Method of applying applique or like object to a baseplate

Applique or similar object is simultaneously formed and affixed to a baseplate by juxtaposing a plate of contributing material adjacent the baseplate and forcing a punch entirely through the contributing material to shear the object from the plate of contributing material. The object, in turn, shears a slug from the baseplate, which is positioned against a die opening, forming an opening in the baseplate in which the object is retained by interference fit. The method may be used to affix objects from a contributing material that is either harder than or softer than the baseplate material.

BACKGROUND OF THE INVENTION 
This invention relates to a method for manufacturing a composite article 
and in particular to such method including forming an object such as 
applique and attaching such object to a baseplate. 
Applying applique, such as clock time marks, to a baseplate, such as the 
time ring of a clock face, is difficult at best. One approach has been to 
stamp the applique from a material of desired finish and color and to 
apply the applique to a baseplate of desired finish and color. An adhesive 
is applied to the back surface of the applique pieces which are 
individually aligned in a jig and then brought into engagement with the 
baseplate. Minute burrs on the backside of the applique tend to interfere 
with adequate adhesion to the baseplate resulting in occasional failure of 
the adhesive. 
One proposed alternate is to form the applique of a substantially harder 
material than the baseplate and including pins extending rearwardly from 
the applique. The applique is applied to the baseplate by positioning 
individual applique pieces in a jig or the like and pressing the baseplate 
against the back of the applique so as to force the pins through the 
baseplate which retains the pins by frictional engagement. The difficulty 
with this approach is that the choice of materials is limited and must be 
different for the applique and the baseplate. Additionally, the applique 
must be preformed and prearranged in the jig prior to application to the 
baseplate. 
Accordingly, it is an object of the present invention to overcome the 
difficulties of the prior art. 
SUMMARY OF THE INVENTION 
An object, such as applique, is applied to a baseplate by juxtaposing a 
plate of contributing material adjacent the baseplate and positioning the 
juxtaposed plates between a punch and die configured to the shape of the 
desired object. The punch is forced entirely through the contributing 
material to shear the object from the plate of contributing material. The 
object in turn shears a slug from the baseplate forming an opening in the 
baseplate in which the object is retained by interference fit. The 
resulting composite article includes an opening in the baseplate having a 
configuration of the attached object and the object retained in the 
opening by an interference fit developed between the object and the 
surface of the opening. 
The invention provides a surprisingly attractive appearance and an 
exceptionally tight retention force between the object and the baseplate. 
Further, materials having a wide range of hardness may be used for both 
the baseplate and the contributing plate thus allowing a large choice of 
materials as well as potential for use in many applications. 
When the invention is used to apply applique, such as time marks, to a time 
ring, the use of jigs to position the individual figures is eliminated 
because the applique is formed and affixed to the baseplate in the same 
step. 
These and other related objects, advantages and features of this invention 
will become apparent upon review of the following specification in 
conjunction with the drawings.

BRIEF DESCRIPTION OF THE PREFERRED EMBODIMENT 
Referring now specifically to the drawings, and the illustrative 
embodiments depicted therein, a composite article 10 is illustrated as a 
portion of a time ring of a clock face including a baseplate 12 and an 
object 14 attached to the baseplate. In the illustrative embodiment the 
attached object is a time mark, such as the numeral "2" portion of the 
number "12", on the time ring. Such an object affixed to a baseplate is 
referred to as applique. 
As illustrated in FIG. 2, object 14 is positioned within an opening 16 in 
baseplate 12. Opening 16 extends entirely through the thickness of the 
baseplate and has substantially the same configuration as the object. The 
illustrated object includes an outer surface 18 projecting beyond the 
outer surface 20 of baseplate 12. Object 14 further includes perimeter 
surface 22 which firmly engages the surface of baseplate 12 that defines 
opening 16 by an interference fit, in a manner that will be explained 
below. Object 14 further includes an inner surface 24. 
In order to form object 14 and opening 16 in baseplate 12 and to firmly 
position the object within opening 16, a sheet of contributing material 26 
is juxtaposed with baseplate 12. The juxtaposed plates are then positioned 
on a die 28 with the baseplate facing the die. Die 28 includes a pierce 
opening 30 configured substantially to the shape of the desired object. A 
punch 32, also of substantially the same configuration as the desired 
object 14, is forced by a press or the like into and through the plate 26 
shearing a slug 34 from the plate. Slug 34 progresses into baseplate 12 
acting as a punch to shear a scrap slug 36 from baseplate 12. The movement 
of punch 32 is terminated after a stroke predetermined to position slug 34 
in a desired relationship to baseplate 12. Slug 36 and the remains of 
plate 26 are discarded as scrap or recycled. 
