US 2155082 A
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Description (OCR text may contain errors)
April 18, 1939 A. G. DECKER 2,155,082
PORTABLE ELECTRIC TOOL AND CASING Filved March 23, 1937 4 Sheets-Sheet l miill April 18, 1939. A. G. DECKER PORTABLE ELECTRIC TOOL AND CASING Filed March 23, 1957 4 Sheets-Sheet 2 w m ,o
April 18, A, G, DECKER 2,155,082
PORTABLE ELECT-RIC TOOL AND CASING Filed March 25, 1937 4 Sheets-Sheet -3 fg f Apri] 18, 1939- A. G, DECKER 2,155,082
PORTABLE ELECTRIC TOOL AND CASING Filed March 25, 1957 4 Sheets-Sheet 4 Poaoood Apr. -1s, 193s UNITED vs'rli'rlss,1 A'lls1s'i'- or-"i-lcl-z :am l 4 roaramamcmcroon Application March 28, im, Serial No.`1312,58
1c Cisano. 'rho invention relatos 'to s poi-tomo powerdriventooloftherotarytype.
Whileadrillhasbeenchosenastheparticular embodiment of the invention to be described,
the invention is adapted to more general application, being capable oi' use in portable powerdriven rotary tools for various Durpe, as tap- P1118. sanding. grinding, and polishing; and while certain features ofthe invention relate particularly to electric tools, other features are capable of more general application.
The object of the invention is to produce a tool of this time which, though capable of general use, is more particularly adapted for use in coniined or restricted spaces where a tool of the usual dimension in the direction of the axis of the bit cannot be introduced, the tool of the invention having greatly increased faculty for use in this way as compared to existing types.
The improved tool to which the invention is applied has the axis of the spindle, the chuck,
' and the bit transversely related to the motor axis and, in accordance with the invention, the tool is so arranged and proportioned that it can beheld in and directed by one hand, which is an important advantage, as there are many instances in which it is difllcult or impossible for the operator to reach with both hands the locality where the work is to be done, and it also frequently occurs that one hand ofthe operator may be otherwise engaged, as in holding other tools, positioning the work, or maintaining theV working position.
The tool of the invention has the further important advantage that it is so arranged that Athe fingers of the hand of the operator, which is guiding and directing the tool, may engage the tool'casing immediately adjacent the shank of the blt, thus effecting a most satisfactory guidance of the tool when supported in one hand, the tool case-or, more particularly, the gear casing at the head-being so arranged that the ning is provided with a nose surrounding the chuck and is further so formed and arranged that the hand may grip the gear casing with the palm of the hand engaging the casing directly back of and in line with the bit and the axis of the chuck, the gear casing being arranged andl of such conguration andso proportioned as to its length that the lingers grip the nose and are free from contact with the rotary chuck.
vthe left'ln Figure 1.
Figure 3 is a fragmentary vview on an enlarged 55 (ci. 11A-c) vwnuotnoromuooofthepoimsripzomo nose whereby the ilngersengagethenoaenear the drill shank is oi.' great importance and advantage, the palm grip is of advantage independently ot the chambered nose. v i
It is a further important accom llshment of the invention that air is supplied thout interruptiontothemotorforcoolingandalsotothe gear casing for cooling the latter, the ventilation being s o arranged that it is not impeded or interfered with by the hand of the operator in the position described, it being an important advantage inthis typeoi' tool that the air draft passes either through or along the outer surface oi' the gear case, thus helping to cool the gear 15 case and avoiding over-heating of the gear case which would be highly dothmental to the onehand operation described. 1
I While 'the drill or other rotary tool of the invention is particularly adapted to be directed and supported by one hand of the operator in the manner already suggested, it can also be supported and directed by the operator usingV one orboth handstograspthemotorcaseorileld case, the axis of which is transverse to the blt and tool spindle. By thus handling the tool it can, for some purposes, be introduced into even smaller spaces than when supported and directed in and by one hand grasping thegear case.
Where the toolisdirectedbygraspingthemotor housing or barrel, two hands are generally necessary to exert suillcient pressure in the direction of the bit axis to secure proper operation of the tool.
It is also of advantage that the gear case and motor case are preferably threaded together, the casing being combined without the use of screws, bolts, and the like. It is of further advantage, contributing to the adaptability of the tool for use in places generally considered inaccessible for work with power tools, that the tool is of a dimension in the direction of the axis of the drill bit which is approximately half the length oi' the previous tools, being approximately three inches whereas the shortest full-powered drill on the market is about seven inches long. The drill of the invention is fully powered, being preferably driven by a small high-speed motor.
