US3824353A

US3824353A - Hook-switch cradle assembly for electrical communication handset

Info

Publication number: US3824353A
Application number: US00298871A
Authority: US
Inventors: W Howe; B Buell
Original assignee: VOYCALL
Current assignee: VOYCALL
Priority date: 1972-10-19
Filing date: 1972-10-19
Publication date: 1974-07-16
Anticipated expiration: 1991-07-16

Abstract

A hook-switch type cradle assembly for use with an electrical communication handset providing reduced sensitivity to spurious undesired signals caused by accidental or intentional ''''teasing'''' and a reduced susceptability to ''''bouncing'''' is disclosed. An embodiment of the invention is described in which microswitches are utilized and in which the mass in motion during operation is reduced as compared to prior art. Various embodiments of the mechanical components for accomplishing the objects of this invention are disclosed.

Description

United States Patent [191 Howe et al.

[111 3,824,353 [451 Jul 16, 1974 [75] Inventors: William E. Rowe, Orinda; Bruce A.

Buell, Walnut Creek, both of Calif. [73] Assignee: Voycall, Oakland,'Calif. [22] Filed: Oct. 19, 1972 [21] Appl. No.: 298,871

[52] US. Cl. .[179/164 [51] Int. Cl. H04m 1/08 [58] Field of Search 179/159, 164

[56] References Cited UNITED STATES PATENTS 3,027,432 3/1962 Jordan et al. 179/164 3,440,366 4/1969 Samios 179/164 7 HOOK-SWITCH CRADLE ASSEMBLY FOR ELECTRICAL COMMUNICATION HANDSET Primary Examiner-William C. Cooper Attorney, Agent, or Firm-Phillips, Moore, Weissenberger, Lempio & Strabala 57 ABSTRACT A hook-switch type cradle assembly for use with an electrical communication handset providing reduced sensitivity to spurious undesired signals caused by accidental or intentional teasing and a reduced susceptability to bouncing is disclosed. An embodiment of the invention is described in which microswitches are utilized and in which the mass in motion during operation is reduced as compared to prior art. Various embodiments of the mechanical components for accomplishing the objects of this invention are disclosed.

11 Claims, l0-Drawing Figures mmmmw 3.824.353

SHEET 2 BF 3 FIG 4 FIG 3 I POS CRADLE ARM TRAVEL 2nd POS FIG;6 f

BACKGROUND OF THE INVENTION This invention relates to a hook-switch cradle assembly for use with an electrical communication handset and more particularly to a hook-switch cradle assembly with reduced sensitivity to accidental or intentional teasing" and a reduced susceptibility to bouncing. For the purposes of this patent, teasing is defined as any combination of partial actuations or full actuations of the hook-switch, usually repeated more than once, in such a way as to produce undesired operation of the electrical communication system of which the handset is a part, as by erratic movements of the hook-switch cradle arm in its normal travel. Similarly, bouncing is defined as oscillatory mechanical movementof the cradle arm due to the combined effects of its mass, the spring mechanism by which it is mounted and the forces to which it is subjected in use.

In electrical communication systems, such as the'telephone system for example, it is customary to provide a handset including at least a transmitting microphone and usually a receiving speaker for utilization of the system. For convenience, a cradle for supporting the handset is also provided and an electrical switch means is associated with the cradle in such a way that the handset is electrically disconnected from the system by the switch means when supported by the cradle and automatically connected to the system through the switch means when removed from the cradle. The switch means usually includes a number of separate pairs of contacts which must make or break contact in a given sequence for proper operation of the system.

In an ordinary telephone instrument where the handset is supported on a rigid cradle and the switch means is operated by buttons projecting through the rigid cradle to be contacted by the handset there is little chance for improper operation of the switch means. The buttons are well protected and have small mass. The use of bifurcated leaf type switches with elongated leaves provides for a relatively large amount of movement of the parts of the switch means in which to accomplish the precise sequence in the operation of the switch means. It is, of course, possible to intentionally tease the switch means of an ordinary telephone instrument by removing the handset from thecradle and moving the buttons through portions of their travel manually. It is possible to simulate dialing of the telephone in this manner and it is common to flash the operator by simulating the repeated replacement and removal of the handset. However, accidental teasing of the switch means is unlikely to occur in the conventional telephone instrument because the buttons are well protected and have very low mass as mentioned above. The fact that the buttons have low mass and that a large amount of movement thereof is required to operate the switch mehcanism obviates any problems due to bouncing" of the mechanism.

