US3082605A - Power driven tools - Google Patents

Description

March 26, 1963 P. c. NELSON 3,032,605

POWER DRIVEN TOOLS Filed Jan. 4, 1960 3 Sheets-Sheet 1 In a IN VEN TOR. PAUL C. NELSON ATTORNEYS March 26,1963 P. c. NELSON 3,082,605 POWER DRIVEN TOOLS Filed Jan. 4, 1960 3 SheetsSheet 2 FIG. 2 H

51 5| I47 40 I2 52 R g 9| 5a 47 5a 92 4| E 52 l 0 4r JNVENTOR. PAUL c. NELSON BY ATTORNEYS March 26, 1963 P. c. NELSON 3,082,605

POWER DRIVEN TOOLS Filed Jan. 4, 1960 3 Sheets-Sheet 5 FIG. 4

INVENTOR. PAUL c. NELSON ATTORNEYS 3,082,605 POWER DRIVEN TOOLS Paul C. Nelsen, Lake City, Minn, assignor to ONeil- Irwin Manufacturing Company, Lake City, Minn., a corporation of Minnesota Filed Jan. 4-, 1960, Ser. No. 393 1 Claim. (Cl. 60-97) The herein disclosed invention relates to power driven tools and particularly to a hydraulically operated tool such as disclosed in the patent to Paul C. Nelson for Power Driven Tools, Number 2,875,733, issued March 3, 1959.

An object of the invention resides in providing a construction by means of which the ram can be made to travel toward the bed at either of two speeds determined by the operator and by which either of two degrees of pressure can be procured at any position of the ram.

Another object of the invention resides in providing a construction in which two rotary hydraulic motors are employed having expansible chambers of different capacities and operating cranks or eccentrics to reciprocate the ram.

A still further object of the invention resides in connecting the motors to a common crank shaft operating the ram.

An object of the invention resides in providing a control system for controlling the flow of fluid to and from the motors and in which fluid under pressure is at one position of the control connected to the motor of lesser capacity to effect rapid movement of the ram, and in another position the fluid under pressure is connected to both motors to reduce the rate of movement and increase the pressure on the ram.

Other objects of the invention reside in the novel combination and arrangement of parts and in the details of construction hereinafter illustrated and/or described.

In the drawings:

FIG. 1 is a side elevational View of a power driven hydraulically operated brake.

FIG. 2 is a fragmentary sectional view taken on line 22 of FIG. 1 and drawn to a greater scale.

FIG. 3 is an elevational sectional view taken on line 3-3 of FIG. 2 and drawn to the same scale as FIG. 2.

FIG. 4 is a diagrammatic view of the invention.

FIG. 5 is an elevational view of the control mechanism shown in FIG. 1 and drawn to a greater scale.

FIG. 6 is a cross sectional detail view taken on line 6-6 of FIG. 5 and drawn to a greater scale.

FIG. 7 is an elevational view of the switch with the cover removed.

For the purpose of illustrating the invention, a hydraulically operated press brake, such as illustrated in the above noted patent, has been shown. This brake consists of a frame A having two vertical side frame members 10 and 11 constructed of plate steel and cut to the form shown. These side frame members are secured together at the upper ends by means of two transverse rods 12. The ends of these rods are reduced in diameter and extend through said side frame members and nuts 13 secured on the ends of said rods hold the said members attached to one another at their upper ends in spaced relation. At the lower ends of the frame, two crossbars 14 are employed. These bars are secured to said frame members by means of cap screws 15. A shelf 16 extends across said frame members and rests upon said crossbars and is similarly secured thereto.

Overlying the forward edges 19 of the frame members 10 and 11 is a bed B which consists of two parallel plates 22 and 23. These plates are held separated from one another by means of bars 24 and 25 situated at the ICC upper and lower edges of said plates. These bars have tongues 26 extending between said plates and which hold the same in spaced relation. The said bars may be Welded or otherwise secured to the plates 22 and 23 so that the entire bed will move as a unit. Cap screws 27 extend through slots 28 in said plates and are screwed into the members 10 and 11 at the edges thereof. These cap sc'ews hold the bed B in proper adjusted position with reference to frame A. The bar 24 is formed with a groo're 29 in which may be mounted difierent tools for the use of the machine. The bed B may be raised and lowerel by means of a raising device 32 which, forming no particular feature of the invention, will not be described in detail.

