BACKGROUD ART Conventionally, tools such as a spanner, socket wrench, pipe wrench or the like have been commonly used as a tool for loosening or tightening round members such as a bolt, a nut, a pipe, or the like.

However, in case of using the conventional spanner or pipe wrench in a place with a narrow workspace, the spanner and pipe wrench cannot be rotated at more than a predetermined angle. Thus, the spanner and pipe wrench are problematic in that they requires a repetitive operation in a manner that they must be mounted to a rotary member and rotated at a predetermined angle, then demounted from the round member such as a bolt, a nut, a pipe or the like, and then re-mounted thereto and rotated at a predetermined angle, thereby making the operation difficult and lowering the working speed. In addition, since the socket wrench, which can carry out a continuous rotary operation, has no open inlet ports, it cannot be disposed and used at all in loosening or tightening a union screw or the like of an unopened, continuous pipeline. Furthermore, the spanner or socket wrench is made to be only used for the round member such as the bolt, nut, pipe or the like of a single size, so spanners and socket wrenches or various sizes must be used according to the size of the bolt, nut, pipe or

the like.

DISCLOSURE OF INVENTION It is, therefore, an object of the present invention to provide a cam spanner which can improve working speed by continuously rotating a round member such as a bolt, nut, pipe or the like without re- mounting the working tool thereto, even in a machine room or machinery with a narrow workspace in which a working tool cannot be rotated at more than a predetermined angle, which can be disposed and used easily in loosening or tightening a union screw of an unopened pipeline, and which can improve working efficiency by using a single tool for round members such as bolts, nuts, pipes or the like of various sizes.

To achieve the above object, there is provided a cam spanner according to the present invention, characterized in that: an extended projection is formed at lateral sides of the front of a spanner body, a cam member is hinged or geared to an inner side of one of those projections to be rotatable, and a round member such as a bolt, nut, pipe or the like can be rotated continuously without re-mounting the cam spanner by inserting the round member into a recessed space portion between the inner circumferential

surface of the projection at the lateral sides.

BRIEF DESCRIPTION OF THE DRAWINGS The above objects, features and advantages of the present invention will become more apparent from the following detailed description when taken in conjunction with the accompanying drawings, in which: FIG. 1 is an exploded perspective view of a cam spanner in accordance with the first embodiment of the present invention; FIGs. 2a through 2c are state views illustrating an operation state of the cam spanner in accordance with the first embodiment of the present invention; FIG. 3 is an exploded perspective view of a cam spanner in accordance with the second embodiment of the present invention; FIG. 4 is a state view illustrating an operation state of the cam spanner in accordance with the second embodiment of the present invention; FIG. 5 is an exploded perspective view of a cam spanner in accordance with the third embodiment of the

present invention; and FIG. 6 is a state view illustrating an operation state of the cam spanner in accordance with the third embodiment of the present invention; <Explanation of symbols in the figures> 10: spanner body 12,12': projection 14: operating recess 15: inserting recess 16,27,40,40' : cam member 18,30,54: elastic body 20: cover 22: fixing pin 24: sliding portion 25: path 32: embossed portion 34: connection recess 36: coupling hole 38: wire 42: guide gear portion 46: connecting portion 48: projected track 50: guide hole 52: space portion

100: rotary member BEST MODE FOR CARRYING OUT THE INVENTION As shown in FIGs. 1 through 6, a cam spanner according to the present invention includes: a spanner body 10 of a bar shape for applying a force to rotate a rotary member 100 such as a bolt, a nut, a pipe or the like; projections 12 and 121 for inserting the rotary member 100 which are protruded at lateral sides of the front of the spanner body 10; and cam members 16,27,40 and 40'being provided at an inner side of one of the projections 12 and 12'and rotating the rotary member 100 by applying a force to the spanner body 10 and making the rotary member 100 fixed only in one direction when it is rotated or rotating only the cam spanner in idle by making the rotary member 100 unfixed when it is rotated in the opposite direction.

Preferred embodiments of the present invention will now be described with reference to the accompanying drawings.

[Embodiment 1] FIG. 1 is an exploded perspective view of a cam spanner in accordance with the first embodiment of the present invention.