In many modern telephone instruments, and in electrical communication systems other than telephone systems, it has been found convenient to use a hookswitch cradle assembly in place of the rigid cradle and button switch assembly described above in order to make the handset more accessible by locating it outboard of the instrument (i.e., on the front, back or sides 2 rather than on top of the instrument). In a hook-switch cradle assembly, a pivoted cradle arm is provided to support the handset when not in use. The cradle arm pivots or rotates about a fulcrum between a first position when the handset is supported thereby and a second position when the handset is removed. Such rotary movement of the cradle arm is used to operate a switch means which disconnects the handset from the commu: nication system when the cradle arm is in its first position and connects it to the system when the cradle arm is in its second position. Thus, the operation of the cradle arm is similar to the buttons of the conventional telephone instrument except that such arm has much more mass than the buttons. Such increased mass requires the use of stronger springs and makes it much more likely that bouncing of the switch means will occur due to the combined effects of the larger mass and the greater spring forces. Such combined effects include the dissipation of energy in bouncing due to impact and in oscillatory movements of the hook-switch cradle arm. Since the same bifurcated leaf type switch means have been used in hook-switch cradle assemblies as are used in ordinary cradle assemblies the sensitivity of the hook-switch cradle assembly to intentional or accidental teasing is increased. Finally it is difficult to shield the cradle arm from the accidental impacts which can actuate the switch means.

It is an object of this invention to provide a hookswitch'cradle assembly for the handset of an electrical communication system which has reduced sensitivity to intentional or accidental teasing and a reduced susceptibility to bouncing in operation.

It is a further object of this invention to provide a hook-switch cradle assembly for use with the handset of anelectrical communication system in which the required sequence of operation of the switch means occurs during a small part of the travel of the cradle arm thereof.

It is another object of this invention to provide such a hook-switch cradle assembly in which snap action switches maybe used as the switch means thereof.

It is yet another object of this invention to provide such a hook-switch cradle assembly in which the mass in motion during operation thereof is reduced.

It is a still further object of this invention to provide such a hook-switch cradle assembly in which the precise sequence of operation of the switch means may be quickly and easily adjusted.

SUMMARY OF THE INVENTION A hook-switch cradle assembly according to this invention includes a spring means exerting force on the cradle arm urging it to depart from the first position thereof, which force is maximum when the cradle arm is in a position intermediate the first and second positions thereof and decreases as the cradle arm departs from such intermediate position toward the second position thereof; and auxiliary means exerting force on the cradle arm urging it to depart from the first position, which force is minimal when the cradle arm is in such intermediate position and increases as the cradle arm departs from such intermediate position toward the second position thereof. The total force exerted by the spring means and auxiliary means on the cradle arm is at all times less than the weight of the handset and greater than the unbalanced weight of the cradle arm about the fulcrum on which it is mounted and the 3 7 switch means being actuated by the travel of the cradle arm between such intermediate position and the second position thereof.

BRIEF DESCRIPTION OF THE DRAWING The foregoing and other objects and features of the invention will be more fully understood by reading the following detailed description of preferred embodiments of this invention in conjunction with the appended drawing wherein:

FIG. 1 is a cross-sectional view of an instrument including a hook-switch cradle assembly and handset for an electrical communication system according to one embodiment of this invention with portions of the housing of the instrument shown in phantom.

FIG. 2 is a fragmentary top view of the instrument of FIG. 1 showing the hook-switch cradle assembly but with the handset shown in phantom.

FIG. 3 is a cross-sectional view of the hook-switch cradle assembly taken along line 3-3 of FIG. 2 with the handset shown in phantom and the cradle arm thereof in its first position.

FIG. 4 is a view identical to FIG. 3 but with the handset removed and the cradle arm thereof in its second position.

FIG. 5 is a side view in elevation of a conventional microswitch suitable for use in embodiments of this invention.

FIG. 6 is a graphical representation of the mechanical bias forces exerted on the cradle arm of the hookswitch cradle assembly of FIGS. l4 at various points in its travel between the first and second positions thereof.