Situated above the bed B is a ram C. This ram consists oi a transverse bar 33 which has Welded to it at its ends bosses 34. These bosses slide on vertical guides 35 welded to lugs 36 extending outwardly from the forward edges of the frame members 10 and 11. The foremost end of the bar 33 is formed with a clamp 37 by means of which various types of tools may be attached to the ram.

The ram C is operated by means of two eccentrics 41 attached to a shaft 42 best shown in FIGS. 2 and 3. Shaft 42 is journaled in bearings 46 mounted in the vertical frame members 10 and 11. Eccentric straps 43 encircle said eccentrics and are pivoted to pins 46 attached to lugs 45 on the bar 33 of the ram. As the shaft 42 turns the eccentrics 41 are correspondingly turned and the eccentric straps 43 raise and lower the ram C.

The shaft 42 forms part of two hydraulic motors D and E which are similar in construction. Only the motor D will be described in detail. This motor includes a case 47 having a central section 49 formed with a cylindrical bore 48. Shaft 42 extends centrally through this section of the case. The case is further constructed with end walls 51 bolted to said case by means of cap screws 52. These end walls have bearings 53 in which the shaft 42 is journaled. The case 47 is held from rotation relative to the frame A by means of ears 54 formed on the end walls 51 and through which the rods 12 previously referred to extend. By means of this construction, .an annular chamber 55 is formed within the bore 48 and which is divided into two compartments 56 and 57 by means of a partition 58 secured to the section 49 and a piston 59 secured to the shaft 42. The shaft 42 may rotate until the piston 59 reaches the partition 58 on opposite sides thereof. During such movement, the eccentric 41 raises and lowers the ram C. A passageway 85 disposed adjacent partition 58 on one side thereof communicates with the compartment 56 while a passageway 86 adjacent said partition on the other side thereof communicates with compartment '57.

For the purpose of operating the motors D and E, a pump 60 is employed, which is provided with a body 62. A bracket 63 is attached to this body by means of cap screws 61 and has a flange 64 which is bolted to the shelf 16. This pump includes a vane type rotor 65 operable in a chamber 66 having an inlet 69 and an outlet 63. The inlet 69 is connected to an oil reservoir 69:: and which is bolted to the body 62. Rotor 65 is driven by an electric motor mounted on the shelf 16 but not shown. The output of pump 61 is controlled by a valve mechanism 70. This valve mechanism includes a bore 71 which is horizontal and in which is slidably mounted a valve member 72. The body 62 is formed with a passageway 73 which communicates with the outlet 68 of the pump and which also communicates with a manifold port 74. This port is in communication with the bore 70 at the lower side thereof. The body 62 is further formed with two other ports 75 and 76 also communieating with the bore 71 but on the upper side thereof. These ports are spaced from one another. The body 62 is further formed with ports 83 and 84 which are disposed opposite the outer ends of the ports 75 and 76 and which communicate with the bore 71 on the underside thereof. These ports communicate with passageways 38 and 89 which lead to the reservoir 6%. The valve member=72 is formed with a valve rod 78 which passes through a gland 79 attached to the body 72. The said valve member fits snugly within the bore 71 of the valve and is formed with two grooves 51 and 82 which, when the valve member is in central position, lie between the ports 75 and 76. By means of these grooves the valve members are formed with port closures 85 and 86, said closures being at the end of the valve member. When the valve member is in central position, as shown in FIG. 4, the closures 85 and 86 lie opposite the ports 75 and 76 and block the flow from the manifold 74 to either of these ports and also isolate ports 33 and 84'from ports 75 and 76.

The motor E is of the same diameter as the motor D but the center section 149 of the case 147 of this motor is longer than the center section 49 of motor D and hence requires greater volume to operate. This motor is constructed and mounted in the same way as the motor D and the description thereof will not be repeated. The rotors of both motors are fixed relative to the shaft 42 and the pistons thereof travel in unison with one another. The end walls 51 of said motors are secured to the rods 12. If desired, the shaft 42 may be made in two sections 91 and 92 which are splined together by means of a connecting sleeve 93. The pistons of the two motors occupy the same relation with respect to the partitions in the same so that when one piston reaches one side of the partition in the cylinder in which it operates the other piston also reaches the corresponding partition on the same side.

