CN202681849U - Double-wire driven glass curtain wall cleaning robot - Google Patents
Double-wire driven glass curtain wall cleaning robot Download PDFInfo
- Publication number
- CN202681849U CN202681849U CN 201220255844 CN201220255844U CN202681849U CN 202681849 U CN202681849 U CN 202681849U CN 201220255844 CN201220255844 CN 201220255844 CN 201220255844 U CN201220255844 U CN 201220255844U CN 202681849 U CN202681849 U CN 202681849U
- Authority
- CN
- China
- Prior art keywords
- double
- flexible cable
- curtain wall
- running roller
- glass curtain
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Withdrawn - After Issue
Links
Images
Landscapes
- Cleaning In General (AREA)
Abstract
The utility model relates to a double-wire driven glass curtain wall cleaning robot which is used for glass curtain wall cleaning works of mid-rise and low-rise buildings. A double-wire driving mechanism utilizes a double-wire driving mode, wires can be retracted and released through the frictional force between the wires and a roller, a driving roller is driven to rotate through roller drive motors, and the double-wire driven glass curtain wall cleaning robot can move in a cleaning plane by the aid of the coordinating retraction and releasing of double wires. A deflection angle detection mechanism is used for detecting the inclined angle between the wires and a guide slide bar and feeding back the information of the inclined angle to a microcontroller, operating speed and number of revolutions required by the roller drive motors are figured out through program calculation, thereby two roller drive motors can coordinate to move, the double-wire driven glass curtain wall cleaning robot can accurately reach to the target position along the linear track, the movement distance can be reduced, and rapidity and accuracy can be improved. The double-wire driven glass curtain wall cleaning robot is combined with the double-wire driving mechanism and the deflection angle detection mechanism, the double-wire driven glass curtain wall cleaning robot can achieve movement and rapid adjustment at any positions in the cleaning plane, and the cleaning efficiency can be improved.
Description
Technical field
The utility model relates to a kind of mobile robot who cleans the glass curtain wall wall, and it is driven by two flexible cables, is applicable to the cleaning of median low structure glass curtain wall.
Background technology
At present, main or take by cleaning the workman that hanging basket or waist tether rope finish to the cleaning of glass of building curtain wall, this mode relies on manually fully, and not only labour intensity is large, and operating efficiency is low again, and very dangerous, belongs to limit operation.The glass curtain wall cleaning machine device people that two flexible cables drive can free people from the work high above the ground environment of danger, not only can avoid the generation of accident, improves cleaning efficiency, and can beautifying urban environment, has very wide application prospect.
A kind of wall surface cleaning robot (patent No.: ZL01202018.4) of domestic Lanxing Harbin Polytechnical Uinv. Robot Tech. Co., Ltd., Beijing development, its technical characterictic is to adopt the adsorbed travel mechanism of the single sucking disc, operating efficiency is higher, cleaning performance is better, but can not cross over the obstacles such as wall window frame.
A kind of window wiping robot (patent No.: ZL00201085.2) of BJ University of Aeronautics ﹠ Astronautics's development, its technical characterictic is to adopt frame-type polypody multi-sucker absorption travel mechanism, to wall is concavo-convex certain adaptive capacity is arranged, but translational speed is low, operating efficiency is not high.
Chinese invention patent " mobile mechanism of high-rise building wall surface cleaning robot " (application (patent) number: 201010140679.6) for high-rise building wall surface, a kind of wall surface cleaning robot travel mechanism that adopts about horizontal flexible cable track and hoisting system realization, moves up and down has been proposed, level and vertical motion decoupling zero control, control algolithm is easy to realize, but be easy to occur double swerve during horizontal movement, make bumpy motion.
Researcher of the present invention finds, there is obstacles such as can not crossing over the wall window frame in similar glass curtain wall cleaning machine device people above-mentioned and of the prior art or to problems such as the concavo-convex adaptive capacity of wall are poor, and have that translational speed is low, cleaning efficiency is not high, bumpy motion and the range of movement shortcoming such as limited structurally.
