US2886925A - Grinding and polishing table unlocking device - Google Patents

Description

May 19, 1959 FIG! v. s. FIRESTONE GRINDING AND POLISHING TABLE UNLOCKING DEVICE Filed Dec. 2, 1957 2 Sheets-Sheet 1 Fla. 2

:1) d BY E INVENTOR.

y 19, 1959 .v. s. FIRESTONE GRINDING AND POLISHING TABLE UNLOCKING DEVICE Filed Dec. 2, 1957 2 Shets-Sheet 2 I INVENTOR. m/vae' .s. F/AE'Sfd/V' arrow/5x GRINDING AND POLISHENG TABLE UNLOCKING DEVICE Vance S. Firestone, Ford City, Pa., assignor to Pittsburgh Plate Glass Company, Allegheny County, Pa., a corporation of Pennsylvania Application December 2, 1957, Serial No. 700,211 Claims. (Cl. 51-240) This invention broadly relates to grinding and polishing plate glass, and more particularly to apparatus for automatically unlocking adjacent tables which support sheets of plate glass for grinding and polishing operations.

In the manufacture of polished plate glass, rough rolled glass is cut into discrete sheets and each sheet is embedded in plaster of Paris on a wheeled table adapted to run on tracks along a grinding and polishing line. Adjacent tables are locked together to present the sheets of glass to the grinding and polishing runners. At the end of the grinding and polishing line the end table is unlocked from the adjacent table and the glass sheet thereon is removed, thereby making the table available for receiving another sheet to be ground and polished through the line. Heretofore, the unlocking of the end table from the adjacent one has been manually done, a relatively dangerous operation. The present invention provides apparatus for dispensing with the manual unlocking of adjacent tables,

the apparatus being constructed in such a manner that the unlocking of the tables occurs at the end of the grinding and polishing line under the control of the tables as they move toward the end of the line.

Therefore, the primary object of this invention is the provision of apparatus for unlocking adjacent grinding and polishing tables.

Another object of this invention is the provision of apparatus for automatically unlocking an end table in a grinding and polishing line from an adjacent table, the unlocking being controlled by the tables as they move toward the end of the line.

These and other objects and features of this invention will be apparent from the following description when taken with the accompanying drawings in which:

Figure l is an elevational view showing grinding and polishing tables and the mechanism for unlocking adjacent tables;

Figure 2 is a sectional partial view of the apparatus of Figure 1 taken on line 22 of Figure l and reduced in size;

Figure 3 is a sectional partial View of the apparatus of Figure 1 taken on line 3-3 of Figure 1 and reduced in size;

Figure 4 is an enlarged view, partially in section, showing the locking means; and

Figure 5 is a schematic illustration of the pneumatic system of this invention.

Referring to the drawings, and especially to Figures 1, 2 and 3, there is illustrated a plurality of grinding and polishing tables locked together for movement to the left, as viewed in Figure l, for receiving and conveying plate glass sheets along the line, the tables shown being adjacent the end of the grinding and polishing line and being identified, for purposes of description as 10A, 10B and 100, the table 10C being the last one in the line and being described as the one unlocked from the line. The tables 10 are identical and of suitable channel construction having transverse webs, as may be easily viewed in Figure 4. The tables 10 are each provided with the itedl States Patent 0 usual wheels, not illustrated for the sake of clarity, which run on longitudinal tracks 12 supported above the floor by means of longitudinal I beams 14, (see Figures 2 and 3). The adjacent tables 10 are locked to one another by means of a locking mechanism, generally identified by r the reference character 16, and shown in detail in Figure 4.

Each locking mechanism 16 comprises a portion received within the trailing end of a table 10 and a cooperating portion received within the leading end of a table 10. The parts to be described are preferably duplicated transversely of the table and, since their construction is identical, one description will suflice. The portion of the locking mechanism received in the trailing end of a table includes a latching jaw element 18 resiliently mounted for limited longitudinal movement and having an upstanding engaging flange or jaw 19 extending beyond the end of the table for cooperation with the portion received within the leading edge of the adjacent table. The latching element 18 is provided with a jaw insert 20 attachedto the engaging flange 19, the outer extremity of which is provided with a curved surface thereon. The element 18 is attached or made integral with a longitudinally disposed threaded rod 22 supported for sliding motion by means of spaced, cylindrical bushings 24 and 26. The bushings 24 and 26 are retained within a housing 28 fixed within the table 10 and provide a cavity 30 to receive resilient means in the form of a pair of relatively strong compression springs 32 and 34. The compression springs 32 and 34 surround the rod 22 and are positioned between a wall of the housing 28 and a substantial- 1y cylindrical spring stop 36 threadably received on the rod 22. The resilient means urge the element 18 toward the right, as illustrated in Figure 4, and the resilient force may be adjusted by moving the spring stop 36 to the right or to the left. In the actual construction the physical size of the resilient means dictates the use of a pair of compression springs, but it is to be understood that a sufficiently strong single spring could be used without departing from the spirit of this invention.

