Apparatus of a collapsible handcart for turning a platform when operating a retractable handle

A collapsible handcart. The handcart includes two wheel seats, a retractable handle, two wheels and a platform. The wheels are pivoted on the wheel seats respectively for free rotation and the retractable handle is mounted to the wheel seats. The platform is pivoted on the wheel seats for movement between an extended position, at which the platform is turned downwards, and at a collapsed position, the platform is turned upwards. The platform can be driven to turn to the collapsed position when the retractable handle is retracted and the platform also can be driven to turn to the extended position when the retractable handle is extended.

FIELD OF THE INVENTION

The present invention relates to a handcart, and more particularly to an apparatus of a collapsible handcart for turning a platform when operating a retractable handle.

BACKGROUND OF THE INVENTION

U.S. Pat. No. 4,917,392 taught a collapsible handcart, which provided an S-shaped cam slot at each of wheel seats, so that user can turn a platform to drive wheels to turn. Such that, the conventional handcart can be turn to an extended position, at which the platform was turned downwards and the wheels were driven to turn parallel to each other, and a collapsed position, at which the platform was turned upwards and the wheels were turned 90 degrees. When the handcart was turned to the extended position, the handcart can carry goods on the platform and can be driven to run, and when the handcart was turned to the collapsed position, the handcart will have a smaller size to be stored or carried.

In fact, there will be two steps for a user to change the conventional handcart from the collapsed position to an operating mode. First, user had to turn the platform downwards, and then he/she had to extend a retractable handle to pull the handcart to run. If user wanted to collapse the handcart, there still were two steps. In addition, user usually had to bend his/her trunk to reach the platform for turning it.

SUMMARY OF THE INVENTION

The primary objective of the present invention is to provide a collapsible handcart, which has a new operating mode to extend and to collapse the handcart.

According to the objective of the present invention, a collapsible handcart comprises two wheel seats, a retractable handle, two wheels and a platform. The wheels are pivoted on the wheel seats respectively for free rotation and the retractable handle is mount to the wheel seats. The platform is pivoted on the wheel seats for movement between an extended position, at which the platform is turned downwards, and a collapsed position, at which the platform is turned upwards. The platform can be driven to turn to the collapsed position when the retractable handle is retracted and the platform also can be driven to turn to the extended position when the retractable handle is extended.

DETAIL DESCRIPTION OF THE INVENTION

Please refer toFIGS. 1-3, wherein a collapsible handcart1of the first preferred embodiment of the present invention mainly comprises two wheel seats10, a retractable handle20, a platform30and two wheels40.

Each of the wheel seats10has a slot11at a topside thereof to receive the retractable handle20and a chamber12at an exterior side thereof in communication with the slot11. Each of the wheel seats10has a hole (not shown) at the bottom side of the chamber12running through the wheel seat10. The wheel seat10further has a bearing surface (not shown) at rear side thereof.

The retractable handle20has two sets of retractable tubes, a handle bar23and a control bar24. Each set of the retractable tubes includes a first tube21and a second tube22slidably engaged with each other. The handle bar23coupled with the second tubes22at the distal ends thereof and the control bar is coupled with the first tubes21. The first tubes21receive their bottom ends in the slots11of the wheel seats10respectively and are fixed therein. The first tubes21are provided with openings211communicated with the chambers12of the wheel seats10respectively. The control bar24has a mechanism (not shown) therein to operate control devices (not shown) installed in the second tubes22such that the retractable tubes21and22can be retracted as shown in FIG.1and can be extended as shown in FIG.2. The retractable handle20is a conventional element and reader can find the detail structure in many relative inventions, so I will not describe the detail here.

The platform30is fixed with a shaft31at its rear side thereof. The opposite ends of the shaft31run through the holes of the wheel seats10respectively to pivot the platform30on the wheel seats10. Such that the platform30can be turned between a collapsed position as shown in FIG.1and an extended position as shown in FIG.2.

The opposite ends of the shaft31are located in the chambers12of the wheel seats10on which pivot the wheels40for free rotation. The shaft31has two flat surfaces32at each of the opposite sides thereof which are located in the chambers12of the wheel seats10respectively.

Two sets of transferring means50are installed in the chambers12of the wheel seats10respectively. The transferring means50are to drive the platform30to turn to the collapsed position when the retractable tubes11and12are retracted and to drive the platform30to turn to the extended position when the retractable tubes11and12are extended.

The transferring means50has a housing51, a trigger device56, a driven device57, a first spring58and a second spring59.

The housing51is a combination of a first piece511and a second piece512, wherein the first piece511has a transverse guiding rail52at its interior side and the second piece512has an extended board53at a side thereof. The second piece512attaches its exterior side onto the bottom of the chamber12for the board53attached on the first tube11. The second piece512is provided with an opening54corresponding to the opening211of the first tube11. The first piece511is attached on to the second piece512by means of two screws55running through the first piece511and the second piece512and screwing into the wheel seat10to secure the housing51in the chamber12. The first piece511and the second piece512are provided with shaft openings513for the shaft31running through the housing51. The first piece511and second piece512are each provided with two bearing arms514and515that rest against the first tube11. The housing51has an extended board516at a side thereof attached on the first tube21, as illustrated inFIGS. 3 and 4.

