SYSTEMS AND METHODS FOR EJECTING BATTERIES FROM AN ELECTRIC FLYING VEHICLE

Abstract

One method for ejecting a battery from an electric flying vehicle includes monitoring one or more batteries providing power to the electric flying vehicle during a flight, determining when at least one of those batteries is operating as a hazardous battery posing a safety risk to the electric flying vehicle while in flight, activating an ejection system disconnecting the hazardous battery from a chassis of the electric flying vehicle, and ejecting the hazardous battery from the electric flying vehicle during the flight. The system operating this process may include a sensor that monitors the operating state of the batteries, a controller in communication with the sensor for determining when the one or more of the batteries is hazardous, and an actuator opening enough of the housing to permit ejection of the hazardous battery out from within the electric flying vehicle midflight.

Claims

1. A method for ejecting a battery from an electric flying vehicle, comprising the steps of: monitoring one or more batteries providing power to the electric flying vehicle during a flight; determining when at least one of the one or more batteries providing power to the electric flying vehicle is operating as a hazardous battery posing a safety risk to the electric flying vehicle while in flight; activating an ejection system disconnecting the hazardous battery from a chassis of the electric flying vehicle; and ejecting the hazardous battery from the electric flying vehicle during the flight.

2. The method of claim 1, including the step of deploying a landing system coupled with the ejected hazardous battery to soften its landing on the ground.

3. The method of claim 2, wherein the deploying step includes the step of monitoring an altitude of the ejected hazardous battery with an altimeter and wherein the landing system comprises a parachute.

4. The method of claim 2, including the step of comparing a geographic location of the ejected hazardous battery to a geographic location of the electric flying vehicle, and performing the deploying step after the ejected hazardous battery is a predetermined distance away from the electric flying vehicle.

5. The method of claim 2, including the step of timing activation of the deploying step as a factor of time after the hazardous battery is ejected from the electric flying vehicle.

6. The method of claim 5, wherein the timing step includes the step of tripping a mechanical clock or starting an electronic clock after the ejected hazardous battery loses connectivity with the electric flying vehicle.

7. The method of claim 1, wherein the activating step includes the step of de-coupling the hazardous battery from a bus interface and wherein the ejecting step includes the step of opening a cargo door.

8. The method of claim 7, wherein the bus interface comprises a quick-release cable.

9. The method of claim 1, wherein the monitoring step includes steps for sensing an operating state of each of the one or more batteries and communicating the operating state of each of the one or more batteries to a central controller for comparison to a set of predetermined safe operating conditions.

10. The method of claim 9, including the step of communicating the operating state for one or more of the batteries to a human interface device in real-time.

11. The method of claim 1, wherein the activating step includes the step of unlocking a battery compartment housing the hazardous battery from a set of ejection rails at least partially coupled to the chassis of the electric flying vehicle.

12. The method of claim 11, including the step of rolling the unlocked battery compartment out from a fuselage of the electric flying vehicle along the set of ejection rails.

13. The method of claim 11, including the step of reorienting the set of ejection rails by approximately 90 degrees, whereby the unlocked battery compartment housing the hazardous battery laterally rolls out from a side hatch of the electric flying vehicle.

14. The method of claim 1, wherein the ejecting step includes the step of triggering a spring, a propellant, a controlled explosive, or a hydraulic actuator propelling the hazardous battery out from within the electric flying vehicle.

15. The method of claim 1, wherein the ejecting step includes the step of dropping the hazardous battery from a fuselage, a wing, or an externally mounted engine compartment.

16. The method of claim 1, including the step of automatically adjusting at least one flight parameter of the electric flying vehicle in real-time while simultaneously ejecting the hazardous battery to maintain a flight trajectory of the electric flying vehicle.

17-27. (canceled).

28. A method for ejecting a battery from an electric flying vehicle, comprising the steps of: monitoring one or more batteries providing power to the electric flying vehicle during a flight; determining when at least one of the one or more batteries providing power to the electric flying vehicle is operating as a hazardous battery posing a safety risk to the electric flying vehicle while in flight; activating an ejection system unlocking a battery compartment housing the hazardous battery from a set of ejection rails coupled with the electric flying vehicle; rolling the unlocked battery compartment out from the electric flying vehicle along the set of ejection rails; and ejecting the hazardous battery out from a fuselage, a wing, or an external chamber of the electric flying vehicle.

