Control unit and electrical switch construction therefor and methods of making such a control unit and electrical switch construction

A control unit having a condition selector, an electrical switch having an actuator unit provided with an adjustable movement differential, a condition responsive device for actuating the switch when the condition responsive device senses certain conditions selected by the selector, and a lever arrangement carried by the unit and being operatively associated with the actuator unit of the switch and the device whereby the device can actuate the switch by the lever arrangement, the lever arrangement having a first adjustable lever operatively interconnected to the selector and acting as a main range lever. The first lever is operatively interconnected to the condition responsive device and to the actuator unit of the switch. The lever arrangement has a second adjustable lever operatively interconnected to the selector and to the actuator unit of the switch for adjusting the movement differential of the actuator unit of the switch.

This invention relates to an improved condition responsive control unit and 
to an electrical switch construction thereof as well as to methods of 
making such a control unit and such an electrical switch construction. 
It is well known to provide a control unit having a condition selector 
means, an electrical switch, a condition responsive device for actuating 
the switch when the condition responsive device senses certain conditions 
selected by the selector means and lever means carried by the unit and 
being operatively associated with the switch and the device whereby the 
device can actuate the switch by the lever means, the control unit having 
means for adjusting the differential in the operation of the switch for 
such a unit or the like. For example, see the U.S. patent to cumming, U.S. 
Pat. No. 3,952,611 which is assigned to the same assignee to whom this 
application is assigned. 
It is a feature of this invention to provide improved means for adjusting 
the differential in the operation of the switch of such a control unit. 
In particular, in the control unit of the aforementioned U.S. Pat. No. 
3,952,611, the cut-out temperature was selected by the selector means nd 
then the temperature differential (either positive or negative) was set by 
the selector means. However, in the control unit of this invention, both 
the cut-out temperature and the cut-in temperature can be set 
independently of each other. 
For example, one embodiment of this invention provides a control unit 
having a condition selector means, an electrical switch having an actuator 
means provided with an adjustable movement differential, a condition 
responsive device for actuating the switch when the condition responsive 
device senses certain conditions selected by the selector means, and lever 
means carried by the unit and being operatively associated with the 
actuator means of the switch and the device whereby the device can actuate 
the switch by the lever means, the lever means having a first adjustable 
lever operatively interconnected to the selector means and acting as a 
main range lever. The first lever is operatively interconnected to the 
condition responsive deivce and to the actuator means of the switch. The 
lever mens has a second adjustable lever operatively interconnected to the 
selector means and to the actuator means of the switch for adjusting the 
movement differential to the actuator means of the switch. 
The electrical switch construction of this invention for such a unit has an 
actuator means provided with adjustable means for adjusting the movement 
differential ofthe actuator means without adjusting the air gap between 
the contact stops for the switch blade of the switch, the selector means 
being operatively associated with the adjustable means through the lever 
means to selectively adjust the movement differential of the switch. 
Accordingly, it is an object of this invention to provide an improved 
control unit having one or more of the novel features of this invention as 
set forth above or hereinafter shown or described. 
Another object of this invention is to provide a method of making such a 
control unit, the method of this invention having one or more of the novel 
features of this invention as set forth above or hereinafter shown or 
described. 
Another object of this invention is to provide an improved electrical 
switch constrution, the electrical switch construction of this invention 
having one or more of the novel features of this invention as set forth 
above or hereinafter shown or described. 
Another object of this invention is to provide an improved method of making 
such an electrical switch construction, the method of this invention 
having one or more of the novel features of this invention as set forth 
above or hereinafter shown or described.

While the various features of this invention are hereinafter described and 
illustrated as being particularly adapted to provide for a control unit 
that is temperature responsive, it is to be understood that the various 
features of this invention can be utilized singly or in any combination 
thereof to provide a control that is responsive to other conditions as 
desired. 
Therefore, this invention is not to be limited to only the embodiments 
illustrated in the drawings, because the drawings are merely utilized to 
illustrate one of the wide variety of uses of this invention. 
