US3461750A

US3461750A - Drilling apparatus

Info

Publication number: US3461750A
Application number: US615127A
Authority: US
Inventors: Frederic Achelis; Roy J Brown; Roger M Sherman; William M Bibb
Original assignee: KOR IT CO Inc
Current assignee: KOR IT CO Inc
Priority date: 1967-02-10
Filing date: 1967-02-10
Publication date: 1969-08-19
Anticipated expiration: 1986-08-19

Description

Aug. 19, 1969 RACHELIS ETAL. 3,451,750

- DRILLING APPARATUS Filed Feb. 10, 1967 3 Sheets-Sheet l FIG.|

Aug. 19, 1969 F. ACHE LIS ETAL 3,461,750

DRILLING APPARATUS Filed Feb. 10, 1967 3 Sheets-Sheet 2 r 54a. 48 U T s 7874 32 64 3,36) Ma as 148 5 .42 I 42 12 (i) 44 I 44 38 f INVENTOR 2s 5 ig Y 5 B R8$I P J 38 34 24 ROGER MSHIERHAN WILLIAM H ems ATTORNEYS United States Patent 3,461,750 DRILLING APPARATUS Frederic Achelis, Palo Alto, Roy J. Brown, Los Gatos, and Roger M. Sherman and William M. Bibb, Palo Alto, Calif., assiguors to The Kor-it Company, Inc., Santa Clara, Calif.

Filed Feb. 10, 1967, Ser. No. 615,127 Int. Cl. B23b 41/08, 45/14 US. Cl. 77-14 Claims ABSTRACT OF THE DISCLOSURE Drilling apparatus suitable for drilling holes in tile, concrete or metallic structures, such as sewer pipe. The drill bit support can be held either by flexible connecting members or by a vacuum device to the workpiece to be drilled and the drill bit can be disposed at a right angle to the workpiece or inclined relative thereto. Pipe of substantially any diameter and flat surfaces can be drilled with the apparatus.

This invention relates to improvements in the drilling of rigid or relatively rigid structures and, more particularly, to drilling apparatus for drilling holes in tile, concrete or other pipes.

The present invention is especially adapted for the tapping of sewer mains to make house-to-sewer service connections. In the past, a number of methods have been employed to effect such connections. When sewer mains are initially laid, it is oftentimes the practice to provide for house service connections by predetermining the location of house-to-sewer lines to be laid in the future and installing stoppered Ys or Ts along the main sewer line. A location record is kept so that the Ys or Ts can be found when house service connections are made. This practice is unsatisfactory because, in many cases, the Ys or Ts become broken or cracked loose from the sewer line due to heaving of the earth. Moreover, these components are expensive, are difficult to store and ship, and are structurally weak where they are joined with sewer mains.

Sewer mains have also been tapped by the use of hand tools such as chisels, picks, and the like. Extreme care must be used in forming holes in this manner because sewer tiles are generally quite brittle and concrete pipe is quite easily cracked. It is very difficult to get even a semblance of a round hole in such pipes with hand tools. Thus, a good fit for the connecting Y or T'is not easily achieved. The disadvantages of this method are that the sewer main is oftentimes weakened, cutting time is quite long, and the irregularity of the hole size required a considerable amount of sealing compound at the joint, thus further detracting from the strength of the joints.

Still another method of tapping a sewer line is by the insertion of Ts or Ys in existing sewer lines, but this requires that the flow of the sewage in the line be interrupted during the installation, such as by pumping around the line. Techniques of this type are sometimes known in the trade as buckle-in, sisson coupling, and rollin methods. The insertion of a Y or T is not satisfactory because of flow interruption and structural weakening of the sewer line itself.

The drilling of holes in sewer mains is not new, but the apparatus that has been employed in the past to do this has several limitations. One of these limitations is that conventional apparatus can be used conveniently and with a minimum of difliculty only with a pipe having a relatively small maximum diameter. Such apparatus becomes extremely cumbersome to handle and to be connected to the pipe when the pipe diameter is greater than the afore- 3,461,750 Patented Aug. 19, 1969 "ice said relatively small maximum value. Also, conventional apparatus permits the dull bit to be disposed only at a right angle to the pipe during drilling.

