Control system for an injection molding machine

A control system is applicable for an injection molding machine which has a temperature setting function and display function. The control system includes a temperature scale/unit setting function for selecting a temperature setting and a displaying mode which changes a data display between a Centigrade mode (where a temperature setting device and temperature on the display are performed in Centigrade) and a Fahrenheit mode. The control system also includes a display switching function for temporarily switching the display mode to a mode different from the current temperature setting mode as set by the temperature scale/unit setting function and a display mode restoring function for switching the temporarily switched display mode to the original display mode.

BACKGROUND OF THE INVENTION 
1. Field of the Invention 
The present invention relates to a control system for an injection molding 
machine having a temperature setting function and a temperature displaying 
function. 
2. Description of the Related Art 
In the prior art, an injection molding machine which can perform setting 
and displaying of molding conditions and so forth at different temperature 
scales/units has been known as disclosed in Japanese Examined Utility 
Model Publication (Kokoku) No. Heisei 6-9832, for example. Such type of 
injection molding machine is constructed to permit selection of one of a 
Centigrade mode (.degree.C.), in which the Centigrade temperature 
scale/unit is used for expressing temperature, and Fahrenheit mode, in 
which the Fahrenheit temperature scale/unit is used for expressing 
temperature, upon setting and displaying temperature. Having the two 
temperature scales permits adaption of the injection molding machine to 
conditions in various countries employing one of the temperature 
scales/units. For instance, Japan employs the Centigrade temperature scale 
and the United States and so forth employs the Fahrenheit temperature 
scale. 
On the other hand, in general, when the temperature scale/unit is varied, 
numerical values are often varied significantly. In case of the expression 
of the temperature, a value of the temperature is significantly different 
between Centigrade and Fahrenheit. For instance, 100.degree. in Centigrade 
corresponds to 212.degree. in Fahrenheit. Thus, the value becomes 
approximately double in case of the Fahrenheit expression in comparison 
with the Centigrade expression. 
Accordingly, if the temperature mode is switched into the Centigrade mode 
in erroneous operation or verification of temperature by other person in 
the country where the Fahrenheit mode is employed, an operator may 
misunderstand that the displayed value of the temperature is in the 
Fahrenheit mode and thus make judgement that the temperature is lowered to 
be approximately half. Then, the operator may abruptly set the value to be 
approximately half in error. In such case, overheating of the machine 
occurs and results in failure of molding and equipments. 
SUMMARY OF THE INVENTION 
The present invention is to solve the problems existing in the prior art. 
Therefore, it is an object of the present invention to provide a control 
system for an injection molding machine which can certainly prevent 
erroneous setting of the temperature associated with switching of 
temperature scales/units in a display. 
According to one aspect of the invention, a control system for an injection 
molding machine having a setting function and a display function of 
temperature, comprises: 
a temperature scale/unit setting means for selectively setting a 
temperature expression scale/unit for temperature setting and displaying 
to one of a Centigrade mode and a Fahrenheit mode; 
a display switching function portion for switching only the temperature 
scale/unit for displaying into the other of temperature expression unit; 
a display switching release function portion for releasing switching by the 
display switching function portion to restore an original temperature 
expression scale/unit as set by the temperature scale/unit setting means; 
and 
a setting inhibiting function portion for inhibiting setting of temperature 
while the temperature expression scale/unit is switched to the other 
temperature expression scale/unit by the display switching function 
portion. 
In the preferred construction, the display switching function portion is 
responsive to operation of a predetermined key to effect switching of the 
temperature expression scale/unit for displaying. Also, the display 
switching release function portion may be responsive to operation of an 
arbitrary key for releasing switching of the temperature expression 
scale/unit by the display switching function portion, or, in the 
alternative, the display switching release function portion may be 
responsive to expiration of a predetermined period after switching of the 
temperature expression scale/unit into the other temperature expression 
scale/unit for restoring an original temperature expression scale/unit as 
set by the temperature scale/unit setting means. 
A display color may be varied while the other temperature expression 
scale/unit is displayed in response to operation of the display switching 
function portion. 
