Lifting device for headrest

A lifting device for headrest includes a fixing frame, a driving rod, two headrest supports, a driving device fixed on the fixing frame, and two lifting mechanisms configured on the fixing frame and located at two sides of the driving device. Each lifting device includes a reversing driving assembly, a guide rod and a slider moveably connected on the guide rod, the two headrest supports are mounted on the sliders, respectively, the driving rod passes through and is driven by the driving device, two ends of the driving rod are connected with the reversing driving assemblies, respectively, and the slider is driven by the reversing driving assembly. Both sliders on the two lifting mechanisms have driving forces so as to improve balance at both sides and make the support force stronger. The headrest is kept in a stable status, thereby preventing damage of the lifting device and the sofa.

RELATED APPLICATIONS

This application claims the benefit of priority to Chinese Patent Application No. 201810843690.5 filed in Jul. 27, 2018, which is hereby incorporated by reference in its entirety.

FIELD OF THE INVENTION

The present invention relates to a field of furniture parts, more particularly to a lifting device for a sofa headrest.

BACKGROUND OF THE INVENTION

Chinese Utility Model Application No. 201420867174.3 discloses a headrest adjusting support which includes two linkage assemblies and a linear driving device located between the linkage assemblies. An output end of the linear driving device is connected with the linkage assemblies via a driving rod, so that a fastener of the linkage assembly is driven to rotate by means of linear reciprocating motion, thereby the height and the angle of the headrest can be adjusted.

However, the headrest adjusting support has some drawbacks. For example, the linear driving device is located in the middle, the linkage assemblies at both sides are driven only by the driving rod, thus the balance of the support is poor, and the support force is not strong. In actual operation, since the width of the headrest is big, and sitting position of user is not fixed, thus loading forces at two sides of the headrest are different, which causes one linkage assembly endure a larger loading force, while the other linkage assembly endure a smaller loading force. Furthermore, the driving rod at the middle cannot balance them, as a result, the movement ranges of both linkage assemblies are different, which causes the headrest deflect, even generates damages on the sofa structure.

Thus it's necessary to provide an improved lifting device for headrest which has better balance.

SUMMARY OF THE INVENTION

One objective of the present invention is to provide a lifting device for a headrest which has improved balance.

To achieve the above objective, a lifting device for headrest of the present invention includes a fixing frame, a driving rod, two headrest supports, a driving device fixed on the fixing frame, and two lifting mechanisms configured on the fixing frame and located at two sides of the driving device. Each lifting device comprises a reversing driving assembly, a guide rod and a slider moveably connected on the guide rod, the two headrest supports are mounted on the sliders, respectively, the driving rod passes through the driving device and is driven by the driving device, two ends of the driving rod are connected with the reversing driving assemblies, respectively, and the slider is driven by the reversing driving assembly to slide on the guide rod.

In comparison with the prior art, since the lifting mechanisms are configured at two sides of the driving device, the driving rod driven by the driving device is connected with the reversing driving assembly, and the slider installed with the headrest support is movably connected on the guide rod, thus the driving force from the driving device can be transferred to the reversing driving assembly by means of the driving rod, causing the slider to slide up and down along the guide rod. Differing from the prior art that uses a driving rod to actuate two linkage assemblies, the lifting device for headrest in the present invention uses the driving rod and the reversing driving assembly to transfer the driving force from the middle driving device to the two lifting mechanisms, so that both sliders on the two lifting mechanisms have driving forces to improve balance at both sides and make the support force stronger. Particularly, the two sliders at both sides can maintain the same movement even if the loading forces at both sides of the headrest are different, that is, the headrest is kept in a stable status, thereby preventing damage of the lifting device and the sofa.

Preferably, the driving device comprises an electric motor and a gear box, and the driving rod passes through the gear box and is connected with the gear box.

Preferably, a cross section of the driving rod is polygonal.

