US1858296A

US1858296A - Pressure pad

Info

Publication number: US1858296A
Application number: US448931A
Authority: US
Inventors: Ferris Walter
Original assignee: Oilgear Co
Current assignee: Oilgear Co
Priority date: 1930-05-01
Filing date: 1930-05-01
Publication date: 1932-05-17
Anticipated expiration: 1949-05-17

Description

W. FERRIS May 17, 1932.

PRESSURE PAD Filed May 1. 1930 2. Sheets-Sheet 1 W. FERRIS May 17,1932,

PRESSURE PAD Filed ma 1. 1930 2 Sheets-Sheet 2 duo! we Patented May 17, 1932 UNITED STATES.

PATENT OFFICE WALTER FEBRIS, OF MILWAUKEE, WISCONSIN, ASSIGNOR TO OILGEAR COMPANY, OF MILWAUKEE, WISCONSIN, A CORPORATION OF WISCONSIN PRESSURE PAD Application filed May 1, 1930. Serial no. 448,931.

This invention relates to pressure pads for crank operated presses.

The pressure pad to which the invention applies in particular has a pressure rin to hold the blank against the movable die ur ing the draw stroke of the press and to strip the formed article from the stationary die after the same has been drawn to shape, a piston supporting the pressure ring and arranged in a liquid filled cylinder from which the liquid is expelled through restricted orifices as the piston moves inwardly, means to vary the effective orificearea through which liquid is expelled during the instroke of the piston and thereby regulate the hydraulic pressure within the cylinder in accordance with the movement of the piston and thus regulate the pressure applied to the blank.

by the pressure ring, and means to supply liquid to the cylinder at high pressure to force the piston upwardly and strip the formed article from the stationary die after the movable die has moved therefrom. Such a pressure pad is. disclosed in Patent No. 1,696,140, issued December 18, 1928, to Walter Ferris. I

An object of the invention is. to control the expulsion of liquid from the cylinder by a valve which is mechanically operated in synchronism with the ram of the press and has a graduated orifice area through which the liquid is expelled. I

Another object is to provide a valve which can be readily and easily adjusted to vary the effective orifice area.

According to the invention, the expulsion of liquid from the cylinder is controlled by a valve which has a graduated orifice area, and which is connected to the crankshaft of the press and operated thereby to vary the effective orifice area through which liquid may be expelled.

A pressure pad embodying the invention is illustrated in the accompanyingdrawings in which the views are as follows:

Fig. 1 is inpart an elevation and in part a vertical section showing the pressure pad applied to a crank-operated press.

Fig. 2 is an elevation showing the valve operating mechanism.

Fig. 3 is a vertical section on the line 3-3 of Fig. 1.

Fig. 4 is a vertical section on the line 44 I to a chankshaft 5 which is journaled in the, upper ends of the frame 2, and a die 6 which.

is carried by the ram 3 and cooperates with a stationary die 7 arranged upon a bolster 8 carried by the bed 1.

The blank, from which an article is to be formed by the

dies

6 and 7, is held firmly against the upper die 6 during the drawing operation by a pressure ring 9 which encircles the lower die 7 and is supported from a pressure plate 10 by pins 11 which are slidable ghropgh the bolster 8 and the flange of the The function of the pressure pad is to support the pressure plate 10 and resist the downward movement thereof under the infiuence of the ram 3 so as to maintain the required pressure between the pressure ring 9 and the die 6 to grip the blank therebetween, to strip the finished work from the lower die, and to return the pressure ring 9 to its initial position. a

The downward movement of the pressure ring 10 is resisted primarily by pistons 12, which are attached thereto and reciprocable in cylinders 13 arranged within a reservoir 14 and supported by the base 15 thereof, and secondarily by small lifting pistons 16 which are reciprocable in lifting cylinders 17 arranged within the reservoir 14 and shown as being formed integral with the cylinders 13.

