US3271546A

US3271546A - Pendulum actuated tilt responsive electric switch

Info

Publication number: US3271546A
Application number: US352226A
Authority: US
Inventors: Amos E Chesnut
Original assignee: Arvin Industries Inc
Current assignee: Meritor Inc
Priority date: 1964-03-16
Filing date: 1964-03-16
Publication date: 1966-09-06
Anticipated expiration: 1983-09-06

Description

p 6, 1955 A. E. CHESNUT 3,271,546

PENDULUM ACTUATED TILT RESPONSIVE ELECTRIC SWITCH Filed March 16, 1964 2 Sheets-Sheet 1 INVENTOR/ Fa. W haw/1 2 Sheets-Sheet 2 a A W w f a l a, I Z i Z A 7 J A I 1/ a 1 J r a Z /0 Z M m ME? )1 7 .N n :nf 4

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Sept. 6, 1966 A. E. CHESNUT PENDULUM ACTUATED TILT RESPONSIVE ELECTRIC SWITCH Filed March 16, 3.964

United States Patent M 3,271,546 PENDULUM ACTUATED TILT RESPONSIVE ELECTRIC SWITCH Amos E. Chesnut, Columbus, Ind., assignor to Arvin Industries, Inc., Columbus, Ind, a corporation of Indiana Filed Mar. 16, 1964, Ser. No. 352,226 9 Claims. (Cl. 200-133) This invention relates to an electric switch, and more particularly to a combined thermostat and tip-over switch for use in an electric appliance or the like.

It is an object of the invention to provide an electric switch which will be responsive to thermal actuation, which will be actuated by the relative movement of a gravity actuated safety control member, which will require the use of but one pair of contacts, which can be mounted in different orientations within an appliance, which can be simply and inexpensively manufactured from a relatively small number of par-ts, and which can be of a compact size.

In accordance with one form of the invention as it is embodied in a combined thermostat and safety switch, there is provided an insulating base. First and second metallic blades are fixedly mounted at one of their ends on said base and are provided adjacent their opposite ends with first and second contacts engageable with each other for completing a circuit through said blades. A bimetallic blade is also mounted on said base and is engageable with said first blade to thus vary the position of the contacts with respect to each other and in response to temperature changes.

A rigid gene-rally L-shaped arm is mounted on the base and is provided with a pair of outwardly projecting win-gs which may conveniently serve as mounts for mounting the switch on an appliance. A screw is adjustably mounted in said arm and projects through an opening in said first blade to engage the second blade for varying the position of the blade contacts to provide calibrated adjustment of the temperature of actuation of said contacts.

A gravity actuated safety control member is mounted on said arm. The control member is in the form of a pendulum comprising a first portion of electrically insulating material swingably connected to said arm and a weighted second portion projecting downwardly from said first portion. The pendulum is gravity actuated and the switch is mounted at an attitude wherein the pendulum will hang vertically with its first portion out of engagement Wit-h said first and second blades. Upon tilting of the switchin either direct-ion in a plane parallel to the plane of said first portion, said switch will move relative to the pendulum to cause said first portion to engage first blade and the arm to move the contacts out of engagement with each other to thus open the circuit through the switch. Upon movement of the switch into its normal orientation, said pendulum will again hang vertically in a position to dispose said first portion out of engagement with the first blade for restoring the contacts in their operative position.

Other objects and features of the invention will become apparent from the more detailed description which follows and from the accompanying drawings, in which:

FIG. 1 is a vertical section through an electric heater having a switch embodying the invention mounted therein;

FIG. 2 is an enlarged plan view of the switch shown in FIG. 1;

FIG. 3 is an end elevation of the switch shown in FIG. 2 and showing said switch in a tilted orientation;

FIG. 4 is an end elevation similar to FIG. 3, but showing the switch in a different tilted orientation;

FIG. 5 is a perspective view of the safety control pendulum shown in FIG. 2;

3,271,546 Patented Sept. 6, 1966 FIG. 6 is an end elevation of the switch shown in FIG. 2, but showing a modified form of the safety control pendulum; and

FIG. 7 is a side elevation of the switch shown in FIG. 6.

As shown in the drawings, the switch comprises a base 10 formed from a plurality of insulating blocks 12 retained in a stacked position by a bolt 14. First and second resilient metallic blades 15 and 16 have one of their ends mounted on the base 10 and separated by one of the blocks 12 to electrically insulate said blades from each other. Desirably, said blades are provided with

terminals

17 and 18 for connecting them to appropriate electrical leads. The blades project outwardly from the base 10 and

contacts

20 and 21 are mounted on the blades 15 and 16, respectively, adjacent their ends remote from said base. The blades 15 and 16, due to their inherent resiliency, are urged toward each other toward a contact closing position. A bimetallic blade 22 electrically insulated from the blade 16 by one of the blocks 12 is also mounted on the base 10. The outer end of the blade 22 is bent to engage the blade 15 for thus causing the

contacts

20 and 21 to be moved into and out of engagement with each other in response to temperature changes.

