US2047872A - Grinding and polishing machine - Google Patents

Description

A. F-. KELM GRINDING AND POLISHING MACHINE July 14, 1936.

Filed Feb. 23, 1934 2 Sheets-Sheet l 7/nvemor: if flm July 14, 1936. E 2,047,872

' GRINDING AND POLISHING MACHINE Filed Feb. 25, 1934 2 SheetsSheet 2 Patented July 14, 1936 UNITED STATES PATENT OFFICE 2,047,872 GRINDING AND rousnmc momma Berlin,

Application February-23, 1934, Serial No. 712,623 In Germany February 25, 1933 12 Claims. (Cl. 51-108) This invention relates to grinding and polishing machines and its object is to reproduce entirely by mechanical means operations of polishing which hitherto have only been performed wholly or partly by hand and which on account of the necessity for changing the points of contact-of a freely movable article with a fixed rapidly revolving wheel require skill and are frequently accompanied by danger to the worker.

It is a further object of the invention to provide means which may be advantageously used for polishing light articles and to provide a simple, light and cheap machine for this purpose whereby the .power consumption may be reduced and in addition uniform polishing of the article ensured.-

Machines have been proposed wherein the article has been unidirectionally moved during the polishing operation such movement having been effected either in the direction of the axis of the article or at right angles thereto.

The object of the present invention is attained by moving the article about three axes by mechanical means in such a manner that it is moved during the polishing operation as if by hand the said movement being adapted to the shape of the article.

- The invention is hereinafter more fully described, and is illustrated in the accompanying drawings in which:-

Figure 1 is an elevation of the machine and polishing wheel with driving means.

Figure 2 is a diagrammatical horizontal section through the principal parts of the machine according to Figure I viewed from above.

Figure 3 is an elevation of the mechanism for feeding the article to the polishing wheel.

Figure 4 is a diagram of the revolving head of the machine in one constructional form.

Figure 5 is a diagram of an arm according to Figure 4 with an additional mechanism for moving the article being polished.

Figure 6 is a view of the revolving head, in

which the mechanism according to Figure 5 has been omitted in the case of two arms, and

Figure 7 is a view of a detail of another constructional form.

Figure 8 is a longitudinal sectional view taken through that part of the mechanism represented in'Figure 2.

A is the polishing machine, and opposite stands a motor C driving the polishing wheel B. D is a whole or complete assembly of the feed mechanism and R is the revolving head carrying the articles to be polished.

Mounted on the underframe I of the machine A are two carriages 2 and 3 which are moved in the usual manner by means of handles 4 and 5. The mechanism of the machine A is enclosed in casings 6 and l. Projecting from the front casing 1 is the revolving head R, which is rotated stepwise and presses the articles against the polishing wheel B.

Figure 2 shows the principal parts of the mechanism of the machine. Mounted on a shaft 8, which is driven by any suitable connection with a source of power, not shown, is an eccentric 9, surrounded by a strap connected with a fork ill. The fork I is connected by a sleeve which surrounds a shaft 22 with a cylindrical part II connected to the feed cylinder l2 by a clutch. On

the feed cylinder I 2, which is driven intermittently with a step by step motion, is the revolving head R, in front of which is mounted a stationary rest cam l3 which is fast on the shaft 22, and a working cam M. In Figure 2 the working cam or eccentric I4 is partly concealed by one of the arms l5. Mounted in front of the working eccentric I4 is an eccentric toothed wheel ll (see Figures 2, and 6).

A shaft l8 suitably driven carries a clutch l9, which by means of the spring 20, couples the mechanism D for the feed motion of the revolving head R. Each time the feed mechanism D is coupled, the revolving head is rotated or moved forward by one step. The entire machine can be swung about a vertical axis against the action of the spring F, which insures that the articles being polished shall be held against the polishing wheel B with a yielding force thus simulating the action of the human hand.

Operation of the mechanism according to Figure 2 Shaft 8 rotates with the eccentric 9 which, by means of the forked lever l0, imparts to the elements mounted on the feed cylinder l2, a reciprocating motion allowing the article being treated to reciprocate on the polishing wheel B.

Shaft 18 is coupled to the shaft 8 for example by bevel gears (not shown). When the clutch I9 is engaged, the mechanism D (Figure 3) moves the revolving head R by one step.

The larger toothed wheel 2| of the revolving head feed mechanism is mounted at the outer end of the casing I (Figure 2). Above the shaft 22 is a revolving shaft 23, Fig. 3 carrying a cam disc 24. The cams 25 and 26 of the cam disc 24, on moving past, press upon one arm 21 of a bell crank lever. The other arm 28 of the said bell crank lever has a pin 28:: which engages a cam track 20a connected with the clutch l9 and the toothed wheel 29.

Operation of the feed mechanism D On the rotation of the cam disc 24, the pin 28a of the bell crank lever 21, 28 is lifted out of the cam track 20a, so that the spring 20 throws in the clutch. The toothed wheel 2| now being driven from the shaft l8, rotates the revolving head R by one step until the feed mechanism D is again locked by the bell crank lever 21, 23.

