MXPA01010660A - Cassette assembly with rejection features - Google Patents

Abstract

A cassette assembly for rotary contact circuit breakers utilizing a first electrically insulative cassette half piece and a second electrically insulative cassette half piece which are arranged to mate with each other to form an enclosure. The electrically insulative cassette half pieces include improper installation rejection features for both the rotor and arc chute assemblies. The inner surface of a electrically insulative cassette half piece including a groove and recesses formed therein. A rotor is properly positioned within the electrically insulative cassette half piece by inserting a pin on the face of the rotor into the groove. An arc chute assembly is properly positioned within the electrically insulative cassette half piece by inserting a tab located on a side member of the arc chute assembly into a corresponding recess located in the electrically insulative cassette half piece.

Description

CARTRIDGE UNIT WITH REJECTION CHARACTERISTICS BACKGROUND OF THE INVENTION This invention relates in general to a circuit breaker and in particular to a cartridge unit of the circuit breaker. Circuit breakers are a variety of overcurrent protective devices used for the protection and isolation of circuit breakers. The basic function of a circuit breaker is to provide protection to the electrical system whenever an electrical abnormality occurs in any part of the system. In a rotary contact circuit breaker, current enters the system from a power line. The current passes through a charging belt towards a stationary contact fixed on the belt and then towards a moving contact. The movable contact is fixedly coupled with an arm, and the arm is mounted on a rotor, which in turn is mounted rotatably on a cartridge. Whenever the fixed contacts are in physical contact with the moving contacts, the current passes from the fixed contacts to the moving contacts and away from the circuit breaker to the terminal electrical devices. In case of an overcurrent condition (for example, a short circuit), extremely high electromagnetic forces are generated. These electromagnetic forces repel mobile contact away from their stationary contact. Because the movable contact is fixedly coupled with a rotating arm, the arm is mounted by pivots and physically separates the movable and stationary contacts, whereby the unit is disconnected. When the contacts open quickly as in the case during a disconnection caused by short circuit event, an arc is produced. The extinction of the arc displacement usually involves recourse to pneumatic or electromagnetic means to motivate the arc, in order to increase its trajectory length, promote the removal of the arc from the switch contacts, and facilitate the cooling and division of the arc, all contributing to increase the arc voltage to a value in excess of the drive voltage of the system. When the arc voltage exceeds the voltage of the source, it is difficult for the arc voltage to maintain the arc voltage so that the arc is extinguished. Accordingly, a voltage corresponding to the voltage of the source between the stationary contact and the moving contact is presented, which carries out the operation of the circuit breaker. A common practice is to employ an arc blow box unit to extinguish this resulting arc. Such arc-blow box units consist of a plurality of metal plates of the blow box which is maintained in a stacked relation, separated by the side panels which are made of electrically non-conductive material. The retention of the plates of the blow box between the side panels is usually achieved by providing the plates with small protuberances that slide within a series of notches with radius on the side panels. The design of the circuit breaker, and more particularly the design of the cartridge, should allow for the proper and effective placement of the different components, such as the rotor and the arc blow box units, inside the cartridge. For example, improper installation of a rotor inside the cartridge can result in two half pieces of the cartridge that do not match correctly together. Also, care must be taken that the arc-blow box is correctly placed inside the cartridge. This ensures adequate rotation of the movable contact arm as well as adequate separation between the movable contact and the plate closest to the movable contact. Improper installation of either the rotor or the arc blow box unit within the half-piece of the cartridge will require the disassembly and reassembly of the cartridge. Such disassembly and reassembly operations are time consuming and can increase the production cost of the circuit breaker.

BRIEF DESCRIPTION OF THE INVENTION In an exemplary embodiment of the invention, a cartridge unit suitable for use with a rotary contact circuit breaker includes a first electrically insulating half-piece of the cartridge having an internal surface with a first recess and a groove. formed therein and a second half piece of the electrically insulating cartridge having an inner surface with a third recess formed therein. The second half piece of the electrically insulating cartridge is arranged to match the first half piece of the electrically insulating cartridge. The first and second arc blow box units are arranged between the first and second half-pieces of cartridge, electrically insulating. A first arc blow box unit includes a first side member, a second side member, a tongue and a plurality of plates disposed between the first and second side members and arranged in a separate, stacked relationship. The tongue extends from the first side member and through the first recess to properly place the first arc-blow box unit in the first half-piece of the electrically insulating cartridge. A second arc-blow box unit includes a third side member, a fourth side member, a tongue and a plurality of plates disposed between the third and fourth side members and arranged in a separate relationship. The tongue extends from the third side member and through the third recess to properly place the second arc-blow box unit in the first half-piece of the electrically insulating cartridge.