Referring now to FIGS. 1, 2 and 3, the improved control unit of this 
invention is generally indicated by the reference numeral 20 and comprises 
a housing means 21 having a condition selector means that is generally 
indicated by the reference numeral 22, an electrical switch construction 
that is generally indicated by the reference numeral 23, a condition 
responsive device that is generally indicated by the reference numeral 24 
for actuating the switch construction 23 when the condition responsive 
device 24 senses certain conditions selected by the selector means 22, and 
lever means generally indicated by the reference numeral 25 and being 
carried by the housing means 21 in a manner to be operatively associated 
with the electrical switch construction 23 and the condition responsive 
device 24 whereby the condition responsive device 24 can actuate the 
switch construction 23 by the lever means 25, the lever means 25 including 
a first adjustable lever 26 operatively interconnected to the selector 
means 22 and acting as a main range lever for the switch construction 23 
in a manner hereinafter described; and a second adjustable lever 27 
operatively interconnected to the selector means 22 for adjusting the 
movement differential of the switch construction 23 in a manner 
hereinafter set forth. 
As best illustrated in FIG. 9, the electrical switch construction 23 of 
this invention is generally of the type set forth in the aforementioned 
co-pending parent patent application and comprises a housing means 28 
formed from a first housing part 29 cooperating with a cover housing part 
30 to define a chamber 31 therein containing a snap switch blade 32 
adapted to be operated by a actuator means that is generally indicated by 
the reference numeral 33 to switch a contact carrying portion 34 of the 
switch blade 32 between a pair of spaced contact stops 35 and 36 
respectively electrically interconnected to terminal means 37 and 38, the 
switch blade 32 being mounted to the housing means in a cantilever manner 
by its terminal means 39 that is also external to the housing means 28. 
In this manner, the terminal 39 is adapted to be electrically 
interconnected to the terminal 38 of the switch construction 28 when the 
switch blade portion 34 has its upper contact 40 disposed in electrical 
contact with the contact 36 as illustrated in FIG. 9. However, when the 
actuator means 33 is moved inwardly in a manner hereinafter described, the 
switch blade 32 is snapped from the upper contact 36 of the lower contact 
35 whereby a lower contact 41 on the contact carrying portion 34 of the 
blade 32 is placed in electrical contact with the electrical contact 35 so 
that the terminal 39 is now electrically interconnected to the terminal 
37. 
The actuator means 33 of this invention includes an actuator button or 
plunger 42 that has a part 43 projecting out of an opening 44 in the cover 
30 and being urged to its out position by a return compression spring 45 
having one end 46 bearing against the housing part 29 and the other end 47 
bearing against an enlarged end 48 of the plunger 42. 
The actuator means 33 also includes an actuator spring 49 that has one leg 
50 pivoted to a part 51 of a rear portion 52 of the blade 32 and another 
leg 53 interconnected to a tongue part 54 of the forward portion 34 of the 
blade 32, the legs 50 and 53 of the actuator spring 49 being compressed 
toward each other when assembled with the blade 32 into the arrangement 
illustrated in FIG. 9. An intermediate central part 55 of the actuator 
spring 49 has an opening 56 passing therethrough and receiving the reduced 
portion of the plunger 42 therethrough whereby a pair of intermediate 
tongues or parts 57 of the actuator spring 49 are disposed in a lost 
motion means or air gap 58 of the actuator means 33 that is defined 
between a shoulder 59 on the end 48 of the plunger 42 and a shoulder 60 on 
a sleeve 61 telescoped about the plunger 42 and having an end 62 also 
projecting out of the opening 44 of the cover 30 of the housing 29 as 
illustrated in FIG. 9 for a purpose hereinafter described. Thus, the 
actuator spring 49 can move relative to the actuator means 33 as will be 
apparent hereinafter. 
