JP5810449B2 - Vacuum cleaner head - Google Patents

Description

  The present invention relates to a cleaner head having a stirrer and a drive assembly for driving the stirrer.

  The cleaner head of an appliance such as a vacuum cleaner or floor cleaner includes an agitator that is driven by a drive assembly. The drive assembly often includes a dock that transmits torque generated by the drive assembly to the agitator.

  The problem with existing vacuum cleaner heads is that there may be some play between the dock and the stirring device. As a result, when the stirring device rotates, the stirring device vibrates and generates noise.

  The present invention relates to a cleaner head, which includes a stirrer and a drive assembly that drives the stirrer, and the drive assembly includes a dock that transmits torque to the stirrer. One has a tapered head, a shank extending from the tapered head, and a thread formed around the shank, and the other of the dock and the stirring device is a bore including a chamfer, and a wall of the bore A complementary thread formed around the shank, the shank projecting into the bore, and the thread and the complementary thread are screwed into the dock when the dock is rotated. A vacuum cleaner head is provided that meshes with each other such that the tapered heads mesh with the chamfer.

  When the chamfer is engaged with and tightened to the tapered head, play between the dock and the agitator is removed or reduced. As a result, the agitator is less susceptible to vibration during rotation, thus reducing noise.

  A further problem with existing vacuum cleaner heads is that the stirring device may not align coaxially with the dock. As a result, the unbalanced force imparts high stress to the vacuum head components, particularly the bearings, thereby shortening the life of the vacuum head. In the cleaner head of the present invention, the engagement between the chamfered portion and the tapered head acts to align the stirring device and the dock coaxially. As a result, unbalanced forces are reduced, thus extending the life of the cleaner head.

  Each thread may have a lead angle no greater than 60 degrees. As a result, the axial force that the dock applies to the stirrer reduces the vibration and noise of the stirrer to the tapered head over the torque range normally generated by most conventional cleaner head drive assemblies. It has a size that ensures that it is held with sufficient force.

  Each thread should have a lead angle not less than 40 degrees. As a result, the axial force that the dock exerts on the agitator is large enough to hold the agitator on the dock over the torque range normally generated by most conventional cleaner head drive assemblies. However, it is not excessively large that may cause premature thread failure.

  Each thread may have a plurality of strips. By adopting a plurality of strips, the torque applied by the dock is distributed to a number of strips. As a result, greater torque can be transmitted to the agitator without damaging the threads. In addition, if the stirrer is removable from the cleaner head, a number of strips facilitate the user to install the stirrer. In particular, it is generally easier to align the screw threads of the stirrer and the screw threads of the dock.

  Each strip should be wound over an angle not less than 120 degrees. The length of each strip depends on the angle at which the strip is wound. As the winding angle decreases, the length of the strip also decreases. As a result, the strip is subjected to a greater load per unit length. If the wrap angle is less than 120 degrees, the length of the strip may be insufficient to support the torque required by many cleaner heads.

  Each strip should be wound over an angle not greater than 360 degrees. This has the advantage of maintaining a relatively short shank and bore. In addition, if the stirrer is removable from the cleaner head, the stirrer can be removed from the dock by rotating the stirrer over an angle not greater than 360 degrees, which is less of a stirrer Generally achieved by a number of twists.

  Each thread may have a sawtooth thread form. The saw blade thread configuration has the advantage of relatively small friction characteristics. As a result, for a given torque, a larger axial force acts on the stirring device by the dock. In addition, if the stirrer is removable from the cleaner head, a thread having only a small amount of friction makes it easier for the user to unscrew the stirrer against the dock. Since the load acting on the stirring device varies, the torque generated by the drive assembly also varies. In response to the decrease in torque, the agitator is subjected to a net axial force away from the dock. By adopting the sawtooth thread form, the vertical (or nearly vertical) flank of the thread acts to counter negative axial forces, thus preventing the stirrer and dock from loosening. As a result, when the stirrer is subjected to various loads, the stirrer continues to be held tightened to the dock and thus continues to reduce vibration and noise. In addition, the sawtooth thread form has a thicker base than other thread forms, which results in a relatively strong thread. As a result, the threads can withstand greater axial forces and thus the agitator is held to be tightened by the dock.