Summary of the invention
The purpose of this utility model is for the deficiencies in the prior art, designs a kind of imitative spider at the bionic wall climbing cleaning robot of spatial movement mode, and it is simple and reliable for structure, and wall is adaptable, and steadily flexibly, range of movement is not subjected to the restriction of structure in motion.It has two flexible cable driving mechanisms and drift angle testing agency, relies on two flexible cables of coordination folding and unfolding to realize the movement of optional position on the glass curtain wall, can be applicable to the glass curtain wall cleaning of median low structure.
The technical scheme that its technical problem that solves the utility model adopts is:
The glass curtain wall cleaning machine device people that two flexible cables drive, its composition comprises two flexible cable driving mechanisms, drift angle testing agency.
Two flexible cable driving mechanisms of the utility model design are comprised of two flexible cables, two groups of wheels and two running roller drive motors and code-disc.Every group of wheels are comprised of two grooved pulley type rollers with four grooves, comprise an active roll and a driven running roller, active roll is descending at upper, driven running roller, two wheels left-right symmetry are installed between two gripper shoes of front and back, two active rolls link to each other with two running roller drive motors respectively, and the running roller drive motors is the direct current generator with the turbine and worm decelerator.The mode that the utility model adopts two flexible cables to drive, one end of two flexible cables is separately fixed at two tops, curtain cleaning zone, be the suspension of falling the Eight characters, improve kinetic stability of the present utility model, the other end of flexible cable is walked around from two groups of wheels of curtain cleaning robot respectively, flexible cable first from the inboard of first groove of active roll around the inboard to driven first groove of running roller, again by the outside of driven first groove of running roller around the outside to second groove of active roll, twine successively and form " 0 " word spiral.Can not interfere between the flexible cable of adjacent like this two grooves guiding, and the not any impact of groove of the retractable length of flexible cable, the utility model can reach the impact that the operating position is not subjected to the quantity of running roller groove.Turbine and worm decelerator on the running roller drive motors can make the utility model realize self-locking, guarantees the safe and reliable performance of the utility model.Two line shafts of reduction box output of direct current generator, one is the worm shaft to active roll (14) transferring power; Its two for the velocity ratio of worm shaft be the axle of 12:1, fixing code-disc thereafter is used for the revolution of measuring roller wheel drive motor.Drive the active roll rotation by the running roller drive motors, by the frictional force folding and unfolding flexible cable between flexible cable and running roller.The coordination folding and unfolding of flexible cable realizes the utility model up and down movement of direction in cleaning the plane.
The drift angle testing agency of the utility model design comprises guiding slide bar, sliding rod rack, potentiometer, potentiometer support and fairlead.The guiding slide bar is installed on connecting plate upper end, the utility model front and back by U-shaped, drift angle testing agency is risen support and guide effect, guarantees that drift angle testing agency is mobile in the horizontal direction.Sliding rod rack is realized reliably being connected by bolt with the potentiometer support, the sliding rod rack both sides have through hole, the guiding slide bar therefrom passes, sliding rod rack can slide at the guiding slide bar, be connected with potentiometer and fairlead on the potentiometer support, the effect of potentiometer is to convert the angle between flexible cable in the space and the guiding slide bar to the single-chip microcomputer receptible signal of telecommunication.The flexible cable pilot hole internal diameter of fairlead is slightly larger than the diameter of flexible cable, links to each other with potentiometer with the potentiometer connecting hole of 90 ° of its one-tenth, fixes with trip bolt.Flexible cable drives fairlead by the flexible cable pilot hole and rotates, fairlead rotates by the axle that the potentiometer connecting hole drives potentiometer, like this along with angle different between flexible cable and the guiding slide bar, can detect in real time the angle between flexible cable and the guiding slide bar, then feed back to single-chip microcomputer, through the single-chip microcomputer computing, draw running speed and revolution that the running roller drive motors needs, thereby so that two running roller drive motors can the coordinated movement of various economic factors, drive two active roll folding and unfolding flexible cables, make the utility model to the target location easy motion, and arrive the target location along straight path accurately, reduced the motion distance, improved rapidity, accuracy.