BRIEF DESCRIPTION OF THE DRAWINGS Figure 1 is a front perspective view of a rotary cartridge unit of the circuit breaker; Figure 2 is a view of the first half-piece of the electrically insulating cartridge of the cartridge unit of the present invention showing the reject characteristics; Figure 3 is a view of the second half-piece of the electrically insulating cartridge of the cartridge unit of the present invention showing the reject characteristics; Figure 4 is a view of a rotor used in the electrically insulating half-pieces of the cartridge of Figures 2 and 3; Figure 5 is a top view of an arc blow box unit positioned in the electrically insulating half-pieces of the cartridge of Figures 2 and 3; and Figure 6 is a view of a side member of the arc blowing box used in the arc blowing box unit of Figure 5.

DETAILED DESCRIPTION OF THE INVENTION With reference to Figure 1, a rotary contact unit 12 is shown in a unit 10 of the circuit breaker cartridge in a first half piece 14 of the cartridge, electrically insulating, intermediate to the side contact strap 16 in line, the lateral load contact strap 18 and the associated arc blow boxes 20, 22. The on-line side contact strap 16 is electrically connected to the in-line side wiring (not shown) in an electrical distribution circuit, and the side load contact strap 18 is electrically connected to the side load wiring (not shown) through a seat (not shown) or some device such as a bimetallic element or current detector (not shown). The electrically insulating shells 24, 26 separate the side-loading contact strap 18 and the line-side contact strap 16 from the associated arc-blowing box units 20, 22, respectively. Although only one rotary contact unit 12 is shown, it should be understood that a separate rotary contact unit 12 is employed within each pole of the multi-pole circuit breaker and operates in a similar manner. The electrical transport through the interior of the circuit breaker comes from the lateral contact strap 16 in line with the first contacts 2830 mobile and fixed at one end of a mobile contact arm 32, towards the first contacts 34, 36 mobile and fixed at the opposite end thereof, towards the side load contact strap 18. The movable contact arm 32 is arranged between the two halves of a circular rotor 37. The movable contact arm 32 moves in unison with the rotor 37 under the manual articulation of the operating mechanism of the circuit breaker (not shown) to drive the first and second contacts 30, 36 movable between the CLOSED positions (illustrated in FIG. Figure 1) and OPEN. A first contact spring 38 extends between a pair of spring pins 40, 42 within the slot 48 of the contact spring formed within one side of the rotor 37 and a second contact spring (not shown) extends between the pins 40, 42 in a similar manner on the opposite side of the rotor 37.

