Miniature electrical generators and power sources

A power source for generating electrical power. The power source including: a shaft rotatably disposed relative to a structure; an elastic element having one end attached to the shaft and another end attached to the structure for storing potential energy upon rotation of the shaft in a first angular direction; a generator operatively coupled relative to the shaft; and a retaining mechanism movable between an engaged position for retaining the shaft from rotating in a second angular direction opposite to the first angular direction and a power generating position permitting the shaft to rotate in the second angular direction. Wherein, when the retaining mechanism is moved to the power generating position, the stored potential energy in the elastic element is converted to kinetic energy to rotate the shaft which in turn rotates the generator coupled to the shaft so as to produce electrical power.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present disclosure relates generally to miniature dynamo type electrical generators and corresponding power sources, and more particularly, to miniature electrical generators and power sources for projectiles fired by guns, mortars and the like or hand grenades and the like.

2. Prior Art

Chemical reserve batteries have long been used in various munitions, weapon systems and other similar applications in which electrical energy is required over relatively short periods of times. In addition, unique to the military is the need for munitions batteries that may be stored for up to twenty years without maintenance. Reserve batteries are batteries designed to be stored for years, even decades, without performance degradation. Reserve batteries are stored in an inert state and can be activated within a fraction of a second with no degradation of battery capacity or power. Typical Reserve batteries are thermal batteries and liquid reserve batteries.

The typical liquid reserve battery is kept inert during storage by keeping the electrolyte separate from the electrodes. The electrolyte is kept in a glass or metal ampoule inside the battery case. Prior to use, the battery is activated by breaking the ampoule and allowing the electrolyte to flood the electrodes. The ampoule is broken either mechanically or by the high g shock experienced from being shot from the cannon.

Thermal batteries represent a class of reserve batteries that operate at high temperatures. Unlike liquid reserve batteries, in thermal batteries the electrolyte is already in the cells and therefore does not require a distribution mechanism such as spinning. The electrolyte is dry, solid and non-conductive, thereby leaving the battery in a non-operational and inert condition. These batteries incorporate pyrotechnic heat sources to melt the electrolyte just prior to use in order to make them electrically conductive and thereby making the battery active. Thermal batteries have long been used in munitions and other similar applications to provide a relatively large amount of power during a relatively short period of time, mainly during the munitions flight. Thermal batteries have high power density and can provide a large amount of power as long as the electrolyte of the thermal battery stays liquid, thereby conductive.

Reserve batteries are expensive to produce, primarily since the process of their manufacture is highly labor intensive and involve mostly manual assembly. For example, the process of manufacturing thermal batteries is highly labor intensive and requires relatively expensive facilities. Fabrication usually involves costly batch processes, including pressing electrodes and electrolytes into rigid wafers, and assembling batteries by hand. The reserve batteries are encased in a hermetically-sealed metal container that is usually cylindrical in shape. In munitions, thermal batteries may be initiated during launch via inertial or electrical igniters, or may be initiated later during the flight via electrical igniters. The liquid reserve batteries are usually activated during launch by breaking the electrolyte ampoule.

Chemical reserve batteries, including thermal batteries and liquid reserve batteries, are generally very expensive to produce, require specialized manufacturing processes and equipment and quality control, and are generally required to be developed for each application at hand.

All existing and future smart and guided weapons, including gun-fired projectiles, mortars, and small and large gravity dropped weapons, require electric energy for their operation. For many fuzing operations such as fuzing “safe” and “arm” (S&A) and sensory functionalities and many other “smart” fuzing and initiation functionalities, the amount of electrical energy that is needed is low and may be as low as 10-50 mJ, and even less. In fact, with such electrical energy levels, low-power electronics could be easily powered to provide the above fuzing or the like functionalities. The amount of power required to operate many other electronic components, for example those used for diagnostics and health monitoring purposes, or for receiving a communicated signal or the like is also very small and can be readily achieved with electrical energy in the above range. In all such applications, particularly for powering electronics for fuzing and other similar “safe” and “arm” functionalities, it is highly desirable to have low-cost and safe alternatives to chemical reserve batteries. This is particularly the case for the above applications since it is generally difficult to produce very small, miniature, reserve batteries of any kind.

