US2594520A

US2594520A - Two-hand press control device

Info

Publication number: US2594520A
Application number: US724797A
Authority: US
Inventors: Clarence C Tiedman
Original assignee: Individual
Current assignee: Individual
Priority date: 1947-01-28
Filing date: 1947-01-28
Publication date: 1952-04-29
Anticipated expiration: 1969-04-29

Description

April 9 1952 c. c. TIEDMAN 2,594,520

TWU-HMII PRESS CONTROL DEVICE Filed Jan. 28, 1947 3 Sheets-Sheet l C. C. TIEDMAN TWO-HAND PRESS CONTROLDEVICE April 29, 1952 3 Sheets-Sheet 2 Filed Jan. 28, 1947 IAZVENTOR.

BY @p (Zifornejs April 29, 1952 c c, TEDMAN 2,594,520

TWO-HAND PRESS common DEVICE Filed Jan. 28, 1947 3 Sheets-Sheet 3 Patented Apr. 29, 1952 UNITED STATES PATENT OFFICE TVVO-HAND PRESS CONTROL DEVICE Clarence C. Tiedman, Tonawanda, N. Y.

Application January 28, 1947 Serial No. 724,797

4 Claims.

This invention relates to improvements in means for safely starting the operation of a press or similar machine without endangering the hands of the operator.

Starting devices for presses have heretofore been constructed for the purpose of requiring both of the operators hands to start the operation of the press. Such means, however, have generally been so constructed that the operator was able to place a weight on one of the starting members or otherwise hold one of the startin members continuously in starting position, so that the press could be started with one hand, thus leaving the other hand free, with the resulting possibility of injury thereto.

One of the objects of this invention is to provide a press starting device of this kind which can only "be operated by having the operator actuate both starting members with both of his hands, and then release both starting members before the press can again be started. Another object is to provide starting means or this type in which both of the hand-operated starting members must be moved into two different positions for each start of the press.

A further object is to provide a starting means including a storage device for storing power durme one position of the hand-operated members and for discharging thestored power to the pressstarting mechanism when the hand-operated members are in another position.

A further object is to provide a pair of handoperated electrical switches which, in One of their positions, close a circuit to a condenser for charging the same, and which when moved by the hands into another position close another circuit for discharging the condenser to effect actuation of the starting mechanism.

Another object is to provide a device which is constructed to effect the actuation of the starting mechanism of a press or similar machine from the electrical discharge of a condenser.

Other objects and advantages of this invention will appear from the following description and claims.

In the accompanying drawings:

Fig .1 :is a fragmentary, front elevation or a punch press provided with starting means embodying this invention.

2 is a diagrammatic View of the electrical connections for actuating the starting mechanism of the press.

Fig. 3 is a fragmentary, sectional elevation of a starting mechanism operated by compressed air and which may be actuated by means of the improvements embodyingthis invention.

Fig. 4 is a fragmentary, sectional elevation thereof, on line 4-4, Fig. 3.

Fig. 5 is a sectional plan view thereof, on line 55, Fig. '3.

Fig. 6 is a fragmentary, sectional elevation of an electrically-operated mechanism for starting the press.

Fig. '7 is an elevation of an air-operated starting mechanism of modified construction which may be actuated by the press starting means em.- bodying this invention.

Fig. 8 is a fragmentary, sectional elevation thereof, on an enlarged scale.

My improvements may be applied to the actuation of any intermittently operating press or other machine, and in Fig. 1, I have illustrated by way of example, a punch press to which my improvements may be applied. The word press as hereinafter used is intended to apply to any type of press or similar machine. The press shown in the drawings has a bed or base 10 and a die H mounted thereon. i l represents the ram of the press on which a punch or complementary die 14 is mounted to cooperate with the die II. The ram may be actuated in any suitable manner, for example, by means of an eccentric or crank actuating a pitman i5, 18 represents the flywheel of the press which may be driven by any suitable motor or other power means (not shown) through the medium of a clutch I1 interposed between the flywheel l6 and the crank or eccentric which actuates the pitman and this clutch is actuated by means of a clutch rod I8 which is movable upwardly to engage the clutch and downwardly to disengage the same. The actuating means for the clutch rod may be confined within a housing 19 mounted on a press. All the parts thus far described have heretofore been used in connection with presses, and of themselves, do not constitute a part of this invention.

