US2845755A - Selective control devices for disc grinders - Google Patents

Description

R. E. PRICE 2,845,755

SELECTIVE CONTROL DEVICES FOR msc GRINDERS Aug; 5, 1958 Filed Nov. 9, 1956 5 M RR Y m flw z m mH/ m A 2 A e B \T) Q S, \w M.

d. a m R4 SELECTIVE CONTROL DEVICES FOR DISC GRINDERS Ralph E. Price, Beloit, Wis., assignor to Gardner Machine Company, Beloit, Wis.

Application November 9, 1956, Serial No. 621,419

5 Claims. (Cl. 51--112) This invention relates to disc grinders, particularly to size control devices for such machines.

An object of this invention is to provide measuring devices directed against opposite sides of a workpiece as it emerges from between opposed grinding discs for determining which requires adjustment for wear as indicated by oversize condition of the work.

In the drawing, numerals 11a and 11b indicate supporting members for annularly opposed abrasive discs 13a and 13b. The hydraulic motor consisting of cylinders 40a and 40b serve to retract discs 13a and 13b from grinding position. Another motor consists of cylinders 60a and 60b and pistons 62a and 62b which actuate two levers 70a and 70b to move said abrasive discs toward one another. The head ends of each of said cylinders is always under constant air pressure.

Means is also provided for effecting incremental movement of each of said discs including a motor having cylinders 30a and 30b and pistons 32a and 32b for actuating pawls 28a and 28b and ratchets 27a and 27b. Said ratchets function through suitable gearing to rotate feed screws 21a and 21b to advance said abrasive discs toward one another. The means for selectively controlling the flow of actuating fluid to opposite ends of cylinders 30:: and 30b consists of a pair of oppositely disposed nozzles 45 and 46 adjacent the point of exit of the workpiece from between the grinding discs. A supply of air for said nozzles 45 and 46, which is provided through pressure regulating valves PR3 and PR2. respectively, is also connected to pressure switches PS3 and PS2 respectively. As the workpieces emerge from the grinding discs and move past said nozzles, they enter a space between guide members 51 and 52. After passing through said guide members, the workpieces must pass a gauging device consisting of a stationary member 55 and a movable plunger member 56 of conventional construction for controlling the escape of air in accordance with the space between said members which is also the size of the workpiece. Said plunger member 56 is connected through a regulating valve PR1 to a supply of air which also acts on the air pressure switch PS1 when the escape of air from said plunger 56 is restricted.

Operation When a workpiece W emerges from between the grinding discs, it is checked by nozzles 45 and 46. If the workpiece is closer to one nozzle than the other, indicating oversize due to wear of the corresponding grinding disc, the air flowing from said nozzle will be restricted and the corresponding pressure switch will be actuated to rates Patent 6 close one of the contacts .53 or 54 in the circuit to one of the valve solenoids A or B. When said oversize workpiece passes between the members 55 and 56, the pressure operated switch PS1 is actuated to close a contact 57 to complete a circuit from L1 to contact 53 of pressure switch PS3 or contact 54 of pressure switch PS2. Closing PS3 or PS2 will complete a circuit to energize valve solenoids A or B to shift valves 3a or 3b to direct fluid under pressure to the rod end of cylinders 30a or 3011. Pistons 32a or 32b through piston rods 28:: or 28b and ratchets 27a or 27b will rotate feed screws 21a or 21b to advance discs 13a or 13b in the direction of the other whereby to restore the operating surfaces of the discs to alignment with guides 51 and 52 and spaced apart a distance equal to the desired thickness or size of the workpiece.

If a workpiece surface is not sufficiently out of line to actuate either of the pressure switches PS2 or PS3 as it passes between the nozzles 45 and 46, it may still cause an adjustment of one of the discs when it passes through the gauge members 55 and 56 since this gauge is more sensitive than the nozzles.

If neither of the nozzles transmits a signal, there is no selection as to which disc is to be fed. However, under these circumstances, any signal for feeding transmitted from the gauge member 56 acts to close contact 57 and complete a circuit from L1 through the normally closed contact 54 of PS2 to energize valve solenoid A and direct fluid under pressure through valve 3:: to the rod end of cylinder 30a to effect a feeding movement of wheel support 11a and disc 13a toward the opposing disc 13b. This intermittent feeding of disc 13a will continue until the nozzles 45 or 46 indicate an out of alignment condition sufiicient to cause nozzle 46 to actuate pressure switch PS2 to close a contact in the line leading to valve solenoid B. Thus, when the slightly oversize workpiece passes through the gauge members 55 and 56, a circuit will be completed through contact 57 of PS1 and normally closed contact 54 of PS2 to said solenoid to shift valve 3a and direct fluid under pressure to the rod end of cylinder 30a. Piston 32a actuates ratchet 27a to turn feed screw 21a to provide one or more increments of feed to disc 13a to restore the normal relation between the discs and the centerline of the workpiece and the guide surfaces and thus assure proper size of the ground workpiece.