In addition, in certain munitions applications a relatively small amount of electrical energy, sometimes as low as 10-50 mJ is required before firing to bring up at least a portion of the onboard electronics and the like and/or to transfer firing and other information into the munitions memory and the like. In such applications, electrical energy is currently provided either by onboard electronics or by electrical energy transferred to onboard capacitors using for example induction coupling or optical or radio frequency means before the firing. In certain applications liquid reserve or thermal batteries inside the munitions are initiated to provide the required electrical energy. All such options makes the design and operation of the munitions complex, add significantly to their cost and generally require a significant amount of space onboard. The latter option also has the disadvantage of if the round is not fired within a relatively short amount of time, the initiated reserve battery can no longer provide the required amount of power and the round becomes inoperative.

A need therefore exists for alternatives to chemical reserve batteries for low power applications such as pre-fire data transfer and hold powering and for powering fuzing electronics and other similar functionalities when the required electrical energy levels are low, and for powering industrial and commercial products such as self-powered health monitoring and emergency sensor.

For munitions applications, such miniature electrical generators and power sources, hereinafter referred to as power sources, have to have a very long shelf life of up to 20 years; be low cost; and be capable of being scaled to the required power level requirements, shape and size, with minimal design and manufacturing change efforts.

A need also exist for miniature power sources for munitions applications such as gun-fired munitions, mortars and grenades in which their potential energy storage springs (elastic elements) have no stored potential energy and the required potential energy is stored in them as a result of launch acceleration.

A need also exists for miniature power sources for munitions and other industrial and commercial applications in which potential energy is stored in energy storage spring (elastic) elements of the device a priori. Hereinafter, all such mechanical potential energy storage elements (whether helical or other types of springs or elastic elements or structural flexibility) will be referred to simply as springs. A release mechanism is then used to release the stored potential energy and allow it to be converted to electrical energy via a mechanical to electrical energy conversion device such as a continuously rotating or a linear or rotary vibratory magnet and coil generator device.

A need also exists for miniature power sources that are manually operated through a push button type mechanisms provided on the surface of munitions to generate electrical energy for their pre-fire or the like powering or through said push button or toggle or other similar type of on-off mechanisms to generate electrical energy for powering various industrial and commercial low power devices. The mechanical energy to electrical energy conversion elements of such power sources may be based on magnet and coil generators or piezoelectric or any other such energy conversion devices.

An objective is to provide non-chemical miniature electrical generators and corresponding power sources for the aforementioned and the like low power applications. In these power sources, mechanical potential energy can be stored in the power source and used to generate electrical energy upon occurrence of certain events, such as firing of a projectile by a gun or by the release (or ejection) of a gravity dropped weapon or through certain manual operation. This is in contrast to chemical reserve batteries in which stored chemical energy is released upon a certain event (such as firing by a gun or by an electrical charge), thereby allowing the battery to provide electrical energy.

Another objective is to provide non-chemical power sources are miniaturized and are manually operated through a push button type mechanisms provided on the surface of munitions to generate electrical energy for pre-fire or the like powering or through said push button or toggle or other similar type of on-off mechanisms to generate electrical energy for powering various industrial and commercial low power devices.

Here, a means of storing potential mechanical energy can be elastic deformation, such as in various types of spring elements and/or the structural flexibility of the structure of the system in which it is used such as the structure of a projectile or the like, and not potential energy due to gravity. It is, however, appreciated by those skilled in the art that potential energy may also be stored by other means such as by pressurizing compressible gasses such as air. The mechanical energy may be stored a priori in the said mechanical potential energy storage springs or be manually input at the time of use. The mechanical potential energy stored in the power source storage springs can then be released via certain mechanisms to be described either upon the occurrence of certain intended event(s), such as firing and/or spinning of a projectile or releasing of a gravity-dropped weapon or other events appropriate to the device employing the power source or manually through certain mechanisms. The released potential energy can then be used to generate electrical energy using well known methods such as by the use of active materials based elements such as piezoelectric elements or magnet and coil type generators.

To this end, the mechanical stored potential energy is preferably transferred to a flywheel as kinetic energy which is then used to generate electrical energy through a continuous rotation of a rotary magnet and coil generator to achieve high mechanical energy to electrical energy conversion efficiency. Gearing mechanisms may also be employed to increase speed of generator rotation to further increase the power source energy conversion efficiency.

Alternatively, the mechanical stored potential energy is used to cause vibration of a mass-spring system. The vibration energy is then transformed into electrical energy by one of the aforementioned piezoelectric, coil and magnet or the like elements.

