US2674307A - Electrically operated curtain fire screen - Google Patents

Description

April 6, 1954 R. cALMY 2,674,307

ELECTRICALLY ORERATED CURTAIN RIRE SCREEN Filed June 2e, 1951 Eye.

RA PH CAL/wy.

IN VEN TOR.

jeetje M ATro/eNL-y Patented Apr. 6, 1954 ELECTRICALLY ERl RATED CURTAIN FIRE C EE Ralph Calmy, Glendale, Calif.

Application June 26, 1951, Serial No. 233,622

2 Claims. (Cl. 16o-331) My invention relates to curtain type re screens of the kind having a traverse curtain mounted for sliding movement across the replace, and has as a particular object the provision of novel means for opening and closing such lire screens.

The invention will hereinafter be described with particular reference to the fire screen disclosed in my U. S. Patent No. 2,512,480 issued June 20, 1950, but it is to be understood that, while the invention is not necessarily limited to incorporation with that screen, reference may be made thereto for more detailed information as to structural features that may be thought necessary to the understanding of the present invention.

Curtain type re screens are made with metal screen curtains, and in order to insure proper functioning thereof, should be provided with means to move the relatively heavy screens with a quick but even motion so that the mesh material will drape properly, similarly to window drapes.

It is accordingly an object of my invention to provide electrically actuated mechanism for the purpose described, which operates mechanism in which frictional losses are reduced to a minimum,

so that a small motor can supply the needed power.

Fire screens of the type to which my invention relates require a supporting frame, providing a guideway for members supporting the curtains, or in which a rod is mounted from which the metal mesh curtains are slidably supported, the rod being secured in a horizontal frame member extending across the top of the fireplace and being preferably, though not necessarily, supported on vertical frame members. rIihe horizontal frame member serves to also cover the top of the curtains and the means by which they are suspended from the rod, as well as a chain by which they are moved back and forth.

It is another object of my invention to provide electrically operated means which are arranged so as to be hidden by the frame members of the fire screen, so that the appearance of the re screen is in no way detracted from, as Would be the case if the operating means were mounted, on the fire screen frame so as to be visible from the room.

A point requiring consideration in arranging the means requiring to be manipulated to open and close the curtains of curtain type fire screens mounted in a vertical frame is that there should be no danger of tipping over the screen when operating said means.

It is another object of my invention to provide switch means controlling the operation of electrical opening and closing means so arranged that no appreciable force is required to manipulate the switch, and the screen curtains may be moved to full open from closed position and vice versa by a single movement of the switch. The operating means are automatically stopped at completion of the screen movement so that no skill is required to operate the fire screen of my invention.

Since the movement of a curtain of the iire screen may be at times stopped by some obstruction, it is another object of my invention to provide operating means so arranged that no damage is caused by such a stoppage of the screen.

Still further objects and features of my invenf tion will hereinafter appear from the description of my invention read with reference to the accompanying drawings which illustrate an embodiment of the invention at present considered preferable by me.

In the drawings which are on a larger scale than full size:

Fig. l is a fragmentary back elevation of an upper corner of a curtain type fire screen fitted with electrically operated actuating means of my invention; the screen being indicated as in full open position.

Fig. 2 is an elevation of the same corner of the re screen as shown in Fig. 1 but viewed from in front; and with the screen shown in closed position.

Fig. 3 is a cross section on the line 3-3 of Fig. l, with curtains omitted.

Fig. 4 is a pictorial diagram showing switches controlling the electric circuit of the electrically operated screen.

Fig. 5 is a fragmentary detail view showing a pulley around which an endless chain, driven by an electric motor, is guided at one end of the top horizontal member of the frame of the rire screen.

Referring now to Fig. l, the numeral I0 indicates the top horizontal member of the frame of the fire screen, a vertical side member of the frame being indicated at Il, and a corner reinforcement member at I2.

