US2747714A - Air-operated clutch-brake mechanism - Google Patents

Description

May 29, 1956 c. M. EASON AIR-OPERATED CLUTCH-BRAKE MECHANISM 5 Sheets-Sheet 1 Filed March 19, 1952 INVENTOR. CZQfS/ZCMEQSOIZ, BY

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May 29, 1956 v c. M. EASON AIR-OPERATED CLUTCH-BRAKE MECHANISM 5 Sheets-Sheet 2 Filed March 19, 1952 1 N V EN TOR. dare/we Miczaorz, BY flaw,

May 29, 1956 c. M. EASON AIR-OPERATED CLUTCH-BRAKE MECHANISM 5 Sheets-Sheet 3 Filed March 19, 1952 IN V EN TOR.

May 29, 1956 c. M. EASON AIR-OPERATED CLUTCH-BRAKE MECHANISM 5 Sheets-Sheet 5 Filed March 19, 1952 INVENTOR. 6%"ezzcemfwofz, BY M, ddddn United States Patent AIR-OPERATED CLUTCH-BRAKE MECHANISM Clarence M. Eason, Waukesha, Wis., assignor to Industrial Clutch Corporation, Waukesha, Wis., a corporation of Wisconsin Application March 19, 1952, Serial No. 277,509

9 Claims. (Cl. 192-144) The present invention relates to an improved airoperated clutch-brake mechanism. My improved mechanism has been devised particularly for punch presses, dieing machines and the like, but its use is not limited thereto.

The invention has particular application to dieing machines, punch presses and the like of the high speed type, adapted for single stroke operation or continuous running operation selectively at the will of the operator. in many of these machines, using friction clutches, operating speeds in the neighborhood of 500 to 600 R. P. M. are quite prevalent, and some of these machines have attained operating speeds as high as 800 to 1000 R. P. M. There is a continuous trend of development toward the higher operating speeds, for obtaining greater production of the machine, but these higher speeds have greatly complicated the provision of satisfactory controls for selectively obtaining either single stroke operation or continuously running operation, and also for obtaining a very slow inching movement of the ram head when changing or adjusting dies, or performing other preliminary operations. This slow inching movement of the crank and ram requires a very critical and reliable control of the clutch and brake operation, particularly in view of the high speed of several hundred revolutions per minute.

The general object of the present invention is to provide an improved construction and arrangement of control mechanism for obtaining the selective single stroke operation or continuous running operation, and also obtaining the extremely slow inching movement of the ram at desired times, all of which controls are performed with the driving fly wheel continuing to operate at the same constant speed of several hundred revolutions per minute. At these operating speeds, it is physically impossible to admit full compressed air pressures to the brake and clutch mechanisms and then release these pressures with sufficient quickness and certainty to obtain a slow reliable inching movement of the crank and ram. In my improved control mechanism I transmit a reduced, closely regulated pressure to the brake and clutch mechanisms during such inching movement, which reduced closely regulated pressure is under the instant control of the operator at all times.

Another object of the invention is to provide an improved construction and arrangement of control mechanism which will have an inherently timed relation between brake operation and clutch operation so as to avoid any objectionable overlapping engagement of the clutch and brake, with consequent overheating of the clutch.

Another object of the invention is to provide an improved transfer valve arrangement in the combination for automatically effecting a transfer of compressed air.

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proved construction of air-operated clutch, and an improved construction of quick release valve in association therewith for use in the present control arrangement.

Other objects, features and advantages of the invention will appear from the following detailed description of one preferred embodiment of the invention. In the accompanying drawings illustrating such embodiment:

Figure l is a fragmentary side elevational view of a dieing machine embodying my invention, showing the relation of the clutch, brake and the several controls with respect to the operating parts of this dieing machine;

Figure 2 is an end elevational view of the latter, as viewed from the left hand end of Figure 1;

Figure 3 is an axial sectional view of the improved air-operated clutch used in this mechanism;

Figure 4 is a fragmentary transverse sectional view through the brake mechanism which I prefer to employ in the present apparatus;

Figure 5 is a fragmentary sectional view taken approximately on the plane of the line 55 of Figure 4;

Figure 6 is a longitudinal sectional view through the transfer valve, taken approximately on the plane of the line 6-6 of Figure 4;

Figure 7 is a detail sectional view on a much larger scale, showing the mounting of the O-rings in this transfer valve;

Figure 8 is a front view, partly in elevation and partly in section, showing the automatic timer mechanism;

Figure 9 is a fragmentary detail View showing part of the selecting mechanism for selecting between single stroke operation and continuously repeating operation; and

Figure 10 is an axial sectional view through the modulating valve for obtaining the slow manually controlled downward movement of the press ram.

In Figures 1 and 2 I have shown a more or less conventional dieing machine, designated 20 in its entirety, comprising the usual base 21 from which rises the pedestal portion 22. The crank shaft 24 is journaled in side bearings mounted between the pedestal portion 22 and the upper frame portion 25. in these dieing machines, the ram carrying the movable die section is disposed above the crank shaft 24 and frame portion 25, such ram being indicated at 26, and being connected to the crank shaft through pull-down rods 27 passing down through the upper frame portion 25, as is well understood by those skilled in the art. Located at one end of the machine to operate on one end of the crank shaft are the airoperated clutch mechanism designated 31 in its entirety, and the air-operated brake mechanism designated 32 in its entirety. Located at the other end of the machine and operatively connected with the other end of the crank shaft 24 is the automatic timer mechanism indicated at 33 in its entirety, this timer mechanism comprising the automatic control and the manual control for selectively obtaining either single stroke operation or continuous running operation. The modulating or inching valve for obtaining the very slow, critically controlled downward movement of the ram 26 is indicated in its entirety at 34, this inching valve being preferably located adjacent to the automatic timer mechanism 33 for convenience of operation. The dieing machine or press is adapted to be driven from any suitable source of power, typically represented by the electric motor 38 transmit ting a drive through a plurality of parallel -belts 39 to a grooved fly wheel 40 which is rotatably mounted upon the right hand end of the crank shaft between the clutch mechanism 31 and the brake mechanism 32.

