Rear wheel synchronous brake system for pushcart

A rear wheel synchronous brake system used in a pushcart such as a baby jogging stroller is disclosed to include two rear brakes respectively coupled to the two rear wheels of the baby jogging stroller, a hand control unit mounted on the handle of the baby jogging stroller at the top, and two brake lines coupled between the brake lever of the hand control unit and the two rear brakes for driving the rear brakes to brake the two rear wheels of the baby jogging stroller synchronously when the user pulling the brake lever.

BACKGROUND AND SUMMARY OF THE INVENTION

The present invention relates to a pushcart and more specifically, to a rear wheel synchronous brake system for pushcart that can conveniently be operated to synchronously stop the two rear wheels of the pushcart. The present invention is practical for use in a push card having a front flywheel.

A baby jogging stroller or baby stroller has at least one front wheel and two rear wheels. A baby jogging stroller is designed to carry a baby or young child for pushing by a person who is jogging. A baby stroller is a small carriage in which a baby or child is pushed around. A regular three-wheel type baby cart includes one front wheel and two rear wheels. The front wheel is a flywheel. A baby cart of this design must have the brake system set to stop the rear wheels.FIG. 1shows a brake system used in a baby jogging stroller. According to this design, the brake system92has a brake pedal921for pressing by leg to stop the two rear wheels91of the baby jogging stroller. It is inconvenient and dangerous to operate this brake system when jogging.

The present invention has been accomplished under the circumstances in view. It is therefore one object of the present invention to provide a rear wheel synchronous brake system for pushcart, which is convenient to operate. It is another object of the present invention to provide a rear wheel synchronous brake system for pushcart, which is safe in use. It is still another object of the present invention to provide a rear wheel synchronous brake system for pushcart, which is suitable for use in a pushcart that has a front flywheel. To achieve these and other objects of the present invention, the rear wheel synchronous brake system comprises two rear brakes respectively coupled to the two rear wheels of the baby jogging stroller, a hand control unit mounted on the handle of the baby jogging stroller at the top, and two brake lines coupled between the brake lever of the hand control unit and the two rear brakes for driving the rear brakes to brake the two rear wheels of the baby jogging stroller synchronously when the user pulling the brake lever. When the user pulling the brake lever, the steel wires of the two brake lines are driven to move the rear brakes synchronously, thereby causing the rear brakes to brake the two rear wheels of the baby jogging stroller. On the contrary, when the user released the hand from the brake lever, the rear brakes are reversed by respective torsional springs to move the respective brake shoes away from the rear wheels. Because the brake system is operable by the hand control unit through the hand-operated brake lever, the brake system assures high safeness. The user can pull the brake lever with the hand to stop the cart instantly upon occurrence of an unexpected sudden condition during jogging.

DETAILED DESCRIPTION OF THE INVENTION

Referring toFIGS. 2 and 3, a rear wheel synchronous brake system is shown used in a pushcart. According to this embodiment, the pushcart is a baby jogging stroller. The baby jogging stroller3comprises a front wheel30, and two rear wheels32. The rear wheel synchronous brake system comprises a hand control unit1and two rear brakes2. The hand control unit1is installed in the handle31of the baby jogging stroller3at the top side. The hand control unit1comprises a brake lever11and two brake lines4. The respective steel wires41of the brake lines4are respectively connected to the rear brakes2. When the user pulls the brake lever11, the steel wires41of the brake lines4are driven to move the rear brakes2against the rear wheels32respectively, thereby stopping the rear wheels32. The rear wheels32have the respective hub321respectively mounted with a respective wheel axle3211, which is supported in an axle hole511in an axle holder51at one end of a rear wheel holder5(seeFIG. 7).

The main features of the present invention are outlined hereinafter. Each rear brake2is controlled to brake the brake shaft3212of the hub321of the respective rear wheel32(seeFIGS. 3˜9), comprising a base block21, a locating frame22, a brake shoe23, a link24, and a torsional spring7.

The base block21has a bottom wall211, a peripheral wall212perpendicularly extending around the border of the bottom wall211, a mounting hole2111formed the bottom wall211near the top side (seeFIG. 12), a coupling hole2112formed in the bottom wall211near the bottom side remote from the mounting hole2111and coupled to one axle holder51of the rear wheel holder5of the baby jogging stroller3(seeFIGS. 4˜10), and a side hole2112cut through the peripheral wall212. A fastening member, for example, a pivot bolt61is mounted in the mounting hole2111of the base block21and inserted through the link24and the torsional spring7to secure the base block21to the rear wheel holder5of the baby jogging stroller3. The bottom side of the bottom wall211is fastened to the brake shoe23. The peripheral wall212has the top side thereof fastened to the locating frame22.

The locating frame22has one side221fastened to the top side of the peripheral wall212with a hollow screw63and a nut64(seeFIGS. 9 and 10). The steel wire41of one of the aforesaid brake lines4is inserted through the hollow screw63into the inside of the base block21.

The brake shoe23is shaped like a split ring (seeFIGS. 9 and 10), having a first end231fastened to the bottom side of the bottom wall211of the base block21with a fastening member62, and a second end232fastened to the link24.

