Patent Publication Number: US-5427564-A

Title: Controlled surface treating work device

Description:
BACKGROUND OF THE INVENTION 
     1. Field of Invention 
     Relates to the automated application of a robot carried work device embodying speed and pressure control of a work wheel in treating the surface of a work piece. 
     2. Description of the Prior Art 
     The effort of finishing material surfaces such as of metal, glass and wood and the like has been traditionally the result of skilled hand labor. The skill has been applied not only in direct hand labor as in the use of hand tools but also in the hand control of mechanized tools. A uniformity of result has been difficult to achieve. 
     There were adverse effects to hand labor and the hand manipulation of tools resulting from the repetitive action of the effort which required the worker to operate in a dust laden atmosphere potentially damaging to the eyes and respiratory system of the worker. Also the repetitive action resulted in many workers developing and becoming afflicted with the Carpal Tunnel Syndrome which is a very undesirable affliction. 
     SUMMARY OF THE INVENTION 
     It is a principal object herein to make the work effort involved more productive and to provide a more desirable environment for the workers involved. 
     It is another object herein to make automatic and self regulating the work effort involved in the operation of a surface treatment device. 
     It is a further object herein to provide uniform results in the work effort output by the automatic self regulation of the work effort in treating the surface of a work piece. 
     It is a further object herein to have a predetermined control of and a regulated work effort in the application of the speed and pressure of a work wheel in its engagement with the surface of a work piece. 
     It is also an object herein to have the work device mounted as upon a robotic arm for a self controlled automated application of work effort. 
     These and other objects and advantages of the invention will be set forth in the following description made in connection with the accompanying drawings in which like reference characters refer to similar parts throughout the several views. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     FIG. 1 is a top plan view with a portion thereof broken away and a portion in dotted line showing an alternate position; 
     FIG. 2 is a view similar to FIG. 1 in side elevation; 
     FIG. 3 is a view in horizontal section taken on line 3--3 of FIG. 4 as indicated; 
     FIG. 4 is a longitudinal vertical section with a portion thereof broken away; 
     FIG. 5 is a view in vertical section taken on line 5--5 of FIG. 2 as indicated; and 
     FIG. 6 is a broken view in side elevation showing the device herein mounted onto an arm extension as of a robot. 
    
