US2070944A

US2070944A - Method and apparatus for finishing surfaces

Info

Publication number: US2070944A
Application number: US684358A
Authority: US
Inventors: Foster F Hillix
Original assignee: American Steel and Wire Company of New Jersey
Current assignee: American Steel and Wire Company of New Jersey
Priority date: 1933-08-09
Filing date: 1933-08-09
Publication date: 1937-02-16
Anticipated expiration: 1954-02-16

Description

Feb. 16, 1937. F. F. HILLl-X METHOD AND APPARATUS FOR FINISHING SURFACES 5 Sheets-Sheet 1 Filed Aug. 9, 1933 Feb. 1 6, 1937.

F. F. HlLLIX METHOD AND APFARATUS FOR FINISHING SURFACES Filed Aug. 9. 1933 5 Sheets-Sheet 2 Feb. 16, 1937. F. F. HILLlX METHOD AND APPARATUS FOR FINISHING SURFACES Filed Aug. 9,- 1933 5 Sheets-Sheet 3 //vvE/vra.e.

Fosnse A 1 /14:. /x 7 fla 7M Arron/vars Feb. 16, 1937.

F. F. HlLLlX METHOD AND APPARATUS FOR FINISHING SURFACES Filed Aug. 9, 1933 5 Sheets-Sheet 4 w eu Y i M WM n w .Feb. 16, 1937. F. F. HlLLlX 7 METHOD AND APPARATUS FOR FINISHING SURFACES Fileci Aug. 9. 1933 5 Sheets- Sheet; s

' Arne/vs Y's Patented Feb. 16, 1937 UNITED STATES PATENT OFFICE METHOD AND APPARATUS FOR FINISHING SURFACES tion of New Jersey Application August 9, 1933, Serial No. 684,358

$ 3 Claims.

The present invention relates to the production of accurate, smooth surfaces of high finish, and more particularly to a method of and machine for honing, lapping, grinding, bufiing, and/or polishing surfaces either plane or curved.

In the prior art, it has been common practice in the production of smooth surfaces to reduce the same by cutting or lapping operations employing wheels, such as abrasive wheels, and laping heads, wherein the surface is cut by a multiplicity of cutting points of irregular shape. The surfaces thus produced are characterized by having an unevenness identified by various terms, such as grain marks, orange peel, etc., which unevenness depends, among other things, upon the fineness or coarseness of the wheel and/or abrasive employed. Coarse wheels and/or abrasives are usually employed at first because they remove the stock rapidly and finer wheels and/or abrasive substituted therefor until he desired finish is produced.

Before the present invention, it has always been considered essential to eliminate all vibration from both the tool or wheel and the work, to which end the machines of the prior art have been built very heavy and rigid. But it has been found that controlled vibration of relatively high frequency, preferably in the nature of from 3,000 to 40,000 vibrations per minute, may be imparted to either the tool or the work, or both, with surprising results not only in the increased smoothness of the surface produced and its freedom from scratches, but in the increased rate of production.

An object of the present invention is the provision of a novel method of finishing and/or working surfaces, such as glass or metal, etc., wherein vibrations of relatively high frequency are imparted to either the tool or work, or both.

Another object of the present invention is the provision of a novel method of honing, lapping, grinding, buffing, and/or finishing surfaces wherein vibrations of relatively high frequency are produced in either the tool or the work, or both.

Another object of the present invention is the provision of a novel machine for finishing and/or working surfaces, such as metal surfaces, wherein controlled vibrations of relatively high frequency are imparted to either the tool or work, or both.

Another object of the present invention is the provision of a novel machine for honing, lapping, grinding, bufling, and/or finishing metal surfaces wherein controlled vibrations of relatively high frequency are produced in either or both the tool or wheel and work.

