US3006305A

US3006305A - Means for feeding work-pieces to power-presses and like machines

Info

Publication number: US3006305A
Application number: US368435A
Authority: US
Inventors: Evans Frederick Arthur
Original assignee: Individual
Current assignee: Individual
Priority date: 1952-02-23
Filing date: 1953-07-16
Publication date: 1961-10-31
Anticipated expiration: 1978-10-31
Also published as: GB733347A

Description

Oct. 31, 1961 F. A. EVANS 3,005,305

MEANS FOR FEEDING WORK-PIECES T0 POWER-PRESSES AND LIKE MACHINES 5 Sheets-Sheet 1 Filed July 16, 1953 W Mm Ema MAM M R A w m n 7 1H mm mm Oct. 31, 1961 F. A. EVANS 3,006,305

MEANS FOR FEEDING WORK-PIECES TO POWER-PRESSES AND LIKE MACHINES Filed July 16, 1953 5 Sheets-Sheet 2 PM /W so 7 [v van/r01? 5205mm 411mm 12/ us Oct. 31, 1961 F. A. EVANS MEANS FOR FEEDING WORK-PIECES TO POWER-PRESSES AND LIKE MACHINES 5 Sheets-Sheet 3 Filed July 16, 1953 MEANS FOR FEEDING W E ANS ORK-PIECES TO POWER-PRESSES AND LIKE MACHINES Filed July 16, 1953 5 Sheets-Sheet 4 fies-15mm 4127/11/12 5M6 Oct. 31, 1961 F. A. EVANS 3,006,305

MEANS FOR FEEDING WORK-PIECES TO POWER-PRESSES AND LIKE MACHINES Filed July 16, 1953 5 Sheets-Sheet 5 INVENTQR V flqsoenrcx AR MR [VA/vs MAGZSW' UnitedrStates Patent Office 3,006,305 Patented Oct. 31, 1961 3,006,305 NIEANS FOR FEEDING WORK-PIECES T POWER-PRESSES AND LIKE MACHINES Frederick Arthur Evans, 76-78 Hunters Vale, Birmingham, England Filed July 16, 1953, Ser. No. 368,435 1 Claim. (Cl. 113-38) This invention relates to new or improved means for feeding work-pieces to power-presses and like machines.

In the usual type of power-press a continuously-driven flywheel is adapted to be coupled by a manually operated clutch to a crankshaft which actuates a vertically movable ram or plunger carrying an upper tool or die which co-operates with a stationary bottom tool or die. Workpieces or components are fed to the press by an operator who picks up a component, places it on or in the bottom tool or die, actuates a pedal or lever for setting the press in motion to make an operative stroke, and then removes the finished work-piece. The clutch is usually a key clutch so designed that when the pedal or lever is actuatedto engage the clutch and then is released the press only makes a single operative stroke, the crankshaft coming to rest at top dead center and remaining stationary until the clutch pedal or lever is again actuated.

Means are known for feeding work-pieces automatically to a power-press, such means comprising an oscillating or reciprocating arm actuated from the crankshaft of the press and having at its free end a device for picking up and releasing a component, the component being picked up at a point remote from the tools and being transferred to the tools by the angular movement of the arm.

Automatic feeding means of that type are limited in their application as they require a certain minimum clearance or daylight between the tools when the ram i at the top of its stroke in order to allow time for the arm and gripping device to move clear of the tools on the working stroke. Further, as the feeding mechanism operates on every stroke of the press it is usually necessary to reduce the speed of the press in order to allow the operator time to keep up the supply of components and to limit the effect of inertia on the reciprocating parts of the feeding mechanism. Any reduction in the speed of rotation of the flywheel reduces its momentum and hence the energy applied to the component by the moving tool or die.

According to my invention automatic feeding mechanism for power-presses comprises interconnected means driven independently of but synchronised with the operation of the press for performing in sequence a number of operations including picking up a component at a point remote from the tools and transferring it to the tools, the last operation being the engagement of a clutch which sets the press in motion to make a single operative stroke.

With this arrangement the speed of operation of the feeding mechanism is independent of the speed of the flywheel of the press which can be run at its normal Working speed While the feeding mechanism can be operated at any convenient speed.

The feeding mechanism may be operated intermittently by a fluid pressure cylinder in synchronism with the operation of the press, all the movements of the feeding mechanism taking place while the ram of the press is stationary and. the clutch being engaged as or after the feeding mechanism comes to rest. Alternatively the clutch may be engaged after the component has been fed to the tools and while the feeding mechanism is returning to its normal rest position so that the interval between working strokes of the press is reduced.

Preferably, however, the feeding mechanism is driven by a continuously running motor and the mechanism controls the setting in motion of the press, means being pro-- vided for preventing the press from being set in motion while any part of the feeding mechanism is adjacent to the press tools or dies.

In either case the arrangement is such that the mechanism can be used on any press so long as the clearance between the tools is sufficient to admit the means for gripping the component. 7

The complete feeding mechanism is preferably designed as a unit or set which can readily be fitted to existing presses, a fluid-pressure cylinder being provided for operating the clutch of the press and being controlled by the feeding mechanism.

