US2799974A

US2799974A - Polishing apparatus

Info

Publication number: US2799974A
Application number: US429942A
Authority: US
Inventors: Chester A Andrysick; Wilbur C Palmer
Original assignee: Corning Glass Works
Current assignee: Corning Glass Works
Priority date: 1954-05-14
Filing date: 1954-05-14
Publication date: 1957-07-23
Anticipated expiration: 1974-07-23

Description

C. A. ANDRYSICK ETAL July 23, 1957 POLISHING APPARATUS 2 Sheets-Sheet 1 Filed May 14', 1954 Q INVENTORS (2 5mm 4. 10mm? vs: c-Ic BY AND M4 BEA? CP/QLMEA M ,7. 041

July 23, 1957 c. A. ANDRYSICK ETAL 2,799,974

POLISHING APPARATUS Filed May 14, 1954 2 Sheets-Sheet 2 Y Y 75 82 Y Y I5 32 CYL- A. CYL. v

x INVENTORS 5'? E 73 85 Y (#5575? 14. film 019x51 CK 1' na MLBER C P/ILMER X may ATTOR Y.

United POLISI-HN'G APPARATUS Chester A. Andrysick and Wilbur C. Palmer, Corning, N. Y., assiguors to Corning Glass Works, Corning, N. Y., a corporation of New York Application May 14, 1954, Serial No. 429,942

7 Claims. (Cl. 5155) The present invention relates to an apparatus suitable for use in polishing the relatively large surfaces of tools or work-pieces employed in the formation of glass articles, such for example as those used in the pressing of the viewing screens of television picture tubes.

According to the invention facilities are provided for effecting back and forth movements between a work-piece and a rotating polishing head slidably engaged therewith to polish the work-piece surface between two oppositely disposed margins thereof. In the meantime similar transverse movements are effected back and forth between the polishing head and the work-piece to polish the workpiece surface between the remaining opposite margins thereof. Such latter movements are arranged to occur at a relatively slow rate of speed such that, for each first defined relative movement between the head and the work-piece, the distance of transverse movement amounts to less than the width of the polishing head. The arrangement thus is such that for each first defined pass or movement the head engages an area overlapping that engaged thereby during the preceding similar pass. As will be understood the respective back and forth movements are continued until the polishing head has imparted the desired surface quality to the work-piece.

In the accompanying drawings:

Fig. 1 is a top plan view of a preferred form of machine embodying the invention having arranged thereon a workpiece comprising a television viewing screen forming mold.

Fig. 1a is an enlarged view taken on line 1a-1a of Fig. 1.

Fig. 2 is a side elevation of the machine showing certain parts thereof and the work-piece thereon in section.

Fig. 3 is an enlarged view, partly in section, of the polishing head and a portion of the spindle assembly of the machine.

Fig. 4 is an enlarged plan view of a fragment of a frame of electrical insulating material, supported by the workpiece arranged on the machine, and carrying contacts co-operative with a contactor carried by the polishing head spindle and employed in controlling the back and forth movements between the polishing head and the workiece.

P Fig. 5 is an enlarged view taken on line 55 of Fig. 4; and also shows, in elevation, the polishing head and the lower portion of its supporting spindle assembly.

Fig. 6 is an enlarged view taken on line 6-6 of Fig.4.

Fig. 7 is a combined wiring and piping diagram of the machine, and includes a sectional view of one of the valves employed in effecting the back and forth movements hereinfor referred to.

Referring to the machine in detail, it embodies a frame 11 the top of which is employed as a track 12 for. a carriage 13 adapted to receive a work-piece such as mold 14. The carriage 13 is adapted to be reciprocated over track 12 by means of a fluid operated unit whose cylinder 15 is fixed to frame 11 and whose operating rod 16 is coupled to the carriage 13 through suitable cushioning springs 17.

The polishing head 21, shown in polishing engagement with the mold 14, is supported on a vertically disposed spindle assembly 22 mounted in a suitable bearing 20 carried on one end of a horizontal rod 23 running parallel to the track 12 and at its other end secured to a bracket 24. Bracket 24 is provided with a motor 25 by means of which the polishing head 21 is rotated through the medium of a belt 26. Bracket 24 is pivoted to a cap assembly 28 about a horizontal axis 27 extending normal to the rails of track 12. Assembly 28 in turn is pivotally supported about a vertical column 30. A horizontally disposed arm 31 is secured at one end to the side of assembly 28 (Fig. 1a) and at the other end is resiliently coupled through springs 17' (Fig. l) to the rod 32 of a fluid operated unit whose cylinder 33 is pivoted at 34 to the frame 11. As will be seen therefore, by means of the unit embodying cylinder 33 it is possible to oscillate the polishing head 21 between the lateral margins of the work-piece or mold 14. A weight 40, slidable along rod 23, permits the pressure applied by the polishing head 21 to the work-piece to be suitably regulated to obtain the polishing action desired.

