US3832971A

US3832971A - Channel number display device

Info

Publication number: US3832971A
Application number: US00381988A
Authority: US
Inventors: H Yanagawa
Original assignee: Alps Electric Co Ltd
Current assignee: Alps Alpine Co Ltd
Priority date: 1972-09-18
Filing date: 1973-07-23
Publication date: 1974-09-03
Anticipated expiration: 1991-09-03

Abstract

A channel number display device for use in a television tuner or the like includes a cylindrical display drum having printed on the periphery thereof a series of helically arranged channel numbers, means operably connected to the channel selector shaft of the tuner for rotating and axially displacing the drum in response to the rotation of the selector shaft such that the appropriate number is visible through a display window located in front of the display drum.

Description

United States Patent 1191 Yanagawa Sept. 3, 1974 CHANNEL NUMBER DISPLAY DEVICE [75] Inventor: Hiroshi Yanagawa, Kakuda, Japan [73] Assignee: Alps Electric Co., Ltd., Tokyo,

Japan [22] Filed: July 23, 1973 [21] Appl. No.: 381,988

[30] Foreign Application Priority Data Aug. 8, 1972 Japan 47-92967 2,746,419 5/1956 Serge 334/87 X 2,834,216 5/1958 Thompson 74/89.l5 X 3,149,607 9/1964 Joseph et al. 334/87 X Primary Examiner-Paul L. Gensler 57 1 ABSTRACT Q A channel number display device for use in a television tuner or the like includes a cylindrical display v drum having printed on the periphery thereof a series of helically arranged channel numbers, means operably connected to the channel selector shaft of the tuner for rotating and axially displacing the drum in response to the rotation of the selector shaft such that the appropriate number is visible through a display window located in front of the display drum.

[56] References Cited UNITED STATES PATENTS 2 Claims, 4 Drawing Figures 1,846,411 2/1932 warren 116/129 G 2 j 4 4 4 38 55* f -/3 j 7 7 7 '2 aid/A I o 64 O o O 0 1 o o o 0 6a, 2 o 1 Q I o C 65 o O o O o PATENIEDSEP 319M 3.832.971

SHEET 10F 2 This invention relates to display devices and more particularly to a device for displaying channel numbers in a UHF television tuner.

Conventional counter type channel number display devices commonly used in UHF television tuners typically comprise two separate adjacent discs, one to display units digits and one for tens digits. The tens" disc is adapted to be driven, through a carry gear, by the rotation of the units disc. The tens disc is rotated through an angle equal to a numeral thereon for each revolution of the units disc. In such display devices, an intermittent locking mechanism such as a detent wheel is provided for each disc in order to prevent misregistration between the digits displayed by respective discs and between the digits and the display window. As a result, drawbacks such as large required drive force. high production cost, poor productivity, low accuracy of display and the like are present.

Another type of conventional channel number display device includes a film having printed thereon a series of channel numbers. The film is driven by a sprocket gear engaging the film. This type of device has the advantage of preventing misregistration between the-digits but has a short life span.

It is therefore the prime object of the present invention to provide a channel number display device which provides digital registration without the necessity for a large drive force, which can be economically produced.

lt is another object of the present invention to provide a channel number display device having the advantages of the film type display device but having a longer life span.

In accordance with the present invention, a novel channel number display device for a television tuner or the like is provided. The display device includes a cylindrical channel number display drum having printed on its periphery a series of helically arranged channel numbers. Means operably connected to the channel selector shaft of the tuner are provided for rotating and axially displacing the drum in accordance with the rotation of the selector shaft. A viewing station is located in front of the display drum to permit observation of the appropriate printed channel number.

In the first preferred embodiment, the rotating and displacing means comprises a stationary support shaft provided with a helical thread. The display drum has a center aperture formed with an interior helical groove meshing with the helical thread of the support shaft. A

rotation transfer mechanism is so constructed that it rotates the display drum in response to rotation of the channel selector shaft while permitting axial movement of the display drum by engagement of the helical thread with the helical groove.

In the second preferred form, the support shaft has a peripheral spline groove and is directly coupled to the rotation transfer mechanism to rotate in accordance with the rotation of the selector shaft. The display drum has a complementary spline geared center aperture in engagement with the spline grooves of the support shaft and a helical groove fom1ed in the outer periphery. A stationary guide roller is provided in engagement with the helical groove of the display drum such that the rotation of the support shaft causes the display drum to rotate. Axial movement is achieved as the helical groove of the drum is guided by the stationary guide roller.

To the accomplishment of the above and to such other objects as they may hereinafter appear, the present invention relates to a channel display device as defined in the appended claims and described in the specification, taken together with the accompanying drawings, wherein like numerals refer to likeparts and in which:

FIG. I is a front view of a first preferred embodiment of the channel number display device of the present invention with a cover removed;

FIG. 2 is an elevational section view of the device shown in FIG. 1;

FIG. 3 is a cross-sectional view of the device shown in FIG. 1 taken along line A-A; and

FIG. 4 is a front view of a main portion of the second preferred embodiment of the present invention.

