US3760138A

US3760138A - Control instrument for two or more switches

Info

Publication number: US3760138A
Application number: US00222203A
Authority: US
Inventors: R Reis
Original assignee: United Electric Controls Co
Current assignee: United Electric Controls Co
Priority date: 1972-01-31
Filing date: 1972-01-31
Publication date: 1973-09-18
Anticipated expiration: 1990-09-18

Abstract

A control instrument wherein there is a transmitter bar movable in response to a change in pressure, a pair of switches, arms supporting the switches with their actuating elements adjacent the transmitter bar for movement relative to each other and to the transmitter bar, cams operably associated with the respective arms for effecting displacement of the arms and hence the switches at different distances from the transmitter bar to predetermine the operation of the switches relative to each other, pointers for indicating the points of operation of the switches and limits interengageable at a terminal position to effect actuation of said switches in predetermined relation to each other.

Description

United States Patent 1191 Reis [ Sept. 18, 1973 CONTROL INSTRUMENT FOR TWO OR MORE SWITCHES [75] Inventor: Robert D. Reis, l-lingham, Mass.

[22] Filed: Jan. 31, 1972 [21] Appl. No.: 222,203

[56] References Cited UNITED STAT ES PAT E NTS 3,490,342 1/1970 Reis ..200/s1.4x 3,540,305 11/1970 Sprung ..20o/s3sx Primary Examiner-Herman J. Hohauser Assistant Examiner-William J. Smith Attorney-Robert T. Gammons et al.

[57] ABSTRACT A control instrument wherein there is a transmitter bar movable in response to a change in pressure, a pair of switches, arms supporting the switches with their actuating elements adjacent the transmitter bar for movement relative to each other and to the transmitter bar, cams operably associated with the respective arms for effecting displacement of the arms and hence the switches at different distances from the transmitter bar to predetermine the operation of the switches relative to each other, pointers for indicating the points of operation of the switches and limits interengag'eable at a terminal position to effect actuation of said switches in predetermined relation to each other.

8 Claims, 5 Drawing Figures :42; i1 Lvdkj 8| 102 7O i i r \I 100 78 I 80 l 88 PATENTED SEP1 8 I975 SHEET 1 OF CONTROL INSTRUMENT FOR TWO OR MORE SWITCHES BACKGROUND OF THE INVENTION Control instruments in which there are two or more switches arranged for operation in succession and/or in predetermined relation to each other in response to changes in pressure and temperature are shown, for example, in my U.S. Pat. Nos. 3,537,317 and 3,490,342

and in the U.S. Pat. to Machado, Nos. 3,352,987 and 3,309 ,480; The control instrument comprising the subject matter of this invention is designed to provide for greater flexibility and more precise adjustment of the operating relation of the switches to each other and, in

addition, to provide for visual indication of the predetermined positions of operation and the operational conditions of the switches at any given time.

SUMMARY I transmitter bar and to each other, and means for effect- ;ing adjustment of the switches relative to each other and to the transmitter bar to predetermine the operation of the switches in predetermined relation to each other. The transmitter bar is movable in response to a change in pressure and the switches are independently movable by cam means associated with the respective switches to effect independent displacement of the switchesrelative to the transmitter bar. A pair of pivotally supported arms pivoted for movement about a common axis support the switches adjacent the transmitter bar, the cams are supported for rotation about a common axis and there is spring means yieldably holding the arms in engagement with the respective cam surfaces. There is means for effecting the rotation of the cams independently of each other and means for limiting relative adjustment of the cams such that at said limiting position of adjustment the switches will be actuated simultaneously.

The invention will now be described in greater detail with reference to the accompanying drawings wherein: FIG. 1 is a front elevation of the control instrument with thecover removedshowing parts in elevation and parts in section;

I FIG. 2 is a section taken on the line 2- -2 of FIG. 1; FIG. 3 is a plan view taken in the direction of the lines 3-3 of FIG. 1;

FIG. 4 is a fragmentary front elevation of the switches and switch-actuating mechanism removed 'from the switch housing and showing the initial engagement of the transmitter bar; and

FIG. 5 is a corresponding view showing the final engagement of the transmitter bar.