The supplying of fluid to the respective fluid operated

unit cylinders

15 and 33 as required to reciprocate carriage 13 and to oscillate the head 21 is effected by means of conventional magnetically actuated four-way control valves 7 0 and 71 (Fig. 7) respectively, which are identical in all respects. Valves and 71 are in turn adapted to be controlled by a set of relays A to D whose respective operating circuits include a contactor 35, carried by the bearing 2%) of the spindle assembly 22, and in contact such as 1, 2, 3 or 4 carried by a frame 61 of electric insulating material arranged on the work-piece or mold 14. The lower side of frame 61 is provided with a number of blocks such as 51 (Fig. 5) adapted to register with suitable notches such as 51 in the work-piece and thus hold the frame fixed with respect thereto during a polishing operation. Arranged on two of the oppositely disposed upper surfaces of frame 61 are contacts 3 and 4 (Figs. 1, 4 and 7) which are fixed with respect to the frame. On each of the remaining two oppositely disposed upper surfaces of frame 61 are plates hereinafter referred to as contacts 1 and 2, that extend the width of the work-piece surface to be polished and are mounted for limited sliding movement under brackets such as 60 on the frame 61 in the directions of movement of carriage 13, but normally pulled toward one another by suitable springs such as 41. The contacts 1 and 2 have slotted ends such as 63, illustrated in Fig. 6, which straddle aligning pins such as 64 passing through the bracket 60 and frame 61. As will be more fully described hereinafter, contacts 1 and 2 are engaged by contactor 35 through the movement of carriage 13 and are included in the circuits of relays A and B, respectively, employed in the actuation of valve 70 to control the reciprocation of the carriage.

Contacts

3 and 4 on the other hand are engaged by contactor 35 through movement of head 21 and are included in the circuits of relays C and D, respectively, employed in the actuation of valve 71 to control the oscillation of the head 21. Relays A and B through the medium .of control valve 70 cause fluid to be supplied to cylinder 15 in the fashion necessary, as will become clear hereinafter, to effect the reciprocation of its rod 16. This results in the reciprocathe lateral margins of mold #14 with which

contacts

3 and 4 are associated. from a detailed description of the 'operations'oceurring under control of relays C andD the operations that occur under'control of relays-A and Bwill be;evident. 3 1

mold 14 as required to alter- -With relay C deenergized, as showiiit will be observed that a closed circuit exists through the magnet 86'pf valve -71 and that accordingly the spool of this valve has been moved to its leftward position. This circuit extends from aterminal X-of a; suitable current source, through the back contacts of relay C and the winding to a Y terminal of the same current source. V V

- Op'erating'fluidis supplied to cylinders'15 and 33 from a suit ableireservoir 69 by means ofa constant delivery pump 72 driven by' a'motor' 73. With the spool of valve -71 in the position shownjfluid from pump 72 passes through a check'valve 74, line 75, through valve 71, line 78, needle valve '79, and to the right end'of cylinder 33. At th'esame time a path for the return of fluid from the 'left'end of cylinder 33t0 the reservoir 69 extends via line 81, needle valve 82, the valve '71 and line 83. The rod 32 is at the present time accordingly moving in the direction indicated by the arrow. By reference to Fig. 1 it will be seen that with the rodi32 moving into cylinder 33, as indicated in Fig. 7, the polishing head 21 will be moving towardcontact 3. Therefore, ultimately, during one of the reciprocating movements of'carriage 13 the contactor 35 will engage such contact. When contact 3 is engaged by contactor 35 relay'C becomes energized over a circuit extending from the terminal X of a suitable current source, through the winding of relay C, contact 3, contactor 35 and a Y terminal of the same source. Relay C, upon becoming energized, at its innermost contacts 66, completes a locking circuit for itself including a conductor 67 and the break contacts 68 of'relay D, at its outer break contact 69, interrupts the circuit through magnet 86 and at its outer front contact 76 completes a circuit for magnet 87. As a result of the completion of thi latter circuit, thespool ofmagnet 71 is moved to the right, thereby reversing the fluid connections to cylinder 33 to efifect a reversal in direction of movement of rod 32 and a consequent reversal in direction of movement of the polishing head 21. As will be quite obvious, at such time that the contactor 35 engages contact 4 relay D will become energized and thus break the locking circuit of relay C so that it will restore and thus reestablish the set of conditions prevailing at the outset of the description. As will be understood the

needle valves

79 and 82, included in the fluid lines 78 and 81 between valve 71 and cylinder 33, are provided for the purpose of slowing up the transverse movement of head 21 to the extent required to assure that for each relative movement between the polishing head and those margins of the mold with which contacts 1 and 2 are associated, the distance of transverse movement of the polishing head will be less than the diameter of its polishing surface, so that overlapping of the preceding engaged surface will be assured.

