US2690081A

US2690081A - Mechanical movement

Info

Publication number: US2690081A
Application number: US177396A
Authority: US
Inventors: Bjorklund Gustaf Erik; Lindblom Karl Ake
Original assignee: Dentatus AB
Current assignee: Dentatus AB
Priority date: 1949-08-23
Filing date: 1950-08-03
Publication date: 1954-09-28
Anticipated expiration: 1971-09-28
Also published as: GB675449A

Description

Sept 28, 1954 G. E. BJRKLUND ET AL 2,690,081

u MECHANICAL MOVEMENT Filed Aug. 3, 1950 3 Sheets-Sheet l Sept. 28, 1954 Q E BJRKLUND ET AL 2,690,081

MECHANICAL MOVEMENT 5 Sheets-Sheet 2 Filed Aug. 3, 1950 Sept' 28, 1954 G. E. BJRKLUND ET L 2,690,081

MECHANICAL MOVEMENT 5 Sheets-Sheet 5 Filed Aug. I5, 1950 Patented Sept. 28, 1954 2,690,081 MECHANICAL MOVEMENT Gustaf Erik Bjrklund and Karl ke Lindbloni, Stockholm, Sweden, assignors to Aktiebolaget Dentatus, Hagersten, Sweden, a corporation ,of

Sweden Application August 3, 1950, Serial No. 175,396

Claims priority, application Sweden August 23, V1949 `11 Claims. l

The present invention refers to a handtool have ing a rotating part and a part moving .back and forth, the latter part being intended to carry a working tool and receiving its motion from the rotating part through a crank mechanism.

' One object of the invention is to provide Aa handtool of this kind in which the length of the stroke of the part moving back and forth can be varied by changing the eccentricity of the `crank pin. In a preferred form of the invention the crank pin is adjustably arranged on the rotating part in such a way that, when the crank pin is adjusted in order to change the length of the stroke, a counterweight, arranged on the rotating part, is automatically adjusted in such manner that the crank mechanism remains balanced at every length `of the stroke. Of course, the counterweight does not need to be shaped as a separate element but may consist of a flywheel mass forming an integral portion of an engine part included in the rotating part.

Another object of the invention is to provide a handtool of the kind referred to in which the part moving back and forth is arranged to be turned about its axis. Suitably, vthe said part `is arranged to be turned by hand by means offwhich the working tool may be guided so that it closely follows the curvature of the object worked upon. In addition, the part may be arranged to revolve freely, so that, in case of a plane working tool being used, this may automatically adjust itself into the Working plane by being guided by the surface of the object. Further, the yhandtool may be arranged in such a way that the part mOYiIlS back and forth will be mechanically guidedin any angular position.

4Another object of the invention is to provide a handtool of the kind referred to in which the working tool is prevented from being damaged, should it meet a resistance greater than normal.

Finally, an object of the invention is to provide a handtool of the kind referred to .which is particularly easy to handle and handy to work with and therefore Will be suited for a great variety of uses in dilferent ways, especially invling and grinding Work on objects of complicated and varying shape.

Further objects and advantages of the invention will be apparent from the following description in connection with the accompanying drawings in which: e

Fig. 1 is a'verticalsectional view of aform of handtool embodying the invention,

Fig. 2 isa horizontal sectionalview ltaken on the line II-II of Fig. 1,

Fig. 3 is a vertical fragmentary sectional view of .the hahdt991erdint``g$- 1 and 2 applied to anspecial use,`

Fig. 4 is atop plan view of the handtool shown inFig's c.

Fig. 5 is ,a vertical fragmentary sectional View of a modied forinof the handtool according to Figs-land?! Fig. o is a crosssectional View taken on the line VI-VI of Fig. 5a'nd` Fig. "1 is a side elevation showing how the handtool is held .inoperation I n theflg'ures, YI indicates the axle neck or the connecting partthrough .Whichthe tool is coupled to a suitabledriving arrangement, for instance a flexible ,shaftdriven.b5I ,anelectric motor. The axle neck is" carried out as an integral piece off a slide holder 5, `ironrnalled in thev casing 4 of the4 handtool by means of ball bearings 2 and 3.

