US20070080088A1

US20070080088A1 - Preassembly of cooperating parts

Info

Publication number: US20070080088A1
Application number: US11/508,650
Authority: US
Inventors: Jason Trotter; Robert Dutzi; Kenneth Dobson
Original assignee: Illinois Tool Works Inc
Current assignee: Illinois Tool Works Inc
Priority date: 2005-10-06
Filing date: 2006-08-23
Publication date: 2007-04-12

Abstract

A grommet is provided with an anchoring structure or structures for capturing a shrink wrap sleeve thereagainst, to inhibit the sleeve from sliding off the grommet. The anchoring structures are remote from an end surface of the grommet in an assembly.

Description

CROSS-REFERENCE TO RELATED APPLICATIONS

The present regular United States Patent Application claims the benefits of United States Provisional Application Ser. No. 60/724,359, filed Oct. 6, 2005.

FIELD OF THE INVENTION

The present invention relates generally to the grouping, preassembly and fixation of adjacent cooperating parts that may not securely attach one to another, for subsequent installation of the group as one subassembly in an overall assembly.

BACKGROUND OF THE INVENTION

It is known to provide preassembled parts and subassemblies that subsequently are attached to other components to complete assemblies. For example, on assembly lines for automobiles, many different preassembled components are arranged and installed to complete the automobile. Some preassemblies are complex having many parts attached to one another and ultimately installed in the final assembly.
Some systems of an automobile, for example, require many individual parts that are installed in succession, and which cooperated with one another but do not attach securely to each other until the final assembly is complete. For example, in automobile suspension systems a connection between a suspension arm and rod may include the rod passing through a hole in the arm with fasteners, washers, grommets, spacers and the like on each side of the arm. The installation of each individual piece during final assembly of the automobile can be complex and time consuming. If assembled in a wrong order, or with one part missing the assembly will not work correctly. Nuts, grommets, washers and the like can be difficult to handle individually as discrete parts, slowing final assembly.
To facilitate final assembly, it is known to group unconnected but adjacent parts together so that an entire group can be installed in a single step. Grommets, nuts, washers and the like may engage each other to some limited degree; however, handling can cause the parts to become dislodged. When the preassembled group of parts is disrupted, the entire group is unusable unless a skilled assembler can properly position the random parts.
Accordingly, it has been known to use shrink wrap surrounding the grouped, pre-assembled parts to secure the relationships between the individual parts in the group. The group is installed in the final assembly with the shrink wrap in tact, and allowed to remain bundled with the shrink wrap after assembly.
For example, in a known prior art group of parts for a vehicle suspension, a grommet and a washer have been grouped alone, or with a nut, spacer or the like, and held together by a shrink wrap sleeve of known material that is installed initially loosely over the parts and subsequently treated, such as by heat, to shrink and fit snugly against the parts, securing the parts together. In a final assembly, a group of a grommet and a washer with a shrink wrap sleeve in tact is placed on a rod and against a shoulder. A suspension arm is positioned also on the rod and against the group. Thereafter, a second group of a grommet a washer and a nut with its shrink wrap sleeve in tact is positioned against the arm, and the nut is rotated to engage threads on the rod to secure the final assembly in proper position between the shoulder at one end and the nut at the other end.
While groupings of parts such as that described above have worked successfully and advantageously for efficient assembly, to ensure that the shrink wrap sleeves remain in position during handling and installation of the groups of parts so that the parts are not dislodged and lost, the sleeves surround substantial portions of the grommets and other parts, including downwardly sloping ends thereof that come in contact with other parts in the final assembly. As a result, during angular movement of a joint formed by the parts, as the parts move and twist at various angles relative to each other, the shrink wrap sleeves can be pinched between opposed surfaces of the arm and grommets or other parts initially held by the shrink wrapped sleeve. With continued angular movement, continuous or intermittent rubbing of the shrink wrap sleeves between the parts can cause unacceptable noise, and even a mistaken presumption of failing or improperly working parts. However, due to the smooth outer surface and shape of the grommet, if the downward sloping surface of the grommet is not wrapped by the sleeve, the sleeve can slide off the grommet, resulting in the group becoming unusable.
Accordingly, it is desirable to provide a means for using shrink wrap to hold otherwise loose parts in proper sequence and position, without causing subsequent interference with the cooperating parts.

