阅读说明：本技术 教导机器人的安全系统及方法 (Safety system and method for teaching robot ) 是由 王培睿 郭耀庭 黄识忠 于 2020-06-15 设计创作，主要内容包括：本发明公开一种教导机器人的安全系统及方法,预设各运行模式相对应的安全模块及安全功能,建构各运行模式适合的安全系统,模式切换装置切换机器人的运行模式,启用相对应模式预设的安全模块及安全功能,确保在各种运行模式都能维持专有的安全模块及安全功能,以提升安全性。(The invention discloses a safety system and a method for teaching a robot, which presets safety modules and safety functions corresponding to each operation mode, constructs safety systems suitable for each operation mode, switches the operation modes of the robot by a mode switching device, starts the safety modules and the safety functions preset in the corresponding modes, ensures that the special safety modules and the safety functions can be maintained in each operation mode, and improves the safety.)

1. A safety system for teaching a robot, comprising:

the robot is provided with a plurality of toggle joints, one end of each toggle joint is a movable tail end, and an actuator and a position sensor are arranged in each toggle joint;

a controller connected to the robot, controlling the actuator and the position sensor, and moving the end of the robot;

an enabling device connected to the controller;

the safety module is arranged in the controller, is electrically or communicatively connected with the energy device, and sends out an electrical or communication signal according to the on-off state of the energy device, the off state enables the robot to enter a safety state, and the on state cancels the safety state of the robot;

the safety function unit is arranged in the controller and is electrically or communicatively connected with the safety module, and when the safety function of the monitored robot exceeds a preset limit, the safety module enables the robot to enter a safety state;

the mode switching device is electrically or communicatively connected with the controller, the safety module and the safety function unit and is used for switching the running mode of the robot;

the mode switching device switches between at least one manual pull mode and an automatic mode or a manual low-speed mode or a manual high-speed mode of the robot, and the safety module and the safety function unit start the safety module and the safety function which are preset corresponding to each operation mode.

2. The safety system for teaching a robot of claim 1, wherein the pull mode requires pressing the enabling device to pull the robot.

3. The safety system for teaching a robot as claimed in claim 1, wherein the safety module is electrically or communicatively connected to the position sensor of each of the toggles of the robot, receives signals from the position sensors and monitors the robot.

4. The safety system for teaching a robot as claimed in claim 3, wherein the safety module comprises at least one safety state type, wherein the zero type safety state is a power-off shutdown function, and when entering the safety state, the power of the actuator is directly turned off, the one type safety state is a progressive power-off shutdown function, and when entering the safety state, after issuing a deceleration command to the controller, the power of the actuator is turned off after the deceleration motion of the robot is achieved for a fixed time, and the second type safety state is a non-power-off shutdown function, and when entering the safety state, after issuing a deceleration command to the controller, the deceleration motion of the robot is achieved for a fixed time, the static monitoring safety function is turned on, the position sensor is continuously monitored, and when the motion of the robot is monitored, the power of the actuator is turned off.

5. The safety system for teaching a robot of claim 1, wherein the safety function unit initiates at least one or more of the following safety functions: an angle limit of the wrist, a spatial position limit of the robot tip, a force limit, or a speed limit.

6. The safety system for teaching a robot as claimed in claim 1, wherein the mode switching means is provided in a teach pendant of the robot or is externally connected to the controller.

7. The safety system for teaching a robot as claimed in claim 1, wherein the mode switching means is a multi-position knob, a mode is indicated by a knob position, or a mode is displayed with a light signal.

8. The safety system for teaching a robot of claim 1, wherein the mode switching means is a pure software key, or a combination of hardware keys, or a combination of software and hardware keys.

9. A safety method of teaching a robot, comprising:

presetting safety modules corresponding to the operation modes;

presetting safety functions corresponding to each operation mode;

carrying out a switching mode;

checking that the switching mode is a hand pulling mode;

entering the hand-pulling mode;

starting the hand-pulling mode to preset a corresponding safety module and a safety function, and enabling the shutdown robot to enter a safety state;

enabling the enabling device;

and detecting the opening state of the enabling device, releasing the safety state of the robot, and teaching the robot to work.

10. The safety method of teaching a robot according to claim 9, wherein after the work is performed,

and checking that the robot finishes the operation, ending the operation, and returning to the switching mode to continue the operation if the robot does not finish the operation.