Referring now to Figure 3, this fly wheel 40 is mounted on anti-friction bearings 42 carried by the crank shaft 24, and secured to the outer side of said fly wheel by cap screws 44 is the driving element 45 of the clutch mech anism 31. The driving clutch element 45 comprises a bolting ring 46 having angularly spaced lugs or bosses 46' through which pass the mounting cap screws 44. The circumferential slots 46" between bosses 46 form 'a'i'r circulating openings for cooling the clutch. Formed integral with the bolting ring 46 and projecting laterally therefrom is 'a drum-shaped portion 47 having angularly spaced cooling apertures 48 therein. Projecting radially inwardly from said flange and hub portion is a plate or disc portion 49 which functions as one of the frictional driving elements of the clutch 31.

Bolted to the outer end of the drum portion 47 by cap screws 51 is a cylinder head 52 in which is reciprocably mounted an air-operated piston 53. The cap screws 51 screw into the ends of spacing :posts or rods 54 which pass from the inner flange portion 49 out to the cylinder head 52, and which function as angularly spaced cylindrical guides for guiding the sliding movement of the shiftable driving clutch elements. A tight sliding seal is maintained between the piston 53 and the cylindrical wall portion of the cylinder head 52 by a well known form of O-ring 56 composed "of neoprene or other like material. This O-ring is protected from dust, dirt, etc. by a suitable dust stop ring '57.

The force of the piston is transmitted through an annular ring or boss portion 58 projecting rearwardly from the inner side of the piston 53, for abutment against a pressure transmitting-ring 59 which is joined by spider arms 61 to an axially shiftable driving clutch plate or disc 62. The spaces 61' between spider arms 61 provide for the circulation of air to cool the clutch and piston. The rim portion of this driving clutch plate 62 has a plurality of angularly spaced apertures 63 therein which have sliding guided engagement on the spacer posts 54. Interposed between the non-shifting driving clutch plate 49 and the power shifted driving clutch plate 62 is a floating driving clutch plate 65 which, for convenience of manufacture is preferably made up of left and right hand sections 65a and 65b provided with air impelling passageways 66 therebetween, the two sections having abutting :portions 67 atspac'edintervalswith respect to the air'impellin'g passageways 66. The outer rim portions of the sections 6511 and 65b "are provided with guide apertures 69 which'havesliding guided engagement on the spacing guide posts 54, This "floating clutch plate 65 presents radially extending friction clutch surfaces on {opposite sides'thereof for coactingwith the'driven clutch discs.

W There are two of these drivenclutch-discs,designated 71 and 72 respectively, the drivendisc 71 being interposed between the non-shifting driving clutch plate 49 and the floating driving clutch-plate 65, and the other driven disc 72 being interposed between the power shifted driving'clutch'plate 62 and the floating driving clutch'plate 65. These driven clutch discs 71 and 72each comprise segment-shaped outer plate portions 73, to the opposite sides of which friction facings 74 of corresponding segmental shape are-secured by rivets 75. Extending inwardly from the segment-shaped plateportions are spring fingers or arms 77 having apertured inner ends 78 for receiving mounting bolts 79. These bolts '79 secure the apertured inner ends 78 of the-spring arms to bolting flanges 81 projecting outwardly from separate hub structures These two hub structures 82, 82 have independently slidable mounting upon a common mounting hub 8 3, being rotatively joined thereto by'coacting driving splines or key ways and keys-84. The central driven hub '83 is secured to a tapered end24' of the crank shaft 24 by a suitable driving key 86 and locking nut 87. The lateral flexibility inherent in the spring fingers 77, and the lateral shiftability afforded by the splined mountings 84, enable the driven clutch discs 71 and 72 to center themselves properly in both the clutch engaged and clutch disengaged positions of th'e'parts, and particularly to avoid frictional dragging contact between the driving 4 and driven clutch surfaces when the clutch is in its disengaged position.

The clutch is spring released through the medium of a plurality of spring assemblies, each comprising a spring guide rod 91 passing freely through the outer portion of the floating clutch plate 65, and carrying compression springs 92 and 93 upon its opposite ends, inwardly and outwardly of the floating clutch plate 65. These spring assemblies 91, 92 and 93 occur at angularly spaced points around the clutch assembly, preferably o'ccuring in alternating relation with respect to the guide posts 54. The inner or adjacent ends of the two springs 92 and 93 of each spring assembly abut against washers 94 mounted in recessed pockets 95 formed in the outer faces of the clutch plate sections 65a and 65b. The outer ends of these springs bear against washers 96 which have free sliding movement on the rod 91, but are limited in their outward movements along said rod by snap rings '97 on the ends of the rods. The washers 96 at the left hand *or inner end of each spring assembly abut against the bottoms of shouldered po'ck'ets '98 in the driving clutch element 45, and the washers 96 at the opposite end of the spring assembly =have thrusting abutment against the bottoms of shouldered p'ockets 99 formed in the power shifted'drivi'ng clutch plate '62. Hence, the action of the two springs 92 and 93 is to exert a constant separating pressure between the driving clutch plates 49 and 62, and also to exert a centering action on the floating clutch plate 65. Thus, when the clutch is released, these spring assemblies tend to center 'the floating clutch plate 65 and thereby prevent or minimize dragging contact between driving and driven'clutch surfaces in the released condition'of the clutch.

The effective cooling of-'aclutch of this friction type, operating in a heavy duty situation such as a punch press or dieinginachineyis a very important factor in the successful operation'of the mechanism. The continuously rotating driving clutch'element 45, together with its driving clutch plates '49, 62 and '65, function somewhat analogously to a centrifugal blower 'for'impelling a cooling-flowof'air outwardly'pas't the'friction clutch surfaces fori'pe'ripher'al discharge through the peripheral ports '48. The bolting flange 46 is spaced from the adjacent'face of the fly wheel 40'by boltinglugs 46 which define angularly spaced aircirculating'openings '46" thereb'etween, and a substantial outw'ard flow of air als'o occurs through these latteropenings. The web of the fiy wheel 40'is provided witharplurality' oftransverse ventilating holes 101 therein which assistin supplying air'to the central portion of the clutch structure. Angularly'sliape'd'openings 102 are also coredoutdn the rim' p'ortionof'the 'air cylinder 52 at angularly spaced points to augment an outward flow of air in this part'of theclutch structure.

