US2839876A - Burnishing machine - Google Patents

Description

June 24, 195% J. J. MURTAGH arm.

BURNISHING MACHINE 5 Sheets-Sheet 1 Filed Dec. 12, 1956 INVENTQR. James J. Murfa ATTOR NE VJ June 24, 1958 ,1. J. MURTAGH ETAL 2,839,876 BURNISHING MACHINE Filed Dec. 12, 1956 V 5 Sheets-Sheet 2 INVENTOR. dames d. Murfagh C/arencc (I. K/nker 'BY I 2 June 24, 1958 J, ,1, MURTAGH g-r 2,839,876

. BURNISHING MACHINE Filed Dec. 12, 1956 5 Sheets-Sheet 5 INVENTOR.

dame: d Murjagh C/arer/ce C. Inn/(er alum of metal, glass or plastic.

.Ufl States Patent 2,839,876 Patented June 24, 1958 fitice BURNISHING MACHINE James J. Murtagh, Toledo, Ohio, and Clarence C. Kinlrer,

Manitou Beach, Mich., assignors, by mesne assignments, to James J. Murtagh, Toledo, @hio ApplicationDecember 12, 1956, Serial No. 627,768

' 3 Claims. (Cl. 51,99)-

This invention relates to burnishing machines of the type employing rubber orthe like burnishing mats cooperating with an abrasive suspended in a liquid to produce a fine, smooth finish on articles of irregular contour Such machines havev been found. to have especial utility in the finishing of metal articles of irregular contour preparatory to plating, and to the finishing of more nearly planar glass articles such as the faces of television tubes.

The primary-object of the invention is to provide a machine in which the productive capacity of a worker can be increased by so arranging the machine that a single attendant may load-and unload a plurality of work bearing tables, while work continues on parts carried by another group of tables.

Known'machines of the general class operate in such a manner that it is not feasible to load parts of widely varying characteristics into the machine. An important object ofthe present invention is to provide amachine in; which several kinds of parts can be finished at the same time, thus making short productionruns economical.

Another object of the invention is to provide a machine in which the pressure exerted by a burnishing elementon the work can be readily variedor adjusted, and different pressures exerted on different groups of tables.

Another object of the invention is to provide amachine in which the accessibilityof the work table on which the parts to be finished are loaded and unloaded is improved over previous machines of this character.

Other objects and advantages of the invention will become apparent from the following description of a preferred: embodiment thereof, reference being had to the accompanying drawings, in which- Fig. l'is a central vertical sectional view of a machine embodying the present invention, the table drive mechanism having been omitted for the sake: of clarity;

Fig. 2 is a side elevational view of a machine embodying the present invention;

Fig. 3 is a fragmentary side elevational view showing the head in an operative position different than shown in Fig. 2;

I Fig. 4 is. a fragmentary sectional detail view of the trunnion mounting for one of the head operating hydraulic cylinders, taken on line 44 of Fig. 3;

Fig. 5 is a fragmentary sectional view showing the Qwork holding table and drive and mounting means:therefor;

Fig. 7 is a perspective view of one form of burnishing means usable in the machine of the present invention.

Fig. 6.is a side elevational .view, with parts in section, of the fluid cylinder and piston for moving the head,

showing theadjusting means therefor; andshown in Fig. l.

designated 50, 51', 52"and- 53 in the drawings. and 51 mountthe drum on the left side of Fig. 1 and 2 each other slightly as viewed from the end of ,the machine and are spaced apart in pairs as is shown in Fig. 1.

Each sump carries a work table 16. The mounting and driving mechanism for each work table is identical so that only one need be described. As shown in Fig. 5 the table 16 is bolted or otherwise fixed to a flange 18 at the end of a substantially vertically disposed drive shaft 20. Suitable spacer blocks 22 are interposed between the table and the flange 18 to change the elevation of the table relative to the bottom of the sump 14. The drive shaft 20 is made hollow and is carried down through a journal or hearing 24 which is fixed in the bottom of the sump 14 and sealed with respect thereto either by welding or by using an appropriate liquid tight seal so that the abrasive liquid carried in the sump cannot reach the bearing for the shaft 20.

If desired, the shaft may be made hollow and may be provided with an appropriate series of ports 26 which receive compressed air from a supply 28 and transmit it. to a radially directed passage 30 in the flange 18.