The arc blowing box units 20, 22 are placed in the first half piece of the electrically insulating cartridge, adjacent to the respective pairs of first fixed and movable contacts 28, 30 and second mobile and fixed contacts 34, 36. The first and second movable contacts 30, 36 and the movable contact arm 32 move through a passage provided by the arc blowing box units 20, 22, in order to be coupled and uncoupled from the first and second contacts. 28, 34 fixed, respective. Each arc blowing box unit 20, 22 is adapted to interrupt and extinguish the arc that is formed when a circuit breaker is disconnected and the first and second movable contacts 30, 36 are suddenly separated from the first and second contacts 28, 34 fixed. With reference to Figure 2, a first half piece 14 of the cartridge is shown, electrically insulating. The first half piece 14 of the electrically insulating cartridge has an internal surface 52 having a first recess 56 and a second recess 54 formed therein. A groove 58 is also formed in the inner surface 52 of the first half-piece 14 of the electrically insulating cartridge. A recess 86 of the rotor is also formed on the inner surface 52. The recesses 88, 90 of the blow box are formed on the inner surface 52 at the opposite ends of the recess 86 of the rotor. The side-on-line and side-loading contact strap recesses 92, 94 are also formed on the inner surface 52 close to the recesses 88, 90 of the arc-blow box. With reference to Figure 3, a second half piece 60 of the cartridge is shown, electrically insulating before being coupled with the first half piece 14 of the cartridge, electrically insulating (Figure 2) to form a complete box. The second half piece 60 of the electrically insulating cartridge has an inner surface 62. The internal surface 62 has a third recess 64 and a fourth recess 66 formed therein. The second half-piece 60 of the electrically insulating cartridge is coupled to the first half-piece 14 of the electrically insulating cartridge (Figure 2) by means of a mechanical fastening means. A recess 86 of the rotor is also formed on the inner surface 62. The recesses 88, 90 of the blow box are formed on the inner surface 62 at the opposite ends of the recess 86 of the rotor. The recesses 92, 94 of the side-on-line and side-loading belt are also formed on the inner surface 62 close to the recesses 88, 90 of the arc-blow box. With reference to Figure 4, a circular rotor 37 is shown before being placed on the first, half-piece 14 of the electrically insulating cartridge (Figure 2). The rotor 37 is supported rotatably by an arrow (not shown) mounted axially and rotatably within the first half-piece 14 of the cartridge, electrically insulating (Figure 2). One or more rotor springs (not shown) are placed in the slots 33 in the face 19. The slots 33 contain slots 39 disposed along the slots 33 to accommodate the pins (not shown) on which the springs are mounted. (not shown). A pivot pin 25 extends from the central portion of the movable contact arm 32 to the central portion of the rotor 37, to allow rotation of the movable contact arm 32 with respect to the rotor 37. A molded peg 114 extends from the face 19 of the rotor.37. With reference to Figures 2 and 4, the rotor 37 is assembled within the first half-piece 14 of the cartridge, electrically insulating by placing the pin 114 within the slot 58. The pin 114 allows the travel of the rotor 37 within the slot 58. In case the pin 114 is not properly fitted within the groove 58 with the rotor assembly 37 inside the first half piece 14 of the electrically insulating cartridge, then the second half piece 60 of the cartridge, electrically insulating it will not coincide correctly with the first half part 14 of the cartridge, electrically insulating. In this way, the correct termination of the box will not be achieved. With reference to Figure 5, the arc blow box unit 22 for a circuit breaker is shown. The arc blow box unit 22 includes a plurality of plates 68, a first side member 70 and a second side member 72.

