A DEVICE FOR GUIDING A TOOL ALONG A CURVE

Abstract: In order to guide a tool (17) along a curve (24), a curve follower is connected to the tool, said curve follower including two rotatable means (43, 44), one (44) of which is driven and the other (43) freely rotatable. The two rotatable means (43, 44) are adapted to contact, preferably resiliently, a guide curve (5) from either side. The guide curve is an extended strip of flexible material.

Description: A DEVICE FOR GUIDING A TOOL ALONG A CURVE The present invention concerns a device for guiding a tool along a curve, said device comprising a holder for the tool being movable in one plane and -being so connected to a curve follower, which is adapted to follow a predetermined guide curve in the same or another plane, that the holder and the tool follow a path corresponding -to the path of the curve follower. A tool of the kind here intended can be e.g. adapted to discharge sea-ling compound, or, be a cutting torch, a corresponding device then serving for repeatedly distributing sealing compound over the sealing surfaces of identical objects, or, cutting identical sheet metalpieces. In -a known device of the kind initially stated, which serves to apply a string of silicone sealing compound on joint surfaces, the curve follower is a roller, which is freely rotatably journall,ed in one end of " a horizontal ^ arm. The roller engages from underneath into and runs along a slot milled through a plate * Since this slot describes a closed pattern the central part of the plate must be suspended, which is done in the support for the object to be charged with sealing compound. The tool, an extrusion device for the sealing compound, is mounted in the end of a manually operable arm, which horizontally is rigidly connected to the arm just mentioned. The two arms are commonly pivotedly connected to a third arm, such that the roller and the extrusion device are freely movable in one horizontal plane each . Apart from the evident drawback that a closed guide slot requires suspension of the central part of the plate, i.e. , one defining curve ' of the guide slot, a milled guide slot requires expensive machines and time consuming work to be accomplished. Further, the manual operation of the tool involves - even with the most skilful operator - that the movement along the curve hardly can take place with a constant speed, which in turn results in that the string of sealing compound receives a varying thickness if it is extruded with a continuous flow. This in turn may have devastating consequences, particularly if too much sealing compound is extruded, since sealing compound forced outside sealing surfaces may come loose and stick in e.g. the cooling channels of a combustion engmge . The present invention has as its object to provide a device of the kind .initially stated, which allows the utilization of- particularly cheap, simple and easily shapable guide curves, along which the curve follower is movable in an even speed. This object has been achieved in that the invention has received the characteristics stated'in the following claims. One example embodying the invention will be described below, reference being ma.de to the accompanying drawings, wherein fig. 1 is a partially broken up perspective view showing a device according to the invention adapted to apply a string of sealing compound along a closed path, fig. 2 shows at a larger scale and likewise in a perspective view a curve follower and a portion of a guide curve according to the invention, and fig. 3 shows a section taken along the line 111—111 of fig. 2 through the curve follower as well as the guide curve. Above a plane, rectangular base 1 is mounted, by means of columns 2 , a likewise rectangular working plane 3. Upon the base 1 rests a plane plate 4 , which by means not shown s attachable to the base. On the plate 4 is mounted a guide curve 5, which will be further described below. Between the base 1 and the working plane 3 is arranged a coordinate table of a known kind comprising a cylindrical bar 6, which is parallel to and located close to an edge of the base 1. An L-bar 7, against which advantageously abuts one edge of the preferably rectangular plate 4, is mounted parallel to the bar 6at the opposite edge of the base 1. By means of ball bushings 9 a first carriage 8 is movable along the bar 6. Also the carriage 8 comprises a cylindrical bar 10 and an L-bar 11 parallel thereto, both- being perpendicular to the bar 6. By means of rolls not shown, e.g. in the shape of Toller bearings, the carriage 8 is supported on the L-bar 