Gear drive system with adjusting structure

A gear drive system includes a securing panel, a first slave gear, a drive gear, and an adjusting structure. The securing panel includes a panel body, a rack, and a rotating shaft. An upper part of the first slave gear is adjacent to the rack and aligned with the rack. The drive gear engages the first slave gear. The adjusting structure includes an elastic element, a slave element pivotally mounted to the panel body, and a third slave gear. The third slave gear defines a rotating hole. The rotating shaft is received in the rotating hole. The second slave gear is movable related to the panel body to enable the rotating shaft to be located in different positions of the rotating hole. The third slave gear is driven to move and rotate. The slave element is driven to rotate to press the elastic element.

BACKGROUND

1. Technical Field

The present disclosure relates to gear drive systems, particularly to a gear drive system with an adjusting structure.

2. Description of Related Art

A traditional scanner includes a gear drive system. The gear drive system includes a drive gear, a first slave gear, a rack, and a second slave gear. The first slave gear is aligned with the rack. The drive gear is rotated by a motor to move the first slave gear along the rack. The slave gear engages the third slave gear to stop rotation during the process. When the drive gear rotates to engage the slave gear, the drive gear may be blocked from rotating when the teeth pitches of the rack and the slave gear do not match with each other.

Therefore, there is room for improvement within the art.

DETAILED DESCRIPTION

FIG. 1shows a gear drive system in accordance with one embodiment. The gear drive system includes a securing panel10, a drive gear20, a first slave gear30, a second slave gear50, and an adjusting structure60.

The securing panel10includes a panel body11, a rack13, a receiving portion15, a pivot shaft17, and a rotating shaft19. The rack13, the receiving portion15, the pivot shaft17, and the rotating shaft19extend from the panel body11. The receiving portion15, the pivot shaft17, and the rotating shaft19are below the rack13(shown inFIG. 3). The receiving portion15defines a receiving space151and a cutout153, and the cutout153communicates with the receiving space151. The cross section of the rotating shaft19is substantially eye-shaped. The rack13comprises a row of associating teeth131for engage the drive gear20.

The adjusting structure60includes an elastic element61received in the receiving space151, a slave element63, and a third slave gear65. The slave element63includes a pivot body631, a pressing arm633extending from the pivot body631, and an engaging arm635extending from the pivot body631. The pivot body631defines a pivot hole6311corresponding to the pivot shaft17. The engaging arm635defines a plurality of engaging teeth6351for engaging the third slave gear65. The pressing arm633is used for being received in the receiving space151via the cutout153to resist the elastic element61. In one embodiment, the elastic element61is a spring. The third slave gear65defines a rotating hole651. The rotating hole651is circular. The rotating hole651is used for receiving the rotating shaft19, and when the third slave gear65is moved along the panel body11, the rotating shaft is moved in the rotating hole651relative to the third slave gear65(seeFIGS. 3-5).

The first slave gear30includes a first gear portion31and a second gear portion33. The first gear portion31and the second gear portion33are coaxial. The second gear portion33engages the second slave gear50. The first slave gear30and the second slave gear50are both pivotally mounted to the panel body11. The upper portion of the first gear portion31is aligned with the rack13.

FIGS. 2 and 3show that in assembly, the elastic element61is placed in the receiving space151of the receiving portion15. The pivot shaft17is received in the pivot hole6311of the slave element63and the pressing arm633is received in the receiving space151via the cutout153to contact the elastic element61. The rotating shaft19is received in the rotating hole651of the third slave gear65to engage the third slave gear65with the second slave gear50and the engaging teeth6351of the slave element63. The rotating shaft19is located in the lower part of the rotating hole651due to the support of the engaging arm635. The drive gear20engages the first gear portion31of the first slave gear30.

FIG. 4shows that in use, a motor (not shown) rotates the drive gear20along a counterclockwise direction. The first slave gear30creates a force along the clockwise direction to be applied to the third slave gear65. The third slave gear65is driven by the force to move down and rotate, thereby driving the first slave gear30to rotate. At this time, the slave element63is driven by the third slave gear65to rotate along a clockwise direction and the rotating shaft19is located in the upper part of the rotating hole651. Thereby the pressing arm633presses the elastic element61. Thus, the drive gear20can easily rotate from the first slave gear30to the rack13due to the rotation of the first slave gear30, no matter whether the teeth pitches of the first slave gear30and the rack13matches with each other.

FIG. 5shows that when the drive gear20rotates to engage the rack13, the elastic element61rebounds to drive the third slave gear65to move up and rotate along a counterclockwise direction, thereby the third slave gear65moves back to the original position.

In one embodiment, the third slave gear65engages the first slave gear30directly. The second slave gear50is not needed. The engaging arm635of the adjusting structure60is located above the third slave gear65.