US3270593A

US3270593A - Power operated hand tool of the rotary impact type

Info

Publication number: US3270593A
Application number: US319449A
Authority: US
Inventors: Frank A Kaman
Original assignee: Skil Corp
Current assignee: Skil Corp
Priority date: 1963-10-28
Filing date: 1963-10-28
Publication date: 1966-09-06
Anticipated expiration: 1983-09-06
Also published as: DE1503057A1; DE1503057B2; DE1503057C3; NL6412472A; GB1034006A; BE654727A

Description

F. A. KAMAN Se t. 6, i966 POWER OPERATED HAND TOOL OF THE ROTARY IMPACT TYPE Filed Oct. 28, 1963 5 Sheets-Sheet 1 INVENTOR.

FRANK A. ffA/WA/V JTTOKP/VEYS F. A. KAMAN Sept. 6, 1966 POWER OPERATED HAND TOOL OF THE ROTARY IMPACT TYPE Filed 001,. 28, 1963 5 Sheets-Sheet 2 INVENTOR. FRANK A. HAM/4N Sept. 6, 1966 F. A. KAMAN 3,270,593

POWER OPERATED HAND TOOL OF THE ROTARY IMPACT TYPE Filed Oct. 28, 1965 5 SheetsSheet 5 INVENTOR. FRANK A. KAM/Q/V United States Patent 3,270,593 POWER OPERATED HAND TOOL OF THE ROTARY IMPACT TYPE Frank A. Kaman, Prospect Heights, 11]., assignor to Skil Corporation, Chicago, Ill., a corporationof Delaware Filed Oct. 28, 1963, Ser. No. 319,449 2 Claims. (Cl. 81-52.3)

This invention relates to power tools, and more particularly to a new and improved power operated hand tool of the rotary impact type.

The present invention relates to the type of tool ineluding a motor driven impact clutch mechanism which automatically engages and disengages in a rapid manner to deliver -a succession of rotational hammer or impact blows to a driven member for running or loosening nuts, for example. This type of tool, often referred to as an impact wrench, is well known in the art.

In the vast majority of known impact tools, the impact clutch and the rotary motor means for driving the former, are arranged in a tool housing in axial alignment with each other. In other words, in this form of tool the axis of rotation of the impact clutch is coaxial with the axis of rotation of the motor. While this form of tool is satisfactory for operating in many installations, it has the disadvantage of not being able to be manipulated in confined locations because of its relatively long length which results from the impact clutch and motor being in axial alignment with each other.

This disadvantage of this known form of impact wrench has become much more serious in recent years because of the ever increasing complexity of mechanical equipment, such as automobiles, which has resulted in a greater number of threaded fasteners forming a part of this equipment being located in confined locations thereby making these fasteners inaccessible to known forms of power tools unless special attachment devices are used.

Attempts have been made to design impact wrenches of sufficient size for developing the required magnitude of impact blows but yet of a size and shape which will adapt these tools for operating in confined locations. A tool which has been designed with this concept in mind is shown in the Larson et al. Patent 2,581,033. In the Larson et al. tool the axis of rotation of the impact clutch is disposed at a right angle to the axis-of rotation of the rotary motor means. This form of impact wrench has not achieved commercial success and is not on the market at the present time. The main reasons for this lack of commercialsuccess are that a right angle relationship between the respective axes of rotation of the impact clutch and motor means has not achieved the desired space saving objective and that problems have arisen in providing a suitable right angle drive between the impact clutch and motor means without necessitating an increase in the size of the tool for the purpose of accommodating the angular drive means.

