Magnetic dampening unit for an exercise gym apparatus

Abstract

A magnetic dampening unit for an exercise gym apparatus includes a plate and an axle secured on the plate. A flywheel is rotatably mounted on the axle and has a hub. A stub is formed at a central portion of the hub and opposed to the plate. A non-magnetic metal member is provided in the flywheel and faces the plate. A disk is rotatably mounted on the axle and between the flywheel and the plate. A resilient member is mounted on the axle and between the disk and the plate. Multiple permanent magnets are provided on the disk with an alternate arrangement of N-polarities and S-polarities and facing the non-magnetic metal member. Two cables are provided on the disk and extend out from the plate. When drilling the flywheel for a dynamic balance, material waste will not be drawn to the magnets and the flywheel can be easily cleaned.

Description

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to an exercise gym apparatus, and more particularly to a magnetic dampening unit for an exercise gym apparatus

2. Description of Related Art

With reference to FIG. 3, in a conventional exercise gym apparatus, a magnetic dampening unit has an axle (48) mounted on a plate (50). A flywheel (40) is rotatably mounted on the axle (48), and a non-magnetic metal member (46) is mounted between flywheel (40) and the plate (50). A resilient member (49) is mounted on the axle (48) and between the non-magnetic metal member (46) and the plate (50). The flywheel (40) has a hub (41) and a stub (42) formed at a center of the hub (41). Bearings (421) are provided in the stub (42) to rotatably mount the flywheel (40) on the axle (48). A belt (60) is provided on the stub (42) and connected to a crank (not shown) of the exercise gym apparatus.

A recess (43) is defined in the flywheel (40) and faces the non-magnetic metal member (46). An iron member (44) is provided in the recess (43) and multiple permanent magnets (45) are mounted on the iron member (44) with an alternate arrangement of N-polarities and S-polarities to face the non-magnetic metal member (46). Two cables (47) fixed on the non-magnetic metal member (46) and extend out from the plate (50). The cables (47) are connected to an adjusting device (not shown) and can be pulled to a gap between the non-magnetic metal member (46) and the permanent magnets (45). Then, a distribution of magnetic forces of the permanent magnets (45) is changed so as to adjust a dampening force of the flywheel (40).

The flywheel (40) must be machined carefully in manufacture to achieve the necessary dynamic balance for vibration-free operation when fitted to the apparatus. A common method for achieving dynamic balance is drilling at proper portions of the flywheel (40). Because the flywheel (40) is made of iron, the small amounts of waste material cut from the flywheel (40) will be drawn by the permanent magnets (45) to still adhere to the flywheel (40), and it is difficult to clear away the waste material. Furthermore, as the permanent magnets (45) are directly provided in the flywheel (40), the flywheel (40) itself may become magnetized such that the magnetic forces of the permanent magnets (45) are weakened. Therefore, the dampening force of the dampening unit will become low.

Therefore, the invention provides a magnetic dampening unit for a gym apparatus to mitigate or obviate the aforementioned problems.

SUMMARY OF THE INVENTION

The main objective of the present invention is to provide a magnetic dampening unit for an exercise gym apparatus that can be easily configured for a dynamic balance.

Other objectives, advantages and novel features of the invention will become more apparent from the following detailed description when taken in conjunction with the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a cross sectional view of a magnetic dampening unit in accordance with the present invention;

FIG. 2 is a cross sectional view of the magnetic dampening unit in adjustment; and

FIG. 3 is a cross sectional view of a conventional magnetic dampening unit.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT

With reference to FIGS. 1 and 2, a magnetic dampening unit for an exercise gym apparatus in accordance with the present invention includes an axle (17) mounted on a plate (20) of the exercise gym apparatus (not shown). A flywheel (10) is rotatably mounted on the axle (17). The flywheel (10) is made of plastic material and provided with an iron ring (1101) embedded therein by means of injection molding. The flywheel (10) has a hub (11), and a stub (12) is formed at a central portion of the hub (11) and opposed to the plate (20). Multiple bearings (121) are received in the stub (12) to rotatably install the flywheel (10) on the axle (17). A recess (13) is defined in the flywheel (10) and faces the plate (20).

