Power device for pneumatic packing tool

A power device for a pneumatic packing tool includes a gas delivery unit and a pneumatic unit. The gas delivery unit has an accommodation room, an air inlet, and air outlets. The accommodation room includes a turning block having an input passage. An expansion space is defined between the turning block and the accommodation room. The expansion space communicates with the air outlets. An outer circumferential side of the gas delivery unit is provided with a knob. A push rod is inserted in the knob and the turning block. The pneumatic unit has two through holes. Through the knob, the turning block is turned for the input passage to communicate with one of the through holes to set the direction of winding a belt quickly, and the gas flows from the other through hole to the expansion space to be expanded and exhausted to eliminate the noise.

FIELD OF THE INVENTION

The present invention relates to a power device, and more particularly to a power device for a pneumatic packing tool.

BACKGROUND OF THE INVENTION

A conventional power device for a pneumatic packing tool has a pneumatic motor. The pneumatic motor has an air inlet, an impeller, and an air outlet. When a high-pressure gas is inputted into the air inlet of the pneumatic packing tool, the impeller is brought to rotate and generate a mechanical force for tightening a packing belt so that an article can be packed quickly.

However, during the process of packing, since the pneumatic packing tool is inputted with a high-pressure gas, when the high-pressure gas is exhausted via the air outlet, a large amount of noise will be generated, which will affect the hearing of the user after a long period of time. Therefore, the air outlet is blocked with a fabric, a net or other material to achieve the purpose of noise reduction. But, this way reduces the output efficiency of the pneumatic packing tool. Moreover, the conventional pneumatic packing tool uses a turning valve to change the direction of the rotation of the pneumatic packing tool, which increases the complexity of production and operation. Accordingly, the inventor of the present invention has devoted himself based on his many years of practical experiences to solve these problems.

SUMMARY OF THE INVENTION

The primary object of the present invention is to provide a power device for a pneumatic packing tool, which can reduce the noise in use and change the direction of winding a packing belt.

In order to achieve the aforesaid object, the power device for a pneumatic packing tool of the present invention comprises a gas delivery unit and a pneumatic unit. The gas delivery unit has an accommodation room therein. The gas delivery unit has an air inlet and a plurality of air outlets which are in communication with the accommodation room. The accommodation room is provided with a turning block therein. The turning block has an input passage communicating with the air inlet. An expansion space is defined between the turning block and the accommodation room. The expansion space is in communication with the plurality of air outlets. An outer circumferential side of the gas delivery unit is provided with a knob. A push rod is provided and inserted in the knob and the turning block. The pneumatic unit includes a cylinder. The cylinder has a cylinder chamber therein. The cylinder chamber has two through holes corresponding to the input passage. An impeller is pivotally provided in the cylinder chamber. The impeller includes a rotating shaft. An end of the rotating shaft extends out of the cylinder chamber and has a drive toothed portion.

Thereby, through the knob, the turning block is turned to set the direction of rotation of the impeller and further to set the direction of rotation of the belt winding unit. The gas exhausted from the pneumatic unit expands in the expansion space so that the noise generated by exhaust can be eliminated.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

FIG. 1is a perspective view of the present invention.FIG. 2andFIG. 3are partial exploded views of the present invention. The present invention discloses a power device for a pneumatic packing tool, mounted to a pneumatic packing tool100, and comprises a gas delivery unit10, a pneumatic unit20, and a transmission unit30.

Referring toFIG. 4, the gas delivery unit10has an accommodation room11therein. The gas delivery unit10has an air inlet111and a plurality of air outlets112which are in communication with the accommodation room11. The accommodation room11is provided with a turning block12therein. The turning block12has an input passage121communicating with the air inlet111. An expansion space113is defined between the turning block12and the accommodation room11. The expansion space113is in communication with the plurality of air outlets112. An outer circumferential side of the gas delivery unit10is provided with a knob13. The knob13is adapted to cover the plurality of air outlets112. The knob13has an expansion passage131communicating with the plurality of air outlets112, as shown inFIG. 11. The knob13has a plurality of exhaust holes132communicating with the expansion passage131. A push rod133is provided and inserted in the knob13and the turning block12.

Referring toFIG. 5, the pneumatic unit20includes a cylinder21. The cylinder21is disposed in a casing22. An output passage221is defined between the casing22and the cylinder21, and the output passage221is in communication with the expansion space113, as shown inFIGS. 4-5 and 8-10. The cylinder21has a cylinder chamber211therein. The cylinder chamber211has a circular cross-section. The cylinder chamber211has a first end and a second end each having an opening212. The first end of the cylinder chamber211is provided with a first plate member23. The first plate member23has two through holes231,232corresponding to the input passage121. The top of the inner wall of the cylinder chamber21has two guide recesses213,214corresponding to the two through holes231,232, and the two through holes231,232are in communication with the two guide recesses213,214, respectively. The bottom of the cylinder chamber211has a plurality of perforations215. The perforations215are arranged along the axial direction of the cylinder chamber211and spaced a distance from one another so that the cylinder chamber211can communicate with the output passage221. An impeller24is pivotally provided in the cylinder chamber211. The impeller24includes a rotating shaft241. The axis of the rotating shaft241is arranged eccentrically relative to the axis of the cylinder chamber211. As shown inFIG. 8, the distance from the axis of the rotating shaft241to the top of the cylinder chamber211is less than the distance from the axis of the rotating shaft241to the bottom of the cylinder chamber211. A circumferential side of the rotating shaft241is formed with a plurality of grooves242. The plurality of grooves242are each provided with a blade243. An end of the rotating shaft241extends out of a second plate member25and has a drive toothed portion244. The second plate member25is configured to cover the second end of the cylinder chamber211. The second plate member25has two connecting grooves251beside the rotating shaft241.

