US3353304A

US3353304A - Surface treatment of glass and apparatus therefor

Info

Publication number: US3353304A
Application number: US463248A
Authority: US
Inventors: Chaumont Henri Jules
Original assignee: Compagnie de Saint Gobain SA
Current assignee: Compagnie de Saint Gobain SA
Priority date: 1964-07-15
Filing date: 1965-06-11
Publication date: 1967-11-21
Anticipated expiration: 1984-11-21
Also published as: FR1409372A

Description

Nov. 21, 1967 CHAUMQNT 3,353,304

' SURFACE TREATMENT OF GLASS AND APPARATUS THEREFOR Filed June 11, 1965 2 Sheets-Shet 1 HEN/e/ JUL 5 O/AI/Mm/T 32 @MMW Nov. 21, 1967 H- J. CHAUMONT SURFACE TREATMENT OF GLASS AND APPARATUS THEREFOR Filed June 11, 1965 '2 Sheets-Sheet 2 United States Patent Office 3,353,304 Patented Nov. 21, 11967 13 Claims. (cl. 51-119 The present invention relates to the grinding and polishing of sheet glass by means of pads which are positively moved relatively to the sheet while in contact therewith. More particularly the invention relates to the situation wherein the grinding or polishing is effected by pads which move in a predetermined orbital or like path while the sheet of glass moves horizontally in the direction of its length between them.

It is a purpose of the invention to provide a device of the character aforesaid, wherein the movement of each surfacing pad is effected by two separate parts or cranks moved in synchronism with identical movements or rotations.

Another object is to provide an apparatus wherein the pad is connected with two power-driven blocks through a linking structure which provides a limited freedom of expansion or contraction between said blocks.

Another object is to provide an apparatus wherein the pad is connected with its power-driven operating means, through an articulated system or links which, while effecting positive movement of the pad directly in accordance with the corresponding movement of the powerdriven cranks, at the same time permits free movement of the pad toward and from the work, in a direction normal to the surface of the sheet so that force applied to the pad in the aforesaid direction is directly and fully applied to the work, resulting in uniform pressure of the pad upon the surface of the sheet.

A further object in accordance with that of the preceding paragraph, is the provision of an apparatus wherein the pad is free to move normal to the surface of the sheet so that it remains in full surface contact therewith and engages the sheet with even and uniform pressure until the applied forces are manually or automatically changed.

Another object is to provide an apparatus as aforesaid which assures the precise and accurate execution of the orbital or other desired motion of the grinding or polishing pad at all times, under all conditions of use, and irrespective of the particular value of the pressure of the pad upon the sheet, while allowing free manual of surfacing machines and which accurately transmits and reproduces the motion of its power-driven mechanism to the surfacing plate or frame and the pad carried v thereby.

The foregoing and other objects and advantages are attained by a system of three links and two cranks or other mechanical means for initiating the desired orbital movement. The first or central of the three links is pivoted on a first axis to the polishing pad plate or frame. The second link is articulated at one end to a corresponding end of the first link and at its other end to one of the cranks, while the third link is articulated at one end to the other end of the first link and at its other end to the other crank. Other links are used to effect direct connection between the cranks and pad frame to assure that the pad accurately and positively reproduces the orbital or translatory movements of the driving means. The resulting structure is indeformable in a plane parallel with the surface of the sheet, but readily permits or adapts itself automatically to movements normal to said plane.

The structure will further permit and adapt itself to accidental limited variations of the distance between the two power-driven means, such as would occur because of heat-expansion of the supporting frame or of a slight variation in the synchronism of these means.

Furthermore, because of the novel construction, the two cranks or other power-driven moving means impart equal forces to the linkage, so that there is no resultant force which might otherwise tend to distort or deform the same. Nor is there any resultant force developed by the linkage normal to the plane of the sheet. As a result, the operation is smooth, even and uniform. Pressure is uniform over the area of the pad and can be accurately gaged to assure a superior and accurately finished surface on both faces of the sheet.

The invention will be readily understood from a study of the following detailed description, in connection with the accompanying drawing.

