Metal fusion bonding – Process – With clamping or holding
Reexamination Certificate
1998-12-29
2001-09-04
Elve, M. Alexandra (Department: 1725)
Metal fusion bonding
Process
With clamping or holding
C228S049300, C228S044500, C228S047100, C269S043000, C269S037000
Reexamination Certificate
active
06283361
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a jig used for holding and fixing a part material during manufacturing of a part, or holding a part during inspection thereof, and in particular to such a jig that is generally used for a plurality of types of parts.
2. Description of the Prior Art
In manufacturing plants, jigs are used for holding part materials during assembling or welding of the parts, fixing for example.
When an exhaust pipe for an automobile is assembled by connecting two pipes to front and rear ends of a muffler by welding, for example, a jig is used for holding the pipes and the muffler in predetermined positions. In such a jig, clamps for holding appropriate portions of the muffler and the pipes are fixed to a base, so that the muffler and the pipes are positioned relative to each other according to a certain design.
To ensure sufficient high rigidity for supporting considerably heavy part materials, and avoid distortion during welding, the jig itself has a large weight, e.g., about 20 kg when it is used for a small-sized exhaust pipe.
In the case of exhaust pipes for automobiles, in particular, numerous different types of exhaust pipes are manufactured depending upon the types and versions of automobiles. In the real situation, jigs used in the manufacture of the exhaust pipes are specialized for respective types of products. Namely, a particular jig is used exclusively for each type of exhaust pipe. Thus, there has been a conventional problem that jigs having large weights must be handled each time the type of exhaust pipes manufactured on an assembly line is changed to another type, and heavy work is required for setting up the jigs.
Also, jigs used in the manufacture of products need to be stored for several years after shutting down the production line, for the purpose of production of spare parts. With an increase in the number of jigs stored, the storage space is increased, and increased time and labor are required for putting the jigs into and taking them out of the storage space. This has been a major problem in management of plants.
Similar problems concerning the known jigs are encountered in the case of jigs used for assembling other parts or inspecting those parts.
SUMMARY OF THE INVENTION
It is therefore an object of the present invention to provide a general-purpose jig which is able to easily provide a desired function of holding and fixing parts suitable for new types of products, without requiring heavy work upon changes of the type of parts to be assembled or inspected, and which can be stored in a significantly reduced storage space.
To accomplish the above object, the present invention provides a general-purpose jig comprising: a base; a locational holding device mounted on the base, and comprising a tripod robot that includes three expansion actuators; and a clamp attached to the locational holding device. In the jig, the position of the clamp can be changed by changing the length of each of the expansion actuators, depending upon an object to be held, according to a command from a control device.
In the general-purpose jig constructed as described above, when at least one of the expansion actuators of the tripod robot is expanded or contracted in response to a command from the control device, the clamp attached to the locational holding device is moved in three-dimensional space.
Since a plurality of locational holding devices can be mounted on the base, and the clamp of each holding device can be placed in a desired position by changing the length of each of the three expansion actuators, a single jig including the plural holding devices can handle a plurality of objects to be held.
In one preferred form of the invention, the tripod robot further includes a lower substrate, an upper substrate, and a rotation inhibiting mechanism provided between the lower substrate and the upper substrate for inhibiting torsional rotation of the lower and upper substrates relative to each other, and the three expansion actuators are located between the lower substrate and the upper substrate. Also, the locational holding device further comprises a three-axis rotary unit comprising elements that can be rotated about three axes that intersect at right angles with each other, and the three-axis rotary unit operates according to a command from the control device. With this arrangement, the position of the clamp can be controlled as desired, and the angle of the clamp can be also controlled as desired by means of the three-axis rotary unit provided between the tripod robot and the clamp.
The rotation inhibiting mechanism may include two parallel sleeves that are connected to the lower substrate with two degrees of freedom and spaced apart from each other by a given distance, and two slide rods that are fixed to the upper substrate and extend in parallel with each other, such that the two slide rods are guided by the sleeves. Thus, the rotation inhibiting mechanism has a simple structure including the parallel sleeves connected to the lower substrate, and the slide rods fixed to the upper substrate and received in the sleeves. Further, since the slide rods are slidable along the parallel sleeves, the rotation inhibiting mechanism can deal with changes in the distance between the lower substrate and the upper substrate due to expansion and contraction of the expansion actuators.
In another preferred form of the invention, the expansion actuators of the tripod robot and the three-axis rotary unit are driven by stepping motors or servo motors, and the control device includes computing means for calculating a displacement of each of the expansions actuators and the three-axis rotary unit, and controls a rotating angle of a corresponding one of the stepping motors or servo motors, according to the displacement. By controlling the rotating angles of the stepping motors or servo motors, the expansion actuators and three-axis rotary unit can be easily and surely positioned to achieve respective displacements calculated by the computing means.
The control device may control the three-axis rotary unit while the tripod robot is being operated to move the clamp or after the movement of the clamp, so that the clamp maintains a predetermined or constant posture. This makes it easy to perform teaching operations on the control device.
The control device may further include manual operating means for operating the tripod robot and the three-axis rotary unit as desired, and storage means, and the computing means may calculate displacement data or related position data of the tripod robot or the three-axis rotary unit that is operated by the manual operating means, and store the displacement data or related position data into the storage means. This arrangement allows teaching operations to be performed automatically.
Preferably, the control device further includes a display on which the current displacement data or related position data of the tripod robot or three-axis rotary unit is displayed. This allows the user to confirm the displacement or position data set in the teaching mode.
REFERENCES:
patent: 4569627 (1986-02-01), Simunovic
patent: 5312096 (1994-05-01), Jasper
patent: 6059703 (2000-05-01), Heisel et al.
Arai Takahiko
Kikuchi Daisuke
Maki Yuzuru
Ohkawara Masahiro
Saito Shin-ichi
Calsonic Corporation
Elve M. Alexandra
Rossi & Associates
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