US2709875A - Apparatus for grinding or polishing flat glass - Google Patents

Description

June 7, 1955 Filed Jan. 25

R. TOUVAY APPARATUS FOR GRINDING OR POLISHING FLAT GLASS 1951 3 Sheets-Sheet 1 Inventor June 7, 1955 TQUVAY 2,709,875

APPARATUS FOR GRINDING OR POLISHING FLAT GLASS Filed Jan. 25, 1951 3 Sheets-Sheet 2 WM Inventor way/(4 By June 7, 1955 R. TOUVAY 2,709,875

APPARATUS FOR GRINDING OR POLISHING FLAT GLASS Filed Jan. 25, 1951 s Shets-Shee't s w m 29 REVERSE FORWARD 58% m 59% m /8 REVERSE 35% L is 57 FORWARD a REVERSE FORWARD REVERSE FORWARD 43% 57 /0" T .:T" 58 Inventor By W WAflor-neys United States Patent APPARATUS FOR GRINDING OR POLISHING FLAT GLASS Robert Touvay, Paris, France, assignor to Pilkington Brothers Limited, Liverpool, England, a British com- P y Application January 25, 1951, Serial No. 207,701

4 Claims. (Cl. 51-112) This invention relates to apparatus for grinding, lapping or polishing the surface of flat glass, and which acts simultaneously in continuous progression on the two faces of a continuous ribbon of glass, in accordance with the method known generally as the continuous grind ing-polishing of two faces.

Patented J une 7, 1955 parallel with the plane of the work, and means to move the tools transversely across the path of the work in planes parallel with the plane of the work to a position at the side of the work at which position servicing or replacement of the tools may be effected, characterised in that the upper and lower tools of a pair are'mounted for In United States patent specification No. 2,508,863

there is described for grinding or polishing simultaneously the two faces of a continuous ribbon of moving glass an apparatus comprising pairs of upper and lower grinding or polishing tools, means for rotating the tools of each pair in planes parallel with the plane of the so that the positions of the upper and lower tools of a pair relative one to the otherremain unchanged and to this end the upper and lower tools of a pair are mounted in a single C-shaped support arranged for movement transversely of the direction of movement of the work in order to bring the tools to the side of the work for the purpose mentioned above.

The construction according to the prior proposal has W:

in practice been found satisfactory when the work is of relatively narrow width but for use in machines adapted for grinding or polishing work pieces of greater width the apparatus is less advantageous owing to the necessarily increased length of the arms of the C-shaped support and the fact that the tools are carried adjacent the free ends of the arms. Accordingly for workpieces of greater width, to ensure the C-shaped support having adequate strength and rigidity it must be given considerable proportions and weight. Further with this prior construction the upper and lower tools of a pair are always moved simultaneously to the servicing position, and if only the lower tool is to be serviced or replaced it is first necessary to dismantle the upper tool.

It is a main object of the present invention to pro- 9 vide an apparatus for grinding or polishing simultaneously the two faces of a continuous ribbon of moving glass in which the tools of a pair are movable independently one of the other to the servicing position beside the work without stopping the operation of the entire maf? chine.

A further object of the present invention is to permit the lower tool of a pair to be moved to servicing position independently of the upper tool so that it can be serviced or replaced without the necessity of first dismantling the upper tool.

According to the present invention there is provided for grinding or polishing simultaneously the two faces of a continuous ribbon of moving glass, an apparatus comprising pairs of upper and lower grinding or polishing tools, means to rotate the tools of each pair in planes rotation in independent supports each having traversing means associated therewith to effect movement of the tool transversely across the path of the work to said servicing position whereby the tools of a pair may be I separately moved to said position.

It will be readily understood that with apparatus according to the present invention the upper tool of a pair may be moved to servicing position whilst the lower tool remains in position beneath the work to provide a support for the work, this being an important feature when the work consists of a thin glass ribbon.

A further main object of the present invention is to provide an apparatus for grinding or polishing simultaneously the two sides of a continuous ribbon of moving glass in which the rubbing action of the tools results from the rotary movement thereof and an oscilla tory movement transverse to the direction of movement of the work which results in the crossing, on the work, of the trajectories of each grain of abrasive material thus resulting in a substantially even grinding or polishing and reducing or eliminating the condition known in the art as directional polish.

