US3178525A

US3178525A - Timing belt operated switches and switch mechanism

Info

Publication number: US3178525A
Application number: US144874A
Authority: US
Inventors: Thomas R Smith
Original assignee: Maytag Corp
Current assignee: Maytag Corp
Priority date: 1961-10-13
Filing date: 1961-10-13
Publication date: 1965-04-13
Anticipated expiration: 1982-04-13
Also published as: GB1010305A; SE306573B; DE1540677A1

Description

April 13, 1965 T. R. SMITH TIMING BELT OPERATED SWITCHES AND SWITCH MECHANISM Filed Oct. 13. 1961 3 Sheets-Sheet l AGENT April 13, 1965 T. R. SMITH 3,178,525

TIMING BELT OPERATED SWITCHES AND SWITCH MECHANISM Filed Oct. 15. 1961 3 Sheets-Sheet 2 INV EN TOR.

AGENT April 13, 1965 T. R. SMITH 3,173,525

TIMING BELT OPERATED SWITCHES AND SWITCH MECHANISM Filed Oct. 15. 1961 3 Sheets-Sheet I5 64/5 76 (i9 INVENTOR.

Tho/7242555772652, BY

AGENT United States Patent 3,178,525 TIMING BELT OPERATED SWITCHES AND SWITCH MECHANISM Thomas R. Smith, Newton, Iowa, assignor to The Maytag Company, Newton, Iowa, a corporation of Delaware Filed Oct. 13, 1961, Ser. No. 144,874 Claims. (Cl. 200-38) This invention relates as indicated to timing mechanisms, and more particularly to timing mechanisms for controlling switching devices so as to obtain timed sequential operations.

In the most widely used timing mechanisms disc cams are mounted on a shaft driven by a timing motor. The disc cams operate electrical switches for controlling the time and sequence of a program of operations. The size of the discs limits the amount, and number, of operations which may be controlled. In addition, if several operations are simultaneously initiated by separate cam discs, these discs must be lined up accurately, relative to each other, on the shaft, which is both laborious and expensive. Funrthermore, if the sequence of operations is to be changed, the cam discs must be replaced, or adjusted, and a skilled mechanic is needed to make the correct alignments.

It is, therefore, an object of the invention to provide a timing mechanism by which a large number of opera tions may be controlled. It is a further object of the invention to provide a compact timing mechanism, even though it controls a large number of switches. It is yet a further object of the invention to provide a timing mechanism which performs or controls a sequence of operations, and simultaneous operations, more accurately than attainable by conventional devices. It is another object of the invention to provide a timing mechanism by which positive action of electrical switching devices is achieved. It is still another object of the invention to provide a timing mechanism in which the entire program may be replaced with another by unskilled persons. It is yet another ob ject of the invention to provide a timing mechanism by which the operation may readily change to different positions of the programmed cycle. It is still yet another object of the invention to provide a timing mechanism which is adaptable to use of indicating systems showing the positions of the programmed cycle in operation. It is a still further object of the invention to provide a timing mechanism which may be easily inspected and repaired. Further objects of the invention will become evident as the description proceeds and from an examination of the accompanying drawings which illustrate several embodiments of the invention and in which similar numerals refer to similar parts throughout the several views.

In the drawings:

FIGURE 1 is a side view in elevation of a timing mechanism embodying the invention;

FIGURE 2 is a bottom view of the timing mechanism of FIGURE 1;

FIGURE 3 is an enlarged view of the switches employed in the timing mechanism of the invention;

FIGURE 4 is an enlarged view in section of the transmission mechanism for obtaining high and low speeds in the timing mechanism;

FIGURE 5 is a sectional view taken substantially along the lines 55 of FIGURE 4;

FIGURE 6 is a sectional view taken substantially along the lines 66 of FIGURE 4;

FIGURE 7 is a diagrammatic perspective view of the transmission mechanism of the invention operating at low speeds;

FIGURE 8 is a diagrammatic perspective view of the transmission mechanism when it is shifted in preparing to operate at high speeds;

3,178,525 Patented Apr. 13, 1965 "ice FIGURE 9 is a diagrammatic perspective view of the transmission mechanism when it is shifted in preparing to operate at high speeds;

FIGURE 10 is a diagrammatic perspective view of the transmission mechanism after it is shifted and when it is operating at high speeds; and

FIGURE 11 is a fragmentary view in side elevation of a modified form of transmission which may be used in the invention.

