US2831368A - Arresting mechanisms for use with switches - Google Patents

Description

F. BAUER 1,368

ARRESTING MECHANISMS FOR USE WITH SWITCHES April 22, 1958 Filed Jan. 6, 1953 F/PFM/Z 8/905? 4 160 Win 24 wrap/for ijnited States Patent Q ARRESTING MECHANISMS FOR USE WITH SWITCHES Franz Bauer, Vienna, Austria, assignor to Hubert Naimer, Vienna, Austria Application January 6, 1953, Serial No. 329,861

Claims priority, application Austria January 22, 1952 3 Claims. (Cl. 74-527) The present invention relates to an arresting mechanism for use with rotary switches, that is to say, a mechanism for arresting a rotatable member in at least one predetermined position in relation to a counter member. Arresting mechanisms are commonly used with electric multi-position rotary switches in which it is desired to bring the spindle of the switch, forming the rotatable member, into one of several predetermined positions in relation to the housing of the switch which forms the counter member. A typical example of such a switch is the starting switch of an electric railway engine.

Up to now, arresting mechanisms of this kind have usually been constructed in such a manner that at least one, but usually two rollers, mounted on levers, are pressed through tension springs to engage a disc of arresting points, the said levers being pivoted about points located on a circle about the axis of the switch. This mechanism has the disadvantage that the rollers do not move in a straight line in relation of the axis of the switch, but in an arc. Such movement does not allow a ready counter-play of roller and arresting disc. This disadvantage can be diminished by extension of the length of the lever but this however leads to a mechanism of large dimensions. Furthermore, the tension springs are fastened to the levers by means of loops, the loops being formed by bending a part of the spring spiral through 90 in the direction of the axis of the spring. The loops thus formed are considerably susceptible to breakage, and because of this the spring has to be dimensioned more strongly than would be necessary for arresting the switch. Alternatively, the ends of the springs have to be provided with a special suspension arrangement. According to another proposal, at least one roller acts over a lever component with springs supplying the restoring force, the said springs being secured on the ends of this component. The axis of the roller is guided in slots which run along in the direction of the movement of the roller.

One object of the present invention is to provide an arrangement of the last mentioned kind, which is compact and which, irrespective of its small dimensions, overcomes large arresting forces, without showing any sign of large wear and tear. These advantages are obtained by providing a mechanism in which the play of the roller shaft in the member on which the roller is resting and on which the restoring forces of the springs act is greater in the direction transverse to the direction of movement of the roller, than the play of the roller shaft in the same direction in the slots guiding the said shaft.

Two embodiments of the invention will now be described by way of example with reference to the accompanying drawing in which:

Fig. 1 shows an arrangement in which the rotatable members can be arrested in any one of six predetermined positions the cover of the housing having been removed,

Fig. 2 shows in the upper half a section along line Ila-{Ia and in the lower half a section along a line ilbllb of Fig. 1,

ice

Figs. 3 and 4 are plane and side elevations of a guide member of the mechanism shown in Figs. 1 and 2,

I Fig. 5 serves to illustrate the distribution of forces, according to the invention,

Figs. 6-8 show the second embodiment for twelve predetermined positions and with a permanently fixed arresting member; in detail,

Fig. 6 shows a front view of the mechanism with the cover removed, and

Figs. 7 and 8 are sections through the mechanism along the lines VIIVII respectively VIII-VIII of Fig. 6 the latter section showing only a single component, namely the housing.

In Figs. 1 and 2, 1 is the shaft of an electric switch (not shown) of the kind having a six position switch element.

The shaft 1 forms the rotatable member, and a housing 2 forms the counter-member. An arresting component 3 is fixedly mounted on the shaft 1. So as to distribute the existing forces symmetrically, two rollers 4 are provided, and these rollers rest by means of shafts 5 in two bridge-like components 6 respectively, hereinafter referred to as the roller bearing members. The roller bearing members are well known and in this embodiment consist of two trapezoid sheet-iron parts, which are joined at 6 by two bridges respectively. The two bridges at 6 provide counter-bearings for compression springs 7. Other'forms of the roller bearing members may be employed depending on the material used for the members, the material of course not necessarily having to be a metal, and on the manner of manufacture (punched components, pressure cast components or presscomponents). In Fig. 1, only the centre lines 7' of the two lower compression springs are shown. All the springs havea secondbearing in recesses of the housing 2.

