy is much lower than that of the face contact in the prior art, and both the positioning groove 131 and the limiting groove 121 can be machined, and their accuracy is very easy to control, so that the gap between the positioning groove 131 and the limiting groove 121 can be easily controlled to be less than 0.02 mm.

[0033] Although the movable plate 13 is in surface contact with the limiting groove 121 in the thickness direction, the thickness of the movable plate 13 and the width of the limiting groove 121 are easily controlled to be less than 0.02mm by machining, and thus the gap between the movable plate 13 and the limiting groove 121 in the thickness direction is also easily controlled to be less than 0.02mm. It should be noted that the precision control is the common knowledge of machining technicians in the field.

[0034] When the two positioning grooves 131 are respectively inserted between the two limiting grooves 121, since the limiting groove 121 is a circular ring and the contact between the positioning groove 131 and the limiting groove 121 is linear contact, the precision between the arrangement direction of the two positioning grooves 131 and the arrangement direction of the central axes of the two limiting posts 12 is not required, i.e. the arrangement direction of the two positioning grooves 131 and the arrangement direction of the central axes of the two limiting posts 12 can be parallel or have a small angle due to machining error. That is, even if there is a small angle, the movable plate 13 cannot be stuck or even locked because the contact between the positioning groove 131 of the movable plate 13 and the limiting groove 121 is linear contact, and the movable plate 12 can rotate a small angle. The small angle will not cause the transmission assembly to be unable to work, such as being stuck or locked, and will not be affected by thermal expansion and contraction.

[0035] Based on the above description, the precision control between the movable plate 13 and the limiting post 12 only has two factors, i.e. the gap precision between the side wall of the positioning groove 131 and the side wall of the limiting groove 121, and the gap precision between the movable plate 13 in the thickness direction and the limiting groove 121, and there is no mutual restriction between the two gap precisions, so it is very easy to control the precision, which not only helps to improve the yield of the product and reduce the cost, but also can reduce the output power of the driving device 15 because of the small sliding resistance, so as to achieve the purpose of prolonging the use time of the battery.

[0036] The side of the movable plate 13 facing the cover plate 11 is also provided with at least one driving rod 132. In the embodiment, the driving rod 132 has two. The driving rod 132 passes through the perforation 112 and is connected with a cutter head assembly (not shown in the figure), so as to drive the cutter head assembly to work to shave when the movable plate 13 reciprocates.

[0037] The driving block 14 is fixedly arranged on the movable plate 13. The driving block 14 is provided with a strip-shaped slot 141 on the side facing the driving device 15. The strip-shaped slot 141 extends perpendicularly to the moving direction of the movable plate 13, i.e. perpendicularly to the arrangement direction of the two positioning slots 131. When the eccentric section 152 of the eccentric shaft 151 of the driving device 15 is inserted into the strip-shaped slot 141, the moving distance of the output shaft 151 in the direction perpendicular to the moving direction of the movable plate 13 is eliminated by the strip-shaped slot 141, so that only the driving block 14 is driven to move reciprocally along the moving direction of the movable plate 13. The driving block 14 is usually made of plastic, which can be directly injection molded with the movable plate 13 by an injection molding process, so that the movable plate 13 is fixed in the driving block 14.

[0038] The driving device 15 can be a driving motor 150, and the output end of the driving motor 150 is provided with an eccentric shaft 151. The eccentric shaft 151 comprises an eccentric section 153 and a middle shaft section 152 connected with the eccentric section 153. The middle shaft section 152 of the eccentric shaft 151 is connected with the output end of the driving motor 150, i.e. the middle shaft section 152 is coaxially arranged with the output end of the driving motor 150, and the eccentric section 153 of the eccentric shaft 151 is arranged non-coaxially with the middle shaft section 152, so as to form an eccentric wheel structure. The eccentric section 153 is inserted into the strip-shaped slot 141. In working, when the driving motor 150 drives the eccentric shaft 151 to rotate, the eccentric section 153 of the eccentric shaft 151 will perform a circular motion, and then drives the movable plate 13 to move reciprocally. When the movable plate 13 moves reciprocally, the cutter head (not shown) can be driven to move reciprocally, so as to achieve the purpose of shaving.