A rigid generally L-shaped arm 24 is mounted on the base 10 and comprises a first stretch 26 generally normal to a second stretch 28. On end of the stretch 26 is connected to said base in an insulate-d position from the blade 15 by one of the blocks 12. Said stretch extends outwardly from the base and is provided with a pair of outwardly projecting wings 30' which serve as mounts for mounting the switch on a heater or other appliance as is shown in FIG. 1. The arm stretch 26 is provided with a threaded boss 34 in which an adjusting screw 36 is carried. The switch shown in FIGS. l-3 is adapted to be mounted in a heater or other appliance in a vertical orientation with the blades 15 and 16 lying in generally vertical planes. In such an orientation in a heater, the screw 36 projects outwardly through the forward heater face 37 shown in FIG. 1 and is connected to a control knob 38. The opposite end of said screw comprises an insulator tip 40 which projects through an opening 42 in the blade 15 and bears against the blade 16. Conveniently, the blade 16 may be dented, as at 44, for locating the tip 40 against said blade. The knob 38 may be moved in front of indicia (not shown) on the heater face 37 to thus provide calibrated adjustment of the temperature of actuation of

contacts

20 and 21. Conveniently, a finger 46 is struck outwardly from one of the wings 30 in the path of rotation of a lug 48 mounted on the screw 36 to limit rotational movement of said screw and thus limit the positioning of contact 21 with respect to contact 20 upon rotation of said screw. The finger 46 also carries a loop spring 50 bindingly embracing the screw 36 for frictionally retarding rotation of said screw and thereby serving to hold the screw in the desired position of adjustment.

A safety member in form of a pendulum is swingably mounted on the arm stretch 28. Said pendulum corn prises an elongated first portion '52 of electrically insulating material having a pair of recesses 54 formed along one of its longitudinal edges inwardly from the ends thereof. The recesses 54- thus provide the portion 52 with a pair of end projections 55 and 56 and an intermediate third projection 57. An opening 58 is formed in the region of the projection 57 for the reception of a pivot pin 60 mounted on the arm stretch for supporting the pendulum on the arm 24 for swinging movement relative to the switch in a plane generally normal to the plane of the blades 15 and 16. The pendulum has a second portion in the form of a weight 62 mounted on one end of the portion 52 and projecting downwardly from the portion 52 in alignment therewith. When the switch is mounted in an appliance with the

blades

15, 16, and 22 in generally vertical planes, the pendulum will hang downwardly from its connection 60 to the arm 24-. With the appliance in its normal upright position, said pendulum will be disposed out of contact with the blades 15 and 16, and opening and closing of the

contacts

20 and 21 will be in response solely to movement of the bimetal blade 22 against the arm 15 and the adjustment provided by the screw tip 40 bearing against blade 16. However, as shown in FIG. 3, when the appliance is tilted rearwardly, the switch will move from its normal upright position shown in FIG. 1 to a tilted position shown in FIG. 3, but the pendulum will maintain its vertical orientation due to the weight 62. When the switch is so tilted, the projection 57 will bear against and move the blade 15 to open the

contacts

20 and 21, and the projection 55 will bear against the upper edge of the arm stretch 26 to thus limit movement of the blade 15 in a contact opening direction and prevent said blade from being permanently bent and distorted. Conversely, as shown in FIG. 4, when the appliance is tilted forwardly, the .switch likewise tilts forwardly from its normal vertical orientation, and the projection 57 will again engage and move the blade 15 to move the contact 20 out of engagement with the contact 21, and the projection 56 will engage the lower edge of the arm stretch 26 to limit the movement of blade 15 in its contact opening direction.

The switch shown in FIGS. l-3 is adapted to be mounted in an appliance in a vertical orientation wherein the

blades

15, 16, and 22 lie in generally vertical planes. However, in certain instances it is necessary that the switch be mounted in a horizontal orientation wherein the

blades

15, 16, and 22 lie in generally horizontal planes. In order to permit my switch to be mounted in such a horizontal orientation, I employ the pendulum construction shown in FIGS. 6 and 7.

The switch shown in FIGS. 6 and 7 differs from the the contact 21, and the projection 66 will bear against the lefit edge of the arm stretch 26 to limit such blade movement.

