This is a divisional of copending Canadian Patent Application Serial No. 357,124 filed on July ~8, 1980.
The field of the invention is computer terminal equipment, and particularly, display terminals suitable for industrial applications.
Computer terminals are commercially available in a wide variety of configurations. The most common configuration includes a cathode ray tube display (CRT) and a keyboard which may either be attached to the display or contained in a separate housing that is electrically connected to the display.
Such CRT terminals also include one or more serial communications ports which may be connected to a similar port on another piece of equipment such as a computer, process controller, or programmable controller.
Although the CRT display is very general purpose~ the same cannot be said of the keyboard. For many commercial applications a typewriter key-board is appropriate, but there are many instances in industrial applications where special purpose mnemonics, symbols or fonts are used and in which a standard alpha-numeric keyboard becomes awkward. One such application, for example, is the input of control program data in~o a programmable controller.
Our copending Canadian patent application Serial No. 360,324 filed on September 16, 1980 and entitled "Industrial Terminal" describes circuitry for a multi-purpose terminal. Circuitry for driving the CRT display and receiving data at serial I/O ports is provided on a main circuit board.
This portion of the circuitry is very general purpose in nature and separate circuitry for "tailoring" the terminal to a specific application is provided on a separate application module. The application module also includes the data entry apparatus peculiar to that application, which in most in-stances is a keyboard with suitable symbols.
According to the present invention, there is provlded a terminal for housing electronic circuitry and a cathode ray tube display, the com-bination comprising; a bezel which defines an opening through which the cathode ray tube is viewed and which has an outer periphery that completely encircles said opening; back means spaced from the bezel to define a cavity between them in which the cathode ray tube and electronic circuitry are con-li 1 ~193~
tained, said back means having an owter periphery; cover means which extends between the bezel and the back means and which encloses the cavity there between; a forward bumper formed of a resilient material, said forward bumper being fastened to said bezel and being positioned to extend complete-ly around its periphery; and a rear bumper formed o-f a resilient material, said rear bumper being fastened to said back means and being positioned to extend completely around its periphery, wherein the forward and rear bumpers provide resilien~ support for the terminal which spaces the cover means from a surface upon which the terminal may rest. The bumpers provide resilient support regardless of the orientation of the terminal when it is set down on a surface and they provide attractive accent lines.
The present invention and that of copending application Serial No. 357,124 will now be described in greater detail with reference to the accompanying drawings, in which:
Figure 1 is a perspective view of the preferred embodiment of the invented terminal, Figure 2 is a side elevation view of the terminal of Figure 1, Figure 3 is an exploded perspective view of the terminal of Figure 1, Figure 4 is a front elevation view of the main unit which forms part of the terminal of Figure 1, Figure 5 is a rear elevation view of the application module which forms part of the terminal of Figure 1, Figure 6 is a partial top view of the terminal of Figure 1 with parts cut away to show the connection of the application module to the main unit, Figure 7 is a view in cross section taken on the plane 7-7 in-dicated in Figure 6, Figure 8 is a view in cross section taken along the plane 8-8 indicated in Figure 6, Figure 9 is a view in cross section taken along the plane 9-9 indicated in Figure 6, 6 ~ 9 3 7 Fig. 10 is a view in cross section taken through a for~ard bumper which forms part of the terminal of Fig 1, and Fig. 11 is a top view of an al~ernative application module which may be used on the terminal of Fig. 1.
Referring particularly to Figs. 1-3, the preferred embodi-ment of the invention is a terminal intended for industrial use which includes a substantially rectangular main unit 1 and an application module 2 which connects to the front of the main unit 1. The main unit 1 is constructed around a wire frame, or chassis (not shown in the drawings) to which a two-part molded plastic bezel 3 and a molded plastic back 4 connect to form the front and back of the main unit 1. A sheet metal top cover 5 fastens to the wire frame to not only enclose the top surface of the main unit 1, but also, to extend downward to form the upper portion 5A of the left and right sides of the main unit l. Similarly, a sheet metal lower cover 6 encloses the bottom of the main unit 1 and it extends upward along each side to form the lower portion 6A of the left and right sides of the main unit 1. At the juncture of the covers 5 and 6 on the right hand side of the main unit 1 is a handle 7 which is securely fastened to the chassis. The bezel 3, the back 4 and the covers 5 and 6 thus substantially enclose the electronic circuitry in the main unit 1 to protect it from the harsh industrial environment and the handle 7 provides a convenient means for carrying the term-inal from one application to the next.
