Abstract:
A robot including a manipulating arm affixed to a hub by axial tapping so that the hub engages a threaded part of a driving shaft. The hub and driving shaft are coupled with output shaft of motor controlled by command and control unit. A braking gear linked to the hub and the driving shaft to ensure that the hub is locked with respect to the driving shaft as long as the moment of resistance exerted on the hub is less than a predetermined value. The gear enables the rotation of either the hub or shaft with respect to the other when the moment is equal to a set value. A mechanism for rotation locking, capable of being activated by the command and control unit, is further provided to lock rotation of the hub and the arm. When the mechanism for rotation locking is activated to block the hub and or the arm, then the arm is capable of being vertically translated by activating the motor.

Description:
BACKGROUND OF THE PRESENT INVENTION 
     1. Field of the Invention 
     The present invention relates to a conveyor robot namely for the manipulation and transport of an object along a specified path. 
     2. Description of Related Art 
     Robots are already known from the prior art for the manipulation of objects. These robots contain a manipulator arm that is mobile along three axes in space. Generally, this arm is motorized by three motor structures constructed based on a kinematic configuration called an open chain. The first of these structures ensures the displacement of the manipulation arm along a first horizontal axis, the second structure along a second horizontal axis normal to the first one, and the third along a vertical axis. The main disadvantages of these structures rest in their complexity and in their high cost. 
     BRIEF SUMMARY OF THE INVENTION 
     The purpose of the invention presented here is to compensate for the disadvantages mentioned by implementing a, manipulator robot having an excellent efficiency while having a simplified design and a low cost. 
     For this purpose, the manipulator robot according to the present invention contains a manipulator arm that can be moved by a first motor piloted by a command and control unit, whereby the first motor and the unit are installed in a frame mounted on the running gears. This robot is characterized essentially in that: 
     the first motor is equipped with a rotary output shaft on which a mechanical torque is applied, 
     the manipulator arm is affixed by one of its ends to a hub provided with an axial internal screw threading in which the threaded part of a drive shaft, which is coupled to the rotary output shaft of the first motor, is engaged by being screwed in, 
     it is provided with a brake gear that is connected to the hub and to the drive shaft, this brake gear ensuring the immobilization of the hub relative to the drive shaft while the resistance torque exerted on the arm or on the hub is less than a predetermined value, and this gear allowing the rotation of the hub relative to the drive shaft while this resistance torque is equal to this value; and 
     it is provided with a mechanism for locking in rotation activated by the command and control unit in order to lock the rotation of the hub and the arm, this mechanism while it is activated acting to lock on the hub and/or on the arm, the aforementioned arm being thus able to be moved in translation relative to the chassis by activation of the first motor. 
     Thus, this device makes it possible to avoid the use of a third motor for the displacement of the arm in translation. The first motor ensures the displacement of the arm in rotation while the brake gear is deactivated and its drive in translation when this gear is activated. 
     According to another characteristic of the invention: 
     the axial internal threading made in the hub is extended axially by a smooth bore, 
     the drive shaft, in the axial extension of its threaded part, is equipped with a smooth bearing surface engaged in the smooth bore of the hub; and 
     the brake gear is made by a stopper of a synthetic material engaged in a radial hole made in the hub and opening into the axial bore of it, this stopper being held under pressure against the smooth bearing surface of the drive shaft. 
     The invention presented here also has the purpose of a system that is essentially characterized in that it is equipped with at least one robot according to the invention. 
     According to another characteristic of the invention, the system consists of at least one distribution station for solid and/or liquid material by dosed quantities as well as at least one processing station, these different stations being arranged one after the other relative to at least one track on which the robot maneuvers. 
    
    
     BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWINGS 
     Other advantages and characteristics of the invention appear in reading the description of a preferred embodiment form, and referring to the attached drawings. 
