US2941051A - Switch mechanism - Google Patents

Description

June 14, 1960 D.-\N. LAVIANA SWITCH MECHANISM Filed July 30, 1958 INVENTOR. 00/0110 ll MV/IM/I BY I l A H/J ATM/1WD United States Patent 2,941,051 swrrcn MECHANISM Donald W. Laviana, Pittsford, N.Y., asslgnor to General Motors Corporation, Detroit, Micln, a corporation of Delaware Filed July 30,1958, Set. No. 151,910

1 Claims. c1. 200-38 This invention relates to switch and control mechanisms such as may be used in program timers.

In the design of program switches, some means is usually employed to effect a fast action of the make and break of the contacts to avoid excessive contact deterioration. A popular means of accomplishing such fast act-ion is to advance the actuating earns in quick steps through an escapement. Although this jump type switch works satisfactorily when properly adjusted, considerable difficulty is experienced in their manufacture due to a multiplicity of tolerances which affects the relation of the switches and their operating cams.

It is an object of this invention to provide a switch actuating arrangement in which there is eliminated the necessity of individual switch adjustment andwhich allows larger manufacturing tolerances without comprising accuracy of timing. I

It is another object of this invention to provide fast making and breaking of contact mechanisms when a slow, constant speed cam drive is provided.

These and other objects are attained in the form shown in the drawings in whicha constantly rotating slow speed cam is provided with abrupt peripheral drops to suddenly move a spring pressed cam follower. The follower is provided with a saw-tooth cam surface which either cooperates with a guideway or with a V-shaped hump on a spring contact member to move in either form a spring contact member between normally stationary contacts.

Further objects and advantages of the present invention will be apparent from the following description, reference being had to the accompanying drawings wherein a preferred embodiment of the present invention is clearly shown.

In the drawings:

Figure 1 is a perspective fragmentary view of a program timer embodying one form of my improved switch mechanism; and

'Figure 2 is a fragmentary sectional view of a program timer illustrating a modified form of my improved switch mechanism.

Referring now' to the drawings and more particularly to Fig. 1, there is shown a timer motor 20 which either constantly or intermittently rotates the drive pinion 2. The drive pinion 2 meshes with .and rotates a gear wheel 1 rotatably mounted on the'c am shaft 3. A wound spring clutch 4 connects the gear 1 to the shaft 3 when the gear 1 is rotated in the clockwise direction and disconnects the gear 1 from the shaft 3 when the shaft 3 is turned in the clockwise direction. A spring detent engages the teeth of the gear wheel 1 to prevent counterclockwise rotation thereof. Fixed to the shaft 3 is a cam 5 having a section 21 of maximum radius and successively reduced sections 22, 24 and 26 of successively reduced radius, with sharp drops between the sections. Between the sections 26 and '21 there is provided a more gradual incline 28.

A cam follower or switch operator 7 is normally held in engagement with the periphery of the cam 5 by a of the housing of the timer.

cantilever arranged looped wire spring 8 extending through a notch in the top of the follower 7 to urge it downwardly. The left edge of the follower 7 is provided with'a sawtooth cam surface 30. The cam follower 7 is slidably mounted in a guide means 9 formed as a part The guide means 9 is provided with a groove 32 slidably receiving the follower 7 and having a sawtooth cam surface 34 in the bottom of the groove 32 which is complementary to the cam surface 30 upon the follower 7. A spring switch blade 36 has a spring bias against the adjacent ventical edge of the follower 7 to hold the cam surfaces 34 and 30 in engagement. The spring switch blade 36 is anchored to a housing portion 38. The opposite end of the spring switch blade 36 carries a double contact 40 adapted to make contact at opposite limits of its movement with the the blade 36 stationary contacts 42 and 44. The height of the fiat top saw teeth cam surfaces and 34 is just suflicient to pro vide movement of the double contacts between the contacts 42 and 44.

When the tops of the teeth of the surfaces 30 and 34 are in contact, the cam follower 7 and the blade 36 are cammed to the right sufliciently to cause engagement of the contacts 40 and 44. When the saw teeth of the surfaces 30 and 34 are exactly in mesh, the spring effect of will carry the follower 7 and the contact 40 to the left extremity of their movement to make con-. tact with the contact 42. When the saw teeth are in contact intermediate the top and the bottom, the blade vent current flow to either contact.

36 will be held between the contacts 42 and 44 to pre The radii of the different segments 21, 22, 24 and 26 may be so chosen to hold the teeth either with the tops in engagement or nested, or at intermediate points to provide the switch positions desired. The ramp 28 returns the follower 7 to its upper position. The knob 46 fastened to the right end of the shaft 3 may be used to manually turn the shaft 3 and the cam Sin the clockwise direction.

In Figure 2, a cam is fixed to a shaft 53 and similarly includes sections 57, 59, 61 and 63 of progressively reduced radii. The junctions of the sections are provided by sharp drops. Between the sections 63 and 57 there is provided a gradual lifting ramp 65. This cam 55 and the shaft 53 may be similar to the corresponding mechanism in Figure 1 and may be similarly provided with a drive mechanism and knob.

A cam follower 67 is provided with a foot 69 held in engagement with the periphery of the cam 55 by a tension coil spring 71. The follower 67 is somewhat T.- shaped and is provided with a sawtoothed cam surface 1 73 on its lower edge. The upper edge of the follower 67 is received within the notches 75 in the guide members 77.

