Tack pin installation press

An automated press feeds a string of tack pins loaded on a reel. The press shears the part from the string of fasteners and delivers each part individually to a punch for installation. The string of fasteners is pulled from the reel by a sprocket which includes peripheral teeth for engaging the fasteners and for feeding them in a vertical column to a shear station. A horizontally reciprocal shear block severs individual fasteners one-at-a-time from the end of the fastener string at the shear station, each fastener being indexed to the next shear position by incremental rotation of the sprocket. The punch includes vacuum retaining means for lifting each fastener from the shear block.

FIELD OF THE INVENTION

The present invention relates to a fastener installation press. More specifically, it relates to a press for installing miniature clinch pins which deform a work piece panel to achieve affixation by clinch attachment and most specifically, it relates to a reel feed automated fastener installation press for such pins.

BACKGROUND OF THE INVENTION

Clinch-type fasteners are well known in the art for securing panels together face-to-face. A displacer on the shank of the pin deforms material of the bottom panel pushing it into an undercut in the shank thus locking the pin into the bottom panel holding the top panel against it by the head of the pin. A head of the fastener abuts the top sheet and retains it against a bottom panel when the fastener is pressed in.

A problem exists however when handling clinch-type tack pins which are in miniature because they are difficult to handle when one attempts to manually place them into position for a press-in attachment process. As tack pins are being designed and used ever smaller, the automatic orientation feeding installation of these parts becomes even more difficult and sometimes impossible with some very small parts. Therefore, there is a need in the art for a automated installation press for installing clinch-type miniature tack pins which is efficient, effective and economical to use.

SUMMARY OF THE INVENTION

In accordance with one embodiment of the present invention, reeled tack pins are packaged on a standard size reel that can be loaded into an automated press that both shears a part from a string of co-joined fasteners and delivers each part individually to a vacuum or other type of punch for installation. Fasteners manufactured in a continuous string that can be utilized with the present installation press are shown inFIG. 2.

In order to meet the needs in the art, the automated press embodying the invention employs two electrically actuated cylinders and a servo or stepper motor to deliver and install the tack pins. The pins are pulled off the storage reel one at a time by a sprocket driven by a servo or stepper motor. Each part at the end of the string is driven into a shear block. With a part resting in a holding well in the shear block, the shear cylinder actuates, which both shears off a part from the end of the string and delivers the part to the tip of a vacuum punch. The punch then picks the part from the shear block holder, after which the shear cylinder retracts the shear block to accept another pin. With a pin retained on the end of the punch, the punch cylinder actuates to press the part into the assembly waiting below it.

More specifically, one embodiment of the present automated reel feed press comprises a framework having a platform which holds an anvil for supporting a work piece. The framework also holds a punch located in axial alignment above the anvil and is reciprocal between retracted and extended positions. The press further includes a fastener feeding mechanism for delivering a plurality of fasteners one at a time to a position between the punch and the anvil. The feeding mechanism comprises a reel holding an elongate string of co-joined fasteners wound about the reel, the fasteners being contiguously connected toe-to-head thus forming the string. The individual fasteners are severable from the string at junctions between each fastener. The string of fasteners is pulled from the reel by a sprocket which includes peripheral teeth for engaging the fasteners and for feeding them in a vertical column to a shearing station. A reciprocal shear block severs individual fasteners one at a time from a delivery end of the fastener string, each fastener being indexed into the next shear position by incremental rotation of the sprocket. The shear block includes a well for holding each fastener and is reciprocal from a shear position to a delivery position in the axial path of the punch. The punch includes vacuum retaining means for lifting each fastener from the shear block. After the shear block retracts, the punch then extends downward and forcibly drives the fastener into the work piece.

As such, those skilled in the art will appreciate that the conception, upon which this disclosure is based, may readily be utilized as a basis for the designing of other structures, methods, and systems for carrying out the several purposes of the present invention.

DESCRIPTION OF THE PREFERRED EMBODIMENT

Referring now toFIG. 1, the pin reel auto-feed press of the invention is shown. The basic components of the invention include a punch mechanism with a driving cylinder9and a punch11with a vacuum tip. The punch is located directly above in an axial alignment with anvil13. The anvil is supported on a platform15that is carried by framework members17which form the legs of a stand for supporting the components of the press. As will be further described herein, the press comprises a delivery feed mechanism19that includes a reel21and a horizontally reciprocal shear block23assembly.

FIG. 2shows four different types of fasteners manufactured in continuous strings of tack pins. Each string is composed of individual fasteners joined toe-to-head with severable joints between each fastener. In this way, the fastener delivery system requires no carrier medium and creates no scrap.

Referring now toFIGS. 3 and 4, the press is depicted in cross-section. The pin storage reel21supports an elongate string of fastener pins wound about it. An idler wheel27directs the string25into vertical alignment directly above the edge of feed sprocket29. The feed sprocket cooperates with a feed plate31that has a bore which holds the fastener string in a vertical linear column and in engagement with teeth on the feed sprocket. A shear cylinder33moves the shear block35in reciprocal motion horizontally from a shear position directly beneath the columnated string to a position in the axial path of a vacuum punch11at the top of its stroke. The punch is reciprocally moved up and down above the anvil by the punch cylinder9. This arrangement of structures is depicted more closely inFIG. 4. The fasteners are incrementally driven into a holder of the shear block by the sprocket29. The holder provides a stop to the advancement of the fastener string and ensures precise shearing location of each fastener as it is delivered to the shear station.

Referring now toFIG. 5, the sprocket29engages the edges of the fasteners between peripheral teeth37on the sprocket. The individual fasteners are moved to the shear station at a shear position shown inFIG. 4of the holder well in the shear block by the incremental advancement of the rotating sprocket29. Bore39in feed plate31holds the fastener string against the sprocket and in a vertical column directly above the shear block holder at its retracted position.

As sequentially shown inFIGS. 6-9following the numbering of like elements in the previous figures of drawing, individual fasteners40are carried from the shear position shown inFIG. 4by the shear block35to a delivery position adjacent a tip of the vacuum punch11as shown inFIG. 7. By the aerodynamic force of the vacuum punch11provided by drawing a vacuum through air conduit41and retraction of the punch, each sheared fastener40is lifted from the holding well42in the shear block and retained on the tip of the punch. The shear block is then retracted to the shear station38to receive the next fastener from the end of the fastener string25as shown inFIG. 8. As shown inFIG. 9, the punch then is moved downward so that the fastener is forcibly driven into work pieces43positioned against the anvil13. The work pieces being assembled are positioned by an X/Y table (not shown) from installation hole to installation hole as each pin is installed.