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Adjustable - sold dumbbells

Adjustable - sold dumbbells description/claims

This application claims the benefit of provisional patent application Ser. No. 60/881,204, filed Jan. 19, 2007 by the present inventor.

Not Applicable

Not Applicable

1. Field of the Invention

This invention relates to the use of hitch pins (also known as hair pin cotters) which are used to retain weight plates on a dumbbell shaft.

2. Prior Art

For many years, common methods of retaining weight plates to dumbbell shafts are known as collars. Bolt or t-bolt collars makes use of a bolt to clamp through a collar body onto a dumbbell shaft. This type of collar can loosen while in use from the movement of the weight plates.

There after many types of adjustable dumbbells were designed in such ways of manually changing dumbbell weight. U.S. Pat. No. 6,083,144 to Towley and Olson (2000) describes a complex dumbbell assembly using many machined parts which are prohibitively expensive to manufacturer. U.S. Pat. No. 6,416,446 to Krull (2002) discloses a dumbbell system comprising of an complex selector mechanism complicating the manufacturing process, thus raising cost.

Although the dumbbell handle and collar combination has been in use for many years, they produce a dumbbell assembly that is clumsy to use and may not properly secure the weight plates.

Among the types of dumbbell collars proposed for example, U.S. Pat. No. 5,603,680 to Larsen (1997) discloses a collar long in size producing a dumbbell cumbersome to use. Although this method of retaining weight plates to is less complicated, it is limited to a certain size and length of dumbbell shafts. This type of dumbbell collar is expensive to manufacture. The heretofore known methods of adjusting dumbbells suffer from a number of disadvantages:

(a) Their manufacturing processes requires great tooling and machine operations adding extra man hours and complicating production methods.

(b) The need to produce an excess number of parts requires additional assembly hours.

(c) Complicated operating mechanism may not always engage or function properly minimizing user effectiveness.

(d) The excessive number of manufactured parts requires additional finish processes such as chrome or zinc plating or coatings.

(e) Increased machine, finish and assembly processes raises the manufacturing cost. Due to the competitive nature of these products, production must adhere to low manufacturing cost to enable any commercial value.

In accordance with one embodiment a adjustable solid dumbbell comprises a dumbbell shaft having drilled holes accepting a hitch pin (hair pin cotters) to retain weight plates.

• Provisional Patent
• Utility Patent

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