US1983830A

US1983830A - Decelerometer

Info

Publication number: US1983830A
Application number: US602679A
Authority: US
Inventors: Reginald J Alden
Original assignee: Individual
Current assignee: Individual
Priority date: 1932-04-02
Filing date: 1932-04-02
Publication date: 1934-12-11
Anticipated expiration: 1951-12-11

Description

R. J. ALDEN DECELEROME'IER Dec. 11, 1934.

INVENTOR Rae/mm JALms/v ATTOI ZMs'YSa' Filed April 2, 1932 Patented Dec. 11, 1934 UNITED STATES PATENT OFFICE Claims.

This invention relates to decelerometers of the general type disclosed in my copending application Ser. No. 526,603 filed March 31, 1931. Among the objects of the invention is to provide an instrument of this character so constructed as to make possible a relatively high degree of uniformity in the instruments as manufactured and at the same time permit of their being sold at a price well within the means of every car owner. These objects are accomplished by the form, arrangement and manner of assembly of the parts which in themselves possess advantages as will more fully appear from the following specification and claims:

In the accompanying drawing which illustrates one embodiment of my invention;

Fig. 1 is a front view of the instrument,

Fig. 2 is a side view,

Fig. 3 is a rear view.

Fig. 4 is a section substantially on line 4-4 of Fig. 1,

Fig. 5 is a, a plan view partly in section of the structure as shown in Fig. 3,

Fig. 6 is a section substantially on line 6-6 5 of Fig. 4,

Fig. 7 is a plan view of a blank from which one of the elements is formed,

Fig. 8 is a side view of the element formed from the blank of Fig. 7,

Fig. 9 is a plan view of the tube closure element, and

Fig. 10 is a diagrammatic view showing the electric circuit.

Referring to the drawing the instrument comprises a casing 1, preferably made of molded bakelite or the like, and provided on its face with window openings 2 and 3, respectively fitted with red and green panes 4 and 5 of celluloid, glass or other suitable material. The casing 1 is in the shape of a cylindrical cup, open at the back, and the window openings are each surrounded by inwardly projecting open ended cylinders 7, formed integral with the casing, which cylinders are of slightly larger diameter than the windows thus providing annular shoulders 8 against which the panes 4 and 5 fit as shown in Fig. 5. The panes may be made of a diameter to be held in position against the shoulders 8 by frictional en gagement with the walls of the cylinders '7 or 50 they may be held in place merely by engagement with electric light bulbs 10, annular felt or rubber cushions 6 being interposed between the bulbs and the panes as shown in Fig. 5. The bulbs 10 are held in the cylinders 7 by a metal cross bar 11 formed as shown in Fig. 7 with circular portions 12. The circular portions 12 are of a diameter, and are so spaced on the bar 11 as to fit in the inner ends of the cylinders 7 and are provided with central cross cuts 14 permitting the bending outwardly of points 15 adapted to frictionally engage the threaded sides of bases 16 of the bulbs as shown in Fig. 5. The edges of the cylinders are notched as at 1'7 to receive the bar 11, said notches preventing sidewise displacement of the bar. One end of bar 11 is extended and bent at right angles to the bar to form an electrical connection 18 which may be grounded as later described.

Intermediate the cylinders '7 and positioned diametrically of the casing 1 is a frame 20 in the general form of a truncated right triangle having a vertical side 21, parallel sides 22 and 23 extending at right angles to the vertical side 21 and connected by inclined member 24. The frame is preferably made of molded bakelite or the like and is so proportioned that the sides 22 and 23 frlctionally engage the sides of the casing l to hold the frame in position. The inner face of side member 24 of the frame is formed with an integral lug or shoulder 25 which engages the bar 11 intermediate the cylinders 'l to hold the bar, and thereby the bulbs and panes, in place.

