US1885054A

US1885054A - Electrically operated indicating apparatus

Info

Publication number: US1885054A
Application number: US231302A
Authority: US
Inventors: John W Anderson
Original assignee: Individual
Current assignee: Individual
Priority date: 1927-11-05
Filing date: 1927-11-05
Publication date: 1932-10-25
Anticipated expiration: 1949-10-25

Description

Oct. 25, 1932- J. w. ANDERSON 1,885,054

ELECTRICALLY OPERATED INDICATING APPARATUS Oct. 25, 1932. J. w. ANDERSON 1,885,054

ELECTRICALLY OPERATED INDICATING APPARATUS Filed Nov. 5. 1927 '7 Sheets-Sheet 2 Oct. 25, 1932. J. w. ANDERSON ELECTRICALLY OPERATED INDICATING APPARATUS Filed Nov. 5. 1927 7 Sheets-Sheet 3 Oct. 25, 1932. J, w, ANDERSON 1,885,054

ELECTRICALLY OPERATED INDICATING APPARATUS Filed NOV. 5. 1927 '7 Sheets-Sheet 4 Oct. 25, 1932. J. w. ANDERSON ELECTRICALLY OPERATED INDICATING APPARATUS Filed Nov. 5. 1927 7 Sheets-Sheet 5 Oct. 25, 1932. J. w. ANDERSON ELECTRICALLY OPERATED INDICATING APPARATUS Filed Nov. 5. 1927 '7 Sheets-Sheet 6 .3@7 320 was? f 25 2749124. K 5v3f6 30a wf/Moy Oct. 25, 1932. J. w. ANDERSON ELECTRICALLY OPERATED INDICATING APPARATUS Filed Nov. 5. 1927 7 Sheets-Sheet 7 Patented Oct. 25, 1932 UNITED STATES JOHN W. ANDERSON, F GARY, INDIANA ELECTRICALLY OPERATED INDICATING APPARATUS Application led November 5, 1927. Serial No. 231,302.

My invention relates to electrically oper-` V electrical conductors, coils, resistors, ete.

Another particular object of the invention is to provide electrically operated apparatus, which functions substantially independently of the voltage impressed thereon, for meas- "9 uring electrical resistance.

Still another particular object of the invention is to provide an improved method of measuring the electrical resistance of an object.

Many other objects and advantages of the construction herein shown and described will be obvious to those skilled in the art from the disclosure herein given.

To th1s end my invention consists 1n the fr novel construction, arrangement and combination of parts herein shown and described, and more particularly pointed out in the claims.

In the drawings, wherein like reference characters indicate like or corresponding parts:

Fig. 1 is a diagrammatic view of apparatus which embodies the invention;

Fig. 2 is a seeeon taken through a structure which forms part of the apparatus shown in Fig. 1;

Fig. 3 is a section taken on line 3-3 of Fig. 2;

Fig. 4 is a section taken on line 4-4 of Fis. 3;

Fig. 5 is a section taken on line 5-5 of- Fig. 3;

Fig. 6 a front elevation of another instrument which forms part of the improved 1 apparatus shown in Fig. 1;

Fig. 7 is a section taken on line 7-7 of Fig. 6;

Fig. 8 is a section taken on line 8-8 of Fig. 7;

' Fig. 9 is a section taken on line 9-9 of 55 Fig.

Fig. 10 is a perspective view of a device Which forms part of the embodiment of the invention illustrated in Fig. 1;

Fig. 11 is a diagrammatic view of apo0 paratus which embodies another form of the invention;

Fig. 12 is a section taken through an instrument which forms part of the apparatus shown in Fig. 11;

Fig. 13 is a section taken on line 13-13 of Fig. 12;

Fig. 14 is a section taken on line 14--14 of Fig. 13;

Fig. 15 is a section taken on line 15-15 70 of Fig. 14;

Fig. 16 is a diagrammatic View of appara- Ens embodying another form of the invenion;

Fig. 17 is a section taken through an instrument Which forms part of the improved apparatus shown in Fig. 16;

Fig. 18 is a section taken on line 18-18 of Fig. 17;

Fig. 19 is a section taken on line 19-19 of Fig. 18;

Fig. 2() is a front elevation of another instrument which forms part of the improved apparatus shown in Fig. 16; l

Fig. 21 is 1a section taken on line 21-21 of Fig. l

Fig. 22 is a section taken on line 22-22 of Fig. 21;

Fig. 23 is a diagrammatic view of apparatus which embodies still another form of the invention;

Fig. 24 is a section taken through apparatus which forms part of the improved apparatus shown in Fig. 23;

Fig. 25 is a section taken on line 25-25 of Fig. 24;

Fig. 26 is a front elevation of another instrument which forms part of the improved apparatus shown in Fig. 23;

Fig. 27 is a section taken on line 27-27 of Flg. 26;

Fig. 28 is a section taken on line 28-28 of Fig. 27; and y Fig. 29 is a section taken on line 29--29 of "Ivreav n the illustrated embodiments of the invention, apparatus is shown and described which comprises means for roducing pulsations of electrical energy a apted to control the operation of indicating instruments. Apparatus of this character is shown in the copending applications of Theodore J. Smulski, Serial Nos. 133,426, 147,076, 156,054, 169,114 and 169,115, filed September 3, 1926, November 8, 1926, December 20, 1926, February 17, 1927, and February 17, 1927 respectively, and it is to be understood that no claim is made to the subject matter of these copending applications. The appended claims distinguish betwen the inventions disclosed in the aforementioned copending applications and my invention.

Referring for the present to Figs. 1 to 10, inclusive, and more particularly to Figs. 1 to 5, inclusive, I have shown an-instrument which is designated generally b the reference character 12 and is hereina r referred to as the primary instrument. The primary instrument 12 preferably com rises a base plate 14, or the equivalent, w ich is referably formed from electrical insulation. Iigidly secured to the base plate 14 is a bracket 16 having lugs 17 in wh1ch a shaft or pin 18 is journaled. Mounted upon the pin 18 is a block 19 preferably formed from electrical insulation. A bi-metallic thermostat 21 has one of its ends rigidly secured to the block 19 and has the other of its ends provided with a contact point 22 which normally engages a contact point 23, the contact point 23 being screw-threaded through a substantially U- shaped bracket 24 which is rigidly secured to the base plate 14. Obviously, the contact point 23 may be brought into a plurality of adjusted positions to take up wear upon 1t or the Contact 22. Another advantage of this construction will presently appear. Wound around the thermostat 21 is an electrical resistance 26 which is electrically insulated from the thermostat throughout the greater portion of its length but has one of its ends electrically connected to the free end of the thermostat. The other end of the winding or electrical resista-nce 26-is preferably connected to a binding post 27 mounted in the base plate 14.