The feeding mechanism can be arranged in various ways.

One practical embodiment of my invention is illustrated by Way of example in the accompanying drawings in which:

FIGURE 1 is a side elevation of the feeding mechamsm.

FIGURE 2 is a side elevation of the valves controlled by cams on the crankshaft of the press.

FIGURE 3 is a plan of the feeding mechanism.

FIGURE 4 is a side elevation on a larger scale of the driving part of the mechanism.

FIGURE 5 is a plan on a larger scale of the driving part of the mechanism.

FIGURE 6 is a diagram of the various pneumatic valves and their actuating means.

The feeding mechanism illustrated comprises four units, a driving and operating unit adapted to be bolted to the table of a press, a valve unit adapted to be mounted adjacent to the end of the crankshaft of the press, a rotary table or other feed adapted to be mounted on the front of the table of the press, and a pneumatic cylinder for actuating the press clutch pedal. All these are designed so that they can be readily fitted to any type of press.

The main unit incorporating the drive and the recip rocau'ng feeding means is carried by a rigid frame or base member 10 which is adapted to be bolted to the table of a press. The mechanism is driven by an electric motor 11 coupled by a V belt 12 to the input shaft of worm or other reduction gearing in a gear-box 13. The V pulleys 14 on the motor and input shaft of the gear-box are preferably of the known variable type in which one flange of each pulley is axially movable on its shaft and the movable flanges are coupled to a common control lever or the like by which the movable flange of one pulley is moved towards the fixed flange while the movable flange of the other pulley is moved away from the fixed flange to vary the gear ratio of the drive. This is desirable to allow the speed at which the feeding mechanism is driven to be adjusted to suit the speed of the press. A friction clutch is arranged between the input shaft of the gearbox. and the pulley on that shaft and is controlled by a lever at the front of the press so that the feeding mechanism can be stopped without stopping. the motor and can be inched or moved through small distances when it is being set.

The output shaft of the gear-box, which is horizontal, and extends through the gear-box carries on its inner end a disc 15 on which is mounted a crank-pin 16 coupled by a link 17 to a crank-pin 18 on a disc 19 which is angularly movable about a fixed horizontal axis, the arrangement being such that the continuous rotation of the disc 15 oscillates the disc 19 about its axis through a predetermined angle.

The disc '19 carries a projecting eccentric pin 101 connected through a universal spring-loaded coupling 102 to one end of a substantially horizontal rod 20. The other end of the rod is pivotally connected by a fork 103 to a head 104 on a feeding arm 22 which is angularly movable about a vertical axis 21 on a block 105. Thus, as the disc 19 oscillates about its axis it produces reciprocating angular movement of the arm 22 about its axis 21 between adjustable stops 106 mounted on the block 105.

The block 105 is mounted for angular movement about a substantially horizontal axis, and a lever 23 pivotally mounted to rock about a fixed horizontal axis 107 is adapted at one end to be engaged by angularly spaced cams 24 on the disc 19 and at the other end carries a tappet 108 engaging the block 105 at a point spaced from its axis.

The angular positions of the cams 24 are such that at the end of each of the angular movements of the arm 22 about its axis 21 the block 105 is rocked by the lever 23 to produce a short vertical movement of the free end of the arm 22, the return movement of the block being effected by a spring.

The arm 22 has on its free end two-co-operating gripping members or jaws 25 pivoted at 26 on a head carried by the arm. The rear ends of the jaws are adapted to be engaged by a cone or Wedge 27 which is movable axially to cause the jaws to grip or release a Work-piece by an air cylinder 28 which is incorporated in the arm and to which compressed air is fed by a flexible pipe connected to a union 29.

Work-pieces or components are fed by the operator on to a rotary table 30 mounted on the front of the press and adapted to be rotated step-by-step by a pneumatic cylinder 30 to bring the components around into a position from which they are picked up by the jaws 25 on the arm 22 for transfer to the press tools.

The 'clutch pedal 31 of the press is actuated by a pneumatic cylinder 32 mounted on an adjustable bracket 33 on the frame of the press at a suitable point.

The sequence of operations of the mechanism is controlled by valves actuated by cams on the disc 19, on the crankshaft 34 of the press, and on a disc 15 on the outer end of the output shaft of the gear-box.