, Itrwill be observed that with relay A deenergized the magnet winding 90 of valve 70 is' presently energized and that, accordingly, the spool of such valve is occupying its rightward position, as indicated. Therefore, at the present time fluid is beingsupplied to the left end of cylinder 15 through line 76 and, accordingly, rod 16 and the carriage 13 connected thereto are moving to the right.

4 der 15 following the engagement by contactor 35. V

In order to protect the operating mechanism should a reversal in direction of movement of either the head 21 or of the mold carriage 13 fail to occur when intended, the operating circuits of the

motors

25 and 73 are passed of one of such contacts through the break contacts of a relay E. Relay E in turn has alternate operating circuits closeable by contacts 88 adapted to be operated by rod 16 in either direction of its movement and similar operating circuits closeable by contacts 93 adapted to be operated by rod 32, should either of such rods fail to reverse its direction of movement substantially immediately after the contactor engages its controlling contact carried by frame 61.

Although the invention has been disclosed with the form of work-piece support carriage and contact carrying frame that are most suitable for the particular work-piece shown, it will be understood that the form of work-piece support and of the contact carrying frame are wholly determined by the shape of the particular work-piece to be polished. It will be obvious, therefore, that variations of the invention necessary for the polishing of work-pieces of other forms may be made within the scope and spirit of the appended claims.

What is claimed is:'

1. In a polishing machine, a length of track, a workpiece support carriage arranged on said track, a rotatable Contacts 1 and 2 are made slidable to permit a limited I polishing head arranged over said carriage and adapted to engage the surface of a work-piece thereon to be polished, means for moving said carriage back and forth along said track to progressively associate said head with different surface areas of the work-piece, means for mov-. 7

ing said polishing head back and forth transversely of the track to progressively associate said head withother surface areas of such work-piece, electric control circuits for both of said means, and a contactor common to said circuits for closing one of said circuits consequent to the arrival of, the work-piece at either of alternate predetermined positions along the track and upon the arrival of the head at either of alternate predetermined lateral positions with respect to the work-piece to reverse the direction of movement of the carriage or of the head as the case may be. p

2. A polishing machine such as defined by claim 1, wherein said electric circuits each include said contactor and a diflerent companion electric contact element arranged in the vicinity of each one of such predetermined positions.

3. A polishing machine such as defined by claim 2 wherein said contact elements are carried by a frame supported on the work-piece.

4. A polishing machine such as defined by claim 3 wherein a spring is arranged between said frame and at least one of said contact elements to impart a resilient yielding character thereto when engaged by said contactor. f

5. In a polishing machine a length of track, a work- .piece support carriage arranged on said track, a rotatable polishing head arranged over said carriageand adapted to engage the surface of a work-piece thereon to be polished, means for moving said carriage back and forth along said track to progressively associate said head with different surface areas of the work-piece, means for moving said polishing head back and forth transversely of the track to progressively associate said head with other surface areas of such work-piece, relays under whose control the respective back and forth movements are effected, a frame adapted to be carried by the work-piece having contacts bordering the boundary of the region of the work-piece to be polished included in the respective circuits of said relays, and a contact element carried'by the polishing head spindle included in the circuit of each 6. A machine such as defined by claim 1 wherein each of said control circuits includes a different relay.

7. A machine such as definrd by claim 6 wherein magnetic valves for effecting such reversals are under the selective control of said relays. 5

References Cited in the file of this patent UNITED STATES PATENTS 1,180,260 Grice Apr. 18, 1916 10 1,783,960 Fox Dec. 9, 1930 1,927,007 Whittles Sept. 12, 1933 6 Brown May 22, 1934 Shaw Feb. 8, 1938 Nenninger Mar. 15, 1938 Baldenhofer Apr. 5, 1938 Wortondyke Jan. 23, 1945 FOREIGN PATENTS Germany Feb. 18, 1904 Great Britain Dec. 3, 1929 Great Britain May 19, 1930