US2745320A - Actuator - Google Patents

Description

May 15, 1956 Filed Jan. 14, 1955 W. GROEN ACTUATOR 4 Sheets-Sheet l INVENTOR: WI LLEM GROEN W. GROEN May 15, 1956 ACTUATOR 4 Shets-Sheet 2 Filed Jan. 14, 1953 INVENTOR: WI LLEM G ROEN I ATT'YS May 15, 1956 w. GROEN 2,745,320

ACTUATOR Filed Jan. 14, 1953 4 Sheets-Sheet 5 INVENTOR. WILLEM GROEN BYZ ATT'YS W. GROEN ACTUATOR May 15, 1956 4 Sheets-Sheet 4 Filed Jan. 14, 1953 INVENTOR. W I LLE M G R 0 EN ATT'YS United States Patent ACTUATOR Willem Green, Chicago, 111., assigno'r to Gnsrud Machine Works, Inc., Chicago, 111., a corporation of lllinois Application January 14, 1953, Serial No. 331,233

7 Claims. (Cl. 9G14) This invention relates to milling machines, and has particular reference to actuating mechanism for controlling high-speed routers and drills carried by articulated radial arms for movement to any point upon the surface of a Work-holding bed.

The main objects of this invention are to provide improved actuating mechanism for raising and lowering the tool-carrying head between an inactive elevated position and a lower operating position; to provide an improved form of mechanism of this kind wherein the operating head is automatically lifted by power-driven jack mechanism and drops by gravity at a controlled rate to its oper ating position; to provide an improved arrangement of devices for automatic control of such actuating mechanism by the finger of the operator while his hands are in position'for guiding the milling Work in which the machine is engaged; to provide an improved combination of jack mechanism and dashpot mechanism for raising and lowering the milling head; and to provide improved means whereby the jack may be selectively adjusted to add force to the descent of the milling head or to otter no assistance.

Ajspecific embodiment of this invention is shown in'the accompanying drawings in which:

Figure 1 is a perspective view of a radial arm drilling machine constructed according to this invention.

Fig. 2 is a front elevation of the drill carrying head of the'device of Fig. 1 with the lever arms of the guide handle shown partly in section on the line 22 of Fig. 1.

Fig. 3 is a side elevation of the tool carrying head together withforearm portion of the supporting frame, the latter having its door plate removed to disclose the actuator mechanism that is housed within.

Figs. 4 and 5 are similar diagrammatic views of the electrically controlled valves and pneumatic pipe system for effecting the reverse movements of the jack which actuatcs the mechanism for lifting the milling head.

- Fig.6 is a top plan of the actuator mechanism with some of the related parts shown in section.

Fig. 7 is a side elevation of the same with the jack cylinder shown in longitudinal section.

Fig. 8 is a vertical axial section of the dashpot, taken on line 8-8 of Fig. 6.

Fig. 9 is a horizontal section of the handle which guides the operating position of the milling tool, showing the mechanism for push button control of the electric switch for the valve control mechanism shown in Figs. 4 and 5.

'ln the-form shown in Fig. 1, the particular form of toolcarrying milling head and guide arms are of a design suitable for drilling operations, but it is to be understood that the invention is equally applicable to the routers, involving mere changes-in the form of the guiding handles for greater visibility and changed location of the switch-actuating buttons.

The use of high-speed spindles, for routing and drilling stacked sheets-of non-ferrous metals, is a proven and accepted practice. By this method sheets to be cut are stacked on a table and as'm'any templates as possible are nested side by side on top of the sheets and secured to the table, allowing spaces between the templates to accommodate the diameter of the pattern follower. It is to this type of machine that the present invention is particularly directed. p

In the form shown in Fig. l, the milling head 10 comprises motor and the tool-driving spindle. The head 10 is vertically slidable on a supporting carrier frame, which comprises horizontally extending arms 11 and 12 swingable about a vertical bearing 13, and articulated on one or more intermediate vertical axes 14, whereby the milling tool which in the drawings is shown as a drill 15, may have universal horizontal movement to any position over the surface of a table 16 on which the Work that is to be operated upon is clamped or otherwise fastened. The supporting frame is similar for both drilling and routing operations, and the difference between the routing and drilling structures resides mainly in the structure of the head 10 and milling tool, with incidental changes in the operating handles and motor speeds.

