FOR DRIVING A ROTARY CABLE

Related Applications

This application claims priority to U.S. Provisional Application No. 81/975,062, filed April 4, 2014, the entirety of which is incorporated herein by reference.

Field of the Invention

The present invention is directed to a rotary knob assembly and is particularly directed to a rotary knob assembly for driving a rotary cable at a selected output angle.

Background

A rotary knob assembly for controlling an end use device is known in the art. In vehicle heating, ventilating, and air conditioning ("HVAC") systems, rotary knobs are often used to control an end use device that is part of the HVAC system. The end use device is connected to the rotary knob via a rotary cable. The rotary knob is mounted in a HVAC control housing. The rotary cable can enter the control housing at different angles depending on the end use device being controlled and the particular vehicle platform. Known arrangements have required complex gearing arrangements to connect the rotary knob to the output cable. Each knob/cable angle difference has required a different knob/gear design arrangement to accomplish the cable connection.

Summary of the Invention

The present invention provides a rotary knob assembly for connecting to a rotary cable that permits any one of a plurality of selected cable entry angles.

In accordance with one example embodiment of the present invention, a rotary knob assembly includes a housing having a front cover and a back cover. A pinion shaft is mounted to the housing between the front cover and the back cover so as to rotate about a first axis. The pinion shaft includes a pinion gear. An output gear assembly is mounted to the back cover and has an angle of rotation at any one of a plurality of predetermined angles relative to the first axis. The output gear assembly includes a helical gear in meshing engagement with the pinion gear so that rotation of the pinion gear rotates the helical gear. A rotary drive cable is attached to the output gear so that rotation of the helical gear rotates the rotary drive cable.

In accordance with another example embodiment of the present invention a rotary knob assembly Is provided comprising a housing having a front cover and a back cover and a pinion shaft mounted to the housing between the front cover and the back cover so as to rotate about a first axis, the pinion shaft including a drive gear. An output gear assembly is mounted to the back cover and has an angle of rotation at a selected one of a plurality of predetermined angles relative to the first axis. The output gear assembly includes a driven gear in meshing engagement with the pinion drive gear so that rotation of the pinion shaft rotates the driven gear of the output gear assembly. The drive gear and the driven gear are adapted so as to allow the angle of rotation of the output gear assembly to be at any one of a plurality of predetermined angles relative to the first axis. A rotary drive cable is attached to the output gear so thai rotation of the driven gear rotates the rotary drive cable.

Brief Description of the Drawings

The foregoing and other features and advantages of the present invention will become apparent to those skilled in the art to which the present Invention relates upon reading the following description with reference to the accompanying drawings, in which;

Fig. 1 is a perspective view of an HVAC control box housing having a rotary knob assembly in accordance with one example embodiment of the present invention;

Fig. 2 is another perspective view of the HVAC control box housing of Fig. 1 ; and

Fig. 3 is a top plan view of the HVAC control box housing of Fig. 1. Referring to Figs. 1-3, a rotary knob assembly 20, in accordance with one example embodiment of the present invention, is shown. By way of example, the rotary knob assembly 20 is described for use in a vehicle HVAC system but couid be used for other purposes and/or other systems.

The rotary knob assembly 20 is mounted in a control panel housing 26 such as a housing used to control the vehicle HVAC system. Shown in the Figures is a control panel housing 26 having three rotary knob assemblies 30, 32, 34 mounted therein. Each of the three rotary knob assemblies 30, 32, 34 has similar parts. For the purposes of brevity and clarity, only one of the rotary knob assemblies 30 is described in detail.

The rotary knob assembly 30 includes a pinion shaft 40 roiaiably mounted between a front cover plate 44 and a back cover plate 48 of the control panel housing 26 so as to rotate about; a center axis 50 of the pinion shaft 40. One end of the pinion shaft 40 receives a rotary knob 54 secured to the end of the pinion shaft 40 by press fitting, spline connection, set screw, or other means. The pinion shaft is axially fixed relative to the front cover plate 44 and the back cover plate 46.

The pinion shaft 40 includes a straight cut gear 60 integrally formed on the pinion shaft 40. The pinion shaft 40 further includes a detent profile 64 that is used to provide haptic feedback to rotation of the knob 54. A ball and spring unit 66 is secured to the front cover 44 and aligned with the detent profile 64. As the pinion shaft 40 rotates, the ball and spring arrangement biases the ball into valleys of the detent profile 64 to provide the haptic feedback such as a lock and release feel during incremental knob rotation.

The rotary knob assembly 30 further includes a rotary output gear assembly 70 that is mounted in the back cover 48. The output gear assembly 70 includes a helical gear 74 that is in meshing engagement with the pinion shaft gear 60. When the knob 54 is rotated, which in turn, rotates the pinion shaft 40 and gear 60, the helical gear 74 rotates. In accordance with one example embodiment of the present invention, the gear ratios between gear 80 and helical gear 74 is two to one so that one complete turn of the pinion shaft 40 rotates the helical gear 74 two times.

The rotary output gear assembly 70 has a rotary output axis 78 that is angled a relative to the rotary axis 50 of the pinion shaft 40. A rotary cable 82 is operative iy connected to the output gear assembly 70 so that when the helical gear 74 is rotated, the cable 82 rotates. The cable 82 is connected to the output gear assembly 70 via a spline connection,

The present invention permits the angle a between the pinion shaft axis 50 and the output gear assembly axis 78 to be a wide range of values without any change in the rotary knob assembly design. For example, the rotary knob assembly 30 shown in the Figs. , the angle a is approximately 20°. The rotary knob assembly 32 shown in the Figs, has an angle a approximately equal to 0° between its pinion shaft axis and the axis of its associated output cable. The rotary knob assembly 34 shown in the Figs, has yet another different angle a between its pinion shaft axis and its associated output cable axis. Therefore, it should be appreciated that the present design permits the same rotary knob assembly design to have a variety of cable output angles relative to the pinion shaft axis without any need to change the design of the assembly elements.

The back cover 46 has output gear mounting surfaces angled at angles commensurate with the entry angle of the output cable entering the control panel housing 26 depending on the location of the end use device that the output cables are connected to for ultimate control.

From the above description of the invention, those skilled in the art will perceive improvements, changes and modifications. For example, it is contemplated that the helical/straight cut gear arrangement between the two parts could be reversed from that described. In effect, the helical gear 74 could be replaced with a straight cut gear and the straight cut gear 80 could be replaced with a helical gear. In such an arrangement, the pinion shaft carries the helical gear and the output, gear assembly carries a straight cut gear. Also, both gears could be beveled gears or a

combination of helical/bevel gears. Also, other shaped gears could be used that provide for a variable angle mounting arrangement between the pinion shaft and the output gear assembly. Such improvements, changes and modifications within the skill of the art are intended to be covered by the appended claims.