Accordingly the traversing means in apparatus according to the present invention may be operable to oscillate the supports in working position along said transverse paths whereby the grinding or polishing action of the tools results from the rotary and oscillatory movements thereof.

In apparatus according to the present invention the transverse movements of the supports may be'synchronized so that the axes of rotation of the'tools of a pair are maintained in alignment.

In order that the invention may be clearly understood one embodiment thereof will now be described, by way of example, with reference to the accompanying diagrammatic drawings which show the invention applied to a grinding unit and in which:

Fig. l is a view partly in section on line A--A, Fig. 2,

Fig. 2 is a plan of a part of a glass grinding machine having aratus according to the invention, the plan being partly in section on line B-B, Fig. l, and

Fig.3 is a section on line C-C, Fig. 2, and shows two consecutive bays of the machine.

Fig. 4 is a circuit diagram illustrating one mode of effecting operation of electric motors employed in the apparatus.

Referring to the drawings, the grinding tools of a pair comprise a lower tool 1 and an upper tool 2, the tools being illustrated in their working positions with respect F to the two sides of a glass ribbon whose median plane is represented by the lines X-Y, Fig. l, and ZZ, Fig. 3. The glass ribbon is moved along the machine by rollers 3, 31, Fig. 3, the rollers, as is usual, exerting a certain pressure on the glass ribbon.

The tool 1 is mounted for rotation in a support 4 and the tool 2 is similarly mounted in a support 5, the axes of rotation of the tools 1, 2 being substantially in alignment and disposed to be normal to the plane of the work. In Fig. 3 two consecutive bays of the machine are illustrated, and in the right-hand bay the supports 41, 51, are illustrated with the tools removed therefrom in order better to illustrate the supports.

The tool 1 is mounted ina gear case 6 attached to the support 4 and the gear case carries the devices, of known construction, for regulating the position of the tool 1 towards and away from the plane of the work, together 3 with an electric motor 7 which rotates the shaft 8 for tool 1. Similarly, the tool 2 is mounted in a gear case 9 attached to the support and the gear case 9 also supports an electric motor 10 to rotate the shaft 11 for tool 2, togethehr with the devices of known construction for regulating the position of the tool 2 towards and away from the plane of the world A curved metal plate 12 is movable with the support 4 and is provided to collect the mud containing abrasive or polishing material which is thrown off during the course of the work and is to protect the lower mechanism against contamination by such materials.

The support 4 for the lower tool 1 is provided with shoes 13, Fig. 3, which rest and slide on guide elements formed as tracks 14 forming part of angle irons 15 secured to horizontal girders 16 joining pillars 17 at opposite sides of the machine. The tracks 14 are disposed on opposite sides of the support 4 and are parallel to each other and to the plane of the work and are trans verse to the direction of movement of the work through the machine, being so disposed as to be normal to the direction of movement of the work.

Movement of the support along the tracks 14 is effected by an electric motor 18 mounted on the support and transmitting motion through a chain 19 to a shaft 20 provided with screw threads which mesh with a toothed wheel 21 keyed to a shaft 22. The shaft 22; is supported in bearings 23 and at its ends is provided with screw threads 24 meshing with toothed Wheels 25 secured to shafts 26. Secured to the shafts 26 are toothed pinions 27 which mesh with toothed racks 28 secured to the angle irons 1S and extending lengthwise thereof. The gear trains connecting the motor 18 with the racks 28 are reduction trains so arranged that the transverse movements imparted to the support 4 are slow as compared with the rate of rotation of the tool 1 supported thereby and reversing switches described below control the direction of rotation of the motor 18 so that the support is oscillated along the tracks 14 to obtain, as described above, a rubbing action of the tool which is the resultant of the rotary movement thereof and of the oscillatory movement in the path transverse to the direction of movement of the work.

When it is desired to effect servicing or replacement of the tool 1 the motor 18 is controlled in a manner such that it causes the support 4 to move in one direction beyond its normal stroke of oscillation until the gear case 6 thereon is moved to the position 62 indicated in broken lines in Fig. 1. During such movement, owing to the tools 1, 2 being mounted in independent supports, the upper tool 2 remains in working position above the work and it is possible at the position 62 to obtain free access to the lower tool 1 without the necessity of first dismantling the upper tool 2. If desired when the lower tool 1 is moved to the servicing position 62 a chassis as described in the aforesaid United States specification No. 2,508,863 having a work supporting plane may be made to slide progressively below the work, to support the work during the absence of the tool 1 from its working position so that operation of the machine can continue without interruption.