In the diagrammatical illustration according to Figure 4, an eccentric 29 is mounted on the shaft 22. If this eccentric 29 is adjusted the eccentricity of the working eccentric i4 is varied. Mounted behind the working eccentric 1|4 and upon the shaft 22 is the rest cam l3, behind which the revolving head R. rotates stepwise. Pivoted to the revolving head R are for example three arms at. These arms each carry a roller 30 and are each connected to the revolving head R for example by a spring St. The rollers 30 have been omitted in Figure 2. Pivoted to each of the arms 55 is another arm 32, and each of these arms32 carries a roller 33. The arm l5 and the arm 32 are drawn together by a spring 34 until the arm 32bears against a stop 35 or a stationary cam 36 (Figure 4) Operation of the mechanism according to Figure 4 Eccentric M with its shifting eccentric 29 rotate continuously. Behind them the rest cam I3 is stationary. In the recess of the rest cam I3, during polishing only, is situated one of the rollers 30 which is moved radially by the eccentric I 4. The roller 33 thereby runs on the cam 36 and moves the lever 32 tangentially.

If now the revolving head R is actuated, moving by one step, the roller 30 of the lever i5 connected to the revolving head'will be lifted out of the recess of the rest cam l3 and will continue to I run on the rest cam l3.

The eccentric l4 still rotating no longer acts I upon the roller 30 until the said roller 30 on continuing to rotate as the revolving head is fed further again arrives in the recess of the rest cam l3, in the present instance after the revolvin head has been moved stepwise three times.

Figures 5 and 6 illustrate an additional mechanism, whereby the article it (for example a spoon) is rocked about its axis. A toothed wheel i'lis keyed eccentrically on the shaft 22. The arm l5 also carries a toothed wheel 38 which acts like a crank on a lever system. The roller 30 and toothed wheel 38 are preferably mounted upon opposite sides or faces of the lever l5 and preferably supported upon a common shaft. This lever 'system has a connecting rod 39 which engages one arm to of a bell crank lever mounted on the lever l5. The other arm 4| of the said bell crank lever is pivotally connected to a rod 42. Pivoted to the other end of the rod 42 is a screw nut 43 in which is mounted a screw-threaded spindle 44 integral with the rod 45. The rod 45 is rotatably mounted at 46 and 41 and serves as holder for the work-piece i6.

Operation of the mechanism according to Figure 5 The toothed wheel l'l drives the toothed wheel 38. The toothed wheel 38 actuates the lever system 39 to 42,,and also the nut 43, which is secured against rotation, and the spindle 44 with the rod 45 on which is secured the work-piece l3. While it is being machined by the polishing wheel,

the article It is rocked or rotated about its ions!- tudinal axis.

Figure 6 shows an assembly. The cam 36 is secured to the stationary flange 48. In frontof the flange 48 is the revolving head R, and in front of the latter is the eccentric toothed wheel H, which is adjustable by means of the eccentric 29 together with the eccentric l4. The eccentric I4 is situated behind the toothed wheel I1 and behind the eccentric I4 is situated the stationary rest cam l3. The arms l5 are. pivoted at 43 to the revolving head R and are connected to the levers 32 by a joint in which is situated the stop 35 (Figure 4) The arms l5 carry the toothed wheels 38 and the rollers 30. A rod 39 leads from the toothed wheel 38 to the bell crank lever having arms 40, 4i and journalled on the lever l5. Pivoted to the arm 4| is a rod 42 by means of which the nut 43 is reciprocated. The spindle 44 is journalled in the nut 43', and the spindle rotates the rod 45 which is constructed in the form of a workpiece holder.

' Figure 7 shows another constructional example. In this case, a cam 50 is secured to the lever 32 and cooperates with a roller 5|. In this case the roller. 33 and the cam 36 (Figure 4) have been interchanged.

From the foregoing description taken in connection with the drawings it will be seen that, by the machine described, there may be mechanically accomplished grinding and polishing movements and operations very similar to those performed when the articles being treated are applied to therevolving polishing or grinding wheel by the human hand. Thus the holders for the articles have imparted to them, during each polishing operation, three different movements, which for easy reference, especially in the claims hereof, I shall respectively distinguish by single words. These movements are-(1) what I term tangential movements, which are imparted to the operating holder from the revolving eccentric l4 operating upon'the roller 30 carried by the arm I5, which. vibrating said arm, moves the article over the polishing face of the wheel in the direction the length of such article, when supported 'as represented in the drawings; (2) a rocking movement accomplished through the agency of the screw shaft 44 and nut 43, and the associated parts which move said nut, these giving to the article a rocking motion approximately about its major axis or length; and (3) what I term tilting movements performed through the agency of the cam 36 and roller carried by the arm 32 which moves in engagement with the cam, these operating to impart to the object being polished a tilting motion in the direction of its length. While these three movements are taking place, and in the machine illustrated they take place simultaneous- 1y, there 'isgiven to the article a reciprocatory movement across the face of the grinding or polishing wheel, these movements being accomplished through the agency of the eccentric 9 upon the shaft 8. r