The piston 53'has a relatively'large surface area responsive to the compressedairyso that a veryhigh clutching pressure can be exerted upon theclutch'surfaces and so that the clutch will be rapid'in its operation. These large pressures which arise from-a piston-area of large size can produce deformation of the'frictional clutch surfaces'in such'manner as to cause-uneven wear thereof. In order to avoid this, I have arranged the piston to apply its compressive stress to the clutch discs at a relatively small radiusyipe. the compressionforce exerted by the piston istransmittedthi'ough'theannulus 58 acting onthe pressure transmittin gr'ing59'at a"i'a'dius which is substantially smaller than the 'iadiusof' the'clutch surfaces which are active betweenthe driving and driven clutch elements. The pointof reaction ofthis compressive force is located at-a larger radius, -i. e. substantially at the bolting fiange 46 or substantially at the juncture of this flange with the drum portion 47. Thus; it willbeseen that the compression forces'act from-the ring 59 in-a diagonally outward direction toward the-bolting fiarige-46 Such diagonal line of thrust provides more uniform; pressure across the stem portion 111'.

faces of the friction clutch elements, because it causes the two plates 49 and 62 to deform in the same direction. In clutch constructions wherein the back plate is held at the inner edge and the front plate is spring loaded at the inner edge, I have found that when the friction discs are new there is contact only on about the inner third of the facings and the plates are about .015 further apart at the outer edges than at the center. In other words, we do not get a 100% bearing on the friction facings until they have worn down about of an inch at the inner edges of the discs. Torque tests have established that with the clutch as conventionally constructed, provided with new linings, we obtained approximately 4000# in. torque, but that when the plates were hollow ground the torque capacity increased to 5000# in. torque, due entirely to the fact that we then obtained approximately 100% bearing across the face of the linings. 1n the new construction herein shown we obtain this 100% bearing whether the faces be new or worn.

The compressed air cylinder 52 rotates continuously with the fly wheel and driving clutch elements, and the compressed air is admitted to and discharged from this cylinder through a relatively large port 105 entering the end of the cylinder axially. This port has an outwardly facing conical valve seat 105 against which is adapted to seat a large quick release exhaust valve 106 of the poppet type capable of eflecting a very quick release of the air from the cylinder in the clutch releasing operation. Mounted in this poppet exhaust valve is a spring loaded air inlet valve 107 which gives a retarded air admission to the cylinder 52 during the clutch engaging operation, as I shall later describe. The cylinder is formed with a forwardly extending annular lip or flange 108 surrounding the port 105, and secured to this lip or flange is an outwardly projecting hollow spindle or stem 111, which is supported from the flange 108 and is attached to the cylinder 52 by bolts 113 passing through a radially extending flange 112 and screwing into threaded inserts 114 carried by the cylinder. Thus, this tubular spindle 111 rotates continuously with the flywheel, clutch and cylinder assembly. Mounted externally on the tubular spindle 111 are spaced anti-friction bearings 115, 115' on which is sup ported a non-rotating housing assembly 109 comprising a rear housing portion 109a and a front housing portion 10911 secured together by cap screws 110. There is a running clearance between the rear housing section 109a and the continuously rotating flange 1118, so that the housing 7 is supported entirely by the anti-friction bearings 115,

115' carried on spindle 112. These bearings engage in a boss or hub portion 116 formed integral with the rear housing portion 1119a. Shoulders 117 and 118 on the housing assembly, and shoulder 119 and ring 120 on the tubular stem, coact with the bearings 115, 115 to lock the housing assembly 109 against endwise displacement from the rotating tubular spindle 111. A rotary seal. is established between the reduced outer end 111' of the rotating spindle or stem 111 and the outer stationary housing portion 10% by an O-type of sealing ring 121 which is set into a recess 122 in the housing portion 10912 and engages around the outer periphery of the reduced The outer housing portion 1119b is formed with an air inlet passage 123 receiving compressed .air from an air supply connection 124, which will be later described.

The poppet exhaust valve 106 which is carried by and rotates with the rotating tubular stem 111 comprises a valve head 126 which is mounted on a tubular shank 127. Extending radially outwardly from this shank 127 are guide fins or ribs 128 which have sliding guided engagement in a cylindrical guide bore 1111b of the tubular stem. The head 126 is secured to the shank 127 between the ends of the guide ribs 128 and a nut 129 screwing over the threaded end of the shank. The poppet valve head 126 carries an O-ring 139 which has a sliding fit within a pylindrical bore 131 extending inwardly from the radial flange portion 112 of the rotating sternlll. The valve head is formed with a beveled end face in which is mounted another O-n'ng 132 adapted to have seating abutment against the beveled seat 105 of the port 105. When this poppet exhaust valve 106 is in the open position illustrated, the air is free to discharge from the cylinder through the port 1135 and thence outwardly around the poppet valve through annular chamber area 133, within the annular flange 108, and then into annular chamber area 134 formed in the housing portion 10911. The annular chamber area 134 discharges to atmosphere through the downwardly opening port 135.

The spring loaded air inlet valve 107 normally closes an air inlet port 137 formed in the outer end of the tubular shank 127. in the open position of this inlet vaive the compressed air flows through port 137 and thence through the larger bore 138 of the tubular shank, into the compressed air cylinder through axial port 105. A substantially predetermined spring loading is given to the valve 1117 by a compression spring 139 mounted on the spring guide pin 140 projecting forwardly from the mounting block 1411a. A transverse pin 1411b passing through the block and through the tubular shank 127 mounts the block and guide pin within the tubular shank. As illustrative of the amount of spring loading which I find desirable to apply to the inlet valve 107, at least when using typical air pressures of from S0 to pounds per square inch prevalent in most shops, I proportion the valve 19! and its spring 139 so that the valve will not open untii a pressure of approximately ten pounds per square inch is effective against the valve. This entering pressure of the compressed air acts first on the poppet exhaust valve 1% for closing this exhaust valve before the inlet valve 111? is opened. That is to say, the rising increment of pressure of the compressed air entering through the rotating tubular stem 111 acts immediately on the relatively large area of the rear surface of poppet valve 1%, immediately shifting this valve over into seating engagement against the port seat before the pressure builds up sufficiently to open the inlet valve 107. This delay in opening the inlet valve gives the desired retarding or delaying action to insure that the clutch 31 will not be engaged until after the brake 32 is released, as will be later described. This interval of delay may be as short as a few hundredths of a second in the case of a machine rotating at speeds of 500 to 600 R. P. M. or so. When the rising pressure reaches this predetermined value capable of opening the inlet valve 107, the air thereupon flows through the bore 138 into the cylinder 52 for acting on the piston 53 to engage the clutch. The poppet exhaust valve 1% remains in engagement with the port seat 1115' as long as compressed air is maintained in the cylinder. Immediately upon release of pressure in the air line to the cylinder, the pressure of the air in the cylinder, augmented by the pressure of the clutch springs 92, 93 tending to restore the piston, exerts an outward shifting force on the poppet exhaust valve 106 for immediately unseating it from the port seat 105. The exhausting of the cylinder can thus occur very quickly through the port 1115, rotating annular chamber 133, stationary annular chamber 134 and outlet port 135, which are all of large diameter and of minimum length, so as to offer minimum restriction to the most rapid discharge of the air possible from the cylinder to atmosphere. Thus, it will be seen that the above described valve structure interposes an interval of delay in admitting the compressed air to the cylinder in the inlet part of the cycle, but discharges the compressed air from the cylinder in the shortest possible time during the exhaust part of the cycle.