My invention deals particularly with means for controlling the mechanism for starting the operation of the press, which in the particular construction shown in Fig. -1 is arranged within the housing l9, and this controlling mechanism is so constructed that the operation of the press can only be effected if the operator uses both hands to actuatetwo diifierent members, so that it will be impossible to operate the press while the operator has his hands in positions in which they might be injured. For this purpose, a pair of hand-operated

control members

20 and 21 are provided on the press and spaced apart far enough so that the operator must use both hands to actuate these control members. In the particular embodiment of the invention illustrated by way of example, these two members are in the form of switches as shown more particularly in Fig. 2, each switch havinga conducting-memher 22. The hand-operated members are preferably normally held in their upper positions by. any suitable means such for example as springs (not shown), which urge the control members into their upper positions in Figs. 1 and 2.

I also provide a storage device which is capable of storing only enough energy to provide for one actuation of the press, the storage device being charged only when both of the control members are in their normal positions which they occupy when released by the operator. For example, an electrical condenser 25 may be employed for this purpose and the control members 20 and 2| are so connected with the condenser that when the control members are in their upper positions in the construction shown, a circuit will be completed by means of which the condenser will be charged, and when these members are in their lower positions, another circuit will be completed by means of which the electrical charge in the condenser will be discharged to efiect the starting of the press. For this purpose, electric power from any suitable source may be received from a pair of conductors 26 and 2?. If alternating current is supplied to these lines, suitable rectifying means are provided for char ing the condenser, those shown by way of example being arranged within the usual tube 28. The conductors 26 and 21 are connected to the opposite terminals of a filament 29 in the tube 28 and a branch conductor 30 connects conductor 21 to one of the terminals of the condenser 25. The other conductor 26 is connected to a pair of cathodes 32 within the tube 26. The anode plates 33 are connected to a conductor 34 which leads to the two switch or control members 20 and 2|, the circuit including conductor 3 being broken at each switch member and completed only when both switch members are in the upper positions as shown in Fig. 2, in which case, direct current passes through the conductor 3 and the two switch members 20 and 2! to a conductor 35 leading to the other terminal of the condenser, thus completing a circuit for charging the condenser. It will be noted that the circuit to the condenser for charging the same is only closed if both of the switch members 20 and 2| are in their upper or normal positions at the same time.

The other or discharge circuit includes another conductor 31 which has two gaps or breaks therein which are closed when the switches or

control members

20 and 21 are moved into lower positions by the hands of the operator. This conductor leads to one terminal of the coil of a relay 38, the other terminal being connected by means of conductor 39 to the negative terminals of the condenser 25. It will, consequently, be

' apparent that the circuit including the conductor 3'! can only be closed if both of the

switch members

20 and 21 are moved into their lower position. v

The relay 38 closes a switch 46 in a circuit including a pair of

conductors

42 and 43 receiving power from any suitable source and leading to the opposite terminals of the solenoid 54, this relay circuit being necessary because of the small power developed from the discharge of the condensers. The core of the solenoid 44 may either actuate the clutch rod l8 directly or through the medium of some other power operated means. For example in Fig. 6, the solenoid 44 has its core 45 connected by means of a link 46 to a lever 48 pivoted at 49 on a housing 50. The clutch rod l8 extends into the housing and has a shouldered portion formed by a projection or enlargement 52 provided on the lower end thereof with which the outer end of the lever may engage. This lever has a dog or latch 53 mounted on the end thereof in position to engage the enlargement 52 of the clutch rod when the lever 48 is swung downwardly by the core of the solenoid A l. The latch 53 is pivoted at 54 on the lever 43 and the latch engages a stop when in the position shown in Fig. 6 to prevent further upward movement of the outer end thereof and a spring 55 yieldingly holds the latch in this position. As the core 45 approaches the end of its downward movement, the end of the latch 53 will swing out of engagement with the enlargement 52 of the clutch rod, and thus permit this rod to be moved upwardly by the usual clutch rod spring (not shown). Consequently, even if the solenoid 44 should remain energized for a period longer than that required for an operation of the press, the clutch rod [8 will be released promptly upon the completion of the downward swinging of the lever 48 so that only a single operation of the press will be assured. When the solenoid is deenergized, the core 45 is returned upwardly by any suitable means, such as a spring 56, so that the lever 48 will swing upwardly to place the latch 53 into a position to engage the upper surface or shoulder of the enlargement 52 of the clutch actuating rod, so that the mechanism is then ready for another operation. During this movement of the lever, the latch will swing on its pivot to clear the enlargement 52 and will be restored to the position shown in Fig. 6 by the spring 55.

