US3791034A

US3791034A - Hole punching tool

Info

Publication number: US3791034A
Application number: US00237451A
Authority: US
Inventors: C Carver
Original assignee: Individual
Current assignee: Individual
Priority date: 1972-03-23
Filing date: 1972-03-23
Publication date: 1974-02-12
Anticipated expiration: 1991-02-12

Abstract

A tool for forming pilot holes disposed accurately in a utility passage cover or the like through a layer of flooring. A circle saw uses the pilot holes to cut larger holes through the utility passage cover via an opening formed through a layer of flooring material overlying the utility passage. The tool comprises an elongate staff terminating in a punch portion at one end thereof. An anvil element is carried by the staff at one end and a hammer element is carried by and movable along the staff into and out of engagement with the anvil element for striking blows thereagainst to drive the punch. Guide means carried about the punch portion engage the side walls of the opening to accurately position the punch. The punch element moves freely through the guide during driving of the punch.

Description

ited States atent @arver HOLE PUNCHING TOOL Primary Examiner-Jamcs L. Jones. Jr. Assistant ExaminerJ. C. Peters [76] Inventor gg'gizx f i i i g 52 5; Attorney, Agent, or Firm-Flehr, l-lohbach, Test, Al-

britton & Herbert [22] Filed: Mar. 23, 1972 [21] Appl. No.: 237,451 [57] ABSTRACT A tool for forming pilot holes disposed accurately in a [52] U.S. Cl. 30/367 tflit a a ver the like through a layer of [51 lillll. Cl B26 1/24 flooring A circle saw uses the pilot holes to cut larger [58] Field of Search 30/277, 367, 368, 358; holes th h the utility passage cover via an opening 8 /5 173/91 formed through a layer of flooring material overlying the utility passage. The tool comprises an elongate References Cited staff terminating in a punch portion at one end UNITED STATES PATENTS thereof. An anvil element is carried by the staff at one 2,787,179 4/1957 Warner 30/367 x end and a hammer element is carried by and movable 3,039,467 6/1962 Stone 30/367 x along the Staff into and out of engagement with the 722,559 3/1'903 Bond 30/368 X anvil element for striking blows thereagainst to drive 2,795,052 6/1957 Felenchak.... 30/368 X the punch. Guide means carried about the punch por- 54,585 7/1956 Green 30/277 tion engage the side walls of the opening to accurately 3,036,482 5/1962 Kenworthy 30/277 X ition the unch The punch element moves freely through the guide during driving of the punch.

10 Claims, 5 Drawing Figures Patented Feb. 12, 1974.

nous PUNCHING TOOL BACKGROUND OF THE INVENTION This invention pertains to a hole punching tool for driving or punching holes into the bottom of a cylindrical or other passageway or opening and is particularly useful in the punching of pilot holes for circle saws in making access into utility passages or ducts employed in building construction.

A primary use of the hole punching tool as described herein pertains to the application wherein a utility passage is located beneath a layer of concrete in a building construction.

Generally, in new construction, utility passageways are formed in a building and then embedded or submerged beneath a layer of flooring material, such as concrete. Later, when the floor plan is known and the location of all of the utility outlets is determined, circular holes are cut by circle saws through the concrete flooring down to the metal cover of the utility passageway. Subsequently, using a circle saw, a circular opening is formed through the cover in a manner whereby the diameter of the hole through the metal cover is slightly smaller than the hole formed through the concrete so as to provide a lip which is useful in retaining certain types of utility outlet liners or fixtures which must be positioned or driven axially, into the concrete hole to engage the lip surrounding the hole formed through the metal cover.

In the construction of a new building, great numbers of these utility openings must be provided even though they are not all immediately used in order to provide great flexibility in determining a floor plan for the office or other space to be located in the building.

It is readily evident that, if the circular lip as above described is not exactly concentric with the cylindrical opening formed through the concrete, it will not be possible to properly seat certain of the more popular types of sleeves which fit coaxially within the opening and depend upon proper inter engagement between the lip and a groove formed in the exterior of and about the lower end of the inserted sleeve fixture;

Accordingly, there is a substantial need for quickly forming a pilot hole located dead center, or otherwise accurately positioned, of a utility outlet opening. In this manner, a circle saw can be employed, guided by the pilot hole, to provide acoaxially aligned hole through the top of the utility passage.

