US2570592A - Automatic feed mechanisms - Google Patents

Description

Oct. 9, 1951 R. E. PRICE 2,570,592

- AUTOMATIC FEED MECHANISMS Filed Jan. '7, 1949 2 Sheets-Sheet l RALPH PRICE (lttorneu PRICE AUTO TIC lled Jan r 49 F] I I00 0 RA PH CE Patented Oct. 9, 1951 AUTOMATIC FEED MECHANISMS Ralph E. Price, HighfieluLMd; assignor to Landis Tool 00., Waynesboro, Pa.

Application January 7, 1949, Serial No. 69,711

- Claims.

larly to feed mechanisms operable automatically in definite relation to the Work traverse movement of the machine.

The machine for which this invention is intended has a feed mechanism consisting of a feedscrewmoved axially by power for a rapid .feed movement as well as power operated means for rotating a feedscrew fora slow'fed movement. In order to effect automatic adjustment of the feedscrew at each end of the traverse movement, the power means, in this case a piston and cylinder operable through a rack and pinion, must be moved a slight but measured distance. It is also desirable that this movement be adjustable. We prefer to accomplish this by providing a fixed maximum volume of fluid for actuating the feed piston and throttling this supplyin order to adjust the increment of feed. It is, therefore, an object of this invention to provide a shuttle valve operable in timed relation with the reversing mechanism of a'grinding machine for causing incremental movement of a feed mechanism.

It is a further object to provide means for modifying the function of said shuttle valve by means of a selector valve which may be positioned to provide incremental feed at feith'er' 'or both ends of the traverse movement or to substitute a continuous feed movement in the absence of a traverse movement when said'shuttle valve is rendered inoperative.

Figure 1 is a hydraulic diagram of the relative arrangement of parts necessary to carry out the object of the invention.

Figure 2 is a section through the selector valve showing the means for locating the valve in various positions.

Figure 3 is a longitudinal sectional of the selector valve.

Figure *4 is a series-of sections taken through the selector valve in various angularpositions thereof. l

While this invention relates to grinding-ma} chines, it is not limited to such apparatus but may be applied to any machines having comparable functions. Since the invention deals primarily with hydraulic apparatus, it is not considered necessary to include in the drawings details of machine structure. The drawings, thereelevation fore, have been limited to the apparatus essential to the operation of the invention.

The means for producing a traverse movement consists of a cylinder I0 in which a piston II is slidably mounted with a double piston rod I2 ex tending from each end of said cylinder. Fluid under pressure is directed from a pump [5 through line it, throttle valve I1 and line l8 to reversing valve I9 from which it is directed automatically to opposite ends of cylinder l0 through lines 20 and 2|.

Said reversing valve may be shifted by fluid under pressure directed automatically to opposite ends thereof by pilot valve 25 which receives fluid under pressure from line I8 through line 26. Said pilot valve is shown as being actuated by means of a lever 27. Said fiuid is directed auto.- matically through lines and 3] to opposite ends of valve I9. At the same time said fluid is directed automatically through lines and 36 to opposite ends of an automatic feed valve 40. Valve receives fluid under pressure from pump I5 through line I6, line 45, choke coil 46 and line 47. The purpose of said choke coil'is to limit the flow of fluid to shuttle valve 53 and thus prevent too rapid operation thereof. Pressure in line 46 exceeds that in line I8 by the drop across throttle valve I1. Said fluid is directed alternately through lines 50 and 5| to opposite ends of cylinder 52 in which is slidably mounted a piston type shuttle valve 53. Auto feed valve 40 also directs fluid alternately from opposite ends of said shuttle valvethrough lines and BI to a selector valve 10, which will be described later. The pressure of the fluid supplied to cylinder I0 is determined by a fluid operated relief valve 15 of the type disclosed in Patent 2,456,431, granted December 14, 1948.

The portion of the feed mechanism with which ,we are concerned consists of a feedscrew hav ing gear teeth thereon engaging rack teeth 82 on piston rod 83. .Said piston rod is attached to a piston 84 slidably mounted in cylinder 85. Further details of this feed mechanism may be found in Price Patent 2,313,479, issued March 9, 1943. Fluid under pressure for actuating said piston may be supplied from pump I5 through line I8 and line to selector valve IE! and .then through line 9| from saidselector valve to the right-hand end of cylinder 85. Fluid may also be supplied to said selector valve from shuttle valve 53, as described above. 1