A second object is to provide methods and mechanisms for releasing the stored potential energy in the power sources with a priori stored mechanical potential energy. Such mechanisms include various hand operated mechanisms or various external event initiated mechanisms. Examples of such event initiated mechanisms include those operated due to gun firing acceleration; deceleration of gun-fired projectile (the so-called set-forward acceleration); the process and/or mechanism of releasing (e.g., gravity dropping) the weapon from its mounting rack or the like; pulling out or ejection of a releasing element (e.g., a releasing pin or wire); actuation or breaking of a stop element or the like via detonation of small charges; etc.

For the power sources employing piezoelectric elements for converting mechanical energy of vibration to electrical energy, methods described for mass-spring systems used in the piezoelectric based power generators described in the U.S. Pat. Nos. 7,231,874 and 7,312,557 can generally be used in the construction of the disclosed power sources, particularly for those mechanical reserve power sources to be used in gun-fired projectiles and mortars which are subject to very high-G firing acceleration levels.

In addition, in such mechanical reserve power sources, the piezoelectric elements (stacks) employed to convert mechanical energy of vibration to electrical energy may also be used as sensors to measure setback and set-forward acceleration levels, target impact impulse levels and direction, the time of such events and more as described in the U.S. Pat. No. 8,701,599 or 8,266,963 or 8,205,555 or 8,191,475 or 7,762,192 or 7,762,191.

SUMMARY OF THE INVENTION

Accordingly, a method for the development of miniature electrical generators and corresponding power sources is provided. In these power sources, mechanical potential energy is stored a priori or during activation phase such as by pushing of a button or actuating of a switching mechanism in elastic elements such as springs. The stored potential energy is then released manually or upon occurrence of certain event via certain mechanisms, such as gun firing of a projectile or gravity dropping of a weapon or throwing of a hand grenade or through actuation of certain mechanism for example manually or via detonation of a small charge or the like. The released energy can then be transformed into kinetic energy of a flywheel or the like to rotate a magnet and coil rotary generator or to vibration energy of a mass-spring system, which is then harvested by mechanical to electrical energy conversion elements such as piezoelectric elements or magnet and coil elements.

Accordingly, methods and apparatus for storing potential energy in the power sources, and methods and apparatus for releasing the stored potential energy manually or upon the occurrence of several events are provided. The mechanical potential energy may be stored a priori or generated during the power source activation phase.

The event upon which the stored mechanical potential energy of the disclosed mechanical power sources is released and the start of electrical power generation can be used to provide “safe” and “arm” (S&A) or other similar safety functionality, particularly when the power source is used for powering fuzing means. The generated electrical energy may also be used to power electronic circuitry and/or logics used to provide additional “safe” and “arm” (S&A) functionality for fuzing or other similar applications. Accordingly, methods and apparatus for the “safe” and “arm” (S&A) or other safety functionality with and without electronics circuitry and/or logics are also provided.

When using mass-spring type vibrating elements in the power-source, the device mass-spring elements may be configured to be excited also by the vibration and rotary oscillations of the munitions during the flight, thereby allowing the power source to generate additional electrical energy. The power source may also be provided with the means to generate vibration of its mass-spring element during the flight due to aerodynamics forces, e.g., by the means to generate flutter.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT

Although this invention is applicable to numerous and various types of devices, it has been found particularly useful in the environment of generating power onboard munitions such as gun-fired munitions, mortar and grenades. Therefore, without limiting the applicability of the invention to generating power onboard such munitions, the invention will be described in such environment. However, those skilled in the art will appreciate that the present methods and devices can also be used in generating power in other devices, including commercial and industrial sensors and other low power electronic devices for direct powering and/or for charging appropriate electrical energy storage devices such as rechargeable batteries or capacitors.

The basic design and operation of the first embodiment10of the mechanical reserve power source of the present invention is shown in the schematic ofFIG. 1. The mechanical reserve power source10is considered to be mounted in a structure11of the power source. The mechanical reserve power source10consists of a shaft12, which is free to rotate in the bearing13mounted in the device structure11. The shaft12is also provided with the end piece14to which it is rigidly attached and which can be an integral part of the shaft12. A torsion (such as a power type) spring15is also attached on one end to the structure11of the power source10and on the other end41to the shaft12as shown inFIG. 1. As can be seen inFIG. 1, a shaft16is provided that engages the end piece14of the shaft12via a one-way clutch17. The shaft16is attached to the input of a magnet and coil dynamo18, which is also attached to the structure11of the power source10. A flywheel19can also be provided on the shaft16as shown inFIG. 1to provide for a smooth operation of the power source10. The end piece14is provided with a recess20which may be engaged by the tip21of the link22as shown inFIG. 1. The link22is in turn attached to the link23via the pin joint24. The link23is in turn attached to the power source structure11by the pin joint25.

