Patents by Inventor David T. Llewellyn
David T. Llewellyn has filed for patents to protect the following inventions. This listing includes patent applications that are pending as well as patents that have already been granted by the United States Patent and Trademark Office (USPTO).
-
Patent number: 5310970Abstract: A pressure operated switch construction and method of making the same are provided, the pressure operated switch construction comprising a housing having an external surface and carrying an electrical switch unit and a diaphragm assembly therein, the housing having an opening passing through the external surface thereof, the switch unit having opposed sides and an opening passing therethrough in alignment with the opening of the housing, and a compression spring unit carried by the housing and being operatively associated with the switch unit and the diaphragm assembly to control the operation thereof in relation to the compression setting of the spring unit, the spring unit comprising a spring retainer operatively interconnected to the switch unit, an actuator carried by the housing and a compression spring having opposed ends respectively bearing against the actuator and the retainer, the retainer having an intermediate part disposed in the opening of the housing and having a surface and a projection extendType: GrantFiled: December 15, 1992Date of Patent: May 10, 1994Assignee: Robertshaw Controls CompanyInventors: William J. Kaigler, Thomas M. Buckshaw, David T. Llewellyn
-
Patent number: 5198632Abstract: A pressure operated switch construction and method of making the same are provided, the pressure operated switch construction comprising a housing having an external surface and carrying an electrical switch unit and a diaphragm assembly therein, the housing having an opening passing through the external surface thereof, the switch unit having opposed sides and an opening passing therethrough in alignment with the opening of the housing, and a compression spring unit carried by the housing and being operatively associated with the switch unit and the diaphragm assembly to control the operation thereof in relation to the compression setting of the spring unit, the spring unit comprising a spring retainer operatively interconnected to the switch unit, an actuator carried by the housing and a compression spring having opposed ends respectively bearing against the actuator and the retainer, the retainer having an intermediate part disposed in the opening of the housing and having a surface and a projection extendType: GrantFiled: June 8, 1992Date of Patent: March 30, 1993Assignee: Robertshaw Controls CompanyInventors: William J. Kaigler, Thomas M. Buckshaw, David T. Llewellyn
-
Patent number: 5140742Abstract: A pressure operated switch construction and method of making the same are provided, the pressure operated switch construction comprising a housing having an external surface and carrying an electrical switch unit and a diaphragm assembly therein, the housing having an opening passing through the external surface thereof, the electrical switch unit having opposed sides and an opening passing therethrough in alignment with the opening of the housing, and a compression spring unit carried by the housing and being operatively associated with the electrical switch unit and the diaphragm assembly to control the operation thereof in relation to the compression setting of the compression spring unit, the compression spring unit comprising a retainer operatively interconnected to the electrical switch unit, an actuator carried by the housing and a first compression spring having opposed ends respectively bearing against the actuator and the retainer, the retainer having an intermediate part disposed in the opening ofType: GrantFiled: November 20, 1991Date of Patent: August 25, 1992Assignee: Robertshaw Controls CompanyInventors: William J. Kaigler, Thomas M. Buckshaw, David T. Llewellyn
-
Patent number: 5136129Abstract: A pressure operated switch construction and method of making the same are provided, the pressure operated switch construction comprising a housing having an external surface and carrying an electrical switch unit and a diaphragm assembly therein, the housing having an opening passing through the external surface thereof, the electrical switch unit having opposed sides and an opening passing therethrough in alignment with the opening of the housing, and a compression spring unit carried by the housing and being operatively associated with the electrical switch unit and the diaphragm assembly to control the operation thereof in relation to the compression setting of the compression spring unit, the compression spring unit comprising a retainer operatively interconnected to the electrical switch unit, an actuator carried by the housing and a compression spring having opposed ends respectively bearing against the actuator and the retainer, the retainer having an intermediate part disposed in the opening of the hoType: GrantFiled: February 14, 1990Date of Patent: August 4, 1992Assignee: Robertshaw Controls CompanyInventors: William J. Kaigler, Thomas M. Buckshaw, David T. Llewellyn
-
Patent number: 4993144Abstract: A cyclable electrical switch construction, a system utilizing the switch construction and methods of making the same are provided, the cyclable electrical switch construction comprising a housing having a cyclable electrical switch therein and a rotatable actuator shaft that extends from the housing for setting the duty cycle of the switch in relation to the rotational position of the shaft in either rotational direction thereof from an "off" position thereof, and an electrical switch unit being carried on the housing and having structure operatively interconnected with the shaft so that the switch unit is actuated from one condition thereof to another condition thereof only when the shaft is rotated from the "off" position thereof in one rotational direction thereof.Type: GrantFiled: September 19, 1989Date of Patent: February 19, 1991Assignee: Robertshaw Controls CompanyInventors: David T. Llewellyn, William J. Lichtenberger
-
Patent number: 4883983Abstract: A cyclable electrical switch construction, a system utilizing the switch construction and methods of making the same are provided, the cyclable electrical switch construction comprising a housing having a cyclable electrical switch therein and a rotatable actuator shaft that extends from the housing for setting the duty cycle of the switch in relation to the rotational position of the shaft in either rotational direction thereof from an "off" position thereof, and an electrical switch unit being carried on the housing and having structure operatively interconnected with the shaft so that the switch unit is actuated from one condition thereof to another condition thereof only when the shaft is rotated from the "off" position thereof in one rotational direction thereof. The cyclable electrical switch is used in a plural load circuit, preferably, as a control of a dual wattage heating element of a cooking unit.Type: GrantFiled: July 8, 1988Date of Patent: November 28, 1989Assignee: Robertshaw Controls CompanyInventors: David T. Llewellyn, William J. Lichtenberger
-
Patent number: 4800633Abstract: A method of making a water level control device comprising the steps of forming a frame to have a substantially flat frame plate with opposite sides and with an elongated slot passing therethrough and having a first portion, forming a movable cam follower to be carried by the frame for setting the desired water levels to be provided by the device, forming a slide cam member to have a projection extending through the slot to guide sliding movement thereof relative to the frame, forming the projection means to have an interlocking unit interlocking with the frame while the projection is disposed in the first portion of the slot, forming the cam member to have a cam surface engaging the cam follower to set the same in desired water level setting positions thereof when the projection is in the first portion of the slot, forming the slot to have a second portion thereof for unlocking with the interlocking unit when the projection of the cam member is disposed in the second portion whereby the cam member can be easType: GrantFiled: July 8, 1987Date of Patent: January 31, 1989Assignee: Robertshaw Controls CompanyInventors: Thomas M. Buckshaw, David T. Llewellyn
-
Patent number: 4696204Abstract: A water level control device and method of making the same are provided, the device comprising a frame provided with an elongated slot having a first portion, a movable cam follower carried by the frame for setting the desired water levels to be provided by the device, and a slide cam member having a projection extending through the slot to guide sliding movement thereof relative to the frame, the projection having an interlocking part interlocking with the frame while the projection is disposed in the first portion of the slot. The cam member has a cam surface engaging the cam follower to set the same in desired water level setting positions thereof when the projection is in the first portion of the slot. The slot has a second portion thereof for unlocking with the interlocking part when the projection of the cam member is disposed in the second portion whereby the cam member can be easily detached from or attached to the frame.Type: GrantFiled: April 29, 1986Date of Patent: September 29, 1987Assignee: Robertshaw Controls CompanyInventors: Thomas M. Buckshaw, David T. Llewellyn