Method and means of fastening two parts with an internally threaded folded fastener

Two mechanical components are interconnected, for example, the two principal parts of a pedal rod by forming the clevis with a progressive die so that threaded portions are provided on opposite sides of an opening and are formed and shaped strictly by compression without rotation. The work piece is then folded so that the threaded portions are in register and the shaft part of the pedal rod is threaded in place and adjusted to take up the tolerances in the linkage. The two parts are locked together either by crimping, spot welding or by a lock nut, or by joining out of sync thread segments.

BACKGROUND OF THE INVENTION 
1. Field of the Invention 
This invention relates generally to method and means of fastening and more 
specifically to a method and means of interconnecting the two components 
of an automotive pedal rod. 
2. The Prior Art 
In my prior application I disclosed a method of forming threads without 
rotation and interconnecting parts wherein the threaded portions were 
located on the outside surfaces. Reference is made to that application 
Ser. No. 07/712,554 now U.S. Pat. No. 5,228,818 filed Jun. 10, 1991 and 
the prior art cited therein for the establishment of the state of the 
prior art. 
SUMMARY OF THE INVENTION 
The present invention exploits the cost saving techniques of automated 
production in order to produce an assembly that exhibits precise 
tolerances and great accuracy. 
First of all, a strip form material is blanked out on a progressive die to 
form a generally elongated rectangular blank or work piece having three 
apertures disposed at opposite ends and at an intermediate position. The 
ends are trimmed to eliminate sharp corners. 
The progressive die also forms a threaded part by compression, and without 
rotation in two longitudinally spaced locations on opposite sides of the 
centermost hole or opening, whereupon the blanked out part is folded back 
upon itself so that opposite leg parts are in alignment with one another. 
Lugs or ears provided on the blank can be alternated on the respective 
legs. 
If the article in question is a pedal rod, as is disclosed by way of 
exemplification of the inventive principles in the present application, 
the folded part can be either a clevis with the two end openings in 
register with one another or the folded together legs can form a simple 
metal arm or rod which is appropriately apertured. 
In the case of a pedal rod, the second part of the assembly is a shaft part 
or element which has an externally threaded portion formed at one end 
which is sized and adapted to be inserted into the clevis and threadedly 
engaged with the internally threaded portion of the folded part. By simple 
threaded adjustment, the two parts can be specifically adjusted to pick up 
all of the tolerances in the linkage, a range which in the average pedal 
rod assembly will be within approximately seventy (70) thousandths of an 
inch. 
When the final adjustment is achieved, the lugs or ears are then turned 
down into the adjoining recesses provided in the folded part and the two 
parts are crimped together or spot welded in firm assembly with one 
another. 
Alternatively, the last step just described can be performed by having the 
pedal rod formed with a generally rectangular configuration as is 
disclosed in my earlier acknowledged prior application and the edges of 
the threaded part of the pedal rod can be provided with two, three, four, 
or five thread portions which are out of sync with threads formed in the 
folded part, or clevis. 
In such an arrangement, the pedal rod is turned into the clevis and with 
the development of at least 5 to 40 inch pounds of torque, the two 
elements of the assembly will remain in permanent firm assembly. However, 
by selectively varying the engagement of a selected number of threads, the 
inch pounds of torque can be correspondingly varied.

