US3833073A

US3833073A - Floor tap insert drill

Info

Publication number: US3833073A
Application number: US00379586A
Authority: US
Inventors: C Carver
Original assignee: Individual
Current assignee: Individual
Priority date: 1973-07-16
Filing date: 1973-07-16
Publication date: 1974-09-03
Anticipated expiration: 1991-09-03

Abstract

Drill for successively drilling holes of different diameters. A circular hole saw is affixed to one end of a shaft, and a cylindrical core bit is slidably mounted on the shaft and movable between extended and retracted positions relative to the hole saw. Means is provided for releasably locking the core bit in its extended position, and shift mechanism is provided for operating the lock means and moving the core bit between the extended and retracted positions.

Description

United States Patent 1 1 1111 3,833,073

Carver Se t. 3, 1974 [5 FLOOR TAP INSERT DRILL 3,151,690 10/1964 Grable 175 321 3,273,930 9/1966 Gottfried [76] Invent: g g ig gi 3,736,995 6/1973 Salter 175/387 x an ranc1sco, a1

[22] Filed: July 16, 1973 Primary Examiner-David H. Brown Attorney, Agent, or FirmFlehr, Hohbach, Test, 1 Appl' 379586 Albritton & Herbert [52] US. Cl 175/173, 175/202, 175/262, 57%, ABSTRACT 175/313, 175/315,175/33O [51] Int CL Ezlc 1/14 E2) 9 /36, E2) 11/00 Dnll for successively drilling holes of different diame- [58] Field of Search 173/21 5/171 173 ters. A circular hole saw is affixed to one end of a 175,202 220 7 262 5 shaft, and a cylindrical core bit is slidably mounted on.

6 the shaft and movable between extended and retracted positions relative to the hole saw. Means is [56] References Cited provided for releasably locking the core bit in its extended position, and shift mechanism is provided for UNITED STATES PATENTS operating the lock means and moving the core bit be- :ensen et tween the extended and retracted positions.

0y 2,599,770 6/1952 Marcerou 175/403 X 13 Claims, 7 Drawing Figures 4- 1 -3- 464 1 lli .46 46A 43 c 3 a: [I //a i i a E l :9 I a: 1 I 56 i j! 2/ I: I ll: 22 5 9: El 3 J E g I]: i j .E '1 i a 11 5g 3 1'? E 1, j 3 1 j PATENTUJ' SEP 3 i 74 snmaor 2 iiiiiiiiiiilziiiii Q a 1 FLOOR TAP INSERT DRILL BACKGROUND OF THE INVENTION suitable for use in the installation of floor tap'inserts in buildings having utility passages or ducts embedded in concrete flooring.

In the construction of new buildings, such as office buildings and the like, the floor structure commonly includes transversely extending utility passages adapted to contain electric cables and the like. These passages or ducts are typically constructed of sheet metal, and they are embedded in concrete which is poured on top of them. When the floor plan is known and the location of utility outlets is determined, holes are cut through the concrete flooring and the metal cover of the utility passage, and utility outlet fixtures (commonly known as floor tap inserts) are installed in the holes. With a widely used type of floor tap insert, the'hole in the metal cover is smaller in diameter than the hole in the concrete to provide a lip which is used to hold the insert in place.

Heretofore, the holes for floor tap inserts have generally been drilled in a two-step operation, using separate drills. In the first step, a masonry core bit is used to cut through the concrete flooring to the metal cover of the utility duct. The core bit is then removed and replaced by a circle saw suitable for'cutting through the metal cover. Changing drills is a time-consuming procedure, and special care must be taken to assure that the hole in the metal cover is properly aligned with the hole in the concrete. In one prior art device, a hole saw is rectractably mounted in the barrel of a core bit and held in extended and retracted positions by spring loaded pins-which can be depressed to raise and lower the hole saw. Although this device eliminates the need for changing drills and at least partly overcomes the problem of hole alignment, it is awkward to use because the drill must be stopped before the hole sawcan be moved in either direction. Also, a workman must bend over to move the hole'saw, and this is a tiring procedure, particularly where a large number of holes are being drilled,.as is the case in most new buildings. Furthermore, the pins which hold the hole saw extend through openings in the core bit, and Coolants and lubricants supplied to the core bit can leak through these openmgs.

