US1295701A

US1295701A - Support for reflectors.

Info

Publication number: US1295701A
Application number: US19144017A
Authority: US
Inventors: James Deans Cumming
Original assignee: Individual
Current assignee: Individual
Priority date: 1917-09-14
Filing date: 1917-09-14
Publication date: 1919-02-25
Anticipated expiration: 1936-02-25

Description

J. D. CUMMING.

SUPPORT FOR REFLECTOHS.

APPLICATION FILED SEPT. l4. x911.

1,295,701. Patented Feb.25,1919.

' I OFFIE SUPPORT FOR REFLECTORS.

Specification of Letters Patent.

Patented Feb. 25. 1919.

- Application filed September 14. 1917. Serial No. 191.440.

To all who) it may com-rm.

Be it known that I, Janus l)l-IANS CUM- )uxo, of the town of (Topper Cliff, in the district of Sudbury. in the l 'rovinee of Ontario, Canada, have invented certain new and useful Improvements in Supports for l'leflectors, of which the following is the specification.

My invention relates to improvements in supports for reflectors particularly adaptable to parabolic reflectors and the object of the invention is to devise simple means --for supporting a reflector so that it may be adjustably swung around a center coinciding with the focal point of the reflector and the center of intensity of a stationar light source and it consists essentially of the following arrangement and construction of parts as hereinafter more particularly ex plained.

Figure 1, is a perspect ve view oi my support showing a reflector carried thereby, the

reflector being in vertical section.

Fig. 2, is a vertical section through Fig. 1 with the major portion of the reflect or broken away.

Fig. 3, is a plan view similar to Fig. 2.

In the drawings like letters of reference indicate corresponding parts in the various figures.

1 indicates a burner head provided, with a horizontally extending tubular portion 1 having a threaded exterior portion at its outer end. 2 indicates the burner, which is secured in the tubular portion 1 and from which a horizontally directed flame 2* extends when the burner is lighted, the center of intensity of the flame 2* being indicated by a cross 3.

a indicates a parabolic reflector, which is mounted so that the focal point of the reflector coincides with the center of intensity 3 of the light source represented by the It Will be readily understood that when using a reflector or more particularly a parabolic reflector with any light it is very desirable to keep the center of illumination as near the focal point of the reflector as possible. The reason for this is that to secure a ll'ltlXillllllll illumination the rays of light must be reflected from the surface of the reflector in a beam of parallel rays.

A parabolic reflector from its peculiar shape reflects all rays of light originating at its focal point in such a beam. Sinc the focal point of a parabola is of no'1nagnitude it is apparent that a light of any appreciable size can not be contained therein and, therefore. perfect reflection can never be obtained. If. however, the center oi in-v tensity of the light or flame be kept as close as possible to the focal point of the reflector the maximum etlieiency ot' reflection attainable will be obtained.

In order to swingably mount the reflector so as to obtain the above result, that is. keep the. center of swing. of the reflector, center of light source and the focal pointof the reflector coincident I have provided the following means for mounting the reflector upon the burner.

5 indicates a gland which is provided with an internal thread, which is screwed on to the external thread of the tubular portion 1 of the burner. The gland 5 is also provided with an external thread 5". (3 and 7 indicate lugs, which extend out from the dian'ietrically opposite sides of: the gland in proximity to its outer end or that end of the gland next to the burner 2. 4 indicates a slot, which is formed in the inner end of the reflector 4 and is vertically disposed. 8 indicates a bracket, which is secured to the reflector 4 at each end ot-the slot 1*, such bracket being provided with arms 9. 10, 11 and 12 extending outwardly from the cross bars of the bracket.

15 and l6 indicate are-shaped bar po tions, the bar portion being formed integral with the arms 10 and ll and the bar portion 16 with the arms 9 and 12. The

bar portions

15 and 16 are arc-shape in form and concentric with the focal point of the reflector 4' and the center of illumination oi the flame 2. 17 indicates an internally threaded annular nut. which is screwed upon the gland i and provided with wings l8 and l!) by which the nut is screwed into position.

When it is desired to attach the reflector in position all that it is necessary to do is to screw the' nut 17 upon the gland 5, the areshaped bar portions 15 and lti being inserted between the nut and the dian'ietrically extending lugs (3 and 7.

Vthen it is desired to adjust. the angle of the reflector 4- all that it is necessary to do is to loosen the nut 17 and swingthe reflector to the desired position. As the arc-shaped portions 15 and it; are concentric with the eenter of light source formed by the flame 2", Which corresponds also to the focal point of the reflector, the center of intensity of illuminationalways coincides with such focal point at any position to which the reflector is swung.

With a reflector, which is rigidly fixed to the source of light, it has always been necessary to swing both the reflector and source of light to change the direction of the light rays. By my'refiector holding device the direction of the rays of light may be changed without moving the source of light or removing the center of intensity of the light from the focal point of the reflector.

Although I have describerlany invention as particularly adaptable to a parabolic reflector it will, of course, be understood that it may be used with any other type which does not throw parallel rays of light, the

'bbject being no matter what type of reflector is used that when the reflector is swung so as to direct the beams of light at any desired angle that the center of swing of such reflector coincides with the center of illumination.

It will be understood that the arc-

shaped bars

15 and 16 are so disposed as to form sectors, the centers of which are located at each side of the center of illumination sothat the line joining these centers would pass through the center of illumination. By forming the slot 4* as above described the flame 2 passes horizontally from the burner through. the back of the reflector into the interior thereof, the slot being of such dimensions thatthe flame passes therethro'ugh no 1 matter at what angular position the reflector is set within the limits desired and so that the center of the flame coincides with the focal point of the reflector.

What I claim as my invention is:

1. The combination with the burner arm, of a parabolic reflector having an arc-shaped vertically disposed slot in the back thereof, arc-shaped bar portions concentric with the focal point of the reflector and carried by 45 the reflector and clamping means carried by the burner arm (lQSlgIlQd to engage each inner and outer edge of the bar portions to secure them in position.

2. The combination with the burner arm, of a parabolic reflector having an arc-shaped vertically disposed slot in the back thereof, arc-shaped bar portions concentric with the focal point of the reflector and carried by the reflector, a member carried by the burner arm having radially extending lugs adapted to extend against the inner edge of the areshaped bars, and a clamping screw designed to bear against the outer edge of the areshaped bars.

Witness: 7

G. E. BUCHANAN.