The power source10is originally assembled as follows. Before engaging the tip21of the link22in the recess20of the end piece14, the shaft12of the power source is rotated—in this case in the clockwise direction as observed from the top—to preload the torsion power spring to a desired level. The tip21of the link22is then engaged with the recess20of the end piece14, thereby locking the end piece14to the structure11of the power source and preventing it to unwind the torsion power spring15. As a result, mechanical potential energy is stored in the torsion power spring15. The assembled power source10is now ready for use in the intended device.

The reserve power source embodiment10is designed to be manually initiated. To this end, the user would at the desired time rotate the link23in the counterclockwise direction as shown by the arrow26, for example, by applying a force to the link23in the direction of the arrow27, thereby causing the tip21of the link22to exit the recess20in the end piece14. As a result, the end piece14is now free to be rotated by the preloaded torsion power spring15. The one-way clutch17is directed such that the resulting clockwise (as viewed from the top) rotation of the end piece14would transmit the torsion power spring torque to the shaft16. As a result, the potential energy stored in the torsion power spring15is transferred mostly to the flywheel19and the shaft16and the rotor of the generator18as kinetic energy, while the magnet and coil generator18would begin to transform the transferred kinetic energy to electrical energy to power the intended devices. Once the potential energy stored in the torsion power spring15is transferred to the assembly of the shaft16, flywheel19and the generator18, the one-way clutch17allows the shaft16to continue to rotate with respect to the end piece14. The kinetic energy transferred to the assembly of shaft16, flywheel19and rotor of the generator18will then keep on being transformed into electrical energy until the kinetic energy is exhausted and the assembly would come to a stop. In general, for the sake of maximizing the mechanical to electrical energy conversion efficiency, the generated electrical energy is desired to be used as generated or stored in an electrical energy storage device, such as a capacitor or a rechargeable battery.

It will be appreciated by those skilled in the art that once the end piece14is released by the aforementioned actuation of the release link23, the links22and23are desired to be prevented from interfering with the operation of the moving components of the reserve power source10. To this end, stops28and30may be provided to limit the motion of the link23. A preloaded tensile spring29that connects the links22and23as shown inFIG. 1may also be provided to pull the link22towards the link23upon disengagement with the end piece14and away from interfering with the motion of the other components of the power source10. A preloaded compressive spring31can also be provided to bias the link23towards the stop30to prevent its accidental actuation and initiation of power generation as previously described.

Another feature that may be readily added to the reserve power source embodiment10ofFIG. 1is the means of proving a “safety pin” which would lock the initiating link23to the structure11of the power source. The “safety pin” can, for example, be readily included at one of the stops28or30, as shown in the close up view ofFIG. 2in which this region of the reserve power source10ofFIG. 1is drawn with the added “safety pin” feature. In this added feature shown inFIG. 2, the link23is provided with an extension33, which is provided with a hole35. A matching extension32is also provided on the structure11of the reserve power source10and is also provided with a hole34, which in the configuration shown inFIGS. 1 and 2, i.e., before the previously described initiation of the power source10to generate electrical energy, lines up with the hole35. A “safety pin”36can then be passed through the two holes34and35to lock the link23to the structure11of the reserve power source10. The “safety pin”36can be provided with a finger hole end37for the user to readily pull out the pin36and allow the user to force the link23to release the end piece14and as was previously described to initiate the power source10to generate electrical energy.

In the above description of the reserve power source embodiment10, a preloaded compressive spring31is indicated to be used to bias the link23towards the stop30to prevent its accidental actuation and initiation of power generation. It will be, however, appreciated by those skilled in the art that the use of the aforementioned “safety pin”36eliminates the need for the preloaded compressive spring31for this purpose. The preloaded compressive spring31may still be desirable so that between the time of “safety pin” removal and the intended reserve power source initiation, the link23is not accidentally actuated to initiate the electrical energy generation.

In an alternative design, the spring31,FIGS. 1 and 2, may be a preloaded tensile spring. As a result, as the “safety pin”36is pulled out as previously described, then the preloaded tensile spring31would pull on the link23and thereby release the end piece14as was previously described and initiate electrical energy generation process.