SUMMARY OF THE INVENTION

The present invention provides shrink wrap retaining or anchoring features on one or more of the parts, such as the grommet to provide an anchor against which the shrink wrap can constrict, with the anchors and shrink wrap positioned away from contact surfaces in the final assembly.
In one aspect thereof, the present invention provides a group of parts with at least a first part, a loosely associated second part and a shrink wrap sleeve encircling the parts. At least one of the parts has at least one shrink wrap anchor in the form of an abrupt diameter transition on an outer surface against which the shrink wrap sleeve is constricted for holding the first and second parts in position relative to one another.
In another aspect thereof, the present invention provides a grommet with a grommet body having a first end, a second end and a substantially smooth outer surface. The first end is configured for engagement against another part in use. Shrink wrap anchors spaced from the first end are provided for anchoring a shrink wrap sleeve remote from the first end.
In a still further aspect thereof, the present invention provides a grommet assembly with a grommet, a second part held against an end of the grommet and a shrink wrap sleeve encircling the grommet and the second part. The shrink wrap sleeve is constricted against the second part. At least one shrink wrap anchor is provided on the outer surface of the grommet, and forms an abrupt transition in diameter of the grommet near the end of the grommet. The sleeve is constricted against the at least one sleeve anchor. An opposite end of the grommet is uncovered by the sleeve.
An advantage of the present invention is providing a structure whereby a minimal amount of shrink wrap can be used for holding otherwise loose parts together without enveloping the entire group of parts completely.
Another advantage of the present invention is providing structure whereby shrink wrap can be used to group otherwise loose parts together whereby the shrink wrap can be held away from surface areas of the parts that are contact surfaces in a final assembly.
Still another advantage of the present invention is providing structure whereby shrink wrap can be used to group otherwise loose parts and whereby the shrink wrap can be removed easily after final assembly, if desired.
Other features and advantages of the invention will become apparent to those skilled in the art upon review of the following detailed description, claims and drawings in which like numerals are used to designate like features.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is an elevational view of a grouped assembly of parts in accordance with the present invention;
FIG. 2 is an end view of the grommet assembly shown in FIG. 1;
FIG. 3 is an elevational view similar to that of FIG. 1, but illustrating a second embodiment of the present invention;
FIG. 4 is an end view similar to that of FIG. 2, but illustrating the embodiment of FIG. 3; and
FIG. 5 is an elevational view of an assembly having two groups of parts in accordance with the present invention.
Before the embodiments of the invention are explained in detail, it is to be understood that the invention is not limited in its application to the details of construction and the arrangements of the components set forth in the following description or illustrated in the drawings. The invention is capable of other embodiments and of being practiced or being carried out in various ways. Also, it is understood that the phraseology and terminology used herein are for the purpose of description and should not be regarded as limiting. The use herein of “including”, “comprising” and variations thereof is meant to encompass the items listed thereafter and equivalents thereof, as well as additional items and equivalents thereof.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT

Referring now more specifically to the drawings and to FIG. 5 in particular, an assembly 10 is shown having a first group of parts 12 and a second group of parts 14, each of the groups of parts 12 and 14 being preassembled in accordance with the present invention. Groups of parts 12 and 14 are first and second grommet subassemblies mounted on a rod 16 which also engages an arm 18, with groups 12 and 14 on opposite sides of arm 18. As depicted, assembly 10 can be a portion of a vehicle suspension system; however, it should be understood that the present invention can be used for groups of parts in other types of suspension systems, in automobile systems other than suspensions systems and for assemblies other than automobiles.
With reference now to FIG. 1, group 12 is shown. Group 12 is an outer grommet subassembly and includes a grommet 20 being a body having a substantially smooth outer surface 22. A washer 24 and a nut 26 are provided at one end of grommet 20. Nut 26 can be attached to washer 24 or loosely associated therewith for rotation thereagainst. Nut 26 also can be connected to a spacer or sleeve-like extension 28 extending through grommet 20. Grommet 20 is provided with a sloping first end surface, generally designated by numeral 30, which is held against arm 18 in assembly 10 and thereby is a contact surface of grommet 20 against arm 18. As relative movement occurs between grommet 20 and arm 18, the area of contact against end surface 30 changes. Grommet 20 has a second end 32 opposite first end 30. Second end 32 is adjacent washer 24 and nut 26.
A sleeve 34 is provided to group and secure the associated parts of grommet 20, washer 24 and nut 26. Sleeve 34, designated by a line in FIG. 1, surrounds the associated parts, or at least a portion thereof, encircling washer 24 and the end portion of grommet 20 adjacent washer 24. Sleeve 34 is a shrinkable film that can be applied loosely and thereafter shrunk to lie tightly along and over the surfaces it covers. Suitable shrinkable films are known for many uses and purposes. Upon activation, such as by heat, the film constricts tightly. Since the film conforms closely against even irregular surfaces, otherwise nonconnected parts can be held together securely.
If shrink wrap substantially surrounds and envelopes things to be held thereby, the shrink wrap remains in place securely. Relative movement between a shrink wrap package and a substantially smooth surface can occur, particularly if the shrink wrap terminates on a major diameter of the smooth surfaced object.
Accordingly, in part groups such as group 12, it has been known to envelope the grommet and the other parts, including substantially end face surfaces of the outer most parts, including end surface 30 of grommet 20, so that shrinkage of film 34 applies axial force against the outermost parts to secure the relative positions of the parts with respect to one another.
Grommet 20 is provided with an anchoring fixture or structure in the form of an annular ring 40 projecting outwardly from surface 22 remote from end surface 30. Ring 40 in the exemplary embodiment is nearer to second end 32 than to first end 30. Ring 40 defines an abrupt diameter transition on surface 22 against which the shrink wrap sleeve 34 can constrict. In the exemplary embodiment, ring 40 defines an overall major or largest diameter of grommet 20.
Sleeve 34 extends just beyond ring 40, only minimally toward end surface 30. However, a terminal edge 42 of sleeve 34 is held securely in position on grommet 20, being anchored by ring 40 against which sleeve 34 constricts. Sleeve 34 is retained well away from portions of surface 30 that contact arm 18 during angulations of the completed assembly.
Group 14 (FIG. 5) is similar to group 12, and similar components thereof are identified with the same numerals as the corresponding components in group 12. Essentially, group 14 includes a second grommet 20, a second washer 24 and a second shrink wrap sleeve 34 there around. However, being an inner grommet subassembly, second group 14 does not include a nut 26.
FIGS. 3 and 4 illustrate a variation of the previously described grommet 20. A grommet 50 has a substantially smooth outer surface 52 and includes a plurality of dimples or bumps 54 arranged spaced from a curved end surface 56 of grommet 50 which is a contact surface against arm 18 after installation. In FIGS. 3 and 4, four dimples 54 are shown, although more or fewer dimples 54 can be used. Dimples 54 serve as anchors for and cooperate with a shrink wrap sleeve 58 to retain sleeve 58 on the group of parts, but with an edge 60 of sleeve 58 well away from the portions of surface 56 that may contact arm 30 after installation. Again, a terminal portion of sleeve 58 surrounds each dimple 54 and is anchored there against to hold sleeve 58 securely on grommet 50.
Grommets 20 and 50 have substantially smooth outer surfaces, 22 and 52, respectively, except for ring 40 and dimples 54 that project outwardly therefrom as abrupt changes in diameter. The use of outward projections or anchors, such as dimples 54 or annular ring 40, allows the use of shrink wrap sleeves 34, 58 that are of short axial length, and that are held well away from the areas of end surfaces 30, 56 that may contact arm 18. Shrink wrap sleeves 34 and 58 are held away from and not located where the sleeves can be pinched between grommets 20, 50 and arm 18, thereby eliminating noise and mistaken interpretations of defective operation from noise generated by pinching and rubbing against the sleeves.
It should be understood that a variety of shrink wrap retaining configurations other than dimples 54 and annular rings 22 can be used to secure the positioning of the shrink wrap sleeve. Dimples 54 and annular rings 22 are merely two exemplary anchoring structures that create abrupt diameter transitions of increasing diameter. However, anchoring structures defining abrupt diameter transitions also can be abruptly decreased diameters. Accordingly, inward depressions or a channel also could be used to provide regions in which inward constriction of the shrink wrap can occur, thereby securing the shrink wrap in place and securing the group of parts. A plurality of discontinuous segments can be used, rather than a continuous ring 40. Dimples of various shapes can be used. The present invention can be used on outer parts of large part groups as well as various intermediate parts within part groups. The invention can be used for large groups having many individual parts, as well as on relatively small groups of parts as shown. While shown for use with grommets and parts such as washers, nuts and spacers, the present invention can be used also for first and second loosely associated parts of other types.
In assembly 10, rod 16 is inserted through second group 14, and washer 24 abuts a shoulder (not shown) on rod 16 to limit further axial movement thereon. Rod 16 is inserted through arm 18, and first group 12 is then installed on rod 16, against the opposite side of arm 18 from group 14. Nut 26 is rotated to engage a threaded end (not shown) of rod 16. As can be seen clearly from the illustration of FIG. 5, sleeves 34 are held well away from any pinch points that might occur between arm 18 and grommets 20 and 50.
Variations and modifications of the foregoing are within the scope of the present invention. It is understood that the invention disclosed and defined herein extends to all alternative combinations of two or more of the individual features mentioned or evident from the text and/or drawings. All of these different combinations constitute various alternative aspects of the present invention. The embodiments described herein explain the best modes known for practicing the invention and will enable others skilled in the art to utilize the invention. The claims are to be construed to include alternative embodiments to the extent permitted by the prior art.
Various features of the invention are set forth in the following claims.