SUMMARY OF THE INVENTION AND OBJECTS In general, there has been provided a punch, an anvil portion carried by the punch to be struck a sharp blow for advancing the punch, a guide plate encircling the punch and having a lateral expanse corresponding substantially to the lateral expanse of the hole formed through flooring, for example, and thereby serving to guide the punch centrally of the hole. Resilient means carried between the upper end of the punch and the guide plateserves to eject the punch axially along the opening through which it is positioned and after it has been struck by a hammer.

In general, it is an object of the present invention to provide an improved hole forming tool foraccurately forming pilot holes in a utility passage cover or the like via an opening formed through a layer of flooring or other material overlying the utility cover.

It is another object of the present invention to provide a tool of the kind described above incorporating resilient means for ejecting the punch element from the access hole formed through the flooring material after each blow is struck against the punch element and preferably in a substantially straight line.

The foregoing and other objects of the invention will become more readily evident from the following detailed description of preferred embodiments when considered in conjunction with the accompanying drawmgs.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is an elevation centerline section view showing the invention;

FIG. 2 is a front elevation view according to the invention;

FIG. 3 is an elevation view partly in centerline section according to another embodiment of the invention;

FIG. 4 is an elevation view of the embodiment shown in FIG. 3;

FIG. 5 is an elevation view of another embodiment of the invention;

DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS A hole forming tool 10 which is generally operated in an upright manner to drive or punch holes into metal utility or cable passages 1 1 located beneath the flooring 12 of new construction includes an elongate steel staff 13 formed at its lower end with a re-entrant opening 14 for receiving the threaded upper end of an elongated punch element 16 terminating at its other end in a sharp point.

The exterior of the lower end of staff 13 is threaded and carries thereon a steel or other rigid, metal impact collar 17 in the form of a threaded nut or other element made fast to the lower end of staff 13 by means of welds 18 or other suitable means.

As thus arranged, a hammer element 19 in the form of an elongate sleeve is slidably mounted upon staff 13 for movement between advanced and retracted positions as indicated by arrow 21 whereby the lower end of hammer element 19 may move into and out of engagement with the upper surface of collar 17.

Accordingly, the lower end of hammer element 19 is provided with suitable means such as a nut 22 threaded onto the exterior threads of hammer element 19 and made fast thereto, again simply by means of the welds 23 or other suitable means.

Means have been provided for guiding punch element l6 accurately within a circular opening 24 cut downwardly through the flooring material 12 such as concrete as now to be described.

A circular guide plate 26 having a radial expanse corresponding substantially to the radial expanse of the circular opening 24 includes a center opening 27 through which punch element 16 may advance and retract. Plate 26 is yieldingly supported to float about punch element 16 by means of the three guide rods 28 encircled respectively by helicalsprings 29 captured between plate 26 and a transversely extending support plate 31 carried at the end of staff 13 and formed with openings 32 aligned with similar openings 33 in plate 26. The outer ends of guide rods 28 carry nuts or are formed with a stud head so as to define and adjust the spacing between

plates

26 and 31 in a manner whereby plate 26 will not become dislodged from the end of tool 10.

Plate 31 is tightly held by means of a lock nut 34 to the lower end of tool by tightening lock nut 34 sufficiently to capture plate 31 between lock nut 34 and the bottom of impact collar 17.

In operation, according to the above described embodiment, a suitable punch element 16 is threadedly engaged in readily releasable coupled relationship to the lower end of staff 13 simply by screwing the head thereof into opening 14. When it is desired to punch a starter hole for a circle saw centrally of one of the openings 24, guide plate 26 is first inserted so as to register substantially with the side walls of opening 24 and thereby align the center of opening 24 with punch 16.