The actuating mechanism for effecting the up and down movements of the head 10 is housed within the interior of the hollow forearm member 11 of the articulated frame that carries the head.

In the form shown, the front end of the forearm portion 11 has vertical guideways 17 which coact with a guide rib or base member 18 for accurate vertical sliding movement of the head it integrally mounted on the member 18 is a lug 19 that is pivotally connected to a pair of links 2t which in turn are pivotally connected to one arm of a bell crank lever 21 which is pivoted betweenlugs 22 on a base frame 23 within the arm 11. The other arm 21.1 of the bell crank lever 21 is forked to embrace traveler block 24 and has bearings for trunnions 25. The block 24 is slidable on the piston rod 26 of the cylinder 27 of a fluid actuated or pneumatic jack. This cylinder is pivoted by trunnions 23 on spaced lugs 28.1 on the base- Also, pivotally mounted on the trunnions 25.

For most operations, this actuating mechanism raises the milling head it to an elevated position by means of the pneumatic jack 27 and then allows the headli) to descend by gravity at a rate controlled by the dashpot 32. The piston rod 26 of the jack has a fixed shoulder or head 34 which en ages the block 24 whenthe piston 35 of the pneumatic jack is riven toward the left of Fig. 7. The rod 26 is freely slidable in the block 24 so that during reverse movement of the piston 35 the rod has overrunning relation to the block 2 3, and the head 34 can shift to the position 34.1, as indicated by broken lines in Fig. 7, so as to free the milling head 10 to fall by gravity at a speed controlled by the dashpot 32.

In order to provide for circumstances in which it might be desirable to use extra pressure to force a drill into the work, by adding the power of the jack 27 to the weight of the milling head 19, the block 24 is provided with a set screw 36 that can be advanced from its normal position to engage an angular groove 37 in the rod 26', thus fixing the block 24 against sliding on the rod.

As shown in Fig. 8, the dashpot cylinder 32 is closed at both ends by heads 35; and 39, and has slidably mounted therein between said heads a piston 44 which has piston rods 31 and 41 connected to opposite ends of its hub extensions 42. The piston 43 has a main part 43 forming a relatively large passage with branch passages 44 communicating with the chamber 45 at the right side of the piston. The hub 42 is counterbored on the left 1 5. Such .control valves are well known and readily obtainable on side of the piston 40 to form a guidewayfor a check of the seat near the right-hand end of the valve 45. v A relatively small bleed port 48 extends axially through the valve 45 and its eifective diameter is controlled by a needlevalve 49 that extends through an axial bore in the piston rod 31. The stem 5d of the needle valve 49 is adjustably connected to the rod 31 by threads 51, and has a knurled head-52 for adjusting the position of the needle. valve 47.

' The cylinder 32 is filled with oil. Its heads 38 and 39 are. provided with ports 53 and 54 respectively, for injecting and removing the liquid contents of the cylinder.

The port 53 is closed by plug 55 and the port 54 is closed by a valved oil cup 56.

The jack cylinder 29 has ports 57 and .58 in its heads for admitting and exhausting air to the chamber at opposite' sides of its piston 35. These ports are connected to a source of fluid under pressure preferably air, through a system of piping controlled'byfour valves actuated as a unit by electrical means, as illustrated in Figs. 4- and electromagnetically actuated four-way air the market, and are consequently sutiiciently represented for the purposes of this disclosure by these diagrams.

Fig. 4 shows the relation of the valves and air passages when the control switch is closed, and Fig. 5 shows the relation vthat exists when the control switch is open.