SUMMARY AND OBJECTS OF THE INVENTION The invention provides a floor tap insert drill having a shaft, a circular hole saw affixed toward one end of the shaft, and a masonry core bit which is constrained for rotation with the shaft and movable axially of the shaft between extended and retracted positions relative to the hole saw. A resilient member urges the core bit toward its retracted position, and a lock ring, which can be operated when the drill is turning, holds the core bit in its extended position. A shifter assembly is provided for actuating the lock ring and moving the core bit between its extended and retracted positions.

It is in general an object of the inventionto provide a new and improved drill for successively cutting holes of different diameters.

Additional objects and features of the invention will be apparent from the following description in which the preferred embodiments are set forth in detail in conjunction with the accompanying drawings.

' BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is an isometric view, partly cut away, of one embodiment of a drill according to the invention, with the masonry core'bit in its extended position.

FIG. 2 is a center line sectional view, partly cut away, of the embodiment shown in FIG. 1, with the masonry core bit in its retracted position.

FIG. 3 is a cross-sectional view taken along line 3-3 in FIG. 2. 7

FIG. 4 is a fragmentary sectional view, illustrating an alternative structure for centering the hole saw and core bit.

FIG. 5 is a fragmentary'elevational view, partly sectioned, of another embodiment of a drill according to the invention.

FIG. 6 is a cross-sectional view taken along line 6-6 in FIG. 5.

FIG. 7 is a cross-sectional view taken along line 7-7 in FIG. 5.-

DESCRIPTION OF THE PREFERRED EMBODIMENTS As illustrated in FIGS. 1-3, the drill includes an axially extending shaft ll, 21 hole saw 12 affixed to the shaft toward one end thereof, and a generally cylindrical masonry core bit 13 constrained forrotation with the shaft and movable between axially extended and retracted positions relative to the hole saw. In the extended position, which is illustrated in FIG. 1, the core bit extends beyond the hole saw and is in position to cut through concrete flooring 16. When the core bit is in its retracted position, as illustrated in FIG. 2, the hole saw is exposed below the open end of the core bit and in position to cut through the top wall 17 of a utility passage or duct 18.

Shaft 11 includes a top portion 11a and a bottom portion llb of non-circular cross section and a portion 110 of a circular cross section intermediate the top and bottom portions. Radially extending

shoulders

21 and 22 are formed at the ends of non-circular portions 11a and 11b adjacent to circular portion 110. In the embodiment illustrated, the non-circular portions of the shaft have a square cross section, and it will be understood that thesev portions can have another non-circular cross section if desired.

A threaded coupling 24 is rigidly affixed to the upper end of shaft by suitable means such as welding. This coupling provides means for connecting the drill to the vertical output shaft of a conventional drilling machine.

-An axially extending threaded boss 26 is provided at saw and yieldably extends beyond the cutting edge of the saw for ejecting sheet metal cutouts therefrom. In the preferred embodiment, the spring is spirally wound, and its upper convolutions are threadedly mounted on boss 26 below the base of the hole saw.

Masonry core bit 13 is a diamond tipped core bit having an elongated cylindrical barrel 130 with a cutting edge 13b at the lower end of the barrel. The core bit is larger in diameter than the hole saw, and when the core bit is in its extended position, the hole saw is enclosed within the barrel, as illustrated in FIG. 1.

Core bit 13 is mounted on shaft 11 by means of a mounting block 36 which is formed to include an axially extending bore 37 having a contour corresponding to the non-circular cross section of the upper and lower portions of the shaft. In the embodiment illustrated, bore 37 is square, and block 36 is slidably mounted on the shaft and constrained for rotation with the shaft. Core bit 13 is mounted on the lower portion of the mounting block and rigidly secured thereto by set screws 38, only one of which is shown in the drawings.