Referring to the drawings (FIG. 1), the control in strument is mounted in a box within which is mounted a frame 12 mounting switches S1 and S2 and open front there is a recessed ledge 28 of a depth to receive a cover plate 30 adapted to be fastened in place by screw bolts 32 at its four comers. The cover plate is provided with an appropriate opening through which the instrument dial D may be seen. I

The frame 12 is mounted within the box 10 and secured to the bottom wall 24 by screw bolts 34. At the top of the frame 112 there is a boss 36 in which there is fixed a forwardlyextending pin 38, the forward end of which is supported in the upper end of a plate 40, the latter being secured to a boss 42 extending forwardly from the frame below the boss 36 and parallel thereto.

An arm 44 comprising spaced parallel flat plates 4646 (FIG. 3) is pivotally mounted at one end on the pin 38 and extends therefrom transversely of the box toward the opposite side. The switch S1 is mounted at the distal end of the arm 44 between the plates 46--46 and secured thereto by screw bolts 50 in a position such that its actuating element 52 (FIG. 4) projects downwardly therefrom. A second arm 54 of shorter length comprising spaced parallel plates 56-56 is also mounted at one end on the pin 38 so as to extend therefrom transversely toward the other side of the box and the switchS2 is mounted between the plates 56-56 andsecured thereto by screw bolts 58. The switch S2 is at a lesser radial distance from the pin 38 than is the switch S1 and its actuating element 60 projects downwardly therefrom. The two

switch actuating elements

52 and 60 are at adjacent ends of the switches.

The frame 12 has on it a forwardly projecting circular housing 62 (FIG. 2) within which there is mounted a shaft 64, the rear end of which is journaled in the back of the frame and the forward end of which is journaled in a wall'66 at the front of the housing and through which it projects. Two cam plates 68 and are rotatably mounted on the face of the plate 66 over the forwardly projecting end of the shaft 64 and are held in place by a retainer member 72 secured in place by screw bolts 74-74. The cam plate 68 contains a central opening and is mounted in a groove 69 in the wall 66. The cam plate 70 contains a central opening and ismounted on a circular disc 71 which, in turn, is mounted in concentric relation to the wall 66 between the wall and the retainer member 72. Friction reducing spacers 73 are mounted between the cam plates and between the member 72 and the cam plate 71. The cam plates are thus free to turn on the shaft 64. The cam plates have, respectively, eccentric peripheral edges 76 and 78 (FIGS. 4 and 5) which are situated below the

arms

54 and 44 with which these arms are held engaged by

springs

80 and 82. Thespring 81 is connected at its upper end to the distal end of the arm 44 and at its lower end to the base of the frame. The spring 83 (FIG.

3) is connected at its upperend to the arm 54 and at its lower end to the arm 44.

The cam plate 70 (FIG. 2) has a forwardly projecting arm 80, at the forward end of which there is a diametrically extending arm 82, the upper end of which extends beyond the center of rotation of the cam and which supports a forwardly projecting shaft 84 with its axis coinciding with the center of rotation of the cam. The forward end of the shaft 84 has non-rotatably mounted thereon a knob 86 by means of which the shaft 84 may be rotated and in turnthecam plate 70 rotated. The cam plate 68 also has a forwardly projecting arm 88 at the forward end of which is a diametrically extending arm 90 to which there is fastened a plate 92 which extends upwardly parallel to the arm 82 and extends beyond the shaft 84. The plate 92 contains an opening 94 through which the shaft 84 passes and has secured thereto a forwardly extending sleeve 96 on which there is non-rotatably mounted a knob 98. The knob 98 provides for rotating the cam 68. As thus constructed, the

cam plates

68 and 70 are rotatable relative to each other.

A transmitter bar 100 (FIGS. 1, 4 and is pivotally mounted at one end on the pin 38 and extends therefrom transversely of the actuating

pins

52 and 60, the bar being movable about the pivot axis of the pin toward and from the actuating pins and being operable when engaged with the pins to effect their actuation. Movement of the transmitter bar 100 in response to pressure or temperature changes is effected by a transmitter rod 102, the upper end of which extends through an opening 104 (FIG. 2) at the top of the housing 62 and the lower end of which extends through an opening 106 at the bottom of the housing. The upper end is situated directly below the transmitter bar 100 and the lower end rests on an arm 108 pivotally supported at one end on a pin 110 fixed at its rear end in a boss 112 at the back of the frame and supported at its forward end in the lower end of the plate 40. The arm 108 extends transversely'from the pivot pin over an opening 114 (FIG. 1) at the base of the frame through which a plunger 1 16 extending from the motor 16. The arm 108 is operable to raise the transmitter rod 102 which, in turn, raises the transmitter bar 100.