In the drawing:

FIGURE 1 is a perspective view showing one embodiment of the invention;

FIGURE 2 is a side elevation showing a construction in which the pad is arranged for surfacing the lower surface of the sheet of glass, and depicting the three interpivoted links forming an important feature of the invention;

FIGURE 3 is a cross section in a plane identified by line ?i3, FIGURE 2, looking in the direction of the arrows;

and

FIGURE 4 is a plan view of the apparatus of FIG- URES 2 and 3, as seen from above.

Referring more particularly to FIGURE 1, 1 and 2 represent first and second driving elements shown in the form of rectangular or square thrust blocks each driven by a respective one of a pair of vertically-disposed

crankshafts

1a and 2a. The crank of shaft 1a is journaled t0 element 1 by an antifriction bearing 1b. A corresponding bearing 2b connects the crank of shaft 2a to and centrally of element or block 2. The cranks have equal throws and the shafts are so arranged, interconnected and driven, that their crank radii are at all times parallel. Any suitable means such as gears, chain and sprockets, shafts and bevel gearing, etc, may be provided to interconnect the two shafts for synchronous rotation in the same direction.

At 10 there is identified a rectangular plate, beam or frame, to the under side of which, in a known way, a polishing pad 17, FIGURES -2 and 3, may be attached.

A U-shaped bracket 9 has its central or bight portion secured at 10a centrally to the face of frame 10 opposite to that to which the pad is attached. A first link 5 has aligned trunnions 5a extending from its central portion. These trunnions are pivoted at 8' in the ends of the upstanding arms of bracket 9 so that the link is pivotable about an axis parallel with frame 10 and, when the device is operating, parallel with the surface of the sheet of glass being worked..A second link 3 has one end pivotally connected to element 2 at 6, and its other end pivoted to the adjacent end of link 5 at 3a. A third link 4 has one ribbed for greater rigidity. Links 3 and 4 are formed with forked ends. Referring to link 3, one forked end thereof embraces the contiguous end of link 5 and a pivot pin not shown, passes through aligned holes in the two links. Likewise the other forked end of link 3 embraces a pierced lug 6a integrally attached to one side edge of element 2, and a second pivot pin passes through aligned holes in the lug and link.

Link 4 is essentially like link 3 in shape, size and effective length. Its pivotal connection with link may be a duplicate of that interconnecting links 3 and 5. However, element 1 has a lug 1c upstanding from its top surface as viewed upon FIGURE 1, and adjacent and parallel with one side edge thereof. This lug is pierced and a pivot pin passes through and is secured in the aligned holes of the lug and forced end of the link. The construction and arrangement are such that plates or elements 1 and 2 are normally coplanar despite a small angularity of link 5 with respect to the plane of frame 10. Thus links 3 and 4 While normally essentially parallel with the plane of frame '10 are at slightly different elevations thereabove.

The linkage thus described resists twisting of frame about a normally vertical axis, with respect to elements 1 and 2, as well as about a horizontal axis parallel with the longitudinal axis of the frame, but permits limited vertical displacements between the frame and elements without, however, varying the relation between the effective lengths of the links, that is, their lengths projected upon the plane of frame 10 or, in operation, upon the plane of the sheet of glass being surfaced.

In order to transmit to the frame and its pad, component movements of blocks -1 and 2 in the direction parallel with the plane of the frame, and transversely of its longitudinal axis, additional linkage connections are provided. Referring first to block 1, a notch 1d therein receives one end of a link 11 with a pivotal connection between them about an axis parallel with the longitudinal axis of the frame. A U-shaped bracket has its central bight portion rigidly attached at A to the upper surface of frame 10 adjacent one side edge thereof. The

upper ends of the arms of thisbracket are pivotally connected at "13 to the other end of link 11. A similar link 12 connects element 2 to frame 10; and since the connection is-a duplicate of the one just described, itwill be sufficient to identify bracket 16 secured at B to frame 10, line 12 pivoted at one end at 14 between the distal ends of the arms of bracket 16, and at its other end within notch of thrust block or element 2. It will be noted that the axial width of links 11 and 12 in and between the arms of

brackets

15 and 16, respectively, is a little less than the separation between the arms. Thus each link has a limited amount of axial movement or play between the arms of its bracket'to permit expansion due to heat and undue friction otherwise caused by such expansion.

