Telescopic hand tool

Abstract

A telescopic hand tool consists of a main body, a bar and a positioning device. The bar possesses an axial hole bored axially from its one end for engaging with a telescopic bar of the main body, and a sliding groove dug around its surface, bored with a ball hole. The positioning device includes a restricting knob, a compression spring and a restricting plate. The restricting knob can slide restrictively along within the sliding groove by means of a restricting block so as to let the main body move in the bar axially. The compression spring can push elastically the restricting knob back to its original position to press on a steel ball restricted in a restricting ball hole of the main body, keeping the main body locked restrictively in the bar.

Description

BACKGROUND OF THE INVENTION

1. Field of the Invention

This invention relates to a hand tool, particularly to one that can be adjusted telescopically and kept immovably by means of a knob able to re-position automatically.

2. Description of the Prior Art

Commonly, as shown in FIG. 1, a conventional telescopic hand tool 10 is composed of a main body 11, a bar 12, a controlling cover 13, a compression spring 14 and a C-shaped lock washer 15. The main body 11 is provided with plural restricting ball holes 111 bored axially with equidistance and a shallow groove 112 concaved to communicate with the restricting ball holes 111. The bar 12 is provided with a positioning hole 121 bored at its one end for a positioning ball 122 to stay on, and an annular slot 123 bored around a certain spot. The controlling cover 13 is provided with a controlling groove 131 and an accommodating groove 132 formed respectively on its inner wall of two opposite sides and spaced apart by a blocking projection edge 133 provided with a controlling slope 1331 formed at its one side. The compression spring 14 is mounted on the bar 12. When the length of the hand tool is to be adjusted, the controlling cover 13 has to be moved toward the C-shaped lock washer 15 fitted in the annular slot 123, keeping the controlling slope 1331 of the controlling cover 13 separated from the positioning ball 122 but staying in the controlling groove 131 without being restricted by the restricting ball holes 111 and the shallow groove 112. Thus, the main body 11 can be moved to a desired location and positioned restrictively while releasing the controlling cover 13 to move back to its original location, keeping the positioning ball 122 fitted restrictively in another restricting ball hole 111 again. But, it is so inconvenient that the controlling cover 13 has to be continuously dragged axially while adjusting the length of the main body 11. Moreover, the compression spring 14 is installed between the controlling cover 13 and the bar 12, not only relatively increasing a gap between the controlling cover 13 and the bar 12 but also apt to cause the controlling cover 13 moving vacillatingly along the bar 12.

SUMMARY OF THE INVENTION

The objective of this invention is to offer a telescopic hand tool.

The main characteristics of the invention are a main body, a bar and a positioning device. The bar is provided with an axial hole bored axially from its one end for engaging with a telescopic bar of the main body, and a sliding groove dug around its surface, bored with a ball hole. The positioning device is composed of a restricting knob, a compression spring and a restricting plate. The restricting knob can slide restrictively along the sliding groove by means of a restricting block so as to let the main body move in the bar axially. The compression spring can push elastically the restricting knob back to its original position to press on a steel ball constrained in a restricting ball hole of the main body, keeping the main body locked restrictively in the bar. Therefore, by means of the restricting block of the restricting knob keeping the steel ball in the restricting ball hole immovably, the main body is positioned precisely and stably in the bar. And, the compression spring can elastically push the restricting knob back to its original position to restrict the steel ball from moving. The restricting knob can be just operated to move right or left by a finger for adjusting the length of the main body, conforming with requirements of humanization and simplification.

BRIEF DESCRIPTION OF DRAWINGS

This invention is better understood by referring to the accompanying drawings, wherein:

FIG. 1 is a cross-sectional view of a conventional telescopic hand tool;

FIG. 2 is a perspective view of a first preferred embodiment of a telescopic hand tool in the present invention;

FIG. 3 is an exploded perspective view of the first preferred embodiment of a telescopic hand tool in the present invention;

FIG. 4 is a cross-sectional view of the first preferred embodiment of a telescopic hand tool in the present invention, showing its main body positioned restrictively by its bar;

FIG. 5 is a cross-sectional view of the first preferred embodiment of a telescopic hand tool in the present invention, showing the main body loosened by the bar to move in the bar;

FIG. 6 is a cross-sectional view of the first preferred embodiment of a telescopic hand tool in the present invention, showing how the main body be positioned restrictively by the bar;

FIG. 7 is a cross-sectional view of the first preferred embodiment of a telescopic hand tool in the present invention, showing how the main body be loosened by the bar; and

FIG. 8 is a partial exploded perspective view of a second preferred embodiment of a telescopic hand tool in the present invention.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT

As shown in FIGS. 2 and 3, a first preferred embodiment of a telescopic hand tool in the present invention is composed of a main body 20, a bar 30 and a positioning device 40.