Referring now to the improved brake mechanism illustrated in Figures 4 and 5, this brake mechanism is preferably of the V type wherein the rotating brake drum 141 is of substantially V-shaped cross section having outwardly sloping side flanges 142 and 143. As previously described, this brake 32 is preferably mounted on the crank shaft between the frame of the dieing machine and the clutch mechanism 31. This V type of brake is of very short axial length, considering its relatively large area of braking surface, and this short length lends the brake particularly to installation in the shortest amount of space possible between the end of the machine frame and the clutch mechanism. Moreover, this V type of brake, because of the wedging action between the sloping brake surfaces 142 and 143, can exert a relatively high braking action with the exertion of a relatively small gripping force between brake shoes. The web 144 of the brake drum 14-1 is secured to the crank shaft 24 in any suitable manner, such as by cap screws 145 screwing into a mounting flange 146 on the crank shaft. The brake shoe assembly is mounted upon a mounting plate 151 having the general outline shown in Figure 4, this mounting plate being secured to the frame of the dieing machine by cap screws 152, or in any other suitable manner. T he two arcuate brake shoes 155, 155', set diagonally with respect to the brake drum 141 for assembly reasons, have their upper ends mounted upon a common pivot pin 156 extending back through the mounting plate 151. The braking surfaces of these brake shoes 155, 155' have tapering or ii-shaped sides bearing friction material for establishing a wedging friction grip between the sloping side flanges 142, 143 of the brake drum. The other ends of the arcuate brake shoes have outwardly extending arm portions 158, and passing freely through apertures in these arms is a spring mounting rod 159. Mounted on the projecting outer ends of this rod are compression springs 161, 161 which transmit pressure to the outer sides 'of the arms 158 for normally holding the brake shoes in braking engagement with the brake drum 141. The outer ends of the compression springs abut against end stops or heads 162 and 163, the latter being adjustable on rod 159 by nut 164 for adjusting the pressure of the springs.

The'brake is adapted to be released through the actuation of a rocker arm 165 which is journaled on a pivot pin 166 'mounted'in a lower corner of the supporting plate '151. As shown-in Figure 5, this rocker arm 165 preferably comprises two'axially spaced plate portions 165a and 1651), and passing between these plate portions are pivot pins 167'on which are pivoted strut arms or links 168, 168. The outer ends of these strut links have ball formations 169 seating in spherical sockets 171 formed in blocks 172 which are set into the'ends of the brake shoe arms 1'58. Itwill'be obvious that clockwise pivoting of the rocker lever165 transmits an outward spreading force through'the strut links 168, 168' for releasing the arcuate brake shoes in opposition to the action of the compression springs 161, 161.

Such motion isadapted to be transmitted to the rocker member, in the brake releasing operation, through a push rod 175 extending'from a compressed air operated brake releasing chamber 176. The opposite ends of the rod 175 have similar internally threaded adjusting sockets 175a and 175b, and into the socket 175]) screws the threaded end 176 of a brake actuating rod 177. This rod has a rotative sliding fit in an apertured block 178 from which extends a pivot shank 179 having rotative mounting in a bearing bushing'carried in the lower arm of the bell crank lever 165. Abutting against one side of the apertured block 165 is a collar 180 which is pinned to the rod 177, and bearing against the other side of' this slide'block is one end of a compression spring 181 which has its other end bearing against another collar 132 pinned to therod. An adjusting handle 1S3 extending through the outer end of the rod 177 enables the threaded end 17.610 be screwed back and forth in the socket 1'75!) to adjust theposition of the collarlstl and slide block 178 to compensate for wear of the friction brake facings. The spring 181 serves to hold the rod'177 in each position of rotative adjustment.

"The brake cylinder 1'76'is preferably of the diaphragm type, comprising two housing sections 185 and 186 which are bolted together at 137 over the peripheral portion'of a diaphragm 138, preferably composed of neoprene or the like. The central portion of this diaphragm bears against a plate 189 from which extends a rod 199 having adjustable screw threaded engagement in the socket 175g in the left hand end of the push rod 175. A compression spring 191 is confined between the back side of this pressure plate 189 and the rear wall of the diaphragm chamber. Extending forwardly from this rear wall is a tubular member 192 which functions to guide the spring 191 and also to establish a limiting stop 193 for limiting the diaphragm movement. interposed between the back side of the pressure plate 189 and this end stop 193 is a stop pad 194 of rubber or neoprene which cushions the stopping of the inward thrusting motion of the diaphragm and push rod. Compressed air is transmitted to the front housing section 186 for acting on the front side of the diaphragm 183, through an air inlet fitting 196 which is riveted to the front housing section 1.86 and which mounts the automatically operating transfer valve 291, to be presently described. it will be seen from the foregoing that the brake stands normally engaged under the action of the compression springs 161, 161, and is only released when compressed air is admitted to the front side of the diaphragm 188 through the transfer valve 201.

In the operation of starting the punch press or dieing machine, compressed air is transmitted substantially simultaneously to the clutch engaging cylinder 52 and the brake releasing diaphragm chamber 176. As previously described, the V type of brake mechanism '32 requires only a relatively light spring loading to hold the brake effectively engaged, and the initial increment of air pressure acts first on this brake for releasing the brake before the clutch is engaged. That is to say, assuming a typical air pressure of 80 or 100 pounds, such as is prevalent in most shops, the first increment of pressure in the neighborhood of 10 pounds or so will be suflicient to release the brake but will not be suificient to engage the clutch, because of the spring loading of the air inlet valve 107 leading to the clutch cylinder'52, which retards or delays the engagement of the clutch, as previously described. Hence, the brake will be released before the clutch can be effectively engaged, which is a very desirable timed relationship in order to avoid overheating or burning of the clutch surfaces and brake surfaces. This relationship also facilitates inching the ram '26 downwardly under the control of the modulating valve 54, as will be later described.