Other prior art impact tools have provided angle drive means at the output end of the impact clutch. This type of tool comprises an attachment which includes suitable gearing means for transmitting the rotary impact blows to a nut or the like having its axis of rotation angularly disposed with respect to the axis of rotation of the impact clutch. When using this type of angle attachment, the impact blow is not delivered directly to the nut but is delivered to the latter through the gears of the angle attachment. Transmission of the impact blows through these gears causes a substantial reduction, e.g., 75%, of the impact force, as tests have, proved. Further, the life of the gearsin these, attachments is rather short as the impact blow is absorbed by only one gear tooth or at the most 1.1% of the total teeth in the gear, thereby caus- 3,270,593 Patented Sept. 6, 1966 ice ing breakage of these teeth. Because of these disadvantages, angle attachments for impact tools have not proved to be satisfactory.

Accordingly, it is a primary objective of the present invention to provide a new and improved power operated impact wrench wherein the impact clutch and the rotary motor means therefor are mounted with respect to each other in a unique angular relationship resulting in an impact tool of minimum size in relation to its impact clutch and rotary motor which are of a given size.

Another object of the present invention is the provision of a power tool of the type described wherein the impact clutch and rotary motor means therefor are mounted with respect to each other in a unique angular relationship so as to permit the angular drive between the motor and the impact clutch to be of uncomplicated and compact construction.

Still another object of the present invention is the provision of a tool of the type described having a housing which includes an impact clutch enclosing head portion and a rotary motor enclosing handle portion, the head portion being angularly disposed with respect to the handle portion for maintaining the over-all length of the tool at a minimum without allowing the head portion to project an objectionable distance beyond the laterial extremities of the handle portion.

Even another object of the present invention is the provision of a tool of the type described which includes an impact clutch having a rotary driven member or anvil which is journaled at its output end in one end of the head portion of the tool, the anvil being provided with a tool receiving socket in its output end.

Yet another object of the present invention is the provision of a new and improved socket tool for use with a power tool of the type described, which socket tool is specially adapted for running nuts on stud bolts or the like.

Still another object of the present invention is the provision of a new and improved socket tool for use with a power tool having a rotary driven member which is provided with a tool receiving socket, which socket tool has one end thereof adapted for being detachably received in the tool receiving socket for making a driving engagement between the socket tool and the rotary driven member and the other end thereof adapted for making a driving engagement with a nut or the like, and which socket tool is provided with a central, axially extending, through bore for allowing entry of a stud bolt thereby adapting the socket tool for running a nut a substantial distance along a stud.

These and other objects and advantages of the invention will become apparent from the following specification describing a preferred embodiment of the invention which is illustrated in the accompanying drawings.

In the drawings:

FIG. 1 is a longitudinal central section taken through a power operated hand tool of the rotary impact type constructed according to the present invention;

FIG. 2 is a perspective view of the power tool being held in a human hand;

FIG. 3 is a reduced top plan view of the tool;

FIG. 4 is a side elevational view of the tool showing the same being held in a human hand;

FIG. 5 is a bottom plan vie-w of the tool;

FIG. 6 is an enlarged fragmentary view, partially in section and partially in side elevation, of the power tool and socket tool therefor which forms a part of the present invention;

FIG. 7 is a fragmentary view, partially in section and partially in side elevation, of the socket tool aligned with the tool receiving socket of the rotary driving member of 3 the power tool for being engaged in driving relation with the latter;

FIG. 8 is a side elevational view of the socket tool;

FIG. 9 is an end elevational view of the socket tool as seen from the top thereof; and

FIG. 10 is an end elevational view of the socket tool as seen from the bottom thereof.

By way of introduction, the power operated hand tool of this invention includes a housing having a generally cylindrical, impact clutch enclosing, head portion and an integral, elongated, generally cylindrical, rotary motor enclosing handle portion. The impact clutch extends longitudinally of the cylindrical head portion and has its output end disposed adjacent one end of the head portion of the housing which may be termed the nose of the power tool. The head portion and handle portion of the housing are angularly disposed with respect to each other so that respective central longitudinal axes of these portions intersect and an obtuse angle is defined by the nose of the head portion, the point of intersection of the housing portion axes, and the free end of the handle portion. This angular disposition between the head portion and handle portion of the tool serves to permit the power tool to be of smaller and more comp-act construction for at least two reasons which will become apparent from the following description.