The selector valve consists of a housing H30 and a rotatable valve member Ill having a knob I92. Said valve member is hollow and has a throttle valve M5 in one end, which is adjustable by means of a knob 106. At the other end is a relief valve consisting of a ball H0 urged by spring III into closing engagement of said valve member. Said valve is held against axial movement by a screw II5 engaging an annular slot I H3 in the valve member. Said valve may be adjusted angularly to four different positions determined by four peripherally spaced slots or notches I into which a ball I2I is pressed by spring 22 to position said valve member. Said valve member is divided into four sections:

Section AA has an annular groove I connected to the hollow portion of the valve member by a radial passage I26. Section BB consists of two circumferential slots I and I3I on the valve member substantially at right angles to one another. Section CC consists of a passage I diametrically through the valve member and a second passage I36 radially of said valve member and at an angle to passage I35. Said section also has a circumferential slot I3I. similar to section AA in that it consists of a circumferential groove I40 connected to the hollow portion of the valve member by radial passage I II.

Operation The operation of the traverse and reversing mechanism described herein is well known and need not be repeated here.

The operation of the feed mechanism is dependent upon the operation of the reversing mechanism modified by the setting of selector valve I0.

Regardless of the setting of valve I0, automatic feed Valve 40 and shuttle valve 53 are actuated each time the reversing mechanism functions.

Section DD is Automatic feed valve 40 performs a double function: It directs fluid under pressure from high pressure line 47 automatically through lines 50 and 5I to opposite ends of shuttle valve 53. While valve 40 is directing the fluid under pressure from line 4'I to one end or the other of valve 53, it is also directing the fluid discharged from the opposite end of said shuttle valve through lines 60 or BI to selector valve I0. Whether the fluid thus directed to said selector valve is utilized to efiect incremental movement of slow feed piston 84 is dependent upon the setting of said valve I0.

Valve I05 detetrmines the magnitude of said increment. Said valve may be adjusted to permit the passage of any or all of the measured amount of fluid discharged by shuttle valve 53. When valve I05 is so adjusted that only a portion of this fluid is used to effect the feed movement, the unused fluid escapes through relief valve H0 and radial passage I26 in section AA of valve I0 from which it is discharged through line 90 into the low pressure line I8. Thus, the pressure at which fluid is supplied to said cylinder 85 from line 9| is the resultant of the pressure of spring I II and the machine pressure in line I8.

Valve I0 may be set in any one of four angular positions. In the first of these, when the carriage drive piston II is reversed at the left-hand end of its movement, automatic feed valve 40 is in its right-hand position, and the discharge from the right-hand end of shuttle valve 53 passes through line 5|, valve 40 and line 6| to radial passage I36 and section CC of valve 70. From passage I36, said fluid is conducted through throttle valve I05 and radial passage MI in section DD of said valve to line 9| leading to the head end of feed cylinder 85.

When the movement of piston I I is reversed at the right-hand end of its travel, valve 40 is in its left-hand position as shown in Figure 1. In this position the measured amount of fluid discharged from the left-hand end of valve 53 through line 50, valve 40 and line 60 enters a circumferential slot I31 in section CC. Slot I31 in section CC is connected by a port I50 to a similar slot I30 in section BB. In the first position of valve I0, slot I30 is connected with an exhaust passage I53; and thus when piston I I is reversedat the righthand end of its travel, the measured amount of fluid discharged from shuttle valve 53 is exhausted and no feed impulse is given to the feed piston 84.

In the Number 2 position of valve I0, passage I35 in section CC is in line with both of the lines 60 and 6|; and thus the measured quantity of fluid discharged from either end of shuttle valve 53 is directed through throttle valve I05, as described above, to the head end of said cylinder 85.

It might be well at this point to call attention to the fact that sections AA and DD of valve I0 function in the same manner regardless of the angular position of said valve.

In the Number 3 position of valve 10 neither of the lines 60 nor 6| is connected to supply fluid to the center passage of said valve. However, fluid from the machine pressure line enters port I60 of section AA and BB through slot'I3I in section BB to port I6I in section BB. Port IIiI is connected with the center portion of the valve through passage I35, and thus a continuous supply of fluid may be directed through throttle valve I05 and line 9| to complete a continuous or plunge cut feeding movement of piston 84.

In the Number 4 position of valve III, the measured quantity of fluid from the left end of shuttle valve 53 passes through line 50, valve 40 and line 66 to radial passage I36 in section CC of valve I0. From passage I36 said fluid is directed through throttle valve I05 and line 9I to the head end of said cylinder 85. This occurs when piston II is reversed at the right-hand end of its travel. When reversal occurs at the left-hand end of the piston movement, the measured amount of fluid from the right-hand end of valve 53 passes through line 5|, valve 40 and line 6|. Line BI is connected to the center portion of valve I0. It is connected to slot I31 in section CC. In this position of the valve, slot I3! is connected through port IIiI to slot I30 in section BB. Slot I30 in the number four position of valve I6 connects port I6I with exhaust passage I53. Thus, actuation of the feed mechanism occurs only at th right-hand reversal.

