Fixing device

A fixing device for fixing a workpiece defining a hole, includes a fixing shaft, a sliding bar, and a sliding block. The fixing shaft is configured to be inserted in the hole of the workpiece and defines a groove therein along an axial direction thereof. The sliding bar is mounted to the fixing shaft and movable in the groove along the axial direction. The sliding block is mounted to the fixing shaft and movable in the groove along a radial direction of the fixing shaft. When the sliding bar moves forward along the axial direction, the sliding block is moved toward the sliding bar along the radial direction. When the sliding bar moves backward along the axial direction, the sliding block is driven to move away from the sliding bar along the axial direction to urge against a wall bounding the hole of the workpiece to fix the workpiece.

BACKGROUND

1. Field of the Invention

The present invention relates to fixing devices, and especially relates to a fixing device for fixing a workpiece defining a hole therein.

2. Description of Related Art

In machining or testing a workpiece, it is important to fasten the workpiece, which directly affects an accuracy of machining or testing.

For a workpiece defining a hole therein, which needs to be fastened via the hole, it is typically fastened by one of two ways.

Referring toFIG. 1, in one way, the workpiece1is clamped by two mandrels2, with heads of the mandrels2partly inserted into the hole from opposite sides of the workpiece1respectively. However, in this way, the hole of the workpiece1should only be a through hole or the workpiece1should has two holes having a same axis and defined at opposite sides of the workpiece1, and the workpiece is often skewed when clamped because a height H1of one of the mandrels2may not equal to a height H2of the other one of the mandrels2.

Referring toFIG. 2, in the other way, the workpiece1is fastened by a mandrel4, with a head of the mandrel4being inserted into the hole of the workpiece1. However, because the hole of the workpiece1may not be accurately machined, a size of the hole may be greater or smaller than the head of the mandrel4. When the size of the hole is smaller, the head of the mandrel4cannot be inserted into the hole. When the size of the hole is greater, a clearance can be formed around the head of the mandrel4in the hole, which leads to the workpiece1not being securely fastened.

What is needed is to provide a fixing device for fastening a workpiece with a hole therein.

SUMMARY

An embodiment of a fixing device for fixing a workpiece defining a hole therein, includes a fixing shaft, a sliding bar, and a sliding block. The fixing shaft configured to be inserted into the hole of the workpiece, defines a groove therein along an axial direction thereof. The sliding bar is mounted to the fixing shaft and movable in the groove of the fixing shaft along the axial direction. The sliding block is mounted to the fixing shaft and movable in the groove of the fixing shaft along a radial direction of the fixing shaft. When the sliding bar moves forward along the axial direction, the sliding block is moved toward the sliding bar along the radial direction. When the sliding bar moves backward along the axial direction, the sliding block is driven to move away from the sliding bar along the axial direction to urge against a wall bounding the hole of the workpiece to securely fix the workpiece.

Other advantages and novel features of the present invention will become more apparent from the following detailed description of an embodiment when taken in conjunction with the accompanying drawings, in which:

DETAILED DESCRIPTION

Referring toFIG. 3, a fixing device in accordance with an embodiment of the present invention for fixing a workpiece1with a hole (seeFIG. 4) defined therein, includes a button10, a turning member20, a spring30, a sliding bar40, a T-shaped sliding block50, a supporting board60, and a fixing shaft70.

The button10includes a circular operating portion16, a column portion12coaxially extending from the operating portion16, and a screw portion14coaxially extending from the column portion12.

The turning member20includes a great column portion, and a small column portion coaxially extending from the great column portion. A plurality of skid-proof striae is formed on a circumference of the great column portion. A through hole22is defined in the turning member20along an axis thereof corresponding to the column portion12of the button10. A plurality of assembly holes24is defined in the turning member20around the through hole22.

The sliding bar40includes a strip42, and a wedge-shaped piece44extending from a side of the strip42adjacent an end thereof. A screw hole46(seeFIG. 5) is defined in the other end of the strip42. The piece44includes an inclined surface at a top thereof. A width of the strip42is greater than that of the piece44.

