US2386162A - Single throw hill and valley switch - Google Patents

Description

2,1945: R.HETHERINGTON 2,386,162

" SINGLE THROW HILL AND VALLEY SWITCH Filed Oct. i7, 194; 27Sheets-Sheet 1 /V/VI/ I 1945- R. HETHERINGTON 2,386,162 Y SINGLE THROW HILL AND VALLEY SWITCH Filed Oct. '1? 1942. 2' Sheets-Sheet z Patented Oct. 2, 1945 UNITED STATES PATENT Y OFFICE SINGLE THROW HILL AND VALLEY SWITCH Robert Hetherington, Sharon Hill, Pa., assignor to Robert Hetherington & Son, 1310., Wilmington, Del., a corporation ofDelaware Application October 17, 1942, Serial No. 462,349'

2 Claims. (01200-47) My invention relates toplunger switches whose movable contacts are carried by a shuttle.

A purpose of the invention is to reduce the diameter of a wedge-throw shuttletype plunger switch. I

A further purpose is to press the taper of the switch against the operating balls of a wedge type shuttle switch thereby moving the balls out-' wardly against the tension of a surrounding spiral spring directly engaging the balls.

A further purpose is to reduce the length of a Wedge plunger extension by placing the retracting spring for the plunger largely within the plunger and using the plunger extension about the spring to limit movement in one direction.

A further purpose is to fit a closing plate uniformly and firmly against divided contacts with which it engages by a three point pressure contact.

A further purpose is to apply lost motion spring overthrow to a wedge-operated contact having independentspring retraction.-

Further purposes will appear in the specification and in the claims.

Figure 1 is a side elevation largely in longitudinal section upon line [-4 in Figure 2, showing a single pole, single throw switch embodying the invention.

Figure 2 is a left end elevation of the structure of Figure 1 from the position of line 2-2 in Figure 1.

Figure 3 is a right end elevation from the position of line 3-3 in Figure 1.

Figure 4 is a section of Figure 1 taken upon the line 44. 1

Figure 5 is a view corresponding to Figure 1 but showing a single pole double throw form.

Figure 6 is a section of Figure 5 taken upon line 6-6.

Figure 7 is a view corresponding to Figures 1 and 5 except that it shows a two circuit switch.

Figure 8 is a section of Figure '7 taken upon the line 88. i

In the figures similar numerals parts.

Figure 1 shows a normally closed switch. in Figure 5 thecontactsare closed at each end of the stroke to provide different directions of current flow, one binding post of one pair of contacts being permanently connected with one binding post of the other pair of contacts.

In Figure 8 separate circuits are closed at the two ends of the stroke.

I will describe first the construction shown in Figures 1-4. The description applies generally indicate like to the other figures which, however, differ in detailfrom it. p V

The'outer shell II is of metal, initially open at one end, the left end in the figures, which as the switch is mounted becom'esthe rear end, to form a bore l2 within which is placed rearwardly cupped insulation [3. The recess provided by the inside of the cup is almost closed at the front end, in the'figure right hand end, by an inwardly directed inner insulating flange l4 about an opening l5. 7 The bore of the metal shell or casing is inwardly contracted at ,thefront end to form an annular front wall l6 surrounding the rearwardly facing openend I] of a chamber or space [8. The forwardjend of the chamber carries an inwardly directed guiding flange [9 about an opening 20.

The front'end of the casing surrounding chamber i8, is externally reduced'to fit within any suitable switchboard or othersupport upon which the switch is-to bemounted and is threaded at 2 I so that it may be fastened to the board in the usual way by nuts 22 and washer 23.

Within the chamber l8 slides hollow push button 24- containing an overtravel spring 25. This spring presses at one end 26 against the inner front end of the'button and at the other end against a collar 21 carried by the switch plunger 28.