In that form of the invention illustrated in Figs. 1 to 10, inclusive, I preferably employ a bi-metallic thermostat 30 which cooperates with the thermostat 21 to prevent my imroved apparatus from becoming inaccurate cause of changes in the temperature of the ambient air. The thermostat 30 is preferably substantially identical with the thermostat 21 and is preferably provided with an insulating sleeve 31 which corresponds to an insulating sleeve 32 provided upon the thermostat 21 to insulate the windin or resistance 26 therefrom. The provision o the sleeve 31 upon the thermostat 30 insures that this thermostat will be affected by the temperature of the ambient air to the same extent as the thermostat 21. As shown, one end of the thermostat 30 is rigidly secured to the block 19 and the other end thereof engages a set screw 34 which is screw-threaded into the U-shaped bracket 24. The free end of the thermostat 30 is held in engagement with the set screw 34 by a compression spring 35 which is held in position by a set screw 37 screw-threaded into the bracket 24.

The

thermostats

21 and 30 are so const-ructed that when they are subjected to an increase in temperature, the free end thereof tends to move to the right (Fig. 3), the arrangement being such that if the thermostat- 21 is heated by current flowing through the resistance or winding 26, the contact 22 will be disengaged from the contact 23. However, if the temperature of the ambient air rises to such an extent that the thermostat 21 flexes and tends to disengage the contact 22 from the contact 23, the thermostat 30 will res ond simultaneousl to the same extent an will angularly dlsplace or rotate the block 19 in a counter clockwise direction (Fig. 3) around its pivotal axis so that the contact 22 will remain in engagement with the contact 23. Of course, if the thermostat 21 is then subjected to the heat produced by a current flowing through the winding or resistance 26, the thermostat 21 will flex or tend to displace the contact 22 from the contact 23 as the thermostat 30 is not subjected to the heat of the current.

In Figs. 6 to 9, inclusive, I have illustrated the details of construction of a secondary instrument which I employ in that embodiment of the invention illustrated in Figs. 1 to 13, inclusive. The instrument shown in Figs. 6 to 9, inclusive, is designated generally by the reference character 40 and preferably comprises a housing 41 having a back wall 42 and a dial plate 43. Pivoted in blocks 44 and 45 which are rigidly secured to the back wall 42 and the dial plate 43, respectively, is a shaft or pin 46 which carries a'block 47 preferably formed from electrical insulation. Secured to the block 47 are two

thermostats

50 and 51 which may be of any suitable construction but which, in this instance, are substantially flat bi-metallic bars, one end of each bar being secured to the block 47. The free end of the thermostat engages a U- shaped bracket member 52 which is constrained to rotate with pins 53 and 54, the pins 53 and 54 being journaled in the dial plate 43 and a bracket 56, respectively. A spiral spring 57 has one of its ends secured to the pin 54 and has the other of its ends scthe bracket member 52 in such manner that cured to a pin 59 which projects from the bracket 56, the construction being such that the spring 57 tends to rotate the bracket member 52 in a clockwise direction (Fig. 8) to hold it in engagement with the free end of the thermostat 50. A pointer or hand 6() secured to the bracket member 52 by the pin 53 is adapted to traverse a scale 62 printed or otherwise marked upon the dial plate 43. Disposed around the thermostat and insulated therefrom is a winding or resistance 64 which has one of its ends connected to a binding post 65 and has the other of its ends connected to a binding post 66, the binding posts 65 and66 being preferably mounted upon the housing 41.

It will be noted that a compression spring 69 yieldingly holds the free end of the thermostat 51 in engagement withA a set screw 70 which is screw-threaded in a U-shaped brack` et 72 rigidly secured to the back wall 42, the construction being such that the set screw may be manipulated to displace the thermostats. 50 and 51 and the pointer or hand 6() with respect to the scale 62. This construction permits the instrument to be adjusted quickly and easily. The thermostat 52 is preferably provided with an insulating sleeve 74 which is substantially identical in construction with an insulating sleeve 75 provided to electrically insulate the resistance or winding 64 from thethermostat 50. The

thermostats

50 and 51 are so constructed that the free ends thereof tend to move to the right (Fig. 8) when the thermostats are subjected to an increase in temperature. If both thermostats are subjected to the same increase in temperature, the thermostat 50 will fiex or tend to displace the bracket member 52 in such manner that the pointer or hand 60 will be angularly displaced in a clockwise direction (Fig. 6) around the pivotal axes of the pins 53 and 54 and against the-action of the spring. `But as the thermostat 51 flexes or bends to the same extent, it will rotate the block 47 around the axis of rotation of the shaft 46through an angle which will cause the free end of the thermostat 50 to remain in the position where it was before the

thermostats

50 and 51 were subjected to the rising temperatu However, if the thermostat 5() 'is then 'subje ted to the heat of an electrical current flowing through the winding 64, it will continue to flex or bend and will displace 'conductor 82 to one terminal of a switch 83 which has its other terminal connected by a conductor to conductors 86 and 87. The conductor 87 connects conductor 85 with the aforementioned binding post 65 of the secondary instrument 40 and the conductor 86 connects the conductor 85 with a metallic U- shaped clip 88 mounted upon an insulating base 89 which also carries a U-shaped metallic clip 90 substantially identical in construction with the metallic clip 89.

The binding post 28 of the primary ,instrument 12 is connected by a conductor 91 to conductors 92 and 93. The conductor 92 connects the conductor 91 with one terminal of an electrical resistance element 94 which has its other terminal connected by a conductor 95 to the binding post 66 of the secondary instrument 40. .The conductor 93 connects the conductor 91 with the clip 90.