Claims

1. A group of parts comprising:

at least a first part and a loosely associated second part;

a shrink wrap sleeve encircling said parts; and

at least one said part having at least one shrink wrap anchor in the form of an abrupt diameter transition on an outer surface against which said shrink wrap sleeve is constricted for holding said first and second parts in position relative to one another.

2. The group of parts of claim 1, said shrink wrap anchor comprising an outwardly extending ring surrounding one of said parts.

3. The group of parts of claim 1, said shrink wrap anchor comprising a plurality of outwardly projecting dimples on at least one said part.

4. The group of parts of claim 1, one said part comprising a grommet, said grommet having an outwardly projecting ring surrounding said grommet, said ring comprising at least one said shrink wrap anchor.

5. The group of parts of claim 1, at least one said part comprising a grommet, and said grommet having a plurality of outwardly projecting dimples, and said dimples comprising shrink wrap anchors.

6. The group of parts of claim 1, at least one said part comprising a grommet, and said grommet having a substantially smooth outer surface and a projection on said outer surface defining an abrupt diameter transition, and said sleeve having a terminal edge near said transition.

7. The group of parts of claim 6, said grommet having an end surface, and said terminal edge of said the sleeve being disposed remote from said and surface.

8. A grommet comprising:

a grommet body having a first end, a second end and a substantially smooth outer surface;

said first end configured for engagement against another part in use; and

a shrink wrap anchor spaced from said first end for anchoring a shrink wrap sleeve remote from said first end.

9. The grommet of claim 8, said shrink wrap anchor comprising an outwardly projecting ring surrounding said grommet.

10. The grommet assembly of claim 8, said shrink wrap anchor comprising a plurality of outwardly projecting dimples.

11. The grommet assembly of claim 8, said shrink wrap anchor comprising an abrupt diameter transition.

12. The grommet assembly of claim 1, said abrupt diameter transition being of abrupt increasing diameter.

13. A grommet assembly comprising:

a grommet;

a second part held against an end of said grommet;

a shrink wrap sleeve encircling said grommet and said second part, said shrink wrap sleeve being constricted against said second part;

at least one shrink wrap anchor on an outer surface of said grommet, said anchor comprising an abrupt transition in diameter of said grommet near said end of said grommet, and said sleeve and being constricted against said at least one shrink wrap anchor; and

an opposite end of said grommet being not covered by said sleeve.

14. The grommet assembly of claim 13, said at least one shrink wrap anchor comprising an outwardly extending ring surrounding said grommet.

15. The grommet assembly of claim 13, said at least one shrink wrap anchor comprising a plurality of outwardly projecting dimples on said grommet.

16. The grommet assembly of claim 13, said abrupt transition being a transition of increasing diameter.

17. The grommet assembly of claim 13, said at least one shrink wrap anchor being discontinuous.

18. The grommet assembly of claim 13, said second part being one of a washer, a spacer and a nut.

19. The grommet assembly of claim 18, said abrupt transition being a transition of increasing diameter.

20. The grommet assembly of claim 13, said abrupt transition defining a major diameter of said grommet.