     FIG. 1 is a sectional view of the profile of the robot according to the invention, 
     FIG. 2 is a sectional view of the side of the robot associated with a system according to the invention, 
     FIG. 3 is a detailed schematic view of the robot according to the invention, 
     FIG. 4 is a top view of the robot according to the invention, 
     FIG. 5 is a longitudinal sectional view of the cover distributor according to the invention, 
     FIG. 6 is a top view of the cover distributor according to the invention. 
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     As shown, the manipulator robot  1  according to the invention consists of a chassis  2  mounted on the running gears  3 ,  4  in order to maneuver on a track. The chassis is made of a three-dimensional structure that defines a parallelopiped volume that receives a protection cover forming the upper horizontal wall and the lateral vertical walls in the front, rear, right and left of the robot. 
     The robot  1  consists of a horizontal manipulator arm  5  that can be moved in rotation in a horizontal plane by a first electric motor  6 , piloted by a command and control unit  7  installed affixed to the chassis, in the space that is defined by the cover. In this space, at least one electric battery can be installed, which ensures the supply of electric power to the first electric motor, the command and control unit  7  and more generally to any of the electric components mounted on the robot. The electric supply can also be outside of the robot, in which case a known type of electric line is provided in order to electrically connect this supply to the electric components of the robot. The unit  7  commands and controls notably the movements of the arm  5 . 
     The electric motor  6  is of the type consisting of a rotary output shaft  6   a  on which a driving torque is applied. The output shaft of this motor can be driven in rotation in one direction or the other according to the direction of the electric voltage applied to the supply terminals. 
     The supply of electric power and the direction of the voltage applied to the input terminals of the motor  6  are two parameters generated by the command and control unit  7 . 
     The electric motor  6  is affixed by its casing to the lower side of the horizontal upper wall. This wall, in axial alignment with the output shaft of the electric motor  6 , is provided with a cylindrical hole going through it, in which the tip of the coupling  8   a  of the vertical drive shaft  8  of the arm  5  engages. This tip of the coupling  8   a  is affixed by connecting to the output shaft  6   a  of the electric motor  6 . 
     The drive shaft  8  consists of a threaded part and a smooth part formed in the extension of the threaded part. Onto this drive shaft  8 , a hub  9  is united to make a solid piece to receive the manipulator arm  5  by being affixed to it. This hub has a cylindrical form and contains at a lower end a seating  9   a  having a circular contour. 
     The hub  9  is provided with an axial internal threading in which the threaded part of the drive shaft  8  engages by being screwed in. In the axial extension of the threading, the hub  9  consists of a smooth bore, opening into the upper side of the hub. In this smooth bore, the smooth bearing surface of the drive shaft engages. 
     Onto the hub  9  and the drive shaft  8 , a brake gear is linked, ensuring the immobilization of one relative to the other when the resistant torque exerted on the hub  9  is less than a predetermined value, and allowing the rotation of one relative to the other when the resistant torque is equal to this value. In addition, a mechanism is provided for locking in rotation  10  activated by the command and control unit  7  in order to act on the hub  9  and to block the rotation of the hub and thus of the arm  5 . This mechanism  10 , when it is activated, ensures the locking of the arm  5  in rotation relative to the chassis. This arm  5  can thus be moved in translation relative to the chassis by the activation of the first motor  6 . While this mechanism is deactivated and thus disengaged from the hub  9 , the arm  5  can be driven in rotation by the first motor  6 . 
     According to the preferred embodiment form, the brake gear is housed in a radial hole  11  made in the hub and opening into the axial bore of it. This brake gear is made of a cylindrical stopper  12 , of a synthetic material kept at a pressure against the smooth bearing surface of the drive shaft. According to the preferred embodiment form, the stopper is kept against this smooth bearing surface by an axial thrust exerted by a screw  13  engaged by screwing into an internal threading made in the radial hole  11 . 
