GB2170443A

GB2170443A - Pressure and lifting mechanism for a pressing apparatus

Info

Publication number: GB2170443A
Application number: GB08602450A
Authority: GB
Inventors: David Weisfeld
Original assignee: Individual
Current assignee: Individual
Priority date: 1985-01-31
Filing date: 1986-01-31
Publication date: 1986-08-06
Also published as: GB8602450D0; GB2170443B; GB8502379D0

Abstract

A pressure and lifting mechanism for a pressing apparatus has upper and lower pressing member (3,4), the lower pressing member (4) being mounted on side support members (2) whilst the upper pressing member (3) is mounted on a lifting arm (1) whose leg (1a) is connected to the side support members (2) by pivot points (6). An operating pressure lever (7) is pivoted at (8) and has a link level (9) pivoted thereto at (10). The other end of the link lever (9) is pivoted at (13) to the ends of two pressure link levers (11 and 12) whose other ends are respectively connected to the leg (1a) at pivot point (14) and side support member (2) at pivot point (15). A spring (17) is connected between common pivot point (13) and the side support member (2) at (18). When the upper pressing member (3) is lowered onto the lower pressing member (4) by means of the operating lever (7) the link lever (9) forces the two pressure levers (11,12) to the over-centre position in relation to the pivot point (13), where the spring (17) then causes the upper pressing member (3) to be firmly held in contact with the lower pressing member (4). <IMAGE>

Description

SPECIFICATION Pressure and lifting mechanism for a pressing apparatus The present invention relates to a pressure and lifting mechanism for pressing apparatus which is provided with upper and lower pressing members.

In particular, the invention relates to a pressure and lifting mechanism which creates pressure by a manual leverage system which also has the capability of raising a lifting arm. Although the invention is applicable to any pressing apparatus the main embodiment described herein particularly applies to heat pressing apparatus which is provided with upper and lower pressing members either or both of which may be heated and which is commonly used for various processes in the clothing, printing and allied industries for such operations as fusing, bonding, transfer printing, motif application and other similar processes.

One known type of pressing apparatus has previously been disclosed in British Patent Specification No. 1,319,233, which apparatus includes upper and lower pressing members, two arms mounted in parallel relation connected to the upper pressing member and pivotally mounted on a supporting frame which itself supports the lower pressing member, spring biassed toggle linkage connecting the arms to the supporting frame, and an operat ing handle for lowering and raising both arms si multaneously.

Another known type of pressing apparatus has previously been disclosed in my British Patent Specification No. 2,058,656. This Specification discloses manual pressing apparatus having upper and lower pressing members, and a support mem ber having a frame and an arm pivotally mounted on the support frame and attached to the upper member by lugs and bolts. A handle attached to the arm allows the upper member to be manually pressed against the lower member. A mechanical connection includes two rotatable link pieces con necting the arm to the supporting frame. A mem ber pivotable relative to the arm is provided with an adjustable abutment part which abuts against one of the link pieces.Another handle enables the pivotable member to pivot relative to the arm in order to bring the abutment part into contact with the link pieces so as to increase pressure between the two pressing members.

The above described types of pressing apparatus have certain disadvantages both with regard to their construction and operation. In the case of the apparatus disclosed in Specification 2,058,656, it requires two separate manual operations in order to achieve the desired pressing operation since the two handles have to be operated in sequence.

Moreover, the release of the upper pressing member from the lower pressing member, in the above constructions is awkward and requires con siderable physical strength from the operator.

It is therefore an object of the present invention to overcome partially or wholly the above disad vantages.

In its broadest aspect, the pressure and lifting mechanism includes manual operable means for lowering the upper pressing member onto the lower pressing member; a link mechanism coupled between the manual operable means and a location fixed with respect to the lower pressing member, said link mechanism applying pressure by mechanical leverage to force the upper pressing member into pressurized contact with the lower pressing member; and means for holding said pressurized contact between the pressing members.

The means for holding the pressurized contact between the two pressing members, may comprise an over-centering arrangement of the link mechanism. Alternatively latching means may be provided for holding the two pressing members in pressurized contact. The latching means may comprise a catch or an electrical actuating contact.