Referring particularly to Figs. 3-5, the bezel 3 provides a large rectangular opening 9 in its surface through which a cathode ray tube screen 10 can be viewed. Alongside the open~
ing 9 is a much smaller opening through which the shaft of an intensity control (not shown in the drawinys) extends. A knob 11 is attached to ~his shaft and it can be easily adjus-ted by 1:~63~37 the user to control the brightness of the display 10. ~elow these openings is a large openiny 12 which is located along the bottom edge of the bezel 3 and which exterlds completely across its width. The opening 12 is in the sarne plane as a main cir-cuit board 13 which is contained within the main unit 1 andwhich mounts the electronics for the main unit 1. A pair of electrical connectors 14 and 15 fasten to the main circuit board 13 and these face outward through the opening 12 to con-nect with mating connectors 16 and 17 in the application module
2. All electrical connections between the main unit 1 and the application module 2 are made through the connectors 14-17.
Alignment of the application module 2 within khe opening 12 is provided by a pair of circular cylindrical guideways 19 and 20. As shown best in Figs. 4, 6 and 8, the guideways 19 and 20 are molded as an integral part of the bezel 3 and are located at the lefthand and righthand extremities of the open-ing 12. The guideways 19 and 20 are aligned along parallel longitudinal axes and they are spaced apart to receive mating guideposts 21 and 22 that are mounted on the application module 2. The molded bosses 23 and 24 which define the guideways 19 and 20 have considerable mass and considerable axial leng-th to not only align the application module 2, but to also provide support for the application module 2 by transmitting bending forces to the frame of the main unit 1. The guideways 19 and 20 may be tapered in the axial direction to ease insertion of the guideposts 21 and 22 and shapes other than circular cylin-drical may also be employed with equal success.
As shown best in Figs. 3 and 5-9, the application module 2 includes a molded plastic housing 25 which is shaped to form a bottom 26, verticle left and right sidewalls 27 and 28, an up-turned front wall 29, and a separate top 30. Slots 31 are -- 'I --~ g3~ ~
formed along the front wall 29 to allow the free flow of cool~
ing air to the circuitry inside the module 2 and a cavity 32 is formed in the front wall 29 by a recess which is located at its middle. Thxee hinge posts 33 are formed along the back edge of the top 30 and these receive three corresponding sets of fingers 34 which are integrally molded to a keyboard retainer frame 35.
The frame 35 is rectangular in shape and it has a large window 36 which lays over the top 30 of the module housing 25 when the retainer frame is swung downward into an operating position. A
pair of clasps 37 and 38 are formed on the outer edge of the keyboard retainer frame 35 and these snap into slots 39 and 40 formed in the top 30 to hold the frame 35 in place.
As shown best in Figs. 3, 7 and 9, the top 30 of the module housing 25 is recessed slightly over its middle portion to receive a flexible membrane keyboard. The keyboard includes a five by fourteen switch matrix 42 and a keyboard overlay 43.
The switch matrix 42 includes two ribbons 44 containing conduc-tive leads which connect to the switch matrix 42 and which ex-tend down through openings 45 in the top 30 to make connection ` 20 with a circuit board 46 mounted within the module housing 25.
As shown in Fig. 9, connection is made by a pair of connectors 47 which ~re soldered directly to the circuit board 46.
Laid loosely on top of the switch matrix 42 is the key-board overlay 43. The keyboard overlay 43 is comprised of a first sheet of flexible plastic on which symbols for the key-board are printed and a second sheet of less flexible plastic material which defines the boundaries for each key. It fits within the recess formed in the top 30 and it includes a pair of guide holes 48 which fit snuggly over corresponding guide pins 49. The guide pins 49 extend upward from the top 30 on its lefthand and righthand edges and they serve to align the keyboard overlay 43.
6 ~ 9 3 ~
It is one of the advantages of khe present invention thatthe keyboard overlay 43 can be easily changed to provide the user with a variety of keyboard key arrangements and key sym-bols. Consecluently, a par-ticular overlay 43 may define only a few keys which are aligned over a few corresponding switches in the switch matrix 42, whereas another overlay 43 may define a large number of keys. These overlays 43 may be exchanged by swinging the retainer frame 35 upward as shown in Fig. 3, re-moving one overlay 43 and replacing it with another. The re-tainer frame 35 is then swung back into its operating positionin which the overlay 43 and switch matrix 42 are sandwiched be-tween the retainer frame 35 ancl the top 30 of the module housing 25.
Referring particularly to Figs. 5 and 7, the circuit board 46 in the application module 2 is mounted such that i~ is aligned with the circuit board 13 in the main unit 1 when the application module 2 is fastened in place. The circuit board 46 is supported by four lower posts 52 which extend upward from the housing bottom 26 and four upper posts 53 which extend down~
ward from the housing top 30. Screws (not shown in the draw-ings) extend upward through the lowex posts 52 and through aligned openings in the module circuit board 46 into threaded engagement with the upper posts 53. These screws not only fasten the circuit board 46 in place, but they also fasten the housing top 30 to the remainder of the application module hous-ing. For a cletailed description of the electronic circuitry on the circuit board 46, reference is made to the above cited copendincJ application entitled "Industrial Terminal".
