MXPA01001335A - Drill jig assembly having hydraulic chuck and drill guide with pilot bore - Google Patents

Abstract

A drill jig assembly (1) for accurately supporting a drill (10) relative to a workpiece (83) is provided that includes a drill having a cylindrical shank (9), a chuck (7) having a cylindrical exterior, and a hydraulically-operated collet (63) for detachably gripping the drill shank (9), a housing tube (21) for slidably and rotatably supporting the cylindrical exterior of the chuck (7), and a drill guide (33) mounted on the distal end of the housing tube (21). The drill guide (33) is formed from a carbide bushing (36) having a pilot bore (38) for rotatably receiving the cylindrical shank (9) of the drill (10) and maintaining a pilot concentric alignment between the bushing (36) and the shank (9) during a drilling operation. The use of hydraulic chuck (7) in combination with the pilot bore (38) of the carbide bushing (36) allows the drill (10) to accurately bore holes in a workpiece to very tight tolerances in a one-step, extend and retract drilling operation.

Description

ASSEMBLY OF DRILL TEMPLATE WITH CHIP GUIDE AND HYDRAULIC PLATE WITH ADVANCEMENT GALLERY BACKGROUND OF THE INVENTION A This invention is generally related to drill plates, and is in special related to a drill template that uses a hydraulic drill bit in combination with a drill guide that has a feed gallery to drill holes accurately in tight tolerances. The templates for the pilot holes for performing precise drilling operations are well known in the prior art. These templates are often used in the manufacture of commercial jets where the assembly of a single wing requires the drilling of 1.5 million holes through various components of aluminum and titanium. These prior art templates are used in combination with precision-made accessories to accurately position the tip end of a drill along the center line of a desired drilling location, and then extend and retract a rotating drill with the aim of creating a hole of the desired diameter in concentric alignment with the desired location. One of the drilling templates currently used in the manufacture of aircraft wings comprises a rotating spindle connected to one end of the output shaft in an air motor, and to the handle of a drill in the other end. The spindle is placed concentric form within a housing tube (or nosepiece [heel piece] as is known in the art). The housing tube is stationary coupled to the motor housing. To provide means for advancing and retracting the bore, a screw thread is provided around the outside of the spindle. The screw thread on the spindle is connected to a screw thread provided around the internal diameter of a gear directed by the engine.

