US3802128A

US3802128A - Machine for abrading by extruding

Info

Publication number: US3802128A
Application number: US00248750A
Authority: US
Inventors: R Minear; N Nokovich
Original assignee: Extrude Hone LLC
Current assignee: Extrude Hone LLC
Priority date: 1972-01-13
Filing date: 1972-04-28
Publication date: 1974-04-09
Anticipated expiration: 1991-04-09
Also published as: FR2168774A5; IT976832B; SE406049B; CH549440A

Abstract

A machine is provided for abrading a metal workpiece by extruding through or across it a medium in which are dispersed finely divided abrasive particles, the medium being of such a character that under the extrusion pressure it holds the abrasive particles in such contact with the workpiece as to remove metal as desired. The machine provides rugged and substantially inflexible support for the extruding mechanism and the workpiece during operation so that the application of the abrading medium to the workpiece is very closely controlled, so that long production runs at accurately controlled very fine tolerances are possible.

Description

United States Patent [1 1 [111 3,802,128 Minear, Jr. et al; Apr. 9, 1974 MACHINE FOR ABRADING BY 3,583,103 6/1971 Rystrom 5m EXTRUDING 3,039,234 6/1962 Balman 51/2 R t D 3,521,412 7/1970 McCarty 51/317 [75] Inventors: Robert Minear, Jr., lrwm; Nicholas Nokovlch Greensburg' both of 7 Primary Examiner-James L. Jones, Jr. Attorney, Agent, or Firm-Baldwin, Egan, Walling & [73] Assignee: Extrude Hone Corporation, Irwin, Fetzer Pa. 22 Filed: Apr. 28, 1972 [57] ABSTRACT [21] Appl. No.: 248,750

Related us. Application Data 3.634.973 1/1972 McCarty ..51/2R A machine is provided for abrading; a metal workpiece by extruding through or across it a medium in which are dispersed finely divided abrasiveparticles, the medium being of such a character that under the extrusion pressure it holds the abrasive particles in such contact with the workpiece as to remove metal as desired. The machine provides rugged and substantially I inflexible support for' the extruding mechanism and the workpiece during operation so that the application of the abrading medium to the workpiece is very closely controlled, so that long production runs at accurately controlled very fine tolerances are possible.

13 Claims, 24 Drawing Figures SHEET 3 BF 7 "MENTEU APR 9 I974 FFGIO FIGII PATENTEBAPR 9 m4 U u 7 3302.128

TOP MEDIA TOP MEDIA DRIVE OFF CENTER INDICATOR CYLINDER OFF semen mmcaron SAFETY LIMITS 46 SAFETY LIMITS E51 L I I Eil #9? i J97 til-AMP CLAMP MACHINE FOR ABRADING BY EXTRUDING This application is a continuation-in-part of our copending application Ser. No. 217,567, filed .Ian. 13, 1972 now abandoned.

BACKGROUND OF THE INVENTION as is desired. There are many jobs calling for such abrasion by extrusion, especially in very sophisticated technologies, where the amount of metal removed by the process here discussed must be held to extremely fine tolerances over long production runs of identical workpieces. In order tocontrol such fine tolerances using this abrasion by extrusion process, it is necessary not only to have a substantially exact amount of the medium containing the abrasive particles passed through each workpiece with close control of the size and character of the abrasive particles and with close control of the viscosity of the vehicle medium, but, in addition, it is necessary to provide a very rugged and substantially infle'xible'support for the extruding mechanism on up posite sides of the workpiece, and to insure firm clamping of the workpiece between the extruding mechanisms during the extruding operation to insure that no variables occur in such operation of abrasion by extrusion. 7

An object of the present invention then is to provide upper and lower vertically oriented-positive acting driving devices for the abrasive medium, such as pistons and cylinders, these devices axially aligned with the upper device rigidly supported in a massive beam which is snugly held between two parallel, linear, vertically extending guideways at each end of thebeam with guide follower members on the beam engaging the guideways so as'to hold the beam against fluctuation in any horizontal direction; and with the lower medium driving device rigidly held in a massive support in the base of the machine so that vertical or horizontal deviation in either the massive beam or the massive support is substantially eliminated.

Another object of the invention is to provide hydraulic clamping means holding the upper medium driving device tightly against the upper surface of a workpiece which rests upon the lower medium driving device, with means for insuring heavy clamping pressure be fore the abrading by extrusion operation can take place.

Other objects and advantages of this invention will be apparent from the accompanying drawings and specifn cation and the essential features thereof will be set forth in the appended claims.

In the drawings,

FIG. 1 is an elevational view of a preferred embodiment of the machine of this invention with certain portions broken away in section to more clearly show the construction;

FIG. 2 is a top plan view of the same;

FIG. 3 is a top plan view of the massive beam providing the head frame, the same being taken along the line 3-3 of FIG. 1 and showing the construction of the beam itself;

FIG. 4 is a side elevational view of the beam of FIG.

