Adjustable - sold dumbbells
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One embodiment of the Adjustable-Solid Dumbbell having a hitch pin (20) which joins with dumbbell shaft (22). The assembly produces a preferred method of retaining add on weight plates (not shown) on a dumbbell shaft. The proposed dumbbell shaft having multiple holes enables the use of a selected number of add on weight plates. A dumbbell body is constructed in a way which attaches a specific weight. The Adjustable-Solid Dumbbells can be manufactured in different sizes to accommodate multiple weight ranges. Other embodiments are described and shown.

Chrysanthus, Philip (Broadview Heights, OH, US)
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Primary Examiner:
Attorney, Agent or Firm:
I claim:

1. An adjustable solid dumbbell of the type comprising a shaft having multiple holes located near shaft ends for the purpose of accepting hitch pins, also known as hair pin cotters.

2. The adjustable solid dumbbell of claim 1 wherein said body of material is composed of steel and cast iron.

3. The adjustable solid dumbbell of claim 1 wherein said shaft is adjacent to weight plates giving said dumbbell a predetermined weight.

4. The adjustable solid dumbbell of claim 1 wherein said dumbbell possesses a handle affixed to said shaft.

5. The adjustable solid dumbbell of claim 4 having said handle is adjacent to large washers located between handle flanges and weight plates.

6. The adjustable solid dumbbell of claim 4 wherein said handle is knurled, producing a textured finish.

7. The adjustable solid dumbbell of claim 3 having said weight plates are machined producing a hole accepting an assembly ring.

8. The adjustable solid dumbbell of claim 7 wherein said ring is composed of steel.

9. The adjustable solid dumbbell of claim 7 wherein said ring is properly machined to closely fit the finished assembly.

10. The adjustable solid dumbbell of claim 7 wherein said ring attaches last on both ends and completes dumbbell assembly.

11. An adjustable solid dumbbell of the type comprising a shaft having multiple holes located near shaft ends for the purpose of accepting hitch pins, also known as hair pin cotters, characterized in that the said hitch pin is used for the purpose of retaining add on weight plates.

12. The adjustable solid dumbbell of claim 11 wherein said hitch pin comprises a wire type body.

13. The adjustable solid dumbbell of claim 11 wherein said hitch pin is manufactured in a way of producing a spring like action for the purpose of self retention once installed on dumbbell assembly.

14. The adjustable solid dumbbell of claim 11 characterizes the use of add on weight plates. Add on weight plates are used in conjunction with adjustable solid dumbbells producing multiple weights.



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.


In the drawings, closely related figures have the same number but different alphabetic suffixes.

FIGS. 1A to 1B shows a dumbbell handle and large washer in accordance with each embodiment.

FIGS. 2A to 2B shows a dumbbell shaft in accordance with an interacting hitch pin (hair pin cotter).

FIGS. 3A to 3B shows a dumbbell weight plate side view in accordance with an steel assembly ring.

FIG. 4 shows an complete Adjustable-Solid Dumbbell assembled.


18Hole20Hitch Pin
26Steel Ring28Hole
30Weight Plate32Counter Bore

Detailed Description—FIG. 4—Preferred Embodiment

One embodiment of the Adjustable-Solid Dumbbell is illustrated in FIG. 4. The dumbbell illustrated consists of eight parts. A handle 14 has a knurled body with two flanges 16 permanently attached producing an weldment. The size of the handle will vary in accordance to the specified dumbbell size. Two large washers 12 are shown and are used to fine tune the size and weight of the intended dumbbell. Weight plates 30 are placed and will vary in size in accordance with a specified dumbbell weight. The weight plate hole 34 (FIG. 3) is countered bored 32 (FIG. 3) at the outer side of plate to accept a steal assembly ring 26 (FIG. 3) A dumbbell shaft 22 is shown having drilled holes to accept a hitch pin 20 FIG. (2A). The shaft size will vary in accordance with a specified dumbbell size. The dumbbell shaft 22 passes through all parts. The steal assembly ring 26 (FIG. 3) is placed last on the assembly at the outer sides of the weight plates 30 then inserted in the counter bore hole 32 (FIG. 3) then welded to the dumbbell shaft producing a weldment completing a Adjustable-Solid Dumbbell.

Operation—FIGS. 2A, 4

The manner of using Adjustable-Solid Dumbbells given procedure of retaining add on plates (not shown) enables the use of a hitch pin 20 (FIG. 2A) (hair pin cotter). As shown in FIG. 4, multiple holes 24 enables the positioning of hitch pin 20 (FIG. 2A) in different locations. Add on weight plates are assembled onto the dumbbell shaft 22 (FIG. 4) aligning with coordinated holes 24 (FIG. 4). Retaining multiple add on weight plates enables a user to adjust dumbbell weight through a given range. Hitch pin 20 (FIG. 2A) is inserted by hand into holes 24 (FIG. 4). Pin retention is caused by a spring like action built into the hitch pin 20 (FIG. 2A). Adjustable-Solid Dumbbells are manufactured in multiple dumbbell weights. Dumbbells then can be used within a specified dumbbell weight range, for example, a 25 lb. Adjustable-Solid Dumbbell can be adjusted to 45 pounds using multiple weight plates.


From the description herein, advantages derive from the embodiments of my Adjustable-Solid Dumbbells and are evident.

a) The method of changing and retaining weight plates are simplified, creating a user friendly adjustable dumbbell.

b) The use of hitch pins (hair pin cotters) to retain weight plates, produces a very secure method of retaining add on weight plates.

c) Adjusting the dumbbells does not require the need to move large weight plates.

d) Cast iron weight plates can be used for the bulk of the weight, minimizing machine operations.

e) Less time and parts are required in the manufacturing process thus reducing cost.

f) Minimal dumbbell pairs are needed to obtain large dumbbell weight ranges.

Conclusion, Ramifications and Scope

Accordingly, the reader will see that the Adjustable-Solid Dumbbells various embodiments provide effectiveness and efficient uses of these dumbbells while engaging in weight lifting. In addition to the uses, Adjustable-Solid Dumbbells will provide good value and a very durable product. Furthermore, dumbbells have additional advantages in that

they permit quick production requiring less man power to produce.

they provide large knurled handles for good gripping.

they can be used in both home and commercial applications.

they provide immediate weight plate change.

they have only one moving part, wear is extremely minimal.

they do not require complicated or cumbersome collars.

The description above contains many specifications, however it should not be construed as limiting the scope of the embodiments but as merely providing figures and illustrations of some of the proposed embodiments. For example, the dumbbell handle can have different shapes such as having a taper or a varying grip size etc.

Thus the scope of the embodiment needs to be established by the appended claims and their legal equivalents, rather then by the examples given.