Referring now to FIGURES 1 and 2 of the drawing, a timing mechanism 1d is illustrated having a frame 11. An endless belt 12 is movably supported

betwen rollers

14, 15, 16 and drum 17 journalled on the frame. The drum 17 is driven by motor 20 through transmission 21. Motor 20 drives the transmission 21 through motor shaft 22. Transmission 21 drives drum 17 through shaft 18.

Transmission 21 drives the drum shaft 18 at a slow timing sped, and at high rapid advance speeds. The slow timing speed is used to advance the endless belt 12 in timed sequential positions of operations. The high speed is used to rapid advance the endless belt during switching operations, or to select a desired position in the cycle, as more fully described hereinafter.

Transversely across the endless belt 12 is mounted cross piece 24 on frame 11. Supported on the cross piece, adjacent the endless belt, are a number of switches, for example, switches 30, 30'.

Referring now to FIGURE 3, there is shown an enlarged view of

switches

30, 30, in cross section and elevation, respectively.

Switches

30 and 30 are mounted on cross piece 24. The following description is concerned with switch 30, although the other switches are similarly constructed.

Switch 30 has

terminals

31, 32 to which may be attached the leads to the device to be controlled.

Terminals

31, 32 are adapted to receive removable fittings for the leads (not shown), so that they may be readily taken off, if it is necessary to replace the entire bank of switches on cross piece 24. The switches mounted on the cross piece 24 may be quickly inspected and repaired by removal of cross piece 24 from the frame 11, without detaching the leads from the terminals.

The

terminals

31, 32 are connected electrically to contacts 33, 34, respectively. Bridging contacts 33, 34 is a switch blade 36 having

contacts

37, 38 normally engaging contacts 33, 34 so that there is electrical continuity between

terminals

31 and 32. The switch blade 36 is biased by spring 39 mounted within a housing 40 so that

contacts

37, 38 are held against contacts 33, 34. Depending from the switch blade 36 is a cam follower 44, having an inclined bottom edge 45. The cam follower 44 is adapted to project through opening 46 in the endless belt 12. When the belt is moved from right to left, as shown in FIGURE 3, edge 45 of the cam follower 44 will be contacted by belt 12 at the end of opening 46 which acts as a cam. As the belt continues its movement and cam action, the cam follower 44 will raise the switch blade 36, as illustrated by the position of the switch blade 36 of switch 31). When the switch blade 36 is lifted by the coaction of the belt 12 against the cam follower 44, contact 37, or 38, or both, are lifted from engagement with the contacts 33, 34 to break the electrical connection between

terminals

31, 32. As shown by the switch 30, the switch blade 36' has rocked, or rotated, about contact 38 so as to lift and separate the contact 37' from contact 33' to break the electrical connection between the terminals 31' and 32'.

As best shown in FIGURE 1, openings, or slots, 46 are formed in the endless belt 12 at preselected locations to cause the desired sequential cycle of operation by actuation of the various switches, such as 30 and 30 at the proper time. The switches may be mounted at spaced transverse positions, to be operated by openings 46 formed in belt 12 along a longitudinal path.

It will be apparent that various modifications to the belt may be made. For example, rather than slots in belt 12, ridges, or rises, on the belt may be used to operate the cam followers 44, in order to achieve the same results.

Referring now to FIGURES 4 through 6, the transmission 21 for driving the belt at low and high speeds will be described. Transmission 21 is driven by a worm 50 mounted on motor shaft 22. The worm 50 drives gear 51 mounted on carrier 52. Carrier 52 is secured to the frame 11. Gear 51 rotates a pinion gear 53, which is mounted between ring gear 55 and gear 56. Gear 56 is locked, or splined, to sun gear 61 through hub 62 so that sun gear 61 is rotated in unison with, and by, gear 56. A housing 64 on the outside of the transmission contains a second ring gear 65 integral thereto, and on the internal periphery thereof. Secured to the edge of the housing 64 is a spiral spring 67 which engages the periphery of ring gear 55 in a clutch action. The engagement between spring 67 and ring gear 55 produces a friction coupling between ring gears 55 and 65. Planet gears 76, 71 are secured to carrier 73 and coact with sun gear 61 and ring gear 65. The carrier 73 is keyed to shaft 18. The shaft 18, however, is journalled in sun gear 61, gear 56, and carrier 52.