As shown in Figs. 1 and 10, the metallic clips 87 and 89 are so constructed that a device which is to be tested may be mounted therein. Thus, I have shown a resistance element '97 which is enclosed in a tube 98 which is formed of any suitable electrical insulation. Metallic caps 10() mounted upon the ends of the tubular member 98 are soldered or otherwise electrically connected to the resistance element 97 and each of the ca s100 is preferably provided with a metallic ug or blade 101 adapted to be inserted in one of the clips 88 or 99 to electrically connect the resistance element 97 with the

conductorsv

86 and 93. It is to be understood, of course, that the resistance element 97 does not form part of my improved apparatus but simply illustrates the use to which the invention maybe put. Thus, resistance-elements ofldiflerent constructions, coils or other electrical units* which must be tested, may be electrically connected to theconductors 86 and 93 through the medium of the clips V88 and 90,` or the equivalents for the purpose.

Toprevent sparking between the contact points 22 and 23, I preferably shunt a relaltively high resistance 25 across the instrument 12. However, any other suitable construction may be employed in place of the resistance 25 to prevent or reduce sparking between the contact points 22 and 23. ,s

The operation of the above described apparatus is substantially as follows: Assuming that the contact 22 engages the contact 23 and that the switch 83 has been closed, it is readily understood that if the apparatus is to be cm- 7 ployed to test the resistance of an electrical unit such as the resistance element 97, the electrical resistance or resistance element 97 may be inserted in the clips 88 and 90, or the equivalents for the purpose, so that an electricalfcrrent will fiow as follows: from the battery 81 through the conductor 82` the switch 83. andthrough the conductor 85 to divide and fiow through the conductors 86 and 87. That branch of the current which flows 7" through the conductor 86 passes through the clip 88, the resistance element 97 and thence through the conductor 93 to the conductor 91. The other part of the divided current lo'ws 5 through the conductor 87, the binding post 65,

-. ductors 92 and 93 flows through the conductor 91, the binding post 28, the contact 23, the contact 22, a portlon of the thermostat 21, the

winding 26, the binding post l27 and through' the conductor 8() back to the battery 81. The

thermostat- 21 is heated by the current flowing through the Winding 26 and ilexes or bends to disengage `the contact 22 from the contact 23 so that the circuit is opened and no current flows therethrough. However, while current en .iS flowing through the winding 26, the thermowise direction (Fig. 6).

stat 50 is heated by the current flowing through the windin 64 and it flexes or bends to displace the han or pointer in a clock- When the contact 22 is disengaged from the contact 23 and the circuit is opened, the

thermostats

21 and 50 cool so that the contact 22 again engages the contact 23 and the hand or pointer 60 rotates through a relatively small angle in a counter clockwise direction (Fig. 6), However, as soon as the contact 22 again engages the contact 23,the circuit is closed and the

thermostats

21 and 50 are again heated by the -electrical current flowin through the

windings

26 and 64, respective y. This cycle of operations is continually repeated until, the

switch 83 is opened and the heat to which the thermostat 50l is subjected during the operation of the apparatus causes the thermostat 50 to bring `the hand or pointer 60 into'a position wherein itf indicates in ohms, or the equivalent, upon the scale 62, the resistance of the device being tested. The position assumed by the pointer 60 is independent of any variation in the voltage impressed upon the circuit by the storage battery 81, or its equivalent, as variations in the voltage are compensated by corres onding variations in the duration of indivi ual pulsationsof current in the circuit, each pulsation of current being capable of performing an amount of work determined'by the position of th contact 23. Of course, as long as the cont ct re mains in one position with respect to the axis of rotation of the block* 19, each of the several pulsations of current is capable of performing the same amount of work.' If the voltage drops, the current flows for a longer time during each pulsation-and if the voltage increases, the current flows for a shorter period of time during each pulsation. Sullicient current must flow during each pulsation to heat the thermostat 21 to such an extent that the contact 22 will be disengaged from the contact 23. The average flow of current throu h the circuit will remain constant even thoug the voltage varies. The amount of current which flows through the winding 64 is less than that whichflows through the winding 26 but the thermostat 50 is so constructed that its free end is displaced through a relatively large distance by the current which flows through the winding 64.

Now if it is assumed that the resist-ance element 97 is replaced by one which is of similar construction but which has a different electrical resistance, a different proportion or part of the current will flow` through the winding 64 and the pointer 60 will be brought into a different position. Of course, known resistances may be placed in the circuit between the

conductors

86 and 93 and the scale 62 maybe calibrated to indicate the positions of the pointer-60 for any given resistance. Itis well to note that if the voltage impressed upon the current remains constant and the resistance element 97 is rev placed by one having a different value of electrical resistance, the current flowing through the winding 26 will be of a different value than the current which flowed through From the foregoing description of the operation of the above described apparatus, it is readily understood that if the scale 62 has been properly calibrated, the improved api j.

paratus may be employed to measure the resistance of electrical units such as electrical conductors, coils, resistors', etc. In some instances, it niay be, desirable to omit-the re sistance 94 from the circuit and for this reason, it should be understood that I am limited to its use only to the extent indicated in the appended claims.

It is, ofcourse, understood that a relatively small electrical current will flow through the resistance element 25 whenever the switch 83 is closed and that this current i will be of maximum value when the contact 22 is disengaged fromthe contact point23, However, the electrical current which flows through the circuit because of the insertion of the resistance 25 between the binding posts 27 and 28- is negligible as far as its effect upon the instrument 40 is concerned. While l this current will vary in strength in accordance with variations in the voltage impressed.'

upon the circuit, such fluctuation in -the strength of the current will not afe the instrument 40.to such an extent that t e readings thereof will be rendered inaccurate. It

should be also noted that this current is automatically taken into consideration when the apparatus is calibrated. In the preferred embodiment of the invention, the resistance is of such a high value that the hand or pointer does not indicate whether or not the resistance 25 is in the circuit. Thus, if the resistance 25 is in the circuit and the hand or pointer assumes a certain position with respect to the scale 62 and the resistance 25 is then removed, the hand or pointer does not move relative tothe scale.