11. The method as claimed in claim 10, wherein the checking mode is an automatic mode, and the automatic mode is started to preset a corresponding safety function, so as to monitor the robot for performing the robot automatic operation.

12. The method as claimed in claim 9, wherein when the checking mode is a manual low speed mode or a manual high speed mode, the manual low speed or manual high speed mode is activated to preset a corresponding safety function, monitor the robot, and perform a robot teaching or running task.

13. The method as claimed in claim 12, wherein when the manual low-speed mode, the manual high-speed mode, or the automatic mode is switched to the hand-pulling mode, the robot automatically records a breakpoint of a running program, and starts a preset safety module and safety function of the hand-pulling mode, and after the hand-pulling teaching of the robot is performed, the robot switches back to each running mode, and then continues to run the program from the breakpoint.

14. The safety method of teaching a robot of claim 9, wherein entering the hand-pulling mode at least continuously presses the enabling device, releases the safety state, and enables the hand-pulling function.

15. The method as claimed in claim 9, wherein the safety module and safety function, whether enabled or not and the limit value are preset according to the requirements of each operation mode of the robot.

Technical Field

The present invention relates to a safety system and method for a robot, and more particularly, to a safety system and method for a robot to perform teaching and protection for a user when the robot switches between an automatic mode and a hand-pulling mode or a non-hand-pulling mode.

Background

With the vigorous development of the robot technology, although the factory uses the robot to assist the operators to rapidly perform the processing, assembling and manufacturing operations and improve the production efficiency of the factory, the safety of the operators is seriously affected by whether the robot can normally operate, so that strict safety standard specifications are set by various countries to maintain the operation safety of the robot.

Referring to fig. 5, in order to teach the robot 1 to operate in the prior art, a pull button 2 is disposed at an end of the robot 1, the pull button is generally designed to be operated by Hold to Run (Hold to Run), or is a key on software, and the pull button 2 is electrically or communicatively connected to a controller 3 of the robot 1. When the teach pendant 4 sets the robot 1 to be in the teaching mode, the user presses the Hand button 2 to signal the controller 3 to switch the robot 1 from the stationary state to the Hand mode (Hand Guiding). The hand pulling mode in the prior art has various ways, for example, the robot 1 is controlled to follow the hand pulling movement by knowing the force applied to each joint or the hand pulling force applied to the end through the encoder of the actuator in each wrist 5 of the robot 1 and the calculation and compensation of the motor current sensor. And teaching the robot 1 to operate by using the hand-pulled robot 1 to the point position recording position or the hand-pulled recording path. When the hand pull button 2 is released, the robot 1 is switched to the hand pull mode and returns to the static state.

The aforementioned teach pendant 4 of the prior art robot 1, in order to comply with the requirements of the safety standard specification ISO 10218-1, is provided with an enabling Device (Enable Device) in the teach mode to protect the cooperating users. The Enabling device 6 is usually a three-section button (3Position energy Switch) in the teach pendant 4, and its structure is designed with three pressing stages, fully released, neutral, and pressed, wherein only the neutral can enable the robot 1 to perform teaching action, and when fully released or pressed, the electric or communication is transmitted to the controller 3, the safety system 7 starts the teaching action to interrupt, so that the robot 1 stops moving, and the robot 1 is monitored by "Monitoring rest" (Stand Still Monitoring) to prevent the robot 1 from being inadvertently moved when the actuator is Still powered, if the robot is monitored to move, the safety system 7 will cut off the power of the actuator of the robot 1, so as to protect the safety of the user during teaching.

However, in the aforementioned prior art robot, in the teaching mode, a plurality of teaching operations such as hand-pulling, cooperative work, or non-hand-pulling, for example, inching, trial running, etc. are required, and each teaching operation has different safety requirements. Therefore, the robot still has a problem to be solved in the safety system and method for pulling by hand.

Disclosure of Invention

The invention aims to provide a safety system for teaching robots, which switches a plurality of operation modes of a robot through a mode switching device, and enables different safety modules and safety functions corresponding to each teaching mode to be preset by matching with an enabling device so as to conveniently switch the modes.

Another objective of the present invention is to provide a safety method for teaching a robot, which utilizes a safety module and a safety function switching robot corresponding to each preset operation mode to construct a safety system specific to each operation mode, so as to ensure the safety of a user.