In reserve power source embodiment10ofFIGS. 1 and 2, a mechanism consisting of links22and23is shown to be used to lock the end piece14to prevent the potential energy stored in the preloaded torsion power spring15from being released and initiate electrical energy generation. It is however appreciated by those skilled in the art that numerous other similarly functioning and manually operated mechanisms may also be used to perform the same function. Such mechanisms would only need to provide the means of pulling a locking pin, wedge, ball, etc., from engagement with the end piece14and thereby allowing the preloaded torsion power spring to freely rotate the end piece. As an example, as can be seen in the schematic ofFIG. 3, the tip38of the “safety pin”39(36inFIG. 2) itself may be used directly to lock the end piece14to the structure11of the reserve power source by being inserted in the recess20of the end piece. Then as the user pulls out (or back) the “safety pin”39, such as via the finger hole end40, the end piece14is released and the reserve power source10begins to generate electrical energy. As another example, a button (not shown) may be provided on the structure11of the reserve power source10, which when pushed would apply a force in the direction of the arrow27to rotate the link23in the direction of the arrow26, thereby causing the end piece14to be released and the reserve power source to begin to generate electrical energy as was previously described.

It will be appreciated by those skilled in the art that the any one of the above designs of the reserve power source10illustrated inFIGS. 1-3, and particularly the design with a “safety pin”36,FIG. 2, with a preloaded compressive spring31is highly suitable for use in munitions such as hand grenades that are equipped with electronic and related devices that require electrical energy to operate. In such an application, the user must first pull out the “safety pin”36, and then press the link (lever)23to initiate electrical energy generation.

In the reserve power source embodiment10, with the “safety pin” shown in the schematic ofFIG. 3, the “safety pin”39is designed to be manually removed by the user to initiate electrical energy generation. Alternatively, the means of pulling “safety pins” of different type, for example those similar to the ones inFIG. 1orFIG. 2or others with locking wedge elements, locking balls, etc., may be removed (pulled back or rotated away or the like) via detonation of a small charge. An example of such a “safety pin” removal mechanism actuated by the detonation of a small gas generating charge is shown in the schematic ofFIG. 4. Here the mechanism is constructed as a cylinder42which is attached to the housing11of the reserve power source10. The cylinder42houses a piston43to which a piston rod44is attached. In the configuration shown inFIG. 4, the tip47of the piston rod44is shown to be in engagement with the recess20on the end piece14, thereby locking it to the structure11of the reserve power source10. The cylinder is also provided with an electrically initiated gas generating charge45, with the initiation wires46. Upon initiation of the gas generating charge45, gas pressure builds up in the cylinder42on the side of the gas generating charge45, thereby forcing the piston43to move away from the end piece14, thereby causing the tip47of the piston rod44to disengage the end piece, thereby allowing the reserve power source to begin to generate electrical energy.

In the “safety arm” release mechanism ofFIG. 4, an electrically initiated gas generating charge is shown to be used. It is, however, appreciated by those skilled in the art that an inertially initiated gas generating charge may also be employed. Such inertially initiated devices are well known in the art (see e.g., U.S. Pat. Nos. 7,587,979; 7,587,980; 7,437,995; 8,042,469, 8,061,271; 7,832,335; 8,418,617; 8,651,022 and 8,550,001), and for munitions applications they could be designed to initiate due to the firing setback acceleration or firing set forward acceleration or due to target impact shock loading or firing spin acceleration or spinning velocity induced centripetal acceleration.

Another embodiment of a power source50is shown in the schematic ofFIG. 5. All components of the power source50are identical to those of the embodiment10ofFIG. 1, except for the modification to the end piece48(14in the embodiment ofFIG. 1) and its release mechanism. In addition, the torsion power spring15(such as a high stiffness torsion spring—hereinafter referred to as torsion spring) is not preloaded, i.e., the power source has no stored mechanical potential energy prior to the initiation process to be described. As a result, the power source50is no longer a “reserve” type power source.

The cross-sectional view A-A,FIG. 5, showing the indicated changes to the end piece48and the basic method and mechanism of storing mechanical potential energy in the torsion spring15and its release is shown inFIG. 6.