As best shown in FIGURES 2, 4, and 7 through 11, on the outer surface of the housing 64 is mounted a spring biased arm 75 pivoted at 76 on a pin secured to the housing 64. The arm 75 at its outer end has a finger 78 which is normally withdrawn from the periphery of housing 64 by spring 7%. In this condition transmission 21 rotates shaft 18 at a slow rate of speed. However, when the arm 75 is pivoted about 76 against spring 79, finger 78 projects or extends away from the periphery of housing 64 so that it engages stop or abutment 81 on frame 11. In this condition transmission 21 rotates shaft 18 at a high rate of speed.

The gear train comprised of Worm 56 driving gear 51, pinion gear 53, gear 56 and sun gear 61 presents the sun gear 61 teeth to

planet gear

70, 71 at a particular rate of speed. Ring gear 65 is reacted upon by

planet gears

76, 71. The rate of revolution of ring gear 65 is limited by the clutch action of spring 67 between ring gear 65 and ring gear 55. Ring gear 55 is restrained to a fixed speed by tooth contact with pinion gear 53. The planet gears 76, 71 walk around, with respect to carrier 52, because of the speeds and directions of sun gear 61 and ring gear 65. Since the planet gears 76, 71 are mounted on carrier 73 which is fixed to shaft 18, the shaft 18 is driven at a slow timing speed in the direction indicated by the arrow in FIGURE 6.

When the ring gear 65 is held by the engagement of finger 78 with the stop 81, the planet gears 70, 71 are driven by the sun gear 61 to rotate carrier 73 and shaft 18 at a high speed. When housing 64 is held, spring 67 slips relative to ring gear 55. The ring gear 55 then idles. The drive for shaft 18 is through worm gear 50, pinion gear 51, gear 56, sun gear 61, reacting with planet gears 70, 71 which in turn react with ring gear 65 mounted on carrier 73, which drives shaft 18 at high speed because of the gear ratio in this gear train.

It will be seen that the endless belt 12 may be advanced by the transmission 21 at slow and high speeds. The slow speed is used to time the sequential operations of the switches 30. The high speed is used to advance the belt for operation of the switches 30. Thus, when switches 30 are to be opened the belt 12 is rapidly advanced for an interval concurring with the operation of the switch so that the switching takes place rapidly. The timing belt is normally advanced at slow timing speeds but is rapidly advanced in connection with and during the period of the switching operations of switches 36. In addition, the rapid advance mechanism may be used to locate the timing at a desired point in the cycle.

As best shown in FIGURES l, 2 and 7 through 11 the transmission is actuated to high speeds by trigger lever 83 pivotally supported on bracket 84 on frame 11.

The trigger lever 83 has on one end a finger 86 which engages the bottom surface of belt 12. The finger 86 is biased into engagement with the belt 12 by snring 87. The opposite end of trigger lever 83 is provided with the second finger 89 normally spaced away from the arm on housing 64.

Openings or slots 91 are formed in the belt 12 at 10- cations which correspond to periods of time at which the belt 12 is to be rapidly advanced at high speeds. When the finger 86 enters anopening'Ql, as shown in FIGURES 9 through 11, the trigger lever 83 is pivoted so that finger 89 moves toward the housing 64 and engages arm 75. When finger 89 engages and pivots arm 75 during the rotation of housing 64, through spring coupling 67 against ring gear 55 (FIGURE 4), finger 78 is extended so it engages the stop 81. When the finger 78 engages stop 81, housing 64 and ring gear 65 are held against rotation so as to allow ring gear 55 to slip relative to spring 67, with the result that shaft 18 and endless belt 12 are rapidly advanced at high speeds. After the period of time determined by the length of slot 91, the lever 83 is returned to the normal position against spring 87 and transmission 21 again rotates the belt at a slow timing speed.

FIGURE 11 shows a modified form of transmission in which two levers 75 and 75' are pivotally mounted on the face of the housing 64 by employing two levers similar to 75. A morerapid response to the actuation of lever 83 is obtained by the use of two levers 75 and 75'.

It may he sometimes desirable to position the belt 12 at a desired operation in the cycle. This may be accomplished by manually depressing the plunger 160. Plunger is movably mounted on brackets 101, 102 secured to frame 11. The end 164 of plunger 100 is adjacent the face of housing 64 and is normally biased away therefrom by spring 165. When the plunger 106 is manually depressed, end 164 assumes a position in the path of the end of lever 75 so as to hold the ring gear 65 against rotation. As explained hereinabove, holding the housing 64 and ring gear 65 against rotation causes rapid advance of shaft 18. When the plunger 100 is released the lever 75 is disengaged, with the result that shaft 18 again rotates at a slow timing speed.

