Automatic dotting machine for manufacture of heat sink for electronic component

An automatic dotting machine (100) includes a feeding device (10) for unloading workpieces (200) one by one with the same interval, a conveying device (40) for conveying the workpieces to a predetermined dotting region, a sensor unit (70, 251) for detecting whether the workpieces reach the predetermined dotting region, a programmed control unit (30) for controlling the whole process of the dotting and receiving signal detected by the sensor unit and then sending out a command, a sliding device for moving the workpieces to a predetermined dotting position after receiving the command of the programmed control unit, a positioning device for clamping and positioning the wokpieces to the predetermined position to be dotted, and a punching device (24) for punching dents on the workpieces after the workpieces are positioned at the predetermined position.

FIELD OF THE INVENTION

The present invention relates to an automatic dotting machine, and particularly to an automatic dotting machine suitable for performing punching dots in a workpiece in a programmable manner, wherein the workpiece is to be used as a part of a heat dissipation device for electronic component.

DESCRIPTION OF RELATED ART

During the machining process, holes are usually required to be formed in a workpiece. However the hole forming process is boring and inaccurate. It needs not only drawing crossed lines in a predetermined position for forming the hole but also making a depression by dotting a crossed point of the crossed lines for facilitating an accurate forming of the hole at the required position.

The operation of the dotting has a relatively low efficiency since it is generally most done by manual hand.

SUMMARY OF INVENTION

According to a preferred embodiment of the present invention, an automatic dotting machine comprises a feeding device for unloading workpieces one by one with the same interval, a conveying device for conveying the workpieces to a predetermined dotting region, a sensor unit for detecting whether the workpieces reach the predetermined dotting region, a programmed control unit for controlling the whole process of the dotting and receiving signal detected by the sensor unit and then sending out a command, a sliding device for moving the workpieces to a predetermined dotting position after receiving the command of the programmed control unit, a positioning device for clamping and positioning the wokpieces to the predetermined position to be dotted, and a punching device for punching dents on the workpieces after the workpieces are positioned at the predetermined position.

DETAILED DESCRIPTION

With reference toFIG. 1, there is generally indicated an automatic dotting machine100for dotting a plurality of dents in each of a plurality of workpieces200which herein have been shown as being a flat metal plates according to the invention. The workpieces200are used as bases for construction of heat sinks for dissipating heat generated by electronic components. In practice, the workpieces200are used to thermally contact with the electronic components and bear fins thereon. The dotting machine100comprises a rectangular bed60having support uprights63, a conveying device40mounted on the bed60for receiving and conveying the workpieces200to a predetermined dotting region, an automatic feeding device10for unloading the workpieces200at the same intervals to the conveying device40, a working apparatus20for dotting the workpiece200, a programmed control unit30for controlling the whole dotting process and a hydraulic actuator50for providing the working apparatus20with required driving force. The whole process for dotting one of the workpieces200only spends two seconds, according to the invention. Such a cycle time is considered quit efficient, in comparison with the conventional art.

Also referring toFIG. 2, the conveying device40includes a pair of pulleys44,45mounted on tow opposite ends of the bed60, respectively. The pulleys44,45include shafts42,43, respectively. An endless belt46is mounted on the pulleys44,45, for receiving each workpiece200falling from the feeding device10and for conveying the fallen workpiece200to the predetermined dotting region. A pair of supporting brackets61,62is mounted on the bed60, for supporting the belt46. A motor48and a gear box47linked to the motor48are mounted under the bed60for driving the shafts43to rotate, whereby the pulleys44,45and the shaft42rotate together. An upper layer of the belt46runs from the pulley44to the pulley45above the motor48to convey the workpiece200from the feeding device10to the predetermined dotting region.