A generally triangular channel 2'7 is molded in one side face of the frame and extends completely around the frame. The cross section of the channel is shown in Fig. 6, the bottom of the channel being substantially semi-circular as at 28 and terminating at its edges in flat shoulders 29 from which parallel side walls 30 extend outwardly to the side face of the frame. The bottom portion 28 of the channel is adapted to be covered, to form a closed endless tube, by a flat member 32 conforming to the shape of the channel and resting on shoulders 29. Member 32 is formed of some non-conducting material such as fibre or bakclite and is held in place by means of a non-conducting material 33 which is poured, in plastic form, between the walls 30, and on top of member 32, and permitted to harden.

Before the channel 2'7 is closed by member 32 and sealed as above described a measured quantity of mercury 35 may be placed in the channel or the mercury may be inserted after the channel is closed, as later described. Member 32 is provided with an opening 37 positioned in the vertical member 21 of the frame and with spaced opening 38 and 39 positioned in the inclined member 24. Through these openings are passed

electrical contact members

40, 41 and 42 respectively and these contact members are sealed in and held in place by the material 33.

As willbe clear from Fig. 4 the amount of mercury is made such and the

contact members

40, 41 and 42 are so positioned that when the instrument is mounted with member 21 of the frame vertical, the level of the mercury in member 21 is above contact 40, in other words contact 40 is immersed in the mercury, while the level of the mercury in the inclined member 24 is below both

contact

41 and 42.

Contact member 40, as best shown in Figs. 3 and 5, makes a spring contact as at 45 with the filament lead of the base of the bulb behind the red pane 4, while the contact member 41 makes a similar contact as at 46 with the bulb behind the green pane 5. The cross piece 11 which connects with the threaded sides of the bulb bases is grounded, as previously stated, by any suitable lead such as a wire, not shown, to the frame of the car, and through which it connects to one pole of the battery. Contact member ,42 is connected by any suitable conductor to the other pole of the battery.

Assuming the car'to be running at a uniform speed the condition of the instrument is illustrated in Fig. 4, where contact 40 is immersed in the mercury but

contacts

41 and 42 above the mercury level so no current flows to either light.

A sudden application of the brakes, arresting the forward movement of the car will cause the mercury, due to its inertia, to rise in the inclined tube, with the result that the mercury engages contact 42 while the mercury in the vertical leg of the tube is also still in contact with the mercury, thus establishing a circuit from the battery through contact 42, mercury 35, contact 40 to the red bulb 10 and through grounded bar 11 to the other pole of the battery. If the brakes of the car are in proper order the lighting of the red light is only momentary as the deceleration will cause the mercury to leave contact 40 entirely and cause it to rise into engagement with contact 41 thus closing the circuit from the car battery through contact 42, the mercury 35, contact 41 to the green bulb and through grounded bar 11 back to the battery. The lighting of the green signal lamp therefore indicates a proper operation of the brakes'while its failure to light and the continued burning of the red signal-indicates an insufficient rate of deceleration and defective brake operation. In order to provide means for inserting the mercury and also to permit adjustment of the degree of movement of the mercury in response to a givenrate of deceleration, a vent 50 is preferably tapped at the base of the inclined portion of the mercury tube and the vent provided with a closure screw 51 which may be of a length such that when turned inwardly the screw tends to obstruct the movement of the mercury, in the tube, the degree of the obstruction varying the degree of movement of the mercury in the inclined tube in response to a given rate of deceleration. The vent 50 also permits the addition of more mercury or its removal if a change in amount is required.

The construction described offers many manufacturing advantages. Casing 1 and frame 20 may be molded from bakelite at small expense, the contact members including bar 11 may be stamped from sheet metal. The assembly is quickly accomplished without requiring any substantial skill on the part of the workman. The apertures 3'7, 38 and'39, accurately fix the position of the contact members '40, 41 and 42 and when a me sure a unt 0? W W has been fi d in groove 2'7, and member '32, with the contacts sealed into the groove by the plastic material 33, frame 20 becomes a unit and the instrument is completed by dropping the panes 4 and 5 into the cylinders 7, sliding the light bulbs into the cylinders and forcing the frame 20 into the casing 1 with shoulder 25 engaging bar 11.