In the drawings: v
Figure 1 is a full size side elevation of the tool in the form which is now 'regarded as the preferred `i'orm of the invention.
Figure 2 is an elevation looking'at the tool from scale, the same being broken away to show the interval construction of the tool on a plane of the axis of the motor.
Figure 4 is a section in the plane of the motor and spindle axis.
Figure 5 is a section in the line 5-5 in Figure 4.
Figure 6 is an elevation corresponding to Figure 1 and showing a second form of tool.
Figure 7 is a section on line 1-1 in Figure 6.
Figure 8 is an elevation illustrating a third form of the tool.
Figure 9 is a sectional elevation looking to the left in Figure 8.
Figure 10 is an elevation of the tool of the type shown in Figure 1, showing the manner of grasping the same by the hand in the single-handed control of the tool, half size.
Figure 1 illustrates the operation of the tool in a con ed place, as between the struts of an airplane wing, the drilling and assembling of which is an operation to which the tool is particularly adapted.
Referring to the drawings by numerals, each of which is used to indicate the same or similar parts in the different figures, the construction shown having particular reference to Figures 1, 2, 3, 4 and 5, comprises an electric motor I enclosed in a field case or motor housing 2. This field case or motor housing 2 is closed at one end by a brush and switch housing 3 and at the other end by a gear casing 4. These are rigidly secured in any suitable manner, preferably as hereinafter described. The field case 2, of which the brush housing is an extension, is referred to as the barrel.
In the preferred form of the invention shown. the motor shaft 5, which is preferably in the line of the axis of the casing, has secured thereto and mounted thereon at one end of the motor a Ventilating or cooling fan 6. In the form shown the fan draws air through and around the motor in accordance with the usual practice in motor ventilation, the air being introduced through Ventilating holes I in the field casing 2, passed to the left around the motor and between the armature and field and ejected through and by way of the draft passages 9, 8 in the gear casing and the ring I2. It is of interest in the construction of. the casing that the field or motor casing 2 has a threaded connection at II with a ring I2 which has a central bearing boss I0 which is threaded into the gear casing 4 at I4, the nose I5 which encloses the chuck I6 in a manner to be described being threaded into the gear casing 4 at I1.
The gear casing 4 is provided with bearings I8 and I9 in which a tool spindle 20 is supported at right angles to the motor axis, being driven by pinion 2| on the motor shaft 5, which pinion meshes with the toothed gear 22 mounted on and 'secured to the spindle. The motor shaft is supported in bearings 24 in the ring I2 immediately adjacent the pinion 2| and between the fan 5 and said pinion. It is also of interest that the bearing portion of the ring is connected to the ring proper by radial ribs I2' between which are passages or openings 8' which connect the fan 'chamber 3| to the annular passage 8, all details being subject to variation.
It is an important feature of the invention that the gear casing 4 supporting the spindle 25 at right angles to the motor shaft is constructed of a size and shape to fit within the palm of the hand. In the most highly developed form it is so proportioned and arranged that the fingers extend down over the sides oi the gear casing 4, with their ends bearing on the nose Il of the casing, as best illustrated in Figure l0. This arrangement is best adapted to the direction of the tool when held in one hand.
As seen from the left in Figure 1, and as seen in Figure 2 the gear casing 4 and nose Il together form a pear shaped body, the pear being inverted in both views and having its small end downwardly disposed. The spindle has its axis at right angles to the barrel axis which is also the motor axis and the long axis of the pear shaped body coincides with the spindle axis. 'I'he chuck I4 is in the small end of the pear, and the large end of the pear is of spherical contour about the upper end of the spindle presenting a ball like grip for the hand at the upper end of the spindle and closing the end of the barrel which is of substantially the same radius as the large end of the pear.
The head or gear casing 4 may be described in connection with nose I5 as in the form of an elbow continuous with the front end of the barrel which is treated as horizontal the elbow having a downwardly reducing taper. The convex portion of the turn of the elbow is also regarded as of ball like formation affording a satisfactory palm grip the fingers extending downwardly over the nose which constitutes the reduced end of the taper.
The term zone as used herein has reference to a band shaped area of the nose surface extending around the same at right angles to the nose axis.
