Source: http://www.google.com/patents/US7102481?ie=ISO-8859-1
Timestamp: 2015-05-04 03:29:48
Document Index: 127548632

Matched Legal Cases: ['art.\n5', 'art.\n7', 'art 18', 'art 18', 'arts 18', 'art 18', 'arts 28', 'art 28', 'art 28', 'art 28', 'arts 28', 'arts 28']

Patent US7102481 - Low current electric motor protector - Google PatentsSearch Images Maps Play YouTube News Gmail Drive More »Sign inAdvanced Patent SearchPatentsA low current motor protector (10, 10′) has an oblong metal housing (12) defining a switch chamber and formed with an open end. The housing has opposing flange portions extending transversely from the open end. Spaced apart lid portions (18 a, 18 b; 18 a′, 18 b′) are received on and clamped to...http://www.google.com/patents/US7102481?utm_source=gb-gplus-sharePatent US7102481 - Low current electric motor protectorAdvanced Patent SearchPublication numberUS7102481 B2Publication typeGrantApplication numberUS 10/843,101Publication dateSep 5, 2006Filing dateMay 11, 2004Priority dateDec 3, 2003Fee statusPaidAlso published asCN1627586A, CN100456591C, EP1538652A2, EP1538652A3, EP1791150A1, EP1791150B1, US20050122205Publication number10843101, 843101, US 7102481 B2, US 7102481B2, US-B2-7102481, US7102481 B2, US7102481B2InventorsJan J. Stiekel, Young-Hwan ParkOriginal AssigneeSensata Technologies, Inc.Export CitationBiBTeX, EndNote, RefManPatent Citations (24), Referenced by (1), Classifications (16), Legal Events (8) External Links: USPTO, USPTO Assignment, EspacenetLow current electric motor protector
US 7102481 B2Abstract
A low current motor protector (10, 10′) has an oblong metal housing (12) defining a switch chamber and formed with an open end. The housing has opposing flange portions extending transversely from the open end. Spaced apart lid portions (18 a, 18 b; 18 a′, 18 b′) are received on and clamped to the flange portions with an electrically insulating gasket (16) having a central opening interposed between the housing and the lid parts. The lid parts are formed with a recessed ceramic heater seat disposed in the switch chamber having spaced apart contact shelves (18 f) which receives a ceramic heater (20) which is maintained in place and provided with contact force by a spring clip (22, 22′) attached to one of the lid parts. In another embodiment a coil heater (30) is electrically connected between lid parts (28 a, 28 b) and is disposed in a recess formed by a dome configuration (28 f). A thermostatic switch is mounted in the housing and has a movable electrical contact movable into and out of engagement with a stationary electrical contact on one of the lid parts.
a housing member having a longitudinal axis, a bottom wall, a sidewall extending upwardly from the bottom wall defining an open end and a switch chamber, the sidewall having a free end formed with a laterally, outwardly extending flange having portions on at least two opposite sides of the open end,
a lid having first and second spaced apart parts received on the gasket and attached to the housing, at least one of the lid parts formed with a portion having a dome forming a concave configured recess,
an elongated heater element having a generally helical configuration and having first and second end portions, the end portions electrically connected to respective spaced apart lid parts and the helical configuration received in and spaced from the concave configured portion of the lid parts.
2. A motor protector according to claim 1 in which the portion of the lid parts forming the concave configuration extends in both the first and second lid parts.
3. A motor protector according to claim 2 in which the dome extends along the longitudinal axis.
4. A motor protector according to claim 3 in which the dome has a relatively minor longitudinal length in one lid part and a relatively major longitudinal length in the other lid part.
5. A motor protector according to claim 1 in which each lid part has two opposite sides formed with tabs receivable over flange portions of the housing and being clamped to the flange portions through the gasket.
6. A motor protector according to claim 1 including a heater element weld projection formed on each lid part.
7. A motor protector according to claim 6 in which the helical configuration of the heater element extends in a direction generally parallel to the longitudinal axis and the end portions of the heater element extend generally laterally.
This is a continuation-in-part of application Ser. No. 10/727,297 filed Dec. 3, 2003, now U.S. Pat. No. 6,995,647 assigned to the assignee of this invention.
In order to make such protectors quickly responsive to very small current levels, it is also known to provide a supplemental heater mounted in heat transfer relation with the disc. An example of this type of protector is shown and described in U.S. Pat. No. 4,476,452 and comprises a metallic housing having an open end with a flange formed around the open end and a gasket and lid received on and clamped to the housing. A heat responsive electrical switch is disposed in the housing and is adapted to electrically connect and disconnect a current path through the housing and lid upon the occurrence of selected thermal conditions. The lid comprises two discrete, spaced apart portions, one portion having an elongated part extended therefrom to serve as a terminal and the other portion mounting a portion of the switch. A coil heater is electrically and mechanically connected between the spaced apart portions of the lid providing a protector particularly useful for fractional horsepower motors.
