Field of Invention
This apparatus relates to routing machines and more particularly to automatic routing machines.
Description of the Prior Art
In manufacturing plants of the type wherein a large portion of the manufacturing operations involve repetitive operations, it is frequently necessary to provide machines capable of performing these repetitive operations. One of these repetitive operations frequently involves a routing operation.
In the prior art, there exists several automatic routing machines which perform the repetitive routing operations with varying degrees of success and/or difficulty. The basic automatic routing machine which exists in the prior art comprises a router which is automatically moved in the vertical direction and in a horizontal plane to complete the routing operation.
One example of such a prior art routing machine is described by Dosier in U.S. Pat. No. 3,880,047. Dosier utilizes a pneumatically actuated vertical control shaft to vertically move a spindle and its associated routing bit toward and away from the piece which is to be routed. The workpiece in the Dosier patent is secured on a laterally moveable base by a plurality of tooling pins. In operation, the Dosier machine provides the necessary routing by the coordinated vertical movement of the routing bit into the workpiece along with the lateral movement of the workpiece on the router base. Another example of a prior art routing machine is the "Router/Profiler" marketed by Paul Dosier Associates, Inc. in 1970. The Paul Dosier Associates device comprised up to four spindles which were moved in a vertical direction by a pneumatic cylinder. The workpiece which was to be routed was secured in place by tooling pins. A further example of a prior art routing machine is the "Routex" machine marketed by Advanced Controls Corporation in 1975. In addition, a general discussion of multiple-spindle, numeric controlled routing machines is given in the article entitled "An Analysis of Production and Cost Considerations--N/C Routing Vs. Blanking and Pin Routing For Printed Circuits" appearing in the December 1973 issue of "Insulation/Circuits."
These basic prior art automatic routers have several difficulties. The first of which is that inherent in a routing operation is the fact that a great amount of waste and debris is generated which is not cleaned up by this type of prior art routing machine and which results in an excessively dirty manufacturing area. Secondly, if the routing operation was of the type which formed a closed figure and was not just to form a slot or groove, when the router tool returned to the starting point, the rotational forces on the routing tool would cause the cut-out piece of the work piece to be thrown thereby causing a danger and a rough area in the routed out portion.
In order to overcome these difficulties, first a vacuum was added to the routing machine. The addition of the vacuum greatly reduced the amount of debris and waste scattered about the manufacturing area but did not eliminate the problem completely. Accordingly, brushes were added to the automatic router which contained the waste material and assisted the vacuum. The prior art brushes also reduced the problem but did not substantially eliminate it.
To overcome the problem which occurs when the router returns to the starting point in a closed loop cut-out, pins have been added to the face of the support which holds the routing tool and which engage with a pair of pin holes provided in the portion of the work piece which is to be cut out. This solution does eliminate the problem but creates its own additional problems. One of which is that the drilling of the pin holes in the work piece and the adding of pins requires additional steps and tooling in the manufacturing which results in an increase in the manufacturing cost.
Accordingly, it is the general object of the present invention to provide an automatic routing machine which is capable of routing a closed loop without requiring pins or pin holes in the to be cut out portion of the work piece.
It is another object of the present invention to provide an improved means for gathering up the waste and chips generated during the routing operation.
It is still another object of the present invention to provide an automatic router which is simple and relatively low in cost.
Summary of the Invention
In keeping with the principles of the present invention, the objects are accomplished by a unique pinless router comprising a clamp or pressure foot movable in three dimensions and arranged and configured such that it has at least one separable portion which may be decoupled from the remainder of the support, a means for vertically moving the spindle and the support, a helical brush having a large central opening concentric with the cutting tool and which engages with a work piece when the pinless router is in operation, a means for moving the spindle together with the support in a horizontal plane, a means for decoupling the separable portion from the remainder of the support and a means for supplying a continuous vacuum to the central opening in the brush.