7. ' By means of .ball bushings 13 a second carriage 12 is movable along the bar 10 and by means of rolls 14 it rests on the L-bar 11. - By means of a vertical bar 15 and a horizontal, verti¬ cally adjustable arm 16 the carriage 12 carries above the 'working plane 3 an extrusion apparatus 17 comprising a pressure operated tube 18 for sealing compound and a likewise, by means of a cylinder 19, pressure operated valve' 20, which is mounted between the tube 18 and a nozzle 21. By means of the arrangement now described the nozzle 21 is movable in a horizontal plane, which by varying vertical adjustment .of the arm 16 can vary between the working ' plane 3 and an arbitrary hight thereabove. In the example shown, an object 22, e.g. a valve cap for a combustion engine, is indicated by dash-dotted lines lying on the working plane 3. The nozzle 21 is adjusted to apply a str-ing 23 of sealing compound on the sealing surface 24 of the object 22, which is located in a plane above the working plane 3. In order to apply a string of sealing compound along a predetermined curve, the guide curve 5 mounted on the plate 4 is shaped in an exactly corresponding manner. The guide curve comprises a flexible strip of e.g. sheet metal, which is adapted to be attached protruding from a base. In the example shown (figs. 2 and 3 lugs 25, 26 are cut in one edge of the strip and are bent at a right angle to either sides of the main portion of the strip, so that the strip can stand on the lugs and easily be attached to a base, e.g. the plate 4, which advantageously can be made of wood or a material based on wood by means of nailing or screwing. Bending of the strip to the curve shape desired can very easily take place by hand-. One of the surfaces.of the strip is advantageously provided with a glued or vulcanized band 27 of friction- increasing- material, such as rubber. The " cam follower according to the invention, which is particularly shown in figs. 2 and 3, includes a cylind— rical housing 28,.wh*ich is attached to a part of" the carriage 12 by means of a welded attachment flange 29. Centrally through the housing 28 extends a shaft 30, which is journalled • in ball bearings 31 and 32 in bo.th end ' s of the housing. At the upper end of the shaft is unrotatably mounted a wheel 33, which, by means o " f a drive belt " 34, is drivingly connected to an ' electric motor 35 (fig_. 1). _ Suitably the drive belt 34 is a toothed belt, the wheel 33 and the- drive wheel of the motor 35 then being provided with corresponding teeth. On the lower end of the shaft 30 extending from the housing 28 is pressed the inner race of a ball bearing 36, the outer race of which by means of a clamping joint 37 carries a laterally extending first arm 38. At the free end of the arm 38 is rotatably journalled a vertical shaft 39, which in turn carries a second arm 40, which in its free end is provided with a depending stationary stud 41. On this stud is mounted the inner race of a roller bearing 42. The arm 40 has such length that the .outer race 43 of bearing 42 can touch the lower end 44 of shaft 30. A spring 45 mounted -between the arms 38 and 40 presses the outer race 43 towards the shaft end 44. The outer race 43, thus, serves ascounter press roll for the shaft end 44. « The. cam follower now described is adapted to grip, with the outer race 43 and the ' shaft end 44, the vertical portion of the guide curve 5 described above. For that purpose, the shaft end 44 is advantageously ■ nurled for cooperation with the band 27 of the guide curve 5. Due to the fact that the arms 38 and 40, which carry the counter press roll 43, are freely rotatable relative t ' o • the shaft 30, and, due to the fact that the roller 43 s constantly urged towards the shaft end.44, it is achieved that the centers of the roll 43 and the shaft end 44 always will tend to be located on one and the same normal to the guide curve 5, or, in other words, that the counter • press roll 43 always tends to be situated opposite to the driven and driving shaft end 44, i.e. , where it with the best function pulls the shaft end 44 to operative guide and drive engagement with the guide curve- 5. By the invention has been achieved a very simple,- cheap and extremely well functioning device. It is realized that many . modifications can be made within ' the scope, of the inventive • concept. Thus, the drive motor may e.g. be mounted directly on the shaft 30. Likewise, the swingability of the counter press roll may be different, e.g. about a horizontal axis. Of course, the coordinate table may be replaced by another arrangement, e.g. similar to the one initially described having inter-pivoted arms. For controlling the motor 35 and the pressure feeding of the extrusion apparatus 17 there is a control panel 46 having a.o. a starting button 47. A micro switch 48, which is mounted close to the guide curve 5, stops the motor after a completed round about the guide curve. In certain appplications of the invention, e.g. where the tool is a cutting torch, it may be suitable that the tool and the guide curve are located in substantially the same plane with the tool laterally displaced outside the guide curve. .' f

