US2064889A - Device for converting a rotating motion into a rectilinear reciprocating motion - Google Patents

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Dec. 22, 1936. E DlRlx DEVICE FOR CONVERTING A ROTATING MOTION INTO A RECTILINEAR RECIPROCATING MOTION Filed Sept. 1]., 1955 INVENTOR.

E mil Dirix B An a,

Patented Dec. 22 1936 UNITED STATES PATENT OFFICE DEVICE FOR CONVERTING A ROTATING MOTION INTO A RECTILINEAR RECIPRO- CATING MOTION Emile Dirix, La Calamine, Belgium 3 Claims.

The invention relates to a device for converting a rotating motion into a rectilinear reciprocating motion in the direction of the axis of rotation of the rotating part, with a centre-piece set in motion by the rotating part and two sidepieces joined rigidly together and working in conjunction with the end-faces of the said centrepiece. In earlier devices of this kind important disadvantages were found, the said disadvantages mainly taking the form of violent impacts and vibration and excessively rapid and heavy wear on the most important moving parts. Quite apart from the constant noise that also occurs under such conditions, the use of the device could consequently not be applied after a short while to accurate and fine work.

These disadvantages are completely eliminated by the invention. The essential characteristic of the invention consists of the fact that, owing to the rotating motion of the side-pieces fitted with parallel inner oblique faces and secured against longitudinal displacement, one or more centrepieces, which are mounted loose on one or more eccentrics and lie with parallel oblique faces at their ends entirely on the oblique faces of the side-pieces, move to-and-fro, with the eccentrics, in simultaneous circular and reciprocating motion, the shaft, which is secured against rotation but is capable of moving along its longitudinal axis. The centre-pieces are mounted with the whole of their parallel oblique faces permanently on the corresponding oblique faces of the sidepieces, thus eliminating impacts and ensuring ex tremely small wear. In View of the fact, that, in addition, the side-pieces turn with the larger fly mass, while on the other hand the shaft with the eccentrics performs the reciprocating motion as a considerably smaller fly mass, vibration in the direction of the longitudinal axis, which would disturb the working of the tool used, is in practice as good as eliminated.

In Figs. 1-6 of the drawing the new device is depicted in two different constructions by way of example.

Figs. 1-3 show the device schematically in two longitudinal sections at an angle of 180 to each other and one cross-section for the purpose of explaining the processes of the motion.

Figs. 4 and 5 depict the constructional formation of such a device in longitudinal and crosssection respectively.

Fig. 6 represents a further form of construction of the device.

on the shaft a, secured against rotation but capable of moving along its longitudinal axis, is

secured the eccentric b and on the latter is mounted, in such a way as to be capable of turning, the cylindrical sleeve 0, acting as an eccentric ring, with the parallel oblique faces 0 at its two ends. These oblique faces 0 are in constant contact with the corresponding parallel oblique faces 11 of the two side-pieces d, which have the form of cylindrical bodies and are joined together rigidly by the cylindrical sleeve e. The sleeve 0 is secured against longitudinal displacement on the eccentric b, for example by having a ringshaped projection f of the eccentric engage suitably in a ring-shaped internal groove in the sleeve 0. In this way the sleeve 0 can certainly turn on the eccentric, but in its simultaneous longi- 15 tudinal movement forces the shaft a, which is secured against rotation, to participate in this longitudinal movement. The sleeve e with the side-pieces d secured to it is made to rotate, for example by means of a motor or the like, and is 26 secured against longitudinal displacement in any desired way.

From Figs. 1 and 2 it is possible to see the longitudinal movement of the shaft 0, when the sidepieces turn through 180. The movement is produced by the fact that the centre axis of the sleeve 0 and the axis of rotation of the sidepieces at do not coincide, so that when the sidepieces cl rotate the oblique faces of the sleeve and the side-pieces move over one another. At the 30 same time the sleeve c performs a simultaneous circular and reciprocating movement, thus moving to-and-fro the eccentric b and consequently the shaft a. The axial displacement of the sleeve 0 and of the shaft a is equal to 9 (Fig. 2) and is dependent on the magnitude of the angle of the oblique faces c and (1 As can be seen from the constructional formation as shown in Figs. 4 and 5, the sleeve e is mounted in a tube-shaped housing h, which serves to hold the whole device. The sleeve 0 is secured against longitudinal displacement on the eccentrics b by having the sleeve parts 0 engage between these eccentrics. The cylindrical side-pieces d, which are joined rigidly together by the sleeve e, are mounted, in such a way as to be capable of turning, with their extensions 1' and k in ball bearings I, while they are secured against longitudinal displacement. These ball bearings are fitted in the top and bottom endpieces of the device, and the end-pieces continue as hollow tubes m and n. The shaft a, which is secured against rotation but is capable of moving in the longitudinal direction, is led through suit-- able centre holes in the side-pieces d at either end into the hollow tubes m and n. At the front end the shaft a is fitted with the tool-holder o for the various detachable tools and is also secured against rotation by the said tool-holder. At the lower end a of the shaft a the rotating drive mechanism, for example a motor, is connected up by means of some such device as a flexible connection.