Referring now-to the automatically operating transfer valve 201, shown in longitudinal section in Figures 6 and 7, the clutch engaging cylinder 52 and the brake releasing diaphragm chamber 176 both receive their compressed air substantially simultaneously from this valve. The valvestructure comprises a substantially cylindrical housing portion 2&2 from which extends the supporting flange portion 293 for bolting'to the inlet fitting 196 on the diaphragm chamber 176. A manifold passageway 204 in the housing has manifold communication with the diaphragm chamber 176 through the lateral port 205, and with the clutchv operating cylinder 52 through upper port 2G6. This upper port 206 is threaded for connection through suitable pipe fittings and pipe 207, 208, leading to one side of a suitable lubricator 209 (Figure l), the other side of which communicates through fitting 124 with the quick release valve-1&9 mounted on-the end of theclutch operating cylinder 52. Screwing into the left handend-of the valve housing 202 is aiming 210 which has connection through'pipe 211 with the modulating valve 34, and screwing into the right hand end of this valve housing is a fitting 212 which has connection with a solenoid operated master valve 213 preferably disposed in close proximity to the transfer valve 261, as shown in Figure 1, in order to minimize the time lag in the flow of'air-between the-two valves. The solenoid operated 9 master valve 213 responds electrically to the automatic timer mechanism 33, as will be later described. The two end fittings 210 and 212 both have semispherical seats 214 and 215 formed in their inner ends for seating a transfer ball 216 rolling therebetween. This ball rolls back and forth in a ball guide tube 217 having longitudinal slots 218 therein opening outwardly into the manifold passageway 264. interposed between the inner ends of the fittings or bushings 210 and 212 and the adjacent ends of the guide tube 217 are O-rings 219 which establish a very effective seal with the peripheral surface of the ball 216. As shown in detail in Figure 7, the inner ends of the fittings 210 and 212 are formed with lips 220 overlying the outer sides of the O-rings, and the ends of the guide tube 217 have similar lips 221 overlying the inner sides of the O-rings. When the ball is engaging against either spherical seat, the adjacent O-ring engages a diametrical plane of the ball and actually does the sealing between the ball and the housing. The inside diameter of the O-ring is smaller than the ball, so that some plastic deformation of the ring takes place. The lips 220 and 221 prevent the O-rings from being blown out of place.

As shown in Figure l, the master valve 213 receives compressed air through connection 222 leading from a compressed air tank 223, which is either supplied from a compressor or from the shop air line. The solenoid operated master valve 213 is preferably of the same general construction as is disclosed in my earlier application Serial No. 38,248, filed July 12, 1948, now issued as Patent No. 2,5 85,234. One preferred form of this valve is also commercially identified in the field as the Ross No. 734-N. C. solenoid control valve. This is a pilot type of very quick acting valve adapted to be opened by the energizing of a solenoid or electromagnet 224 disposed in the upper part of the valve assembly. It is not believed necessary to illustrate the details of this master valve, because of its disclosure in my copending application, and because it is a well known valve in this field.

Referring back to the transfer valve 201, it will be seen that when the solenoid operated master valve 213 is operated to transmit compressed air to the transfer valve through the right hand fitting 212, such air will blow the ball check valve 216 over into the left hand position illustrated, for closing the port 214 leading to the hand operated modulating valve. The compressed air thus admitted from the master valve 213 has direct and simultaneous access to the clutch cylinder 52 through line 2%, and to the brake operating chamber 176 through port 265. The ball 216 will remain in this left hand position, closing port 214, as long as no air pressure is transmitted from the modulating valve 34 to the port 214. When compressed air is transmitted from that valve through line 211, the ball check 216 is blown over to its right hand position for closing the port 215 leading to the solenoid operated master valve 213. When the ball is in this transferred position the compressed air from the modulating valve 34 has direct access through line 208 and port 225 to the clutch cylinder and to the brake releasing diaphragm chamber in the same manner that compressed air from the master valve 213 was transmitted thereto. The master valve 213 and modulating valve 34 are both open to atmosphere in their exhaust positions when the clutch operating cylinder and the brake operating chamber are not under pressure.

The solenoid energization of the master valve 213 is made responsive to timing mechanism indicated in its entirety at 225. This type of automatic timing mechanism is .fully disclosed in my aforesaid copending application, Serial No. 38,248, filed July 12, 1948, now issued as Patent No. 2,585,234, and hence a relatively brief disclosure thereof will sufiice in the present application. Figure 8 illustrates the main elements of this timing mechanism, the fundamental purpose of which is to control the closing and opening of a switch 226 for controlling the energization of the solenoid 224 of master valve 213. The switch responds to a switch actuating plunger 227 which is adapted to be depressed by a switch actuating lever 228 normally urged to an upper position by a spring 229. The swinging end of this arm carries a sharp edged nose 231 which rides on the periphery of a tripping wheel 232 preferably in the form of a ratchet wheel having ratchet cam teeth 233 characterized by sloping leading edges and relatively abrupt drop-off or trailing edges. The dotted circles 234 in back of this ratchet wheel denote a ball type of full-stroke detent mechanism coacting with the ratchet wheel, as fully disclosed in my aforesaid copending application.

initial movement to start the operation of the machine is transmitted to the ratchet wheel 232 through a Run or start pawl 237. The latter is mounted on the lower end of a plunger rod 238 extending up through a guide housing 239 and carrying a plunger head or knob 241 on its upper end. A compression spring 242 in the guide housing 239 normally holds the start pawl and plunger in their raised positions, and a spring pressed bushing 243 acting laterally on the pawl 2.37 holds the pawl nor mally pressed against the periphery of the wheel 232. Downward pressure exerted manually on the plunger knob 241 transmits a stepping movement to the wheel 232 for causing the fiat dwell of the next succeeding ratchet tooth 233 to depress and stop in engagement with the nose 231. This closes the switch 226 to energize the solenoid 224 of the master valve 213 and thereby start operation of the machine.