The transverse movement of the support 5 for the upper tool 2 is effected in a manner similar to that described above with reference to the lower tool by mechanism about to be described which operates in the same way as that for the lower tool. To this end, an electric motor 29 is mounted on the support 5 and, through a chain 30, drives a shaft 3-1, Pigv 3, provided with screw threads which mesh with a toothed wheel 32 keyed to a shaft 33. The shaft 33 is supported in bearings 34 on the support 5 and at its ends is provided with screw threads 35 meshing with toothed wheels 36 keyed to two vertical shafts 37. Secured to the shafts 37 are toothed pinions 38 which mesh with toothed racks 39 secured to horizontal box girders 40 connecting pillars 41 at opposite sides of the machine, the pillars 41 comprising continuations of the pillars 17 mentioned above. The support 5 is provided with shoes which rest and slide on guide elements formed as tracks 42 secured to the upper faces of the box girders 40. As in the case of the motor 18, reversing switches control the direction of rotation of the motor 29 and determine the stroke of oscillation of the support 5 along the tracks 42.

Fig. 4 is a circuit diagram illustrating one mode of effecting operation of the motors 18, 29. The supports 4, 5 are provided respectively with pins 43, 44 normally movable by the supports in the gap formed between the arms of rocking switch members 45, 46 pivoted at 47, 43 respectively. The rocking members carry switch elements 49, 50 of which the element 49 co-operates with a forward contact 51 or a reverse contact 52 according to the direction of movement of the support 4 and the element 50 co-operates with similar contacts 53, 54 according to the direction of movement of the support 5.

In operation, when the supports 4, 5 are moving forward the switch elements 49, 5d engage contacts 51, 53 so that the forward contacts of contactors 55, 56 for motors 18, 29 are closed through solenoids 57, 58. On reaching the ends of their strokes the supports 4, 5 through pins 43, 44 tip switch members 49, 59 so that contacts 52, 54 are engaged thereby thus exciting solenoids 59, 6t! which in turn close the reverse contacts of contactors 55, 56, the forward contacts of which are opened on disengagement of switch elements 49, 50 from contacts 51, 53. Accordingly the motors are reversed and the supports 4, 5 move along their return stroke.

When it is desired to move a support to the servicing position thereof this is effected by a two position, double pole, lock and free push button switch 61 or 62 having one set of contacts normally open and one set normally closed. Thus if the support 4 is to be moved to servicing position the push button switch 61 is operated thereby cutting out the automatic circuit and exciting solenoid 59 so that the motor 18 then moves the support to servicing position, the pin 43 on support 4 being moved away from the switch member 45. To return the support to working position a second push button switch 63 is pressed exciting the solenoid 57 so that the motor 18 returns the support and pin to their working positions. A second push button switch 64, which is connected in the same manner as push button switch 63, is provided for support 5. 1

From the foregoing it will be understood that, owing to the upper tool 2 being mounted in a support 5' independent of the support 4 for the lower tool 1, when the upper tool is moved to the servicing position 52, Pig. 1, the lower tool 1 remains in its working position and, accordingly, continues to support the work during servic ing of the upper tool 2, so that operation of the machine can continue without interruption.

Usually during the operation of the pair of tools the upper and lower tool of the pair are maintained substantially in axial alignment. If desired, however, the motors l8 and 29- may be so driven that during their operation to effect oscillation of the supports 4, 5 along the tracks 14, 42 the movements of the supports are effected in opposite directions. This can be etiected, as will be readily understood, by the circuit shown in Fig. 4.

The apparatus described above comprises a preferred embodiment of the invention but it will be understood that other ways of carrying the invention into effect may be employed within the terms of the claims appended hereto.