First, taking an impact clutch and a rotary motor of given size and enclosing these components in close confining relation in respective head and handle portions of a housing inclined with respect to each other in the manner described, the over-all length of such a tool may be no greater than a power tool which utilizes a right angle relationship between the axes of rotation of the impact clutch and rotary motor. However, the distance either of the ends of the head portion project beyond lateral extremities of the handle portion will be less because by using the angular relationship according to this invention opposite ends of the head portion project beyond lateral extremities of the handle portion thereby reducing the distance one of the ends of the head portion projects beyond a lateral extremity of the handle portion. In other words, by inclining the head and handle portions of the housing .in the manner according to this invention which brings about projecting respective opposite ends of the head portion beyond the lateral extremities of the handle portion, the distance the nose of the head portion projects from the lateral extremity of the handle portion is much less than would result if, for example, a right angle relationship is employed between the head and handle portions of the power tool.

Ssecondly, by employing the angular relationship of this invention, the resulting power tool may be smaller and more compact since the gearing bet-ween the motor and impact clutch may be of smaller and simpler construction. By using the angular relationship according to the present invention, ordinary bevel gears may be utilized to make up the angular drive between the motor and the impact clutch, and these bevel gears may be of a diameter no greater than the diameters of the rotary motor or cylindrical hammer which constitutes a major portion of the impact clutch. As will become apparent from the following specification, if, for example, a right angular relationship is employed between the impact clutch and rotary motor, at least one of the gears making up this angular drive must be of a diameter greater than the diameter of the hammer of the impact clutch.

This angular constructional feature is of significance as it permits a specific embodiment of the power tool to be constructed so that the nose of the head portion is in general alignment with the knuckles of a human hand grasping the handle portion of the tool, which relationship would not be possible if a right angle drive was used with the sizes of the impact clutch and motor being held constant. Manifestly, this is important when operating the tool in confined locations as it permits the tool to be manipulated in any location which is large enough to permit entry of a human hand. i

The power tool of this invention also includes the provision of providing a socket in the output end of the rotary driven member or anvil forming a part of the impact clutch, which end is journaled in the nose of the head portion of the tool. The provision of this socket in lieu of the conventional driving square which projects from the output end of the impact clutch permits the over-all length of the impact clutch to be reduced thereby resulting in a power tool of reduced and compact size. Further, the invention includes a provision of a socket tool adapted for cooperating with the socket in the rotary driving member of the impact clutch for running nuts on stud bolts in confined locations. j

Now referring to the drawings, the power operated hand tool of this invention, generally designated -10, includes an elongated, generally cylindrical handle portion 12and an integral generally cylindrical'head portion 14'. Handle portion 12 encloses a reversible pneumatic motor 15 which extends longitudinally of the handle portion. Motor '15 includes a cylindrical stator 16 enclosing a plurality of vanes 17 which are mounted on a shaft 18 having one of its ends mounted in a ball bearing assembly 19. The central axis of shaft 18 isco-axial with an axis 20 which defines the longitudinal central axis of housing portion 12. The other end of shaft 18 is supported in a hub portion 22 of a bevel gear 23, which hub portion is rotatably mounted in a ball bearing assembly 24. Shaft 18 includes a splined portion 18a atone of its ends which is fitted in a central splined bore in bevel gear 23 for non-rotatablysecuring the bevel gear on shaft 18.

Handle portion 12 includes a control valve assembly 26 at the free end thereof, which control valve may be of the type disclosed in the application of Carl J. Frenzel, Serial No. 293,501, filed July 8, 1963 now Patent No. 3,202,183. It will be understood that the control valve assembly acts to permit a pressurized fiuid, such as air, to be admitted to motor 15 in either one of two opposite flow paths for bringing about rotation of the motor in either a forward or reverse rotary direction.