Referring now to the control which can be exercised over the tripping wheel 232 for securing the automatic one cycle stop operation, or for securing the continuous running operation, this latter control is exercised by a Stop pawl 251 which is mounted in the outer end of an eccentric follower arm 252. This follower arm constitutes part of an eccentric follower strap or ring which is mounted upon an eccentric 253 which rotates synchronously with the crank shaft 24. The eccentric is mounted upon a shaft 255 which has any suitable driven connection with the crank shaft, such as through a chain drive diagrammatically indicated in dotted lines.- in Figure 2 at 256. The stop pawl 251 is adapted to. deliver a relatively short stroke advancing movement to the ratchet Wheel 232, of just suflicient length to cause the flat upper dwell of the ratchet tooth 233 to ride out:

from over the nose 231 and permit the nose to swing up- The operativeness of this pawl 251 to engage the ratchet wheel 232 is made dependent upon a manual control which deterwardly to the switch opening position.

mines whether the pawl 251 has been shifted down to at low enough position to engage the teeth of the ratchet; wheel, or whether it has been raised to an upper position; where it will clear the teeth. This manual control, which; thereby establishes one cycle stop operation or repeat; operation, comprises a plunger rod 261 which passes upwardly through a guide housing 262 and carries an actuating knob or head 263 on its upper end. Rotativeiy mounted on the upper portion of the housing or sleeve 262 is a hub 264 having an actuating finger 265 extending therefrom, the rotative position of this hub and finger determining selectively whether the machine is to operate single stroke or continuously. Slidably mounted upon the rod 261 within the upper end of the housing 262 is a spring pressed head 267 having a spherical upper surface which enters a spherically formed cavity 269 in the hub 264. This head 267 has a transverse slot 271 extending down from its upper surface, and. engaging in this slot is a pin 272 which passes through the rod 261. A compression spring 274 is confined between the under side of this head 267 and an inwardly turned lip 275 at the lower end of the housing 262. The pressure of this spring 274 normally tends to hold the pawl nose 251 in a clear position where the substantially horizontal oscillations imparted thereto by the eccentric will not transmit any stepping movement to the ratchet wheel between this collar and the-under side of the head 267" is a smaller compression spring '277,*which is stifier than the outer spring 274. This inner spring 277'is adapted to hold the power driven, pawl nose 251 pressed down in operative engagement'against the ratchet wheel 232,

when the selecting hub 264 and thumb lever 265 have been rotated into; their single stroke position. The lever and hub are shown in their Repeat? position in FigureS, corresponding to a-repeating or continuous running operation of the machine. Forobtaining automatic single stroke operation; ,thc thumb lever 265 is revolved forwardlyto a position about l20 from the position shown in Figure 8. This forward rotation of the lever causes the hub 264 to move downwardly through the actionof a radial pin- 281 whichextends inwardly from the hub 264 into; an inclined slot 282 formed in the stationary guide housing 262. The resulting downward movement ofthe hub 264 forces the head 257 down along the rod 261 taking the pressure of the outer. spring 274'olf the rod 26.1 through cross pin;272, and compressing the inner spring 277 to transmit downward pressure through the collar 276 to the rod 261'for pressing the pawl 251 resiliently down againstthe ratchet wheel 232. The thumb lever and hub are yieldably held in each of these two rotated positions by a detent ball 284 mounted in the hubclland pressed by a spring 285 to snap .into conical depressions 286 in the guide housing 262, there being one of these depressions for the repeat position and another for the single stroke position of the hub and thumb lever.

The automatic timing mechanism .also includes adjusting means for advancing or retarding the timing of the stroke of pawl 251 with respect to the angular position of the crank shaft'24, so as to have the ram 26 come to rest almost exactly at the top of its stroke in the single stroke or one cycle stop operation. This adjustment is effected by rotatively-adjusting the clutching position of a dial ring 291 with respect to a driving pointer 292. The. pointer 292 rotates synchronously with the crank shaft 24through shaft 255, and has driving tips 293 at its ends,

normally engaging in a ring of V-shaped depressions 294 in the dial ring. The dial ring-291 drives the eccentric 253 which strokes the pawl 251. To effect a timing ad-v ment are fully set forth in my aforesaid copending application Serial No. 38,248.

Referring now to the hand operated inching or modulating valve 34,1 have illustrated in Figure the.

details of one conventional form of this valve now on the market, it being understood that, other embodiments The de. tails of construction and operation of this timing adjust:

or constructions of the same operating principle may be from the tank 223 or other source of supply is conducted through a pipe or flexible conduit 307 (Figure l) to-a.

supply port 308 which opens into an inlet chamber 309 formed in the lower housing section303. The pipe or duct 2l1 which extends to the transfervalve 201 has communication through lateral port 311 With an applica-.

tion chamber 312 formed in the intermediate easing section 392. Formed in the upper and intermediate housing sections is an exhaust chamber 313 which has exhaust communication with the atmosphere. The inlet flow of air from inlet chamber 30910 application chamber 312 occurs through-an inlet port 315 having a downturned valve seat316'formed in a tubular valve guide 317 having,

a mounting flange 318 clamped. between thecasingsections 302' and 303." R'e'ciprocably mounted in thctubular valve guide 317 is a double valve comprising an inlet valve 321 and .an exhaust valve 322; These twovalves are joined together by an axial stem 323, andsurround ing this stem is a compression spring 324 which normally tends to hold ,the inlet valve 321 pressed upwardly against the inlet port-315,;

Coacting withv the ,exhaust valve .322 is a movable exhaust port or seat 325atthe lowerend of an exhaust passageway '326 extending' up through. a pressure responsive piston element: 327; This piston element has a snug sliding yfit'within-a cylinder 328"which is maintained'at the same pressure "as the application chamber 312.. The piston element 327 is also made responsive to the oppose ing spring pressures exerted by a lower compression spring 331 acting upwardly-and a plurality of upper compression springs 332 acting downwardly, the adjacent ends of' these springs bearing against a radial flange 333. The exhaust -passageway"326 Opens outwardly through 1 ports 334 intothe exhaust chamber 313 above the flange 333: There are preferably three of the upper springs 332 located at'angularly spaced points on theupper side of the -flange'333; and having their upper ends bearing against the -under sideof the disc-shaped cam follower 335. Thiscarn follower is formed with a camtrack 336' which-bears upwardly against a disc-shaped circular cam 337 which is journaled in the upper casing section 301 for-rotation about the axis of the piston element 327."