FIGURES 2, 3 and 4 schematically illustrate the general arrangement of parts when the apparatus is disposed to Work upon the lower surface of the sheet of glass. In

thesefigures the thrust blocks '1 and 2, links 3, 4, 5, 11 and '12, and

brackets

9, 15 and 16 are related as previously described in connection with FIGURE 1. In FIGURE 2, bracket 15 and link '11 have been omitted to avoid obscuration of one of the thrust rods to be described.

In FIGURES ,2'and 3, 23 identifies generally a'base or frame of the machine and havingspaced vertically-disposed aperturesor guides 24 and 25 in which are mounted

casings

26 and 27, respectively. These casings may be hollow and contain the mechanism indicated at 1a and 2a,

respectively, FIGURE 1, to protect the same against damage from grinding compound, moisture, dust and dirt. The upper surfaces of these casings are fiat and coplanar, and each supports its block 1 and 2 for sliding on its surface'by and in response to rotation of

shafts

1a and 2a. It is contemplated that antifriction thrust bearings of known construction will be provided between the upper surface of each casing and its thrust block 1 or 2, as the case may be.

In the construction being described, means are provided to mechanically vary the elevation of pad frame 10 with respect to blocks 1 and'2. Thus, block 1 has a pair of transversely spaced lugs fixed to its upper face,

as the parts are viewed upon FIGURES 2 and 3, and forked to pivotally receive between them the respective ends of threaded

rods

21 and 30. Similarly, frame 10 has a pair of forked lugs 31, 32 fixed to its lower surface and forked to pivotally receive the ends of threaded

rods

20 and 33. All axes of pivotal connection, as between 21 and 28 for example, are normal to the plane of FIGURE 3. A turnbuckle 22

interconnects rods

20 and 21 so that, in the usual way, turning thereof in one direction or the other correspondingly varies the spacing of the frame with respect to the blocks. Likewise,

rods

30 and 33 are connected by turnbuckle 34 which may be actuated to similarly increase or decrease the separation of these rods. In this way the elevation of the continguous end of frame 10 above block 1 may be varied.

A similar pair of rods and turnbuckles adjustably connect block 2 and the other end of frame 10. Since these are duplicates of those described in the preceding para graph, it is suflicient, referring to FIGURES 2 and 4, to identify one turnbuckle 19, rods 35 and 36 connected thereby, and forked

lugs

37 and 38 fixed, respectively to block 2 and frame 10.

Thus, by equal rotations of all four turnbuckles a precise and fine adjustment may be effected, of the elevation of frame 10 with respect to blocks 1 and 2. It is contemplated that in addition to or in substitution for the aforesaid turnbuckle adjustment feature,

casings

26 and 27 may be made vertically adjustable each in its aperture '24, 25, with respect to frame 23. Such adjustment may be made by mechanically, pneumatically or hydraulically operated means, not shown. The adjustment thus provided for is within small limits and is compensated by a slight pivoting of links 3, 4, 5, 1-1 and '12 and which in no way affects the accuracy of operation of the invention. Referring to the component motion of the assembly in the direction parallel with the longitudinal axis of frame 10, it is noted that the forces applied by

shafts

1a and 2a necessary to produce this motion, are applied equally to link 5 by links 3 and 4, so that there is no tendency of this link to pivot in response to such forces. Thus, considering FIGURE 2, motion of link 4 to the right by force applied through block 1, tends to pivot link 5 clockwise, while motion of link 3 in the same direction as the result of force applied by block 2 tends to pivot link 5 counterclockwise. The two torques thus exerted upon link 5 annul one another and have no tendency to pivot it about axis 8. Changes in spacing between the blocks, on the one hand, and frame or plate 10 on the other, are automatically compensated by a slight relative pivoting between links 3, 4 and 5 without, however, any change in the orbital or other motion applied 'to the frame by

shafts

1a and 2a.

If the distance between blocks 1 and 2 is accidentally modified, links 3, 4 and 5 will pivot slightly and automatically'adjust themselves to the new distance separating blocks 1 and 2.