FIG. 7 is a fragmentary top view of an instrument including a hook-switch cradle assembly in accordance with a further embodiment of this invention.

FIG. 8 is a view taken along lines 8-8 of FIG. 7 showing the cradle arm and actuator arm of the assembly in their firstposition.

FIG. 9 is a view identical to FIG. 8 but showing the cradle arm and actuator arm in their second position.

) FIG. 10 is a graphical representation of the mechanical bias forces exerted on the cradle arm of FIGS. 7- -9 at various points in its travel between the first and second positions thereof.

DESCRIPTION OF PREFERRED EMBODIMENTS Referring to FIGS. 1 and 2 a hook-switch cradle assembly 10 according to one embodiment of this invention is shown mounted at one end of the chassis II of a telephone intercommunication instrument. It will be understood that such chassis 11 is a shallow rectangular pan preferably made out of metal. The other electrical, mechanical and electronic components of the instrument (not shown) may also be mounted on such chassis 11 or on an appropriate housing 12 or cover indicated in phantom in FIG. 1 as affixed to the top of the chassis l l.

The hook-switchcradle assembly 10 is mounted on the chassis 11 by means of bolts 13, for example, and according to this embodiment of the invention comprises a mounting plate 14 having a switch mounting bracket 15 and a fulcrum or pivot bracket 16 projecting from one of its major surfaces. It will be understood that the switch-mounting bracket 15 and fulcrum .bracket 16 may be made as a single unit and secured cure the mounting plate to the chassis 11. A rod or axle 18 is passed through the fulcrum bracket 16 and a cradle 20 for a telephone handset is pivotably mounted on such axle 18. j

The cradle 20 comprises a pair of

cradle arms

21 and 22 extending outwardly of the chassis 11 through appropriate slots 23. Each of the

elongated cradle arms

21 and 22 have one end attached to a hinged pivot plate 25, the other or free ends thereof being appropriately shaped to receive and support a telephone handset 30. The pivot plate 25 may be pivotably mounted on the axle 18 by means of

appropriate hinge members

26 and 27 which may be formed integrally with the pivot plate 25.

As best shown in FIG. 1 the telephone handset 30 is electrically connected by means of an appropriate multi-conductor electrical cord 31 to a plurality of

switches

32, 33, and 34 mounted on the switch-mounting bracket 15.The

switches

32, 33, and 34 are preferably of the snap action type commonly known as microswitches and are in turnelectrically connected through other electrical components (not shown) of the instrument to an appropriate communication system such as a telephone network, for example.

According to this embodiment of the invention an actuator arm bracket 40 is mounted on the pivot plate 25 by means of screws 41 (FIG. 2) and extends therefrom in the direction opposite from the direction in which the

cradle arms

21 and 22 extend. The actuator arm 40 includes a portion which is adapted to mechanically engage the

switches

32,33, and 34 as by means of

setscrews

42, 43, and 44 mounted on the actuator arm 40, for example.

A spring means 45 according to the teaching of this invention is mounted on an extension 46 of the fulcrum bracket 16 and adapted to bear on an extension 47 of the actuator arm 40 as shown in FIGS. 1 and 2. In addition, an auxiliary actuation means 50 according to the teaching of this invention is mounted on the actuator arm 40 in the embodiment of the invention shown in FIGS. 1 and 2. The form and function of the spring means 45 will be more fully described in connection with FIGS. 3 and 4 as will the function of the auxiliary actuation means 50. However, the form of auxiliary actuation means 50 according to this embodiment of the invention is best shown in FIGS. 1 and 2 and comprises an annular magnet 51 mounted on the actuator arm 40 by means of a bolt 52 with a pair of pole pieces 43 on opposite sides thereof. It will be understood that in this embodiment of the invention the mounting plate 14 is made of magnetic material for interaction with the magnetic field established between the pole pieces 53 by the magnet 51.

Referring to FIG. 3 it will be seen that when the telephone handset 30 is received on the free ends of the

cradle arms

21 and 22, its weight will tend to cause the cradle to rotate counterclock wise about the axle 18 on which it is pivoted. Since the actuator arm 40 is mounted on the pivot plate 25 of the cradle 20, it will also rotate counterclock wise about the axle 18 when the telephone handset 30 is received on the free ends of the cradle arm. Such rotation will continue until the pivot plate 25 abuts the fulcrum bracket 16. Thus, the various elements of the assembly as shown in FIG. 3 are in their first" position referred to hereinabove.

