HAND-HELD APPARATUS FOR SIDEWAYS DRIVING OF A TOOL

Abstract: Hand tool with an apparatus housing (2), a drive shaft part (10) which is rotatable in the housing, and toolholder part (18) which is mounted pivotably in the housing, is operatively connected to the drive shaft part and has a securing portion (24) projecting from the housing for the purpose of receiving a file, for example. A shaft journal (30) is secured in the drive shaft part (10) and is eccentrically positioned (R) in relation to the centre line (A) of the drive shaft part. The shaft journal (30) supports, on its section (48) outside the drive shaft part, a movement-transmitting member (50') with an outer limit surface (52'). This member is arranged in drive engagement with a recess (54) in the end portion of the toolholder part (18) located inside the apparatus housing (2). In the recess (54) the movement-transmitting member (50') can move transverse to the toolholder part (18), with the outside (52') rolling against adjoining contact surfaces (56, 58) which delimit the recess. The circular eccentric movement of the shaft journal (30) about the centre axis (A) of the drive shaft part (10) imparts to the toolholder part (18), mounted pivotably in the housing (2), a sideways pendulum movement when the drive shaft part is rotating.

Description: Hand-held apparatus for sideways driving of a tool The present invention relates to a hand tool which is designed for motorized operation and which is of the type specified in the precharacterizmg clause of Patent Claim 1. Such a hand tool comprises, in very general terms, an apparatus housing, a drive shaft part wnich is mounted rotatably in the apparatus housing and is designed to be driven by some suitable type of motor, a toolholder part which is mounted pivotably m the apparatus housing, is operativeiy connected to the drive shaft part and has a securing portion projecting from the apparatus housing for a machining tool, for example a file. One end cf a shaft journal is secured in the drive shaft part, the said shaft journal being eccentrically positioned in relation to the geometric axis of rotation or centre line of the drive shaft part. Prior art Hand tools of a similar type are already known from, for example, Swedish Patent Application 9301273-0, US A 2 824 455 anc US A 4 114 270. The hand tool which is αescribed ir. the sa d Swedish patent application has a securing member for a machining tool, preferably a file. This securing member is driven in such a way that it executes a reciprocating working movement in its longitudinal direction, as a result of which the tool secured in the member is caused to execute a reciprocating machining movement in its longitudinal direction. A hand tool of this known type is especially suitable for precision machining of workpiece surfaces in the area of edges, corners, grooves or, mainly, at places where different surfaces of the workpiece join one another at an angle, as a result of which the machining space is limited and/or difficult to get at. However, this known technique always involves a machining direction which is essentially in line dith the longitudinal direction of the hand tool (apparatus) in question. With this known type of hanα tool, however, it is not possible to machine material in the transverse direction of the toolholder part without m this case moving the whole hand tool (apparatus) to and fro in a sideways direction. Obπects of the invention An object of the present invention is to make available a novel type of hand tool which is criven by means of a suitable motor ana with wnich it s possible to macnine material m a direction transverse to the toolnolder part and, consequently, transverse to the machining tool which is held by the toolholder part, and which tool can be, for example, a file suitable for precision machining. Such reciprocating sideways or lateral movement of the tool is required especially for polishing, fine grinding, precision machining, and other types of finish-machining, of surface area_> to which access is difficult, such as in corners, at concave edges, in slots and m recesses. A further object is to make available a nand tool which works with a sideways pendulum movement and whose apparatus housing can have small external transverse dimensions, so that the tool or the apparatus is compact and therefore easy to handle in confined spaces. Another object of the invention is to make available a hand tool which works with a sideways pendulum movement and whose working stroke in the t r ansverse direction of the machining tool (for example the file) is adjustable, or in other words a hand-neld apparatus whose stroke length {sideways pendulum movement) can be adjusted. Disclosure of the invention According to the invention, the abovementioned objects are achieved by virtue of the fact that the hand tool of the type mentioned in the introduction has the features specified in the characterizing clause of Patent Claim 1. Further constructional