US2642973A

US2642973A - Pressing and like machine

Info

Publication number: US2642973A
Application number: US782989A
Authority: US
Inventors: Chmelar Vaclav
Original assignee: BATA NARODNI PODNIK
Current assignee: BATA NARODNI PODNIK
Priority date: 1946-11-16
Filing date: 1947-10-30
Publication date: 1953-06-23
Anticipated expiration: 1970-06-23

Description

June 23, 1953 v. cHMELAx 2,642,973

PRESSING'AND LIKE MACHINE Filed oct. so, 1947 l JNVENTOR,

'Vaclav Chmefas'f atentec .un v23, 1953 UNITED STATES PATENT OFFICE PRESSING AND LIKE MACHINEv Vclav Chmela', Zlin, Czechoslovakia, assigner to Bata narodni podnik, Zlin, Czechoslovakia Application october 3o,'1947, serial No. 782,989 In Czechoslovakia November 16, 1946 7 Claims. 1

The present invention relates to a pressing machine, such as a shoe-sole or inner-sole pressing machine, with a protective device which prevents injury to the workman if he forgets to remove his hands at the right time from the working position between the press moulds.

In working with pressing, stamping, punching and like machines it frequently happens that the workman starts the machine running before withdrawing his hands from the working position, which results in serious injuries to the hands, and often completely incapacitates the workman. Quite a number of protective devices have therefore already been suggested, which are designed to prevent such accidents, but these have frequently met with an unfriendly reception from the workmen, as they either proved a hindrance to the work or were not altogether reliable. Other devices, which were based on the principle of a wedge penetrating between the press moulds and of the machine stopping at the moment of danger, usually resulted in the destruction of the moulds or else of the machine frame upon the occurrence of the impact between the movable mould and the xed mould.

Now the object of the present invention is to provide an arrangement which will quite reliably prevent an accident to the worker between the press moulds, while at the same time all possibility of injury to the moulds or any other parts of the machine is precluded, and the workman is neither hindered nor checked in the manipulation of the article that is being pressed.

According to the present invention the mould member that is normally stationary is mounted upon a displaceable cylinder, which rests, through the medium of a cushion of luid, upon a xed piston, the cushion of fluid being closed byV a valve which is controlled by a protective hoop that covers the working position. In the event of the protective hoop being prevented by any obstruction, such as the workmans hand, from covering the working position, the valve remains open,'the cushion of iluid remains without pressure, and the pressing operation is not initiated at all, since the normally stationary mould is raised along with the displaceable mould, remaining at a sufcient distance from the latter.

Further advantages and characteristics of the present invention will appear from the following description and from the drawings of one constructional example, in which:

Figure 1 is a diagrammatic view in sectional elevation of a pressing appliance in a position before the beginning of the work; and

2 Figure 2 shows a similar section through the same apparatus in the working position, when the risk of an accident has arisen.

The working parts of the pressing machine, for instance of the machine illustrated for pressing shoe soles, consist of a lower mould I, which is arranged on a work table 2, which executes the usual working stroke up and down. An upper mould 3 is secured to a cylinder 4, which is slidably arranged upon a hollow piston 5, which is clamped in the machine frame 8, which at the same time also determines the length of the stroke of the cylinder 4 on the piston 5 as at 1.

In the lower end wall of the hollow body 'of the piston 5 is arranged a valve 8, which co-operates with a seat 9, and which is secured to a link or valve rod I8, which is controlled by a two-armed lever I I, rockable upon a pivot I2. The other end of the two-armed lever II is provided with an aperture I3, through which passes a sleeve I4. The freedom of movement of the sleeve I4 in the aperture I3 is limitedby two anges I5. The sleeve I4 is secured upon a rod I8, the lower end of which is hooked on to a pinrll on a slot guide I8. The above described parts Iii-Il comprise a lost-motion connection between the slot-guide I8 and the valve 8. The slot guide I8 is mounted by its aperture I9 upon the shaft 28 of a cam 2l, which is driven by a belt pulley from the main drive of the machine. The cam 2I acts upon an anti-friction roller 22, which is mounted on the upper part of the slot guide I 8. The slot guide I8 merges at its lower end into a link rod 23, which is connected by a pin 24 on the one hand with a lever 25 and on the other hand with a guiding link 26, which controls a plunger or ram 2l. The lever 25 is rockable about a pin 28 and is rigidly connected with a guard hoop 29, which is in the shape of a horse-shoe, and surrounds the entire working position. A spring 38 constantly tends to turn the hoop 29 about its pivot 28 in a clockwise direction. On the work table 2 there is a projection 3|, of which the part that is capable of coming into contact with the plunger 2'! is provided with a steel inserti-on or facing 32.