Further objects and advantages of the invention will be apparent to those skilled in the art from the following description of the preferred embodiment or embodiments thereof, described with reference to the accompanying drawings, in which:

Fig. 1 is a perspective view of a machine embodying the present invention I Fig. 2 is a rear view of the machine shown in Fig. 1;

Fig. 3 is an enlarged view of the flywheel shown in Fig. 1;

Fig. 4 is a perspective view of a modified construction of the machine shown in Fig. 1;

Fig. 5 is a sectional view of the machine shown in Fig. 4, taken immediately below the tool;

Fig. 6 is a sectional view taken on the line 66 of Fig, 5;

Fig. 7 is a perspective view of a machine embodying the present invention particularly adapted for polishing strips;

Fig. 8 is a perspective view of a machine embodying the present invention particularly adapted for honing or polishing cylindrical work;

Fig. 9 is a perspective view of a portable machine embodying the present invention;

Fig. 10 is a perspective view of a further modification of the present invention;

Figs. 11 and 12 are views of still further modifications of the present invention;

Fig. 13 is a perspective view of a lens grinding machine embodying the present invention, and

Fig. 14 is a perspective view of a further modification of the present invention.

Similar reference characters designate corresponding parts throughout the several views of the drawings.

Referring to the drawings, Figs. 1 and 2 illus-' trate a lapping or polishing machine suitable for lapping and/or polishing plane surfaces of material such as sheet metal, glass, etc. The work, designated by the reference character W, is sup ported on the top of a table 9, and, if desired. fixed thereto in any suitable manner. The table 9 is slidably supported on ways l0 formed on top of a bed I l and reciprocated thereon in any suitable manner well known in the art, preferably by means of fluid pressure operated mechanism. The mechanism for reciprocating the table 9 is not illustrated herein as it does not, per se, form a part of the present invention and is well known in the art, wherein it may be found embodied in a plurality of structures, but, sufiice it to say that the reciprocation is automatic and may be stopped and started at will by means of a push button switch i2.

In the machine illustrated, the operation being performed is that of lapping; and a plurality of lapping heads iii are shown in engagement with the upper surfage of the work W. The lapping heads i5 arer'otatably attached to the lower end of vertical shafts or rods I6, connected preferably by means of flexible couplings It to fluid pressure operated motors F. The motors F not only raise and lower the lapping units but aflord a very desirable means of applying the laps to the work with any desired pressure. The motors F, as fllustrated, are double action fluid pressure operated motors of the reciprocating type comprising cylinder rigidly secured to a frame, structure 2| formed integral with or attached to the bed It. The flow of fluid to the motors F is controlled by three-way valves 22 secured to the frame structure 2|. Gauges 25 indicate the pressure of the fluid applied to the motors and, in turn, the force with which the laps or tools are applied to the work.

It has been found that relative vibrations of small amplitude and high frequency between the tool and the work, in the plane of the surface being finished, produce a much superior surface or finish, and that the vibrations need only be in the nature of a few thousandths of an inch in amplitude and of a frequency from 1,500 to 20,000 cycles or 3,000 to 40,000 vibrations per minute to produce the desired result. It will be understood by those skilled in the art, from the foregoing description of the invention, that these vibrations may be produced bya plurality of diflerent means and that they may be imparted to either the tool or the work, or both.

In the embodiment of the invention illustrated, high frequency vibrations of low amplitude are imparted to the laps by rotating at high speeds unbalanced flywheels 25 rotatably supported on the shafts or rods it. The unbalanced condition of the flywheels is produced by havjng a hole 26 formed therein near the periphery. As illustrated,

the hole 26 is eccentrically located in a member 21 rotatably supported in an aperture in the flywheel and adjustable therein in such a manner that the hole may be positioned radially of the flywheel to change the unbalanced condition thereof, thus increasing or decreasing the power of the vibrations. The flywheels 25 are driven by means of belts 28 and a vertical shaft 29 from a motor 30 supported on the top of the frame structure The lapping heads l5 are preferably rotated at a slow speed from the shaft 29 through the medium of a worm gear reduction 6, see Fig. 2, and belts 3|, to equalize the wear on the lapping heads and distribute the abrasive which is preferably sprayed on the work in the form of a suitable liquid. Because of the small amplitude of the vibration imparted to the lapping heads l5, the flexible couplings l3 may be omitted but are preferably employed as they localize the strain. As illustrated, the flexible couplings i8 comprise two flanges bolted together with a piece of flexible material 32, such as rubber, between the adjacent surfaces thereof, but flexible couplings of other constructions may be .employed with equal facility.