In order to illustrate the size and proportions of the casing, this casing with other parts is drawn full size, particularly in Figures l and 2, the gear casing as shown being slightly over three inches from its back surface at 25 in line with the drill axis to the end of the nose at 24, and approximately two and one quarter inches in width from 21 to 2l in Figure 2, it being understood that these dimensions are subject to variation though the dimensions shown are .regarded as most convenient for the average operator, particularly for the one-handed support and control of the tool.
In accordance with the preferred arrangement, the chuck I4 is mounted directly on the lower end of the tool spindle 20 and secured in any suitable manner. It is of particular advantage that the nose I5 be chambered as at 24 to receive and enclose the chuck I4, the lower edge of which may protrude at I4' as illustrated in Figure l, the nose I5 and the gear casing 4 being preferably so proportioned that the protruding portion I4' of the chuck is below the grasp of the fingers, though other features of the invention may be utilized with a different arrangement of the chuck, and
this type of nose has separate utility.
While the tool of the invention is particularly adapted to be grasped and directed by and with one hand of the operator, it is also to be noted that it may be supported and directed by both hands grasping the barrel or the motor casing 2 and that, when thus held, work can be performed under some circumstances in even more confined spaces than when the tool is supported and directed by one hand grasping the gear casing as shown in Figures 10 and 11. I'he ability to support and direct the tool by and with one hand, however, has important advantages as already suggested. Some of the features described are independent of the type of motor. Ihe usual practice provides that the electric motor be ventilated by means of a fan which passes air around the motor, the air being introduced through a series of holes at one end of the casing and exhausted through a corresponding series of holes at the other end of the casing, one set of holes being at the end of the field casing in the vicinity of the gear casing. An important difficulty encountered in the development of the present tool has been due to the fact that in grasping the tool about the gear casing as shown in Figure 6 the latter mentioned set of Ventilating holes is completely or almost covered so that the Ventilating air is cut off from the motor and heating results. To overcome this difficulty the applicant has provided the Ventilating system illustrated in the preferred form in Figures 1 to 5 and in a modified form in Figures 6, 7, 8, and 9. In accordance with this system, the airmay Abe forced or projected by the fan 5 through annularly arranged openings l and 8 which lead from the fan chamber 3| to the annular discharge 32 at the left or forward edge of the ring I2, which ring is an extension of the eld casing 2, which is provided for convenience of construction in this form of the tool, and is omitted or made integral with the eld casing in other forms shown.
The draft openings 5 and 32 extend substantially around the casing circumferentially of the motor shaft providing a passage around the entire periphery of the casing including a slot at the bottom adjacent to nose l 5. To prevent cutting off of the air draft in case the hand, in holding the tool, covers a large portion ofI the peripheral draft opening 32 or any similar draft opening, the surface of the gear casing 4 is grooved or corrugated, the corrugations or grooves 9, in the preferred form shown, extending from the peripheral draft opening 32 ln any suitable arrangement along the surface of the casing and being to best advantage turned from a direction in substantial parallelism with the motor axis at 35 downwardly at 30 s o that they approach the direction of the bit axis and the axis of the tool spindle which is at right angles to the motor axis. 'I'he exact angle of the bit axis and spindle axis is subject to variation if desired, the right angled relation being preferred for convenience in driving. The arrangement of the grooves 9 as shown provides a free discharge for the ven tiiating air under all circumstances of holding, as suggested in Figure 10, and also provides for the cooling of the gear casing, which is an important advantage, particularly in operating the tool when directed and supported by and in one hand with the gear casing gripped as described or in some similar manner. The slotl 33 would not -be covered at any time.
While the fanl 5 has been described as discharging air toward the gear casing, the vacuum thus created serving to draw through the motor air which is introduced at the openings l, a change of the angle of the fan blades which would cause the air to be drawn in through the gear casing 4, passed through the motor and discharged by way of the openings 1, is a non-inventive variation which is contemplated, the direction of the draft being a matter of selection.