Referring to FIGS. 1 through 3, the first preferred embodiment of the channel number display device of the present invention includes a frame 1, into which the channel selector shaft 2 of a UHF tuner (not shown) extends. A support shaft 3 is fixedly mounted on the frame 1 and has a peripheral helical thread 3a. A hollow cylindrical channel number display drum 4 has a central cylindrical portion 8 with a gear4a on the periphery thereof. A helical groove is provided on the interior of portion 8 which has the same pitch as that of the helical thread 30. The drum 4 is mounted on support shaft 3 with the groove in engagement with thread 3a. The display drum 4 has on its cylindrical outer periphery a plurality of helically arranged channel numbers. Each number represents a different channel to which the tuner may be tuned. In FIG. 1, only horizontally aligned

channel numbers

64, 54, 24 and 14 are shown. Square block 5 (shown by dotted lines) represents a display window which may be an opening formed in the frame 1 at a position in front of the drum 4 and above the channel selector shaft 2 to permit viewing of a single channel number at a time.

The channel number display device includes a rotation transfer mechanism 6 functioning to transfer the rotation of channel selector shaft 2 to gear 4a. The rotation transfer mechanism 6 comprises a disc 6a fixed to the channel shaft 2 and provided on one side with a number of small posts 6a circularly arranged with even spacing, another disc 6b provided with a number of small posts 6b circularly arranged on one side which mesh with the posts 6a of the first disc 6a so as to be driven thereby, a gear 6c mounted on a shaft to which the second disc 6b is fixed, another gear 6d engaging with the gear 6c and being driven thereby, and a gear 6e mounted on a shaft to which the second gear 6d is fixed to drive the gear 4a formed in the central portion 8 of the display drum 4. The shafts mounting the gears of the rotation transfer mechanism 6 are rotatably supported by the frame 1.

According to the arrangement described above of the first preferred embodiment, as the channel shaft 2 is rotated, the display drum 4 having the gear 4a coupled through the rotation transfer mechanism 6 to the channel shaft 2 moves in either axial direction along support shaft 3 while rotating about the support shaft 3, and one of the channel numbers printed around the display drum 4 can be viewed through the display window 5. For example, if the channel shaft 2 is rotated in the clockwise direction as shown in FIG. 2, the display drum 4 moves towards the right (as seen in the drawings) while rotating, and the channel numbers are successively displayed in the display window 5 in the ascending order. lf the channel shaft 2 is rotated in the reverse direction, display drum 4 rotates in the reverse direction and moves towards the left (as seen in the drawings). The channel numbers are then viewed successively in descending order.

FIG. 4 illustrates the second preferred embodiment of the present invention. This second embodiment employs a display drum having a central portion with a splined through aperture at its axis. Its outer periphery has a helical guide groove 4b along the turns of the helically situated channel numbers. The display drum 4 is supported by a support shaft 3 with the spline hole of the drum engaging the splined periphery 3b of the shaft 3 which is coupled through rotation transfer mechanism 6 to the channel shaft 2. As schematically shown in FIG. 4, stationary guide rollers 7, fixed to the frame 1, engage the guide groove 4b of the display drum 4.

The rotation transfer mechanism 6 of the second embodiment comprises a disc 6a fixed to the channel shaft 2 and provided on one side with a number of small posts 6a circularly arranged with even spacing, a gear 6c provided with a number of small posts 60 circularly arranged on one side which mesh with the posts 60' of the first disc 6a so as to be driven thereby, and another gear 6d mounted on the shaft 3 and meshing with the first gear 6c.

As the channel shaft 2 is rotated, the display drum 4 is rotated in response thereto through the rotation transfer mechanism 6, support shaft 3 and spline groove 31). Because the guide groove 4b is formed in the outer periphery of the drum 4 and engages the stationary guide rollers 7, the display drum 4 shifts axially as it rotates, guided by rollers 7 to provide successive display of the channel number in a display window similar to the window 5 of the first embodiment. That is, depending on the rotational direction of the channel shaft 2, the display drum 4 moves towards the left or right (as viewed in FIG. 4) while rotating forward or reversely, whereby the channel numbers are successively presented through the display window, for example, in the order of l4, and so on.

An intermittent locking mechanism, perhaps in the form of a detent arrangement, can be added to either the first or second embodiment for preventing erroneous alignment of the channel number with respect to the display window, whereby more correct registration of the channel number will result.

As described herein above, the present invention differs from the system wherein first and second digits of the channel number are displayed separately, so does not cause relative misalignment between first and second digits and needs only a provision to prevent displacement of the channel number in the rotation directions of the display drum. Thus, only one intermittent locking mechanism is needed and preferably provided in the device, resulting in the advantages of decreased operation or manipulation force, simple structure, low cost, high productivity, increased accuracy of display, long life span, and the like.

Two preferred embodiments of the present invention have been disclosed herein for purposes of illustration. It is apparent that many modifications and variations may be made upon the specific structure disclosed herein. It is intended to cover all of these variations and modifications which fall within the scope of this invention as defined by the appended claims.

I claim:

1. A channel number display device for use with a television tuner or the like having a movable channel selector shaft, the device comprising a stationary externally threaded shaft, a hollow cylindrical drum having a wall with an interior surface and a hub with a helically grooved inner surface and an outer surface, said outer surface of said hub having a spline gear thereon, said hub being rotationally mounted on said shaft such that said groove engages said thread, said drum having a plurality of helically arranged channel numbers on the periphery thereof, a rotatable drive shaft spaced from said stationary shaft and receivable within said drum, a gear mounted on said drive shaft and meshing with said spline gear, said drive shaft operably connected to the selector shaft such that said drum is rotated and axially displaced in accordance with the movement of said selector shaft, and a relatively fixed viewing station disposed opposite said drum and having window means to permit observation of only a limited portion of the periphery of said drum.

2. The device of claim 1 wherein the diameter of said gear is approximately equal to the radial distance between said hub and the inner surface of the wall of said hollow cylinder.