I claim:

1. Apparatus for operating on a continuously moving ribbon of glass, comprising a plurality of co-axial pairs of tools of which the tools of each pair co-act to operate simultaneously on the two surfaces of the ribbon, pairs of driving rolls between said pairs of co-axial tools to drive the ribbon between the tools of each pair, an individual travelling support for each tool of a pair disposing the respective tool for rotation in a plane parallel with the path through which the ribbon is moved by the driving rolls, a first motor carried by each said support to efiect operative rotation of the tool carried thereby, a pair of linear tracks individual to each said support disposed in spaced relation to permit lateral movement of the support therebetween, traversing means carried by each support co-operating with each of the respective tracks to effect lateral movement of the support along said tracks, a reversible second motor carrled by each said support and reduction gearing connecting the reversible motor with the traversing means to produce relatively slow lateral movement of the supports as compared with the rate of rotation of the tools carried thereby.

2. Apparatus according to claim 1, wherein each track carries a toothed rack extending lengthwise of and inwards of the respective track pair, and the traversing means for each tool comprises a pair of pinions journalled in the respective tool support and disposed to mesh with the respective track pair, the associated reduction gear actuated by the reversible motor driving the said pair of pinions.

3. In apparatus for grinding or polishing simultaneously the two surfaces of a continuous ribbon of glass including co-axial pairs of tools, the tools of a pair co-acting to operate simultaneously on the two surfaces of the ribbon and means for advancing the ribbon between the co-operating pairs of tools, an individual travelling support for each tool, a framework, pairs of parallel tracks, one pair for each travelling support, said tracks being fixed in the frame-work at right angles to the direction of movement of the ribbon, a first motor carried by each tool support to effect operative rotation of the tool, traversing means carried by each support co-operating with the associated pair of tracks to effect lateral movement of the support along its pair of tracks as the respective tool rotates, a reversing motor carried by each support and reduction gearing connecting the reversing motor with the traversing means to produce a relatively slow movement of the support along its tracks, as compared with the rate of rotation of the tool, and switch means for controlling the operation of the reversing motor.

4. Apparatus according to claim 3, wherein the pair of tracks are of a length such that each tool may traverse the ribbon in operative relation therewith and be moved beyond the ribbon to a servicing position.

References Cited in the file of this patent UNITED STATES PATENTS 1,474,672 Heuze Nov. 20, 1923 1,684,029 Howard Sept. 11, 1928 1,803,752 Ford May 5, 1931 2,176,481 Waldron et al. Oct. 17, 1939 2,398,556 Pearson Apr. 16, 1946 2,508,863 Labby et al. May 23, 1950

Claims (1)

1. APPARATUS FOR OPERATING ON A CONTINUOUSLY MOVING RIBBON OF GLASS, COMPRISING A PLURALITY OF CO-AXIAL PAIRS OF TOOLS OF WHICH THE TOOLS OF EACH PAIR CO-ACT TO OPERATE SIMULTANEOUSLY ON THE TWO SURFACES OF THE RIBBON, PAIRS OF DRIVING ROLLS BETWEEN SAID PAIRS OF CO-AXIAL TOOLS TO DRIVE THE RIBBON BETWEEN THE TOOLS OF EACH PAIR, AND INDIVIDUAL TRAVELLING SUPPORT FOR EACH TOOL OF A PAIR DISPOSING THE RESPECTIVE TOOL FOR ROTATION IN A PLANE PARALLEL WITH THE PATH THROUGH WHICH RIBBON IS MOVED BY THE DRIVING ROLLS, A FIRST MOTOR CARRIED BY EACH SAID SUPPORT TO EFFECT OPERATIVE ROTATION OF THE TOOL CARRIED THEREBY, A PAIR OF LINEAR TRACKS INDIVIDUAL TO EACH SAID SUPPORT DISPOSED IN SPACED RELATION TO PERMIT LATERAL MOVEMENT OF THE SUPPORT THEREBETWEEN, TRAVERSING MEANS CARRIED BY EACH SUPPORT CO-OPERATING WITH EACH OF THE RESPECTIVE TRACKS TO EFFECT LATERAL MOVEMENT OF THE SUPPORT ALONG SAID TRACKS, A REVERSIBLE SECOND MOTOR CARRIED BY EACH SAID SUPPORT AND REDUCTION GEARING CONNECTING THE REVERSIBLE MOTOR WITH THE TRAVERSING MEANS TO PRODUCE RELATIVELY SLOW LATERAL MOVEMENT OF THE SUPPORTS AS COMPARED WITH THE RATE OF ROTATION OF THE TOOLS CARRIED THEREBY.

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