Figure 6 shows a modified form of the tool in which the air draft propelled by the fan 40 on the shaft 4I of the motor 42 is released or admitted by way of a series of holes 43 suitably arranged about the gear casing 44. and, further, by way of a slot of any convenient shape at the bottom of the casing. preferably discharging adjacent the nose 45 preferably enclosing the chuck 41 in the manner previously described, it
being further understood that the holes 43 may be of any suitable shape and in any suitable arrangement about the gear casing, the purpose being to avoid closing these holes or the majority of them when the gear casing is gripped by ther hand after the manner illustrated in Figure 10 or in any manner suitable to the supporting and directing of the tool by one hand of the operator. In this connection, slot 45 being of large dimensions in comparison to the holes 43 serves to release a large portion of the air necessary to cool the motor, giving effective cooling when the holes 43 are partially covered, the draft through holes 43 being, however, sufncient to cool the gear casing 44. The holes 43, as shown, are preferably inclined outwardly and forwardly away from the fan, being connected to the fan chamber 45' by a series of corresponding holes 48 drilled in the rear wall 49 of the gear casing, being parallel to -the motor axis or at any suitable angle, it being understood that the arrangement shown is chosen largely for convenience in the formation of the holes by drilling, which contributes to low cost production. It may befurther noted that the air is fed to or from the slot 45 by a plurality of the holes 48 as shown in Figure 7. In this connection, it is to be understood that the draft passages 43, 45, and 45 are subject to considerable variation and that the blades 50 of the fan 4l may be inclined at any suitable angle to pass the air either in the direction shown; i. e., drawing it into the casing by way of the openings 5l, passing it over the motor to the left, and discharging it by way of the holes 43 and the slot 45, or in the opposite direction, so that it is drawn in at 43, 45 and passed to the right through and about the motor and discharged at 5|. While the cooling of the gear casing and motor in this or some equivalent manner 'is of great advantage, the other features of the invention may be utilized without this provision.
'I'he gear connections not shown may be arranged in any\suitable manner, the connections shown in Figure 4 being suitable to the various types of tool illustrated.
In the form of casing shown in Figure 6, the
ring I2 of the previous construction has been` omitted, the casing consisting in this instance of the field or motor casing 53, .constituting the main feature' of the barrel, the brush and switch housing 54, and gear casing 44. The latter, in the most highly developed form, has a n'ose 46, chambered to receive the chuck 41. 'I'he nose -45, as previously described, provides an engagement for the fingers immediately adjacent the bit shank for directing the drill or' other bit I3. as shown in Figure 10.` While this arrangement of nose and chuck is of great advantage, the other features of the invention may be otherwise associated.
The casing members n 44 and 53, have a threaded engagement at as already suggested in connection with the construction previously described, obviating use of screws or bolts in connecting these elements of the casing. this and other details being subject to wide variation.`
Figures 8 and 9 show still another form of the as shown in Figure 9, or this may be referred to as a convenient shape giving an increased cooling area in the casing 64 and increased air draft capacity, the exact shape of the cross section of the openings being subject to variation. It is also to be noted that in -this construction the bottom opening or passage 6| terminates in a downwardly disposed slotted opening 66 which affords a free discharge for a considerable volume of Ventilating air at the bottom of the barrel 6l of the casing, where it is substantially out of reach of the fingers of the operator in holding the tool in the manner shown in Figure i0, so that it is not subject to closing by covering in this way. Further, there is practically no possibility that the holes or outlets 68 from the passages 6I will be covered by the hand in so large a proportion at any one time as to interfere with the cooling of gear casing .64. The construction shown in Figure 8 gives a satisfactory result in the cooling of the motor and inthe cooling of the gear casing so that it can be gripped in the manner described without discomfort or loss of efiiciency on the part of the operator.
'I'he improved portable electric tool construction shown represents an important advance in the production of a portable electric tool of the rotary type for use as a drill, screw-driver, wrench, or for other purposes, and is particularly adapted for use in confined and restricted spaces where a tool of standard dimensions cannot be introduced and also where operation and direction of the tool by one hand of the operator is of advantage, the point of application of the tool being either inaccessible to both hands of the operator'or the other hand being, in many instances, necessary to support the operator in working position, or to hold the work, or the like.
It is further noted that, while the tool is particularly adapted to be held and directed in one hand, it may be directed and operated in still more restricted locations, giving the full benefit of the short dimension of the tool in the direction of the bit axis, by grasping the tool casing with both hands, particularly the barrel thereof, back of the gear casing or head.
It is valso an important advantage contributing to the operation of the tool; i. e., the supporting and direction of the same by one hand, that the rotary chuck is enclosed within the nose of the drill casing which is chambered forthis purpose, giving support for the miler ends or a point of engagement therefor on the tool casing immediately adjacent the shank of the bit. This contributes to more perfect'and accurate direction of the tool by one hand, and protects the fingers from the chuck.