In operation, the pinless router is first moved downwardly by the vertical movement means until the brush engages with the surface of the work piece. As the pinless router moves downwardly, the cutting tool cuts into the work piece. The routing operation is then substantially performed until just before routing of the closed loop is completed. The pinless router is then stopped and the support is moved downwardly until the separable portion of the support engages with the surface of the work piece. The separable portion is then decoupled from the remainder of the support and the routing operation is then completed. The separable portion is then recoupled to the support and the pinless router is moved upwardly and returned to the starting point.
Brief Description of the Drawings
The above mentioned and other features and objects of the present invention will become more apparent by reference to the following description taken in conjunction with the accompanying drawings, wherein like referenced numerals denote like elements and in which:
FIG. 1 shows a block diagram of a simplified basic router;
FIG. 2 is an illustration of cutting one of the images from the panel or work piece;
FIG. 3 is a cross-sectional view of a pinless router in accordance with the teachings of the present invention at the point of its operation cycle just before routing of the work piece is commenced;
FIG. 4 is a cross-sectional view of a pinless router in accordance with the teachings of the present invention showing the pinless router in that stage of its operation where it is routing the work piece;
FIG. 5 is a cross-sectional view of a pinless router in accordance with the teachings of the present invention at that stage in its cycle of operation where it is completing the routing pass; and
FIG. 6 is a cross-sectional view of the pinless router of FIG. 3.
Description of the Preferred Embodiment
Referring more particularly to the drawings, shown in FIG. 1 is a block diagram of a basic automatic router. The automatic router of FIG. 1 comprises a spindle 2 which is coupled to and moved by both on lateral means 4 and a vertical movement means 6. The lateral means 4 is old in the art and typically comprises a table and support member each coupled to a lead screw mounted at 90.degree. to each other which are controlled by servo motors. The spindle is usually mounted on the support member and the work piece is usually mounted on the table thereby creating a relative lateral movement between the two. The vertical movement means 6 moves the spindle up and down and comprises one portion of the present invention. Control means 7, controls lateral movement means 4 and vertical movement means 6 and insures that the lateral and vertical movement of spindle 6 are coordinated. Control means 7 further controls the operations of vertical movement means 6 so that it performs the functions described herein below. Furthermore, the control means 7 can be any prior art device capable of controlling the operation of lateral and vertical movement means 4 and 6 such as a tape reader, associated control circuitry, and electromechanical actuators.
Referring to FIGS. 3-6, shown therein is a pinless router in accordance with the teachings of the present invention. The pinless router comprises a spindle 2 which is coupled to the vertical movement means 6. The spindle 2 includes a chuck 5 and routing tool 8. The vertical movement means 6 comprises a pair of primary cylinders 10 which are coupled to the support member, not shown. A piston 12 is provided within each primary cylinder 10 and is coupled at one end to upper member 14. Cylinders and pistons 10 and 12 may be coupled to either a source of pressurized hydraulic fluid, not shown, or may be pneumatically actuated by compressed air.
Lower member 16 is slidably coupled to upper member 14. Spring recesses 18 are provided in the edge of lower member 16 and springs 20 extend between the spring recess 18 and a spring retainer 22 coupled to upper member 14.
Upper member 14 is further provided with a pair of secondary cylinders 24. Within secondary cylinders 24 is disposed a piston 26 having a pin member 28 which extends through holes 30 and 32 in the upper and lower members respectively. Similarly to the primary cylinder and piston 10 and 12, secondary cylinders and pistons 24 and 26 may be either hydraulically or pneumatically actuated. Furthermore, the upper end of holes 32 in lower member 16 is provided with a bevel 34.
The central section 36 of lower member 16 is substantially cylindrical in shape and extends downward from the remainder of lower member 16. Central section 32 is provided with a brush member 38 which is resiliently coupled to central portion 36 by spring member 40 such that brush 38 is capable of small movements in the vertical direction. Brush 38 comprises a plurality of stiff bristle members 42 arranged in the bottom surface in a helical pattern, as shown in FIG. 6. Furthermore, the brush 38 is provided with a large central hole 44 through which tool 8 of spindle 2 extends. The bottom portion of spindle 2 together with upper and lower members 16 and brush 38 form a chamber 46 to which a continuous vacuum is applied via vacuum fitting 48.