As illustrated schematically in FIG. 11, the pivot point of the actuator 
spring 49 is indicated by the reference numeral 63 while the pivot point 
for the switch blade 32 is indicated by the reference number 64 wherein it 
can be seen that the pivot points 63 and 64 for the actuator spring 49 and 
switch blade 32 are disposed in a straight line that bisects the air gap 
between the normally closed contact stop 36 and the normally open contact 
stop 35 with the pivot points 63 and 64 being separated from each other 
for a purpose hereinafter described. The tongue 54 of the switch blade 32 
is interconnected to the leg 53 of the actuator spring 49 at the reference 
numeral 65 in FIG. 11. 
When the actuator spring 49 is being moved upwardly about its pivot point 
63 in FIG. 11 by the shoulder 60 of the sleeve 61 of the actuator means 33 
pushing upwardly on the intermediate parts 57 of the actuator spring 49 in 
opposition to the force of the reset or return spring 45, the point 65 of 
interconnection of the switch blade tongue 54 and the actuator spring 49 
moves upwardly and when the same reaches the point represented by the 
reference numeral 66, the actuator spring 49 itself snaps over center to 
cause stored energy in the spring 49 to move the actuator spring 49 
rapidly upwardly relative to the actuator sleeve 61 and plunger 42 through 
the air gap or lost motion means 58 thereof and when the point 65 of the 
actuator spring 49 reaches the point represented by the reference numeral 
67 in FIG. 11, the over center position for the switch blade 32 is now 
reached whereby the switch blade 32 snaps over center. When the blade 32 
snaps over center through the force of the spring 49, the contact portion 
34 thereof snaps rapidly downwardly to place the lower contact 41 thereof 
against the normally open contact 35 as represented by dash-dotted lines 
in FIG. 11. Thus, it can be seen that when the actuator spring 49 has the 
point 65 thereof reach the point 66 so that the stored energy of the 
actuator spring 49 takes over, the actuator spring 49 still must move the 
distance between the points 66 and 67 before the switch blade 32 moves 
over center so that the time when the point 65 on the actuator spring 49 
reaches the over center point 66 of the actuator spring 49, the switch 
blade 32 is maintaining the upper contact 40 thereof in contact with the 
fixed upper contact 36 with a sustained contact force at this so-called 
"trip point" of the switch construction 23 for the reasons fully advanced 
in the aforementioned copending patent application. 
When the actuator means 33 moves outwardly from the tripped position 
previously described in a manner hereinafter described, so that the force 
of the return or reset compression spring 45 can move the plunger 42 
downwardly, the shoulder 59 on the end 48 of the plunger 42 comes into 
contact with the intermediate parts 57 of the actuator spring 49 and moves 
the point 65 of the actuator spring 49 downwardly until the same reaches 
the point 68 in FIG. 11 whereby the actuator spring 49 now goes over 
center in the opposite direction and snaps downwardly relative to the 
actuator plunger 42 through the lost motion means 58 to carry the point 65 
to the point 69 whereby the switch blade 32 is now moved over center so 
that the blade 32 is snapped from the down position back to the up 
position illustrated in FIG. 9. Thus, it can be seen that a contact force 
is being sustained at the lower contact 35 at the time that the actuator 
spring 49 moves over center at the point 68 which is the "trip point" of 
the switch construction for the reasons and purposes fully advanced in the 
aforementioned co-pending patent application. 
In this manner, it can be seen that the distance of the air gap 58 between 
the shoulders 59 and 60 of the actuator means 33 determines the movement 
of the actuator means 33 for causing the switch blade 32 to move between 
the spaced contact stops 36 and 35. 
Therefore, by making the sleeve 61 of the actuator means 33 adjustable 
relative to the plunger 42 in a manner hereinafter described, the air gap 
or lost motion means 58 can be adjusted to have the shoulder 60 moved 
relative to the shoulder 59 a desired distance so that the movement 
differential of the switch construction 10 of the actuator means 33 can be 
adjusted without causing any change in the contact forces being sustained 
at the contacts 35 and 36 for the reasons fully advanced in the 
aforementioned co-pending parent patent application. 