As shown best in Figs. 5, 6 and 8, the guide-posts 21 and 22 are fastened to bosses 55 and 56 which are integrally molded to the bottom 26 of the module housing 25. The bosses 55 and 1 9 3 i`~ ~
56 extend upward from the bottom 26 and provide flat mounking surfaces upon which the guideposts 21 and 22 are fastened. The guideposts 21 and 22 each have a slightly enlarged barrel por~
tion 21' and 22' which is flat along one side and which in-cludes a pair of threaded openings on the flat surface. Screws57 extend upward through openings in the bosses 55 and 56 and they are received in these threaded openings to tightly fasten the guideposts 21 and 22 in place.
Referring particularly to Figs. 4-7, the application module 2 is securely retained in its operating position by a fastening mechanism which includes a lever 59. The lever 59 is fastened to the bottom 26 of the application module housing 25.
A bolt 60 extends upward through an annular shaped guide 61 and into threaded engagement with a metal pivot bushing 62. The bushing 62 extends through an opening i~ the lever 59 and it has a cap 63 which holds the lever 59 in place and allows it to pivot about a vertical axis. One end of the lever 59, extends forward through a slot 64 in the housing cavity 32 where it can be manually operated by the user.
The other end of the lever 59 extends into the main unit 1 where it engages a cam plate 65 that is fastened to the bottom of the bezel 3 through a pair of integrally molded posts 66.
The operating end of the lever 59 is bifurcated to provide a pair of spaced fingers 67 which support between them a roller 68. As shown best in Fig. 6, ~Ihen the application module 2 is inserted into the main unit 1, the roller 68 on the operating end of the lever 59 enters the mouth portion 69 of a slot formed in the cam plate 65. At this point the electrical con-nectors 14-17 are in partial engagement and the guideposts 21 and 22 have properly aligned the application module 2 for com-plete engagement. ~Ihe lever 59 is then pivoted in the clock-wise direction and the roller 68 rides along a sloped cam
3 ~ f portion 70 of the slot in the cam plate 65. A force directed along an axis parallel to the guideposts 21 and 22 is thus pru duced which draws the application module 2 into complete engage-ment with the main unit 1. Considerable frictional forces can - 5 thus be overcome merely by swinging the lever 59 from one end to the other of the slot 64.
The primary us~ for the terminal is to program, edit and trouble shoot industrial e~uipment such as programmable con-trollers and process controllers. Such equipment may be located in relatively clean and centrally located data processing centers or it may be located at remote locations throughout a manufacturing plant. The terminal of the present invention is compact and relatively lightweight and it includes a handle which further facilitates its use throughout a manufacturing plant. One difficulty which has been encountered in the past with such industrial terminals is that they are not necessarily set down or used in an upright position. Instead, they may be set on their side, or even upside down.
The industrial terminal of the present invention contern-plates such use. Referring particularly to Figs. 1-3 and 10, the terminal includes a pair of elastic bumpers 75 and 76 which each extend completely around the main unit 1. The forward bumper 75 extends around the perimeter of the bezel 3 and the rear bumper 76 extends around the perimeter of the back 4. The forward and rear bumpers 75 and 76 are spaced from one another and follow substantially parallel paths around the periphery of the main unit 1. Both the bezel 3 and back 4 have an integrally molded tenon 77 which extend outward from their surfaces and around their periphery. The tenons 77 engage a mating mortise 78 which is formed on the underside of each bumper 75 and 76.
The bumpers 75 and 76 are thus securely retained in position to 1 ~ 1 9 3 ~ ~
provide resilient support on the bottom, both sides, and the top of the main unit 1.
It should be apparent to those skilled in the art that numerous variations can be made from the preferred embodiment of the invention. For example, in Fig. 11 another application module 80 is shown which functions to program read-only memory circuits for use in programmable controllers. The construction of the application module 80 is nearly identical to that de-;- scribed above except the keyboard 81 and retainer frame 82 does not extend across the entire top 86 of the module. Instead, a socket 83 for a twenty-four pin dual-in-line integrated circuit package 85 is mounted to the lefthand side of the top 86.
Commands are entered using the keyboard 81 to load a program into the memory circuit 85 plugged int.o the socket 83 as taught in U.S. Patent No. 3,798,612, issued on March 19, 1974 and en-titled "Controller Programmer". Obviously, the circuitry in the application module 80 differs considerably from that in the application module described above, since its function is to "burn" a program into a memory circuit 85. As with the module 2 described above, however, the keyboard overlay may be changed to alter the key layout or key symbols to meet the requirements of each particular application.