The link mechanism preferably comprises three link levers. In a preferred form an end of each of the three levers is connected by a common pivot point. A first link lever may transmit movement of the manual operating means to the common pivot point. The other two levers are arranged so that displacement of the common pivot point in relation to their other ends as the two pressing members are closed to make contact, causes an over-centering action to take place.

In alternative forms the pivotable connection between the two link levers which form the over-centering action, may be displaced along one of said levers with respect to the point at which one of them is connected to the first link lever.

In the case where the means for holding the pressurized contact between the two pressing members comprises the over-centering arrangement of the second and third link levers, means may be provided to force the link levers back past the over center position after the lapse of a predetermined time from the time of closure of the two pressing members.

Said means may be a pneumatically or hydraulically operated device or an electro-magnetically operated solenoid in conjunction with a timer to cause actuation thereof after a predetermined time delay from being started by a microswitch.

The present invention will now be described in greater detail by way of examples with reference to the accompanying drawings, wherein: Figure 1 is a diagrammatic elevation view of one preferred form of pressing apparatus for fusing, bonding, transfer printing or motif application in the clothing industry; Figure 2 is a diagrammatic elevation view of the leverage mechanism when the upper pressing member of the pressing apparatus shown in Figure 1 is in the lowered position; Figure 3 is a diagrammatic elevation view of the leverage mechanism when the upper pressing member is in the raised position; Figures 4A and 4B are diagrammatic views showing alternative arrangements of the link levers; Figure 5 is a part diagrammatic elevation view of an alternative construction of the pressing apparatus shown in Figure 1; and Figure.6 is a detail of the construction shown in the Figure 5 alternative embodiment.

Referring first to Figure 1 which shows a pressing apparatus suitable for fusing bonding, transfer printing, or motif application in the process of manufacturing of clothing, the pressing apparatus comprises: a stationary lower pressing member 4 mounted on and supported by a pair of side support members 2; and a movable upper pressing member 3 which is pivotally connected to a lifting arm I by means of a hinge 21.

The lifting arm 1 is shaped so that a lower leg 1a thereof projects downwards at an angle which is approximately 90 degrees so that a pivoting position 14 can be provided for the leverage mechanism at the lower end of the lower leg 1a of the lifting arm 1. The lifting arm 1 is connected to the side support members 2 via pivot points 6 about which the whole of the lifting arm 1 pivots thus allowing the upper pressing member 3 to be lifted and lowered by force exerted at 14. The side support members support the lifting arm 1 through the pivot points 6.

The stationary lower pressing member 4 is mounted on and supported by the side support members 2, whilst the upper pressing member 3 can be brought into contact with the lower pressing member 4 and pressure created between them by the leverage and lifting mechanism which will now be described in greater detail.

The leverage and lifting mechanism consists of an operating pressure lever 7 connected to the lifting arm 1 through a pivot 8 about which it can pivot and also connected through a pivot 10 to an upper link lever 9 at its upper end. The upper link lever 9 is connected at its lower end through a common pivot point 13 to two pressure link levers 11 and 12,the arrangement being designed such that all three link levers are able to pivot on the common pivot 13. The other end of the link lever 11 is attached to a pivot point 14 on the lower leg la of the lifting arm 1. The other end of the link lever 12 is attached to the side support members 2 at a pivot point 15.

A tension spring 17 is connected between the common pivot point 13, which is the junction between the two link levers 11 and 12, and a point 18 on the side support members 2. Instead of using a tension spring, any other suitable mechanical device, e.g. a pneumatic or hydraulic cylinder can be used instead. Instead of the first end of the tension spring or other mechanical device being connected to the pivot point 13, it could in alternative forms, be connected to either one of the two link levers 11 and 12.

The leverage mechanism is shown in greater detail in Figure 2 when the upper pressing member 3 is in the lower position and has been urged by the pressure created by the leverage mechanism against the lower pressing member 4.