A disk (15) made of a non-magnetic metal is movably mounted on the axle (17) and received in the recess (13). A resilient member (18) is provided on the axle (17) between the disk (15) and the plate (20). Multiple permanent magnets (16) are mounted on an interior side of the disk (15) with an alternate arrangement of N-polarities and S-polarities. A non-magnetic metal member (14) is mounted in the recess (13) and faces the permanent magnets (16). Two first cables (19) are formed on an exterior side of the disk (15) and extend out from the plate (20). A belt (30) is provided on the stub (12) and connected to a wheel (not shown) for driving the magnetic dampening unit.

A pulley (21) is provided on the plate (20) and the first cables (19) are fastened on the pulley (21). A second cable (22) is fastened on the pulley (21) and connected to an adjusting device (not shown). When the pulley (21) is turned by the second cable (22), the first cables (19) can be pulled to move the disk (15) along the axle (17) so as to adjust a gap between the permanent magnets (16) and the non-magnetic metal member (14). Then, the distribution of the magnetic force of the disk (15) is changed, and the dampening effect of the flywheel (10) is adjusted.

Because the permanent magnets (16) are provided in the disk (15) and separated from the flywheel (10), waste material cut from the flywheel (10) during drilling for dynamic balance of the flywheel (10) will not be drawn to the permanent magnets (16) and the flywheel (10) can be easily cleaned. Moreover, the permanent magnets (16) are provided adjacent to the non-magnetic metal member (14) and the disk (15), so the magnetic forces of the permanent magnets (16) will not be weakened.

It is to be understood, however, that even though numerous characteristics and advantages of the present invention have been set forth in the foregoing description, together with details of the structure and function of the invention, the disclosure is illustrative only, and changes may be made in detail, especially in matters of shape, size, and arrangement of parts within the principles of the invention to the full extent indicated by the broad general meaning of the terms in which the appended claims are expressed.

Claims

1. A magnetic dampening unit for an exercise gym apparatus, the magnetic dampening unit comprising:

a plate (20);

an axle (17) secured on the plate (20);

a flywheel (10) rotatably mounted on the axle (17), the flywheel (10) having a hub (11), a stub (12) formed at a central portion of the hub (11) and opposed to the plate (20), a non-magnetic metal member (14) provided in the flywheel (10) and facing the plate (20);

a disk (15) movably mounted on the axle (17) and between the flywheel (10) and the plate (20);

a resilient member (18) mounted on the axle (17) and between the disk (15) and the plate (20);

a plurality of permanent magnets (16) provided on the disk (15) with an alternate arrangement of N-polarities and S-polarities and facing the non-magnetic metal member (14);

two first cables (19) provided on the disk (15) and extending out from the plate (20); and

a belt (30) provided on the stub (12).

2. The magnetic dampening unit as claimed in claim 1, wherein the flywheel (10) has two bearings (121) provided in the stub (12) for rotatably installing the flywheel (10) on the axle (17).

3. The magnetic dampening unit as claimed in claim 1, wherein the flywheel (10) has a recess (13) defined at a side facing the plate (20), the non-magnetic metal member (14) is formed in the recess (13) and the disk (15) is located in the recess (13).

4. The magnetic dampening unit as claimed in claim 3, wherein the balance (10) is made of plastic material by means of injection molding and provided with an iron ring (101) embedded in the flywheel (10).

5. The magnetic dampening unit as claimed in claim 1, further comprising a pulley (21) provided on the plate (20), the first cables (19) having distal ends fastened on the pulley (21).

6. The magnetic dampening unit as claimed in claim 5, further comprising a second cable (22) fastened on the pulley (21).