The present invention relates to an Improved Timer Device herein after called "MINSAT" used for actuating an electronic device at the end of a specified time period, which could be pre set. The energy required for actuating the "MINSAT" is obtained from a high torque coil spring built in it self. They do not require any electrical energy, and can be stored for long time. The state of the art design entails the timer device for varied application wherein reliability and accuracy are the main criteria in the selection of the timer, such as in Safety & Arming Mechanism of EED (Electro Explosive Devices) and Ammunitions. Its application includes automatic control of electro- mechanical switches as well.
This MINSAT under our invention increases the confidence as well as the efficiency and safety of those who use this device for their equipment.
The present available Timer Devices used in many of the equipments especially for EED / ammunitions are not consistent in operation and its reliability is not up to the mark as far as safety and operational features are concerned during assembly, testing, handling, transportation and storage at all environmental conditions. Since these timers are often used in very critical equipments under varying climatic conditions, the reliability and accuracy are of paramount importance.
Hence a need was felt to improve the Timer device presently known. This invention precisely overcomes all the deficiencies in the existing timers. Here, we employ an innovative design using the state-of-the-art technology to improve its reliability and accuracy. '
In most of the timer devices used in EED (Electro Explosive Devices) at present rate of oscillations for the balance wheel is only about 3 oscillations per seconds where as we have designed the gear train mechanism to attain high rate of oscillations more than 3 oscillations per second.
Further we have taken care in selection of the material of construction used in MINSAT to avoid the magnetic field influence, and of due point temperature

effect on the lubricating oil and thermal effect. By making use of the nonmagnetic metallic parts having high sulfur content, we could achieve self-lubricating property. Similarly to overcome the thermal effect on the operation of the device with respect to time, accuracy and reliability, we have increased the addendums on the driven pinions to maintain minimum required mesh with mating gears. Hence the center distances of mating gears and pinions are adjusted which are at variance from the standard practice. Another design feature of MINSAT under an invention is the provision of maximum possible transverse play for gear and pinion assembly to avoid jamming.
In a preferred embodiment in our invention we have provided safety lever to indicate the operational status of the timer device. Two independent actions to operate the on-off switch is yet another feature of MINSAT. Means are also provided to automatically stop the operation of the "MINSAT", on completion of one cycle of operation. Adequate care is taken during the design, so that the "MINSAT" can operate at extreme temperature ranging from - 55° C to + 70°C. But the most optimum temperature range in which the "MINSAT" can be operate is from -55° C to + 70° C and the shelf life could be more than 15 years.
Accordingly, the present invention is an Improved Timer Device comprising Top cam (9) and Bottom cam (17) interconnected by means of Center arm (10); the Main spring (16); Center wheel (15); Gear train (8) having a plurality of gears & pinions and escapement mechanism, wherein the Center arm (5) with means for operating the timer to set in motion, is capable of rotating to wind the Main spring (16) which serves as the power source with' the provision of On-off knob (1) connected to On-off lever(13) capable of releasing that Balance wheel (14) kept under torque to oscillate the escapement mechanism of the Gear train (8), where in the Bottom cam(17) having dwell and rise portion operating a plurality micro switches mounted on a Base plate (2) adaptable to the respective equipment.

Now the invention will be described in more detail with reference to the accompanying drawings, bringing out a number of embodiments of the arrangement according to the invention.
Figure 1: Isometric view of Timer Device
Wherein
1. On-offknob
2. Base plate
3. Micro switch-1
4. Micro switch-2
5. Safety Lever
6. Body
7. Safety cover
Figure 2: Sectional view 01 of Timer Device
Wherein
8. Gear train
9. Top cam
10. Center arm
11. Gear train top plate
12. Gear train bottom plate
Figure 3: Sectional view 02 of Timer device
Wherein 13.0n-off lever
14. Balance wheel
15. Center wheel
16. Main spring
17. Bottom cam
Figure 4: Circuit of Micro switches
Wherein
18. Battery-1
19.Battery-2
20. Firing Capacitor
21. Electric Igniter
22. Digital Electronic circuit
23. Analog Electronic circuit
The Purpose of the On-off knob (1) is to switch on to initiate the sequential operation of the timer device. This On-off Knob (1) is not only serve the purpose

of initiating the action of the timer device but also designed in such a way that unless two means of action (viz., pressing the knob downward direction and rotating clockwise direction simultaneously) is applied, the initiation of the timer does not take place. In one of the preferred embodiment under this invention to start the timer we have to apply a force of 3kg in down wards direction and rotate 27° in clockwise direction with self-arresting mechanism. The minimum torque to be applied for this rotation is 25 N-mm.
This in turn releases the balance wheel (14) which had been locked by the On-off lever mechanism (13). The Balance wheel (14) is under a torque of, say 5Kg-cm maintained by the Main spring (16) through a plurality of interconnected gear wheels and pinions as shown in the figure 2 as gear train (8) mechanism. The Main spring (16) is fixed to the Center arm (10) by suitable means such as by riveting.
By rotating the Center arm (10) in clockwise direction using a key, the Main spring (16) can be wound. Whenever the timer is to be reset to its original position, one can rotate the Center arm (10) to clock wise direction and wound the Main spring (16).
Top cam (9) and Bottom cam (17) are connected through the Center arm (10), which in turn has Center wheel (15) connected to a Gear train mechanism (8) having a plurality of gears and pinions. Balance wheel (14) in turn is connected to escapement mechanism, which is a part of the Gear train (8) mechanism.
The Bottom cam (12) is assembled in such a way that the rise portion presses the plunger of the Micro switch 'V (3) as well as Micro switch '2' (4) so that micro switch terminal '1' and '4' are in normally opened condition and '2' and '3' are in normally closed condition (Refer Fig. 4).
After the lapse of the first preset timing say 30 minutes the dwell position of the rotating Bottom cam (17) reaches the plunger of the Micro switch '1' (3) and