Briefly, the control valve assembly includes a fitting 27 threadingly secured in a housing member 28 which is secured to the free end of portion 12 by a plurality of fasteners 28a (FIGS. 3 and 4). Fitting 27 includes a central threaded bore 29 adapted for threading engagement with a suitable fitting on one end of an air conduit, for example. The control valve primarily includes a plunger 31 reciprocal in a selectively rotatable plug 32, which plug may be rotated from the exterior of the power tool by a plate 33 for changing the direction of the flow path of air admitted to motor 15 for changing the direction of rotation of the latter. Plunger 31 is reciprocated for admitting air into motor 15 by means of an operating lever 34 which includes spaced-apart ear plate portions 35 at one of its ends, which portions are 'apertured for receiving a pin 36 thereby adapting the operating lever for swinging or pivoting movement relative to handle portion 12. The operating lever is held in its outer or closed position, indicated in solid lines in FIG. 1, by engagement of the outer end of plunger 31 with the operating member, the plunger being urged outwardly of the tool by means of a coil spring 38. The inner or open position of the operating lever is indicated in phantom lines in FIG. 1. Means operated by a knob 39 are provided for controlling the rate of fluid admitted to motor 15 thereby to control the speed of the latter.

It should be understood that the" power tool of this invention is not to be limited to the particular'motor and control means shown. Any small and compact motor and control means which may beeasily enclosed within elongated handle portion 12 may be employed.

Generally cylindricalhousing head portion 14 encloses in close confining relation'an impact clutch generally designated 40. Impact clutch 40 maybe of the type disclosed in Kaman et al. application, Serial No. 222,868, filed September 11, 1962, now Patent No. 3,228,486. This impact clutch includes a cylindrical hammer 41 adapted for rotation about its central axis which is co-axial with an axis 42 defining a longitudinal central axis of head portion 14. An anvil 43 is rotatably mounted within hammer 41 by roller bearing assemblies 44 and 45 which are spaced along the length of a shank portion 46 of anvil 43. Hammer 41 carries a pair of jaw pins 48 which are slidably mounted in the hammer for movement axially of the latter, the pins being urged in one direction by coil springs 51 for non-interfering relation with diametrically oppositely disposed anvil arms 50. A series of circular cams 53, 54 and S5 operable by means of relative rotation between the anvil and the hammer are provided for periodically projecting pins 48 into a position where they will simultaneously engage arms on the anvil for delivering a sharp rotary impact blow to the latter.

It will be understood that the impact clutch mechanism of itself forms no part of the present invention. Any impact clutch mechanism of compact design may be employed in the powered hand tool of this invention.

Hammer 41 includes a reduced-in-diameter neck portion 58 which mounts a bevel gear 60. Bevel gear 60 is concentrically located on hammer 41 and is non-rotatably secured thereto as by means of a key (not shown), for example. The upper end of the barrel terminates in a hub 61, which hub is of smaller diameter than the diameter of portion 58 and extends axially from the latter.

Hub 61 is rotatably mounted in a ball bearing assembly.

62 which is suitably supported in a circular recess 63 formed in an end housing wall member 64 defining one end of housing portion 14, the housing wall being secured in place by a plurality of fasteners 65.

The end of the anvil defining the output end of the impact clutch is in the form of a cylindrical extension 66 which is journaled in a sleeve '67. Sleeve 67 is nonrotatably mounted in a ring member 68, which ring member is affixed to the nose of cylindrical housing portion 14.

It will be understood that anvil 43 is mounted for rotation within head portion 14 for being given sharp impact blows in rapid succession upon actuation of impact clutch 40, actuation of the impact clutch being brought about by periodic relative rotation between the hammer and anvil in a manner known in the art. Rotation of hammer 41 of the impact clutch results upon rotation of bevel gear 66! which defines the input end of the impact clutch. Rotation of bevel gear 60 is accomplished by rotation of motor 15 by meshing engagement of the teeth of bevel gear 60 with the teeth of bevel gear 23.