Another objective of the present invention is to provide a safety method for teaching a robot, which can maintain a safety module and a safety function specific to a hand-pulling mode when various operation modes are switched to the hand-pulling mode, so as to improve the safety of a user.

In order to achieve the above-mentioned object, the present invention teaches a safety system for a robot, comprising a multi-toggle robot, one end of which is a movable end, actuators and position sensors disposed in the respective toggles, a controller connected to the controller for controlling the actuators and the position sensors, and a movable end connected to the robot, an enabling device connected to the controller, a safety module disposed in the controller and electrically or communicatively connected to the enabling device for generating an electrical or communication signal to enable the robot to enter a safety state or to disable the safety state according to a switching state of the enabling device, a safety function unit disposed in the controller and electrically or communicatively connected to the safety module, wherein when a monitored safety function of the robot exceeds a predetermined limit, the safety module enables the robot to enter the safety state, and a mode switching device electrically or communicatively connected to the controller, the safety module and the safety function unit, and when the mode switching device switches the robot to each operation mode, the safety module and the safety function unit start the safety module and the safety function preset corresponding to each operation mode.

The safety module is electrically or communicatively connected with the position sensors of all the wrist joints of the robot, and receives signals of the position sensors to monitor the robot. The safety module at least comprises the following safety state types, wherein a zero type safety state is a power-off shutdown function, when the safety state is entered, the electric power of the actuator is directly turned off, a first type safety state is a progressive power-off shutdown function, when the safety state is entered, a deceleration command is issued to the controller, after the deceleration motion of the robot is achieved within a fixed time, the power of the actuator is turned off, a second type safety state is a non-power-off shutdown function, when the safety state is entered, after the deceleration command is issued to the controller, after the deceleration motion of the robot is achieved within the fixed time, the static monitoring safety function is turned on, the position sensor is continuously monitored, when the robot is monitored to move, the power of the actuator is turned off. The safety function unit of the invention starts at least one of the following safety functions: an angle limit of the wrist, a spatial position limit of the robot tip, a force limit or a speed limit, etc.

The invention teaches that the operation modes switched by the mode switching device of the safety system of the robot comprise a teaching mode and an automatic mode, and the teaching mode comprises a hand-pulling mode, a manual low-speed mode and a manual high-speed mode. The mode switching device is arranged on a demonstrator of the robot or is externally connected by a controller. The mode switching device is a multi-position knob, and the mode is marked by the position of the knob or displayed by a lamp signal. The mode switching device can also be a pure software key, or a hardware key combination, or a software and hardware key combination.

The invention teaches a safety method of a robot, presets a safety module and a safety function corresponding to each operation mode, and presets whether the safety module and the safety function are started or not and a limit value according to the requirements of each operation mode of the robot. The method comprises the steps of switching a mode, checking whether the switched mode is a teaching mode, for example, a manual low-speed mode or a manual high-speed mode, entering the teaching mode, starting the teaching mode to preset a corresponding safety module and a safety function, stopping the robot to enter a safety state, enabling an enabling device, detecting the opening state of the enabling device, releasing the safety state of the robot, and teaching the robot. And if the robot finishes the operation, ending the operation, and if the robot does not finish the operation, returning to the switching mode to continue the operation.

When the switched mode is checked to be the automatic mode, the corresponding safety function preset in the automatic mode is started, the robot is monitored, and the robot automatically operates. And when the switched mode is checked to be the hand-pulling mode, entering the hand-pulling mode, at least continuously pressing the enabling device, releasing the safety state and enabling the hand-pulling function. When the manual slow mode, the manual high-speed mode or the automatic mode is switched to the hand-pulling mode, the robot automatically records the breakpoint of the running program and starts the safety module and the safety function preset in the hand-pulling mode, and after the hand-pulling teaches the robot to work, the robot switches back to each running mode and continues to run the program from the breakpoint.

Drawings

FIG. 1 is a schematic view of a safety system of a robot taught by the present invention;

FIG. 2 is a schematic diagram of the control functions of the security system of the present invention;

FIG. 3 is a schematic diagram illustrating mode switching by the mode switching device according to the present invention;

FIG. 4 is a flow chart of a safety method of the present teaching robot;

fig. 5 is a schematic diagram of a hand-pulled teaching robot in the prior art.