The amount of work each pulsation of current flowing through the circuit is capable of performing is determined by the position of the contact point 23. 1f, at any time, it is desired to increase the strength of these pulsations, it is only necessary to displace the contact point 23 toward the contact point 22 so that the, thermostat 21 must be raised to ahigher temperature to have it disengage the contact point 23 from the contact point 22. A like yresult may be obtained hy manipulating the screw 34 to displace the contact point 22 in a direction toward the contact 23. Of course, if the contacts are engaging each other and an attempt is made to displace either one toward the other, the result is that the thermostat 21 is tensioned and a larger amount of the heat is required bodying another form of the invention, the

reference characters 105 and 40a designate primary and secondary instruments, respectively. which resemble the primary and

seconda ry instruments

12 and 40 shown in Fig. 1. The primary instrument 105 differs somewhat from the primary instrument 12 but thc secondary instrument 40al is substantially identical in construction with the aforementioned secondary instrument 40 and the parts thereof are identified by the same reference numerals. However, in the ease of the secondary instrument 40a, each reference numeral has the letter a added to it.

As shownin Figs. 11 to 15. inclusive. the primary instrument 105 preferably comprises a suitable base plate 106 which is preferably formed of electrical insulation and rigidly secured to the plate 106 are a plurality ot bracket members 107. 108 and 10S). Preferably formed integral with the bracket member 107 are. lugs 110 which journal a pin or shaft 1 1 upon which a block 113 is mounted, the block 113 being preferably formed from electrical insulation. A thermostat 115 has one of its ends rigidly secured to the block 113 erably formed from electrical insulation and is mounted upon a pin or shaft 121 which is journaled in lugs v123 formed integral With the bracket 109. Wound around the thermostat 115 is a Winding or electrical resistance 125 which has one of its terminals connected to a binding post 127 mounted in the base plate 106. The Winding 125 is electrically insulated from the thermostat 115 throughout the greater portion of its length but has one of its terminals soldered or otherwise electrically connected to the free end of the thermostat.

Wound around the thermostat 118 is a winding or electrical resistance 130 which has its terminals connected to

binding posts

132 and 133 mounted in the base plate 106. The winding or electrical resistance 130 is electrically insulated from the thermostat 118 by a sleeve 135 of electrical insulation. Electrically connected to the thermostat is a conductor 137 which is connected to a binding post 138 mounted in the base plate 106.

Thermostat 140 has one of its ends rigidly secured to the block 113 and its other end is held in engagement with a set screw 142 by a. compression spring 143, the set screw 142 being screw-threaded in the bracket 109. A sleeve 144 disposed around the thermostat 140 is preferably identical in construction with a sleeve 145 which electrically insulates most of the winding 125 from the thermostat 115. The

thermostats

115 and 140 are preferably substantially identical in construction so that they Will bend or flex equally When they are heated to any given temperature. This prevents the contact 116 from being displaced relative to the contact 117 when the

thermostats

115 and 140 are both subjected to the same degree of heat. However, the instrument may be adjusted by manipulating the set screw 142.

Rigidly secured to the block 120 is one end of a thermostat 150 which has its other end interposed between a set screw 152 and a compression spring 153, the set screw 152 being screw-threaded in the bracket 109 and the compression spring 153 being arranged to hold the free end of the thermostat 150 in engagement with the set screw 152. The thermostat 150 is preferably substantially identical in construction with the thermostat 118 so that it will bend or flex to the same degree when both of the thermostats are heated to the same temperature. This prevents displacement of the contact point 117 relative to the contact point 116 because of changes in the temperature of. the ambient air. The set screw 152 may also be manipulated to adjust the instrument 105.

At 88a and 90a in Fig. 11, l have shown metallic clips which are substantially identical with the aforementioned metallic clips 88 and 90, respectively, the metallic clips 88a and 90a being mounted upon a suitable inj flow into the

conductors

166 and 167.

sulating base 89a. Removably positioned in the clips 88a and 90a is an article to be tested which comprises a resistance element 97a, the resistance element 97a being electrically connected to the clips 88a and 90a.

Referring now to Fig. 11, it will be noted hat the binding post 127 is connected by a conductor 160 to a suitable source of electrical energy such as a storage battery 161 which has its other terminal connected by a conductor 163 to one terminal of a switch 164, the other terminal of the switch 164 being connected by a conductor 165 to two

conductors

166 and 167. The conductor 167 is connected to the clip 88a and the conductor 166 connects the conductor 165 to the binding post a. The clip 90a is connected by a conductor 169 to a 'conductor 170 which is connected to the binding post 130e. The binding post 66 is connected through a resistance 172 to a conductor 173 which is connected to the conductor 170. It will b e noted that the winding 130 is shunted across the resistance 17 2. Thus, the binding post 132 is connected by a conductor 174 to one terminal of the resistance and the binding post 133 is connected by a conductor 17 5 to the binding post 66a.

The operation of the apparatus shown in Figs. 11 to 15, inclusive, is substantially as fol ows Assuming that the contact point 117 is engaged by the contact point 116 and that the switch 164 is closed an electrical current will flow as follows: lrzrom the battery 161 through the conduct-or 163, the switch 164, and through the conductor 165 to divide and The current which lows through the conductor 167 also flows throu h the clip 88a, the resistance element 97a, t e clip 90a and through the conductor 169 to the conductor 17 0. The current which flows through the conductor 166 also flows through the binding post 65a, the winding 64a, and throu h the binding post 66 to divide and `flow t rough the resistance 172 and the conductor 175. The current which flows through the resistance 172 is delivered to the conductor 173 and the current which flows through the conductorw 175 is lead through the binding post 133 and the winding 130 and thence through the binding post 132 and the conductor 174 to the conductor 173 which, of course, delivers all of the current flowing in it to the conductor 170. The current flowing through the conductor -170 also flows through t e binding post 138, the thermostat 118, the contact point 117, the contact point 116, a portion of the thermostat 115, the winding and thence through the binding post 127 and the conductor 160 back to the battery 161. The thermostat 118 is constructed so that`when it is subjected to an increase in temperature, it bends and moves the contact point 117 toward the free end of the thermostat 115 and the thermostat 115 is so constructed that when it is subjected to an increase in tern erature, it bends and moves the contact point 116 away from the free end of the thermostat 118. The thermostat 118 and the winding are so proportioned that when the apparatus is in operation, the free end of the thermostat is displaced through a distance which is smaller than the distance throu h which the contact point 116 is displacec However, it is readily understood that the position assumed by the contact point 117 when the apparatus is in operation is determined by the amount of current which flows through the winding 130. The distance through which the contact 117 is displaced is determined primarily by the current flowing through the winding 130. It is readily understood that when the circuit shown in Fig. 11 is closed and the current flows therethrough, the current flowing through the windings 130 and 125 causes the thermostats to flex or bend until the thermostat succeeds in disengaging the contact 117 from the contact 116. Any suitable means or any suitable method may be employed to hold the contact point-