  The stirrer can be removed from the cleaner head. In particular, by rotating the stirrer relative to the dock, the screwing of the stirrer is loosened and the stirrer can be separated from the dock. With conventional cleaner heads having removable agitator devices, it is generally difficult to ensure that the agitator device is axially tightened within the cleaner head. With the cleaner head of the present invention, the agitator is screwed to the dock and tightened to the dock to prevent or reduce axial play. As a result, a removable stirring device is provided, usually without the inherent vibration and noise problems.

  The terms used throughout this specification are well understood in the engineering field. One or more terms may not have direct identity in other languages. Therefore, for clarity, some terms are explained. The term “dock” should be understood to mean a torque transmission member. The term “strip” refers to the top of the male thread or the groove of the female thread. The term “lead angle” means the angle formed by a thread of threads with respect to a plane perpendicular to the axis of the screw. The term “thread form” means the cross-sectional shape or cross-sectional profile of a thread strip.

  In order that the present invention may be more readily understood, embodiments thereof will now be described by way of example only with reference to the accompanying drawings.

FIG. 3 is an exploded view of a cleaner head according to the present invention. It is a perspective view of the dock which comprises some vacuum cleaner heads. It is a side view of a dock. It is a cross-sectional view of a dock. It is a cross-sectional view of one end of the stirring device that constitutes a part of the cleaner head.

  The vacuum cleaner head 1 of FIG. 1 has a housing 2, and a stirring device 3 and a drive assembly 4 are mounted in the housing 2.

  The agitator 3 has an elongated body 5 with bristles, flicker strips or other means 6 for agitating the cleaning surface attached to the elongated body 5. One end of the stirring device 3 is attached to a bush 7 seated in a removable cap 8. The other end of the stirring device 3 is attached to a dock 12 that constitutes a part of the drive assembly 4.

  The drive assembly 4 includes an electric motor 10 and a transmission device 11 that transmits torque generated by the electric motor 10 to the stirrer 3. In particular, the transmission device 11 has a dock 12 that engages with the stirring device 3. Accordingly, the dock 12 has a function of transmitting the torque generated by the drive assembly 4 to the stirring device 3. The details of the drive assembly 4 other than the dock 12 are not relevant to the present invention, and drive assemblies that drive the agitation device of the cleaner head are well known. For example, each of the DC24 vacuum cleaner and DC26 vacuum cleaner vacuum heads sold by Dyson has a drive assembly suitable for use with the vacuum cleaner head of the present invention.

  Now, the dock 12, the end of the stirring device 3 that engages with the dock 12, and the manner in which the stirring device 3 and the dock 12 engage so as to transmit torque will be described in detail.

  As shown in FIGS. 2 to 4, the dock 12 has a head 13, a shank 14 extending from the head 13, and a helical thread 15 formed around the shank 14.

  The head 13 tapers in a direction toward the shank 14 and defines a truncated cone side surface that is coaxial with the shank 14.

  The shank 14 extends from the head 13 and has a substantially cylindrical shape.

  The thread 15 is a male thread having four strips or streaks 16 that are equally spaced around the shank 14. Each strip 16 is wound 180 degrees around a screw axis 18. As a result, each strip 16 is finished with a half turn. Further, the screw thread 15 has a lead angle of 50 degrees and forms a saw blade thread form.

  As shown in FIG. 5, one end of the stirring device 3 has a bore 19 having a chamfered portion 20 and a helical thread 21 formed around the wall of the bore 19.

  The chamfer 20 has a frustoconical side that is complementary to the frustoconical side of the tapered head 13 of the dock 12, that is, both frustoconical sides have the same or nearly the same taper angle.

  The thread 21 is a female thread complementary to the male thread 15 of the dock 12. As a result, the thread 21 has four strips or streaks 22 equally spaced around the bore 19, each strip 22 being wound over an angle of 180 degrees. The thread 21 also has a lead angle of 50 degrees and takes the form of a sawtooth thread.

  When the stirring device 3 is attached to the dock 12, the shank 14 of the dock 12 protrudes into the bore 19 of the stirring device 3, and the male thread 15 of the dock 12 is screwed with the female thread 21 of the stirring device 3. Due to the tolerance of the cleaner head 1, there is some play or backlash (both axial and radial) between the agitator 3 and the dock 12.