Thc-canr-337 has a sloping cam face33$ which coacts with the cam track 336 to effect upward and downward displacemont'of the follower 335 for varying the effective pressure of the-upper springs 332. The rotatable cam is provided with a hub 341 which extends upwardly through a boss 342m the upper'end'of' the housing section 301,. and secured-tether upper end of the-hub 341 is the hub portion-343 'of -an operating-handle or driver 344.

Normally-this valve-34 stands in the position illus-' trated in FigurelO, with the air inlet port 315 closed by theinlet valve 321, and the application chamber 312 communicatingv with atmosphere" through-exhaust port 325. When it is desired to inch the ram26downwardly with: a slowcritically controlled movement, the handle 334 is moved gradually in a direction to depress the camfollower 335 and thereby-build upincreasing pressure in the springs. 332'. ln response -thereto,- the pressure re-' sponsive piston 327 moves downwardly and brings the exhaust port 325intoseating engagement with the exhaust valve 322,1thereby closing the exhausting passageways. Thereafter continued downward movementofthe double valve unseats the-inletvalve 321 from inlet port 315,;thereby admittingcornpressed air to the transfer valve 201.: This. admission of compressed air is main-'- tainerLat a regulated pressure which is predetermined bychamber 312 to fallbelow the predetermined minimum" results'in downward movement of the piston element and a widerropening-of' the inlet port 315." Thus, a very critically regulated pressure of any desired value can be transmitted from this modulating valve to the transfer valve and thenee to the clutch operating cylinder and' brake actuating chamber. Such critically regulated pres sure'remains the same as long as the 'valve handle 344 remains in the same position, which it will do until manu-' ally moved :-to another position.

ram 26'downwardly witha very slow movement. The rarn can be' stopped instantly atany point in this slow downward movement by backing the handle 344 back The sensitivity of the 1' controlvwhichcan be exercised through this modulating. valve-'enablestheclutch to be engaged momentarily with" hardly more than :a kissing" contact for moving the 13- into or toward its normal position. As previously described, this very slow inching movement of the ram head, which can be stopped at any desired point, is a very advantageous feature for setting dies, adjusting dies, or performing other operations preliminary to getting the machine set for production operation.

The single stroke operation and the repeating operation will be understood from the preceding description of the automatic timer mechanism 33, and from the disclosure in my aforesaid prior application, Serial No. 38,248, now issued as Patent No. 2,585,234. The setting of the thumb lever 265 predetermines whether the machine is to have single stroke operation or repeating operation. After the thumb lever has been set in the desired position, the machine is started by depressing the starting knob 24-1. If the thumb lever 265 has been preset for repeating operation, the power driven pawl 251 will reciprocate idly in its elevated position out of engagement with the ratchet wheel 232. On the other hand, if the thumb lever 265 has been set in the single stroke position the pawl 251 will be depressed into engagement with the ratchet wheel 232, so that the first stroke or cycle of operation of the machine will cause this pawl to stepthe ratchet wheel 232 through a one step movement for opening the switch 226 and thereby stopping the operation of the machine. My improved control mechanism hereindisclosed, when set for a single stroke operation, enables the ram 26 to be stopped within a few degrees of top dead center, without danger of a second or repeated strokes, even in dieing machines and punch presses operating at speeds of 500 or 600 R. P. M., or even higher. in the operation of stopping the machine, the clutch is released before the brake is engaged because the air has quick and easy discharge from the clutch cylinder 52 to atmosphere through the quick release exhaust valve 106, whereas the air exhausted from the brake operating diaphragm chamber 176 has to travel back through the transfer valve 201 and through the solenoid operated. valve 213 in exhausting to atmosphere. Also, the pressure drop in the brake operating chamber 176 has to be substantially completed before the brake springs can apply the brake shoes. Thus, the clutch is released before the brake is applied, but the over-all operation is so rapid that the above described performance can be obtained even at such high operating speeds.

While I have illustrated and described what I regard to be the preferred embodiment of my invention, nevertheless it will be understood that such is merely exemplary and that numerous modifications and rearrangements may be made therein without departing from the essence of the invention.

I claim:

1. In clutch and brake control mechanism for controlling the operation of a machine having a moving part adapted for single cycle or repeating operations at relatively high speeds, or for preliminary setting operations at relatively low speeds capable of being stopped substantially at any desired point, the combination of a compressed air operated clutch operative to drive said moving part, a compressed air operated brake operative to stop said moving part, electrically operated primary valve mechanism for admitting the compressed air at relatively high pressures to said clutch and to said brake for obtaining single cycle or repeating operations of said moving part, switch means controlling said electrically operated valve mechanism, timing means moving in synchronism with said moving part for controlling said electrically operated valve mechanism, manually actuated means for controlling said electrically operated valve mechanism, and a hand operated modulating valve for admitting compressed air to said clutch and to said brake at relatively low pressures for obtaining relatively low speeds of said moving part.

2. In clutch and brake control mechanism for controlling the operation of a machine having a moving part adapted for relatively high speed operation or for relatively low speed operation, selectively as desired, the combination of a compressed air operated clutch operative to drive said moving part, a compressed air operated brake operative to stop said moving part, primary control valve mechanism for admitting the compressed air to said clutch and to said brake when relatively high speed operation of the moving part is desired, secondary control valve mechanism for admitting the compressed air to said clutch and to said brake when the relatively low speed operation of the moving part is desired, and transfer valve means for connecting said primary valve mechanism to said clutch and to said brake under the condition of high speed operation and for connecting said secondary valve mechanism to said clutch and to said brake under the condition of low speed operation.

3. in compressed air operated clutch-brake control mechanism, the combination of a compressed air operated clutch, a compressed air operated brake, a primary control valve for admitting air to said clutch and brake at a relatively high pressure, a secondary control valve for admitting air to said clutch and brake at a relatively low pressure, and automatic transfer valve means responsive to the operation of either of said control valves for automatically transferring the connection of said clutch and brake from one of said control valves to the other in the selective operation of said control valves.

