US1745779A - Hole cutter - Google Patents

Description

. "l'fbl 4, 1930. P. A. cARsoN ET A1. 1,745,779

HOLE CUTTER Filed June 22. 1928 INVENTQRs `1 Patented Feb.V 4, y193.)

f UNITED STATESL ,i ,PAUL A. oARSoN, on PITTSBURGH, AND WILLIAM BROAD, oF vBEAVER nALLS,

- PENNSYLVANIA PATENT ori-rca H'oLE CUTTER y Application led .Tune v22,

- provide a hole cutter of the character described, Awhich includes a cutting member directly connected to the ymotor shaft to rotate with the latter, which will facilitate and expedite hole cutting operations, and which embodies a novel supporting element permitting of the engagementk of the work by ythe f device to allow K A high speed cutting operations at-any angle. f

' I Further objects of the invention are to p-rovide'al device ofthe classl stated which'is simple in its construction andarrangement,4

j strong, compact, Vlight in weight, durable and efficient in its use, positive in its action,y conveniently operable, and Vcomparatively inexpensive to manufacture and operate. j

With vthe foregoing and other objects in fview`which will appear as the kdescription proceeds, the inventionfresides in the combiand claimed, it being understood that changes nation andarrangement of parts and in the detalls of construction hereinafter descr1bed in the precise embodiment of the invention herein disclosed can be made within thescope Of the claims hereunto appended ywithout departing from the Vs'pirityof the invention.

Inthe drawing wherein like numeralsof referenceV designate corresponding parts throughout the several v1ews2- f Figure lis a top plan view, partly in sec- Y tion, of a hole cutter constructed in accord- Y bular cutting member; f Referring in detail a'nce'with the invention. y y Figures 2 and 3y are', respectively, Side elevationand front end views of the device.

.Figure l4 isan enlarged end View of the tuto the drawingl representsanelectriciA motor including a motor y to the rear end of the latter.

housing 2 ,and an end plate 3 which is 4secured A motor handle v 4-is fixed to anddepends from the lowerfside of the motor housing-2 and carries the termi- *Inals of the electric current conductors 5.

The 'motor 1 is Slidably mounted on a sup-l "portingframe' 6. The latter comprises three 192s. serial No. 287,434.

cated at 7, 8 and 9. Thefslide rods 7 ,y 8 and 9 are identical in length and-have pointed forward ends 10.

The slide rods 7 and 8 extend through the motor housing 2 adjacent to the periphery of the latter, and are diametrically opposed atrespective sides of the housing 2. Each of the slide rods 7 and 8 further extends through a pair of guide bosses, indicated at 11 and 12. The bosses 11 project forwardly from the front wall of the motor housing 2, and the bosses 12 project rearwardly from the rear end plate 3.

The slide rod 9 extends longitudinally through the tubular motor shaft 13, and is disposed centrally intermediate of the associated slide rods 7 and 8. The rear ends of the slide rods 7, 8 and 9 are ixedly secured in a handle bar 14. The forward end portions of the slide rods 7 and 8 are fixedly joined together by a cross-bar 15. The forward end portions of the slide` rods 7 and 8are threaded as at 16. The cross-bar 15 is secured in position by clamping each end thereof between a pair of nuts 17, which engage each threaded end portion 16, of respective slide rods 7 and 8. f j f The motor shaft 13V projects forwardly yfrom the forward motor bearing 18, and is rigidly connected to the tubular cutting member 19, by a coupling'sleeve 20. The latter overlaps the adjoining ends of the projecting motor shaft 13 and the tubular cutting member 19, and is maintained in the securing position by a pair of set screws, respectively indicated at 21 and 22.

The cutting member 19 is longitudinally aligned with the motor shaft 13 and projects through a centrally disposed aperture 23 formed in the cross-bar 15.l

The forward end of the tubular cutting member 19 is formed with cutting teeth, respectively indicated at 24, 25, 26, 27, 28, 29, 30 and 31. rEhe teeth 24 and 28 are disposed on the mean circumference of the tubular cutting member 19 and are diametrically opposed with respect to each other. The teeth 26 and 30 are disposed inwardly of the circumference of the inner periphery of the cutting member 19 and are diametrically opposed relatively to each other. The teeth 25, 27, 29 and 31 are disposed outwardly of the circumference of the outer periphery of the cutting member 19, and are positioned alternately between the other teeth 24, 26, 28 and 30, respectively.