My improved controlling mechanism may also start a press through the medium of a fluid under pressure, such as compressed air or other gas. In the particular construction shown in Figs. 3 to 5, the solenoid M is mounted in the housing It. The lower end of the core 45 of the solenoid engages an end of a valve actuating lever or arm 62. The connection between the solenoid core and the lever or arm may be made by means of a U-shaped link or clevis 63 mounted on the end of the core and extending about the end of the arm 62. 64 represents a stop to limit the extent to which the solenoid and the clevis 63 may move downwardly.

The arm 62 has a post 65 rigidly secured thereto, the upper end of which is provided with a substantially hemispherical part 66, which seats in a partly spherical bearing in the lower end of a thimble or sleeve 61 secured to a valve housing 19. A hollow tubular stem 68 is slidably arranged in a partition wall 69 arranged in the housing 16 and suitable packing is provided about the stem 68 to prevent leakage about'the stem. The lower end of the tubular stem has a flange or head ll secured thereto against which a spring 72 bears to urge the tubular valve stem and head H into engagement with the enlargement 66 of the post 65. The valve housing 16 is also provided with a .valve 14 which controls the passage connecting two chambers 75 and 16. The chamber 15 is connected by means of a duct 11, leading from a source of compressed air or other gas and the chamber 16 is connected with a conduit 18 leading to a cylinder 39 which is hereinafter more fully described.

It will be noted that the swinging of the arm 62 causes the enlargement or head 66 of the post 65 to swing or pivot on its bearing in the sleeve 67. When in the position shown in Fig. 4, the upper face of the enlargement, 66 is parallel'to the head or enlargement H of the tubular stem 88, and consequently, the spring 12 holds this tubular stem in its lowest position. When the arm 52 swings, an edge portion of the enlarged head 60 of the post 65 will tilt upwardly, thus moving the head or flange 'II and the hollow stem 88 upwardly so that the upper open end of the stem engages a packing disk 19 secured to the lower face of thevalve "I4, thus closing the upper end of the tubular stem and also moving the valve I4 upwardlyirom its seat, thus permitting air from the "duct TI to pass to the duct I8 to the cylinder 80. When the solenoid is de-energized so that its core moves downwardly into the positlon shown in Fig. 3, the enlargement B6 or the post 65 again assumes the position shown in Figs. 3 and 4 and permits the tubular stem 68 to move downwardly, thus restoring the valve I4 to its seat. Upon further downward movement by the action of the spring 12, the upper end of the d tubular stem 68 will disengage the packing disk and thus permit air to flow into the interior of the tubular stem, from where it is discharged through holes 82 in the stem and thence through holes '83 in the sleeve or thimble 61, so that the exhaust is discharged to the atmosphere. Any other suitable valve for controlling the flow of fluid under pressure to and from the cylinder 8?, may be employed, if desired.

The cylinder 80 has a piston or plunger 84 therein, see Fig. 3, which is urged into its upper position in the cylinder by means of a spring '85. The piston is connected to a piston rod 88 and has an Inverted U"-shaped lower fitting, the legs 01 of which straddle and are suitably connected to a lever 88 which may be similar in construction to the lever 48 described in connection with Fig. 6. The lever 88 is pivoted at one end thereof at 89 to the housing I9, and has a latch 90 at the other en'd'thereof which is yieldingly held, for example,

by a spring 92 in the position shown in Fig. 3. The end of the latch may engage an enlargement 93 of a clutch actuating rod I0. This rod is normally held .in its upper or clutch disengaging position by means of a spring 95.

