The history of the making of paper chains out of gum wrappers goes back to the late nineteenth century. Children without gum wrappers, used homework paper or whatever other paper was available to cut or tear paper into the paper rectangles to make paper chains. Today, casual survey suggests that paper chum making is becoming history, while new craft type toys are a fast growing market. Paper chain making is done by hand, folding paper rectangles into quarters to obtain a four-ply strip and folding said four-ply strip into quarters, forming a paper chain link. While quartering is a natural way to facilitate folding, it allows a variety of cutting and folding errors that weaken the chains and makes assembly tedious and difficult. The introduction of a device with the utility to make paper chain making easier and accessible to a wider age group of children would seem to be worth while and timely.
The length to width ratio of paper rectangles determines link assembly clearance and ease of assembly. However, calculation of final assembly clearance is not effective as estimated clearance can be reduced by as much as 70%. Typical cutting and folding variations as well as shape factors must be controlled, to allow the final assembly clearance for ease of assembly. Excessive final clearance, weakens the paper chain, while too little final clearance makes assembly difficult.
Used copy paper (8.5×11 sheets) provides an ample supply of paper rectangles (14 per sheet, 1.57×4:25 inches). Paper rectangles are folded into a four-ply strips, and then in similar procedure said strips are folded into four segments. The result is an interlocking V-shaped paper chain link with two inward folded legs.
U.S. Pat. No. 6,006,513 describes paper chain making, and references the difficulties in making four-ply paper chains. Said patent claims improvement over paper chain making by use of a synthetic strip, cut and folded by machine. While this facilitates chain making using the general shape of the interlocking paper chain link, it is a departure from the craft of hand making paper chains, and enters the fields of interlocking chain links and materials other than paper. Repeatable quality in making paper chain links is essential for ease in assembly. The challenge remained to minimize the difficulties in making and assembling paper chain links in the field of craft toys.
My development process began with the challenge to improve hand crafting of four-ply paper chains. An unexpected result of moving the crease lines outside the quarter points of the four-ply paper chain was the introduction of multiple ply options. The inventive question was, “what happens if we reduce the outer segments for maximum clearance?” The tour-ply chain link becomes (we-ply. Eliminating one outer segment would create a three ply chain link. This would be relevant if two-ply or three-ply chains have increased, or different utility.
The development of tools for making more precise paper chain links has brought the possibility of presenting “The Paper Chain Factory Thy” as a salable product, opening the door for a range of associated craft products such as precut and multicolor rectangles and perhaps a device for cutting a range of rectangles.
With the availability of 8.5 by 11 inch sheets of paper as a source, a three-ply strip offers 16 rather than 14 paper rectangles. The three-ply paper chain is more flexible and with about the same link size as the four-ply strip. A two-ply paper chain is even more flexible and offers 22 paper chain rectangles per sheet. This assumes all three options use 4.25 inch long paper rectangles.
Forcing, two four-ply legs into a “V” shaped inner space to Form a chain link creates shape error that impacts ease of assembly. Forcing two two-ply legs into a “V” shaped inner space creates substantially less shape error. The result is that two-ply strips offers 57 percent more chain links, tighter chains and less distortion than in four-ply chains. With less bulk, assembly is easier. Applications such as jewelry are suited to four-ply chains, whereas surface decorative applications are better served with two-ply chains.
My invention is a craft toy for children which emphasizes the child-made aspect and addresses said difficulties by facilitating the making, of more precise paper chain links. The first difficulty issue involves making the positions of the folds more precise and repeatable. A part of this issue is the making of sharp creases that prevent folds from wandering out of parallel on folding. The second difficulty issue is the elimination of fold interference between the outer leg segment(s) of both the paper rectangle and the strip.
Hand folding practice places the crease lines at the quarter points of both the paper rectangle and the four-ply strip. My invention places the crease line of the outer leg segment(s) of the paper rectangle and the strip outside the quarter points to provide fold clearance.
Because reducing the width of the outer segment(s) of the paper rectangle and strip are adjustments to a single piece of paper, a specific reduction in the width of an outer segment results in adding twice that width to the inner segment. This makes both the width and length of the paper chain link larger. This outer segment width reduction impacts assembly clearance.
Applying my invention to the three-ply strip, two crease lines rather than three are required. Again the single outer segment of the paper rectangle is narrower than the two inner segments that define the width of the strip. For the two-ply strip only one crease line is required. There are no outer segments with the two-ply paper rectangle. To maintain the 4.25 inch strip length, the two-ply strip is enlarged in width to reduce clearance and strengthen the chain. With the strip length a constant, the gauge stops for two, three and four-ply strips are the same, simplifying the paper chain tray design when adding a second or third ply option to a single paper tray embodiment.
Cutting an 8.5 by 11 sheet in Lift lengthwise provides 4.25 inches long rectangles for the two-ply, three-ply and four-ply strips. Cutting the sheet lengthwise into three equal parts provides 3.67 inch long paper chain strips. The strip width in this option requires the paper rectangle width to be reduced for correct assembly clearance, providing 39 paper rectangles per sheet. The number of paper rectangles per sheet depends on both the way the main sheet is cut and the number of ply in the strip. The result ranges from fourteen to thirty nine paper rectangles. Each change in paper rectangle length defines a class of embodiments.
Drawing No. 1 shows the paper chain process steps for a tour ply-paper chain.
Drawing No. 2 shows a molded paper chain tray having the three parallel channels of a four-ply paper chain.
Drawing No. 3 shows a molded or assembled embodiment of the invention.
Drawing No. 4 shows the cross-section of an extruded paper chain tray with stop gauges to accommodate a single strip length for both the two-ply and four-ply options.
Utilizing the channel design to position the crease lines allows the making of crease lines without removing and rotating the paper rectangle. Fewer manipulations make the design more efficient and child friendly.
Parallel channels are made in a paper chain tray with the inner most edge of each channel referenced to a back support. Said inner most edges of the channels provide the positioning of crease lines over the length of a paper rectangle. The paper rectangle is placed on the tray and against the back support. The stylus is forced against the inner crease edge of each channel and drawn the length of the paper rectangle, providing sharp crease lines for accurate folding.
The opposite edges of said same channels act to guide the stylus, said stylus operating at a low angle with the surface of the tray to make sharp creases. This design minimizes forcing of paper into the channels that can broaden the crease, alter the crease line positioning and prevent penetration of the paper.
By accurately controlling the crease lines of both the paper rectangles and the strips, the outer segment(s) of both can be held narrower than the inner segments, thereby avoiding fold interference between said infolded legs. Note that the two-ply rectangle does not have outer segments and this has no fold interference.
Paper strips are creased using gauge stops and corners. The strip is placed against the gauge stop and wrapped around the relevant corner. Pressing the strip against said corner creases said strip at the fold line position.
Handling paper chain links can sometimes collapse the passages between legs of said links, making assembly difficult Tapering one end of said stylus to a thin edge creates a tool for probing open said passages, allowing insertion of the next link.
Prototypes were made with wood. Plastic molding and extrusion are options. The invention can include single or multiple ply embodiments, or, by changing strip length, classes of embodiments. This invention is not intended to exclude such obvious extensions of the invention.