The cooling feature is also of importance in this connection and otherwise in that it provides emcient cooling of both the motor and the gear casing even -though the latter is largely covered by the hand which grasps the tool by the gear casing in the manner described. This feature whereby the gear casing is cooled is almost essential in connection with an electric tool which is to be supported and directed by one hand holding the gear casing in the manner described. with the back of the same in the palm of the hand, whereby heating would interfere seriously with the efliciency of control by the operator.
While the various features described may be used independently, they cooperate in the construction shown and contribute to the common result in the production of a onehand control type of tool which is of widely increased emciency for the purposes described.
It is to be further noted that the tool described is of particular advantage among other uses to which it may be applied in assembling the frames of airplane wings and the like, as shown at 15 in Figure 11, where it is necessary to operate a drill or nut runner between the struts 16 and inside the wings, and hence in localities which are closely restricted as to the dimensions of any tool which can thus be employed. In many instances it can be employed where hand operations were formerly necessary, being adapted to all classes of rotary tool work.
I have thus described a portable rotary electric tool embodying the features of my invention in the preferred and in certain modified forms, the description being specific and in detail in order that the manner of constructing, applying, operating, and using the tool may be understood; however, the specific terms herein are used descriptively rather than in a limiting sense, the scope of the invention being defined in the claims.
What I claim as new and desire to secure by Letters Patent is:
1. A portable, power-driven rotary tool for use in assembling and similar work particularly in confined spaces comprising a barrel and a head at one end of the barrel, said head having spindle bearings and a spindle therein'substantially at right angles to the barrel axis, and a nose at one end of said spindle encircling the spindle and integral with the head, the head being of a size and proportion and being adapted to be enclosed within the palrn of the hand with the finger ends engaging the nose to support and direct the tool, the nose being chambered to receive and contain a chuck on the end of the spindle, the barrel being adapted to contain a motor driving said spindle through angular connections in said head,
and the head being rigidly connected to the casing.
2. A portable power-driven rotary tool for use in assembling and similar work particularly in connned spaces comprising a barrel to serve as a motor casing and a head closing one end of the barrel and rigidly secured thereto, the head having a spindle therein and a nose integral with the head and surrounding the lower end of the spindle and chambered to receive a chuck on said spindle, the axis of the nose and the spindle and chamber being substantially at right angles to the barrel axis, the head being convexly rounded about the upper end of said spindle and proportioned to fit in the palm of the hand with the finger ends engaging the lateral surface of the l nose which is of less diameter than the rounded upper portion of the head, whereby the tool is adapted to be directed and supported by and with one hand of the operator, the fingers being protectedA from contact with the chuck.
3. A portable rotary electric tool for use in assembling and similar work particularly in confined spaces having an electric motor, a field casing therefor, a gear casing rigidly secured to and substantially closing an axial end of the field casing, a spindle in the gear casing substantially at right angles to the motor axis, the gear casing having a smoothly curved convex external surface surrounding and overlying the upper end of the spindle and adapted to nt in the palm of the hand and to be gripped by one hand, whereby the tool is adapted to be directed and supported by one hand of the operator. a chuck on the opposite end of said spindle, the gear casing having a finger grip surrounding the n., or)
spindle, and of less diameter than the said upper convex surface of the gear casing, and rigidly attached thereto, the said grip being adjacent the chuck and adapted to be engaged by the fingers of the hand which encloses the gear casing. i
4. A casing ior a portable rotary electric tool for use in assembling and similar work particularly in conned spaces comprising a barrel adapted to enclose a motor having its axis parallel to the barrel axis and a head closing the front end of the barrel and provided with bearings to support a spindle transverse to the motor axis, the head being in the form of an elbow having a ball like rounded external surface surrounding the upper end of the spindle, the same being shaped and proportioned to serve as a one-hand grip, whereby the tool is adapted to be supported and directed by one hand of the operator, the
barrel having airpassages and the head being' provided with airpassages in its surface con-` tinuoas with the air passages in the barrel for Ventilating the casing and head, the air passages in the head comprising openings spaced -away from the area contacted by the hand in gripping the head.