The present invention provides a means by which holes can be quickly and easily drilled in sewer pipes of substantially any diameter. Even flat-surfaced tile, concrete or metal structures can be drilled with the invention. Moreover, the invention provides for the drilling of sewer pipes at an angle so that angled branch lines can be coupled thereto. To this end, the invention employs a base which can be readily secured to the pipe or workpiece either by flexible connecting members extending about the pipe or by a vacuum device drawn to and held on the workpiece by suction. A column is pivotally mounted on the base for movement into any one of the number of operative positions. Generally, the column will be held either in a position perpendicular to the pipe or in a position inclined 45 to the pipe. However, the column can be held in other angular positions as well. The column carries a rotatable shaft to which a drill bit is coupled and the drive means or the power source for the shaft is shiftably mounted on the column for movement with the shaft and the drill bit as a unit.

The drilling apparatus of the invention is relatively lightweight so that it can be moved from place to place with a minimum of effort. It allows for quick interchange between the flexible connecting members which surround the pipe and the vacuum device which adheres to the outer surface of the pipe. When the vacuum device is not to be used, it can be retracted into a recess in the base and carried as a part of the base itself.

Provision is also made for improving the cooling of the drill bit and the flushing of the cut formed in the pipe as it is drilled. To this end, the shaft for rotating the drill bit has an improved outlet orifice for a coolant which effectively Wets the entire inner surface of the drill bit regardless of the angle it makes with the pipe to be drilled. Also, the drill bit itself has small holes adjacent to its cutting end through which the coolant may pass so that the cut on both sides of the drill bit will be lubricated and thereby flushed.

It is, therefore, the primary object of this invention to provide an improved drilling apparatus for forming holes in cementitious, metallic or other rigid or relatively rigid structures wherein the apparatus is constructed so that it can be easily and quickly set into a drilling position on a pipe of substantially any diameter, as well as a flatsurfaced block.

Another object of this invention is to provide drilling apparatus of the type described which can be attached to a tile or concrete pipe either by flexible connecting members extending about the pipe or by a vacuum device drawn to the outer surface of the pipe by suction, whichever meansis the more convenient for use with a particular workpiece, so that the apparatus is not limited to any specific workpiece size or to a specific range of pipe diameters and it can be used in drilling pipe disposed below the surface of the ground or in proximity to adjacent structure without disturbing the adjacent soil mass or damaging or otherwise disturbing the adjacent structure.

A further important object of this invention is to provide drilling apparatus of the aforesaid character wherein a pivotally mounted column movable into any one of a number of operative positions with respect to a workpiece shiftably mounts the drill bit so that holes can be drilled in tile or concrete pipe at an angle to accommodate angled branch lines for minimizing initial construction costs of the lines.

Other objects of this invention will become apparent as the following specification progresses, reference being had to the accompanying drawings.

In the drawings:

FIGURE 1 is a side elevational view of the drilling apparatus in a position to drill a tile or concrete pipe at an angle, a second operative position of the apparatus being shown in dashed lines;

FIGURE 2 is a cross-sectional view taken along line 22 of FIGURE 1;

FIGURE 3 is a cross-sectional view taken along line 33 of FIGURE 1;

FIGURE 4 is a view similar to FIGURE 3 but illustrating the use of the vacuum device instead of the flexible connecting members of FIGURES 1 and 3;

FIGURE 5 is a fragmentary, side elevational view of the apparatus illustrating the way in which the vacuum device is coupled to the base of the apparatus; and

FIGURE 6 is a cross sectional taken along line 66 of FIGURE 5.

Drilling apparatus 10 includes a base 12, a column 14 pivotally mounted on base 12, a carriage 16 shiftably mounted on column 14 for movement longitudinally thereof, a drive shaft 18 journalled on carriage 16 for rotating cylindrical drill bit 20, and drive means 22 coupled with shaft '18 for rotating the same relative to the carriage. FIGS. 1-3 show how base 12 is coupled by a pair of flexible coupling members to a workpiece; whereas, FIGS. 46 show how the base is coupled by a vacuum device to a workpiece. The workpiece illustrated in the drawings is a pipe 24 formed of tile or concrete and having a predetermined wall thickness through which a hole is to be formed. As will hereinafter be made clear, the invention is not limited to the drilling of pipe of this type, but can be used for drlling into metal pipes as well as metal and cementitious blocks, as well as other rigid or relatively rigid structures.