Also referring toFIGS. 3-5, the feeding device10is broadly described as comprising a mounting plate11mounted onto the bed60. The plate11is positioned between the pulley44and the supporting bracket61. A rectangular feed box12is vertically mounted on the plate11for receiving the workpieces200therein. The feed box12has an upper opening124for putting the workpieces200therein, and a lower opening126for unloading the workpieces200therefrom. Each workpiece200has a same thickness. The belt46is below the lower opening126for receiving the workpieces200unloaded from the lower opening126of the feed box12. The feed box12has a pair of symmetrical lateral walls120,122. Each wall120,122defines a notch1200,1220therein. A vertical distance between the two notches1200,1220is equal to the thickness of two workpieces200. A supporting cylinder14is positioned at a left side of the lateral wall120. The cylinder14has a slide piston rod140connected to a controllable supporting plate142. The supporting plate142contacts a first workpiece200in a bottom-up direction of the feed box12. The supporting plate142extends through the feed box12from the notch1200and abuts against an inner surface of the lateral wall122, for supporting the workpieces200thereon. The supporting plate142is drawn by the piston rod140of the cylinder14out of the feed box12under a command of the programmed control unit30when the feeding device10works. A clamping cylinder16is positioned at a right side of the lateral wall122via a positioning block160. The cylinder16has a slide piston rod (not shown) connected to a controllable bar162. The piston rod of the cylinder16may push the bar162to extend through the notch1220and abut against a side of a second workpiece200pointed in the bottom-up direction under a command of the programmed control unit30. Referring toFIG. 5, when the feeding device10works, the bar162firmly abuts against the second workpiece200, whereby the bar162and an inner surface of the lateral wall120firmly clasp the second workpiece200, and the other workpieces200on the second workpiece200are supported by the second workpiece200. Meanwhile the supporting plate142is drawn out of the feed box12, whereby the first workpiece200is dropped on the belt46from the lower opening126of the feed box12because of the effect of gravity. Referring toFIG. 4, once the first workpiece200is dropped, the supporting plate142is pushed backed by the piston rod140of the cylinder14to extend through the feed box12and abut against the inner surface of the lateral wall122. Simultaneously, the bar162is drawn from the notch1220and is separated from the second workpiece200such that the remainder workpieces200are dropped on the supporting plate142because of the effect of gravity. The workpiece200hereinafter means the first workpiece200prepared to be dotted.

Please referring toFIG.1andFIG. 6, the working apparatus20is mounted on the bed60and positioned between the two supporting brackets61,62via two boards21,27which are linked together. The working apparatus20comprises a positioning device (not labeled). The positioning device comprises a pair of L-shaped templates23symmetrically and respectively located at flanks (not labeled) of the belt46, and a baffling plate25mounted on front ends of the templates23. The baffling plate25interconnects tops of the front ends of the templates23. There is a distance between bottoms of the templates23and a bottom of the baffling plate25such that the belt46extends through a space defined between the templates23and below the baffling plate25. A pair of L-shaped guide plates22is symmetrically and respectively located at the flanks of the belt46and adjacent to back ends of the templates23, for guiding the workpiece200to a region of the positioning device. There is a space between the back end of the template23and a front end of the guide plates22, for mounting a sensor70therein. When the workpiece200unloaded from the feed box12moves through the sensor70, the sensor70gives a signal to the programmed control unit30and the feed box12begins to work to release the workpieces200in sequence, under control of the programmed control unit30.

Please referring toFIG. 8, each template23is mounted onto the board21via a pair of screws234. The template23has a top portion230protruding from an inner surface thereof. A depression232is formed at the front end of the template23, for mounting the baffling plate25thereon. The template23defines a pair of horizontal through holes231at external lateral side thereof. The baffling plate25connects with a pair of posts252. The posts252each have a free end forming external threads253. A pair of cylinders250is located below the board27. The cylinder250has a piston rod254. The posts252extend through the boards21,27and threadedly engage with the piston rods254, respectively. The baffling plate25can slide up and down along a straight line via the extension and retraction of the piston rods254of the cylinders250. A sensor251is mounted on the baffling plate25.