The operation will be clear from the foregoing description and is briefly rsumd. The sheet of glass on a conveyor notshown and moving continuously in the direction of its length is supported at a location in its travel, by one ormore of the frames 10 as depicted upon FIGURE 2, each equipped withapad 17 and continuously supplied by known means, with grinding or polishing compound. Likewise a second one or plurality of devices as in FIG- URE 1 'will be in contact with and operating upon the upper face of the sheet at the aforesaid location. The arrangement is such that the entire .area of the sheet Of glass on both faces thereof is worked upon 'by the pads. In the case of the pad contacting the upper face of the sheet, the weight of the frame may be assisted by hydraullically or pneumatically-operated means to exert a controlled downward thrust upon the frame in a manner similar to that applied by the turnbuckles of FIGURES 2, 3 and 4.

In a manner clear from inspection ofthe drawing and from the previous description, the component of motion of blocks 1 and 2 in the direction parallel to the longitudinal axis of frame is transmitted thereto by links 3, 4 and 5, through bracket 9. Similarly the component of motion parallel to the frame and normal to the longitudinal axis thereof, is transmitted by links 11 and 12 through

brackets

15 and 16, respectively. At the same time, necessary adjustments of the upper and lower frames relatively to the sheet are'manually or automatically effected without appreciable change in the motion of the frames. Such adjustments are from time to time made necessary by reduction in thickness of the sheet by removal of detritus, wear of the pads, variations in thickness of glass being processed, and other factors.

In the case of the lower frame whose pad is working upon the lower face of the sheet, adjustments are readily effected by turning of turn-buckles 22, 34, etc., or by varying the hydraulic

force urging casings

26, 27 upwardly, where such force-applying means are provided. In the case of the upper frame the weight of the frame, augmented by hydraulic or pneumatic force-applying means interposed between blocks 1 and 2 and the frame, provide automatically for full-area contact at all times between the pad and the sheet, and enable the pressure to be maintained at a constant value which may be increased or decreased as required by the particular operation being carried out, e.g., grinding or polishing, the compound used, type of glass, speed of movement of the sheet and numerous other considerations.

I have thus provided a device which fulfills all of the objects stated. Due to the uniformity of pressure of the pads upon the glass, and the precise control and automatic compensation afforded by the invention, rapid polishing and grinding operations are carried out with a resulting superior product having a perfection of smoothness and polish not previously attainable.

Since many alterations, modifications, substitutions of equivalents and changes in shape, size and form will readily occur to those skilled in the art, after a study of the foregoing description, the disclosure should be taken in an illustrative rather than a limiting sense. All modifications within the scope of the subjoined claims are reserved.

Having now fully disclosed the invention what I claim and desire to secure by Letters Patent is:

1. In an apparatus for surfacing sheet glass, a plate having a planar surface to which a pad may be attached for frictional contact with the sheet glass, a pair of thrust blocks, means operable to move said blocks in unison in a predetermined path having mutually-normal components parallel to said surface, first link means between said blocks and plate to transmit one of said components of motion to said plate, and second link means between said blocks and plate to transmit the other said component of motion to said plate.

2. A grinding and polishing apparatus for sheet glass, comprising, a plate having a planar surface to which a pad may be secured, and having mutually normal first and second axes in said surface, a pair of thrust blocks mounted in spaced relation along said first axis, a first link mounted on said plate for pivoting about an axis parallel with said second axis, second and third links each connected at one end to a respective one of said blocks and at its other end to a respective end of said first link, and power driven means engaging said blocks and operable to move the same and said plate in a predetermined path.

3. The apparatus of claim 2, said last-named means comprising a pair of parallel spaced shafts each having a crank at its end journaled to a respective one of said blocks.

4. An apparatus for surfacing a sheet of glass moving in the direction of its length, comprising, plate means having a planar surface over which a surfacing pad may be secured, first and second thrust blocks spaced along a first axis in said surface, a first link pivoted between its ends to said plate means, second and third links each pivoted at one end to a respective one of said blocks and at its other end to a respective end of said first link, all pivot axes of said first, second and third links being parallel with said surface and normal to said first axis, fourth and fifth links each pivoted at one end to a respective one of said blocks and at its other end to said plate means, the pivot axes of said fourth and fifth links being parallel to said first axis, and power-driven means connected with said blocks to move the same equally and in synchronism in a plane parallel with said surface.