Base 12 has a rectangular frame-like configuration and includes a pair of generally parallel, transversely L-

shaped sides

26 and 28 which are interconnected by bar-like ends 30 and 32 (FIG. 3). Each of the

sides

26 and 28 has a pair of mutually

perpendicular flanges

34 and 36, each flange 34 having a pair of spaced levelling screws 38 disposed for engaging pipe 24.

Flange 36 of side 26 has a pair of spaced, open end slots 40 for receiving links 42 of respective link chains 44 which serve to releasably couple base 12 to pipe 24. The width of slots 40 is greater than the thickness of each link 42 so that the links can be easily received in the slots. However, the width of the links is greater than the slot width so that the next adjacent link of each chain will abut the inner surface of flange 36 and thereby prevent outward movement of the chain with respect to the slots. The chain is thereby releasably held or coupled to base 12.

Flange 34 of side 28 has a pair of open end slots 46 (FIGS. 3 and 4) for receiving take-up devices 48 on the corresponding ends of chains 44. Each device 48 includes an internally threaded sleeve 50 and an externally threaded shaft 52 movable within the sleeve. Each slot 46 has an enlarged inner extremity which is surrounded by conical surface 54 formed by countersinking the area surrounding the enlarged portion of the slot. Each sleeve 50 has an end substantially complemental to and normally bearing against the corresponding surface 54 so that the rotation of the sleeve to take up slack in the corresponding chain is facilitated.

Column 14 has a box-like, tubular construction and is provided with a pair of laterally extending arms 56 which are tapped at their outer ends for threadably receiving screws 58 passing through respective, aligned holes 60 in flanges 36. For purposes if illustration, column 14 is adapted to be mounted in two different positions on base 12. As shown in FIGS. 1, 3, 4, and 5, column 14 is mounted in proximity to end 30. In this position, the drill bit will be outboard of end 30 and thereby externally of base 12 as shown in FIG. 1. To assist in guiding the column into this position, a pair of guide members 62 are secured to the inner surfaces of respective flanges 36 and have V- 4 shaped guide surfaces 64 (FIGS. 1, 3 and 4) which define shoulders for supporting the outer ends of respective arms 56. When the arms are supported by guide members 62, the tapped openings in the arms will be aligned with the holes in flanges 36 to facilitate the coupling of screws 58 to the arms.

Another position for column 14 is inboard of the position shown in the drawings. To this end, guide members 66, identical to guide members 62, are secured to flanges 36 adjacent to respective holes 60 for supporting arms 56 as screws 58 are threaded into the arms. In the more central position, column 14 is disposed to mount drill bit 20 inboard of side 30 to enhance the stability of the unit. For this position, column 14 will be perpendicular to the plane of base 12. For the first mentioned position of the column, the latter can be perpendicular or inclined relative to the plane of the base. When it is perpendicular in the first position, the drill bit is capable of drilling near the bell end of pipe 24.

. The outer end of column 14 has a pair of cars 68 connected by a pin 70 to a rod 72 telescoped within and extending outwardly from one end of a tubular member 74. The opposite end of member 74 is connected by a pin 76 to a pair of ears 78 rigid to end 32 of base 12 (FIG. 3). Screws 58 and pins 70 and 76 provide pivotal mountings so that column 14 can be pivoted into any one of a number of operative positions with respect to base 12. To hold the column in a fixed position, rod 72 is provided with a number of holes along its length for receiving a pin 80 which is removably carried at the outer end of tubular member 74. Generally, column 14 will either be inclined at a 45 angle with respect to base 12 as shown in full lines in FIG. 1 or at right angles to the base as shown in dashed lines in FIG. 1. However, it can be at any angle provided drill bit 20 is capable of drilling a hole in the workpiece.

Carriage 16 includes an elongated, transversely C- shaped guide 82 which is complemental to and slidably disposed on column 14 as shown in FIG. 2. A pair of rigid straps 84 (FIG. 1) releasably interconnect guide 82 to the column and allow it to shift longitudinally of the column.

To shift carriage 16, a screw 86 is provided, screw 86 being rotatably mounted on a laterally extending projection 88 at the outer end of column 14 (FIGS. 1 and 2). The screw is also threadably coupled to a sleeve (not shown) rigid to guide 82 so that when the screw is rotated, the guide is advanced along column 14. A handle 90, on the outer end of screw 86 allows the same to be rotated in opposed directions, whereby guide 82 may be reciprocated with respect to the column.

