IPC분류정보
국가/구분 |
United States(US) Patent
등록
|
국제특허분류(IPC7판) |
|
출원번호 |
US-0140561
(2013-12-26)
|
등록번호 |
US-8979098
(2015-03-17)
|
발명자
/ 주소 |
- Wang, Wen-Fa
- Deng, Jian-Wen
- Chen, Jia-Chao
|
출원인 / 주소 |
|
인용정보 |
피인용 횟수 :
5 인용 특허 :
12 |
초록
▼
A foldable platform truck includes a platform, two wheel-connecting bars rotatably attached to the platform, a handle assembly, a handle release and locking mechanism for controlling the handle assembly, a pair of first gear members and a pair of second gear members. The handle release and locking m
A foldable platform truck includes a platform, two wheel-connecting bars rotatably attached to the platform, a handle assembly, a handle release and locking mechanism for controlling the handle assembly, a pair of first gear members and a pair of second gear members. The handle release and locking mechanism has an actuator to be operated to allow the handle assembly to pivot between an upright position and a horizontal position. When the handle assembly is in the horizontal position, the wheels are folded up underneath the platform and lie horizontally with respect thereto. And, when the handle assembly is pulled away from the platform to the upright position, the first gear members engage and turn the second gear members, resulting in the wheel-connecting bars rotating to fold out the wheels from underneath the platform toward an eventual perpendicular position with respect to the underside of the platform.
대표청구항
▼
1. A collapsible platform truck comprising: a platform;a pair of wheel-connecting bars rotatably attached to a bottom of the platform;a plurality of wheels connected to the wheel-connecting bars;a handle assembly having a pair of lower vertical frame members, a pair of handle arms telescopically att
1. A collapsible platform truck comprising: a platform;a pair of wheel-connecting bars rotatably attached to a bottom of the platform;a plurality of wheels connected to the wheel-connecting bars;a handle assembly having a pair of lower vertical frame members, a pair of handle arms telescopically attached in the vertical frame members, and a central grip joining the handle arms;two respective pivot pins;a pair of pivot brackets each having one end secured to a respective one of the vertical frame members, and the other end pivotally connected to a respective one of the wheel-connecting bars by means of a respective one of the pivot pins;a handle release and locking mechanism disposed in the handle assembly and having an actuator configured to be operated to allow the handle arms together with the central grip to displace with respect to the vertical frame members among a first extended locking position, a second retracted locking position, and a third retracted unlocking position where the handle assembly is unlocked and allowed to pivot between a generally upright position and a generally horizontal position generally flush with a top surface of the platform;a pair of first gear members connected to the handle assembly; anda pair of second gear members meshing with the first gear members and connected to the wheel-connecting bars;wherein when the handle assembly is in the horizontal position, the wheels are folded up underneath the platform and lie horizontally with respect thereto; and when the handle assembly is pulled away from the platform to the upright position, the first gear members engage and turn the second gear members, resulting in the wheel-connecting bars rotating to fold out the wheels from underneath the platform toward an eventual perpendicular position with respect to the underside of the platform; andwherein each of the wheel-connecting bars includes an outer tube and an inner tube inserted in a front end of the outer tube; the outer tube defines at its front end a pair of opposed arc-shaped slots in a periphery thereof; the inner tube defines a pair of opposed pivot bores in a periphery thereof; and each of the pivot pins is secured on the respective pivot bracket and passes through the opposed arc-shaped slots of the outer tube and the opposed pivot bores of the inner tube in such a manner that the outer tube is rotatable in a range of about 90 degrees with respect to the inner tube. 2. The collapsible platform truck of claim 1, wherein the handle assembly further has at least one horizontal frame member supporting the vertical frame members; and the actuator is disposed in the middle of the horizontal frame member and is configured to be depressed towards a position that is substantially contiguous with a surface of the horizontal frame member, which unlocks the handle arms so that the handle arms are allowed to be moved among the first extended locking position, the second retracted locking position and the third retracted unlocking position, and upon release, the actuator is restored back to its original position and locks the handle arms in either the first extended locking position or the second retracted locking position. 3. The collapsible platform truck of claim 1, wherein the first gear members are mounted to outer sides of pivot brackets by the pivot pins respectively; and the second gear members are mounted around the respective front ends of the outer tubes of the wheel-connecting bars. 4. The collapsible platform truck of claim 1, further comprising two self-locking mechanisms each including a limiting bolt traversely passing across a front end of the inner tube, a substantially U-shaped locking bracket disposed in the pivot bracket and underneath the respective vertical frame member, a driving tube seated in the locking bracket; wherein when the handle arms of the handle assembly are in the second retracted locking position, the locking bracket engages with the limiting bolt to stop the handle assembly from pivoting; and when the handle arms move from the second retracted locking position to the third retracted unlocking position, the driving tube drives the locking bracket to disengage with the limiting bolt so as to allow the handle assembly to pivot between the upright position and the horizontal position. 5. The collapsible platform truck of claim 4, wherein the driving tube is formed with a pair of studs on opposite sides thereof; the substantially U-shaped locking bracket has a pair of confining notches for reception of opposite ends of the limiting bolt and a pair of inclined slots for accommodating the studs of the driving tube such that vertical movement of the driving tube causes the locking bracket to move horizontally. 6. The collapsible platform truck of claim 4, wherein each of the pivot brackets has a pair of parallel mounting plates that define opposed pivot holes respectively for accommodating the pivot pin as well as opposed arc-shaped slots for insertion of the limiting bolt. 7. The collapsible platform truck of claim 4, wherein the handle assembly further includes a pair of guiding rods each disposed in the respective vertical frame member; the pivot bracket is joined to a lower end of the respective guiding rod; the driving tube is mounted around the guiding rod; and each of the handle arm is hollow and slidably mounted around the guiding rod to push the driving tube in order to have the locking bracket disengaged from the limiting bolt. 8. The collapsible platform truck of claim 4, wherein each of the self-locking mechanisms further includes a coil spring mounted around the driving tube to be pressed by the respective handle arm as the handle arm is in the third retracted unlocking position; and when the coil spring is released from the handle arm, the driving tube is drawn back to its original position by the coil spring to have the locking bracket rejoin with the limiting bolt. 9. The collapsible platform truck of claim 8, further comprising at least two connecting bolts each for connecting the vertical frame member of the handle assembly, the driving tube and the pivot bracket, wherein the driving tube is formed with a protrusion on a side; the driving tube defines a pair of opposed axial elongated slots for insertion of the connecting bolt; and the coil spring is interposed between the protrusion and the connecting bolt. 10. The collapsible platform truck of claim 8, wherein the platform defines in its top surface a generally U-shaped depression for accommodation of the handle assembly.
※ AI-Helper는 부적절한 답변을 할 수 있습니다.