In conjunction with two flexible cable driving mechanisms and drift angle testing agency, the utility model can be implemented in movement and the rapid adjustment of cleaning the optional position in the plane, improves cleaning efficiency.The utility model is simple in structure, light and handy, and the utility model material of main part adopts aluminium alloy to make, and not only intensity is high, and lightweight.
The beneficial effects of the utility model are:
(1) detects in real time flexible cable and the angle of guiding between the slide bar by the potentiometer in the testing agency of drift angle, can calculate the up and down positional information of the utility model in cleaning the plane, thereby obtain the controlling value proportionate relationship of flexible cable folding and unfolding;
(2) designed the guiding slide bar of level, the horizontal level that adapts to potentiometer and its support changes, so that accurate real-time flexible cable and the angle that leads between the slide bar of detecting;
(3) both sides of the present utility model are driven by two flexible cables respectively, and two flexible cables are driven by direct current generator respectively again.The cooperation of the folding and unfolding length by two flexible cables realizes the utility model up and down movement in cleaning the plane;
(4) in order to increase the frictional force of flexible cable, design two flexible cables with 4 grooves and twined roller, make flexible cable walk around three circles by " 0 " word canoe, effectively increased frictional force;
(5) the simple in structure and employing aluminum alloy materials of the utility model, not only intensity is high, and lightweight;
(6) the utility model adopts two flexible cable type of drive, be suspended on the curtain wall during use, and the running roller drive motors guarantees of the present utility model safe and reliable with the turbine and worm decelerator of energy self-locking.
Description of drawings
Fig. 1 is the glass curtain wall cleaning machine device people's of of the present utility model pair of flexible cable driving front view;
Fig. 2 is the glass curtain wall cleaning machine device people's of of the present utility model pair of flexible cable driving left view;
Fig. 3 is the structure chart of the glass curtain wall cleaning machine device people's that drives of the of the present utility model pair of flexible cable drift angle testing agency;
Fig. 4 is the glass curtain wall cleaning machine device people's of of the present utility model pair of flexible cable driving flexible cable and wheels canoe schematic diagram;
Fig. 5 is the glass curtain wall cleaning machine device people's of of the present utility model pair of flexible cable driving guide sleeve structure schematic diagram.
In Fig. 1, Fig. 2, Fig. 3, Fig. 4:
1: flexible cable, 2: fairlead, 3: the guiding slide bar, 4: the turbine and worm decelerator, 5: code-disc, 6: the running roller drive motors,
7: rotary brush, 8: the brush motor, 9: water pot, 10: water spraying control valve, 11: shower nozzle, 12: driven running roller,
13: screw, 14: active roll, 15: sliding rod rack, 16: the potentiometer support, 17: potentiometer, 18:U type frame,
19: rear bearing sheet, 20: front end panel, 21: holding screw.
In Fig. 5:
22: potentiometer connecting hole, 23: set screw hole, 24: the flexible cable pilot hole.
The specific embodiment
Further specify concrete structure of the present utility model and embodiment below in conjunction with accompanying drawing.
Two flexible cable driving mechanisms of the utility model design are comprised of two flexible cables 1, two groups of wheels and two running roller drive motors 6 and two code-discs 5.Every group of wheels are comprised of two grooved pulley type rollers with four grooves, comprise an active roll 14 and a driven running roller 12, active roll 14 is descending at upper driven running roller 12, two wheels left-right symmetry are installed between front end panel 20 and the rear bearing sheet 19, two active rolls 14 link to each other with two running roller drive motors 6 respectively, and running roller drive motors 6 is the direct current generator with turbine and worm decelerator 4.The mode that the utility model adopts two flexible cables to drive, one end of two flexible cables 1 is separately fixed at two tops, curtain cleaning zone, be the suspension of falling the Eight characters, improve kinetic stability of the present utility model, the other end of flexible cable 1 is walked around from two groups of wheels of the present utility model respectively, flexible cable 1 first from the inboard of first groove of active roll 14 around the inboard to driven running roller 12 first grooves, again by the outside of driven running roller 12 first grooves around the outside to 14 second grooves of active roll, twine successively and form " 0 " word spiral.Can not interfere between the flexible cable 1 of adjacent like this two grooves guiding, and the not any impact of groove of flexible cable 1 retractable length, the utility model can reach the not impact of the quantity of groove of operating position, and namely the utility model range of movement is not subjected to the restriction of structure.Turbine and worm decelerator 4 on the running roller drive motors 6 can make the utility model realize self-locking, guarantees the safe and reliable performance of the utility model.Two line shafts of reduction box output of direct current generator, one is the worm shaft to active roll 14 transferring power; Its two for the velocity ratio of worm shaft be the axle of 12:1, fixing code-disc 5 thereafter is used for the revolution of measuring roller wheel drive motor 6.Drive active roll 14 rotations by running roller drive motors 6, realize the flexible cable folding and unfolding by the frictional force between flexible cable 1 and running roller, therefore, can realize the utility model up and down movement of direction in cleaning the plane by the coordination between the two running roller drive motors 6.