As can be seen in the cross-sectional view A-A ofFIG. 6, the end piece48(14in the embodiment ofFIG. 1) is provided with a similar recess52(20in the embodiment ofFIG. 1) and is also provided with an actuating lever54. A locking element49is also provided that can slide back and forth in the sliding bearing51provided in the structure11of the power source50. In the configuration shown inFIGS. 5 and 6, the tip53of the locking element49is in engagement with the recess52of the end piece48, thereby locking it to the structure11of the power source and preventing the end piece and the shaft12from rotating. In addition, in the configuration shown inFIGS. 5 and 6, the torsion spring15is not preloaded and the power source would have zero stored mechanical potential energy to convert to electrical energy. The latter feature is highly desirable in devices where safety is of great importance such as in various types of munitions, such as hand grenades.

In operation, the user rotates the lever54and thereby the end piece48in the clockwise direction as shown by the arrow61, for example by applying a force in the direction of the arrow62to the lever54as shown inFIG. 6. The resulting counterclockwise rotation of the shaft12,FIG. 6, causes the torsion spring15,FIG. 5, to be loaded and mechanical potential energy be stored in the torsion spring. As the lever54is further rotated in the counterclockwise direction and increasing amount of mechanical potential energy is stored in the torsion spring15. The lever54is provided with an extension element55which is provided with a curved surface profile58,FIGS. 5 and 6. The locking element49is also provided with an engagement top piece56,FIGS. 5 and 6, with an inclined surface57as shown inFIG. 6. As can be observed inFIG. 5, the extension element55is sized such that it can pass over the surface of the locking element49(in front of the engagement top piece56) but its surface58would otherwise engage the surface57of the engagement top piece56. Then as the lever54is rotated in the clockwise direction, at some point, the tip59of the extension element55moves over the frontal surface of the locking element49, followed by engagement of the surface58with the surface57. Then as the lever54is rotated further in the clockwise direction, the curved surface58will force the locking element49to move to the right,FIG. 6, thereby disengaging the tip53of the locking element49from the recess52of the end piece48. The torsion spring15will then be free to rotate the shaft12and thereby begin the previously described process of generating electrical energy.

It is appreciated by those skilled in the art that in the power source embodiment50ofFIGS. 5 and 6, a preloaded compressive spring element63,FIG. 6(not shown inFIG. 5for clarity) may also be added to bias the tip53of the locking element49into the engagement with the recess52of the end piece48. Such a biasing spring may be desirable in cases in which the device may be subjected to incidental shock loading or vibration or the like that may cause the power source to be accidentally initiated.

In the embodiments ofFIGS. 1 and 5, a torsion power spring and a torsion spring were used, respectively, to store potential mechanical energy for generation of electrical energy. It is, however, appreciated by those skilled in the art that in applications in which the shaft12is rotated only a small fraction of a full turn, probably at most 90-120 degrees, which is mostly the case for the power source embodiment ofFIG. 5, then other types of springs such as regular or preloaded tensile or compressive springs or their combination or almost any other type of elastic element may also be similarly used for the purpose of storing mechanical potential energy.

Another embodiment of power source60is shown in the schematic ofFIG. 7. In this embodiment60, a “push button” element65is provided that can slide up and down in the structure64of the power source. The push button element65is provided with side elements66, which are fixed to the push button element65and can slide freely in the guides67provided in the structure64of the power source, as shown inFIG. 7and in the cross-sectional view B-B of the power source shown inFIG. 8. Stop element70which is fixed to the structure64of the power source is also provided to limit downward displacement of the push button element65. At least one preloaded compressive spring71is also provided to bias the push button element upwards. At least one stop72can also be provided to limit upward displacement of the push button element65.

In a cavity68provided in the push button element65,FIG. 7, is provided a relatively large pitch threaded portion73, which mates with a matching threaded surface74on a shaft69as shown inFIG. 7. The shaft69is also provided with a free end76, over which is mounted a flywheel77via a one way clutch78. The flywheel77is then connected to the input shaft81of a magnet and coil type electrical energy generator82via a coupling element79which is fixedly attached to the flywheel77, as shown in the schematic ofFIG. 7.

The internal and external threaded surface73and74, respectively, are designed with relatively large pitch and are provided with enough clearance so that by pressing the push button element65down in the direction of the arrow75, the shaft69is rotated with minimal resistance (other than inertial resistance of the flywheel, coupling79and rotor of the generator82; generator82torque and frictional forces).