As illustrated therein, the cam spanner includes projections 12 and 12'rounded in a horn shape being extended and protruded at lateral sides at the front of a spanner body 10, a cam member 16 being hinged to the projection 12 to be rotatable in one direction, an operating recess 14 formed inside the projection 12 and recessed to a predetermined thickness to form a step, and a cover 20 for covering the cam member 16 inserted into the operating recess 14.

The cam member 16 is formed in a rectangular shape and is protruded at a predetermined interval outwardly of the inner circumferential surface of the projection 12, one end of the cam member 16 being passed through a punch hole by a fixing pin 22 and engaged to the operating recess 14 of the projection 12, lateral sides of the cam member 16 being connected by an elastic body 18 fixed to an insertion recess 15 formed at one side of the operating recess 14 and being pulled out to be tightly contacted to the insertion recess 15 by the elastic force of the elastic body 18.

FIGs. 2a through 2c are state views illustrating an operation state of the cam spanner in accordance with the first embodiment of the present invention.

As shown in FIG. 2a, the cam member 16 supports the outer circumferential surface of a rotary member

100. Thus, as shown in FIG. 2b, the rotary member 100 is rotated along with the cam spanner by fixing the rotary member 100 in applying power to the spanner body 10 and rotating it in one direction. For example, if a bolt or nut is used, the rotary member 100 can be tightened by the rotating force by being rotated clockwise at a predetermined interval. In rotating the spanner body 10 in the opposite direction in order to continuously tighten the rotary member 100, as shown in FIG. 2c, only the cam spanner is rotated in idle as the cam member 16 is pushed to one end from the operating recess 14, and the rotary member 100 is not rotated. Next, the cam member 16 is returned to the state of FIG. 2a by the restoring force of the elastic body 18. Then, the rotary member 100 can be tightened or loosened by continuously rotating the rotary member 100 without carrying out the above-described repetitive operation of demounting the cam spanner from the rotary member 100 and re-mounting it thereto.

[Embodiment 2] FIG. 3 is an exploded perspective view of a cam spanner in accordance with a second embodiment of the present invention.

As shown in FIG. 3, a cut out recess 28 is formed at a projection 12 at the front of a spanner body 10, and a cam member 27 is inserted into the cut out

recess 28 and hinged thereto to be rotatable in one direction.

The cam member 27 is formed in a horn shape bent in one direction, is formed with an embossed portion 32 at the outer surface that is bent so that the contact surface with the rotary member 100 cannot be slid well, and is formed with a coupling hole 36 at one side so that it can be coupled and engaged to the projection by a fixing pin 22. Into the coupling hole 36, an elastic body 30, of which one end is fixed to the cam member 27 and the other end is fixed to the projection 12, is inserted for applying an elastic force to the cam member 27.

In addition, at the opposite side of one side at which the coupling hole 36 of the cam member 27 is formed, a connection recess 34 for connecting and fixing a wire 38 is formed. The wire 38 is configured to connect the cam member 27 and a lever 26 of a sliding portion 24 along a path 25 which is passed through by connecting the cut out recess 28 and the sliding portion 24 at the middle of the spanner body 10. The sliding portion 24 is a guide recess for operating the cam member 27 by means of the lever 26, so that the lever 26 can move forward and backward.

FIG. 4 is a state view illustrating an operation state of the cam spanner in accordance with the second

embodiment of the present invention.

When the lever 26 is pulled backward to pull the cam member 27 backward, then the rotary member 100 is inserted between the projections 12 and 12', and then the lever 26 is released, the cam member 27 is returned by the restoring force of the elastic body 30 to thus make the rotary member 100 and the embossed portion 32 of the cam member 27 contacted with each other. In applying power to the spanner body 10 and rotating it in one direction, the rotary member 100 is rotated along with the cam spanner since the rotary member 100 is fixed by the cam member 27. For example, if a bolt or nut is used, the rotary member 100 can be tightened by the rotating force by being rotated clockwise at a predetermined interval. In rotating the spanner body 10 in the opposite direction in order to continuously tighten the rotary member 100, as the force applied to the cam member 27 is released, the cam member 27 does not support the rotary member 100, thereby making the cam spanner rotated in idle and the rotary member 100 not rotated. Next, the cam member 16 is returned to the original state by the restoring force of the elastic body 30. Then, the rotary member 100 can be tightened or loosened by continuously rotating the rotary member 100 without carrying out the above-described repetitive operation of demounting the cam spanner from the rotary member 100 and re-

mounting it thereto. After tightening or loosening the rotary member 100, the cam spanner can be demounted from the rotary member 100, since the cam member 27 is separated from the rotary member 100 by pulling the lever 26 backward.