Hammer element 19 can then be raised until arrested as, for example, by the nut 35 threaded onto the upper end of staff 13 and then dropped sharply downwardly until the lower end of hammer element 19 strikes impact collar 17. This action serves to transmit a sharp blow to impact collar 17 and, accordingly, to punch 16. This action should be sufficient to drive a starting hole centrally into the opening 24 in the usual circumstance. However, in the event that additional blows are required, it is readily evident that additional blows can be applied without losing registration of the punch with the pilot opening 37 being formed into the top of utility passage 11.

Immediately following impact, springs 19 compress, plate 31 moves downwardly against spring pressure guided by rods 28, and thereafter springs 29 act against plate 31 to urge it quickly upwardly serving to eject punch element 16 outwardly of hole 37 and partially axially outwardly of opening 24 guided in a straight line by the coaxial alignment of

plates

26, 31, each engaging the side wall of opening 24. This action makes it easier on the workman by minimizing the lifting and handling of the tool into and out of the various holes.

According to another embodiment wherein prime marked numbers are employed for those components comparable to those previously described, a conical self-centering helical spring 41 threadedly engages threads formed beneath a continuation of the lower end of impact collar 42 formed on the lower end of staff 36. A guide plate 43 fits snugly within opening 24 and is formed with a coaxial opening 44 therethrough for passing punch element 46 into and out of engagement with the top surface of utility channel 11' of a type wherein a number of electric (or other type) cables may be disposed.

As thus arranged, the lower end of staff 36 includes a tubular downward extension 48 formed with interior threads for engaging a threaded retainer plug 49 having an enlarged head thereon.

Guide plate 43 includes a counterbored portion 50 having a central opening 51 slidably disposed loosely about extension 48. The enlarged head of plug 49 engages the margin of portion 50 around opening 51 so as to couple plate 43 to the lower end of staff 36 while permitting the plate to move between advanced and retracted positions along punch element 46.

The shoulder 47 of impact collar 42 protects the upper convolution or two of spring 41 from being dislodged or otherwise damaged when the tool is generally being handled otherwise than for the purposes as described herein.

The conical spring 41 has a self-centering action which assists the worker in guiding the punch element 46 directly against the top of utility channel 1 1 As before, when hammer element 19' strikes the upper surface of impact collar 42, punch element 46 is driven sharply downwardly and spring 41 immediately compressed. lnstantly, thereafter, the compressed spring 41 serves to eject punch element 46 upwardly in opening 24' in substantially a straight line due to the conical nature of spring 41. Thus, by using the conical spring 41, a reverse thrust is applied to the tool directly upwardly and coaxially of opening 24' during the ejecting movement of punch 46.

Finally, in certain applications under the right circumstances, it may be desirable to eliminate hammer 19 and part of staff 13 above the striking surface of impact collar 42. Thus, as shown in FIG. 5, a number of the self-centering punch elements (without substantial staffs and hammer parts) can be disposed in advance in a number of openings 24" and then a worker can follow with a sledge hammer or other large hammer to strike each of these guided punch assemblies 55 in order to provide the requisite pilot hole in utility channels or the like.

From the foregoing, it will be readily evident that there has been provided an improved tool for simplifying the otherwise somewhat problemmatical locating of the center for a circle saw cut to be made through the top of a utility channel surface or the like.

I claim:

1. A tool for forming pilot holes disposed accurately in a utility passage cover or the like for use by a circle saw where the utility passage cover is accessible via an opening formed through a layer of flooring material overlying said utility passage, said tool comprising an elongate staff terminating in a punch portion at one end thereof, an anvil element carried by said staff at one end, a hammer element mounted exteriorly of the staff and movable along said staff into and out of engagement with said anvil element for striking blows thereagainst to drive said punch portion, and guide means carried about said punch portion for engaging the side walls of said opening and formed to permit said punch portion to move freely therethrough during driving of said punch portion.

2. A tool according to claim 1 including resilient means disposed between said guide means and said one end of the staff for yieldably supporting said guide means from said one end of the staff and serving to resiliently eject said staff and punch portion axially outwardly in said opening after each said blow.

