CH250694A - Force limiting device acting on the transmission components mechanically connecting the pick-up arm of a talking machine to its control components. - Google Patents

Description

Force limiting device acting on the transmission members mechanically connecting the pick-up arm of a speaking brake to its control members. :_ In the speaking jaws provided with a mechanism causing the automatic change of the discs, the 1st arm of the picli#-up is generally actuated by: control devices pro.vequant its vertical and horizontal displacements according to a determined cycle.

In all known machines of this type, the order of magnitude of the length of the pick-up arm is a multiple of the lever size of the control mechanism. This state of fact is imposed, on one hand, by the dimensions; discs to be played which determine the length of the arm, and, on the other hand, by considerations of construction and size which determine the dimensions of the base, of the lever of the control mechanism. In addition, the horizontal displacements of the arm are gerrerad controlled by means of an axis of small diameter (vertical pivot axis) on the end of which the arm is articulated along an axis hoTizontal linking its vertical movements. The vertical axis also carries an actuating crank mechanically connected to the control members of the horizontal displacements of the arm. The disadvantageous length ratio existing between the length of the arm, of the pick-up and that of the crank has the consequence that the forces to which this crank and the organs connecting it to its control member are subjected are, much higher@ than those which can be applied fortuitously, inadvertently by the user, on the arm. -of the pick- 11p. 11 follows that the organs: transmission connecting the first arm. to its control organ, horizontal displacements may be subjected to dangerous efforts which may cause their deformation, so that the return of the pick-up above the first groove of a record to be played may not no longer be properly insured. The subject of the present invention is a transmission device mechanically connecting the arm of the pick-up with a talking shoe, provided with an automatic disc loading mechanism, to the displacement control members. of that arm. This device tends to eliminate the drawbacks mentioned by the fact that it comprises an elastic coupling inserted in at least one of the chains of transmission members connecting the arm of the pick-up to its members. control, this aecoupling elastically connecting two members of said chain, so as to absoTber the fortuitous forces undergone according to a direction by the first arm, of the pick-up.

The attached drawing shows, schematically and by way of example, some embodiments of the device which is the subject of the invention.

fig. 1 is a perspective view of a first form of execution of the coupling, ely inserted in the chain of transmission members causing the horizontal displacements of the arm, of the pick-up. fig. 2 is a perspective view of an execution variant.

fig. 3 is a perspective view of a second execution variant.

fig. 4 is a perspective view of a coupling inserted in the ohaine of the transmission organs causing the vertical displacements of the arm of the piek-up.

fig. 5 is a view in longitudinal section by fax of pivoting of the arm of the piek-up and showing another variant of the execution of the coupling. For greater simplicity and clarity of the drawing, only the organs necessary for a good understanding of the device that is the subject of the invention have been represented schematically.

In the form of execution according to FIG. 1, fax 1 represents Faxe pivoting the pick-up arm. Cat axis carries a lever 2 on which is fixed a pin 3. The latter is engaged between two arms 7 and 8 pivoted freely on an axis 4 coaxial with the axis 1. These two arms are connected by a spring 6 tending to maintain them both in contact with the pin 3. The pin 4 is mechanically connected to a control member for the horizontal displacements of the pick-up by members, not shown. This axis 4 carries a lever 5 on which is fixed a lug 9 engages between the arms 7 and B.

The operation of the device described is as follows: In normal operation, the displacements imparted to the axis 4 are transmitted to the axis 1 by means of the elastic coupling constituted. by the two arms 7 and 8 elastically connected and embracing the two lugs 3 and 9. The spring 6 is calculated so as to allow the transmission of a cut sufficient for the actuation of the arm. pick-up, Borte that the respective angular pos ition of the pins, 3 and 9 is exactly defined.

When the arm of the piak-up undergoes a thrust, due for example to a false maneuver by the user; and that this pause causes a torque greater than that necessary for the @control of movements, of the pick-up - forces which could cause the possible deformation of certain organs of the chain of transmission organs connecting the arm, of the pick-up to its control member of its horizontal displacements - the elastic coupling absorbs these. efforts and therefore avoids any deterioration of the mechanism. Indeed, as soon as the first torque exceeds that which the elastic coupling can transmit, the arms 7 and 8 are moved relative to each other against the action of the RTI ID="0002.0276" WI="11" HE= "4" LX="1458" LY="572"> spring 6. As soon as the thrust is inadvertently exerted on the arm of the eesise pick-up, the spring 6 brings the two arms 7 and 8 together with the two lugs 3 and 9 thus automatically restoring the exact relative position of the driven lug 3 with respect to the driving fergot 9.