[0039] As Figures 4 to 10 A structure diagram of a beard shaver with the transmission assembly is provided for the second embodiment of the present application. The beard shaver with the transmission assembly comprises a base assembly 40, a transmission assembly 20 arranged on the base 40, and a cutter head assembly 30 arranged on the transmission assembly 20. It is conceived that the hair trimmer further comprises other functional modules, such as an assembling assembly, an electrical connection assembly, and a battery assembly, etc., which are the known technologies for the person skilled in the art, and will not be described herein.

[0040] The base assembly 40 comprises a handle 41 and a base 42 arranged on the handle 10.

[0041] The handle 41 is used to carry each functional module described above, and is provided with various functional structures such as screws, bolts and the like to complete the installation and assembly of the functional modules, which can be set according to actual needs, and will not be described in detail here.

[0042] The base 42 is fixedly arranged on the handle 41 and is used to mount the transmission assembly 20, and thus its structure and shape are subject to the installation of the transmission assembly 20, and will not be described here.

[0043] The transmission assembly 20 comprises a mounting seat 21 arranged on the base 42, a cover plate 22 arranged on the mounting seat 21, a flexible plate 23 arranged on the cover plate 22, at least two pairs of limiting pins 24 arranged on the cover plate 22, at least two movable plates 25 arranged on the cover plate 22, at least two rotating plates 26 arranged on the cover plate 22, a driving block 27 arranged on one of the movable plates 25, a driven block 28 arranged on the remaining movable plates 25, and at least one driving device 29 for driving the driving block 27 to move.

[0044] Both ends of the mounting seat 21 can be rotatably arranged or fixedly connected with the base 42. When rotatably arranged, the transmission assembly 20 and the cutter head assembly 30 arranged thereon can be rotated to match the part of the body to be shaved, so that the cutter head assembly 30 can closely match the skin and ensure that no corner is missed during shaving.

[0045] The cover plate 22 has the same structure as the cover plate 11 of the first embodiment, except that it has two through holes for driving rods 253. One end of the cover plate 22 towards the mounting seat 21 is provided with at least two fixed columns 221 for rotatably arranging the rotating plates 26, and at least four mounting holes 222 for arranging the limiting pins 24. The fixed columns 221 are used to assemble the rotating plates 26, so that the rotating plates 26 can rotate around the fixed columns 221. The mounting holes 222 are used to mount and fix the limiting pins 24, i.e. the limiting pins 24 are respectively fixedly inserted into the mounting holes 222.

[0046] The flexible plate 23 is arranged on the middle part of the cover plate 22, and at least two through holes 231 arranged in a straight line are arranged on the flexible plate 23. The through holes 231 are used for penetrating the driving rods 253 arranged on the movable plate 25. The flexible plate 23 is made of flexible material, so that the movement of the driving rods 253 is not affected, and the gap between the driving rods 253 and the cover plate 22 can be sealed by the flexible plate 23, so as to avoid the beard residues from falling into the transmission assembly 20 and affecting the normal operation of the transmission.

[0047] The number of the limiting nails 24 is determined according to the number of the movable plates 25. In this embodiment, since the movable plate 25 has two, the limiting nail 24 has four. Each limiting nail 24 is provided with a limiting groove 241, and the limiting groove 241 can be a circular ring. The four limiting nails 24 are arranged in a rectangular distribution and are fixedly inserted into the mounting holes 222. The limiting nail 24 is made of metal material, and its precision can be ensured by machining, that is, the diameter of the central axis of the limiting groove 241 and the width of the limiting groove 241 are ensured. The specific dimensional accuracy of the limiting groove 241 will be described together with the movable plate 25.

[0048] The two movable plates 25 are arranged side by side, and the arrangement direction of the two movable plates 25 is parallel to the arrangement direction of the plurality of through holes 231. The two movable plates 25 have the same structure, and each movable plate 25 is also made of metal, so that the precision can be ensured by machining. Each movable plate 25 is provided with a positioning groove 251 at each end, that is, each movable plate 25 has two positioning grooves 251. Therefore, the two positioning grooves 251 of each movable plate 25 are respectively inserted into the limiting grooves 241 of the two limiting nails 24.

