1. Field of the Invention
The present invention relates to a pressing system for pressing blanks in a coining, stamping or other press forming process.
2. State of the Art
Known press forming techniques for use, for example, in the coin manufacturing industry use a rotary pressing table (frequently known as a rotary dial plate table) having a vertical rotary axis about which the table rotates. The dial plate table has a series of circumferentially spaced blank receiving stations which pass by a feed outlet at which a respective blank is fed into a respective receiving station. The table is then rotated to a pressing station at which a press forming operation (coin stamping) is carried out. The table indexes rotationally with sufficient dwell time for loading of the blanks into the receiving stations from the feed outlet and performance of the pressing operation. Conventionally, the blanks are fed from an elevated hopper or bowl store (which is periodically loaded with blanks), downwardly into a vertical guide tube to form an upright column or stack of the blanks. Blanks are then fed from the bottom of the vertical stack by means of a reciprocating finger which on its forward stroke forces the lowermost blank sideways from the stack at the feed outlet and into the adjacent dial plate table receiving station.
The prior art system described requires complex timing of the reciprocating finger to pare off the lowermost blank from the stack at the precise moment the dial plate receiving station is in position. This results in frequent failure due to mechanical problems and mis-timing which results in down time to repair. Changeover to run the system for blanks of different sizes requires the stack guide tube, and dial plate receiving station arrangement to be reset. This results in the receiving station distribution about the circumference of the dial plate table changing and as a result the timing of the reciprocating finger of the feed system is required to be altered. This changeover procedure is time consuming and results in significant down time.
An improved technique has now been devised.
According to a first aspect, the present invention provides pressing apparatus for pressing blanks in a coining, stamping or press forming operation, the apparatus including a rotary pressing table to which the blanks are fed, a store receptacle for the blanks and a feed system for feeding the blanks dispensed from the store receptacle to the rotary pressing table, the feed system including a guide conduit into which the blanks pass following dispensing from the store receptacle and along which the blanks are urged to file one behind another to an exit from the guide conduit, the blanks passing directly from the conduit into a receiving station of the rotary pressing table.
According to a second aspect, the invention provides a feed system for feeding blanks from a receptacle store to a rotary pressing table, the feed system comprising a guide conduit into which the blanks pass following dispensing from the store receptacle and along which the blanks are urged to file one behind another to an exit from the guide conduit, the blanks passing directly from the conduit into a receiving station of the rotary pressing table.
According to a further aspect, the invention provides a press forming process in which blanks are fed from a receptacle store of blanks to a rotary pressing table, the blanks passing from the receptacle store into a guide conduit along which guide conduit the blanks are urged to file one behind another to an exit from the guide conduit, the blanks passing directly from the guide conduit into a receiving station of the rotary pressing table.
It is preferred that the blanks comprise disc form elements having opposed major faces and a minor dimension thickness edge. In this context disc form should be read as encompassing within its scope circular, hexagonal octagonal or other polygonal shaped generally flat blanks, having opposed major faces.
Desirably, the rotary pressing table has an upwardly extending axis of rotation. This enables the blanks to be retained on the table by gravity.
Beneficially, the guide conduit extends transversely to the axis of rotation of the pressing table, preferably substantially horizontally (although a slight incline may be permissible, or even aid in progressing the blanks toward the table, if inclined in that direction).
The blanks pass along the guide conduit in edge to edge file relationship, preferably in single file. Preferably, the motion of the blank in passing into the receiving station of the rotary pressing table is in the same general direction as the motion of the blank along the conduit.
The guide conduit is preferably elongate (more preferably generally straight), the blanks desirably moving in a direction in-line with the conduit in passing into the blank receiving station of the rotary pressing table. Desirably the feed system (preferably the guide conduit) has gauging means for rejecting oversize and/or undersize blanks. The gauging means may include an aperture in the conduit through which undersize blanks fall.
Advantageously, the blanks are fed directly to the guide conduit from the receptacle store, in file one behind another. The store receptacle preferably includes a dispensing arrangement for dispensing the blanks in file in edge to edge relationship, to the guide conduit. Desirably, a rotary/centrifugal arrangement urges the blanks to be dispensed from the store receptacle.
It is preferred that the feed system includes a biassing arrangement operational to bias blanks in the guide conduit in the direction of the rotary pressing table. The biassing arrangement preferably comprises a drive arrangement operational to drive blanks in the guide conduit in the direction of the rotary pressing table. The drive arrangement may include an actuator arranged to contact the surface of the blanks in the guide conduit, preferably the underside surface of the blanks filing along the guide channel. The drive arrangement contacting the underside of the blanks is preferred because it requires less re-organisation of apparatus parts when changing over the apparatus to deal with blanks of differing thickness. In one embodiment, it is preferred that an endless belt drive is provided to contact and drive the blanks in file in the guide conduit.
Alternatively, the drive arrangement may comprise a non-contact drive arrangement, such as a linear induction motor, preferably positioned to extend in-line below the guide conduit. By using an induction motor, the number of moving parts for the apparatus is reduced aiding in ease of assembly, re-assembly and down time during maintenance or changeover.
Beneficially, the rotary pressing table rotates between successive positions in which blanks are urged to pass via the exit of the guide conduit into successive receiving stations of the rotary pressing table. A plurality of receiving stations are preferably provided on the rotary pressing table, each beneficially comprising a receiving recess provided in a sector element mounted to the surface of the table. Desirably, receiving stations are replaceable on the rotary table to fit receiving stations for receipt of blanks of varying dimensions.
The invention will now be further described in a specific embodiment by way of example only and with reference to the following drawings, in which;
Referring to the drawings and initially to the prior art system of
The prior art system described requires complex timing of the reciprocating finger (107) to pare off the lowermost blank from the stack at the precise moment the dial plate receiving station is in position. This results in frequent failure due to mechanical problems and mis-timing which results in down time to repair. Changeover to run the system for blanks of different sizes requires the stack guide tube, and dial plate receiving station arrangement to be reset. This results in the receiving station distribution about the circumference of the dial plate table changing and as a result the timing of the reciprocating finger of the feed system is required to be altered. This changeover procedure is time consuming and results in significant down time.
Turning now to the system of the present invention as shown in
When in position on the table, the blanks are rotated to a pressing station (24) at which a press forming operation (for example coin stamping) is carried out. The table indexes rotationally with sufficient dwell time for loading of the blanks into the receiving stations (18) and performance of the pressing operation.
In the embodiment shown in
In an alternative embodiment, the drive arrangement may comprise a non-contact drive arrangement such as a linear induction motor, preferably positioned in-line below the guide conduit. By using an induction motor, the number of moving parts for the apparatus is reduced aiding in ease of assembly, re-assembly and down time during maintenance or changeover. The use of a linear motor also enables simple external adjustment of the drive speed.
The technique and system of the present invention does not require a complex timing arrangement to ensure transfer of blanks to the receiving station (18) at the dial plate table (5). Additionally, when the process run is converted to take blanks of a different size, there is no requirement to make timing adjustments or change feed tubes. The sector elements (16) are simply replaced with sector elements with appropriate sized receiving recesses and the width of the guide channel is adjusted. These features ensure that the operational down time is minimised.
Number | Date | Country | Kind |
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0501594.6 | Jan 2005 | GB | national |
Filing Document | Filing Date | Country | Kind | 371c Date |
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PCT/GB06/00233 | 1/25/2006 | WO | 00 | 5/12/2008 |