US3151490A

US3151490A - Ratchet relays

Info

Publication number: US3151490A
Application number: US175533A
Authority: US
Inventors: Kessler Seymour
Original assignee: Zenith Radio Corp
Current assignee: Zenith Electronics LLC
Priority date: 1962-02-26
Filing date: 1962-02-26
Publication date: 1964-10-06
Anticipated expiration: 1981-10-06

Description

Oct. 6, 1964 s. KEssLER RATCHET RELAYs Filed Feb. 2s, 1962 Seymour I c/Z Hy. 4

United States Patent O This invention is directed generally to ratchet relays, and more particularly, to a lngh sensitivity ratchet relay suitable for use in transistorized circuits.

Ratchet type relays, of course, are well known in the art and many designs have been evolved for different applications. in most, the ratchet part of the relay has assumed the rather classical form of a toothed ratchet wheel, a reciprocating pawl which engages the teeth of the wheel, and an additional pawl for preventing backward motion. ri`he reciprocating pawl usually includes a resilient ratchet device for engaging the teeth and some type of reciprocating lever. ln operation, the ratchet device is moved in one direction, corresponding to the backward motion of the toothed wheel which the pawl prevents, and then in the other direction Where the ratchet device engages a tooth of the wheel to rotate the wheel one step in a forward direction. This classical form of a ratchet is fully illustrated in almost any postwar issue of Websters Collegiate Dictionary.

lt is apparent that the ratchet must be flexible since during its backward motion it must ride up over a ratchet tooth. in the past, this has usually been achieved by means of a flexible leaf spring biased against a pivoted member. With the advent of transistorized actuating circuits, which have relatively low power output capacity compared to vacuum tube circuits, the classical ratchet device has been found to require an excessive amount of energy to operate it; i.e., an amount of er1- ergy above the rated capacity of most transistors in general use today.

it is, therefore, a primary objective of this invention to provide an improved ratchet relay.

lt is a specific object of this invention to provide a ratchet relay having a high sensitivity.

lt is a further object of this invention to provide a ratchet relay easily operated "oy transistoriled actuating sources.

lt is still another object of this invention to provide a high sensitivity ratchet relay of simple and inexpensive construction.

ln accordance with the invention, there is provided a high sensitivity ratchet relay comprising a supporting frame having a shaft journalled in it. A ratchet wheel is mounted for rotation with the shdt and in addition, a ratchet bracket is pivoted on the shaft and has t-.ro legs on opposite sides of the ratchet wheel, each of the legs having a guide channel of predetermined width extending radially outwardly from the shaft. A ratchet spring is retained by the bracket, the spring having a main portion of a thickness corresponding to the predetermined width of the guide channels extending through the guide channels in a direction substantially parallel to the shaft, captivated against relative movement perpendicular to the radial direction by the guide channels but free to move within the channels in the radial direction, and biased into engagement with the ratchet wheel. Means are provided for rotating the ratchet bracket and the ratchet spring to advance the ratchet Wheel and rotate the shaft.

The features or the present invention which are believed to be novel are set forth with particularly in the appended claims. The invention, together with further objects and advantages thereof, may best be understood by reference to the following description taken in connection with the accompanying drawing, in the several ligures of which like reference numerals identify like elements, and in which:

FIGURE l is an elevational front View of a ratchet relay embodying the invention;

FGURE 2 is an elevational rear view partially in section and partially cut away of the relay of FIGURE l;

FEGURE 3 is a partial sectional View taken along line 3-3 of FlGURE l; and

FEGURE 4 is a sectional view, partially cut away, taken along line 4-4 of FIGURE 3 but showing a portion of the mechanism in a different operating condition.

