WO1997005986A2

WO1997005986A2 - Machining apparatus and improvements relating thereto

Info

Publication number: WO1997005986A2
Application number: PCT/US1996/012777
Authority: WO
Inventors: Scott R. Kauphusman; Steve C. Mehr
Original assignee: Komo Machine Inc.
Priority date: 1995-08-03
Filing date: 1996-08-02
Publication date: 1997-02-20
Also published as: WO1997005986A3

Abstract

A machining apparatus (10) for performing machining functions on a workpiece. The apparatus (10) includes either individual or in combination, a locking mechanism for locking a workpiece support (32) to a side rail (31), a locking mechanism for locking a support pod (46) to a workpiece support (32), a tool head (19) for a rotatable tool (23) having juxtaposed bearings (77, 78), and a multi axis dust collection system (100, 103).

Description

S P EC I F I C A T I O N

TO WHOM IT MAY CONCERN:

BE IT KNOWN, That Scott R. Kauphusman, a resident of St.

Stephen, Minnesota, Stearns County, and Steven C. Mehr, a resident of St. Cloud,

Minnesota, Stearns County both citizens of the United States, have invented certain new and useful improvements in:

MACHINING APPARATUS AND IMPROVEMENTS RELATING THERETO

of which the following is a specification. Title: MACHINING APPARATUS AND IMPROVEMENTS RELATING

THERETO

This application claims the benefit of U.S. Provisional Application

Serial No. 06/001,858 filed August 3, 1995.

BACKGROUND OF THE INVENTION 1. Field of the Invention.

The present invention relates generally to a machining apparatus for performing repetitive machining operations on a workpiece, and more particularly to a point-to-point machining apparatus having an improved dust collection system, an improved gang drill assembly, and improved means for locking the panel supports and the vacuum pods.

2. Description of the Prior Art. Machining Apparatus, and more particularly, computer controlled machining apparatus or machining centers currently exist in the art. Such apparatus are designed to perform repetitive machining operations on a panel or other workpiece supported by worktable or a plurality of panel supports. Such machining apparatus include a support base, a workbed for supporting a workpiece, and a machine head carrying a plurality of machining bits or other tools. The machine head is moveable relative to the support in "x" , "y" , and "_" directions to perform selected machining functions on the workpiece.

Although currently existing machining apparatus are satisfactory for many applications, the need for improvement exists with respect to various features of such systems, including bearing support for gang drills, dust collection systems and panel support and vacuum pod locking. Accordingly, there is a need in the art for an improved machining apparatus and particularly an improved point-to-point machining apparatus addressing the above deficiencies.

SUMMARY OF THE INVENTION

The present invention relates to an improved machining apparatus, namely, a point-to-point machining apparatus having a variety of improved features.

First, the present invention includes an improved bearing support for a gang drill in which the lower bearings are staggered to permit larger bearings to be utilized. Specifically, the staggered bearing configuration allows for bearings having diameters larger than the distance between centerlines of adjacent drill openings to be utilized. This increase in bearing size reduces bearing wear and noise, among other possible advantages. Secondly, the present invention provides for an improved dust collection system, namely, a multi axis zipper duct dust collection system which virtually eliminates flexible tubing between the machine supports. In the preferred embodiment, the dust collection system includes a pair of elongated ducts positioned at right angles relative to one another with transition means for directing dust and work chips from the machine tools into one of the ducts and then into the second duct before exiting the machine through a single flexible vacuum duct. Thirdly, the present invention includes an improved mechanism

for selectively locking the panel supports in position for supporting a panel or

other workpiece.

Fourthly, the present invention provides a mechanism and device for mechanically locking individual vacuum pods relative to the panel supports to facilitate improved workpiece support and positioning.

These and other objects of the present invention will become apparent with reference to the drawings, the description for embodiment and the appended claims.

DESCRIPTION OF THE DRAWINGS

Figure 1 is an isometric view of the machining apparatus of the present invention.

Figure 2 is an isometric view of a portion of the machining apparatus of Figure 1 showing the machine head assembly and the transition between the machine head and the gantry.

