HK1120009B - Vehicle wheel balance weights and a method of forming a vehicle wheel balance weights - Google Patents

Description

Wheel balance weight and method of forming same

Technical Field

The invention relates to a wheel balance weight.

Background

To reduce excessive vibration, the wheels are typically balanced by placing weights at selected locations. One known weight includes a mass portion that is attached to a wheel rim using a spring clip. In view of high mass and low cost, such weights have in the past been made primarily of lead. For example, such weights are made by casting molten lead around heat treated spring clips. As a result, a portion of the clip will be embedded within the mass portion, while another portion extends from the mass portion for attachment to the rim.

For various reasons, it is now desirable to manufacture such weights from materials other than lead.

Disclosure of Invention

The present invention provides various configurations for a wheel weight. The preferred embodiment uses iron or low carbon steel for the blocks instead of lead, which has been commonly used in the past. The mass is attached to the wheel using a spring clip, preferably made of spring steel. The spring clip includes an attachment portion secured to the mass portion by an interference fit. For example, a pocket may be formed in the mass to accommodate the attachment portion of the spring clip. After insertion of the connecting portion, the pocket can be closed so that the spring clip is securely retained. The pocket is defined by first and second seamless webs respectively located at both ends of the clip-securing pocket such that the ends are closed.

Drawings

A full and enabling disclosure of the present invention, including the best mode thereof, directed to one of ordinary skill in the art, is set forth more particularly in the remainder of the specification, including reference to the accompanying figures wherein:

FIG. 1 is a front elevational view of a wheel weight constructed in accordance with the present invention;

FIG. 2 is a rear elevational view of the wheel weight of FIG. 1;

FIG. 3 is a side view of the wheel weight of FIG. 1;

FIG. 4 is a cross-sectional view taken along line 4-4 of FIG. 1, showing the wheel weight mounted on the wheel rim;

5A-5C are block section views showing insertion of a spring clip into a cold-formed pocket in accordance with the present invention;

FIG. 6 is an enlarged view of the portion shown in FIG. 5B, showing an elongated recess formed in the attachment portion of the spring clip;

FIG. 7 is a broken-away view showing the attachment portion of an alternative spring clip having a series of spaced apart tabs formed thereon;

FIG. 8 is a cross-sectional view taken along line 8-8 of FIG. 7;

repeat use of reference characters in the present specification and drawings is intended to represent same or analogous features or elements of the invention.

Detailed Description

It is to be understood by one skilled in the art that the present discussion is a description of exemplary embodiments only, and is not intended as limiting the broader aspects of the present invention, which broader aspects are embodied in the exemplary constructions.

Fig. 1 through 3 illustrate a wheel weight 10 constructed in accordance with an embodiment of the present invention. As shown, the wheel weight 10 includes a mass portion 12 to which a spring clip 14 is attached. As will be described more fully below, clip 14 (which is preferably made of spring steel) is positioned within a cavity (or "dimple") formed on mass portion 12. This often results in a slightly elevated surface 16 "in front" of mass portion 12. (As used herein, the front of weight 10 is the side facing away from the rim). It can be seen that the block portion 12 has an arc shape approximating the rim periphery to which it is attached.

Indicia, as shown at 18 and 20, are preferably provided on mass portion 12 to indicate the mass and/or type of weight. Typically, the indicia are formed by stamping (stamp) onto the mass so as to be durable. The use of such markings on wheel weights is well known, but has previously been provided on the front. Placing the indicia on the back provides a more pleasing product because it is hidden during use.

Massive portion 12 is preferably made of a suitable quality of lead-free material, such as iron or mild steel. Generally, 1008 steel is particularly preferred. In some cases, particularly with higher mass weights, copper may also be used.

Referring now to FIG. 4, clip 14 is used to attach weight 10 to the rim 22 of a wheel. As shown, block portion 12 is preferably configured to snugly fit under the curved lip of rim 22. It can be seen that the cross-sectional profile of block portion 12 has a smooth outer surface around its periphery. This is in contrast to many weights of the prior art which present rough edges. In addition to providing a more pleasing appearance, this configuration also tends to minimize rim damage caused by sharp surfaces.

In this case, it is also desirable that block portion 12 be configured to define a top chamfer 24 and a bottom chamfer 26. Chamfers 24 and 26 are formed as relatively flat, sloped surfaces extending axially along the back of block portion 12.

Chamfer 24 facilitates attachment of weight 10 by minimizing the amount of stretch required on clip 14 to properly seat mass portion 12 below the rim lip. The chamfer 26 provides clearance for various visible features on modern rims, such as spokes 28.

Fig. 5A-5C illustrate one manner of attaching clip 14 in accordance with the present invention. In this regard, fig. 5A shows a cross-sectional view of mass portion 12 prior to installation of clip 14. Block portion 12 is preferably made from a "wire" that is pre-formed to the desired cross-sectional profile. For example, the chamfers 24 and 26 may be defined on the wire at the time of manufacture. A predetermined length of wire is then cut and formed into the desired arc to create block portion 12.