Typically, the plates 68 are metallic to thereby induce magnetism, which promotes the withdrawal of the arc generated by the short-circuit disconnection in the circuit breaker. Each plate 68 has a protrusion 74 extended from each side thereof. Each plate 68 also includes a notch 78 with radius formed on one side thereof. The notch with radius 78 provides space for the contact arm 32 when the arc blow box unit 22 is mounted within the half pieces 14, 60 of the cartridge, electrically insulating (Figures 2 and 3). With reference to Figures 5 and 6, the first and second side members 70, 72 have a plurality of grooves 76 formed therethrough. The protuberances 74 of the plates 68 are inserted respectively into a corresponding one of the grooves 76 formed in the first and second side members 70, 72. The plates 68 are arranged in this manner between the first and second side members 70, 72 and are arranged in a separate relationship, stacked together. The second side member 72 is identical to the first side member 70. The first and second members 70, 72 are assembled to be oriented opposite each other. . The first side member 70 has a tab 80 located in the center at an opposite end of the groove 78 with radius. A tongue 80 is similarly located along the second lateral member 72. A second arc blowing box unit 20 comprises a plurality of plates 68 and the third and fourth side members 82, 84. The third and fourth lateral members 82, 84 are identical to the first and second lateral members 70, 72. The third and fourth side members 82, 84 are assembled to be oriented opposite each other. The third side member 82 has a tongue 80 located centrally at an end opposite the notch 78 with radius of the plate 68. A tongue 80 is similarly located along the fourth side member 84. With reference to Figures 2 and 5, the first arc blowing box unit 22 is correctly positioned within the first half-piece 14 of the electrically insulating cartridge, by placing the tongue 80 of the first side member 70 within the first recess 56 of the first half piece 14 of the electrically insulating cartridge. Similarly, the second arc blowing box unit 20 is correctly positioned within the first half piece 14 of the electrically insulating cartridge, by placing the tongue 80 of the third side member 82, within the second recess 54 of the first half piece 14 of the electrically insulating cartridge. In case the cartridge unit does not include the tabs 80 and the recesses 56, 54 to correctly position the arc blowing box units 20, 22, for example, then the notches 78 in the plates 68 may be incorrectly positioned for facing opposite the first and second mobile contacts 30, 36 and the first and second contacts 28, 34 fixed. In the event that this occurs, the arm 32 of the moving contact will not be allowed to rotate when the circuit breaker is disconnected due to a short circuit event. Also, the arc blowing box unit 22 can be placed downward with respect to the first piece 14 of the electrically insulating cartridge. When this occurs, then there may not be sufficient air space between the plate 68, which is the N near the first mobile contact 30 and the lateral contact belt 16 in line. The loss of a conductive plate in the arc blowing box unit 22 may result in an insufficient amount of electromagnetic force to extinguish the arc. In this way, the tongues 80 ensure the correct positioning of the arc blowing box units 22, 20 within the recesses 56, 54. Referring now to Figures 2, 3, 4 and 5, after the first and the second 22 units, 20 of the arc blow box have been properly positioned within the first half piece 14 of the electrically insulating cartridge, the second half piece 60 of the electrically insulating cartridge is placed on the first half piece 14 of the electrically insulating cartridge to form a complete box . As a result, the tongue 80 of the second side member 72 will be inserted into the third recess 64 of the second half piece 60 of the electrically insulating cartridge. The tongue 80 of the fourth side member 84 will be inserted in the same way, within the fourth recess 66 of the second half piece 60 of the electrically insulating cartridge. In this way, the first and second arc blowing box units 22, 20 will be correctly positioned within the first and second half pieces 14, 60 of the electrically insulating cartridge. Thus, the correct operation of the rotating contact arm unit is achieved. The first, second, third and fourth side members 70, 72, 82, 84 have been described before within the present with tabs 80 located at the center. The advantage of this arrangement of the tabs 80 together with the respective ends of the side members 70, 72, 82, 84 are the cost savings attributed to the formation of a single mold pattern that can be used for all the members 70, 72, 82, 84 for the first and second arc blowing box units 22, 20. Since the first and second arc blow box units 22, 20 are assembled before placement within the first half piece 14 of the electrically insulating cartridge, the placement of the first and second box units 22, 20 Arc blowing can also be achieved by using tongues 80 only on the first and third side members 70, 82. In this alternative embodiment, the second and fourth side members 72, 84 will not have tabs 80. However, this will require the manufacture of two different side members in structure. Also, the tabs 80 in the first and third side members 70, 82 can be located generally offset opposite the central location along the edges of the respective side members. However, this will also require the manufacture of a third type of lateral member to accommodate the displaced tab arrangement. As described herein, a cartridge unit for rotary contact circuit breakers utilizing a first half piece of electrically insulating cartridge 14 and a second half piece 60 of the electrically insulating cartridge, which are arranged to coincide with each other to form a box. The half pieces 14, 60 of the electrically insulating cartridge include inadequate installation rejection characteristics for both the rotor 37 and the arc blow box units 22, 20. Therefore, the cartridge unit as described herein, prevents such disassembly and reassembly which can be time consuming and can increase the production cost of the circuit breaker.

While the invention has been described with reference to the preferred embodiment, those skilled in the art will understand that changes can be made and that equivalents can be replaced by elements thereof without departing from the scope of the invention. In addition, modifications can be made to adapt it to a particular situation or material with the teachings of the invention without departing from the essential scope thereof. Therefore, it is intended that the invention is not limited to the particular mode described as the best mode contemplated for carrying out this invention, but rather that the invention includes all modalities that fall within the scope of the invention. appended claims.

Claims (19)

1. A cartridge unit suitable for use in a circuit breaker, which comprises: a first half piece of the electrically insulating cartridge having an inner surface, the inner surface having a first recess formed therein; a second half piece of the electrically insulating cartridge having an inner surface and the second half piece of the electrically insulating cartridge being \ arranged to coincide with the first half piece of the electrically insulating cartridge; and a first arc blowing box unit arranged between the first and second half pieces of the electrically insulating cartridge, the first arc blowing box unit includes; a first lateral member; a second lateral member; a tongue extended from the first side member and through the first recess, to place the first side member on the first half piece of the electrically insulating cartridge; and a plurality of plates disposed from the first and second side members and arranged in a separate, stacked relationship.