FIG. 5 is asectional view taken along line 5-5 of FIG. 3;

FIG. 6 is a view taken along the line 6-6 of FIG. 2, enlarged, 1 FIG. 7 is a view taken from the upper side of FIG. 6;

. FIG. 8 is a top plan view of the massive support be- I neath the workpiece, this view being taken along the line 88 of FIG. 1 and showing the support itself without other elements;

FIG. 9 is a central sectional view of the same taken along the line 9-9 of FIG. 8;

FIG. 10 is a sectional view taken along line 10-l0 of FIG. 8;

FIG. 11 is a fragmental sectional view, enlarged, taken along the line ll-l1 of FIG. 1;

FIG. 12 is a diagram illustrating the hydraulic controls for the machine;

FIG. 13 is a diagram, explaining the location of certain switches in the control system;

FIG. 14 is a diagram illustrating the electrical controls for the machine; I

FIG. 15 is a fragmental front elevational view of a modification showing the only variation in a modified machine otherwise exactly like FIG. 1;

FIG. 16 is a top plan view of the same similar to FIG. 2 but showing the modification;

FIG. 17 is a side elevational view of a beam like that of FIG. 3 but slightly modified;

FIG. 18 is a fragmental top plan view, enlarged, taken at the left-hand-end of FIG. 16;

FIG. 19 is a front elevational view of the structure shown in FIG. 18;

FIG. 20 is a fragmental top plan view, enlarged, taken at the left-hand end of FIG. 16;

FIG. 21 is a sectional view taken along the line a 2121 of FIG. 20;

FIGS. 22 and 23 are respectively front elevational views of two plate components of a guide shoe shown .in sectional view in FIG. 21; while FIG. 24 is a side elevational view of the plates of FIGS. 22 and 23 when assembled.

Referring to FIG. 1, a generally rectangular base 1 underlies the machine and supports a table work top 2. Spaced at opposite sides of the table top are two vertically extending guides 3 and 3a, the same being of channel form as shown in FIG. 11 each having a web 4 and flanges 4a and 4b at right angles thereto and the two channels opening toward each other. An elongated head frame in the form of a massive beam 5 is supported for vertical reciprocation in the

guides

3 and 30 by guide follower members which are rollers 5a and 5b best seen in FIGS. 1 and 2, there being two of these guide rollers at a lower level at each end and two of the guide followers at an upper level at each end, or a total of eight guide rollers. Referring to FIG. 11, it will be noted that the vertical edge of the flange 40 is cut away to provide a vertically extending flat guide way 6 and the guide follower rollers 5b at each end of the beam 5 are cylindrical and in each case engage the flat way 6. The flange 4b of each of the vertical guides is cut away to provide a V-shapc way 7 and the guide fol lower rollers 5a at each end of the beam 5 have complementary V-shape peripheries to coact with the ways 7. Note that there are follower rollers at both upper and lower levels at each end of the beam and at the lefthand end of the beam in FIGS. 1 and 2, at the front side both of the rollers have V-shape peripheries while at the rear side both rollers at their upper and lower levels are cylindrical. At the right-hand end of beam 5' this situation is just reversed with the cylindrical rollers being in the front at both levels while the V-shape rollers are at the rear at both levels. Thus, the guide follower rollers by their contact with the vertical guides 3 and 3a prevent relative movement between the beam 5 and the vertical guides in two horizontal directions at right angles to each other. The snug engagement between the follower rollers and their coacting ways is assured by the structure shown in FIGS. 2, 6 and 7. A shaft 6a or 7a is provided about which its associated follower rotates and where the shaft or shaft bolt passes through the vertical wall of the beam 5 it is surrounded by an adapter 8 having a square section which is received in a square pocket on the beam 5 and when a nut 9 is pulled up on the threaded end of the bolt 6a or 7a a wedge portion 8a is pulled up tight against a wedge 8b which is rigidly held in the beam 5. Elongated openings 23 through the vertical sidewalls of the beam 5 permit this endwise adjustment of the guide followers. The vertical channel guides 3 and 3a are of heavy steel plate and each of them is welded to a heavy base plate 10 which is firmly secured by a plurality of bolts 10a to a strong rigid underlying structure to be later described.