At the front end, the plunger section 29 is of insulating material. The. section is rigid with the collar 2-! and with the spring-surrounded pin The push button is outwardly flanged at 3| to engage with the wall [9 and initially is provided with an axial tubular extension 32. The extension is sp'un inwardly into a flange 32 after the plunger end including collar 21 has been placed inposition within the interior of the buttonu v J Thespring'can bediagonal to provide any normal' expansion desired and is compressed within the interior of thebutton asthe collar is inserted, and since the diameter, stiffness and other characteristicsof the spring can be predetermined, the pressure required to further compress the spring may also be predetermined. The unit of button, spring and contained collar will move as a unit to the left in Figure 1 asthe button is pressed inwardly (to left) until the pressure upon the plunger exceeds the preliminary preloading resistarice of the spring. Subsequent movement of thebutton' to the left will progressively compress spring '25.

i The frontof the plunger isiinsulated from the cones, located on opposite sides of a dividing line or crest 43 are placed with their bases together and converge away from the crest. These are usedto effect switch movement and are spaced from the flange 31 in front and from the sleeve 4| in the rear (part of the retraction section) by rests or dwells 42 and 43, each of smaller diameter than the cones. The sleeve 4| is bored at 44 at the rear of the plunger to receive a retraction sprin 45 which presses at its rear end against the bottom of a recess 46 in insulating disc 41, and at its front end against the bottom of the bore. The lateral walls of the-recess and of the bore of the sleeve support the spring laterally.

The full-stroke wedge operating section includes the conical wedges described, oppositely facing and having their bases back to back. The double-taper or double-wedge plunger thus provided is'moved to the left by pressing the button shown and is free to move until the end 48 of the collar or sleeve 4| engages the bottom of the recess in the rear insulation. Movement of the button can still continue but from that point on is accompanied by compression of spring 25 and is for the purpose of accommodation of overtravel.

The operating part of the plunger, about the conical wedges, is surrounded by a shuttle contact maker 49 whose face or faces engage with fixed contacts to close circuits and whose interior section is radially bored at 50 to accommodate balls inwardly spring pressed to engage the cones. The balls push inwardly against the cones. The shuttle 49 is circumferentially grooved at 5-2-to a depth below the lowest radial depth 53' to which the outer surfaces of the balls can move so that a spiral ring (tensioned) spring 54 will constantly engage the balls 5|. The spring constantly will press the balls inwardly, with consequent stretch of the spring circumferentially when the balls are forced radially outwardly, by movement of the wedge, from the position seen in Figure l to or toward a position in which the crown or crest of the double wedge is directly under the centers of the balls.

The'switch shuttle 49 in Figure 1 carries a silver face-contact disc- 55 by which contact is closed at the left end of the stroke-here the normal position of the parts-with individual contact plates 56 and 51 connected one each with the two binding posts 58 and 59. The connection through the cap between the binding posts and these plates 56 and 51 is preferably made while these plates are still in single annular disc form, after which they are separated by cutting away the metal between edge 60 and edge 6|.

In operation: starting with the parts in the position in Figure 1 in which the silver disc 55 is in contact with both of the semi-circular disc plates 56 and 51,- the button .24 is pressed to the left and movesgias a unit with the connecting insulation and the wedges carrying the plunger to the leftwithoutcompressionof thespring 25 but with continuing compression of the retraction sprin 45.

The motion of the plunger to the left in Figure 1 continues while the double wedge passes under the balls, pushing the balls to the left against W radially outer limit of ball movement is reached v as the crest of the double wedge (cam) passes under the balls. During the beginning of the wedge movement of the double cam, the zone of the cones changes and the wedge surfaces acting against the balls progressively increase in diameter, until the crest of the double wedge reaches the center line of the balls. Before the crest passes the centers of the balls the shuttle spool is pressed to the left in Figure 1, tightening pressure of the radial face of thespool (i. e.,-the pressure of its silver contact disc) against the face surfaces of the two lunar plates.

It will be noted that the pressure exertedby the balls tending to seat the silver contact disc more tightly against the lunar plates is a three-point pressure facilitating accommodation of the disc surface to the plane of the faces of the lunar plates or to the effective plane of these surfaces if they be not exactly within a plane. It will also be clear that when the switch shifts in either direction the force pressing and holding the switch home at either end of its stroke is a three point pressure with the same advantages as above.

