US1275168A - Brake for fire-shutters. - Google Patents

Description

E. H. McCLOUD.

BRAKE FOR FIRE SHUTTERS.

APPLICATION FILED JULY 23.1915.

Patented Aug. '6, 19l8.

I iii- A Iwa 11 roz EDWARD H. MGCLOUD, OF COLUMBUS, OHIO.

BRAKE FOE FIRE-SHUTTERS.

ravages.

Specification of Letters Patent.

Patented Aug. a, rare.

Application filed July 23, 1915. Serial No. 41,532.

' To all whom it may concern:

Be it known that I, EDWARD H. MoCLoUo, a citizen of the United States, residing at Columbus, in the county of Franklin and State of Ohio, have invented a certain new and useful Improvement in Brakes for Fire- Shutters, of which the following is a specification.

This invention relates more particularly to that class of automatically closing shutters in which the curtain is normally balanced for raising and lowering and the invention has for its object to provide an improved brake adapted to operate when the curtain is automatically released for closting. j

The invention is embodied in the example shown in the accompanying drawing and set forth in the following specification.

In said drawing Figure 1 is an end view in elevation with parts broken out showing the brake set to permit ordinary operation of the shutter.

Fig. 2 is a front view.

Fig. 3 is an end view in elevation illustrating the brakereleased for operation.

Fig. 4 is a sectional view.

Fig. 5 is a detail of brake members.

In the views 6 designates one end of the curtain roller and 7 a bracket for supporting the shaft 8 of said end of the curtain roller. Secured to the end of the shaft 8 where it projects beyond the bracket and to rotate with the shaft is a ratchet wheel 9 having a hub sleeve 10. Loose on said sleeve is a spur gear wheel 11 carrying a pawl 12 pivoted so as to be capable of engaging a tooth of the ratchet. Said pawl has an extended heel 13.

Journaled on a suitable bearing 14 extending from the bracket below the spur gear 11 is a pinion 15 having fixed therewith a cross plate or frame to the opposite ends of which are loosely pivoted on pins 16 two brake shoes 17 The shoes 17 have inward projections 17 at their free ends. Also pivoted on said pins 16 are arms or levers 18 having cams 18 near their pivots and weighted por tions 18 at their free ends. The cams 18 are located to press,'when turned outward,

upon the projections 17 at the free ends ofthe shoes. Springs 19 connect the arms 18 with the pins 16, said springs tending normally to hold the cams 18 out of engagement with the projections 17.

Mounted in the bracket 7 is a weighted lever 20 having connected with its inner end a short arm or dog 21 arranged so that when the weight lever 20 is elevated to horizontal position it extends into the path of the heel 13 and holds the pawl 12 disengaged from the ratchet 9. The lever 20 is held elevated by means of a wire 22 containing a portion 23, fusible by a dangerous rise of temperature, said wire being secured to a suitable fixed point above.

When the parts are arranged, as shown in Fig. 1, the shaft of the roller is free to turn without operating the brake at all. When the weight lever 20 is released, as by a nearby fire, the pawl 12 is thrown into engagement with the ratchet 9 and thegear wheel 11 caused to rotate with the shaft of the roller. Rotation of the gear wheel 11, of course, causes rotation of the pinion 15, and the impulsion outward by centrifugal force of the brake shoes and the arms 18 with the cams 18 The pressure of the cams 18 on sion of .a suitable hood 25 for the brake mechanism.

In the normal position of the parts, which is that shown in Fig. 1, the shutter or ourtain attached to the roller can be rolled up and unrolled as desired without operating the brake at all, because the shaft 8 of the. shutter and the ratchet wheel 9 attached thereto run idly in the spur gear 11. When, however, the pawl 12 is released as by the melting of the fusible portion or member 23 and the lever arm 20 drops the pawl 12 swings into engagement with the ratchet wheel 9 and thus operatively unites the shaft with said spur gear wheel 11 and causes it to turn and through it the pinion 15. The rapid rotation of the pinion 15 throws out the brake shoes 17 as well as the arms 18, and the cams 18 thereof acting on the free ends of the shoes, as illustrated in Fig. 2, engender a firm and extensive pressure of the shoes 17 on the brake rim 24 tending to prevent a too rapid unwinding of the curtain. It will be understood, of course, that where the curtain is one that is counterbalanced for raising and lowering in normal circumstances that thermally actuated means like that at 22-23 will be provided for liberating the counterbalancing means in case of fire and that such means can be arranged in position to operate simultaneously or nearly simultaneously with the means for releasing the brake. Indeed the samemeans, 2223 can be used to hold the counterbalancing spring latched from action.

The number and forms of the parts can be changed Without departing from the gist of the invention as claimed.

What I claim is 1. In combination, a shutter or curtain mechanism normally operable for raisingv and lowering, a brake and mechanism for operating the same associated With but normally operably disconnected from the shut ter or curtain, and thermally controlled means for operably connecting the shutter or curtain mechanism With the mechanism for operating the brake in the event of fire,

2. In combination With the shaft of a shutter or curtain, a brake mechanism to retard the closing movement of the curtain including a ratchet wheel fixed to said shaft, a driver loose With reference to said shaft, a pawl on said driver adapted to engage the ratchet, thermally controlled means for holding said paWl normally disengaged from said ratchet and a brake mechanism adapted to be actuated by the driver when the pawl is released to engage the ratchet.

EDWARD H. MCCLUUD.

Witnesses:

ELIZABETH M. Wnisz, ALBERT Rnsn.

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