The several movements which have been referred to as tangential, rocking and tilting movements, areimparted to the article at each single treatment thereof, and to best accomplish this, the holders for the articles are mounted on a carrier that has imparted to it a step by step motion with periods of rest between the steps, the polishing operations taking place while' the carrier for the article holder, or holders, is at rest, and the periods of rest being suflici'ently prolonged to permit the desired operations to be completed. Several of the operations referred to are repeated again and again many times during each rest period of the holder while the article is applied to the grinding or polishing wheel, such for instance as the reciprocatory motions imparted by the eccentric 9, the tangential movements imparted by the eccentric l4 and the rocking movements imparted by the crank wheel 38 that 'placeto polishing position.

The articles while being polished are held toward the polishing wheel with a yielding force which may be adjusted to suit the particular work being performed, and in this respect, as inthe movements referred to, the machine being described closely simulates the operations of the human hand.

I claim:-

1. In a grinding and/or polishing machine the combination with a revolving wheel, of an intermittently driven revolvable head rotatable stepwise carrying the articles, holders for the individual articles operating against the revolving wheel, means for holding the said head with a yielding force towards the wheel, and means for imparting to the holders while the head is at rest, tangential movements, rocking movements, and tilting movements.

2. The combination stated in claim 1, including as a further element, means for imparting to the article holder reciprocatory movements simultaneously with the other movements imparted thereto.

3. A combination such as stated in claim 1, wherein the means for imparting the tangential movements to an article holder are a lever for carrying the article holder, a driven eccentric and a contact with which the eccentric engages carried by the lever, these operating to vibrate the lever.

4. A combination such asstated in claim 1, wherein the means for imparting the rocking movements to an article holder are a shaft upon which the article holder is supported carrying a screw thread, a movable nut engaging with the said screw threaded portion of the shaft, a driven crank wheel and a link and lever train between the crank wheel and the nut whereby the latter is reciprocated and the shaft of the article holder oscillated.

5. The combination stated in claim 1 having means for guiding the tangential movement in a manner conformable to the shape of the article.

6. In a machine for grinding and/or polishing articles the combination of a rapidlyrevolving wheel, a freely movable revolvable head, means for holding the said head with a yielding force toward the wheel, a plurality of article holders carried by the said head, means for revolving with a step by step motion the head to bring the articles in the holders successively into position to be acted on by the wheel, and means for giving to the holder whose article is being acted on by the Wheel'and while the head is at rest, tangential movements, rocking movements and tilting movements.

7. In a machine for grinding and/or polishing articles the combination, of a rapidly revolving wheel, a freely movable revolvable head, means for holding the said head with a yielding force toward the wheel, a plurality of article holders carried by the said head, means for revolving with a step by step motion the head to bring the articles in the holders successively into position to be acted on by the wheel, and means for giving to the holder whose article is being acted on by the wheel and while the head is at rest, tangential movements and rocking movements about the major axis of the article.

8. In a machine for grinding and/or polishing articles the combination of a rapidly revolving wheel, a freely movable revolvable head, means for holding the said head with a yielding force toward the wheel, a plurality of articleholders carried by the said head, means for revolving with a step by step motion the head to bring the articles in the holders successively into position to be acted on by the wheel, and means for giving to the holder whose article is being acted on by the wheel and while the head is at rest, tangential movements and tilting movements in the direction of the length of the article.

9. In a grinding or polishing machine, the combination of a rotating wheel, an intermittently driven head, a lever pivotally mounted on the head, an article holder supported by the said lever, a stationary, recessed rest cam past which the said lever is moved by the head operating when the lever comes to position opposite the recess to bring the article into working engagement with the rotating wheel and also into working engagement with means for moving the holder, and when the lever is moved opposite the non-recessed portions of the rest cam it is held out of working position, an eccentric drive arranged to impart rapidly repeated movements to the holder for moving the article upon the revolving wheel when the lever is opposite the recessed part of the rest, and other driving gearing also brought into operation at the same time for imparting to the holder other and different movements.

10. The combination stated in claim 9, including as a further and additional element, means for adjusting the extent of the movements imparted to the .article holder.

- 11. In a grindingi'nachine the combination with a revolving wheel, of an intermittently driven revolvable head rotatable stepwise, carrying the articles, holders for the individual articles operating against the revolving wheel, means for holding the said head with a yielding force towards the wheel, and means for imparting to the.holders while the head is at rest, tangential movements, rocking movements and tilting movements, and means for bringing the article into engagement with the rotating wheel for a predetermined length of time. 7

12-. In a grinding and polishing machine, the combination of a polishing wheel, a revolving head for the articles to be acted upon, holders carried by the head for the individual articles,

ARTURFRI'IZ KELM.

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