[0049] The positioning groove 251 can be a square groove, so that the contact between the positioning groove 251 and the side wall of the limiting groove 241 is a line contact. Since the contact between the positioning groove 251 and the side wall of the limiting groove 241 is a line contact, the control of the precision is much lower than that of the surface contact. Moreover, the positioning groove 251 and the limiting groove 241 can be machined, and the precision is also very easy to control, so that the gap precision between the positioning groove 251 and the limiting groove 241 can be easily controlled below 0.02 mm.

[0050] Although the movable plate 25 is in surface contact with the limiting groove 241 in the thickness direction, the thickness of the movable plate 25 and the width of the limiting groove 241 can also be easily controlled below 0.02 mm by machining, so that the gap between the movable plate 25 and the limiting groove 241 in the thickness direction can also be easily controlled below 0.02 mm.

[0051] When the two positioning slots 251 are respectively inserted between the two limiting slots 241, since the limiting slots 241 are circular and the contact between the positioning slots 251 and the limiting slots 241 is linear, the precision between the arrangement direction of the central axes of the two limiting posts 24 inserted on one movable plate 25 and the arrangement direction of the central axes of the two limiting posts 24 inserted on another movable plate 25 is not required, i.e. the arrangement direction of the central axes of the two limiting posts 24 and the arrangement direction of the central axes of the other two limiting posts 24 can be parallel or have a small angle due to machining error in the moving direction of the movable plate 25. That is, even if there is a small angle, any movable plate 25 cannot be fixed because the contact between the positioning slots 251 and the limiting slots 241 is linear and the movable plate 25 can rotate a small angle. The small angle will not cause the tool head assembly 30 to be unable to work, such as being stuck or locked, but only can deform the two parallel blades of the tool head assembly 30 into a scissors-like blade, which will not affect hair cutting or shaving.

[0052] Based on the above description, the precision control between the movable plate 25 and the limiting post 24 only has two factors, i.e. the gap precision between the side wall of the positioning slot 251 and the side wall of the limiting slot 241 and the gap precision between the movable plate 25 in the thickness direction and the limiting slot 241, and there is no mutual restriction between the two gap precisions, so it is very easy to control the precision, which not only helps to improve the yield of the product and reduce the cost, but also can reduce the output power of the driving motor 150 because of the small sliding resistance, thereby achieving the purpose of prolonging the use time of the battery.

[0053] The sliding direction of the movable plate 25 is perpendicular to the arrangement direction of the plurality of perforations 231. Each movable plate 25 is provided with a first waist-shaped hole 252 at each end. The first waist-shaped hole 252 is located between the positioning slot 251 and the center of the movable plate 25. The first waist-shaped hole 252 is used for inserting the connecting shaft 261 on the rotating plate 26, which will be described in detail below in cooperation with the connecting shaft 261.

[0054] At least one driving rod 253 should be arranged on each movable plate 25. In this embodiment, two driving rods 253 are arranged on each movable plate 25 to drive the following first cutting mechanism 32 and second cutting mechanism 33 of the cutter head assembly 30 to move in opposite directions. The driving rods 253 are arranged on the movable plates 25 in pairs respectively, and the free ends of the driving rods 253 pass through the perforations 231 of the flexible plate 23 and are inserted into the cutter head assembly 30. The movement of the two movable plates 25 can drive one end of the driving rod 253 to move, thereby driving the other end inserted into the cutter head assembly 30 to reciprocate, so as to realize the movement of the moving blade in the cutter head assembly 30. The specific description will be given below in combination with the cutter head assembly 30.

[0055] The two rotating plates 26 have the same structure, and the central positions of each rotating plate 26 are rotatably arranged on the fixed column 221. Two connecting shafts 261 are arranged at the two ends of each rotating plate 26 respectively. The two connecting shafts 261 of one of the rotating plates 26 are inserted into one of the first waist-shaped holes 252 of the two movable plates 25 respectively, and the two connecting shafts 261 of the other rotating plate 26 are inserted into the other first waist-shaped holes 252 of the two movable plates 25 respectively.

[0056] When one of the movable plates 25 moves reciprocally, one end of the rotating plate 26 is driven to move in an arc, so that the other end of the rotating plate 26 moves in an arc in the opposite direction, thereby driving the other movable plate 25 to move reciprocally, realizing the sliding of the two movable plates 25 in opposite directions. In addition, since the rotating plate 26 rotates and the movable plate 25 moves horizontally, in order to avoid the problem of mutual interference, the first waist-shaped hole 252 has a certain movable space to avoid mutual interference.