The operating pressure lever 7 is in the lowered position and in that position the downwards pressure created on the upper link lever 9 through the pivot position 10 causes the two pressure link levers 11 and 12 to be forced passed the position in which they arse parallel with each other to cremate an over-centre situation. The downwards force of the upper link lever 9 onto the common pivot 13 and thus onto link levers 11 and 12 causes the lifting arm 1 to pivot about the pivot point 6 so-that the upper pressing member 3 is urged into contact with the lower pressing member 4.This is caused by the lateral force created at the pivot point 14 on the lower leg 1a of the lifting arm 1 by the link lever 11, the position at which it is connected to the lower leg of the lifting arm 14 being forced away from the fixed and immovable connection of link lever 12 to the side support members 2 at the pivot point 15.The leverage created by the ratio of the pivot point 10 to the operating lever 7 and the resulting leverage advantage at the pivot point 13 onto the two pressure link levers 11 and 12 allow the operator by lowering the operating pressure lever 7 from a position 19 to force the link levers 11 and 12 into an over-centre situation this causing the upper pressing member 3 to be forced, under the pressure created by the leverage advantage in the pressure created at the pivot point 13 onto the two pressure link levers 11 and 12, into firm contact with the lower pressing member 4.

The over-centre situation of link levers 11 and 12 causes the upper pressing member 3 and lower pressing member 4 to become locked together and the operating pressure lever 7 will become locked in the down position thus eliminating the need for the operator to hold down the operating pressure lever 7 at the forward position 19 thereof.

When the operating pressure lever 7 is raised enough to cause the over-centre situation of the two pressure link levers 11 and 12 to no longer exist the "locked down" mode of the operating pressure lever 7 and thus the upper pressing member 3 will also cease to exist.

Once the three position pivot 13 has been raised passed a position in which the two pressure link levers 11 and 12 are parallel with each other, the pivot point 14 will be drawn in an arc, the centre of which is the pivot point 6 in the direction of the force of the spring 17 or whatever mechanical force is provided. The pivoting of the lifting arm 1 about the pivot point 6 by the aforementioned means causes the upper pressing member 3 to be raised from its contact with the lower pressing member 4. Thus the lifting of the operating pressure lever 7 from the forward operating position 19 and the resulting lifting of the upper link lever 9, allows the upper pressure member 3 to be raised once the over-centre situation of the two link levers 11 and 12 has been passed.

Referring now to Figure 3, in which the upper pressing member 3 is shown in the raised position, the two pressure link levers 11 and 12 have been raised from the common pivot 13 so that the link levers 11 and 12 are no longer in an over-centre situation. The common pivot 13 is pulled by the spring 17 in an arc, the centre of which is in the pivot point 15 at which link lever 12 is attached to the side support members 2. The direction of the force of the spring 17 represented by the arrow F causes the common pivot 13 and thus position 14 on the lower leg of the lifting arm 1, to which is attached the other end of the link lever 11, to be pulled in the direction of force of the spring. Thus the lifting arm 1 is pivoting at its pivot point 6 and the upper pressing member 3 rises to its raised position.

In the above described embodiment the spring 17 will immediately pull the upper pressing member 3 up to its raised position as soon as the overcentre situation of the link levers 11 and 12 has been reversed and thus the operator need only to raise the operating pressure lever 7 enough to reverse the over-centre situation of link levers 11 and 12 to cause the effect of the lifting spring 17 to raise the upper pressing member 3 to its fully raised position without any effort by the operator.

In a modified form of the embodiment shown in Figures 1 to 3, the pressing apparatus may be provided with mechanical or electro-mechanical means to cause the over-centre situation of the two pressure link levers 11 and 12 to be reversed.

As shown in dotted outline in Figure 2 of the drawings an electro-magnetically operated solenoid device 20 is mounted on the supporting members 2, so as to be situated underneath the pivot point 13 when the upper pressing member 3 is in the lowered position.

Instead of using an electro-magnetically operated solenoid device a pneumatic or hydraulic device comprising a cylinder and piston arrangement can be substituted.