I claim:

1. In a grinding machine having a work sup port and a grinding wheel support, means for effecting relative transverse and longitudinal movement between said supports, said transverse moving means comprising a feedscrew and nut, a hydraulic motor for rotating one of said members, a reversing mechanism for said longitudinal moving means, an automatic feedvalve actuated by said reversing mechanism, a shuttle valve of fixed capacity in excess of maximum requirements actuated by said automatic feed valve for supplying a measured maximum quantity of fluid under pressure to said feedscrew operating motor at each reversal of said longitudinal moving means and a selector valve between said shuttle valve and said screw operating motor for preventing operation thereof at one or both ends of the movement of said longitudinal moving means, said selector valve having means for predetermining whether all or a portion of said measured quantity of fluid reaches said feedscrew operating motor, and a relief valve for 3 lay-passing the unused portion of said measured quantity of fluid.

2. In a grinding machine having a work support and a grinding wheel support, means for effecting relative transverse and longitudinal movement between said supports,said transverse moving means comprising a feedscrew and nut, a hydraulic motor for rotating one of said members, a reversing mechanism for said longitudinal moving means, an automatic feed valve actuated by said reversing mechanism, a shuttle valve of fixed capacity in excess of maximum requirements actuated by said automatic feed valve for supplying a measured maximum quantity of fluid under pressure to said feedscrew operating motor at each reversal of the movement of said longitudinal moving means, a selector valve between said shuttle valve and said screw operating motor for preventing operation thereof at one or both ends'of said longitudinal movement, and a restriction in the supply of fluid to said shuttle valve to limit the rate of movement thereof.

3. In a grinding machine having a work support and a grinding wheel support, means for effecting relative transverse and longitudinal movement between said supports, said transverse moving means comprising a feedscrew and nut, a hydraulic motor for rotating" one of said members, a reversing mechanism for said longitudinal moving means, an automatic feed valve actuated by said reversing mechanism, a shuttle valve of fixed capacity in excess of maximum requirements actuated by said automatic feed valve for supplying a measured maximum quantity of fluid under pressure to said feedscrew operating motor at each reversal of said longitudinal moving means and a selector valve between said shuttle valve and said screw operating motor for preventing operation thereof at one or both ends of the movement of said longitudinal moving means, said selector valve having means for predetermining whether all or a portion of'said measured quantity of fluid reaches said feedscrew operating motor, and a throttle valve in said selector valve for determining how much of the output of said shuttle valve is supplied to said feedscrew operating motor.

4. In a grinding machine having a work support and a grinding wheel support, means for effecting relative transverse and longitudinal movement between said supports, said transverse moving means comprising a feedscrew and nut,

a hydraulic motor for rotating one of said mec h anisms, a reversing mechanism for said longitudinal moving means, an automatic feed valve actuated by said reversing mechanism, a shuttle valve of fixed capacity in excess of maximum requirements actuated by said automatic feed valve for supplying a measured maximum quan-' tity of fluid under pressure to said feedscrew operating motor at each reversal of said longitu dinal moving means, means including an adjus= table restriction for directing a predetermined portion of the output of said shuttle valve to said feedscrew operating motor, and a selector valve between said shuttle valve and said screw operating motor for preventing operation thereof at one or both ends of the movement of said longitudinal moving means.

5. In a grinding machine having a work support and a grinding Wheel support means for effecting relative transverse and longitudinal movement between said supports, said transverse moving means comprising a feedscrew and nut, a hydraulic motor for rotating one of said members, a reversing mechanism for said longitudinal moving means, an automatic feed valve actuated by said reversing, mechanism, a shuttle valve of fixed capacity in excess of maximum requirements actuated by said automatic feed valve for supplying a measured maximum quantity of fluid under pressure to said feedscrew operating motor at each reversal of said longitudinal moving means and a selector valve between said shuttle valve and said screw operating motor for preventing operation thereof at one or both ends of the movement of said longitudinal moving means, said selector valve having means for predetermining whether all or a portion of said measured quantity of fluid reaches said feedscrew operating motor, and means for by-passing the fluid not used for said motor.

RALPH E PRICE.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 2,022,542 Flygare et al Nov. 26, 1935 2,127,877 Maglott Aug. 23, 1938 2,335,356 Price et a1 Nov. 30, 1943

Images