Resilient means is provided for urging core bit 13 toward its retracted position. As illustrated, this means comprises a compressive coil spring 39 constrained between the base of hole saw 12 and the lower end of mounting block 36.

Means is provided for releasably locking the core bit in its extended position. This means comprises a lock ring 41 which is provided with an axially extending opening 42 having a contour corresponding to the noncircular cross. section of the upper and lower portions of shaft 11. In the embodiment illustrated, this opening is square. Radial pins 43 are mounted in the skirt of the lock ring, and they extend into circumferential slots 44 which are formed in the outer surface of block 36. The pins are pressed into openings in the lock ring, and they cooperate with the slots to permit limited rotative movement of the lock ring relative to the core bit while constraining them together axially. 7

When the core bit is in its extended position, as illustrated in FIG. I, lock ring 41 is aligned with circular portion 110 of shaft 11. When so aligned, the lock ring is movable between first and second rotative positions which are determined by pins 43 and slots 44. The first rotative position is the locking position illustrated in FIG. 1 wherein the lock ring and core bit are constrained against axial movement by

shaft shoulder

21 and 22. In the second rotative position, the noncircular portions of the shaft, and the lock ring and core bit are free to move axially of the shaft. A resilient coil spring 46 urges the lock ring toward its first or locking position. One end 46a of the spring is anchored to the lock ring, and the other end 4612 is anchored to block 36. Spring 46 rotates the lock ring in the same direction that the drill is normally driven-when in use, namely clockwise as viewed from above in FIG. 1.

An axial flow passage 47 and radial flow passages 48 are formed in shaft 1 1. These flow passages are adapted to communicate with a flow passage in the output shaft of the drilling machine, and they convey lubricating- /cooling fluid to the cutting edge of the core bit.

Operation and use of the drill can be described briefly. It is assumed that the drill has been connected to the output shaft of a suitable drilling machine and that the machine has been positioned to drill holes where a floor tap insert is to be installed. The core bit is moved from its retracted position to its extended position by sliding it down shaft 11 until lock ring 41 is aligned with the circular portion 11c of the shaft. With the lock ring so aligned, spring 46 rotates it to its locking position, locking the core bit in its extended position. As the drilling machine advances the drill. the core bit cuts through the concrete flooring until it reaches the metal cover of the utility passage. The drill is then retracted, and the concrete core is removed from the core bit. Next the core bit is moved to its retracted position by grasping ring 41 to retard the rotation of the ring relative to the shaft and core bit. When the ring is retarded to the point where opening 42 is aligned with the non-circular portions of the shaft, coil spring 39 moves the core bit up relative to the shaft and hole saw to its retracted position. The drill is then advanced again, and the hole saw cuts through the utility passage cover. When this hole is completed, the drill is again retracted, and spring 31 ejects the sheet metal cutout from the hole saw. The drilling machine and drill can then be moved to another location where another floor tap insert is to be installed, and the holes in the concrete and sheet metal are drilled as above.

In the embodiment of FIGS. 1-3, the outside diameter of hole saw 12 is illustrated as being slightly less than the inside diameter of core bit 13. If desired, other sizes of hole saws and core bits can be used, provided that the outside diameter of the hole saw is no greater than the inside diameter of the core bit. As illustrated in FIG. 4, if the diameter of the hole saw is substantially less than the diameter of the core bit, a spacer 49 is utilized to maintain the open end of the core bit centered relative to shaft 11 and the hole saw. This spacer is mounted on threaded boss 26 above the hole saw, and

it has a diameter slightly less than the inside diameter of the core bit.