2. The cartridge unit according to claim 1, wherein the first and second side members include a plurality of grooves formed therethrough and each of the plurality of plates, respectively includes a protrusion extended from each side thereof, the protuberances extend through the slots in the first and second side members.

3. The cartridge unit according to claim 1, wherein the first side member includes an upper end and a lower end and a mid point located along the first side member between the upper and lower ends and wherein the tongue is located at the midpoint of the first lateral member.

4. The cartridge unit according to claim 1, wherein the inner surface of the second half piece of the electrically insulating cartridge includes a third recess formed therein and also includes a tongue extended from the second side member and through the third recess for placing the second side member on the second half piece of the electrically insulating cartridge.

5. The cartridge unit according to claim 4, wherein the second side member includes an upper end and a lower end and a mid point located along the second side member, between the upper and lower ends and where the tongue is located at the midpoint of the second lateral member.

6. The cartridge unit according to claim 1, further including a second arc-blow box unit arranged between the first and second half-pieces of the electrically insulating cartridge, wherein the inner surface of the first half-piece of the cartridge is electrically insulator includes a second recess formed therein, the second arc-blow box unit includes: a third side member; a fourth side member; a tongue extended from the third side member and through the second recess to place the third side member in the first half piece of the electrically insulating cartridge; and a plurality of plates disposed between the third and fourth members and arranged in a separate, stacked relationship.

7. The cartridge unit according to claim 6, wherein the third and fourth side members include a plurality of grooves formed therein and each of the plurality of plates includes a protrusion extended from each side thereof, the protrusions being They extend through the grooves in the third and fourth side members.

8. The cartridge unit according to claim 6, wherein the third side member includes an upper end and a lower end, and a mid point located along the third side member between the upper and lower ends and where the tongue is located. located at the midpoint of the third lateral member.

9. The cartridge unit according to claim 6, wherein the inner surface of the second half piece of the electrically insulating cartridge includes a fourth recess formed therein and also includes a tongue extended from the fourth side member and through the fourth recess for placing the fourth side member on the second half piece of the electrically insulating cartridge.

10. The cartridge unit according to claim 9, wherein the fourth side member includes an upper end and a lower end and a mid point located along the fourth side member between the upper and lower ends and wherein the tongue is located at the midpoint of the fourth side member.

11. A circuit breaker unit comprising: a first half piece of the electrically insulating cartridge having an inner surface, the inner surface having a first recess and a second recess formed therein; a second half piece of the electrically insulating cartridge has an internal surface, the second half piece of the electrically insulating cartridge is arranged to coincide with the first half piece of the electrically insulating cartridge; a first arc blowing box unit arranged between the first and second half pieces of the electrically insulating cartridge, the first arc blowing box unit includes: a first side member; a second lateral member; a tongue extended from the first side member and through the first recess to place the first side member in the first half piece of the electrically insulating cartridge; and a plurality of plates disposed between the first and second side members and arranged in a separate, stacked relation; a second arc blowing box unit arranged between the first and second half pieces of the electrically insulating cartridge, the second arc blowing box unit includes: a third lateral member; a fourth side member; a tongue extended from the third side member and through the second recess to place the third side member in the first half piece of the electrically insulating cartridge; and a plurality of plates disposed between the third and fourth side members and arranged in a separate and stacked relationship; an in-line side contact strap arranged for connection to an electrical circuit, the in-line side contact strap includes a first fixed contact connected to the in-line side contact strap, the first arc-blow box unit near the On-line side contact strap to extinguish arcs that occur with an overcurrent condition; a lateral ac / g contact strap arranged for connection with the associated electrical equipment, the lateral load contact strap includes a second fixed contact connected with the lateral load belt, the second arc blow box unit near the side-loading contact strap to extinguish arcs that occur with an overcurrent condition; a rotor defining the first and second opposite sides thereof; and an intermediate mobile contact arm on the first and second sides, the movable contact arm defines a first movable contact at an arranged end opposite the first fixed contact and a second movable contact at an end opposite an end arranged near the second fixed contact , the rotor and the mobile contact arm are retained intermediate to the first and second half pieces of the electrically insulating cartridge;

12. The circuit breaker unit according to claim 11, wherein the first side member includes an upper end and a lower end, and a midpoint located along the first side member, between the upper and lower ends and where the tongue is located at the midpoint of the first lateral member, wherein the third lateral member includes an upper end and a lower end, and a midpoint located along the third lateral member, between the upper and lower ends and where the tongue is located at the midpoint of the third lateral member.