The drift angle testing agency of the utility model design comprises guiding slide bar 3, sliding rod rack 15, potentiometer 17, potentiometer support 16 and fairlead 2.Guiding slide bar 3 is installed on the utility model upper end by U-shaped 18, drift angle testing agency is risen support and guide effect, guarantees that drift angle testing agency is mobile in the horizontal direction.Sliding rod rack 15 is realized reliably being connected by bolt with potentiometer support 16, sliding rod rack 15 both sides have through hole, guiding slide bar 3 therefrom passes, sliding rod rack 15 can slide at guiding slide bar 3, be connected with potentiometer 17 and fairlead 2 on the potentiometer support 16, the effect of potentiometer 17 is that the corner with flexible cable in the space and level converts the receptible signal of single-chip microcomputer to
Flexible cable pilot hole 24 internal diameters of fairlead 2 are slightly larger than the diameter of flexible cable, link to each other with potentiometer 17 with the potentiometer connecting hole 22 of 90 ° of its one-tenth, and are fixing with trip bolt 21.Flexible cable 1 drives fairlead 2 by flexible cable pilot hole 24 and rotates, fairlead 2 rotates by the axle that potentiometer connecting hole 22 drives potentiometer 17, like this along with angle different between flexible cable 1 and the guiding slide bar 3, can detect the variable angle between flexible cable 1 and the guiding slide bar 3, then feed back to single-chip microcomputer, through the single-chip microcomputer computing, draw running speed and revolution that running roller drive motors 6 needs, thereby so that two running roller drive motors 6 can the coordinated movement of various economic factors, drive two active rolls, 14 folding and unfolding flexible cables 1, make the utility model to the target location easy motion, and arrive the target location along straight path accurately, reduced the motion distance, improved rapidity, accuracy.
The utility model course of work is as follows:
One end of two flexible cables 1 is separately fixed at the two ends, curtain wall top that need cleaning, flexible cable 1 other end is walked around from two groups of wheels of the present utility model respectively, flexible cable 1 first from the inboard of first groove of active roll 14 around the inboard to driven running roller 12 first grooves, again by the outside of driven running roller 12 first grooves around the outside to 14 second grooves of active roll, twine successively and form " 0 " word spiral; Screw 13 rotations produce thrust, realize the adsorption function of the utility model on vertical curtain wall, and generation brush 7 clean required normal pressure; The water that is stored in the water pot 9 is delivered to shower nozzle 11 through water spraying control valve 10, and by shower nozzle 11 ejection water smokes, two rotary brush 7 rotate under the driving of two brush motors 8, the cleaning of beginning glass wall.Simultaneously, Single-chip Controlling running roller drive motors 6 rotates, and drives two active rolls 14 and rotates, and at this moment, the utility model begins in the curtain wall plane mobile.By drift angle described in the utility model testing agency, detect between flexible cable 1 and the slide bar 3 angle, then feed back to single-chip microcomputer, single-chip microcomputer is by the calculating of program, draw running speed and revolution that running roller drive motors 6 needs, then by code-disc 5 record motor revolutions, feed back to single-chip microcomputer, realize the closed-loop control of motor, thereby so that two running roller drive motors 6 can coordinate to drive two wheels folding and unfolding flexible cables 1.When two running rollers were received simultaneously or put flexible cable 1, the utility model moved up or down, when two wheels, one receipts one are put flexible cable 1, and the utility model side-to-side movement.Whole cleaning process is by Single-chip Controlling, and employing bluetooth module realization wireless remote control, and operating personnel can be by the operation of remote controller Remote.