The embodiment shown in FIGS. 5-7 is similar to the embodiment described previously except that it is provided with a shift mechanism which permits an operator to move the core bit between its extended and retracted positions without touching the rotating bit. The shift mechanism includes a control rod 51 which is spaced apart from and generally parallel to shaft 11. The control rod is joumalled in a guide sleeve 52 which is affixed to the drilling machine motor 53 by screws 54. Clearance holes 56 are provided in the sleeve to facilitate installation of the screws. Thecontrol rod extends above the motor to a convenient height, and a knob 57 is mounted on the upper end of the rod.

-A flexible brake band is disposed adjacent to lock ring 41 and connected at its ends to control rod 51 by pins 62. These pins extend between radially protruding ears 63 affixed to the control rod. The length of the brake band is such that the band normally passes freely around the lock ringand can be tightened against the ring to retard its rotation by rotating the control rod.

A shifting fork 66 is mounted on control rod 51 below brake band 61 for moving core bit 13 between its extended and retracted positions. The shifting fork extends into a groove 67 formed in a race member 68 which is affixed to the barrel of the core bit. The race member is preferably fabricated of a material such as nylon or teflon to minimize friction between the shifting fork and the walls of the groove. The fork is rotatably mounted on the control rod by means of an axially elongated bushing 69 which is rigidly affixed to the shifting fork. A brace 71 provides additional strength at this point. The shifting fork is constrained for axial movement with the control rod by

collars

72 and 73 which are affixed to the rod above and below bushing 69, respectively. 1

The embodiment'of FlGS. 5-7 differs from the embodiment of P165. l-3 with regard to the pins and slots which limit the movement of lock ring 41 relative to core bit 13. In the embodiment of FIGS. 5-7, the lock ring is provided with a pair or arcuate slots 76 through which pins 77 extend. The lower ends of these pins are secured to block 36, and the pins have heads at their upper ends which are wider than the slots. Altematively, if desired, the embodiment of FIGS. 5-7 can be provided with radial pins and circumferential slots similar to. pins 43 and slots 44. If pins and slots of this type are used, the pins should extend no farther than the outer surface of lock ring 41 so that they will not interfere with brake band 61.

Operation and use of the drill shown in FIGS. 5-7 is generally similar to that of the embodiment described previously. ln the embodiment of FIGS. 5-7, however, the operator moves the core bit from its retracted position to its extended position simply by pushing down on control rod 51 until lock ring 41 is aligned with circular shaft portion 116 and coil spring 46 rotates the lock ring to its locking position. To disengage the ring from this position, the operator rotates control rod 51 to tighten the brake band against thelock ring and retard its rotation. When the lock ring is retarded to the point where opening 43 is aligned with the non-circular portions of the shaft, coil spring 39 lifts the core bit toward its retracted position. v

The invention has a number of important features and advantages. It permits holes of different diameters to be drilled successively without changing drills, and it assures accurate alignment of the holes. The core bit can be moved between its extended and retracted positions while the drill is turning, and in one embodiment an operator can move the core bit without touching it and without bending over. This drill makes it possible to install floor tap inserts much faster than was possible with the apparatus and techniques of the prior art.

It is apparent from the foregoing that a new and improved floor tap insert drill has been provided. While only the preferred embodiments have been described herein, as will be apparent to those familiar with the art, certain changes and modifications can be made without departing from the scope of the invention as defined by the following claims.

I claim:

1. In a floor tap insert drill for cutting holes in concrete flooring and in the wall of a utility duct beneath the flooring an axially extending shaft having first and second axially elongated portions of non-circular cross section and a portion of circular cross section intermediate the first and second portions, with a radial shoulder between the first non-circular portion and the circular portion, a circular hole saw affixed to the shaft toward one end thereof, a masonry core bit having a cylindrical barrel and an open cutting end of larger diameter than the hole saw mounted coaxially of the shaft and constrained for rotation therewith, said core bit being movable axially of the shaft between an extended position in which the hole saw is enclosedwithin the barrel of the core bit and a retracted position in which the hole saw is exposed beyond the open end of the core bit, and a lock member carried by the core bit and constrained axially thereto, said lock member being aligned with the circular portion of the shaft when the core bit is in its extended position and when so aligned being movable between first and second rotative positions relative to the core bit and shaft, the first rotative position being a locking. position in which the lock member cooperates with the shoulder on the shaft to retain the core bit in its extended position, the core bit being free to move axially of the shaft when the lock member is in. its second rotative position.