5. A casing for a portable electric tool for use in assembling and similar work particularly in conilned spaces comprising a barrel adapted to support an electric motor with its axis extending substantially in the direction of the axis of the casing, a gear casing secured to the end of the barrel and adapted to support a spindle substantially at right angles to the motor axis, the gear casing -being o! inverted pear shape and proportioned to be enclosed in the palm of the hand of the operator and having a ball like palmengaging portion enclosing the upper end of the spindle and a rigidly supported iinger-grip portion near the lower end of the spindle, and adapted to be engaged by the lingers of the hand whichencloses the gear casing, the gear casing having Ventilating passages and the barrel having Ventilating passages and means adapted to cooperate therewith to ventilate the gear casing and the motor casing, the Ventilating passages in the gear casing comprising grooves in the surface of said casing traversing a substantial portion of the surface of said casing and connected to the passages in the barrel.
6. A casing for a portableelectric tool for use in assembling and similar work particularly in coniined spaces comprising ak iield casing adapted to support an electric motor with its axis extending substantially in the direction oi' the axis of the casing, a gear casing secured tothe end of the Vfield casing and adapted to support a spindle substantially at right angles to the motor axis, the gear casing being shaped and proportioned to be enclosed in the palm of the hand of the operator and having the palm-engaging portion means adapted to cooperate therewith to ventilate the gear casing and the eld casing, the ventilating passages i in the gear casing comprising grooves-in the surface of said casing disposed in the direction of the axis o! the ileld casing.
7. A casing for a portable electric tool i'or use in assembling and similar work particularly in conilned spaces comprising a field casing adapted to support an electric motor with its axis extending substantially in the direction of the axis of the casing, agear casing secured to the end of the iield casing and adapted to support a spindle substantially at right angles to the motor axis, the gear casing being pear shaped with the axis of the pear coinciding with the axis of the spindle, said gear casing being proportioned tobe enclosed in the palm of the hand of the operator and having the palm-engaging portion which is the large end of said pear shapedcasing smoothly rounded for this purpose, and substantially enclosing the upper end of the spindle and a iinger-grip portion at the lower end of said spindle, said linger grip being rigidly supported on the gear casing, and adapted to be engaged by the fingers of the hand which enclosestlie gear casing, the gear casing having Ventilating passages and the iield casing larly adapted for use in assembling work, and
for operation in coniined spaces, the same having a casing, comprising a barrel in the nature of a field casing for an electric motor, and a head closing one end of the casing, the head being rigidly secured and having spindle bearings and a spindle therein at'right angles to the barrel axis, the head being in the form of an elbow, one arm of which is continuous with the barrel, the elbow having a ball like convex bend, the ball like portion overlying and with the adjacent end portion of the barrel surrounding the upper end of the spindle, the other arm of the elbow having a reducing taper downwardly yfrom said ball like portion, the tapered portion being in the nature of a nose surrounding the lower end of the spindle and being rigidly secured to the head and chambered to contain a chuck on the end of said spindle, the ball like portion being adapted to t in the palm of the hand, the ngers engaging the nose whereby the tool is held and directed in and by one hand.
9. A portable power driven rotary tool for use in assembling and similar work and particularly adapted for operation in conned spaces, the same comprising a barrel having a motor therein and a head rigidly secured to the barrel at one end, said head having spindle bearings and a spindle therein transverse to the barrel axis and a nose at the lower end of said spindle encircling the spindle and rigidly supported relatively to the barrel, the head being of rounded ball-like shape about the upper end of the spindle and of a size 'and proportions adapted to be enclosed within the palm of the hand with he iinger ends extendingl over and engaging the nose to support and direct the bit, the nose being chambered to receive and enclose a chuck on the lower end of said spindle whereby thev fingers are protected from contact with the chuck` as it rotates and the motor having a driving connection with said spindle. Y
10. A portable power driven rotary tool for use in assembling and similar work and particularly adapted ior operation in confined spaces, the
same comprising a barrel having a motor therein and a shaft driven by the motor, a head rigidly supported on the barrel, said head having spindle bearings and a spindle therein transverse to said shaft, which has a. driving connection to said engaging the nose to support and direct the bit, spindle, a, nose at the lower end of said spindle the nose being chambered to receive and enclose encircling the Spindle and rigidly SUDIJOlted, the a chuck on the end of said spindle whereby the head being 0f rOuIlded ball-like Shape about the ngers are protectd from contact with the chuck upper end of the spindle and of size and proas it rotates.
portions adapted to be enclosed Within the palm of the hand with the fingers extending over and ALONZO GAILOWAY DECKER.