US 2874240 A
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Description (OCR text may contain errors)
Feb. 17, 1959 M. RICKS AUTOMATIC DOOR-OPENING SIGNAL DEVICE Filed Feb. 21, 1958 INVENTOR.
MARC. R \c KS Arm-92:4 EYS United States Patent AUTOMATIC DOOR-OPENING SIGNAL DEVICE Marc Ricks, Berkeley, Calif.
Application February 21, 1958, Serial No. 716,617
1 Claim. ((11. 200-44) This invention relates to signal devices, and more particularly to a device for operating an electrical alarm responsive to the opening of a door.
A main object of the invention is to provide a novel and improved automatic signalling device adapted to provide an alarm responsive to the turning of a door knob on one side of a door, the device being simple in construction, being easy to install and being reliable in operation.
A further object of the invention is to provide an improved electrical alarm device adapted to provide a definite and unmistakable signal when a door knob on one side of a door is rotated, said device involving inexpensive components, being inconspicuous in appearance, and
involving a minimum amount of maintenance to keep it in operating condition.
Further objects and advantages of the invention will become apparent from the following description and claims, and from the accompanying drawings, wherein;
Figure l is a perspective view of a portion of a door including a door knob, showing the operating switch of a signal device according to the present invention mounted on the door adjacent the knob.
Figure 2 is a vertical cross sectional view taken on the 'line 2-2 of Figure 1.
Figure 3 is a vertical cross sectional view taken on the line 3--3 of Figure 2, showing the electrical circuit connections of the signaling system associated with the alarm switch.
Referring to the drawings, 11 designates a conventional door provided with a door knob 12 rotatably mounted thereon for opening same.
Designated at 13 is a sleeve member which is provided with a set screw 14 for securing same to the shank portion 15 of the door knob 12, the sleeve member being provided with a generally circular skirt portion 16 which overlies the annular escutcheon plate member 17 of the door knob, as is clearly shown in Figure 2, and is freely rotatable relative to said escutcheon plate.
Mounted on the door'11 below the escutcheon plate 17 is a normally open switch 18 having an operating plunger 19 projecting from its top edge, as is clearly shown in Figures 2 and 3, the skirt member 16 being cut away to define a flattened peirpheral edge portion 20 under which the plunger 19 is located when the door knob 12 is in its normal position. Thus, as shown in Figure 3, the flattened edge portion 20 is generally horizontal in the normal position of the door knob and the top end of the plunger element 19 is located immediately subjacent the flattened edge portion 20.
The top end of plunger 19 is preferably rounded to 2,874,240 Patented Feb. 17, 1959 define a cam-like surface adapted to be cammingly engaged by the periphery of the skirt member 16 when the door knob 12 is rotated.
As shown in Figure 3, the switch 18 is connected in circuit with a suitable source of current, for example, a battery 21, and a suitable alarm device such as a bell 22. Any other type of alarm device may be employed, for example, a signal lamp, a buzzer, or the like.
Thus, the alarm device 12 will become energized by the closing of switch 18 responsive to the rotation of the door knob 12 from the normal position thereof to a position such that the circular portion of the peripheral edge of the skirt member 16 engages the top end of the switch-operating element 19.
The door knob 12 preferably forms part of a conventional type of door knob installation wherein independently rotatable knobs are provided on opposite sides of the door, each of the knobs being efiective to open the door. Thus, rotation of the knob 12 will have no eflect on the knob on the opposite side of the door, and conversely, rotation of said knob on the opposite side of the door will have no efiect on the knob 12 and hence will have no effect on the switch 18.
From the above description, it will be apparent that a signal device has been disclosed which may be employed on one side of a door to provide an alarm when an attempt is made to open the-door from said one side. In this way, an alarm or signal indication is provided responsive to the rotation of the knob 12, for example, where the knob is located on the outside of the door, showing that a person is opening the door.
The device may thus be used as an alarm device for an oflice, home, or other establishment to announce the arrival of a person at the premises and to announce the opening of the door of said premises from the outside by such person.
While a specific embodiment of an improved signaling system for use on a door has been disclosed in the foregoing description, it will be understood that various modifications within the spirit of the invention may occur to those skilled in the art. Therefore, it is intended that no limitations be placed on the invention except as defined by the scope of the appended claim.
What is claimed is:
In a signaling system of the character described, a door, a door knob rotatably mounted on said door for opening same, a sleeve member secured to the shank of the door knob for rotation therewith and having a generally circular skirt element extending adjacent the surface of the door, said skirt element having a flattened peripheral portion, a signal switch mounted on the door below and spaced from the flattened peripheral portion of said skirt element, and an operating plunger projecting above said switch and spaced from the peripheral portion of said skirt element, said plunger being engaged by the remainder of the periphery of said skirt element upon rotation of the door knob.
References Cited in the file of this patent UNITED STATES PATENTS Krueger June 2, 1953