Figure 3 is a side elevational view, partially in section, showing the locking piston/cylinder for selectively locking the panel supports relative to the apparatus. Figure 4 is an isometric view of a portion of one of the panel supports showing the means for locking and one of the vacuum pods connected with the panel support.

Figure 5 is a view, partially in section, as viewed along the section line 5-5 of Figure 4. Figure 6 is a view, partially in section, as viewed along the section line 6-6 of Figure 4.

Figure 7 is an isometric view, with portions broken away, of the bearing support for the gang drill of the present invention.

Figure 8 is a front elevational view, with portions broken away and partially in section, showing the staggered bearing construction of the gang drill of the present invention.

Figure 9 is a sectional view as viewed along the section line 9-9 of Figure 2. Figure 10 is an isometric view, with portions broken away, of the dust collection conduit in the gantry.

Figure 11 is an isometric, fragmentary view showing a transition dust transfer member of the type positioned between the carriage and the carriage arm duct and between the carriage arm duct and the gantry duct. Figure 12 is a sectional view as viewed along the section line 12-12 of Figure 9.

DESCRIPTION OF THE PREFERRED EMBODIMENT

The present invention relates generally to an apparatus commonly known as a machining apparatus or machining system designed to repetitively perform a variety of selected machining functions. Such machining functions are normally performed on a panel or other workpiece supported on a work table or a plurality of panel supports. More specifically, the machining apparatus of the present invention is referred to as a point-to-point machining system. The invention also relates to various improvements in the machining apparatus including an improved gang drill construction, an improved dust collection

mechanism in the form of a multiple access zipper duct dust collection system, a locking mechanism for the panel supporting vacuum pods, and an improved locking mechanism for the panel support. Figure 1 generally illustrates the machine apparatus of the present invention, while Figures 2-12 illustrate details of the above and other features of the apparatus.

Throughout the specification, the terms "machining" or "machine functions" maybe used in connection with the description of the present invention. It is intended that such terms be used in their broadest sense to define various functions or operations such as drilling, routing, shaping, milling or the like. The terms "x" axis, "y" axis and "z" axis may also be used throughout the specification. Generally, the "x" and "y" axis are horizontally disposed and define horizontal movement, while the "z" axis is vertically disposed and defines vertical movement. For the machining apparatus of the preferred embodiment, movement along the "x" axis defines lateral movement along the gantry in a horizontal plane, movement along the "y" axis defines front-back or back-front movement of the machine head along the machine head carriage arm in a horizontal plane at right angles to the "x" axis and movement along the "z" axis defines vertical movement of the machine head or the machining bits or tools at right angles to both the "x" and "y" axis.

Referring first to Figure 1, the machining apparatus 10 of the present invention includes a panel or workpiece support bed 11, a pair of side supports 12, 14 and a gantry 15. As shown, the workpiece support bed 11 is positioned between and supported by the side supports 12, 14 to support a plurality of panel supports 32. The gantry 15 is supported by the side supports 12, 14 and extends between the top ends of the side supports to support a machine head 19 and the machine head carriage arm 18. A dust collection duct 16 extends from one end of the apparatus 10. As will discussed in greater detail below, the dust collection duct 16 is in communication with the multi axis zipper duct dust collection system of the present invention. The machine head carriage arm 18 is connected with the gantry 15 for movement in a direction along the longitudinal axis of the gantry and along what is referred to as the "x" axis. As shown best in Figure 2, the gantry 15 includes a pair of spaced support rails 20 for supporting the carriage arm 18 for movement along the "x" axis relative to the gantry 15. Such relative movement between the carriage arm 18 and the gantry 15 is accomplished through a ball screw mechanism 21 illustrated best in Figure 2.