A pair of spaced bearing mounts 92 are secured to and extend laterally from guide 82 in a direction away from base 12 when column 14 is inclined. Mounts 92 have bearings 93 for rotatably mounting shaft 18 on carriage 16 in substantial parallelism to column 14. A sprocket 94 is rigidly coupled to shaft 18 and is connected by a chain 96 to a sprocket 98 on the drive shaft 100 of a power source 102 forming drive means 22. Power source 102 is connected by a bracket 104 to guide 82 so that it reciprocates with carriage 16. It can be of any construction, such as an electric motor, a hydraulic motor, a gasoline motor, or an air motor. An air motor is preferred over an electric motor for reasons of safety because apparatus 10 will oftentimes be used in damp or wet areas below ground level. Also, if the motor is air driven, it can serve the additional purpose of actuating the vacuum coupling device hereinafter described.

Shaft 18 is threaded at one end and is axially connected to drill bit 20 in any suitable manner, such as by a pair of coupling elements 106 on opposed sides of the end wall 108 of the drill bit. Shaft 18 is tubular so that a coolant can be directed into drill bit 20. A conduit 109 is coupled to the outer end of shaft 18 and is adapted to be connected to a source of coolant, such as water. The

inner end of shaft 18 threadably receives a tip 110 having a T-shaped passage 112 defining a pair of opposed outlet ports communicating with the interior of shaft 18. By means of this construction, the coolant issues laterally of the longitudinal axis of the shaft and more effectively wets the interior of drill bit 20 than if the coolant were to issue axially of the shaft. With this construction, more surface area of the interior of the drill bit is covered by the coolant and the drill bit is thereby more effectively cooled than an axial flow of coolant from the shaft.

To enhance the lubrication of the cut made by drill bit 20, the latter is provided with a number of spaced, relatively small holes 114 therethrough adjacent to its cutting end. These holes allow the coolant to pass through the drill bit and thereby lubricate both sides of the cut.

Chains 44 are one means of securing base 12 to a workpiece and may conveniently be used when the pipe diameter is not too large. Generally, the chains will be used for pipe diameters in the range of 6" to 12" and where digging around the pipe can be done without much difficulty. Beyond this upper limit, it may be more practical to use vacuum attachment 116 (FIGS. 4-6) to eliminate the digging step. Attachment 116 is drawn by suction to the outer surface of the pipe and means is provided to connect the base to the attachment, whereby the base is rigidly held to the pipe for the drilling operation. This attachment can also be used for pipe in the small diameter range if the construction of the attachment is such as to allow for this.

Attachment 116 includes a plate 118 having continuous inner and outer flanges 120 and 122 (FIG. 6) on one face for defining a continuous recess 124. A continuous, resilient band or pad 126 is disposed within recess 124 and is engageable with the outer surface of pipe 24. The end portions of

flanges

120 and 122 have arcuate edges 128 which are slightly concave to follow somewhat the outer contour of pipes in a certain diameter range. To facilitate the forming of these edges, the plate 118 itself is slightly arcuate. The inner flange 120 and the central portion of 118 defines a vacuum chamber 130 when pad 126 engages pipe 124. A vacuum device 132 mounted on the outer face of plate 118 communicates with chamber 130 for evacuating the same. Device 132 is preferably a venturi unit which is coupled by a conduit 134 to a source of air under pressure. Conduit 134 is coupled with the pressure source which actuates motor 102 if the latter is of the air-driven type. A vacuum gauge 136 is carried by plate 118 and communicates also with chamber 130 for registering the suction pressure in the chamber.

Plate 118 is releasably coupled to base 12 by means of a pair of tubular crosspieces 138 which span the distance between flanges 36 of

sides

26 and 28 as shown in FIG. 6. The ends of crosspieces 138 have notches 140 for complementally receiving the upper edges of the flanges 36 to thereby hold the crosspieces in place on the base.

Crosspieces 138 are coupled with plate 118 by a pair of threaded stub shafts 142 which are threadably coupled to bosses 144 integral with the outer surface of plate 118 (FIG. 5). The shafts 142 extend outwardly from plate 118, through respective crosspieces 138 and pro ect outwardly therefrom. A nut 146 is threadably coupled to the outer end of each shaft 142 and is disposed to draw plate 118 and crosspieces 138 together.

