CONTROL DEVICE FOR FASTENING STRAP UNIT

Abstract

A fastening strap unit includes a frame with a mandrel and a strap connected thereto. The strap is wrapped to the mandrel, and the first end of the strap is fixed to the mandrel and a hook is connected to the second end of the strap. A shaft extends from the frame and a motor drives the shaft which drives the mandrel. A first sensing chip is connected to the second end of the strap and a second sensing chip is connected to the first end of the strap. A sensor is connected to the frame so as to detect the first sensing chip or the second sensing chip when the strap is retracted or released to its final position, and the motor is stopped.

Description

BACKGROUND OF THE INVENTION

(1) Field of the Invention

The present invention relates to a fastening strap unit, and more particularly, to a control device for a fastening strap unit so as to protect the motor when the strap is released or retracted to the final position.

(2) Description of the Prior Art

The conventional fastening strap unit is usually used to secure an object such as a wheelchair, machine and box, and generally comprises a mandrel, a strap, an operation device and a motor. The strap is wrapped to the mandrel and can be released or retracted relative to the mandrel. The motor drives the operation device to release and retract the strap. The strap has a hook which is hooked to the object and the strap is released or retracted to a desired length so as to position the object in a vehicle or a fixed object.

However, if the strap is overly released or retracted, the motor will be overloaded to damage the power system of the unit.

The present invention intends to provide a control device for a fastening strap unit and the movement of the strap automatically stops to protect the motor.

SUMMARY OF THE INVENTION

The present invention relates to a fastening strap unit and comprises a frame having a mandrel and a strap connected thereto. The strap is wrapped to the mandrel. The strap has a first end fixed to the mandrel and a hook is connected to a second end of the strap. A shaft extends from the frame and a motor drives the shaft which drives the mandrel. A first sensing chip connected to the second end of the strap and a second sensing chip is connected to the first end of the strap. A sensor is connected to the frame and detects the first sensing chip or the second sensing chip to stop the motor.

The primary object of the present invention is to provide a control device of a fastening strap unit, the motor is stopped when the strap is released or retracted to its final position, such that the motor is protected from being overloaded.

The present invention will become more obvious from the following description when taken in connection with the accompanying drawings which show, for purposes of illustration only, a preferred embodiment in accordance with the present invention.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a perspective view to show the fastening strap unit of the present invention;

FIG. 2 is a perspective view to show the strap wrapped to the mandrel and the strap has a hook and a sensing chip;

FIG. 3 is a plan view to show that the strap is retracted to the mandrel;

FIG. 4 is a plan view to show the fastening strap unit of the present invention, and

FIG. 5 is a plan view to show that the strap is released from the mandrel.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT

Referring to FIGS. 1 to 5, the fastening strap unit of the present invention comprises a U-shaped frame 10 and a board 11 extends from two sides of the frame 10. A mandrel 12 and a strap 13 are located between two sidewalls of the frame 10 and the strap 13 is wrapped to the mandrel 12. The mandrel 12 is rotatably connected between the two sidewalls of the frame 10. The strap 13 has the first end fixed to the mandrel 12 and a hook 133 is connected to the second end of the strap 13. A first sensing chip 131 is connected to the second end of the strap 13 and a second sensing chip 132 is connected to the first end of the strap 13. In this embodiment, each of the first and second sensing chips 131, 132 is a metal chip. A sensor 15 is connected to the frame 10 and detects the first sensing chip 131 or the second sensing chip 132 to stop the motor 50.

A shaft 122 co-axially connected to the mandrel and extends from the frame 10. The motor 50 drives the shaft 122 which drives the mandrel 12 so as to release or retract the strap 13.

The frame 10 is fixed to a fixed object such as a vehicle by the board 11, and the strap 13 is pulled to an object such as a wheelchair (not shown), the hook 133 hooks to the object and the mandrel 12 and the strap 13 are stopped. Therefore, the object is positioned by the strap 13 as shown in FIG. 3.

When retrieving the strap 13, the hook 133 is unhooked from the object, the motor 50 is activated to drive the shaft 122 and the mandrel 12 to retract the strap 13. It is noted that the user can simply pull the strap 13 and to hook the hook 133 to the object manually. The retrieving of the strap 13 can be done by using the motor 50.

When the strap 13 is released or retracted, the sensor 15 detects the first sensing chip 131 or the second sensing chip 132 passing there by, and the detection sends a signal to the motor 50 to stop the motor 50. By this way, the motor 50 is stopped and protected when the strap 13 is released or retracted to its final position.

While we have shown and described the embodiment in accordance with the present invention, it should be clear to those skilled in the art that further embodiments may be made without departing from the scope of the present invention.

Claims

1. A fastening strap unit comprising:

a frame having a mandrel and a strap connected thereto, the strap wrapped to the mandrel, the strap has a first end fixed to the mandrel and a hook connected to a second end of the strap, a shaft extending from the frame and a motor driving the shaft which drives the mandrel, a first sensing chip connected to the second end of the strap and a second sensing chip connected to the first end of the strap, and

a sensor connected to the frame and detecting the first sensing chip or the second sensing chip to stop the motor.

2. The unit as claimed in claim 1, wherein each of the first and second sensing chips is a metal chip.