In operation, the user presses on the push button element65rapidly by applying a force in the direction of the arrow75,FIG. 7. Downward translation of the push button element65causes the shaft69to rotate, transmitting the rotation through the one-way clutch78to the flywheel77and through the coupling79to the input shaft81of the electrical generator82. The one-way clutch is configured such that while the shaft69is being rotated by the push button element as it moves down in the direction of the arrow75, the motion is transmitted to the assembly of the flywheel77, and that the flywheel77is free to continue to rotate once the downward translation of the push button element has ended. The user can press the push button element65down hard (apply a relatively large force) to transfer a relatively large amount of energy to the flywheel77and its assembly. The user can also press the push button element65down until its motion is stopped by the stops70. The user will then allow the at least one preloaded compressive spring71to push the push button element65back to its uppermost position shown in the schematic ofFIG. 7.

It will be appreciated by those skilled in the art that the work down by the user by displacing the push button element65downwards certain distance by applying certain amount of force is transferred to the assembly of the flywheel77, coupling79and the rotor of the generator82as kinetic energy—less the friction and other losses and the amount of electrical energy generated during the process. The kinetic energy stored in the assembly is then transformed to electrical energy by the generator82. In the meantime, the user can keep on pressing down on the push button element65and letting it bounce back by the at least one preloaded compressive spring71, each time adding more kinetic energy to the flywheel and its assembly for conversion to electrical energy.

In the schematic ofFIG. 7regular screw threads are shown to be provided on the mating internal and external surfaces73and71, respectively. It is, however, appreciated by those skilled in the art that to increase the efficiency of the power source embodiment60in converting the work done by the user to electrical energy by reducing the friction related losses between the contacting surfaces73and71, one may instead use a ball screw. Ball screws are well known in the art and are commonly used in machinery to reduce friction losses in power screws.

It will be appreciated by those skilled in the art that the basic design and operation of the “push button” type power source embodiment is illustrated by the schematic ofFIG. 7for the sake of clearly identifying each component of the power source and describing their function and the operation of the overall power source. In practice, however, it is generally highly desirable to have a very compact power source. For example, the at least one springs71may be designed as a single conical spring that is assembled around the shaft69and collapses as the push button element65is pressed down into a single layer. The flywheel77and the rotor of the generator may also be fabricated as one unit in a pancake type generator design to significantly reduce the size of the power source for a prescribed amount of energy generation requirement. In practice, similar approaches are readily implemented on the designs of the other embodiments described previously and later in this disclosure to achieve significantly more compact power source designs.

In the power source embodiment60, no mechanical energy storage element (spring or other type of elastic element) is used for a priori storage of mechanical potential energy. As a result, the power source60is a simple power source and not a “reserve” type power source. This feature of this power source of having zero stored mechanical energy prior to the electrical energy generation process to be described is highly desirable in devices where safety is of great importance, such as in various types of munitions, such as hand grenades.

An alternative design80of the power source embodiment60is shown in the schematic ofFIG. 9. This alternative embodiment80is also a “push button” type. In this embodiment80, a “push button” element83with an attached shaft84which can slide up and down in the bearing85provided in the structure86of the power source80. While sliding up and down in the bearing85, the shaft84is prevented from rotation with respect to the structure86of the power source by a key member87, which is engaged with the guide99in the structure86of the power source80, as is shown in the cross-sectional view C-C ofFIG. 10. A slightly preloaded compressive spring88is provided around the shaft84between the push button element83and the surface90of the structure86of the power source80to bias the said push button element away from the surface90. The shaft84is also provided with a stop element89which limits the biasing action of the spring88as shown in the schematic ofFIG. 9.

The shaft84is provided with a section91, which is threaded as a high pitch screw. Mating with the threaded screw is the nut element92, over which is mounted a flywheel93, via a one-way clutch94. A thrust bearing94ais provided under the nut element92to support the nut element92against the structure86of the power source80. In this embodiment of the present invention, the flywheel93is fabricated with outside gearing that engages with a pinion95, which is mounted on a shaft96of a magnet and coil electrical generator97. The use of the gearing allows the rotary speed of the electrical generator97to be increased and thereby increasing the amount of electrical power that the generator97can produce.

In operation, the user presses on the push button element83by applying a force in the direction of the arrow98,FIG. 9. Downward translation of the push button element83and the shaft84causes the threaded section91to rotate the nut element92. The nut element92in turn will rotate the flywheel93through the one-way clutch94. The flywheel93(outer gear) will in turn rotate the pinion95, which would directly rotate the rotor shaft96of the electrical generator97. Electrical energy thereby begins to be generated by the electrical generator97. The one-way clutch94is configured such that while the nut element92is being rotated by the threaded section91of the push button shaft84as the push button83is being translated down in the direction of the arrow83, the rotation of the nut element92is transmitted to the flywheel93, and the flywheel93is free to continue to rotate once the downward translation of the push button element has ended.