13. The circuit breaker unit according to claim 11, wherein the second side member includes an upper end and a lower end, and a mid point located along the second side member, between the upper and lower ends and where the tongue is located at the midpoint of the second side member, wherein the fourth side member includes an upper end and a lower end, and a midpoint located along the fourth side member, between the upper and lower ends and where the tongue is located at the midpoint of the fourth side member.

14. A rotational contact unit of the circuit breaker, comprising: a first half piece of the electrically insulative cartridge having an internal surface, the inner surface having a groove; a second half piece of the electrically insulating cartridge arranged to coincide with the first half piece of the electrically insulating cartridge; a rotor defining the first and second opposite sides thereof, the rotor includes a pin formed on the first side, the pin extends into the slot to allow the rotor to travel within the slot; an intermediate mobile contact arm on the first and second sides, the movable contact arm defines a first movable contact at a fixed end opposite an opposed first fixed contact and a second movable contact at the opposite end of an end arranged near the second contact fixed, the rotor and the movable contact arm are retained intermediate to the first and second half pieces of the electrically insulating cartridge; and a pivot pin extended from a central portion of the movable contact arm to a central portion of the rotor, to allow rotation of the movable contact arm with respect to the rotor.

15. A circuit breaker unit, which comprises: an in-line side contact strap arranged for connection to an electrical circuit, the in-line side contact strap includes a first fixed contact connected to the in-line side contact strap; a side load contact strap arranged for connection with the associated electrical equipment, the side contact strap includes a second fixed contact connected to the side load contact strap; and a rotary circuit unit of the circuit breaker disposed between the side-on-line and lateral-load straps, the rotary contact unit of the circuit breaker includes: a first half-piece of the electrically insulative cartridge having an internal surface, the inner surface has a groove; a second half piece of the electrically insulating cartridge arranged to coincide with the first half piece of the electrically insulating cartridge; a rotor defining first and second opposite sides thereof, the rotor includes a pin formed on the first side, the pin extends into the slot to allow the rotor to travel within the slot; an intermediate mobile contact arm on the first and second sides, the movable contact arm defines a first movable contact at a fixed end opposite the first fixed contact and a second movable contact at an end opposite an end arranged near the second fixed contact, the rotor and the movable contact arm are retained intermediate to the first and second half pieces of the electrically insulating cartridge; a pivot pin extended from a central portion of the movable contact arm toward the central portion of the rotor to allow rotation of the movable contact arm with respect to the rotor.

16. The circuit breaker unit according to claim 15, further comprising a first arc blow box unit arranged between the first and second half pieces, wherein the inner surface of the first half piece of the electrically insulating cartridge includes a first recess formed therein, the first arc blowing box unit includes: a first side member; a second lateral member; a tongue extended from the first side member and through the first recess to place the first side member in the first half piece of the electrically insulating current; and a plurality of plates disposed between the first and second side members and arranged in a separate, stacked relationship.

17. The switch unit according to claim 16, further comprising a second arc blow box unit arranged between the first and second half pieces of the electrically insulating cartridge, wherein the inner surface of the first half piece of the cartridge is electrically insulator includes a second recess formed therein, the second arc-blow box unit includes: a third side member; a fourth side member; a tongue extended from the third side member and through the second recess to place the third side member in the first half piece of the electrically insulating cartridge; and a plurality of plates disposed between the third and fourth member and arranged in a separate, applied relationship.

18. The circuit breaker according to claim 17, characterized in that the first side member includes an upper end and a lower end and a mid point located along the first side member, between the upper and lower ends and where the tongue is located at the midpoint of the first lateral member, wherein the third lateral member includes an upper end and a lower end and a midpoint located along the third lateral member, between the upper and lower ends and where the tongue is located at the midpoint of the third lateral member.

19. The circuit breaker unit according to claim 17, wherein the second side member includes an upper end and a lower end, and a midpoint located along the second side member, between the upper and lower ends and where the tongue is located at the midpoint of the second lateral member, wherein the fourth lateral member includes an upper end and a lower end and a midpoint located between the fourth lateral member between the upper and lower ends and where the tongue is located at the midpoint of the fourth side member.