It will be seen that when the elements of the hookswitch-cradle assembly are in their first position as shown in FIG. 3 the

setscrews

42, 43, and 44 are rotated out of engagement with the switch means 32, 33, and 34. Thus, the

switches

32, 33, and 34 are open and the handset 30 is disconnected from the communication system by such switches.

It will also be seen that the auxiliary actuation means 50 is rotated away from the mounting plate 14. According to the teaching of this invention the magnet 51 and pole pieces 53 of the auxiliary actuation means 50 are designed to produce an intense but highly localized field. Thus, the force of magnetic attraction between the auxiliary actuation means 50 and the mounting plate 14 is minimal when they are separated by a distance even less than that shown in FIG. 3.

Referring now to the special spring means utilized according to the teaching of this invention, it will be seen that such spring means 45 has a U-shape cross-section in FIGS. 3 and 4. The spring member 45 is designed so that the spacing between the free ends of such U-shape in their common plane when the spring is untensioned is slightly greater than the spacing between the fulcrum bracket extension 46 and the actuator extension 47. Thus, the spring member 45 must be slightly flexed in order to mount it between

extensions

46 and 47. It will be understood that the free ends of the spring 45 are free to rotate about parallel axes corresponding to their respective abutments with extension 46 and extension 47. Due to the fact that the spring 45 is slightly flexed, the force of the spring urges such parallel axes to move away from each other in their common plane. The resulting force includes a vector tending to cause the actuator arm to rotate about the axle 18. The plane of the common axes of abutment of the free ends of the U- shape spring 45 with the

extensions

46 and 47, respectively, is selected so that such vector force tends to cause the actuator arm to rotate clockwise about the axle 18. In addition, according to the teaching of this invention, this position and spacing of the axes of abutment of the free ends of the U-shape cross-section of spring 45 with the

extensions

46 and 47, respectively, from the axle 18 is such that the vector force exerted by the spring 45 tends to increase to a maximum and then decrease as the actuator arm rotates clockwise about the axle 18 from the first position shown in FIG. 3 to the second position shown in FIG. 4. It will be understood that the vector force tending to produce clockwise rotation of the actuator arm 40 and cradle 20 must be less than the weight of the telephone handset but greater than the unbalanced weight of the cradle arm 20 and actuator arm when the elements of the assembly are in the position shown in FIG. 3. Thus, when the telephone handset 30 is removed from the cradle 20 the vector force exerted by the spring will tend to rotate the actuator arm 40 and cradle 20 clockwise about the axle 18 tending to cause the elements of the assembly to assume the position shown in FIG. 4.

Referring to FIG. 4, it will be understood that as the elements of the assembly approach the position shown, the auxiliary actuation means is brought into ever closer proximity to the mounting plate 14. Thus, the magnetic attraction between the actuator means 50 and the mounting plate 14 resulting from the magnetic field between the pole pieces 53 will tend to increase exponentially to its maximum value when the pole pieces 53 are in contact with the mounting plate 14 stopping further clockwise rotation. According to the teaching of this invention the spring 45 and the axes of rotation at the abutment between the ends thereof and the

extensions

46 and 47 are designed to result in a reduced force vector tending to cause clockwise rotation of the actuator arm 40 and cradle 20 as the elements of the assembly approach the position shown in FIG. 4.

It will be understood that the combined force of the auxiliary actuating means 50 and the spring 45 tending to produce clockwise rotation thereof when the elements of the assembly are in the position shown in FIG. 4 must be less than the weight of the telephone handset when combined with the unbalanced weight of the cradle 20 and actuator arm 40. However, such combined force of the spring 45 and auxiliary actuation means 50 must be sufficient to overcome the resistance of the switch means to the clockwise rotation of the actuator arm 40.