Beneath the cam follower 67 is a spring blade 79 provided with an anchorage 81 at one end and a double contact 83 at the opposite end. The double contact 83 operates between the upper and lower stationary switch contact members 85 and 87. At an intermediate point of the switch blade 79 there is provided an inverted V shaped hump 89' substantially complementary to the notches between the saw teeth of the cam surface 73. When the hump 89 rests on one of the tips of the saw teeth, as shown in Figure 2, the switch blade 79 will be pushed downwardly to move the contact 83 into engagement with the contact 87. When the cam moves the follower 67 so that the hump 89 is in any of the notches between the saw teeth of the cam surfaces 73, the spring force of the blade 79 will carry the contact 83 into engagement with the upper stationary contact 85. When the cam 55 moves the follower 67 so that the hump 89 is at an intermediate point upon any of the teeth of the ens on cam surface 73, the contact '83 will be held at an intermediate point out of "contact with both'the upper and lower contacts 85 and 87.

As described in Figure l, the radii .ofthe cam 55-ma y be chosen so as to-movethe cam'fo1lower 67 to present cither'ahi'gh, low. 'or intermediate surface of the cam surface :7 3 in engagement withz'the hump'89 appropriately hold "the :switch blade in either lower, upper or .intermediateipositi'ons :as desired.

While the embodiment of the present invention ashorein disclosed constitutes a preferred form, it is to be understood that other forms might be adopted.

'What is claimed is as follows;

1. Aswitch mechanism including an actuating cam, a follower contacting and moved by said cam in .a general direction, guide "means for guiding said .follower in said general 'directio'nin 'ac'cordanc'eiwith themovement provided by "said cam, said follower being provided "with a 'cam'surface extending .generally parallel to said general "directions but having 'at least three successive distinct deviations'laterally of said general direction, and aswitch means operated'in accordance'with each of the deviations of'the cam surface of said follower'relettiVetofthe movement of said follower.

2. A switch mechanism 'including'an actuating camhav- 'ing a cam surface with at least three different distinct actuating sections "at different progressively decreasing distances from a base line, a follower contacting and moved in at least three distinctprogressive "movements "by 'said'cam and cam surface according to the contourof said surface, guide means for guiding "said follower in a general "direction in accordance withthe"movement provided by said 'cam, said"follower'also having'a fcam sur- "face extending at angles'to said'general direction topromeans in an intermediate "position or positions on either side DfSald intermediate: position.

.5. A switch mechanism.:including -.an actuating oam having a cam surface with at least three different distinct actuating sections, a follower contacting and moved by said cam and cam surface to'three corresponding different distances,'=gguide means for guiding said follower in a general direction in accordance with the movement provided by said cam, said follower having a cam surface with at least three deviations extending alternatelyv "at "angles 'tosaid general direction, and a switch'means havinga follower projection in contact with-the said follower cam surface operable to three different positions in response to them'ovem'ent of said follower.

A switch mechanism including an actuating cam having a -cam surface with *a'tleast three different distinct actuating sections, a follower contacting and moved-by s'aidcam' in 'at least three distinct movements in a general direction, said follower-having a cam surface provided 'with alternating deviations relative to said general direction, a guide means having a complementary cam surface in contact at one point with said "cam surface ofsaid follower, 'andsdoubl'e throw switch means alter 'n'ate'd a plurality of times lateral-lyof said general "diIE/b';

tion by thedistinct movements of 'said' follower relative to saidguide means.

7. A switch mechanism including an actuating cam, a follower contacting and 'moved by said cam in a general direction,- saidfollower having a cam surface provided with at least three distinctly separate deviations 3'. A switch mechanism including an actuating means,

a follower contacting and moved by saidactua'tingmeans, guiding means for guiding said follower 'in a general direction in accordance withthe movement provided by'said cam," said follower having a sawtoothed type of cam surface having at le'asttwo teeth extending generally'parallel to said general direction, a'three position switch means operated in accordance with deviations of the teeth of said sawtoothed cam surfacerelative to said "general direction, said actuating-means having means for holding said sawtooth cam surface "in three distinctly different positions relative to said switch means for holding said switch means in three different positions.

4. A switch mechanism including an actuating means,

a follower'contacting and moved by said actuatingm'eans,

' relative to said general direction, guide means having a complementary cam surface in contact at one point'with said cam surface of said follower, a laterally movable switch blade operably connected to said follower'for distinct movements laterally of said general direction corresponding to' said distinctly separate deviations, and spaced relatively stationary contacts laterally-located on opposite sides of said-switch blade and engaged by said switch blade at 'thecxtremityiof its movements.

References Cited in the'file of this patent UNITED STATES PATENTS 1,626,659 Austin et a1. May 3, 1927 1 ,842,371 Harrison Ian. 19, 1932 2,018,958 Jones et a1. Oct. 29, 1935 2,128,427 Means Aug. 30, 1938 2,231,218 "Palmer Feb. 11, 1941 2,814,683 Wharton Nov. '26, 1957 FOREIGN PATENTS I 487,658 Great Britain June 23, 1938 827,608 Germany Jan; "10, 1952 "929,910 Germany 'July 7, 1 955

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