With the blade in each embodiment projecting outwardly beyond the blade 22 for engagement with the

pendulum

52 or 64 when the switch is tilted, said pendulums further serve to provide a positive off for the switch when it is in its normal upright position. When the thermostat is in its fully off position, the blade 16 is in a position to cause the

contacts

20 and 21 to be spaced from each other, but the end of the bimetal blade 22 will still contact the blade 15. However, should the ambient temperature drop below the temperature for base and respectively having first and second contacts adjacent their opposite ends, a bimetallic blade mounted on said base and engageable with one of said first and second blades to vary the position of said contacts with respect to each other, a rigid generally L-shaped arm mounted on said base, a screw adjustably mounted on switch in FIGS. l 3 only in the construction of the pendulum. To this end, said switch comprises first and second resilient metallic blades 15 and 16 mounted on an insulating base 10 and carrying

contacts

20 and 21. A bimetallic blade 22 is also mounted on the base 10 and is engageable with the blade 15 for opening and closing the

contacts

20 and 21 in response to temperature changes. The switch is mountable in an appliance by a rigid generally L-shaped arm 24 comprising a first stretch 26 connected to the base 10 and integral with a second stretch 28. The stretch 26 carries an adjusting screw 36 having a control knob 38 at one of its ends and an insulator tip 40 at its opposite end engageable with the blade 16 for adjusting the relative positioning of the

contacts

20 and 21.

The switch shown in FIGS. 6 and 7 is mounted in a horizontal orientation with the arm stretch 28 projecting downwardly. Said stretch is connected by a pin 63 to a generally T-shaped pendulum comprising an elongated first portion 64 formed from electrically insulating material. The upper edge of the first portion 64 has a pair of recesses 65 spaced inwardly from the ends thereof to define a pair of end projections 66 and 67 and an elongated third projection 68 intermediate the projections 66 and 67 and swingably connected to the pin 63. A shank 70 projects downwardly from the first portion 64 intermediate to the length thereof and is connected to a weight 72 to thus cause the first portion 64 to be suspended in a generally horizontal orientation.

Should the switch and the appliance to which it is connected be tilted to the left as viewed in FIG. 6, the 7 said arm and engageable with one of said first and second blades to vary the position of said contacts relative to each other, and a pendulum having a first portion of electrically insulating material swingably connected to said arm, and a weighted second portion, said pendulum being gravity actuated and said switch being mounted in an attitude wherein said pendulum will 'hang ventically with said first portion out of engagement with said first and second blades, said first portion being engageable with one of said first and second blades upon tipping of the switch in either direction in a plane generally parallel to the plane of said first portion to cause said first portion to move one of said first and second blades relative to the other to move said contacts into spaced relation to each other.

2. The invention as set forth in claim 1 in which said pendulum is swingable relative to said arm in a plane generally normal to the planes of said first and second blades.

3. An electric switch, comprising a base, first and second blades fixedly mounted at one of their ends on said base and respectively having first and second contacts adjacent their opposite ends, a bimetallic blade mounted on said base and engageable with one of said first and second blades to vary the position of said contacts with respect to each other, a rigid arm having a first stretch mounted on said base and a second stretch normal to said first stretch, a screw adjustably mounted in said first stretch and engageable with one of said first and second blades to vary the position of said contacts relative to each other, and a pendulum having a first portion of electrically insulating material swingably connected to said second stretch and a weighted second portion, said pendulum being gravity actuated and said switch being mounted in an attitude wherein said pendulum will hang vertically with said first portion out of engagement with said first and second blades, said first portion being engageable with one of said first and second blades upon tipping of the switch in either direction in a plane generally parallel to the plane of said first portion to cause said first portion to move one of said first and second blades relative to the other to move said contacts into spaced relation to each other.

4. An electric switch, comprising a base, first and second blades fixedly mounted at one of their ends on said base and respectively having first and second contacts adjacent their opposite ends, a rigid arm mounted on said base, and a pendulum having a first portion of electrically insulating material having first and second sets of cam elements swingably connected to said arm and a weighted second portion, said pendulum being gravity actuated and said switch being mounted in an attitude wherein said pendulum will hang vertically with said first portion out of engagement with said first and second blades, the first set of cam elements on said first portion being engageable with one of said first and second blades upon tipping of the switch in either direction in a plane generally parallel to the plane of said first portion to cause said first portion to move one of said first and second blades relative to the other to move said contacts into spaced apart relation to each other and said second set of cam elements limiting the movements of said blades relative to each other upon said tipping.

5. The invention as set forth in claim 4 in which said first portion of said pendulum has a pair of recesses spaced inwardly from its ends along one side thereof to define a pair of projections at its opposite ends constituting said second set of cam elements and a third projection intermediate its length areas of which constitute said first set of cam elements, said first portion being swingably connected to said arm in the region of said third projection whereby one cam element in said first set of cam elements and one cam element in said second set of cam elements engage said first blade and arm, respectively, when the switch is tilted in one direction and the other cam element in said first set of cam elements and the other cam element in said second set of cam elements engage said first blade and arm, respectively, when the switch is tilted in an opposite direction.

