Energy director for ultrasonic welding and joint produced thereby

• US 5,540,808 A
• Filed: 01/30/1995
• Issued: 07/30/1996
• Est. Priority Date: 02/24/1993
• Status: Expired due to Term

• Current Assignee: Deka Products Limited Partnership
• Original Assignee: Deka Products Limited Partnership
• Inventors: Vincent, Douglas E., Durand, Kevin A.
• Primary Examiner(s): Barry, Chester T.
• Application Number:
  US08/380,307
• Time in Patent Office: 547 Days
• Field of Search: 156/73.1, 156/580.2
• US Class Current: 156/580.2
• CPC Class Codes: A61M 39/22 Valves or arrangement of valves A61M39/02, A61M39/0247, A61M39/16 take precedence; regulating valves in infusion systems A61M5/16881; in devices worn by the patient for the reception of urine, faeces, catamenial or other discharge, or in colostomy devices A61F5/4405
• CPC Class Codes: A61M 39/24 Check- or non-return valves
• CPC Class Codes: A61M 39/28 Clamping means for squeezing flexible tubes, e.g. roller clamps tube strippers A61M1/83
• CPC Class Codes: A61M 5/152 pressurised by contraction of elastic reservoirs containers for dispensing contents by contraction of an elastic bag provided therein, in general B65D83/0061
• CPC Class Codes: A61M 5/162 Needle sets, i.e. connections by puncture between reservoir and tube ; Connections between reservoir and tube in jet-action syringes A61M5/30; connectors for tubes having sealed ends and a needle for piercing them A61M39/14
• CPC Class Codes: A61M 5/16809 by repeated filling and emptying of an intermediate volume pressure infusion using positive displacement pumps A61M5/142
• CPC Class Codes: A61M 5/16813 by controlling the degree of opening of the flow line
• CPC Class Codes: A61M 5/16854 by monitoring line pressure
• CPC Class Codes: A61M 5/36 with means for eliminating or preventing injection or infusion of air into body dialysis systems, blood oxygenators A61M1/14; haemofiltration equipment A61M1/34; automatic tube cut-off A61M39/281
• CPC Class Codes: A61M 5/365 Air detectors A61M5/1684 takes precedence; in extracorporeal blood circuits A61M1/3626
• CPC Class Codes: B29C 65/08 using ultrasonic vibrations non-plastics element to plastics elements B29C65/645
• CPC Class Codes: B29C 66/112 Single lapped joints
• CPC Class Codes: B29C 66/114 Single butt joints
• CPC Class Codes: B29C 66/242 said joint lines being closed, i.e. forming closed contours
• CPC Class Codes: B29C 66/30223 said melt initiators being rib-like
• CPC Class Codes: B29C 66/30325 making use of cavities belonging to at least one of the parts to be joined
• CPC Class Codes: B29C 66/53461 joining substantially flat covers and/or substantially flat bottoms to open ends of container bodies
• CPC Class Codes: B29C 66/71 characterised by the composition of the plastics material of the parts to be joined welding bar compositions B29C65/125
• CPC Class Codes: B29C 66/712 the composition of one of the parts to be joined being different from the composition of the other part
• CPC Class Codes: B29C 66/73921 characterised by the materials of both parts being thermoplastics
• CPC Class Codes: B29C 66/8322 : Joining or pressing tools reciprocating along one axis
• CPC Class Codes: B29C 66/9513 : characterised by specific vibration frequency values or ranges
• CPC Class Codes: B29C 66/9516 : by controlling their vibration amplitude
• CPC Class Codes: B29K 2027/06 : PVC, i.e. polyvinylchloride
• CPC Class Codes: B29K 2033/08 : Polymers of acrylic acid esters, e.g. PMA, i.e. polymethylacrylate
• CPC Class Codes: B29K 2055/02 : ABS polymers, i.e. acrylonitrile-butadiene-styrene polymers
• CPC Class Codes: B29K 2069/00 : Use of PC, i.e. polycarbonates or derivatives thereof, as moulding material
• CPC Class Codes: B29K 2075/00 : Use of PU, i.e. polyureas or polyurethanes or derivatives thereof, as moulding material
• CPC Class Codes: B67D 7/0255 : squeezing collapsible or flexible storage containers for dispensing beverages on draught B67D1/0462
• CPC Class Codes: F16K 31/004 : actuated by piezoelectric means
• CPC Class Codes: G01F 1/34 : by measuring pressure or differential pressure
• CPC Class Codes: G01F 1/66 : by measuring frequency, phase shift or propagation time of electromagnetic or other waves, e.g. using ultrasonic flowmeters
• CPC Class Codes: G01F 17/00 : Methods or apparatus for determining the capacity of containers or cavities, or the volume of solid bodies measuring linear dimensions to determine volume G01B
• CPC Class Codes: G01P 13/0066 : by using differences of pressure in the fluid
• CPC Class Codes: Y10T 403/47 : Molded joint
• CPC Class Codes: Y10T 403/477 : Fusion bond, e.g., weld, etc.

Abstract

A process is provided for ultrasonically welding a rigid thermoplastic, such as acrylic, and a flexible thermoplastic, such a polyvinyl chloride (PVC) doped with plasticizers. The rigid piece includes an energy director where the joint is to be located. The energy director includes first and second ridges running the length of the joint and a groove running between the first and second ridges. The energy director is placed against one side of the flexible piece, and an ultrasonic horn against the other side opposite the energy director. The two pieces are then welded together using standard ultrasonic technology. The shape of the energy director promotes the melting and flow of both pieces as they are being welded together.

Claims

1. An energy director for use on a surface which is to be ultrasonically welded to a second thermoplastic piece of material, the surface having a length, the energy director comprising:

a first ridge running the length of the surface;

a second ridge running the length of the surface and substantially parallel to the first ridge; and

a groove running the length of the surface between the first and second ridges,

wherein the energy director is made of a thermoplastic material,

wherein both the first and second ridges have a first side adjacent the groove and a second side opposite the groove the first side of both ridges directly face each other across the groove,

wherein the first ridge'"'"'s first side is steeper than the first ridge'"'"'s second side,

wherein the second ridge'"'"'s first side is steeper than the second ridge'"'"'s second side, and

wherein the ridges and the groove are shaped so as to promote flow of the thermoplastic material toward the groove during ultrasonically welding.

2. An energy director according to claim 1, wherein the surface is located at the end of a wall, the wall having a side, and where the second ridge'"'"'s second side slopes all the way down to the side of the wall.

3. An energy director according to claim 2, further including a ledge, adjacent the first ridge'"'"'s second side.

4. An energy director according to claim 3, wherein the second ridge'"'"'s second side slopes down to a point below the ledge.