In the piston body 5 there is also provided a safety valve 33, which is loaded by a spring 34, which is adjustable by means of a nut 35.

The cylinder 4 is suspended by a rod 36, attachedto a pin 31 on a lever 38, which is rockable upon a roller 39 and is loaded on the other side of its fulcrum by a spring 40. By means of an adjusting screw 4I the height of the cylinder 4 on the piston 5 can be adjusted.

The apparatus described operates in the following manner: In the initial position of the machine, shown in Figure l, that is to say, at the time when the workman is placing the workpiece in the mould I, the roller 22 of the slot guide I8 rests upon the circular portion of the cam 2l, that is to say, it is located in its highest position, in which the valve 8 is opened, the hoop guard 29 raised, and the plunger 21 rocked out of the vertical position. As soon as the workman has placed the work-piece, a shoe sole for example, in the mould I, he starts the machine, by means of a peda1 of theusual kind, not shown, which results in an upward movement of the work table 2, together with the lower mould I, with simultaneous rotation of the cam 2|, which, as the lower mould member I comes within dangerous proximity to the upper mould member 3, moves out of engagement with the roller 22 of the slot guide I8. circumstances, when there. is no obstruction at the working position, the .liberation of the roller 22 by the cam 2Iresults in a downward movement of the slot guide I8, which effects a deflection of the guard hoop 29, likewise in a downward direction, under the action of the pull of the spring 3G, and with simultaneous closing of the valve 8. The valve 8 shuts ofi the seat 9 before the moulds I and 3 come into contact with one another, and remains closed throughout the pressing time. Owing to the closure of the valve 8 there arises between the bottom of the piston and the bottom of the cylinder` 4 a cushion of liquid under pressure, which holds the cylinder 4 in a stationary position. After the termination of the pressing operation the cam 2I again engages with the roller 22, and lifts up the slot guide I8, thereby also causing the ascent of the guard hoop 28 and the re-opening of the valve il.

If however it happens that the workman, in putting the work-piece into the machine, starts the machine before he has withdrawn his hands from the working position, the slot guide cannot pass into its lower position, even though the cam 2| sets the roller 22 of the slot guide I8v free, because the guard hoop 29 is caught by the workmans hand in the position shown in Figure 2, This has in the rst place the result that the valve 8 remains open, since the only partial deflection of the hoop 29, with incomplete descent of the slot guide I8, is not transmitted to the two-armed lever Il, because the sleeve I4 is able to pass freely, to the extent of this partial stroke, through the aperture I3, and the motion of the hoop 29 ceases before the upper ilange l5 begins to act. Owing to the partial displacement of the slot guide I8 downwards, the rod 23 shifts the plunger 21 into a vertical position, in which the plunger 21, as the table 2 ascends, comes into engagement with the steel facing 32 on the projection 3I, so that a gap of suflicient breadth for the hand remains between the lower and upper moulds. As the table 2 moves further upwards, the latter takes along with it, by the plunger 2T, the cylinder together with the mould 3, since the pressure liquid can iiow freely from the space between the bottom of the piston 5 and the bottom of the cylinder 4 through the valve 8 into the cavity of the piston 5. After the pressing strokeof the table 2 has been completed the table 2 descends, the cylinder 4 also descending under the action of gravity along the piston 5, while the pressure liquid ilows back into the space between the bottom of the piston 5, and the cylinder 4. The cam 2i raises the guard hoop 29, and the work- Under normal man can repeat the working operation without an accident occurring, and without a heavy impact in the machine or a violent stoppage occurring which might damage any part of the machine.

I claim:

1. A pressing or like machine, such as a shoesole pressing machine, comprising: a machine frame, a stationary piston secured to the machine frame, a displaceable cylinder enclosing the stationary piston, leaving a space for cushioning iluid between one end of the piston and the adjacent end of the cylinder, a valve shutting oif the said cushioning space, a normally stationary mould member secured to the displaceable cylinder, a movable mould member, means for pressing the movable mould member against the normally stationary mould member, a movable guard hoop surrounding the position of a work-piece placed between the two mould members, connecting means movable into and out of operative position between said mould members for securing unitary movement of said members to prevent closing of the mould and means operable by interruption of movement of the guard hoop to control said valve and move said connecting means into operative position.

