Dial-type timer device

Abstract: Objective: To make it impossible to change the settings on a dial-type timer except in a fixed range. Construction: Two setting rings are mounted on the perimeter of the dial in such a way that they rotate as a single entity with the said dial. Each of the rings has a single molded tooth on its outer edge. A stop protrudes from the body of the timer which is contacted by the aforementioned teeth on the setting rings mounted on the dial. When the teeth come in contact with the stop, the range of rotation of the said dial is constrained. Effects: Two setting rings are set in positions which indicate the upper and lower limits of a dial's rotation. When these rings are mounted on the perimeter of the said dial, the settings achieved by the dial can be changed only within the range between the said upper and lower limits.

Description: This invention relates to a dial-type timer. More specifically, it relates to a dial-type timer which is ideally suited for applications such as process control which require that values once set can be changed only within a limited range. Prior Art Generally speaking, when dial-type timers are used in process control, they are set to values which should be changed only within a fixed range. However, existing dial-type timers are incapable of preventing values from being set beyond the upper and lower limits of the desired range. Thus when such a dial-type timer is used for process control, the operator must pay careful attention whenever he changes a set value and note whether or not the new value falls within the fixed range of permitted values. He is, then, unable to relax. He may also mistakenly set values which exceed the aforesaid fixed range. A dial-type timer according to the preamble of claim 1 is known from GB-A-2 234 369. From DE-U-74 32 974 a dial-type timer is known having two rings angularly displaceable about the dial, each ring being provided with a grip. Timers having dials are also known from EP-A-0 185 291 and PATENT ABSTRACTS OF JAPAN, vol. 10, no. 247 (P-490) 26 August 1986 & JP-A-61 075 286. In light of the problem discussed above, the objective of this invention is to make it possible to fix an upper and lower limit for values to be set, and to prevent values which exceed these limits from being set. To achieve the objective described above, this invention is as defined in claim 1. The timer of the invention has two setting rings with a tooth on each which can be set in a position to indicate the upper and lower limit of the range of rotation of a dial. These setting rings are mounted on the perimeter of the said dial in such a way that the teeth come into contact with a stop on the timer body or its cover. In this way the rotation of the dial is constrained not to go beyond the said positions for upper and lower limits. This invention, then, makes it possible to restrict the setting of an operating time to a fixed range defined by the aforesaid upper and lower limits. In the following section, we shall give a detailed explanation of an embodiment of this invention with reference to the drawings. Figure 1 is an oblique exploded view of a dial-type timer in which this invention has been implemented. The dial-type timer 1 of this embodiment consists of timer body 2; dial 4, which is used to set the operating time for timer body 2; and setting rings 25 and 35; which are mounted on the perimeter of dial 4. These setting rings limit the range in which dial 4 can be set. Stop 36 protrudes from the upper portion of the face of dial 4 on timer body 2. This stop limits the range of rotation of dial 4 when it comes in contact with teeth 25a and 35a on setting rings 25 and 35, as described above. As can be seen in the frontal view pictured in Figure 2 (A), the perimeter of dial 4 on timer body 2 is formed into gear teeth 4a. Dial 4 has an indicator 6 and a scale along its circumference for setting the time. It also has a number of windows 7 to display the numerals for the scale, and a window 8 to display the time unit. Gear teeth 4a on the perimeter of dial 4 are used to determine the position in which setting rinds 25 and 35 are to be mounted, as discussed below. For that reason they are cut at a pitch of 1/2 the scale units for setting the time. Along the circumference of dial 4 are POWER and OUT displays 9 and 10, operating function switch 11 and operating function display window 12. Figure 2 (B) is a partial side view of the face of timer body 2. Front and rear views of setting ring 25 are shown in Figures 3 (A) and (B). This setting ring is mounted in such a way as to engage in gear teeth 4a on the perimeter of dial 4 on timer body 2. Tooth 25a, which protrudes from the perimeter of the setting ring, comes in contact with stop 36 on timer body 2. Its surface 25c makes contact with surface 36a of stop 36 on the timer body, which is shown in Figure 2 (A). In four locations on the inner periphery of setting ring 25 are teeth 25b, which engage in gear teeth 4a on the perimeter of dial 4. A front view of the second setting ring, setting ring 35, is shown in Figure 4. This setting ring is also mounted so as to engage in gear teeth 4a on the perimeter of dial 4 on timer body 2. Tooth 35a, which protrudes from the perimeter of the setting ring, comes in contact with stop 36 on timer body 2. Its surface 35c makes contact with surface 36b of stop 36 on the timer body, which is shown in Figure 2 (A). In four locations on the inner periphery of setting ring 35 are teeth 35b, which engage in gear teeth 4a on the perimeter of dial 4. In a dial-type timer constructed as described above, the range of settings is controlled by the dial through the use of setting rings 25 and 35. When dial 4 is set in the position corresponding to the lower limit of the allowable values, surface 35c of tooth 35a on setting ring 35 comes in contact with surface 36b of stop 36 on timer body 2. Setting ring 35 engages with the perimeter of dial 4. When dial 4 is set in the position corresponding to the upper limit of the allowable values, surface 25c of tooth 25a on setting ring 25 comes in contact with surface 36a of stop 36 on timer body 2. Setting ring 25 then