The Redivider Ping-Pong Paddle Invention

Last month I built a custom ping-pong paddle for my unique ambidextrous style. Since I was dealing with that sort of thing anyways, I wrote it up as an invention and so here is a full description of what I have unleashed upon the office ping-pong table.

Figure 1
Fig 1. Redivder Paddle in split aspect.

Problem

This ping-pong paddle design solves two distinct problems, one procedural and one temporal. Note that in practice, there has been no procedural challenge yet of ambidextrous ping-pong, and so the primary benefit of the design is the temporal problem of playstyle switching.

Temporal problem of dynamic play-style adjustment

The temporal problem comes more specifically to alternating playstyles. The inventor in question enjoys both the playstyle of having one paddle per hand, and of having a double paddle wielded in one hand. It is difficult to alternate between styles using standard paddles (and duct tape). The previous mechanism for creating a double paddle (assumed non-patentable due to its obvious nature) was to place two paddles together hilt to hilt (similar to fig. 2) and tape them in place. This allowed for the development of the double paddle playstyle, but consumed two normal paddles in the process. To switch between double paddle and two paddles could require reserving four paddles, which was not always available. To switch between styles without using a second pair of paddles required cutting off or reapplying the duct tape, which is a laborious task less enjoyable than that of playing ping pong.

Fig 2. The Redivider Paddle in combined aspect.
Fig 2. The Redivider Paddle in combined aspect.

Furthermore there exists an ITTF rule: “2.4.8 At the start of a match and whenever he changes his racket during a match a player shall show his opponent and the umpire the racket he is about to use and shall allow them to examine it.” Under this rule it is not feasible to change paddles between shots, and it is mildly disruptive to change paddles between points. Under the spirit of this rule, it is preferable to show any player new to the operation of this paddle the Redivider paddle and its complete functionality before a match starts, as opposed to interjecting with a paddle change and examination option mid-match.

Either of these two reasons would require sticking to one play style for an extended period of time, which is less than ideal for two reasons. Firstly each style has different advantages and disadvantage. The extra reach and fulcrum length of the double paddle allows for stronger play near the net and smash shots, while the split locations and closer grip on the two paddles allows for finer control on shots near the back of the table or when alternating sides. The Redivider design allows for conveniently choosing the ideal return style per shot, without switching paddles as per 2.4.8.

Procedural ruling of ambidextrous ping-pong

Playing ping-pong with multiple paddles has no clear ruling. Section 2.4.1 of the International Table Tennis Federation(ITTF) rules describes paddle requirements most broadly as “The racket may be of any size, shape or weight but the blade shall be flat and rigid.” The general phrasing of section 2.4 seems to imply that there exists for each player a singular paddle, but the implementation of the paddle is open for innovation. For ambidextrous players, it could be argued that one paddle in each hand violates this implicit rule. This paddle, which plays as both a single paddle and when as into two halves when temporarily split, provides an attempt at following the spirit of that implicit rule. It is still open to debate as to whether the detachment into two halves is sufficiently transformative, and as to whether two separate blades would contradict another implicit rule, but it does move in the direction of a single paddle. Namely that it is a fixed item with a clear and fixed transformation, which can further have said transformation left unused if so ruled for a specific match.

Solution

Overview

The Redivider paddle design consists of two paddles connected via attached magnets (see figures 1-3). The attachment mechanism in the final design (and some prototypes) was a combination of glue and duct tape. The glue provides the primary attachment mechanism, and the duct tape provides limited supplemental attachment. But the primary role of the duct tape is to provide a thin fabric-like barrier between the Neodymium magnets when connected. Without some form of barrier, such magnets are prone to impacting with such force that they chip and wear each other extremely quickly. The barrier has not yet been tested for long term protection, but has lasted through tens of connection events so far – a number which would almost certainly have irreparably damaged the magnets if they contacted each other directly.

For strength sufficient to maintain the paddle as one rigid body under normal play, while still able to be detached by humans (tested only with adult males of the species), two N42 grade 1”x1/8” Neodymium magnets were used per paddle. The combined size of the magnets being slightly larger than the paddle base assists with stability.

Fig 3. Magnets are used. Also provides better surface area for hilt shots.
Fig 3. Magnets are used. Also provides better surface area for hilt shots.

Magnet Polarity

The key finding from the prototyping phase was that the structure is much more stable with a specific magnet polarity. Initial prototypes would have 1-4 exposed north magnetic poles on one paddle and a corresponding number of exposed south magnetic poles on the other paddle. While this functions as expected for magnetic attachment, the force required to twist or snap the paddles apart is very low. It is then easy for the magnets to slide or peel away under normal play. This breaks the attachment between the two halves.
By instead exposing one north and one south pole on each paddle, the magnetic forces discourage sliding and peeling motions between the magnets. The force required to twist or snap the paddles apart is greatly increased, even though it is still not as high as the force required to pull them straight apart. The increase in force required is sufficient to prevent the paddle from separating under most normal play conditions.

This polarity effect had a greater effect than magnet size on the stability of the resulting link across various prototypes. However both increased magnet size and alternating polarity was required in order to reach the requisite level of strength for a mostly stable bond during normal use.

An additional benefit of this polarity arrangement is that the paddle will only lock in a very specific configuration. With like poles exposed on each paddle, it frequently occurred that the paddles would be locked together at unusual angles by accident (due to the haste in which the mechanism is operated under normal circumstances). These alternate angles included slight rotations of the double paddle configuration where one blade was rotated 0°-15° compared to the other. This proved more difficult to play with. With alternating poles the incidence of such mistakes greatly decreases. It is still possible to connect only one magnet securely, and leave the other side “dangling”, but this is a much grosser error and less likely to occur from haste.

Existing Alternatives

The inventor has no knowledge of existing solutions for these problems, or of other ambidextrous players who play with two paddles. Prior to prototyping of a new invention, a query was sent to a supplier of custom ping-pong paddles (uberpong) as to whether they provide paddles this custom. They did not offer customizations related to the issue at hand, but were nice enough that I bought some base materials (two normal paddles) from them.

Video

Finally, a video of it in action. Thanks to my co-workers for helping provide a cameraman and skilled (perhaps too skilled) opponent.

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