According to the teaching-of this-invention, the tendency of the elements of the cradle assembly to bounce or oscillate with respect to the second position thereof as shown in FIG. 4 is greatly reduced. In the first place,

the magnetic force exerted by the auxiliary actuation means 50 may be quite substantial when the cradle assembly is in its second position. But it is even more important that such force has been exerted over a fairly small portion of the travel of the elements of the assembly. This coupled with the fact that the vector force tending to cause clockwise rotation, of the elements of the cradle assembly into the position shown in FIG. 4 exerted by the spring 45 decreases as such elements approach such position tends to result in the minimum required acceleration of the elements of the assembly in moving from the first position thereof shown in FIG. 3 to the second position thereof shown in FIG. 4. The net result of the abovementioned factors will be a reduced impact of. the pole pieces 53 on the base plate 14 and a reduced tendency of the elements of the assembly to bounce oroscillate away from the position shown in FIG. 4. Furthermore, according to the teaching of this invention, it is desirable to make the cradle of aluminum or some other lightweight material in order to reduce the mass in motion and the resulting impact when the elements of the cradle assembly move from the first position shown in FIG. 3 to the second position thereof shown in FIG. 4. i

The above-described reduced tendency of the elements of the cradle assembly to bounce or oscillate about the position shown in FIG. 4 is an important aspect of this invention in that it decreases the likelihood that the switch means 32, 33, and 34 will be actuated more than once and other than in the sequence desired. Such reduced tendency to bounce becomes even more important in view of the structural features taught by this invention in order to avoid intentional or accidental teasing of the switch means.

According to the preferred embodiment of this invention the switch means utilized are snap action switches of the type commonly known as microswitches. Referring to FIG. 5, the structural details of a microswitch 32 suitable for use in embodiments of this invention are shown. Such microswitch may comprise a plastic body having snap action switch elements sealed therein. A button 56 for actuating the snap action switch elements projects through the housing and into contact with a cantilever spring member 57. It will be understood that the snap action switch elements are 7 designed to make electricalconnection between the terminals 58 when a certain amount of force is exerted on the button 56. In normal operation, a force indicated by the arrow 59 is exerted on the end of the cantilever member 57. This in turn exerts a force on the button 56 tending to actuate the snap action switch elements. The cantilever spring member 57 is utilized in order to allow a certain range of overtravel in the operation of the microswitch 32. Thus, when the force indicated by the arrow 59 reaches a certain level, it will first cause the button 56 to be depressed into its housing 55 actuating the snap action switch member-and will then result in bending of the cantilever member 57.

According to the teaching of this invention each of t the

setscrews

42, 43, and 44 exert a force 59 on the cantilevermember 57 of a different one of the

microswitches

32, 33, and 34. The

setscrews

42, 43, and 44 are adjusted in their projection through the actuator arm 40 with respect to each other in order to produce a desired sequence of operation of the

microswitches

32, 33, and 34. Thus, it will beseen that the cantilever member 57 of certain of the

switches

32, 33, and 34 will be flexed more than others in order to provide a still possible to actuate them repeatedly in their desired sequence in order to flash" the operator, for example.

The operation of this embodiment of the invention will be better understood by reference to FIG. 6 in which such operation is graphically represented. In such graph the travel of the cradle arm is plotted on the abscissa from its first position (shown in FIG. 3) on the right to its second position (shown in FIG. 4) on the left. Units of force are plotted on the ordinate of such graph and curve 45 'jrepresents the force exerted by the spring member 45 on the cradle arm during its travel between the first and second positions thereof. Similarly, the curve labeled 50' indicates the force exerted on the cradle arm by the auxiliary actuation means during the travel of the cradle arm from the first to thesec- 0nd position thereof. The vertical dotted line on the graph represents the start of the operating range of travel of the cradle arm (designated by the bracket la- 8 susceptible to bouncing effects. Furthermore, the fact that the sequential operation of the switch means occurs only during a fairly small fraction of the travel of the cradle arm as it approaches its second position makes it extremely difficult to tease the switch mechanisrn, that is, to operate the

switches

32, 33, and 34 other than in the desired sequence of operation.