As shown in these diagrams, the jack cylinder 27 has its left-hand port 57 connected to pipe 59 which has one branch controlled by valve 60 leading to the air pressure source 61, and a second branch controlled by valve 60.1 leading to exhaust passage 62. The right-hand port 58 of cylinder 27, is similarly connected by pipe 63 and its branchesjthrough valve 64 to the air source 61, and through valve 64.1 to the exhaust main 62. When the button of switch 65' is in its closed'position, as indicated iniFig. 4, then valves 60 and 64.1 will be open and valves 60.1 and 64 will be closed, andthe direction of air flow will be as indicated by arrows in Fig. 4. When the control button of switch 65 is in its normal open position, as in Fig. 5 valves 60 and 64.1 will be closed and valves 60.1 and 64 will be open, and consequently air will be supplied under pressure to port 58 of jack 27 through will beexhausted through port 57 by pipe Figs. 3 and 9. The lever arms 66 are connected by-links 69 to a cross head 70 which is guided by parallel vertical rods 71, which are longitudinally slidable in the body of the'head 10, as shown in Fig. 2. The crosshead 70 has a hole-finding member 72 located in axial alignment with the spindle 73 of the milling head 10, and has a bore throughwhich the drill 74 may pass down into the work.

The switch 65, which is preferably a microswitch, is mounted in a housing 75 carried by the right-hand guide lever 66. The micro-switch is normally open. The handle bar'68 is hollow and has mounted therein an axially slid- ;able rod 76, vwhich is aligned with the button 65.1 of

the micro-switch, and is normally urged by compression spring 77 to a released position. -A control pin 78 extends crosswise through the hand bar and has a V-shaped cam notch 79 .in its side positioned to coact with the V shaped end 80 of the rod 76. The spring 77 tends to bring the pin 78 to a neutral position, as indicated in Fig. 9. When, however, the pin 78 is shifted longitudinally by finger pressure at either of its ends, the cam clips along the side of one of the adjacent levers 66, as'

indicated in Fig. 2, so as to be out of the way.

The operation of the device shown is as follows:

When in use, the motor that drives the spindle of the milling head 10 is in continuous operation and the drill is normally held in a raised position except while the switch 65 is held closed. The operator shifts the milling head over the work and for drilling seats the tip of the hole finder 72 into a hole inthe template and .thenpresses either end of the pin 78 toshiftthe bar 76 and close the switch 65. This. causes the fourway valve to be set, as shown in Fig. 4 to'supply airpressure to. the left-hand end of the cylinder 27, projecting the piston rod. 26 to the right as indicated by broken lines in Fig. 7. This'leaves the milling head 10 free to descend by gravity at a rate controlled by the dashpot 32. The weight ofthemilling head acting through bell crank lever 21 and the piston rod 31 forces the piston 40 to the left of Fig. 8. The flow of liquid through passage 48 sets the speed at which the milling head 10 can descend. This flow through the passage 48 is restricted by the needle 49, and thus can be adjusted by turning the needle forward or back by knob 52. l

When the operator releases the pin 78, spring 77 shifts bar 76 away from button 65.1 and the switch opens, cause ing the four-Way valve to'be set, as indicated in Fig. 5, to' admit air pressure at port 58 and exhaust air at port 57 of the jack cylinder 27,:lifting the milling head 10 so as to raise the drill 74 and hole finder 72 clear of the work.

Asshown in Fig. 8,. the dashpot 32 offers practically no resistance to the lifting of the milling head 10, since movement of piston 40 to the right causes the liquid to force the valve 45 away from its seat at the left-hand end of" the passage 43, and thus opensthat passage to the ports 47, permitting a rapid flow of liquid through the piston and consequent relatively free movement of the piston 40 to the'right.

The milling head 10 is provided with latching means for. locking it in an elevated position when'it is not in use.

