Magnetically Coupled Control For Cooking Platform

Abstract

A magnetically coupled type of control for a cooking platform has a movable support member for the magnetic follower in which the support member has a rack gear on one side for engagement with a rotatable pinion gear on a shaft of the thermal cycling switch, and with the other side of the support member having a channel receiving the straight portion of a guide bar and a pair of opposite open-ended slots to accommodate the ends of the guide bar in the rectilinear movement of the support member, with the secured ends of the guide bar serving as opposite end limits to movement of the support member.

Description

BACKGROUND OF THE INVENTION

1. Field of the Invention

This invention pertains particularly to magnetically coupled controls useful with counter-top cooking platforms.

2. Description of the Prior Art

The closest prior art of which we are aware is U.S. Pat. No. 3,711,672 in which a rack gear positioned between two pinion gears moves with the magnetic follower, with the two pinion gears controlling a potentiometer and an on/off switch in accordance with their rotation. The arrangement of the subject invention is considered an improvement thereover in several respects including that of reduced cost and being adapted to use a thermal cycling switch and a return spring arrangement. The subject arrangement is also adapted for use on either the right or left end control panel areas with the follower member being adapted to be positioned in either one or another laterally separated locations during assembly of the control to accommodate either a right or left-hand side arrangement.

SUMMARY OF THE INVENTION

In accordance with our invention, the magnetically coupled control includes a user-operated control member on the accessible side of a control panel, a magnetic follower member on the other side of the panel, a support plate adapted to support two individual controls, an energization controller mounted to the support plate and having a rotatable shaft carrying a pinion gear, a guide bar mounted at its ends to the plate and having a straight length portion extending in both directions beyond the pinion gear, a support member for the follower including a rack gear on one side for engagement with the pinion gear and having an oppositely disposed channel-shaped section receiving the straight length of the guide bar and a pair of opposite, open-ended slots accommodating the ends of the guide bar in the rectilinear movement of the support member, with the guide bar ends serving as opposite end limits to movement of the support member, and means for mounting the follower member on the support member to constrain movement of one relative to the other in a plane parallel to said support plate while permitting relative movement in a direction perpendicular to that plane.

DRAWING DESCRIPTION

FIG. 1 is a partly broken plan view of a cooking platform provided with a control arrangement according to the invention;

FIG. 2 is a side elevational view, partly broken and sectioned of a control arrangement according to the invention, with the support and follower member being shown in one extreme position in solid lines, and in an opposite extreme position in broken lines; and

FIG. 3 is an exploded isometric view, partly broken and sectioned, to illustrate details of the arrangement.

DESCRIPTION OF THE PREFERRED EMBODIMENT

As shown in FIG. 1, the cooking platform as viewed from above essentially comprises a generally perimetric frame 10 of relatively thin, substantially non-magnetic material such as aluminum or a 300 series stainless steel, with a glass ceramic plate 12 occupying a central opening of the frame and provided with visual indicia 14 for indicating the cooking areas and underlying locations of the heat producing elements 16. The user-operated control member 18 for each cooking area is located in a control area 20 of the control panel at the right and left-hand sides of the frame 10.

An individual control system is provided for each of the cooking areas. Each control system includes the control member 18 on the upper or accessible side of the control panel, a follower member 22 on the under or other side of the control panel, a support member generally designated 24 upon which the follower member carriage 22 is seated, a guide bar generally designated 26 secured at its opposite ends to a support plate 28, and an energization controller such as a thermal cycling switch mounted to the plate and having a pinion gear 30 on the upwardly projecting shaft of the thermal cycling switch.

As may be best seen in FIG. 1, a single support plate 28 is provided for each of the control panels at the right and left-hand sides of the frame, and two individual control assemblies are associated with each of the support plates. The support plate is provided with slotted holes 36 at those locations at which the plate is secured to a supporting box 34 (FIG. 2). This permits the support plate to be shifted longitudinally before securement to obtain correspondence between the control energization level indicia 37 on the control panel and the position of the underlying control mechanism. It will also be noticed from FIG. 1 that the support plate 28 and the individual control assemblies are not in mirror image relationship to each other on the right and left-hand sides, but rather that any given support plate with the control assemblies may be used on either the right or left-hand side without turning them end for end. This is possible with the arrangement according to the invention because the follower member 22 may be shifted laterally on the support member to either of two alternate positions, as will be further explained later.

Referring to FIGS. 2 and 3, the control member 18 and the follower member 22 may be of the same general structure and have magnetic blocks therein as described in the noted U.S. Pat. No. 3,711,672. As there taught, as the control member is moved along the control panel 20 in the direction indicated by the arrows in FIG. 3, the follower member 22 will correspondingly be moved in the same direction with the wheels 32 of the carriage of the follower member riding against the underface of the panel.

The support member 24, upon which the follower member seats, is formed of two separate plastic parts, an upper part 38 and a lower part 40 which are coextensive in length. The upper part includes a block 42 with two pairs of bores formed therein, with the one pair 44 being laterally offset from the other pair 46. As seen in FIG. 3, a pair of downwardly projecting posts or bosses 48 on the underside of the follower member 22 are adapted to be received in either one or the other pairs of the bores, depending upon whether the control assemblies are at the right-hand or the left-hand side of the cook top. In either case, the posts are received in those bores which are toward the outer side of the cook top. Thus, in FIG. 3, the posts are received in the bores 46 indicating that this is the left side of the cook top. The posts are loosely received in the bores so that, while the follower may move upwardly relative to the block 42, lateral movement of the follower relative to the block 42 is not permitted. This arrangement permits the carriage to move up solidly against the underside of the control panel when the control member 18 is in place.