With continuing reference to Figures 1 and 2, the carriage arm 18 is an elongated member extending transversely across the machine 10 and at generally right angles to the gantry 15 such that approximately equal lengths of the carriage arm extend on opposite sides of the gantry 15. A machine head carriage 17 is connected with the carriage arm 18 for movement along the arm 18 in a horizontal direction generally perpendicular to the gantry 15 in a direction along what is referred to as the "y" axis. The carriage 17 is mounted to the arm 18 by a pair of support rails 22 and is driven by a ball screw mechanism 24. The machine head 19 is connected with the carriage 17 and is mounted for up and down movement relative to the carriage 17 in a direction referred to as the "z" axis. A plurality of head support rails 25 are connected with the carriage 17 to support the machine head 19 for such movement. Similar to movement of the carriage arm 18 relative to the gantry 15 and

movement of the carriage 17 relative to the carriage arm 18, movement of the head 19 along the "z" axis relative to the carriage 17 is accomplished by an appropriately positioned ball screw mechanism. The machine head 19 includes a plurality of machine tools or bits 23 for the purpose of providing the various machining functions or operations to the workpiece such as drilling, routing, shaping, milling or the like. The machine is also provided with a control mechanism common in the art. With reference to Figures 3 and 4, the workpiece support bed 11 is comprised of a pair of laterally spaced bed supports 29 and a plurality of collection bins 27. The bins 27 are positioned between the supports 29 and the supports 29 extend between the side supports 12, 14 and are generally parallel to the gantry 15. Mounted on the top surface of each of the bed supports 29 is a locking rail 30 and a slide rail 31 as illustrated best in Figure 3. A plurality of panel supports 32 are mounted to the slide rail 31 for movement relative to the rail 31 and thus the rail 30 and the supports 29. The supports 32 extend laterally, across the bed 11 at generally right angles relative to the gantry 15 and include a control end 33 with a handle 37 for manual movement of the supports 32. As shown in Figure 3, the bottom surface of each of the panel supports 32 is provided with a pair of rail engagement members 34 for sliding engagement with the slide rails 31. Accordingly, each of the panel supports 32 is slidable along the rails 31 in a direction generally parallel to the gantry 15 and the longitudinal axis of the machine. Certain of the panel supports 32 are also preferably provided with location pins 43 for providing accurate positioning of the panel or other workpiece.

A panel support locking means in the form of a locking piston/cylinder positioned at each end of the support 32 is provided to selectively lock the support in a desired position. As shown best in Figure 3, the locking means includes a pair of piston support brackets 35 mounted to the bottom surface of each of the panel supports 32 at a location inside of the bed supports 29. Each of the piston support brackets 35 supports a locking piston assembly comprised of a cylinder 36, a piston rod 38 and a piston rod head 39. The head 39 has a pair of beveled locking surfaces 40, 40 for selective locking engagement relative to the locking rail 30. As shown, the locking rail 30 includes an elongated locking groove 41 having a pair of beveled locking surfaces 42, 42. These surfaces correspond to, and are adapted for locking engagement with, the locking surfaces 40, 40. The cylinder 36 is provided with a pair of ports 44, 44 for selectively applying fluid pressure (pneumatic, hydraulic or the like) to the cylinder 36 for selectively moving the piston rod head 39 outwardly into locking engagement with the locking groove 41 or inwardly toward a release position in which the head 39 is out of locking engagement with the groove 41. Appropriate fluid lines are connected with the ports 44, 44 for selectively applying fluid pressure to and relieving fluid pressure from opposite sides of a piston member within the cylinder 36. The piston/cylinder is of conventional design and is available from a variety of sources.

Supply of locking pressure to, and release of locking pressure from, the piston assemblies 35 is controlled by a control button 45 positioned on an outer surface of the control end 33 of each panel support 32. By appropriate depression or other movement of the control member 45, the piston rod head 39

at each end of the panel support 32 is retracted or extended, thus releasing or

locking the panels 32 relative to the bed supports 29. When released, the panel supports 32 can be manually moved along the slide rails 31 to a desired position relative to the particular panel or workpiece to be machined.