The operation of this device will be obvious, since when the solenoid core is drawn upwardly due to current supplied to the solenoid 44 by closing the relay switch 40, the arm 62 will swing to move the valve stem into its upper position causing the valve 14 to be raised, and thus permitting air from the inlet pipe TI to pass through the pipe I8 to the upper portion of the cylinder 00, thus forcing the piston 04 downwardly against the action of the spring 85, causing the lever 88 to be swung downwardly. The latch 90 of this lever carries the clutch actuating rod is downwardly until the end of the clutch moves out of engagement with the enlargement 93 of the clutch actuating rod I8 as shown in broken lines in Fig. 3. During this downward movement of the rod I8, the clutch of the press is movedinto engagement, thus causing the crank shaft of the press to make one revolution. Before this revolution is completed, the clutch actuating rod I8 has been again moved into its upper position by the spring 95, thus preventing a second operation of the press until the clutch rod I8 is again pulled down. As soon as the solenoid 44 is de-energized and the core 45 thereof .re-

turned to its upper position by suitable yielding means such as a spring (not shown), the supply of air "to the "cylinder is interrupted and air is discharged from the cylinder through the conduit I0 and through the hollow stem 68, the piston 84 and the lever 88 connected therewith are urged upwardly by the spring 85. As the clutch passes the enlargement 93 on the end of the clutch actuating rod I8, the latch swings about its pivot 91 and after the end of the latch has passed the enlargement 93, the latch is returned to a position above the enlargement 93, whereupon the device is ready for another operation.

A device of modified construction for cooperating with my controlling mechanism is shown in Figs. '7 and 8, in which iluid pressure is also employed. In these figures, I00 represents the solenoid similar to the solenoid 44 and having a core I0'I which engages an arm or lever I02 for ac tuating a valve I03 which may be similar in construction with "the valve shown in Fig. 4. Fluid under pressure is discharged from the valve I03 through a duct I04 to the upper end of a cylinder I05 arranged in a housing 106. A piston I01 arranged in the cylinder I05 has a tubular or hollow piston rod I08 connected therewith, the piston rod being releasably connected with an enlarged portion I09 of a clutch actuating rod H0, which corresponds to the rod I8 of Figs. 1, 3 and '6. A spring I I I urges the piston into its upper position in the cylinder I05, the lower end of this spring engaging a flange I I-2 of a bushing H4 adjustably secured in the lower part of the housing I00, and the lower end of the valve actuating rod I09 is guided for movement in the bushing H4. The bushing H4 is provided with a liner or bearing H5 in which the lower end of the clutch actuating rod bears.

Suitable means are also provided for releasing the piston rod I08 from the clutch actuating rod at the end of its clutch actuating movement to permit the clutch actuating rod to be quickly returned to its upper position to prevent repeating of the press, i. e. moving through another cycle of operation. In the construction shown for this purpose, the large portion I00 of the clutch actuating rod is provided with a circumferential groove I20 adapted to receive a plurality of balls I2I, and the tubular piston rod I08 is provided with holes I22 therein in which the balls I2I are loosely arranged. The movement of the balls into and out of the groove is controlled by a cap member I23 which is slidably mounted on the hollow piston rod I08, and which has a downwardly and outwardly flaring inner surface or here. Consequently, when the cap member is in its lower position, as shown in full lines in Fig. 8, this flaring surface moves the balls into the groove so that the balls form a rigid connection between the tubular piston rod I08 and the clutch actuating rod IIO. As the piston moves downwardly, the lower end of the cap member I23 will engage the flange I12 of the bushing II4 while the tubular piston rod I08 moves down toward the flange I I2, and this relative movement enables the balls I2I to move outwardly out of the groove I20 into the wider portion of the irusto-conical bore in the cap member I23, thus uncoupling the hollow piston rod I08 from the clutch actuating 'rod H0, :as shown in broken lines in Fig. 8. This latter rod is engaged by suitable yielding means, such as a spring II8 to urge the same rapidly upwardly, when disengaged from the tubular piston rod I08, thus returning the clutch actuating rod to its upper and clutch disengaging position in ample time to prevent a second operation of the press.