2. A pressing or like machine, comprising: a machine frame, a stationary piston secured to the machine frame; a displaceable cylinder enclosing the stationary piston, leaving a space for cushioning fluid between one end of the piston and the adjacent end of the cylinder, a valve shutting oil" the said cushioning space, a normally stationary mould member secured to the displaceable piston, a movable mould member, means for pressing the movable mould member against the normally stationary mould member, a movable guard hoop surrounding the position of a work-piece placed between the two mould members, connecting means movable into and out of operative position between said mould members for securing unitary movement of said members to prevent closing of the mould, means operable by interruption of movement of the guard hoop to move said connecting means into operative position, a slot guide, a link rod connecting the slot guide with the guard hoop, rod and lever mechanism, including a lost-motion connection between the slot guide and the valve, for opening the valve when the guard hoop is raised, and means for raising the slot-guide, and thereby raising the guard hoop and opening the valve when the mould members are separated to enable a workman to place a work-piece in the working position.

3. A pressing or like machine as claimed in claim 2, wherein the lost-motion connection between the slot guide and the valve comprises: a two-armed lever fulcrumed on the machine frame, a link rod connecting one end of the lever with the valve, the other end of the lever being formed with an aperture, a link rod passing through theaperture and attached to the slot guide, and two abutments on this link rod, one on each side of the lever.

4. A pressing or like machine, comprising: a..

means for pressing the movable mold member against the normally stationary mold member, a movable guard hoop surrounding the position of a work-piece placed between the two mold members, a slot guide, a link rod connecting the slot guide with the guard hoop, rod and lever mechanism, including a lost-motion connection between the slot guide and the valve, for opening the valve when the guard hoop is raised, and means for raising the slot guide, and thereby raising the guard hoop and opening the valve after a pressing operation which includes a cam roller on the slot gui-de, a cam co-acting with the cam roller, and means for actuating the cam, the cam being so shaped as to release the roller and allow the slot guide to descend when the movable mold member is approaching the normally stationary mold member.

5. A pressing or like machine, such as a shoesole pressing machine, comprising: a machine frame, a stationary piston secured to the machine frame, a displaceable cylinder enclosing the stationary piston, leaving a space for cushioning fluid between one end of the piston and the adjacent end of the cylinder, a valve shutting 01T the cushioning space, a normally stationary mould member secured to the displaceable cylinder, a movable mould member, means for pressing the movable member against the normally stationary mould member, connecting means movable into and out of operative position between said mould members for securing unitary movement of said members to prevent closing of the mould, a movable guard hoop surrounding the position of the work-piece placed between the two mould members and means operable by interruption of movement of the guard hoop for controlling the valve and moving said connecting means into operative position, the said controlling means preventing the valve from closing until the guard hoop has completed its travel past the working position, so that if any obstruction, such as a work-mans hand, checks the guard hoop, the cushioning uid will escape through the valve, and the normally stationary mould member will move with the movable mould member.

6. A pressing or like machine, such as a shoesole pressing machine, comprising: 1a machine frame, a stationary piston secured to the maf chine frame, a displaceable cylinder enclosing the stationary piston, leaving a space for cushionlng fluid between one end of the piston and the adjacent end of the cylinder, a valve shutting oil the said cushioning space, a normally stationary mold member secured to the displaceable cylinder, a movable mold member, means for pressing the movable mold member against the normally stationary mold member, a movable guard hoop surrounding the position of a workpiece placed between the two mold members, means connected with the guard hoop for controlling the valve, the said controlling means preventing the valve from closing until the guard hoop has completed its travel past the working position, so that if any obstruction, such as a workmans hand, checks the guard hoop, the cushioning uid will escape through the valve, and the normally stationary mold member will yield readily to the pressure of the movable mold member, a work table carrying theY movable mold member, and a movable plunger connected with the guard hoop and adapted to be interposed between the work table and the displaceable cylinder when the guard hoop is in an intermediate position, so that if the guard hoop is checked in that position during a working stroke the plunger will force the displaceable cylinder to participate in the motion of the work table.

'7. In a pressing machine, a movable power operated bottom mold member, a top mold member, a normally closed iiuid chamber operative to limit the movement of the top member, a valve controlling discharge of fluid from said chamber, a ram effective in one position to move said chamber and top mold member with said bottom mold member to prevent closing of the mold, a guard member movably mounted adjacent the mold members, and actuating means operable upon movement of the guard member to move the ram to said position and to simultaneously open said valve.

vAcLAv CHMELAR.

References Cited in the file 0f this patent UNITED STATES PATENTS Number Name Date 1,098,401 Preble June 2, 1914 1,854,888 Davis Apr. 19, 1932 2,263,134 Hoza Nov. 18, 1941 2,324,660 Yanchenko July 20, 1943 2,429,261 Ewaldson Oct. 21, 1947