Operating in conjunction with the two motors E and D is a valve '90 which has a body 94 constructed with a bore 95. Formed in the body 54' are ports 101, 102, 103 and 104. Slidable in the bore 95 is a plunger 96 which has two grooves 07 and 93 formed in the same. By means of this construction three port closers 105, 106 and 107 are formed. The plunger 96 is further constructed with a valve rod 108 which passes through a gland 109 on the end of the body 94. A spring returned solenoid 110 connected to the valve rod 108 serves to move the plunger 96 to the left as viewed in FIG. 4. A compression coil spring 149 acting against the end of the valve rod 108 returns the valve member to normal position. The solenoid 110 and the valve '90 are attached to a bracket 143 clamped on the rod 12.

The two ports 75 and 76 are connected by means of piping 111 and 112 to the passageways 85 and 56 of the pump '13. Ports 75 and 76 are also connected by means of piping 113 and 114 to the ports 101 and 102 of valve 90. The ports 103 and 104 of valve 50 are connected by means of piping 115 and 116 to the passageways 85 and 86 of the motor E.

For controlling the operation of the tool, a control mechanism F is employed which is shown in FIGS. 1, 5, 6 and 7. This controlmechanism includes a slide bar 201 mounted for sliding movement in two guides 202 secured to the side frame member 10 by means of bolts 203. Thisslide bar is bifurcated at its end to-receive a roller 204 journaled for rotation on a pintle 205 extending through said roller and bar. .Roller 204 serves as a cam follower and engages a cam 206 mounted on shaft 42. The bar 201 is urged into contact with-the earn surface 207 of cam 206. by means of a tension coil spring 208 anchored at one-end to a pin 209 secured to the outer end of the bar 201 and to ascrew 211 secured to the frame member 10. Y

Overlying the upper edge 212 of the slide bar 201 is a cam plate 213 having a cam surface -214. This plate is provided with a flange 215 which underlies the lower edge 216 of said bar and a web 217 (FIG. 6)- which overlies the rear surface 218 .of said bar, and is connected to said cam plate and flange. This construction permits of slidably supporting the cam plate 213 relative to the bar 201. Overlying the upper edge 212 of bar 201 and at a locality between the cam plate 213 and the roller 204 is another cam plate 219 which has a cam surface 221. This cam plate is spaced from the edge 212 to provide a space 222 therebctween and which receives the cam plate 213. The cam plate 219 has issuing downwardly from it a flange 223 which overlies the forward surface 224 of the bar 2521. This flange is attached to said bar by means of screws 225 which pass through said flange and are screwed into the bar proper. Overlying the forward surface 224 of bar 201 is a pointer 226 which is adapted to register with a scale 227 overlying the surface 224 of bar 201 and secured thereto. Pointer 226 has a flange 228 issuing upwardly therefrom and which also overlies the surface 224. The flange 228 and the flange 217 have aligning holes 230 and 231 therein and which register with a slot 232 in the bar 201. A bolt 233- extends through said holes and slot and serves to clamp the pointer 226 and the cam plate 213 in fixed position relative to the'bar 201.

The two cams 214 and 221 operate an electric switch mechanism 240 shown in detail in FIG. 7. This switch ,ries a boss 252 which is-bored as indicated at 253 to form a'guide for a cylindrical cam follower 254. This cam follower is adapted to engage the cams 214- and 221 and to be raised thereby to operate the switch 240.

The switch mechanism 240 includes a sensitive switch proper indicated by the reference numeral 255 and which is known in the trade as a micro switch. This switch has an operating button 256 which, when depressed, serves to close the switch. The switch is spring returned and the button 255 and the switch mechanism returns to normal open position when pressure on the button is released. The switch 255 is attached tothe back 242 of case 241 by means of screws 257. The button 256 is depressed by means of a lever 260 which is rotatably and slidably mounted on a pin 259 secured to the back 242. For the purpose, the lever 260 has flanges 261 extending outwardly therefrom which are provided with slots 262 and which receive said pin. A tension coil spring 263 is anchored at one end to the lever 260 and at its other end to a bracket 264 secured to the end wall N1 of case 240.