Description of the symbols

10 safety system

11 robot

12 controller

13 demonstrator

14 Security Module

15 safety function unit

16-energy generation (energy generation) device

17 mode switching device

18 wrist joint

19 base

20 terminal end

21 position sensor

Detailed Description

The technical means and effects of the present invention for achieving the above objects will be described below with reference to the accompanying drawings.

In order to meet the requirements of the safety standard specification ISO 10218-1, the robot is provided with the following Operation modes (Operation Mode): the automatic Mode (Auto Mode), the Manual Mode (or teaching Mode), the teaching Mode is further divided into a Manual Reduced Mode (Manual Reduced Mode) and a Manual High Speed Mode (Manual High Speed Mode), wherein the automatic Mode is defined as a robot automatic operation program for production automation operation, and a user is a production line operator; the manual or teaching mode is not used for production automation operation, but is used for programming and testing of robot programs, and a user is an automation engineer, wherein the manual low-speed mode is used for point position teaching, programming and low-speed test running, while the manual high-speed mode is specially used for test running of programs only, can achieve full-speed test running in the programs, has functions similar to those of the automatic mode but needs additional safety devices for protection, and an enabling device needs to be continuously pressed on a demonstrator for safety protection. The conventional Mode switching is performed by a Mode switching device (Mode Switch), such as three-position knob switching of AUT (automatic Mode), T1 (manual low speed Mode), and T2 (manual high speed Mode). The hand pulling function is only defined as a cooperative function in ISO 10218-1, but the hand pulling function is not specified to be used for any purpose, the cooperative robot technology is still in development stage, and safety specifications do not define hand pulling of an emerging technology. Currently, hand pulling traction has been used in various operating modes, and is commonly used in manual or teaching modes, which facilitates the automation engineer to teach points, pulling paths, and in addition, is also commonly used in automatic mode, which facilitates the production line operator to perform the following tasks: the hand pulling movement (for example, pulling the robot to the next work starting point), the hand pulling demonstration (for example, the hand pulling demonstrates the work path), the hand pulling cooperation (for example, lifting the robot and guiding the placement position by the human), the teaching behavior in the above automatic mode in the hand pulling non-safety specification, but the hand pulling operation in the automatic production process. It follows that hand-pulled traction can be used in a wide variety of automatic, manual or teaching modes.

Referring to fig. 1 to 2, fig. 1 is a schematic diagram of a safety system of a robot for teaching the present invention, fig. 2 is a schematic diagram of a control function of the safety system of the present invention, and fig. 3 is a schematic diagram of switching modes by using a mode switching device according to the present invention. In fig. 1, the safety system 10 of the present invention includes a robot 11, a controller 12, a teach pendant 13, a safety module 14, a safety function unit 15, an enabling device 16, a mode switching device 17, and the like. Wherein the robot 11 has multiple toggles 18 with a fixed base 19 at one end and a movable tip 20 at the other end. The robot 11 is connected to a controller 12, and the controller 12 contains a safety module 14 and a safety function unit 15. The controller 12 controls the end 20 of the mobile robot 11 by controlling the actuators and position sensors 21 in each wrist 18. The controller 12 is connected to the teach pendant 13 for editing the program of the robot 11 or operating the robot 11. The enabling device 16 of the present invention can be disposed on the teach pendant 13 or on the robot 11, such as the terminal 20, or the user can be externally connected to the independent enabling device 16 by the controller 12, and the enabling device 16 can be disposed at any one or more of the above positions. The mode switching device 17 may be built in the robot demonstrator 13 or a mode switching device 17 externally connected to the controller 12 by a user.

In fig. 2, the security module 14 and the security function unit 15 are electrically or communicatively connected to the enabling device 16, the mode switching device 17 and the position sensor 21 via the controller 12. The enabling device 16 has functions of ON state (ON) and OFF state (OFF) operations, and when the enabling device 16 is in the ON state (ON), the safety module 14 cancels the safety state of the robot 11, and when the enabling device 16 is in the OFF state (OFF), the safety module 14 stops the robot 11 to enter the safety state. The safety module 14 is electrically or communicatively connected to the position sensor 21 of each wrist 18 of the robot 11, and receives the signal from the position sensor 20 to monitor the activity status of the robot 11.