The return spring 165 is mounted between bracket 102 and abutment 166 on plunger 100. The abutment 106 has an outer surface which acts as a cam to disconnect the power to the switches, for example, 36, 30', during the time the belt is advanced at high speeds.

Switch 110 is in electrical series with the power for both the motor 20 and switches, for example, 30, 30. When the plunger 100 is in normal position the button of switch 110 is engaged by abutment 106 on plunger 166 to supply power to the motor and switches. However, when plunger 166 is depressed the abutment 106 is disengaged from switch button 115 so that the power to the motor and switches is disconnected.

Switch 112 is in series with an alternate power supply to motor 20. The alternate power supply through switch 112 is parallel to the power supply to motor 20 through switch 110. When the plunger 100 is depressed the abutment 106 engages switch button 116 of switch 112 so that motor is energized, but the switches remain deenergized. The result obtained by manually depressing plunger 100 then is to rapid advance the belt 12, and at the same time disconnect the power supply to the switches.

From the foregoing it is believed that operation of the timing mechanism of the invention is apparent. Switches such as 30, 30', adapted to control the various operations of a programmed cycle, are transversely spaced across the face of the belt 12. The belt is provided with suitable cam formations for operating the preselected switches at predetermined times so as to obtain the desired sequence and time of operation. During the period concurring with the operation of the switches, transmission 21 advances the belt at high speeds, after which the belt is returned to normal slow timing speed. The rapid advance is preset to occur at the proper intervals by openings or slots 91 in the belt which operate a lever 83 to control the transmission 21.

The belt 12 may be rapid advanced by manual depression of the plunger 100. As long as the plunger 100 is depressed the belt 12 will be advanced at high speeds. Thus, a separate manually operable device may be used to selectively advance the belt to desired poistions.

It will be seen that the. belt 12 may be of various lengths to control a large number of switching devices, or to control a large number of operations. The belt may be folded back and forth within the frame 11, as between

rollers

14, 15 and 16, to keep the mechanism compact.

By rapid advancing the belt during the switching operation several unique advantages are achieved. The problem of electrical arcing between switch contacts as they are opened and closed is reduced if it is performed quickly. Further, if a number of switches are to be operated at the same time, the rapid advance improves the accuracy of their simultaneous operation, so that if the slots 46 are not exactly aligned, the rapid advance minimizes the diiference. Still further, the rapid advance assures positive action in operation of the switches.

If it is desired to change the programmed cycle of operation it is only necessary to substitute another belt. To change the sequence of operations the new substituted belt is formed with the cam openings 46 at different selected locations.

The belt 12 is adaptable to the printing of legends indicating the cycle of operation being controlled by the switches. The relatively long length of the belt 12 provides adequate space for containing information regarding the various operatimls.

Another advantage of the invention is the facility by which the switches, for example, 30, may be inspected and repaired. The entire cross piece 24 may be readily removed from the frame 11 without disconnecting the leads (not shown) on the terminals.

In the drawings and specification there have been set forth several embodiments of the invention, and although specific terms are employed, these are used in a generic and descriptive sense only, and not for purposes of limitation. Changes in form and proportion of parts, as well as the substitution of equivalents are contemplated, as circumstances may suggest or render expedient, without departing from the spirit or scope of this invention as further defined in the following claims.

I claim:

1. A timer comprising, a plurality of controlled devices for controlling the cycle of a machine, cam means for operating said controlled devices, means for advancing said cam means at a timing speed to cause a timed sequence of operations of said controlled devices, alternate means for advancing said cam means at a high speed relative to said timing speed, and means for actuating said alternate means for short time intervals concurring with the operation of at least one of said controlled devices during said timed sequence.

2. In a timer the combination comprising, a plurality of controlled devices, cam means associated with an endless belt for operating said controlled devices, means for advancing said cam means at a timing speed to cause a timed sequence of operations of said controlled devices, alternate means for advancing said cam means at a high speed relative to said timing speed, and means for actuating said alternate means to advance said cam means at high speeds through the periods of operation of at least one of said controlled devices and for deactuating said alternate means after operation of said controlled devices in order that said cam means is returned to timing speed.