The beam 5 which forms the elongated head frame is best understood as shown in FIGS. 3, 4 and 5. It is comprised of heavy steel plates rigidly welded together. Vertical parallel side plates 24 are welded to vertical end plates 25 at the corners. Four vertical intermediate braces are shown at 26a, 26b, 26c and 26d. All of the

plates

24, 25, 26a26d extend the full depth of the beam and the braces 26a-26d are welded for-the full depth rigidly to the vertical side plates 24. A hanger structure is provided for the attachment of clamping devices which serve to move the beam 5 upwardly and downwardly. These hangers are identical at opposite ends of the beam and consist of a vertical plate 27 extending the full depth of beam 5 and welded to brace 26b and to both portions of brace 26a which extend on opposite sides of plate 27 and welded thereto. All of these welds extend the full depth of the beam 5. Approximately at mid depth of beam 5 two gusset plates 28 are provided extending horizontally outwardly from the brace 26a and extending from the central hanger plate 27 outwardly to the side plates 24. These parts are all welded together. For attaching the clevis 29 which is associated with the hydraulic clamping jacks, a structure is provided consisting of two donut shape plates 30 welded to opposite sides of hanger plate 27 with their central openings aligned with a similar opening at 27a in plate 27. When the parts are assembled as shown in FIGS. 1 and 2, the clevis 29 lies outside of the members 30 and the pivot pin 31 holds the parts together. At the center of the beam between the plates 26b and 26c there are welded two parallel plates 32 flush with the top and bottom of beam 5, these plates having central This is referred to in the claims as a massive beam." Means is provided beneath the table work top and in vertical registration beneath the elongated head frame 5 to provide a massive support for the lower medium driving device to substantially eliminate all vertical flexing of the lower medium driving device during operation of the machine. This'support is best shown in FIGS. 8, 9 and 10. The two main longitudinally extending members are two heavy structural channels having their webs 80a parallel and back-to-back. Bracing members include a heavy plate 81 at each end welded between the channel flanges 80a and each having a through opening 81a for passage of the piston rods of the clamping jacks. In the center of the support two bracing plates 22, one at the top and the other at the bottom, are welded between the channel webs 80a and they have registering central circular openings 82a through which the lower medium driving device cylinder passes. Parallel vertical bracing plates 83 are welded to the top and bottom plates 82. Otherstrong bracing members 84 are welded between the channel webs 80a at the bottom near each end. In one embodiment of this invention, this support member is 45 inches long, 18 inches wide and 10 inches deep and is referred to in the claims as a massive support.

Upper and lower vertically oriented coaxial positively actuated driving devices for the abrading medium are provided. They must be positively actuated to insure that each cycle of the machine forces a measured amount of the abrading medium through the workpiece in order to obtain the sophisticated results contemplated by this invention. These medium driving devices are here shown as comprising in each case a cylinder and coacting piston for driving the abrading medium with the piston having a piston rod connected with an associated hydraulic jack double-acting to cause vertical reciprocating strokes of the medium driving piston. The upper medium driving cylinder 22 is snugly held in the openings 32a of beam 5 by collar 85 threaded on the cylinder in opposite directions to engage the beam 5 and then pulled up tight'by a spanner wrench gripping pluralholes 86. The piston 21, reciprocable in the cylinder 22, is exactly like the piston 21a shown in the lower medium driving device. This piston is sealed against the inner wall of cylinder 22 the same as the seal 87a shown in the lower medium driving device. Piston rod 18 is threaded into the piston 87 and extends into the cylinder 16 of the hydraulic jack 15 and there connected with piston 17 which is a'double-acting piston reciprocating in cylinder 16. The lower end of cylinder 16 is closed by cylinder head 19 and the upper end by cylinder head 20. It should be understood that where piston rod 18 passes through the cylinder head 19 there is a seal (not shown) to prevent leakage of the hydraulic fluid. Inlet and discharge lines are provided for the hydraulic fluid, line 43 communicating through cylinder head 20 and line 44 communicating through cylinder head 19. A spacing arrangement is shown at 88, and a similar device in the lower medium driving structure at 88 a, which comprises a flange 89 and a collar 90 on one side and a flange 91 on the other side, with four or more cylindrical spacers 92 held firmly between these members by means of a plurality of bolts 92. The lower medium driving device is exactly like that just described and all of the parts are given similar reference numberswith the suffix a.

The lower medium driving cylinder 22a is snugly received in the openings 82a of the massive support and is held firmly there by collars 85a threaded on the cylinder and drawn up tight and then pinned in place or otherwise held. 1

The lower end of media cylinder 22 and the upper end of media cylinder 22a are closed respectively by

caps

94 and 94a screwed in position. These caps have suitable through openings 95 and 95a respectively so that a workpiece 96 clamped between them has the through opening 96' in position to be traversed by the abrading medium as it passes from cylinder 22 to 22a and back again. Preferably, a positioning shoulder 96a is provided on the cap 9411 so as to assist in accurately positioning the workpiece for the abrading operation. Preferably, some means is provided for insuring against leakage of the abrading medium as it passes through the workpiece between openings 95 and 95a. This might be O-rings like those shown at 11 and 42 in the above mentioned McCarty U.S. Pat. No. 3,521,412, or it might consist of sealing rings placed in position before the workpiece is tightly clamped in place.