The embodiment so far described acts in such a manner that by turning the arresting member 3, the rollers 4 are moved further away from one another and thereby cause the compression springs 7 to be further compressed. However, at the same time, the springs are turned by forces directed transversely to the spring. The same is true if tension springs are used in place of compression springs. In order to eliminate this the following measures are taken:

The roller shafts 5 protrude in a sideward manner beyond the trapezoid components of the roller bearing members and are guided in slots 9 which may be provided immediately in the housing 2 and in the cover component 2'. In cases where the housing 2 and cover 2 consist of material which has small resistance to wear (for example Silium-pressure cast) said slots are grooved into separate guide members 10, which are then inserted into respective recesses in the components 2, 2, this embodiment being illustrated in Figs. 1, 2. The guide member 10 can be seen clearly in the lower half of the Fig. 1, in which the lower bridge is shown in a dotted line, and in the Figs. 3 and 4. The two guide members 10 may, of course, be formed as one single press-component, which if the occasion arises also provides the spring counter-bearings.

This arrangement leads to a most advantageous distribution of the existing forces, which are now explained with reference to Fig. 5, in which like components bear the same reference numerals as those in Fig. 1.

In Fig. 5, the roller shaft 5 carrying the roller 4 is rotatably mounted in the member 6, bearing advantageously with a certain amount of side-play. The member .6 is shown in section showing the two bridges 6', forming the bearings for the springs. The springs are represented by the forces A produced by them. If the arresting member 3 of Fig. 1 is turned in a clock-wise direction, it exerts a force on the roller 4 approximately in the direction P. This force is split up into an upward directed component force P, and a horizontal component force P", the component force F effecting the lifting of the roller bearing member 6 against the forces A, and the component force P" being taken up by the member 10, or more precisely by the slots 9 thereof. This distribution of forces is improved if the shaft 5 is mounted in the bearing member 6 with a certain amount of play, because the slot 9 can then transform the forces acting on the shaft 5 only in the direction of the component force P on to member 6, provided, of course, that the guiding by the slots 9 is sufiiciently accurate, in which case the shaft 5 will not touch the side of the bearing in the member 6, the said shaft being suspended therein. The member 6 may be rotatable about the shaft 5 so that if the two forces A are not exactly the same, as may be the case in practice, the member 6 can take up a slant position during the lifting thereof until a position is reached where moments of the forces A are equal in relation to the shaft 5.

The operation is the same for the lower roller bearing member 6 but it can be seen that this is not essential. Symmetry of the forces acting in the mechanism is, however, an advantage. Furthermore it is evident, that instead of two springs for each roller bearing member 6, only one need be used, this being located symmetrically with respect to member 6. Alternatively, tension springs may be used instead of compression springs.

The Figs. 6-8 show a second embodiment of the invention in which a large number of predetermined arrestin positions (twelve in Fig. 6) are obtained. The example according to Figs. 6*8 use for this purpose a stationary arresting member 15 with arresting points facing inwardly. The member 15 is then the counter member. The rotatable member is the spindle 16 which belongs to a switch. On the spindle 16 are fixed two guide members 17 rigidly mounted on the spindle 16 for turning movement. The members 16 are provided with slots 18 which carry the shafts 19 of rollers 20. The shafts 19 rest in roller bearing members 21 in the hereinbefore described manner, the roller bearing members acting at their ends on compression springs 22. For clarity the parts 17, 20 and 21 in Fig. 6 are partly omitted, the parts not omitted being shown by dotted lines. The manner of action is as follows:

When the spindle 16 is turned, the members 17 make the same turn. The shafts 19 are thereby moved inwards, as the rollers 20 travel over the crests between neighbouring arresting grooves, and the springs 22 become compressed by roller bearing members 21. After overcoming the inner dead point of the roller movement in relation to the shaft 16, as in the first embodiment shown in Figs. 1 and 2, the roller will under easing of the springs fall into the next arresting groove. The distribution of the forces is the same as that already described. The forces shown by the arrows are for a clock-wise rotation of the shaft 16.