Slug 34 forms an interference fit with baseplate 12 because it has a 
diameter greater than that of the opening 16 formed in baseplate 12 by the 
slug. The reason for this phenomenon is that slug 34 breaks out of 
material 26 with a positive breakout angle .alpha. causing it to have a 
diameter larger than the diameter d.sub.2 of punch 32. Although slug 34 
punches opening 16 in baseplate 12, the diameter of opening 16 is more 
closely related to diameter d.sub.1 of pierce opening 30. Thus, taking the 
example where d.sub.1 is equal to d.sub.2, the positive breakout angle 
.alpha. will cause slug 34 to be larger than d.sub.2 while opening 16 is 
very close in diameter to d.sub.1. Thus, the diameter of slug 34 will be 
larger than opening 16 with the result that slug 34 will be retained in 
opening 16 with an interference fit. 
As punch 32 presses on inner surface 24 of slug 34, deformation of this 
surface occurs. The only direction for the deformed metal to flow is 
outwardly. This creates a barb 40 extending radially outwardly from 
surface 24. This barb embeds into the surface of opening 16 and prevents 
object 14 from being forced out of opening 16. If diameter d.sub.1 of 
pierce opening 30 is preselected to be either substantially the same as 
diameter d.sub.2 of punch 32, or less than the diameter d.sub.2 of punch 
32 (negative die clearance), a second radially extending burr 42 is formed 
around the perimeter of outer surface 18. Burr 42 is formed by the action 
of slug 34 being forced within pierce opening 30, which is smaller than 
the diameter of the slug. Burr 42 engages outer surface 20 of baseplate 12 
and restrains object 14 from being ejected rearwardly out of opening 16. 
Thus, it is seen that appropriate selection of the diameters of punch 32 
and die 28 allows control of the interface between the applique and the 
baseplate to adjust the retaining force. If the diameter d.sub.1 of pierce 
opening 30 is preselected to be much smaller than diameter d.sub.2 of 
punch 32, the outer surface 20 of baseplate 12 will tend to become 
somewhat deformed adjacent the applique. In many applications, the 
enhanced retention strength is not worth the deformation of the baseplate. 
In one embodiment, baseplate 12 and contributing material 26 are both 
0.050" thick aluminum and d.sub.1 is greater than d.sub.2 by approximately 
0.0005" (positive die clearance). This provides a smooth and slightly 
rounded surface 18 with negligible deformation of surface 20. Object 14 is 
retained in opening 16 with such strength that it is not readily removable 
by hand. By adjusting the thickness of baseplate 12 and the stroke of 
punch 32, outer surface 18 of object 14 can be positioned either flush 
with, extending from or even recessed within baseplate 12. If recessed 
within, then an additional step of removal of scrap slug 36 may be 
required. 
An embodiment of an apparatus for performing the process of the invention 
is illustrated in FIG. 4. Apparatus generally shown at 44 includes an 
upper shoe 46 and lower shoe 48 of a press, which are selectively forced 
together by a ram (not shown). An upper die assembly 50, associated with 
upper shoe 46, includes a retainer 52 attached to upper shoe 46 and a 
retainer 54 attached to retainer 52. A cylindrically-shaped opening in 
retainer 54 accommodates an outer pierce bushing 56 and a stamp bushing 58 
concentrically received within an opening in pierce bushing 56. A pierce 
punch 60 extends from upper shoe 46 through aligned cylindrical openings 
in retainer 52 and stamp bushing 58. Pierce bushing 56 and pierce punch 60 
are mounted in a manner that no relative movement with respect to upper 
shoe 46 is provided. In contrast, a gap 62 is provided between an upper 
portion of stamp bushing 58 and pierce bushing 56 to allow a limited 
amount of longitudinal movement between these members. An ejector pin 64 
extends through aligned openings in retainer 52 and upper shoe 46 and into 
engagement with stamp bushing 58. Ejector pin 64 is biased downwardly by 
an ejector spring 66 to place a downward spring bias on stamp bushing 58. 
A lower die assembly 68 includes a pierce bushing 70 rigidly held to lower 
shoe 48 by a retainer 72. A spring pad 74 surrounds pierce bushing 70 and 
axially reciprocates with respect to bushing 70. Spring pad 74 is biased 
away from lower shoe 48 by a die spring 76 and is nonrotatably retained in 
alignment with lower shoe 48 by a spool 78. 
The apparatus 44 is illustrated in FIG. 4, forming a complex article having 
an affixed object that includes an uninterrupted perimeter of such 
contributing material retained by the baseplate and a portion of the 
baseplate retained within the contributing material. An example of an 
affixed object is the numeral "0". Apparatus 44 is illustrated in FIG. 4 
in the end of its travel, forming article 10 including object 14 from 
baseplate 12 and contributing material 26. Pierce bushing 70 functions as 
the punch extending through contributing material 26 and partially through 
baseplate 12. Bushing 70 is received in a die opening defined between 
pierce bushing 56 and pierce punch 60. Stamp bushing 58 optionally serves 
as a coining member, stamping newly-formed surface 18 of object 14 to 
remove any bowing of the surface that may result from the forming process. 