    
     DESCRIPTION OF A PREFERRED EMBODIMENT 
     As a preliminary explanation in connection with the device of the invention herein, in the embodiment here presented, this device is particularly adapted to be mounted or based upon a robotic arm and the work pieces are brought to it for engagement with it by another automated work piece handling device such as another robotic arm which however does not form any part of the invention herein. 
     A work piece is brought into engagement with the device of the invention herein for deburring, sanding and/or polishing to produce a finished surface. A work piece is indicated at A and its robotic holding arm is indicated at B as in FIGS. 1 and 2. 
     Referring further now to FIGS. 1 and 2, the device of the invention herein is indicated generally by the reference numeral 10 and it is generally characterized as a surface treating device. 
     As shown, said device 10 has a bottom wall or base 11 which is generally rectangular in plan. Said base has ends 12 and 13 and sides 14 and 15, upstanding from said ends are end walls 17 and 18 which are arcuate or semi-circular in form as shown in FIG. 5. 
     Referring to FIGS. 3 and 4, upstanding from said base are spaced transverse support members 20 and 21, which are equally spaced from said end walls. 
     Extending through said support members adjacent the ends thereof and extending to said end walls of said base are slide rods 23 and 24, said slide rods being in parallel spaced relation. 
     Mounted respectively onto said slide rods between said support members and said end walls are slide members 25 and 26. Said slide members are indicated as being rectangular in plan and are vertically disposed. Said slide members are mounted onto said slide rods on low friction bearings 27 whereby there results unrestricted free sliding movement between said slide members and said rods. 
     Positioned between said support members (FIG. 3) are a pair of reversely disposed pneumatic cylinders or tanks 28 and 29 respectively having extending pistons 28a and 29a. 
     Leading into said pneumatic cylinders 28 and 29 are air lines 30 and 31 (FIGS. 4 and 5), said air lines being in communication with a source of pressurized air through a computer regulated air pressure control member 32, said computer is not herein shown. 
     Said cylinder 28 has a piston 28a in connective engagement with the slide member 25 and said cylinder 29 has its piston 29a in connective engagement with the slide member 26. 
     Mounted onto said slide members 25 and 26 is a tool supporting member 35 (FIGS. 4 and 5) having a base plate 36 mounted directly onto said slide members and having a supporting portion 37a underlying said tool support member 35. 
     Mounted onto said tool support member 35 is a powered tool indicated generally by the reference 40, said tool comprising a body member 50 secured to said mounting member 35 by conventional brackets or clamps 51. Extending from said body member 50 is a power line 52 which will be extended -to a convenient power source. Said tool member may be self-powered. 
     With particular reference to FIGS. 1 and 2, said tool body member 50 carries a grinding or work wheel 42 mounted upon a vertical drive shaft 41 and having a peripheral or surface portion 43 adapted to debut, grind or sand a surface or be adapted to put a polished finish onto a surface. Thus the axis of said work wheel is at right angles to the plane of said tool supporting plate 35 and moves longitudinally therewith as viewed in FIGS. 1 and 2 and its axis is also right angles to the movement of the slide members 25 and 26. 
     An essential novel element of this device is said air pressure control unit 32 which is adapted and caused to have said pistons of said cylinders 28 and 29 exert an equal force to have a constant pressure apply on said work wheel to have said work wheel apply a constant uniform pressure on an engaged work piece in treating the surface of such work piece. The cylinders and their respective pistons are positioned to move said slide members, the tool support member mounted thereon and the tool mounted work wheel a predetermined distance in the direction of the axis of said pistons which is at right angles to the axis of the work wheel. 
     With the direction of the movement of said tool supporting member being at right angles to the axis of the work wheel and with the edge or peripheral surface of the work wheel being engaged with said work piece A, it is seen that the pistons of said cylinders 28 and 29 can be preset to cause the tool supporting member to move a specified distance and be thus positioned. 
     The constant use of the work wheel will cause its edge or peripheral surface to wear and eventually reduce the diameter of the work wheel. As the work wheel diameter is reduced, the peripheral speed of the work wheel will reduce. However for a certain degree wear, any difference in the finish of the work piece will be imperceptible. Thus a leeway is built into the work wheel. At the point at which the leeway allowance is used up, as will be described, a conventional signal not here shown will alert the operator to reindex or replace the work wheel. 
     In addition to a control on the pressure applied by the work wheel onto an engaged work piece, there is also a control maintained on the peripheral speed of the work wheel. In the present embodiment, for this purpose, a linear potentiometer 45 is used as indicated in FIG. 3. Said potentiometer has a rod or shaft extension 45a which serves as a sensing shaft and the same is secured to one of the sliding members, which in the present instance is member 25, being secured thereto by a bracket 46. The potentiometer will be adjusted to provide for the predetermined rate of speed of the work wheel based on the extent of movement of said slide member to which it is attached. 
     As the periphery of the work wheel wears from use up to its leeway allowance, with each increment of additional increased extension of its sensing shaft in moving with said sliding member, the potentiometer immediately accelerates the motor of the powered tool by providing a proportional voltage signal for the powered tool to maintain the original peripheral speed of the work wheel. This is a conventional arrangement not specifically shown here. 
     With the inclusion of the two pneumatic cylinders 28 and 29, their respective pistons 28a and 29a exert a precise balancing or counterbalancing pressure between the powered tool and its work wheel to offset the influence of the unbalance of weight of the powered tool 40 as to its work wheel 42 as mounted upon the support member 35 whereby with the powered tool and its work wheel being in balance with each other and thus kept in balance, in effect, it is as if the powered tool and its work wheel are weightless as to each other. Thus a very precise pressure may be applied in the engagement of a work piece by the work wheel, the pressure being adapted exactly for the result it is desired to achieve. 
     Any disturbance in the balance established is sensed by the pressure control member 32 and immediate adjustment is made through said cylinders and its pistons acting on said sliding members to maintain the desired balance of the mounted or supported tool 40 and its work wheel. 
     Referring to FIG. 6, the entire device 10 upon its mounting plate 9 is shown carried by a robot operated arm extension 8, the robot being no part of the invention herein is not further shown. 
     It will of course be understood that various changes may be made in the form, details, arrangement and proportions of the device of the invention without departing from the scope of the invention, which, generally stated, consists in an apparatus capable of carrying out the objects above set forth, such as disclosed and defined in the claims.