US2257098A - Transmission mechanism - Google Patents

Description

Sept. 30, 1941. C, A

ARENS- TRANSMISS ION MECHANI SM Filed Dec. 19, 1958 mgnunnuuu' llllln.y

ATTORNEYS:

Patented Sept. 30, 1941 UNITED STATS PATENT OFFICE TRANSMISSION MECHANISM Charles A. Arens, Chicago, Ill.` Application December 19, 1938, Serial No. 246,546

(Cl. 74-501l 9 Claims.

This invention relates'to transmission mechanisms, and particularly to transmission cables for use therewith of the type adapted to 'transmit longitudinal or rotary motion between a control knob or handle and a device to be controlled thereby.

It is an object to provide a transmission mechanism including a transmission cable of improved and economical construction, and of improved operating characteristics.

More specically it is aniobject of the invention to provide a transmission cable construction in which there is contact between the stationary and movable cable parts at only predetermined spaced points longitudinally whereby to reduce frictional resistance in the cable; the parts being so' proportioned and arranged that elective guiding surfaces are provided to enable the construction to be self-cleaning, jamming or locking of the movable parts due to dirt, ice or other foreignv matter, being precluded. The friction between the parts may be so materially reduced that no sticking will occur even when the cable is used dry and in long lengths.

A further object of the invention is to provide a cable construction of the above type which may be eiectivel'y used to transmit rotary motion.

A still further object is to provide a. cable construction as above having at least two relatively -movable elements, in addition to the stationary or housing element, said movable elements being used to transmit either rotary or longitudinal motion, or both.

Other objects are to provide a cable construction of the above type in which the cable struclture may be used to-provide predetermined stop points for the control knob; to provide a cable construction of increased exibility at predetermined points; and to provide a cable which may be eiectively employed as a transmission mechanism for insulated electrical use.

Still other objects and advantages of the invention will appear from the following speciiication when taken in connection with the accompanylng drawing wherein certain preferred embodiments of the invention, are illustrated.

In the drawing, wherein like reference numerals refer to like parts throughout:

Fig. 1 is a general assembly view of a transmission mechanism employing a cable construction made in accordance with one form of the invention.

Fig. 2 is a detail sectional view of the vconstruction shown in Fig. 1, on the line 2-2 thereof.

Fig. 3 illustrates a construction similar to that control board of a 'vehicle or aircraft. The in- Fig. 6, but having -a central core member par ticularly adapted for rotary movement.

This application is a. continuation-in-part of my copending applications Serial No. 83,668, led June 5, 1936, now issued as Patent No. 2,195,400, dated April 2, 1940, and Serial No. 218,814, filed July 12, 1938, now issued as Patent No. 2,146,412, dated February '7, 1939,

Referring iirst to Figs. 1 and 2 of the drawing, the'transmission mechanism illustrated comprises a control handle or knob I0 adapted for manual actuation, and a transmission cable generally indicated by the reference numeral Il for connecting the control handle to the device to be controlled, inthis instance shown as a lever I2 adapted to be pivoted about a shaft III.` 'I'he control knob I 0, which in this instance is adapted for push and pull movement, is reciprocable within a. sleeve I4 mounted in a xed' frame or support member I5 which may, for example, be the ner end of the sleeve I4 is threaded as indicated at I6, a nut I'I being provided on the sleeve threaded portion for holding the sleeve firmly within the support I5.

The transmission cable comprises a sheath I8 and a central core member I9, the core, which may be a wire rod, being secured at one end to the control knob by means of screws Il, and at its other en`d to the lever I2 by means of a clamp device 2|. The rod I9 is of suiicient size so that it will transmit the necessary forces between the control knob I0 and the lever I2 without buckling, and still have suicient iiexibility so that it can be ilexed within predetermined limits. The sheath I8 has the same degree of flexibility, thus permitting the transmission cable'to be bent slightly as may be necessary to avoid obstructions or change the direction of the transmission movement, as is usual in Bowden wire constructions,

, The sheath i 8 comprises a helically wound wire coil, the convolutions of the coil being of progressively increasing and decreasing size whereby to produce a series of spaced portions 23 adapted to have bearing engagement with the reciprocable coreV member, and a series of intermediately disposed larger portions 24 which are spaced from .the core. The convolutions are in tight engage ment with each other, and the larger convolutions 24 are only slightly greater in diameter than the smaller convolutions 23, the difference in diameter between the largest and smallest confvolutions being somewhat less than the thickness or gauge of the wire of the sheath in the particular embodiment shown. The sheath is anchored at one end to the sleeve I4 by any suitable means, such for example as soldering or the like, as in- .dicated at 25, and at the other end to a bracket or the like 26 carried by the housing 2f!` of the controlled device. Referring particularly"f to Fig. 2, it will be seen that the core'member or wire rod I9 is provided with bent or deformed portionsv 28,