It is to be understood that the frame of the fire screen may be constructed in any suitable way but for convenience and ease of fabrication, I prefer to utilize angle material, suitably strengthened at the upper corners with stamped reinforcing members, and supported by stands or feet secured to the lower ends of the vertical frame members. One face of the angle frame members is turned toward the room in which the fireplace is situated, while the other face is directed backwardly from the outer edge; an area hidden from View from any angle is thus provided in which are arranged the means support ing the screen and the means operating it.

As shown in Fig. 2, no indication of the operating means are observable from front or sidewards of the screen except a pair of small switch buttons I3 and I4, which, of course, are much less noticeable than the chain and two pull handles provided for manual operation of the curtain type screen disclosed in my Vpatent previously referred to.

A length of rod I5 is mounted in sockets I6` (Fig. 3) brazed or otherwise secured toward the upper ends of the vertical side members II. A pair of curtains, only a portion of the left hand one I'l being shown in the drawings, is slidably supported by a plurality of rings I8 threadedon the rod, the rings at the inward edge of each curtain being of greater thickness than the other rings for a purpose which will be later explained.

The outer edges of the curtains are connected by any suitable means, not shown, to the frame so that those edges remain in position behind the outer face of the side frame members.

The curtains are preferably formed from lengths of helically wound wire, each length being intermeshed with the lengths on each side. The upper and lower ends of each length of wire are connectedv to the ends` of the wires on each side by small interengaging loops, which construction enables the wires of the curtains to be collapsed y laterally together when in open position and provides a laterally pliant, yet stable construction when in position suspended from the rod I5.

The curtains are opened and closed by means of an endless flexible member 20, which 'for the purpose of ease of operation and installation, is preferably in the form of a ball chain. The ball chain is formed into an endless loop` by. means of a resilient connecting and tensioning member generally indicated at 2 I. The chain is mounted on two chain pulleys 22 and 23 arranged above the level of rod I5, so that one run ofthe loop extends along each side ofthe rod. Each run of the chain is connected to the inner edge supporting ring of one curtain, one connection being conveniently made with the member 2 I and the other by passing the edge ring of the screen through a h'ole drilled througha connector of the usual type used in ball chains. It may be pointed out that, since the inner edges of the screens in full open position do not reach the pulleys 22 and 23, the members connecting the ball chain with the inner edges of the curtains do not interfere with the free running of the chain on the pulleys. The pulley 22 is secured on a bracket 24 (Fig. 5) brazed to the corner reinforcing member I2 of the frame at the end thereof, opposite to the location of pulley 23, which is the drive element effective to move the chain in one direction or the other to open or close the screen curtains.

I prefer to provide smooth surfaced pulleys 22, 23 and mount the chain 20 on them under suiiicient tension to insure proper operation of the curtains under normal conditions While allowing the driving pulley 23 to slip relative to the chain, should the movement of either curtain be stopped momentarily by some obstruction, such as, for instance, a log from the fireplace rolling against a curtain or the curtain catching against any improperly positioned log.

While I may utilize Various arrangements to keep the chain 20 under proper tension, use of the member 2| is preferred for the sake of simplicity and the fact that no deflection in direction of the chain is caused, thereby avoiding additional friction.

The member 2I comprises two elongated U shaped elements 25, 26 nested together with their looped ends opposite one another andi having chain connectors 2l and 28 hooked into the loops. The ends of the elements 25, 26 are bent outwardly at a, 26a and engage against the outer faces of washers 29,30. A coil spring 3| under compression is mounted over the nested elements 25,'26i andbetween washers 29 and 30. The end balls of the length of chain are secured in connector membersA 2T and 28. The effect of the described construction of tensioning member 2I is to hold the chain on the chain pulleys under a degree of tension dependent on the strength of the spring which, of course, is chosen of sufficient strength to insure proper functioning under normal conditions.