[0057] The driving block 27 is fixedly arranged on one of the movable plates 25. The driving block 27 is provided with a strip-shaped slot 271 at one end thereof facing the mounting base 21. The strip-shaped slot 271 extends perpendicularly to the moving direction of the movable plate 25, i.e. parallel to the arrangement direction of the two movable plates 25. The eccentric segment 132 of the eccentric shaft 13 is inserted into the strip-shaped slot 271, and the strip-shaped slot 271 eliminates the moving distance of the eccentric shaft 13 in the direction perpendicular to the moving direction of the movable plate 25, so that only the driving block 27 is driven to move reciprocally along the moving direction of the movable plate 25. The driven block 28 is fixedly arranged on the other movable plate 25. The two ends of the driving block 27 are respectively provided with a waist-shaped hole corresponding to the first waist-shaped hole 252, and the two ends of the driven block 28 are also respectively provided with a waist-shaped hole corresponding to the first waist-shaped hole 252. The two connecting shafts 261 of the rotating plate 26 pass through the first waist-shaped hole 252 and the waist-shaped holes of the driving block 27 and the driven block 28.

[0058] The driving device 29 has the same structure and function as the driving device 15 of the first embodiment, and will not be described here.

[0059] The cutter head assembly 30 itself is a prior art, which comprises a cutter seat 31 arranged on the mounting base 21, two first cutting mechanisms 32 arranged on the cutter seat 31, and two second cutting mechanisms 33 arranged on the cutter seat 31.

[0060] The cutter seat 31 is provided at the bottom with four sliding grooves 311 for providing moving space for the driving rods 253. The driving rods 253 pass through the sliding grooves 311 and are inserted into the first cutting mechanisms 32 or the second cutting mechanisms 33. The first cutting mechanisms 32 and the second cutting mechanisms 33 are used for trimming beard or hair, the first cutting mechanisms 32 are used for cutting long hair such as long beard, and the second cutting mechanisms 33 are used for cutting short hair such as short beard. The structure of the first cutting mechanisms 32 and the second cutting mechanisms 33 is the same as the cutter head and the blade assembly and cutting unit in the hair trimmer in the patent with the patent number CN202322096770.8 and the patent name Hair Trimmer, and beard or hair inserted between the moving cutter and the static cutter is cut off through the reciprocating movement of the moving cutter. The structure and principle thereof should be a prior art, and will not be described here. The reciprocating movement of the moving cutter is realized through the reciprocating movement of the driving rods 253, i.e. the two driving rods 253 on one of the movable plates 25 are connected with one first cutting mechanism 32 and one second cutting mechanism 33 respectively, and the two driving rods 253 on the other movable plate 25 are connected with the other first cutting mechanism 32 and the other second cutting mechanism 33 respectively, so that one movable plate 25 drives one first cutting mechanism 32 and one second cutting mechanism 33.

[0061] In addition, it is conceivable that when the transmission assembly 20 has two movable plates 25, the two movable plates 25 can also move in the same direction, i.e., the movable plates move in the same direction at the same time, at which time the driving blocks 27 are fixed on the two movable plates 25, i.e., the two movable plates 25 and the driving blocks 27 are formed together by the injection molding process, i.e., without the driven blocks 28. At this time, the driving device 29 drives the two movable plates 25 to move together. Through the description of the second embodiment, those skilled in the art should understand the working principle when the two movable plates 25 move in the same direction, so no additional drawings are provided for illustration.

[0062] Compared with the prior art, the transmission assembly for the hair trimmer provided by the present application can slide along the positioning groove 251 under the driving of the driving motor 150 by slidably arranging the two ends of the two movable plates 25 in the positioning grooves 251 of the limiting nails 24, respectively. Since the contact between the side wall of the positioning groove 251 and the side wall of the limiting groove 241 in the axial direction perpendicular to the limiting groove 241 is a line contact, the gap precision between the side wall of the positioning groove 251 and the side wall of the limiting groove 241 can be easily ensured to be less than 0.02 mm, and therefore the arrangement direction of the center axes of the two limiting nails 24 in the activity direction of the movable plate 25 can be parallel or not parallel to the arrangement direction of the center axes of the other two limiting nails 24, thereby helping to improve the product yield and reduce the production cost. In addition, the gap precision between the movable plate 25 and the limiting groove 241 in the thickness direction of the movable plate 25 can also be easily ensured to be within 0.02 mm by machining. At the same time, the gap precision between the side wall of the positioning groove 251 and the side wall of the limiting groove 241 in the axial direction perpendicular to the limiting groove 241 has no correlation with the gap precision between the movable plate 25 and the limiting groove 241 in the thickness direction of the movable plate 25, so the machining precision can be easily controlled, and the influence of thermal expansion and cold contraction is very small. This not only helps to improve the product yield and reduce the cost, but also can reduce the output power of the driving motor 150 because of the small sliding resistance, thereby achieving the purpose of prolonging the use time of the battery.