Please referring toFIG. 7, the working apparatus20further comprises a punching device24. The punching device24comprises a pair of punching holders249symmetrically and respectively located the left and right sides of the templates23. Each punching holder249forms a pair of guide blocks245at end edges of opposite front and back sides thereof, respectively. The punching holder249comprises a pair of spaced punches242, facing to the template23. The punch242is used for extending through the through hole231and punching a dent on a lateral side of the workpiece200. The punch242has a taper head241for conveniently dotting the workpiece200. The punching holder249defines a threaded hole247, opposite to the punch242. A hydraulic cylinder248is connected to the punching holder249, for providing hydraulic force to the punching device24. The hydraulic actuator50provides hydraulic fluid to the hydraulic cylinder248. The hydraulic cylinder248is fixed to the board21via a fixer240. The hydraulic cylinder248has a piston rod246extending through the fixer240and threadedly engaging with the threaded hole247of the punching holder249. The piston rod246pushes the punching holder249to slide along the left-right direction. A pair of punching fixers243is mounted on the boards21,27via screws (not labeled), and is positioned beside front and back sides of each punching holder249, respectively. Each punching fixer243defines a groove244corresponding to the guide block245. When the punching holder249moves by push of the piston rod246, the guide block245slides along the groove244of the punching fixer243for performing the dotting to the workpiece200.

Please again referring toFIG. 8, the working apparatus20further comprises a sliding device26mounted between the two templates23, for lifting the workpiece200to the predetermined position to be dotted. The sliding device26comprises a retainer plate260positioned between the two templates23, a pair of symmetrical lock bocks262mounted on the retainer plate260, a pair of sliding blocks264abutting against back ends of the lock blocks262, and a back plate265below the board27. The two lock blocks262are positioned at the flanks of the belt46, respectively. The lock blocks262have back ends abutting against the sliding blocks264, and front ends abutting against the baffling plate25. Each lock block262has an L-shaped configuration, and comprises a horizontal plate2621and a vertical plate2622. The vertical plate2622has a top surface below a top surface of the sliding block264. The belt46runs over the horizontal plate2621. The workpiece200is conveyed on top surfaces of the two vertical plates2622of the two lock blocks262via the belt46. Each sliding block264is slidably positioned on the retainer plate260at the back end of the lock block262such that the sliding blocks264are adjustable to always abut a back end of the workpiece200when the workpiece200is conveyed to the top surfaces of the vertical plates2622for being dotted. The back plate265forms three posts263having internal threads. Tree screws261extend through the retainer plate260and the boards21,27to threadedly engage with the posts263, whereby the retainer plate260connects with the back plate265. Two cylinders266are positioned below the back plate265. Each cylinder266has four shanks267having external threads. The shanks267engage in threaded holes270of the board27so as to fix the cylinders266to the board27. Two shanks267of each cylinder266extend through the back plate265to enable the back plate265to move up and down relative to the shanks267. Each cylinder266connects a piston rod (not shown) at central portion thereof to push the back plate265to move. The movable back plate265drives the whole sliding device26to move straightly upwards and downwards, thereby lifting the workpiece200to the predetermined position to be dotted.

With reference toFIGS. 1,4-5, and9-11, the dotting machine20begins to work by turning power on. The belt46is driven by the motor48and the gear box47. The first workpiece200is unloaded from the feeding device10by a command of the programmed control unit30. Once the unloaded first workpiece200runs between the guide plates22and the templates23, the sensor70gives out a signal to the programmed control unit30, and the feeding device10begins next cycle work and next workpiece200is unloaded therefrom via a command of the programmed control unit30. Thus, the feeding device10unloads the workpieces200with the same interval to the belt46, which then conveys the wokpieces200to the predetermined dotting region. When the workpiece200runs to the baffling plate23and touch the baffling plate23, the sensor251gives out a signal to the programmed control unit30, and the cylinders266push the sliding device26to move upwardly until the workpiece200abuts against the top portions230of the templates23and separates from the belt46. Simultaneously, the heads241of the punches242of the punching devices24extend from the through holes231of the templates23and dot dents to corresponding positions of the workpiece200. After dotting, the punches242of the punching devices24are withdrawn from the workpiece200, and the sliding device26moves downwardly to the original position to enable the workpiece200to fall to the belt46. Meanwhile, the baffling plate25is controlled to move upwardly by the cylinders250such that there is enough space between the workpiece200and a bottom surface of the baffling plate25to enable the workpiece200fallen to the belt46to travel through the space below the baffling plate25. After the pass of the workpiece200, the baffling plate25returns to the original position and contacts with the templates23. The workpiece200runs toward the pulley45and falls down from the belt46. A slantwise plate (not shown) may be mounted on the bed60, adjacent to the pulley45such that the wokpiece200falls along the slantwise plate to a predetermined position.