29. The method of claim 28, including the steps of: de-coupling the hazardous battery from a bus interface of the electric flying vehicle; tripping a mechanical clock or an electronic clock after the ejected hazardous battery loses connectivity with the electric flying vehicle; and deploying a landing system coupled with the ejected hazardous battery as a factor of time after the hazardous battery is ejected from the electric flying vehicle.

30. The method of claim 28, including the steps of: sensing an operating state of each of the one or more batteries; communicating the operating state of each of the one or more batteries to a central controller for comparison against a set of predetermined safe operating conditions; and adjusting at least one flight parameter of the electric flying vehicle in real-time while simultaneously performing the ejecting step to maintain a relatively consistent flight trajectory.

31. The method of claim 28, including the step of reorienting the set of ejection rails by approximately 90 degrees, whereby the unlocked battery compartment housing the hazardous battery laterally rolls out from a side hatch of the electric flying vehicle.

32. A method for ejecting a battery from an electric flying vehicle, comprising the steps of: monitoring one or more batteries providing power to the electric flying vehicle during a flight; determining when at least one of the one or more batteries providing power to the electric flying vehicle is operating as a hazardous battery posing a safety risk to the electric flying vehicle while in flight; disconnecting the hazardous battery from a bus interface comprising a quick-release cable coupled with at least a portion of a housing of the electric flying vehicle, the housing comprising a fuselage, a wing, or an external chamber; ejecting the hazardous battery from the electric flying vehicle during flight; comparing a geographic location of the ejected hazardous battery to a geographic location of the electric flying vehicle; and deploying a landing system coupled with the ejected hazardous battery after the ejected hazardous battery is a predetermined distance away from the electric flying vehicle.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0015] The accompanying drawings illustrate the invention. In such drawings:

[0016] FIG. 1 is a flowchart illustrating a process for safely ejecting batteries from an electric aircraft during a midflight emergency;

[0017] FIG. 2 is a top plan view of one embodiment of an electric flying vehicle carrying batteries within a battery compartment in a fuselage of the electric flying vehicle;

[0018] FIG. 3 is a side view of the electric flying vehicle of FIG. 2;

[0019] FIG. 4 is a cross-sectional view of the electric flying vehicle of FIGS. 2 and 3, taken about the line 4-4 in FIG. 2, and more specifically illustrating a rear cargo door ejection system;

[0020] FIG. 5 is an front elevation view of a battery compartment for use with the electric flying vehicles disclosed herein;

[0021] FIG. 6 is a cross-sectional view similar to FIG. 4, further illustrating a under carriage ejection door in an alternative electric flying vehicle;

[0022] FIG. 7 is a rear elevation view of the alternative electric flying vehicle of FIG. 6, further illustrating a battery compartment positioned immediately above a pair of under carriage ejection doors;

[0023] FIG. 8 is a top plan view of another alternative electric flying vehicle incorporating a pair of wing-mounted battery compartments;

[0024] FIG. 9 is a cross-sectional view taken about the line 9-9 in FIG. 8, further illustrating the internal structure of one of the wing-mounted battery compartments;

[0025] FIG. 10 is a top plan view of another alternative electric flying vehicle incorporating an engine-mounted battery compartment; and

[0026] FIG. 11 is a cross-sectional view taken about the line 11-11 in FIG. 10, further illustrating the internal structure of the engine-mounted battery compartment.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0027] As shown in the exemplary drawings for purposes of illustration, the present invention for a method for safely ejecting batteries from an electric flying vehicle midflight (100) is generally illustrated with respect to the flowchart shown in FIG. 1, and FIGS. 2-4 and 6-11 illustrate various embodiments of an electric flying vehicle 20, 20, 20, 20 incorporating an emergency response system for carrying out the aforementioned method (100). In general, the method (100) disclosed herein may provide a fast (e.g., real-time) and efficient way to mitigate the loss of life and/or property (e.g., both on-board the electric flying vehicle 20, 20, 20, 20 and/or on the ground below) in response to an on-board emergency (e.g., a fire) related to the use and/or operation of one or more batteries carried by the electric flying vehicle 20, 20, 20, 20 as a power source to operate one or more engines used in connection therewith. In this respect, in the event of such an on-board emergency, the method (100) may utilize a series of sensors, controllers, processing units, and/or system mechanics to quickly and safely assist in ejecting one or more hazardous or damaged batteries out from within the electric flying vehicle 20, 20, 20, 20. Such methods (100) are designed to preserve the safety and structural integrity of the electric flying vehicle 20, 20, 20, 20 midflight until it can land, while, at the same time, being designed to safely deploy the one or more damaged batteries to the ground, especially since the methods (100) disclosed herein are designed to eject damaged and/or hazardous batteries midflight. The electric flying vehicle disclosed herein, including the electric flying vehicles 20, 20, 20, 20, may include aircraft, airplanes, roto-craft, etc.