The drive shaft 20 is relieved as at 26 and registers with a series of ports 27 from which compressed air from a supply 28' may be passed to a vertical conduit 29 within the shaft 2% which, in turn, registers with a radial passage 30 in the flange 18. Air for the operation of suitable clamping fixtures on the surface of the table 16 may be obtained from the passage 30. Pneumatically operated clamps or fixtures are well known in the art and a detailed description thereof is unnecessary.

The'drive. shaft 20 is driven through any conventional gearing. disposed within a housing 32, the drive for which is taken from a speed reducer 34 and, as shown in Fig. 2, from a belt connected drive motor 36. It will thus be seen that'the drive motor causes the table to turn about the axis of its drive shaft 20.

The present invention is particularly concerned with the operation of the mounting and operating means for the rubbing or burnishingv element. As shown in the drawings the rubbing element may comprise a number of sets of elongated finger-like elements which are preferably madeof rubber. The elements are associated with each other and with a driving drum 40 and are themselves indicated by'the reference numeral 42 in Figs. 1 and 2. Hereinafter, the rubbing elements and their mounting means are sometimes referred to as burnishing heads or burnishing mats.

For some work it has been found that burnishing mats comprising radially extending rubber fingers or fiails are satisfactory, while for work'of a different character, for example, as smoothing 'a glass surface of slightly convex form, a burnishing mat comprising an inflated rubber cylinder will result in a better surface on the finishedwork. 'Fig. 7 shows a section of a suitable flailtype element comprising a base strip B for attachment to the drum, and radial fingers F from which a multiplicity of rubbing protuberances G extend. The protuberances extend from each side so that the element is reversible. Such a cylinderis indicated diagrammatically in Fig. 3, while flexible rubbing elements of the rubber-fingered flail type are shown in Figs. 1 and 2. These flail-like elements may be fixed to the central driving drum or cylinder 40 in any suitable manner as by clamping strips 44.

In the machine shown in the drawings there are two burnishing heads in longitudinally spaced relationship as Each of ,these rubbing elements, or burnishing heads, cooperates alternately with a front-andback spaced pair of work tables 16, and the axis of rotation of the rubbing elements is perpendicular to the axis of rotation of the Work-carrying tables 16.

E'achdrum 40ismountedin spaced bearings which are Bearings at the end of radius arms 52 and 53'. and 53' are journaled over a shaft 56'extending between uprights in the frame so that the arms are free to swing cylinders 70 and 71 for this purpose.

the bearings are carried at the end of radius arms 50, 51 extending upwardly from a lower bearing shaft 55 which is mounted between the sides of certain of the frame uprights. Similarly, thedrum 40 at the right hand side 'of Fig. l ismounted in bearings 52 and 53 carried The arms 52' about the shaft 56 as an axis.

The drums and thus the burnishing heads are driven from a common drive motor 57 through a sprocket 58 carried at the end of the motor shaft and meshing with a drive chain 59 which, in turn, turns a pinion 60 journaled on a reduced section of the drum mounting shaft 55. As indicated in Figs. 1 and 2 an integral step-up pinion 61 is associated with the pinion 60 and a driving chain 62 meshes therewith and with a final drive pinion 63 keyed or otherwise fixed to the drum mounting shaft which is designated 46 in Figs. 1 and 2. The shaft is thus rotated from the motor 57 at any desired speed, de-

ending on the ratio of the several sprockets and pulleys 53, 6t fill and 63. Since the axis of the driving sprocket 61 is the same asfthe axis of the shafts 55 and 56 on which the arms 50', 51", 52' and 53 are mounted, and the axis of the final drive sprocket 63 is on the same center line as the drum shaft the shaft can be driven from the motor 57 even though it swings from side' to side about the axis of the shaft 55 or 56 as indicated in Figs. 2 and 3.

Any suitable means may be provided for moving the radius arms 51' and 52' to bring the rubbing elements first over one table and then over its spaced companion table. The present invention, however, preferably includes opposed hydraulic operators including opposed Each cylinder is backed at its outer end against a trunnion or frame member while the inner end of its piston rod is fixed to a shaft 73 which extends between the radius arms 51 and 52. Hydraulic pressure applied to one of the cylinders will cause its piston to move outwardly and thus move the arms 51 and 52 about the center of the mounting shaft 55, 56. This motion will continue until it is stopped by the opposition of the piston in the opposing cylinder it? or 71. Since it is desirable that the stroke of the machine be adjustable the present invention includes means to predetermine the extent to which the piston can travel inwardly in its hydraulic cylinder and this means is shown in Fig. 6.