The lever 260 is operated by means of la plunger 270. This plunger is slidably mounted in a guide 271 attached to a partition 272 formed in the case 240. The said guide extends through and is attached to the wall 244 and the portion 273 thereof disposed beyond said wall is enclosed by means of rubber bellows 274 attached at one end to said plunger and at its other end to a boss 275 issuing outwardly from the end wall 244 of case 240. This bellows excludes moisture from the interior of the case 240 and maintains the parts in working order. The plunger 270 is urged into its outermost position by means of a compression coil spring 265 which is slidably mounted on a stud 266 attached to the wall 241 of case 240. This stud enters a cavity 267 in the end of the plunger 270.

The cam follower 254 has a threaded shank 276 which is screwed into the outer end of the plunger 270 and which may be raised and lowered by means of the same. This plunger is held in adjusted position relative to the plunger 270 by means of a lock nut 277 also screwed on the same. The plunger 270, at a locality between the partition 272 and the end wall 244 of case 240, is formed with a cam 280 having a notch 231 and cam surfaces 282, 283 and 284adjacent thereto. These cam surfaces are adapted to engage a roller 285 pivoted to the flanges 261 on lever 260 and which forms a cam follower for engagement with the cam 280. It will be noted that when the cam follower 254 is raised that the roller 285 rides on the surface 282 of cam 280 and due to the pin 259 being at the lower end of slots 262, causes the button 256 to be depressed and the switch mechanism to be operated. When the cam follower 285 reaches the cam surface 283 the same dwells thereon and holds the switch in closed position. When, however, the roller 285 reaches the surface 284 switch 255 is again opened. When the plunger 270 is moved in the opposite direction, the shoulder 286 formed between the cam surfaces 282 and 284 moves the lever 260 in a direction toward the wall 244 and causes said lever to slide on the pin 259 along slot 262. The said slot being inclined withdraws the roller 285 from engagement with said shoulder, and when the plunger reaches its normal position lever 26% is free and spring 263 draws the lever back to the position shown in FIG. 7. During the return movement of the plunger, lever 260 fails to depress the button 256 and switch 255 remains open.

The solenoid 110 is energized by an electric power line comprising conductors 287 and 288 which are connected to any suitable source of electric energy. A conductor 289 is connected to the conductor 287 and to one terminal of the solenoid 110. The other terminal of said solenoid is connected by means of a conductor 291 to one side of the switch 255. The other side of said switch is connected by means of a conductor 292 to the other conductor 288 of the line.