[0028] More specifically, one aspect of the method (100) is the step of monitoring the health of the batteries within the electric flying vehicle 20, 20, 20, 20in real-time (102). In this respect, as illustrated, e.g., in the cross-sectional views of FIGS. 4 and 6, the electric flying vehicle 20, 20 may include a sensor 22 that couples about a communication line 24 to a bus interface 26 adjacent one or more battery compartments 28, each housing and/or retaining one or more batteries 30 therein. The sensor 22 may also couple to a system central controller 29 as illustrated, e.g., with respect to the electric flying vehicles 20, 20 in FIGS. 9-11. Here, the central controller 29 may receive and/or interpret signals generated by one or more of the sensors 22 to determine whether one or more of the batteries 30 should be ejected to improve safety. The central controller 29 may make safety decisions in real-time and communicate and/or operate the other systems such as one or more emergency ejection sensor data processors and/or human interface devices that may provide human readable status information (e.g., on an LCD screen or the like) and/or controls for manually operating the equipment disclosed herein simultaneously in real-time. For example, the central controller 29 may send and/or receive information with the sensors 22 along the communication line 24, and then selectively de-couple and disconnect the affected batteries from the bus interface 26 (e.g., by a cable quick-release or other quick-release hardware known in the art) in real-time as needed and/or desired during an emergency. Of course, the sensors 22, the communication lines 24, the bus interface 26, and/or the central controller 29 may be wired and/or located with other known electrical equipment or wiring within a body 32 of any of the electric flying vehicles 20, 20, 20, 20. The sensors 22 should be positioned somewhat proximate the batteries 30, such as within a fuselage 34 as illustrated best in FIGS. 4 and 6 with respect to the electric flying vehicles 20, 20, within one or both of a pair of wings 36 as illustrated best in FIG. 9 with respect to the electric flying vehicle 20, or within one or multiple of a set of engine housings 38 as best illustrated in FIG. 10 with respect to the electric flying vehicle 20. The sensor 22 may include one or more sensors designed to monitor battery health, such as a smoke sensor, a fire sensor, a light sensor, a heat sensor, a stress/strain sensor, or another mechanical or chemical sensor known in the art.

[0029] Specifically with respect to FIGS. 2-4, the battery compartment 28 retaining one or more of the batteries 30 therein may be located within the fuselage 34 of the electric flying vehicle 20. In this embodiment, the battery compartment 28 is illustrated resting on a set of ejection rails 40 located on a base 42 of the fuselage 34. During normal flight operation, the batteries 30 in the battery compartment 28 remain coupled with the bus interface 26 positioned proximate a nose 44 of the electric plane 20. Here, the batteries 30 may serve as fuel for delivering electricity to drive one or more engines that operate a propeller 45 (FIGS. 2, 8, and 10) to maintain the electric flying vehicle 20 in flight. Moreover, the battery compartment 28 may also be locked relative to the set of ejection rails 40 in the position generally illustrated in FIG. 4 to substantially reduce (and possibly eliminate) relative movement of the batteries 30 therein during flight.

[0030] Although, in the event one or more of the sensors 22 determines that one or more of the batteries 30 is in a hazardous condition as part of step (104), the sensor 22 may relay a signal to de-couple the bus interface 26 from the damaged or hazardous batteries 30. Moreover, the battery compartment 28 housing the damaged or hazardous batteries may be unlocked as part of a step (106) for safely ejecting the one or more hazardous batteries from the electric flying vehicle 20 midflight. At the same time, the central controller 29 may open the fuselage 34, such as by moving a rear cargo door 46 from a closed position as illustrated in FIG. 3 to an open position as illustrated in FIG. 4. When in the open position illustrated in FIG. 4, the now unlocked battery compartment 28 housing the damaged and/or hazardous batteries may be able to slide or roll rearward within the fuselage 34 along the ejection rails 40, such as by way of gravity. Although, additional mechanisms such as springs, propellants, explosives, or mechanical apparatus (e.g., armatures operated by hydraulics) may be used to more quickly eject the battery compartment 28 from the electric flying vehicle 20 once the rear cargo door 46 is deployed to the open position illustrated in FIG. 4. Such ejection may occur as part of step (108).