6. The invention as set forth in claim 5 in which said weighted second portion of the pendulum extends downwardly from one end of said first portion in longitudinal alignment with said first portion.

7. The invention as set forth in claim 5 in which said weighted second portion of the pendulum extends downwardly from said first portion intermediate the length of said first portion and said pendulum is generally T-shaped.

8. An electric switch, comprising a base, first and second blades fixedly mounted at one of their ends on said base and having their opposite ends biased toward each other and provided with first and second contacts, respectively, a bimetallic blade mounted on said base and engageable with said first blade to vary the position of said contacts with respect to each other, a rigid generally L- shaped arm mounted on said base, a screw adjustably mounted on said arm and engageable with said second blade to vary the position of said contacts relative to each other, and a pendulum having a first portion of electrically insulating material swingably connected to said arm,

and a weighted second portion, said pendulum being gravity actuated and said switch being mounted in an attitude wherein said pendulum will hang vertically with said first portion out of engagement with said first and second blades, said first portion being engageable with said first blade and arm upon tipping of the switch in either direction in a plane generally parallel to the plane of said first portion to cause said first portion to move said first blade relative to said second blade to move said contacts into spaced relation to each other, said pendulum being spaced relative to said first blade when the switch is in its upright position and said screw has moved the second blade into a position to provide maximum spacing between the contacts to prevent said first blade from moving said first contact into engagement with the second contact irrespective of the movement of said bimetallic blade.

9. An electric switch, comprising a base, first and second blades fixedly mounted at one of their ends on said base and respectively having first and second contacts adjacent their opposite ends, a rigid arm mounted on said base, and a pendulum having a first portion of electrically insulating material swingably connected to said arm and a weighted second portion, said pendulum being gravity actuated and said switch being mounted in an attitude wherein said pendulum will hang vertically without said first portion eflecting movement of either of said blades, said first portion being engageable with one of said first and second blades and arm upon tipping of the switch in either direction in a plane generally parallel to the plane of said first portion to cause said first portion to move one of said first and second blades relative to the other to move said contacts into spaced relation to each other, said arm and pendulum having co-operating means for limiting the relative movement between said arm and pendulum.

References Cited by the Examiner UNITED STATES PATENTS 2,297,095 9/1942 Bassett 200-61.48 2,313,549 3/1943 Hornain 200-61.48 2,768,256 9/1956 Barccki et al. 20061.48 2,831,090 4/1958 Kueser 20013'8 2,897,320 7/1959 Patti 200-138 3,114,812 12/1963 'Levinn 200138 3,201,548 8/1965 Mertler 200138 FOREIGN PATENTS 322,594 11/1934 Italy.

BERNARD A. GILHEANY, Primary Examiner. L. A. WRIGHT, T. D. MACBLAIN, Assistant Examiners.

Claims

1. AN ELECTRIC SWITCH, COMPRISING A BASE, FIRST AND SECOND BLADES FIXEDLY MOUNTED AT ONE OF THEIR ENDS ON SAID BASE AND RESPECTIVELY HAVING FIRST AND SECOND CONTACTS ADJACENT THEIR OPPOSITE ENDS, A BIMETALLIC BLADE MOUNTED ON SAID BASE AND ENGAGEABLE WITH ONE OF SAID FIRST AND SECOND BLADES TO VARY THE POSITION OF SAID CONTACTS WITH RESPECT TO EACH OTHER, A RIGID GENERALLY L-SHAPED ARM MOUNTED ON SAID BASE, A SCREW ADJUSTABLY MOUNTED ON SAID ARM AND ENGAGEABLE WITH ONE OF SAID FIRST AND SECOND BLADES TO VARY THE POSITION OF SAID CONTACTS RELATIVE TO EACH OTHER, AND A PENDULUM HAVING A FIRST PORTION OF ELECTRICALLY INSULATING MATERIAL SWINGABLY CONNECTED TO SAID ARM, AND A WEIGHTED SECOND PORTION, SAID PENDULUM BEING GRAVITY ACTUATED AND SAID SWITCH BEING MOUNTED IN AN ATTITUDE WHEREIN SAID PENDULUM WILL HANG VERTICALLY WITH SAID FIRST PORTION OUT OF ENGAGEMENT WITH SAID FIRST AND SECOND BLADES, SAID FIRST PORTION BEING ENGAGEABLE WITH ONE OF SAID FIRST AND SECOND BLADES UPON TIPPING OF THE SWITCH IN EITHER DIRECTION IN A PLANE GENERALLY PARALLEL TO THE PLANE OF SAID FIRST PORTION TO CAUSE SAID FIRST PORTION TO MOVE ONE OF SAID FIRST AND SECOND BLADES RELATIVE TO THE OTHER TO MOVE SAID CONTACTS INTO SPACED RELATION TO EACH OTHER.