The T-shaped sliding block50includes a rectangular horizontal piece52, and a wedge-shaped vertical piece54perpendicularly extending from a bottom of the horizontal piece52. Both sides of the horizontal piece52are arc-shaped. An assembly hole56is defined in the vertical piece54. The vertical piece54has an inclined surface at a bottom thereof, corresponding to the inclined surface of the piece44of the sliding bar40. A width of the vertical piece54is equal to that of the piece44of the sliding bar40.

The supporting board60is rectangular-shaped, and configured to be secured to a machining or testing apparatus for locating the fixing shaft70. An opening62is defined in the supporting board60.

The fixing shaft70includes a column-shaped rotating part72corresponding to the opening62of the supporting board60, a fixing part76, and a blocking part74connected between the rotating part72and the fixing part76. The rotating part72, the blocking part74, and the fixing part76are coaxial. A through hole78is defined in the fixing shaft70along the axis thereof. The fixing part76is a column that is partly cutaway, such that two inclined surfaces762are symmetrically formed on a side of the fixing part76. A slot768is defined in the fixing part76between the two inclined surfaces762and communicated with the through hole78. A groove764is defined in each inclined surface762with a wall formed between the slot768and the groove764. The grooves764are in alignment with each other. Two elliptic holes766are respectively defined in the walls in alignment with each other. A plurality of screw holes722(seeFIG. 5) is defined in a free end surface of the rotating part72corresponding to the assembly holes24of the turning member20.

Referring also toFIGS. 4 to 6, in assembly, the free end of the rotating part72of the fixing shaft70is inserted though the opening62of the supporting board60and the blocking part74of the fixing shaft70touches the supporting board60. The turning member20is fixed to the free end of the rotating part72of the fixing shaft70via a plurality of screws80being inserted through the assembly holes24of the turning member20and engaged in the corresponding screw holes722of the fixing shaft70, such that the supporting board60is sandwiched between the blocking part74of the fixing shaft70and the turning member20, and the rotating part72of the fixing shaft70is rotatably mounted to the supporting board60. An end defining the screw hole46of the sliding bar40is inserted through the through hole78of the fixing shaft70and received in the through hole22of the turning member20, with the wedge-shaped piece44of the sliding bar40received in the slot768of the fixing shaft70. The spring30is fitted about the strip42of the sliding bar40and received in the through hole22of the turning member20. The button10is fixed to the fixing shaft70via the screw portion14thereof being engaged in the screw hole46of the sliding bar40, such that the spring30is sandwiched between the column portion12of the button10and the rotating part72of the fixing shaft70, and the column portion12of the button10can move into the through hole22of the turning member20with deformation of the spring30. The vertical piece54of the T-shaped sliding block50is received in the slot768of the fixing shaft70with the inclined surface thereof engaged with the inclined surface of the piece44of the sliding bar40. A pin90is inserted through one elliptic hole766of the fixing shaft70, and through the assembly hole56of the sliding block50, and engaged in the other elliptic hole766of the fixing shaft70, such that the pin90together with the sliding block50can be moved up and down along the elliptic holes766.

In use, the button10is pressed to drive the sliding bar40together with the button10to slide along the through hole78of the fixing shaft70and the spring30is compressed, such that the T-shaped sliding block50can be moved down along the inclined surface of the wedge-shaped piece44of the sliding bar40because of the gravity. Thus, a size of the assembly of the fixing part76of the fixing shaft70and the sliding block50is reduced so as to be capable of being inserted into the hole of the workpiece1. The button10is released, and the spring30rebounds to drive the button10together with the sliding bar40to move back. The T-shaped sliding block50is driven to slide along the inclined surface of the wedge-shaped piece44of the sliding bar40to move upward, with the horizontal piece52of the sliding block50urging against a wall bounding the hole of the workpiece1, such that the workpiece1is fixed to the fixing shaft70. The turning member20can be operated to rotate the workpiece1. In other embodiments, the turning member20can be replaced by a motor driven gear.

Moreover, in other embodiments the spring30can be replaced by some other device, such as an air pressure device or a hydraulic pressure device capable of performing a same function.