The

earns

68 and 70 are adapted by rotation to displace the

arms

54 and 44 and hence the actuating

elements

60 and 52 relative to the transmitter bar 100 to cause the switches to be actuated at a predetermined pressure or temperature. The transmitter bar 100 has on it a post 118 (FIG. 2) which is threaded through it from the lower side directly below the actuating element 60, the post being adjustable relative to the actuating element. The transmitter bar also has on it a fixed lip 120 (FIGS. 1, 4 and 5) which is situated directly below the actuating element 52.

When both cams are rotated to positions wherein the portions of minimum radius are engaged with the transmitter bar, the actuating elements of both switches engage the transmitter bar. From this position the

arms

44 and 54 may be raised with respect to the transmitter bar by rotation of the cams to present portions of larger radius thereto, the switches being movable relative to each other except that the cam 68, which has engagement with the shorter arm is limited in its rotation relative to the cam 70 which has engagement with the longer arm so that the switch S2 can never be displaced with respect to the transmitter bar a distance which would result in actuation of the switch S1 before the switch S2. The maximum displacement is such that the two switches would be operated simultaneously. Limitation of rotation of the cam 68 is provided for by a lug 122 comprising part of a plate 123 (FIGS. 1 and 2) fastened to the arm 82 and a lug 124 comprising part of a plate 123 fastened to the plate 92 in a position such that it cannot pass the lug 122.

It is desirable to indicate on the dial D the pressure or temperature at which actuation of the switches takes place and the progress of the pressure or temperature change toward a predetermined point of operation. To this end the dial D is fastened to the front of the frame against forwardly projecting bosses 128-128 by means of screw bolts 130-130 on which there is a suitable scale. A pointer 132 is secured to the plate 123 for rotation with the arm 82 about the axis of the shaft 84. A pointer 134 is fastened to the plate 125 for rotation with the plate 92 about the axis of the shaft 84. The pointer 132 indicates the temperature or pressure at which the switch S1 is to be actuated and the pointer 134 indicates the temperature or pressure at which the switch S2 is to be actuated. To provide for indicating the progress of the temperature or pressure change a pointer 136 is fastened to the forwardly projecting end of the shaft 64 and this moves over the dial in response to rotation of this shaft, rotation being effected by a pinion 138 secured to the shaft and a rack 140 on the transmitter rod 102. A coiled spring 142 secured at one end to the shaft and at the other end to the frame normally operates to hold the pointer 136 at the zero position.

The instrument as thus constructed provides for selecting the temperatures or pressures at which the two switches are to be operated, provides for successive operation of the switches throughout the range for which the instrument is designed up to a maximum where the switches are operated simultaneously, and provides for indicating the progress of the pressure or temperature changes throughout the range for which the instrument is set to operate.

While switches are shown herein to illustrate the invention it is within the scope of the invention to substitute therefor valves or the combination of a switch and valve. Also the expandable motor 16 may be responsive to an increase in pressure or to the expansion of a volatile fluid volatilized by a change in temperature or by movement of any other member responsive to a change in a condition which it is desirable to control.

It should be understood that the present disclosure is for the purpose of illustration only and that this invention includes all modifications and equivalents falling within the scope of the appended claims.

I claim:

1. In a control instrument, a transmitter bar movable in response to a change in pressure, a pair of switches having switch actuating elements, pivotally supported arms mounting, respectively, the two switches with their actuating elements adjacent the transmitter bar, cams supported for rotation about a common axis with their cam surfaces engaged, respectively, with said arms, said cams being individually rotatable to displace the arms separately relative to the transmitter bar, means for effecting rotation of the cams and pointers movable with the cams indicative of the selected point of operation of the respective switches.

2. A control instrument according to claim 1, comprising means for'limiting rotation of one of the cams relative to the other so that at the position limited by said other cam the transmitter bar effects operation of both switches simultaneously.