The plunger 42 of the actuator means 33 of the switch construction 23 is 
controlled by the position of the main lever 26 of the lever arrangement 
25 of the control unit 22. In particular, an intermediate part 70 of the 
lever 26 bears against an end surface 71 of an externally threaded member 
72 forming part of the selector means 22 and being threaded in a fixed 
threaded member 73 carried by the housing means 21 whereby rotation of the 
threaded member 72 relative to the fixed threaded member 73 will move the 
end 71, and, thus, the pivot point for the lever 26 relative to the switch 
construction 23 as illustrated schematically in FIG. 12. 
The main lever 26 has one end 74 thereof carrying an adjusting member 75 
for bearing against the projecting portion 43 of the plunger 42 as 
illustrated in FIG. 2 while the other end 76, FIG. 4, of the lever 26 is 
adapted to bear against an end member 77 that forms part of a movable wall 
of a bellows construction 78 that defines part of the condition responsive 
device 24 as illustrated. As illustrated in FIGS. 2 and 6, a leaf like 
spring member 79 is fixed to the housing means 21 by a rivet 80 so that a 
free end 81 of the leaf spring member 79 bears against the intermediate 
part 70 of the lever 26 to always maintain the intermediate part 70 in 
engagement with the end 71 of the adjusting member 72 as illustrated. 
A compression spring 82 has one end 83 bearing against the housing means 21 
and the other end 84 thereof bearing against the end member 77 of the 
bellows construction 78. 
In this manner, the expansion of the bellows construction 78 to the right 
in FIG. 2 upon sensing an increase in temperature will cause the lever 26 
to pivot in a counter clockwise direction about the pivot point 71 for the 
lever 26 as illustrated in FIG. 2 and schematically in FIG. 12 to thereby 
cause the end 74 of the lever 26 to operate the actuator means 33 of the 
switch construction 23 in a direction into the switch construction 23 for 
a purpose herein after described. Conversely, a decrease in sensed 
temperature causes the bellows construction 78 to collapse under the force 
of the compression spring 82 and thereby permits the lever 26 to be 
pivoted about the pivot point 71 in a clockwise direction by the switch 
return spring 45 so that the end 74 of the lever 26 moves outwardly with 
the actuator means 33 relative to the switch construction 23. Thus, the 
return spring 45 moves the actuator means 33 of the switch construction 23 
downwardly in FIG. 9 and FIG. 12 for a purpose hereinafter described. 
Thus, by rotating the threaded member 72 by an interconnected knob 
construction 85 of the selector means 22 relative to a fixed indicator 
means 86, the pivot point 71 for the lever 26 is adjusted as will be 
apparent hereinafter and will set the cut out temperature for the control 
unit 20, i.e., will set the temperature which will cause the control unit 
20 to move the switch blade 32 away from the lower contact 35 and return 
the switch blade 32 against the upper contact 36 as illustrated in FIG. 9 
whereby in one example of the unit 20 a heat exchanger will have its 
cooling output effect turned off as the heat exchanger only has its 
cooling operation turned on in this example when the switch blade 32 is 
against the lower contact 35. 
Conversely, by adjusting the pivot point of the lever 27 in a manner 
hereinafter described by the selector means 22 in a manner hereinafter 
described, such adjustment will select the cut in temperature for the unit 
22 for causing the switch blade 32 to have its contact portion 34 snapped 
away from the contact 36 and placed into contact with the lower contact 35 
in FIG. 9 so that the heat exchanger will have its cooling output effect 
turned on by the switch construction 23 until the output temperature 
effect reaches the cut out temperature setting of the adjusting member 72. 
For example, the control knob 85 of the selector means 22 can carry a 
temperature plate 87 which will be exposed at a cut out 88 in a cover 
member 89 of the control unit 20 as illustrated in FIG. 1 whereby rotation 
of the knob 85 will move the dial face 87 relative to a fixed indicator 
pointer 90 on the cover member 89 to indicate the temperature setting for 
the control unit 20 to turn off the cooling output temperature effect of 
the heat exchanger when the output temperature effect thereof reaches a 
temperature set by the dial face 87 relative to the stationary pointer 90 
as will be apparent hereinafter. 