As shown in Fig. 6 the cylinder 79 is fixed at its lowerat 78 in Fig. 6 and extends outwardly to connect to the shaft 73 which, as above stated, extends between the pivoted arms 51' and 52 to move the latter during operation of the machine. in Fig. 6 the piston is shown appreaching its innermost position with respect to the cylinder '70. Oil enters the cylinder from a pipe or passage 2% and passes a check valve 81 to enter the space beneath the piston. As the piston is forced outwardly of the cylinder by the oil pressure it moves the shaft 73 and the burnishing heads from one side of the machine to the other. The pipe or passage 80 serves both as a supply and discharge passage and is controlled by a suitable three-way valve diagrammatically indicated at 82 which is connected to a source of fluid pressure 83 and to a drain 84. Thus, depending on the position of valve 81 which may be determined by automatic means, oil will be supplied to or drained from the associated power cylinder.

in opposing the motion of the heads as above described by an active piston, the piston 78 can also, as it moves into the cylinder, limit the extent to which the heads will be moved. It will be seen that the piston 78, as it enters .the lower end of its associated cylinder comes into a frame of the machine.

86 extend. A final lower restricting passage 87 extends from the bottom of the dashpot 84. Thus oil trapped in the dashpot by the advancing piston canfiow out to the drain only through the restricted passages 86 and 87 which are progressively covered by the piston so that its movement is progressively slowed until finally it comes to rest against the bottom of the dashpot 85, but without any perceptible bumping.

The position of the bottom of the dashpot can be varied so that the extent of the outward movement of the piston can be changed at will. For this purpose the dashpot is constructed as a separate element fitting closely in its associated cylinder. A keyway 88 is cut in one side of the dashpot and cooperates with a key 89 extending radiallyinward from a side wall of the cylinders. The keyway serves also as a drain passage for the dashpot restricting outlet passages 86. The body of the dashpot 85 is threaded to cooperate with an adjusting screw 90 formed on the inner end ofadjusting shaft 76. Thus as the adjusting shaft 76 is turned manually by the operator, as by turning a handle 91 the screw 90 will feed the dashpot in or out of the cylinder to change the position at which the piston will be stopped in its movement into the cylinder. As will become apparent hereinafter this change in piston movement is used to adjust the pressure of a burnishing means on the work and to adjust the machine for diiferent types and sizes of workpieces. 7 f

Each of the burnishing heads is surrounded by a casing 95 which is open at its bottom but closed on the The casing isfixed in appropriate side members associated with the journals 50, 51 and 52 and 53. The motion of the heads and casing is guided 'not'only by the radius arms 50', 51 and 52', 53 but also by end links 96 which are pivoted at one end to the casing and at the opposite end to a pin 97 fixed to the The link 96 thus forms with the adjacent arm 50' or 53 a parallel guide for the casing so that the latter is brought always to a position in. which the underlying sump is covered, and liquid thrown by the burnishing means cannot escape. A small sectionof the lowermost part of the front and back of the cover can, if desired, be made of a flexible material such as rubber or heavy canvas so that it can come up closely against the interior of the sump without bumping and cangstill produce a joint that is not subject 'to undue leakage.

Liquid burnishing material can be supplied to the space between the burnishiug'mat and articles held on the rotating tables 16 in any suitable manner. In some instances it may be desirable to feed the abrasive carrying liquid through the center of the drums 40.and to spray it out radially between the circumferentially spaced In other instances it has been found best to flood the work with the abrasive-carrying liquid by spraying relatively large quantities thereof onto the work when it is exposed from under the burnishingmat. To this end, each of the casings around the respective burnishing mats is provided with front and rear supply tubes 100 which are preferably on the exterior of the casing and extend longitudinallythereof for the full length of whatever rubbing elements arecarried by the drums 40. Nipples 102 extend through the casing from the supply tubes 100 and are directed downwardly towards the table. The bore and spacing of the nipples may be readily changed to increase or decrease the flow of abrasive liquidto the work surface. The liquid is supplied from a suitable tank (not shown) by any. conventional pump diagrammatically indicated at 104 in Fig. 2. After flowing over the work the liquid collects on the bottom of the sumps 14, each of which is provided with a suitable drain 106 by which liquid is returned to the supply tank. The drain'size is such that the liquid level never rises above the top of the bearing 24 through which. it

might run onto the drive shaft 20 for the table. In this Way the shaft is amply protected against the action of the abrasive.