Please refer toFIG. 4, The trigger device56has an inclined surface561at an end thereof, a driving surface562at interior side thereof, a first hole563and a second hole564. The first and the second hole563and564are arranged in horizontal direction and the first hole563closes to the inclined surface561. The first and the second hole563and564are communicated with each other and two converting portions565are provided in connected with the first and the second hole563and564. The trigger device56further has two flat surfaces566at the opposite side walls of the second hole564.

The trigger device56is movably engaged with the guiding rail52in the housing51with the inclined surface561extended into the first tube11via the openings54and211of the housing51and the first tube11. The first spring58exerts the rear end of the trigger device56to provide an initial position wherein the inclined surface561is received in the first tube11. The trigger device56can be driven for displacement between a first position (FIG. 6) and a second position (FIG.7).

Please refer to FIG.4. The driven device57also has a driving surface572, a first hole573, a second hole574, two converting portions575and two flat surfaces576similar to the trigger device56has. The first hole573and the second hole574are arranged in vertical direction and the second hole574located at upper. The second spring59exerts the top end of the driven device57.

The driven device57is received in the housing51with the driving surface572thereof engaged with the driving surface562of the trigger device56such that the movement of the trigger device56will drive the driven device57for displacement between a first position (FIG. 6) and a second position (FIG.7). The moving direction of the driven device57is substantially perpendicular to the moving direction of the trigger device56.

I only describe the detail of one set of the transferring means50, the other one has same elements installed on another wheel seat10as described above. So, I will not describe them again.

Please refer toFIG. 6, wherein the retractable tubes21and22are extended and the trigger device56and the driven device57are located at the first positions. The shaft31runs through the first hole573of the driven device57and the second hole564of the trigger device56. At this time, the platform30is located at the extended position. The flat surfaces32of the shaft31are engaged with the flat surfaces566of the trigger device56that will stop the platform30to turn, in other words, the platform30will be secured at the extended position.

Please refer toFIG. 6, when the retractable tubes21and22are retracted to force the trigger device56and the driven device57to approach their second positions. The converting portions565and575will be in touch with the flat surfaces32of the shaft31and force the shaft to turn such that the platform30will be driven to turn upwards as shown in FIG.6.

As the second tube22move downwards continuously, please refer toFIG. 7, the trigger56and drive the driven device57will be driven to move to the second positions continuously and the shaft31will be driven to turn continuously. When the trigger56and drive the driven device57arrived the second positions, the shaft now is turned about 90 degrees. The shaft31, at this time, will enter the first hole563of the trigger device56and the second hole574of the driven device57. The platform30now will be turned to the collapsed position and the flat surfaces576of the driven device57will be engaged with the flat surfaces32of the shaft31to secure the platform30at the collapsed position.

If the user pulls the handle bar23to make the second tubes22no longer against the trigger device56, the first spring58will force the trigger device56and the driven device57moving back from the second positions to the first positions. The transferring means50will act reversibly such that the platform30will be turned to the extended position from the collapsed position. It has to be mentioned that the weight of the platform30will help the transferring means50to drive the platform30to turn downwards.

With the combination as described above, user only needs to operating the retractable handle20to retract and extend, it will drive the platform30to turn. In other words, user only needs to pull the retractable handle20to make it extended, the platform30will be driven to turn from the collapsed position to the extended position. Only one step is needed to operate, user can extend the collapsed handcart1of the present invention to carry goods on it and drive it to run. User also only need to push the retractable handle20to make it retracted, the platform30will be driven to turn from the extended position to the collapsed position to collapse the handcart1of the present invention.

FIG. 8shows a second type of transferring means60including a trigger device61and a driven device62. The trigger device61is similar to the corresponding element on the first preferred embodiment having an inclined surface611at an end thereof a pin612at interior side thereof and an elongated slot613. The driven device62is fixed with the shaft31of the platform30can rotate with the shaft31. The driving device62is provided with a driving surface622at a side thereof and is engaged with the pin612of the trigger device61. Such that the movement of the trigger device61will drive the driven device622to rotate, in the meantime, the platform will be driven to turn.

FIG. 9shows a third type of transferring means70including a trigger device71and a gear72. The trigger device71is similar to above element having a rack711. The gear72is fixed with the shaft31and engaged with the rack711of the trigger device. Such that the trigger device71can drive the platform30to turn.

FIG. 10shows a fourth type of transferring means80, which has a trigger device81having an inclined surface82at the end extending into the retractable tube. The trigger device81is fixed with the shaft31with spring83, so that the retractable tube can drive the trigger device81to turn and the trigger device81will drive the shaft31(the platform) to turn.