Although motor protectors made according to the above referenced patent are suitable for low current applications, there is a need to provide a low cost protector useful for low current applications having even more current sensitivity yet one which is mechanically robust and one which has increased reset times required for certain applications, such as protecting compressor motors.
It is therefore an object of the present invention to provide a low current motor protector which overcomes the above-noted limitations of the prior art. Another object of the invention is the provision of a low current motor protector which has improved current sensitivity, yet is mechanically robust regarding handling and vibration. Yet another object of the invention is the provision of a motor protector of the low current type which can be easily and accurately adapted for use with different electrical devices, such as compressors, transformers and small motors. Yet another object of the invention is the provision of a low current motor protector which is particularly conducive to low cost assembly techniques. Still another object of the invention is the provision of a low current motor protector which has an end of life, open circuit condition.
In another embodiment a coil heater has one end thereof attached to a first of a two part lid clampingly received on the housing through an electrically insulative gasket and a second end thereof attached to the second of the two part lid also clampingly received on the housing through the gasket. The two part lid has a dome configuration formed in a portion of the otherwise generally planar lid parts along with laterally extending tabs adapted to be bent over to clampingly engage the laterally extending flange portions of the housing through the gasket. The coil heater is received in the recess of the dome configuration in heat transfer relation with the thermostatic switch and the two lid parts are spaced longitudinally from each other sufficiently to maintain electrical separation from each other.
FIG. 3 is a blown apart perspective of a motor protector made in accordance with a preferred embodiment of the invention;
FIG. 4 is similar to FIG. 3 of a modified embodiment of the invention but shown without the thermostatic switch;
FIG. 5 is a perspective view of the coil heater embodiment made in accordance with another embodiment of the invention;
FIG. 7 is a top plan view of the FIG. 5 embodiment with the lid parts cut away for the purpose of illustration.
Each lid part is formed with a heater seat in the form of a contact shelf 18 f spaced from the plane in which the respective support portion 18 c, 18 d, lie on the side of the lid parts facing the switch chamber so that the shelves are disposed within the switch chamber 12 d when the lids are placed on the housing. Respective side and back walls 18 g, 18 h are joined to the shelves to ensure a robust seat for maintaining a selected location of a heater element. Shelves 18 f are aligned and face each other and are spaced from each other a selected amount to provide direct, close, radiational heat coupling of a heat element received on the shelves with snap acting thermostatic disc 14 a. A heater element in the form of a ceramic substrate 20 has opposed first and second face surfaces 20 a, 20 b and first and second ends 20 c, 20 d, respectively. An electrical contact layer 20 e of suitable material, such as a silver containing material, preferably formed with external contact bumps, extends across each end 20 c, 20 d on first face surface 20 a and an electrical resistive thick film layer 20 f covered by a glass layer is disposed on the first face surface 20 a extending between and in electrical connection with the contact layers. The contact layers of the ceramic substrate are adapted to be received on ledges 18 f with the ceramic element closely fitting in the recessed seat and with the heater surface facing thermostatic disc 14 a. A stationary electrical contact 21 is mounted preferably on a platform formed in support portion 18 c of lid part 18 a on the side of the lid part having shelf 18 f. Movable contact 14 d is adapted to move into and out of engagement with stationary contact 21 in dependence upon the dished configuration of the thermostatic disc 14 a. A spring clip 22 is formed of suitable material such as stainless steel and generally has an elongated body portion to extend across the width of housing 12 with opposite end portions 22 a bent back on themselves to form a generally V configuration with the body portion and a locking tab 22 b is struck out from each bent over portion with the free end 22 c of the tab extending away from the free end of each locking tab portion 22 b. A force application portion in the form of a projection 22 e extends away from the body portion of clip 22 on the same side of the clip that end portions 22 a are bent to extend.
One terminal 12 f extends from housing 12 and another terminal 18 m extends from lid part 18 b. Once thermostatic switch 14 is mounted in switch chamber 12 d, gasket 16 is slipped onto flange 12 c followed by lid parts 18 a, 18 b with V-shaped tabs 18 e slipped over gasket 16, including portion 16 b. The lid parts are spaced from one another a selected distance sufficient to ensure electrical separation and with ledges 18 f property spaced from each other to receive ceramic substrate 20 thereon with the contact surfaces 20 e received on respective shelves 18 f. Tabs 18 e are then bent inwardly to clamp the lid parts in their selected positions. The ceramic substrate is then inserted and clip 22 is placed over lid portion 18 b so that end portions 22 a are received over-tabs 18 e and with struck out locking tab 22 b received under respective catch surfaces 18 k and with force application portion 22 e placing a force on face 20 b of ceramic substrate 20.
