A full set of traditional dumbbells has various pairs of dumbbells with different mass, e.g. a pair of 5 pound dumbbells, a pair of 10 pound dumbbells, and so on. Such dumbbells are used for weight training exercises such as biceps curls, triceps extensions, etc. Different users will use whatever size dumbbells are most suited to their particular physical condition and exercise needs. For example, one user might lift 10 pound dumbbells while another user might lift 50 pound dumbbells.
Such a dumbbell set is both costly to purchase and requires a fair amount of storage space. Storage racks are needed simply to store the various pairs of dumbbells. As a practical matter, individuals and small gyms or exercise clubs may not be able to afford either the money or the storage space required for a full set of traditional dumbbells.
Selectorized dumbbells overcome the cost and space obstacles presented by traditional dumbbells. In a selectorized dumbbell, a plurality of weights are nested together. The weights provide a stack of nested left weight plates and a stack of nested right weight plates. The left and right stacks of weight plates are separated from one another by a gap.
In a selectorized dumbbell, a handle is inserted into the gap between the left and right stacks of weight plates. A selector is then manipulated to determine how many of the left and right weight plates of the weights are coupled to the left and right ends of the handle. Once the selector is positioned to pick up a selected number of weights, the handle can then be lifted by the user from between the stacks of weight plates. The selected number of weights will rise with the handle to be used in performing various exercises with the dumbbell.
The obvious advantages of selectorized dumbbells are the cost and space savings provided to the purchaser. Only two dumbbells need be purchased and not an entire set. Yet, these two dumbbells can provide a wide range of exercise mass depending upon how many of the nested weights are coupled to the handle by the selector. Moreover, the only storage space required is that needed for two dumbbells and the nested weights that accompany them. All of this can be stored on a small rack that takes up only a few square feet of floor space. Thus, a single pair of selectorized dumbbells provides an economical alternative to a full set of traditional dumbbells.
The various weights of a selectorized dumbbell must nest inside one another in a smooth and reliable fashion. In addition, the selector coacts with portions of the weights so as to be able to pick up different numbers of weights when the selector is moved between different positions. This requires that the weights, selector and handle all remain aligned within fairly close tolerances. If these tolerances are not maintained, then the selector or the weights may jam and prevent use of the selectorized dumbbell.
While traditional dumbbells are fairly impervious to damage, this is not the case for the more complicated and sophisticated structure of selectorized dumbbells. The weights of a selectorized dumbbell are sometimes dropped onto a floor. This might happen with just a single weight that gets knocked off a rack. Or the user can accidentally drop an entire dumbbell loaded with one or more of the weights onto the floor. In any event, if this happens from higher than about two feet, the weights of the dumbbell can be bent or misaligned or various components of the selector can become bent, misaligned or damaged.
Many weights used in a selectorized dumbbell comprise a pair of spaced weight plates welded to a pair of rails. When these weights are bent, most people do not have the welding equipment and experience to repair them. Usually, the bent weights must be replaced. This is done either by the owner of the dumbbell at his or her own expense or by the manufacturer of the dumbbell as part of a warranty claim. Sometimes, the entire dumbbell might have to be replaced if the damage also extends to the selector or the handle.
In addition, other selectorized dumbbells use rigid plastic protrusions on the weights that coact with selectors having metallic or rigid plastic parts. It sometimes happens that the plastic protrusions on the weights or the plastic parts on the selectors break off. Sometimes, the metallic parts on the selectors bend. When this happens, it is generally impossible to repair the damaged parts, particularly when the damage occurs to the broken plastic weight protrusions or plastic selector parts.
Accordingly, it would be an advance in the exercise art to provide a selectorized dumbbell that can absorb impact shocks without significant damage being done.