With the construction set forth above, once the temperature expression 
scale/unit for setting and displaying the temperature is set by the 
temperature scale/unit setting means into either the Centigrade mode or 
the Fahrenheit mode, the temperature expression scale/unit for display may 
be temporarily switched into the other mode by the display switching 
function portion. While the temperature is displayed in the switched mode, 
setting of the temperature is inhibited by the setting inhibiting function 
portion so that erroneous setting of the temperature associated with 
temporarily switching of the temperature expression scale/unit can be 
certainly prevented. Also, the display switching release function portion 
may release switching by the display switching function portion to restore 
the original temperature expression scale/unit. 
Further scope of applicability of the present invention will become 
apparent from the detailed description given hereinafter. However, it 
should be understood that the detailed description and specific examples, 
while indicating preferred embodiments of the invention, are given by way 
of illustration only, since various changes and modifications within the 
spirit and scope of the invention will become apparent to those skilled in 
the art from this detailed description.

DESCRIPTION OF THE PREFERRED EMBODIMENT 
Next, the present invention will be discussed hereinafter in detail in 
terms of the preferred embodiment with reference to the accompanying 
drawings. In the following description, numerous specific details are set 
forth in order to provide a thorough understanding of the present 
invention. It will be obvious, however, to those skilled in the art that 
the present invention may be practiced without these specific details. In 
other instances, well-known structures are not shown in detail in order to 
unnecessary obscure the present invention. 
Firstly, a construction of the preferred embodiment of a control system 1 
for an injection molding machine according to the present invention will 
be discussed with reference to FIG. 1. 
FIG. 1 shows a major part of the control system 1. It should be noted that 
an external appearance of an entire injection molding machine M is 
illustrated in phantom line. The injection molding machine M has a base 
10. A mold 12 is mounted on a clamping device 11 which is located on the 
upper surface of the front portion of the base 10, and an injection device 
13 is mounted on the upper surface of the rear portion of the base 10 and 
movable toward and away from the mold 12. On the other hand, the base 10 
houses a control system 1 having a computer function. The control system 1 
includes a display portion 15 and a keyboard (operation panel) 16 arranged 
at a side surface of the base. Within the base 10, hardware including a 
control unit (including a CPU or so forth) 17, a ROM 18, a RAM 19 and so 
forth necessary for computer process are mounted. 
On the other hand, the reference numeral 2s denotes a temperature 
scale/unit setting switch, which is connected to the control scale/unit 17 
to form a temperature unit setting means 2. By means of the temperature 
scale/unit setting switch 2s, a unit for temperature setting and 
displaying can be set to either a Centigrade mode (.degree.C.) or a 
Fahrenheit mode (.degree.F.). Accordingly, by switching the temperature 
scale/unit setting switch 2s toward the Centigrade mode, for example, the 
temperature scale/unit of setting and displaying of the temperature can be 
unified in the Centigrade mode (.degree.C.). Here, it is preferred that 
the temperature scale/unit setting switch 2s is arranged at a position 
other than the keyboard 16 and thus being not normally accessible. 
Also, the reference numeral 3k denotes a display switching key for 
switching only the display to the other temperature scale/unit. 
Accordingly, when the temperature scale/unit setting switch 2s is in the 
Centigrade mode position, only the display of the temperature may be 
switched into the Fahrenheit mode by switching operation of the display 
switching key 3k. The display switching key 3k may be formed utilizing a 
touch panel 20 displayed on the display portion 15. With the display 
switching key 3k and the control unit 17 processing an switching 
information from the display switching key 3k, a display switching 
function portion 3 is formed. 
On the other hand, the reference numeral 4 denotes a display switching 
release function portion. The display switching release function portion 4 
has a function responsive to depression of arbitrary key 4k on the 
keyboard 16 and the touch panel 20 (see FIG. 5) to provide information 
thereof to the control unit 17, and thus to release switching of the 
temperature scale/unit by the display switching function portion 3 for 
restoring to an original temperature scale/unit. Therefore, the 
construction of such display switching release function portion 4 may be 
commonly used with a setting inhibiting function portion 5 which inhibits 
setting of the temperature while the temperature scale/unit on the display 
is switched by the display switching function portion 3 into the unit 
other than the unit set by the unit setting switch 2s. 
Next, the function (operation) of the preferred embodiment of the control 
system 1 for the injection molding machine will be discussed hereinafter 
with reference to a flowchart in FIG. 2 and FIGS. 3 to 5. 