features, which represent further developments of the invention according to Claim 1, are evident from the dependent claims. What is novel, and what distinguishes the nand tool according to the invention, is that the s .aft journal secured in the drive shaft part has a snaft journal section wnich projects from the drive snaft part and whicn supports a movement-transmitting member with an annular, outer limit surface. This movement- transmitting member is arranged in drive engagement with a recess m the end portion of the toolholder part located inside the apparatus housing. In this recess, the movement-transmitting member can move transverse to the toolholder part, with the outer limit surface rolling against a pair of contact surfaces which delimit the recess. The circling eccentric movement of the eccentrically positioned shaft journal about the axis of rotation of the drive snaft part is generated by the rotation of the drive shaft part and serves to impart to the toolholder part, mounted pivotably in the apparatus housing, a sideways pendulum movement _n a longitudinal plane in the apparatus housing. The movement-transmitting member can be a roll-type bearing, for example a roller bearing or needle bearing, with an outer bearing sleeve, the outside of which then forms the outer limit surface of the member. Alt e rnatively, the movement-transmitting member can be a ball-shaped carrier part which is mounted m a rotatable and axially displaceable manner on the projecting shaft journal section and whose spherically curved outer side then forms the outer limit surface of the member. When the movement-transmitting member is a roll-type bearing, its roll bodies (for example rollers or needles) are arranged between the shaft journal section and the outer bearing sleeve, directly resting against the surface of the shaft journal section and the inside of the bearing sleeve, respectively. The bearing sleeve preferably has a convex curvature in both the circumferential direction and the axial direction. Constructionally, it is possible for the toolholder part to consist, m its area located msiαe the apparatus housing, of an elongate, plate-shaped pendulum portion which is pivotably mounted on a transverse bearing journal in the apparatus housing. This bearing journal is then inserted in a guide body which is arranged in the front part of the apparatus housing and in which there is a longitudinal guide chamber in which the pendulum portion is guided m a pivoting movement. The guide body can in this case expediently consist of two essentially semi-cylindrical guide body parts which are arranged alongside each other, bear against each other, and are mounted in a cylindrical cavity in a front part of the apparatus housing. The guide body parts then have wall surfaces facing each other which are located at a distance from each other and form side walls of the guide chamber for the pendulum portion. A hand tool with adjustable stroke length (i.e. adjustable sideways pendulum swing) can be obtained by means of the shaft journal secured in the drive shaft part being arranged at an acute angle to the axis of rotation of the drive shaft part, the guide body being arranged such that it is axially adjustable in the cylindrical cavity in the front part of the apparatus housing, for example by being screwably received therein. An axial adjustment (screwing) of the guide body in the said cavity then results m a displacement of the ball-shaped carrier part on the inclined shaft journal section, so that the carrier part is forced in towards the geometric axis of rotation of the drive shaft part or is forced outwards therefrom. This forced displacement of the ball-shaped carrier part produces the desired change m the stroke length. Brief description of the figures m the drawings The invention will now be described and explained m more detail hereinbelow with reference to several illustrative embodiments, shown m the drawings, of a hand tool according to the present invention. In the drawings: - Figure 1 shows a longitudinal section through a first embodiment of a hand tool according to the invention; - Figure 2 shows a cross-section along the line II-II in Figure 1; - Figure 3 shows a cross-section along the line III-III m Figure 1; Figure 4 shows a longitudinal section through a second emoodiment of a hand tool according to the invention; - Figure 5 shows a cross-section along the line V-V in Figure 4; and, finally, - Figure 6 shows a cross-section along the line VI-VI in Figure 4. Description of illustrative embodiments Figure 1 shows a longitudinal section through the front part of a hand-held grinding machine designed for motorized operation. The illustrated front part of the hand-held grinding machine is referred to as the hand tool in the present description. In addition to the illustrated front machine part, the complete grinding machine aiso includes a rear machine part which is connected to the said front machine part and which accommodates