Referring toFIG. 6, the transmission unit30has a housing301connected with the casing22of the pneumatic unit20. The housing301is provided with two screws302for locking the pneumatic packing tool100. The two screws302are socket head cap screws. The two screws302are perpendicular to the axis of the transmission unit30, as shown inFIG. 12. The transmission unit30includes a first ring gear31. The inner annular wall of the first ring gear31meshes with a plurality of first planetary gears32. The plurality of first planetary gears32mesh with the drive toothed portion244. The plurality of first planetary gears32are connected to one side of an output gear33. Another side of the output gear33is provided with a driven toothed portion331. The driven toothed portion331meshes with a plurality of second planetary gears34. The plurality of second planetary gears34mesh with the inner annular wall of a second ring gear35. The plurality of second planetary gears34are connected to one side of a worm shaft36. Another side of the worm shaft36is connected to a worm37. A circumferential side of the worm37is connected with one side of a worm gear38, as shown inFIG. 7. Another side of the worm gear38is connected with a belt winding unit39, as shown inFIG. 1.

Referring toFIG. 7, in cooperation withFIGS. 4-6, first, the user sets the knob13and rotates the knob13to turn the turning block12synchronously, such that the input passage121of the turning block12is in communication with the through hole231of the first plate member23and the through hole231is in communication with the expansion space131to set the impeller24to be rotated clockwise. When the input passage121is in communication with the through hole232, the impeller24is rotated counterclockwise. After a packing belt is wound around an article to be packed, the packing belt is inserted through the belt winding unit39. A high-pressure gas is inputted into the air inlet111. A press plate14is pressed, and the gas flows into the pneumatic unit20via the input passage121. At this time, the gas enters the cylinder chamber211through the through hole231and the guide recess213, and the gas pushes the blades243to rotate the impeller24about the rotating shaft241as shown inFIG. 8. The blades243are forced out of the grooves242by gravity and centrifugal forces and against the inner peripheral wall of the cylinder chamber211. As shown inFIGS. 4-5 and 8-10, a portion of the gas flows into the expansion space113from the perforations215through the output passage221while the other portion of the gas flows into the expansion space113from the guide recess214through the through hole232when the gas flows through the bottom of the cylinder chamber211, then the gas flows into the expansion passage131of the knob13via the air outlets112, and finally the gas is exhausted via the plurality of exhaust holes132.

Referring toFIG. 6andFIG. 7, when the impeller24starts rotating, because the first ring gear31is fixed to the housing301and cannot be rotated, the drive toothed portion244of the impeller24drives the plurality of first planetary gears32to rotate simultaneously so that the plurality of first planetary gears32are moved along the inner toothed wall of the first ring gear31, and the output gear33is rotated coaxially with the rotating shaft241of the impeller24. Since the second ring gear35is fixed to the first ring gear31and cannot be rotated, the driven toothed portion331of the output gear33drives the plurality of second planetary gears34to rotate simultaneously so that the plurality of second planetary gears34are moved along the inner toothed wall of the second ring gear35to allow the worm shaft36to start rotating coaxially with the output gear33and to rotate the worm37to drive the worm gear38to turn the belt winding unit39so that the pneumatic packing tool10performs a packing operation.

It is worth mentioning that in the present invention the input passage121of the turning block12is to communicate with the through hole231or the through hole223of the first plate member23through the setting of the knob13, and the other through hole is to communicate with the expansion space131to exhaust the gas so that the direction of the rotation of the impeller24can be quickly set and then the winding direction of the belt winding unit39can be set.

In the present invention, after the gas enters the cylinder chamber211through the guide recess213, it flows to the chamber between two of the blades243to rotate the blades243. The impeller24is rotated at an angle to extend the blades243by gravity and centrifugal forces. Because the axis of the rotating shaft241is eccentrically arranged relative to the axis of the cylinder chamber211, the distance from the axis of the rotating shaft241to the top of the cylinder chamber211is less than the distance from the axis of the rotating shaft241to the bottom of the cylinder chamber211, as shown inFIG. 8, so that the volume between every two of the blades243is not equal to another one, and the gas is expanded in the cylinder chamber211to lower the pressure. A portion of the gas flows into the expansion space113from the perforations215through the output passage221to be expanded again. The other portion of the gas flows into the expansion space113from the guide recess214through the through hole232to be expanded. After that, the gas flows into the expansion passage131of the knob13via the air outlets112to be further expanded. Finally, the expanded gas is exhausted via the plurality of exhaust holes132. Thereby, the pressure of the gas can be reduced by multiple-expansion so that the noise generated by exhaust can be eliminated.

In the present invention, the second plate member25has the two connecting grooves251. When the impeller24is rotated, a small portion of the gas flows to the chamber of another set of the blades to rotate the impeller24smoothly.

In the present invention, one end of the worm shaft36is connected with the plurality of second planetary gears34, and the other end of the worm shaft36is connected with the worm37. Compared to the conventional gearbox which uses a connecting shaft to connect the worm shaft, the present invention has a more direct connection way and reduces the difficulty and failure rate of the production and assembly.

In the present invention, the housing301and the pneumatic packing tool100are fastened with the two screws302. The two screws302are socket head cap screws. The transmission unit30can be effectively positioned by the tapered locking and positioning feature. The two screws302are perpendicular to the axis of the transmission unit30so that the axial stress generated by the worm shaft36won't loosen the two screws302and the transmission unit30will not be retracted.