     Thus, it is understandable that the transmission of the motor torque and of the rotation movement between the drive shaft and the hub is done by the intermediary of the brake gear. Also, it is understandable that this rotation movement is no longer transmitted if the resistant torque exerted on the hub reaches a certain value that is directly dependent on the forces of pressure between the stopper  12  and the smooth bearing surface of the drive shaft  8 . It is thus possible to adjust this value in a precise manner as a locking torque of the screw  13 . When the resistant torque reaches this value, the transmission of rotation movement to the hub no longer occurs. On the other hand, as the drive shaft is always driven in rotation by the motor  6 , this produces in the rotational direction of the output shaft of the motor, a movement of unscrewing or screwing the threaded part of the shaft  8  in the internal threading of the hub  5 , either towards the top (unscrewing movement), or towards the bottom (screwing movement). In this manner, the arm  5  can be elevated relative to the chassis and then lowered. 
     Advantageously, the synthetic material used for the stopper  12  is of the type of those marketed under the name TEFLON(™). Other materials can be used having equivalent mechanical properties. Due to the mechanical characteristics of the material used, the stopper  12  ensures effective braking of the screw  13  so much so that the intensity of the forces of pressure of the stopper against the smooth bearing surface of the shaft remains constant over time or at least varies very little. 
     The linear course of the arm is controlled by the control and command unit  7  that controls, for this purpose, the number of turns made by the output shaft of the motor  6  due to the information supplied by an incremental counter coupled to this shaft. However, in order to compensate for any risks of malfunction of the control and command unit  7 , the drive shaft  8 , outside of the hub, at the free end, consists of an abutment  14  forming a shoulder. At the lower position of the arm  5  and thus of the hub  9 , the upper side of this hub  9  is offset from the abutment. This abutment is thus fitted to limit the linear course of the arm  5  and most particularly its ascending movement. 
     According to the preferred embodiment form, the mechanism  10  for locking in rotation is made of a locking pin  15 , preferably vertical, mounted in a manner so that it is mobile in translation in a guide bearing  16  united to make a solid piece with the chassis, and by a motor instrument  17  for activating the pin  15 , controlled by the control and command unit  7 . More specifically, the guide bearing  16  is affixed in an opening made in the upper wall of the cover. The motor instrument  17  is equipped with an output shaft  18  for linear displacement which is united to, make a solid piece with the locking pin  15 . This locking pin, when the motor instrument  17  is activated, comes to engage a hole  22  made in the hub  9  in order to form a connection by being an obstacle and to block rotation. More precisely, the hole  22  is made in the seating  9   a  of the hub  9 . 
     The hole  22  forms the only angular position of the arm in which it can be moved in translation. It can prove to be useful to be able to move the arm in translation while it occupies another angular position. For this reason, the hub  9  can be provided with several holes  22  whose displacement is selected as a function of the requirements. 
     Advantageously, the motor instrument  17  is made of a solenoid. 
     In order to locate the position of the locking pin  15 , two capacitive sensors are provided (not shown) positioned respectively relative to the end positions of the pin  15  along its course and connected electrically to the command and control unit. These sensors are fitted to transmit information representing the lowered or elevated position of the locking pin  15  and thus information relative to the locking in rotation of the hub  9  or the release of it. 
     In order to simplify the assembly of the solenoid  17  as well as the pin  15  while avoiding any specific positioning of one relative to the other, the output shaft  18  of the solenoid  17  and the locking pin  15  are united relative to each other by a semi-rigid connection. According to the preferred embodiment form, the shaft  18  and the locking pin  15  are axially shifted forward one relative to the other and the semi-rigid connection is made on the one hand, in the form of a fork formed in a disc  19  affixed in the lower part of the locking pin  15  and of a circular groove  20  hollowed in a cylindrical joining piece  21  affixed to the output shaft  18 . The shape of the fork is engaged with low play in the groove  20 . Such a device is favorable for avoiding any jamming. 
