Patent Publication Number: US-7723626-B2

Title: Haptics cone

Description:
BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     This invention relates to a push button assembly, and more particularly, a push button assembly having drawer slide guides. 
     2. Description of Related Art 
     Push buttons are used to control a wide variety of electronic equipment, including electronic equipment within automobiles. Examples of such uses are buttons for audio applications, driver&#39;s information applications, climate control, four-wheel drive activation/deactivation, door switches, and seat movement applications, to name a few. 
     Push buttons having a transparent or translucent display portion on the front surface are known in the art. These types of push buttons have a light guiding portion, called the button retainer, extending from the back of the push button and extending through a bezel structure. Often, multiple drawer slide guides protrude from the side of the button retainer in order to control friction and wobble. 
     Button retainers and bezel structures of the type herein are generally made of plastic and injection molded from steel molds. In order to minimize both the friction between the button retainer and the bezel structure and the wobble of the button retainer within the bezel structure, the button retainer and corresponding bezel structure must meet accurate tolerances. Often, as friction is decreased, wobble increases, and vice versa. 
     In addition to controlling friction and wobble, button design also involves maximizing the lightable area, minimizing the gap between the button retainer and the bezel structure, ensuring adequate button travel, and maximizing the durability of the button assembly. Attempting to satisfy all of these design parameters causes a button to become over-constrained. 
     A bezel structure is often tuned to fit a button retainer by a process that involves cutting the mold for the bezel structure to one side of a predetermined tolerance band, leaving gaps for the drawer slide guides of the button retainer. Next, the bezel structure is injection molded, and the button retainer is fit within the bezel structure. Measurements are made for adjusting the bezel mold to fit the button guides to accurate tolerances. Then, the bezel mold is re-cut or material is added to the bezel mold. Tuning the multiple drawer slide guides in three dimensions along multiple axes is difficult to control and difficult to package, especially now that bezel structures are designed with computers. 
     In view of the above, it is apparent that there exists a need for a button retainer and bezel that meet design demands from both a friction and a wobble standpoint. Furthermore, there exists a need for a button retainer and bezel structure in which tuning the button retainer to fit within the bezel structure is easier to control and more accurate. 
     BRIEF SUMMARY OF THE INVENTION 
     The present invention provides a button retainer and bezel structure having a single contact point. The single contact point helps control wobble without substantially increasing friction and helps reduce or eliminate rattle noise during vibration. The tuning process may also be simplified. The present invention provides a process that may be used to create the button retainer and bezel structure, allowing time to be saved in the tuning process. 
     A push button assembly is provided, which includes a button retainer and a corresponding bezel structure. The button retainer has a first drawer slide guide disposed along a first plane, the first plane being parallel to a principal translational axis of the button retainer, and a second drawer slide guide disposed along a second plane, the second plane being parallel to the principal translational axis of the button retainer and perpendicular to the first plane. A surface is disposed along a third plane, the third plane being perpendicular to the first and second planes and the principal translational axis. A conical protrusion extends from the surface. The conical protrusion includes an outer conical side having a perimeter. The bezel structure has a plurality corresponding surfaces, and each corresponding surface is mated with one of the first and second drawer slide guides. The bezel structure also has portions forming a conical indentation. The portions forming the conical indentation include an inner conical side having a perimeter. The outer conical side of the button retainer is configured to mate with the inner conical side of the bezel structure in a pre-load position, such that the outer and inner conical sides contact each other around their perimeters. In a depressed position, the conical protrusion is configured to move away from the portions forming the conical indentation. 
     In another embodiment, the conical protrusion is formed as part of the bezel structure, and the portions forming the conical indentation are formed as part of the button retainer. 
     In yet other embodiments, the protrusion has an elliptical shape and corresponds to portions forming an elliptical indention. 