Compressed air from a main supply is brought to a T junction 35 from' which one branch is taken through a reducing valve 36 and an air line lubricator 37 to a junction 38, and another branch is taken to a second T junction 39. One branch from that junction is taken to a pressure gauge 40 and the other to a pair of

valves

41, 42 mounted on a bracket 43 and actuated by

cams

44, 45 on the crankshaft 34 of the press. One branch from the junction 38 is taken to a valve 46 which is mounted on a bracket 47 and is held closed when the crankshaft is at rest at top dead center by a cam 48 on the crankshaft, this valve being connected to a chamber 49 on one side of a diaphragm coupled to a valve 50. This valve is also actuated by a cam 51 on the disc 15 on the front end of the output shaft of the gear-box. V

A third branch from the junction 38 is taken through a T junction 52 to a valve 53 actuated by a cam 54 on the disc 19. The junction 52 is also connected through a restrictor 55 to a valve 56 actuated by a cam 57 on the 'disc 15; i i

,The valves 41 and 42-supply compressed air to nozzles 41' and 42' located at suitable points for blowing away swarf and for removing the finished component from the die. The valve 46 controls the supply of air to the diaphragm in the chamber 49 which is coupled to the valve 50 controlling the supply of compressed air to the cylinder 32 which depresses the pedal 31 to engage the clutch and set the press in motion. The clutch is engaged when the valve 50 is opened by the cam 51. As soon as the press starts the cam 48 on the crankshaft which normally holds the valve 46 closed when the press is stationary passes out of engagement with the valve so that the valve opens and allows air to pass to the chamber 49 to actuate the diaphragm which closes the valve 50 and de-energises the clutch cylinder 32 so that the press only makes a single working stroke. The valve 53 which is actuated by the cam 54 on the disc 19 supplies comprwsed air to the cylinder 28 which actuates the grippers 25 to pick up and release the component, and the valve 56 which is actuated by the cam 57 on the disc 15 supplies compressed air to the cylinder 30 which rotates the feeding table step-by-step.

Normally the feeding mechanism is continuously driven and the sequence of operation is as follows: a

The arm 22 is swung outwardly to bring the fingers 25 over a component on the table 30 and is rocked downwardly to bring the fingers into the plane of the component. The valve 53 is opened to energise the cylinder 28 to close the grippers on to the component and the arm is rocked up to lift the component and is swung around inwardly to bring the component into position over the bottom tool. The arm is rocked down to lay the component in the tool and the cylinder 28 is de-energised to release the component. The arm is rocked up again to lift the grippers clear of the tool and is swung around outwardly again towards the table 30. While the arm is making that movement and after it is clear of the tools the valve 50 is opened by the cam and momentarily energises the cylinder 32 which depresses the pedal 31 to engage the clutch of the press and set the press in motion. As soon as the crankshaft of the press starts to rotate the valve 46 opens and admits air to the chamber 49, and the diaphragm in that chamber closes the valve 50 and de-energises the cylinder 32 so that the pedal 31 is released and the press only makes a single working stroke. As the ram of the press moves upwardly the

valves

41 and 42 are opened to supply air to the nozzles 41' and 42' to blow away swarf and eject the finished component. Meanwhile the valve 56 has been opened by the cam 57 to supply air to the cylinder 60 to rotate the table 30 through one step and bring another component into position for engagement by the grippers.

It will be appreciated that the rotary table 30 is only shown as an example of one type of feeding mechanism and that a magazine'or other type of feed may be used according to the shape and dimensions of the component.

A fixed guard to comply with safety regulations can readily be arranged between the point at which the components are picked up and the point where the operator puts them on to the rotary table or into the magazine. This guard may conveniently be made of transparent plastic so that the operator can watch the movements of the feeding mechanism and of the press tools but cannot put his hands anywhere near the tools.

The clutch in the drive between the motor 11 and the feeding mechanism allows the feeding mechanism to be started and stopped without stopping the motor so that a vacuum or other pump which has to be continuously driven may be coupled directly to the motor. It may for example be mounted below the motor and be driven by an extension of the motor shaft.

' p I claim:

Automatic mechanism for feeding individual compo 'nents to a power press incorporating cooperating tools for performing an operation on a component, a crankshaft for actuating one of said tools, and a clutch for coupling said crankshaft to a power driving means to make a single operative stroke, comprising an angularly reciprocating arm, means on the end of the arm for picking up a component at a point remote from the tools in one angular position of the arm and for transferring it to the tools and releasing it in another angular posi tion of the arm, power driven mechanism independent of the press for reciprocating said arm, a fluid pressure actuator for said press clutch, a valve controlling the admission of fluid to said actuator, means on a moving part of said power driven mechanism for opening said valve to energize the actuator and engage said clutch at a predetermined point in the cycle of movement of the reciprocating arm, and means actuated by the crankshaft of the press for closing said valve when the crankshaft is set in motion, the means for opening said valve comprising a cam on a rotating part of said power driven mechanism, the means for closing said valve comprising a diaphragm actuated by pressure fluid controlled by a normally closed valve which is opened by a cam on a part of the press when the press is set in motion.

References {Zited in the file of this patent UNITED STATES PATENTS 2,012,423 Ferris Aug. 27, 1935 2,049,915 Lewis Aug. 4, 1936 2,133,161 Colbert Oct. 11, 1938 2,183,287 Candee Dec. 12, 1939 2,317,440 Cannon Apr. 27, 1943 2,600,667 Mason June 17, 1952 2,623,274 Henchert Dec. 30, 1952 2,794,523 Cortelli June 4, 1957 FOREIGN PATENTS 597,636 Great Britain Ian. 30, 1948