Referring now to FIGURES l and 2, an actuating coil lil is mounted on a supporting frame ll. More specifically, the coil is supported by an iron core consisting of pole pieces l2 and 13 as best shown in FlGURE 2. Each pole piece is constructed of two sandwiched iron plates, and the core is fastened by a screw 14 to a tab lla bent out from frame il. An armature 15 of rectangular outer shape and composed of two sandwiched iron plates having a central rectangular aperture circumscribes the exterior of coil lll. it is resiliently pivoted on the bottom portion of pole piece l2 (not shown) by a leaf spring lo. Energization of coil lil produces a flux path starting through pole pieces l2 and 13 extending through the bottom portion of armature l5 up through the legs of the armature and thence across the air gap between armature l5 and pole piece 13 above coil Armature l5 is attracted toward pole piece l pivoting in a counterclockwise direction as shown in FlG- URE 2 to actuate the relay in a manner to be described below.

The final result of the actuation of armature 15 is to rotate a conductive wiper arm i7, as shown in FlG- URE l, in a stepped type of motion into successive contact with a conductive contact surface 18. Conductive surface 13 may be formed of silver paint printed on an insulating board l? which is fastened to frame ll by fasteners The stepped motion of wiper arm i7 causes it to engage contact surface i8 every other rotational step, alternately making and breaking electrical contact.

A typical example of the use of such a switching device is in a remotely controlled television receiver where it is desired to remotely mute and unmute the audio of a television receiver. ln such a case, switch il?, 13 may be inserted in series with a lead to the loudspeaker of the television receiver.

The above portion of the relay which has been described is entirely standard in the art and may be modified as desired.

The invention is specilicaliy directed to a novel mechanism for coupling armature l5 to wiper arm l?, which mechanism includes ashaft 22 afxed to wiper arm 5.7 by a screw 2,3. Referring now to

FGURES

3 and 4, shaft 22 is journalled in frame 11 by a bearing bracket 24 which is aiixed to the frame by fasteners 20 and is also journalled in insulating board 19. A ratchet bracket 25 is pivoted on shaft 22 and has a bight portion 26 and two

legs

27 and 25 through which shaft 22 extends. A ratchet wheel 5l) is fixed to, and thus mounted for rotation with, shaft 22 between legs 27 and 2S. Legs 27, 21S are provided with respective guide channels or

slots

33, 34 which extend in a direction radially away from shaft 22 as best shown in FGURE 4.

A pawl or leaf spring 29, as best shown in FIGURE 2, is mounted on a tab 3l extending from frame 11 and engages the teeth of wheel 3@ to prevent back vard motion in the counterclockwise direction.

The ratchet mechanism of the relay includes a Wire ratchet spring 35 which is retained in

slots

33 and 34 in bracket 29. The ratchet spring includes a resilient multiple loop portion 36 and a main or straight portion 37 Yof loop 36 to ride over the teeth of atenas@ which extends through and is retained in

guide slots

33 and 34. Portion 37, as retained in the slots, extends in a direction substantially parallel to shaft 22 as best shown'in FGURE 4. Moreover,

guide slots

33 and 34 Vvated by a second bent end portion 4% which curves around the toprof slot 3.3. End portions .39 and 4t? are not anchored but serve to retain spring 35 in place by virtue of the resilience of loop portion 35 which biases the two end sections outwardly. Multiple loop portion 36 of spring 35 also serves to bias straight portion 37 into engag/ement with ratchet wheel 36. The fulcruming of loop portion 35 at the lower end of slot 34 allows lateral displacement of straight portion 37 against the biasing force wheel 3@ during the return stroke.

The amount of force needed to laterally displace portion 37 is considerably reduced because of two major factors. First, both ends of portion 37 are freely movable due to the iulcruming of loop portion 36 at the lower end of slot 34. Secondly, the retention of straight portion 37 by

guide slots

33 and 34 effectively prevents relative perpendicular movement thereby allowing ratchet spring 35 to have more exibility in the radial direction.