Means is provided for raising and lowering the upper media cylinder 22 and its associated jack 15. This comprises two hydraulic cylinders 97 assembled on the base in registration beneath opposite ends of the beam 5 and fitted with pistons 97a and piston rods 97b, to the upper ends of which are attached clevises 29 previously described as being connected by the pivot pins 31 with the hangers 27 of the head frame beam 5. it should be noted that the piston rods 97!) pass through aligned into the tank reservoir. An air bleed is shown at 109 so as to remove any pockets of air when first starting up the hydraulic system. The hydraulic fluid under pressure passes through line 110. The: return line for hydraulic fluid is shown at 111 and passes through filter 112 before returning to the reservoir 107. The top media drive cylinder 16 is shown diagrammatically and is driven upwardly by fluid supplied through line 113 and is driven downwardly by fluid supplied through line 114. it will be understood that both

lines

113 and 114 are combined inlet and discharge alternately. The flow openings in the guide column bases 10, the table top 2 and the bracing member 81 of the massive support. These parts are all firmly fastened together by a plurality of bolts 1.0a so that everything is rigidly held in place by the massive support. Thcpistons 97a are operated in opposite directions by hydraulic fluid using combined inlet and discharge conduits 98 at the top of cyl inders 97 and similar conduits 99 at the bottom thereof.

Referring to FIG. 1, limit switches LS5 and LS6 are mounted on the beam 5 in position to have their actuators 100 traveling closely along the guide ways 6 or so as to detect any tilting of the beam 5 out of a true horizontal position as the hydraulic jacks 97 are oper ated in a clamping direction to hold the workpiece 96 between the media cylinders. These two limit switches are normally closed but any tilting of the beam 5 out of the horizontal position will move the actuator 100 of one or the other of the limit switches sufficiently to open the line and to stop the clamping action as will be later described.

Guards are shown broken away at 101 and in section at 102., the latter guards being mounted on vertical structural members 103 rigidly connected to the outer ends of the beam 5.

The controls for operating the above described ma chine will now be explained in connections with FIGS. 12,13 and 14.

In FIG. 12, the hydraulic system is shown with certain connections with the electrical system of FIG. 14 shown so that the operation will hereinafter be clear. A motor M, whose electrical circuit is shown in FIG. 14, is drivingly connected with a pump 104 whose intake is through line 105 and filter 106 from hydraulic fluid in the reservoir 107. Oil from the case drain of the pump passes through an air to oil cooler 108 and back to cylinder 16 is controlled by a four-way valve 115 which is normally urged to neutral position as shown in FIG. 12 but is moved toward the left by energization of solenoid S5 to provide pressure fluid through line 114 which drives piston 17 downwardly, and which is energized for movement toward the right by solenoid S6 which feeds pressure fluid through line 113 to drive piston 17 upwardly. In a similar manner, the bottom media drive cylinder 16a is supplied with hydraulic fluid through

lines

113a and 114a under the control of a four-way valve 1150. This again is a self-centering valve and is driven toward the left upon energization of solenoid S4 which provides pressure fluid through line 114a to drive piston 17a upwardly. When solenoid S3 is energized, it moves the valve 115a toward the right supplying pressure fluid through line 113a to drive piston 17a upwardly. At 127 are shown flow control valves 127 which adjust the flow into the hydraulic cylinder, thus'regulating the stroke speed. Flow in the opposite direction is free. i

The work-clamping cylinders 97 are shown diagrammatically and one will recall that they have piston rods 1 9'7!) which are connected by clevises 29 to the head frame beam 5. It will be noted that the two devices 97 are connected in parallel so that pressure fluid through line 116 will drive both pistons 97a downwardly in a clamping action whereas pressure fluid through line 117 will drive both pistons upwardly to release the clamping action on a workpiece. Four-way valve 118 controls the action of the two clamping jacks. This again is a normally centered valve which is moved.

toward the left upon energization of solenoid S1 to supply pressure fluid through line 116 to provide a clamping action. When solenoid S2 is energized, it moves the four-way valve 118 toward the right so as to supply pressure fluid to line 117 moving the pistons 97a upwardly to release the clamping action.

Pressure switch PS1 is connected with line 1 16 which supplies fluid above pistons 97a to provide clamping action. lln one embodiment of this invention, this switch is preset in the position shown in FIG. 12 to about 400 p.s.i. and is moved to the dot-dash position when the clamping pressure in the cylinders 97 exceeds that value. This pressure can be read upon gauge 119. At 128 are pilot operated check valves to maintain clamp pressure when the clamp is closed.

At 120 is shown an accumulator which in one embodiment of this invention is precharged at 1,000 p.s.i.

In connection with the bottom media drive cylinder 16a, there is shown a pressure switch PS2 which is normally urged to the full line position shown in FIG. 12. Adjustment of this switch is indicated at 121 so that at a predetermined pressure in line 114a, indicating that the piston 21a is pressing the abrading media in cylinder 22a in an upward direction, then a certain timing operation takes place as will be later described.

A pressure gauge is shown at 122 for checking the pressure developed in the hydraulic system as represented by line 1 10. The device at 123 is a gauge isolater switch which is normally in the off position as shown in FIG. 12, but upon operation of push button 124, a gauge reading may be obtained.