The main body 20 is provided with a working head 21 formed in its front portion and a telescopic bar 22 formed in its rear portion. The working head 21 is provided with a ratchet set 211 for engaging with a tool. The telescopic bar 22 formed cylindrical is provided with plural restricting ball holes 221 bored axially with equidistance, and a shallow groove 222 concaved with a depth lower than that of the restricting ball holes 221, for communicating with the restricting ball holes 221.

The bar 30 formed as an annular column is provided with an axial hole 31 bored axially from its one end for engaging with the telescopic bar 22 of the main body 20, a sliding groove 32 dug near the opening of the axial hole 31 to form as a two-step ladder, and a ball hole 33 bored in the sliding groove 32 for a steel ball 34 to fit in. The diameter of the ball hole 33 is slightly larger than that of the steel ball 34, enabling the steel ball 34 positioned restrictively in the restricting ball holes 221 of the main body 20. In addition, the bar 30 is also provided with a projection 35 planted longitudinally at two sides of the sliding groove 32 respectively and a grip 36 wrapped around a portion opposite to the axial hole 31 for a user to hold.

The positioning device 40, as shown in FIGS. 4˜6, is fixed on the sliding groove 32 of the bar 30, provided with a restricting knob 41, a compression spring 42 and a restricting plate 43. The restricting knob 41 is provided with a restricting block 411 located at its bottom side to correspond with the sliding groove 32, able to keep the restricting knob 41 sliding along the sliding groove 32, and a push key 412 formed triangular on its top side for a user to easily push it to keep the restricting knob 41 sliding along the sliding groove 32. The restricting knob 41 is in addition provided with a wing 413 formed at its two curved sides respectively, corresponding to the sliding groove 32. The compression spring 42 is installed in the sliding groove 32 and constrained by the restricting block 411 while sliding the restricting knob 41, keeping one end of the compression spring 42 contacted with the sliding groove 32 and the other end leaned on the restricting block 411, so that the restricting knob 41 can be pushed back to its original position by the compression spring 42 elastically. The restricting plate 43 is formed as an arc-like plate to correspond with the sliding groove 32 of the bar 30, provided with an elongate opening 431 shaped rectangular cut in its central portion to correspond with the sliding groove 32 for the restricting knob 41 to fit through to enable the restricting plate 43 fixed at two edges of the sliding groove 32, keeping the push key 412 exposed outside. The restricting plate 43 is additionally provided with a restricting portion 432 formed at two sides of the elongate opening 431 respectively, able to press on the wings 413 of the restricting knob 41 to let the restricting knob 41 slide along the sliding groove 32. In addition, there is a positioning hole 433 bored at two sides of the restricting plate 43 respectively for correspondingly fitting with the projection 35. Finally, the restricting plate 43 is restrictively fixed on the edge of the sliding groove 32. Though the restricting knob 41 and the restricting plate 43 are preferably made of metal, they can also be made of plastics easily formed into a variety of shapes.

In assembly, as shown in FIGS. 3 and 4, the steel ball 34 is first put in the ball hole 33 of the sliding groove 32 of the bar 30 and the restricting block 411 of the restricting knob 41 is fitted in the sliding groove 32 to enable the restricting knob 41 to slide along the sliding groove 32. When the main body 20 is moved to a desired position, the steel ball 34 is to sink in one of the restricting ball holes 221 to let the restricting knob 41 move to the top of the steel ball 34, keeping the steel ball 34 pressed by the restricting block 411 to be fitted in one of the restricting ball hole 221 to make the main body 20 positioned restrictively in the bar 30. Next, install the compression spring 42 between the sliding groove 32 and the restricting block 411 for elastically pushing the restricting knob 41 back to its original position after having been pushed away. Then, put the restricting plate 43 on the sliding groove 32 and keep the positioning holes 433 engaged with the projections 35, so that the restricting plate 43 is fixed above the sliding groove 32 of the bar 30. Spontaneously, the wings 413 of the restricting knob 41 are pressed by the restricting portion 432 of the restricting plate 43 to constrain the restricting knob 41 to slide along within the sliding groove 32.

In using, as shown in FIGS. 5˜7, the knob 412 of the restricting knob 41 has to be pushed to keep the restricting block 411 moved away from the steel ball 34, enabling the steel ball 34 released from the restricting ball hole 221 to move up in the shallow groove 222, so that the main body 20 can freely move to and fro in the bar 30. As the main body 20 is adjusted to another new position, the steel ball 34 is to spontaneously sink in one of the restricting ball holes 221 again. Then, as shown in FIGS. 4 and 6, the restricting knob 41 is allowed to move back elastically by the compression spring 42 to keep the steel ball 34 pressed by the restricting block 411, correspondingly positioning the steel ball 34 in that one of the restricting ball holes 221 and restricting the main body 20 from moving in the bar 30.