  During operation of the cleaner head 1, the torque generated by the drive assembly 4 is transmitted to the stirring device 3 via the dock 12. The torque applied by the dock 12 by the threads 15 and 21 applies both the axial force and the rotational force to the stirring device 3. The stirring device 3 is rotated by the rotational force. On the other hand, the stirring device 3 is screwed to the dock 12 and tightened to the dock 12 by the axial force. In this regard, since the screw thread 15 of the dock 12 and the screw thread 21 of the stirring device 3 are directed leftward or rightward, the axial force acts in a direction toward the dock 12. Since the stirring device 3 tightens the dock 12, the chamfered portion 20 meshes with the tapered head 13 and tightens it. As a result, play between the agitator 3 and the dock 12 is removed or greatly reduced, thus reducing the vibration of the agitator 3. In addition to the reduction in play, the meshing between the chamfered portion 20 and the tapered head 13 ensures that the agitator 3 and the dock 12 are concentrically aligned. As a result, the unbalanced force is reduced, thus extending the life of the cleaner head 1.

  The magnitude of the axial force depends in particular on the lead angle of the threads 15, 21. The threads 15 and 21 have a lead angle of 50 degrees. This produces an axial force of sufficient magnitude to ensure that the chamfered portion 20 is fastened to the tapered head 13 with sufficient force to absorb play between the stirrer 3 and the dock 12. As the lead angle increases, the magnitude of the axial force decreases, and thus the chamfer 20 is held on the tapered head 13 with weak tightening. It has been found that the axial force generated when the lead angle exceeds 60 degrees is insufficient to properly clamp the chamfered portion 20 to the tapered head 13. As a result, it was observed that vibration and noise were increased. The magnitude of the axial force also depends on the torque generated by the drive assembly. Accordingly, it is possible to employ a relatively large lead angle that generates a relatively large torque, which is actually desirable. However, a lead angle not exceeding 60 degrees has been found to reduce vibration and noise over the torque range normally generated by most conventional cleaner head drive assemblies (eg, 100 Nmm to 300 Nmm stall torque). It was.

  As the lead angle decreases, the magnitude of the axial force increases. While this has the advantage of further tightening the agitator 3 to the dock 12, the further reduction of vibration and noise is small and negligible. Furthermore, as the axial force increases, the threads 15, 21 are required to withstand larger axial loads and may therefore fail prematurely. It has been found that lead angles smaller than 40 degrees do not reduce vibration and noise over the vibration and noise observed at 40 degrees over the torque range normally generated by most conventional cleaner heads. Nevertheless, if the torque generated by the drive assembly is relatively small, a relatively small lead angle is necessary and desirable to generate the required axial force.

  As shown in FIGS. 4 and 5, the threads 15, 21 are in a sawtooth thread form and provide three major advantages. First, the magnitude of the axial force acting on the stirring device 3 also depends on the friction between the two threads 15, 21. The sawtooth thread form has the advantage of relatively low friction properties. As a result, a relatively large axial force is generated for a predetermined torque. Secondly, during use of the cleaner head 1, the stirring device 3 is subjected to various loads. When the load acting on the stirring device 3 varies, the torque generated by the drive assembly 4 also varies. As the torque generated by the drive assembly 4 decreases, the axial force applied by the dock 12 to the agitator 3 decreases. The chamfered portion 20 and the tapered head 13 are in a compressed state, and therefore apply an axial force in the opposite direction. As a result, in response to a decrease in the torque of the drive assembly 4, the agitator 3 receives a net axial force in a direction away from the dock 12. By adopting the sawtooth thread form, the vertical (or substantially vertical) flank 17, 23 of the thread 15, 21 acts to counter negative axial forces, thus the stirrer 3 and The loosening of the dock 12 is prevented. As a result, when the stirrer 3 is subjected to various loads, the stirrer 3 continues to be held clamped to the dock 12 and thus continues to reduce vibration and noise. Third, the sawtooth thread form has a relatively thick base, thereby producing a relatively strong thread. Thus, the threads 15, 21 can withstand relatively large axial forces.