Each flange 36 has a pair of pin-like stops 148 which extend into the central opening 150 defined by the sides and ends of base 12. Stops 148 are adjacent to the outer edges of flanges 36 and are used to hold plate 118 in a retracted position recessed within central opening 150. FIG. 6 illustrates the approximate position of plate 118 when it is retracted. To retract the plate, nut 146 is tightened to draw the plate against stops 148 whereupon attachment 116 becomes rigid with base 12. The apparatus can then be used with chains 44 or can be carried from place to place with attachment 116 rigidly held thereon.

6 OPERATION When a hole is to be drilled into small diameter pipe in the ground, the pipe is exposed and base 12 is placed on it in line with the area to be drilled. The soil beneath the pipe is also dug away to permit the chains to extend about the pipe.

With take-up devices 48 in place, the chains are positioned about the pipe and pulled to take up the slack. Then a link of each chain is placed in. the corresponding slot while the chain remains as taut as possible. Then the take-up devices are actuated to tighten the chains and thereby rigidly secure the base to the pipe.

Drill bit 20 can be secured to shaft 18 either before or after the base is put into place. If an angled hole is to be drilled, column 14 is positioned in prixitnity to side 30 as shown in FIG. 1 and at the proper angle relative to base 12 by adjusting the relative positions of rod 72 and tubular member 74. Motor 102 is then coupled to a power source and conduit 109 is coupled to a source of water for cooling. The Water flow is started before the drilling is initiated.

If the bell end of pipe 24 is to be drilled, column 14 will be moved into the dashed line position of FIG. 1. Where maximum stability of the drill bit is desired, column 14 is initially positioned in the more central position where drill bit 20 extends through central opening 150 of base 12. When used in this manner, attachment 116 is removed from the base.

With shaft 18 rotating and water flowing into drill bit 20, screw 86 is rotated by the manual rotation of handle to advance carriage 16 progressively along column 14. Drill bit 20, thus, moves into drilling engagement with pipe 24 and progressively drills the same. The rate at which the carriage is advanced will depend upon the rotational speed of shaft 18 and the type of material forming pipe 24.

During the drilling operation, water is directed laterally from tip 110 and wets substantially the entire inner surface of drill bit 20 to cool the same. The Water, also, flows to the drilling area and into one side of the cut as well as through holes 114 and to the opposite side of the cut. In this way, the cut is more effectively flushed to enhance the drilling step itself.

After the drilling has been completed, the portion removed from the pipe can be readily removed from the drill bit after the latter has been moved away from the pipe and its rotational movement stopped. The drill bit is moved away from the pipe by rotating screw 86 in the opposite direction.

If the pipe diameter is above the range at which it is practical to use chains 44, the chains are not used and attachment 116 is employed. To utilize the attachment, it is first loosely coupled to the base so that there can be relative movement between these components. Plate 118 is then forced toward the pipe to cause pad 126 to compress as it engages the pipe. Then, vacuum device 132 is actuated to evacuate chamber 130. This holds plate 118 by suction to the pipe, whereupon nuts 146 can be tightened to force base 12 toward the pipe and into a fixed position with respect to attachment 116. The drilling step can then be performed with column 14 either perpendicular to or at an angle to the pipe. The water flow is provided in the usual manner to cool the drill bit and to flush the cut.

Leveling screws 38 are generally used when attachment 116 is used. They are generally not needed for the smaller diameter pipe since each of the

ends

30 and 32 has an arcuate edge proximal to the pipe which provides a pair of contact points which are transversely spaced relative to the longitudinal axis of the pipe. Within a certain range of pipe diameters, these contact points serve to align the base longitudinally of the pipe when the base is first put into place. Above this range, the contact points become less effective and, generally, the

leveling screws should then be substituted for this alignment feature. The leveling screws themselves then become point contacts engaging the pipe.

The leveling screws also serve to support apparatus 10 when the latter is not in use. In this respect, the screws protect pad 126 from damage when attachment 116 is retracted into base 12.

Apparatus 10 is also suitable for use in drilling flat surfaces. To this end, the workpiece-engaging pad of plate 118 will have a working face that is planar rather than one that is arcuate as shown in FIG. 6. Thus, the invention is not limited to the drilling of pipe.

Apparatus It) provides a driling unit having a simple and rugged construction and one which is highly portable and can be quickly and easily set up for use either on tile or concrete pipe or a flat-surfaced cementitious structure.