This comprises a latch hook '82 pivoted at 83 on the cross head 70, and having a shoulder 84 adapted to be hooked over the stud 85 on a stationary part of the frame 11; The hook 82 is provided with a camming surface 86, which causes it to' ride into position for engagement with the lug 85; The latch hook 82 is normally urged by'a compression spring 87, into position for engagement of the shoulder 84with the lug 85, and is also provided with a trigger arm 88 which is in bell crank relation with the latch hook 82, and which extends forward where it can be easily reached by the operator to trip the latch when he isready to put the device to work.

An adjustable stop 891imits the normal upward move ment of the milling head by engaging the motor base mamber'18. This stop can be turned out of the way when the It is to be noted that the'control of the down strokev speed of the-millinghe'ad by the dashpot 32 avoids the breaking of the drill whenitcomes through the work. Without such control a drill; onpassing through'the work and meeting less resistance, tends to shoot through while the chip is too strong to be cut easily.

When the mechanism is out of service, the milling head will be held in an elevated position with the latch 82 engaged with the stud 85 of Fig. 3, and the parts of the actuating mechanism will be as indicated in Fig. 7, except that the slide 24 will be shifted a short distance to the left of the head 34 of the jack piston rod and the bell crank 21 will be tilted slightly further to the left. When the operator is ready to commence drilling operations, after having turned on the electric current and established pressure in the air line, he releases the latch 82 by means of the trigger 88, whereupon the milling head 10 falls a short distance by gravity until stopped by the engagement of the block 24 with the piston rod head 34, where it is held by air pressure at the right of the piston 34 of the jack 27, and the parts of the actuator will then be in the position shown in Fig. 7.

In the foregoing description and drawings, the invention is illustrated as applied to a drill. The actuator mechanism is the same for routing machines, except that the router does not require the hole finder 72 and the locations of the guide handles and the microswitch are changed to give greater visibility for guiding the router and milling head over the work.

Although but one specific embodiment of this invention is herein shown and described, it will be understood that numerous details of the construction shown may be altered or omitted without departing from the spirit of this invention as defined by the following claims.

I claim:

1. In a milling machine, a carrier frame mounted for movement in a horizontal plane, a milling head vertically slidable on said carrier frame, a fluid actuated jack on said frame having a reciprocating member, actuating means interposed between said member and said milling head for raising said milling head, said reciprocating member having a sliding connection with said actuating means and a shoulder for operatively engaging said actuating means upon movement in the lifting direction only, said reciproeating member slidably overrunning said actuating means upon movement in the opposite direction to release the same for gravitational descent of said milling head, a dashpot acting between said frame and head to retard the speed of descent of said head, a source of fluid under pressure, valve means operable for controlling admission of fluid from said source to said jack and the exhausting thereof to drive said reciprocating member selectively in opposite directions, a handle on said frame for guiding horizontal movement of said milling head, and manually controlled means on said handle operatively connected to said valve means for selecting the direction of movement of said reciprocating member.

2. The combination specified in claim 1, wherein the valve means is electromagentically actuated and the direction of movement of the reciprocating member is determined bythe opening and closing of the electric circuit by the manually controlled means on the frame handle.

3. In a milling machine, a carrier frame mounted for movement in a horizontal plane, a milling head vertically slidable on said carrier frame, a fluid actuated jack on said frame having a reciprocating member, actuating means interposed between said member and said milling head for raising said milling head upon movement in one direction, said actuating means comprising relatively overrunning parts adapted to release said milling head for solely gravitational descending movement upon a reverse movement of said reciprocating member, a dashpot acting between said frame and head to retard the speed of descent of said head, a source of fluid under pressure, and valve means for controlling admission of fluid from said source to said jack and the exhausting thereof to operate said reciprocating member selectively in opposite directions.

