[Background] Design [Field Test] [Literature Cited]

Design:

The aquatic rake designs presented are intended to illustrate two possible extremes in rake head designs so that a user might use this (or a similar) design to meet their specific needs. A commercially-available, sturdy, light weight and expandable pole was selected.

The rake was designed and manufactured by Joe Fleming of SDTDC.

Rake pole

The pole is a product manufactured by Unger Window Cleaning Products, which specializes in manufacturing professional cleaning tools.

For the aquatic rake, the 5-section collapsible, telescopic, Unger "Tele--Plus--30-foot" pole was modified. The Tele-Plus pole's original 6 ft sections were cut (using a pipe cutter) to 3 ft sections each. When combined, the 5 interlocking poles can be extended (like a telescope) to a length of 11 ft.

Pipe Cutter

The "off-the shelf" poles, obviously, could be cut to any length.

Rake Pole - collapsed (left) and separated (right)

Rake head

Standard rake head. The standard rake head was designed to have the dimensions of a standard garden rake. It is essentially a 3/16 in. thick, 9 1/4 " x 5" aluminum plate that was machined into a two-sided rake head.

Standard Rake Head Note the 1/16 in. cable wire that runs through the T-bar opening.

A 9 1/4" x 5" aluminum plate was machined to have rake teeth about 1" in length and be 1" apart. (See photos below.) Four 5/16 in. holes were drilled in the plate to accommodate 1/4 inch U-bolts, which were used to attach the manufactured rake to an Unger "T-bar" attachment (see Unger Strip Washer T-bar). (Note: the Unger Ergo Tec® Locking Cone attaches the T-bar to the pole.)

A 3 foot long, 1/16 inch stranded stainless-steel cable wire is attached to T-bar and strung through the hollow rake poles and attached to a standard dog leach. This allows the user to retrieve the rake head should it become detached from the pole.

Rake head - top view (top); bottom and side view (bottom)

Comb rake head. The comb rake head is designed to allow the user to sample small-leaved aquatic vegetation (e.g., duckweed). Two designs are presented: one design with the comb "in-line" with the rake pole (photo below, left) and one design with the comb perpendicular to the rake pole (photo below, right).

The comb is a standard, inexpensive 6 1/4 " long comb readily available from Walmart, Walgreens or Target.

Comb Rake Heads - "in-line" alignment (left) and perpendicular alignment (right).

The "in-line" comb rake alignment simply bonds a comb into a notch cut into one of the standard Unger attachments. (See Unger Cone Adapter) using J-B Weld® or similar epoxy.

The design for the bracket to hold the comb in the perpendicular alignment is shown in the drawing below.

The comb is held in a transverse-mounted bracket. A 3/4" wide x 6.5" long strip holds the comb in place with two 1/4" screws spaced 4.5" apart.

Two holes are drilled through the comb handle where the screws pass through. (Note a center drill #3 works best to prevent comb breakage when drilling holes.)

The bracket is mounted to a T-bar (cut to a length of 6.5" on top) like the standard rake head.

Design for transverse mounted bracket for the perpendicular alignment comb head.

Brackets attached to T-bar w/o comb (front view)	Brackets attached to T-bar w/o comb (side view)
Comb in bracket: Left - bottom view; Right - top view