engages with the perimeter of dial 4. These situations are illustrated in the frontal view shown in Figure 5 (A) and the partial side view in Figure 5 (B). Thus dial 4 and setting rings 25 and 35 rotate as a single entity, and the setting on dial 4 can be changed only within the range between tooth 25a on setting ring 25 and tooth 35a on setting ring 35. The operator is prevented from setting any value outside of that range. For stop 36, which protrudes from the surface of the face of timer body 2, a lock generally found in existing timers can be used. This lock protrudes from the upper portion of the face of the timer. It is used to determine the reset position of the setting ring so that it can be reset easily when a standard operating time is being set repeatedly. This lock can be used for both purposes in the new timer. Figure 6 is an exploded oblique view of another dial-type timer in which this invention has been implemented. Components which correspond to those of the preceding embodiment have been given the same numbering. The dial-type timer 1 0 of this embodiment consists of timer body 2 0 ; cover 3, which can be mounted on tne face of the aforesaid timer body 2 0 ; and setting rings 25 and 35, which are mounted on the perimeter of dial 4 on timer body 2 0 when the aforesaid cover 3 is mounted on timer body 2 0 . Unlike the previous embodiment, this timer does not have a stop 36 protruding from the upper portion of dial 4 on timer body 2 0 . Cover 3 is already mounted on the face of timer body 2 0 when setting rings 25 and 35 are used. The cover has a round opening 13 for dial 4, and two small openings 14 and 15 for displays 9 and 10 on timer body 2 0 . Openings 13 through 15 are the only windows in cover 3. When this cover is mounted on the face of timer body 2 0 , operating function switch 11 and the other setting switches are completely enclosed. With the cover in place, there is no possibility that anyone will operate these switches mistakenly. Stop 37 protrudes from the surface of cover 3 in a location corresponding to the upper face of the aforesaid timer body 2 0 , as shown in Figure 7 (A), a frontal view, and 7 (B), a cross section of the side. Stop 37 limits the range of rotation of dial 4 when it is contacted by teeth 25a and 35a on setting rings 25 and 35. Surface 25c of tooth 25a on setting ring 25 comes in contact with surface 37a of stop 37. Surface 35c of tooth 35a on setting ring 35 comes in contact with surface 37b of stop 37. To mount cover 3 on the face of timer body 2 0 , tabs 3b on the inner surface of cover 3 (shown in Figure 7 (B)) are inserted into slots 2a on timer body 2 0 (shown in Figure 6). When cover 3 is mounted on the face of timer body 2 0 , dial 4 projects out the front of opening 13 in that cover, and setting rings 25 and 35, which engage with the outer edge 4a of dial 4, are disposed exactly as in the previous example. In dial-type timer 1 0 , which is constructed as described above, the range of settings is controlled by the dial through the use of setting rings 25 and 35. First, cover 3 is mounted on the face of timer body 2 0 . Dial 4 is set in the position corresponding to the lower limit of the allowable values, and surface 35c of tooth 35a or. setting ring 35 comes in contact with surface 37b of stop 37 on cover 3. Setting ring 35 engages with the perimeter of dial 4. Dial 4 is then set in the position corresponding to the upper limit of the allowable values, causing surface 25c of tooth 25a on setting ring 25 to come in contact with surface 37a of stop 37 on timer body 2 0 . Setting ring 25 then engages with the perimeter of dial 4. This process is illustrated in the frontal view shown in Figure 8 (A) and the partial side view in Figure 8 (B). Thus dial 4 and setting rings 25 and 35 rotate as a single entity, and the setting on dial 4 can be changed only within the range between tooth 25a on setting ring 25 and tooth 35a on setting ring 35. The operator is prevented from setting any value outside of that range, just as in the previous example. In this embodiment, the materials used for cover 3 and setting rings 25 and 35 are available in a variety of colors, so they can be chosen to match the color of the panel on which timer body 2 0 is mounted. This ensures an esthetically pleasing result. The invention described above has two setting rings, each of which has a single tooth, which Set the upper and lower limits of the rotation of a dial. These setting rings are mounted in such a way that their teeth come in contact with a stop which protrudes either from the timer itself or from its cover. In this way the rotation of the dial is stopped at the locations corresponding to the upper and lower limits. Thus the values of the settings can be changed only within the range defined by the said upper and lower limits. The operator is free to alter the settings without worry. The second embodiment of this invention has a cover mounted on the face of the timer. This cover encloses and protects the various setting switches which might cause problems if operated by mistake.

Claims: A dial-type timer comprising: a timer body (2), a dial (4) provided on the front of the timer body to set the operating time; two setting rings (35, 25) mounted on the perimeter of said dial in such a way that they rotate as a single piece with the dial (4); characterized by a molded tooth (35a, 25a) formed on the perimeter of each of said setting rings (35, 25) and facing outward; and a stop means (36; 37, 3) provided on said timer body (2) arranged to come into contact with said teeth (35a, 25a) so as to limit the range of rotation of said dial (4), said stop (36) inhibiting the dial (4) to rotate counterclockwise after contacting the tooth (35a) of one (35) of said two rings and inhibiting the dial (4) to rotate clockwise after contacting the tooth (25a) of the other ring (25) of said two rings.

Inventors: UENO SHINTARO, YAMAMOTO HIROYUKI, UENO, SHINTARO, YAMAMOTO, HIROYUKI, Ueno, Shintaro, c/o OMRON CORPORATION, YAMAMOTO, HIROYUKI, C/O OMRON CORPORATION
Applicants: OMRON TATEISI ELECTRONICS CO, OMRON CORPORATION
Application year: 1992
Main classification: G04F3
IPC codes: G04F3