As noted in FIG. 1, longitudinal central axes 20 and 42 of

respective housing portions

12 and 14 intersect at a point A which is intermediate the input and output ends of the impact clutch. The angular disposition of these axes with respect to each other is such that an obtuse angle is defined between the nose of head portion 14, point A and the free end of handle portion 12, this angle being indicated as B. Angle B may be in the range of 95 to 155. Preferably, this angle includes 112, this being the angle illustrated in the figures in the drawings.

By further reference to FIG. 1, it will be seen that the cone (indicated by lines 71) containing the pitch surface of bevel gear 69 has its apex at point A. Further, the cone (indicated by lines 72) containing the pitch surface of bevel gear 23 also has its apex at point A. This constructional feature of having the apexes of the cones containing the pitch surfaces of respective bevel gears lying at a common point permits the bevel gears to be of minimum size and yet of ordinary or conventional construction, i.e., larger gears or specially machined bevel gears are not required. It will be noted from FIG. 1 that the diameter of bevel gear 60 at its area of maximum diameter does not exceed the diameter of cylindrical hammer 41. Further, it will be noted that the diameter of bevel gear 23 at its area of maximum diameter does not exceed the diameter of rotary motor 15.

That the angular disposition of respective housing axes 2t) and 42 according to this invention permits bevel gears constituting the angular drive between the motor and impact clutch to be of minimum size and of conventional construction can be understood and appreciated by considering the gearing that would be necessary if axis 42 of head portion 14 was disposed at a right angle with respect to handle portion axis 20, i.e., if angle B was 90. If this relationship was utilized, cylindrical hammer 41 of the impact clutch would be mounted as close as possible to bevel gear 23 in the interest of compact design. It will be readily apparent then that bevel gear 60 would have to be of a diameter greater than the diameter of cylinder 41 to bring about meshing engagement of the teeth of bevel gear 60 with the teeth of bevel gear 23. Increasing of the size or diameter of bevel gear 60 beyond the diameter of hammer 41 is of course objectionable as this would necessitate a power tool of increased over-all size. If on the other hand, this 90 relationship was utilized but bevel gear 60 was of a diameter equal to or less than the diameter of cylindrical hammer 41, bevel gear 23 would have to be of greatly increased size and of unusual shape so as to mesh with gear 60 and yet clear the outer extremities of cylindrical hammer 41.

It should now be apparent that by inclining the impact clutch with respect to the rotary motor in the manner according to the present invention, bevel gears 23 and 60 may be of conventional construction, bevel gear 23 may be of a diameter not greater than the diameter of the motor 15 and bevel gear 16 may be of a diameter not greater than the diameter of cylindrical hammer 41. Manifestly this permits the construction of a power tool of small and compact size. Further, it should be noted that this constructional feature of the tool permits bevel gears 23 and 60 to be of substantially the same diameter for providing an approximate 1:1 drive ratio between the motor and impact clutch, which ratio is desirable in impact tools of the type utilizing an air motor as is known to those skilled in the art.

In obtaining this approximate 1:1 drive ratio, it is preferable to provide a slight difference between the total number of teeth on gear 23 and gear 60 so that the rebound force developed by the impact clutch after every rotary impact blow will be imparted to different pairs of meshing teeth during any series of repeated impact blows. If the same number of teeth are provided on both gears 23 and 60, the same pair or pairs of meshing teeth would be subjected to the rebound forces during any one series of impact blows. A difference of one tooth between the total number of teeth on gears 23 and 6th is sufficient, and this difi'erence or a difference of two or three teeth is intended by the expression an approximate 1:1 drive ratio.

It should also be appreciated that the provision of obtuse angle B between axes 2t) and 42 results in the nose of head portion 14 projecting a shorter distance from the lateral extremity of handle portion 12, i.e., the underside of the handle portion as viewed in FIG. 1, than would be the case if a right angle relationship was employed between axes 20 and 42. Manifestly, if such a right angle relationship was utilized and if the diameter of bevel gear 23 was not increased, bevel gear 60 would be lowered from its position illustrated in FIG. 1 thereby resulting in lowering of the output end of the impact clutch assuming the length of the impact clutch to be constant. It is of course desirable to keep the distance between the underside of handle portion 12 (asillustrated in FIG. 1) and the nose of head portion 14 to a minimum to achieve the design objective of compact construction.