In operation, referring to FIGS. 2-5, the pinless router is in the condition substantially as shown in FIG. 3 just before it is lowered to begin routing at point 50 in FIG. 2. To begin routing, primary cylinders and pistons 10 and 12 are actuated thereby causing the upper and lower members 14, 16 to move downwardly from the position shown in FIG. 3 to the position shown in FIG. 4, while the vertical movement means 6 also causes the spindle 2 to move downwardly. Primary cylinders and pistons 10 and 12 are actuated until bristles 42 of brush 38 contact the top surface of the work piece 60 as shown in FIG. 4. In FIG. 4 is shown the configuration of the spindle 2 and vertical movement means during substantially all of the routing of the closed routing loop shown in FIG. 2. In this position, the work piece 60 is routing and any chips or waste which are generated during the routing process are sucked up by the vacuum applied to chamber 46 through vacuum connector 48. Furthermore, as a secondary portion of the invention, the helical disposition of the bristles 42 on the brush 38 causes the air which is drawn in by the vacuum to swirl in substantially a helical pattern. Due to this swirling effect, the chips and waste are more effectively accumulated and vacuumed up.
The routing continues as shown in FIG. 4 until just before the completion of the closed loop routing at point 52. At point 52, primary cylinders and pistons 10 and 12 are further actuated such that the bottom surface of central portion 36 of lower member 16 engages with and presses downwardly against the top surface of the workpiece 60 and holds the workpiece 60, as shown in FIG. 5. Furthermore, secondary cylinders and pistons 24 and 26 are actuated causing pin member 28 to be extracted from hole 32 in lower member 16 thereby decoupling lower member 16 from upper member 14 to allow upper member 14 to move in a horizontal direction relative to lower member 16. As the bottom surface of central portion 36 moves downward towards the work piece 60, brush 38 remains in a fixed position and spring means 40 is compressed. The last portion of the routing is then completed by moving the spindle together with the primary cylinders and pistons 10 and 12 and upper member 14 relative to the lower member 16 and the work piece 60. Since there is a large hole 44 provided in brush 38, tool 8 can be moved without contacting brush 38. Furthermore, when upper member 14 moves relative to lower member 16 one of the springs 20 is compressed while the other is allowed to expand. It should be apparent to one skilled in the art that since the tool 8 of spindle 2 has previously extended downwardly into work piece 60 to the maximum depth possible, spindle 2 is coupled to the vertical movement means 6 such that when the upper and lower member 14 and 16 are caused to be moved downwardly as shown in FIG. 5, the spindle 2 remains at its fixed depth of penetration into the work piece 60.
After the closed loop routing has been completed and the routing tool is now at point 50, primary cylinders and pistons 10 and 12 are actuated to cause the spindle together with lower and upper members 14 and 16 to move upwardly. As soon as the lower surface of lower member 16 disengages with the upper surface of the work piece 60, springs 20 cause the lower member 16 to move to a position such that the tool 8 is centered in hole 44 and pins 28 are substantially centered above holes 32 and lower member 16. Secondary cylinders and pistons 24 and 26 are then actuated to cause pins 28 to extend into holes 32 in lower members 16. The bevelled portion 34 holes 32 assist the pins 28 and help prevent the pin 28 from getting hung-up. Primary cylinders and pistons 10 and 12 continue to cause the lower and upper members 14 and 16 to move upward until the starting position shown in FIG. 3 is again achieved. At this point in time, the pinless router is ready to rout another work piece.
It should be apparent to one skilled in the art that electromechanical means could be substituted for the primary cylinders and pistons 10 and 12 and/or the secondary cylinders and pistons 24 and 26. Furthermore, it should be apparent that one could design the system such that only a single primary cylinder and piston 10 and 12 and/or a single secondary cylinder and piston 24 and 26 were utilized. Also, it is within the scope of the invention that more than two springs 20 could be utilized.
In all cases, it is understood that the above described embodiment is merely illustrative of but one of the many possible specific embodiments which can represent applications of the principles of the present invention. Numerous and varied other arrangements can be readily devised in accordance with these principles by those skilled in the art without departing from the spirit and scope of the invention.