  Each thread 15, 21 has four strips or streaks 16, 22, and each strip 16, 22 is wound over 180 degrees. One skilled in the art can consider having a different number of strips and / or that the strips are wound over different angles. However, as will now be described, changing the number of strips and / or changing the angle at which the strips are wound has both advantages and disadvantages.

  The strips 16 and 22 have a function of transmitting the torque generated by the drive assembly 4 to the stirring device 3. Accordingly, each of the strips 16 and 22 needs to support a part of the entire torque. If the number of strips 16, 22 decreases, each strip 16, 22 needs to support a larger load and may therefore fail prematurely. This can be addressed by increasing the thread form size and increasing the strength of the strips 16,22. As the number of strips 16, 22 increases, the space available for each strip 16, 22 decreases. In this case, each strip 16, 22 will have a smaller thread form, which tends to compromise the strength of the threads 15, 21. As a result, although each strip 16,22 only needs to support a smaller load, the strength of each strip 16,22 may be weakened to the extent that failure of the strip 16,22 becomes a potential problem. .

  If the strips 16 and 22 are wound over a smaller angle, the length of the strips 16 and 22 may be shortened. This has the advantage that a shorter shank 14 and bore 19 are employed. However, if the lengths of the strips 16 and 22 are shortened, the strips 16 and 22 are subjected to a greater load per unit length and may therefore fail if subjected to excessive torque. Conversely, if the strips 16, 22 are wound over a greater angle, the strips 16, 22 will receive less load per unit length and can therefore transmit greater torque. In that case, however, a longer shank 14 and bore 19 are required.

  Thus, there is a balance to be taken between various parameters, such as lead angle, number of strips, strip winding angle, dock and bore length, drive assembly stop torque, dock and bore material. It is strength.

  The stirring device 3 can be detached from the cleaner head 1. This is achieved by removing the cap 8 that forms part of the housing 2. By removing the cap 8, a hole is formed in the side surface of the housing 2, and the stirring device 3 is removed from the hole. In order to remove the stirring device 3, the user needs to rotate the stirring device 3 with respect to the dock 12. This unscrews the stirrer 3 and separates the scissors device 3 from the dock 12, after which the user pulls the stirrer 3 out of the hole. When the stirrer 3 is attached to the cleaner head 1, the reverse operation is performed.

  The end of the strip 16 of the dock 12 is slightly tapered. This is useful when the user attaches the stirring device 3 to the dock 12. In particular, the end of the shank 14 is guided toward the center of the bore 19 by the chamfer 20.

  When attaching the agitator 3 to the dock 12, the two threads 15, 21 tend to be out of alignment. Each thread 15, 22 has four strips 16, 22. As a result, the user only needs to rotate the stirring device 3 over an angle of 90 degrees at most in order to align the two threads 15, 21. The user can easily rotate the stirring device 3 by 90 degrees while holding the stirring device 3. If a smaller number of strips 16, 22 are employed, the user will need to rotate the agitator 3 over a larger angle and the user will find this not easy.

  Each strip 16, 22 is wound over an angle of 180 degrees. As a result, in order to remove or install the stirring device 3, the user needs to rotate the stirring device 3 through 180 degrees. This is not so cumbersome and is generally achieved by slightly twisting the stirring device 3 once or twice. A smaller winding angle may be employed, in which case the user has the advantage that it only needs to rotate the stirring device 3 over a smaller angle. However, as described above, when the winding angle decreases, the length of the strips 16 and 22 decreases, and thus the strips 16 and 22 do. Receives a greater load per unit length. Therefore, a winding angle not smaller than 120 degrees is preferable. A winding angle larger than 180 degrees may be adopted for the strips 16 and 22. This has the advantage that the length of the strips 16, 22 is increased and thus can support a greater torque. However, when the lengths of the strips 16 and 22 are increased, the lengths of the shank 14 and the bore 19 are also increased. Furthermore, the user needs to rotate the stirring device 3 over a larger angle in order to remove or install the stirring device 3. A relatively short shank 14 and bore 19 should be maintained by employing a winding angle not greater than 360 degrees. In addition, the user can remove and attach the stirring device 3 with a smaller number of twists.