Claims (2)
1. glass curtain wall cleaning machine device people that two flexible cables drive, comprise two flexible cable driving mechanisms, drift angle testing agency, it is characterized in that: described pair of flexible cable driving mechanism, by two flexible cables (1), two groups of wheels and two running roller drive motors (6) and code-disc (5) form, every group of wheels are comprised of two grooved pulley type rollers with four grooves, comprise an active roll (14) and a driven running roller (12), active roll (14) is descending at upper driven running roller (12), two wheels left-right symmetry are installed between front end panel (20) and the rear bearing sheet (19), two active rolls (14) link to each other with two running roller drive motors (6) respectively, and running roller drive motors (6) is the direct current generator of band turbine and worm decelerator (4).One end of two flexible cables (1) of described two gentle lock driving mechanisms is separately fixed at two tops, curtain cleaning zone, be the suspension of falling the Eight characters, the other end of flexible cable (1) is walked around from two groups of wheels respectively, flexible cable (1) first from the inboard of first groove of active roll (14) around the inboard to first groove of driven running roller (12), again by the outside of first groove of driven running roller (12) around the outside to (14) second grooves of active roll, twine successively and form " 0 " word spiral.Two line shafts of reduction box output of direct current generator, one is the worm shaft to active roll (14) transferring power; Its two for the velocity ratio of worm shaft be the axle of 12:1, be used for fixedly code-disc (5).
2. drift angle according to claim 1 testing agency, it is characterized in that: described drift angle testing agency comprises guiding slide bar (3), sliding rod rack (15), potentiometer (17), potentiometer support (16) and fairlead (2), guiding slide bar (3) is installed on the robot upper end by U-shaped (18), sliding rod rack (15) is realized reliably being connected by bolt with potentiometer support (16), sliding rod rack (15) both sides have through hole, guiding slide bar (3) therefrom passes, be connected with potentiometer (17) and fairlead (2) on the potentiometer support (16), potentiometer (17) is connected 2 with fairlead) on potentiometer connecting hole (22) connect by marking closely screw (21), flexible cable (1) is passed fairlead by flexible cable pilot hole (24).
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN 201220255844 CN202681849U (en) | 2012-06-01 | 2012-06-01 | Double-wire driven glass curtain wall cleaning robot |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN 201220255844 CN202681849U (en) | 2012-06-01 | 2012-06-01 | Double-wire driven glass curtain wall cleaning robot |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CN202681849U true CN202681849U (en) | 2013-01-23 |
Family
ID=47537539
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN 201220255844 Withdrawn - After Issue CN202681849U (en) | 2012-06-01 | 2012-06-01 | Double-wire driven glass curtain wall cleaning robot |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN202681849U (en) |
Cited By (9)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN103445731A (en) * | 2012-06-01 | 2013-12-18 | 哈尔滨理工大学 | Double-flexible-cable-driven glass curtain wall cleaning robot |
| CN106354101A (en) * | 2016-11-30 | 2017-01-25 | 哈尔滨理工大学 | Derusting wall-climbing robot electrical control system |
| CN109018049A (en) * | 2018-06-22 | 2018-12-18 | 刘禄军 | A kind of wall surface walking device |
| CN110101332A (en) * | 2019-05-15 | 2019-08-09 | 江苏理工学院 | A kind of combined type window wiping robot system and clean method |
| CN111936024A (en) * | 2018-01-25 | 2020-11-13 | Lg电子株式会社 | Control method of robot cleaner |
| US11197595B2 (en) | 2017-08-07 | 2021-12-14 | Lg Electronics Inc. | Cleaner |