In operation, an attachment connected to the housing tube places the template in precise alignment coaxial with the centerline of the desired pierce site. Then, the air motor is driven to rotate the drill to the desired rpm. The degree of the screw thread around the spindle is dimensioned in such a way that the bore advances at the desired feed rate per revolution, which is slow enough to cut edges at the end of the drill tip to cut with cleaning and removing material from the aluminum or titanium workpiece. Once the drilling has reached the desired depth, the air motor stops and returns so that the drill thread in the spindle acts to remove the hole from the hole. Unfortunately, said template structure has shown that it is inadequate for the production of high precision perforations required in the manufacture of the wings of a commercial jet. These perforations must be drilled to a very tight tolerance, with wear (eg light tapering of the bore due to oscillations outside the center of the hole) of only about .004 inches. Because such templates can not initially produce a bore within said high tolerances, the bores must be drilled to a smaller size, and then the accuracy must be enlarged by a special reaming operation to bring them within the required tolerances. The production of said precision perforations is essential in said aeronautical components, since said components are subject to constant vibration in use, which can cause premature fatigue of the metal if the components forming the wings and other parts of the aircraft are not adjusted with precision. However, while the drilling step only takes a short time, the reaming step with additional precision required takes much more time, which significantly increases the manufacturing time for the production of each precise perforation around the spoiler. Notwithstanding another defect associated with the design j: »sa * L, í?"., ... ...., ^ .. .. * »... ^ "."!! Aa.á * g. ^ Il ^ a ^^ of prior art stencil is that it is compatible for use with only specially manufactured drills that have a tapered Mofse taper at the end of their handles to engage with the threaded end of the spindle. The installation of a Morse taper and drilling for the type 5 screw coupling not only leads to the formation of undesired non-concentricities between the spindle and the drill, but makes obsolete the change of a piece of worn drill for one new, and it is a difficult operation and waste of time, since a large part of the template must be disassembled. It is clear that what is needed is a compatible drill template to be used with an automated installation element that is capable of drilling holes in tight tolerances and with minimal wear without the need for additional time-consuming reaming steps. Ideally, such a template should also provide a quick and easy change from a worn drill to a new one. Finally, said template must be compatible to be used with holes formed in an integral way that does not require the installation of Morse tapers or special coupling components. SUMMARY OF THE INVENTION In general, the invention is a drill template assembly that overcomes the aforementioned defects associated with the prior art. At this end, the drill template assembly of the invention comprises a bore having a handle that includes a cylindrical pilot portion, a chuck that preferably includes a hydraulically operated nozzle for a removable fastener from the end of the drill handle, and a drill guide mounted in a housing tube and having a feed gallery to receive the portion of the cylindrical handle of the drill rotates. The advance gallery of the guide advantageously maintains an alignment concentric pilot between the guide and the handle portion during a drilling operation. The drill guide may include a carbide bearing having a feed gallery and a cylindrical exterior in concentric alignment with the gallery. An end cap may also be provided to secure the bearing in concentric alignment around the end of the housing tube. In the preferential characterization, the end cap includes an annular body having an internal surface that is adapted to retract in concentric alignment around the cylindrical exterior of the bearing, and an outer surface that is threaded to concentrically secure the end cap around of a distal end of the housing tube. Preferentially, the pilot portion of the drill handle is integrally formed with the cutting tip and the grooved portion of the bore hole in order to then improve the concentricity between the bore and the drill guide bearing and to minimize wear in the holes drilled by the bore. the drill. The assembly of the drill sheet of the invention may further include a thrust mechanism for rotating the chuck in the form of a spindle connected to the output shaft of a motor and having a distal end connected to the chuck. The thrust mechanism feed assembly can include a screw thread on the spindle exte, which is connected to an internal diameter screw thread in a nut rotatably driven by the motor. The motor can be reversible to rotate and advance, or rotate and retract the spindle. The housing tube may include access slots to allow the system operator to tighten or loosen the hydraulically operated nozzle of the chuck, thereby accelerating the change of holes in the assembly. An adjusting screw may be provided at the end of the hydraulically operated nozzle to provide ** a * # a degree of axial adjustment between the drill's handle and the chuck so that perforations of the same depth are produced from the small variations in the lengths of the drills used. The use of a chuck slidably supported and rotatable by a guide tube and having a hydraulically operated nozzle that applies a uniform gripping force around the end of the drill handle, in combination with a highly accurate concentric alignment achieved between the carbide bearing advance gallery and the pilot portion of the drill handle, results in a drill template assembly capable of drilling holes accurately to very high tolerances in one operation of one-step advance and retraction drilling. In addition, the use of a hydraulically operated chuck allows worn holes to be changed quickly and easily without the need to disassemble the template. The provision of an adjustable adjustment screw at the end of the hydraulically operated nozzle of the chuck conveniently allows an adjustment of the axial extension of the bore within the template caused by sharpening operations. Finally, the use of integrally formed drills will improve the concentricity achieved by the workforce and reduce manufacturing costs. BRIEF DESCRIPTION OF THE DRAWINGS Figure 1A is a side cross-sectional view of the drill template assembly of the invention; Figure 1B is a front view of the drill template assembly illustrated in Figure 1A; Figure 2 is an enlarged exploded view of the template assembly illustrated in Figure 1A in the vicinity of the distal end of the housing tube; e- ^. i --'-. , A < * ^ _¡¡¡ it * JÍ? ^ K & ^ ^ * t? ¿^ * ~ '^' ** Jté The push spindle 3 has a threaded outer 15 that includes four key slots 16 (only one of these is shown). The air motor 5 includes two separate gears (not shown), one of which includes a threaded inner diameter connecting the threaded outer 15 of a spindle 3 for the purpose of advancing and retracting it, and another having teeth along of its outer diameter connecting the key slots 16 of the spindle 3 for the purpose of imparting torsional rotation. An air motor 5 having said gear train is commercially available in the form of a Quackenbush Model No. 230-QGDA-RAC-SU-MS type air motor manufactured by Intool, Inc., located in Houston, Texas. . The thrust spindle 3 will include a chilling bore 17 which is coaxial with the coolant passage 14 of the bore 10. The distal end of the thrust screw 3 is connected to a pressurized mist type cooler source 19 as shown for the transmission cooler at through the passages 17 and 14 and out through the tip opening of the bore 13 during a drilling operation. The drill template assembly 1 further includes the aforementioned housing tube 21. The cylindrical interior 23 of the housing tube 21 is dimensioned close to the outer diameter of the hydraulic chuck 7 in such a way that the bit holder 7 is supported in part by the tube 21 when the drill template assembly 1 is oriented horizontally as shown in Figure 1A. The sliding and swiveling support provided by the housing tube 21 to the outside of the chuck 7 minimizes cantilever / cantilever loads at the end of the bore of the bore 9 which can result in undesirable amounts of wear during a drilling operation. The housing tube 21 further includes a cylindrical exterior 24 which is connected to a mounting fitting 25 (only partially shown in Figure 1 A). The mounting accessory 25 can be automated, and guides the assembly of ^^^^^^ ^^^^^^^^^^^^^^^^^^^^^^^^^^ Drill template 1 with respect to the workpiece, for the purpose of drilling a perforation of a desired diameter and depth I proximal end 27 of the storage tube 21 is connected to the air motor 5 by a screw type coupler 29. The distal end 31 of the housing tube 21 is connected to the drill guide 33. Now , with respect to Figures 1A and 2, the drill guide 33 is formed of a carbide bearing 36 having a cylindrical outer surface 37 and a concentrically aligned advancement gallery 38 around its internal surface. The advance gallery 38 rotatably supports a pilot portion 40 of the drill handle 9. At this end, the internal diameter d1 of the advance gallery 38 is dimensioned very closely to the external diameter d2 of the pilot portion 40 of the handle of the bore 9. In order to ensure minimum wear, the length of the pilot portion 40 of the bore of the bore 9 must be at least as long as a length of travel of the rotary thrust spindle 3, and the length of the bearing Carbide 36 must be dimensioned so that at least 30% of the pilot portion 40 of the handle 9 is rotatably supported by the feed gallery 38 at all times during a drilling operation. An end cap 42 secures the carbide bearing 36 in place on the distal end 31 of the housing tube 21. The end cap 42 includes an annular body having an interior 44 which is shrink fit around the concentric outer surface 47 of carbide 36 bearing to ensure a tight and precise fit. The annular body also includes a threaded outer 46 which is connectable within a thread 48 which circumscribes the internal diameter of the distal end 31 of the tube 21. The end cap 42 is provided with a stop ring 50 to limit the degree to which the threaded outer 46 of the annular body can be screwed into the thread 48 of the tube 21.