     The hub  9  is equipped with at least one initialization reference mark  23  facing the trajectory of which a detector is arranged that is electrically connected to a command and control unit, this detector supplying a signal for detection of the reference mark  23 , this signal being used by the control and command unit  7  in order to mark the original angular position of the arm. According to the preferred embodiment form, the initialization reference mark  23  is made of a excessive thickness peripheral to the hub, limited by two diametrically opposed radial end sides. This excessive thickness is affixed by a screw to the seating  9   a  of the hub  9 . 
     According to the preferred embodiment form, the detector is of the photoelectric type. Preferably, the detector is installed in the space that is defined by the structure of the chassis. In order to detect the passage of the reference mark  23 , an optical fiber is then used, which is engaged at one of its ends in a hole that is made going through in the upper wall facing the path of the reference mark  23  and positioned by its other end relative to the photoelectric cell of the detector. 
     Advantageously, mechanisms are provided for detection of the locking of the arm in rotation, which are activated when the mechanism for locking in rotation is deactivated. These mechanisms are essentially made of the incremental coder coupled to the motor  6  and by the control and command unit  7 , which compares at each instant the real angular position of the arm to the theoretical position of it, this position being defined in a manner by software programming. In the case where the distance between the two positions is greater than a prespecified value, the command and control unit  7  deactivates the motor  6 . 
     One of the running gears is coupled to a second motor  24  controlled by the command and control unit  7 . According to the preferred embodiment form, three running gears are provided, of which the first and the second  3  are placed on one side of the chassis and the third  4  on the other. The third running gear is coupled to the output shaft of the second motor instrument  24 . 
     An incremental coder is coupled to the output shaft of the second motor instrument  24 . This incremental coder is connected electrically to the control and command unit  7  and transmits information regarding the absolute position of the robot. As for the arm, the central unit continuously compares the real position of the robot to the theoretical position and cuts the supply to the motor if the distance of the position is greater than a predetermined value. 
     According to a first embodiment form, the third running gear  4  is made of a catch gear and is designed to act together with a rack  25  made on a track  26  on which the robot is designed to maneuver. This track can be in a straight line or curved or it can even follow any type of profile desired. 
     The two first running gears  3  can be made up of rollers for a triangular groove and can be designed to be engaged on a guide rail  27  having a triangular cross-section formed on the track  26 . 
     According to a second embodiment form, the running tread of the third running gear is smooth. 
     According to a particularly advantageous form of the invention, the second motor instrument  24  is united to make a solid piece with a plate mounted in rotation along a vertical axis, the plate along this axis being coupled to the vertical output shaft of a third motor instrument controlled and commanded by the command and control unit. This device controls the direction of the third running gear. Thus, in activating the second and third motor instruments, it is possible to command and control the maneuvering of the robot, not only on the guide rails which determine an immovable route, but also on a horizontal plane, along any variable route, controlled and commanded by Hertzian waves or ultrasonic waves. For this purpose the robot will be equipped with a receptor for Hertzian waves or a receptor for ultrasonic waves connected electrically to the command and control unit  7  and provided with a station for telecommunications arranged at a distance, this station being provided with a transmitter of Hertzian waves or a transmitter of ultrasonic waves designed to be controlled by an administrator and/or a computer, the latter ensuring the guidance of the robot by telecommunications in the space which it must maneuver, this space can be a place consisting of one or more levels where the topography and the placement of furniture and other objects that equip it are known and stored in the memory register. The telecommunications station will be equipped with a screen by which the administrator can see the map of the place and see the position of the robot in the place for the purpose of piloting it. In order to ensure the locating of its position, the robot will be equipped with a system for echo-location connected electrically to the command and control unit  7  and with a transmitter for Hertzian waves and ultrasonic waves in order to indicate its position to the station, this transmitter being also connected electronically to the command and control unit  7 . In addition, the telecommunications station will be equipped with a receptor for Hertzian waves and ultrasonic waves in order to receive the position of the robot. This robot will be equipped with detectors for obstacles judiciously arranged in periphery, consisting, for example, of ultrasonic detectors by radar, etc. These detectors are connected electrically to the command and control unit  7 . 
