Control apparatus for automotive air conditioner

On an automotive vehicle having a stick-shift transmission and an air conditioner, the air conditioner is turned off by a switch operated by the gear shift lever when shifting from neutral into first gear. The air conditioner is kept off during the relatively brief interval while the transmission is being shifted through the lower gears. The air conditioner comes on after the transmission has been shifted into high gear.

SUMMARY OF THE INVENTION 
This invention relates to an apparatus for turning off the air conditioner 
in an automotive vehicle with a stick shift transmission while the 
transmission is being shifted through the low gears. 
Various arrangements have been proposed heretofore which operate off the 
vehicle engine intake manifold to turn off the air conditioner while the 
vehicle is accelerating. U.S. Pat. No. 3,918,543 to Halem discloses such 
an arrangement. 
The present invention is directed to a novel apparatus in which the air 
conditioner is on when the transmission is in neutral, such as when the 
vehicle is paused at a stop light, and when the transmission is in high 
gear. The air conditioner is turned off while the transmission is being 
shifted from neutral through the lower gears and into high gear, thereby 
reducing the load on the engine while the vehicle is accelerating. A 
substantial amount of fuel is saved. The present invention avoids undue 
frequent acceleration of the air conditioner compressor since the 
compressor will be on only while the engine is idling in neutral or the 
engine has settled down into a relatively low RPM in high gear. The 
interior cooling of the vehicle is not seriously affected by turning off 
the air conditioner during the usually brief interval required to shift 
through the lower gears. Several embodiments of the invention are 
disclosed which are adapted for relatively simple attachment to a vehicle 
having a gear shift lever-operated transmission, whether three speed, four 
speed or five speed, and having any shifting pattern. 
A principal object of this invention is to provide a novel and improved 
apparatus for turning off the air conditioner in an automotive vehicle 
while the vehicle transmission is being shifted manually through the lower 
gears. 
Another object of this invention is to provide such an apparatus in which 
the air conditioner is turned off in response to the shifting of the gear 
shift lever out of neutral into first gear and is kept off until the 
transmission is in high gear. 
Further objects of this invention will be apparent from the following 
detailed description of three presently preferred embodiments thereof, 
which are shown in the accompanying drawings.