The portion of the locking mechanism 16 received within the leading end of the table 10 includes a latching jaw element 38 having a depending engaging flange or jaw 39 to which is fixed a jaw insert 40. The insert 40, like the jaw insert 20, is provided with a curved surface adapted to cooperate with the jaw 20 carried. by the locking element 18 when the adjacent tables are locked together as indicated in full lines in Figure 4. The curved surfaces of the jaw 20 and 40 allow smoother engagement and disengagement of the latching elements 18 and 38, as will be apparent to one skilled in the art. The latching element 38 is suitably fixed, as illustrated, to a transversely extending shaft 42 rotatably journaled in spaced substantially cylindrical bushings 44 carried by the table 10 in any conventional manner.

An operating arm 46 rotatably carrying a roller 48 at its lower terminal end is provided for moving the latching elements 18 and 38 into and out of their latching position so that, as illustrated in Figure 4, when the arm 46 is in its full line position the adjacent tables 10 are locked together, and when the arm 46 is in its dotted line position the latching elements 18 and 38 are disengaged and the adjacent tables are unlocked from one another. The arm 46 is eccentrically fixed to the shaft 42 in such a manner that a central longitudinal axis thereof passes through an axis 50 of the shaft 42, the axis 50 being displaced from the major axis 52. The displacement of the axes 50 and 52 allow the arm 46 to move through a much greater are than that of the latching element 38, this being apparent from the full and dotted line positions of the arm 46 and the full and dotted line positions of the element 38, as illustrated a in Figure 4. The rotation of the latching element 38 is limited by stop surfaces 54 and 56, and the rotation of the arm 46 is limited by stop surfaces 58 and 60. The stop surfaces just described are defined on a casting 62 suitably connected within the table 10.

A. pair of spaced limit switches 64 and 66 are supported beyond the sides of the tables 10 along the path of movement of the tables and the switches are provided with depending switch levers 68 and 70, respectively. A vertically disposed and movable cam rod 72 having a cam surface 74 thereon is provided for actuating the limit switch 64 by allowing the switch lever 68 to move off the cam surface 74. The cam rod 72 is pivotally connected to a link 76 fixed to a transversely extending shaft 78, the shaft 78 being rotatably supported in spaced bearings 80, as illustrated in Figure 2. Operating levers 82 are fixed to the shaft 73 in transverse alignment with the arms 46, previously described, and such levers may be provided with hardened wear surfaces, such as shown in Figure 1, if desired.

In a like manner a vertically disposed and movable cam rod 84 having a cam surface 86 thereon is provided for actuating the limit switch 66 by allowing the switch lever 70 to move off the cam surface 36. The cam rod 84 is pivotably connected to a link 88 fixed to a transversely extending shaft itl supported in spaced bearings (not shown) which are similar to the bearings 80. Operating levers 92 are fixed to the shaft in transverse alignment with the arms 46 and the levers may be provided with hardened wear surfaces, if desired.

A truck or sled 94 disposed for limited rolling motion on spaced rails 96 is positioned beneath the tables 10 near the end of the line, and the truck 9 is provided with a suitably journaled rotatable shaft 98 to which is fixed bars or the like 100 for cooperation with the arms 46. Counterweights 102 disposed adjacent the outer side extremities of the truck 94 are also fixed to the shaft 88, and stop means 104 are provided on the truck or sled 94. The counterweights 102 position the bars 100 in the manner illustrated in Figure 1, and abut the stops 104 when the bars 100 are so positioned. This construction allows the bars 100 to freely rotate in a counterclockwise direction, (as viewed in the drawing), as when the arms 46 move past the truck 4, and limit their moving in a clockwise direction by the counterweights 92 abutting the stops 94.

A double acting air cylinder 106 is supported on the rail 96 and its piston rod 108 is attached, as at 110, to the truck or sled 94. Thus, when air is introduced into one end of the cylinder 106, the truck 84 will be moved in one direction, and when air is introduced into the other end of the cylinder 106, the truck 94 will be moved in the opposite direction.

Attention is now directed to Figure 5 illustrating schematically the pneumatic system of this invention. Shown are the double acting air cylinders 106, an air pump 112 of conventional design, solenoid valves 11 and 116 adapted to be actuated in a manner to be described by the limit switches 64 and 66, respectively, and conduit, hoses or the like 118, 120, 122, 124, 126, 123, 130, 132 and 134.

The conduit 11% is connected to the pump 112 and to each of the valves 114 and 116; the conduit 126 is connected to the valve 114 and to the conduit 122, which in turn connects the rear ends of the cylinders 166; the conduit 124 connects the front ends of the cylinders 106 and is connected to the conduit 126; the conduit 128 is connected to the conduit 126 and to each of the valves 114 and 116; the conduit 13% is connected to the conduit 120 and to the valve 116; and the conduits 132 and 134 are exhaust conduits for the valves 114 and 116, respectively.