  Each thread 15, 21 has a sawtooth thread form, which has a relatively low friction characteristic, as noted earlier. As a result, the saw blade thread configuration, in addition to the advantages noted previously, facilitates the user to remove and install the agitator 3.

  The fit between the two threads 15, 21 may be relatively loose, in which case it further assists the user in removing and installing the stirring device 3. A relatively loose fit tends to cause a relatively large amount of play between the agitator 3 and the dock 12. However, since the stirring device 3 is screwed onto and fastened to the dock 12, even a relatively large amount of play is absorbed.

  In a conventional cleaner head having a removable stirring device, it is generally difficult to securely hold the stirring device in the axial direction within the cleaner head. The same applies to the cleaner head 1 of the present invention, and there is a certain amount of axial play between the agitator 3 and the dock 12 after the agitator 3 is mounted in the cleaner head 1. However, during operation of the cleaner head 1, the agitator 3 is screwed onto and fastened to the dock 12 to absorb any axial play. As a result, a removable stirring device 3 is provided which does not have the problems inherent in vibration and noise.

  In the embodiment described above, the thread 15 formed around the shank 14 is a male thread, and the thread 21 formed around the bore 19 is a female thread. As a modification, the thread 15 formed around the shank 14 may be a female thread, and the thread 21 formed around the bore 19 may be a male thread. Further, the dock 12 may have a bore 19 and a chamfered portion 20, and the stirring device 3 may have a tapered head 13 and a shank 14. Thus, in a more general sense, one of the stirring device 3 and the dock 12 has a tapered head 13, a shank 14 and a first thread 15, and the other of the stirring device 3 and the dock 12 is a bore. 19, a chamfer 20, and a second thread 21, which is complementary to the first thread 15.

  Each strip 16, 22 has a sawtooth thread form, but as a variant, other thread forms may be used. For example, both the square thread form and the trapezoidal thread form have relatively low frictional properties. However, the sawtooth thread form is generally relatively strong due to the relatively large base of each strip.

  The cleaner head shown in FIG. 1 is intended to form part of a vacuum cleaner. However, the agitator 3 and dock 12 may equally be employed in the cleaner head of other appliances such as floor cleaners or carpet cleaners. Further, although the drive assembly 4 of the above-described embodiment has the electric motor 4, the drive assembly 4 has a modified means for generating a torque necessary for driving the stirring device 3. It may be. For example, if the cleaner head 1 is intended to form part of a vacuum cleaner, the drive assembly 4 may have an air turbine driven by air drawn through the cleaner head 1. Good.

DESCRIPTION OF SYMBOLS 1 Vacuum cleaner head 3 Agitation apparatus 4 Drive assembly 12 Dock 13 Tapered head 14 Shank 15 Thread 16 Article 19 Bore 20 Chamfer 21 Thread

Claims (8)

A vacuum cleaner head,
A stirrer and a drive assembly for driving the stirrer;
The drive assembly has a dock for transmitting torque to the agitator;
One of the dock and the stirring device has a tapered head, a shank extending from the tapered head, and a thread formed around the shank, and the other of the dock and the stirring device is A bore including a chamfer, and complementary threads formed around the bore wall;
The shank protrudes into the bore, and the thread and the complementary thread are threaded when the stirrer is screwed to the dock and the tapered head is chamfered when the dock is rotated. Vacuum cleaner heads that mesh together to engage.   The cleaner head of claim 1, wherein the lead angle of each thread is not greater than 60 degrees.   The cleaner head according to claim 1 or 2, wherein the lead angle of each thread is not less than 40 degrees.   The vacuum cleaner head according to claim 1, wherein each screw thread has a plurality of strips.   5. A cleaner head according to claim 4, wherein each strip is wound at an angle not less than 120 degrees.   6. A cleaner head as claimed in claim 4 or 5, wherein each strip is wound at an angle not greater than 360 degrees.   7. A cleaner head as claimed in any one of the preceding claims, wherein each thread has a sawtooth thread form.   The stirrer is removable from the cleaner head, the rotation of the stirrer relative to the dock causes the screwing of the stirrer to be loosened, and the stirrer is separated from the dock. The cleaner head according to any one of? 7.

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