4. In a milling machine a carrier fiame mounted for movement in a horizontal plane, a milling head vertically slidable on said carrier frame, a fluid actuated jack on said frame having a reciprocating member, actuating means interposed between said member and said milling head for raising said milling head upon movement of said member in one direction, said actuating means comprising a rod connected to said reciprocating member, a traveler block in which said rod is longitudinally slidable and a shoulder on said rod positioned to engage said block for raising and to disengage said block for releasing said milling head, said millinghead being released to descend by gravity, a dashpot acting between said frame and head for retarding the speed of gravitational descent of said head, a source of fluid under pressure, and valve means for controlling admission of fluid from said source to said jack and the exhausting thereof to drive said reciprocating member selectively in opposite directions.

5. in a milling machine having a base, a vertically extending support column, and a horizontally extending carrier arm mounted on said support column, a milling head vertically slidable in ways mounted on the free end of said carrier arm and normally urged downwardly by gravity to an operating position, a fluid actuated double acting cylinder and piston mounted on said carrier arm adjacent its free end, a bell crank pivotally mounted on said carrier arm on a horizontal axis and having a link on one of its arms pivotally connected to said milling head, a rod on said piston having sliding connection with the other arm of said bell crank, a fixed shoulder on said rod for engaging said other bell crank arm to operate said bell crank for raising said milling head when both piston and rod are moved in one direction, said rod slidably overrunning said other bell crank arm when moved in the opposite direction and thereby releasing said milling head to descend by gravity, means for operating said cylinder and piston in opposite directions selectively, and means for regulating the rate of downward movement of said milling head.

6. In a milling machine having a base, a vertically extending support column and a carrier arm mounted on said support column for movement in a horizontal plane, a milling head vertically slidable in ways mounted on the free end of said carrier arm and normally urged downward by gravity to an operating position, a fluid actuated double acting cylinder and piston unit mounted on said carrier arm adjacent its free end and having apiston rod extending from the piston towards said milling head, a. bell crank pivotally mounted on said carrier arm on a horizontal axis adjacent said milling head and having a link on one of its arms pivotally connected to said milling head, said piston rod having a sliding connection with the other arm of said bell crank, a fixed shoulder on said piston rod for engaging said other bell crank arm to 0perate the same for raising said milling head when said piston is moved in one direction, said piston rod slidably overrunning said other bell crank arm when moved in the opposite direction and thereby releasing said milling head to descend by gravity, means for regulating the rate of downward movement of said milling head, a handle on said carrier arm for horizontally positioning said milling head, a valve having connections with said cylinder and operable for selectively delivering fluid pressure to either end of said cylinder for actuating said piston, and means on said handle operable by the operators hand while gripping said handle for operating said valve.

7. In a milling machine having a base, a vertically extending support column and a carrier arm mounted on said support column for movement in a horizontal plane, a milling head vertically slidable in ways mounted on the free end of said carrier arm and normally urged downward by gravity to an operating position, a fluid actuated double acting cylinder and piston unit mounted on said carrier arm adjacent its free end and having a piston rod extending from the piston towards said milling head,

7 a bell crank pivotally mounted on said carrier arm on a horizontal axis adjacent said milling head and having a link on one of its arms pivotally connected to said milling head, said piston rod having a sliding connection with the other arm of said bell crank, a fixed shoulder on said piston rod for engaging said other bell crank arm to operate the same for raising said milling head when said piston is moved in one direction, said piston rod slidably overrunning said other bell crank arm when moved in the opposite direction and thereby releasing said milling head to descend by gravity, meansfor regulating the rate of downward movement of said'millinghead, a handle on said carrier arm for horizontally positioning said milling head, an electromagnetically actuated valve having connection with said cylinder and operable for selectively delivering fluid pressure to either end of said cylinder, and r push button switch means on said handle having electrical connection with said valve for'operatingthe same;

References Cited in the file of this patent UNITED STATES PATENTS} 734,572 Koester July28, 1903 1,705,957 Braren Mar.- 19, 1929 1,962,524 Richards June 12, 1934 1,974,919 Harris et a1 Sept. 25,1934 1,983,438 Cushman Dec.,4,'1934 2,026,659 Siebenthaler Apr. '23, 1934 2,170,501

Klamp et al. Aug. 22, 1939

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