29 and 30 which cooperate with'tlie contracted bearing portions 23 of the sheath, acting as stops or positioning means for` the control knob. In operation the control knob I8 ,may be reciprocated manually, this causes the core wire I9 to be reciprocated within the sheath I8, causing the movement of the controlled lever I2 in proportion t0 the movements impartedv to the manually operated knob'.- ABy limiting the areas of con-v tact between the core member and the sheath to the contracted or neck portions 23, which are at spaced points along the sheath, the frictional resistance to movement between the parts is very materially reduced. The tight engagement between the convolutions of the sheath coil prevents dirt from working into the cable, and also prevents grease or other lubricant which may be placed within the spacedpockets 32 from working out. Also the tight engagement of the sheath convolutions renders the sheath incompressible so that no compression or extension of the sheath coil can take place during movement of the core. Limited bending of the sheath, however, is not precluded. The contacting convolutions of the sheath coil, progressively increasing in size very slightly as they recede from the spaced bearing points 23, thereby form effective scraping and guiding surfaces for directing dirt, ice, or other foreign matter which may find its Way into the cable, away fromv the bearing portions 23.and into the spaces 32 which act as reservoirs for the reception V`of such material. The construction is thus rendered self-cleaning and reliable in operation. Control mechanisms of this type are frequently used under service lconditions,.such as in aircraft, where they be subjected to rapid temperature changes including freezing conditions. Condensation and ice formation Within the coil may occur. Also v dirt may find its way into the cablel regardless of precautions taken. The structure of the present invention provides` for the effective removal of such foreign matter from the pointsof rbearing contact. The construction is reliable in operation-and will not stick even when used in long lengths and Without any lubrication whatsoever.

The bent or deformed portions 28, 29 and 30, which may be arranged in any desired position upon theA core I9. act I.as stopsY or positioning In operation, for

means for the control knob. example as the core member is moved to the right as seen in FigA 2, the bend 28 will strike the' contracted neck of the sheath, acting as a stop imparts a uniform cylindrical exterior contour or positioning means. The wire of the core may l be only slightly deformed at the bend, so that the deformed portion can be forced through the contracted sheath neck upon the application of increased pressure upon the control knob,`the A bend acting as .only a temporary or positioning stop; or the bend may be of greater magnitude In Fig. 3 an embodiment of the invention is' illustratedv which is generally similar to that previously described, except that the contracted or neck portions of the sheath coil are of increased flexibility and the sheatlf,` is itself encased in a exible casing. In this instance the wire coil I8 which forms a sheath forthe core Wire I9, as in the previously described embodiment, is of varying gauge and pitch, as Well as of varying diameter. The convolutions 24 Which are of maximum diameter are also of maximum gauge or thickness and are in contacting relation, whereas the neck or bearing convolutions 23 are of reduced gauge or thickness,these convolutions also being separated or spacedV a small amount. The gauge of the convolutions 23 may be reduced as the coil is formed by drawing out thek wire at these portions. The entire coil is` encased in a casing 35 whichmay b e of rubber or installation desired. 'Ihe neck portions 23, having spaced convolutions of decreased wire thickness, increase the fiexibility of the sheath coil I8, and this form of construction rmay be desired for'certain installations. The casing 3 5 prevents dirt from Working into the coil. The casing also to the cable construction. The casing 35 may be of molded rubber, and to prevent the rubber fromy Working into the coil convolutions during formation, the coil may rst be wrapped or encased in a suitable cover 34 of canvas or the like.

In Fig. 4 an embodiment of the invention is illustrated which is particularly adapted for use in insulated electrical installations. In this instance the core Wire I9 may, for example, be a retractable aerial wire 'for aircraft use, movable through the sheath I8. The Wire in such installation would be preferably stranded rather than solid, as in the previously described embodiments, and the sheath I8 would be composed of rubber wire 36 or other insulating .material suitable for working into Wire form. I

Fig. 5 illustrates an embodiment incorporating a rotary central core member. In this form of construction the wire coil/I8 secured at its end to thesupport or frame' I5 may be of the form previously described in, connectionwith Figs. lY

and 2. The core construction I9, however, in this instance is of composite construction, and comprises an inner or base wire 31, a first helically wound wire coil 38 embracing the Wire 31, and a second helically wound wire coil 39 embracing the wire coil 38, the coil 39 being reversely wound with respect to the coil 38. The wire 3`Ifand the coils 38 and 39 are all secured together for movement as a rotary unit. A gear -wheel 40 secured to the outerwire coil by means of aset screw or the like 6i is adapted to be driven by a gear train or other suitable means 42.

in operation as the gear wheel 40 is rotated by its driving mechanism, the core I9 will berotated as a unit within the sheath i8. The coil 38 is adapted to resist rotative forces in one direction of rotation, whereas the reversely wound coil 39 will resist rotative forces in the opposite direction. Accordingly the core construction may be driven by its gear wheel 40 in either or both directions of rotation.

