Pick and place head construction

• US 6,145,901 A
• Filed: 03/10/1997
• Issued: 11/14/2000
• Est. Priority Date: 03/11/1996
• Status: Expired due to Fees

• Current Assignee: Rich, Donald S.
• Original Assignee: Rich, Donald S.
• Inventors: Rich, Donald S.
• Primary Examiner(s): Kramer, Dean J.
• Application Number:
  US08/814,299
• Time in Patent Office: 1,345 Days
• Field of Search: 294/2, 294/64.1, 294/65, 294/87.1, 29/743, 29/759, 414/627, 414/737, 414/752, 901/40
• US Class Current: 294/189
• CPC Class Codes: B25J 15/026 actuated by gears
• CPC Class Codes: B25J 15/0616 with vacuum
• CPC Class Codes: H01L 21/67706 Mechanical details, e.g. roller, belt H01L21/67709 takes precedence
• CPC Class Codes: H01L 21/67721 the substrates to be conveyed not being semiconductor wafers or large planar substrates, e.g. chips, lead frames H01L21/6773 takes precedence
• CPC Class Codes: H01L 21/6838 with gripping and holding devices using a vacuum; Bernoulli devices
• CPC Class Codes: H05K 13/0409 Sucking devices
• CPC Class Codes: H05K 13/0413 with orientation of the component while holding it; Drive mechanisms for gripping tools, e.g. lifting, lowering or turning of gripping tools

Abstract

Disclosed is an improved pick and place head construction of a type employed for transporting individual semi-conductor chips and similar articles of manufacture during manufacturing processes, and similar non-manufacturing environments. The disclosed device includes a dual head for engaging the chips as well as improved structure for varying the space between the heads by means of programmable actuators. In one embodiment, the vacuum spindles which reciprocate axially to engage the chips are also capable of axial rotation to enable the engaged chips to be rotated as they are transported to a place location. Also disclosed are improved article engaging members formed of synthetic resinous foam materials to enable effective vacuum engagement of non-planar surfaces. One form provides for simultaneous static dissipation.

Claims

1. In a device for transporting workpieces from a first to a second location by vacuum engagement of a reciprocating spindle, the improvement comprising:

an elongated supporting means;

at least a first vacuum head element supported upon said means, said vacuum head element having a rotary motor having an output shaft;

a helical pinion driven by said shaft, said reciprocating spindle having a helical rack on a surface thereof, said rack meshing with said pinion;

whereby controlled rotation of said motor imparts reciprocating movement of said spindle within predetermined limits.

2. The improvement set forth in claim 1, further comprising a second vacuum head element supported upon said means, whereby a pair of workpieces may be simultaneously engaged and transported between first and second locations.

3. The improvement set forth in claim 2, wherein at least one of said first and second vacuum head elements is slidably adjustable along the axis of said means.

4. The improvement set forth in claim 3, further comprising a pitch adjustment element for varying the distance between the spindles of said first and second head elements.

5. The improvement set forth in claim 4, said pitch adjustment element including a linear driven stepper motor mounted upon said means, said motor having an axis of shiftable motion along said shaft;

and a cam follower surface on at least one of said vacuum head elements;

whereby movement of said stepper motor shaft shifts said vacuum head elements adjustably along said means.

6. The improvement set forth in claim 5, further comprising said second vacuum head slidably carried by said means, a cam having first and second camming surfaces engaging corresponding cam follower surfaces on each of said vacuum head elements to simultaneously shift the position of each vacuum head element, thereby varying the pitch distance between the vacuum spindles of each element.

7. The improvement set forth in claim 6 further comprising resilient means for urging said vacuum head elements in to engagement with said camming surfaces.

8. The improvement in accordance with claim 7, said pitch adjustment element including a mounting bracket, a pair of rectilinear rack members carried in sliding relation by said mounting bracket, each rack coupled to a respective vacuum head element, a rotary motor carried by said mounting bracket having an output shaft, a pinion carried by said shaft, said pinion simultaneously driving each of said rectilinear rack members.

9. The improvement set forth in claim 4, in which said pitch adjustment element comprises a fixed linear rack, a motor carried by one of said first and second vacuum head elements, and a pinion driven by said motor;

said pinion engaging said rack to vary the degree of pitch between said first and second vacuum head elements.

10. The improvement set forth in claim 1 in which said vacuum head element comprises a housing supported by said spindle, said housing having a central bore communicating with a vacuum source connected to said spindle, said housing having a radially-oriented surface defining a free end thereof, and a porous foam member overlying said radially-oriented surface, an outer surface thereof being adapted to engage a surface of an article to be transported.

11. The improvement set forth in claim 1, further comprising a second motor, a second pinion driven by said second motor, a sleeve surrounding said spindle in splined relation thereto, said second pinion engaging said sleeve in geared relation to impart axial rotation of said spindle.

12. In a device for transporting workpieces from a first to a second location by vacuum engagement of a reciprocating spindle, the improvement comprising:

an elongated supporting means;

first and second vacuum head elements supported upon said supporting means, said vacuum head elements each having a rotary motor having an output shaft, a helical pinion driven by said shaft, said reciprocating spindle having a helical rack on a surface thereof, said rack meshing with said pinion;

whereby control rotation of said motor imparts reciprocating movement to said spindle within predetermined limits;

at least one of said first and second vacuum head elements being slidably adjustable along an axis of said supporting means; and

a pitch adjustment element for varying the distance between the spindles of said vacuum head elements, said pitch adjustment element including a mounting bracket, a pair of rectilinear rack members carried in sliding relation by said mounting bracket, each rectilinear rack member being coupled to a respective head element, a rotating motor carried by said mounting bracket having an output shaft, said shaft having a pinion;

said pinion simultaneously driving each of said rectilinear rack members.

13. In a vacuum head element for transporting workpieces from a first to a second location by means of vacuum engagement of a reciprocating spindle, the improvement comprising:

a relatively fixed housing defining an elongated bore, a cylindrical rack carried by said housing within said bore for axial reciprocation therein, a first ball-bearing raceway in an outer surface of said rack, a corresponding raceway in said bore, and ball bearings carried by said raceways;

whereby said ball bearings provide a continuous bearing surface between said housing and said rack, and a keying function to prevent relative axial rotation therebetween; and

a second raceway in each of said bore and said rack, positioned 180 degrees relative to said first raceway and corresponding raceway.

14. The improvement in accordance with claim 13, in which said ball bearings are alternately formed of steel and nylon.

15. The improvement in accordance with claim 13 in which said ball bearings are encased within a synthetic resinous raceway.

16. The improvement in accordance with claim 13, further comprising a motor for driving said rack, said motor being positioned within said housing;

and a thermally conductive compound positioned between said motor and said bearing for transferring heat generated by said motor to said housing to enable said housing to serve as a heat sink.

17. The improvement in accordance with claim 16, said motor having an output shaft, a helical gear on said shaft, and angularly oriented ball bearings for observing thrusts generated by said helical gear.

18. In a device for transporting workpieces from a first to a second location by vacuum engagement of a reciprocating spindle having a vacuum head, the improvement comprising:

a housing supported by said spindle, said housing having a central bore communicating with a vacuum source connected to said spindle, said housing having a radially oriented surface defining a free end thereof, and a porous foam member overlying said radially oriented surface, an outer surface thereof being adapted to engage a surface of an article to be transported, wherein vacuum is drawn through the pores of said porous foam member, and said porous foam member conforms to said surface upon engagement therewith.