As is obvious from Figure 2, the housing tube 21 further includes an access slot 52 for a purpose that will become more apparent thereafter. Now, with respect to Figures 3A and 3B, the hydraulic chuck 7 includes a cylindrical chuck body 55 having the aforementioned cylindrical exterior 8. The proximal end of the chuck body 55 includes a threaded hole for receiving the distal end 6 ( small diameter) of the thrust spindle 3. A pair of brass adjusting screws 59a, b mounted on threaded bores 61a, b ensure the distal end to the threaded bore 57 of the bearing body 55. The chuck 7 further includes a bore clamping 62 aligned concentrically with the axis of rotation of the cylindrical chuck body 55. The clamping bore 62 includes a hydraulic nozzle assembly 63 formed of a flexible grip tube 65 surrounded by a hydraulic expansion chamber 67. A passage 67 to drive the hydraulic fluid connects to the hydraulic expansion chamber 67 with a pressure piston 71. One fits The screw 73 is provided in the pressure piston 71 to either pressurize or depressurize the fluid within the hydraulic expansion chamber 67 to either grip or release the handle end of the bore 9. A set screw 77 connected in a axially oriented threaded hole 79 is provided at the bottom of the clamping bore 62. The adjusting screw 77 conveniently allows the system operator to adjust the degree to which the end of the handle of the bore 9 can be inserted into the holding bore 62 This is an important feature, since the length of the drill 9 becomes slightly shorter each time it is sharpened. Accordingly, in order to drill holes of the same depth without making major adjustments within the other components of the drill template assembly 1, all that is needed is to turn the adjusting screw 77 counterclockwise. using a main alien socket 81. While it is not shown specifically in Figure 3B, the adjusting screw 77 includes an axially oriented passage for driving the pressurized cooler of the chilling bore 17 of the rotating thrust shaft 3 to the coolant passage 14 of the bore 9. Figures 4 and 5 illustrate the operation of the drill template assembly with respect to the workpiece 83. In operation, accessory gl 25 places the housing tube 21 in such a manner that the piercing tip 12 of the drill handle 9 is oriented along the center line of the drill. a desired drilling site. The air motor 5 is then driven for the purpose of rotating and advancing the bore.9 towards the workpiece 83. If the workpiece 83 is formed of, or includes, a titanium layer, the bore 9 rotates to a Speed of no more than approx. 350 rpm, since localized friction can cause the titanium to ignite. The degree of the screwed outer 15 of the rotating thrust shaft 3 advances the bore 9 to the desired feed average. At the same time, the pressurized cooler source provides a pressurized fog cooler from a proximal end of the shaft 3 through the cooling holes 13 located in the tip of the bore 12. Under these conditions, the tip of the bore 12 can cut with cleaning through the workpiece 83 and producing a high tolerance drilling 85 in a one-step operation. At the termination of the drilling operation, the direction of the output shaft of the air motor 5 is reversed, and the bore 10 retracts to the position illustrated in Figure 4. When the tip of the bore 12 becomes deteriorated, it is Or a simple step for the system operator to simply loosen the screw head 3 of the pressure piston 71 by extending the appropriate spanner through the access slot 52 of the housing tube 21. Then the bore 10 can be either - Sharpened or replaced by a new drill. If re-sharpened, the system operator rotates the adjusting screw 81 sufficiently to compensate for the loss of length of the bore 10 5 due to the removal of material from the bore tip 12. The system operator then tighten the thyme head 73 of the depression piston 71, and summarize the drilling operation. While this invention has been described with respect to a single preferential characterization, various additions and modifications will become apparent to those of ordinary skill in the art. All of these variations and modifications are intended to be encompassed within the scope of this patent, which is limited only by the claims appended to this document.