[0031] FIG. 5 is a rear plan view of the battery compartment 28 having a pair of opposing feet 48 that allow the battery compartment 28 to traverse over the ejection rails 40 and out through the rear cargo door 44 of the electric flying vehicle 20 as part of step (108). FIG. 5 also illustrates that at least one of the batteries 30 may be mounted within the frame of the battery compartment 28. Furthermore, a parachute 50 or another speed safety mechanism (e.g., speed brakes, decelerators, etc.) may couple to the battery compartment 28 in a position (e.g., as illustrated in FIG. 5) to deploy after the battery compartment 28 ejects out from the fuselage 34. The parachute 50 may assist in preserving safe deployment by decelerating the rate at which the damaged ejected batteries descend to the ground. In some embodiments, the parachute 50 may include a more traditional canopy structure (e.g., including a vent and/or pilot chute). Moreover, the parachute 50 may also be integrated with one or more balloons and/or cushions that selectively inflate upon ejection, at some point midflight, or when nearing the ground, to assist in deceleration during freefall and to assist in softening impact when the ejected batteries reach the ground.

[0032] Moreover, a parachute control module 52 mounted to the battery compartment 28 may collect data to determine when it is safe to deploy the parachute 50, as part of the deployment step (110). Here, the parachute control module 52 may include its own sensor such as an altimeter that determines the altitude of the ejected battery compartment 28 in real-time before it lands on the ground. Although, of course, the parachute control module 52 may include one or more other sensors and/or controls to determine the status of the parachute 50 (e.g., unarmed, armed, deployed, failure, etc.) and/or the status of the ejected battery compartment 28 (e.g., acceleration, altitude, speed, etc.), such as an integral or separately located parachute telemetry transceiver (e.g., an Emergency Locator Transceiver (ELT)) that relays a signal related to the location, status, etc. of the parachute 50 to a third party receiver (e.g., one or more recovery teams). Moreover, the parachute control module 52 may also include a clock that delays deployment of the parachute 50 based on some predetermined duration after the ejected battery compartment 28 loses contact with the electric flying vehicle 20 (e.g., once ejected out the back of the open rear cargo door 46). In one embodiment, the clock may be mechanically tripped on the way out the rear cargo door 46. In another embodiment, the clock may be electronically tripped, such as by way of losing wireless connection with an onboard receiver and/or transmitter coupled to the central controller 29. To this end, after deployment as part of step (110), the parachute 50 deploys at a desired altitude and speed to ensure the ejected battery compartment 28 safely lands on the ground as part of step (112). In an upright landing, the battery compartment 28 would land resting on the feet 48. Of course, deploying the parachute 50 during this process helps soften the landing of the battery compartment 28, which may otherwise be relatively heavy if it were to hit the ground on freefall. At this point, the method (100) ends as part of step (114) when the battery compartment 28 safely lands on the ground.

[0033] The electric flying vehicle 20 may continue to derive energy from one or more batteries that remain within the fuselage 38 and/or other energy sources (e.g., a back-up generator or some other fuel reserve), to keep the propeller blades running long enough so the electric flying vehicle 20 has enough fuel to make an emergency landing nearby.