It will be understood that while for the purpose of illustration a specific arrangement of the electrical contacts within the mercury switch has been described to operate the light in a specific manner, the present invention is not limited to such arrangement but is directed broadly to the manner of supporting and assembling the casing, panes, light bulbs and mercury switch, and that the switch, may be so constructed, as respects tion of the contacts to the bulb terminals, to provide any desired sequences of operation or nonoperation of the light without departing from the-scope of the invention. What I claim is:

1. An instrument of the character described which comprises a cylindrical casing formed of non-conducting material, said casing being open at the rear'and provided on its front face with two spaced window openings, cylindrical members projecting inwardly'from'said opening, a pane of transparent .material and an electric light bulb supported ineach of said cylindrical members in alignment with the adjacent window opening, a bar bridging the inner ends of said cylindrical members to retain the panes and bulbs within said members and forming an electrical contact with both said lights, a generally triangular, hollow frame frictionally engaged within the casing intermediate said cylindrical members, means carried by the frame and engaging the bar to retain the latter in place, a quantity of mercury within the hollow of the frame, a contact member extending through the wall of the frame andnormally in contact with the mercury and connected in circuit with one of said lights, a second contact member extending through the wall of the frame normally out of contact with the mercury and connected in circuit with the second of said lights and a third contact member extending throughthe wall of the frame at a point intermediate said first and second contact members, said bar and said-third contact member being adapted for connection to a source of electric current. I

2. A structure as in claim 1 in which th mercury container comprises an endless groove formed in one'side faceof the frame, the sides of the groove being formed with shoulders intermediate the depth of the groove, a closure member engaging said shoulders to form the bottom of the groove into an endless tube for the mercury, apertures inthe closure member to support the electrical contact members in their predetermined relation in the tube and means to seal the closure members, and the contactmembers supported thereby, in thegro'ove.

-3. A structure as in claim 1 including a screw threaded into the frame and projecting intothe mercury .containinghollow of the frame to provide an adjustable obstruction to the free movement of the mercury therein. I

4. An instrument of the class described which comprises a cylindrical casing formed of non- .conducting material, said casing being open at the rear and provided on itsfront face with spaced window openings, cylindrical members projecting inwardly from said openings and adapted to support a pane of transparent material and an electric light bulb in alignment with each of the window openings, a metallic bar bridging the inner ends of the cylindrical members adapted to retain the panes and light bulbs in position, said bar forming an electrical connection to one filament terminal of the light bulbs, a generally triangular frame frictionally engaged within the casing intermediate the cylindrical members, said frame having means engaging the bar to hold the latter in assembled position, a closed tube formed in the frame, a predetermined quantity of mercury enclosed in the tube, two spaced electrical connections positioned in the tube and formed to respectively connect to the second filament terminal of the respective light bulbs and a third electrical connection positioned in the tube, the amount of mercury in the tube and the spacing of the three connections in the tube being such that movement of the mercury will close the circuit between diiferent combinations of said electrical connections in said tube in a predetermined manner dependent upon the extent of the movement of the mercury in the tube.

5. An instrument of the class described which comprises a casing formed of non-conducting material, said casing being closed in front and open in the rear and provided with two windows in its front, an electric light bulb adjacent each window, a generally triangular, hollow frame fitted within said casing intermediate said windows, a metal bar holding the electric bulbs and forming a common electrical connection to one filament terminal in each of said bulbs, means on said frame for positioning said bar, a quantity of mercury within the hollow of said frame, two spaced electrical connections positioned within the hollow of said frame and formed to connect respectively with the remaining filament terminal in each of said bulbs, and a third electrical connection positioned within the hollow of said frame, the amount of mercury and the spacing of the three electrical connections within the hollow of said frame being such that movement of the mercury will close the circuit between different combinations of said electrical connections within said frame in a predetermined manner dependent upon the extent of the movement of the mercury within the said frame.

REGINALD J. ALDEN.