The reservoir 14 and the

cylinders

13 and 17 contain a liquid, such as oil, and the reservoir is connected by a pipe 18 to the'sump of a variable displacement pump 19, such as that disclosed in Patent No. 1,578,233, issued March 23, 1926, to Walter Ferris.

The pump 19 is connected by a pipe 20 to a feed channel 21 which is formed in the base 15 and communicates with the bottoms of the liftin cylinders 17 so that liquid under pressure rom the pump 19 acts against the bottoms of the pistons 16 at all times, thus holding the pressure plate 10 against the bottom of the bolster 8 until the pressure ring 9 is depressed by the ram 3 and raising the pistons 16 after the same have been depressed during the working stroke of the press.

The upward movement of the pistons 16 causes the pistons 12 to be raised by the pressure plate 10 and liquid from tlie reservoir 14 to flow past a check valve 22 and into the cylinders 13 through a channel 23 which is formed in the base 15 and communicates with the cylinders 13 through ports 24. Thus, all the cylinders are kept flooded at all times.

' When the

pistons

12 and 16 are forced downwardly by the ram, liquid is expelled from the cylinders 17 into the pipe 20 and discharged therefrom through a relief valve 25 and a discharge pipe 26 into the reservoir 14,

and liquid is expelled from the cylinders 13' through the ports 24 into the channel 23 and is discharged therefrom through a pipe 27 into a valve cylinder 28 which is arranged alongside the press and preferably carried thereby.

The valve cylinder 28 has a port 29 communicating with the pipe 26, a port 30 communicating with the pipe 27 and a port 31 communicating with the pump 19 through a pipe 32 and the pipe 20. The

ports

29, 30 and 31 are controlled by a valve 33 which is arranged in the valve cylinder 28 and reciprocated from the crankshaft 5 in synchronism with the ram 3. 1

The valve 33 is reduced in diameter intermediate its ends to provide a lower part 34 to control the port 31 and an upper part 35 to control the port 29. The upper part 35 is provided around a part ofits periphery with a numberof longitudinally tapered grooves 36 which are largest at the lower ends thereof and terminate upon the periphery of the part 35 to gradually restrict the, flow of liquid through the port 29 as the valve 33 moves downwardly.

The stem 37 of the valve 33 extends through the head 38 of the valve cylinder 28 and is threaded into an adjusting nut 39 which is carried by a slide 40 and adapted to be rotated relatively thereto. The nut 39 and the valve stem 37 may be rotated relatively to each other to adjust the valve 33 axially and time the same with the ram 3 and to com- .pensate for various thicknesses of blanks from which articles are to be formed by thr

dies

6 and 7.

The valve 33 may be rotated, to vary the number of grooves 36 in registry with the port 29, by a lever 41 which is keyed to the valve stem 37 and held against axial movement by the cylinder head 38, the valve stem 37 having an elongated keyway 42 to enable the same to reciprocate through the head of the lever 41. r

The rotary adjustment of the valve 33 increases or diminishes. the number of active orifices through which liquid may be expelled and thus decreases or increases the pressures existing in the cylinders 13 during the instroke of the pistons 12.

- The valve stem 37 may be held against rotation relatively to the nut 39 by a locknut 43, which is threaded thereon to engage the lower end of the nut 39, and the nut 39 may be held against rotation by a set screw 44 "which is threaded into the slide 40 to engage the flange of the nut 39.

The slide 40 is reciprocated vertically by a connecting rod 45 and held against lateral movement by a guide 46 which is'carried by the frame 2. The connecting rod 45 has its lower end pivoted upon a pin 47 carried by the slide 40 and its upper end pivoted upon a crank pin 48 carried by an adjusting disk 49 which is rotatabl supported on a pin 50 carried by the oranlz thereof.

The position of the crank pin 48, relativel to the crank of the crankshaft 5, may be ad justed by rotating the adjusting disk 49 upon the pin 50 and securing the same in place by bolts 51 which extend through slots 52 in the adjusting disk and are threaded into the end of a sleeve 53 fixed upon the shaft 5 and rotatable therewith.