[0034] In an alternative embodiment, the electric flying vehicle 20 may include at least one ejection door 54 built into a bottom portion of the fuselage 34 as illustrated, e.g., in FIGS. 6 and 7. Here, during the monitoring step (102), when the sensor 22 determines that at least one battery compartment 28 needs to be ejected from the electric flying vehicle 20 as part of step (104), the bus interface 26 may again de-couple from the affected batteries 30 and the battery compartment 28 may unlock from being coupled to the fuselage 34. At the same time, the central controller 29 may simultaneously open one or more of the ejection doors 54, as part of the step for safely ejecting the one or more hazardous batteries from the electric flying vehicle 20 midflight (106). Here, FIG. 6 illustrates that the electric flying vehicle 20 may include one of the ejection doors 54 while FIG. 7 illustrates another embodiment wherein the electric flying vehicle 20 could have a pair of opposing ejection doors 54 built into the fuselage 34. A pair of vertical guide rails 56 upstanding from the base 42 of the fuselage 34 may generally constrain forward/rearward and/or side-to-side movement of the battery compartment 28 within the fuselage 34. In this respect, the vertical guide rails 56 may maintain the position of the battery compartment 28 above the one or more ejection doors 54, 54. As such, once the one or more ejection doors 54, 54 open, the now unlocked battery compartment 28 located thereabove may effectively drop out from within the electric flying vehicle 20 as part of step (108). The method for then deploying the parachute 50 coupled to the ejected battery compartment 28 in step (110) and then safely landing the ejected battery component 28 on the ground as part of (112) is similar to that disclosed above with respect to FIGS. 2-5.

[0035] The rear cargo door 46 and/or the one or more ejection doors 54, 54 may be operated mechanically to eject the battery compartment 28 therefrom, or ejection may be aided by way of propellants, hydraulics, springs, explosives, or may simply operate by gravity as disclosed above.

[0036] FIGS. 8-9 illustrate another alternative embodiment of the electric flying vehicle 20 wherein the one or more battery compartments 28 housing the one or more batteries 30 reside within the pair of wings 36, as opposed to residing within the fuselage 34, as disclosed herein with respect to FIGS. 2-4 and 6-7. In this embodiment, the central controller 29 may couple with any of the sensors 22 (e.g., by the communication line 24 or wirelessly) and/or the bus interface 26 (not shown in FIG. 8) along the body 32 of the electric flying vehicle 20, e.g., along with other electrical wiring and/or electrical components as may be known in the art. Although, the one or more sensors 22 should still be located proximate the batteries 30 within each of the wings 36 so that the one or more sensors 22 can monitor the health of the batteries 30 in real-time, and especially midflight. The wings 36 may include an integral ejection door 54, similar to the embodiments disclosed above with respect to the ejection doors 54, 54 illustrated with respect to FIGS. 6-7. In this respect, when the central controller 29 determines that one or more of the batteries 30 are in a hazardous condition as part of step (104), the central controller 29 may begin to safely eject the one or more hazardous batteries 30 from the electric flying vehicle 20 as part of step (106) by first de-coupling the affected batteries 30 from the bus interface 26 and unlocking the respective battery compartment 28 retaining the affected batteries 30. At the same time, the respective ejection door(s) 54 in the wing 36 of the affected battery 30 may move from a normal closed position as illustrated in FIG. 8 to an emergency ejection open position as illustrated in FIG. 9. Once open, the one or more hazardous batteries 30 may be ejected from the respective wing 36 of the electric flying vehicle 20 as part of step (108), such as by way of simply dropping the affected battery compartment 28 out from within the respective wing 36 by gravity now that the ejection door 54 is open. The process for deploying the parachute 50 of the ejected battery compartment 28 as part of step (110) and then safely landing the parachuted ejected battery compartment 28 on the ground as part of step (112), to end the process (114), is substantially the similar to that disclosed above with respect to FIGS. 2-5.

[0037] In an alternative embodiment, the ejection doors 54 illustrated in FIG. 9 may be replaced with pylons, booms, or other mechanical apparatus that sufficiently retain, and if needed, release the battery compartment 28 from the respective wing 36 in the event that one or more of the associated batteries 30 retained thereby become hazardous to the continued safe operation of the electric flying vehicle 20.