     As soon as the robot encounters an object on its route, the command and control unit  7  commands the stop of the second motor  24  and activates the system for echo-localization and transmits to the telecommunications station a message that is representative of the stop of the robot and its position. The administrator and/or the computer can then define another route. 
     It is noted that the transmission mode is not limited to the transmission by Hertzian waves or ultrasonic waves, any other type of waves can be used, for example, infrared waves. 
     The arm  5  at the free end can be equipped with a prehensile squeezing device, a tool, a read and/or write head, a fork lift, a measuring instrument, a cleaning tool or even as can be seen in FIG. 2, with two opposed indentations  28  by the border of each of which it is designed to engage under the prehensile flange of an object to be grasped and transported. 
     The robot as described is designed to equip a system for distribution of solid and/or liquid and/or pasteous materials, this system possibly carrying out the treatment of these materials. For this purpose, the system consists of at least one station for the distribution of solid and/or liquid and/or pasteous materials according to dosed quantities and possibly one or more station(s) for treatment. These different stations are arranged one after the other along the track  26  that consists, as previously mentioned, of on the one hand, the rack  25  and the other hand, the guide rail  27 . The rack and the guide rail are parallel to each other, and the running gears  3 ,  4  of the robot are designed to act together with the rack and the guide rail. 
     The materials sent by the different stations of the system are collected in the cylindrical containers  29  each containing a prehensile flange  30  along the lip. Each container is transported from station to station by the manipulator robot and after mixing the different ingredients according to a preset program, first, if need be, towards an agitator station then towards an evacuation station. 
     In order to prevent the evaporation of liquid products, or more generally the volatile ingredients of distributed materials, each container  29  is able to receive a cover  31 . Thus, the system is fitted with a distributor  32  of covers  31 . This distributor consists of a chassis supporting a cover magazine in which the covers are stacked in a pile. In addition, this distributor  32  consists of a take-off and distribution mechanism for taking off the lower cover of the stack and distributing it to the container  29  positioned previously under the pile by the robot. 
     Each cover  29  contains a truncated-cone shaped stopper made by a swaging bordered by a prehensile flange, the covers in the magazine being stacked one into the other by their stopper shape. The flanges of the covers, in the pile that is formed, are spaced regularly from each other. 
     The mechanism for taking off the cover is made of at least three vertical shafts  33  spaced apart from each other and defining a volume for stacking in which the cover pile  29  is formed. The shafts  33  are mounted rotatably with the upper bearings united to make a solid piece with an upper horizontal plate  35  and in the lower bearings affixed to a lower horizontal plate  37 . This plate  37  is provided with a circular hole  38  going through the covers. Each shaft  33 , below the lower plate  37 , is provided with a threaded joining piece  39  in the thread of which, the prehensile flange of the cover  29  is engaged, the shafts being driven simultaneously in rotation by a motor assembly  40  in the direction of the distribution of the cover. 
     The pitch of the thread of each threaded joining piece  39  is equal to or is a multiple of the interval between two consecutive flanges. 
     The motor assembly  40  is made of an electric motor  41  affixed by its housing to the upper plate  35  that contains on the output shaft a drive pinion  42  acting together enmeshed with a second pinion  43  affixed on one of the shafts, this second pinion being enmeshed with a toothed transmission gear  44 , with which two other pinions  43  are acting together respectively affixed on the two other shafts  33 . 
     The different motors of the robot and the motor  41  of the distributor of the covers are advantageously of the same type which allows a sensible reduction in the cost of the assembly. 
     In addition, these motors are supplied with electric power based on a voltage that is well below their normal voltage of use which allows them to increase both the reliability and the safety of the assembly. 
     Needless to say, the invention presented here can have any arrangements and variations in the domain of equivalent techniques without leaving the score of the present patent.