While one embodiment of this invention has been shown and described, it will be apparent that other adaptations and modifications can be made without departing from the true spirit and scope of the invention.

What is claimed is:

1. Drilling apparatus comprising: a base frame having a pair of opposed sides and a pair of opposed ends defining a central opening, each of said sides being transversely L-shaped to present a pair of interconnected flanges, one flange of one of the sides having a pair of spaced, open end slots therein, one flange of the other of said sides having a pair of spaced, open end slots therein aligned with respective slots of said one side; a pair of link chains adapted to extend about said workpiece to couple the base frame thereto when the perimeter of the workpiece is less than a predetermined value, each chain having a take-up device at one of its ends, the takeup device is adapted to extend through the slots of said one side and toengage said one side to thereby releasably couple the corresponding ends of the chains to the base frame, the slots of the other side having a width less than the width of the links of corresponding chains but greater than the thickness of said links to thereby permit the links of said chains to be selectively placed into the lastmentioned slots to couple the opposite ends of the chain to the base frame, whereby the latter may be secured t the workpiece when the take-up devices are actuated to tighten said chains; a vacuum plate having a resilient, workpiece-engaging, continuous band defining a vacuum chamber when the band engages said workpiece; a vacuum device carried by said plate and adapted to be connected to a vacuum source for evacuating aid chamber; means carried by said plate for shiftably mounting the latter on said base frame with the plate being aligned with said central opening thereon, said mounting means including structure for urging said base frame toward said plate when the latter is held to said workpiece by suction, whereby the base frame may be moved into a fixed position relative to said plate when said chains are not used, each of said sides having a stop extending into said central opening, said structure being disposed to move said vacuum plate into a retracted location Within said central opening and against said stops When said chains are to be used to couple said base frame to said workpiece; a column having a carriage mounted thereon for longitudinal movement with respect thereto; means pivotally mounting one end of said column on said sides adjacent to one end of the base frame for movement in a plane substantially perpendicular to the plane of said base frame, said column being movable into any One of a number of operative positons with respect to the plane of said base frame; means carried by said base frame and coupled with said column for releasably holding the same in an operative position; a tubular shaft journalled on said carriage in substantial parallelism with said column; drive means mounted on' said carriage for rotating said shaft; a cylindrical drill bit; means releasably and axially mounting one end of the drill bit on said shaft with one end of the shaft extending into the drill bit, the latter having a number of holes therethrough adjacent to the outer end thereof; a tubular coupling secured to said one end of the shaft and having a T-shaped fluid passage therethrough, said passage communicating with the interior of said shaft to cause a coolant entering said shaft at a location adjacent to its opposite end to issue from said coupling in opposed directions and laterally of the longitudinal axis of the shaft; and a screw carried by said column and coupled with said carriage for reciprocating the latter with respect to said column.

2. Drilling apparatus as set forth in claim 1, wherein said drive means includes an air motor adapted to be coupled to a source of air under pressure, said vacuum device having a venturi section coupled with said air motor to produce a vacuum in said chamber when said band engages said workpiece.

3. Drilling apparatus as set forth in claim .1, wherein said holding means for said column includes an extensible, adjustable brace secured to the opposite end of the column and to said base frame adjacent to the opposite end thereof.

4. Drilling apparatus as set forth in claim 1, wherein said ends of the base frame have means defining spaced contact points for engaging the workpiece and aligning the base frame with respect thereto when the workpiece has a convex outer surface, each of said sides of said base frame having a pair of spaced leveling screws for engaging the workpiece when said defining means become ineffective for aligning said base frame.

5. Drilling apparatus comprising: a base having a central opening and a pair of spaced sides and adapted to be disposed adjacent to a workpiece to be drilled; a vacuum device disposed in said opening and disposed for fixedly engaging said workpiece to secure the base to the outer surface, said vacuum device having a pair of spaced crosspieces shiftably mounted thereon, said crosspieces being disposed to engage the opposite sides of said base in bridging relationship thereto; means for forcing said crosspieces and thereby said base toward said vacuum device when the latter fixedly engages said workpiece and when said crosspieces engage the sides of said base, whereby the base is held in a fixed location relative to said vacuum device; a column pivotally mounted on said base for movement in a plane extending transversely of said outer surface when the base is secured thereto; means coupled with said column and carried by said base for releasably holding said column in any one of a number of operative positions with respect to said surface; a carriage shiftably mounted on said column for movement longitudinally thereof; a drill bit rotatably mounted on said carriage and disposed for drilling said surface when said column is in an operative position and as said carriage moves toward said workpiece; drive means on said carriage for rotating said drill bit; and means mounted on said column and coupled with said carriage for controllably moving the latter along said column, whereby said drill bit may be progressively moved toward and into drilling engagement with said surface.