With reference to Figures 4,5 and 6, the top surface of each of the panel supports 32 is provided with one or more vacuum pods 46 which are movable along the length of its particular panel support 32. As shown best in Figure 6, the top surface of each panel supports 32 is provided with a pair of spaced T-slots 48, 49 extending the length of the support 32. Each vacuum pod 46 includes a generally rectangularly configured base 50 and a top pad surface 51 constructed of a rubber like synthetic material for receiving the panel or

workpiece 43 (Figure 1). The top pad surface or panel engaging portion includes a continuous outer edge 52, a plurality of support portions 54 positioned within the perimeter of the edge 52 and a centrally positioned vacuum opening 55 (Figure 4). Connected with the vacuum opening 55 is a vacuum tube connected with an appropriate source of vacuum for selectively applying a vacuum to the opening 55. Each vacuum pod 46 is also provided with a locking mechanism for securely locking the vacuum pod relative to its respective panel support 32. In the preferred embodiment, such locking mechanism includes a pair of spaced locking members 57, 58 which are spaced apart and aligned relative to the pair of T-slots 48, 49 in the panel support 32. Each locking member 57, 58 includes a generally vertically extending portion 59 extending into the base portion of the vacuum pod 46 and a lower T-shaped portion 60 with a pair of laterally extending portions for sliding engagement relative to the T-slots 48 and 49. Each locking member 57, 58 is also provided with an eccentric receiving opening 61. A locking rod 62 is provided with a pair of eccentric portions 64, 64.

The portions 64, 64 are eccentric relative to the axis of rotation of the rod 62 and are designed for engagement with the eccentric openings 61, 61 in the locking members 57, 58. The end of the rod 62 is provided with an appropriate handle member 65 for rotating the locking rod 62. By appropriate rotation of the rods 62, and corresponding engagement between the eccentrics 64, 64 and their openings 61,61, the locking members 57, 58 are slightly raised, causing locking engagement between the top edges of the T-shaped ends 60, 60 and the bottom edges of the T-shaped slots 48, 49. In the preferred embodiment, the handle 65 is of a construction which enables it to be pivoted out of possible interference with the panel or workpiece, if that is a problem.

A further feature of the present invention is an improvement relating to a particular tool head for a rotatable tool usable with the present invention, namely an improved gang drill construction of the type which may be used with the machine head 19 either alone or in conjunction with other machining tools or tool heads. As shown best in Figures 7 and 8, the improved gang drill construction includes a drill bank housing 66, a separate lower deck 68 and a plurality of adjacent cylindrical drill receiving openings 69 extending through the housing 66 and lower deck 68. Each of the cylindrical openings 69 is adapted for receiving a drill assembly 70 to facilitate drilling a series of holes simultaneously in the panel or workpiece. Each of the drill assemblies 70

includes a drill bank gear having a gear portion 72, a pair of drill shaft receiving

sleeves 73 and 74 extending downwardly and upwardly, respectively, from the gear portion 72, and a locking pin opening 75 in the sleeve 74. Each set the gear portions 72 is adapted for meshing engagement with the gear portion 72 of an adjacent drill assembly. Further, one of the gear portions 72 may be driven, or a separate gear portion at right angles to the gang of gears 72 may be used to drive the entire gang as known in the art. The upper end of the sleeve 74 is journaled in a set of needle bearings 76, while the lower sleeve 73 is journaled in one of a pair of staggered upper and lower bearings 77 or 78, respectively. As shown, each of the upper bearings 77 is mounted within an opening 79 in the lower end of the housing 66, while each of the lower bearings 78 is mounted in an opening 80 in the upper end of the lower deck 68. It should also be noted that the bearings 77 and 78 are mounted in adjacent drill receiving openings in an alternating pattern. This results in a structure in which adjacent bearings 77 and 78 are staggered as shown best in Figures 7 and 8.

With this bearing structure, the bearings 77 and 78 can be larger than if they were positioned at the same level in a non-staggered relationship. This allows for the use of larger bearings, thereby resulting in increased bearing life, decreased heat and decreased noise. Accordingly, the bearings 77 and 78 are of a size which are larger in diameter than the centerline distance between adjacent drill assemblies or at least larger in diameter than bearings which could be utilized if positioned in a non-staggered relationship within the same plane. With continuing reference to Figures 7 and 8, bearing spacers 81 and 82 are positioned in the open ends of the openings 79 and 80, respectively, of the housing 66 and lower deck 68. These bearing spacers 81 and 82 function to retain the bearings 77 and 78 and to maintain the same in the desired vertically spaced relationship to one another.