Just as soon as the crest of the plunger double wedge passes operatively beyond the centers of the balls the retractive pressure of the circumferentially spiralled ring spring pressing the balls inwardly snaps the ball-supporting carrier or shuttle spool to the right, opening the circuit contacts separately between each of the plates 56 and 51 and the annular disc and throwing the shuttle back to the right. 7

Continued pressure of the operating force against the end of the button can still cause movement of the button to the left in Figure l but it can cause no further movement of the shuttle (as distinguished from movement due to the Wedges which it carries) to open position at the right.

Movement of the plunger to the left need not go farther than to throw the crest of the double cone wedge or cam beyond the center line of the balls as they lie (slightly beyond the center line of the bores in which they lie) so as reliably to bring the right hand cam or cone to bear upon the balls and shift to the right the switch carrier, shuttle 49.

When a position of the plunger operatively beyond engagement of the crest of the double wedge or cone with the center line of the balls has been reached, movement of the plunger to the left need go no farther. It may be stopped by having the end 48 of sleeve 4| engage the bottom in the recess or hollow 46.

Continued pressure against the button exceeding the compressive pressure to which, as a minimum', spring 25 has been set causes overtravel but the spring 25 meantime is compressed to a higher pressure than the minimum at which the spring was set. i

When pressure upon the push button is released the first thing that takes place- -if there has been any overtravelis that spring 25 expands to its pre-set position. No movement of the plunger takes place during this expansion of spring 25. Next, retraction spring 45 expands, shifting the plunger to the right in Figure 1. As the shuttle is in its right hand position this causes no movement of the shuttle until the crest of the double cone passes beyond the center lines of the balls, subjecting the balls, and hence the shuttle, to the wedge pressure of thecone surface lying at the left in Figvure 1 and bringing the parts back to their initial position in Figure 1 and closing the switch.

The structure in Figure 5 is intended to correspond with that in Figures 1-4 at the. left hand end of the construction and so far as affects the normally closed position of the switch parts seen in Figure 1. However, in Figure 5, a single pole double throw switch is shown, in which a second fixed pair of plates 56', 51' is 7 provided within the path of travel of the shuttle but at the right hand end of the shuttle. The second pair is coaxial with the first pair. Plates 56, 51 are secured to insulation 62 held within the right hand (bottom) of the bore of the casing. An outside cross connection 63 shown in Figure 5 cross-connects one plate of each pair with a plate of the other pair.

In Figures 7 and 8 a construction similar to that of Figure 5 is shown but the switch is normally open and there are no fixed contacts to be closed by the shuttle in its switch throwing plunger movement (to the left in Figure 7).

As compared with Figure 5, Figure 1 omits the fixed contacts found at the right in Figure -5, engaging those only that are found at the left in Figure 5 while Figure 7 omits the contacts found at the left in Figure 5 and shows those only found at the right in Figure 5.

In Figures 7 and 8 binding posts not shown are connected with the plates 56' and 51' which constitute the fixed contacts of these figures. They are preferably constructed in the same way as the fixed contacts shown in Figure 6.

Having thus described my invention what I claim as new and desire to secure by Letters Patent is: 7

1. In a plunger operated shuttle switch, an axially movable plunger having an operating member in the form of a doulbe cone, the cone parts being placed base to base, a shuttle about the cone, inwardly movable balls in the shuttle engaging the cone parts and snapped by the cone parts with plunger movement in directions opposite to those of the shuttle, meanscommon to all of the balls engaging the balls and pressing them inwardly, a retraction spring withina circumferential recess in the plunger, a stop at the rear end of the plunger engaging a fixed part of the switch to limit plunger movement and operating means for the plunger.

2. In a plunger operated shuttle switch, a

plunger having an operating member in the form of a double cone placed base to base, a shuttle about the cone, inwardly spring-pressed balls in the shuttle engaging the cones and snapped by the cones with plunger movement in opposite ROBERT HETHERINGTON.

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