Metal working – Method of mechanical manufacture – Assembling or joining
Reexamination Certificate
1999-09-10
2001-05-29
Howell, Daniel W. (Department: 3722)
Metal working
Method of mechanical manufacture
Assembling or joining
C029S03300H, C029S03400A, C029S525060, C227S027000, C227S069000, C408S035000
Reexamination Certificate
active
06237212
ABSTRACT:
FIELD OF INVENTION
The present invention relates to a rotary turret head apparatus, and more particularly to a rotary turret head apparatus suitable for use with automatic fastening tools subject to large forming forces.
BACKGROUND OF THE INVENTION
In a number of machine tool applications, multiple operations must be performed successively on a fixed workpiece at the same location. For example, the assembly of the exterior skin of an airplane fuselage may require drilling a hole, inserting a rivet into the hole, upsetting the rivet, and shaving the rivet head. Automatic fastening machines for performing these operations are well known. Such a machine utilizes a controlled transfer head that selectively positions various tools carried by the machine for sequential operation on a workpiece. Typically, the different tools in the transfer head are arranged in linear fashion. The linear carriage enables the tools to be indexed in a straight line into a working position aligned with a work axis that is disposed substantially perpendicular to the plane of the workpiece. A control system moves the tools into and out of alignment with the work axis depending on the required sequence for the manufacturing operation that is being performed. It is common to have separate actuators or feed mechanisms for each tool. The separate feed mechanisms drive the tool toward the workpiece after it has been aligned by the indexing mechanism. Also, certain tools such as drills require drive mechanisms for rotating the tool. Accordingly, the number and different types of mechanisms associated with indexing, feeding and rotating the tools presents a drawback to the linear carriage type systems.
Another drawback to these type of systems is that it is difficult to retrofit the linear carriages of existing machines unless the existing machine has the same number of tool positions.
As an alternative to having independent feed mechanisms for each tool, a centralized feed mechanism capable of engaging with the individual tools can be provided. However, the feed mechanism should be direct coupled to the tools to prevent backlash or chatter, and therefore the single feed mechanism introduces complexity due to the fact that each tool has to be separately brought into alignment and engagement with the central feed mechanism.
There have been tool changers and other machine tool devices that dispose machine tools about a turret perpendicular to the axis of rotation of the turret such as the devices disclosed in U.S. Pat. Nos. 3,296,896; 3,975,109; and, 4,679,276. However, these patents generally disclose turrets designed specifically for cutting tools. The purpose of the turrets disclosed in these patents is to provide tool changers that separately and individually engage different cutting tools with a central drive. Accordingly, the systems include clutches and transmissions for engaging the tools and for driving the tools at different speeds. These systems suffer from some of the same drawbacks discussed above such as the complexity associated with having to separately and individually engage numerous tools with a central drive. Also, these patents address a different problem, namely using a single drive to rotate tools over wide ranges of speeds. Furthermore, none of the prior patents is suitable for use in riveting operations where forming forces can reach into the tens of thousands of pounds.
Accordingly, what is needed is an indexing turret head apparatus that is capable of indexing several tools into a single position relative to a workpiece, that has a single actuator device for all of the tools, that does not require separate engagement of the actuator device with the tools, and that is suitable for use with fastener installation tools for installing fasteners such as rivets where the forming forces for upsetting the rivet are typically in the range of tens of thousands of pounds.
SUMMARY OF THE INVENTION
The present invention meets the above described need by providing a rotating turret head apparatus that has a plurality of tools mounted perpendicular to the axis of rotation of the turret, that has a single actuating mechanism for feeding the tools to a workpiece, and that is suitable for use in installing fasteners where forming forces are in the tens of thousands of pounds.
By mounting the tools perpendicular to the axis of rotation of the turret, a single actuator can be used to feed all of the tools toward the workpiece without the need for separate engagement of a central actuator with each tool. The tools are disposed around the periphery of the turret with sufficient space between adjacent tools such that there is sufficient clearance between the inactive tools and the workpiece to avoid obstruction or damage to the workpiece. Also, because the tools do not have individual actuators and do not have to individually engage with a central actuator, the mounting of the tools is simplified greatly. Each tool can be removably mounted to the turret and can be independently powered by its own source. Accordingly, the individual sources can operate at different frequencies and rpm's and can be powered continuously or powered intermittently depending on the specific application. Also, there can be a greater number of tool mounting positions on the turret than there are tools in order to provide for future expansion. In addition, because the only requirement is mounting the tools to the turret, it is relatively easy to substitute different types of tools into the system with little or no modification.
Accordingly, the turret head apparatus has a turret with an axis of rotation and a plurality of tool mounting positions disposed around the turret. A plurality of fastener installation and machining tools are removably attached to the tool mounting positions on the turret and are disposed substantially perpendicular to the axis of rotation of the turret.
A drive system rotates the turret to index the tools into a working position aligned with the work axis. The turret is preferably connected to a shaft that is mounted on a set of bearings disposed inside a frame. The frame supports both the turret and the drive system. When the tool attached to the turret has to be fed toward the workpiece, the entire frame is moved by an actuating mechanism. The actuating mechanism is capable of moving the frame to bring the fastener installation tool into engagement with a cooperating fastener tool such as an opposing ram to install a fastener.
A guide structure such as a set of guide rails is disposed about the frame such that the frame is maintained in substantial alignment with the workpiece as it travels toward and away from the workpiece.
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Perrelli John Michael
Saunders Cheyenne
Speller, Jr. Thomas H.
General Electro Mechanical Corp.
Hodgson & Russ LLP
Howell Daniel W.
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