Accordingly, tool head disclosed in Figures 7 and 8 can be considered as comprising a housing having a plurality of tool openings extending through the housing. In the preferred embodiment, the housing is a two part structure comprised of the lower deck 68 and the upper deck 66. In this preferred embodiment of Figure 8, the upper and lower decks 66 and 68 include surfaces which are adjacent to one another when the decks are connected. The structure also includes a first and second bearing assemblies associated with first and second adjacent tool openings. The bearings assemblies are juxtaposed relative to one another in the direction of the tool openings. One of the decks includes a bearing opening for receiving one of the bearing assemblies and the other deck includes a bearing opening for receiving the other bearing assembly. Positioned within the cylindrical central opening of the sleeves 73 and 74 is an elongated drill shaft 84 having an upper end 85 with external threads and a lower end 86 having a bit receiving recess for receiving a drill bit 23 or the like. The bit receiving recess is provided with a pair of set screws 88 for securing a drill bit 23 of desired size and specifications within the recess. The drill shaft 84 is provided with an elongated slot 89 for receiving a drive pin 90. The drive pin 90 extends through the drive pin openings 75 in the sleeve 74 and through the slot 89 to cause the drill shaft 84 to rotate with the gear assembly. The upper end 85 is connected in a conventional manner to a

piston/cylinder assembly 91 (Figure 7) for moving the drill shaft 84, and thus the

connected bit 23 upwardly and downwardly as desired. Such movement normally is between an inoperative position in which the piston assembly 91 and the drill shaft 84 are in their retracted position and an operative position in which the piston assembly 91 and the drill shaft 84 are in their extended position. A rubber or plastic gasket 92 is provided in the opening at the lower end of the lower deck 68 to prevent dust of the like from reaching the bearings 77 and 78. Reference is next made to Figures 2 and 9-11 showing details of the multiple axis zipper duct dust collection system for the machine of the present invention. In the preferred embodiment, both the gantry 15 and the machine head carriage arm 18 are provided with an elongated dust collection vacuum duct extending substantially the entire lengths of such members. Specifically, as shown in Figure 9, the gantry 15 is provided with a gantry duct 94 while the carriage arm 18 is provided with a carriage arm duct 95. Both ducts 94 and 95 are provided with an elongated access opening along one edge. Such opening is provided with a seal means to provide access for an inlet conduit at any position along the length of the duct, while maintaining the duct substantially closed and sealed at all other positions along the duct. As shown in Figures 9 and 10, the duct 94 is generally hollow throughout and has a pair of spaced opening edges 96, 96 defining an elongated opening or slot 93 extending the length of the duct 94. The seal means or closure mechanism includes a pair of flexible members or closure flaps 98, 98 having a connection end connected to the duct 94 in a position adjacent to the edges 96, 96, and a free end extending from the duct 94. The members 98, 98 are sufficiently long so that they necessarily touch one another in sealing relationship.

The duct 95 shown in Figure 9 has a similar construction in that it is generally hollow throughout and includes a pair of spaced opening edges 99, 99 defining an elongated slot 97. The closure assembly of the duct 95 is similar to that of the duct 94 and comprises a pair of flexible members or closure flaps 100, 100, each having a connection end connected to the duct 95 in a position adjacent to opening edges 99, 99 and a free end extending from the duct 95 and designed to engage each other in a sealing relationship. With continuing reference to Figure 9, the central portion of the carriage 17 may be generally open or hollow on the inside to provide for flow of dust and chips in the direction of the arrows 93 from the machining bits 23 to and through a dust transfer member 103. Alternatively, a flexible vacuum hose can be positioned with the hollow carriage 17 between the member 103 and a vacuum manifold at the lower end of the carriage 17. The dust transfer member 103 extends upwardly from the top of the carriage 17 for insertion between the closure flaps 100, 100 and into communication with the interior of the duct 95. As shown in Figure 12, the member 103 has a pointed elliptical configuration which facilitates its movement along the length of the duct 95 between the closure flaps 100, 100. With such construction, application of a vacuum to the duct 95 will result in the flaps 100, 100 engaging one another in sealing relationship, except in the area separated by the member of 103.