The solenoid I00 and the housing I 08 :may be suitably mounted-on a press in any desiredmam ner, for example, by means of a bracket 122, Fig. 7, which may be'suitably secured to the press. The bracket preferably is provided with a stop 124" against which the lower end of the spring H8 may bear.

I In the drawings, I have illustrated only a pair of control members 20 and 2| for use on a press requiring only a single operator, it will be obvious that on larger presses requiring a number of operators, a plurality of pairs of control members or switches may be provided, one pair for each operator, and these switch members would be arranged in the conductors 34 and 31, so that circuits through these conductors would be completed only when all of the switch or control members are moved into positions for charging the storage device, or for discharging the same.

-,I claim as my invention:

- 1. In means for controlling mechanism for starting the operation of a power-actuated plunger of a press having a clutch and a rod for actuating said clutch and which is yieldingly urged into clutch disengaging position, that improvement which includes an electrical condenser, a plurality of hand-operated switches having movable members yieldingly urged into normal positions, a circuit leading from a source of power to said condenser 'for charging the same and which circuit is completed only when the movable members of all of said switches are intheir normal positions, another circuit through which discharge current from said condenser flows only when the movable members of all of said switches are moved from their normal positions into another position, a relay in said other circuit for closing a switch, a'third circuit including said switch and a solenoid having a core connected with said clutch rod for moving'said clutch rod into clutch-engaging position, and means for disconnecting said solenoid core from said clutch rod after said clutch rod has been moved into clutch-engaging position and for again connecting said solenoid core with said clutch rod when said solenoid core is moved into a position to again repeat the operation.

2; In means for controlling mechanism for starting the operation of a power-actuated plunger of a press having a clutch and a rod for actuating said clutch and which is yieldingly urged into clutch disengaging position, that improvement which includes an electrical condenser, a plurality of hand-operated switches having movable members yieldingly urged into normal positions, a circuit leading from a source of power to said condenser for charging the same and'which circuit is completed only when the movable members of all of said switches are in their normal positions, another circuit through which discharge current from said condenser flows only when the movable members of all of said switches are moved from their normal positions into another position, a relay in said other circuit for closing a switch, a third circuit in cluding said switch and a solenoid having a core, a cylinder containing a piston connected with said clutch rod for moving the same into its clutch-engaging position, a valve for controlling the flow of fluid under pressure to said cylinder, and means connecting said solenoid core to said valve for actuating the same.

3. Means for controlling mechanism for starting the operation of a power actuated plunger of a press, said means including a condenser, a charging circuit for supplying electric power to said condenser for charging the same, a discharge circuit including said condenser, relay means actuated by current discharged from said condenser through said discharge circuit for starting the operation of said plunger, and a series of switches each including terminals arranged in series in said charging circuit and other terminals arranged in series in said discharging circuit; each switch including a movable switch member, means for yieldingly urging said movable member into a position to contact said terminals of said charging circuit to complete the same, said movable members of said switches being movable manually against said yielding means to connect said terminals of said discharge circuit to complete the same, a pair of said switches being provided for each operator of the press, whereby said charging circuit is closed only when all of said switches are released by the operator or operators of said press and said discharge circuit is closed only when all-of said movable members are moved by the operator or operators against the action of said yielding means.

4. Electrical means for controlling mechanism for starting the operation of a power operated plunger of a press, said means including a condenser, a charging circuit connecting said condenser with a source of power for charging said condenser, a discharge circuit including said condenser, a solenoid also included in said discharge circuit, a solenoid-actuated circuit for starting the operation of said plunger, a pair of switch members each including terminals arranged in series with said charging circuit and other terminals arranged in series with said dis charge circuit, each switch including a movable switch member capable of engaging either set of terminals means for biasing said movable switch I member into position to engagesaid terminals of said charging circuit, said switches being spaced apart sufficiently so that both hands of the operator are required to actuate both switches of said pair, said movable switch members when urged againstsaidbiasing means be ing movable into engagement with said terminals of said discharge circuit, whereby both of said movable members must be released by the operator to efiect charging of said condenser and must be moved by the operator against said biasing means to simultaneously engage said terminals of said discharge circuit.

CLARENCE o. TIEDMAN.

REFERENCES circle The following references are of record in the file of this patent:

UNITED STATES PATENTS Snyder Sept. 23, 1947