Preferably, the lifting mechanism further comprises a shell fixed on the fixing frame, the guide rod is fixed on the shell, the reversing driving assembly is configured in the shell and the guide rod, and an end of the driving rod is inserted into the shell

Preferably, the reversing driving assembly comprises a screw rod positioned in the guide rod and a gear group connected between the driving rod and the screw rod, and the slider is connected with the screw rod.

Preferably, the gear group comprises two conical gears engaging with each other, and the two conical gears are fixed to the driving rod and the screw rod respectively.

Preferably, an inserting slot is provided on the slider, by which a lower end of the headrest support is detachably inserted into the inserting slot.

Preferably, a ring groove is provided on the lower end of the headrest support, and a spring is provided at the slider and received in the ring groove.

Preferably, the lifting device further includes two guide screw bushings configured at two ends of the fixing frame respectively, and the two headrest supports passes through the two guide screw bushings.

Preferably, a headrest hinge is fixed on the headrest support, and the headrest hinge comprises a fixing part connected with the headrest support and a swinging arm connected with the fixing part.

DETAILED DESCRIPTION OF ILLUSTRATED EMBODIMENTS

F or further understanding the features, technical solutions, purposes and functions of the present invention, and explaining the advantages and spirits of the invention, detailed descriptions for embodiments follow.

As shown inFIG. 1, a lifting device for headrest according to the present invention is installed within a sofa body to connect with a sofa headrest, thereby adjusting the height of the headrest. The lifting device for headrest includes a fixing frame1, a driving device2, a driving rod3, two headrest supports4, and two lifting mechanisms5.

Specifically, the fixing frame1is the structure basis of the whole lifting device. In this embodiment, the fixing frame1is a rectangular frame. The driving device2is an actuator of the lifting device for headrest, which is fixed on the middle position of the fixing frame1. The two lifting mechanisms5are connected at two ends of the fixing frame1, namely located at two sides of the driving device2. The driving rod3has a non-circular cross section, and the driving rod3passes through the driving device2and is driven by the driving device2; two ends of the driving rod3are connected with the two lifting devices5respectively, so that the driving force from the driving device2can be transferred to the lifting mechanisms5. Each lifting mechanism5includes a shell51fixed on the fixing frame1, a guide rod52fixed on the shell51, a slider53moveably connected on the guide rod52, and a reversing driving assembly configured in the shell51and the guide rod52and connected with the slider53. Specifically, the end of the driving rod3is connected with the reversing driving assembly, thus when the driving rod3rotates, the slider53will be driven to slide on the guide rod52by means of the reversing driving assembly. The two headrest supports4are mounted on the two sliders53respectively, and a headrest is mounted on the headrest supports4, when the slider53moves up and down, the height and position of the headrest can be adjusted.

Referring toFIG. 2, the driving device2includes an electric motor21and a gear box22. Specifically, driving force outputted from the electric motor21is transferred to the gear box22through which the driving rod3passes. For example, the driving rod3is fixed to a gear of the gear box22, by which the driving rod3is driven by the gear box22. Preferably, the driving rod3has a polygonal cross section, for example is a hexagonal cross section in this embodiment. Specifically, the driving device2further includes two housing parts23connected together to shield the electric motor21and the gear box22, so as to protect the electric motor21and the gear box22. Optionally, the driving device2can be other actuating devices besides the electric motor21and gear box22, so as to drive the driving rod3.

As illustrated inFIGS. 3 to 5, the reversing driving assembly includes a screw rod54positioned in the guide rod52and a gear group located in the shell51, the screw rod54and the slider53are in a threaded connection. When the screw rod54is rotated, the slider53slides downwards; the gear group is connected between the driving rod3and the screw rod54, so that the rotation of the driving rod3can be transferred to the screw rod54. In this embodiment, the gear group includes two conical gears55,56which are respectively fixed on the ends of the driving rod3and the screw rod54. In such a way, driving force transfer can be achieved between the driving rod3and the screw rod54that are substantially perpendicular with each other. Optionally, the gear group can has other gears, and the amount of the gear is not limited. The reversing driving assembly can use other structures such as worms and gears to achieve the driving force transfer between the driving rod3and the screw rod54.