Ratchet bracket 25 and its associated ratchet spring 35 are coupled to armature in a manner which achieves the reciprocating motion necessary in ratchet relays of this type. This mechanism includes a drive rod 41 (FlG- VURES 2 and 4) journalled in a bearing 42 which is inserted in frame 11 and pole piece 13. Gne end or the rod is coupled to ratchet bracket by a pin d3, and the Yotther end is unilaterally coupled to armature 15 by means of a drive rod adjusting screw 44 which is mounted on an extensionVV 45 of armature 15. Ratchet bracket 25 is biased in a clockwise direction by a return spring 47 having one end coupled to ratchetrbracket 25 kand the i other to a bent out tab 4S of frame 11. Clockwise rotation of bracket 35 in response to the bias of spring i7 is limited by a collar 49 on drive rod 41 which abuts against bearing 42. Y Y

A conductive connection is made to wiper arm 17 as shown in FIGURE. 3 by means of a ground spring Sti. The spring is mounted on bearing bracket 2d to bear against a necked down portion of shaft 22; Spring 59 grounds shaft 22 to frame 11 which in turn is grounded to the chassis upon which it is usually placed.

Operation Repetitive energization of coil l@ successively steps wiper arm 17 into and out of contact with contact surface i8. As shown in FIGURE 1, wiper arm 17 rotates Vin a counterclockwise direction in response to rotation of shaft 22 by ratchet wheel 30. Ratchet bracket 25 YVis shown lin its reference position in FIGURES 2 and 3 with coil 10 de-energized and armature 15 in its rest position.

The bias of spring 47 on ratchet bracket 25 also serves to hold armature 15 in its rest position by means of drive rod 41 engaging adjusting screw 44. Upon energization or coil 1?, armature 15 is pivoted toward pole piece 13, thus pushing drive rod 41 to the left (as seen in FIGURE 4) and rotating ratchet bracket 25 in a counterclockwise direction. During this rotation, herein termed the return stroke, straight portion 37 of ratchet spring 35 is cammed downwardly by the action of a ratchet tooth to the position shown by the dashed ylines in FIGURE 3. When ratchet bracket 25 reaches its extreme counterclockwise position, as shown in FIGURE 4, straight portion 37 of the ratchet springrdrops into engagement wtih a preceding tooth. During this motion, backward movement of ratchet wheel 39 is prevented by pawl 29.

Upon de-energization of coil 10 return spring 47 Yrestores bracket 25 to its rest position to cause ratchet spring 35 to advance ratchet wheel 3i), shaft 22, and wiper arm 17 one step.

It is apparent that the major work accomplished by the relay isY in rotating ratchet bracket 25 from its rest position to an actuating position. overcome the bias of return spring 47 thereby storing energy in it and also overcome the upward bias of straight portion 37 or the ratchetspring.Y Since the moving of ratchet spring 35 is all wasted energy, the minimization of this energy loss will produce a highly sensitive relay.

The design of ratchet spring 35 as disclosed in the present application greatly reduces energy loss as compared to prior art ratchet relays. Thus, an improved ratchet relay is disclosed having a high sensitivity making its utilization with transistorized actuating device practical. In addition, a relay of simple and inexpensive construction has been provided. f Y,

While a particular embodiment'of the invention has been shown and described, it will be obvious to those.

skilled in the art that changes and modications may be made without departing from the invention in itsrbroader aspects, and, therefore, the aim in the appended claims is to cover all such changes and modifications as fallV legs on opposite sides of said ratchet wheel, each of said legs having a guide channel of predetermined width extending radially outwardly from said shaft; a ratchet spring retained by said bracket, such spring having a main portion of a thickness corresponding to said predetermined width ot said guide channels extendingthrough said guide channelsrin a direction substantially parallel to said shaft, said main portion being captivated against relative movement perpendicular to said radial direction by said guide channels but free to move within said channels in said radial direction, and said main portion being biased into engagement with said ratchet Wheel;

and means for rotating said ratchet bracket andv said ratchet spring to advance said ratchet'wheel and rotate .said shaft.