In order to release the upper pressing member 3, the device 20 is actuated or energized in order to force the pivot point 13 up past the over-centre positon so that the spring 17 comes into effect and raises the upper pressing member 3 to its raised position. By means of the device 20 automatic or semi automatic operation of the apparatus may be used in which the operator manually lowers the upper pressing member 3 and locks it under pressure against the lower pressing member 4 by lowering the pressure operating lever 7 until the pressure link levers 11 and 12 over-centre.At this point a timing device may be started by the operation of a microswitch, so that at the end of the predetermined set time, the timing device will send out an electrical signal to actuate the device 20 which in turn will cause the over-centering of the link levers 11 and 12 to be reversed thus enabling the upper pressing meber 3 to return to its raised positon automatically without operator assistance.

In an alternative form means may be provided to adjust the length of upper link lever 9 or one of the other link levers by such means as a screw thread adjuster so that the point at which link levers 11 and 12 will over-centre is changed and by this means the pressure between the upper pressing member 3 and lower pressing member 4, when the pressure operating lever 7 is in the locked down position, is adjusted.

In yet another alternative form more than one of the leverage mechanisms may be used in a single apparatus in order to achieve greater and more even pressure on longer pressing members.

In another modified form means of damping the force of the spring 17 when the upper pressing member 3 is being raised, can be provided.

Referring now to the modified forms shown in Figures 4A and 48, the position at which link levers 11 and 12 are connected is different from the position at which the upper link lever 9 is connected to one or other of the two pressure link levers which may be extended so that the upper link lever 9 is connected at the end of one of the two pressure link levers so that the common pivot point 13 where the two link levers are connected is not the same pivot point as the pivot point 23 where the upper link lever 9 is connected to one of the link levers.

As shown in Figure 4A, the pivot point 13 is approximately one third of the distance along the link lever 11 from the pivot point 23, whilst in Figure 4B, the pivot point 13 is approximately one third of the distance along the link lever 12 from the pivot point 23.

Referring now to Figure 5, a spring 24 or other means of creating force such as a pneumatic cylinder can be used to create enough upwards pressure when connected at one end near to the common pivot point 13 and at the other end to a suitable position on the lifting arm 1, to cause the over-centre situation of link levers 11 and 12 to be reversed if the operating pressure lever 7 is free to rise. In this embodiment another means needs to be used to cause the upper pressing member 3 and operating pressure lever 7 to lock in the down position.

The preferred means for achieving this is shown in dotted outline at 25 and can be a mechanical catch mechanism or electro-magnetically operated holding device. In this case of a mechanical catch mechanism, the device is designed to engage a part (not shown) on one of the side support members 2 when the upper pressing member is lowered onto the lower pressing member. The device 25 will prevent the operating pressure lever 7 from springing upwards by the force of the spring 24.

The catch device 25 may be released manually or by electrical or pneumatic or similar impulse which is effected by the operator of the apparatus pressing a suitable switch or button or by a microswitch being activated when the upper pressing member 3 is being lowered. In this latter case, the operation of the microswitch starts a timing device which itself sends out the electrical impulse to release the catch device 25 after the time set has expired. In this way the apparatus can be operated in a semiautomatic mode whereby the upper pressing member 3 is lowered and the operating pressure lever 7 also locked down manually but the operating pressure lever 7 is released and upper pressingmember 3 caused to be raised to its open position automatically after set time has expired.

In a further embodiment of the invention as shown in Figure 6, means are provided to adjust the pressure between the upper pressing member 3 and lower pressing member 4 by moving the pivot point 15 closer to or further away from the pi vot point 14.

This adjustment means is in the form of a screwthreaded rod 26 which passes through a tapped hole in the pivot point 15 and an apertured lug 27 connected to the support members 2. Thus in this construction the pivot point 15 of the link member 12 is no longer directly coupled to the support member 2, but via the screw-threaded rod 26. The end of the screw-threaded rod 26 which is juxtaposed to the lug 27 is provided with a knob 28. Rotation of the knob 28 in either the clockwise or anti-clockwise direction causes the pivot point 15 at the end of the link member 12 to move to the left or the right respectively as shown in the drawing. The pivot point 15 at the end of the link member 12 may thus be adjusted either towards or away from the pivot point 14 at the remote end of the other link member 11, and is locked in position by means of a threaded nut 29.The closer the pivot point 15 is moved towards the pivot point 14 the higher the pressure between the upper pressing member 3 and the lower pressing member 4 when the operating pressure lever 7 is locked down. Any other suitable mechanical means of increasing the pressure between the upper pressing member 3 and the lower pressing member 4 may be used.