     In another aspect, a method of producing a button assembly, such as a push button assembly or hinge button assembly, is provided. The method includes providing an attachment pair, which includes a cone mold pin and a corresponding conical pocket pin, at one side of a predetermined tolerance band for use with one of a retainer mold and a bezel mold. A retainer mold for molding a button retainer and a bezel mold for molding a bezel structure are provided, each having an aperture for attaching one of the attachment pair. One of the attachment pair is attached within each aperture. Then, the button retainer is molded from the retainer mold, and the bezel structure is molded from the bezel mold, which produces a molded piece that includes a conical protrusion having an outer conical side with an outer perimeter and a molded piece that includes corresponding portions forming a conical indentation having an inner conical side with an inner perimeter. The method then involves fitting the conical protrusion within the corresponding conical indentation and determining whether the outer conical side contacts the inner conical side around the perimeters of each of the inner and outer conical sides. If the inner and outer conical sides do not contact each other around their perimeters, the method involves altering at least one component of the attachment pair, reattaching the component of the attachment pair to at least one of the retainer mold and the bezel mold, and remolding at least one of the button retainer and the bezel structure. The method involves continuing to: 1) alter at least one component of the attachment pair, 2) reattach the component of the attachment pair to at least one of the retainer mold and the bezel structure, and 3) remold at least one of the button retainer and the bezel structure until the inner and outer conical sides contact each other around their perimeters. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is an exploded view of a push button assembly embodying the principles of the present invention; and 
         FIG. 2  is cross-sectional view of the push button assembly of  FIG. 1 . 
     
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     The present invention provides a novel and nonobvious push button assembly that allows wobble to be controlled to a tight tolerance while the button is under pre-load, while allowing the button to move freely when the button is depressed. The present invention also provides a novel and nonobvious process that simplifies the molding tools for a push button assembly, thereby reducing lead times and costs. 
     With reference to  FIG. 1 , a push button assembly is provided and generally indicated at  10 . The push button assembly  10  includes a button retainer  12  and a corresponding bezel structure  14 . The button retainer  12  has a plurality of drawer slide guides  16 . The bezel structure  14  may also have drawer slide guides  18 . The drawer slide guides  16 ,  18  are generally disposed along multiple planes that are perpendicular to each other, while each still runs parallel to a principal axis of translational motion X. As shown in  FIG. 1 , the button retainer  12  is oriented ninety (90) degrees from the principal axis of translational motion X in order to show the features of the button retainer  12 , but it should be understood that the button retainer  12  is configured to mate with the bezel structure  14  and slide along the principal axis of translational motion X. 
     The bezel structure  14  has a plurality of corresponding surfaces  20  that mate with the drawer slide guides  16 . Likewise, the button retainer  12  has corresponding surfaces  22  to mate with the drawer slide guides  18  of the bezel structure  14 . It should be understood that, in the alternative, the drawer slide guides  16 ,  18  and the corresponding surfaces  20 ,  22  could be provided on only one of the button retainer  12  and bezel structure  14 , instead of each being provided on both. 
     The button retainer  12  has a surface  24  that is disposed perpendicular to the principal axis of translational motion X. In the embodiment of  FIG. 1 , a conical protrusion  26  extends from the surface  24 . The conical protrusion  26  includes an outer conical side  28  having a perimeter extending around the conical protrusion  24 . Preferably, the conical protrusion  26  has a cone angle in the range of 20 to 30 degrees; however, it is contemplated that the conical protrusion  26  could have other cone angles without falling beyond the spirit and scope of the present invention. 
     The bezel structure  14  has portions  30  forming a conical indentation. The portions  30  forming the conical indentation include an inner conical side  32  that has an inner perimeter extending around its inside. 
     The outer conical side  28  is configured to mate with the inner conical side  32  in a pre-load position. In other words, when the button retainer  12  is slid into the bezel structure  14 , a pre-load force is exerted upon the button retainer  12 , which holds the button retainer to the bezel structure  14 . In one embodiment, this pre-load force may be accomplished by utilizing switchmat domes (not shown) on a rear side  34  of the button retainer  12 . The switchmat domes contain electrical contacts to activate a desired function, and they also exert a spring force on the rear side  34  of the button retainer  12  to bias the button retainer  12  toward the bezel structure  14 . The spring force may be approximately three Newtons (3 N), although it should be understood that any suitable spring force may be used. It should be understood by one having skill in the art that the pre-load force may alternatively be exerted through other means, such as tact switches. 