5. The apparatu of claim 4, said second, third, fourth and fifth links being substantially parallel with said surface.

6. The apparatus of claim 4, said power-driven means comprising first and second shafts each mounted with its axis of rotation normal to said surface, each said shaft having a crank on its end journaled in a respective one of said thrust blocks, said shafts being rotated in synchronism with their crank radii parallel.

7. Apparatus for surfacing sheet glass comprising, a frame having a planar surface to which a surfacing pad may be attached, first and second spaced thrust blocks, a first link, means pivoting said link between its ends to said frame, second and third links each having one end pivotally connected with a respective one of said blocks and its other end pivotally connected with a respective end of said first link, all pivot axes of said first, second and third links being parallel and parallel with said surface, fourth and fifth links each pivoted at one end to a respective one of said blocks and at its other end to said frame, the pivot axes of said fourth and fifth links being parallel with said surface and normal to the pivot axes of said first, second and third links, and thrust means between said frame and blocks and operable to vary the spacing therebetween.

8. The apparatus of claim 7, said last-named means comprising a first plurality of rods of adjustable length each pivoted at one end to said first block and at its other end to said frame, and a second plurality of rods of adjustable length each pivoted at one end to said frame and at its other end to said second block, the pivot axes of all said rods being parallel with the pivot axes of said fourth and fifth links.

9. The apparatus of claim 7, a base, and means carried by said base and supporting said blocks for translational adjustment in the direction normal to said planar surface.

10. An apparatus for surfacing sheet glass, comprising, a plate having a planar surface to and over which a surfacing pad may be secured, first, second and third bracket means rigid with said plate, first and second thrust blocks spaced in a first direction parallel with said surface, a first link pivoted between its ends in said first bracket means, second and third links each pivoted at one end to a respective one of said blocks and at its other end to a respective end of said first link, fourth and fifth links each pivoted at one end in a respective one of said second and third bracket means, and at its other end to a respective one of said blocks, said first link being inclined to said surface, said second, third, fourth and fifth links being essentially parallel with said surface, the pivot axes of said first, second and third links being parallel and normal to the parallel pivot axes of said fourth and fifth links, all said pivot axes being parallel with said surface, spaced parallel vertically disposed first and second crankshafts having equal crank radii, and means journaling the crank of each said shaft in a respective one of said blocks.

11. The apparatus of claim 10, and thrust rod means connected between each said block and said plate and operable to vary the separation therebetween.

12. A grinding and polishing apparatus for sheet glass comprising:

a plate having a planar surface to which a pad may be secured,

a pair of power-driven blocks operable in unison to move said plate in a predetermined path having mutually normal components parallel to said surface,

first link means between both said blocks and said plate to transmit one of said components of motion from said blocks to said plate and providing limited freedom of expansion between said blocks,

and second link means between each of said blocks and said plate, to transmit to said plate the other of said component of motion.

13. The apparatus of claim 12 and thrust means interposed between said blocks and said plate to urge said plate in contact with the surface of the sheet of glass.

References Cited UNITED STATES PATENTS 10 ROBERT C. RIORDON, Primary Examiner.

A. MATHEWS, Assistant Examiner.

Claims

1. IN AN APPARATUS FOR SURFACING SHEET GLASS, A PLATE HAVING A PLANAR SURFACE TO WHICH A PAD MAY BE ATTACHED FOR FRICTIONAL CONTACT WITH THE SHEET GLASS, A PAIR OF THRUST BLOCKS, MEANS OPERABLE TO MOVE SAID BLOCKS IN UNISON IN A PREDETERMINE PATH HAVING MUTUALLY-NORMAL COMPONENTS PARALLEL TO SAID SURFACE, FIRST LINK MEANS BETWEEN SAID BLOCKS AND PLATE TO TRANSMIT ONE OF SAID COMPONENTS OF MOTION TO SAID PLATE, AND SECOND LINK MEANS BETWEEN SAID BLOCKS AND PLATE TO TRANSMIT THE OTHER SAID COMPONENT OF MOTION TO SAID PLATE.