The valve 33 is thus reciprocated in synchronism with the ram 3, and'the position of the crank pin 48 is preferably so adjusted that the valve 33 reaches the limit of. its downward movement directly after the ram 3 completes its working stroke.

When the crankshaft 5 has moved the upper die 6 into engagement with a blank upon the lower die 7, the blank is gripped firmly between the upper die 6 and the pressure ring 9, and the valve 33 has been moved downwardly until the lower part thereof has uncovered the port 30 and the upper part 35 thereof is in registry with the port 29.

Downward movement of the pressure ring 9 is resisted by the liquid in the cylinders 12 which will be expelled through the ports 24, channel 23, pipe 27, port 30, valve cylinder 28, and the tapered grooves 36 into the pipe 26 through which it is discharged into the reservoir 14. The restricted area of the grooves 36 provides sufiicient resistance to the expulsion of the liquid to cause the downward movement of the pressure ring 9 to create almost any desired pressure within the cylinders 12.

As the press is operated by a crank, the velocity of the ram 3 gradually diminishes as it approaches the end of its working stroke and the grooves 36 are preferably shaped to progressively diminish the effective area shaft '5 upon the axis through which liquid may be expelled and maintain a predetermined pressure or a graduated range of pressures between the pressure ring 9 and the upper die 6 during the instroke of the pistons 12.

,Just before the ram 3 reaches the limit of its stroke, the grooves 36 pass out of registry with the port 29 which is then completely closed by the upper part 35 of the valve 33 and the liquid is expelled through a high pressure relief valve 54 which is connected between the pipe 27 and the discharge pipe 26 and adjusted to create the desired pressure upon the margin of the blank.

As the ram 3 starts to move upwardly, the valve 33 is approaching the limit of its downward stroke and the lower part 34 thereof uncovers the port 31. Liquid is then delivered at high pressure by the pump 19 to the cylinders 13 to create a high pressure therein which is capable of loosening the formed article from the lower die 7.

The pump 19 will also deliver liquid at highpressure to the lifting cylinders 17 and, as soon as the formed article is loosened from the die 7, will cause the lifting pistons 16 to raise the pressure plate 10 until it strikes the bottom of the bolster 8. After the ram 3 has moved upwardly a predetermined distance, the lower part 34 of valve 33 closes the port 31 and the full output of the pump 19 is delivered to the lifting cylinders 17 and accelerates the upward movement of the lifting pistons 16.

The pistons 12 are carried upwardly by thepressure plate 10 which causes the check valve 22 to open and liquid from the reservoir 14 to fill the cylinders 13 and put the pressure pad in condition for a second operation.

The invention herein set forth is susceptible of various modifications without departing from the scope thereof as hereafter claimed.

The invention is hereby claimed as follows: 1 J

1. The combination, with a press having a ram operated by a crankshaft, of a hydraulic pressure pad comprising a pressure member, hydraulic means for sustaining said member including a piston and a cylinder, a plunger valve for controlling the expulsion of liquid from said cylinder and having a number of restricted orifices through which said liquid is expelled, means for adjusting said valve to vary the effective total area of said orifices and mechanical means for operating said valve in synchronism with said ram.

2. The combination, with a press having a ram operated by a crankshaft, of a hydraulic pressure pad comprising a pressure member, hydraulic means for sustaining said member including a piston and a cylinder, a plunger valve for controlling the expulsion of liquid from said cylinder and having a number of restricted orifices through which said liquid is expelled, means for adjusting said valve to vary the efi'ective total area of said orifices and means connecting said valve to said crankshaft for operating the same in syn- I chronism with said ram.

3. The combination, with a press having a ram operated by a crankshaft, of a hydraulic pressure pad comprising a pressure member, hydraulic means for sustaining said member including a piston and a cylinder, a valve for controlling the expulsion of liquid from said cylinder and having restricted orifices through which said liquid is expelled, mechanical means for operating said valve in synchronism with said ram, and means for adjusting said valve to vary the number of orifices through which said liquid can be expelled.