6. Drilling apparatus as set forth in claim 5, wherein each side of said base is provided with a stop extending into said opening, said forcing means including a screw disposed for shifting said vacuum device into a retracted position in engagement with said stops.

7. Drilling apparatus as set forth in claim 5, wherein the ends of each of said crosspieces are notched to receive the corresponding sides of said base and thereby to releasably maintain said crosspieces in bridging relationship to said sides.

8. Drilling apparatus comprising: a base adapted to be disposed adjacent to a workpiece to be drilled, said base being provided with a pair of arcuate end edges for engaging said workpiece when said outer surface thereof is convex; a number of leveling screws shiftably carried by said base and disposed for engaging the outer surface of said workpiece when the curvature of said outer surface is less than the curvature of said end edges; means coupled with said base for releasably securing the latter to the outer surface of said workpiece; a column pivotally mounted on said base for movement in a plane extending transversely of said outer surface when the base is secured thereto; means coupled with said column and carried by said base for releasably holding said column in any one of a number of operative positions with respect to said surface; a carriage shiftably mounted on said column for movement longitudinally thereof; a drill bit rotatably mounted on said carriage and disposed for drilling said surface when said column is in an operative position and as said carriage moves toward said workpiece; drive means on said carriage for rotating said drill bit; and means mounted on said column and coupled with said carriage for controllably moving the latter along said column, whereby said drill bit may be progressively moved toward and into drilling engagement with said surface.

9. Drilling apparatus comprising: a base adapted to be disposed adjacent to a workpiece to be drilled; means coupled with said base for releasably securing the latter to the outer surface of said workpiece; a column pivotally mounted on said base for movement in a plane extending transversely of said outer surface when the base is secured thereto; means coupled with said column and carried by said base for releasably holding said column in any one of a number of operative positions with respect to said surface; a carriage shiftably mounted on said column for movement longitudinally thereof; a tubular shaft journalled on said carriage; a drill bit for drilling said surface when said column is in an operative position and as said carriage moves toward said workpiece, said drill bit including a tubular member secured to and partially telescoped on said shaft, the inner end of the shaft having a laterally extending fluid outlet, whereby a coolant directed through said shaft Will issue from said inner end thereof in a direction transverse to its longitudinal axis; drive means on said carriage for rotating said drill bit; and means mounted on said column and coupled 'with said carriage for controllably moving the latter along said column, whereby said drill bit may be progressively moved toward and into drilling engagement with said surface.

10. Drilling apparatus comprising: a base having a pair of spaced, opposed sides and a pair of spaced, opposed ends defining a central opening, said base adapted to be disposed adjacent to a workpiece to be drilled; means coupled with said base for releasably securing the latter to the outer surface of said workpiece; a column; a carriage shiftably mounted on said column for movement longitudinally thereof; a drill bit rotatably mounted on said carriage and disposed for drilling said surface when the column is in an operative position with respect thereto and as said carriage moves toward said workpiece; first means on said sides of the base for mounting said column for pivotal movement in a plane extending transversely of said outer surface and for positioning said drill bit exteriorly of and adjacent to one of the ends of the base; second means for mounting said column at a location with said drill bit movable through said central opening; means coupled with said column and carried by said base for releasably holding said column in an operative position with respect to said surface; drive means on said carriage for rotating said drill bit; and means mounted on said column and coupled with said carriage for controllably moving the latter along said column, whereby said drill bit may be progressively moved toward and into drilling engagement with said surface.

References Cited UNITED STATES PATENTS 3,169,415 2/1965 Welty 77-42 XR 2,977,827 4/1961 Wenz 77-68 XR 2,887,910 5/1959 Williamson 7759.1 2,222,910 11/ 1940 Lucker 77--14 XR FOREIGN PATENTS 451,950 8/1936 Great Britain. 583,158 12/1946 Great Britain.

FRANCIS S. HUSAR, Primary Examiner US. Cl. X.R.