the drive motor, which may preferably be an electric motor. The machine could alternatively be driven by means of a hydraulic motor or a pneumatic motor. The machine's rear part (not shown here) receiving the motor is intended to be screwed, or connected in some other way, to the .and tool snown here, i.e. the front machine part. The illustrated nand tool comprises an apparatus housing 2 consisting of a front apparatus housing part 4 and of a rear apparatus housing part 6 which is screwed into the rear end of the front apparatus housing part 4 (the left-hand end m Figure 1) anc wnicn represents the housing part that can be connected m turn at the rear to the grinding machine part (not shown here) accommodating the motor. As can be seen from Figure 2 and Figure 3, the apparatus housing 2 is designed as a tubular casing. A drive shaft part 10 is mounted rotatably in the apparatus housing 2 by means of a ball bearing 8, and its left-hand end in the Figure can be connected via a coupling part 12 to the drive motor shaft (not shown here) of the grinding machine. The ball bearing 8 is clamped between, on the one hand, a spacing sleeve 14 inserted in the front apparatus housing part 4, and, on the other hand, the front portion of the rear apparatus housing part 6 which has been screwed into the apparatus housing part 4. The drive shaft part 10 is screwed tight to the inner ring of the ball bearing 8 by means of a nut 16. Also mounted in the front apparatus housing part 4, in a pivotable manner, is a toolholder part 18 which at its rear end is operatively connected to the drive shaft part 10. The toolholder part has a securing portion 24 which projects via an opening 20 in the front end wall 22 of the apparatus housing part 4 and which has an axial bore 26 m which the securing end of a machining tool, such as a file, can be fixed by means of a locking screw (not shown here) which is screwed into the internally threaded bore 28 m the front part of the securing portion 24. One end of a shaft journal 30 is secured in the drive shaft part 10, the said shaft journal 30 being eccentrically positioned, as can be seen, m relation to the axis of rotation or geometric axis of the drive shaft part. In its area located inside the front apparatus housing part 4 of the apparatus housing 2, the toolholder part 18 consists of an elongate, plate- shaped pendulum portion 32 which is pivotably mounted on a transverse bearing journal 34 in the apparatus nousmg. As can be seen from Figure 2, this bearing jour a- 34 is inserted in a guioe oody 36 whicr is arranged m the front apparatus housing part 4 and which has a longitudinal guide chamber 38 in which the pendulum portion 32 is guided such that it can execute a pivoting movement. The guide body 36 is mounted in a cylindrical cavity 39 in the front apparatus housing part 4 and is there axially fixed between the front end wall 22 of the apparatus housing and the annular front end wall of the spacing sleeve 14. The guide body 36 consists of two essentially semi-cylmorical guide oody parts 36' and 36'' which are arranged alongside each other, bear against each other, ano are thus mounted in the cylindrical cavity 39. The guide body parts 36' and 36' ' are in contact with each other at contact surface areas 40 and 42. The guide body parts 36' and 36'' have wall surfaces 44' and 44' ' facing each other which are located at a distance from each other slightly exceeding the thickness of the pendulum portion 32, and which form side walls of the guide chamber 38. We now move on to describe the constructional e n sign of the drive connection between the drive shaft part 10 and the plate-shaped pendulum portion 32 of the toolholder part 18. As can be seen from Figure 1, the shaft journal 30 has a shaft journal section 48 which projects outside the front surface 46 of the drive shaft part 10 and whicn supports a movement- transmitting memoer 50' having an annular outer limit surface 52'. This movement-transmitting member 50' is arranged in operative engagement with a recess 5^- in the end portion of the plate-shaped pendulum portion 32 of the toolholder part 18. Upon rotation of the drive shaft part 10, and consequently upon the circular orbiting movement of the shaft journal 30 aoout the geometric axis A, the movement-transmitting member 50' is movaole in the recess 54 in the direction transverse to the plane of the plate of the pendulum portion 32, i.e. parallel to the axle direction of the bearing journal 34. The reciprocating transverse movement of the movement-transmitting member 50' m the recess 54 - at right angles to the αrawing plane in Figure 1 takes place with the outer limit surface 52' of the member rolling against an upper contact surface 56 and a lower contact surface 58 which constitute the limit surface of the recess 54. The upward and downward pendulum movement of the movement-transmitting member 50', as seen in the drawing plane m Figure 1, is the "useful", active component of the circular orbiting