The lever 26 carries a threaded adjusting member 91 at the pivot portion 70 
thereof with the threaded member 91 having an enlarged end 92 against 
which a bifurcated end 93 of the second lever 27 is pivoted against by a 
compression spring 94 having one end 95 bearing against a portion 96 of a 
lever 26 and the other end 97 thereof bearing against the end 98 of the 
lever 27 which has an intermediate portion 99 thereof being pivoted on a 
portion 100 of the lever 26 as illustrated in FIGS. 1 and 4 and 
schematically represented by the pivot point 101 in FIGS. 13 and 14. 
Thus, the position of adjustment of the end 92 of the adjustable member 91 
relative to the intermediate part 70 of the first lever 26 determines the 
distance that the end 98 of the lever 27 will be set from the end 74 of 
the lever 26 as illustrated in FIGS. 13 and 14. The end 98 of the lever 27 
bears against the shoulder 62 of the sleeve 61 which is normally held into 
contact with the end 98 of the lever 27 by the force of the actuator 
spring 49 when the actuator spring 49 is in the position illustrated in 
FIG. 9. 
A rotatable adjusting member 102 is carried on a plate-like portion 103 of 
the adjusting knob 85 and can be rotated relative thereto and through a 
spring drive 104 provide rotational movement of the threaded member 91 
relative to the intermediate part 70 of the lever 26 whereby rotation of 
the member 102 will set the adjustment of the adjusting member 91 relative 
to the lever 26 and, thus, the adjustment of the end 98 of the lever 27 
relative to the end 74 of the lever 26. 
As illustrated in FIG. 3, the dial plate means 87 has an inner scale 105 
thereon against which a pointer part 106 of the rotatable member 102 can 
be positioned to set the cut in temperature of the control unit 20, such 
movement of the member 102 relative to the dial plate means 87 of the 
control knob 85 is independent of the adjusting member 72 of the control 
knob or selector means 22 and the adjustment of the control knob 85 for 
the adjusting member 72 is independent of the position of the member 102. 
Thus, when the control knob 85 is rotated to set the cut out temperature, 
and, thus, the pivot point 71 for the first lever 26 of the lever 
arrangement 25, the member 102 does not move and likewise when the member 
102 is rotated to set the position of the end 93 of the lever 27 relative 
to the intermediate part 70 of the lever 26, the member 72 does not move. 
It can be seen in FIG. 14 that the gap A between the surfaces 59 and 60 of 
the plunger 42 and sleeve 61 controls the movement of the switch 
construction 23 actuator spring 49. As this gap A is varied, the movement 
differential of the switch construction 23 is varied and likewise the 
temperature differential of the control unit 20 changes. Gap A is directly 
related to gap B in FIG. 14 through the adjustment sleeve 61. Gap B is 
altered through the turning of the differential adjusting screw 91 which 
changes the gap C in FIG. 14 which is the distance between the end 93 of 
the lever 27 and the intermediate part 70 of the lever 26. The 
differential adjusting screw 91 is grounded to the pivot 70 of the main 
lever 26 so that a coaxial range-differential adjustment is possible. 
In one embodiment of the control unit 20, the power element 78, switch 
lever ratio is 1:3.625 and this gives a minimum temperature differential 
of 1.85.degree. F. with a switch movement differential of 0.004 of an 
inch. If gap C is opened approximately 0.015 of an inch, opening gap B and 
gap A approximately 0.072 of an inch, the switch movement differential 
becomes approximately 0.076 of an inch and the control temperature 
differential is approximately 35.degree. F. Accordingly, there is no lost 
motion or gap variation during the control's functioning as with the 
control unit of the aforementioned U.S. Pat. No. 3,952,611 as the gap 
changes in the control unit 20 of this invention only occurs during 
differential changes. 
Accordingly, it can be seen that the control unit 20 of this invention can 
be formed with a unique lever arrangement 25 to permit independent 
adjustments of the cut in and cut out temperatures thereof whereby the 
control unit 20 will operate in a manner now to be described. 