4. The combination, with a press having a ram operated by a crankshaft, of a hydraulic pressure pad comprising a pressure member, hydraulic means for sustaining said member including a piston and a cylinder having an outlet, a valve cylinder connected to said outlet, a valve reciprocable in said valve cylinder for resisting and controlling the expulsion of liquid through said outlet during the working stroke of said ram and for directing high pressure liquid into said to said outlet, and a valve reciprocable in said valve cylinder for resisting and controlling the expulsion of liquid through said outlet during the working stroke of said ram and for directing high pressure liquid into said sustaining cylinder after said ram com- .pletes its working stroke and mechanically connected to said crankshaft to be operated thereby in synchronism with said ram.

6. The combination, with a press having a ram operated by a crankshaft, ofa hydraulic pressure pad comprising a pressure member, hydraulic means for sustaining said member including a piston and a cylinder having an outlet, a valve cylinder connected to said outlet, a valve reciprocable in said valve cylinder for controlling the expulsion of liquid through said outlet and having tapered grooves in its periphery through which said liquid is expelled, and mechanical means for operating said valve in synchronism with said ram to vary the effective cross-sectional area of said grooves.

7. The combination, with a press having a ram operated by a crankshaft, of a hydraulic pressure pad comprising a pressure member,

hydraulic means for sustaining said member 5 through said outlet and having tapered grooves in its periphery through which said liquid is expelled, and means connecting said valve to said crankshaft for operating the same in synchronism with said ram to vary the eifective cross-sectional area of said grooves.

8. The combination, with a press having a inder for controlling the expulsion of liquid through said outletv and having tapered grooves in its periphery through which said" liquid is expelled, a guide carried by the frame of said press, a slide arranged upon said guide and adjustably connected to the stem of said valve, a crank pin carried by said crankshaft,and a connecting rod connecting said crank pin to said slide to reciprocate the same and operate said valve in synchronism with said ram.

, WALTER FER-BIS.

ram operated by a crankshaft, of a hydraulic pressure pad comprising a pressure member, hydraulic means for sustaining said member including a piston and a cylinder having an outlet, a valve cylinder connected to said outlet, a valve reciprocable in said valve cylinder for controlling the ex ulsion of liquid through said outlet and having tapered grooves in its periphery through which said liquid is expelled, mechanical means for operating said valve in synchronism with said crankshaft to vary the effective crosssectional area of said grooves, and means for varying the number of grooves through which said Hquid may be expelled.

9. The combination, with a press having a ram operated by a crankshaft, of a hydraulic pressure pad comprising a pressure member,

hydraulic means for sustaining said member including a piston and a cylinder having an outlet, a valve cylinder connected to said outlet, a valve reciprocable in said valve cylinder for controlling the expulsion of liquid through said outlet and having tapered grooves in its periphery through which said liquid is expelled, means connecting said 7 valve to said crankshaft for operating the same in synchronism with said ram to vary the effective cross-sectional area of said grooves, and means to adjust said valve axially.

10. The combination, with a press having a ram operated by a crankshaft, of a hydraulic pressure pad comprising a pressure member, hydraulic means for sustaining said member including a piston and a cylinder having an outlet, a valve cylinder connected to said outlet, a valve reciprocable in said valve cylinder for controlling the expulsion of liquid through said outlet and having tapered grooves in its periphery through which said liquid is expelled, a crank pin carried by said crankshaft and connected to said valve for operating the same, and means for adjusting the position of said crank pin relatively to the crank of said crankshaft.

11. The combination, with a press having a ram operated by a crankshaft, of a hydraulic pressure pad comprising a pressure member, hydraulic means for sustaining said member including a piston" and a cylinder having an outlet, a valve cylinder connected to said outlet, a valve reciprocable in said valve cyl-