Stamp bushing 58 additionally serves the function of properly spacing 
pierce punch 60 from pierce bushing 56. By reference to FIG. 5a, bushing 
58 is free to move upwardly during the initial portion of the process but 
abuts retainer 52 at a terminal point of the process to perform the 
coining operation. Therefore, if the coining operation is not desired, 
then stamp bushing 58 would be shorter in length to provide clearance 
between its lower surface and the outer surface 18 of object 14. 
As the upper and lower shoes are separated, ejector pin 64 forces stamp 
bushing 58 downwardly which ejects object 14 from the die opening between 
pierce punch 60 and pierce bushing 56 to separate the article 10 from 
upper die assembly 50. Likewise, die spring 76 forces spring pad 74 
upwardly to separate pierce bushing 70 from baseplate 12. The baseplate 12 
and contributing material 26 are then removed from apparatus 44 with the 
contributing material 26 and scrapped slug 36 discarded as scrap or 
recycled. 
In the illustrated embodiment, the particular orientation of the upper and 
lower dies is preselected to allow the plate material to be fed into and 
removed from the die in a manner that any abrasion will occur on the 
contributing material 26, which is scrap, rather than on the front surface 
20 of baseplate 12, which is the finished surface. Thus, contributing 
material 26 is oriented below baseplate 12 where it will receive the wear 
and tear from loading and unloading the die. Because the leftover 
contributing material 26 is scrap, it may be desirable to provide means 
(not shown) to index contributing material 26 with respect to baseplate 12 
between applique operations in order to utilize more portions of material 
26 and thus minimize scrap. 
The present invention is capable of affixing objects to baseplates from a 
wide range of materials. Besides the application of an aluminum object to 
an aluminum base, the invention is capable of affixing an aluminum object 
to a steel base, a steel object to an aluminum base and a steel object to 
a steel base. Thus, it is seen that the invention is not limited to a 
particular hardness relationship between the baseplate material and the 
contributing material. This ability to use a much softer contributing 
material with a relatively harder baseplate material allows the 
application of objects made from polymeric plastics such as LEXAN.TM. 
plastic to an aluminum baseplate. This application is exceptionally useful 
for creating applique that is capable of backlighting. Thus, if the 
applique is of a translucent LEXAN plastic and is affixed to an aluminum 
baseplate, an illuminating source behind the baseplate will illuminate the 
applique, which is referred to as positive backlighting. Conversely, it 
has been discovered that aluminum contributing material may be utilized to 
affix applique to a polymeric plastic baseplate material such as 
translucent LEXAN plastic. In this application, the applique is opaque and 
the baseplate is translucent. The resulting complex article is suitable 
for negative backlighting by the positioning of a light source behind the 
baseplate to illuminate the baseplate but not the applique. Furthermore, 
the invention is suitable for affixing polymeric plastic object to a 
polymeric baseplate which promises a host of potential applications. 
Furthermore, it has been discovered that the invention is adaptable to 
applying a particular pattern or finish, such as lines 80b (FIG. 6b) on 
the applique or object by supplying a baseplate material having the 
corresponding pattern or finish, such as lines 80a (FIG. 6a) formed in the 
surface that is engaged with the contributing material plate during the 
process. The process creates a large surface engagement force between the 
engaging surfaces of the baseplate and contributing material sufficient to 
transfer the pattern to the outer surface of the applique. 
The invention has application beyond the decorating of articles such as 
clock faces. For example, an object such as an isolated electrical contact 
may be attached to a baseplate by utilizing the apparatus illustrated in 
FIG. 4 with a metal baseplate, such as copper, and an electrically 
insulating contributing material, such as LEXAN plastic. The centermost 
portion of the object will be a circular portion of the metal baseplate 
material retained within an "O" or doughnut object of insulating material 
which is, in turn, affixed to the baseplate. In this manner, the portion 
retained by the insulating material is firmly retained mechanically to the 
baseplate but electrically isolated therefrom. 
One skilled in the art could preselect the thickness of the baseplate and 
contributing material and the throw of the die pieces in order to provide 
an inset, a flush or a raised applique or object with respect to the 
baseplate. The process will accommodate vastly different finishes, colors 
and material thickness and compositions. Other changes and modifications 
in the specifically described embodiments can be carried out without 
departing from the principles of the invention which is intended to be 
limited only by the scope of the appended claims, as interpreted according 
to the principles of patent law including the doctrine of equivalents.