DETAILED DESCRIPTION 
Before explaining the disclosed embodiments of the present invention in 
detail, it is to be understood that the invention is not limited in its 
application to the details of the particular arrangements shown, since the 
invention is capable of other embodiments. Also, the terminology used 
herein is for the purpose of description and not of limitation. 
FIGS. 1-6 illustrate a first embodiment of the invention in which the 
operation of the air conditioner on a car or other automotive vehicle is 
controlled by the position of the usual gear shift lever for the vehicle's 
transmission. The vehicle also has a clutch operated by a conventional 
clutch pedal which is depressed each time the transmission is shifted. As 
shown in FIG. 6, the operating coil 25 of an electromagnetic clutch 26 for 
the compressor of the air conditioner is connected across the vehicle 
battery B through an on/off or thermostatic switch 23, a switch 20a 
operated by the gear shift lever, and a timer 24 of known design. 
The timer 24 includes a relay (not shown) having normally-closed contacts 
which open in response to the opening of switch 20a and remain open for a 
predetermined time interval, which may be set by a rotatably adjustably 
control knob. Typically, the control knob is set to establish a time delay 
of about six seconds between the opening of the gear shift lever operated 
switch 20a and the closing of the relay contacts in the timer. 
The switch 20a is a normally-open snap-acting switch of known design having 
a cantilever mounted actuator 21a (FIGS. 4 and 5) which when pushed toward 
the switch closes its normally-open contacts. Switch 20a is supported by a 
rigid channel-shaped bracket 35 (FIG. 3) at one side of the usual gear 
shift lever 31 in the vehicle. The switch actuator 21a is positioned for 
engagement by a ring 30 affixed to the gear shift lever 31 by means of a 
set screw 32 (FIG. 1). This ring may be slid down onto the gear shift 
lever 31 after first removing the latter's handle H at the top. The ring 
30 has a generally D-shaped periphery which is cylindrical on one side of 
the gear shift lever, as shown at 33, and flat on the opposite side, as 
shown at 34. 
In the neutral position of the gear shift lever (shown in full lines in 
FIG. 4), the flat surface 34 on the ring 30 engages the switch actuator 
21a and holds switch 20a closed. However, when the gear shift lever 31 is 
pivoted to the first gear position (shown in full lines in FIG. 5 and in 
phantom in FIG. 2), the ring 30 moves out of engagement with the switch 
actuator 21a, permitting switch 20a to assume its normal open condition. 
The switch remains open when the gear shift lever is in the second gear 
position (shown in phantom in FIGS. 2 and 5). When the gear shift lever 30 
is in the third gear position (shown in phantom in FIG. 4), the flat 
surface 34 on the cam 30 again engages the switch actuator 21a to open the 
switch 20a. 
With this arrangement, when the driver shifts the gear shift lever 31 out 
of neutral and into first gear, this opens switch 20a to de-energize the 
coil 25 of the clutch 26 for the air conditioner compressor. Therefore, 
the air conditioner is turned off within a fraction of a second after the 
gear shift lever is shifted into first gear. The timer 24 is turned on 
when switch 20a opens upon the displacement of the gear shift lever 31 
from neutral into first gear. When the timer turns on, it opens a set of 
relay contacts which will remain open for a predetermined time interval, 
e.g., six seconds. Therefore, even when switch 20a is closed momentarily 
by ring 30 on the gear shift lever 31 as it moves through the neutral gate 
between the first and second gear positions, or between second and third, 
the air conditioner compressor will not come on, until two conditions are 
satisfied: 
(1) the gear shift lever 31 is in third or a higher gear; and 
(2) the timer's interval (e.g., six seconds) has elapsed since the gear 
shift lever was first moved out of neutral. 
For a typical driver this six second interval will be long enough for him 
or her to complete the shifting of the gears from neutral through first 
and second gears and into third gear. Such a driver will have shifted into 
third gear to close the switch 20a by the time the relay contacts in the 
timer 24 close at the end of the six second interval to complete the 
energization circuit for coil 25, so that the compressor in the air 
conditioner can come back on. 
FIGS. 7 and 8 show a second embodiment of the invention in which the gear 
shift lever-operated switch 20a of FIGS. 1-6 and a clutch pedal-operated 
switch 20 are connected in series with the operating coil 25 of the air 
conditioner compressor's clutch 26 across the vehicle battery B, along 
with the on/off or thermostatic switch 23 for the air conditioner. 
Switch 20 is a normally-open snap-acting switch with a reciprocable 
actuator 21 which, when pushed in, closes the switch. The switch actuator 
is pushed in by the foot pedal 22 for the clutch of the vehicle in the 
normal position of the latter. When the clutch pedal 22 is depressed by 
the driver (pivoting counterclockwise in FIG. 7) to engage the clutch, it 
releases the switch actuator 21, permitting the switch 20 to assume its 
normal open condition. 
As already described in detail with reference to FIGS. 1-6, the gear shift 
lever-operated switch 20a is open when the gear shift lever 31 is in first 
or second gear position, so that under these conditions the air 
conditioner is off. When shifting gears, each time the clutch pedal 22 is 
depressed it opens the switch 20 to insure that the compressor will not 
come on during the momentary passage of the gear shift lever through the 
neutral gate as it is moved from first to second gear or from second to 
third gear. Therefore, once the gear shift lever 31 is out of neutral and 
has not yet reached the third gear position, the air conditioner will be 
kept off. 
In the embodiment of FIGS. 9 and 10, a switch 20b with normally-closed 
contacts and operated by a cantilevered actuator 21b is connected in 
series with the on/off or thermostatic switch 23 and the operating coil 25 
of the clutch 26 of the air conditioner's compressor across the battery in 
the manner shown in FIG. 6, except that the timer now is omitted from the 
circuit. This switch 20b is held open by the actuator 21b and keeps the 
air conditioner off until the manual transmission is shifted into the 
normal driving gear, such as third, fourth or fifth gear, depending upon 
the type of car. 
Inside the transmission casing 40 a longitudinally displaceable shift rail 
41 carries the shifting fork 42 whose upper end is pivotally coupled to 
the lower end of the gear shift lever 31. The lower end of this fork is 
engageable in an undercut groove 43 on an integral axial extension of the 
gear 44. When the gear shift lever 31 is shifted into this gear (after 
having been shifted through the lower gears), the shift rail 41 is 
displaced axially to the right in FIG. 9, along with the gear 44 which is 
shifted to the right along the splined shaft 45. 
As shown in FIG. 10, the switch actuator 21b is engaged by the outer end of 
a plunger 46, which is slidably received in a bushing 47 screw-threadedly 
mounted in the adjacent wall of the transmission casing. An annular head 
48 is fastened to the inner end of the plunger 46 and engages the left end 
of the shift rail 41 in FIGS. 9 and 10. A coil spring 49 is engaged under 
compression between the bushing 47 and the head 48 to bias plunger 46 and 
shift rail 41 to the right in FIG. 10. This is the position of the parts 
until the gear 44 is shifted into driving engagement in the transmission, 
and in this position the switch 20b is held open by the actuator 21b. 
With this arrangement, therefore, switch 20b remains open until gear 44 is 
shifted, at which time the displacement of the shift rail 41 to the right 
enables spring 48 to move plunger 46 to the right, releasing the switch 
actuator 21b so that switch 20b closes to energize the coil of the 
compressor clutch in the air conditioner.