The power means for the drive pulley 23, in the preferred embodiment of the invention, consists of a miniature permanent magnet direct current motor, generally indicated at 32, mounted on a bracket 33 secured as by brazing-v or by machine screws, to a vertical frame member II or to a corner reinforcing corner member I2. A worm 36 mounted on ther shaft of the motor engages a worm wheel `xed on the lower. end of a shaft 3G mounted vertically in a bearing block 3? secured to one side of the'projectingv arm 38 of bracket 33. lA spur gear 39 is fixed to shaft 33 above the bearing block, which" is provided with al lateral or offset extension`40. projecting to the opposite side of arm 38.

Drive pulley 23 is secured to the lower end of a short shaft 4I mounted vertically in the offset extension 43 of the bearing block, and a spur gear 42 is secured to the upper end of shaft 4I and meshes with spur gear 39. Thus, the whole driving unit of motor and transmission gearing from the motor shaft tothe drive pulley 23 is mounted on a single bracket and forms a compact sub-assembly which may be easily and accurately installed on a screen frame fitted with curtain v supporting rod, curtains,y and with a chain 'end J pulley 22.

The motor 32 is fitted with two terminalsA 43, 44, one leading the electric current to the motor winding, and the other being connected to ground, when the motor is rotating in one direction; while when direction of rotation of the motor is reversed, the functions of the terminals is reversed, the direction. of rotationl of themotor depending on the direction of current flow throughthe motor winding.

The necessary switching arrangement to supply electric current to one or the other terminal and connect the remaining terminal rto ground, may be arranged .in Yvarious ways, a suitable switch panel arrangement being shown in Fig. 4.

The panel 45 is of insulation material., such as hard rubber, and is mounted on the bracket arm 38 by machine screws passing through holes 46 drilled in the panel and engaging in threaded holes in the bracket. On the face of they panel two spaced apart, positive terminals 4l, 48 are positioned toward one edge of the panel,y and two negative terminals 49, Y5l) are positioned. toward the opposite edgey and connected to ground.

A switch` arm- 5I- is pivotally mountedon-the panel by a stud 52 and is fittedfwithapositivel contact 53 adaptedrto engage with either panel positive terminal 4l or 48. The opposite end of switch arm 5I is iitted with two negative con tacts, one 54 adapted to engage with panel negative terminal 5B when arm 5I is in position to engage contact 53 vand terminal 41. A second negative contact 55 is mounted on arm 5I and is adapted to engage with panel negative contact 49 when arm 5I is in position to engage contact 53 and terminal 48. Both contacts 54 and 55 are connected to the re screen frame as ground through terminals 50 and 49.

The arm 5I is rocked about its pivot in one direction by a plunger 5S pivotally connected at its lower end to arm 5I by pin 55a, the plunger passing through a hole drilled in the horizontal top frame member Il) and having the push button I4 secured on its upper end.

The arm 5I is rocked in the opposite direction by a second stem 5l pivotally connected to the arm on the opposite side of the pivot of the arm at an equal distance thereto by pin 51a as the connection of plunger 56 to the arm. Plunger 5l' passes through a hole drilled in the frame member I0 and the push button I3 is secured to its upper end.

The arm 5| is maintained in either operated position by a spring 58 arranged under compression between a head 59 on a pin 50 pivoted at 6I, to the arm at a point in the transverse axis 0 passing through the pivot aXis of the pin but spaced from said pivotal axis, and an abutment 62 pivoted to the panel 45 in a line Vertical to the axis of rotation of the arm 5I and perpendicular to the longitudinal axis of the switch arm. Pin G passes through a hole drilled in the abutment. The described arrangement results in the spring being placed under maximum compression when the pivotal axes of the switch arm, pin and abutment are in line, which can only occur as the arm is moved from one position to the other. In Fig. 4, for the sake of simplicity, the contacts mounted on the panel and on the switch arm as shown as of the face to face type, in which case the contacts mounted on the panel serve also as L stops limiting movement of the arm. I may prefer, however, to provide panel contacts of the wiping type and to provide stops to limit the movement of the switch arm.

