Multifunction gauge

A multifunction gauge includes a checking bar adapted to check wear of a roller chain, and a flexible checking member adapted to check wear of a sprocket and connected to the checking bar. The checking bar has a bar body that has opposite first and second end portions respectively having opposite first and second terminating ends. The checking bar further has spaced-apart first and second checking projections that project transversely from one side of the bar body.

CROSS-REFERENCE TO RELATED APPLICATION

This application claims priority of Taiwanese Application No. 101150152, filed on Dec. 26, 2012.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The invention relates to a multifunction gauge, more particularly to a multifunction gauge for checking wear of a sprocket and a roller chain.

2. Description of the Related Art

The sprockets and the roller chain of a drivetrain system for a bicycle may be worn after long-term use. A worn roller chain is lengthened, and may easily derail from the sprockets when being used in a single-speed bicycle, or affect the function of a rear derailleur when being used in a variable-ratio transmission system of a different kind of bicycle. A worn sprocket may easily slip relative to a roller chain and may not drive or be driven by the roller chain properly. Therefore, the sprockets and the roller chain of a bicycle need to be checked periodically.

There are separate sprocket and chain wear gauges for checking sprocket wear and roller chain wear, respectively. However, to check wearing of the drivetrain system of a bicycle, both of the sprocket wear gauge and the chain wear gauge are needed.

SUMMARY OF THE INVENTION

Therefore, the object of the present invention is to provide a multifunction gauge for checking wear of both a sprocket and a roller chain.

Accordingly, a multifunction gauge of the present invention is adapted for checking wear of a sprocket and a roller chain. The sprocket has a plurality of angularly spaced-apart sprocket teeth, and a plurality of sprocket grooves each being defined between a corresponding adjacent pair of the sprocket teeth. The roller chain includes a plurality of spaced-apart rollers, and a plurality of chain grooves each being defined between a corresponding adjacent pair of the rollers. The multifunction gauge includes a checking bar adapted to check wear of the roller chain, and a flexible checking member adapted to check wear of the sprocket and connected pivotally to the checking bar. The checking bar has a bar body that has opposite first and second end portions. The first end portion has a first terminating end adapted to engage one of the sprocket grooves when the flexible checking member is used to check wear of the sprocket. The second end portion is formed into a rod-shaped handle adapted for applying force when the flexible checking member is used to check wear of the sprocket. The second end portion has a second terminating end that is opposite to the first terminating end along a longitudinal direction of the checking bar. The checking bar further has spaced-apart first and second checking projections that project transversely from one side of the bar body between the first and second terminating ends and that are adapted to check wear of the roller chain. The first checking projection is proximal to the first terminating end. The second checking projection is proximal to the second terminating end of the second end portion.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

As shown inFIG. 1, the first preferred embodiment of a multifunction gauge according to the present invention is adapted for checking wear of a drivechain of a bicycle (not shown) which includes a roller chain900(seeFIG. 6) and a cogset800(a sprocket assembly, seeFIG. 2). Referring toFIG. 2, the cogset800includes a plurality of sprockets801each having a plurality of angularly spaced-apart sprocket teeth802, and a plurality of sprocket grooves805. Each of the sprocket grooves805is defined between a corresponding adjacent pair of the sprocket teeth802. Each of the sprocket teeth802has a first abutment surface803and a second abutment surface804opposite to the first abutment surface803. Generally, the cogset800is driven by a roller chain (not shown) to rotate in a rotational direction806, so the first abutment surface803of each of the sprocket teeth802is worn more seriously than the second abutment surface804. Referring toFIG. 6, the roller chain900includes a plurality of spaced-apart rollers901, and a plurality of chain grooves902, each of which is defined between a corresponding adjacent pair of the rollers901.

Referring toFIGS. 1,5and6, the multifunction gauge includes a checking bar3adapted to check wear of the roller chain900, and a flexible checking member4adapted to check wear of the sprockets801and connected pivotally to the checking bar3.

The checking bar3has a bar body30and spaced-apart first and second checking projections33,34.

The bar body30is configured as a flat bar, and has two opposite planar side surfaces310facing oppositely away from each other, a rule surface311interconnecting the side surfaces310, and opposite first and second end portions32,31.

The first end portion32has a first terminating end321adapted to engage one of the sprocket grooves805when the flexible checking member4is used to check wear of the sprocket801. Each of the side surfaces310has a rounded periphery324at the first terminating end321. The first end portion32further has a rounded end surface322that is disposed transversely between the side surfaces310and that interconnects the rounded peripheries324of the side surfaces310. The rounded end surface322has a contact point320(seeFIG. 5) for contacting the sprocket801when the flexible checking member4is used to check the wear of the sprocket801. The first end portion32further has two concaved surfaces323that are connected respectively to opposite ends of the rounded end surface322. Each of the concaved surfaces323interconnects the side surfaces310.

The second end portion31is formed into a rod-shaped handle adapted for applying force when the flexible checking member4is used to check wear of the sprocket801. The second end portion31has a second terminating end312that is opposite to the first terminating end321along a longitudinal direction of the bar body30.

The first and second checking projections33,34project from the rule surface311of the bar body30transversely of the longitudinal direction between the first and second terminating ends321,312and are adapted to check wear of the roller chain900. The first checking projection33is proximal to the first terminating end321. The second checking projection34is proximal to the second terminating end312.

The first checking projection33has a first abutment surface330that faces oppositely away from the second checking projection34. The second checking projection has a second abutment surface340that faces oppositely away from the first checking projection33and that is flat. In this embodiment, the first abutment surface330has a curved or concave profile, but can also be flat.

A thickness of the bar body30decreases toward the rule surface311from a back surface313. Each of the first and second checking projections33,34has a thickness that decreases from the rule surface311in a direction away from the rule surface311.