Eccentrically in thefs'lide' holder', fa revolving slide 6 iscarri'ed whichlcan'be locked in any optional angular position thIOllgl a locking vscrew` `l, threaded in theslide holder.'y Therevolving slide is provided with anaxiallbore, eccentrically positioned, in which a bushing 9, serving as a bearing for a crank v.pi1'1 f,8, yis threaded. At the top, the bore has' an' enlarged portion or cavity I0, serving the doublefpurpseof partly effecting the balancing vand partly effecting the lubrication by forming Aa reservoir for lubricating oil. I n order .to `facil.itatthe 'turning of the slide. its upper portion has la large diameter so as to reach the lnearestfedge ofthe slide holder, and the Slide holder is vprovided AWitha cylindrical cavity, subst antially filled 4by the abOVe-men.- tioned upper portion of the slide. lOn account of the cavity," 'an edge liange `Il is formed on one side of the ,slide holder, the shape o f said fiangebeingobvious rfronlig. 2,. The upper free space of the casing] contains thecrank mechanism which, besides the crank pin, consists ,of a connectingl rod l2, connected with .a toolholder i3 by `means of a hall'and socket joint. The holder travels ,in abushing M, threaded inthe casing,.and is locked througha check nut I5. The space containing the crank mechanism is covered by acap 16," theedge 'portion of which extends intofthe casingandis providedwth an opening I1 through {whichthe connecting rod passes. The head |08 `of the connectingV rod is firmly connectedwiththe Vcrank pin by means of a peg I9 nassiegihrough these Peris! ,The @POF site end ofthe connectingrod is provided with a head zandrassesthrough a ball ll which is located'nvoneendv-of the here of thetube shaped tool holder and rests against a spherical thrust surface, formed therein. At the opposite end of the tool holder, a tool socket 22 is firmly connected with the holder and projects partly in the bore thereof. A helical spring 23 is arranged between the socket 22 and the head 20 of the connecting rod and presses the head against the ball 2| which is thus secured between the head and the spherical thrust surface. 'Ihe socket 22 is provided with a central bore 24 in which a tool may be introduced and secured by means of a clamping screw 25.

It is clear from the construction that the tool holder i3 receives a rectilinear motion back and forth in the bushing I4 and is free to turn about its own centre axis. Therefore, a le arranged in the socket will adjust itself in the working plane. When working in a definite plane, the tool holder may, however, be guided so as to retain perpetually a certain angular yposition during its motion back and forth. For this purpose, a guiding slide 26 is displaceably and rotatably arranged on the bushing I4. The guiding slide has a longitudinal slot 2l in which a projection 28 on the tool socket, in which the clamping screw 25 is threaded, may travel, the guiding slide having been displaced forwardly from its rear position to the guiding position, as shown in Figs. 1 and 2. The guiding slide is locked by means of a clamping screw 29.

If the working tool should meet a resistance greater than normal during its motion back and forth, the spring 23 will be compressed, so that the movement of the tool is limited. By this means, the working tool is prevented from being subjected to strains which would otherwise damage the same.

As the crank pin 8 is firmly connected with the head of the connecting rod and journalled in the slide 6, large bearing surfaces can be attained, without any particular space being required therefore. The lubricating oil existing in the cavity I is supplied to the bearing surface of the crank pin through openings 30 in the bushing 9. As the slide rotates, the oil is thrown outwardly against the side walls of the cavity and is thus prevented from being sucked into the bearing clearance in too large a quantity through the capillary force and after that being thrown away because of the centrifugal force.

The crank pin 8 being eccentrically arranged in the slide 0, which in its turn is eccentrically located in the slide holder, the eccentricity of the rank pin i. e. its distance from the centre of rotation can be varied by turning the slide. On account of the cavity I 0, the slide will have an eccentrically positioned mass equivalent to a certain counterweight which, as the slide is turned, is automatically adjusted in Such a way that its moment of inertia in respect of the axis of rotation is perpetually counterbalancing the moment of inertia of the rotating parts of the crank mechanism in respect of the same axis. 'Ihat this is the case can be understood more easily from the fact that the weight of the material removed on account of the cavity is the same as the weight of the rotating parts of the crank mechanism and that the centre of the cavity lies at the same distance from the axis of rotation as said parts.

By means of an arrangement shown in Figs. 3 and 4, the described handtool may be made to give to the working tool a rotating motion as well as the motion back and forth. For this purpose, the

crank pin is provided at the top with a pivot 3l" on which one end of a bar` 32 is journalled, a

working tool, `for instance in the form of a grinding disk 33 being attached to the other end. The grinding disk is carried by the ball shaped end 35% of a pin 35 fastened to the bar and is thus capable of adjusting itself freely into the working plane. The guiding slide 26 is put in the guiding position, having been turned through degrees from the position shown in Fig. l, so that the slot 2l is directed upwardly and guides the projection 28 in vertica-l position. The bar 32 is carried through a transverse bore 36 in the clamping screw 25 and the cap I6 is turned through 180 degrees, so that an opening 3l is put into a position in which the bar is a'ble to pass freely through the wall of the cap.

As the crank pin rotates, the bar will oscillate about the centre axis of the clamping screw 25 and follows in the main the back and forth motion of the tool holder, so that it will be displaced in the bore of the clamping screw only to a small degree. The working tool thus carries out a circular motion in the working plane.