As illustrated in FIGS. 2 and 4 and especially in FIG. 4, according to the construction of the power tool of this invention the nose of head portion 14 is in general alignment with the knuckles of a human hand 75 which is grasping handle portion 12 of the power tool. This feature permits the power tool to be operated in almost any location large enough to accommodate a human hand grasping the tool. In other words, by reason of the angular relationship of axes 20 and 42, the rotary motor means and impact clutch may be enclosed within

respective housing portions

12 and 14 so that the nose of the latter is in general alignment with the knuckles of a human hand and the motor means and impact clutch may be of greater size than would be possible if a right angle relationship was used and the nose of the head portion maintained in alignment with the knuckles of a hand grasping the handle portion of the tool.

The concept of compact design is further eflectuated according to the present invention by providing rotary driven member or anvil 43 with a tool receiving socket 76 in cylindrical portion 66 of the anvil. Tool receiving socket 76, which is preferably hexagonal in shape and terminates in an annular recess 77, is folded or disposed within the portion of the anvil which is journaled in sleeve 66 forming a part of the nose of head portion 14. Tool receiving socket 76 is provided in lieu of the conventional driving square which would project from the nose of the head portion of the power tool.

The present invention also includes a novel socket tool which uniquely cooperates with tool receiving socket 76 for running nuts in confined locations and particularly for running nuts on stud bolts in confined locations.

The socket tool of this invention (FIGS. 6-10), generally designated 80, includes a generally cylindrical body 81. Body 81 is provided at one end 82 thereof with a multisided (preferably hexagonal) exterior shape which corresponds in size and shape to tool receiving socket 76 in anvil 43. Body end 82 includes an exterior annular recess 83 adapted to receive a retainer member such as an O-ring or steel snap-ring 84.

The other or opposite end of body 81 is provided with a multi-sided (preferably hexagonal) socket-opening 85, which socket-opening is adapted to receive a nut or the like for making a driving engagement with the same. Body 81 further includes a central, axially extending through bore 86 which opens at one end thereof into socket-opening 85 and which opens at the other end thereof at body end 82. Body 81 is also provided with an outer knurled circular band 87 which adapts the socket tool to be easily gripped for being inserted in a tool receiving socket or for being removed from a tool receiving socket.

Socket tool 80 is attached to the power tool in a driving relation with the latter by inserting body end 82 into tool receiving socket 76 of anvil 43, retainer member 84 frictionally engages the sides of tool receiving socket 76 for securely holding the socket tool in the tool receiving socket but for permitting the socket tool to be readily detached by hand from the anvil. By reason of the complementary engagement of multi-sided tool receiving socket 76 with multi-sided body end 82, it will be apparent that rotation of the anvil will cause rotation of the socket tool for driving of the latter.

The socket tool of this invention is adapted for running nuts on bolts or driving cap screws, and the socket tool is especially adapted for running nuts on stud bolts in confined locations.

In FIG. 6, tool socket 80 is shown engaged with a nut 90 threadingly engaged on a stud bolt 91 projecting from a workpiece 92. Nut '90 is received in body socket-opening 85 in driven relation with the same. It will be apparent that nut 90 may be run a substantial distance along stud 91, as the stud is permitted to enter tool socket bore 86 duning running of the nut. The feature of providing the socket tool with axially extending bore 86 opening at one end thereof into socket-opening 85 and opening at the other end thereof at body end 82 adapts the socket tool for receiving a portion of a stud as a nut is being run on the same by the socket tool. Accordingly, by the use of socket tool 80 a nut may be run on a stud for a considerable distance along the length of the stud. Heretofore, it has been necessary to employ tools of the end wrench type or special deep sockets to run nuts a considerable distance along a stud bolt. These devices add considerably to the length of the tool and socket combinations and are difficult or impossible to use in confined spaces.

