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EP0496694A2 Expired / Lapsed EP ⏱️ 0.0 years remaining

Method and apparatus for joining thermoplastic workpieces by high frequency vibrations

Assignee: Emerson Electric Co
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Filing: 1992-01-09
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Granted: —
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Expires: 2012-01-09
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Abstract

Abstract A method and apparatus are disclosed for joining a plurality of tubular thermoplastic workpieces (10,12) by causing the workpieces to be stacked with their internal surfaces axially aligned. High frequency vibrations are applied to the respective inner surfaces of the stacked workpieces, the motion of the vibrations being predominantly along the axial alignment of the workpieces. Responsive to the dissipation of the vibratory energy, thermoplastic material from the inner surfaces of the workpieces becomes molten and flows and, upon the cessation of the vibrations, the molten and flowed material rigidifies to cause the workpieces to be joined. The high frequency vibrations, most suitably, are provided by a horn adapted to be resonant as a half wavelength resonator at an ultrasonic frequency in the range between 16 and 25 kHz.

Inventors

  • 👤 Thomas Brinker Sager

Bibliographic Details

Application Number —
Jurisdiction EP
Data Source google_patents
Last Synchronized 2026-11-02 17:48
CPC Classifications
B; B29; B29C; B29C65/00; B29C65/02; B29C65/08; B29C65/06; B29C65/0681; B29C66/00; B29C66/01; B29C66/05; B29C66/10; B29C66/13; B29C66/137; B29C66/50; B29C66/51; B29C66/53; B29C66/534; B29C66/5344; B29C66/54; B29C66/543; B29C66/63; B29C66/70; B29C66/73; B29C66/739; B29C66/7392; B29C66/73921; B29C66/80; B29C66/81; B29C66/814; B29C66/8141; B29C66/81411; B29C66/81421; B29C66/81422; B29C66/816; B29C66/8161; B29C66/83; B29C66/832; B29C66/8322; B29C66/812; B29C66/8122; B29C66/90; B29C66/95; B29C66/951; B29C66/9513; B29L; B29L2031/00; B29L2031/772

Claims Analysis

Total Claims: 16
Claim 1
Independent Claim 118 words
The method of joining a plurality of tubular thermoplastic workpieces comprising: stacking the workpieces upon one another in a manner causing the respective inner surfaces of said workpieces to be axially aligned; causing said workpieces to be in forced contact with one another along their respective radially disposed surfaces; applying during a time interval high frequency vibrations to the respective inner surfaces for causing, responsive to the dissipation of energy provided by said vibrations, thermoplastic material to soften and flow along said respective inner surfaces, and terminating said time interval for causing said vibrations to cease, whereby said softened and flowed thermoplastic material along said inner surfaces rigidifies to cause said workpieces to be joined to one another.
Claim 2
Dependent Claim 26 words
The method of joining a plurality of tubular thermoplastic workpieces as set forth in claim 1, said vibrations having a frequency in the ultrasonic frequency range.
Claim 3
Dependent Claim 42 words
The method of joining a plurality of tubular thermoplastic workpieces as set forth in claim 1, said vibrations having a frequency in the ultrasonic frequency range and an axis of vibration substantially parallel to the axis along which the workpieces are aligned.
Claim 4
Dependent Claim 54 words
The method of joining a plurality of tubular thermoplastic workpieces as set forth in claim 1, said vibrations being applied to said inner surfaces by a side surface portion of a horn dimensioned to be resonant along its longitudinal axis as a half wavelengh resonator at a predetermined frequency in the ultrasonic frequency range.
Claim 5
Dependent Claim 46 words
The method of joining a plurality of tubular thermoplastic workpieces as set forth in claim 4, said side surface portion of said horn being disposed substantially at an antinodal region of axial vibrations of said horn, causing said vibrations to be applied in the shear mode.
Claim 6
Dependent Claim 32 words
The method of joining a plurality of thermoplastic workpieces as set forth in claim 5, said horn being resonant at a predetermined frequency in the range between 16 kHz and 25 kHz.
Claim 7
Dependent Claim 45 words
The method of joining a plurality of thermoplastic workpieces as set forth in claim 4, the inner surfaces of said workpieces being round, said surface portion of said horn being of cylindrical shape and dimensioned to have a snug sliding fit with said inner surfaces.
Claim 8
Dependent Claim 22 words
The method of joining a plurality of thermoplastic workpieces as set forth in claim 7, said workpieces being made from butyrate material.
Claim 9
Independent Claim 180 words
An apparatus for joining a plurality of tubular thermoplastic workpieces comprising: means for supporting the workpieces in staked relationship with the respective inner surfaces of the workpieces in axial alignment; means for causing the stacked workpieces to be in forced engagement along their respective radially disposed surfaces, and a horn dimensioned to be resonant as a half wavelengh resonator at a predetemined high frequency disposed for engaging the respective inner surfaces of the workpieces in a manner causing a potion of the side surface of said horn to be in vibration energy transmitting engagement with the respective inner surfaces of the workpieces for causing, responsive to said horn being rendered resonant for a brief time interval, vibrations substantially along the longitudinal axis of the stacked workpieces to be applied to said inner surfaces, whereby, responsive to the dissipation of vibratory energy, thermoplastic material from the inner surfaces of the workpieces is caused to soften and to flow and said softened and flowed material upon the cessation of said vibrations rigidifies to cause the workpieces to be joined to one another.
Claim 10
Dependent Claim 32 words
An apparatus for joining a plurality of tubular thermoplastic workppieces as set forth in claim 9, said horn being dimensioned to be resonant at a predetermined frequency in the ultrasonic frequency range.
Claim 11
Dependent Claim 29 words
An apparatus for joining of plurality of tubular thermoplastic workpieces as set forth in claim 10, said predetermined frequency being in the range between 16 kHz and 25 kHz.
Claim 12
Dependent Claim 46 words
The apparatus for joining a plurality of tubular thermoplastic workpieces as set forth in claim 9, said means for supporting said workpieces and causing them to be in stacked relationship and axial alignment including a base plate and an axially movable plunger supported by said plate.
Claim 13
Dependent Claim 50 words
The apparatus for joining a plurality of tubular thermoplastic workpieces as set forth in claim 12, said plunger being dimensioned for engaging the respective inside surfaces of the workpieces, and being axially displaced by said horn when the horn is brought into engagement with the inner surfaces of the workpieces.
Claim 14
Dependent Claim 24 words
The apparatus for joining a plurality of tubular thermoplastic workpieces as set forth in claim 13, said plunger being resiliently mounted for axial displacement.
Claim 15
Dependent Claim 54 words
The apparatus for joining a plurality of tubular thermoplastic workpieces as set forth in claim 9, said means for causing said workpieces to be in forced engagement comprising a stripper plate for engaging the topmost workpiece of the stacked workpieces, said stripper plate having an aperture through which said horn is adapted to move.
Claim 16
Dependent Claim 55 words
The apparatus for joining a plurality of tubular thermoplastic workpieces as set forth in claim 9, said portion of said side surface being dimensioned to have a snug sliding fit with the respective inner surfaces of the workpieces, and said portion of said side surface being disposed substantially at an antinodal region of axial vibrations.

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