Referring now to fig. 5B, it can be seen that a dimple 30 has been formed in mass portion 12. The recess 30 is preferably cold-formed (cold-formed) by inserting a die (land) of suitable configuration into the top of the block portion 12. The pockets 30 are preferably formed closed (closed) at both ends, such as by a web 32 (and similar webs at the other end). Mechanically applied zinc (or other suitable coating or treatment) may be applied after the die step to form a protective coating on mass portion 12.

After forming pocket 30, connecting portion 34 of clip 14 is inserted therein. Extension 36 of clip 14 remains outside mass portion 12 for engaging the rim.

Referring now to fig. 5C, after insertion of the connecting portion 34, the pocket 30 is forced closed (as indicated by arrow 38). As a result, clip 14 is firmly secured to mass portion 12.

Referring now to fig. 6, it is generally desirable to provide connecting portion 34 of clip 14 with features that improve the engagement between mass portion 12 and clip 14. In this regard, FIG. 6 illustrates an embodiment wherein an axial groove 40 is defined across the front surface of the connecting portion 34. When pocket 30 is closed, the metal of the block portion will flow into groove 40 to form an interference fit.

Fig. 7 and 8 illustrate an alternative embodiment where a plurality of spaced apart knobs 42 are pressed into the connecting portion 34 of the clip 14. Nubs 42 also serve to provide a secure engagement between mass portion 12 and clip 14 in a manner similar to recess 40.

Reference is made to U.S. application No.10/724,000 filed on 26/11/2003 and to U.S. application No.10/620,309 filed on 15/7/2003, both of which are commonly assigned. Each of these applications is incorporated by reference herein in its entirety.

For a number of reasons, it is desirable to use cold-formed dimples to attach clip 14 to mass portion 12. For example, casting a steel block in a manner similar to a lead weight would cause the clip to lose heat treatment properties. In addition, such techniques are often uneconomical.

Although an embodiment using a single clip is shown, it will be understood by those skilled in the art that a larger mass portion may require more than one clip spaced along its axial length.

While preferred embodiments of the present invention have been shown and described, modifications and variations may be made by one skilled in the art without departing from the spirit and scope of the invention. Additionally, it should be understood that aspects of the various embodiments may be interchanged both in whole or in part. Furthermore, those skilled in the art will appreciate that the foregoing description is by way of example only, and is not intended to limit the invention so further defined in such appended claims.

Claims (20)

1. A wheel weight, comprising:

a block portion cold formed from a lead free material, the block portion having a front face and a rear face, the rear face of the block portion being adapted to lie side-by-side against the rim;

the mass portion defining a clip securing pocket formed therein, the clip securing pocket defined by first and second seamless webs respectively located at both ends of the clip securing pocket such that the ends are closed; and

a heat-treated spring clip having an attachment portion inserted into and held in the clip securing pocket such that the clip is secured to the mass portion, the clip further having an extension portion for engaging the rim.

2. The wheel weight of claim 1, wherein the lead-free material is low carbon steel.

3. The wheel weight of claim 2, wherein the lead-free material is 1008 steel.

4. The wheel weight of claim 1, wherein the lead-free material is iron.

5. The wheel weight of claim 1, wherein the lead-free material is copper.

6. The wheel weight of claim 1, wherein the attachment portion of the spring clip defines at least one surface irregularity to facilitate retention of the attachment portion within the clip securement cavity.

7. The wheel weight of claim 6, wherein the at least one surface irregularity includes a transverse groove defined within the connecting portion of the spring clip.

8. The wheel weight of claim 6, wherein the at least one surface irregularity includes a plurality of spaced apart ridges defined within the attachment portion of the spring clip.

9. The wheel weight of claim 1, wherein the mass portion defines at least one chamfer on the rear face.

10. The wheel weight of claim 9, wherein the at least one chamfer includes a top chamfer formed as an inclined surface extending axially along the mass portion.

11. The wheel weight of claim 1, wherein the mass portion includes indicia located at the rear face.

12. The wheel weight of claim 11, wherein the indicia represents mass.

13. A method of forming a wheel weight, wherein the weight has a mass portion and a spring clip, the method comprising the steps of:

(a) providing a block portion of lead-free material, the block portion having an arcuate shape along a longitudinal axis of the block portion;

(b) cold forming a clip fastening recess in the block portion, the clip fastening recess being defined by first and second seamless webs respectively located at both ends of the clip fastening recess such that the both ends are closed;

(c) inserting the attachment portion of the spring clip into the clip securing pocket, the spring clip further having an extension portion for engaging the rim; and

(d) closing the clip-securing pocket against the attachment portion so as to attach the mass portion to the clip.

14. The method of claim 13, wherein the lead-free material is low carbon steel.

15. The method of claim 14, wherein the lead-free material is 1008 steel.

16. The method of claim 13, wherein the lead-free material is iron.

17. The method of claim 13, wherein the lead-free material is copper.

18. The method of claim 13, wherein said attachment portion of said spring clip defines at least one surface irregularity to facilitate retention of said attachment portion within said clip securement cavity.

19. The method of claim 18, wherein the at least one surface irregularity comprises a transverse groove defined within the connecting portion of the spring clip.

20. The method of claim 18, wherein said at least one surface irregularity comprises a plurality of spaced apart ridges defined within said attachment portion of said spring clip.