Certain limit switches used in the electrical control circuit are shown in FIG. 13. The pressure switch PS1, as described in connection with FIG. 12, is diagrammatically shown here. The pressure switch PS2, described in connection with FIG. 12, is also shown here diagrammatically. The limit switch LS1 is energized at the very bottom of the stroke of piston 17 as will be later described. The limit switch LS2 is energized at the top of the stroke of piston 17a and the limit switch LS4 is energized at the bottom of the stroke of piston 17a. The limit switches LS1, LS2 and LS4 are operated by contacts located inside of their associated cylinders.

Thelimit switches LS5 and LS6 are shown in FIG. I

and are energized, as described there, upon tilting of.

the head frame beam 5 to stop the clamping action when the beam 5 is off center. I

At the top of FIG.- 14 is shown the motor M which was explained in connection with FIG. 12. The arrangement is such that this motor must be running to operate pump 104 before manual or automatic cycles of the machine may be initiated. The motor is energized as shown through lines L1, L2, L3 by operation of push button PBl which energizes relay MS and closes the contacts MS to maintain the circuit. A transformer is shown connected between lines L1 and L2 to energize the motor control circuits about to be described. Overloads OL are normally closed but will be thrown'out, of course, if the load is too heavy. The green light G indicates that the hydraulic unit is working. An emergency stop is shown at push button P82.

The automatic operating cycle will now be described.

The selector switch SS] in line 13 of FIG. 14 is placed in the automatic position. Both Clamp Close" push buttons, PB3 and PB4, are depressed and held, thus energizing the clamp advance solenoid S1. previously mentioned in connection with FIG. 12. At the same time, this energizes the timer TDE which is set for approximately one second to prevent the operation of tied down buttons PB3 or PB4. This timer will time out breaking the circuit to solenoid S] if either of the push buttons are tied down, or are not depressed simultaneously. If the head frame beam 5 should tilt in either direction, so as to open either limit switch LS5 or LS6, this will break the clamping circuit and the warning light R will tell the operator that the clamp is off center. In this condition, neither the automatic nor the manual cycle can be activated and the operator must depress the Manual Clamp Open switch in line 19 of FIG. 14.

Prior to depressing this switch, the automatic-manual switch SS1 in line 13 of FIG. 14 must be moved to the manual switch position. If either of the Clamp Close buttons PB3 or P84 is released prior to full clamp pressure being achieved, then the clamping cylinders will stop. When the predetermined clamp pressure is achieved, then pressure switch PS1 energizes the relay ICR, breaks the clamp circuit through solenoid Sl, closes the supply voltage to the manual and automatic control devices, and the driving clutch of a counter (not shown) is energized as shown at line 28 of FIG. 14.

This is a counter which is operated at each full cycle of pushing the abrading'media from one media cylinder through the workpiece into the other media cylinder, and then back again. The clamp pressure failure light R in line 17 will be on until the predetermined clamp pressure is reached. The dot-dash position of pressurefailure light R in

line

17 and 18 of FIGS. 14 is a test position to test that the warning light is working.

It was mentioned above that when the predetermined clamp pressure is achieved, pressure switch PS1 energizes the relay lCR in line 12. This acts through relay 3CR in line 25 which through the contacts of counter relay energizes the solenoid S4 which advances the bottom media drive piston 17a. At the same time, it energizes the counting coil of the counter shown in line 27. The pressure switch PS2 (line 29) energizes the media timer 'I' when the proper media pressure is reached in the lower end of cylinder 16a when the piston 17a develops an operating pressure against the media in the lowercylinder. When the media timer times out, it energizes the relay 3CR shown in line 31. This action breaks the circuit to the solenoid S4 stopping the bottom media cylinder advance. At the same time, it closes the energizing circuit to solenoid S5 starting the top media cylinder advance downwardly. Limit switch LS2, shown in FIG. 13, energizes relay 3CR is the bottom media cylinder reaches its maximum stroke before the timer T times out. The relay 3CR is sealed in by the limit switch LS1 shown in FIG. 13. When piston 17 in the top media drive cylinder reaches the lower limit of its travel, limit switch LS1 drops out the relay 3CR, thus causing re-advance of the bottom cylinder.

The sequence is then repeated by relay lCR through relay 3CR and the count contacts 125 energizing the solenoid S4 to advance the bottom media cylinder and to energize the counting coil of the counter, including energization of the media timer T by the pressure switch PS2 when the proper media pressure is reached, and finally the media timer timing out, energizing relay '3CR, breaking the circuit to solenoid S4 of the bottom cylinder advance action, making the circuit to solenoid S5 causing top media cylinder advance, etc.