As previously stated, the relative oscillation or vibration between the work and the tool may be produced by vibrating either the tool or the work, or both. In the embodiment of the invention just described, the vibrations are imparted to the tool,

and Figs. 4 to 6 inclusive illustrate a modified construction of the invention wherein the vibrations are imparted to the work. This latter conthat'the table 36 is provided with a movable or floating table top 65. The table top 3515 supported on ledges 36 at either end of the table 30 by rollers 31 attached to the under side of the table top. This construction permits free movement of the table top 35 transversely of the longitudinal axis of the table. Rollers 38, attached to the under side of the table top 35, engage the ends of the table 30 and prevent longitudinal movement of the table top 35 without interfering with the transverse movement thereof. Vibrations of relatively low amplitude and hig frequency are imparted to the table top 26 by unbalanced flywheels 39 similar in construction to the flywheels 25 already described. The flywheels 30 arerotatably supported on brackets fixed to the under side of the table top 35 and are driven, through the medium of belts 52, by a motor supported on a bracket 0| fixed to the table M. A drum type tool .65, rotatably supported above the table top 35 by a frame structure :15 somewhat similar to the frame structure, 2!, is driven at any desired speed by a variable speed motor 66 supported on the top of the frame structure 65. The motor is controlled by a push button switch 61. In order to accommodate work of variable thickness, etc., the tool M is supported in brackets 59 adjustable vertically along the front face of the frame structure 65 by a hand wheel 50, through the medium of lead screws, in a manner well known in the art.

Fig. 7 illustrates a construction of machine articularly adapted for polishing work W, in

the form of astrip, between a pair of rollers 56 and 56. The machine frame structure for supporting and the means for rotating the rollers are not shown as they are well known in the art and'may be found embodied in a plurality of different structures and means. A bracket 51 supported by a shaft 56 extends on either side of the strip W and is provided with an adjustable block 59 to accommodate diiferent sizes, of work. The shaft 58 is reciprocably supported in a hearing member 60 attached to abracket 5| bolted or otherwise secured to the machine frame 62. Vibrations of relatively high frequency and low amplitude are imparted to the shaft 58 and, in turn, to the work W as it is fed to the rollers and 56 by an unbalanced flywheel 65 rotatably supported by a bracket 66 fixed to the rear end of the shaft 58. The flywheel is similar in construction to the flywheels 25 and 39 previously referred to and is driven by means of a belt or in any manner well known in the art. A similar arrangement may be employed on the other side of the rollers 55 and 56, if desired.

Fig. 8 illustrates a modified construction of machine embodying the present invention and particularly adapted for lapping or honing cylindrical work. The work W is rotatably supported sired speed by a belt 93.

and driven at a desired speed in any manner well known in the art. A lap or hone 68 is fixed to one end of a shaft 69 connected to a shaft 10 by a flexible coupling 1I similar to the coupling I8 previously described. The shaft 10 is reciprocably supported in any desired manner by the machine frame. The mechanism for supporting androtating the work and for supporting the shaft 10, etc., is not illustrated as it does not, per se, form a part of the present invention and may be found embodied in a plurality of structures well known in the art.

High frequency vibrations of relatively low amplitude are imparted to the lap or hone by means of an unbalanced flywheel 15 rotatably supported on the shaft 10. The flywheel 15 is similar in constructionto the flywheels 25 and 39 and is driven at any desirable speed by a belt 16. Vibrations in the neighborhood of 15,000 per minute overcome any tendency of the lap or tool to ring the work, and produce a. very much finer surface than one would expect from the grain size of the tool. It is also possible by this method to use loose grain suspended in a proper medium and obtain a surface free from scratches.