The link24is a substantially V-shaped bar, having a first arm241fastened to one end of the steel wire41of one of the aforesaid two brake lines4with a screw66and a washer661, a second arm242fastened to the second end232of the brake shoe23with a fastening member65, a middle connecting portion240joining one end of the first arm241and one end of the second arm242(seeFIGS. 9 and 10), and a pivot hole2401cut through the middle connecting portion240and coupled to the pivot bolt61in the mounting hole2111of the base block21.

The torsional spring7has one end71hooked on the locating frame22, and the other end72hooked on the first arm241of the link24.

When the user pulls the brake lever11of the hand control unit1, the steel wires41of the brake lines4are driven to move the first arm241of the link24of each of the rear brakes2and to further bias the links24of the two rear brakes2, thereby causing the second arm242of the link24of each rear brake2to move the second end232of the brake shoe23of the respective rear brake2toward the first end231of the respective brake shoe23to brake the brake shaft3121of the hub321of the respective rear wheel32(seeFIG. 11), and therefore the rear wheels32are stopped. On the contrary, when the user released the brake lever11, the torsional spring7reverses the link24of the respective rear brake2to move the second end232of the brake shoe23of the respective rear brake2away from the first end231of the respective brake shoe23(seeFIG. 10), and therefore the brake action is released.

Referring toFIG. 7, the brake shaft3212of the hub321of each rear wheel32has a rough surface to enhance the braking effect. The brake shaft3212is secured to the respective wheel axle3211by a C-shaped clamp3215, having an axially extending axle hole3213and an axle bearing3214mounted in the axle hole3213to support the wheel axle3211.

Referring toFIG. 9, the base block21of each rear brake2further has a plurality of locating holes210for the mounting of a cover25. The cover25has a plurality of locating holes250respectively fastened to the locating holes210of the base block21with fastening members67,68(seeFIG. 5), and a through hole251for the passing of the brake shaft3212of the respective rear wheel32.

Referring toFIGS. 14˜18, the hand control unit1is comprised of the aforesaid brake lever11, a holder frame12, and the aforesaid two brake lines4.

The holder frame12has a coupling block121extended from one end thereof, a clamping plate122pivotally connected to the free end of the coupling block121with a pivot1211and secured with the coupling block121to the handle31of the baby jogging stroller3by a tightening up screw1221, a receiving chamber120transversely disposed at the other end remote from the coupling block121for receiving the brake lever11, three pivot holes, namely, the first pivot hole1231, the second pivot hole1232and the third pivot hole1233respectively perpendicularly extending from the receiving chamber120to the outside wall (seeFIG. 15), a pulley127mounted in the receiving chamber120and pivotally connected to the third pivot hole1233with a pivot1271for guiding the steel wire411of one of the two brake lines4, and two brackets1281,1282respectively fixedly provided at two opposite sides to hold the brake lines4in place.

The brake lever11has a coupling block114extended from one end thereof, namely, the front end and inserted into the receiving chamber120of the holder frame12and pivotally connected to the second pivot hole1232with a pivot1242, a crevice112transversely disposed in the front end, an elongated sliding slot110extending across the crevice112and pivotally coupled to the first pivot hole1231inside the receiving chamber120of the holder frame12with a rivet1241and a spring member125, and two locating pins, namely, the first locating pin111and the second locating pin113respectively set in the crevice112.

The steel wire41of one of the brake lines4has one end411inserted through one bracket1281and fastened to the first locating pin111of the brake lever11, and the other end connected to one of the aforesaid two rear brakes2. The steel wire41of the other end of the brake lines4has one end412inserted through the other bracket1282and extending over the pulley127in the receiving chamber120of the holder frame12and then fastened to the second locating pin113of the brake lever11, and the other end connected to the other one of the aforesaid two rear brakes2.

Referring toFIG. 12, the base block21further has a locating hole2113formed in the bottom wall211and fastened to the first end231of the brake shoe23with a fastening member62.

As indicated above, the rear wheel synchronous brake system of the present invention has the following advantages:

1. Ease of operation: When wishing to stop the cart, the user needs only to pull the brake lever11of the hand control unit1. When pulling the brake lever11, the steel wires41of the brake lines4are driven to bias the links24of the rear brakes2, thereby causing the brake shoes23of the rear brakes2to brake the brake shafts3121of the hubs321of the rear wheels32synchronously; on the contrary, when the user released the brake lever11, the respective torsional springs7reverse the links24of the rear brakes2respectively, thereby releasing the brake shoes23of the respective rear brakes2from the brake shafts3121of the hubs321of the rear wheels32respectively.

2. High safeness: Because the rear wheel braking operation is controlled by hand through the brake lever11, the user can pull the brake lever11with the hand to stop the cart instantly upon occurrence of an unexpected sudden condition during jogging.

3. The rear wheel synchronous brake system is practical for use in a baby jogging stroller, which is equipped with a flywheel type front wheel.

Although a particular embodiment of the present invention has been described in detailed for purposes of illustration, various modifications and enhancements may be made without departing from the spirit and scope of the invention. Accordingly, the invention is not to be limited except as by the appended claims.