Referring to FIGS. 7-9 another embodiment of this invention is shown which enables the cradle arm to move through a portion of its travel adjacent its second position independently of the actuator arm. This embodiment is identical to the embodiment shown in FIGS. [-4 except that an actuator arm bracket 40', provided with hinge members 48, is mounted on the axle 18 independently of the pivot plate 25 and a coil spring 70 having one end bearing on the pivot plate 25 and the other end bearing on the fulcrum bracket 16 is beled A in FIG. 5) during which the

switches

32, 33,

' and 34 is additive with slight aberrations produced as the snap action mechanism of each switch is operated. It will also be seen that the exponential increase in the force exerted by the magnetic field of the auxiliary actuation means very nearly matches the additive resistances of theswitch means 32, 33,and 34. This is highly desirable according to the teaching of this invention since such matching of increasing force exerted by v the auxiliary actuation means and increasing resistance of the switch means tends to make the assembly less mounted about the axle 18 to urge rotation of the eradle 20 in a clockwise direction as shown in FIGS. 8 and 9. FIGS. 8 and 9 are similar to FIGS. 3 and 4, except that they are both taken along lines 8-8 of FIG. 7 and a portion of the cradle arm 22 is: broken away. The parts shown in FIGS. 7-9-which arethe same as parts shown in FIGS. 1-4 are identified by the same reference numerals.

The difference in operation between the embodiment of this invention shown in FIGS, 7-9 from that shown in FIGS. 1-4 is graphically shown by a comparison of FIG. 10 tofFIG. 5. Identical curves in FIGS. 10 and 5 have been given the same reference numeral. However, in FIG. 10 a new curve representing the force exerted on the cradle'arm 20 by the spring 70 has been added and the graph has been extended to the right to represent the additional travel of the cradle arm 20 provided by the. embodiment of the invention shown in FIGS. 7-9.

Thus, as shown in FIG. 8, the spring 45 and the auxiliary means 50 exert force on the actuator arm bracket 40 urging it into abutment with the pivot plate 25 when the assembly is in its first position. As shown at the left ofFIG. 10, such abutment results in the cooperation of the force of the spring 45 and auxiliary means 50 with the force of the spring 70 in urging both the actuator arm bracket 40 and the cradle 20 to rotate in a clockwise direction toward the second position thereof shown in FIG. 9. However, before the cradle arm 20 can reach the limit of its travel toward its second position, the pole pieces 53 of the auxiliary means 50 contact the mounting plate 14 prohibiting further clockwise rotation of the actuator arm bracket 40. This, of course, immediately removes the force of the spring 45 and auxiliary means 50 from the cradle arm 20 and further clockwise rotation of the cradle arm occurs under the influence of the spring 70 alone as shown atthe right of FIG. 10.

The spring 70 is designed to exert a force urging clockwise rotation of the cradle 20 which decreases to a value substantially equal to the unbalanced weight of the cradle 20 as the cradle 20 approaches its second position. Thus, the cradle 20 will tend to continue to rotate in a clockwise direction after rotation of. the actuator arm bracket 40 has been stopped, moving the pivot plate 25 out of abutment withthe actuator arm bracket 40 as shown in FIG. 9. The net result is to place the relatively narrow operating range A, during which the

switches

32, 33,-and 34 are actuated, toward the center of the range of travel of the cradle arm 20 and remove the operating range A from the range of oscillatory mechanical movement of the parts of the assembly which tend to occur at the first and second positions thereof due either to bouncing or teasing of the assembly. In addition, the mass of the cradle arm 20 is mechanically dissociated from the actuator arm bracket 40 at the end of the operating range A when it approaches its second position resulting in the damping of mechanical oscillations due to bounce effects.

It is anticipated that those skilled in the art may make various obvious modifications in the structures of the preferred embodiments of this invention as shown in the drawing and described hereinabove. Specifically, the mechanical elements of the invention may be reversed in their operation without changing their function, as by mounting the switches for movement with the cradle arm into mechanical contact with fixed actuating means. Similarly, various mechanical and magnetic devices, other than those shown and described herein, may be used to apply to required forces urging rotation of the parts of the assembly, as described, and the relative location of the'fulcrum about which different parts of the assembly may rotate may obviously be changed as desired without departing from the teaching of this invention.