It will also be apparent that socket tool '80 cooperates with the socketed anvil for running a nut on a stud in an environment wherein the stud is disposed in a confined location. This is brought about by the novel cooperation between tool receiving socket 76 and socket tool 80 which results in substantial shortening of the over-all longitudinal length of the head portion 14 and socket tool 80 secured thereto. As is apparent from FIG. 6, since body end 82 is received within socket 76 in the anvil, stud 91 which is allowed to enter bore 86 actually extends into the nose of the power tool itself. In other words, an over-all space saving design concept is made possible by allowing a substantial portion of the stud to enter within the power tool itself as a nut is being run on the stud by the socket tool of this invention. Manifest- 1y, this feature permits the socket tool of this invention and the power tool to run many nuts which are inaccessible when employing prior are socket tools not having special attachments.

It will be apparent that body end 82 maybe shaped or designed to accommodate a particular tool receiving socket of a rotary driving member or anvil. Also, it will be apparent that socket-opening 85 may be provided in sizes and shapes for accommodating a particular nut or the like to be run.

While the invention has been shown in but one form it will be obvious to those skilled in the art that it is not to be so limited, but on the other hand it is susceptible of various changes and modifications without departing from the spirit and scope of the appended claims.

I claim:

1. A power operated hand tool of the rotary impact type comprising, a housing including a handle portion having a longitudinal central axis and a head portion having a longitudinal central axis, rotary motor means in said handle portion extending longitudinally of the latter, a first bevel gear driven by said motor means at one end thereof and being disposed adjacent one end of said handle portion, which bevel gear has its axis of rotation co-axial with said axis of the handle portion and has its maximum diameter no greater than the diameter of the rotary motor means, the apex of the cone containing the pitch surface of said first ibevel gear being disposed outwardly of said one end of the handle portion, rotary impact clutch means including a cylindrical hammer in said head portion extending longitudinally of the latter, which impact clutch means has an input end and an output end, a second bevel gear defining said input end and being disposed adjacent one end of said head portion, which second bevel gear has its axis of rotation co-axial with said axis of the head portion and has its maximum diameter no greater than the diameter of said impact clutch means, the apex of the cone containing the pitch surface of said second bevel gear being disposed intermediate said input and output ends and being coincident with said first mentioned apex, said first and second bevel gears being in meshing engagement with their respective axes of rotation intersecting at the point defined by both of said apexes, the portions of the last mentioned axes between the intersection thereof and respective gears defining an angle in the range of 68, said output end being defined by a driving member having a socket opening at the other end of said head portion and being substantially contained within the latter, said handle portion being in close confining relation with said motor means and first bevel gear and said head portion being in close confining relation with said impact clutch and second bevel gear, said handle portion being elongated along the longitudinal central axis thereof and being of a size such that a substantial portion of the same can be received between the fingers and palm of a human hand, said head portion 'being elongated along the longitudinal central axis thereof and being of a size such that said output end is in general alignment with the extremities of the knuckles of a human hand grasping the tool in the manner set forth.

2. The power tool according to claim 1 wherein said first bevel gear includes a concentric cavity in the face there-of adjacent said impact clutch, and wherein a portion of said cylindrical hammer is received Within said cavity.

References Cited by the Examiner UNITED STATES PATENTS 10 Church 8157 X Gla'baznya 81-57 Sayer 81212.1 X Fosnot. Larson et al. 8152.3 Waterval 81121.1 Coffman et -al. Reynolds 81121 Stumpf 81121 Sindelar 81-523 Schadlich 81-523 MILTON S. MEHR, Examiner.