FIG. 4 shows a modified embodiment 10′ in which catch surfaces 18 k are formed in lid portion 18 a′ and clip 22′ is formed with a leg portion 22 f for positioning force application projection 22 e′ so that it will be aligned with the center of ceramic substrate 20 when clip 22′ is attached to lid part 18 a′. Leg 22 f may be bent upwardly, as shown in the drawing, for example, along dashed line 18 g, to provide a suitable bias to the ceramic substrate.
With reference to FIGS. 5�7, another embodiment 100 of the invention is shown comprising an oblong metal housing 12, as shown in the previous embodiments. Housing 12 has bottom wall 12 a, side walls 12 b extending from the bottom wall, a flange 12 c extending laterally outwardly from the free end of at least portions of the sidewalls along with a terminal 12 f extending longitudinally from flange 12 c at one end of the housing.
A thermostatic switch (not shown) of the type shown in FIG. 3 is received in a switch chamber 12 d, the thermostatic disc member preferably mounted on platform 12 e of bottom wall 12 a. Electrically insulating gasket 16 is received on and covers flange 12 c of the housing, again as in the previously described embodiments.
A lid 28 of electrically conductive material comprises first and second parts 28 a, 28 b, respectively. Each lid part has a flat support portion 28 c, 28 d, respectively, lying in a plane for reception on the frame gasket portion 16 a and flange 12 c and opposed tabs 28 e bent inward toward the center of the respective lid part forming a generally V configuration with the support portions, as in the previously described embodiments. A stationary contact platform 28 m and a terminal 28 n are formed on lid part 28 a. A dome shaped configuration 28 f is formed in the flat support portion of the lids which extends in a direction generally parallel to the longitudinal axis 2 of oblong housing 12. As shown, dome 28 f has a first, relatively minor, longitudinal length portion 28 g in first lid part 28 a and a second, relatively major, longitudinal length portion 28 h in second lid part 28 b. As best seen in FIG. 7, lid parts 28 a, 28 b preferably have a wider flat support surface on one side of the longitudinal axis 2 of the lid to facilitate placement of weld projections 28 j, 28 k on respective lid parts while maximizing the available longitudinal space available for the helical configuration of the heater, to be discussed. The weld projections can be formed by local deformation of the flat support portions or by placement of weld slugs, as desired. The wall of dome configuration 28 f is formed with a cut-out aligned with each weld projection to allow an end of a coil heater to pass through for attachment thereto.
A helical or coil heater 30 has a first end 30 a and a second end 30 b attached to respective weld projections 28 j, 28 k, as by welding with the helical portion of the heater disposed within the concave recess formed by the dome configuration in direct thermal communication with the thermostatic switch received in housing 12. Lid parts 28 a, 28 b, are clamped to housing 12 by means of tabs 28 e with the lid parts spaced from one another along longitudinal axis 2 enough to provide suitable electrical separation between the two lid parts but otherwise close enough to effectively form an enclosure to retain heat generated by the coil heater for an extended period and thereby extend the off or reset time of the thermostatic switch. Dome configuration 28 f also serves to protect the coil heater during handling and the like.
Patent CitationsCited PatentFiling datePublication dateApplicantTitleUS3095486 *Jul 14, 1960Jun 25, 1963Texas Instruments IncMiniaturized printed circuit electrical switching deviceUS3430177 *Dec 30, 1966Feb 25, 1969Texas Instruments IncMiniature thermostatic switchUS3622930 *Oct 16, 1969Nov 23, 1971Texas Instruments IncMotor protector apparatus and methodUS3753195 *Sep 20, 1972Aug 14, 1973Gen ElectricThermostatic switchUS4015229 *Jan 10, 1975Mar 29, 1977Texas Instruments IncorporatedThermally responsive switchUS4086558 *Feb 9, 1976Apr 25, 1978Texas Instruments IncorporatedMotor protector and systemUS4136323 *Jun 1, 1977Jan 23, 1979Entremont John R DMiniature