Manual Rivet Dispenser


Requested Project

Purpose: dispense 1/2" rivets from the device just a few at a time.  Possibly operated by a lever similar to the turntable jig recently constructed for us.

Goal: to help people with limited fine motor skills to participate in a contract that places rivets in holes of metal bars.

Dimensions: small enough to fit on wheelchair trays

4/1/03:  We have a request for one more rivet dispenser identical to the one Russ S. completed for us earlier this year. We have another set of consumers who could benefit from this in a different area of the facility.

Design Notes

A second prototype with improved construction over the first has been built and demonstrated for Option of Lynn County.  It is made up of a 9 inch steel cake pan about 1 1/2 inches deep that is mounted on a bearing such that the cake pan is oriented vertically and can spin about the bearing.  A front cover made of plexiglass is provided that has a 4 inch diameter opening in the middle to accommodate a collector chute for the rivets that are delivered.  Rivets are contained in the lower portion of the drum (cake pan) in the enclosed volume between the boundaries of the cake pan and the cover. As the drum (cake pan) is rotated about the bearing, eight paddles made of 1/4" plexiglass mounted to this front cover pick up a small number of rivets and with continued rotation drop them into a collector chute where they slide out to a work surface for use.  The paddles are mounted such that they nest with the inside diameter of the cake pan when the cover is secured to the pan.   These paddles are mounted so the upper side of the paddle forms an angle of 22.5 degrees to a radius of the cover which tends to cause a small number of rivets to nest on the paddle and lodge against the inner diameter of the pan.  The upper surface of the paddle is also angled at 15 degrees toward the cover so that any rivet lying on the paddle is cradled against the cover by this angle. The paddles are sawed on a radial arm saw from 1/4" plexiglas.  Paddles are secured to the cover with double-sided adhesive tape and one machine screw. A drawing of the part is available. Each paddle will typically deliver one or two rivets, but occasionally deliver 0 or 3 rivets.   The assembly is mounted to a pine board about 10 inches long and 7 1/4 inches wide.  The drum support is provided by a right angle bracket made from a 12 inch by 1 1/8 inch mending brace available from hardware stores.  It is initially a flat strip about 5/32 inch thick having 6 holes on 2 1/4 inch centers.  The bracket is bent to leave two holes for securing the bracket to the board with screws, and providing a hole in the upright section that mounts the bearing shaft about 6 inches off the board.  The bearing shaft is a shoulder bolt 1/2 inch in diameter and having a shoulder length of about 1 1/4 inches. The remaining length of the bolt is provided with 3/8" x 16 threads. The support bearing attached to the drum is a steel cylinder brazed to a flange washer and having a bronze sleeve bearing pressed into the cylinder.  I am recommending that future models replace this support bearing with a hardwood cylinder approximately 2 inches in diameter and about 1 1/4 inches long.  The support bearing is secured to the cake pan with 4 screws.  The shoulder bolt bearing is bolted solidly to the bracket that mounts the assembly to the board, such that the head of this bolt inside the drum represents a stable mounting surface for the rivet chute that collects the dropped rivets and channels them out of the drum.  Thus the head end of the shoulder bolt is center drilled and tapped for a 1/4" X20 bolt to secure the chute.  The rivet chute has a number of complex bends and a template with bend lines and angles is being prepared that can be used to lay it out on a flat sheet of 1/32" aluminum.  In the prototype, the front plexiglass cover is secured to the cake pan by a "C" shaped clamp band, hand formed from 1/32" aluminum sheet stock.  This is a time consuming part to fabricate and if additional models are built I recommend fabricating clamp brackets that can be secured with screws to replace the band clamp.  Finally, to provide a good grip for the client to rotate the cylinder, 4 replacement type pot lid knobs about 5/8" in diameter and 1 1/4" long are equally spaced around the periphery of the front cover and secured by machine screws. Pictures of the prototype are available along with sketches of the assembly, templates for the rivet chute and drawings for the paddles.

9/10/03:  Copy of earlier design that was delivered with minor changes to make it easier to build. Drawings for the original design have been updated to reflect these changes. The second rivet dispenser has been delivered to options and the project is complete.

RCRV designer is Russell Schuchmann, and was requested by Options-Wayne Clayton/Jeannie Sampica. The project was begun Nov 19, 2002 and completed Feb 4, 2003.

              


Additional Information:

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Construction drawings
Motorized rivet dispenser project

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