Patent Application
20080187394
1. Technical Field
The present invention relates to linear actuators and, more particularly, to a linear actuator with a ballscrew transmission system. The present invention provides a strategy aimed at improved operational efficiency and convenience of a quick-release device of such linear actuator.
2. Description of Related Art
The function principle of a linear actuator is that, in the main, a screw is rotated by a power source and in turn drives a nut screwed thereon to move a transmission part that carries a workpiece so that the workpiece can be linearly shifted. Such linear actuator can be extensively applied to beds, chairs, tables, vertical translation stages, power windows and so on. The velocity of the linear actuator is subject to the motor speed and the lead of the screw and therefore it takes time for the linear actuator to prepare for the movement of linear extension or contraction. However, the linear actuator is required to perform a quick contraction often and often. For instance, when the bed or chair where the linear actuator applied to is required to promptly return to an initial position thereof, the contracting flight of the linear actuator controlled by the motor and screw is generally inferior to expectation. For remedying this problem, a quick-release device has been equipped to the linear actuator.
One type of the prior quick-release devices related to the present invention implements a constraint spring to constrict the transmission part of the linear actuator so as to retain the transmission part and the nut from revolving relatively so that the object carried by the linear actuator can be secured from gravitating. Whereas, if the constraint spring is diametrically expanded to release the transmission part from constraint, the weight of the workpiece can bear on the transmission part and the nut to make the both promptly gravitate in a revolving motion so as to achieve the objectives of quick contraction of the linear actuator and prompt return of the workpiece. An example of such quick-release device may be U.S. Pat. No. 6,158,295.
A tool for fulfilling foresaid diametrical expansion of the constraint spring is typically a handle. As the appearance of a linear actuator is shown in
The collar 10 has a round-sectioned shape and the handle 15 has an opened annular assembling portion 16 that defines a round hole 17 therein for being mounted onto the out periphery of the collar 10. For securing the round hole 17 with respect to the collar 10, two screws 18 are arranged at the opening 16 to constricted the round hole 17 so that the round hole 17 and the collar 10 can be tightly combined in virtue of the friction between the round hole 17 and the collar 10. However, one problem with such a strategy is that the radically tightened screws 18 can induce plastic deformation of the handle 15 and in turn lead the handle 15 to break due to stress concentration. Another problem with such a strategy is that an auxiliary tool, such as a screwdriver, is required to tighten or loosen the screws 18 for adjusting the angle of the handle 15 and this is inconvenient to a user. One more problem with such a strategy is that the combining relationship between the round hole 17 and the collar 10 in virtue of the friction therebwtween is instable and the handle 15 may not easily and efficiently drive the collar 10 to rotate. Thus, the state that the handle 15 revolves in vain but the collar 10 stays still can frequently occur.
The present invention has been accomplished under these circumstances in view. It is the objective of the present invention to remedy the problem with the external control assembly for the quick-release device of a linear actuator.
To achieve these and other objectives of the present invention, the present invention implements a collar having a polygon-sectioned shaped out periphery and a handle comprising an assembling portion with an assembling hole shaped in a polygon-sectioned shape for being fittingly mounted onto the out periphery of the collar. Lying on said structure, a reinforcement rib is further arranged on the assembling portion, and a retaining recess and retaining rib are provided.
The foresaid resolution according to the present invention achieves a combined motion of simultaneous rotation about the axis of the collar of the handle and the collar so that the handle can easily and efficiently drive the collar to rotate.
The foresaid resolution according to the present invention allows a user to handily, easily and promptly assemble the handle and collar with his bare hands.
The invention as well as a preferred mode of use, further objectives and advantages thereof, will best be understood by reference to the following detailed description of an illustrative embodiment when read in conjunction with the accompanying drawings, wherein:
In
The purpose of rotating the collar 30, just alike that of the prior arts, is to diametrically expand a constraint spring positioned in the collar 30 to release the transmission part of the linear actuator from constraint so that the weight of the workpiece can bear on the transmission part and the nut to make the both promptly gravitate in a revolving motion so as to achieve the objectives of quick contraction of the linear actuator and prompt return of the workpiece
Again, according to
To sum up, the advantages of the structure of the disclosed subject matter includes that the collar 30 provides the regular-polygon-shaped out periphery 31 and the handle 40 provides matching regular-polygon-shaped assembling hole 43 so that when the both are assembled, as the combined motion of simultaneous rotation about the axis of the collar 30 thereof is achieved, the handle 40 can easily and efficiently drive the collar 30 to rotate. Moreover, the disclosed handle 40 is formed in an integral piece and has the reinforcement rib 44 that facilitates enhancing structural strength. The mutual retaining relation between the retaining rib 32 and the retaining recess 45 helps to prevent the handle 40 from slipping away from the collar 30 along the direction parallel to the axis of the collar 30. Thereby, without the need of any screw component, the secure assembly of the handle and collar can be accomplished.
The advantage of the disclosed subject matter in use is that a user can simply mount the handle 40 onto the collar 30 with the assembling hole 43. Thus, the assembly can be handily, easily, and promptly assembled with the user's bare hand without the need of other tools. By this advantage, the user can conduct repeated experimental assembling operations to determine the optimum extending direction of gripping portion 42 of the handle 40 conforming to the surrounding environment that facilitates the user's operating the gripping portion.
Although a particular embodiment of the invention has been described in detail for purposes of illustration, it will be understood by one of ordinary skill in the art that numerous variations will be possible to the disclosed embodiments without going outside the scope of the invention as disclosed in the claims.