motor protectorUS4224591 *Dec 4, 1978Sep 23, 1980Texas Instruments IncorporatedMotor protector with metal housing and with preformed external heater thereonUS4399423 *Mar 29, 1982Aug 16, 1983Texas Instruments IncorporatedMiniature electric circuit protectorUS4476452Sep 27, 1982Oct 9, 1984Texas Instruments IncorporatedMotor protectorUS4490704 *Sep 14, 1983Dec 25, 1984Therm-O-Disc, IncorporatedThermally responsive switching deviceUS4646195 *Oct 11, 1984Feb 24, 1987Texas Instruments IncorporatedMotor protector particularly suited for use with compressor motorsUS5206622 *Apr 10, 1992Apr 27, 1993Texas Instruments IncorporatedProtector device with improved bimetal contact assembly and method of makingUS5615072 *Aug 9, 1995Mar 25, 1997Thermik Geratebau GmbhTemperature-sensitive switchUS5808539 *Aug 28, 1997Sep 15, 1998Texas Instruments IncorporatedTemperature responsive snap acting control assembly, device using such assembly and method for makingUS5936510 *May 22, 1998Aug 10, 1999Portage Electric Products, Inc.Sealed case hold open thermostatUS5973587 *Jun 25, 1998Oct 26, 1999Hofsaess; MarcelTemperature-dependent switch having a contact bridgeUS6020807 *Feb 23, 1999Feb 1, 2000Portage Electric Products, Inc.Sealed case hold open thermostatUS6744345 *May 6, 2002Jun 1, 2004Cooper TechnologiesMid-range circuit breakerUS6756876 *Aug 1, 2002Jun 29, 2004Texas Instruments IncorporatedCircuit interrupter and methodUS6801116 *Jun 18, 2003Oct 5, 2004Texas Instruments Korea LimitedOverload protector with hermetically sealing structureUSD281240 *Mar 16, 1983Nov 5, 1985Portage Electric Products, Inc.Housing for a thermostatic switchUSD336072 *Jul 23, 1991Jun 1, 1993Portage Electric Product, Inc.Housing for a thermostatic switchJP2005108585A * Title not available* Cited by examinerReferenced byCiting PatentFiling datePublication dateApplicantTitleUS20110025449 *Jul 30, 2010Feb 3, 2011Stefan GrosskopfBi-metal snap action disc* Cited by examinerClassifications U.S. Classification337/107, 337/112, 337/102International ClassificationH02P29/02, H01H37/54, H01H37/02, G01K5/64, H01H61/02, H01H37/04, H01H37/14, H01H37/52Cooperative ClassificationH01H37/5418, H01H37/5427, H01H61/02European ClassificationH01H61/02, H01H37/54CLegal EventsDateCodeEventDescriptionFeb 25, 2014FPAYFee paymentYear of fee payment: 8May 17, 2011ASAssignmentOwner name: SENSATA TECHNOLOGIES MASSACHUSETTS, INC., MASSACHUFree format text: RELEASE BY SECURED PARTY;ASSIGNOR:MORGAN STANLEY & CO. INCORPORATED;REEL/FRAME:026293/0352Effective date: 20110512Effective date: 20110512Owner name: SENSATA TECHNOLOGIES, INC., MASSACHUSETTSFree format text: RELEASE BY SECURED PARTY;ASSIGNOR:MORGAN STANLEY & CO. INCORPORATED;REEL/FRAME:026293/0352Free format text: RELEASE BY SECURED PARTY;ASSIGNOR:MORGAN STANLEY & CO. INCORPORATED;REEL/FRAME:026293/0352Effective date: 20110512Owner name: SENSATA TECHNOLOGIES FINANCE COMPANY, LLC, MASSACHFeb 19, 2010FPAYFee paymentYear of fee payment: 4Aug 28, 2008ASAssignmentOwner name: MORGAN STANLEY & CO. INCORPORATED, NEW YORKFree format text: SECURITY AGREEMENT;ASSIGNOR:SENSATA TECHNOLOGIES MASSACHUSETTS, INC.;REEL/FRAME:021450/0563Effective date: 20080430May 29, 2008ASAssignmentOwner name: SENSATA TECHNOLOGIES MASSACHUSETTS, INC., MASSACHUFree format text: ASSIGNMENT OF ASSIGNORS INTEREST;ASSIGNOR:SENSATA TECHNOLOGIES, INC.;REEL/FRAME:021018/0690Effective date: 20080430Jun 22, 2006ASAssignmentOwner name: SENSATA TECHNOLOGIES, INC., MASSACHUSETTSFree format text: ASSIGNMENT OF ASSIGNORS INTEREST;ASSIGNOR:TEXAS INSTRUMENTS INCORPORATED;REEL/FRAME:017870/0147Effective date: 20060427May 5, 2006ASAssignmentOwner name: MORGAN STANLEY & CO. INCORPORATED, NEW YORKFree format text: SECURITY AGREEMENT;ASSIGNORS:SENSATA TECHNOLOGIES, INC.;SENSATA TECHNOLOGIES FINANCE COMPANY, LLC;REEL/FRAME:017575/0533Effective date: 20060427Jul 19, 2004ASAssignmentOwner name: TEXAS INSTRUMENTS INCORPORATED, TEXASFree format text: ASSIGNMENT OF ASSIGNORS INTEREST;ASSIGNORS:STIEKEL, JAN J.;PARK, YOUNG-HWANG;REEL/FRAME:015573/0236Effective date: 20040628RotateOriginal ImageGoogle Home - Sitemap - USPTO Bulk Downloads - Privacy Policy - Terms of Service - About Google Patents - Send FeedbackData provided by IFI CLAIMS Patent Services