While an unbalanced flywheel, directly connected to either the tool or the work support, has been employed to produce the vibrations referred to in all the machines thus far described and illustrated. it is to be understood, as stated above, that other means may be employed within the scope of this invention. For example, referring to Fig. 8, it will be understood that relative vibration may be produced between the work W and the lap or hone 68 by merely moving the lap or hone longitudinally of the work axis by means of a fluid operated piston working against a back pressure, and producing rapid impulses in the pressure of either the operating or back pressure fluid.

Fig. 9 illustrates a portable lapping machine capable of carrying out the improved method and embodying the present invention. The lap 80 is adapted to be clamped about the work W which is rotatably supported in any convenient manner. The work W is rotated at a desired speed by mechanism not shown, and the lap is manually moved longitudinally thereof. A handle 82 is provided for this purpose. The high frequency vibrations of low amplitude are imparted to the lap by means of an unbalanced flywheel (not shown), located within the housing 83 supported on a stub shaft 84 attached to the lap 80, and driven by a flexible shaft 85 in a manner well known in the art.

Fig. 10 illustrates the application of the present invention to a small grinding machine for finishing the surface of holes especially when there are no bottoms or shoulders. As illustrated, a tool 90 is supported by a chuck 9| fixed on a spindle 92 rotatably supported by the machine frame (not shown) and driven at any de- The spindle 92 is vibrated longitudinally of its axis by an unbalanced flywheel 94, similar in construction to the flywheel 25, rotatably supported in a member 95 pivotally connected to a member 96. The member 96 is rotatably supported on the rear end of the spindle 92, and rotation of the member 96 with the spindle 92 is prevented by the engagement of a lever 91 formed integral therewith in a slot 98 in a bracket 99 attached to the machine frame. The flywheel 94 is driven by a belt I00 or in any convenient manner. The small amount of movement of the wheel has no detrimental effect on the belt drive or the motor. The work is indicated at W.

In the case of large grinders, it is more practical to use fluid pressure to transmit the vibrations to the tool or work, and mechanism for transmitting longitudinal vibrations to a grinder spindle employing fluid pressure means is shown in Figs. 11 and 12. Referring to Fig. 11, the reference character IOI designates a grinder spindle of which only the ends are shown. The spindle IN is rotatably supported by the machine frame I02 and carries a suitable tool (not shown) intermediate the. ends thereof. The spindle IOI is continuously urged towards the left, as viewed in Fig. 10, by a compression spring I03. A thrust bearing I04 is interposed between the spindle IN and the spring I03. J

The spindle IN is vibrated longitudinally of its axis by a vibrating unit comprising an unbalanced flywheel I05 similar in construction to theflywheel 25. The flywheel I05 is rotatably supported on a bracket I06 and driven at any desired speed by a belt I01. The bracket I06 projects through an opening in a member I08 and is provided with an enlarged head which rests upon or is supported by a flexible diaphragm I09 to which it is attached by a bolt H0. The diaphragm I09 forms a cover for a fluid chamber III in the member I08, which chamber is a part of a closed fluid pressure system for transmitting vibrations produced by the rotation of the flywheel I05, from the diaphragm I09 to a similar flexible diaphragm II2 forming one side of a fluid chamber H4 in the machine frame I022.

The fluid chambers -III and H4 are connected by a pipe I I 5, and a pipe I I6 leads to an accumulator which maintains the system full of fluid. Vibrations imparted to the diaphragm II2 are transmitted through the medium of a thrust bearing II8 to the spindle ml by a member II1 bolted thereto. It will be apparent that a fluid pressure means similar to that applied to the left hand end of the spindle IOI may be substituted for the spring I03 for moving the spindle towards the left, as viewed in the figure.

Fig. 12 shows a modified construction of the arrangement shown in Fig. 11 adapted to be applied to or used in machines where the wheel or tool overhangs the spindle. The vibrating unit is similar to that shown in Fig. 11, except that there are two fluid chambers I23 and I24 formed in a member I25 operatively connected to two fluid chambers I26 and I21, formed in the machine frame I28, by pipes I29 and I30, respectively. The chambers I23 and I24 are closed by flexible diaphragms I3I and I32, respectively, connected to a bracket I33 by bolts I34 and I35. The bracket I 33 is rockably supported by the diaphragms I3I and I32 and held in position by a pin I31 which extends through an elongated slot I38 formed in the bracket. An unbalanced flywheel I 40, similar in construction to the flywheel 25, is rotatably supported at the upper ends of the bracket I33 and driven at any desired speed by a belt I.