3. A tool according to claim 1 in which said guide means includes a plate and means disposing said plate transversely of the axis of said staff at said one end, the lateral expanse of said plate corresponding substantially to that of said opening, said plate being open coaxially of said punch portion to permit the latter to pass therethrough in response to each blow.

4. A tool according to claim 3 including a second plate extending laterally of said staff and spaced axially of the first plate, elongate guide rods extending between the first named plate and said second plate, said rods being movable through each of the plates, and resilient means disposed between the plates for urging the plates apart, and retaining elements serving to limit said urging so as to maintain the plates disposed about said punch portion.

5. A tool according to claim 1 wherein said punch portion comprises an element discrete from said staff, and further comprising readily attachable means carried by said staff and punch portion in readily coupled relation to attach said portion to the end of said staff.

6. A tool for forming pilot holes disposed accurately in a utility passage cover or the-like for use by a circle saw where the utility passage cover is accessible via an opening formed through a layer of flooring material overlying said utility passage, said tool comprising an elongate staff terminating in a punch portion at one end thereof, an anvil element carried by said staff at said one end, a hammer element mounted externally of the staff and movable along said staff into and out of engagement with said anvil element for striking blows thereagainst to drive said punch, and a guide plate carried about said punch portion and means disposing said guide plate transversely of the axis of said staff at said one end, the lateral expanse of said plate corresponding substantially to that of said opening for engaging and guiding upon the side walls of said opening and including an open portion permitting said punch portion to move freely therethrough during driving of said punch in response to each blow, and resilient means disposed between said guide plate and said one end of the staff said punch element and movable relative to each other in response to application of each blow to said punch element, said plates serving to engage the side walls of said opening for aligning said punch element within said opening, and spring means interposed between said plates for resiliently maintaining said plates apart.

9. A tool for locating a pilot hole for a circle saw in a utility passage cover at the bottom of an opening in a layer of flooring material overlying the utility passage, said tool comprising an axially extending elongated staff, a punch affixed to the staff at one end thereof, an anvil element affixed to the staff toward said end and extending radially outwardly from said staff, a hammer member mounted on the staff and movable axially thereof for striking the anvil element when moved toward the one end of the staff, cooperative means carried by the staff and hammer member for limiting the movement of the hammer member in the direction opposite to the one end, a guide plate having a generally planar axially facing surface for engaging the upper surface of the utility passage cover when placed in the opening in the flooring material and a centrally disposed opening through which the punch can pass, means mounting the guide plate at the one end of the staff with the opening in the plate aligned with the punch, resilient means yieldably urging the plate axially away from the staff, and means limiting the movement of the plate away from the staff.

10. A tool as in claim 9 wherein the resilient means comprises a conically shaped compression spring having a small end affixed to the end of the staff and a large end engaging the guide plate.

Claims

6. A tool for forming pilot holes disposed accurately in a utility passage cover or the like for use by a circle saw where the utility passage cover is accessible via an opening formed through a layer of flooring material overlying said utility passage, said tool comprising an elongate staff terminating in a punch portion at one end thereof, an anvil element carried by said staff at said one end, a hammer element mounted externally of the staff and movable along said staff into and out of engagement with said anvil element for striking blows thereagainst to drive said punch, and a guide plate carried about said punch portion and means disposing said guide plate transversely of the axis of said staff at said one end, the lateral expanse of said plate corresponding substantially to that of said opening for engaging and guiding upon the side walls of said opening and including an open portion permitting said punch portion to move freely therethrough during driving of said punch in response to each blow, and resilient means disposed between said guide plate and said one end of the staff for supporting said guide plate from said one end of the staff and serving to resiliently eject said staff and punch portion axially outwardly In said opening after each said blow.

7. A tool according to claim 6 wherein said resilient means comprises a conically shaped spring interposed between said one end of said staff and said guide plate.

8. A tool according to claim 1 wherein said guide means comprises a pair of spaced plates carried about said punch element and movable relative to each other in response to application of each blow to said punch element, said plates serving to engage the side walls of said opening for aligning said punch element within said opening, and spring means interposed between said plates for resiliently maintaining said plates apart.