4. In compressed air operated clutch-brake control mechanism, the combination of a compressed air operated clutch, a compressed air operated brake, a primary control valve for admitting air to said clutch and brake at a relatively high pressure, a secondary control valve for admitting air to said clutch and brake at a relatively low pressure, and automatic transfer valve means responsive to the selective operation of either one of said control valves for automatically transferring the connection of said clutch and brake from one of said control valves to the other in the selective operation of said control valves, said automatic transfer valve means comprising a valve housing having two end ports communicating with said primary control valve and with said secondary control valve respectively, a manifold passageway intenmediate said end ports adapted to establish communication from either of said end ports to said clutch and brake, a ball valve adapted to roll between said end ports for selectively closing one and opening the other, and 0- type sealing rings adjacent said end ports adapted to have sealing engagement over the periphery of said ball.

5. in clutch and brake control apparatus for a punch press, dieing machine or the like having a reciprocating ram, the combination of a compressed air operated clutch operative to drive said ram, a compressed air operated brake operative to stop said ram, main control valve mechanism for admitting compressed air to said clutch and to said brake in the normal running of the machine, said main control valve mechanism comprising manual means for operating said valve mechanism and automatic timer means responsive to the movement of said ram for operating said valve mechanism, and secondary control valve mechanism responsive to manual operation for admitting a closely modulated pressure to said clutch and to said brake for moving the ram in slow inching movement'fordie setting purposes and the like. said secondary valve mechanism comprising an appiication chamber connected to said clutch and to said brake, movable pressure responsive means responsive to the pressure in said application chamber, an exhaust port for exhausting air from said application chamber, said exhaust port moving With said pressure responsive means, an inlet port for admitting compressed air to said application chamber, a double valve element controlling said outlet and inlet ports, primary and secondary springs acting in opposition on said pressure responsive means, said primary spring normally tending to move said pressure responsive means in a direction to open said exhaust port, and manually, operated cam mechanism .operative to increase the effective pressure of said 'seconda'ryispring to move said pressure responsive means in a direction to close said exhaust port and to open said inlet-port.

6. In clutch control mechanism for usein a punch press, the combination of a clutchoperative to drive the crankshaft of said press, compressed 'air power means forcontrolling said clutch, a brake for stopping the crank shaft. of said' press, compressed air power. means for controlling said brake, an electrically,controlled-valve for controlling the application of'compressed air to both of said.power means, a switch controlling .said valve, a

ratchet WhCBlfOl actuating said switch, a start-pawl foradvancing said ratchet wheel to one .switchlactuating position, a stop-pawl for advancing .saidratchet wheel to another switch actuating position, synchronizing means for causing said stop-pawl to have an operating stroke synchronously with said crankshaft, manual means for determining whether said stroke shall .be .operative to advance said ratchet wheel, .and .a springdoadedvalve associated wtih the: compressedair power means that control said clutch for delaying theengagementof said clutch until after said brake. has been released.

7.'Inclutch control mechanism. fora machine-characterized by a driven member adaptedtohave a onecycle stop motion,. the combinationof .a clutch adapted to drive said driven member, fluid pressure power means for controllingsaid clutch,.a brakeuadapted to stopsaid driven member, separate fluid pressure power means for controlling said brake, a rotatable. control-wheel, means responsive to movement of .said control wheel for controlling both of said fluid pressure power means, a startpawl for actuating said control wheel to a clutch-engaging and brake releasing position,a stop-pawl for actuating said "control Wheel to a clutch releasing andbrake engaging position, means for transmitting motion-from said driven member to said stop-pawl, and -a hand operated modulating valve for admittingcompressed airto both of said fluid pressure powermeans-at relatively low pressures for producing a slow motion of said driven motion from said driven member to said stop-pawl, a

stop push button connected to shift the plane of said stepping motion between an idlingposition where the stop-pawl is ineffective to actuate said control wheel, to an operative position where the stop-pawl is effective to actuate said control wheel, and a preselecting control capable of being preset by the operator for shifting said stop .push button to such latter position, said preselecting' control comprising guide means for saidstop push button, a rotatable hub carried by said guide means adapted to be rotated to different selected positions thereon, pin and inclined slot means coacting between said rotatable huband said guide means for causing said hub to shift axially of said guide means in such rotative movement, and spring means responsive to such shifting movement of said hub for moving said stop-pawl into its operative position.

9. In clutch and brake control mechanism for dieing machines, punch presses and other like machines characterized by a crank shaft transmitting reciprocating motion to a ram, the combination of a spring released friction clutch for driving said crank-shaft, a compressed air operated cylinder and piston associated with said clutch for engaging the clutch, a spring-engaged brake for stopping the rotation of said crank shaft, compressed air operated means for releasing said brake, an electrically operated valve for admitting compressed airto said cylinder and piston and to said brake-actuating means during one-cycle stop operation and during continuous running operation of the 'machine,-a manually operated inching valve for admitting compressed air atreduced pressures to said cylinder and piston :and tosaid brake actuating means for inching the ram with a slow'movement during die setting operations and the like, an automatically operatingtransfer'valve comprising a manifold connection leading to said compressed air cylinder and piston and to said brake actuating means, two oppositely disposed ports for admitting air to said manifold area from said electrically operated valve and from said hand operated inching valve, a balla-dapted to roll from 'one to the other of saidoppositely disposed inlet ports to effect an automatic transfer function therebetween, a spring loaded air inlet valve interposed between said transfer valve and said compressed air'cylinder and piston for delaying the engagement of said clutch until after the brake is released in starting the operation of the crankshaft, a switch controlling said electrically operated valve, a rotatable control wheel, means responsive to movement of said control wheel for controlling said switch, a manually operated start-pawl for actuating said control wheel to a clutch engaging and brake releasing position, a stop-pawl for actuating said control wheel to a clutch releasing and brake engaging position, and means for transmitting motion from 'said 'crank shaft to such stop-pawl.

References Cited in the file 'of this patent UNITED STATES PATENTS 1,979,488 Perez Nov. 6, 1934 2,023,597 Klocke et al. Dec. 10, 1935 2,120,798 Criley -June-14, 1938 2,133,161 Colbert Oct. 11, 1938 2,193,880 Peet" Mar. 19, 1940 2,210,227 Williamson"; Aug. 6, 1940 2,214,201 Moulder Sept. 10, 1940 2,270,431 Freeman Jan. 20, 1942 2,277,554 McCoy; Mar. 24, 1942 2,308,299" Page Jan. 17, 1943 2,360,489 Gillett' Oct;'17, 1944 2,559,195 May" 2 July 3, 1951 2,581,637 Donleyetal.' Jan. 8, 1952 2,585,234 Eason Feb. 12, 1952 2,589,059 Crookston" Mar. 11, 1952

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