In Figs. 5 and 6 the part of the handtool moving back and forth consists of a tool holder |0I and a slide |02 connected therewith which travels in a cylinder |03. In the central bore of the tool holder a working tool can be introduced and locked by means of a locking screw |04, which is threaded in a projecting portion |05 of the tool holder. The part moving back and forth receives its motion from a rotating part |00, of the same construction as that shown in Fig. '1, through a crank mechanism, consisting of a connecting rod |01 and a crank pin |08, arranged on the rotating part. One end of the connecting rod is pivoted on the crank pin, the other end being connected with the slide through a universal coupling yielding in the longitudinal direction of the slide. The coupling is formed by an element |09 provided with a spherical surface which rests against a corresponding spherical bottom surface in a central bore of the slide, and a helical spring H0 located in said boring through which a head or flange II2, formed in the end of the connecting rod, is jammed between a piston I|| and the element |09. In order to facilitate the turning of the slide, the head I I2 is provided with a central point which rests against the plane surface of the piston I The cylinder |03 is threaded in the casing II3 of the handtool in such a manner that its centre line forms right angles with the axis of the rotating part and is located in the plane of motion of the crank mechanism. The cylinder is held in a fixed position by means of a locking nut I4. On the outside of the cylinder a revolving slide I i5 is journalled which is widened at its forward end and extends forwardly around the tool holder, the projecting portion |05 of which travels in a longitudinal slot I I6 in the widened portion of the revolving slide. The revolving slide is prevented being displaced in axial direction by its journal portion being located between the locking nut I I4 and an edge lla-nge I'I in the forward end of the cylinder.

In order to make the turning of the revolving slide possible during the work, a control part I I8 is arranged on the revolving slide. The control part has a cylindrical bore through which the revolving slide is carried, and a cut slit IIS extending from the bore, by means of which it can be clamped on the revolving slide by tightening clamping screw |20, the lengthened portion of which serves as a handle I2I. Opposite this handle on the other side of the control part, a

similar handle |22 is arranged coa-'xially in rela tion to the first mentioned handle. The control part may thus be locked in anyoptional angular position relative to the revolving slide and may be displaced axially thereon in released condition. When the control part is placed near the locking nut i |4, it may beheld in a xed angular position by means of a peg |23, driven home into the casing H3, which entersa `slot |24 of they lar position which is determined by the surface worked upon, as the plane tool is carried against and guided by this. Thus the working tool will adjust itself automatically.

If, on the other hand, the control part is clamped on to the revolving slide in such a position that the peg |23 is not located in the slot |24, it will be possible to vary the angular position of the revolving slide by hand during operation and thus also that of the tool holder by actuating the handles |2| and |22. The handtool is then held in the hand in the manner seen in Fig. '7, the index ringer being held on the handle |2| and the middle ringer on the handle |22. The control part may be displaced axially on the revolving slide and be clamped in a position suitable in each individual case,` for the length of the fingers.

The handtool described and shown in the drawings is only to be considered as an example and may be varied in many different ways within the limits stated by the following claims.

What I claim is:

1. A hand tool comprising a casing, a tool holding member mounted for reciprocation in said casing, an axle mounted for rotation in said cas ing on an axis transverse to the direction of reciprocation, a crank pin mounted on said axle for movement toward and away from the axis theerof, a connecting rod operatively connecting said pin and said reciprocating tool holding member, and means operatively connected to said eccentric pin for maintaining a counterbalanced condition of said pin and said tool in different positions of said pin.

2. A hand tool comprising a casing, a slide holder mounted on said casing for rotation about a rst axis, a slide journaled in said slide holder on a second axis eccentric to said rst axis, a crank pin mounted in said slide holder on a third axis eccentric to said second axis, means to retain said slide in an adjusted position relative to said slide holder, a tool holder mounted for reciprocation in said casing in a direction transverse to said rst axis, a connecting rod having one end connected to said crank pin and the other end connected to said tool holder, said slide having a cavity corresponding to the weight of the unbalanced rotating parts.