The new device can be used to advantage in all cases where it is desired to obtain from a given rotating motion a reciprocating motion along the axis of the rotating part, thus for example in the case of all tools that have to perform a reciprocating motion. Let us mention here for example surgical saws, fine mechanics saws, files, scrapers, polishing tools, engraving tools, and the like. As the oblique faces 0 and d constantly slide over one another without impact, the wear is extraordinarily small, particularly as by filling with oil the closed housing it is possible to lubricate efficiently all sliding or rotating parts. As the masses of the side-pieces are set at an angle of 180 to each other, the vibrations of the rotating mass are completely compensated. The vibrations and light impacts of the shaft with the eccentrics, this shaft, performing a reciprocating.

motion, being considerably lighter in mass, are completely taken up by the rotating side-pieces, so that the new device, as experience also has shown, works quietly, accurately, without impacts or disturbances and with permanent dependability.

By blocking the shaft a with the eccentric b, the sleeve 0 and the side-pieces d, the device can also be used to transmit a pure rotating motion, when for example it is desired to use the same device for drilling. This blocking can be effected quite simply by clamping together the aforesaid parts, for example by pulling up the shaft a.

In Fig. 6 further form of construction of the device is depicted, in which the member that is to be driven performs a rotating motion with simultaneous axial displacement. The shaft 11 is secured against rotation and also against axial displacement, for example by means of the square 1) and the nut q fitted on the outside. The sidepieces (1, which are joined rigidly together by the sleeve e, are however mounted on the fixed shaft a in such a way as to be capable of displacement and rotation. Owing to the fact that a pressure is now applied alternately in opposite directions on the faces of the side-pieces d, these side-pieces are made to rotate and at the same time to move in the axial direction. This unique form of motion is transmitted by the tube r projecting from the housing to the member that is to be driven. The rotating motion of the sidepieces is in this case brought about by the fact that the axes of rotation of the sleeve 0 and the side-pieces d do not coincide. In the design shown here the pressure is applied to the faces of the side-pieces'by means of pressure media in the form of a gas or liquid which are let into the housing 72, which is sealed on all sides, at differ- ,ent ends alternately, by the piping 8.

If desired it is possible to bring about a reversal of the direction of the motion in the new device by having the shaft a with the eccentrics set into rotating motion and having this rotating motion converted into a reciprocating motion of the side-pieces (Z. The shaft a is then secured against axial displacement, while the side-pieces trics.

(1 are secured against rotation but are capable of displacement along their longitudinal axis. As before, the sleeve 0, the centre-piece, is secured on the eccentric or eccentrics against longitudinal displacement in respect of the said eccen- On the rotation of the shaft a the eccentric b participates in this rotation and therefore moves the sleeve 0 in a circular motion in a direction transverse to the axis of the shaft a. In this way the side-pieces d with the sleeve 6 are moved to-and-fro in the direction of the longitudinal axis of the shaft a, the length of their travel being once again equal to g (as in Figs. 1 and 2).

The invention can also be conveniently applied to various machines, for example in the textile industry and the like, in which it is necessary for the same working part to perform a simultaneous reciprocating and rotating motion. It is then advisable to drive the shaft a, which is not capable of longitudinal displacement, and at the same time the sleeve e, which is capable of longitudinal displacement, at different speeds in the same or opposite directions. By altering the speeds an alteration will accordingly be brought about in the number of to-and-fro movements of the sleeve per unit of time.

I claim:-

1. In a device for converting rotary motion into reciprocating motion, a central non-rotary shaft which is adapted to be driven with a reciprocating movement, an eccentric on said shaft, a cylindrical member revolvably mounted around said eccentric, means for preventing longitudinal movement of said cylindrical member relatively to the eccentric, oblique parallel end faces on said cylindrical member, a rotary nonrcciprocating driving member mounted concentrically about said shaft and oblique parallel faces on said rotary driving member coacting with the oblique end faces of the cylindrical member, rotation of said driving member causing rotation of said cylindrical member around the eccentric on which it is mounted and hence a longitudinal reciprocating motion is imparted to the central non-rotary shaft.

2. In a device for converting rotary motion into reciprocating motion, a central driving rotary non-reciprocating shaft, an eccentric on said shaft, a cylindrical member revolvably mounted around said eccentric, means for preventing longltudinal movement of said cylindrical member relatively to the eccentric, oblique parallel end faces on said cylindrical member, a non-rotary driven member which is adapted to be driven with a reciprocating motion, mounted concentrically about said shaft and oblique parallel faces on said non-rotary reciprocating member coacting with the oblique. end faces of the cylindrical member, rotation of said central driving shaft causing the eccentric to turn in the cylindrical member which imparts a reciprocating motion to the non-r0- tary driven member.

3. A device according to claim 1, having a fixed central shaft, a rotary reciprocating member mounted concentrically about said shaft, and means for acting in the axial direction on the ends of said member, to cause said member to reciprocate and rotate.

EMILE DIRIX.

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