Clamping device

1. A clamping device, comprising a clamp assembly and an adjustment assembly, the clamp assembly comprising two symmetrical clamp arms which are oppositely hinged to each other, each of the clamp arms including two identical and parallel clamp pieces, and a jaw, the jaw being detachably connected between the two clamp pieces, the clamping device being characterized in that:

a lower edge of the jaw includes, in order from a left to a right thereof, a first arc-shaped section, a second arc-shaped section and a horizontal section, bottoms of the first arc-shaped section, the second arc-shaped section and the horizontal section are at a same plane, the first and second arc-shaped sections are symmetrical to each other, an angle is defined between the first and second arc-shaped sections, a V-shaped groove is defined between the second arc-shaped section and the horizontal section, and the first and second arc-shaped sections are each longer than the horizontal section;

an elongated pin hole which is arranged in an inclined manner is formed at a left end of the jaw, two ends of the elongated pin hole are in a shape of a semicircle, and a pin hole is formed at a right end of the jaw, the two clamp pieces are provided with clamp-piece pin holes, the left and right ends of the jaw are connected to the clamp pieces by round pins, the round pin at the right end of the jaw is inserted in the elongated pin hole, so that the jaw is rotatable, and a rotation of the jaw is restricted by a relative displacement between the round pin and the elongated pin hole.

2. The clamping device as claimed in claim 1 , wherein the second arc-shaped section and the horizontal section are each provided with a toothed surface.

3. The clamping device as claimed in claim 2 , wherein each of the clamp arms further includes a fixing rod fixed between the two clamp pieces, the adjustment assembly includes a bolt, a nut and a spring, the bolt inserts upwards through the fixing rods on the two clamp arms and then has a top end screwed with the nut, and the spring is sleeved onto the bolt and located between the fixing rods on the two clamp arms.

4. The clamping device as claimed in claim 3 , wherein the bolt is provided with a stop block at a lower end thereof.

5. The clamping device as claimed in claim 1 , wherein a threaded hole of ⅜ inch and a threaded hole of ¼ inch are formed at a top end surface of the jaw.

6. The clamping device as claimed in claim 5 , wherein each of the clamp arms further includes a fixing rod fixed between the two clamp pieces, the adjustment assembly includes a bolt, a nut and a spring, the bolt inserts upwards through the fixing rods on the two clamp arms and then has a top end screwed with the nut, and the spring is sleeved onto the bolt and located between the fixing rods on the two clamp arms.

7. The clamping device as claimed in claim 6 , wherein the bolt is provided with a stop block at a lower end thereof.

8. The clamping device as claimed in claim 1 , wherein each of the clamp arms further includes a fixing rod fixed between the two clamp pieces, the adjustment assembly includes a bolt, a nut and a spring, the bolt inserts upwards through the fixing rods on the two clamp arms and then has a top end screwed with the nut, and the spring is sleeved onto the bolt and located between the fixing rods on the two clamp arms.

9. The clamping device as claimed in claim 8 , wherein the bolt is provided with a stop block at a lower end thereof.

10. The clamping device as claimed in claim 1 , wherein each of the clamp arms further includes a fixing rod fixed between the two clamp pieces, the adjustment assembly includes a bolt, a nut and a spring, the bolt inserts upwards through the fixing rods on the two clamp arms and then has a top end screwed with the nut, and the spring is sleeved onto the bolt and located between the fixing rods on the two clamp arms.

11. The clamping device as claimed in claim 10 , wherein the bolt is provided with a stop block at a lower end thereof.