s

116 and 117 in engagement during the initial flow of current therethrou h so that the thermostat 115 will not imme iately disengage the contact point 116 from the contact point 117. Thus, the instrument 105 may be constructed so that when all of the thermostats in the instrument are of the same temperature as the ambient air, the

thermostats

115 and 118 may be slightly tensioned to hold the

contacts

116 and 117 in engagement with each other. Then when the thermostat 115 Ibends or flexes to withdraw the contact point 116 from engagement with the contact point 117, the contact point 117 will follow the contact point 116 through a distance which is determined by the value of the current flowing through the winding 130. When the contact 116 is disengaged from the contact 117, the circuit is opened and the

thermostats

115 and 118 immediately cool so that the contact point 117 is again engaged by the contact 116. This cycle of operations is continually repeated untilV the switch 164 is opened. The heat to which the thermostat 50a is subjected during the operation of the apparatus causes the thermostat 50a to bring the hand or pointer 60a into a position wherein it indicates in ohms, or the equivalent, upon the scale 62a, the resistance of the device being tested. It will be readily understood from the description of the apparatus shown in Figs. 1 to 10, inclusive, that the position assumed by the pointer 60ais independent of variations in the voltage impressed upon the circuit shown in Fig. 11 and that the apparatus shown in Fig. 11 functions to a large extent in the same manner as the apparatus shown in Fig. 1. The contact point 117 of Fig. 11 corresponds to the Contact point 23 of Fig. 1 but instead of being stationary like the contact 23, it moves into positions which are determined by the value of the currentJ flowing through the winding or resistance 130 and this, of course, determines the total amount of energy that flows through the circuit each time the contact point 117 is engaged by the contact point 11G, it being understood that the farther the contact point 117 is displaced from/ its normal position, the more energy is required to flex or bend the thermostat 115 into a posi-tion wherein its contact is disengaged from the contact 117.

Of course, various known resistance may be connected into the circuit between the clips 88a and 90a and the positions assumed by the pointer 60a when these known resistances are in the circuit may be indicated upon the scale 62a. Then when unknown resistances are introduced into the circuit, the pointer 60a Will correctly indicate the electrical resistance thereof.

In some embodiments of the invention, I may dispense with the resistance 172 and conncct the

conductors

174 and 175 to the binding posts 66e/ and 65a, respectively, and in other embodiments of the invention, I may retain the resistance 172 but connect the conductor 175 to the binding post 65a instead of to the binding post 66a.

Referring now to Figs. 16 to 22, inclusive, wherein l have shown apparatus embodying another forni of the invention, the

reference characters

200 and 201 designate instruments which are hereinafter referred to as the primary and secondary instruments, respectively. As best shown in Figs. 17, 18 and 19, the primary instrument 200 preferably comprises a permanent magnet 203, or the equivalent, between the poles of which is arranged a winding or coil 205 carried upon a. frame 206 which is made of any suitable material such as aluminum, or the like. The frame 206 is pivoted by pins 210 and 211 upon a block 212 which is preferably formed from iron and which is preferably rigidly secured to a bar 213 secured to the magnet 203. The bar 213 extends between the poles of the magnet and for this reason, is preferably constructed from some non-magnetic material. The pin 211 is preferably rigidly secured to the frame 206 so that it is constrained to rotate therewith and secured to the pin 211 is a lever 215 if which carries a contact point 216 engageable with a contact point 217, the Contact point 217 being serew-threadcd through an L- shaped bracket 218 which is rigidly secured and electrically insulated from a base plate 219 which supports the parts of the instrument 200. pair of spiral springs 220 yieldingly urge the frame 20G, and therefore, the contact point 216, in a counter clockwise direction (Fig. 8) so that the contact point 216 normally engages the contact point 217. The

contact point 217 is preferably provided with a knurled head 223 whereby the contact point may be rotated to bringit into a plurality of adjusted positions. This permits the Contact point 217 to be employed to adjust the instrument 200 and the apparatus whereof it forms a part. In this and other respects, it has the same functions as the contact 23 of Fig. 1. It may be mentioned at this point in the description that any suitable means may be provided to prevent sparking between the contacts 216 and217.

As illustrated in Figs. 20 to 22, inclusive, the instrument 201 preferably comprises a housing member 230 in which a permanent magnet 232 is mounted. Interposed between the poles of the magnet is a winding or coil 233 which is carried by a frame 234 preferably formed from some suitable material such as aluminum. The frame 234 is pivoted by

pins

235 and 236 to a block 237 preferably formed from iron, the block 237 being rigidly secured to a bar 238 carried by the magnet 232. The bar 238 is formed from some nonmagnetic material. The pin 235 is constrained to rotate with the frame 234 and its outer end projects through a slot 237 formed in a dial plate 240 which is mounted in the housing 230. A hand or pointer 242 rigidly secured to the pin 235 is adapted to traverse a scale 244 marked upon the dial plate 240.

As illustrated in Fig. 16. one terminal of the winding 205 is electricallyconnected to the lever 215 and the other terminal of the winding is connected by a conductor 246 to a storage battery 247. However, it will be understood that any-suitable source of electrical energy may be used in place of the storage battery 237 if it is so desired. The other terminal of the storage battery 237 is connected by a conductor 248 to one terminal of a switch 249 which has its other terminal connected by a conductor 250 to conductors 251 and 252. The conductor 251 connects the conductor 250 with one terminal of the winding 201 Which has its other terminal connected to one terminal 0f a resistance element or winding 254 and the other terminal of the resistance element 254 is connected by a conductor 256 to a conductor 257 which is connected to the contact member 216. The conductor 252 is connected to a clip 38.7) mounted upon a base 897) which is preferably formed from electrical insulation' and preferablyY carries a second clip 90b. The

clips

335 and 90?) are preferably substantially identical in construction with the aforementioned clips 88 and 90, respectively, and they are adapted to hold an article 97?) which may be connected into the circuit when the electrical resistance thereof is to be ascertained. The article U7?) may comprise a resistai ce element of the kind shown at 97 in Fig. 1 or it may comprise any other electrical unit such as a coil, fuse, con

ductor, etc., or the like. .The clip 90b is connected by a conductor 260 to a conductor 257.