[0038] FIGS. 10 and 11 illustrate another alternative embodiment of the electric flying vehicle 20 wherein the battery compartments 28 housing the batteries 30 reside within the set of engine housings 38 illustrated therein. In this respect, as generally discussed above, each of the engine housings 38 may include one or more of the sensors 22 (generally illustrated in FIG. 10) for monitoring the health of the one or more batteries 30 as part of step (102). FIG. 9 illustrates that the one or more sensors 22 may couple to the central controller 29 by way of the communication line 24, but the sensors 22 may also communicate therewith wirelessly. Similarly, the central controller 29 may communicate (e.g., by way of a wire line or wireless connection) to the bus interface 26. In this respect, when any of the sensors 22 determine that one or more of the batteries 30 is in a hazardous condition as part of step (104), the system may initially de-couple the affected battery from the bus interface 26 as part of the step for safely ejecting the one or more hazardous batteries from the electric flying vehicle 20 midflight (106). At the same time, the battery compartment 28 housing the affected battery may unlock one or more ejection doors 54 thereunder. Here, the ejection doors 54 are integrated with the engine housings 38 as opposed to being integrated with the wings 36 (FIGS. 8-9) and/or being integrated with the fuselage 34 (FIGS. 6-7). As such, the unlocked battery compartment 28 housing the affected batteries may then be ejected from the engine housing 38 as part of step (108). This may occur by way of gravity or another ejection mechanism as disclosed herein, to more quickly move the battery compartment 28 out from within the engine housing 38 of the electric flying vehicle 20. As with the other embodiments disclosed herein, the next steps for deploying the parachute 50 coupled with the ejected battery compartment 28 as part of step (110) and safely landing the parachuted ejected battery compartment 28 on the ground as part of step (112), thereby ending the method (114), are similar to those disclosed above.

[0039] Additional aspects of the systems and methods for safely ejecting batteries from an electric aircraft midflight might include further integration of the sensor(s) 22, the communication line(s) 24, the bus interface(s) 26, and/or the central controller 29 with other systems onboard any of the electric flying vehicles 20, 20, 20, 20 disclosed herein. For example, the systems and methods as disclosed herein could be integrated with a retractable landing gear system to ensure that a set of landing gear 58 (FIGS. 3 and 9) does not interfere with ejection of the damaged or hazardous batteries. Another example may be to integrate the central controller 29 with in-flight control software to mitigate the effects on flight dynamics when battery ejection occurs (e.g., a rapid and/or significant change to the weight and/or balance of the electric flying vehicle 20, 20, 20, 20).

[0040] In other aspects of the embodiments disclosed herein, one or more of the batteries 30 and/or one or more of the battery compartments 28 retaining the one or more batteries 30 may be ejected forwardly or rearwardly, such as from one or more of the wings 36 and/or from one or more of the engine housings 38, may be ejected laterally from one or more sides of the fuselage 34, and/or may be ejected vertically by an ejection system akin to that of an ejection seat or ejector seat, depending on the flight dynamics at the time the batteries are ejected from the electric flying vehicle.

[0041] More specifically with respect to lateral ejection, the electric flying vehicle may include one or more ejection hatches formed laterally therein. Here, the ejection hatches may operate similar to the rear cargo door 46 and/or any of the ejection doors 54, 54, 54, namely pivoting or rotating from a normal closed position to an emergency open position whereby one or more of the batteries 30 and/or one or more of the battery compartments 28 retaining one or more damaged or hazardous batteries may be safely laterally ejected from the electric flying vehicle. In this embodiment, the ejection rails 40 may be reoriented 90 degrees, e.g., so any unlocked battery compartments will have a propensity to slide laterally toward and out the ejection hatches during an emergency. As with other embodiments disclosed herein, propellants and/or controlled explosives may aid in moving the respective battery compartment and/or batteries laterally for roll out or push out ejection through the side-accessible ejection hatches. Although, of course, other mechanisms disclosed herein, such as springs or mechanical apparatus (e.g., armatures operated by hydraulics), may be used to more quickly eject the battery compartment and/or batteries from the electric flying vehicle by way of the ejection hatches.

[0042] For vertical ejection, one or more panels of the body 32 may pivot open, pop open, or otherwise dislodge therefrom to provide an access opening to the fuselage 34 for purposes of vertical ejection of one or more of the batteries 30 and/or one or more of the battery compartments 28 retaining the one or more batteries 30 from the electric flying vehicle. Again, propellants, controlled explosives, springs, mechanical apparatus (e.g., armatures operated by hydraulics), and/or other mechanisms that may aid ejection as disclosed herein, may quickly and efficiently pop up and eject the damaged or hazardous battery out from the electric flying vehicle 20 through the now open panel in the body 32.

[0043] Although several embodiments have been described in detail for purposes of illustration, various modifications may be made without departing from the scope and spirit of the invention. Accordingly, the invention is not to be limited, except as by the appended claims.