A similar dust transfer member 102 extends upwardly from a central portion of the duct 95 for communication with the duct 94 as illustrated best in Figure 9. The member 102 extends upwardly between the closure flaps 98, 98 and is moveable along the duct 94 to transfer dust or chips from the duct 95 to

the duct 94. Similar to the member 103, the member 102 has a pointed elliptical configuration to facilitate its movement along the length of the duct 94 between the closure flaps 98, 98. The end of the duct 94 is provided with a dust collection vacuum duct 16 connected with a vacuum source. Such duct 16 may be rigid or flexible. With this construction, vacuum hoses and lines can be virtually eliminated.

Although the description of the present invention has been quite specific, it is contemplated that various modifications could be made without deviating from the spirit of the present invention. Accordingly, it is intended that the scope of the present invention be dictated by the appended claims rather than by the description of the preferred embodiment.

Claims

I. CLAIM

1. A machining apparatus for performing machining functions on a workpiece, said apparatus comprising: first and second spaced, parallel support rails; at least one workpiece support extending from said first rail to said second rail and being supported by said first and second rails for movement along said first and second rails; and

locking means for selectively locking said workpiece support to at least one of said first and second rails, said locking means including; a first locking surface on at least one of said first and second rails and a piston assembly connected with said workpiece support including a piston having a second locking surface and being moveable between a locking position in which said second locking surface is engaged in locking relationship with said first locking surface and a non-locking position in which said second locking surface is disengaged from said first locking surface.

2. The apparatus of claim 1 wherein said piston assembly is a pressure actuated piston assembly.

3. The apparatus of claim 2 wherein said pressure is pneumatic. 4. The apparatus of claim 3 including a locking control connected with said workpiece support and moveable therewith.

5. The apparatus of claim 1 including a locking means for selectively locking said workpiece support to both said first and second rails.

6. The apparatus of claim 1 wherein said first locking surface extends substantially the entire length of said one rail.

7. The apparatus of claim 6 wherein said first locking surface includes a groove having an interior beveled surface.

8. The apparatus of claim 7 wherein said second locking surface includes an outer beveled surface for selective mating engagement with said interior beveled surface.

9. A machining apparatus for performing machining functions on a workpiece, said apparatus comprising: a workpiece support having first and second ends; at least one support pod moveable along said workpiece support between said first and second ends; and locking means for selectively locking said support pod to said workpiece support, said locking means including; a first locking surface on said workpiece support, a first second locking surface connected with said support pod and moveable between a locking position in which said second locking surface is engaged in locking relationship with said first locking surface and a non-locking position in which said second locking surface is disengaged from said first locking surface and an eccentric means for moving said second locking surface between said locking and said non-locking positions.

10. The apparatus of claim 9 including first and second space support members wherein said workpiece support/is supported by said first and second support members..

11. The apparatus of claim 9 wherein said workpiece support includes a recess extending substantially the entire length thereby, wherein said first locking surface includes a downwardly facing surface in said recess and said second locking surface includes an upwardly facing surface.

12. The apparatus of claim 11 wherein said recess is a "T" shaped slot and wherein said second locking surface is provided on a "T" shaped locking member having a portion extending into said "T" shaped slot.

13. The apparatus of claim 9 wherein said second locking surface is provided on a locking member, said locking member including an opening and wherein said eccentric means includes a rotatable rod and an eccentric member rigidly connected with said rod and positioned within said opening whereby rotation of said rod results in movement of said locking member.