With the limit switches 64 and 66 inactivated (as is the switch 66 shown in Figure l), the solenoid valves 114 and 116 are not energized. The solenoid valves are .4 so constructed that when not energized, the conduits connected thereto will be blocked and no air flows therein. The truck 94, at this time, is in its illustrated posi tion. As the table 10A moves past the limit switches 64 and 66, the arms 46 initially contact the levers 82 thereby rotating the shaft 78 and, through the link 76, moving the cam arm 72 vertically upwardly. This movement of the arm 72 allows the switch lever 68 to move off the cam surface 74, thereby energizing the solenoid valve 114. The energization of the solenoid valve 114 causes the connection of the conduits 113 and and the connection of the conduits 128 and 132. Air under pressure from the pump 112 flows through the conduit 118 and through the conduits 120 and 122 into the rear ends of the cylinders 106, thereby moving the pistons and the connected truck 94 to the left, as viewed in Figure l. The bars 100 on the truck 94 contact the arms 46 associated with the locking mechanism 16 on the table 1013 directly over the truck 94, and move the arms 46 to their dotted line position, thus unlocking the last table 10C from the line. At the same time, trapped air in the front ends of the cylinders 106 exhausts through the conduits 124, 126, 128 and 132.

Further movement of the table 10A brings the arms 46 into engagement with the levers 92 associated with the limit switch 66, which is activated in the same manner as the limit switch 64. However, activation of the limit switch 66 energizes the solenoid valve 116, so as to cause the connection of the conduits 118 and 128 and the connection of the conduits 130 and 134. Thus, air under pressure flows through the conduits 128, 126 and 124 into the front ends of the cylinders 106 to act against the pistons and return the truck 94 to its illustrated position for a subsequent unlocking operation. At the same time, air in the rear ends of the cylinders 106 is exhausted through the conduits 122, 130 and 134. When the table 10A passes the limit switch 66, the switch is inactivated which deenergizes the solenoid valve 116, thus completing an operating cycle.

While this invention has been described with reference to one embodiment, it is to be understood that this is by way of illustration and not limitation.

I claim:

1. In plate glass grinding and polishing apparatus, the combination of a plurality of tables for supporting and conveying sheets of glass along a grinding and polishing line and having a path of movement along the line, latching means for connecting adjacent tables together and adapted to be unlatched near the end of the line thereby freeing the end table from its adjacent table, said latching means comprising a first jaw member connected to each table adjacent at one end and a second cooperating jaw member connected to each table adjacent the opposite end whereby a first jaw member of one table engages a second cooperating jaw member of an adjacent table when the tables are latched together, means mounting the first jaw members for limited arcuate movement from a latching position to an unlatching position, an arm connected to each of said first jaw members, means mounting each of said arms for limited arcuate movement from a latching position to an unlatching position corresponding to the positions of said first jaw members, and means to move each of said arms from its latching position to its unlatching position thereby also moving a connected first jaw member from its latching position to its unlatching position, said moving means including an air cylinder and means to supply air to the opposite ends of said cylinder to thereby move said moving means to and from a position for moving said arm and being located adjacent the end of the line so as to cause the unlatching of the end table from its adjacent table, and means located along the path of movement for actuating said moving means.

2. Plate glass grinding and polishing apparatus, as

recited in claim 1, wherein "said means to supply air to the opposite ends of said cylinder are solenoid valves.

3. Plate glass grinding and polishing apparatus, as recited in claim 2, wherein said actuating means are spaced limit switches for energizing said solenoid valves and further including arm means operatively associated with said tables for operating said limit switches.

4. Plate glass grinding and polishing apparatus, as recited in claim 3, wherein one of said limit switches is so constructed and arranged to energize one of said solenoid valves to supply air to one end of said cylinder to move said moving means and said arm to its unlatching position and another of said limit switches is so constructed and arranged to supply air to the opposite end of said cylinder to move said moving means to a position of rest.

5. In apparatus for grinding and polishing plate glass, the combination of a plurality of tables for supporting and conveying sheets of glass along a grinding and polishing line and having a path of movement along the line, interengaging locking means operatively associated with said tables for locking adjacent tables together, an arm operatively connected to said locking means and movable in one direction to unlock said locking means, an air cylinder located adjacent the end of the line for moving said arm in said one direction to unlock said locking means and thereby unlock a table from an adjacent table upon its arrival at the end of the line, a source of air under pressure, a valve for controlling the flow of air from said source to said cylinder, and means located along said path of movement actuated by said arm for actuating said valve to provide a flow of air from said source to said cylinder to move said arm in said one direction.

References Cited in the file of this patent UNITED STATES PATENTS 1,679,472 Hitchcock Aug. 7, 1928 1,861,659 Fox June 7, 1932 1,901,511 Handy Mar. 14, 1933 1,913,994 Price June 13, 1933

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