movement cf the shaft journal 30, whicn component is taken up and transferred to the pendulum portion 32 ano results m the desired pendulum movement of the latter about the bearing journal 34. The orbiting eccentric movement of the snaft journal 30 about the geometric axis of rotation A, which movement is generated by the rotation of the drive shaft part 10, thus serves to impart to the toolholder part 18, mounted pivotably in the apparatus housing 2, a sideways pendulum movement (upwards and downwards in Figrre 1) m a longitudinal plane the apparatus housing 2. This pendulum movement thus takes place a plane at right angles to the bearing journal 34, which plane corresponds in Figure 1 to the drawing plane. By means of the tool-holder part 18 thus being set in a reciprocating pendulum movement, the machining tool, for example a file, secured in the bore 26 of the toolholder part 18 is brought into a reciprocating, swinging sideways work movement. In the embodiment of the hand tool according to the invention as illustrated in Figures 1 - 3, the movement-transmitting member 50' consists of a roll- type bearing with an outer bearing sleeve 60 wnose outside then constitutes the outer limit surface 52' of the member. The rci bodies 62 of the roil bearing 50' are arranged between the surface of the shaft journal section 48 and the inside of the bearing sleeve 60. The annular bearing sleeve 60 is designed so that its outside 52' has a convex curvature m the axial direction cf the sleeve, as is shown in Figure 1. In this way, the change in angle between the outside of the bearing sleeve 60 and the contact surfaces 56 and 58 of the recess 54 can take place without play occurring. Reference is now made to the second embodiment of a hand tool according to the invention as illustrated in Figures 4 - 6. This second embodiment differs ir. principle from that illustrated in Figures 1 3 chiefly in that it permits readjustment cr modification of the stroke length of the toolholder part 18, i.e. its maximum pendulum swing about the bearing journal 34. Apart from the constructional features which are required in order to permit an adjustable stroke length, the hand tool according to Figures 4 - 6 is in principle constructed in the same way as the hand tool illustrated in Figures 1 - 3. Those parts of the embodiment according to Figures 4 -6 which correspond directly to the embodiment according to Figures 1 - 3 are therefore provided with the same reference labels as in Figures 1 - 3, and their construction and the way in which they function in relation to one another will not be repeated in conjunction with the description of the embodiment according to Figures 4 - 6. The particular distinguishing feature of the embodiment according to Figures 4 - 6 is that the snaft journal 30 secured in the drive shaft part 10 ι_ m this case mounted in an inclined manner in the drive shaft part 10 so that the journal forms an acute angle α tc the axis of rotation A of the drive shaft part 10. Another particular distinguishing feature of the embodiment according to Figures 4 - 6 is that the movement-transmitting member 50' ' is in this case designed as a ball-shaped carrier part which s mounted a rotatable and axially displaceable manner on the projecting shaft journal section 48 and nose spherically curved outside 64 forms the outer limit surface 52'' of the movement-transmitting member. To obtain an adjustable stroke length for the toolholder part 18, the guide body 36 is in this case arranged in an axially adjustable manner in the cylindrical cavity 39 in the front apparatus housing part 4. The adjustability is this case achieved by means of a form of thread connection m the contact area between the outside of the guide body 36 and the inner wall of the cavity 39. This thread connection includes, for example, as is shown in Figure 4, internal threads 66 on the inner wall of the cavity 39 and, cooperating with these, external threads 68 on the outside of the guide body 36. In this case there is also an annular seal 70 between the guide body 36 and the adjacent wall surface of the cavity 39, which seal 70 affords a suitable friction resistance against undesired screwing movement between the guide body 36 and the apparatus housing part 4. When the stroke length of the toolholder part 18 is desired to be changed, then the guide body 36 is quite simply screwed either some distance axially inwards in the apparatus housing 2 or an axial distance outwards, the result of which is that the movement- transmitting member 50'' designed as a ball-shaped carrier part is displaced some distance inwards (to the left Figure 4) on the shaft journal 30 or some distance outwards thereon, which means that the radial distance R, determining the stroke length, between the geometric axis of rotation A and the longitudinal axis B of the shaft journal 30 is changed to a corresponding extent. In the embodiment according to Figures 1 - 3, this racial distance R is of course unchangeable.