In Fig. an embodiment is illustrated wherein two relatively movable control parts, in addition tov an outer housing sheath, are provided. En

this" form of construction a housing sheath is secured to the support l by means of a set screw' i6 or the vlike. This housing sheath may be a helically wound coil of square wire adapted to form a dirt-tight sheath of limited iiexibility for the cable construction. The wire coil it having convolutions of increasing and decreasing size, as previously described, is adapted for sliding and rotatable movement, or both, within the sheath 45, under control of a manually operable ,knob 4l. The end of the coil i8 may be secured to the knob il by any suitable means, such as by soldering as indicated at 48. The core wire I9 is reciprocable or rotatable, or both, within the coil I8, under control of the control knob iE. This form of constriiction provides two independently reciprocable and/o1* rotatablemembers, core i9 and coil I8, movable within a stationary sheath i5. The construction of coil I8 which is interposed between the core wire 9 and the sheath 45 is such as to impart minimum frictional resistance both to the movement of the coil IB and tc the movement oi the core wire.

In Fig. 7 an embodiment is illustrated which is the same as that shown in Fig. 6, except that the central core construction i9 is of composite construction and is adapted for heavy duty rotary movement, as in the embodiment described in connection with Fig. 5. While a single wire core, as shown in Fig. 6, may be used to transmit rotary as well as push and pull movements, a composite form of construction, as shown in Fig. 7, may be preferred for certain types of installations.

Each of the various modied forms of construction described in connection with Figs. 3 toI l inclusive operates the same as the embodiment shown and described in connection with Figs. l and 2 in so far as the reduced friction, nonsticking, and self-cleaning characteristics of the construction are concerned, and further specic description of the operation of these modified forms of construction is believed to be unnec- CSSaly.

It is obvious that various changes may be made in the specific embodiments shown without departing from the spirit of the invention. The invention is therefore not to be limited to the specific structural embodiments illustrated, but only as indicated in the following claims.

The invention is hereby claimed as follows:

i. A transmission cable for control mecha nisms and the like comprising a sheath, sheath being composed of a wire coil having jacent convolutions or different diameter, and a core member movable within said sheath in contact with the convolutions of smaller diameter, said core member having means formed thereon adapted to engage said smaller diameter convolutions whereby to serve as' a stop or positioning means for the core member.

2. A transmission cable as defined in claim 1 wherein` said stop means may be forced through said smaller diameter convolutions upon the application oi increased force to the core member.

3. A transmission cable for control mechanisms and 'the like comprising a housing, a wire coil movable within said housing, said coil having adjacent lconvolutions of diierent diameter, and a core membermovable within said coil.

fi. A transmission cable as defined in claim 3 wherein said core member comprises a central base wire and at least two wire coils concentrically arranged thereon, said last named coils being relatively reversely wound.

5. A transmission cable for control mechanisms and the like comprising a sheath, said sheath being composed of a wire coil having convolutions of progressively increasing and decreas-v ing radius whereby to produce a series oi longitudinally spaced neck portions of reduced radius, and a core member movable within said sheath `in bearing engagement with said neck portions,

the coil convolutions being in contact and the difference in radius between the coil convolutions of maximum and minimum size being not substantially greater than the thickness of the wire.

6. A transmission cable for control mechanism's and the like comprising' a sheath, said sheath being composed of a wire coil having convolutions of progressively increasing and decreasing radius whereby to produce a series of longitudinally'spaced neck portions of reduced radius', a core member movable within said sheath in .bearing engagement with said neck portions, the

convolutions being in contact and the difference in radius between the coil convolutions yof maximum and minimum size being not substantially greater than the thickness of the wire, and a second sheath of substantially cylindrical exteror contour encompassing the first named sheath.

7. A transmission cable as defined in claim 6 wherein the second sheath and the rst sheath are relatively movable.

8. A transmission cable as dened in claim 5 wherein the core member is rotatablewithin the sheath and comprises a spirally wound wire coil.

9. A transmission cable as definedin claim 5 wherein the core member is rotatable Within the sheath and comprises two oppositely wound spiral wire coils.

CHARLES A. ARENS.

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