[Embodiment 3] FIG. 5 is an exploded perspective view of a cam spanner in accordance with a third embodiment of the present invention.

As shown in FIG. 5, the cam spanner includes projections 12 and 12'rounded in a horn shape being extended and protruded at lateral sides of the front of a spanner body 10, an operating recess 14 formed inside the projection 12 and recessed to a predetermined thickness to form a step, and cam members 40 and 40'being inserted into the operating recess 14 covered with a cover 20.

On the inner surface of the operating recess 14, a guide gear portion 42 of an embossed shape is formed.

At the lower end of the operating recess 14, there is punched a guide hole 50, which is rounded according to the shape of the projection 12 at a predetermined width and length.

The cam member 40 and 40'are shaped in a round gear with a hole punched therein and are engaged to the guide gear portion 42 of the operating recess 14,

each of them being positioned at the upper and lower sides of a connecting portion 46 fixed and attached to the end of the wire 38 and being engaged to the guide hole 50 one after another by a fixing pin 22.

The wire 38 is provided at a path 25 that is passed through along the inside of the spanner body by connecting the operating recess 14 and the sliding portion 24. At one end of the wire 38, the connecting portion 46 connected with the cam members 40 and 40' is fixed and attached. The other end thereof is connected to a lever 26 provided at the sliding portion 24. At the middle of the wire 38, a projected track 48 formed in a round band is fixed and attached.

At the middle position of the path 25, a space portion 52 more extended than the path 25 is formed with a predetermined width and length. Into the space portion 52, an elastic body 54 coupled to the wire 38 is inserted, and at the front of the space portion 52, the projected track 48 of the wire 38 is tightly contacted by the elastic body 54.

FIG. 6 is a state view illustrating an operation state of the cam spanner in accordance with the third embodiment of the present invention.

When the lever 26 is pulled backward, the cam members 40 and 40'are engaged with the guide gear portion 42 to be moved backward along the guide hole

50 while being rotated. When the rotary member 100 is inserted between the projections 12 and 12'and the lever 26 is released, the projected track 48 of the wire 38 is moved forward by the elastic force of the elastic body 54 inserted into the space portion 52.

Also, the cam members 40 and 40'are moved forward to be tightly contacted with the outer surface of the rotary member 100 and be fixed by the cam members 40 and 40'. Thus, when the spanner body 10 is rotated in one direction, the rotary member 10 is rotated along with the cam spanner. For example, if a bolt or nut is used, the rotary member 100 can be tightened by the rotating force by being rotated clockwise at a predetermined interval. When the spanner body 10 is rotated in the opposite direction, the cam member 40 tightly contacted with the rotary member 100 is pushed out along the guide gear portion 42. Thus, the rotary member 100 is not fixed and rotated while only the cam spanner is rotated in idle. By such a repetitive operation, the rotary member 100 is loosened or tightened by being rotated continuously. Afterwards, the lever 26 is moved backward to make the cam member 40 separated from the rotary member 100, thereby making the cam spanner demounted naturally from the rotary member 100.

On the contrary to the first through third embodiments, the rotary member 100 can be rotated in

the opposite direction by turning the cam spanner upside down. In addition, rotary members of various sizes can be easily loosened or tightened by means of one cam spanner by adjusting the lever connected with the cam member. Furthermore, the construction of the first through third embodiments can be applied to spanners of various forms such as a monkey spanner, and a plurality of cam members can be disposed at the spanner.

INDUSTRIAL APPICABILITY As described above, also in a machine room or machinery with a narrow workspace in which a working tool cannot be rotated at more than a predetermined angle, a rotary member such as a bolt, nut, pipe or the like can be continuously rotated without re- mounting the working tool thereto, thereby improving working speed. In addition, also in loosening or tightening a union screw of an unopened pipeline, it can be used by easily disposing it between projections of a cam spanner. Furthermore, a single tool can be used for round members such as bolts, nuts, pipes or the like of various sizes, thereby improving working efficiency and reducing working time.