Both the upper and lower parts 38 and 40 of the support member are molded acetal plastic parts to provide low friction contact surfaces. The lower part 40 includes a rack gear 50 along one side and includes a base flange 52 on its other side provided with two opposite, open-ended slots 54 with an intermediate web or land 56. These opposite, open-ended slots in the base flange portion of the support member accommodate the right angle end portions 58 of the guide bar 26 during the rectilinear movement of the support member from one extreme position to the other, with the end portions serving as stops for the support member when the land 56 abuts the end portions 58 of the guide bar.

The underface of the top part 38 of the support member is provided with a downwardly open channel which seats upon the top face of the lower part 40 of the support member in the assembled relation of these parts. These parts 38 and 40 are held together in their assembled relation by the screws 60 and nuts 62.

With the upper and lower parts 38 and 40 of the support member assembled, the straight length portion 26 of the guide bar is in effect captured in the channel-shaped space 64 on the one side of the support member, with the other side of the support member being held in position by the engagement of the pinion gear 30 with the rack gear 50.

The thermal cycling switch 66 may be of the general type shown in either U.S. Pat. No. 2,813,173 or 3,634,802, these being conventional switches for controlling energization of heating elements and are sometimes referred to as infinite switches. The upwardly projecting D-shaped shaft 68 of the infinite switch receives the pinion gear 30 thereon and a spiral return spring 70 is provided with one end attached to the pinion gear and the other end attached to the support plate 28. Thus, as the pinion gear is rotated in the direction of the arrow in FIG. 3 by the movement of the support member 24, the return bias of the spring 70 is increased. However, the return force of the spring is not sufficient to overcome the friction between the control member 18 and the top panel created by the magnetic attraction between the control member and the follower member. However, if the control member 18 is removed from the control panel, the return spring will rotate the pinion gear and infinite switch shaft in a clockwise position, forcing the support member 24 back to the extreme position shown in FIG. 3. This, of course, corresponds to the infinite switch being in an Off position and deenergization of the heating element.

The arrangement as described results in a relatively low friction load so that, if the magnetic coupling is broken by removing the control member 18, the parts will return to the Off position. The low friction load exists because the guide bar 26 offers relatively little resistance to movement of the support member 24, and the fit of the support member to the guide bar and the pinion gear 30 is relatively loose. Also, the thermal cycling switch has a relatively low internal friction as contrasted to a potentiometer.

The relatively loose seating of the carriage on the support member permits the carriage to rise slightly in its magnetically coupled relation to the control member to compensate for manufacturing tolerances in the vertical spacing between the support plate and the control panel.

In the assembly of the parts, the thermal cycling switch 66 is oriented to an Off position by the location of the flat on the D-shaped shaft and with the spring 70 in a preloaded condition before the rack gear 50 of the support member 24 is engaged with the gear 30. With one end of the guide bar 26 loosened, the support member 24 is moved to the extreme position at which the land 56 abuts the other end 58 of the guide bar as shown in FIG. 3, and the support member is then swung to place the rack gear into engagement with the pinion gear. Then, the loose end of the guide bar is moved over and secured to hold the engagement between the rack gear and the pinion gear. The slotted holes 36 in the support plate 28 permit the final adjustment of the support plate 28 to be made to provide the proper registry between the switch Off postion and the position of the control member 18 on the control panel 20.

The arrangement, which permits the shifting of the carriage 22 laterally to either the one pair of bores 44 or the other pair 46, accommodates the lateral registry of the control assembly with the control member 18 at either side. This is considered advantageous in connection with proposed standards which require a minimum distance from the edge of any heating element to the location of any control element.

Claims

We claim:

1. In a magnetically coupled type of control arrangement for a cooking platform having a heat producing element:

a user-operated control member on the accessible side of a control panel;

a follower member on the other side of said panel adapted to be magnetically coupled to said control member;

a support plate spaced from said other side of said panel;

a controller for controlling energization of said heat producing element mounted to said support plate and including a rotatable shaft projecting therefrom and having a pinion gear fixed thereon;

a guide bar mounted at its ends on said plate and having a straight length extending on both directions beyond said gear; and

a support member for said follower member having a gear rack on one side for engagement with said pinion gear, and provided with a pair of opposite, open-ended slots on the opposite side to accommodate the ends of said guide bar in the rectilinear movement of said support member, said guide bar ends serving as opposite end limits to movement of said support member.

2. In an arrangement according to claim 1 including:

means for mounting said follower member on said support member to constrain movement of one relative to the other in a plane parallel to said support plate while permitting relative movement in a direction perpendicular to said plane.

3. In an arrangement according to claim 1 including:

means biasing said pinion gear and controller to a deenergized position.

4. In an arrangement according to claim 1 wherein:

said support plate includes slot means for securing said support plate in one of a number of longitudinally shifted positions to facilitate proper registry of said control member with indicia on said control panel.

5. In an arrangement according to claim 2 wherein:

said means for mounting said follower member on said support member includes a pair of projecting posts on said follower member and two pairs of post receiving bores on said support member, one pair of said post receiving bores being laterally offset from the other pair to permit alternative positioning of said follower member relative to said support member.