What is claimed is:

1. A hook-switch cradle assembly for use with an electrical communication handset comprising:

a. a hook-switch cradle arm support means;

b. an electrical switch means electrically connected to said handset comprising a plurality of snapaction switches each in a sealed housing;

c. actuation means including a plurality of setscrews each adapted to actuate a different one of said plurality of said snap-action switches by mechanical engagement therewith, said setscrews each being mounted for adjustment toward and away from said snap-action switches along thepath of mechanical engagement between said setscrews and said snap-action switches;

d. a hook-switch cradle arm having one end adapted to removably support said handset and being mounted on said support means for rotation through a given angle about a fulcrum between a first position when said handset is supported thereon and a second position when said handset is removed therefrom, said switch means and said actuation means being mechanically coupled to said cradle arm for movement of one of said means thereby to actuate said switch means when said cradle arm moves through a portion of its travel from said first position to said second position thereof;

e. first means adapted to exert mechanical force on said cradle arm urging said cradle arm to depart from said first position thereof, said force exerted by said first means decreasing as said cradle arm departs from an intermediate position toward said second position thereof; and auxiliary means adapted to exert mechanical force on said cradle arm urging said cradle arm to depart from said first position thereof, said force exerted by said auxiliary means on said cradle arm being small when said cradle arm is in said intermediate position and increasing as said cradle arm departs from said intermediate position toward said second position thereof, the total force exerted on said cradle arm by said first means and said auxiliary means being at all times less than the weight of said handset and at least equal to the unbalanced weight of said cradle arm about said fulcrum. 2. A hook-switch cradle assembly as claimed in claim 1 wherein said electrical switch means is mounted on said support means and said actuation means is mounted on said cradle arm for mechanical engagement with said switch means.

3. A hook-switch cradle assembly as claimed in claim 2 including a plurality of snap-action switches each adapted to be actuated by a different one of a plurality of setscrews mounted on said cradle arm.

4. A hook-switch cradle assembly as claimed in claim 2 wherein said fulcrum is located intermediate the ends of said cradle arm with said actuation means mounted on said cradle arm on the opposite side of said fulcrum 4 wherein said auxiliary means is mounted on said cradle arm on the opposite side of said fulcrum from said one end of said cradle arm.

7. A hook-switch cradle assembly as claimed in claim 1 wherein said first means comprises a spring member of U-shape cross-section in the plane of rotation of said cradle arm with the end portion of one leg thereof being mounted on said support means for rotation about a first axis parallel to and spaced from the axis of said fulcrum and the end portion of the other leg thereof being mounted for rotation about a second axis parallel to and spaced from said first axis and bearing on said cradle arm at a point spaced from said fulcrum, said first axis and said second axis approaching each other in a common plane when said cradle arm approaches said position intermediate said first and second positions thereof.

8. A hook-switch cradle assembly as claimed in claim 1 wherein said auxiliary means comprises a first magnetic member mounted on said actuation means and adapted to approach a second magnetic member mounted on said support means as said cradle arm moves toward said second position thereof.

9. A hook-switch cradle assembly as claimed in claim 1 wherein the total weight mounted for rotation about said fulcrum is substantially less than the weight of said handset.

10. A hook-switch cradle assembly for use with an electrical communication handset comprising: a. a hook-switch cradle arm support means; b. an electrical switch means electrically connected to said handset; t c. a hook-switch cradle arm having one end adapted to removably support said handset and being mounted on said support means for rotation through a given angle about a fulcrum between a first position when said handset is supported thereon and a second position when said handset is removed therefrom; d. actuation means mechanically coupled to said cradle arm for movement to thereby actuate said switch means when said cradle arm moves through i a portion of its travel from said first position to said second position thereof, said actuation means com- 11 prising an actuation arm mounted independently of said cradle arm for rotation through a given angle about said fulcrum between a first position and a' first means adapted to exert mechanical force on said cradle arm urging said cradle arm to depart from said first position thereof, said force exerted by said first means decreasing as said cradle arm departs from an intermediate position toward said second position thereof;

. auxiliary means adapted to exert mechanical force on said cradle arm only during simultaneous rotation of said cradle arm and said actuator arm urging said cradle arm to depart from said first position thereof, said force exerted by said auxiliary means on said cradle arm being minimal when said cradle arm is in said first position and increasing during simultaneous rotation of said cradle arm and said actuator arm; and

g. second means adapted to exert mechanical force only on said cradle arm to urge said'cradle arm to rotate to said second position thereof, the total force exerted on said cradle arm by said first means, said auxiliary means and said second means being at all times less than the weight of said handset and at least equal to the unbalanced weight of said cradle arm about said fulcrum.