The user can press the push button element83down hard (apply a relatively large force) to transfer a relatively large amount of energy to the flywheel93. The user can also press the push button element83down until its motion is stopped by the stops89. The user will then allow the preloaded compressive spring88to push the push button element83back to its uppermost position shown in the schematic ofFIG. 9.

It will be appreciated by those skilled in the art that the work down by the user by displacing the push button element83downwards a certain distance by applying a certain amount of force is transferred to the assembly of the flywheel93, pinion95, the nut element92and the rotor of the generator97as kinetic energy—less the friction and other losses and the amount of electrical energy generated during the process. The kinetic energy stored in the assembly is then transformed to electrical energy by the generator97. In the meantime, the user can keep on pressing down on the push button element83and letting it bounce back by the spring88, each time adding more kinetic energy to the flywheel and its assembly for conversion to electrical energy.

Yet another embodiment100of the power source embodiment60is shown in the schematic ofFIG. 11. This alternative embodiment100is also a “push button” type. The design and operation of this embodiment is the same as the embodiment80ofFIGS. 9 and 10and is indicated with the same numerals, except for the method and components for transferring motion and mechanical energy from the flywheel93to the electrical energy generator type employed. In the embodiment100ofFIG. 11, a coupling element101is fixedly attached to the flywheel93. The coupling element101is annular in shape to prevent interference with the motion of the nut element92, the one-way clutch94and the threaded portion91of the push button shaft84. The coupling element101is then directly connected to the rotating side of the pancake type magnet and coil electrical generator102, which is in turn fixed to the structure86(body) of the power source100. The pancake type electrical generator102type used is the one with open center to allow for the motion of the threaded portion91of the push button shaft84and which is provided with a thrust or other bearing that can support an axial load in reaction to the force applied to the push button element83to drive the push button shaft84down in the direction of the arrow98.

The operation of the “push button” power source100is the same as that of the embodiments60and80ofFIGS. 7 and 9, respectively. In operation, the user presses on the push button element83by applying a force in the direction of the arrow98,FIG. 11. Downward translation of the push button element83and the shaft84causes the threaded section91to rotate the nut element92. The nut element92in turn will rotate the flywheel93through the one-way clutch94. The flywheel93will in turn rotate the electrical generator102via the coupling101. Electrical energy thereby begins to be generated by the electrical generator102. The one-way clutch94is configured such that while the nut element92is being rotated by the threaded section91of the push button shaft84as the push button83is being translated down in the direction of the arrow83, the rotation of the nut element92is transmitted to the flywheel93, and that the flywheel93is free to continue to rotate once the downward translation of the push button element has ended.

In the above power source embodiments50,60,80and100ofFIGS. 5, 7, 9 and 11, respectively, a spring (elastic) element is deformed by direct rotation of a link (power source50ofFIG. 5) or translation of an element (power sources60,80and100) by the user. The motions would in turn deform a spring (elastic) element and store mechanical potential energy in the spring (elastic) element. Alternatively, a number of linkage and/or gear mechanisms or other similar mechanical motion or force amplifying or reducing or otherwise modifying mechanisms may be provided to increase the performance of the power source, i.e., the amount of electrical energy and/or power that it can generate and/or reduce its size or vary its finished shape to certain available or desirable shape.

It is appreciated by those skilled in the art that the electrical energy generated by the above embodiments may either be used directly to power certain electrical or electronic circuitry and/or to store in certain electrical energy storage device, such as capacitors, super-capacitors or rechargeable batteries. In almost all such cases the electrical energy generated by the power sources have to be regulated by electronic and logic circuitry to provide electrical power to the intended electrical power consuming devices. The block diagram of the resulting typical electrical power system is shown inFIG. 12.

InFIG. 12, the block103is intended to indicate one or more of the disclosed power sources10,50,60,80and100ofFIGS. 1, 5, 7, 9 and 11, respectively. The electrical energy generated by the power source(s) is then regulated by the electronic and logic circuitry104and used directly in the electrical energy consuming device105and/or used to charge the electrical energy storage device such as a rechargeable battery or capacitor106. In general, a related charging circuitry107is also required for safe charging of any electrical energy storage device106.