A strap-tightening device includes a frame, a handle connected to the frame and a reel located on the frame. A first detent is located on the frame. A second detent is located on the handle. The second detent includes two horns each including a downward prong and an upward prong. The reel includes a cylinder and two ratcheted wheels attached to the cylinder. The ratcheted wheels are engaged with the upward prongs of the horns of the second detent during pivoting of the handle in a direction to cause the cylinder to reel in a strap. The ratcheted wheels are engaged with the first detent during pivoting of the handle in an opposite direction to prevent the handle from spinning the cylinder to reel out the strap. A withdrawing unit spins the reel to withdraw the strap.

BACKGROUND OF INVENTION

1. Field of Invention

The present invention relates to a device for tightening two straps for tying goods on a truck.

2. Related Prior Art

There are various strap-tightening devices. Some of them are not equipped with drawing units so that the straps have to be manually reeled in, and this is inconvenient. The others are equipped with drawing units for automatically reeling in the straps; however, it is difficult to control the speed of the reeling of the straps, and people might get hurt by the hooks tied to the straps during the reeling.

To overcome the foregoing problem, a strap-tightening device can be equipped with a brake for controlling the speed of the reeling of a strap as disclosed in U.S. Pat. No. 7,503,736, Retractable Tie-Down with Rotation Brake, and Chinese Patent Publication No. 100391645, Strap-Tightening Device with Automatic Reeling. The brake is located on a frame. The brake does not interfere with the withdrawing of the strap normally. Only when a handle is located against the frame, can a first detent be operated to cause the brake to abut and slow the strap.

Because of limited space of the strap-tightening device, the brake inevitably reduces the space left for the strap or other elements, and increases the cost. This is bad for marketing the strap-tightening device as the prices of various materials get higher and higher around the world.

Moreover, when the handle is located against the frame, the first detent must be moved over a lobe formed on the frame in a direction and located against the lobe to restrain the handle from pivoting. The first detent must be moved over the lobe in an opposite direction to allow the pivoting of the handle. This is troublesome.

SUMMARY OF INVENTION

It is the primary objective of the present invention to provide a simple and secure strap-tightening device.

A strap-tightening device includes a frame, a handle connected to the frame and a reel located on the frame. A first detent is located on the frame. A second detent is located on the handle. The second detent includes two horns each including a downward prong and an upward prong. The reel includes a cylinder and two ratcheted wheels attached to the cylinder. The ratcheted wheels are engaged with the upward prongs of the horns of the second detent during pivoting of the handle in a direction to cause the cylinder to reel in a strap. The ratcheted wheels are engaged with the first detent during pivoting of the handle in an opposite direction to prevent the handle from spinning the cylinder to reel out the strap. A withdrawing unit spins the reel to withdraw the strap.

Other advantages and features of the present invention will be apparent from the following description referring to the drawings.

DETAILED DESCRIPTION OF PREFERRED EMBODIMENT

Referring toFIGS. 1 through 5, a strap-tightening device100includes a frame10, a handle20, a reel30, a withdrawing unit40, a first detent50, a second detent60, a first strap71and a second strap72according to the preferred embodiment of the present invention. The frame10includes a floor11extending between two walls12. Each of the walls12includes a stop17formed between two arched edges16and19. A slot52is defined in each of the walls12. A tab54extends vertically from the floor11.

The reel30includes a cylinder31and two ratcheted wheels32. The cylinder31includes two ends each connected to a related one of the ratcheted wheels32. The cylinder31is a hollow element with a slot34defined therein longitudinally.

The withdrawing unit40includes an axle14, a coil spring41and a shell42. The axle14includes a slot defined in an end.

The handle20includes an opening21defined therein and two lateral cams22extending forwards. The cams22are in parallel to each other. Each of the cams22includes a recess23defined in an upper section of an arched edge thereof and a lobe24formed on a lower section of the arched edge thereof.

The first detent50includes two wings51and a tail53extending backwards from a portion thereof between the wings51.

The second detent60includes two pivots61, two horns62extending forwards from a portion thereof between the pivots61and a tail63extending backwards from the portion between the pivots61. Each of the hors62includes a prong65extending downwards and a prong66extending upwards. The prongs66are located between the prongs65.

There is provided a spring64. The spring64includes a rectilinear section extending between two coil-shaped portions.

There is provided a lid15. The lid15includes a slot18defined therein.