First, by the temperature scale/unit setting switch 2s, the temperature 
scale/unit mode is selected between the Centigrade mode and the Fahrenheit 
mode (step S1). Here, for the purpose of disclosure, the following 
disclosure will be given in the case where the Centigrade mode is selected 
through the temperature scale/unit setting switch 2s at step S1. By this, 
units of the temperature setting and displaying is unified into the 
Centigrade mode (.degree.C.). Accordingly, as shown in FIG. 3, the 
temperature display in the Centigrade mode, such as "Temperature 
100.degree. C." on the display portion 15. Upon setting of the temperature 
for a molding temperature, a heating cylinder temperature and so forth, 
setting process in the Centigrade mode is performed (steps S3 and S4). 
On the other hand, if it is desired to check the temperature in the 
Fahrenheit mode, by touching the display switching key 3k of the touch 
switch 20 displayed on the display portion 15 by a finger A, as shown in 
FIG. 4, the temperature display of the display portion 15 is switched into 
the display in the Fahrenheit mode, namely such as "Temperature 
212.degree. F." (steps S2 and S5). By this, the temperature in the 
Fahrenheit mode can be seen. 
On the other hand, as shown in FIG. 5, by arbitrarily depressing any key 4k 
on the keyboard 16 and the touch panel 20, switching of display by the 
display switching function portion 3 is released for restoring display in 
the original temperature scale/unit. Therefore, even when the operator 
misunderstands the value "212" on the display, as the Centigrade mode 
expression, for example, to attempt to reset temperature, the display on 
the display portion 15 is instantly restored to the temperature display of 
"Temperature 100.degree. C.". Thus, erroneous setting of the temperature 
can be successfully avoided. On the other hand, while the temperature 
display is switched into the Fahrenheit mode by the display switching key 
3k, setting of the temperature is inhibited by the setting inhibiting 
function portion 5 established in common to the display switching release 
function portion 4 (step S7). 
Such function is similar to the case where the temperature scale/unit is 
switched into the Fahrenheit mode by the temperature scale/unit setting 
switch 2s. In the foregoing explanation, the Centigrade mode is replaced 
with the Fahrenheit mode and the Fahrenheit mode is replaced with the 
Centigrade mode. 
As set forth above, the control unit for the injection molding machine 
according to the present invention can successfully prevent erroneous 
setting of the temperature associating with switching of the temperature 
display scale. Therefore, failure of molding in overheating or harmful 
influence to the equipments can be prevented. 
Although the invention has been illustrated and described with respect to 
exemplary embodiment thereof, it should be understood by those skilled in 
the art that the foregoing and various other changes, omissions and 
additions may be made therein and thereto, without departing from the 
spirit and scope of the present invention. Therefore, the present 
invention should not be understood as limited to the specific embodiment 
set out above but to include all possible embodiments which can be 
embodies within a scope encompassed and equivalents thereof with respect 
to the feature set out in the appended claims. 
For instance, the temperature scale/unit setting means 2 is exemplified in 
the case where temperature scale/unit is set by means of the temperature 
scale/unit setting switch 2s provided in the injection molding machine. 
However, the temperature scale/unit setting means 20 may encompass the 
case where a ROM set in one of the temperature scales/units is 
preliminarily installed upon shipping. 
On the other hand, the display switching release function portion 4 may be 
constructed to return the original temperature scale/unit by releasing 
switching of the display by the display switching function portion 3 after 
expiration of a given period. In this case, the setting inhibit function 
portion 5 executes, in a software program, a process for inhibiting 
setting based on touching operation of the predetermined key 3k to release 
process for inhibiting setting after expiration of the given period. 
Furthermore, when the display is switched by the display switching 
function portion 3, it is possible to cause blinking or vary display color 
for temperature display of the switched unit. 
Furthermore, while the foregoing embodiments have been discussed in terms 
of temperature as switched between the Centigrade mode and the Fahrenheit 
mode, the present invention is applicable not only for temperature 
expression but also for various other units, such as weight, volume and so 
forth. In addition, the control of numerical setting and displaying in a 
plurality of mutually distinct units may be applicable not only for 
injection molding technology but also various other technologies requiring 
numerical setting of parameters in variable units.