The source of electrical energy shown in the spring contact member 65 mounted on, but insulated from, the frame member as shown at 55. A positive lead 51 of insulated wire is secured to battery contact 65 and is connected to the positive contact 53 of the switch arm. The battery pack 53 is supported on a bracket 5t secured to the vertical frame member, the cells of the pack being thereby grounded to the metal frame of the nre screen.

Leads 69 and 'I0 from the positive panel terminals 4l, 48 to the terminals 43, 44 of the motor are connected as shown in Fig. 4, lead l0 being also connected toswitch arm negative contact 54 by lead Il, and lead 89 being also connected to switch arm negative contact by lead l2.

The connections and switch provided will therefore cause motor 32 to rotate in one or the other direction, according to the position of the switch arm 5I.

In ordei to interrupt the circuit of the motor when the screen curtains have reached the full open or closed positions, a limit switch is positioned in the ground lead of negative panel terminals 49 and 55. Since these limit switches are identical, the description of the full open limit switch, generally indicated at 'I3 as shown in Fig. l, will serve to describe both.

The limit switch comprises a resilient strip I4 of conductive material secured to the horizontal frame member but insulated therefrom, as indicated at l5, the lead 73a from negative panel contact 50 being connected to strip lli. 4Strip 'I4 is bent downwardly so as to be engaged by the inner vertical edge supporting ring I8 of a screen curtain, and resiliently bears against the horizotally bent end of a fixed contact strip I6 secured in conductive relation to the top horizontal frame member. The length of strip 'I4 engaged by ring I8 is covered by insulation TI, such as a short iiattened length of hard rubber tubing. During movement of the screens to open position, a circuit from the battery through the described switch means to ground is therefore established, but this circuit is interrupted when limit switch 'I3 is opened. When the switch arm 5I is in its opposite "position, a circuit is established, causing the motor to rotate in the opposite direction, and therefore the motor moves the screen curtains toward closed position until the closed curtains limit switch (not shown), which is arranged to be operated by ring I8 on reaching the end of its inward movement, is opened, and the circuit interrupted. The limit switch may also be so formed as to provide a stop arresting movement or" the screen, if desired.

The electrical means operating the screen have been described as a direct current motor supplied by a dry cell battery, but it is obvious that the motor may be driven, if preferred, by the usual alternating house current; in the latter event, a small transformer and rheostat being mounted on the frame of the screen and an extension cord with plug being arranged for connection with a wall outlet.

In installing the iire screen of my invention, a size is chosen preferably larger than the fireplace opening so that said opening is fully uncovered when the curtains are opened. This also results in the protection of the operating means from the eiects of heat.

While the described embodiment of my invention provides a novel, simply operated, and effective nre screen, it is to be understood that various changes may be made in the described construction by those skilled in the art without departing from the scope of my invention as intended to be defined by the appended claims.

I claim:

1. A fireplace screen of the kind described, including: screen supporting means on which said screen is mounted for transverse back and forth movement; a reversible miniature electric motor mounted on and concealed from View from in front of the screen by said supporting means; means supplying electrical energy to said motor; a single manually operable switch controlling the direction of rotation of said motor; pulleys mounted on the back of said screen supporting means and similarly concealed from view; an endless length of ball chain mounted on said pulleys and connected to said screen at free edges thereof a reduction gear mounted on the screen supporting means and similarly concealed from view driven by said motor and driving a pulley around which said ball chain is trained thereby providlng a drive-capableof slipping to enable the motor toA continue to rotateuntill reversed n the event full movement of the screen in one direction orthe'other is prevented; and automatically operated limit switches effective to stopv the motor when the screen is fully closed and opened.

2. A flreplace screen as set; forthA in claim 1 and in addition comprising a common support; for the motor, gear reduction means and' the manually operable switch.

References Cit'edin the' le' of this patent UNITED STATES PATENTS Number Name Date Morris June 10, 1924 Kurner Aug. 10,1926 Armstrong Sept. 16, 1941 Valleny June 12, 1945 Calmy June 20,V 1950 Murphy Y May 222-,v 1951

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