Tubular bag closing machine

• US 4,713,047 A
• Filed: 02/18/1986
• Issued: 12/15/1987
• Est. Priority Date: 02/18/1985
• Status: Expired due to Fees

• Current Assignee: Ilapak Research & Development SA
• Original Assignee: Ilapak Research & Development SA
• Inventors: Klinkel, Wolfgang
• Primary Examiner(s): NOT, DEFINED
• Assistant Examiner(s): Showalter, Robert
• Application Number:
  US06/830,641
• Time in Patent Office: 665 Days
• Field of Search: 493/189, 493/199, 493/206, 493/207, 493/209, 493/34, 493/474, 493/475, 493/203, 156/358, 156/583.1, 137/487.5
• US Class Current: 493/34
• CPC Class Codes: B29C 65/18 using heated tools
• CPC Class Codes: B29C 65/305 involving the use of cartridge heaters
• CPC Class Codes: B29C 65/7451 the severing tool and the welding tool being movable with respect to one-another
• CPC Class Codes: B29C 66/1122 Single lap to lap joints, i.e. overlap joints B29C66/45, B29C66/472, B29C66/52272 take precedence
• CPC Class Codes: B29C 66/4312 for making flat seams in tubular or hollow articles, e.g. transversal seams
• CPC Class Codes: B29C 66/81417 being V-shaped
• CPC Class Codes: B29C 66/81419 and flat
• CPC Class Codes: B29C 66/81427 comprising a single ridge, e.g. for making a weakening line; comprising a single tooth
• CPC Class Codes: B29C 66/81431 comprising a single cavity, e.g. a groove
• CPC Class Codes: B29C 66/8242 Pneumatic or hydraulic drives using fluid pressure directly acting on the parts to be joined B29C66/8266
• CPC Class Codes: B29C 66/8246 Servomechanisms, e.g. servomotors
• CPC Class Codes: B29C 66/8322 Joining or pressing tools reciprocating along one axis
• CPC Class Codes: B29C 66/849 Packaging machines
• CPC Class Codes: B29C 66/91 by measuring or controlling the temperature, the heat or the thermal flux
• CPC Class Codes: B29C 66/92211 with special measurement means or methods
• CPC Class Codes: B29C 66/9241 by controlling or regulating the pressure, the force or the mechanical power
• CPC Class Codes: B29C 66/94 by measuring or controlling the time
• CPC Class Codes: B29C 66/961 involving a feedback loop mechanism, e.g. comparison with a desired value
• CPC Class Codes: B65B 51/303 reciprocating along only one axis
• CPC Class Codes: Y10T 137/7761 Electrically actuated valve

Abstract

To provide for uniform pressure, under predetermined conditions, of application of closure sealing jaws for a bag making machine, to close thermoplastic tubular foils, a hydraulic pressure element (7;26,28) applies the pressure of a pressure jaw (1) against another (2), with the foil interposed; the hydraulic pressure is sensed by a transducer (11), converted into an electrical signal and compared with a command set signal (22), any error or deviation being fed back in a closed loop to a servo positioning valve (13,15) to thereby set the hydraulic pressure with which the movable jaw (1) is applied against a fixed jaw (2) in accordance with commanded value.

Claims

1. Tubular bag closing machine having a pair of closing jaws (1, 2) at least one jaw being relatively movable with respect to the other in a closing direction to close the jaws against each other and to seal walls of a tubular plastic element together to form a bag closure, comprising:

a mechanical drive means (5) for moving said at least one of said closing jaws over a fixed path towards the other jaw (2), said mechanical drive means including a rotary-to-linear drive sytem (5, 5a, 18, 20;

     4), providing a fixed displacement path for said at least one closing jaw;

a pneumatic pressure element (7) pressing at least one of said closing jaws (1) against the other (2), said pneumatic pressure element (7) including a pneumatic pressure pillow or cushion (7) located between at least one of said closing jaws (1) and said rotary-to-linear drive system; and

control means for controlling the pneumatic pressure applied to the pneumatic pressure element including

command means (22) for preselecting and modifying a command value of commanded pressure;

a pressure-electrical transducer (11) forming an actual pressure sensing means (11) coupled to and sensing actual pressure at the pneumatic pressure element (7) and providing an actual fluid pressure value;

comparator means (12) connected to receive the command value and the actual fluid pressure value for comparing said values and for providing a deviation signal if the values do not agree; and

a controlled valve means (13,

     15) receiving the deviation value from said comparator means (12) connected to the pneumatic pressure element (7) for controlling pneumatic pressure therein to the level of said commanded value;

said valve means (13) including an inlet line (17a) for pressurized pneumatic fluid and a drain line (17b) and a servo positioning element (15) coupled to the comparator means and selectively opening or closing said inlet and said drain lines (17a, 17b) depending upon the deviation signal, whereby the opening and closing of said valve means need only compensate for a deviation between the command value and the actual pneumatic pressure value;

said command means, said actual pressure sensing means (11), said comparator means, and said control valve means being connected into a closed control servo loop.

2. Machine according to claim 1, wherein an indicator or display (14) is coupled to said comparator means and the indicating, selectively, the actual pressure transduced by said transducer and the command pressure applied to the comparator means by the command means (22).