Claims: CLAIMS 1. ' A device for guiding a tool (17) along a curve (24), said device comprising a holder (16) for the tool being movable in one plane and being so connected to a curve follower, which is adapted to follow a predetermined guide curve (5) i.n the same or another plane, that the holder (16) and the tool (17) follow a path corresponding to the path of the curve follower, c h a r a c t e r i z e d i n that the curve follower includes two rotatable means (43,44), one (44) of which is driven and the other (43) freely rotatable, said two rotatable 'mean ' s being adapted to contact a guide curve (5) from either side. 2. A device according to claim 1, c h a r a c t e r ¬ i z e d i n that 'the driven -rotatable means (30,44) is journa-lled in a part (28,29) joined to the holder (16) for the tool, so that movements of the driven rotatable means perpendicular " to its axis of rotation are transferred to the holder (16). 3. A device according to claim 1 or 2, c h a r a c ¬ t e r i z e d i n that the two rotatable means (43,44) are spring biassed towards each other. 4. A device according to claim 3, c h a r a c t e r ¬ i z e d i n that the freely rotatable means (43) is swingable substantially to contact the driven rotatable means (44) . 5-. A device according to claim 4, c h a r a c t e r ¬ i z e d i n that the freely rotatable means is swingable in a plane through the axis of the driven rotatable means. 6. A device according to claim 4, c h a r a c t e r ¬ i z e d i n that the freely rotatable means (42) is swingable m a plane perpendicular to a plane through the axis of the driven rotatable means. 7. A device according to claim 6, c h a r a c t e r ¬ i z e d i n that the freely rotatable means (43) is swingable about a swinging axis (39) parallel to the rotational axis of the driven rotatable means (44) . 8. A device according to claim 7, c h a r a c t e r " - l z e d i n that the swinging axis (39) is freely rotatable about the rotational axis of the driven rotatable means ( 44) . 9. A device according to claim 8, c h a r a c t e r ¬ i z e d i n that the driven rotatable means includes a shaft (30,44), on which is freely rotatably journalled a first arm (38), in which the freely rotatable means (43) 'is journalled . 10. A device according to claim 9, c h a r a c t e r ¬ z e d i n that the freely rotatable means (43) is mounted on a second arm (40) , which is swmgably journalled n the first arm (38), a spring (45) being arranged between the arms to urge the freely roatable means (43) towards the driven rotatable means (44) . 11. A device according to claim 9 or 10, c h a r c ¬ t e r i z e d i n that the first arm (38) is carried by the outer race of a rolling bearing (36), the inner race of which is mounted on the shaft (30) . 12. A device according to claim 11, c h a r a c t e r ¬ i z e d i n that the first arm (38) is mounted on the outer race by means of a clamping joint (37) . • 13. A device according to any of the preceding claims, c h a r a c t e r i z e d i n that the freely rotatable means (43) is the outer race of a rolling bearing (42) . . 14. A guide curve to be used together with a curve follower according to any of the preceding claims, c h a r a c t e r i z e d i n that it comprises an extended strip (5) of flexible material, wh.ich is adapted to be mounted in desired curve shape on a plane base (4) having the strip plane substantially perpendicular -to the base. 15. A guide curve according to claim 14, c h a r a c - t e ' r i z e d .i n that one longitudinal edge of the strip is provided with supportment and attachment lugs (25,26) bent at right angles from the plane of the strip. 16. A guide curve according to claim 14 or 15, c h ' a r a c t e r i z e d i n that one face of the strip - is provided with a band (27) of a friction increasing material . *>m

Inventors: KAELLBERG BJOERN, KAELLBERG,BJOERN
Applicants: KAELLBERG BJOERN, KAELLBERG,BJOERN
Application year: 1985
Main classification: B23Q35
IPC codes: B23Q5, B23Q35