The counter will count out at the forward stroke of the bottom cylinder piston 17a when the relay 3CR is energized, which transfers the circuit from counter contacts 125 to counter contacts 126. At the lowermost portion of the stroke of the top cylinder piston 17, limit switch LS1 breaks the circuit to relay 3CR, making circuit through the counter contacts 126 and normally closed switch LS4 energizing solenoid S3 causing bottom cylinder retraction. At the lowermost point of its stroke of the piston 17a, limit switch LS4 is actuated which breaks the circuit to solenoid S3 and energizes the relay 2CR. The contacts 2CR are closed completing a circuit through the coil of solenoid S2 causing retraction of the clamping cylinder pistons 970. Release of the pressure switch PS1 as the clamp retracts, deenergizes relay ICR and all control circuits. The relay 2CR is held in by the time delay contacts 2CRTD which, when timed out, de-energizes relay 2CR and clamp open solenoid S2.

If clamp pressure fails, then the top and bottom media cylinders stop motion.

The switch indicated at TGS] in line 5 of FIG. 14 is used to by-pass the Left Clamp Closed push button.

The switch marked TGS2 in line 6 is used to by-pass the clamp interlock relay ICR during a manual operation of the cycle. I

If the cycle is to be operated manually, the selector switch SS1 is placed in the manual" position. Then the operator depresses both of the Clamp Close push button, PBS and PB4, and holds them while energizing the clamp advance solenoid S1. The TDE timer is set for approximately one second to prevent tie down of the buttons P83 or P134. This timer will time out breaking the circuit to solenoid Sll if the push buttons are tied down or if they are not depressed simultaneously. Here again, the limit switches LS5 and LS6 break the clamping circuit and lights a warning light if the clamp tilts off center. When the proper clamping pressure is achieved, then pressure switch PS1 energizes the relay lCR breaking the clamping circuit through solenoid S1 and closing the supply voltage to the manual control devices. Control voltage is then made through selector switch SS1 to the manual push buttons for the topmedia cylinder as shown in

lines

34, 35 and 36 of FIG. 14, and. to the manual push buttons for the bottom media cylinder as shown in

lines

24 and 26. These buttons must be held depressed in order to cause complete traverse of the desired cylinder. Release of the buttons stops the motion. Clamp pressure failure will prevent operation of the manual controls and will light a warning light as previously described. To open the clamps,

depress the Clamp Open" push button and hold the button depressed until the desired opening height is reached.

In using the above described machine in a production run for a large number of identical workpieces, a measured amourit of abrading mediais placed in the lower cylinder 22a above the piston 21a. The abrading media is exactly reproducible according to the teachings of the above mentioned McCarty patent and also of the teachings of the copending patentapplication of Lawrence .l. Rhoades, Ser. No. 194,567, filed Nov. 1, I971. The lower media cylinder 22a and its driving jack 15a are held against substantially any flexing by the massive support, the main members of which are the two back to-back channels80. The upper media cylinder 22 and its driving jack 15 are also held against substantially any flexing by the massive beam 5 guided exactly by the rigid guide columns 3 and 3a with no horizontal play possible because of the snugly fitting follower members 5a and 5b. No tilting of beam 5 is allowed because otherwise the limit switches LS5 and LS6 will stop the operation as has been described. There is assurance that the workpiece 96 will be firmly held between the

media cylinders

22 and 22a by the powerful clamping cylinders 97 with assured heavy clamping pressure checked by the pressure switch PS1 as has been described. Thus, large numbers of workpieces may be abraded or honed within extremely fine tolerance limits so that all workpieces are substantially identical as to the amounts of material abraded therefrom. I

To recapitulate, the counter used in one embodiment is one sold by the Eagle Signal Division of Gulf- Western Industries, Inc. of Davenport, Iowa, under the trademark CYCLFLEX, H2170 Series. To start an automatic cycle, the operator sets the desired number of cycles on the counter, and sets the switch in line 13 of FIG. 14 to AUTO. The machine is then clamped,

- pulling in ICR relay, closing the contacts in the vertical wire between

lines

19 and 20. This circuit supplies power through the common line to line 28, which pulls in the counter clutch contacts on line 27 and the contacts 125 on line 25. The bottom cylinder advances until it hits limit switch'LS2 pulling in SCR relay. When 3CR relay is pulled in, contacts on line 25 of 3CR relay de-energize counterclutch counting one cycle. The top cylinder now advances and at the completion of its stroke, it hits limit switch LS1 dropping the 3CR relay. The contacts on line 25 now close, supplying power to advance the bottom cylinder, thus initiating another cycle.

When all of the preset cycles have been counted and the counter is at zero, contacts 125 on line 25 will open and contacts 126 will close on line 23. As the top cylinder is coming down on its last stroke and hits limit switch LS1, it drops out 3CR relay and then goes to line 23 and through limit switch LS4 whose-normally closed contacts will retract the bottom cylinder. As the bottom cylinder retracts, it trips limit switch LS4 to normally open position, pulling 2CR relay which opens the clamp system. ICR relay then drops out which resets the counter to the preset number of cycles.