| US11478120B2 (en) | 2017-08-07 | 2022-10-25 | Lg Electronics Inc. | Cleaner |
| US11622661B2 (en) | 2017-08-07 | 2023-04-11 | Lg Electronics Inc. | Robot cleaner |
| US11744429B2 (en) | 2017-08-07 | 2023-09-05 | Lg Electronics Inc. | Cleaner |
-
2012
- 2012-06-01 CN CN 201220255844 patent/CN202681849U/en not_active Withdrawn - After Issue
Cited By (11)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN103445731A (en) * | 2012-06-01 | 2013-12-18 | 哈尔滨理工大学 | Double-flexible-cable-driven glass curtain wall cleaning robot |
| CN103445731B (en) * | 2012-06-01 | 2016-04-13 | 哈尔滨理工大学 | The glass curtain wall cleaning machine device people of two Wire driven robot |
| CN106354101A (en) * | 2016-11-30 | 2017-01-25 | 哈尔滨理工大学 | Derusting wall-climbing robot electrical control system |
| US11197595B2 (en) | 2017-08-07 | 2021-12-14 | Lg Electronics Inc. | Cleaner |
| US11478120B2 (en) | 2017-08-07 | 2022-10-25 | Lg Electronics Inc. | Cleaner |
| US11622661B2 (en) | 2017-08-07 | 2023-04-11 | Lg Electronics Inc. | Robot cleaner |
| US11744429B2 (en) | 2017-08-07 | 2023-09-05 | Lg Electronics Inc. | Cleaner |
| CN111936024A (en) * | 2018-01-25 | 2020-11-13 | Lg电子株式会社 | Control method of robot cleaner |
| US11439287B2 (en) | 2018-01-25 | 2022-09-13 | Lg Electronics Inc. | Controlling method of robot cleaner |
| CN109018049A (en) * | 2018-06-22 | 2018-12-18 | 刘禄军 | A kind of wall surface walking device |
| CN110101332A (en) * | 2019-05-15 | 2019-08-09 | 江苏理工学院 | A kind of combined type window wiping robot system and clean method |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| CN202681849U (en) | Double-wire driven glass curtain wall cleaning robot | |
| CN103445731B (en) | The glass curtain wall cleaning machine device people of two Wire driven robot | |
| CN105201184B (en) | Basket-hanging high-altitude wall sprayer | |
| CN106667364A (en) | Double-sucker glass curtain wall robot cleaner | |
| CN106419768A (en) | Wall surface cleaning machine | |
| CN102631172A (en) | Lifting telescopic corridor cleaning robot | |
| CN206770134U (en) | A kind of tower cleaning robot | |
| CN104825103A (en) | Glass curtain wall cleaning robot | |
| CN206655129U (en) | A kind of nacelle device of bridge construction | |
| CN107654076A (en) | A kind of foamed ceramics is built a wall manipulator | |
| CN109758025A (en) | A kind of basket-hanging glass curtain wall clean robot | |
| CN103792152B (en) | The special impact testing machine of a kind of chain adjustable slip-proof coating | |
| CN103913287A (en) | Tornado testing device for building wind engineering | |
| Deng et al. | Mechanism design and mechanical analysis of multi-suction sliding cleaning robot used in glass curtain wall | |
| CN207078225U (en) | A kind of Gao Fang robots for being exclusively used in climbing thin bar part | |
| CN206766177U (en) | A kind of tower permanent magnetism crawler belt climbing robot | |
| CN208310129U (en) | High building exterior wall automatic spraying machine | |
| CN102170097A (en) | Two-arm-regulating gravity type inspection robot for high-voltage transmission lines | |
| CN206874021U (en) | Planar movable three-dimensional garage transverse-moving trolley | |
| CN210277039U (en) | Hanging basket type glass cleaning device | |
| CN205685324U (en) | A kind of gantry truss-like indoor substation crusing robot | |
| CN102070084B (en) | Rain-proof device for rectilinearly movable exit of wire rope | |
| CN201701162U (en) | High-rise building wall surface cleaning robot moving mechanism | |
| CN209066348U (en) | A kind of environmental protection road guardrail cleaning device | |
| CN203354456U (en) | Slide type arc rotary window cleaning machine |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| C14 | Grant of patent or utility model | ||
| GR01 | Patent grant | ||
| AV01 | Patent right actively abandoned |
Granted publication date: 20130123 Effective date of abandoning: 20160413 |
|
| C25 | Abandonment of patent right or utility model to avoid double patenting |