Dann the execution variant according to fig. 2, the elastic 1'aocouplem-ent es: t con: s@titue by a spring with two branches 10 whose median part 11 can rotate freely on the end of Faxe 4. The operation of this Variant of execution is in all respects similar to that described with reference to the embodiment of FIG. 1.

In the embodiment according to FIG. 3, the first lever 5 acts directly on the pin 3 and the elastic coupling is constituted by a spring with a single arm 12 fixed on the fax 4. In this form of execution, the elastic coupling cannot absorb that efforts resulting from thrusts exerted in a single direction. Dann certain forms of execution of the mechanism for actuating the arm of the pick-up such protection is sufficient, because said mechanism includes by tga constitution mem-e protection dann 1'autre direction.

The elastic coupling shown in Figs. 4 and 5 is planned for the prote@etion of the chain of organs of transmis- son connecting the arm of the pick-up to Good control organ causing its. vertical movements. It should be noted that in this case - a coupling absorbing the forces resulting from a thrust exerted from top to bottom on the pick-up is entirely sufficient to protect the organs from this mechanism, because in general the - arm of the piek-up rests freely on the end of a pusher causing it to move vertically.

In the embodiment shown in FIG. 4, the pick-up arm rests on the end of a pusher 18. The latter rests on one of the ends of an oscillating lever 7.4 articulated at 15 on a member 16 mechanically connected to a member command (not shown) for the vertical movements of the arm of the pick-up. A spring 6 elastically connects the lever 14 to the organ 16 and tends to maintain them in a relative position at the end of a stop 17 with which part of the lever 14 comes into engagement. Lever 14 itself pivots freely on Page 15.

The operation of this form of execution can be understood without further study from FIG. 4.

Finally, in the alternative embodiment according to FIG. 5, the elastic coupling is constituted by a compression spring 18 arranged between two rods 18a and 13b of the polisher acting without the arm of the pick-up. One of the Parts 13b of this pusher has a practical recess 19 following its longitudinal axis, while the other Part 13a has an extension 20 intended to enter the recess 19.

Choville urn 21 secured to the extension 20 and passing through the walls of the section 13b by an elongated opening 22 fixes the extreme relative positions that the two sections 13a and 13b can occupy with respect to each other. Finally, the first spring 18 is aphlüe by one of its ends on the front face of the trongon 13b and by its other end on a shoulder 23 qwe presents the first trongon 13a. This spring tends to maintain the two sections relative to each other in the position shown.

It is obvious that a thrust exerted from top to bottom on the first arm of the pick-up causes a potLssee acting .d!an.s. 1st same direction on 1st section 13ca of the push, o, ir. If this push- eur- passes 1'effort quo can transmit the first spring 18, the latter compressing ab, absorbs this push and avoids a deterioration of the organs of the mechanism. From what is on hand and from the e.ämen of the dnssin, we see that the device described with reference to the appended schematic drawing makes it possible to effectively protect the 1st pick-up movement control mechanism against damage. - damage (deformation, displacement of organs, etc.) due to accidental thrusts exerted on the pick-up arm by the inadvertent driver.

It is obvious that the elastic coupling described can be provided and constructed in many other ways than those described with reference to the drawing, in particular, all the organs represented can be replaced without other means by their mechanical equivalents. ,.

Claims (4)

_ CLAIM Device limiting the forces acting on the organs, of transmission connecting mka.- only the 1st arm of the pick-up of a speaking machine, provided with a mechanism for automatic change of the discs, aug organs of control of the displacements, of the said arm, characterized by the fact that it comprises an elastic coupling ins, wanders in at least one of the chains of transmission members relating the arm to its control members, this coupling elastically connects two members of the loose chain, so to absorb the fortuitous Bubis forces in at least one direction by the arm of the pick-up. SUB-CLAIMS 1. Device according to claim, characterized by the fact that the arm of the pick-up pivots on a vertical axis carrying a crank constituting the member driven by the elastic coupling, 1 the coach member being constituted by a crank fixed to an axis eoaxial to the pivot axis of the arm. 2. Device according to claim and sub-claim 1, characterized by the fact that one of said coagulated arms carries two levers pivoted freely on it and elastically connected to each other by a spring tending to keep them in permanent contact. with the crankpins of the two cranks carried by the said axles. 3: Device according to claim 41, sub-rev. endicaii:on 1, characterized in that one of the said coaxial axes carries a spring with two branches acting on the crankpins 41e9, two cranks, so as to , maintain them in a defined relative position. 4. Device according to claim, charac- t6risepar -1e fact that the first pick-up ropose on a pusher provo.qüant s@as vertical displacements and constitutes by @two trongons. elastically connected to one another by a spring so that the latter absorbs the thrusts exerted d2 Baut down on the arm of the pick-up.