. A high sensitivity ratchet relay comprising:

supporting frame;

shaft journalled in said frame;

ratchet bracket pivoted on said shaft and having a bight portion and two legs through which the shaft extends, each of said legs having a guide slot of predetermined width extending radiallyV outwardly from said shaft, said ratchet wheel being xed lto said shaft between said legs;

a wire ratchet spring having a multiple loop portion and a straight portion oi a thickness corresponding to said predetermined width of saidguide slots coupled to one end of said multiple loop Vportion and extending through and retained in said slots in said two legs in a direction substantially parallel to said shaft, said straight portion being captivated against relative movement perpendicular to said radial direction by said guide slots but free to move within said slots in said radial direction, such straight Vportion being biased into engagement with said ratchet wheel by said multiple loop portion, the other end of said multiple loop portionk being fulcrumed on said bracket at a point more remote from said wheel than said straight portion;

and means for rotating said ratchet bracket and said ratchet spring to advance said ratchet wheel and rotate said shaft. n Y

To accomplish this, it mustv ratchet wheel mounted for rotation with said shaft;y

3. A high sensitivity ratchet relay comprising:

a supporting frame;

a shaft journalled in said frame;

a ratchet Wheel mounted for rotation with said shaft;

a ratchet bracket pivoted on said shaft and having a bight portion and two legs through which the shaft extends, each of said legs having a guide slot of predetermined Width extending in a radial direction relative to said shaft, said ratchet wheel being ixed to said shaft between said legs;

a ratchet assembly including a resilient Wire loop portion and a straight portion of a thickness corresponding to said predetermined Width of said guide slots having two ends extending through and retained in said slots in a direction substantially parallel to said shaft, such straight portion being biased into engagement with said ratchet Wheel by said resilient Wire loop portion;

means including an actuating coil and an armature coupled to said ratchet bracket for displacing said ratchet bracket from a rest position;

said resilient Wire loop portion being ulcrumed on and return means for restoring said bracket to said rest position to cause said ratchet assembly to advance said ratchet Wheel and rotate said shaft.

References Cited in the tile of this patent UNITED STATES PATENTS 2,572,989 Contant et al. Oct. 30, 1951 2,704,944r Hughes et al Mar. 29, 1955 2,705,428 McCullough Apr. 5, 1955 2,897,680 Fritsch Aug. 4, 1959 2,997,840 Rueger Aug. 29, 1961 3,041,818 Jensen July 3, l962

Claims

1. A HIGH SENSITIVITY RATCHET RELAY COMPRISING: A SUPPORT FRAME; A SHAFT JOURNALLED IN SAID FRAME; A RATCHET WHEEL MOUNTED FOR ROTATION WITH SAID SHAFT; A RATCHET BRACKET PIVOTED ON SAID SHAFT AND HAVING TWO LEGS ON OPPOSITE SIDES OF SAID RATCHET WHEEL, EACH OF SAID LEGS HAVING A GUIDE CHANNEL OF PREDETERMINED WIDTH EXTENDING RADIALLY OUTWARDLY FROM SAID SHAFT; A RATCHET SPRING RETAINED BY SAID BRACKET, SUCH SPRING HAVING A MAIN PORTION OF A THICKNESS CORRESPONDING TO SAID PREDETERMINED WIDTH OF SAID GUIDE CHANNELS EXTENDING THROUGH SAID GUIDE CHANNELS IN A DIRECTION SUBSTANTIALLY PARALLEL TO SAID SHAFT, SAID MAIN PORTION BEING CAPTIVATED AGAINST RELATIVE MOVEMENT PERPENDICULAR TO SAID RADIAL DIRECTION BY SAID GUIDE CHANNELS BUT FREE TO MOVE WITHIN SAID CHANNELS IN SAID RADIAL DIRECTION, AND SAID MAIN PORTION BEING BIASED INTO ENGAGEMENT WITH SAID RATCHET WHEEL; AND MEANS FOR ROTATING SAID RATCHET BRACKET AND SAID RATCHET SPRING TO ADVANCE SAID RATCHET WHEEL AND ROTATE SAID SHAFT.