Claims
- 1. A wire-twisting machine for fabricating straight and contrahelically wound sections comprising:
- means for securing a first wire between first and second fixed end means;
- first and second coaxially spaced pulley wheels located inwardly of the fixed points and having central openings therein through which the first wire passes;
- stationary guide means located between the second pulley wheel and the second fixed end means, the guide means having a coaxially located central opening for allowing the first wire to pass therethrough;
- a second wire secured to a radially outward point on the first pulley wheel and positioned in parallel spaced relation to the first wire;
- radially outward openings formed in the second pulley wheel and the guide means for passing the second wire for securement to a point on the second fixed end means; and
- means for rotating the pulley wheels in synchronous rotation while undergoing limited translation therebetween wherein the second wire is helically wound around the first wire between the second pulley wheel and the guide means while the first and second wires remain parallel and unwound outwardly of the second pulley wheel and the guide means.
- 2. The subject matter set forth in claim 1 together with bearing means engaging the pulley wheel perimeters for permitting their free synchronous rotation.
- 3. The subject matter set forth in claim 1 wherein the radially outward openings on the guide means are displaced by an equal radial distance from the central openings therein.
- 4. A wire-twisting machine for fabricating straight and contrahelically wound sections comprising:
- means for securing a first group of wires between first and second fixed end means;
- first and second coaxially spaced pulley wheels located inwardly of the fixed points and having central openings therein through which the first group of wires passes;
- stationary means located between the second pulley wheel and the second fixed end means, the guide means having a coaxially located central opening for allowing the first group of wires to pass therethrough;
- a second group of wires secured to a radially outward point on the first pulley wheel and positioned in parallel spaced relation to the first group of wires;
- radially outward openings formed in the second pulley wheel and the guide means for passing the second wire group for securement to a point on the second fixed end means; and
- means for rotating the pulley wheels in synchronous rotation while undergoing limited translation therebetween the second group of wires is helically wound as a layer around the first group of wires between the second pulley wheel and the guide means while the first and second groups of wires remain parallel and unwound outwardly of the second pulley wheel and the guide means.
- 5. The subject matter set forth in claim 4 together with bearing means engaging the pulley wheel perimeters for permitting their free synchronous rotation.
- 6. A method for fabricating continuous straight and contrahelical wire sections comprising the steps:
- securing a first group of wires between first and second fixed end points;
- helically winding a median section of a second group of wires, as a layer, around the median section of the first wire group; and
- bundling the outward ends of the first and second wire sets to form corresponding straight sections.
- 7. The method set forth in claim 6 together with the step of helically winding a median section of a third group of wires, as a layer, around the median section of the second wire group to form a contrahelical layer, the outward ends of the third group being then bundled with the bundled ends of the first and second wire group to form straight end sections.
RELATED PATENT APPLICATION
This application is related to my co-pending patent application Ser. No. 507,787, filed Apr. 12, 1990.
The present invention relates to electrical harness fabricating machines, and more particularly to such a machine which is capable of generating straight lay and contrahelic lay sections in a single harness.
In the preparation of complex harnesses, numerous wires are required to be twisted and straight layed. Electrical wires which are bundled and in generally parallel configurations are capable of withstanding torsional displacements along a harness axis. However, this basic type of harness suffers a high failure rate when the harness undergoes sharp bends. This is due to the fact that the inside of the bend places the wires thereat in compression while the wires at the outside of the bend are placed in tension.
Contrahelic harnesses have superior performance characteristics when a harness is to be bent. A contrahelic configuration includes helically wound wires wound in a first sense and comprising a first layer while a second coaxial outer layer comprises helically wound wires which are wound in an opposite sense. Although such contrahelic configurations are superior in the area of bends, they are inferior to straight lay wires along straight sections where torsional displacement is experienced by a harness.
In many situations a length of cable is required which must include bends and straight line sections. Conventionally, this is accommodated by employing connectors between straight lay up and contrahelic lay up sections of a harness. The presence of electrical connectors encourages mechanical failures as the cable undergoes motion in torsional and bending modes.
The present invention eliminates the failures of connectors between straight and contrahelic sections. This is accomplished by forming straight and contrahelic sections of a single uninterrupted wire harness. As a result, the present invention offers high reliability and cable strength where complex harnesses must be employed such as in the field of robotics.
US Referenced Citations (6)
Non-Patent Literature Citations (1)
| Entry |
| "Wire Harness Twisting Aid", NASA Tech. Briefs, Spring 1980, vol. 5, No. 1, p. 111. |
Patent Grant
5020576