The machine is now ready for another processing sequ e r In the modification shown in FIGS. 15 through 24, it should be understood that all parts of the machine are exactly like those shown and described in FIG. 1 except a slight change in the channel shape guides 3 and 3a and the coacting

guide follower members

5c, 5d and 5e which perform a function similar to the guide follower rollers 5a and 5b of the machine of FIG. 1. FIG. 17 has a minor modification consisting of threaded openings to recei ve the bolts clearly shown in FIG. 21.

All other parts having the same structure and function as the machine of FIG. 1 are given the same referen e skew r In this modification, the guide follower members are composite sliding

shoes

50, 5d, and 5e, fixed in opposite ends of the massive head frame 5 with the

shoes

5c and 5d slidingly engaging the outer faces of the flanges 4b and 4a, respectively, of each of the

guides

3 and 3', and with the shoes 5e slidingly engaging the outer face Each of the

shoes

5c, 5d and Se is a composite made of two plates shown in FIGS. 22 and 23 and shown in assembled position in FIG. 24. It should be pointed out that these assembled shoes are shown without the plate laminations in FIGS. 16, 20 and'21 to avoid confusion .i itliedrsw nsse Referring to FIGS. 22, 23 and 24, the plate component is steel or the like and the plate component 13] is of a good bearing material such as Nylon or a tetrafluoroethylene polymer such as sold under the trademark Teflon by E.I. DePont DeNemours & Co., or a softer bearing metal such as bronze. The bearing facing plate 131 has evenly spaced countersunk openings 131a such as two at the top, two at the bottom and two in the center which receive bolts 132 which are threaded into threaded openings 1131a in the steel or other rigid plate 130. The two plates as assembled in FIG. 24 are then secured to the parallel side plates 24 of the massive beam 5 by bolts 13;) threaded into openeach end and at thecepter of each plate 13f). These bolts are threaded through openings 133a in plate 24 (FlGflfiYand held in position by suitable nuts 134. I The same shoe is fixed in the end plates 28 of the massive beam in position to engage the outside surface of the web 4' of the guides 3' and 30' at opposite ends of the massive beam 5. It will be noted that all of these shoes, three at each end of the beam 5, are vertically oriented and are of sufficient length to engage between the head frame and the

guides

3 and 30 at spaced vertical levels, in other words, of sufficient vertical extent to hold the head frame 5 steady.

All of the

shoes

5c, 5d and 5e engage the channel guideways along vertically extending paths as shown at 135 in FIGS. 18 and 19. Preferably, these pathways are milled to provide smooth planar faces but this is exaggerated in FIGS. 18 and 19 inasmuch as there is no stipulated depth for these pathways. v

This modification described in connection with FIGS. through 24 operates exactly as described in connection with FIG. 1 and the associated mechanism thereof except that the guide shoes 50 and 5d prevent relative movement of the head frame in one horizontal direction with respect to the guides 3' and 3a, while the shoes 5e prevent relative movement of the head frame in a second horizontal direction at right angles to the first mentioned direction.

The operation of this modified machine is exactly as described in connection with the first form of the invention and it is somewhat more desirable in its operat-' ing effects because, once the unit is lined up with the guide shoes in engagement with the guide channels, it has proven to maintain a very precise alignment and parallelism between the top operating cylinder 22 and the bottom operating cylinder 22a. Also, once this alignment is made, it appears to remain much longer with respect to precision operation of the extruding parts than the cam follower-roller arrangement described in connection with FIG. 1.

What is claimed is:

1. In a machine for abrading by use of an extruding medium; a base including a table work top; an elongated head frame extending across said table top and of a predetermined width and height; means for guiding said frame for vertical movement toward and away from said table top; said guiding means including two vertically extending guides; one near each end of said frame; each of said guides being strong and rigid and including two parallel linear vertically extending guide ways spaced apart approximately equal to said predetermined width; bracing means rigidly connecting said guide ways; plural guide follower members mounted on said head frame in position to snugly engage said guide ways; some of said guide members near each end of said frame being engageable between said head frame and said guide ways at spaced vertical levels; some of said guide members having engagement with said ways preventing relative movement of said head frame in a first horizontal direction relative to said ways; other of said guide members having engagement with said ways preventing relative movement of said head frame in a second horizontal direction relative to said ways at right angles to said first direction; upper and lower vertically oriented positively actuated medium driving devices axially aligned; each of said devices arranged to discharge medium toward and into the other device through a communicating opening in a workpiece clamped between said devices; said upper device being rigidly mounted in in said head frame; said lower device being rigidly mounted in said base; power means drivingly connected with each of said medium driving devices; said power means carried by said base; and clamping means connected at opposite ends of said head frame for moving said head frame to cause travel of said upper medium driving device towards and away from said lower medium driving device to clamp and release a workpiece between them; said last named means being so constructed and arranged as to maintain a workpiece clamped under heavy pressure.

2. A machine as defined in claim 1; including a massive support rigidly secured to said base in vertical 'registration beneath said elongated head frame and contiguous to the lower surface of said table work top; said lower medium driving device being rigidly mounted in said support; said support extending at its opposite ends beneath said guides in their entirety and eliminating substantially all vertical flexing of said lower medium driving device carried thereby.