The flexible checking member4is pivoted to the first end portion32of the bar body30of the checking bar3at a pivot point44between the first terminating end321and the first checking projection33. The structure and specification of the flexible checking member4is substantially the same as that of the roller chain900.

The flexible checking member4includes a plurality of first and second link units41,42that are interconnected in series in alternating arrangement. Each of the first and second link units41,42has two link plates411,421. The number of the first and second link units41,42of the flexible checking member4depends on the number of the sprocket teeth802of the sprocket801. In this embodiment, the flexible checking member4includes four first link units41and three second link units42. The flexible checking member4further includes a plurality of connecting pins413, each of which interconnects pivotally a corresponding adjacent pair of the first and second link units41,42, a proximal pin413′ that is disposed at the pivot point44and that interconnects pivotally a proximal end portion of a proximal one of the first and second link units41,42(i.e., the first link unit41that is proximal to the checking bar3inFIG. 1) and the first end portion32of the checking bar3, a distal pin413″ that is inserted in a distal end portion of a distal one of the first and second link units41,42(i.e., the first link unit41that is distal from the checking bar3inFIG. 1), a plurality of rollers414that surround rotatably and respectively the connecting pins413, a distal roller414″ that surrounds fittingly the distal pin413″, a plurality of sprocket tooth engaging spaces40, each of which is defined between a corresponding adjacent pair of the rollers414, and a distal sprocket tooth engaging space40″ that is define between the distal roller414″ and one of the rollers414adjacent to the distal roller414″. Preferably, the number of the sprocket tooth engaging spaces40ranges from 2 to 14. The proximal pin413′ extends through the side surfaces310of the bar body30such that the side surfaces310are opposite to each other in an axial direction of the proximal pin413′. The distal roller414″ is clamped between the link plates411of the distal one of the first link units41and is non-rotatable relative to the link plates411of the distal one of the first link units41. The distal roller414″ is greater than the rollers414in thickness. Referring toFIG. 5, in this embodiment, a distance between the proximal pin413′ and the contact point320is not smaller than a distance between an adjacent pair of the connecting pins413.

Referring toFIGS. 3 and 4, when the first preferred embodiment of the multifunction gauge is used to check wear of a sprocket801, the sprocket tooth engaging spaces40and the distal sprocket tooth engaging space40″ of the flexible checking member4are engaged respectively with a plurality of successive sprocket teeth802of the sprocket801, and the first terminating end321of the first end portion32of the checking bar3engages one of the sprocket grooves805of the sprocket801. A force is applied to the checking bar3in the rotational direction806such that the flexible checking member4is tensed. If the sprocket801is in a normal condition (seeFIG. 3), the flexible checking member4may be retained stably on the sprocket teeth802and will not disengage from the sprocket801. If the sprocket801is worn seriously (seeFIG. 4), the flexible checking member4may slip from the sprocket teeth802and move in the rotational direction806by the force. While the concaved surfaces323of the first end portion32are provided in this embodiment, they are not indispensable. The presence of the concaved surfaces323is for avoiding the interference between the first end portion32and the sprocket teeth802when the multifunction gauge is used to check the wear of the sprocket801.

Referring toFIG. 5, in an alternative approach, wear of the sprocket801is checked by the multifunction gauge when the first abutment surface803of each of the sprocket teeth802is worn slightly. Firstly, the sprocket tooth engaging spaces40(seeFIG. 1) are engaged respectively with a plurality of successive sprocket teeth802of the sprocket801, and the first terminating end321of the first end portion32of the checking bar3engages one of the sprocket grooves805of the sprocket801. However, the distal one of the first link units41is placed away from the sprocket801(as shown in dashed lines). Thereafter, a force is applied to the checking bar3in the rotational direction806such that the flexible checking member4is tensed, and the distal one of the first link units41is simultaneously caused to move toward the corresponding sprocket tooth802. If the sprocket801is worn slightly, the corresponding sprocket tooth802is unable to enter smoothly the distal sprocket tooth engaging space40″.

It is noted that when the sprocket teeth802of the sprocket801are worn slightly, the second approach is efficient to obtain more accurate results.

Referring toFIG. 6, when the first preferred embodiment of the multifunction gauge is used to check wear of the roller chain900, the first checking projection33is first inserted into one of the chain grooves902with the first abutment surface330abutting against a corresponding first roller901, and then the checking bar3is moved toward the roller chain900to check if the second checking projection34can be inserted into a predetermined chain groove902. In this embodiment, the predetermined chain groove902is the eighth chain groove902counted from the corresponding first roller901. If the second checking projection34cannot be inserted into the predetermined chain groove902(seeFIG. 7), the roller chain900is in a normal condition. If the second checking projection34can be inserted into the predetermined chain groove902(seeFIG. 8), the roller chain900may need to be replaced since it has been lengthened due to wear.

To sum up, the multifunction gauge of this invention is capable of checking wear of the roller chain900and the sprockets801of the drivechain of the bicycle. Compared with conventional separate chain and sprocket wear gauges, the multifunction gauge is more convenient.

Referring toFIG. 9, a second preferred embodiment of the multifunction gauge according to the present invention is generally similar to the first preferred embodiment in structure. The difference between the first and second preferred embodiments resides in that a distance (L1) between the proximal pin413′ and the contact point320of the second preferred embodiment is not smaller than a half of a distance (L2) between an adjacent pair of the connecting pins413.

Referring toFIGS. 10 and 11, a third preferred embodiment of the multifunction gauge according to the present invention is different from the first preferred embodiment in that the bar body30has a uniform thickness, and that the bar body30is greater than the first and second checking projections33,34in thickness.