US 6,032,845 A · Variable pitch tape feeder and pitch selection switch therefor

Abstract

In a variable-pitch tape feeder for feeding parts to a pick and place machine used to produce electronic circuit boards, a switch assembly is provided which controls the limits of a shutter movement and the tape advance distance dependent upon the desired pitch. The tape feeder uses a carrier tape to deliver parts to the pick and place machine. The parts are inserted into depressions at regular intervals along the length of the tape. To accommodate tapes of varying pitches, i.e., distances between parts, the feeder uses an electronic control unit to drive the tape feed mechanism and actuate a shutter. The shutter prevents small parts from escaping their respective depressions prematurely. The switch provides a stop surface which limits the rearward travel of the shutter and a flag which is detected by optical sensors to determine the position of the switch and thus the pitch desired by the operator. By limiting the rearward travel of the shutter, especially when using small-pitch parts, parts subsequent to the one positioned at the pick-up point will be prevented from escaping their respective recesses in the carrier tape. A control unit electronically advances the carrier tape the desired distance according to the position of the switch.

Claims19

Dependent claims

A pitch switch assembly for a variable pitch carrier tape feeder of the type that periodically advances the carrier tape to sequentially position at a pick-up location each of a series of parts contained in regularly-spaced recesses in a carrier tape, comprising:

a cover assembly for covering a carrier tape having an opening at the pickup location to provide access to a part contained by said carrier tape by a pick and place machine;
a shutter slidably supported by said cover assembly and variably occluding said opening;
and
a switch accessible and repositionable by an operator to select a desired pitch, the switch comprising:
control means for defining a retracted position of said shutter which varies with the desired pitch, said shutter being in said retracted position when positioned over at least one adjacent part which immediately follows a part positioned at the pickup location without hindering access to the part at the pickup location, and
means for providing an indication to a control unit of a desired pitch so that said control unit can advance the carrier tape the correct distance during each advance operation performed by the carrier tape feeder.

3 more elements

A method of configuring a variable pitch carrier tape feeder of the type that sequentially positions at a pick-up location each of a series of parts contained in regularly spaced recesses in a carrier tape to deliver a carrier tape at a desired pitch, comprising:

covering a carrier tape along a length of a carrier tape from a point adjacent to that which a cover strip is removed from the carrier tape to an opening at said pick-up location;
slidably supporting a shutter to variably and partially occlude said opening;
mechanically controlling the shutter so that, when the carrier tape is not being advanced, it is positioned at a retracted position which varies with desired pitch, the shutter being in a retracted position when positioned over at least one adjacent part which immediately follows a part positioned at the pickup location without hindering access to the part at the pickup location;
and
providing an indication to an electronic control unit of the desired pitch so that said control unit can advance the carrier tape the correct distance during each advance operation performed by the carrier tape feeder;
said step of mechanically controlling the shutter and the step of providing an indication are both performed by positioning a pitch switch to the desired pitch.

3 more elements

A variable pitch tape feeder, comprising

a carrier tape reel support for supporting carrier tape having any one of several predetermined pitches;
a carrier tape guide for guiding said carrier tape from said reel to a cover strip removal location then a pick-up location;
a feed sprocket for engaging feed-holes regularly spaced along the length of carrier tape for advancing said carrier tape through said tape guide;
a motor for driving said feed sprocket;
a control unit for controlling said motor;
a cover assembly covering said carrier tape from said cover strip removal location to a location past said pick-up location, said cover assembly having an opening at said pickup location;
a shutter slidably mounted to said cover assembly at least partially occluding said opening when positioned in a forward position;
a pitch switch repositionable by an operator having several positions corresponding to said several predetermined pitches, a stop surface limiting rearward travel of said shutter, said stop surface defining a retracted position of said shutter which varies with the position of the pitch switch;
and
a sensor detecting the position of the pitch switch and providing a pitch input signal to said control unit, said control unit advancing the carrier tape a distance according to said pitch input.

7 more elements

Dependencies are inferred from the claim text.

Variable pitch tape feeder and pitch selection switch therefor

Life of this patent

Variable pitch tape feeder and pitch selection switch therefor

Life of this patent

Abstract

Claims19