The relative positions of the teeth 24, 25, 26, 27, 28, 29, 30 andc31, as above described and as clearly illustrated in Figure 4, are provided for the purposel of cutting a groove,

during the hole cutting operation, that will provide ample clearance for the successful that thearrangement be suoli as to provide ample clearance for the operation of the cutting member 19. The clearance provided by the latter entirely eliminates friction' against the outer and inner peripheries of the tubular cutting member 19, and consequently permits of the exceptionally high speed hole cutting operations effected by the direct connection of kthe cutting member 19 with the motor shaft 13.

The cutting :member 19 is formed with a plurality of apertures or slots 32, which are disposed adjacent to the cutting end of the cutting member 19, and provided for the escape or passage of cuttings concomitant with hole cutting operations.

A collar 33, secured by a set screwf34, is

f adjustably mounted on the cutting member 19 and is provided for the purpose of regulating the depths of the holes being cut.

When the motor l is shifted to the rearward position Von the supporting frame 6, as

shown in Figure 2, the forward pointedk ends 10 of the slide 'rods 7, 8 and 9 will project slightly beyond the forward or cutting end of the cutting member 19, the slide rod 9 eX- tending longitudinally through the latter.

In practice, the operation of our improved hole cutter is as follows "Ihe running motor 1'with the associated cutting member 19 is first shifted to the eXtreme rearward position on the supporting frame 6. The projecting pointed endsklO of the slide rods 7 8 and 9 are then forced into the work into which the hole is to be cut.

The operator supports the cutter' by grasping the handle bar 14 with one hand, and shifts the motor 1 forwardly on the supporting frame 6 by his grasp on the motor handle 4 with the other hand, thereby feeding the cutter member 19 into the work and vreadily effecting the hole cutting operation.

In cutting a hole with the tubular cutting member 19, in the manner stated, Vthe corev resulting from the hole-cut, will, of course, be positioned within the cutting member 19. This core will, however, be pushed from the cutting member 19 by the slide rod 9, when the motor 1 is again shifted `rearwardly on the supporting frame 6 'for they subsequent holeV cutting operation. n

'Ihe slide rod 9 not only serves as a medium for dislodging the core from the cutting member 19, but further provides a centering agent for steadying the cutting operation of the latter and generally increasing its eiiciency.

By the adjustment of the collar 33, Yon the cutting member 19, holes of any predetermined depth may be cut. In the event that it is not desired to cut a hole through the work,-` theresulting corewould, of course,` remain in the hole until the same is broken or cut i therefrom; This latter operation may be readily accomplished by any suitableimplen n c ment. I c c It will here be noted that the present inv vention is particularly adaptable for elecy tricians or for other tradesmen whose art callsV l instead of the tubular cutting member 19, as

herein shown and described.y

From the foregoing description, takenin connection with the accompanying drawing, the advantages of the construction and the method of operation will be readily apparent to those skilled in the art to which the inven-lk tion appertains, and while describing the principle of operation ofthe invention together with thedevice providing an embodiment thereof, it isto bey understood that the device shown is merely illustrative, and that various changes in the form, proportions, and details of construction may be resorted to without departing from thev principle or Y sacrificing any of the advantages of the invention as defined in the appended claims.

What we claim is: 1. hole cutter of the character described comprising -a supporting frame, Van electric motor including a shaft shiftably mounted on said supporting frame, a tubular cutter member directly connected with the shaft of saidelectric motor, the forward end of said supporting framek ybeing provided with Vwork engaging elements, said electric motor retractable on said supporting frame to disposeV the forward cutting end of said tubular cutting member rearwardly of said work ent gaging elements, said ksupporting frame includingy a slide rod extending through the said motor shaft and through said tubular cutting member and providing a centering medium for the latter. f

j 2. A hole cutter of the character described comprising a supportingl frame, a driving element including a shaft shiftably mounted on saidsupporting fframe, a tubular cutter member directly connected with said shaft, the forwardend of said supporting frame being provided with work engaging elements,

said driving element being retractable on said supporting frame to dispose the forward cutting end of said tubularV cutter member f rearwardly of said work engaging'elements,

said supporting frame including a slide rod which extends through said tubular cutter member and providing a centering medium u for the latter.

f tures.

In testimony whereof we afifix our signa- PAUL A. CARSON. v WILLIAM BROAD. f

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