The distribution of forces described has proved to be the most advantageous in so far as reduction in the wear and tear of the components, and their rolling and sliding on one another. The length of life of a mechanism according to the invention is for this reason much greater than that of known mechanisms, which are as large or even larger.

The embodiment shown in Fig. 6 is not a cinematographic inversion of the embodiment shown in Fig. 1, not even if one disregards the dilferent number of arresting positions and other structural diiferences. The cinematographic inversion of the embodiment shown in Figs. 1 and 2, would be such that the shaft 1 is held stationary and the housing 2 rotatable. The components should then follow the turning movement of the housing, whereas the guiding components 17 of the embodiment shown in'Figs. 6 and 7 follow the turning movement of the shaft, and the housing is held stationary.

Fig. 8 shows a section through the housing 15 which carries the arresting grooves on a ring 25, but it is to be understood that this manner of construction is not essential. The bearing of the shafts 1 and 16 in the housing 2 and cover 2, and in the housing 15 and cover 15 respectively is not shown in detail, but is, of course to be provided.

The invention permits numerous constructive forms of the mechanism. The number of springs which are to be put under tension per switching movement can be chosen to be difierent from the number shown. The roller bearing members carrying the rollers need not be set at 180 to one another, which of course is not possible when an odd number of predetermined positions is required. The rollers and their shafts may consist of a single member, if this arrangement is preferred and if necessary roller bearings may be used. In the embodiment shown in Figs. 6 and 7 a second pair of roller bearing members may be provided, these members being displaced in relation to the other pair through so as to bring about, in a small space, large arresting forces. The combination of compression springs and tension springs is also pos sible. It is to be understood that the expression springs may include, for example, rubber bufiers.

Finally it is to be understood that uses other than with electric switches are possible. For example, another application is in the fixing of a regulatng lever in one of several predetermined positions.

What I claim is:

1. A holdingmechanism for holding a rotatable member in at least one predetermined position in relation to a stationary member, comprising, in combination: a cam operatively connected with said rotatable member and having a toothed periphery, at least one roller engaging said periphery and being movable by the rotation thereof, a roller bearing yoke having two ends, means for mounting the roller centrally on the yoke with a clearance in a direction transverse to the direction of movement of the roller, a pair of compression springs acting upon the ends of the yoke with a force opposing the force of movement of the roller engaged by the rotating cam periphery, and radial guide means for guiding the roller substantially without transverse play in the direction of its movement.

2. The arresting mechanism as defined in claim 1, wherein said radially slotted guide means is a guide member fixedly connected to the stationary member.

3. A holding mechanism for holding a rotatable member in at least one predetermined position in relation to a stationary member, comprising, in combination, acam fixedly mounted on the rotatable member and having a toothed periphery, at least one roller engaging said periphery and being movable by the rotation thereof, a roller bearing yoke having a central slot arranged transversely 'to the direction of movement of the roller the roller being trunnioned in said slot, a pair of compression springs acting upon the yoke with a force opposing the force of movement of the roller engaged by the rotating cam periphery, and a guide member having a radial slot for guiding the roller in the direction of its movement substantially without transverse play.

References Cited in the file of this patent UNITED STATES PATENTS 1,038,567 Greenguard Sept. 17, 1912 1,896,850 Perry Feb. 7, 1933 2,115,284 Pratt Apr. 26, 1938 2,130,219 Allison et al. Sept. 13, 1938 2,409,656 Austin Oct. 22, 1946 2,579,169 Barry Dec. 18, 1951 2,639,338 ,Kwasniewski May 19, 1953

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