11. A hook-switch cradle assembly as claimed in claim 10 wherein said actuation means includes a setscrew mounted on said actuator arm for engagement with said switch means.

Claims

1. A hook-switch cradle assembly for use with an electrical communication handset comprising: a. a hook-switch cradle arm support means; b. an electrical switch means electrically connected to said handset comprising a plurality of snap-action switches each in a sealed housing; c. actuation means including a plurality of setscrews each adapted to actuate a different one of said plurality of said snap-action switches by mechanical engagement therewith, said setscrews each being mounted for adjustment toward and away from said snap-action switches along the path of mechanical engagement between said setscrews and said snap-action switches; d. a hook-switch cradle arm having one end adapted to removably support said handset and being mounted on said support means for rotation through a given angle about a fulcrum between a first position when said handset is supported thereon and a second position when said handset is removed therefrom, said switch means and said actuation means being mechanically coupled to said cradle arm for movement of one of said means thereby to actuate said switch means when said cradle arm moves through a portion of its travel from said first position to said second position thereof; e. first means adapted to exert mechanical force on said cradle arm urging said cradle arm to depart from said first position thereof, said force exerted by said first means decreasing as said cradle arm departs from an intermediate position toward said second position thereof; and f. auxiliary means adapted to exert mechanical force on said cradle arm urging said cradle arm to depart from said first position thereof, said force exerted by said auxiliary means on said cradle arm being small when said cradle arm is in said intermediate position and increasing as said cradle arm departs from said intermediate position toward said second position thereof, the total force exerted on said cradle arm by said first means and said auxiliary means being at all times less than the weight of said handset and at least equal to the unbalanced weight of said cradle arm about said fulcrum.

2. A hook-switch cradle assembly as Claimed in claim 1 wherein said electrical switch means is mounted on said support means and said actuation means is mounted on said cradle arm for mechanical engagement with said switch means.

4. A hook-switch cradle assembly as claimed in claim 2 wherein said fulcrum is located intermediate the ends of said cradle arm with said actuation means mounted on said cradle arm on the opposite side of said fulcrum from one end of said cradle arm.

5. A hook-switch cradle assembly as claimed in claim 4 wherein said first means exerts force on said cradle arm on the opposite side of said fulcrum from said one end of said cradle arm.

6. A hook-switch cradle assembly as claimed in claim 4 wherein said auxiliary means is mounted on said cradle arm on the opposite side of said fulcrum from said one end of said cradle arm.

10. A hook-switch cradle assembly for use with an electrical communication handset comprising: a. a hook-switch cradle arm support means; b. an electrical switch means electrically connected to said handset; c. a hook-switch cradle arm having one end adapted to removably support said handset and being mounted on said support means for rotation through a given angle about a fulcrum between a first position when said handset is supported thereon and a second position when said handset is removed therefrom; d. actuation means mechanically coupled to said cradle arm for movement to thereby actuate said switch means when said cradle arm moves through a portion of its travel from said first position to said second position thereof, said actuation means comprising an actuation arm mounted independently of said cradle arm for rotation through a given angle about said fulcrum between a first position and a second position; said given angle of rotation of said actuator arm being a portion of said given angle of rotation of said cradle arm with said first position of said actuator arm coinciding with said first position of said cradle arm, said cradle arm and said actuator arm being mechanically coupled to each other only during rotation through said given angle of rotation of said actuator arm with said first means; e. first means adapted to exert mechanical force on said cradle arm urging said cradle arm to depart from said first position thereof, said force exerted by said first means decreasing as said cradle arm departs from an intermediate position toward said second position thereof; f. auxiliary means adapted to exert mechanical force on said cradle arm only during simultaneous rotation of said cradle arm and said actuator arm urging said cradle arm To depart from said first position thereof, said force exerted by said auxiliary means on said cradle arm being minimal when said cradle arm is in said first position and increasing during simultaneous rotation of said cradle arm and said actuator arm; and g. second means adapted to exert mechanical force only on said cradle arm to urge said cradle arm to rotate to said second position thereof, the total force exerted on said cradle arm by said first means, said auxiliary means and said second means being at all times less than the weight of said handset and at least equal to the unbalanced weight of said cradle arm about said fulcrum.