     Thus, in the pre-load position, the outer and inner conical sides  28 ,  32  contact each other around each of their perimeters. With reference to  FIG. 2 , a cross-sectional view of the button retainer  12  and the corresponding bezel structure  14  are illustrated. It may be seen in  FIG. 2  that the inner conical side  32  is in contact with the outer conical side  28  around the diameter, or the perimeter, of each. This provides a limit to the wobble of the button retainer  12  when the button retainer  12  is in the pre-load position. Because wobble is limited in this way, it is not necessary to also tune the drawer slide guides  16 ,  18  and corresponding surfaces  20 ,  22  to extremely tight tolerances. 
     More specifically, it is typical in the art to provide a 0.07 millimeter gap between the drawer slide guides  16 ,  18  and the corresponding surfaces  20 ,  22 . This small gap is desired because a larger gap may provide an excessive amount of wobble; however, such a small gap creates friction, especially when surrounding conditions such as pressure and temperature vary. Because the conical aperture  26  and portions  30  forming the conical indentation limit wobble in the pre-load position, it is acceptable to provide a gap in the range of 0.10 to 0.30 millimeter between the drawer slide guides  16 ,  18  and the corresponding surfaces  20 ,  22 . 
     When the button retainer  12  is depressed, the conical protrusion  26  moves away from the portions  30  forming the conical indentation. Because the gap between the drawer slide guides  16 ,  18  and the corresponding surfaces  20 ,  22  is larger, friction is reduced and the button retainer  12  may be slid along the principal translational axis X in various ambient conditions without encountering an excessive amount of friction. 
     Although the conical protrusion  26  is shown in  FIG. 1  as being located on the surface  24  of the button retainer  12 , it is contemplated by the present invention that, instead, the conical protrusion  26  could be located on the bezel structure  14 . In such an embodiment, the corresponding portions  30  forming the conical indention would be located on the surface  24  or other suitable surface of the button retainer  12 . 
     Furthermore, although the protrusion  26  is illustrated having a conical shape, the protrusion  26  and corresponding portions  30  could alternatively have an elliptical shape. An elliptical protrusion and corresponding portions forming an indentation would provide the added benefit of limiting wobble and twist along multiple axes. 
     The present invention also provides a novel method to tune the button retainer  12  to fit the bezel structure  14  of a push button assembly  10  or a hinge button assembly (not shown). Typical methods of producing button retainers  12  and bezel structures  14  involve Electrode Discharge Machining (EDM), multiple levels of tooling changes, and combinations of welding and CNC machining. The tuning process is complicated due to the extremely tight tolerances that have been desired between the drawer slide guides  16 ,  18  and corresponding surfaces  20 ,  22 . 
     The novel method according to one aspect of the present invention involves providing an attachment pair of molding tools created from standard bar stock or other suitable material. The attachment pair includes a cone mold pin and a corresponding conical pocket pin, which may each be attached to a button retainer mold and a bezel structure mold to form the portions of the button retainer and bezel structure that include the conical protrusion and portions forming the conical indentation. 
     The attachment pair is preferably machined to one side of a predetermined tolerance band from traditional methods, such as a lathe, and attached to the desired mold cavity. The mold cavities, including the bezel mold and the retainer mold, have apertures for attaching one of the attachment pair thereto. The cone mold pin may be attached to the bezel mold for use therewith, and the conical pocket pin may be attached to the retainer mold for use therewith, or vice versa. 
     The button retainer  12  and corresponding bezel structure  14  are molded, preferably by injection molding, and the fit of the conical protrusion  26  within the portions  30  forming the conical indentation are examined to determine whether the perimeters of the inner and outer conical sides  28 ,  32  are in contact with each other around the diameter of each. If the inner and outer conical sides  28 ,  32  do not contact each other around their perimeters, at least one of the attachment pair (the cone mold pin, the conical pocket pin, or both) is removed from the bezel or the retainer mold and altered, preferably by traditional machining methods. After at least one of the attachment pair is altered, it is reattached to the corresponding mold, and at least one of the button retainer  12  and corresponding bezel structure  14  is remolded. This process of tuning the fit of the conical protrusion  26  to the portions  30  forming the conical indentation is repeated until the inner and outer conical sides  28 ,  32  contact each other around their perimeters. 
     As a person skilled in the art will readily appreciate, the above description is meant as an illustration of implementation of the principles of this invention. This description is not intended to limit the scope or application of this invention in that the invention is susceptible to modification, variation, and change without departing from the spirit of this invention, as defined in the following claims.