In operation, the tables 16 on one side of the machine are loaded with parts to be finished and the tables set into operation, being turned by motors 36. The liquid pump is started, and the drive motor 57 for the burnishing heads is likewise put into operation. Automatic sequence controls may be provided which determine the interval that the burnishing heads are disposed over either pair of work tables. For example the cycle may be so arranged that the heads dwell for twenty seconds over the front pair of tables 16, then swing to the rear set of tables and dwell-thereover for thirty seconds before returning to the front pair. Thus difierent kinds of work can be done in the front and rear pairs of tables. The cycle is, of course, determined by the admission of pressure fluid into cylinders 70 and 71 which cause the burnishing heads to swing back and forth from working positions over the front and rear pairs of tables. The drive motor for the burnishing heads runs continually, as do the tables and burnishing fluid supply motors. If desired, the burnishing heads may differ from one another, that is the machine may carry a flail-type head and an inflated cylinder head side by side. Since work progresses on one group of tables while the other group is being loaded and unloaded, operation is very efiicient. Preferably the cycle is arranged so that the table drive motors stop as soon as the burnishing heads leave for a traverse to the opposite group, and start automatically prior to the arrival of the heads.

As heretofore described, the spacing between the active part of the burnishing heads and the tables can be changed by the operator by simply turning the handles 91 to adjust the inward position of the bottom of the dashpots 85 against which the pistons 78 come to rest at each stroke. It is thus feasible to exert different pressures on the work on the front and back groups of tables.

The burnishing mats, having a motion that is rectilinear and across the diameter of the work tables, are capable of imparting a very fine finish to parts having longitudinal ridges and grooves. It is only necessary that the axis of the groove or ridge coincide temporarily with the line of motion of the flail or finger of the mat. If the work is of a smooth, nearly planar character, a soft inflated rubber cylinder may advantageously be used as a burnishing or rubbing element. Such a mat shows less tendency to leave minute depressions in the work surface that give an orange peel appearance when the work is ultimately plated. Such mats are also advantageous for finishing glass surfaces such as the faces of television tubes.

It has been found that one operator can easily load and unload two or more work tables while the machine runs continuously. Thus with one man on each side of the machine, very rapid finishing of a large number of similar parts is easily accomplished.

While the invention has been described in conjunction with a specific form and disposition of the parts, it should be expressly understood that numerous modifications and changes may be made therein without departing from the scope of the appended claims.

What we claim is:

1. In a machine for finishing articles by the coaction of a rotatable flexible rubbing element and an abrasivecarrying liquid, the improvement comprising a plurality of spaced rotatable work-carrying tables, swinging arm means to mount said rubbing element for movements to cooperate with said work tables successively, means to introduce abrasive-carrying liquid between said rubbing element and articles carried by said work tables, and means to adjust the extent of swinging movement and thus the operative position of said rubbing element over each of said work tables.

2. A machine in accordance with claim 1 in which said mounting means includes a hydraulic cylinder and piston and said adjusting means comprises a device to limit the movement of said piston.

3. In a burnishing machine, the combination of a plurality of longitudinally spaced work tables comprising a first group, a second group of longitudinally spaced work tables, means to rotate all of said work tables about generally upright axes, a plurality of burnishing heads corresponding in number to the number of tables in a group, means to mount said burnishing heads for swinging movements from a position over one group of tables to a position over the other group of tables, means to rotate said burnishing heads about a generally horizontal axis, said mounting means including hydraulically operated pistons connected between the axis of rotation of said burnishing heads and a stationary part, adjustable means to limit the movement of said pistons and thereby the relative spacing of said burnishing heads and said tables, and means to supply an abrasive-carrying liquid between said burnishing heads and work carried by said tables.

Law Sept. 12, 1933 Kinker Mar. 26, 1957

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