As shown in FIG. 8, a second preferred embodiment of a telescopic hand tool in the present invention has the same components as the first embodiment does except those described below. There are two female-threaded holes 37 bored at two sides of the sliding groove 32 respectively. The restricting plate 43 is provided with two through holes 434 bored at its two sides respectively, corresponding to the female-threaded holes 37 for screws 38 to pass through to screw fixedly with the female-threaded holes 37, keeping the restricting plate 43 fixed on the sliding groove 32 of the bar 30. In addition, an arrow mark 435 is printed on an outer surface of the restricting plate 43 to indicate the direction for a user to operate the restricting knob 41.

The advantages of the invention are abbreviated below as can be seen from the foresaid description. By means of the restricting block 411 of the restricting knob 41 keeping the steel ball 34 in the restricting ball hole 221 immovably, the main body 20 is positioned precisely and stably in the bar 30. And, the compression spring 42 can elastically push the restricting knob 41 back to its original position to restrict the steel ball 34 from moving easily. The restricting knob 41 can be just operated to move right or left by a finger for adjusting the length of the main body 20, conforming with requirements of humanization and simplification.

While the preferred embodiment of the invention has been described above, it will be recognized and understood that various modifications may be made therein and the appended claims are intended to cover all such modifications that may fall within the spirit and scope of the invention.

Claims

1. A telescopic hand tool comprising:

a main body provided with a working head formed in its front portion for engaging with a tool and a telescopic bar formed in its rear portion, said telescopic bar provided with plural restricting ball holes bored axially and a shallow groove concaved to communicate with said restricting ball holes, said restricting ball holes having a depth deeper than that of said restricting ball holes;

a bar provided with an axial hole bored axially from its one end for engaging with said telescopic bar of said main body and a sliding groove dug near an opening of said axial hole 31, said sliding groove bored with a ball hole for fitting with a steel ball that is correspondingly to be fitted in said restricting ball hole of said main body; and

a positioning device fixed on, said sliding groove of said bar and provided with a restricting knob, a compression spring and a restricting plate, said restricting knob provided with a restricting block located at its bottom side to correspond with said sliding groove so that said restricting knob is able to slide along said sliding groove and press said steel ball to be positioned in one of said restricting ball holes, and a push key formed on an top side of said restricting knob for a user to easily push it to keep said restricting knob sliding along within said sliding groove, said restricting knob also provided with a wing formed at its two curved sides respectively to correspond to said sliding groove, said compression spring installed between said restricting block and said sliding groove and able to push elastically said restricting knob to move back to its original position after pushed away, said restricting plate provided with an elongate opening cut in its central portion to correspond with said sliding groove for fitting with said restricting knob so as to keep said restricting plate fixed at two edges of said sliding groove, and a restricting portion formed at two sides of said elongate opening respectively for pressing on said wings of said restricting knob to let said restricting knob slide along within said sliding groove.

2. A telescopic hand tool as claimed in claim 1, wherein said sliding groove is formed as a two-step ladder for said wings of said restricting knob to attach, said wings further pressed by said restricting portion of said restricting plate to keep said restricting knob sliding restrictively along said sliding groove.

3. A telescopic hand tool as claimed in claim 1, wherein said compression spring is installed in said sliding groove and constrained by said restricting block, keeping one end of said compression spring contacted with said sliding groove and the other one leaned on said restricting block so that said restricting knob can be pushed back to its original position by said compression spring elastically.

4. A telescopic hand tool as claimed in claim 1, wherein said bar is provided with a projection planted longitudinally at two sides of said sliding groove respectively for fitting with a restricting hole bored correspondingly at two sides of said restricting plate to keep said restricting plate fixed on the edge of said sliding groove of said bar.

5. A telescopic hand tool as claimed in claim 1, wherein said sliding groove of said bar is provided with two female-threaded holes bored at its two sides respectively, said restricting plate provided with two through holes bored at its two sides respectively to correspond to said female-threaded holes for screws to pass through to screw fixedly with said female-threaded holes, keeping said restricting plate fixed on the edge of said sliding groove of said bar.

6. A telescopic hand tool as claimed in claim 1, wherein said bar is provided with a grip wrapped around some of its surface.

7. A telescopic hand tool as claimed in claim 1, wherein said restricting knob and said restricting plate are made of metal.

8. A telescopic hand tool as claimed in claim 1, wherein said restricting knob and said restricting plate are made of plastics.

9. A telescopic hand tool as claimed in claim 1, wherein said restricting plate is provided with an arrow mark printed on its outer surface.