If both discs 13a and 13b are worn sufficiently, the position of the workpiece surfaces as the workpiece emerges from between said discs, will be such as to restrict the air from both of the nozzles 45 and 46. This will close contacts 53 and 54 so that when the work passes between members 55 and 56, contact 57 of pressure switch PS1 will complete the circuit through both of the contacts 53 and 54 to energize valve solenoids A and B. Valves 3a and 3b will thus be shifted to direct fluid under pressure to the lower ends of cylinders 30a and 30b. Pistons 32a and 32b, through piston rods 28a and 28b and ratchets 27a and 27b, will rotate feed screws 21a and 21b to advance discs 13a and 13b toward one another whereby to restore the operating surfaces 'of said discs to alignment with guides 51 and 52.

I claim:

1. In a disc grinder having annularly opposed grinding discs, guide plates for guiding a workpiece as it emerges from between said discs, means for feeding each of said discs toward and from the other, control means on both sides of a workpiece as it emerges from between the grinding discs, said means serving to determine whether either or both sides of a workpiece is in proper alignment with said guides and hence, whether either or both of said discs requires adjustment, means actuated by said control means for effecting actuation of said feeding means to adjust one or both of said discs axially, a second control 3 element co-acting with one side of a workpiece to detect oversize workpieces, means actuated by the second control element for completing a circuit to one or both of said feed actuating control means depending upon whether one or both discs require adjustment.

2. In a disc grinder having annularly opposed grinding discs, each having means for feeding one toward and from the other, control means at both sides of a workpiece and responsive to the position of the work surface while part of said surface is still being ground, said means serving to determine whether one or both sides of a workpiece is in proper alignment and thus whether the discs are properly spaced and positioned, means actuated by said control means for effecting operation of said feeding means to adjust one or both of said discs axially, a second control element co-acting with a workpiece and positioned to be affected by the workpiece only after said workpiece has emerged completely from between the grinding discs to detect oversize workpieces, and means actuated by the second control element for completing a circuit to one or both of said feed actuating control means after said workpiece is clear of the grinding discs.

3. In a disc grinder having annularly opposed grinding discs, each having means for feeding one toward and from the other, a carrier for transporting workpieces between said opposed discs for a grinding operation, guide means in alignment with said grinding discs for receiving workpieces as they emerge from between said discs, a control device having elements for coacting with opposite sides of a workpiece while part of said workpiece is still being ground, such control means serving to determine whether either or both of said discs is worn beyond prescribed limits as evidenced by the lateral position and size of the emerging workpiece, means actuated by said control means for effecting operation of said feeding means to adjust one or both of said discs axially, a second control device co-acting with the workpieces immediately after they have passed said first control means and responsive to oversize of workpieces to co-operate with said first mentioned control means to actuate the feeding means for one or both of said grinding discs depending upon whether said first control means indicates the need for such adjustment by one or both of said discs.

4. In a disc grinder having annularly opposed grinding discs, each having means for feeding one toward and from the other, control means at both sides of a workpiece and responsive to the position of the work surface while part of said surface is still being ground, said means serving to determine whether one or both sides of a workpiece is in proper alignment and thus whether the discs are properly spaced and positioned, means actuated by said control means for effecting operation of said feeding means to adjust one or both of said discs axially, a second control element co-acting with a workpiece for detecting oversized workpieces and positioned so that a workpiece will pass therethrough only after said workpiece has emerged completely from between the grinding discs, means actuated by the second control element for completing a circuit to one or both of said feed actuating control means after said workpiece is clear of the grinding discs.

5. In a disc grinder having annularly opposed grinding discs, means for rotatably supporting said discs, said disc supporting means being slidably mounted on a bed member, each having means for feeding said discs toward and from one another, means for actuating the feeding means for each of said supporting members to compensate for wear on the grinding discs and thereby maintain a fixed space between said discs, means for controlling said feeding means comprising sensing devices directed to the opposite sides of a workpiece near the point where it emerges from the grinding discs, and means to delay the operation of said feeding means by said sensing devices comprising another sensing device positioned to respond to a workpiece after it has passed said first sensing device and emerged completely from the grinding discs comprising parallel contacts adapted to be actuated by said first sensing device, and connections from each of said contacts through a contact actuated by said other contact to complete a circuit through one or both of said first mentioned contacts.

References Cited in the file of this patent UNITED STATES PATENTS

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