Patent Application
20140251055
1. Technical Field
The present disclosure generally relates to robots, particularly to a robotic arm for a robot.
2. Description of Related Art
Robots have replaced humans in performing repetitive and dangerous tasks, especially those in extreme environments or are unable to be done by humans do due to size limitations. Robots include several arms that are connected to each other by riveting, such that each of the arms is capable of moving relative to each other. However, the robots assembled in such manner are not always facile enough.
Therefore, there is room for improvement within the art.
Many aspects of the disclosure can be better understood with reference to the drawings. The components in the drawings are not necessarily drawn to scale, the emphasis instead being placed upon clearly illustrating the principles of the disclosure. Moreover, in the drawings, like reference numerals designate corresponding parts throughout the views.
The driving unit 10 includes a motor 12, a decelerator 14, and a shaft 16. The motor 12 drives the shaft 16 to rotate. The decelerator 14 decelerates and controls the shaft 16 to rotate at a desired speed slower than a speed of the motor 12. A shaft bushing 161 is coiled around and fixed to an end of the shaft 16. The shaft bushing 161 defines a plurality of threaded holes 165 in an end surface.
The first arm assembly 20 includes a rotating block 22, a fastening member 24, and a connecting member 26. The rotating block 22 is secured to the shaft 16 to be rotated by the shaft 16. In the exemplary embodiment, the rotating block 22 has a substantially rod shape. An end of the rotating block 22 defines a mounting hole 220. An opposite end of the rotating block 22 defines a notch 222. The shaft 16 and the shaft bushing 161 are inserted into the mounting hole 220. The fastening member 24 includes an annular plate 240 and a plurality of screws 242 threadedly secured to the annular plate 240. The annular plate 240 longitudinally defines a center hole 244. The annular plate 240 has an external diameter larger an internal diameter of the mounting hole 220. The annular plate 240 covers the mounting hole 220. As such, the shaft 16 is inserted through the center hole 244, and the screws 242 are inserted into the mounting hole 220 and are screwed into the threaded holes 165 of the shaft bushing 161, thereby fastening the rotating block 22 to the shaft 16 and enabling the rotating block 22 to be rotated by the shaft 16.
The connecting member 26 includes a post 260 and two balls 262 secured to two opposite ends of the posts 260. A substantially middle portion of the post 260 is secured in the notch 222 of the rotating block 22, thereby fixing the post 260 to the rotating block 22. When the rotating block 22 moves, the rotating block 22 drives the post 260 to move.
The second arm assembly 30 includes two arms 32 rotatably attached to the two balls 262, two intermediate members 34, and two elastic members 36.
In the exemplary embodiment, each arm 32 has a substantially bar shape. An end of each arm 32 defines a mounting recess 320 for receiving and securing one of the intermediate members 34. An opposite end of each arm 32 away from the mounting recess 320 may be connected to an operating mechanism (not shown) for holding or griping work-pieces. In the exemplary embodiment, each mounting recess 320 is substantially cylindrical. Each intermediate member 34 is substantially cylindrical. Each intermediate member 34 defines a receiving recess 340 in an end and defines a hole 342 in an opposite end. Each hole 342 communicates with the corresponding receiving recess 340. Each receiving recess 340 has a spherical inner circumferential surface 344 to be engaged with one of the balls 262. In this exemplary embodiment, each intermediate member 34 is made of copper. Each intermediate member 34 is received and secured in one of the mounting recesses 320, and each ball 262 is partially received in one of the receiving recesses 340 of the intermediate members 34 with an end portion extending into the corresponding hole 342 (best shown in
Each elastic member 36 can be an extension spring. The elastic members 36 are positioned between the two arms 32, and ends of each elastic member 36 are attached to the arms 32 to create an elasticity to force the spherical inner circumferential surfaces 344 of the intermediate members 34 to tightly abut against the balls 262, thereby assembling the arms 32 and the connecting member 26 together. The balls 262 are capable of rotating in the receiving recesses 340. As such, the arms 32 are capable of rotating about the balls 262. In this exemplary embodiment, two fixing members 324 are fixed on the arms 32, and ends of the elastic members 36 are attached to the fixing members 324. In other embodiments, the number of the elastic members can be one or more than two.
To assemble the robotic arm 100, the shaft 16 and the shaft bushing 161 are inserted into the mounting hole 220 of the rotating block 22. The screws 242 on the fastening member 24 are screwed into the threaded holes 165 of the shaft bushing 161 through the mounting hole 220, thereby fastening the rotating block 22 to the shaft 16 and enabling the rotating block 22 to be rotated by the shaft 16. Then, a substantially middle portion of the post 260 is secured in the notch 222 of the rotating block 22. The two intermediate members 34 are secured in the mounting recesses 320 of the two arms 32. The two balls 262 are aligned with the receiving recesses 340. The elastic members 36 are then connected to the two arms 32, enabling the spherical inner circumferential surfaces 344 of the intermediate members 34 to tightly abut against the balls 262, thereby assembling the arms 32 and the connecting member 26 together.
In use, the driving unit 10 drives the first arm assembly 20 to rotate about a shaft 16. When the balls 262 move relative to the intermediate members 34, a frictional force is created between the balls 262 and the intermediate members 34. The frictional force forces the arms 32 of the second arm assembly 30 to move with the balls 262. That is, the friction force forces the arms 32 to rotate about the shaft 16. At the same time, the arms 32 rotate about the balls 262, enlarging a moving sphere of the robotic arm 100. The elastic members 36 enable the intermediate members 34 to always abut against the balls 262 during a motion.
It is understood that the two balls 262 may be other universal joints to make the two arms 32 move with the rotating block 26 and simultaneously rotate about the universal joint.
It is to be understood, however, that even through numerous characteristics and advantages of the present disclosure have been set forth in the foregoing description, together with details of assembly and function, the disclosure is illustrative only, and changes may be made in detail, especially in the matters of shape, size, and arrangement of parts within the principles of the disclosure to the full extent indicated by the broad general meaning of the terms in which the appended claims are expressed.
| Number | Date | Country | Kind |
|---|---|---|---|
| 2013100691185 | Mar 2013 | CN | national |