In assembly, an end of each of the straps70and72is connected to a hook71. A crossbar13is inserted through a loop formed at another end of the first strap70. The ends of the crossbar13are connected to the walls12. A loop formed at another end of the second strap72is inserted into the cylinder31through the slot34.

The coil-shaped portions of the spring64are wound around the pivots61of the handle20. The pivots61of the second detent60are inserted in two 8-figured apertures defined in the handle20so that the second detent60is pivotally connected to the handle20.

A helical spring55is provided around the tail53of the first detent50before the tail53of the first detent50is inserted through an aperture defined in the tab54of the frame10. The wings51of the first detent50are movably located in the slots52of the frame10. Thus, the helical spring55is compressed between the second detent50and the tab54.

The axle14is inserted through an aperture defined in each of the walls12of the frame10, an aperture defined in each of the cams22of the handle20, an aperture defined in each of the ratcheted wheels32, the cylinder31, and the loop of the second strap72. Thus, the handle20and the ratcheted wheels32are rotationally connected to the frame10. The axle14is securely connected to one of the ratcheted wheels32, i.e., there is no relative rotation between them. The prongs66are engaged with the ratcheted wheels32.

An internal end of the coil spring41is inserted through the slot of the axle14. An external end of the coil spring41is securely connected to an internal portion of the shell42. The shell42is securely connected to one of the walls12of the frame10. The lid15is pivotally connected to the walls12of the frame10. The lid15covers the ratcheted wheels32. The hook71tied to the second strap72is inserted through the slot18of the lid15. Thus, a section of the second strap72is also inserted through the slot18of the lid15.

Referring toFIGS. 3 and 4, the handle20is located against or near the frame10. The lobes24of the cams22of the handle20are abutted against the wings51of the first detent50, thus disengaging the wings51from the ratcheted wheels32. As the second detent60is biased by the spring64, the prongs65are restrained by the stops17. Thus, the handle20cannot be pivoted from the frame10. The lower side of each of the prongs66is located against an inclined edge of one of the ratchets33of a related one of the ratcheted wheels32. A counterclockwise torque exerted on the reel30by the coil spring41is encountered by a clockwise torque exerted on the reel30by the spring64. Thus, the second strap72cannot be withdrawn or reeled in automatically.

Referring toFIG. 5, a force F is exerted on the second strap72. A clockwise torque exerted on the reel30because of the force F overcomes the counterclockwise torque exerted on the reel30by the coil spring41. The second strap72begins to be reeled out. Even on the moment when the tip of one of the ratchets33of each of the ratcheted wheels32comes into contact with a related one of the prongs66, the clockwise torque exerted on the reel30because of the force F is large enough to overcome the sum of the counterclockwise torque exerted on the reel30by the coil spring41and a counterclockwise torque exerted on the reel30by the spring64. Thus, the second strap72continues to be reeled out.

Once the second strap72is stopped, the strap-tightening device100is returned back to the status shown inFIGS. 3 and 4. Thus, the second strap72cannot be withdrawn automatically. Hence, a user would not get hurt by automatic withdrawing of the second strap72or the hook71during the operation of reeling out the second strap72. The hook71tied to the second strap72can be hooked onto a truck for example.

Referring toFIG. 6, the tail63of the second detent60is pressed down with a finger or any proper tool inserted through the opening21. Thus, the horns62are lifted, and the prongs65are removed from the arched edges19and the stops17. Hence, the handle20can be pivoted from the frame10without spinning the reel30.

Referring toFIGS. 7 and 8, the tail63of the second detent60is released. Thus, the tip of each of the horns62is abutted against the vertical edge of one of the ratchets33of a related one of the ratcheted wheels32. Each of the prongs65is in contact with or away from a related one of the arched edges16by a small gap.

Referring toFIGS. 9 and 10, the handle20is pivoted further from the frame10to spin the reel30to reel in the second strap72. Therefore, the first strap70and the second strap72are tightened.

To withdraw the second strap72for storage, the hook71tied to the second strap72is disengaged from the truck. Then, the tail63of the second detent60is pressed down with a finger or any proper tool inserted through the opening21as shown inFIG. 6. Thus, the horns62are lifted, and the prongs66are disengaged from the ratchets33. Hence, the coil spring41is allowed to automatically spin the reel30to withdraw the second strap72.

In practice, the tail63of the second detent60may not have to be pressed all the way down to allow the coil spring41to automatically spin the reel30to withdraw the second strap72while the ratchets33hit and move past the prongs66. Thus, clicks are made to let any persons near the hook71tied to the second strap72know that they are withdrawn.