The operation of the apparatus illustrated in Figs. 16 to 22, inclusive, is substantially as follows: Assuming that the switch 249 l is in its closed position and that a device 976 has been connected into the circuit by posiductor 252 will flow through the clip 88?),

the article 971), the clip 90b and thence through the conductor 260 to the conductor 257. The current delivered to the conductor 257 by the

conductors

256 and 260 will flow through the contact points 216, and 217, the lever 215, the coil 205 and thence through the conductor 246 back to the battery 247. Thus current will build up a magnetic field between the poles of the magnet 203, the construction of the instrument 200 being such that when this reaction takes place, the coil 205 and the lever 215 will be angularly displaced in a clockwise direction around the I pivotal axis of the coil 205 to disengage the contact 216 from the cont-act 217. However, as socn as the contact 216 is disengaged from the contact 217, the field built up in the coil 205 dies and the springs 220 return the coil 205 and the lever 215 into positions wherein the contact point 216 again engages the Contact point 217.l Obviously, this sequence of operations will be continued as long as the switch 249 remains in its closed position. It will be readily understood that the apparatus functions substantially independently of variationsin they voltage impressed upon the circuit. In other words, if the voltage is relatively high, the lield in the coil 2 5 will quickly build up to sufficient streng h to cause thecoil .to swing into a position wherein the contact point 216 isdisengaged from the contact point 217 and if the voltage impressed upon the circuit decreases in value, it will take a longer time to build up a field of suflicient strength in the coil 205 to cause it to bring the contact point 216'out of engagement with the contact point 217. As the coil 233 is in series with the-coil 205, a magnetic field will be set up therein each time a magnetic field is set up in the coil 205., In practice, the instrument 201 is preferably so designed that the field set up therein will be of greater strength than the field set up in the instrument A200 and the coil 233 will be displaced through a relatively large angle. Of-course, displacement of the coil 233 is accompanied by the like displacement of the hand or pointer 242 and it indicates upon the scale 244, the angle through which the coil 233 is displaced. In some instances, I may prefer to construct the instrument 201 in such manner that the field set up therein is substantially identical to the field set up in the instrument 200 but when this construction is employed, the springs 222 are made somewhat stronger than the springs 233a so that there will be a relatively large displacement of the coil 233 each time the coil 205 is dis laced to bring the contact point 216 out o engagement with the contact point 217.

The strength of the fields built up in the

coils

205 and 233 are determined by the strength of the currents flowing therethrough and the rate of change in these currents. Therefore, it is readily understood that when a constant electrical resistance is electrically connected into the circuit into the conductors 252 and 260 and the switch 249 is closed, the hand or pointer 242 will indicate uponthe scale 244, thev value of said resistance. Of course, the hand or pointer 242 will vibrate to some extent but this does not prevent accurate readings from being taken and if it is so desired, means may be provided to dampen the movements of the pointer. A number of known resistances may be introduced into the circuit to permit the scale 244 to be calibrated. After this has been done, the pointer 242 will indicate upon the scale, the resistance of any resistance element introduced in the circuit between the conductors 252 and 260.

In Figs. 23 to 29, inclusive, I have shown apparatus embodying still another form of the invention'. This apparatus preferably comprises a primary instrument 300 and a secondary instrument 301. As best shown in Figs. 23, 24 and 25, the primary instrument 300 is preferably of the hot wire type and preferably comprises a resistance wire 304 which has one of its ends secured to a metallic bracket 305 and has the other of its ends secured by a screw 306 to a block 307 which is preferably formed of electrical insulation. In this instance, the bracket 305 is secured to the block 307 by a bolt or binding post 309 which also secures the block 307 to a housing 310. The bracket 305 is pref; erably somewhat resilient and is preferably tensioned so that its` free end tends to move in a clockwise direction (Fig. 24) from the position wherein it is shown in Fig. 24. A wedge-shaped block 312i enga es the upper surface of the bracket 305 an also engages van inclined surface 314 formed upon a block 315 which is rigidlyjsecur'ed to the housing 310. A screw 316 journaled in the housing 310 is screw-threaded into the block 312 and may be manipulated to displace the block. Obviously, if the block 312 is displaced to the left (Fig. the free end of the bracket member305 will be lowered and if the block 312 is displaced to the right (Fig. 25) the 'izo free end of the bracket member 305 will move upwardly. To permit such movement of the free end of the bracket 305, the screw 316 is loosely journaled in the housing member 310 so that the free end of the bracket 305 may raise the block 312 and hold it in engagement with thc .surface 314.

Attached to the wire 304 substantially midway intermediate its ends is a metallic link 320 which is connected by a silk thread 321, or the equivalent, to a leaf spring 323, the leaf spring 323 being secured at one of its ends to a block 324 which is preferably formed from electrical insulation. A contact point 327 secured to the other end of the leaf spring normally engages a contact point 329 secured to one end of a bolt or binding post 330 mounted in the housing 310. lt will be noted that the right hand end (Fig. 24) of the wire 304 is connected by a conductor 33 to the leaf spring 323.

The details of the instrument 301 are illustrated in Figs. 26 to 29, inclusive, and it will be noted that it preferably comprises a housing member 335 carried by a base plate 336 which is preferably formed from electrical insulation. Secured to the base plate 336 by a bolt or binding post 337. or the equivalent, is a metallic bracket member 338 which is preferably somewhat resilient so that its left end (Fig. 23) tends to move upwardly from the position wherein it is shown in Fig. 28. A resistance wire 340 which is electrically connected to the bracket member 338 has one of its ends secured to the bracket and has the other of its ends secured to a binding post 341 mounted in the base plate 336. A sct screw 342 is screw-threaded into a base 344 which is mounted in the base plate 336,

thc construction being such that the set screw 342 may be manipulated to bring the free end of thc bracket 338 into a plurality of adjusted positions. Attached to the wire 340 intermediate its ends is a metallic link 345 which is also attached to one end of a silk thread 346, or the equivalent, the other end of the silk thread 346 being secured to the free end of an arcuate leaf spring 348 which has its other end secured by a'screw 349 to the base plate 336. Intermediate its ends the silk thread is wrapped around a sheave or pulley 350 which is journaled upon conical ends provided upon set screws 352 and 353, the set screws and 353 being screwthreaded through bars and 355 which are supported by the base plate 336. Secured to the pulleyor sheave is a hand or pointer 356 adapted to traverse a scale 357 arranged upon a dial plate 358, the dial plate 358 being mounted in the housing 335.