[0063] The above is only a preferred embodiment of the present application, and is not used to limit the protection scope of the present application. Any modification, equivalent replacement, or improvement within the spirit of the present application is covered by the claim scope of the present application.

Claims

1. A transmission assembly for a hair trimmer, characterized in that: The transmission assembly includes a cover plate (11, 22), at least a pair of limiting pins (12, 24) spaced apart on the cover plate (11, 22), at least one movable plate (13, 25) movably inserted on the limiting pins (12, 24), and at least one driving block (14, 27) disposed on the movable plate (13, 25). Each limiting pin (12, 24) is provided with a limiting groove (121, 241), and each movable plate (13, 25) has a limiting groove at both ends. A positioning groove (131, 251) is provided, and each positioning groove (131, 251) is movably engaged in the limiting groove (121, 241) of a limiting pin (12, 24). The sidewall of the positioning groove (131, 251) and the sidewall of the limiting groove (121, 241) are in line contact in the axial direction perpendicular to the limiting groove (121, 241). The driving block (14, 27) drives the movable plate (13, 25) to move between a pair of limiting pins (12, 24).

2. The transmission assembly as described in claim 1, characterized in that: The limiting grooves (121, 241) are annular.

3. The transmission assembly as described in claim 1, characterized in that: The positioning grooves (131, 251) are square grooves.

4. The hair trimmer as described in claim 1, characterized in that: The drive block (14, 27) includes a strip groove (141, 271) facing away from the movable plate (13, 25), and the extension direction of the strip groove (141, 271) is perpendicular to the moving direction of the movable plate (13, 25).

5. A hair trimmer having a transmission assembly as claimed in any one of claims 1 to 4, characterized in that: The hair trimmer includes a base assembly (40) and at least two transmission assemblies (20) disposed on the base assembly (40). Each transmission assembly (20) includes a drive device (15, 29) that drives at least two of the transmission assemblies (20) to move together.

6. The hair trimmer as described in claim 5, characterized in that: The drive device (15, 29) includes a drive motor (150) and an eccentric shaft (151) disposed on the drive motor (150). The eccentric shaft (151) includes a central shaft section (152) and an eccentric section (153) connected to the central shaft section (152). The central shaft section (152) of the eccentric shaft (151) is connected to the output end of the drive motor (150), and the eccentric section (153) of the eccentric shaft (151) is inserted into the strip groove (141, 271).

7. A hair trimmer having a transmission assembly as claimed in any one of claims 1 to 4, characterized in that: The hair trimmer includes a base assembly (40), at least two transmission assemblies (20) disposed on the base assembly (40), and at least two rotating plates (26) disposed in the transmission assemblies (20). The cover plate (22) is provided with at least two fixed posts (221) for rotating the rotating plates (26) at intervals. The center of the rotating plate (26) is rotatably disposed on the fixed posts (221) and includes two connecting shafts (261) disposed at intervals. Each of the movable plates (25) is provided with a first waist-shaped hole (252) at both ends. The first waist-shaped hole (252) is located between the positioning groove (251) and the center position of the movable plate (25). Each connecting shaft (261) passes through the first waist-shaped hole (252) of the two movable plates (25).

8. The hair trimmer as described in claim 6, characterized in that: The hair trimmer also includes a driven block (28) disposed on another of the transmission components (20), the driven block (28) being disposed on the movable plate (25) of the other transmission component (20).

9. The hair trimmer as described in claim 7, characterized in that: The base assembly (40) includes a handle (41) and a base (42) disposed on the handle (41).

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