Specifically, the guide rod52is a hollow structure, and the screw rod54is located in the guide rod52and extended along a direction parallel to the guide rod52. Specifically, a long gap521parallel to the screw rod54is formed on a side wall of the guide rod52. The slider53defines a cavity and has a receiving part531formed in the cavity, a connecting part532is connected between the receiving part531and the side wall of the cavity. Further, a screw hole533is formed on the receiving part531to match with the screw rod54. Specifically, the slider53is movably connected on the guide rod52, meanwhile the receiving part531is connected with the screw rod54so that the screw hole533and the screw rod54are in screw connection; additionally, the connecting part532is received in the long gap521and moves along the long gap521. When the screw rod54rotates, the slider53can move up and down along the guide rod52by means of the screw connection of the screw rod54and the screw hole533.

Referring toFIG. 6, an inserting slot536is provided on the slider53, by which the lower end of the headrest support4is detachably inserted into the inserting slot536. In actual installation, firstly the headrest supports4are fixed to the headrest, then the headrest supports4are inserted into the inserting slots536of the sliders53, so that the headrest can be mounted on the lifting device for headrest of the present invention. Further, the slider53is provided with a spring58encircling the inserting slot536, specifically, a curved arm of the spring58is positioned outside the inserting slot536, while a straight arm of the spring58is across the inserting slot536. Accordingly, a ring groove41is provided on the lower end of the headrest support4, when the headrest support4is inserted into the inserting slot536, the straight arm of the spring58is received into the ring groove41, so that the connection between the headrest support4and the inserting slot536is more steady.

Optionally, the headrest can be mounted on the headrest supports4directly, but in this situation, only the height of the headrest, instead of the angle of the headrest can be adjusted. Therefore, in a preferable embodiment, a headrest hinge6is provided at the headrest support4. Specifically, the headrest hinge6includes a fixing part61connected with the headrest support4and a swinging arm62connected with the fixing part61. More specifically, the swinging arm62can be rotated or locked relatively to the fixing part61, and the headrest is fixed on the swinging arm62. In such a configuration of the headrest hinge6, the angle of the headrest can be adjusted. Since the headrest hinge6is a common component, and its detailed structure is omitted here.

Referring toFIG. 7, the lifting device further includes two guide screw bushings7configured at two ends of the fixing frame1respectively. In actual installation, the fixing frame1is firstly fixed in the sofa body, and the two guide screw bushings7are screwed to press against the top plate8of the sofa frame, specifically, the guide screw bushing7is located right above the inserting slot536of the slider53. And then, the headrest9is fixed on the headrest hinges6, the two headrest supports4pass through the guide screw bushings7to insert into the inserting slots536, in such a way, the installation is completed. During the sliding of the slider53and the headrest supports4, the guide screw bushings7play a role of guiding, so that the movement of the headrest9can be more stable.

In the present invention, since the lifting mechanisms5are configured at two sides of the driving device2, the driving rod3driven by the driving device2is connected with the reversing driving assembly, and the slider53installed with the headrest support4is movably connected on the guide rod52, thus the driving force from the driving device2can be transferred to the reversing driving assembly by means of the driving rod3, causing the slider53to slide up and down along the guide rod52. Differing from the prior art that uses a driving rod to actuate two linkage assemblies, the lifting device for headrest in the present invention uses the driving rod3and the reversing driving assembly to transfer the driving force from the middle driving device2to the two lifting mechanisms5, so that both sliders53on the two lifting mechanisms5can driving forces to improve the balance at both sides and make the support force stronger. Particularly, the two sliders53at two sides can maintain the same movement even if the loading forces at two sides of the headrest are different, that is, the headrest is kept in a stable status, thereby preventing damage of the lifting device and the sofa.