Flexible diaphragms I44 and I45 which form covers for the fluid chambers I26 and I 21 are operatively connected to a bracket I 41 pivotally supported by the machine frame. The upper end of the bracket I41 surrounds the tool or wheel spindle I48 and is held between thrust bearings I50 and I5I positioned therebetween and collars I52 and I53 fixed to the spindle I48, From the foregoing description it will be apparent that vibrations set up in the bracket I 33 4 by the flywheel I40 will be transmitted to the spindle I48 through the medium of the fluid in the closed fluid system, and the bracket I41, etc.

The pipes I55 lead to an accumulator which maintains the pressure in the system.

Fig. 13 illustrates an application of the present invention to a. lens grinding machine. A rotatable work support, indicated at I60, is'adapted to support a plurality of lenses I6I. The tool or grinding head I62 is rotatably connected to a short shaft I63 supported adjacent the work support by a bracket I 64. Vibrations of the desired frequency and amplitude are imparted to the tool or grinding head I62 by an unbalanced flywheel (not shown), similar in construction to the flywheel 25, enclosed within the housing I65. The flywheel is driven by a flexible shaft I66 and the tool or grinding head is slowly rotated by the friction between the same and the work.

Fig. 14 illustrates a modified construction of the portable lapping machine shown in Fig. 9. In the embodiment of the invention illustrated in this figure vibrations of high frequency and low amplitude are produced in the tool by electrically operated mechanism. The lap I10, pro- ,vided with a handle I, is adapted to be clamped about the work W and moved thereby by manual or mechanical means. The work is rotatably supported and driven at any desired speed by mechanism not shown. An armature I12 secured to the lap I10, opposite the handle I, projects between the poles of an electric magnet I13 and is vibrated thereby. The electric magnet I13 is secured to a housing I14 by bolts I15 and has an electric coil I16 wound about the center thereof. The coil I16 is adapted to be connected to any suitable source of electric current by leads enclosed in the conductor I11. A rubber bushing I18 positioned between the armature I12 and the housing I" at the point where the armature extends through the housing, keeps the armature centered between the poles of the magnet. The frequency of the vibration can be changed and/or controlled by changing and/or controlling the frequency of the current supplied to the electric coil.

It will be understood that while an unbalanced flywheel has been shown in Figs. 1 to 13 inclusive for producing the vibration, electrical means similar to that employed in the device illustrated in Fig. 14, or any other means may be employed with equal facility.

From the foregoing description of the preferred embodiments of the invention, it will be apparent that the objects of the invention have been attained and that a novel method of and novel machines for finishing smooth surfaces of material, such as metal or glass, have been provided. The invention has been described with reference to the preferred embodiments thereof, but it is to be understood-that the invention may be embodied in other structures, such as breaching, planing or milling machines, etc.,

with equal facility, and I do not wish to be limited to the particular constructions illustrated and described, and particularly point out and claim as my invention the following:

I claim: 1. In a machine of the character described the combination of a base, a table slidably sup ported by said base, means for reciprocating said table, a frame fixed to said base and comprising a fluid pressure operated reciprocating motor comprising a piston rod, a shaft adapted to support a tool, a flexible connection for operatively connecting said shaft to said piston rod, an unbalanced flywheel rotatably supported by said shaft, and means for rotating said flywheel.

2. The method of working surfaces which comprises producing relative movement between a tool and a work-piece and superimposing vibrations of a frequency of more than three thousand per minute and of an amplitude of the order of a few thousandths of an inch upon said relative movement in the plane of the surface of the work-piece.

3. The method of working surfaces which comprises producing relative movement between a tool and a work-piece, and simultaneously vibrating the tool in the plane of the surface of the work-piece, said vibrations being of a frequency of more than three thousand per minute and of an amplitude of the order of a few thousandths of an inch.

FOSTER F. HILLIX.