The safety module 14 stops the robot 11 and enters a safety state, and the zero-class safety state is a power-off stop function: when the safety module 14 determines that the robot 11 should enter a safe state, the actuator power is directly turned off. One type of safety state is the advanced power-off shutdown function: when the safety module 14 determines that the robot 11 should enter the safe state, after issuing a deceleration command to the controller 12, the actuator power is turned off after a fixed time or after observing that the robot 11 performs deceleration movement. The second type of safety state is the non-power-off shutdown function: when the safety module 14 determines that the robot 11 should enter the safety state, after issuing a deceleration command to the controller 12, after a fixed time or observing that the robot decelerates, a static Monitoring safety function (Standstill Monitoring) is turned on, the position sensor 20 is continuously monitored, and when the Monitoring robot 11 moves, the actuator power is turned off.

The safety function unit 15 of the present invention may utilize the controller 12 to monitor the robot 11 via the safety module to activate one or more safety functions, such as angle limitation of the wrist 18, spatial position limitation of the end 20 of the robot 11, Power and force limitation (Power and force limitation), or speed limitation, but includes and is not limited to the safety functions described in this embodiment. When the safety function of the monitored robot 11 exceeds the preset limit and generates an abnormality, the safety module 14 is allowed to put the robot 11 into a safe state. The various safety states of the safety module 14, the safety functions of the safety function unit 15, whether the safety module is activated or not, and the limit value are preset according to the requirements of different modes of the robot 11.

In fig. 3, the mode switching device 17 of the present invention is a multi-position knob, and can indicate the mode by the knob position on the demonstrator 13, or display the mode by a lamp. The mode switching device 17 may be a pure software key, a combination of hardware keys, or a combination of software and hardware keys, such as a hardware key press or a hardware key rotation allowing the target mode to be input, followed by the selection of the target mode by the software and the confirmation of the switched mode by the hardware. The Mode switching device 17 can switch a plurality of Operation modes (Operation modes) of the robot 11, and examples of the embodiment include an automatic Mode (a Mode), a hand-pulling Mode (H Mode), and a non-hand-pulling Mode, and the non-hand-pulling Mode includes a manual low speed Mode (T1 Mode) and a manual high speed Mode (T2 Mode), but the embodiment includes and is not limited to the Operation modes described in the embodiment.

When the user switches to the hand-pulling mode (H mode) by using the mode switching device 17, the robot 11 enters the safe state, because the user switches to the hand-pulling mode to continue to pull the robot 11, the safe module 14 presets the hand-pulling mode to the two safe states of the non-power-off shutdown function, the user at least continuously presses the enabling device 16 to release the safe state and enable the hand-pulling function, and the user pulls the robot 11 by hand to, for example, pull the robot to the next work starting point, or pull a demonstration work path, or pull a cooperative robot to lift weight and guide and place. Since the user approaches the robot 11 in the hand-pulling mode and needs strict safety protection, a plurality of safety functions such as angle limitation of the toggle joint 18 of the safety function unit 15, spatial position limitation of the end 20 of the robot 11, force limitation, and speed limitation are preset to ensure safety of the user.

The user utilizes the mode switching device 17 to switch to the non-hand-pulling manual low-speed mode (T1 mode), the safety module 14 can preset the manual low-speed mode to a progressive power-off shutdown function, for example, a type of safety state, after switching, the safety module 14 enters the safety state to ensure that the robot is stopped, and then restart the monitoring and reaction of the enabling device 16, at this time, the enabling device 16 is used to enable the teaching or teaching verification actions including but not limited to the non-hand-pulling teaching or teaching verification actions, such as performing a inch movement on each axis direction of the coordinate system of each toggle joint 18, the robot 11, and the terminal 20, or a correction action of the robot 11, or a movement of the terminal 20 to a specific point, or performing a single step of teaching programming action, etc. Since the manual low-speed mode is a non-manual mode, the user does not approach the robot 11 to work, and does not need strict safety protection, so that only safety functions such as force limitation and speed limitation of the safety function unit 15 need to be preset.

The user utilizes the mode switching device 17 to switch to the manual high-speed mode (T2 mode), because the high-speed movement is harmful to the user greatly, the safety module 14 can preset the manual high-speed mode to a zero-class safety state as a power-off shutdown function, after switching, the safety module 14 enters the safety state first, after ensuring that the robot is shutdown, the monitoring and the response to the enabling device 16 are restarted, the enabling device 16 needs to be continuously pressed to enable continuously, for example, manual running test and the like. Since the manual high-speed mode is a non-hand-pulling mode, the user does not approach the robot 11 to work, and does not need strict safety protection, only the safety functions such as speed limitation of the safety function unit 15 need to be preset.