2. The floor tap insert drill of claim 1 wherein the lock member has an axially extending bore having a contour corresponding to the non-circular cross section of the shaft.

3. The floor tap insert drill of claim 1 further including a resilient member disposed within the barrel of the core drill and urging said drill toward its retracted positron.

4. The floor tap insert drill of claim 1 further including a compressive spring member mounted within the hole saw and yieldably extending beyond the cutting edge thereof for ejecting cutouts from the hole saw.

5. The floor tap insert drill of claim 1 further including a resilient member urging the lock member toward its first rotative position.

6. The floor tap insert drill of claim 5 wherein the resilient member urges the lock member to rotate in the direction that the core drill is normally rotated in use.

7. The floor tap insert drill of claim 6 further including means operable remotely of the core bit for shifting said bit between its extended and retracted positions.

8. The floor tap insert drill of claim 7 wherein the means for shifting the core bit comprises a brake member disposed to engage the lock member when actuated, a shifting fork rotatively engaging the core drill and constrained for axial movement therewith, and a control rod spaced from the shaft and connected to the brake member and shifting fork, said control rod being movable between first and second rotative positions for actuating the brake member and between first and second axial positions corresponding to the extended and retracted positions of the core bit.

9. In a drill assembly for successively cutting holes of larger and smaller diameters, an axially extending shaft, a circular hole saw affixed to the shaft toward one end thereof for cutting holes of the smaller diameter, and a cylindrical drill having an open cutting end for cutting holes of the larger diameter mounted coaxially of the shaft and constrained for rotation therewith, said cylindrical drill being movable axially of the shaft between extended and retracted positions relative to the hole saw, whereby the hole saw is enclosed within the cylindrical drill when the cylindrical drill is in its extended position and is exposed beyond the open end of the cylindrical drill when said drill is in its retracted position.

means operable remotely of the cylindrical drill for" shifting said drill between its extended and retracted positions.

13. The drill assembly of claim 9 further including resilient means urging the cylindrical drill toward its retracted position.

Claims

1. In a floor tap insert drill for cutting holes in concrete flooring and in the wall of a utility duct beneath the flooring an axially extending shaft having first and second axially elongated portions of non-circular cross section and a portion of circular cross section intermediate the first and second portions, with a radial shoulder between the first non-circular portion and the circular portion, a circular hole saw affixed to the shaft toward one end thereof, a masonry core bit having a cylindrical barrel and an open cutting end of larger diameter than the hole saw mounted coaxially of the shaft and constrained for rotation therewith, said core bit being movable axially of the shaft between an extended position in which the hole saw is enclosed within the barrel of the core bit and a retracted position in which the hole saw is exposed beyond the open end of the core bit, and a lock member carried by the core bit and constrained axially thereto, said lock member being aligned with the circular portion of the shaft when the core bit is in its extended position and when so aligned being movable between first and second rotative positions relative to the core bit and shaft, the first rotative position being a locking position in which the lock member cooperates with the shoulder on the shaft to retain the core bit in its extended position, the core bit being free to move axially of the shaft when the lock member is in its second rotative position.

3. The floor tap insert drill of claim 1 further including a resilient member disposed within the barrel of the core drill and urging said drill toward its retracted position.

10. The drill assembly of claim 9 in which the cylindrical drill is a masonry core bit.

11. The drill assembly of claim 9 further including means for releasably locking the cylindrical drill in its extended position.

12. The drill assembly of claim 9 further including means operable remotely of the cylindrical drill for shifting said drill between its extended and retracted positions.