Referring now to Fig. 23, it will be noted that the binding post 309 is connected by a conductor 360 to one terminal 0f a suitable source of electrical energy such as a storage battery 361. ,1 conductor 363 connects the other terminal of the battery 361 to one terminal of a switch 365 which has its other terminal connected by a conductor 366 to conductors 367 and 368. The conductor 367 is connected to the binding post 341 of the instrument 301 and the binding post 337 of the instrument 301 is connected to one terminal of a resistance 370 which has its other terminal connected by a conductor 371 to a conductor 372. The conductor 368 is connected to a clip 38C which is mounted upon a base 890 preferably formed from electrical insulation. Also mounted upon the base plate 890 is a clip 900 which is substantially identical tothe clip 880. 1n this embodiment of the invention, the

clips

880 and 900 are substantially identical to the aforementioned clips 88 and 90 and have the same functions. Thus, a device 97 c such as the device 97 shown in Fig. 1 may be positioned in the

clips

880 and 900 to connect it into thecircuit shown in Fig. 23. The device 97C may be a coil, a conductor or any other device of which the electrical resistance is to be ascertained. A conductor 373 connects the clip 900 with the conductor 372 which connects the

conductors

371 and 373 with the contact point 329 of the instrument 300.

The operation of the apparatus shown in Figs. 23 to 29, inclusive, is substantially as follows: Assinning that a device 97o has been positioned in the clips 88C and 00C and that the switch has been closed. an electrical current will fiow as follows: From the battery 361, through the conductor 372, the switch 365, the conductor 366 and thence into the conductors 367 and 368. The current delivered to thc conductor 367 will flow through the binding post 341, the wire 340, the bracket member 338, the binding post 337, the resistance 370 and thence through the conductor 371 to the conductor 372. The current delivered to the conductor 368 will flow through clip 88o, the device 970, the clip 90e and thence through the conductor 373 to the conductor 372. The current delivered to the conductor 372 by the

conductors

371 and 373 will iow through the Contact point 329, the contact point 327, the leaf spring 323, the conductor 333, the wire 304, the bracket member 305, the binding post 309 and thence through the conductor 360 back to the battery 361. The current which flows through the wire 340 heats it and causes it to expand whereupon the spring 323 is permitted to disengage the contact 327 from the contact 329. This opens the circuit and the wire 340 cools so that the s ring 323 is drawn back into the position w erein its contact point 327 is again engaged by the contact point 329. This sequence of operations is continued as long as the switch 365 remains in its closed position. Each time the contact point 327 engages the contact point 329, a portion of the current fiowing through the wire 304 also flows through the wire 340 so that it is heated and the silk thread 346 is displaced by the leaf spring 348 to rotate the pulley 350. 0f course, rotation of the pulley 350 is accompanied by similar' displacement of the hand or pointer 356. The instrument 301 is preferabl so designed that a relatively small current owing through the wire 34() will cause displacement of the hand or pointer 356 through a relatively large angle. In

` other words, the wire 340 elongates much more quickly and to a greater extent than the wire 304. The amount of current flowing through the wire 340 is, of course, determined by the resistance of the device 970. Thus, if the device 97 c is replaced by one having a greater electrical resistance, more current Will iow through the wire 340. The scale 357 may be calibrated by placingr known resistances in the clips 880 and o and then indicating upon the scale the position assumed by the pointer. Then, if unknown resistances are placed in the

clips

880 and 900, the pointer will indicate the values thereof. In the event that the contact points 327 and 329 become worn or if for any other reason, the pointer 357 does not indicate accurately the resistances of devices inserted in the

clips

880 and 900, the

screws

316 and 342 may be manipulated to bring the pointer into its correct position when a known resistance has been placed in the clips. Obviously, the apparatus may be calibrated from time to time to take care of wear in the parts thereof.

Any suitable means may be provided for preventing sparking between the contact points 327 and 329 and the

screws

316 and 342 may be manipulated to adjust and calibrate the apparatus.

Having thus described my invention, it is obvious that various immaterial modifications may be made in the same without departing from the spirit of my invention; hence I do not wish to be understood as limiting myself to the exact form, construction, arrangement and combination of parts herein shown and described, or uses mentioned.

What I claim as new and desire to secure by Letters Patent is:

1. Apparatus arranged to form an electrical circuit for measuring electrical resistance, said apparatus comprising a source of current vibratory means for opening and closing said circuit to cause pulsations of electrical energy to flow therethrough and adapted to vary the duration of the pulsations upon the occurrence of variations of the voltage of the current source, indicating means in series with said vibratory means, said vibratory means and said indicating means being actuated by said pulsations of electrical energy, and means for connecting a resistance element to be measured in said circuit in series with said vibratory means and in parallel with said indicating means.

2. Apparatus arranged to form an electrical circuit for measuring electrical resistance,

said apparatus comprising vibratory means including a thermostat for opening and closing said circuit to cause pulsations of electrical energy to flow therethrough, indicating means in series with said vibratory means, said vibratory means and said indieating means being actuated by said pulsations of electrical energy, and means for connecting a resistance element to be measured in said circuit in series with said vibratory means and in parallel with said indicating means.

Apparatus arranged to form an electrical circuit for measuring electrical resistance, said apparatus comprising vibratory means for opening and closing said circuit to cause pulsations of electrical energy to flow therethrough, indicating means in series with said vibratory means and including a thermo-stat, said vibratory means and said indicating means being actuated by said pulsations of electrical energy, and means for connecting a resistance element to byl` measured in said circuit in series with said vibratory means and in parallel with said indicating means.

4. Ap aratus arranged to form an electrical circuit for measuring electrical resistance, said apparatus comprising vibratory means including a thermostat for opening and closing said circuit to cause pulsations of electrical energy to flow therethrough, indicating means in series with said vibratory means and including a thermostat, said vibratory means and said indicating means being actuated by said pulsations of electrical energy, and means for connecting a resistance eiement to be measured in said circuit in series with said vibratory means and in parallel with said indicating means.

