Tn U.S. Pat. No 3,612,793 issued on Oct. 12, 1971, to John O. Roeser and entitled "Electrical Switch Components And Switches Formed Thereby," there is shown and described a unitary combination switchblade and contact means For compact switch mechanisms. As can be seen from FIGS. 8, 9 and 10 of the '793 patent, the combination switchblade and contact means 16 comprises a pair of identical members 109a (109b) each being formed of a first end portion 110 a mid-portion 116 and a curvilinear second end portion 118. The first end portion 110 consists of a pair of spaced apart legs 112 and 114. The legs are spaced apart by a dimension D so as to receive therebetween a tension spring 120, as illustrated in FIG. 5. A combination strut and attachment means 124 is shear formed in the curvilinear second end portion 118 and includes a reverse curve portion 131 for mating with the end of the tension spring 120 (FIG. 5).
The curvilinear second end portion 118 further includes an upper contact portion 128 and a lower contact portion 130 which is separated from the upper contact portion 128 by means of the reverse curve portion 131. The legs 112 and 114 are provided with sharpened edges 132 for pivoting within opposed V-shaped notch portions 106 formed within an elongated metal member 74 of the actuating means 114. The lower contact portion 130 is located within the same plane as the first portion 110 and the mid-portion 116 However, the upper contact portion 128 is off-set from that same plane. The lower and 15 upper contact portions 128 and 130 define movable contact members which are adapted to be snapped between opposed fixed contact portions upon upper terminal members 134 and lower terminal members 136, as illustrated in FIG. 5.
The upper portions of the upper terminal members 134 are formed with an off-set transverse portion 116 having a depending upper fixed contact 148 (FIGS. 14 and 15). The upper fixed contacts 148 serve to make electrical contact engagement with the upper contact portions 128 of the movable contact members. The lower terminal members 136 are provided with portions 156 which serve as lower fixed contacts for electrical contact engagement with lower contact portions 130 of the movable contact members.
The combination switchblade and contact means 16 is assembled with other components so as to form a compact precision, snap-action push-button switch 10 and is illustrated in FIGS. 2, 5 and 6. In operation, when the button 72 of the actuator means 14 is depressed so as to move downwardly, this causes the elongated metal member 74 to also more downwardly against the bias of the return springs 76 and 78. Initially, the combination 15 switchblade and contact means is restrained by means of the lower fixed contact portions 156 so that the lower contact portions 130 of the movable contact members remain in contact therewith.
This contact continues until the pivot points 106 pass the center line of the tension spring 120. At that time, the movable contact members will snap overcenter and the upper contact portions 130 thereof will become engaged with the upper fixed contacts 148. This engagement continues until such time when the pressure upon the top of the button 72 is released, thereby causing the return springs 76 and 78 to return the metal member 74 and button 72 to their rest positions shown in FIGS. 1 and 2. As the metal member 74 returns past the center line of the tension spring 120, the movable contact members will snap overcenter again in the reverse direction.
The present invention represents an improvement over the combination switchblade and contact means described above in connection with the '793 patent. The upper contact portion 128 and the lower contact portion 130 upon the second end portion 118 of the switchblade and contact means 16 in the aforenoted patent experience a high degree of stress during the switching operations which tends to shorten the service lives of such components. It would therefore be desirable to provide a novel and improved switch butterfly assembly for use in precision snap action switches which has a unique configuration so as to reduce the stresses upon the movable contact portions, thereby prolonging the service lives thereof.