3. In a control instrument, a transmitter bar movable in response to a change in pressure, a pair of switches having switch actuating elements, pivotally supported long and short arms supported at corresponding ends for pivotal movement about a common axis, said arms mounting the switches with their actuating elements at different radial distances from said axis, adjacent the transmitter bar, means operable to move the transmitter bar in response to a change in pressure, a pair of independently operable cams operably associated with the respective arms, rotation of which effects movement of the arms relative to each other and to the transmitter bar, means for effecting rotation of the cams and pointers associated with the respective cams indicative of the setting point of operation of the respective switches.

4. In a control instrument, a transmitter bar movable in response to a change in pressure, a pair of switches having switch actuating elements, pivotally supported long and short arms supported at corresponding ends for pivotal movement about a common axis, said arms mounting the switches with their actuating elements at different radial distances from said axis and from the pivot axis of the transmitter bar, with the actuating elements adjacent the transmitter bar, a pair of independently operable, rotatable cams supported with their edges, respectively, adjacent said arms, spring means yieldably holding the arms engaged with said cams, and means for rotating the cams independently of each other to preposition the actuating elements of the switches at different distances from said transmitter bar.

5. A control instrument according to claim 4, comprising means on the transmitter bar for engagement with the actuating elements, one of said means being adjustable relative to the other.

6. In a control circuit, an arm, support means pivotally supporting the arm at one end for angular movement relative to said pivot axis, a switch at the distal end of said arm, said switch having an actuating element, a second arm pivotally mounted at one end on said support means for angular movement relative to said pivot axis relative to the first arm, a switch mounted at the distal end of the second arm at a lesser radial distance from said pivot axis than the switch on the first arm, two cams supported adjacent said arms for engagement, respectively, one with the long arm and the other with the short arm, said cams being independently rotatable, spring means holding the respective arms engaged with the respective cams, a transmitter bar pivotally supported at one end with a portion extending transversely of said switches, a transmitter rod supported with an end adjacent said transmitter bar operable to effect angular movement thereof relative to said switches, means for rotating the cams to set the switch on the longer arm at a predetermined position relative to the transmitter bar and to set the switch on the shorter arm at a predetermined different distance from the switch on the shorter arm, and means limiting relative movement of the cam engaged with the shorter arm relative to the cam engaged with the longer arm to a position such that the transmitter bar will actuate both switches simultaneously.

7. In a control instrument, a transmitter bar movable in response to a change in pressure, a pair of switches having switch actuating elements, pivotally supported arms mounting, respectively, the two switches with their actuating elements adjacent the transmitter bar, cams supported for rotation about a common axis with their cam surfaces engaged, respectively, with said arms, said cams being individually rotatable to displace the arms separately relative to the transmitter bar, means for effecting rotation of the cams, a dial on which there is a scale, pointers movable by the cams as the latter are rotated to move the pointers on the scale to positions indicative of the selected point of operation of the respective switches, and a pointer movable with the transmitter rod as the latter is moved in response to a temperature-or pressure change to indicate theprogress of the temperature or pressure change with respect to the selected positions of operation of the switches.

8. An instrumentaccording to claim 16, wherein the transmitter bar has on it adjustable and fixed posts located, respectively, opposite the actuating element of the switch on the shorter arm and the actuating element of the switch on the longer arm.

Claims

2. A control instrument according to claim 1, comprising means for limiting rotation of one of the cams relative to the other so that at the position limited by said other cam the transmitter bar effects operation of both switches simultaneously.

7. In a control instrument, a transmitter bar movable in response to a change in pressure, a pair of switches having switch actuating elements, pivotally supported arms mounting, respectively, the two switches with their actuating elements adjacent the transmitter bar, cams supported for rotation about a common axis with their cam surfaces engaged, respectively, with said arms, said cams being individually rotatable to displace the arms separately relative to the transmitter bar, means for effecting rotation of the cams, a dial on which there is a scale, pointers movable by the cams as the latter are rotated to move the pointers on the scale to positions indicative of the selected point of operation of the respective switches, and a pointer movable with the transmitter rod as the latter is moved in response to a temperature or pressure change to indicate the progress of the temperature or pressure change with respect to the selected positions of operation of the switches.

8. An instrument according to claim 16, wherein the transmitter bar has on it adjustable and fixed posts located, respectively, opposite the actuating element of the switch on the shorter arm and the actuating element of the switch on the longer arm.