releases the same so that terminal '1' and '4' gets closed and terminal '2' and '3' gets opened.
Similarly after the laps of required preset timing of say 50 minutes, once again the dwell position of the rotating Bottom cam (17) releases the plunger of the Micro switch '2' (4) and terminal '1'and '4' gets closed and terminal '2' and '3' get opened.
In a preferred embodiment under this invention we have used two micro-switches for 30minutes and 50 minutes operation for one of the equipment to which timer device is made use of. Circuit of the micro switches given in fig 4, which is self-explanatory. But by varying the arc length of the rise portion and dwell portion of Bottom cam (17) as well as by varying the number of Micro-switches, we can preset different timings for the timer to activate the equipments to which it is connected, based on the end use requirement.
In a preferred embodiment of our invention, provision exists to indicate whether the timer is fully wound or not. The fully wound condition is considered as safe for operation (un armed) when we use the timer in Electro Explosive Devices. Once the On-off Knob (1) is put ON, the spring starts unwinding and at the end of the operation terminal 1&4 of the Micro switches (3&4) get closed and terminals 2&3 gets opened there by the Electro Explosives Devices becomes unsafe (armed) to handle.
This safety indication feature is achieved by means of Safety lever (5) that is connected to the Top cam (9) by suitable means such as spring and locking pin and the rotary movement of Top cam (9) is converted to lateral movement of the Safety lever (5).
Although the invention has been described in considerable detail with particular reference to certain preferred embodiments, thereof, variations and modifications can be effected within the spirit and scope of the invention as described herein above and as defined in the appended claims.

We claim
1. An Improved Timer Device comprising Top cam (9) and Bottom cam (17) interconnected by means of Center arm (10); the Main spring (16); Center wheel (15); Gear train (8) having a plurality of gears & pinions and escapement mechanism, wherein the Center arm (10) with means for operating the timer to set in motion, is capable of rotating to wind the Main spring (16) which serves as the power source with the provision of On-off knob (1) connected to On-off lever(13) capable of releasing that Balance wheel (14) kept under torque to oscillate the escapement mechanism of the Gear train (8), where in the Bottom cam(17) having dwell and rise portion operating a plurality micro switches mounted on a Base plate (2) adaptable to the respective equipment.
2. An improved timer device as claimed in claim-1, where in the bottom cam (17) having dwell and rise portion capable of operating a plurality of micro switches (3 &4) connectable to devices such as Electro Explosive Device (EED), where in means are provided to shortens the ignition device and isolate the power supply from the electronic circuit and isolate the power supply at the start of the operation of the timer device and vice-versa at the end of the operation.
3. An improved timer device as claimed in claim-1, the gear train (8) is provided with increased pinion addendum to avoid Gear train (8) jam and slippage and is capable of attaining high rate of oscillations more than 3 oscillations per second.
4. An improved timer device as claimed in claim-1, wherein material for Main spring (16), Gear train (8), gear train top & bottom plates (11 & 12), top & bottom cams (9 &17) are selected from non magnetic self lubricating material having less thermal coefficient enabling to magnetic influence, lubricating oil due point temperature effect and minimize thermal effects during its operation and is capable to function at extreme temperatures

selected from -55° C to + 70° C, most preferably from -35°C to +55°C and with long shelf life.
5. An improved timer device as claimed in claim-1, where in Gear train (8)
mechanism is provided with maximum possible transverse play for gear
and pinion assembly capable of avoiding jamming of gears and pinions
due to thermal strains developed in Gear train mounting plates (11 &12).
6. An improved timer device as claimed in claim-1, wherein power source is
Main spring (16) designed to give a torque ranging from 2.5kg-cm to 10kg-
cm preferably 3 to 6kg-cm and most preferably 5kg-cm.
7. An improved timer device as claimed in claim-1, where in provision exists
for actuating by way of two independent means for pressing the On off
knob (1) by applying a force of more than 1 kg force towards down word
direction and rotating to any desired angle in clockwise direction.
8. An improved timer device as claimed in claim-1, Top cam (9) is provided
with Safety liver mechanism having Safety lever (5) provided with locking
pin and spring and is capable of converting the rotary motion of the Top
cam (9) to lateral motion of the Safety lever (5).
9. An improved timer device as claimed in claim-1, wherein it is capable to
set for multiple timings by means of plurality of Micro switches and varying
the arc length of the dwell and rise portion of the Bottom cam (17).
10. An improved timer device as claimed in claim-1, wherein timer device
substantially here in described with reference to and illustrated in figure
1,2,3 and 4 of the accompanying drawings.