Claims: Patent Claims 1. Hand tool comprising an apparatus housing (2), a drive snaft part (10) which is mounted rotatably m the apparatus housing, a toolholder part (18) whic.i is mounteα pivotably in the apparatus housing, is operatively connected to tr.e drive shaft part ano has a securing portion (24) projecting from the apparatus nousing (2) for a machining tool, one end of a snaft journal v 30) oeing secured m the orive shaft oart (10), the said shaft journal being eccentrically positioned m relation tc tne axis of rotation (A of the drive snaft part, characterized in tnat the snaft journal ^30) has a snaft journal section (48) wmch projects from the orive snaft part (10) ano wnich supports a movement-transmitting member (50', 50'') with an annular, outer limit surface (52', 52''), w.mch member is arranged m drive engagement with a recess (54) in the end portion of the toolholder part (18) located inside the apparatus housing (2), in wnich recess (54) the movement-transmitting member (50', 50' '^ can move transverse to the toolholder part (18), with the outer limit surface (52', 52' ' ' rolling against a pair of contact surfaces (56, 58) wiich delimit the recess, and in that the circling eccentric movement of tne shaft journal (30) about tne axis of rotation (A) of the drive shaft part is generated by the rotation of the drive shaft part (10) and serves to impart to the toolholder part (18), mounted pivotably the apparatus housing (2), a sideways pendulum movement in a longitudinal plane in the apparatus housing (2) . 2. Hand tool according to Claim 1, characterized .n that the movement-transmitting member (50') is a roll-type bearing with an outer bearing sleeve (60) whose outside forms the outer limit surface (52') of the member. 3. Hand tool according to Claim 1, characterized in tnat the movement-transmitting member (5C ') :s a ball-shaped carrier part which is mounted m a rotatable and axially displaceable manner on the projecting shaft journal section (48) and .cse spherically curved outside (64) forms the outer limit surface (52' ') of the member. 4. Hand tool according to Claim 2, characterized m that the roll bodies (62) of the roll-type bearing (50') are arranged oetween the snaft journal section (48) and the outer bearing sleeve (60), directly resting against the surface of the shaft journal section and the inside of tne bearing sleeve (60) . 5. Hand tool according to Claim 4, cnaracterized tnat tne outside of tne Deanng sleeve (60) has a convex curvature in both tne circumferential direction and the axial direction. 6. Hand tool according to any of the preceding claims, characterized in that, in its area located inside the apparatus housing, the toolholder part (18) consists of an elongate, plate-shaped pendulum portion (32) whicn is pivotably mounted on a transverse bearing journal '34) m the apparatus housing, which bearing journal v 34) is inserted in a guide body (36) whicn is arranged m the front part (4) of tne apparatus housing and wnich has a longitudinal guide chamber (38) m which the pendulum portion (32) is guided such that it can execute a pivoting movement. 7. Hand tool according to Claim 6, characterized in that the guide body (36) consists of two essentially semi-cylmdrical guide body parts (36', 36'') which are arranged alongside each other, bear against each other (40, 42), and are mounted in a cylindrical cavity (39) m the front part (4) of the apparatus housing, wnich guide body parts (36', 36'') have wall surfaces (44', 44'') facing each other which are located at a distance from each other and form side walls of the guide chamber (38) for the pendulum portion (32) . 8. Hand tool according to Claim 3, 6 or 7, characterized that the shaft journal (30) secured in the drive shaft part (10) forms an acute angle (α to the axis of rotation (A) of the drive shaft part, and in that the guide body (36) is arranged in an axially adjustable manner in the cylindrical cavity (39) in the front part (4) of the apparatus housing. 9. Hand tool according to Claim 8, characterized in that the guide bocy (36) has an external wall area whicn is provided with protrusions cr tnread portions (68) and which is in screw engagement with a corresponding area of the wall of tne cavity (39) provided witn tnreaαs or protrusions (66), the screwing of the guioe oody in the apparatus housing (2) resulting ir. a change in the stroκe length of the toolnolder part (18) .

Inventors: ERIKSSON ROLF, ERIKSSON, ROLF
Applicants: DENTATUS AB, ERIKSSON ROLF, AB DENTATUS, ERIKSSON, ROLF
Application year: 1996
Main classification: B24B23
IPC codes: B23D67, B23Q5, B24B23, B25F5