14. A tool head for a rotatable tool comprising: a housing; a plurality of tool openings extending through said housing in a first direction, at least first and second of said tool openings being adjacent to one another; a rotatable tool positioned in each of said plurality of tool openings; a first bearing assembly having a first bearing surrounding said first tool opening for rotatably supporting the tool in said first tool opening; and a second bearing assembly having a second bearing surrounding said second tool opening for rotatably supporting the tool in said second tool opening, said first and second bearing assemblies being juxtaposed relative to one another in said first direction.

15. The tool head of claim 14 wherein said housing is a two part housing including a first housing portion with a first surface and a second housing portion with a second surface, said first and second housing portions being connected so that their respective first and second surfaces are adjacent to one another and define said bearing opening plane. 16. The tool head of claim 15 wherein said housing includes first and second bearing openings for receiving said first and second bearing assemblies, respectively.

17. The tool head of claim 16 wherein said first bearing opening opens to said first surface and said second bearing opening opens to said second surface.

18. The tool head of claim 17 wherein said rotatable tool is a drill.

19. The tool head of claim 14 wherein said first and second tool openings are parallel to one another and each has a longitudinal center axis which is spaced from the center axis of the other and wherein said first and second bearings are generally circular and are concentric with said longitudinal center axes of said first and second openings, said first and second bearings being of a size defined by first and second radii respectively.

20. The tool head of claim 19 wherein the distance between said longitudinal center axes of said first and second openings is at least as large as the sum of said first and second radii.

21. The tool head of claim 20 wherein said first and second radii are equal.

22. The tool head of claim 16 wherein said first and second tool openings are parallel to one another and each has a longitudinal center axis which is spaced from the center axis of the other and wherein said first and

second bearings are generally circular and are concentric with said longitudinal

center axes of said first and second openings, said first and second bearings being of a size defined by first and second radii respectively.

23. The tool head of claim 22 wherein the distance between said longitudinal center axes of said first and second openings is at least as large as the

sum of said first and second radii.

24. The tool head of claim 14 wherein at least one of said first and second bearing assemblies includes a bearing spacer.

25. The tool head of claim 16 wherein at least one of said first and second bearing assemblies a bearing spacer.

26. A machining apparatus for performing machining functions on a workpiece comprising the tool head of claim 14.

27. A dust collection system for a machining apparatus for performing machining functions on a workpiece comprising: a pair of side supports; a gantry supported by said side supports and having first and second gantry ends; a carriage arm having first and second carriage ends being mounted to said gantry for movement along said gantry between said first and second gantry ends, said carriage arm including a carriage dust collection duct; a machine head mounted to said carriage and moveable along said carriage between said first and second carriage ends, said machine head including a machine head dust collection duct; moving carriage access means for providing communication between said machine head dust collection duct and said carriage dust collection duct during movement of said machine head along said carriage.

28. The dust collection system of claim 27 wherein said gantry includes a gantry dust collection duct and said system further includes a moving gantry access means for providing communication between said carriage dust collection duct and said gantry dust collection duct during movement of said carriage along said gantry.

29. The duct collection system of claim 27 wherein said carriage dust collection duct includes a pair of spaced edges extending between said first and second carriage ends and said moving carriage access means includes a carriage closure flap of flexible material joined to each of said carriage edges, each of said carriage flaps further having inner edges spaced from said carriage edges and engaging one another to substantially seal said carriage dust collection duct, said moving carriage access means further including a dust transfer member communicating with said machine head dust collection duct and extending into said carriage dust collection duct between the inner edges of said carriage closure

flaps.

30. The duct collection system of claim 29, wherein the cross-sectional configuration of said dust transfer member is a pointed elliptical configuration.

30. The duct collection system of claim 28 wherein said gantry dust collection duct includes a pair of spaced edges extending between said first and second gantry ends and said moving gantry access means includes a gantry closure flap of flexible material joined to each of said gantry edges, each of said gantry flaps further having inner edges spaced from said gantry edges and engaging one another to substantially seal said gantry dust collection duct, said moving gantry access means further including a dust transfer member communicating with said carriage head dust collection duct and extending into said gantry dust collection duct between the inner edges of said gantry closure flaps.

32. The duct collection system of claim 31 wherein the cross-sectional configuration of said dust transfer member is a pointed elliptical configuration.