The method of operation of the invention is as follows: The position at which the ram reverses is determined by the valve mechanism 70 as disclosed in the patent referred to. The speed at which the ram travels is controlled by the control mechanism F and the valve 90. Since the structure for operating the valve mechanism 70 is well described and its functions clearly brought out in said patent, the same will not be repeated, and it will be assumed that the ram is set to operate within predetermined limits as brought out in the patent. When the cam follower 254 engages edge 212 of the sliding bar 201, the parts of the switch mechanism 240 are disposed as shown in FIG. 7 and the switch is open. With the switch open, solenoid 11G occupies the position shown in FIG. 4, and the plunger 96 of valve 90 also occupies the position shown in FIG. 4. In this figure it will be noted that the port closers 105 and 106 cover the ports 101 and 102 and cut off the motor E. When plunger 72 is moved toward the left, as seen in FIG. 4, the port 75 is brought into communication with groove 81 and also with manifold 74. Also port 76 is in communication with port 84. The fluid then flows through pipe 111 and into compartment 56 of motor D and from compartment 57 through pipe 112 to port 84 and from there on to the reservoir 69a. This causes the piston 59 to move away from partition 58 and the shaft 42 to turn in a counterclockwise direction. The ram now descends. As the shaft 42 rotates, cam 206 engaging roller 204 on slide bar 201 moves said slide bar to the right. As the cam surface 214 engages the cam follower 254, the same is raised and the plunger 270 moved upwardly. This causes the roller 285 of switch mechanism 240 to ride along the cam surface 282. Lever 260 now swings on pin 259 and depresses button 256 closing switch 255. Switch 255 being connected to solenoid 110 energizes the same and the valve rod 108 is drawn into the solenoid moving the plunger 96 toward the left until the port closer 106 lies immediate the ports 103 and 104. In this position, pipe 113 is in communication with pipe 115 and pipe 114 is in communication with pipe 116. Both motors D and E are now connected to the source of fluid under pressure and to the sump. The combined displacement of the two motors being greater than that of motor D, the shaft 42 now rotates at a greatly reduced rate of speed. This movement continues until the cam follower 254 engages cam surface 221 of cam plate 219 after which the roller 285 drops behind the shoulder 286 of cam 280'. The switch 255 now opens and solenoid is deenergized and spring 149 returns the plunger 96 back to normal position as shown in FIG. 4. During the return stroke of the ram, shoulder 286 engages roller 285 and causes lever 260 to slide along slot 262. This slot being inclined, roller 285 is withdrawn from engagement with shoulder 286 and spring 263 moves the same back to normal position as shown in FIG. 7. During such movement, the button 256 is not depressed and only the motor D is energized. The ram hence returns at a rapid rate. It will readily be comprehended that the cam surface 214 may be set at any position within limits relative to the slide bar 201 by means of the bolt 233, the pointer 226 and the scale 227 which move with cam plate 213 and which is graduated to indicate the position of the ram at which slow motion commences.

The advantages of the invention are manifest. The ram always returns at high speed [and throughout its descent may be switched over to low speed at any desired position, thus more operations can be performed in a given length of time. The construction utilized is extremely simple as compared to that heretofore employed and is positive in action. The setting of point at which change from high to low speed is procured can be quickly accomplished and is simple to procure. The apparatus can be constructed at a minimum cost.

Changes in the specific form of the invention, as herein described, may be made within the scope of what is claimed without departing from the spirit of the invention.

Having described the invention, what is claimed as new and desired to be protected by Letters Patent is:

In a power driven tool having a movable tool support, actuating means for moving said tool support, a first hydraulic displacement motor having a movable member for moving said actuating means and provided with two compartments one on each side of said movable member, a second hydraulic displacement motor having a movable member for moving said actuating means and also provided with two compartments, one on each side of the movable member thereof, said second motor having greater displacement than said first motor, an actuating valve mechanism connected to a source of fluid under pressure and a sump, conduits connected to said valve mechanism and to the compartments in said first named motor, a valve member in said valve mechanism movable in one direction to connect one compartment of said first named motor with the source of fluid under pressure and the other compartment of said first named motor with the sump and vice versa, a speed control valve having passageways, conduits connected to said passageways and paralleling said first named conduits, said speed control valve having other passageways and conduits connected thereto and to the compartments of said second motor, said speed control valve having a valve member movable into a position to close both of said second named passageways and to short circuit said third named passageways to deenergize the second named motor and further movable into a position bringing the corresponding first and second passageways into communication to deliver liquid under pressure to the corresponding compartment of the second motor and to connect the other compartment of the second motor with the sump, the combination of a solenoid controlling the movement of the valve member of said speed control valve, a switch having an operating button, a lever engaging said button and having a slot therein, a pin extending through said slot and on which said lever is pivoted, said lever when in one end of the slot serving to depress said button and when in the other end of said slot failing to move said button, a plunger slidable in a direction normal to the movement of the button, said plunger having a cam thereon serving when moved in one direction to swing said lever to operate said switch when the pin is in the first named end of the slot, said plunger having a shoulder References Cited in the file of this patent engaging said lever and when moved in the opposite di- UNITED STATES PATENTS rection moving said lever to bring said pin into the other end of the slot, resilient means returning said lever to g May 1939 arker May 30, 1944 bring the pin mto the first named position of the slot, and 5 2 603 145 D reis July 15 1952 a cam operated by said shaft and engaging said plunger, 3 6 Hm Feb 1957 said cam being adjustable to operate said plunger at vari- 2:825:30? T 1958 OHS Positions of Said Shaft. 2,860,571 Hatch Nov. 18, 1958

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