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Claims (20)

1. CHAPTER CLAIMING Having described the invention, it is considered as a novelty and, therefore, the content is claimed in the following: 5 CLAIMS 1. A drill template assembly for accurately supporting a drill in relation to a worce, comprises: a drill having a handle including a cylindrical portion; a chuck for detachably gripping said drill handle; 10 a housing tube for slidably supporting said chuck; and a drill guide mounted on said housing tube and having a feed gallery to rotatably receive said cylindrical handle portion of the bore and maintain a concentric pilot alignment between said guide and said handle portion during a drilling operation.
2. 2. The drill template assembly as defined in claim 1, wherein said chuck includes a hydraulically operated nozzle for applying a concentric uniform gripping force around said drill handle and allowing a rapid change of holes.
3. 3. The drill template assembly as defined in claim 1, wherein said drill guide includes a bearing having said advancing gallery.
4. The drill template assembly as defined in claim 3, wherein said drill guide includes means for securing said bearing to said distal end of said housing tube.
5. The drill template assembly as defined in claim 1, wherein at least some of said cylindrical portion of said drill handle is - -vi «atKHEattasaaia faE», Si¡.- u ÉÉÜ a a ?? * ?? »* a pilot portion that fits in said guide's said within the pilot tolerances.
6. The drill template assembly as defined in claim 1, wherein said handle is integrally formed with said drill to improve concentricity between said handle and a drilling end of said drill.
7. 7. The drill template assembly as defined in claim 1 further comprising push means for rotating said chuck.
8. The drill template assembly as defined in claim 7, wherein said biasing means includes a feed assembly for advancing and retaining said drill with respect to the worce.
9. The drill template assembly as defined in claim 8, wherein said biasing means includes a rotary spindle connected to a motor and having one end connected to said chuck and includes an external screw thread connected to a thread of screw directed by said motor to rotate, advance and retract said drill.
10. The drill template assembly as defined in claim 3, wherein said bearing of said drill guide formed of a cemented carbide material.
11. A drill template assembly for accurately supporting a drill in relation to a worce, comprising: a drill having a handle including a free end and a cylindrical portion; a chuck having a circular exterior and a hydraulically operated nozzle for releasably grasping the free end of the drill handle; _ ^ _ ^ á_¿i5_ ^ ¿_ a receiving tube to receive slidably and rotatably said circular exterior of said chuck; and a drill guide mounted at a distal end of said housing tube and having a feed gallery to rotatably receive said cylindrical handle portion of said bore and maintain a concentric pilot alignment between said gallery and said portion of the handle during a drilling operation.
12. The drill template assembly as defined in claim 11, wherein said drill guide includes a carbide bearing having said advancement gallery, and a cylindrical exterior in concentric alignment with said gallery.
13. 13 The drill template assembly as defined in claim 12, wherein said guide includes an end cap for securing said bearing to said housing tube, said end layer having an annular portion adjusted by contraction in concentric alignment about said concentric exterior of said bearing.
14. The drill template assembly as defined in claim 13, wherein at least some of said cylindrical portion of said drill handle is a pilot portion that fits into said gallery of said guide within the pilot tolerances.
15. The drill template assembly as defined in claim 11, wherein said handle is formed integrally with said drill to improve concentricity between said handle and a drilling end of said drill.
16. 16. The drill template assembly as defined in claim 11 further comprising push means for rotating said chuck. - ^ ***? * J, K *, ^. "^, ^ ^ ** ~ - - '-" "^" ** "- -
17. 17. The drill template assembly as defined in claim 16, wherein said pushing means includes a feed assembly for advancing and retracting said drill with respect to the workpiece
18. 18. The drill template assembly as defined in claim 17, wherein said biasing means includes a rotary spindle connected to a motor and having a free end connected to the motor. said drill chuck
19. 19. The drill template assembly as defined in claim 18, wherein said mechanism for feeding said pushing means includes a screw thread that surrounds the outside of said spindle and a stationary nut mounted on said motor. , wherein said motor is reversible in a rotary direction, fc
20. 20. The drill template assembly as defined in claim 11, wherein said chuck includes an adjusting screw disposed within said nozzle for adjust an axial degree to which said handle is inserted in said nozzle.