3. A timer comprising, a plurality of controlled devices, cam means for operating said controlled devices, means for advancing said cam means at a timing speed to cause a timed sequence of operations of said controlled devices, alternate means for advancing said cam means at a high speed relative to said timing speed, and means for actuating said alternate means to interrupt said timing speed during at least the period of operation of at least one of said controlled devices.

4. A timer comprising, a movable belt, electrical switch ing devices, means on said belt for operating said switch ing devices, motor means for driving said belt through sequential positions to obtain a timed sequence of operations of said switching devices, rapid advance means for advancing said belt at high speeds, and means cooperable between said belt and said rapid advance means for intermittently advancing said belt at high speeds through the period in said timed sequence during which at least one of said switching devices is operated.

5. In a program timer, an endless belt, motor means for driving said belt at a slow timing speed, rapid advance means for advancing said belt at high speeds, electrical switching devices, means associated with said belt for actuating said electrical switching devices to control a pro grammed sequence of operations, and means controlling said rapid advance means for advancing said belt at high speeds intermittently in connection with and during the period of actuation of at least one of said electrical switching devices.

6. A timer comprising, an endless belt, electrical switching devices, means on said belt for operating said switching devices, means for driving said belt through sequential positions at a timing speed to obtain a sequence of operations of said switching devices, rapid advance means for advancing said belt at high speeds greater than said timing speed, and means cooperable between said belt and said rapid advance means to interrupt said timing speed for advancing said belt at high speeds through the period at least one of said switching devices is operated.

7. A timer comprising, switching devices, cam means for operating said switching devices, means for advancing said cam means through sequential positions to obtain a timed sequence of operations of said switching devices, rapid advance means for advancing said cam means at speeds higher than said timed sequence, means controlled by said cam means for actuating said rapid advance means at intervals during said timed sequence concurring with the operation of at least one of said switching devices, and manually operable means for actuating said rapid advance means to select a desired position in the sequence of operations.

8. A timer comprising, electrical switching devices, cam means for operating said electrical switching devices, drive means for advancing said cam means at a timing speed through sequential positions to obtain a timed sequence of operations of said electrical switching devices, rapid advance means for advancing said cam means at high speeds, means for actuating said rapid advance means during said timed sequence for rapidly operating at least one of said electrical switching devices, manually operable means for actuating said rapid advance means to select a desired starting position in the sequence of operations, and means for disconnecting the power supply to said electrical switching devices when said manually operable means is operated.

9. In a timer having cams and switching devices operated by said cams and means for advancing said cams at a first timing speed and at a second rapid advancing speed, the combination of means for actuating said advancing means at said second speed to a start position in a programmed sequence of operation of at least one of said switching devices, means for actuating said advancing means at said first speed during said programmed sequence, and means for actuating said advancing means at said second speed during said programmed sequence for operating the switching devices whereby switching 7 is accomplished at a relatively high speed and the programmed sequence is at a lower timing speed.

10. The combination set forth in claim 9 in which said switching devices comprise electrical switching devices and in which said means for actuating said advancing means at said second speed to a start position is manually operable and the combination further including means for disconnecting the power supply to said electrical switching devices when said actuating means is manually operated.

References Cited by the Examiner UNITED STATES PATENTS Lyman 20033 Beglund ZOO-61.18 Lehde 20033 Frye ZOO--33 Sisson 20038 Freedman et al. 200-38 10 BERNARD A. GILHEANY, Primafy Examiner.

Claims

1. A TIMER COMPRISING, A PLURALITY OF CONTROLLED DEVICES FOR CONTROLLING THE CYCLE OF A MACHINE, CAM MEANS FOR OPERATING SAID CONTROLLED DEVICES, MEANS FOR ADVANCING SAID CAM MEANS AT A TIMING SPACED TO CAUSE A TIMED SEQUENCE OF OPERATIONS OF SAID CONTROLLED DEVICES, ALTERNATE MEANS FOR ADVANCING SAID CAM MEANS AT A HIGHT SPEED RELATIVE TO SAID TIMING SPEED, AND MEANS FOR ACTUATING SAID ALTERNATE MEANS FOR SHORT TIME INTERVALS CONCURRING WITH THE OPERATION OF AT LEAST ONE OF SAID CONTROLLED DEVICES DURING SAID TIMED SEQUENCE.