Whilst in the above described embodiments over-centering of the link levers takes place and therefore principally acts as the means for holding pressurized contact between the upper and lower -pressing members, it is not essential that an overcentering of the two link levers need occur. In the alternative construction the link levers 11 axnd 12 may not quite reach the over-centre position, provided they exert the necessary pressure between the upper and lower pressing members. In this case it is of course essential that the catch mechanism be provided so as to constitute the means for holding pressurized contact between the two pressing members 3 and 4.

A number of further modifications of the pressure and lifting mechanism for a pressing apparatus are possible within the scope of the invention.

In particular, for particularly large machines, there may be up to four side support members required and three lifting arms.

Claims

1. A pressure and lifting mechanism for a pressing apparatus having upper and lower pressing members in which the upper pressing member can be raised and lowered with respect to the lower pressing member, said mechanism including: manual operable means for lowering said upper pressing member onto the lower pressing member; a link mechanism coupled-between said manual operable means and a location fixed with respect to the lower pressing member, said link mechanism applying pressure by mechanical leverage to force said upper pressing member into pressurized contact with the lower pressing member; and means for holding said pressurized contact between said uoper and lower pressing members.

2. A mechanism according to claim 1, wherein the means for holding the pressurized contact be tween the upper and lower pressing members comprises an over-centering arrangement of the link mechanism.

3. A mechanism according to claim 1 or 2, wherein the link mechanism comprises three link levers.

4. A mechanism according to claim 3, wherein an end of each of the three link levers is connected to a common pivot point, a first link lever transmit ting the movement of the manual operating means to the common pivot point, the second and third levers being arranged so that displacement of the common pivot point in relation to their other ends, during the closing operation causes an over-cen tering action to take place.

5. A mechanism according to claim 4, wherein spring urging means are connected between the common pivot point and a fixed location with re spect to the lower pressing member.

6. A mechanism according to claim 1, wherein the means for holding the pressurized contact be tween the upper and lower pressing members comprises latching means associated within oper ating lever constituting the manual operable means and a part of the support members for the lower pressing member.

7. A mechanism according to claim 6, wherein said latching means comprises a mechanical catch mechanism and has an associated timer, which after being activated on closing of the pressing members, effects the automatic release of the catch mechanism after the lapse of a predeter mined time set in the timer.

8. A mechanism according to claim 3, wherein a first link lever transmits the movement of the manual operating means to the end of a second link lever by means of a pivot point, the third link lever having one end connected to the second link lever by means of a pivot point located a distance along the second link lever from the pivot point which connects it to the first link lever.

9. A mechanism according to any one of the preceding claims 4 to 7, wherein spring urging means is connected between said common pivot point and an end of the manual operable means remote from the end at which manual force is ap plied.

10. A mechanism according to claim 4 or 5, wherein means is provided to force the second and third link levers back past the over-centre position after the lapse of a predetermined time from the time of closure of the upper and lower pressing members.

11. A mechanism according to claim 10, wherein said means is a pneumatically or hydrauli cally operated device associated with a timer to cause actuation thereof after a predetermined time delay which is activated by means of a micros witch.

12. A mechanism according to claim 10, wherein said means is an electro-magnetically op erated solenoid associated with a timer to cause actuation thereof after a predetermined time delay which is actuated by means of a microswitch.

13. A mechanism according to claim 4, wherein means are provided for adjusting the relationship of the ends of the second and third link levers in relation to one another, thereby adjusting the pressure which the over-centering action places on the pressing members when in the closed position.

14. A mechanism according to claim 13, wherein said asdjustment means comprises a screw-threaded rod which passes through a tapped hole in the end of one of the link members, the other end of the rod being fixed in longitudinal location with respect to the lower pressing member but free to rotate to effect said adjustment.

15. A pressing apparatus incorporating a pressure and lifting mechanism constructed substantially as herein described with reference to and as illustrated in the accompanying drawings.