The user switches to the automatic mode (a mode) by the mode switching device 17, and the user controls the robot 11 to perform an automatic operation by the controller 12. Because of the automatic mode, the automatic movement is harmful to the user, the safety module 14 may preset the manual high-speed mode to a zero-class safety state as a power-off and shutdown function, and may also monitor whether the automatic operation of the robot 11 is abnormal, so that when the automatic operation is a cooperative situation, a plurality of safety functions such as spatial position limitation, force limitation, and speed limitation of the end 20 of the robot 11 of the preset safety function unit 15 need to be enabled, and when the automatic mode is a non-cooperative situation, the safety function may not be enabled, so as to ensure the operation efficiency.

When the mode switching device 17 is used to switch from the manual slow mode, the manual high mode or the automatic mode to the hand-pulling mode, the robot 11 automatically records the breakpoint of the running program, and starts the safety module 14 with two types of safety states preset in the hand-pulling mode and a plurality of safety functions, so as to enable the hand-pulling function, and under the condition of maintaining the safety system special for the hand-pulling mode, after a user teaches the robot 11 to correct a new operation program by hand-pulling, the operation mode is switched back, and the program is continuously run from the breakpoint. The preset safety mode and safety function of each operation mode in the foregoing embodiment are exemplified, and the present invention includes and is not limited to the setting items of the embodiment.

As shown in fig. 4, a flow chart of a safety method of teaching a robot according to the present invention is shown. Step S1, presetting safety state types of safety modules corresponding to each teaching mode according to the requirements of various operation modes of the robot; step S2, presetting the safety function of the safety module corresponding to each operation mode according to the requirement of each operation mode of the robot; step S3, switching modes; step S4, check whether the switched mode is the automatic mode? If the switched mode is not the automatic mode, go to step S5 to check if the switched mode is the hand-pulling mode? If the switched mode is the hand-pulling mode, go to step S6 to enter the hand-pulling mode; step S7, starting the corresponding safety module preset in the mode, and stopping the robot to enter a safety state; then step S8, starting the mode to preset the corresponding safety function, and monitoring the robot; next, in step S9, the enabling device is enabled, in step S10, the on state of the enabling device is detected, the safety state of the robot is released, the robot teaching operation is performed, and then in step S11, it is checked whether the robot has completed the operation? If the robot finishes the job, go to step S12 to finish the job, if the robot does not finish the job, go back to step S3 to continue switching the modes.

In step S4, when the switched mode is checked to be the automatic mode, the method goes to step S13 to enter the automatic mode, and then goes to step S14 to start the corresponding safety module and safety function preset in the automatic mode, monitor the robot to perform the robot automatic operation, and then go back to step S11 to continue the operation.

In step S5, if the switched mode is not the hand-pulling mode, then go to step S15 to check if the switched mode is the manual high speed mode? If the switched mode is checked to be the manual high speed mode, the operation goes to step S16, the manual high speed mode is entered, and then the operation goes back to step S7, and the operation continues, if the switched mode is not checked to be the manual high speed mode, the operation goes to step S17, the manual low speed mode is entered, and then the operation goes back to step S7, and the operation continues.

Therefore, the safety system and the method for teaching the robot can switch various operation modes of the robot through the mode switching device, and can start different preset safety modules and safety functions corresponding to various teaching modes by matching with the enabling device, thereby achieving the purpose of conveniently switching various operation modes. In addition, the safety method for teaching the robot of the invention utilizes the safety modules and the safety function switching robot corresponding to the preset operation modes to construct the safety systems suitable for the operation modes, and simultaneously ensures that the safety modules and the safety functions special for the hand-pulling mode can be maintained when the operation modes are switched to the hand-pulling mode, thereby achieving the purpose of improving the safety of users.

The above description is only for the purpose of convenience of illustrating the preferred embodiments of the present invention, and the scope of the present invention is not limited to the preferred embodiments, and any modifications made according to the present invention shall fall within the scope of the claims of the present invention without departing from the spirit of the present invention.