5. Appartus arranged to form an electrical circuit for measuring electrical resistance, said apparatus comprising vibratory means for opening and closing said circuit to cause pulsations of electrical energy to flow therethrough, means for controlling said vibratory means to compensate for chan es in the temperature of the ambient air, indicating means in series with said vibratory means, said vibratory means and said indicating means being actuated by said pulsations of electrical energy, and means for connecting a resistance element to be measured in said circuit in series with said vibratory means and in parallel with said indicating means.

6. Apparatus arranged to form an electrical circuit for measuring electrical resistance, said apparatus comprising vibratory means for opening and closing said circuit to cause pulsations of electrical energ to flow therethrough, indicating means in series with said vibratory means, means for controlling said indicating means to compensate for variations in the temperature of the ambient air, said vibratory means and said ilu,

Ill

indicating means being actuated by said pulsations of electrical energy, and means for connecting a resistance element to be measured in said circuit in series with said vibratory means and in parallel with said indicating instrument.

T. A method of measuring the electrical resistance of an article which comprises arranging said article in an electrical circuit in parallel with a measuring instrument, and subjecting them simultaneously to an electrical currentv and maintaining the measuring eil'ect of the current constant when the voltage of the current source varies.

8. A method of measuring the electrical resistance of an article which comprises arranging said article in an electrical circuit in parallel with a measuring instrument` and subjecting them to an interrupted unidirectional current, and varying the duration of the current impulses upon variation of the voltage of the current source.

9. A method of measuring the electrical resistance of an article which comprises simultaneously subjecting said article and a measuring instrument to pulsations of electrical energy, each ot which pulsations is capable of performing an amount of work not affected by variations in the voltage impressed upon the source of said pulsations.

10. Apparatus arranged to form an electrical circuit for measuring electrical resistance, said apparatus comprising indicating means responsive to electrical current flowing in said circuit, means for connecting into the circuit an article of which the electrical resistance is to be measured, and means for simultaneously subjecting said indicating means and said article to pulsations of electrical energy, each of which pulsations is capable of performing an amount of Work independent of variations in the voltage impressed upon the circuit.

ll. In electrically operated signaling apparatus, the combination with indicating means including means responsive to pulsations of electrical energy, of mechanism for subjecting said responsive means to pulsations of electrical energy which are each capable of performing an amount of work independent of the E. M. F. producing said puisations, said mechanism comprising a normally immovablrl contact point, a second contact point engageablc With the first-mentioned contact point, and means responsive to said pulsations of electrical energy for causing displacement of said second contact point relative to said first-mentioned contact point.

l2. In electrically operated signaling apparatus, the combination with indicating means including means responsive to pulsations of electrical energy, of mechanism for subjecting said responsive means to pulsations of electrical energy which are each capable of performing an amount of work independent of the E. M. F. producing said pulsations, said mechanism comprising a. normally immovable adjustable contact point, a second contact point engageable with the first-mentioned contact point, and means responsive to said pulsations of electrical energy, for causing displacement of said second contact point relative to said firstmentioned contact point.

13. In electrically operated signaling apparatus, the combination with indicating means including means responsive to pulsations of electrical energy, of mechanism for subjecting said responsive means to pulsations ot electrical energy which are each capable of performing an amount of work independent of the E. M. F. producing said pulsations, said mechanism comprising a movable contact point, means responsive to said pulsations for displacing said contact point, a second movable cont-act point engageable with the first-mentioned contact point, and means responsive to said pulsations of electrical energy for displacing said second contact point.

14. In electrically operated signaling apparatus, the combination With indicating means including means responsive to pulsations ot' electrical energy, oi mechanism for subjecting said responsive means to pulsations of electrical energy which are each capable of performing an amount of Work in dependent of the E. M. F. producing said pulsations, said mechanism comprising a normally immovable contact point, a second contact point engageable With the first-mentioned contact point, means responsive to said pulsations of electrical energy for causing displacement of said contact point relative to said first-mentioned contact point, and means for preventing sparking between said contact points.

l5. In an electrical system, an electrical circuit inciudiug a source of current, electrical circuit conductors and controlling apparatus, said apparatus comprising lvibratory means including a thermostat for opening and closing said circuit to cause pulsations of clcctricai energy to iioyv therethrough, indicating means in said circuit disposed in series with said vibratory means, said vibratory means and said indicatiiwy means being actuated by said pulsations or electrical energy and electrical resistance means in said circuit in series With said vibratory means and in parallel with said indicating means for varying the degree of response of said indicating means according to its resistance value.

16. In an electrical system, an electrical circuit including a source of current, electrical circuit conductors and controlling apparatus, said apparatus comprising vibratory means including a thermostat for opening and closing said circuit to cause pulsations of electrical energy to flow therethrough, electro-responsive means in said circuit disposed in series with said -vibratory means, 'said vibratory means and said electro-respon sive means being actuated by said pulsations of electrical energy, and electrical resistance means in said circuit in series with said vibratory means and in arallel with said elec- .tro-responsive means or varying the degree of response of said electro-responsive means according to its resistance value.

17. In an electrical system, an electrical circuit including a source of current, electrical circuit conductors and controlling apparatus, said apparatus comprising vibratory means including a thermostat for opening and closing said circuit to cause pulsations of electrical energy to fiow therethrough, indicating means in said circuit disposed in series with said vibratory means, said vibratory means and said indicating means being actuated by said pulsations of electrical energy and electrical resistance means in said c1rcuit in series with said vibratory means with said indicating means for ai ying the degree of response of said indicating means according to its resistance value.

18. In an electrical system, an electrical circuit including asource of current, electrical circuit conductors and controlling apparatus, said apparatus comprising vibratory means including a thermostat for opening and closing said circuit to cause pulsations of electrical energy to How therethrough, electro-responsive means in said circuit disposed in series with said Vibratory means, said vibratory means and said electroresponsive means eing actuated by said 40 pulsations of electrical energy, and electrical resistance means in said circuit in series with said vibratory means with said electro-resy insive means for varying the degree of response of said electro-responsive means ac- 45 cording to its resistance value.

In witness whereof, I have hereunto signed my name.

JOHN W. ANDERSON.