When the operator desires to set the control unit 20 for turning on a 
cooling heat exchange unit when the temperature reaches 80 degrees and for 
turning off the heat exchange unit when the temperature reaches 70.degree. 
F., the operator can set the selector means 22 for when the control unit 
20 is to turn off the output cooling effect of the heat exchanger by 
rotating the control knob 85 relative to the fixed pointer 90 in FIG. 1 to 
position the desired temperature on the outer scale of the plate 87 
relative to the pointer 90 so that the unit 20 will turn off the heat 
exchanger when the temperature is lowered to 70.degree. F. Such rotation 
of the knob 85 rotates the adjusting member 72 and, thus, positions the 
pivot point 71 for the lever 26. The operator then removes the cover of 
the control knob to reach the adjusting member 102. The operator adjusts 
the member 102 relative to the inner scale 105 until the pointer 106 is 
set for 80 degrees whereby such adjustment of the member 102 adjusts the 
threaded member 91 relative to the intermediate part 70 of the lever 26 so 
that the gap A between the shoulders 60 and 59 of the sleeve 61 and 
plunger 42 of the actuator means 33 of the switch construction 23 is 
adjusted. 
With the members 102 and 85 of the selector means 22 so adjusted and as the 
temperature being sensed by the power element 78 increases to the cut in 
temperature of 80.degree. F., the same moves the movable wall 77 to the 
right in FIG. 2 and thereby causes the two levers 26 and 27 to pivot in 
unison in a counter clockwise direction about the pivot point 71 for the 
lever 26 so that the shoulder 60 on the sleeve 61 moves the actuator 
spring 49 upwardly in FIG. 9 to such a position that the same snaps over 
center as illustrated in FIG. 11 to cause the switch blade 32 to 
subsequently snap over center and move the contact portion 34 thereof 
downwardly away from the upper contact 36 and into contact with the lower 
contact 35 to thereby turn on the heat exchange unit which now begins to 
cool the building, etc. where the control unit 20 is located. 
With the heat exchange unit now turned on, the temperature being sensed by 
the device 24 now decreases and when the same has decreased to 70.degree. 
F. to cause the bellows 78 to collapse through the spring 82 and thereby 
permit the levers 26 and 27 to pivot in unison in a clockwise direction 
about the pivot point 71 a distance sufficient so that the return spring 
45 has moved the shoulder 59 of the plunger 42 downwardly in FIG. 9 a 
sufficient distance to cause the actuator spring 49 to snap over center as 
represented in FIG. 11 and cause the switch blade 32 to snap over center 
back to the position illustrated in FIG. 9, the heat exchange unit is 
turned off to terminate the output cooling effect. 
Thus, it can be seen that the control unit 20 will cycle the heat exchange 
unit on and off at the two temperatures selected by the selector means 22 
to tend to maintain the temperature effect between the cut in and cut out 
temperatures selected thereby. 
Accordingly, it can be seen that the control unit 20 of this invention 
provides separate and independent adjustments for the cut in and cut out 
temperature settings thereof and such adjustments are permitted by 
changing the movement differential of the switch construction 23 as 
previously described. 
For example, adjustment of the lever 26 by the member 72 sets the 
temperature for when the shoulder 59 of the plunger 42 will cause the 
actuator spring 49 to move the switch blade 32 from the lower contact 35 
to against the upper contact 36. Adjustment of the lever 27 by the member 
91 sets the temperature for when the shoulder 60 of the sleeve 61 will 
cause the actuator spring 49 to move the switch blade 32 from the upper 
contact 36 to against the lower contact 35 whereby the switch construction 
23 can control any desired device, whether the same be a cooling heat 
exchange unit, a heating heat exchange unit, etc. 
Accordingly, it can be seen that this invention not only provides an 
improved control unit and method of making the same, but also this 
invention provides an improved electrical switch construction and method 
of making the same. 
While the forms and methods of this invention, now preferred, have been 
illustrated and described as required by the Patent Statute, it is to be 
understood that other forms and method steps can be utilized and still 
fall within the scope of the appended claims.