Presses – Automatic or material triggered control – Of actuating means
Reexamination Certificate
1999-09-29
2001-11-20
Gerrity, Stephen F. (Department: 3721)
Presses
Automatic or material triggered control
Of actuating means
C100S100000, C100S226000, C100S913000, C227S152000
Reexamination Certificate
active
06318251
ABSTRACT:
BACKGROUND OF THE INVENTION
The present invention is directed to a machine for fabrication of roof trusses and, more particularly, to an automatic control system for such a machine for fabrication of roof trusses. A number of additional features and objects will be apparent in connection with the following discussion of preferred embodiments and examples.
Pitched roofs are commonly supported by roof trusses. Roof trusses are commonly constructed of wood, particularly for wood-framed structures and residences. Roof trusses are manufactured in a wide variety of shapes and sizes according to the needs encountered in erecting a specific building. Because the roof line is usually fairly uniform throughout much of the length of a single building, many identical trusses are needed for a single building.
It has long been known that such trusses can be fabricated more efficiently through use of a truss table than they can by manual methods at the job site. The truss table is setup so that each precut piece of a particular truss fits into a channel created by parallel raised members fastened to the top of the truss table. When all the pieces for a single truss have been put in place on the truss table, they are fastened together. Nails, staples, and other similar fasteners have long been used. For some time, it has been common practice to fasten many of the joints, particularly those bearing greater loads, with connector plates, which consist of a flat plate having a large number of downward projecting parallel spikes generally created by pressing a flat plate within a specially designed die. A connector plate is seated on both the top and bottom sides of the joint as the truss lies on the truss table.
The connector plates may be seated by hammering or the like. Substantial forces are required to seat the connector means of a machine.
A truss fabricating machine includes a gantry movable along an X-axis and a pressing cylinder suspended from the gantry which is movable along the Y-axis allowing the pressing cylinder to be located above a joint in a wooden truss. The pressing cylinder presses down to seat connector plates into selected joints of the truss. A joystick generates electrical signals proportional to the direction and extent of movement of the joystick by the operator, which are converted to pulse width modulated electrical signals in a driver, whose output controls proportional solenoids that drive infinite positioning four-way hydraulic valves to actuate hydraulic motors that drive the gantry and pressing mechanism along either the X-axis, or through a separate hydraulic circuit, the Y-axis. The pressing cylinder can be moved along both axes simultaneously. When the pressing cylinder is in the desired position, a thumb switch on top of the joystick is actuated, causing the ram of the pressing cylinder to descend until it seats the connector plate. Releasing the thumb switch causes the ram to move upward to the top of its stroke.
What is needed is an automatic or partially-automatic control system for such a truss fabrication machine to enhance the efficiency and ensure the maintenance of quality standards in the fabrication of trusses.
SUMMARY OF THE INVENTION
It is an object of the invention to provide a truss fabrication machine with a processor or computer-implemented control system for automating or partially automating the fabrication of trusses thereon.
It is another object of the invention that such a processor or computer-implemented control system for a truss fabrication machine include access to storage devices for retrieval of pre-programmed or “canned” profiles of diverse truss configurations.
It is an alternate object of the invention that the above truss fabrication machine incorporate a manual command controller for not only operating the machine in a manual mode, but also for programmning the processor or computer-implemented control system by virtue of manually sequencing the machine through a given profile and having the processor or computer-implemented control system RECORD such sequence for automatic PLAY BACK later.
It is an additional object of the invention that the foregoing processor or computer-implemented control system include an editor for coding and/or editing the encoded instructions which govern such processor or computer-implemented control system.
These and other aspects and objects are provided according to the invention in a truss fabrication machine that is linked with processing circuitry for partially automating the fabrication of trusses. One or more workers place in jig stops on the tabletop a set of loose pre-cut truss members and the connector plates that get seated at the joints therebetween. The machine has a pressing head for seating the connector plates, which rides on a gantry above the tabletop in generally a Y-axis, wherein the gantry rides on a track generally along an X-axis. There are drivers to drive the gantry along the track and the pressing head along the gantry, as well an actuator for the pressing head. The processing circuitry is reliant on X- and Y-axis sensors for reckoning position on the tabletop. The processing circuitry is given control over the gantry, the pressing-head driver and actuator for coordinating movement of the gantry and pressing head between one given X and Y position to succeeding X and Y positions, and then actuating or not the actuating means. Alternatively, the pressing head might pause in a standby mode following completion of a given truss sufficiently long to allow a worker to remove the completed truss and place back in the jig stops the loose pre-cut truss members and the connector plates, and so on, which will allow the fabrication of a succeeding truss, repetitively.
In one example of the invention, pressing-unit moving means may comprise a motor, a drive shaft, and a drive transmission for driving the pressing unit along the gantry. That way, the Y-axis sensing means might comprise a shaft encoder coupled to the motor shaft for generating signals corresponding to Y-axis displacement. The drive transmission might comprise a chain and sprocket arrangement.
Also, the X-axis sensing means might comprise a photoelectric encoder mounted to one of the gantry or a carriage of the track and carriage means. The photoelectric encoder is preferably aimed at a strip on the tabletop, or otherwise somewhere else with the table. The stip will include photoelectric graduations allowing the photoelectric encoder to generate signals corresponding to X-axis displacement of the gantry. Such photoelectric graduations might be a marking stripe having dark and light alternations, or else a series of uniform notches, and so on.
An inventive aspect relates to the processing circuitry being configured with communication paths and ports sufficient for accessing pre-programmed profiles or instruction sets from storage in or on any of the following:—ie., chip memory, a hard disk, a floppy disk, a CD, or from alternative other remote devices accessible through either network- or modem-interfaces. That way, the profiles or instruction sets can be downloaded from a link through an intranet or the internet, and so on.
Another aspect of the invention is if it further includes a manual command means. The manual command means not only operating the machine in a manual mode, but also programming or entering profiles for storage and retrieval by the equivalent of a RECORD mode. Thus the manual command means, more particularly, is provided for electrically controlling the gantry moving means, the pressing-unit moving means and the actuating means. It includes a manually-operated control having electrical outputs and signal delivery means for delivering signals at said outputs representative of movement of said manual control corresponding to desired X and Y directions of movement of the gantry and pressing unit, responsive means for responding to said signals for driving said gantry moving means and pressing unit moving means, and a switch for actuating the actuating means.
The processing circuitry is linked to the manual
Bay Jonathan A.
Gerrity Stephen F.
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