3. A machine as defined in claim 2; wherein said head is strongly trussed and braced and forms a massive beam between said clamping means connections and eliminating substantially all vertical flexing of said upper medium driving device carried thereby.

4. A machine as defined in claim 1; wherein said clamping means comprises two vertically oriented hydraulically operated cylinder and piston jacks operatively connected one near each end of said head frame.

5. A machine as defined in claim 4; including control circuit means operatively connected with said power means for said medium driving devices to automatically reciprocate said driving devices alternately upward and downward; and means in said control circuit means normally in circuit non-energizing position and responsive to pressure, at a predetermined value, exerted by said clamping means in work-clamping position for causing energization of said control circuit means.

6. A machine as defined in claim 1; including control circuit means operatively connected with said power means for said medium driving devices to automatically reciprocate said driving devices alternately upward and downward; detector means operatively'associated between said head frame and said guides actuated only by vertical tilting of said head frame relative to said guides; said detector means including a normally closed switch in said control circuit means; and said tilting of said head frame being operative to open said switch and to prevent further operation of said machine.

'7. A machine as defined in claim 1; wherein said guide follower members are rollers rotatably mounted on said head frame.

8. A machine as defined in claim 7; wherein each, of said guides is a vertically oriented U-shape channel having a web and two flanges opening inwardly; the edges of said flanges providing said guide ways; and said web providing said bracing means rigidly connecting said guide ways.

9. A machine as defined in claim 8; some of said guide follower rollers having cylindrical peripheries; some of said rollers having peripheries V-shape in radial section; said guide follower rollers having cylindrical. peripheries at both levels at one end of, and at one side of, said head frame; said guide follower rollers having V-shape peripheries at both levels at said one end of, and at the other side of, said head frame; and said guide follower rollers having V-shape peripheries at both levels at the other end of, and at said one side of, said head frame; and said guide follower rollers having cylindrical peripheries at both levels at said other end of, and at said .other side of, said head frame; the edges of said channel flanges engaged by said guide follower rollers being complementary to the periphery of the associated rollers.

10. A machine as defined in claim 1; wherein said guide follower members are sliding shoes.

I 11. A machine as defined in claim wherein each of said guides is a vertically oriented U-shape channel having a web and two flanges opening inwardly, the outer face of said web and said flanges providing said guide ways; and said web providing said bracing means 13. A machine as defined in claim 11; wherein the portions of said faces of said web and of said flanges engaged by said shoes are provided with smooth surfaces.

Claims

2. A machine as defined in claim 1; including a massive support rigidly secured to said base in vertical registration beneath said elongated head frame and contiguous to the lower surface of said table work top; said lower medium driving device being rigidly mounted in said support; said support extending at its opposite ends beneath said guides in their entirety and eliminating substantially all vertical flexing of said lower medium driving device carried thereby.

6. A machine as defined in claim 1; including control circuit means operatively connected with said power means for said medium driving devices to automatically reciprocate said driving devices alternately upward and downward; detector means operatively associated between said head frame and said guides actuated only by vertical tilting of said head frame relative to said guides; said detector means including a normally closed switch in said control circuit means; and said tilting of said head frame being operative to open said switch and to prevent further operation of said machine.

7. A machine as defined in claim 1; wherein said guide follower members are rollers rotatably mounted on said head frame.

8. A machine as defined in claim 7; wherein each of said guides is a vertically oriented U-shape channel having a web and two flanges opening inwardly; the edges of said flanges providing said guide ways; and said web providing said bracing means rigidly connecting said guide ways.

9. A machine as defined in claim 8; some of said guide follower rollers having cylindrical peripheries; some of said rollers having peripheries V-shape in radial section; said guide follower rollers having cylindrical peripheries at both levels at one end of, and at one side of, said head frame; said guide follower rollers having V-shape peripheries at both levels at said one end of, and at the other side of, said head frame; and said guide follower rollers having V-shape peripheries at both levels at the other end of, and at said one side of, said head frame; and said guide follower rollers having cylindrical peripheries at both levels at said other end of, and at said other side of, said head frame; the edges of said channel flanges engaged by said guide follower rollers being complementary to the periphery of the associated rollers.

11. A machine as defined in claim 10; wherein each of said guides is a vertically oRiented U-shape channel having a web and two flanges opening inwardly, the outer face of said web and said flanges providing said guide ways; and said web providing said bracing means rigidly connecting said guide ways.

12. A machine as defined in claim 11; wherein said shoes are rigid plates having facings engaging said web and said flanges; and said facings chosen from the group consisting of tetrafluoroethylene polymer, Nylon and a soft bearing material having a hardness similar to bronze.

13. A machine as defined in claim 11; wherein the portions of said faces of said web and of said flanges engaged by said shoes are provided with smooth surfaces.