3. A hand tool comprising a casing, a slide holder mounted on said casing for rotation about a first axis, a slide journalled in said slide holder on a second axis eccentric to said first axis, a crank pin mounted in said slide holder on a third axis eccentric to said second axis, means 6 to retain said slide in an adjusted position rela-f` tive to said slide holder, a tool holder mounted for reciprocation in said casing in a direction transverse to said rst axis, a connecting rod having one end connected to said crank pin and the other end connected to said tool holder, said slide having a cavity coresponding to the weight of the unbalanced rotating parts, said cavity being in communication with the bearing Surfaces of said crank pin for supplying lubrication thereto. Y

4. A hand tool comprising a casing, a slide holder mounted on said casing for rotation about a rst axis, a slide journalled in said slide holder on a second axis eccentric to said first axis, a crank pin mounted in said slide holder on a third axis eccentric to said second axis, means to retain said slide in an adjusted position relative to said slide holder, a tool holder mounted for reciprocation and rotation in said casing in a direction transverse to said first axis, a connecting rod having one end connected to said crank pin and a spherical connection between the opposite end of said connecting rod and said tool holder whereby said tool holder may rotate relative to said connecting rod and said connecting rod may oscillate relative to said tool holder.

5. A handtool comprising a casing, a slide holder mounted on said casing for rotation about a first axis, a slide journalled in said slide holder on a second axis eccentric to said first axis, a crank pin mounted in said slide holder on a third'axis eccentric to said second axis, means to retain said slide in an adjusted position relative to said slide holder, a tool holder mounted for reciprocation in said casing in a direction transverse to said first axis, a connecting rodv having one end connected to said crank pin, the other end of said connecting rod being slidably connected to said tool holder through a swivel joint whereby a tool holder may rotate relative to said connecting rod, and yieldable means in said tool holder for opposing sliding movement of said connecting rod relative to said tool holder, whereby said connecting rod will positively move said tool holder in one direction and yieldably move the same in the opposite direction.

6. A handtool comprising a casing, a slide holder rotatably mounted in said casing on a first axis, a slide rotatably mounted in said slide holder on a second axis eccentric to the said first axis, a bore in said slide having its axis eccentric to said second axis, a bushing mounted in said bore, a crank pin rotatably mounted in said bushing, a tool holder mounted for reciprocation and rotation in said casing, a connecting rod extending between said crank pin and said tool holder for causing reciprocation of said tool holder, said slide being provided with a lubricant retaining and balancing recess surrounding said bushing, said bushing being provided with passages in communication with said recess and the crank pin for the passage of lubricant to the latter.

7. A hand tool comprising a casing, a slide holder mounted on said casing for rotation about a first axis, a slide journalled in said slide holder on a second axis eccentric to said rst axis, a crank pin mounted in said slide holder on a third axis eccentric to said second axis, means to retain said slide in an adjusted position relative to said slide holder, a tool holder mounted for reciprocation and rotation in said casing in a direction transverse to said rst axis, a connecting rod having one end mounted on said crank pin, said tool holder having a bore, a spring positioned in said bore, the other end of said connecting rod extending into said bore, and engageable with said spring, means to retain said other end of said connecting rod in said bore whereby said tool holder is moved yieldably in one direction and positively in the other direction.

8. A hand tool comprising a casing, a crank mounted for rotation in said casing, a tool holder guide extending from said casing in a direction.

able crank mounted for rotation about an axis' in said casing, a bushing extending transversely to said axis, a tool holder mounted for reciprocation and rotation in said bushing, a guiding slide mounted for sliding movement and rotation about said bushing, said guiding slide having a slot formed therein, means for rotating said guiding slide, said tool holder having a projection extendable into said slot, means connecting said crank and said tool holder for reciprocating the latter, and means to secure a tool in said tool holder.

l0. A handtool comprising a casing, a counterbalanced crank mounted for rotation in said casing, a Atool holder mounted for reciprocating in a direction transverse to said crank, an outwardly extending guide mounted on said tool holder, means connecting said crank and tool holder for causing reciprocation of said tool holder, an elongated bar slidably mounted in said outwardly extending guide and having one end pivotally mounted on said crank and the other end projecting outwardly from said casing, and means for supporting a tool at the outer end of said elongated bar.

11. A handtool comprising a casing, an automatically counterbalanced adjustable crank rotatably mounted in said casing, a tool holder mounted in said casing for reciprocation in a direction transverse to said crank, a connecting rod extending from said crank to said tool holder for reciprocating the latter, a bore in said tool holder, a compression spring in said bore, a member having a spherical surface positioned in said bore between said spring and the end of said tool holder adjacent the crank, said tool holder including a surface coacting With said spherical member permitting swivelling movement of said tool holder and connecting rod, said spring normally urging said spherical surfaced member into contact with the adjacent end of the tool holder.

References Cited in the rile of this patent UNITED STATES PATENTS Number Name Date 811,426 Mitchell Jan. 30, 1906 1,813,087 Sandage July 7, 1931 2,274,448 Hoover Feb. 24, 1942 2,331,760 Bitner Oct. 12, 1943 2,503,907 Heer Apr. 11, 1950 2,524,207 Palmer Oct. 3, 1950 2,526,976 Smith Oct. 24, 1950 2,561,344 Cutler July 24, 1951