J. L. Jones, .IR., Assistant Examiner.

Claims

1. A POWER OPERATED HAND TOOL OF THE ROTARY IMPACT TYPE COMPRISING, A HOUSING INCLUDING A HANDLE PORTION HAVING A LONGITUDINAL CENTRAL AXIS AND A HEAD PORTION HAVING A LONGITUDINAL CENTRAL AXIS AND A HEAD PORTION HAVSAID HANDLE PORTION EXTENDING LONGITUDINALLY OF THE LATTER, A FIRST BEVEL GEAR DRIVEN BY SAID MOTOR MEANS AT ONE END THEREOF AND BEING DISPOSED ADJACENT ONE END OF SAID HANDLE PORTION, WHICH BEVEL GEAR HAS ITS AXIS OF ROTATION CO-AXIAL WITH SAID AXIS OF THE HANDLE PORTION AND HAS ITS MAXIMUM DIAMETER NO GREATER THAN THE DIAMETER OF THE ROTARY MOTOR MEANS, THE APEX OF THE CONE CONTAINING THE PITCH SURFACE OF SAID FIRST BEVEL GEAR BEING DISPOSED OUTWARDLY OF SAID ONE END OF THE HANDLE PORTION, ROTARY IMPACT CLUTCH MEANS INCLUDING A CYLINDRICAL HAMMER IN SAID HEAD PORTION EXTENDING LONGITUDINALLY OF THE LATTER, WHICH IMPACT CLUTCH MEANS HAS AN INPUT END AND AN OUTPUT END, A SECOND BEVEL GEAR DEFINING SAID INPUT END AND BEING DISPOSED ADJACENT ONE END OF SAID HEAD PORTION, WHICH SECOND BEVEL GEAR HAS ITS AXIS OF ROTATION CO-AXIAL WITH SAID AXIS OF THE HEAD PORTION AND HAS ITS MAXIMUM DIAMETER NO GREATER THAN THE DIAMETER OF SAID IMPACT CLUTCH MEANS, THE APEX OF THE CONE CONTAINING THE PITCH SURFACE OF SAID SECOND BEVEL GEAR BEING DISPOSED INTERMEDIATE SAID INPUT AND OUTPUT ENDS AND BEING COINCIDENT WITH SAID FIRST MENTIONED APEX, SAID FIRST AND SECOND BEVEL GEARS BEING IN MESHING ENGAGEMENT WITH THEIR RESPECTIVE AXES OF ROTATION INTERSECTING AT THE POINT DEFINED BY BOTH OF SAID APEXES, THE PORTIONS OF THE LAST MENTIONED AXES BETWEEN THE INTERSECTION THEREOF AND RESPECTIVE GEARS DEFINING AN ANGLE IN THE RANGE OF 68*, SAID OUTPUT END BEING DEFINED BY A DRIVING MEMBER HAVING A SOCKET OPENING AT THE OTHER END OF SAID HEAD PORTION AND BEING SUBSTANTIALLY CONTAINED WITHIN THE LATTER, SAID HANDLE PORTION BEING IN CLOSE CONFINING RELATION WITH SAID MOTOR MEANS AND FIRST BEVEL GEAR AND SAID HEAD PORTION BEING IN CLOSE CONFINING RELATION WITH SAID IMPACT CLUTCH AND SECOND BEVEL GEAR, SAID HANDLE PORTION BEING ELONGATED ALONG THE LONGITUDINAL CENTRAL AXIS THEREOF AND BEING OF A SIZE SUCH THAT A SUBSTANTIAL PORTION OF THE SAME CAN BE RECEIVED BETWEEN THE FINGERS AND PALM OF A HUMAN HAND, SAID HEAD PORTION BEING ELONGATED ALONG THE LONGITUDINAL CENTRAL AXIS THEREOF AND BEING OF A SIZE SUCH THAT SAID OUTPUT END IS IN GENERAL ALIGNMENT WITH THE EXTREMITIES OF THE KNUCKLES OF A HUMAN HAND GRASPING THE TOOL IN THE MANNER SET FORTH.