DESCRIPTION OF THE PREFERRED EMBODIMENTS AND THE PREFERRED METHODOLOGY 
While the principles of the present invention are applicable to the joinder 
of any two parts, the inventive discoveries find a particularly useful 
application to the manufacture of pedal rods of the type utilized in 
automotive vehicles. Accordingly, an exemplary disclosure is made herein 
to show how the principles of the present invention may be applied to 
pedal rods of different configuration and how a manufacturing process can 
be utilized which advantageously exploits modern mass production 
manufacturing techniques utilizing robots and computerized machinery. 
A typical environment in which a pedal rod is employed in the automobile 
industry is established by a so-called 205 Tandem Recessed Series Zero 
Lost Travel Master VAC shown generally at 20. The device 20 is adapted to 
be actuated by a pedal rod assembly which appears at the right hand side 
of FIG. 1 and is shown at 21. 
Japanese manufacturers generally utilize pedal rods which are of the 
so-called clevis type, whereas American car manufacturers have heretofore 
preferred pedal rods wherein the pedal rod has a simple apertured bar or 
rod. The principles of the present invention are equally applicable to 
both types of pedal rods and the references to one or the other is merely 
intended to be illustrative. 
As shown in FIG. 1, the Master VAC unit 20 has an actuator member 22 which 
is recessed at 23 in a size and configuration to operatively receive and 
engage a ball 24 formed on one end of a first component element of the 
pedal rod 21, namely, the shaft 26. A shoulder 27 is formed on the shaft 
26 for holding a spring retainer associated with a spring 28, the opposite 
end of which is in engagement with parts of the Master VAC assembly 
referred to generally at 29, the details and operation of which are not 
necessary to the understanding of the present invention. 
The shaft component element 26 of the pedal rod 21 is connected at its 
opposite end to a second component element of the pedal rod, namely, the 
clevis 30, or apertured rod, as the case may be. If necessary or desired, 
a lock nut 31 may be utilized in conjunction with the shaft 26 and the 
clevis 30. 
It is with the formation and construction and connection of the two 
component element parts 26 and 30 that the present invention is 
particularly concerned. 
Referring to the series of drawing figures identified as FIG. 6 through 
FIG. 13, the steps of the inventive method will be described. First of 
all, a supply of raw material can take the form of bar stock stored in 
rolls and constituting sheet form material of approximately one eighth 
(1/8) inch in thickness. The material can be fed into a progressive die 
machine of the type having four or five stations and which is controlled 
by automated computerized control programs. 
At a first station, the raw material is initially trimmed to provide a 
first rough blank 40 exhibiting an extra dimensional width which may be 
removed as flashing of approximately one quarter of an inch on each side. 
A generally elongated rectangular blank 41 forming the actual work piece 
is then cut from the rough blank 40 at which stage the blank 41 has end 
walls 42 and 43 which are trimmed or rounded to eliminate sharp corners as 
at 44. A pair of longitudinally extending side walls are formed with legs 
as at 46 and 47 in spaced parallel relation to one another. The leg 46 has 
a notch or recess 48 formed therein and a lug or ear 49 is also formed. 
The opposite leg 47 has a lug or ear 50 formed therein in alignment with 
the recess 48 as well as a notch or recess 51, correspondingly in 
alignment with the lug or ear 49. 
The progressive die is also programmed to cut three holes or openings in 
the blank 41. The first hole or opening is formed inwardly of the end wall 
42 and is shown at 52. At the opposite end, and correspondingly inwardly 
of the end wall 43, there is formed a second hole or opening 53. At 
approximately the midpoint of the blank 41 there is formed a third hole or 
opening 54. 
In accordance with the present invention, the blank is worked at an 
appropriate station of the progressive die to form strictly by vertical 
pressing action and without rotation two longitudinally spaced apart 
threaded portions between and in alignment with the respective recesses 
and ears 48-50 and 49-51. Referring to FIG. 8 of the drawings in 
conjunction with FIG. 9, it will be noted that the leg 46 is bent to form 
a rounded contour 56 with the recess 48 in the center thereof while the 
leg 47 is correspondingly bent to form a rounded contour 57 with the ear 
50 disposed in the center thereof. 
The threaded portions are identified at 60 and 61 and are disposed 
symmetrically on opposite longitudinal sides of the opening 54, thereby 
forming a center apertured zone or area 62. At this stage of the 
manufacturing process, the recesses 48 and 51 and the lugs or ears 49 and 
50 will still be in the relative positions depicted in FIG. 9 of the 
drawings and the formed blank is ready for a folding operation, the 
initial portions of which are depicted in FIG. 10. 
As shown in FIG. 10, the opposite ends of the blank work piece 41 are 
folded on fold lines 63 and 64 at the opposite sides of the center zone or 
area 62. The fold lines 63 and 64 are predetermined in location so that at 
the two legs of the work piece 41 are folded back upon themselves, the 
threaded portions 60 and 61 will be placed in precise mating alignment 
with one another and the ear 50 will be aligned with the recess 51 while 
the ear 49 will be aligned with the recess 48. Further, the apertures 52 
and 53 will also be aligned in register with one another. 
In the formation of a successful pedal rod, it is essential that the device 
exhibit the requisite dimensions to be within prescribed tolerance limits 
as demanded by the automotive manufacturer. Accordingly, in order to pick 
up the tolerances in the linkage, the shaft part or element 21 is now 
preliminarily joined with the work piece 41, which is now in the 
structural configuration of a clevis. 
As is customary in the art, the shaft part 21 is formed with external 
threads as at 70. The dimensions of the shaft part 21 and of the threads 
70 are preselected so that the shaft part is received in the opening 54 in 
the center zone or area 62 of the clevis 41 and threadedly engages the 
threads 60 and 61, now functionally related as a single threaded opening 
in the clevis 41. 
By simple threaded adjustment, the shaft part 21 can be adjusted 
longitudinally relative to the clevis 41 to pick up the tolerances in the 
linkage. It is estimated that the average range of such adjustment may be 
in the order of about seventy thousandths of an inch (0.070"). While such 
adjustment is being effected, the parts of the sub-assembly are in the 
relative positions of FIGS. 11 and 12. Once such adjustment is achieved, 
the lugs or ears 49 and 50 are turned down into the respective adjoining 
recesses 48 and 51, whereupon the two component parts 21 and 41 can be 
crimped into permanent firm assembly with one another in the manner 
depicted in FIG. 13. Spot welding could also be employed. Hence, the 
assembly can be secured by either crimping or spot welding, or both. While 
not essential to the practice of the invention, if deemed necessary or 
desirable, the lock nut 31 may be turned against the zone or area 62 to 
further insure the locked together integrity of the two parts. 
An alternative is contemplated in accordance with the principles of the 
present invention by utilizing the improvements already described in 
conjunction with the improvements of my prior acknowledged application. 
Thus, as shown in FIG. 14, the relative threat segments can be selectively 
made out of synchronization and in variable combining numbers of joining 
threads so that the inch pounds of torque necessary to disconnect the 
joint may be preselected. 
The last step of the process described above is varied in practicing this 
alternative by providing a shaft part 121 having edges formed with thread 
segments 170. The thread segments 170 can be provided with two, three, 
four, or five thread portions which are out of sync with the threads in 
the clevis 41. 
By virtue of such provision, the shaft part 121 of the pedal rod assembly 
can be turned into the clevis part 41 and with the development of at five 
(5) to forty (40) inch pounds of torque resistance, the two elements of 
the pedal rod will never come apart. 
The inch pounds of resistance torque can be selectively varied by engaging 
a selected number of thread segments 170 with the threads 60-61 in the 
clevis 41. 
It will be understood that it is contemplated that the clevis could be 
formed as shown at 141 of two separate parts 142 and 143 as depicted in 
FIG. 15 or could be formed to provide a single arm or rod configuration 
instead of a clevis, in which event the work piece would end up in the 
configuration of either FIG. 15 or FIG. 16 wherein the two piece version 
or the folded one piece version are shown with apertured arms 152 and 153, 
respectively. 
Although minor modifications might be suggested by those versed in the art, 
it should be understood that I wish to embody within the scope of the 
patent warranted hereon all such modifications as reasonably and properly 
come with the scope of my contribution to the art.